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21.
Cogeneration from renewable energy sources has been universally proposed as a partial alternative to the solution of our nation's energy problems. New technical, safety, and operational problems are introduced when this generation is placed into a distribution grid. Addressed is the problem of distribution system protection with the introduction of cogeneration sources and the changes and modifications which may be required in the application of present-day protection devices. A sample system is considered, and system protection and coordination with and without cogeneration has been calculated through a digital fault and system protection coordination program. The results indicate through the study of several systems that additional coordination and protection considerations will be required when sizable cogeneration sources are introduced to maintain a high degree of reliability and service continuity. 相似文献
22.
Toluenesulfonate-acyl esters of ethylene glycol and other 1,2-diols as industrial antioxidants with cupric ion 总被引:2,自引:0,他引:2
Yongyi?Julia?Jiang Earl?G.?HammondEmail author 《Journal of the American Oil Chemists' Society》2002,79(8):791-796
Ethylene glycol esters of soybean oil FA increased in viscosity much more slowly than methyl or glycerol esters when oxidized
at 105°C in the presence of flowing air and colloidal copper. This increased stability was caused by a minor constituent of
the ethylene glycol esters, which was shown by MS to be a mixed ethanediol fatty acylate p-toluenesulfonate (EFAT). The p-toluenesulfonate group came from the catalyst used in the formation of the ethylene glycol esters. EFAT was quantified by
UV spectrometry, HPLC, or GC of the acyl group that it contains. EFAT could be synthesized in good yield by reacting ethylene
glycol, a FA, and p-toluenesulfonic acid (TSA) in a 1∶1∶1 molar ratio using a benzene azeotrope to remove water of esterification. EFAT increased
the time required for the polymerization of soybean oil by about 27 times but required concentrations of 2–5% by weight. EFAT
made with a variety of FA were active in delaying viscosity increase. Ethyl and decyl p-toluenesulfonate were inactive. Replacing ethylene glycol by glycerol and 1,2-propylene glycol but not by 1,3-propylene glycol
resulted in active EFAT. TSA itself delayed the polymerization of soybean oil, especially in the presence of free ethylene
glycol and FA, but this probably was caused by formation of EFAT during the oxidation test. Colloidal copper could be replaced
by cupric ion. EFAT-copper appeared to act as an antioxidant by destroying hydroperoxides without initiation of free radical
chains. 相似文献
23.
Ohsang Kwon Kevin Nowka Earl E. Swartzlander Jr. 《The Journal of VLSI Signal Processing》2002,31(2):77-89
3:2 counters and 4:2 compressors have been widely used for multiplier implementations. In this paper, a fast 5:3 compressor is derived for high-speed multiplier implementations. The fast 5:3 compression is obtained by applying two rows of fast 2-bit adder cells to five rows in a partial product matrix. As a design example, a 16-bit by 16-bit MAC (Multiply and Accumulate) design is investigated both in a purely logical gate implementation and in a highly customized design. For the partial product reduction, the use of the new 5:3 compression leads to 14.3% speed improvement in terms of XOR gate delay. In a dynamic CMOS circuit implementation using 0.225 m bulk CMOS technology, 11.7% speed improvement is observed with 8.1% less power consumption for the reduction tree. 相似文献
24.
Iterative MILP methods for vehicle-control problems 总被引:3,自引:0,他引:3
Mixed-integer linear programming (MILP) is a powerful tool for planning and control problems because of its modeling capability and the availability of good solvers. However, for large models, MILP methods suffer computationally. In this paper, we present iterative MILP algorithms that address this issue. We consider trajectory-generation problems with obstacle-avoidance requirements and minimum-time trajectory-generation problems. These problems involve vehicles that are described by mixed logical dynamical equations, a form of hybrid system. The algorithms use fewer binary variables than standard MILP methods, and require less computational effort. 相似文献
25.
With the exception of thalamotomy for drug-refractory tremor, surgical therapy for Parkinson's disease has been almost abandoned as treatment for Parkinsonian symptoms between 1965 and 1985. Reasons for this development relate to inconsistent postoperative results, complications associated with stereotactic surgical techniques and, most importantly, the advent of levodopa, which is still considered to be the gold standard in pharmacotherapy for Parkinson's disease. However, both, the long-term experience with L-DOPA therapy on the one hand and the progress of advanced stereotactic techniques and fetal graft research on the other hand have lead to reconsideration of surgical therapy in Parkinson's disease for patients, who can not be treated satisfactorily with medication. Both lesions (via thermocoagulation) and/or neurostimulation (via chronic intracerebral implantation of electrodes) in thalamic nuclei (nucleus ventralis oralis posterior/intermedialis thalami; VOP/VIM) may alleviate rest tremor in PD patients. In principle neurostimulation has the significant advantage of reversibility with regard to side effects in comparison to lesion surgery. Furthermore ventro-posterior pallidotomy or chronic stimulation in this structures may ameliorate bradykinesia and levodopa-induced dyskinesias. Additionally, "switching-off" the subthalamic nucleus by neurostimulation has been reported to reduce rigidity, bradykinesia and levodopa-induced ON-OFF-fluctuations. On the other hand, neuronal transplantation of fetal nigral dopamine precursor cells aims at restoring the striatal dopamine deficit. Both animal and clinical experiments have shown that fetal grafts survive intrastriatal transplantation and may ensue moderate to satisfactory improvements, especially in regard to bradykinesia and ON-OFF-fluctuations. Further progress in the field of neuronal transplantation will largely depend on the development of alternative cell resources. 相似文献
26.
