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Extraction, storage and transportation of coal are complicated by the danger of spontaneous combustion centers due to toxic gases emission. At various technological processes, the formation of clusters consisting of coal particles of various sizes is possible. In the course of the research, the influence of the size of coal particles on the danger of spontaneous combustion of oxidizing material clusters was estimated. The studies of coal chemical activity have shown that for most seams of Kuzbass mines, the amount of absorbed oxygen increases significantly with decreasing particle size. Coal dust can be more active than coal in 3-8 times. For some seams, the coal breakage has almost no effect on its chemical activity in relation to oxygen. It is determined that the duration of incubation period of spontaneous combustion also varies depending on the size of particles forming the coal cluster. For the appearance of spontaneous combustion centers, the size of coal dust clusters may be in 2– 4 times smaller than for coal. In order to increase the safety of work for all the seams it is necessary to study the chemical activity in relation to oxygen, the tendency to spontaneous combustion, and the duration of the incubation period not only for coal samples, but also for coal dust.

In this study, the bipolar switching behaviors in ZnO/HfO2 bilayer resistive random-access memory (RRAM), depending on different metal top electrodes (TE), are analyzed. For this purpose, devices with two types of TE–TiN/Ti and Pd, which have varying oxygen affinities, are fabricated. X-ray diffraction (XRD) analysis shows that ZnO has a hexagonal wurtzite structure, and HfO2 exhibits both monoclinic and orthorhombic phases. The average grain sizes are 10.9 nm for ZnO and 1.55 nm for HfO2. In regards to the electrical characteristics, the I–V curve, cycling test, and voltage stress are measured. The measurement results indicate that devices with TiN/Ti TE exhibit lower set and higher reset voltage and stable bipolar switching behavior. However, a device with Pd TE demonstrates higher set and lower reset voltage. This phenomenon can be explained by the Gibbs free energy of formation (∆Gf°). Additionally, the Pd TE device shows unstable bipolar switching characteristics, where unipolar switching occurs simultaneously during the cycling test. This instability in devices with Pd TE could potentially lead to soft errors in operation. For guaranteeing stable bipolar switching, the oxygen affinity of material for TE should be considered in regards to ZnO/HfO2 bilayer RRAM. [ABSTRACT FROM AUTHOR]

Self-modeling (SM) and self-control (SC) feedback can be presented as two solutions for learning improvement. Therefore, the aim of the present study was to investigate the effects of SM and SC feedback on 100-m freestyle performance of professional swimmers and waterpolo players. 25 elite male swimmers and waterpolo players, were randomly assigned to four groups: swimmer group with SM, swimmer group with SM and SC feedback, waterpolo players group with SM, and waterpolo players group with SM and SC feedback. 100-m freestyle times and performance were recorded. SM and SC feedback for the participants were utilized at the acquisition stage. The device used included a Lenovo B570 laptop and an Exilim ZR200 canon camcorder. SM and SC feedback presented to the swimmers and waterpolo players led to improved speed and results, and the effect of presenting SM with SC feedback to swimmers had better results. In conclusion, the present study indicates that SC modeling of watching video is a suitable method for professional swimmers. Water polo trainers can also use SM and SC feedback to enhance their players' swimming technique.

Mangroves are well known for their ability to sequester and store a large amount of carbon within their plant parts and sediment. This characteristic is termed as blue carbon and important to combat the global warming through carbon sink and carbon storage. Studies on blue carbon are vast globally however the environmental parameters that regulated the mangrove carbon stock remain limited and require urgent investigation to understand the factors controlling the ecosystem’s blue carbon projection. Therefore, this study was conducted to quantify both the above and belowground mangrove carbon stocks and the carbon stocks relation to physical parameters in Setiu Lagoon, Terengganu. The value was 90.92 t C ha−1 and 25.30 t C ha−1, respectively. Rhizophora apiculata was with the highest aboveground carbon stock with storage capacity of 48.91 t c ha−1. In terms of diameter at breast height class size, Class 2 (10.1–20.0 cm) was the highest with 43.49 t C ha−1. For belowground carbon stock, coarse roots had the highest value with 12.70 ± 2.84 t C ha−1, followed by fine roots with 9.81 ± 1.97 t C ha−1, and dead roots with 3.06 ± 1.12 t C ha−1 and had significant differences (p < 0.05). Layer 41–50 cm in Setiu Lagoon had the highest belowground carbon stock with 7.13 ± 0.47 t C ha−1. Soil pore-water pH showed to significantly positively correlated with the belowground stock at R2 = 0.35, p < 0.05. As conclusion, our study contributes to the mangrove carbon stock of lagoon mangrove forest and highlight the importance of pH as a crucial parameter in future carbon stock study particularly for tropical mangrove forest.