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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.
471

Evaluation of the lateral scapular slide test using radiographic imaging : a validity and reliability study

Daniels, Todd P. 06 August 2001 (has links)
Function of the shoulder complex is highly dependent on the relationship between the scapula and the humerus. Etiologies for the disruption of the glenohumeral relationship include impaired or abnormal scapular function, motion, or position. The lateral scapular slide test (LSST) has been developed as a clinical tool to assess this phenomenon, also known as scapular dyskinesis. The primary purpose of this study was to determine the validity of the LSST by comparing the clinical measurements on the skin surface to the actual anatomical distance between the scapula and the spine as seen on radiographic images. The secondary purpose of this study was to determine the intra-rater and inter-rater reliability of the LSST. Nine subjects (18 shoulders) were assessed with the clinical LSST and radiographic images in three test positions (0��, 45��, and 90�� of glenohumeral abduction). Comparison of the clinical LSST measurements with the radiographs revealed the LSST to be valid (>0.80) in only the 0�� and 45�� test positions with respective Pearson correlation values of 0.91 and 0.98. Excellent (>0.75) intra-rater ICC (2,1) reliability (0.91-0.97) was found for all three test positions. Inter-rater ICC (2,1) reliability values were excellent for the 0�� (0.87) and 45�� (0.83) test positions, and fair to good for the 90�� position (0.71). This study demonstrated that the LSST is an accurate and consistent measure of scapular movement and position for the 0�� and 45�� test positions. Clinicians should exercise caution when interpreting measurements obtained at the 90�� test position because the validity and reliability values did not reach established standards. / Graduation date: 2002
472

Essays in efficiency and productivity analysis of economic systems

Zelenyuk, Valentin 07 June 2002 (has links)
In this work I integrate some of my recent research developments in the theory and practice of Productivity and Efficiency Analysis of Economic Systems. In particular, I present some new theoretical relationships between various measures of efficiency and productivity, propose new solutions to some aggregation problems in efficiency analysis and apply the existing theory and the new findings to empirical analysis in Industrial Organization. / Graduation date: 2003
473

Critical heat flux estimation for annular channel geometry

Pagh, Richard T. 26 April 2001 (has links)
Critical Heat Flux (CHF) is an important safety parameter for the design of nuclear reactors. The most commonly used predictive tool for determination of CHF is a look-up table developed using tube data with an average hydraulic test diameter of 8 mm. There exist in the world today nuclear reactors whose geometry is annular, not tubular, and whose hydraulic diameter is significantly smaller than 8 mm. In addition, any sub-channel thermal hydraulic model of fuel assemblies is annular and not tubular. Comparisons were made between this predictive tool and annular correlations developed from test data. These comparisons showed the look-up table over-predicts the CHF values for annular channels, thus questioning its ability to perform correct safety evaluations. Since no better tool exists to predict CHF for annular geometry, an effort was undertaken to produce one. A database of open literature annular CHF values was created as a basis for this new tool. By compiling information from eighteen sources and requiring that the data be inner wall, unilaterally, uniformly heated with no spacers or heat transfer enhancement devices, a database of 1630 experimental values was produced. After a review of the data in the database, a new look-up table was created. A look-up table provides localized control of the prediction to overcome sparseness of data. Using Shepard's Method as the extrapolation technique, a regular mesh look-up table was produced using four main variables: pressure, quality, mass flux, and hydraulic diameter. The root mean square error of this look-up table was found to be 0.8267. However, by fixing the hydraulic diameter locations to the database values, the root mean square error was further reduced to 0.2816. This look-up table can now predict CHF values for annular channels over a wide range of fluid conditions. / Graduation date: 2001
474

A multi method investigation into the costs and into the benefits of measuring intellectual capital assets

