奶牛乳腺炎智能检测仪的设计与研究

为了及时、准确地检测出奶牛的乳腺炎，本文根据奶牛感染乳腺炎引起乳汁电导率和pH值变化的原理，设计出了一种基于单片机控制的智能型奶牛乳腺炎自动检测仪。该仪器能够根据乳汁电导率和pH实测值的大小判断出奶牛是否感染乳腺炎，并由专家系统给出相应的治疗措施，同时可由仪器的时钟系统和温度测量系统分别将测量时间和测量时乳汁的温度记录下来，并保存在单片机系统的存储器中（或通过RS485通讯接口传输到PC机保存）。通过对一段时间内的测量值进行分析可以制定出相应的营养方案和管理方案。该仪器既能独立使用又能安装在自动挤奶系统来实现在挤奶的同时对乳腺炎的在线检测。实验表明：本仪器具有快速、准确、检测成本低、使用简单方便的特点，该检测仪对临床乳腺炎检测的正确率为94％，对隐性乳腺炎检测的正确率为67％。     

Online conductivity calibration methods for EIT gas/oil in water flow measurement

Electrical Impedance Tomography (EIT) is a fast imaging technique displaying the electrical conductivity contrast of multiphase flow. It is increasingly utilised for industrial process measurement and control. In principle, EIT has to obtain the prior information of homogenous continuous phase in terms of conductivity as a reference benchmark. This reference significantly influences the quality of subsequent multiphase flow measurement. During dynamic industrial process, the conductivity of continuous phase varies due to the effects from the changes of ambient and fluid temperature, ionic concentration, and internal energy conversion in fluid. It is not practical to stop industrial process frequently and measure the conductivity of continuous phase for taking the EIT reference. If without monitoring conductivity of continuous phase, EIT cannot present accurate and useful measurement results. To online calibrate the electrical conductivity of continuous phase and eliminate drift error of EIT measurement, two methods are discussed in this paper. Based on the linear approximation between fluid temperature and conductivity, the first method monitors fluid temperature and indirectly calibrates conductivity. In the second method, a novel conductivity cell is designed. It consists of a gravitational separation chamber with refreshing bypass and grounded shielding plate. The conductivity of continuous phase is directly sensed by the conductivity cell and fed to EIT system for online calibration. Both static and dynamic experiments were conducted to demonstrate the function and accuracy the conductivity cell.     

一种军械油料快速检测方法研究

本文采用YX1154油料电导率测定仪研究了组分变化对45号变压器油和通用装备液压油两种油料电导率的影响,探索了电导率与传统测试指标的相关性。结果表明：油料电导率随防锈剂含量变化呈线性增加,并且与抗腐蚀性能测定结果一致。因此,该方法不仅可用于军用油料的生产质量检测和库存质量监控,而且可作为野战条件下评价油料性能的快速检测方法。     

一种军械油料快速检测方法研究

本文采用YX1154油料电导率测定仪研究了组分变化对45号变压器油和通用装备液压油两种油料电导率的影响，探索了电导率与传统测试指标的相关性。结果表明：油料电导率随防锈剂含量变化呈线性增加，并且与抗腐蚀性能测定结果一致。因此，该方法不仅可用于军用油料的生产质量检测和库存质量监控，而且可作为野战条件下评价油料性能的快速检测方法。     

Measuring inline velocity profile of shampoo by electrical resistance tomography (ERT)

The rheological properties of fluid systems govern the efficiency and quality of a production process. For certain materials, i.e. non-Newtonian fluids, The change in shear rate leads to the change of local viscosity, while the conductivity also changes due to the change in micro-structure of the material by varying shear rate. This paper provides a method of measuring the local velocity of shampoo in an in-line pipeline loop using electrical resistance tomography (ERT). Boundary voltages are measured by ITS P2000 ERT system and processed into a 2-D conductivity distribution in a MATLAB based ERT tool kitEIDORS. Linear-back projection (LBP) method is used for solving the inverse problem. The change in shear rate leads to a micro-structure change in the shampoo, resulting in an annular conductivity distribution in the cross-sectional view of the pipeline. By varying the flow rate, different changes in conductivity can be obtained. A velocity profile of shampoo is calculated based on the change in conductivity, giving a method to realise in-line rheometer by ERT.     

