Test Method For Evaluation Research Articles

Adaptive Ramanujan package decomposition method: a novel precise health indicator of rolling bearings

ABSTRACT In this paper, an adaptive Ramanujan packet decomposition (ARPD) method based on precise envelope segmentation is proposed to improve the accuracy of weak fault feature extraction and realise early non-destructive testing and condition evaluation of rolling bearings. Firstly, the power spectral density of the original signal is envelope-processed by accurate envelope segmentation method, so as to reduce the extreme points produced by interference frequency, and then realise the optimal frequency band division and reduce the influence of noise components. Secondly, the Ramanujan spectrum signal-to-noise ratio (RSSNR) index is introduced to quantify the fault characteristic information of the corresponding component in each frequency band. The largest component of the index is selected as the optimal mode, and the current number of layers is defined as the optimal number of modes. Finally, through the idea of iterative decomposition and RSSNR index, the problem that the optimal mode number is difficult to determine accurately is eliminated, and the optimal mode number is determined adaptively. The results of simulation and experimental signal analysis show that ARPD method can accurately divide the frequency bands and has excellent weak fault feature extraction ability, so it is an effective early non-destructive testing and condition evaluation method for rolling bearings.

Embedded Resistance as a Technique to Monitor Concrete Curing.

The use of membrane-forming curing compounds on fresh concrete has been widely adopted by many States' Departments of Transportation as it is feasible where there is a deficiency of water, on sloping surfaces where curing with water is challenging, and in cases where large areas like pavement have to be cured. However, the evaluation of the curing compound application effectiveness is difficult because most of the evaluation test methods are not performed during the early age of the concrete. Moreover, the ASTM C156 standards test of water retention for the qualification of curing compounds has met criticism as the moisture retention is performed only on the mortar specimens, with a fixed application rate and curing condition. Therefore, in this study, the embedded resistance technique was used as a test replacement for the moisture retention test to assess concrete curing. The findings from this study showed that a correlation can be found between the moisture retention test and the embedded resistance test. Based on the findings, the embedded resistance test could be a suitable replacement for the moisture loss test, because the test is much simpler and quicker to be performed both in the lab and in the field.

Combined Prediction of Dust Concentration in Opencast Mine Based on RF-GA-LSSVM

Accurate prediction of dust concentration is essential for effectively preventing and controlling mine dust. The environment of opencast mines is intricate, with numerous factors influencing dust concentration, making accurate predictions challenging. To enhance the prediction accuracy of dust concentration in these mines, a combined prediction algorithm utilizing RF-GA-LSSVM is developed. Initially, the random forest (RF) algorithm is employed to identify key features from the meteorological and dust concentration data collected on site, ultimately selecting five indicators—temperature, humidity, stripping amount, wind direction, and wind speed—as the input variables for the prediction model. Next, the data are split into a training set and a test set at a 7:3 ratio, and the genetic algorithm (GA) is applied to optimize the least squares support vector machine (LSSVM) model for predicting dust concentration in opencast mines. Additionally, model evaluation metrics and testing methods are established. Compared with LSSVM, PSO-LSSVM, ISSA-LSSVM, GWO-LSSVM, and other prediction models, the GA-LSSVM model demonstrates a final fitting degree of 0.872 for PM2.5 concentration data and 0.913 for PM10 concentration data. The GA-LSSVM model clearly demonstrates a strong predictive performance with low error and high fitting. The research results can serve as a foundation for developing dust control measures in opencast mines.

A state-of-the-art assessment in developing advanced concrete materials for airport pavements with improved performance and durability

Concrete materials, as the main component of airport pavement, provide essential attributes such as strength and toughness required by airport pavement. With the rapid development of air transportation, the compression and cracking resistance performances required by airport pavement are dramatically boosted with the ever-growing weight and the frequency of aircraft. In recent years, high-performance concrete materials with excellent properties have shown great potential in improving durability and extending the service life of pavement. This review presents a-state-of-the-art assessment guided by the pavement performance requirement, material design mechanism, application cases and future application guidance of advanced cementing materials in airport pavement improvement. Firstly, the functions of each structural layer of airport pavement and their effects on the surface layer are summarized. Then, the design mechanism and application cases of advanced concrete materials were summarized with the future application guidance to be given. Finally, the application scenarios, testing mechanism and testing effect of nondestructive testing methods for airport pavement performance evaluation are summarized. This review provides a comprehensive assessment of the development and applications of advanced concrete materials for airport pavement, paving avenue to achieve high performance and long service life of airport pavement.

