Comparison of Soil Extraction Isotherms of Soil Samples Saturated With Nonpolar Liquids

In multiphase systems capillary pressures play a significant role on fluid movement and retention. The facility to predict the effect of different thermal remediation strategies requires the knowledge of the effect of temperature on capillary pressure-saturation relationships in the soils. The objective of recent study was (a) to develop a technique for routinely measuring the pressure-saturation curves of soil samples saturated with a nonpolar liquid at different regulated temperatures (b) to build a database using the measured pressure-saturation curves and the physical, chemical properties of the model soils (c) to establish the dependence of nonaqueous phase liquid retention on the soil properties and the temperature. The retention curves (extraction isotherms) with nonaqueous phase liquid were determined using a modified pressure plate extractor. The wetting phase was a non-aromatic hydrocarbon distillation product. Pressure plates were designed and constructed in the laboratory of our department. The temperature was held constant at 20, 40 and 60 ^∘C. Statistical analysis was performed involving selected soil parameters and the measured nonaqueous phase liquid retention data. The results show that knowing some easily measurable soil parameters (bulk density, particle size distribution, humus and lime content) we can estimate the nonaqueous phase liquid retention of the soils. The measured “extraction isotherms” provide essential information about the temperature-dependency of pressure-saturation curves.     

人工湿地污水处理系统脱氮研究进展

系统地介绍了人工湿地去除污水中氮污染物的机理及国内外研究进展，详细阐述了影响人工湿地污水处理系统脱氮的内、外界因素，对于人工湿地污水处理工艺的推广应用提供科学依据。     

累托石对水中染料碱性桃红的吸附

采用累托石作为水中碱性桃红的吸附剂.考察了振荡时间、pH值、累托石用量、碱性桃红初始浓度等因素对吸附效果的影响.测定了吸附等温线,对吸附动力学规律进行了数学模拟.结果表明,振荡时间、累托石用量、碱性桃红初始浓度等因素对吸附效果有重要影响.对于初始质量浓度为50 mg/L的碱性桃红水溶液,最适宜吸附条件为:振荡时间30 min,累托石用量200 mg/100 mL,pH值为6.累托石对水中碱性桃红的吸附等温线呈"S"型,等温吸附规律可用Freundlich模式较好地描述,吸附动力学规律可用Bangham公式模拟.     

农业非点源污染田间模型及其应用

非点源污染的负荷定量化研究是控制、评价和管理非点源污染的基础.农业非点源污染负荷估算包括农田排水估算和排水中的污染物浓度预测2个环节.依据水量平衡原理,农田排水应用DRAINMOD模型估算;将农田的施肥和灌溉过程"合成"作为田间污染物浓度的脉冲输入,农田排水中的污染物浓度变化则视作对应于此脉冲输入的响应过程,而污染物在田间的复杂迁移转化过程以逆高斯概率密度函数隐含表达.以此为基础,构建了农田尺度农业非点源污染负荷估算模型.以青铜峡灌区典型试验区为例,对稻田排水沟中硝态氮(NO_3~--N)和总磷(TP)的负荷过程进行了模拟,结果表明,模型估算结果和实测污染物负荷过程非常接近,Nash-Suttcliffe模拟效率系数分别为0.963和0.945,表明该模型具有较高的可靠性.     

Fenton氧化破解剩余污泥中的胞外聚合物

利用Fenton试剂的强氧化性破解剩余污泥中的胞外聚合物（EPS）,通过释放出的多聚糖、蛋白质浓度以及SCOD的变化表征EPS的破解程度,旨在找出Fenton氧化破解EPS的适宜反应条件．结果表明,pH = 2.5,反应时间90 min,H₂O₂/Fe²⁺（质量比）= 8∶1,温度65～70℃为适宜反应条件．该条件下经Fenton氧化,污泥上清液中的SCOD、多聚糖和蛋白质浓度分别由45.88、 10.96和11.99 mg·L^-1增加到684.93、 382.17和302.62 mg·L^-1;污泥颗粒平均粒径和中值粒径分别由供试污泥的838.89 μm和859.20 μm减小到137.22 μm和148.69 μm．Fenton氧化可以有效破解污泥中的EPS,提高污泥的无机化程度,有利于污泥的减量化和资源化．     

采用Zn-Se/不锈钢阴极的超声-电解法处理罗丹明B废水

采用超声-电解法考察了Zn-Se/不锈钢阴极处理罗丹明B废水的效果及影响因素。正交实验优化结果表明:在电流密度为2.4A/dm2、废水初始pH为6、超声功率为160W、通气量为10L/h、m(Zn)∶m(Se)为1∶1.5的Zn-Se/不锈钢作阴极、Ti/TiO2和铁网为双阳极的条件下,超声-电解法处理罗丹明B废水120min,废水脱色率为98.97%,COD去除率为88.11%。     

Behavioural reactivation and subjective assessment of the state of vigilance--application to simulated car driving.

The frequency of some behaviour (such as self-centred gestures) increases during a task that leads to the occurrence of low-vigilance episodes. These gestures can be useful in stimulating oneself. A study carried out in 20 adults has enabled us to state that motor activity (recorded with an actimeter) increases with the duration of a monotonous driving task and sleep deprivation. The analysis of the scores recorded using the Karolinska Sleepiness Scale has shown that drivers can assess the deterioration of their state of vigilance according to the actual sleep preceding the driving test. Finally, the joint analysis of the subjective and objective data revealed a co-variation of these two types of indices. We discuss the stimulatory function of the motor activity in a task leading to the occurrence of low-vigilance episodes by investigating, among other things, the use, conscious or not, of this type of activity.     

The Effect of Protective Gloves on Manual Dexterity in the Cold Environments

This article presents a study on the effect of different protective gloves (which are commercially available and commonly used in the cold) on manual dexterity in cold environments. The experiments compared statistically four different types of gloves and two different types of gloving (outer or double) at +19 °C and -10 °C. Performance was determined both objectively and subjectively using two manual dexterity tasks: bolt-nut and pick-up tasks. The response measured was the time of performing each task. Statistical analysis showed that all independent factors such as glove type, participant, object size, and temperature had significant effects on the hand cooling reaction. A significant difference in the performance between the gloves was found in the bolt-nut task. It was also found that outer-inner combination gloving may be an approach to use for precision tasks.     

Effect of Sweating on Insulation of Footwear

The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19–25% (30–37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.     

Determination of Heat Loss from the Feet and Insulation of the Footwear

This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of thermal foot method, the latter should be preferred for testing.