基于体积应变含瓦斯煤增透率模型及采动响应研究

为获得含瓦斯煤开采过程中渗透率的采动响应规律,从孔隙率的基本定义出发,通过引入增透率来反映单位体积改变下煤体渗透率的变化,建立了基于体积应变的含瓦斯煤增透率模型。基于增透率模型,结合工程实例采用Comsol Multiphysics模拟了含瓦斯煤开采过程中增透率的变化规律,并开展了增透率采动响应的试验研究。研究结果表明:增透率模型可对采动裂隙网络形成的煤层透气性进行定量评价研究,采动是影响含瓦斯煤增透率的关键因素,受采动影响,煤体体积应变、增透率的变化规律均基本一致,煤体膨胀变形、增透率随采煤工作面的推进逐渐增大,增透率的变化滞后于体积应变的变化,且越靠近工作面煤层增透效果和瓦斯抽采效果越好;沿煤层倾向,回风巷侧最大瓦斯抽采量大于运输巷侧,煤体增透率亦大于运输巷侧。依据增透率的采动响应规律调整瓦斯抽采孔与工作面的角度,可增加抽采量,降低工作面瓦斯浓度。     

Assessment of mammal reproduction for hunting sustainability through community‐based sampling of species in the wild

Wildlife subsistence hunting is a major source of protein for tropical rural populations and a prominent conservation issue. The intrinsic rate of natural increase. (r_max) of populations is a key reproductive parameter in the most used assessments of hunting sustainability. However, researchers face severe difficulties in obtaining reproductive data in the wild, so these assessments often rely on classic reproductive rates calculated mostly from studies of captive animals conducted 30 years ago. The result is a flaw in almost 50% of studies, which hampers management decision making. We conducted a 15‐year study in the Amazon in which we used reproductive data from the genitalia of 950 hunted female mammals. Genitalia were collected by local hunters. We examined tissue from these samples to estimate birthrates for wild populations of the 10 most hunted mammals. We compared our estimates with classic measures and considered the utility of the use of r_max in sustainability assessments. For woolly monkey (Lagothrix poeppigii) and tapir (Tapirus terrestris), wild birthrates were similar to those from captive populations, whereas birthrates for other ungulates and lowland‐paca (Cuniculus paca) were significantly lower than previous estimates. Conversely, for capuchin monkeys (Sapajus macrocephalus), agoutis (Dasyprocta sp.), and coatis (Nasua nasua), our calculated reproductive rates greatly exceeded often‐used values. Researchers could keep applying classic measures compatible with our estimates, but for other species previous estimates of r_max may not be appropriate. We suggest that data from local studies be used to set hunting quotas. Our maximum rates of population growth in the wild correlated with body weight, which suggests that our method is consistent and reliable. Integration of this method into community‐based wildlife management and the training of local hunters to record pregnancies in hunted animals could efficiently generate useful information of life histories of wild species and thus improve management of natural resources.     

Antibacterial potency of housefly larvae extract from sewage sludge through bioconversion

Use of the fly to convert sewage sludge into nutrient-rich soil conditioner and amendment is an attractive approach for sludge bioconversion. During this process, fecal coliforms, an indicating pathogen, in sludge were reduced to 5.3 × 102 most probable number /g dry solid from initial 3.32 × 106 MPN/g dry solid. It was also found that the extract of larvae grown in sludge during bioconversion have an observable inhibitory effect against bacteria compared to larvae grown in wheat bran as measured by minimum bacterial concentration tests. In vitro antimicrobial assay tests over time also showed that the extract had strong inhibitory efficiencies of ca. 99% against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Serratia marcescens, while the efficiency was 69% and 57% against Bacillus subtilis and Klebsiella pneumoniae, respectively. The observed pathogenic bacterial cell membrane damage was found to be responsible for the phenomenon mentioned above, with nuclear acids leaching out quickly and alkaline phosphatase increasing in the outer membrane, followed by an increase of β-galactosidase in the inner membrane. Clearly, housefly larvae extract from sewage sludge through bioconversion possesses antibacterial potency against pathogenic bacteria.     

基于渗透特性的MSW颗粒组成和结构分析

在南方某填埋场埋深5~30m范围内取6组重约5kg的试样,对其进行筛分与分拣,研究垃圾颗粒组成随埋深的变化规律,同时对不同荷载作用下的垃圾试样进行染色切片,对比分析上覆压力对垃圾内部结构的影响.结果表明：对于不同埋深的城市固体废弃物,细颗粒（0D,即粒径<2cm）所占比例最大,几乎均超过50%,粗粒中2D颗粒所占比例最高,而塑料在2D颗粒中占比最大;随着荷载的增大,细粒含量增加,大孔隙和优先流通道减小.上覆压力主要通过减少垃圾内部孔隙通道,进而减小渗透系数;2D颗粒在荷载的作用下能定向排列,使渗流路径发生曲折,进而导致渗流各向异性.2D颗粒的定向排列是垃圾渗流各向异性产生的关键因素,其中塑料又是其最重要的因素.     

A New Approach to Measuring Work-Related Well-Being

The main aim of this study was to develop a short questionnaire to assess work-related well-being from the organizational behaviour perspective. The short well-being questionnaire enables measuring longitudinal work-related well-being. Work-related well-being was assessed with a 147-item questionnaire covering both organizational and intrinsic factors of work-related well-being. The questionnaire consisted of 27 categories. The respondents were 114 women (65%) and 62 men (35%), mean age 39.2 years, in various occupations. From the extensive questionnaire a shorter questionnaire with 33 items was developed by principal component analysis. The Kaiser-Meyer-Olkin measure to test the sampling adequacy of 27 factor solutions varied from .62 to .91 and Cronbach’s a was .74–.94. Most K values of the shorter questionnaire were .50–.94 (p < .001). The reliability of the short version was comparable to that of the original questionnaire. The short one could also be suitable for Internet and mobile questionnaire applications.     

