Modern Testing Technology Research Articles

Research on vertical vibration characteristics of rolling mill based on magnetorheological fluid damper absorber

The study of rolling mill vibration theory has always been a scientific frontier in the field of rolling forming, which is very important to the quality of sheet metal and the stable operation of equipment. A magnetorheological fluid damper absorber is designed to control the nonlinear vertical vibration of rolling mill. Considering the fractional order and delay factors in the control effect of magnetorheological fluid, the fractional order delay nonlinear vertical vibration equation with magnetorheological damping damper is established. The amplitude-frequency characteristic equations of the main resonance and sub-resonance of the system are solved by multi-scale method. The effects of stiffness coefficient, damping coefficient, time delay, fractional order, and exciting force on the vibration characteristics of roller system are analyzed by comparing the amplitude-frequency curve, time-domain curve and phase diagram. The transition set of the steady-state response of the system and the corresponding bifurcation topology structure are analyzed by using the singularity theory. A magnetorheological fluid damper absorber platform of rolling mill is built based on modern test technology, and the influence laws of the control threshold, control current, type of magnetorheological fluid and reduction rate are analyzed. The correctness and feasibility of the design of the magnetorheological fluid damper absorber are verified, which provided theoretical guidance and technical support for the nonlinear dynamic analysis and stability control of the rolling mill.

Digital Case Database Construction and Case Teaching for the Course of Modern Testing Technology of Materials

The course of modern testing technology of materials has the properties of strong comprehensive nature and practical characteristic. Case database construction and case teaching play significant roles in enhancing the teaching quality and effects of the course for teachers and students. Based on the methods and techniques for measuring materials, this course designs basic theoretical cases, enterprise production cases, laboratory ability verification project cases and cutting-edge cases of joint use technology, and introduces them into the classroom for implementation, and the related cases are collected to build the digital case database. On the one hand, based on the digital case database, the implementation of case teaching of this course overcomes the difficulty that the teaching content is relatively independent and the students are difficult to compare and analyze the similar methods and techniques for measuring materials, making the students’ theoretical foundation more solid. On the other hand, based on the digital case database, the case teaching makes a comprehensive analysis of practical problems in production practice, stimulates students’ creativity and interest, and encourages students to provide solutions for the development or improvement of testing means, thus improving the quality of courses and the effectiveness of education. According to the survey, more students were satisfied with case teaching for the course of modern testing technology of materials and their test scores had been significantly improved. Furthermore, the digital case database broaden the channels and ways for students to study the course, and help students realize the new learning mode of learning at any time, flexible learning and long-term learning.

Multielectron Electrode Reaction Kinetics with RDE and RRDE: An Advanced Electrochemical Laboratory Experiment

Oxygen reduction reaction (ORR), as a multielectron electrode reaction, is an important electrochemical reaction in the field of electrochemical energy storage systems. Herein, a new advanced electrochemical laboratory experiment is designed for undergraduates to master the preparation of oxygen reduction catalytic electrode. Students can use rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) to evaluate the properties of the ORR catalyst and expound the kinetics mechanism of multielectron electrode reaction. By fitting the K–L curve to calculate the electron transfer number, the ORR reaction path of the industrial Pt/C catalyst in the KOH electrolyte can be determined. The basic kinetic parameters of the ORR and the intermediate content will help students to deeply understand the Butler–Volmer equation. The new teaching experiment focuses on the integration of frontier scientific research and undergraduate teaching. This experiment may enhance students’ interest in learning electrochemistry and broadening their horizons as well as help them understand the ORR mechanism involved in modern electrochemical testing technology. In addition, the student’s ability of data processing and comprehensive analysis will be improved. This new comprehensive experiment is a fundamental, innovative, and systematic physical chemistry experiment.

Средства и методы контроля знаний студентов в цифровой образовательной среде вуза при изучении инженерно-графических дисциплин

The paper deals with the problem of the precise assessment of university students’ knowledge when studying engineering and graphic disciplines in the digital learning environment. It is relevant to Russian higher education system oriented to modern testing technology that helps provide high-quality educational monitoring and fairly and accurately assess the level of students’ knowledge development. The benefit of systematic knowledge monitoring with the use of digital technology lies in its objectivity caused by the shift of emphasis to the informative function. In such a situation, the student will not be afraid of control and will not invent ways to get a higher grade, and the teacher will have a true idea of students’ knowledge and its compliance with the stated competencies. The paper provides a case study for decomposing a part of the subject area aimed at identifying the concepts that are necessary to draw up the tasks to assess and monitor the knowledge of the subject. The research presents the author’s view on this issue.

