Thermoelectric Converters of Human Warmth for Self-Powered Wireless Sensor Nodes

Solar cells are the most commonly used devices in customer products to achieve power autonomy. This paper discusses a complementary approach to provide power autonomy to devices on a human body, i.e., thermoelectric conversion of human heat. In indoor applications, thermoelectric converters on the skin can provide more power per square centimeter than solar cells, particularly in adverse illumination conditions. Moreover, they work day and night. The first sensor nodes powered by human heat have been demonstrated and tested on people in 2004-2005. They used the state-of-the-art 100-muW watch-size thermoelectric wrist generators fabricated at IMEC and based on custom-design small-size BiTe thermopiles. The sensor node is completed with a power conditioning module, a microcontroller, and a wireless transceiver mounted on a watchstrap     

The spatial scales of heterogeneities in the direct-current discharge stream

The results of a calculational-experimental investigation of spatial scale heterogeneities in a gas stream with direct-current discharge are presented. The numerical modeling was made within the framework of the Navier-Stokes equations with a distributed source of input energy density in a gas. The experimental study was conducted by the Talbot-interferometry method. The Shtrel number was used as the criterion of the optical homogeneity of the stream.St. Petersburg Institute of Mechanics. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 62, No. 6, pp. 820–824, June, 1992.     

Simulation of Signals Transmitted in a Multichannel Information Speed System and Experimental Check of the Results

Characteristics of pulse signals transmitted in a multichannel information speed system widely used in physical setups of the State Research Center Institute of High-Energy Physics on a 70-GeV accelerator are studied. The simulation is carried out for various configurations of the system, taking into account special design features of the modules. The characteristics of the pulses and values of correcting (damping) components are determined, and the calculated and experimental results are compared.     

Therapeutic Effects of hiPSC-Derived Glial and Neuronal Progenitor Cells-Conditioned Medium in Experimental Ischemic Stroke in Rats

Transplantation of various types of stem cells as a possible therapy for stroke has been tested for years, and the results are promising. Recent investigations have shown that the administration of the conditioned media obtained after stem cell cultivation can also be effective in the therapy of the central nervous system pathology (hypothesis of their paracrine action). The aim of this study was to evaluate the therapeutic effects of the conditioned medium of hiPSC-derived glial and neuronal progenitor cells in the rat middle cerebral artery occlusion model of the ischemic stroke. Secretory activity of the cultured neuronal and glial progenitor cells was evaluated by proteomic and immunosorbent-based approaches. Therapeutic effects were assessed by overall survival, neurologic deficit and infarct volume dynamics, as well as by the end-point values of the apoptosis- and inflammation-related gene expression levels, the extent of microglia/macrophage infiltration and the numbers of formed blood vessels in the affected area of the brain. As a result, 31% of the protein species discovered in glial progenitor cells-conditioned medium and 45% in neuronal progenitor cells-conditioned medium were cell type specific. The glial progenitor cell-conditioned media showed a higher content of neurotrophins (BDNF, GDNF, CNTF and NGF). We showed that intra-arterial administration of glial progenitor cells-conditioned medium promoted a faster decrease in neurological deficit compared to the control group, reduced microglia/macrophage infiltration, reduced expression of pro-apoptotic gene Bax and pro-inflammatory cytokine gene Tnf, increased expression of anti-inflammatory cytokine genes (Il4, Il10, Il13) and promoted the formation of blood vessels within the damaged area. None of these effects were exerted by the neuronal progenitor cell-conditioned media. The results indicate pronounced cytoprotective, anti-inflammatory and angiogenic properties of soluble factors secreted by glial progenitor cells.     

Design and fabrication of a 24-channel acousto-optic spatial light modulator

Acousto-optic (AO) devices are important spatial light modulators. They can be used as light-beam deflectors, rf true-time-delay lines, etc. To increase their spur-free dynamic range, we present what to our knowledge is a novel multichannel AO device structure, in which different channels have different carrier frequencies, so a wideband signal can automatically be decomposed into a set of narrow-band signals. Design, fabrication, and testing of this 24-channel, 10-mus AO spatial light modulator are addressed.     

Methods for suppressing nonlinear oscillations in astatic auto-piloted aircraft control systems

Journal of Computer and Systems Sciences International - This review is devoted to the control problem with constraints on the magnitude and rate of change of the control action in aircraft control...     

A mechanical model of fatigue crack propagation. Report 2

Conclusions The proposed model of fatigue crack propagation based on the solution of the cyclic elastoplastic problem of the stress-strain state [1] makes it possible to take into account the effect of the triaxial stress state on the deformation of the material at the crack tip. The proposed algorithm of calculations of the state of damage on the basis of the principle of linear damage summation and also the agreement between the calculated and experimental data confirm the assumption on the controlling role of low-cycle damage in the mechanics of crack propagation in cyclic loading described from phenomenological positions. The main advantages of the proposed model are:The possibilities of calculating endurance in crack propagation or calculating the crack propagation rate for cases in which the variation of the range of the stress intensity factor along the crack length in structural members takes place at a variable loading asymmetry;the possibilities of describing the effect of loading asymmetry on the fatigue crack-propagation rate using only the strain criterion (Coffin's equation) since the range of the plastic strain intensity at the crack tip is, as shown in [1], a function of not only the range of the stress intensity factor K but also of its maximum value K_max;the possibilities of describing the dependence of K_th on loading asymmetry based on the assumption on the constancy of the size of the structural element for the given material;the possibilities of describing the crack propagation rate in all the three sections of the dL/dN=f(K) diagram, starting with the values K similar to K_th and ending with the value of K at which monotonic quasistatic fracture becomes the controlling process.Translated from Problemy Prochnosti, No. 8, pp. 14–18, August, 1985.     

Use of powdered coal in the cold charge during electrical steelmaking

Ukrainian Scientific Research Institute of Special Steels (UkrNIIspetsstal') and the Krasnyi Oktyabr Plant. Translated from Metallurg, No. 2, p. 36, February, 1991.