Efficient Heat Research Articles

Investigation on the Heating Effects of Intra-Tumoral Injectable Magnetic hydrogels (IT-MG) for Cancer Hyperthermia.

Capacitive-based radiofrequency (Rf) radiation at 27 MHz offers a non-invasive approach for inducing hyperthermia, making it a promising technique for thermal cancer therapy applications. To achieve focused and site-specific hyperthermia, external material is required that efficiently convert Rf radiation into localized heat. Nanomaterials capable of absorbing Rf energy and convert into heat for targeted ablation are of critical importance. In this study, we developed and evaluated an intra-tumoral injectable magnetic hydrogel (IT-MG) composed of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) impregnated in low molecular weight Hyaluronic Acid (HA) forming HA-SPIONs. Our systematic investigation revealed that HA-SPIONs exposed to Rf radiation produced significant temperature increases, reaching up to 50 °C. Further testing in tissue-mimicking phantom models showed consistent heating, with temperatures stabilizing at 43oC, ideal for localized hyperthermia. The ability of HA-SPIONs to act as an efficient localized heating agent when exposed to 27 MHz Rf radiation, reaching apoptosis-inducing temperature has not been previously reported. In conclusion, synergistic effects of IT-MG in both in-vitro and tumour mimicking phantom model demonstrates improved and localized hyperthermia facilitating adjuvant cancer treatment. &#xD.

A field study on thermal comfort and adaptive behaviour of university open-plan offices in severe cold regions of China

ABSTRACT This study investigates the thermal comfort and adaptive behaviours of occupants in open-plan office spaces at a university located in Northeast China, a region characterized by severely cold winters with an average temperature ≤−10°C in the coldest month. The research focuses on the interaction between buildings and occupants from an indoor environmental quality perspective, contributing to the field of occupant-centric building design and operation by studying thermal comfort, adaptive behaviour, and energy-efficient heating strategies in severe cold regions. By employing field measurements and a subjective questionnaire survey, we summarized the environmental factors contributing to thermal discomfort and their respective weights. The results reveal that air temperature, radiant asymmetry caused by envelopes, and relative humidity are the three most significant factors, with weights of 0.376, 0.209, and 0.194, respectively. Furthermore, a fuzzy comprehensive evaluation method was employed to determine the thermal neutral operating temperature (22.5°C) and the acceptable operating temperature range (19.5°C to 25.5°C). Based on the analysis of occupant behaviour characteristics and preferences, a suitable winter heating setting is proposed for open-plan university offices. These findings support the development of more accurate building performance simulations and inform strategies for low-energy building management in severe cold regions.

Thermal Diode Films with Liquid Crystal Elastomer Microstructures

Thermal diodes enabling asymmetric heat flow via efficiently conducting heat in one direction while blocking it in the opposite direction have great potential for controlling and managing thermal energy. Here, a thermal diode film with a scalable and thin‐film form factor is presented, which utilizes thermal contact asymmetry that varies with the direction of heat flow. The proposed thermal diode film is fabricated using two liquid crystal elastomer (LCE) layers separated by an air gap: one surface has a pillar structure, and the other has a hexagonal honeycomb structure. In forward mode, heating the LCE layer with the hexagonal honeycomb structure causes the sidewalls to buckle and contact the pillar structure on the opposite side, facilitating efficient conductive heat transfer. In reverse mode, heating the LCE layer with a pillar structure causes it to contract, increasing the gap between the layers with the pillar and hexagonal structures. This increased gap reduces convective heat transfer across the air gap. The thermal contact asymmetry, depending on the direction of heat flow, enables the film to achieve a thermal rectification ratio of ≈2.0 over a wide temperature range of 60–100 °C.

