Application of a trapezoidal fuzzy AHP method for work safety evaluation and early warning rating of hot and humid environments

Hot and humid environments are prevalent in many industries. People working in hot and humid environments are at great risk of specific heat-related disorders, the productivity decrease and safety problems. In order to guarantee workers’ health and safety, safety evaluation and early warning rating of the hot and humid environments are studied in this paper. The fuzzy analytic hierarchy process (AHP) method is proposed to evaluate the work safety in hot and humid environments. Trapezoidal fuzzy numbers are adopted to handle inherent uncertainty and imprecision of the data involved in decision process. Within the proposed methodology, a decision group is firstly established. A safety evaluation framework containing three factors (work, environment, and workers) and ten sub-factors are established. The fuzzy weights of the factors and sub-factors are calculated based on the pair-wise comparisons. Then the fuzzy evaluating vectors of the sub-factors and factors can be calculated according to the initial evaluation data. Therefore, the comprehensive safety index, safety grade and early warning grade can be determined. An example is given to demonstrate the proposed method. The results demonstrate the engineering practicability and effectiveness of this method in extreme environment evaluation.     

青萍生长抑制试验对稀脉浮萍的适用性研究

为了验证我国本土常见的稀脉浮萍(Lemna aequinoctialis)是否适用于以青萍(Lemna minor)作为标准试验生物的生长抑制试验,对两种浮萍的毒性效应终点和毒性响应差异进行比较。通过对两种浮萍的总叶面积、干重、鲜重同叶状体数之间的相关性进行分析,根据《OECD化学品测试准则No.221浮萍生长抑制试验》,遵从良好实验室规范(GLP),将两种浮萍暴露于参比物质3,5-二氯苯酚,进行7 d更新式毒性试验,暴露浓度为(1.0~10)mg·L-1。结果表明,青萍的培养条件、试验方法以及毒性效应终点均适用于稀脉浮萍,两种浮萍的毒性试验呈现出相似的时间-效应关系和剂量-效应关系,两者的毒性效应浓度具有可比性,且数值上接近。以上实验结果可以得出,稀脉浮萍适用于生长抑制试验;鉴于稀脉浮萍在我国分布广泛、容易获取,稀脉浮萍可作为毒性测试的国家标准试验生物。     

几种生物学指标与生物强化系统降解效率的关系

针对炼油废水生物强化处理系统中有时存在的不稳定造成排水超标的问题,研究了SBR反应器中采用生物强化技术,其细菌数量、脱氢酶、邻苯二酚1,2-双加氧酶(C12O)和邻苯二酚2,3-双加氧酶(C23O)等关键生物学指标与污染物去除效率的综合对应关系,并运用ERIC-PCR技术研究了运行前后处理系统内微生物群落的变化.结果表明,投加菌剂的生物强化处理系统提高了细菌数量和酶活,使处理效率明显提高.生物强化系统中细菌数量及C23O酶活与污染物去除效率呈正相关关系,且微生物群落结构十分稳定.C12O为一种诱导酶,其酶     

Spill-over characteristics of peroxy-fuels: Two-phase CFD investigations

Two-phase CFD (Computational Fluid Dynamics) model for characterising the spill-over/dispersion of peroxy-fuels is presented. The model is independent of type and burning rate of the spilled/dispersed fuel and considers only overflow Reynolds number (Re) to characterise the spill/dispersion behaviour. Additional simulations are performed for LNG (Liquified Natural Gas) dispersion and it is found that the model can be used for different fuels within a defined range of Re. Different scenarios with Re = 100 to 3 × 10⁵ are investigated covering a wide range of mass flow rates, opening sizes and viscosities. Depending on Lower Flammability Limits (LFL) of the fuels spill/dispersion (vapour cloud) diameters (D_CFD) and heights (h_CFD) are predicted. A generalised correlation between D_CFD and Re is established to predict the dispersion occurring at varying scales. The model is validated by: (1) conducting an extensive grid independent study; (2) comparing the results with the existing analytical methods and (3) comparing against the standard field test data on LNG dispersions.     

MODELING WATER BALANCE WITH THE ERHYM MODEL ON SOUTH TEXAS RANGELANDS1

ABSTRACT: Understanding the hydrologic processes of rangeland plant communities is essential to determine if water augmentation through shrub management is feasible. Vegetation manipulation studies are costly, difficult to accurately replicate, and often require more than 10 years to determine treatment effect on the water budget. If properly applied, hydrologic simulation models are an attractive alternative for assessing vegetation manipulation practices. The ERHYM-II model was evaluated to determine if it was capable of simulating the water balance for honey mesquite shrub clusters, grass interspaces, and bare soil in south Texas. The simulated water budget was within 2 percent of the measured evapotranspiration for the shrub clusters and grass interspaces. The model underestimated the number of runoff events and overestimated runoff volume for the grass interspace and shrub clusters. Simulated runoff was overestimated by approximately twofold for the grass interspace and threefold for the shrub clusters. Although simulated runoff was substantially overestimated, observed and simulated runoff only accounted for 3 to 6 percent of annual rainfall for the grass and shrub dominated areas, respectively. Simulated evapotranspiration was underestimated by 18 percent and soil water content was overestimated by 82 percent for the bare soil. The model underestimated evapotranspiration for the bare soil as a result of restricting evaporative losses to the first soil layer. Based on our analysis, the ERHYM-II model has the potential for simulating the annual water balance for semiarid rangeland plant communities where runoff and deep drainage are limited components of the water balance.     

