Search

The usage of jute/cotton natural composites has surged in almost all fields of engineering due to their advantage of possessing high strength to weight ratio and biodegradability. This paper deals with the fabrication and investigation of mechanical properties of jute/cotton fiber reinforced epoxy composite which is relatively a hybrid composite. In this study, the composite is fabricated by a hand layup process followed by compression molding method with varying the number of layers of composite laminates also with different cutting angles. The composites are prepared with four different proportions of jute/cotton fibers. Various mechanical tests are conducted and the result shows that the 14-layer jute/cotton composite has optimum properties achieved and also observed that 90° has better properties than the others cutting angles. Statistical analysis of composites was done by ANOVA-table; based on mean effective plots, the optimum levels of parameters have been identified, and significant contribution of parameters is determined by analysis of variance Also, failure morphology analysis is done using a scanning electron microscope (SEM) through which the internal structures of the tested specimen are analyzed. [ABSTRACT FROM AUTHOR]

Modified composites, blends, polymers and copolymers are some of those engineered materials which are playing a major and remarkable role in achieving our present sustainable environment. Mechanical, electrical, and biological properties of carbon and native metal nanoparticles are distinctive from others and provide plentiful scaffolds for a wide-range of applications in our lives, including medical devices, pharmaceutical, polymer industry, biomedical field, coating of kitchen appliances, food packaging, clothing, gifts, optical devices, biosensors, antimicrobial objects etc. Distinct chemical and physical properties of silver and carbon-based NPs are considered to act in this way. The antimicrobial and conducting nature of Gr and AgNPs are studied here. There is a vast history of these properties; however, beginners still have a bright future. The antimicrobial activity of these two incorporates antibacterial, antifungal, antiviral, anticancer, antioxidant, antistatic and antibiotic nature. Additionally, both nanomaterials exhibit notable thermal conductivity. Based on these characteristics novel composite/blend materials with enhanced electrical, thermal, antimicrobial, antistatic, and antibiotic effect can be engineered with innovative ideas. This paper expresses the worldwide applications of such nanomaterials. [ABSTRACT FROM AUTHOR]

This paper provides a numerical simulation study of Magnetically Circular Layers of Triboelectric Nanogenerators (MCL-TENGs) for energy harvesting and self-powered sensing. The MCL-TENGs generate electrical energy by means of the conversion of mechanical energy into electrical energy through contact electrification and electrostatic induction. This paper concentrates on the numerical modeling of the copper/aluminum MCL-TENG and compares simulation results with experimental findings. The voltage comparison of copper MCL-TENGs (OC) between experimental and numerical simulations at 2000, 2500, and 3000 rpm showed Cu-EXP configuration voltages ranging from 4.1 to 4.4 V and Cu-FEM setup voltages ranging from 4 to 4.4 V. Meanwhile, aluminum MCL-TENGs showed Al-EXP configuration voltages ranging from 4.08 to 4.35 V and Al-FEM setup voltages ranging from 4 to 4.3 V across the third layer. The system can enhance the energy efficiency and sustainability of coastal bridge infrastructure by harvesting surplus energy from mechanical motion and converting it to electricity for self-powered sensing and monitoring systems. [ABSTRACT FROM AUTHOR]

In this paper, a failure analysis of the TMT90m + composite wind turbine blade performed by combining numerical simulation and full-scale destruction tests is presented. The complex failure characteristics of the skin were studied in detail and a driving relationship was obtained. From the results, it was found that the stress concentration leading to local buckling was due to the geometric and layup nonlinearities of the destruction region. This in turn contributed to the successive occurrence of matrix failure and fiber failure. Further, by using the method of finite element secondary development, the accuracy of four commonly used failure criteria for wind blade failure prediction is discussed. From the results, it was found that the Chang-Chang model has ideal prediction accuracy and is more suitable for engineering applications in blade structure design. [ABSTRACT FROM AUTHOR]

With the development and depletion of shallow coal resources, deep coal mining has gradually become normalized. In the face of increasingly severe corrosion environment of coal mining, it is urgent to develop new materials with excellent corrosion resistance for key parts of coal mining equipment. In this paper, SiC, Al2O3 and SiO2 were used as raw materials to prepare three-dimensional network configuration SiC ceramics by organic foam impregnation method. Then the three-dimensional network configuration SiC-Fe composite was prepared by atmospheric pressure casting process. And by electrochemical test, static immersion corrosion test, scanning electron microscope and first-principles simulation calculation, the corrosion resistance of three-dimensional network configuration SiC-Fe composite in harsh mine water environment was characterized, meanwhile the corrosion resistance mechanism was analyzed. The results show that the corrosion potential increases from - 495.756 mV to -379.626 mV, and the corrosion current density decreases from 3.6864 μA/cm2 to 2.1709 μA/cm2 when the SiC ceramic reinforcement is added. The inhibition efficiency based on polarization curve measurement is increased by 41.11%. The charge transfer resistance increases from 5417 Ω·cm2 to 6437 Ω·cm2, and the capacitance value drops from 159.96 μF·cm−2 to 90.12 μF·cm−2. The inhibition efficiency based on electrochemical impedance spectroscopy is increased by 18.83%. First principles calculations show that the addition of SiC reinforcement showed a greater resistance in preventing the migration of corrosive media to the surface of the Fe substrate and can effectively slow down corrosion, which was consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The bumper is an automotive part act as a protective shield in the vehicle. It bears and absorbs the load when the vehicle incurs a collision. If the bumper has got more weight it leads to more fuel consumption and decreases the fuel efficiency of the vehicle. This problem can be overcome by reducing the weight of the bumper without compromising its performance. The main objective in bumper design and fabrication is that it should possess less weight and at the same time, it should withstand the higher load during a collision. In this paper, the properties and performance of the developed bumper composite are compared with the existing bumper. The bumper performance is optimized using a finite element analysis with ANSYS R15.0. From the cost analysis, it has been observed that the weight and cost of the Basalt composite bumper is 49% and 56% lesser than the steel bumper. The Impact strength and Factor of Safety values of the Basalt fabric composite bumper is 47.6% and 32.5% higher than the steel bumper. The total deformation of the Steel bumper is 15.7 mm, and the Basalt composite bumper is 32 mm, which shows 51% higher deformation than steel. [ABSTRACT FROM AUTHOR]

