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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.
11

The Effect of Process Parameters on Columnar-To-Equiaxed-Transition (CET) During Electron Beam-Powder Bed Fusion of Ferritic Stainless Steel

Ihensekhien, Doom Eleanor January 2022 (has links)
Electron Beam Powder Bed Fusion manufacturing of components is an additive manufacturing process that is complex and has widespread advantages for aerospace and many industrial processes. It reduces costs and has a larger powder particle size requirement. This gives the benefit of a higher mass deposition rate and thus faster production time compared to Laser-Powder Bed Fusion process. Powder bed manufacturing processes often lead to columnar grain structure formation along the build direction, resulting in components that have anisotropic physical and mechanical properties. This is a major problem that limits the applications of this technique. In order to promote equiaxed grains, as well as refine the columnar morphology and eliminate anisotropic properties, the roles of process conditions and presence of inoculants or heterogeneous nucleating sites are considered. In this study, the addition of titanium nitride inoculants is used to promote columnar to equiaxed grain transition in ferritic stainless steel with the use of melting strategies and variable process parameters. It has been found that the thermal gradient (G) to solidification rate (R) ratio (G/R ratio) controls grain morphology and texture: a low G/R ratio has been shown to promote the formation of equiaxed grains. The process conditions for this transition were investigated. The samples were analyzed after printing single line tracks in the Freemelt One machine, and thereafter studied with the aid of optical microscopy to ascertain the combination of machine parameters that results in a successful transition from columnar grains to equiaxed. The study concluded that there was an increase in the fraction of equiaxed grains under these conditions; a low thermal gradient, high scanning velocity and low area energy. Ultimately, further investigation will be needed to establish the exact process parameters that will promote the transition from columnar to equiaxed grains in ferritic stainless steel. The findings from this study can be used by future researchers to create solidification maps for this steel grade and assist industry to tailor specific textures in ferritic stainless steel to achieved desired microstructures and mechanical properties. / Electron  Beam  Powder  Bed  Fusion  (E-PBF)  tillverkning  av  komponenter  är en  additiv tillverkningsprocess  som  är  komplex  och  har  omfattande fördelar  för  flyg  och  många industriella processer. Det minskar kostnaderna och har ett större krav på pulverpartikelstorlek. Detta ger fördelen av en högre massavsättningshastighet och därmed snabbare produktionstid jämfört med Laser-Powder Bed Fusion-processen. Tillverkningsprocesser för pulverbädd leder ofta  till  att en kolumnformig  kornstruktur  bildas  längs  byggriktningen, vilket resulterar  i komponenter  som  har  anisotropa  fysikaliska  och mekaniska egenskaper.  Detta  är  ett  stort problem som begränsar tillämpningarna av denna teknik. För att främja likaxliga korn, samt förfina den kolumnära morfologin och eliminera anisotropa egenskaper, övervägs rollerna för processbetingelser och närvaron av ympmedel eller heterogena kärnbildningsställen. I denna studie  används  tillsatsen  av  inokulanter  av  titannitrid  för  att  främja  kolumnär  till  likaxlig kornövergång  i  ferritiskt rostfritt  stål  med  användning  av  smältstrategier  och  variabla processparametrar.  Det  har  visat  sig  att  förhållandet  mellan  termisk gradient  (G)  och stelningshastighet   (R)   (G/R-förhållande)   styr   kornmorfologi   och   textur:   ett   lågt   G/R- förhållande har visat sig främja bildningen av likaxliga korn. Processförhållandena för denna övergång undersöktes. Proverna analyserades efter att ha skrivit ut spår med en rad i Freemelt One-maskinen  och  studerades  därefter  med  hjälp  av  optisk mikroskopi  för  att  fastställa kombinationen   av   maskinparametrar   som   resulterar   i   en   framgångsrik   övergång   från kolumnära  korn till  likaxliga.  Studien  drog  slutsatsen  att  det  fanns  en  ökning  av andelen likaxliga korn under dessa förhållanden; en låg termisk gradient, hög avsökningshastighet och låg areaenergi. I slutändan kommer ytterligare undersökningar att behövas för att fastställa de exakta processparametrarna som kommer att främja övergången från kolumnära till likaxliga korn i ferritiskt rostfritt stål. Resultaten från denna studie kan användas av framtida forskare för att skapa stelningskartor för denna stålkvalitet och hjälpa industrin att skräddarsy specifika texturer i ferritiskt rostfritt stål för att uppnå önskade mikrostrukturer och mekaniska egenskaper.
12

