Non-isothermal crystallization kinetics of Ag-As2S3 semiconductor glasses

Using a differential thermal analysis technique to give single scan thermograms, the transformation mode,n, and the activation energy of crystallization,E, were determined for the chalcogenide glasses of the system Ag _x (As₂S₃)_100–x' withx=6, 15 and 25. Bothn andE were found to be compositionally dependent. The value ofn varies between 2.1 and 3.6, and that ofE between 2.4 and 3.6 eV. The crystallization kinetic data were explained using X-ray diffraction results of amorphous and crystalline structures.     

Influence of composite materials confinement on alkali aggregate expansion

The Alkali-Aggregate Reaction (AAR) is a group of physicochemical reactions which occurs in the concrete between the interstitial solution (highly alkaline) and some mineral phases in the aggregates. The damage induced by the AAR to the concrete could be very important. Many old structures are attacked or will be attacked by AAR. Remedial measures to repair or limit the problem exist but they are often only partially effective and very expensive. The aim of our research is to carry out an experimental procedure in order to evaluate the influence of advanced composite materials confinement on the expansion and the mechanical behaviour of the alkali-aggregate reactive concrete.

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Résumé L'alcali réaction est un ensemble de réactions physico-chimiques dans le béton qui peuvent se produire entre la solution interstitielle (fortement alcaline) et certaines phases minérales présentes dans les granulats. Les dommages causés au béton par l'alcali réaction peuvent être très importants. Beaucoup de structures sont attaquées ou le seront par l'alcali réaction. Les remèdes pour réparer ou diminuer l'alcali réaction existent mais ils sont souvent peu efficaces et très chers. Le but de notre travail de recherche est d'évaluer expérimentalement l'influence des matériaux composites sur l'expansion et le comportement mécanique du béton alcali-réactif.

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Editorial note Prof. Patrice Hamelin is a RILEM Senior Member. He participates in the work of RILEM TC TRC ‘Textile reinforced concrete’.     

IR spectroscopic study on the thermal degradation of plastic security cover sheets of some documents

The change in IR spectra of plastic security cover sheets of ethylene vinylacetate copolymer during thermal treatment was investigated. The results obtained revealed that the temperature reduced the concentration of the ester group; moreover, the carbonyl band disappeared at high temperatures from 200 to 220°C, as well as broading of the absorption aliphatic–CH band. The change in the mechanical properties, degree of swelling in water, and refractive index of the samples during thermal treatment were also investigated. © 1993 John Wiley & Sons, Inc.     

Optimization of black oxide coating thickness as an adhesion promoter for copper substrate in plastic integrated-circuit packages

Copper-oxide coating applied onto the copper substrate has emerged as an alternative to metallic coatings to improve adhesion with polymeric adhesives and molding compounds. The interfacial-bond strengths between the black oxide-coated Cu substrate and epoxy-based, glob-top resin were measured in button-shear tests, and the failure mechanisms were identified from the fracture-surface examination. The emphasis was to establish the correlation between the coating thickness, the surface roughness, and the interfacial adhesion with respect to treatment time. It was found that at the initial stage of treatment a thin layer of flat, cuprous oxide developed, above which fibrillar-cupric oxide was formed with further treatment until saturation with densified fibrils at about 150 sec. The interfacial-bond strength between the oxide-coated copper substrate and glob-top resin increased gradually with increasing treatment time, until the bond strength reached a plateau constant after a treatment for about 150 sec. There was a functional similarity between the oxide thickness, the surface roughness, and the interface-bond strength with respect to treatment time. A treatment time of 150 sec is considered an optimal condition that can impart the highest interface adhesion.     

