971 resultados para - Rapid Manufacturing
Resumo:
India’s desire to transform itself into an international military power has brought about a rapid shift in its approach to procuring military hardware. The indigenization of India’s military manufacturing capacity forms an integral part of the strategic objectives of Indian military services, with its realization being a function of significant government investment in strategic technologies. This has a number of ramifications. An indigenous Indian military capacity, particularly in the field of aviation, forms a key part of India’s ambition of achieving regional air superiority, or even supremacy, and being capable of power projection. This is particularly in response to China’s increasing presence in South Asian airspace. A burgeoning Indian military manufacturing machine based on a comparative advantage in skilled technicians and lower-cost labour, together with strategic collaboration with foreign military hardware manufacturers, may also lead to neighbouring countries looking to India as a source of competitively priced military hardware. In short, this chapter seeks to analyse the rationale behind India’s attempt to become militarily self-sufficient in the field of aviation, discuss the technical, economic and political context in which it is achieving this transformation, and assess the potential outlook of success for India’s drive to achieve self-sufficiency in the arena of military aviation. This chapter will do so by using the case of India’s attempt to develop a fifth-generation fighter aircraft.
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Microwell platforms are frequently described for the efficient and uniform manufacture of 3-dimensional (3D) multicellular microtissues. Multiple partial or complete medium exchanges can displace microtissues from discrete microwells, and this can result in either the loss of microtissues from culture, or microtissue amalgamation when displaced microtissues fall into common microwells. Herein we describe the first microwell platform that incorporates a mesh to retain microtissues within discrete microwells; the microwell-mesh. We show that bonding a nylon mesh with an appropriate pore size over the microwell openings allows single cells to pass through the mesh into the microwells during the seeding process, but subsequently retains assembled microtissues within discrete microwells. To demonstrate the utility of this platform, we used the microwell-mesh to manufacture hundreds of cartilage microtissues, each formed from 5 × 10(3) bone marrow-derived mesenchymal stem/stromal cells (MSC). The microwell-mesh enabled reliable microtissue retention over 21-day cultures that included multiple full medium exchanges. Cartilage-like matrix formation was more rapid and homogeneous in microtissues than in conventional large diameter control cartilage pellets formed from 2 × 10(5) MSC each. The microwell-mesh platform offers an elegant mechanism to retain microtissues in microwells, and we believe that this improvement will make this platform useful in 3D culture protocols that require multiple medium exchanges, such as those that mimic specific developmental processes or complex sequential drug exposures.
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We and others have published on the rapid manufacture of micropellet tissues, typically formed from 100-500 cells each. The micropellet geometry enhances cellular biological properties, and in many cases the micropellets can subsequently be utilized as building blocks to assemble complex macrotissues. Generally, micropellets are formed from cells alone, however when replicating matrix-rich tissues such as cartilage it would be ideal if matrix or biomaterials supplements could be incorporated directly into the micropellet during the manufacturing process. Herein we describe a method to efficiently incorporate donor cartilage matrix into tissue engineered cartilage micropellets. We lyophilized bovine cartilage matrix, and then shattered it into microscopic pieces having average dimensions < 10 μm diameter; we termed this microscopic donor matrix "cartilage dust (CD)". Using a microwell platform, we show that ~0.83 μg CD can be rapidly and efficiently incorporated into single multicellular aggregates formed from 180 bone marrow mesenchymal stem/stromal cells (MSC) each. The microwell platform enabled the rapid manufacture of thousands of replica composite micropellets, with each micropellet having a material/CD core and a cellular surface. This micropellet organization enabled the rapid bulking up of the micropellet core matrix content, and left an adhesive cellular outer surface. This morphological organization enabled the ready assembly of the composite micropellets into macroscopic tissues. Generically, this is a versatile method that enables the rapid and uniform integration of biomaterials into multicellular micropellets that can then be used as tissue building blocks. In this study, the addition of CD resulted in an approximate 8-fold volume increase in the micropellets, with the donor matrix functioning to contribute to an increase in total cartilage matrix content. Composite micropellets were readily assembled into macroscopic cartilage tissues; the incorporation of CD enhanced tissue size and matrix content, but did not enhance chondrogenic gene expression.
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In this paper, we report on the realisation of a free space deposition process (FSD). For the first time the use of a moving support structure to deposit tracks of metal starting from a substrate and extending into free space is characterised. The ability to write metal shapes in free space has wide ranging applications in additive manufacturing and rapid prototyping where the tracks can be layered to build overhanging features without the use of fixed support structures (such as is used in selective laser melting (SLM) and stereo lithography (SLA)). We demonstrate and perform a preliminary characterisation of the process in which a soldering iron was used to deposit lead free solder tracks. The factors affecting the stability of tracks and the effect of operating parameters, temperature, velocity, initial track starting diameter and starting volume were measured. A series of 10 tracks at each setting were compared with a control group of tracks; the track width, taper and variation between tracks were compared. Notable results in free space track deposition were that the initial track diameter and volume affected the repeatability and quality of tracks. The standard deviation of mean track width of tracks from the constrained initial diameter group were half that of the unconstrained group. The amount of material fed to the soldering iron before commencing deposition affected the taper of tracks. At an initial volume of 7 mm3 and an initial track diameter of 0.8 mm, none of the ten tracks deposited broke or showed taper > ∼1°. The maximum deposition velocity for free space track deposition using lead-free solder was limited to 1.5 mm s-1. © 2011 Elsevier B.V. All rights reserved.