Application of the non-linear three-component model for simulating accelerated creep behavior of polymer-alloy geocell sheets

The polymer-alloy geocell sheets (PAGS) represent a novel geocell material developed to replace conventional geocell materials. Accelerated creep testing, a convenient and precise performance evaluation method, presents a viable alternative to traditional creep testing for obtaining long-term creep strains. Nonetheless, there is a lack of prediction and in-depth exploration of accelerated creep testing. This paper aims to assess the efficacy of using the non-linear three-component (NLTC) model to simulate the accelerated creep behavior of PAGS. The predictive accuracy of the NLTC model has undergone evaluation through a comparison between stepped isothermal method (SIM) accelerated creep experimental tests and numerical simulations. Subsequently, the validated NLTC model was employed to simulate the time-temperature superposition method (TTSM), time-stress superposition method (TSSM), and stepped isostress method (SSM) accelerated creep tests, thereby verifying its effectiveness in predicting all accelerated creep tests. The results indicate that the NLTC model can effectively simulate creep deformation induced by temperature increases, particularly the temperatures below 41 °C. Although some errors are observed at elevated temperatures, it is within the acceptable range of 17.4%. Numerical simulation results of TTSM, TSSM, and SSM tests also suggest the model's proficiency in simulating the accelerated creep behavior by temperature and creep load increasing.

Effect and mechanism of the opening area on the shielding effectiveness of an electromagnetic shielding garment

The opening area has an important effect on the overall protective performance of electromagnetic shielding (EMS) garments, but its mechanism and influencing laws are not clear. In this paper, a semi-anechoic chamber is adopted to construct a testing system, and a tying and covering method is proposed to test the shielding effectiveness (SE) of the garment with different parameters of opening area. Combined with electromagnetic theory, experimental results are analyzed, and influence laws and mechanisms of the opening area on the overall SE of the garment are discovered. Based on this, some new ideas for designing and evaluating EMS garment are proposed. We conclude that the opening area has a reducing effect on the SE of the garment in the frequency range of 1–3 GHz. The larger the size of the opening area, the more obvious the effect is. When reaching a certain size, the value of overall SE reaches zero or can even be negative, resulting in a significant decrease in the protective performance of the garment or even complete loss of its protective effect. The distance between the opening and the test point has a significant influence on the SE of the garment: the closer the distance, the greater the influence is. The opening closest to the testing point has a decisive effect on the overall SE of the garment. The style of opening area has a significant influence on the SE of the garment: pleated or inclined shape can improve the SE. Based on the above rules, a multi-index comprehensive weighted testing evaluation method for an EMS garment that fully considers the influence proportion of each opening is proposed, providing a scientific reference for the design, production, testing, and evaluation of EMS garments.

The Combined Use of Fine-Needle Aspiration (FNA) and BRAF V600E Gene Testing: Can it Increase the Definitive Diagnosis Rate of Nodules Categorized as Bethesda III for Papillary Thyroid Carcinoma?

This study aimed to analyze the malignant probability of thyroid nodules diagnosed as indeterminate cytology, including atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS), and investigate the diagnostic value of combining BRAF V600E gene testing within this classification. We conducted a retrospective analysis of 126 patients who underwent fine-needle aspiration (FNA) examination of thyroid nodules and subsequent surgical treatment at Beijing Haidian Hospital between October 2021 and November 2022. Among them, there were 22 male and 104 female patients, aged between 18 and 75years old. Surgical pathology results were considered the gold standard for diagnosing the nature of thyroid nodules, evaluating the malignant incidence of cytological results categorized as AUS/FLUS. Fisher's exact test and diagnostic test evaluation methods were used to analyze the discriminatory diagnostic efficacy of preoperative FNA combined with BRAF V600E gene testing for papillary thyroid carcinoma (PTC). Statistical analysis was performed using SPSS 22.0 software. In PTC patients, the BRAF V600E gene mutation rate was 87.93% (102/116). Within the category of FNA results as AUS/FLUS, the proportion of PTC was 60.00% (15/25). The specificity, sensitivity, positive predictive value, and negative predictive value of the BRAF V600E gene mutation in diagnosing PTC within the AUS/FLUS category were 10/10, 6/15, 6/6, and 10/19, respectively. The BRAF V600E gene mutation significantly increased the detection rate of PTC in patients classified under this cytology (P = 0.028, <0.05). Preoperative FNA combined with BRAF V600E gene mutation testing significantly enhances the malignant detection rate of thyroid nodules diagnosed cytologically as AUS/FLUS. This combined approach provides a potent tool to improve diagnostic accuracy in this indeterminate classification.

