腐殖酸对砂质土壤吸附Cr(VI)的影响

利用系列摇瓶振荡实验,研究了在砂质土壤介质中腐殖酸(HA)对Cr(VI)还原作用及增强土壤表面对其吸附的影响.通过改变反应接触时间、pH值、HA投加量等条件,确定了最佳吸附反应条件.结果表明:砂质土壤中存在HA时,可使Cr(VI)还原为毒性较小的Cr(Ⅲ),明显增强土壤对可溶态Cr离子的吸附能力,比同等条件下无HA的土壤吸附量增大1倍以上.一般整个反应过程约8 h即可达到稳定.pH值对Cr的还原和吸附有很大的影响,酸性条件下的吸附量比碱性条件可增大1倍,最佳pH值为2～4;当pH＞5时吸附能力急剧下降,pH=10时吸附去除量降为20%.有HA存在时砂质土壤土对Cr(VI)的吸附反应为一级动力学反应,K298=0.033 5 min-1,砂土对CrO2-4的等温吸附曲线较好地满足Langmuir公式.     

氢氧化镁铝溶胶MAHs对Cr(VI)吸附性能的研究

采用共沉淀法合成氢氧化镁铝溶胶 MAHs.研究MAHs对模拟Cr(VI)废水的吸附行为和效果.分析溶液pH值、温度、吸附时间、MAHs投加量和Cr(VI)初始浓度等对MAHs吸附性能的影响,并采用XRD和IR表征MAHs结构,探索其吸附机理.结果表明,MAHs对Cr(VI)的适皮宜吸附条件为pH=6、30℃、吸附20 min,其吸附等温线符合Langmuir吸附等温方程.适宜条件下.氢氧化镁铝溶胶MAHs对Cr(VI)的饱和吸附量达90 mg/g,去除率达95%以上,对Cr(VI)具有很强的吸附能力.处理后废水达到因家规定工业废水排放标准(0.5mg/L).氢氧化镁铝溶胶MAHs对Cr(VI)的吸附是由于铬酸根阴离子插入了MAHs样品层间,吸附剂可通过pH=2的Fecl2溶液再生.     

褐煤腐殖酸吸附脱除废水中活性艳红的研究

采用褐煤腐殖酸吸附脱除废水中染料活性艳红X - 3B,研究了吸附动力学、吸附等温线、腐殖酸投加量和溶液pH值对废水脱色效果的影响.结果表明:褐煤腐殖酸对废水中染料活性艳红X-3B的吸附符合二级速率方程;染料的吸附等温线数据都可用Henry方程、Freundlich方程和Langmuir方程描述;废水中染料脱色去除率随腐殖酸投加量的增大而增大,但去除率的变化随投加量增加而降低;废水中染料脱色去除率随着pH值的减小而增大,直至pH =0.5时,去除率达到最大,为100%.说明在一定的条件下,褐煤腐殖酸对废水中染料活性艳红X -3B有一定的去除效果.     

不同条件下活性啤酒酵母对Cr(Ⅵ)吸附的研究

研究吸附时间、pH值、温度、Cr(Ⅵ)初始浓度等因素对活性啤酒酵母吸附Cr(Ⅵ)的影响及最佳条件.采用制备的啤酒酵母菌体吸附剂在摇床(145 r/min)中对Cr(Ⅵ)进行吸附试验,当吸附时间分别为5 min、10 min、20 min、30 min、60 min、120 min、180 min、240 min和300 min时,Cr(Ⅵ)去除率随吸附时间的增加而增加并趋于稳定;当吸附4 h时,去除率达到最大值94.33%,而当吸附1 h时,去除率可达到最大去除率的94.67%.当溶液pH值分别为0.5、1、2、3、4、5、6、7、8、9和10时,33 ℃下去除率随着溶液pH值的增加先增大后减小;当pH＝2时吸附效果最好,去除率达到99.31%.吸附温度为25 ℃、33 ℃和40 ℃时,去除率随着温度的升高而增加,但温度过高会使啤酒酵母失活且能耗较大,而常温吸附即可达到较高的去除率(78.19%).当Cr(Ⅵ)初始质量浓度分别为15 mg/L、20 mg/L、25 mg/L、30 mg/L、35 mg/L和40 mg/L时,去除率总体上随着Cr(Ⅵ)质量浓度的增加而减小.本研究可为含Cr(Ⅵ)废水的生物吸附处理提供指导.     

