5.2: Durability test methods on E‐paper and flexible displays

Durability evaluation of adhesive tapes for building applications

The durability of chemically treated subgrade soils is important for pavement design life, and it is a major concern for transportation and defense agencies. Stabilized soil layers should retain strength and stiffness properties under wetting–drying-related durability cycles and moisture exposure. Many durability test methods, including wetting and drying, tube suction, and Engineer Research and Development Center’s wet-test methods, have been developed and used in several stabilization studies in the past. It is important to study and determine how these methods address the long-term performance of chemically stabilized soils with a focus on stabilizer permanency. Therefore, this research study conducted a comprehensive laboratory investigation using all three methods to assess the durability of stabilized soils as per the US Department of Defense protocols. Three types of soils, silty sand, clayey sand, and high-plasticity clay, and three types of stabilizers, vinyl acetate-ethylene (VAE) copolymer, Portland cement type I, and hydrated lime, were considered in this study. Silty sand, clayey sand, and high-plasticity clay soils were treated with VAE copolymer, cement, and lime, respectively. Results of cement-stabilized soil showed that it is unsusceptible to moisture fluctuations, whereas VAE-stabilized soil indicated its higher susceptibility to moisture variations. Both the ASTM wet–dry (W-D) test and tube suction test methods revealed that lime-treated clayey soil is moisture-susceptible. All three methods showed similar findings, with good agreement existing between tube suction and ASTM W-D tests for all combinations of soils and stabilizers considered in this study.

In order to reduce the air pollution caused by automobile exhaust emissions, the proton exchange membrane fuel cell (PEMFC) is more and more widely used in automobile field. While the durability is an important reason hindering the development of fuel cell. In order to popularize the use of PEMFC, it is important to improve durability and prolong service life of PEMFC. Based on the working mechanism of PEMFC and the analysis of durability test conditions, methods and health indicators, this paper compares the durability test data of fuel cells under three different working conditions, analyzes the influence of different working conditions on performance degradation of fuel cells, and discusses the reasons for different performance degradation laws. Finally, the advantages and disadvantages of fuel cell life prediction algorithms are summarized.

HighlightsSpray deposition and distribution evaluations of UAVs were conducted.Spray distributions by the ISO and the Japanese protocol showed similar trends.The Japanese test protocol is useful as an evaluation method.A great benefit is its consideration of UAV-specific downwash and crosswinds.Abstract. For this study, evaluations of spray deposition and distribution on industrial unmanned helicopters and multi-rotor UAVs were conducted, respectively, according to the Japanese convention test protocol for UAVs and the test protocol for ground boom sprayers specified in ISO 24253 part 1. Using both the Japanese conventional protocol and the ISO 24253 protocol, spraying was conducted with 8 L per hectare with commercial UAVs. The amounts of tracer captured by collectors placed on the ground surface were measured and converted to the spray application rate per area. Results found for spray distribution by the ISO protocol exhibited similar trends to those obtained using the Japanese protocol. Results obtained from comparing the spray depositions of both test protocols indicated coefficients of determination R2 of the spray deposition measured values as 0.64 and 0.85, respectively, for helicopters and multi-rotors. Under the Japanese protocol, droplets on each of the five planes of the cubic collector were examined. More than 40% of the total droplets were observed on vertical planes because of downwash from UAV rotors, despite the crosswind effect during spraying. Therefore, one reason for differences in deposition values between these test methods was that the Japanese test protocol was able to capture droplets from the lateral direction with the cubic collector, which could not be captured using the ISO test. The Japanese test protocol, which measures the amount of adhesion using cubic collectors, is a useful and promising evaluation method that takes into account the UAV-specific downwash and crosswind effects. Keywords: ISO 24253 part 1, Japanese convention test protocol for UAVs, spray deposition and distribution, UAV pesticide application.