Development of New Composite Beds for Enhancing the Heat Transfer in Adsorption Cooling Systems

Adsorption chillers are distinguished by their low electricity consumption, lack of moving parts and exceptional reliability. However, their considerable weight, due to the low sorption capacity of conventional adsorbents, remains a key limitation. This study investigates the effect of introducing thermally conductive additives—aluminium powder, copper powder and graphite flakes—at 5, 15 and 25 wt.% to silica-gel-based adsorbent beds on the enhancement of heat transfer. In contrast to other works, this study also includes a novel analysis of the thermal properties of dry sorbents, since the moisture content affects the thermal conductivity. Additives improve the thermal conductivity, as measured by the laser flash method (LFA), of the bed by up to 20.7% while maintaining a reasonable sorption capacity, as measured by the dynamic vapor sorption (DVS). Additions of copper at 5–15 wt.% and graphite flakes at 15–25 wt.% provide an optimal compromise between thermal conductivity and sorption capacity. Aluminium powder, on the other hand, offers flexibility over a wider range (5–25 wt.%). The increased thermal conductivity of these modified materials is expected to lead to more efficient heat transport, which suggests the hypothesis that it could reduce the cycle time and increase the efficiency of adsorption chillers.

Self‐Attachable and Conductive Hydrogel Adhesive Patch

ABSTRACTHydrogels have emerged as promising materials for flexible and wearable devices due to their mechanical softness and biocompatibility. However, conventional hydrogels often fail to combine multiple essential functions, such as reusable dry adhesion, strong wet adhesion, and electrical conductivity. Here, we present a multifunctional hydrogel patch that integrates polyethylene glycol dimethacrylate (PEGDMA) with poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS). The hydrogel features bioinspired mushroom‐shaped micropillars that adapt to target surfaces. This design achieves exceptional adhesion strength on both dry (129.2 kPa) and wet surfaces (116.3 kPa), maintaining its performance through 300 cycles. By incorporating PEDOT:PSS into the PEGDMA network, we significantly enhance the electrical conductivity, enabling effective Joule heating. The micropillar architecture ensures uniform contact with various surfaces, leading to efficient heat transfer. This hydrogel patch represents a significant step forward in flexible and wearable technologies by combining mechanical flexibility, electrical and thermal conductivity, and robust, reversible adhesion in a single material.

Structural, morphological and biological assessment of magnetic hydroxyapatite with superior hyperthermia potential for orthopedic applications

Hydroxyapatite (HA) is an important constituent of natural bone. The properties of HA can be enhanced with the help of various ionic substitutions in the crystal lattice of HA. Iron (Fe) is a vital element present in bones and teeth. In this study, iron-doped HA was synthesized using a refluxing-based sol-gel route with varying concentrations of iron (1–9 M%). Samples were analyzed using an X-ray diffractometer (XRD), UV–Vis Spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM) and Scanning Electron Microscope (SEM). The biological assessment was carried out by hemolytic assay, anti-bacterial activity and in-vitro biocompatibility. XRD data confirmed the evolution of the hexagonal HA crystal structure with the reduction in the crystallinity and the crystallite size. All the characteristic bands were confirmed using FT-IR which also further proved the existence of A-type carbonated apatite. The UV–Vis spectra confirmed the reduction in the band gap energies owing to the substitution of iron. The SEM results showed a change in the shape of the samples with increasing iron concentration. The magnetic behavior of samples also altered from diamagnetic to ferromagnetic behavior due to the doping of iron with enhanced heating efficiency. All the samples were found to be hemocompatible. The antibacterial efficacy was found to be higher for E. coli (gram-negative) bacteria compared to S. aureus (gram-positive) bacteria. Moreover, the superior cell viability of MG-63 (osteoblast-like) cells was observed in Fe-doped HA, attributed to MTT assay which revealed the enhanced cell viability of osteoblast-like cells in the Fe-doped HA. These results strongly emphasize the potential of the developed samples for bone regeneration applications.

Effects of naked neck and frizzle genes on growth and egg-laying performance of chickens in the tropics in an era of climate change.

