Showing papers in "Materials research express in 2022"
TL;DR: In this paper , a review of carbon nanomaterials incorporated in the membrane filtration to treat wastewater contaminants is presented, focusing on these CNM based membranes and membrane technology, their properties and applications.
Abstract: Water is a necessity for all living and non-living organisms on this planet. It is understood that clean water sources are decreasing by the day, and the rapid rise of Industries and technology has led to an increase in the release of toxic effluents that are discharged into the environment. Wastewater released from Industries, agricultural waste, and municipalities must be treated before releasing into the environment as they contain harmful pollutants such as organic dyes, pharmaceuticals wastes, inorganic materials, and heavy metal ions. If not controlled, they can cause serious risks to human beings’ health and contaminate our environment. Membrane filtration is a proven method for the filtration of various harmful chemicals and microbes from water. Carbon nanomaterials are applied in wastewater treatment due to their high surface area, making them efficient adsorbents. Carbon nanomaterials are being developed and utilized in membrane filtration for the treated wastewater before getting discharged with the rise of nanotechnology. This review studies carbon nanomaterials like fullerenes, graphenes, and CNTs incorporated in the membrane filtration to treat wastewater contaminants. We focus on these CNM based membranes and membrane technology, their properties and applications, and how they can enhance the commonly used membrane filtration performance by considering adsorption rate, selectivity, permeability, antimicrobial disinfectant properties, and compatibility with the environment.
28 citations
TL;DR: In this article , dissimilar aluminium alloys AA2014 and AA6063 are joined using the FSW procedure to achieve higher yield strength, ultimate tensile strength and microhardness, and experiments were planned as per response surface methodology (RSM) based central composite design (CCD).
Abstract: Welding dissimilar alloys of aluminium are quite cumbersome due to their lower melting temperatures and difficulty in welding. To resolve this, solid-state procedure friction stir welding (FSW) is utilized largely in industries. In this present research, dissimilar aluminium alloys AA2014 and AA6063 is joined using the FSW procedure to achieve higher yield strength, ultimate tensile strength and microhardness. Experiments were planned as per response surface methodology (RSM) based central composite design (CCD), for four input parameters (tool pin profile, rotational speed, axial force and traverse speed). Micrographs of the weld show grain refinement and proper fusion of materials which increases the mechanical strength and bonding. Outcomes from the experiment show that the considered input parameters significantly influence all the outputs. The optimum condition was evolved from multiobjective optimization procedure using desirability approach (DA) which are 1010 rpm rotating tool speed, 25 mm min−1 as tool traverse speed, 7 kN of axial force with triangular pin profile. The second-order regression model predicts the output responses with lower residuals and the confirmation experiment outputs produces a maximum deviation of 7.94% with investigational outcomes with optimum condition. Micrographs shows that the heat affected zone (HAZ) region is free from voids, oxides, and cracks. The nugget zone has the flow of materials from both the base metals and the flow track is clearly visible.
26 citations
TL;DR: In this article , the compressive and flexural strength of metakaolin-red mud/carbon nanotubes was investigated by using XRD, FTIR, and SEM measurements.
Abstract: In this research, the mechanical properties and structural studies of the geopolymer nanocomposite of metakaolin-red mud/carbon nanotubes were investigated. The geopolymer was designed by using metakaolin and red mud as aluminosilicate sources. Red mud replaced between 10 to 30% of the metakaolin. The mass ratio of the solid material and activator liquid was optimized in 1.5:1. Afterward, 1, 2, and 3 wt% multi-wall carbon nanotubes (MWCNTs) were dispersed in a polycarboxylate-based superplasticizer and were added to the geopolymer, which was mixed homogeneously. Geopolymer nanocomposites were characterized by XRD, FTIR, SEM, compressive and flexural strength measurements. The results indicated that the compressive and flexural strengths of the samples increased with curing time. The addition of red mud decreased the compressive and flexural strength of the geopolymer samples due to less reactivity and presence of a non-reactive impurity in red mud. By adding 2% MWCNTs, the compressive and flexural strengths increased to 37.05% and 36.06%, respectively, owing to the crack-bridging mechanism and filling of the cavities and porosity. FTIR spectra demonstrated the growth of the asymmetric stretching vibrations of T–O–Si (T: Si or Al) at approximately 995.85–1083.55 cm−1, confirming the realization of the geopolymerization process in the structure.
22 citations
TL;DR: Chitosan has become the most known and second abundantly available recyclable, nonhazardous and eco-friendly biopolymer after cellulose with several advantageous biomedical, agriculture, and wastewater treatment applications as mentioned in this paper .
