Composition Weight Ratio Research Articles

Grain size effects on the behavior of silicone rubber high voltage power cables using seagull optimization algorithm

<p>High voltage insulation is one of the most important components of electrical power systems. Polymeric materials have lately supplanted ceramic materials as insulating materials due to their low weight, straightforward structure, high mechanical strength, good performance in the presence of pollution, ease of transportation, and ability to enhance voltage. The purpose of this thesis is to add micro and nano-sized aluminum oxide (Al2O3) fillers to silicone rubber (SIR) to enhance its electrical characteristics. Micro Al2O3filler with contents of 10wt%, 20wt%, 30wt%, and 40wt% was combined with nano Al2O3with contents of 1wt%, 3wt%, 5wt%, and 7wt% to create samples of SIRcomposites. The composites’dielectric strength is evaluated in a variety of environments, including dry, wet, low-salt wet, and high-salt wet circumstances. In order to boost the insulator’s dielectric strength under diverse environmental conditions, this research aims to develop a weight ratio composition for such a composite. The ideal concentration of nano or micro Al2O3fillers has been calculated using the whale optimization algorithm (WOA) and seagull optimization algorithm (SOA).</p>

Investigation on various properties of Dy0.7Ca0.3MnO3:TiO2 based nano-micro composites

In the present research work, manganite metal oxide nano-micro composites have been synthesized successfully wherein, chemically grown Dy0.7Ca0.3MnO3 was combined in different weight ratio composition of micron sized TiO2 (i.e., 0 %, 10 %, 20 %, 30 %, 40 % and 100 %). Prepared nano-micro DCMO:TiO2 has been characterized further wherein, structural aspects have been carried out using X-ray diffraction and W-H plot measurements which provides information regarding crystalline size, lattice strain and crystallinity. FESEM and HRTEM has been characterized for the assessment of the crystallinity and granular morphology. The elemental composition with desired stoichiometric quantities has been verified using EDAX. SAED patterns gives detailed information about intereticular distance and angles between crystallographic planes. Different frequency dependent electrical properties (i.e., dielectric constant (ε’), a.c. conductivity (σac) and impedance (Z)) carried out in the frequency range of 20 Hz to 2 MHz. The observed modified electrical properties have been understood using different theoretical models, mechanisms and different aspects (role of grain and crystalline size). Temperature dependent magnetization (M-T) measurements have been carried out to evaluate the magnetic phase shifting of the sample which has been understood using ZFC and FCC protocols. These phase shifting has been verified using M-H loop at different temperatures of 5 K and 300 K. The adaptation in magnetic properties have been discussed using different magnetic aspects.

Theoretical analysis on flexural strengthening of RC beams using GFRP composites in terms of strength to the weight ratio: A way forward

Aramid, Glass or Carbon Fibre Reinforced Polymer (GFRP/CFRP) are three types of composites that are commonly used in the civil, mechanical and automobile sectors worldwide. GFRP composites are often used for structural member strengthening, repairs, and rehabilitation. In comparison to CFRP and Aramid FRP composites, GFRP is easily available, inexpensive, good strength to the weight ratio, and has several additional benefits. The strength-to-weight ratio of GFRP composites and steel plates for flexural strengthening of RC beams is investigated in this work. Theoretical analysis for the RC beam strengthened with GFRP composites and steel plates were performed using the established equation based on Indian standards and the ACI code. The self-weight of the beam and the superimposed dead load owing to the block/brick work were taken into account in the design calculations. The beam's load carrying capability is inadequate due to the excessive load, thus it must be strengthened with different materials: GFRP Chopped Strand Mat (CSM) composites or steel plates. The evaluations were conducted under the assumptions that the loss of moment carrying capacity due to concrete deformation caused by bolt holes and failure due to GFRP composite delamination would be disregarded. Strength to weight ratio of GFRP composites and steel plate requirements have been computed and compared for the known dimensions, unit weight and tensile strength of the strengthening materials, and load carrying capability of the strengthened RC beam. Comparative study proves that the flexural strengthening of RC beams using GFRP composites, the strength to weight ratio is much higher than when the identical beams are strengthened with steel plate.

