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Search Results: 1 - 10 of 19738 matches for " Alexander Pogrebnoi "
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Theoretical Design of Complex Molecule via Combination of Natural Lawsone and Synthetic Indoline D131 Dyes for Dye Sensitized Solar Cells Application  [PDF]
Nyanda Madili, Alexander Pogrebnoi, Tatiana Pogrebnaya
Computational Chemistry (CC) , 2018, DOI: 10.4236/cc.2018.64007
The dye sensitized solar cells (DSSCs) have been extensively studied due to their low production cost and simple fabrication process. Dye co-sensitization broadens the absorption spectrum of the sensitizer; thus enhances light harvesting efficiency; and contributes to the improvement of the DSSCs overall efficiency. In this study we performed theoretical design of complex molecule (C45H32N2O4) through combination (esterification reaction) of the natural dye lawsone and synthetic metal free indoline dye D131. The excitation energies, vibration spectra, molecular structures, electronic absorption spectra and electron transitions in individual dyes and complex molecule were investigated using density functional theory (DFT) and time dependent density functional theory (TD-DFT) B3LYP5 methods, with 3-21G, 6-31G and 6-31G(d,p) basis sets. The UV-Vis absorption spectra of the individual dyes and their mixture in chloroform solution were measured using spectrophotometer. For the complex formation reaction, enthalpy, entropy and Gibbs free energy were calculated and the results indicated the reaction was endothermic and non-spontaneous. Electron density distribution of the frontier and adjacent molecular orbitals and energy levels alignment were used for analysis of the electronic spectra and mechanism of transitions. The results indicated that the designed complex molecule satisfied the requirements for good photosensitizer of DSSCs.
Theoretical Study of the Interaction between Chitosan Constituents (Glucosamine and Acetylglucosamine Dimers) and Na Ions  [PDF]
Marwa Emmanuel, Alexander Pogrebnoi, Tatiana Pogrebnaya
Open Access Library Journal (OALib Journal) , 2015, DOI: 10.4236/oalib.1101978
Abstract: The interaction of dimers of glucosamine and acetylglucosamine molecules with sodium ion has been studied using the DFT/B3LYP approach. The optimization of geometrical parameters and vibrational spectra calculations were done under 6-31G(d) basis set, and energies of the reactions were obtained using 6-311 G(d, p) basis set. The enthalpies of the association reactions of the dimers of glucosamine and acetylglucosamine with Na have been determined. The internal hydrogen bonds OH…O and NH…O have been shown to play an important role in conformational behavior of a particular molecule.
Oldoinyo Lengai Volcanic Ash for Removal of Hydrogen Sulfide and Ammonia from Biogas  [PDF]
Isack Kandola, Alexander Pogrebnoi, Tatiana Pogrebnaya
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.64010
Abstract: Oldoinyo Lengai mountain located in Northern Tanzania is the only active natrocarbonatite volcano with unusually alkali-rich natrocarbonatites which are not found elsewhere in the world. Volcanic ash formed earlier during eruptions was collected from different sites along the mountain, and its potency to adsorb hydrogen sulfide (H2S) and ammonia (NH3) from biogas was investigated. The samples were calcinated at different temperatures (550 - 850) and were characterized by X-ray florescent, scanning electron microscopy and X-ray diffraction techniques. The on-site adsorption experiments were conducted at the biogas digester at ambient conditions. The calcinated ash was packed into the reactor bed, biogas allowed to pass through the adsorbent, and the inlet and outlet concentrations of H2S and NH3 were measured. The height of the site where the adsorbent was taken from, calcination temperature, biogas flowrate and mass of the adsorbent were variable parameters and found to influence greatly on the efficiency of H2S and NH3 removal. The efficiency is increased with calcination temperature raise and mass of adsorbent and decreased with flowrate increase. The samples collected from the top site of the mountain and calcinated at 850℃ exhibited the best sorption performance.
Facile and Convenient One-Pot Process for the Synthesis of Spirooxindole Derivatives in High Optical Purity Using (?)-(S)-Brevicolline as an Organocatalyst
Fliur Macaev,Natalia Sucman,Felix Shepeli,Marina Zveaghintseva,Vsevolod Pogrebnoi
Symmetry , 2011, DOI: 10.3390/sym3020165
Abstract: The paper presents an application of the asymmetry approach to spirooxindoles via Brevicolline, Cinchonidine or Cinchonine catalyzed one-pot multicomponent synthesis. Brevicolline, in comparison with Cinchonidine or Cinchonine, catalyzes the reaction of isatins, acetylacetone/ethyl 3-oxobutanoate and malononitrile, with the formation of spiro[oxindole-3,4'-4'H-pirane] derivatives in an optically active form in very good to excellent yields.
