Varying Weight Percentages Research Articles

Identification of Plastics in Mixtures and Blends through Pyrolysis-Gas Chromatography/Mass Spectrometry.

In this paper, the possibility of detecting polymers in plastic mixtures and extruded blends has been investigated. Pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) allows researchers to identify multicomponent mixtures and low amounts of polymers without high spatial resolution, background noise and constituents mix interfering, as with molecular spectrometry techniques normally used for this purpose, such as Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy and differential scanning calorimetry (DSC). In total, 15 solid mixtures of low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyamide (PA) and polycarbonate (PC) in various combinations have been qualitatively analyzed after choosing their characteristic pyrolysis products and each polymer has been detected in every mix; thus, in extruded blends of high-density polyethylene (HDPE), PP and PS had varying weight percentages of the individual constituents ranging from 10 up to 90. Moreover, quantitative analysis of these polymers has been achieved in every blend with a trend that can be considered linear with coefficients of determination higher than 0.9, even though the limits of quantification are lower with respect to the ones reported in the literature, probably due to the extrusion process.

Optimization of Magneto-Electric Coupling in PVDF/PVDF-TrFE/Fe<sub>3</sub>O<sub>4</sub> Thin Film Nanocomposites for MEMS Sensor Devices

Magnetoelectric materials which simultaneously exhibit ferroelectricity and magnetism have attracted great attention in recent years due to their potent coupling effect, and potential application in the electronics industry. The work done in this study aims to investigate the effect of ferromagnetic (Fe3O4) nanoparticles on the thermal, mechanical, magnetic, and ferro-electrical properties of PVDF, and its co-polymer poly (vinlydene fluoride-co-trifluoroethylene), P (VDF-TrFE). These compounds are synthesized into flexible nanocomposite thin films, via a novel solvent casting method to influence crystallization and nucleation growth. Fe3O4 nanoparticles (NP) were integrated with polymers at varying weight percentages (1wt%, 3wt%, 5wt%, 7wt%, and 10wt %). Magnetoelectric nanocomposites were annealed at 150oC. Films were fabricated and processed at dimensions: 8-20μm thickness, 35 mm length, and 35 mm width. Neat and loaded samples are characterized using x-ray diffraction (XRD) to observe crystallinity and to obtain β - phase content distribution. Ferroelectric hysteresis loops are given from Radiant Multiferroic Analyzer, which resulted in an increase in peak polarization of 9.601μC/cm2 with the addition of 5wt% magnetite nanoparticles to P(VDF-TrFE) polymer blend. Magnetic tests are done using Vibrating Sample Magnetometer (VSM), which yields the magnetic polarization with respect to changes in field magnitude. The highest magnetic moment occurs with the addition of 10wt% Fe3O4 nanoparticles at 3.66 emu/g. Target applications of nanocomposites are for microelectromechanical system (MEMS) devices such as memory cards, spintronic, sensors, electromagnetic shielding, and compact energy storage.

Exploring tensile properties of bio composites reinforced date palm fibers using experimental and Modelling Approaches

The objective of this study was to assess the tensile strength of epoxy bio-composites reinforced with palm fibers, both untreated and treated with sodium carbonate NaHCO3 at a concentration of 10 % (w/v) for 24 and 96 h, with varying weight percentages of fibers (15 %, 20 %, 25 %, and 30 %). To predict the mechanical performance of the composites, two methods were employed: artificial neural network (ANN) and response surface methodology (RSM). A Box-Behnken RSM design was used to conduct experiments and establish a mathematical model of the bio-composite behavior as a function of the fiber percentage in the samples, specimen cross-section, and treatment time. The ANN forecasts showed consistent expected values for the bio-composite sample behavior, with a correlation coefficient (R2) greater than 0.98 for Young's modulus and 0.97 for stress. Similarly, the correlation coefficients obtained by RSM for the mechanical properties were also highly satisfactory, with an R2 of 0.89 for Young's modulus and 0.87 for stress. Finally, the errors generated by each method (Box-Behnken and ANN) were compared to the experimental results.

