Uniform Test Method Research Articles

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.

Neural Network-Based Estimation of Flexural Performance for Polymer Permeable Concrete

Pervious concrete is increasingly used to reduce runoff water and improve water quality near pavements and parking lots, but highway pavement structures cannot use it due to its high porosity and reduced strength. To address the issue of lower flexural strength in permeable concrete, this study designs and conducts 11 different tests with varying mix ratios. The objective is to ensure that the resulting concrete satisfies both permeability and compression resistance requirements. The uniform test method is employed to measure the flexural strength of the concrete after a period of 28 days. This study employs neural networks to analyze the flexural performance of polymer permeable concrete by considering various input factors such as cement consumption, water consumption, STA (4.75 to 9.5 mm stones), STB (9.5 to 16 mm stones), VAE (vinyl acetate-ethylene) polymer content, and SAP polymer content. The objective is to optimize the mix proportion of polymer permeable concrete and identify a suitable ratio that satisfies the requirements of pavement structural flexural performance.

Biological Durability of Wood–Polymer Composites—The Role of Moisture and Aging

Knowledge about the resistance of wood-polymer composites (WPCs) to biological attack is of high importance for purpose-oriented use in outdoor applications. To gain this knowledge, uniform test methods are essential. EN 15534-1 (2018) provides a general framework, including the recommendation of applying a pre-weathering procedure before the biological laboratory tests. However, the procedure's manner is not specified, and its necessity assumes that a durability test without such pre-weathering will not produce the structural changes that occur during outdoor use. To verify this assumption, this study examined the influence of natural, ground-level pre-weathering on the material properties of different WPC variants, which were tested at intervals of six months in four durability tests under laboratory conditions in accordance with EN 15534-1 (2018). Weathering factors were calculated from determined characteristic values such as mass loss, and loss in moduli of elasticity (MOE) and rupture (MOR). The weathering factors based on mechanical properties tended to decrease with increasing weathering duration. The expected negative influence of pre-weathering on these material properties was thus not confirmed. The weathering factors based on mass loss were subject to high variation. No significant effect of pre-weathering on mass loss due to fungal attack became evident. Overall, the necessity of a pre-weathering step in biological durability tests shall be questioned based on the presented results.

Efficient preparation and characterization of graphene based on ball milling

Graphene has a unique two-dimensional crystal structure and excellent physical and chemical properties. It is one of the new strategic materials developed by countries around the world in the 21st century. In recent years, the method of preparing graphene by mechanical stripping is becoming mature, including oxidation reduction method, mechanical stripping method, SiC epitaxial growth method, chemical vapor deposition method, etc. Based on the ball milling method, graphene is prepared in this study using a uniform design test method, scaled graphite as the raw material, and metallic aluminum as the grinding aid while considering the influence of ball ratio, grinding time, and rotation rate. A mathematical model was established based on partial least squares regression analysis and stepwise regression analysis. The best experimental scheme was obtained through the selection and optimization of the mathematical model, and the process of efficiently preparing graphene in the laboratory was explored. The prepared products were characterized by X-ray diffractometer, automatic specific surface area and porosity analyzer, and laser confocal Raman spectrometer. The results indicate that using aluminum powder as a grinding aid can significantly improve the efficiency of ball milling, the specific surface area of graphene produced is 542.598 m2/g, with the number of layers ranging from 2 to 5 layers. It is proved that the proposed graphene preparation method can obtain graphene with better quality. The study's findings serve as a guide for the production of graphene.

Evaluation of safety-related performance of wearable lower limb exoskeleton robot (WLLER): A systematic review

Wearable lower limb exoskeleton robots (WLLER) have broad development prospects in the military, industrial and medical fields. The intelligent device comes into intimate contact with the human body, and its safety is an essential factor that developers must consider. With the increasing research on the safety of WLLER, its safety test methods and indicators should gradually improve. By examining current test methods and indicators, this study aims to mobilize this information and summarize the most recent safety research. The safety-related studies reviewed in this paper are not limited to evaluating subjects in clinical trials but are concerned with extensive safety research. The focus of our analysis is the test performance indicators. Some functional evaluation indicators are also summarized to explore a broader and more applicable approach on the safety metrics. We found that, in general, most researchers pay attention to the power-assisting performance of WLLER, but the stability and comfort have been largely ignored. At the same time, our analysis also reveals that although there are a wide variety of existing evaluation indicators, uniform and standard test methods and indicators for safety testing of WLLER are still deficient. Based on these results, we identified and discussed several promising research directions that may help the community to attain a widely accepted test method that can objectively evaluate the safety of WLLER.

