The Kinetics of Electrode Reactions: Part II—Mass Transfer and Mixed Control

The modes of mass transport to and from electrode surfaces are considered and it is seen that the rate of reactant supply is often a rate determining step in electrochemical reactions which occur in metal finishing. Complete mass transport control is characterised by the limiting current for a reaction and expressions are developed which relate this parameter to reactant concentration and electrode/electrolyte velocity. In many cases, reaction rates are governed partially by mass transfer and partially by electron transfer. This, “mixed control” case is also considered by means of current versus potential curves and the types of overpotential involved.     

Application of aeration sand filling,squeeze balance control and synchronised pattern drawing to flaskless moulding process

Abstract

In recent years, global warming and environmental deterioration problems have drawn public attention. There is an ever increasing demand for production equipments in foundries that are more human friendly and environmentally cleaner. To meet such needs, a new type green sand moulding machine employing 'aeration' sand filling process has been developed. In order to make further improvements in moulding performance, new technologies, squeeze balance control and synchronised cope and drag pattern drawing technology, applied in squeezing and mould stripping process of the flaskless moulding equipment has been developed. Adoption of the squeeze balance control system achieves uniform mould strength and prevents distortion of pattern plates by automatically controlling the squeeze pressure applied to the cope and drag moulds in the squeeze process. This optimises the squeeze pressure according to the shape of the pattern. In this study the effectiveness of these technologies was proved by executing performance tests with an actual machine.     

GREEN FUNCTION在齿轮箱故障诊断中的运用

为了找出齿轮箱故障的定量规律,通过对齿轮箱的振动信号的测试及分析,发现ＧＲＥＥＮＦＵＮＣＴＩＯＮ对齿轮箱故障的诊断行之有效,并且成功地找出了Ｇ１０、Ｇ１０′等齿轮箱故障的定量诊断参数．     

Tack and green strength of brominated isobutylene-co-p-methylstyrene and its blends

The tack of uncrosslinked gum and filled brominated isobutylene-co-p-methylstyrene (BIMS) was examined as a function of time using the 180° peel geometry. The tack strength showed a 1/4th power dependence with respect to time. The BIMS showed marginally lower tack strength than its non-brominated precursor (IMS). The addition of fillers to the BIMS increased the tack strength as compared to the gum rubber. With increasing filler loading, the tack strength increased up to a certain contact time. A good adhesion between BIMS and ethylene propylene diene terpolymer elastomer (EPDM) was observed due to their similar solubility parameters, whereas adhesion between BIMS and natural rubber (NR) was low. Autohesion studies of different blends of BIMS with EPDM and NR revealed that 70 : 30 BIMS : EPDM and 30 : 70 BIMS : NR blends showed higher tack strength than their constituent polymers. The results could be explained in terms of green strength and compression creep measurements.     

Consolidation and green body characteristics of gelcast metallic powder

Abstract

A preliminary study concerning the compaction of metallic powder was carried out in order to investigate a rarely explored route in powder metallurgy, to form complex geometry parts, known as gelcasting. Green bodies produced with as supplied stainless steel powder showed a tendency to form foam, which affected the surface finishing. The mechanical behaviour of green compacts was also affected by the processing additives present in the metallic powder. Organics in the as supplied powder were removed by thermal treatment at 500°C and additional samples were produced. Although no difference in green density was observed, these samples displayed better surface finish and mechanical characteristics, as a result of improved adhesion between the polymer network and particle surface. The results showed that the gelcasting process is able to produce green parts suitable for subsequent thermal treatment.     

Influence of raw material particle size on quality of pellets

Abstract

Pellet plant (4·2 MPta capacity) of JSW Steel Ltd imports iron ore fines from different mines to produce pellets for its Corex and Blast Furnace plants. The pelletisation process involves drying the ore fines to reduce the moisture content to less than 1%, grinding in open circuit ball mills to get required fineness. To produce good quality of pellets certain additives are important and limestone is employed for modifying the pellet basicity. Iron ore fines of ?10 mm size and limestone are ground together in a ball mill to get sufficient fineness for the balling process. However, as limestone is harder than iron ore fines the + 100 mesh size limestone particles is higher than required and not all the limestone is fully consumed in the reaction for melt formation. Microstructural studies were conducted under a Leica DMRX polarized microscope at different level fineness (?325# ? 56, 58 and 60%) to investigate its effect on the pellet quality. The cold crushing strength of the pellet improved from 203 to 220 kg p^?1 with increase in fineness. With increase in percentage of ?325# particle size in the ground product RDI of the pellet decreased from 13·8 to 11·9% with increased melt formation from 5 to 9%. With increase in fineness ?325# from 56 to 60% the 150 to 500 μm size pores decreased from 51·8 to 13·6%.     

LDPE工艺颗粒水系统粉尘产生的分析及应对

颗粒水系统水是高压装置挤压造粒的重要水系统,担负冷却、传输聚乙烯产品颗粒的作用,本文参照高压装置开车多年来颗粒水系统粉尘处理措施,以实际操作实际加以分析。     

Internet路由器的AQM策略的研究与分析

分析了几种典型及最新提出的AQM策略算法,并比较了各种策略算法的优缺点,同时对AQM的拥塞指示方式进行了分析,最后给出了几种AQM策略的实验分析结果。