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Inorganic materials used in passive radiative cooling have achieved a commendable level of performance through synthesis, yet they lack sustainability and environmental friendliness as they do not incorporate recycling. This study developed a novel passive radiative cooling (PRC) film utilizing calcium carbonate extracted from discarded oyster shells (D-CaCO3) and polyurethane (PU) as the matrix. This sustainable approach leverages the unique properties of CaCO3, such as high solar reflectance and strong infrared emissivity, to achieve significant cooling effects. The PU/D-CaCO3 film absorbs only 22% of total solar light and exhibits a high emissivity of 95% in the atmospheric window, achieving temperatures up to 7 °C lower than the surrounding environment under 650 W/m2 solar irradiance. Furthermore, field tests were conducted to verify the implementation of our optical strategy by analyzing the optical properties and FDTD simulations. Consequently, the PU/D-CaCO3 film outperformed conventional white paint and pure PU, demonstrating a maximum temperature difference of 7 °C. Additionally, the passive radiative cooling efficiency of the film was verified through theoretical calculations. The oyster-shell-derived CaCO3 utilizes waste and contributes to carbon sequestration, aligning with sustainable and eco-friendly goals. This research demonstrates the potential of using marine-derived materials in passive cooling technologies, offering a path to reduce energy consumption and greenhouse gas emissions in cooling applications. The findings highlight the commercial viability and environmental benefits of PU/D-CaCO3 films, marking significant progress in passive radiative cooling. [ABSTRACT FROM AUTHOR]

Copyright of China Synthetic Fiber Industry is the property of Sinopec Baling Petrochemical Company and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The cooling time in injection molding is defined as the period during which the molten plastic in the mold solidifies and cools to a temperature suitable for safe ejection without deformities. Efficient cooling is crucial for large-volume production in the plastic injection molding industry. This study investigates the cooling performance of rapid tooling made from aluminum-filled epoxy resin with varying inner cooling channel surface roughness. This study includes creating a microstructure on the cooling channel surface to assess its impact on cooling efficiency. The study produces rapid tooling with both parallel and series cooling channels. The average cooling time for molded wax patterns is lower with parallel cooling channels than serial cooling channels. Nanobubble coolant shortens the cooling time of molded wax patterns based on experiments of low-pressure wax injection molding. The average cooling time-saving ratio is about 15.4% from five low-pressure injection moldings using nanobubble coolant. [ABSTRACT FROM AUTHOR]

Introduction: Amidst escalating global temperatures, increasing climate change, and rapid urbanization, addressing urban heat islands and improving outdoor thermal comfort is paramount for sustainable urban development. Green walls offer a promising strategy by effectively lowering ambient air temperatures in urban environments. While previous studies have explored their impact in various climates, their effectiveness in humid climates remains underexplored. Methods: This research investigates the cooling effect of a green wall during summer in a humid climate, employing two approaches: Field Measurement-Based Analysis (SC 1: FMA) and Deep Learning Model (SC 2: DLM). In SC 1: FMA, experiments utilized data loggers at varying distances from the green wall to capture real-time conditions. SC 2: DLM utilized a deep learning model to predict the green wall's performance over time. Results: Results indicate a significant reduction in air temperature, with a 1.5°C (6%) decrease compared to real-time conditions. Long-term analysis identified specific distances (A, B, C, and D) contributing to temperature reductions ranging from 1.5°C to 2.5°C, highlighting optimal distances for green wall efficacy. Discussion: This study contributes novel insights by determining effective distances for green wall systems to mitigate ambient temperatures, addressing a critical gap in current literature. The integration of a deep learning model enhances analytical precision and forecasts future outcomes. Despite limitations related to a single case study and limited timeframe, this research offers practical benefits in urban heat island mitigation, enhancing outdoor comfort, and fostering sustainable and climate-resilient urban environments. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LiFePO4) batteries offer preferences as well as low cost, safety, environmental compatibility, and firmness over repeated cycles. However, when subjected to high currents, this battery generates thermal issues, particularly when arranged in packs. This study aims to maintain the LiFePO4 80Ah battery within an optimal temperature range (20 °C - 40 °C) while minimising pumping power. The proposed research introduces a serpentine channel with additional branches. The design variations include a gradient in branch spacing and changes in channel width. Each design is evaluated using dimensionless parameters representing maximum temperature, temperature uniformity, pumping power, and cooling efficiency coefficient. The best design from each variation is then compared with the conventional serpentine (CS) channel design, which is well-known for its superior thermal performance. The gradient variation reduces Tmax * and T𝜎 by 0.07 and by 0.42, respectively, compared to the non-gradient channel design, at a Re 400 and a 3 C C-rate. The design with the largest channel width reduces Tmax * by 0.57 or 11.32 °C compared to the design with the smallest channel width. At a Re 1000 and 3 C C-rate, the reduction in Tmax * for the proposed channel design compared to the CS design is 0.017. In terms of the friction factor (f), the proposed design is 0.0149 lower than the CS design. The findings show that the proposed channel design outperforms the CS design in thermal performance while requiring less pumping power. [ABSTRACT FROM AUTHOR]