The membrane electrode assembly (MEA) durability test protocols proposed by FCCJ, USFCC and DOE were compared in their deterioration behavior of performances and materials. These MEA durability tests for polymer electrolyte fuel cells were performed using JARI's standard single cell. In the carbon support corrosion test protocols, carbon decomposition (oxidation), collapsing of the porous structure of the carbon support, and agglomeration and dropout of the platinum (Pt) catalyst were observed. A proper fast evaluation can be done by the FCCJ protocol because of the highest applied voltage. In the Pt catalyst stability test protocols, both Pt particle growth and also carbon oxidation were observed in the Pt/C catalyst used in this study. It was found that the carbon oxidation rate was the lowest in the DOE protocol. In the membrane durability test protocols, decomposed fluorine F- and thinning of membrane were observed. Tests results suggest that the FCCJ protocol (using air, without pressure difference between anode and cathode) was the best at early stage evaluation.

A review of durability test protocols of the proton exchange membrane fuel cells for vehicle

There are over five dozen field applied liquid rehabilitation pipeline coatings in the US market with limited performance data available from suppliers. Although there are many test methods in the literature for evaluation of pipe coatings, there are no commonly accepted test protocol and acceptance criteria for selecting coatings. End users have a great difficulty to select appropriate coatings to protect their buried pipelines. Also, no convincing technical data can be obtained from suppliers to help us determine the upper service temperature for a coating. Some coatings have long dry-to-touch time and attract insects to crawl over the wet paints at night to produce holidays which require repairing the next day. The purpose of this work is to develop a test protocol considering both application convenience and good performance and to select the coatings to rehabilitate our pipelines. The attributes for application convenience are environmental friendliness, pot life, dry-to-touch time, backfill time, etc. The coating performance includes cathodic disbondment, penetration, impact, and abrasion resistance. The acceptance criteria have also been developed to make the selection. Test methods to determine upper service temperature for the coatings were also developed. This test protocol is using standard ASTM test methods with slight modifications and can be used by both coating suppliers and end users.

Pt-nanoparticles activated porous carbon composite catalysts are widely used in PEMFC applications. The instability of these catalysts in harsh fuel cell working conditions is the main problem hindering the large-scale application of the fuel cell technology in commercial and energy recuperation systems [1]. Hierarchical microporous-mesoporous carbon supports C(Mo2C) were prepared from molybdenum carbide using high temperature chlorination method at different synthesis temperatures from 600 °C to 1000 °C. The Pt-nanoparticles were deposited onto the carbon support using the NaHB4method [2,3]. The X-ray diffraction, low temperature nitrogen sorption, thermogravimetric analysis (TGA) and high-resolution scanning electron microscopy (HRSEM) methods were used to characterize the catalysts materials. The medium size of the Pt-nanoparticles deposited was 4.5±0.6 nm. Corrosion of the Pt-C(Mo2C) catalysts were evaluated using an accelerated durability test (ADT) method (in oxygen (99.999%, AGA) saturated 0.5 M H2SO4 aqueous solution, from 0.58 V to 0.98 V vs SHE, at potential scan rate 50 mV s−1) [4]. The oxygen electroreduction reaction kinetics and the value of electrochemically active surface area (ECA) of the catalysts were determined after 10, 100, 1000, 3000, 10 000, 20 000 and 30 000 cycles. Electrochemical impedance spectra were obtained at 0.9 V vs SHE within ac frequencies from 0.01 to 10 000 Hz to determine the changes of the electrolyte resistance and capacitance values during the ADT. The results show that only 20% decrease in electrode capacitance and 15% increases in series resistance takes place during 30,000 potential cycles. The values of ECA were estimated in the solution saturated with nitrogen (99.999%, AGA) using the cyclic voltammetry at different potential scan rates from 30 to 1000 mV s−1. The rotating disc electrode method was used to evaluate the oxygen electroreduction kinetics in solution saturated with oxygen at rotation rate 1600 rev min−1 and at potential scan rate 20 mV s−1within the region of potentials from 1.03 V to 0.03 V vs SHE. Based on the cyclic voltammetry and rotating disk electrode data the main decrease in ECA took place during the first 1000 cycles and thereafter the ECA value stabilized. The half wave potential values depend weakly on the number of cycles (up to 30,000) measured. The content of Pt in the catalyst was determined before and after the ADT using the electrochemical dissolution of platinum from the electrode in 6 M HCl solution. The average weight percentage of Pt in different catalyst materials was 71.8±1.7. The content of Pt in the catalysts before the ADT was in a good agreement with the TGA data.

A number of pesticide application technologies offer the potential to reduce spray drift from pesticide applications. However, limited information exists on the effectiveness of these technologies in reducing spray drift. Working with a stakeholder technical panel under EPA’s Environmental Technology Council, the Office of Pesticide Programs in EPA has developed and is in the process of validating a testing protocol to verify the effectiveness of drift reduction technologies (DRTs). The DRT testing protocol was adapted from standard test methods and regulatory methods used in other countries and describes the testing approach that will be used to generate high-quality, peer-reviewed data for DRTs, including test design and quality assurance aspects. Both low-speed and high-speed wind tunnel tests were completed using a reference nozzle and two test nozzles to evaluate the performance of the generic DRT testing protocol. By Summer 2010, EPA anticipates to finalize this testing protocol based on the test results performed by EPA and other stakeholders. As a next step, EPA intends to encourage equipment manufacturers to voluntarily use the protocol for testing their equipment. Tested technologies that are proven to significantly reduce spray drift may be considered for addition to pesticide product labels by pesticide registrants and by EPA in its risk assessment and management decisions for the registration of new pesticide and uses and registration review (reevaluation) of currently registered pesticides. Pesticide product labels citing the use of DRTs could have reduced restrictions for applications, provide applicators with greater flexibility, and result in less off-target pesticide deposition. This paper will provide an update of EPA’s efforts to validate the DRT testing protocol and discuss future plans for using a validated protocol in evaluating DRTs in an effort to reduce load from unintended spray drift of pesticides in the environment.

Under the auspices of ASTM Committee C01 on Cement, an interlaboratory study was conducted to determine precision and bias for bond-wrench testing carried out under the requirements of ASTM Specification for Mortar Cement (C 1329-98) and ASTM Test Methods for Evaluating Masonry Bond Strength (C1357-98a). Another paper at this symposium [1] describes in detail that interlaboratory study and the results of the corresponding analysis for precision and bias. One objective of that analysis is to determine a “repeatability limit,” r, and a “reproducibility limit,” R. The repeatability limit quantifies what is commonly called the “within-lab variability,” whereas the reproducibility limit quantifies what is commonly called the “lab-to-lab variability.” The goal of this paper is to take the data from that interlaboratory study and analyze in more detail the possible sources of within-lab variability, including batch-to-batch, prism-to-prism, and bond-to-bond variability. This detailed analysis enables the rediction of variability for different test protocols (that is, with different numbers of batches, prisms and bonds). It also enables the prediction of how much time each test protocol would take to complete, which is directly related to the cost of testing. Finally, by comparing the probable variability and probable cost of each test protocol, it is possible to identify those test protocols that are most cost-effective for routine comparison of two mortars. This type of analysis is also useful in setting up other interlaboratory studies and interpreting their results.

This report presents recommended changes to coal fly ash specifications and test protocols contained in AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing (AASHTO M 295). These changes include modifications to the test methods currently specified for evaluating acceptability of fly ash for use in highway concrete as well as the introduction of new test methods for enhancing such evaluations. The modified specifications and test protocols will guide materials engineers and fly ash producers in evaluating fly ash and assuring that highway concrete is enhanced, and not deleteriously affected, by replacing a portion of the cement in the concrete mixture with fly ash. The information contained in the report will be of immediate interest to state materials engineers and others involved in specifying and evaluating concrete mixtures for use in highway pavements and structures.

