499 resultados para plc opc
Resumo:
Resumen basado en el de la publicaci??n
Resumo:
Resumen basado en el de la publicaci??n
Resumo:
Resumen basado en el de la publicaci??n
Resumo:
Resumen basado en el de la publicaci??n
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La finalitat del projecte és realitzar l’automatització dels sis processos d’una fàbrica de pinsos d’una cooperativa agrícola: entrada de matèries, mòlta, dosificació amb correcció, barreja, granulació i sortida de pinsos. Per controlar tots els processos es desenvolupa un PLC amb el corresponent programa d’autòmat; se seleccionen els diferents sensors i preactivadors necessaris que s’hauran d’incorporar per poder transformar la lògica rígida de contactors a una de flexible; se selecciona un sistema Scada per a la interfície d’usuari, i es dissenya la instal·lació elèctrica corresponent, per tal de poder implementar aquest automatisme en la línia de producció
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O sistema educativo e formativo português tem vindo a mudar significativamente, devido ao fenómeno da globalização e às exigências da sociedade do conhecimento. Com efeito, os desafios de uma economia mais dinâmica e competitiva, baseada no conhecimento requerem a definição de novas políticas educativas. Os objetivos de aumentar a equidade e a oportunidade de educação para todos os alunos e de combater o abandono e o insucesso escolar conduziram à implementação, em Portugal, de algumas medidas que envolvam os jovens em programas de formação, tais como os cursos de educação e formação (CEF). É no seio deste novo e complexo contexto educativo que colocamos a relevante questão: como podem as equipas pedagógicas dos cursos de educação e formação responder, adequadamente, às exigências de atuação neste tipo de percurso diversificado de formação? A natureza dos constantes constrangimentos que os professores enfrentam permitiu-nos concluir que estes têm de trabalhar sobre a sua própria capacidade de mudança, de forma a responderem a todas estas crescentes demandas, pelo que, neste sentido, a mudança assume-se como uma extraordinária oportunidade de desenvolvimento profissional. Esta construção de capacidade ou reculturing (Fullan, 2007) é o resultado de várias adaptações e decisões, tomadas pelos professores, colaborativamente como comunidades de aprendizagem profissional (CAP). Na verdade, nas CAP os docentes estão moral e intelectualmente comprometidos com a melhoria, a inovação e a sustentabilidade da educação, por conseguinte elas não são apenas um meio de melhorar os resultados dos alunos e de aumentar as suas aprendizagens, como são, também, o processo mais eficaz de implicar os docentes no desenvolvimento profissional contínuo, profundamente ligado à ação. Consequentemente, no sentido de transformar as equipas pedagógicas em comunidades de aprendizagem profissional apresentamos um projeto de formação que se concretizará através da implementação de um círculo de estudos, no contexto escolar, que pretende assegurar o desenvolvimento e a atualização dos conhecimentos e competências dos professores dos CEF e melhorar a qualidade e eficácia da aprendizagem e da prática docente. As expectativas em relação aos resultados desta formação são bastante elevadas e alicerçam-se na recetividade e disponibilidade demonstradas, por todos os professores dos CEF, para participarem neste projeto de formação.
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Integrin-linked kinase (ILK) has been implicated in the regulation of a range of fundamental biological processes such as cell survival, growth, differentiation, and adhesion. In platelets ILK associates with beta 1- and beta 3-containing integrins, which are of paramount importance for the function of platelets. Upon stimulation of platelets this association with the integrins is increased and ILK kinase activity is up-regulated, suggesting that ILK may be important for the coordination of platelet responses. In this study a conditional knockout mouse model was developed to examine the role of ILK in platelets. The ILK-deficient mice showed an increased bleeding time and volume, and despite normal ultrastructure the function of ILK-deficient platelets was decreased significantly. This included reduced aggregation, fibrinogen binding, and thrombus formation under arterial flow conditions. Furthermore, although early collagen stimulated signaling such as PLC gamma 2 phosphorylation and calcium mobilization were unaffected in ILK-deficient platelets, a selective defect in alpha-granule, but not dense-granule, secretion was observed. These results indicate that as well as involvement in the control of integrin affinity, ILK is required for alpha-granule secretion and therefore may play a central role in the regulation of platelet function. (Blood. 2008; 112: 4523-4531)
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Objective - Platelet stimulation by collagen and collagen-related peptides (CRPs) is associated with activation of protein tyrosine kinases. In the present study, we investigated the role of Src family tyrosine kinases in the initial adhesion events of human platelets to collagen and cross-linked CRP. Methods and Results - Under arterial flow conditions, a glycoprotein VI - specific substrate, cross-linked CRP, caused rapid (<2 second) platelet retention and protein tyrosine phosphorylation that were markedly decreased by the Src family kinase inhibitor pyrozolopyrimidine (PP2) or by aggregation inhibitor GRGDSP. CRP-induced platelet retention was transient, and 90% of single platelets or aggregates detached within seconds. PP2, although having no effect on RGD peptide-binding to CRP, completely blocked aggregation and tyrosine phosphorylation of Syk and phospholipase Cγ2 (PLCγ2). In contrast, PP2 weakly (<30%) suppressed firm adhesion to collagen mediated primarily by the alpha(2)beta(1) integrin. Although PP2 prevented activation of Syk and PLCgamma2 in collagen-adherent platelets, tyrosine phosphorylation of several unidentified protein bands persisted, as did autophosphorylation of pp125(FAK). Conclusions - These findings indicate that activation of Src-tyrosine kinases Syk and PLCgamma2 is not required for the initial stable attachment of human platelets to collagen and for FAK autophosphorylation. However, Src-tyrosine kinases are critical for glycoprotein VI - mediated signaling leading to platelet aggregation.
