环境工程中大气污染危害与治理方案的解读

当前,随着我国社会工业化水平的不断提升,工业化企业在市场中得到了快速的发展.但是,由于工业化企业在生产的过程中,产生了大量的污染气体,严重破坏了我国大气环境质量,导致我国大气环境污染问题越加的严重,许多大城市中经常会出现雾霾等环境问题,严重影响到了人们的生活质量,甚至对社会的稳定发展也造成了严重的影响.大气污染问题对人...     

纺织行业中多环芳烃的危害及其替代研究

多环芳烃(PAHs)一般存在于煤、煤焦油和原油等自然物质中,而一些人为因素也会使环境中产生多环芳烃化合物。在纺织行业中,多环芳烃主要用作生产染料的基本原料,同时也广泛存在于橡胶制品和塑料制品中。由于PAHs具有潜在的毒性和致癌、致畸变性,并且它可以在生物体内累积和在食物链中传递,因此给环境和人类健康带来极大的威胁。PAHs对环境的污染已经引起了全世界的关注,很多国家均对消费品中PAHs的含量进行了严格的限制。主要介绍了PAHs的危害、法规要求及其在纺织行业中替代品的研究动态。     

Silage review: Animal and human health risks from silage

Silage may contain several agents that are potentially hazardous to animal health, the safety of milk or other animal food products, or both. This paper reviews published literature about microbial hazards, plant toxins, and chemical hazards. Microbial hazards include Clostridium botulinum, Bacillus cereus, Listeria monocytogenes, Shiga toxin-producing Escherichia coli, Mycobacterium bovis, and various mold species. High concentrations of C. botulinum in silage have been associated with cattle botulism. A high initial concentration of C. botulinum spores in forage in combination with poor silage fermentation conditions can promote the growth of C. botulinum in silage. The elevated pH level that is generally associated with aerobic deterioration of silage is a major factor influencing concentrations of L. monocytogenes, Shiga toxin-producing E. coli, and molds in silage and may also encourage survival and growth of M. bovis, the bacterium that causes bovine tuberculosis. Soil is a major source of B. cereus spores in silage; growth of this bacterium in silage appears to be limited. Hazards from plant toxins include pyrrolizidine, tropane and tropolone alkaloids, phytoestrogens, prussic acid, and mimosine, compounds that exist naturally in certain plant species that may contaminate forages at harvesting. Another group of toxins belonging to this category are ergot alkaloids, which are produced by endophytic fungal species in forages such as tall fescue grass, sorghum, and ryegrass. Varying effects of ensiling on the degradation of these plant toxins have been reported. Chemical hazards include nitrate, nitrite, and toxic oxide gases of nitrogen produced from nitrate and high levels of butyric acid, biogenic amines, and ammonia. Chemical and microbiological hazards are associated with poorly fermented silages, which can be avoided by using proper silage-making practices and creating conditions that promote a rapid and sufficient reduction of the silage pH and prevent aerobic deterioration.     

Organic Food: Buying More Safety or Just Peace of Mind? A Critical Review of the Literature

Consumer concern over the quality and safety of conventional food has intensified in recent years, and primarily drives the increasing demand for organically grown food, which is perceived as healthier and safer. Relevant scientific evidence, however, is scarce, while anecdotal reports abound. Although there is an urgent need for information related to health benefits and/or hazards of food products of both origins, generalized conclusions remain tentative in the absence of adequate comparative data. Organic fruits and vegetables can be expected to contain fewer agrochemical residues than conventionally grown alternatives; yet, the significance of this difference is questionable, inasmuch as actual levels of contamination in both types of food are generally well below acceptable limits. Also, some leafy, root, and tuber organic vegetables appear to have lower nitrate content compared with conventional ones, but whether or not dietary nitrate indeed constitutes a threat to human health is a matter of debate. On the other hand, no differences can be identified for environmental contaminants (e.g. cadmium and other heavy metals), which are likely to be present in food from both origins. With respect to other food hazards, such as endogenous plant toxins, biological pesticides and pathogenic microorganisms, available evidence is extremely limited preventing generalized statements. Also, results for mycotoxin contamination in cereal crops are variable and inconclusive; hence, no clear picture emerges. It is difficult, therefore, to weigh the risks, but what should be made clear is that 'organic' does not automatically equal 'safe.' Additional studies in this area of research are warranted. At our present state of knowledge, other factors rather than safety aspects seem to speak in favor of organic food.     

