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1.
P. N. Sibisi A. P. I. Popoola N. K. K. Arthur S. L. Pityana 《The International Journal of Advanced Manufacturing Technology》2020,107(3):1163-1178
Direct laser metal deposition (DLMD) is a breaking edge laser-based additive manufacturing (LAM) technique with the possibility of changing the perception 相似文献
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Clément Perrinet Edwin-Joffrey Courtial Arthur Colly Christophe Marquette René Fulchiron 《大分子材料与工程》2021,306(2):2000553
For manufacturing parts of very soft materials by liquid deposition modeling (e.g., to mimic living soft tissues), formulations of 3D-printable polydimethylsiloxane have been developed, with the aim of increasing the yield stress of the liquid and reducing the final mechanical modulus. In the present work, suspensions of solid-like hydrogel particles, which are easily 3D-printable, are prepared in order to generate yield stress, and the suspended phase is removed after manufacturing by taking advantage of the thermo-reversibility of the hydrogel behavior, resulting in porosity, which reduces the final rigidity. The reported approach is even more efficient than a previous approach based on emulsion formulations. 相似文献
5.
In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed sediment samples were collected. All samples were size-limited (< 63 µm) to facilitate spatial and/or temporal comparisons, and subsequently analyzed for a variety of chemical constituents including major (e.g., Fe, Al,) and trace elements (e.g., Cu, Zn, Cd), nutrients (e.g., P), and carbon. The analyses yielded total (≥ 95% of the concentrations present), rather than total-recoverable chemical data.Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on sediment chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (≤ 27 p km− 2) density, low percent urban (≤ 5%), agricultural or undeveloped areas. The NAWQA baseline values are similar to those found in other national and global datasets. Further, it appears that upstream/underlying rock type has only a limited effect (mostly major elements) on sediment chemistry. The only land-use category that appears to substantially affect sediment chemistry is percent urban, and this result is mirrored by population density; in fact, the latter appears more consistent than the former. 相似文献
6.
Natural ventilation in buildings: measurement in a wind tunnel and numerical simulation with large-eddy simulation 总被引:2,自引:0,他引:2
Yi JiangDonald Alexander Huw JenkinsRob Arthur Qingyan Chen 《Journal of Wind Engineering & Industrial Aerodynamics》2003,91(3):331-353
Natural ventilation in buildings can create a comfortable and healthy indoor environment, and can save energy compared to mechanical ventilation systems. In building design the prediction of ventilation can be difficult; cases of wind-driven single-sided ventilation, where the effects of turbulence dominate, are particularly problematic to simulate. In order to investigate the mechanism of natural ventilation driven by wind force, large-eddy simulation (LES) is used. In the meanwhile, detailed airflow fields, such as mean and fluctuating velocity and pressure distribution inside and around building-like models were measured by wind tunnel tests and compared to LES results for model validation. Three ventilation cases, single-sided ventilation with an opening in windward wall, single-sided ventilation with an opening in leeward wall, and cross ventilation, are studied. In the wind tunnel, a laser Doppler anemometry was used to provide accurate and detailed velocity data. In LES calculations, two subgrid-scale (SS) models, a Smagorinsky SS model and a filtered dynamic SS model, were used. The numerical results from LES are in good agreement with the experimental data, in particular with the predicted airflow patterns and velocities around and within, and the surface pressures over, the models. This is considered to establish confidence in the application of the LES methods to the calculation of ventilation in buildings, in particular for single-sided ventilation cases. 相似文献
7.
Arthur L. Silvers 《Papers in Regional Science》1989,67(1):147-158
A region's producing sectors compete in national markets with other regions, and its output growth therefore depends on changes in the region's sectoral input costs relative to those in other regions. In this model, production costs are taken as dependent upon wages and other payments to local factors and upon costs of interindustry inputs, the producers of which pay wages and other factor costs locally or, if the inputs are imported, in other regions. After consideration of conditions by which regional commodity supply functions can be aggregated, sectoral commodity prices and the regional production of national and local goods are endogenously determined in a computable equilibrium system within a balanced regional model framework. 相似文献
8.
John W. Arthur Armond E. Lemke Vincent R. Mattson Barbara J. Halligan 《Water research》1974,8(3):187-193
Amphipods, Gammarus pseudolimnaeus Bousfield and fathead minnows, Pimephales promelas Rafinesque, were submitted to acute (96-h) and chronic (generation-cycle) bioassays with sodium nitrilotriacetic acid (NTA). All measurements are reported as Na3NTA. The average 96-h TL50 values under flow-through conditions were 98 mg 1−1NTA for the amphipod and 114 mg 1−1 for the fathead minnow. The acute toxicity of NTA was caused in part by the high pH resulting from the addition of large amounts of NTA (> 100 mg 1−1) to soft water. Controlling pH reduced the lethality of NTA by at least one-half to fathead minnow larvae. The chronic no-effect level of NTA to the amphipods was 19 mg 1−1; in fathead minnows, it exceeded the highest exposure level (> 54 mg 1−1). 相似文献
9.
A. N. Spector Lay James Gibson Ashok K. Dutt William F. Hyde Paul B. Sherman Hans-Jurg Buttler Bernard Malamud Robert N. Anderson M. Penouil R. W. Keyes Lee R. McPheters William R. Eadington Kurt Puchinger Arthur E. Kartman Charles E. Starnes J. Barry Riddell Erick Sheppard Leon E. Zonn Craig Moore Neil S. Grigg K. Shimizu Daniel A. Griffith Noel D. Uri Micheal Ross Jack E. Adams Robert G. Fletcher Karol J. Krotki Peter D. Beaulieu Fred E. Case W. Edwin Derrick Barry D. Solomon Debnath Mookherjee John E. Keith Yuk Lee Andrew A. Dzurik W. W. Hall Jr. Lloyd W. Klemke Ted J. Adamczyk 《The Annals of Regional Science》1981,15(3):82-146
10.
A series of full-scale fire tests utilizing prototype “quick-response” sprinklers was conducted in a two-story residence in
Los Angeles, CA, and a mobile home in Charlotte, NC. A prime objective of the program was to test the performance of alternative
sprinkler designs to “control” the development of fire in single-family dwellings and mobile homes. Part of the mobile home
test series focused on a study of the comparative activation times of sprinklers and smoke detectors installed in the same
areas under a variety of test conditions. The results of that phase of the test program are given here.
National Fire Protection Association
REFERENCE: Cote, arthur E., “Field Test and Evaluation of Residential Sprinkler Systems”, Fire Technology, Vol. 20, No. 2,
May 1984, p. 41.
Mr. Cote is Assistant Vice President (Engineering & Technical Services) for the NFPA. He served as project manager for the
test series insofar as the NFPA had overall management responsibilities for the program. 相似文献