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Liste over projekter

Analyzing the new systematic errors in pressure setup
Bachelorprojekt, 1. modul, Vinter 2010, id:289
Vejleder:Kristine Niss
Findes på RUb:Ja
English abstract
The goal of this experimental project is to analyze the new systematic errors that have accrued in pressure setup in one of the laboratories of IMFUFA recently and also to elucidate whether the solution that has been suggested by one of the academic staff of physic departmnent is right or not. His idea is the problem has been caused by some conduction through the pressure oil that we model it with three leaking resistances. Our method was using the oil as a dielectric between plat of a capacitance and investigate its behaviour in different frequencies. The setup is available in one of the laboratories of IMFUFA and it consists of two different measurement methods. In some level of our work instead of liquid itself we use Debye model in our calculation. Even the debye model is too simple compared to the liquid but still gives some of its behaviour.

Isomorf kommunikation
Speciale, 3. modul, Sommer 2013, id:286
Vejleder:
Findes på RUb:Ja
Abstract
English abstract

Fra Storhed til Fald - en analytisk gennemgang af Steady State modellens historie
Refleksionsprojekt, Bachelor. modul, Sommer 2013, id:287
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
This project report explores the different phases that a specific physical model undergoes in its journey from conception to rejection. The purpose of the project is to understand how an idea is conceived, which challenges this idea may face, in the form of knowledge or a lack there of, religion, politics and academic competition, and how the scientist may bear witness to the falling apart of his fundamental belief in the light of new discoveries. The project describes the historical background of the Steady State model, and concurrently considers some of the strengths and weaknesses which defined the model at the time when it was still recognised as a potentially valid model of the universe. Subsequently, the project discusses how an idea for a new model may be attained, as well as the ideas that reinforce the model, and the one idea that ultimately proved the model invalid. Furthermore, the competition that was waged between the Steady State model and the Big Bang model is discussed, in order to achieve an understanding of the ways in which this competition influenced the development of the Steady State model. The project concludes that no definite answer exists as to how the idea for the creation of a new model is attained, as there may be a vast array of reasons for the emergence of an idea. Finally, it is concluded that the competition between the models has only meant that none of the models garnered a significant majority of supporters until scientific experimental substantiation of the Big Bang model was established.

Er dimensionsanalyse Vanskeligt?
Refleksionsprojekt, Bachelor. modul, Sommer 2013, id:288
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
This project is a pilot project that examines the difficulties that arise when a group of students solves problems by dimensional analysis. The project puts up two hypothesis', which respectively states that it will be difficult to choose the correct variables, and analyzing the exercises will be tough without the necessary level of known theory in a given subject. The basis of the study is made from a video recording of four Bachelor students from Roskilde University. The participants are asked to solve four different exercises, each of which is selected in the matter of their difficulty level and topic. These video recording gets transcribed from which an analysis is made of the following: Their structure and order, their analysis of the exercises, their choice of variables and the mathematical treatment. This is used in a discussion of the difficulties they have with the exercises while doing dimensional analysis, as well as a discussion of the method in which these empirical data is collected. The project concludes that participants in this study overall experience difficulty with analyzing the exercises they have been asked to solve, and as a consequence of this, they experience it to be difficult selecting the correct variable, to do dimensional analysis. Also the conclusion indicates that the students have a harder time solving exercises which deviates from exercise they have experienced in the past.

Fysik og Astronomi - to supplerende videnskaber
Refleksion, 1. modul, sommer 2004, id:218
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Nej
Abstract


Internt-faglig, 2. modul, sommer 2004, id:219
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
The RMC-model is a lattice model of a viscous liquid, where each particle is assigned a unique energy landscape. The equilibrium-dynamic of the model is investigated through MonteCarlo-simulations, where only nearest-neighbour jumps and no overlapping of particles is allowed. Simulations were made for three different densities for a number of temperatures. At high densities and low temperatures the model exhibits non-exponential relaxation in the energy correlationfunction and fragility-plots of the temperature dependent diffusion constant and of relaxation times show non-Arrhenius behaviour. A monitoring of time-development of distribution of particle-displacement shows, that a Gaussian approximation is reasonable at high temperatures in all densities, while gradual shift towards a "broader" distribution, where som particles remain trapped for long times, while others are very mobile, is seen with decreasing temperature. These results lead to the conclusion, that the model captures some of the important charactaristics of a viscous liquid.

Technological Driving Forces and Barriers for the Dissemination of Degassing Technology in the Oil Industry - The case of the DONG degassing plant
Speciale, 3. modul, , id:283
Vejleder:
Findes på RUb:Ja
English abstract
This thesis examines the effect of installing the DONG degassing plant in 2009. The evaluation focuses on the environmental, technical and economic aspects of the technology. The effect of the degassing plant on the environment is evaluated through a tracer release experiment using acetylene (formel) as a trace gas to determine the change on emission as a result of installation of the degassing plant. This is used as a basis for modelling the VOC concentration distribution on the northern hemisphere using the DEHM model. The concentration data are subsequently used in a 1-D RCM for modelling the change in radiative forcing as a result of the installation of the DONG degassing plant. The technical aspect is evaluated through a determination of the inherent availability and the energy-production relationship determined from production data. The economic aspect is evaluated through a cost-benefit analysis with stakeholders being respectively the users of the oil pipe and the society. Due to the small amount of measurements performed in the present project, the environmental effect of the installation of the DONG degassing plant remains inconclusive. Based on earlier measurements the modelling show a concentration change as a result of the change in emission of up to (formel) ppm with the majority concentrated around Fredericia. The inherent availability is shown to have been 96% in the period from the installation of the plant to August 2012, approaching 98% over time. The energy per produced to offgas is shown to be 0.58 MWh/ton. The net present value of the installation of the degassing plant is shown to be approximately zero for the users of the oil pipe and positive for the society.


Fagprojekt, 4. semester. modul, 2014, id:292
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract
Chocolate has to be tempered properly to give it the desired properties. Badly tempered chocolate can be a whitish and have a matt finish, it can be gritty, too hard, too soft, and may not melt in your mouth. This project performs differential scanning calorimetry measurements on cocoa butter to try to explain what happens during a tempering of chocolate using known theory about crystal formation, structure and stability. Getting the DSC-device to function properly was a large part of the experimental work. Not surprisingly did the DSC measurements suggest that coca butter before tempering did not contain the desired stable crystals. Experiments with tempering of chocolate were performed in order to find a method that could be transferred to at DSC simulation. The method that was found and simulated, failed to provide (formel)-crystals which are the crystals that are desirable in a good chocolate. It could also not be verified that a slow cooling rate and frequent stirring gives the desired properties of chocolate when tempering at home.


Speciale, 3. modul, 2014, id:293
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract


Speciale, 3. modul, 2014, id:294
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
The aim of this thesis is to investigate quantitatively the expectation that physics students have more difficulties applying nomological than causal explanations during problem solving in physics. In a nomological explanation a phenomenon is explained from a general law under the circumstances present, and the phenomenon is a manifestation of this general law. In a causal explanation a phenomenon is explained by the causes for the phenomenon under the circumstances present. Nomological explanations are essential in physics, because they say something about the phenomena in relation to the world view of laws in physics. The theoretical framework of this study is ressource-based in the sense that it is designed to measure how a numner (N = 90) of physics students with the necessary domain-specific knowledge accessible manage to activate nomological and causal resources in two specific problem-solving situations, respectively. The respondents are at the undergraduate level at the end of their first year. In general, the respondents showed difficulties in solving the problems. Hence it was necessary to examine how they managed to solve the problems' constituent elements with nomological and causal solution frames, respectively. Here there was a tendency that the students displayed more difficulties applying nomological than causal reasoning.

Simulation of DNA-induced Self-assembly of Nanoparticles
Bachelorprojekt, 1. modul, 2014, id:301
Vejleder:
Findes på RUb:Ja
English abstract
DNA-functionalized nanoparticles have been suggested as a potent way to create various nanostructures. In this theoretical project we have investigated two models, a lattice model and an off-lattice model that is one modelling particles on a grid and one modelling freely moving particles. The models have been used to investigate behaviour of functionalized particles under different densities and temperatures, using the Monte Carlo algorithm to simulate Brownian motion. DNA strands are modelled on a coarse grained level with one length parameter and one energy parameter. We investigated nine realizations of functionalized particles, with strands aligned along the Cartesian coordinate axes. The model is parametrized using experimental results from literature. We show that the modelled particles assemble into ordered structures for temperatures between the boiling and freezing point of water. Particles assemble into four types of ordered structures; either expanding in one, two or three dimensions, or clusters. There is a particular interval of temperatures and densities at which these structures assemble. At temperatures not in the interval, particles assemble into disordered structures. The range of the temperature intervals decrease with increasing number of DNA strand attached to the particle. Lastly, we present a comparison of the two models and how realistic they are. We argue that both models are adequate for modelling single DNA strands, however, if there are multiple DNA strands attached to a particle, the lattice model was found to yield realistic result only in some cases since it cannot represent orientational disordered structures.


Bachelorprojekt, 1. modul, 2014, id:302
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
This paper examines the role of notation in physical modelling. Based on conversations with experimental physicists from the NSM institute on Roskilde University, the examination is delimited to include the use of analogous electrical network diagrams in modelling of physical systems. There is tradition among experimental those physicists at to use energy bond graph techniques - including electrical network diagrams - to determine in- and output of dynamical systems. As a starting point of examination of those electrical network diagrams, a representative model of an electro-acoustical loudspeaker is set up, both with the notation of differential equations and by means of electrical networks. The two modellings of this oscillating system has a purpose of expressing the electrical admittance across the terminals of the loudspeaker. The methods which are applied to the use of the notations are explicitly accounted for. An analysis in terms of C.S. Peirce's semiotic categories, of the model representations, are being held together with advantages as they were proposed by the users of energy bond graphs. The found potential of icon based modelling tools are put in relation to the transcendental philosophy of Kant and the relation between form and understanding. It is concluded that networktechniques are useful in modelling of physical systems because the diagrams appeal to both rationality and sonsory experience.


Bachelorprojekt, 1. modul, 2014, id:303
Vejleder:
Findes på RUb:Ja
Abstract
English abstract

Developing a Method for Luminescence Dating of Rock surfaces
Integreret speciale (kemi), 3. modul, 2014, id:305
Vejleder:
Findes på RUb:Ja
English abstract
Interest in the optical luminescence dating (OSL) of rock surfaces has increased significantly over the last few years, as the potential of the method has been realised. In this study we investigate the information available in blue-stimulated luminescence depth profiles into the surfaces of 4 quartz-rich cobbles from a Neanderthal site (Les Roches d*Abilly) in western France, and IR stimulated luminescence depth profile from a feldspar-rich granite whetstone from an Iron Age villages near Aarhus in Denmark. These profiles show qualitative evidence for multiple daylight exposure and burial events. To quantify both burial and daylight exposure events a new model is developed. The existing model describing the evolution of luminescence depth profiles is expanded to include burial before and after light exposure, and the possibility of repeated sequential daylight exposure and burial events. By determining the burial ages from the surface layers of the cobbles and by investigating the fittet luminescence profile, it is concluded that all cobles were apparently well bleached before burial. This indicates that the estimated burial ages are reliable. In all cases the burial age of the most recent burial event is consistent with the expected age (quartz OSL on sediments from Les Roches d'Abilly and archaeological context for the Aarhus site). In addition, a recent known daylight exposure event provides an approximate calibration for daylight exposure events. This study thus confirms the suggestion that rock surfaces contain a record of daylight and burial history. Rock surfaces can therefore be dated with confidence, and it may be possible to determine a daylight exposure history using a known natural light exposure as calibration. Besides developing and applying the mathematical model, a preparation method for the samples used in this study has been developed. This development was based on knowledge of the chemical structure and properties of quartz and feldspar, together with X-ray fluorescence (XRF) measurements of full rock slices before and after chemical treatment. i9t is concluded that, on order to extract pure quartz grains from the French samples, hydrogen chloride (HCl) should be added before etching with hydroflouric acid (HF). If HCl is not used first to remove calcium carbonate from the rock slices, HF can not attack and remove feldspar grains. It is also shown that the absence of feldspar in XRF analysis does not necessarily indicate that there is no infrared luminescence sensitivity, indicating that feldspar has not been completely removed.

Heterogenous Precipitation of Barium Sulphate - Dependence of Pressure and Electrical Fields
Speciale, 3. modul, 2013, id:284
Vejleder:Tage Christensen, John Mortensen og Niels Falkenberg
Findes på RUb:Ja
Abstract
English abstract
Scaling in oil fields gives rise to major problems with both restriction of the flow and blocking of important infrastructure such as vents. This study examines the possibilities for non-chemical inhibition of the scaling salt barium sulphate. The first part of the study investigates the effect of a static electrical field on the precipitation of barium sulphate onto a copper surface. Experiments were carried out in a copper pipe. A potential difference was applied between a silver electrode inserted into the pipe and the pipe itself. The results here were not within a statistically significant region to say anything conclusive. But a tendency did seem to form that with a positive potential on the copper pipe in relation to the silver electrode inside the fluid precipitated a little less onto the pipe. The second part of the study considered the pressure profile around different geometries in a pipe. This was done by modeling in COMSOL. Both a laminar flow model and a turbulent flow model were considered. The pressure profiles were then compared to earlier studies on the solubility of barium sulphate at different pressures. This showed that constrictions in the pipe gave a lower pressure near the wall in the middle of the construction, this was most significant in turbulent flow models with pressure drops up to around 1000 Pa. During laminar flow the changes in pressure were so small, the largest drop achieved being 0.06 Pa, that no scaling is assumed to take place, whereas during turbulent flow the pressure differences were larger and scaling may occur.


Speciale, 3. modul, 2013, id:285
Vejleder:Jeppe C. Dyre
Findes på RUb:Ja
Abstract
English abstract
It has been shown [1] that for liquids exhibiting strong correlation between its NVT virial and potential energy equilibrium fluctuations, one can, to a good approximation, define isomorphic curves in the density-temperature phase diagram, along which structure, dynamics, excess entropy, heat capacity etc. are all invariant. We investigate this behavior via MD-simulations in the FCC-crystalline state for Lennard-Jones systems and show that the strong correlation here is even more pronounced than for the liquid. This implies that isomorphic curves exist in the crystal phase, as well. We confirm this by studying the following predicted invariance: (1) The structure via the radial distribution function and structure factor, (2) short-ranged dynamics via the velocity autocorrelation function, (3) long-ranged dynamics via mean-square displacement of crystal vacancies, (4) aging via the relaxations of the system after instantaneous jumps between isomorphic state points. In all cases we compare the results with similar results along isochors and isotherms. In addition we investigate sodium-chloride in the crystal phase modeled by a potential consisting of a Lennard-Jones and a Coulomb term in a FCC structure. This system exhibits correlations just below the limit of strong correlations, and as a consequence has less well-defined isomorphs.

