Performance and Safety Improvement of Induction Motors based on Testing and Evaluation Standards

The induction motor,which converts electrical energy into mechanical energy,has been recognized as the cornerstone of industrialization.The rotor of an induction motor can be either a squirrel cage rotor or a wound-type rotor,both existing as magnetless topologies.Three-phase squirrel cage induction motors are frequently utilized in industrial drives because they are dependable,have high starting torque,are selfstarting and affordable.Single-phase induction motors,on the other hand,are commonly used for small loads such as domestic appliances in form of modest fans,pumps and electric power tools.In South Africa,there have been reports of fires and explosions resulting in live and property loss because of induction motors that have not been thoroughly tested or are incorrectly labelled in terms of ratings,electrical safety and performance.The goal of this study is targeted at preventing end-user injuries and failures caused by non-compliant induction motors,by evaluating locally manufactured/imported induction motors based on tests and evaluation from standards(IEC and SANS).The study is conducted using experimental procedures at the Explosion Prevention Technology and Rotating Machines(EPT and RM)laboratory,South African Bureau of Standards(SABS),South Africa.The main finding from the study shows differences in the nameplate characteristics of various induction motors which could have detrimental effects such as production and operational downtime in their end-use industries,at later stages.

Flexible pavement longitudinal joint quality evaluation using non-destructive testing

Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance.Current quality control(QC)and quality assurance(QA)plans provide limited coverage.Consequently,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation methods.It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics.The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality.The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint.The paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during construction.It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.

Acoustic Non-Destructive Testing Technology in Concrete Bridge Inspection and Pile Foundation Detection

This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection.It includes an overview of a certain bridge construction project studied and acoustic non-destructive testing technology and the application of acoustic non-destructive testing technology in actual testing.This analysis hopes to provide some guidelines for acoustic non-destructive testing of modern concrete bridge projects.

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.

Compressive Strength of Basic Magnesium Sulfate Cement Coral Aggregate Concrete(MCAC)on Non-Destructive Testing

Basic magnesium sulfate cement coral aggregate concrete(MCAC)is a new type of concrete consisting of basic magnesium sulfate cement,coarse coral aggregate,coral reef sand and seawater.The rebound hammer(RH),the ultrasonic pulse velocity(UPV)and the compressive strength(fcu)tests of 14 sets of cube specimens of the MCAC after 28 d of aging were conducted.The impact of the content and length of sisal fiber on the relationship between the fcu-RH and the fcu-UPV was determined.A mathematical model was established to predict the strength of the MCAC using the UPV,RH,and comprehensive UPV/RH methods and to obtain the curves of test strength.The applicability of the test strength curves of ordinary portland concrete(OPC),light-weight aggregate concrete(LAC),and coral aggregate concrete(CAC)to MCAC was assessed.The results showed that the test strength curves of OPC,LAC and CAC were inappropriate to determine the strength of MCAC using non-destructive method.The relative standard error of the curves of test strength of the RH method and the comprehensive method met the specifications,whereas that of the UPV method did not.

Discussion on the Status Quo of Non-Destructive Testing Technology in Highway Engineering and Strategies of Improving the Quality of Testing

Highway test and detection technology play a very important role in controlling the quality of road and bridge engineering and improving the maintenance of roads and bridges.The study of highway bridge test detection technology is both theoretically and practically useful.Road and bridge test and detection is a complicated task.With the development of science and technology,highway and bridge engineering test and detection technology has also made great progress.The continuous improvement of test and detection technology has brought good social benefits to road and bridge construction.This article discusses the problems in test and detection technology of highway bridges and how to improve the quality of test and detection.

Application of Non-Destructive Testing Technology in Quality Testing and Control of Water Conservancy Projects

In view of social development,the demand for water conservancy engineering applications continues to increase.The number and scale of water conservancy projects in China have been in a state of continuous expansion in recent years.As a result,how to achieve efficient testing and effective control of the quality of water conservancy projects has always been a topic of discussion in the field of water conservancy engineering in our country.This paper summarizes the application of non-destructive testing technology in the quality testing and control of water conservancy projects.On the basis of explaining the connotation and application advantages of non-destructive testing technology,the non-destructive testing application strategies for concrete strength,steel corrosion and shallow cracks in water conservancy projects were studied.

Micromechanical testing and property upscaling of planetary rocks:A critical review

Knowledge of the mechanical behavior of planetary rocks is indispensable for space explorations.The scarcity of pristine samples and the irregular shapes of planetary meteorites make it difficult to obtain representative samples for conventional macroscale rock mechanics experiments(macro-RMEs).This critical review discusses recent advances in microscale RMEs(micro-RMEs)techniques and the upscaling methods for extracting mechanical parameters.Methods of mineralogical and microstructural analyses,along with non-destructive mechanical techniques,have provided new opportunities for studying planetary rocks with unprecedented precision and capabilities.First,we summarize several mainstream methods for obtaining the mineralogy and microstructure of planetary rocks.Then,nondestructive micromechanical testing methods,nanoindentation and atomic force microscopy(AFM),are detailed reviewed,illustrating the principles,advantages,influencing factors,and available testing results from literature.Subsequently,several feasible upscaling methods that bridge the micro-measurements of meteorite pieces to the strength of the intact body are introduced.Finally,the potential applications of planetary rock mechanics research to guiding the design and execution of space missions are environed,ranging from sample return missions and planetary defense to extraterrestrial construction.These discussions are expected to broaden the understanding of the microscale mechanical properties of planetary rocks and their significant role in deep space exploration.

