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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.
281

Optimal Design of Single Factor cDNA Microarray experiments and Mixed Models for Gene Expression Data

Yang, Xiao 12 March 2003 (has links)
Microarray experiments are used to perform gene expression profiling on a large scale. E- and A-optimality of mixed designs was established for experiments with up to 26 different varieties and with the restriction that the number of arrays available is equal to the number of varieties. Because the IBD setting only allows for a single blocking factor (arrays), the search for optimal designs was extended to the Row-Column Design (RCD) setting with blocking factors dye (row) and array (column). Relative efficiencies of these designs were further compared under analysis of variance (ANOVA) models. We also compared the performance of classification analysis for the interwoven loop and the replicated reference designs under four scenarios. The replicated reference design was favored when gene-specific sample variation was large, but the interwoven loop design was preferred for large variation among biological replicates. We applied mixed model methodology to detection and estimation of gene differential expression. For identification of differential gene expression, we favor contrasts which include both variety main effects and variety by gene interactions. In terms of t-statistics for these contrasts, we examined the equivalence between the one- and two-step analyses under both fixed and mixed effects models. We analytically established conditions for equivalence under fixed and mixed models. We investigated the difference of approximation with the two-step analysis in situations where equivalence does not hold. The significant difference between the one- and two-step mixed effects model was further illustrated through Monte Carlo simulation and three case studies. We implemented the one-step analysis for mixed models with the ASREML software. / Ph. D.
282

CALIBRATION OF THE MU2E ABSOLUTE MOMENTUM SCALE USING POSITIVE PION DECAYS TO POSITRON AND ELECTRON NEUTRINO

Xiaobing Shi (18421551) 22 April 2024 (has links)
<p dir="ltr">The Mu2e experiment will search for neutrinoless, coherent conversion of a muon into an</p><p dir="ltr">electron in the field of an aluminum nucleus (μ−N ! e−N) at the sensitivity level of 10−17.</p><p dir="ltr">This conversion process is an example of Charged Lepton Flavor Violation (CLFV), which</p><p dir="ltr">has never been observed experimentally before. The Mu2e experiment tracker is designed</p><p dir="ltr">to accurately detect the 105 MeV/c conversion electron (CE) momentum in a uniform 1 T</p><p dir="ltr">magnetic field. The mono-energetic positrons (e+) at 69.8 MeV from the decay of positively charged</p><p dir="ltr">pions (p+) that have stopped in the aluminum stopping target are investigated as a</p><p dir="ltr">calibration source to measure the accuracy of absolute momentum scale. The backgrounds</p><p dir="ltr">for the calibration arise from μ+ decay-in-flight (DIF) backgrounds and other stopped p+</p><p dir="ltr">decays that produce reconstructed e+ tracks mimicking a signal trajectory originating from</p><p dir="ltr">the stopping target. The most significant background is the μ-DIF background. Therefore,</p><p dir="ltr">we identified the need for a momentum degrader placed at the entry of the Detector Solenoid,</p><p dir="ltr">to increase the pion stops in the stopping target and suppress the μ-DIF background. The</p><p dir="ltr">material of the degrader is chosen to be titanium (Ti). The thickness of degrader is optimized</p><p dir="ltr">by the pion stops efficiency to muon flux efficiency ratio and the 4mm Ti degrader is the</p><p dir="ltr">optimized one. The calibration signal and backgrounds are simulated with the 3mm and</p><p dir="ltr">4mm Ti degrader. The ratio of S/B is used as a figure of merit, S/B ? 1.85 for the 3mm Ti</p><p dir="ltr">degrader and S/B ? 2.93 for the 4mm Ti degrader. The 4mm Ti degrader performs better</p><p dir="ltr">than the 3mm Ti degrader in terms of S/B ratio. By fitting the reconstructed momentum</p><p dir="ltr">spectra of signal and backgrounds, we extract the signal distribution peak and width of</p><p dir="ltr">x0 = 69.268 ± 0.013 MeV/c and ? = 0.324 ± 0.009 MeV/c (with the 3mm Ti degrader),</p><p dir="ltr">x0 = 69.263 ± 0.013 MeV/c and ? = 0.299 ± 0.009 MeV/c (with the 4mm Ti degrader).</p><p dir="ltr">We also show that the peak shifts by backgrounds for both degraders are within 100 keV/c</p><p dir="ltr">momentum scale accuracy requirement.</p>
283