去除光刻胶的新干法工艺

除去干刻或高剂量等离子注入后的光刻胶，一般是采用化学溶剂和酸类等湿刻法，以前有时采用干燥氧的等离子灰化法，然而成本高，具有危险性和污染性的化学湿刻法直接造成了环境污染，使得全球气候变暖，能源的大量消耗，地下水受到污染等等，一种新的干式去胶并且处理后可用去离子水DI清洗残留物的工艺方法（ENVIRO）已经在半导体芯片厂被成功地使用了12个多月。对于产量10000片／周的芯片厂，相对于化学湿刻法一年可以节省5百万美元溶剂消耗。     

Tight bounds for the identical parallel machine-scheduling problem: Part II

A companion paper introduces new lower bounds and heuristics for the problem of minimizing makespan on identical parallel machines. The objective of this paper is threefold. First, we describe further enhancements of previously described lower bounds. Second, we propose a new heuristic that requires solving a sequence of 0–1 knapsack problems. Finally, we show that embedding these newly derived bounds in a branch‐and‐bound procedure yields a very effective exact algorithm. Moreover, this algorithm features a new symmetry‐breaking branching strategy. We present the results of computational experiments that were carried out on a large set of instances and that attest to the efficacy of the proposed algorithm. In particular, we report proven optimal solutions for some benchmark problems that have been open for some time.     

Producing robust use case diagrams via reverse engineering of use case descriptions

In a use case driven development process, a use case model is utilized by a development team to construct an object-oriented software system. The large degree of informality in use case models, coupled with the fact that use case models directly affect the quality of all aspects of the development process, is a very dangerous combination. Naturally, informal use case models are prone to contain problems, which lead to the injection of defects at a very early stage in the development cycle. In this paper, we propose a structure that will aid the detection and elimination of potential defects caused by inconsistencies present in use case models. The structure contains a small set of formal constructs that will allow use case models to be machine readable while retaining their readability by retaining a large degree of unstructured natural language. In this paper we also propose a process which utilizes the structured use cases to systematically generate their corresponding use case diagrams and vice versa. Finally a tool provides support for the new structure and the new process. To demonstrate the feasibility of this approach, a simple study is conducted using a mock online hockey store system.     

Antioxidant and free radical-scavenging activities of smooth hound (Mustelus mustelus) muscle protein hydrolysates obtained by gastrointestinal proteases

We have investigated the antioxidative activity of five hydrolysates from smooth hound (Mustelus mustelus) meat obtained by various gastrointestinal proteases: crude enzyme extract, low molecular weight (LMW) alkaline protease and trypsin-like protease from M. mustelus intestine, pepsin from M. mustelus stomach, and bovine trypsin.     

Numerical study of compact shear (Mode II) type test specimen geometry

The Iosipescu shear test specimen geometry has been investigated by a number of research workers in recent years with conflicting results. The paper describes a numerical study of a compact shear test specimen, based on the Iosipescu geometry, which is proposed to investigate size effects in shear failure. A range of geometries has been studied and the extreme cases are reported. Results are presented for the largest absolute principal stresses together with a detailed study of the stresses between and around the roots of the two notches introduced in the test specimens. The results for the largest absolute principal stresses show that tensile stresses are created at the roots of the two notches. These tensile stresses may result in Mode I failure and probably account for the Mode I or mixed mode fracture observed in tests using the Iosipescu geometry. The results for the distribution of stresses between the roots of the two notches show that deep notches increase the likelihood of shear fracture prior to tensile failure. Shallow notches give a stress distribution similar to that developed in the indirect tensile test and hence tensile failure is likely to precede shear failure in such cases. Further numerical and experimental work is proposed.      

Effects on Phase Transitions in Tripalmitin due to the Presence of Dipalmitin,Sorbitan-Monopalmitate or Sorbitan-Tripalmitate

The effects of diglycerides, sorbitan-monoesters and sorbitan-triesters on triglyceride polymorphic transitions have been examined. Earlier reported effects of retardation of β' ← transitions due to the presence of asymmetric diglycerides were found to be the same from the racemic and antipode forms. The α ← β and β' ← β transitions of tripalmitin (PPP) were followed when sorbitan-monopalmitate (SMP), sorbitan-tripalmitate (STP), or dipalmitate (DP) were present. The STP gave a slightly stronger reduction in transition kinetics than DP, whereas SMP was found to promote the transition. In order to understand the mechanisms involved the binary systems SMP-PPP and STP-PPP were examined. In the case of SMP-PPP a 1:1 molecular compound is formed, whereas STP-PPP a 1:1 molecular compound is formed, whereas STP-PPP shows a simple eutectic behaviour.