高炉煤粉球磨机大修

介绍了球磨机大修施工过程、经验和安装工艺技术要求，工程确保了施工安全，有效地恢复了球磨机的精度要求和功能。     

108m~3聚合釜热水入料扩能改造总结

介绍了108 m3聚合釜热水入料的改造方案,改造后生产周期缩短了80～90 min,有效提高了PVC产量。     

Controlled feeding of lignocellulosic substrate enhances the performance of fed-batch enzymatic hydrolysis in a stirred tank reactor

High initial viscosity in the high-solids (>15% (w/v)) enzymatic hydrolysis of lignocellulose is problematic especially in stirred tank reactor concepts. One potential way to avoid the high viscosity is the fed-batch feeding of lignocellulosic material to the reactor. In the current study the hydrolysis of filter paper with final concentration of 19.1% (w/w) was evaluated with different fed-batch procedures. Feeding was based on visual observation, stepwise feeding and the power requirement of the stirrer motor. All the fed-batch procedures resulted in similar yields within 30 h (47–49%) which were higher than with the batch process in similar reactor (38%). However, the mixing behavior was superior in the power based feeding as the instantaneous power of the stirrer motor was kept lower (<10 W) than in other fed-batch procedures (>20 W). The power controlled procedure was further evaluated with different enzyme doses, tip speeds and the power levels of substrate feed. Further study showed that the power controlled feeding is applicable also to other hydrolysis and mixing conditions if power levels of substrate feed are set correctly. Higher (15 FPU/g) enzyme dose caused shorter feeding time (3.0 ± 0.5 h) and lower energy consumption during the feeding period (14 ± 3 Wh) compared with lower (5 FPU/g) enzyme dose (7.0 ± 1.3 h and 33 ± 5 Wh, respectively). The tip speed and the power level of substrate feed had fewer effect on these factors. The performance of the hydrolysis process can thus be enhanced by the substrate feed controlled by the power of the stirrer motor.     

Effect of prepartum grouping strategy on displacements from the feed bunk and feeding behavior of dairy cows

The objective of the current study was to determine whether providing stable pen management affected displacements from the feed bunk and feeding behavior of prepartum dairy cows. Two hundred and twenty-four nonlactating Jersey primiparous and multiparous cows were enrolled in the study. The 2 treatments were all-in-all-out (AIAO; 44 cows were moved into the close-up prepartum pen as 1 group, with no additions during the 5-wk repetition) or traditional (TRD; with weekly entrance of new cows to maintain a pen density of 44 cows). Cows (253 ± 3 d of gestation) were balanced for parity and projected 305-d mature-equivalent milk yield and assigned randomly to either AIAO or TRD treatments. At enrollment, cows with a body condition score <2 or >4 (1–5 scale; 1 = emaciated and 5 = obese) or with a locomotion score >3 (1–5 scale; 1 = normal gait and 5 = severely lame) were not included. Displacements from the feed bunk were measured weekly for both treatments when TRD cows were moved into the close-up pen (d 0) and additionally on d 1, 2, 3, and 7 for 3 h after fresh feed delivery. A displacement rate was created to take into account differences in stocking density throughout the experiment. Displacement rate was calculated as the number of displacements divided by the number of cows in the pen at that time. Feeding behavior was measured using video 10-min scan sampling for 24-h periods at d 0, 1, 2, and 7. Displacements and feeding behavior were recorded for all 5 wk of each repetition. Treatment × week interactions were detected for number of displacements and displacement rate. The TRD treatment had more displacements from the feed bunk than AIAO in wk 1, 3, and 5, with no differences in wk 2 and 4. Similarly, the TRD treatment had a greater displacement rate than the AIAO treatment in wk 1 and 5, with a tendency in wk 3. No differences between the treatments were detected in wk 2 and 4. A treatment × week interaction existed for feeding time. Cows housed in the AIAO treatment had longer average feeding times in wk 2 with a tendency in wk 3, but spent 39 fewer minutes eating than those in the TRD treatment during the wk 1 of the study. Housing prepartum close-up cows with stable pen management reduced displacements from the feed bunk and altered average daily feeding times.     

承钢精粉供应模式探索

承钢探索合理的精粉供应模式,解决了原料场地储存能力小,使用精粉矿点多、成分复杂的不利影响。通过精粉分类、前延管理、系统监控等手段,实现了混合料质量稳定,为烧结系统提供质量稳定的混合料。在目前严峻的市场条件下,探索以管理手段代替占用大量资金的传统料场管理模式的可行性。     

Study on spiral wall thickness unevenness of thin- walled tubes rolled by Assel rolling mill

In view of the internal thread defect of thin- walled tubes rolled by Assel 3- roll skew rolling mill, Assel cross- rolling process of X20Cr13 steel tube with typical specification of ??160mm??6. 5mm was numerically simulated by using 3D finite element analysis software Simufact. The influences of different mandrel movement modes, feeding angles and rolling strip profiles on the depth of internal thread were studied. The results show that the depth of the internal thread of steel tube rolled by the full floating mandrel is the most shallow, the second is that of the fixed mandrel and that of the pull mandrel is worst, and it will be gradually deepened when the feed angle increases; the hyperbolic rolling strip is more conducive to controlling the internal thread depth of the rolled tube. Under the condition of hyperbolic rolling strip, the amount of twist deformation of the rolled tube in the rolling process is about 35% smaller than that of the straight rolling strip.     

具有全自动（半自动）进出料等功能最新型真空冷冻干燥机研发报告

主要介绍了上海千山远东制药机械有限公司最新研发的具有全自动（半自动）进出料功能真空冷冻干燥机的概况，从四个方面描述了在功能、质量上的提高，使国产真空冷冻干燥机真正符合新版GMP要求。     

The benefits of planar circular mouths on suction feeding performance

Suction feeding is the most common form of prey capture across aquatic feeding vertebrates and many adaptations that enhance efficiency and performance are expected. Many suction feeders have mechanisms that allow the mouth to form a planar and near-circular opening that is believed to have beneficial hydrodynamic effects. We explore the effects of the flattened and circular mouth opening through computational fluid dynamics simulations that allow comparisons with other mouth profiles. Compared to mouths with lateral notches, we find that the planar mouth opening results in higher flow rates into the mouth and a region of highest flow that is positioned at the centre of the mouth aperture. Planar mouths provide not only for better total fluid flow rates through the mouth but also through the centre of the mouth near where suction feeders position their prey. Circular mouths are shown to provide the quickest capture times for spherical and elliptical prey because they expose the prey item to a large region of high flow. Planar and circular mouths result in higher flow velocities with peak flow located at the centre of the mouth opening and they maximize the capacity of the suction feeders to exert hydrodynamic forces on the prey.