河道淤泥的轻质化处理及其工程性质

基于河道淤泥综合有效利用的目的,利用其高含水的特征,采用气泡混合轻质化技术对河道淤泥进行轻质化处理。通过室内试验的方法,考察和评价了以河道淤泥为原料土的气泡混合轻质土的基本工程性质,包括它的强度特性、变形特性、渗透性及耐久性能等。研究结果显示,经气泡混合轻质化处理的河道淤泥,具备一般填土的强度与刚度特性,其品质与施工性与固化材料的掺入量有密切的关系,固化后的轻质土具有良好的防渗透能力,但在循环干湿作用下易发生品质劣化现象。研究结果可以作为河道淤泥工程应用的基本依据及质量控制指标,同时也为进一步开发研究建立一定的基础。     

Control of petroleum-hydrocarbon contaminated groundwater by intrinsic and enhanced bioremediation

In the first phase of this study, the e ectiveness of intrinsic bioremediation on the containment of petroleum hydrocarbons was evaluated at a gasoline spill site. Evidences of the occurrence of intrinsic bioremediation within the BTEX (benzene, toluene, ethylbenzene, and xylenes) plume included (1) decreased BTEX concentrations; (2) depletion of dissolved oxygen (DO), nitrate, and sulfate; (3) production of dissolved ferrous iron, methane, and CO2; (4) deceased pH and redox potential; and (5) increased methanogens, total heterotrophs, and total anaerobes, especially within the highly contaminated areas. In the second phase of this study, enhanced aerobic bioremediation process was applied at site to enhance the BTEX decay rates. Air was injected into the subsurface near the mid-plume area to biostimulate the naturally occurring microorganisms for BTEX biodegradation. Field results showed that enhanced bioremediation process caused the change of BTEX removal mechanisms from anaerobic biodegradation inside the plume to aerobic biodegradation. This variation could be confirmed by the following field observations inside the plume due to the enhanced aerobic bioremediation process: (1) increased in DO, CO2, redox potential, nitrate, and sulfate, (2) decreased in dissolved ferrous iron, sulfide, and methane, (3) increased total heterotrophs and decreased total anaerobes. Field results also showed that the percentage of total BTEX removal increased from 92% to 99%, and the calculated total BTEX first-order natural attenuation rates increased from 0.0092% to 0.0188% per day, respectively, after the application of enhanced bioremediation system from the spill area to the downgradient area (located approximately 300 m from the source area).     

湿式除尘器氢气爆炸事故控制研究*

为降低铝合金湿式除尘系统发生氢气爆炸事故的风险,提出1种氢气抑制的方法用来降低铝合金湿式除尘系统发生氢气爆炸事故的可能性。选取柠檬酸钠作为抑制剂开展抑氢实验研究,得到不同浓度的柠檬酸钠溶液随时间变化的抑氢曲线。当柠檬酸钠溶液浓度为0.4~4 g/L时,能有效抑制铝合金粉尘与水的反应。通过扫描电子显微镜(scanning electron microscope,SEM)和能量色散谱（energy dispersive spectroscopy,EDS)分析对铝合金粉与柠檬酸钠溶液反应后的产物进行表征。最后,对本文提出的抑氢方法的经济性进行分析,明确该方法在节约安全投入方面具有非常明显的优势。抑氢本质化安全设计方法为控制铝合金湿式除尘系统氢气爆炸事故提供了1种新的思路,同时也可被控制核反应堆氢气爆炸事故所借鉴。     

基于文献计量的国内危险化学品信息化监管主题与热点分析*

为提升危化品安全信息化监管建设能力与本质安全水平,通过文献计量法和CiteSpace软件,采用关键词共现和聚类归纳对危化品领域及技术研究趋势进行分析。结果表明:危化品安全信息化监管研究自1998年共经历萌芽、发展、摆动3个阶段,但高质量成果较少;在当前新兴信息技术和传统评价分析技术相结合的新型研究模式下,着重突出物联网、大数据、人工智能、区块链等智能技术占比,是未来危化品信息化监管发展重要途径。     

A case study of promoting CH4 discharge and preventing coal & gas outburst accidents by using cross-layer liquid injection technology

To solve the problem of gas extraction in coal bodies with the outburst risk, the cross-layer drilling fluid injection technology for protecting rock pillars is adopted to promote gas extraction. We combined theoretical calculations, laboratory experiments, and field tests to analyze the degree of fissure development in different parts of the coal body. We also determined the liquid injection parameters and negative extraction pressures. The CH₄ extraction effects of three stages before, during, and after liquid injection was compared. The results show that the possibility of coal outbursts in different parts is reduced by 58%∼70% by using liquid injection and pumping technology. The peak value of CH₄ pure flow in the main pipe is increased by 1.5–2.8 times, and the average value is increased by 1.8–2.6 times. The peak value of gas concentration at the orifice of the extraction hole is increased by 1.6–3.5 times, and the average value is increased by 1.6–4 times. Liquid injection to promote extraction greatly improves the gas extraction efficiency in coal bodies, which is of great significance to reducing cost, shortening the construction period, and ensuring safe production, and providing a reference for similar engineering construction.