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Background: Aphis gossypii Glover (Hemiptera: Aphididae) is an economically important polyphagous pest species infesting many agricultural and horticultural crops causing severe yield losses. In order to develop biopesticides for the management of aphids in an environmentally safe manner, 6 indigenous entomopathogenic fungi Simplicillium subtropicum were isolated from soils of Tamil Nadu and their pathogenicity was tested against A. gossypii under laboratory conditions after characterization. Results: Phenotypic and molecular characterization was performed for all the isolates for species identification. Results of the pathogenicity test showed that the isolate S6 (PP446637) performed well among other isolates causing 58.33% mortality on 7 days after treatment (DAT) @ 1 × 108 spores/ml. The LC50 and LT50 values were found to be 2.36 × 107 spores/ml at 7 DAT and 160.20 h @ 1 × 108 spores/ml, respectively. SEM images of A. gossypii treated with the isolate S6 (PP446637) revealed that initial phase of infection, i.e., adhesion, formation of germ tube and appressoria starts within 24 h post-infection (hpi), hyphal development and penetration of cuticle occurred within 48 hpi and extrusion of mycelium and conidiogenesis occurred within 72 hpi. Conclusion: This study reveals the entomopathogenic potential of indigenous S. subtropicum isolates against A. gossypii and suggests their use for the eco-friendly management of aphids. [ABSTRACT FROM AUTHOR]

To study the influence of structural planes on rockbursts in the rock surrounding deep tunnels, a series of true triaxial compression tests were carried out on 100 mm × 100 mm × 100 mm red sandstone specimens (including 50 mm diameter circular holes and prefabricated structural planes). The characteristics of the rockburst process and acoustic emission under different structural plane conditions were studied, and the microscopic characteristics of the fracture surface were observed by scanning electron microscope (SEM). The test results show that: (1) The location of the initial damage and the mode and scale of the damage have changed significantly, regardless of the location of the structural plane and its exposure status. The existence of the structural plane will promote the occurrence of rock burst, and the intensity of the structural plane rock burst has also been greatly enhanced, but after the occurrence of the structural plane rock burst, the number and intensity of the rock burst are weakened. The failure process of the specimen with exposed symmetrical structural plane is dominated by slab spalling, and the initial failure position of the unexposed structural plane specimen is the corresponding position of the structural plane. (2) The existence of a structural plane changes the structure of the rock mass, and the transfer path of internal stress in the rock mass changes, It accelerates the overall failure of the specimen, has a significant "weakening effect" on the strength of the specimens, and the final damage of the specimen is more serious.According to the fracture behavior dominated by the structural plane, structural plane rockburst is divided into structural plane–plane pressure/column pressure rockburst and structural plane-buckling rockburst. Note that this failure mode may change with the distance between the structural plane and the hole and the nature of the rock. (3) According to the acoustic emission (AE) events, the existence of structural planes changes the scale of rockburst, the activity of acoustic emission is obviously enhanced, but the number of events is reduced, the generation of microcracks in the rock is reduced, and the proportion of shear cracks is increased. (4) Through SEM observation, the structural plane changes the energy transfer inside the rock mass, showing different micro-crack morphologies. A variety of crack morphologies are observed in the test samples containing structural planes, showing complex crack propagation modes, which means that the internal energy transfer path and scale have changed. The results of this study can enhance the understanding of the influence mechanism of structural planes on the rockburst in deep underground engineering. Highlights: A true triaxial physical simulation test of the rockburst process of surrounding rock with a structural plane near the boundary of a deeply buried tunnel was carried out. The existence of structural planes has significantly changed the development process of rockburst in deep tunnels. The existence of structural planes weakens the structural effect of circular holes in a rock mass. The existence of structural planes promotes the occurrence of rockburst, and an unexposed structural plane significantly increases the intensity of rockburst. [ABSTRACT FROM AUTHOR]

