Vapor Pressure of Allyl Isothiocyanate and Its Transport in PVDC/PVC Copolymer Packaging Film

Equilibrium vapor pressures of allyl isothiocyanate (AIT) above pure AIT and AIT/canola oil mixtures from 15 to 45°C were estimated from AIT vapor densities using gas chromatography. Canola oil was an effective diluent for depressing AIT vapor pressure. Permeation of AIT in a PVDC/PVC copolymer film was measured using the dynamic quasi-isostatic method, and kinetics of AIT vapor sorption in the polymer were studied gravimetrically. Experiments were carried out at 25, 35 and 45°C with vapor pressures from 50 to 800 Pa. At fixed vapor activity, diffusion and permeability coefficients increased with temperature, but a decrease was observed for solubility coefficient. An empirical equation was used to describe the sorption kinetics.     

万朵红花怒放四川

花是爱的礼物,也是纪念、抒发对死者悲伤的情感. 2008年5月12日北京时间14:28时,四川汶川发生8.0级大地震,造成至少500万人无家可归.     

Effect of aluminizing treatment on the oxidation properties of 12Cr heat resisting steel

In order to investigate the effect of aluminization on the oxidation properties of 12Cr martensitic heat resisting steel, a specimen was prepared by forging after centrifugal casting. After aluminizing treatment under various conditions, scanning electron microscopy observation, and hardness, line profile and x-ray diffraction analysis of the alloy layer were performed. The results confirmed that the thickness of the layer of Al₁₃Fe₄, with a Vickers hardness of over 880, increased with increasing aluminizing temperature and time. Moreover, it was concluded from the results of the oxidation experiment that the oxidation properties of the aluminized specimen were improved by up to approximately 30 %.     

生物医用植入体钛基合金及其表面生物活性氧化层的制备:机遇与挑战

钛及其合金因其优异的力学性能和良好的生物相容性,长期以来一直被用作植入材料.尽管如此,研究人员和行业仍在积极寻求更好的合金,因为仍有一些迫切的问题需要关注,包括:(1)由于种植体材料与人体骨组织的弹性模量不匹配而导致的应力屏蔽问题;(2)Ti合金长期使用后有害离子的释放问题;(3)钛合金表面生物活性低而导致愈合过程延长...     

Effect of <i>Lycopus lucidus</i> Turcz. supplementation on gut microflora and short chain fatty acid composition in Crj: CD-1 mice

We investigated the diversity and composition of microflora in feces of Lycopus lucidus Turcz.-fed mice. In addition, we evaluated the production of major cytokines (Interleukin-6 and -10) which are related to inflammation and fatty acid composition of several tissues. 16S ribosomal DNA sequencing-based microbiome taxonomic profiling analysis was performed utilizing the EzBioCloud data base. Male mice fed on L. lucidus showed a significantly reduced number of lactic acid bacteria and coliform in the feces compared with the control group (p < 0.05). 16S rDNA sequencing analysis of fecal samples showed that L. lucidus supplementation decreased the community of harmful microflora (Enterobacteriaceae including Escherichia coli and Bacteroides sp.) in feces compared with the control group (p < 0.05). There were no significant differences in mRNA expression of cytokine IL-6 and IL-10 between the control and L. lucidus fed groups. The fecal fatty acid composition in the L. lucidus group had percentages of 4:0, 6:0, 8:0 and 10:0 in the intestine but those short chain fatty acids were not detected in the control group. Our results showed that L. lucidus supplementation influenced gut environment by decreasing harmful microflora and increased the percentages of several short fatty acids.     

Numerical analysis and experimental validation of surface roughness and morphology in honing of Inconel 718 nickel-based superalloy

Honing is an important technology for machining onboard system parts. The parts are usually made of difficult-to-machining materials, e.g., Inconel 718 superalloy. Honing can improve the finishing accuracy and surface quality. However, the selection of the honing parameters was primarily based on the results of a large number of experiments. Therefore, the establishment of a reliable model is needed to predict the honed surface roughness and morphology, and offers a theoretical direction for the choice of parameters. In the present study, a numerical simulation model was constructed for analysis of the honing process by Python. The oilstone, workpiece surface morphology and motion trajectory were discretized by Python, and the machined surface was obtained by trajectory interference. Firstly, based on the statistical analysis of the surface topography of oilstone, the shape of grains was simplified and the surface topography of oilstone was built accordingly. Then, the initial surface morphology of the workpiece was constructed and the trajectory of grains on the workpiece surface was analyzed, which showed the distribution of the removed material. Meanwhile, the plastic deformation of material was analyzed in the simulation model. The critical depth of three stages of contact between grains and workpiece was calculated by the theoretical formula: scratching, ploughing and cutting. By analyzing the distribution of bulge, the plastic deformation in ploughing and cutting stage was studied. Further, the simulated results of honed surface roughness and morphology were validated and agreed reasonably well with the honing experiment. Finally, the effects of honing process parameters, including grain size, tangential speed, axial speed, radial speed and abrasive volume percentage, on the surface roughness of the workpiece were analyzed by the simulation model. The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00422-0     

Rapid Repair of Earthquake Damaged RC Interior Beam-wide Column Joints and Beam-wall Joints Using FRP Composites

This paper studies the seismic performance of FRP-strengthened RC interior non-seismically detailed beam-wide columns and beam-wall joints after limited seismic damage.Four eccentric and concentric beam-wide column joints and two beam-wall joints,initially damaged in a previous study,were repaired and tested under constant axial loads(0.1fc′Ag and 0.35fc′Ag) and lateral cyclic loading.The rapid repair technique developed,aimed to restore the original strength and to provide minimum drift capacity.The repair...     

A Comparison between Direct and Indirect Laser Sintering of Metals

Layer manufacture technologies are gaining increasing attention in the manufacturing for the production of polymer mould tooling. Layer manufacture techniques can be used in this potential manufacturing area to produce tooling either indirectly or directly, and powder metal based layer manufacture systems are considered as an effective way of producing rapid tooling. Mechanical properties and accuracy are critical for tooling. This paper reports the results of an experimental study examining the potential of layer manufacturing processes to deliver production tooling for polymer manufacture. A comparison between indirectly selective laser sintering and directly selective laser sintering to provide the tooling was reported. Three main areas were addressed during the study： mechanical strength, accuracy, and build rate. Overviews of the results from the studies were presented.     

High temperature mechanical properities and creep crack initiation of DS CM186LC for nozzle guide vane

The second generation DS alloy, CM186LC is used in the as-cast and double aged condition which has creep-rupture properities equivalent to the first generation single crystal alloys CMSX-2 and CMSX-3. In production, cast vane components have to be subjected to a brazing treatment for joining into pairs. The effect of the brazing treatment and modified brazing treatment (heat treatment) on mechanical properities at high temperature was studied in accordance with microstructure. Brazing treatments gave no effect on tensile properities and creep failure mode of DS CM186LC, although a small decrease in stress-rupture life was observed. Creep failure was related to the solidified microstructure. Creep cracks began at the grain boundary normal to the applied stress, especially at the γ/γ’ eutectic phase on grain boundaries. Most of γ/γ’ eutectics which had solidified at the last stage of casting, had microporosity which became a crack initiation site during creep. MC carbide reaction with the matrix γ was observed in the creep failed specimens.