Enhanced electrochemical performance of in situ polymerized V2O5-PANI nanocomposites and its practical application confirmation by assembling ionic liquid as well as solid state-based supercapacitor device

In the present study, in situ polymerization of anilinium hydrochloride over V2O5 was used to prepare PANI nanocomposites with varying weight percentage of V2O5 (10, 20 and 30 wt%). V2O5 nanoparticles were synthesized using a simple chemical approach and their purity was confirmed through Rietveld refinement. It confirmed the advantageous electrochemical activity of V2O5 with a higher oxidation state of vanadium (V+5), enabling efficient electron storage. For fabricated electrode materials, the pair of redox peaks as well as their shape in CV suggests the faradic pseudocapacitive properties. Among all prepared electrodes, 20 wt% V2O5-PANI (PV2) nanocomposite demonstrates maximum specific capacitance of 820.5 Fg−1 at a current density of 1 Ag−1 with decent capacitive retention of 88 % after 1000 charge–discharge cycles. PV2 electrode also has a lower charge transfer resistance (Rct) of 0.5 Ω and lesser solution resistance (Ro) of 0.31 Ω in 6 M KOH electrolyte which is also responsible for good electrochemical performance. The higher capacitance value and decent stability of PV2 confirmed its ordered structure with more active sites shown through FESEM, which significantly contributes to efficient ion and electron transfer. In addition, the symmetric supercapacitor configuration of PV2 electrodes exhibits good energy and power densities of 4.6 Wh kg−1 and 80.7 W kg−1, respectively. Finally, the ignition of a red LED using three PV2//PV2 symmetric devices connected in series underscores its potential to advance energy storage applications.

β-Bi2O3-Bi2WO6 Nanocomposite Ornated with meso-Tetraphenylporphyrin: Interfacial Electrochemistry and Photoresponsive Detection of Nanomolar Hexavalent Cr.

Hexavalent chromium exposure via inhalation, ingestion, or both has been proven to adversely affect internal organs, induce toxic effects, cause allergies, and contribute to the development of cancer. It requires a substantial and challenging effort to detect several heavy metal ions conveniently, sensitively, and reliably by using materials that are easy to synthesize and have a high yield. The impact of light on the electrocatalytic oxidation/reduction process proves an environmentally friendly methodology with numerous applications in pollution control. The extensive use of photoactive materials in photoelectrochemical (PEC) sensors necessitates the development of stable and highly effective photoactive materials. Hence, the solvothermal synthesis of the organic-inorganic hybrid nanocomposite β-Bi2O3-Bi2WO6/H2TPP with varying weight percentages of meso-tetraphenylporphyrin (H2TPP) resulted in a selective electrode for electrocatalytic and photoelectrocatalytic reduction of Cr6+ on fluorine-doped tin oxide (FTO) by an adsorption-reduction mechanism. H2TPP increases the active site density and provides an effective surface area for efficient adsorption by providing both pyridinic- and pyrrolic-N atoms to β-Bi2O3-Bi2WO6/H2TPP. H2TPP could effectively adsorb Cr6+ in the β-Bi2O3-Bi2WO6/H2TPP composite system through electrostatic interaction, and the adsorbed Cr6+ ions were reduced to trivalent chromium Cr3+, resulting in promising Cr6+ sensing. The projected density of states and Bader charge calculations result in the electrostatic attraction among the N-2p orbital of H2TPP and the 3d and 4s orbitals of the Cr atom, resulting in the adsorption of the hexavalent Cr atom onto the active center of H2TPP. Moreover, the addition of H2TPP results in the development of a mesoporous surface that offers strong electrical conductivity, a substantial surface area, improved charge-mass transport, intimate contact between the electrolyte and catalyst, an extended fluorescence lifetime, and increased stability. The role of pH values was thoroughly investigated. All electrochemical and photoelectrochemical studies were carried out on 5 wt % H2TPP-ornated β-Bi2O3-Bi2WO6. Nanocomposite β-Bi2O3-Bi2WO6/5 wt % H2TPP demonstrated reliable cyclic stability, reproducibility, good sensitivity (8.005 μA mM cm-2), and a low limit of detection (LOD) (8.0 nM) toward photoelectrocatalytic reduction of Cr6+. The interference study in the presence of a few inorganic entities exhibited excellent selectivity. This tale amplification approach for developing a β-Bi2O3-Bi2WO6/5 wt % H2TPP nanocomposite system suggests a deeper understanding of the application of photoelectrocatalytic reduction of Cr6+ in environmental remediation with real samples under light irradiation.

