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Significant increases in photocatalytic degradation performance have been partially attributed to the contributions of AC, r-GO, MnO2, and their composite species. Activated carbon, r-GO, and MnO2 are dispersed and in good touch with one another. The current study describes the hydrothermal synthesis of nanorod-shaped MnO2 nanostructures and MnO2/AC, MnO2/r-GO, and MnO2/AC/r-GO (MAG NCs) NCs. Various analytical methods were used to examine the structural, bonding, morphological, and photocatalytic aspects of the material. Morphological characterizations (SEM, FE-SEM, and TEM) demonstrated that activated carbon and r-GO coated the MnO2 nanorods. The MAG surface area was studied using BET analysis. Remarkably, MAG NCs have a surface area of 68.8 m2g−1. According to the UV–Vis DRS findings, the optical absorption of MAG NCs was blue-shifted into the visible range. Furthermore, photocatalytic elimination of MO dye in aqueous solution employing the resultant catalysts reaches a maximum degradation efficiency of 97.36% under visible light irradiation for 60 min as compared to MnO2/AC (83.11%), MnO2/r-GO (81.81%), and MnO2 (64.17%). The blue-shifted band gap was attributable to the increase in photocatalytic degradation efficiency of MAG NCs (2.148 eV). Furthermore, the MAG ternary NCs had remarkable chemical stability and had a wide range of applications in photocatalytic dye degradation and wastewater treatment. [ABSTRACT FROM AUTHOR]

Multifunctional building materials with self-sensing capability have great potential for civil engineering applications. The self-sensing capability of typically calcium aluminosilicate matrices of cementitious or geopolymer materials is adopted by admixing electrically conductive admixtures in an amount that ensures optimal electrical properties and their proportionality to mechanical loading. The paper aims to evaluate the self-sensing capability of 4 metashale geopolymer mortars with graphite powder (GP) and carbon fibers (CF) in different ratios, including MGF 5/0, MGF 4.5/0.5, MGF 4/1, and MGF 3/0. The 4-probe measurements at 21 V DC input voltage on (100 × 100 × 100) mm3 samples with embedded copper-grid electrodes evaluate the gauge factor, which corresponds to the monitored changes in electrical resistivity. Despite the limitations of DC measurements, the self-sensing capability is observed for all the mixtures. The most promising response to dynamic loading with an FCR of 0.018%, is observed for the MGF 4.5/0.5 sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gallium coated graphite hybrid particles were prepared. • The hybrid particles have excellent microwave absorption performance. • The formation of gallium oxide shell is very important to microwave absorption. • Heterogeneous interfaces are constructed in the hybrid particles. • Dipole and interfacial polarization is enhanced by these heterogeneous interfaces. Carbon based materials are widely used in the preparation of microwave absorption materials due to their low density, high attenuation loss and large specific surface area. However, their high conductivity usually leads to high reflection loss. In this study, multi-layer heterogeneous interfaces were constructed in liquid metal graphite hybrid powder to reduce reflection loss and enhance microwave absorption performance. Gallium oxide (Ga 2 O 3) layer was formed in Ga coated graphite powder to improve impedance matching and attenuation constant via an annealing treatment. Specifically, the hybrid particles with 50 wt% Ga and being annealed at 120 °C for 2 h have a minimum reflection loss (RL min) value of −42.68 dB and a maximum effective absorption bandwidth (EAB) of 4.11 GHz at a thickness of 3.3 mm. The hybrid particles not only have multi-layer structures with different electrical conductivity, but also form heterojunctions between different interfaces, which can further enhance dipole and interfacial polarization. [ABSTRACT FROM AUTHOR]

The primary goal for the development of energy-storage devices is to find affordable ways to increase their efficiency, activity, and stability. In this regard, transition metal oxide mainly MoO 3 enhances the electrochemical properties of the material due to various oxidation states. On the other hand, carbonaceous materials, such as reduced graphene oxide, provide a large surface area that increases the conductivity of nanomaterials. In this work, we have synthesized pristine and codoped MoO 3 material using the co-precipitation route. While the r-GO based composite was prepared by a simple sonication approach. The prepared composite material showed a higher specific capacitance of 987 F/g than the pristine and codoped material. The BAMO@r-GO discharges after 346 s which was the higher time of discharge than that of pure and codoped material. Moreover, the obtained results from EIS measurement confirmed that the composite material showed less resistance than all other synthesized materials. The synergistic effect between the r-GO and BAMO materials is the reason for the higher supercapacitor performances of BAMO@r-GO. Based on these results, the fabricated BAMO@r-GO material can be effectively utilized as an electrode material in electrochemically powered energy storage devices. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering 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 objective of this study is to improve the thermal characteristics of gypsum ceiling boards intended for building envelope applications, focusing on enhancing energy efficiency by integrating graphite-infused phase change material (PCM). The investigation examines PCM incorporation with graphite powder (PCMGP) at 10 % and 20 % mass ratios using differential scanning calorimetry (DSC) analysis. The results indicate that the melting points of PCM, PCMGP – 10 %, and PCMGP – 20 % are approximately 59.6 °C, 59.6 °C, and 59.8 °C, respectively. Notably, the PCMGP-10 % composite displays a narrower melting temperature range, signifying superior thermal characteristics. The PCMGP-10 % composite layer significantly reduces the average room temperature by up to 3.79 % compared to non-PCM gypsum ceiling boards, up to 2.11 % compared to PCM layers without infused graphite, and up to 1.41 % compared to the PCMGP-20 % composite layer under controlled temperature conditions when applied to gypsum ceiling boards. The optimized PCMGP composite enhances thermal performance and thermal energy storage efficiency, leading to significant electrical energy savings by reducing cooling requirements within the building envelope. The implications of this study are crucial for sustainable construction materials and energy conservation strategies. Incorporating PCMGP composites in building envelopes has the potential to enhance energy efficiency and thermal comfort, thus supporting sustainable and energy-efficient construction practices.

