Fermented food products made with vegetable materials from tropical and warm countries: microbial and technological considerations

For many centuries, human beings have made fermented food, responding to the need to prolong the shelf life of perishable raw materials. Among the latter, vegetable materials come in diverse forms – roots, cereals, fruits, etc. – and vary from one location to another, especially if we study the products made in tropical and warm parts of the world. Humankind has explored many ways to ferment foods. This has led to the development of a number of different products characterised by original microbial communities, specific nutritional properties and typical sensory features. However, facing tremendous difficulties – sanitary preoccupations, nutritional needs and variability of organoleptic quality – scientists and food makers are now at a crossroads. One strategy would be to deduce which major traits should be optimised from a careful analysis of these products. The addition of selected starters may emerge from this as a good course of action. However, in this article, we consider that the use of traditional approaches – spontaneous fermentation and backslopping – is compatible with the search for higher quality in these products, on condition, though, that certain hygienic rules are respected and sufficient knowledge of microorganisms and raw materials is acquired.     

Structural resistance of chemically modified 1-D nanostructured titanates in inorganic acid environment

Sodium containing one-dimensional nanostructured layered titanates (1-D NSLT) were produced both from commercial anatase powder and Brazilian natural rutile mineral sands by alkali hydrothermal process. The 1-D NSLT were chemically modified with proton, cobalt or iron via ionic exchange and all products were additionally submitted to intensive inorganic acid aging (pH = 0.5) for 28 days. The morphology and crystal structure transformations of chemically modified 1-D NSLT were followed by transmission electron microscopy, powder X-ray diffraction, selected area electron diffraction and energy dispersive spectroscopy. It was found that the original sodium rich 1-D NSLT and cobalt substituted 1-D NSLT were completely converted to rutile nanoparticles, while the protonated form was transformed in a 70%–30% (by weight) anatase–rutile nanoparticles mixture, very similar to that of the well-known TiO₂-photocatalyst P25 (Degussa). The iron substituted 1-D NSLT presented better acid resistance as 13% of the original structure and morphology remained, the rest being converted in rutile. A significant amount of remaining 1-D NSLT was also observed after the acid treatment of the product obtained from rutile sand. The results showed that phase transformation of NSLT into titanium dioxide polymorph in inorganic acid conditions were controllable by varying the exchanged cations.Finally, the possibility to transform, through acid aging, 1-D NSLT obtained from Brazilian natural rutile sand into TiO₂-polymorphs was demonstrated for the first time to the best of authors' knowledge, opening path for producing TiO₂-nanoproducts with different morphologies through a simple process and from a low cost precursor.     

A Highly Efficient Olefin Metathesis Process for the Synthesis of Terminal Alkenes from Fatty Acid Esters

Recently, considerable attention has been focused on the use of olefin metathesis to convert oleochemicals into value-added products such as the bifunctional molecule methyl 9-decenoate, but the implementation of this process has been hampered by low ethenolysis efficiencies. We report herein the use of alpha olefins as ethylene surrogates in cross metathesis reactions with methyl oleate and soybean oil fatty acid methyl esters (soy FAME) resulting in considerable increases in catalyst efficiencies in the production of this promising chemical product. Additional gains in efficiency were realized by using a peroxide-scavenging feedstock pretreatment.     

Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

This study reports the influence of aluminium nitride on the pressureless sintering of cubic phase silicon carbide nanoparticles (β-SiC). Pressureless sintering was achieved at 2000 °C for 5 min with the additions of boron carbide together with carbon of 1 wt% and 6 wt%, respectively, and a content of aluminium nitride between 0 and 10 wt%. Sintered samples present relative densities higher than 92%. The sintered microstructure was found to be greatly modified by the introduction of aluminium nitride, which reflects the influence of nitrogen on the β-SiC to α-SiC transformation. The toughness of sintered sample was not modified by AlN incorporation and is relatively low (around 2.5 MPa m^1/2). Materials exhibited transgranular fracture mode, indicating a strong bonding between SiC grains.     

