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61.
A constraint-based variability modeling framework 总被引:1,自引:0,他引:1
Sven J?rges Anna-Lena Lamprecht Tiziana Margaria Ina Schaefer Bernhard Steffen 《International Journal on Software Tools for Technology Transfer (STTT)》2012,14(5):511-530
Constraint-based variability modeling is a flexible, declarative approach to managing solution-space variability. Product variants are defined in a top-down manner by successively restricting the admissible combinations of product artifacts until a specific product variant is determined. In this paper, we illustrate the range of constraint-based variability modeling by discussing two of its extreme flavors: constraint-guarded variability modeling and constraint-driven variability modeling. The former applies model checking to establish the global consistency of product variants which are built by manual specification of variations points, whereas the latter uses synthesis technology to fully automatically generate product variants that satisfy all given constraints. Each flavor is illustrated by means of a concrete case study. 相似文献
62.
Uwe Heisel Wiliam Zaloga Dmitrii Krivoruchko Michael Storchak Liubov Goloborodko 《Production Engineering》2013,7(6):639-645
In the last decades, mesh-free methods for simulating various cutting processes have been used very widely as they can eliminate numerical problems in the simulation of material failure and large plastic deformations. This paper deals with the results from modelling the orthogonal cutting of AISI 1045 steel using smoothed particle hydrodynamics (SPH) method. Moreover, it is determined how the parameters of the SPH solver such as initial smoothing length, initial particle density and coefficient for the timestep increase affect the prediction error for the values of cutting force and chip compression ratio as well as computing time. The optimum values of the SPH solver parameters are determined by minimising an objective function. The best balance between the prediction error of machining variables and computing time is achieved for an initial particle density of 40 μm and a coefficient for the timestep increase of 0.4. 相似文献
63.
Lei Xie Zhe Li Jiusun Zeng Uwe Kruger 《American Institute of Chemical Engineers》2016,62(12):4334-4345
On‐line modeling of multivariate nonlinear system based on multivariate statistical methods has been studied extensively due to its industrial requirements. In order to further improve the modeling efficiency, a fast Block Adaptive Kernel Principal Component Analysis algorithm is proposed. Comparing with the existing work, the proposed algorithm (1) does not rely on iterative computation in the calculating process, (2) combines the up‐ and downdating operations to become a single one (3) and describes the adaptation of the Gram matrix as a series of rank‐1 modification. In addition, (4) the updation of the eigenvalues and eigenvectors is of and high‐precision. The computational complexity analysis and the numerical study show that the derived strategy possesses better ability to model the time‐varying nonlinear variable interrelationships in process monitoring. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4334–4345, 2016 相似文献
64.
Melt spun matrix fibers of toughened polypropylene copolymers modified by high energy electrons 下载免费PDF全文
Binary blends of polypropylene (PP) and ethylene‐octene copolymer (EOC) are prepared by continuous electron‐induced reactive processing at various mass ratios of the blend components and various doses without adding of any grafting agents. The influence of mass ratio and dose is investigated in order to get the optimum processing behavior of toughened PP as well as optimum properties of resulting fibers. It is found that toughened PP with a PP/EOC blend ratio of 97.5–2.5 mass % can be used advantageously as a matrix component for the process of online spinning of glass fiber/toughened PP hybrid yarns. Such hybrid yarns belong to one of the most advanced production methods for the manufacturing of fiber reinforced thermoplastic composites with an increased mechanical performance. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44011. 相似文献
65.
Radiation‐induced graft copolymerization of hydroxyethyl methacrylate with hydroxyethyl acrylate, acrylic acid or glycidyl methacrylate on ethylene tetrafluoroethylene (ETFE) films allow for tailor‐made synthesis of membranes for high and low temperature fuel cell applications. According to the operating temperatures proton conductivity may be achieved via doping with phosphoric acid or a two‐step sulfonation of the functional monomers. Fuel cell tests provide power densities and internal resistances, which indicate that the membranes are suitable for high and low temperature fuel cells. 相似文献
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68.
Higher Hydrocarbon Production through Oxidative Coupling of Methane Combined with Hydrogenation of Carbon Oxides 下载免费PDF全文
In the production of higher hydrocarbons, combining oxidative coupling of methane (OCM) with hydrogenation of the formed carbon oxides in a separate reactor provides an alternative to the currently applied methane conversion to syngas followed by Fischer‐Tropsch synthesis. The effects of CH4:O2 feed ratio in the OCM reactor and partial pressures of H2 or/and H2O in the hydrogenation reactor were analyzed to maximize production of C2+ hydrocarbons and reduce COx formation. The highest C2+ yield was achieved with low CH4:O2 feed ratio for OCM and removal of the formed water before entering the hydrogenation reactor. 相似文献
69.
Monica Badila Christoph Jocham Wenbiao Zhang Thomas Schmidt Günter Wuzella Uwe Müller Andreas Kandelbauer 《Progress in Organic Coatings》2014
The powder coating of veneered particle boards by the sequence electrostatic powder application – powder curing via hot pressing is studied in order to create high gloss surfaces. To obtain an appealing aspect, veneer sheets were glued by heat and pressure on top of particle boards and the resulting surfaces were used as carrier substrates for powder coat finishing. Prior to the powder coating, the veneered particle board surfaces were pre-treated by sanding to obtain good uniformity and the boards were stored in a climate chamber at controlled temperature and humidity conditions to adjust an appropriate electrical surface resistance. Characterization of surface texture was done by 3D microscopy. The surface electrical resistance was measured for the six veneers before and after their application on the particle board surface. A transparent powder top-coat was applied electrostatically onto the veneered particle board surface. Curing of the powder was done using a heated press at 130 °C for 8 min and a smooth, glossy coating was obtained on the veneered surfaces. By applying different amounts of powder the coating thickness could be varied and the optimum amount of powder was determined for each veneer type. 相似文献
70.
E. Vilsmaier Markus Grosse Wolf-Rüdiger Schlag Gunther Milch Uwe Bergstrßer Andreas Ritter von Onciul 《Advanced Synthesis \u0026amp; Catalysis》1996,338(1):479-484
6-Piperidino-3-azabicyclo[3.1.0]hexane-6-carboxamide diastereomers 1a and 2a represent conformationally rigid analogues of 3a which is a building block in some pharmaceutical compounds. A new access to these compounds 1a and 2a was found via the cleavage of bicyclic N,N-acetal 6 with hydrocyanic acid as the stereodetermining step. Reaction of derivatives 1a and 2a with bromodiphenyl-butyronitrile 14 gave cyclopiritramide isomers 1c and 2c , respectively. Qualitative preliminary investigations showed different affinities of 1c and 2c to the opiate-μ receptor. These results were discussed on the basis of an X-ray structural analysis of cyclopiritramide isomer 2c . 1-Benzylcyclopiperidine derivatives 1d and 2d were used as model systems for studying the conformation of cyclopiritramide isomer 1c and 2c , respectively. 相似文献