The galvanic dissolved oxygen sensor finds widespread applications in multiple critical fields due to its high precision and excellent stability. As its core sensing components, the oxygen-permeable membrane, electrode, and electrolyte significantly impact the sensor’s performance. To systematically investigate the comprehensive effects of these core sensing components on the performance of galvanic dissolved oxygen sensors, this study selected six types of oxygen-permeable membranes made from two materials (Perfluoroalkoxy Polymer (PFA) and Fluorinated Ethylene Propylene Copolymer (FEP)) with three thicknesses (0.015 mm, 0.03 mm, and 0.05 mm). Additionally, five concentrations of KCl electrolyte were configured, and four different proportions of lead–tin alloy electrodes were chosen. Single-factor and crossover experiments were conducted using the OxyGuard dissolved oxygen sensor as the experimental platform. The experimental results indicate that under the same membrane thickness conditions, PFA membranes provide a higher output voltage compared to FEP membranes. Moreover, the oxygen permeability of FEP membranes is more significantly affected by temperature. Furthermore, the oxygen permeability of the membrane is inversely proportional to its thickness; the thinner the membrane, the better the oxygen permeability, resulting in a corresponding increase in sensor output voltage. When the membrane thickness is reduced from 0.05 mm to 0.015 mm, the sensor output voltage for PFA and FEP membranes increases by 86% and 74.91%, respectively. However, this study also observed that excessively thin membranes might compromise measurement accuracy. In a saturated, dissolved oxygen environment, the sensor output voltage corresponding to the six oxygen-permeable membranes used in the experiment exhibits a highly linear inverse relationship with temperature (correlation coefficient ≥ 98%). Meanwhile, the lead–tin ratio of the electrode and electrolyte concentration have a relatively minor impact on the sensor output voltage, demonstrating good stability at different temperatures (coefficient of variation ≤ 0.78%). In terms of response time, it is directly proportional to the thickness of the oxygen-permeable membrane, especially for PFA membranes. When the thickness increases from 0.015 mm to 0.05 mm, the response time extends by up to 2033.33%. In contrast, the electrode material and electrolyte concentration have a less significant effect on response time. To further validate the practical value of the experimental results, the best-performing combination of core sensing components from the experiments was selected to construct a new dissolved oxygen sensor. A performance comparison test was conducted between this new sensor and the OxyGuard dissolved oxygen sensor. The results showed that both sensors had the same response time (49 s). However, in an anaerobic environment, the OxyGuard sensor demonstrated slightly higher accuracy by 2.44%. This study not only provides a deep analysis of the combined effects of oxygen-permeable membranes, electrodes, and electrolytes on the performance of galvanic dissolved oxygen sensors but also offers scientific evidence and practical guidance for optimizing sensor design.

针对目前鱼塘投饲机定点投饲作业时,鱼群集中摄食而导致投饲区溶解氧不足,影响饵料利用率的问题,结合投饲区溶解氧稳定性特征规律研究提出投饲机优化设计思路.以振动式(VFM)、气动式(PFM)和风送投饲增氧一体式(AFM)3种投饲机为研究对象,基于鱼类呼吸耗氧模型及溶解氧收支平衡方程理论推导构建溶解氧稳定性模型,以溶解氧变异系数(DCV)为评价指标,深入分析投饲机作业时投饲区溶解氧变化规律.3种投饲机作业时DCV实测值和理论值分别为 43.56％、42.28％(VFM);12.50％、14.92％(PFM);1.96％、3.88％(AFM),验证了所构建溶解氧稳定性模型有效性,同时结果表明投饲机作业性能对溶解氧稳定性具有重要影响.基于试验结果提出溶解氧参数应作为投饲机优化设计的重要指标之一,并提出以提高投饲区溶解氧稳定性为目的,将溶解氧参数与机械参数相结合,从内部抛料结构、投饲模式(定点投饲改为动点投饲)及智能化水平(精准投饲增氧)3个方面进行投饲机优化改进的建议.