活性炭吸附处理含砷废水的研究

通过活性炭的静态吸附实验,研究溶液中砷的去除率与溶液初始pH值、溶液浓度、反应温度和时间、以及溶液中其他共存离子的关系,以确定活性炭吸附去除砷的最佳工艺条件.研究表明,质量浓度为10 mg/L的含砷溶液,在25 ℃,溶液初始pH值为4.5,反应300 min时,砷的去除率达最大值98.6%;若溶液中同时含有Cr(Ⅵ)离子,可提高活性炭对砷的吸附去除率至99%以上.由此可见,活性炭吸附法处理含砷废水的去除率较高,处理后砷含量能够达到国家规定的排放标准.     

CTMAB改性沸石及其对对硝基苯酚吸附效果的研究

为提高沸石对水体中有机污染物的吸附效果,采用酸热活化-十六烷基三甲基溴化铵(CTMAB)改性沸石,研究了改性沸石吸附对硝基苯酚的能力,探讨了改性条件对沸石吸附能力的影响和改性沸石吸附对硝基苯酚的适宜条件.结果表明,改性溶液中CTMAB的量低于沸石阳离子交换量时,沸石负载表面活性剂的量越大,所得到的有机沸石对对硝基苯酚的吸附能力越强; 改性溶液pH值增大,所获得的有机沸石吸附对硝基苯酚的能力也增强.CTMAB溶液的质量分数为1.1%,改性时间为2 h所制备的有机沸石对对硝基苯酚有较高的去除率.在利用已制备的有机沸石处理污水中对硝基苯酚的实际应用中,有机沸石投加量为25 g/L,对硝基苯酚溶液在pH值为6,振荡50 min的条件下,有机沸石对对硝基苯酚的去除率可达98.3%.     

麻疯树籽壳生物质炭的制备及对六价铬离子的吸附研究

以麻疯树籽壳为原料经磷酸活化后炭化处理制备了生物质炭吸附剂。以六价铬离子为目标对象,考察了磷酸浓度、活化时间、炭化温度、炭化时间等制备条件对生物质炭吸附六价铬离子的能力,并探讨了生物质炭的投加量、溶液pH值等工艺条件对六价铬离子吸附能力的影响。结果表明:在磷酸浓度为2 mol/L,活化18 h,600℃下炭化1.5 h时所制得的生物质炭在投加量为5 g/L、溶液pH值为3时对铬离子的吸附效果最佳,铬离子去除率为74.5%。     

腐殖酸吸附Cr(Ⅵ)的对比实验研究

研究了未处理的腐殖酸(HA)和不溶性腐殖酸(IHA)对Cr(Ⅵ)的吸附作用.进行了反应时间、pH值、IHA投加量、温度等对去除效率的影响研究,确定了两种吸附剂最佳反应条件,并通过对比实验,分析了两种吸附剂吸附Cr(Ⅵ)的特点.实验表明,HA达到最大吸附量时所需要的反应时间(180 min左右)远远高于IHiA的反应时间...     

花生壳吸附Cr(Ⅵ)动力学方程研究

通过试验对粒径介于0.25～0.50mm的花生壳颗粒吸附Cr(Ⅵ)的动力学行为进行探讨,从吸附时间、pH值、吸附剂投加量、温度、Cr(Ⅵ)的初始质量浓度方面对吸附性能的影响进行研究.结果表明,最佳吸附条件为:Cr(Ⅵ)初始质量浓度100 mg/L,pH=2.0,振荡速度140 r/min,温度30℃.此时Cr(Ⅵ)的吸附率可达到90%以上.用Lagergren一级吸附速率方程、二级吸附速率方程及平均绝对偏离率对以上因素对吸附件能的影响数据进行处理,发现二级吸附动力学模型可以更好地描述各种影响因素条件下的吸附过程.二级吸附速率常数随着溶液pH值和Cr(Ⅵ)初始质量浓度的减小而增大.在低浓度和低pH值的条件下,Cr(Ⅵ)主要以HCrO4-形式存在,并且HCrO4-是花生壳主要吸附的Cr(Ⅵ).二级吸附速率常数随着溶液温度的升高而快速的增加.温度对反应速率的影响可以通过Arrhenius方程来描述,所得曲线近似为直线方程,决定系数R2=0.986 2,反应的活化能Ea为8.67kJ/mol,该反应活化能在物理吸附反应活化能范围(0～40 kJ/mol)内.     

