Functional Properties of a Peptide of 23 Residues Purified from the Peptic Hydrolyzate of asl-CASEIN: Changes in the Emulsifying Activity During Purification of the Peptide

The pH 4.6-soluble fraction of the peptic hydrolyzate of as 1-casein contained the 23 N-terminal residues, αsl-CN(fl-23), as a major pep-tide. Reversed-phase HPLC indicated that small amounts of other peptides such as αsl-CN(f154-199) were also contained in this fraction. By removing of these peptides, the emulsifying activity (EA) of the αsl-CN(fl-23) fraction was markedly decreased. However, when the removed peptide fraction was added to the purified αsl-CN(fl-23), the EA was increased. Some synergistic effect in the emulsification seemed to exist between αsl-CN(fl-23) and the other peptides. Although the purified αsl-CN(fl-23) had low EA values at neutral pH levels, it showed high emulsifying and surface activities in the acidic pH region.     

EXTRACTION OF NIOBIUM AND TANTALUM WITH BIS-2-ETHYLHEXYL ACETAMIDE

ABSTRACT The extraction of Nb and Ta from acid solutions with bis-2-ethylhexyl acetamide and the stripping of these metals with sulphuric acid solutions were investigated. The organic phase was a binary solution of bis-2-ethylhexyl acetamide and xylene, while the aqueous phase was composed of hydrofluoric acid solution or hydrofluoric-sulphuric acid solution containing 3.5-13 Kg/m³ Nb and 5-10 Kg/m³ Ta. Sulphuric acid, hydrofluoric acid and nitric acid were used as salting out agents to understand the effect on the extraction.

Niobium and tantalum were not sufficiently extracted from hydrofluoric acid solutions, whereas the extraction of both metals remarkably increased with an addition of sulphuric acid to the aqueous phase. Both metals were completely co-extracted under the aqueous condition of 6N hydrofluoric acid and 8N sulphuric acid. The stripping occurred for both metals with high efficiency when water or dilute sulphuric acid was used as a stripping agent. The increase in sulphuric acid concentrations caused less stripping of Ta, while the stripping of Nb was maintained at 80% up to 7N sulphuric acid.     

Fatigue behaviour of cast magnesium alloy AZ91 microstructurally modified by friction stir processing

Friction stir processing (FSP) was applied to cast magnesium alloy AZ91-F to modify the as-cast microstructure, and the effect of FSP on fatigue behaviour was discussed based on microstructural consideration, crack initiation, crack growth behaviour, and fracture surface analysis. Fully reversed axial fatigue tests have been performed using as-cast, T5-aged and their FSPed specimens (as-cast/FSP and T5/FSP). It was found that both FSPed specimens exhibited significantly higher fatigue strength than the as-cast and T5-aged specimens. FSP resulted in the break-up of coarse as-cast microstructure, grain refinement of the matrix, finely dispersed precipitates and increase of hardness, thereby both the crack initiation resistance and the crack growth resistance were considerably enhanced compared with the as-cast and T5-aged specimens, resulting in the improved fatigue strengths of the FSPed specimens.     

高炉常用耐火材料导热系数的测定

采用激光脉冲法及使用DSC实测高炉用耐火材料的热扩散率及比热容,进而获得其导热系数.重点考察了温度及温度履历对耐火材料热扩散率及比热容的影响,得出二者与温度依存关系的数学模型,进而获得各种耐火材料的导热系数对温度的依存关系.测量结果表明:（1）除铝碳质耐火材料,其他耐火材料经一次高温后,测得的热扩散率值比第一次升温时的测得值增大,且温度特性随着温度变化呈现唯一的变化关系.而铝碳质耐火材料则相反,且随着升、降温过程的延续,热扩散率值逐渐减.（2）随温度的增加,比热容先较快增大后缓慢增加,温度履历对热容的测定基本没有影响.（3）根据测定结果,建立了导热系数λ（W/m·K）与温度T（K）之间的数学模型,经检验,该模型可有效地预测高炉常用耐火材料的导热系数.     

Allergic Skin Reactivity and Chemical Properties of Allergens in Two Grades of Lactose

Skin tests of the nondialyzable fraction of lactose were performed on patients with a clinical diagnosis of cow's milk allergy. The yields of brownish-colored residue, allergens (ALG), were 0.006% from reagent grade lactose (ALG 1) and 0.011% from lactose used in a commercial infant food formula (ALG 2). The ALG was separated into four fractions by chromatography on Sephadex G-75. The highest incidences of positive skin reaction among the four ALG 1 and ALG 2 fractions were 8/9 and 8/12 respectively. The ALG fractions were identified as a sugar protein complex and the protein moiety of ALG contained high amounts of glutamic acid (or glutamine), threonin, asparagic acid (or asparagine) and proline.     

Crack initiation from micro surface holes in bearings under rolling contact fatigue

Investigations concerning surface crack growth are necessary for understanding the mechanism of rolling contact fatigue (RCF) of bearings because the surface defects cause flaking failures. In the present work, micro holes were artificially made prior to the RCF tests and the initiation of the surface cracks from the micro holes was observed in order to find the key factors for understanding their features. Crack initiation directions were compared to the stress intensity factors calculated by a simple method based on the theory. The extent to which ‘contact pressure (wedge effect)’ and ‘contact stresses’ are applicable for understanding the correlations between the crack initiation directions and stress intensity factors is discussed. The crack initiation directions are strongly correlated to the stress intensity factors caused by the contact stresses alone. We concluded that the crack growth and initiation are dominated by stress intensity factors caused by contact stresses rather than the wedge effect.     

甘蔗渣的碱处理对其纤维增强全降解复合材料的影响

利用压制成型的方法制备了甘蔗渣纤维增强全降解复合材料, 探讨了碱处理对材料性能的影响。结果表明, 1 %碱液处理后材料的力学性能得到了提高。碱处理后纤维的分解细化和表面优化改善了纤维/ 基材的粘结性能, 从而使材料力学性能得到提高。而且, 处理后纤维拉伸强度和长径比的增大以及纤维缺陷的降低也会增强材料性能。      

Operation Planning for High Unit Utilization in Distributed Energy Management System with Storage Devices

Suppose a special district (group) that is composed of multiple companies (agents) imposed energy demand. We have proposed a distributed energy management system (DEMS) that optimizes energy consumption of a group through energy trading in the group. In this paper, we propose an efficient operation planning method for DEMS with storage device. At first, we formulate the optimization problem for agents. Second, we propose a method to search a unit commitment state that depends on group composition. We confirmed that the proposed method enables efficient use of generators in groups.     

Emulsifying Properties of an N-Terminal Peptide Obtained from the Peptic Hydrolyzate of αs1-Casein

A peptide corresponding to the 23 N-terminal residues of αs1-casein, αs1(1-23), was purified from a peptic hydrolyzate of αs1-casein. The emulsifying activity of αs1(1-23) varied depending on the concentration. When the concentration was higher than 2%, αs1(1-23) showed a similar emulsifying activity to αs1-casein in neutral pHs. The emulsion capacity of αs1(1-23) was about one half that of αs1-casein. The extent of adsorption of αs1(1-23) onto the oil globule surface was markedly high. In the acidic pH region (pH 5.5 – 3.0), αs1(1-23) maintained a high emulsifying activity, whereas αs1-casein lost its emulsifying activity. These results suggest that αs1(1-23) acts as an emulsifying agent and probably can be used in some foods such as processed cheese or fermented milk products.