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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.
151

[en] LIFE EMERGED QUICKLY, ONCE CLEARED - EXTINCT: THE CRATION OF STRATEGIES OF ESCAPE IN THE WRITING OF MAURA LOPES CANÇADO / [pt] VIDA SURGIDA RÁPIDA, LOGO APAGADA - EXTINTA: A CRIAÇÃO DE ESTRATÉGIAS DE FUGA DO HOSPÍCIO NA ESCRITA DE MAURA LOPES CANÇADO

MARIANA PATRÍCIO FERNANDES 09 October 2008 (has links)
[pt] O objetivo da dissertação é, a partir da obra de Maura Lopes Cançado, entender de que forma a escrita pode engendrar modos de fuga em uma situação aparentemente sem saída - como por exemplo, a internação em um hospital psiquiátrico, onde a escritora passou boa parte de sua vida. Hospício-deus é como Maura denomina esta sensação de clausura, que não se resume ao fato de estar internada, mas à outras experiências subjetivas, mais sutis e, por isso mesmo, mais difíceis de escapar. No entanto, é necessário fugir, pois é o próprio desespero de fuga e o desejo de evasão, que compõem a força motriz da sua escrita. Fez-se necessário neste trabalho, portanto, mapear a geografia do hospício-deus, em suas diferentes imagens, para elaborar através do diálogo entre o diário, a obra ficcional, e a leitura crítica, a melhor maneira de escapar a ele. / [en] The purpose of this work is, trough de writings of Maura Lopes Cançado, understand how literature is able to create ways of escape in situations where there are not, at least apparently, any exits, such as the confinement in a psychiatric hospital, where the writer spent most of her life. Asylum- god is how Maura called this sensation of enclosure, related also to other subjective experiences, more subtle and therefore more difficult to escape. However, it is necessary to flee, as it is the very despair of escape and the desire of evasion, the driving force of her writing. It was necessary in this work, therefore, to map the geography of this asylum-god to develop through the dialogue between the diary, the fictional work, and the literary criticism, the best way to evade.
152

Numerical calculations of quark-antiquark bound state masses, using the Bethe-Salpeter equation

Holdsworth, David January 1968 (has links)
No description available.
153

Acoustics and manufacture of Caribbean steelpans

Maloney, Soren E. January 2011 (has links)
The Caribbean steelpan is a pitched percussion instrument that originated in Trinidad and Tobago during the Second World War. Despite several research initiatives to improve the making of this relatively new instrument, several areas remain unaddressed. This thesis presents new approaches to help improve the making of the instrument. These approaches are situated in the production, vibration and material aspect of the steelpan. A novel sheet forming technology termed Incremental Sheet Forming (ISF) is applied to the production of miniature steelpan dishes. The thickness distribution in the wall of the ISF dishes is compared to the wall thickness distribution in a traditionally formed steelpan dish and a wheeled dish. Unlike traditional forming and wheeling, ISF produces stretching in only a portion of the walls of the formed dishes. Multi-pass ISF is used to extend the stretched zone but this extension is minimal. A break even analysis is also applied to investigate the fiscal viability of ISF application to the production of miniature and full size steelpan dishes. The application of ISF to steelpan making is found to be commercially profitable but could be jeopardised by the tuning stage of the steelpan making process. A preliminary study on the effect of impact on tone stability is conducted on a pair of notes on a fullsize steelpan and detuning is found more likely to occur by repeated impact of the note at its centre. Mode confinement in test-pans is also investigated. ISF is used to produce miniature test-pans with test-notes that are geometrically identical to notes on full size pans. It is possible to confine modes by varying the curvature of the bowl surrounding the test-note. The number of localised modes in the test-note increases as the radius of curvature of the surrounding bowl increases. The natural frequency of the first confined mode in the test-notes is sensitive to material springback in ISF and the mechanism of confinement appears to be due to the change in geometry that occurs between the flat test-note region and the bowl wall. This control of mode confinement may find use in future efforts to completely or partially automate the steelpan making process. Material damping and mechanical properties in low-carbon steel used to produce steelpans are researched. Damping and mechanical properties are extracted from low-carbon steel that is subjected to identical stages to the steelpan production process. Material damping trends suggest that an annealing temperature between 300°C and 400°C would be appropriate for the heat treatment of steelpans. Air-cooled and water-quenched low-carbon specimens exhibit comparable damping trends. Hardness increases in cold formed low-carbon specimens is attributed to strain hardening and not strain ageing. Investigation of damping trends and mechanical properties in ultra low bake-hardenable and interstitial-free steels reveals that a wider range of low-carbon steels may be suitable for steelpan making.
154