This study uses an incipient wet impregnation method to look into the structural and dielectric properties of Bentonite that have been changed by adding different amounts of Ce and Zn. X-ray diffraction (XRD) analysis showed that the montmorillonite phase was the most common in Ce- and Zn-doped bentonite. Silicon dioxide (SiO2) and quartz (Q) were also found. Scanning electron microscopy (SEM) demonstrated enhanced platelet aggregation and porous structures in doped compounds. Energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of Si, Al, Na, Ce, Zn, Ca, Mg, Cl, Fe, and K elements. Dielectric analysis, focusing on frequency and temperature dependence, unveiled an inverse relationship between frequency and the dielectric constant. Additionally, a strong correlation between temperature and dielectric properties was established through regression equations, indicating an increase in dielectric constant with temperature. Electric modulus analysis showed dispersion at high frequencies, suggesting charge carrier mobility. The AC conductivity analysis showed that the conductivity consistently decreased as the temperature rose. There were clear frequency-independent plateaus and intrinsic charge carrier relaxation that were seen. A fitting analysis showed that charge carriers hopped and the dielectric relaxed, and adding Ce and Zn made the material less conductive. The novelty of this paper lies in its focus on examining the dielectric characteristics of doped materials based on bentonite, particularly concerning the incorporation of Zn and Ce. Highlights: Investigation of structural and dielectric properties of Bentonite modified with Ce and Zn. Utilization of incipient wet impregnation technique for modification. Enhanced platelet aggregation and porous structures observed in doped compounds via SEM. Dispersion at high frequencies indicated by electric modulus analysis. Decrease in conductivity with rising temperature observed in AC conductivity analysis. Charge carrier hopping, and dielectric relaxation mechanisms identified through fitting analysis. Incorporation of Ce and Zn resulted in reduced conductivity in the materials. [ABSTRACT FROM AUTHOR]

This paper examines the microstructure evolution and thermal properties of Al/Ti composites with different volume fractions of Ti. The laminated composites were first fabricated by the accumulative roll bonding (ARB) process. The fabricated composites were then stacked and bonded together by cold roll bonding process to produce Ti–Al functionally graded composite. The microstructural investigation of ARBed composites revealed that plastic instabilities including necking and rupture took place within composites. As a result, the fragments of Ti were distributed uniformly across the Al matrix. In addition, the SEM images of the Al–Ti functionally graded composite showed a compositional gradient from the Al side to the Ti side. Based on the EBSD maps taken from Al and Ti layers, the grain refinement was successfully achieved during six passes. Besides, with an increase in the volume fraction of Ti, the grains became finer, indicating the gradient in grain size across Al–Ti functionally graded composite. Furthermore, the experimentally measured thermal properties of Al and Ti sheets increased as a function of temperature while they declined by increasing passes. However, thermal conductivity, thermal diffusivity, coefficient of thermal expansion, and specific heat capacity of Al/Ti composites showed a reduction with the rise of Ti content. [ABSTRACT FROM AUTHOR]

The development of thermal energy storage materials applied in various fields has been attracting considerable attention in recent years. In this paper, a series of 1,6-hexanediol (HDL)/silicon dioxide (SiO2) form-stable composite phase change materials (fs-CPCMs) with various mass percentage of HDL loadings were made through sol–gel technique. For HDL/SiO2 fs-CPCMs, HDL was served as PCM, and silica gel was acted as the supporting matrix to keep a stable state without leakage of the composites even the temperature was over 85 °C. The results from form-stability test and DSC measurements showed that the as-prepared fs-CPCM with the mass fraction of HDL at 70 wt% presented good form-stability, suitable melting point (43.5 °C), and reasonable fusion enthalpy of 130.9 J/g. Fourier transform infrared (FT-IR) spectroscopy indicated that only physical adsorption existed between the HDL and silica gel. Moreover, the thermal performance tests showed that the thermal energy storage and release rates of the as-prepared HDL/SiO2 fs-CPCM was enhanced compared to pure HDL. In summary, the as-prepared fs-CPCMs exhibit reasonable latent heats, good thermal stabilities, and reliability, which are promising candidates for energy-saving construction materials. [ABSTRACT FROM AUTHOR]

The paper presents a method for the synthesis of metal pastes and diffusion-hardening alloys based on gallium by intensive vibrational mixing of powder components: solid gallium and a complex of filler powders. Using this method (with a specially selected fractional composition of powdered components), a series of samples of Cu–Ga–Sn alloys were obtained—one of the "classic" systems used (with various additives) as metal solder adhesives and dental filling materials. Structural, thermochemical (DSC), physical and mechanical properties, phase composition of initial and hardened samples are presented. When mixing, dosing and storing the components of the initial powder mixture, there is no noticeable segregation, contact-reactive melting of the components. The production of gallium pastes in this work includes the synthesis of the liquid metal component in situ, in the process of vibration treatment of the powder mixture. In addition to ease of use, this method, apparently, can provide new opportunities for the design of the structure of gallium pastes, putties, hard metal solder adhesives and filling materials. [ABSTRACT FROM AUTHOR]

Nanocellulose-based materials have attracted the scientific community's attention due to their abundance in nature, biocompatibility, high surface area, high strength, low toxicity, and low production cost. These environmental-friendly materials have potential applications for developing hydrogels, aerogels, electrodes, adsorbents, packaging films, membranes, nano papers, filters, biomaterials for biomedical, and composites. The present work monitors scientific reports and patent databases of recent achievements on nanocellulose-based composites used as sorbent materials. Most of the pieces found used non-wood, wood, agro-waste, and microorganism sources to obtain nanocellulose. The search identifies most applications were for removing dyes, heavy metals, odor, organic particles from water, and absorption of hemoglobin and immunoglobulin. In addition, it was possible to confirm fifty patent applications on nanocellulose-based sorbent composites. This review was relevant to evaluate the potentiality of applications about nanocellulose as a based sorbent in composites, giving a systematic overview of what has been made and what could be the new potential sources and applications that would be used in future works of this material. [ABSTRACT FROM AUTHOR]

An analytical model of the interaction between Al and C atoms at the interfaces formed by carbon nanoparticles and aluminum is proposed. The model is convenient for practical use in calculating the free energy of the interface, which is essential for nanocomposites and determines their mechanical, thermophysical, and other properties. The paper considers nanoparticles of various structures that are used in the development of aluminum matrix composites: fullerenes of various diameters, single-layer carbon nanotubes of metal and semiconductor types of various radii and chirality, graphene, and graphite. The proposed model employs the Lennard–Jones potential and approximately takes into account the effect of the local structure of the nanoparticle on the interaction of pairs of aluminum and carbon atoms using additional parameters. In this paper, we assume that the average local curvature of the nanoparticle surface determines the depth and location of the potential well. The work is supplemented with the study of interphase interaction in the framework of the density functional theory. The comparison of the results of calculations performed using approximations of various levels of accuracy is used to establish the limits of applicability of the proposed potential, and the possibility of its application in the study of interfacial interaction in nanocomposites based on aluminum and nanocarbon is shown. [ABSTRACT FROM AUTHOR]

Porous materials are pivotal in emerging fields like tissue engineering, scaffold, and drug delivery due to their distinctive porosity-driven functional properties. This paper describes how to achieve multiscale porosity in food-based composites through a thermally activated gelatinization process of amylopectin molecules coupled with 3D printing. By controlling printing paths, macropores are engineered, while degree of gelatinization governs micro- and nanopores formation. Process-microstructure relationship reveals that longer preheating treatments at higher gelatinization temperatures significantly reduce micro-pore area by over twofold and nanopore surface area by over threefold. These results provide a promising route to fabricate food-based composite with tailorable microstructures. [ABSTRACT FROM AUTHOR]

