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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.
41

Otimizacao do sistema de alvo interno do ciclotron CV-28 do IPEN-CNEN/SP

ARAUJO, SUMAIR G. de 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:38:54Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:00Z (GMT). No. of bitstreams: 1 02814.pdf: 7065257 bytes, checksum: 9cc7b6eb072600e69bbfbb2de41c251e (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
42

Reuse of steel and aluminium without melting

Cooper, Daniel January 2014 (has links)
Carbon dioxide emissions must be dramatically reduced to avoid the potentially dangerous effects of climate change. The steel and aluminium industries produce large amounts of carbon dioxide, accounting for 6% of anthropogenic emissions. Previous studies have shown that in these industries there is limited scope for further improvements in energy efficiency. Material efficiency strategies can, however, further reduce emissions. This thesis focuses on materially efficient reuse without melting. A scoping study of current reuse found three opportunities, an examination of which forms the basis of this thesis: reusing components at end of product life; extending the lifespan of products; and reusing manufacturing scrap. The opportunity to reuse components has received little attention to date and there is no clearly defined set of strategies or barriers to enable assessment of appropriate component reuse; neither is it possible to predict future levels of reuse. This thesis presents a global assessment of the potential for reusing steel and aluminium components. A combination of top-down and bottom-up analyses is used to allocate the final destinations of current global steel and aluminium production to final products. A substantial catalogue has been compiled for these products characterizing key features of steel and aluminium components including design specifications, requirements in use, and current reuse patterns. To estimate the fraction of end-of-life metal components that could be reused for each product, the catalogue formed the basis of a set of semi-structured interviews with industrial experts. The results suggest that approximately 30% of steel and aluminium used in current products could be reused. Barriers against reuse are examined, prompting recommendations for redesign that would facilitate future reuse. In order to understand how product lifespans can be extended it must first be understood why products are replaced. A simple framework with which to analyse failure is applied to the products that dominate steel use, finding that they are often replaced because a component/sub-assembly becomes degraded, inferior, unsuitable or worthless. In light of this, four products, which are representative of high steel content products in general, are analysed at the component level, determining profiles of cumulative steel mass over the lifespan of each product. The results show that the majority of the steel components are underexploited – still functioning when the product is discarded. In particular, the potential lifespan of the steel-rich structure is typically much greater than its actual lifespan. Evidence from twelve case studies, in which product or component life has been increased, is used to tailor life-extension strategies to each reason for product failure, providing practical guidelines for designers. There is currently no commercial method of reusing small manufacturing scrap; however, previous research has demonstrated that extruded profiles can be created from small clean aluminium scrap, the scrap fragments solid-state welding together when extruded. In order to evaluate potential applications for these profiles four case studies are conducted in collaboration with aluminium producers and product manufacturers. It was found that strong and formable profiles could be produced from scrap. However, contaminated scrap sources, unreliable bonding and poor surface quality limited their potential for commercial use. No model exists for solid-state weld strength that is applicable to scrap extrusion. This prevents optimisation of the existing extrusion process and the development of new, potentially better, processes. Subsequently, this thesis presents a new model of weld strength as a function of relevant deformation parameters. The model is evaluated using a new experiment in which the deformation conditions can be varied independently. The experiments establish the basic relationships between deformation parameters and weld strength. The model correctly predicts these trends with predicted weld strengths typically lying within the experimental error range. The technical assessment of reuse presented in this thesis demonstrates the scope of potential change. If implemented, the opportunities presented would greatly increase the reuse of steel and aluminium, reducing the emissions emitted from liquid metal production in conventional recycling.
43

Effects of target's acceleration on alpha-beta tracking filters

Hoffman, Leo Henry 12 January 2010 (has links)
<p>This paper examines the effect of a target's acceleration on the Fire Control System (FCS) α-β tracking filters used on the AEGIS cruisers. A single inbound target model was used to test the response of the tracking filter to an accelerating target. This target would begin to approach the AEGIS cruiser from a variety of distances ranging from 40,00 yards to 200,000 yards. The target model would begin its approach starting with an initial velocity of 200 yards/sec. and after a preselected time, the target would undergo an acceleration for a tin1e duration of 5 seconds. The target's acceleration ranges from 1 g to 6g's. For target's acceleration of 1g or greater, the difference between the actual and filtered velocity increases linearly with increasing acceleration and is fairly independent of range and the noise present in the measurement data. For target's acceleration less than 1g, the difference between the actual and filtered velocity is a strong function of acceleration, noise and range. / Master of Engineering
44

Identification of novel microRNAs as potential biomarkers for the early diagnosis of ovarian cancer using an in-silico approach

