Análise de resistência à compressão do concreto para diferentes métodos de fabricação: Analysis of concrete compressive strength for different manufacturing methods

O concreto vem sendo um material muito comum e com grande aumento na sua usabilidade, fazendo com que as tecnologias, para melhoramento das suas características, estejam em pauta em muitos trabalhos acadêmicos, inclusive nas indústrias. No presente trabalho optou-se por analisar a compressão do concreto em diferentes tempos de cura, juntamente com os dois tipos de fabricação - manual e mecânico. Conclui-se que para se ter uma compressão que seja efetiva, ou seja, que faça o concreto ser mais resistente, é necessário seguir corretamente o passo a passo da fabricação do concreto e respeitar fatores que podem influenciar nessa resistência, tal como temperatura, tempo e tipo de cura e relação água/cimento, e método de produção, por exemplo

Obtaining of coating based onMn AND Co by dip-coating on ferritic stainless steel

Estudos vêm sendo desenvolvidos para melhorar a resistência à oxidação em temperaturas elevadas do aço inoxidável ferrítico, os quais têm sido propostos para fabricação de interconectores de células a combustível do tipo óxido sólido de temperatura intermediária (IT-SOFC). Dentre os revestimentos empregados, os revestimentos cerâmicos de óxidos do tipo espinélio têm sido os mais aplicados. Nesse contexto, no presente trabalho foram obtidos revestimentos à base de Mn e Co sobre aço inoxidável ferrítico (AISI430), utilizando a técnica de dip-coating. Os filmes obtidos foram caracterizados quanto à morfologia por MEV e quanto à composição elementar por EDS. Foi possível obter do revestimento à base de Mn e Co continuo e aderente sobre o substrato metálico.Studies have been developed to improve the oxidation resistance at elevated temperatures of ferritic stainless steel, which have been proposed for the fabrication of intermediate-temperature solid oxide fuel cell interconnectors (IT-SOFC). Among the coatings employed, ceramic coatings of spinel-type oxides have been the most applied. In this context, in the present work Mn and Co based coatings were obtained on ferritic stainlesssteel (AISI 430), using the dip-coating technique. The films obtained were characterized as to morphology by SEM and as to elemental composition by EDS. It was possible to obtain a continuous and adherent Mn and Co based coating over the metallic substrate

Spinel (NiFe)3O4 obtention by electrodeposition on ferritic stainless steel

Os aços inoxidáveis ferríticosapresentam características como, boa condutividade elétrica, boa resistência à corrosão e baixo custo, e uma das aplicações tem sido como interconectores em células a combustível de óxido sólido de temperatura intermediaria (ITSOFC), que operam a uma temperatura entre 600ºC a 800ºC. No entanto, a boa resistência à corrosão desta liga é atribuída à quantidade de Cr que em elevadas temperaturas forma uma película protetora de óxido de cromo (Cr2O3), prejudicando o desempenho dos interconectores. Nesse contexto, o presente trabalho tem por objetivo obter filmes de espinélios a base de Fe e Ni através da técnica de eletrodeposição. Os filmes de espinélios obtidos sobre o aço inoxidável foram caracterizados quanto à morfologia e microestrutura por MEV, EDS, DRX,e quanto à aderência. Os resultados obtidos mostraram que o filme é aderente ao substrato de aço inox AISI 430 e após tratamento térmico foi possível obter espinélios (NiFe)3O4.The ferritic stainless steels show properties as good electrical conductivity, good corrosion resistance and low cost, being that for this reason an application of this material has been in interconnectsfor Intermediate Temperature Solid Oxide Fuel Cells (ITSOFC) which work at temperatures between 600°C and 800°C. However, the stainless steel corrosion resistance is attributed to the amount of Cr, element that forms a chromium oxide (Cr2O3) layer, which acts as an oxidation protective, at high temperatures, but also reduces the interconnector performance due to its low conductivity. In this context, the objective of this work is to obtain Fe and Ni spinel coatings produced by electrodeposition. The spinel films deposited on stainless steel were characterized regarding their morphology and microstructure by SEM, EDS, XRD, oxidation resistance and adherence analysis. The results obtained showed that the films are adherent to the AISI stainless steel 430 substrate and pointed also thatthe used heat treatment procedure was effective in order to obtain crystalline spinels (NiFe)3O4

Hydrolysis time influence in obtaining hybrid film with addition of cerium ions for protecting galvanized steels