Improving the mechanical properties of high-conductive materials like pure copper without any serious adverse effect on their conductivity attracts more interest in several industries. The aim of this paper is to investigate the mechanical behavior and fracture mechanisms of the copper matrix composites reinforced by steel nanoparticles under tensile, fatigue, and impact loading regimes. Scanning electron microscopy is used to study the fracture mechanisms of the copper matrix composite samples. The fatigue test results show that reinforcing the pure copper with 2.5 wt.% steel nanoparticles improves the fatigue life of the pure copper by 67, 31, and 86 percent in 60, 80, and 100 MPa amplitude stresses, respectively. The results of the tensile tests of the composite samples also show that the composite reinforced by 2.5 wt.% steel nanoparticles has the best combination of tensile and yield strengths and elongation among the present composite grades and pure copper. Further increasing the reinforcement particle content to 5.2 and 7.5 wt.% deteriorates the mechanical strength and fatigue life. However, ductility and almost impact energy increase gradually by increasing the steel nanoparticles' weight percent in the composite grades. The mechanical behavior and fracture mechanisms are validated using micrographs of the fracture surfaces of the test samples, and the micrographs confirm and justify the test results obtained by the mechanical tests. [ABSTRACT FROM AUTHOR]

Mobile communications systems are affected by what is known as fading, which is a well-known problem largely studied for decades. The direct consequence of fading is the complete loss of signal (or a large decrease of the received power). Rayleigh fading is a reasonable model for wireless channels although, Nakagami-m distribution seems better suited to fitting experimental data. In this paper we obtain the Nakagami-m distribution as a composite (mixture) of the Rayleigh distribution, a result which as far as we know it has not been shown in the literature. This representation of the Nakagami-m distribution facilitates computations of the average BER (Bit Error Rate) for DPSK (Differential Phase Shift Keying) and MSK (Minimum-Shift Keying) modulations for this distribution and higher moments of them, which is of great applicability to modeling wireless fading channels. Furthermore, a simple, not depending on any special function, apart of the Gamma function, bivariate version of the Nakagami-m distribution is also proposed as a special case of the multivariate version which is also presented. The proposed composite distribution is simulated through the standard procedure of summation of phasors, and results for the new closed-form measures for the MSK modulation are also shown. From that it is clear that the alternative formulation of the Nakagami-m distribution allows for easier modeling of fading fading-shadowing wireless channels through the new explicit second order statistics metrics. is well suited for modelling fading-shadowing wireless channels. [ABSTRACT FROM AUTHOR]

The paper proposes a two-dimensional thermokinetic model of the composite synthesis process in the mode of dynamic thermal explosion taking into account the structurization of the synthesis product. Structurization in the model is understood as a transition from amorphous to crystalline state. The model takes into account the heating of the reactor walls by thermal radiation from the device, the temperature of which can vary at different rates. Chemical reactions are described by a summary scheme that corresponds to the synthesis of Ni3Al composite. The kinetic law takes into account a possible strong inhibition of the rate of the reaction with the accumulation of the synthesis product, which is typical for reactions controlled by diffusion at the particle level. The effective thermophysical properties of the components of mixture and reaction products in the reactor depend on the properties of the constituents of the initial mixture and the fraction of reaction product. The properties of the latter also depend on the degree of structurization. The structurization process is described by a special additional parameter whose evolution is modeled by a reversible reaction. It is assumed that the structurization process starts from the moment of product appearance and continues during the cooling of the system. It is shown that synthesis results in the formation of a composite containing the initial components and the reaction product with the matrix partly in the amorphous state and partly in the structured state. The dynamics of synthesis and structurization are influenced by heating conditions and reactor size. [ABSTRACT FROM AUTHOR]

Inspired by nature, various biomimetic materials have been synthesized for enhanced mechanical properties, among which composites with brick-and-mortar structures attract the most attention. In such bio-inspired composites, the matrix layer mainly functions to transfer load between bricks through shearing, while the shear stress in the matrix is not uniform but highly concentrated on the interface ends, which tends to initiate cracks and evoke interface delamination in composites. To enhance the composites’ resistance to interface delamination, we propose to homogenize the shear stress by adopting a matrix with a gradient modulus. A theoretical solution to the optimal gradient modulus of the matrix layer is obtained, followed by computational validations. Moreover, composites with such functionally graded matrices are further demonstrated to possess higher elastic limits, higher resilience, and flaw tolerance than the uniform controls. The results of this paper should be of great value to the design and synthesis of advanced structural materials for superior mechanical performance. [ABSTRACT FROM AUTHOR]

Composite materials are very attracting in both aerospace and automotive applications because of their exceptional strength, stiffness-to-density ratio, and superior physical properties. However, these materials are susceptible to damage, necessitating effective repair techniques to maintain their structural integrity and extend their operational life. Due to the high production costs for every single component in carbo-resin, further repair techniques have been developed to repair damaged components of a complex structure on site without having to disassemble any element. In this scenario, the scope of this research paper is to implement an innovative repair procedure to be carried out on-site. The hot bonding process was used for the scope, and two different technologies involving both the prepreg and the dry patches impregned on site (infused) were proposed. Firstly, the composite panels were manufactured, and then they were analysed through non destroying evaluation techniques. The mechanical behaviour of the samples (under both the pristine and the repaired conditions) was evaluated through open hole tensile and compression tests aiming to assess their properties under maximum stress conditions. Impact tests at penetration and at indentation were conducted to study the performances under dynamic loading. Despite an increase of voids percentage was proved for the dry patches impregned panels (+ 33%), better mechanical properties were found for the infused specimens compared to prepregs (+ 8% and + 10% under compression and tensile loads, respectively), proving the effectiveness of the developed process. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach using Generative Adversarial Networks (GANs) to predict thermal stress distribution in binary composites. The composite plates, generated randomly, serve as the basis for finite element simulations that produce datasets for training the GANs. To enhance the training process, binary images representing composite architecture are combined with corresponding thermal stress distribution images, creating a unified dataset. Remarkably, the trained GANs exhibit a high level of accuracy in predicting thermal stress within the composites. The results underscore the potential of GANs in accurately predicting thermal stress, opening avenues for advancements in materials science. [ABSTRACT FROM AUTHOR]

This paper presents a groundbreaking strategy for optimizing composite laminate structures by integrating finite element modeling with a specialized multi-layer neural network. The neural network is trained on precise ground truth data obtained from rigorous finite element simulations, allowing it to discern intricate correlations among layer orientations, boundary conditions, and optimized designs. Tailored to the nuances of laminar composite optimization, the developed neural network emerges as a potent predictive tool, providing deep insights into the intricate interdependencies of design parameters. The study's findings hold immense promise for advancing materials design and structural engineering, highlighting the transformative potential of combining computational intelligence with traditional modeling approaches. [ABSTRACT FROM AUTHOR]

The paper investigates the normal interaction between the steel striker, carbon fiber and aramid fiber reinforced plastic plates at a speed ranging from 166.6 to 184.2 m/s. A series of physical and numerical experiments with impact load is conducted to design a mathematical model and numerical algorithm for the composite plate. The behavior and fracture of composites are described by the elastic-brittle model accounting for their different compressive and tensile strengths. The numerical simulation utilizes the finite element method in the EFES software developed by the authors. [ABSTRACT FROM AUTHOR]

