大空间单跨门式刚架结构抗火性能影响因素的客观权重研究

火灾时的大空间单跨门式刚架结构抗火性能,受钢构件温升和结构整体抗火临界温度的影响.本文通过对无保护大空间建筑钢构件温升数据的统计分析,获得包含火源功率、建筑体积、钢构件截面形状系数的钢构件温升拟合公式;结合单跨门式刚架结构整体抗火临界温度数据的统计分析,获得包含荷载比、柱高和系数K的结构整体抗火临界温度拟合公式;通过分...     

Thermodynamics of interaction of lindane on silty loam and silty clay loam Indian soils

Abstract

Interaction of lindane with silty loam and silty clay loam soils was studied in batch tests at 23, 30 and 37° C. Sorption experiments were carried out at four concentrations and for varying time of contact upto 72 hours. This was followed by desorption studies. No desorption was observed. The sorption data was analysed using sorption equations and evaluating the thermodynamic parameters. The sorption was found to be predominantly entropic in nature and a combined effect of adsorption and chemisorption. The effect of organic matter and other chemical and mineralogical constituents of soils has also been discussed. The sorption with single application of lindane with the two soil types indicates that the insecticide is less likely to reach groundwater.     

SUBWATERSHED SPATIAL ANALYSIS TOOL: DISCRETIZATION OF A DISTRIBUTED HYDROLOGIC MODEL BY STATISTICAL CRITERIA1

ABSTRACT: Complex hydrologic models, designed for simulating larger watersheds, require a huge amount of input data. Most of these models use spatially distributed data as inputs. Spatial data can be aggregated or disaggregated for use as input to a model, which can impact model outputs. Although, it is efficient to minimize data redundancy by aggregating the spatial data, upscaling reduces the detail/resolution of input information and increases model uncertainty. On the other hand, a large number of model inputs with high degrees of disaggregation take more computer time and space to process. Hence, a balance between striving for a maximum level of aggregation and a minimum level of information loss has to be achieved. This study presents a definition of an appropriate level of discretization, derived by establishing a relationship between a model's efficiency and the number of subwater‐sheds modeled. An entropy based statistical approach/tool called Subwatershed Spatial Analysis Tool (SUSAT) was developed to find an objective choice of an appropriate level of discretization. The new approach/tool was applied to three watersheds, each representing different hydrologic conditions, using a hydrologic model. Coefficients of efficiency and entropy estimated at different levels of discretization were used to validate the success of the new approach.     

Evaluation of Material Biodegradability in Real Conditions–Development of a Burial Test and an Analysis Methodology Based on Numerical Vision

This work validated a burial protocol for in situ testing and presents a robust, repeatable and time-saving technique to measure degraded areas in the sample, i.e. an image analysis method. 1440 specimens of degraded samples have been compiled in a data base. To this end, twenty samples presenting different levels of biodegradability (i.e. PHBV/HV, PLA, PCL, PCL-Starch, paper, PE, PE-Starch) were buried at 4 different locations and then disinterred at 4, 6, 9, 12, 18, and 24-month intervals. The biodegradation levels of these samples were determined by computing weight and area loss. Weight loss was measured after careful cleaning, whereas area loss was quantified using image analysis. Image analysis gives reliable information on visual pollution while only requiring a rudimentary and thus quicker cleaning of the samples.     

可拓法评估煤矿瓦斯爆炸易发性

为了量化煤矿瓦斯爆炸的可能性,并为防治瓦斯爆炸提供量化指标,借鉴可拓学原理,对煤矿瓦斯爆炸易发性进行预评估。首先,详细阐述可拓学评估原理;接着,为了验证煤矿瓦斯爆炸易发性可拓评估的可行性,结合某一煤矿实例,比选煤矿瓦斯爆炸易发性的评价指标,并确定煤矿瓦斯爆炸易发性的分类标准,构建煤矿瓦斯爆炸易发性评估的经典域、节域和物元;然后,为了避免确定指标权重的人为主观因素的影响,提出用简单关联函数确定指标权重;最后,计算煤矿瓦斯爆炸易发性的关联函数值和关联度,确定瓦斯爆炸易发性的等级及其变量特征值。经计算,煤矿爆炸易发性的可拓评估结果为"很小"等级。同时,为了验证可拓评估结果的合理性,将其与模糊评估进行比较,两者所得评估结果相一致。从而表明:将可拓学应用于煤矿瓦斯爆炸易发性评估是合理可行的。     

