Improvement of the cavitation erosion resistance of UNS S31803 stainless steel by duplex treatment

A duplex surface treatment consisting of High Temperature Gas Nitriding (HTGN) followed by Low Temperature Plasma Nitriding (LTPN) was carried out in an UNS S31803 duplex stainless steel. The HTGN treatment was intended to produce a relatively thick and hard fully austenitic layer giving mechanical support to the thinner and much harder expanded austenite layer. HTGN was performed at 1200 degrees C for 3 h, in a 0.1 MPa N(2) atmosphere while LTPN, was carried out in a 75% N(2) + 25% H(2) atmosphere, at 400 degrees C for 12 h, under a 250 Pa pressure, and 450 V. An expanded austenite gamma(N) layer, 2.3 mu m thick, 1500 HVO.025 hard, was formed on top of a 100 mu m thick, 330 HV 0.1 hard, fully austenitic layer, containing 0.9 wt% N. For comparison purposes LTPN was carried out with UNS S30403 stainless steel specimens obtaining a 4.0 mu m thick, 1500 HV 0.025 hard, expanded austenite layer formed on top of a fully austenitic matrix having 190 HV 0.1. The nitrided specimens were tested in a 20 kHz vibratory cavitation-erosion testing equipment. Comparison between the duplex treated UNS S31803 steel and the low temperature plasma nitrided UNS S30403 steel, resulted in incubation times almost 9 times greater. The maximum cavitation wear rate of the LTPN UNS S30403 was 5.5 g/m(2)h, 180 times greater than the one measured for the duplex treated UNS S31803 steel. The greater cavitation wear resistance of the duplex treated UNS S31803 steel, compared to the LTPN treated UNS S30403 steel was explained by the greater mechanical support the fully austenitic, 330 HV 0.1 hard, 100 mu m layer gives to the expanded austenite layer formed on top of the specimen after LTPN. A strong crystallographic textured surface, inherited from the fully austenitic layer formed during HTGN, with the expanded austenite layer showing {101} crystallographic planes//surface contributed also to improve the cavitation resistance of the duplex treated steel. (C) 2010 Elsevier B.V. All rights reserved.

Assessment of the cavitation erosion resistance in high nitrogen austenitic stainless steels: study of the wear mechanisms

Specimens of a UNS S31803 steel were submitted to high temperature gas nitriding and then to vibratory pitting wear tests. Nitrided samples displayed fully austenitic microstructures and 0.9 wt. % nitrogen contents. Prior to pitting tests, sample texture was characterized by electron backscattering diffraction, EBSD. Later on, the samples were tested in a vibratory pit testing equipment using distilled water Pitting tests were periodically interrupted to evaluate mass loss and to characterize the surface wear by SEM observations. At earlier pit erosion, stages intense and highly heterogeneous plastic deformation inside individual grains was observed. Later on, after the incubation period, mass loss by debris detachment was observed. Initial debris micro fracturing was addressed to low cycle fatigue. Damage started at both sites, inside the grains and grain boundaries. The twin boundaries were the most prone to mass-loss incubation. Grains with (101) planes oriented near parallel to the sample surface displayed higher wear resistance than grains with other textures. This was attributed to lower resolved stresses for plastic deformation inside the grains with (101)

Mesoscale plasticity anisotropy at the earliest stages of cavitation-erosion damage of a high nitrogen austenitic stainless steel

A high nitrogen austenitic stainless steel (0.9wt% N) and an ordinary 304 austenitic stainless steel were submitted to cavitation-erosion tests in a vibratory apparatus operating at a frequency of 20 kHz. The high nitrogen stainless steel was obtained by high temperature gas nitriding a 1-mm thick strip of an UNS 31803 duplex stainless steel. The 304 austenitic stainless steel was used for comparison purposes. The specimens were characterized by scanning electron microscopy and Electron Back Scatter Diffraction. The surface of the cavitation damaged specimens was analyzed trying to find out the regions where cavitation damage occurred preferentially. The distribution of sites where cavitation inception occurred was extremely heterogeneous, concentrating basically at (i) slip lines inside some grains and (ii) Sigma-3 coincidence site lattice (CSL) boundaries (twin boundaries). Furthermore, it was observed that the CE damage spread faster inside those grains which were more susceptible to damage incubation. The damage heterogeneity was addressed to plasticity anisotropy. Grains in which the crystallographic orientation leads to high resolved shear stress show intense damage at slip lines. Grain boundaries between grains with large differences in resolved shear stress where also intensely damaged. The relationship between crystallite orientation distributions, plasticity anisotropy and CE damage mechanisms are discussed. (C) 2009 Elsevier B.V. All rights reserved.