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An ion-conducting polymer wherein at least 80% of the repeat units comprise an ion-conducting region and a spacer region is disclosed. The ion-conducting region has an aromatic backbone of one or more aromatic groups, wherein at least one ion-conducting functional group is attached to each aromatic group. The spacer region has an aromatic backbone of at least four aromatic groups, wherein no ion-conducting functional groups are attached to the aromatic backbone. The polymer is suitable for use as a fuel cell membrane, and can be incorporated into membrane electrode assemblies.
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A water gas shift catalyst comprising metal particles and a metal oxide material is disclosed. The metal particles comprise at least one precious metal and the metal oxide material comprises at least one reducible metal oxide. Substantially all of the metal particles are encapsulated by the metal oxide material such that the catalyst has substantially no activity for methanation. The loading of the metal particles is between 0.5-25wt% based on the weight of the metal oxide material. A process for preparing the catalyst is also disclosed.
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Purpose – To describe some research done, as part of an EPSRC funded project, to assist engineers working together on collaborative tasks. Design/methodology/approach – Distributed finite state modelling and agent techniques are used successfully in a new hybrid self-organising decision making system applied to collaborative work support. For the particular application, analysis of the tasks involved has been performed and these tasks are modelled. The system then employs a novel generic agent model, where task and domain knowledge are isolated from the support system, which provides relevant information to the engineers. Findings – The method is applied in the despatch of transmission commands within the control room of The National Grid Company Plc (NGC) – tasks are completed significantly faster when the system is utilised. Research limitations/implications – The paper describes a generic approach and it would be interesting to investigate how well it works in other applications. Practical implications – Although only one application has been studied, the methodology could equally be applied to a general class of cooperative work environments. Originality/value – One key part of the work is the novel generic agent model that enables the task and domain knowledge, which are application specific, to be isolated from the support system, and hence allows the method to be applied in other domains.
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Momentum strategies have the potential to generate extra profits in private real estate markets. Tests of a variety of frequencies of portfolio reweighting identify periods of winner and loser performance. There are strong potential gains from momentum strategies that are based on prior returns over a 6- to 12-month period. Whether these gains are attainable for real-world investors depends on transaction costs, but some momentum strategies do produce net excess returns. The findings hold even if returns are unsmoothed to reflect underlying market prices.
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Background and purpose: Molecular mechanisms underlying the links between dietary intake of flavonoids and reduced cardiovascular disease risk are only partially understood. Key events in the pathogenesis of cardiovascular disease, particularly thrombosis, are inhibited by these polyphenolic compounds via mechanisms such as inhibition of platelet activation and associated signal transduction, attenuation of generation of reactive oxygen species, enhancement of nitric oxide production and binding to thromboxane A2 receptors. In vivo, effects of flavonoids are mediated by their metabolites, but the effects and modes of action of these compounds are not well-characterized. A good understanding of flavonoid structure–activity relationships with regard to platelet function is also lacking. Experimental approach: Inhibitory potencies of structurally distinct flavonoids (quercetin, apigenin and catechin) and plasma metabolites (tamarixetin, quercetin-3′-sulphate and quercetin-3-glucuronide) for collagen-stimulated platelet aggregation and 5-hydroxytryptamine secretion were measured in human platelets. Tyrosine phosphorylation of total protein, Syk and PLCγ2 (immunoprecipitation and Western blot analyses), and Fyn kinase activity were also measured in platelets. Internalization of flavonoids and metabolites in a megakaryocytic cell line (MEG-01 cells) was studied by fluorescence confocal microscopy. Key results: The inhibitory mechanisms of these compounds included blocking Fyn kinase activity and the tyrosine phosphorylation of Syk and PLCγ2 following internalization. Principal functional groups attributed to potent inhibition were a planar, C-4 carbonyl substituted and C-3 hydroxylated C ring in addition to a B ring catechol moiety. Conclusions and implications: The structure–activity relationship for flavonoids on platelet function presented here may be exploited to design selective inhibitors of cell signalling.