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The problem of thermally induced defects in power equipment is prominent, affecting the safe and stable operation of the power grid. To detect abnormal heating in time, a reversible temperature-indicating patch measurement for temperature self-detection of power equipment is proposed, and its performance is analyzed and studied. The results show that the reversible thermochromic patch prepared with heat-sensitive red as the hidden colorant, dodecyl gallate as the color rendering agent, and tetradecane as the solvent has the color change characteristic of “light color at low temperature and deep color at high temperature”, and its color-changing temperature interval is 42°C ∼ 52°C. The color-changing performance of the materials with different quality ratios is different, from which the optimal ratio of the color-changing materials is selected as thermochromic red: lauryl gallate: tetradecanol=1:7:30. To facilitate the application of the color-changing materials on-site, the color-changing materials are encapsulated by melt adsorption sealing technology, and the temperature indicating patches with good color-changing reversibility are prepared. The research results can provide a reference for the field application of reversible color-changing materials for temperature self-detection of power equipment.

Interfacial microbial degradation of alkane in Pickering emulsions stabilized by hydrophobic bacterial cells is a new mechanism for microbial degradation of water-insoluble chemicals, where both water-insoluble chemicals in the oil phase and water-soluble nutrients (such as nitrogen and phosphorus) in the water phase are bio-accessible to living microorganisms anchoring onto the oil–water interfaces. In the present work, super-hydrophobic Mycobacterium sp. (contact angle 168.6°) degradation of tetradecane was set up as a model. Addition of fumed SiO2 particles (Aerosil® R974) as a new strategy was developed to enhance tetradecane degradation where the biodegradation rate (based on the accumulated biomass) increased by approximately 80%. The enhanced effect of SiO2 particles on the tetradecane degradation attributed to the synergistic effect of SiO2 particles on the emulsion efficiency of Pickering emulsions stabilized by bacterial cells and then on the enhancement of interfacial microbial degradation in Pickering emulsions.Key points• Interfacial microbial degradation in bacterial cells stabilized Pickering emulsions.• Adding fumed SiO2 particles to enhance microbial degradation of tetradecane.• Correlation relationship between emulsion efficiency and interfacial microbial degradation.

A capsule phase-change material (CPCM) was synthesized using n-tetradecane as the core, expanded graphite as the shell, and ethyl cellulose as the coating material through a controlled assembly process. The results demonstrate that the infiltration of n-tetradecane significantly enhances the density of the expanded graphite, while the ethyl cellulose coating effectively prevents the desorption and leakage of the liquid phase-change material during phase transitions. As a result, the CPCM exhibits a compact structure, chemical stability, and excellent thermal stability. The incorporation of this CPCM into cement-based materials endows the material with an autonomous heat-release capability at temperatures below 5[degrees]C. When the CPCM content reaches 20%, the thermal conductivity of the cementitious matrix increases by 24.66%. Moreover, the CPCM significantly improves the freezing-and-thawing resistance of the cement-based materials, reducing the compressive strength loss by 96% and the flexural strength loss by 65% after freezing-and-thawing cycles. This CPCM fundamentally enhances the frost resistance of cement-based materials, addressing the issue of freezing-and-thawing damage in concrete structures in cold regions. Keywords: capsule phase-change material (CPCM); cement-based materials; expanded graphite; frost resistance; n-tetradecane.

A high-temperature and high-pressure optical cell VLE apparatus has been applied to measure phase equilibrium properties of n -tetradecane in the supercritical binary solvent (0.367propane + 0.633 n -butane mass fraction) at temperatures of 413.15 K, 433.15 K, and 453.15 K between of pressures (0.9 and 6.6) MPa. The combined expanded uncertainty of the temperature, pressure, and concentration measurements at 0.95 confidence level with a coverage factor of k  = 2 is estimated to be 0.15 K, 0.0022, and 0.035, respectively. The critical parameters ( T C , P C , w C ) were determined based on the measured isothermal phase equilibrium data of the ternary system n -tetradecane + propane/ n -butane. It is shown that the critical temperature and pressure of the n -tetradecane + propane/ n -butane system increases with concentration of n -tetradecane increases.

The fragmentation of normal alkanes during the cracking of oil under geochemical conditions with high thermal stress is important for the preservation of crude oils in reservoirs and the formation of gaseous hydrocarbons. In this study, the kinetics behavior, cracking mechanisms, and products of n-tetradecane pyrolysis were investigated using reactive molecular dynamics (ReaxFF MD) simulations at high temperatures (2000K∼3000 K). The pyrolysis process itself, its main products and intermediates, and kinetic behavior were analyzed at an atomic/molecular level. Low molecular weight (C1–C5) alkanes and olefins, together with H2, were the predominant intermediates and products of the simulations. Three distinct stages—a stable stage, initial decomposition, and secondary pyrolysis—can be distinguished during the decomposition process. The reactant n-tetradecane was exhausted when the simulation temperature reaches ∼2250 K, accompanied by a rapid increase in hydrocarbons with molecular numbers C1–C5. The yield of C2–C5 peaked at ∼2500 K and then decreased. The number of CH4 molecules increased continuously throughout the entire simulation process because of the contribution of secondary pyrolysis. The Arrhenius parameters obtained from ReaxFF MD simulations, on the basis of first-order kinetic analysis of n-tetradecane, were reasonably consistent with experimental data and generally in agreement with results from pyrolysis experiments on crude oils in the laboratory. The pyrolysis process and reaction mechanism of n-tetradecane were also reasonably consistent with laboratory pyrolysis experiments on whole oils and their individual components. ReaxFF molecular dynamics simulation is therefore considered to be a valid approach for the study of thermal cracking of subsurface crude oils.