Analysis and Comparison of Three Bending Tests on Phosphogypsum-Based Material According to Peridynamic Theory

Phosphogypsum-based materials have gained much attention in the field of road infrastructure from the economic and sustainable perspectives. The Three-point bending test, the Four-point bending test and the Semi-circular bending test are three typical test methods applied for fracture energy measurement. However, the optimal test method for fracture energy evaluation has not been determined for phosphogypsum-based materials. To contribute to the gap, this study aims to analyze and compare the three test methods for fracture energy evaluation of phosphogypsum materials based on the peridynamic theory. For this purpose, the load–displacement, vertical displacement–Crack Mouth Opening Displacement (CMOD) and fracture energy of the phosphogypsum-based materials were measured and calculated from the three test methods. The simulated load–displacement and vertical displacement–CMOD by PD numerical models, with different fracture energy as inputs, were compared to the corresponding tested values according to simulation error results. The results showed that the Four-point bending test led to minimized errors lower than 0.189 and indicators lower than 0.124, demonstrating the most optimal test method for the fracture energy measurement of phosphogypsum-based material. The results of this study can provide new methodological references for the selection of material fracture energy measurement tests.

Towards 3D Pore Structure of Porous Gypsum Cement Pozzolan Ternary Binder by Micro-Computed Tomography

A sophisticated characterisation of a porous material structure has been challenging in material science. Three-dimensional (3D) structure analysis allows the evaluation of a material’s homogeneity, pore size distribution and pore wall properties. Micro-computed tomography (micro-CT) offers a non-destructive test method for material evaluation. This paper characterises a novel ternary binder’s porous structure using micro-CT. Gypsum–cement–pozzolan (GCP) ternary binders are low-carbon footprint binders. Both natural and industrial gypsum were evaluated as a major components of GCP binders. Porous GCP binder was obtained by a foaming admixture, and the bulk density of the material characterised ranged from 387 to 700 kg/m3. Micro-CT results indicate that pores in the range from 0.017 to 3.0 mm can be effectively detected and described for porous GCP binders. The GCP binder structure proved to be dominant by 0.1 to 0.2 mm micropores. For GCP binders produced with natural gypsum, macropores from 2.2 to 2.9 mm are formed, while GCP binders with phosphogypsum possess pores from 0.2 to 0.6 mm. Micro-CT proved to be an effective instrument for characterising the homogeneity and hierarchical pore structure of porous ternary binders.

Causal relationships of health risk of air pollution in industrial area

Air contamination is one of the serious problems for the environment and the health of society. Air contamination risk assessment, health effects assessment tools are used to identify the place and time of public health effects and risk prevention strategies to reduce negative health effects. Considering that there may be a relationship between factors affecting risk, in this study, interactions between them are investigated using Fuzzy Decision Test and Experimental Evaluation Method (fuzzy DEMATEL). The cause of the health air contamination risk in an industrial area are the activity of industrial complexes and port (D+R=45.98, D-R=2.09) and the presence of hydrogen sulfide (46.82, 2.61), benzene (50.87, 2.87), sulfur dioxide (43.87, 4.32) and PM10 (53.51, 5.63) and the effects of these factors will affect the amount of carbon monoxide (39.56, -4.47), ozone (38.80, -4.20), nitrogen dioxide (50.33, -1.62) and PM2.5 (44.18, -1.26). Hospitals and nursing homes (49.01, -2.58), schools (50.99, -0.59), storage and industrial facilities, roads (45.72, -0.59), urban core (51.38, -0.55) and Natural zones, agriculture and waterways (48.86, -0.17) are affected by other factors. Population density is also affected by cause factors. Population density has a two-way relationship with PM2.5. The main human and social factors include GDP per capita and urbanization rate. Hydrogen sulfide has a one-way relationship with population density. People who work in certain industries may be exposed to higher amounts of hydrogen sulfide than the general population. These industries include the production of rayon textiles, pulp and paper factories, oil and natural gas drilling operations, and wastewater treatment plants. Therefore, by controlling the activity of industrial complexes, port and the amounts of hydrogen sulfide, benzene, sulfur dioxide and PM10 in the ambient air can be prevented from the effects after that.

Research on failure rate evaluation test method of energy meter in charging pile

Abstract To verify the failure rate of intelligent energy meter in charging pile and whether it can meet the reliability requirements in “general technical specification for single-phase intelligent electric energy meter (2020)”. Take 20 smart meter samples from four manufacturers, use the accelerated life model and carry out the accelerated test in the way of stress acceleration for a total of 4000 hours, and evaluate the failure rate indicators under normal working stress. The test results show that the single-phase intelligent watt hour meters produced by the four manufacturers can meet the reliability requirements such as annual failure rate index. The accelerated test theory is applied to the reliability life and failure rate evaluation of intelligent electric energy meter to shorten the test time, improve the test efficiency and reduce the test cost.