With the rapid development of economy and society and the rapid advancement of industrialization and urbanization, the sewage discharged in the daily life of urban residents and the wastewater produced by industrial enterprises contain a large number of organic pollutants. Such organic pollutants are easy to flow into urban rivers through surface water, causing serious pollution of water environment, and thus adversely affecting the sustainable green development of cities. In recent years, the degradation of rhodamine B (Rh B) wastewater has become the focus of research on the treatment of refractory organic wastewater. In this paper, alkaline lignin was used as the precursor, and CQDs with fluorescence effect were prepared from bottom to top by hydrothermal method; Bi2WO6 was combined with Bi2WO6, and Bi2WO6/CQDs composite material was prepared to degrade organic pollutants into low-toxicity or non-toxic small molecules, as an effective way to solve the pollution of solar energy resources and environment. Carbon quantum dots (CQDs) have the advantages of excellent electron conduction and optical properties, non-toxicity and good biocompatibility, which will be more conducive to improving the light utilization rate of Bi2WO6 and inhibiting the recombination of electrons and holes, so as to improve its photocatalytic performance. The composite materials were characterized by XRD, FT-IR, TEM, and UV–Vis, and the results confirmed the successful preparation of Bi2WO6/CQDs using a simple hydrothermal method. The introduction of CQDs can reduce the bandgap width of Bi2WO6, thereby improving the absorption of light and promoting photogenerated electron transfer. Under visible light irradiation (300-W xenon lamp, λ > 420 nm), the amount of CQDs was 30 ml, and the degradation rate of Rh B was 86.96% within 120 min. Due to the excellent upconversion photoluminescence, as well as the photoinduced electron transfer and reservoir properties of CQDs, the Bi2WO6/CQDs composite exhibited superior photocatalytic performance in the degradation of Rh B under the irradiation of simulated solar light. This study provides a strategy for the development of high-performance catalysts based on CQDs. [ABSTRACT FROM AUTHOR]

Ingots of a composite with a Fe−Cr–Mn–Mo–N–C matrix and reinforcing particles in the form of MgO, Al2O3, and AlN conglomerates have been produced by aluminothermy, which is a version of self-propagating high-temperature synthesis (SHS). The ingots differed mainly in carbon content. It has been found that with an increase in carbon content in the composite from 0.01 to 0.50 wt %, its hardness rises from 238 to 271 HV and its wear resistance improves. The wear resistance has been estimated by abrasive testing under the conditions of dry friction between the sample and a fixed abrasive−electrocorundum Р400 grit (28–40 μm) and Р80 grit (200–250 μm) abrasive paper. As a measure of wear resistance, we chose a decrease in sample weight after tests. The pressure with which the test material acted on the abrasive was roughly equal to 0.25 N/mm2, and the test time was 90 s. The loss in weight was been measured using VLR-200 balance. The hardness has been measured by Vickers hardness testing using an ITV-1-A hardness meter according to State Standard 2999-75 with a holding time of 10 s under a load of 30 kgf. It has been found that a rise in carbon content in the composite causes its embrittlement. It is noteworthy that in passing compressive strength tests samples with 0.01 and 0.16 wt % C remained intact, whereas those with 0.50 wt % C cracked. However, cracked samples continued deforming without complete breakdown up to a load that is maximum permissible for the test machine. The compressive strength has been estimated from the cracking load and has been found to be 3210 MPa. The ultimate compressive strength has been determined using an REM-100-A-2 multipurpose testing machine. [ABSTRACT FROM AUTHOR]

Sulfur dispersion and its electrical conductivity are the key for lithium-sulfur batteries with good cycling stability. In this work, a flexible film composed of reduced graphene oxide (rGO) and sulfur is fabricated from the self-assembly aggregation of sulfur-coated rGO sheets. Not only the three-dimensional rGO network enormously improves the electrical conductivity of the film, but also the strong interaction between well-dispersed sulfur molecules and rGO sheets ensures the stability of sulfur during charge/discharge. Furthermore, the rGO/S film can be directly used as cathode without any binders, conductive additives, and aluminum current collectors. The electrochemical result shows that the rGO/S film has excellent cycling stability with a high rate capacity 485 mAh/g at a current rate of 2C. [ABSTRACT FROM AUTHOR]

In this research, the role of B4C-reinforcing particles on the corrosion behaviour of Al5083/B4C nanocomposite has been investigated. Al/B4C nanocomposite powder with weight percentages of 3 and 7 of reinforcing phase was prepared by mechanical milling method. The resulting powder was initially hot-pressed and then hot-extruded. The microstructure of the sample was studied using scanning electron microscopy and their corrosion behaviour was studied using potentiodynamic polarization and scanning electrochemical impedance spectroscopy methods in different immersion time intervals. The results showed a uniform distribution of reinforcing particles and also the scattering of intermetallic particles at the surface of the samples. However, increasing the content of B4C particles in the composite samples enhances the cathodic and anodic reactions by increasing the content of intermetallic particles as cathodic sites on the surface, so that higher corrosion current density is observed in the composite samples with 7 wt% B4C. Finally, it was concluded that increasing the value of B4C decreases the corrosion resistance of the B4C-reinforced composite samples in sodium chloride solution, which makes it unsuitable in marine applications. [ABSTRACT FROM AUTHOR]

Adsorption has been reported to be optimal among oil spill cleanup methods due to its simplicity, low capital and operational cost, high removal efficiency and environmental friendliness. However, its continuous usage has been linked to generation of enormous waste, after oil spill cleanup, to which use of reusable oil sorbents has been proposed as a possible solution. Synthetic organic oil sorbents have high mechanical properties compared to other categories of oil sorbents, but they suffer low adsorptive capacities. To address this problem, among other nanoparticles, rGO have been infused in polymeric materials to produce composite oil sorbents characterized with high adsorptive capacities. In this research, surface modified rGO was infused in waste expanded polystyrene, to produce electrospun PS/FrGO composite sorbents by solution blending and electrospinning method. Adsorptive capacities of produced composites were evaluated in four oil samples. Functionalization of rGO was found to cause removal of residual oxygen containing functional groups such as hydroxyl (–OH), and resulted in more hydrophobic surface. Infusion of FrGO, in waste expanded polystyrene resulted into composites with increased surface area, from 71.50 m2/g for pure PS20 to 353.45 m2/g, 429.18 m2/g, 456.14 m2/g for PS20 infused with 1, 2 and 4wt% of FrGO. Increase in oil sorption capacities of the composite, observed in four oil samples corresponds to improved surface area. Produced composites show good recyclability in the four oil samples, at least up to the third sorption cycle. Highlights: Modification of Graphene oxide (GO) to reduced Graphene Oxide (rGO) rGO was functionalized and infused in Polystyrene (PS) to form PS/FrGO composite PS/FrGO composite was applied to oil–water mixture for oil adsorption Reusability of composites produced was evaluated. [ABSTRACT FROM AUTHOR]