During the underground excavation, various flaws are frequently observed, which significantly decrease the mechanical properties of surrounding rock, as has been proven. As known, grouting technology is a means of reinforcement that efficiently enhances the stability of underground engineering. However, existing studies have mainly focused on increasing the strength of the slurry stone, and relatively less attention has been paid to the poor bonding effect at the interface between the slurry and the rock mass. In this work, we proposed to adopt slurry containing nano-silica sol to reinforce the fractured rock mass. Based on the mechanical model of micro–nano-siliceous slurry reinforcement for single fractured rock masses established in this paper, the effect and the mechanism of micro–nano-siliceous slurry reinforcement for fractured rock were explored through theoretical analysis, laboratory tests, and numerical simulations. Results showed that the application of micro–nano-siliceous slurry increased the friction and the bonding force at the slurry–rock interface, which led to a (σn·Δμ + Δc) reduction of the effective stress. The optimum incorporation rate of the nano-silica sol was determined to be 3% based on these indicators including slurry fluidity, slurry stone rate, and strength and deformation parameters of slurry stone. The peak strength of the sandstone specimens reinforced by the micro–nano-siliceous slurry increased by 16.49% those of the sandstones reinforced by the ordinary slurry, and the elastic energy accumulated by the former was higher. Scanning electron microscope images revealed that the incorporation of nano-silica sol distinctly improved the pore characteristics of the slurry-rock interface. Finally, on the basis of 1790 ventilation roadway of Shiyakou coal mine, the effectiveness and the feasibility of micro–nano-siliceous slurry for reinforcing underground engineering surrounding rocks were verified using numerical simulation. Highlights: This paper developed a new micro–nano-siliceous grouting material. A mechanical model for fractured rock mass reinforced by new slurry was proposed. The optimal incorporation rate of nano-silica sol was determined by various means. This study demonstrated the effectiveness of the new grouting material in reinforcing fractured rock mass by control lab experiments and numerical simulation. The mechanisms of micro–nano-siliceous slurry to improve slurry–rock interface were revealed. [ABSTRACT FROM AUTHOR]

In the present work, nanowire (NW) structured TiO2 nanoparticles were prepared using the hydrothermal method and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and BET specific surface area techniques. They were obtained in the anatase phase and presented a high surface area (ca. 300 m2/g). A commercial TiO2 (anatase, Merck) was used for comparison. The TiO2 catalysts were tested for photocatalytic oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 in water under UVA irradiation. The effects of acid treatment and subsequent calcination for TiO2 catalysts after the hydrothermal synthesis were also investigated. The sample, subjected to acid treatment and calcined at 300 °C (NW-HCl-300), showed the highest photocatalytic activity and selectivity towards the products. Consequently, this sample and Merck TiO2 were used to prepare polystyrene (PS)/TiO2 composites using the hydrothermal method. They were characterized by XRD, SEM–EDX, Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), UV–Vis, Gel Permeation Chromatography (GPC), and contact angle measurements and tested for PS (present in the composite) photodegradation. The results indicated that NW-HCl-300 had a high surface area, and was highly hydroxylated, favouring a good distribution of PS in the composite. The composite presented high thermal stability, but under UVA irradiation the polymer underwent solid-state photocatalytic degradation due to the contact with TiO2. The composite photodegradation was investigated using gravimetric, GPC, FT-IR, UV–Vis, and SEM techniques. [ABSTRACT FROM AUTHOR]

The immobilized horseradish peroxidase (P1-HRP) was prepared based on the affinity interaction between the phenylborate group in mVBA-b-p (AAm co AN) polymer (P1) and the adjacent dihydroxy group in horseradish peroxidase (HRP). The immobilization conditions of P1-HRP were optimized. Under the conditions of P1 concentration of 20 mg/mL, pH 8, temperature of 50 ℃, and immobilization time of 2 h, the HRP was immobilized to obtain the optimal immobilization amount (84.7 mg/g). The successful preparation of P1-HRP was demonstrated through characterizations such as laser scanning confocal microscopy (LCSM), scanning electron microscope (SEM), dynamic light scattering (DLS) and thermogravimetric analyzer (TGA). P1-HRP exhibited excellent pH stability, thermal stability and storage stability compared to the free horseradish peroxidase. P1-HRP had shown good application value in the degradation of phenol pollutants. After 10 repetitions of phenol degradation, the relative enzyme activity of P1-HRP could still be retained by 55.62%, indicating its good reusability. The optimal conditions for the catalytic degradation of phenol by P1-HRP were optimized. After catalytic degradation of phenol for 60 min under the same conditions, the degradation rate of P1-HRP (92.33%) was higher than that of free horseradish peroxidase (85.32%). [ABSTRACT FROM AUTHOR]