Advancements in 3D Printing: Directed Energy Deposition Techniques, Defect Analysis, and Quality Monitoring

This paper provides a comprehensive analysis of recent advancements in additive manufacturing, a transformative approach to industrial production that allows for the layer-by-layer construction of complex parts directly from digital models. Focusing specifically on Directed Energy Deposition, it begins by clarifying the fundamental principles of metal additive manufacturing as defined by International Organization of Standardization and American Society for Testing and Materials standards, with an emphasis on laser- and powder-based methods that are pivotal to Directed Energy Deposition. It explores the critical process mechanisms that can lead to defect formation in the manufactured parts, offering in-depth insights into the factors that influence these outcomes. Additionally, the unique mechanisms of defect formation inherent to Directed Energy Deposition are examined in detail. The review also covers the current landscape of process evaluation and non-destructive testing methods essential for quality assurance, including both traditional and contemporary in situ monitoring techniques, with a particular focus given to advanced machine-vision-based methods for geometric analysis. Furthermore, the integration of process monitoring, multiphysics simulation models, and data analytics is discussed, charting a forward-looking roadmap for the development of Digital Twins in Laser–Powder-based Directed Energy Deposition. Finally, this review highlights critical research gaps and proposes directions for future research to enhance the accuracy and efficiency of Directed Energy Deposition systems.

Multisite studies for optimization of a highly efficient culture assay used for in vitro detection of residual undifferentiated human pluripotent stem cells intermingled in cell therapy products

IntroductionMEASURE2 (Multisite Evaluation Study on Analytical Methods for Non-clinical Safety Assessment of HUman-derived REgenerative Medical Products 2) is a Japanese experimental public–private partnership initiative that aims to standardize testing methods for tumorigenicity evaluation of human pluripotent stem cell (hPSC)-derived cell therapy products (CTPs). MEASURE2 organized multisite studies to optimize the methodology of the highly efficient culture (HEC) assay, a sensitive culture-based in vitro assay for detecting residual undifferentiated hPSCs in CTPs. MethodsIn these multisite studies, 1) the efficiency of colony formation by human induced pluripotent stem cells (hiPSCs) under two different culture conditions and 2) the sorting efficiency of microbeads conjugated to various anti-hPSC markers during hiPSC enrichment were evaluated using samples in which hiPSCs were spiked into hiPSC-derived mesenchymal stem cells. ResultsThe efficiency of colony formation was significantly higher under culture conditions with the combination of Chroman 1, Emricasan, Polyamines, and Trans-ISRIB (CEPT) than with Y-27632, which is widely used for the survival of hPSCs. Between-laboratory variance was also smaller under the condition with CEPT than with Y-27632. The sorting efficiency of microbeads conjugated with the anti-Tra-1-60 antibody was sufficiently higher (>80%) than those of the other various microbeads investigated. ConclusionsResults of these multisite studies are expected to contribute to improvements in the sensitivity and robustness of the HEC assay, as well as to the future standardization of the tumorigenicity risk assessment of hPSC-derived CTPs.

Classification, Structure and Construction of Functional Orthopaedic Compression Knits for Medical Application: A Review

Analysis of functional products for medical textiles indicates that there are plenty of different classifications of this group. Requirements for compression generated by compression garments differ depending on the application area, and even more, sometimes are contradictory and can be fulfilled in very different ways. The effectiveness of such products depends on mechanical and physical properties as well as psychological barriers. Currently, there is no uniform classification of compression classes, furthermore, there is no uniform standard, test method or technic for evaluation of the product’ compression. Knitted compression fabrics are made by knitting together at least two types of yarns: a ground yarn which ensures stiffness and thickness and an elastomeric yarn which generates compression. Knitted compression products can be produced on both flat and circular knitting machines, though parameters and usage of production are different. Additional elements used in the structure of the compression product can significantly change the generated compression. Purposes and number of additional details depend on the application and functionality of the compression support, nevertheless, all rigid elements must be taken into account at the designing stage. Additional functionality like antimicrobial activity or thermal therapy can also be provided for compression knits. It is highly important to ensure the longevity of all functional properties.

