Increasing Weight Fraction Research Articles

Enhanced Structural, Optical Properties and Antibacterial Activity of PEO/CMC Doped TiO2 NPs for Food Packaging Applications.

In this article, the synthesis, optical, and electrical properties of composites consisting of polyethylene oxide (PEO), carboxymethyl cellulose (CMC), and titanium dioxide nanoparticles are examined. Flexible nanocomposite samples comprising PEO, CMC, and TiO2 nanoparticles were produced swiftly via using the cast synthesis method. In addition, XRD and FT-IR analysis were performed in order to analyze the structures of the prepared samples. Our results demonstrate the PEO/CMC blend's effectiveness in interacting with TiO2 nanoparticles. The optical properties of the PEO/CMC and nanocomposite samples, such as the energy band gap, were studied using the UV/Vis optical absorbance. It was found that as TiO2 NP weight fraction increases, the energy gap narrows. Moreover, TiO2 nanoparticles with an average size of 16 nm were formed in spherical and rod shapes, according to a TEM image. The SEM images demonstrate how the distribution of TiO2 NPs increased upon the surfaces of the prepared films. The antibacterial activity in the nanocomposites was shown to be enhanced by the TiO2 NP concentrations. Finally, we proposed that PEO/CMC-0.8 wt. % TiO2 nanocomposites with enhanced optical, electrical, and dielectric properties should be used in electrochemical devices.

Fabrication and characterization of aluminum-based powders multi-reinforced with nano- and microparticles

Multi-reinforced powders were obtained by high-energy ball milling in a planetary mill. The process of obtaining heterogeneous powders consisted of two stages. At the first stage, a nanocomposite powder of AlMg6 + 0.3 wt.% C60 was obtained. In the second stage, 10, 30, 50, and 70 wt.% Al2O3 were added to the obtained nanocomposite powder and processing continued. Methods such as scanning electron microscopy, X-ray diffraction, and particle size analysis were used to characterize the obtained powders. It is shown that after the first stage of processing, the particles of the composite powder are characterized by an irregular shape. C60 reinforcing particles in the form of nanosized agglomerates were fixed on the surface of aluminum powder particles. After the second stage of processing, the particle size of the powder mixture decreased from 17.8 to 12.3 μm, while the proportion of Al2O3 particles increased from 10% to 70% by weight. It is shown that the synthesized heterogeneous powders were a mechanical mixture consisting of complex composition agglomerates and micro-sized ceramic particles. Complex composition agglomerates were formed from nanocrystalline matrix material particles and C60, and also with Al2O3 microparticles embedded in them, as well as located on the surface. The concentration of Al2O3 particles on the surface and inside the agglomerates increased with increasing weight fraction of ceramic particles in the mixture. It has been found that the introduction of 10-70 wt. % Al2O3 into the powder mixture increases the microhardness of the powder particles by approximately 16-23%. The resulting multi-reinforced powder mixtures can be utilized for coating deposition using the cold gas dynamic spraying method.

In-plane shear and tensile behavior of two-pass injection-molded glass fiber reinforced polypropylene composites with different fiber lengths

Glass fiber reinforced polypropylene (GF-PP) composites have proven a great potential in the designation and manufacturing of control arms, leaf springs, barriers, beams and bridge decks. Two-pass injection molding of GF-PP was investigated in this study. Polypropylene (PP) was injected with different weight fractions (w%) of chopped glass fibers (GFs) with different fiber feedstock lengths (FFSLs). The composites were then crushed and re-injected once again. Some specimens were burned out to check the actual weight fractions and fiber lengths after the injection processes. The fiber lengths dramatically decreased due to damages during two-pass injection processes and crushing. The manufactured specimens were tested in tension, and the results indicated that the tensile strength increased slightly at w = 10% of GF. Further increase of GF weight fraction leads to a drop in the tensile strength below neat PP. The results of SEM micrographs showed an increase in air voids concentrations at high GF percentages which clarifies the reason behind the drop in the tensile strength. Also, in-plane shear tests were carried out using the Iosipescu fixture where a slight increase in the in-plane shear strength was noticed by increasing fiber weight fractions. In-plane shear moduli of all specimens were measured experimentally by strain gauges and calculated theoretically. The shear modulus was enhanced by glass fiber addition and a further increase was noticed by increasing the fiber weight fractions.