活化煤矸石对含铬废水的吸附处理研究

研究了活化煤矸石吸附处理模拟含铬废水.结果表明:铬初始质量浓度为100 mg/L时,Cr(Ⅵ)与煤矸石比值为5 mg/3 g,废水pH值控制在10,吸附接触时间为4 h,废水处理效果最佳,铬去除率可达90%以上;吸附符合Freundlich等温模式,吸附等温方程式为log q=0.778 0 0.971 6 log c,以物理吸附为主.     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.     

HAZOP结合What-if方法在某延迟焦化装置除焦中的应用

为克服传统危险与可操作性（HAZOP）定性分析方法在复杂操作、间歇作业等过程中使用的局限性,提出在传统HAZOP定性分析方法的基础上结合What-if（故障假设）方法,对人的不安全行为和操作规程不完备所导致的风险后果分析作出补充。详细说明其技术原理、工作流程等使用细节,系统阐述该方法与传统HAZOP定性分析方法的区别,并在某延迟焦化装置的除焦操作的风险分析中应用。经分析,识别出在“给水-泡焦”节点,有“操作规程错误”场景2项,“操作规程不具体”场景1项,不存在“操作人员未按操作规程执行”场景。研究结果表明:本文方法有效且具有较好效果,可以广泛应用于操作规程/作业指导书审查、作业过程隐患排查等方面,帮助企业开展操作层面的风险识别与管理,提升企业的生产安全水平。     

Nighttime pedestrian fatalities: A comprehensive examination of infrastructure,user, vehicle,and situational factors

Introduction: Pedestrian fatalities in the United States increased 45.5% between 2009 and 2017. More than 85% of those additional pedestrian fatalities occurred at night. Method: We examine Fatality Analysis Reporting System (FARS) data for fatal pedestrian crashes that occurred in the dark between 2002 and 2017. Within-variable and before/after examinations of crashes in terms of infrastructure, user, vehicle, and situational characteristics are performed with one-way analysis of variance (ANOVA) and two-sample t-tests. We model changes in crash characteristic proportions between 2002–2009 and 2010–2017 using linear regressions and test for autocorrelation with Breusch-Godfrey tests. Results: The increase in fatal nighttime pedestrian crashes is most strongly correlated with infrastructure factors: non-intersection unmarked locations (saw 80.8% of additional fatalities); 40–45 mph roads (54.6%); five-lane roads (40.7%); urban (99.7%); and arterials (81.1%). In addition, SUVs were involved in 39.7% of additional fatalities, overrepresenting their share of the fleet. Increased pedestrian alcohol and drug involvement warrant further investigation. The age of pedestrians killed increased more (18.1%) than the national average (3.2%). Conclusions: By identifying factors related to the increase in nighttime pedestrian fatalities, this work constitutes a vital first step in making our streets safer for pedestrians. Practical Applications: More research is needed to understand the efficacy of different solutions, but this paper provides guidance for such future research. Engineering solutions such as road diets or traffic calming may be used to improve identified infrastructure issues by reducing vehicle speeds and road widths. Rethinking vehicle design, especially high front profiles, may improve vehicle issues. However, the problems giving rise to these pedestrian fatalities are likely a result of not only engineering issues but also interrelated social and political factors. Solutions may be correspondingly comprehensive, employing non-linear, systems-based approaches such as Safe Systems.     

潞安矿区煤层渗透率的各向异性特征实验研究

为了研究原位煤体渗透性的各向异性特征,以山西潞安常村矿3号煤层圆柱试样为对象,利用TCQT-Ⅲ型低渗煤层气相驱替增产试验装置,对煤样进行加载,并以氮气注入压力2.0 MPa的条件下,分析垂直层理和平行层理2个方向的煤体变形和渗透率变化特征。实验结果表明:煤样在加载过程中,平行和垂直层理煤样渗透率均随着有效应力的增大而减小,平行层理方向的渗透率始终大于垂直层理方向,应力加载初期渗透率急剧下降,最后逐渐趋于平缓;径向应变的增加量与渗透率呈正相关性,且平行层理相关性大于垂直层理;沿平行层理方向的裂隙度大于沿垂直层理方向,沿垂直层理方向的应变量大于沿平行层理方向;应变增加量均随有效应力的增加而逐渐减小。研究结果可为煤层井网布置及优化提供参考。     

