Multidimensional simulation of earth-contact heat transfer

A numerical investigation of earth-contact heat transfer adjacent to an experimental structure is presented. In particular, a comparison is made between a two- and a three-dimensional simulation. The results are compared directly with data measured from a purpose-built full-scale experiment. Indirect methods of estimating thermal conductivity and volumetric heat capacity are described and employed. The results show reasonable correlation between the simulated and measured thermal responses. The three-dimensional simulation appears to provide an improved representation of the field problem. Some of the challenges associated with simulating a full-scale field problem are considered. The determination of the representative boundary and initial conditions is shown to be important.

Cet article présente l'analyse numérique d'un système de transfert thermique par contact avec la terre installé à proximité d'une structure expérimentale. On y compare, notamment, une simulation bidimensionnelle et une simulation tridimensionnelle. Les résultats sont comparés directement à des données mesurées dans le cas d'une expérience grandeur nature conçue spécifiquement dans ce but. L'auteur décrit les méthodes indirectes d'estimation de la conductivité thermique et de la capacité thermique volumétrique utilisées. Les résultats montrent une corrélation raisonnable entre les réponses simulées et les réponses thermiques mesurées. La simulation 3D semble être une représentation améliorée du problème de terrain. Certaines des difficultés associées à la simulation d'un problème de terrain à grande échelle sont prises en considération. La détermination de la limite de représentation et des conditions initiales est jugée importante.

Mots-clés: bâtiments, contact avec la terre, efficacité énergétique, mesures sur le terrain, transfert de chaleur, simulation     

Evaluating design strategies,performance and occupant satisfaction: a low carbon office refurbishment

Existing buildings present the best opportunity for reducing greenhouse gas emissions in developed economies, given that only 2–3% of the building stock is newly built each year. Insights from a post-occupancy evaluation of a large-scale refurbishment project of a head office building in Sydney, Australia, are presented to inform future refurbishment strategies. The study evaluates occupant satisfaction and energy performance, and elicits influencing factors arising from the design process and interventions, ongoing building management, and operational performance. Occupants returned a high level of satisfaction across the range of environmental variables for overall comfort, temperature, lighting, and air quality as well as perceived productivity and health. These outcomes highlight the importance of improving indoor environmental quality for occupants particularly through increased fresh air, daylight, glare control, access to views, and noise management. The positive results reinforce the value of an integrated and user-responsive approach that was adopted for building design, development, and management. The reduction in operational energy (in this project, coupled with carbon reduction) as a consequence of refurbishment and positive user feedback demonstrates the potential to future-proof existing buildings in the context of climate change.

Les bâtiments existants offrent la meilleure possibilité de réduction des émissions de gaz à effet de serre dans les économies développées, étant donné que les constructions neuves ne représentent chaque année que 2 à 3% du parc bâti. Les enseignements retirés d'une évaluation après occupation d'une opération de rénovation à grande échelle réalisée dans l'immeuble d'un siège social de Sydney, en Australie, sont présentés afin d'infléchir les futures stratégies en matière de rénovation. L'étude évalue la satisfaction des occupants et les performances énergétiques, et met au jour les facteurs d'influence qui découlent du processus de conception et des interventions réalisées, de la gestion en cours du bâtiment et des performances de fonctionnement. Les occupants ont exprimé un degré de satisfaction élevé sur l'ensemble des variables environnementales concernant le confort global, la température, l'éclairage et la qualité de l'air, aussi bien que la productivité et la santé telles qu'ils les ont perçues. Ces résultats mettent en évidence le fait qu'il est important d'améliorer la qualité environnementale intérieure pour les occupants, tout particulièrement en apportant davantage d'air frais et de lumière du jour, un plus grand contrôle de l'éblouissement, un accès accru à des panoramas et une gestion renforcée du bruit. Ces résultats positifs renforcent l'utilité d'une approche intégrée et sensible aux besoins des utilisateurs, telle qu'elle a été adoptée pour concevoir, aménager et gérer ce bâtiment. La réduction de l'énergie de fonctionnement (dans cette opération, conjointement avec la réduction du carbone) en conséquence de la rénovation et du feedback positif des utilisateurs démontre le potentiel de cette approche pour permettre aux bâtiments existants de bien affronter l'avenir dans le contexte du changement climatique.

Mots clés: adaptation, changement climatique, confort, énergie, qualité environnementale intérieure, conception intégrée, occupants, évaluation après occupation, rénovation     

向“羁绊”说不

无论是在八十年代末期以Van Berkel&Bos Architectuurbureau名义运营或当前发展成为基于互联网进行知识交流和整合的开源平台,UNStudio一直提倡扩大对建筑师的授权并取消传统的办公等级制度.然而即使已发展成遍布全球的跨国协作网络,UNStudio已将其业务重心向东转移.现在,UNStudio将大部分工作都放在亚洲开展,过去经验显示这种趋势或许会毫无疑问且不可避免.UNStudio的每一项设计都被视为全球以及在全球化下国际建筑风格的展示,因此,UNStudio在亚洲市场的开发与其说是将具有异域风情的荷兰建筑移植到中国城市,不如说是培植地区特性与文化中性相结合的建筑.即便如此,如果UNStudio的设计方法本质上是对复杂性、互联性以及流动性的利用和展示的话,亚洲城市自然成为它的理想栖息地.     

ePAD: Earthquake Probability‐Based Automated Decision‐Making Framework for Earthquake Early Warning

