Assessment of semi-empirical mass transfer correlations for pervaporation treatment of wastewater contaminated with chlorinated hydrocarbons

INTRODUCTION Chlorinated hydrocarbons, a class of widely used dry-cleaning liquids, industrial organic solvents, and degreasers, increasingly find their way into drinking water sources, thus posing a very serious health and environmental problem (Love and Eliers, 1982). These organic solvents are known for their stability in the environment and cancer-causing po- tency and cannot be effectively and economically eliminated by current conventional treatment tech- nologies. One of the few av…     

A parametric study on the contact stress of half toroidal continuously variable transmission

1. Introduction A toroidal continuously variable transmission (CVT) that uses a traction drive to transmit torque has a vastly larger torque capacity than a conventional CVT. This transmission technology has attracted considerable interest owing to its capability in substantially improving vehicle fuel economy and power performance [1]. The half toroidal CVT transmits torque by means of shear resistance of the traction fluid film taking advantage of the property of the fluid solidificatio…     

遂我心愿

科尔比点这样的乡下小镇因为有福克斯河而充满生机,镇上的路和河流并驾齐驱。一条同名的公路在伊利诺伊州的麦柯亨利山谷间蜿蜒曲折,这其实是科尔比点这个名字的真实来历。这里的房屋四处都有,大多是一些夏天的度假屋或是休闲居所。在路的最尽头,有三间门对门的房屋。三个单身老姐妹住在其中的一间。路的另一边是一间黄颜色的小房子,里面住着她们的大表妹,她已经是个寡妇了。她的邻居是她们的兄弟比尔和他的妻子克里奥。克里奥身上有多处患有硬化症,因此这一对夫妇移居科尔比点寻求一个安静、轻松的晚年。他们万万没有想到,他们来到这个僻静…     

扇国王一个耳光

这天,一个名叫唐唐的男孩突然说:“太不像话了,我一定要扇国王一个耳光!”其它小朋友说:“你疯了?国王有那么多军队,一人吐一口唾沫都能把你淹死!”     

专家型教师教学的原型观

在全国范围的公共教育改革中,成为一名专家型教师(即有教学专长的教师)意味着什么,这已是一个迫切需要回答的问题。如果美国的公共学校要成为英才的中心,就必须大力发展最重要的人才资源(教师)。为了明确发展的方向,我们需要建立一个教学专长的模型。此外,如果要把教师的加薪和提级建立在按功绩而不是按资历的基础上,也需要一个教学专长的模型,通过这个模型我们可以得到一些区分出擅长教学的教师和仅有教学经验的教师的行为标准。     

Moral Education of Youths in the Information Age

In Chinese societies, moral education has always been considered the most essential component of education because the nurturing of moral persons is the prime function of schooling. The implementation of moral education has relied on the inculcation of values that reflect moral ideals. The emergence of the Information Age, with a plethora of information and ideas being disseminated instantly through informational technologies, has altered the educational landscape of the world and challenged the conventional approach to moral education. Given this context, we argue that it is important for Chinese educators to find an alternative approach to moral education that can embrace the new realities of our networked world. In this approach, lofty moral ideals should give way to simple and easily understood concepts such as respect, information and ideas in the ＂cyber world＂ should be exploited rather than shunned, and the genuine interests of children and youths should form the basis of moral education that is at once relevant and enlightening. In proposing this approach to moral education, we also assume that moral educators in Chinese societies, which include school teachers, parents, and organizers of nonformal education programs, would endeavor to understand the complex world of cyber realities and devise feasible ways to suit contextual educational needs.     

20世纪的中国史学：对其背景和发展过程的评论

一在中国史学的现代化进程中 ,起作用的主要有三个因素。第一个因素是时势 ,因为时势变了 ,对过去历史的解释就得随之而改变。第二个因素是史学变革的手段 ,这可以从中国史学的自身传统中获得。第三个因素就是外来文化的影响 ,这种影响是通过近代西方史学以及其强劲的日本支脉而获得的。就史学领域本身来说 ,传统史学也是中国史学现代化的一个基础。更为重要的是 ,传统史学著作都是中国式的 ,故而更容易为人们所接受。梁启超在《中国历史研究法》一书中 ,就曾引用一系列中国古代批评旧思想的学者言论 ,借以说明他倡导的有悖于传统的历史观念…     

谁动了我的奶酪?

这个奶酪是什么? 在我们的生命中,我们都有一些想获得的东西--一份工作、一段关系、金钱、房子和家、自由、健康、获得认同、精神上的平静,或者是我们喜欢的活动,像是打高尔夫或是阅读。在这个故事中,"奶酪"是一种隐喻,代表了我们想要的这些东西,也就是吸引着嗅嗅、匆匆、哼哼和吱吱的这些东西,这些东西使他们快乐,充实了他们的存在。我们每个人对于我们的奶酪是什么都有自己的见解,我们追求它们,因为我们相信这些东西能使我们快乐。     

Conservation laws for energy and momentum in curved spaces

In arbitrary Riemannian 4-spaces, continuity equations are constructed which could be interpreted as conservation laws for the energy and momentum of the gravitational field. Special attention is given to general relativity to obtain, of natural manner, the pseudotensors of Einstein, Landau-Lifshitz, Mller, Goldberg and Stachel, and also the conservation equations of Komar, Trautman, DuPlessis and Moss.