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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.
11

Avaliação de mecanismos não convencionais de instabilização de encostas: o papel das poropressões de ar / Evaluation of unconventional mechanisms of slope instabilization: the role of pore-air pressure

Terra, Victor Scartezini 29 August 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-01-30T10:00:16Z No. of bitstreams: 2 Dissertação - Victor Scartezini Terra - 2016.pdf: 3940729 bytes, checksum: 27241c105d696ce18e125b5eb6c44691 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-30T10:04:56Z (GMT) No. of bitstreams: 2 Dissertação - Victor Scartezini Terra - 2016.pdf: 3940729 bytes, checksum: 27241c105d696ce18e125b5eb6c44691 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-30T10:04:56Z (GMT). No. of bitstreams: 2 Dissertação - Victor Scartezini Terra - 2016.pdf: 3940729 bytes, checksum: 27241c105d696ce18e125b5eb6c44691 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Natural disasters related to landslides have caused thousands of deaths and left tens of thousands homeless people around the world. Landslides can occur in most cases due to factors related to water infiltration on soil, causing a raise in the positive pore-water pressure. But what is often observed is that both water infiltration and the reduction of negative pore-water pressure due to water infiltration are not, in practice, enough to justify some of the observed landslides. Some less conventionals mechanisms, such as lightning, are not, usually, taken in consideration in a failure analysis, but can contribute to the factor of safety reduction. This paper aims to study the effects of atmospheric discharges in the stability of natural slopes of residual soils. Partial differential equations governing the coupled flow of pore-water and pore-air are developped. The numerical modeling is made with the FlexPDE software, version 6. The results show that there is a raise on pore-air pressure inside the soil due to atmospheric discharge. However, the raise of pore-air pressure works both in the raise of the apparent cohesion and the reduction on net pressure. It is concluded that any failure due to atmospheric discharge will present a shallow slip surface. / Desastres naturais relacionados a deslizamentos de massas de terra já causaram milhares de mortes e dezenas de milhares de desabrigados no mundo inteiro. Os deslizamentos podem ocorrer em sua maioria devido aos fatores provenientes da infiltração de água no solo, gerando aumento das poropressões positivas de água. Mas o que se observa frequentemente, é que a infiltração e a redução das poropressões negativas muitas vezes não são, na prática, o suficiente para justificar todos os escorregamentos observados. Mecanismos menos convencionais como descargas atmosféricas e o aumento das poropressões de ar consequentes do efeito Lisse normalmente não são levados em consideração em análises de ruptura, mas podem contribuir para a diminuição do fator de segurança de taludes. Esta pesquisa tem como objetivos, portanto, estudar como os efeitos do avanço da frente de infiltração e das descargas atmosféricas irão afetar a estabilidade de taludes em encostas naturais de solos residuais. Além disso, cita-se como objetivos secundários o desenvolvimento de modelos numéricos para análises acopladas de fluxo de água e ar, e a verificação desses modelos por meio de análises de validação. Um estudo detalhado de como a onda de choque e os gradientes de temperatura de descargas atmosféricas se comportam ao atingir a superfície terrestre é desenvolvido para que se possam definir as condições de fronteira do problema. Equações diferenciais parciais acopladas para fluxo de água e ar são desenvolvidas. As análises são feitas com o auxílio do programa FlexPDE, versão 6. Os resultados mostraram que há um aumento das poropressões de ar na massa de solo provenientes de descargas atmosféricas ou do efeito Lisse. No entanto, tais acréscimos de poropressão de ar trabalham tanto a favor do ganho de coesão aparente como como na diminuição das tensões líquidas. No estudo da influência do aumento das poropressões de ar como consequência de descargas atmosféricas conclui-se que eventuais rupturas de taludes causadas por isso serão rasas. Com relação ao estudo do aumento de poropressão de ar em taludes como consequência do efeito Lisse, conclui-se que os acréscimos de poropressão de ar serão maiores na massa de solo quando mais próximo da saturação estiver o solo.
12