Experimental Study on the Influence of Moisture and Clay Content on Stress Wave Attenuation Characteristics of Filled Joints

Artificial filled joints made of sand–clay mixtures with different clay weight fractions and saturations have different wave attenuation capacities. In this paper, the high amplitude impact test of sand–clay mixtures was carried out by using split Hopkinson pressure bar (SHPB) equipment. The results showed that with the increase of clay weight fraction, the particle crushing decreased continuously, while the wave attenuation coefficient decreased first and then increased. When the weight fraction of clay was 50%, the wave attenuation coefficient reached the minimum among the tested working conditions, and the ratio of transmitted energy to incident energy reached the maximum. With the increase of saturation, the particle crushing decreased first and then increased, while the wave attenuation coefficient increased first and then decreased. When the saturation was 25%, the wave attenuation coefficient reached the maximum, and the proportion of transmitted energy to incident energy reached the minimum. Because of the lubrication of water reduced the friction between particle, the specimen more prone to deformation and particle crushing reduced. As the saturation increased, this effect gradually decreased. In the case of the wave absorbing layer of protective works, special attention should be paid to the adverse effects caused by groundwater.

The influence of sustainable reinforcing particulates on the density, hardness and corrosion resistance of AA 6063 matrix composites

The need for the fabrication of sustainable aluminium matrix composites (AMCs) is being sought after as practical alternatives to conventional metals and their alloys. This study was undertaken to investigate the effect of sustainable materials on the mechanical, physical and corrosion resistant properties of AA 6063. The weight fraction of the hybrid reinforcements was varied at 2.5, 5.0, 7.5 and 10.0 wt.%. For each variation, the fly ash and eggshells were weighed equally. The fabrication route selected was stir casting. The analysis of the density showed that the property decreased with increasing weight fraction of the hybrid reinforcements. Evaluation of the microhardness revealed hardness values of 78.13, 81.19, 81.54, 82.14, and 86.71 HV for the base metal, 2.5, 5.0, 7.5 and 10.0 wt.% samples respectively. The corrosion resistant properties were studied in 3.5 wt.% NaCl medium. The investigation showed that the reinforced AMCs exhibited improved corrosion resistance compared to the base metal. However, the 7.5 wt.% sample exhibited the least corrosion rate of 8.649 X 10-5 g/h.

Study of Mechanical Properties on Ferric Oxide Microparticles Reinforced with Polyethylene

Polyethylene and ferric oxide microparticles were mixed in this work to generate a new polymer composite. Weight fraction and microparticle size were studied experimentally to discover how they influenced the tensile strength and Young’s modulus. A response surface methodology was employed in the design of the research. The increased weight fraction of reinforcement results in the increase in Young’s modulus and lowers the elongation percentage. As the microparticles expanded in size, so did their effect on the composite’s mechanical characteristics. The tensile strength of specimens containing 20% ferric oxide and particle size of more than 91 µm was dropped by 18 percent due to the agglomeration of microparticles. The addition of 24% Fe2O3 microparticles smaller than 33 μm raised Young’s modulus and tensile strength by 340 percent and 65 percent, respectively.

Enhancement the Properties of Local Crude Oil using DE-asphalting Process

Asphaltene precipitation is one of the main hitches in the oil sector through the production and refining stages that causes real damages every year. The object of the present work is to study the effect of the deasphalting process of crude oils using different concentrations (5, 10, and 15 wt.%) of n-heptane as a solvent, the experiments were done at a laboratory scale. The deasphalting process quality was based on the sulfur content, conradson carbon residue, density, API, and kinematic viscosity. The results have been shown that the deasphalting process quality was enhanced with increasing weight fraction of added n-heptane, the API value and kinematic viscosity were increased by about 37 and 19.5% respectively, while the density, conradson carbon residue, and sulfur content were decreased by about 5, 17 and 26.8% respectively when 15 wt.% of n-heptane was used, i.e. , the quality of deasphalting methods was enhanced with increased solvent concentrations.

