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Abstract Urban renewal has become a key issue all through China's Transitional Period. The social, economic, political factors, and their correlations have been seriously considered. However, the effects of outdoor pedestrian thermal comfort and fluid ventilation effects as well as the residence living conditions in old city districts under urban reconstruction should, to some extent, be paid closer attention to. As an example, take an old city district in Wuhan where a comprehensive mathematical model describing the fluid flow and heat transfer characteristics has been presented. Considering the influences of ambient crosswind, solar radiation, and natural convection and radiation heat transfer, numerical analysis based on the original layout has been executed. By analyzing the temperature and velocity distributions of the old city district, a new planned layout has been presented in this research. By comparison, some basic rules have been advanced to achieve favorable thermal comfort and flow ventilation effects.

By means of the saturation shake-flask technique, the saturation solubility data of 3,3′-diaminodiphenyl sulfone in 14 monosolvents (n-propanol, N,N-dimethylformamide, methanol, ethanol, ethylene g...

This final report describes results achieved under a 20-month NREL subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE's long-range efficiency, reliability and manufacturing cost goals. The critical issues being addressed under this program are intended to provide the science and engineering basis for the development of viable commercial processes and to improve module performance. The generic research issues addressed are: (1) quantitative analysis of processing steps to provide information for efficient commercial-scale equipment design and operation; (2) device characterization relating the device performance to materials properties and process conditions; (3) development of alloy materials with different bandgaps to allow improved device structures for stability and compatibility with module design; (4) development and improved window/heterojunction layers and contacts to improve device performance and reliability; and (5) evaluation of cell stability with respect to device structure and module encapsulation.

Abstract Ammonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under oxidizing conditions the onset temperature for reaction was 850–875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH3 at 875 K. The products of reaction were N2 and N2O, while NO and NO2 concentrations were below the detection limit even under oxidizing conditions. The data were interpreted in terms of a detailed chemical kinetic model. The rate constant for the reaction of the important intermediate H2NO with O2 was determined from ab initio calculations to be 2.3 × 102 T2.994 exp(−9510 K/T) cm3 mol−1 s−1. The agreement between experimental results and model work was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3 ⟶ + OH NH2 ⟶ + HO 2 , NO 2 H2NO ⟶ + O 2 HNO ⟶ + O 2 NO ⟶ + NH 2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH radicals, and to NH2 + NO = N2 + H2O and NH2 + NO2 = N2O + H2O, which are the main chain-terminating steps.

The recent widespread mountain pine beetle (MPB) outbreak in the Southern Rocky Mountains presents an opportunity to investigate the relative influence of anthropogenic, biologic, and physical drivers that have shaped the spatiotemporal patterns of the outbreak. The aim of this study was to quantify the landscape-level drivers that explained the dynamic patterns of MPB mortality, and simulate areas with future potential MPB mortality under projected climate-change scenarios in Grand County, Colorado, USA. The outbreak patterns of MPB were characterized by analysis of a decade-long Landsat time-series stack, aided by automatic attribution of change detected by the Landsat-based Detection of Trends in Disturbance and Recovery algorithm (LandTrendr). The annual area of new MPB mortality was then related to a suite of anthropogenic, biologic, and physical predictor variables under a general linear model (GLM) framework. Data from years 2001–2005 were used to train the model and data from years 2006–2011 were retained for validation. After stepwise removal of non-significant predictors, the remaining predictors in the GLM indicated that neighborhood mortality, winter mean temperature anomaly, and residential housing density were positively associated with MPB mortality, whereas summer precipitation was negatively related. The final model had an average area under the curve (AUC) of a receiver operating characteristic plot value of 0.72 in predicting the annual area of new mortality for the independent validation years, and the mean deviation from the base maps in the MPB mortality areal estimates was around 5%. The extent of MPB mortality will likely expand under two climate-change scenarios (RCP 4.5 and 8.5) in Grand County, which implies that the impacts of MPB outbreaks on vegetation composition and structure, and ecosystem functioning are likely to increase in the future.