Metal Matrix Composites (MMCs) and Hybrid Metal Matrix Composites (HMMCs) are advanced materials that possess distinctive mechanical properties, rendering them well-suited for a wide range of industrial applications. Nevertheless, the mechanical properties of MMCs and HMMCs can be further improved by optimizing their compositions and production routes. MMCs and HMMCs possess distinct mechanical characteristics, however their processing and production present various obstacles. However, the current processing and manufacturing methods for MMCs and HMMCs have limitations such as high production costs, limited design flexibility, and reduced mechanical properties. Therefore, the problem that needs to be addressed is the development of efficient and cost-effective processing and manufacturing methods that can improve the mechanical properties of MMCs and HMMCs while maintaining their unique properties. Therefore, this study conducted an experimental study on the mechanical and tribological features of HMMCs, where graphite powder and Boron Carbide were used as reinforcements, and AA7075 was used as the matrix. Induction stir casting was used to prepare the composite samples with different wt. % of reinforcements. Here, the Yield Strength (YS), Ultimate Tensile Strength (UTS), elongation, hardness, impact, and wear rate are used as output response characteristics. From the obtained results, YS, UTS, and elongation were enhanced by +85.31%, +88.24%, and -63.75%, respectively, while the hardness and impact strength was improved by approximately 18% and 110%, respectively, with the reinforcement of Gr/B4C as compared to unreinforced AA7075. Finally, the findings of this study could potentially aid in advancement of novel and enhanced hybrid composites for diverse applications.

Metal-matrix composites (MMCs) and hybrid metal-matrix composites (HMMCs) are novel materials that possess distinctive mechanical characteristics, making them well-suited for industrial applications. This research implements an experimental study of the mechanical properties of HMMCs, where weight percentages (2, 3, and 4 wt. %) of zirconium dioxide (ZrO2) and graphite powder (Gr) are used as reinforcements and the aluminum alloy 7475 (AA7475) is used as a matrix. In this investigation, the stir casting method was used to prepare the composite by using AA7475 alloy with pre-heated reinforced particles of ZrO2 and graphite with various reinforcement weight percentages. Among these combinations, AA with 4 wt. % ZrO2 and 2 wt.% Gr showed enhanced mechanical properties. The mechanical properties of the ultimate tensile strength, yield strength, and hardness were evaluated. A Scanning Electron Microscope analysis was conducted to study the reinforcement distribution in the matrix. The input parameters for wire-cut electrical discharge machining (WCEDM) are pulse-on time (TON), pulse peak current (IP), and flushing pressure (PF). The material removal rate and surface roughness are the output responses. Determining the ideal set of process parameters in WCEDM for HMMC also involved the use of the Taguchi design technique known as the L9 orthogonal array. The peak current for the MRR and flushing pressure for the SR are the most prominent parameters.

Micro electrical discharge drilling (ED-drilling) is a machining method used to make micro holes in hard-to-cut materials. The RC-discharge generator is often used because it creates a short and strong discharge spark. However, this method has issues such as current oscillation between tool electrode and workpiece, causing polarity changes that increase tool wear, and a low material removal rate due to long spark delay time. Furthermore, micro ED-drilling results in a large taper angle due to second discharge sparks created by debris in the narrow gap. To address these issues, the effect of adding graphite powder to the working fluid was studied. The graphite powder in kerosene created a bridge effect that reduced tool wear and taper angle, while improving MRR and surface roughness. The electrical conditions were not changed, and the machining process was improved by only altering the working fluid without modifying the existing system. [ABSTRACT FROM AUTHOR]

It is difficult to plug the fracture water channeling of a fractured low-permeability reservoir during water flooding by using the conventional acrylamide polymer gel due to its weak mechanical properties. For this problem, micron graphite powder is added to enhance the comprehensive properties of the acrylamide polymer gel, which can improve the plugging effect of fracture water channeling. The chemical principle of this process is that the hydroxyl and carboxyl groups of the layered micron graphite powder can undergo physicochemical interactions with the amide groups of the polyacrylamide molecule chain. As a rigid structure, the graphite powder can support the flexible skeleton of the original polyacrylamide molecule chain. Through the synergy of the rigid and flexible structures, the viscoelasticity, thermal stability, tensile performance, and plugging ability of the new-type gel can be significantly enhanced. Compared with a single acrylamide gel, after adding 3000 mg/L of micrometer-sized graphite powder, the elastic modulus, the viscous modulus, the phase transition temperature, the breakthrough pressure gradient, the elongation at break, and the tensile stress of the acrylamide gel are all greatly improved. After adding the graphite powder to the polyacrylamide gel, the fracture water channeling can be effectively plugged. The characteristics of the networked water flow channel are obvious during the injected water break through the gel in the fracture. The breakthrough pressure of water flooding is high. The experimental results are an attempt to develop a new gel material for the water plugging of a fractured low-permeability reservoir. [ABSTRACT FROM AUTHOR]

This study experimentally investigates the usability of asphalt concrete pavement containing five different ratios of graphite powder (0%, 1.25%, 2.5%, 3.75% and 5% by weight of the aggregate blend or 0%, 25%, 50%, 75% and 100% of the filler content) as a filler to be potentially used as part of wireless electric roads (ER). As part of the study, first, optimum asphalt binder content for the asphalt mixes without graphite powder was determined as 5%. Then, using the determined optimum asphalt binder content, asphalt mixes containing five different ratios of graphite powder as a filler were prepared and their mechanical and volumetric properties based on Marshall mix design methodology were evaluated. As graphite powder ratios in the asphalt mixes increased, their Marshall stability, flow, voids filled with asphalt and unit weight test results mostly decreased but their air content and voids in mineral aggregate test results increased. Possible reasons for this could be: (1) lower bulk specific gravity of graphite powder, (2) higher asphalt absorbance, (3) having greater surface area compared to that of limestone filler, and (4) weak bonds between sheet-like graphite layers. Furthermore, another batch of asphalt mixes containing five different ratios of graphite powder were prepared and tested in the frequency range of 3–18 GHz for their electromagnetic permittivity properties. It was observed in this study that, except for the specimens with 100% graphite powder ratios, transmission magnitudes of all specimens were above 50% up to 8 GHz, indicating that they had comparably high transmission magnitudes so as comparably low tangent loss values. In the frequency range of 3–13 GHz, transmission magnitudes of the specimens with 25% and 50% graphite powder ratios were consistently higher than that having no graphite powder, the ones with 25% powder ratios had the highest transmission magnitudes in most of the cases in this frequency range. Considering the mechanical, volumetric and electromagnetic property test results of the asphalt mixes with five different ratios of graphite powder, it can be concluded that the use of 25% graphite powder ratio (corresponding to 1.25% of the aggregate blend used in the mixes), has a comparably lower negative effect on mechanical and volumetric properties of asphalt mixes and has a positive effect on electromagnetic permittivity properties of asphalt mixes. Asphalt mixes produced with this graphite powder ratio can be considered to be used as part of wireless ER.