[目的]为了提高鹅种蛋孵化性能,针对现有鹅孵化机孵化过程自动化程度低、温度波动大、鲁棒性差,现场操作复杂等不足,设计了一种基于可编程逻辑控制器(Programmable logic controller,PLC)和云平台的鹅孵化机监控系统.[方法]根据鹅种蛋孵化工艺要求和鹅孵化机工作原理,采用PLC作为主控制器设计了系统的硬件电路和软件程序,实现孵化机温度、湿度、翻蛋和喷水晾蛋的自动控制,利用触摸屏和组态软件设计了孵化机现场监控的人机交互界面,并利用通用分组无线业务(General packet radio service,GPRS)智能网关、云平台服务器和移动端设计了远程监控系统.系统工作时,GPRS智能网关读取PLC中的存储数据,通过4G/5G网将数据上传至云平台服务器,移动端通过微信公众号、APP或网页可以直接访问和下载云平台服务器中的数据,并以图表形式显示出来.[结果]该监控系统运行稳定、状态良好;孵化过程中的温度采样数据鲁棒性高,100％达到控制要求;自动控制有助于提高鹅孵化机自动化水平;孵化生产试验结果表明,狮头鹅受精蛋平均孵化率为87.84％,比现有记载最高纪录高1.44％.[结论]该系统能够满足鹅种蛋孵化要求,且控制精度高,实现了鹅孵化机的自动控制、现场监控和远程监控,具有良好的人机交互界面,对促进农业装备自动化和信息化发展具有指导意义.

针对现代篱架型葡萄冠层面临农药"穿不透、用量大、飘移多"等瓶颈问题,提出一种新型隧道对流式风送施药方法,开发了一种具有高穿透性、低飘移的机械化施药装备.该装备的风送装置采用中心对称方式,风机为横流式,基于同向平行流自由射流理论设计风机出口宽度为138 mm,风道主体满足对数螺旋轮廓.叶轮的外径为157 mm,由23片厚度为1 mm的强前向弯曲叶栅固定成桶状结构,叶栅中心角为108°,内外径比为0.81.通过叶轮与风道引导气流循环往复在冠内多维流动,形成对葡萄树的隧道对流式风送.由MATLAB插值拟合,得到了门罩内空气对流循环的气流运动轨迹;速度场分布测试同样表明:有冠层情况下,冠内存在两侧风速高、中间均匀的隧道对流式循环气流.在隧道对流风送施药影响下,喷雾沉积垂直分布均匀性得到明显改善,喷射渗透增强,穿透性有效提高,雾滴的地面飘失与空中飘移量减少显著.该研究的试验结果为机具进一步优化改进提供帮助,同时新型隧道对流式风送施药技术或许是满足未来喷雾应用、环境的一种较有利的选择.

以高粱秸秆为原料,分别研究酸、碱、氧化试剂与低温冻融联合预处理对高粱秸秆与沼泥混合厌氧发酵产甲烷的影响.试验结果表明:经过预处理后各试验组高粱秸秆组分含量比CK对照组均有显著变化(p<0.05),木质素去除率在29.85％～41.71％之间,纤维素相对含量提高率在10.08％～17.27％之间,半纤维素去除率在1.30％～9.62％之间.预处理可有效改变高粱秸秆宏观和微观结构,改变高粱秸秆的组织结构特性,纤维素、半纤维素与木质素的连接被打断,木质素被脱除.各试验组累积甲烷产量比CK对照组显著提高30.69％～90.28％,经5％冰乙酸和低温冻融联合预处理后的试验组在试验周期内有最大累积甲烷产量351.85 mL/(g·VS).Logistic增长曲线方程对于高粱秸秆与沼泥混合厌氧发酵产甲烷规律具有较好的拟合效果,可对累积甲烷产量做出合理解释和准确预测,经济性和能量分析可为规模化生产提供参考.

鱼菜共生系统实现了水产和蔬菜间的物质循环转化,是一种零排放可持续的先进农业生产模式,为探究鱼菜共生系统中不同种类蔬菜生长状况及其对养殖尾水氮素转化的影响,设计了5种不同种类蔬菜(圣女果、线椒、蕹菜、芹菜、紫背菜)基于耦合型鱼菜共生系统的栽植试验.结果表明:在26 d的栽植试验中,各试验组蔬菜鲜质量和株高均有正向增长,根质量占比与鲜质量增长量关系的拟合曲线为一元二次方程,当根质量占比在34％～42％间时,植株各器官发育较好,对营养物质转化效率高,圣女果有最大鲜质量增长量28.43 g、最大株高增长量31.84 cm和最大株高相对增长率241.32％;试验中换水周期为3 d,各试验组水体氮化物浓度指标均显著下降,圣女果42 h氨氮相对去除率达69.17％,6 h内亚硝酸盐氮相对去除率为41.09％;在循环周期末期,水培组圣女果有最小氨氮质量浓度0.152 mg/L,pH值稳定在6.98左右,水培紫背菜有最大亚硝酸盐氮相对去除率55.25％和硝酸盐氮相对去除率42.35％.综上,在耦合型鱼菜共生系统中圣女果对养殖尾水的水质和氮素有较好的净化作用和转化效果.