In-situ influence of TiF3 catalyst on the hydrogen storage behavior of Mg-Ni-Y based alloy

Solid-state magnesium-based hydrogen storage encounters challenges associated with sluggish hydrogen absorption and desorption kinetics. The incorporation of catalysts is considered a promising means to improve the hydrogen absorption and desorption kinetics of these alloys. In this experiment, we prepared the Mg80Ni15Y5 alloy via vacuum melting and incorporated TiF3 in varying weight percentages of 1, 3, 5, and 7 wt% through ball milling. The phase composition and microstructure of the samples were analyzed and measured using X-ray diffraction meter (XRD), Transmission Electron Microscope (TEM), Selected Area Electron Diffraction (SAED), and Scanning Electron Microscope (SEM) techniques. The results revealed that the TiF3 introduced two catalytically phases, MgF and TiF2. And TiF2 transforms into TiH2 after hydrogen absorption, which covers the surface of MgH2 and prolongs the nucleation time of MgH2.Furthermore, the addition of TiF3 made the surface of alloy markedly coarser and more irregular and few cracks, providing channels for hydrogen diffusion. This behavior optimized the kinetic performance of the alloy. It was observed that the samples containing 7 wt%TiF3 achieved 99.2 % hydrogen saturation even in low-temperature. It's worth mentioning that the addition of 7 wt% TiF3 to the Mg80Ni15Y5 alloy significantly reduced the dehydrogenation activation energy to 58.5 kJ/mol, as opposed to pure magnesium with an activation energy of 158.2 kJ/mol. This substantial reduction has effectively accelerated the hydrogen absorption and desorption rates of the alloy. However, it had only a negligible impact on the thermodynamic properties of the sample with 7 wt%TiF3.

Development of green composites from bio‐benzoxazine and epoxy copolymer reinforced with alkali‐treated pine nut shell particles

AbstractIn the current study, an isothermal compression molding process was used to develop enhanced green composites made from alkali‐treated pine nut shell particles (TPS) reinforced in fully bio‐driven benzoxazine (VB) and epoxy (EP) copolymer. Reinforcement with varying weight percent (wt%) of bio‐filler enhanced the properties of composites. Composites showed a rise of 75.9 MPa, 5.8 GPa, and 5.1 kJ/m2 in flexural strength, modulus, and impact strength, respectively. Thermal stability shows that composites can endure higher temperatures and hence be classified as flame‐retardant materials. The dynamic mechanical analysis (DMA) confirms that composites exhibit higher storage modulus, which was elevated to 77.6% compared to the unfilled copolymer. FTIR spectroscopy analyzed the structure of copolymerized composites. Further, finite element analysis (FEA) was observed for the prepared composites. A transversely isotropic composite material model was created with the properties of composites, and stress analysis was observed. FEA outcomes are in good agreement with experimental findings.

Sustainable organosolv-lignin coated nanosilver-halloysites reinforced poly (vinyl alcohol) nanocomposites for wound healing application

This study involves the fabrication of innovative poly (vinyl alcohol) nanocomposite films by incorporating silver-embedded clay nanotubes with organosolv-lignin by the solution casting approach. The confirmation of this procedure was achieved through the utilisation of many techniques, including FTIR, PXRD, FE-SEM, and TGA. The aforementioned research have verified the adherence of silver nanoparticles to the surface of raw halloysites. The confirmation of lignin functionalization on these nanotubes has been established. This novel nanofiller was used to make a range of nanocomposite films with varying weight percentages ranging from 0 wt% to 5 wt%. With the increase in the wt% of nanofillers, These nanocomposite films exhibited greater thermal and mechanical stability compared to plain PVA. An investigation was conducted to examine the impact of the films on the cellular behaviour of murine fibroblast (NIH3T3) cell lines. Based on the findings from cell proliferation and scratch testing, it has been determined that these nanocomposite films are not harmful to cells, exhibit a greater rate of cell multiplication (116 ± 1.19), and demonstrate increased migratory capabilities (86.5 ± 0.50). Further investigations of human blood corroborate the evidence that these films are compatible with blood. Nanocomposite films have the potential to serve as wound healers following pre-clinical and clinical testing.