分布式无线土壤电导率测量装置的设计

采用电流电压四端法设计一种多点无线传输的土壤电导率测量装置.硬件部分采用TDR-4传感器的四针微型探头可减小对溶质运移的扰动,且可高密度分布在土壤中,系统连接多路电导率探头和8位高精度数据转换器能够实现多通道土壤电导率测量,并通过无线模块实现系统规模的扩展,采用主从式结构测量显示平台能够完成数据采集、显示与存储功能,有效解决了多点土壤电导率实时监测的一致性问题.试验结果表明:系统具有良好的稳定性,土壤电导率与含盐量呈线性变化.     

Electrical Conductivity and Friction Force Estimation in Compliant Electrical Connectors

The electrical conductivity and friction force of a compliant curved beam loaded by a rigid flat surface which simulate electrical connectors in high-tech applications is analyzed. Both the elastic deformation of the curved beam and elastic-plastic deformation of the asperities are considered. The effects of the applied load, the surface hardness and roughness as well as the beam geometry on the electrical conductivity and friction are investigated. It is found that the electrical conductivity is insensitive to changes in the beamís geometry like its angular span and slender ratio. Surface roughness and hardness affect both electrical conductivity and friction.     

Wire electrical discharge machining of ASP30 tool steel

Wire electrical discharge machining is a non-traditional cutting process for machining of hard and high strength materials. This study analyzed the effects of the main input parameters of wire electrical discharge machining of ASP30 steel (high alloyed Powder metallurgical [PM] high speed steel) as the workpiece on the material removal rate and surface roughness. The input parameters included spraying pressure and electric conductivity coefficient of the dielectric fluid, linear velocity of the wire and wire tension. The machined surface quality was evaluated using SEM pictures. Results indicated that increasing the spraying pressure of dielectric fluid leads to a higher material removal rate and surface roughness and that increasing the wire tension, linear velocity of wire, and electric conductivity of the dielectric fluid decreases the material removal rate and surface roughness.

     

Resonant torsional apparatus for contactless measurements of electrical conductivity and magnetic susceptibility of solids

We have constructed a torsional resonance apparatus for contact-free measurements of the electrical conductivity of solids. Owing to its use of modulation spectroscopy, the technique achieves considerable enhancement of sensitivity compared to previous contactless methods. Conductivities in the range 10(-5) mho/cm to 10(-6) mho/cm can now be measured by the contactless technique. Measurements of magnetic susceptibility as low as 10(-12) can be made. This sensitivity allows for investigation of magnetic impurities as dilute as 1 part in 10(7). In samples which display both phenomena of electrical conductivity and magnetic susceptibility, the two effects can be sorted out via analysis of frequency and/or temperature dependence. The present apparatus has potential for considerable improvement.     

A cell for preparation of solutions and simultaneous investigation of their electrical conductivity,optical density,and viscosity

A measuring cell has been designed for fast preparation of multicomponent solutions and express characterization of them in three parameters: their electrical conductivity, optical density, and viscosity. The relative error in determining the electrical conductivity and the optical density is 5–10%, and the error of viscosity measurements is 10–20%. This cell is best suited for construction of two-and multicomponent diagrams of the state in systems in which emulsions or micellar, liquid-crystal, or nanostructured liquid phases are formed.     

Influence of the electrical conductivity of dielectric on WEDM of sintered carbide

This work deals with the electrical conductivity of dielectric and cobalt percentage on output parameters such as metal removal rate and surface roughness value of sintered carbides cut by wire-electrical discharge machining (WEDM). To obtain a precise workpiece with good quality, some extra repetitive finish cuts along the rough cutting contour are necessary. Experimental results show that increases of cobalt amount in carbides affects the metal removal rate and worsens the surface quality as a greater quantity of solidified metal deposits on the eroded surface. Lower electrical conductivity of the dielectric results in a higher metal removal rate as the gap between wire electrode and workpiece reduced. Especially, the surface characteristics of rough-cut workpiece and wire electrode were analyzed too. To obtain a good surface equality without crack, 4 finish-cuts were necessary by reducing the electrical energy and the offset value.     