Solar insecticidal lamps Internet of Things (SIL-IoT) is a new green prevention and control technology for pest management. In the implementation of SIL-IoT to large-scale regions, two practical issues remain to be solved, that is: 1) scheduling the cleaning tasks of SILs periodically and 2) minimizing the insecticidal efficiency reduction over time. As smartphones are widely available among farmers across the globe, mobile crowdsensing (MCS) for agricultural data collection becomes a cost-effective and efficient solution by integrating participatory sensing based on a large group of individuals. This article proposes an MCS-enabled framework to address the SIL maintenance problem (SILMP) and perform system analysis by considering both the partition structure of farmland and the insecticidal efficiency of SILs. In addition, considering the farmland's practical natural geographical features, we propose dividing the regions of interest into numerous subareas, where each subarea can be considered a separate partition. Finally, we formulate the SILMP framework as two subproblems, i.e., path planning and task selection, and propose two different methods to tackle each problem based on the concept of greedy algorithm. Simulation results show that our proposed methods have improved performance in the tradeoff between task cost and insecticidal efficiency and outperform the three selected baseline algorithms.

Highlights Lotus seed coats are often peeled using water jets, which has not been studied in-depth. A water jet-based lotus seed peeling system is proposed and investigated in detail. Response surface method experiment was used to enhance peeling-machine performance. Proposed system performs well in terms of cost, stability, and percentage of seed peeled and damaged. Abstract. Lotus seed coats are often peeled using water jets. However, currently, existing fresh lotus seed peeling machines could process lotus seeds only if their size differences are small. Due to a lack of research on water jet operation parameters, the peeling process is often associated with a low percentage of seed peeled (PSP) and a high percentage of seed damage (PSD). A new type of water jet-based fresh lotus seed peeling machine was designed and tested to solve the aforementioned problems. Three-factor, three-level response surface method (RSM) was used in experiments to enhance peeling-machine performance, and quadratic polynomial regression equations were obtained via analysis of the experimental data. Results show that these independent variables had significant effects on PSP and PSD: water jet pressure (X1), water jet angle (X2), and processing speed (X3). Specifically, X1 and X2 had an interactive effect on PSD, whereas X1 and X3 both had a strong interactive effect on PSP and PSD. The optimal parameters were a water jet pressure of 0.60 MPa, water jet angle of 20°, and processing speed of 62 rpm, leading to predicted PSP and PSD of 93.13% and 1.65%, respectively (similar to the validation experimental PSP and PSD of 93.89% and 1.76%, respectively); thus, proving the accuracy of the RSM model. In general, the proposed peeling machine provided a high machine capacity (19.65 kg/h), a high percentage of seed peeled, and a low percentage of seed damaged, and all performance indices fulfilled the requirements for use. Keywords: Lotus seed, Parameter optimization, Peeling, Water jet.

Abs tr a c t. Maximum head rice yield is related to the optimal harvest time or moisture content during rice maturity. The physi-cal properties of rice grains, such as the breaking forces, changed with the increasing degree of rice maturity. Harvest moisture con -tent, breaking forces for the dorsal and ventral sides of the brown rice kernel in a three-point bending test and the milling quality properties of rice at different maturity stages were investigated. The relationships between head rice yield and harvest moisture content and also between head rice yield and the breaking forces for the dorsal side and ventral side were analysed. The breaking forces for the dorsal side and ventral side increased at 30/37 and at 44/51 days after heading and decreased at 58/65 days after head-ing, the increasing and decreasing extent of the breaking force for the ventral side was larger than that for the dorsal side. The break-ing force for the ventral side was larger than that for the dorsal side during the maturity period. Head rice yield increased at 30/37 and at 44/51 days after heading, but head rice yield decreased at 58/65 days after heading. The breaking force for the ventral side increased by 9.52, 10.13, 8.59, and 7.33 N, head rice yield increased correspondingly 38.7, 30.7, 34.7 and 15.3% during maturity for different varieties. The moisture content at optimal harvest time with the maximum head rice yield and maximum breaking force for ventral side or dorsal side was 25-30%.