Phase aberration correction in ultrasonic phased array non-destructive testing systems

Phase aberration correction for medical ultrasound systems has attracted a great deal of attention. Since phased array techniques are now widely employed for industrial non-destructive testing （NDT） applications in various fields, the problem of phase aberrations in the process of NDT testing is considered. The technique of cross-covariance for phase aberration correction is presented. The performance of the technique for phase aberration correction is tested by means of echo signals obtained in practical non-destructive testing experiment. The results show that the technique has the better accuracy of phase correction.

Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge

The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively.

Pulsed Eddy Current Non-destructive Testing and Evaluation:A Review

Pulsed eddy current （PEC） non-destructive test- ing and evaluation （NDT＆E） has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the lit- erature covering both structural integrity inspection and material characterization in various industrial sectors. To support its development and for better understanding of the phenomena around the transient induced eddy currents, attempts for its modelling both analytically and numeri- cally have been made by researchers around the world. This review is an attempt to capture the state-of-the-art development and applications of PEC, especially in the last 15 years and it is not intended to be exhaustive. Future challenges and opportunities for PEC NDT＆E are also presented.

A coin-tap method of composite materials non-destructive testing based on improved grey clustering

Aiming at the problems of low reliability and complex operation of traditional coin-tap test of composite material,this paper introduces the grey system theory and achieves better performance.The response signals of coin-tap are classified through the grey clustering based on relation analysis,and corresponding improvements are made to the calculation method of the relation degree of nearness.First,the time history of acceleration is taken as the system behavior sequence.The improved correlation calculation method is used to solve the relation degree of nearness between the sequences,and the matrix of degree of grey relation is constructed based on this.Then,the sequence groups are summarized through the matrix,and the response signals of coin-tap are qualitatively classified according to the location of the reference sequence.Finally,the defect detection of composite materials is completed without pre-testing.The test results show that the accuracy of the coin-tap test based on improved grey clustering reaches 100%,which simplifies the operation steps while ensuring the reliability of the coin-tap test results.

Non-Destructive Testing of Structures Using Optical and Other Methods: A Review

Non-destructive testing (NDT) of structures is one of the most important tasksof the proper maintenance and diagnosis of machines and constructions structuralcondition. NDT methods contribute to the damage tolerance philosophy used in theaircraft design methodology as well as many other operation and maintenance programsof machinery and constructions. The following study is focusing on overviewing animportant group of NDT methods: the optical and other ones, which found broadapplicability in scientific and industrial studies nowadays. The paper discusses theselected most widely applicable methods, namely, visual testing, ultrasonic testing,radiographic testing, infrared thermography as well as electronic speckle patterninterferometry and shearographic testing. Besides the basic principles of testing usingthese methods, their potential applications in various industrial and technologicalbranches are broadly discussed. The analysis as categorization of the NDT methodsprovided in this paper may help in selection of such methods in diagnosis of varioustypes of structures and defects and damage occurring in these structures.

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.

Optical generation,detection and non-destructive testing applications of terahertz waves

Optoelectronic terahertz generation and detection play a key role in the applications of non-destructive testing,which involves different areas such as physics,biological,material science,imaging,explosions detection,astronomy applications,semiconductor technology and superconductiong electronics. In this article,we present a reviewof the principle and performance of typical terahertz sources,detectors and non-destructive testing applications. On this basis,the newdevelopment and trends of terahertz radiation detectors are also discussed.

Application Research of the Non-Destructive Testing Using Optical Fiber Sensor

In this paper, an optical fiber sensor is designed by using optical Faraday effect. It is composed of fiber collimator, polarizer, magneto-optical crystal and mirror. Based on the magnetic flux leakage (MFL) theory, The optical fiber sensor was placed between two permanent magnets with the N-pole. Therefore, the optical fiber sensing system was built to detect the defective ferromagnetic objects. Theoretical and experimental studies shown that the system can identify a little defects, such as irons’ blind hole (diameter φ =?3mm , depth t = 4mm?), irons’ grooves (length l= 30mm , width?ω = 10mm ), hole (φ?=?3mm ) and crackle etc. The system has the characteristics of small size, high sensitivity, fast signal response and high resolution. In terms of the defective oil and gas pipelines detection, The optical fiber sensing system is used in non-destructive testing, which will be valuable and meaningful.

Application of Non-destructive Testing to Evaluate the Performance of Bridges Structures

Bridges are important elements in road system and can influence the entire economy of cities and region. Usually, these structures have high financial investments for their constructions, in this way, maintenance and conservation become so important. Inspection is a technical activity that covers several operations, including performance analysis; examination; final performance report, other operations may be necessary, such as maintenance work, recovery, strengthening and rehabilitation. Technical examination together with some test methods allows a critical and parametric judgment of the bridge performance by minimizing the subjectivity of visual evaluations, and permits a more detailed diagnosis. This paper discusses the methodology to perform tests to complement the assessment recommended by DNIT （Brazilian National Department of Transport Infrastructure）, which consists only on a visual judgment. This approach provides technical basis to classify the bridges as its need and urgency of maintenance.

Non-Destructive Testing of Rods Using a Potential Component of a Magnetic Field

An essentially new method for non-destructive testing of elastic electrically conductive rods using non-vortex electromagnetic induction is proved theoretically. An experimental technique for defining a location of a cross crack is offered.

Inspection and testing stressed in standards comparison and compliance action

The symposium on inspection and testing bodies in the special action on standards comparison and complianee of 10,000 enterprises of 1,000 sectors in 100 cities was held in Beijing on April 16,which was attended by more than 70 representatives from SAMR and inspection and testing bodies.

Quality and Testing Standards on Rice Production in China and Development Strategies

China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualities are those aspects concerning processing, appearance,cooking, nutrition and safety of the product. The study, formulation and implementation of standardson rice qualities and testing bear heavily on the improving of rice qualities, human health,substitution of rice varieties, promoting quality rice production and regulating rice market.