165 research outputs found
Process and machine system development for the forming of miniature/micro sheet metal products
This paper reports on the current development of the process for the forming of thin sheet-metal micro-parts (t < 50µm) and the corresponding machine system which is part of the research and technological development of an EU funded integrated project - MASMICRO ("Integration of Manufacturing Systems for the Mass-Manufacture of Miniature/Micro-Products" (/www.masmicro.net/). The process development started with qualification of the fundamentals related to the forming of thin sheet-metals in industrial environment, for which a testing machine and several sets of the testing tools were developed. The process was further optimised, followed by new tool designs. Based on the experience gained during the process development, a new forming press which is suitable for industrial, mass-customised production, has been designed
Development of a new machine system for the forming of micro-sheet-products
Most of the developed micro-forming machines were based on standalone concepts which do not support efficient integration to make them fully automated and integrated. At present, material feeding in micro-forming is not of sufficient precision and reliability for high throughput manufacturing applications. Precise feeding is necessary to ensure that micro-parts can be produced with sufficient accuracy, especially in multi-stage forming, while high-speed feeding is a must to meet the production-rate requirements. Therefore, design of a new high-precision and high-speed feeder for micro-forming is proposed. Several possible approaches are examined with a view to establishing feasible concepts. Based on the investigation, several concepts for thin sheet-metal feeding for micro-forming are generated, they being argued and assessed with applicable loads and forces analysis. These form a basis of designing a new feeder
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Endogenous agendas and seniority advantage
We study a legislative assembly that chooses its agenda protocol endogenously. We generalize McKelvey and Riezman’s (1992) seminal theory on seniority in legislatures, by allowing for a large class of ordinal agenda rules that assign different recognition probability to each legislator. We consider two stages — the selection of agenda rules, and the decision making that transpires under them. We predict that the agenda rules chosen in equilibrium preserve seniority distinctions, disproportionately favor more senior legislators, and generate an incumbency advantage to all legislators.Governmen
Viagem à Índia para prospecção de tecnologias sobre mamona e pinhão manso.
Viagem á ĂŤndia para prospecção de tecnologias sobre mamona e pinhĂŁo manso ; Introdução; Roteiro; Detalhamento; Sardar Krushinagar Dantiwada University; Pesquisas com mamona; Pesquisas com pinhĂŁo manso; Outras oleaginosas ; IndĂşstria de extração de Ăłleo de mamona ; Mercado de leilões para comercialização de produtos agrĂcolas ; Mini-usina de biodiesel de pinhĂŁo manso; 4Âş Seminário Internacional sobre semente e Ăłleo de mamona e produtos de valor agregado ; Visita Ă Secretaria de Agricultura do Estado de Tamil Nadu ; Projeto MGR jatropha biodiesel ; Loco Works - Empresa operadora de ferrovias ; Exposição sobre a mini-usina de biodiesel da Empresa Loco Works ; Considerações finais; PinhĂŁo manso ; Mamona.bitstream/CNPA/18319/1/DOC153.pd
Efficiency Improvement and Analysis of Changes in Microstructure Associated to a Uniform Pressure Actuator
During the 1st international Conference on HIGH SPEED FORMING held in Dortmund in 2004 a new forming coil giving significant advantages was presented in the framework of ongoing R&D programs at OSU (The Ohio State University). It established the improvement provided by the return path for currents induced in the workpiece. To quantify the mentioned improvement, Labein has performed classical cone forming experiments with both configurations and analyzed energetic efficiency using well known alloys, more precisely AA 6016 and 1050. Both deformation mechanisms and contour analysis of the specimens were studied. General purpose multi-turn coils provide pressure distributions not extended to the whole forming area, resulting in zones undergoing significant delay as die the deformation sequence is referred. As a result, varied deformation patterns can be found along the contour of a cone specimen formed in such way. Firstly, a macroscopic survey of the specimens shows that uniform pressure distributes deformation over the entire formed area during the deformation process. Secondly, the effect on efficiency provided by this new coil concept is focuses not only on the ability for distributing deformation, but on the energy required to create such deformation. Finally, to validate the whole simulation, the predicted strain level, shape, and internal energy of the workpiece are compared with the experimental specimens. A key point in the validation process is checking the internal energy. It is known that the ratio of stored energy to deformation energy ranges in the order of 30 %. The procedure for the experiments follows this methodology
Aerosol Production with Surgical Instrumentation: Implications for Head and Neck Surgery in the COVID-19 Era
Evaluating the aerosolization of droplets from surgical instruments to assess the implications of surgery in SARS-CoV-2 transmission for both patients and providers. Cadaver study. Outpatient surgery center. Aerosolized particles between 0.3 and 25 microns were measured. Instruments tested included monopolar cautery with and without suction, bipolar cautery, a bipolar vessel sealing device, and tissue scissors. Each trial was compared to a background reading. Monopolar cautery without suction, Ligasure used continuously and Bipolar cautery produced the most aerosols. Monopolar cautery with simultaneous suction produced no detectable aerosols. Ligasure used for a single cycle produced notably fewer aerosols than during continuous use. Most aerosols produced were \u3c 5 microns. These data support n95 use during surgical management of the upper aerodigestive tract, as well as the use of suction in the surgical field
Proprotein convertases blockage up-regulates specifically metallothioneins coding genes in human colon cancer stem cells
ABSTRACT: Despite continuous exertion made, colon cancer still represents a major health problem and its incidence continues being high worldwide. There is growing evidence in support of the cancer stem cells (CSCs) being central in the initiation of this cancer, and CSCs have been the focus of various studies for the identification of new ways of treatment. Lately, the proprotein convertases (PCs) were reported to regulate the maturation and expression of various molecules involved in the malignant phenotype of colon cancer cells, however, the identity of the molecules regulated by these serine proteases in CSCs is unknown. In this study, we used the general PCs inhibitor, the Decanoyl-RVKR-chloromethylketone (Decanoyl-RVKR-CMK) that inhibits all the PCs found in the secretory pathway, and analyzed its effect on CSCs using RNA-seq analysis. Remarkably, from the only 9 upregulated genes in the human SW620-derived sphere-forming cells, we identified 7 of the 11 human metallothioneins, all of them localized on chromosome 16, and zinc related proteins as downstream effectors of the PCs. The importance of these molecules in the regulation of cell proliferation, differentiation and chemoresistance, and their reported potential tumor suppressor role and loss in colon cancer patients associated with worse prognosis, suggests that targeting PCs in the control of the malignant phenotype of CSCs is a new potential therapeutic strategy in colon cancer
Intermediate Vancomycin Susceptibility in a Community-associated MRSA Clone
We describe a case of treatment failure caused by a strain of USA300 community-associated methicillin-resistant Staphylococcus aureus (MRSA) with intermediate susceptibility to vancomycin and reduced susceptibility to daptomycin. The strain was isolated from the bone of a 56-year-old man with lumbar osteomyelitis after a 6-week treatment course of vancomycin for catheter-associated septic thrombophlebitis
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