The Dielectric Loss Strength Variation along an Isomorph
Speciale, 3. modul, 2013, id:290
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract


Speciale, 3. modul, 2013, id:291
Vejleder:Jeppe C. Dyre
Findes på RUb:Ja
Abstract
English abstract
The aim of this Master's thesis is to analyse a classical and simple model of a liquid. The analysis consists of two parts: a theoretical analysis based on the isomorph theory and computer simulations. The computer simulations is done in the RUMD software. RUMD is a program used to perform Molecular Dynamics. The analyzed model consists of particles with pairwise interactions. The interactions are governed by a pair potential which decrease exponentially with distance. The interest in the model stems from the fact that though neglecting quantum mechanical effects, the model is aligned with quantum mechanics in the sense that the force between the particles mimic the probability distribution of electrons in simple atoms. The main results consists of a (formel) phase diagram of the liquid including the two main isomorph theoretically variables: R and (formel). An area with crystallisation and a phase transition between fluid and crystal are identified. No phase transition from liquid to gas is found, but the model exhibits gas-like structure in regions of the phase diagram. Application of isomorph theory leads to an analytic expression of isomorph lines dependent on one free parameter, in the phase diagram. Different methods for choosing this parameter is tested by generating isomorphs from two state points: One in the liquid part of the phase diagram and one on the coexistent line which is found to be an isomorph line. Another method of making isomorph lines is tested and rejected. The method is based on an observed linear correlation between coordinates of isomorphic phase points in an area of the phase diagram.

The Dielectric Loss Strength Variation along an Isomorph
Speciale, 3. modul, 2013, id:304
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract

Karakterisering af vesikler ved dynamisk lysspredning
Bachelorprojekt, 1. modul, 2012, id:276
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract
The purpose of this project is to examine the effects of alcohol on the lysis tension of DMPC vesicles. By extruding multilamellar vesicles, we obtain a monodisperse solution of unilamellar vesicles. By varying the amount of alcohol in the membrane we expect a change in the lysis tension. A model of the extrusion process suggest that this change in lysis tension will affect the size of the extruded vesicles. We measure the hydrodynamic radius of the vesicles by dynamic light scattering. Our results are inconclusive and we suspect systematik errors in the experiment. We are not able to draw conclusion about the proposed model. Based on difficulties in the experiment, we discuss sources of errors and uncertainties, in an attempt to pass on our experiences with dynamic light scattering experiments.

Implementering af uformaliserede opgaver i gymnasiet
Bachelorprojekt, 1. modul, 2012, id:277
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
The purpose of this project is to illuminate the effects and possibilities for implementing "unformalized problems" in physics education for high school students. This type of problem separates itself from the traditional problems by being open in its description, and therefore these kinds of problems require an active formalizing process. This process translates the everyday description of some physical scenario, into a well-defined system that is ready for further physical and mathematical analysis. This is a task high school students are unfamiliar with. For the investigation of unformalized problems effects and possibilities in high school context, an alternative course in physics has been developed and tested in a high school class within unformalized problems. During this course three ways of collecting data were used. The first was a FCI-test which was given to the students at the start and at the end of the course, to test their conceptual understanding. The second was a didactic analysis of about seven hours of video of the student's attempts at solving these problems. The third and last was a written evaluation from every student, with the students thoughts about and overall experience with the course. The project concludes that it is possible to implement these kinds of problems in a high school context. The students are capable of solving a large part of the problem by them self, and it is relative effortless as the teacher to lead them in the right direction, without handing them the solution to the problem. The FCI-test shows no progression in their conceptual understanding. The student's feedback of the course is positive and it is their impression that the course has indeed taught them physics, which align with our impression of the course.

Isochronal Superposition
Speciale, 3. modul, 2012, id:278
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract
This thesis investigates whether it can be shown experimentally if different types of liquids obey isochronal superposition. This investigation holds importance because a new theory, the isomorph theory, predicts that van der Waal liquids obey isochronal superposition. A definition of isochronal superposition, as well as those of Time-Pressure-Superposition and Time-Temperature-Pressure-Superposition, is established. Isochronal superposition is investigated for the dielectric relaxation spectrum. Dielectric measurements are made on four different liquids on a high pressure setup in relation to this project. Furthermore, data on two other liquids are included in this investigation. Two liquids studied are hydrogen bonded liquids, while four of them are van der Waal liquids. The high pressure measurement equipment used is relatively new and it is therefore first scrutinised before use in this thesis. Different measures, with the purpose of deciding to which degree a liquid obeys respectively isochronal superposition and Time-Temperature-Pressure-Superposition, are developed. These measures are based on the half width at half depth and the area deviation between the dielectric relaxation spectra. From these measures, it is concluded that the investigated van der Waal liquids obey isochronal superposition better than the investigated hydrogen bonded liquids. It is furthermore estimated that the investigated van der Waal liquids obey isochronal superposition and that some also obey Time-Temperature-Pressure-Superposition. It is concluded, that the studied hydrogen bonded liquids obey neither Time-Temperature-Pressure-Superposition nor isochronal superposition. The results follow the prediction of the isomorph theory and raises the question whether more liquids obey isochronal superposition. Further investigation could conclude whether van der Waal liquids in general obey isochronal superposition.

Modeller i fysik - Simplificering i modeller af gassers kinetik
Refleksionsprojekt, 1. modul, 2012, id:280
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
This project is written as a project of reflection over physics. It seeks to clarify how simplifications and assumptions in physical models is applied and justified. This problem statement is considered based on four models of the kinetics of gases; Boyle's static and dynamic model of air respectively; Bernoulli's model of ideal gases; Maxwell's model of the viscosity of gases; and the equation of state by van der Waals. This project gives an account for each of the models, which leads to a discussion of the background for the model including established experimental results at the time of the modeling, the perception of molecules expressed in the model and how the ideal gas equation is applied in the model. This project concludes that simplifications and assumptions in models are generally justified by a reference to empirical data consistent to the model and by physical and mathematical reasoning. Furthermore, simplifications and assumptions is generally applied in the model to create a simple representation of the observed phenomena.


Internt fagligt projekt, 2. modul, 2012, id:281
Vejleder:Tina Hecksher
Findes på RUb:Ja
Abstract
English abstract
This report deals with the ultra slow relaxation process (USRP) observed in many glass forming liquids. The temperature denpendance of the relaxation process is similar so the structural relaxation process it shows many of the characteristica of diffusion. The relaxation process is interpreted as the diffusion of "dynamic clusters" known as Fischer clusters. A photon correlation spectroscopy experiment is set up with the purpose of observing theese ultra slow relaxation process in the glass forming liquids o-Terphenyl (OTP) and glycerol. Regretably the attempt was unsuccessful, though it should be noted that the experiment correctly determines the diameter of a sample of (formel) nano spheres diluted in water. The reason for the failure is discussed but no concrete conclusion is reached.

Tube Resonance in the Bulk Transducer
Internt fagligt projekt, 1. modul, 2012, id:282
Vejleder:Tage Emil Christensen
Findes på RUb:Ja
Abstract
English abstract
Various experiments with liquids at varying column heights and temperatures were performed using the piezoelectric bulk transducer. The purpose was to understand the relation between the liquid column height in the tube and the unexpected tube resonance frequencies in the region between the Helmholtz frequency and the eigen frequency of the transducer. This would pave the way for a refinement of the existing model of the bulk transducer leading to a better fit for future experiments determining the bulk modulus of liquids in the transducer. Also, it could yield an interesting way to obtain clues about the relation between the thermal expansion and the resonance frequencies under scrutiny. The modelling of the tube resonances proved more complex than first envisioned and a satisfying fit of the obtained data to the suggested models needs further investigation. Also, the assumption that we are dealing with standing waves in the tube may have to be revised. However, the foundation is now laid for further investigation and refinement taking more parameters into account.


, 3. modul, 2012, id:298
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
In this project we investigate whether or not there excist correlations for a bead-spring model of a polymer melt. This project used computer simulation to investigate whether there were correlations between the virial and the potential energy. We conclude that there are no correlation for this type of molecular pair potential and the corresponding molecular virial. We conclude the project by presenting a model system, which presumably would have such correlations.

Measurement of Temperature Response to a Pressure Change (formel) of a Supercooled Liquid at the Dynamic Glastransition
Bachelorprojekt, 1. modul, 2011, id:271
Vejleder:Tage Christensen
Findes på RUb:Ja
English abstract
This report introduces an approach to characterizing thermal and mechanical properties of viscous liquids, by using a specific set up utilizing the coupling of a piezoelectric bulk modulus gauge (PBG) and a thermistor placed on a transverse wire through the PBG. More specifically we are using this set-up to investigate the temperature response to a pressure change of a supercooled liquid at the dynamic glass transition, as is also stated in the title. Physically this is achieved by applying a voltage on the liquid filled PBG, causing a volume displacement, which then in turn creates a pressure difference in the sphere. The report includes an introduction to supercooled liquids, viscosity and the glass transition. An introduction is also given to the energy bond formalism we use to derive a model for the experimental system (expressed in circuit diagrams). Based on this we derive transfer matrices that characterize the energy couplings of the thermodynamic, mechanical and electrical variables. Experiments are conducted with an empty PBG, a liquid-filled PBG and the latter utilizing the special conditions from the set-up with the thermistor and PBG coupling. From these experiments coupled with some approximations and generalized modelling, we are able to characterize various properties like capacitance and adiabatic compressibility. This data is used in conjunction with data determined in previous research to characterize the inverse of the adiabatic pressure coefficient. A significant amount of noise is detected in some experimental data. Also some unexpected development was detected in the frequency dependence of temperature change (formel) and the inverse adiabatic pressure coefficient (formel). Hovewer - concurrent independent experiments that use the same equipment but in a different manner show similar abnormalities in the data. This is indicating some "exo-model" influence that we have not accounted for. In spite of various abnormalities, the model is deemed viable for continued development, due to consistency with other similar studies and results.


Bachelorprojekt, 1. modul, 2011, id:272
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract

SAXS AND GISAXS OF LAMELLAR THIN FILM DIBLOCK COPOLYMERS AND SIMULATION
Bachelorprojekt, 1. modul, 2011, id:273
Vejleder:Dorthe Posselt
Findes på RUb:Ja
English abstract
Within the area of polymer science, polystyrene-b-butadiene diblock copolymers have become object of intensive studies. We have participated in a GISAXS experiment in DESY, Hamburg, using thin film samples of the same polymer with different thickness and chemical treatment. In the attempted to understand the data, programs have been developed to simulate virtual experiments of both SAXS and GISAXS of lamellar diblock copolymer thin films. The programs are used for simulation and visualization of scattering by samples, sucs as those used in the experiment. Based on the scattering theory, the virtual experiments yield realistic data, which could provide relevant information for future experiments. An alternative for future work within virtual SAXS and GISAXS imaging of lamellar thin films is proposed.


Speciale, 3. modul, 2011, id:274
Vejleder:Bo Jakobsen
Findes på RUb:Ja
Abstract
English abstract
This thesis examines advantages and disadvantages by using a cylindrical or planar geometry when measureing specific heat in the frequency domaine. By using transfer matrices the heat diffussion equation is solved for the heat diffusion from a infinite long cylinder, a infinite plane and a sphere, and the thermal impedance is found. Different limits and boundary conditions are examined. For small frequencies it is seen, that the thermal impedance for the infinite plane diverges faster than for the infinite cylinder. Furthermore for the infinite cylinder it is seen, that at low frequencies the specific heat and the thermal conductivity is decouple making it possible to measure the thermal conductivity. This is not possible for the infinite plane, where only the thermal effusivity can be measured. That being said, the infinite plane enables an isolation of the thermal effusivity, while for the infinite cylinder the specific heat has to be extracted from modified Bessel function by for example numerical fit.


Speciale, 3. modul, 2011, id:275
Vejleder:Dorthe Posselt og Jens Spanget-Larsen
Findes på RUb:Ja
Abstract
English abstract
The aim of this thesis is to aid in the understanding of the thylakoid. Thylakoid or thylakoid membrane is a term coined by W. Mente i 1960 for the internal chloroplast membrane system. The thylakoid is a complex membrane system divided into circular membrane stacks, called grana lamella, connected by fretlike membranes called stroma lamella. This is approached by investigation the thylakoid with 3 different methods; small angle x-ray scattering, transmussion electron microscopy, and spectroscopy. The investigated thylakoid systems are isolated from Pisum sativum and Arabidopsis thaliana commonly known as peas and blue in order to influence different parts of the thylakoid structure. The arabidopsis was mutated to inhibit the synthethis of a primary protein, which should show a major influence on the thylakoid system. The study focuses on the contribution of each experimental approach to improve the interpretation of the SAXS data through a model system. The model system choosen in the study is a model developed by Jens K. Holm to interpret thylakoid membrane flexability and changes from physico-chemical environmental change such as light induced effects and osmolarity. The model work well for the unchanged system without mutations or artificial light but struggles to interpret SAXS data obtained from thylakoid with artificial growth conditions.


Bachelorprojekt, 1. modul, 2011, id:279
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract
Woodwelding is a novel method used to connect two pieces of wood. One of several wood welding tecniques is linear wood welding where two pieces of wood are held together under high preasure while one of the wood pieces is shiftet linerly back and forth with a high frequency. This creates a bond of several megapasca between the wood pieces. It has been shown that the orientation of the grain has an influence on the streanght of the bond, but no explination has been given for this phenonema. This report is an attempt to shead some light on the matter. Softwood is mainly composed of tracheids which are long cylendrical cells. Inside the cell wall of theese tracheids one finds, amongst other things, microfibrils, which are long cellulose chain. The microfibrills form an angle with respect to the tracheid axis which is called the microfibrill angle. The microfibrill angle has an influence on the mechanical properties of the wood. We weld wood together with different orientation of the gain and measure the elastic modolus of the bond that is formed. The method used to investigate the structure of the bond at nanno scale is small-angle x-ray scattering. The microfibrill angle, the radius of the microfibrils and the elastic modulus was determined. The aim is to investigate the connection between the orientation of the wood grain during welding and the elastic modulus and nano structure of the bond. The elastic modolus changes with different orientation of the gain and our results suggest that there is a connection between the orientation of the grain and the elastic modulus. We find that the microfibril angle changes as one scans across the bond and the closer one gets to the center of the bond the higher the degree of disorder becoms. We found no clear connection between the change in microfibril angle, microfibril radius and the elastic modulus.


Bachelorprojekt, 1. modul, 2010, id:266
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract
Experimental studies and modelling of type IIb hydraulic jumps The aim of this project is to study a so far overlooked possible correlation between a physical model describing type IIa hydraulic jumps presented by Ellegaard et al. [1999] and observations of type IIb hydraulic jumps, also known as jumps in the cloverregime, presented by Bush et al. [2006]. The inspiration to do this investigation came from a mathematical study, presented in Hansen et al. [2002] of the model created by Ellegaard et al. [1999], in which solutions resembling structures found in the cloverre- gime are presented. Combining this with the later publication of Bush et al. [2006], we saw an interesting opportunity to study, whether the- se new solutions are able to describe the hydraulic jumps found in the cloverregime. In order to study this we have recreated type IIb hydraulic jumps experimentally and produced the two-leaf clover and three-leaf clover. From these observations we have gathered both quantitative and qualita- tive data, which are compared with an implementation of the model in Matlab. We conclude that the model reproduces certain characteristics found in type IIb hydraulic jumps. It corresponds well to an amount of new observations, but it needs further improvements, before it is able to give more than just qualitative descriptions of the phenomenon.


