某大型超市火灾危险性评估研究

某大型超市具有人员活动集中、火灾荷栽密度较大以及疏散距离超长等特点,超出现有建筑防火规范要求,给判断是否安全带来不确定性。该文利用性能化设计方法研究了该超市在设定火灾条件下烟气填充以及人员疏散情况,并通过安全疏散时间判据来分析人员是否能够全部疏散。研究结果表明：在满足设定的火灾条件下,该超市的保护人员和财产的安全目标是可以达到的。     

Predication of Fhhh potential in PTA wastewater treatment

Ebis is the intelligent environmental biotechnological informatics software developed for judging the effectiveness of the microorganism strain in the industrial wastewater treatment system(IWTS) at the optimal status. The parameter, as the objective function for the judgment, is the minimum reactor volume ( Vmin ) calculated by Ebis for microorganism required in wastewater treatment. The rationality and the universality of Ebis were demonstrated in the domestic sewage treatment system(DSTS) with the data published in US Aand China at first, then Fhhh strain‘s potential for treating the purified terephthalic acid(PTA) was proved. It suggests that Ebis would be useful and universal for predicating the technique effectiveness in both DSTS and IWTS.     

变温环境下典型胶黏剂对光纤光栅传感器应变传递特性的影响

目的 验证粘贴式FBG传感器对宽温度环境的适应性。方法 通过高低温循环试验研究温度对传感性能的影响。对FBG传感器安装参数进行分析和优化设计,用353ND、UHU PLUS、ergo 5800和502等4种胶黏剂在铝合金表面粘贴安装FBG传感器,制成FBG测试样件。对测试样件进行高低温循环测试,测试试验前后FBG的传感性能,分析高低温循环对FBG传感性能的影响情况。结果 高低温循环后,FBG传感器中心波长产生了0.015～0.642 nm偏移,传感器灵敏度下降范围为0.563%～2.07%。结论 在实际选择FBG传感器胶黏剂时,需特别关注胶黏剂的温度适用范围参数,以减少胶黏剂温度适应性对测试结果的影响,提高测量精度。     

混凝土箱形截面考虑二阶效应的配筋图算法

箱形和工字形截面是工程中常用的截面形式,但按《混凝土结构设计规范》计算此类截面的配筋公式繁多,还需事先判断,然后选择相应的计算公式,比如拉弯时,要判断拉力合力点是否在大小两侧钢筋之间,区分小偏拉或大偏拉;压弯时,要判断大小偏心,除此之外,还需判断中性轴是否在翼缘或在腹板内等.为了方便快速计算,本文不采用规范中的等效矩形...     

Impact of proposed changes in IESTI equations for short-term dietary exposure to pesticides from Australian and Codex perspective

ABSTRACT

In 2015 a scientific workshop was held in Geneva, where updating the four equations for estimating the short-term dietary exposure (International Estimated Short Term Intake, IESTI) to pesticides was suggested. The impact of these proposed changes on the exposure was studied by using residue data and large portion consumption data from Codex and Australia. For the Codex data, the exposure increased by a median factor of 2.5 per commodity when changing to the proposed IESTI equations. The increase in exposure was highest for bulked and blended food commodities (case 3 equations), followed by medium-sized food commodities (case 2a equations) and small- and large-sized food commodities (case 1 and case 2b equations). For the Australian data, out of 184 maximum residue limit (MRL) large portion combinations showing acute exposures below the acute reference dose (ARfD) with the current IESTI equations, 23 exceeded the ARfD with the proposed IESTI equations (12%). The percentage exceeding the ARfD was higher for the Australian MRL large portion combinations (12% of 184) than for those of Codex (1.3% of 8,366). However, the percentage MRL loss in the Australian dataset may not be representative of all pesticide MRLs since it concerns six pesticides only, specifically selected to elucidate the potential effects of the use of the proposed IESTI equations. For the Codex data, the increase in exposure using the proposed equations resulted in a small increased loss of 2.6% of the 1,110 MRLs estimated by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR): 1.4% of the MRLs were already not acceptable with the current equations, 4.0% of the MRLs were not acceptable with the newly proposed equations. Our study revealed that case 3 commodities may be impacted more by the proposed changes than other commodities. This substantiates one of the conclusions of the Geneva workshop to gather information on bulking and blending practices in order to refine MRL setting and dietary risk assessment for case 3 commodities where possible.     