Zahra, Latib January 2019 (has links)
Philosophiae Doctor - PhD / Ovarian cancer (OC) is the most fatal gynaecologic malignancy that is generally diagnosed in the advanced stages, resulting in a low survival rate of about 40%. This emphasizes the need to identify a biomarker that can allow for accurate diagnosis at stage I. MicroRNAs (miRNAs) are appealing as biomarkers due to their stability, non-invasiveness, and differential expression in tumour tissue compared to healthy tissue. Since they are non-coding, their biological functions can be uncovered by examining their target genes and thus identifying their regulatory pathways and processes. This study aimed to identify miRNAs and genes as candidate biomarkers for early stage OC diagnosis, through two distinct in silico approaches. The first pipeline was based on sequence similarity between miRNAs with a proven mechanism in OC and miRNAs with no known role. This resulted in 9 candidate miRNAs, that have not been previously implicated in OC, that showed 90-99% similarity to a miRNA involved in OC. Following a series of in silico experimentations, it was uncovered that these miRNAs share 12 gene targets that are expressed in the ovary and also have proven implications in the disease. Since the miRNAs target genes contribute to OC onset and progression, it strengthens the notion that the miRNAs may be dysregulated as well. Using TCGA, the second pipeline involved analysing patient clinical data along with implementing statistical measures to isolate miRNAs and genes with high expression in OC. This resulted in 26 miRNAs and 25 genes being shortlisted as the potential candidates for OC management. It was also noted that targeting interactions occur between 15 miRNAs and 16 genes identified through this pipeline. In total, 35 miRNAs and 37 genes were identified from both pipelines.
45

What is the Cost of an Adequate Vermont High School Education?

Rucker, Frank D. 01 February 2010 (has links)
Access to an adequate education has been widely considered an undeniable right since Chief Justice Warren stated in his landmark decision that “Today, education is perhaps the most important function of state and local governments…it is doubtful that any child may reasonably be expected to succeed in life if he is denied the opportunity of an education” (Brown vs. Board of Education, 1954). State constitutions establish rights to public education. State legislatures define expected outcomes and funding mechanisms to operate schools. Over the past sixteen years, plaintiffs have overwhelmingly prevailed in court cases where they have claimed that children have been denied access to an adequate education. Close scrutiny of state education finance systems revealed that few states had seriously attempted to determine objectively the amount of resources actually required to meet children’s learning requirements (Rebell, 2006). The purpose of this study is to assist policy makers in efforts to link resources with expected and mandated outcomes. The central question addressed is “what is the cost of an adequate high school education?” Recommendations focus on: 1) how an adequate education should be defined; 2) understanding conditions that affect student outcomes; 3) using successful school smart practices to allocate resources; and 4) the cost of adequacy. Findings from this study identified three spending thresholds. Vermont high schools that spent below $10,006/ pupil in total “current expense,” below $685/pupil in student support services, or below $595/pupil in administrative services, were very unlikely to have provided an adequate education. The statewide cost of adequacy requires an additional 4.2% in spending per pupil if all schools spend at the threshold level (based on 4 year averages 2002-2005). Recommendations articulate the need for policy makers to accept responsibility for setting student-outcome standards within a framework that considers student needs and the resources they are willing to appropriate to achieve mandated results. State funding incentives for allocating resources to schools must be reconsidered to address the inequitable system presently in place. Further research which articulates smart practices related to governance systems, school leadership, experiential learning opportunities, and instructional methods is necessary.
46

Prehension of a flanked target in individuals with amblyopia.

Buckley, John, Pacey, Ian E., Scally, Andy J., Barrett, Brendan T., Panesar, Gurvinder K. 16 October 2015 (has links)
yes / Purpose: Reduced binocularity is a prominent feature of amblyopia and binocular cues are thought to be important for prehension. We examine prehension in individuals with amblyopia when the target-object was flanked, thus mimicking everyday prehension. Methods: amblyopes (n=20, 36.4±11.7 years; 6 anisometropic, 3 strabismic, 11 mixed) and visually-normal controls (n=20, 27.5±6.3 years) reached forward, grasped and lifted a cylindrical target-object that was flanked with objects on either (lateral) side of the target, or in front and behind it in depth. Only 6 amblyopes (30%) had measurable stereoacuity. Trials were completed in binocular and monocular viewing, using the better eye in amblyopic participants. Results: Compared to visual normals, amblyopes displayed a longer overall movement time (p=0.031), lower average reach velocity (p=0.021), smaller maximum aperture (p=0.007) and longer durations between object contact and lift (p=0.003). Differences between groups were more apparent when the flankers were in front and behind, compared to either side, as evidenced by significant group-by-flanker configuration interactions for reach duration (p<0.001), size and timing of maximum aperture (p≤0.009), end-of-reach to object-contact (p<0.001), and between object contact and lift (p=0.044), suggesting that deficits are greatest when binocular cues are richest. Both groups demonstrated a significant binocular advantage, in that in both groups performance was worse for monocular compared to binocular viewing, but interestingly, amblyopic deficits in binocular viewing largely persisted during monocular viewing with the better eye. Conclusions: These results suggest that amblyopes either display considerable residual binocularity or that they have adapted to make good use of their abnormal binocularity.
47

