Repetitive Test Research Articles

Functional Capacity Among Healthy Young Females of Saudi Arabia Using 1 Min Sit-To-Stand Test – A Cross Sectional Study

Background: Functional capacity of an individual is denoting their physical fitness which can be assessed using 6-minute walk test, 1min sit-to stand test etc. The objectives of our study are to assess the functional capacity of healthy young females of Saudi Arabia using 1 min STS and to investigate the relationship between age, height, weight, heart rate, rate of perceived exertion with 1 min STS test. Methods: In this cross-sectional study, a total of 52 young healthy females of Saudi Arabia from 18 to 30 years of age were participated. Results: Fifty-seven participants were voluntarily enrolled for this study, 5 were excluded and totally fifty-two participants were involved in this study. The average repetitions of 1 min sit-to-stand is 38 reps/min. The Pearson correlation analysis indicated that there is a weak and negative correlation between 1 min STS test repetitions and age (r=0.142 p=0.311) height, (r=0.122 p=0.39) and weight (r=0.297 p < 0.05). Weak, positive and significant correlation was observed between HR (T1), percentage of MHR (T1) and 1 min STS test repetitions with (r=0.303 p<0.05, r=0.282 p<0.05) respectively. There was a weak and positive correlation between 1 min STS test and Modified Borg scale (T1) (r=0.167, p=0.238). Conclusion: This study highlights the difference in performances of 1 min STS test between Saudi population and Western countries. The functional capacity of young adult Saudi females is reduced when compared to the western counterpart. This could be because of high prevalence of physical inactivity. KEY WORDS: 1 Min Sit-To-Stand Test, Functional Capacity, Physical Activity, Young Females.

Analysis of Model-Scale Open-Water Test Uncertainty

Abstract Within the frame of CTO’s standard procedure, a propeller open-water test is preceded by a reference measurement, which is taken for a reference propeller model (P356). The results of these measurements are assembled to conduct an open-water test uncertainty analysis. Additional material was gathered from open-water tests that were conducted throughout several research projects on the CP469 model, which is a model of the Nawigator XXI propeller. The latter is a controllable pitch propeller; its pitch was reset before each test repetition. Known procedures for the determination of the open-water test uncertainty do not allow one to extract the manufacture impact directly, without building many models. This factor was addressed with the use of lifting surface calculations. Under certain additional assumptions, these calculations were performed for 100 generic versions of each propeller’s geometry, which were generated by random deviations from the theoretical data within the limits of allowed tolerances. The results of the conducted analyses made it possible to extract separate factors, which were connected to the test’s repeatability, measurement bias and geometry tolerance.

Finger Flexor Weakness in Myasthenia Gravis.

Myasthenia gravis (MG) affects the ocular, bulbar, and proximal limb muscles. The involvement of distal limb musclesis uncommon. MG-related weakness that severely affects the finger flexors and spares finger extensors and intrinsic hand muscles have never been reported. Here, we report a 35-year-old woman with acetylcholine receptor-antibody positive generalised MG who presented with severe bilateral asymmetric (left worse than right) finger flexor weakness during an MG relapse. The remaining muscles including the median and ulnar intrinsic hand muscles were normal. Repetitive nerve stimulation test showed decremental responses of more than 10%. Magnetic resonance imaging showed short-T1 inversion recovery sequences and increased signal intensities in the volar forearm muscles. Needle electromyography revealed fibrillations and positive sharp waves, small amplitude, short-duration, and polyphasic early recruiting motor unit action potentials. Myositis-specific autoantibodies were negative. Muscle biopsy showed neurogenic features. The patient had a good recovery with immunotherapy. We conclude that clinicians should be aware that marked weakness of the finger flexors can occur as a result of an MG relapse and may require early aggressive therapy. Key Words: Electromyography, Finger flexors, Muscle, Biopsy, Myasthenia gravis.

