Thermo

The present study aims to experimentally investigate pool boiling heat transfer characteristics, such as critical heat flux (CHF) and boiling heat transfer coefficient (BHTC), of pure distilled water (d-H₂O) and functionalised graphene nanoplatelet (f-GnPs)–d-H₂O nanofluids using a nichrome (Ni-Cr) test wire as the heating element. The distilled water (dH₂O) and GnP (5–10 nm and 15 µm, Cheap Tubes, USA) were chosen as the base fluid and nanomaterial, respectively. The GnP was chemically functionalized and dispersed in dH₂O using a probe sonicator. The nanofluids were characterized by measuring the zeta potential distribution and pH to ensure stability on day 1 and day 10 following preparation. The results show that the zeta potential values range from −31.6 mV to −30.6 mV, while the pH values range from 7.076 to 7.021 on day 1 and day 10, respectively. The novelty of the present study lies in the use of f-GnPs with a controlled size and stable nanofluid, confirmed through zeta potential and pH analysis, to determine the heat transfer behaviour of a Ni-Cr test wire under pool boiling conditions. The pool boiling heat transfer characteristics, such as CHF and BHTC, were observed using the fabricated pool boiling heat transfer test facility. Initially, the dH₂O and f-GnP–dH₂O nanofluids were separately placed in a glass container and heated using a pre-heater to reach their saturation point of 100 °C. The electrical energy was gradually increased until it reached the critical point of the Ni-Cr test wire, i.e., the burnout point, at which it became reddish-yellow hot. The CHF and BHTC were predicted from the experimental outputs of voltage and current. The results showed an enhancement of ~15% in the CHF at 0.1 vol% of f-GnPs. The present study offers a method for enhancing two-phase flow characteristics for heat pipe applications.

Coal-to-Synthetic Natural Gas (SNG) plays a crucial role in China’s decarbonization strategy but faces significant sustainability challenges due to its carbon-intensive nature. This study integrates Life Cycle Assessment (LCA) with Box–Behnken Design and Response Surface Methodology (BBD-RSM) to quantify and optimize key parameters for emission reduction. The LCA results indicate that 90.48% of total emissions originate from the SNG production stage, while coal mining accounts for 9.38%, leading to a carbon intensity of 660.92 g CO₂^eq/kWh, second only to conventional coal power. Through BBD-RSM optimization, the optimal parameter combination was identified as a raw coal selection rate of 62.5%, an effective calorific value of 16.75 MJ/kg, and a conversion efficiency of 83%, corresponding to an energy-based rate of return (ERR) of 49.79%. The optimized scenario demonstrates a substantial reduction in total life-cycle emissions compared with the baseline, thereby improving the environmental viability of coal-to-SNG technology. Furthermore, this study employs the energy-based rate of return (ERR) as a normalization and comparative evaluation metric to quantitatively assess emission reduction potential. The ERR, combined with BBD-RSM, enables a more systematic exploration of emission-driving factors and enhances the application of statistical optimization methods in the coal-to-SNG sector. The findings provide practical strategies for promoting the low-carbon transformation of the coal-to-SNG industry and contribute to the broader advancement of sustainable energy development.

When it comes to developing new titanium alloys for biomaterials, β metastable alloys have been gaining the most attention from researchers, as they have a lower elastic modulus and the microstructure can be altered by adding other elements and heat treatments (HT), which makes the material a promising biomaterial. The Ti-10Mo-Mn alloys were melted in an arc furnace. After ingot casting, a homogenization treatment (#T) was carried out, followed by the mechanical processing of hot rolling (#1) and subsequent annealing HT (#2). This work aimed to analyze the influence of some HT on the phase constituents, percentages, morphologies, distributions and selected mechanical properties, such as microhardness and elastic modulus in Ti-10Mo-xMn system alloys, ranging from 0 to 8% by weight. The results showed that alloys with low manganese content, classified as metastable, were sensitive to the HT in this study. From 4% manganese, the alloys had a stable β phase and were, therefore, not sensitive to the HT. The hardness of the alloys with 0 and 2% manganese remained high, possibly due to the presence of the omega phase. The elastic modulus increased from the hot rolling condition (#1) to annealing condition (#2) in all compositions. The Ti-10Mo-2Mn#1 alloy stood out among the alloys studied. It showed the lowest elastic modulus (~87 GPa), making it suitable for use as a biomaterial.