Metal-matrix composites (MMCs) and hybrid metal-matrix composites (HMMCs) are novel materials that possess distinctive mechanical characteristics, making them well-suited for industrial applications. This research implements an experimental study of the mechanical properties of HMMCs, where weight percentages (2, 3, and 4 wt. %) of zirconium dioxide (ZrO2) and graphite powder (Gr) are used as reinforcements and the aluminum alloy 7475 (AA7475) is used as a matrix. In this investigation, the stir casting method was used to prepare the composite by using AA7475 alloy with pre-heated reinforced particles of ZrO2 and graphite with various reinforcement weight percentages. Among these combinations, AA with 4 wt. % ZrO2 and 2 wt.% Gr showed enhanced mechanical properties. The mechanical properties of the ultimate tensile strength, yield strength, and hardness were evaluated. A Scanning Electron Microscope analysis was conducted to study the reinforcement distribution in the matrix. The input parameters for wire-cut electrical discharge machining (WCEDM) are pulse-on time (TON), pulse peak current (IP), and flushing pressure (PF). The material removal rate and surface roughness are the output responses. Determining the ideal set of process parameters in WCEDM for HMMC also involved the use of the Taguchi design technique known as the L9 orthogonal array. The peak current for the MRR and flushing pressure for the SR are the most prominent parameters. [ABSTRACT FROM AUTHOR]

Metal Matrix Composites (MMCs) and Hybrid Metal Matrix Composites (HMMCs) are advanced materials that possess distinctive mechanical properties, rendering them well-suited for a wide range of industrial applications. Nevertheless, the mechanical properties of MMCs and HMMCs can be further improved by optimizing their compositions and production routes. MMCs and HMMCs possess distinct mechanical characteristics, however their processing and production present various obstacles. However, the current processing and manufacturing methods for MMCs and HMMCs have limitations such as high production costs, limited design flexibility, and reduced mechanical properties. Therefore, the problem that needs to be addressed is the development of efficient and cost-effective processing and manufacturing methods that can improve the mechanical properties of MMCs and HMMCs while maintaining their unique properties. Therefore, this study conducted an experimental study on the mechanical and tribological features of HMMCs, where graphite powder and Boron Carbide were used as reinforcements, and AA7075 was used as the matrix. Induction stir casting was used to prepare the composite samples with different wt.% of reinforcements. Here, the Yield Strength (YS), Ultimate Tensile Strength (UTS), elongation, hardness, impact, and wear rate are used as output response characteristics. From the obtained results, YS, UTS, and elongation were enhanced by +85.31%, +88.24%, and -63.75%, respectively, while the hardness and impact strength was improved by approximately 18% and 110%, respectively, with the reinforcement of Gr/B4C as compared to unreinforced AA7075. Finally, the findings of this study could potentially aid in advancement of novel and enhanced hybrid composites for diverse applications. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society 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.)

This research focuses on the thermal properties of three distinctive paraffin waxes—PCMA, PCMB, and PCMC—each characterized by a specific melting point. The crucial phase transition temperature intervals and latent heat values were examined using differential scanning calorimetry (DSC) in the temperature range of 0 °C to 80 °C. These parameters are pivotal for the effective application of these phase change materials (PCMs) in building envelopes, influencing the overall heat storage performance. The study delved into the development and encapsulation of blends containing both the phase change material (PCM) and graphite. This involves combining the chosen PCM with graphite powder and examining the weight ratios of 10% and 20%. The thermal characteristics of these blends revealed that a 10% ratio of graphite powder proved effective in improving the PCM with graphite. This resulted in a reduced range of melting and solidification temperatures while maintaining the essential chemical structure of the PCM without additives. Furthermore, the practical application of PCM–graphite composites within a building's envelope was explored, revealing a substantial reduction in heat transfer from the exterior to the interior of the building. This underscores the potential for energy-efficient building designs. [ABSTRACT FROM AUTHOR]

The enhancement of the mechanical properties of TiAl alloys through the introduction of a second-phase reinforcement is highly essential. In this paper, using graphite powder as a carbon source, the Ti2AlC phase is introduced to improve the compression and friction properties of the TiAl alloy. Concurrently, the effects of graphite powder additions on the microstructure and room-temperature mechanical properties of Ti-45Al-8Nb-xC (mass%) alloys are investigated. The results show that as the volume fraction of Ti2AlC and the interdendritic γ phase increases, the length–diameter ratio of the Ti2AlC phase decreases with increases in the graphite powder addition. The addition of graphite powder results in a refining effect on the grain size and lamellar spacing of the Ti-45Al-8Nb-xC (mass%) alloys. As the graphite powder content increases from 0 to 0.9 mass%, the microhardness increases from 557 HV to 647 HV. The room-temperature compressive strength and strain of the Ti-45Al-8Nb-xC (mass%) alloys first increase and then decrease with the addition of graphite powder. Specifically, when the content of graphite powder is 0.6 mass%, the alloy exhibits a maximum compressive strength and strain of 1652 MPa and 22.2%, respectively. Compared with the alloy without the graphite powder addition, the compressive strength and strain are improved by 37.7% and 62.1%, respectively. The wear resistance of the alloys is improved through the addition of graphite powder and the wear rate decreases from 5.062 to 2.125 × 10−4 mm3·N−1·m−1 as the content of graphite powder increases from 0 to 0.9 mass%. [ABSTRACT FROM AUTHOR]

