Mikrobielle Werkstoffzerstörung – Schadensfälle und Gegenmaßnahmen für Kunst- und Naturstoffe: Mikrobielle Zerstörung von Kunststoffen

Microbial deterioration of materials – case histories and countermeasures for plastics and organic and natural materials: Microbial deterioration of plastics Large-scale production of synthetic plastics began in the thirties. The versatility of the new materials was enhanced by new processing technologies and above all by designing special formulations tailored to the different fields of applications. Their increasing universal application was, however, also accompanied by growing records of documented microbial attack. The mechanisms of attack have largely been identified. Damage is commonly caused by surface growth, discolourations and changes of mechanical and electrical properties. National and international test standards have been developed to predict the service life of certain plastics or to evaluate the protection afforded by certain biocides. Several standard methods of test are presented and the criteria for evaluation are critically examined. Finally, the activities of the Plastics Project Group are represented, wich has carried out several international co-operative tests to evaluate the reproducibility of the results of different test methods and has worked out recommendations and improvements.     

Synthesis of fine composite particles for hydrogen storage, starting from Mg-YNi2 mixture

We synthesized new composite particles for hydrogen storage on the basis of an idea of “particle designing”. As starting materials, powders of Mg and YNi₂ were selected. Fine composite particles containing mainly Mg₂Ni could be designed by repetitive hydriding and dehydriding cycles at 673 K. In the synthesis process of the composite particles, the following two points were found to be essential for this technique. The first point is that, after being activated by the sequential processes of hydrogenation, amorphization and disproportionation, YNi₂ reacts effectively with Mg. The second point is that evaporated Mg, which occurs during dehydriding, adheres to the surface of the activated YNi₂ and accelerates a diffusion reaction to form Mg₂Ni at the interface. In these composite particles, Mg₂NiH₄ is formed, even at 373 K, under a hydrogen pressure of 5 MPa.     

Evolution of BET internal surface area in glassy carbon powder during thermal oxidation

It is demonstrated that glassy carbon powder can be thermochemically activated. During activation, a film with open pores is created on the glassy carbon particles. This film has a large internal surface area, which is accessible to liquids and gases. A simple model for the evolution of the internal surface area in glassy carbon powder during thermochemical gas-phase oxidation is also presented and compared with experimental data. Experimental results are in qualitative agreement with the model. We found that a sharp particle size distribution is desirable with regard to potential technical applications.     

A problem of pursuit and evasion

A trajectory problem of pursuit and evasion on a plane is considered for the case of equal absolute velocities of the players. Exact solutions are obtained for fixed initial conditions.Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 138–143, May–June, 1992.     

Bisensors for amino acids

Two kinds of biosensors for amino acids (one with nonspecific enzyme as bioelement, the other with specific enzyme(s) as bioelement), including their principles, applications, recent researches and future trends were discussed in detail. 61 references were given. A part of work for gaining Ph. D in chemical and biochemical application at FPMs (Mons, Belgique) Synopsis of the first author Xia Jinlan, Male, born in 1963, now at Facult’e Polytechnique de Mons, Belgique     

The Principles of Calculus of Behavior Scenarios of Complex Systems in the ECS

Theoretical results of the development of the principles of scenario calculus are presented, which are obtained in the framework of the design of an emergency control system (ECS). Relying on the suggested system concept of the formation of a scenario system, consideration is given to the principles of the construction of operations in scenario spaces, which account for specific features of the scenario analysis and the process of the decision-making in the ECS. Principal problems of the development of scenario calculus on the basis of a system approach are treated, the classification of operations on scenarios is given, and a number of operations on elements of the basic metacollection are formalized.     

Measuring probe for fast transients monitoring in gas insulatedsubstation

This paper describes the construction of four probes adjusted for fast transient monitoring in 123 kV SF₆ insulated substations. The primary requirement was the ability to monitor without distortion very fast transients containing frequencies up to 200 MHz. The measuring system was tested and calibrated with the help of computer modeling techniques. The verified experimental apparatus was then used for testing and calibrating the measuring probes. During the test, various effects on the measuring system characteristics were analyzed with respect to materials used for the components of the system     

Psychiatric evaluation in accordance with the transsexualism regulation. An experience-based plea for guidelines and against arbitrary bias

Today patients want to change their Christian names not so much for social support but in order to obtain sex change operations. For this reason among others we caution against casual and careless evaluations and plead for conscientiousness and thoroughness. The spectrum of 16 evaluation cases in the year 1995 is presented. Following this and looking for guiding principles, the most important aspects are discussed: the dilatable frame of the written law, the examiner's diagnostic process, the duty of being well informed, reconstruction of development as the first goal of examination, real-life self-testing and therapy, the obligation to report one's own findings, change of Christian name and indication of operation, evaluation for gender changing, problems of the judge-expert relationship and of future development.     

Optimality of the sequential probability ratio test fornonstationary observations

Bayesian analysis is used to show that Wald's sequential probability ratio test with varying thresholds is optimal for the nonstationary situation, where the observed samples are independent but not identically distributed. Some important properties useful for the design of the test thresholds are discussed. Wald's lower bound, generalized to the nonstationary situation, is also presented. The results have important applications in situations where the observed signal is time-varying. such as in radar signal processing, image processing, and spread spectrum communications