IMPROVED RAINFALL/RUNOFF ESTIMATES USING REMOTELY SENSED SOIL MOISTURE1

ABSTRACT: Remotely sensed soil moisture data measured during the Southern Great Plains 1997 (SGP97) experiment in Oklahoma were used to characterize antecedent soil moisture conditions for the Soil Conservation Service (SCS) curve number method. The precipitation‐adjusted curve number and the soil moisture were strongly related (r²= 0.70). Remotely sensed soil moisture fields were used to adjust the curve numbers and the runoff estimates for five watersheds, in the Little Washita watershed; the results ranged from 2.8 km² to 601.6 km². The soil moisture data were applied at two spatial scales, a finer one (800 m) measuring spatial resolution and a coarser one (28 km). The root mean square error (RMSE) and the mean absolute error (MAE) of the runoff estimated by the standard SCS method was reduced by nearly 50 percent when the 800 m soil moisture data were used to adjust the curve number. The coarser scale soil moisture data also significantly reduced the error in the runoff predictions with 41 percent and 28 percent reductions in MAE and RMSE, respectively. The results suggest that remote sensing of soil moisture, when combined with the SCS method, can improve rainfall runoff predictions at a range of spatial scales.     

罗布泊野骆驼自然保护区野双峰驼的分布与生态环境的关系

罗布泊野骆驼自然保护区位于我国西部极旱荒漠带 ,以世界级濒危物种———野双峰驼为主要保护对象 ,也保护当地特有的地貌、盐泉、丝绸之路遗迹及其他珍稀动植物物种 ,面积 7 86× 10 4km2 ,实际控制面积 15× 10 4km2 。该保护区分布有野双峰驼约4 0 0～ 4 80头 ,分布于戈壁、低山残蚀丘陵、谷地和沙漠地带 ,在不同生态环境中野骆驼的种群数量及生态习性各异。     

污泥-烟煤基活性炭的制备及其对苯酚的吸附性能

以石化企业在污水处理过程中产生的干化剩余污泥为原料,大同烟煤作辅助添加料,采用化学活化法制备污泥-烟煤基活性炭,探讨了活化剂（ZnCl2）用量、活化温度、活化时间等条件对所制备的活性炭性能的影响。以活性炭的碘吸附值为衡量指标,当污泥：烟煤（质量比）=1：1时获得制备污泥-烟煤活性炭的最佳工艺条件为：浸渍液为ZnCl2：原料（质量比）=2：1,活化温度550℃,活化时间30 min,在该条件下制备的活性炭的碘吸附值为990 mg·g-1,比表面积为836 m2·g-1,产率为46.6%。同时,以苯酚为目标污染物,考察了所制备的污泥-烟煤基活性炭对苯酚的去除效果,结果表明：污泥-烟煤基活性炭投加量为2.0 g·L-1时,4 h后达到吸附平衡,离子强度对吸附容量没有显著的影响,溶液pH在4~10范围内对苯酚有较好吸附,pH=6时苯酚吸附容量为138.9 mg·g-1。与同类吸附剂相比,制备的污泥-烟煤基活性炭可高效吸附水溶液中的苯酚。     

土壤养分的空间变异性及确定样本容量的研究

从澄城、杨陵两地田块均匀多点采取的土样测定结果表明,土壤有机质、硝态氮、铵态氮和水分具有很大的变异性,这种变异性不仅表现在水平方向,也表现在垂直方向,但不同养分在垂直方向上的变异规律不尽相同。因此,在一定精度要求和误差范围内,相同养分在不同土层中的样品容量也不完全相同。只有根据误差理论确定出每层所需的样品容量,才能保证不同土层间的测定结果具有相互可比性。这一研究结果,对指导合理取样和决定样品容量,准确评价不同土层的养分含量,以及研究养分的动态变化等具有一定的参考价值。     

Provenance and threat-sensitive predator avoidance patterns in wild-caught Trinidadian guppies

The antipredator behaviour of prey organisms is shaped by a series of threat-sensitive trade-offs between the benefits associated with successful predator avoidance and a suite of other fitness-related behaviours such as foraging, mating and territorial defence. Recent research has shown that the overall intensity of antipredator response and the pattern of threat-sensitive trade-offs are influenced by current conditions, including variability in predation risk over a period of days to weeks. In this study, we tested the hypothesis that long-term predation pressure will likewise have shaped the nature of the threat-sensitive antipredator behaviour of wild-caught Trinidadian guppies (Poecilia reticulata). Female guppies were collected from two populations that have evolved under high- and low-predation pressure, respectively, in the Aripo River, Northern Mountain Range, Trinidad. Under laboratory conditions, we exposed shoals of three guppies to varying concentrations of conspecific damage-released chemical alarm cues. Lower Aripo (high-predation) guppies exhibited the strongest antipredator response when exposed to the highest alarm cue concentration and a graded decline in response intensity with decreasing concentrations of alarm cue. Upper Aripo (low-predation) guppies, however, exhibited a nongraded (hypersensitive) response pattern. Our results suggest that long-term predation pressure shapes not only the overall intensity of antipredator responses of Trinidadian guppies but also their threat-sensitive behavioural response patterns.