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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 891 to 898 of 898 (0.053 seconds)| 891 |
BBT Side Mold AssyHemphill, Bill 07 June 2022 (has links)
This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass data, and layer names (formatted for AXYZ's ToolPath CAM software).
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Extension, Evaluation, and Validation of Load Based Testing for Residential and Commercial HVAC EquipmentParveen Dhillon (14203079) 02 December 2022 (has links)
<p>With rising temperatures, urbanization, population growth, improving economic wellbeing, decarbonization and electrification efforts, the demand for space cooling and heating equipment is continuously increasing around the world. To counteract the effect of rising demand for air conditioners and heat pumps on total energy consumption, peak electricity demand, and emissions, it is crucial to promote the development and market penetration of energy-efficient systems. Establishing minimum energy performance standards (MEPS), energy labeling and utility programs are some of the effective and tested methods for achieving this goal. The technical basis for these energy efficiency standards is a testing and rating procedure for estimating equipment seasonal performance from laboratory tests. Although the current rating procedures provide standardized metrics to compare different equipment performances, they fail to appropriately characterize the field representative performance of systems by not considering the effects of: 1) test unit embedded controls, thermostat, and realistic interactions with the building load and dynamics; 2) different climate zones and building types; and 3) and other integrated accessories for improving energy efficiency such as economizer for rooftop units (RTUs). Therefore, current approaches for performance ratings neither incentives the development and implementation of improved system and control designs nor consumers with a metric that represents the advanced systems' actual energy savings. To address this, a load-based testing methodology that enables dynamic performance evaluation of equipment with its integrated controls, thermostat, and other accessories was recently proposed. The test methodology is based on the concept of emulating the response of a representative building conditioned by the test unit in a test lab using a virtual building model. </p>
<p>In this work, the proposed load-based testing methodology was further extended, evaluated, and validated for residential heat pumps to integrate it into next-generation energy efficiency testing and rating procedures and to serve as a tool for engineers to develop and validate improved control algorithms in a laboratory setting. Further, a load-based testing method for evaluating the dynamic performance of RTUs with integrated economizers was also developed and demonstrated.</p>
<p>A load-based testing approach previously developed for residential cooling equipment is extended for heat pump heating-mode and demonstrated for a variable-speed system. The heat pump's typical dynamic behaviors are captured along with controller imperfections that aren't reflected in current testing approaches. Further, a comprehensive comparison was performed between the proposed load-based testing approach to the current steady-state testing approach in the U.S., AHRI 210/240, based on performance evaluation of three residential variable-speed heat pumps to understand the differences and their significance for the next-generation rating procedure. For cooling mode, steady-state testing estimates higher seasonal performance, but for heating mode, the steady-state testing approach estimates higher seasonal performance for warmer climates and is comparable for colder climates. The load-based testing methodology was validated by comparing the laboratory performance of a heat pump to that of a residential building in a controlled environment. The virtual building modeling approach for building loads and thermal dynamics effectively captured these characteristics of the house. The heat pump's cycling rate response with run-time fraction, which represents the unit's overall dynamic response, matched well between lab load-based tests and house tests. The test unit's COP difference for cooling and heating tests was within 3% between the two facilities, except for 9% in 95°F and 6% in 104°F cooling dry-coil test intervals. To evaluate the applicability of the developed load-based testing methodology as next-generation rating standards, its repeatability and reproducibility were assessed based on multiple heat pump round-robin tests conducted in two labs. Overall, reasonable to good repeatability was observed in load-based test results in both labs, however, poor reproducibility was observed except for one heat pump heating mode results. A root cause analysis of the observed differences along with recommendations for a next-generation rating approach are presented. This work aided in the development of a CSA (Canadian Standards Association) standard EXP07:19 and its subsequent revision for equipment rating based on load-based testing.</p>
<p>The application of the load-based testing methodology as a tool for the development and evaluation of a residential heat pump controller design was demonstrated. Further, a load-based testing methodology was developed and demonstrated for the dynamic performance evaluation of RTUs with integrated economizers in a test laboratory setting. Recommendations for future work to further develop and improve the repeatability, reproducibility, and representativeness of the load-based testing and rating approach for residential and commercial air conditioners and heat pumps are summarized at the end of the dissertation. </p>