Perfil metabólico de bovinos de corte da raça Purunã / Metabolic profile of Purunã beef cattle breed

Leandro Cavalcante Lipinski 30 July 2013 (has links)
O objetivo do presente trabalho foi analisar a influência dos fatores etários, do puerpério, da castração, bem como a influência do confinamento no lipidograma e nas funções hepática e renal. Foram mensurados os valores séricos de colesterol, triglicérides, ácidos graxos não esterificados (NEFA), β-hidroxibutirato (B-HBO), ureia, creatinina, proteína total, albumina, aspartato-aminotransferase (AST), gama glutamil transferase (GGT), creatina quinase (CK) e glicose. Para realização do experimento foram utilizados 370 bovinos da raça Purunã. Os animais foram dispostos em 4 diferentes experimentos. Os dados foram analisados por ANOVA, usando o procedimento GLM do SAS. Concluiu-se que os constituintes metabólicos foram consideravelmente influenciados pela idade, sexo, puerpério e sistema de criação. Devido à grande quantidade de amostras estrategicamente colhidas, obtidas de diferentes manejos, também foi possível sugerir valores de referência para os análitos, nestes experimentos mensurados, para bovinos da raça Purunã de diferentes idades, sexos, fases do periparto e do puerpério e em confinamento. / The objective of this study was to analyze the influence of age, after childbirth, castration, as well as the influence of confinement on lipid profile and in liver and kidney function. We measured the levels of serum cholesterol, triglycerides, non-esterified fatty acids (NEFA), β-hydroxybutyrate (B-HBO), urea, creatinine, total protein, albumin, aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), creatine kinase (CK) and glucose. For the experiment we used 370 cattle breed Purunã. The animals were assigned to four different experiments. Data were analyzed by ANOVA, using the GLM procedure of SAS. It was concluded that the constituents were considerably influenced by metabolic age, sex, and postpartum creation system. Due to the large amount of strategically collected samples, obtained from different management, it was also possible to suggest values for the analytes, measured in these experiments, Purunã to breed cattle of different ages, sexes, and stages of peripartum and postpartum and confinement.
155

Experimental study of toroidal plasmas with non-circular cross-section.

Martin, Francis F. January 1977 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Engineering, 1977 / Vita. / Includes bibliographical references. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Nuclear Engineering
156

Transport Barrier Formation on HBT-EP

Stewart, Ian January 2021 (has links)
The physics of the biasing induced L-H transition and the mechanism for E×B shear flow suppression of turbulence are investigated on HBT-EP. Detailed measurements of the transverse length scales, behavior, and propagation direction of the edge turbulence match what is expected for the ion temperature gradient (ITG) mode. In the scrape-off layer (SOL), radially propagating blob-filament turbulence is identified and characterized, with velocities, sizes, and distributions comparable to measurements on other devices. Through systematic studies of the effect of applied shear flow on the turbulence, it is found that the E×B suppression of turbulence matches what is expected by the spectral shift model [Staebler et al. 2013 Phys. Rev. Lett. 110 055003]. Namely, the application of shear flow tilts the turbulent eddies and shifts the mean radial wavenumber ⟨kr⟩ of the turbulence spectrum from near zero to finite values, leading to a reduction in the turbulence intensity. The investigation also shows that both the decorrelation model and quench rule are able to reproduce the measured reduction of the turbulence intensity with applied shear flow when appropriate parameters are chosen. However, the decorrelation model fails to explain the increase in the shear-wise correlation length measured with increasing applied shear, and the quench rule fails to capture the suppression of the turbulence to a finite intensity at high shear. It is found that the same shearing effect that tilts the eddy structures and shifts ⟨kr⟩, enhances the gradient in the Reynolds stress at the edge and suppresses the blob-filament turbulence in the SOL. Although the biasing levels leading up to the transition are shown to enhance the Reynolds stress in a radially varying manner, it is found that the high flow shear in the H-mode state completely quenches the Reynolds stress. A careful examination of the spatial structure and temporal dynamics of the forcing terms in both dithering and one-step transitions reveals that the biasing induced L-H transition is caused by a reduction in poloidal viscosity at high flow velocity, in agreement with neoclassical theory. Nevertheless, the Reynolds force is measured to be comparable to the force from the electrode current, allowing the turbulence driven stress to work synergistically (or antagonistically) with forces from the probe to achieve the critical poloidal flow velocities. The similarities between the transition criteria on HBT-EP and other devices indicate that reduction of poloidal viscosity leading to the transition to improved confinement regimes may be a universal trait among toroidal confinement devices. The application of resonant magnetic perturbations (RMPs) is shown to both reduce the Reynolds stress and increase the biasing threshold for the transition. The observed reduction in the Reynolds stress stems from a reduction in the intensity of the underlying turbulence; namely, a decrease in the amplitude of velocity fluctuations in regions where the Reynolds stress is high without an applied RMP. This study has therefore expanded the current understanding of transport barrier formation in magnetic confinement devices.
157

