土壤轻组有机质

轻组有机质主要是由不同分解程度的植物残体和一些微生物结构体组成,它的改变可以用来指示土壤肥力的变化.本文综述了轻组的分离方法、轻组的组成、种植和施肥对轻组的影响、轻组在土壤团聚体和土壤剖面中的分布以及轻组的季节性变化.     

整装反应器无反应条件下的传热

研究整装反应器在反应点火之前的传热行为以及反应器参数对基体热响应的影响。建立了起燃阶段反应器的传热模型,通过数值计算,分析和讨论了固相轴向热传导性能及各种设计参数对基体热响应的影响。比较了基体采用金属体或陶瓷体时热响应的不同。结果表明,当无量纲导热系数∧＜1时,固相轴向导热性能对基体热响应无明显影响,金属体具有好的热响应性能,参数分析有助于反应器的设计和建模。     

偏心不耦合装药爆炸应力场研究及应用

中深孔光面爆破或预裂爆破质量对永久边坡的长期稳定性与安全性至关重要。利用偏心不耦合装药爆炸应力场的全息动光弹研究成果,对传统不耦合装药结构进行了改进,使高边坡光面爆破或预裂爆破效果得到明显改善,减少了因爆破效果不佳而造成悬、浮石滑落的事故隐患。并在实践中取得了一些有益的经验,可供同仁借鉴。     

噪声主观反应模糊隶属函数的AHP计算方法

根据模糊数学层次分析法(AHP)的原理,构造判断矩阵,针对不同的环境功能区域,定量计算各主观烦恼度表述等级的隶属度,求出了相应环境下的模糊隶属函数,并运用于噪声主观烦恼反应阈值的计算.实例计算表明,对不同环境建立不同的烦恼隶属函数,更符合人们对噪声主观反应所作表述的实际,计算得到的烦恼概率和噪声阈值更科学可信.     

动态气升式环流反应器对生物除磷的强化作用

采用模拟污水,通过厌氧-好氧交替过程研究了活性污泥生物除磷过程.在实验过程中,通过周期性通入空气和氮气的实验方法,采用气升式环流反应器和普通鼓泡塔进行对比,在研究反应器的传质性能的基础上,进一步对反应器内的活性污泥形态和生物除磷性能进行了观察和测定.实验表明,相对于普通鼓泡塔,动态气升式环流反应器对活性污泥的生物除磷过程有明显的强化作用,磷的去除率提高了30%.      

The role of migration and founder effect for the evolution of cooperation in a multilevel selection context

The idea that natural selection can be meaningfully applied at the group level may be more important than previously thought. This perspective, a modern version of group selection, is called multilevel selection. Multilevel selection theory could incorporate previous explanations for the evolution of cooperation including kin selection. There is general agreement that natural selection favors noncooperators over cooperators in the case of an unstructured population. Therefore, the evolution of cooperation by multilevel selection often requires positive assortment between cooperators and noncooperators. The question is how this positive assortment can arise in the ecological meaning. We constructed an individual-based model of multilevel selection and introduced migration and evolution. The results showed that positive assortment was generated especially when a migration strategy was adopted in which individuals respond specifically to bad environmental conditions. It was also shown that the founder effect in the evolutionary process could further facilitate positive assortment by working with migration. We analyzed assortment by using relatedness defined in group-structured populations. The fact that cooperation was achieved by such migration and by the founder effect highlights the importance of sensitiveness to the ecological environment and of fluctuations in group size, respectively.     

泰勒杆试验的动态本构模型确认应用研究

本文运用模型确认理论,对泰勒杆试验在材料动态本构关系确认性方面的应用进行研究。以Johnson-Cook模型描述的OFHC材料为例,采用试验和数值模拟相比较迭代的优化方法,结合灵敏度分析,提出了一种简捷的确认和确定动态本构关系参数的方法。     

真菌降解挥发性有机物动力学模型研究

真菌生物滤池对废气的净化过程,不涉及液膜扩散以及过渡区等问题,因此与传统的细菌生物滤池的净化过程不同．在对真菌生物滤池净化低浓度乙硫醇废气的过程机理进行研究的基础上,建立了真菌生物滤池处理挥发性有机化合物的动力学模型,分别推导出用以描述乙硫醇在生物膜内生化过程的方程式和用以描述气流方向乙硫醇浓度轴向变化的方程式,二者共同描述乙硫醇废气在真菌生物滤池中的传输与被生物分解的过程．通过对含不同浓度乙硫醇废气处理的试验验证,所建立的真菌降解乙硫醇模型的模拟结果与实测结果具有较好的一致性．     

基于响应面法的煤矿钻孔随钻超声成像仪器受力部件优化设计*

摘要:为研制适用于煤矿瓦斯抽采钻孔、满足施工强度要求的小尺寸随钻超声成像仪器，对随钻超声成像仪器的关键受力部位——超声探头安装孔进行优化设计，分析煤矿瓦斯抽采钻孔的一般规格，建立超声探头安装孔的三维模型，确定关键参数类型及其取值范围，采用极差分析法找到对受力部件强度影响较大的参数，基于响应面法开展有限元数值模拟，运用Box-Behnken设计方法得到超声探头安装孔关键参数与仪器受力部件性能指标的关系，优化受力部件关键参数的数值。结果表明:优化前最大的等效应力为138.6 MPa，优化后受力部件最大等效应力较优化前降低9.05%。结论验证了设计方法的有效性，为煤矿抽采钻孔随钻测井仪器的研制提供思路。     

Process Safety Management (PSM) for managing contractors in process plant

Accidents involving contractors continue to occur with regular frequency. By using the standard set within the PSM 29 CFR 1910.119(h) regulations, it has been identified that certain aspects of the way contractors do work are not up to the stipulated regulatory requirements especially regarding matters like not providing mandatory personal protective equipment (PPE) to the workers, not discussing hazards related to handling procedures with the workforce and improper control of non-routine activities during changes in shifts. The PSM 29 CFR 1910.119(h) regulations promulgated in 1992 provides standards that covered processes to obtain and evaluate data regarding contractors' health and safety programs as well as the contractors' performance evaluation. Many of the accidents involving contractors are direct result of poor training of contractors and/or poor control of the contracted work. Even though most organizations have their own contractor management systems, there are issues in meeting the requirements of PSM. The PSM standard only state “what to do” not “how to do it”. This is known as self-regulatory policy which depends on the industries understanding to interpret the standard that also contribute to this problem. This paper presents a structured and easy technique to plan and implement a practical and comprehensive contractors' management system in process industries that will comply with OSHA CFR 1910.119. A model has been developed based on this technique and its application has been tested in a pilot plant for compliance to PSM regulation. The model is beneficial to the process industries as any deficiencies in the PSM contractors' management program will be highlighted by the model which will then easily correct the identified deficiency so as to minimize and prevent catastrophic accidents.