Morphology,adipocyte size,and fatty acid analysis of dairy cattle digital cushions,and the effect of body condition score and age

The digital cushion is an essential part of maintaining a healthy foot, working to dissipate foot strike and body weight forces and lameness from claw horn disruption lesions. Despite the importance of the digital cushion, little is known about the basic anatomy, adipocyte morphology, and fatty acid composition in relation to age, limb position, and body condition score. In total, 60 claws (from 17 cows) were selected and collected from a herd, ensuring that body condition score data and computed micro-tomography were known for each animal. Digital cushion tissue underwent histological staining combined with stereology, systematic random sampling, and cell morphology analysis, in addition to lipid extraction followed by fatty acid analysis. The results describe digital cushion architecture and adipocyte sizes. Adipocyte size was similar across all 4 claws (distal left lateral and medial and distal right lateral and medial) and across the ages (aged 2–7 yr); however, animals with body condition score of 3.00 or more at slaughter had a significantly increased cell size in comparison to those with a score of less than 2.50. Of 37 fatty acid methyl esters identified, 5 differed between either the body condition score or different age groups. C10:0 capric acid, C14:0 myristic acid, C15:0 pentadecanoic acid, and C20:0 arachidic acid percentages were all lesser in lower body condition score cows, whereas C22:1n-9 erucic acid measurements were lesser in younger cows. Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid percentages were not altered in the different claws, ages, or body condition score groups. Triglyceride quantities did not differ for claw position or age but had decreased quantities in lower body condition score animals. Digital cushion anatomy, cellular morphology, and fatty acid composition have been described in general and also in animals with differing ages, body condition scores, and in the differing claws. Understanding fat deposition, mobilization, and composition are essential in not only understanding the roles that the digital cushion plays but also in preventing disorders and maintaining cattle health and welfare.     

桩土复合路基静载试验改进方法研究

静载试验作为复合路基的一种重要检测手段而广泛应用,然而,在工程质量检测中,常出现检测结果与实际情况不符的情况,除人为操作因素外,垫层模拟过于简单是主要原因。借助引入弹性垫层,提出一种桩土复合路基静载试验改进方法。首先,基于数值模拟计算,建立复合路基桩土应力比n和桩土相对位移Δs、弹性垫层厚度h和弹性垫层模量E的函数关系;其次,通过模拟结果和路堤荷载结果对比,确定不同桩型复合路基静载试验中弹性垫层参数选择范围,最后,利用现场对比试验和实测结果,论证桩土复合路基静载试验改进方法的正确性和可靠性。     

考虑水平（切向）位移影响的垫层孔隙内土工膜顶胀

The common cushion layer used in the geomembrane face rockfill dam is made of granular materials such as gravel and non-fine concrete where bulge deformation or failure of geomembrane is very likely to occur in its surface holes. The curve intersection method based on the thin film theory is the common method used to analyze the bulge deformation of the geomembrane in the surface holes of cushion layer. However, it is inaccurate due to the neglection of horizontal (tangential) displacement of the geomembrane. Based on the FEM theory, a new method is proposed, which takes the horizontal (tangential) displacement of geomembrane into consideration, and is validated by the bulge tests on the geomembrane in a circular hole. The deformations and strains of the geomembrane in different shapes of holes are analyzed by this method, and different strain distributions and failure modes are obtained. The curve intersection method is also used to compare with the new method under the same condition. It is indicated that there is less difference in the deformation and average strain of the geomembrane when the water pressure is low. However, when the water pressure is relatively high, the influences of horizontal (tangential) displacement of the geomembrane on its strain should not be neglected.     

换土垫层厚度的直接算法

本文对直接计算条形基础和短形基础换土垫层厚度的方法进行了探讨，建立力平衡方程直接计算，可不需试算就可直接算出换土垫层厚度。     

矿石垫层消波分析实验

在激波管内充填高压气体模拟矿顶冒落后产生的高压气浪，充填块石模拟矿石垫层。对不同厚度、不同孔隙率的垫层的消波作用进行了试验，并在矿山进行了现场实验，得出了一致的规律。获得了垫层厚度的确定方法。     

CFG桩复合地基褥垫层工作性状研究

总结了刚性基础下CFG桩复合地基中褥垫层的作用机理，采用数值模拟的方法研究了柔性基础下褥垫层的不同工作特点，对褥垫层的合理设置提出了几点建议。     

CFG桩复合地基褥垫层的合理厚度确定方法研究

在CFG桩复合地基设计中，褥垫层的厚度设计是一个重点，它是复合地基承载力能否全部发挥的关键因素之一。但其设计上基本是靠经验取值，缺少理论根据。从理论方面入手，推导了褥垫层厚度的理论计算方法，给出了最佳垫层厚度、桩土应力比的解析表达式。     

步行轮式气垫车行驶过程动态数字仿真研究

首次应用数字仿真方法对步行轮式气垫车在软地面行驶过程进行了动态数字仿真,应用系统分析方法建立了该系统的运动微分方程,提出了运输生产率、运输效率、垫升比功率、等效运动阻力系数和升沉加速度最大值等性能评价指标,确定了目标函数。对步行轮轮轴相对车体的位置进行了优化,并对软地表进行了随机数字仿真,编制了步行轮式气垫车在软地面行驶过程的大型动态仿真程序包。     

仿步行式气垫车辆转向时的运动性能和动力性能分析

对仿步行式气垫车辆的转向进行了运动分析和受力分析，给出了仿步行式气垫车实现稳定转向的条件，仿步行式气垫车用双向液压马达驱动、通过分－集流阀改变双侧液压马达流量来控制内，外侧轮的下，反转，从而实现车辆的转向，提出用同步阀控制两侧半步行轮的同步运动、在气垫车前部安装导向盘等措施来保证其直线行驶性能。     

水泥土搅拌桩的加固机理及其应用

水泥土桩加固软土地基，一般形成半刚性桩复合地基。从水泥土桩复合地基的构成，对水泥土桩桩身、垫层及桩间土的受力特性及相互作用机理进行了分析和探讨，同时对水泥土搅拌桩复合地基的设计理论进行了阐述，对施工方案及施工注意事项提出相关建议。