Geochronology of weathering and landscape evolution, Dugald River valley, NW Queensland, Australia

40Ar/39Ar laser incremental heating analyses of individual grains of supergene jarosite, alunite, and cryptomelane from weathering profiles in the Dugald River area, Queensland, Australia, show a strong positive correlation between a sample’s age and its elevation. We analyzed 125 grains extracted from 35 hand specimens collected from weathering profiles at 11 sites located at 3 distinct elevations. The highest elevation profile hosts the oldest supergene minerals, whereas progressively younger samples occur at lower positions in the landscape. The highest elevation sampling sites (three sites), located on top of an elongated mesa (255 to 275 m elevation), yield ages in the 16 to 12 Ma range. Samples from an intermediate elevation site (225 to 230 m elevation) yield ages in the 6 to 4 Ma range. Samples collected at the lowest elevation sites (200 to 220 m elevation) yield ages in the 2.2 to 0.8 Ma interval. Grains of supergene alunite, jarosite, and cryptomelane analyzed from individual single hand specimens yield reproducible results, confirming the suitability of these minerals to 40Ar/39Ar geochronology. Multiple samples collected from the same site also yield reproducible results, indicating that the ages measured are true precipitation ages for the samples analyzed. Different sites, up to 3 km apart, sampled from weathering profiles at the same elevation again yield reproducible results. The consistency of results confirms that 40Ar/39Ar geochronology of supergene jarosite, alunite, and cryptomelane yields ages of formation of weathering profiles, providing a reliable numerical basis for differentiating and correlating these profiles. The age versus elevation relationship obtained suggest that the stepped landscapes in the Dugald River area record a progressive downward migration of a relatively flat weathering front. The steps in the landscape result from differential erosion of previously weathered bedrock displaying different susceptibility to weathering and contrasting resistance to erosion. Combined, the age versus elevation relationships measured yield a weathering rate of 3.8 m. Myr−1 (for the past 15 Ma) if a descending subhorizontal weathering front is assumed. The results also permit the calculation of the erosion rate of the more easily weathered and eroded lithologies, assuming an initially flat landscape as proposed in models of episodic landscape development. The average erosion rate for the past 15 Ma is 3.3 m. Myr−1, consistent with erosion rates obtained by cosmogenic isotope studies in the region.

The Alzheimer`s Association external quality control program for cerebrospinal fluid biomarkers

Background: The cerebrospinal fluid (CSF) biomarkers amyloid beta (A beta)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer`s disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer`s Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program. Methods: The program is open for laboratories using commercially available kits for A beta, T-tau, or P-tau. CSF samples (aliquots of pooled CSF) are sent for analysis several times a year from the Clinical Neurochemistry Laboratory at the Molndal campus of the University of Gothenburg, Sweden. Each round consists of three quality control samples. Results: Forty laboratories participated. Twenty-six used INNOTEST enzyme-linked immunosorbent assay kits, 14 used Luminex xMAP with the INNO-BIA AlzBio3 kit (both measure A beta-(1-42), P-tau(181P), and T-tau), and 5 used Mesa Scale Discovery with the A beta triplex (A beta N-42, A beta N-40, and A beta N-38) or T-tau kits. The total coefficients of variation between the laboratories were 13% to 36%. Five laboratories analyzed the samples six times on different occasions. Within-laboratory precisions differed considerably between biomarkers within individual laboratories. Conclusions: Measurements of CSF AD biomarkers show large between-laboratory variability, likely caused by factors related to analytical procedures and the analytical kits. Standardization of laboratory procedures and efforts by kit vendors to increase kit performance might lower variability, and will likely increase the usefulness of CSF AD biomarkers. (C) 2011 The Alzheimer`s Association. All rights reserved.

Ethnicity and Arterial Stiffness in Brazil

BACKGROUND The impact of increased central arterial stiffness as a predictor of morbidity and mortality, independently of other cardiovascular (CV) risk factors, has been established. The main aim of the present work was to investigate the association of ethnicity on arterial stiffness in different ethnic groups from the Brazilian population. METHODS A total of 1,427 individuals from the general population were randomly selected from the Vitoria City metropolitan area and 588 Amerindians from a native community in Brazil. The ethnicity of the general population was classified by a standard questionnaire as Caucasian descent, African descent, or Mulattos (considered racially mixed subjects). Pulse wave velocity (PWV) was measured with a noninvasive automatic device (Complior, Colson; Garges les Gonesses, France). RESULTS Hemodynamic data of PWV, systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) was higher in African descent individuals than in the other groups (P < 0.001). These results were still observed after adjustment for age and mean arterial pressure (P < 0.001). In addition, studying only normotensive individuals, PWV adjusted levels were higher in African descent individuals, and lower in Amerindians when compared with other ethnic groups (P < 0.01), showing, without the possible confounder effects of time and severity of hypertension or medication use, that PWV is associated with ethnicity in our population. CONCLUSION The study of different ethnic groups from a highly admixtured population was able to demonstrate an association between ethnicity and arterial stiffness.