The Design of High Speed Acquisition and Storage System Based on Labview

The design of high speed data acquisition and storage system is based on Labview. It can not only achieve high accuracy and high data rate but also use the software and hardware synchronization trigger to complete the multi-channel continuous real-time monitoring of the acquisition and storage periodic signal. Which is similar to the function of the oscilloscope. This system is based on high speed data acquisition card of NI company and Labview 2012 for PC software development platform. Data acquisition card is used to finish data acquisition of periodic signal through the serial port. It also collect data upload to upper computer. Upper computer collect data for storage display and analysis to realize the real-time monitor of multi-channel analog. The design of the sampling channel is 2, the sampling rate up to 200M/s, the sampling precision is 12 bits, and the sampling depth is 2000. Lots of verification prove that the design has good compatibility, performance and stability of the collection. Data error is negligible by analyzing the data collected. More importantly, the design can be as far as possible to restore the actual signal source data without distortion. This paper provides a portable design for high speed data acquisition, which can be widely applied in the engineering of modern test and measurement technology.

基于Labview的高速数据采集与存储系统的设计

针对市面上现有的一般的数据采集卡采样位数不高和采样内存不够，从而不能进行长时间对信号进行有效的连续采样等问题。本文设计了基于labview的高速数据采集和存储系统。该系统能够实现高精度、高数据率，还可以采用软件和硬件同步触发的方式来完成对周期信号进行多通道连续实时监测采集和存储，使数据采集存储系统的采样内存扩展至电脑的内存。本系统以NI公司的高速数据采集卡为基础，以labview 2012为上位机软件开发平台，由数据采集卡对周期信号进行数据采集再通过串口将采集到的数据上传到上位机，上位机对采集的数据进行存储、显示和分析实现了多通道模拟量的实时监测。该设计最终实现了采样通道数为2，采样速率为200 M/s，采样精度为12位，采样深度达到2000。平台有效性验证了该采集平台兼容性好、性能稳定采集信号误差小，能够尽量做到对实际信号源数据的无失真还原。本文为高速数据采集提供了一种便携的设计方案，可以广泛的应用到现代测试测量技术工程中。 In view of the existing general data acquisition card in the market, it is not enough to have high sampling and sampling memory, so that the acquisition system cannot be carried out for a long time. The design of high speed data acquisition and storage system is based on Labview. It can not only achieve high accuracy and high data rate but also use the software and hardware synchronization trigger to complete the multi-channel continuous real-time monitoring of the acquisition and storage of periodic signal which is similar to the function of the oscilloscope. This system is based on high speed data acquisition card of NI company and Labview 2012 for PC software development platform. Data acquisition card is used for data acquisition of periodic signal through the serial port and collect data upload to upper computer. Upper computer collects data for storage, display and analysis to realize the real-time monitoring of mul-ti-channel analog. The design of the sampling channel is 2, the sampling rate up to 200 M/s, the sampling precision is 12, and the sampling depth is 2000. Platform validation of the collection platform has good compatibility, performance and stability of the collection signal error is ignorable, which can be as far as possible to the actual signal source data without distortion reduction. This paper provides a portable design for high speed data acquisition, which can be widely used in the engineering of modern test and measurement technology.

Preparation and Performance of β-Sialon/Si<sub>3</sub>N<sub>4</sub> Composite Ceramics for Solar Heat Absorber

β-Sialon/Si3N4composite ceramic were prepared from starting materials of α-Si3N4, AlN and Al2O3by pressureless sintering. The physical properties, phase composition and microstructure were tested by modern testing technology. The effect of different additives such as Y2O3, La2O3and borax on the sintering temperature and physical properties was studied. The results show that D3 is the best formula, firing shrinkage rate of the sample is 14.14%, water absorption 3.16%, porosity 9.02%, bulk density 2.85g·cm-3and bending strength 193.87MPa after firing at 1580°C. XRD analysis indicates that the main phases of D3 are β-Sialon, β-Si3N4and corundum. SEM analysis shows that the microstructure of D3 sample is quite dense and the pores distribution is uniform, the diameter of the pore is about 1~5μm. β-Sialon/Si3N4composite ceramic has high bulk density, bending strength and fine microstructure, which is a new choice of the heat absorb material for solar thermal power generation system.

Research and Application of S-4800 Scanning Electron Microscope in Modern Testing and Analysis Technology

Mechanism and functions of S-4800 Scanning Electron Microscope are introduced in this paper. The image-forming mechanism and structure of SEM are studied, and the signal transformation of secondary electron and backscattered electron is presented. The main application fields of SEM are researched.