In regions characterized by tropical and subtropical climates, the elevated ambient temperatures exert adverse effects on both broiler and laying chickens, impacting their growth and egg production performance. To mitigate the challenges posed by heat stress, genetic strategies aimed at reducing feather coverage have gained prominence in hot climate areas. Among these approaches, the naked neck (Na) and frizzle (F) genes have emerged as particularly noteworthy. The Na and F genes play a pivotal role in facilitating heat dissipation and temperature regulation. By decreasing feather insulation, these genes enable efficient heat dissipation through exposed areas of the chickens' bodies. This reduction in feather coverage leads to elevated body surface temperature, which, in turn, enhances the capacity for heat loss and contributes to overall body temperature reduction. A substantial body of literature underscores the well-established positive impacts of the naked neck and frizzle genes on growth and egg-laying performance. As a result, these genes hold significant potential for integration into broiler and layer production systems, especially in regions characterized by high tropical temperatures. In the context of broiler farming under challenging heat conditions, the Na and F genes have demonstrated favorable effects on crucial parameters such as feed conversion ratio, body weight gain, disease resistance, and carcass attributes. Likewise, layers exposed to elevated temperatures exhibit enhanced egg production, eggshell quality, fertility, hatchability, and resistance to diseases when these genesare incorporated. Given that the prevalence of the naked neck and frizzle genes is primarily observed in indigenous chicken populations, it becomes imperative to prioritize measures for their conservation due to their exceptional performance in heat-stressed environments. To unlock the full genetic potential of exotic poultry reared in hot and humid conditions, the integration of the Na and F genes is a strongly recommended strategy.

Control Parameters of a Wall Heating and Cooling Module with Heat Pipes—An Experimental Study

Heat pipes filled with a thermodynamic medium are energy-saving and stable heat exchangers that have been used for years in various fields of science and technology, including building heating and cooling installations. This article presents the results of research on the energy efficiency of wall-mounted concrete heating and cooling modules with heat pipes, which can be a structural element of external and internal walls of buildings for various purposes. A series of measurement tests were performed, which allowed the determination of how the thermal power and control parameters of the module (amplification factor and time constants) change under operating conditions. A first- and second-order inertial model was used to describe the control properties of the module. The measurements were performed in heating and cooling mode for three different values of supply water flow, both when increasing the supply temperature and when decreasing it. Based on the results of the measurements, calculations and analysis, it was found that the thermal power and control parameters of the module change significantly; these changes result from both the design features of the module (the type of thermodynamic medium in the heat pipe and the technical aspects of the execution and assembly of the connections between the collector and the heat pipe) and the operating conditions (the value of the direction of temperature change and the flow of the supply water). It was shown that the supply temperature has a much greater impact on the values of the module’s control parameters than the flow rate of the supply water. The tested module is characterized by slow changes in temperature on its surface (high values of time constants). The time of stabilization of the temperature on the module’s surface, after step forcing, is 8–10 h. This can cause greater fluctuations in the indoor air temperature, lower thermal comfort in the room and lower energy efficiency of the process. These issues can be prevented by using complex algorithms for thermal comfort control, which in turn increase the cost of the control system.

A Review of Defrosting Technologies for Air Source Heat Pumps

Air source heat pumps (ASHPs) are widely used in building energy efficiency due to their high performance and environmental benefits. However, in cold climates, frosting of ASHP evaporators during winter operation reduces heating efficiency, affects user comfort, and may even cause system shutdowns or permanent damage. Therefore, optimizing the defrosting cycle, implementing intelligent frost control, and accurately detecting frost thickness are key challenges in both research and practice. This paper reviews recent advancements in defrosting technologies for ASHPs, focusing on the limitations of existing methods and the development of emerging technologies. It also discusses intelligent control strategies, with an emphasis on intelligent frost detection and control systems. Finally, the paper outlines the future trends in ASHP defrosting technologies, aiming to provide a theoretical and technical foundation for their innovation and improvement.