Frit projekt, 3. modul, 2010, id:267
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract
This project involves the introductionary work towards being able to test the hypothesis of existence of invariant isomorphs in strongly correlation viscous liquids. The principle in the experiment is to document the structural invarians along the isomorph using dielectric spectroscopy. Affiliated with this experiment is severel considerations, especially considering the time it takes to apply the change in temperature and pressure, compared to the time of relaxation of the liquid. We conclude that the time of relaxation should be of an order of magnitude ten times larger than the time it takes to perform the jump. Relevant predicted invariant isomorphs are localised, through a fit of measured data to the Vogel-Tammann-Fulcher and Avramov equations. Using these relevant points are determined for the specific experimental setup in the pressure-temperature phase diagram.


Speciale, 3. modul, 2010, id:268
Vejleder:Bo Jakobsen
Findes på RUb:Ja
Abstract


Speciale, 3. modul, 2010, id:269
Vejleder:Martin Niss
Findes på RUb:Ja

Development of Isothermal Microcalorimetry with in-situ Electrochemical Enzyme Sensors
Speciale, 3. modul, 2010, id:270
Vejleder:Tage Christensen
Findes på RUb:Ja
English abstract


Internt-fagligt, 1. modul, 2009/10, id:264
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract

Relaxationstid ved negativt tryk
Internt-fagligt, 1. modul, 2009/10, id:265
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract
English abstract

Femtosekund Laser Ablation
Intertfagligt, Modul 1. modul, 2009, id:262
Vejleder:Dorthe Posselt
Findes på RUb:
Abstract
English abstract


Frit projekt, 3. modul, 2009, id:263
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
Dynamics and structure of a viscous liquid is studied through computer simulation in the NVT-ensemble. The simulated liquid is a binary Kob & Andersen mixture interacting through modified Lennard-Jones potentials. The modification is that only the repulsive part of the potential between AA and BB interactions are included whereas there is an attractive part in the AB interactions. The liquid is found to be strongly correlating for the majority of state points investigated. This means that the correlation coefficient between the equilibrium fluctuations in virial and potential energy is above 0.9. The liquid obeys density scaling to good approximation. This means that the characteristic time in reduced units of the systems only depends on the densityp p, and the temperature T, through (formel) where(formel) is a constant that can be determined form the equilibrium fluctuations in virial and potential energy. There is found evidence of the existence of isomorphic state points. These are state points with the same structure and dynamics in reduced units. It is found that the explanation of how to find these state points is incomplete. Two models explaining the non-Arrhenius behavior of viscous liquids are investigated. It is found that the shoving model is inconsistent with the result of the simulations whereas the Landscape equivalent of the shoving model can not be rejected.


Internt-fagligt, 1. modul, 2008/09, id:259
Vejleder:Tage Emil Christensen
Findes på RUb:
Abstract
English abstract
This project examines measurements of the shearmodulus by the piezoelectricity shear gauge, developed by the research group "Glass and Time" at Roskilde University ]Christensen og Olsen, 1995]. In the calculations used so far [Christensen og Olsen, 1995], it is assumed that the liquid will contract towards the center, as the temperatur declines. This assumption is not necessarily correct, since the liquid at lower temperatures will be more viscous, and thus flowing slover in the transducer. As the liquid gets colder, it will contract. It will thus pull in the piezoelektric disc, and the disc will therefore bend. Then the liquid will flow towards the center, and the disk will return to its initial position, where transducer and the liquid will be in equilibrium. The time it takes for the system to reach equilibrium is dependent on the viscosity. We have thus ezamined the displacement of the piwzoelectric disk from its initial position as a function of time and temperature. Then we have calculated the significance for the calculation of the shearmodulus, and thus discussed the relevance of the reults for the experimentel method. In the project a model for the displacement of the liquid and the piezoelektric disc as a function of temperature and time is produced. We have concluded that there must be a change of calculations method at the temperature [T-anneal] which is 25-20 degrees above the glass transition temperature. In measurements above [T-anneal] the liquid will have tome to reach the center, thus the assumption used up until today is true. When measurements are made below [T-anneal] the liquid to contract by bending the disks downwards and the height of the liquid layer will change.


Internt-fagligt, 1. modul, 2008/09, id:260
Vejleder:Tage Christensen
Findes på RUb:
Abstract
English abstract

Effect of Pressure Equalization Modules (PEM) on Beaches
Speciale, 3. modul, 2008, id:250
Vejleder:
Findes på RUb:Nej
Abstract
English abstract
The effect of socalled PEMs (Pressure Equalization Modules) on beaches is examined through laboratorie experiments, computer modelling and beach profile analysis. The effect of a REM on drainage ability of a sand is examined in a self designet laboratorie experiment. The results of the experiment shows no significant effect of the PEM on drainage, but it is suspected that internal friction in the setup have affected the results to som degree. Computer modelling of s setup similar to the experimental setup shows a clear increase in drainage of around 10 percent as a result of insertion of a PEM. The increase depends on the hydraulic conductivity of the sand and is highest for the low conductive sand. Increased infiltration of around 40 percent was found for the low conductive sand, but this result results mainly from the unnaturally high pressure gradient in the model setup, and can not be directly translated into natural conditions on a beach. Modelling of the effect of PEM on a beach are carried out in a twodimensional profile model. The effects on wave induced beach groundwater circulation are examined for combinations of PEM and gravel layer. Circulation is found to increase between 5 and 11 percent for different sand types as a result of a PEM. The effect of a gravel layer alone is also an increase in circulation, and the effect is much larger for the low conductive sand than for the high conductive. Combination of a PEM and a gravel layer showed increased infiltrations, and the effects of PEM and gravel layer seemed to be additive. Profile analysis showed a tendency to a slightly larger foreshore beach in the area with a PEM, but the difference is within the uncertainty of the estimation, and the statistical basis is poor. Further more it could not be determined that an increase in slope is caused by the PEMs or other natural conditions like nearshore morphology og wave characteristics. It is concluded that PEM can in principle have som effect on beach groundwater flow, but the effect is considered to be small, and no clear evidence for the impact on the profiles are found.

DSC Measurements on DMPC with Pentanol and Hexanole
Internt-fagligt, 2. modul, 2008, id:251
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract
In (Heimburg and Jackson, 2007) Thomas Heimburg and Andrew D. Jackson propose a model /HJ-model) for the heat capacity curves of lipids containing anaesthesia. The model is suggested as an explanation of the so-called Meyer-Overton rule. The aim of this report is to study how well this model corresponds to heat capacity curves, for 1,2-Dimyristoyl-sn-Glycero-3-Phosphocholine (DMPC) membranes containing pentanol or hexanol, measured on the Perkin Elmer Diamond Differential Scanning Calorimeter (DSC) at IMFUFA, Roskilde University Center. Due to several calibration failures and instrumental errors we were unable to produce heat capacity curves that could constitute a decent basis for an evaluation for the model. We would like to stress that this inconclusiveness was in no way due to the model itself.


Speciale, 3. modul, 2008, id:252
Vejleder:Tage Emil Christensen
Findes på RUb:Ja
Abstract
English abstract

Ionic and Electronic Transport Properties of A2BO4-Type Oxides
Speciale, 3. modul, 2008, id:253
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
The oxygen diffusion and electrical conductivity of the K2NiF4-type oxides (formel) are determined from Electrical Conductivity Relaxation experiments. The results are related to models of the defect chemistry determined from measurements of the oxygen non-stoichiometry, deltac as a function of temperature and PO2. Both the ionic diffusion coefficient of the oxide ions and the electrical conductivity increases significantly with increasing amounts of Sr and are strongly dependent on the PO2. For x = 1.1. The strong variations in the diffusion coefficient can not be well explained form the variations of the concentration of oxygen vacancies. The strong decrease of the diffusion coefficient with decreasing PO2 observed for x = 1.1 might be due to association or ordering of oxygen vacancies. Measurements of thermal and chemical expansions are made on the above-mentioned oxides as well as on (formel). The thermal expansions increase with increased Sr content but depends only little on the size of the A-site cation. The chemical expansions are hardly obervable down to PO2s down to (formel) due to small losses of oxygen and small chemical expansion coefficients. From thermogravimetry measurements it was established that the samples are slightly sub-stoichiometric with respect to oxygen and that the oxygen content is very stable at temperatures up to 1000 degrees C. and in PO2 down to (formelt). The higher the Sr content, the more easily does the sample lose oxygen and this might explain the larger thermal expansions of the Sr rich samples.

Thermal expansion of viscous liquids
Speciale, Modul 3. modul, 2008, id:261
Vejleder:Kristine Niss
Findes på RUb:
Abstract
English abstract
The goal was to develop an experimental method that could measure the thermal expansion coefficient independent of any local field assumptions. We have chosen a capacitative method of determining the thermal expansion and measuring the dielectric constant of a viscous liquid near the glass transistion. Our measurements show a response that can be considered to be caused by thermal expansion of the liquid, but due to instability of the sample holder the magnitude of the hermal expansion coefficient can not be trusted. The response measured by our dilatometric method is qualitatively in agreement with the dielectric method proposed by Bauer et al. [2000a,b]. We believe that the dilatometric method used is sensible, and with som adjustments to the equipment, it can be brought to an adequate level of precision to produce a quantitative measure of the thermal expansion coefficient, independent of any local field assumptions. Although, this does depend on the disappearance of a yet undetermined effect, that we believe causes the sample holder expansion to alter when the capacitor is filled with liquid, as opposed to being empty.

Millikans fornemmelse for e.
Refleksion, 1. modul, 2007/2008, id:245
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
On the doorstep to the 20. century the basis of one of the prime areas of physics throughout the century was established, the conception of structure of matter. To this time there was great differences in the views of, on one hand, the atomistic nature of matter and on the other hand, if accepting the atomistic structure, if these elementary particles were indeed the atoms, or if the atom could be divided. In 1897 J.J. Thomsen succeeded in detecting the existence of the elctron and thereby establishing the atomistic structure of matter. J.J. Thomsen even succeeded in showing that these subatomic particles were identical for different matter, which led him to suggest that the elctron was indeede a shared fundamental part, an elementary particle. In the 15-20 years to come science searched for the actual charge of this elementary particle, the "atom of electricity". A great deal of methods and scientist competed in who were able to establish the most acuurate value for the charge. One of these competitors was Robert A. Millikan who happened to be victorious. The method of Millikan will be described in this report and so will the evolutionary scientific process which brought him to the victory through equal amounts of smartness, diligence and chance. The resulting method, the experimental set-up as well as the physic/algebraic manipulations tends to resemble a "miracle". In recent years accusations has been made towards Millikan, that he, in his strive for perfection, has violated the ethic rules of science - acted with misconduct. This report seeks to analyse the grounding and legitimacy of these accusations by comparing the claimed actions of misconduct to the norms of the scientific community. The report concludes that based on the available sources, it is not "beyond any doubt", that Millikan is guilty as charged. On the other hand, it seems that Millikan has indeed acted with misconduct, but not in the way that he is actually accused. Besides taking the credit for his own doings Millikan seems to have made a deal involving him being credited for the work of others. Taking credit for the work of others is just as well an act of scientific misconduct - and one that in no way is regarded as less offensive.


Refleksion, 1, bachelormodul. modul, 2007/2008, id:246
Vejleder:Kristine Niss
Findes på RUb:Ja
Abstract
English abstract
This project deals with the relationship between the mechanical and dielectric properties for supercooled viscoelastic liquids at temperatures above the glass transition temperature TG of liquids. Mechanic and dielectric measurements have been made for the liquids; 1,2 propanediol and methyl m-toluate. It is shown how the measurements differ frrom the basic models; Maxwell and Debye. The relaxation timesT of the liquids are found and it is shown, that the Vogel-Tammann-Fulcher equation is a good description of the relationship between temperature and relaxation time, for both mechanical and dielectric measurements. By using this equation, the glass temperature of the liquids is determined. Moreover the project shows, that the relaxation time of the mechanical measurements are shorter than the dielectric at a given temperature. We have examined whether the liquids obey time-temperature superposition (TTS), for the dielectric as well as the mechanical measurements. In view of this it is shown, that the top of the alpha-relaxation for the mechanical measurements are wider than for the dielectric. The maximum dielectric loss (formel) for 1,2- propanediol is found to be relatively high about 15-19, whereas for methyl m-toluate it is determined to be approximately low, about 1-2. The minimum slope is determined and its association with the maximum dielectric loss of the liquids have been found. Furthermore we estimatem the maximum loss of shear modulus (formel) as a function of minimum slope. It is shown, that there is tendency for liquids with high maximum dielectric loss, to have a numerical minimum slope around 0.5. It has been found, that the same relation between the maximum loss of shear modulus and minimum slope applies. Finally it is shown, that liquids, which obey TTS, has a numerical minimum slope around 0.5 (formel) 0.1.

Opgaveregning og kompetencer i fysik
refleksion, 1 + 3. modul, 2007/2008, id:247
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
This report deals with what in physics didactics often is called typical problems (in this report called text book problems). I.e. that kind of problems that is normaly done during education in physics. The common idea of this kind of problems is, that they primarily is training use of formulas and mathematics. Our gouls is to answer what purpose this kind of problems have. To describe how it can be used to learn physics, we have used the commonly accepted competence description of mathematics, to make a corresponding description of physics. With this description we analyze a number of text book problems, and the answers to them made by som students, to decide what competencies that is trained by doing the problems. Further we construct some problems of another type, to test what competencies that has not been trained.


Internt-fagligt, 2 + 3. modul, 2007/2008, id:248
Vejleder:Tage E. Christensen
Findes på RUb:Ja
Abstract
English abstract
In this project we research, whether or not a planar carbon film and the 3omega-method can be used to measure the denaturational enthalpy of lysozyme. During the course of this work we encountered unforseen problems related to the usage of carbon films in the 3omega-method. It is shown that the gold-carbon junction of certain films to some estenc behaves like a Schottky Diode. Furthermore an annealing-like process is observed, in which the resistance of the carbon films declines at 330K. The effusivity of glycerol is found within a 14% accuracy. This is in all probability is not accurate enough to observe the denaturational enthalpy of lysozyme. The following conclusions are drawn: 1) Carbon films and the 3omega-method cannot at the present time be used to measure the denaturational enthalpy of lysozyme, 2) If however the problems encounted in this project are worked through the 3omega detection technique might eventually be applicable to proteins.