The uniform temperature distribution on the surface of the electromagnetic control roll (ECR) has a great impact on the quality of the strip; therefore, temperature control is essential. In order to study this issue, a two-dimensional volume of fluid (VOF) model was established using the simulation software FLUENT (2024 R1) to analyze the radial cooling capacity and surface temperature uniformity of the ECR under different process parameters, and an experimental validation was carried out at the same time. The error between the experiment and the model was less than 5% of the maximum temperature, proving the model is accurate. The results of the analysis show that the use of a controlled temperature mode has an effect on the cooling capacity and the speed has no effect on the cooling capacity. The temperature difference between the two sides of the ECR is too large, which will make the uniformity of the ECR surface temperature worse. While too high or too low, a roll speed and coolant injection speed will increase the non-uniformity of the ECR surface temperature; when the roll speed is 12 rad/s or coolant injection speed is 5 m/s, the ECR surface temperature distribution uniformity is the best. Properly adjusted process parameters can improve the cooling performance and ECR surface temperature uniformity. [ABSTRACT FROM AUTHOR]

Lithium iron phosphate (LiFePO4) batteries offer advantages such as low cost, safety, environmental compatibility, and stability over repeated cycles. However, when subjected to high currents, this battery generates thermal issues, particularly when arranged in packs. This study aims to maintain the LiFePO4 80Ah battery within an optimal temperature range (20 °C – 40 °C) while minimizing pumping power. The proposed research introduces a serpentine channel with additional branches. The design variations include a gradient in branch spacing and changes in channel width. Each design is evaluated using dimensionless parameters representing maximum temperature, temperature uniformity, pumping power, and cooling efficiency coefficient. The best design from each variation is then compared with the conventional serpentine (CS) channel design, which is well-known for its superior thermal performance. The gradient variation reduces 𝑇𝑚𝑎𝑥∗ and 𝑇𝜎 by 0.07 and by 0.42, respectively, compared to the non-gradient channel design, at a Re 400 and a C-rate 3 C. The design with the largest channel width reduces 𝑇𝑚𝑎𝑥∗ by 0.57 or 11.32 °C compared to the design with the smallest channel width. At a Re 1000 and C-rate 3 C, the reduction in 𝑇𝑚𝑎𝑥∗ for the proposed channel design compared to the CS design is 0.017. In terms of the friction factor (𝑓), the proposed design is 0.0149 lower than the CS design. The results indicate that the thermal performance of the proposed channel design is better than that of the CS design, with reduced pumping power.