Insights into the effects of biomass feedstock and pyrolysis conditions on the energy storage capacity and durability of standard biochar-based phase-change composites

Material selection and production conditions are imperative for determining the functional performances of composite materials. Phase-change composites obtained from phase-change materials (PCMs) and supporting matrices exhibit high thermal energy storage density. They are used to overcome the intermittency issues of wind and solar energy, as well as to reduce waste heat dissipation to the environment. However, the large-scale utilization of composite and pristine materials has severe drawbacks, primarily stemming from the complex fabrication routes of the encapsulating agents, leakage, and inadequate thermal stability. In this study, biochar-based phase-change composites were fabricated using vacuum infiltration techniques, and the effects of biomass feedstock and pyrolysis temperature on the performance of the composite were elucidated using different types of biowastes and temperatures. This approach has several advantages, including facile production techniques, low-cost carbon sources, and environmental friendliness. The PCM adsorption ratio of biochars derived from rice husk (RH) and Miscanthus straw linearly correlated with the pyrolysis temperature (550–700 °C), while RH700 resulted in a composite with a high enthalpy per unit mass of hexadecane (HXD) in RH700/HXD (250.9 J g−1) owing to the high surface area of RH700 (74.66 m2 g−1). The crystalline temperature increased slightly from 10.7 °C in RH550/HXD to 10.9 °C in RH700/HXD, suggesting improved molecular motion and crystal growth of HXD. Wheat straw biomass pyrolyzed at a low temperature (550 °C), displaying a reduced surface area at 700 °C (7.35 m2 g−1) and exhibiting the lowest energy storage density. The latent heat efficiency reached 99.5–100%, where RH700/HXD exhibited 100% efficiency. The composites demonstrated strong leakage resistance at high heating temperatures (60 °C, above the melting temperature of HXD), good chemical compatibility between the biochar and HXD, and high durability after 500 thermal cycles. Therefore, the extent of PCM loading and energy storage density improvements primarily depends on the pyrolysis conditions, feedstock used, and pore size distribution of the biochar samples. This research provides insights into the fabrication of phase-change composites and optimization of the carbonization process of different biomasses used for thermal management applications, such as building energy savings.Graphical

Numerical Simulation of Airflow Organization in Vulcanization Tanks for Waste Tires.

Currently, in the domestic practice of retreading tires using vulcanization tanks, some tanks exhibit uneven temperature distributions leading to low retreading success rates. To address that, this paper simulated the temperature and velocity fields during the heating process of vulcanization tanks for waste tire retreading. The results indicated that a higher heating power reduces the time required for the vulcanizing agent to reach the vulcanization condition, but it also increases the difference in tire temperature in the tank, with a severely uneven distribution of the temperature field. Subsequently, to improve the uniformity of temperature distribution and enhance the retreading rate of waste tires, this paper proposed two types of orifice plates to adjust the airflow organization. The results show that both the plain orifice plate and the frustum cone orifice plate can enhance the uniformity of the temperature field within the vulcanization tank and reduce the temperature difference between tires. Moreover, at the same heating power, the presence of the orifice plates increases the rate of temperature increase in the tires and the vulcanizing agent compared to the original vulcanization tank, improving the thermal efficiency of the vulcanization tank heater.

MXene Hollow Microsphere-Boosted Nanocomposite Electrodes for Thermocells with Enhanced Thermal Energy Harvesting Capability.

Thermal energy, constantly being produced in natural and industrial processes, constitutes a significant portion of energy lost through various inefficiencies. Employing the thermogalvanic effect, thermocells (TECs) can directly convert thermal energy into electricity, representing a promising energy-conversion technology for efficient, low-grade heat harvesting. However, the use of high-cost platinum electrodes in TECs has severely limited their widespread adoption, highlighting the need for more cost-effective alternatives that maintain comparable thermoelectrochemical performance. In this study, a nanocomposite electrode featuring Ti3C2Tx with hollow microsphere structures is rationally designed. This design addresses the restacking issue inherent in MXene nanosheets, increases the electrochemically active surface area, and modifies the original MXene surfaces with oxygen terminations, leading to improved redox kinetics at the electrode-electrolyte interface, particularly in n-type TECs employing Fe2+/3+ redox ions. The optimized n-type TEC achieved an output power of 84.55 μW cm-2 and a normalized power density of 0.53 mW m-2 K-2 under a ΔT of 40 K, outperforming noble platinum-based TECs by a factor of 5.5. An integrated device consisting of 32 TEC units with a p-n connection is also fabricated, which can be successfully utilized to power various small electronics. These results demonstrate the potential of MXene-based composite electrodes to revolutionize TEC technology by offering a cost-effective, high-performance alternative to traditional noble metal electrodes and contributing to efficient low-grade heat harvesting.

