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Characteristic Time of Diffusive Mixing in Cube with Reflecting Edges
Issue:
Volume 6, Issue 5, September 2017
Pages:
81-87
Received:
30 June 2017
Accepted:
11 July 2017
Published:
31 July 2017
Abstract: V. V. Uchaikin suggested a mathematical model of an anomalous diffusion in a space. These model origins in an investigation of processes in complex systems with variable structure: glasses, liquid crystals, biopolymers, proteins and a turbulence in a plasma. Here a coordinate of diffusing particle has stable distribution and so its density satisfies diffusion equation with partial derivatives. In this paper, the anomalous diffusion with periodic initial conditions on an interval with reflecting edges, important for example in technical mechanics, is considered and analyzed.
Abstract: V. V. Uchaikin suggested a mathematical model of an anomalous diffusion in a space. These model origins in an investigation of processes in complex systems with variable structure: glasses, liquid crystals, biopolymers, proteins and a turbulence in a plasma. Here a coordinate of diffusing particle has stable distribution and so its density satisfie...
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Comment on Half-Integer Quantum Numbers for the Total Angular Momentum of Photons in Light Beams with Finite Lateral Extensions
Issue:
Volume 6, Issue 5, September 2017
Pages:
88-90
Received:
5 July 2017
Accepted:
20 July 2017
Published:
15 August 2017
Abstract: Recently the spectacular result was derived quantum mechanically that the total angular momentum of photons in light beams with finite lateral extensions can have half-integer quantum numbers. In a circularly polarized Gauss light beam it is half of the spin angular momentum which it would have in a respective infinitely extended wave. In another paper it was shown by a classical calculation that the magnetic moment induced by such a beam in a metal is a factor of two smaller than the one induced by a respective infinitely extended wave. Since the system's angular momentum is proportional to its magnetic moment it could be assumed that the classical result for the magnetic moment reflects the transfer of the total angular momenta of the beam photons to the metal. Here we show that there is no hint that this is indeed the case.
Abstract: Recently the spectacular result was derived quantum mechanically that the total angular momentum of photons in light beams with finite lateral extensions can have half-integer quantum numbers. In a circularly polarized Gauss light beam it is half of the spin angular momentum which it would have in a respective infinitely extended wave. In another p...
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Bifurcation of Sound Waves in a Disturbed Fluid
Issue:
Volume 6, Issue 5, September 2017
Pages:
91-95
Received:
12 July 2017
Accepted:
19 July 2017
Published:
15 August 2017
Abstract: An equation that describes the wave propagation in the disturbed medium was deduced from the Lighthill’s equation. The so-called perturbation-cumulative approximation was suggested to solve this equation and the period-doubling bifurcation solutions were given. The results obtained in this paper helps to provide insights to the mechanism of the turbulence formation.
Abstract: An equation that describes the wave propagation in the disturbed medium was deduced from the Lighthill’s equation. The so-called perturbation-cumulative approximation was suggested to solve this equation and the period-doubling bifurcation solutions were given. The results obtained in this paper helps to provide insights to the mechanism of the tur...
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Refinement and Supplement of Phenomenology of Thermoelectricity
Issue:
Volume 6, Issue 5, September 2017
Pages:
96-107
Received:
15 June 2017
Accepted:
26 June 2017
Published:
28 August 2017
Abstract: Phenomenology of nonequilibrium thermodynamics based on independent thermodynamic forces with kinetic coefficients independent of the applied forces. Whereas the traditional thermoelectric phenomenology is based on the experimentally measured material parameters of the medium. At the same time, their historically emerging definitions have neither mathematical rigor nor consistency. And, as a result, the strict, developed in macroscopic phenomenological nonequilibrium thermodynamics patterns of relationship, in thermoelectricity are not completely considered. A rigorous phenomenological description of macroscopic thermoelectricity made it possible to reveal effects that had not been taken into account earlier when measuring thermoelectrics. In particular the effect of thermoelectric locking of current significantly influencing the measurement accuracy of conductivity of thermoelectrics has been ascertained. In addition, the phenomenology of thermoelectricity could be expanded both in terms of dimensionality and in terms of scale of size. Thereby it was succeeded to consider concentration effects even in the macroscopic case and to extend thermoelectricity phenomenology on micro- and the nano-level.
Abstract: Phenomenology of nonequilibrium thermodynamics based on independent thermodynamic forces with kinetic coefficients independent of the applied forces. Whereas the traditional thermoelectric phenomenology is based on the experimentally measured material parameters of the medium. At the same time, their historically emerging definitions have neither m...
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Performance Evaluation of Pyrolysis Cookstove Using Water Boiling Test
Teka Tesfaye Mengesha,
Ancha Venkata Ramayya
Issue:
Volume 6, Issue 5, September 2017
Pages:
108-116
Received:
20 March 2017
Accepted:
19 April 2017
Published:
12 September 2017
Abstract: For domestic energy – fuel sources biomass such as wood, animal dung and agricultural waste that are normally burned in traditional stove is used by the developing world. Diverse biomass resource is found in Ethiopia which can be used for energy through pyrolysis cook stove co-producing biochar. Specifically, coffee husks are the major solid residues from the handling and processing of coffee in the study area. The purpose of this study is to evaluate these Biochar producing pyrolysis cooking stove with respect to energy and emission. The selection of the stove design was made from both allothermal and autothermal type of pyrolysis cook stove. Both with and without biomass insertion was the experiment done for the allothermal stove design to understand the effect of the pyrolysis gas. The Water boiling test was used for the selected indirect and direct type stove design using wood and Corn cob respectively as fuel for testing stove efficiency. Both coffee husk and corncob as a biomass resource was used for generating pyrolysis gas and biochar using the selected indirect stove design. HOBO Carbon Monoxide Data logger and University of California Berkeley Particle Monitor device was used for measuring Carbon Monoxide and Particle Matter. The results from the water boiling test suggest that the indirect type stoves, without biomass insertion, average thermal efficiency was found between 15.86 to 18.6% during high power test and 20.02% average thermal efficiency was found for clay made stove during low power test. With biomass insertion corn cob and coffee husk the maximum average thermal efficiency is obtained during low power test using clay made stove 23.78% and 24.19% respectively. For direct type stoves the maximum and minimum thermal efficiency was found 34.11% for clay made stove and 20.4% for ELSA stove respectively during high power hot start phase.
Abstract: For domestic energy – fuel sources biomass such as wood, animal dung and agricultural waste that are normally burned in traditional stove is used by the developing world. Diverse biomass resource is found in Ethiopia which can be used for energy through pyrolysis cook stove co-producing biochar. Specifically, coffee husks are the major solid residu...
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