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1
Herimanitra, Lyla. "Anthropologie de la filière Raphia : de la Brousse Malgache à Paris : acheter et vendre aux risques de la tradition et du fihavanana." Paris 7, 2007. http://www.theses.fr/2007PA070020.
Full textAbstract:
Cette these se propose d'etudier le raphia, depuis son extraction jusqu'a sa transformation en produits commerciaux de standard mondial, de soulever les problemes humains qltil suscite et de mettre en lumiere les patrimoines socioculturels qu'il incarne, et ceci, a travers le vecu et le regard des hommes et des femmes qui vivent du travail qu'il engendre. Concretement, il s'agit de tenter, du point de vue anthropologique, de preciser les liens qui existent entre les techniques des differentes phases de la transformation du raphia d'une part et l'organisation familiale, sociale et religieuse d'autre part; et de devoiler les correlations etroites et fortes qui rapprochent les vivants, les ancetres et le raphia. Au-dela de la simple description de situations et des comportements observes, je cherche a rendre compte du sens que les gens «acteurs sociaux», donnent a leur vie et aux symboles a travers lesquels elle est vecue par rapport au raphia. L'ouvrage s'applique a restituer la dynamique de la filiere raphia et a mettre en relief les interactions des differents aspects des espaces sociaux touches par l'exploitation de la fibre vegetale et de son commerce. Cette demarche me conduit a emprunter la route du raphia, a en remonter la filiere, l'unique ouverture des regions concernees au monde exterieur et par la meme occasion, a apprehender le sens que le commerce du raphia revele de la conception traditionnelle malgache de l'economie. La production de la fibre de raphia, l'unique source de revenu des habitants ainsi que ses empreintes sur le quotidien, comme la vie ou la mort, sont visitees de l'interieur dans ses moindres recoins et subtilitesThis thesis ams at studying raffia, from its extraction to its transformation into commercial goods of world standard, at raismg the human issues it creates and at bringing out the socio cultural heritages it embodies, through the real-life experience and the look of the men and women who earn their living thanks to the work raffia generates. Concretely speaking, this thesis is about trying, from an anthropologic point of view, to specify the links existing between the techniques used in the different stages for the transformation of raffia on the one hand and family, social and religious organisation on the other hand ; and to unveil the narrow and strong correlations linking the livings, their ancestors and raffia. Further than the mere description of observed situations and comportments, i consider bringing to light the direction peuple « social players » give to their lives and the symbols through which the» lives are lived concerning raffia. This work wants to reproduce the dynamics of the raffia network and to highlight the interactions of the different aspects of the social spaces touched by the exploitation of this plant fibre and its commerce. This process drives me to take the raffia path and to go back along this network. The only door to the rest of the world for these regions, and at the same time, to understand the meaning the commerce of raffia reveals concerning the madagascan traditional conception of economy. The production of raffia fibre, the inhabitants' unique source of income as well as its prints on daily life, such as life and death, are studied from the inside in their deepest recesses and subtleties
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Kouob, Bégné Serge. "Les forêts matures de terre ferme du sud-est Cameroun." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210222.
Full textAbstract:
La structuration spatiale de la diversité floristique constitue un outil de base pour la gestion durable des forêts tropicales. La complexité des forêts tropicales s’accommode mal des généralisations et des extrapolations qui aboutissent le plus souvent à des résultats imprévisibles. La présente étude a pour but (1) d’identifier les groupements végétaux des forêts matures de terre ferme de la RBD et partitionner la variance floristique ;(2) de comparer les forêts matures de terre ferme de la RBD à d’autres forêts tropicales sur la base de la diversité, de la structure et de la dominance des taxons; (3) d’évaluer la structuration spatiale de la diversité dans les forêts à Gilbertiodendron dewevrei de la RBD; (4) d’évaluer l’influence des densités de Raphia regalis sur la diversité des forêts matures de terre ferme de la RBD; (5) de déterminer le statut phytogéographique des forêts à Coula edulis du sud-est Cameroun ;(6) de Comparer les différents types forestiers de forêts matures de terre ferme du sud-est Cameroun sur la base de la diversité et de la structure. La Réserve de Biosphère du Dja (RBD) ainsi que le massif forestier Ngoyla Mintom font partie sont faiblement perturbés par les activités anthropiques et font partie de l’initiative de conservation transfrontalière TRIDOM. La variance floristique dans la RBD est principalement expliquée par les distances géographiques, l’indice de continentalité et la topographie. La part de variance floristique non expliquée est élevée et due aux facteurs stochastiques et à l’hétérogénéité environnementale non détectée. La diversité locale dans les forêts matures de terre ferme de la RBD est élevée, bien que n’atteignant pas les degrés extrêmes observés dans certaines forêts tropicales d’Asie et d’Amérique du Sud. La diversité de différenciation est faible et positivement corrélée aux distances géographiques. Quelques taxons sont dominants tandis que le nombre d’espèces rares est élevé. Dans les forêts à Gilbertiodendron dewevrei, les strates arborescentes sont moins diversifiées que celles des forêts hétérogènes aussi bien à l’échelle locale qu’à celle du site. A surface égales, les strates herbacées des forêts monodominantes sont aussi diversifiées que celles des forêts hétérogènes. La diversité de différenciation est négativement corrélée à l’amplitude de la monodominance et aux distances géographiques même en absence des effectifs de Gilbertiodendron dewevrei. Raphia regalis influence négativement les densités dans les strates arborescentes, contribuant ainsi à une diversité locale artificiellement élevée. Les forêts à Coula edulis du sud-est Cameroun correspondent à la continuité de la partie continentale du bas-guinéen. Le district congolais du Dja suit les contours de la rivière dont il porte le nom. Les types forestiers matures de terre ferme du sud-est Cameroun diffèrent aussi bien du point de vu de leur structure que de leurs diversités à différentes échelles. Toute intervention doit tenir compte des spécificités de chacune d’entre elles. Les taux élevés d’espèces rares et la faible diversité des forêts à Gilbertiodendron dewevrei, l’isolement relatif des forêts à Coula edulis du district congolais du Dja, les faibles densités d’espèces arborescentes dans les forêts à Raphia regalis et le statut conservatoire de l’espèce dominante, la diversité élevée des forêts mixtes à l’échelle du sud-est Cameroun et du bassin du Congo.Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
3
Byatt, Nancy. "Rapid Access to Perinatal Psychiatric Care in Depression (RAPPID): A Master’s Thesis." eScholarship@UMMS, 2004. http://escholarship.umassmed.edu/gsbs_diss/731.