This study compared the effectiveness of five commercially available cooling vests using three distinct thermal manikin test protocols. In addition, the constraints associated with each test protocol were elucidated, facilitating the identification of suitable evaluation methods for the different cooling vests. The cooling performances of the vests were evaluated using three thermal manikin test scenarios, incorporating the adaptations from Ciuha et al. (Ergonomics 64:625–639, 2021) and ASTM F2371-16, along with a modified protocol simulating the hot and humid weather in a South Korean summer. The results revealed substantial variations in the cooling performance across different test protocols, highlighting the importance of carefully selecting thermal manikin test methods. Moreover, the specific cooling vests exhibited immeasurable performance in certain test methods, which presents the limitations inherent in each testing scenario. For example, when evaluated with a non-sweating thermal manikin, the air-cooling vests exhibited the worst cooling performance, showing an average cooling rate of 1.0 W and cooling durations of five minutes. In contrast, the same vests demonstrated superior performance when assessed using the ASTM F2371-16 method, revealing an effective cooling rate of 114.8 W and sustained cooling durations exceeding eight hours. These results emphasize the lack of a one-size-fits-all evaluation method for cooling vests and the need for accessible guidelines to inform decision-makers aiming to enhance workplace safety and comfort.

The application of advanced engineering in tennis has seen vast changes in playing styles, racket materials and racket design. Although previous researchers have investigated the effects of racket properties during and post ball-racket impacts, the studies focused on limited variation within racket properties. As regulators of the game, the International Tennis Federation monitor racket performance, however, standard laboratory test methods do not exist. The establishment of appropriate testing standards would further the understanding of the effect of racket properties, or racket property combinations, whilst reducing discrepancies between studies. This work aims to identify racket properties resulting in distinct behavioural characteristics through the development of a test protocol accurately simulating different forehand conditions found within the field of play. Classification of the raw player testing data, previously collected from the 2006 Wimbledon Qualifying tournament, identified the characteristics of three specific forehand shots used within the field of play. The forehand shots were identified as either topspin or slice, each possessing different defining characteristics. The results from the player shot classification, five impact positions varying along the longitudinal and transverse axis, and a restrictive torque value representative of hand grip were used in the development of a laboratory test protocol capable of realistically and accurately simulating different forehand shots. Using the developed test protocol for a typical topspin and slice forehand, a total of 39 rackets of varying properties and property combinations, were repeatedly impacted at the relative impact positions. A three-dimensional analysis, through the use of two Phantom High-Speed video cameras, recorded the experimental outputs within a fully calibrated control volume. Reducing the complexity of the data, the experimental outputs were interpreted using clustering techniques, identifying clusters of rackets sharing similar behavioural characteristics. A total of four clusters of distinct behavioural characteristics were identified for both the topspin and slice forehand. Analysis of these clusters revealed that rackets of diverse property combinations can produce similar behavioural characteristics, indicating the importance of varying racket property combinations in this area of research. The relationships between the behavioural clusters and subsequent racket properties were identified using multinomial logistic regression. (MNLR). Investigations revealed a complex dynamic relationship between racket properties and racket behaviour, such that racket behaviour, or performance, is dependent on its physical properties as both individual and interacting entities and are specific to shot type. Therefore, to gain a complete understanding regarding the effects of racket properties on the nature of the game, investigations consider the combined effects of racket properties and their relationship(s) to specific shot types found within the field of play.

The advent of more stringent VOC legislation has resulted in a range of new technologies being utilized in the protective coatings industry. These new technologies require extensive testing to evaluate their performance due to a lack of track record in the market place. This is especially so in the offshore market where premature coating failure can lead to a significant loss of income for the facility owner and expensive repair costs. This has led facility owners to demand ever more stringent accelerated testing protocols to evaluate coating performance. Due to the global nature of the offshore business, an internationally recognized testing protocol is required for the evaluation of high performance coating systems. Both ISO and NACE have recently released test protocols for evaluating coatings in the offshore environment. Recent work has concentrated on evaluation of possible acceptance criteria and comparison of failure mode with that obtained on external coastal exposure. The aim of this paper is to evaluate these new standards using a number of typical offshore schemes and report the results obtained.

Background: Cardiopulmonary exercise testing (CPET) of children can be difficult, since they often lack the coordination for treadmill testing and are too small for cycle ergometry. Previous alternative testing methods using mobile equipment outdoors have proven to be successful. However, motivation and safety issues necessitate new and alternative approaches. The objective of this study was to assess the suitability of trampoline jumping as a modality for CPET compared to traditional treadmill tests as well as developing an appropriate testing protocol. We tested adults for safety reasons.