Theoretical and experimental validation of thermal and heat transfer performance of novel ethylene glycol - Cr2AlC nanofluids

Synthesizing stable nanofluids with favourable thermal properties that can cater to practical applications is a challenge over the past few years. This paper presents the preparation and analyzes the thermal efficiency of the novel nanofluid prepared by the suspension of nanocrystalline Cr2AlC MAX phase powder in ethylene glycol (EG). Incorporation of h-BN, MoS2, Al2O3, and Cr2AlC showed a thermal conductivity enhancement at 303 K when compared to EG. Accurate experimental models for the thermal conductivity and the viscosity of EG + Cr2AlC nanofluids are estimated. The theoretical analysis of the flow profiles of EG + Cr2AlC/Al2O3/MoS2/h-BN nanofluids is carried out with Blasius and Sakiadis flow models. The Cr2AlC MAX phase possesses both ceramic and metal properties that help these nanofluids to show high heat transfer performance. The results show that 0.50 wt% EG + Cr2AlC nanofluid displays maximum improvement in heat transfer performance. There is a substantial rise in the thermal conductivity when both temperature and weight fraction increase. The simulated flow of the nanofluid past a plate indicated superior heat transfer and thermal profiles for the EG + Cr2AlC nanofluids. For the flow past a moving plate, the nanofluid possesses less skin friction at the plate, which is favourable for various practical applications.

Synthesis and properties of Poly(vinyl alcohol) hydrogels with high strength and toughness

PVA hydrogels with high strength and toughness are fabricated by dual physical and chemical cross-linking. The best comprehensive mechanical properties can be achieved by reaction at room temperature followed with freeze-thaw and annealing treatment. Besides, the mechanical properties of PVA hydrogel increased first and then decreased with the increase of molecular weight or mass fraction. By changing the reaction solvent, the mechanical properties of PVA hydrogel could also be effectively adjusted. Therefore, the influences of various factors on the mechanical properties of PVA hydrogel can be obtained.

Microstructure and particle size effects on selected mechanical properties of waste glass-reinforced aluminium matrix composites

The development of new lightweight engineering materials with highly improved mechanical properties has been a thought-provoking issue of materials engineering lately. The attempt being made by the industrial and academic bodies has engendered the shift to composite materials over conventional ones. Aluminium reinforced composites are now being used in the transportation industries such as automobile and aerospace. Waste glass is a hard ceramic material which is majorly made up of silica, it is cheap, available and can serve as a replacement for costly reinforcement like silica, silicon carbide and titanium carbide. As a result, this research studied the effect of stir casting parameters (weight fraction of reinforcement and particle size) on the physical and mechanical properties of aluminium Al 6061/waste glass composites. The results obtained showed that density and fracture toughness of the samples reduced with an increase in weight fraction and particle size of waste glass. Brinell hardness improved progressively with increase in the weight fraction of waste glass and a reduction in particle size. Tensile strength improved from 0 to 8 wt% after which a reduction was noted at 10 wt% for samples reinforced with −6 µm particle size while 6 wt% reinforcement had the best tensile strength for samples reinforced with −13 µm and –23 µm particles sizes. The morphology examined showed the interfacial interaction between matrix and reinforcement in relation to mechanical properties. The study established the effectiveness of the composites as compared to the pure matrix which made them better candidate materials for various engineering applications like automobiles.

Mechanical property analysis of glass particulates reinforced Aluminum matrix composites

Technological advances involve materials with unique qualities that cannot be provided by ordinary metal alloys, ceramics, or polymeric materials. In the present work, an attempt is made to prepare glass particulates reinforced Aluminum Matrix Composites (AMCs). The composite was prepared using a stir casting process with 0 to 12 wt% glass particulates reinforcement with a particle size of 75 µm. The ASTM standard was used to test mechanical properties such as hardness and tensile strength. The results revealed that the Vickers hardness improved with an increase in weight fractions of glass particulates. The tensile strength increases up to 8 wt% of reinforcement, then decreases up to 12 wt% of reinforcement. The porosity level depicted an increasing trend as the volume percentage of reinforcement increase. The microstructure observation implies that the glass particulates were fairly distributed in 8 wt% and 12 wt% while reinforcement particles' clustering was observed in 4 wt% reinforced composites.