The diagnosis of severe combined immunodeficiency (SCID): The Primary Immune Deficiency Treatment Consortium (PIDTC) 2022 Definitions

Severe combined immunodeficiency (SCID) results from defects in the differentiation of hematopoietic stem cells into mature T lymphocytes, with additional lymphoid lineages affected in particular genotypes. In 2014, the Primary Immune Deficiency Treatment Consortium published criteria for diagnosing SCID, which are now revised to incorporate contemporary approaches. Patients with typical SCID must have less than 0.05 × 109 autologous T cells/L on repetitive testing, with either pathogenic variant(s) in a SCID-associated gene, very low/undetectable T-cell receptor excision circles or less than 20% of CD4 T cells expressing naive markers, and/or transplacental maternally engrafted T cells. Patients with less profoundly impaired autologous T-cell differentiation are designated as having leaky/atypical SCID, with 2 or more of these: low T-cell numbers, oligoclonal T cells, low T-cell receptor excision circles, and less than 20% of CD4 T cells expressing naive markers. These patients must also have either pathogenic variant(s) in a SCID-associated gene or reduced T-cell proliferation to certain mitogens. Omenn syndrome requires a generalized erythematous rash, absent transplacentally acquired maternal engraftment, and 2 or more of these: eosinophilia, elevated IgE, lymphadenopathy, hepatosplenomegaly. Thymic stromal defects and other causes of secondary T-cell deficiency are excluded from the definition of SCID. Application of these revised Primary Immune Deficiency Treatment Consortium 2022 Definitions permits precise categorization of patients with T-cell defects but does not imply a preferred treatment strategy.

Prediction of Concrete Compressive Strength Using Artificial Neural Network

Concrete is the most widely used material by humans after water. Rapid growth in the construction industry, concrete will continue to be the dominant material in the future. Concrete is a composite material like aggregates, water, and admixtures. Destructive testing of concrete to know its strength achieved after the mix design will be an expensive and time-consuming process. With recent advances in soft computing techniques like artificial intelligence, these results can be predicted by feeding the algorithm with a large number of data available to obtain the desired results. In the present research work, it is proposed to use artificial neural networks to predict the strength of different types of concrete. A Multilayer Perceptron has input and output layers, and one or more hidden layers with many neurons stacked together. Data capturing will be done regarding different types of concrete and artificial neural networks are preliminarily trained with various inputs to solve problems with data applica- ble to obtain the desired results. This ANN with captured data helps in minimizing repetitive process and tests involved to obtain the results through experimental procedures which is time, material, and money- consuming with practical difficulties. The advantage of python is that designer can create a customized program for interactive design, Python determination also improve the analytical skill of the student and programs can be converted into executable software. Concrete Cubes are cast to validate the predicted Result of the Software.

Seronegative Myasthenia Gravis Presenting as Dysphagia in a Young Male- A Diagnostic Dilemma

21year old gentleman presented with insidious onset, gradually progressive dysphagia for 2 weeks. There was no other associated signs or symptoms. Initial blood workup, radiological investigations and diagnostic interventions were non-contributory. In the meantime, dysphagia worsened and was found to be progressive with advancement of the day. Oesophageal manometric studies showed gradual weakening of peristaltic contractions after a string of repetitive swallows. Repetitive nerve stimulation test and edrophonium test were suggestive of Myasthenia Gravis; Anti-acetylcholine receptor antibody and anti-MuSK antibody were negative. He was initiated on Pyridostigmine and had improvement of dysphagia after a few days. He has now achieved remission. Hence, we present a curious case of Seronegative Myasthenia Gravis in a young gentleman who presented with only dysphagia recovered with Pyridostigmine.

Nanocubic copper cobaltite for methyl orange degradation through photocatalytic process

In this study, cubic spinel structured CuCo2O4 (Copper cobaltite) nanospheres were fabricated by thermal decomposition method. The visible light degradation of organic contaminant methyl orange (MO) was focused in this study using the synthesized pure CuO, Co3O4 and CuCo2O4 with different weight ratios of raw materials (90:10, 75:25 and 50:50). It could be well realized that after the characterization techniques, the synthesized CuCo2O4 materials resembled cubic spinel structure as confirmed by X-ray diffraction (XRD) investigation. Meanwhile, all the synthesized materials through transmission electron microscopy (TEM) have showed cubic shaped particles and among the CuCo2O4 materials, CuCo2O4 (50:50) expressed not as much of crystallinity due to the agglomerated nanospheres. On the other hand, well crystalline CuCo2O4 (75:25) displayed higher surface area than the other materials when analysed through Brunauer-Emmett-Teller (BET) method. The Fourier transform infra-red (FTIR) spectrum has evinced the formation of CuCo2O4 nanostructures. In addition, the cubic spinel structured CuCo2O4 provided positive results over visible light irradiation. Finally, the CuCo2O4 (75:25) sample has scored high as much of 85% MO degradation compared with others. This sample was progressed with repetitive recycling tests and presented the best photocatalytic degradation efficiency. The upgraded results of CuCo2O4 sample have been linked with the developed synergistic effects during the formation of binary metal oxides. Also, the interfacial electron-hole formation leads to the migration and hindering of charge carriers for visible light activity.