Protection of Environment from Damaged Nuclear Station and Transparent Inflatable Blanket for Cities—Protection from Radioactive Dust and Chemical, Biological Weapons  [PDF]
Alexander Bolonkin
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.24037
Abstract: The author, in a series of previous articles, designed the “AB Dome” made of transparent thin film supported by a small additional air overpressure for the purpose of covering a city or other important large installations or sub-regions. In present article the author offers a variation in which a damaged nuclear station can be quickly covered by such a cheap inflatable dome. By containing the radioactive dust from the damaged nuclear station, the danger zone is reduced to about 2 km2 rather than large regions which requires the resettlement of huge masses of people and which stops indus-try in large areas. If there is a big city (as Tokyo) near the nuclear disaster or there is already a dangerous amount of radioactive dust near a city, the city may also be covered by a large inflatable transparent Dome. The building of a gi-gantic inflatable AB Dome over an empty flat surface is not difficult. The cover is spread on a flat surface and a venti-lator (fan system) pumps air under the film cover and lifts the new dome into place but inflation takes many hours. However, to cover a city, garden, forest or other obstacle course in contrast to an empty, mowed field, the thin film cannot be easily deployed over building or trees without risking damage to it by snagging and other complications. This article proposes a new method which solves this problem. The design is a double film blanket filled by light gas such as, methane, hydrogen, or helium - although of these, methane will be the most practical and least likely to leak. Sections of this AB Blanket are lighter than air and will rise in the atmosphere. They can be made on a flat area serving as an as-sembly area and delivered by dirigible or helicopter to station at altitude over the city. Here they connect to the already assembled AB Blanket subassemblies, cover the city in an AB Dome and protect it from bad weather, chemical, bio-logical and radioactive fallout or particulates. After assembly of the dome is completed, the light gas can be replaced by (heavier but cheaper) air. Two projects for Tokyo (Japan) and Moscow (Russia) are used in this paper for sample computation.
Filters and Ultrafilters as Approximate Solutions in the Attainability Problems with Constraints of Asymptotic Character  [PDF]
Alexander Chentsov
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.29062
Abstract: Abstract problems about attainability in topological spaces are considered. Some nonsequential version of the Warga approximate solutions is investigated: we use filters and ultrafilters of measurable spaces. Attrac- tion sets are constructed. AMS (MOS) subject classification. 46A, 49 K 40.
Using of High Altitude Wind Energy  [PDF]
Alexander Bolonkin
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.22010
Abstract: Ground based, wind energy extraction systems have reached their maximum capability. The limitations of current de-signs are: wind instability, high cost of installations, and small power output of a single unit. The wind energy industry needs of revolutionary ideas to increase the capabilities of wind installations. This article suggests a revolutionary innovation which produces a dramatic increase in power per unit and is independent of prevailing weather and at a lower cost per unit of energy extracted. The main innovation consists of large free-flying air rotors positioned at high altitude for power and air stream stability, and an energy cable transmission system between the air rotor and a ground based electric generator. The air rotor system flies at high altitude up to 14 km. A stability and control is provided and systems enable the changing of altitude. This article includes six examples having a high unit power output (up to 100 MW). The proposed examples provide the following main advantages: 1) Large power production capacity per unit—up to 5,000 - 10,000 times more than conventional ground-based rotor designs; 2) The rotor operates at high altitude of 1 - 14 km, where the wind flow is strong and steady; 3) Installation cost per unit energy is low; 4) The installation is environmentally friendly (no propeller noise).
Production of Freshwater and Energy from Earth’s Atmosphere  [PDF]
Alexander Bolonkin
Smart Grid and Renewable Energy (SGRE) , 2011, DOI: 10.4236/sgre.2011.22011
Abstract: The author offers a new, cheap method for the extraction of freshwater from the Earth’s atmosphere. The suggested method is fundamentally dictinct from all existing methods that extract freshwater from air. All other industrial methods extract water from a saline water source (in most cases from seawater). This new method may be used at any point in the Earth except the Polar Zones. It does not require long-distance freshwater transportation. If seawater is not utilized for increasing its productivity, this inexpensive new method is very environmentally-friendly. The author’s method has two working versions: 1) In the first variant warm (or hot) atmospheric air is lifted by the inflatable tube in a high altitude and atmospheric water vapor is condensed into freshwater: 2) in the second version, the warm air is pumped 20-30 meters under the sea-surface. In the first version, wind and solar heating of air are used for causing air flow. In version 2) wind and fans are used for causing air movment. The first method does not need energy, the second needs a small amount. Moreover, in variant 1) the freshwater has a high pressure (> 30 or more atm) and can be used for production of energy such as electricity and in that way the freshwater cost is lower. For increasing the productivity the seawater is injected into air and a solar air heater may be used. The solar air heater produces a huge amount of electricity as a very powerful electrical generation plant. The offered electricity installation is 100 - 200 times cheaper than any common electric plant of equivalent output.
Radial Electric Field in Tokamak Plasmas as a Physical Consequence of Ehrenfest’s Paradox  [PDF]
Romannikov Alexander
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.330201
Abstract: A simplified form and some possible theoretical resolutions of the so-called Ehrenfest’s Paradox are described. A relation between physical consequences of this relativistic paradox and charge density ρ of tokamak plasma is shown. Plasma experiments which could resolve the Ehrenfest’s Paradox are presented.
Ageing related events at nuclear power plants  [PDF]
Alexander Duchac
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.51005
Abstract: This paper presents main results of a comprehensive study performed by the European Clearinghouse on Operating Experience Feedback of NPP with the support of IRSN (Institut de S?reté Nucléaire et de Radioprotection) and GRS (Gesellschaft für Anlagen und Reaktorsi-cherheit mbH). Physical ageing mechanisms of structure, systems and components that eventually lead to ageing related systems and components failures at nuclear power plants were the main focus of this study. The analysis of ageing related events involved operating experience reported by NPP operators in France, Germany, USA and to the IAEA/NEA International Reporting system, on operating experience for the past 20 years (i.e. 1990-2009). A list of ageing related events was populated. Each ageing related event contained in the list was analyzed and results of analysis were summarized for each commodity group for which the ageing degradation appeared to be a dominant contributor or direct cause. The most common degradation mechanisms/ageing effects for each specific component/commodity group, their risk significance and consequences to the plant performance are described. This paper provides insights into ageing related operating experience as well as recommendations to deal with the physical ageing of nuclear power plant SSC important to safety.
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