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Internet censorship in the European UnionVerveris, Vasilis 30 August 2023 (has links)
Diese Arbeit befasst sich mit Internetzensur innnerhalb der EU, und hier
insbesondere mit der technischen Umsetzung, das heißt mit den angewandten
Sperrmethoden und Filterinfrastrukturen, in verschiedenen EU-Ländern. Neben
einer Darstellung einiger Methoden und Infrastrukturen wird deren Nutzung zur
Informationskontrolle und die Sperrung des Zugangs zu Websites und anderen im
Internet verfügbaren Netzdiensten untersucht. Die Arbeit ist in drei Teile
gegliedert. Zunächst werden Fälle von Internetzensur in verschiedenen EU-Ländern
untersucht, insbesondere in Griechenland, Zypern und Spanien. Anschließend wird
eine neue Testmethodik zur Ermittlung der Zensur mittels einiger Anwendungen,
welche in mobilen Stores erhältlich sind, vorgestellt. Darüber hinaus werden
alle 27 EU-Länder anhand historischer Netzwerkmessungen, die von freiwilligen
Nutzern von OONI aus der ganzen Welt gesammelt wurden, öffentlich zugänglichen
Blocklisten der EU-Mitgliedstaaten und Berichten von
Netzwerkregulierungsbehörden im jeweiligen Land analysiert. / This is a thesis on Internet censorship in the European Union (EU),
specifically regarding the technical implementation of blocking methodologies
and filtering infrastructure in various EU countries. The analysis examines the
use of this infrastructure for information controls and the blocking of access
to websites and other network services available on the Internet. The thesis
follows a three-part structure. Firstly, it examines the cases of Internet
censorship in various EU countries, specifically Greece, Cyprus, and Spain.
Subsequently, this paper presents a new testing methodology for determining
censorship of mobile store applications. Additionally, it analyzes all 27 EU
countries using historical network measurements collected by Open Observatory
of Network Interference (OONI) volunteers from around the world, publicly
available blocklists used by EU member states, and reports issued by network
regulators in each country.
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Placement of Controls in Construction Equipment Using Operators´Sitting Postures : Process and RecommendationsJalkebo, Charlotte January 2014 (has links)
An ergonomically designed work environment may decrease work related musculoskeletal disorders, lead to less sick leaves and increase production time for operators and companies all around the world. Volvo Construction Equipment wants to deepen the knowledge and investigate more carefully how operators are actually sitting whilst operating the machines, how this affects placement of controls and furthermore optimize controls placements accordingly. The purpose is to enhance their product development process by suggesting guidelines for control placement with improved ergonomics based on operators’ sitting postures. The goal is to deliver a process which identifies and transfers sitting postures to RAMSIS and uses them for control placement recommendations in the cab and operator environments. Delimitations concerns: physical ergonomics, 80% usability of the resulted process on the machine types, and the level of detail for controls and their placements. Research, analysis, interviews, test driving of machines, video recordings of operators and the ergonomic software RAMSIS has served as base for analysis. The analysis led to (i) the conclusion that sitting postures affect optimal ergonomic placement of controls, though not ISO-standards, (ii) the conclusion that RAMSIS heavy truck postures does not seem to correspond to Volvo CE’s operators’ sitting postures and (iii) and to an advanced engineering project process suitable for all machine types and applicable in the product development process. The result can also be used for other machines than construction equipment. The resulted process consists of three independent sub-processes with step by step explanations and recommendations of; (i) what information that needs to be gathered, (ii) how to identify and transfer sitting postures into RAMSIS, (iii) how to use RAMSIS to create e design aid for recommended control placement. The thesis also contains additional enhancements to Volvo CE’s product development process with focus on ergonomics. A conclusion is that the use of motion capture could not be verified to work for Volvo Construction Equipment, though it was verified that if motion capture works, the process works. Another conclusion is that the suggested body landmarks not could be verified that they are all needed for this purpose except for those needed for control placement. Though they are based on previous sitting posture identification in vehicles and only those that also occur in RAMSIS are recommended, and therefore they can be used. This thesis also questions the most important parameters for interior vehicle design (hip- and eye locations) and suggests that shoulder locations are just as important. The thesis concluded five parameters for control categorization, and added seven categories in addition to those mentioned in the ISO-standards. Other contradictions and loopholes in the ISO-standards were identified, highlighted and discussed. Suggestions for improving the ergonomic analyses in RAMSIS can also be found in this report. More future research mentioned is more details on control placement as well as research regarding sitting postures are suggested. If the resulted process is delimited to concern upper body postures, other methods for posture identification may be used.