Zinc chloride–activated carbon (AC) and nano zinc oxide/activated carbon composite (NZAC) as solid adsorbents were synthesized from date palm fronds (DPF) as a green material of activated carbon, while zinc oxide nanoparticles (NZ) were prepared in the presence of polyethylene glycol as capping agent. All the prepared solid adsorbents were investigated by several characterization techniques such as thermogravimetric analysis (TGA), nitrogen adsorption/desorption isotherm, Fourier transform infrared spectroscopy (FTIR), pH of point of zero charges (pHPZC), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The NZAC sample had the highest total pore volume (0.960 cm3/g), specific surface area (2085.47 m2/g), and with pHPZC of 7.8. Adsorption of methylene blue was tested by Langmuir, Freundlich, and Temkin adsorption isotherms. NZAC had the highest Langmuir adsorption capacity (456.62 mg/g) at 40 °C with a dimensionless separation factor (RL) of 0.030. MB adsorption matched well with pseudo-second-order and Elovich kinetic models. The entropy, free energy, and heat changes for MB adsorption onto NZAC were found to be 0.0243 (kJ/mol. K), − 3.5589 (kJ/mol), and 3.561 (kJ/mol), respectively. Thermodynamic analysis demonstrated that the adsorption process of MB is favorable, spontaneous, physisorption, and endothermic. Desorption studies showed that HCl (0.01 mol/L) achieved the higher desorption percent (87%) compared with the other eluents. [ABSTRACT FROM AUTHOR]

Terephthalic acid (TPA) was recovered by alkaline hydrolysis of waste polyethylene terephthalate (PET) bottles. TPA recovered was used to prepare Sn-based catalyst by solvothermal method. For comparison, commercial TPA was also used to prepare Sn-based catalyst. The catalysts were used for the electrochemical reduction of CO2 to formate. Both the catalysts were found to possess nanoflake morphology, and were highly porous in nature with Brunauer–Emmett–Teller (BET) surface area of 211.4 and 239.4 m2/g for commercial and PET derived TPA-based Sn catalysts, respectively. The catalyst made from the waste PET bottles derived TPA was found to be more effective than the one obtained from the commercial TPA. The Faradaic efficiency obtained for the formation of formate was 68.4% at potential − 1.8 V (vs Ag/AgCl) and current density of 13.5 mA/cm2, when catalyst was synthesized using waste PET derived TPA. High activity of the electrocatalysts was attributed to higher capacitance, and lower resistance of the catalysts. [ABSTRACT FROM AUTHOR]

Six types of γ-polyglutamic acid (γ-PGA)/cold water-soluble starch (St) composite film models were constructed using molecular dynamics simulation, and their properties were investigated and compared with the corresponding experimental values. The compatibility between the composite film components was analyzed using the radial distribution function and mean square displacement (MSD). The hydrogen-bond number and bond energy were used to track the film-formation process. The mechanical property data of the films were extracted, and MSD was used to analyze the permeability of the film to carbon dioxide, oxygen, water vapor, and carbon-16 saturated fatty acids. Finally, the simulated values of mechanical properties and permeability were compared with the experimental values. The results demonstrated that γ-PGA is well compatible with St. The intramolecular and intermolecular hydrogen bonds of γ-PGA and St did not change considerably during the film-formation process. The simulated values of the mechanical properties exhibited a similar trend as the experimental values; however, in terms of permeability, a difference was observed between the initial values of the simulated design and actual material parameters, as well as the complexity of the experiment. [ABSTRACT FROM AUTHOR]

Herein, a study on the chitosan-amalgamated gold nanoparticles (AuNPs)- and silver nanoparticles (AgNPs)-based molecularly imprinted polymer (MIP) film and its application to recognize/remove ciprofloxacin (CIP) antibiotic in real samples is reported. The pomegranate peel at pH 8 is used for the reduction of silver nitrate solution to form AgNPs, whereas chitosan itself is used for the reduction of gold chloride solution to form AuNPs. The size of the synthesized AgNPs and AuNPs is in the range 30–45 and 45–50 nm, respectively, which is determined by dynamic light scattering (DLS). Further, the synthesized nanoparticles (NPs) are used to prepare MIP film. The molecularly tailored chitosan-based nanocomposite is used as a functional biopolymer to enhance the adsorption capacity and surface area of MIP film. The properties of synthesized chitosan-based AuNPs- and chitosan-based AgNPs-MIP composite (Chi@AuMIP and Chi@AgMIP) exhibited much higher adsorption capacity than non-imprinted polymer (NIP). The results revealed that the theoretical equilibrium constant (KL) and maximum adsorption capacity (Qmax) found by the Langmuir model are 12.2 and 20.48 mg g−1 for Chi@AuMIP and 18.31 and 34.13 mg g−1 for Chi@AgMIP, respectively. The recovery percentage of CIP for Chi@AuMIP and Chi@AgMIP is 98 and 80%, respectively. The selectivity experiment data suggest maximum adsorption capacity for targeted molecule (CIP) by the MIP as compared to analogs of template molecule. MIP showed relative potential selectivity and good recovery percentage for CIP in real samples as well. [ABSTRACT FROM AUTHOR]

Eggshell, a readily available natural material, possess remarkable properties that enhance the mechanical and tribological performance of composites, as evidenced by numerous studies. However, a scientometric analysis specifically examining the research landscape of eggshell-based composites has not been previously conducted. This study addresses this gap by employing a data processing, mining, analysis, presentation, and contemporary visualization approach to analyze bibliographic data on the effects of eggshell in composites. This analysis aims to inform researchers and guide future research directions in this promising field. Scopus data was utilized for the scientometric analysis, which encompassed publishing sources, leading authors, frequently used keywords, key publications, and the countries with the most significant contributions. The analysis revealed that “eggshell” is a prominent keyword within the field. Additionally, “Key Engineering Materials” emerged as a publication source with a high number of citations and articles. Notably, India was identified as the leading country in terms of research output. The graphical and quantitative representation of researchers and nations presented in this study facilitates knowledge sharing and fosters collaborative research efforts among academics. Furthermore, this study strengthens the evidence for eggshell potential to improve the mechanical and tribological properties of composites across diverse applications. However, it is crucial to acknowledge that the pre-treatment method and composite composition significantly influence the final material’s strength and durability.Article Highlights: Nature-derived materials, such as eggshell, hold immense promise for utilization as bio-ceramics in composites, paving the way for the development of environmentally friendly products. Numerous studies have explored the use of eggshell as a composite material to address environmental concerns. Eggshell exhibit unique characteristics that enable them to serve as replacements for conventional friction materials, thereby mitigating the generation of wear debris that poses detrimental environmental impacts. [ABSTRACT FROM AUTHOR]

Aluminium (Al) matrix composites are widely used in the automotive and aerospace sectors due to their low density, high specific strength, and excellent tribological performance. Although wear studies on Al matrix composites started approximately 40 years ago, they still continue to attract. This review reports the latest developments on the wear performance of up-to-date Al matrix composites. For this reason, the effect of different factors such as applied load, sliding speed, sliding distance, temperature, particle content, and particle size on tribological performance was investigated, considering the coefficient of friction and wear rate. Dominant wear mechanisms depending on wear parameters were also evaluated. Consequently, the review provides the challenges and future research directions in the tribology of Al matrix composites. [ABSTRACT FROM AUTHOR]

This study introduces the possibility of using polyaniline as a thermally conductive filler in the manufacturing process of composites using epoxy. Compared to conventional thermally conductive fillers, polyaniline is a material with a simple synthesis process and is cost-effective. In this experiment, among various types of polyaniline, polyaniline in the form of an emeraldine salt (ES) doped with protons and polyaniline in the form of a dedoped neutral emeraldine base (EB) were used as the thermally conductive filler. ES doped with protons show higher electrical and thermal conductivity than EB due to the conductive polymer characteristics in which the thermal conductivity increases as the electrical conductivity increases. We put both fillers into the widely commercially available diglycidyl ether of bisphenol A (DGEBA) epoxy composite, and analyzed the effect of the thermal conductivity of the filler increased by doping on the thermal conductivity of the composite, and analyzed the possibility of use as a thermally conductive filler. The epoxy resin without filler was measured to have the thermal conductivity of 0.21 W/m K, the thermal conductivity of the composite reinforced with EB filler was measured to be 0.27 W/m K, and the thermal conductivity of the composite reinforced with ES filler was measured to be 0.29 W/m K. The results confirmed that the input of polyaniline as a thermally conductive filler could improve the thermal conductivity of the composite, and also confirmed that the proton-doped ES filler showed higher thermal conductivity than the neutral EB filler. Through this study, we highlight the possibility that polyaniline can be used as a promising thermally conductive filler for various composite materials. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) and regenerated cellulose (RC) are valuable natural polymers, which are promising materials for a green future. They can be combined to fabricate a biocomposite, but incompatibility between them can result in undesirable properties. The objective of this work is to assess the compatibility between deproteinized NR-grafted methyl methacrylate (MMA) and RC in their composite fabricated by co-precipitation. Graft copolymerization of MMA onto deproteinized NR was carried out in the latex stage using tert-butyl hydroperoxide and tetraethylenepentamine as radical initiators at 30 °C. The composites were prepared from grafted NR latex and cellulose solution in urea/NaOH/water by co-precipitation method, followed by hot pressing. The chemical and crystal structures of two phases in the composites were characterized by attenuated total refection Fourier transform infrared radiation, proton nuclear magnetic resonance and X-ray diffraction. The improvement in thermal stability of the composite has been demonstrated by thermal gravimetric analysis. A reduction in RC phase size and a smoother interface of the MMA-grafted composites compared to ungrafted samples were observed via scanning electron microscopy. Differential scanning calorimetry showed glass transitions of the composites increased steadily with increasing RC contents, from − 63.47 to − 63.2, − 63.07 and − 62.82 °C at respective 0, 10, 20 and 30% RC. These results indicated that enhanced compatibility between NR and RC has been obtained after modifying NR by graft-copolymerization method. [ABSTRACT FROM AUTHOR]

To address the global environmental pollution problems, the application of biodegradable agricultural waste as a reinforcing material in the development of composite materials is one of the prominent solutions for sustainable development. Following that in the present investigation, a hybrid epoxy–based composite is fabricated using banana and glass fibers as reinforcing materials for lightweight structural applications. The main purpose of this research article is to utilize banana fiber (a biodegradable agricultural waste) as a reinforcing material in composite fabrication because of its low cost, non-abrasive, and eco-friendly nature. Herein, the fabricated composite material was characterized by various tests such as tensile, flexural, hardness, impact, thermal conductivity, and scanning electron microscopy. The effects of volume fraction and sequence of banana and glass fiber layers on mechanical properties such as tensile strength, hardness, flexural, and impact strengths were also investigated. Our results showed that for sample with alternating layer of banana and glass fibers and 1 wt.% charcoal, the epoxy-based composite exhibited the highest tensile, flexural and impact strengths of about 80.9 N/mm2, 145.4 N/mm2, and 3.5 kJ/m2, respectively. The same sample also reported the highest hardness of 56 VH. Furthermore, with the addition of banana fibers, the thermal conductivity of the laminates also increased. This enhancement in the mechanical and thermal properties with amalgamation of biodegradable banana fiber, strong glass fiber and water-resistant epoxy resin may help in manufacturing of lightweight composite domains for automobile and structural applications. [ABSTRACT FROM AUTHOR]

In recent decades, the greatest challenge facing the world has been protecting the environment from various forms of pollution. Water pollution is one of the most crucial environmental problems threatening living organisms' lives and human health. Mostly anthropogenic, it undoubtedly originates from diverse sources, including agricultural, domestic, and industrial activities. Therefore, adopting sustainable and environmentally friendly practices constitutes an ideal solution for purifying contaminated water to be further used in industrial activities and so on. The valorization of lignocellulosic biomass for the production and conception of value-added products is an attractive and environmentally friendly way of preserving the environment. Lignocellulosic biomass, such as crops, agricultural wastes, forest residues, etc., is a sustainable and plentiful resource that can be valorized and used as robust material for eliminating different pollutants from sewage, including organic pollutants, heavy metals, inorganic compounds, and microorganisms. Indeed, the valorization of biomass wastes is among the most intelligent strategies. It is like killing two birds with one stone: reducing the quantity of biomass waste and benefiting from its physicochemical properties. Feedstocks are rich in cellulose, hemicellulose, and lignin, which have already been proven efficiency in removing persistent pollutants. Moreover, it can undergo physical, chemical, and thermal to prepare cellulose nanocrystals and biochar with high removal ability. The current review discusses the exploitation of lignocellulosic biomass to produce composite materials in the applications of wastewater purification, especially for the removal of different persistent organic and inorganic contaminants. It highlights the recent research studies and the mechanisms involved in eliminating pollutants using lignocellulosic-based materials. [ABSTRACT FROM AUTHOR]

Background: It has been noticed that failure of composite resin restorations can be attributed to either of the two following causes: fracture or secondary caries. For that reason, it is mandatory to formulate a restorative material with antibacterial effect. An octenidine dihydrochloride (OCT) has been assessed as an alternative to antimicrobial material, such as chlorhexidine due to their higher microbicidal effect and less cytotoxicity. Objective: Current study aimed to add different concentrations of octenidine dihydrochloride into experimental flowable resin composite and evaluate its antibacterial activity over different periods of time to provide the manufacturers with more precise information. Methods: A flowable resin composite material mix was formulated. Octenidine dihydrochloride antibacterial material was then added separately to the formulated mix at 1% wt. and 1.5% wt. concentration, respectively. Antibacterial activity was assessed against Streptococcus mutans using agar diffusion test and compared to a commercial resin composite. Results: It showed that by increasing the percentage of incorporated octenidine dihydrochloride (1% and 1.5%), respectively, the antibacterial efficacy against the Streptococcus mutans increased. Results of this study also showed the time had a significant decrease in the antibacterial effect. Conclusions: It can be concluded that by the incorporation of octenidine dihydrochloride (1% and 1.5%), respectively, the antibacterial efficacy against the Streptococcus mutans increased. Time had a significant decrease in the antibacterial effect of OCT. [ABSTRACT FROM AUTHOR]