Speciale, 3. modul, 2007/2008, id:249
Vejleder:
Findes på RUb:Ja
Abstract
English abstract


Internt-fagligt, 2. modul, 2007/08, id:242
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract


Internt-fagligt, 2. modul, 2007/08, id:243
Vejleder:Tage Emil Christensen
Findes på RUb:Ja
Abstract
English abstract
The aim of this project is to investigate if there in the high frequency limit exists a relation between the bulk modulus, (formel), and the shear modulus, (formel), in the liquids propyleneglycol, dipropyleneglycol and tripropyleneglycol. Furthermore we wish to determine if this relation is consistent under various temperature conditions. The frequency dependent bulk and skear moduli are measured from which (formel) and (formel) are determined. This is done through a mechanical system xonsisting of a piezoelectric transducer. The transducer is placed in a cryostat, through which temperature conditions can be controlled. Throughout this project the primary focus is on the method for determining the bulk modulus. As a result of the chosen temperature conditions, we have not been able to achieve usable results. Therefore it has not been possible to establish a relation between (formel) and (formel).

Merging af dielektrisk alpha- og beta-relaksation
Internt-fagligt, 2. modul, 2007/08, id:244
Vejleder:Niels Boye Olsen og Kristine Niss
Findes på RUb:Ja
Abstract

Simulation af rekrystallisation - for inhomogent distribuerede kim i aluminium
internt-fagligt, 2. modul, 2007, id:239
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
In this project, the difference in kinetics and structural development, during recrystallization of inhomogenous and homogenous nucleation sites, is examined. The question is answered by simulating an excisting model, the JMAK model for recrystallization, and changing the parameters in the simulation, so that recrystallization of inhomogenous nucleation sites is simulated. The conclusion is, that the nucleation sites is of importance for kinetics and structural development during recrystallization. The maximum of the Sv(Vv) kinetics curve for the inhomogenous nucleation sites is found at Vv=0.41 and Sv=0.17. The equivalent maximum for the homogenously distributed nucleation sites is found at Vv=0.49 and Sv=0.21. Ind addition the Sv(Vv) kinetics curve is found to be translated leftwards. By examination of the histograms for the grain size distributions of inhomogenous and homogenous nucleation sites at full recrystallization it is found, that the inhomogenous nucleation sites result in a larger spread than the homogenous ones. This is also seen in the simulated microstructures.

Pyroelectricity - A new Application for the Piezoelectric Bulk Transducer
Speciale, 3. modul, 2007, id:240
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract
English abstract
This report presents a new experimental technique based on an alternative use of the piezoelectric bulk transducer used at IMFUFA/NSM, RUC. The measurements rely on the pyroelectric effect of the piezoceramic material that compose the spherical hollow tranducer shell. In order to explain and analyze the experimental test results, an analytic model is proposed as a solution to the thermo-electro-mechanical differential equations describing the phenomena in the transducer and what fills the cavity inside. Measurements involving the highly viscous 5-PPE / Santovac 5 liquid are conducted in the temperature range from 248 K to 260 K near the supposed glass transition of the liquid, during which a drastic change in the physical thermodynamic variables is documented for the liquid. The practical test measurements and the theoretical thermo-electro-mechnical equations are compared for a discussion of the potential of the experimental technique and possible improvements before its application in experimental glass physics are proposed; it is concluded that the technique may be an excellent method for measuring the isobaric thermal expansivity, (formel), but at present it needs complementing experiments to decrease the number of independent variables. The report is written in English.

A study of n-alcohol alkyl chain length dependent structural perturbations of unilamellar 1,2-Dimyristoyl-sn-Glycero-3-Phosphocholine (DMPC) vesicles
Speciale, 3. modul, 2007, id:241
Vejleder:Dorthe Posselt (fysik) og Peter Westh (kemi)
Findes på RUb:Ja
Abstract
English abstract
In this report the n-alcohol induced structural changes af unilamellar 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles in the liquid-crystalline (formel) phase are investigated by molecular dynamics simulations (MD) simulations, densitometry and small angle neutron scattering (SANS). There are used three different n-alcohols, 1-hexanol, 1-octanol and 1-dodecanol, ehich have a different alkyl chain length. 1-Hexanol has an alkyl chain length which is almost half as long as that of the DMPC alkyl chains while 1-dodecanol has nearly the same alkyl chain length as the DMPC alkyl chains. The aim is to achieve more information about the structural changes induced by these three n-alcohols and investigate it at different temperatures. There are made MD simulations of a DMPC bilayer with 1-octanol and a DMPC bilayer with 1-dodecanol. Unilamellar DMPC vesicles with 1-hexanol, 1-octanol and 1-dodecanol are investigated with densitometry and SANS in a temperature range going from 30 degrees C to 50 degrees C. The MD simulations show that both 1-octanol and 1-dodenaol are positioned in the bilayer with the hydroxy group in the bilayer headgroup region and with the alkyl chain positioned in the region of the DMPC alkyl chains. Dodecanol is found to increase the order of the DMPC alkyl chains and thereby increase the thickness of the bilayer. This effect is also seen by the relatively good packing properties of 1-dodecanol, which is accompanied by a decrease in molecular volume and a decrease in area per alkyl chain. Octanol does not show as good packing properties as 1-dodecanol, however it increases the order of the neighboring alkyl chains and decreases the area per alkyl chain. The densitometric measurements show that the packing properties increase in the order; 1-hexanol, 1-octanol and 1-dodecanol, at 30 degrees C. The changes in molar volume by transferring an n-alchol from the bulk phase to the bilayer is found to be 5.2 ml/mole for 1-hexanol, -4.3 ml/mole for 1-octanol and - 16.2 ml/mole for 1- dodecanol at 30 degrees C. At a higher temperature the tendency is different and the change in molar volume is found to be - 9.6 ml/mole for 1-hexanol, - 3.2 ml/mole for 1-octanol and -9.3 ml/mole for 1-dodecanol at 45 degrees C. The SANS measurement show that 1-hexanol decrease the bilayer thickness with (formel). There is found an unusual large polydispersity of the vesicles studied with SANS and the radius found for the vesicles, is too low. However systematic changes in the area per alkyl chain, which is calculated from the radius obtained for the unilamellar DMPC vesicles, are found. It is found that all the n-alcohols decrese the area per alkyl chain. Results obtained at 30 degrees C show that (formel). The difference in packing properties between 1-hexanol, 1-octanol and 1-dodecanol decrese with increasing temperature. However the lateral packing properties increase approximately in the order 1-hexanol, 1-octanol and 1-dodecanol independently of the temperature. This difference in the temperature dependence between the spatial and the lateral packing properties must then be explained by changes in the packing properties along the bilayer normal, which are affected by the changes in fluidity of the alkyl chains and thereby the temperature. It seems that an increase in the fluidity cancels the bad packing properties of 1-hexanol along the bilayer normal and decreases the good packing properties of 1-dodecanol alon the bilayer normal.

A characterization of the alcohol-induced structural changes of unilamellar dipalmitoyl-phosphatidylcholine (DPPC) vesicles
speciale, 3. modul, 2006/2007, id:256
Vejleder:Dorthe Posselt (fysik) Peter Westh (kemi)
Findes på RUb:Ja
Abstract
English abstract


Refleksion, 1. modul, 2006/07, id:235
Vejleder:
Findes på RUb:Ja

Anomaliers Rolle i Ratikelfysikkens Udvikling - Med udgangspunkt i neutrinohistorien
Refleksion, 1. modul, 2006/07, id:236
Vejleder:Martin Niss
Findes på RUb:Ja
Abstract
English abstract
The main purpose of this paper is to achieve insight in the reactions towards the anomalies to understand the influence that reactions have upon the development of particle physics with the neutrino history as a turning point. In answering this, a presentation of the philosophers of science Kuhn, Popper and Lakatos is included and the historic span of the discovery of the neutrino in the period of 1900-1980 is described. The theories from the philosophers of science, forms a foundation for our defintion of an anomaly, and they are used in understanding the reactions. We conclude that the reactions to, and the dissolution of anomalies has changed the praxis of normal science in particle physics in the period beheld. This is seen in the chance that the physicists make when they turn from primarily concentrating on describing known particles, to both describing meanwhile focusing on finding new particles.

Self-organized criticality - En kompleks teori?
Refleksion, 1. modul, 2006/07, id:237
Vejleder:Ken Haste Andersen
Findes på RUb:Ja
Abstract
English abstract

Mechanical Spectrum of a Viscous Liquid
speciale, 3. modul, 2006/07, id:238
Vejleder:Jeppe Dyre, fysik og Jesper Larsen, matematik
Findes på RUb:Ja
Abstract
English abstract
The goal of this thesis is to extend the newly developed narrowband picosecond laser ultrasonic technique to measure the acoustic properties of liquids in addition to solids and polymer films. The method covers a frequency window of roughly 1-400GHz and thus bridges a gap in the existing experimental methods. A sample holder to fabricate thin liquid films was constructed, where the liquid is confined between two metal coated substrates. The construction allows for both a Brillouin backscattering measurement as well as the picosecond laser ultrasonic measurement. This provides a cross-check of the results obtained as the two different measurements ususlly overlap in frequency. To validate the method, measurements are first carried out in the prototypical glass-former glycerol and compared to data in the literature. A series of measurements is then performed on the silicon oil (tetramethyl-tetraphenyl-trisiloxane) at temperatures ranging from 210-295K. The acoustic damping dtermined in the ultrasonic measurement on the silicon oil follows a parabola that seems to agree fairly well with the reference point determined by Brillouin scattering. However, the reproducibility of the results remains to be demonstrated. The prevalent method of data analysis of this type of measurement reveals the frequency dependence of the acoustic damping, but assumes a constant sound velocity. In order to analyze the data obtained with acoustically dispersive media (such as viscous liquids), the experiment is modeled mathematically. The sample construction consists of five layers (substrate-metal-liquid-metal-substrate) that are mechnically and thermally coupled. Each layer is modeled by two coupled partial differential equations for the temperature and displacement fields - the so called thermo-(visco)-elastic equations. Boundary conditions are matched at each interface of the inner layers, while the outer layers (two substrates) are assumed semi-infinite. The direct problem, i.e. assuming that the input and all parameters of the model are known, is formulated as a system of ordinary differential equations and solved algebraically. A comparison of model solutions to data is carried out in the frequency domain and shows that the model agrees qualitatively well with the data. Peak positions, widths of the peaks and the relative manitudes of subsequent peaks all agree excellently with the data. It is thus concluded that the model provides a good description of the experiment and can be a platform for a fitting routine to determine the liquid parameters from data.

Bestemmelse af Magnetokalorisk Effekt ved 3w-Metoden
Intern fagligt projekt, 2. modul, 2006, id:224
Vejleder:
Findes på RUb:
Abstract
English abstract
This work investigates the magnetocaloric effect in the lanthanium manganite La0,67Ca0,22Sr0,11MnO3 (formel) by means of the so-called 3w detection technique. The aim is to determine whether the 3w detection technique is suitable for measuring the magnetocaloric effect of certain magnetic materials. An experiment is conducted by subjecting the material to an oscillating magnetic field. The oscillating magnetic field is gererated by applying a voltage to a solenoid. By means of Fourier transformation, the third harmonic is extracted from the output voltage. It is concluded that the magnetocaloric effect cannot be detected in the conducted, due to fact that the resulting third harmonic is too small to be measurable. However, an improved experimental design might make it possible to enhance the signal to a measurable level. In this case, the 3w detection technique has some advantages compared to the usual techniques used for measuring magnetocaloric effect.

Tempus Gnosis, Tiden den fjerde dimension
, . modul, 2006, id:225
Vejleder:Peder Voetman Christiansen
Findes på RUb:
Abstract
English abstract

Neutrino - Kuhn - Hacking
, . modul, 2006, id:226
Vejleder:Anja Skaar Jacobsen
Findes på RUb:
Abstract
English abstract


speciale, 3. modul, 2006, id:231
Vejleder:Karin Beyer
Findes på RUb:
English abstract

Kommunikation i fysikforskning: En alternativ model
Refleksionsprojekt, 1. modul, 2006, id:232
Vejleder:
Findes på RUb:
Abstract


Internt-fagligt, 2. modul, 2006, id:233
Vejleder:
Findes på RUb:Nej
Abstract


Internt-fagligt, 2. modul, 2006, id:234
Vejleder:Niels Boye Olsen
Findes på RUb:
Abstract

Forgasning af grafit med CO2
Speciale, 3. modul, 2006, id:254
Vejleder:Dorthe Posselt (fysik) Jens Spanget-Larsen (kemi)
Findes på RUb:Ja
Abstract
English abstract
Despite extensive research in gasification of carbon materials a number of unsolved problems still exist. In this study gasification of graphite with carbon dioxide are elucidated by quantum and statistical mechanics calculations. The quantum calculations are done by density functional theory (DFT) models B3PW91/6-31 G(d) and B3LYP /6-31 G(d). To obtain a better understanding of the gasification reaction a series of thermal gravimetric analyses (TGA) are carried out. The TGA experiments reveal that the reactivity models used in the investigation describe the gasification conversion and thermal dependency poorly. Due to the insuficient models the identified reaction parameters are influenced by the experimentel procedure and evaluation methods. In use of more avanced reactivity models it is necessary to obtain more experimentel information, otherwise the model will be overparameterized. In the quantum calculation graphite is modelled with phenyl radical. Due to the associated comprehensive computer calculation time it has been impossible to use a complete graphite model. The simple model allows cal and carbon dioxide. These calculations show good agreement with published results of the phenyl radical and carbon dioxide reaction. Additional calculations are carried out with 5-tetracenyl radical as model fro graphite. The study of the oxygen exchange from carbon dioxide to graphite show discrepancy between the theoretical calculation oand the experimentel results. This is ascribed to the simple graphite model. Surprisingly the calculations with the 5-tetracenyl radical as model for graphite show a poorer agreement with the experimentel results than the phenyl radical. In other words, the phenyl radical is apparently a better graphite model than the 5-tetracenyl radical. This contradicts the prevalent perception, that a polycyclic aromatic molecule like the 5-tetracenyl radical is sufficient to describe the reactivity of graphite. And it stress the need for a thorough investigation of the grahite model.


Refleksion, 1. modul, 2006, id:255
Vejleder:
Findes på RUb:Ja
Abstract

Deep State in Silicon with Electrical Impedance Spectroscopy (EIS)
Speciale, 3. modul, 2006, id:257
Vejleder:Petr Viscor
Findes på RUb:ja
Abstract
English abstract
The purpose of this master thesis has been to determine whether Electrical Impedans Spectroscopy can be used for determination of the electrical characteristics of deep states in semiconductors. A test sample of silicon was bombarded with 2 MeV electrons, creating a number of defects with energy levels within the forbiddeen energy gap. This sample was measured using DLTS as a reference in order to be able to compare the results from the EIS measurements and analysis. The necessary semiconductor theory is reviewed and the principles behind creating a reticulated R, C electrical equivalent network model are described. The results from this project show that the EIS method is capable of determining the characteristics of the deep states, provided the density of these is relatively high. At low densities, the method fails, at least with the suggested model. The development work related to the experimental setup, consisting of a 0.001Hz to 1kHz, and 40Hz to 110MHz impedance analyzers, a cryostat covering the temperature range of 90 degrees K and a specialized sample holder are also described.


internt-fagligt, 2. modul, 2006, id:258
Vejleder:
Findes på RUb:ja
Abstract
English abstract
The report is inspired by a former RUC-project that tried to measure the magnetocaloric effect in (formel) with the 3omega-method. It did not succeed. This report shows through an expansions of the method, the experiment and the hypothesis, that there is measurable non-linear signals on both 2nd and 3rd harmonic voltage signal, measured over a coil with a ferromagnetic core. By measuring the harmonic signals in experiments with (formels), with and without a bias on the harmonic voltage signal, a real signal and an imaginary signal is found. The report concludes that everything points at the magnetocaloric effect and hysteresis loss as explanations.