Estimating ocean heat content from the ocean thermal expansion parameters using satellite data

Abstract. Ocean heat content (OHC) is a depth-integrated physical oceanographic variable used to precisely measure ocean warming. Because of the limitations associated with in situ conductivity, temperature, and depth (CTD) data as well as ocean reanalysis system products, satellite-based approaches have gained importance in estimating the daily to decadal variability of OHC over the vast oceanic region. Efforts to minimize the biases in satellite-based OHC estimates are needed to realize the actual response of the ocean to the brunt of climate change. In the current study, an attempt has been made to better implement the satellite-based ocean thermal expansion method to estimate OHC at 17 depth extents ranging from the surface to 700 m. To achieve this objective, artificial neural network (ANN) models were developed to derive thermosteric sea level (TSL) from a given dataset of sea surface temperature, sea surface salinity, geographical coordinates, and climatological TSL. The model-derived TSL data were further used to estimate OHC changes based on the thermal expansion efficiency of heat. Statistical analysis showed high correlation coefficients and low errors in the validation of model-derived TSL and OHC for the 700 m modeling depth (N 388 469, R 0.9926 and 0.9922, RMSE 1.16 m and 1.56 GJ m−2, MBE −0.19 m and −0.24 GJ m−2, MBPE −0.46 % and −0.03 %, MAE 0.76 m and 1.03 GJ m−2, and MAPE 2.34 % and 0.13 %) and nearly similar results at the remaining modeling depths. These results suggest that the proposed ANN models are capable of generating satellite-based daily OHC maps by covering both shallower and deeper oceanic regions of varying bathymetry levels (≥20 m). In addition, the first-ever attempt to estimate the ocean thermal expansion component (i.e., TSL) from satellite data was successful, and the model-derived TSL can be used to obtain high-end sea level rise products in the global ocean.

Performance of heat transfer in Al2O3/MWCNT hybrid nanofluid flow using machine learning models

Abstract This investigation diverges from traditional studies concentrating on single-component nanofluids, instead examining the thermophysical benefits of hybrid nanofluids, like Al₂O₃/MWCNT, aimed at improving thermal conductivity and heat transfer efficiency in passive systems. Machine learning is a promising solution for designing efficient heat exchangers by understanding intricate relationships and utilizing suitable modelling techniques. Numerical simulations were conducted to validate the benchmark results; later, passive techniques were incorporated into the numerical model to predict the heat transfer characteristics. The dataset derived from numerical simulation results is employed to train contemporary machine learning methodologies, including support vector regression (SVR), decision tree (DT), and random forest (RF). Data from experiments and CFD analysis were gathered for preprocessing and machine learning (ML) analysis. The preprocessing phase involved the application of a standard scaler operation to enhance accuracy levels. The models underwent validation using ten experimental data samples to assess their performance against statistical tool metrics. A higher thermal performance factor (ThPF) is observed with the divergent nozzle insert in the plain tube at 0.028 vol% of MWCNT/Al2O3 (HNF3) at Reynolds number 3093. R2 values of SVR, DT and RF are predicted as 0.95, 0.98 and 0.99, respectively, for the case of HNF3 fluid flowing through the divergent nozzle insert. The investigation broadens its conclusions to include improvements in passive heat transfer, encompassing extended surfaces and geometric alterations, offering practical guidance for developing advanced heat exchanger designs.

Optimization of Mold Heating Structure Parameters Based on Cavity Surface Temperature Uniformity and Thermal Response Rates.

