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961.
Fahhad Alharbi John D. Bass Abdelmajid Salhi Ahmed Alyamani Ho-Cheol Kim Robert D. Miller 《Renewable Energy》2011,36(10):2753-2758
Presented are the results of a comparative analysis to identify abundant, non-toxic binary materials with potential applicability for photovoltaics. Materials other than the conventional Si, CdTe, and Cu(In,Ga)Se2 (CIGS) are examined. The screening is based on the materials’ bulk properties and a set of environmental, physical, and chemical criteria. The screening process is detailed and the properties and applicability of the screened materials are discussed. 相似文献
962.
Use of Sb spray for improved performance of InAs/GaAs quantum dots for novel photovoltaic structures
Stephen P. Bremner Latha NatarajSylvain G. Cloutier Conan WeilandAnup Pancholi Robert Opila 《Solar Energy Materials & Solar Cells》2011,95(7):1665-1670
Photoluminescence output from InAs/GaAs quantum dots has been improved by a Sb treatment immediately prior to capping with GaAs. Spectra taken at 300 and 80 K show a significant increase in output intensity when the quantum dots are exposed for 15 s under a Sb flux of approximately 0.1 monolayers per second, but this improvement is lost when the Sb exposure is extended to 30 s. There is no significant shift in the emission energies between samples indicating strain relief due to the cap layer is not responsible for the improvement. Analysis of temperature dependent photoluminescence taken between 80 and 300 K show increased activation energies at lower temperatures when an Sb spray is used, suggesting passivation of deep defect levels. For the higher temperature activation energy, corresponding to carrier escape from the QD to the barrier, whilst a 15 s Sb spray gives a substantial increase, the longer 30 s Sb spray sees the activation energy decrease, a result deduced to be due to Sb segregation providing shallow defect levels. A band structure including a very thin GaAsSb layer adjacent to the quantum dots is used to explain these results, with the 30 s Sb spray leading to shallow Sb segregation related defects and a lower activation energy. Depth dependent X-ray photoelectron spectroscopy data support the band structure proposed to explain the photoluminescence results and also reveals the highest concentration of Sb at the sample surface suggesting a ‘floating layer’ of Sb during growth of the GaAs cap. Some of the implications of these results, for growth of quantum dot samples and for two novel solar cell proposals, the intermediate band and hot carrier solar cells, are discussed. 相似文献
963.
Practical aspects of implementing surfactant mass balance computation in finite elements models, where the model geometry
shape change is captured by utilizing the arbitrary Lagrange–Eulerian method are discussed briefly. The discussion and the
reported simulations are carried out in two-dimensional Cartesian coordinates. Two alternative approaches to formulating the
governing equation of surfactant mass balance for solving it computationally are presented and discussed. One of the approaches
is based on computing the boundary curvature and boundary tangential velocity, as well as their differentials on the boundary,
directly. The other approach is based on reformulating the governing equation in order to track the proportional rate of change
of local surface area. As a conclusion, it is found that though both of the presented approaches can be configured to perform
adequately in terms of surfactant mass conservation, surface differentials that are necessary to compute the surface curvature
and surface tangential velocity in the first one of the methods evoke numerical oscillations near those points of the boundary
where it is not smooth. The text is accompanied by example simulations and figures. 相似文献
964.
Vincent Lemiale Yuri Estrin Hyoung Seop Kim Robert O’Donnell 《Metallurgical and Materials Transactions A》2011,42(10):3006-3012
Grain refinement by plastic deformation is becoming increasingly popular as a way of producing metals with improved properties,
such as higher mechanical strength. Surface treatment techniques in which a metallic substrate is bombarded with metallic
particles can generate nanocrystalline layers in the impact zone. Understanding the physical mechanisms underlying this grain
refinement is crucial for achieving an improvement of existing experimental processes. In this article, we propose a numerical
framework combining finite element (FE) simulations with a dislocation-based material model to predict the evolution of the
microstructure under particle impact. A single particle normally impacting on a metallic substrate was simulated at different
initial velocities. The simulations were compared with previously reported numerical and experimental data. The results indicate
that our model accurately captures the grain refinement in the impact zone for a broad range of velocities. This approach
provides valuable information on the formation of nanocrystalline layers in both the substrate and the impacting particle.
Its potential applications include processes involving surface treatment by high velocity particles, such as shot peening,
surface mechanical attrition treatment, kinetic metallization, cold spray, etc. 相似文献
965.
