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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.
1

Integration of in situ and laboratory velocity measurements: analysis and calibration for rock formation characterization

Isham, Randi Jo Lee January 1900 (has links)
Master of Science / Department of Geology / Abdelmoneam Raef / In this study, laboratory measurements of ultrasonic frequency P- and S-wave velocities were collected and analyzed from two sets of cores. The first set is from a near surface study in southeastern Kansas, and the second set was from the deep subsurface and obtained from a newly drilled well (Wellington KGS 1-32) in Sumner County, KS. Ultrasonic velocities acquired from the second set of cores were then compared with in situ sonic and dipole sonic frequencies of P- and S-waves from well logs. Well log data, core data, and ultrasonic velocity measurements were integrated for Gassmann fluid replacement modeling. The understanding of the velocity and elastic moduli variations at ultrasonic frequencies, along with the comparison of well log velocities can potentially provide improved understanding to establish a beneficial calibration relationship. It could also allow for estimation of shear wave velocities for wells lacking dipole sonic log data. The ability to utilize cost-effective ultrasonic measurements of velocities and elastic moduli in the laboratory, for fluid replacement modeling (Gassmann) in CO[subscript]2-sequestration, as well as, enhanced oil recovery (EOR) projects, would be a significant advance. Potential alternative use of ultrasonic velocities for determining the effects of fluid replacement using Gassmann modeling, when log data is lacking, is an ongoing effort. In this study, the fluid replacement modeling is executed based on sonic and dipole sonic P- and S-wave velocities and compared with results from theoretical modeling. The significance of this work lies in the potential of establishing a calibration relationship for the representative lithofacies of the carbon geosequestration target zone of the Wellington KGS 1-32 well in Sumner County, and enabling the use of ultrasonic measurements of body wave velocities and elastic moduli in Gassmann fluid replacement modeling. This work, when integrated with continuing effort in mapping lithofacies of the Arbuckle and Mississippian groups, would potentially be of great importance to fluid flow simulation efforts and time-lapse seismic monitoring. This study will utilize Gassmann modeling and a range of measurements and data, which include: well logs and ultrasonic laboratory P- and S-wave measurements and core analysis data.
2

Laboratory measurements of sound speed and attenuation of water-saturated granular sediments

Argo, Theodore F., 1982- 13 July 2012 (has links)
The propagation of acoustic waves through water-saturated granular sediments has been widely studied, yet existing propagation models can not adequately predict the speed and attenuation of sound across the range of frequencies of interest in underwater acoustics, especially in loosely packed sediments that have been recently disturbed by storms or wave action. Advances in modeling are currently dependent on experimental validation of various components of existing models. To begin to address these deficiencies, three well-controlled laboratory experiments were performed in gravity-settled glass beads and reconstituted sand sediments. Sound speed and attenuation measurements in the 0.5 kHz to 10 kHz range are scarce in the literature, so a resonator method was used to investigate a reconstituted sand sediment in this range. The literature contains laboratory and in situ measurements of sound speed and attenuation at higher frequencies, but existing models can not predict both the speed of sound and attenuation simultaneously in some sediments. A time-of-flight technique was used to determine the speed of sound and attenuation in monodisperse water-saturated glass beads, binary glass bead mixtures, and reconstituted sediment samples in the frequency range 200 kHz to 900 kHz to investigate the effect of sediment inhomogeneity. The effect of porosity, independent of changes in other sediment physical properties, has not been demonstrated in the experimental literature. Therefore, a fluidized bed technique was used to independently vary the porosity of monodisperse glass bead samples from 0.37 to 0.43 and a Fourier phase technique was used to determine the speed and attenuation of sound. Collecting these results together, measured sound speeds showed positive dispersion below 50 kHz while negative dispersion was observed above 200 kHz for some samples. Attenuation measurements showed an approximately f⁰̇⁵ dependence in the low frequency regime and an approximately f³̇⁵ dependence for large-grained samples in the high frequency regime. The laboratory experiments presented in this work demonstrate that both sound speed and attenuation in idealized loosely packed water-saturated sediments can not be simultaneously predicted by existing models within the uncertainties of the model input parameters, but the independent effect of porosity on sound speed can be predicted. / text
3

Influence du changement climatique et des conditions extrêmes sur les massifs fracturés : rôle des fluides (H2O, CO2) dans leur processus d’altération / Influence of climate change and extreme conditions on fractured rock mass : role of fluids (H2O, CO2) in its weathering process

