Analysis of Standards Establishment for the Testing of Electrical Appliances

As science and technology continue to develop,power equipment has become an indispensable part of industrial production and daily life.Whether it is the precise automation machinery utilized on production lines or the convenient electrical appliances found in households,their functionality relies heavily on electrical technology.Nonetheless,without stringent safety and performance assurances,these devices could potentially endanger lives and property.Thus,this paper explores the development strategy for establishing a standardized system within the electrical testing service industry,aiming to ensure safety and reliability.

Obtaining 2D Soil Resistance Profiles from the Integration of Electrical Resistivity Data and Standard Penetration Test (SPT) and Light Dynamic Penetrometer (DPL) Resistance Tests—Applications in Mass Movements Studies

In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occurrences. The multifaceted nature of these influences makes the surveillance of mass movements a highly intricate task, requiring an understanding of numerous interdependent variables. Recent years have seen an emergence in scholarly research aimed at integrating geophysical and geotechnical methodologies. The conjoint examination of geophysical and geotechnical data offers an enhanced perspective into subsurface structures. Within this work, a methodology is proposed for the synchronous analysis of electrical resistivity geophysical data and geotechnical data, specifically those extracted from the Light Dynamic Penetrometer (DPL) and Standard Penetration Test (SPT). This study involved a linear fitting process to correlate resistivity with N10/SPT N-values from DPL/SPT soundings, culminating in a 2D profile of N10/SPT N-values predicated on electrical profiles. The findings of this research furnish invaluable insights into slope stability by allowing for a two-dimensional representation of penetration resistance properties. Through the synthesis of geophysical and geotechnical data, this project aims to augment the comprehension of subsurface conditions, with potential implications for refining landslide risk evaluations. This endeavor offers insight into the formulation of more effective and precise slope management protocols and disaster prevention strategies.

Accelerated Degradation Reliability Modeling and Test Data Statistical Analysis of Aerospace Electrical Connector

As few or no failures occur during accelerated life test,it is difficult to assess reliability for long-life products with traditional life tests.Reliability assessment using degradation data of product performance over time becomes a significant approach.Aerospace electrical connector is researched in this paper.Through the analysis of failure mechanism,the performance degradation law is obtained and the statistical model for degradation failure is set up; according to the research on statistical analysis methods for degradation data,accelerated life test theory and method for aerospace electrical connector based on performance degradation is proposed by improving time series analysis method,and the storage reliability is assessed for Y11X series of aerospace electrical connector with degradation data from accelerated degradation test.The result obtained is basically consistent with that obtained from accelerated life test based on failure data,and the two estimates of product＇s characteristic life only have a difference of 8.7%,but the test time shortens about a half.As a result,a systemic approach is proposed for reliability assessment of highly reliable and long-life aerospace product.

Analysis and Applications of the Measurement Uncertainty in Electrical Testing

Recently, uncertainty measurement is more and more recognizable in modern data management, conformity assessment, and laboratory accreditation system because of its importance. In this paper, a set of reasonable probability explanations are introduced and an effective method is pro- posed to quantify the assessment indices for the uncertainty measurement of electrical testing laboratory. First of all, the influence from uncertainty factors during the test process is taken into account. With the use of ISO/IEC Guide 98-3 standard and probability theory, the index and model for the measurement uncertainty assessment of a laboratory is then derived. From the simulation results of safety testing, laboratory uncertainty measurement assessment activity for actual electrical appliances, and the confirmation of Monte Carlo simulation method, the appropriateness and correctness of proposed method are verified.

Non-destructive experimental testing and modeling of electrical impedance behavior of untreated and treated ultra-soft clayey soils

The characterization of ultra-soft clayey soil exhibits extreme challenges due to low shear strength of such material.Hence,inspecting the non-destructive electrical impedance behavior of untreated and treated ultra-soft clayey soils gains more attention.Both shear strength and electrical impedance were measured experimentally for both untreated and treated ultra-soft clayey soils.The shear strength of untreated ultra-soft clayey soil reached 0.17 kPa for 10% bentonite content,while the shear strengths increased to 0.27 kPa and 6.7 kPa for 10% bentonite content treated with 2% lime and 10% polymer,respectively.The electrical impedance of the ultra-soft clayey soil has shown a significant decrease from 1.6 kΩ to 0.607 kΩ when the bentonite content increased from 2% to 10% at a frequency of 300 kHz.The10%lime and 10% polymer treatments have decreased the electrical impedances of ultra-soft clayey soil with 10%bentonite from 0.607 kΩ to 0.12 kΩ and 0.176 kΩ,respectively,at a frequency of 300 kHz.A new mathematical model has been accordingly proposed to model the non-destructive electrical impedancefrequency relationship for both untreated and treated ultra-soft clayey soils.The new model has shown a good agreement with experimental data with coefficient of determination（R;）up to 0.99 and root mean square error（RMSE） of 0.007 kΩ.

