Emulsifier and antioxidant properties of by‐products obtained by enzymatic degumming of soybean oil

The enzymes used in degumming, called phospholipases, specifically act on phospholipids without degrading the oil itself. Degumming using a phospholipase C enzyme allows to meet all market specifications while it increases the oil yield. The aim of this study was to evaluate antioxidant and emulsifier properties of the recovered gum (RG) obtained by enzymatic oil degumming process of crude soybean oil subjected to modifications as deoiling (RG deoiled) or ethanol fractionation (RG soluble and insoluble). RG soluble allowed obtaining more stable oil‐in‐water emulsions (30:70 w/w) in comparison with those by‐products assayed at different concentrations (0.1–1.0%). Also, deoiled soybean lecithin (DSL) and RG deoiled had a similar behavior in relation to the kinetic destabilization (% backscattering profiles), despite the different degumming processes used to obtain these samples. The study on induction times (Metrohm Rancimat) showed a significant antioxidant effect (p<0.05) against a refined sunflower oil associated with all the by‐products analyzed. However, RG soluble and DSL showed a strong effect on the oil stability at high concentrations (1000–2000 ppm). These results showed that the deoiled recovered gum and its derivates obtained by ethanol fractionation are a potential alternative for industrial application as additive. Practical applications: The economic benefits of enzymatic degumming process have also been quantified by several oilseed processors. This process allows obtaining a by‐product with a high concentration of different phospholipids. This study intends to increase the commercial value of this recovered gum contributing to the food industry with useful information about their functional properties.     

AZ31镁合金活性TIG焊接头分析

针对AZ31镁合金材料,研究了在A—TIG焊中单一成分的活性剂对焊缝成形的影响。试验结果表明,与无活性剂的焊缝相比,活性剂TiO2、SiO2、Cr2O3、CdCl2和CaCl2能够有效地增加镁合金焊缝的熔深和深宽比。镁合金涂敷活性剂CdCl2后焊缝接头的微观组织与未涂敷时焊缝接头的微观组织没有明显区别,只是前者热影响区稍宽。未涂敷活性剂和涂敷CdCl2的试样硬度值分布相差不大。在AZ31镁合金的焊接中,活性剂CdCl2的作用效果最好。     

Forging of Mg‐Alloys AZ31 and AZ80

Mg‐wrought alloys recently became an engineer material of constantly increasing interest. The mechanical properties of extruded Mg‐feedstock of the alloys AZ80 and AZ31 indicate their suitability for automotive applications in form of high‐quality forgings. Therefore a detailed knowledge about the forming behaviour is of particular importance. In order to compare mechanical properties of available Mg‐feedstock qualities compression tests at room temperature have been carried out by applying batches of AZ31‐ and AZ80‐feedstock. Cylindrical specimens were made out of received continuously casted as well as extruded AZ31‐ and AZ80 ‐ rods. A quantitative analysis of Mg‐feedstock’s microstructure has been carried out. The characterization of the deformability of applied Mg‐feedstock under hot working conditions could be performed by means of uniaxial plain strain upsetting tests at temperatures between 300 and 450 °C as well as logarithmic strain rates of 10^‐1, 1 and 10s^‐1. It is shown that the chosen parameter range ensures an enhanced deformability of continuously as well as extruded Mg‐feedstock. The subsequently carried out determination of microstructural evolution could be related to obtained flow stress curves of applied batches of Mg‐feedstock. Furthermore, FVM/FEM‐systems have been employed in order to design a simplified geometry of heated forging dies suitable for forging tests. The tests have been carried out by means of a hydraulic press. During the tests their punch velocity has been varied between 1 and 40 mm/s. Hence numerically simulated results could be confirmed by practical tests. Exemplary forgings of a simplified shape were made out of all applied batches of Mg‐feedstock. No remarkable failures have been detected.     

基于塘子凹31-1#矿体的采场地压及位移监测研究

运用MKⅡ型收敛仪和MC型钻孔应力计对云锡塘子凹31－1^#矿体进行现场收敛及应力量测，得出了一些有价值的结论。这些结论为该矿体的采矿优化提供了理论支持，同时为其它矿山提供技术借鉴，也验证了现场量测量在矿山开采中的重要性。     

塘子凹坑31-1#矿体的采矿设计优化

利用三维有限元对塘子凹坑31－1^#矿体进行了采矿设计优化，模拟得出的结论经过了首采矿块的实际验证，模拟结果与实际基本吻合，证明三维有限元在地下矿山的开采优化设计中是能够得到推广应用的。     

In vivo MR investigation of skeletal muscle function in small animals

In vivo ³¹P-MRS investigations have been widely used in small animals to study skeletal muscle function under normal and pathological conditions. Paradoxically in these studies, the benefit provided by ³¹P-MRS in terms of non-invasiveness is lost because of the utilization of experimental setups that integrate invasive devices for inducing muscle contractions and for measuring mechanical performance. These traditional methodologies, which require surgical preparations, have obvious limitations regarding repeatability in the same animal. The purpose of this review is to highlight the technical aspects of the in vivo MR investigations of skeletal muscle function in small animal models. We will more particularly address the issue related to the invasiveness of different procedures used so far in order to show finally that a further step into non-invasiveness can be achieved, in particular with the support of muscle functional ¹H-MRI.     

Limit Values of Derivatives of the Cauchy Integrals and Computation of the Logarithmic Potentials

We derive limit values of high-order derivatives of the Cauchy integrals, which are extensions of the Plemelj-Sokhotskyi formula. We then use them to develop the Taylor expansion of the logarithmic potentials at the normal direction. Based on the Taylor expansion and numerical integration methods for weekly singular functions using grid points, we design fast algorithms for computing the logarithmic potentials. We prove that these methods have an optimal order of convergence with a linear computational complexity. Numerical examples are included to confirm the theoretical estimates for the methods.     

Preliminary study of biodegradation of AZ31B magnesium alloy

Magnesium alloys are potential to be developed as a new type of biodegradable implant material by use of their active corrosion behavior. Both in vitro and in vivo biodegradation properties of an AZ31B magnesium alloy were investigated in this work. The results showed that AZ31B alloy has a proper degradation rate and much lower hydrogen release in Hank’s solution, with a degradation rate of about 0.3 mm/year and hydrogen release below 0.15 mL/cm². The animal implantation test showed that the AZ31B alloy could slowly biodegrade in femur of the rabbit and form calcium phosphate around the alloy sample, with the Ca/P ratio close to the natural bone.