Ultimate strength of perforated steel plates under edge shear loading

The aim of the present study is to investigate the ultimate strength characteristics of perforated steel plates under edge shear loading, which is a primary action type arising from cargo weight and water pressure in ships and ship-shaped offshore structures. The plates are considered to be simply supported along all (four) edges and kept straight. The cutout is circular and located at the center of the plate. A series of ANSYS nonlinear finite element analyses (FEA) are undertaken with varying the cutout size (diameter) as well as plate dimensions (plate aspect ratio and thickness). By the regression analysis of the FEA results obtained, a closed-form empirical formula for predicting the ultimate shear strength of perforated plates, which can be useful for first-cut strength estimations in reliability analyses or code calibrations, is derived. The accuracy of the ultimate strength formula developed is verified by a comparison with more refined nonlinear FEA results.     

铝制蜂窝夹芯板的强度特性

铝夹芯结构非常适合于设计飞机、高速列车和快艇等轻型交通系统。研究目的主要是明确包含铝蜂窝状内芯的铝制夹芯板在理论和试验中的强度特性。对弯曲、轴压和侧向撞击荷载作用下的铝蜂窝夹芯板构件进行了一系列强度试验。在相应荷载作用下,运用简化理论分析蜂窝夹芯板的弯曲变形、屈曲／极限强度和破坏强度。同时也讨论了结构失效模式,并给出了试验数据。     

Activation of nuclear factor of activated T cells-(NFAT) and activating protein 1 (AP-1) by oncogenic 70Z Cbl requires an intact phosphotyrosine binding domain but not Crk(L) or p85 phosphatidylinositol 3-kinase association

The Cbl proto-oncogene product is a complex adapter protein that functions as a negative regulator of protein tyrosine kinases. It is rapidly tyrosine-phosphorylated and associates with Crk(L) and p85 phosphatidylinositol 3-kinase (PI3K) upon engagement of numerous receptors linked to tyrosine kinases. Elucidation of the mechanism(s) underlying Cbl deregulation is therefore of considerable interest. The 70Z Cbl oncoprotein shows increased baseline tyrosine phosphorylation in fibroblasts and enhances nuclear factor of activated T cells (NFAT) activity in Jurkat T cells. Its transforming ability has been proposed to relate to its increased phosphotyrosine content. We demonstrate that 70Z Cbl shows increased basal and activation-induced tyrosine phosphorylation and association with Crk(L) and p85 PI3K in Jurkat T cells. 70Z Cbl, however, retains the ability to enhance NFAT and activating protein 1 (AP1) activity in the absence of Crk(L)/p85 PI3K association. In contrast, the G306E mutation, which inactivates the phosphotyrosine binding domain of Cbl, blocks NFAT/AP1 activation by 70Z Cbl. We conclude that 70Z Cbl-induced NFAT/AP1 activation requires the phosphotyrosine binding domain but not Crk(L)/p85 PI3K association. We hypothesize that 70Z Cbl acts as a dominant negative by blocking the negative regulatory function of the Cbl phosphotyrosine binding domain on protein-tyrosine kinases.     

Behavior of oxides in the liquid stainless steel

For a super clean steel, the oxygen content should be restricted to a very low level, and controlled during the melt state. The oxide behavior in an Al killed stainless steel melt were observed by analysing the forces exerted. New parameter, homogenization number (H number), was introduced to generalize the forces. Quantitative analysis of the removal of oxides was conducted, and a homogenization number was used to predict whether the oxides would be separated from the melt or mixed with the melt. It was also shown that the H number could possibly be used to estimate the capacity of oxide-absorption at the top slag.     

Antimicrobial activity of UV-irradiated nylon film for packaging applications

Antimicrobial packaging could enhance food storage life and safety. An antimicrobial moiety that is permanently bound to the polymer surface and does not leach has particular appeal. The use of 193 nm UV irradiation to convert amide groups on the surface of nylon to amines having antimicrobial activity has been reported previously. We prepared materials accordingly and explored their mode of action and activity against pathogens. Three food related bacterial strains, Staphylococcus aureus, Pseudomonas fluorescens and Enterococcus faecalis were exposed to antimicrobial film in 0.2 M sodium phosphate buffer (pH 7.0). Samples were held shaken at 100 r.p.m. in a 25°C incubator. The antimicrobial film was effective in reduction of microbial concentration in the bulk fluid for all food-related bacteria tested. The effectiveness was dependent on the bacterial strain. Adsorption of bacterial cells diminished the effectiveness of amine groups. Experimental results indicate that the decrease in concentration of bacterial cells in bulk fluid is more likely to be the bactericidal action than adsorption of live cells. © 1998 John Wiley & Sons, Ltd.     