Mechanisms of Blister Formation on Concrete Bridge Decks with Waterprooving Asphalt Pavement Systems

Hailesilassie, Biruk Wobeshet January 2013 (has links)
Bridge decks are commonly subjected to harsh environmental conditions that often lead to serious corrosion problems triggered by blisters under the hot mix asphalt bridge deck surfacing and secretly evolving during weather exposure until damage is often detected too late. Blisters may form under both the waterproofing dense mastic asphalt layer or under the waterproofing membrane which is often applied as additional water protection under the mastic asphalt (MA). One of the main technical issues is the formation of blisters under the membrane and asphalt-covered concrete structures caused by a complex mechanism governed by bottom-up pressure and loss of adhesion. A linear viscoelastic finite-element model was developed to simulate time-dependent blister growth in a dense mastic asphalt layer under uniformly applied pressure with and without temperature and pressure fluctuation. A finite element model was developed using ABAQUS with linear viscoelastic properties and validated with a closed form solution from first-order shear-deformation theory for thick plates. In addition, the blister test was conducted on different samples of MA in the laboratory and digital image correlation measurement technique was used to capture the three-dimensional vertical deflection of the MA over time. It was found that the blister may grow continuously under repeated loading conditions over subsequent days. With respect to blistering under waterproofing membranes, mechanical elastic modeling and experimental investigations were performed for three different types of membranes under in-plane stress state. The orthotropic mechanical behavior of a polymer modified bitumen membrane (PBM) was determined from biaxial test data. Finally, blister tests by applying controlled pressure between orthotropic PBMs and concrete plates were performed for studying the elliptical adhesive blister propagation using digital 3D image correlation. The energy calculated from elliptical blister propagation was found comparable to the adhesive fracture energy from standard peeling tests for similar types of PBMs. This indicates that the peeling test assists to evaluate and rank the adhesive properties of different types of membranes with respect to blister formation at room temperature without conducting time consuming and complicated pressurized blister propagation tests using digital 3D image correlation. / <p>QC 20130625</p>
13