The rapid use of additive manufacturing (AM) in electronic industry identifies the need of flexible electrically conductive materials suitable for 3D printing. Challenges like buckling of flexible filament and complexity in addition of conductive fillers makes pellet‐based extrusion the most suitable alternative for part printing. In the present work, graphite powder is combined with ethylene vinyl acetate (EVA) to print flexible electrically conductive parts. EVA graphite composite with filler loading up to 30% has been investigated for its electrical conductivity and part printability. The composite made was found electrically conductive and suitable for part printing. The parts were printed on a CNC milling machine by using a retrofitted material extrusion tool with nozzle of 0.4 mm diameter and temperature range of 130–140°C. Parts were printed on a detchable heating bed placed on the milling machine setup. Samples of EVA with graphite filler by weight of 5%, 10%, 20%, and 30% were printed and were checked for electrical conductivity. When the filler content was increased from 10% to 20%, the electrical resistance of the composite was reduced by 62.6%. The presence and uniform dispersion of graphite flakes in the polymer matrix of EVA were guaranteed by the rheological and morphological characterization of the composite. Applications of 3D printable flexible electrically conductive parts lies in numerous domains including biosensors, wearable health monitoring devices, capacitors, field effective transistors, light emitting diodes, solar cells, and electronic displays. Highlights: CNC milling machine‐assisted 3D printing is used for part printing.Graphite powder is combined with EVA pellets.Pellet‐based extrusion is used to print flexible parts.3D printability of parts with resistivity 32.64 Ω‐cm was achieved. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) provide a good resolution for the latent heat storage system which can be used in many application fields such as solar energy utilization and waste heat recovery. This study aims to experimentally investigate the impact of graphite powder on the thermal characteristics and heat transfer performance of paraffin with ceresin (PC) as a PCM, using water as the heat transfer fluid. Experimental tests were conducted to analyze the heat transfer performance of PC and the influence of graphite powder on its thermal characteristics. Different masses of graphite powder were employed to assess their effects on the heating rate and the time required for PC to reach its melting temperature. The experimental results revealed that the addition of graphite powder improved the heating rate of both PC and water, attributed to its high thermal conductivity. Furthermore, the time for PC to reach the melting temperature was decreased with varying amounts of graphite powder, achieving a maximum reduction of 17.2% with the addition of 40 g of graphite powder. However, the effectiveness of graphite powder in enhancing heat transfer efficiency was found to be limited, with the optimal promotion effect observed at around 40 g of graphite powder for 500 g of PC. The findings of this investigation provide valuable insights for the design of phase change energy storage systems, with potential applications including heat pump drying units, greenhouse energy storage in modern agriculture, and solar energy storage utilization technology. The theoretical basis established can contribute to the development and optimization of PCM-based systems in diverse practical scenarios.

To further improve the efficiency of electrical discharge machining of advanced materials, the possible technological improvement of the process is achieved by adding graphite powder to the dielectric. In this study, the Taguchi approach was applied to determine the effects of input parameters such as discharge current, pulse duration, duty cycle, and graphite powder concentration on surface roughness in machining titanium alloys. L9 orthogonal array, signal-to-noise ratio (S/N), and ANOVA were used to design and analyze the experiment. Discharge current was determined to be the factor that had the strongest influence on surface roughness. Based on ANOVA, pulse duration was the second influential parameter, followed by graphite powder and duty cycle. In addition, an optimum condition was found to improve surface roughness. A discharge current of 1.5 A, a pulse duration of 32 µs, a duty cycle of 30% and a powder concentration of 12 g/l resulted in minimum surface roughness. [ABSTRACT FROM AUTHOR]

This study experimentally investigates the usability of asphalt concrete pavement containing five different ratios of graphite powder (0%, 1.25%, 2.5%, 3.75% and 5% by weight of the aggregate blend or 0%, 25%, 50%, 75% and 100% of the filler content) as a filler to be potentially used as part of wireless electric roads (ER). As part of the study, first, optimum asphalt binder content for the asphalt mixes without graphite powder was determined as 5%. Then, using the determined optimum asphalt binder content, asphalt mixes containing five different ratios of graphite powder as a filler were prepared and their mechanical and volumetric properties based on Marshall mix design methodology were evaluated. As graphite powder ratios in the asphalt mixes increased, their Marshall stability, flow, voids filled with asphalt and unit weight test results mostly decreased but their air content and voids in mineral aggregate test results increased. Possible reasons for this could be: (1) lower bulk specific gravity of graphite powder, (2) higher asphalt absorbance, (3) having greater surface area compared to that of limestone filler, and (4) weak bonds between sheet-like graphite layers. Furthermore, another batch of asphalt mixes containing five different ratios of graphite powder were prepared and tested in the frequency range of 3-18 GHz for their electromagnetic permittivity properties. It was observed in this study that, except for the specimens with 100% graphite powder ratios, transmission magnitudes of all specimens were above 50% up to 8 GHz, indicating that they had comparably high transmission magnitudes so as comparably low tangent loss values. In the frequency range of 3-13 GHz, transmission magnitudes of the specimens with 25% and 50% graphite powder ratios were consistently higher than that having no graphite powder, the ones with 25% powder ratios had the highest transmission magnitudes in most of the cases in this frequency range. Considering the mechanical, volumetric and electromagnetic property test results of the asphalt mixes with five different ratios of graphite powder, it can be concluded that the use of 25% graphite powder ratio (corresponding to 1.25% of the aggregate blend used in the mixes), has a comparably lower negative effect on mechanical and volumetric properties of asphalt mixes and has a positive effect on electromagnetic permittivity properties of asphalt mixes. Asphalt mixes produced with this graphite powder ratio can be considered to be used as part of wireless ER. [ABSTRACT FROM AUTHOR]