Rapid heating cycle molding technology has recently emerged as a novel injection molding technique, with the uniformity of temperature distribution on the mold cavity surface being a critical factor influencing product quality. A numerical simulation method is employed to investigate the rapid heating process of molds and optimize heating power, with the positions of heating rods as variables. The temperature uniformity coefficient is an indicator used to assess the uniformity of temperature distribution within a system or process, while the thermal response rate plays a crucial role in evaluating the heating efficiency of a heating system. The thermal response rate of the cavity and the temperature uniformity coefficient are set as optimization objectives to define parameter ranges for orthogonal experiments. The findings indicate that the optimal range for the lateral distance L1 is 20-30 mm, for L2 it is 50-70 mm, and for the vertical distance (h) it is 3-8 mm. The response surface multiple regression equation derived from the orthogonal experiment data demonstrates a model prediction error rate of 1.8% and 2.4%. Additionally, by applying particle swarm optimization to the regression equation, the study identifies an optimal scheme that reduces system energy consumption by 12.5%, achieves a thermal response rate of 0.75 k/s, decreases the temperature uniformity coefficient by 44.6%, and lowers the temperature difference by 52.17%. This optimization ensures efficient heating of the mold cavity, reduces energy consumption, and enhances the uniformity of the surface temperature distribution, ultimately improving the surface quality of the products.

Solution of the conjugate heat exchange problem for conical heat exchangers

RELEVANCE The article is devoted to the development of new designs of heat exchangers and evaluating the efficiency of their operation. According to the authors, currently of particular interest are conical heat exchangers of the "pipe-in-pipe" type, so the object of research in this paper is a heat exchanger in the form of a truncated cone based on a spring-twisted channel. The introduction of the proposed heat exchange elements and apparatuses into the industry requires additional research. To assess the effectiveness of the application of the considered TA, it is proposed to evaluate its performance in comparison with conical and cylindrical TA based on a smooth-walled pipe. Due to this, two hypotheses will be tested at once: the use of a conical coil heat exchanger is more efficient than a cylindrical one, and the replacement of a smooth-walled pipe with a spring-twisted channel increases the efficiency of the heat exchanger.OBJECT. The aim of the research is to develop a method for setting and solving the conjugate heat exchange problem for a heat exchanger in the form of a truncated cone with a heat exchange element in the form of a spring-twisted channel, analyze the results obtained and evaluate the efficiency in comparison with conical and cylindrical heat exchangers based on smooth-walled heat exchange elements. METHODS. For the numerical solution of the conjugate heat transfer problem, the FEM implemented by means of Ansys was used Fluent. RESULTS. The main results consist in the fact that the authors developed a model and algorithm for calculating conical coil heat exchangers of the pipe-in-pipe type, implemented in the Ansys program, and determined the thermal and hydrodynamic parameters of coil devices. A comparison of coil heat exchangers was also made: a conical one based on a spring-twisted channel with a conical one and a cylindrical one with a smooth-walled heat exchange element. The calculation results showed that replacing a smooth-walled pipe with a spring-wound channel significantly increases the efficiency of heat exchange equipment. CONCLUSION. The significance of the obtained results lies in the possibility of using modern, more efficient and compact heat exchange equipment for technological needs and in the justification of this choice. Thus, with equal initial data, conical heat exchangers are more efficient than cylindrical ones with a heat exchange element in the form of a smooth tube, since they need a smaller heat exchange surface to achieve the necessary thermal and hydrodynamic parameters. The results of calculations prove the prospects of using a conical TA based on a spring-twisted channel and show the need for further study of the influence of the geometric characteristics of both the coil itself and the heat exchange element on the thermal and hydrodynamic characteristics of the proposed HE.

A Review of the Application and Development of Ultra-thin Silicon Chips

The widespread applications of ultra-thin silicon chips across industries such as healthcare, telecommunications, automotive, artificial intelligence, and energy management underscore their pivotal role in driving technological advancements and societal progress by enhancing efficiency, sustainability, and overall performance in various electronic systems. This paper provides an in-depth review of the application and development of ultra-thin silicon chips in modern electronic technology. Ultra-thin silicon chips, characterized by small size, low power consumption, and efficient heat dissipation, offer significant advantages over traditional chips in various electronic products such as smartphones, tablets, and smart wearable devices. The paper discusses the basic principles, fabrication methods, and advantages of ultra-thin silicon chips, highlighting their potential applications in emerging fields like artificial intelligence and the Internet of Things. Furthermore, the paper explores the evolving trends in ultra-thin silicon chip manufacturing technology, emphasizing advancements in nano-technology applications and intelligent manufacturing practices. The diverse applications of ultra-thin silicon chips across industries such as healthcare, telecommunications, automotive, artificial intelligence, and energy management underscore their pivotal role in driving technological advancements and societal progress