Normativa data för samband mellan subglottalt tryck och ljudtrycksnivå

Björklund, Staffan January 2014 (has links)
Syftet med föreliggande studie var att undersöka sambandet mellan subglottalt tryck och ljudtrycksnivå, och undersöka inverkan av kön och tonhöjd. Röststyrkan är starkt beroende av subglottalt tryck och sambandet har analyserats i ett flertal studier, som alla visar på ett linjärt förhållande mellan logaritmen av subglottala trycket och ljudtrycksnivån (SPL). Schutte (1980) analyserade sambandet för 21 kvinnor och  24 män som producerade ett stort antal mätdata med olika SPL och tonhöjd. Tryck mättes med ballong i esofagus. Tanaka & Gould (1982) analyserade 4 kvinnor och 6 män på tre ljudnivåer på bekväm tonhöjd; svag, normal och stark ljudstyrka. Subglottalt tryck uppmättes med pletysmograf, med försökspersonen sittandes i lufttät box. Pressad fonation karaktäriseras av ett högt subglottalt tryck och en förhållandevis låg SPL, så sambandet mellan tryck och SPL torde påverkas av glottal adduktion och troligen också av tonhöjd. Därför borde normativa data från röstfriska personer vara av intresse. I denna studie producerade 16 kvinnor och 15 män sekvenser av stavelsen [pæ] på fyra tonhöjder, jämnt fördelade över en oktav. Regressionsanalys användes för att approximera sambandet mellan SPL och logaritmen av subglottalt tryck samt för att beräkna genomsnittlig SPL-ökning för dubblat subglottalt tryck och beräknad SPL vid 10 cm H2O. Resultatet visar som väntat ett mycket starkt samband mellan subglottalt tryck och ljudtrycksnivån, med en korrelationskoefficient på 0.835 respektive 0.826 för kvinnor respektive män. En fördubbling av subglottalt tryck gav en genomsnittlig SPL-ökning av 11,5 dB (SD 3.8) för kvinnor och 10,0 dB (SD 2,7) för män. Skillnaden mellan kvinnor och män var här signifikant, vilket ger stöd för att använda separativa normativa värden för kvinnor och män. Genomsnittlig beräknad nivå vid 10 cm H2O var 83,6 dB (SD 3,9) för kvinnor och 82,2 dB (SD 4,6) för män beräknat till 15 cm mikrofonavstånd. Sambandet mellan subglottalt tryck och SPL skiljde sig en aning beroende på tonhöjd, men skillnaden var ej signifikant. Trots de relativt höga standardavvikelserna tyder resultatet på att det vore värt att studera i vad mån avvikelser från de potentiellt normativa värdena skulle kunna vara tecken på någon slags fonatorisk dysfunktion. / The purpose of this study was to examine the relationship between subglottal pressure and sound pressure level (SPL), and to study the importance of gender and fundamental frequency in this relationship. Vocal loudness is strongly dependent on subglottal pressure. The relation between them has been analyzed in several investigations, all showing a linear relationship between the SPL and the log of the pressure. For example, Schutte (1980) analyzed the relation in 21 female and 24 male subjects who produced a great number of samples at different degrees of vocal loudness and at the subjects’ preferred pitch. Pressure was measured by means of an esophageal balloon. Tanaka and Gould (1982) analyzed 10 subjects each producing vowels at three loudness levels at comfortable pitch. Pressure data were obtained from a plethysmograph, with the subject sitting in an airtight box. Pressed phonation is characterized by a high subglottal pressure producing a comparatively low SPL, so hence the pressure – SPL relationship would be affected by glottal adduction and possibly also by F0. Therefore normative data from healthy voices should be of interest. In the present study 16 female and 15 male normal voices were asked to produce diminuendo and crescendo sequences of the syllable [pæ] at four pitches, equidistantly spaced within an octave. Trendlines were used to approximate the relation between SPL and the log of subglottal pressure. The resulting regression equations were used to calculate the average SPL increase for doubling of pressure and the SPL produced by a pressure of 10 cm H2O. The results showed an average correlation coefficient of 0.835 and 0.826 for female and male subjects. A doubled pressure produced an SPL increase of 11.5 dB (SD 3.8) and 10.0 dB (SD 2.7) for the female and the male voices. The difference between female and male voices was significant, which supports use of separate normative values for female and male voices. On average, a subglottal pressure of 10 cm H2O produced an SPL @ 0.15 m of 83.6 dB (SD 3.9) and 82.2 dB (SD 4.6) for the female and the male voices. The relationship between subglottal pressure and SPL depended somewhat on fundamental frequency, but the difference was not significant. In spite of the relatively high standard errors the results indicate that it would be worth to study in what extent differences from the potentially normative values of this study may be a sign of some sort of phonatory dysfunction.
13

