Characterization of plasma electrolytic oxide formed on AZ91 Mg alloy in KMnO4 electrolyte

The aim of this work is to investigate microstructure, corrosion resistance characteristics and nanohardness of the oxide layer on AZ91 Mg alloy by applying different voltage with KMnO₄ contained solution. There are lots of closed pores that are filled with another oxide compound compared with the typical surface morphology with pore coated until 350 V of coating voltage. The thickness of oxide layer increases with increasing coating voltage. The oxide layer formed on AZ91 Mg alloy in electrolyte with potassium permanganate consists of MgO and Mn₂O₃. Corrosion potential of the oxide layer on AZ91 Mg alloy obtained at different plasma electrolytic oxidation(PEO) reaction stages increases with increasing coating voltage. The corrosion resistance of AZ91 Mg alloy depends on the existence of the manganese oxide in the oxide layer. The inner barrier layer composed of the MgO and Mn₂O₃ may serve as diffusion barrier to enhance the corrosion resistance and may partially explain the excellent anti-corrosion performance in corrosion test. Nanohardness values increase with increasing coating voltage. The increase in the nanohardness may be due to the effect of manganese oxide in the oxide layer on AZ91 Mg alloy coated from electrolyte containing KMnO₄.     

IDENTIFICATION OF HURDLES FOR IMPROVING STORAGE STABILITY OF BRAISED KIDNEY BEANS, A KOREAN SEASONED SIDE DISH

The aim of this study was to identify factors affecting the preservation of braised kidney beans, a traditional Korean side dish, to extend its shelf life. The effects of ingredient formulation, refrigerated storage and modified atmosphere packaging on storage stability and/or sensory quality were examined. Count of yeast/mold was selected as a primary quality index from the storage test at 10C. A formulation was found in cooked kidney beans, sugar, soy sauce and corn syrup to provide the retarded microbial growth and affordable sensory quality. The temperature dependence value (Q₁₀) for the shelf life of the stretch-wrapped product was 2.0 for temperatures of 5 to 20C. Modified atmosphere packaging (60% CO₂/40% N₂ or 100% CO₂) extended the shelf life at 10C by 500% (to 36 days) compared to air packaging (6 days) based on criteria of yeast/mold growth. Equations for estimating microbial spoilage and shelf life were derived as function of temperature.

PRACTICAL APPLICATIONS

Microbial growth retardation by ingredient formulation change, chilled storage and high CO₂ modified atmosphere packaging is useful to design the processing, packaging and distribution of the Korean side dish product. Quality change kinetics of yeast/mold growth established can be used for determining shelf life of the product under different storage temperature conditions. Through the scale-up procedure, the knowledge found in this study will be useful for the industrial processing and storage of the seasoned side dishes.     

Low cycle fatigue properties and cyclic deformation behavior of as-extruded AZ31 magnesium alloy

The low cycle fatigue(LCF)properties of as-extruded AZ31 Mg alloy were investigated under total strain amplitudes in the range of 0.4%-1.2%with strain rate of 1×10- 2s -1.Due to the twinning effect in compression during loading and the detwinning effect during unloading,the alloy showed an asymmetric hysteresis loop.The cyclic stress response exhibited cyclic hardening at high total strain amplitudes.The cyclic deformation behaviors were discussed using the Coffin-Manson plot,which divided the plastic strain amplitudes into the tension side and the compression side.Through the LCF tests that were started from either tension or compression under a total strain amplitude of 1.0%,the interaction between the twinning effect and dislocation was analyzed.The twinning effect during the LCF test and the variation of the dislocation density were investigated using optical microscopy and transmission electron microscopy,respectively.     

Nutritional Evaluation of the Protein in Oilseed Products Heated with Sugars

Defatted flours and protein isolates from glandless cottonseed, peanut, and soybean were complexed with glucose or sucrose in a ratio of 1:1 by weight and heated at 100°C for 0, 2, or 6 hr. Quality changes by the heat treatment were assessed by determining the extent of browning (browning index), in-vitro protein digestibility, available lysine total amino acids, and computed protein efficiency ratio (C-PER). Whereas the sucrose-containing complexes changed very little in all the quality parameters determined, the counterparts containing glucose decreased substantially in protein quality along with the increased intensity of browning. Before heating, protein digestibility of the complex containing defatted flour of an oilseed was lower than that of the isolate counterpart. When heated, however, the isolate-glucose complexes decreased more in protein digestibility than the flour-glucose complexes. The available lysine content decreased by 76-83% for the complexes with glucose in contrast with 2-10% for those with sucrose. As to total amino acids, marked losses in arginine, lysine, tryptophan, and histidine were found in the complexes containing glucose, with the arginine loss as high as the lysine loss. Lysine-rich soy proteins lost lysine in greater percentages than lysine-poor peanut and cottonseed proteins. C-PER decreased by 63-86% in the glucose-containing complexes, with the highest decrease shown for soy flour-glucose. In-vitro protein digestibility, available lysine, and C-PER were all highly correlated (P < 0.01) with browning index. Available lysine was also highly correlated with C-PER.     