This report discusses the topic of periodic cruise trajectories for hypersonic flight. An extensive review of previous work associated with periodic cruise trajectories for subsonic, supersonic and hypersonic flight is presented to provide the background for this investigation. The primary objective of this report is to discuss why periodic cruise trajectories lead to near fuel-optimal trajectories from a heuristic, mathematical and computational perspective with air breathing propulsion. Results to date indicate that periodic achieves greater fuel savings by exchanging kinetic and potential energy more efficiently. The vehicle attempts to chatter back and forth between where the vehicle wants to fly for optimum aerodynamic and propulsive performance. Results from computational simulations are inconclusive and require further work to define appropriate interfaces for aerodynamic and propulsion data decks for input into the POST software. The notional design of a vehicle to fly periodic hypersonic cruise trajectories was improved by including concepts for engine installation, flight controls and by including considerations for off-design performance. This notional design provides a better starting point for more serious and complete vehicle design studies.

Biomass is a renewable energy source and environmentally friendly substitute for fossil fuels such as coal and petroleum products. Major limitation of biomass for successful energy application is its low bulk density, which makes it very difficult and costly to transport and handle. To overcome this limitation, biomass has to be densified. The commonly used technologies for densification of biomass are pelletization and briquetting. Briquetting offers many advantages at it can densify larger particles sizes of biomass at higher moisture contents. Briquetting is influenced by a number of feedstock and process variables such as moisture content, particle size distribution, and some operating variables such as temperature and densification pressure. In the present study, experiments were designed and conducted based on Box-Behnken design to produce briquettes using barley, wheat, canola and barley straws. A laboratory scale hydraulic briquette press was used for the present study. The experimental process variables and their levels used in the present study were pressure levels (7.5, 10, 12.5 MPa), three levels of temperature (90, 110, 130C), at three moisture content levels (9, 12, 15% w.b.), and three levels of particle size (19.1, 25.04, 31.75 mm). The quality variables studied includes moisture content, initial density and final briquette density after two weeks of storage, size distribution index and durability. The raw biomass was initially chopped and size reduced using a hammer mill. The ground biomass was conditioned at different moisture contents and was further densified using laboratory hydraulic press. For each treatment combination, ten briquettes were manufactured at a residence time of about 30 s after compression pressure setpoint was achieved. After compression, the initial dimensions and the final dimensions after 2 weeks of storage in controlled environment of all the samples were measured. Durability, dimensional stability, and moisture content tests were conducted after two weeks of storage of the briquettes produced. Initial results indicated that moisture content played a significant role on briquettes durability, stability, and density. Low moisture content of the straws (7-12%) gave more durable briquettes. Briquette density increased with increasing pressure depending on the moisture content value. The axial expansion was more significant than the lateral expansion, which in some cases tended to be nill depending on the material and operating variables. Further data analysis is in progress in order to understand the significance of the process variables based on ANOVA. Regression models were developed to predict the changes in quality of briquettes with respect of the process variables under study.

A particle size dependence for CO oxidation over rhodium nanoparticles of 1.9−11.3 nm has been investigated and determined to be modified by the existence of the capping agent poly(vinylpyrrolidone) (PVP). The particles were prepared using a polyol reduction procedure with PVP as the capping agent. The Rh nanoparticles were subsequently supported on SBA-15 during hydrothermal synthesis to produce Rh/SBA-15 supported catalysts for size-dependent catalytic studies. CO oxidation by O2 at 40 Torr CO and 100 Torr O2 was investigated over two series of Rh/SBA-15 catalysts: as-synthesized Rh/SBA-15 covering the full range of Rh sizes and the same set of catalysts after high temperature calcination and reduction. The turnover frequency at 443 K increases from 0.4 to 1.7 s−1 as the particle size decreases from 11.3 to 1.9 nm for the as-synthesized catalysts. After calcination and reduction, the turnover frequency is between 0.1 and 0.4 s−1 with no particle size dependence. The apparent activation energy for all ca...