Resumo:
Ellis, D. I., Broadhurst, D., Kell, D. B., Rowland, J. J., Goodacre, R. (2002). Rapid and quantitative detection of the microbial spoilage of meat by Fourier Transform Infrared Spectroscopy and machine learning. ? Applied and Environmental Microbiology, 68, (6), 2822-2828 Sponsorship: BBSRC
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A área da simulação computacional teve um rápido crescimento desde o seu apareciment, sendo actualmente uma das ciências de gestão e de investigação operacional mais utilizadas. O seu princípio baseia-se na replicação da operação de processos ou sistemas ao longo de períodos de tempo, tornando-se assim uma metodologia indispensável para a resolução de variados problemas do mundo real, independentemente da sua complexidade. Das inúmeras áreas de aplicação, nos mais diversos campos, a que mais se destaca é a utilização em sistemas de produção, onde o leque de aplicações disponível é muito vasto. A sua aplicação tem vindo a ser utilizada para solucionar problemas em sistemas de produção, uma vez que permite às empresas ajustar e planear de uma maneira rápida, eficaz e ponderada as suas operações e os seus sistemas, permitindo assim uma rápida adaptação das mesmas às constantes mudanças das necessidades da economia global. As aplicações e packages de simulação têm seguindo as tendências tecnológicas pelo que é notório o recurso a tecnologias orientadas a objectos para o desenvolvimento das mesmas. Este estudo baseou-se, numa primeira fase, na recolha de informação de suporte aos conceitos de modelação e simulação, bem como a respectiva aplicação a sistemas de produção em tempo real. Posteriormente centralizou-se no desenvolvimento de um protótipo de uma aplicação de simulação de ambientes de fabrico em tempo real. O desenvolvimento desta ferramenta teve em vista eventuais fins pedagógicos e uma utilização a nível académico, sendo esta capaz de simular um modelo de um sistema de produção, estando também dotada de animação. Sem deixar de parte a possibilidade de integração de outros módulos ou, até mesmo, em outras plataformas, houve ainda a preocupação acrescida de que a sua implementação recorresse a metodologias de desenvolvimento orientadas a objectos.
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Depuis la révolution industrielle, l’évolution de la technologie bouleverse le monde de la fabrication. Aujourd'hui, de nouvelles technologies telles que le prototypage rapide font une percée dans des domaines comme celui de la fabrication de bijoux, appartenant jadis à l'artisanat et en bouscule les traditions par l'introduction de méthodes plus rapides et plus faciles. Cette recherche vise à répondre aux deux questions suivantes : - ‘En quoi le prototypage rapide influence-t-il la pratique de fabrication de bijoux?’ - ‘En quoi influence-t-il de potentiels acheteurs dans leur appréciation du bijou?’ L' approche consiste en une collecte de données faite au cours de trois entretiens avec différents bijoutiers et une rencontre de deux groupes de discussion composés de consommateurs potentiels. Les résultats ont révélé l’utilité du prototypage rapide pour surmonter un certain nombre d'obstacles inhérents au fait-main, tel que dans sa géométrie, sa commercialisation, et sa finesse de détails. Cependant, il se crée une distance entre la main du bijoutier et l'objet, changeant ainsi la nature de la pratique. Cette technologie est perçue comme un moyen moins authentique car la machine rappelle la production de masse et la possibilité de reproduction en série détruit la notion d’unicité du bijou, en réduisant ainsi sa charge émotionnelle. Cette recherche propose une meilleure compréhension de l'utilisation du prototypage rapide et de ses conséquences dans la fabrication de bijoux. Peut-être ouvrira-t-elle la voie à une recherche visant un meilleur mariage entre cette technique et les méthodes traditionnelles.