Abstract: Chitosan has become the most known and second abundantly available recyclable, non-hazardous and eco-friendly biopolymer after cellulose with several advantageous biomedical, agriculture, and wastewater treatment applications. As nanotechnology has progressed, researchers have begun incorporating chitosan-based carbon compounds into various compounds, elements, and carbonaceous materials to increase their efficiency and biocompatibility. Chitosan carbon compounds have also been used directly in many applications due to their inherent chelating and antibacterial features and the presence of customizable functional groups. This review widely discusses- the properties and synthesis of chitosan and chitosan composite. It also discusses the modification of chitosan with different compounds, metals, carbonaceous materials, and agriculture residues to allow their use on an industrial scale. Recent advances in the use of chitosan in biomedical, agro-waste management, agriculture, wastewater treatment, and a few other applications (such as food packaging, cosmetics, and the textile and paper sector) are briefly discussed. Furthermore, this analysis reveals that chitosan and its composite materials are potential, low-cost products for environmental clean-up that can be made with basic manufacturing procedures.
19 citations
TL;DR: In this paper , an out-of-plane low field dielectric constant ϵ ∥ = 3.4 ± 0.2 consistent with the theoretical prediction of Ohba et al.
Abstract: In view of the extensive use of hexagonal boron nitride (hBN) in 2D material electronics, it becomes important to refine its dielectric characterization in terms of low-field permittivity and high-field strength and conductivity up to the breakdown voltage. The present study aims at filling this gap using DC and RF transport in two Au-hBN-Au capacitor series of variable thickness in the 10–100 nm range, made of large high-pressure, high-temperature (HPHT) crystals and a polymer derivative ceramics (PDC) crystals. We deduce an out-of-plane low field dielectric constant ϵ ∥ = 3.4 ± 0.2 consistent with the theoretical prediction of Ohba et al, that narrows down the generally accepted window ϵ ∥ = 3–4. The DC-current leakage at high-field is found to obey the Frenkel-Pool law for thermally-activated trap-assisted electron transport with a dynamic dielectric constant ϵ ∥ ≃ 3.1 and a trap energy Φ B ≃ 1.3 eV, that is comparable with standard technologically relevant dielectrics.
17 citations
TL;DR: In this article , the performance of a lead-free perovskite solar cell (PSC) constructed from lead free inorganic materials was investigated and the best performance was achieved by optimizing several variables related to the performance, such as the thickness and defect density of the absorber layer, the doping densities, the back contact work and the operating temperature.
Abstract: The poisoning potential of lead, which is the main component of the absorber layer of lead halide (Pb) perovskites, as well as the stability problems of the manufactured devices, constitute a major obstacle to the industrialization of this technology. As a result, recent research is concentrating on lead-free metal halide perovskites. Unfortunately, current lead-free perovskites suffer from poor performance, hence the interest of our study. The research presented here shows that optimizing several variables related to the performance of each layer of a perovskite solar cell (PSC) constructed from lead-free inorganic materials provides an efficiency of 18.13%. We designed a structure with outstanding performance using the FTO/PC60BM/CsSn0.5Ge0.5I3/Spiro-OMeTAD/Au configuration. The impact of various relevant factors, such as the thickness and defect density of the absorber layer their doping densities, the back contact work, and the operating temperature, have been thoroughly investigated to boost the performance of the proposed device. The performance of cesium-tin-germanium triiodide (CsSn0.5Ge0.5I3) solar cells with different electron transport materials, including ZnO, TiO2, CdS, C60; Cd0.5Zn0.5S, IGZO, has also been examined. It has been demonstrated that using ZnO as an electron transport layer improves electron extraction and, therefore, performance. The best outcomes are obtained after optimizing all the factors mentioned above, namely: Jsc of 28.70 mA/cm2, Voc of 1.115 V, FF of 87.86%, and PCE of 18.13%. Additionally, the explored structure may be an excellent candidate for the future development of lead-free perovskite solar cells.
17 citations
TL;DR: In this article , a 3 mm ZK60 magnesium alloy sheet was carried for friction stir processing and the best processing parameters with a small grain size and maximum mechanical properties were obtained by comparing different rotation speeds and processing speeds.
Abstract: Abstract Friction stir processing is an important method for acquiring ultrafine-grained materials. In this paper, 3 mm ZK60 magnesium alloy sheet was carried for friction stir processing. The best processing parameters with a small grain size and maximum mechanical properties were obtained by comparing different rotation speeds and processing speeds. Fine recrystallized grains and high-angle grain boundaries were observed in stirring zone under different processing parameters. With increasing rotation speed, the grain size and high-angle grain boundary ratio increase; while with increasing processing speed, the grain size decrease, and the ratio of high-angle grain boundaries increase. When rotation speed and processing speed are 1400 r·min −1 and 100 mm·min −1 , the processing plate have the largest ultimate tensile strength are 267.52 Mpa, that reached 84.62% of the base metals, and the yield strength, elongation and grain size are 166.97 Mpa, 15.32% and 1.12 ± 1.64 μ m, respectively. The processing plate has more excellent damping performance than rolled.