Results from Canton Grisons of Switzerland suggest repetitive testing reduces SARS-CoV-2 incidence (February–March 2021)

In February 2021, in response to emergence of more transmissible SARS-CoV-2 virus variants, the Canton Grisons launched a unique RNA mass testing program targeting the labour force in local businesses. Employees were offered weekly tests free of charge and on a voluntary basis. If tested positive, they were required to self-isolate for ten days and their contacts were subjected to daily testing at work. Thereby, the quarantine of contact persons could be waved.Here, we evaluate the effects of the testing program on the tested cohorts. We examined 121,364 test results from 27,514 participants during February–March 2021. By distinguishing different cohorts of employees, we observe a noticeable decrease in the test positivity rate and a statistically significant reduction in the associated incidence rate over the considered period. The reduction in the latter ranges between 18 and 50%. The variability is partly explained by different exposures to exogenous infection sources (e.g., contacts with visiting tourists or cross-border commuters). Our analysis provides the first empirical evidence that applying repetitive mass testing to a real population over an extended period of time can prevent spread of COVID-19 pandemic. However, to overcome logistic, uptake, and adherence challenges it is important that the program is carefully designed and that disease incursion from the population outside of the program is considered and controlled.

Glycaemic control for patients with severe acute brain injury: Protocol for a systematic review.

Hyperglycaemia is common in patients with acute brain injury admitted to an intensive care unit (ICU). Many studies have found associations between development of hyperglycaemia and increased mortality in hospitalised patients. However, the optimal target for blood glucose control is unknown. We want to conduct a systematic review with meta-analysis and trial sequential analysis to explore the beneficial and harmful effects of restrictive versus liberal glucose control on patient outcomes in adults with severe acute brain injury. We will systematically search medical databases including CENTRAL, Embase, MEDLINE and trial registries. We will search the following websites for ongoing or unpublished trials: http://www.controlled-trials.com/, http://www. gov/, www.eudraCT.com, http://centerwatch.com/, The Cochrane Library's CENTRAL, PubMed, EMBASE, Science Citation Index Expanded and CINAHL. Two authors will independently review and select trials and extract data. We will include randomised trials comparing levels of glucose control in our analyses and observational studies will be included to address potential harms. The primary outcomes are defined as all-cause mortality, functional outcome and health-related quality of life. Secondary outcomes include serious adverse events including hypoglycaemia, length of ICU stay and duration of mechanical ventilation, and explorative outcomes including intracranial pressure and infection. Trial Sequential Analysis will be used to investigate the risk of type I error due to repetitive testing and to further explore imprecision. Quality of trials will be evaluated using the Cochrane Risk of Bias tool, and quality of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. The results of the systematic review will be disseminated through peer-reviewed publication. With the review, we hope to inform future randomised clinical trials and improve clinical practice.

Repetitive nanoindenter scratch testing of polydopamine/polytetrafluoroethylene-based thin coatings

Repetitive nanoindenter scratch testing and scanning electron microscopy were used to evaluate the scratch resistance, deformation, and mechanisms of failure of polydopamine (PDA)/polytetrafluoroethylene (PTFE)-based coatings deposited on both polished and roughened 60NiTi substrates. PDA was used as an adhesive layer between the substrate and the PTFE top layer with and without 0.25 wt% graphite particles (GPs). The roughened substrate enabled mechanical interlocking with the coatings that prevented global delamination which occurred with the coatings on the polished substrate due to weak adhesion. The inclusion of GPs improved the coating cohesion and enabled the PDA/PTFE coating with GPs on the roughened substrate to compact into a more plowing-resistant layer with stronger interlocking with the substrate roughness. Therefore, the GP-containing coating deposited on a roughened substrate showed far superior performance, and it is a promising solid lubricant for tribological applications that involve repetitious sliding at high contact pressures, such as bearings and gears.

