Analysis of Casson Fluid Flow over a Vertical Porous Surface with Chemical Reaction in the Presence of Magnetic Field

Casson fluid flow over a vertical porous surface with chemical reaction in the presence of magnetic field has been studied. A similarity analysis was used to transform the system of partial differential equations describing the problem into ordinary differential equations. The reduced system was solved using the Newton Raphson shooting method alongside the Forth-order Runge-Kutta algorithm. The results are presented graphically and in tabular form for various controlling parameters.

Manufacture of Bulk Amorphous Crystal and Micro-Crystal for Pr_(60)Cu_((20-x))Ni_(10)Al_(10)Fe_x and Characteristics of Its Magnetic Apparatus

Bulk amorphous crystal and microcrystal for Pr60Cu(20-x)Ni10Al10Fex (x = 0, 8, 15, 20) with the diameter ofΦ2 ~ 6 mm were manufactured by electric arc smelting, high frequency heating and copper mold upper suction casting, and its structure was analyzed by X-ray diffract meter. It showed soft magnetic characteristic gradually when Fe content in it was up to 8% . The material was applied to magnetic-electric sensor as key component, output signal of which was measured with the change of Fe content. It shows that the signal changes from weak to strong with the increase of Fe content and presents the largest peak value when Fe is replaced by Cu completely.

Effects of heat and mass transfer on nonlinear MHD boundary layer flow over a shrinking sheet in the presence of suction

This work is concerned with Magnetohydrodynamic viscous flow due to a shrinking sheet in the presence of suction. The cases of two dimensional and axisymmetric shrinking are discussed. The governing boundary layer equations are written into a dimensionless form by similarity transformations. The transformed coupled nonlinear ordinary differential equations are numerically solved by using an advanced numeric technique. Favorability comparisons with previously published work are presented. Numerical results for the dimensionless velocity, temperature and concentration profiles as well as for the skin friction, heat and mass transfer and deposition rate are obtained and displayed graphically for pertinent parameters to show interesting aspects of the solution.

Local non-similarity solution to impact of chemical reaction on MHD mixed convection heat and mass transfer flow over porous wedge in the presence of suction /injection

Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by the Runge-Kutta-Gill scheme with the shooting method as well as the local non-similarity method up to the third level of truncation, which are used to reduce the governing partial differential equations into nine ordinary differential equations. The governing boundary layer equations are converted to a dimensionless form by Falkner-Skan transformations. Because of the effect of suction/injection on the wall of the wedge with buoyancy force and variable wall temperature, the flow field is locally non-similar. Numerical calculations up to the third order level of truncation are carried out as a special case for different values of dimensionless parameters. Effects of the magnetic field strength in the presence of chemical reaction with variable wall temperature and concentration on the dimensionless velocity, temperature and concentration profiles are shown graphically.

抽油管的在线漏磁检测技术

由于复杂的工况,抽油管的内、外壁极易发生损伤。目前,抽油管的检测方式主要是将抽油管抽离油井后送至后线检测场地进行检测,造成了时间、人力、物力的浪费。采用漏磁检测方法,开展了抽油管在起管或下管过程中的在线检测;设计了瓦片式磁化结构,建立抽油管漏磁检测的三维仿真模型;针对抽油管的腐蚀缺陷,改变缺陷尺寸参数,研究了缺陷漏磁场的分布特性;研发了抽油管在线漏磁检测系统,在实验室和油田作业现场对抽油管进行在线检测试验。试验结果表明,该系统能够快速高效地完成抽油管的在线检测,为抽油管的损伤监测提供了一些参考。

基于磁耦合传动的吸痰装置的研制与验证

目的 针对以往吸痰装置的人工气道内吸痰中送、退管的核心操作,研制新一代稳定、安全的吸痰装置,以代替护理人员完成吸痰操作。方法 在上一代仿真吸痰机器人研发已取得送、退吸痰管的推拉力、速度、时间等相关参数的基础上,通过使用磁耦合传动和滚轴输送,实现非接触动力传递和卡顿减少,确保吸痰管送退的稳定性;通过在建立人工气道的吸痰练习模型上进行可行性训练,确保吸痰装置使用的有效性和安全性。结果 可行性训练表示,在20次有效性模拟实验中,有17次实验可成功吸出模拟痰液约5~9 mL,平均可抽出约7.5 mL痰液;在10次安全性模拟实验中,吸痰装置与手动吸痰在送、退吸痰管时的推力、拉力和旋转力无明显统计学差异(P>0.05),且吸痰装置数据更为稳定。结论 该吸痰装置可稳定安全地传送和退出吸痰管,有效完成吸痰操作,且便于拆卸、清洗和消毒,可有效减轻医护人员的工作负担。