Interphase cure characterization in epoxy composites by fluorescence technique

Monitoring the reaction of an aromatic diamine cure agent with epoxy by fluorescence technique was used for cure characterization of the interphase in epoxy/glass and epoxy/carbon composites. The effect of the various surface treatments was first studied by the model interphase obtained by using a quartz plate for glass or a modified quartz plate for carbon surface. Aminosilane treated quartz cured faster and showed increased cure extent, while water aging and air oxidation showed almost no effect on the cure kinetics in comparison to the untreated quartz surface. For a model carbon surface, air oxidation showed a faster reaction only at the early stage of cure. The effects of the various surface treatments on glass or carbon fiber were also studied with the actual composites made by a thin coating of epoxy-diamine melt on glass or carbon fiber bundles. Epoxy/glass fiber composite showed a similar trend as the model interphase system. In the case of epoxy/carbon fiber composite, both air oxidation and water aging treatment showed a faster cure reaction at the early stage of cure. Furthermore, air oxidation treatment for the epoxy/carbon fiber composite showed somewhat increased cure extent. The reasons for these trends have been discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1769–1775, 1997     

Fabrication and Characterization of Nanoscale Ferroelectric Honeycombs

Nanoscale ferroelectric honeycombs, comprised of vertically aligned PbTiO₃ nanotubes, are fabricated by vapor phase reaction between lead acetate‐infiltrated TiO₂ nanotubes and PbO vapor. PbTiO₃ nanohoneycombs converted by vapor phase reaction at 550°C showed well‐aligned nanoscale structure with alignment angle less than 1° and well‐defined ferroelectric properties with the effective piezoelectric coefficient of 44 pm/V. This novel nanoscale structure is expected to facilitate high efficiency sensing of electromechanical and electrochemical stimuli.     

Antioxidant and antigenotoxic effect of dairy products supplemented with red ginseng extract

The purpose of this study was to evaluate the antioxidant and antigenotoxic effect of dairy products milk (M) and yogurt (Y) after the addition of 2% red ginseng extract to milk (RM) and to yogurt (RY). Total phenolic content, total flavonoid content, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, oxygen radical absorbance capacity, and total radical trapping antioxidant potential were determined in the samples. Furthermore, antigenotoxic effect of samples was measured, using comet assay in human leukocytes. Total phenolic content and total flavonoid content of RM [38.3 ± 0.8 mg of gallic acid equivalents (GAE)/100 g, 23.6 ± 0.1 mg of quercetin equivalents (QE)/100 g] and RY (41.1 ± 0.9 mg of GAE/100 g, 18.7 ± 0.1 mg of QE/100 g), respectively, were higher than those of M (6.31 ± 0.2 mg of GAE/100 g, 10.4 ± 0.1 mg of QE/100 g) and Y (8.1 ± 0.9 mg of GAE/100 g, 8.4 ± 0.2 mg of QE/100 g), respectively. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and oxygen radical absorbance capacity values increased significantly after the addition of 2% red ginseng in both. Additionally, the total radical trapping antioxidant potential in RM (787.7 ± 7.0 μg/mL) was lower than in M (2074.0 ± 28.4 μg/mL). The H₂O₂-induced DNA damage in RY (0.1 ± 0.0 mg/mL) was less than the damage in Y (0.4 ± 0.0 mg/mL), but we found no significant difference between M and RM. This study indicates that supplementation with red ginseng can fortify the antioxidant and antigenotoxic effects of dairy products effectively.     

Thermal Stability of the Pigments Hydroxysafflor Yellow A, Safflor Yellow B, and Precarthamin from Safflower (Carthamus tinctorius)

ABSTRACT Three major yellow pigments were isolated from safflower petals ( Carthamus tinctorius ) and characterized as hydroxysafflor yellow A (1), safflor yellow B (2), and precarthamin (3) by ¹H-NMR, ¹H-¹H COSY, ¹³C-NMR, HMQC, and HMBC spectral analysis. Thermal degradation reactions of 3 yellow pigments 1 to 3 at temperatures of 70 to 90 °C were carried out at different pH levels within the range of 3.0 to 10.0 by UV-vis spectral measurements. First-order reaction kinetics was observed for the degradation of safflower yellow pigments (1 to 3) at pH 3.0 and 5.0. Activation energies of thermal degradation of 1-3 at pH 5.0 were calculated as 17.0, 15.4, and 20.1 kcal/mol, respectively. At neutral and alkaline conditions, yellow pigments 1-3 did not follow simple first-order kinetics.