Compost bedded pack dairy barn management,performance, and producer satisfaction

The objective of the research was to characterize herd performance, producer satisfaction and recommendations, and management practices used by compost bedded pack (CBP) managers in Kentucky (42 farms and 47 CBP facilities). Farms were visited between October 2010 and March 2011. A random selection of cows housed solely in the CBP were scored for locomotion and hygiene. Changes in monthly Dairy Herd Improvement Association performance records, including milk production, SCC, reproductive performance, and daily bulk-tank somatic cell count after moving into the CBP were analyzed using the MIXED procedure of SAS (SAS 9.3; SAS Institute Inc., Cary, NC). The GLM procedure of SAS (SAS 9.3) was used to develop models to describe CBP moisture, CBP temperature at 20.3 cm, and mean herd hygiene. Producers provided 9.0 ± 2.2 m² of pack space per cow (n = 44). Barns constructed with an attached feed alley cost $1,051 ± 407 per cow (n = 40). Barns constructed without an attached feed alley cost $493 ± 196 per cow (n = 13). Kiln-dried shavings required 0.05 ± 0.04 m³ of bedding per cow per day (n = 15). Green shavings required 0.07 ± 0.06 m³ of bedding per cow per day (n = 12). The most-frequently cited benefits of the CBP included cow comfort (n = 28), cow cleanliness (n = 14), and the low-maintenance nature of the system (n = 10). Increased stirring frequency, stirring depth, and ambient temperature increased pack temperature, measured at 20.3 cm below the CBP surface. Increased stirring depth, pasture-adjusted space per cow, and drying rate decreased CBP moisture. Mean herd locomotion and hygiene scores were 1.5 ± 0.3 (n = 34) and 2.2 ± 0.4 (n = 34), respectively. Increased 20.3-cm depth CBP temperature and ambient temperatures improved mean herd hygiene. Bulk-tank somatic cell count decreased from the year before to the year after moving into the CBP barn (323,692 ± 7,301 vs. 252,859 ± 7,112 cells/mL, respectively) for farms using the CBP barn as the primary housing facility (n = 9). Daily milk production, collected from monthly Dairy Herd Improvement Association tests, increased from before moving into the CBP barn to the second year after (29.3 ± 0.3 vs. 30.7 ± 0.3 kg, respectively) for farms using the CBP barn as the primary housing facility (n = 8). Calving interval decreased from the year before to the second year after (14.3 ± 0.1 vs. 13.7 ± 0.1 mo) moving into the CBP barn for farms using the CBP as primary housing (n = 8).     

浅谈压缩空气的无菌处理

在化工,食品以及药品发酵生产中,所有发酵菌均需消耗氧气,而工业生产中通常采用空气作为氧源,由于空气中含有各种微生物,因此在实际生活中,须对空气进行净化处理。本文结合工程实例,讨论了压缩空气净化处理过程中应注意的几个关键过程。     

65Nb基体钢固体渗碳及淬火工艺

研究了固体渗碳温度、渗碳时间、淬火加热温度和保温时间、回火温度等对６５Ｎｂ基体钢硬度和韧性的影响。结果表明，适宜的工艺为９２０℃×４ｈ固体渗碳，１０８０℃×２５ｍｉｎ加热淬火，５６０℃回火。     

基于STM单片机的智能锂电池组平衡充电器设计

锂电池组均衡充电是动力电池使用技术的重要组成部分,平衡充电技术的应用直接影响电池组的性能与使用寿命。文章设计了一种基于STC12C5A60S2单片机的锂聚合物电池组平衡充电器。该智能平衡充电器能够对小容量的单体电池起到保护作用,而且不影响其余单体电池继续充电,最终实现电池组储能最大化。     

涤纶短纤维纺丝组件的使用与异常丝控制

简述了纺丝组件的结构、作用,探讨了纺丝异常丝的形成,指出熔体杂质含量高、黏度大、纺丝温度低时组件的升压速度快,注头丝、浆块类异常丝与组件相关,其控制要从组件更换、喷丝板面硅修整、组件拆装、清洗规范操作、喷丝板镜检及部位管理着手。     

新型粘胶短丝喷丝组件的设计

为了解决目前常用粘胶短丝喷丝组件反应时间延长、纺丝速度减慢和纺丝产量降低的问题,分析了粘胶短丝喷丝组件的结构及存在问题,设计出一种新型粘胶短丝喷丝组件.该组件喷丝板上用于安装喷丝帽的孔采用了圆环形排布,克服了原结构中梅花排布形式的缺点,组件中间可以输送凝固浴液,保证了凝固浴液与原液的充分接触,缩短了反应时间,提高了纺丝速度和产量.指出:该新型粘胶短丝喷丝组件对于一些特种纤维湿法纺丝机喷丝组件的设计具有非常重要的参考价值,今后,国产粘胶短丝机应在精度、稳定性和可靠性方面下功夫.     

Interface properties and phase formation between surface coated SKD61 and aluminum alloys

The intermediate phase formation and surface protection effects between SKD61 die mold alloys and aluminum alloys were investigated during a simulated die-casting process. The surface coatings of SKD61 alloy were carried out via Si pack cementation coatings at 900 °C for 10 h and the -FeSi phase formed. When the coated SKD61 alloy was dipped in the liquid aluminum alloy (ALDC12), the surface coated SKD61 alloys showed better surface properties compared with uncoated SKD61 alloys, i.e., the intermediate phases (FeSiAl compound) were not produced for the coated SKD61 alloy. The coating layer of -FeSi served as a diffusion barrier for the formation of FeSiAl compounds.     

Formation and Microstructural Characterization of Silicon-modified Aluminide Coating on Nickel-based Superalloy IN738LC

ALUMINIDE COATINGS are used extensively forprotecting gas turbine hot section components due totheir high oxidation resistance and low capital cost.However,for some application,their properties must bemodified by adding elements such as Cr,Si and Pt tomeet high performance gas turbines requirements[l,2].Although silicon is less efficient as a protective scaleformer than chromium and aluminum,silicon-modifiedaluminide coatings,have shown better hot corrosionresistance(specially to type …     

15MnV钢预加涂层粉末渗硼的研究

探讨了１５ＭｎＶ钢预加涂层强化剂固体粉末渗硼工艺。试验结果表明，预先加涂剂于１５ＭｎＶ钢表面可明显强化渗硼过程，渗硼层致密均匀，连续性好，渗硼层的耐磨、耐蚀性能有明显提高。