Defining goal terms in development and health

Ogbeiwi, Osahon 18 November 2016 (has links)
Yes / Most academic literature uses ‘goal’, ‘aim’, ‘objective’ and ‘target’ as synonymous terms, but development and healthcare sectors define them as distinct etymological entities with varied and confusing interpretations. This review sought to constructively harmonise and differentiate each definition using a thematic framework. An inductive synthesis of definitions of the goal terms collected from 22 literature sources selected through a systematic internet search. Thirty-three specific definitions were reduced through serial category-building to single general definitions, and a set of theoretical themes generated as characteristic framework of each goal. Seven conceptual themes evolved from the synthesis, including the object, scope, hierarchy, timeframe, measurability, significance and expression of each goal term. Two terms, ‘goal’ and ‘aim’ are thematically similar as broad objects of immeasurable terminal impact, with a long-term timeframe. They signify organisational success, expressed as general purpose statements. ‘Objective’ is differentiated as a specific object of measurable intermediate outcome, with short-term timeframe. It signifies intervention effectiveness, expressed as a SMART statement. ‘Target’ is simply a specific quantifiable level of an indicator. Goal, aim, objective and target are conceptually different. New frameworks for writing complete goal statements are proposed, including impact and timeframe; and outcome, indicator and timeframe frameworks for aim and objective respectively
48

Digital Twin Placement for Minimum Application Request Delay with Data Age Targets

Vaezi, Mehrad January 2022 (has links)
Digital Twins are softwarized mirrors of physical systems. They can represent their corresponding physical counterparts in real-world applications and reflect the behavior of the latter under different scenarios with decent accuracy. In this thesis, we consider the case where an application requests data from multiple digital twins, each representing a physical system. The digital twins are hosted on execution servers located between the application and the set of physical devices. Each digital twin has to be periodically updated by its physical system and uses a portion of the execution server’s computing resource to refresh itself. Due to the scarcity of computation resources of the execution servers, in this thesis, we have tackled the problem of optimal digital twin placement onto a limited set of execution servers. We are aiming at minimizing the latency of the digital twins’ responses to the application’s requests while keeping the age of information of served data below a certain threshold. We first formulate the problem as an integer quadratic program (IQP) and then transform it into a semidefinite program (SDP). We prove that the problem is NP-complete and propose polynomial-time approximation algorithms that solve the problem with different trade-offs between the accommodation of the application’s request latency and the achievement of data age targets. / Thesis / Master of Applied Science (MASc)
49

Analysis of the performance of a parametric and nonparametric classification system : an application to feature selection and extraction in radar target identification /

Djouadi, Abdelhamid January 1987 (has links)
No description available.
50

Tecnologia de fabricação de alvos de aluminetos de urânio para produção de Mo-99 / Fabrication technology of uranium aluminide targets for Mo-99 production

Conturbia, Giovanni de Lima Cabral Romeiro 22 December 2017 (has links)
Neste trabalho os parâmetros de fabricação de alvos de dispersão UAlx-Al foram definidos aplicando-se a tecnologia de montagem e laminação de um conjunto núcleo-moldura-revestimentos tradicionalmente adotada na fabricação de placas combustíveis usadas em reatores de pesquisa. O uso das técnicas de dilatometria e difração de raios-x com refinamento de Rietveld contribuíram para desenvolver um processamento termomecânico para controle das fases presentes no núcleo do alvo. Um método inovador que permitiu o aumento da produtividade desse tipo de alvo também foi desenvolvido com base na laminação de múltiplos núcleos. O processo de fabricação mostrou-se adequado para produção de alvos com a especificação para produção de Mo-99 no Reator Multipropósito Brasileiro (RMB). / At this work, the manufacturing parameters of uranium aluminide dispersion targets (UAlx-Al) were defined applying the picture-frame technique, traditionally adopted to manufacture fuel plates used in research reactors. The use of dilatometric and X-ray analysis supported the development of a thermomechanical processing to control the phases present in the target meat. It was also developed a method to quantify uranium aluminides phases. An innovative method that allowed to increase the productivity of this type of target was also developed based on multicore rolling. The manufacturing process proved to be suitable for the production of targets fulfilling the specification to produce Mo-99 in the Brazilian Multipurpose Reactor.

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