Test Methods Research Articles

Study of hydrogen embrittlement in steels using modified pressurized disks

The integration of hydrogen into natural gas pipelines presents challenges due to Hydrogen Embrittlement (HE), requiring critical material selection and testing methods. One such test is the Disk Pressure Test (DPT), which consists in pressurizing a clamped disk to failure. However, failure happens often at the clamping zone, making analysis difficult. This study aims to develop new disk geometries to control failure location while maintaining the test setup. Using two steel grades (a vintage X52 pipeline steel and a modern E355 modified steel with potential for pipeline use), new disk geometries were tested under helium and hydrogen at various pressure rise rates. Results show successful displacement of failure away from the clamping zones, demonstrating the effectiveness of the new geometries. Hydrogen embrittlement is demonstrated by comparing failure pressures under helium and hydrogen at various pressure rise rates. Using both material testing and simulation, this study provides insights into hydrogen embrittlement.

Equation-of-motion regularized orbital-optimized second-order perturbation theory with the density-fitting approximation.

The density-fitted equation-of-motion (EOM) orbital-optimized second-order perturbation theory (DF-EOM-OMP2) method is presented for the first time. In addition, κ-DF-EOM-MP2 and κ-DF-EOM-OMP2 methods are implemented with the addition of κ-regularization. The accuracy of the DF-EOM-OMP2, κ-DF-EOM-MP2, and κ-DF-EOM-OMP2 methods are compared to the density-fitted EOM-MP2 (DF-EOM-MP2), EOM coupled-cluster (CC) singles and doubles (DF-EOM-CCSD), and EOM-CCSD with the triples excitation correction model [EOM-CCSD(fT)] for excitation energies of many closed- and open-shell chemical systems. The excitation energies computed using different test cases and methods were compared to the EOM-CCSD(fT) method and mean absolute errors (MAEs) are presented. The MAE values of closed- and open-shell cases (closed-shell organic chromophores set, open-shell set, peptide radicals set, and radical set) according to the EOM-CCSD(fT) method show that the κ-regularization technique yields highly accurate results for the first excited states. Our results indicate that the κ-DF-EOM-MP2 and κ-DF-EOM-OMP2 methods perform noticeably better than the DF-EOM-MP2 and DF-EOM-OMP2 methods. They approach the EOM-CCSD quality, at a significantly reduced cost, for the computation of excitation energies. Especially, the κ-DF-EOM-MP2 method provides outstanding results for most test cases considered. Overall, we conclude that the κ-versions of DF-EOM-MP2 and DF-EOM-OMP2 emerge as a useful computational tool for the study of excited-state molecular properties.

EHealth and mHealth in Antimicrobial Stewardship Programs

Background: The global need for rapid diagnostic methods for pathogen identification and antimicrobial susceptibility testing (AST) is underscored by the increasing bacterial resistance and limited therapeutic options, especially critical in sepsis management. Summary: This review examines the aspects of the eHealth and mHealth in Antimicrobial Stewardship Programs (ASPs) to improve the treatment of infections and rational use of antimicrobials. Key Messages: The evolution from traditional phenotype-based methods to rapid molecular and mass spectrometry techniques has significantly decreased result turnaround times, improving patient outcomes. Despite advancements, the complex decision-making in antimicrobial therapy often exceeds the capacity of many clinicians, highlighting the importance of ASPs. These programs, integrating mHealth and eHealth, leverage technology to enhance healthcare services and patient outcomes, particularly in remote or resource-limited settings. However, the application of such technologies in antimicrobial management remains underexplored in hospitals. The development of platforms combining antimicrobial prescription data with pharmacotherapeutic algorithms and laboratory integration can significantly reduce costs and improve hospitalization times and mortality rates.