Quality Evaluation of Diffusion Bonded Joints by Electrical Resistance Measuring and Microscopic Fatigue Testing

Micro-structure related behavior of diffusion bonding joints is a crucial issue in device and reactor fabrication of Micro Chemo Mechanical Systems.However,the previous studies have been focused on the macro mechanical performance of diffusion bonded joint,especially diffusion bonding conditions effects on tensile strength,shearing strength and fatigue strength.The research of interfacial micro-voids and microstructures evolution for failure mechanism has not been carried out for diffusion-bonded joints.An interfacial electrical resistance measuring method is proposed to evaluate the quality of bonded joints and verified by using two-dimensional finite-element simulation.The influences of micro void geometry on increments of resistance are analyzed and the relationship between bonded area fraction and resistance increment is established by theoretical analysis combined with simulated results.Metallographic inspections and micro-hardness testing are conducted near the interface of diffusion bonded joints.For the purpose of identifying the failure mechanisms of the joints,both microscopic tensile and fatigue tests are conducted on the self-developed in-situ microscopic fatigue testing system.Based on the microscopic observations,the mechanism of interfacial failure is addressed.The observation result shows that for 316LSS diffusion-bonded joints,microstructure evolution and effect of micro-voids play a key role in interfacial failure mechanism.Finally,a new life prediction model in terms of the increment of electrical resistance is developed and confirmed by the experimental results.The proposed study is initiated that constituted a primary interfacial failure mechanism on micron scale and provide the life prediction for reliability of components sealed by diffusion bonding.

Electrical Emissions from Concrete under Three-point Bending Tests

Electrical emission (EM) signals, which are generated from the concrete specimens under three-point bending tests, were conducted. It is shown that electrical emission phenomena are related to cracking of the specimens, cohesive failure, contact-separation etc. The simultaneous appearance of electric emission signals and visible cracks during the flexure loading of beams was also observed.

Nondestructive Testing Electrical Methods for Sensing Damages in Cement Mortar Beams

This paper discusses the experimental results of concurrently measured Electrical and Acoustic Emissions in order to evaluate the mechanical health status of cement mortar beams subjected to three-point bending mechanical tests. In particular, the Electrical Resistance and the Electrical Current emissions are recorded concurrent with Acoustic Emissions and the experimental results are discussed under the concept of crack initiation and propagation processes. For the first time, the electrodes that are used for conducting the measurements are placed in the bulk of the specimen, near the tensile zone, during its preparation. The damage evolution is examined by monitoring the fractional change of the Electrical Resistance and the variation of the Electrical Current in combination with the Acoustic Emission recordings.

An Electrical Impedance Imaging System Towards Edge Intelligence for Non-Destructive Testing of Concrete

In the construction industry,to prevent accidents,non-destructive tests are necessary and cost-effective.Electrical impedance tomography is a new technology in non-invasive imaging in which the image of the inner part of conductive bodies is reconstructed by the arrays of external electrodes that are connected on the periphery of the object.The equipment is cheap,fast,and edge compatible.In this imaging method,the image of electrical conductivity distribution(or its opposite;electrical impedance)of the internal parts of the target object is reconstructed.The image reconstruction process is performed by injecting a precise electric current to the peripheral boundaries of the object,measuring the peripheral voltages induced from it and processing the collected data.In an electrical impedance tomography system,the voltages measured in the peripheral boundaries have a non-linear equation with the electrical conductivity distribution.This paper presents a cheap Electrical Impedance Tomography(EIT)instrument for detecting impurities in the concrete.A voltage-controlled current source,a micro-controller,a set of multiplexers,a set of electrodes,and a personal computer constitute the structure of the system.The conducted tests on concrete with impurities show that the designed EIT system can reveal impurities with a good accuracy in a reasonable time.

Oxidation Modification of Polyacrylonitrile-Based Carbon Fiber and Its Electro-Chemical Performance as Marine Electrode for Electric Field Test

A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^(1/2)@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.

Experimental and analytical studies on multiple tuned mass dampers for seismic protection of porcelain electrical equipment

Porcelain electrical equipment （PEE）, such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers （MTMD）. An MTMD damping device involving three mass units, named a triple tuned mass damper （TTMD）, is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.

