A practical method for identifying intermetallic phase particles in aluminium alloys by electron probe microanalysis

Aluminium alloys that contain Si, Mg, Fe, Mn and/or Cu usually contain one or more types of intermetallic phases that are not readily distinguishable in the microstructure by conventional microscopy methods. It has thus been a challenge to develop a method that will unambiguously identify them. A practical approach has been developed that is based on an inherent linear relationship revealed for the overall distribution of any two elements in a precipitate/matrix geometry and the first-order approximation of electron probe microanalysis (EPMA) results. Application of this approach to a direct chill cast 6082 alloy is demonstrated, and its major limitations are discussed.

Columnar to equiaxed transition of eutectic in hypoeutectic aluminium-silicon alloys

Directional solidification of unmodified and strontium modified binary, high-purity aluminium-7 wt% silicon and commercial A356 alloys has been carried out to investigate the mechanism of eutectic solidification. The microstructure of the eutectic growth inter-face was investigated with optical microscopy and Electron Backscattering Diffraction (EBSD). In the commercial alloys, the eutectic solidification inter-face extends in the growth direction and creates a eutectic mushy zone. A planar eutectic growth front is observed in the high-purity alloys. The eutectic aluminium has mainly the same crystallographic orientation as the dendrites in the unmodified alloys and the strontium modified high-purity alloy. A more complex eutectic grain structure is found in the strontium modified commercial alloy. A mechanism involving constitutional undercooling and a columnar to equiaxed transition explains the differences between pure and commercial alloys. It is probably caused by the segregation of iron and magnesium and the activation of nucleants in the commercial alloy. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.

A cassette ligation strategy with thioether replacement of three Gly-Gly peptide bonds: Total chemical synthesis of the 101 residue protein early pregnancy factor [psi(CH2S)(28-29,56-57,76-77)]

The 101 residue protein early pregnancy factor (EPF), also known as human chaperonin 10, was synthesized from four functionalized, but unprotected, peptide segments by a sequential thioether ligation strategy. The approach exploits the differential reactivity of a peptide-NHCH2CH2SH thiolate with XCH2CO-peptides, where X = Cl or I/Br. Initial model studies with short functionalized (but unprotected) peptides showed a significantly faster reaction of a peptide-NHCH2CH2SH thiolate with a BrCH2CO-peptide than with a CICH2CO-peptide, where thiolate displacement of the halide leads to chemoselective formation of a thioether surrogate for the Gly-Gly peptide bond. This rate difference was used as the basis of a novel sequential ligation approach to the synthesis of large polypeptide chains. Thus, ligation of a model bifunctional N-alpha-chloroacetyl, C-terminal thiolated peptide with a second N-alpha-bromoacetyl peptide demonstrated chemoselective bromide displacement by the thiol group. Further investigations showed that the relatively unreactive N-alpha-chloroacetyl peptides could be activated by halide exchange using saturated KI solutions to yield the highly reactive No-iodoacetyl peptides. These findings were used to formulate a sequential thioether ligation strategy for the synthesis of EPF, a 101 amino acid protein containing three Gly-Gly sites approximately equidistantly spaced within the peptide chain. Four peptide segments or cassettes comprising the EPF protein sequence (BrAc-[EPF 78-101] 12, ClAc-[EPF 58-75]-[NHCH2CH2SH] 13, ClAc-[EPF 30-55]-[NHCH2CH2SH] 14, and Ac-[EPF 1-27]-[NHCH2CH2SH] 15) of EPF were synthesized in high yield and purity using Boc SPPS chemistry. In the stepwise sequential ligation strategy, reaction of peptides 12 and 13 was followed by conversion of the N-terminal chloroacetyl functional group to an iodoacetyl, thus activating the product peptide for further ligation with peptide 14. The process of ligation followed by iodoacetyl activation was repeated to yield an analogue of EPF (EPF psi(CH2S)(28-29,56-57,76-77)) 19 in 19% overall yield.

Binder treatment and lubricant system for aluminium P/M

Organic binders are used in premixes for powder metallurgy applications to prevent dusting and segregation. This is a particular problem for aluminium powder metallurgy because the dust is a potential safety hazard. The binder must also burn out completely at low temperatures in an inert environment and not react with the metal powders. It is demonstrated that cellulose acetate, polyvinyl acetate and polyvinyl alcohol are effective dedusting agents but they react with the metal powders during sintering and decrease the sintered density. Paraffin wan is an effect dedusting agent that provided die wall lubricity, does not interfere with sintering and increases tensile strength and ductility.