The Catastrophe Controversy: Foundational Aspects
Internt fagligt projekt, 1. modul, 2006, id:297
Vejleder:-
Findes på RUb:Nej


Videnskabsteknisk projekt, 2. modul, 2006, id:299
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
This paper examines how the physicists H.A. Lorentz, A.A. Michelson, D.C. Miller, and P. Ehrenfest considered the ether after the publication of the special theory of relativity by A. Einstein i 1905. This is accomplished through studies of primary and secondary literature from and about the four physicists. A theoretical walkthrough of the relevant ether theories and experiments with focus on their explanations of the Michelson-Morley experiment in 1887 is given. Michelson and Miller, who both were experimental physicists, maintained the ether because of their inability to understand the propagation of light without a medium. In 1926 Miller measured an ether-drift which was denied by most of the physical society at the time. In 1927 Michelson accepted that parts of the principle of relativity had to be correct, but at the same time he hoped to impose relativistic abilities to the ether. Lorentz' was a theoretical physicist and redefined his view on the ether on several occasions. He also tried to implement parts of the principle of relativity in his theory. He distinguishes between the ethers ability as a medium for light propagation and as a reference system for motion and absolute time, which he believed to be the reason for the maintaining the ether. In 1913 Ehrenfest concurred with the theory of Lorentz' but he also acknowledged the principle of relativity. He believed that the ether theory of Lorentz offered the correct explanation because of the fact that no crucial experiment, that could decide between the ether theory of Lorentz and the theory of special relativity, existed in 1913. Conclusively it can be said that it is understandable that Michelson, Lorentz, Ehrenfest and Miller argued on the behalf of the ether by means of acceptable physical reasoning.

Light-Induced Structural Flexibility of Thylakoid Membranes
, . modul, 2005, id:221
Vejleder:Dorthe Posselt og Peter Westh
Findes på RUb:Ja
Abstract
English abstract

Phosphorlipmembraner pertuberet med 1-alkoholer - et SAXA studie
, . modul, 2005, id:222
Vejleder:Dorthe Posselt
Findes på RUb:
Abstract

Fysik i sovjetunionen - og dens filosofiske dogmer
Reflektionsprojekt, . modul, 2005, id:223
Vejleder:Peder Voetmann Christiansen
Findes på RUb:
Abstract


, 2. modul, 2005, id:227
Vejleder:Tage Emil Christensen
Findes på RUb:
Abstract
English abstract
The main issue of this report is to evaluate, if there is an empirical basis for a correlation between the fragility and Poissions ratio for supercooled liquids. The evaluation takes its startingpoint in (Novikov & Sokolov, 2004) and (Novikov et al., 2005) in which claims of such a correlation have been made. Empirical data acquired from litterature as well as data on four selected liquids, which have been experimentally acquired will be included in the evaluation process. The latter data has been determined by measuring the change in capacity as a function of frequency for piezoelectric ceramic-transducers, which produce either a shear or a bulk deformation on the selected liquids. Such measurments have been conducted at different temperatures near the glass temperature of the selected liquids. Based on the obtained empirical data, it will be evaluated whether there is a clear tendency for a greater fragility to correspond with a greater Poissons ratio. However the uncertainties and deviations concerning the empirical data are of such a magnitude, that there is no basis for describing the tendency with an equation. Neither can the tendency be considered generally applicable, since among the selected empirical data are found liqiuds, which systematically deviate from the tendency, among these are polymers and metal alloys.


, . modul, 2005, id:228
Vejleder:Dorthe Posselt (Fysikvejleder) og Peter Westh (Kemivejleder)
Findes på RUb:
Abstract
English abstract

Characterion of silicon semiconductors
, . modul, 2005, id:230
Vejleder:Niels Boye Olsen
Findes på RUb:
English abstract


Refleksion, 1. modul, 2004/05, id:209
Vejleder:Karin Beyer
Findes på RUb:nej
Abstract

Videnskabeligheden af ikke-falsificerbare teorier
refleksion, 1. modul, 2004/05, id:210
Vejleder:Jeppe Dyre
Findes på RUb:Nej
Abstract
English abstract

SEIRA spektroskopi
Internt-fagligt, 2. modul, 2004/05, id:211
Vejleder:Niels Boye Olsen
Findes på RUb:
Abstract
English abstract
In this report we describe the theories for the increased infrared absorption ability of molecules applied to a substrate coated with a thin metal film. This effect is called surface-enhanced infrared absorption (SEIRA). With transmission spectroscopy we experimentally examine the possibilities for documententation of SEIRA for p-NBA applied to a calciumflouride window coated with goldfilms with thicknesses of 4.5 nm, 8 nm and 16 nm. Furthermore we examine the reproducibility of each series. We find that there is an enhancement in the absorption of p-NBA which can be ascribed to a SEIRA effect and that this enhancement is increased with increased gold film thickness. It is concluded that the reproducibility is sufficient for documentation of the enhancement.


Refleksion, 1. modul, 2004/05, id:212
Vejleder:
Findes på RUb:
Abstract
English abstract
This project treats the subject of which skills we find to be realistic and desired for students taking physics on a compulsory high schools level to obtain during a period of studies when working with vibrations in wineglasses. The relevance of these competencies is alsom treated. On this basis a study period was developed and tested on second year students whose ability to gain the desired competencies was evaluated. During the development of the study period we found it desirable and realistic that the students should be able to develop competencies in their frame of thinking, using experiments, reasoning, and modelling from this study period. A number of goals for the students were set in order to evaluate the students gain from the study period. For each of these goals a desirable level of understanding was defined using Blooms taxonomy. By testing the study period we experienced that the student did not quite reach the desired levels of understanding set by our goals. Thus we must conclude that the students did not develop the desired competencies from our study perod. One of the reasons for this could be lack of basic understanding from the students and their problems using mathematics ind a physics context. Also the student experienced problems expressing themselves using the correct terms and symbols. On the basis of this we have learned that in this kind of study period mathematical and communication competencies should also be in focus.


Refleksion, 1. modul, 2004/05, id:213
Vejleder:Peder Voetmann Christiansen
Findes på RUb:
Abstract
English abstract


Refleksion, 1. modul, 2004/05, id:214
Vejleder:Peder Voetmann Christiansen
Findes på RUb:
Abstract
English abstract
This report contains a discussion on determinisme and chance based on an essay by J. Monod "Neccessity and Chance" and two articles by C. S. Peirce "The Doctrin of Neccessity Examined" and "Evolutionary Love". Assuming that Peirces theories are consistent with the Fluktuation-Dissipation theorem it is discussed in contrast to J. Monods naturalphilosophy whether chance or determinisme is rulling. Peirces Phaneroscopy is presented and utilized on the material in question in order to reveal the coherence present. It is concluded that scientific laws are statistical expressions and not absolute truths.

Newtons spand og Machs princip - er inerti absolut eller relativ?
refleksion, 1. modul, 2004/05, id:215
Vejleder:
Findes på RUb:
Abstract

Evaluating the methods of pollen analysis and optically stimulated luminescence in respect of recovering the climate history of a site near Yabroud, Syria.
Speciale, 3. modul, 2004/05, id:216
Vejleder:Tage Christensen (fysik)
Findes på RUb:
Abstract
English abstract
We have made investigations on a site near Yabroud in Syria in order to describe the climate conditions under which the formation of the site has taken place. To do this it is important to consider the process of deposition. We have applied two methods on samples from the site: An older, pollen analysis, and a younger, optically stimulated luminescence (OSL) and we have investigated their applicability at this location. Pollen analysis has not been developed for the Syrian environment and the OSL-measurement method has not previously been used on this location. We have identified a total of 255 pollen and spores stemming from 42 species found in 15 different layers in the profile of the site. These do not represent a well-founded statistical material so we choose to base our conclusion on the pollen from the two layers in which we have found most pollen (111 cm and 711 cm below the baseline). From the distribution of species found in these two layers we conclude that they have been deposited during a warm period. Pollen analysis has proved to be less successful at this location especially because of the limited amount of pollen and because our pollen slides were blurry even after additional refinement. We took ten soil samples down trough the profile that were subjected to OSL analysis. The results of the individual samples are highly credible and this encourages us to believe that the OSL-measurement procedure works well on our samples, even though their ages are relatively high. We get the following results and as seen there in no clear chronology in the distribution of the ages. We do, however, believe that there is a possibility that the samples have been deposited within a relatively short period of time. (Figure) From the investigations made by us and others it is not possible to give a clear explanation of how the site was deposited or of the climate conditions during the time of deposition. The age distribution of our samples (see the figure above) leads us to believe that the profile was deposited during a relatively short period of time. The ages also correspond well to ages estimates obtained by others on material from the site. We assume that the geologists who have previously examined the site are right when they calim that part of the profile is deposited during an interglacial. In respect of our date estimates we conclude that this must have been the Holsteinian.

Minkowski og udviklingen af den specielle relativitetsteori
Refleksionsprojekt, 1. modul, 2004, id:206
Vejleder:
Findes på RUb:Nej
Abstract

Eksperimentets rolle i fysikundervisningen
Refleksionsprojekt, 1. modul, 2004, id:207
Vejleder:
Findes på RUb:Nej
Abstract

Test of the Shoving Model by Flow Event Investigations - development and application of an algorithm for finding first order saddle points
Speciale, 3. modul, 2004, id:208
Vejleder:Johnny Ottesen (matematik) Jeppe Dyre (fysik)
Findes på RUb:Ja
Abstract
English abstract
The purpose of the work reported in this thesis is to test the central assumption of the Shoving Model for the temperature dependence of the viscosity of supercooled liquids, developed at the Institute for Mathematics and Physics at Roskilde University, by performing numerical calculation on a model liquid. The central assumption of the Shoving Model is that the activation energy necessary to make a flow event in supercooled liquids is due to a compression of the surroundings of the rearranging molecules. Therefore the activation energy is only associated with the molecules in the surroundings defined as those which moves less than a certain threshold value during a flow event. The major part of the work done has been the development of an algorithm capable of finding the molecular configurations responsible for the activation energy. These configurations are equivalent to first order saddle points of the energy function of the entire system. Similar a flow event can be described as a transition from one minimum of this function to another. The system used in this work is a bulk binary Lennard-Jones model liquid consisting of 500 molecules in which the energy is given purely by pair interactions. The basic idea behind the algorithm, called Meta Line Drag (Meta LiD), is that a saddle point between the minima in a flow event can be found by making consecutive plane minimisations along the vector connecting the minima on hyperplanes which are perpendicular to this vector. The Meta LiD algorithm is able to find saddle points in 50% of the investigated flow events. The failure of the remaining is mainly due to a disability to handle directions of negative curvature within the minimisation hyperplanes or areas where the eigenvector of the smallest eigenvalue and the vector connecting the two minima in the flow event diverges. By performing energy calculations on the molecular configurations of the saddle points it is found that the majority (75%) of the activation energy is in the surroundings. This supports the central assumption of the Shoving Model, although only partly because the Shoving Model assumes that all of the activation energy is in the surroundings.

Fysiske forklaringer i undervisning
Speciale, 3. modul, 2004, id:198
Vejleder:
Findes på RUb:Ja
Abstract
English abstract
In the present thesis I have intended to investigate explanations in physics and the teaching of physics. It has been my intention to point out som important aspects concerning physical explanations that may prove relevant in the discussion of why it is meaningful generally to teach physics. In order to do this I have been studying the philosophy of science, inparticular Carl G. Hempel, Bas van Fraassen and Nancy Cartwright and their specific views of scientific explanations. I have been able to point out two distinctions related to explanations that I believe are of importance to the teaching of physics and to teh general discussion of why it is important to teach physics. The first distinction stands between nomological esplanations and causal explanations. The other distinction stands between model-related and theory-based explanations on the basis of the terms used by the above three philosophers of science. The distinction between nomological and causal explanations refers to the fact that som explanations operate on a very high level of abstraction ( nomological explanations), whereas others are based on the structure an mechanisms of the phenomenon of interest (causal explanations). The distinction between model-related and theory-based explanations refers to the fact that theory and phenomenon are very closely and deductively related for som explanations (theory-based explanations), while other explanations are in the need for a model of the phenomenon to establish a relation between the theory and the phenomenon (model-related explanations). It is my conception that the attention to these different kinds of explanations are of great importance to the teaching of physics as well as to the discussion of why the teaching of physics is important. On the basis of the distinction between nomological and causale explanations, it will be easier to put more emphasis on teaching the students how to use a method based on abstraction and genereal laws when solving problems. When focusing on the distinctions between model-related and theory-based explanations, it will be easier for the teacher to navigate between the radical conceptions of the relation between theory and nature in general. Based on this, it is my belief that the two distinctions also are of interest to the discusion of why it is important to teach physics. Focusing on what it is possible to learn when working with physical explanations helps making clear that it is possible for the students to learn how to use the nomological method when solving problems and not only the causal method. The distinction between model-related and theory-based explanations points our attention to the fact that through physics, the students are able to get a more differentiated picture of the relation between theory and nature.