Full textAbstract:
Depression is the leading cause of disability among women of reproductive age worldwide. Upwards of 1 in 5 women suffer from perinatal depression. This condition has deleterious effects on several birth outcomes, infant attachment, and children’s behavior/development. Maternal suicide causes 20% of postpartum deaths in depressed women. Although the vast majority of perinatal women are amenable to being screened for depression, screening alone does not improve treatment rates or patient outcomes. Obstetrics/Gynecology (Ob/Gyn) clinics need supports in place to adequately address depression in their patient populations. The primary goal of this thesis is to develop, refine, and pilot test a new low-cost and sustainable stepped care program for Ob/Gyn clinics that will improve perinatal women’s depression treatment rates and outcomes. We developed and beta tested the Rapid Access to Perinatal Psychiatric Care in Depression (RAPPID) Program, to create a comprehensive intervention that is proactive, multifaceted, and practical. RAPPID aims to improve perinatal depression treatment and treatment response rates through: (1) access to immediate resource provision/referrals and psychiatric telephone consultation for Ob/Gyn providers; (2) clinic-specific implementation of depression care, including training support and toolkits; and (3) proactive depression screening, assessment, and treatment in OB/Gyn clinics. RAPPID builds on a low-cost and widely disseminated population-based model for delivering psychiatric care in primary care settings. Formative data and feedback from key stakeholders also informed the development of RAPPID. Our formative and pilot work in real-world settings suggests RAPPID is feasible and has the potential to improve depression detection and treatment in Ob/Gyn settings. The next step will be to compare two active interventions, RAPPID vs. enhanced usual care (access to resource provision/referrals and psychiatric telephone consultation) in a cluster-randomized trial in which we will randomize 12 Ob/Gyn clinics to either RAPPID or enhanced usual care.
4
Byatt, Nancy. "Rapid Access to Perinatal Psychiatric Care in Depression (RAPPID): A Master’s Thesis." eScholarship@UMMS, 2015. https://escholarship.umassmed.edu/gsbs_diss/731.
Full textAbstract:
Depression is the leading cause of disability among women of reproductive age worldwide. Upwards of 1 in 5 women suffer from perinatal depression. This condition has deleterious effects on several birth outcomes, infant attachment, and children’s behavior/development. Maternal suicide causes 20% of postpartum deaths in depressed women. Although the vast majority of perinatal women are amenable to being screened for depression, screening alone does not improve treatment rates or patient outcomes. Obstetrics/Gynecology (Ob/Gyn) clinics need supports in place to adequately address depression in their patient populations. The primary goal of this thesis is to develop, refine, and pilot test a new low-cost and sustainable stepped care program for Ob/Gyn clinics that will improve perinatal women’s depression treatment rates and outcomes. We developed and beta tested the Rapid Access to Perinatal Psychiatric Care in Depression (RAPPID) Program, to create a comprehensive intervention that is proactive, multifaceted, and practical. RAPPID aims to improve perinatal depression treatment and treatment response rates through: (1) access to immediate resource provision/referrals and psychiatric telephone consultation for Ob/Gyn providers; (2) clinic-specific implementation of depression care, including training support and toolkits; and (3) proactive depression screening, assessment, and treatment in OB/Gyn clinics. RAPPID builds on a low-cost and widely disseminated population-based model for delivering psychiatric care in primary care settings. Formative data and feedback from key stakeholders also informed the development of RAPPID. Our formative and pilot work in real-world settings suggests RAPPID is feasible and has the potential to improve depression detection and treatment in Ob/Gyn settings. The next step will be to compare two active interventions, RAPPID vs. enhanced usual care (access to resource provision/referrals and psychiatric telephone consultation) in a cluster-randomized trial in which we will randomize 12 Ob/Gyn clinics to either RAPPID or enhanced usual care.
5
Herrera, Díaz Areli. "Regeneration and plastid transformation approaches in Arabidopsis thaliana and Rapid-Cycling Brassica rapa." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-134542.
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Chandler, Emily A. "A Molecular Study of the Mitochondrial Genome and Invasions of the Veined Rapa Whelk, Rapana venosa." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539617856.
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O'Keefe, David John. "Differential Expression of Isopentenyl Transferase and Cytokinin Oxidase/Dehydrogenase During Pod and Seed Development in Brassica." Thesis, University of Canterbury. Biological Sciences, 2012. http://hdl.handle.net/10092/7040.
Full textAbstract:
Consistency of yield and quality of seed are traits not yet optimised by the brassica seed industry in
New Zealand. As of 2008, seed producers in Canterbury, New Zealand, exported approximately $18m
of brassica seed. However, there is a need to increase both seed quantity and/or quality. The plant
hormone group, the cytokinins, regulates many stages of plant growth and development, including
cell division and enhancement of sink strength, both of which are important processes in seed
development and embryonic growth.
The two gene families targeted in this project play a key role in maintaining cytokinin homeostasis.
Isopentenyl transferase (IPT) catalyzes the rate limiting step in the formation of cytokinins, and
cytokinin oxidase/dehydrogenase (CKX) irreversibly inactivates cytokinins. The aim of this project
was to identify those cytokinin gene family members expressing specifically during the early phases
of pod and seed development. Initially this study used a rapid-cycling Brassica rapa (RCBr) because
of its rapid life cycle, then, as the project developed, a commercial crop of forage brassica (B.
napus) was studied.
Reverse transcriptase PCR (RT-PCR) and BLAST analysis was used to identify putative IPT and
CKX genes from RCBr and B. napus. Quantitative reverse transcriptase polymerase chain reaction
(qRT-PCR) was used to measure the expression of individual gene family members during leaf,
flower, pod and seed development. BrIPT1, -3, and -5, and BrCKX1, -2, -3, and -5/7 and were shown
to express differentially both temporally and spatially within RCBr root, stem, leaf, seed, and pod
tissues. BnIPT1, 3 and 7 and BnCKX1, 2, 5 and 7 were also differentially expressed. Particularly
strong expression was shown by BrIPT3, BrIPT5 and BrCKX2 in developing seeds. Both Brand
BnIPT3 expressed strongly in maturing leaves.
In normal plant growth and development, biosynthesis and metabolism of cytokinin is tightly
regulated by the plant. Increasing the levels of cytokinins during seed development, either by over
expressing IPT3 or IPT5, or decreasing the expression of CKX2, or both, could potentially increase
both seed yield and seed vigour.
8
Green, Rebecca A. "Morphological Variation of Three Populations of the Veined Rapa Whelk, Rapana venosa, an Invasive Predatory Gastropod Species." W&M ScholarWorks, 2001. https://scholarworks.wm.edu/etd/1539617974.
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Ware, Catherine C. "Temporal and Spatial Variation in Reproductive Output of the Veined Rapa Whelk (Rapana venosa) in the Chesapeake Bay." W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539617793.
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Westcott, Erica S. "A Descriptive Study of the Reproductive Biology of the Veined Rapa Whelk (Rapana venosa) in the Chesapeake Bay." W&M ScholarWorks, 2001. https://scholarworks.wm.edu/etd/1539617776.
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Jestel, Ethan Alexander. "Imposex as an Indication of Butyltin Exposure in the Veined Rapa Whelk (Rapana venosa), a Chesapeake Bay Invader." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539617967.
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Dias, Antonio Carlos Pires. "Solidificação de ligas euteticas livres de Pb para soldagem : parametros termicos e microestrutura." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264429.
Full textAbstract:
Orientadores: Amauri Garcia, Noe CheungDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: As ligas de solda à base de estanho apresentam excelente fluidez e temperaturas de trabalho ideais para a união de componentes eletrônicos. A solda com ligas do sistema estanho chumbo é a mais comum para soldas em eletrônica. Entretanto, há muitas preocupações com o uso do chumbo, devido aos diversos efeitos adversos na saúde humana e contaminação do meio ambiente. Por essas razões, na maioria dos países o chumbo já é condenado e proibido de ser incorporado em diversos produtos. Neste sentido, a indústria eletrônica está de olho em soldas livres de chumbo que possam substituir a clássica solda estanho-chumbo. É objetivo deste trabalho analisar a solidificação de ligas eutéticas dos sistemas Sn-Ag e Sn-Cu, que são duas ligas com potencial de substituição. Foram desenvolvidos experimentos para determinar a influência do acabamento superficial da chapa molde nos parâmetros térmicos de solidificação durante a solidificação direcional ascendente em regime transitório de extração de calor de ligas eutéticas Sn-Pb, Sn-Cu e Sn-Ag. Foram utilizados dois tipos de acabamentos superficiais na chapa molde: lixado e ranhurado, para investigar as condições de afinidade metal/substrato. Foi desenvolvida uma abordagem teórico-experimental para determinar quantitativamente as variáveis térmicas, tais como: coeficiente de transferência de calor global (hg) e velocidade de deslocamento da frente de solidificação. As micro estruturas de solidificação foram caracterizadas e os espaçamentos dendríticos secundários (?2) foram medidos na direção longitudinal dos lingotes, e correlacionados com as variáveis térmicas que atuaram durante a solidificação.
