地沟式污水土地处理和人工湿地中植物对磷去除的效果研究

采用盆栽实验和中试实验系统，研究了地沟式土地处理系统和人工湿地中不同植物对磷的去除效率。结果表明，7种试验植物对生活污水中的磷均有很高的净化率，其中以芋头、菖蒲和岩豆藤3种植物对磷的净化效率最高。同时还对中试各处理槽的不同位置和深度的土壤中的微生物种类和数量进行了分析，进一步阐述了地沟式土地处理系统和人工湿地中植物的除磷机理。     

谷物清选机构主要参数优化设计试验研究

在现有气流振动筛选谷物清选机构使用条件一定的情况下，选择影响清选工作质量的4个主要运动学参数，即振动频率、加速度大小和加速度方向角以及气流速度作为设计变量，通过回归正交设计和台架试验的方法建立了清选工作质量与4个设计变量之间的数学模型，并通过优化设计求出这4个设计变量的最优配合方案。     

谷子收获机风筛式清选装置试验分析

为了减少谷子联合收获的清选损失,对谷子收获机风筛式清选装置进行了试验分析。运用参数可调的风筛式谷子清选装置,以清选风速、风向、筛分振幅和曲柄转速为试验因素,以籽粒损失率和含杂率为试验指标,对谷子联合收获机脱出物进行了清选试验。试验结果表明:籽粒损失率随清选风速、筛分振幅、曲柄转速的增大而增大,随清选风向角度的增大呈先增大后减小再增大趋势;含杂率随清选风速、筛分振幅、曲柄转速的增大而减小,随清选风向角度的增大呈先减小后增大再减小趋势;最优清选工作参数为清选风速4.19 m/s、清选风向30.3°、筛分振幅22 mm和曲柄转速218 r/min,籽粒损失率为2.02 %,含杂率为8.01 %。该研究为谷子联合收获机清选装置结构与工作参数设计提供参考。      

油莎豆收获装备的设计研究

油莎豆属莎草科莎草属的一年生块茎草本植物,根系发达,收获难度大,直接收获易造成籽粒破碎,作业质量较难保证。本文研究设计一种油莎豆收获机,主要由机架、输送分离装置、脱粒分离装置、清选装置等部件组成,采用多重清选功能使该机具有良好的流动性和分离性,可实现油莎豆机械化收获过程中籽粒与杂质土、根茎的高效分离清选。本文以籽粒损失率和含杂率为评价指标,通过设置各部分不同转速,进行3因素3水平正交试验,最终确定油莎豆收获机的最佳参数组合,为各关键部件设计、改进及参数选择提供依据。     

微型小麦联合收获机旋风分离清选系统研究

利用自制清选系统试验台,选择影响清选性能指标的5个主要参数,分离筒上锥角、筒体高度、导向片数量、吸杂风机转速和扬谷器转速作为设计变量,通过正交试验、二次通用旋转组合试验和优化设计,得出了各参数的最优组合,为微型小麦联合收获机清选系统的设计提供了依据。     

基于流固耦合的绿豆清选装置数值模拟分析

针对绿豆收获清选过程中清选损失率高、籽粒含杂率高的问题,研发了一种双斜面风筛式绿豆清选装置。运用流固耦合仿真模拟绿豆清选过程,并开展了正交试验。同时运用二次回归方程分析和响应面分析等方法对相关试验因素对籽粒含杂率、清选损失率的影响进行了探究。进行了最优组合参数验证试验,试验结果表明,该参数组合符合性能指标要求,实物模型可用于后期田间试验。     

间作模式下小麦联合收获机清选装置CFD-DEM气固耦合仿真与试验验证

为了提高间作模式下小麦联合收获机清选性能,研究旋风分离筒内流场和颗粒的运动状态,探索分离筒的最佳工作参数组合,运用离散元法和计算流体力学耦合的方法分析了气流与颗粒的相互作用,以喂入速度、吸杂压强、筒体高度、下椎体角度为试验因素对清选过程进行了仿真正交试验,对最佳清选参数组合完成了田间试验验证。结果表明:气流在分离筒内形成内、外旋涡,内漩涡的运动使短茎秆进入吸杂管道,籽粒在外旋涡的作用下滑落到集粮盘;仿真试验的最佳参数组合为喂入速度12 m·s^-1吸杂压强-1 800 Pa、筒体高度350 mm、下椎体的角度65°,得到的清洁率和损失率分别为92.18%和1.99%,与田间试验的误差分别为2.947%和7.428%。     

An investigation into the bacterial contamination of goniolenses in use in clinical practice

Objectives To report the incidence and evaluate the clinical significance of goniolens bacterial contamination in clinical use in dogs with three different usage protocols and one with an added cleaning protocol. Animals Studied and Methods Three groups of twenty dogs undergoing gonioscopy at a private practice in the UK had the goniolenses swabbed for bacteriology culture and identification prior to placement on the cornea. Three protocols of lens use, with 2 different types of goniolens, were studied. One protocol was then repeated with 21 dogs with a lens cleaning protocol prior to storage. Results Low levels of bacterial contamination were found in all 3 initial groups (10‐15%). No correlation was found between usage protocol used and rate of contamination and no correlation was found between length of storage between use and contamination. All bacteria cultured were considered naturally occurring commensals for the canine eye and environment. The group with a cleaning protocol had a 4.7% contamination rate. This was not statistically different from the non‐cleaning groups. Conclusions The rate of bacterial contamination of goniolenses in clinical practice is low and the bacterial contaminants consist of commensal bacteria, unlikely to be of detriment to the eye. Minimal contamination of the goniolenses was found and this did not appear to be of clinical significance. The introduction of a simple cleaning protocol did not produce a statistically significant reduction in bacterial contamination.     

Prescribed burning and hexazinone herbicide as release treatments in a sapling hardwood-loblolly pine stand

To compare release treatments, a randomized complete block study was established in a 7-year-old hardwood-loblolly pine (Pinus taeda L.) stand in central Louisiana established using chopping and burning. There were 5 blocks of 3 treatments each: (1) check, (2) hexazinone applied once, and (3) prescribed backfiring applied twice. The first burn in December 1985 (7 years after site preparation) had a fire intensity of 90 kJ/s/m. The hexazinone herbicide was applied in April 1986 (the 8th year after site preparation) with a metered spotgun applicator at a rate of 3.0 kg active ingredient/ha. The second burn in March 1989 (the 11th year after site preparation) had a fire intensity of 106 kJ/s/m.The two prescribed burns increased the number of stems less than 1.5 m tall from 1,380 to 2,960/ha red maple (Acer rubrum L.), blackgum (Nyssa sylvatica var. bifora), and sweetgum (Liquidambar styraciflua L.). Burning reduced the number of loblolly pines less than 2.0 m tall, which resulted in a significant increase in average loblolly pine height and diameter. Loblolly pine comprised 62 and 59% of the basal area on the check and burn treatments, respectively, 11 years after site preparation. Hexazinone reduced the number of blackgum, sweetgum, and oak (Quercus spp.) from 6,100 to 4,560 stems/ha and resulted in significantly less hardwood tree basal area than found on the check or burn treatments. Therefore, the herbicide treatment resulted in principally a loblolly pine stand (over 80% of the total tree basal area was pine) four years after hexazinone application.