Vývoj tlakového spínače pro kolejová vozidla / Development of pressure switch for rail vehicles

Havelka, Ondřej January 2016 (has links)
This diploma thesis deals with the design of pneumatic pressure switch with adjustable hysteresis. In the thesis is carried out the introduction in the theory of compressed air and research of the pressure switches at the market. Based on the gathered information and customer specification, the design draft of the pressure switch has been created. In the thesis are described three main parts of the prototype: transform of the pressure, adjustable hysteresis and synchronization of the microswitches. In the end of the thesis is described the testing of prototype and summary of the results.
14

Microplasma micro-ondes en cavité résonnante à la pression atmosphérique : caractérisation et application à la nanostructuration de surface / Microwave microplasma in resonant cavity at atmospheric pressure : characterization and application to the nanostructured surface

Arnoult, Grégory 10 February 2011 (has links)
Dans l’optique d’aller toujours vers le plus petit, un réacteur plasma micro-ondes en cavité résonnante fonctionnant à la pression atmosphérique a été développé à l’Institut Jean-Lamour (IJL, UMR 7198) dans l’équipe ESPRITS (Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces).Ce réacteur plasma présente la particularité de pouvoir fournir une post-décharge de petite dimension (de l’ordre du millimètre). Un mélange Ar-O2 est utilisé comme gaz composant le plasma. L’aspect filamentaire de ce type de plasma est une des caractéristiques majeures du dispositif. De plus, la post-décharge se trouve notamment composée d’oxygène atomique, espèce active très utilisée par exemple en PECVD ou pour la fonctionnalisation de surface.Notre travail a consisté à mettre au point ce réacteur plasma et à caractériser la post-décharge résultante. Après avoir maîtrisé les principaux paramètres pouvant jouer notamment sur la forme de la post-décharge, nous nous sommes intéressés à son utilisation en tant que source plasma pour des applications de traitements de surfaces.Nous avons ainsi étudié des dépôts de films minces de SiOx à partir d’hexaméthyldisiloxane (HMDSO) en utilisant la post-décharge comme source d’oxygène atomique permettant la décomposition du précurseur organosilicié. L’HMDSO est utilisé ici car il est assez simple à manipuler et il a été souvent étudié, nous permettant d’obtenir sur lui de nombreuses informations. Différentes structures auto-organisées sont apparues au sein de ces dépôts et ont été étudiées afin de comprendre leur mécanisme de formation / In order to always go to the smallest, a plasma reactor microwave in resonant cavity operating at atmospheric pressure was developed at the Institut Jean Lamour (IJL, UMR 7198) in the team ESPRITS (Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces).This plasma reactor has the particularity to provide post-discharge of small size (about one millimeter). An Ar-O2 gas is used as the plasma component. The filamentous appearance of this type of plasma is a major feature of the device. Furthermore, the afterglow is notably composed of atomic oxygen, active species such as widely used PECVD or surface functionalization.Our job was to develop the plasma reactor and to characterize the resulting afterglow. After mastering the key parameters that can play on the particular shape of the afterglow, we were interested in its use as a plasma source for surface treatment applications.We studied deposition of SiOx thin films from hexamethyldisiloxane (HMDSO) using post-discharge source of atomic oxygen for the decomposition of the organosilicon precursor. The HMDSO is used here because it is fairly easy to handle and it has often been studied, allowing us to obtain much information on him. Various self-organized structures appeared in these deposits and have been investigated to understand their formation mechanism
15

Meteostanice / Weather Station

Beneděla, Pavel January 2013 (has links)
This thesis deals with conception of proposal and implementation of a weather station. Weather station is composed of three main parts which are measuring station, showing station and USB wireless receiving module. Measuring station measures basic meteorologic variables and sends measured variables through wireless communication. Showing station is designed to present measured data with graphics user interface and generate data for a web server.
16