A gestão da assistência farmacêutica como uma proposta na saúde em rede

Inocêncio, Marcos Alexandre de Carvalho 27 April 2010 (has links)
Made available in DSpace on 2016-04-25T16:45:27Z (GMT). No. of bitstreams: 1 Marcos Alexandre de Carvalho Inocencio.pdf: 985560 bytes, checksum: 7c1d3aa53e36121cdcaf0b99b4771975 (MD5) Previous issue date: 2010-04-27 / The aim of this research was to evaluate the performance of the current model of the heath system, considering the participation of its agents, and taking into account the theory of net organization. Moreover, it was to identify the contribution of pharmaceutical assistance management, through PBMs, in the forming of the heath system as a net. The importance of this research was that it can contribute for understanding what could be better for the current heath systems models. Its features include the conceptual revision of the heath environment, concerning the bibliographical revision of the net society, as well as the information net. The analysis of the contribution of the pharmaceutical assistance for the net organization was developed though the theoretical understanding of PBMs practices and case studies. Its samples involved the study of Brazilian companies that offer pharmaceutical assistance as a way to benefit its contributors and its dependents. The collection of the initial data was possible through the analysis of the data bank of a PBM. The result showed that the health environment is in crisis, as well as it has persistent problems. Therefore, changes are required. The required changes demand an organized model with common interest, inter-relation, as well as interdependence among the heath system actors. As this system lacks such features, there is a blank in the health system, which is focused more on the isolated relationships than in the systemic perspectives. It was demonstrated that there is not such an environment when it comes to dynamic relationships and integrations. In other words, it is not organized in an effective net. The studies of the PBM practices and the analyzed cases present a new opportunity for this environment, which can contribute to the net organization in the health system. The efficient management of the pharmaceutical assistance, by means of a PBM, can generate relevant, qualified and common sense information. Moreover, such information can contribute effectively to the necessary health transformation, and it can also bring some knowledge to the system / Este trabalho teve como objetivo avaliar o desempenho do atual modelo do sistema de saúde, considerando a participação dos seus agentes, frente à teoria da organização em rede. E como objetivo específico, identificar, conceitualmente, a contribuição da gestão da assistência farmacêutica, por meio das empresas gestoras de assistência farmacêutica - PBMs, na composição do sistema de saúde em rede. Sua importância reside na contribuição para a compreensão do que pode favorecer os atuais modelos de sistemas de saúde. Caracteriza-se pela revisão conceitual do ambiente de saúde em face da revisão bibliográfica da sociedade em rede e da rede de informação. A análise da contribuição da assistência farmacêutica para a organização em rede foi desenvolvida por meio do entendimento teórico das práticas das PBMs e por estudos de casos, cuja amostra envolveu estudo de empresas brasileiras que oferecem assistência farmacêutica como benefícios aos seus colaboradores e seus dependentes. O levantamento dos dados foi feito pela análise do banco de dados de um PBM. Os resultados demonstram um ambiente de saúde em crise com problemas persistentes e que carecem de mudanças urgentes. As mudanças requeridas apontam para um modelo organizado em rede caracterizado pelo interesse comum, pela inter-relação e pela interdependência entre os atores dos sistemas de saúde, que pela falta destas características deixa uma lacuna no ambiente de saúde que apresenta um cenário focado mais nas relações isoladas do que nas perspectivas sistêmicas. Não há um ambiente em termos de relações e integrações dinâmicas, ou seja, organizado em uma rede eficiente. O estudo das práticas das PBMs e dos casos analisados nos mostra uma nova oportunidade neste ambiente que surge para a contribuição da organização em rede do sistema de saúde. A gestão eficiente da assistência farmacêutica, por meio de uma PBM, gera informações relevantes, qualificadas e de interesse comum, que pode contribuir significativamente para a transformação necessária da saúde, trazendo novos conhecimentos ao sistema
14

Policy-based routing for mobile ad hoc networks running HTR protocol

Souza, Gabriela Coutinho Machado de 13 September 2013 (has links)
The increasing growth of mobile devices in the whole world, and the forecasts for the coming years has been indicated by several reports. Nonetheless, this need for ubiquitous collaboration has brought new possibilities and challenges to the scientific community. Mobile Ad hoc Networks (MANETs) emerges in this scenario allowing devices to interconnect autonomously, without the need of a fixed infrastructure, in order to provide communication and information services. Due to such decentralization and the natural constraints of mobile devices, it remains, to this day, a challenge to provide efficient routing for MANETs. In this dissertation we propose new routing enhancements based on policies for MANETs running the HTR protocol. We consider the role(s) a user associated to a device performs within an organization. Hence our policies can guide the routing based on these roles. With this scheme we improve communication according to different business needs and scenario requirements. To this end, we propose a set of policies that affects the routing behavior and present four case studies to present each policy. Then we analyze two policies in terms of end-to-end delay, and nodes’ lifetime. Through simulation we evaluate these metrics while varying parameters such as the amount of nodes participating in the network, the mobility characteristics, and the number of traffic sources. Our results show that it is possible to achieve these goals without causing great impact on the average end-to-end delay and energy consumption, two important metrics in any MANET evaluation. We explore the results in several scenarios and detail our findings, which can provide a different perspective for future MANET applications. / Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-03-10T18:42:15Z No. of bitstreams: 2 Dissertação Gabriela Coutinho.pdf: 1701782 bytes, checksum: 113328c2efdd1ba97f7a237d03cab574 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-11T17:46:06Z (GMT). No. of bitstreams: 2 Dissertação Gabriela Coutinho.pdf: 1701782 bytes, checksum: 113328c2efdd1ba97f7a237d03cab574 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013-09-13 / O crescimento das vendas de aparelhos móveis em todo o mundo, bem como as previsões para os próximos anos são apontadas em diversos relatórios. No entanto, essa necessidade de colaboração ubíqua trouxe novas possibilidades e desafios para a comunidade científica. Redes móveis ad hoc (Mobile Ad hoc Networks - MANETs) surgem diante deste cenário e permite que dispositivos se comuniquem de forma autônoma, sem a necessidade de uma infraestrutura predefinida para fornecer comunicação e serviços. Porém, essa descentralização junto com as restrições naturais dos dispositivos móveis, proporcionar roteamento eficiente para MANETs permanece um desafio. Este trabalho propõe novas melhorias para o roteamento em MANETs que utilizam o protocolo HTR. Também considera o papel que usuários associados aos dispositivos desempenham dentro de uma organização. Desta forma, as políticas desenvolvidas podem guiar o roteamento também com base nestes papéis. Com este esquema, é possível melhorar a comunicação de acordo com necessidades de negócio e requerimentos de cenário. Para este fim, esta dissertação propõe um conjunto de políticas que afetam o comportamento do roteamento e analisa os impactos em termos de atraso, energia gasta e tempo de vida dos nós. Através de simulações, essas métricas são avaliadas também com variação de parâmetros como a quantidade de nós que participam da simulação, as características de mobilidade e o número de fontes de tráfego. Resultados mostram que é possível atingir esses objetivos sem causar grande impacto negativo no atraso fim a fim e no consumo de energia, duas métricas importantes em avaliações de redes MANET. Nós exploramos esses resultados em diversos cenários e detalhamos nossas descobertas, que podem servir como uma perspectiva diferente para futuras aplicações de redes MANET.
15