Synthesis and properties of cross‐linked polymers from epoxidized rubber seed oil and triethylenetetramine 下载免费PDF全文
Muhammad Yusuf Abduh Muhammad Iqbal Francesco Picchioni Robert Manurung Hero J. Heeres 《应用聚合物科学杂志》2015,132(40)
A series of epoxidized oils were prepared from rubber seed, soybean, jatropha, palm, and coconut oils. The epoxy content varied from 0.03 to 7.4 wt %, in accordance with the degree of unsaturation of the oils (lowest for coconut, highest for rubber seed oil). Bulk polymerization/curing of the epoxidized oils with triethylenetetramine (in the absence of a catalyst) was carried out in a batch setup (1 : 1 molar ratio of epoxide to primary amine groups, 100°C, 100 rpm, 30 min) followed by casting of the mixture in a steel mold (180°C, 200 bar, 21 h) and this resulted in cross‐linked resins. The effect of relevant pressing conditions such as time, temperature, pressure, and molar ratio of the epoxide and primary amine groups was investigated and modeled using multivariable nonlinear regression. Good agreement between experimental data and model were obtained. The rubber seed oil‐derived polymer has a Tg of 11.1°C, a tensile strength of 1.72 MPa, and strain at break of 182%. These values are slightly higher than for commercial epoxidized soybean oil (Tg of 6.9°C, tensile strength of 1.11 MPa, and strain at break of 145.7%). However, the comparison highlights the potential for these novel resins to be used at industrial/commercial level. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42591. 相似文献
966.
Investment optimization model for freshwater acquisition and wastewater handling in shale gas production 下载免费PDF全文
Linlin Yang Ignacio E. Grossmann Meagan S. Mauter Robert M. Dilmore 《American Institute of Chemical Engineers》2015,61(6):1770-1782
Major challenges of water use in the drilling and fracturing process in shale gas production are large volumes required in a short‐period of time and the nonsteady nature of wastewater treatment. A new mixed‐integer linear programming (MILP) model for optimizing capital investment decisions for water use for shale gas production through a discrete‐time representation of the State‐Task Network is presented. The objective is to minimize the capital cost of impoundment, piping, and treatment facility, and operating cost including freshwater, pumping, and treatment. The goal is to determine the location and capacity of impoundment, the type of piping, treatment facility locations and removal capability, freshwater sources, as well as the frac schedule. In addition, the impact of several factors such as limiting truck hauling and increasing flowback volume on the solution is examined. A case study is optimized to illustrate the application of the proposed formulation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1770–1782, 2015 相似文献
967.
968.
Christine M. Wickens Evelyn Vingilis Robert E. Mann Patricia Erickson Maggie E. Toplak Nathan J. Kolla Jane Seeley Anca R. Ialomiteanu Gina Stoduto Gabriela Ilie 《Accident; analysis and prevention》2015
Background
Despite limited empirical investigation, existing scientific literature suggests that individuals with a history or current diagnosis of conduct disorder (CD) may be more likely to demonstrate reckless and aggressive driving. Much of the limited research in this field examines the impact of childhood CD on driver behaviour and collision risk in young adults. Few if any, studies assess the impact of this disorder on driver behaviour beyond age 21 years. The current research is a population-based study of the impact of CD symptoms during childhood on the risk of engaging in driver aggression during adulthood.Methods
Data are based on telephone interviews with 5230 respondents who reported having driven in the past year. Data are derived from the 2011–2013 cycles of the CAMH Monitor, an ongoing cross-sectional survey of adults in Ontario, Canada aged 18 years and older. A binary logistic regression analysis of self-reported driver aggression in the previous 12 months was conducted, consisting of measures of demographic characteristics, driving exposure, problem substance use, alcohol- and drug-impaired driving, symptoms of attention deficit hyperactivity disorder, and childhood (before age 15) symptoms of CD.Results
When entered with demographic characteristics, driving exposure, and other potential confounders, childhood symptoms of CD increased the odds of reporting driver aggression more than two-fold (adjusted OR = 2.12). Exploratory analyses of the interaction between childhood symptoms of CD and age was not a significant predictor of driver aggression.Conclusions
Results suggest that symptoms of CD during childhood are associated with significantly increased odds of self-reported driver aggression during adulthood. Limitations and future directions of the research are discussed. 相似文献969.
970.
Jeffrey G. Tait Tamara Merckx Wenqi Li Cindy Wong Robert Gehlhaar David Cheyns Mathieu Turbiez Paul Heremans 《Advanced functional materials》2015,25(22):3393-3398
With lab‐scale solution‐processed thin film photovoltaic (TFPV) devices attaining market relevant efficiencies, the demand for environmentally friendly and scalable deposition techniques is increasing. Replacing toxic halogenated solvents is a priority for the industrialization of solution‐processed TFPV. In this work, a generalized five‐step process is presented for fabricating high‐performance devices from nonhalogenated inks. Resulting from this process, several new solvent systems are introduced based on thiophene, tetralin, 1,2,4‐trimethylbenzene, o‐xylene, and anisole for blade coating of three different diketopyrrolopyrrole‐based (pDPP5T‐2, pPDPP5T‐2S, and P390) bulk heterojunctions applied in organic photovoltaic devices. Devices based on pDPP5T‐2S and P390 attain 5.6% and 6.1% efficiency, respectively, greater than the efficiency either material reached when processed from the halogenated solvent system commonly used. These processes are implemented without post‐deposition annealing treatments or additives. The Hansen solubility parameters of the pDPP5T‐2 material are obtained, and are used, along with wettability data on a variety of substrates, to determine optimum solvent combinations and ratios for deposition. This generalized five‐step process results in new nonhalogenated solvent pathways for the scalable deposition of thin film photovoltaic materials. 相似文献