Thermal Radiation Effect on the MHD Turbulent Compressible Boundary Layer Flow with Adverse Pressure Gradient, Heat Transfer and Local Suction

The combined effect of magnetic field, thermal radiation and local suction on the steady turbulent compressible boundary layer flow with adverse pressure gradient is numerically studied. The magnetic field is constant and applied transversely to the direction of the flow. The fluid is subjected to a localized suction and is considered as a radiative optically thin gray fluid. The Reynolds Averaged Boundary Layer (RABL) equations with appropriate boundary conditions are transformed using the compressible Falkner Skan transformation. The nonlinear and coupled system of partial differential equations (PDEs) is solved using the Keller box method. For the eddy-kinematic viscosity the Baldwin Lomax turbulent model and for the turbulent Prandtl number the extended Kays Crawford model are used. The numerical results show that the flow field can be controlled by the combined effect of the applied magnetic field, thermal radiation, and localized suction, moving the separation point, xs , downstream towards the plate’s end, and increasing total drag, D . The combined effect of thermal radiation and magnetic field has a cooling effect on the fluid at the wall vicinity. The combined effect has a greater influence in the case of high free-stream temperature.

Hall Effects on Unsteady Magnetohydrodynamic Flow of a Third Grade Fluid

The unsteady magnetohydrodynamic flow of an electrically conducting viscous incompressible third grade fluid bounded by an infinite porous plate is studied with the Hall effect. An external uniform magnetic field is applied perpendicular to the plate and the fluid motion is subjected to a uniform suction and injection. Similarity transformations are employed to reduce the non-linear equations governing the flow under discussion to two ordinary differential equations （with and without dispersion terms）. Using the finite difference scheme, numerical solutions represented by graphs with reference to the various involved parameters of interest are discussed and appropriate conclusions are drawn.

基于永磁直驱用电磁制动器的设计与研究

针对永磁直驱用电磁制动器制动力大、体积大、发热严重等问题,通过场路结合的方法,简化求解电磁吸力,运用Ansys有限元软件对电磁制动器进行场域求解分析,研究电磁制动器结构尺寸、气隙、绕组匝数、高压吸合时间、低压保持电压等参数对其性能的影响,并设计了一台220 kN的电磁制动器,通过样机的试验验证了计算和分析的正确性。

微型涡旋压缩机轴向力曲线匹配吸力足机构优化研究

微型涡旋压缩机的轴向气体力随主轴转角而大幅度变化,存在难以实现良好的轴向密封等问题,为此,提出了一种基于永磁体的轴向磁力平衡轴向气体力的吸力足机构。首先,对微型涡旋压缩机的轴向气体力进行了特性分析,确定了目标轴向气体力曲线;其次,基于JMAG建立了三维仿真模型,采用遗传算法对永磁体的位置进行了优化,由此达到了轴向力变化趋势最大的目标;再次,在永磁体位置优化基础上,提出并对比了4种不同的吸力足分块方案,改变了分块吸力足的高度来匹配随动涡盘平动而变化目标的轴向力曲线;最终,对选择方案的分块吸力足高度敏感性进行了分析,固定了敏感性低的分块高度,降低了实际制作和装配的复杂性;通过仿真和实验测试,对优化后吸力足机构轴向力的准确性进行了验证。研究结果表明:改变永磁体在静环的位置,轴向力的最大值提升27.56%;在所有分块方案中,分块数越多,吸力足机构平衡效果越佳,且周向切割优于径向切割,周向切割最优结构的积分差相较于径向切割方案减小了42.91%;经实验验证后,优化的吸力足机构的最大误差仅为6.2%,与仿真结果具有良好的一致性,很大程度上解决了微型涡旋压缩机的轴向密封问题。

