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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The international journal of advanced manufacturing technology 15 (1999), S. 38-48 
    ISSN: 1433-3015
    Keywords: Key words.Alternative interpretation; Feature-based design; Feature extraction; STEP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: One of the major difficulties in extracting machining features is the lack of a systematic methodology to generate alternative ways of manufacturing a machined part. Most of the early research in feature extraction and process planning has not considered this aspect, and has focused on the generation of a single interpretation. In this paper, we propose a feature-based approach to generating alternative interpretations of machining features from a feature-based design model. The proposed approach simplifies the generation of alternative machining feature models by using information on feature which is captured and maintained during feature-based model-ling and machining feature extraction. A set of machining features is incrementally extracted during the feature-based design process of a machined part. A feature conversion process converts each design feature into a machining feature or a set of machining features by using information on the geometry and the feature. Using reorientation, reduction, and/or splitting operations, alternative models are generated from the sets of extracted machining features. During the execution of each operation, unpromising models are pruned by using criteria such as minimising the number of accessibility directions. The machining features and their precedence relationships are represented in a STEP-based machining feature graph for the purpose of data exchange.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 53 (1991), S. 279-281 
    ISSN: 1432-0649
    Keywords: 42.65 ; 72.40 ; 78.65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Photoconductivity measurements on a stable photocrosslinkable nonlinear optical polymer — PVCN (polyvinylcinnamate)/CNNB-R (3-cinnamoyloxy-4-[4-N,N-diethylamino)-2-cinnamoyloxy phenylazo] nitrobenzene) are reported. Photoconductivity in this polymer system, in both crosslinked and uncrosslinked states, was observed without introducing any sensitizer or carrier-transport agents. Absorption of CNNB-R (λpeak=518 nm) results in photocarrier generation and it is conjectured that CNNB-R also plays a role in the carrier transport. Such polymers are candidate materials for photorefraction.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 11 (1992), S. 1043-1045 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 14 (1995), S. 124-128 
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 22 (1992), S. 512-516 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The charge-discharge characteristics of polyaniline (PAn)-Nafion®-PAn composite films used as rechargeable batteries were investigated. The batteries were formed chemically by sandwiching Nafion® between two thin layers of PAn-Nafion® composite in equilibrium with various electrolytes. It was found that cells with LiClO4 in propylene carbonate as electrolyte showed the highest capacity. The charge and discharge performance of the battery was almost independent of the choice of anions but was significantly affected by cation size. This may indicate that the insertion or removal of charge-compensating electrolyte cations from the composite layer was responsible for the redox of PAn during the charge and discharge cycles.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 23 (1993), S. 1031-1038 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electrodeposited polyaniline (PANT) in the emeraldine oxidation state was used as the electrodes of open rechargeable cells containing 1 m HClO4 as the electrolyte. The cells could be charged at very high hourly rates to 85% of the redox charge in the leucoemeraldine-emeraldine transition of the polymer. Contrary to normal behaviour of rechargeable cells, the coulombic efficiency improved with increasing rates of charge injection and withdrawal. This is attributed to less charge being dissipated by self-discharge at high rates of discharge. The poor charge retention was caused by reactions between the charged electrodes and their environment. The decrease in cell voltage on standing may also be induced by internal redox reactions of PANT of different oxidation states present at the electrodes as a result of incomplete oxidation or reduction during cell operation. Ultraviolet (u.v.) spectroscopy of the charged electrodes identified mostly protonated leucoemeraldine at the negative electrode and pernigraniline at the positive electrode. The irreversibility in the oxidation from the emeraldine state to the pernigraniline state accounts mostly for the degeneration of cell performance after prolonged cycling.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied electrochemistry 22 (1992), S. 738-742 
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Thin films of polypyrrole (PPy) and polyaniline (PANi) were electrochemically deposited on stainless steel substrate under potentiostatic control. Secondary batteries were assembled using these polymers as active electrode materials and propylene carbonate (PC) solutions of tetraethyl ammonium perchlorate (TEAP) as the electrolyte. In repeated charge and discharge tests, the all PANi cells performed better than the PPy-PANi cells in voltage characteristics, recyclability, charge retention and coulombic efficiency. There appears to be an optimum charging current for the polymer cells and charging the cells at rates notably different from the optimum value reduced the cell performance substantially. It is suggested that the cells operate under kinetic control and charging at extreme rates either reduces the participation of polymer redox in the overall cell operation or produces mass transfer limitations.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 29 (1994), S. 6495-6500 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The particle size distributions of cobalt powders prepared by reactive deposition were examined and correlated with the deposition condition. In reactive deposition, a Co(OH)2 colloid layer was formed at the electrode surface upon reduction of dissolved oxygen. The colloid layer accelerated the decrease in interfacial Co2+ concentration and inhibited crystal growth of the metal, and was therefore instrumental in the formation of fine cobalt particles. The powders from reactive deposition were statistically a factor of two finer and of more uniform size distribution than those from normal electrodeposition. It was found that both the reactive deposition of cobalt powders and the reactive deposition of porous cobalt structures were driven by the same kinetic factors, namely the requirement of maintaining an effective presence of the Co(OH)2 colloid layer at the electrode surface. Hence a similar dependence on deposition conditions for both processes was obtained.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 16 (1981), S. 2590-2596 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of Cr, Ni, Mo, Si and Cu on the diffusivity of hydrogen inα-iron is studied in the temperature range of 160 to 430° C at a hydrogen pressure of 1 atm. The diffusivity of hydrogen was determined by absorption rate experiments using Sievert's type apparatus. The results show that the diffusivity of hydrogen in iron alloys decreases and the activation energy increases, as the concentration of the alloying elements increases, except Cu and Ni. The trapping parameters of hydrogen in iron alloys on the basis of Oriani's approach are calculated. The results show that Si, Mo and Cr are in order of increasing trap energy and that Cu and Ni have a negligible effect on hydrogen trapping. This can be explained by taking account of both chemical affinity effects and elastic strain effects of alloying elements on hydrogen trapping.
    Type of Medium: Electronic Resource
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