The effect of graphite powder on the machining characteristics in graphite-powder-mixed electrochemical discharge machining of microholes was still not clear. How the discharge mechanism changed with the addition of graphite powder into the electrolyte, which further led to changes in the morphology of the machined holes, remained to be revealed. In this study, a series of microhole machining experiments were conducted in glass. Comparisons of the discharge energy, microhole entrance diameter, hole taper, and tool electrode morphology after machining were made when machining in the electrolytes with and without graphite powder. Experimental results revealed that there were a lot of small pulse currents distributed on the current waveform when machining with the graphite-powder-mixed electrolyte. The average discharge energy of the small pulse current was 2.8 times as much as that of the general electrochemical discharge. After introducing graphite powder into the electrolyte, the entrance diameter of the hole became larger when the hole depth was deeper than 200 μm. The HAZ width increased with increasing hole depth at the voltage of 37–41 V, while it decreased at the voltage of 43 V. A reduction in hole taper angle with a range of 0.5° to 2.3° was achieved. In addition, after machining in electrolytes with and without graphite powder, the tool electrode surfaces showed different morphologies due to different discharges. [ABSTRACT FROM AUTHOR]

This study deals with fuzzy logic based modeling and parametric analysis in powder mixed electrical discharge machining of titanium alloys. The central composition plan was used to design the experiments considering four parameters, namely discharge current, pulse duration, duty cycle as well as graphite powder concentration. All experiments were performed with different parameter combinations and the performance, i.e., surface roughness, was evaluated. The adaptive neuro-fuzzy inference system was used to understand and define the inputoutput relationship. The experimental results and the model results were compared and it was found that the results accurately predicted the reactions in the erosion of titanium alloys. In addition, the model was verified using data that had not participated in the training of the model, with an error of about 10 %. In addition, a fuzzy plot was used to analyze the influence of input parameters on surface roughness. It was found that the discharge current was the most important influencing parameter. Additional experiments proved the positive effect of graphite powder, which reduced the surface roughness by 27 %. [ABSTRACT FROM AUTHOR]

It is difficult to plug the fracture water channeling of a fractured low-permeability reservoir during water flooding by using the conventional acrylamide polymer gel due to its weak mechanical properties. For this problem, micron graphite powder is added to enhance the comprehensive properties of the acrylamide polymer gel, which can improve the plugging effect of fracture water channeling. The chemical principle of this process is that the hydroxyl and carboxyl groups of the layered micron graphite powder can undergo physicochemical interactions with the amide groups of the polyacrylamide molecule chain. As a rigid structure, the graphite powder can support the flexible skeleton of the original polyacrylamide molecule chain. Through the synergy of the rigid and flexible structures, the viscoelasticity, thermal stability, tensile performance, and plugging ability of the new-type gel can be significantly enhanced. Compared with a single acrylamide gel, after adding 3000 mg/L of micrometer-sized graphite powder, the elastic modulus, the viscous modulus, the phase transition temperature, the breakthrough pressure gradient, the elongation at break, and the tensile stress of the acrylamide gel are all greatly improved. After adding the graphite powder to the polyacrylamide gel, the fracture water channeling can be effectively plugged. The characteristics of the networked water flow channel are obvious during the injected water break through the gel in the fracture. The breakthrough pressure of water flooding is high. The experimental results are an attempt to develop a new gel material for the water plugging of a fractured low-permeability reservoir.

The effects of two kinds of graphite powders with different particle sizes and their contents on the fluidity, setting time, mechanical strength and thermal conductivity of phosphogypsum based self-leveling mortar were studied. The results show that the fluidity of mortar decreases, the setting time shortens, the strength decreases, and the thermal conductivity increases linearly with the increase of the mass fraction of cementitious material replaced by graphite powder. At the same dosage, the fluidity and mechanical strength loss of mortar mixed with 1200 mesh graphite powder are smaller, while the setting time of mortar with 325 mesh graphite powder is shortened more slowly and the thermal conductivity rises faster; The hydrophobic and agglomeration effects of graphite powder will reduce the fluidity of mortar, while its surface nucleation and micro aggregate effect will shorten the setting time of mortar and can make up part of the strength loss. Besides, the addition of graphite powder with high thermal conductivity will reduce the internal thermal resistance, form thermal conduction channels, and improve the thermal conductivity of self-leveling mortar. The optimized phosphogypsum based self-leveling mortar mixed with 6% 1200 mesh graphite powder meets the requirements of the standard JC/T1023-2021 "Gypsum based self-leveling motor", and its thermal conductivity is increased by 37.1%. [ABSTRACT FROM AUTHOR]

This research focuses on the thermal properties of three distinctive paraffin waxes—PCMA, PCMB, and PCMC—each characterized by a specific melting point. The crucial phase transition temperature intervals and latent heat values were examined using differential scanning calorimetry (DSC) in the temperature range of 0 °C to 80 °C. These parameters are pivotal for the effective application of these phase change materials (PCMs) in building envelopes, influencing the overall heat storage performance. The study delved into the development and encapsulation of blends containing both the phase change material (PCM) and graphite. This involves combining the chosen PCM with graphite powder and examining the weight ratios of 10% and 20%. The thermal characteristics of these blends revealed that a 10% ratio of graphite powder proved effective in improving the PCM with graphite. This resulted in a reduced range of melting and solidification temperatures while maintaining the essential chemical structure of the PCM without additives. Furthermore, the practical application of PCM–graphite composites within a building’s envelope was explored, revealing a substantial reduction in heat transfer from the exterior to the interior of the building. This underscores the potential for energy-efficient building designs.

The incessant nature of electrical power supplies in a developing country like Nigeria, the dependence on dry cell batteries for varying domestic applications such as transistor radios, torchlights, remote controls, amongst others continues to rise unabated. Improper disposal of these batteries poses serious adverse effect on the environment and human health. In this study, over 1000 dry cell batteries were collected from different locations in Ede, Osun State sorted and sectioned to harvest the carbon rods which is a key component of the battery cell. The rods were pulverized for about 15 hours and screened into different particle sizes using standard sieves. The microstructural characterization was investigated using Scanning Electron Microscopy (SEM), Energy Displacer Spectroscopy (EDS), X-ray Diffractometer (XRD), and Ultraviolet (UV) Spectroscopy. High yield graphite powders (98%) were obtained from the processing. Absorption peak was observed at 272.5 nm by UV spectroscopy while XRD plots yielded a narrow peak of 26.60. The characterization results show good agreement with those available in literature.