16 citations
TL;DR: In this article , a comprehensive review on the application, and indeed a comparative analysis on dry machining of different types of materials used in machining (turning, drilling and milling operations) were carried out in the light of the literature.
Abstract: In this article, the comprehensive review on the application, and indeed, a comparative analysis on dry machining of different types of materials (Inconel, steel, aluminum, cast iron, magnesium and advanced materials) used in machining (turning, drilling and milling operations) were carried out in the light of utmost works published in the literature. The work describes the scientific findings of the past twenty years, including sustainable methods (surface texture, solid lubricants, vibration-assisted machining, laser-assisted machining), tool coatings, and geometry of tools. Vibration-assisted machining is another direction that researchers have investigated without the use of cutting coolants, where the complete disposal of coolants is not possible. Various researchers have carried out rigorous experimental work on milling, drilling, and turning operations under dry conditions to machine numerous materials. A significant proportion of experimental data about tool wear, tool wear machining, surface quality, surface integrity, etc, has been analyzed under dry conditions. However, the critical analysis of dry machining for different conventional machining operations for a variety of industrial materials is still lacking for establishing dry machining as a sustainable process for industrial applications. Thus, the critical analysis of various machining parameters and their consequences on tool wear and the surface quality of machined work was carried out in this work. Finally, scientific recommendations based on critical findings were proposed for industrial implementation of dry machining.
13 citations
TL;DR: In this article , a review of thin-film technology for the design and fabrication of sensors that are used in various applications is presented, including biomedical, energy harvesting, optical, and corrosion applications.
Abstract: Thin film sensors are used to monitor environmental conditions by measuring the physical parameters. By using thin film technology, the sensors are capable of conducting precise measurements. Moreover, the measurements are stable and dependable. Furthermore, inexpensive sensor devices can be produced. In this paper, thin film technology for the design and fabrication of sensors that are used in various applications is reviewed. Further, the applications of thin film sensors in the fields of biomedical, energy harvesting, optical, and corrosion applications are also presented. From the review, the future research needs and future perspectives are identified and discussed.
12 citations
TL;DR: In this article , Si3N4 strengthened high strength AA7068 nanocomposites via novel ultrasonic-assisted stir casting method advanced with bottom pouring setup in the proportion of 0.71, 50.07%, and 27.41 % was noticed in hardness value, tensile strength, and compressive strength.
Abstract: Ceramic particulate embedded aluminum metal matrix nanocomposites (AMNCs) possess superior mechanical and surface properties and lightweight features. AMNCs are a suitable replacement of traditional material, i.e., steel, to make automotive parts. The current work deals with developing Si3N4 strengthened high strength AA7068 nanocomposites via novel ultrasonic-assisted stir casting method advanced with bottom pouring setup in the proportion of 0.5, 1.0, 1.5, and 2 wt.%. Planetary ball milling was performed on a mixture of AA7068 powder and Si3N4 (in the proportion of 3:1) before incorporation in aluminum alloy melt to avoid rejection of fine particles. Finite element scanning electron microscope (FESEM), Energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD), and Elemental mapping techniques were used in the microstructural investigation. Significant grain refinement was observed with increasing reinforcing content, whereas agglomeration was found at higher weight %. Hardness, Tensile strength, ductility, porosity content, compressive strength, and impact energy were also examined of pure alloy and each composite. Improvement of 72.71%, 50.07%, and 27.41 % was noticed in hardness value, tensile strength, and compressive strength, respectively, at 1.5 weight % compared to base alloy because of various strengthening mechanisms. These properties are decreased at 2 wt.% due to severe agglomeration. In contrast, nanocomposite’s ductility and impact strength continuously decrease compared to monolithic AA7068. Fracture analysis shows the ductile and mixed failure mode in alloy and nanocomposites.
11 citations
TL;DR: In this article , low-density polyethylene waste was recycled in the form of fibers (LDPF) to produce eco-friendly fiber-reinforced sustainable self-compacting concrete (SCC).
