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•Coal sample soaked for almost seven years were selected and used.•Evolution of activation energies with conversion degree in oxidation was analyzed.•Changes in physical and chemical ...structures after water immersion were studied.•Mechanism for the easier oxidation of dried soaked coal was revealed.
Spontaneous combustion of the lone-term water soaked coal has been frequently taken place during air drying after water discharge, however the reason for the easier spontaneous combustion of water-immersed coal is still not clear. In this study, raw and coal sample soaked for nearly seven years was selected, low-temperature oxidation and crossing point temperature tests were first analyzed. The increased gaseous products concentration and the decreased crossing point temperature indicated that water immersed coal was more prone to oxidation and spontaneous combustion. Besides, the species and concentration of cations, pore structure, functional groups and thermal kinetic parameters were measured by ICP-MS, N2 adsorption, IR and TG analysis. The concentration of alkali cations that had the inhibitory effect on spontaneous combustion was found to decrease in the water-immersed coal, the pore size and specific surface area were enlarged, thus providing suitable internal conditions for the occurrence of coal spontaneous combustion. Moreover, the variation of functional groups and activation energies during the oxidation process showed that numbers of active sites were accumulated in the process of long-term water immersion and the water immersed coal can be oxidized at low temperatures, leading to the shorting of the side chain and the generation of oxygen-containing functional groups. Therefore, it is proposed that the water immersion process enhances the concentration of active sites in coal and provide physical channels for its oxidation, which led to rapid oxidation and even uncontrollable spontaneous combustion of water-immersed coal. The results help with our understanding of the mechanism of long-term water immersion on spontaneous combustion of coal, in addition to prevent the coal fires of water immersed coal by reducing the concentration of primary active sites.
This collaborative research between a team of digital technology developers and academic researchers investigates how social interaction affects visitors' experience during a virtual reality (VR) ...underwater seascape exploration. Prior research in immersive VR focused more on individual perceptions of immersion, interactive features and enjoyment. Analysis of focus-group discussions revealed three categories of immersion, interaction with the virtual environment (VE) and social interaction salient to satisfaction with the experience. Moderated mediation analysis of survey results from a full-scale trial (N = 234) show that the three variables had a significant role in experience satisfaction and loyalty intentions. Specifically, immersion mediates person-VE interaction effects on satisfaction and loyalty. The results contrast with previous findings from online gaming contexts, showing that social interactions decrease the impact of immersion on satisfaction and loyalty. We call for caution in the positioning and communication of VR experiences and for further research in other settings.
The use of temporary immersion systems (TIS) for plant micropropagation is an efficient technique for plant production, and we have applied it for the production of alstroemerias. This method ...involves the cultivation of explants such as rhizomes and axillary buds in a nutrient medium to stimulate shoot growth. TIS offer advantages such as accelerated multiplication processes, uniform production, and cost reduction. This process has shown promise in meeting the growing demand for alstroemeria plants in the market. This chapter describes a specific protocol for temporary immersion bioreactor micropropagation of the "Albatroz" cultivar, with the potential for large-scale automation.
Daily compensable cold exposure in humans reduces shivering by ~20% without changing total heat production, partly by increasing brown adipose tissue thermogenic capacity and activity. Although ...acclimation and acclimatization studies have long suggested that daily reductions in core temperature are essential to elicit significant metabolic changes in response to repeated cold exposure, this has never directly been demonstrated. The aim of the present study is to determine whether daily cold-water immersion, resulting in a significant fall in core temperature, can further reduce shivering intensity during mild acute cold exposure. Seven men underwent 1 h of daily cold-water immersion (14°C) for seven consecutive days. Immediately before and following the acclimation protocol, participants underwent a mild cold exposure using a novel skin temperature clamping cold exposure protocol to elicit the same thermogenic rate between trials. Metabolic heat production, shivering intensity, muscle recruitment pattern, and thermal sensation were measured throughout these experimental sessions. Uncompensable cold acclimation reduced total shivering intensity by 36% (
= 0.003), without affecting whole body heat production, double what was previously shown from a 4-wk mild acclimation. This implies that nonshivering thermogenesis increased to supplement the reduction in the thermogenic contribution of shivering. As fuel selection did not change following the 7-day cold acclimation, we suggest that the nonshivering mechanism recruited must rely on a similar fuel mixture to produce this heat. The more significant reductions in shivering intensity compared with a longer mild cold acclimation suggest important differential metabolic responses, resulting from an uncompensable compared with compensable cold acclimation.
Several decades of research have been dedicated to reducing the presence of shivering during cold exposure. The present study aims to determine whether as little as seven consecutive days of cold-water immersion is sufficient to reduce shivering and increase nonshivering thermogenesis. We provide evidence that whole body nonshivering thermogenesis can be increased to offset a reduction in shivering activity to maintain endogenous heat production. This demonstrates that short, but intense cold stimulation can elicit rapid metabolic changes in humans, thereby improving our comfort and ability to perform various motor tasks in the cold. Further research is required to determine the nonshivering processes that are upregulated within this short time period.
Hypothermia caused by cold water immersion is one of the main causes of death in marine accidents. Immersion suit is a kind of protective clothing when implementing flying tasks over the sea in cold ...seasons, with the main function to slow down the loss of human heat in water and prolong the survival time. In this study, the thermal properties and wearing types of immersion suit and underwear were analyzed. The subjects with internal- and external-wear immersion suit exposed to the experimental environments for 2 h in five working conditions. The core temperature, weighted average skin temperature, and average body temperature were measured and calculated. Both internal- and external-wear immersion suits could fulfil the cold protection requirements under the experimental conditions. The results of clothing parameter tests and physiological experiments both exhibit that the external-wear immersion suit has better thermal insulation effect. And the tolerance time in low-temperature water was predicted, which is crucial for effective and efficient rescue during shipwreck in adverse thermal scenarios. In future research, a comprehensive evaluation and analysis of the thermal insulation performance of immersion suit could be completed in combination with the water ingress of the clothing, the subjects’ thermal comfort, and flexibility of the clothing.