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Le Ventre des Belges: miracle économique et restauration des forces de travail :origines et développement de la politique alimentaire du second immédiat après-guerre, 1914-1948 / Belly of Belgium: economic miracle and restoration of labour force :origin and development of second immediate postwar food policy, 1914-1948Bernardo Y Garcia, Luis Angel 01 July 2015 (has links)
Au cours du second immédiat après-guerre, la Belgique continue être soumise à une « économie de disette » qui s’est épanouie sous la seconde occupation. Afin d’assurer le ravitaillement alimentaire de la population et le maintien d’une activité économique, la puissance publique est contrainte d’organiser l’économie nationale traditionnellement acquise à la liberté du marché. Le temps de la pénurie alimentaire mondiale, la politique alimentaire va diriger l’approvisionnement général du pays par la stabilisation des prix et salaires, les importations, la mobilisation du secteur alimentaire, la distribution de l’alimentation, le rationnement et enfin la répression du « marché noir ». En dépit de la cherté des approvisionnements extérieurs et la régulation de la pénurie au niveau mondial, les gouvernements belges qui se succèdent depuis la Libération s’attachent à l’amélioration du niveau de vie d’une population affaiblie par l’occupation. Cette restauration des forces de travail est un corollaire indispensable à la reprise de l’activité économique et à la reconstruction du pays mais aussi au maintien de l’ordre établi et à la restauration politique. Cet objectif alimentaire a été assigné en exil et dans Bruxelles occupée par les élites dirigeantes – qu’elles soient politiques, économiques ou syndicales – dans une rare unanimité au même titre que la défense d’un « franc fort ». Le Parti communiste, qui participe au pouvoir dès le premier Gouvernement d’Union nationale de la Libération, va aussi adhérer à ces deux objectifs et se voit attribuer le lourd et ingrat portefeuille du Ravitaillement pendant la plus grande partie de son existence qui s’étale de septembre 1944 à décembre 1948. <p><p>Le choix assumé par une Belgique solvable d’une « politique d’abondance » aux dépens d’une planification des investissements se démarque des choix opérés par la France, les Pays-Bas ou la Grande-Bretagne impécunieux mais obsédés par la modernisation de leurs appareils de production respectifs. L’objectif belge d’apporter à la population – à coup de subventions massives – l’indispensable puis l’utile mais aussi le superflu va se maintenir jusqu’à la libération progressive des transactions et des prix et participe à la restauration rapide de l’économie belge transformatrice et exportatrice. Dès la fin de la guerre en Europe, un apparent « miracle économique » se produit en Belgique avec la reprise rapide des exportations à destination des pays limitrophes. Le processus de restauration économique a été initié dès les premières semaines de la Libération grâce aux prestations massives aux armées alliées et le « remboursement » inespéré d’une partie conséquente de celles-ci après-guerre. Dès le début de l’année 1947, la production industrielle belge rattrape le niveau d’avant-guerre alors que les productions charbonnière et agricole restent à la traîne. La politique alimentaire du second immédiat après-guerre place le consommateur au centre de l’économie agricole et multiple les contraintes du côté de l’offre en matière de transactions et de prix. Encombrée par l’héritage de l’occupation – en dépit d’un droit d’inventaire – elle rencontrera une forte opposition de la part du secteur alimentaire et principalement le monde agricole et le petit commerce. Ceux-ci déploieront des stratégies défensives à la fois politiques et illégales. Ces dernières s’expriment essentiellement depuis l’occupation par le détournement d’une part conséquente des maigres disponibilités alimentaires au profit de l’ennemi et d’une minorité au fort pouvoir d’achat. Quant au monde ouvrier organisé qui constitue aux yeux de la puissance publique le principal acteur du côté de la demande alimentaire, il va contester dès la Libération la politique d’austérité et l’inéquité des sacrifices demandés au nom de la restauration du pays. En dépit d’une pacification convenue entre les élites patronales et syndicales en échange de réformes sociales et la participation loyale des communistes au pouvoir, la seconde sortie de guerre sera marquée par de nombreuses grèves « sauvages » débordant le cadre syndical réformiste et communiste.