Optimering af neutronspredningsudstyr ved Monte Carlo simulering.
Internt-fagligt, 2. modul, 2004, id:199
Vejleder:
Findes på RUb:Ja
Abstract


Refleksionsprojekt, 1. modul, 2004, id:200
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract
English abstract

Kvantemekanikkens filosofiske grundlag
Refleksionsprojekt, 1. modul, 2004, id:201
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

Den kemiske binding
Refleksionsprojekt, 1. modul, 2004, id:202
Vejleder:
Findes på RUb:Ja
Abstract
English abstract

Projektarbejde i fysik i gymnasieskolen
Refleksionsprojekt, 1. modul, 2004, id:203
Vejleder:Albert Paulsen
Findes på RUb:Ja
Abstract


Refleksionsprojekt, 1. modul, 2004, id:204
Vejleder:
Findes på RUb:Ja
Abstract


Speciale, 3. modul, 2004, id:205
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract
English abstract


refleksion, 1. modul, 2004, id:217
Vejleder:
Findes på RUb:Ja
Abstract

Komparativ Analyse af Fiskepopulations Modeller
, . modul, 2004, id:229
Vejleder:Jesper Larsen
Findes på RUb:
Abstract


Frit projekt, 3. modul, 2003, id:190
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract


Internt-fagligt projekt, 2. modul, 2003, id:191
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract


Speciale, 3. modul, 2003, id:192
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract
English abstract


Speciale, 3. modul, 2003, id:193
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract
English abstract
In this thesis results of studies carried out using differential scanning calorimetry and Raman spectroscopy are presented. Using differential scanning calorimetry the effects of KF, KCl, KBr, KI and KSCN on the phase behavior of aqueous solutions of the triblock copolymer Pluronics P85 and the homopolymer poly(propylene oxide) (PPO) are examined. The change in hydrogen bonding network in liquid water with increasing temperature, is examined by Raman spectroscopy. These results are used to examine the structure of hydrogen bonding network of water in aqueous solutions of P85, PPO and salts. These studies shows that KF, KCl and KBr lower the temperature at which the PPO solutions phase separate. In the solution of P85 these salts lower the temperature at which micelle formation starts, the temperature for the transition at which the micelles change from spherical to a rod-like geometry and the temperature at which the solution phase separates. KSCN has the opposite effect as this salt increase these transitions temperatures. KI has only a small effect, and the directions of the effect vary among the different transition temperatures. The order (KF, KCl, KBr, KI and KSCN) in which the salts affect the phase behaviour is identical with the order of the anions in the Hofmeister series. Temperature dependencies of both the OH-stretching band and a signal at low frequencies which is assigned to hydrogen-bond-stretching-vibration from water molecules interacting by hydrogen bonding with four other water molecules are studied in pure liquid water by Raman spectroscopy. The OH-stretching band in the isotropic spectrum is assigned to OH-oscillators from water molecules involved in different degrees of hydrogen bonding. This assignment give cause to dissolve the band into tree populations of OH-oscillators. From this assignment it was found that the amount of fully hydrogen-bonded water molecules decrease with increasing temperature while the amount of partly hydrogen-bonded water molecules increases with increasing temperature. By combining these results with a simple thermodynamic model, the strength of a hydrogen bond in water was calculated. This value of 12 kJ/mol is close to similar values found by other techniques. Studies of the signal at low frequencies show that the intensity decrease with increasing temperature, which is also a consequence of the breaking down of the hydrogen-bonding network. An observed downshift in frequency with increasing temperature is suggested to be due to the thermal expansion of the liquid. A comparison of the results found by differential scanning calorimetry and Raman spectroscopy indicates that the hydration of P85 and PPO only has a minor effect on the water structure. However, Raman spectroscopic measurements show that salts have a great influence on the water structure. KI, KBr, KCl and KSCN is found to have a structure breaking effect on the water, which decrease in strength in the order mentioned, while KF is shown only to have a very little effect on the water structure. These results show that while the order in which the salts affect the phase behaviour of P85 and PPO follows the Hofmeister series, the order is different when it comes to salts effect on the water structure. It is therefore concluded that a more complicated mechanism is needed to explain the effect of salts on the phase behaviour of the polymer solutions.

Fysikkens historie i en almendannende fysikundervisning - eksemplificeret med Millikan Ehrenhaft kontroversen
Speciale, 3. modul, 2003, id:194
Vejleder:Albert Chr. Paulsen
Findes på RUb:Ja
Abstract
English abstract

Dielectric and Shear Mechanical Relaxation in Glass Forming Liquids
Speciale, 3. modul, 2003, id:195
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract
English abstract
The goal of this thesis is to elucidate whether a relation can be established between shear mechanical and dielectric relaxation in glass forming liquids. The starting point is a genralized Debye model, which has been proposed by Dimarzio & Bishop (1974). The DiMarzip-Bishop model is thoroughly analyzed and reformulated in such a way that different unphysical simplifications that have been used earlier, are avoided. New testable qualitative predictions of the DiMarzio-Bishop model are formulated and the model is put in a form where quantitative tests can be made by using only one macroscopic parameter. The DiMarzio-Bishop model is tested by extensive dielectric and shear mechanical measurements on various molecular liquids. The shear mechanical measurements are performed using a transducer that has been deeloped at IMFUFA by Christensen & Olsen (1995). This transducer allows measurements to be made in an exceptionally large frequency range (1mHz-50kHz). The systematic errors and uncertainties of the two measuring methods are analyzed in detail. Furthermore these errors and uncertainties are taken into account in the reformulation and tests of the DiMarzio-Bishop model. It is found that the DiMarzio-Bishop model to a large extend has qualitative agreement with our data and data form the literature, whereas the quantitative agreement is moderate or poor depending on the liquid tested. This suggests that the model is too coarse grained to capture details of the relaxation processes, but that it does in fact capture the fundamentals of the physics involved, and consequently that there is a direct relation between shear mechanical relaxation and dielectric relaxation.


Speciale, 3. modul, 2003, id:196
Vejleder:Jeppe Dyre, fysik Jesper Larsen, matematik
Findes på RUb:Ja
Abstract
English abstract


Speciale, 3. modul, 2003, id:197
Vejleder:Jeppe Dyre, fysik og Stig Andur Petersen, filosofi
Findes på RUb:Ja
Abstract
English abstract
This extended essay integrates a philosphical and a physical treatment of statistical mechanics. The purpose is to give a perspective on the problems in the foundation og statistical mechanics, specifically regarding the possibility of reducing macroscopic level of description to a consequence of the microscopic level of description. Wtih basis in the book Foundations of Complex-system Theories by Sunny Auyang the statistical mechnical methods are described philosophically bythe theory of sciences tgrough a general treatment of many-body system theory. This is done with the intention of clarifying the theoretical treatment of the relationship between the microscopic and the macroscopic descriptions of composite systems. The method is put into perspective by descriptions of Onsagers reciprocal relations and Kubos interpretation of the FD-theorem which are theories for microscopic descriptions of macroscopic irreversible processes. The conclusion is that the microscopic reversibility is consistent with the macroscopic irreversibility through the application of coarsegraining and that the reduction of the macroscopic level to a consequence of the microscopic dynamics is impossible. Ti is added that microscopic descriptions of macroscopically irreversible processes can be approximated not to produce entropy, from which follows that the macroscopic level can be left out or be described as the consequence of the microscopic interpretation of systems. This reduction is done on the account of the concept of entropy.


Refleksionsprojekt, 1. modul, 2002, id:189
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract

Emergens
Refleksionsprojekt, 1. modul, 2002, id:188
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract
English abstract


, 3.. modul, 2002, id:186
Vejleder:Jesper Larsen
Findes på RUb:ja
Abstract


, 3.. modul, 2002, id:187
Vejleder:Dorthe Posselt
Findes på RUb:ja
Abstract

Museumsformidlingen i ny belysning - Brug af konstruktivistiske teorier i museets formidling af naturfag
reflektionsprojekt, 1.. modul, 2002, id:184
Vejleder:Karin Beyer
Findes på RUb:ja
Abstract


Det frie projekt, 3.. modul, 2002, id:185
Vejleder:
Findes på RUb:ja
Abstract


Internt fagligt, 2.. modul, 2002, id:183
Vejleder:Tage Christensen
Findes på RUb:ja
Abstract

Invarians - om anvendelser og anvendelighed
Refleksionsprojekt, 1.. modul, 2002, id:182
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract


, 3. modul, 2002, id:180
Vejleder:Niels Boye Olsen Jesper Larsen Clive Ellegaard (NBI) Ken Haste Andersen (DTU)
Findes på RUb:Ja
Abstract

Lava Dreams
Modelprojekt, . modul, 2002, id:220
Vejleder:Carsten Lunde Petersen
Findes på RUb: Ja
Abstract
English abstract
In the report at hand the two-component flow af a lava-lamp is simulated. The level set approach is being used to handle the free surface and to compute the surface tension to be used in Navier-Stokes equation. The implementation of the level set function in the modules of Femlab, a finite elemts based program, is described. We conclude that the level set approach os well fit to iterate the position of the dynamic surface and to compute its curvature. In the present imolemantation the level set function distributes the surface forces over a broad band in both sides of the free surface. However, the dynamics if the level set function does not secure constant width of the band, which give rise to nonphysical surface forces in i regions where the level set function is being seriously deformed.


, 2+3. modul, 2001, id:181
Vejleder:Dorthe Posselt
Findes på RUb:
Abstract


reflektionsprojekt, 1. modul, 2001, id:179
Vejleder:
Findes på RUb:ja
Abstract

Dielectric relaxation in poly(propylene glycol) oligomers of increasing chain length
, 3. modul, 2001, id:177
Vejleder:
Findes på RUb:ja
Abstract
English abstract
The dielectric spectra of PPG of 9 different molecular weights have been measured. The dielectric spectra showed both a, b and a` relaxation peaks. In addition a small b` peak was discovered. The spectra were well described by a viscoelastic model, developed on grounds of the generalized BEL model. The temperature dependence of the a relaxation peak intensity were well described by the Debye model. The a relaxation time were well desribed by the shoving model. The b relaxation were successfully modeled by a two level potential well model. The a` peak appeared for molecular weights above a certain molecular weight (Mw*) attributed to the polymer limit. For weights below Mw* the behavior were small molecule-like, with the a relaxation involving the relaxation of the entire molecule. For higher molecular weights the a' peak was attributed to the longest normal mode, described by the Rouse model. No entanglement behavior was seen for the molecular weights studied, ranging from 58 g/mol to 4000 g/mol.

Koblingen mellem de termiske og mekaniske responsfunktioner ved glasovergangen.
, 3. modul, 2001, id:178
Vejleder:Tage Emil Christensen
Findes på RUb:
Abstract
English abstract
Supercooled liquids have the property that through continued cooling they will reach a temperture where their behaviour will change from liquidlike to solidlike behaviour - This phenomenon is called the glass transition. The temperture range around the glass transition is characterised by the fact that the physical properties of the material become frequency dependent, because the characteristic times of the relaxation processes in the material become comparable to the times of the experiments. Through an experimental investigation of the heat capacity and mechanical modulus of 1,2,4-butanetriol an attempt is made to describe the connection between the frequency dependent response functions in the thermal and mechanical domain. The experimental data are compared with two existing models of coupling between the respons functions. The first model can not give a full description of the experimental results, but the possibility of making a final conclusion about the model is decreased by the ability of the liquid to absorb water from the surrounding air. This absorption leads to a big change in the glass transition temperture. The second model has a fundamental problem in explaining the experimental data, which can not be explained by the absorption of water. This means that this model can not explain the connection between the thermic and mechanical response functions near the glass transition.

Billeddannelse af hjernen - principper og anvendelser
reflektionsprojekt, 1. modul, 2001, id:173
Vejleder:Peder Voetmann Christiansen
Findes på RUb:ja
Abstract
Projektet omhandler principper for og anvendelser af fysiske teknikker i form af CT, PET, MRI og fMRI inden for billeddiagnostik og hjerneforskning.

Low-Temperature ac Conductivity of disordered non-metals
Internt fagligt projekt, 3.. modul, 2001, id:175
Vejleder:Jeppe C. Dyre
Findes på RUb:ja
Abstract
English abstract
The random site no barrier (RSNB) hopping model consists of random site energies and Miller-Abrahams transition rates. Particle interactions are disregarded and jumps are only nearest neighboyr. At low temperatures the model can equally well describe ion- and electron transport. The RSNB model is investigated in the one-dimensional case. The model is only solvable through approximative methods. First the analytic effective medium approximation (EMA) is trested. Various asymmetric EMA mothods are analyzed, among them tho only one at the present time that incorporates the RSNB model as its main target. I extend this method to the low-temperature limit, where the result equals that of low-temperature limit random barrier EMA. This is the expected result, since the effective charge transport of the RSNB model at low-temperatures is expected to consist of transport between few low-energy sites, and movement between these sites resembles over-barrier jumps with spatial disorder. According to computer simulations on a N = 1024 lattice, the RSNB model with box distributed site energies converges towards a single curve in the low-temperature limit. The curve is compared to the EMA low-temperature prediction, which resembles that of low-temperature random barrier EMA. The result is not nearly as close to EMA as seen for random barrier simulations.


Speciale i fysik og kemi, . modul, 2001, id:176
Vejleder:
Findes på RUb:ja
Abstract
English abstract
This thesis contains investigations of the aggregation behavior of an ethylene oxide (EO), propylene oxide (PO), ethylene oxide (EO) triblock copolymer, P94, with the composion (EO)28(PO)48(EO)28. P94 has been studied in solutions of the chaotropic (water structure breaker) salt KSCN, and the cosmotropic (water structure builder) salt KF. The methods used are small angle x-ray scattering, capillary vicometry and rheology. A model has been constructed for the relationship between the macroscopic rheological properties and the microscopic interactions between P94 micelles, by assuming a simple repulsive exponential potential. The rheological measurements show that the transition temperatures for the hard gel phase, are shifted to higher temperatures, when KSCN is added to the solution. When KF is added, the same transition temperature is shifted to lower temperatures. These results are in accordance with the salts position in the so-called Hofmeister-series. Meassurements also show that both salts shift the critical gel concentration to P94 higher concentrations. Meassurements with a capillary viscometer show that the intrinsic viscosity is lowered when salts are added. This indicates taht these micelles have a more compact structure than in pure water. SAXS meassurements show that the aggregation number (number of inumers per micelle), is larger when KF is added to the solution, but smaller when KSCN is added. Scattering data also show that the estimated radius of the micelles is larger when KF added. The radius is a little smaller when KSCN is added, but the difference in radii between the micelles in a solution of KSCN and a solution without salt is very small. The model calculations make it possible to calculate the potential between the micelles, in the three types of solutions. When KSCN is added, the potential is higher at longer ranges, but the lope is smaller than the micelles in the solution without salt. When KF is added the potential at long ranges is smaller, but the lope is steeper. Meassurements indicate that when KF is added to a P94 solution, the micelles become more compact and their extension in water gets smaller. When KSCN is added, the picture is less clear. Meassurements show on one side that micelles are becomming more compact, but also that they have a longer range of extension in the solution. Thus the picture is not so clear with respect to the effect of KSCN.


internt fagligt projekt, 3. modul, 2001, id:172
Vejleder:
Findes på RUb:ja
Abstract
English abstract
In the master theis we have investigated two methods for accelerating molecular dynamics simulations of viscous liquids. We have described the methods bias potential dynamics (hyper dynamics) and temperature accelerated dynamics. We have estimated the gain in calculation time. These estimates show that the methods may not be useful in large unordered systems. We have written a program that can be used to simulate a viscous model liquid. We have added a bias potential in order to accelerate the dynamics of the liquid. Unfortunatly we found that our bias potential accelerates the dynamics too irregulary to be useful.