Study of the effects of shallow-buried charge parameters on the lower limb injuries of occupant in special vehicle body

In the process of military missions, special vehicles often encounter shallow buried charge threats that will greatly affect the safety of the occupants. To study the integrated effects of shallow buried charge detonation point, height-to-diameter ratio, burial inclination, weight, and other key parameters on the lower limb injuries of occupant, this study was based on the special body of a shallow buried explosive test and numerical calculation methods. The reliability of the numerical model and the load effect mechanism of the shallow burial charge were studied. Based on this, the lower limb injuries response law of occupant was analyzed with respect to each parameter. The results showed that the bottom charge load mainly came from two-stage ejection loading, in which the first stage was a strong load with short-duration local impact loading and the second stage was a weak load with long-duration extended range loading. By comparing the lower limb injury response of occupant under different charge parameters, we found that the weight of charge had the greatest effect on the extent of occupant injury, followed by the height-to-diameter ratio and burial inclination, while the detonation position had a relatively small effect on the injury magnitude. Finally, a comprehensive prediction model of the lower limb injuries of occupant was obtained by using the Latin hypercube sampling method and the least-squares method, and it was verified that the model had a good matching accuracy.

Challenges in Ground-Penetrating Radar Application in Structural Elements: Determination of the Dielectric Constant of Glued Laminated Timber Case Study

In this paper, some of the basic information on Ground-Penetrating Radar (GPR), its applications (especially in the field of civil engineering) and limitations are presented. As a non-destructive technique, GPR is a powerful tool for the investigation of structures and structural members, roads, geological layers, archaeological sites and many more. The technology is based on electromagnetic radiation in the UHF/VHF range (10 MHz to 3 GHz). The choice of the frequency depends on the intended use, depth and size of the target and medium where the target is located. Joined with other testing methods (ultrasound method, dynamic methods with forced or ambient vibrations, electrical conductivity testing, etc.), GPR can provide a deep insight into the investigated object. However, like many other non-destructive methods, the choice of input parameters may affect the results. In this regard, a case study presented in this paper demonstrates not only different applications of GPR in civil engineering but also the determination (calibration) of one of those input parameters: the dielectric constant of glued laminated timber. The challenge here was not only to investigate the influence of the direction of measurements with regards to the direction of the fibers but also to acknowledge the contribution of the test antenna used during testing and dielectric constant calibration.

Evolving strategies in microbe identification—a comprehensive review of biochemical, MALDI-TOF MS and molecular testing methods

Abstract Detection and identification of microorganisms are the first steps to guide susceptibility testing and enable clinicians to confirm diseases and guide therapy. The faster the pathogen identification is determined, the quicker the appropriate treatment can be started. In the clinical microbiology laboratory, multiple methodologies can be used to identify organisms, such as traditional biochemical testing or more recent methods like MALDI TOF MS and nucleic acid detection/identification assays. Each of these techniques has advantages and limitations, and clinical laboratories need to determine which methodology is best suited to their particular setting in terms of clinical needs, availability of technical expertise and cost. This article presents a concise review of the history, utilization, advantages and limitations of the main methods used for identifying microorganisms in microbiology laboratories.

Calibration of the spherical tip radius of Rockwell hardness diamond indenters using a confocal laser scanning microscope

Abstract The precise form of an indenter is an essential part of hardness testing methods. It is therefore incumbent upon a user to ensure that the indenter geometry is calibrated before performing a hardness test. A geometric change of the tip radius by ±5 μm can cause a change of approximately 0.6 units of Rockwell hardness C scale (HRC) in a material with a hardness of 65 HRC. Keeping in mind that the measurement uncertainty is typically of the order of 0.3 HRC, it is critical to know the true value of the tip radius. Typically, tactile methods are used to determine the tip radius of a Rockwell hardness diamond indenter from the measured surface topography. Two main drawbacks of tactile measurements are the long duration of measurement and the limitation in capturing surface features of sizes smaller than the probe tip radius of 2 μm. Both could be overcome by using an optical 3D measurement. Confocal laser scanning microscopes (CLSM) allow a fast contactless 3D-mapping of the surface of Rockwell hardness diamond indenters and can be used to obtain geometric information such as the tip radius. The accuracy of these 3D measurements is still under question. Within this work, some of the influencing factors for fast 3D surface measurement are investigated. Using a CLSM with a 50x objective lens and a numerical aperture of 0.95, typical shape deviations of Rockwell diamond indenters are shown. Furthermore, an improved 3D based point cloud method for the evaluation of the indenter radius is presented. The aim of this paper is to explore the capabilities and limits of CLSM to obtain the 3D surface of a Rockwell hardness diamond indenter in order to calibrate the tip radius and compare their results with measurements from traceable stylus instruments.

