使用改进聚合物提高轮胎寿命和节油性能

过去10年中，原配轮胎的滚动阻力和抓着性能不断得到改善，以满足汽车公司越来越严格的要求。由于各种胎面用聚合物的不断发展，才能实现上述改善。     

Scales to measure parents and caretakers satisfaction with the food and nutrition component of Child care Centers

Two Likert-type scales for measuring parents' and caretakers' level of satisfaction with the food and nutrition services offered at childcare multi-centers in a peri-urban community in Caracas, were developed and validated. An intentional sample of 20 parents and caretakers were interviewed within the naturalistic-constructivist perspective, to capture their perceptions of distinct aspects of the food and nutrition components of the program. Categories emerged from the interviews that served to construct the items for two scales that measure level of satisfaction of parents and caretakers with the food and nutrition aspects of the program. To validate the scales, they were applied to 73 parents and 32 caretakers. Factor and multiple components analysis showed that overall, the scales explained 61% and 69% of the variation in level of satisfaction of parents and caretakers respectively. Confiability measured with Alpha Cronbach coefficient was 0.74 and 0.77 for parents' and caretakers' scales respectively. These results reveal scales that have content validity and good reliability. Besides, the scales detect specific aspects of the food and nutrition service that should be reinforced or modified, to make the Child-care Centers program more effective and efficient. External validation of the scales is recommended, since they provide an instrument capable of capturing useful information for monitoring and evaluating the Child-care Centers program nation-wide, from the perspective of program managers and parents of program users.     

iWo.Fashion此间的明媚少年

阔别重逢的第一缕春光让慵懒的瞳孔紧张地收缩,绚烂的男装世界也终于开始了纷乱的演绎,或是把深沉的色调流畅地铺开。     

痕量工程

多年来,而且在越来越大的范围内,工程人员曾经和存在有很低浓度的物料的物系所产生的问题打交道。 有时候这些物料是污垢物,它们导致不合格的产品或危险的场面(例如,聚合物中的“鱼眼”,废气中的一氧化碳)。在别的场合,这些物料具有很高的实际价值,在经济上有理由把它们浓缩并回收(例如,从沙里回收金,重氢的生产)。     

IR在胎面胶中的应用

具有高含量3，4-结构的IR能特别有效地提高高性能轮胎的湿抓着力。因此，可以通过调整炭黑和BR用量来提高轮胎的磨耗和滚动阻力性能，同时保持优异的湿抓着性能。     

Co—SnO_2—CaO—SiO_2基陶瓷色剂

借助于X一射线衍射分析和紫外线可见分光光度法研究了CO—SnO_2—CaO—SiO_2基陶瓷色剂的结构,证明其结构中的发色阳离子为Co(Ⅱ)。通过X一射线衍射分析CasnSiO_5在低于1100℃温度下的组成,通过测定试样的漫反射率确定了处在八面体中的可见发色阳离子Co(Ⅱ)。与此同时,研究了试样在1300℃/1h和1350℃/2h条件下的组成,引入硼酸作为矿化剂降低了合成物的合成温度。最后对该系合成物作为陶瓷色剂可能性进行了试验。     

滴流床反应器:综述(Ⅲ)

<正> 反应器设计:液体分布 对吸收塔中的液体分布已有广泛的研究。这些资料用于滴流床中具有其局限性,因为操作条件通常不同。因此,以下讨论只限于滴流床研究。     

Influence of maize kernel hardness on flour hydration and cooking properties

Knowledge of the association between cooking properties and endosperm hardness may help nutritionist and processors to select raw materials for preparing maize based food products, particularly those eaten as cooked dispersions. Seven commercial maize cultivars differing in hardness were selected to evaluate endosperm hardness on the kernels and some characteristics such as composition and hydration and cooking properties on the grits obtained from those maizes. Results show that the differences in endosperm hardness (directly related to grits protein content) can explain the differences in swelling and amylographic consistencies values. Cultivars with the hardest endosperm show the lowest values at high temperature. They also show the lowest amylographic consistencies. On the other hand softer endosperms present the highest swelling power and the highest amylographic consistencies. These differences are attributed to the restriction for starch swelling caused by the protein matrix. Endosperm hardness measurements and swelling power at 95 degrees C, can be useful to select cultivars that are going to be used to prepare maize based foods like atoles, polenta, etc.     

异向旋转双螺杆挤出机的发展前景

本文通过分析螺杆在不同区段的几何特征及其对相应加工阶段的影响对平行和锥形双螺杆挤出机进行了全面的比较。