Investigating the impact resistance of E-glass/ Polyester composite materials in variable fiber-to-matrix weight ratio composition

E-glass/polyester composite is formed by combining E-glass fiber as reinforcement with a polyester resin matrix. These constitute materials have different properties from the composite they built. The fiber mat with 65, 55, and 35 weight percentages and a matrix with weight percentages 35, 45, and 65 have been prepared. In each composition reinforcement, the test samples are modeled using Ansys ACP—pre and fabricated using the hand-layup technique. By setting three test samples for each class of composition, a total of nine test samples are prepared. Impact tests are conducted on each test sample using an Izod impact testing machine and using Ansys explicit dynamics numerically. The maximum mechanical properties are obtained in 65 by 35 fiber-to-matrix ratios of the composite experimentally and numerically when compared with the other stated composition. Results of the numerical analysis show that good mechanical properties can be achieved using balanced and compatible reinforcement with the matrix in the composite.

Utilization of Sandblasting Waste as an Alternative Material for Paving Blocks

Sandblasting is an activity of cleaning industrial equipment made of metal using quartz sand. Every day the amount of waste produced is getting bigger so it needs to be processed to reduce its surface area. One way that can be used to process sandblasting waste is solidification into building material products. This study uses sandblasting waste as a substitute for fine aggregate in the manufacture of paving blocks. Paving block production was carried out using three research variables, namely the weight ratio of cement and waste, cement water factor (FAS), and maximum grain size. Comparison of the weight of cement and waste using composition of 1:3, 1:4, and 1:5. The cement water factor used was 0.35, 0.425, and 0.5. While the grain sizes that were filtered were 1.2 mm, 2.4 mm, and 4.75 mm. The results showed that of the 27 variations of the mixture produced, the samples with sample code V5 (composition 1:3, FAS 0.425, and grain size 2.4 mm) produced the highest compressive strength, namely 25 MPa with quality B. ANOVA analysis was performed to determine the effect of the three variables on compressive strength and it was found that the weight ratio composition of cement and waste was the most influential. The TCLP test was carried out to determine the potential for leaching of heavy metals Cr6+, Cu, Pb, and Zn, which then resulted in the content of the four substances being below the quality standard of Government Regulation Number 22 of 2021

Mechanical Properties of Banyan Fiber‐Reinforced Sawdust Nanofiller Particulate Hybrid Polymer Composite

The utilization of renewable raw materials, such as natural fiber composites, can be prioritized in the building industry as it transitions to a bioeconomy. The sustainable product can improve environmental protection; therefore, the present work is stated with the natural fibers of chopped banyan fiber reinforced with sawdust nanocellulose epoxy‐based composite fabricated by hand layup process. To identify the mechanical effects of tensile strength, flexural strength, impact strength, and hardness value for five different weight ratios of chopped banyan fibers and sawdust nanofiller materials, the composite weight ratio was made with 60% of matrix phase that was fixed for all five samples and 40% of reinforcement phase in which the fibers and filler percentage can vary for five samples. The results are revealed sample E (50 g of banyan, 25 g of saw dust, 110 g of epoxy, and 185 g of laminate) given a more tensile strength of 39 MPa and a flexural strength of 34 MPa, and sample A was given a high impact energy absorption capacity of 18 Joule compared with other samples of hybrid composite; and also, the SEM morphological was used to identify the surface interaction and failure mode of this composite laminates.