As an essential agroforestry, intercropping legumes can improve the physical, chemical, and biological fertility of the soil in tea plantations. However, the effects of intercropping different legume species on soil properties, bacterial communities, and metabolites remain elusive. In this study, the 0-20 cm and 20-40 cm soils of three planting patterns (T1: tea plants/mung bean intercropping, T2: tea plants/adzuki bean intercropping, T3: tea plants/mung bean and adzuki bean intercropping) were sampled to explore the diversity of the bacterial community and soil metabolites. The findings showed that, as compared to monocropping, intercropping systems had greater concentrations of organic matter (OM) and dissolved organic carbon (DOC). Notably, pH values were significantly lower, and soil nutrients increased in intercropping systems compared with monoculture in 20-40 cm soils, especially in T3. In addition, intercropping resulted in an increased relative abundance of Proteobacteria but a decreased relative abundance of Actinobacteria . 4-methyl-Tetradecane, acetamide, and diethyl carbamic acid were key metabolites mediating the root–microbe interactions, especially in tea plants/adzuki intercropping and tea plants/mung bean, adzuki bean mixed intercropping soils. Co-occurrence network analysis showed that arabinofuranose, abundant in tea plants and adzuki bean intercropping soils, showed the most remarkable correlation with the soil bacterial taxa. Our findings demonstrate that intercropping with adzuki beans is better at enhancing the diversity of soil bacteria and soil metabolites and is more weed-suppressing than other tea plants/legume intercropping systems.

The purpose of this study was to determine the possibility of obtaining liquid paraffins on the basis of by-products available in the local chemical industry, and to compare the product with industrial apolar wound agents in the process of silvinite flotation. The experiments were performed with a secondary liquid product - hexane solution and pyrocondensate. A technological sequence of reagent use to increase the efficiency of the flotation process is proposed. In order to increase the efficiency of the flotation process, the sequence of transfer of reagents to the process and the time of exposure were studied. Experiments have shown that adding 2.5 to 7.5% tetradecane and pentadecane to liquid paraffins derived from hexane used can reduce KCl residue by 2.2%. The technology producing of local liquid paraffins from hexane, a secondary product of Uz-Kor Gas Chemical JV LLC, has been developed.

Icing is a common physical phenomenon, and the icing of wind turbine blades can significantly affect the performance of wind turbines. Therefore, researching methods to prevent icing is of great significance, and the coating method of anti-icing is an effective way to delay icing, with advantages such as low energy consumption and easy implementation. In this study, using the coating method as the background, tetradecane phase change microcapsules were prepared, with a melting enthalpy of 90.8 J/g and a crystallization enthalpy of 96.3 J/g, exhibiting good coverage and energy storage efficiency. After mixing tetradecane phase change microcapsules (PCMS) with polyurethane coating (PUR) and coating them on wind turbine blades, after a 5 min icing wind tunnel test, the coating could significantly delay the icing on the blade surface, with the highest anti-icing rate reaching 60.41%. This indicates that the coating has a good anti-icing effect and provides basic research data for exploring new anti-icing methods.

Rhodococcus sp. strain p52, an aerobic dioxin degrader, was capable of utilizing petroleum hydrocarbons as the sole sources of carbon and energy for growth. In the present study, the degradation of the mixture of aliphatic hydrocarbons (hexadecane and tetradecane) and aromatic hydrocarbons (phenanthrene and anthracene) by strain p52 was examined. The results showed that the degradation of phenanthrene was enhanced in the presence of hexadecane or tetradecane due to increased bioavailability and improved cell surface hydrophobicity, which facilitated better substrate uptake. Conversely, the degradation of hexadecane and tetradecane decreased in the presence of aromatic hydrocarbons, likely due to the cometabolic effect, metabolic regulation, substrate competition, and the shift in enzyme activity. Moreover, the removal of 4.4 g L−1 diesel fuel, a complex mixture of aliphatic hydrocarbons and aromatic hydrocarbons, was investigated and 63.7% of oil contents were depleted within 96 h. Therefore, strain p52 showed the potential to remove petroleum pollutants.

Strong compression of the medium in cavitation bubbles during their collapse in acetone at temperatures of 273 and 293 K and tetradecane at a temperature of 663 K is considered. The features of the behavior of the maximum values of the thermodynamic parameters in the case of the formation of converging shock and isentropic compression waves inside the bubbles in wide ranges of the liquid pressures are studied. The influence of the shock and isentropic waves and their mutual interaction on the level of the maximum values of the thermodynamic parameters attained inside the bubbles is illustrated.