On the conditions of gas inclusions formation in melts under zero gravity state (after “Pirin” experiment)

Thermodynamics relations have been considered under which gas inclusions may form in melts (closed systems), due to both volatility of components and the presence of dissolved gases. It has been shown that in the melts with sufficient volatility of components, gas inclusions may form under equilibrium conditions if the ampoule is wetted well by the melt, whereas in case of low wettability they form under non-equilibrium state only. The foaming in the tellurium-selenium system has been analysed (“Pirin”, KP-4 experiment).In the melts containing dissolved gases, gas inclusions form under conditions of deviation from equilibrium and it is the main mechanism of outgassing. It has been demonstrated that the melt foaming method using hydrid compounds may be applied to the materials exhibiting a hysteresis of temperature dependence of diluted hydrogen concentration. Production of foam aluminium under zero gravity state has been considered as an example (“Pirin”, SP-3 experiment).     

Marangoni convection in a liquid layer under the simultaneous action of a transverse magnetic field and rotation

Asymptotic stability characteristics with respect to the onset of Marangoni convection in a liquid layer under the simultaneous action of a large transverse magnetic field and a large rate of rotation are investigated. In certain parameter ranges there is a decrease in critical Marangoni number for increasing magnetic field and rotation depending on the coupling between interfacial perturbations and rotation.     

Earth benefits from space life sciences

Contributions of space exploration which are widely recognized are those dealing with the impact of space technology on public health and medical services in both urban and remote rural areas. Telecommunications, image enhancement, 3-dimensional image reconstructions, miniaturization, automation, and data analysis, have transformed the delivery of medical care and have brought about a new impetus to the field of biomedicine. Many areas of medical care and biological research have been affected. These include technological breakthroughs in such areas as: (1) diagnosis, treatment, and prevention of cardiovascular diseases, (2) new approaches to the understanding of osteoporosis, (3) early detection of genetic birth defects, (4) emergency medical care, and (5) treatment of chronic metabolic disorders. These are but a few examples where technology originally developed to support space medicine or space research has been applied to solving medical and health care delivery problems on Earth.     

IR-spectroscopy of ionosphere from stratospheric balloons

The radiation spectra of the ionosphere in the 4–5 μm region have been determined from stratospheric balloons by means of the specially elaborated method of the registration of angular and spectral distribution of the radiation. The radiation bands of 4.4 μm and 4.8 μm which have 0.1–0.2 erg cm^?2 sr^?1s^?1. brightness obtained in two flights, are identified with the vibration-rotation transitions of the ion NO⁺ (0 - 1) and the molecules N¹⁴N¹⁵ (0 - 1) and CO (0 - 1) and (3 - 2) from altitudes between 120 and 500 km.     

50–200 GV cosmic rays at various heliolatitudes

We consider regular motion of 50 – 200 GV particles in a large-scale interplanetary magnetic field model which contains a wavy neutral sheet responsible for the sector-structure. Numerical calculations based upon energy losses along various trajectories are carried out to obtain the predicted omni-directional density and anisotropy of cosmic rays at various solar latitudes. A marked difference is found between odd and even solar cycles. The post-1969 field configuration gives small radial and large latitudinal gradient: cosmic ray density increases toward the poles. The latitudinal gradient turns out smaller and of opposite sense for the pre-1969 epoch. Anisotropy changes dramatically as we move off the solar equator: corotation appears to be restricted to low latitudes.     

Vertical profiles of halocarbons in the stratosphere

Stratospheric air samples collected between 10 and 35 km altitude my means of a cryogenic sampler were analyzed by gaschromatography. Thus vertical profiles of source gases for halogen radicals were derived, such as CCl₄, CCl₃F, CCl₂F₂, CClF₃, CF₄, C₂F₃Cl₃, C₂F₄Cl₂, C₂F₅Cl, C₂F₆, CH₃Cl, CH₃CCl₃, CHF₂Cl, CH₃Br, CBrF₃, and CBrCl₂F. Systematic discrepancies between measured and modelled halocarbon profiles point to deficiencies of present one- and two-dimensional models. Measurements of fully halogenated hydrocarbons provide a tool for systematically studying these deficiencies and thus improving the models.     

Simulation of Permanent Magnet Generator/Rectifier Combination

Permanent magnet generators are often used as the pilot exciters of three-stage generating units to provide an efficient and reliable source of electrical power. No external power supply is then necessary, and the problems associated with brushwear and with arcing at the rubbing contacts are eliminated. A technique is presented here by which the performance of a permanent magnet generator, when combined with a rectifier-fed d.c. load at its output terminals, may be accurately and efficiently computed. The machine model takes into account the magnetization characteristic of the permanent magnet rotor and involves only parameters which can be determined from terminal measurements on the machine at standstill. Both computed and measured characteristics for an experimental machine are presented, and a comparison of these characteristics shows that the model can predict accurately all the major characteristics of the machine, as well as its detailed internal performance, when supplying a typical resistiveinductive load.     

Application of remote sensing techniques in mineral resources survey — a case study pertaining to Singhbhum Shear Zone,Bihar, India

Geological analysis and evaluation of digitally processed and enhanced LANDSAT MSS data products for three test areas of Singhbhum Shear Zone, India has led to certain significant results regarding optimisation and utility of such techniques for geological studies and obtaining additional/new information regarding lithology and structure. Three band-to-band ratio images are found to give best results. Lithologic formations could be subdivided into a number of units. The Westward and southeastward extension of the shear zone could be delineated thereby indicating scope of mineralisation in these parts.     

Droplet vaporization in supercritical pressure environments

For most liquid-fueled combustion systems the behavior of the fuel as it is introduced to the combustion zone, often by spray injection, will have a significant impact on combustion. The subsequent combustion may be affected to a considerable degree by the initial spread of the liquid, break-up of larger fuel sheets and droplets into droplets of various sizes, droplet vaporization, and diffusion of gaseous fuel. Among the many factors which affect spray break-up and droplet vaporization are the environmental conditions into which the spray is introduced. For both diesel engines and rockets the environment pressure and temperature may be above the critical pressure and temperature of the injected fuel. In a compression-ignition internal combustion engine, the environment consists primarily of air, at pressures from 20 to 100 atmospheres and temperatures ranging from 900 to 1500 K. Even higher pressures are encountered in turbocharged diesels. A typical diesel reference fuel, dodecane, has a thermodynamic critical pressure of about 17 atmospheres, and a critical temperature of 600 K. Fuel is injected into a diesel engine environment in which ambient pressures exceed the critical pressure. While droplet temperatures are subcritical at first, they may rise to the critical temperature or higher.This paper will survey current understanding of supercritical pressure droplet vaporization. Specifically, the topics covered will include: liquid phase behavior; vapor phase behavior; thermodynamic and transport properties; droplet distribution and break-up; micro-explosions; and effects of microgravity.