Development of sustainable microwave-based approach to recover glass fibers for wind turbine blades composite waste

In this study, we report the development of a sustainable microwave-assisted chemical recycling process to recycle glass fiber reinforced polymer (GFRP) composite waste. Degradation of GFRP composites using hydrogen peroxide and acetic acid with microwave irradiation was investigated. Process parameters: Chemical solvent to composite weight ratio (mL/g) and microwave exposure duration were used at constant microwave power (700 W). The chemical solvent ratio (oxidizing agent/acid:30/70, 50/50) with microwave exposure of 180 s could achieve nearly complete degradation of epoxy. The decomposition rate (Dy) of epoxy was found as 97.2%. TGA and FTIR analysis was done to determine Dy and basic chemical structure of recovered glass fibers (RGFs), respectively. SEM analysis was done for surface morphology of virgin glass fibers (VGFs) and RGFs. The RGFs showed 99.8% ultimate tensile strength, 93.3% Young's modulus, and 95.7% strain-to-failure compared to VGFs. A plausible mechanism for the degradation of matrix material has been proposed.

RELAXATION FREQUENCY SHIFT IN TRIGLYCINE SULFATE UNDER THE INFLUENCE OF SILICA NANOPARTICLES AT LOW FREQUENCIES

The present work is devoted to clarifying the influence of silica nanoparticles on dielectric relaxation frequencies of a classical ferroelectric – triglycine sulfate at low frequencies (102 – 107 Hz) from 20 ˚C to phase transition point for composite samples prepared at different composition weight ratios. Theresults indicated the reduction of relaxation frequency with increasing the silica content due to the intensified interaction between nanoparticles and tryglycine sulfate inclusion. The nature of this interaction was thoroughly discussed in this study.

Experimental and numerical investigation on the residual distortion and stress fields in un-symmetric hybrid composite laminates induced by the manufacturing process

Due to the high strength to weight ratio of composites, their applications are extending rapidly in many industries. Composites can be fabricated by using different constituent (including fiber and matrix) materials. Different curing cycles and thermal expansion coefficients of matrix and fibers in hybrid composites may lead to residual stresses and distortion. Residual stresses can decrease the durability of the part during commissioning, and distortion makes the assembly process more difficult or even impossible. In this study, different inter-ply hybrid laminates reinforced by carbon and glass fibers are fabricated by hand lay-up method. After curing, they are cooled by three different rates. Distortions of laminates are measured by coordinate measurement machine and their residual strains are measured by the incremental hole drilling method. Calibration factors are calculated by simulation and finally, residual stresses are determined. Also, residual stresses and distortion of laminates are predicted by classical lamination theory and finite element method. The obtained results are compared and acceptable conformity is seen. Comparison of experimental distortion results showed that cooling rates in the laminate which have more degree of un-symmetry will lead to 100 percent deviation of numbers.

Tunable Crystalline Phases in UV-Curable PEG-Grafted Ladder-Structured Silsesquioxane/Polyimide Composites.

A series of UV-curable hybrid composite blends containing a carboxylic acid functionalized polyimidewith varying amounts of high molecular weight (~1 K) PEG-grafted ladder-structured polysilsesquioxanes copolymerized with methacryl groups were fabricated and their structural, thermal, mechanical, and surface properties characterized. At a composite weight ratio of polyimide above 50 wt.%, a stark shift from amorphous to crystalline polyethylene glycol (PEG) phases were observed, accompanied by a drastic increase in both surface moduli and brittleness index. Moreover, fabricated composites were shown to have a wide range water contact angle, 9.8°–73.8°, attesting to the tunable surface properties of these amphiphilic hybrid polymer composites. The enhanced mechanical properties, combined with the utility of tunable surface hydrophilicity allows for the possible use of these hybrid polymer composites to be utilized as photosensitive polyimide negative photoresists for a myriad of semiconductor patterning processes.