Enhancement of water absorption properties of date palm fibers-based composites via alkaline treatment

This study examined the ability of a biodegradable composite material to absorb water. The composites were created by combining a matrix of polylactic acid (PLA) with date palm wood fibers (DPWF) for reinforcement. Before incorporating the fibers into the polymer, they underwent chemical treatment using alkali solutions of NaOH and KOH. This treatment aimed to modify the surface properties of the natural fibers and enhance their water absorption capabilities. Different composites were fabricated, including PLA combined with untreated fibers (PLAUF), and PLA with treated fibers using both NaOH and KOH (PLAF-NaOH and PLAF-KOH), with varying weight percentages of fibers ranging from 0 to 40%. To evaluate the water absorption capability of the composites, water retention tests were conducted at room temperature (cold) and 50 °C (hot) for 24, 48 h and until the absorption reached equilibrium. The results demonstrated a significant enhancement in water retention, particularly in the case of the NaOH-treated samples, which exhibited approximately a tenfold increase in water retention compared to untreated samples. For example, the 20 wt% NaOH treated filler had a hot-water retention of 20%, compared to 2% for the untreated filler. Additionally, a higher percentage of filler resulted in a higher rate of water absorption. The 40 wt% NaOH treated sample with 20% water retention, absorbed 10 times more than the 10 wt% NaOH treated filler, with only 2% water retention. The developed composites have potential applications in natural gas dehydration processes, offering an alternative to the energy-intensive and environmentally harmful glycol-based dehydration methods currently in use.

Insights on the synthesis of iron-oxide nanoparticles and the detection of iron-reducing genes from soil microbes

This study explores the potential of some soil bacteria in the synthesis of iron oxide nanoparticles (IONPs), highlighting their advantages in terms of iron uptake and tolerance capacity. Soil samples collected from a metal fabricating workshop were successively screened in nutrient broth containing 1% iron salts (Fe2O3, FeCl3, and FeSO4) following a standard microbiological sampling technique. The recovered bacterial isolates (persister cells) were identified using polymerase chain reaction (PCR) and 16S rRNA sequencing. Ten bacterial isolates identified as Sporosarcina luteola, Bacillus badius (2), Bacillus subtilis (2), Bacillus tropicus, Bacillus cereus, Klebsiella pneumoniae, Klebsiella quasipneumoniae and Klebsiella africana were recovered. The method reports that six of the bacterial isolates extracellularly synthesize IONPs and the result from the energy dispersion x-ray (EDX) spectral analysis indicated varying weight percentages of bio-reduced iron by Bacillus subtilis-A12 (48.59%), Klebsiella quasipneumoniae (39.99%), Bacillus subtilis-B1 (39.97%), Bacillus cereus (38.62%), Bacillus badius (33.79%) and Klebsiella africana (32.61%). The IONPs exhibited absorbance peaks in the range of 250–350 nm, with a mean area size estimated between 31–72 nm using ImageJ software. Additionally, the presence of iron reductase (fhu) and cysteine desulfurase (suf) genes were detected in the recovered Bacillus and Klebsiella species through PCR analysis. This study has provided valuable insights into the physiology and genomic functions essential for microbial synthesis of IONPs and their relevance to nano-bioremediation.

Exploring the impact of heat treatment on the microstructural and compressive properties of Al-SiC-MWCNTs hybrid nanocomposites foams

The current study focused on the investigation of the microstructural and compressive properties of Al-SiC-MWCNT hybrid composite foams after the implementation of heat treatment. The samples were prepared with varying weight percentages of SiC and MWCNTs, with fixed porosity 86 % (relative density = 0.14). Initially, samples were subjected to solutionizing at 480 °C for 10h, followed by rapid water quenching. Subsequently, artificial aging was conducted by applying three different temperatures (150 °C, 180 °C, and 220 °C) for varying durations, ranging from 2 to 10h. The results revealed that significant improvement in mechanical properties and maximum peak compressive stress and microhardness were achieved between 6 and 8h and 8 and 10h, at the aging temperatures of 220 °C and 180 °C respectively. However, in the case of aging at 150 °C, mechanical properties also increased but at a slow rate, but no clear peak values were observed even after 10h of aging. It was observed that in case of HCF (both MWCNTs and SiC added as reinforcement) the plateau stress increased up to 30 to 40 %, whereas in case of AF, CF1, and CF2 foams the properties improved by 20 to 30 %. Also, by utilizing the established Gibson model, the plateau stresses were predicted and validated with experimental results.

Hydrothermal synthesis of cerium-doped Zn2SiO4 phosphor for futuristic lighting applications

In this study, Zn2SiO4:Ce3+ phosphor with varying weight percentages of cerium (Ce) was synthesized by using the hydrothermal process. The effect of Ce ion incorporation on the nanostructures, morphology, and optical characteristics was investigated by X-ray Powder Diffraction (PXRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray spectroscopy (EDX), Diffuse Reflectance Spectroscopy (DRS) using UV–Vis spectra, Photoluminescence (PL) spectroscopy, Commission Internationale de I'Elaairage (CIE)-1931 RGB color space diagrams and decay lifetime. According to PXRD measurements, Ce3+ ions were incorporated into the host material of Zn2SiO4, considerably altering their crystallinity. Due to strong crystallization, willemite crystal dispersion can be seen in FESEM images as rhombohedral-shaped crystals that successfully form closely packed grains, when the concentration of Ce3+ doping increased from 0 to 4 wt %, there was a noticeable reduction in the optical energy bandgap of the phosphor, which decreased from 5.01 to 3.22 eV. Photoluminescence spectra exhibited enhanced luminescent peak intensity at 591 nm emission, due to transitions of Ce3+ ions excited at 395 nm. Additionally, the luminescence intensity and decay lifetime of the Ce3+ ions in the Zn2SiO4 samples were determined using the tri-exponential fitting technique, and the average lifetime is 24.1 ns. This work provides valuable insight into the effect of doping element Ce3+ with various concentrations on the properties of luminescent Zn2SiO4, paving the way for its potential applications in advanced lighting technologies.

Effect of weight of Nanoclay on Tensile, Flexure and Toughness properties of Glass Epoxy composites

In recent times, polymer composites have played an epochal role in transforming material science. Some of their properties such as toughness, strength, flexibility, and rigidity have helped them supplant conventional materials such as iron, steel, and aluminium on several occasions. Apart from this, they are light in weight and more cost-efficient, which make them a viable alternative. They have found their application in several fields such as automobile industry, aerospace industry, construction, and pipeline industry. The present investigation uses composite material fabricated with varying weight percentages of Nano clay viz 1.5, 3.5, and 5 which are compared with Neat Glass Epoxy composite. The reinforcement material used is Glass fibre. Three different orientations viz unidirectional, Symmetric and Asymmetric of the laminate are considered. The fabricated composite is characterized for various mechanical properties like tensile test, flexure, and Fracture toughness testing as per ASTM standards. The addition of Nano Clay showed the improvement in the Tensile, Flexure and Fracture Toughness of the for 3.5 wt% of Nanoclay. The properties under tensile loading i.e. the tensile strength is increased by 12% for Unidirectional laminate, flexure strength increased by 20% for Unidirectional laminate and 20% for Unidirectional laminate fracture Toughness.after 3.5 wt%, there seemed to be a decline in both the properties. The morphological assessment was done by scanning electron microscopy (SEM) where the microstructure was analyzed. The SEM images were used to study the activity of the Nanoclay within the fabricated composite. The overall test results suggested that the fiber reinforced nanoclay composites can fit for industrial applications like condenser blades and turbine blades.

Highly-Efficient Ni@CuS/SGCN Nanocomposite with Superior Bifunctional Electrocatalytic Activity for Water Splitting

The contemporary world faces significant challenges with the depletion of non-renewable energy sources and the escalation of global temperatures. Using H2 as an energy source is a sustainable, renewable, and environmentally friendly alternative. Electrochemical water splitting using an efficient electrocatalyst is an optimistic approach for hydrogen production. The primary concern is the development of a durable, cost-effective, and highly efficient bifunctional electrocatalyst to enhance electrochemical water splitting. The present investigation employs CuS as the electrocatalyst, followed by the implementation of two techniques, doping and composite material synthesis, to enhance its electrocatalytic characteristics. CuS samples doped with varying weight percentages of Ni (2, 4, 6, 8, and 10 wt.%) and a composite material of 6% Ni@CuS with SGCN were synthesized using the co-precipitation method. The electrocatalysts were studied by characterization techniques such as SEM, EDX, FTIR, and XRD. Doping and composite material synthesis enhance the electrochemical water-splitting activity, as LSV, CV, EIS, and Chronopotentiometry analyses demonstrated. The electrochemical water splitting process exhibits maximum performance when utilizing Ni@CuS/SGCN, resulting in a low overpotential of 380 mV for OER and 178 mV for HER, achieving a current density of 10 mA cm−2. The findings indicate that composite Ni@CuS/SGCN can potentially serve as an electrocatalyst for water splitting.

First-Time Application of Underwater Live Concrete for Economic Retrofitting of Damaged Bridge Piers in Bangladesh

This paper presents a comprehensive analysis of the use of underwater concrete (UWC) in the retrofitting restoration of bridge piers in Bangladesh. In Bangladesh, UWC is a comparatively new technology, and this investigation represents the first instance of its application in practice. This study’s primary objective was to produce self-compacting, self-fresh concrete with minimal mass loss. To accomplish this objective, antiwashout admixture (AWA) was added to the concrete mix at varying weight percentages (0.1%, 0.2%, 0.3%, 0.4%, and –0.5%) to determine the optimal dosage of AWA that would result in the least amount of concrete washout. The slump and runoff resistance of the concrete mixture were evaluated, and it was observed that a certain percentage of AWA addition resulted in minimal cement mass loss. Furthermore, cost reduction was a major concern of this study, as it is essential to minimize project expenses. Thus, comparative cost analyses of various repair techniques were conducted to determine the most cost-effective approach for future underwater repairs.

Enhanced dielectric and hydrophobic behaviour of aurin based polybenzoxazine dye composites

Herein, three novel bi-functional benzoxazines were synthesized using aurin as the precursor phenol with three different aromatic amines (i.e.) aniline, fluoroaniline, and trifluoromethylaniline with paraformaldehyde through Mannich condensation. The structural confirmation was done using FTIR and proton NMR. The effects of substituents present in the amines on the curing behaviour and thermal stability were studied using DSC and TGA. The aurin based trifluoromethyl substituted benzoxazine shows better thermal stability than that of the other two benzoxazines and it was selected for the preparation of composites with varying weight percentages of graphitic carbon nitride derived from dicyandiamide (Dicy-GCN) to utilize them for high k applications. The dielectric behaviour and thermal properties of both neat polymer matrix and composites were studied and compared. The 15 wt% Dicy-GCN reinforced composite shows the highest dielectric constant value of 10.25, with a low dielectric loss value of 0.046 at 1 MHz frequency. The polybenzoxazine composites developed show better thermal stability and superhydrophobic behaviour than those of neat polybenzoxazine matrix. These properties ascertain that the aurin based bifunctional polybenzoxazines and its composites can be considered for high-performance high k applications.

Investigation of Material Loading on an Evolved Antecedent Hexagonal CSRR-Loaded Electrically Small Antenna.

Recent advances in embedded antenna and sensor technologies for 5G communications have galvanized a response toward the investigation of their electromagnetic performance for urban contexts and civil engineering applications. This article quantitatively investigates the effects of material loading on an evolved antecedent hexagonal complementary split-ring resonator (CSRR)-loaded antenna design through simulation and experimentation. Optimization of the narrowband antenna system was first performed in a simulation environment to achieve resonance at 3.50 GHz, featuring an impedance bandwidth of 1.57% with maximum return loss and theoretical gain values of 20.0 dB and 1.80 dBi, respectively. As a proof-of-concept, a physical prototype is fabricated on a printed circuit board followed by a simulation-based parametric study involving antenna prototypes embedded into Ordinary Portland Cement pastes with varying weight percentages of iron(III) oxide inclusions. Simulation-derived and experimental results are mutually verified, achieving a systemic downward shift in resonant frequency and corresponding variations in impedance matching induced by changes in loading reactance. Finally, an inversion modeling procedure is employed using perturbation theory to extrapolate the relative permittivity of the dielectric loaded materials. Our proposed analysis contributes to optimizing concrete-embedded 5G antenna sensor designs and establishes a foundational framework for estimating unknown dielectric parameters of cementitious composites.

