An approach for draft prediction of combination tillage implements in sandy clay loam soil

A methodology to predict the draft requirements of combination tillage implements in any soil and operating conditions was developed. This methodology required the draft requirements of individual tillage implements in undisturbed soil condition and draft utilization ratio of the rear passive set of combination tillage implement, which is defined as the ratio of the drafts of the rear passive set operating in combination and individually. Laboratory experiments were conducted to measure the draft requirements of a reference tillage tool (single disk), three scale-model individual (moldboard plow, cultivator and disk gang) and two combination (moldboard plow with disk gang and cultivator with disk gang) tillage implements at different depths (5, 7.5 and 10 cm), speeds (1.2, 2.2, 3.2 and 4.2 km/h), wet bulk densities (in the range of 1.27–1.85 g/cm³) and cone index penetration resistance values (in the range of 445–1450 kPa) in soil bin filled with sandy clay loam soil. The average draft utilization ratio of the reference tillage tool obtained were analyzed by both orthogonal and multiple regression techniques to develop the regression equation considering soil properties, operating and tool parameters. The developed draft equation based on the above mentioned methodology was verified with the data obtained for the draft of scale-model and prototype combination tillage implements in the laboratory and field conditions, respectively. It was found that the developed equation predicted the draft of both combination tillage implements within an average absolute variation of 18.0 and 13.5%, respectively.     

Investigation of inter fiber cohesion in yarns. I. Influence of certain spinning parameters on the cohesion in cotton yarns

This paper investigates the influence of raw material and process parameters in spinning that affect the inter fiber cohesion in yarns. An instrument has been developed for measuring the minimum twist of cohesion. With regard to the raw material parameters, the influence of different cotton fiber mixings for a given count of yarn is investigated. Also the effect of spinning to varying counts for a given cotton variety is studied. With regard to the process parameters, studies have been carried out to investigate the influence of noil extraction in comber, number of draw frame passages, draft pressure in ring frame and direction of twist. Cohesion improved with increase in the noil extraction percentage in the comber. Increase in the number of draw frame passages also improved the cohesion. Draft pressure in ring frame improved the fiber cohesion in yarn up to a pressure of 2.1 kg/cm². Direction of twist had no effect on the cohesion.     

论牛的肉用、役用经济类型划分的意义和方法(BPI指数)

关于以一个量值指标来划分现今典型的肉用型牛和役用型牛品种，还未见有报导，本文提出肉用指数（Beef purpose index，简写BPI），即平均成年活重与体高的比值，作为划分肉用牛与役用牛（品种）的量值指标，经对国内外74个肉牛和役牛品种（类型）资料计算，平均BPI值，公牛：4．56kg/cm，母牛3．32kg/cm，以此作为划分役牛，肉牛的基本界限，与传统抽象描述法划分结果吻合良好，符合比率由92．6％，（国外肉用品种公牛平均值）到97．9％（国内黄牛品种母牛平均值）。     

Design and performance of an adjustable three-point hitch dynamometer

Mounted implements necessitate the use of a three-point hitch dynamometer to measure the forces between the tractor and implements. In this work, an adjustable three-point hitch dynamometer was designed to fit most of the implements (standard and non-standard) available in Jordan. The dynamometer consists of three telescoping beams connected to a central T-shaped box. The system provides variable width and height of the dynamometer to satisfy a wide range of implement dimensions. Strain gages attached to cantilever beams were connected to a Wheatstone bridge in such a manner that only draft force is measured. The dynamometer was calibrated and several field tests were conducted to measure the force required to pull a chisel plow in a Jordanian clay loam soil at various depths and speeds. Different sets of strain gages can be attached and arranged in the bridge so that only the lateral or vertical forces can be measured.     