Las películas hibridas actúan como una barrera entre el substrato y el medio, reduciendo la velocidad de entrada del agua, electrolito, oxígeno y la penetración deiones agresivos hasta el metal, disminuyendo la velocidad de corrosión del substrato. Los principales factores que influyen en la resistencia a la corrosión de las películas híbridas son: el tiempo de curado, la concentración del baño, el pH de la solución de hidrólisis y el tiempo de hidrólisis. En este trabajo, se realizaron las pruebas con cuatro diferentes tiempos de hidrólisis (1, 3, 24 y 48 horas), el acero galvanizado fue revestido con una película híbrida obtenida a partir de un sol constituido por los precursores alcohoxidos 3-(trimetoxisililpropil) metacrilato (TMSPMA) y Tetraetoxisilano (TEOS) con adición de nitrato de cerio [0,01 M]. La caracterización de las películas fue realizada por MEB, perfilometria, ángulo de contacto, polarización y espectroscopia de impedancia electroquímica. Los resultados muestran que el tiempo de hidrólisis interfiere en la obtención de la película híbrida y consecuentemente en las propiedades protectoras de la película.The hybrid films act as a barrier layer between the substrate and the environment. This kind of coating reduces the electrolyte permeability, decreasing the corrosion rate of the substrate. However, many variables influenced the corrosion resistance of hybrid coating. The main factors that influence the thickness of the films are: temperature, curing time, the concentration alcooxide precursors on the bath, the pH of the hydrolysis and the hydrolysis time. In this study, the galvanized steel was coated with and hybrid film obtained from precursors consisting of a sol alcooxide 3-(trimetoxisililpropil) methacrylate (TMSPMA) and tetraethoxysilane (TEOS) with cerium nitrate addition [0,01 M]. The hydrolysis time was varied in four levels of (1, 3, 24 and 48 hours). The characterization of the films was performed by SEM, profilometry, contact angle determination, polarization and electrochemical impedance spectroscopy measurements. Results showed that the hydrolysis time presented influence on the hybrid film properties and consequently on the protection

Ti–Cp : eletrochemical behaviour under slurry erosion wear

The tests were performed using a new equipment, built to simulate aqueous erosion and monitor its electrochemical behaviour. This test was called electrochemical slurry erosion wear method. In this equipment, it is possible to measure the efect of simultaneous erosion wear and electrochemical tests on the passive flm behaviour. This kind of test on titanium was not found in the literature review, until now. The aim of this study was to analyse the behaviour of the passive titanium oxide layer, employing polarization curves simultaneously to the slurry erosion wear, unprecedented in the study of titanium passivity under erosive wear, varying the stirring speed and amount of erodent. Therefore, the hydrodynamic shear stress incurred under diferent stirring speed conditions exerts infuence on the corrosion resistance of commercially pure titanium (Ti–Cp)

Socio-environmental impacts of non-native and transplanted aquatic mollusc species in South America: What do we really know?

The impacts of biological invasions remain poorly known for some habitats, regions and taxa. To date, there has been no comprehensive effort to review and synthesize the impacts of invasive mollusc species in South America. In this paper, we provide a synoptic view on what is known on documented socio-ecological impacts of aquatic no-native mollusc species (NNMS) and transplanted mollusc species (TMS) from South America. An expert group involving malacologists and taxonomists from different countries, the “South America Alien Molluscs Specialists” (eMIAS), shared and summarized the scientific literature, databases, and published and unpublished information on confirmed impacts of NNMS and TMS in South America. Three broad categories, non-mutually exclusive were used as a framework: “Environmental/Biodiversity impacts”, “Economic and social effects”, and “Human health impacts”. Some 21 NNMS and seven TMS have documented impacts on at least one of those three categories. We encourage targeting the less known areas of research, such as economic valuation of human health (and veterinary) impacts attributable to NNMS or TMS and expand our knowledge of environmental impacts for the species listed in this study.Fil: Carranza, Alvar. Universidad de la República; Uruguay. Museo Nacional de Historia Natural Uruguay; UruguayFil: Agudo Padrón, Ignacio. Projeto “avulsos Malacológicos”; BrasilFil: Collado, Gonzalo A.. Universidad del Bio Bio; Chile. Sociedad Malacológica Chile; ChileFil: Damborenea, Maria Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fabres, Alejandra. Sociedad Malacológica Chile; Chile. Universidad Católica de Maule; ChileFil: Gutierrez Gregoric, Diego Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Lodeiros, Cesar. Universidad Técnica de Manabí; Ecuador. Universidad de Oriente; VenezuelaFil: Ludwig, Sandra. Universidade Federal de Minas Gerais; BrasilFil: Pastorino, Roberto Santiago Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Salvador, Rodrigo B.. Museum of New Zealand Te Papa Tongarewa,; Nueva Zelanda. The Artic University of Norway; NoruegaFil: Spotorno, Paula. Universidade Federal do Rio Grande; BrasilFil: Thiengo, Silvana. Fundación Oswaldo Cruz; BrasilFil: Vidigal, Teofania Heloisa Dutra Amorim. Universidade Federal de Minas Gerais; BrasilFil: Darrigran, Gustavo Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI