Test Methodology Research Articles

Long-term skid resistance evolution and influence mechanism of asphalt pavement based on self-developed wear equipment

Skid resistance decay is the critical functional distress of asphalt pavement, directly restricting its safety and service life. In order to grasp the characteristics and mechanism of long-term skid resistance evolution, this study developed a laboratory wheel-accelerated wear equipment (WAWE) and its testing methodology for asphalt pavement and coarse aggregate. Five coarse aggregates and five gradations combinations were selected to investigate the evolution. The accuracy of the evolution model and the loading conversion relationship were analyzed based on the Research Institute of Highway (RIOH) Track. Finally, the pavement anti-skid texture tester (PATT) was used to investigate the evolution characteristics of coarse aggregate microtexture. Results showed that the Asymptotic evolution model could characterize the skid resistance under the influence of coarse aggregate and gradation. RIOH Track verified the model's accuracy and showed that a single WAWE wear was equivalent to 265 loading times on actual pavement. The long-term skid resistance could be improved by increasing the nominal maximum particle size and the gradation fractal dimension indexes D and Df. The microtexture roughness of the coarse aggregate decreased after wear, then stabilized and fluctuated, which showed "regeneration" characteristics. The study can guide asphalt mixture design and maintenance timing decisions based on long-term skid resistance.

Hybrid Testing System Development for Single Point Mooring Lines FOWT’s

Abstract To advance the development of various concepts for floating offshore wind turbines, it is imperative to have access to experimental data. These data are used in the validation of the tools for the simulation of floating turbines and also for the tuning of the models. CENER has developed a hybrid testing methodology that enhances the performance of wave basin tests for scaled models of Floating Offshore Wind Turbines (FOWTs). This approach allows us to apply forces and moments from the wind turbine to the floating platform without needing to replicate wind within the testing facility or create a complex model of the wind turbine rotor. However, when it comes to testing single point moored (SPM) platforms, a unique challenge arises. These platforms have an additional degree of freedom as they can freely rotate around the vertical axis of their mooring attachment (yaw degree of freedom). These type of platforms can present important misalignments with respect to the wind depending on the combination of wind, wave and current directions. Consequently, accurately capturing the impact of misalignment on platform dynamics, especially in yaw, is essential to assess the platform’s ability to self-align with the wind direction, a key factor known as weathervaning capacity. The X1Wind platform is an innovative floating wind system, based on a single point mooring solution with a downwind wind turbine configuration that allows it to be passively self-orientated. The concept has been extensively tested on prototypes at real sea conditions as well as on scaled models at wave basins. For the last wave basin testing campaign, X1Wind has entrusted CENER with the development of the hybrid testing methodology adapted to the requirements of SPM platforms. The testing campaign has covered different wave and wind conditions, including misalignment scenarios and has shown a good dynamic behavior of the platform on yaw. This study outlines the advancements made in the CENER Software-in-the-Loop (SiL) hybrid testing system for wave basin tests of SPM platforms. In order to correctly introduce the direction of the aerodynamic forces on the wind turbine under misaligned conditions, improvements on the software and hardware (loads actuator) of the SiL system were developed and tested. An actuator system consisting of 6 propellers was used. The numerical model that calculates the rotor aerodynamic loading were expanded to take into consideration the direction of the aerodynamic loads with respect to the platform. Additionally, the drag of the wind over the tower and other platform elements must be considered, as they can play a relevant role in the generation of the weathervaning moment. The study concludes that the use of the upgraded SiL hybrid testing system is an effective and afordable solution for the testing of scaled SPM platforms at wave basin facilities. It also summarizes the different considerations that the system has to overcome for the particularity of this type of testing application.

Observational Causality Testing

ABSTRACTIn prior work, we have introduced an asymptotic threshold of sufficient randomness for causal inference from observational data. In this paper, we extend that prior work in three main ways. First, we show how to empirically estimate a lower bound for the randomness from measures of concordance transported from studies of monozygotic twins. Second, we generalize our methodology for application on a finite population, and we introduce methods to implement finite population corrections. Third, we generalize our methodology in another direction by incorporating measured covariate data into the analysis. The first extension represents a proof of concept that observational causality testing is possible. The second and third extensions help to make observational causality testing more practical. As a theoretical and indirect consequence of the third extension, we formulate and introduce a novel criterion for covariate selection. We demonstrate our proposed methodology for observational causality testing with numerous example applications.

Methodological Approach for the Development of Standard C-UAS Scenarios

The integration of unmanned aircraft systems (UAS), commonly referred to as drones, into various sectors including agriculture, healthcare, and military operations has transformed industries and services. While drones offer numerous benefits, they have also been exploited by terrorists and criminals for illicit activities, such as smuggling and surveillance. Incidents involving drones flying over restricted airspaces or sensitive locations have highlighted the vulnerabilities of critical infrastructure and limitations of current law enforcement capabilities. To address these challenges, there is a growing need for effective counter-UAS (C-UAS) systems including detection, tracking, and identification technologies. However, evaluating the capabilities of these systems poses a significant challenge, leading to the demand for standardized test methodologies. The COURAGEOUS project seeks to fill this gap by developing standardized scenarios covering various use cases, such as airport security, critical infrastructure protection, and border security. These scenarios are informed by a systematic approach involving a literature review, analysis of previous incidents, assessment of current C-UAS frameworks, and gathering feedback from end users. The resulting standardized test methodology aims to enhance the understanding of C-UAS system capabilities, improve preparedness against evolving threats, and facilitate the global dissemination of project results. Through validation trials and feedback from law enforcement agencies, the COURAGEOUS project strives to contribute to a broader network of counter-UAS initiatives, ultimately enhancing the lower airspace security.

Development of an Improved Thiosulfate-Utilizing Denitrifying Bacteria-Based Ecotoxicity Test with High Detection Sensitivity and Reproducibility

Microorganism-based ecotoxicity assessment has been widely used as a reliable tool showing direct biochemical impacts of contaminants on ecosystems and the environment. The present study aimed at developing a thiosulfate-utilizing denitrifying bacteria (TUDB)-based ecotoxicity test with high detection sensitivity and favorable reproducibility. To achieve this goal, existing TUDB toxicity tests were improved by employing a pure culture of Thiobacillus thioparus ATCC 8158 and optimizing test conditions, particularly in terms of inoculated microbial biomass, incubating temperature, and operational pH. From control tests, it was found that 4 h is a sufficient processing time for TUDB test kits. As a result of optimization, 20 mg VSS/L of initial bacterial biomass, 25 °C of incubating temperature, and 6 of operational pH were determined as the most favorable test conditions, providing enhanced detection sensitivity and reproducibility. Under these optimal test conditions, I conducted toxicity tests for diverse toxic metals and obtained 0.65 ± 0.03, 1.09 ± 0.04, 1.21 ± 0.07, 0.13 ± 0.01, 0.56 ± 0.04, 1.42 ± 0.03, 0.98 ± 0.02, and 2.12 ± 0.05 mg/L of 4 h EC50 values for Ag+, As3+, Cd2+, Cr6+, Cu2+, Hg2+, Ni2+, and Pb2+, respectively. These EC50 values are substantially lower than those from earlier TUDB tests, demonstrating the high detection sensitivity of the current TUDB tests. Moreover, the present TUDB tests attained very low coefficient of variation (CV) values (1.6–6.3%) for the EC50, showing favorable reproducibility of the test methodology. In addition, the current TUDB toxicity tests offer numerous advantages for ecotoxicity assessment, including versatility for diverse test samples, no requirement for advanced equipment, and no distortion of end-point measurement. These refinements render the TUDB tests a favorable ecotoxicity assessment with enhanced sensitivity and reproducibility.

Testing for genetic and viral etiologies in congenital hearing loss based on a survey of cochlear implant centers: proposed HEARRING group consensus and future directions

Background In cases of congenital sensorineural hearing loss, testing for genetic etiologies and congenital cytomegalovirus (cCMV) infection have become common practice. Aims/Objectives The purpose of this study is to determine which specific testing methodologies should be used and when. Material and methods We surveyed 20 practicing otolaryngologists across eighteen institutions in thirteen countries about their approach to cCMV, GJB2, and wider genetic testing. Results We found 90% of respondents employ all three tests, either in routine or special cases. cCMV testing is widely used, with 95% of respondents incorporating it into their clinical practice. GJB2 testing was employed by 90%. In cases with negative GJB2 test results, a majority of respondents proceeded to wider genetic screening. Test reimbursement was also examined for each test. For cCMV testing, 63.1% reported reimbursement, 68.4% reported reimbursement for GJB2 variant testing and 52.6% reported reimbursement for wider genetic screening. Conclusions and significance A common approach is to perform cCMV and GJB2 testing as the first tests, followed by wider genetic testing. This study offers insight into the prevalence, methodologies, and reimbursement status of these testing methodologies across multiple hearing centers and countries. Current consensus and future directions are described based on the current survey.

CORONATING VOLTAGE DIVIDER OF MEGAELECTRONVOLT ACCELERATING TUBE

This paper describes the methodology of high-voltage testing of the voltage divider of a positively charged ion accelerating tube for energies up to 1000 keV. The test results are presented, and a simple engineering method for calculating the corona voltage divider is proposed.

Contact dermatitis secondary to povidone-iodine: A systematic review.

Cutaneous reactions to povidone (PVP)-iodine are widely reported; however, distinction between allergic and irritant reactions can be challenging. Free iodine is responsible for irritant reactions and is released when PVP-iodine is in a liquid state. The aim of this study was to review the clinical presentation and results of patch testing in patients with PVP-iodine contact dermatitis. A systematic review was conducted by searching Pubmed, MEDLINE, and Google Scholar databases for reports of contact dermatitis secondary to PVP-iodine. Data were collated including study design, patient age and gender identity, iodine exposure, skin biopsy findings, and patch test methodology and results. The search revealed 187 reports with 38 eligible studies; 30 case reports/case series and 8 retrospective cohort studies. Overall, there were 223 patients with PVP-iodine contact dermatitis. The commonest reaction was irritant contact dermatitis (51%), followed by allergic contact dermatitis (40%) and contact dermatitis not further specified (9%). Irritant reactions were characterised by burn-like morphology and, when due to surgical skin disinfectant, were often distant from the surgical incision site. Patch testing was most often performed with a 10% PVP-iodine aqueous solution; however, irritant reactions in controls occur. Various testing methods including iodine in petrolatum, ethanol, dried powder, and open application testing were described. Most reactions to PVP-iodine are irritant and patch testing using a closed-chamber method yields inconsistent results due to risk of irritation from free iodine release over the 2-day occlusion time. Surgeons should be aware of the risk of prolonged skin contact with wet iodine solution.

Research on Electric Vehicle Powertrain Systems Based on Digital Twin Technology

As a critical component of electric vehicles, the powertrain has a significant impact on the overall performance of vehicles. In addressing the challenge of lengthy testing cycles, this study develops a para model of the powertrain, utilizing digital twin (DT) technology, thereby establishing a framework for simulation testing of multi-controller intermodulation. We establish functional definition coverage testing by designing specific functional requirement use cases, and we validate the failure mechanism via fault injection use cases. The results indicate that the DT testing platform can effectively simulate the operational interactions among various controllers within the powertrain system. In comparison to traditional field testing, the digital twin-based testing methodology offers enhanced operational efficiency and allows for the examination of testing conditions that are impractical to implement in real vehicles, particularly in the context of fault injection testing, thus facilitating the early detection of potential safety risks within the system. The advancement of this technical solution holds significant practical implications for the future mass production and development of electric vehicles.

High and very high cycle fatigue behavior of an additive manufactured hot-work tool steel

In the present study, the fatigue response of an additive manufactured H13 type hot-work tool steel is investigated across the High Cycle Fatigue (HCF) and Very High Cycle (VHCF) regimes. The primary focus encompasses the interpretation of fatigue strength models, the defect type analysis along with a detailed examination of crack initiation and growth mechanisms. Despite the tremendous development in AM technology, experimental data regarding advanced mechanical properties, and particularly fatigue behavior, are still limited. Here, microstructural analysis of a modified AMed H13 hot-work tool steel, a combination of HCF and VHCF testing methodologies implemented for the characterization of the fatigue behavior, as well as a thorough fractographic analysis of the fractured surfaces were performed. Results are compared with historical data of a conventionally ingot cast and forged grade to assess the influence of the AM process on the fatigue response of H13 hot-work tool steels. It proves to be comparable to the conventionally manufactured grade, showcasing the potential utilization of AM in the production of components used in high-demanding applications, and in hot work tooling applications. However, the type of critical defects identified in the AM grade was found to be process-induced, emphasizing the need to optimize process parameters to reduce both the number and size of defects and also to ensure component reliability and high performance in various industrial applications.

Similarity-driven adversarial testing of neural networks

Although Convolutional Neural Networks (CNNs) are among the most important algorithms of computer vision and the artificial intelligence-based systems, they are vulnerable to adversarial attacks. Such attacks can cause dangerous consequences in real-life deployments. Consequently, testing of the artificial intelligence-based systems from their perspective is crucial to reliably support human prediction and decision-making through computation techniques under varying conditions. While proposing new effective attacks is important for neural network testing, it is also crucial to design effective strategies that can be used to choose target labels for these attacks. That is why, in this paper we propose a novel similarity-driven adversarial testing methodology for target label choosing. Our motivation is that CNNs, similarly to humans, tend to make mistakes mostly among categories they perceive similar. Thus, the effort to make models predict a particular class is not equal for all classes. Motivated by this, we propose to use the most and least similar labels to the ground truth according to different similarity measures to choose the target label for an adversarial attack. They can be treated as best- and worst-case scenarios in practical and transparent testing methodologies. As similarity is one of the key components of human cognition and categorization, the approach presents a shift towards a more human-centered security testing of deep neural networks. The obtained numerical results show the superiority of the proposed methods to the existing strategies in the targeted and the non-targeted testing setups.

Using Latin Square Methodology to Test Vocabulary through Story Reading

Recognizing the need for objectivity when assessing readers' comprehension across multiple iterations and texts, the study explores how the traditional Latin Square design can be refined to accommodate such requirements. This paper delves into the application and adaptation of Latin Square methodology in vocabulary testing through multiple readings of stories. By examining the challenges and opportunities presented by multi-pass reading materials, the paper proposes strategies to enhance the validity and reliability of vocabulary assessments, ensuring that readers' performance is accurately captured and analyzed

Impact of Illuminant Metamerism on Colour Fidelity in Graphic Reproduction of Artistic Images

The aim of the research was to to evaluate the quality of illuminant metamerism by using Colour rendering index through similar paintings and half-tone reproduction images within the graphic industry. Employing the methodology of visual perception and testing conducted by standard observers, the study scrutinises how different colour techniques of paintings respond to diverse light sources under standardised conditions. This investigation is pivotal for understanding the chromatic fidelity and consistency of paintings and their reproduction with half-tone colours, by measuring the grey balance field, for all images. To find the most suitable light source and to complete the colour quality, the Osram LED light at 3000 K, 4000 K, and 6500 K is used. The resulting index could be deceptive in cases of significant disparities. The American IES TM-30-18 colour rendering index (CRI) metric, quantifies illumination metamerism's ability to faithfully depict natural colours. At every stage (R1–R15), the average colour reproduction CRI must be more than 90.