REDA: A New Methodology to Validate Sensor Systems for Person Detection under Variable Environmental Conditions

Perception of the environment by sensor systems in variable environmental conditions is very complex due to the interference influences. In the field of autonomous machines or autonomous vehicles, environmental conditions play a decisive role in safe person detection. A uniform test and validation method can support the manufacturers of sensor systems during development and simultaneously provide proof of functionality. The authors have developed a concept of a novel test method, “REDA”, for this purpose. In this article, the concept is applied and measurement data are presented. The results show the versatile potential of this test method, through the manifold interpretation options of the measurement data. Using this method, the strengths and weaknesses of sensor systems have been identified with an unprecedented level of detail, flexibility, and variance to test and compare the detection capability of sensor systems. The comparison was possible regardless of the measuring principle of the sensor system used. Sensor systems have been tested and compared with each other with regard to the influence of environmental conditions themselves. The first results presented highlight the potential of the new test method. For future applications, the test method offers possibilities to test and compare manifold sensing principles, sensor system parameters, or evaluation algorithms, including, e.g., artificial intelligence.

The analysis and evaluation of direct air capture adsorbents on the material characterization level

Direct air capture (DAC) of carbon dioxide has been identified as a necessary negative emission technology to limit global temperature rise to 2 °C by 2100. With the research progress in DAC, an increasing number of adsorbents have been developed and investigated. This brings about the questions that what makes good adsorbents for DAC and how to characterize and compare them with different natures. In this paper, the performance parameters of state-of-art DAC adsorbents were investigated, and it is found that because of the varying test conditions, the comparison of some parameters appears to be difficult. Therefore, it is recommended that for each performance parameter, it is best to determine relatively uniform test methods. To this end, this paper selected five benchmark adsorbents and used a set of test methods as a demonstration. Key performance parameters of the adsorbents were measured. On this basis, by comparing the results with that in existing research, the characteristics of different types of adsorbents were summarized and suggestions for future material development were provided.

A methodology for determining precision and accuracy of the measurement of position and orientation of implant interfaces for multi-implant structures.

The digital workflow relies on many technologies such as intra-oral scanners, CBCT, guided surgery, robotics, and photogrammetry. Efficient and uniform testing methods are required for assessing the precision and accuracy of these systems to select the right technology for the right task. The method uses values that are directly derived from the measurement of the implant position and orientation in the scanning software, photogrammetry software, and/or the CAD software. It was developed over a decade ago for desktop scanners and successfully used for photogrammetry, intra-oral scanners, and CBCT. The components which can be evaluated are the positional precision and accuracy in the implant plane, in the implant axis, and the direction/angle of the implant axis. The methodology can also be used to assess the impact of errors in the implant axis on the fit of the structure. Many other values such as cross arch distances can be computed. Applying this methodology to several devices brought to light the huge differences in their behavior. This has a major impact on how the devices need to be tested. The precision both in vitro and in vivo can be determined easily. This led to important conclusions relating to the validity of in vitro tests. The methodology is providing an efficient and uniform method for the analysis of the precision and accuracy of multi-implant structures. It has brought to light the strengths and weaknesses of different technologies not known before.

Conceptual design, optimization and thermodynamic analysis of a CO2 capture process based on Rectisol

Reducing CO2 emission is particularly important for environmental protection. Much absorbed CO2 in the conventional Rectisol process is discharged as tail gas due to the lacked attention to the by-product CO2. In this paper, a novel CO2 capture process, which is improved from the conventional Rectisol process, is proposed to reduce the emission of CO2. The revised CPA model shows a good performance and is used for the process simulation. Spin-up method is employed to optimize the CO2 capture process and uniform test method is used to further verify the optimization procedure. The results show that compared with the conventional Rectisol process, the system exergy consumption increases by 17.81%, but the exergy consumption per unit CO2 is 64.57% lower in the optimized CO2 capture process. The parameters in terms of the first-stage temperature Tfi, second-stage pressure Pse, and third-stage temperature Tth are analyzed, which show similar influence rules for the CO2 capture process. In addition, exergy distributions about the Rectisol process and the optimized CO2 capture process are investigated for the further thermodynamic analysis. This paper may guide for the improvement and optimization of more profound CO2 capture process.

Research on Braking in a Turn and Parameter Optimization of Centre-axle trailer combination Based on TruckSim

This paper uses TruckSim dynamics simulation software to build a non-linear model of a center-axle trailer combination, conducts a braking in a turn simulation to study its braking in a turn stability, and a straight-line braking test was carried out on the train through the built-up centre-axle trailer combination braking performance test system, and the reliability of the simulation model was ensured by comparing the test and simulation results. In order to improve the braking performance of the train, a comprehensive evaluation index for evaluating the braking performance of the train is proposed by taking the structural parameters of the train as the optimization variable. The uniform test method is used to optimize the design of the variables, and the braking in a turn is performed on the high adhesion road. Simulation and analysis results show that the optimization reduces the probability of brake folding and improves braking stability.