Integrating Large Wood Jams into Hydraulic Models: Evaluating a Porous Plate Modeling Method

Large wood (LW) jams are key riverine habitat features that affect hydraulic processes and aquatic habitat. The hydraulic influence of LW jams is poorly understood due to the complexity of fluid dynamics around irregular, porous structures. Here we validated a method for two‐dimensional hydraulic modeling of porous LW jams using the open‐source modeling software Delft3D‐FLOW. We sampled 19 LW jams at three reaches across the Columbia River Basin in the United States. We used computer‐generated porous plates to represent LW jams in the modeling software and calibrated our modeling method by comparing model outputs to measured depths and velocities at validation points. We found that modeling outputs are error‐prone when LW jams are not represented. By representing LW jams as porous plates we reduced average velocity root mean square error (RMSE) values (i.e., improved model accuracy) by 42.8% and reduced average depth RMSE values by 5.2%. These differences impacted habitat suitability index modeling. We found a 15.1% increase in weighted useable area for juvenile steelhead at one test site when LW jams were simulated vs. when they were ignored. We investigated patterns in average RMSE improvements with varying jam size, bankfull obstruction, porosity, and structure type, and river complexity. We also identified research gaps related to field estimation of LW jam porosity and porous structure modeling methods.     

基于实验与仿真的三维水下气体泄漏预测与安全评估研究

水下气体羽流特性是海底气体泄漏风险评估的重要基础。为准确预测水下气体羽流行为,基于计算流体动力学(CFD)方法,建立1种考虑气体卷吸湍流特性的三维水下气体羽流数值预测模型;采用欧拉-欧拉流体体积模型捕捉气液作用界面,以大涡模拟(LES)方式预测羽流上浮及卷吸过程中的湍流特性,从而实现对水下气体羽流行为的预测;搭建小尺度实验平台,对比仿真与实验条件下的气体羽流形态,验证数值模型的可行性及预测精度;应用建立的数值模型对工程条件下的水下气体泄漏事故进行预测和评估,以某浅层气井喷事故为例,评估水下气体羽流上浮时间、海面影响范围和涌流高度。结果表明:基于欧拉多相流与大涡模拟的数值模型对水下气体羽流预测结果与实验具有较好的吻合度,该模型能够较好捕捉羽流的湍流特性,可为水下气体泄漏羽流行为评估提供参考。     

大断面高铁隧道掘进爆破振动传播规律研究*

为研究隧道爆破掘进振动规律并合理控制爆破振动危害,对京张高铁大断面南口隧道爆破掘进过程进行实时监测,并对监测结果进行线性回归分析,求得3个监测方向的场地系数K和衰减系数α值以及爆破振动峰值速度衰减回归方程,通过FFT法计算出主振频率和爆破振动波的振动频率范围,利用ANSYS/LS-DYNA对爆破工程进行数值模拟。结果表明:喷锚支护和监测方向对爆破振动衰减回归分析影响较大;主振频率和爆破振动波的振动频率分布范围为50~300 Hz,无需考虑周边建筑共振情况,与周边古建筑和临近隧道的最小安全距离分别为147 m和12 m;数值模拟与实际结果对比发现二者振动峰值略有差别但整体趋势基本相同,证明建立模型的有效性。     

大型游乐设施运行状态测试系统及关键技术研究

系统分析游乐设施当前的测试水平,指出游乐设施运行状态测试是当前迫切需要解决的问题,并确定了加速度测试、速度测试、应力应变测试作为游乐设施运行状态测试系统的核心。结合游乐设施运行的特点,分别对以上3种核心测试技术从理论分析、设备选择、测试方法上进行了深入的研究。测试案例表明:基于以上技术测试的游乐设施运行状态测试系统是可行的,并为游乐设施检测提供了有力的技术支持。     

共基质和无机盐对原油降解菌株降解原油效果的影响

从大港油田石油污染土壤中分离筛选出1株原油降解菌X3,对原油的降解率达72．6％,经鉴定X3菌株属于假单胞菌属（Psedomonas）。利用生物摇床对X3菌株降解原油的实验发现,共代谢基质α-乳糖对X3菌株降解原油有促进作用,可使原油降解率提高到80．3％;而葡萄糖和蔗糖对X3菌株降解原油有抑制作用。Fe2＋对X3菌株的降解原油也有促进作用,在α-乳糖和Fe2＋的共同作用下,X3菌株对原油的降解率可达82．3％;K＋和Mg2＋对X3菌株降解原油则有抑制作用。在FeSO4质量浓度为0．2～0．3mg／L时,X3菌株对原油的降解率最高,FeSO4质量浓度继续增加,X3菌株对原油的降解率下降。