Health Care Services for Child Survival and Performance-Based Management in Three Kosovo Municipalities

Mugaju, James 01 January 2018 (has links)
After the Republic of Kosovo's declaration of independence in 2008, new municipal structures were created with the charge of monitoring the delivery of health care services; yet, no mechanism for monitoring performance was ever implemented. With the public value theory as the foundation, the purpose of this multiple case study of 3 Kosovo municipalities was to understand issues surrounding the capacity of local government health department to monitor their performance related to the delivery of services. Relevant data were collected through focus-group discussions with 10 nurses, 9 directors of family medicine centers, and 12 municipal program managers. Purposeful semistructured interviews were conducted with 3 elected officials, 3 leaders of health care services, 3 policy leaders of relevant central-level ministries, and 9 participants from the national coalition of civil society organizations. All data were transcribed and coded per thematic analysis procedures. Results indicated that integrating the threefold value system of business value, social value, and governance value into municipal work plans and policy considerations will likely create a more solution-oriented service delivery at the municipal level. Furthermore, service delivery in the 3 municipalities appears to have improved over the past 5 years because of the pressure from active citizens, increased community engagement, and the institutionalization of home visits. Positive social change implications stemming from this study include the recommendation to central and local policy makers to fully integrate performance-based reporting systems into local legislation and policies. Such efforts can result in sustainable, equitable, and inclusive development, leading to stability and prosperity in Kosovo.
16

To What Extent EU Regulations and Consumer Behavior Have Affected the Expansion of Alternative Proteins: A Comparison of the Plant-Based and Cell-Based Meat Markets

Andersson, Josefine, Hannah, Kassidy January 2023 (has links)
Plant-based meat (PBM) fulfills the criteria set by the European Union regulations for the product to be sold in the EU and is currently a highly consumed conventional meat substitute in the region. Whereas, cell-based meat (CBM), as of July 2023, does not fulfill the criteria set by the EU regulations for the product to be legally sold in the EU. This is due to CBM companies not submitting the required Novel Food application to EFSA to recieve market approval. Therefore, CBM is currently not legally sold in the EU and not consumed in the region. This thesis analyzes the impact of EU regulations and consumer behavior, and how these factors affect the growth of the PBM and CBM markets. The restriction of the thesis, the PBM and CBM markets, has been chosen due to them being the primary forms of alternative proteins that are a more sustainable choice to conventional meat. The intention of the thesis is to bring attention to the interplay between law and business, and the implications of their interconnectedness. The thesis is written with the aspiration to answer the question; to what extent have EU regulations and consumer behavior affected the expansion of the plant and cell-based meat markets? To this end, we began with determining if the legal criteria of the regulatory framework applicable to PBM and CBM constitute equal regulatory conditions for the markets to expand in the EU. The regulatory framework referred to in the thesis is restricted to the primary legislations applicable to alternative proteins, which are the Genetically Modified Organisms (GMO) Regulation (EU) No 1829/2003, Novel Food Regulation (EU) 2015/2283, EU Food Law Regulation (EC) No 178/2002, Food Information to Consumers Regulation (EU) No 1169/2011, and EU labeling requirements. We then conducted a collection of previous research on both the PBM and CBM markets restricted to sustainability, retail market, consumer behavior, financial investment, development, and production processes and costs. Thereafter, we compared the previous research and the aforementioned EU regulations to conclude the impacts of the regulations and the differences in the legal application between PBM and CBM. We also conclude how consumer behavior impacts the growth of a market in addition to the regulatory requirements, and showcase their combined effects on the market. The results suggested that compliance with EU regulations determines if the products are authorized to be legally sold in the EU while consumer behavior influences market acceptance and the extent of growth. The key regulatory difference affecting the ability of CBM to comply and experience similar growth to PBM is the Novel Food Regulation, due to it categorizing cell-based products as novel foods. As of May 2023, no companies in the EU have submitted a Novel Food application to EFSA for CBM.
17

