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991.
The design problem of a multiproduct dehydration plant involving continuous conveyor-belt dryers utilised for the dehvdration of agricultural products over a fmite tim horizon, is presented. The peculiarities of the problem under demand-varying market patterns and time-variable market prices of raw materials are underlined. Limitations imposed by storage capacity, custormer orders, and constraints dictated by the process itself, are also taken into consideration. The overall problem is cast into a MINLP formulation involving the total annual cost of the plant as its objective function. This was infered by deducing the mathematical model of conveyor-belt dryers. Repeated evaluation of the total annual cost for various structures and operating points, allowed the determination of overall performance characteristic operational and structural curves. approximated by suitable mathematical expressions. A test case is presented in order to demonstrate the effectiveness of the proposed approach. 相似文献
992.
993.
E. D. Reese K.-H. Schwalbe † 《Fatigue & Fracture of Engineering Materials & Structures》1993,16(3):271-280
An alternative approach for determining J-R curves from a single specimen test based on the normalization technique is proposed. The procedure requires only the load versus load-line displacement record and the final crack length in order to derive the J-R curve. The method has been applied to metal and polymers of various geometries and was verified by comparison with J-R curves obtained from potential drop and multiple specimen techniques. 相似文献
994.
Z Popovi? Z Jovanovi? M Todori? I Butkovi? D Nikoli? 《Canadian Metallurgical Quarterly》1997,54(5):425-435
To clarify the histogenesis and differentiation potential of central neurocytoma, a pathological investigation of seven tumors from three patients was conducted using immunohistochemistry and ultrastructural analysis in addition to systematic in vitro studies. Six tumors were studied immunohistochemically and five were examined ultrastructurally. All cases that were immunostained were positive for synaptophysin in nuclear-free neuropil islands. In five tumors, a few tumor cells, in addition to reactive astrocytes, were positive for glial fibrillary acidic protein (GFAP). Vimentin staining was also positive in a few tumor cells of five specimens. Neurofilament staining was always negative. All cases for which ultrastructure was examined showed various synaptic abnormalities. Cultured cells were subdivided into three distinct tumor cell types: neuronal cells which stained for neurofilament proteins with neurosecretory granules; small flat undifferentiated cells with a high nuclear-cytoplasmic ratio and scant cytoplasmic organelles; and small round or multipolar astrocytic cells with 10-nm intermediate filaments which stained for GFAP. Our tissue culture studies disclosed that cultured neurocytoma cells form a cellular mosaic similar to subependymal plate layers that are composed of mitotically active cells, neurons and glia. 相似文献
995.
The authors describe a robust channel prediction technique for a direct sequence spread spectrum (DS-SS) system in a fast fading environment. Coherent diversity reception is employed for improved performance. To estimate the channel response, an FIR type linear prediction filter is employed for each RAKE tap. The stability of the decision directed receiver is achieved through differential encoding of the data bits. It is demonstrated through simulations that the performance of the proposed decision directed receiver is better than a receiver which relies on a pilot signal 相似文献
996.
997.
The author presents a personal account of the search for a design procedure for Yagi-Uda antenna arrays yielding a maximum gain, or directivity if element losses are neglected. Results on current distributions in the array are briefly reviewed. The analytical approach used to achieve gain optimization by means spacing and length perturbations is sketched. By using both spacing and length perturbations, it was possible to find the optimized array analytically in a systematic way, some examples having gain increases of nearly 80%. The effects of finite dipole radius and mutual coupling were included in the theoretical treatment 相似文献
998.
999.
Corrosion tests of selected metallic materials in the system acetic acid/acetic anhydride The corrosion behaviour of the ferritic austenitic stainless steels X2 CrNiMoN 22 5 (UNS S31803) and X2 CrNiMoN 25 7 4 (UNS S32750), the nickel base alloy NiMo16Cr16Ti (alloy C-4) and the titanium grades Ti2 (Grade 2) and Ti2Pd (Grade 7) was investigated by immersion tests in boiling mixtures of acetic acid and acetic anhydride in the presence of air. All materials tested were corrosion resistant in acetic acid and acetic anhydride but were corroded rapidly by the mixtures with a corrosion loss up to 1 mm/a, except the nickel base alloy (alloy C-4). It was corrosion resistant in all solutions with a corrosion loss not exceeding 0.01 mm/a. Electrochemical tests show that all materials tested exhibit stable passivity in glacial acetic acid and active corrosion in the presence of 10% acetic anhydride. 相似文献
1000.
Multiple stroke lightning ground flashes can impose surges of exceptional severity on the arresters used to protect exposed distribution system equipment. This paper reports laboratory and analytical studies of the effects of representative multiple impulse currents on zinc-oxide surge arresters of distribution class. The results indicate that sextuple 8/20 μs currents can cause damage to arresters not evident with standard lightning current tests and so are worthy of inclusion in testing Standards 相似文献