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[en] Nucleophilic substitution reactions of 5-XC4H2 (S)C(O)OC6H3 -2-Y-4-NO2 (1) promoted by 4-Z-C6H4O −/4-Z-C6H4OH in 20 mol % dimethyl sulfoxide (DMSO)(aq) have been studied kinetically. The reactions exhibited second-order kinetics with βacyl = −2.52 to −2.83, ρ(x) = 2.81–3.16, βnuc = 0.88–0.04 and βlg = −0.94, respectively. The results have been interpreted with an addition–elimination mechanism in which the nucleophilic attack occurs in the rate-determining step. Comparison with existing data reveals that the rate-determining step changes from the second to the first step by the change in the nucleophile from R2NH/R2NH2 + to 4-Z-C6H4O −/4-Z-C6H4OH
[en] The U.S. Department of Energy's Vehicle Technologies Office, Materials area commissioned a study to model and assess manufacturing economics of alternative design and production strategies for a series of lightweight vehicle concepts. In the first two phases of this effort examined combinations of strategies aimed at achieving strategic targets of 40% and a 45% mass reduction relative to a standard North American midsize passenger sedan at an effective cost of $3.42 per pound (lb) saved. These results have been reported in the Idaho National Laboratory report INL/EXT-14-33863 entitled Vehicle Lightweighting: 40% and 45% Weight Savings Analysis: Technical Cost Modeling for Vehicle Lightweighting published in March 2015. The data for these strategies were drawn from many sources, including Lotus Engineering Limited and FEV, Inc. lightweighting studies, U.S. Department of Energy-funded Vehma International of America, Inc./Ford Motor Company Multi-Material Lightweight Prototype Vehicle Demonstration Project, the Aluminum Association Transportation Group, many United States Council for Automotive Research's/United States Automotive Materials Partnership LLC lightweight materials programs, and IBIS Associates, Inc.'s decades of experience in automotive lightweighting and materials substitution analyses.
[en] Measurement of process parameters in reactive metals processing, such as actinides, is extremely difficult due to dynamic nature of system operating at high temperatures and under protective atmospheres. In addition, performing studies with radioactive strategic metals is, generally, prohibitively expensive with significant safety concerns. This study discusses the use of cerium metal to simulate the pyrometallurgical characteristics of plutonium. Design parameters relating to ceramic component arrangement, process parameters relating to electrolyte behavior and operating parameters relating to cell temperature, anode stirring speed, current density and back emf for electrorefining have been studied. Molten tin, gallium, iodine and antimony-cadmium alloy have also been used to study the different parameters involved. Validity and justification of these measurements has been discussed
[en] The tests were part of the CFC replacement program to identify and test alternate coolants to replace CFC-114 being used in the uranium enrichment plants at Paducah and Portsmouth. The coolants tested, C4F10 and C4F8, were selected based on their compatibility with the uranium hexafluoride process gas and how well the boiling temperature and vapor pressure matched that of CFC-114. However, the heat of vaporization of both coolants is lower than that of CFC-114 requiring larger coolant mass flow than CFC-114 to remove the same amount of heat. The vapor pressure of these coolants is higher than CFC-114 within the cascade operational range, and each coolant can be used as a replacement coolant with some limitation at 3,300 hp operation. The results of the CFC-114/C4F10 mixture tests show boiling heat transfer coefficient degraded to a minimum value with about 25% C4F10 weight mixture in CFC-114 and the degree of degradation is about 20% from that of CFC-114 boiling heat transfer coefficient. This report consists of the final reports from Cudo Technologies, Ltd
[en] A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression stress-relaxation (CSR) tests and field surveillance are also on going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF.
[en] The principal conclusion from the programme of work carried out by the CEGB was that Carbohydrazide appeared to be the most promising alternative to hydrazine for boiler feedwater conditioning. It is an effective oxygen scavenger at higher feedwater temperatures, its breakdown products are not a serious threat to circuit materials and it is safer to handle than hydrazine. The main disadvantages, at the time of the study, appeared to be the lack of a simple reliable method for measuring residual carbohydrazide in feedwater and a cost for the alternative chemical of up to 20 times that of hydrazine. (orig.)
[en] The transport critical current density, Jct of TI(Sr1-xNdx)2CaCu2O7 (x= 0.1, 0.2 and 0.3) high temperature superconductors were measured at various temperatures. X-ray diffraction patterns indicate that all samples consist of mainly of the 1212 phase. The variation of Jct with Nd concentration, temperature and Tc were scaled using a universal function. By plotting Jct versus Tnc(x) and [1-(T/Tc)2]m, we can divide the temperature dependencies of Jct into two regions. In each region, a linear relationship is suggested to hold between Jct and [1-(T/Tc)2]m. For x=0.1, a relatively large exponent m in the range 40 - 50 K is observed, but a lower value is observed for a higher temperature range, 55 - 60 K. Average m for x = 0. 1 in the range 40 - 70 K is 1.8 but for x=0.2 and 0.3, m is 0.6 and 1.2, respectively. This can be interpreted as an indication that there is a change in the elementary flux pinning force which is responsible for sustaining the supercurrent. A self-field approximation indicates that Nd substitution lowers the distance between pinning centers (Lc). (author)
[en] The perturbations in the dose distribution caused by a hip prosthesis when treating pelvic cancers have been evaluated and found to be significant by several investigators. Treatment techniques not including the prosthesis are often not the best choice. The goal of this study is to investigate the feasibility and usefulness of design of compensators in routine clinical practice for any kind of hip prosthesis. The calculation procedures and the algorithms developed by the authors for generating the compensators are described for two systems: one based on a locally developed 3-D computerized treatment planning system and an other one practicable in any institution which does not have access to a 3D treatment planning system or CT. The methodology to create the compensators for a patient is explained. To evaluate the constructed compensators in phantom and in vivo measurements were performed. The results are presented along with a comparison between the two methods