Splitting Severity Among Rabbiteye (Vaccinium ashei Reade) Blueberry Cultivars in Mississippi and Louisiana

Abstract

A survey of blueberry growers determined the extent of rain-related splitting fruit on blueberry production in Mississippi and Louisiana. Growers were asked to approximate (1) the number of acres or plants of each cultivar on their farm (2) the severity rating (1 = No splitting-5 = Severe splitting) of each cultivar, and (3) the percent of berries lost to rain-related splitting. Among the 3 most widely planted cultivars, ‘Premier’ exhibited the least splitting (1.2 rating) followed by ‘Climax’ (2.2) and ‘Tifblue’ (3.1) had the most split fruit.     

香蕉茎杆纤维提取加工设备的结构改进

通过改进切割破片机的关键部件切割刀具结构和采用不切割茎杆芯部的工艺方案等,使设备功耗和切割阻力大大减少,解决了茎杆撕裂、折断和腐烂茎杆加工问题,大大提高了适应性;通过增加排渣槽上方侧板、刀轮罩内表面横板,增大刀轮罩与刀轮的间隙和增设刀轮罩两端消声孔等改进设计,使刮麻机喂料口风速降低约90.8%,空载噪声降低约6 dB(A),大大减少了茎杆渣飞溅现象,改善了喂料和工作条件,提高了加工效率。     

2BP-2000型水稻育秧播种机分盘装置研制

针对现有育秧播种机分盘装置生产效率较低、高速作业时易出现卡盘和秧盘输送不连续等问题,该研究设计了一种生产效率不低于2 000盘/h的机械气动式自动分盘装置,可快速、准确完成分盘和供盘,适配2BP-2000型水稻育秧播种机高速播种。阐述了分盘装置的基本结构和工作原理,开展分盘、接盘过程分析,确定装置稳定分盘、接盘作业的关键机构与工作参数。分盘稳定性试验结果表明,生产率为1 600～2 000盘/h时,分盘稳定性不低于98.67%。开展以层叠秧盘数、生产率和秧盘质量为试验因素,以接盘成功率为试验指标的三因素三水平正交旋转组合试验,得到影响接盘成功率的因素主次关系为生产率、层叠秧盘数、秧盘质量,其中生产率、层叠秧盘数对接盘成功率影响显著（P <0.05）,秧盘质量对接盘成功率影响不显著（P≥0.05）,表明分盘装置对不同质量的秧盘适应性较好,其最优参数组合为：生产率2 000盘/h、层叠秧盘数6盘/层、秧盘质量750 g/盘,该条件下分盘装置的接盘成功率均值为98.43%,与预测值仅相差0.29个百分点。研究结果对提高水稻硬盘育秧播种机械化水平具有实用价值。     

Late nitrogen application increased protein concentration but not baking quality of wheat

Late application of nitrogen (N) fertilizers at heading or anthesis is usually performed to produce wheat (Triticum aestivum L.) with high bread‐making quality. However, increasing energy costs and ecological problems due to N losses call for efficient and simplified N fertilization strategies. This study aimed to investigate the effect of late N fertilization on grain protein quality and thus baking quality and to evaluate if similar wheat quality can be maintained without late N application. Field experiments with two winter wheat cultivars differing in quality groups were conducted. The fertilization treatments comprised a rate of 220 kg N ha^?1 applied in two or three doses (referred to as split N application), and 260 kg N ha^?1 applied in four doses (additional late N fertilization) with different N fertilizer types. The results show that although split N application had no effect on grain protein concentration (GPC), it affected N partitioning in the grain, increasing mainly the concentration and proportion of the glutenin fraction. As a result, baking quality was improved by split N application. Late N fertilization enhanced GPC and the relative abundance of certain high molecular weight glutenin subunits (HMW‐GS). However, it had no effect on N partitioning in the grain and did not further improve baking quality. No obvious differences were found between N fertilizer types on grain yield and quality. The N fertilization effect was more pronounced on the wheat cultivar whose baking quality was more dependent on protein concentration. In evaluating baking quality of wheat flour, gliadin and glutenin proportions were better correlated with loaf volume than the overall protein concentration.     