Blade number effect on the optimal energy efficiency for a modified Savonius rotor

In this paper, the effect of the number of blades on the optimal energy utilisation efficiency for a modified Savonius rotor with rotor diameter of 4 m is investigated by computational fluid dynamics simulation using a uniform test method. The appropriate computational domain of a numerical model is determined by first analysing the relative error of the outlet wind velocity on the outflow boundary of the domain. Taking the rotor rotation speed, the blade width and blade installation angle of the modified Savonius rotor as three key factors, it obtains the optimal energy utilisation efficiencies for the modified Savonius rotors with eight, nine and ten blades by transient numerical simulations under the condition of wind velocity of 8 m/s. The sliding mesh and the Piso (pressure implicit with splitting of operators) scheme are utilised in Fluent software simultaneously. The results demonstrate that the optimum wind energy utilisation efficiency rises and the corresponding blade width decreases with the number of blades.

ECC Design Based on Uniform Design Test Method and Alternating Conditional Expectation

Engineered cementitious composites (ECC) have higher ultimate tensile strains than normal concrete. The mechanical properties of ECC strongly depend on raw materials and the mix proportions. The uniform design test method and alternating conditional expectation, which is a nonparametric regression analysis method, were used to design the ECC mix proportion. According to the regression analysis, the optimized W/B, S/B, and F/B ranges could be obtained as 0.35–0.42, 0.25–0.3, and 0.02, respectively. The tested proportions for validation were randomly adopted within the range of W/B, S/B, and F/B. The uniaxial compression, tension, and four-point bending tests were conducted to verify the material behaviour of the designed ECC. Results showed that all the specimens had large ultimate tensile strains and high fracture energy capacities, and strain hardening was also observed. The fibers were found to be uniformly distributed in the specimens by using a scanning electron microscope. This paper may provide theoretical and practical guidance for the ECC and other cement-based material mix proportion design.

Variation of energy utilization efficiency with respect to inlet wind speed for eight-blade modified Savonius rotor by CFD approach

ABSTRACTThis study investigates the optimal wind utilization efficiencies of eight-blade modified Savonius vertical axis wind turbine as a function of blade width, blade installation, and rotor speed under various inlet wind speeds. All the simulations are designed based on the uniform test method and conducted by computational fluid dynamics (CFD) numerical calculation. Sliding mesh approach and k-ω SST turbulence modeling are employed in the processing. Results indicate that the optimal wind energy utilization efficiency and rotor speed increase almost linearly with the inlet wind speed for the modified eight-blade Savonius rotor with the diameter of 4 m in the range of wind speed from 6m/s to 10 m/s, while the changes of the optimal blade width and installation angle are non-monotonous.

Система взаимного признания данных ОЭСР как инструмент снижения барьеров для экспорта (OECD Mutual Recognition System as a Tool to Reduce Export Barriers)

Russian Abstract: В работе был провден анализ выгод и рисков участия России в системе взаимного признания данных неклинических лабораторных исследований ОЭСР, которая базируется на согласованных на международном уровне принципах надлежащих лабораторных практик и единых методах испытаний и позволяет избежать проведения повторного тестирования химических веществ. В результате исследования авторами сформулированы предложения для оптимального сценария присоединения России к системе взаимного признания данных неклинических лабораторных исследований ОЭСР, в т.ч. с учетом членства России в ЕАЭС. English Abstract: The paper analyzed the benefits and risks of Russia's participation in the mutual recognition system of OECD non-clinical laboratory research, which is based on internationally agreed principles of good laboratory practices and uniform test methods and avoids re-testing of chemicals. As a result of the study, the authors formulated proposals for the optimal scenario of Russia's accession to the system of mutual recognition of OECD non-clinical laboratory research data, including taking into account Russia's membership in the EAEU.

Uniform Test Method Optimum Design for Drag-Type Modified Savonius VAWTs by CFD Numerical Simulation

This paper reports the results of optimizing design of the drag-type modified Savonius VAWTs with 4, 5 and 6 blades by using uniform test method. The optimal design is performed in the light of wind energy utilization rate as the goal function and conducted by numerical simulation for drag-type modified Savonius VAWTs with 4, 5 and 6 blades; the FLUENT software, sliding grid technology and PISO algorithm are employed in the process. In the optimization, the blade width, the blade installation angle and the rotation rate of windmill are taken as the basic parameters. The results indicated that the optimal wind energy utilization rate is $${C}_{\mathrm{p}} = 27.140\%$$ for the 4-blade turbine at the blade width $$d = 0.882\,\hbox {m}$$ , blade installation angle $$\theta = 24.895^{\circ }$$ and the windmill rotation rate $$\omega =17.206 \,\hbox {r}/\hbox {min}$$ ; the optimal wind energy utilization rate is $${C}_{\mathrm{p}}=28.493\%$$ for the 5-blade turbine at $$d = 0.803\,\hbox {m}$$ , $$\theta =17.425^{\circ }$$ and $$\omega =16.265\, \hbox {r}/\hbox {min}$$ ; the optimal wind energy utilization rate is $${C}_{\mathrm{p}}= 30.564\%$$ for the 6-blade turbine at $$d = 0.681\,\hbox {m}$$ , $$\theta = 21.650^{\circ }$$ , $$\omega = 18.369\, \hbox {r}/\hbox {min}$$ .

