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Estimation of Different Configuration of Demonstration Space Solar Power Station
Get PDFDevelopment of engineering of solar space power system involves as a first stage the launch of demonstration space solar power plant (SSPP) based on the current satellite platforms and launch vehicles. The type of general-arrangement diagram of space segment of SSPP will be the class of transformable structure of photo convertors with maximum surface area. In this manuscript is carrying out analysis of different versions of transformable structures of photo convertors in PROTON launch vehicle use. It is proved that such kind of version would allow successfully implement demonstration SSPP with reasonable power of transferable laser energy to the ground receiving point
γ-Radiolysis of Trioctyl Phosphine Oxide and Its Emulsification Phenomenon
Get PDFIn thisarticle, the γ-radiolysis of trioctyl phosphine oxide (TOPO) regarded as the typical representative of trialkyl phosphine oxide (TRPO) composites has been studied. The irradiated sample solutions were extracted with 5% Na2CO3 aqueous solution, then washed with triply distilled water. The emulsification phenomenon was foundduring thewashing process. The extent of emulsification was dependent on the absorbed dose and the pH value of the system. IR and UV spectroscopy as well as elemental analysis were used to determine the structures of the final products. The resultsindicated that the main scrubbed products werephosphinic acid, its ester and an oligomer of TOPO whichinduced emulsification and produced permanent damage on TOPO
Advances of Some Recent Mechanical Models on Emergency Evacuation
Get PDFSince the rapid development of the society, the living area of human beings has become much wider and more complicated. Over the past decades, crowd evacuation of public places has always been a hot topic in terms of public security studies. From the early twentieth century, emergency evacuation models have emerged, developing from statistic methods to mathematical models and recently, computer simulation models. In this paper, the classic mechanical models from the very beginning are reviewed. Utilizing the available literatures, we compare the nouveau models with the classic ones and highlight their advances. The key observation is that the consideration of individual and collective behaviours of the crowd and the appropriate scale of the model should have significant influences on the modeling performances. Finally, the Smoothed Particle Hydrodynamics models are introduced as a recent advance, which takes into consideration both the individual and collective behaviours of the crowd
Passivating Silicon Grain Boundaries with Small Polar Molecules for Photovoltaics
Get PDFGrain boundaries (GBs) play a major role in determining the device performance of in particular polycrystalline thin-film solar cells. Hydrogen has traditionally been applied to passivate defects at GBs. However, hydrogenated films are subject to light-induced degradation effects. In this study, we took a novel approach to passivating GBs in multicrystalline silicon (mc-Si) wafers with small polar molecules. We found an excellent correlation between the grain misorientation, electrical resistance across GBs, and passivation effectiveness. In particular, the charge transport across GBs was greatly enhanced after the wafers were properly treated in our polar molecule solutions; the sheet resistance can be reduced by up to more than one order for large-angle random GBs. The results were explained to be due to the effective charge neutralization and passivation of polar molecules on localized charge states at GBs. These findings may help us achieve high-quality materials at low cost for high-efficiency solar cells by enhancing carrier transport and minimizing carrier recombination
Nanocrystalline and Amorphous Silicon Semiconductors as Competing Candidates for PV Applications
Get PDFThe optical properties of two Hydrogenated nanocrystalline (nc-Si: H) and amorphous silicon (a-Si: H) thin film samples are investigated using conventional spectrophotometric technique. Both samples were prepared by plasma enhanced chemical vapor deposition technique (PECVD). The nc-Si: H sample prepared with 1% silicon concentration at temperature of 220˚C with ∼1 Å/s growth rate exhibits optical behavior closer to crystalline Silicon (c-Si) sample than the a-Si: H sample prepared with Helium (He) percentage of the initial gas mixture of 20 at temperature of 80˚C with increased growth rate of ∼2.8 Å/s. The optical constants, thicknesses and the energy band gap of both samples are obtained from the transmission data only. The values of refractive index within an estimated uncertainty of 1% for both a- Si: H and nc-Si: H samples are found close to those of c-Si sample in the chosen range of wavelengths. Both samples are found to have the same optical energy gap of ~1.7 eV within an uncertainty of ~ 0.03 eV and exhibit absorption features close to those of c-Si sample. The absorption behavior in the visible and near infrared regions of electromagnetic spectrum makes both samples good candidates for photovoltaic (PV) applications
Theoretical and Experimental Investigations on the Novel Involute-Helix Gear Drive