The Monitoring and Fault Diagnosis System for Controllable Pitch Propeller Based on LabVIEW

The monitoring and fault diagnosis system for controllable pitch propeller is based on modern testing technology, fieldbus technology, monitoring and diagnosis technology, computer technology. The equipment consists of various types of sensors, CANopen bus devices, LabVIEW and computer, which can monitor the CPP’s operating parameters, including shaft system vibration, shaft speed, pitch angle, liquid level of gravity tank, pressure and temperature of hydraulic system, and the system can also alarm if three typical fault of shafting occurs.

Non-Intrusive Magneto-Optic Detecting System for Investigations of Air Switching Arcs

In current investigations of electric arc plasmas, experiments based on modern testing technology play an important role. To enrich the testing methods and contribute to the understanding and grasping of the inherent mechanism of air switching arcs, in this paper, a non-intrusive detecting system is described that combines the magneto-optic imaging (MOI) technique with the solution to inverse electromagnetic problems. The detecting system works in a sequence of main steps as follows: MOI of the variation of the arc flux density over a plane, magnetic field information extracted from the magneto-optic (MO) images, arc current density distribution and spatial pattern reconstruction by inverting the resulting field data. Correspondingly, in the system, an MOI set-up is designed based on the Faraday effect and the polarization properties of light, and an intelligent inversion algorithm is proposed that involves simulated annealing (SA). Experiments were carried out for high current (2 kA RMS) discharge cases in a typical low-voltage switchgear. The results show that the MO detection system possesses the advantages of visualization, high resolution and response, and electrical insulation, which provides a novel diagnostics tool for further studies of the arc.

Teaching Innovation and Exploration of Principles and Applications of Transducer Course Based on CDIO Idea

The course teaching pattern reform is conducted in order to solve the problems existing in the teaching progress of principles and applications of transducer course for measurement & control technology and instrument specialty. According to the teaching idea of CDIO, the project item teaching method is introduced in course teaching. Theoretical and practical teaching schemes are designed and the teaching process and evaluation mode are optimized then. After the exploratory research of theory and practice teaching, a set of course teaching system for principles and applications of transducer course is formed based on the concept of CDIO. Curriculum reformation combines classical measure theory with modern test technology properly as well as considers its theory and application, remarkable teaching effect is obtained then. It provides a new teaching method suitable for principles and applications of transducer course.

Research on a New Circuit of Temperature Measurement

Temperature measurement is an important link in industrial production, also an important part of modern testing technology. The traditional single bridge circuit is already unable to meet the requirements of modern precise temperature measurement system on temperature measurement. The relation between the output voltage of general Wheatstone bridge and real strain is nonlinear. The nonlinear error will be very serious if the variance ratio of resistance ΔR/ R is very large. Platinum resistance temperature sensor as temperature element may also cause nonlinear error.And measuring ranges small for bridge. This paper designs RC filter circuit and second-order band-pass filter circuit as the core of a new type of temperature measurement circuit ,introduces the principle of temperature measurement and the generation of signal source .Circuit cooperates with thermistor sensor, not only realizes the high precise temperature measurement, but also solves the measurement error of sensor produced from heating. Experiment checks that measuring precision can satisfy measurement requirements. DOI: http://dx.doi.org/10.11591/telkomnika.v11i8.3105

Preparation and electrical-magnetic properties of Co0.6Cu0.16Ni0.24Fe2O4/MWCNTs composites

Co0.6Cu0.16Ni0.24Fe2O4/multi-walled carbon nanotube nanocomposites (CCNF/MWCNTs) were synthesized by solution filling method. The phase structure, thermal stability, morphology and electrical-magnetic properties of the samples were characterized by means of modern testing technology. The effect of iron concentration, filling time, sintering temperature on their electrical and magnetic performance was discussed. The results indicated that conductivity was related to the content of MWCNTs, while the magnetism correlated with the volume fraction of the filled CCNF in the composites. When the optimal condition satisfied the filling time of 18 h, ferric concentration of 0.25 mol L−1 and sintering temperature of 350°C, the prepared composite had the best magnetic loss performance, and its minimum reflection loss reached −22.47 dB on 9.76 GHz, the available bandwidth was beyond 2.0 GHz. Hence, the obtained composite can be used as advancing absorption and shielding material due to its favorable microwave absorbing property.

