On stress-relaxation experiments and their significance under strain-aging conditions

Two simple tests are presented to verify whether the mechanical response of the substructure remains constant during stress relaxation. They consist of a) subjecting the sample to repeated relaxation cycles from the same reference load and b) reloading the sample after the last cycle. Either exhaustion of relaxation after repeated cycles or yield-point formation on reloading are indicative of a decrease in the mobile dislocation density. Accordingly, a method is developed for the determination of the time dependence of the mobile dislocation density, using the decrease in relaxation rates in repeated cycling. The exhaustion of relaxation in Armco iron is found to be in good agreement with predictions for the decrease of mobile dislocation density by a pinning mechanism.     

Cloning of the Multicopy Suppressor Gene SUR7: Evidence for a Functional Relationship between the Yeast Actin-binding Protein Rvs167 and a Putative Membranous Protein

The rvs161 and rvs167 mutant cells exhibit several identical phenotypes including sensitivity to several different growth conditions and morphological defects such as alteration of the actin cytoskeleton and budding patterns. The selection of genes that, when overexpressed, are able to suppress the reduced viability upon carbon starvation of the rvs167 mutant strain, has allowed the cloning of the SUR7 gene (Accession Number Z46729x11). We showed that the suppressive ability of the overexpressed SUR7 gene concerns all the rvs167 phenotypes. However, this suppression is only partial since the rvs167-suppressed strain is not of wild-type phenotype. Moreover, SUR7 is also able to suppress partially the phenotypes exhibited by the rvs161 and rvs167 rvs161 mutant strains. The SUR7 gene encodes a putative integral membrane protein with four transmembrane domains. Furthermore, sequence comparisons revealed that Sur7p and two other proteins, Ynl194p and Ydl222p, present significant sequence and structural similarities. Taken together, these results strongly suggest that the Rvs161 and Rvs167 proteins act together in relation with Sur7p. Moreover, the putative transmembranous character of Sur7p suggests a membrane localization of the Rvs function, a localization which is consistent with the different rvs phenotypes and the actin–Rvs167p interaction. © 1997 John Wiley & Sons, Ltd.     

漫步 “漫游之形”户外装置

<正>"漫游之形"户外装置坐落于美国坦帕市滨河公园与河道相接的休闲区,作为坦帕最活跃的河滨区域的新纪念场所,也可以用来举行户外公共活动。装置形如倒置的红树,绿色的铝制棚架作为希尔斯堡河的标志,立于棕榈树之中。树状结构仿佛浮于水陆之间。     

EFFECT OF DIFFERENT COATING TREATMENTS ON THE QUALITY OF MANGO FRUIT

Eight coating formulations were evaluated for beneficial effects on the shelf‐life of mangoes (cvs. Kent, Tommy Atkins, and Lirfa) harvested at different maturity stages. Four coatings were then selected for further study under various conditions of storage including ambient (19–22C and56–60% RH) and simulated commercial (12C and 80% RH) storage. The four coating formulations contained carnauba wax, shellac, zein, and/or cellulose derivatives. All coatings reduced the respiratory rate, the development of external and internal color, and all but carnauba wax retarded the loss of firmness. Changes in acids were also delayed in all coated mangoes. Based on these parameters, fruit maturation was estimated to have been delayed by a few days compared with uncoated fruit. Shellac and cellulose‐based coatings, however, caused elevated levels of ethanol, although this did not lead to significant flavor differences from the control (uncoated fruit) in sensory tests. Only the carnauba wax coating was an effective water loss barrier under conditions of high RH.     

Coordination, Organizational Boundaries and Fads in Business Practices

Management literature focuses on two modes of coordination:formal and informal structures. Informal structure grants significantdiscretion to individual actions. Yet two impediments are relatedto such flexibility, those created by opportunism and thosecreated by convergent expectations. Impediments arising fromconvergent expectations exist when the expectations of all membersof an interdependent system are not properly aligned. We usenon-cooperative game theory to provide a foundation for thestudy of convergent expectations. We argue that the incentiveto free-ride on the contributions of others is not a necessarycondition for generating a lack of convergent expectations,and apply the issue of convergent expectations to both the organizationalissues of optimal group and firm boundaries and to the roleof managerial practices such as Total Quality Management (TQM).Building on research from organization theory, social psychologyand game theory, the paper ties the idea of convergent expectationsto the grouping dilemma of the trade-off between higher coordinationwithin groups and lower coordination between groups. We arguethat this grouping dilemma can serve as a basis for determiningthe actual boundaries of both groups in organizations and theorganization itself. Examining the role of fads in businesspractices, we conclude that, however suspect their underlyingvalue as decision aids may be, these practices can serve asuseful coordination mechanisms.     

COMPARATIVE STUDY OF TEXTURE TERMS: ENGLISH,FRENCH, JAPANESE AND CHINESE

ABSTRACT

Texture vocabularies in English, French, Japanese and Chinese languages are examined, and their characteristics are described. It wasconfirmed that most frequently used texture vocabularies concern with the mechanical and geometrical properties, and are used to describe solid‐like foods rather than liquid‐like foods. It was also shown that in all the languages, the terms used by texture experts and consumers are different. Complete agreement was not recognized even among texture experts, although it is expected that the validation of most fundamental terms could be reached through discussions. Further detailed comparison is now in progress.

PRACTICAL APPLICATIONS

In the globalization age, it is becoming more and more important to understand different languages representing texture of foods. Therefore, it is useful to compare the texture terms in different languages both for academic researchers and workers in the trade and industries.     

Using the Kanban in a job shop environment

Japanese industrial management techniques have been applied in a large number of large Western enterprises. In particular, the Kanban method has been used to control materials, production rate and volume, and to adjust production to requirements. The authors show how the Kanban method may be adapted to the job shop. This adaptation was extensively tested through simulation and then implemented. Actual performance is consistent with the simulation results, and shows marked improvement over previous practice.     

THERMAL INACTIVATION KENETICS of PECTINESTERASE EXTRACTED FROM ORANGES

A study was carried out on the kinetics of thermal inactivation of pectines terase (PE), extracted from the pulp of Valencia and Navel oranges. Moreover, the influence of intrinsic factors on the kinetics of Navel orange PE was investigated. In a citric acid buffer, at a pH of 3.7 and 4.2, the enzyme was more thermostable as compared to water. However, at pH 3.2 an increased inactivation and an increased temperature sensitivity of the rate constant was observed. Ca²⁺-ions also enhanced the inactivation, whereas the temperature sensitivity of the rate constant decreased. In presence of sucrose, a diminished inactivation of PE was observed, and addition of sucrose only slightly influenced the activation energy.     

AN OPTICAL METHOD TO STUDY THE KINETICS OF CLEANING MILK DEPOSITS BY SODIUM HYDROXIDE

An optical sensor was devised to observe cleaning kinetics of heat exchange surfaces fouled by milk and to study the influence of some parameters on them. The sensor works by sensing the attenuation of incident light by the suspension of deposits which are removed by the cleaning solution. The cleaning is carried out without recycling the cleaning solution. The on-line collected numerical data are converted into concentration values by the use of an empirical correlation based on samples of freeze dried deposits diluted with soda solutions. The cleaning kinetics and the weight of removed fouled material are computed for each experiment by integrating the concentration versus time curve. Over 20 experiments, carried out on a plate milk pasteurizer have established the validity of the method. The kinetics are interpreted as initially zero order, but first order at the end of the process.