Thermodynamics and kinetics of cadmium adsorption onto oxidized granular activated carbon

Cadmium sorption behavior of granular activated carbon oxidized with nitric acid was systematically studied by sets of the equilibrium and time-based experiments under various conditions.The cadmium adsorption capacity of oxidized granular activated carbon enlarged with an increase in pH,and reduced with an increase in ionic strength.Experimental data were evaluated to find out kinetic characteristics.Adsorption processes were found to follow pseudo-second order rate equation.Adsorption isotherms correlate well with the Langmuir isotherm model and the maximum sorption capacity of cadmium evaluated is 51.02μmol/g.Thermodynamic parameters were calculated based on Van't Hoff equation.Equilibrium constant Kd was evaluated from Freundlich isotherm model constants,Langmnir isotherm model constants,and isotherms,respectively.The average change of standard adsorption heatΔH~0 was -25.29 kJ/mol.NegativeΔH~0 andΔG~0 values indicate the adsorption process for cadmium onto the studied activated carbon is exothermic and spontaneous.The standard entropyΔS~0 was also negative,which suggests a decrease in the freedom of the system.     

We should allow dissection of animals

The focus of the paper is the ethical issues associated with the practice of dissecting animals in lower level college biology classes. Several arguments against dissection are explored. Furthermore, the issue is examined from the point of view of the instructor's academic freedom and the point of view of a student's moral autonomy. It is argued that even though the arguments against dissection fail, it is very important to respect the moral autonomy of students who oppose the practice. Often this can be accomplished in a manner that is consistent with academic freedom and good science education.     

力限振动试验技术应用与研究

首先介绍传统加速度振动试验产生过试验的主要原因;接着介绍机械阻抗特性,给出视在质量、有效质量及剩余质量的定义;然后通过对复杂二自由度方法进行理论推导,给出力限试验条件的制定方法;最后以铝板为例,建立典型力限控制试验方案,提出力限试验方法及试验步骤。从试验结果看,力限控制试验方法是缓解试件过试验的一种有效方法。     

风场类型对高层建筑风致响应的影响研究

风荷载是影响高层建筑安全性的重要因素之一,而不同的风环境会对高层建筑的风致响应存在不同程度的影响,基于此背景,本文通过高层建筑多自由度气动弹性模型风洞试验,获得了结构原始加速度时程曲线,采用随机减量法对其气动阻尼进行识别,分析了风场类型对高层建筑气动阻尼比和风致加速度响应的影响。结果表明:横风向气动阻尼比随折减风速的变化起伏较大,顺风向气动阻尼比随折减风速的增大而增大;折减风速小于特定值时,地貌类型对气动阻尼影响较小;随着风场类型从A类变化为D类,结构横、顺风向的气动阻尼比的变化趋势趋于平缓,气动阻尼比的正峰值减小,正峰值风速增大。高层建筑横风向的加速度响应大于顺风向;风场类型从A类变化为D类的过程中,横、顺风向的加速度响应均减小。风向角对气动阻尼比和加速度响应均存在较明显的影响。     

基于Sen可行能力理论测度中国社会福利指数

本研究基于阿玛蒂亚·森(Sen)可行能力理论,运用2008-2013年中国31个省(市)面板数据,采取模糊数学理论与主成分因子分析法测度中国社会福利指数。通过理论与实证研究发现:第一,东中西部地区社会福利指数差异性较大,其波动呈不规则趋势,且社会福利与经济发展呈脱钩状况。第二,计算MI与GC指数发现,各地区社会福利指数之间存在正的空间相关性,且东中西部地区社会福利指数存在空间集聚与扩散现象。第三,利用动态空间面板模型实证检验发现,社会福利指数存在时滞性,且城镇化率与外贸出口占比越高,越有利于提高社会福利水平,而经济增长与工业化对社会福利影响力相对较低。鉴于此,为有效提高中国社会福利,使经济发展与社会福利二者相匹配,本研究提出以下政策建议:首先,学术界应改变传统的福利经济学思维体系,将更多的研究重点放在功能自由与能力自由两方面。其次,各地区应加强区域间交流合作,减少"以邻为壑"现象,促进区域发展一体化。最后,中央与地方政府应转变经济发展模式与理念,加大民生与环境保护方面投入,进而提高居民生活质量。     