Comparative Investigation of Novel Thermo‐Hydraulic Flow Characteristics and Augmentation of Heat Efficiency in 3D Pipes Based on Parametrical Corrugated Shape Configurations

Comparative Investigation of Novel Thermo‐Hydraulic Flow Characteristics and Augmentation of Heat Efficiency in 3D Pipes Based on Parametrical Corrugated Shape Configurations

Breaking the Trade-Off Between Electrical Conductivity and Mechanical Strength in Bulk Graphite Using Metal-Organic Framework-Derived Precursors.

High-performance bulk graphite (HPBG) that simultaneously integrates superior electrical conductivity and excellent strength is in high demand, yet it remains critical and challenging. Herein a novel approach is introduced utilizing MOF-derived nanoporous metal/carbon composites as precursors to circumvent this traditional trade-off. The resulting bulk graphite, composed of densely packed multilayered graphene sheets functionalized with diverse cobalt forms (nanoparticles, single atoms, and clusters), exhibits unprecedented electrical conductivity in all directions (in-plane: 7311 S cm⁻¹, out-of-plane: 5541 S cm⁻¹) and excellent mechanical strength (flexural: 101.17±5.73MPa, compressive: 151.56±2.53MPa). Co nanoparticles act as autocatalysts and binders, promoting strong interlayer adhesion among highly graphitized graphene layers via spark plasma sintering. The strong nano-interfaces between graphite and Co-create critical bridges between graphene nanosheets, facilitating highly efficient electron migration and enhanced strength and stiffness of the assembled bulk nanocomposites. Leveraging these exceptional properties, practical demonstrations highlight the immense potential of the robust material for applications demanding superior electromagnetic interference shielding and efficient heating. An innovative approach, which effectively decouples electrical conductivity from mechanical properties, paves the way for the creation of HPBGs tailored for diverse application sectors.

Microwave Heating Performances of Eucalyptus Camaldulensis Leaves with Silicon Carbide for Biofuel Upgrading

Article Microwave Heating Performances of Eucalyptus Camaldulensis Leaves with Silicon Carbide for Biofuel Upgrading Faizan Ahmad, Muhammad Kashif, Wenke Zhao and Yaning Zhang * School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China * Correspondence: ynzhang@hit.edu.cn Received: 4 December 2024; Revised: 31 December 2024; Accepted: 2 January 2025; Published: 9 January 2025 Abstract: Microwave heating is an efficient and effective heating method for upgrading biofuels. This study investigated the heating performance of eucalyptus camaldulensis leaves with and without silicon carbide (SiC) in a microwave chamber. The effects of quartz reactor volume (50, 100, 150, 200, and 250 mL), microwave power (400, 450, 500, 550, and 600 W), and SiC amount (0, 2.5, 5, 7.5, and 10 g) on the heating performance were analyzed. The result showed that as the quartz reactor volume increased from 50 to 250 mL, the average heating rate of eucalyptus leaves without SiC decreased from 153.2 to 47.2 °C/min, while with SiC, it decreased from 366.8 to 106.2 °C/min. As the microwave power increased from 400 to 600 W, the average heating rate of eucalyptus leaves without SiC increased from 73.3 to 197.4 °C/min, and with SiC, it increased from 138.6 to 352.4 °C/min. When SiC amount increased from 0 to 10 g, the average heating rate of eucalyptus leaves increased from 73.9 to 352.4 °C/min. Relationships were proposed to describe the microwave heating performances of eucalyptus camaldulensis leaves with R2 of 0.9953–0.9999.