Abstract: Sustainable concrete production and recycling the construction wastes are of utmost importance for today’s sustainable urban development. In this study, low-density polyethylene waste was recycled in the form of fibers (LDPF) to produce eco-friendly fiber-reinforced sustainable self-compacting concrete (SCC). The content of LDPF ranged from 0.5% to 3.5% at a raise of 0.5% of the mix’s volume. The SCC’s features in fresh and hardened states were tested. The slump flow diameter, T500, V-funnel, and L-box ratio were measured for the fresh properties. The compressive, splitting tensile and flexural strengths were tested at the age of 28 days. However, the outcomes indicated that LPDF had some negative effect on the workability features, but all the results of SCC mixtures were within the standard limitations of SCC except that related to the L-box, which satisfied the standards up to 2% of LDPF. However, the incorporation of LDPF enhanced the mechanical properties, especially the flexural strength. The optimum ratio for the LPDF was 2%, which satisfies the required workability and the highest strength with modulus of elasticity. The thermal conductivity decreased with increasing LDPF content in the SCC mixtures.
TL;DR: In this paper , the effect of curing conditions on the physical, mechanical, and micro-structural properties of specimens using ambient curing and oven-curing was identified, and it was concluded that the density, Poisson's ratio, and dry shrinkage were higher for ambient cured specimens than for oven cured specimens.
Abstract: Geopolymer concrete represents the future of green and sustainable concrete. It has a large impact on the construction industry owing to its better performance than that of conventional Portland cement concrete. This study aimed to identify the effect of curing conditions on the physical, mechanical, and microstructural properties of specimens using ambient curing and oven-curing. In the experimental analysis, we tested slump and setting time for physical properties, density and drying shrinkage for chemical properties, compressive strength, indirect tensile strength, modulus of rupture, Poisson’s ratio, and elastic modulus for mechanical properties, rebound strength, and UPVT for nondestructive and x-ray diffraction, and thermogravimetric analysis for microstructural analysis. After the experimental analysis, it was concluded that the density, Poisson’s ratio, and dry shrinkage were higher for ambient-cured specimens than for oven-cured specimens, whereas the compressive strength, indirect tensile strength, modulus of rupture, and elastic modulus of oven-cured specimens were higher than those of ambient-cured specimens. The nondestructive tests, rebound tests, and UPVT show that the oven-cured specimens are better in quality and strength than the ambient cured specimens. In microstructural analysis, x-ray diffraction showed that the oven-cured specimens had a lower intensity of mineral oxides than the ambient-cured specimens in microstructural analysis. The matrix of the ambient-cured specimens was thermally stable up to 800 °C and retained 92% of its original mass, whereas the matrix of the oven-cured specimens retained 94% of its mass up to 800 °C in the thermogravimetric analysis.
TL;DR: In this article , a review extensively sheds light on Artificial Intelligence models implemented in metal melting processes or the metal melting aspect, alongside explaining additive manufacturing as a competitor to the current melting processes.
Abstract: Artificial Intelligence has left no stone unturned, and mechanical engineering is one of its biggest consumers. Such technological advancements in metal melting can help in process simplification, hazard reduction, human involvement reduction & lesser process time. Implementing the AI models in the melting technology will ultimately help various industries, i.e., Foundry, Architecture, Jewelry Industry, etc. This review extensively sheds light on Artificial Intelligence models implemented in metal melting processes or the metal melting aspect, alongside explaining additive manufacturing as a competitor to the current melting processes and its advances in metal melting and AI implementations.
TL;DR: In this article , carbon fiber and Graphene nanoplatelets (GNP) of different weight percentages of GNP (0, 0.1,0.3, and 0.5 wt%) reinforced hybrid composites were fabricated via hand layup technique followed by compression molding.
Abstract: In this research, carbon fiber and Graphene nanoplatelets (GNP) of different weight percentages of GNP (0, 0.1,0.3, and 0.5 wt%) reinforced hybrid composites were fabricated via hand layup technique followed by compression molding. For wear analysis to understand the correlation between control parameters (wt% of filler, normal load, velocity, and sliding distance) and response measurements (weight loss), the design of experiments and analysis of variance (ANOVA) is used. The control variables such as normal loads (5, 10, 15, and 20 N), velocity (1, 2, 3 and 4 m s−1), and sliding distance (200, 300, 400, and 500 m) are selected for the research. It was observed that 0.5 wt% GNP-filled carbon fiber/epoxy composite shows higher tensile and flexural strength than another composite. It has been discovered that adding GNP reduces the wear in terms of weight loss. Scanning electron microscopy (SEM) was used to examine composites’ worn surfaces. The analysis concluded that experimental results are closer to optimum results.
TL;DR: In this article , the resistance of 3D graphene foam with a variance of temperature has been measured through an LCR meter and has been analyzed with classical and neutrosophic analysis.
Abstract: 3D graphene foam is the main aim of this research work. Graphene foam is synthesized on the Ni-foam by the CVD technique. The graphene foam has been characterized by XRD, FESEM, Raman spectroscopy and BET techniques. The resistance of graphene foam with a variance of temperature has been measured through an LCR meter and has been analyzed with classical and neutrosophic analysis. As a result, it is seen that graphene foam is expressing both conductor and semiconductor electric properties and also it is observed that neutrosophic analysis is more flexible to analyze the resistance of graphene foam.