Evaluation of the influence of alumina nano-particle size and weight composition on the corrosion resistance of monolithic AA1070 aluminium

Corrosion resistance of AA1070 aluminium alloy (AA1070) was compared to AA1070 reinforced with alumina at weight composition (wt. %) of 5% and 10%, and grain size of 150 nm and 600 nm. Potentiodynamic polarization and open circuit potential analysis were employed in 0.0125 M H2SO4, 3.5% NaCl and 0.0125 M H2SO4-3.5% NaCl solutions. Data showed 0.0125 M H2SO4-3.5% NaCl solution was the most deleterious with peak corrosion rate value of 6.682 mm/y while 3.5% NaCl solution was the weakest with peak value of 0.084 mm/y. AA1070 at 5% (wt. %) and 150 nm particle size generally displayed the highest corrosion rate with values between 0.084 and 6.682 mm/y. However, visible decrease in corrosion rate occurred with increase in alumina weight fraction and particle size due to growth of the protective oxide on the composite and reduction of discontinuities to minimal values between 0.031 and 2.192 mm/y at 10% alumina weight fraction and 600 nm particle size. Cathodic and anodic reaction mechanisms significantly differs with respect to the electrolyte. Anodic reaction mechanism appeared under activation control in the sulphate-chloride and chloride solution, compared to cathodic reaction mechanism in the sulphate and sulphate-chloride solutions. Significant anodic degradation reaction was prevalent on the anodic polarization plot in the sulphate solution. Plots from open circuit potential analysis shows the composites and monolithic Al were the most thermodynamically stable in H2SO4 solution. In the sulphate-chloride solution, significant potential transients coupled with high corrosion tendency are conspicuous. The plot showed chaotic thermodynamic behaviour active passive transition behaviour of the passive film.

RETRACTED: Physical, mechanical and dry sliding wear properties of non-woven viscose fabric epoxy-based polymer composites: An optimization study

Polymer-based composites have been widely used in the enhanced tribological technologies of various automobile, aerospace industry, sports, etc. The epoxy-based polymer composites reinforced with glass fiber have significantly improved the wear inhibitors and ultimate strength along with ultra-low density than other available materials. This current research aims to fabricate a variation of such non-woven viscose-based polymer composites for various weight fractions (100–400 GSM) with a constant fiber loading of 30 wt% and subsequently analyze its physical, mechanical, and tribological properties under various operating parameters. The density of the fabricated composite exhibits an increase of magnitude with an increase in weight fraction. The composites consist of 400 GSM fabric showing a higher tensile, impact, flexural strength, hardness, and inter lamina shear strength (ILSS). A pin-on-disc wear set-up held dry sliding wear tests of various nonwoven viscose fabric-based composites under various operating parameters like sliding velocity, sliding distance, area density, and normal load. A Taguchi-based L16 orthogonal array design was utilized to estimate the optimal behavior for maximum wear resistance for operating conditions. The result reveals that the normal load over the composite contributes the highest towards wear on a composite compared to area density, sliding velocity, and distance. The wear phenomena have been verified with SEM micrographs to characterize various wear phenomena like fiber rapture, ploughing, micro-cracks, and wear lines.

The effect of artificial aging on the impact behavior of SiC nanoparticle‐glass fiber‐reinforced polymer matrix composites

AbstractThe low‐velocity impact behavior of SiC nanoparticle‐glass fiber‐reinforced polymer matrix composites (PMC) in terms of different weight fraction of nanoparticle, artificial aging time, and impact energy was investigated in this article. In this context, silicon carbide (SiC‐70 nm) ceramic nanoparticle in weight fractions of 0%, 0.1%, 1%, 2%, 3% filled glass fiber‐reinforced PMCs were produced by vacuum infusion technique. The specimens were artificially aged in 0, 750, and 1500 h, 85% relative humidity and 70°C in air conditioning cabinet. The after‐impact damage regions were obtained using ultrasonic scanning technique for three different impact energies of 10, 20, and 30 J. The weight of specimens was measured at certain periods during aging and the weight change was examined. As the weight fraction and aging time were increased, the impact resistance of specimens decreased. At the beginning of aging period, the weight of specimens increased; however, the increase in weight decreased over time. Ultrasonic scanning results showed that the damage geometry changed and increasing discontinuity with increasing weight fraction and artificial aging time.