Strukturelt og termodynamisk studie af phospho(C13)lipiddobbeltlag omkring hovedfaseovergangen
internt fagligt projekt, 3. modul, 2001, id:171
Vejleder:Dorthe Posselt
Findes på RUb:ja
Abstract
English abstract
This report is a master thsis in physics, handed in by Kim Bruno Andersen in January 2001. The work presented in this thesis has been conducted at the Department of Mathematics and Physics and the Department og life Sciences and Chemistry, at the University of Roskilde. The main focus of this thesis is the thermodynamical and structual properties of phospholipid membranes, and in particular the anomalous swelling phenomenon, which is observed in multi lamella vesicles, on the high temperature side of the main phase transition. These subjects have been studied in fully hydrated and semi-dry systems, by means of partial water vapour pressure measurements (IPPM) and small angle x-ray scattering measurements (SAXS). Of the experimental work, the dominant part has consisted in finding ways of preparing lipid samples, with a well defined lipid to water ratio, for the SAXS experiments in particular. And preparation methods that ensures an isotropic sample, in general. One of the key features in this subject, is a large number of frees-thaw circles. In reference to anomalous swelling, it is found that the lipid membrane it self, is responsible for some of the awelling, and there is found indications of that the rest of the swelling, is due to an increase in the membrane separation. Swelling in the membrane separation is supported by work of Korremann et al.(B). It have also been observed that reducing the hydration level, greatly reduces undulations of the soft thermal fluctuating membrane. Finally it is shown that hydration of the phospholipid membrane, close to full hydration and at room temperature, is enthalpic unfavourable and entropicaly favoured.

Arisk fysik
Meta-projekt, 2. modul, 2000, id:153
Vejleder:Peder Voetmann Christensen
Findes på RUb:Ja
Abstract


reflektionsprojekt, 1.. modul, 2000, id:170
Vejleder:Peder Voetmann Christiansen
Findes på RUb:ja
Abstract


Frit projekt, 3.. modul, 2000, id:169
Vejleder:Petr Viscor
Findes på RUb:ja
Abstract


Internt fagligt projekt, 2.. modul, 2000, id:168
Vejleder:Dorthe Posselt
Findes på RUb:ja
Abstract


Speciale, 2.. modul, 2000, id:167
Vejleder:ekstern: Kjeld Schaumburg, prof., CISMI, Kemisk Institut, KU. Intern: Niels Boye Olsen
Findes på RUb:ja
Abstract

Meso-scale eddies in the Nordic Seas - Spatiotemporal variability and their relation to deep-sea convection investigated by use of Lagrangian surface drifters
Anvender-tonings projekt kombineret med geografi, 3. modul, 2000, id:166
Vejleder:Tage Christensen Peter Frederiksen
Findes på RUb:ja
English abstract
Properties of meso-scale eddies (1-100km) in the Icelandic, Norwegian, anf Greenland seas are investigated using trajectories of satellite tracked surface drifters released during 1991-1995 within the SACLANTCEN and ESOP programmes. The data set comprises 35.000 buoy days and allows the separation of the seasonal mean circulation and the meso-scale eddies. Their context is investigated through the structure and variability of the surface circulation. We find barotropic currents driven by the Icelandic atmospheric low to be important with a corresponding winter intensification of most of the internal circulation. The regional distribution of the size of the eddies scales approximately with three times the Rossby radius of deformation ( ,\ 1) as derived from climatological hydrographic data by Chelton et al. [1998]. We argue that significant variability in the radii are present due to winterly breakdown of stratification caused by convection in the Greenland Sea and possibly north of Iceland. High levels of eddy kinetic energy are found in the regions of strong current shear associated with topographic obstacles and especially in the frontal regions separating the Atlantic and Artic domains. Individual drifter tracks in the Greenland Sea are studied to indentify meso-scale eddy structures associated with deep reaching convection. We provide an example of an eddy formed by baroclinic instability at the rim of a convected cold patch reported at depth in the winter of 1994 by Lherminier et al. [1999]. This patch is additionally traced at surface in this data set which lead us to conclude that the use of surface drifters combined with additionally data, can be use to investigate convectional events.

Materialeanalyse ved RF Impedansspektroskopi
Eksperimentelt Anvender-toning, 2. modul, 2000, id:163
Vejleder:Petr Viscor
Findes på RUb:ja
Abstract

I EPR-paradokset kan antagelsen af lokalitet bevares ved antagelse af symmetrisk tid
Meta-projekt, . modul, 2000, id:164
Vejleder:Peder Voetmann Christiansen
Findes på RUb:ja

Hvirvelforskning - en storm i et glas vand
Formidlings-toningsprojekt kombineret med komm., 3. modul, 2000, id:165
Vejleder:Karin Beyer, fysikvejleder Oluf Danielsen, Kommunikationsvejleder
Findes på RUb:ja
English abstract


META-projekt, 1. modul, 2000, id:162
Vejleder:Niels Boye Olsen
Findes på RUb:ja
Abstract

Om realiteten af ikke direkte observerbare objekter i fysikken
META-projekt, 2. modul, 2000, id:161
Vejleder:Peder Voetmann Christiansen
Findes på RUb:ja
Abstract

Reaktiviteten for Hvedehalm
eksperimentelt toning-anvender projekt, 2. modul, 2000, id:156
Vejleder:Dorthe Posselt
Findes på RUb:ja
Abstract


Speciale, 3. modul, 2000, id:160
Vejleder:Tage Christensen
Findes på RUb:

Illustrationens kraft - Visuel formidling af fysik
Speciale, Toning-formidling, 3. modul, 1999, id:143
Vejleder:
IMFUFA-tekst: 364
Findes på RUb:Ja
Abstract

Det hydrauliske spring - Et eksperimentelt studie af polygoner og hastighedsprofiler
Speciale, Intern-faglig, eksperimentelt, 3. modul, 1999, id:147
Vejleder:
IMFUFA-tekst: 374
Findes på RUb:Ja
Abstract


A-tonningsprojekt, 1. modul, 1999, id:146
Vejleder:
Findes på RUb:Ja
Abstract

TID - et metafysisk projekt
Meta-projekt, 1. modul, 1999, id:148
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Nej
Abstract


Tonning-anvender projekt, 2 og 3. modul, 1999, id:150
Vejleder:
Findes på RUb:Ja
Abstract

Sorte Kasser
Metaprojekt, 1. modul, 1999, id:149
Vejleder:Peder Voetmann Christiansen og Petr Viscor
Findes på RUb:Ja
Abstract


Speciale, F-tonning, 3. modul, 1999, id:151
Vejleder:Karin Beyer, fysik Magnus Dahl, psykologi
Findes på RUb:Ja
Abstract

Begrundelsesproblematikken i fysikfaget set i et historisk perspektiv
Speciale, 3. modul, 1999, id:152
Vejleder:Karin Beyer
Findes på RUb:Ja
English abstract

Eksperimenter og dannelse i fysik
toningsprojekt, 1. modul, 1999, id:158
Vejleder:
Findes på RUb:ja
Abstract


Internt fagligt projekt, 2. modul, 1999, id:159
Vejleder:Tage Emil Christensen
Findes på RUb:ja
Abstract


internt fagligt + toning-anvender projekt, 2. modul, 1999, id:157
Vejleder:Tage Emil Christensen
Findes på RUb:ja
Abstract

Hvad matematikken og fysikken gjorde for vektorregningen
META-projekt kombineret med matematik, 1. modul, 1999, id:154
Vejleder:Carsten Lunde Petersen, Matematik Jeppe Dyre, Fysik
Findes på RUb:ja
Abstract

Proteinfoldning - Om fysikkens rolle i biologi
META-projekt, 1+2. modul, 1999, id:155
Vejleder:Dorthe Posselt
Findes på RUb:ja
Abstract


Internt fagligt projekt, 1. modul, 1999, id:295
Vejleder:
Findes på RUb:Ja
Abstract


Tonning-Anvender, 1. modul, 1998, id:137
Vejleder:Petr Viscor
Findes på RUb:


Metaprojekt, 3. modul, 1998, id:139
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract

Schottky-barrieren analyseret med Elektrisk Impedans Spektroskopi
Speciale, 3. modul, 1998, id:138
Vejleder:Petr Viscor
Findes på RUb:Ja
Abstract

Bestemmelse af chlorobenzens dipolmoment
, 2. modul, 1998, id:140
Vejleder:
Findes på RUb:Ja
Abstract

Salt og cellemembraner
Internt fagligt projekt, 2. modul, 1998, id:141
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract

Salt i saaret?
Speciale, meta, 3. modul, 1998, id:142
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract

Kauzmann-paradokset
Internt-fagligt projekt, 2.. modul, 1998, id:144
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract

Symmetri i fysik
Meta-projekt, 1. modul, 1998, id:145
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 360
Findes på RUb:Ja
Abstract

Ledning gennem siliciumoxid
Internt-fagligt projekt, 3. modul, 1997, id:124
Vejleder:Petr Viscor
Findes på RUb:Nej
Abstract

Kvantesemiotik
Speciale, meta, 3. modul, 1997, id:125
Vejleder:Peder Voetmann Christensen og Tage Christensen
Findes på RUb:Nej
Abstract

En indledende sammeligning af den Normalvidenskabelige og den Metafysiske Tilgang til Begreberne Kosmogoni, Evolution og Emergens
Metaprojekt, 1. modul, 1997, id:126
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

En asymmetrisk hopmodel for ac-ledning i uordnede faste stoffer
Internt-fagligt projekt, 3. modul, 1997, id:128
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract


Internt-fagligt projekt, 1. modul, 1997, id:127
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract


Intent-fagligt projekt, 2. modul, 1997, id:129
Vejleder:Petr Viscor
Findes på RUb:Ja
Abstract


Speciale, Metabinding, 3. modul, 1997, id:131
Vejleder:
Findes på RUb:Ja


Internt-fagligt eksperimentelt projekt, 3. modul, 1997, id:130
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract

Analogier i fysik
Metaprojekt, 1. modul, 1997, id:132
Vejleder:Jeppe Dyre
Findes på RUb:Nej
Abstract


Metaprojekt, 1. modul, 1997, id:133
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract

Fasebestemmelse af fosfolipider
Tonning-anvender projekt, 1. modul, 1997, id:135
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract

Salte i DMPC dobbeltlag
Internt-fagligt projekt, 2. modul, 1997, id:136
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract

Bragg-linse
Speciale, 3. modul, 1996, id:111
Vejleder:Niels Boye Olsen
Findes på RUb:

Produktion af kolde Natrium klynger
Speciale, 3. modul, 1996, id:110
Vejleder:
Findes på RUb:

Den symmetriske hop-model for AC-ledning i uordnede faste stoffer
Speciale, internt-fagligt, 3. modul, 1996, id:112
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract

Plasmaoscillation i natriumklynger
Speciale, internt-fagligt, eksperimentelt, 3. modul, 1996, id:113
Vejleder:Jeppe Dyre
IMFUFA-tekst: 316
Findes på RUb:Ja
Abstract

Entropiens universalitet
Meta-projekt, 1. modul, 1996, id:114
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

Ledning gennem SiO2
Internt-fagligt projekt, 1 og 2. modul, 1996, id:116
Vejleder:Petr Viscor
Findes på RUb:Ja
Abstract


Metaprojekt, . modul, 1996, id:119
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract

Niels Bohrs periodiske system?
Metaprojekt, 1. modul, 1996, id:118
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract


Speciale, internt-fagligt, 3. modul, 1996, id:117
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract


F-tonningsprojekt, 2. modul, 1996, id:122
Vejleder:Albert C. Paulsen
Findes på RUb:Ja
Abstract

Bulkmoduler
Tonning-anvender projekt, . modul, 1996, id:121
Vejleder:Niels Boye Olsen
Findes på RUb:

Kvantisering af nanolederes elektriske ledningsevne
Tonning-anvender projekt, 1. modul, 1996, id:120
Vejleder:Tage Christensen
IMFUFA-tekst: 338
Findes på RUb:Ja
Abstract


Internt-fagligt projekt, 3. modul, 1996, id:115
Vejleder:Niels Boye Olsen
Findes på RUb:Nej
Abstract


Internt-fagligt projekt, 1. modul, 1996, id:123
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract


Reflektionsprojekt, 1. modul, 1996, id:296
Vejleder:Peder Voetman Christiansen
Findes på RUb:Ja
Abstract

Stoffets mindstedele
Metaprojekt, 1. modul, 1995/96, id:109
Vejleder:
Findes på RUb:Ja
Abstract


Internt-fagligt eksperimentelt projekt, 1. modul, 1995/96, id:108
Vejleder:Christine Papadakis
Findes på RUb:Ja
Abstract

Rejsen til tidens indre - udarbejdelse af et manuskript til en fjernsynsudsendelse
Speciale, F-tonning, 3. modul, 1995, id:106
Vejleder:Peder Voetmann Christiansen (fysik) Bruno Ingemann (kommunikation
IMFUFA-tekst: 315a og b
Findes på RUb:Ja
Abstract

Visuel Mekanik
Tonning-formidling projekt, 2. modul, 1995, id:107
Vejleder:A. C. Paulsen
Findes på RUb:Nej
Abstract

Anomal swelling af lipide dobbeltlag
Speciale, 3. modul, 1995, id:105
Vejleder:Dorthe Posselt
IMFUFA-tekst: 332
Findes på RUb:Nej
Abstract


projekt, tonning-anvender, 3. modul, 1995, id:102
Vejleder:Petr Viscor
Findes på RUb:Ja
Abstract


Metaprojekt, 1. modul, 1995, id:101
Vejleder:Jeppe Dyre og Peder Voetmann Christiansen
IMFUFA-tekst: 298
Findes på RUb:Ja
Abstract


Speciale, 3. modul, 1995, id:104
Vejleder:
Findes på RUb:


Anvenderprojekt, 1. modul, 1995, id:103
Vejleder:Tage E. Christensen
Findes på RUb:Ja
Abstract

Metaforer i fysikken
Metaprojekt, 1. modul, 1995, id:100
Vejleder:Peder Voetmann Christiansen og Petr Viscor
Findes på RUb:Ja
Abstract

Compton Effekt - Historisk og Naturvidenskabsteoretisk
Metaprojekt, 1. modul, 1995, id:99
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

Anvendelse af fysik i matematik: Statistisk mekanik og knudepolynomier
, . modul, 1995, id:86
Vejleder:Dorthe Posselt
Findes på RUb:

Den justerbare piezokeramiske transducer
Tonning-anvender, 1 + 2. modul, 1995, id:94
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract

Universets udvidelse
Metaprojekt, 1. modul, 1995, id:95
Vejleder:Ib Lundgaard Rasmussen
IMFUFA-tekst: 294
Findes på RUb:Ja
Abstract

Masterlignings-modeller af glasovergangen. Termisk-Mekanisk Relaksation
Speciale, 3. modul, 1995, id:96
Vejleder:
Findes på RUb:Ja
Abstract


Speciale, internt-fagligt, 3. modul, 1995, id:98
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract

Characterization of Tetraaza-AC8 - A surfactant with Cation Complexing Potential
Speciale, 3. modul, 1995, id:97
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract


, . modul, 1994, id:85
Vejleder:Niels Boye Olsen
Findes på RUb:


Eksperimentelt A-tonning, 2. modul, 1994, id:84
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract


