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This paper describes the practical use of a global positioning system receiver (hand-held GPS) as a means of measuring and describing pasture areas invaded by weeds. The accuracy of two GPS units, a hand-held GPS with an external antenna (GPS with an antenna) and the differential global positioning system receiver (DGPS), were examined in Morioka, northern Japan. In addition, an area of weed patches and a pasture, determined using the GPS with an antenna, were compared to the measurements made with a conventional tape and a weed map was created based on the coordinate data of latitude and longitude measurements. The accuracy of the GPS with an antenna was poor (8.3 m); however, the precision of the unit was reasonable in measuring area. An area estimation error by the GPS with an antenna was 7% when practically measuring weed patches of 141 m2 and 1% in a paddock of 12 566 m2 . From these results, it appears that the GPS with an antenna might have an acceptable error in measuring areas for weed control in a pasture. A weed map produced from the coordinate data surveyed using the GPS with an antenna enables the state of weed growth and its domination in an area of pasture to be visually understood. Therefore, GPS technologies easily can be applied to quickly obtain information on weed infestation. 相似文献
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Thoroughbred racehorses perform exercise at maximal intensities and typically display a hyperthermic exercise response, which can drive core body temperature to critical levels. Despite extremely efficient thermoregulatory mechanisms, certain weather conditions may affect the horse’s ability to cool and result in a syndrome referred to as exertional heat illness (EHI). This is characterised by central nervous system dysfunction, as well as cytotoxic effects of heat on cells, which can produce deleterious consequences. Early detection of exertional heat illness (EHI) in Thoroughbred racehorses can be difficult because signs are often vague and the measurement of rectal temperature as an indicator of hyperthermia is not practical. Best practice in the treatment of EHI in horses, as in human subjects, centres on early detection, rapid assessment and aggressive cooling. Research in human subjects has shown that EHI is manageable when recognised early and appropriate treatment provided. The aim of this study was to investigate the measurement of skin surface temperature (SST) by an infrared thermometer as an aid in the early detection of EHI. A skin surface temperature ≥39°C in the immediate postrace period is considered to be hot. It reflects the interaction of exercise-related metabolic heat production, physiological adjustments to the skin surface such as vasodilation and sweating, together with the effect of high ambient temperature. Most importantly, high SST is associated with a reduced core-to-skin temperature difference, which retards heat transfer from the deep body tissues to the skin and can hinder heat dissipation. Identification of horses with high SSTs can prioritise them for rapid cooling and curtail possible progression to EHI. 相似文献
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烟草育苗期合理剪叶可实现促根壮苗,是烟叶高产稳产的重要环节。为了适应中小规模育苗的机械化需求,设计了一种锂电池装在手柄内的手持式剪叶机,由直流电机驱动无人机的碳纤维两叶螺旋桨作为剪叶机的刀片,高速旋转的桨叶产生急速气流,在完成切割叶片的同时实现了碎叶收集,且在45°风道出口装有碎叶收集网袋,残叶被桨叶产生的旋风吹向网袋暂存。试验结果表明:剪叶机结构简单,使用方便,具有较高的推广应用价值;掉渣率为2.59%,伤苗率为0.4%,漏剪率为1.09%,平均工作效率可达188.4m^2/h。 相似文献
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Nele Verhulst Bram Govaerts Victoria Nelissen Ken D. Sayre Jose Crossa Dirk Raes Jozef Deckers 《Field Crops Research》2011