The early-age hydration characteristics of composite binder containing graphite powder (GP) with two different finenesses were investigated by determining the hydration heat, thermo gravimetric, morphology of hardened paste as well as the compressive strength of mortar. The experimental results show that: replacing 2%–6% of cement with graphite powder significantly improves the piezoresistive effect of early age mortar, can be used to monitor accidental loads caused by dropped objects, collisions, or other accident events, and thus avoids initial damage. Some GP provides additional nucleation sites that lead to a fast formation of hydration products (nucleation-site effect). However, due to the almost hydrophobic water contact angle, most of the GP causes a large number of micro-cracks in the hydrated paste (gap effect). Because of the lamellar shape and high surface energy, GP is easily balled and can not be uniformly distributed in the composite, resulting in clumping together and wrapping some of the cement particles (barrier effect). Due to nucleation-site effect, when the dosages of coarse and fine GP reached 2% and 4%, 1 d strength were increased by 9.1% and 9.6%, respectively. At 3 days, as the interior damage caused by the gap effect gradually increased, and the retarding effect on cement hydration caused by barrier effect was enhanced. GP has an obvious negative effect on compressive strength. However, micro-cracks caused by fine GP are less, so its negative effect on 3 d compressive strength is lower. [ABSTRACT FROM AUTHOR]

The effect of graphite powder on the machining characteristics in graphite-powder-mixed electrochemical discharge machining of microholes was still not clear. How the discharge mechanism changed with the addition of graphite powder into the electrolyte, which further led to changes in the morphology of the machined holes, remained to be revealed. In this study, a series of microhole machining experiments were conducted in glass. Comparisons of the discharge energy, microhole entrance diameter, hole taper, and tool electrode morphology after machining were made when machining in the electrolytes with and without graphite powder. Experimental results revealed that there were a lot of small pulse currents distributed on the current waveform when machining with the graphite-powder-mixed electrolyte. The average discharge energy of the small pulse current was 2.8 times as much as that of the general electrochemical discharge. After introducing graphite powder into the electrolyte, the entrance diameter of the hole became larger when the hole depth was deeper than 200 μm. The HAZ width increased with increasing hole depth at the voltage of 37–41 V, while it decreased at the voltage of 43 V. A reduction in hole taper angle with a range of 0.5° to 2.3° was achieved. In addition, after machining in electrolytes with and without graphite powder, the tool electrode surfaces showed different morphologies due to different discharges.

The irreversible lithium loss due to the formation of solid electrolyte interphase (SEI) in the initial cycle on the graphite anode greatly reduces the overall cell energy density of lithium ion batteries, that is, the lost Li ions from forming SEI lead to the decrease of Li ions for the intercalation. The method of cathode prelithiation has been widely explored to compensate this lithium loss. However, these cathode additives with high lithium contents inevitably lower the loading of the cathode active materials. Here we report a novel approach to solve this challenge, a facile graphite prelithiation method by preforming SEI layers on the surface of graphite powders (Pre-SEI graphite) utilizing a specially designed flow cell. The Li accommodation in the graphite anode can be controlled by the operating time and current density in the flow cell for the electrochemical SEI formation. As a result, we demonstrate a 10% initial Columbic efficiency increase of the LiFePO 4 electrode in a full cell configuration using the Pre-SEI graphite, compared with the pristine graphite anode. The electrochemical preformation of SEI on the graphite powders offers a complete solution to offset initial lithium loss without a sacrifice of active cathode material loading. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymer Matrix Composites (PMCs) are composed of a variety of continuous or short fibres with organic based polymer matrices. In PMCs, the reinforcement gives stiffness and high strength. The role of matrix material is to tie the fibres together and to transfer load between them. In this research epoxy (LY 556), with hardener (HY 0951) are reinforced with the Pine Apple Leaf Fibre (PALF), graphite powder and Silicon Carbide (SiC) using traditional hand lay-up technique. The attempt is made to evaluate the influence of SiC and PALF on the tribological behaviour. Results show that SiC particulate hybrid composites show higher wear resistance compared to all tested composites. PALF and graphite reinforcement provides a cushioning effect and solid lubrication to the composites that lead to higher wear resistance. [ABSTRACT FROM AUTHOR]

With the continuous progress of artificial intelligence and other manufacturing technologies, there is promising potential for wearable piezoresistive sensors in human physiological signal detection and bionic robots. Here, we present a facile solution-mixing process to fabricate a multiwalled carbon nanotube/graphite powder (MWCNT@Gp) film, which has high sensitivity and great linearity and is more oriented to flexible piezoresistive sensors. The sensor consists of two parts: a spinosum microstructure shaped by a sandpaper template and polydimethylsiloxane (PDMS) as the top substrate and interdigital electrodes as the bottom substrate. The experiments we have conducted show that these two parts provide good protection to the MWCNTs@Gp film and improve sensor sensitivity. Additionally, the sensitivity of the optimal ratio of multiwalled carbon nanotubes and graphite powder is analyzed. The 5%MWCNT@5%Gp composites were found to have relatively good conductivity, which is convenient for the fabrication of conductive films of piezoresistive sensors. Finally, we conducted application experiments and found that the flexible piezoresistive sensor can detect minute signals of human motion and different pressure points. This indicates the feasibility of portable sensors in electronic skin and smart devices. [ABSTRACT FROM AUTHOR]

Based on the study of the chemical composition and analysis of the physicochemical properties of waste from a number of metallurgical enterprises in the Zaporizhzhya region, the possibility of using waste as charge materials for the production of magnesium-based alloys has been established. The possibility of using solid salt chlorinator melt (SCM) from ZTMC as a flux in the smelting of magnesium alloy instead of the flux VI-2 has been studied; its effect on the structure and mechanical properties of casting was investigated. The technological possibility of using these chloride wastes in the smelting of the ML5 alloy is shown. It was established that the use of SCM as a flux in the smelting of magnesium alloy contributes to the grinding of the structure and improvement of the mechanical properties of the metal of experimental smelting. The possibility of modification of foundry magnesium alloy with graphite powder (GP), which is the waste from JSC «Ukrgrafit», is investigated. It is shown that the optimal GP additive in the volume of 0.05...0.3 % contributes to the grinding of metal grain and increases its strength characteristics due to additional strengthening of both solid solution and eutectoid. It is established that carbon changes the parameters of eutectic transformation, as a result of which, with an increase in its concentration in the alloy, the volume of eutectoid of type δ+γ (Mg4Al3) decreases markedly. Testing the proposed waste for the smelting of the M5 alloy showed that no changes in melting technology are required while the environmental safety of the devised technological process meets the established standards; their quality was improved while increasing the strength limit by 25 %, and plasticity by 30 %. At the same time, the use of waste in the smelting of magnesium alloys can reduce costs in its production, and improve the environmental situation due to the fact that waste is not disposed of at landfills but reused in metallurgical industries [ABSTRACT FROM AUTHOR]

Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece's surface using electricity with a high energy density. The quality of the electrical discharge-machined surface is related to its surface integrity in which the surface's roughness, residual stresses, micro hardness and surface micro cracks are some of the major factors. In this research, graphite powder was mixed in a dielectric with a particle size of 20 µm, 30 µm, and 40 µm, with the concentration of the graphite powder ranging from 2 g/L to 4 g/L. Moreover, the peak current and pulse time on were also coupled with an additive of graphite powder to investigate the effect on the surface quality, i.e., the recast layer thickness, micro hardness and crater depth as well as the material removal rate (MRR) and tool wear rate (TWR). A Box–Behnken design was employed to design the experiments and the experimental results revealed that the graphite powder size and concentration coupled with the electrical parameters (peak current and pulse time on) significantly influenced the recast layer thickness, micro hardness, crater size, MRR and TWR. The crater depth and micro hardness were maximized at a higher concentration and particle size, while the recast layer thickness was reduced with a higher gain size. [ABSTRACT FROM AUTHOR]

Many aluminum nanocomposites consisting of a single particulate phase have been synthesized and tested in the past. However, vibration damping characteristics of aluminum nanocomposite based on ensemble or combination of two morphologically different carbon-based materials have not been reported. Therefore, in this work the focus is to synthesize an aluminum nanocomposite based on the combination of two different carbon-based particulate phases namely graphite flake and carbon fiber in order to identify any improvement in the damping ability of the as-synthesized aluminum nanocomposite material. Aluminum nanocomposite was prepared using stir casting method. The particulate phases of carbon were used in varying weight compositions but were always in an equal ratio relative to each other. The material was casted in form of thin rectangular bars using metallic dies and tested in a cantilever beam configuration. MEMS based accelerometer via Arduino microcontroller was used to collect the time dependent response at the free end of the beams. The damping constant ζ was estimated from the response curves. Experiments indicate that compared to the pristine aluminum bars, the damping ability of the as-synthesized aluminum nanocomposite increases by almost 117 % at 3 wt% of the particulate phase. The increase in damping is mainly attributed to the trans-granular frictional effects and weak interfacial bonding between the metal matrix and the particulate phases. Aluminum nanocomposite is successfully prepared using combination of two morphologically different carbon-based particulate phases. The as-synthesized material shows favorable damping performance that can be exploited in structural, automotive, marine and aerospace applications. [ABSTRACT FROM AUTHOR]

The search for recycling methods of composite materials indicated the possibility of using composites with polyester-glass recyclate as structural elements. The main aim of the article was to analyse the influence of the graphite percentage content on the mechanical and structural properties of such composites. Composite materials were made by hand laminating with 10% polyester-glass recyclate and graphite nano-additive. Samples for the static tensile test were prepared, which was carried out in accordance with the applicable standard on a universal testing machine. The obtained results showed that with the increase in the amount of graphite, the properties of the composite decrease; however, disproportionately to the % of its content. [ABSTRACT FROM AUTHOR]

The paper describes the development of an electrochemical sensor to be used for the determination of synthetic food colorants such as Sunset Yellow FCF (SY) and Tartrazine (TZ). The sensor is a carbon paper (CP) electrode, manufactured by using hot lamination technology and volume modified with fine-grained graphite powder (GrP). The sensor (GrP/CP) was characterized by scanning electron microscopy, energy dispersive spectrometry, electrochemical impedance analysis, cyclic, linear sweep and differential pulse voltammetry. The mechanism of SY and TZ electrochemical oxidation on GrP/CP was studied. The developed sensor has good electron transfer characteristics and low electron resistance, high sensitivity and selectivity. Applying the differential pulse mode, linear dynamic ranges of 0.005–1.0 μM and 0.02–7.5 μM with limits of detection of 0.78 nM and 8.2 nM for SY and TZ, respectively, were obtained. The sensor was used to detect SY and TZ in non-alcoholic and alcoholic drinks. The results obtained from drink analysis prove good reproducibility (RSD ≤ 0.072) and accuracy (recovery 96–104%). [ABSTRACT FROM AUTHOR]

The present research emphasizes a novel approach for synthesizing graphite powder derived from coconut shell (CS) as a precursor, particularly focusing on investigating the effects of hydrofluoric acid (HF) in removing silica and other impurities. The cost-effective pyrolysis technique employed in synthesizing graphite powder entails heating CS to 900 °C, followed by treatment with HF at varying sample-to-acid ratios. Several characterization methods are used to validate the successful synthesis of graphite powder, such as X-ray Diffraction (XRD), Raman Spectroscopy, Fourier-transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). XRD analysis shows a distinctive graphitic structure, with Gr14 (graphite prepared with a CSCP to HF ratio of 1:4) exhibiting a high graphitization degree of 93.02 %, indicative of excellent crystal structure and high-quality graphite. FTIR analysis of coconut shell charcoal powder (CSCP) reveals the presence of various oxygen-related functional groups, effectively removed by HF washing, leading to graphite with minimal impurities. The Raman spectra of Gr14 demonstrate fewer defects and a more organized structure than other samples. SEM image of CSCP reveals particles with non-uniform morphologies, while the EDX spectra indicate that Gr14 consists of 97.84 % carbon. Treating CSCP with HF enhances the electrical conductivity of the graphite, with Gr14 exhibiting a higher conductivity value. TGA results reveal the improved thermal stability of the graphite. The residual weight of Gr14 is maximum, confirming its exceptional thermal stability and purity. The findings suggest that HF has a significant influence on improving the purity of CS-derived graphite. The study concludes that, among the prepared samples, Gr14 exhibits favorable characteristics, such as minimal impurities, superior crystal structure, higher carbon content, good electrical conductivity, high thermal stability, and fewer defects, comparable to pure graphite. Future research in this study aims to use CS-derived graphite powder for synthesizing nanomaterials like graphene oxide (GO) and reduced graphene oxide (rGO). [Display omitted] • The synthesis of graphite powder involves a pyrolysis approach, with CS heated at 900°C and treated with HF. • HF has a significant influence on improving the purity of CS-derived graphite powder. • The prepared samples indicate well-defined graphitic features with minimal impurities. • Gr14 exhibits favorable characteristics, comparable to pure graphite, and is preferable for synthesizing GO and rGO. [ABSTRACT FROM AUTHOR]