Saad, Alice 21 September 2011 (has links)
L'objectif de ce travail est de comprendre le processus d'altération des calcaires oolithiques et d'estimer leur cinétique d'altération en fonction des conditions climatiques présentes en France. Pour y répondre, des cycles de vieillissement accéléré, basés sur les paramètres issus de l'étude bibliographique et sur les données de température et de précipitations réelles, ont été définis. Ensuite, des lots d'échantillons de deux calcaires oolithiques ont subis ces vieillissements. Les mesures réalisées pour déterminer l'endommagement ont été choisies en fonction de leurs caractéristiques métrologiques et de leur pertinence. Les résultats obtenus ont été comparés avec les mêmes mesures réalisées sur des calcaires altérés de façon naturelle prélevés sur site. Ainsi, les liens entre le processus d'altération des calcaires et les caractéristiques mécaniques, physiques et surtout microstructurales des calcaires ont été établis. Cette analyse a également abouti à des cinétiques d'altération. Les résultats ont été validés par l'étude d'un autre calcaire oolithique sous d'autres conditions climatiques. Enfin, l'influence de changements climatiques éventuels sur les cinétiques d'altération a été déterminée à l'aide d'un outil statistique / The objective of this work is to understand the weathering process of oolitic limestone and estimate their weathering kinetics under French climatic conditions. Accelerated ageing cycles, based on parameters deduced from a literature review and on temperature and precipitation data, have been defined. Then samples of two oolitic limestones have undergone these ageing. The measurements used to determine damage were chosen based on their metrological characteristics and their relevance. The results were compared with the same measurements performed on naturally weathered limestone. Thus, the relationships between the weathering process of oolitic limestone and their mechanical, physical and microstructural characteristics have been established. This analysis also led to weathering kinetics. The results were validated by the study of another oolitic limestone under different climatic conditions. Finally, the influence of a potential climate change on the weathering kinetics was determined using a statistical tool
4

SOUNDS LIKE INTOLERANCE: : A BROADENINGOF HYPERACUSIS EVALUATION

Larsson, William, Sceglova, Tatjana January 2023 (has links)
Hyperacusis is a condition that is described by abnormal reactions to ordinary sounds, however, because of its complexity and newness, this diagnosis still lacks centralized definition and established prevalence rates. Previous research has attempted to define the condition and establish measurements. The Noise Sensitivity Scale (NSS) has been examined several times and new questionnaires have been produced, one being Umeå Hyperacusis Questionnaire (UHQ) produced by Paulin et al. (2019). The latter has not been analyzed in regards to its ability to measure hyperacusis. The current study used exposure data from Paulin et al. (2019) to compare UHQ and NSS abilities to measure the different elements of hyperacusis; the study aimed to a) compare ratings of intensity, concentration, and unpleasantness between UHQ and NSS; b) determine the validity of UHQ. The sample consisted of 64 participants and analyses conducted were linear regression, logistic regression, factor analysis and repeated measures ANOVA. The results indicate that UHQ was greater at measuring intensity, while NSS more accurately measured unpleasantness and concentration. The abilities of the former differed when time was taken in consideration and showed significance in relation to unpleasantness across the lab exposure. The studies suggest that future research should investigate and include more elements that constitute hyperacusis and attempt to increase the sample size. / Hyperacusis är ett tillstånd som karaktäriseras av onormala reaktioner på vanliga ljud, men på grund av att diagnosen är relativt ny och med komplex sjukdomsbild saknas det fortfarande en centraliserad definition och fastställd prevalens. Tidigare forskning har arbetat med att definiera konceptet och utveckla mätinstrument; Noise Sensitivity Scale (NSS) har brukats i flertalet studier och nya enkäter har skapats, bland annat Umeå Hyperacusis Questionnaire (UHQ) av Paulin et al; UHQ har inte analyserats avseende dess förmåga att tillförlitligt mäta hyperacusis. Denna studie använde exponeringsdata från Paulin et al. (2019) för att jämföra UHQ och NSS med avseende på att mäta de olika elementen i hyperacusis. Studien syftade till att a) jämföra självuppskattning av intensitet, koncentration och obehag mellan UHQ och NSS; b) fastställa validitet av UHQ. Urvalet bestod av 64 deltagare och genomförda analyser var linjär regression, logistisk regression, faktoranalys och repeated measures ANOVA. Resultaten visade att UHQ var bättre på att mäta intensitet, medan NSS var lämpligare att mäta obehag och koncentration. UHQs förmåga att mäta obehag skilde sig när tid togs i beaktande och blev då signifikant. Framtida forskning borde undersöka och inkludera fler element som utgör hyperacusis och försöka öka urvalsstorlek.
5

Aplikace osobního větrání ve vzduchotechnice / Application personalized Ventilation in Air Conditioning

Musil, Marek January 2013 (has links)
The subject of this thesis is the application of personalized ventilation in air. The main aim of the work is to construct physical models of artificial ventilation outlets for personal and their experimental verification in the laboratory. The information obtained from experimental measurements are applied in the design of forced personal ventilation to the specified building. Result of this work is to evaluate the use of personalized ventilation for practice with these advantages and disadvantages.
6