Failure analysis was performed on a prematurely failed high-speed steel work roll of a hot strip mill in an integrated steel plant to identify the root cause of failure. Visual observation of the fractured surface revealed that the surface was rough and spalled with no indication of fatigue marks. Microstructure investigation was conducted using an optical microscope and scanning electron microscope (SEM) with energy dispersive x-ray spectroscopy (EDS). The microstructure of the roll comprises MC, M2C and M23C6 carbides in a martensitic matrix. Acicular-shaped, coarse M2C carbides were distributed along the cell boundaries in the microstructure and these carbides escalate the sensitivity for crack propagation and decrease the spalling resistance of work roll during service. X-ray diffraction analysis of failed sample also confirmed the presence of M2C carbides. The microstructure constituents of the failed work roll were compared with the equilibrium solidification diagram generated from the chemical composition by JMat Pro. It is recommended from this study that the precipitation of coarse intercellular M2C carbides in high-speed steel work roll should be controlled by modifying the chemical composition and optimising the solidification/cooling rate. [ABSTRACT FROM AUTHOR]

Environmental pollution by toxic heavy metals is increasing at an alarming rate which demands the development of an appropriate analytical method to investigate and quantify the target analytes. In response to this call, polyaniline Titanium (IV) tungstomolybdate (PANI/TWM) nanocomposite was synthesized by incorporating polyaniline into Titanium (IV) tungstomolybdate using sol–gel method. The material was then characterized using X-ray diffraction (XRD), UV-Vis, Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA-DTA), and Scanning electron microscope (SEM-EDX). It was amorphous with appreciable thermal stability as it retained 65.2% of its ion exchange capacity (IEC) up to 600 OC. It acts as a bifunctional strong acid cation exchanger with an IEC of 1.58 meq/g for Na+ ions. Moreover, the high distribution coefficients (Kd) of 1572 and 928 mL/g for Pb(II) and Co(II), respectively, indicate its potential to treat these ions in an aqueous matrix selectively. Real sample treatment with the prepared material was undertaken for binary separation of selected metal ions in column mode and practically appreciable efficiency (90.3 to 96.8%) was achieved. Therefore, the synthesized material can be considered as a promising cation exchanger to treat an environmental matrix containing toxic heavy metals. [ABSTRACT FROM AUTHOR]

As the global environmental problems of energy shortage and pollution are becoming prominent, the trend of using natural fibers as the reinforcement in the composite is increasing. In this study, the hemp fiber mat-reinforced polylactic acid (PLA) composite was designed and fabricated. As the fiber and matrix have different water affinity, the plasma treatment was used to improve the interfacial properties between them. After plasma treatment, scanning electron microscope (SEM), water contact angle and X-ray photoelectron spectroscopy (XPS) detection were conducted, and the results showed the effectiveness of plasma treatment. To further improve the interfacial properties and impart the electromagnetic shielding to the composites, the graphite and carbon black were respectively added into the interface by the spraying method. The results showed that the composite in which the fiber mat was plasma treated and 10wt% graphite added had the highest bending strength, and the after-fracture morphology of this composite showed good damage resistance. The reason lies in the synergistic effect from the combination of graphite and plasma treatment. Additionally, the electromagnetic shielding effectiveness of the above composite had the highest value of 20.25 dB in X-band frequency range. [ABSTRACT FROM AUTHOR]

In the current study, the ability of an indigenous marine Actinomycete Nocardiopsis dassonvillei (NCIM 5124) to degrade poly(3-hydroxybutyrate)-PHB was examined. From the whole genome sequencing data of the organism, information regarding the PHB depolymerase gene and amino acid sequence (Accession number: MCK9871921.1) was retrieved. In silico studies indicated the presence of a signal peptide characteristic of extracellular enzymes. ProtParam tool predicted that the protein had a molecular mass of 42.46 kDa with an isoelectric point of 4.51. Aliphatic and instability index values suggested that the protein was stable and the observed GARVY value indicated its hydrophilic nature. 3D structure prediction and multiple sequence alignments revealed the presence of Type I catalytic domain [including the oxyanion histidine towards the N terminal, the catalytic triad with serine (as a part of GLSAG pentapeptide), aspartate and histidine], substrate binding and linker domain. The organism was able to grow on PHB in solid and liquid media and effectively degrade it. Maximum enzyme activity (1.8 U/mL/min) was observed after 5 d of incubation in Bushnell Hass Medium containing 0.1% PHB, 1.5% sodium chloride, at 30 °C, pH 7.5 with agitation at 130 rpm. Application of the organism in disintegrating films of PHB and its copolymers was successfully demonstrated on the basis of weight loss and scanning electron microscope analysis. To the best of our knowledge, this is the first report on production of PHB depolymerase with high efficiency by N. dassonvillei, an organism that holds promise in degrading PHB-derived waste material. [ABSTRACT FROM AUTHOR]