Analytical models for splitting capacity of bottom rails in partially anchored timber frame shear walls based on fracture mechanics

Plastic design methods can be used for determining the load-carrying capacity of partially anchored shear walls. For such walls, the leading stud is not fully anchored against uplift and tying down forces are developed in the sheathing-to-framing joints and the bottom rail will be subjected to crosswise bending, leading to possible splitting failure of the rail. In order to use these plastic design methods, a ductile behaviour of the sheathing-to-framing joints must be ensured. In two earlier experimental programmes, the splitting failure capacity of the bottom rail has been studied. Two brittle failure modes occurred during testing: (1) a crack opening from the bottom surface of the bottom rail and (2) a crack opening from the side surface of the bottom rail. In this article, a fracture mechanics approach for the two failure modes is used to evaluate the experimental results. The comparison shows a good agreement between the experimental and analytical results. The failure mode is largely dependent on the distance between the edge of the washer and the loaded edge of the bottom rail. The fracture mechanics models seem to capture the essential behaviour of the splitting modes and to include the decisive parameters.     

基于流固耦合的淹没水射流柑橘分瓣研究

针对国内柑橘分瓣过程中存在的劳动力成本高、分瓣效率低下等问题,通过对柑橘模型进行流固耦合的淹没水射流仿真研究,验证了水分离在柑橘分瓣中的可行性。首先基于Ansys Workbench平台对柑橘结构和喷嘴内外部流场响应进行单向流固耦合联合求解;其次对柑橘在流固耦合作用下的应力分布进行了分析;最后采用不同喷距对柑橘模型进行仿真试验,并通过建立试验平台加以验证。结果表明,当喷距为50 mm时,在水射流的冲击作用下,柑橘内部存在剪切破坏,受到的最大剪切应力最大,形成剪切裂纹,裂纹进一步扩展使得柑橘分瓣。     

Investigation on the Stabilization of Flame and Control of Fuel-oil Splitting Decomposition Spray by Anti-flow

On the basis of trial and theory, this paper advances an effective preventive measure to solve the problem of producing black smoke during fuel oil thermolysis and polluting the atmosphere in the process of combustion. It provides valuable references to protect the environment,save energy and solve the problem of clean combustion of high-hydrocarbon fuel, especially fuel oils such as kerosene, diesel oil, heavy oil etc.     

土霉素处理对Valencia夏橙中淀粉及相关基因表达的影响

黄龙病(Huanglongbing,HLB)会造成柑橘韧皮部坏死堵塞,导致光合同化物运输不畅,淀粉大量积累。在感染HLB的4年生Valencia夏橙病株上分别注入0.1和0.2 g·株~(-1)土霉素(Oxytetracycline,OTC),90 d后运用qPCR检测,病株中HLB病原菌(Candidatus Liberibacter asiaticus,Las)含量均明显降低,且0.2和0.1 g·株~(-1) OTC处理的效果相当。I2/KI显色及LM观测表明,0.2 g·株~(-1) OTC处理后植株的淀粉含量从注射前的18.58μg·mm~(-2)减少至90 d的5.24μg·mm~(-2),而0.1 g·株~(-1)的处理90 d仅降至11.88μg·mm~(-2)。高效液相色谱(HPLC)检测结果表明,注射后90 d内,试验用浓度0.2 g·株~(-1) OTC在植株体内可降解至200μg·kg~(-1)以下。基因表达结果表明,注射0.2 g·株~(-1) OTC后30和90 d,淀粉合成及分解相关基因表达量均下降,其中淀粉合成相关基因AGPase表达量下降最显著,这与OTC注射后30和90 d叶片内淀粉含量下降结果一致。     

Experimental Study of Ratio Between Splitting Tensile Strength and Compressive Strength for PVA Fiber Cementitious Composites

An experimental study of the splitting tensile strength and compressive strength were carried out. Effects of PVA fiber was analyzed on ratio between splitting tensile strength and compressive strength. The dimensions of cubic specimens were 100 mm×100 mm ×100 mm. PVA fiber were added at the volume fractions of 0, 0.5%, 1%, 1.5%, 2% and the fly ash content were 30%, 50%. The test results indicate that, the compressive strength varies very little after incorporation with PVA fiber, however, the splitting tensile strength increases from 42.64% to 135.12% and the ratio between splitting tensile strength and compressive strength increases from 36.82% to 134.27%. What's more, the compressive strength of cementitious composite including fly ash at the ratio of 30% is 20% higher than that of 50%,and there is no obvious improvement on the splitting tensile strength with the change of fly ash content. This paper also shows that the compressive test cube of PVA fiber cementitious composites has multiple cracks and is hardly crumbled in the degradation process, and then the compressive toughness can be enhanced significantly.