Dynamic characteristics and fracture process of marble under repeated impact loading

Understanding dynamic behaviours of rock materials under repeated blast loading is of great significance to evaluate stability of the surrounding rock in rock tunnel engineering. In this study, repetitive impact loading tests were conducted on marble specimens to investigate dynamic characteristics of the rock. Besides, numerical model of the SHPB test was established based on the finite element software LS-DYNA to simulate repeated impact loading for the first time, and repeated impact tests with constant and variable velocities were carried out on the rock numerically. The results show that, stress-strain relationships of the marble are sensitive to both impact velocity and impact number. As the impact velocity increases, dynamic compressive strength of the specimens increases, and the impact numbers that the specimens need to be destroyed decrease. Strain rate increases with increasing impact number under the same impact velocity. When the peak stress is below 120 % of the static strength of the rock, it will not cause severe damage in the marble specimen with fewer impact number. Fracture process of the rock could be separated into four stages: local failure on the end faces, failure in the core, rapid development of failure and slow development of failure.

Reducing unnecessary routine laboratory testing for noncritically ill patients with COVID-19.

Reducing unnecessary routine laboratory testing is a Choosing Wisely® recommendation, and new areas of overuse were noted during the COVID-19 pandemic. To reduce unnecessary repetitive routine laboratory testing for patients with COVID-19 during the pandemic across a large safety net health system. This quality improvement initiative was initiated by the System High-Value Care Council at New York City Health + Hospitals (H + H), the largest public healthcare system in the United States consisting of 11 acute care hospitals. four overused laboratory tests in noncritically ill hospitalized patients with COVID-19 were identified: C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), and procalcitonin. A two-pronged electronic health record intervention was implemented consisting of (1) nonintrusive, informational nudge statements placed on selected order sets, and (2) a forcing function of one consecutive day limit on ordering. The average of excess tests per encounter days (ETPED) for each of four target laboratory testing only in patients with COVID-19. Interdisciplinary System High-Value Care Council identified four overused laboratory tests (inflammatory markers) in noncritically ill hospitalized patients with COVID-19: C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), and procalcitonin. Within an 11-hospital safety net health system, a two-pronged electronic health record intervention was implemented consisting of (1) nonintrusive, informational nudge statements placed on selected order sets, and (2) a forcing function of one consecutive day limit on ordering. The preinterventionperiod (March 16, 2020 to January 24, 2021) was compared to the postintervention period (January 25, 2021 to March 22, 2022). Time series linear regression showed decreases in CRP (-17.9%, p < .05), ferritin (-37.6%, p < .001), and LDH (-30.1%, p < .001). Slope differences were significant (CRP, ferritin, and LDH p < 0.001; procalcitonin p < 0.05). Decreases were observed across weekly averages: CRP (-19%, p < .01), ferritin (-37.9%, p < .001), LDH (-28.7%, p < .001), and procalcitonin (-18.4%, p < .05). This intervention was associated with reduced routine inflammatory marker testing in non-intensive careunit COVID-19 hospitalized patients across 11 hospitals. Variation was high among individual hospitals.

Probabilistic friction model for aluminium–steel Asymmetric Friction Connections (AFC)

Multiple physical variables potentially affect the friction coefficient of Asymmetric Friction Connections (AFC). This paper discusses the cyclic response of a class of AFC subjected to repeated load protocols. Two phenomena are observed. First, the friction coefficient, initially higher due to wear phenomena and moment-axial force-shear force interaction, stabilizes after multiple cycles. Second, the test repetitions on the same specimen show that the friction coefficient at the beginning of the loading protocol is higher than that observed at the end of the antecedent load protocol. The experimental data prove that the dissipated energy during the current load test, temperature, and the specimen’s history affect the friction coefficient. This paper presents two probabilistic friction models calibrated using a Bayesian approach. The first engineering-oriented model is dependent on the dissipated hysteretic energy. The second includes the measured temperature as a model regressor to estimate its possible role in the response. The proposed probabilistic models can be used to predict with satisfactory accuracy the friction coefficient in Coulomb-like hysteresis models of AFCs.