TL;DR: In this article , the main intent of the study is to examine mechanically alloyed high entropy alloys critically for mechanical properties, tribological behavior, corrosion behavior, and functional properties.
Abstract: High entropy alloys are an innovative class of materials for a wide range of industrial applications due to their competitive properties such as improved mechanical properties, superior wear resistance characteristics, and excellent corrosion behavior, which are widely desired for a variety of applications considering several attributes such as economical, eco-friendly and safety. Thus, the quest for high-performance materials with exceptional properties is an unfading research topic for researchers, academia, and metallurgical scientists. HEA presents a novel alloy design idea focused on multi principal elements, a huge compositional space, and more opportunities to develop diverse alloys with exceptional properties. As universally acknowledged, the immense potential in compositions, microstructures, and properties has sparked a great interest in this field. Researchers primarily focused on equimolar HEAs, but the precedent eventually shifted to non-equimolar alloys. As the investigation over HEAs progressed, four core effects were identified as the most important aspects in enabling the distinct characteristics. Mechanical alloying (MA), followed by the sintering approach, has piqued the interest of all researchers focusing on HEA development. As a result, the main intent of this study is to examine mechanically alloyed HEAs critically for mechanical properties, tribological behavior, corrosion behavior, and functional properties. Furthermore, the predominant challenges and their conceivable prospects are also deliberated that offer novelty to this review article.
TL;DR: In this article , an updated theoretical treatment to model the results of Kelvin probe surface voltage and photovoltage measurements including four critical mechanisms: the concentration of charge stored in interface surface states, the charge storage in different locations of a surface dielectric thin film, the changes to effective lifetime and excess carrier density as a result of charge redistribution, and the non-uniformity of charge observed on most large scale thin film coatings used for passivation and optical improvement in optoelectronic devices.
Abstract: The characterisation of dielectric-semiconductor interfaces via Kelvin probe surface voltage and photovoltage has become a widespread method of extracting the electrical properties influencing optoelectronic devices. Kelvin probe offers a versatile, contactless and vacuum-less technique able to provide useful insights into the electronic structure of semiconductor surfaces. Semiconductor theory has long been used to explain the observations from surface voltage measurements, often by making large assumptions about the characteristics of the system. In this work I report an updated theoretical treatment to model the results of Kelvin probe surface voltage and photovoltage measurements including four critical mechanisms: the concentration of charge stored in interface surface states, the charge stored in different locations of a surface dielectric thin film, the changes to effective lifetime and excess carrier density as a result of charge redistribution, and the non-uniformity of charge observed on most large scale thin film coatings used for passivation and optical improvement in optoelectronic devices. A full model is drawn and solved analytically to exemplify the role that these mechanisms have in surface voltage characterisation. The treatment in this work provides crucial understanding of the mechanisms that give rise to surface potential in semiconductors. As such this work will help the design and development of better optoelectronic devices.
TL;DR: In this paper , the synthesis of Zinc sulphide (ZnS) nanostructures and their use as photocatalysts for the degradation of dyes and various antibiotics were reported.
Abstract: Abstract Pollutants such as dyes and pharmaceuticals have become a problem in the environment, thus there is a need to find multifunctional materials that are safe and can be used for the removal of various pollutants. In this study, we report on the synthesis of Zinc sulphide (ZnS) nanostructures and their use as photocatalysts for the degradation of dyes and various antibiotics. Fourier transform infrared spectroscopy (FTIR) confirmed the functional groups found in plants and these were linked to the biomolecules identified through Liquid chromatography-mass spectrometry (LCMS). Ultraviolet-visible spectroscopy (UV–vis) and x-ray diffraction (XRD) confirmed the formation of the ZnS nanostructures. Thermal Gravimetric Analysis (TGA) and Brunner Emmet Teller (BET) confirmed the material was thermally stable up until 480 °C and mesoporous in nature, respectively. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the material is spherical in shape and energy dispersive spectroscopy (EDS) further corroborated their formation. From the degradation analysis, 90% of the malachite green (MG) dye could be degraded in 60 min at optimum conditions (pH 6, 25 mg and 10 mg l −1 ) and the holes were responsible for the degradation. Lastly, when tested against antibiotics, the ZnS material managed to degrade both the sulfisoxazole (SSX) and sulfamethoxazole (SMX). These results showed that the ZnS nanoparticles could be used as a multifunctional material for the degradation of various pollutants.
TL;DR: In this paper , Niosomal sage nanoparticles (NS-SagNPs) were used to enhance the mechanical properties of chitosan films by doping at various concentrations (100-300 μg).