Looking Within: Examining the Short- and Longer-Term Consequences of Criminal Justice Confinement on Internalizing Problems

January 2020 (has links)
abstract: This study examined whether periods of secure confinement in juvenile detention, jails, and prisons are associated with short- and longer-term increases in adolescent males’ internalizing problems during adolescence and young adulthood. Data came from a longitudinal community sample of 506 male adolescents who were assessed every six months for three years and annually for ten subsequent years. At each assessment, participants reported on their confinement experiences and internalizing problems (i.e., anxiety, depression) during the recall period. Fixed-effects models examined within-individual changes in internalizing problems before, during, and after youth reported any overnight stay in a correctional facility, after controlling for the time-varying confounds of externalizing problem behaviors and previous justice system contact. Additionally, this study tested whether changes in the participants’ internalizing problems varied depending on the confinement facility (i.e., juvenile detention, jail, prison). Overall, results indicated that internalizing problems increased during periods where participants had been confined in a facility. In contrast, there were no changes in internalizing problems in the period prior to confinement and internalizing problems returned to baseline levels in the year following confinement. Facility-specific analyses indicated confinement in prison was associated with the largest increase in internalizing problems. Findings from this study indicate confinement does influence internalizing problems and interventions sensitive to internalizing problems should focus on providing services during confinement and immediate reentry period. / Dissertation/Thesis / Masters Thesis Criminology and Criminal Justice 2020
158

Fabrication and Characterization of Geometrically Confined Fe3Sn2 Skyrmion-based Devices

GONG, CHEN 27 June 2018 (has links)
Skyrmion is a topologically protected nanometer-sized spin configuration, which makes it a promising candidate for future memory devices. All skyrmion applications are based on the formation and manipulation of spin textures in nanostructured elements. Therefore, fabrication of geometrically confined skyrmion-based nanodevices is an essential step in the investigation of skyrmion properties. In this study, my research mainly focuses on the fabrication of high-quality Fe3Sn2 nanostripes with different geometric parameters for Lorentz transmission electron microscopy (LTEM) by a focused ion beam (FIB) system. The observation of the skyrmions using LTEM was mainly performed by Dr. Qiang Zhang, although I have deeply involved the discussion on new samples to be fabricated based on the results obtained from LTEM and also performed some LTEM experiments. To investigate the formation process and thermal stability of skyrmions in a geometrically confined environment, I have fabricated more than fifty high-quality nanostripes with a width of 265-4,000 nm. Studying with LTEM, a distinct evolutionary path of stripe-skyrmion transformation is observed after gradually increasing the magnetic field (out-of-plane direction) and the critical magnetic field of skyrmion is found to decrease with an increasing strength of confinements. Moreover, a series of racetrack devices with controlled thicknesses (125-404 nm) is fabricated to study the effect of thickness in skyrmion formation. Overall, in order to obtain less damaged, flat skyrmion-based devices by FIB system, experimental parameters are optimized and fabrication skills are improved. This method develops the possible application of centrosymmetric frustrated magnet Fe3Sn2 in skyrmion-based racetrack devices.
159