This study explores the repurposing of waste glass optical fibers (SiO2 fibers) by using them as toughening agents for silicon. The poor fracture toughness of silicon has precluded its development as a structural material and reinforcing it with a second phase such as glass fiber is a potential route for enhancing its toughness. In this work, the focus is checking the extent of toughening brought about by the introduction of SiO2 fibers in the silicon matrix and understanding the reasons for the same. A composite of 79 wt.% silicon and 21 wt.% SiO2 fiber was synthesized by spark plasma sintering at 1473 K at an applied pressure of 75 MPa. The spark plasma sintered composite possessed a relative density of 99%. The silicon matrix and SiO2 fiber reinforcement exhibited an average hardness of 12 GPa & 7 GPa respectively. The indentation fracture toughness of the composite was observed to be 1.55 MPa.m1/2 which is ~ 8% higher than the indentation fracture toughness of nominally pure silicon. The SiO2 fibers were unable to provide sufficient crack deflection or crack blunting and consequently, the enhancement in toughness was marginal. [ABSTRACT FROM AUTHOR]

Glass Fiber Reinforced Polymer (GFRP) is commonly used in outdoor applications that expose it to environmental conditions capable of degrading its properties, notably ultraviolet (UV) radiation. In this study, we subjected GFRP to UV radiation for a duration of up to 180 days in an accelerated aging chamber. The composites underwent mechanical testing through tensile and flexural evaluations, while chemical and physical changes in the composite were assessed using Fourier-Transform Infrared Spectroscopy, Thermogravimetric analysis, and optical microscopy. Tensile tests revealed a noticeable reduction in GFRP strength after just one month of UV exposure, with a decrease of 18.7% observed at 90 days of exposure. In contrast, the behavior of the composite under flexural testing showed an initial improvement in strength after 30 days of UV exposure, with a significant increase of 54.1%. With longer exposure times, flexural strength gradually decreased but remained 18.9% higher than the strength of the unaged composite after 180 days of UV exposure. Other characterizations indicated material degradation, marked by phenomena such as photo-oxidation, composite yellowing, and the appearance of microcracks on the surface. These factors collectively contribute to the reduction in composite strength. Despite the visible degradation, the aged composite may exhibit improvements attributed to post-curing. However, over more extended periods, it may experience a decline in mechanical properties. Consequently, longer degradation times may unveil a behavior pattern distinct from what is observed during shorter periods, contingent upon the specific mechanical load under consideration. [ABSTRACT FROM AUTHOR]

Global economic development and efforts to enhance overall quality of life yielded growth in the construction and building sector, increasing not only the demand for materials but also waste generation. Its efficient management should take full advantage of the exceptional properties of building materials. The presented work is the first reported study on possibly using waste rigid polyurethane (PUR) foam, commonly applied as thermal insulation, as particle-shaped low-density filler for manufacturing hybrid epoxy-basalt composites. It investigated the potential management of waste PUR foam by applying it as a functional filler to hybridize epoxy-basalt composites. Herein, 1, 2, 5, and 10 wt% PUR powder were introduced into the thermoset-based composites prepared using the vacuum bag method. A comprehensive analysis of mechanical and thermomechanical properties correlated with changes in the composite structure revealed the beneficial aspects of the waste filler addition associated with increased heat deflection temperature and mechanical damping ability. Introducing micrometric domains of the waste filler changed the composites' fracture character. It enabled maintaining the impact strength of composites containing up to 5 wt% of PUR powder at the level of unfilled epoxy resin. However, despite that, the incorporation of PUR powder unfavorably affected tensile and flexural performance, yielding a significant drop in moduli and strength. [ABSTRACT FROM AUTHOR]

Fabrication of composite photocatalysts that provide an easy charge transfer mechanism to enhance the photocatalytic activity is a promising approach for the removal of organic contaminants from the water bodies. In this series, for the first time, we have decorated Ni, Pt, and Pd on the surface of hydrothermally synthesized Cu-doped biphasic Bi2O3. The synthesized composites were analyzed using advanced characterization techniques to uncover the physicochemical properties of the materials. The XRD results revealed well crystalline nature of the materials with enhanced particle size as compared to binary composite. The optical analysis showed the improved optical characteristics of ternary composites. The photocatalytic activity was tested against the RhB and observed the ternary materials with enhanced activity when compared with the binary composite and 5 wt% was the optimum loading of the metal on the surface of Cu- doped Bi2O3. Pd decorated samples showed the highest photo removal of RhB where complete mineralization of dye is achieved only in 50 min which is ascribed to the increased absorption and reduced reunion of charge carriers. The effect of pH of the reaction medium and the role of reactive oxygen species were also examined. In the acidic medium, complete degradation of dye is achieved in 10 min only and holes are found prominent active species for the degradation of RhB. The synthesized materials were stable and could be used many times without significant loss in the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Rare earth elements (RRE), due to their unique magnetic, electrical, and optical properties, are an important group of elements demanded in many application areas from machine technology to the health industry. In this study, new composites were obtained by mixing Erbium oxide (Er2O3), one of the rare earth element oxides, into PCL–PEG blend, which is also an important material group, in different ratios. The characteristic functional groups of the obtained polymer blend/Er2O3 nanocomposites were determined by the ATR-IR, and as the erbium oxide ratio increased, characteristic peaks of the polymers in the blend as well as characteristic signals of the Er–O–Er bond were found. When the thermal behavior of the obtained composites was examined, it was observed that the polymer blend exhibited miscible blend properties and the melting temperature of the polymer blend increased as the Er2O3 ratio increased. In addition, it was determined that the thermal stability of the composite increased significantly. X-ray measurements of composites at room temperature support other measurement results. It was determined that the presence of Er-RRE oxide increased the crystal structure feature in the polymer blend composite. Gamma radiation shielding capabilities of polymer materials containing different erbium ratios were investigated by calculating shielding parameters such as half value layer (HVL), radiation protection efficiency (RPE), and mean free path (MFP). Cs-137 and Co-60 radioactive sources were used as gamma sources. According to the obtained measurement results, Erbium oxide increased the absorption property of the polymer composite material. [ABSTRACT FROM AUTHOR]

In this study, an eco-friendly break pad material using sorghum husk-derived Si3N4 and biochar novel friction modifier was development and characterized. The primary objective of this present study was to replace the already used friction modifier such as alumina and graphite with low-cost eco-friendly sorghum husk biomass-derived Si3N4 and biochar. The Si3N4 was synthesized using thermo-chemical process whereas low-temperature pyrolysis was used to synthesis the biochar. The composites were prepared using a compression molding process followed by post-curing at 120 °C. The results of this study revealed that the addition of Si3N4 as frictional modifier improved the mechanical properties. The highest tensile, flexural, impact, compression, hardness, and lap shear strength of 138 MPa, 192 MPa, 6.7 J/m, 152 MPa, 94 shore D, and lap 17 MPa were noted for composite contain friction modifier of Si3N4 and biochar as 12:8 (N4). The SEM images revealed highly reacted phases of reinforcements as well as toughness improved matrix. Similarly, the composite designation N3 with 10:10 friction modifier produced improved wear resistance of 0.12 mm3/Nm of sp. Wear rate and 0.24 of COF. The optical microscope image of worn surfaces revealed waviness for low Si3N4 constant and flat for higher loading. Moreover the thermal conductivity of Si3N4 rich N5 composite (15:5) records the lowest value of 0.214 W/mK. Thus, the replacement addition of Si3N4 and biochar for alumina and graphite is worth full to maintain the brake pad requirements as well as minimize the environmental impact and improve the circular economy. These eco-friendly brake pads developed using biomass-derived friction modifiers could be used in automotives, electric motors, e vehicles, and bicycles. [ABSTRACT FROM AUTHOR]