Měření na panelu Common-rail / Measurement Panel Common-rail

HART, Petr January 2016 (has links)
This diploma thesis deals with practical measurements on the fuel system of the diesel engine system Common rail. The thesis is divided into tvo basic parts. The first part is theoretical and has the task to familiarize the reader with the history of the diesel injection until after the system Common-rail, where the principle and part of this system will be explained. The second part is focused on the possibility of practical measurement to the fuel system Common-rail on the tutorial panel. Measurement tasks for students will be created on the basis of practical measurements, including the sample assignment, and the elaboration of the form of the protocol. Verification tasks on students and the evaluation of the thesis work will be carried out in the conclusion.
7

Změna parametrů výbojových světelných zdrojů s frekvencí napájecího proudu / Influence of Change in Frequency of the Supply Current to the Operational Parameters of the Discharge Light Sources

Kuptsov, Alexander January 2014 (has links)
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting laboratory experiments the influence of frequency of the supply current on different properties of gas-discharge lamps was described. Besides, simulation of basic electric parameters of high-pressure gas-discharged lamps was implemented in the program SIMULINK/MATLAB. As a result, the received graphs show the dependence of current, voltage and electric power on time. Another simulation included building of dynamic current-voltage characteristics at various frequencies of the supply current. Preparations for the laboratory experiment and the experiment itself were implemented. Compact and tube low-pressure fluorescent lamps were measured. The received graphs show the influence of change in frequency of the current on the operational parameters of the discharge light sources.
8

Experimentální stanovení hydrodynamického zatížení modelu přelévané mostovky / Experimental determination of the hydrodynamic load of the flooded bridge model

Naiser, Dominik January 2020 (has links)
The diploma thesis deals with experimental determination of hydrodynamic load on the overflowed bridge deck model. In the first part of the thesis the author describes the analysis of the problem together with the basic physical laws and principles that are used or assumed in the measurement itself. In the second part the author describes the measurements in the laboratory of the Faculty of Civil Engineering and its gradual processing. At the end of the work are described the results of measurement, their comparison with numerical modeling, other authors and their possible use in practice.
9

Predikce zvukoizolačních vlastností dělicích stavebních konstrukcí a zabezpečení akustické pohody v interiéru budov / PREDICTION SOUND INSULATION PROPERTIES DIVIDER BUILDING STRUCTURES AND SECURITY ACOUSTIC COMFORT INSIDE BUILDINGS

Berková, Petra January 2013 (has links)
This thesis deals with the properties of soundproof partition structures in the low-frequency sound at impact sound insulation and security of acoustic comfort inside buildings. The prediction of impact sound is a simulation laboratory measurements of impact sound. The work is based on the occurrence of frequent complaints of inhabitants of residential homes for subjectively poor impact sound insulation of horizontal dividing structures, whose top layer is formed laminate. Although these structures conform in terms of impact sound insulation in accordance with the requirements of CSN 73 0532: 2010, residents complain about the subjective perception of the sounds of lower frequencies. A noise with a distinctive character of sound at low frequencies has been proved by measuring the spectral analysis and evaluation of sound pressure levels caused by the movement of persons roof construction to the floor. On the measurement and evaluation carried out in accordance with the measurement and evaluation of noise in non-working environment can be related requirement under the Regulation No. 272/2011 Coll. "On the protection of health from the adverse effects of noise and vibration." Occupational noise limits for protected buildings interior space do not apply to noise from ordinary use of the apartment. Under current legislation, the problem is in the Czech Republic at present insoluble. Therefore, this work explores ways evaluation of impact sound and delivery is determined conclusions. With the low-frequency impact sound insulation is also related to the latter part of this dissertation, where the computing program ANSYS (version 14.0) is simulated laboratory measurements of impact sound insulation of the real structure. The paper presents the results of simulation, and the sound pressure level in the receiving room to třetinooktávového band 630 Hz. These results are compared with measured values modeled in the laboratory.
10

Adaptivní kmitočtový filtr / Adaptive frequency filter

Kříž, Petr January 2010 (has links)
The aim of this work is to design a filter of the type low–pass of order 5th with Butterworth’s approximation in the range of over-tuning 10 – 100 kHz and if it will be possible so! achieve even higher marginal frequencies. To compare two typical representatives of the frequency filters cascading and non-cascading synthesis from the viewpoint the accuracy of an! approximation function, sensitivity to the tolerance values of components, number of the components (mainly OZ) and viability, especially the possibility of electronic over-tuning in selected frequency range. On the basis of these conditions will be chosen one design, which will be realized later. Further it will be necessary to consider the possibilities of electronic over-tuning and to choose for this over-tuning suitable component, to design user management changes of marginal frequency fm by the help of keyboard + LCD and control application on the PC. For this hardware will be programmed appropriate control software. At the end of this work will be constructed appropriate device, which fullfils requirements written above and will be subjected to the laboratory measurements that verify function of this device. The constructional details of the filter are presented in the enclosure at the end of this work. At the CD are available all materials, which were created during the master’s thesis or which are necessarily concerned.

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