Rubber composites deliver unsatisfactory mechanical performance if the rubber matrices, such as natural rubber, lack appropriate dispersion of fillers such as silica. This study explored the dispersion and reinforcement performance of binary fillers in natural rubber. Graphite powder was used as a solid lubricating silica filler in the rubber matrix, and shear force was applied using a conventional two-roll mixing mill. The curing, mechanical, and morphological properties were studied to evaluate the mechanism of binary filler dispersion in the rubber matrix. Binary fillers comprising silica and graphite offered better mutual dispersion, which was observed by scanning electron microscopy and mechanical testing and confirmed by atomic force microscopy. Better filler dispersion in natural rubber improved the mechanical and age resistance properties. The modulus at 100% strain and stress at break of unfilled rubber were increased by nearly 110% and 15%, respectively, when 20 phr (per hundred gram of rubber) of binary filler in a 1:1 weight ratio was used, and the composite exhibited better aging resistance and mechanical properties, compared to those of composites with single-filler systems, which may be attributable to the excellent filler dispersion in the rubber matrix. [ABSTRACT FROM AUTHOR]

Three types (type-A, B, and C) of composite polymeric membranes (CPMs) based on poly vinyl chloride (PVC) and different fillers (sodium polyacrylate and sodium polyacrylate-graphite) soaked in water and 0.5 N HCl were prepared using solvent casting method. Different physicochemical parameters such as microscopic surface study, water uptake, perpendicular swelling, density, porosity (ε), ion exchange capacity, and conductivity of the as the prepared CPMs were evaluated. Interestingly, type-A CPM cast with filler-A has greater values of the above parameters except density and ionic conductivity than those of type-B and C CPMs. The water uptake of type-A, B and C composite membranes was respectively in the range of 220.42–534.70, 59.64–41.65, and 15.94–2.62%. Ion exchange capacity of type-A, B and C CPMs was in the range of 3.669 × 107–2.156 × 107, 5.948 × 107–1.258 × 107, and 1.454 × 107–1.201 × 107 m.eq.g−1 respectively while the conductivity order was type-A < B < C. These types of CPMs may be helpful in many applications including proton exchange membranes, fuel cell like devices, as sensors for different metals, gas purification, water treatment, and battery separators. [ABSTRACT FROM AUTHOR]

Aluminium Covetic metallurgical synthesis along with the characterization of cast material results were presented in this paper. Aluminium- 3% graphite (carbon) composites were fabricated by applying different voltages and amperages of direct current through the stir-casting process. This process, called Covetic based on patent applications of Third Millennium Metals. Obtained casts were tested for their chemical composition, density, tensile strength, hardness, microstructures, and electrical conductivity measurements using an Oxford PMI-Master Pro spark emission spectrometer, a DA-300M density measurement device, a WDW-200 universal tensile test machine, a HBA-3000S automatic Brinell Hardness Tester, a scanning electron microscope with Energy-Dispersive Spectroscopy and an AT512 Precision Ohmmeter, respectively. Moreover, increasing of amperages and/or decreasing of voltages of direct current ensured considerable increasing of electrical conductivity (≈ 34%), the notable decrement in the density (≈ 0.94%), an enhancement in the tensile strength (≈ 18%) and the hardness (≈ 15%) of aluminium Covetic casts compared to the parent metal. In summary, results show that the increasing of amperages and/or decreasing of voltages of direct current has a superior influence on improving electrical conductivity of aluminium-graphite Covetic casts with better mechanical properties.

• Low-cost AC/SS and GP/SS composite cathodes supports H 2 O 2 and power production. • AC/SS and GP/SS cathodes effectively degrade RR 114 via biofenton reaction. • Degradation of RR 114 achieved 96 and 90% respectively in 6 h reaction time. • pH, catholytes, Fe2+ and RR 114 concentration impact RR 114 degradation. The foremost obstacle in scale up application of Bioelectro-Fenton dye wastewater treatment process is high cost of cathode material. The study proposes a low-cost activated carbon/stainless steel (AC/SS) and Graphite powder/stainless steel (GP/SS) composite cathodes, where SS allocates the current, while AC/GP concurrently supports Hydrogen peroxide (H 2 O 2) production. Composite AC/SS and GP/SS cathode enabled Acid Red 114 (AR 114) oxidative removal by means of bio-electro-Fenton in microbial fuel cell (MFC) is also investigated. Characterized by different microscopic, spectroscopic, and electrochemical techniques, it is observed that the composite AC/SS and GP/SS cathodes may well be fabricated and involve in H 2 O 2 and power generation of 1420 µM /2680 µM and 4000 mWm−3/4050 mWm−3 respectively. The results also disclose that the MFC system efficiency is crucially associated to operating conditions involving initial AR 114 concentration (20 mg/L), catholyte pH (3), different catholytes, their concentration (75 mM), and Fe2+ dosage (0.5 mM). All investigated conditions are observed to impact the degradation efficiency and apparent first order rate constant for AR 114. The corresponding rate constants and efficiency for the degradation for both cathodes are 0.13 h−1/ 0.08 h−1 and 96%/90%, respectively. The outcomes validate these fabricated cathodes as sustainable substitute of expensive and complex material. [ABSTRACT FROM AUTHOR]