Methodology for Testing Selected Parameters of Low-Current Vacuum Electric Arc

This article presents the author’s methodology for testing selected parameters of a low-current vacuum arc, implemented using an innovative test stand based on a vacuum discharge chamber with a contact system mounted inside. In order to verify the validity of the adopted research methodology, as well as the correctness of the operation of the developed laboratory bench, measurements and calculations were made, among other things, of the energy and burning time of the vacuum arc, depending on selected factors, such as pressure and the delay time of the contact opening, calculated from the “passage through zero” of the sinusoid of the current flowing through the system. The tests were performed at 230 V and a current of 5 A for two pressure values: p1 = 1.00 × 105 Pa (atmospheric pressure) and p2 = 4.00 × 10−3 Pa (high vacuum environment). It was found that the vacuum insulation technique allows a significant reduction in the value of the arc energy and the burning time of the arc. It was also observed that in the case of a high vacuum environment, the ignition of the vacuum arc occurs after a time equal to about 3 ms from the “passage through zero” of the current flowing through the system. Below this value, the phenomenon did not occur. The results obtained provide an opportunity for the design and manufacturing of vacuum switchgear, where there is the prospect of reducing the negative effects associated with the arc burning process in the contact gap.

Assessment of local mechanical properties of laser powder bed fused aluminium alloy by non-destructive testing based on FIMEC indentation

Laser powder bed fusion process is a versatile metal additive manufacturing process. Although significant progress has been made so far, there is still limited large-scale adoption of this technique by the industry. The main problems are repeatability and lack of proper knowledge. In this work, an innovative and non-destructive testing methodology, based on flat-top cylinder indentation, was used to define the mechanical properties of laser powder bed fused aluminium alloy to highlight any variations induced by the combination of process parameters, for global characterization, and by the building direction, for local characterization. Results show similar or improved global mechanical properties of the laser powder bed fused specimens when compared to traditional die-casted ones. Indentation tests highlight a local dependence of properties along the building direction in favor of the upper part of the samples.

Testing Mortars for 3D Printing: Correlation with Rheological Behavior

Three-dimensionally printed concrete is a transformative technology that addresses housing shortages due to population growth and enables innovative architectural designs. The objective of this study is to investigate the connection between a conventional test and the rheological properties of 3D-printed concrete. A more precise assessment of material quality based on traditional evaluation techniques is proposed. Standard tests are conducted to evaluate the consistency of 3D-printed concrete materials. Complementarily, a rheometer is employed to accurately measure key rheological properties, thereby establishing a link with empiric testing methodologies. The correlation between the flow table test and rheological coefficients, such as yield stress and viscosity, has been identified as the most effective in basic experiments for evaluating material behavior. This approach allows for a preliminary assessment of printability without the need for additional complex equipment. The study has successfully established a relationship between flow table tests and rheological parameters. However, further research involving a broader range of materials and print-test experiments is essential to enhance the correlation between other conventional testing methods and rheometer results.

Development of a methodology for assessing economically useful signs of hyssop

Hyssop (Hyssopus officinalis L.) refers to valuable spicy-aromatic, essential oil and medicinal crops and is widely used in traditional and folk medicine, perfumery, cosmetology, cooking and food industry. The main directions of selection of hyssop are increasing productivity, obtaining forms adapted to industrial cultivation technology, resistance to pests and diseases, valuable chemical and biochemical composition, different terms of onset of economic suitability, honey productivity, zoning (suitability for cultivation in specific soil and climatic conditions). The article presents the results of studies on the evaluation of the breeding material of hyssop by a complex of economically useful morphological, morphometric and phenological traits, including a new zoned author’s variety of the Belarusian State Agricultural Academy Zaveya. As a result of the research, the methodology for testing the distinctiveness, uniformity and stability of hyssop has been improved, which makes it possible to optimize the breeding process of this crop and conduct an extended assessment of the identification of varieties during state variety testing. The national methodology for testing for distinctiveness, uniformity and stability provides an opportunity for breeders to pay attention to the relevant characteristic and distinctive features of hyssop, which will contribute to the effective conduct of further breeding work to create forms and varieties with various economically valuable properties.