Background: This research was done to evaluate the bond strength using two repair methods with lithium disilicate ceramic. Methods: Cojet and clearfil repair methods were used to repair lithium disilicate ceramic. The ceramic was sliced into slices before sintering (30 samples). Vita Ambria (Vita, Zahnfabrik, Germany) ceramic was used, surface-treated with the 2 repair systems and then bonded to composite. Samples are stored, thermocycling was done, and then, shear loading was done until fracture. Bond strength values were collected and statistically analysed. Results: The results showed that the cojet surface treatment showed significantly more bond strength (14.43 ± 1.46 Mpa) than the clearfil surface treatment showing (4.16 ± 1.33) as indicated by paired t-test p ≤ 0.05. Conclusions: Bond strength between composite and the ceramic Vita Ambria is better using cojet surface treatment than using the clearfil system. [ABSTRACT FROM AUTHOR]

In recent years, carbon nanotube (CNT) and metal oxide-based supercapacitor (SC) electrodes have shown remarkable enhancements in their electrochemical properties. In this study, we synthesized a NiO and NiO/3%f-CNT nanocomposite through the direct chemical co-precipitation method. The structural and morphological characteristics of the composite were analyzed using X-ray diffraction, scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscope, and energy-dispersive X-ray spectroscope. Additionally, we evaluated the electrochemical performance through cyclic voltammetry, galvanostatic charge–discharge, and electrical impedance spectroscopy. The NiO/3%f-CNT composite electrode revealed a specific capacitance of 390.74 F/g at 5 mV Na2SO4 aqueous electrolyte. Furthermore, even after 5000 cycles, the NiO/3%f-CNT composite electrode displayed exceptional cyclic stability of 93.5% at 1 A/g, indicating its potential for long-term usage. Overall, our results demonstrated that the chemical co-precipitation synthesized nanocomposite possesses superior electrochemical properties, making it a promising candidate for supercapacitor electrode material. [ABSTRACT FROM AUTHOR]

A struvite/kappa-carrageenan composite is synthesized from an aqueous solution of a polysaccharide and inorganic precursors. The phase and elemental composition, as well as the sizes of composite particles in an aqueous colloidal solution are studied by X-ray phase analysis, X-ray energy dispersive analysis, and dynamic light scattering. It is shown that this promising prebiotic composite is capable of producing diffusion-mobile aqueous colloidal solutions with varying degrees of association of the structural elements, which is convenient for use in biomedicine. [ABSTRACT FROM AUTHOR]

High entropy alloys, especially AlCoCrFeNi, have received much attention in recent years due to their unique properties. Therefore, the study of the various properties of this alloy has been the subject of recent fundamental research. In this study, the electrochemical behavior of zirconia-reinforced AlCoCrFeNi high entropy alloy has been investigated. For this purpose, the OCP and Tafel tests on the samples of AlCoCrFeNi-x wt% ZrO2 (x = 0, 5, 10) were performed in a 3.5 wt% NaCl solution. The SEM images were obtained from the corrosion products. Subsequently, the samples were soaked in the above solution for 24, 48, and 72 h, followed by an impedance test. The results of the Tafel test and the SEM images show that the addition of zirconia up to 5 wt% and 10 wt% to the mentioned alloy decreases and increases the corrosion resistance, respectively. The increase in the FCC phase in AlCoCrFeNi-5 wt% ZrO2 decreased the corrosion resistance. The improvement in corrosion resistance in AlCoCrFeNi-10 wt% ZrO2 zirconia is due to the increase in the ceramic phase and the consistency between the passive layers. The EIS test showed that the addition of zirconia to the AlCoCrFeNi system delays the formation of passive layers by up to 72 h, as it leads to the formation of a rough surface. [ABSTRACT FROM AUTHOR]

In this study, in situ titanium diboride particles were synthesized using boron oxide and titanium oxide to reinforce Al 5083 alloy. Stir casting was used to fabricate this composite. The reinforcement particles were formed in situ inside the melt. The working temperature selected for melting and casting was 80 °C. The effect of cerium oxide, cerium oxide + cryolite, and cerium oxide + cryolite + zirconium additives on the composite was investigated. The results showed that cerium oxide decreased the agglomeration of reinforcing particles in the melt. Cryolite prevented melt oxidation, increased melt flow, and improved the distribution of reinforcing particles in the composite. Zirconium caused the refinement of the structure, decreased the agglomeration of TiB2 particles, and increased the tensile strength of the composite. In addition, the dominant fracture mode in samples modified by cryolite + Zr. CeO2 + cryolite + Zr caused ductile fracture, while in samples modified by CeO2 and CeO2 + cryolite, the brittle fracture was ruling. [ABSTRACT FROM AUTHOR]

The automotive and aerospace industries are replacing monolithic conventional materials with composite materials for making variety of components. The aluminum metal matrix composites (AMCs) are a lightweight high perforce materials. The aluminum matrix composites (AMCs) have high strength to weight ratio as well as high corrosion resistance properties. Many automobile and aerospace components are made of AMCs. The stir casting fabrication technique is mostly used by researchers for the fabrication of aluminum matrix composites. In this research, Al 6063 matrix composites were fabricated by reinforcing varying percentages of TiB2 through the stir casting process. The wt% of TiB2 varied from 1 to 3% in Al 6063. The mechanical behavior of developed composites was analyzed. The result showed that tensile strength, hardness, and impact strength of composites were enhanced by 55.51%, 63.98%, and 28.13% respectively in comparison with the matrix material. [ABSTRACT FROM AUTHOR]

The present work investigates the tribological properties and microstructures of tungsten carbide (WC: 0–30 wt%) and few-layer graphene (FLG: 0.1–0.5 wt%)-reinforced aluminum matrix composites fabricated via the powder metallurgy route. The tribological and mechanical behavior of the produced samples were investigated by the pin-on-disk wear testing machine, micro-Vickers hardness test unit, and compressive test machine. Based on the test results, Al-30 wt%WC-0.3 wt% FLG composite exhibited maximum density (3.35 ± 0.01 g/cm3), hardness (98 ± 1.5 HV), compressive strength (189 ± 4 MPa), and lowest mass loss (0.9 mg), wear rate (1.1 × 10–4 mm3/(Nm)), coefficient of friction (0.14). Compared to pure aluminum, the hardness, compressive strength, wear rate, and friction coefficient of Al-30%WC-0.3%FLG was improved by ~ 250%, ~ 77%, 428%, and ~ 77%, respectively. After 0.3 wt% FLG content, the tribological and mechanical properties were decreased due to the agglomerated graphene nanoplatelets from the scanning electron microscope image of the Al-30%WC-0.5%FLG composite. [ABSTRACT FROM AUTHOR]