Gray, Dina January 2005 (has links)
This study sets out to address the question of whether the costs and the benefits of measuring intellectual capital assets differ depending on the driver for that measure. Although pressure is growing on firms to measure and report on their intellectual capital assets no research has yet been published that questions the costs associated with such actions. And although academic research has purported to show links between the management of intellectual capital assets and real business benefits the research carried out thus far'has not focussed specifically on the benefits of measuring intellectual capital assets. Although there are now a variety of intellectual capital asset measurement frameworks there has been no cross comparison as to which intellectual capital asset measures provide the most business insight or where the outcome of that measurement is most effective. Using a multi method approach the thesis is tested in three phases; an extensive literature review covering intellectual capital, performance measurement and organisational effectiveness; a survey and content analysis to explore what and why companies measure; and structured interviewing of six companies to investigate the costs and the benefits of measurement. The thesis is tested through the investigation of thirteen propositions which show that: firstly, there is a difference in the relative cost of measuring intellectual capital assets given the measurement driver, which is explained by the frequency of measurement, the mode of data collection and analysis, and whether the use of the measure is a by product of some other driver, secondly, that the insight provided by an intellectual capital asset measure differs given the measurement driver, thirdly, that the measurement of intellectual capital assets is most effective for planning the future; and lastly, that particular measurement drivers are effective, to differing degrees, in financial, customer, operational, people and future organisational performance domains.
475

Drivers and purposes of performance measurement : an exploratory study in English local public sector services

Micheli, Pietro 06 1900 (has links)
This dissertation focuses on the interactions between local public sector organisations and institutions in the development of performance measurement (PM) targets and indicators. The research is grounded in the performance measurement and management literature and adopts a joint new institutional and resource dependence perspective. Empirically, the research, which is qualitative and theory-building, consists of case studies undertaken in local public sector organisations in England. The iterative comparison of theory and data has enabled the investigation of a number of relevant themes. In the last decade, the British Government has placed great emphasis on the consistency of objectives, targets and indicators from national to local levels with the aim of enhancing performance, transparency and accountability, and of driving behavior. However, this research shows that the influence of several organizations and the co- existence of various PM initiatives generate confusion and overlaps locally. Moreover, in the cases considered the unmanageable number of indicators and the lack of clarity regarding the drivers and purposes of PM have led to confused massages and counter- productive approaches to the measurement and management of performance. From a theoretical view-point, the favourable comments expressed by interviewees regarding the current PM regime contrast with critics of New Public Management. Furthermore, legitimacy-seeking and efficiency-enhancing rationals have emerged as intertwined and loosely coupled. This is in opposition to what is maintained by early new institutional theorists. In line with resource dependence theory, PM systems were found to be significant components of power systems in organisations. Through the examination of the roles of PM and the investigation of relevant concepts such as 'golden thread' and performance culture, this research aims to make an impact on policy-making and to improve the ways in which targets and indicators are set and used, hence having a positive effect on the services delivered.
476

Measurement of applied stresses using the polarization of Rayleigh surface waves

Junge, Michael Dominic Alexander 01 December 2003 (has links)
No description available.
477

Developments and improvements to the particle-into-liquid-sampler (PILS) and its applications to Asian outflow studies

Ma, Yilin 04 1900 (has links)
No description available.
478

Electrochemical Synthesis of Novel Polyaniline-Montmorillonite Nanocomposites and Corrosion Protection of Steel

