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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.

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.

Graphene has been used as an electrically tunable material for switchable devices. A large area fabrication of Al-doped ZnO/Al2O3/graphene/Al2O3/gold/silicon device was enabled by a spin-processible hydrophilic mono-layer graphene oxide. The graphene was obtained directly from graphene oxide during the atomic layer deposition without other extra steps. A significant shift of Raman frequency up to 360 cm−1 was observed from graphene in the fabricated device, indicating a structural change in graphene. The absorption from the device was tunable with a negative voltage applied on the Al-doped ZnO side. The generated absorption change was sustainable when the voltage was off and erasable when a positive voltage was applied. The sustainability of tuned optical property in the graphene under investigation can lead to a design of device with less power consumption and many other applications.

China's economic boom in the last three decades has spurred increasing demand for transportation services and personal mobility. Consequently, vehicle population has grown rapidly since the early 1990s, especially in megacities such as Beijing, Guangzhou, and Tianjin. As a result, mobile sources have become more conspicuous contributors to urban air pollution in Chinese cities. Tianjin was our first focus city, and the study there took us about two years to complete. Building upon the experience and partnership generated through the Tianjin study, the research team carried out the Beijing study from fall 2007–fall 2008. Beijing was chosen to be our second focus city for several reasons: it has the largest local fleet and the highest percentage of the population owning vehicles among all Chinese cities, and it has suffered from severe air pollution, partially due to the ever-growing population of on-road vehicles.

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 The issues of fossil-fired energy shortage and global warming have aroused worldwide attention, and the renewable and sustainable energy sources, therefore, are playing an increasingly important role in future energy consumptions. Energy consumptions in buildings account for almost 40% of the primary energy use in the US. A novel research-based Z er o E nergy (ZOE) Lab as a validation testbed combining various kinds of renewable energies has been presented in this paper. The concept, unique features, and the operation performance by experiments have also been shown in detail. The results of the novel ZOE Lab can open up a good angle for the future development of zero energy buildings. After analyzing the operating data of the ZOE Lab, the energy consumption, energy generation, and energy allocation of the devices have been presented. A new HVAC system with higher performance is recommended to be used in the ZOE Lab to achieve an even lower energy consumption than the current use, as a necessary refinement.

AbstractWe describe applications of PV Optics to analyze the behavior of a metallic back-reflector on an a-Si solar cell. The calculated results from PV Optics agree well with the measured data on solar cells. Several unexpected results obtained from these calculations are qualitatively explained.

Abstract This work focused on a novel form-stable phase change material (FSPCM) for building energy saving. Capric acid (CA) and palmitic acid (PA) were selected to prepare binary eutectic. The CA-PA/wood flour (WF) composites with different mass ratios were prepared by the vacuum impregnation method. After the shape-stabilized properties were investigated, the results indicated that there were the good encapsulate capacity of WF to CA-PA eutectic and the slight effect of WF on the crystallization. Phase change wood plastic composites (WPCs) using CA-PA /WF composites as the latent heat storage medium and PVC as the matrix were prepared. The relations between mass ratios of CA-PA /WF composites and mechanical properties of WPCs were discussed. The results revealed that the WPCs with appropriate mass fraction of CA-PA eutectic had desired mechanical properties for practical applications. The prepared composites were examined by the scanning electron microscope (SEM), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) and accelerated thermal cycling test. SEM images showed that the WPC prepared by the CA-PA /WF composite with the mass ratio of 0.4:1(WPC0.4) was more compact and uniform, but as the amount of CA-PA eutectic increased, more gaps and cracks appeared. DSC results showed that the WPC0.8 melted at 22.03 °C with a latent heat of 28.16 J/g and froze at 20.06 °C with a latent heat of 29.77 J/g, which was more applicable to the thermal energy storage systems for buildings. FTIR results demonstrated that there was no chemical reaction between CA-PA eutectic and components in WPC. The prepared FSPCM exhibited excellent thermal stability for the building materials from the TG analysis. Furthermore, the results of accelerated thermal cycling test showed that the composite had a good thermal reliability after 500 thermal cycles.