Compromisso nacional para aperfei??oar as condi????es de trabalho na cana-de-a????car

O Compromisso Nacional para Aperfei??oar as Condi????es de Trabalho na Cana-de-A????car, firmado pelo Governo Federal e entidades de trabalhadores e empres??rios do setor sucroenerg??tico, ?? resultado de uma experi??ncia in??dita no pa??s de negocia????o tripartite para enfrentar o desafio de melhorar as condi????es de vida e trabalho no cultivo manual da cana-de-a????car. Por meio de uma Mesa de Di??logo, sob a coordena????o da Secretaria-Geral da Presid??ncia da Rep??blica, foi constru??do um acordo hist??rico para valorizar e disseminar as melhores pr??ticas trabalhistas na lavoura da cana, evidenciando a import??ncia do di??logo social na elabora????o das Pol??ticas P??blicas. Atrav??s da ades??o volunt??ria das empresas ao Compromisso, da divulga????o das boas pr??ticas empresariais e do cadastro positivo formado pelo selo ???Empresa Compromissada???, conferido ap??s verifica????o in loco de auditoria independente, a iniciativa induz os demais atores do setor a aderir ao Compromisso e adotar as boas pr??ticas trabalhistas

Uma base para o desenvolvimento de estrat??gias de aprendizagem para a gest??o de riscos no servi??o p??blico

Este Caderno traz o relat??rio elaborado pela Mesa-Redonda de Pesquisa A????o sobre Gest??o de Riscos, do Centro Canadense para o Desenvolvimento da Gest??odo Canad??, que objetiva principalmente avaliar as v??rias iniciativas e estudos realizados, identificar princ??pios b??sicos e pr??ticas positivas e definir mecanismos para estimular a divulga????o de estudos te??ricos e medidas pr??ticas no campo da gest??o de riscos

Do her??ico ao cotidiano: li????es aprendidas na condu????o de projetos horizontais

Este Caderno traz o relat??rio elaborado pela Mesa-Redonda de Pesquisa A????o sobre a Gest??o de Iniciativas Horizontais, do Centro Canadense para o Desenvolvimentoda Gest??o do Canad??, que objetiva avaliar iniciativas e pesquisas realizadas,identificar li????es e oferecer orienta????es pr??ticas a gerentes sobre efic??ciaem gest??o horizontal

Aprendizagem ao alcance de todos: a experi??ncia do governo canadense em educa????o por meio eletr??nico

Este trabalho publicado originalmente pelo Canad?? School of Public Service (CSPS), e elaborado a partir dos estudos e da experi??ncia em aprendizagem por meio eletr??nico (e-learning) do setor p??blico canadense, tem por objetivo disseminar a utiliza????o dessa modalidade de ensino a educadores e t??cnicos que trabalhem diretamente com Educa????o a Dist??ncia (EAD) no setor p??blico. Ao procurar esclarecer o processo de aprendizagem, do ponto de vista dos conceitos, das t??cnicas e da operacionaliza????o, o trabalho lan??a luz sobre as vantagens e o potencial que essa modalidade de ensino apresenta para as organiza????es p??blicas, apontando inclusive as armadilhas e obst??culos que devem ser observados em seu uso

Conv??nio do sistema de gest??o participativa

O Sistema de Gest??o Participativa (SGP) adotado pela CAF/SP trata-se de um sistema de regula????o das rela????es administra????o-sindicato, destinado a promover o envolvimento, a participa????o e a integra????o dos fiscais nos assuntos de interesse da institui????o e da corpora????o. Com a iniciativa foi formulado e aplicado um sistema de ???Avalia????o Integrada das GRAFs???, abrangendo chefias, servidores administrativos, FCPs em trabalho de rua e FCPs em trabalho interno. A Mesa de Participa????o Permanente apreciou 14 quest??es, alcan??ando solu????es consensuais em 11 delas e aprovou o princ??pio geral pelo qual os fiscais e o Sindicato devem ter acesso e participa????o mais efetiva no planejamento da a????o fiscal, sendo essa participa????o considerada fundamental para uma nova abordagem da produtividade fiscal. Foi constitu??do o Grupo de Estudo da Previd??ncia, por representantes do SINDIFISP/SP, APAFISP e CAF, todos eles fiscais de alta qualifica????o profissional e intelectual que produziram estudos, an??lises cr??ticas e propostas sobre o sistema previdenci??rio brasileiro reunidas em livro editado pelo SINDIFISP. A partir de levantamento junto aos FCPs e aos gerentes das GRAFs foram levantadas sugest??es para melhoria da qualidade do ???Plant??o Fiscal de Atendimento ao Contribuinte???, que foram implantadas e transformadas em normas administrativas. Foi tomada a decis??o de realizar-se ???Avalia????o Semestral??? junto aos usu??rios quanto ao atendimento prestado em cada GRAF. Decidiu-se, ainda, pela elabora????o do ???Manual do Plantonista???, destinado a padronizar procedimentos e orientar condutas, que ficar?? ?? disposi????o tamb??m dos usu??rios. Observam-se melhorias de qualidade das rela????es profissionais e aumento dos n??veis de arrecada????o previdenci??ria