Analysis of Repetitive Bending on Flexible Wireless Power Transfer (WPT) PCB Coils for Flexible Wearable Devices

In this article, we first designed, measured, and analyzed flexible wireless power transfer (WPT) coils with repetitive bending cycles. To analyze any changes in electrical characteristics through repetitive bending cycles, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times3$ </tex-math></inline-formula> cm flexible printed circuit board (PCB) coils were fabricated using polyimide substrates. Different coil configurations are designed to find a mechanically robust, flexible PCB coil design. First, we analyzed single-layer and double-layer coils. Generally, via is the mechanically weakest part of the PCB, hence the diameter of the via varies to observe the effect of repetitive bending cycle. Ten thousand bending cycles with a bending radius of 3 mm and a bending cycle frequency of 1 Hz were used to analyze the electrical changes. Moreover, the bending position of the coil is varied to observe the bending effect. The flexible coil’s direct current (dc) resistance is measured during the bending cycle. After the repetitive bending test is completed, the coil impedance is analyzed in a frequency domain. As a result, we conclude that the flexible WPT coil is robust from mechanical stress when the layer of the coil is single a layer, the bending line is applied vertically, and the diameter of the via is small.

DLNLF-net: Denoised local and non-local deep features fusion network for malignancy characterization of hepatocellular carcinoma

IntroductionHepatocellular carcinoma (HCC) is a primary liver cancer with high mortality rate. The degree of HCC malignancy is an important prognostic factor for predicting recurrence and survival after surgical resection or liver transplantation in clinical practice. Currently, deep features obtained from data-driven machine learning algorithms have demonstrated superior performance in characterising lesion features in medical imaging processing. However, previous convolutional neural network (CNN)-based studies on HCC lesion characterisation were based on traditional local deep features. The aim of this study was to propose a denoised local and non-local deep features fusion network (DLNLF-net) for grading HCC. MethodsGadolinium-diethylenetriaminepentaacetic-acid-enhanced magnetic resonance imaging data of 117 histopathologically proven HCCs were collected from 112 patients with resected HCC between October 2012 and October 2018. The proposed DLNLF-net primarily consists of three modules: feature denoising, non-local feature extraction, and bilinear kernel fusion. First, local feature maps were extracted from the original tumour images using convolution operations, followed by a feature denoising block to generate denoised local features. Simultaneously, a non-local feature extraction block was employed on the local feature maps to generate non-local features. Finally, the two generated features were fused using a bilinear kernel model to output the classification results. The dataset was divided into a training set (77 HCC images) and an independent test set (40 HCC images). Training and independent testing were repeated five times to reduce measurement errors. Accuracy, sensitivity, specificity, and area under the curve (AUC) values in the five repetitive tests were calculated to evaluate the performance of the proposed method. ResultsDenoised local features (AUC 89.19%) and non-local features (AUC 88.28%) showed better performance than local features (AUC 86.21%) and global average pooling features (AUC 87.1%) that were derived from a CNN for malignancy characterisation of HCC. Furthermore, the proposed DLNFL-net yielded superior performance (AUC 94.89%) than a typical 3D CNN (AUC 86.21%), bilinear CNN (AUC 90.46%), recently proposed local and global diffusion method (AUC 93.94%), and convolutional block attention module method (AUC 93.62%) for malignancy characterisation of HCC. ConclusionThe non-local operation demonstrated a better capability of yielding global representation, and feature denoising based on the non-local operation achieved performance gains for lesion characterisation. The proposed DLNLF-net, which integrates denoised local and non-local deep features, evidently outperforms conventional CNN-based methods in the malignancy characterisation of HCC.

The brief case for everyday problems: a proposal of two brief alternate forms of the Everyday Problems Test.