Leak Before Break procedure: Recent modification of RCC-MR A16 appendix and proposed improvements

This paper presents recent modifications of the Leak Before Break procedure of the A16 appendix from French RCC-MR nuclear code and the improvements that will be proposed. The first part of the study deals with the prediction of the crack size at penetration. In the case of small initial defect the validity of the Master Curve used in the A16 appendix is confirmed for pipes. For large initial defects, a correction to the A16 procedure is proposed to take into account the effect of large initial crack length on its size at penetration.     

Transformation invariance in pattern recognition: Tangent distance and propagation

In pattern recognition, statistical modeling, or regression, the amount of data is a critical factor affecting the performance. If the amount of data and computational resources are unlimited, even trivial algorithms will converge to the optimal solution. However, in the practical case, given limited data and other resources, satisfactory performance requires sophisticated methods to regularize the problem by introducing a priori knowledge. Invariance of the output with respect to certain transformations of the input is a typical example of such a priori knowledge. We introduce the concept of tangent vectors, which compactly represent the essence of these transformation invariances, and two classes of algorithms, tangent distance and tangent propagation, which make use of these invariances to improve performance. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 181–197, 2000     

Force polytope and force ellipsoid for redundant manipulators

Evaluation of force/motion capabilities for a manipulator is useful both in the design phase and in the operational phase. Manipulability ellipsoids and polytopes are well-known tools used to represent these capabilities graphically. This article focuses on the evaluation of force capabilities for redundant manipulators, for which additional constraints must be imposed on the available joint torques to satisfy the static assumption. An algorithm to correctly evaluate the task space force polytope is given and a new definition of the force ellipsoid is proposed. The obtained results can be applied also to nonredundant manipulators in singular configurations. Numerical results are provided in the case of a planar redundant arm. ©1997 John Wiley & Sons, Inc.     

PLA/MRPs乳液膜的制备及性能研究

以碱溶性半纤维素木聚糖和玉米醇溶蛋白合成的美拉德反应产物（MRPs）纳米颗粒水溶液为水相、聚乳酸/二氯甲烷溶液（PLA/DCM）为油相,通过乳液聚合法和模压成型工艺制备了PLA/MRPs乳液膜。分别利用傅里叶变换红外光谱仪、热重分析仪、扫描电子显微镜和紫外可见吸收光谱仪分析了PLA/MRPs复合材料的形貌结构和抗氧化性能,并对PLA/MRPs乳液膜的力学性能进行了探究。探讨了MRPs纳米颗粒水溶液的质量分数对PLA/MRPs乳液膜的抗氧化性能和力学性能的影响。结果表明,制得的PLA/MRPs复合材料具有水包油型结构,以质量分数0.50%MRPs制备的PLA/MRPs乳液膜在反应时间为30 h后,DPPH自由基清除率最大,为26.55%;而随着MRPs质量分数的增加,PLA/MRPs乳液膜的拉伸强度和断裂伸长率逐渐降低。     

氩等离子体紫外光A和B辐射属性计算

焊接等离子体释放的紫外光A （315~400 nm）和紫外光B （280~315 nm）是皮肤癌的重要诱因.基于净辐射系数的概念,考虑了连续谱（复合辐射和轫致辐射）和线谱等辐射机制,计算了氩等离子在常压、5 000~25 000 K内的紫外光A,B的辐射属性.结果表明,随着等离子体半径R_p增加,全谱辐射发生强烈的自吸收效应,而紫外光A,B基本无自吸收;当R_p=1 mm时,它们在总谱辐射（35~4 500 nm）的最大的占比分别为6.0%,1.9%,在非真空紫外辐射（200~4 500 nm）的最大的占比为36.3%和5%.为钨极氩弧的紫外光危害性研究提供了理论依据.     

A hierarchical modeling approach to the simulation and control of planar solid oxide fuel cells

The main aim of the paper is to propose hierarchical modeling as a suitable methodology to perform control-oriented analysis of planar solid oxide fuel cells (P-SOFC).