Silver nanowires (AgNWs) have excellent flexibility, unique optical transmittance and high conductivity. The polyol process is appropriate for preparing AgNWs due to its simplicity, effectiveness, low cost, and high yield. This work aims to investigate the effect of preparation parameters of the polyol process on the silver nanowires properties. The parameters include the controlling agent, molecular weight of the polyvinylpyrrolidone (PVP), the temperature, and the reducing agent. The amount of silver nanoparticles formed during preparation was used to determine the optimum preparation conditions. The transmission electron microscope (TEM) images showed minimal amount of Ag nanoparticles when using mixed molecular weight of PVP-40K, and PVP-1.3M at 150 °C with the assistance of copper chloride as a controlling agent. The prepared AgNWs had an average length of 3.7 µm and aspect ratio of 15.3. The fabricated electrodes were characterized using a scanning electron microscope (SEM) and four probe resistivity measurements. The electrical measurement of the AgNWs electrodes indicated that the surfactant thickness is a critical parameter in having low sheet resistance electrodes. Also, the optical transmission was affected by the amount of nanoparticles. The prepared electrode with high concentration of AgNWs and a minimal amount of nanoparticles exhibited 80% optical transmission. [ABSTRACT FROM AUTHOR]

Single-layer isophorone diisocyanate (IPDI) are one of the most popular self-healing microcapsules but suffers from low shell strength, poor heat resistance, stability and aging properties. In this paper, IPDI microcapsules were encapsulated into double-layer phenolic (PF)/polyurethane (PU) by a two-step process involving interfacial polymerization and in-situ polymerization. The prepared microcapsule composites were comprehensively characterized for their physical and chemical properties using optical microanalysis, scanning electron microscope, Fourier transform infrared spectroscopy, thermal gravimetric analysis and depth-sensing indentation analysis. Compared with the single-layer PU-IPDI microcapsule counterpart, the mechanical performance, thermal resistance, aging property and environmental stability of double-layer PF/PU-IPDI microcapsules were significantly improved. The epoxy coating was enhanced with the incorporation of 10 wt.% PF/PU-IPDI microcapsules, whose self-healing performance was evaluated by scratch corrosion test. The results demonstrated successful repair of coating scratches, along with the absence of corrosion on the coated steel substrate soaked in a 10 wt.% NaCl solution for 7 days. By comparing the tensile strength of epoxy coating before and after crack formation, it could be found that the self-healing efficiency was 57.9% when loaded with 10 wt.% of PF/PU-IPDI microcapsules in coating. This study highlights that the rational design of double-layer microcapsules integrated into the epoxy coating matrix could provide excellent anti-corrosion and self-healing properties. [ABSTRACT FROM AUTHOR]

Thorium biosorption by a green microalga, Chlorella Vulgaris, was studied in a stirred batch reactor to investigate the effect of initial solution pH, metal ion concentration, biomass dosage, contact time, kinetics, equilibrium and thermodynamics of uptake. The green microalgae showed the highest Th adsorption capacity at 45 °C for the solution with a thorium concentration of 350 mg L−1 and initial pH of 4. The amount of uptake raised from 84 to 104 mg g−1 as the temperature increased from 15 to 45 °C for an initial metal concentration of 75 mg L−1 at pH 4. Transformation Infrared Spectroscopy (FTIR) was employed to characterize the vibrational frequency changes for peaks related to surface functional groups. Also, the scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to determine the morphological changes and elemental analysis of the biosorbent before and after the sorption process. The Langmuir isotherm was in perfect agreement with the equilibrium empirical data of thorium biosorption and the highest sorption capacity of the Chlorella Vulgaris microalgae was determined as 185.19 mg g−1. Also, the results of kinetic studies show that the thorium biosorption process follows a pseudo-second-order kinetic model. The negative value of ΔG0 indicates spontaneity and the positive values of ΔH0 indicate the endothermic nature of the adsorption process. [ABSTRACT FROM AUTHOR]