<p><p>À vrai dire, la politique alimentaire mise en œuvre au cours de la seconde libération et du second immédiat après-guerre – ainsi que les réponses apportées par l’offre et la demande – ne peuvent être étudiées et comprises qu’en convoquant les crises alimentaires précédentes depuis la première occupation que la Belgique fut la seule à connaître en Europe occidentale sur la plus grand partie de son territoire, à l’exception du petit voisin grand-ducal. Tant la puissance publique, les élites dirigeantes que le monde agricole ou encore le mouvement ouvrier sauront tirer les enseignements des expériences passées. Enfin, la production agricole de la Belgique structurellement dépendante des importations massives de céréales et autres aliments du bétail s’inscrit depuis la fin du XIXème siècle dans une économie alimentaire mondialisée. Les crises alimentaires des temps de (sortie de guerre) traversées par la petite économie transformatrice et exportatrice sont avant tout des crises des approvisionnements extérieurs marquées par leur diminution voire leur quasi disparition. Au cours du second immédiat après-guerre, la politique alimentaire de la Belgique – comme celle des autres grands pays importateurs français, britannique ou néerlandais – sera toujours aussi tributaire des approvisionnements extérieurs régulés depuis la guerre par les Grands Alliés anglo-saxons. Ceux-ci passeront le relais en 1946 aux organismes internationaux gravitant autour des Nations Unies jusqu’aux abondantes récoltes mondiales de l’An 1948. / Doctorat en Histoire, art et archéologie / info:eu-repo/semantics/nonPublished
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Contrôle optimal des équations d'évolution et ses applications / Optimal control of evolution equations and its applicationsNabolsi, Hawraa 17 July 2018 (has links)
Dans cette thèse, tout d’abord, nous faisons l’Analyse Mathématique du modèle exact du chauffage radiatif d’un corps semi-transparent $\Omega$ par une source radiative noire qui l’entoure. Il s’agit donc d’étudier le couplage d’un système d’Equations de Transfert Radiatif avec condition au bord de réflectivité indépendantes avec une équation de conduction de la chaleur non linéaire avec condition limite non linéaire de type Robin. Nous prouvons l’existence et l’unicité de la solution et nous démontrons des bornes uniformes sur la solution et les intensités radiatives dans chaque bande de longueurs d’ondes pour laquelle le corps est semi-transparent, en fonction de bornes sur les données, Deuxièmement, nous considérons le problème du contrôle optimal de la température absolue à l’intérieur du corps semi-transparent $\Omega$ en agissant sur la température absolue de la source radiative noire qui l’entoure. À cet égard, nous introduisons la fonctionnelle coût appropriée et l’ensemble des contrôles admissibles $T_{S}$, pour lesquels nous prouvons l’existence de contrôles optimaux. En introduisant l’espace des états et l’équation d’état, une condition nécessaire de premier ordre pour qu’un contrôle $T_{S}$ : t ! $T_{S}$ (t) soit optimal, est alors dérivée sous la forme d’une inéquation variationnelle en utilisant le théorème des fonctions implicites et le problème adjoint. Ensuite, nous considérons le problème de l’existence et de l’unicité d’une solution faible des équations de la thermoviscoélasticité dans une formulation mixte de type Hellinger- Reissner, la nouveauté par rapport au travail de M.E. Rognes et R. Winther (M3AS, 2010) étant ici l’apparition de la viscosité dans certains coefficients de l’équation constitutive, viscosité qui dépend dans ce contexte de la température absolue T(x, t) et donc en particulier du temps t. Enfin, nous considérons dans ce cadre le problème du contrôle optimal de la déformation du corps semi-transparent $\Omega$, en agissant sur la température absolue de la source radiative noire qui l’entoure. Nous prouvons l’existence d’un contrôle optimal et nous calculons la dérivée Fréchet de la fonctionnelle coût réduite. / This thesis begins with a rigorous mathematical analysis of the radiative heating of a semi-transparent body made of glass, by a black radiative source surrounding it. This requires the study of the coupling between quasi-steady radiative transfer boundary value problems with nonhomogeneous reflectivity boundary conditions (one for each wavelength band in the semi-transparent electromagnetic spectrum of the glass) and a nonlinear heat conduction evolution equation with a nonlinear Robin boundary condition which takes into