Soft/hard ferrite nanocomposites: Evaluation of temperature dependent dielectric properties

Nanocomposites of cobalt ferrite (CoFe2O4) and strontium ferrite (SrFe12O19) were synthesized with various weight ratios 1:1, 1:2, 1:4, 1:8 and 1:16, by chemical co-precipitation route with higher content corresponding to SrFe12O19. Dual phase refinement employed for the prepared composites and confirms the presence of independent CoFe2O4 and SrFe12O19 phases. The increasing weight fraction of SrFe12O19 in the prepared composites is in accordance with its increasing weight ratio. An increase in compressive strain in the composites was attributed to larger ionic radius of Sr+2 ions. The electrical behavior in the composites was described by Cole-Cole plots at 250 °C from 20 Hz-106 Hz. An increase in impedance with increasing weight ratio of SrFe12O19 was observed, due to creation of effective scattering centers. Conductivity mechanism was explained by Overlapping large polaron tunneling (OLPT) model. A decrease in dielectric constant with increasing frequency is due to decreasing space charge polarization, due to inability of charge carriers to follow the varying ac field. Decreasing trend in dielectric loss for the prepared composites confirms their utility in microwave absorption applications.

Lateral-torsional buckling of functionally graded porous arches with graphene platelets reinforcements under an arbitrary radial concentrated load

This paper investigates the lateral-torsional buckling of functionally graded porous (FGP) circular arches with an I-section made of graphene platelets reinforced composites (GPLRC) under an arbitrary radial concentrated load, which has not been reported in open literature so far. The effective elastic modulus of the FGP- GPLRC arches is estimated by the Halpin-Tsai micromechanics model. After pre-buckling internal forces caused by the concentrated load have been obtained, the principle of stationary potential energy and Rayleigh-Ritz method are employed to derive theoretical solutions for the lateral-torsional buckling loads of FGP-GPLRC arches based on Timoshenko beam theory. The present theoretical solutions for the buckling loads are validated against the finite element results. The analytical expression of the effective warping stiffness and torsional stiffness of FGP-GPLRC arches are then obtained by an integral method. Finally, the influences of pore distribution pattern, porosity coefficient, weight fraction of graphene platelets (GPLs), load position, include angle and slenderness ratio of the arch on the lateral-torsional buckling load are analyzed in detail. Results show that a higher porosity coefficient leads to lower buckling loads but an increase in GPL weight fraction can effectively enhance the buckling resistance of the arch. Compared with their counterparts with uniform or asymmetric porosity distribution, FGP-GPLRC arches with symmetric non-uniform porosity distribution have higher lateral-torsional buckling loads.

Evaluation on Mechanical Properties of Coated RHA-TIO2-LM24 Aluminium Alloy Composite

Abstract: In the present research work, liquid state technique is employed to prepare the LM4/RHA/TiO2 composites containing four different mass proportion of RHA and TiO2. The weight proportion of reinforcements ie RHA-1,3&5 and TiO2 2,5&6 respectively. Hybrid composite with 3% of RHA and 6% of TiO2 showed the maximum Tensile strength of 298.37 N/mm².It is found that there is 37 % increase of tensile strength while addition of RHA and TiO2 to LM 24.The aluminium based particulate reinforced composite, the dislocations are generated during solutionizing due to thermal mismatch between the matrix and the ceramic reinforcement particles. It can be inferred that the tensile strength increased with an increase in the weight percentage of rice husk ash and TiO2. Because, the RHA particles act as barriers to the dislocations when taking up the load applied. It has been observed that with changing rate of TiO2 compressive quality increments from 478.83 to 653.79 MPa. The increase in compressive strength is mainly due to the decrease in the inter-particle spacing between the particulates since RHA and TiO2 are much harder than LM24. The presence of RHA and TiO2 resists deforming stresses and thus enhancing the compressive strength of the composite material. The maximum hardness value obtained for 5 wt.% of RHA and 6 wt.% of TiO2 .ie.117 BHN. It was observed that the hardness of the composite linearly increasing with the increase in weight fraction of the rice husk ash particles. This occurs due to increases in surface area of the matrix and thus the grain sizes are reduced. The presence of such hard surface area offers more resistance to plastic deformation which leads to increase hardness.. Keywords: LM4/RHA/TiO2, Tensile testing, Compression, Hardness, Rice husk.

