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21.
The 1992 Framework Convention on Climate Change created the basic international architecture for addressing climate change. That treaty was negotiated at a time when the research literature examining emissions mitigation and the role of energy technology was relatively limited. In the two subsequent decades a great deal has been learned. The problem of stabilizing the concentration of greenhouse gases in the atmosphere has proved far more difficult than envisioned in 1992 and the role of technology appears even more important when emissions mitigation strategies are co-developed in the context of multiple competing ends. 相似文献
22.
Marshall Baker 《Quantum Information Processing》2014,13(9):2149-2151
23.
Hall Peter A.; Marshall John; Mercado Annalyn; Tkachuk Gregg 《Canadian Metallurgical Quarterly》2011,56(1):43
Background: Motor vehicle accidents (MVAs) are highly prevalent and can result in a complex interplay of physical injury, disability, and emotional distress. It has been suggested that the manner in which individuals cope with pain experienced after injury may determine how much recovery of function can be achieved. Only a limited number of studies have examined this process in the context of a rehabilitation program, and to date few studies have examined both functional and quality of life outcomes in MVA recovery in a tertiary level program as a function of coping style. Methods: A sample of 96 consecutive referrals to a tertiary-level multidisciplinary functional restoration program completed physical performance measures pre- and post-treatment, as well as a standardized self-report measure of quality of life (QOL) at the same time points and 6-month follow-up. Results: Findings suggested that improvements from pre- to post-treatment were evident on the 6-minute walk test, left and right grip strength, and most QOL measures. Increases in active coping during treatment were associated with pre- to post-treatment increases in QOL across most domains, and improvements in performance on the 6-minute walk test. Likewise, decreases in passive coping during the course of treatment were associated with improved performance on the 6-minute walk test, right-handed standing reach test, and most QOL indicators. Conclusion: Findings suggest that those who adopt an active approach (and avoid taking a passive approach) to rehabilitation following complex musculoskeletal injury benefit along both QOL and functional dimensions relative to those who do not. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
24.
Michael N. Rossol Tony Fast David B. Marshall Brian N. Cox Frank W. Zok 《Journal of the American Ceramic Society》2015,98(1):205-213
We present a methodology for characterizing and reconstructing in‐plane weave variability in textile composites. Surface topography of a partially processed C‐fiber/SiC matrix composite panel was measured using digital image correlation. The centroids of tow segments that appear periodically on the fabric surface were located by image analysis and used as fiducial markers. Stochastic deviations of the fiducial markers from the ideal periodic weave structure indicate geometrical variance. Fourier analysis shows that spatial wavelengths of the deviations range from the size of one unit cell to the dimensions of the entire panel. Long‐range deviations are attributed principally to fabric deformation after manufacture, during handling. Short‐range fluctuations, extracted by computing spatial derivatives of the positions of the fiducial markers, are attributed to variations in tow packing density that arises during weaving. A simple set of statistics for these deviations is presented and its use in generating stochastic virtual specimens is demonstrated. 相似文献
25.
Zvolensky Michael J.; Marshall Erin C.; Johnson Kirsten; Hogan Julianna; Bernstein Amit; Bonn-Miller Marcel O. 《Canadian Metallurgical Quarterly》2009,17(1):31
The present investigation examines anxiety sensitivity, distress tolerance, and fear reactivity to bodily sensations in relation to Coping and Conformity marijuana use motives among a sample of young adult marijuana users (n = 135; 46.7% women; Mage = 20.45, SD = 5.0). After controlling for current marijuana use frequency (past 30 days), daily cigarette smoking rate, average volume of alcohol used over the past year, negative affectivity, and other marijuana use motives, anxiety sensitivity was significantly and uniquely associated with Coping and Conformity motives for marijuana use. Distress tolerance evidenced significant and unique incremental relations to Coping motives, whereas fear reactivity to bodily sensations was unrelated to any marijuana use motive. These results provide novel information related to the role of emotional sensitivity and tolerance factors as they pertain to specific types of motives for marijuana use among young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
27.
Details of experimental studies of the electropolishing of a number of metals in 10% sulphamic acid- formamide solutions are given. Iron, cadmium, zinc and tin polished and etched well in this system. Copper and uranium also polished but remained unetched at low current densities. Molybdenum and tungsten were also studied. Satisfactory etching and polishing of these metals was not achieved. Dissolution efficiencies were determined for Fe, Cu, Sn, Cd, Zn and U. The anodic behaviour of tin was studied in more detail in order to correlate the electrochemical conditions with the nature of the metal surface produced. The purity of the formamide used had some effect upon the anodic polarization characteristics of tin inasmuch as the limiting current density region was not clearly defined and the change in potential was only ~0·5V whereas in purified solutions this was much more clearly defined and existed over a potential range of ~4V. There was no evidence that impurities in the formamide affected the nature of the tin surface produced in relation to the appropriate polarization curve. 相似文献
28.