A Taguchi-Based Approach to Tune Bio-Inspired Guidance Systems for Tactical UAVs

Amrite, Shardul 01 February 2022 (has links)
This thesis aims to tune the control parameters of a bio-inspired guidance system designed to confer a tactical behavior to unmanned aerial vehicles (UAVs). This bio-inspired guidance system is capable of reducing exposure to threats, while traversing previously uncharted, and potentially hostile territories. UAVs employing this guidance system may exhibit a more or less tactical behavior by tuning 9 user-defined parameters within specified intervals. Although the UAV's behavior can be easily forecasted whenever all parameters are set to exhibit the most cautious behavior or the most reckless behavior, it is difficult to devise a taxonomy of flight behavior whenever these parameters are not set at the boundaries of their admissible intervals. The scope of this thesis is to analyze and forecast the UAV's behavior as a function of these user-defined parameters. To this goal, the Taguchi analysis method is employed to deduce those parameters that affect the UAV's behavior more than others. Successively, 81 software-in-the-loop simulations have been performed to analyze the UAV's behavior as a function of the most influential user-defined parameters. Finally, 10 flight tests were performed to validate the numerical results. / Master of Science / This thesis aims to tune the control parameters of a bio-inspired guidance system designed to confer a tactical behavior to unmanned aerial vehicles (UAVs). This bio-inspired guidance system is capable of reducing exposure to threats, while traversing previously uncharted, and potentially hostile territories. UAVs employing this guidance system may exhibit a more or less tactical behavior by tuning 9 user-defined parameters within specified intervals. Although the UAV's behavior can be easily forecasted whenever all parameters are set to exhibit the most cautious behavior or the most reckless behavior, it is difficult to devise a taxonomy of flight behavior whenever these parameters are not set at the boundaries of their admissible intervals. The scope of this thesis is to analyze and forecast the UAV's behavior as a function of these user-defined parameters. To this goal, the Taguchi analysis method is employed to deduce those parameters that affect the UAV's behavior more than others. Successively, 81 software-in-the-loop simulations have been performed to analyze the UAV's behavior as a function of the most influential user-defined parameters. Finally, 10 flight tests were performed to validate the numerical results.
284

Valuing the effects of mining critical minerals : The Per Geijer deposit in Kiruna

Krigsman, Olivia January 2024 (has links)
Critical raw materials have become an important part in the green transition, and EU is not self-sufficient to secure the supply EU needs. LKAB recently released that the Per Geijer deposit in Kiruna contains large amounts of some critical raw materials, for example rare earth metals. If a mining permit of the deposit is approved, an additional mine would operate in Kiruna. There are different effects from mining, and some can be difficult to evaluate, since the effects may not hold a market price. Therefore, this study intends to assess effects caused by mining of the Per Geijer deposit in Kiruna. A choice experiment is applied which includes the effects of mining on the attributes; reindeer husbandry, outdoor activities and new job opportunities, together with a cost attribute of a potential municipal tax increase. The result identified a significant negative economic impact on both reindeer husbandry and outdoor activities, but positive on potential job opportunities. As well, men and those working in mine related areas are more willing to choose the ‘approved permit for mining’ option.
285

Use of Chlorosulphonic Acid to Differentiate Hydrocarbon Types

Shown, John 06 1900 (has links)
This study investigates the rate of reaction of various types of hydrocarbons with chlorosulphonic acid at the temperature 10 degrees Celsius.
286

