Heat transfer blockage in small scale combustion of polymers

Flame heat transfer blockage occurs as fuel vapors,soot and products of combustion near a burning fuel surface block much of the heat feedbacks(including external radiative heat flux)to the fuel surface of a burning object.Blockage clearly affects burning rates and heat release rates of fires.This needs to be included when calculating flame heat transfer in fire growth models.An understanding of burning of materials in small scale fires is of broad and vital importance for predicting their burning performan...     

智慧城市始于智慧设计

在智慧城市设计的各个领域中,科技最受关注,而空间设计最不受关注。但从城市建设的角度来看,现实应该正好相反。成功的智慧城市首先需要从根本上保持大城市始终具有的基本特质,它们必须是可以反复记录人类生活复杂性和多样性的载体。当前城市中的智能化数字网络必不可少,也应该加以整合,但我们更应该重点关注卓越的实际城市场所营造。目前,多伦多可能是全球最受瞩目的智慧城市创意试验场,基于此,主要详细介绍Sasaki事务所在多伦多大都市区设计的2个案例研究。     

花园在前所未有的时代中的作用

由COVID-19引起的全球性危机向世界各地的城市施加着压力,要求人们重新思考城市的发展和运营方式。不仅研究了花园过去如何成为,并且在将来如何继续作为城市结构中的重要元素,而且讨论了花园在当今这一空前的历史时期中起到的重要作用,以及花园与城市绿地对公共健康的影响。倡导设计师应该以创造多重感官体验为目的来进行花园设计,以为人类健康带来更多裨益。还提出了具有宏观指导意义的花园建设列表,用以帮助城市规划师和设计师将其最初的设计理念和方法融入花园之中。     

未固结砂岩地震弹性性质的岩石物理模型表征研究

 未固结碎屑砂岩储层是国内外重要的油气储层类型之一。在地震勘探中通常使用Hertz Mindlin(HM)接触模型来计算未固结砂岩的等效弹性特征。由于未固结碎屑砂岩在结构上具有不规则排列特征,在弹性波作用下颗粒间的应变特征不满足H M接触模型的基本假设,造成该模型在使用中会得到明显偏高的剪切模量值。针对这些不足,本文给出了利用切向刚度校正因子C及组合参数R/R对HM接触模型进行修正的方法,以考虑颗粒间松弛作用及颗粒不规则性对该模型计算结果的影响。分选性是未固结碎屑砂岩重要的结构特征,利用对未固结碎屑砂岩样品实验测试结果定性分析了分选性变化对介质储集层物性特征及地震弹性特征的影响,并结合岩石物理相关理论建立了表征未固结砂岩分选性变化对地震弹性特征影响的地震岩石物理模型     

Transmission studies of Hendra virus (equine morbillivirus) in fruit bats, horses and cats

OBJECTIVE: To determine the infectivity and transmissibility of Hendra virus (HeV). DESIGN: A disease transmission study using fruit bats, horses and cats. PROCEDURE: Eight grey-headed fruit bats (Pteropus poliocephalus) were inoculated and housed in contact with three uninfected bats and two uninfected horses. In a second experiment, four horses were inoculated by subcutaneous injection and intranasal inoculation and housed in contact with three uninfected horses and six uninfected cats. In a third experiment, 12 cats were inoculated and housed in contact with three uninfected horses. Two surviving horses were inoculated at the conclusion of the third experiment: the first orally and the second by nasal swabbing. All animals were necropsied and examined by gross and microscopic pathological methods, immunoperoxidase to detect viral antigen in formalin-fixed tissues, virus isolation was attempted on tissues and SNT and ELISA methods were used to detect HeV-specific antibody. RESULTS: Clinical disease was not observed in the fruit bats, although six of eight inoculated bats developed antibody against HeV, and two of six developed vascular lesions which contained viral antigen. The in-contact bats and horses did not seroconvert. Three of four horses that were inoculated developed acute disease, but in-contact horses and cats were not infected. In the third experiment, one of three in-contact horses contracted disease. At the time of necropsy, high titres of HeV were detected in the kidneys of six acutely infected horses, in the urine of four horses and the mouth of two, but not in the nasal cavities or tracheas. CONCLUSIONS: Grey-headed fruit bats seroconvert and develop subclinical disease when inoculated with HeV. Horses can be infected by oronasal routes and can excrete HeV in urine and saliva. It is possible to transmit HeV from cats to horses. Transmission from P poliocephalus to horses could not be proven and neither could transmission from horses to horses or horses to cats. Under the experimental conditions of the study the virus is not highly contagious.     