Early electrical field stimulation prevents the loss of spinal cord anterior horn motoneurons and muscle atrophy following spinal cord injury

Our previous study revealed that early application of electrical field stimulation（EFS） with the anode at the lesion and the cathode distal to the lesion reduced injury potential, inhibited secondary injury and was neuroprotective in the dorsal corticospinal tract after spinal cord injury（SCI）. The objective of this study was to further evaluate the effect of EFS on protection of anterior horn motoneurons and their target musculature after SCI and its mechanism. Rats were randomized into three equal groups. The EFS group received EFS for 30 minutes immediately after injury at T_（10）. SCI group rats were only subjected to SCI and sham group rats were only subjected to laminectomy. Luxol fast blue staining demonstrated that spinal cord tissue in the injury center was better protected; cross-sectional area and perimeter of injured tissue were significantly smaller in the EFS group than in the SCI group. Immunofluorescence and transmission electron microscopy showed that the number of spinal cord anterior horn motoneurons was greater and the number of abnormal neurons reduced in the EFS group compared with the SCI group. Wet weight and cross-sectional area of vastus lateralis muscles were smaller in the SCI group to in the sham group. However, EFS improved muscle atrophy and behavioral examination showed that EFS significantly increased the angle in the inclined plane test and Tarlov＇s motor grading score. The above results confirm that early EFS can effectively impede spinal cord anterior horn motoneuron loss, promote motor function recovery and reduce muscle atrophy in rats after SCI.

The Electrical Properties and Snow Melting of Graphite Slurry Infiltrated Steel Fiber Concrete

The conductivity property of graphite slurry infiltrated steel fiber concrete （GSIFCON） was investigated by the four-probe method. The experimental results show that the electrical resistivity of GSIFCON decreases significantly at a specific concentration of graphite, i e, the percolation concentration. A model was accordingly developed to explain its conductive mechanism, where graphite particles could be served as bridge for conductive network between unconnected fiber chains. For an application, snow melting test of GSIFCON was carried out and a simple heating power analysis was performed. The results reveal that the thermal energy produced by GSIFCON makes snow melting effectively and the electrothermal efficiency can reach approximately 20%.

Electrical crosstalk-coupling measurement and analysis for digital closed loop fibre optic gyro

The phase modulation and the closed-loop controller can generate electrical crosstalk-coupling in digital closed- loop fibre optic gyro. Four electrical cross-coupling paths are verified by the open-loop testing approach. It is found the variation of ramp amplitude will lead to the alternation of gyro bias. The amplitude and the phase parameters of the electrical crosstalk signal are measured by lock-in amplifier, and the variation of gyro bias is confirmed to be caused by the alternation of phase according to the amplitude of the ramp. A digital closed-loop fibre optic gyro electrical crosstalk-coupling model is built by approximating the electrical cross-coupling paths as a proportion and integration segment. The results of simulation and experiment show that the modulation signal electrical crosstalk-coupling can cause the dead zone of the gyro when a small angular velocity is inputted, and it could also lead to a periodic vibration of the bias error of the gyro when a large angular velocity is inputted.

Implementation of Dynamic System Control Circuit Board Test System of Pure Electric Vehicles

The dynamic system control circuit board(DSCCB)is one of the most important components for dynamic system of pure electric vehicles. The current detection of the DSCCB is done manually, which is not only inefficient in the detection but also difficult to guarantee the data accuracy. In order to improve the detection efficiency and accuracy, a new testing system is designed by Labview. The total test time can be further reduced by about 75% compared with the results of the manual detection. In this paper, the three-parameter sine wave curve-fit algorithm theory is applied to the phase delay detection of the current sensor sampling circuit on the DSCCB. This method solves the problem of big error in the phase delay detection.

Electrical Resistance Change of Carbon/Epoxy Composite Laminates under Cyclic Loading under Damage Initiation Limit

Self-sensing multifunctional composite has sensing function using electrical resistance changes. Carbon Fiber Reinforced Polymer (CFRP) composite is one of the self-sensing multifunctional composites. For the reliability of the self-sensing, electrical contact between the lead wire and the carbon fibers is the most important issue. The present study focuses on the effect of the cyclic loading of lower applied strain range than the fatigue damage level. As a result, the electrical contact resistance at the copper electrode increased with the increase of cycles. That means that the electrical change at the electrodes must be considered for the long-term self-sensing monitoring system. When a four-probe method is used to measure the electrical resistance, the contact resistance effect is minimized. Moreover, angle-ply laminates have plastic deformation caused by shear loading, and that causes electrical resistance decrease during the cyclic loading. Cross-ply laminates of CFRP composites have no electrical resistance increase without damage. Quasi-isotropic laminates of CFRP composites, however, have electrical resistance decrease with the increase of the number of cycles because of the plastic deformation of the angle-ply laminates.