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This paper addresses the feasibility of implementing Japanese manufacturing systems in the United States. The recent success of Japanese transplant companies suggests that Just-In-Time (JIT) production is possible within America's industrial environment. Once American workers receive proper training, they have little difficulty participating in rapid setup procedures and utilizing the kanban system. Japanese transplants are gradually developing Japanese-style relationships with their American supplier companies by initiating long-term, mutually beneficial agreements. They are also finding ways to cope with America's problem of distance, which is steadily decreasing as an obstacle to JIT delivery. American companies, however, encounter Significant problems in trying to convert traditionally organized, factories to the JIT system. This paper demonstrates that it is both feasible and beneficial for American manufacturers to implement JIT production techniques. Many of the difficulties manufacturers experience center around a general lack of information about JIT. Once a company realizes its potential for setup-time reduction, a prerequisite for the JIT system, workers and managers can work together to create a new process for handling equipment changeover. Significant results are possible with minimal investment. Also, supervisors often do not realize that the JIT method of ordering goods from suppliers is compatible with current systems. This "kanban system" not only enhances current systems but also reduces the amount of paperwork and scheduling involved. When arranging JlT delivery of supplier goods, American manufacturers tend to overlook important aspects of JIT supplier management. However, by making long-tenn commitments, initiating the open exchange of information, assisting suppliers in reaching new standards of performance, increasing the level of conununication, and relying more on suppliers' engineering capabilities, even American manufacturers can develop Japanese-style supplier relationships that enhance the effectiveness of the system.
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This thesis is composed of three life-cycle analysis (LCA) studies of manufacturing to determine cumulative energy demand (CED) and greenhouse gas emissions (GHG). The methods proposed could reduce the environmental impact by reducing the CED in three manufacturing processes. First, industrial symbiosis is proposed and a LCA is performed on both conventional 1 GW-scaled hydrogenated amorphous silicon (a-Si:H)-based single junction and a-Si:H/microcrystalline-Si:H tandem cell solar PV manufacturing plants and such plants coupled to silane recycling plants. Using a recycling process that results in a silane loss of only 17 versus 85 percent, this results in a CED savings of 81,700 GJ and 290,000 GJ per year for single and tandem junction plants, respectively. This recycling process reduces the cost of raw silane by 68 percent, or approximately $22.6 and $79 million per year for a single and tandem 1 GW PV production facility, respectively. The results show environmental benefits of silane recycling centered around a-Si:H-based PV manufacturing plants. Second, an open-source self-replicating rapid prototype or 3-D printer, the RepRap, has the potential to reduce the environmental impact of manufacturing of polymer-based products, using distributed manufacturing paradigm, which is further minimized by the use of PV and improvements in PV manufacturing. Using 3-D printers for manufacturing provides the ability to ultra-customize products and to change fill composition, which increases material efficiency. An LCA was performed on three polymer-based products to determine the CED and GHG from conventional large-scale production and are compared to experimental measurements on a RepRap producing identical products with ABS and PLA. The results of this LCA study indicate that the CED of manufacturing polymer products can possibly be reduced using distributed manufacturing with existing 3-D printers under 89% fill and reduced even further with a solar photovoltaic system. The results indicate that the ability of RepRaps to vary fill has the potential to diminish environmental impact on many products. Third, one additional way to improve the environmental performance of this distributed manufacturing system is to create the polymer filament feedstock for 3-D printers using post-consumer plastic bottles. An LCA was performed on the recycling of high density polyethylene (HDPE) using the RecycleBot. The results of the LCA showed that distributed recycling has a lower CED than the best-case scenario used for centralized recycling. If this process is applied to the HDPE currently recycled in the U.S., more than 100 million MJ of energy could be conserved per annum along with significant reductions in GHG. This presents a novel path to a future of distributed manufacturing suited for both the developed and developing world with reduced environmental impact. From improving manufacturing in the photovoltaic industry with the use of recycling to recycling and manufacturing plastic products within our own homes, each step reduces the impact on the environment. The three coupled projects presented here show a clear potential to reduce the environmental impact of manufacturing and other processes by implementing complimenting systems, which have environmental benefits of their own in order to achieve a compounding effect of reduced CED and GHG.
Resumo:
Generative Verfahren sind seit etwa 1987 in den USA und seit etwa 1990 in Europa und Deutschland in Form von Rapid Prototyping Verfahren bekannt und haben sich in dieser Zeit von eher als exotisch anzusehenden Modellbauverfahren zu effizienten Werkzeugen für die Beschleunigung der Produktentstehung gewandelt. Mit der Weiterentwicklung der Verfahren und insbesondere der Materialien wird mehr und mehr das Feld der direkten Anwendung der Rapid Technologie zur Fertigung erschlossen. Rapid Technologien werden daher zum Schlüssel für neue Konstruktionssystematiken und Fertigungsstrategien. Die Anwendertagung Rapid.Tech befasst sich mit den neuen Verfahren zur direkten Produktion und den daraus erwachsenden Chancen für Entwickler und Produzenten. Die Kenntnis der Rapid Prototyping Verfahren wird bei den meisten Fachvorträgen auf der Rapid.Tech vorausgesetzt. Für diejenigen, die sich bisher mit generativen Verfahren noch nicht beschäftigt haben, oder die ihre Grundkenntnisse schnell auffrischen wollen, haben wir die folgenden Zusammenfassung der Grundlagen der generativen Fertigungstechnik, der heutigen Rapid Prototyping Verfahren, zusammengestellt.