Low-loss NiZnCo ferrite composites with tunable magneto-dielectric performances for high-frequency applications

A series of Ni0.5Zn0.3Co0.2Fe2O4/epoxy magnetodielectric composites were synthesized through solvent-assisted method and demonstrate tunable permeability and permittivity, ultralow losses and high refractive index over a broad frequency region of the VHF and UHF bands. Experimental results reveal that the permeability μ' decreases from ~4.2 to ~3.5 while the permittivity ε' was improved from ~5.0 to ~6.1 with an increase in epoxy weight fraction from 1 to 20 wt%. These variations are shown to be intimately related to the microstructures in accordance with effective medium theory and magnetic circuit model. Correspondingly, the characteristic impedance of the magnetodielectric composite medium is varied from ~0.75 to ~0.90 while maintaining a refractive index around 4.5. Typical magnetic loss as tan δμ and dielectric loss as tan δε at 0.5 GHz are as low as in the order of 10−2 and 10−3, respectively. These magnetodielectric materials provide excellent radio frequency results that allowing for the realization of the high-performance miniaturized electronic devices, systems, and platforms.

Mechanical Properties, Tribology and Electrochemical Studies of Al/Fly Ash/Eggshell Aluminium Matrix Composite

This work was carried out to investigate the effect of carbonized eggshells (CES) and fly ash on the microstructure, mechanical properties, wear, and corrosion characteristics of Al-Si12. The weight fraction (wt.%) of the CES particles was kept constant at 2.5 wt.%, while that of fly ash was varied at 2.5 wt.%, 5.0 wt.%, 7.5 wt.%, and 10.0 wt.%. The selected fabrication route was stir casting. The x-ray diffraction (XRD) analysis of the cast aluminum matrix composites (AMCs) revealed the presence of phases including α-aluminum, SiO2, and Si with the formation of the intermetallic CuAl2 phase. The microhardness of the cast samples increased with increasing weight fraction of the reinforcements up to the 7.5 wt.% fly ash sample. The tensile strength and compressive strength were highest for the 2.5 wt.%/CES 2.5 wt.%. Tribology studies showed that the lowest wear rate of 4.91 × 10-5 mm3/Nmm was obtained for the 2.5 wt.% fly ash sample, while the corrosion studies showed that the corrosion rate of 2.70 × 10-5 g/hr was lowest for the 2.5 wt.% fly ash as well.

JUTE AND COTTON COMPOSITES REINFORCED UNSATURATED POLYESTER

In this study, the effect of adding two different types of reinforcing natural fibers (jute and cotton) singly and in combination as a hybrid to unsaturated polyester resin was investigated. At the first discontinuous random fibers used in (5)mm length are added separately with different weight fraction as (3, 4.5, 6, and 7.5 wt.%) for both types fibers, then these fibers were mixed at (3.75 wt.% jute, 3.75 wt.% cotton) in (5)mm long. and The mechanical tests (hardness, Impact, and compression), as well as moisture absorption, are performed. The results show an increase in these properties with increasing weight fraction of fibers (jute & cotton) and reach the maximum amount at the addition of weight fraction of (7.5 wt.%) of both fibers (jute and cotton) separately. All composite specimens reinforced with jute fibers showed the highest hardness, Impact, compression, and moisture absorption among the composite specimen reinforced by cotton fibers and higher than in combination as a hybrid it was (93.1, 28.81 KJ/m2, 205 Mpa., and 1.4%) respectively.