Tonning-anvender, 2. modul, 1994, id:87
Vejleder:Niels Boye Olsen og Petr Viscor
Findes på RUb:Ja
Abstract

Paradokser i kvantemekanikken
Metaprojekt, 1. modul, 1994, id:90
Vejleder:Jeppe Dyre
Findes på RUb:Ja
Abstract

System i rodet
Speciale, 3. modul, 1994, id:89
Vejleder:Jeppe Dyre
Findes på RUb:

Tradition og fornyelse - Det praktiske elevarbejde i gymnasiets fysikundervisning, 1907-1988
Speciale, 3. modul, 1994, id:88
Vejleder:Karin Beyer og Nils Hybel
IMFUFA-tekst: 272
Findes på RUb:Ja
Abstract


Metaprojekt, 1. modul, 1994, id:92
Vejleder:
Findes på RUb:Ja
Abstract

Intellektuel stil i henholdsvis matematik, fysik og kemi.
F-tonning, 2. modul, 1994, id:91
Vejleder:
Findes på RUb:Ja
Abstract


Internt-fagligt, 2. modul, 1994, id:93
Vejleder:Niels Boye Olsen
Findes på RUb:Ja
Abstract

Modellering af dispersion i piezoelektriske keramikker
, . modul, 1993, id:74
Vejleder:Tage Christensen
IMFUFA-tekst: 257
Findes på RUb:
Abstract


, . modul, 1993, id:76
Vejleder:Niels Boye Olsen
Findes på RUb:

Et udviklingstrin i Elasticitetsteoriens historie i et metafysisk perspektiv
Metaprojekt, 1. modul, 1993, id:75
Vejleder:Tage Christensen
Findes på RUb:Ja
Abstract


, 1. modul, 1993, id:77
Vejleder:Albert C. Paulsen
Findes på RUb:Ja
Abstract


, . modul, 1993, id:78
Vejleder:Peder Voetmann Christiansen
Findes på RUb:

Kommensurabilitets-oscillationer i laterale supergitre
Speciale, 3. modul, 1993, id:79
Vejleder:Rafael Taboryski, Poul Erik Lindelof og Peder Voetmann Christiansen
IMFUFA-tekst: 266
Findes på RUb:Ja
Abstract

Pluronics
, . modul, 1993, id:83
Vejleder:Dorthe Posselt
Findes på RUb:


, . modul, 1993, id:82
Vejleder:Niels Boye Olsen
Findes på RUb:
Abstract


F-toning, . modul, 1993, id:81
Vejleder:
IMFUFA-tekst: 277
Findes på RUb:Ja
Abstract

Dimensionsanalyse - en introduktion
Metaprojekt, 1. modul, 1993, id:80
Vejleder:
IMFUFA-tekst: 269
Findes på RUb:Ja
Abstract


, . modul, 1993, id:73
Vejleder:Niels Boye Olsen og Petr Viscor
IMFUFA-tekst: 245a + b
Findes på RUb:Ja
Abstract

Tankeeksperimenter i fysikken
, 1. modul, 1992, id:72
Vejleder:Dorthe Posselt
IMFUFA-tekst: 243
Findes på RUb:
Abstract

1- og 2-dimensionale strukturmodeller for kvasikrystaller
, 2. modul, 1992, id:71
Vejleder:Dorthe Posselt Lars Kadison
Findes på RUb:
Abstract


Metaprojekt, . modul, 1992, id:70
Vejleder:Dorthe Posselt
IMFUFA-tekst: 232
Findes på RUb:Ja
Abstract

Rum og Tid I Vores Erkendelser - belyst ved to universmodeller
Breddeprojekt, 1. modul, 1992, id:69
Vejleder:Dorthe Posselt
Findes på RUb:Ja
Abstract

Computersimulering og fysik
Metaprojekt, 1. modul, 1992, id:68
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 227
Findes på RUb:Ja
Abstract

Geometri og Virkelighed
, 1. modul, 1992, id:67
Vejleder:Stig Andur Pedersen/Gestur Olafsson og Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

Introduktion til kvante Hall effekten
, 2. modul, 1992, id:66
Vejleder:Peder Voetmann Christiansen og Erland Brun Hansen
IMFUFA-tekst: 236a+b
Findes på RUb:Ja
Abstract

Overfladestruktur og poreudvikling af koks
, 3. modul, 1992, id:65
Vejleder:Peder Voetmann Christiansen
Findes på RUb:Ja
Abstract

Helium - Atomet
, 2. modul, 1991/2, id:64
Vejleder:Petr Viscor
Findes på RUb:

Superledning i gymnasiet
, 2. modul, 1991/2, id:63
Vejleder:Albert Paulsen
Findes på RUb:

Superledning i gymnasiet
, 2. modul, 1991/2, id:62
Vejleder:Karin Beyer
Findes på RUb:

Germaniumbeamanalyse samt A - GE tyndfilms elektriske egenskaber
Speciale, 3. modul, 1991, id:61
Vejleder:Petr Viscor
IMFUFA-tekst: 206 a+b
Findes på RUb:Ja
Abstract

Erkendelse og Kvantemekanik
Breddeprojekt, 1. modul, 1991, id:60
Vejleder:Petr Viscor og Peder Voetmann Christiansen
IMFUFA-tekst: 204
Findes på RUb:Ja
Abstract


, 3. modul, 1991, id:59
Vejleder:Petr Viscor
Findes på RUb:Ja
Abstract


, 2. modul, 1991, id:58
Vejleder:Karin Beyer
Findes på RUb:


, 2. modul, 1990, id:57
Vejleder:Petr Viscor Niels Boye Olsen
Findes på RUb:Ja
Abstract


, 1. modul, 1990, id:56
Vejleder:Petr Viscor
IMFUFA-tekst: 216
Findes på RUb:Ja
Abstract


Breddeprojekt, 1. modul, 1990, id:55
Vejleder:Petr Viscor og Hans Hedal
IMFUFA-tekst: 214
Findes på RUb:Ja
Abstract


, 2 modul. modul, 1990, id:54
Vejleder:Petr Viscor og Ole Bakander
IMFUFA-tekst: 201
Findes på RUb:Ja
Abstract

Metal-Isolator-Metal systemer
Speciale, 3. modul, 1990, id:53
Vejleder:Petr Viscor
IMFUFA-tekst: 198
Findes på RUb:Ja
Abstract


, 2. modul, 1990, id:52
Vejleder:Petr Viscor
Findes på RUb:

Response i Tidsbilledet og Frekvensbilledet
, 2. modul, 1990, id:51
Vejleder:Petr Viscor og Jan Vedde
Findes på RUb:
Abstract

Kaosteoriens paradigmatiske og videnskabsteoretiske position
Breddeprojekt, 1. modul, 1990, id:50
Vejleder:Peder Voetmann Christiansen
Findes på RUb:
Abstract
Ingen rapport


, 2. modul, 1990, id:49
Vejleder:Karin Beyer og Albert Paulsen
Findes på RUb:


Breddeprojekt, 1. modul, 1990, id:48
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 196
Findes på RUb:Ja
Abstract

Deterministisk kaos
, 2. modul, 1990, id:45
Vejleder:Peder Voetmann Christiansen og Karin Beyer
IMFUFA-tekst: 194a
Findes på RUb:Ja
Abstract


, 2. modul, 1990, id:46
Vejleder:Peder Voetmann Christiansen og Karin Beyer
IMFUFA-tekst: 194b
Findes på RUb:Ja
Abstract


, 1. modul, 1990, id:47
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 195
Findes på RUb:Ja
Abstract


Del af et speciale, . modul, 1989, id:40
Vejleder:Peder Voetmann Christiansen og Karin Beyer
IMFUFA-tekst: 179a
Findes på RUb:Ja
Abstract

Elevhefte: Noter til et eksperimentelt kursus om kaos
Del af et speciale, . modul, 1989, id:41
Vejleder:Peder Voetmann Chrstiansen og Karin Beyer
IMFUFA-tekst: 179b
Findes på RUb:Ja
Abstract

Elektrodynamik og relativitetsteori
, 2. modul, 1989, id:43
Vejleder:Peder Voetmann Christiansen og Jeppe Dyre
Findes på RUb:


, 1. modul, 1989, id:44
Vejleder:
Findes på RUb:

Fysik og virkelighed
, 1-2. modul, 1988, id:33
Vejleder:PVC og ACP
Findes på RUb:

Elektronik-kredse i undervisningen
, 1. modul, 1988, id:34
Vejleder:
Findes på RUb:


, 1. modul, 1988, id:35
Vejleder:Niels Boye Olsen
Findes på RUb:

Magnetisk susceptibilitet
, 2. modul, 1988, id:36
Vejleder:Niels Boye Olsen
Findes på RUb:Ja

Overfladen af planeten Mars
Speciale, . modul, 1988, id:37
Vejleder:Jens Martin Knudsen
IMFUFA-tekst: 168
Findes på RUb:Ja
English abstract

Fysik og Virkelighed - kvantemekanikkens grundlagsproblem i gymnasiet
, . modul, 1988, id:38
Vejleder:Albert Chr. Paulsen og Peder Voetmann Christiansen
IMFUFA-tekst: 172
Findes på RUb:Ja
Abstract


, 2. modul, 1988, id:39
Vejleder:Peder Voetmann Christiansen og Niels Boye Olsen
Findes på RUb:


, 1. modul, 1987, id:28
Vejleder:
Findes på RUb:


, . modul, 1987, id:29
Vejleder:
IMFUFA-tekst: 136
Findes på RUb:Ja
Abstract

Chips i undervisningen
, 1. modul, 1987, id:30
Vejleder:
Findes på RUb:

Piezoelektriske krystallers egenskaber
, 1. modul, 1987, id:31
Vejleder:Niels Boye Olsen
Findes på RUb:

Bestemmelse af bulkresistiviteten i silicium
Speciale, . modul, 1987, id:32
Vejleder:Niels Boye Olsen og Petr Viscor
IMFUFA-tekst: 146
Findes på RUb:Ja
Abstract

uvby,beta-systemet - en effektiv fotometrisk spektralklassifikation af B-, A- og F-stjerner
Internt fagligt projekt, 2. modul, 1986, id:300
Vejleder:Ekstern vejleder Helge Kastrup
IMFUFA-tekst: 125
Findes på RUb:Ja
Abstract

Naturvidenskab og dannelse
, 2. modul, 1986, id:21
Vejleder:Karin beyer
Findes på RUb:

uvby,beta-systemet - en effektiv fotometrisk spektralklassifikation af B-, A- og F-stjerner
, 1. modul, 1986, id:22
Vejleder:Helge Kastrup
IMFUFA-tekst: 125
Findes på RUb:Ja

Om udviklingen af den specielle relativitetsteori
, 1. modul, 1986, id:23
Vejleder:Karin Beyer og Stig Andur Pedersen
IMFUFA-tekst: 126
Findes på RUb:Ja


, . modul, 1986, id:24
Vejleder:
IMFUFA-tekst: 131
Findes på RUb:Ja
Abstract

Fysik og Dannelse
, 2. modul, 1986, id:25
Vejleder:
IMFUFA-tekst: 132
Findes på RUb:Ja
Abstract

Computernes fysik
, 1. modul, 1986, id:26
Vejleder:
Findes på RUb:

Fotoelektrisk Hb - fotometri
, 1. modul, 1986, id:27
Vejleder:HKO
Findes på RUb:

Kvanteteori for gymnasiet
, 2. modul, 1985, id:17
Vejleder:Torsten Meyer
IMFUFA-tekst: 92
Findes på RUb:Ja

Aspekter ved kraftvarmeforsyning
Speciale, . modul, 1985, id:18
Vejleder:
IMFUFA-tekst: 96
Findes på RUb:Ja


, . modul, 1985, id:19
Vejleder:
IMFUFA-tekst: 103
Findes på RUb:Ja


, . modul, 1985, id:20
Vejleder:
IMFUFA-tekst: 112
Findes på RUb:Ja


, 2. modul, 1984, id:14
Vejleder:
IMFUFA-tekst: 74
Findes på RUb:Ja


Speciale, . modul, 1984, id:15
Vejleder:Niels Boye Olsen
IMFUFA-tekst: 78
Findes på RUb:Ja


Speciale, . modul, 1984, id:16
Vejleder:Niels Boye Olsen
IMFUFA-tekst: 81
Findes på RUb:Ja

Aspect eksperimentet - skjulte variable i kvantemekanikken ?
Speciale, . modul, 1983, id:11
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 57
Findes på RUb:Ja


, . modul, 1983, id:12
Vejleder:
IMFUFA-tekst: 61
Findes på RUb:Ja


Speciale, . modul, 1983, id:13
Vejleder:
IMFUFA-tekst: 73
Findes på RUb:Ja

Herslev - muligheder for vedvarende energi i en landsby
, 2. modul, 1982, id:10
Vejleder:
IMFUFA-tekst: 50
Findes på RUb:Ja

Til en historieteori om naturerkendelse, teknologi og samfund
, . modul, 1981, id:6
Vejleder:Stig Andur Pedersen, Helge Kragh og Ib Thiersen
IMFUFA-tekst: 38
Findes på RUb:Ja
Abstract


, 2. modul, 1981, id:7
Vejleder:
IMFUFA-tekst: 40
Findes på RUb:Ja
Abstract


, 2. modul, 1981, id:8
Vejleder:
IMFUFA-tekst: 44
Findes på RUb:Ja
Abstract

Eksemplarisk undervisning og fysisk erkendelse - illustreret ved to eksempler
Speciale, . modul, 1981, id:9
Vejleder:
IMFUFA-tekst: 46
Findes på RUb:Ja

Dielektrisk relaxation
, . modul, 1980, id:4
Vejleder:Niels Boye Olsen
IMFUFA-tekst: 28
Findes på RUb:Ja

Polymere stoffers viskoelastiske egenskaber
Speciale, . modul, 1980, id:5
Vejleder:Niels Boye Olsen og Peder Voetmann Christiansen
IMFUFA-tekst: 32
Findes på RUb:Ja

Kaos i fysiske systemer
Speciale, . modul, 1980, id:42
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 180
Findes på RUb:Ja
Abstract

Termodynamik i Gymnasiet
, 2. modul, 1979, id:1
Vejleder:Karin Beyer og Peder Voetmann Christiansen
IMFUFA-tekst: 10
Findes på RUb:Ja


, . modul, 1979, id:2
Vejleder:Albert Paulsen
IMFUFA-tekst: 13
Findes på RUb:Ja


Speciale, . modul, 1979, id:3
Vejleder:Peder Voetmann Christiansen
IMFUFA-tekst: 15
Findes på RUb:Ja


Internt-fagligt projekt, 2. modul, 197, id:134
Vejleder:
IMFUFA-tekst: 346
Findes på RUb:Ja
Abstract

Korrespondensprincippet og Bohrs periodiske system
, . modul, , id:174
Vejleder:Jeppe C. Dyre
Findes på RUb:
Abstract


, . modul, , id:0
Vejleder:
Findes på RUb:

Database opslag den: 20-08-2017