五行磁吸针联合经络导平刺激治疗小儿脑性瘫痪的临床效果

目的探讨五行磁吸针联合经络导平刺激治疗小儿脑性瘫痪的临床效果。方法回顾性分析2021年1月至2023年12月于西安交通大学第二附属医院接受诊治的160例脑瘫患儿的临床资料,按照门诊或住院号末位数字奇偶数将其分为对照组和试验A、B、C组,每组40例。对照组接受常规康复训练,试验A组在对照组基础上进行五行磁吸针疗法,试验B组在对照组基础上进行经络导平刺激治疗,试验C组在对照组基础上同时进行五行磁吸针疗法以及经络导平刺激治疗。比较各组的治疗效果。结果治疗后,试验A、C组的脑瘫综合功能评分高于对照组(P<0.05);试验A、B、C组的恢复率高于对照组(P<0.05)。治疗后,试验C组的残疾程度低于治疗前(P<0.05)。试验A、B、C组的治疗总有效率明显高于对照组(P<0.05)。治疗后,各组的C反应蛋白(CRP)、白细胞介素-6(IL-6)水平明显低于治疗前,神经生长因子(NGF)水平明显高于治疗前(P<0.05);治疗后,试验A、B、C组的CRP、IL-6水平低于对照组,NGF水平高于对照组(P<0.05)。结论五行磁吸针联合经络导平刺激治疗能够显著改善脑瘫患儿的残疾障碍,提高临床治疗效果,为患儿带来更大的生存获益;动态观察血清CRP、IL-6、NGF水平变化对脑瘫患儿的病情判断、临床诊断、预后评估等具有参考价值。

变压器油温测量中的磁吸型辅助保护装置研究

受恶劣天气、积尘积潮和油渍污垢的影响,变压器油温测量过程中容易出现表盘损坏、读数错误、示数不准确等问题。研究从表计保护罩原理出发,设计一款适用于现场表计环境保护的磁吸型装置,其箱体由轻质防腐蚀材料制成,制作镀层,涂漆防锈;箱外设置磁吸式连接件,可直接与现场装置通过磁力吸附或卡接,增强了箱罩的稳定性和可靠性;箱面设置可视窗口或直接空置,便于现场读数。该装置安装便捷、操作简单且成本低廉,适用范围较广,具有切实的研究意义和实用价值。

一种新型1000MW超临界锅炉水冷壁爬壁机器人结构设计

锅炉水冷壁稳定运行是火电厂安全生产的重要保障,目前国内外锅炉水冷壁的巡检工作主要以目视检验、卡尺测量、超声波测厚仪检测壁厚、电筒照射检查等人工方式进行,巡检周期长且精度低。文章结合计算机视觉、电磁超声无损检测、自动化等技术,设计了一种新型的锅炉水冷壁爬壁机器人,致力于解决困扰火电行业已久的缺少有效评估检查锅炉水冷壁外观磨损及内部腐蚀状态的评估问题。

磁控式真空装置中永磁体的磁场分析

针对现有真空吸取装置高能耗问题提出一种磁控式扩容真空发生-吸取集成的解决方案。通过COMSOL进行磁场仿真分析,研究不同磁块形状、分布半径和轴向距离对轴向永磁体之间磁力的影响。仿真结果显示:在选定的4种磁块排布方式中,圆柱体磁块排布方式的轴向磁力最大,且磁块之间需要分离排布才能实现最大的轴向磁力,但分布半径进一步增加,磁力F_(τ)变化量较小,可以忽略不计。采用N38钕铁硼磁块、厚度10 mm、直径φ20 mm的圆柱体磁块进行试验,测量磁块不同轴向距离和分布半径下磁力的大小。试验结果验证了仿真结果,同时表明:磁块间的磁力绝对值与轴向距离成负相关;轴向距离为5 mm、分布半径为17 mm时产生的最大磁吸力为109.7 N,最大磁斥力为88.71 N,可以满足磁控式扩容真空装置的工作需求。

吸引式输尿管支架与常规输尿管支架治疗泌尿系结石的疗效及安全性比较

目的比较吸引式输尿管支架和常规输尿管支架在泌尿系结石患者治疗中的疗效及安全性,以评估吸引式输尿管支架的临床应用价值。方法回顾性分析黄石市中心医院2022年12月—2023年5月收治的196例行输尿管硬镜或软镜钬激光碎石术的泌尿系结石患者,术中使用吸引式输尿管支架(吸引式输尿管支架组)100例,常规输尿管支架(常规组)96例。比较两组患者术前一般资料,拔管时的视觉模拟评分(VAS)、拔管时间、拔管成功率,以及拔管后有无肉眼血尿、腰腹部疼痛和泌尿系感染等指标。结果在拔管过程中,吸引式输尿管支架组较常规组的VAS评分低[(2.94±1.24)分vs.(5.78±1.50)分],拔管时间短[(4.28±0.51)min vs.(13.51±1.81)min],差异有统计学意义(P<0.01)。在拔管后,吸引式输尿管支架组较常规组并发症发生率更低(P<0.05)。结论在泌尿系结石治疗中,采用吸引式输尿管支架相较于常规输尿管支架具有操作简便、患者舒适性高、并发症少、拔管时间短和医疗费用少等优势。