Research progress on high-temperature properties of carbon fiber reinforced polymer composites for cables

Carbon fiber reinforced polymer composites (CFRP) cable has advantages of lightweight, high strength, and excellent durability, providing a new materials for cables and bringing out potential breakthrough in spanning capacity of structures. At present, CFRP cable has already been applied in some engineering bridges. The fire resistance performance of CFRP cable is critical for ensuring structure safety when suffering accidental fire disaster, and clarifying mechanical performance deterioration and failure mechanism of CFRP cable at elevated temperature is fundamental for research of its fire resistance. This paper summarizes current research progress on high-temperature properties of CFRP cable from two levels, including epoxy resin matrix and CFRP composites. Firstly, at resin matrix level, mechanical properties of epoxy resin and its degradation at elevated temperatures are reviewed and analysed, and potential ways to improve high-temperature performance of epoxy resin are suggested. Secondly, at CFRP composites level, high-temperature properties test methods and mechanical performance of CFRP composites in longitudinal direction and transverse direction at elevated temperatures are summarized and discussed. In addition, research shortage of high-temperature properties of CFRP cable is summarized, and corresponding further research is recommended.

A Novel Fractal Model for Contact Resistance Based on Axisymmetric Sinusoidal Asperity

In this paper, a novel fractal model for the contact resistance based on axisymmetric sinusoidal asperity is proposed, which focuses on the resistance characteristics of the rough interface at a microscopic scale. By introducing the unique geometric shape of axisymmetric sinusoidal asperity, and combining it with a three-dimensional fractal theory, the micro-morphology characteristics of the rough interface can be characterized more precisely. Subsequently, by conducting a theoretical analysis and numerically solving the deformation mechanisms of asperities on the rough interface, a refined model for contact resistance is constructed. This research comprehensively employs theoretical analysis, numerical simulation, and experimental testing methods to deeply explore the current transmission mechanisms during the contact process of the rough interface. The findings suggest that the proposed model is capable of precisely capturing the intricate interplay of various factors, including contact area, contact load, and material properties, with the contact resistance. Compared to the existing models, the presented model demonstrates significant advantages in terms of prediction accuracy and practicality. This research provides an important theoretical basis and design guidance for optimizing the electrical performance of the rough interface, which has great significance for engineering applications.

Lightning damage characteristics of Cf/SiC based on ultrasonic and multi‐nondestructive testing methods

AbstractAccording to the characteristics of the internal damage of the Cf/SiC composite material after the lightning strike, this article establishes a high‐energy ultrasonic excitation, reception, and high‐resolution ultrasonic testing model, achieving high‐energy and high‐resolution ultrasound C‐scan detection of Cf/SiC composite material samples after lightning strikes, and combining digital X‐ray and computed tomography methods for damage analysis. When the lightning energy is gradually increased, the lightning stratified damage will occur inside the sample, and the delamination damage area reaches the maximum value of 25182 mm2 at the lightning energy of S4. Subsequently, as the energy increases, significant needle‐like damage is generated at the needle‐stitched area inside the sample, and the area of delamination damage gradually decreases. When the energy continues to increase to the lightning strike energy of S6, as the energy increases, the number of needle‐like damage in the sample continues to grow, and penetrating injury appears at the needle suture site. At S8, the maximum number of needle‐like lightning damage occurred, with 53 damage points and a total volume of 256.86 mm3, respectively. Through comprehensive analysis, Cf/SiC has excellent resistance to lightning damage, but the needle‐stitched carbon fiber in the thickness direction significantly reduces its resistance to lightning penetration.