Traditional ventilation duct systems for embankments in cold regions are limited in their ability to regulate ventilation, which restricts their cooling effectiveness on the subgrade. This study introduces a design method for an Intelligent Adjustment Ventilation Embankment (IAVE) system that dynamically adjusts the ventilation status within the duct based on variations in ground and air temperatures. Numerical simulations were performed to compare the cooling performance and differential settlement control of the Normal Ventilation Embankment (NVE), Temperature-Controlled Ventilation Embankment (TCVE), and IAVE systems. The results demonstrated that, compared to NVE and TCVE, the IAVE system achieved more precise temperature regulation, optimized the use of environmental cooling energy, and exhibited superior long-term cooling and differential settlement control. Among the three main factors influencing IAVE performance—ventilation duct burial spacing, burial depth, and airflow velocity—the burial spacing has the most significant impact on the Artificial Permafrost Table (APT). It not only enhances cooling during cold seasons but also effectively mitigates the re-warming of the subgrade during warm seasons. This research offers an efficient, low-carbon energy utilization structure and provides calculation results to improve the thermal stability of engineering projects in cold regions.

Copyright of Synthetic Fibre is the property of Shanghai Institute of Synthetic Fiber and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The incorporation of conformal cooling systems has significantly enhanced the efficiency and quality of injection molding process. While several automated methods have been developed for creating conformal cooling channels in injection molds, the current optimization process for conformal cooling design parameters is hindered by labor-intensive iterative thermal simulation processes and the substantial reliance on empirical human knowledge. This paper presents an innovative machine learning method to assess the thermal performance of conformal cooling systems by employing a combination of a non-linear regression model and a neural network. By employing a logarithmic regression model describing the temperature graph and a neural network predicting the coefficients of the logarithmic regression model, the thermal performance of specified conformal cooling systems can be assessed and predicted precisely. This methodology empowers designers to evaluate the thermal efficiency of conformal cooling systems efficiently and effectively to further optimize the conformal cooling design parameters without relying on tedious manual thermal and fluid simulation processes.

The incorporation of conformal cooling systems has significantly enhanced the efficiency and quality of injection molding process. While several automated methods have been developed for creating conformal cooling channels in injection molds, the current optimization process for conformal cooling design parameters is hindered by labor-intensive iterative thermal simulation processes and the substantial reliance on empirical human knowledge. This paper presents an innovative machine learning method to assess the thermal performance of conformal cooling systems by employing a combination of a non-linear regression model and a neural network. By employing a logarithmic regression model describing the temperature graph and a neural network predicting the coefficients of the logarithmic regression model, the thermal performance of specified conformal cooling systems can be assessed and predicted precisely. This methodology empowers designers to evaluate the thermal efficiency of conformal cooling systems efficiently and effectively to further optimize the conformal cooling design parameters without relying on tedious manual thermal and fluid simulation processes. [ABSTRACT FROM AUTHOR]

• A numerical model for duct-ventilated embankments driven by temperature difference is developed. • The effects of duct structure on its cooling performance are analyzed. • Ducts can greatly reduce the effect of snow thermal insulation on the cooling performance of a crushed-rock layer. In pan-Arctic permafrost regions, longitudinal ventilation ducts are often installed in embankments to cool the underlying permafrost and thereby ensure road stability. However, the current design methods for embankments with longitudinal ventilation ducts (ED) normally simplify the conjugate heat transfer process between the duct wall and air in the duct. In this study, based on the chimney effect and the theory of fluid flow and heat transfer, we propose an improved numerical method for evaluating the cooling performance of the ED. Using this method, we conduct an assessment of the influences of duct configuration on the efficiency of ventilation duct cooling in winter. The results indicate that increasing the diameter of the duct and the height of the duct outlet can effectively improve the radial cooling range of the ventilation duct. However, the cooling performance of the ventilation duct becomes worse when the length of the duct is increased. To address the limited cooling performance of the ED, we design a crushed-rock interlayer embankment installed with longitudinal ventilation ducts (CED). It is found that the CED is more effective at maintaining the long-term thermal stability of the road in a typical pan-Arctic permafrost region when compared to the ED and the crushed-rock interlayer embankment. Furthermore, a cost analysis of the four different embankment designs reveals that the CED is a financially viable option for embankment construction in permafrost regions. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental investigation into the cooling performance of a rotor-stator cavity with liquid nitrogen spraying. The experiments were conducted under varying rotational Reynolds numbers ranging from 1.70 × 106 to 5.12 × 106. The effects of rotational speed on temperature drop rate are studied and compared in detail, as well as the heat transfer coefficient distribution. Sufficient data, such as heat flux, injection rate, and injection pressure, were collected to provide a basis for further study in explaining the spray and evaporation over the cavity. It was found that the cooling performance of the rotating disc is strongly affected by the rotational speed. The short-term period exhibits a peak cooling rate of 14°C/s, in contrast to the sustained cooling rate during the spray process at rotational speeds of 500r/min, which amounts to 0.9°C/s. The occurrence of cavitation and evaporation within the nozzle results in a reduction of flow coefficient and fluctuation of the injection differential pressure. The transient cooling performance is well-explained by the temperature changes and cooling-down time under different rotational speeds. The analysis of the heat transfer coefficient is further enhanced through an evaluation of the convective and conductive heat transfer rates using a one-dimensional theoretical approach. The average temperature of the disc is expected to decrease by 100°C within a time frame no longer than 120 s. Additionally, after a duration of 120 s, the average heat transfer rate on the cold side is anticipated to surpass 8000 W/(m · K). [ABSTRACT FROM AUTHOR]