Reactor pressure vessel (RPV) studs are key components of nuclear reactors, and their connection with flange ensures the sealing of the RPV under high-pressure and high-temperature conditions. In the present work, the external threads of the RPV stud were prepared by triaxial rolling, and the texture evolution of the external thread root material of an RPV stud was predicted by finite element analysis coupled with viscoplastic self-consistent simulations. The microstructure of the external thread root material of RPV stud was characterized by scanning electron microscope and electron back-scattered diffraction. The installation characteristics of the turned and rolled parts of the RPV stud were tested by installation and pretightening tests. It was found that the dynamic recrystallization at the external thread root formed ultrafine tempered sorbite grains, high-angle grain boundaries (47%), and strong {111} <110> and {111} <112> textures. In the installation and pretightening test, the residual elongation of rolled parts was reduced by 6% under the same loading pressure. The triaxial rolling process distributed the microstructure of the external thread root of the RPV stud in a gradient manner, resulting in improved stud installation characteristics. [ABSTRACT FROM AUTHOR]

Organic dyestuff are mostly toxic compounds that pose serious dangers to the environment. Adsorption using low-cost adsorbents is the most favorable method for its economic aspects. Recently, geopolymers have been introduced as an effective adsorbent for dyes and heavy metals. In this investigation, the synthesis of geopolymers from fired brick waste (Homra) was studied with full characterization using X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Brunauer–Emmett–Teller, Energy dispersive X-ray, Scanning electron microscope tests and Transmission electron microscopy. The synthesized nano-Homra geopolymer (NHGP) was then subjected to the removal of one of the most used basic dyes, Methylene Blue (MB). Adsorption optimization was applied using Response surface methodology to study dye adsorption by the synthesized nano-geopolymer. The independent variables studied were: temperature, contact time, and concentration of dye in the elimination process, which were varied in the range of (25–60 ℃), (10–180 min), and (20–300 mg/L) respectively. The results obtained from ANOVA indicated that the maximum removal efficiency of 95% and adsorption capacity of 80.65 mg/g at a temperature of 59 ℃, contact time of 163 min, and an initial concentration of 254 mg/L. The results showed that the data obtained from the adsorption of MB onto NHGP was compatible with the Pseudo second order (R2 = 0.9838) and Langmuir isotherm model (R2 = 0.9882). [ABSTRACT FROM AUTHOR]

Fucosterols have been widely studied for their antioxidant, anticancer, and anti-inflammatory properties. However, they have not yet been studied in the field of dentistry. This study aimed to determine whether pretreatment of dentin with fucosterol before resin restoration enhances bond stability in resin-dentin hybrid layers. After applying 0.1, 0.5, and 1.0 wt% fucosterol to demineralized dentin, microtensile bond strength (MTBS) and nanoleakage tests were performed before and after collagenase aging, and the surface was observed using scanning electron microscope (SEM). The fucosterol-treated group showed better bond strength and less nanoleakage both before and after collagenase aging, and the corresponding structures were confirmed using SEM. MMP zymography confirmed that the activity of MMPs was relatively low along the concentration gradient of fucosterol, and the FTIR analysis confirmed the production of collagen crosslinks. In addition, fucosterol exhibits cytotoxicity against Streptococcus mutans, the main cause of dental decay. The results of this study suggest that fucosterol pretreatment improves bond strength and reduces nanoleakage at the resin-dentin interface, possibly through a mechanism involving collagen cross-link formation via the inhibition of endogenous and exogenous MMP activity. This study demonstrates the potential of fucosterol as an MMP inhibitor in dentin, which contributes to long-term resin-dentin bond stability and can be used as a restorative material. [ABSTRACT FROM AUTHOR]