Abstract: Tin based alloys for welding applications have excellent fluidity and adequate temperature working range to join electronic components. The most used tin alloys for welding is the eutectic Sn-Pb alloy. However, there are some concerns about lead, due to hazardous effects to health and to environment. Due to theses reasons, many countries condemn and prohibit the use of lead in several products. In this sense, the electronic industries are looking for lead-free solder alloys with a view to replace the traditional Sn-Pb eutectic alloy. The aim of this work is to analyze the solidification of Sn-Ag and Sn-Cu eutectic alloys which are potential alloys candidates to replace the eutectic Sn-Pb alloy. Experiments were conducted to determine the influence of the mold wall roughness on the thermal solidification parameters during the upward unsteady-state directional solidification of eutectic Sn-Pb, Sn-Cu and Sn-Ag alloys. Two different kinds of surface mold finishing, sanded and grooved, were used in order to analyze metal/substrate affinity. A combined theoretical and experimental approach has been used to quantitatively determine such thermal variables, i.e., transient global heat transfer coefficient (hg) and solidification growth rates. The microstructures have been characterized and the secondary (?2) dendrite arm spacings were measured along the castings length and correlated to transient solidification thermal variables.
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
13
Moyer, Ilan Ellison. "Rapid prototyping of rapid prototyping machines." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45321.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaf 50).
Rapid prototyping tools empower individuals to create almost anything. Unfortunately, these tools are still far too expensive for personal ownership. The do-it-yourself community has responded with a slew of home-made rapid prototyping machines, but development times are slow because of the complexity of the necessary control system and the need to design the mechanical elements from scratch. This thesis seeks to address both of these issues. A control system is developed which treats the machine as a distributed Internet Zero network controlled by a software virtual machine with the benefits of simplified configuration and greater flexibility. A low cost circuit board milling machine, built as the test bed for this distributed controller, is described in detail. Finally, a parametrically designed XY table is introduced as a prototype for a universal machine axis and a first step towards the creation of reusable machine designs. These contributions will hopefully aid in accelerating the development of new rapid prototyping machines.
by Ilan Ellison Moyer.
S.B.
14
Sambu, Shiva Prasad. "A design for manufacturing method for rapid prototyping and rapid tooling." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17940.
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Herrera, Díaz Areli [Verfasser], and Hans-Ulrich [Akademischer Betreuer] Koop. "Regeneration and plastid transformation approaches in Arabidopsis thaliana and Rapid-Cycling Brassica rapa / Areli Herrera Díaz. Betreuer: Hans-Ulrich Koop." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2011. http://d-nb.info/1015500803/34.
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Cencig, Elsa Graciela Schusterman de. "Pirolise rapida de carvões minerais." [s.n.], 1990. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249495.
Full textAbstract:
Orientador: Ulf F. SchuchardtTese (doutorado) - Universidade Estadual de Campinas. Instituto de Quimica
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Doutorado
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Cante, Manuel Venceslau. "Solidificação transitoria, microestrutura e propriedades de ligas Al-Ni." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265081.
Full textAbstract:
Orientador: Amauri GarciaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: O desenvolvimento de microestruturas otimizadas durante o processo de solidificação são de fundamental importância nas propriedades e desempenho de produtos acabados baseados em ligas metálicas. Neste estudo é analisada a cinética envolvida no processo de solidificação, seus efeitos nos parâmetros macro e microestruturais e a sua conseqüente influência nas propriedades mecânicas. Com esse intuito, ligas hipoeutéticas do sistema binário são estudadas Al-Ni por meio de experimentos de solidificação vertical ascendente sob regime transitório de condução de calor. Os espaçamentos dendríticos primários (?1) e secundários(?2) foram medidos ao longo de todos os lingotes para cada uma das ligas analisadas e correlacionados com as variáveis térmicas de solidificação. Uma abordagem teórico-experimental é utilizada na determinação quantitativa de tais variáveis térmicas: coeficiente de transferência de calor na interface metal/molde, velocidade de deslocamento da isoterma liquidus, gradientes térmicos, taxa de resfriamento e tempo local de solidificação. Os dados experimentais referentes à solidificação das ligas são confrontados com os principais modelos teóricos de crescimento dendrítico da literatura. Este estudo aborda, também, a influência do teor de soluto nos espaçamentos dendríticos para as ligas estudadas. Do ponto de vista macroestrutural, verifica-se que a transição colunar/equiaxial (TCE) ocorre para ligas hipoeutéticas Al-Ni para uma taxa crítica de resfriamento de 0,16 K/s. Por ensaios de tração as propriedades mecânicas das ligas do sistema Al-Ni são correlacionadas com parâmetros da micro-estrutura dendrítica resultante do processo de solidificação. Verifica-se que os limites de escoamento e de resistência à tração crescem com o aumento da concentração de soluto e decrescem com o aumento dos espaçamentos dendríticos, ?1 e ?2. O alongamento específico, por outro lado, mostra-se independente da composição e do arranjo dendrítico. Para a liga Al-5%Ni foi também realizado um estudo de solidificação rápida por refusão da superfície a laser para análise das variações microestruturais e de dureza entre as áreas não tratadas e tratadas superficialmente.
Abstract: The development of optimized microstructures during the solidification stage of processing is of fundamental importance to the mechanical properties and to the performance of finished products of metallic alloys. In this study the kinetics of solidification and its effects on macro and microstructural parameters, as well as the consequent influence on the final mechanical properties are analyzed. Hypoeutectic Al-Ni alloys are studied by upward unidirectional solidification experiments under transient heat flow conditions. Primary (?1) and secondary (?2) dendrite arm spacings are measured along the castings for all alloys analyzed and correlated with transient solidification thermal variables. A combined theoretical/ experimental approach is used to quantitatively determine such thermal variables, i.e., transient metal/mold heat transfer coefficients, tip growth rates, thermal gradients, tip cooling rates and local solidification time. The experimental data concerning the Al-Ni alloys solidification are compared to the main predictive dendritic models from the literature and the dependence of dendrite arm spacing on the alloy solute content is also analyzed. From the macrostructural point of view, it is found that the CET occurs for a critical value of cooling rate of about 0.16 K/s for hypoeutectic Al-Ni alloys.With a view to correlate mechanical properties to dendrite arm spacings, tensile testings were carried out. It is found that the ultimate tensile strength and the yield strength increase with increasing alloy solute content and with decreasing primary and secondary dendrite arm spacings. In contrast, the elongation is found to be independent of both alloy composition and dendritic arrangement. For the Al 5%Ni alloy a rapid solidification study is carried out by using laser surface remelting in order to permit microstructural and microhardness variations throughout the resulting treated and untreated zones, to be analysed.
