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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Centrum trvale udržitelného rozvoje / Place of Sustainable Development

Tománek, Martin January 2009 (has links)
This work is about sustainability design. I design low energy skyscaper in ostrava. This building is 80m hight.
262

On Stability and Evolution of Solutions in General Relativity

Taylor, Stephen M. 19 July 2007 (has links) (PDF)
This thesis is concerned with several problems in general relativity and low energy string theory that are pertinent to the time evolution of the gravitational field. We present a formulation of the Einstein field equations in terms of variational techniques borrowed from geometric analysis. These equations yield the evolution equations for the Cauchy problems of both general relativity and low energy string theory. We then proceed to investigate the evolutionary linear stability of Schwarzschild-like solutions in higher dimensional relativity called black strings. These objects are determined to be linearly unstable. This motivates a further stability analysis of the charged p-brane solutions of low energy string theory. We show that one can eliminate linear instabilities in p-branes for sufficiently large values of charge. We also consider the characteristic problem of general relativistic magnetohydrodynamics (GRMHD). We compute the eigenvalues and eigenvectors of GRMHD and establish degeneracy conditions. Finally, we consider the initial value problem for axisymmetric GRMHD. We formulate the general Einstein and MHD equations under the assumption of a stationary axisymmetric spacetime without assuming the circularity condition.
263

Energy comparison of wireless data transfer in an energy critical driven system : Digitizing analog meters for the world of IoT - An energy study in a concrete environment

Kantis, Simon, Magnusson, Eric January 2022 (has links)
Digitizing analog meters into the IoT where meters can be read remotely is a solution which is both environmentally and economically beneficial. This study investigate show energy critical systems can gain a longer lifespan by optimizing their energy consumption. The purpose of this study is to evaluate the energy consumption of energy critical systems with different wireless data transfer protocols. This is conducted with experiments and observations.The data was collected by setting up two testbeds where the wireless transmission interfaces WiFi and BLE were used to send data between two microcomputers. These testbeds measured the energy consumption when altering with the variables of the two transmission protocols.The result shows that the internal protocols of WiFi were greatly affected by the changes made in the variables compared to BLE during the experiments. The results also show that when calibrating the different variables, the energy consumption is reduced by up around 52%. Furthermore, the result indicates that there is energy to saveif you optimize transmission power to a specific environment.In this study, BLE has little to no change to the energy consumption when changing the different variables. When investigating the internal protocols of WiFi, they are greatly affected by the different variables being changed. A lower transmission power can be more energy efficient but at the cost of shorter range and eventually a higher packet loss.
264

Trajectory-based analyses of ultrafast strong field phenomena

Ortmann, Lisa 20 December 2019 (has links)
Semiclassical theories have proven to be a versatile tool in ultrafast strong field science. In this thesis, the power of classical trajectory Monte Carlo (CTMC) and quantum trajectory Monte Carlo (QTMC) simulations is celebrated by applying them in various strong field ionization settings. One question to be addressed concerns the way nonadiabaticity in the ionization process manifests itself. It will be shown how the assumption of a vanishing initial longitudinal momentum is the reason for the strong broadening of the initial time spread claimed in a popular nonadiabatic theory. Moreover, it will become clear how the broader time spread of this theory and the non-zero initial longitudinal momenta of another widely applied nonadiabatic theory approximately compensate each other during propagation for typically studied nonadiabatic parameters. However, parameters in the nonadiabatic but still experimentally relevant regime will be found where this approximation breaks down and the two different theories lead to distinguishably different momentum distributions at the detector after all, thus allowing to test which theory describes the situation at the tunnel exit more accurately. After having tunneled through the barrier formed by the laser and Coulomb poten-tial, the electron does not necessarily leave the atom for good but can be captured in a Rydberg state. A study of the intensity-dependence of the Rydberg yield will reveal, among other things, nonadiabatic effects that can be used as an independent test of nonadiabaticity in strong field ionization. Moreover, it will be shown that the duration of the laser pulse can be used to control both the yield and principal quantum number distribution of Rydberg atoms. The highly enhanced and spatially inhomogeneous fields close to a nanostructure are another setting in which atoms can be ionized. Here, the emergence of a prominent higher energy structure (HES) in the spectrum of photoelectrons will be reported. The narrow time-window in which the corresponding electrons are released suggests a promising method for creating a localized source of electron pulses of attosecond duration using tabletop laser technology. Having such potential applications in mind, analytical expressions are derived to describe the electrons’ motion in the inhomogeneous field, thus being able to control the spectral position and width of the HES. Moreover, a unifying theory will be developed in which the recently reported experimental finding of a low-energy peak (LEP) can be understood to arise due to the same mechanism as the theoretically predicted HES, despite those two effects having been found in different energy regimes so far. This unifying theory will show how the well-established experimental technique in which the LEP was reported, i.e. ionization directly from the nanotip rather than from atoms in its vicinity, should allow the realization of a prominent and narrow peak at higher energies as it was theoretically described in the framework of the HES. Despite being much weaker, the spatial inhomogeneity of the Coulomb potential can influence the photoelectron spectrum as well. It will be shown how the asymmetric Coulomb potential of a tilted diatomic molecule introduces an asymmetry in the photoelectron momentum distribution at the detector. The degree of asymmetry depends on whether the electron is born at the up- or downfield atom. This information is then used to quantify the ratio of ionization from the up- and downfield site from experimental photoelectron momentum distributions.
265