Given the impermeability, larger dosage, and higher drift of pesticides used in modern hedgerow vine canopies, a novel tunnel-convective air-assisted spraying technology was proposed. Mechanized spraying equipment with high penetration and low drift was developed. The air-assisted system of this equipment was centrosymmetric, and the fan type was cross-flow. The fan outlet width was 138 mm and the air duct‟s main body followed a logarithmic spiral profile, based on parallel flow theory. The external diameter of the impeller was 157 mm, which was fixed into a barrel structure by 23 strong forward-curved blades, each being 1 mm thick. The central angle of the blades was 108°, and the ratio of the internal and external diameters was 0.81. The impeller and air duct served as guides to circulate and reciprocate airflow around the crown, forming a tunnel-convective air-assisted to the vine. Using MATLAB interpolation, the airflow trajectory of the air convection circulation in the door-shaped cover was obtained. The velocity field distribution test showed that, in the case of a canopy, there were tunnel-convective circulating airflows with high velocity on both sides and uniform velocity in the middle of the canopy. Due to the tunnel-convective air-assisted spraying technology, the vertical distribution uniformity of spray deposition has been significantly improved, spray penetration has been enhanced, penetrability has been effectively improved, and droplets on the ground and in the air have been significantly reduced. The results of this study can assist in providing further optimization and improvement of plant protection machinery. The new tunnel-convective air-assisted spraying technology may be a more favorable choice for future spray applications and the environment.

以麦秸与鸡粪为原料,采用批次式中温厌氧发酵方式,探究微量元素Fe2+、Co2+、Ni2+对混合厌氧发酵的影响.实验结果表明:Fe2+、Co2+、Ni2+最佳浓度分别为210、32、32 mg/L,当Fe2+、Co2+、Ni2+的添加浓度在适宜范围内时,可显著(p<0.05)提高发酵系统产CH4潜力及CODs去除率;当Fe2+浓度为210 mg/L、Co2+浓度为32 mg/L、Ni2+浓度为32 mg/L时,其CH4累积产量分别为322.21、331.19、357.10 mL/(g VS),相比于对照组为245.35 mL/(g VS)显著(p<0.05)提高31.33％、34.99％、45.54％,CODs去除率依次为61.83％、57.01％、63.63％,提高CH4产量的排序为Ni2+>Co2+>Fe2+,Ni2+对CH4累积产量的提高最明显,同时也有最高的CODs去除率,且各实验组pH值均稳定在适宜范围内,厌氧发酵稳定运行,可为麦秸与家禽粪便的沼气工程提供技术参考.

针对茶园机械化开沟抛土性能不理想、无专用刀具的问题,设计了适用于茶园开沟的切抛组合式开沟刀.对抛土刀抛土片的抛土过程进行动力学分析,确定其关键参数抛土片宽度为8 cm、倾斜角为30°时,可保证抛土刀横向抛土幅宽满足农艺要求.性能试验表明:切抛组合式开沟刀单侧抛土幅宽为22.7 cm、抛土均匀性系数为90.3％、覆土厚度为2.1 cm、开沟深度稳定性系数为87.8％、沟底浮土厚度为1.2 cm,对照组单一开沟刀为13.4 cm、84.3％、2.4cm、82.3％、2.5cm,说明切抛组合式开沟刀更符合茶园开沟实际需求,抛土均匀性与开沟稳定性更好,所抛土壤不易落人沟内.功耗分析试验表明,与单一切土刀相比,切抛组合式开沟刀抛土的正后侧区域冲击力减小,抛土上方区域冲击力减小,从而导致其抛土总冲击力减小,因此,该组合式开沟刀提高了开沟抛土质量,同时未明显增大开沟功耗.

