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81.
Experimental Study of Laminar Convective Condensation of Pure Vapor Inside an Inclined Circular Tube
Yuriy Lyulin Igor Marchuk Sergey Chikov Oleg Kabov 《Microgravity science and technology》2011,23(4):439-445
Convective condensation of pure ethanol vapor inside a smooth tube of inner diameter 4.8 mm and of length 200 mm is studied.
The experiments have been carried out at temperature 58°C corresponding to the pressure of 440 mbar, the vapor mass velocity
varying from 0.24 to 2.04 kg/(m2 s). The dependency of the Heat Transfer Coefficient (HTC) is investigated experimentally both subject to the temperature
difference between the saturated vapor and the wall and subject to the condenser inclination. The results show that the HTC
reduces with growth of the temperature difference. The dependency of the HTC on inclination has a maximum in the range 15°–35°
due to the complex gravity drainage mechanism of the condensed liquid. The results could be useful for development of compact
effective cooling systems for space and ground application. 相似文献
82.
83.
Ritesh Tipnis Jan Bernkopf Shijun Jia John Krieg Sergey Li Mark Storch Darin Laird 《Solar Energy Materials & Solar Cells》2009,93(4):442-446
Here we describe the fabrication of the largest (233 cm2 total area) organic photovoltaic (OPV) module (polymer:fullerene) to be certified by the National Renewable Energy Laboratory (NREL). OPV solar cells were fabricated at Plextronics by spin coating a blend of poly 3-hexylthiophene-2,5 diyl (P3HT) and [6,6] phenyl C61 butyric acid methyl ester (PCBM) on top of our hole transport layer (HTL), Plexcore® OC. In laboratory-scale devices (0.09 cm2), this system routinely exhibits power conversion efficiencies exceeding 3.7%. This P3HT:PCBM active layer and HTL ink system was used to scale up to the larger area module (15.2 cm×15.2 cm module size, i.e. 233 cm2 total area; 108 cm2 active area), which was certified by NREL as having 1.1% total area efficiency (3.4% active area efficiency). 相似文献
84.
Sergey Sigalov Mikhael D. Levi Gregory Salitra Doron Aurbach Alar Jänes Enn Lust Ion C. Halalay 《Carbon》2012,50(10):3957-3960
A TiC-derived carbon (TiC-CDC) was prepared, and the adsorption of large hexacyanocobaltate and tetrabutylammonium ions of approximately same size was examined on this carbon. While selectively absorbing these large ions, it rejects smaller chloride and ammonium ions in mixed electrolyte solutions. The result demonstrates the important role of electrostatic repulsive forces, space-efficient charge packing and hydrophobic ion interactions with the pore walls of TiC-CDC, similar to what is known for a variety of biological membranes. 相似文献
85.
Sergey G. Kopysov Aleksandr A. Erofeev 《The International journal of environmental studies》2015,72(3):380-385
The landscape conditions for forming the water balance and runoff from catchment areas can change considerably under the pressure of natural and anthropogenic factors. The role of hydromorphic transformation of landscapes is important for most of the Ob basin; it results in the paludification of the area. The specific parameter n is used in calculating water balance according to Mezentsev’s method of hydro-climatic calculations to take account of landscape conditions. We suggest determining this parameter’s value by geomorphological features of the landscapes using GIS tools. 相似文献
86.
We consider the routing open shop problem being a generalization of two classical discrete optimization problems: the open shop scheduling problem and the metric traveling salesman problem. The jobs are located at nodes of some transportation network, and the machines travel on the network to execute the jobs in the open shop environment. The machines are initially located at the same node (depot) and must return to the depot after completing all the jobs. It is required to find a non-preemptive schedule with the minimum makespan. The problem is NP-hard even on the two-node network with two machines. We present new polynomial-time approximation algorithms with worst-case performance guarantees. 相似文献
87.
Thomas Beer Tobias Meisen Rudolf Reinhard Sergey Konovalov Daniel Schilberg Sabina Jeschke Torsten Kuhlen Christian Bischof 《Production Engineering》2011,5(4):383-391
Computational simulations are used for the optimization of production processes in order to significantly reduce the need
for costly experimental optimization approaches. Yet individual simulations can rarely describe more than a single production
step. A set of simulations has to be coupled to each other to form a contiguous representation of a process chain. Eventually,
simulated results have to be analyzed by domain experts to gather insight from the preformed computations. In this paper,
we propose an IT infrastructure and software tools that aim at a rather non-intrusive way of coupling resources and domain
expert’s knowledge to enable the collaborative setup, execution and analysis of distributed simulation chains. We illustrate
the approach in the domain of materials processing. Beyond means originating from the domain of GRID computing for resource
management, a data integration component assures semantic data integrity between the simulation steps and stores simulation
data in an application independent way. Thus, we can transform this data into native formats for each simulation tool, and
finally into a format that allows for contiguous visualizations and an intuitive, comprehensive analysis of complete simulated
process chains. 相似文献
88.
Yuri V. Batygin Sergey F. Golovashchenko Andrey V. Gnatov 《Journal of Materials Processing Technology》2013,213(3):444-452
The paper is dedicated to the study of pulsed electromagnetic attraction processes which can deform ferromagnetic sheet metal materials such as low carbon steels using low frequency discharges. The analytical model based upon the solution of Maxwell equations explains that magnetic forces are prevailing over the Lorentz forces for low frequency discharges. For electromagnetic forming (EMF) processes employing ferromagnetic sheet metal blanks of low electrical conductivity with relatively slow electric discharges, the magnetic forces should be taken into account in order to achieve a correct representation of electromagnetic forces applied to the blank. An engineering estimate on the size of magneto-static forces and Lorentz-forces is the outcome of the analytical work. In addition to analytical work and validation of the proposed engineering estimate of attracting forces, a single turn coil is introduced which is more robust than previous designs with multiple frequencies and interrupted discharges. The simplified setup only requires a rather slow single frequency low voltage electric discharge which allows for using cheaper and longer life capacitors, substantially reduces the safety implications and also extends the life of the coil insulation. 相似文献
89.
Generalized communicating P systems are purely communicating tissue-like membrane systems with communication rules which allow the movement of only pairs of objects. In this paper, we study the power of these systems in the case of eight restricted variants of communication rules. We show that seven of these restrictions lead to computational completeness, while using the remaining one the systems are able to compute only finite singletons of non-negative integers. The obtained results complete the investigations of the computational power of generalized communicating P systems and provide further examples for simple architectures with simple functioning rules which are as powerful as Turing machines. 相似文献
90.
Biryukov SV 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2002,49(5):635-642
A new, fast, variation method (FVM) for determining an elastic strip response to stresses arbitrarily distributed on the flat side of the strip is proposed. The remaining surface of the strip may have an arbitrary form, and it is free of stresses. The FVM, as well as the wellknown finite element method, starts with the variational principle. However, it does not use the meshing of the strip. A comparison of FVM results with the exact analytical solution in the special case of shear stresses and a rectangular strip demonstrates an excellent agreement 相似文献