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Liste over projekter af typen: det Internt-faglige- og anvenderprojekt


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.


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.


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


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

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.


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.


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.

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.


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


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

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.

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


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


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

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.


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.


Internt fagligt projekt, 2.. modul, 2000, id:168
Vejleder:Dorthe Posselt
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

Reaktiviteten for Hvedehalm
eksperimentelt toning-anvender projekt, 2. modul, 2000, id:156
Vejleder:Dorthe Posselt
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


Tonning-anvender projekt, 2 og 3. modul, 1999, id:150
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


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:

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

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

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


Internt-fagligt eksperimentelt projekt, 3. modul, 1997, id:130
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

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

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


Speciale, internt-fagligt, 3. modul, 1996, id:117
Vejleder:Niels Boye Olsen
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


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


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


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

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


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


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


Internt-fagligt, 2. modul, 1994, id:93
Vejleder:Niels Boye Olsen
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


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

Database opslag den: 21-09-2017