A design scheme of a static shaft turbofan engine is proposed to meet the requirements of light weight and large thrust weight ratio of small aeroengine. As the core component of stable combustion, the thermal protection problem of the mid-mounted combustion chamber is particularly prominent. This paper designs a mid-mounted combustion chamber configuration that combines gas film cooling and central combustion. The influence of structural parameters on combustion characteristics is explored by numerical simulation, and the theoretical design and numerical simulation is verified based on combustion test results. The results show that the flame shape of the mid-mounted combustion chamber conforms to the characteristics of central combustion. The combustion effect of the nozzle with spray angle of 45° and flow rate of 1.87 kg/h meets the requirements of secondary combustion of the static shaft turbofan engine, and the air inlet of the combustion liner effectively increases the thickness of the cooling gas film. The experimental results are in good agreement with the numerical simulation results, and the temperature of the combustion liner wall can be reduced effectively. The above research provides a theoretical basis for the combustion chamber design of small static shaft turbofan engines and a reference for the thermal protection methods of small aeroengine combustion chambers. [ABSTRACT FROM AUTHOR]

• A CO 2 ejector-expansion system for electric vehicles is experimentally tested. • System and ejector characteristics are investigated at 45 °C ambient temperature. • Performance improvement is evaluated compared to corresponding basic system. • Effects of EXV's opening, compressor speed, and fresh air ratio are analyzed. The ejector-expansion system design is an effective approach to improve the cooling performance of transcritical CO 2 systems. In this study, a transcritical CO 2 air-conditioning system with an ejector for electric vehicles is built up to experimentally investigate the cooling performance at an extreme temperature of 45 °C. The performance improvement is evaluated compared to the corresponding basic system. The effects of electronic expansion valve's (EXV) opening, compressor speed, and fresh air ratio are analyzed. The results show that the ejector can effectively improve system COP by 4.61–16.52 % under test conditions. At 45 °C/27 °C (out-cabin/in-cabin) condition, the optimal COP of 1.52 can be obtained at EXV's opening of 65 %. The entrainment ratio significantly goes up from 0.22 to 0.60 as EXV's opening increases. [ABSTRACT FROM AUTHOR]

