Hasil untuk "Heat"

J. Tewksbury, R. Huey, C. Deutsch

K. Chua, S. Chou, Wenming Yang

S. Allakhverdiev, V. Kreslavski, V. Klimov et al.

S. Harlan, A. Brazel, L. Prashad et al.

W. Mullins, R. Sekerka, J. Ball et al.

A. Zukauskas

B. Linnhoff, E. Hindmarsh

T. Voets, G. Droogmans, U. Wissenbach et al.

The mammalian sensory system is capable of discriminating thermal stimuli ranging from noxious cold to noxious heat. Principal temperature sensors belong to the TRP cation channel family, but the mechanisms underlying the marked temperature sensitivity of opening and closing (‘gating’) of these channels are unknown. Here we show that temperature sensing is tightly linked to voltage-dependent gating in the cold-sensitive channel TRPM8 and the heat-sensitive channel TRPV1. Both channels are activated upon depolarization, and changes in temperature result in graded shifts of their voltage-dependent activation curves. The chemical agonists menthol (TRPM8) and capsaicin (TRPV1) function as gating modifiers, shifting activation curves towards physiological membrane potentials. Kinetic analysis of gating at different temperatures indicates that temperature sensitivity in TRPM8 and TRPV1 arises from a tenfold difference in the activation energies associated with voltage-dependent opening and closing. Our results suggest a simple unifying principle that explains both cold and heat sensitivity in TRP channels.

B. Finlayson

W. Rohsenow

A method based on a logical explanation of the mechanism of heat transfer associated with the boiling process is presented for correlating heat-transfer data for nucleate boiling of liquids for the case of pool boiling. The suggested relation is clTxhfg=Csf(q/Aμlhfg(q/A)σg(ρl-ρv))0.33(clμlkl)1.7 where the various fluid properties are evaluated at the saturation temperature corresponding to the local pressure and Csf is a function of the particular heating surface-fluid combination.

I. Marai, A. El-Darawany, A. Fadiel et al.

M. Planck

Mahyar Ashouri, Majid Bahrami

W. Bastiaanssen

Xianyao Chen, K. Tung

Shihao Han, Liancun Zheng, Chunrui Li et al.

Dachaphon Kealkaew, Ahmad Fazlizan, Atthakorn Thongtha

Unplasticized Polyvinyl Chloride roofing systems through strategic Phase Change Material integration. The experimental design employed two distinct of Phase Change Material with melting points near 45 °C (referred as PCM1) and 55 °C (referred as PCM2). Standardized cubic test specimens measuring 60 cm × 60 cm × 60 cm were constructed to evaluate three configuration scenarios: Phase Change Material placement directly beneath the Unplasticized Polyvinyl Chloride roof, Phase Change Material sandwiching between the Unplasticized Polyvinyl Chloride roof and gypsum board substrate, and Phase Change Material positioning above the gypsum board layer. Controlled thermal testing was conducted at constant temperatures of 40 °C, 50 °C, and 60 °C, with each condition maintained for 240-minute durations using consistent heat sources. Results demonstrated optimal thermal performance when Phase Change Material was strategically positioned between the Unplasticized Polyvinyl Chloride roofing and gypsum board configuration. Comparative analysis between Phase Change Material formulations revealed Phase Change Material type 2′s superior heat transmission reduction capabilities, achieving temperature decreases of approximately 1.0 °C, 1.2 °C, and 1.3 °C ± 0.05 °C at the respective test temperatures compared to non-Phase Change Material type 2 integrated systems. Field validation over three days confirmed Phase Change Material type 2′s effectiveness, maintaining interior temperatures at 42.3 °C ± 0.05 °C, representing a 4.3 % reduction compared to conventional Unplasticized Polyvinyl Chloride roofing without Phase Change Material integration. Additionally, Phase Change Material type 2 installation exhibited extended heat flux time delays and reduced decrement factors, making it particularly suitable for residential roofing applications in Thailand’s tropical climate conditions.