Effect of friction stir processing parameters on the microstructural and electrical properties of copper

Friction stir processing (FSP) is an innovative technology, based on friction stir welding (FSW) operative principles, which can be used for changing locally the microstructure and the mechanical properties of conventional materials. In this work, the copper alloy C12200 was friction stir processed using two distinct tools, i.e. a scrolled and a conical shoulder tool, in order to promote different thermomechanical conditions inside the stirred volume, and consequently, varied post-processed microstructures. The influence of the tool geometry and tool rotation and traverse speeds on the microstructural and electrical properties of the processed copper alloy was analysed. The processing conditions were found to have an important influence on the electrical conductivity of the processed material. The differences in electrical conductivity were explained based on dislocations density effects. The effect of the dislocations density on electrical conductivity of the processed material was found to prevail over the effect of the grain boundaries.     

Isochoric heating of foamed metal using pulsed power discharge as a making technique of warm dense matter

To generate well-defined warm dense state for evaluating electrical conductivity by using pulsed-power discharge, we have proposed an isochoric heating of foamed metal. Isochoric heating can be achieved by surrounding the foamed metal with a rigid-walled sapphire capillary. We evaluate the temperature and electrical conductivity of the foam∕plasma based on the line-pair method of the foam∕plasma emission and on the voltage-current waveforms. The electrical conductivity observed agrees with previous experiments and predictions. Thus, the proposed technique yields the electrical conductivity of warm dense matter with a well-defined temperature.     

Total fractional-order variation regularization based image reconstruction method for capacitively coupled electrical resistance tomography

Compared with electrical resistance tomography, capacitively coupled electrical resistance tomography (CCERT) is preferred since it avoids problems of electrode corrosion and electrode polarization. However, reconstruction of conductivity distribution is still a great challenge for CCERT. To improve reconstruction quality, this work proposes a novel image reconstruction method based on total fractional-order variation regularization. Simulation work is conducted and reconstruction of several typical models is studied. Robustness of the proposed method to noise is also conducted. Additionally, the performance of the proposed reconstruction method is quantitatively evaluated. We have also carried out phantom experiment to further verify the effectiveness of the proposed method. The results demonstrate that the quality of reconstruction has been largely improved when compared with the images reconstructed by Landweber, Newton-Raphson and Tikhonov methods. The inclusion is more accurately reconstructed and the background is much clearer even under the impact of noise.     

探头引线热损失对TPS法测量导热系数的影响

瞬态平面热源(Transient plane source,TPS)法是一种近年来发展起来的用于测量材料导热系数的方法.在测量过程中,加热功率受到探头引线传热的影响,进而会影响导热系数的测量准确度.针对这个问题,本文研究了测量过程中探头引线热损失对加热功率的影响,推导了热损失的数学计算公式,并提出了相应的修正模型.利用hot disk热常数分析仪对不同材料进行了一系列测量实验.实验结果表明引线热损失对测量的影响随着测量材料以及测试探头尺寸的不同而发生变化.当材料的导热系数大于0.2 W/(m·K)时,探头引线热损失的影响小于0.16％,可以忽略不计;但对于低导热系数材料的测量,对引线热损失进行补偿可以有效地提高导热系数的测量准确度.     

Magnetic induction tomography guided electrical capacitance tomography imaging with grounded conductors

Electrical capacitance tomography (ECT) is an imaging technique commonly used for imaging dielectric permittivity of insulating objects. In applications such industrial process tomography and non-destructive testing (NDT), the objects under test may exhibit variations in both dielectric permittivity and electrical conductivity. In particular, a sample that includes high conductivity, such as metal, can cause a large change in electrical field in ECT. The metal sample in imaging area will cause a large change in the sensitivity map of ECT compared to free space, which will make the ECT image reconstruction inaccurate. This effect is more severe in grounded conductor than floating conductors, so this paper focuses on grounded conductor. In order to update the sensitivity map, one needs to gain information about the conductivity distribution in ECT problem. Magnetic induction tomography (MIT) is sensitive to electrical conductivity and not sensitive to permittivity variations; therefore, it can be used to visualize the conductivity distribution of the target under test. In this paper, a dual-modality MIT and ECT system is proposed to image a medium including conductors and dielectrics. Both simulated and experimental results are presented, which demonstrate the feasibility of the proposed method.     