Comparison between the electrical resistance and the shear strength of brazed cemented carbides

Brazing is a suitable technology to join different materials such as cemented carbides and steel. Even though this technology has been investigated for many years, insufficient joints can occur easily, as the brazing process is very sensitive concerning the handling parameters. Defects such as voids and cracks are hard to detect by commonly used visual inspection methods. Other nondestructive methods such as radiography or ultrasonic testing are usually not economical for the examination of these joints. Studies proved that the electrical resistance has the potential to serve as an effective alternative for the evaluation of brazed joints. In this study, the authors have compared the electrical resistance and the shear strength. For this, cemented carbides were brazed to steel by means of induction heating at an ambient atmosphere. A silver-based filler metal （ BrazeTec 4900 / Ag 449 ） and a flux （ BrazeTec spezial h / FH12） were selected to enable the brazing process. The brazing time and the temperature were varied in order to produce different joint qualities. After brazing, the resistance was measured on each joint with the 4-point probe method to facilitate a high accuracy. The results underline the possibility to use electrical resistance measurements as an effective tool for a quality control of brazed joints.

A model-based driving cycle test procedure of electric vehicle batteries

The battery test methods are the key issues to investigate the energy-storage characteristics and dynamic characteristics of electric vehicle(EV) batteries.In this paper,the research advances of existing battery test methods as well as driving cycles are reviewed.An electric vehicle model that consists of EV dynamics model,battery model and electric motor model is built.The dynamic characteristics of the battery in frequency domain are analyzed.Based on the EV model and the frequency domain characteristics of the battery,a driving cycle test procedure of EV battery is proposed.The battery test procedure is able to reflect the real-world characteristics of EV batteries,and can be used as a universal EV battery test method.

Clinical observation of acupoint injection combined with nerve electrical stimulation in the treatment of post-stroke dysphagia

Background:Post-stroke dysphagia is one of the common clinical symptoms in the rehabilitation department of primary hospitals,which seriously affects the quality of life of patients and their families.Majority of medical workers have comprehensively studied post-stroke dysphagia as it easily induces inhalation pneumonia,asphyxia,and many other complications.At present,many methods for post-stroke dysphagia have been proved to be effective.With regard to comprehensive treatment effect,patient compliance,technology promotion difficulty,grassroots hospital operability,and other factors,we found that acupoint injection combined with nerve electrical stimulation is a good method worthy of promotion.Methods:A total of 130 patients with dysphagia after stroke were randomly divided into nerve electrical stimulation group(n=41),acupoint injection group(n=40),and comprehensive treatment group(nerve electrical stimulation plus acupoint injection,n=49).The therapeutic effect in each group was evaluated before treatment and 20 days after treatment using the improved water swallow test,video fluoroscopic swallowing study,and standardized swallowing assessment.Results:After 20 days of treatment,significant differences were noted in each group.The scores of improved water swallow test decreased from 4.10±0.74 to 2.12±0.95 in the nerve electrical stimulation group,4.00±0.78 to 2.28±1.04 in the acupoint injection group,and 4.16±0.77 to 1.73±0.79 in the comprehensive treatment group;video fluoroscopic swallowing study scores increased from 3.71±2.16 to 5.05±2.111 in the nerve electrical stimulation group,3.80±1.94 to 5.20±1.942 in the acupoint injection group,and 3.73±2.22 to 6.24±2.21 in the comprehensive treatment group;and standardized swallowing assessment scores of the three groups also decreased from 35.13±3.38 to 28.17±3.42,34.66±3.46,and 34.48±3.26 to 26.39±3.86,respectively.The overall scores of each group after treatment were significantly different from those before treatment(P<0.05),indicating that both nerve electrical stimulation and acupoint injection were effective for post-stroke dysphagia;the scores of nerve electrical stimulation group and acupoint injection group were similar,but those of the comprehensive treatment group were significantly better than the single treatments(P<0.05).It shows that the two treatment methods have synergistic effect,and combined treatments have more benefits.Conclusion:Nerve electrical stimulation and acupoint injection have a synergistic therapeutic effect on post-stroke dysphagia.The combined treatment is more beneficial to patients with post-stroke dysphagia than the single treatments.

Mechanical and electrical properties of Pd-Ru system doped with Zr, Mo, Y

The effect of Zr, Mo, Y dopant on mechanical and electrical properties of Pd-Ru binary alloy was investigated in this work. The alloys were prepared in a vacuum high-frequency melting furnace. X-ray diffraction and metallographic microscope were employed to detect the microstructures of alloys. Electric bridge and eddy current conductive instrument were employed to test the electrical resistivity, and the mechanical properties of alloys were tested by AG-X100KN-type tensile testing machine. The results show that adding rare metal elements into Pd-Ru system could refine the structure effectively and increase the melting point, density, tensile strength, and hardness of alloy, but the elongation and electrical conductivity of alloy decrease. © The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2012.