Everyday Problems Test (EPT; Willis and Marsiske, Manual for the everyday problems test, Pennsylvania State University, Pennsylvania, 1993) is an 84-item performance-based measure of older adults' everyday cognitive competencies in seven everyday domains (e.g., finance, reading prescription). Its length makes it disadvantageous in the typical time-constrained testing context. Due to the potential practice effects, it is also impractical for longitudinal and intervention studies which require repetitive testing. We have addressed these issues by adapting two brief forms of EPT, with 14 items each. The psychometric evaluation of these two versions was conducted on a sample of 157 cognitively healthy older adults. Both brief forms demonstrated good internal consistency, high inter-correlation, and have shown satisfactory concurrent criterion-related validity based on their correlations with socio-demographic and cognitive variables. Results indicate that the two proposed brief forms can be a valuable tool in assessing the everyday cognitive competence of healthy older adults either as a one-time screening instrument or as a pretest-posttest difference indicator of the intervention efficacy.

“Surgical Wings”: Forceps-Based Device Improves Surgeon Hand Ergonomics

Introduction: Surgical instruments require ongoing improvement for optimal ergonomics. Our novel “surgical wings” (SW) device is designed to improve steadiness of forceps and decrease hand fatigue and discomfort. Methods: A total of 21 surgical trainees and attending surgeons participated in this study at a single academic center. The effect of SW on ergonomics of various tasks using forceps was evaluated. Each participant performed tasks with and without SW attached to the forceps. Surface electromyography (EMG) was used to record thenar muscle activity during all tasks. Post testing survey was conducted to evaluate participants’ assessment of the SW effect on task performance, hand fatigue and comfort. Results: Continuous Pinch test: The steadiness index (ratio of standard deviation to the mean of the EMG voltage) significantly improved with the device use (p value 0.031). Repetitive Pinch test: EMG values during rest periods were significantly lower with the device (p value 0.031). Pegboard test: No significant difference in the speed of completion or number of peg drops was detected in trials performed with and without the device. Post-testing survey: Participants scored favorably the device performance during pinch tests and neutral during the pegboard task favorably. Conclusion: Based on our data, SW effectively decreases hand muscle effort and allows for better hand relaxation. The device significantly improves the steadiness of forceps use during sustained pinch. The device use did not negatively affect speed or tasks performance precision. Favorable subjective assessment of device ergonomics by participants correlated well with the EMG data.

(Digital Presentation) Design of High Barrier Property and Flexible Inorganic/Polymer Hybrid Film for Encapsulation of Flexible Electronics

Designing encapsulation film with both high barrier property and excellent flexibility has been challenging for the current brittle inorganic films owing to the strain-induced cracking. Inorganic/organic multilayer has been proposed due to the organic layer can function as buffers of the inorganic layer and defect-decoupling layer, realizing the improvement of flexibility and maintaining barrier property. Polydimethylsiloxane (PDMS) was widely used as an organic encapsulation layer due to its high stability, elasticity, and transparency. The introduction of PDMS helps the barrier film to resist distorting under the bending motions. However, the delamination and cracking occurred under bending motion in a small curvature radius due to the mismatched strain and coefficient of thermal expansion (CTE) between PDMS and inorganic films such as Al2O3. Realization of improving their strain and CTE mismatch is possible by doping nanoparticles into PDMS. The Al2O3/PDMS hybrid film with the doping of SiO2 fabricated via atomic layer infiltration (ALI) method showed mechanical stability and endure 1000 repetitive stretch tests with 1%, but the water vapor transmission rate (WVTR) was only 10-3 g/m2/day, which was attributed to the lower crosslinking density of PDMS result in higher free volume and chain mobility. It’s a challenge to develop a strategy for improving the crosslink density of PDMS. In this work, the PDMS-based composite substrate with engineered stiffness was developed by employing the addition of silane coupling agent and SiO2. Atomic layer infiltration (ALI) coupled with UV-curing was introduced for sub-surface cross-linking of PDMS in Al2O3/SiO2/PDMS hybrid film, and the resulted Al2O3/SiO2/PDMS hybrid film showed highly stretchable and barrier properties. The result indicates that Al2O3/SiO2/PDMS hybrid film is a promising encapsulation film applicable to flexible electronics.Keywords: atomic layer infiltration (ALI), flexible film, encapsulation, UV-curing method, water vapor transmission rate (WVTR)Refs. Y. Li, D. Wen, Y. Zhang, Y. Lin, K. Cao, F. Yang, R. Chen, Highly-stable PEN as a gas-barrier substrate for flexible displays via atomic layer infiltration, Dalt. Trans. (2021) 16166–16175. https://doi.org/10.1039/d1dt02764f.Zhang, D. Wen, M. Liu, Y. Li, Y. Lin, K. Cao, F. Yang, R. Chen, Stretchable PDMS Encapsulation via SiO2 Doping and Atomic Layer Infiltration for Flexible Displays, Adv. Mater. Interfaces. 9 (2022) 1–9. https://doi.org/10.1002/admi.202101857.

