A Cross-Cultural Investigation of the Efficacy Beliefs of South Asian Immigrant and Anglo Canadian Nonimmigrant Early Adolescents.

The author explored the mathematics efficacy beliefs of 270 South Asian (Indo Canadian) immigrant and Anglo Canadian nonimmigrant Grade 7 students. Self-efficacy beliefs strongly predicted mathematics performance for both cultural groups, but there were differences between the 2 groups in the sources of self-efficacy, the predictiveness of the secondary motivation variables, and the vertical dimensions of individualism and collectivism. It is argued that the Indo Canadian students are more vertical or hierarchical than the Anglo Canadian students and that comparison with others strongly influences their motivation beliefs and the formation of their efficacy beliefs. Self-efficacy in some cultures may be more other-oriented than is typically seen in Western cultures. A caution against generalizing about Asian populations is given, and implications for school settings are explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of submerged arc welding parameters on microstructure of SA516 steel weld metal

Abstract

The influence of submerged arc welding (SAW) process parameters on the microstructure of SA516 grade 70 steel weld metal (WM) was investigated in the present work. Steel plates of 17 mm thickness were submerged arc welded using welding currents of 700–850 A and welding speeds of 5·3–15·3 mm s^?1. The morphologies and volume fractions of the various ferrites in the WM were studied using optical microscopy and the morphologies and chemical compositions of the WM inclusions were examined using scanning electron microscopy and energy dispersive X-ray spectrometry. The results showed that the WM grain structure coarsened but the grain width of prior austenite grains decreased with increasing heat input. Also, the proportion of acicular ferrite (AF) in the WM increased initially, while the volume fractions of grain boundary ferrite and Widmanstätten ferrite decreased with increasing welding current. However, with further increasing the welding current above 800 A, less AF was produced. The weld nugget area decreased with increasing welding speed at all currents, but did not affect the amount of AF produced.

Au cours de ce travail, on a examiné l’influence des paramètres du procédé de soudage à l’arc sous flux en poudre (SAW) sur la microstructure du métal soudé (WM) de l’acier SA516, Gr. 70. On a soudé à l’arc sous flux en poudre des tôles d’acier de 17 mm d’épaisseur en utilisant des courants de soudage de 700 à 850 A et des vitesses de soudage de 5·3 à 15·3 mm s^?1. On a étudié la morphologie ainsi que la fraction volumique des diverses ferrites du WM en utilisant la microscopie optique et l’on a examiné la morphologie ainsi que la composition chimique des inclusions du WM en utilisant la microscopie électronique à balayage (SEM) et la spectroscopie à dispersion d’énergie (EDS). Les résultats ont montré que la structure de grain du WM grossissait mais que la largeur de grain des grains antérieurs d’austénite diminuait avec une augmentation de l’apport de chaleur. Également, la proportion de ferrite aciculaire (AF) dans le WM augmentait initialement, alors que les fractions volumiques de ferrite des joints de grain (GBF) et de ferrite de Widmanstatten (WF) diminuaient avec l’augmentation du courant de soudage. Cependant, avec une augmentation supplémentaire du courant de soudage au-dessus de 800 A, moins de ferrite aciculaire était produite. La région du noyau de soudure diminuait avec une augmentation de la vitesse de soudage à toutes les valeurs de courant, mais la quantité d’AF produite n’était pas affectée.     

E36高强度船板钢的开发

介绍了湘钢宽厚板厂开发E36高强度船板钢的主要技术思路和工艺路线。通过合理的成分设计、钢水纯净度控制和控轧控冷工艺,得到钢质纯净、组织细化的E36级船板,使其具有优异的综合力学性能,满足了船级社的认证要求。     

提高金堆城选铜指标的实践

介绍了近３年来金堆城华光实业总公司有色金属选矿厂采取技术措施,提高选铜指标的生产实践经验。     

首钢京唐低硅低镁烧结技术的研究与应用

为了进一步改善5 500m~3特大型高炉精料入炉水平,首钢京唐炼铁作业部在停配白云石熔剂实现自然镁烧结的基础上,结合相关烧结杯试验做了微观组织结构研究。根据生产实际,通过采取优化配矿结构以及调整过程控制参数等措施,逐步降低烧结矿SiO_2与MgO质量分数生产低硅低镁烧结矿。通过低硅低镁烧结技术的应用,首钢京唐炼铁作业部在改善烧结矿品位稳定强度、粒度的基础上保证了入炉精料水平,并取得了较好的效果,为首钢京唐5 500m~3特大型高炉提高综合入炉品位、降低渣比以及喷煤降焦创造了良好的原料条件。     

一等标准铂电阻温度计在（0～419.527）℃温区检定的不确定度评定

介绍了一等标准铂电阻温度计的在锌凝固点检定的不确定度的评定方法,包括Ａ类标准不确定度及Ｂ类标准不确定度的确定,标准不确定度的合成及有效自由度的计算,并按误差传播公式计算出了在各温度点的扩展不确定度及包含因子。     

首钢低温高韧性系列船板的研发

介绍了首钢采用低碳成分设计和TMCP工艺开发E级船板的关键控制技术和工艺路线。通过低碳、Nb、Ti微合金化的成分设计、控制钢水纯净度、采用合理的两阶段控制轧制及控制冷却工艺,得到钢质纯净、组织细化的E级船板钢。试制结果表明,拉伸性能、Z向性能、冷弯性能、低温冲击韧性等各项力学性能良好,产品质量完全符合GB712—2000国家标准要求,并达到船级社生产认证要求水平。     

银山铅锌矿现场矿石管理的经验

为充分利用有限的铅锌资源,稳定铅锌供矿品位,降低生产成本,提高矿山经济效益,经过多年配矿实践,总结出一个普通的稳定供矿品位技术管理模式即回采作业地质指导→现场矿石管理(井下出矿管理+配矿)→稳定供矿品位,此管理模式具有一定的推广应用价值.     

Prediction and quality control of the melt index during production of high-density polyethylene

In polyolefin processes the melt index (MI) is the most important control variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the 1 ^st -order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. The virtual sensor model developed based on the estimation scheme was combined with the virtual on-line analyzer (VOA) to give a quality control system to be implemented in the actual HDPE plant. From the application of the present control system, significant reduction of transition time and the amount of off-spec during grade changes was achieved