Abstract: Chitosan films are increasingly being applied in the biomedical field owing to their biocompatibility, biodegradability, non-toxicity, mucoadhesive nature, hemostatic properties, antibacterial and biological activities. This study aimed to enhance the mechanical properties of chitosan films by doping niosomal sage nanoparticles (NS-SagNPs) at various concentrations (100–300 μg). The NS-SagNPs were prepared by a thin-film hydration process with an average particle size of 21.5 nm. The doped chitosan films were fabricated through a simple casting method. FTIR and DSC measurements confirmed the successful incorporation of NS-SagNPs in the chitosan films. The mechanical properties of the doped films were improved and the most significant improvement was found in tensile strength and elasticity when the NS-SagNPs loading was increased to 300 μg. Based on these results, chitosan films doped with NS-SagNPs have the advantageous feature of sage and show enhanced mechanical properties compared with pure chitosan, rendering them more suitable for biomedical applications.
TL;DR: In this article , the effects of incorporating Sefri Date Palm Leave Fibers (SDPLF) into the mortar were investigated and the results showed that mortars with SDPLFs have lower workability, lower density, and lower compressive strength as compared to control mortars.
Abstract: This paper presents the results of a study conducted to investigate the effects of incorporating Sefri Date Palm Leave Fibers (SDPLF) into the mortar. A total of seven mixtures were prepared and tested. SDPLF were collected from local farms. The fibers were then cleaned, dried, and cut to different sizes of 10 mm, 20 mm, and 50 mm, maintaining the same individual fiber width of approximately 5 ± 2 mm. The content of SDPLF in mortars was kept to 1% and 3% by mass. The physical and mechanical properties of SDPLF fibers and SDPLF mortars were investigated. The compressive strength at 7, 14, and 28 days was determined. The water absorption rate test was carried out on mortars containing 1% SDPLF fibers. The results showed that mortars with SDPLF have lower workability, lower density, and lower compressive strength as compared to control mortars. However, they are still acceptable for use in construction works. Mortars containing 10 mm and 20 mm SDPLF fibers by mass showed significant improvement in terms of water absorption rate as compared to the control mortar.
TL;DR: In this article , a combination of poly(butylene adipate terephthalate) (PBAT) and polylactide (PLA) is used to process the material into blown films by fine-tuning the processing parameters.
Abstract: A blend of poly(butylene adipate terephthalate) (PBAT) and polylactide (PLA) is a combination of biodegradable materials. This study aims to prepare compatibilized PBAT/PLA in a cost-effective and timesaving way and to process the material into blown films by fine-tuning the processing parameters. First, a catalyst masterbatch is prepared by transesterification of PBAT and PLA in the presence of tetrabutyl titanate (TBT) as a catalyst. This is followed by the compounding of the two polymer types in combination with the catalyst masterbatch. Third, the compounds are processed into blown films and panels. The processing parameters for film blowing are set to reduce the anisotropy. Finally, the material properties are evaluated such as mechanical tests. The fine-tuning of parameter settings including the blow-up ratio and draw-down ratio results in a higher degree of isotropy of the blown film. By adding the catalyst masterbatch (2 wt%, which corresponds to TBT of approximately 0.002 wt% with copolymers formed) in combination with the fine-tuning of parameter settings, the samples achieved a significant improvement on the material properties. The morphology of the cryogenically fractured panel samples shows a decrease in the diameter of the dispersed phase. In the cross and machine directions, the elongation at break increased by 85 and 93%, and the trouser tear propagation resistance increased by 2.4 and 10 N mm−1, respectively. Furthermore, both the elongation at break and the trouser tear propagation of the blown films achieved a higher degree of isotropy.
TL;DR: In this paper , the effect of zirconia on mechanical properties such as hardness, compression strength, and thermal expansion coefficiency of Ti6Al4V alloy was investigated, and it was observed that 6 wt percentage of ZrO2 reinforced composite showed better characteristics in that the hardness and compression strength were the highest among all the proportions used and the coefficient of thermal expansion was low.
Abstract: This study investigated the mechanical and microstructural properties of ZrO2 reinforced titanium metal matrix composites (TMMCs) fabricated using powder metallurgy. The base matrix of the Ti6Al4V alloy was reinforced with ZrO2 at mixing proportions of different wt percentage points at 0, 3, 4, 5 and 6. Microstructure evaluation was carried out to study the bonding characteristics of the matrix and reinforcement, and it was confirmed that the reinforcement was homogenously mixed with the base matrix. The objective is to study the effect of zirconia on mechanical properties such as hardness, compression strength and thermal expansion coefficiency of Ti6Al4V alloy. The hardness, compression strength, and shrinkage rate are increased with the increase of ZrO2. Finally, it was observed that, 6 wt percentage of ZrO2 reinforced composite showed better characteristics in that the hardness and compression strength were the highest among all the proportions used and the coefficient of thermal expansion was low. Due to these promising results, the fabricated ZrO2 reinforced Ti6Al4V composite can be a potential material for structural, aerospace and automotive applications.