Highlights A measurement device for droplet mass deposit was improved to enhance its performance. A wireless data transmission system was used to achieve convenient data sharing. A user interface was designed for display and analysis of the measurement results. A positioning mechanism was designed for arranging measurement devices promptly. Abstract . Measurement of droplet mass deposit is important in spray research and spray performance evaluation. In this article, an online measurement device for droplet mass deposit was improved based on the original design. The measurement resolution, precision, and data stability were improved by optimization of the structure and components and by data filtering. The resolution reached 0.00067 mg cm-2. Comparison tests showed that the relative error between the original device and an analytical balance was 6.68% to 8.48%, and the relative error between the improved device and the analytical balance was 5.24% to 6.15%. Compared with the original device, the relative error decreased and the precision improved. The relative error between the improved device and a tracer method was 5.11% to 6.99%, and the precision of the improved device was close to that of the tracer method. A positioning mechanism was designed to arrange measurement devices promptly in the test area, and a wireless data transmission system was used to achieve convenient data sharing. A user interface was designed to display the results in the form of tables and contour maps. Tests were conducted to measure the droplet mass deposit distribution of one nozzle, the droplet mass deposit distribution in a tree canopy, and the uniformity of the droplet mass deposit distribution in a small horizontal area. The results showed that the improved measurement device could provide data promptly and conveniently for spray research and spray performance evaluation. Keywords: Device improvement, Mass distribution, Wireless communication.

[目的]针对Y型棚架式果树的需风特性设计一款风送喷雾机,探究机具对此树形的施药规律,为新式果园栽植工艺的植保机具设计提供参考.[方法]结合棚架梨树Y型树冠需风特性,设计一款异形导风管,确定发散型射流口,喷雾范围可全面覆盖冠层,并进行整机配置,风机使用无级调速带轮进行调速.以作业速度、出口风速、出风口与冠层中部高度差作为试验参数,以靶标雾滴覆盖率、靶标雾滴沉积量以及地面雾滴沉积量作为评价指标,设计田间试验.利用Design-Expert软件建立响应曲面分析参数对指标的影响,并对机具作业参数进行优化.[结果]优化结果表明:3WZ-300风送喷雾机在作业速度0.8?m/s、出口风速22?m/s、出风口中部与梨树冠层中部高度差为5.1?cm时,靶标雾滴覆盖率为39.79％,靶标雾滴沉积量为9.89?μL/cm2,地面雾滴沉积量为5.41μL/cm2,有效附着药液占比60.1％.[结论]该喷雾机满足果园作业要求,施药效果较好,为棚架式果园喷雾机的设计及机具参数优化提供了参考.

鲜莲子莲皮紧紧依附在莲仁表面,采用手工去皮成本高、效率低,难以满足生产需求.由于缺乏对水射流去皮机理及参数的研究,造成莲子去皮率低、损伤率高,为此设计一款基于水射流去皮的鲜莲子去皮机.将水射流压力、水射流倾角以及带轮直径作为影响去皮效果的因素,以去皮率、损伤率、带帽头率、开边率、掉莲率为评价指标,采用Design-Expert软件进行三因素三水平的响应曲面优化试验.结果表明:对去皮率、损伤率以及带帽头率的影响程度从大到小均依次为水射流压力、水射流倾角、带轮直径;对开边率的影响程度从大到小依次为水射流倾角、水射流压力,带轮直径对开边率的影响非常小;掉莲率都在1％左右,与3个影响因素无关.优化后最佳作业参数分别为:水射流压力0.7 MPa、水射流倾角18°、带轮直径68 mm,其指标预测值分别为:去皮率91.16％、损伤率0.96％、带帽头率2.40％、开边率0.04％.采用优化后的参数进行验证试验,得出去皮率为92.63％、损伤率为1.24％、带帽头率为2.72％、开边率为0.21％,各项指标的试验结果与理论预测结果的绝对误差均小于1.5％,验证了模型与所优化参数的合理性.

