Analytical study for deformability of laminated sheet metal

While a freestanding high-strength sheet metal subject to tension will rupture at a small strain, it is anticipated that lamination with a ductile sheet metal will retard this instability to an extent that depends on the relative thickness, the relative stiffness, and the hardening exponent of the ductile sheet. This paper presents an analytical study for the deformability of such laminate within the context of necking instability. Laminates of high-strength sheet metal and ductile low-strength sheet metal are studied assuming: [1] sheets are fully bonded; and [2] metals obey the power law material model. The effect of hardening exponent, volume fraction and relative stiffness of the ductile component has been studied. In addition, stability of both uniform and nonuniform deformations has been investigated under plane strain condition. The results have shown the retardation of the high-strength layer instability by lamination with the ductile layer. This has been achieved through controlling the aforementioned key parameters of the ductile component, while the laminate exhibits marked enhancement in strength-ductility combination that is essential for metal forming applications

Controlling Bacillus cereus adherence to stainless steel with different cleaning and sanitizing procedures used in dairy plants / Controle do processo de adesão de Bacillus cereus ao aço inoxidável após diferentes procedimentos de limpeza e sanitização usados na indústria de laticínios

Bacillus cereus adherence to stainless steel used to milk contact surfaces was observed, depending on the cleaning and sanitizing procedures applied and the physicochemical properties of the surfaces. Numbers of surviving B. cereus after hygiene procedures were affected by temperature, the concentrations of both alkaline and acid washes, and the pH of the chlorine solution. The adhesion of B. cereus to the stainless steel was not thermodynamically favorable, and the adherence of this microorganism occurred in lower number, in accordance to the thermodynamic aspect of adhesion.

Foi observada a adesão de Bacillus cereus em superfície de aço inoxidável em contato com o leite, segundo o procedimento de limpeza, a sanitização e as propriedades físico-químicas da superfície. O número de B. cereus viáveis, após os procedimentos de higienização, foi afetado pela temperatura, pela concentração das soluções alcalinas e ácidas e pelo pH da solução clorada. A adesão de B. cereus em aço inoxidável não foi termodinamicamente favorável, e ocorreu pouca adesão desse microrganismo, de acordo com os aspectos termodinâmicos da adesão.

Biocompatibilidade do revestimento de nitreto de titânio (TiN): um estudo preliminar / Biocompatibility of nitride titanium revetment: a preliminary study

Com o objetivo de analisar o comportamento à biocorrosão do revestimento de TiN, no presente trabalho foram ensaiadas amostras de aço inoxidável austeníaco (AISI316L) e aço carbono comum (1015), com e sem revestimento. As análises foram feitas a partir de curvas potenciodinâmicas realizadas em meio fisiológico com adição de 10 por cento de soro bovino. As amostras revestidas apresentaram uma menor taxa de corrosão com relação às suas respectivas sem revestimento. O melhor desempenho foi encontrado nas amostras de aço 316L revestidas com TiN.

ABSTRACT - ln order to analise TiN coating biocorrosion performance, in the present work austenitic stainless steel (AIS! 3 l 6L) and carbon steel (SAE 1O15) sample with and without coating have been examined. If was seem smaller corrosion rates for coated samples compared to the uncoated samples. The best performance was find in the AIS! 3 l 6L stainless steel TiN coated samples. Potentiodynamic polarization tests using in fisiological medi um with 10% bovine serum adition were done