MJ Clemons E Marshall J Dürig K Watanabe A Howell D Miles H Earl J Kiernan A Griffiths K Towlson P DeTakats NG Testa M Dougal MG Hunter LM Wood LG Czaplewski A Millar TM Dexter BI Lord 《Canadian Metallurgical Quarterly》1998,92(5):1532-1540
BB-10010 is a variant of the human form of macrophage inflammatory protein-1alpha (MIP-1alpha), which has been shown in mice to block the entry of hematopoietic stem cells into S-phase and to increase their self-renewal capacity during recovery from cytotoxic damage. Its use may constitute a novel approach for protecting the quality of the stem cell population and its capacity to regenerate after periods of cytotoxic treatment. Thirty patients with locally advanced or metastatic breast cancer were entered into the first randomized, parallel group controlled phase II study. This was designed to evaluate the potential myeloprotective effects of a 7-day regimen of BB-10010 administered to patients receiving six cycles of 5-fluorouracil (5-FU), adriamycin, and cyclophosphamide (FAC) chemotherapy. Patients were randomized, 10 receiving 100 microgram/kg BB-10010, 11 receiving 30 microgram/kg BB-10010, and nine control patients receiving no BB-10010. BB-10010 was well-tolerated in all patients with no severe adverse events related to the drug. Episodes of febrile neutropenia complicated only 4% of the treatment cycles and there was no difference in incidence between the treated and nontreated groups. Studies to assess the generation of progenitor cells in long-term bone marrow cultures were performed immediately preceding chemotherapy and at the end of six dosing cycles in 18 patients. Circulating neutrophils, platelets, CD 34(+) cells, and granulocyte/macrophage colony-forming cell (GM-CFC) levels were determined at serial time points in cycles 1, 3, and 6. The results showed similar hemoglobin and platelet kinetics in all three groups. On completion of the six treatment cycles, the average pretreatment neutrophil levels were reduced from 5.3 to 1.7 x 10(9)/L in the control patients and from 4.3 to 1.9 and 4.5 to 2.5 x 10(9)/L in the 30/100 microgram/kg BB-10010 groups, respectively. Relative to their pretreatment values, 50% of the patients receiving BB-10010 completed the treatment with neutrophil values significantly higher than any of the controls (P = .02). Mobilization of GM-CFC was enhanced by BB-10010 with an additional fivefold increase over that generated by chemotherapy alone, giving a maximal 25-fold increase over pretreatment values. Bone marrow progenitor assays before and after this standard regimen of chemotherapy indicated little long-term cumulative impairment to recovery from chemotherapy. Despite the limited cumulative damage to the bone marrow, which may have minimized the protective value of BB-10010 during this regimen of chemotherapy, better recovery of neutrophils in the later treatment cycles with BB-10010 was indicated in a number of patients. 相似文献
27.
28.
Weeks Lloyd E. Harris Jay C. Brown Earl L. 《Journal of the American Oil Chemists' Society》1954,31(6):254-257
Journal of the American Oil Chemists' Society - A dynamic foam test for evaluation of hand-dish-washing compositions has been developed which gives good correlation with semipractical plate... 相似文献
29.
The flavor intensity of soybean oils was evaluated in emulsions stabilized with gum acacia. A 10-point scale was used with
a blank to establish the bland end of the scale and a standard diacetyl solution to establish a point near midscale. Tasting
oils in emulsion gave significantly different scores than tasting oil directly. Evaluation in emulsion decreased panel error
for poor quality oils but not for very bland oils. At least six samples could be tasted in emulsion without casusing panel
fatigue or reducing accuracy. The concentration of oil in the emulsion could be adjusted to increase sensitivity to weak flavors
or improve the evaluation of intensely flavored oils. Soybean oils containing various amounts of linolenic acid were evaluated
by the emulsion method, and those with lesser amounts of linolenic acid were shown to be more stable. A gas Chromatographic
total volatile method was shown to correlate fairly well with sensory evaluation of oils tasted in emulsions under conditions
where both flavors scores and total volatiles changed significantly with time.
Journal Paper no. J-10442 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project no. 2143. 相似文献
30.