Shape-shifting and instabilities of plates and shells

Stein-Montalvo, Lucia 06 May 2021 (has links)
Slender structures like plates and shells -- for which at least one dimension is much smaller than the others -- are lightweight, flexible, and offer considerable strength with little material. As such, these structures are abundant in nature (e.g. flower petals, eggshells, and blood vessels) and design (e.g. bridge decks, fuel tanks, and soda cans). However, with slenderness comes suceptibility to large and often sudden deformations, which can be wildly nonlinear, as bending is energetically preferable to stretching. Though once considered categorically undesirable, these instabilities are often coveted nowadays in the engineering community. They provide mechanical explanations for observations in nature like the wrinkled structure of the brain or the snapping mechanism of the Venus fly trap, and when precisely controlled, enable the design of functional devices like artificial muscles or self-propelling microswimmers. As a prerequisite, these achievements require a thorough understanding of how thin structures "shape-shift" in response to stimuli and confinement. Advancing this fundamental knowledge is the goal of this thesis. In the first two chapters, we consider the shape-selection of shells and plates that are confined by their environment. The shells are made by residual swelling of silicone elastomers, a process that mimics differential growth, and causes initially flat structures to irreversibly morph into curved shapes. Flattening the central region forces further reconfiguration, and the confined shells display multi-lobed buckling patterns. These experiments, finite element (FE) simulations, and a scaling argument reveal that a single geometric confinement parameter predicts the general features of this shape-selection. Next, in experiments and molecular dynamics (MD) simulations, we constrain intrinsically flat sheets in the same manner, so that their center remains flat when we quasi-statically force them through a ring. In the absence of planar confinement, these sheets form a well-studied conical shape (the developable cone or d-cone). Our annular d-cone buckles circumferentially into patterns that are qualitatively similar to the confined shells, despite the distinct curvatures and loading methods. This is explained by the dominant role of confinement geometry in directing deformation, which we uncover via a scaling argument based on the elastic energy. There are also marked differences between the way plates and shells change shape, which we highlight when we investigate the rich dynamics of reconfiguration. In the final two chapters, we demonstrate how mechanics, geometry, and materials can inform the design of structures that use instabilities to function. We observe in experiments that dynamic loading causes a spherical elastomer shell to buckle at ostensibly subcritical pressures, following a substantial time delay. To explain this, we show that viscoelastic creep deformation lowers the critical load in the same predictable, quantifiable way that a growing defect would in an elastic shell. This work offers a pathway to introduce tunable, time-controlled actuation to existing mechanical actuators, e.g. pneumatic grippers. The final chapter aims at reducing the energy input required for bistable actuators, wherein snap-through instability is typically induced by a stimulus applied to the entire shell. To do so, we combine theory with 1D finite element simulations of spherical caps with a non-homogeneous distribution of stimuli--responsive material. We demonstrate that restricting the active area to the shell boundary allows for a large reduction in its size, while preserving snap-through behavior. These results are stimulus-agnostic, which we demonstrate with two sets of experiments, using residual swelling of bilayer silicone elastomers as well as a magneto-active elastomer. Our findings elucidate the underlying mechanics, offering an intuitive route to optimal design for efficient snap-through. / 2022-05-06T00:00:00Z
160

The Physical & Mental Effects of Solitary Confinement

Leonard, Dillon, Martin, Katelyn, Teague, Sean 14 April 2022 (has links)
Introduction and Background: Solitary confinement has been a controversial topic in recent years among jail and prison systems. Solitary Confinement is the act of isolating a person in a prison or jail for up to 23 hours a day. These long periods of isolation can cause serious mental and physical damages to a human. Purpose Statement: The purpose of this research is to understand the effects, both mental and physical, that solitary confinement has on a person. How does solitary confinement effect a person’s body and mind, and what interventions can be used to help prevent these changes? Literature Review: Key terms used in research involved “nursing” and “solitary confinement effects.” 15 studies were used in the research. Data bases searched involved Findings: Our findings tell us that both physical and mental damages are done to people in confinement, and the damages get worse the longer they are confined. Anger towards the legal systems and loss of empathy are some damages that occurred even for years after solitary time was finished. Conclusions: The take home message is that solitary confinement does more harm than good for almost anyone that spends time in confinement. There needs to be better interventions in helping these people such as promoting exercise and behavior cognitive therapy. There are better ways to handle people in prisons than to isolate them and cause massive damage to their health.

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