三元乙丙橡胶在简单口型中的正向挤出分析及逆向口型设计

采用Polyflow软件、Bird-Carreau纯黏性模型对三元乙丙橡胶(EPDM)在简单口型(正三角形、矩形)及其流道中进行了正向挤出过程模拟和逆向口型设计分析,并加工了相应的口模,通过挤出机进行了挤出试验,试验数据与模拟预测结果比较接近,逆向计算所得到的口型比较合理。结果表明,可以采用Polyflow软件、Bird-Carreau纯黏性模型近似地模拟计算EPDM的正向挤出过程和逆向口型设计。     

基于Imageware和MoldfloW的后视镜逆向设计与注塑成型模拟分析

简述了逆向工程的设计过程和方法以及Moldflow在注塑成型分析中的应用.利用Imageware软件对测量设备得到的摩托车后视镜点云数据进行处理、曲线拟合与曲面重构.然后将反求模型导入Moldflow/MPI软件中进行注塑模拟仿真及工艺优化,并进一步优化模具结构指导生产.通过逆向设计和Moldflow结合,可以快速获得高质量的塑件产品,从而提高产品和模具的研发速度.     

复杂曲面逆向设计及模具和注射工艺优化

以海豚型按摩器的上壳制品为例,引入逆向设计技术,通过三维扫描仪获得已有样品的点云数据,利用Imageware和Geomagic软件对点云进行处理并重构曲面,并在此基础上进行必要的创新再设计,得到所需要产品的三维设计图.将逆向设计模型导入模流分析软件Moldflow/MPI中并设计出浇注系统和冷却系统,通过注射数值模拟,...     

Polyflow逆向挤出功能在异型材口模设计中的应用

比较了Polyflow用于挤出口模数值模拟的两种方法,即逆向挤出与给定口模的数值模拟,并介绍了Polyflow逆向挤出功能的基本过程;然后以一个典型十字型异型材的挤出口模设计为例,详细介绍了如何用Polyflow软件的逆向挤出功能对口模形状和尺寸进行数值预测。     

挤出胀大逆向求解技术在多腔精密医用导管口模设计中的应用

口模截面形状的设计是多腔精密医用导管挤出成型中的一个难点,采用Polyflow软件逆向求解挤出胀大过程的功能,分析双孔异径和双腔异型两类典型多腔精密医用导管的逆向求解过程,给出了生产理想制品所需的口模截面形状.同时针对多腔精密医用导管在成型过程中内腔存在微量气压这一特征,逆向求解了在微量气压作用下的口模截面形状,为实际设计过程中机头口模的确定和修改提供了依据.此外,也对其它4类典型的多腔精密医用导管进行了逆向分析,给出了无气压作用下的口模截面形状.对于多腔精密医用导管机头口模设计具有较高的参考价值.     

基于逆向技术医疗外固定支具的设计

现有外固定支具比较笨重,不美观,不透气,与患部不能很好贴合,对康复效果造成影响。采用逆向技术,通过三维扫描仪扫描采集患者患部,获取三维点云数据,对点云数据进行处理得到三维数据模型。利用UG软件进行正向建模设计,根据医生及患者的要求设计出符合人体工程学特性的外固定支具。将逆向与正向建模设计相结合,为个性化医疗外固定支具设计提供一种高效的方法。     

Polyflow逆向挤出功能在T型材口模设计中的应用

介绍Polyflow模拟软件的结构、特点及其在聚合物加工过程中的应用,以T型材挤出口模设计为例,建立几何模型、数学模型及有限元模型.通过在Polyflow模拟软件中构建任务并定义各项参数,利用重新生成网格技术,进行数值模拟和分析.详细论述了如何有效应用Polyflow逆向挤出功能对T型材挤出口模进行设计.研究表明:Polyflow逆向挤出功能可以提前预测其变形倾向,提高口模设计的一次性成功率,缩短口模的开发周期,降低成本.     

化工生产中废旧仪表的回收利用方式初探

本文阐述了化工生产企业中废旧仪表的逆向物流的特点,针对国内的废旧仪表逆向回收现状进行分析。并且设计了废旧仪表的回收模式。描述了废旧仪表逆向物流过程在全生命周期的各个阶段标签内容的设计。     

逆向工程在塑料产品及其模具设计中的应用

介绍了一种基于逆向工程技术的塑料产品模具数字化设计方法,分析了塑料产品在逆向造型过程中应遵循的基本原则和要点,然后以某车灯反射器为例对其进行了说明。此过程中,先借助三维激光扫描仪采集了反射器曲面的点云数据,然后利用Geomagic Studio软件进行了数据处理和快速曲面重构,最后将曲面模型导入Pro/E软件中进行反射器的三维模型重建并分模,形成模具型腔。实践表明,此方法能够实现注塑模的快速设计,缩短产品的开发周期,尤其对曲面形状复杂、缺失原始几何数据等产品的设计与制造具有参考意义。     