Electrospun Nanofiber-Based Electrodes Composed of Core-Shell (PVDF)-(Al) Structures for Application to Flexible Electronics

Nanostructured transparent conductors have been studied intensively for application to flexible and transparent electronic devices. Among diverse nanomaterials, electrospun nanofibers provide several advantages over other nanomaterials, including a high aspect ratio, uniform distribution, and a facile fabrication process. In the present study, an electrode composed of a core-shell (PVDF)-(Al) structured nanofiber mesh film was fabricated via electrospinning and sputtering processes, without any hightemperature heat treatment or wet chemical treatment. A free-standing circular collector was used to form a PVDF nanofiber mesh film, to perform the conformal coating of Al onto the PVDF surfaces. The parameters of the tip-to-collector distance and the electrospinning voltage needed to stably form a PVDF nanofiber mesh film were determined. The sheet resistance of the mesh film was dramatically reduced from 1870 Ω/sq. to 154 Ω/sq. when the sputtering time was increased from 2 min to 4 min, an outcome explained by the changed surface morphology of the Al coating layer. The sheet resistance decreased from 657 Ω/sq. to 15.4 Ω/sq. with an increase in the electrospinning time from 2 min to 8 min due to the increased numbers of nanofibers and junctions. When the transmittance at 550 nm with respect to the sheet resistance was plotted for these mesh films, the graph was divided into the bulk and percolation regimes. Mesh films with transmittance rates that exceeded 85% exhibited sheet resistance that clearly increased with an increase in transmittance, indicating a percolation network. Finally, the durability of the core-shell (PVDF)-(Al) structured nanofiber mesh film was evaluated using a repetitive bending test, the results of which clearly showed superior performance over Al thin film. With inexpensive metal Al, a competitive flexible and transparent electrode was fabricated in the form of a core-shell (PVDF)-(Al) structured nanofiber mesh film.

Evaluation of heat removal property in W/Cu/RAFM steel joint by using electron beam facility

• The durability of the W/Cu/JLF-1 joint sample fabricated by brazing was confirmed by performing steady-state and repetitive heat loading experiments. • The W/Cu/JLF-1 showed excellent heat removal performance under the steady-state heat loading. • A degradation of the heat removal performance was confirmed during the repetitive heat loading. • The delamination which could lead to the barrier of efficient heat transfer was confirmed after the repetitive heat loading of ∼6.0 MW/m 2 . A reliable technique for creating joints between tungsten (W) and Reduced Activated Ferritic/Martensitic (RAFM) steel with a pure-copper (Cu) interlayer (W/Cu/RAFM steel) has been explored for developing the heat removal component in the baffle and dome of a divertor. The first joint sample of W/Cu/RAFM steel was fabricated by using a brazing technique described in our previous work. In this work, to evaluate the heat removal property, a joint sample was subjected to a steady-state and a repetitive heat loading test with an electron beam facility (ACT2). In the steady-state heat loading test, a step-wised static heat load with ∼0.7, ∼1.0, ∼1.9, ∼2.7, ∼3.6, ∼4.4 and ∼6.0 MW/m 2 was applied to the joint sample. The temperatures on the W and RAFM steel showed a linear increasing tendency, as a function of the heat loading value. Also, in the repetitive heat loading test, a 30 s pulse width of 100 cycles was applied with a maximum heat loading value of ∼2.8 and ∼6.0 MW/m 2 . The obvious temperature excursion, while increasing the heat cycles, was confirmed at ∼6.0 MW/m 2 . After the heat loading, a major crack in the vicinity of the interface between the W and Cu was confirmed. This crack led to the degradation of the heat removal performance over ∼6.0 MW/m 2 .