Characteristics of Bamboo Particleboard Bonded with Citric Acid-Starch Using Three-Step Press Cycle Method

In an attempt to reduce the use of a formaldehyde-based adhesive that is dangerous for both human health and environment, several studies had been done to develop particleboard with natural bio-based adhesives. Between those bio-based adhesives that have been investigated, the combination of citric acid-starch was potential to be developed further as an adhesive to particleboard. In this research, the effect of starch addition and press temperature on the properties of bamboo particleboard were evaluated. This research uses a combination of citric acid/starch with the composition weight ratio of 100/0, 90/10, 80/20 and 70/30 and press temperature of 160, 180 and 200 °C. The manufacture of particleboard also used a three-step press cycle method which has not been done before in Petung bamboo particleboard production. The result showed that the three-press cycle method used in this research was able to produce a board with excellent properties than board produced by single-step press cycle method. This showed that the manufacture of the board in this research was more efficient to produce citric acid-starch bonded particleboard than previous method being used. The results also showed that both the addition of starch and the increase of press temperature especially improved bamboo particleboard mechanical properties. The board with the optimum properties resulted from particleboard with citric acid/starch adhesive with the composition weight ratio of 80/20 and press temperature of 180 °C which could meet JIS A 5908 (2003) type 18 requirement.

Phase transition and dielectric relaxation of a mixed ferroelectric composite from cellulose nanoparticles and triglycine sulfate

The work is devoted to the study on electrophysical properties of a novel ferroelectric composite consisting of triglycine sulfate (TGS) and cellulose nanoparticles at different composition weight ratios from 25 to 120 °C under a weak electric field at frequencies of 102–106 Hz. The obtained results indicated that an increase in cellulose concentration in the composite led to increasing the phase transition temperature by three to a few tens of degrees Celsius higher than those for single crystal TGS (+49 °C) and led to decreasing characteristic relaxation frequency of TGS inclusion in the studied frequency range.

Effects of composition ratio on structure and phase transition of ferroelectric nanocomposites from silicon dioxide nanoparticles and triglycine sulfate

ABSTRACTThe present work is devoted to study on influences of silicon dioxide nanoparticles (SiO2) on structure and phase transition of a classical ferroelectric of triglycine sulfate (TGS) by synthesizing a composite containing SiO2 and TGS at different composition weight ratios. Particle size analysis, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) techniques were utilized to charaterize the synthesized composite. The experiments for investigation of phase transition were conducted from 20 to 120°C under a weak electric field (1 V.cm−1) at 1 kHz. The results revealed an expansion of ferroelectric phase of TGS by 15–55°C with increasing the SiO2 content. Besides, an additional phase transition point which is characteristic for the bulk clusters of TGS was found at low content of SiO2. The detected anomalies were discussed thoroughly based on the interaction between components in the composite.

Reflection Loss Characteristic as Coating Thickness Function on the Microwave Absorbing Paint at a Frequency of 8-12 GHz

The effect of paint thickness based on Ba0.6Sr0.4Fe10MnTiO19 nanoparticles as a microwave absorber has been investigated. Nanoparticle powder Ba0.6Sr0.4Fe10MnTiO19 was made using a solid-state reaction method milled with seven hundred rpm for fifty hours then characterized first. Qualitative and quantitative analysis of structure and phase was measured by using X-ray diffraction (XRD). The sample has a hexagonal structure with a space group P63/mmc, and no other phase is detected. Meanwhile, scanning electron microscopy (SEM) was used for surface morphology analysis. Homogeneous sample granules with an almost round shape with a nanometer scale between seventy to one hundred nanometers. Loop hysteresis obtained from the measurement of vibrating sample magnetometer has a maximum magnetic value of Ms = 50 emu/g, magnetic remanent (Mr) of 32.0 emu/g and coercivity (Hc) of 0.34 T. Next step the nanoparticles were mixed with paint with a weight ratio composition of 30: 70. The mixture was then sprayed with several variations of paint thickness on the iron metal plate. After that, the reflection loss characteristic was measured by using vector network analyzer on a painted plate and resulted that the best performance of microwaves absorption resulted in the sample with two sprays. It was concluded that the paint thickness could affect the ability of reflection loss, but the thicker the paint does not mean that the loss of reflection is getting better.