Hoang, Van Hung 17 January 2007 (has links) (PDF)
This dissertation describes a new electrochemical synthesis of novel composite materials based on montmorillonite (MMT) clay and intrinsically conducting polyaniline (PANI). PANI was successfully incorporated into MMT galleries to form PANI−MMT nanocomposites. Electropolymerization of anilinium ions which are intercalated inside the clay layers have been carried out at a constant applied potential. The synthetic conditions have been optimized taking into account the effect of concentration of aniline, magnetic stirring and potential cycling. The resulting organic-inorganic hybrid material, PANI-MMT has been characterized by various physicochemical techniques. Results of elemental analysis show that nanocomposite contains only 10 % of conducting PANI. Formation of PANI inside the clay tactoid has been confirmed by the expansion of inter layer distance of MMT as revealed by X-ray diffraction studies. Relatively lower interlayer expansion for PANI-MMT than that of anilinium-MMT indicates the higher stereoregularity in PANI-MMT which has strong influence on electrical properties of nanocomposites. Infrared spectroscopy studies reveal the presence of physicochemical interaction, probably hydrogen bonding, between clay and polyaniline. Cyclic voltammetry studies indicate that presence of electroinactive clay does not influence the electrochemical activity of PANI. Electrochromic behaviour of PANI-MMT nanocomposites have been studied using in situ UV-Vis spectroscopy which reveals that electrochromism of PANI in the composite material has been retained. One of the main technological applications of conducting polymers, particularly PANI, is in the area of corrosion protection of active metals. PANI-MMT nanocomposites synthesized using the present method and a chemically synthesized PANI which is soluble in organic solvents have been used to protect C45 steel surface against corrosion. Corrosion studies have been performed using electrochemical impedance measurements(EIM)and anodic polarization studies. Electrochemical impedance data has been analyzed using a suitable equivalent circuit. Corrosion protection of steel offered by both PANI-MMT and organically soluble PANI is evident form the increase in the value of charge transfer resistance of the coated steel surfaces. Time dependent EIM measurements reveal that charge transfer resistance gradually decreases with time, however, the values are much higher than that of uncoated surfaces. Two capacitive loops, one at higher and another at lower frequencies, observed in the Nyquist plots have been assigned to the electrical properties of coating material (in the present case, PANI-MMT or soluble PANI) and electrochemical process at the interface, respectively. An anodic shift in the corrosion potential, a decrease in the corrosion rate and a significant increase in the polarization resistance indicate a significant anti-corrosion performance of both PANI-MMT nanocomposite and organically soluble PANI deposited on the protected steel surface. / Diese Dissertation beschreibt eine neue elektrochemische Synthese neuartiger Compositmaterialien basierend auf dem Tonmineral Montmorillonite (MMT) und intrinsisch leitfähigem Polyanilin (PANI). Die Elektropolymerisation von Aniliniumionen, welche in die Tonmineralschichten eingebaut sind, wurde bei einem konstanten Potenzial durchgeführt. Das resultierende organisch-anorganische Hybridmaterial PANI-MMT wurde mit verschiedenen physikochemischen Methoden charakterisiert. Die Ergebnisse der Elementaranalyse zeigen, dass nur 10 % des Nanocompositmaterials aus leitfähigem PANI bestehen. Die Vergrößerung des Zwischenschichtabstandes von MMT, die bei Röntgendiffraktometrieuntersuchungen beobachtet wurde, lässt auf die Bildung von PANI innerhalb der Tonmineral-Taktoide schließen. IR-spektroskopische Untersuchungen deuten auf das Vorhandensein von Wechselwirkungen physikochemischer Art, wahrscheinlich Wasserstoffbindungen zwischen dem Tonmineral und Polyanilin, hin. Untersuchungen mit zyklischer Voltammetrie zeigten, dass die Anwesenheit von elektroinaktivem Tonmineral die elektrochemische Aktivität von PANI nicht beeinflusst. Das elektrochrome Verhalten von PANI-MMT Nanocompositen wurde mit UV-Vis-Spektroskopie untersucht, wobei sich herausstellte, dass das elektrochrome Verhalten vom PANI im Compositmaterial erhalten bleibt. Eines der technologischen Hauptanwendungsgebiete von leitfähigen Polymeren, insbesondere von PANI, ist der Korrosionsschutz von aktiven Metallen. PANI-MMT Nanocomposite die mit der angegebenen Methode (elektrochemisch) synthetisiert wurden und chemisch synthetisiertes in organischen Medien lösliches PANI wurden zum Korrosionsschutz von C45 Stahl eingesetzt. Die Korrosionsuntersuchungen wurden mit Hilfe von elektrochemischen Impedanzmessungen (EIM) und anodischen Polarisationsuntersuchungen durchgeführt. Der von PANI-MMT und von in organischen Medien löslichem PANI gebotene Korrosionsschutz ist wahrscheinlich auf die Zunahme des Ladungsdurchtritts widerstandes der beschichteten Stahloberfläche zurückzuführen. Die anodische Verschiebung des Korrosionspotenzials, eine Verringerung der Korrosions-geschwindigkeit und eine deutliche Zunahme des Polarisationswiderstandes sind eindeutige Hinweise für das Antikorrosionsvermögen von PANI-MMT und auch von in organischen Medien löslichem PANI, welche auf der zu schützenden Stahloberfläche abgeschieden wurden.
479

Feasibility study for implementation of automotive measuring method in aerospace industry