区域洪涝灾害风险的模糊综合评价与预测

以广西1992~2006年洪涝灾情数据为基础,选取适当的评价指标,用基于遗传算法、特征值法和优化算法的投影寻踪法和层次分析法确定各评价指标的分类权重和排序权重,用优化算法进行综合得到组合权重,经过加权求和得出洪涝灾害的模糊综合评价,进而对15个评价对象进行了分类排序,其分类结果很好地反映了洪涝灾情的实际情况。在以上模糊综合评价结果的基础上,利用距离贴近度进一步计算和分析各个评价指标之间的贴近度,并由择近原则确定各个评价指标之间在洪涝灾害评价中的相关程度。同时,建立了基于改进的灰色GM(1,1)的时间响应式的灾变年份预测模型。     

石化生产装置安全现状模糊综合评价方法研究

根据石油化工生产装置安全评价存在的模糊性和随机性的特点,在建立涵盖安全管理、工艺过程、作业环境、人员素质、生产设备和安全教育等一级指标的安全现状综合评价指标体系的基础上,运用模糊数学综合评判理论,采用基于信息论中熵概念计算指标权重的方法,提出了安全现状二级模糊综合评价方法。在组织专家对评价指标打分和确定模糊等级的基础上,应用该方法对某顺丁橡胶生产装置安全现状进行了综合评价,得出其安全状况为“较好”;并分析了指标体系中一级指标的状况,为制定安全对策措施提供了指导。该方法对于提高石油化工生产装置安全现状综合评价的客观性和准确性具有理论意义和实用价值。     

船舶安全熵概念的提出及应用

船舶航行安全很大程度上取决于操作者对船舶航行过程中各种信息的把握,信息掌握的多少可作为衡量船舶安全的一个标准。把船舶航行链分为5种信息处理过程,利用信息熵的原理,提出船舶安全熵的概念,并建立了数学模型。根据船舶航行信息过程的具体因素,建立船舶航行安全评价指标体系;利用熵权法确定5种信息单元及其安全因素权重,对船舶航行的安全熵进行计算,可根据评价模型对船舶安全进行有效评价。利用渤海湾船舶M进行验证,其结果发现船员素质安全熵最大。船舶安全熵方法是对船舶安全评估的一种新探索。     

民航安全风险定量评价模型研究

在对民航风险评价的现状和常用的定量风险评价方法进行分析的基础上,建立民航安全风险定量评价模型。在计算风险的可能性时,不仅考虑了风险的历史发生概率,而且利用风险发生概率影响因素所发生的变化对风险的历史发生概率进行修正,从而得出在当前情况下风险的发生概率,并且首次提出指数型权重的概念;在计算风险的后果时,考虑风险的直接损失和间接损失,并通过计算多种可能后果的期望的形式,综合考虑多种可能的后果情况;通过上述的可能性和严重性从而达到对安全风险进行定量评价的目的。最后,给出了一个算例,其结果表明该模型具有很强的实用性。     

基于熵权理论的室内环境评价

以室内环境的空气品质以及声、光、热环境为研究对象,根据实测数据,建立不满意百分比指标PD(predicteddissatisfied),基于熵权理论对整个室内环境进行评价。在多因素的室内环境评价过程中,该方法在以实测数据确定评价指标的相对重要程度后,根据各评价对象之间某些评价指标重要度的差异,自动调节各种差异对评价过程的影响,合理的优化了评价过程。以某小区6户人家家庭环境的物理、化学因素测试的数据进行综合评价,其结果与实际情况相吻合。说明该方法所得到的评价结果具有说服力。