Farrag F. B. Abu-Ellail, Noran A. M. Bassiony, Ramy N. F. Abdelkawy

Abstract Background Using vital amino acids, such as proline, helps the sugar beet and benefits plants that grow in harsh and saline soil. Saline soil stress has a negative effect on both root and sugar yield. Methods To lessen the negative impacts of salinity, six monogerm sugar beet varieties were assessed with varying proline concentrations during the 2022–2023 and 2023–2024 seasons. Across two growing seasons, six sugar beet varieties— Smart Meyra, Smart Seza, BTS3740, BTS3880, Wombat Smart, and SV2003—were cultivated in subplots, while proline levels (zero, 50, 100, and 200 ppm) were administered in the main plots. Results BTS3880 and Smart Seza exhibited the highest mean values for quality attributes, whereas Smart Meyra and Smart Seza emerged as elite varieties with superior growth and yield traits. Sugar beet root yield showed a positive association with root length, root diameter, root fresh weight/plant, top fresh weight, sucrose, extractable sugar, and total sugar yield; in contrast, the sugar yield was negatively correlated with potassium (K), sodium (Na), alpha-amino (N), and sucrose loss to molasses (SLM). The findings showed that only three of the twelve principal components (PCs) demonstrated 95.6% variability between the characteristics under study. Selecting key traits that enhance sugar yield under PC1 may be beneficial, as PC1 showed the most significant variation. Conclusion It is possible to obtain high yield and quality sugar characteristics by spraying sugar beet varieties with a 200 ppm proline concentration. Smart Meyra and Smart Seza were the top-performing varieties, exhibiting high values (as a mean) for growth, yield, and quality traits.

M. R. Du, T. D. Xuan, Z. F. Chen et al.

Abstract This study developed a novel high-brisance emulsion explosive containing sodium borohydride (NaBH4). The effects of NaBH4 content on the performance of the emulsion explosive were investigated using methods such as brisance, detonation velocity, air shock wave analysis, density measurement, and theoretical calculations. And the thermal decomposition characteristics of emulsion explosives samples were investigated using thermogravimetric (TG) experiments. The results indicate that as the NaBH4 content increases, the explosive density initially increases and then decreases, the detonation velocity gradually decreases, the explosive heat continuously increases, and the explosion volume first increases slightly and then decreases. Brisance, influenced by multiple factors including density, detonation velocity, explosive heat, and explosion volume, also shows a trend of first increasing and then decreasing. When the NaBH4 content is 5%, the brisance reaches its maximum value (26.3 mm), representing a 66.5% improvement compared to conventional emulsion explosives and surpassing existing high-brisance emulsion explosives. Furthermore, with increasing NaBH4 content, the peak overpressure of the air shock wave initially decreases and then increases. The TG and derivative thermogravimetry (DTG) curves of all samples exhibit consistent trends. Under the same heating rate, the addition of NaBH4 raises the initial decomposition temperature of the emulsion explosive.

Mahdi Taheri, Sepehr Shahgholian, Mehdi Jahangiri et al.

In this study, the feasibility of providing part of the hot water using 1000 flat-plate solar collectors for the Hawana Water Park in Salalah, Oman, is studied. Dynamic analyses of energy, economic, and environmental parameters are conducted over a year using TSOL V2021 software. In this solar energy–supported hot water production system, a gas-fired boiler is also used as a backup for emergencies. The results indicate that approximately 1181 MWh of solar heat is supplied annually to the water park, leading to a savings of 133,298 m3 of natural gas and preventing the emission of approximately 282 tons of CO₂ pollutants. Another significant finding is that the solar water heating system, with an efficiency of 56.6%, was able to supply 30.4% of the heat required by the water park. The cost of each kilowatt-hour of solar heat produced is calculated to be $0.066, with a payback period of 15.2 years. Furthermore, eight sensitivity scenarios were evaluated to investigate the impact of carbon credit trading and energy price increases on the economic performance of the assessed system. The results indicate that by integrating carbon pricing mechanisms, such as the Emissions Trading System (ETS), the cost of energy (COE) can be reduced by up to $0.026 per kWh, and the payback period can be shortened to 8.4 years. Moreover, the return on assets (ROA) significantly improves under scenarios involving higher carbon credit prices and rising energy costs, highlighting the economic and environmental benefits of integrating renewable energy systems with emerging carbon markets.