Hydrolytic Stability and Changes in E Vitamers and Oryzanol of Extruded Rice Bran During Storage

Rice bran was extruded at 110, 120, 130, and 140°C with post extrusion holding times of 0, 3, and 6 min and stored at ambient temperatures for 1 yr. Holding time had no effect (p>0.05) on hydrolytic stability whereas 110°C was slightly less effective in maintaining hydrolytic stability. Increased holding times reduced (p<0.05) total vitamin E content. Oryzanol concentration was lower (p<0.05) only after 6 min holding time. Oryzanol was relatively more stable to extrusion temperatures than vitamin E. The highest retentions of total vitamin E and oryzanol were found in raw rice bran during storage. Increased extrusion temperatures reduced the retention of vitamin E and oryzanol during storage.     

An evaluation of the influence of impurity concentration and composition in concrete on activation and radiation dosein the reactor facility

The content analysis of radioactive waste and radiation dose evaluation is considered as one of the important factors in the reactor facility design.This kind of buildings consists of the concrete for the most part and uses it as the structure and shield of the building.Generally,the concrete has impurities such as cobalt,europium,nickel,and cesium with specific content depending on the production method or manufacturing company.Dominant radioactive nuclides generated from the fundamental compon...     

Ni-25%Al合金中稳态至亚稳态共晶生长的结构转变(英文)

在10-100μm/s的生长速度范围,热梯度为10 K/mm的情况下,研究Ni-25%Al(摩尔分数)合金定向凝固的微观结构演变规律。凝固组织显示了γ’-β平衡共晶相向γ-β亚稳态共晶加β枝晶相的转变。在25μm/s的生长速度时生成的γ’-β和γ-β共晶的混合微观组织表明转变发生在γ和γ’相之间的竞争生长期间。在凝固期间选取微观结构时应考虑各个相的生长温度,试验结果显示在给定生长速度的情况下,在凝固期间,应优先选择在最高温度固化的某个相或微观结构。而且,在25-60μm/s的生长速度范围内,由于稳态和亚稳态共晶具有相似的生长温度,因此可以共存且同时生长。     

Study on Construction of Industrial Large‐Scale Battery System

This paper proposes a construction method for battery systems that are widely used in industries. The battery system uses a building block structure combined with a battery module, whose capacity is less than 1 kWh. To manage the building block structured system, we propose a hierarchical structured management method. In each hierarchy, the voltage and temperature of the battery are monitored, and the information necessary for calculating charge states and detecting faults are sent to the upper hierarchy for the state management of the lower hierarchy. Furthermore, to ensure the safety during maintenance activities, we provide a guidance for understanding the insulation structure for the battery module, and develop a ground fault detection method that detects a decline in the insulation performance by using a rising method. For the experiment, we use a 30‐kWh trial manufacture battery system combined with the hierarchical management method. We verify that charge states and faults are detected in the battery of the system, and confirm that the system can be charged and discharged safely.     

Antioxidative Effect of Ascorbic Acid Solubilized in Oils via Reversed Micelles

Ascorbic acid was solubilized in oils via reversed micelles using phosphatidyl choline as surfactant and water. The effect of the solubilized ascorbic acid on the oxidative stability of fish and soybean oils was investigated in terms of peroxide value in the absence and presence of rosemary extract or δ-tocopherol. The autoxidation of the oils was greatly retarded with the ascorbic acid compared to the natural antioxidants used. The ascorbic acid also exerted a synergistic effect with δ-tocopherol in fish oil.     

Thermal Sterilization of Conduction-Heated Foods in Plastic Cylindrical Cans Using Convective Boundary Condition

A mathematical model was developed to evaluate thermal processing of foods in cylindrical plastic cans. This model included convective heat transfer coefficients for heating and cooling media, thermal diffusivities of plastic can wall and the canned food, and contact conductance between the plastic wall and the canned food. Temperatures estimated by the model at the coldest point in a can agreed closely with those determined experimentally during thermal processing. Thermal diffusivity of can wall and heat transfer coefficients of heating and cooling media considerably influenced the sterilizing values of the processed food.