夏热冬冷地区大型商业综合体的可持续策略探索——泛海城市广场(一期)绿色节能措施

随着我国的城镇化水平越来越高,城市商业综合体的规模和数量也迅猛发展,城市商业综合体的耗能、耗水、耗材以及对环境的影响问题日趋严峻,如何通过设计手段,把绿色、生态理念融入到整个设计过程,降低综合体的能耗,走持续化发展道路?该文试图通过泛海城市广场(一期)项目,结合LEED论证标准和绿色二星建筑标准,从可持续场地、节能与能源利用、建筑节水、节材与材料资源利用、室内环境质量五个方面探索绿色节能措施的节能效应及推广价值。     

Moisture permeability measurements under varying barometric pressure

The development of theories to describe combined heat and moisture transport through porous media has been the subject of a large volume of research over recent years. These theories are important for many areas of study including the investigation of the hygrothermal performance of building envelopes. This paper highlights the difficulties of obtaining separate values for the material vapour and liquid transfer coefficients, a knowledge of which is essential if combined heat and mass transport models are to be accurately solved. The determination of these individual coefficients is not possible using existing measurement methods which enable only a total moisture permeability to be measured with the liquid and vapour flux components combined. The possibility of carrying out measurements under varying barometric pressures to obtain this data is investigated and experimental results using particle board as a test material are reported and compared with results from a previously developed analytical approach. L'elaboration de theories permettant de decrire les transferts combines thermiques et d'humidite a travers des supports poreux a fait l'objet d'un grand nombre de recherches au fil des annees. Ces theories sont importantes pour de nombreux domaines d'etudes, notamment dans la recherche sur la tenue hygrothermique des enveloppes de construction. Ce document met en lumiere les difficultes a obtenir des valeurs independantes pour les coefficients de transfert de vapeur et de liquide dans les materiaux, dont la connaissance est essentielle, si l'on doit definir avec precision la combinaison des modeles de transfert de matiere et de transfert thermique. La determination de ces differents coefficients n'est pas possible avec les methodes de mesure actuellement disponibles, qui permettent seulement la mesure totale de la permeabilite de l'humidite avec la combinaison des elements de flux de vapeur et de liquide. On etudie la possibilite d'effectuer des mesures sous des pressions barometriques variables pour obtenir ces donnees et on enregistre les resultats en utilisant un panneau d'agglomere comme materiau d'essai, ces resultats etant compares a ceux extraits d'une precedente analyse.     

Non‐Conventional Electrochemical Techniques for Assembly of Electrodes on Glassy Carbon‐Like PPF Materials and Their Use in a Glucose Microfluidic Fuel‐Cell

This paper addresses the electrochemical growth of PtAg and Au nanoparticles on pyrolyzed photoresist films (PPFs). The PtAg/PPF electrode was evaluated toward oxygen reduction reaction (ORR) in the absence and presence of glucose; meanwhile the electrocatalytic activity of Au/PPF was investigated for the glucose electrooxidation reaction (GOR) in 0.3 M KOH in the absence and presence of air as an oxygen source. The results obtained using the electrochemical studies showed that the PtAg/PPF electrode exhibited tolerance toward the ORR in the presence of low glucose concentrations. Moreover, Au/PPF showed good affinity toward glucose oxidation at high concentrations (50 and 100 mM) in the presence of oxygen instead further oxidations of glucose by‐products. Both electrocatalysts were evaluated as the cathode (PtAg/PPF) and the anode (Au/PPF) in a glucose microfluidic fuel cell (G‐μFC) constructed using a UV‐lithography technique and several sheets of different polymeric materials. The G‐μFC was tested using 100 mM glucose with 0.3 M KOH as electrolyte in the absence of an external source of nitrogen or oxygen as the fuel at zero flow rate; this cell reached a maximum power density of 0.085 mW cm⁻² using a low Pt loading (approximately 20% of weight percentage) mixed with non‐noble materials, such as Ag.     

Modeling and Parametric Study of a Single Solid Oxide Fuel Cell by Finite Element Method

A 2D isothermal axisymmetric model of an anode‐supported solid oxide fuel cell has been developed. The model, which is based on finite element approach, comprises electronic and ionic charge balance, Butler–Volmer charge transfer kinetic, flow distribution and gas phase mass balance in both channels and porous electrodes. The model has been validated using available experimental data coming from a single anode‐supported cell comprising Ni–YSZ/YSZ/LSM–YSZ as anode, electrolyte and cathode, respectively. Hydrogen and steam were used as fuel inlet and air as an oxidant. The validation has been carried out at 1 atm, 1,500 ml min^–1 air flow rate and three different operating conditions of temperature and fuel flow rate: 1,073 K and 400 ml min^–1, 1,073 K and 500 ml min^–1, and 1,003 K and 400 ml min^–1. The polarization and power density versus current density curves show a good agreement with the experimental data. A parametric analysis has been carried out to highlight which parameters have main effect on the overall cell performance as measured by polarization curve, especially focusing on the influence of two geometrical characteristics, temperature and some effective material properties.     

Effect of Composition and Physical Properties of Silicon Nitride on Rolling Wear and Fatigue Performance

The improved performance of silicon nitride components over all-steel bearings in several applications has been demonstrated. However, the effects of grain size, intergranular phase composition, fracture toughness, and hardness on rolling wear and fatigue performance are not completely understood. Three commercial bearing materials were tested under standard conditions and their physical properties were obtained. Wear and fatigue properties were compared to physical properties and material composition. It was found that a high fracture toughness is not required for high fatigue life and wear resistance. Total wear and fatigue life of the assembly must be considered, in addition to performance of the ceramic material alone, for specific applications. Grain boundary composition did not appear to affect the wear mechanism of these hot-isostatically-pressed materials.     

节能与舒适 表皮材料的建筑性能表现及其设计应用

文章指出建筑能耗和环境舒适是建筑性能表现的主要方面之一,同时是绿色建筑概念所强调的重要内容。然而能耗最小化的节能设计和舒适最大化的设计却存在着一定的矛盾,如果将二者放置在建筑表皮的关联中,会发现表皮材料在这个矛盾关系中扮演着非常重要的角色。为了平衡这种矛盾关系,对建筑表皮材料的特征分析,应该综合考虑建筑位置、整体形态和朝向、建筑内部的功能布局、使用者活动空间、空间使用特征,甚至使用者的背景和行为模式等因素。文章通过案例分析研究,提出基于整体设计和基于使用者群体特征的两个思路,并阐述了其中的建筑表皮的材料特征及其设计应用。