Söderblom, Robin, Jonsson, Staffan January 2015 (has links)
This thesis comprises an investigation in order to find possibilities to implement the method used in the automotive industry to automatically generate a collision free measurement program within the aircraft components manufacturer. The purpose with the study was to compare and analyse the different methods used to generate measurement programs at GKN Aerospace Engine Systems in Trollhättan, National Electric Vehicle Sweden (NEVS) and Volvo Cars Corporations (VCC).The study was conducted through meetings, observations and questionnaires with staff from the geometry assurance engineering (GAE) departments and measurement departments in each company. By mapping the virtual GAE process started from concept development in CAD to the measurement phase in which components are measured in coordinated measuring machines (CMM), a chain of activities was analysed.NEVS and VCC are today using RD&T and IPS to generate optimized CMM programs in which a time efficient measurement path can be generated. This method was compared with the current approach at GKN Aerospace where they use one supplier for offline CMM programming (OLP) software solutions and CMMs. They are thereby working in a closed system where the OLP communicates with the CMM by supplier specific methods. The automobile manufacturer NEVS and VCC, in contrast, uses a DMIS protocol which is an ISO and ANSI standard.The study shows that an implementation of the software used by the Swedish automobile manufacture NEVS and VCC at GKN Aerospace in Trollhättan, may not have any significant improvements regarding time savings and thereby no economic benefits. However, the approach for generating an optimized measurement program in RD&T and IPS may have major improvements in other facilities within the aerospace industry which has also resulted in an instruction manual to be used for potential implementation.
480

Determination of the hydraulic characteristics of unsaturated soils using a centrifuge permeameter

McCartney, John Scott, 1979- 28 August 2008 (has links)
A new experimental approach to determine the hydraulic characteristics of unsaturated soils using a centrifuge permeameter was developed in this study. Specifically, the centrifuge permeameter is used to determine the water retention curve (WRC), which quantifies the energy required to retain water in the soil pores during wetting and drying, and the hydraulic conductivity function (K-function), which quantifies the soil's change in impedance to water flow as it becomes unsaturated. An aim of this study is the promotion of using experimentally-derived hydraulic characteristics in engineering practice. Accordingly, the goals behind development of the centrifuge permeameter were a reasonable testing time, measurement of all variables relevant to water flow in unsaturated soils, and a methodology allowing straightforward interpretation of experimental data to determine the hydraulic characteristics. Development of the centrifuge permeameter was guided by lessons learned from an evaluation of previous characterization approaches. Specifically, issues such as the use of steady-state or transient water flow, boundary condition effects, and the use of instrumentation were evaluated in conventional tests to better develop the centrifuge permeameter. Steady-state infiltration of water through a soil specimen instrumented with tensiometers to measure matric suction and time domain reflectometry to infer moisture content was found to be the most reliable means of characterization. Steady-state water flow permits straightforward, repeatable interpretation of instrumentation results, boundary conditions, and flow data to determine the hydraulic characteristics. Centrifugation is employed to decrease the time required to reach steady-state water flow through a soil specimen by imposing a centripetal acceleration on the infiltrating water. The water infiltration rate and centripetal acceleration can be independently controlled in the centrifuge permeameter in order to reach different target hydraulic conductivity values. Continuous, in-flight measurement of the variables relevant to hydraulic characterization is possible through an on-board data acquisition system. The experimental component of this study is focused on validation of the centrifuge permeameter and verification of the hydraulic characteristics obtained using this approach. Simultaneous determination of the WRC and K-function for a clay of low plasticity was found to be possible in less than a week using the centrifuge permeameter, whereas several months were required in conventional tests. Consistent measurements of hydraulic conductivity were obtained using this approach, and little hysteresis was observed in the hydraulic characteristics. Additional experiments were performed to evaluate the validity of different assumptions required to interpret the experimental data and different issues in centrifuge testing. Two major assumptions required in previous centrifuge permeameter approaches were evaluated using the instrumentation available in the centrifuge permeameter. During steady-state water flow in the centrifuge, the suction and moisture content were found to be relatively uniform along the longitudinal axis of the permeameter, and the outflow boundary was found to have a negligible influence on the suction profile. Settlement under the increased body forces in the centrifuge were found to be negligible for the soil investigated in this study. The hydraulic characteristics were found to be sensitive to the calibration of the transducers and sensors used to infer the water pressure and moisture content during centrifugation. Overall, the expeditious, direct determination of the hydraulic characteristics of unsaturated soils was successfully achieved using centrifuge technology. Accordingly, the centrifuge permeameter approach helps promote the use hydraulic characteristics of unsaturated soils in geotechnical engineering design.

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