Novel synergistic transparent k-Carrageenan/Xanthan gum/Gellan gum hydrogel film: Mechanical, thermal and water barrier properties

The aim is to develop novel synergistic transparent k-Carrageenan/Xanthan gum/Gellan gum (k-C/X/G) hydrogel films with different weight ratio composition and to study the effect of these compositions on the physical properties of the films. The structure and morphological properties of the films were investigated by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). Results for FT-IR, DSC and SEM analysis showed a clear interaction between k-C, X, and G to form a new material. The mechanical, thermal and water barrier properties such as water vapor permeability (WVP), water contact angle (WCA) and moisture content were determined. The temperature at 5% weight loss (T5%) are in the range of 64.2–121.9 °C. The WVP exhibits are in the range of 1.8–2.4, contact angle are in the range of 32–65.8° and moisture content 16.5–21.51. The hydrogel film had good tensile strength of 19.1–31.0 MPa and elongation at break of 13–19% and tensile modulus of 1.6–2.4 GPa. The UV results indicate that the films were very transparent. The range of properties of the ternary k-C/X/G hydrogel films suggest that the presence molecular interaction and cross linking within the blends.

Synthesis and characterization of zinc oxide nanoparticles and activated charcoal based nanocomposite for supercapacitor electrode application

In this study, zinc oxide (ZnO) nanoparticles (NPs) have been synthesized at room temperature by co-precipitation method. It has been used as an electrode material by making composite with activated charcoal (AC) powder for its application in energy storage devices such as a supercapacitor. For synthesis of ZnO nanoparticles, zinc nitrate hexahydrate {Zn(NO3)2} and sodium hydroxide (NaOH) have been used as an initial precursor. The ZnO nanopowder obtained by using co-precipitation has been calcined at 400, 500, and 600 °C for 2 h. The nanoparticles have been characterized using Synchrotron radiation based angle dispersive X-ray diffraction (ADXRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Supercapacitor cells have been fabricated by using of zinc oxide nanoparticles-activated carbon (AC) nanocomposite electrode in different composition (weight ratios) from 1:1 to 1:2. Electrochemical properties of the prepared nanocomposite electrodes and fabricated supercapacitor cells have been characterized using a.c. impedance, cyclic voltammetry (CV) and charge discharge (CD) techniques by using 6 M KOH and 1 M NaOH as an electrolyte. The ZnO–activated carbon nanocomposite electrode with 6 M KOH showed a maximum capacitance of 479.6 mF cm−2, which is equivalent to single electrode specific capacitance of 342.6 F g−1. Similarly, the ZnO–activated carbon nanocomposite electrode with 1 M NaOH showed a maximum capacitance of 456.5 mF cm−2, which is equivalent to single electrode specific capacitance of 326.1 F g−1. The electrochemical behavior of the neat ZnO nanoparticles has also been studied. The specific capacitance of the supercapacitor is stable up to 2000 cycles at 100 mV cm−2, which shows that the device has good life cycle and electrochemical reversibility with 6 M KOH and 1 M NaOH electrolyte.

In-situ synthesis of hydrogen peroxide in a novel Zn-CNTs-O2 system

A novel strategy of in-situ synthesis of hydrogen peroxide (H2O2) was formulated and evaluated. Oxygen was selectively reduced to H2O2 combined with electrochemical corrosion of zinc in the Zn-CNTs-O2 system. The ratio of zinc and CNTs, heat treatment temperature, and operational parameters such as composite dosage, initial pH, solution temperature, oxygen flow rate were systematically investigated to improve the efficiency of H2O2 generation. The Zn-CNTs composite (weight ratio of 2.5:1) prepared at 500 °C showed the maximum H2O2 accumulation concentration of 293.51 mg L−1 within 60 min at the initial pH value of 3.0, Zn-CNTs dosage of 0.4 g and oxygen flow rate of 400 mL min−1. The oxygen was reduced through two-electron pathway to hydrogen peroxide on CNTs while the zinc was oxidized in the system and the dissolved zinc ions convert to zinc hydroxide and depositing on the surface of CNTs. It was proposed that the increment of direct H2O2 production was caused by the improvement of the formed Zn/CNTs corrosion cell. This provides promising strategy for in-situ synthesis and utilization of hydrogen peroxide in the novel Zn-CNTs-O2 system, which enhances the environmental and economic attractiveness of the use of H2O2 as green oxidant for wastewater treatments.