POLYFLOW在高分子成型加工中的应用研究进展

在聚合物制品外形控制和性能调控过程中,高分子熔体的流动分析对于研究高分子成型工艺至关重要.POLYFLOW软件在高分子成型加工中的应用日渐广泛.本文深入分析了POLYFLOW在挤出、吹塑和热成型等方面的应用,重点介绍了挤出过程中的正向流动仿真和逆向口模设计,最后对POLYFLOW在高分子成型加工中的应用研究方向进行展望...     

5种新型杀菌剂对4种鱼的急性毒性及安全性评价

为评价5种新型杀菌剂的环境安全性,采用半静态法测定了其对4种鱼的急性毒性。结果表明,氟醚菌酰胺对斑马鱼、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)均大于100 mg/L,对青鳉的LC_(50)(96 h)为35.25 mg/L,其急性毒性均为低毒;氟吡菌胺对斑马鱼、青鳉、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为1.49、0.56、0.35、1.04 mg/L,其对斑马鱼和凤尾鲫急性毒性为中毒,对青鳉和稀有鮈鲫为高毒;苯噻菌胺对斑马鱼、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)均大于100 mg/L,对青锵的LC_(50)(96 h)为88.23mg/L,其急性毒性均为低毒;嘧菌酯对斑马鱼、青鳉、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为106.80、0.44、85.96、4.61 mg/L,其对斑马鱼和稀有鮈鲫急性毒性为低毒,对青鳉急性毒性为高毒,对凤尾鲫为中毒;醚菌酯对斑马鱼、青鳝、稀有鮈鲫和凤尾鲫的LC_(50)(96 h)分别为0.77、0.66、0.51、0.81 mg/L,其对4种鱼急性毒性均为高毒。明确这些药剂的环境安全性对指导其科学使用,保护环境生物均有较大意义。     

Major Trends in Refractories Industry at the Beginning of the 21st Century

An analysis of the present and of the future of the refractories industry is being presented,considering some improtant techincal,economical,human and environmental issues,on a worldwide basis,Refractories still needed as confinement materials to prevent heat and mass transfer losses in many diverse manufacturing industries,and will remain so ,but the main challenges,this industry do need to neet,are to adjust to and overcapacity production ,to cope with new needs of the customers,in particular the “outsourcing“,which is a new custome/supplier rela-tionship being adopted by many of them,and more compet-itive arena.Among the direct consequences,are the need to keep the education world in refractory engineering training aliver and to cope with macro and micro projects to change the image of the Refractories,from a commodity material to a sophisticated “high-tech“ compostie material.Some suggestions are provided in the text.     

Long-term residual value of North Carolina and Queensland rock phosphates compared with triple superphosphate

The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia.     

尿素设备腐蚀的影响因素分析及防腐措施

针对尿素生产的特点,分析了对尿素设备腐蚀的影响因素:介质温度、氨碳摩尔比、水碳摩尔比、氨基甲酸铵溶液浓度、氧含量、硫含量、氯离子含量和介质流速等。提出了正常生产和停车封塔2种情况下的防腐措施。正常生产期间要严格控制如下指标:操作温度、系统的加氧量、硫含量、氯离子含量、氨碳比和水碳比;停车期间要严格控制系统的氨碳比和水碳比,同时根据不同状况来确定停车封塔时间。     

Effect of catalysts in the quality of syngas and by-products obtained by co-gasification of coal and wastes. 1. Tars and nitrogen compounds abatement

The aim of this work is to analyse the possibility of using co-gasification technology to process coal mixed with wastes to take profit of its energy content and at the same time to minimize the environmental impact associated with the use of wastes and to diminish the costs of flue gas treatment. The addition to coal of different types of materials, like: pine based waste, petcoke and polyethylene (PE), was not found to give rise to any operational problems, regarding both the feeding system and gasification process and led to higher energy conversions, however, the gas presented higher tars and hydrocarbons content. Several catalysts were tested, such as, dolomite, olivine, nickel and magnesium oxides, zinc oxides and cobalt and molybdenum oxides. Catalyst action was analysed in tars release and also in ammonia compounds reduction. The presence of catalysts allowed increasing hydrogen release, whilst there was a decrease in hydrocarbons and tars contents. A nickel-magnesium oxide was the catalyst that led to the highest reduction in hydrocarbons and tars. This catalyst also led to the lowest NH₃ content in the fuel gas produced, due to the catalyst efficiency in NH₃ destruction.     