Crop growth and development as well as yield are the result of the efficiency of the chosen agricultural management system within the boundaries of the agro-ecological environment. End-of-season yield results do not permit the evaluation of within-season management interactions with the production environment and do not allow for full understanding of the management practice applied. Crop growth and development were measured during the 2004, 2006 and 2008 crop cycles with an optical handheld NDVI sensor for all plots of the different management treatments of a long-term (since 1991) sustainability trial in the highlands of Mexico. Cropping systems varying in (1) tillage (conventional vs. zero tillage); (2) residue management (retention vs. removal); (3) rotation (monocropping vs. a maize [Zea mays L.]/wheat [Triticum aestivum L.] rotation) were compared. The NDVI-handheld sensor was evaluated as a tool to monitor crop growth and development and was found to be an excellent tool for this purpose. There was a strong relation between NDVI and biomass accumulation of maize and wheat. The measurement with the handheld sensor was non-destructive and fast so that a representative plot area could be measured easily and time-efficiently. Zero tillage induced different crop growth dynamics over time compared to conventional tillage. Zero tillage with residue retention is characterized by a slower initial crop growth, compensated for by an increased growth in the later stages, positively influencing final grain yield. Also crop rotation influenced early crop growth, with lower NDVI values for crops sown after wheat than crops after maize. Zero tillage with residue removal had low NDVI values throughout the growing season. Zero tillage with retention of crop residues results in time efficient use of resources, as opposed to conventional tillage, regardless of residue management, and zero tillage with residue removal. The results indicated that different tillage, rotation and residue management practices influence crop growth and development. It is important to monitor and understand crop growth under different management systems to select the right varieties and adjust timing and practice of input supply (fertilizer, irrigation etc.) in a holistic way in each cropping system. 相似文献
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基于可见/近红外局部透射光谱,根据马铃薯大小及形状特征,设计了便携式马铃薯多品质无损检测装置,包括光谱采集模块、光源模块、控制与显示模块、供电模块和黑白参考盒,装置尺寸为11 cm×6.5 cm×9.5 cm。选取大西洋品种马铃薯样品85个,基于装置建立了马铃薯含水率、淀粉质量分数和还原糖质量分数的偏最小二乘定量预测模型,马铃薯含水率、淀粉质量分数和还原糖质量分数预测模型验证集相关系数分别为0.927 8、0.914 6、0.933 8,均方根误差分别为0.325 3%、0.344 9%、0.041 6%。基于QT开发工具,采用C/C++语言编写了装置实时分析控制软件,将所建预测模型植入到软件中,实现了马铃薯多品质参数实时无损检测一键式操作。最后对便携式马铃薯多品质无损检测装置的检测精度进行了验证。20个马铃薯样品含水率、淀粉质量分数和还原糖质量分数的装置预测值与标准理化值的相关系数分别为0.914 1、0.912 2和0.914 0,均方根误差分别为0.352 7%、0.340 4%和0.040 0%,平均偏差分别为0.295 1%、0.253 6%和0.031 6%,重复采样最大变异系数分别为0.006 7、0.012 4和0.123 1。结果表明:马铃薯多品质局部透射无损检测装置可以实现马铃薯含水率、淀粉质量分数和还原糖质量分数的实时无损检测。 相似文献
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手扶插秧机手传振动评价及振动传递特性试验 总被引：1，自引：1，他引：0
以某手扶插秧机手柄和接振人员手臂为研究对象,采用基于振动总值的日振动暴露量的评价方法对手扶插秧机在2种不同工况下的手传振动进行了复合试验评价,计算结果显示,该手扶插秧机日振动暴露量为2.442 m/s~2,满足欧盟指令规定的要求。对人体手臂进行了振动响应分析和振动传递特性分析,结果表明,在2种工况下手扶插秧机手柄处的振动传递到手臂上时,振动呈逐渐衰减的趋势;操作手扶插秧机时,手腕对振动能量的吸收最多;手部对8～16 Hz和100 Hz附近的振动能量吸收较差,考虑到100 Hz左右的中频振动是造成雷诺氏症的主要原因,因此,100 Hz左右的中频振动应为今后插秧机扶手振动研究控制的重点。 相似文献
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我国虽是马铃薯的种植和产量大国,但马铃薯种植的机械化水平不高,特别西南山地马铃薯的种植仍以人力、畜力方式进行。这种种植方式劳动强度大,生产效率低,还会造成株距和行距不一致、播种深度不均匀,严重影响马铃薯的产量;同时,大部分以拖拉机为动力的马铃薯播种机因受地形限制又不适于应用。为此,拟研制一种集开沟、播种、施肥和覆土于一体的小型手扶式马铃薯播种机,以部分克服西南山地马铃薯种植作业中目前存在的不足,为该地区马铃薯种植业实现部分机械化作业提供一种新参考和为同类小型农业机械设备的研制提供技术借鉴。 相似文献