J. K. Cochran W. L. Daloz P. E. Marshall 《JOM Journal of the Minerals, Metals and Materials Society》2011,63(12):44-49
Development of Mo composites based on the Mo-Si-B system has been demonstrated as a possible new route to achieving a high
temperature Mobased material. In this new system, the silicide phases are replaced directly with silica or other silicate
materials. These composites avoid the high ductile to brittle transition temperature observed for Mo-Si-B alloys by removing
the Si that exists in solid solution in Mo at equilibrium with its silicides. A variety of compositions is tested for room
temperature ductility and oxidation resistance. A system based upon Mo, Mo2B, and SrO·Al2O3·(SiO2)2 is shown to possess both ductility at 80 vol.% Mo and oxidation resistance at 60 vol.%. These composites can be produced
using a powder processing approach and fired to greater than 95% theoretical density with a desirable microstructure of isolated
boride and silicate phases within a ductile Mo matrix. 相似文献
29.
Adele H. Marshall Mariangela Zenga 《International Transactions in Operational Research》2009,16(2):213-226
Coxian phase-type distributions are a special type of Markov model that can be used to represent survival times in terms of phases through which an individual may progress until they eventually leave the system completely. Previous research has considered the Coxian phase-type distribution to be ideal in representing patient survival in hospital. However, problems exist in fitting the distributions. This paper investigates the problems that arise with the fitting process by simulating various Coxian phase-type models for the representation of patient survival and examining the estimated parameter values and eigenvalues obtained. The results indicate that numerical methods previously used for fitting the model parameters do not always converge. An alternative technique is therefore considered. All methods are influenced by the choice of initial parameter values. The investigation uses a data set of 1439 elderly patients and models their survival time, the length of time they spend in a UK hospital. 相似文献
30.
S. Fröhlich J. Redfern L. Petitpierre J.D. Marshall M. Power P.V. Grech 《Journal of Petroleum Geology》2010,33(1):3-18
This paper assesses the diagenetic history of potential fluvial hydrocarbon reservoir rocks deposited within incised valley systems of the Lower Carboniferous Marar Formation in western Libya. Outcrop data were collected in the Tinedhan Anticline, located at the southern margin of the Ghadames Basin. Four discrete intervals with channelized sandstones were identified in a section dominated by alternating offshore mudstones and shallow-marine clastics. The incised channels were cut during major sea-level lowstands, and filled by fluvial sandstone packages up to 50 m thick. Fifty-eight samples from four different localities, representing three lowstand systems tracts, were analysed to obtain a statistically meaningful mineralogical and compositional dataset. In addition to burial compaction, three main diagenetic events influenced the reservoir quality of the sandstones. Firstly, early eodiagenesis involved kaolinitization of plagioclase grains. This began before subsequent calcite cementation, probably as a result of flushing by meteoric pore-waters. The deformation of kaolinite during later compaction resulted in the formation of pseudomatrix which further reduced porosity and permeability. Kaolinite is commonly transformed to illite at temperatures above 140°C in the presence of K-feldspar. Although K-feldspar was recorded in the samples, no illite was observed, suggesting that the Lower Carboniferous strata in the study area were not buried in excess of approximately 3.5 km. The second diagenetic phase was the precipitation of calcite cement, present either dispersed throughout the sandbodies or as concretions up to 2 m across, in both cases reducing reservoir quality. The high intergranular volumes (IGV) of calcite-cemented sandstones (ranging between 35% and 40%) suggest that cementation occurred at burial depths of <500 m. Sandstones without calcite cement have lower IGV of between 17% and 25% as a result of mechanical and chemical compaction. Stable C and O isotope analysis of the calcite cement also supports precipitation at shallow burial depths, indicating a meteoric pore-water source for the calcite. The third and final diagenetic stage was partial chloritisation of kaolinite during meso-diagenesis. The elevated temperatures required for this transformation indicate burial to a minimum depth of approximately 2.5 km, which is consistent with the compaction data. Despite these diagenetic effects, the fluvial sandstones have an average porosity of 12%, with a range from 0.5% up to 25%. Permeability measurements on four sandstone samples indicate that the development of pseudomatrix did not reduce permeability significantly. 相似文献