综合应急救援能力描述理论架构及提升内容研究

基于代数这一数学工具,该文创新建立综合应急救援能力描述理论架构,包括面向自然灾害、事故灾难、公共卫生、社会安全等灾种建立的救援灾害轴,面向村、社区、街道(镇)、区(县、市)、市、省等区域建立的救援区域轴,面向准备、响应、处置、保障、善后等时间建立的救援时间轴,由此构成综合应急救援能力描述三维坐标系;在此基础上,抽象出应...     

Study on the damage statistical strength criterion of backfill with crack under thermo-mechanical coupling

ABSTRACT

Aiming at backfill with crack under the thermo-mechanical (TM) coupling, the concepts of crack macro-damage, loading meso-damage, thermal meso-damage, and total damage of backfill were proposed. Based on the statistical damage theory, considering the coupling effects of temperature, load and initial crack, a damage evolution model of backfill with crack under TM coupling effects was established. Based on this, the strength criterion of backfill with crack considering the effects of thermal and mechanical coupling was constructed by multivariate function full differential method. The research shows that: (1) The theoretical curves of damage evolution model and strength criterion of backfill with crack under TM coupling are in good agreement with the test curves, which verifies the rationality of the model. (2) The initial thermal damage decreases first and then increases with increasing temperature, reaches a minimum value at 40°C, and generally shows a “V” -shaped distribution law. The coupling effect of temperature and crack aggravates the total damage of the backfill. (3) The strength criterion can reflect the relationship between the stress and strain of each limit state and the parameters of backfill with crack under different temperature conditions and can provide a certain reference for the evaluation of the stability of backfill with geological defects such as joints and crack in deep high temperature mines.     

Comparison of molecular transformation of dissolved organic matter in vermicomposting and thermophilic composting by ESI-FT-ICR-MS

Environmental Science and Pollution Research - The aim of this study was to investigate the effects of vermicomposting (VC) and thermophilic composting (TC) on the molecular transformation of...     

Quantitative analysis of the relationship between land use and urbanization development in typical arid areas

Environmental Science and Pollution Research - As the most sensitive and typical oasis city in the arid region of China, Jiayuguan, the role of land use change and urbanization in this region is...     

Assessing deposition levels of 55Fe, 60Co and 63Ni in the Ignalina NPP environment

Two RBMK-1500 reactor units operated in Lithuania in the 1987-2004 period (one of them was stopped for decommissioning in 2004). This study presents a preliminary investigation of surface deposition density levels of ⁵⁵Fe and ⁶³Ni in moss samples collected in the close vicinity of the Ignalina NPP. Non-destructive analysis by the HPGe gamma-spectrometry was followed by radiochemical separation. Radiochemical analysis was based on anion-exchange and extraction chromatography. ⁵⁵Fe and ⁶³Ni activities were measured by liquid scintillation counting (LSC). The results indicate that the deposition values of ⁵⁵Fe are generally higher than those of ⁶⁰Co and ⁶³Ni.     

Biohydrogen production from dairy manures with acidification pretreatment by anaerobic fermentation

Background, aim, and scope  

Hydrogen is a clean and efficient energy source and has been deemed as one of the most promising carriers of new energy for the future. From an engineering point of view, producing hydrogen by mixed cultures is generally preferred because of lower cost, ease of control, and the possible use of organic waste as feedstock. The biological hydrogen production has been intensively studied in recent decades. So far, most investigates of biohydrogen production are still confined to using pure carbohydrates and carbohydrate-rich wastewater. Nowadays, the large amounts of livestock manure, which come from cattle feedlots, poultry, and swine buildings, are causing a major environmental issue because it has become a primary source of odors, gases, dust, and groundwater contamination. The increasingly stringent requirements for pollution control on livestock manures are challenging the scientific community to develop new waste treatment strategies. Thus, there is a pressing need to develop nonpolluting and renewable energy source utilizing the organic waste (e.g., livestock manure). It is well known that anaerobic digestion had successfully been used for the disposal of manures to produce methane in the last two decades. Recently, an alternative strategy has been developed to convert livestock manures (e.g., dairy manures) to biohydrogen as a high value-added clean energy source instead of methane. However, little information is available on hydrogen production from dairy manure via the mixed anaerobic microbe. As far as we know, the hydrogen production is habitually accompanied with production of volatile fatty acids (VFAs), such as acetate, butyrate, and propionate, which are also an optimal feedstock for production of methane by anaerobic digestion. Provided that the biohydrogen production from dairy manure is further combined with the anaerobic digestion of the effluent from the producing hydrogen reactor that would be a one-stone two-bird paradigm, it not only produces a clean and readily usable biologic energy but also cleans up simultaneously the environment in a sustainable fashion.     

pH对钢铁废水再生过程中CMF系统的影响

通过中试实验研究了钢铁废水再生过程中pH变化对微滤系统性能的影响。结果表明,进水pH的升高增加了微滤膜对UV254、Ca2+和总铁的去除,同时引起了有机物以及无机沉淀物在膜面的吸附。铁锰无机沉淀物在膜面的吸附和对膜孔的堵塞是引起膜污染的主要因素。降低pH有助于控制无机沉淀在膜面和膜孔内的形成,抑制膜污染的形成。     

混合添加剂对PVDF平板疏水膜结构及性能的影响

以不同添加剂采用浸没沉淀相转换法制备基于无纺布支撑的聚偏氟乙烯(PVDF)平板疏水膜,考察了不同添加剂的加入对膜性能与结构的影响;并利用扫描电子显微镜(SEM)、原子力学显微镜(AFM)、红外光谱(FTIR)、接触角测量及膜蒸馏实验等对疏水膜的结构及性能进行表征。结果表明,引入混合型添加剂制备的膜具有较高通量和盐截留率,其疏水性最强,而添加剂对聚合物的晶型影响较小。以35 g/L的NaCl盐溶液为进料液对制备的平板膜进行直接接触式膜蒸馏实验,在热侧进水温度为50℃、冷侧温度为20℃的条件下,所制备的疏水膜通量最高可达12.45 kg/(m2.h),截留率为99.99%。     

Ozone-enhanced catalytic oxidation of monochlorobenzene over iron oxide catalysts

In this study, we examined the experimental catalytic oxidation of gaseous monochlorobenzene (MCBz) with O₃ over Fe₂O₃ in a packed bed reactor to investigate the feasibility of economical low temperature decomposition at a high space velocity (SV). We investigated the effects of several reaction parameters (temperature, O₃ concentration, and SV) on the MCBz oxidation. At 150 °C, the conversion of MCBz over Fe₂O₃ in the absence of O₃ was only 3%; it increased to 91% over Fe₂O₃ in the presence of 1200 ppm of O₃ at a high SV of 83 s⁻¹. A long-term operation study revealed that the conversion of MCBz was stable for more than 96 h. In the steady state, the carbon and chlorine balances were 88% and 86%, respectively. Applying a Langmuir-Hinshelwood kinetic model, we estimated an activation energy of 16.7 kJ mol⁻¹ for MCBz oxidation over Fe₂O₃ in the presence of O₃.