The benefits and feasibility of earthquake early warning (EEW) are becoming more appreciated throughout the world. An EEW system detects an earthquake initiation based on a seismic sensor network and broadcasts a warning of the predicted location and magnitude shortly before an earthquake hits a site. The typical range of this lead time is very short, for example, from a few seconds up to a minute in California, which is a huge challenge for applications taking advantage of EEW. As a result, a robust automated decision process about whether to initiate a mitigation action is essential. Recent approaches based on cost–benefit analyses to properly treat the trade‐off between false alarms and missed alarms still face challenges in practical use, such as the exclusion of an important factor, lead time, in the real‐time decision process. In this study, we lay out an earthquake probability‐based automated decision‐making (ePAD) framework to give a general decision criterion based on basic decision theory and an existing cost–benefit analysis procedure. The concepts of decision function, decision contour, and surrogate model are utilized to achieve fast computation and to allow comparison between various decision criteria. A value of information model is developed to handle the lead time of EEW and its uncertainty to reduce the “false response rate” in the cost–benefit trade‐off. An illustrative example is presented to demonstrate how this framework allows more flexibility for users to adapt ePAD to correspond to their desired rational decision behavior.     

Analysis of Castor by ELISAs that Distinguish Ricin and Ricinus communis agglutinin (RCA)

To facilitate the analysis of castor (Ricinus communis L.) seed fractions and germplasm for ricin content, we investigated the use of enzyme‐linked immunosorbent assay (ELISA) methods to differentiate between ricin toxin and the related Ricinus communis agglutinin (RCA). Both proteins are based on a heterodimeric AB structure, with a common A chain. RCA comprises two dimers of A and B chains. Both proteins are found in the meal remaining after castor oil extraction and impede the commercial production of castor seed in the USA. We identified pairs of monoclonal antibodies (mAbs) that could distinguish between the structurally related proteins that share a common A chain. Antibody specificity was determined by ELISA and checked by immunoblotting. We found that mAb–mAb pairs afforded quantification of each castor protein, and that a mAb paired with a commercial polyclonal antibody provided detection of both with comparable sensitivity.     

Polyurethanes based on 2,2‐Dinitropropane‐1,3‐diol and 2,2‐bis(azidomethyl)propane‐1,3‐diol as potential energetic binders

On the base of 2,2‐bis(azidomethyl)propane‐1,3‐diol (BAMP) and 2,2‐dinitropropane‐1,3‐diol (DNPD) four different polyurethanes were synthesized in a polyaddition reaction using hexamethylene diisocyanate (HMDI) and diisocyanato ethane (DIE). The obtained prepolymers were mainly characterized using vibrational spectroscopy (IR) and elemental analysis. For determination of low and high temperature behavior, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used. Investigations concerning friction and impact sensitivities were carried out using a BAM drop hammer and friction tester. The energetic properties of the polymers were determined using bomb calorimetric measurements and calculated with the EXPLO5 V6.02 computer code. The obtained values were compared with the glycidyl azide polymer (GAP). The compounds turned out to be insensitive toward friction (>360 N) and less sensitive toward impact (40 J). The good physical stabilities, along with their sufficient thermal stability (170–210 °C) and moderate energetic properties renders these polymers into potential compounds for applications as binders in energetic formul;ations. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43991.     

Comparison of the Flow of Permanent and Condensable Gases through an Asymmetric Porous Membrane

Porous inorganic membranes are usually composed of several layers, which are asymmetric with respect to the flow direction. For permanent gases, investigations about the influence of the flow direction on the mass flux through an asymmetric ceramic membrane were previously performed and can be found in literature. Mass flow differences between the two flow directions were calculated. Here the flow of condensable gases, i.e., of vapors, through the same membrane is analyzed and it is shown that the mass flow might be up to 40 % larger in one direction than in the other direction.     

Near‐Infrared Intraoperative Chemiluminescence Imaging

Intraoperative imaging technologies recently entered the operating room, and their implementation is revolutionizing how physicians plan, monitor, and perform surgical interventions. In this work, we present a novel surgical imaging reporter system: intraoperative chemiluminescence imaging (ICI). To this end, we have leveraged the ability of a chemiluminescent metal complex to generate near‐infrared light upon exposure to an aqueous solution of Ce⁴⁺ in the presence of reducing tissue or blood components. An optical camera spatially resolves the resulting photon flux. We describe the construction and application of a prototype imaging setup, which achieves a detection limit as low as 6.9 pmol cm^?2 of the transition‐metal‐based ICI agent. As a proof of concept, we use ICI for the in vivo detection of our transition metal tracer following both systemic and subdermal injections. The very high signal‐to‐noise ratios make ICI an interesting candidate for the development of new intraoperative imaging technologies.     

Poly dimethylsiloxane/carbon nanofiber nanocomposites: fabrication and characterization of electrical and thermal properties

This article presents the fabrication and characterization of poly dimethylsiloxane/carbon nanofiber (CNF)-based nanocomposites. Although silica and carbon nanoparticles have been traditionally used to reinforce mechanical properties in PDMS matrix nanocomposites, this article focuses on understanding their impacts on electrical and thermal properties. By adjusting both the silica and CNF concentrations, 12 different nanocomposite formulations were studied, and the thermal and electrical properties of these materials were experimentally characterized. The developed nanocomposites were prepared using a solvent-assisted method providing uniform dispersion of the CNFs in the polymer matrix. Scanning electron microscopy was employed to determine the dispersion of the CNFs at different length scales. The thermal properties, such as thermal stability and thermal diffusivity, of the developed nanocomposites were studied using thermogravimetirc and laser flash techniques. Furthermore, the electrical volume conductivity of each type of nanocomposite was tested using the four-probe method to eliminate the effects of contact electrical resistance during measurement. Experimental results showed that both CNFs and silica were able to impact on the overall properties of the synthesized PDMS/CNF nanocomposites. The developed nanocomposites have the potential to be applied to the development of new load sensors in the future.