药用蕈菌姬松茸液体培养的菌丝形态学特征

在液体分批培养体系中,研究了药用蕈菌姬松茸Agaricus blazei悬浮菌丝物的形态多样性及其生长特征.A.blazei菌丝物形态由初始的"分枝菌丝物"(Ⅰa与Ⅰb)演变成"絮簇菌丝物"(Ⅱa与Ⅱb),进而成为 "颗粒菌丝物"(Ⅲa与Ⅲb).对于以上空间构象,作者提出了"菌丝自由度"概念.它从菌丝物立体结构上,描述了菌丝物内菌丝处在不同疏松度微环境中的空间特征,可表示为F=V/M=∑Ni=1(ΔV)i/∑Ni=1(ρ*ΔV)i=N/(ρ1+……+ρN),培养试验中,分别比较了2 d、5 d与8 d的摇瓶种液菌龄,以及氮源辅助基质D1 为50 g L-1与100 g L-1时对悬浮菌丝物生长的影响;同时,还比较了ALR/ff反应器结构的特征参数 "回流区高度比值h/H" (内导流筒高度h与液面高度H之比)改变时A.blazei的生长情况.结果表明,絮状(Ⅱa、Ⅱb)菌丝物具有较高的生长能力,良好的生长过程与生长单元具有较高F值有关. 图9 参18     

空气质量自动监测二氧化硫不确定度分析

不确定度是反映某一测量方法,在一定置信概率条件下测量所产生的不确定量。根据测量原理建立数学模型,分析各种不确定度分量的来源,评定标准不确定度,确定合成不确定度和扩展不确定度,通过不确定影响分量的分析,找出影响测量结果的最大不确定度分量,重点控制其分量,保证测量的准确性和精度,同时也可通过重新评估显著性不确定分量,找出方法存在的不足和问题,提出逐步控制不确定分量的步骤和方法,改善测量方法和手段提高测量准确性和精度,不断减少测量的不确定量。     

You are What You Eat: Meat, Novel Protein Foods, and Consumptive Freedom

Animal husbandry has been accused ofmaltreating animals, polluting the environment, and soon. These accusations were thought to be answered whenthe Dutch research program ``Sustainable TechnologicalDevelopment' (STD) suggested a government-initiatedconversion from meat to novel protein foods (NPFs).STD reasoned that if consumers converted from meat toNPFs, non-sustainable animal husbandry would no longerbe needed. Whereas STD only worried about how toconstruct NPFs with a meat bite, this paper drawsattention to the presumed, but problematic, role forthe government in the execution of the STDsuggestions. Although vegetarians take the credo ``YouAre What You Eat' literally and accuse non-vegetariansof being beasts, a different interpretation is morepromising: eating meat has become a leading thread inmany lifestyles and narratives of self-identity. Sincethe freedom to follow your own lifestyle orconsumptive preferences is a core value incontemporary affluent societies, governmentintervention in the formation and satisfaction ofconsumer preferences for meat dishes is a precariousissue. Hence, NPFs might be interesting for a smallfraction of society, but we had better not expect toomuch from a government-initiated conversion from meatto NPFs as the answer to animal husbandry'sproblems.     

Parental perception of social risk and of positive potentiality of outdoor autonomy for children: The development of two instruments

An important factor that limits children's autonomy outdoors is parental perception of social danger and traffic danger. To obtain quantitative instruments for these dimensions, this work aimed to explore the validity and reliability of three scales. Two of them describe, respectively, problematic aspects of the area of residence linked to traffic and situations of social degradation that could constitute risk factors for the child's psychological and physical safety (Traffic Danger Perception Scale, Social Danger Perception Scale). The third scale investigates parental perception of the positive potentiality of outdoor autonomy for children's maturation and growth. Interviews were conducted with 377 mothers of children between 8 and 10 years of age residing in six different areas in Italy. The results indicated weak reliability of the Traffic Danger Perception Scale, which requires further investigation, and they confirmed the reliability and the construct validity of the Social Danger Perception Scale and the Perception of Positive Potentiality of Outdoor Autonomy for Children Scale. The perception of social danger was higher in mothers who live in larger urban contexts and who have more personal fear of crime and a lower sense of community. The positive perception of children's autonomy of movement was higher among mothers who live in greener areas, who have a greater sense of community and who have more neighbourhood relations.     

并联三自由度运动平台动力学分析

本文由三自由度并联机构的结构入手,介绍了一种一平移两转动的三自由度运动模拟平台,此平台通过改变三个可伸缩的支撑杆的长度来实现模拟平台的特定位姿。应用拉格朗日方程建立动力学模型,分析了机构的结构参数与驱动力的关系,为机械结构设计提供了依据。