Doutorado
Materiais e Processos de Fabricação
Doutor em Engenharia Mecânica
18
Bertelli, Felipe. "Simulação numérica e análise experimental do tratamento superficial por refusão a laser de uma liga Al-Fe." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264533.
Full textAbstract:
Orientadores: Amauri Garcia, Noé CheungDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho, o software ANSYS, baseado no Método dos Elementos Finitos, é adaptado para a simulação tridimensional do fluxo de calor no processo de refusão superficial a laser. A análise numérica é validada com resultados simulados por outros modelos existentes na literatura para casos de refusão superficial a laser de alumínio puro e com resultados simulados e experimentais de uma liga Al-5%Ni. Ensaios experimentais próprios foram realizados em amostras de uma liga Al-1,5%Fe, utilizando um laser à fibra dopado com Itérbio, com potência máxima disponível de 2 kW. Para efeito comparativo, as trilhas foram feitas variando-se valores de velocidade de deslocamento do feixe laser para um mesmo valor de potência. Observou-se que a microestrutura tanto do substrato quanto da zona tratada apresentou morfologia tipicamente celular. As microestruturas resultantes dos tratamentos a laser foram analisadas através de microscopia eletrônica de varredura, sendo observados espaçamentos celulares extremamente refinados na área tratada a laser refletindo no aumento significativo da dureza confirmado por ensaios de microdureza Vickers. Uma técnica de dissolução parcial das amostras tratadas a laser foi aplicada para evidenciar os intermetálicos no substrato e na região tratada a laser, mostrando a modificação da redistribuição dos intermetálicos no interior da poça fundida e dando indicações de aumento da resistência à corrosão na região tratada
Abstract: In this work, the software ANSYS, based on the Finite Element Method, is adapted to simulate the three-dimensional heat flux during the laser remelting surface treatment. The numerical analysis is validated against theoretical results furnished by other models from the literature for laser surface remelting of aluminum and against theoretical and experimental results of Al-5wt%Ni alloy samples. Laser remelting experiments with Al-1,5%wtFe samples have been carried out by using a 2kW Yb fiber laser. For comparative effects, the laser tracks were performed with different laser beam velocities for a fixed value of power. It was observed that both the substrate and the treated region had a typical cellular morphology. The microstructures resulting from the laser treatment were analyzed by using electron scanning microscopy and very refined cell spacing has been observed, which can induce a significant hardness increase confirmed by Vickers microhardness tests. A partial dissolution technique has been performed to foreground the intermetallics at the substrate and at the laser treated zone, showing the intermetallics redistribution inside the molten pool and giving indications of increased corrosion resistance on the treated region
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Amer, Dena Ahmed Mohamed. "Estrogen Receptor-Beta Dependent Activities of Dietary Compounds in a Genetically Modified Rat Raphe Nuclei-Derived Cell Line." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-70312.
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Estrogens greatly affect the activity and connectivity of serotonergic neural cell populations, which extend from clusters of nuclei in the brainstem, termed the raphe nuclei, where estrogen receptor β is the most abundantly expressed estrogen receptor subtype. Estrogenic effects on the raphe nuclei are primarily important for influencing various neuropsychological behaviors, including depression, mood swings and anxiety behaviors. Because of this connection, phases of intense hormone fluctuations for instance during menopause are often associated with several mood disturbances that often reduce the quality of life of menopausal women. Accordingly, long-term use of hormone replacement therapy appeared to be the method of choice for many menopausal women to help alleviate vasomotor symptoms, which may include neuropsychological changes such as depression. However, given the limitations and number of serious health risks attributed to hormone replacement therapy, natural compounds such as phytoestrogens are receiving widespread awareness due to their occurrence in medicinal plant extracts and a wide variety of food items including dietary supplements with respective health claims. Flavonoids, particularly the isoflavones and the naringenin-type flavanones, belong to a group of polyphenolic plant-derived secondary metabolites known to possess estrogen-like bioactivities. Nevertheless, little is known about their transactivational activity and their potential to regulate endogenous gene expression of estrogen responsive genes in the raphe nuclei due to the lack of suitable cellular models expressing sufficient amounts of functional estrogen receptor β.
Hence, a raphe nuclei-derived cell line that expresses a functional estrogen receptor β was sought as a model to investigate effects of flavonoids in vitro. In this regard, RN46A-B14 cells derived from embryonic day 13 rat medullary raphe nuclei were primarily used in this study as the main cellular model. Nonetheless, expression of endogenous estrogen receptor β in these cells was not sufficient to pursue downstream investigations of estrogen-dependent activities. To overcome this deficit, a rat raphe nuclei-derived in vitro model that overexpresses a functional estrogen receptor β was initially established (herein termed RNDA cells) by stably transducing its parent cell line, RN46A-B14 cells, with a suitable lentiviral expression vector encoding a human estrogen receptor β gene. The stable expression and the functional characterization of the transgenic receptor was confirmed by Western blot analysis and luciferase reporter gene assays, respectively. The same reporter gene assay was used to scrutinize the transactivational activity of the flavonoids in RNDA cells. Key results revealed that Genistein, Daidzein, Equol, Naringenin and 8-Prenylnaringenin demonstrated high transactivational activity in a concentration-dependent manner by stimulating luciferase expression from an estrogen responsive element-regulated reporter gene construct transiently transfected in RNDA cells. Low transactivational activity was observed in RNDA cells in response to increasing concentrations of 7-(O-prenyl)naringenin-4'-acetate. However, no transactivational activity was noticed in response to 6-(1,1-Dimethylallyl)naringenin in the studied cell model. All effects elicited by the flavonoids were antagonized by the pure estrogen receptor antagonist, Fulvestrant, indicating that all substances act by binding to and activating the transgenic ERβ. Additional effects were observed in RNDA cells in response to a co-treatment of 1 µM of either Genistein or Daidzein, but not Equol, with 10 nM 17β-Estradiol. Slight antagonistic effects were observed in the same studied cell line when either 8-Prenylnaringenin or 7-(O-prenyl)naringenin-4'-acetate, but not Naringenin or 6-(1,1-Dimethylallyl)naringenin, were co-added with 17β-Estradiol.
Results from the reporter gene assays were validated on the basis of regulation of mRNA expression of estrogen responsive genes following the global assessment of 17β-Estradiol-induced gene expression in this cell line using a DNA microarray technique. Out of 212 estrogen-regulated genes with at least two-fold change of expression, six were selected according to specific features of estrogenic regulation of expression. The expression of the six selected 17β-Estradiol-regulated genes was validated using quantitative real-time PCR analysis. The regulation of mRNA expression of the selected genes in response to the tested flavonoids was then investigated in RNDA cells. Additionally, because RNDA cells encode a temperature-sensitive mutant of the Simian Virus 40 large T-antigen, their neuronal differentiation is constitutive upon shifting them from conditions promoting proliferation (permissive temperature) to differentiation (non permissive temperature). Hence, the regulation of mRNA expression of the selected genes in response to the tested flavonoids was additionally investigated as RNDA cells differentiate.