Trajectory-based analyses of ultrafast strong field phenomena

Ortmann, Lisa 30 November 2023 (has links)
Semiclassical theories have proven to be a versatile tool in ultrafast strong field science. In this thesis, the power of classical trajectory Monte Carlo (CTMC) and quantum trajectory Monte Carlo (QTMC) simulations is celebrated by applying them in various strong field ionization settings. One question to be addressed concerns the way nonadiabaticity in the ionization process manifests itself. It will be shown how the assumption of a vanishing initial longitudinal momentum is the reason for the strong broadening of the initial time spread claimed in a popular nonadiabatic theory. Moreover, it will become clear how the broader time spread of this theory and the non-zero initial longitudinal momenta of another widely applied nonadiabatic theory approximately compensate each other during propagation for typically studied nonadiabatic parameters. However, parameters in the nonadiabatic but still experimentally relevant regime will be found where this approximation breaks down and the two different theories lead to distinguishably different momentum distributions at the detector after all, thus allowing to test which theory describes the situation at the tunnel exit more accurately. After having tunneled through the barrier formed by the laser and Coulomb poten-tial, the electron does not necessarily leave the atom for good but can be captured in a Rydberg state. A study of the intensity-dependence of the Rydberg yield will reveal, among other things, nonadiabatic effects that can be used as an independent test of nonadiabaticity in strong field ionization. Moreover, it will be shown that the duration of the laser pulse can be used to control both the yield and principal quantum number distribution of Rydberg atoms. The highly enhanced and spatially inhomogeneous fields close to a nanostructure are another setting in which atoms can be ionized. Here, the emergence of a prominent higher energy structure (HES) in the spectrum of photoelectrons will be reported. The narrow time-window in which the corresponding electrons are released suggests a promising method for creating a localized source of electron pulses of attosecond duration using tabletop laser technology. Having such potential applications in mind, analytical expressions are derived to describe the electrons’ motion in the inhomogeneous field, thus being able to control the spectral position and width of the HES. Moreover, a unifying theory will be developed in which the recently reported experimental finding of a low-energy peak (LEP) can be understood to arise due to the same mechanism as the theoretically predicted HES, despite those two effects having been found in different energy regimes so far. This unifying theory will show how the well-established experimental technique in which the LEP was reported, i.e. ionization directly from the nanotip rather than from atoms in its vicinity, should allow the realization of a prominent and narrow peak at higher energies as it was theoretically described in the framework of the HES. Despite being much weaker, the spatial inhomogeneity of the Coulomb potential can influence the photoelectron spectrum as well. It will be shown how the asymmetric Coulomb potential of a tilted diatomic molecule introduces an asymmetry in the photoelectron momentum distribution at the detector. The degree of asymmetry depends on whether the electron is born at the up- or downfield atom. This information is then used to quantify the ratio of ionization from the up- and downfield site from experimental photoelectron momentum distributions.
266

Low-Energy Electron Irradiation Efficiently Inactivates the Gram-Negative Pathogen Rodentibacter pneumotropicus—A New Method for the Generation of Bacterial Vaccines with Increased Efficacy

Fertey, Jasmin, Bayer, Lea, Kähl, Sophie, Haji, Rukiya M., Burger-Kentischer, Anke, Thoma, Martin, Standfest, Bastian, Schönfelder, Jessy, Casado, Javier Portillo, Rögner, Frank-Holm, Baums, Christoph Georg, Grunwald, Thomas, Ulbert, Sebastian 21 April 2023 (has links)
Bacterial pathogens cause severe infections worldwide in livestock and in humans, and antibiotic resistance further increases the importance of prophylactic vaccines. Inactivated bacterial vaccines (bacterins) are usually produced via incubation of the pathogen with chemicals such as formaldehyde, which is time consuming and may cause loss of immunogenicity due to the modification of structural components. We evaluated low-energy electron irradiation (LEEI) as an alternative method to generate a bacterin. Rodentibacter pneumotropicus, an invasive Gram-negative murine pathogen, was inactivated with LEEI and formaldehyde. LEEI resulted in high antigen conservation, and LPS activity was significantly better maintained when compared with formaldehyde treatment. Immunization of mice with LEEI-inactivated R. pneumotropicus elicited a strong immune response with no detectable bacterial burden upon sublethal challenge. The results of this study suggest the inactivation of bacteria with LEEI as an alternative, fast and efficient method to generate bacterial vaccines with increased efficacy.
267

JÄMFÖRELSE MELLAN TRÄREGELVÄGG OCH LÅGENERGI LÄTTBETONGVÄGG : Byggteknik, värmeförmåga och byggekonomi.

Kahachi, Marwan January 2024 (has links)
Commencing with a foundational understanding of the vital role energy modeling plays in optimizing building performance, this study meticulously compares a lowenergy lightweight concrete wall with a wooden stud wall featuring an air gap. The objective is to determine the most advantageous wall type for the construction phase, considering factors such as energy efficiency and cost-effectiveness. Additionally, comprehensive calculations will be performed to assess the heat resistance of each wall type and ascertain the most cost-effective option in terms of heating expenses for residential purposes.Acquiring pertinent information to successfully complete this study, our analysis considers variations in calculations based on whether the lightweight concrete wall is homogeneous or if the wooden stud wall consists of diverse materials.The findings of this study underscore that low-energy lightweight concrete walls offer notable advantages in terms of production aspects, primarily due to cost savings during the construction process. Moreover, in direct comparison to conventional lightweight concrete blocks, the study demonstrates that low-energy blocks outperform wooden stud walls in terms of energy efficiency and consumption.
268

An Enhanced Body Area Network to Wirelessly Monitor Biometric Information

Moore, Levi M. January 2017 (has links)
No description available.
269

ROLE OF CONSTITUENT ELEMENTS IN PROPANE OXIDATION OVER MIXED METAL OXIDES

BHANDARI, RISHABH 13 July 2005 (has links)
No description available.
270

Atomic and Molecular dynamics in intense mid-infrared fields

Zhang, Kaikai 30 December 2015 (has links)
No description available.

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