玉米秸秆的压缩特性及其压力与压缩密度的数学模型   总被引：1，自引：0，他引：1  

王波  李汝莘  高丽霞  赵毅彬  何伟宁 《农机化研究》2005,(2):160-162,166

目前,秸秆青贮主要采取地下青贮的方式,工序比较多,劳动强度大,秸秆浪费严重,甚至易发生霉变。如果对揉搓后的秸秆能够进行压缩打捆,用塑料薄膜密封后在地上贮存,将会使上述问题得到较好的解决。为此,对揉搓后玉米秸秆在闭式容器内进行了压缩试验,并对揉搓后玉米秸秆的压力-变形曲线进行分析。结果表明,揉切后玉米秸秆的压缩过程存在松散、过渡和压紧3个阶段。进一步对试验数据进行统计分析,建立了揉搓后玉米秸秆的压力P与压缩密度γ在松散阶段、过渡阶段和压紧阶段的数学模型。  相似文献   

枣树修剪枝条弯曲及压缩特性研究     

雷世博  丁龙朋  李景彬  阿依肯·叶留拜 《农机化研究》2022,44(5):198-203

为解决密植枣园枝条粉碎还田机粉碎装置设计和枣树修剪枝条数值化建模缺乏部分关键力学参数和理论基础的问题,以十四师224团枣树修剪枝条为研究对象,采用8801型万能试验机进行了弯曲和压缩试验.设计了三因素五水平正交试验,研究了标距跨度、加载速度、取样部位对枣树修剪枝条弯曲性能的影响;设计了单因素试验,研究了压缩速度、压缩方...  相似文献   

Pathological effects of Cichlidogyrus philander Douëllou, 1993 (Monogenea,Ancyrocephalidae) on the gills of Pseudocrenilabrus philander (Weber, 1897) (Cichlidae)     

Patience Chwe Igeh  Annemariè Avenant-Oldewage 《Journal of fish diseases》2020,43(2):177-184

Histopathological changes of Cichlidogyrus philander Douëllou, 1993 on the gills of Pseudocrenilabrus philander (Weber, 1897) were studied using light and scanning electron microscopy. Observations revealed that C. philander attaches to its host by alternating the prohaptor (for temporary attachment or feeding) or haptor (using haptoral parts for firm and secured attachment). The sharp terminal ends of the anchors are inserted basally into the gill lamella, between two adjacent secondary gill lamellae and the marginal hooklets assist by superficially penetrating, holding and lifting epithelial tissue in the proximal region of the secondary gill lamella. The attachment of C. philander resulted in compression, rupturing of the interlamellar epithelium, change in the organization of epithelial cells in both primary and secondary gill lamella, displacement of the extracellular cartilaginous matrix, occasional rupturing of blood vessels and erythrocytes and some cells becoming ill-defined. At the site of attachment, the host response comprises of hyperplasia, increase in the number of mucous cells and infiltration with neutrophils. It was concluded that the effect of C. philander is mild in natural conditions.  相似文献   

Movement and thermal niche of the first satellite‐tagged Mediterranean spearfish (Tetrapturus belone)     

Martin C. Arostegui  Camrin D. Braun  Peter Gaube 《Fisheries Oceanography》2019,28(3):327-333

The Mediterranean spearfish (Tetrapturus belone) is one of the least‐studied istiophorid billfishes, with little known of its biology, ecology, and behavior. To assess the species’ movement and thermal niche, we analyzed telemetry data from, to our knowledge, the first and only Mediterranean spearfish ever outfitted with a pop‐up satellite archival transmitting tag. Throughout a 29‐day deployment during July and August 2015, the fish travelled in Italian waters of the Tyrrhenian and Ligurian Seas, spending on average 93% of each 24‐hr period above 30 m and exhibiting a diel activity pattern comprised of daytime vertical movement and nighttime near‐surface residency. The preferred thermal niche was 26–28°C, but the spearfish experienced temperatures as low as 14.2°C during descents. Vertical distribution was limited throughout the deployment with more time spent at depth in areas where the thermocline was comparatively deeper and weaker, consistent with habitat compression experienced by other billfishes.  相似文献   

One Dimension Compression Model for Natural Clays Considering Structure Disturbance     

ZHU Qiyin  YIN Zhenyu  WANG Jianhua  XIA Xiaohe 《保鲜与加工》2012,(3):28-33

In order to investigate the 1D (one dimensional) compression behavior for China structured clays in a simple way, the experimental results on intact and reconstituted clay samples for 12 typical China natural clays located from south to north in China were analyzed. Based on these, a modeling method for destructuration behavior was proposed by introducing the bonding ratio and furthermore extended to disturbance soil model by using disturbance state concept. The proposed model was then validated by simulating 1D compression tests of various natural clays.  相似文献   