Impact of ammonia fiber expansion (AFEX) pretreatment on energy consumption during drying,grinding, and pelletization of corn stover

Pretreatment and densification of biomass can increase the viability of bioenergy production by providing a feedstock that is readily hydrolyzed and able to be transported over greater distances. Ammonia fiber expansion (AFEX?) is one such method targeted for use at distributed depots to create a value-added and densified feedstock for bioenergy use. However, the pretreatment process results in a high-moisture material that must be dried, further size reduced, and pelletized, all of which are energy-intensive processes. This work quantifies the energy consumption required to dry, grind, and densify AFEX-pretreated corn stover compared to non-pretreated stover and explores the potential of reduced drying as a means to conserve energy. The purpose of this work is to understand whether material property changes resulting from AFEX pretreatment influence the material performance in downstream formatting operations. Material properties, heat balance equations, and a rotary drum dryer model were used to model a commercial-scale rotary drum dryer for AFEX-pretreated corn stover, showing the potential to reduce dryer energy consumption by up to 36% compared to non-pretreated corn stover. Laboratory-measured grinding and pelleting energies were both very sensitive to material moisture content. Overall, the total energy required for drying, grinding, and pelleting amounts to a savings of up to 23 kWh/dry Mg for the AFEX-pretreated material when dried to a low moisture content, equating to up to 0.61 $/Mg savings for gas and electricity. Grinding and pelleting of high-moisture AFEX-pretreated stover was shown to be more costlier than the savings collected through reduced drying. Although the energy and cost savings shown here are modest, the results help to highlight operational challenges and opportunities for continued improvement.     

中国基础磷化工产业现状与展望

以磷肥、黄磷、热法磷酸、三聚磷酸钠、饲料磷酸氢钙等产品为例,阐述了基础磷化工产业现状,针对基础磷化工产品同质化、技术等同化、市场过剩的局面,分析了产生问题的原因。指出基础磷化工必须淘汰落后产能,必须依靠技术进步降低生产成本,实现产品结构的升级与调整;而技术进步的重点在于实现原子经济效益、能源利用和劳动生产效率三者的最大化以及消耗的最小化,要不断开发满足社会需求的新产品。此外,还对相关的政策法规和规章制度提出建议。     

我国现代煤化工产业发展现状及对石油化工产业的影响

介绍了我国煤制油、煤制烯烃、煤制天然气、煤制乙二醇等几种现代煤化工技术及其产业化发展现状,探讨了现代煤化工的资源消耗、CO₂排放及产业发展过程中的相关问题;同时,分析了现代煤化工产能增长对石油化工产业的影响。结论认为,我国石油对外依存度逐年上升,发展现代煤化工是对石油化工的有益补充,是发挥我国煤炭资源优势、保障国家能源安全的重要途径;近年来我国现代煤化工取得快速发展,但总体来说产业发展之路仍在探索之中,需要深入研究、稳步试点、慎重推广。随着我国现代煤化工产能不断释放,其与石油化工的竞争逐渐凸显,石化企业应注重创新驱动,发挥产品差异化优势,同时降低生产成本,与现代煤化工企业实现优势互补、互利双赢。     

提高学生综合与创新能力多种教学方式的探索

以《材料化学》、《复合材料》、《材料现代分析技术》和《材料导论》等专业课为载体,结合高分子科学与工程系科研优势和资源,探索启发式、参与式和专题讨论课等多种教学方式,将其应用到专业课教学中,以提高学生综合与创新能力为目标进行教学研究与实践。在理论课教学上注重思维训练,传授学习方法,提高学生学习自主性;注重课程之间对学生综合能力培养的协同作用。鼓励学生开拓思路,鼓励创新,配合教师完成每个教学环节,由此加深学生对课程知识的理解,有效地提高综合能力。     

Catalysis, a driver for sustainability and societal challenges

Catalysis is an enabling technology to promote sustainability, environment, energy, health and quality of life. This contribution discusses the role of catalysis in achieving these objectives and some of the factors which will drive the changes in catalysis research in the next years, in particular the need to go to more sustainable and modular-design of the chemical processes (F³-factory), the use of biomass and of renewables, including solar energy, and the challenges offered from electrocatalysis. It is also emphasized the need to strength research on catalysis, and some examples of how to overcome fragmentation barriers, particularly in catalysis areas (homo-, hetero- and bio-) and in academy–industry interactions. The need to create a longer term vision and strong collaborations in order to develop a knowledge platform, in order to accelerate the innovation path. Finally, the need to develop new catalytic materials, particularly of tailoring catalyst nano-architectures and develop new catalysts based on the concepts of nanoreactors and catalytic nanofactories are discussed.