In RNDA cells grown under proliferative conditions, 17β-Estradiol up-regulated mRNA expression of camello-like 5, sex determining region Y-box 18 and keratin type I cytoskeletal 19. Similar effects were observed in response to 8-Prenylnaringenin, Genistein, Daidzein and Equol. In addition, 17β-Estradiol down-regulated mRNA expression of neurofilament medium polypeptide and zinc finger DHHC-type containing 2. Similar effects were observed in response to 8-Prenylnaringenin, Naringenin, Genistein, Daidzein and Equol. Yet, no effect was observed on the regulation of mRNA expression of solute carrier family 6 member 4 in response to 17β-Estradiol or the flavonoids in RNDA cells grown under proliferative conditions. When RNDA cells were shifted to conditions promoting differentiation, changes in cell morphology, in mRNA expression levels and in responsiveness towards 17β-Estradiol or the flavonoids were observed. These expression studies additionally highlighted some of the genes as indicator genes for RNDA cellular differentiation.
The newly established RNDA cell line should prove useful to elucidate basic physiological properties of estrogen receptor β in the raphe nuclei. The present study should serve as the basis to help shed light on molecular and cellular mechanisms following the action of phytoestrogens, endocrine disruptors or other exogenous estrogen receptor ligands in neural cell populations, particularly the raphe nuclei, for further applications within the brain.
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Pfeifer, Rolf. "Entwicklung von Rapid-Prototyping-Verfahren zur Herstellung verlorener Modelle für den Feinguss." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28930.
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Truscott, M., van Vuuren M. Janse, G. Booysen, and Beer D. De. "Customised patient implants : future lifeline of the medical industry." Interim : Interdisciplinary Journal, Vol 7, Issue 1: Central University of Technology Free State Bloemfontein, 2008. http://hdl.handle.net/11462/384.
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Published ArticleLong-term growth in the additive fabrication industry will come from designs that are difficult, time-consuming, costly, or impossible to produce using standard techniques. Growth will occur with advances in the current additive processes, coupled with breakthroughs in new materials, which are expected to emerge over the next five to 10 years. These advanced materials will better satisfy the design requirements of many new products. The paper considers currently available technologies and discusses recent advancements in direct metal freeform fabrication and its potential of revolutionising the medical industry.
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Dimitrov, D., Beer N. De, and T. Centner. "Product and process innovations by means of rapid technologies." Journal for New Generation Sciences, Vol 4, Issue 1: Central University of Technology, Free State, Bloemfontein, 2006. http://hdl.handle.net/11462/487.
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Published ArticleOver the past few years, methods of layered manufacturing (LM) have advanced substantially to the point where they now provide vital strategic benefits to various organisations. One area of application where LM technologies have begun to reach a critical mass is in the development and production of high-performance tooling in different forming processes. With these tooling capabilities now available, the next challenge becomes the development of optimal process chains to minimise lead times and production costs, while still ensuring high quality of castings. The relevant issues that influence where a break-even point will be between different process chains and thereby also the point of selection between such optimal process chains according to different situations include among others:
- the size of production runs,
- part size and complexity, and
- the cast materials involved.
This paper reflects some of the experiences gained from an investigation towards developing a set of generic rules (guidelines) for the design of optimal process chains for sand casting prototypes of automotive components using LM methods, and more specifically the 3D Printing process.
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Pantano, Daniel. "The rapid unexpected." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001237.
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Koch, Thorsten. "Rapid mathematical programming." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973541415.
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Koski, Antti E. "Rapid frequency estimation." Worcester, Mass. : Worcester Polytechnic Institute, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-032806-165036/.
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Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: DSS; ECM; SVD; Singular Value Decomposition; rapid frequency estimation; frequency estimation. Includes bibliographical references (leaves 174-177).
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Garcia, Timmy J. "Rapid network design." Thesis, Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/37630.
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Approved for public release; distribution is unlimitedNetwork planning is a key element in the Marine Corps_ communications planning process. The ability to design and provide reliable network architecture directly affects the commander_s ability to control operations in an operational environment. Command-and-control systems technologies continue to change and evolve, adding complexity to network design. Portions of the current process of designing packet-switched networks are extremely prone to human design faults, which can adversely affect the reliability of the network. This thesis proposes an application prototype for network design that automates the creation of network configuration files. It describes the benefits achievable for development of such an application. Lastly, we demonstrate a working prototype that successfully produced configurations files that can easily be uploaded to network devices and create a functioning packet-switch network.
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Lafis, S. "Rapid microbial detection." Thesis, Cranfield University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357505.
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Bottalico, Davide. "Prototipazione rapida: dalla stereolitografia al bioprinting." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Questa trattazione, divisa concettualmente in tre parti, ha lo scopo di introdurre e spiegare il principio base delle principali tecnologie di Prototipazione Rapida esistenti, le sue maggiori applicazioni in ambito aerospaziale, ingegneristico e medico, approfondendo infine la moderna tecnica del bioprinting.
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Mommensohn, Maria de Fatima. "Ayvu rapyta : o fundamento da palavra." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/285086.
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Orientador: Regina Aparecida Polo MullerDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Artes
Made available in DSpace on 2018-08-03T21:20:06Z (GMT). No. of bitstreams: 1 Mommensohn_MariadeFatima_M.pdf: 3180336 bytes, checksum: 9b8b48b153bf12ca98ae3c7218475ba6 (MD5) Previous issue date: 2004
Resumo: Nesta dissertação, as palavras que norteiam o processo são brasilidade, inter/multiculturalidade, poética e corpo. A proposta é refletir sobre a composição coreográfica realizada no âmbito do contato entre culturas a partir da leitura da oração poema "Ayvu Rapyta", colhida por Leon Cadogan e Pierre Clastres entre os Mbya-Guarani. o mesmo grupo étnico que ainda hoje vive na periferia de São Paulo. O trabalho de campo com as aldeias guarani é especialmente ilustrativode como o corpo é o sujeito da cognição, a primeira e última instância em que o processo se realiza e que apenas se realiza porque é corpo. O texto que acompanha a obra artística compreende uma sucessão cumulativa entre a historicidade do tema, a abordagem processual da pesquisa e a experiência corporificada do acontecimento da dança
Abstract: In this paper the process key words are brazilianity, inter/ultraculturality, poetry and body. The author proposal is to reflect about the choreographic composition regarding the cultures contact that comes from the reading of the prayer-poem Ayiu Rapyta, collected by Leon Cadogan and Pierre Clastres from the Mbya Guarani, the same ethnical group that still inhabits the surroundings of São Paulo. The work in the guarani fields illustrated in a special way how body is the subject and the goal of cognition, the first and the last instance where the process takes places and it does just because it is body. The final text, that follows the performance, is a cumulative succession among the theme historicity, the process research approach and the embodied experience of dancing
Mestrado
Mestre em Artes
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Henshaw, Graham Robert. "Single-Session Design: Design Methodology in Compressed Timeframes Derived from the Robot Rivals Television Series." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32211.
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The purpose of this study is to document the design process as it is adapted to compressed timeframes. I have termed this adapted design process single-session design. This study will also explore the application of this type of design methodology in industry where the research and development phases of products are continually being compressed.
The primary research for this study is extracted from the examples of rapid design observed repeatedly on the Robot Rivals television series on the Do It Yourself network. The scope of this television series is a competition between two teams of engineering students to design, build, and operate a robot in a single day. The show yields an ideal platform to study the design process in a highly adaptive and compressed form. This study will show how the design process can be adapted to function in a fast-paced situation.