Inter-laboratory variation for urine albumin among laboratories in a Swedish external quality assessment scheme 2005–2023

IntroductionIncreased albuminuria is associated with elevated mortality. Urine albumin (U-ALB) above 20 mg/L or albumin-to-creatinine ratio (U-ACR) of 3 g/mol are indicative of moderately increased albuminuria. Due to limited standardization among U-ALB methods, diagnosis of increased albuminuria might prove difficult. Materials and methodsData from Equalis’s external quality assessment scheme for low U-ALB levels during 2005–2023 were categorized according to manufacturer and divided into central laboratory (CLAB) and point-of-care testing (POCT) methods. Manufacturer median values were compared to total group mean consensus values and manufacturer CV% was compared at different U-ALB levels. ResultsCLAB was generally closer to consensus values and had lower CV% than POCT at U-ALB levels around 20 mg/L. For CLAB, Roche methods were approximately equal to consensus U-ALB, Abbott 4 % above, and Siemens 5 % below. For POCT, HemoCue was 1 % below, Siemens 7 % above, and Abbott 8 % below. For U-Creatinine, all manufacturers generally had a good agreement differing on average by 1–4 % from consensus. ConclusionsAlthough U-ALB methods generally meet The National Kidney Disease Education Program (NKDEP) recommendations of method bias less than 13 % and imprecision less than 30 %, differences among manufacturers have increased over the last years, with 2023 showing the largest differences between methods. This highlights the need for guidelines for albuminuria and ACR to take method differences into consideration, but also for implementation of suitable urine reference materials.

FGTN: Fragment-based graph transformer network for predicting reproductive toxicity.

Reproductive toxicity is one of the important issues in chemical safety. Traditional laboratory testing methods are costly and time-consuming with raised ethical issues. Only a few in silico models have been reported to predict human reproductive toxicity, but none of them make full use of the topological information of compounds. In addition, most existing atom-based graph neural network methods focus on attributing model predictions to individual nodes or edges rather than chemically meaningful fragments or substructures. In current studies, we develop a novel fragment-based graph transformer network (FGTN) approach to generate the QSAR model of human reproductive toxicity by considering internal topological structure information of compounds. In the FGTN model, the compound is represented by a graph architecture using fragments to be nodes and bonds linking two fragments to be edges. A super molecule-level node is further proposed to connect all fragment nodes by undirected edges, obtaining global molecular features from fragment embeddings. The FGTN model achieved an accuracy (ACC) of 0.861 and an area under the receiver operating characteristic curve (AUC) value of 0.914 on nonredundant blind tests, outperforming traditional fingerprint-based machine learning models and atom-based GCN model. The FGTN model can attribute toxic predictions to fragments, generating specific structural alerts for the positive compound. Moreover, FGTN may also have the capability to distinguish various chemical isomers. We believe that FGTN can be used as a reliable and effective tool for human reproductive toxicity prediction in contribution to the advancement of chemical safety assessment.

Damage propagation and failure mechanism of single dome historical Masonry Mosque after February 6, 2023, Kahramanmaraş earthquake doublets (Mw = 7.7 and Mw = 7.6)

Many historical masonry mosques and minarets, including Milky Minaret Mosque and Ulu Mosque, which are very close to Ak Minaret Mosque in Malatya, suffered severe damage and collapsed after the Kahramanmaraş earthquake on February 6, 2023. Despite the settled loose soil properties and the presence of a small stream flow near the mosque, Ak Minaret Mosque, a historical masonry mosque with a single dome and square, remains operational even after the aforementioned earthquakes. Additionally, DEMA's strong ground motion station was out of service during both earthquakes. This situation raises questions about the mosque's ability to withstand the seismic load. The basic purpose of this paper is to investigate in detail the seismic performance, damage limits, the reason for unexpectedly less damage due to the earthquakes, the potential failure mode, and possible resisted earthquake loads of the historical Ak Minaret Mosque in Malatya, Türkiye. To achieve this goal, first, dynamic identification was performed on the mosque one year prior to the aforementioned earthquakes. Next, the material properties were determined using both non-destructive and destructive testing methods. Following the dynamic identification, a numerical model was generated by 3-D solid elements, and this 3-D model was calibrated using the dynamic identification tests. The mosque underwent both nonlinear static and nonlinear dynamic analyses. Nine seismic records were selected for the nonlinear dynamic analysis. Five of them were national, including even Kahramanmaraş earthquake records, and three of them were selected from an international database on the basis of fault characteristics and site classification. The analysis results indicate that Ak Minaret Mosque incurred less damage than expected during the Kahramanmaraş earthquakes. This could be due to soil improvement prior to the construction of Ak Minaret Mosque in 1573. Moreover, the effective restoration increased stiffness and maintained the mosque’s stability. Finally, the possible resisted PGA by the mosque was around 0.22 g.