提出一种基于机器视觉的莲子去芯位置定位的方法,并搭建试验平台进行去芯验证.采集4个产地、不同尺寸的莲子,用2个相互垂直的摄像头采集凹槽内莲子图像,对图像进行裁剪和灰度处理后,通过莲子头部和尾部的灰度特征差异识别莲子朝向;对沿长轴尾部向上的莲子图像进行二值化处理,经腐蚀运算以消除边缘杂质,缩放以增大特征点的曲率,利用角点检测确定莲子去芯位置坐标后进行坐标换算,计算机械手移动距离,实现莲子去芯作业.试验表明:莲子理想去芯位置为莲子尾部凸点,莲子朝向判别成功率约97％,尾部凸点识别准确率约97％,整体识别成功率约94％,去芯成功率约93％,单颗莲子图像处理平均时间约78 ms,平均去芯时间约0.5 s.若以尾部凸点识别成功数为基数计算,则莲子去芯成功率可达98.9％.

为改善鹅种蛋孵化性能,以辐照度均匀度、孵化机容蛋量和安全性为指标,基于TracePro Expert光学仿真软件对孵化机内LED灯带布置进行仿真和安装设计,同时选用不同LED光照进行种蛋孵化试验,以确定最佳孵化期光照方案.结果 表明,在所设计的小型孵化机内,灯带条数为3条,水平间距为25 cm,安装高度距离蛋表面20 cm时为最佳布置方案,此时辐照度均匀度为0.692,满足建筑照明最低标准.与传统的黑暗条件孵化相比,辐照度为0.5～0.6 W/m2的LED红光和白光显著提高鹅种蛋孵化率,分别提高4.39和2.39个百分点,且缩短出雏窗口期约16h;而单色绿光能促进胚胎发育,利于鹅胚体重的增加.该研究结果可为后续高性能鹅种蛋孵化机的设计和优化提供参考.

In order to solve the problem of poor traveling stability and excessive pesticide application during plant protection operations in hilly orchards, a novel crawler-type multi-channel air-assisted sprayer that is particularly appropriate for hilly orchards was designed in this study. Considering anti-rolling requirements and the orchard environment in hilly areas, this study selected limits for uphill and downhill rolling angles as well as the transverse rolling angle as the evaluation indexes for determining both the layout and parameter settings of the sprayer. According to freely submerged jets and the requirements in plant protection operation, a multi-channel air-assisted system was developed. The test results showed that the anti-rolling performance and the designed air-assisted system were adequate. At 2 m from the longitudinal center plane of the sprayer, the airflow exhibited wavy distribution patterns under different parameter combinations since the four streams of the airflow were not thoroughly intersected and mixed. At 3 m from the longitudinal center plane of the sprayer, the jet was ejected at great velocity but underwent rapid attenuation; the airflow velocity in most areas barely satisfied the requirements for plant protection operation. In addition, different air outlet layout schemes led to significant differences in the spatial distribution of the airflow field. Compared with a traditional air-assisted sprayer, using the developed multi-channel air-assisted sprayer enhanced the droplet coverage uniformity by 19.4%, and the mean droplet deposition in the front, middle, and rear of the canopy was enhanced by 32.9%, 50.3%, and 78.1%, respectively, while reducing ground deposition and air drift by 26.8%. Keywords: fan, dual-flow-channel, plant protection, air-assisted, test DOI: 10.25165/j.ijabe.20201306.5362 Citation: Qiu W, Li X L, Li C C, Ding W M, Lv X L, Liu Y D. Design and test of a novel crawler-type multi-channel air-assisted orchard sprayer. Int J Agric & Biol Eng, 2020; 13(6): 60–67.

The current research investigated the effects of thermal-sonication pretreatment on the anaerobic digestion of goose manure. The CSTRs were run at three different organic loading rates: 1.4 g-VS/L.day, 2.9 g-VS/L.day and 4.4 g-VS/L.day, consequently termed as Phase-1, Phase-2 and Phase-3, respectively, and five different sonication pretreatments levels: (25 min, 45 min, 60 min, 90 min, and 120 min) at 28 KHz that were employed to optimize the anaerobic digestion process for goose manure to enhance methane production. The second phase was proved to be the optimum phase with maximum methane enhancement capability, CODs stabilization rate, and VS removal efficiency. Owing to thermal-sonication and organic loading management, methane enhancement up to 40.76% was evaluated for reactor C during the second phase of experiment. Furthermore, the biochemistry of the anaerobic digestion process was deeply interpreted at each three-day interval and the techno-economic analysis was performed to evaluate the pretreatment feasibility. (C) 2020 Elsevier Ltd. All rights reserved.