The study is to perform thermodynamic, economic and thermoeconomic assessments for two different direct immersion cooling data center systems which are the single-phase and the two-phase immersion ...cooling systems with the operating ranges of 3.2–27.6 kW and 6.8–15.9 kW, respectively. The two-phase cooling system achieves 72–79% better coefficient of performance trends than the single-phase cooling system. According to the present worth method, the replacement and the energy costs are found as the most dominant future cost terms for the two-phase and the single-phase cooling systems, respectively. The annual exergy cost of the two-phase cooling system is found up to 4.91 times the annual energy costs due to the dominant effects of the destruction and loss terms. Moreover, both cooling data center systems are compared to the existing air-cooled data center unit. They are found economically infeasible for the server power rates below 5 kW because of their higher capital investment costs while they become more affordable for higher server power rates with lower future cost terms.
•Single- and two-phase data center cooling systems are experimentally tested.•Two-phase cooling has nearly 75% and 5.1% better COP and PUE trends, respectively.•Energy cost is the most dominant future cost terms for the single-phase cooling.•Carbon cost is the minimum future cost term for both systems.•Annual exergy cost is found 4.91 times as high compared to the annual energy cost.
Magnesium (Mg) and its alloys have been regarded as one of the most promising biodegradable implant materials, whereas the rapid degradation rate and potential cytotoxicity hinder their clinic ...applications. In order to improve the biocompatibility and biocorrosion resistance of Mg alloy, a composite coating which composed of calcium phosphate (CaP) and collagen (Col) was successfully fabricated on the surface by chemical conversion and dip-coating methods. The chemical compositions, surface morphologies and corrosion resistance of the CaP/Col coating were investigated using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), electrochemical and immersion test. Results revealed that the collagen coating efficiently sealed the cracks and pores of CaP coating, and significantly enhanced the corrosion resistance. Furthermore, the composition of the CaP/Col coating was similar to that of bone, which can more effectively promote the adhesion, proliferation and differentiation of osteoblasts, showing excellent biocompatibility and biosafety. These observations indicated that the CaP/Col coating could protect Mg alloy from fast degradation, greatly enhance biocompatibility and osteoinductivity, and thus could be promising for orthopedic implant applications.
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•The CaP/Col composite coating was fabricated by chemical conversion and dip-coating methods.•The collagen coating efficiently sealed the pores of CaP coating and significantly enhanced the corrosion resistance.•The CaP/Col coating provided a more favorable interface for the adhesion and proliferation of osteoblasts.
Battery thermal management systems are critical for high performance electric vehicles, where the ability to remove heat and homogenise temperature distributions in single cells and packs are key ...considerations. Immersion cooling, which submerges the battery in a dielectric fluid, has the potential of increasing the rate of heat transfer by 10,000 times relative to passive air cooling. In 2-phase systems, this performance increase is achieved through the latent heat of evaporation of the liquid-to-gas phase transition and the resulting turbulent 2-phase fluid flow. However, 2-phase systems require additional system complexity, and single-phase direct contact immersion cooling can still offer up to 1,000 times improvements in heat transfer over air cooled systems. Fluids which have been considered include: hydrofluoroethers, mineral oils, esters and water-glycol mixtures. This review therefore presents the current state-of-the-art in immersion cooling of lithium-ion batteries, discussing the performance implications of immersion cooling but also identifying gaps in the literature which include a lack of studies considering the lifetime, fluid stability, material compatibility, understanding around sustainability and use of immersion for battery safety. Insights from this review will therefore help researchers and developers, from academia and industry, towards creating higher power, safer and more durable electric vehicles.
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•Performance of battery immersion cooling and different cooling fluids reviewed.•Immersion fluids can increase heat transfer by up to 10,000 times compared to air.•Thermal properties of lithium-ion batteries and heat transfer mechanisms explored.•Safety implications of battery immersion cooling discussed.•Research gaps in battery immersion cooling presented.
Athletes use cold water immersion, cryotherapy chambers, or icing in the belief that these strategies improve postexercise recovery and promote greater adaptations to training. A number of studies ...have systematically investigated how regular cold water immersion influences long-term performance and muscle adaptations. The effects of regular cold water immersion after endurance or high-intensity interval training on aerobic capacity, lactate threshold, power output, and time trial performance are equivocal. Evidence for changes in angiogenesis and mitochondrial biogenesis in muscle in response to regular cold water immersion is also mixed. More consistent evidence is available that regular cold water immersion after strength training attenuates gains in muscle mass and strength. These effects are attributable to reduced activation of satellite cells, ribosomal biogenesis, anabolic signaling, and muscle protein synthesis. Athletes use passive heating to warm up before competition or improve postexercise recovery. Emerging evidence indicates that regular exposure to ambient heat, wearing garments perfused with hot water, or microwave diathermy can mimic the effects of endurance training by stimulating angiogenesis and mitochondrial biogenesis in muscle. Some passive heating applications may also mitigate muscle atrophy through their effects on mitochondrial biogenesis and muscle fiber hypertrophy. More research is needed to consolidate these findings, however. Future research in this field should focus on
) the optimal modality, temperature, duration, and frequency of cooling and heating to enhance long-term performance and muscle adaptations and
) whether molecular and morphological changes in muscle in response to cooling and heating applications translate to improvements in exercise performance.
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