Investigation on corrosion behaviour of metal oxide nanoparticles reinforced magnesium composites by salt spray and immersion corrosion test methods

ABSTRACT This study explores the increasing utilisation of lightweight materials, particularly magnesium (Mg) alloy, in sectors such as automobile, aerospace, and marine due to its notable advantages such as high strength-to-weight ratio, good castability, and excellent damping capacity. Despite these merits, Mg alloy faces challenges, notably in wear and corrosion resistance. The research focuses on enhancing the corrosion resistance of Mg alloy by incorporating Zinc Oxide (ZnO), Manganese Oxide (MnO), and Titanium Oxide (TiO2) nanoparticles. The alloy AZ91D and three nanocomposites, namely AZ91D + 1% ZnO, AZ91D + 1% MnO, and AZ91D + 1% TiO2, were manufactured using a stir squeeze casting technique combined with an ultrasonication process. To confirm the even distribution of reinforcement particles, Optical Microscope (OM), Scanning Electron Microscope (SEM) and High-Resolution Scanning Electron Microscope (HR-SEM) were employed. X-ray Diffraction (XRD) analysis revealed the presence of matrix and reinforcement material with intermetallic precipitates around the grain boundaries. Corrosion properties were assessed following ASTM standards and utilising a 3.5% NaCl concentration. The study found that AZ91D + 1% TiO2 nanocomposites exhibited superior corrosion resistance compared to the AZ91D alloy, showing a remarkable 77.78% and 69.89% improvement in corrosion behaviour under salt spray and immersion environments, respectively, after 48 hours.

Cognitive screening for children: Piloting a new battery of interactive games in 4- to 8-year-old children

Cognitive screening at the preschool age can be helpful in the early detection of possible difficulties before the start of school attendance as problems during schooling can have profound consequences. While interactive tools are still limited for the Czech population, tools used for cognitive screening at a younger age often consist of traditional pen-and-paper methods. Such examinations can be very demanding and time-consuming. This pilot study therefore focuses on the usability testing of a newly developed battery of interactive games used for the screening of selected cognitive functions in children aged four to eight in a less demanding and more attractive way. The battery consists of three interactive games testing (1) attention (selective attention), (2) executive functions (inhibitory control), (3) memory (episodic-like memory). The study sample included 24 participants of preschool or younger school age, ranging from 4 to 8 years old, girls = 12 (50%). The analyses also concentrated on the comparison of the newly designed screening tool with selected traditional test methods. The results suggest that the newly developed battery is feasible, and for children, it is entertaining and attractive. The designed cognitive battery is a promising tool for the screening of cognitive functions in younger school-age children.

Evaluation of the Utilization of Web-based Library Application Information Systems using Whitebox and Blackbox Testing Methods

The library information system is a computerized process for integrated data management. This research was conducted in the library located at SMAN 12 Bandung, Jl. Sekejati No. 36, Sukapura. The importance of performance measurement. The validity of implementation from the perspective of effectiveness and efficiency of web-based libraries is the main thing in the aim of managing library digitalization. This research was carried out using the Whitebox and Blackbox Testing integration method. The purpose of the research is to conduct an Information Technology Audit with the validity of measuring the effectiveness and efficiency of application functions. The research results show that the technical analysis of FlowGraph Whitebox is based on source code and flowcharts running on Cyclomatic Complexity which counts the number of nodes and edges in FlowGraph. Research implications support the assessment of the concrete validity of the method used. This can be seen from the research results that the performance of the Web-based Widyantara Library application at SMAN 12 Bandung is considered satisfactory with a good level of validity, this is proven by the test results using the white box testing method. Meanwhile, based on the analysis of the black box testing method on application functionality, the test results are said to be good with a validity percentage reaching 100%. Validity according to application design is proven by testing 10 application scenarios.