AN INVESTIGATION OF THE PROCESS OF WORD RECOGNITION

Lambert, Ronald Dick 09 1900 (has links)
Two experiments were conducted to examine parameters of the process of word recognition. In both experiments, subjects were required to guess the identity of words from which letters were exposed. In the first experiment, independent variables were frequency of occurrence in the language of stimulus words, number of letters selected from the words, and the position of the letters within the words. All three variables yielded significant effects. Connotative meaning of the stimulus words and the number of letters exposed from the beginning of the words were varied in the second experiment. As in the first experiment, the effect due to number of letters was significant. Connotative meaning, however, did not contribute significantly to subjects’ recognition latencies. / Thesis / Master of Arts (MA)
287

Experiments on vertical gas-liquid pipe flows using ultrafast X-ray tomography

Banowski, M., Beyer, M., Lucas, D., Hoppe, D., Barthel, F. 15 February 2017 (has links) (PDF)
For the qualification and validation of two-phase CFD-models for medium and large-scale industrial applications dedicated experiments providing data with high temporal and spatial resolution are required. Fluid dynamic parameter like gas volume fraction, bubble size distribution, velocity or turbulent kinetic energy should be measured locally. Considering the fact, that the used measurement techniques should not affect the flow characteristics, radiation based tomographic methods are the favourite candidate for such measurements. Here the recently developed ultrafast X-ray tomography, is applied to measure the local and temporal gas volume fraction distribution in a vertical pipe. To obtain the required frame rate a rotating X-ray source by a massless electron beam and a static detector ring are used. Experiments on a vertical pipe are well suited for development and validation of closure models for two-phase flows. While vertical pipe flows are axially symmetrically, the boundary conditions are well defined. The evolution of the flow along the pipe can be investigated as well. This report documents the experiments done for co-current upwards and downwards air-water and steam-water flows as well as for counter-current air-water flows. The details of the setup, measuring technique and data evaluation are given. The report also includes a discussion on selected results obtained and on uncertainties.
288

Využití konopí setého ve výuce chemie / Utilization of Cannabis Sativa in Teaching Chemistry

Stránská, Adéla January 2012 (has links)
The diploma thesis deals with Cannabis sativa. The aim is to focus on possible utilization of Cannabis sativa in teaching chemistry. The theoretical part describes the botany of cannabis, overviews phytocannabinoids, substances contained in cannabis, and it also includes wide use of cannabis in agriculture and industry. The practical part deals with the selection and arrangement of a possible curriculum about chromatography as the most affordable technique for analysis of cannabis at school, including the formulation of school experiment methodology using the thin-layer chromatography of Cannabis sativa extract to demonstrate the presence of phytocannabinoids. The practical part also includes the scheme of an educational project on cannabis and describes the latest techniques, as well as the methodology of work with them, which are suitable for analysis of phytocannabinoids.
289

Fyzika top kvarku v experimentu Atlas / Top Quark Physics with the ATLAS Detector

Slovák, Radim January 2013 (has links)
In the presented diploma thesis we study the reconstruction of the top antitop system in proton-proton colisions with central mass energy 7 TeV de- livered by LHC accelerator at CERN to the ATLAS experiment. ALPGEN and MC@NLO generators are described as two main method of top antitop pairs simulations. We compare events simulated by generators to data from LHC. The background and selection criteria are summarized. Next we de- scribed various methods of the top antitop reconstruction. Finally the Z particle was also studied. 1
290

Experimentální časopis / Experimental Magazine

Kovařík, Jakub January 2012 (has links)
The Material is a line of physical events structured into the form of the magazine. Each event is an attempt to move in the same area in which similar conditions are given, but every time among different range of people. The self-destructive principle of the Material magazine is to return to the same thing and deal with it again and again. It means not to do anything new, do the same all the time as long as all possibilities are exhausted. To exhaust what is given, to squeeze it like a lemon, to resign on the open end. I think of Věra Linhartová, who ehxausted the Czech language by continual experiments. Every new event – a variation better than an issue – returns back to the previous variantions and tries to work with them again. This progression, teamwork, dealing with someone else´s texts and pictures and the object of the printed issue keep the context of the magazine. The Material is the grey area between the psysical thing-object and the event.

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