The Effect of Inflation, Interest Rates and Non-Performing Loans On Stock Returns Through Profitability In Banking Companies Indonesia Period 2018-2022

Even if the Indonesian economy has grown and the stock market has improved after COVID-19, banking stock returns in Indonesia have remained stagnant. The returns on Indonesian banking stocks in 2022 were much lower than in prior years. Identifying the internal and external variables that contributed to the fall in these shares is an obvious challenge. The purpose of this study is to investigate how return on assets (ROA) acts as a mediator between inflation, interest rates, non-performing loans, and stock returns. Thirty businesses make up the sample for this study, which employs testing methodologies including multiple regression and route analysis. Additionally, in order to find the indirect impact, the Sobel test must be used. This study found that stock returns are positively affected by inflation and return on assets, but unaffected by interest rates and non-performing loans. Unlike inflation and interest rates, return on assets can moderate the impact of non-performing loans on stock returns. stock performance. Things that could affect future returns should be carefully considered by investors.

CALCULATION OF BEARING CAPACITY AND SUBSIDENCE OF INITIAL EMBAY IN IN REK “OSLOMEJ” - KICHEVO, R. NORTH MACEDONIA

This paper presents the geomechanical conditions for the construction of a landfill for ash and slag in REK Oslomej - Kicevo, R. North Macedonia. In this context, geotechnical investigation works and laboratory tests on the construction site, as well as the research and test methodology, are presented, and the obtained results are given in the form of appropriate graphic attachments, tabular views and diagrams. In the second part of the paper, an analysis of the geomechanical conditions for the performance of the ash and slag landfill is made, referring to the conditions for the performance of the projected initial embankments. Several aspects have been analyzed, i.e. the bearing capacity of the base constructed from tailings materials which are characterized by relatively low values of the strength and deformable parameters, forecast subsidence of the base, the possibility of underfoot sliding on the slopes of the embankments, as well as technical conditions for the construction of the embankments themselves. It should be noted that all analyzes are made with assumed values of the material to be incorporated in the embankments, which should be quantitatively and qualitatively defined after the selection of the location for the loan. However, it is appreciated that these analyzes will make their own contribution and will realistically show the expected situation during exploitation of the landfill.

A NOVEL WAY TO CLASSIFY THE SLAKE DURABILITY INDEX OF ROCKS

Slaking, the disintegration of rocks upon exposure to moisture and air, poses significant challenges in engineering applications, such as in slope stability and embankment design. This study improves the slake durability index test by introducing several enhancements to better reflect the field conditions of rocks. A new test methodology is developed which includes a revised slake durability classification table, a novel Discard Method for calculating weight retention in the test drum, and an updated classification chart. The improved methodology considers parameters such as porosity and strength, evaluated through index, Schmidt hammer rebound and point load tests. The new classification table categorizes rocks into durability classes according to the field observations and laboratory test results. The Discard Method improves accuracy by eliminating broken pieces from the durability calculation, addressing the limitations in the suggested method. A Configured Discard Method equation further defines the durability estimation by combining porosity, strength and slake durability data. Field investigations and laboratory tests conducted with various rock types demonstrate that the new classification system provides more accurate and practical assessments of rock durability. This study highlights the importance of effective porosity and strength impact which enhance the reliability of slake durability evaluations, offering a revised classification framework that simplifies field assessments while maintaining the accuracy. Future research should focus on developing these methods and expanding their applicability to diverse geological contexts by including more material to test.