This article presents a detailed study of the variation of secondary electron emission as a function of the primary energy. This study is performed with a dedicated scanning electron microscope on the electrical property evolution of the magnesium oxide (100) single crystal. It is shown that the crystalline orientation has a significant influence on the intrinsic secondary electron emission at low energies below 7 keV, but for high energies, the loss function of the secondary energy extending more deeply, disperses before its release. As the incidence angle of the primary beam energy differs from the normal and takes important values, the secondary electron yield increases. The increase in the incidence angle has a similar and complementary effect on the current density growth. [ABSTRACT FROM AUTHOR]

The detailed study on impact of Yb3+ on spectroscopic and 1.54 μm broadband emission of Er3+ doped transparent oxyfluroborosilicate glass ceramics (GCs) with embedded CaF2 nanoparticles was presented. The studied GCs were prepared by controlled crystal nucleation and growth process at 450 °C/1 h. Thermogravimetry and differential scanning calorimetry results showed good thermal stability and fiber drawing capacity. The scanning electron microscope and transmission electron microscope studies confirmed the formation and the uniform distribution of CaF2 nanoparticles. Various radiative and laser characteristic features were calculated within the frame work of Judd–Ofelt theory. The NIR emission at 980 nm pumping showed an intense and broad emission band due to Er3+:4I13/2 → 4I15/2 transition. The emission spectra showed a quenching in luminescence beyond 3 mol% of Yb3+ doping confirming the optimized Er3+ and Yb3+ ratio as 1:3 for enhanced emission. The stimulated emission cross-sections and quantum efficiency decrease with increased Yb3+ doping due to concentration quenching and cross-relaxation transfer of energy among Er3+ and Yb3+ ions. The experimental investigations suggest that the BSEr1Yb3GC has higher proficiency for 1.54 μm broadband fiber lasers and optical amplifiers in S and C band communication windows. [ABSTRACT FROM AUTHOR]

In the current work, phytosynthesized Copper oxide nanoparticles (CuO-NPs) were obtained in facile and sustainable way utilizing leaves of Ocimum sanctum, to detect heavy metals from surface water. The presence of phytochemicals in the green extract helps in stabilizing the nanoparticle by reducing metallic Cu2+ to CuO-NPs. Further standard physical techniques like XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), UV-Vis spectroscopy and FESEM (Field-Emission Scanning Electron Microscope) confirmed the formation of CuO-NPs. The phytosynthesized CuO-NPs revealed spherical conformation with 40 nm average crystallite size, calculated by Scherrer's formula. A linear colorimetric behaviour of CuO-NPs was observed in the range of (10–400 nM) Pb2+ ions and the R2 value of 0.992 with limit of detection of 60 nM was observed. The UV-Vis spectroscopy results confirmed pronounced sensitivity and selectivity for Pb2+ ions among all the metals tested (Ba2+, Ca2+, Hg2+, K+, Mg2+, Na+, Ni2+ and Zn2+). Interference tests indicated no interference on adsorption of Pb2+ ions from aqueous solutions from other metal ions tested. Kinetic studies on Pb2+ adsorption by CuO-NPs revealed best fit to the equilibrium data of Freundlich isotherm. Besides, Pseudo 2nd order kinetics was observed to be much appropriate with R2 (linear regression coefficient) equal to 0.999 for the adsorption process. Thus, in this study phytosynthesized CuO-NPs could be a promising candidate for effective detection and elimination of Pb2+ ions from surface water making it potable. [ABSTRACT FROM AUTHOR]