The design process in general has been studied for quite some time. However, to date there is no focused research on a specific design methodology that is intended for extremely short-term projects. This research provides insight into the situation where significant time constraints stimulate creativity and ingenuity in designs.Master of Science
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Aggenbacht, F. C. "Vacuum casting as a rapid manufacturing and prototyping option." Interim : Interdisciplinary Journal, Vol 4, Issue 1: Central University of Technology, Free State, Bloemfontein, 2005. http://hdl.handle.net/11462/421.
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Published ArticleThis article looks at the role that vacuum casting plays in the rapid prototyping and rapid manufacturing process. The accuracy to which components can be reproduced, by looking at the controllable factors in the casting process and the different types of materials that are available, were investigated and the process was also compared to other rapid prototyping and manufacturing processes in terms of cost effectiveness. Castings were made from a typical component under different operating conditions and the characteristics of the cast component, dimensions strength and surface hardness, were measured and plotted to determine the characteristics and accuracy of the process.
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Mattmann, Rudolf E. Mattmann Rudolf Mattmann Rudolf Mattmann Rudolf. "Rapid-Prototyping eingebetteter Systeme /." Zürich : vdf, Hochschulverlag AG an der ETH Zürich, 1997. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=3728125091.
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Mattmann, Rudolf Mattmann Rudolf Mattmann Rudolf. "Rapid-Prototyping eingebetteter Systeme /." Zürich, 1996. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11916.
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Roongrasamee, Soisangwan Wanpen Chaicumpa. "Rapid diagnosis of shigellosis /." Abstract, 1999. http://mulinet3.li.mahidol.ac.th/thesis/2542/42E-RoongrasameeS.pdf.
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Hochmuth, Carsten Alexander. "Rapid machine tool design." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9373.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (p. 206-208).
Rapid Machine Tool Design encompasses new materials and manufacturing and design processes that increase the speed and flexibility of the machine tool development process. Rapid design implies increased concurrency and overlap of design process steps, and it allows a quick and efficient response to market opportunities for new types of components or machinery. Rapid manufacturing implies use of new materials with reduced lead times for tooling and "one-off" components, simplified and deterministic processes and cost effective methods for customization and modular system design. This thesis describes design and manufacturing methods for polymer concrete structures in precision machine tools. The focus is on the modularity and unique capabilities of this process for rapid development of manufacturing equipment. Detailed material properties and process descriptions are presented. Traditionally, only the polymer concrete casting process is described, and the thesis expands on the discussion by reviewing the design process and other phases of the full machine tool life cycle. An understanding of the critical factors in the material composition and processing helps the designer understand possible variations in the polymer concrete mechanical properties and quality. This thesis contributes to the body of work on polymer concrete by providing a detailed guide for designing structural components, with analytical tools were applicable and examples from an actual machine design project. This thesis presents a comprehensive set of new design guidelines on how to build polymer concrete parts and tooling, merging the needs of the machine designer and the tooling builder. The thesis also presents a case study of a complete machine tool design with a polymer concrete structure. Methods and guidelines described in this thesis are successfully applied in the development and manufacture of the machine tool. The case study and the design chapters demonstrate that use of polymer concrete can be an enabling element for rapid machine tool design.
by Carsten Alexander Christoph Hochmuth.
Ph.D.
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Suwansantisuk, Watcharapan 1978. "Multipath aided rapid acquisition." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16697.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (p. 123-125).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Spread-spectrum systems with large transmission bandwidth present significant challenges from the standpoint of achieving synchronization before communication commences. This research investigates a rapid acquisition procedure that exploits the multipath to aid the synchronization. In particular, we consider a class of serial search strategies and determine the optimal search procedure for the uncertainty space consisting of N[sub]s total cells and N[sub]Q correct cells. We derive closed-form expressions for both the minimum and maximum mean acquisition times (MATs) and the conditions for achieving these limits. We prove that the fixed-step serial search (FSSS), with the step size N[sub]Q, achieves the near-optimal MAT. We also prove that the conventional serial search, in which consecutive cells are tested sequentially, and the FSSS with the step size N[sub]s - 1 should be avoided as they result in the maximum MAT. Analytical tools used in the research include Markov chain diagrams, the transformation of feasible spaces, and convexity theory. Our results apply to all signal-to-noise ratio values, regardless of the detection-layer decision rule and the fading distribution. The impact of this research is significant for the design, implementation, and deployment of spread-spectrum systems.
by Watcharapan Suwansantisuk.
S.M.
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Leonard, Sean Joseph. "System for rapid subtitling." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/36791.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (leaves 70-72).
A system for rapid subtitling of audiovisual sequences was developed, and evaluated. This new system resulted in average time-savings of 50% over the previous work in the field. To subtitle a 27-minute English lecture, users saved 2.2 hours, spending an average of 1.9 hours timing the monologue. Subtitling a 20-minute Japanese animation resulted in similar savings. While subtitling is widely practiced, traditional speech boundary detection algorithms have proven insufficient for adoption when subtitling audiovisual sequences. Human-edited timing of subtitles is a dull and laborious exercise, yet with some human-guidance, basic systems may accurately align transcripts and translations in the presence of divergent speakers, multiple languages, and background noise. Since no known, fully-automatic recognition systems operate with sufficient accuracy for production-grade subtitle times, during playback the system disclosed treats user-supplied times as a priori data and adjusts those times using extracted features from concurrent data streams. In the application's oracle subsystem, packaged algorithms called oracles preprocess, filter, and present media data, using that data to adjust user-supplied times.
(cont.) The on-the-fly timing subsystem gathers user-supplied times and coordinates the oracles' adjustment of the data. The application was developed with attention to user interface design and data format support, and was sent to users for structured feedback. From these data, system performance is discussed in terms of subtitle time accuracy, time spent by users, and avoidance of common pitfalls in subtitle generation.
by Sean Joseph Leonard.
M.Eng.
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Lewis-Åkerman, Erik. "Rapid Serial Visual Presentation." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20800.
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Rapid Seriell Visuell Presentation (RSVP) är ett koncept som har möjligheten att påverka hur en användare konsumerar sin dagliga läsning. Denna metod att läsa skiljer sig från traditionell läsning på så sätt att enbart ett (ibland flera) ord visas i varje bildsekvens i motsats till traditionell läsning då läsaren har full överblick över den statiska texten. Eftersom denna metod att läsa skiljer sig i sådan utsträckning från traditionell läsning så finns det ett behov av att utveckla RSVP till att bli en allt mer intuitiv upplevelse för läsaren. Sex testpersoner intervjuas, varvid resultaten analyseras och utvecklas till en prototyp.Rapid Serial Visual Presentation (RSVP) is a concept that changes every day reading into an efficient way of gathering information. Due to this innovative new way of reading, the importance of interaction that allows the user to interact with RSVP in an intuitive manner is needed to help the reader reach its full reading potential. This thesis puts existing RSVP programs to the test with the help of six participants in different ages. Through in-depth interviews with the participants, this thesis presents a possible new way of displaying information and interacting with RSVP. From analysing the results of the in-depth interviews, a prototype is created.
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Gerber, Guillaume. "Designing for rapid manufacture." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2008. http://hdl.handle.net/11462/42.
