Increasing the longitudinal bending stiffness of runners’ habitual shoes: An appropriate choice for improving running performance?

This study analysed the effects of increasing the longitudinal bending stiffness (LBS) of runners’ habitual shoes on the metabolic energetic demand, lower limb muscle activation and stride spatiotemporal parameters during a prolonged running session through classical group investigation, as well as a more individualised approach. Eleven recreational male participants ran overground for 40 min at 95% of their ventilatory anaerobic threshold with their own shoes or their shoes with higher LBS (stiff carbon plate inserted under insole). The net energetic cost of running, lower leg muscle activation and spatiotemporal parameters were measured during the prolonged running. The variables of interest were analysed for 1 min in seven time intervals. There were no main effects of LBS or interaction effects with running duration on the group averaged variables. Overall, the participant-specific metabolic effects induced by an increased shoe LBS were not beneficial. Beneficial metabolic effects were more likely to occur when the increased LBS induced a decrease or no change in the ground contact time relative to their habitual shoes, as well as for taller runners. Increasing the LBS in runners’ habitual shoes did not induce systematic metabolic effects for all the runners and may not be beneficial for performance purposes if the runners’ shoe habits were too disrupted.

Effect of the welding process on microstructure, microhardness and residual stresses of capacitor discharge stud welded joint

Capacitor discharge (CD) stud welding is a common and fast connection technology. This paper presents an experimental and simulation study of the stud weld joint of copper stud and carbon plate. An optimized stud welding process was proposed based on microstructure, microhardness and residual stresses of CD stud welded joint. The results show that a narrow weld seam with widmanstaten structure were formed because of quickly cooling. For the longer stud extension length, the width of weld zone becomes wider and the microstructure becomes more uniform. As the increase of welding voltage and stud extension length, the microhardness increases then decreases. However, the residual stresses are increased with welding voltage increases, while they are decreased with the increases of stud extension length. The optimized welding voltage and stud extension length should be designed to 90 V and 5 mm, respectively. This study will provide a great significance to the stud welding on site.

THE INFLUENCE OF NaCl SOLUTION FLOW RATE ON ION ABSORPTION OF CAPACITIVE ELECTRIC CARBON PLATE

Research on desalination technology in seawater is being developed. This is because sea water has not been used optimally to meet community needs. One of the rapidly developing desalination systems is desalination technology using a capacitive carbon plate. The development of this desalination system technology is carried out using electrode plates made of carbon. These plates are capable of absorbing salt ions through the porous surface. The amount of ion absorbed is determined by the pore surface structure of the plate, the salt flow rate, the number of plates used, the applied voltage and other factors. The salt flow rate between the carbon plates determines the speed of the salt ions to reach the smallest pores on each plate surface. For this reason, this article has conducted research by testing the variation in the flow rate of NaCl solution to the amount of salt ions absorbed on the carbon plate.

Coupling Hierarchical Ultrathin Co Nanosheets With N-Doped Carbon Plate as High-Efficiency Oxygen Evolution Electrocatalysts

The rational design of cost-effective and highly efficient catalysts for the oxygen evolution reaction (OER) is vastly desirable for advanced renewable energy conversion and storage systems. Tailoring the composition and architecture of electrocatalysts is a reliable approach for improving their catalytic performance. Herein, we developed hierarchical ultra-thin Co nanosheets coupled with N-doped carbon plate (Co-NS@NCP) as an efficient OER catalyst through a feasible and easily scalable NaCl template method. The rapid dissolution-recrystallization-carbonization synthesis process allows Co nanosheets to self-assemble into plenty of secondary building units and to distribute uniformly on N-doped carbon plate. Benefitting from the vertically aligned Co nanosheet arrays and hierarchical architecture, the obtained Co-NS@NCP possess an extremely high specific surface area up to 446.49 m2 g−1, which provides sufficient exposed active sites, excellent structure stability, and multidimensional mass transfer channels. Thus, the Co-NS@NCP affords remarkable electrocatalytic performance for OER in an alkaline medium with a low overpotential of only 278 mV at 10 mA cm−2, a small Tafel slope, as well as robust electrocatalytic stability for long-term electrolysis operation. The present findings here emphasize a rational and promising perspective for designing high-efficiency non-precious electrocatalysts for the OER process and sustainable energy storage and conversion system.

Immobilization of Crude Polyphenol Oxidase Extracts from Apples on Polypyrrole as a Membrane for Phenol Removal

This research aims to make a polypyrrole (PPy) membrane and crude extract of polyphenol oxidase (PPO) as a membrane of mPPy/PPO apple extracts. The membrane of PPy/PPO-apple extract has been synthesized by the electrodeposition method. The electrolyte composition consists of a mixture of 0.10-0.20 M pyrrole (Py) and 50-100% PPO apple extract, which is stable using 50 mM of phosphate buffer solution at pH 6.80-7.00 and room temperature. The electrodeposition process is used 400 mesh steel gauze anode ST-304 and carbon plate cathode. Electrodeposition is carried out at potential = 5.00-6.00 V; current = 0.02-0.25 A; the distance from both electrodes = 1.00-2.00 cm for 300-500 seconds. The results from the deposition of PPy/PPO apple extract of the anode are a membrane of mPPy/PPO-apple extract, with total enzyme activity (U) = (957,1441, 2287 and 1754) using 2.00-5.00 mM phenol as a substrate which is measured based on the UV-visible spectrophotometric method. PPy and mPPy/PPO-apple extracts were characterized by SEM and SEM-EDS. The membrane of mPPy/PPO-apple extract can be used to remove phenol in industrial wastewater samples is 50-65% with a filtration capacity of 500 mL for 2 hours.

Photocatalytic Fuel Cell Based on Zinc Oxide Loaded Carbon Plate Photoanode for Simultaneous Photocatalytic Degradation of Azo Dyes and Electricity Generation

Photocatalytic fuel cell (PFC) is promising to own its synchronous degradation of organic pollutants with electricity generation under illumination of light. The oxidation and reduction process promote the conversion of chemical energy in the pollutants into electrical energy. In this study, PFC is driven by the electrode reactions between the zinc oxide loaded carbon plate (ZnO/C) photoanode and carbon plate cathode under irradiation of UVA light. The ZnO/C photoanode was successfully fabricated by using simple ultrasonication-annealed method and investigated by XRD, SEM and EDX. To investigate the capability of the PFC, reactive red 120 (RR120), congo red (CR) and acid orange 7 (AO7) are employed well compared among themselves. The results indicated that the molecular structure of azo dyes with different adsorption of light by dye itself, number of azo bonds and sulfonic groups can be the crucial factors of decolorization in the PFC. The photocatalytic fuel cell with AO7 as sacrificial agent was able to perform 82.43% of decolorization efficiency, a maximum short circuit current (JSC) of 0.0017 mA cm-2 and maximum power density (Pmax) of 0.0886 µW cm-2.