Approximating Subglottal Pressure from Oral Pressure: A Methodological Study

Frazer, Brittany L. 11 July 2014 (has links)
No description available.
17

Vliv klimatických podmínek na bezdrátové routery / Wireless Routers and Infuence on Climatic Conditions

Martinka, David January 2018 (has links)
This thesis deals with problematics of installing wireless routers into specific locations depending on their heating and ideal signal transmission. The thesis is divided into eight chapters. The beginning of the thesis is theoretical describes the introduction into the problematics, the second part is practical and covers the executed experiment. The theoretical part contains six chapters – heat, signal, wireless router and measured climatic conditions. The practical part describes the executed experiment by thermo-camera which was used to scan wireless routers in IoT Lab in Avast Software company. Based on this experiment, the ideal position for installing the wireless router is then established. The conclusion of the practical part includes an analysis of the results of the questionnaire survey, in which technically skilled people were asked to describe the height of installation of their wireless router or whether did they consider heat and signal propagation while installing their wireless routers.
18

Meteorologická stanice se vzdáleným přístupem / Meteorological Station with Remote Access

Svoboda, Josef January 2010 (has links)
This thesis discusses design and realization of air temperature, pressure and relative humidity measuring device, transmission of measured data over internet and their presentation on a web site. First chapter introduces reader into principles of measuring air temperature, pressure and relative humidity and various types of sensors used for measuring . Next, the conception of designed system is described. Designed system must accomplish tasks from reading raw data from the sensor up to thein graphical presentation to the internet user. Second and third chapter describes hardware and software design of air temperature, pressure and relative humidity measuring unit. In next part one can find description of software used to transmit measured data over internet and software for generating web pages which are shown to users. The work is revieved in the final part of this thesis.
19

Chemical Reaction Dynamics at the Statistical Ensemble and Molecular Frame Limits

Clarkin, OWEN 12 September 2012 (has links)
In this work, experimental and theoretical approaches are applied to the study of chemical reaction dynamics. In Chapter 2, two applications of transition state theory are presented: (1) Application of microcanonical transition state theory to determine the rate constant of dissociation of C2F3I after π∗ ← π excitation. It was found that this reaction has a very fast rate constant and thus is a promising system for testing the statistical assumption of molecular reaction dynamics. (2) A general rate constant expression for the reaction of atoms and molecules at surfaces was derived within the statistical framework of flexible transition state theory. In Chapter 4, a computationally efficient TDDFT approach was found to produce useful potential energy surface landscapes for application to non-adiabatic predissociative dynamics of the molecule CS2 after excitation from the ground state to the singlet C-state. In Chapter 5, ultrafast experimental results of excitation of CS2 to the predissociative neutral singlet C-state is presented. The bandwidth of the excitation laser was carefully tuned to span a two-component scattering resonance with each component differently evolving electronically with respect to excited state character during the quasi-bound oscillation. Scalar time-resolved photoelectron spectra (TRPES) and vector time-resolved photoelectron angular distribution (TRPAD) observables were recorded during the predissociation. The TRPES yield of photoelectrons was found to oscillate with a quantum beat pattern for the photoelectrons corresponding to ionization to the vibrationless cation ground state; this beat pattern was obscured for photoelectron energies corresponding to ionization from the vibrationally excited CS2 cation. The TRPAD data was recorded for two general molecular ensemble cases: with and without a pre-excitation alignment laser pulse. It was found that in the case of ensemble alignment (Chapter 6), the “molecular frame” TRPAD (i.e. TRMFPAD) was able to image the purely valence electronic dynamics of the evolving CS2 C-state. The unaligned ensemble TRPAD observable suffers from excessive orientational averaging and was unable to observe the quantum beat. Engineering efforts were also undertaken to eliminate scattered light background signal (Chapter 7, Appendix A) and improve laser stability as a function of ambient pressure (Appendix B) for TRMFPAD experiments. / Thesis (Ph.D, Chemistry) -- Queen's University, 2012-09-11 22:18:20.89
20

The Aerodynamic, Glottographic, and Acoustic Effects of Clear Speech.

Tahamtan, Mahdi 06 September 2022 (has links)
No description available.

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