Comparative analysis of time sweep testing evaluation methods for the fatigue characterisation of aged bitumen

Ageing of bitumen changes its stiffness related properties and is thought to have a considerable impact on its fatigue performance. Time sweep tests are a commonly used methodology to evaluate the fatigue performance of bitumen over the course of its lifetime. This study comparatively evaluated the fatigue performance of six aged bitumen samples using various commonly employed time sweep testing-based approaches, including conventional methods (50% reduction in complex modulus and peak in phase angle) and newer methods (peak in S × N and two dissipated-energy-based approaches). The statistical analysis of the results illustrated that although the trends of fatigue life versus ageing levels were similar, different methods had significantly varying results. It was generally seen that ageing increased stiffness and the calculated fatigue life of bituminous binders improved when commonly applied strain levels of 5% and 7.5% were used. This result demonstrates the need to develop more robust methods to fully capture the true fatigue related deterioration of aged binders in the future. Among all the methods, the peak in S × N approach was found to be the most efficient based on the criteria used in the study and was the recommended approach considering current limitations. It showed no apparent defects and had the best correlations with other methods when the applied strains were 5% and 7.5%.

Test method for evaluation of ability for recovery of hydrophobicity of composite insulators

Test method for evaluation of ability for recovery of hydrophobicity of composite insulators

Analysis of the Interference Effects in CMOS Image Sensors Caused by Strong Electromagnetic Pulses

With the electromagnetic environment becoming increasingly complex, it is crucial to address the risk posed by electromagnetic pulse, which critically impairs the performance and reliability of electronic systems based on complementary metal oxide semiconductor (CMOS) image sensors. In this context, research on the failure types of CMOS image sensors in a high-power electromagnetic environment, caused by strong electromagnetic pulses and the rapid evaluation method of interference immunity, has garnered significant interest. This paper conducts electromagnetic pulse simulation experiments on CMOS image sensors to first study their failure types, such as image abnormalities and functional interruption, and then identify the corresponding failure criteria. Furthermore, this study builds on the small sample test evaluation method to investigate the interference threshold of functional interruptions in CMOS image sensors by calculating the failure probability at different field strengths. The obtained data were combined with the Weibull distribution function for fitting, the results of which found the interference threshold to be at 40.4 kV/m. The findings of this study provide a basis for evaluating the survivability of CMOS image sensors and their associated reinforcement technology in high-power electromagnetic environments.

Design of Pseudo-random Sequence Generator based on Three-dimensional Discrete Chaotic System

In this paper, a pseudo-random sequence generator with better randomness is constructed through the targeted improvement of chaotic system. Firstly, a new three-dimensional discrete chaotic system is proposed on the basis of the existing one-dimensional logistic chaotic system by improving and optimizing the dimensionality and coupling mode, and its Lyapunov exponent and other characteristics are analyzed; then, based on the chaotic system, a pseudo-random sequence generator is designed by using post-processing and heterodyne, etc.; after that, the performance of the pseudo-random sequence is discussed by using the evaluation methods of relevance, homogeneity, and NIST test. After that, the performance of the pseudo-random sequence is discussed using correlation, uniformity, NIST test and other evaluation methods. The results show that the three-dimensional discrete chaotic system has good chaotic properties, and the pseudo-random sequence generator based on this three-dimensional discrete chaotic system has good random performance and can pass the NIST test. The work in this paper provides an idea for the improvement of logistic mapping chaotic system and enriches the application form of pseudorandom sequence generator in information security.

Advanced testing and characterization of low-temperature cracking in bitumen and mastic

Low-temperature cracking is one of the most common failures in asphalt pavements, especially in cold regions. Accordingly, considerable amount of research has been performed in order to understand the low-temperature cracking mechanisms and to propose test methods for characterizing and determining cracking performance of bitumen and asphalt mixtures under freezing conditions. The existing test methods, however, require expensive equipment and skilled technicians; they are thus not well suited for routine tests. As a contribution to mitigate this situation, this study intends to investigate experimentally and characterize numerically the low-temperature cracking behavior of bitumen and mastic materials using a refined thermal cracking test method. The proposed method, the annular restrained cold temperature induced cracking (ARCTIC) test, allows to determine the low-temperature cracking properties of the mastic and bitumen with a relatively simple setup. In this paper, finite element (FE) modeling is used for evaluating the effect of test parameters on the temperature, stress and strain gradients induced in the specimen during the test. The ARCTIC test is employed to measure cracking temperatures of two bitumen and two mastic materials. The measurements repeatability is examined and the effect of bitumen type on the thermal cracking potential of bitumen and mastic is evaluated. FE modeling is employed to examine the effect of thermomechanical parameters on thermal cracking performance of the materials and to back-calculate fracture stress and strain from measurements. The results highlight the potential of the proposed test and analysis method for evaluation of low-temperature cracking in bitumen and asphalt mastic.

Development of Index System and Test Method for Table Tennis Sports Skill Evaluation in Primary and Secondary Schools

Development of Index System and Test Method for Table Tennis Sports Skill Evaluation in Primary and Secondary Schools