Influence of microgravity on mitogen binding and cytoskeleton in Jurkat cells.

The effects of microgravity on Jurkat cells--a T-lymphoid cell line--was studied on a sounding rocket flight. An automated pre-programmed instrument permitted the injection of fluorescent labelled concanavalin A (Con A), culture medium and/or fixative at given times. An in-flight 1 g centrifuge allowed the comparison of the data obtained in microgravity with a 1 g control having the same history related to launch and re-entry. After flight, the cells fixed either at the onset of microgravity or after a or 12 minute incubation time with fluorescent concanavalin A were labelled for vimentin and actin and analysed by fluorescence microscopy. Binding of Con A to Jurkat cells is not influenced by microgravity, whereas patching of the Con A receptors is significantly lower. A significant higher number of cells show changes in the structure of vimentin in microgravity. Most evident is the appearance of large bundles, significantly increased in the microgravity samples. No changes are found in the structure of actin and in the colocalisation of actin on the inner side of the cell membrane with the Con A receptors after binding of the mitogen.     

Enhancing Maintainability of the AWG-10 Through Built-In-Test Equipment

Multimode airborne weapons systems are now a reality. Because of the increased complexity of these systems, excessive maintenance time has become a problem. This paper describes an approach to reducing maintenance time through the use of semiautomatic built-in-test equipment within the framework of an integrated maintenance program. Emphasis is placed on the methods and hardware involved in the built-in-test mechanization as well as describing the development history of this type of maintenance concept.     

Design of Zigzag FM Signals

Since no practical method is available for synthesizing radar waveforms, a sizable effort has been directed into studies of the matched-filter response, or ambiguity function, of many waveforms. In this paper, we investigate the class of FM signals whose instantaneous frequency varies in a zigzag pattern. The waveforms thus consist of linear FM segments and are relatively easy to generate and process. The paper discusses the relation between the characteristics of the waveform and the features of the associated ambiguity function. The effects studied include those of signal repetition, changes in the FM slope, phase-shift and frequency-shift coding, and staggering of frequency step and segment duration. Ambiguity functions of interesting waveforms illustrate the general results. These ambiguity functions are computer-plotted projections of the three-dimensional surface above the delay-Doppler plane.     

Statistical study of interplanetary condition effect on geomagnetic storms: 2. Variations of parameters

We investigate the behavior of mean values of the solar wind’s and interplanetary magnetic field’s (IMF) parameters and their absolute and relative variations during the magnetic storms generated by various types of the solar wind. In this paper, which is a continuation of paper [1], we, on the basis of the OMNI data archive for the period of 1976–2000, have analyzed 798 geomagnetic storms with D _st ≤ −50 nT and their interplanetary sources: corotating interaction regions CIR, compression regions Sheath before the interplanetary CMEs; magnetic clouds MC; “Pistons” Ejecta, and an uncertain type of a source. For the analysis the double superposed epoch analysis method was used, in which the instants of the magnetic storm onset and the minimum of the D _st index were taken as reference times. It is shown that the set of interplanetary sources of magnetic storms can be sub-divided into two basic groups according to their slowly and fast varying characteristics: (1) ICME (MC and Ejecta) and (2) CIR and Sheath. The mean values, the absolute and relative variations in MC and Ejecta for all parameters appeared to be either mean or lower than the mean value (the mean values of the electric field E _y and of the B _z component of IMF are higher in absolute value), while in CIR and Sheath they are higher than the mean value. High values of the relative density variation sN/〈N〉 are observed in MC. At the same time, the high values for relative variations of the velocity, B _z component, and IMF magnitude are observed in Sheath and CIR. No noticeable distinctions in the relationships between considered parameters for moderate and strong magnetic storms were observed.     

Structural health management technologies for inflatable/deployable structures: Integrating sensing and self-healing

Inflatable/deployable structures are under consideration as habitats for future Lunar surface science operations. The use of non-traditional structural materials combined with the need to maintain a safe working environment for extended periods in a harsh environment has led to the consideration of an integrated structural health management system for future habitats, to ensure their integrity. This article describes recent efforts to develop prototype sensing technologies and new self-healing materials that address the unique requirements of habitats comprised mainly of soft goods. A new approach to detecting impact damage is discussed, using addressable flexible capacitive sensing elements and thin film electronics in a matrixed array. Also, the use of passive wireless sensor tags for distributed sensing is discussed, wherein the need for on-board power through batteries or hardwired interconnects is eliminated. Finally, the development of a novel, microencapuslated self-healing elastomer with applications for inflatable/deployable habitats is reviewed.     

Thermodynamic properties of mixed fuel combustion products

In this paper, the results of calculating the processes of two fuel mixture combustion in different proportions are presented. The values of temperature, thermal capacity, specific gas constant and isentropic expansion ratio of combustion products are given. Also shown is the distinction of thermodynamic properties from the additivity law.     

Analysis of nonlinear deformation and stability of reinforced elliptic cylindrical shells under bending with internal pressure

A finite element statement of solving problems on stability of reinforced elliptic cylindrical shells taking into account momentness and nonlinearity of their subcritical stress strain state is presented. The explicit expressions for displacements of noncircular cylindrical shell elements as rigid bodies are determined by integrating the equations obtained by equating the components of linear strains to zero. These expressions were used to construct the form functions for an efficient quadrilateral finite element of natural curvature. An efficient numerical algorithm of nonlinear deformation and stability of shells was developed. The stability of reinforced elliptic cylindrical shells under combined loading by bending moment, transverse boundary force and internal pressure is analyzed. We also examine how the critical loads are affected by the strain nonlinearity and ellipticity of shell deformation at the subcritical stage.     

Analysis of shells of revolution under axisymmetrical loading using the quadrature method

To complete study [1], the procedure of applying the numerical quadrature method to analyzing the shells of revolution under axisymmetrical loading is presented.     

Improvement of conventional combustion chamber structure in order to enhance GTE ecological indicators

The test results of a conventional combustion chamber with the improved structure are presented. The concentration of toxic substance emissions is reduced as compared with combustion chambers of the similar type.