Development of electrically conductive hybrid nanofibers based on CNT‐polyurethane nanocomposite for cardiac tissue engineering

Conductive nanofibers have been considered as one of the most interesting and promising candidate scaffolds for cardiac patch applications with capability to improve cell–cell communication. Here, we successfully fabricated electroconductive nanofibrous patches by simultaneous electrospray of multiwalled carbon nanotubes (MWCNTs) on polyurethane nanofibers. A series of CNT/PU nanocomposites with different weight ratios (2:10, 3:10, and 6:10wt%) were obtained. Scanning electron microscopy, conductivity analysis, water contact angle measurements, and tensile tests were used to characterize the scaffolds. FESEM showed that CNTs were adhered on PU nanofibers and created an interconnected web‐like structures. The SEM images also revealed that the diameters of nanofibers were decreased by increasing CNTs. The electrical conductivity, tensile strength, Young's modulus, and hydrophilicity of CNT/PU nanocomposites also enhanced after adding CNTs. The scaffolds revealed suitable cytocompatibility for H9c2 cells and human umbilical vein endothelial cells (HUVECs). This study indicated that simultaneous electrospinning and electrospray can be used to fabricate conductive CNT/PUnanofibers, resulting in better cytocompatibility and improved interactions between the scaffold and cardiomyoblasts.     

The measurement of thermal conductivity variation with temperature for solid materials

An apparatus was designed to routinely measure the thermal conductivity variation with temperature for solid materials. The apparatus was calibrated by measuring the thermal conductivity variations with temperature for aluminum, zinc, tin and indium metals. The variations of thermal conductivity with temperature for the Zn-[x] wt.% Sb alloys (x = 10, 20, 30 and 40) were then measured by using the linear heat flow apparatus designed in present work. From experimental results it can be concluded that the linear heat flow apparatus can be used to measure thermal conductivity variation with temperature for multi component metallic alloys as well as pure metallic materials and for any kind of alloys. Variations of electrical conductivity with temperature for the Zn-[x] wt.% Sb alloys were determined from the Wiedemann–Franz (W–F) equation by using the measured values of thermal conductivity. Dependencies of the thermal and electrical conductivities on composition of Sb in the Zn–Sb alloys were also investigated. According to present experimental results, the thermal conductivity and electrical conductivity for the Zn-[x] wt.% Sb alloys decrease with increasing the temperature and the composition of Sb.     

Measurement of Electromagnetic Parameters of Metal-Coating Thickness Measures

Thickness measures for electrically conductive coatings applied to electrically conductive bases are described, for which not only geometrical but also electrophysical parameters such as the specific electrical conductivity and complex relative permeability of the measure base and the specific electrical conductivity of the measure coating are prescribed. The procedure and a technique for measuring the specific electrical conductivity of the base of a measure using the van der Pauw method, the complex relative magnetic permeability of metal on ring-shaped samples using a permeameter, a technique for transferring the value of this parameter to the measure base of an arbitrary shape with a flat surface, and also the procedure and a method for measuring the specific electrical conductivity of the coating-measure material with the use of an eddy current probe with a wave-like drive winding are described.     

VE-26NP Eddy-Current Structuroscope

The destination and technical characteristics of a VE-26NP eddy-current structuroscope are described. The domains of application and characteristics of the VE-26NP eddy-current structuroscope are presented. The question of the necessity for presorting on the basis of the specific electrical conductivity is considered. The possibilities of using the VE-26NP eddy-current structuroscope for nondestructive testing of the quality of heat treatment of products from nonmagnetic alloys are analyzed. Examples of testing the specific electrical conductivity of thin-wall objects are given.