Rheology in shear and elongation and dielectric spectroscopy of polystyrene-block-poly(4-vinylpyridine) diblock copolymers

We elucidate the influence of composition (weight ratios of 89/11, 76/24 and 49/51) and morphology (spherical, cylindrical and lamellar) on the dielectric and viscoelastic properties in shear and elongation of anionically synthesized polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers in the microphase-separated state. The temperature dependence of the response in both experiments is compared. The analysis of the linear regime shows the appearance of composition (superposition of moduli) and interfacial effects caused by microphase separation (low frequency shoulder, plateau and ω1/2 regime for dynamic moduli and Maxwell-Wagner-Sillars polarization in dielectric experiments). In shear and extensional flows with a constant deformation rate, a pronounced strain-softening behavior in case of a cylindrical and a lamellar morphology appears. For a high weight fraction of the majority phase and a spherical morphology, respectively, strain-softening is observed to a lesser extent. Consequently, strain-softening of diblock copolymer melts can be tuned by the weight/volume ratio of the two blocks.

Development of Flexible Energy Storage Device by Using Polymer Electrolyte Based on Ionic Liquid

AbstractA flexible supercapacitor composed of the reduced graphene oxide / acid‐treated single‐wall carbon nanotubes (rGO/ASWCNTs) composite (weight ratio of 1:9) electrode with the polymer based gel electrolyte was fabricated via spray coating technique. The ionic liquid based polymer electrolyte (IL‐b‐PE) was prepared by using polyvinyl alcohol (PVA) and 1‐Butyl‐3‐methylimidazolium tetrafluoroborate (BMIMBF4), which was able to fabricate full device as flexible supercapacitor. The electrochemical performances evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge / discharge (GCD) measurements. The flexible supercapacitor with the ionic liquid based polymer electrolyte (IL‐b‐PE) exhibited enhanced electrochemical performances compared to the flexible supercapacitor with PVA‐H3PO4 gel electrolyte. The electrochemical properties of the flexible supercapacitor assembled by IL‐b‐PE were investigated as a function of bending cycles. The cycling stability of the flexible supercapacitor was analysed as the function of bending test (0∼300) and GCD cycles (0∼4000). The specific capacitance value of the flexible supercapacitor (unbent) was 62.4 F g−1, which decreased to 55.7 F g−1 (89.3% retention after 1000 GCD cycles. The flexible supercapacitor was retained 64.6% (40.3 F g−1) of its initial capacitance value (62.4 F g−1) after 300 bending with application 4000th GCD cycles.

Axial and flexural behavior of unreinforced and FRP bar reinforced circular concrete filled FRP tube columns

Fiber Reinforced Polymer (FRP) composites have emerged as a viable alternative of steel reinforcement due to higher ultimate tensile strength to weight ratio and corrosion resistance of FRP composites. Concrete Filled Fiber Reinforced Polymer Tube (CFFT) technique for new column construction has attracted significant research attention. This paper investigated the axial and flexural behavior of Concrete Filled Carbon FRP Tube (CFRP CFFT) columns with and without CFRP bar and concrete filled Glass FRP (GFRP) tube columns with and without GFRP bar. The test results of 16 circular CFFT and four steel Reinforced Concrete (RC) specimens of 203–205mm diameter and 800–812mm height have been reported in this paper. The test results showed a larger reduction in the confinement effectiveness of FRP tube than steel helices under increasing applied load eccentricity. FRP bar reinforced CFFT specimens exhibited higher axial loads, flexural loads, and deformations at peak loads than unreinforced CFFT and steel RC specimens. Experimental axial load-bending moment interaction curves of tested specimens also showed the improved performance of FRP bar reinforced CFFT specimens.