Three-Dimensional Micro-Displacement Control System for a Conductor Defect Detection System

This paper proposes a method to detect conductor defects in the field of modern non-destructive testing technology. A self-magnetic field induced by flowing current in the conductor is used in the detection technique, and a three-dimensional micro-displacement stage platform is used to scan the sample surface to obtain the self-magnetic field mapping of the whole sample. The subsequent data processing and imaging technology of the detection signal is also developed. To achieve precise positioning of the triaxial directions, an STM32 microcontroller (MCU) is used as the central processor to design the displacement control system, which communicates with a PC computer through the MCU system. The experimental results demonstrate that the stepper motor driving the magnetic sensor could run uniformly and that the proposed system has the advantages of smooth motion, low noise and high precision. As a consequence, the micro-displacement control system can be used to get a clear mapping of the defects in the sample.

Static Strength Test and Analysis of the Hot-Metal Car Frame

260T hot-metal car is a huge shape machinery product used in iron and steel plant for the short distance transportation. The work conditions of the hot-metal car are bad, so the reliability of the product structure must be guaranteed. During the structure design, theoretical study and computer simulation analysis of the car frame are taken using the commercial finite element software. The tests for the 260T hot-metal car product are accomplished by using the modern static testing technology to verify the theoretical calculation. The paper describes the test scheme and field test process, extracts the strain and stress value of key points on the car frame and analyses the test data. At last, the test result data are compared with the finite element computation result data, verifying the theoretical calculation.

Teaching Innovation and Exploration of College Electronic Measurement Technology Course

In this paper, the course content of electronic measurement technology is introduced from subject perspective. Some problems existing in theory and practice teaching are analyzed in detail. According to the current situation of curriculum teaching in our university, innovation and exploration is carried out and some reform measures are put forward based on existing methods. Finally, the improvement on the forms and contents of course assessment is envisaged. Curriculum reformation combines classical measure theory with modern test technology properly as well as considers its theory and application, remarkable teaching effect is obtained then. It provides a new teaching method suitable for electronic measurement technology course.

Visualization Experiment with PIV and Analysis of Flow Field in Hydrodynamic Coupling

In order to study the complex flow state of the internal flow field while the hydrodynamic coupling is under working conditions, the two dimensions PIV technique of the modern testing technology is adopted to test and analyze typical working conditions of hydrodynamic coupling. According to the experimental results, the internal flow field of the typical working conditions is analyzed and compared in qualitative way. The research of this paper has guiding significance for the hydrodynamic coupling design.

Diagnostic performance in a primary referral hospital assessed by autopsy: Evolution over a ten-year period

Background Despite remarkable progress in modern laboratory testing and imaging technology in recent years, diagnostic errors still occur. To assess whether diagnostic performance in a primary referral hospital improves with new diagnostic tools and algorithms, autopsy reports were analyzed over a ten-year period to monitor diagnostic errors. Methods Medical reports from 1997 to 2006 were compared retrospectively with autopsy reports. A diagnostic error was assumed when the main clinical diagnosis was missed, independently of whether this influenced the patient's survival or whether this error led to incorrect treatment without effect on survival. Two cardiovascular markers with high sensitivity, namely cardiac troponin T and D-dimer testing and two algorithms for thoracic pain and thromboembolic disease were introduced during the study period. Results 970 cases were included; the autopsy rate was 50.1%. Cardiovascular diseases were misdiagnosed in 18.7%, followed by infectious diseases in 12.9%, oncological 3.6% and neurological diseases in 1.8%. The most commonly missed diagnoses were myocardial infarction, pulmonary embolism and aortic dissection; however, the rate of errors for cardiovascular diseases decreased over the 10 years ( p < 0.002). Overall diagnostic sensitivity and specificity rose from 67% to 87% and from 94% to 99%, respectively. Conclusion Autopsy remains a valuable tool to measure diagnostic performance. Errors occur most frequently in cardiovascular events, whereas in malignant and neurological diseases they are rare. The significant improvement of diagnostic accuracy for cardiovascular diseases is associated with the introduction of new sensitive laboratory tests and algorithms for thoracic pain and thromboembolic diseases.

Guest editors' introduction: stressing the fundamentals

Presents the guest editorial for this issue of the publication.

Sexuality and health challenges: Responding to a public health imperative

Sexuality is associated with a number of public health imperatives to prevent disease or disability or, if prevention is not possible, to treat and reduce the burden of disease as expeditiously as possible. With the advent of modern testing technology and better sampling of populations, the burden of sexually transmissible infections, sexual assault, and sexual disability have become more apparent. Presented here are U.S. data on the public health dimensions of human sexuality and the evidence for the urgent need to address the magnitude of sexually related public health problems.