Photovoltaic Power Supply Unit for the Basic Stations of Cellular Companies

The data on the use of solar photovoltaic plants (PVPs) for providing a reliable and guaranteed power supply to telecommunication systems and cellular communication systems in the conditions prevalent in Uzbekistan are given. The research-based structures developed by OOO MIR SOLAR and the selection of PVP elements ensuring their reliable operation are described. The main influencing factors are discussed, and the use of effective combinations of different types of panels (from monocrystalline and polycrystalline silicon) and a specially developed controller are considered.     

Bioenergy,food security and poverty reduction: trade-offs and synergies along the water–energy–food security nexus

This article provides a review of trade-offs and synergies of bioenergy within the water–energy–food security nexus, with emphasis on developing countries. It explores the links of bioenergy with food security, poverty reduction, environmental sustainability, health, and gender equity. It concludes that applying the nexus perspective to analyses of bioenergy widens the scope for achieving multiple-win outcomes along the above aspects.     

Investigation of parameters of photothermoconverter based on Si solar cells

A photothermoconverting unit based on thin (180 μm) high-efficiency solar cells manufactured by Sunoasis (the People’s Republic of China) has been developed, and its parameters have been investigated under the full-scale conditions of Tashkent. The output photovoltaic parameters of this photothermoconverting system have been studied under different temperatures; the temperature coefficients DUnl/DT and Dh/DT of the solar cells in a solar array are determined. The differences in the values of the temperature coefficients for the isolated solar cells and for those in a solar array are analyzed. A method to experimentally determine the “overheating” temperature of the solar cell incorporated in a solar array is proposed. The recommendations for further investigations are developed.     

Calculation of the temperature of the internal surface of the heat-removing channel wall of the ray-absorbing heat-exchange panels of flat-plate solar water-heating collectors

The results of numerical research on the determination of the temperature value of the internal surface of the heat-removing channel (HRC) walls of the light-absorbing heat-exchange panels (LAHPs) with the tubeon- sheet and thin-parallelepiped form of flat-plate solar water-heating collectors (FPSWHCs) are presented. The research method is based on compilation of the system of the balance equations for the light-absorbing plate (LAP) and HRCs of the LAHPs of the studied types and their designs with respect to the desired parameter. A practical example of calculation of the determination of the temperature value of the internal surface of the HRC wall of the tube-on-sheet LAHP, where the results of experimental research on the determination of the specific thermal efficiency of the mean-quality FPSWHC in full-scale terms, as well as laboratory and numerical research on determination of the optical and thermotechnical indicators of the copper tube-on-sheet LAHP.     

Photoelectric device for street lighting based on silicon solar cells

The paper considers the negative influence of “overheating” of monocrystalline silicon solar cells in the composition of solar batteries on the output characteristics of photoelectric installations. The construction is described of a photoelectric street lighting installation in which this influence is taken into account. The results of tests under natural conditions are presented.     

Development dynamics of OOO Mir Solar

The results of OOO Mir Solar activities for the development and implementation of off-grid solar photovoltaic power plants in Uzbekistan are considered.     

Photothermal converters with silicon solar cells

Results are presented of a study of the possibility for creating a photothermal converter (PTC) and its parameters in the actual conditions of Tashkent. We study the photoelectric output parameters of the PTC to determine the potential capabilities for supplying the electric power for the household and utility appliances and also hot water for the individual energy consumers that are located in the regions that are far from the centralized power sources.     

Microwave Study of Influence of Trapped Vortices on Intergrain Weak Links in Eu-123 Ceramics

The well known low field signal observed in high temperature superconducting (HTS) ceramics by an ESR spectrometer was used for studying the vortex structure of remanent fields in 123-ceramics. The drastically different behaviors have been observed for the orientations of an external magnetic field either parallel or perpendicular to thin platelet sample. It is shown that our experimental results can be explained by influence of trapped Abrikosov and Josephson-type vortices on critical currents of intergrain weak links.     

SUSIG: an on-line signature database, associated protocols and benchmark results

We present a new online signature database (SUSIG). The database consists of two parts that are collected using different pressure-sensitive tablets (one with and the other without an LCD display). A total of 100 people contributed to each part, resulting in a database of more than 3,000 genuine signatures and 2,000 skilled forgeries. The genuine signatures in the database are real signatures of the contributors. In collecting skilled forgeries, forgers were shown the signing process on the monitor and were given a chance to practice. Furthermore, for a subset of the forgeries (highly skilled forgeries), this animation was mapped onto the LCD screen of the tablet so that the forgers could trace over the mapped signature. Forgers in this group were also informed of how close they were to the reference signature, so that they could improve their forgery quality. We describe the signature acquisition process and several verification protocols for this database. We also report the performance of a state-of-the-art signature verification system using the associated protocols. The results show that the highly skilled forgery set is significantly more difficult compared to the skilled forgery set, providing researchers with challenging forgeries. The database is available through .     

Investigations of the energetic and thermal characteristics of a module based on a Fresnel lens and a hetero-photo-converter in the AlGaAs-GaAs system

The energetic and thermal characteristics of a photobattery module based on a Fresnel lens and a hetero-photo-converter (HPC) in the AlGaAs-GaAs system are investigated. One has been shown experimentally an influence of volumetric irregularities regarding resistance of heterostructures formed up in active areas due to the diffusion of Zn atoms on p-n-junction boundaries under liquid-phase epitaxy on the photoconverter loading characteristics at low illumination levels. A substantial influence of the spread resistance on the HPC optimal parameters at elevated illuminations has been shown. For the regime chosen, the temperature of the cells reaches up to 80°C, and, at that temperature, it has no influence on the contacts’ properties and the space factor of the converter’s voltage-current characteristics (VCC). The module generates power up to 650 mW without forced cooling and allows combining it with a solar-heat collector.