This study explored thermal behavior of four kinds of chromium compounds such as CrO3, K2Cr2O7, K2CrO4, and Cr2O3 using thermogravimetry (TG) and differential scanning calorimetry (DSC) method under the oxygen (O2) and nitrogen (N2) gas atmosphere at varying temperatures (25 to 1600 ℃). A diverse of chromium compounds were carefully evaluated for the first time through this method, and the present work provides new, comprehensive and valuable information regarding the mentioned compounds. XRD technique and elemental analysis were applied in order to recognize the products at diverse decomposition stages. The obtained products were then investigated via a SEM electron microscope. Also, the form and the size of crystals were explored. Interestingly, the results obtained from both TG and DSC experiments in O2 and N2 atmospheres were identical. The thermodynamic data obtained from DSC experiments are reported in this work. Along with ∆H for each peak. It was shown that the decomposition product of K2Cr2O7 was also a mixture of Cr2O3 and K2CrO4 at 1400 °C. This study explored thermal behavior of four kinds of chromium compounds such as CrO3, K2Cr2O7, K2CrO4, and Cr2O3 using thermogravimetry (TG) and differential scanning calorimetry (DSC) method under the oxygen (O2) and nitrogen (N2) gas atmosphere at varying temperatures (25 to 1600 ℃). A diverse of chromium compounds were carefully evaluated for the first time through this method, and the present work provides new, comprehensive and valuable information regarding the mentioned compounds. XRD technique and elemental analysis were applied in order to recognize the products at diverse decomposition stages. The obtained products were then investigated via a SEM electron microscope. Also, the form and the size of crystals were explored. Interestingly, the results obtained from both TG and DSC experiments in O2 and N2 atmospheres were identical. The thermodynamic data obtained from DSC experiments are reported in this work. Along with ∆H for each peak. It was shown that the decomposition product of K2Cr2O7 was also a mixture of Cr2O3 and K2CrO4 at 1400 °C. [ABSTRACT FROM AUTHOR]

Three-dimensional printing (3DP) technology has shown great potential in rock mechanics and mining engineering due to its ability to create complex and customized objects with high precision and accuracy. At present, an emerging research focus is improving the mechanical properties of 3D-printed samples, which originally has low strength and stiffness, to match those of natural rocks. The objective of this study was to investigate the effectiveness of different post-treatments on the strength enhancement of 3D-printed gypsum samples. To achieve this goal, 3D-printed gypsum samples were subjected to different post-treatments including dipped infiltration treatment and vacuum infiltration treatment using different infiltrants: water, saltwater, ColorBond, and StrengthMax. Subsequently, each sample was subjected to ultrasonic wave velocity testing and uniaxial compression experiments to characterize their mechanical properties, CT scans to investigate their microstructural characteristics. Additionally, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) tests were conducted to explore the underlying reasons for changes in macroscopic strength. Finally, the physical characteristics and mechanical properties of untreated and post-processed 3D-printed gypsum samples were compared with natural rocks. The results showed that the strength of samples treated with water and saltwater was much lower than that of those treated with ColorBond and StrengthMax, while the porosity was the opposite. In water-treated and saltwater-treated samples, water or saltwater treatment can alter particle characteristics, but weak adhesive bonding and numerous pores result in low mechanical strength. Samples treated with Colorbond or StrengthMax exhibit improved strength due to effective gap filling and cohesive structure formation, with StrengthMax-treated samples showing higher strength despite having more pores than Colorbond-treated ones. Moreover, the physical and mechanical properties of these treated samples matched a wider range of natural rock types compared to the untreated samples. Highlights: This study investigates the impact of different post-treatments and infiltrants on the physical and mechanical properties of 3D-printed gypsum samples. A novel method is proposed in this study to quantitatively evaluate the degree of infiltration by comparing the changes in porosity before and after vacuum infiltration of 3D-printed samples based on 2D CT images. The study provides an in-depth analysis of the mechanisms responsible for the macroscopic strength enhancement in 3D-printed samples after vacuum infiltration treatment. Vacuum infiltration treatment using StrengthMax significantly improves the physical and mechanical properties of 3D-printed gypsum rocks, allowing them to replicate a wider variety of natural rocks compared to untreated samples. [ABSTRACT FROM AUTHOR]