An Approximation Algorithm for the Fault Tolerant Metric Facility Location Problem

We consider a fault tolerant version of the metric facility location problem in which every city, j, is required to be connected to r _j facilities. We give the first non-trivial approximation algorithm for this problem, having an approximation guarantee of 3 · H _k , where k is the maximum requirement and H _k is the kth harmonic number. Our algorithm is along the lines of [2] for the generalized Steiner network problem. It runs in phases, and each phase, using a generalization of the primal–dual algorithm of [5] for the metric facility location problem, reduces the maximum residual requirement by one.     

打造社区/创造康复场所

几百年来，许多文明都直观地利用花园提升人们的 幸福感。如今，大量的科学研究证实了与大自然互动对人类的 身心健康有诸多益处。与自然接触有助于恢复注意力，减轻压 力和敌意。设计康复花园时，参与式设计十分关键，在这个环 节，设计师向相关专家获取用户需求，深入了解那些有严重健 康问题的人所面临的挑战。案例研究展示了针对癌症患者、战 争伤员、心理疾病患者及临终老人创造的适宜环境所采用的原 则和设计方案。每个群体都有其独特需求，笔者、学生和社区 成员合作，设计了一系列温馨的康复花园。     

冷张减机在汽车工业中的应用

介绍了目前在冰箱管、汽车用刹车管、油管等小直径管中生产已普遍使用的冷张减工艺。这种工艺尤其用在焊管生产中，管机只生产一种规格的管子，经过冷张减生产中种小直径管，了小到４．７５ｍｍ。使用该工艺有许多优点，诸如，节省能源，没有辐射，收得率高。     

加速重离子辐射对水稻的生物学效应研究——Ⅰ.加速重离子及~(60)Coγ射线辐照水稻干种子的当代生物学效应

用高传能线密度(LET)的~(56)Fe(190keV/μ)、~(40)Ar(90keV/μ)离子束及低LET的~(60)Coγ射线(0.27keV/μ)照射水稻干种子,对当代幼苗生长、根尖微核细胞率和染色体畸变率的效应,进行了实验分析。结果表明:对比三种辐射源,微核细胞率与染色体畸变率均随处理剂量增加而增加,且呈线性关系。以幼苗的生长半抑制剂量(D_(50))为指标,三种电离辐射(~(56)Fe、~(40)Ar离子束和~(60)Coγ射线)的相对生物学效应(RBE)比值为6.3∶1.9∶1。以微核细胞率为指标,三者的RBE比较值为11∶4∶1。可见高LET的~(56)Fe和~(40)Ar比低LET的~(60)Co有较高的辐射生物学效应,尤其是在诱发细胞核染色体畸变和微核出现方面,高LET离子束有很高的效率。     

Adaptive Neuro-Fuzzy Modeling of Mechanical Behavior for Vertically Aligned Carbon Nanotube Turfs

Several characterization methods have been developed to investigate the mechanical and structural properties of vertically aligned carbon nanotubes (VACNTs).Establishing analytical models at nanoscale to interpret these properties is complicated due to the nonuniformity and irregularity in quality of as-grown samples.In this paper,we propose a new methodology to investigate the correlation between indentation resistance of multi-wall carbon nanotube (MWCNT) turfs,Raman spectra and the geometrical properties of the turf structure using adaptive neuro-fuzzy phenomenological modeling.This methodology yields a novel approach for modeling at the nanoscale by evaluating the effect of structural morphologies on nanomaterial properties using Raman spectroscopy.