Test Technology Research on Missile Infrared System Range

Today, all kinds of guided missiles almost have equipped infrared reconnaissance or guided system, infrared range is important elements to influencing hit rate of guided missile and indispensably appraised performance index in appraisal test. In this paper, for adequately appraising missile infrared system range, elements including temperature difference between object and background, relative humidity, air visibility that influence infrared system performance are deep analysed, test project is optimized based on uniform design method, real equipment and simulation test methods are put forward, test results of one missile infrared system validates science and rationality this test method.

Autism spectrum disorder and impaired joint attention: A review of joint attention research from the past decade

Individuals with autism spectrum disorder (ASD) have been found to have impaired joint attention (JA), which is considered key for learning social communication. This study reviewed the JA literature from the past decade to explore the generality of the deficit and looked at the JA assessment methods to see whether children's interests and preferences that may impact the results had been taken into account. While this review found evidence of impaired JA, it also found evidence of intact JA skills at the individual and group levels, indicating a non-uniform impairment of JA. A largely homogeneous assessment methodology within the published research was discovered, and no study reported using children's interests to create the assessment situation. The finding of JA skill variation between and within groups and individuals suggests that JA is within the scope of the learning capabilities of individuals with ASD. Due to the JA skill variation, we suggest that reporting individual data among group data to be an important aspect. We also propose that the uniform testing methods for JA might not be bringing to the surface all the capabilities held by individuals with ASD, and hence, individualized assessments based on preferences are suggested.

An iterative approach to measurement of oblique acoustic absorption coefficient in three-dimensions

The measurement of oblique acoustic absorption coefficient remains an ill-defined test. Unlike Kundt's tube (ASTM C384 and E1050) and Sabine room measurements (ASTM C423), there is no uniform test method or standard to follow. In-situ or specific application based testing is the industry norm for arbitrary angular absorption coefficient measurement. An iterative approach has been developed for a free/free/free/free panel in an anechoic chamber. Using numerical model predictions of the acoustic field, microphone measurement data are updated to account for a multitude of acoustic phenomena including diffraction from the panel. This method provides a quick measurement option that is flexible and transportable for many applications.

Time-domain simulation and waveform reconstruction for shielding effectiveness of materials against electromagnetic pulse

Shielding effectiveness (SE) of materials of current testing standards is often carried out by using continuous-wave measurement and amplitude-frequency characteristics curve is used to characterize the results. However, with in-depth study of high-power electromagnetic pulse (EMP) interference, it was discovered that only by frequency-domain SE of materials cannot be completely characterized by shielding performance of time-domain pulsed-field. And there is no uniform testing methods and standards of SE of materials against EMP. In this paper, the method of minimum phase transfer function is used to reconstruct shielded time-domain waveform based on the analysis of the waveform reconstruction method. Pulse of plane waves through an infinite planar material is simulated by using CST simulation software. The reconstructed waveform and simulation waveform is compared. The results show that the waveform reconstruction method based on the minimum phase can be well estimated EMP waveform through the infinite planar materials.

Photocatalytic roads: from lab tests to real scale applications

This paper gives an overview of our research on photocatalytic concrete, which exhibits air purifying properties. Under the action of sunlight, a catalyst present at the surface of the material is activated, enabling degradation of pollutants from the surroundings and transformation to less harmful products. It is a promising technique to reduce a number of air contaminants, especially at sites with a high level of pollution: highly trafficked canyon streets, road tunnels, etc. In addition, the combination with cement offers some synergistic advantages, as the reaction products can be adsorbed at the surface and subsequently washed away by rain. However, the great potential of this emerging technology is hampered by the lack of uniform testing methods at European level to evaluate the photocatalytic activity. Laboratory research is undertaken at BRRC to compare existing methods and draw up recommendations for future standards. Furthermore, translation of lab testing towards results in situ remains critical to demonstrate the effectiveness on larger scale. In this perspective, several trial applications have recently been initiated in Belgium to asses the “real life” behavior. The paper gives a short overview of the photocatalytic principle and the application in concrete, as well as some main results of the laboratory research recognizing the important parameters that come into play. In addition, the implementation efforts of some recent realizations in Belgium will be presented. Already some very promising results towards air purification have been obtained. Nevertheless, further validation, also with modeling, is necessary to extrapolate the findings and enable a judicial implementation of photocatalytic road materials across the globe.