account those wavelengths for which the glass behaves like an opaque body. We prove existence and uniqueness of the solution, and give also uniform bounds on the solution i.e. on the absolute temperature distribution inside the body and on the radiative intensities. Now, we consider the temperature $T_{S}$ of the black radiative source S surrounding the semi-transparent body $\Omega$ as the control variable. We adjust the absolute temperature distribution (x, t) 7! T(x, t) inside the semi-transparent body near a desired temperature distribution Td(·, ·) during the time interval of radiative heating ]0, tf [ by acting on $T_{S}$. In this respect, we introduce the appropriate cost functional and the set of admissible controls $T_{S}$, for which we prove the existence of optimal controls. Introducing the State Space and the State Equation, a first order necessary condition for a control $T_{S}$ : t 7! $T_{S}$ (t) to be optimal is then derived in the form of a Variational Inequality by using the Implicit Function Theorem and the adjoint problem. We come now to the goal problem which is the deformation of the semi-transparent body $\Omega$ by heating it with a black radiative source surrounding it. We introduce a weak mixed formulation of this thermoviscoelasticity problem and study the existence and uniqueness of its solution, the novelty here with respect to the work of M.E. Rognes et R. Winther (M3AS, 2010) being the apparition of the viscosity in some of the coefficients of the constitutive equation, viscosity which depends on the absolute temperature T(x, t) and thus in particular on the time t. Finally, we state in this setting the related optimal control problem of the deformation of the semi-transparent body $\Omega$, by acting on the absolute temperature of the black radiative source surrounding it. We prove the existence of an optimal control and we compute the Fréchet derivative of the associated reduced cost functional.
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BBT Acoustic Alternative Top Bracing CADD Data Set-NoRev-2022Jun28Hemphill, Bill 22 July 2022 (has links)
This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are (a) a one-piece base for the standard kit's (Martin-style) bracing, (b) 277 Ladder-style bracing, and (c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.
The CADD data set for each of the three (3) top bracing designs includes (a) a nominal 24" x 18" x 3mm (0.118") Baltic birch plywood laser layout of (1) the one-piece base with slots, (2) pre-radiused and pre-scalloped vertical braces with tabs to ensure proper orientation and alignment, and (3) various gages and jigs and (b) a nominal 15" x 20" marking template.
The 'provided as is" CADD data is formatted for use on a Universal Laser Systems (ULS) laser cutter digital (CNC) device. Each CADD drawing is also provided in two (2) formats: Autodesk AutoCAD 2007 .DWG and .DXF R12. Users should modify and adapt the CADD data as required to fit their equipment. This CADD data set is released and distributed under a Creative Commons license; users are also encouraged to make changes o the data and share (with attribution) their designs with the worldwide acoustic guitar building community.
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BBT Acoustic Alternative Top Bracing CADD Data Set-NoRev-2022Jun28Hemphill, Bill 22 July 2022 (has links)
This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are (a) a one-piece base for the standard kit's (Martin-style) bracing, (b) 277 Ladder-style bracing, and (c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.
The CADD data set for each of the three (3) top bracing designs includes (a) a nominal 24" x 18" x 3mm (0.118") Baltic birch plywood laser layout of (1) the one-piece base with slots, (2) pre-radiused and pre-scalloped vertical braces with tabs to ensure proper orientation and alignment, and (3) various gages and jigs and (b) a nominal 15" x 20" marking template.
The 'provided as is" CADD data is formatted for use on a Universal Laser Systems (ULS) laser cutter digital (CNC) device. Each CADD drawing is also provided in two (2) formats: Autodesk AutoCAD 2007 .DWG and .DXF R12. Users should modify and adapt the CADD data as required to fit their equipment. This CADD data set is released and distributed under a Creative Commons license; users are also encouraged to make changes o the data and share (with attribution) their designs with the worldwide acoustic guitar building community.
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