TL;DR: In this article , thin films of ZnO:Al were synthesized on glass substrates by RF magnetron sputtering and structural, optical, wettability and anti-icing properties of the thin films were studied as a function of substrate temperature and sputtering power.
Abstract: Thin films of ZnO:Al were synthesized on glass substrates by RF magnetron sputtering. Structural, optical, wettability and anti-icing properties of the thin films are studied as a function of substrate temperature and sputtering power. XRD patterns showed an increase in the intensity of (002) peak when the sputtering power and substrate temperature are increased. The roughness and average grain size also increased with an increment in substrate temperature and sputtering power. Transmittance and band gap energy observed in the wavelength range of 350–800 showed the average transmittance was in the range of 90 to 76% and 3.12–2.88 eV. The contact angle and anti-icing properties observed during the investigation demonstrated that the synthesized coatings are hydrophobic and the formation of ice was delayed when compared to uncoated substrates.
TL;DR: In this article , a beam-plasma discharge (BPD) was used to create conditions for chemical reactions and physical processes as close as possible to those possible in thermonuclear installations.
Abstract: Abstract The paper considers a method of tungsten surface carbidization using a beam-plasma discharge (BPD), which was implemented in a plasma-beam installation (PBI). The advantage of this method is to create conditions for chemical reactions and physical processes as close as possible to those possible in thermonuclear installations. The BPD makes it possible to generate plasma using different working gases. Methane was used as a plasma-forming gas. The working gas pressure in a chamber was (1,3–1,4)·10 –1 Pa. The temperature dependence of the carbidized layer formation on the tungsten surface under plasma irradiation was determined in the temperature range of 700 °C–1700 °C. The formation of tungsten carbides in surface layers was confirmed by SEM and x-ray diffraction analysis. It was found that interaction between tungsten and methane in a wide temperature range can proceed with simultaneous or sequential formation of the carbide phases W 2 C and WC.
TL;DR: In this article , the effect of silicon doping on the structural and optical properties of GaN/AlN heterostructures was studied and a particular mosaic structure was induced by the Si-doping as inferred from Rutherford Backscattering measurements.
Abstract: n-GaN/ AlN heterostructures were grown by molecular beam epitaxy on Si(111) substrates.The GaN films were n-type doped with silicon and the effect of doping concentration on the structural and optical properties was studied. Si doping promotes a reduction of dislocation density as revealed by x-ray data analysis and Transmission Electron Microscopy. Furthermore, a decrease in the yellow band measured by Photoluminescence Spectroscopy was observed when silicon doping concentration was increased up to 1.7 × 1019 atoms cm−3. A particular mosaic structure was induced by the Si-doping as inferred from Rutherford Backscattering measurements. The crystal quality shows a small degradation for very heavily doped samples (1.3 × 1020 atoms cm−3).
TL;DR: In this article , the surface properties of AA6061-T651 composites have been improved by using friction stir processing to reinforce Boron carbide (B4C) particles by the blind-hole method.
Abstract: Aluminum alloy-based surface composites have been in numerous applications since the introduction of the Friction Stir Processing (FSP) method to develop multifunctional properties owing to its ease of use and control in process parameters to obtain desired properties. AA6061-T651 is used as a substitute for AA6082 in structural applications due to its higher strength in comparison. To further improve the surface properties of AA6061, the friction stir processing technique was employed to reinforce Boron Carbide (B4C) particles by the Blind-Hole method. To achieve uniformity in distribution, FSP with a different direction strategy has been adopted. The surfaces thus developed were characterized using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. The grain size measurement was made on the processed samples using Heyn lineal intercept method. Tension and microhardness tests were also conducted to study the change in mechanical properties. The dark carbide zones with clear boundaries were identified in single pass processed specimens. Uniformity in the B4C distribution was observed on the dual-pass surface. In addition, Energy-Dispersive Spectroscopy (EDS) results have shown the presence of B4C embedded regions in the nugget zones along with the AA6061 matrix. Higher ultimate tensile strength was observed with the single-pass processed surface by 11% than the dual-pass processed surface.
TL;DR: In this paper , a comparison of the effect exerted by micro-texture and grain refinement and explored the existence of Sr and its influence on the second phase of 6063 Al alloys was performed.