Get PDFThe theoretical and experimental investigations on involute-helix gear drive are carried out in this paper. Based on the generation principle and mathematical models, parametric design for tooth profiles is provided and three-dimensional solid models are established for simulation of motion. The general characteristics of involute-helix gears are discussed including undercutting condition, the separability of central distance, sliding and meshing characteristics. The meshing essence of tooth surfaces is revealed. Transmission efficiency experiment is made based on the developed gear prototype and the influence factors for the obtained results are also shown
Photovoltaic-Installation Performance in Central Europe on the Example of Poland
Get PDFThe amount of the electric energy obtained from a photovoltaic (PV) installation depends on the energy of the radiation. Weather conditions differ strongly between various years even in the same season. Depending on the climatic conditions of a given location, fixed PV solar plants as well as one-axis and dual-axis tracking PV solar plants are being installed worldwide. The aim of this work is to analyse the sunlight intensity and PV system performance under the geographic conditions of central Europe. The analysis was made on the basis of multi-month monitoring in Gdańsk, Poland, and by comparison with systems in other locations on the basis of the results of researchat Opole University, West Pomeranian University of Technology, Szczecin, Poznan University of Technology, and AGH University of Science and Technology.The annual irradiation and the electrical PV energy production have been averaged over a time period of several years. Two aspects are explored within this paper: the expected average annual electricity generation of a standard 1-kWp standalone or grid-connected PV system and the theoretical potential of PV electricity generation in the European countries
Potential for Energy Conservation by a Hybrid Natural Lighting System with LED Illumination
Get PDFIn buildings, efficient lighting systems and excellent design of interior natural light illumination would contribute to energy saving by direct use solar energy for illumination. This paper propose a model of hybrid natural lighting system with LEDs illumination that would be improve the efficiency of solar energy use. The system is compounded by a prismatic daylight collector, a reflector for re-directing daylight into the room and a diffuse reflector for indoor illumination. The main emerged intensity distribution of the right-angle prismatic collector was investigated using matrix ray tracing model and edge ray principle. The directionality of main emerged light from hypotenuse of the prism is applied to effort the performance of natural light illumination systems by simply guiding design. In this paper, we propose that an efficient hybrid natural lighting system with LED which combined with the prismatic daylight collector can be realizable by a suitable tilted angle of the prismatic daylight collector for different daylight conditions. The reduced electrical energy consumption for using hybrid natural lighting system with LED illumination system can contribute to 70%, 61% and 40% compared to using T8 fluorescent, T5 fluorescent and LEDs, respectively
An Algorithm for Determining Optimum Tilt Angle and Orientation for Solar Collectors
Get PDFProper installation, especially the tilt angle, directly affects the system’s output. Determination of the optimal tilt angle of a solar cell module depends on the solar radiation characteristics, season, and reflectivity in the local area. One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. A mathematical model is presented for determining the optimum tilt angle at different orientations (surface azimuth angle) for the solar collector, on a daily basis, as well as for a specific period such as monthly, seasonally and yearly basis. The optimum angle was computed by searching for the values for which the extraterrestrial solar radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle) or even 4 times/year (i.e. using the seasonally optimum tilt angle) maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 5.5% at 0o latitude to 78% at 60o latitude more than the case of a solar collector fixed on a horizontal surface
Strategy of Air Supremacy and Defense for a Quick End to Twenty- First Century Conflict – Research Required
Get PDFAir supremacy including land supremacy depends on equipment and weapons researched and developed with superior engineering knowledge, design and practice. There is the analytical and computational part, as well as the essential product realization portion. Superiority in engineering knowledge and practice is requisite. There are also telltale clues from the lyrics of national anthems, which may speak of a nation’s desire for military superiority, or at least of being undaunted by military conflict to maintain a nation’s independence. Airborne drones are being recognized as being essential for air supremacy in the twenty-first century, and are the focus of this article. The technology of airborne drones rests on the shoulders of aircraft technology, on robotics and computer technology, especially at the micro-scale end of fast and powerful computers. This work is focused on the research and development required to maintain/ acquire air supremacy in this twenty-first century, so that military conflicts need not drag on. Numerous lives can be spared as a consequence