Texto para discuss??o 28: diagn??stico da situa????o da mulher na administra????o p??blica federal

O presente trabalho, desenvolvido pela Diretoria de Pesquisa e Difus??o da ENAP, tem como escopo apresentar um diagn??stico da condi????o das servidoras federais, comparando-o com a situa????o nas mesmas condi????es dos servidores masculinos. Nesse diagn??stico, apresentam-se dados sobre a inser????o do segmento feminino na administra????o p??blica federal: distribui????o por minist??rios em geral e por miss??o institucional, por natureza jur??dica (autarquias e funda????es), por faixa et??ria, por cargos e carreiras, por inscri????o e habilita????o em concursos p??blicos e por cargos comissionados (DAS). Na primeira parte, ser??o apresentados os dados levantados junto ?? Secretaria de Recursos Humanos do Minist??rio da Administra????o Federal e Reforma do Estado. Em paralelo, s??o elaboradas observa????es acerca dos aspectos mais relevantes no tocante a estas distribui????es

Lei n?? 8.140, de 28 de dezembro de 1990: altera a denomina????o da Funda????o Centro de Forma????o do Servidor P??blico - FUNCEP e d?? outras provid??ncias

A lei n?? 8.140, de 28 de dezembro de 1990 altera a denomina????o da Funda????o Centro de Forma????o do Servidor P??blico - FUNCEP e d?? outras provid??ncias.

Portaria n?? 649, de 28 de julho de 2014: requisitos para candidatar-se ao Banco Nacional de Avaliadores de Escolas de Governo

O documento disp??e sobre os requisitos para candidatar-se ao Banco Nacional de Avaliadores de Escolas de Governo.

Portaria n?? 180, de 28 de novembro de 2014: trata do Gestor de Seguran??a da Informa????o e Comunica????es (GeSIC), e do Comit?? de Seguran??a da Informa????o e Comunica????es (CSIC)

Nomear o Gestor de Seguran??a da Informa????o e Comunica????es (GeSIC) e os membros, titulares e suplentes, do Comit?? de Seguran??a da Informa????o e Comunica????es (CSIC)

Anotação, numa perspectiva de Direito Penal e de Criminologia, de alguns dos aspectos do Acórdão do Supremo Tribunal de Justiça (português), de 28 de Setembro de 2011 - os problemas do direito ao silêncio e do dever em o arguido se sujeitar a aplicações de prova no processo penal

Resumo: 1 – Sumário do Acórdão do Supremo Tribunal de Justiça, de 28 de Setembro de 2011; 2 – Texto completo do Acórdão do Supremo Tribunal de Justiça, de 28 de Setembro de 2011, Juiz Conselheiro Raul BORGES (Relator), Juiz Conselheiro Armindo MONTEIRO cfr. http://www.dgsi.pt , 20 de Janeiro de 2012; 3 – Anotação; 3.1 – Introdução à anotação; 3.2 – Algumas das referências, por parte do Acórdão do Supremo Tribunal de Justiça, de 28 de Setembro de 2011, aos problemas do direito ao silêncio e do dever em o arguido se sujeitar a aplicações de prova no processo penal; 3.3 – «Teoria geral» dos problemas do direito ao silêncio em contraste com o dever de sujeição do arguido a diligências de prova no contexto do direito processual penal lusitano; 4 - Conclusão. § Abstract: 1 - Summary of the Judgement of the Supreme Court of Justice of 28 September 2011 2 - Full text of the Judgement of the Supreme Court of Justice of 28 September 2011, Councillor Judge Raul Borges (Reporter), Councillor Judge Armindo Monteiro cf. . http://www.dgsi.pt, January 20, 2012, 3 - Note: 3.1 - Introduction to the annotation; 3.2 - Some of the references, by the Judgement of the Supreme Court of Justice of 28 September 2011, the problems the right to silence and the duty in the defendant be subject to applications of proof in criminal proceedings; 3.3 - "general Theory" of the problems the right to silence in contrast to the duty of subjection of the accused to proof steps in the right context criminal procedure Lusitanian 4 - Conclusion. P.S.: este é o "abstract" tal qual como surge no artigo.

RF Receiver Front End for 28.5 GHz Applications on a 70 GHz F-T SiGe BiCMOS Process

This article presents the design and test of a receiver front end aimed at LMDS applications at 28.5 GHz. It presents a system-level design after which the receiver was designed. The receiver comprises an LNA, quadrature mixer and quadrature local oscillator. Experimental results at 24 GHz center frequency show a conversion voltage gain of 15 dB and conversion noise figure of 14 5 dB. The receiver operates from a 2 5 V power supply with a total current consumption of 31 mA.