昌邑—大店一带活动断裂对地质灾害影响研究

为研究活动断裂对地质灾害的影响,选取华北板块鲁西地块与苏鲁造山带东界昌邑—大店断裂为研究对象,通过野外面积调查、构造剖面测量、工程地质样品分析测试、综合研究等手段,详细调查了区内活动构造的特征、地质灾害的发育特征,在此基础上讨论了活动断裂对地质灾害影响机制,认为受昌邑—大店构造的影响,地裂缝分布主要沿构造带分布,区内地...     

基于生态协调的景区崩塌地质灾害综合治理——以北京石门山景区为例

景区地质灾害不仅对自然景观和生态环境造成破坏,还严重威胁游客的生命安全。本文对北京石门山景区崩塌地质灾害特征进行介绍,对危岩体的规模、破坏模式和稳定性进行系统分析,结合景区位置、灾害规模和内部交通条件,对多种治理方法进行比选分析,通过采用上部清理危岩浮石、底部挡墙防护及避让的综合治理措施,最大程度地保护景区的自然景观、自然资源和游客人身安全,探索出与景区风景相协调且经济合理的治理方案,以期为类似景区地质灾害治理提供一定借鉴。     

FOX-7合成过程中硝化反应的热危险性

利用全自动反应量热器(RC1e)测定了1,1-二氨基-2,2-二硝基乙烯(FOX-7)合成过程中的硝化反应热释放速率及传热系数、比热容。结果表明硝化反应加料过程中的平均放热速率约为80 W,保温反应过程中的平均放热速率约为40 W,物料放热量为375.22 kJ·mol-1,理论绝热温升为483.8 K。采用差示扫描量热法(DSC)和热重-微商热重(TG-DTG)法分析了中间体2-(二硝基亚甲基)-5,5-二硝基嘧啶-4,6-二酮的热稳定性,其分解分为两个阶段,起始分解温度为30℃,第一阶段分解峰温为67.01℃,放热量为201.2 J·g-1;第二阶段分解峰温为87.15℃,放热量为1046.6 J·g-1,表明中间体的热稳定性较差。     

基于在线预警探测系统的反应热失控判据研究

反应热失控是引发反应风险的主要因素。确保在线预警探测系统的可靠灵敏性,根据系统反应状态及时准确的预测反应热失控,是预防反应事故又一道防线;失控判据是发展在线预警探测系统的瓶颈。系统概述了在线预警探测系统反应热失控判据及其应用现状,包括限值检查判据、热平衡判据、基于模型的方法、散度判据和神经网络方法,分析比较了各种方法的优缺点,并对在线预警系统判据未来的发展给与展望。     

斯蒂芬酸铅的静电危险性研究

为研究斯蒂芬酸铅(LTNR)的静电危险性,对其静电积累量和静电火花感度进行了全面的测试。选用不锈钢、铝、夹布胶木、导电胶皮和虫胶漆牛皮纸5 种滑槽,测试了不同滑槽长度和倾斜角度下LTNR 的下滑时间和静电积累量。计算出LTNR 与5 种滑槽的摩擦系数;研究了LTNR 的静电积累量随滑槽长度和倾斜角度的定量关系,分别拟合为线性方程和二次方程;研究了LTNR 的下滑速度和摩擦力对静电积累量的影响,并进行了二元线性回归,得出预估公式。此外,在不同的电容、电阻和极针间隙装置条件下,测试了LTNR 的静电火花感度。结果发现:测试条件对静电火花感度的测试结果影响较大,静电火花感度E50与极针间隙表现出正线性关系。     

程潮铁矿矿区地质灾害类型及其防治对策

本文阐述了程潮铁矿地质灾害发育种类、规模,初步分析了地质灾害的形成机制。并对矿区地质灾害的防治提出了初步方案。