MIL-100(Fe) /ZnO nanocomposite sensors: An enhanced ammonia selectivity and low operating temperature

This study aims to enhance the response and selectivity of zinc oxide (ZnO) gas sensors by its incorporating in MIL-100(Fe) as a support material. ZnO nanocomposites were synthesized by impregnating MIL-100 with varying weight percentages of zinc oxide (10% to 20%). The fabricated sensors underwent characterization through XRD, FTIR, DRS (UV-Vis), SEM/EDS, and NH3-TPD techniques to assess their material composition and sensor performance. DRS (UV-Vis) techniques revealed a significant decrease in the band gap, from Tauc analysis, accompanied by a 20% decrease in the Schottky barrier of the nanocomposite, compare to ZnO. Furthermore, the optimal operating temperature for the MIL-100/ZnO nanocomposites was identified as 240 °C, contrasting with pure ZnO sensors that exhibited an increasing response with temperature. Notably, the MIL-100/ZnO nanocomposites exhibited substantially improved selectivity for ammonia, displaying 3–6 times higher selectivity compared to pure ZnO sensors. Additionally, the response to ammonia increased threefold in the MIL-100/ZnO nanocomposites. This enhancement in selectivity and response can be attributed to the synergistic interaction between ammonia molecules and the Lewis acid sites present in the MIL-100 framework, facilitated by coordination bonds. The findings underscore the immense potential of MIL-100/ZnO nanocomposites as a promising solution for augmenting the selectivity of ZnO gas sensors. This work contributes valuable insights towards the advancement of gas sensing technology and paves the way for the development of highly selective gas sensors with extensive applications across various fields.

Tribological Behavior of SiC and Al2O3 Reinforced Aluminium Metal Matrix Composite

Stir casting offers greater benefits than other techniques for creating metal matrix composites. Using the high-energy stir casting process, the aluminium alloy Al5052 was strengthened with SiC and Al2O3 particles in varied weight percentages (0, 2, 4, and 6 wt.%). Through the use of XRD and SEM, the structural characterization was carried out. Investigations were made into mechanical characteristics such as hardness, tensile strength, and wear. To conduct wear studies, the load was changed while all other factors remained constant. SEM analysis was used to study the wear process. This study found that SiC and Al2O3 added to aluminium composites made them more resistant to wear. The findings demonstrated that when compared to base materials, the percentage of SiC and Al2O3 contained in the samples enhanced the mechanical characteristics, wear resistance, and hardness.

Green synthesized ZnO@CuO nanocomposites using Achyranthes aspera leaves extract for dielectric applications

ZnO@CuO Nanocomposites (NCPs) were synthesized using Achyranthes aspera plant’s leaves extract with varying weight percents of 25, 50 and 75 of ZnO. The leaves extract was prepared using laboratory distilled water with the help of magnetic stirrer at a temperature of 60ᵒC. An appropriate amount of zinc nitrate and copper nitrate were then mixed in the extract. ZnO@CuO NCPs were obtained after calcination of paste at a temperature of 400ᵒC. The annealed samples were characterized using various characterization techniques such as x-ray diffraction (XRD) spectroscopy, field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy and UV–vis spectrophotometry. FESEM images showed spherical morphology for CuO and ZnO@CuO NCPs, whereas, ZnO exhibited nanocapsules like morphology. The XRD patterns and FTIR spectra of green synthesized CuO and ZnO confirmed the formation of single-phase crystalline structure with monoclinic and hexagonal lattices. The XRD patterns of ZnO@CuO NCPs exhibited both phases corresponding to CuO and ZnO. FTIR spectra indicated all characteristic absorption bands of CuO and ZnO nanoparticles, which along with XRD Patterns confirmed the formation of ZnO@CuO NCPs. The optical band gap energy was calculated through Tauc’s relation using UV-Vis absorbance data and was found in the range of 1.54–3.05 eV. Optical band gap for nanocomposites is slightly less than that of pure ZnO and CuO nanoparticles. Dielectric studies established that the nanocomposites ZnO@CuO (25 and 50 wt% of ZnO) possess higher dielectric constant (K), dielectric loss and AC conductivity. ZnO@CuO (50 wt%) exhibits maximum dielectric constant of 14.49 × 103 with moderate dielectric loss. Hence, ZnO@CuO (50 wt%) could be a potential candidate for high K value device applications like capacitors and supercapacitors.