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Thesis (M. Tech.) -- Central University of Technology, Free State, 2008As the tendency to use sol id freeform fabrication (SFF) technology for the manufacture of end use parts grew, so too did the need for a set of general guidelines that would aid designers with designs aimed specifically for rapid manufacture. Unfortunately, the revolutionary additive nature of SFF technology left certain fundamental principles of conventional design for manufacture and assembly outdated. This implied that whole chapters of theoretical work that had previously been done in this field had to be revised before it could be applied to rapid manufacturing. Furthermore, this additive nature of SFF technology seeded a series of new possibilities and new advantages that could be exploited in the manufacturing domain, and as a result drove design for rapid manufacturing principles even further apart from conventional design for manufacture and assembly philosophy. In this study the impact that rapid manufacture had on the conventional product development process and conventional design for manufacture and assembly guidelines were investigated. This investigation brought to light the inherent strengths and weaknesses of SFF, as well as the design for manufacture and assembly guidelines that became invalid, and consequently lead directly to the characterization of a set of design for rapid manufacture guidelines.
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Gibson, I., Y. Liu, M. M. Savalani, and L. K. Anand. "Composites in rapid prototyping." Journal for New Generation Sciences, Vol 7, Issue 3: Central University of Technology, Free State, Bloemfontein, 2009. http://hdl.handle.net/11462/540.
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Published ArticleThis paper looks at the development of composite materials in layered manufacturing. It is known that Rapid Prototyping (RP) using a single material compares poorly with other conventional manufacturing processes when making parts from similar materials. For example, injection moulded parts are over 30% stronger than RP fabricated parts of the same material. The incorporation of secondary materials can result in a composite that can improve this situation. This paper will discuss different composites that are commercially available as well as some into which research is being conducted. An advantage of RP is that composites do not have to be manufactured in a homogeneous manner. Functionally graded parts may be fabricated where reinforcing material can be added in appropriate locations and in required orientations.
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Aliakbari, Mina. "Additive Manufacturing: State-of-the-Art, Capabilities, and Sample Applications with Cost Analysis." Thesis, KTH, Industriell produktion, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103598.
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Additive Manufacturing – AM – which is a part of a generic term, Rapid Prototyping, comprises a family of different techniques to build 3D physical objects sequentially stacking a series of layers over each other. These techniques have been evolving over three decades with more materials available, improving the techniques as well as generating new ones. However they are all based on the same explained idea. In this research the main AM methods followed with the opportunities of application and cost drivers is sought. For this purpose, after reviewing different processes and techniques, the application of them in diverse industry sectors is described. The influence of AM in production systems, so called Rapid Manufacturing (RM) is also discussed in terms of lean and agile concepts. Time and cost are the most important factors for the production systems to be responsive and productive respectively. Thus, case based application of RM is evaluated to clarify how AM acts in different production systems regarding these factors. To decide which method is the best, strongly depends on the case. But what has been derived from the analysis, is that however in comparison with traditional methods, AM applies more economically in one-off jobbing, yet the economy of scale exists to some extent. In fact it depends on the machine capacity utilization as well as batch size which indicates the machine volume usage. Despite all the improvements in the last three decades, the application of AM is still not widespread. Since the demand, use, applications and materials as well as its techniques are still in a growing phase, a brighter future is seen for the upcoming customer oriented market.Additive Manufacturing – AM – som är del av en generell term, Rapid Prototyping, består av en familj olika tekniker för att bygga 3D fysiska objekt genom att sekventiellt lägga lager ovanpå varandra. Dessa tekniker har utvecklats över de senaste tre decennierna, där nya material blivit tillgängliga, teknikerna har förbättrats och nya har skapats, men i slutändan bygger de alla på en och samma idé. Det projekt undersöks de huvudsakliga AM -metoderna, deras applikationer och kostnadsdrivare. Här görs först en litteraturstudie av olika tekniker och processer varefter deras användning inom olika industrier undersöks. Den influens AM har i produktionssystem, s.k. Rapid Manufacturing (RM), diskuteras också i förhållande till lean och agila koncept. Eftersom tid och kostnad är de viktigaste faktorerna för tillgänglighet respektive produktivitet utvärderas case-baserad användning av RM utifrån dessa faktorer för att förklara hur AM fungerar i produktionssystem. Att besluta vilken metod som är bäst, är starkt case-baserad. Men det som framkommit från analysen är att i jämförelse med traditionella metoder, är AM mer ekonomiskt vid enstyckstillverkning, men stordriftsfördelar finns i någon utsträckning. Faktiskt det beror på maskinens kapacitetsanvändning och satsstorlek som indikerar maskinens volymanvändning. Trots alla förbättringar under de senaste tre decennierna är användandet av AM ännu inte utbrett. Eftersom efterfrågan, användning, tillämpning och material så väl som dess tekniker fortfarande befinner sig i en tillväxtfas spås en ljusare framtid för en växande kundorienterad marknad.
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Truscott, M., G. J. Booysen, and Beer D. J. De. "Rapid prototyping and manufacturing in medical product development." Interim : Interdisciplinary Journal, Vol 8, Issue 2: Central University of Technology Free State Bloemfontein, 2009. http://hdl.handle.net/11462/373.
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Published ArticleRP and recently RM have been key factors in the development of the manufacturing industry in assisting in the development of new products. Fortunately, the application of these technologies has been realised in the medical industry. Surgeons all over the world use physical models created from CT or MRI data using some sort of additive manufacturing. The fabrication of these models has exploded into a popular research area combining engineering, material and medical expertise. Long-term growth in the additive fabrication industry will come from designs that are difficult, time-consuming, costly, or impossible to produce using standard techniques. Growth will occur with advances in current additive processes which are coupled with breakthroughs in new materials. The applications of RP and RM are as diverse as the medical issues that arise. RM of custom design medical prostheses proves to be economically viable solution, not only because it is faster to produce but it gives the designer freedom of creation too. The paper discusses some interesting medical case studies.
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Barnard, L. J., G. J. Booysen, and Beer D. J. De. "Gynaecological product development facilitated through RP and Rapid Tooling." Interim : Interdisciplinary Journal, Vol 4, Issue 1: Central University of Technology, Free State, Bloemfontein, 2005. http://hdl.handle.net/11462/422.
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Published ArticleAtkinson distinguishes between four types of prototypes, categorised through its end-use: •Design or aesthetic prototypes •Geometrical prototypes •Functional prototypes •Technological prototypes Shigley and Mitchell define the design process according to the following six phases: Recognition of need Definition of problem Synthesis Analysis and optimization Evaluation Presentation The Centre for Rapid Prototyping and Manufacture (CRPM) of the Central University of Technology, Free State was asked to assist in the development of a newly developed gynaecological cream applicator. Apart from needing a freeform fabrication system to give form fit and function to the very complex design, the product needed Rapid Tooling / Rapid Manufacturing support to enable a first batch production for medical trials and evaluation. The paper will describe the total product development process alongside prototype categories described by Atkinson and design phases defined by Shigley and Mitchell (including some iterations enabled through timeous prototyping, including various Rapid Prototyping (RP) Technologies, soft tooling and vacuum casting). More importantly, results from Rapid Tooling for limited run production (due to the complexity of the product the cycle time of the Prototype Tool is fairly long), as well as the economical impact made possible through the support of CAD / CAM and RP Technologies, will be discussed.
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Tuomi, J., and J. Karjalainen. "Cost model for rapid manufacturing." Journal for New Generation Sciences, Vol 4, Issue 1: Central University of Technology, Free State, Bloemfontein, 2006. http://hdl.handle.net/11462/493.