A Model Comparing Drug Utilization and Pharmaceutical Expenditures in Community and Mail-Order Pharmacy in a Retiree Population

Visaria, Jay L. January 2008 (has links)
No description available.
18

Nanostructured Thin Films Prepared by Planetary Ball Milling: Fabrication, Characterization and Applications

Sapkota, Raju 05 May 2022 (has links)
Planetary ball milling (PBM) is a well-known technique for efficient size reduction and homogenization of materials that has been used for many decades in various engineering and industrial processes. More recently, it has emerged as a unique top-down nanofabrication approach for nanomaterials based on nanoscale grinding. However, its potential application in nanostructured thin film fabrication has not been fully explored, as only a limited number of studies have been carried out. In this work, the effects of different grinding parameters (speed, time and solvents) were used to create previously unstudied nanoscale grinding conditions for nanostructured thin film materials via PBM with distinct and novel properties: Nanoparticles of silicon, titanium disilicide (TiSi2) and zinc oxide (ZnO) ground in different solvents (deionized (DI) water/ ethylene glycol (EG)/isopropyl alcohol) resulted in colloidal suspensions (or nanoinks) that could be used to coat various substrates (wafers, glass, flexible substrates, etc.) via drop casting, doctor blading or dip coating. Thin film properties such as wettability, electrical conductivity and gas sensing behavior are studied. The fabricated thin film coating properties could be tuned depending on the combination of starting powder materials, grinding parameters and resulting nanoparticle size/geometry: The influence of surface chemistry, solvent type, particle geometry, surface roughness and defects was shown to alter the conductivity and surface wettability of the resultant films. Thus, thin films formed using PBM nanoinks allow varied and tunable properties for advanced multi-functional coatings and devices. To demonstrate the feasibility of PBM nanoinks for thin film device applications, ZnO nanoinks were used to create chemiresistive gas sensors that operate at room temperature. By varying grinding parameters (speed, time and solvent) thin film sensors with differing particle sizes and porosity were produced and tested with air/oxygen against hydrogen, argon and methane target gas species, in addition to relative humidity. Grinding speeds of up to 1000 rpm produced particle sizes and RMS thin film roughness below 100 nm, as measured by atomic force microscopy and scanning electron microscopy. Raman spectroscopy, photoluminescence and x-ray analysis confirmed the purity and structure of resulting films. The peak gas sensor response was found for grinding parameters of 400 rpm (average particle size 275 nm) and 30 minutes (average particle size 225 nm) in EG and DI water, respectively, which could be correlated to an increased film porosity and an enhanced electron concentration resulting from adsorption/desorption of oxygen ions on the surface of ZnO nanoparticles. Similarly, gas response and dynamic behavior were found to improve as the operating temperature was increased between 100 and 150 °C. These results demonstrate the use of low-cost PBM nanoinks to optimize the active materials for solution-processed thin film gas/humidity sensors that can operate at room temperature for use in environmental, medical, food packaging, laboratory, and industrial applications. Overall, the nanogrinding technique can produce large amounts of nanoparticle suspension with variable particle sizes for creating thin films with tunable properties. By adjusting grinding parameters, the nanoparticle shape/size and properties can be varied resulting in nanoparticle inks for inexpensive coatings on various substrates and for use in different applications. / Graduate

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