基于ANSYS的鸡毛菜茎秆切割的有限元分析及验证试验     

刘东  肖宏儒  金月  杨光 《中国农业科技导报》2018,20(11):85-93

鸡毛菜切割部件是鸡毛菜有序收获过程中的关键部件,为了降低有序收获过程中的损失率和损伤率,提高收获效率,采用静态测量法,应用质构仪对鸡毛菜茎秆在压缩条件下的一系列力学特性参数进行测定分析,得到在压缩条件下鸡毛菜茎秆轴向弹性模量范围为3.15~3.91 MPa,径向弹性模量范围为20.24~20.99 MPa。结合试验所得鸡毛菜茎秆力学特性相关数值在有限元分析软件ANSYS中建立鸡毛菜茎秆材料库,再利用三维建模软件SolidWorks建立切割过程模型,将之导入ANSYS中进行显示动力学分析,并对有限元分析所得结果进行田间试验验证,对比结果显示：当割刀往复速度v大于0.40 m/s时,能有效完成对鸡毛菜茎秆的切断过程,且割茬整齐、断口平滑、无扯皮现象,分析结果为后续鸡毛菜切割部件的设计及参数优化提供理论依据。  相似文献   

带约束拉杆钢管/竹胶板组合空芯短柱的偏心抗压性能   总被引：1，自引：1，他引：0  

赵卫锋  谷伟  周靖  龙志林 《农业工程学报》2016,32(15):75-82

采用冷弯薄壁方型钢管和胶合竹板通过横向约束拉杆和结构胶黏剂复合成顺纹抗压的组合空芯短柱(thin-walled steel tube/bamboo-plywood composite hollow short column with binding bars,SBCCB),采用9个试件研究SBCCB试件的偏心抗压破坏模式、抗压承载力和影响规律。结果表明,SBCCB试件受压破坏形态主要为柱端开胶破坏、横向约束拉杆之间基体胶合界面开胶剥离破坏和胶合竹板局部压屈破坏;SBCCB抗压极限荷载随胶合竹净横截面积增大而提高,随着长细比和荷载偏心率的增大而降低,随空心率增大而增大;约束拉杆可有效延迟SBCCB的开胶剥离破坏,改变屈曲破坏模式,有助于试件抗压承载力的提高;相对于不带约束拉杆试件,SBCCB抗压极限应力提高约17.64%;局部翘曲随约束拉杆间距减小而减小,相对拉杆间距比3.0以下能确保较小的局部翘曲变形。薄壁钢管和胶合竹板能形成较好的复合抗压结构单元,该批试件平均值抗压强度达到18.54 MPa,展现了优异的抗压性能。SBCCB可作为绿色建筑材料广泛应用于现代装配式工程结构,同时拓展竹材的应用途径,实现"以竹代木,以竹代钢",具有很好的工程价值和应用前景。  相似文献   

荔枝挤压损伤有限元预测分析     

李嘉威  陈燕  蒋志林  邹湘军  彭红星  王佳盛 《河南农业科学》2016,(11):145-148

为减小荔枝的挤压损伤,通过试验测定了荔枝果壳和果肉的极限应力,建立了根据荔枝结构所对应的有限元模型,模拟了外力沿不同方向挤压荔枝的过程,得到荔枝内部组织的等效应力云图。结果显示:挤压过程中,荔枝果壳的应力大于果肉,果肉的损伤先于果壳;相同挤压力下,果壳的纵向挤压应力小于横向,但果肉的纵向挤压应力却大于横向;荔枝的挤压损伤具有各向异性,试验范围内,果肉出现机械损伤的纵向和横向挤压力分别为10 N和20 N,果壳出现机械损伤的纵向和横向挤压力为35 N和25 N。  相似文献   

偏压构件在农业建筑结构中的应用研究     

何章权  杨智良  王强 《安徽农业科学》2016,(8)

在现代农业工程中,混凝土类构件应用广泛,可使用混凝土构件预制或现浇构件作为农业类建筑,如农业大棚、农业仓库等建筑的竖向受力构件。就农业建筑结构的柱类构件进行理论分析,讨论该类构件在实际工程中的应用及设计方法。以合肥地区某生产蔬菜的农业大棚为例,分析大偏压构件和小偏压构件的计算分析和在实际工程中的应用情况。对此类构件的设计原理进行正确的分析,可以安全、经济、有效地指导农业类建筑的结构设计。  相似文献   

稻草秸秆压缩特性研究   总被引：2，自引：0，他引：2  

刘新柱  王玉花  韩平  刘向东  姚嘉  栾积毅 《农机化研究》2016,(6):225-229

将农作物秸秆收获及打成高密度草捆是其合理应用重要的第1步。为了合理开发利用稻草秸秆这一类型生物质资源,结合自制密闭压力容器,在电子万能试验机上对同一类型、不同长度的稻草秸秆以不同的压缩速度进行了闭式压缩试验;分析了秸秆捆在压缩后密度相同情况下秸秆长度和压缩速度对压缩力的影响,建立了其数学模型。结果表明:当压缩密度相同时,秸秆越长、压缩速度越快,所需压缩力也越大。由此为设计、制造高性能的稻草秸秆打捆机提供了必要的理论依据。  相似文献