A comprehensive survey of UPPAAL‐assisted formal modeling and verification

AbstractUPPAAL is a formal modeling and verification tool based on timed automata, capable of effectively analyzing real‐time software and hardware systems. In this article, we investigate research on UPPAAL‐assisted formal modeling and verification. First, we propose four research questions considering tool characteristics, modeling methods, verification means and application domains. Then, the state‐of‐the‐art methods for model specification and verification in UPPAAL are discussed, involving model transformation, model repair, property specification, as well as verification and testing methods. Next, typical application cases of formal modeling and verification assisted by UPPAAL are analyzed, spanning across domains such as network protocol, multi‐agent system, cyber‐physical system, rail traffic and aerospace systems, cloud and edge computing systems, as well as biological and medical systems. Finally, we address the four proposed questions based on our survey and outline future research directions. By responding to these questions, we aim to provide summaries and insights into potential avenues for further exploration in this field.

Study on Analysing the Student Perspectives on Cultural and Social Diversity in Education

Education is presently required to create inclusive, supportive, and validating environments for education and experiences, while educational organizations continue to maintain students from many different kinds of cultural and socially diverse backgrounds. This research investigates how students engage and collaborate with diverse cultures and social environments to identify the key features influencing their social relationships and learning outcomes. To determine the possibilities and difficulties that students experience in a varied educational environment and make suggestions for the enhancements and assessment techniques for fostering a multicultural and diverse classroom. In this research, the details gathered from 350 students, and utilize 15 questionnaires related to cultural and social diversity in education that were developed, based on five variables, such as students attitudes towards diversity (SATD), impact on the learning environment (ILE), cultural awareness (CA), perception of cultural and social diversity (PCSD), and social interactions (SI). The Wilcoxon-Mann-Whitney test and inferential statistics analysis methods are evaluated through the SPSS software. From both analyses, the variable PCSD performance is higher than other four variables in the field of student perception of social and cultural diversity in education.

Study on Analysing the Student Perspectives on Cultural and Social Diversity in Education

Education is presently required to create inclusive, supportive, and validating environments for education and experiences, while educational organizations continue to maintain students from many different kinds of cultural and socially diverse backgrounds. This research investigates how students engage and collaborate with diverse cultures and social environments to identify the key features influencing their social relationships and learning outcomes. To determine the possibilities and difficulties that students experience in a varied educational environment and make suggestions for the enhancements and assessment techniques for fostering a multicultural and diverse classroom. In this research, the details gathered from 350 students, and utilize 15 questionnaires related to cultural and social diversity in education that were developed, based on five variables, such as students attitudes towards diversity (SATD), impact on the learning environment (ILE), cultural awareness (CA), perception of cultural and social diversity (PCSD), and social interactions (SI). The Wilcoxon-Mann-Whitney test and inferential statistics analysis methods are evaluated through the SPSS software. From both analyses, the variable PCSD performance is higher than other four variables in the field of student perception of social and cultural diversity in education.

BIM and orthogonal test methods to optimize the energy consumption of green buildings

The construction industry’s rapid growth significantly impacts energy consumption and environmental health. It is crucial to develop optimization strategies to enhance green building energy efficiency and encompass comprehensive analysis methods. This study aims to introduce and validate a novel framework for optimizing energy efficiency design in green buildings by integrating Building Information Modeling (BIM) technology, Life Cycle Cost (LCC) analysis, and orthogonal testing methods, focusing on enhancing energy efficiency and reducing life cycle costs. The optimization parameters for the building envelope are identified by analyzing energy consumption components and key green building factors. The orthogonal testing method was applied to streamline design options. Building Energy Consumption Simulation (BECS) software and LCC analysis tools were employed to calculate each optimized option’s total annual energy consumption and the current life cycle costs. Using the efficiency coefficient method, each optimization scheme’s energy consumption and economic indicators were thoroughly analyzed. The framework’s validity and applicability were confirmed through an empirical analysis of a campus green building case in Fujian Province, demonstrating that the optimized framework could reduce energy consumption by 4.85 kWh/m2 per year and lower costs by 38.89 Yuan/m2 compared to the reference building. The case study highlights the framework’s significant benefits in enhancing environmental performance and economic gains. The results provide critical parameter selection and offer scientific and technological support for the design of building energy efficiency, promoting optimization techniques and sustainable development within the construction industry.