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Published ArticleAt Helsinki University of Technology rapid prototyping, rapid tooling and rapid manufacturing technologies and applications have been researched since late 1980s. The Integrated Design and Manufacturing research group has concentrated on new industrial Rapid Prototyping and Manufacturing (RP&M) applications within product development and manufacturing. This paper is based on research projects realized in 2001 - 2004 in cooperation with several industrial companies. New developments within industrial product development paradigms and processes will be discussed. The paper attempts to link current industrial management sciences research with latest developments within rapid manufacturing technologies. Product platforms, product customization and networked manufacturing have become common product development management paradigms in many industrial sectors. These paradigms have lead to an increasing number of product configurations and variations. Traditionally cost comparisons between RP&M processes and conventional manufacturing processes have been based on break even point calculations. The latest product development and manufacturing paradigms places agility in production and efficient prototyping technologies among others in an important role. Conventional cost per part comparison methods to value rapid manufacturing need to be re-engineered. In those comparisons the first break even point does not describe the overall rapid manufacturing economy. For example, effects of neccesity for product change, tool wear or tool defect have to be taken into consideration. In this paper the new cost modeling technology and some industrial case studies will be described.
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Dimitrov, D., P. A. Hugo, and B. Deez. "Suitability of layer manufacturing technologies for rapid tooling development in investment casting of light metals." Journal for New Generation Sciences, Vol 8, Issue 2: Central University of Technology, Free State, Bloemfontein, 2010. http://hdl.handle.net/11462/558.
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Published ArticleRapid tooling (RT) in the context of this research presents the possibility of improving the traditional investment casting process by shortening lead times while still maintaining affordable costs and required quality. Various rapid prototyping processes are available that can be used to create direct metal, polymer or wooden dies for this casting technology. This paper presents results gained in an AMTS project, focusing on RT development for investment casting of light metals. One of the most widely used layer manufacturing processes available in South Africa is selective laser sintering. A machine produced by the German manufacturer EOS (process known as laser sintering) utilising this technology was selected for the study. Two of the materials that are suitable for rapid die making are used, which in tum reflects different mechanical properties and process economics. A standard benchmark part was used as a study base. Two dies were built, one in alumide and one in polyamide. A comprehensive measurement programme was conducted, followed by an appropriate statistical analysis and evaluation regarding accuracy and surface finish. A number of wax patterns were produced. The best wax patterns from each die were selected and evaluated. The subsequently produced castings in AI, Mg and TI were further examined and evaluated. Various issues concerning the reinforcement, wax injection, pattern removal, accuracy and surface finish of the dies are discussed in the paper. The research concludes that rapid tooling techniques can be successfully used for creating accurate dies in order to shorten lead times in the investment casting process chain.
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ZafarUllahh, Usman, and Cheema Zaman Zafar. "A Theoretical Evaluation of Commercially Available Tool Chain for Rapid Prototyping of Wireless Communication Systems." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2393.
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Using Moore’s Law, engineers and scientists have ability to place smart and powerful IC devices,
with increasingly complex systems on a chip (SoC). This thesis describes the technology of rapid
prototyping in the field of communication systems. Reconfigurable technologies always help in the
construction of flexible systems (where hardware and software can be changed at any time during its
execution). With growing developments in the field of communication systems, DSP is now the
heart of every communication system; engineers are consequently looking for a smart and reliable
platform to enhance their production to meet future challenges. This thesis presents a DSP-based
theoretical survey of rapid prototyping in communication systems. An attempt has been made to
cover every prototype issue in this theoretical survey. The objective is to make an evaluation to
judge whether it is feasible for practical educational and research purposes. The test design proposed
in this thesis for the evaluation is a simple DSP-based Correlator.
Scientists and engineers are looking for a smart system which can provide end results, in order to be
implemented in practical, real time environments and for research and educational purposes in
universities.
Previously we needed to make a hardware PCB for algorithm testing, especially when we had
complex algorithms which involved a great deal of work, but with the help of this thesis and other
research projects this area of rapid prototyping we are beginning to make some progress in the right
direction.
The tool chain plays a key role for the development in terms of the evaluation of rapid prototyping in
communication systems. Currently the available methods to design a system require a great deal of
time and money along with the efforts of many skilled researchers. Rapid prototyping is a shortcut
with regards to these usual methods with appropriate tools to achieve the goal.
In this thesis our main focus is on MATLAB, SIMULINK, REAL TIME WORKSHOP and the
appropriate Texas Instruments products (Code Composer Studio and Target DSP), to achieve
maximum performance and reduction of development time. The tools which are discussed are
actively involved in the design process of systems using the rapid prototyping development
technique. The basic system design is conducted using the model based on the design of tools in
Math Works software, consisting of MATLAB and SIMULINK using their tool and block sets.
Using these tools many applications for educational purposes and on a commercial level have been
implemented [2]. Here a DSP application, an FFT-based (Fast Fourier Transform) Correlator is
proposed that measures the phase delay of the two transmitted base band signals that are sampled at
different rates. Four major phases are involved for the purposes of rapid prototyping : 1) - the system
algorithm is designed and implemented in MATLAB and SIMULINK, 2) – generation of the
standard ANSI C code for this designed model has been done by using REAL TIME WORK SHOP,
3)- implementation of this C code on DSP/Microprocessor-based hardware using an interface and
4)- carrying out a performance evaluation of this tool chain, i.e. whether it is feasible for practical,
commercial and educational research purposes, and how these developments are overcoming the
barriers for the implementation of DSP algorithms in communication systems for commercial and
educational use. The tool chain acts as a bridge in between the input resources and output results
after implementation on hardware. Chapter 1 presents an overview of the thesis. Chapter 2 describes
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the main tools involved in the rapid prototyping revolution. Chapter 3 describes the role of every
tool in the flow of rapid prototyping processes. Chapter 4 provides an overview of the previously
implemented systems using rapid tool chains, their results and our proposed model and
recommendations. Chapter 5 concludes the results grasped from the previously implemented tool
chains and theoretical survey made in this thesis.
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Steinberger, Jürgen. "Optimierung des Selektiven-Laser-Sinterns zur Herstellung von Feingußteilen für die Luftfahrtindustrie /." Düsseldorf : VDI-Verl, 2001. http://www.gbv.de/dms/bs/toc/328089400.pdf.
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Chen, Zhe, and 陈哲. "Selection of optimal build orientation with minimum strain and maximumstrength in rapid prototyping." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45590977.
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Franck, Christopher G. "Assessing the value of rapid prototyping and rapid tooling in product development processes." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16970.
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Baldauf, Alicia B., and Jason Reherman. "Increasing responsiveness of the Army Rapid Acquisition Process: the Army Rapid Equipping Force." Monterey, California. Naval Postgraduate School, 2011. http://hdl.handle.net/10945/10753.
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This Joint Applied Project examines the U.S. Army Rapid Equipping Force (REF) processes, practices and lessons learned for fulfilling emerging urgent needs in the current Overseas Contingency Operations (OCO). It compares Army rapid acquisition policies and processes to the execution of a traditional Urgent Materiel Release (UMR) program to identify opportunities to improve the responsiveness of rapid acquisition programs executed by traditional program management offices. The project establishes a baseline and analyzes the implications of existing policies, processes, and practices for executing rapid acquisition programs. It draws conclusions and offers recommendations for continuing improvements towards a more modern and responsive rapid acquisition process. The findings indicate that the Army REF is adapting and evolving processes to better respond to the urgent needs of its operational commanders and the warfighter that can be applied by traditional acquisition organizations.