Racionaliza????o do almoxarifado

Ap??s a implanta????o da Gest??o pela Qualidade Total, o 4?? Regimento de Carros de Combate (RCC) do Comando Militar do Sul constatou a necessidade de eliminar o desperd??cio de material de faxina e de expediente, e a perda de tempo e excesso de burocracia em seu almoxarifado. Como solu????es, foram adotadas as seguintes provid??ncias: montagem de um box (contendo uma estante de metal, uma mesa, um estrado, um quadro de avisos e uma prancheta) para cada subunidade guardar o seu material no almoxarifado; montagem de uma se????o de fardamento para aproveitamento de espa??o no almoxarifado e delimita????o das ??reas de tr??nsito; aquisi????o de software para montagem de licita????es. Os resultados foram: o consumo de material de expediente e de faxina na exata dimens??o das necessidades de cada reparti????o ou subunidade do Regimento, obtendo economias superiores ??s estabelecidas como meta, em virtude do consumo dos estoques excedentes aprovisionados, aumento do controle do material pelos usu??rios e elimina????o dos comportamentos de desperd??cio, pedidos em excesso, etc, agiliza????o das atividades no almoxarifado, com elimina????o total de filas e redu????o a zero do tempo de espera para recebimento e envolvimento dos integrantes do Regimento no processo de redu????o de custos da unidade, gerenciando sua rotina e sendo avaliados pelos resultados obtidos

Relat??rio de atividades 2004

A capacita????o de servidores p??blicos ?? uma ferramenta fundamental para que as pol??ticas de governo sejam implementadas de forma efetiva e sustent??vel. Neste sentido, os produtos desenvolvidos pela Escola Nacional de Administra????o P??blica - ENAP como oficinas, cursos presenciais e a dist??ncia, estudos, interc??mbios, parcerias nacionais e internacionais, t??m por objetivo produzir impacto direto na qualidade das a????es final??sticas dos ??rg??os. Procura-se realizar a capacita????o dos servidores p??blicos de forma integradora, tendo em conta a especificidade de cada tema e, ao mesmo tempo, abordando os fundamentos que devem embasar toda a????o p??blica, os quais se situam no campo da ??tica, da democracia e da justi??a social.

Inovasus: um incentivo ??s novas pr??ticas

O Pr??mio Inovasus consiste em uma iniciativa in??dita no Minist??rio da Sa??de, coordenada pelo Departamento de Gest??o e da Regula????o do Trabalho em Sa??de (Degerts), da Secretaria de Gest??o do Trabalho e da Educa????o na Sa??de (SGTES), que tem como objetivo identificar, reconhecer e valorizar pr??ticas inovadoras da gest??o do trabalho na sa??de, considerando a necessidade de estrutura????o e fortalecimento no ??mbito dos Estados, Distrito Federal, regi??es e Munic??pios, a partir dos protocolos homologados no ??mbito da Mesa Nacional de Negocia????o Permanente do SUS (MNNP-SUS), que se constituem refer??ncias para a melhoria das condi????es de trabalho nos entes federativos. Esta iniciativa proporciona o reconhecimento e d?? visibilidade ??s experi??ncias locais, fortalecendo o campo da gest??o do trabalho

Caf?? com debate: em busca de uma nova s??ntese para a administra????o p??blica

A Escola Nacional de Administra????o P??blica (ENAP) realizou o ??ltimo encontro do ciclo de Caf??s com Debate sobre a pesquisa ???Em busca de uma Nova S??ntese para a Administra????o P??blica???. Participaram do debate R??mulo Paes (secret??rio executivo do Minist??rio do Desenvolvimento Social e Combate ?? Fome - MDS) e Laura Parente (douturanda e pesquisadora da Universit?? Paris-Est Marne-laVall??e). O tema discutido foram as contribui????es da Nova S??ntese e implica????es para a reforma e a renova????o do setor p??blico, tema da mesa-redonda realizada em Londres