交流电磁铁短路环的设计

为了解决接触器动、静铁心出现的频率振动问题,接触器交流电磁系统通常是在铁心上增加短路环。介绍了接触器交流电磁系统铁心短路环的作用及其工作原理,分析了短路环的结构参数对铁心最小吸力及平均吸力的影响。着重阐述了短路环内、外磁通相位差对短路环性能的影响,给出了基于此磁通相位差来确定短路环综合参数的方法,同时通过数值计算予以理论论证,并以实际接触器研发应用证明了此设计方法的有效性。

育苗精量播种机研究现状及发展分析

育苗精量播种机是育苗机械化生产的关键设备,其播种效率高,可为水稻、蔬菜、花卉等小粒种子现代化和工厂化育苗提供可能。通过对国内外气力板式、针式、滚筒式精量播种机研究现状、产品特点、新型播种技术研究进展的介绍,分析我国育苗播种机在播种稳定性、气密性精准控制、机艺融合方面存在的问题,提出通过引进吸收、技术创新突破关键参数控制,加强机艺融合等途径,提高我国精量播种机作业稳定性、可靠性和自动化水平,为我国进一步研制、推广应用育苗精量播种机和精播流水线提供参考。

强吸力钕铁硼永磁起重机

介绍了钕铁硼永磁起重机的基本结构和工作原理 ,利用高性能钕铁硼研制开发的永磁起重机 ,其工作极面吸力达到了 2 6 2kg/cm2 ,自重比达到了 1∶1 5 0 ,具有高效、节能、强吸力和高可靠性等特点 。

抗血栓药物致脑出血的立体定向血肿抽吸治疗

目的探讨立体定向血肿抽吸术联合药物治疗在抗血栓药物致脑出血患者治疗中的应用及疗效，以为临床提供更为合理的治疗方案。方法24例抗血栓药物致脑出血患者，12例经立体定向血肿抽吸术联合药物治疗（联合治疗组），其余12例单纯予以药物治疗（对照组）；分别采用Barthel指数评分和GOS预后分级对生存者日常生活活动能力和预后进行评价。结果联合治疗组患者颅内血肿明显缩小，其中治疗后3d血肿基本清除者5例，治疗后5d血肿清除者6例，治疗后7d血肿清除者1例；而对照组治疗后3d无一例血肿缩小，头部CT检查显示血肿周围呈低密度改变。发病后6个月，联合治疗组和对照组患者Barthel指数评分分别为（60．42±39．40）分和（29．58±32．01）分，两组日常生活活动能力比较差异具有统计学意义（t=2．104，P=0．047）；联合治疗组患者GOS预后分级达满意者7例（7／12），对照组2例（2／12），两组比较差异具有统计学意义（P=0．045）；联合治疗组死亡2例（2／12），而对照组死亡4例（4／12）。结论在病情严重程度相似的情况下，立体定向血肿抽吸术联合药物治疗的临床效果优于单纯药物治疗。

模块化磁吸五指灵巧手结构设计与控制研究

针对目前五指灵巧手自由度低、拆装繁琐等问题,设计出一种模块化、易拆装、直驱式11自由度五指灵巧手。通过永磁铁实现手指关节间的快速拆装,每个手指关节至少有±90°转动范围;通过对大拇指转动角度的特殊设计,可实现灵巧手左/右手模式直接切换以及双侧同时抓取。通过3D打印制作了五指灵巧手样机。针对灵巧手多传感器造成控制系统复杂的问题,提出采用电流反馈控制算法,通过对电机驱动电流进行信号采集和后处理,建立了电流-转角-指尖力之间的数学模型,并进行了抓取实验。结果表明,设计的模块化灵巧手具有较强的抓取能力,并且通过电流反馈控制算法,可以实现对灵巧手运动状态和抓取力的控制,完成对目标物抓取操作。