森林地表火蔓延模拟方法及其计算机实现

进行了森林火蔓延的研究,对传统的经验公式和模型进行改进,明显发现改进的模型有更好的结果,用计算机巧妙准确地实现了模拟模型,在风力不是特别大,地形变化不是特别剧烈时,该模型有较高精度;并结合火蔓延的主要因素（气象因子、气候、地形等）,进行系统分析,写出算地,编制实现地表火蔓延的预测预报计算机系统软件。这对于有效的组织扑救、减少火灾损失、计算森林火灾的损失评估有重要意义。     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

AHP与GA-SVM耦合模型在滑坡预警中的应用*

为了减少滑坡造成的损失,提高滑坡预测的准确性,通过搭建灾害模拟平台获得滑坡的实验数据,在获得多组模拟实验数据后,分析各变量的特性。首先,通过层次分析(Analytic Hierarchy Process,AHP)算法,对滑坡进行危险度划分;然后,通过支持向量机(Support Vector Machine,SVM)建立模型,遗传算法(Genetic Algorithm,GA)再优化SVM参数,提出1种层次分析法与GA-SVM相耦合的模型。研究结果表明:AHP方法划分后的数据,通过GA与SVM结合建立的模型精度较好,实验预测结果与实际结果较为吻合,与单一SVM相比,精度更高,结果更好,更加适用于多变量的复杂非线性滑坡预警。     

Debunking the false dichotomy of leadership idealism and pragmatism: Critical evaluation and support of newer genre leadership theories

Leadership theories have shifted over the last few decades from a focus on managerial functions and economic leader–follower exchanges toward greater focus on the interpersonal dynamics occurring within the leadership process. Theories such as transformational, ethical, authentic, and other “newer genre” theories were created to address neglected topics such as leader vision and inspirational messages, transparency, emotional effects, morality, individualized attention, and intellectual stimulation. Critiques of these theories, however, have been raised. In this paper, we address five of those critiques and argue for the validity and practical effectiveness of the new genre theories. Further, we describe how newer genre leadership research should be viewed as a performative epistemology, entailing a process of co‐creation involving scholars and practitioners. Finally, from this view, we provide general ideas for leader development. Copyright © 2014 John Wiley & Sons, Ltd.     

Occupational Safety and Health in Finland

In Finland, occupational safety is the responsibility of the employer, while the occupational safety and health laws are enforced by the Labour Inspection Service, an organization of the state. The Labour Inspection is divided in 11 administrative districts, and it employs 360 professionals. They are mandated to carry out site visits without prearranged appointments to inspect safe work situations, working hours, construction safety, or any aspect of accident risks. The inspectors are also mandated to verify the existence of sufficient occupational health services as prescribed by the Occupational Health Services Act for all employees. The occupational health services are typically provided by enterprise-owned medical departments, by mutually owned health care centers, by private practitioners, or by municipal health care centers. The latter are required by law to provide all services as prescribed by the legislation to anyone who comes to the facility. This situation is prevalent in the countryside, where there are very few private caregiving centers. Declaring occupational accidents and disease cases is mandatory, and the Inspection districts examine all accidents to establish causes and consequences, and to initiate prosecution in case of criminal negligence. Labour Inspection Districts are also notified of the new occupational disease cases as they are declared to insurance companies. Insurance for occupational disease, accidents, and death is an obligation of the employer, although they can choose the insurance company. The medical confidentiality between the workers and their occupational health care providers is very strict. Official statistics are maintained by the state Statistics Finland organization, and they may be used, for example, for research purposes by scientific institutes like the Finnish Institute of Occupational Health. Construction industry accounts for 25% of all fatal accidents (120 cases per 1 million working hours), followed by mechanical, wood, metal, machinery, and pulp and paper industry (10% each of fatal accidents) with rates ranging from 100–160 cases per 1 million working hours. There are some 5,000 occupational disease cases per year (rate 22/10,000 employed). The major disease categories include repetitive strain injuries (1,300 cases), respiratory allergies (600 cases), occupational skin diseases (1,000 cases), and 900 cases of noise-caused hearing loss. In 1998, 589 cases of asbestos-related diseases were reported.     

公路隧道火灾逃生疏散研究

以苍岭隧道为背景,首先采用经验计算理论和计算软件building EXODUS相结合的方式,从被困人员的安全疏散时间、高温烟气的影响、隧道横通道的利用率以及人员的疏散行为特性进行了研究。结果表明:中小规模火灾情况下的安全疏散时间控制在8 min之内,高温烟气影响不大,但横通道的利用率不平均,且人员疏散路线相对集中。然后对存在的逃生疏散问题提出针对性建议以及其他相关建议,旨在为更大程度降低事故的严重性和经济财产损失。