Metamodeling live sequence charts for code generation

This article presents a metamodeling study for Live Sequence Charts (LSCs) and Message Sequence Charts (MSCs) with an emphasis on code generation. The article discusses specifically the following points: the approach to building a metamodel for MSCs and LSCs, a metamodel extension from MSC to LSC, support for model-based code generation, and finally action model and domain-specific data model integration. The metamodel is formulated in metaGME, the metamodel language for the Generic Modeling Environment.

Evolution of laser-produced plasma in an external magnetic field

The evolution of laser-produced plasma in an external magnetic field was studied. Equations of ideal MHD in a cylindrical coordinate system were solved numerically by using the conservative TVD difference scheme of second order in time and space. At the beginning, a short 30-ns laser pulse with the Gaussian transverse intensity distribution with a half-width of 0.03 cm was applied to heat the target that consisted of aluminum vapor plasma. The cases of weak (plasma parameter β = 1) and strong (β = 0.026) external magnetic fields were considered. The results of the numerical calculations show that the magnetic field increases the width of the laser plume’s front and forces plasma to move predominantly along the magnetic field lines. An increase of the magnetic field strength resulted in increased inhomogeneity of temperature and density distributions in the laser plume volume. The model shows that in the final stages of evolution the laser plasma takes the form of a confined jet aligned along the symmetry axis.     

Controller design for flexible structure vibration suppression with robustness to contacts

Model-based feedback control of vibration in flexible structures can be complicated by the possibility that interaction with an external body occurs. If not accounted for, instability or poor performance may result. In this paper, a method is proposed for achieving robust vibration control of flexible structures under contact. The method uses robust linear state feedback, coupled with a state estimation scheme utilizing contact force measurement. Uncertain contact characteristics are modelled by a sector-bounded non-linear function, such that state feedback gains can be synthesized using a matrix inequality formulation of the Popov stability criterion. A separation theorem is used to establish a robust H₂ cost bound for the closed loop system. Experimental results from a multi-mode flexible structure testbed confirm that vibration attenuation and stability can be maintained over a broad range of contact characteristics, in terms of compliance and clearance.     

Temperature measurements using a birefringent sensor

An optical method for temperature measurements is proposed based on the use of an autocollimation polarimeter and a sensitive birefringent plate. The basic expressions that describe the operation of the system are presented. It is shown that with the use of a quartz plate 1.5 mm thick the device makes it possible to determine values of temperature in the region of –80 to +150°C.Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer of the Academy of Sciences of Belarus, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 5–6, pp. 475–482, November–December, 1994.     

Comparative value of skin tests and IgE antibodies in the serum in patients with chronic vasomotor rhinitis

In order to assess values of skin testing and determination of pulp, as a credible indicator considering sensibilisation of an organism, 61 patients suffering from chronic vasomotor rhinitis were tested. By application of "prick" test, skin test results were positive in 30 patients and negative in 31. Presence of specific IgE antibodies in the serum was assessed in all patients by "ELISA" test. In 51 patients (83.6%) both kinds of findings corresponded. In 26 patients both skin parameters were negative while in 10 patients (16.40%) findings did not correspond. It was established that for Dermatophagodies pteronyssinus specific IgE antibodies are determined in serum when pap is 5 mm wide. Grasp pollen always caused strong local reactions, regularly more than 10 mm. Considerably high levels of IgE antibodies was also established while other pollens did not show such correspondence.     

Subacute Plasmodium falciparum malaria in 43 patients returning from areas with chloroquine in Africa

PURPOSE: To identify clinical and biological features of subacute falciparum malaria, risk factors, and to evaluate the efficacy of curative treatment. PATIENTS AND METHODS: Diagnostic criteria were the association of apyrexia, anemia, little or no parasitemia and a high titer of anti-Plasmodium antibodies. Forty-three cases were observed in subjects returning from chloroquine-resistant areas in Africa. They were matched with controls for age, country of residence and duration of stay. Controls were missionaries who attended our unit for a routine medical check-up during the study period. RESULTS: The clinical presentation and biological features were similar to "malarial cachexia", a condition mainly described in non-immune children in endemic areas. Splenomegaly was present in 58% of the patients. Biological features included little or no parasitemia, an overall decrease in the blood cell count, an increased erythrocyte sedimentation rate and a high titer of anti-Plasmodium antibodies. This syndrome was not correlated with the frequency of chloroquine resistance, the area of stay (urban or rural) or to the kind of chemoprophylaxis. CONCLUSIONS: This study describes subacute resistant falciparum malaria in patients who had prolonged stay in chloroquine-resistant areas of Africa associating splenomegaly, cytopenia and a low or absent parasitemia. Subacute chloroquine-resistant malaria could be due to host factors which remained to be determined by prospective immunological studies. Curative treatment with mefloquine is effective.     

The nature of temper brittleness of high-chromium ferrite

The reasons for development of 475°C brittleness of high-chromium ferritic steels are considered from the standpoint of fracture mechanics. It is shown that the general rise in the curve of temperature-dependent local flow stress has the decisive influence on the position of the ductile-to-brittle transformation temperature and the increase in it as the result of a hold at temperatures of development of brittleness. The established effect is related to the change in the parameters determining dislocation mobility, that is, the activation energy of dislocation movement in high-chromium ferrite and the resistance to microplastic deformation, both caused by processes of separation into layers of high-chromium ferrite and decomposition of the interstitial solid solution.Translated from Problemy Prochnosti, No. 7, pp. 71–75, July, 1994.     

Double torsion fracture testing of high-density polyethylene

The fracture of polyethylene has been studied extensively using conventional testing geometries such as three-point bending (TPB) and single-edge notch tension (SENT). These geometries are of limited utility for studying crack growth, because the crack speed is constantly changing and the crack front is in the centre of the specimen. Double torsion (DT) is a fracture geometry that suffers neither of these disadvantages, yet has only received limited attention in the literature. Its use has been limited to highly brittle materials such as glass, ceramics, thermosetting plastics and PMMA. In contrast to these materials, high-density polyethylene (HDPE) is an inherently ductile polymer. Before the advantages of DT can be exploited for testing HDPE, it is first necessary to demonstrate the validity of DT fracture measurements performed on such a ductile material. In this paper it is shown that at moderate rates of loading and at temperatures below 0C, valid double torsion fracture results can be obtained for an ethylene 1-butene copolymer. A novel technique for specimen preparation and a simple method for accurately monitoring crack growth are also described.     

Temperature and wavelength dependent transmission of optically transparent glass fibre poly (methyl methacrylate) composites

The temperature and wavelength dependent transmission was measured for glass fibre reinforced transparent composites prepared by sheet lamination and pressure curing processes. A mathematical model using fibre volume content, glass fibre diameter, refractive index of the fibre and matrix, non-wet fibre content and thickness of the composites was used to predict the transmission of the composite as a function of temperature and wavelength. The transmission calculated from the model for 20–70 °C and between 500 to 800 nm agreed well with the measured optical transmission for a thin composite containing < 10 vol % of 17 m glass fibres. A small amount of non-wet fibre (e.g. 2.0% of total fibre) was predicted to reduce the maximum transmission by up to 17% for a composite containing 7.2 vol % fibres and a thickness of 0.5 mm.     

Low-resistance standard measures of resistance

The construction and results of an investigation of lowresistance measures of electrical resistance (10 su–1), 1 ) for use in dc and ac circuits are described. The measures are used as standard measures of resistance and also as scale conveners in the State special and working standards of ac power.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 52–53, October, 1994.