Design and shape optimization of a new type of hollow concrete masonry block using the finite element method

This study describes the development of a new type of hollow concrete masonry block unit in order to minimize its weight based on topological optimization and design of experiments (DOE). This key factor is the most important parameter in human and robotic block handling in masonry construction, due to the traditionally heavy weight of the blocks. With this aim, it was necessary to use the finite element method (FEM) to calculate the compressive resistance of the different concrete block designs and then to choose the optimum hollow block from the handling and structural points of view. The nonlinearity in this problem is due to the material behaviour of the concrete. In this way a combined mathematical model (Drucker-Praguer and Willam-Warnke material models) for concrete was implemented and solved using the FEM. The numerical results of the candidate blocks give rise to new solutions in masonry construction through the adequate redesign of the blocks. These new block designs are lighter, keeping the structural resistance and improving the block handling. Finally, conclusions of the study are given.     

Nonenzymatic Browning and Chemical Changes During Grape Juice Storage

The effect of storage on juice concentrate from 2 red grape (Merlot and Criolla) and 1 white grape (Yellow Muscat) varieties on color and chemical composition, at temperatures ranging from 10 to 30 °C, was investigated. Color deterioration as A420 occurred at a faster rate in juice made with Merlot variety. The same was true when the pigment destruction as A520/420 was studied. Total reducing sugar, fructose‐to‐glucose ratio, and proline (the only significant amino acid present in grape juice) remained practically constant during storage. The hydroxymethyl‐furfural (HMF) buildup reaction proceeded faster in Criolla grape juice. Independent of variety, a detectable amount of HMF was produced only after 12 wk of storage at any temperature.     

Contribution of Evolutionary Selected Immune Gene Polymorphism to Immune-Related Disorders: The Case of Lymphocyte Scavenger Receptors CD5 and CD6

Pathogens are one of the main selective pressures that ancestral humans had to adapt to. Components of the immune response system have been preferential targets of natural selection in response to such pathogen-driven pressure. In turn, there is compelling evidence showing that positively selected immune gene variants conferring increased resistance to past or present infectious agents are today associated with increased risk for autoimmune or inflammatory disorders but decreased risk of cancer, the other side of the same coin. CD5 and CD6 are lymphocytic scavenger receptors at the interphase of the innate and adaptive immune responses since they are involved in both: (i) microbial-associated pattern recognition; and (ii) modulation of intracellular signals mediated by the clonotypic antigen-specific receptor present in T and B cells (TCR and BCR, respectively). Here, we review available information on CD5 and CD6 as targets of natural selection as well as on the role of CD5 and CD6 variation in autoimmunity and cancer.     

Synthesis of ScAlN thin films on Si (100) substrates at room temperature

Microsystem Technologies - Scandium aluminum nitride alloy (ScAlN) thin films have been synthesized using reactive sputtering of a scandium aluminum alloy (Sc0.40Al0.60) target on Si (100)...     

A new way to conduct enzymatic synthesis in an active membrane using ionic liquids as catalyst support

Several active membranes were prepared by immobilization of Candida antarctica lipase B (CALB) onto the surface of ceramic membranes via three different ionic liquids (ILs): [bmim⁺][PF₆⁻], [emim⁺][NTf₂⁻] and [bmim⁺][NTf₂⁻] and compared to an active membrane obtained by simple enzyme adsorption. The performances of these various membranes were evaluated by studying the synthesis of butyl laurate by the acidolysis between butyl acetate and lauric acid in a hexane/water mixture (98:2, v/v). The results obtained show that all the membranes prepared with or without ILs were active and maintained their activity after several runs and during some months.     

Processing and characterization of porous Ti2AlC with controlled porosity and pore size

In this work, we demonstrate a simple and inexpensive way to fabricate porous Ti₂AlC, one of the best studied materials from the MAX phase family, with controlled porosity and pore size. This was achieved by using NaCl as the pore former, which was dissolved after cold pressing but before pressureless sintering at 1400 °C. Porous Ti₂AlC with samples a volume fraction of porosity ranging from ～10 to ～71 vol.% and different pore size ranges, i.e. 42–83, 77–276 and 167–545 μm, were successfully fabricated. Fabricated samples were systematically characterized to determine their phase composition, morphology and porosity. Room temperature elastic moduli, compressive strength and thermal conductivity were determined as a function of porosity and/or pore size. For comparison, several samples pressureless-sintered without NaCl pore former, or fabricated by spark plasma sintering, were also characterized. The effects of porosity and/or pore size on the room temperature elastic moduli, compressive strength and thermal conductivity of porous Ti₂AlC are reported and discussed in this work. It follows that porosity can be a useful microstructural parameter to tune mechanical and thermal properties of Ti₂AlC.     

Structural and compositional homogeneity of InAlN epitaxial layers nearly lattice-matched to GaN

A group of InAlN films was fabricated by molecular beam epitaxy and investigated by X-ray diffraction, transmission electron microscopy and element nano-analyses. All top In_xAl_1?xN layers have compositions around lateral lattice-matching to GaN (x ≈ 0.18) and are pseudomorphic. For a growth rate of 350 nm h^?1, each InAlN film separated into two sublayers with different In/Al-ratios. Micrographs reveal sharp transitions both at the InAlN/GaN and at the InAlN/InAlN interfaces. In contrast to these separated layers, an optimized epitaxy using an AlN interlayer and a lower growth rate, 100 nm h^?1, enabled the fabrication of a single-phase In_xAl_1?xN layer on GaN, homogeneous on a nanoscopic scale.     

Measurement of Peroxidic Species in Ozonized Sunflower Oil

Peroxidic species in ozonized sunflower oil using different methods as iodometric and ferrous oxidation in xylenol orange (FOX) were measured. The necessary reaction time from two minutes up to 36 hours using iodometric assay in ozonized sunflower oil was determined. Peroxide values achieved maximum values at 24 hours of reaction time. Hydroperoxides content measured by FOX assay and peroxide value determined at two minutes using iodometric assay had a linear relationship (r² = 98.18%), while, at 24 hours a logarithmic relationship (r² = 98.39%) was shown. Values of hydroperoxides were lower than peroxides values at 24 hours and represent between 23 and 44% in all samples of ozonized sunflower oil studied.