The cooling performance of the energy-saving water spray window cooling system under summer conditions in Nanning city in southern China, is experimentally examined in this study. By constructing two identical test rooms for comparison, in the experiment we analyzed the effects of water temperature (22 °C, 26 °C, 30 °C), spray frequency (8, 10, 12, 15 min intervals), glass structure (single-layer, double-layer, triple-layer), air conditioning temperature (26 °C, 27 °C, 28 °C, 29 °C), and outer lamination thickness (30, 50, 100, 200 mm) on the cooling effect of windows, aiming to determine the optimal operating conditions. The experimental outcomes demonstrate that the appropriate operating mode for the water spray window system involves using the coldest water source (22 °C), with a spray interval of 8 min, a three-layer air cavity sprayed glass construction, an air cavity thickness set at 100 mm, and the best air conditioning temperature (26 °C). The study found that the water spray system can reduce the outer glass surface temperature of the window by 6 °C and the inner surface temperature by 2 °C. Moreover, the more glass layers and the thicker the lamination, the higher the energy saving rate; with a maximum energy saving rate of 35.19%. The water spray window has good adaptability and significant energy-saving effects in Southeast Asia. By scientifically selecting energy-saving glass types and fine-tuning operating modes, it is expected that efficient building energy conservation in hot climates can be achieved. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The study aimed to investigate the cooling performance of three different surgical methods for bone splitting during implant dentistry procedures. Methods: An in vitro study was conducted on bovine ribs to test the cooling performance of three osteotomy methods: conventional osteotomy with standard cooling irrigation, template-assisted osteotomy with standard cooling irrigation, and modified template-assisted osteotomy with additional cooling fluid through internal irrigation channels in the surgical guide. A negative control group without cooling was also included. Temperature measurements were taken during the procedures using a contactless infrared thermometer. Results: The results showed that the conventional osteotomy without cooling resulted in the highest mean of the peak temperatures (114.7 °C ± 45.4), while the modified template-assisted osteotomy with additional cooling achieved the lowest mean of the peak temperatures (29.4 °C ± 7). Statistically significant differences in temperature were observed among the groups (p < 0.001). Conclusion: The study rejected the null hypothesis and demonstrated that the cooling method used during bone splitting procedures significantly affected the temperature development at the surgical site. The modified template-assisted osteotomy with additional cooling provided the best cooling performance. However, caution should be exercised in interpreting the results due to the limitations of the in vitro study. Further research with stronger external validity is needed to confirm these findings and explore their applicability in clinical settings to benefit patients. [ABSTRACT FROM AUTHOR]

The widespread application of spray technology has significantly improved outdoor environmental thermal comfort. However, the spray system is unable to fulfill special comfort requirements. Utilizing mechanical ventilation and control systems effectively enhances the cooling performance of spray systems; however, those approaches are associated with elevated costs and maintenance complexities. The combination of ethanol and water has been demonstrated to produce a lower surface tension and a higher latent heat of evaporation, a property that contributes to the heat transfer efficiency and evaporation rate of the droplets. Considering the convenience and cost-effectiveness of adding ethanol as an additive, it emerges as the optimal choice. To evaluate the effectiveness of ethanol on the evaporative cooling performance of the spray system, a comparative study was conducted, comparing the cooling performances of different concentrations of ethanol with a spray system without ethanol addition. Five operating conditions were designed, including a no-spray case, a non-additive case, a 0.5 % ethanol concentration case, a 1.0 % ethanol concentration case, and a 1.5 % ethanol concentration case. The results demonstrated that adding ethanol effectively enhanced the cooling performance of the spray system. At 1.7m above ground level (0.4m away from the nozzle), compared to the non-additive case without ethanol, the 0.5 % ethanol concentration case, 1.0 % ethanol concentration case, and 1.5 % ethanol concentration case further reduced the temperature by 0.95 °C, 1.64 °C, and 2.27 °C. Moreover, the relative humidity grew by 3.57 %, 9.25 %, and 13.5 %, respectively. Adding ethanol significantly enhanced the evaporative cooling effect of the spray system, with the optimal concentration observed at 1.5 %. The results demonstrate that enhancing the evaporative cooling efficacy of a spray system by introducing ethanol into the spray medium represents a viable strategy and improve urban thermal environment in summer. Furthermore, this study aims to examine the impact of droplet evaporation on relative humidity, establishing a foundation for future enhancements aimed at addressing the issue of over-humidification in spray systems.