Abstract: The micro-texture, grain size, morphology, size and distribution of the second phase in 6063 Al alloys significantly influence the comprehensive mechanical properties of alloys. By adding Sr to the 6063 Al alloys, this study performed a comparison of the effect exerted by micro-texture and grain refinement and explored the existence of Sr and its influence on the second phase. Inaddition, the influence mechanism for mechanical properties of the Sr-added alloys was also investigated. The results show that the phase structure of 6063 Al alloys is changed after adding Sr The Al2Si2Sr intermetallic compound is formed, and numerous substructures are developed during dynamic recovery and recrystallization. Moreover, after adding Sr element, the grain size of 6063 Al alloys is reduced from 33.45 μm to 24.04 μm. Small-angle grain boundaries increase, while large-angle grain boundaries decrease. Sr element changes the micro-texture of 6063 Al alloys significantly when Cube{100}〈001〉, Goss{110}〈001〉 and S {123}〈634〉 become Cube{100}〈001〉. The tensile strength, yield strength and Brinell hardness of 6063 Al alloys increase by 59.67%, 69.36% and 36.63%, respectively. Taken together, the Sr element strengthens the mechanical properties of 6063 Al alloys through fine-grained strengthening.
TL;DR: In this paper , the extrusion direction of the initial blank is changed to study the mechanical properties of the formed plates and characterize their microstructure, and the results show that the anisotropy of mechanical properties decreases obviously after secondary deformation.
Abstract: For an extrusion process of 7075 Al alloy, the extrusion direction of the initial blank is changed to study the mechanical properties of the formed plates and characterize their microstructure. The as-received bar is extruded 7075 Al alloy. The secondary extrusion deformation is along and perpendicular to the initial extrusion direction. The results show that the anisotropy of mechanical properties of the two samples decreases obviously after secondary deformation. The anisotropy of yield strength and ultimate tensile strength of ED90 sample is lower than that of ED0 sample, but the plastic anisotropy is slightly higher than that of ED0 sample. In addition, the recrystallized grain proportion of ED90 sample is high and the texture strength is low, so the Schmid factor in the three directions is similar. The tensile fracture mode of the two samples belongs to ductile fracture, but the morphology of dimple and the size of cleavage plane are slightly different.
TL;DR: In this paper , an all-inorganic perovskite-heterojunction CsPbI3/CsSnI3 is proposed as the absorber and the hole transport material (HTM)-free pervskite solar cells (PSCs) are investigated systematically through numerical simulation by using SCAPS-1D.
Abstract: The hole transport material (HTM)-free perovskite solar cells (PSCs) have attracted widespread interest due to enhanced stability and lowered cost as compared to the sandwich-type PSCs with an organic hole conductor. For the absorber layer, CsPbI3 has become a competitive candidate for its good chemical-components stability, excellent optoelectronic properties and most proper bandgap among inorganic halide perovskites. However, the power conversion efficiency of CsPbI3-based HTM-free PSCs is still much inferior to that of conventional ones. In this work, an all-inorganic-perovskite-heterojunction CsPbI3/CsSnI3 is proposed as the absorber and the HTM-free CsPbI3/CsSnI3 PSCs are investigated systematically through numerical simulation by using SCAPS-1D. Compared with the HTM-free PSCs employing a single CsPbI3 absorbing layer, the HTM-free CsPbI3/CsSnI3 PSCs have the extended absorption range and enhanced performance. The best cell efficiency is increased from 15.60% to 19.99% and from 13.87% to 19.59% for the cell with a back-front Au electrode and a back-front C electrode, respectively. It reveals that for the HTM-free CsPbI3/CsSnI3 heterojunction cells, C is a good choice for back-front electrode as it can achieve desirable cell performance with improved stability and lowered fabrication cost. These results indicate that the proposed HTM-free CsPbI3/CsSnI3 heterojunction cells are promising for photovoltaic applications.
TL;DR: In this paper , the authors examined the mechanical properties of the natural fiber reinforced hybrid composite that uses jute, snake grass, and kenaf fibers as reinforcement with various fiber volumes and showed that the wear behavior of the hybrid composites was enhanced by using Annona reticulata (custard apple) seed powder as a filler material.
Abstract: Natural fiber composites are hybridized nowadays to explore the synergetic effect of more fibers used in the properties of the composites. The natural fiber hybrid composite made with filler material has excellent wear resistance characteristics. This research work examined the mechanical properties, namely tensile, flexural, interlaminar shear strength, impact strengths, and hardness of the natural fiber reinforced hybrid composite that uses jute, snake grass, and kenaf fibers as reinforcement with various fiber volumes. Further, the wear behavior of the hybrid composites was enhanced by using Annona reticulata (custard apple) seed powder as a filler material. This study revealed that the sample has an equal proportion (12.5% of each) of snake grass and kenaf fiber (without filler) has excellent mechanical strengths. The wear behavior of the sample with 5 wt% filler shows a lower wear rate than other samples.