New versus old broiler housing technology: Which leads to greater profit?

The method of matching samples was used to compare the costs and returns associated with broiler housing technology using Agricultural Resource Management Survey data for 2006 and 2011. Farms with housing that included tunnel ventilation and evaporative cooling cells (new technology) were compared with farms with housing that did not include this technology (old technology). Gross farm income, total variable expenses, and total fixed expenses were higher for the new technology farms for both years. New technology farms had greater income over variable expenses and net cash farm income in both years.     

锅炉省煤器改造的简化计算

生产实际中，由于锅炉设计或者煤质等问题，造成锅炉结焦和积灰等问题，为解决这种情况，许多厂家不得不采取措施对现有的锅炉进行局部改造，探讨了解决锅炉省煤器积灰问题的一种方法，如何利用简单的计算方法替代繁琐的热力学公式进行计算，做好改造前的准备工作，以达到预期的效果。通过对实际改造后的省煤器进行数据验证，结果非常好。     

鹿角灵芝的诱导孔原基诱导技术

研究了开设诱导孔的方式诱导鹿角灵芝(Ganoderma amboinense)形成原基的方法,结果表明:鹿角灵芝在菌丝完全发满菌包或发满菌包至3/5以上时可以通过在菌包肩部下方1～2cm处开2个诱导孔诱导原基形成,这种诱导方法较常规方法可使菌丝未发满的菌包提前20～30d形成原基;还可将原基形成率从52%提高至82%～94%,增产55%～186%;使用诱导孔处理未完全发满菌丝的菌包还可加速菌丝发满菌包、加强菌丝长势,增强子实体抗病能力。     

接装纸涂胶量对卷烟滤嘴通风率的影响

为使接装纸透气度及滤嘴通风率在指标范围内保持稳定,采用单因素试验法,研究接装纸涂胶量对接装纸透气度及滤嘴通风率的影响,以及接装纸涂胶量随接装机运转速度和接装纸包角的变化关系。结果表明,1接装纸涂胶量对接装纸透气度及滤嘴通风率的影响显著;2接装纸涂胶量随接装机运转速度的提高而减少;3接装纸涂胶量随接装纸包角的增大而增加。并建立了接装纸涂胶量与接装机运转速度和接装纸涂胶量与接装纸包角之间的函数关系,经过分析计算得到了接装纸包角与接装机运行速度的数学模型。当接装机运转速度发生变化时,该模型可通过调节接装纸包角使接装纸涂胶量保持稳定,进而使接装纸透气度及滤嘴通风率保持稳定。     

浅析猪舍通风设计与靶向通风介绍

文章分析了目前在猪场设计中常用的几种通风模式的优缺点，指出了猪舍通风需要解决的问题和方法。并提出了靶向通风系统在猪舍特别是楼房猪舍通风中的应用。提出靶向通风可以很好地解决目前楼房猪舍中存在的空气过滤和除臭两个问题。     

Predicting the effect of fresh gas flow on tidal volume in volume-controlled mechanically ventilated dogs

ObjectivesTo determine if the tidal volume (V_T) delivered (V_TDEL) to canine patients being mechanically ventilated by a volume-controlled ventilator differed from the volume set on the ventilator (V_TSET) at three fresh gas flow (FGF) rates. To determine if V_TDEL could be accurately predicted by an FGF-based mathematical model.Study designProspective proof-of-concept study.AnimalsA total of 23 adult client-owned dogs undergoing elective orthopedic surgery.MethodsDogs were anesthetized and ventilated with a volume-controlled mechanical ventilator with constant respiratory rate (f_R) of 10 breaths minute^–1, inspiratory-to-expiratory ratio of 1:2 [fraction of inspiratory time (T_I) in one respiratory cycle (T_tot) 1:3], and V_TSET as body weight (kg) × 15 (mL kg^–1). V_TDEL was measured in 20 dogs at three FGF (500, 1000 and 4000 mL minute^–1). A mathematical model was used to calculate predicted volume (V_TPRED) for each animal at each FGF: V_TSET + {FGF × [(T_I/T_tot)/f_R]}. Linear repeated measures models were fit comparing V_TDEL to V_TSET and to V_TPRED by FGF.ResultsV_TDEL was significantly higher than V_TSET at every FGF (p < 0.05), and differences were larger at higher FGF (p < 0.001). There were no statistically significant differences between V_TDEL and V_TPRED at FGF rates of 500 and 4000 mL minute^–1 and, although the mean V_TDEL was statistically significantly higher than V_TPRED at FGF 1000 mL minute^–1 (p = 0.017), the mean difference of 9 mL was not clinically significant.Conclusions and clinical relevanceDogs on volume-controlled ventilators may be ventilated at a higher V_TDEL than intended depending on the FGF settings. Ventilation of small animals at high FGF could inadvertently induce pulmonary damage. A mathematical equation can be used to achieve a desired V_TDEL by adjusting V_TSET values based on FGF, f_R and T_I/T_tot.     

激素、通气和pH值对四倍体刺槐和二乔刺槐离体生长的影响

以四倍体刺槐和二乔刺槐的不定芽为试验材料,通过比较培养前后的芽伸长量、增殖率和生物量等指标,研究了激素、通气状况(封口材料)、培养基pH值对刺槐离体生长的影响.结果表明,在BA0.5mg/L、NAA0.1mg/L时,四倍体刺槐不定芽的生物量最大;在BA0.5mg/L、NAA0.5mg/L时,二乔刺槐不定芽的生物量最大.在湿度为35%±5%环境条件下,四倍体刺槐封口材料以耐高温塑料最好,二乔刺槐以棉塞最好;在湿度为55%±5%条件下,四倍体刺槐和二乔刺槐均以棉塞最好.在pH值为5.6、5.8和6.0时四倍体刺槐的增殖系数大,二乔刺槐在pH为6.4时的增殖系数大,而两品种在不同pH下的质量增量百分率差异不显著.     

袋装玉米露天堆垛自然通风降水试验

利用吉林省春季风大，湿度低的条件，对水分１８％以下的袋装玉米进行露天堆垛自然通风降水试验，结果表明，自然通风储藏２个月，玉米水分从１５．９％～１７．８％分别降到１３．９％～１４．４％玉米发芽率没有明显变化，蛋白质，纤维素，粘度，淀粉，灰分，脂肪酸等与烘干，晾晒的玉米相比明显判别，该方法可作为解决中，小型粮库高水分粮的降水辅助措施。