非光滑表面对推土板的土壤粘附与阻力的影响

土壤对机械和机具的粘附是一个亟待解决的重要问题。本研究根据典型土壤动物蜣螂头部非光滑表面形貌设计了非光滑推土板。这种非光滑推土板的推土阻力随着推土板表面贴敷的小凸包的分布、凸包材料、切削速度、切削角、切削深度及土壤含水量的不同而变化。含水量由30.38％增加到35.50％,推土阻力随之减小。精选推土板之平均最大降阻可达30％。研究结果还表明超高分子量聚乙烯(UHMW—PF)能够明显地减粘降阻。     

违约方合同解除规则探讨——基于《民法典合同编(草案)》视角

《合同法》对违约方解除规则付诸阙如,《合同法》第94条、第110条并非违约方解除的请求权基础。将违约方解除规则纳入《民法典合同编》有其正当性、必要性和可行性,但是,应当严格限缩违约方解除的触发条件。违约方解除规则并非赋予违约方以解除权,而是赋予司法机关以裁判依据,宜将违约方解除的行使方式限定为裁判解除而排除通知解除的适用,并且对违约方施以催告义务。     

Benefits of site-specific subsoiling for cotton production in Coastal Plain soils

The negative impacts of soil compaction on crop yields can often be alleviated by subsoiling. However, this subsoiling operation is often conducted at unnecessarily deep depths wasting energy and excessively disturbing surface residue necessary for erosion control and improved soil quality. A corn (Zea mays L.)–cotton (Gossypium hirsutum L.) rotation experiment was conducted over 4 years on a Coastal Plain soil with a hardpan in east-central Alabama to evaluate the potential for site-specific subsoiling (tilling just deep enough to eliminate the hardpan layer) to improve crop yields while conserving energy. Seed cotton yield showed benefits of subsoiling (2342 kg/ha) compared to the no-subsoiling treatment (2059 kg/ha). Averaging over all years of the study, site-specific subsoiling produced cotton yields (2274 kg/ha) statistically equivalent to uniform deep subsoiling at a 45 cm depth (2410 kg/ha) while not excessively disturbing surface soil and residues. Significant reductions in draft force were found for site-specific subsoiling (59% and 35%) as compared to uniform deep subsoiling at a 45 cm depth in shallow depth hardpan plots (25 cm) and medium depth hardpan plots (35 cm), respectively. Calculated fuel use for site-specific subsoiling was found to be reduced by 43% and 27% in the shallow and medium depth hardpan plots, respectively, as compared to uniform deep subsoiling in these same plots. Producers in the Coastal Plains who can determine (or who know) the depth of their root-impeding layer and perform site-specific subsoiling can have comparable cotton yields to traditional uniform depth subsoiling with reduced energy requirements.     

Effect of soil characteristics, seeding depth, operating speed, and opener design on draft force during direct seeding

Direct seeding practices that promote soil and water conservation and reduce input costs have become an increasingly accepted alternative to conventional tillage systems in western Canada. The objective of the present study was to determine the relative importance of soil characteristics, seeding depth, operating speed, and opener design on draft forces during direct seeding in central Saskatchewan. Draft was measured for nine different openers operated at 1–5 cm seeding depths and three ground speeds in four untilled Chernozemic soils that differed in soil moisture and/or texture. The average increase in opener draft for all fields was 4% for each km h⁻¹ increase in speed. Although the range in soil consistency was small, there was a 24% increase in draft in heavy clay compared to sandy loam soil. Draft force of the average opener increased by nearly 20% for each centimeter increase in seeding depth. However, highly significant interactions among most of the variables investigated indicated that the relative performance of openers was not consistent for the range of conditions evaluated. Large differences among the draft forces of different openers operated at different depths in soils with different consistencies were particulary noteworthy. For example, a 4.5-fold increase in the draft of a low versus a high draft opener operated at 1.25 versus 5.0 cm seeding depth at 7.5 km h⁻¹ in moist, heavy clay soil emphasized the large influence that opener design and seeding depth have on tractor power requirements and direct seeding input costs.     

不同砧木对嫁接西瓜性状的影响

嫁接西瓜采用不同砧木对嫁接苗成活率，营养生长，产量抗病性等性状具有不同的效果，江汉地区以瓠瓜砧木最佳。     

Real-time estimation and irregularity control of the sliver draft system

High regularity is important in manufacturing spun yarn. Among controllers used in regularity control, existing PID controller is suitable for linear time-invariant systems but not for the control of sliver draft systems with non-linear characteristic. Thus, the present study designed a knowledge-based fuzzy controller in consideration of disturbance and non-linear characteristic of sliver draft systems. RLS (Recursive Least Squares) was used as an estimation algorithm to formulate a model used in computer simulation for implementing the controller, and real time estimation was made using real data from draft systems to get a model close to actual systems. This research used a estimation model in designing a knowledge-based controller that minimizes the variation of control response to the sliver linear density of the system, and the result of linear density control was used to prove the superiority of the controller in control performance through CV%.