Direct explosion welding makes it challenging to weld high-strength metals. Interlayer explosive welding was utilized to join the high-strength, low-melting-point aluminum alloy A7075 with the high-strength titanium alloy Ti–6Al–4 V. This method overcomes the challenges of directly welding such metals and widens the range of weldable parameters, thus facilitating more favorable welding conditions. The study effectively demonstrated the interlayer explosive welding process for A7075 with Ti–6Al–4 V using aluminum and copper interlayers. Microstructure and chemical content analysis of the bonded interfaces were conducted through optical microscope, scanning electron microscope, electron backscatter diffraction, and X-ray energy spectroscopy. The investigations found that the upper interfaces were flat and straight in shape, but the lower interfaces were wavy. Interdiffusion of components and compound formation occurred at the welded interface. In addition, grain refining took place at the bonding interface. Vickers hardness was used to measure hardness variations at the welded interface, and the mechanical properties of the bonded interface were examined using tensile shear, bending, and microtensile tests. The results confirm the practicality of interlayer explosive welding in producing high-strength, low-melting-point composites of A7075 and Ti–6Al–4 V. Microstructure analysis and mechanical testing at the weld interfaces of A7075/A1060/Ti–6Al–4 V and A7075/Cu/Ti–6Al–4 V composite plates revealed excellent bonding quality. Notably, compared to A7075/A1060/Ti–6Al–4 V composite plate, A7075/Cu/Ti–6Al–4 V composite plate performs better in mechanical tests, with tensile bending strengths of 137 MPa and 1321 MPa, respectively. Thinner interfacial melting zones were evident in the microstructure of the composite plate with a copper interlayer at the 30 mm explosive thickness parameter, correlating with improved performance in the microtensile test. [ABSTRACT FROM AUTHOR]

Single step surfactant assisted sol–gel technique was adapted to synthesize mesoporous tungstated zirconia (m-WZ). Amorphous WZs, with high surface area, were synthesized after calcination of as-synthesized materials at 550 °C for 6 h. These materials were well characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Textural properties were established from N2 adsorption–desorption isotherm, Scanning electron microscope (SEM) and Transmission electron microscopy (TEM). Pyridine adsorbed FTIR and NH3-TPD revealed reasonable amount of Brønsted and Lewis acid sites of m-WZs. m-WZs exhibited outstanding catalytic activities toward solvent free Knoevenagel condensation reaction of different aromatic aldehydes with malononitrile and ethyl cyanoacetate at room temperature. The developed catalysts were also employed to synthesize different industrially important fine chemicals. These catalysts had longer reusability and no visible drops were observed in catalytic activity even after several runs. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study that investigates the effect of fiber dimension on preventing spalling of ultra-high-performance concrete (UHPC). UHPCs with different dimensions of polypropylene (PP) fibers were prepared for permeability test at different temperatures and spalling test under ISO834 fire curve. Scanning electron microscope (SEM) observation was also conducted focusing on the fiber of a UHPC sample at the same location after it was subjected to elevated temperatures. The results of permeability tests and spalling tests showed that longer fibers of 12 mm and 18 mm and finer fibers of 28 μm and 33 μm were more beneficial for increasing the permeability of UHPC at high temperature, resulting in higher effectiveness on spalling prevention. Permeability measurements indicated a significant increase occurred at 150°C regardless of fiber dimensions; this increase plays an important role in spalling prevention. SEM results further testify that this increase can be attributed to the formation of microcracks caused by expansion of PP fibers. An aspect ratio of 300 is recommend for spalling prevention of UHPC, when 3 kg/m3 of PP fibers are used. [ABSTRACT FROM AUTHOR]

In this study, the polygonal structure of WO3 nanoparticles was constructed by the hydrothermal route, and the prepared materials were utilized for supercapacitor applications. The synthetic materials are WO3 nanoparticles in their monoclinic phase, according to the X-ray diffraction data. The morphologies of the WO3 samples are polygonal like and scanning electron microscope and transmission electron microscopy have confirmed it. To investigate the supercapacitance behavior of polygonal WO3, various techniques were used, such as galvanostatic charge–discharge, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The polygonal WO3 nanoparticle modified on Ni-foam as a working electrode has a specific capacitance value of 870 F g−1 at 0.25 A g−1. The polygonal structure of WO3 nanoparticle-coated Ni-foam electrodes was very stable compared to other fabricated electrodes over the 10,000 cycles. The fabricated polygonal structure of the WO3 electrode has high capacitance retention (100.2%) and high coulombic efficiency (99%). The polygonal structure of WO3 makes it a particularly effective electrode material and a substantially better candidate for energy storage, especially supercapacitors. [ABSTRACT FROM AUTHOR]

Objective: this study aimed to digitally compare wear behavior and retention between PEEK and nylon retentive inserts used in locator-retained, mandibular implant overdentures when attachment design and size were standardized. Materials and methods: A total of sixty-four inserts (32 PEEK and 32 nylon inserts); were picked-up in implant overdentures. Overdentures of both groups were submerged in artificial saliva and mounted to chewing simulator. After 480,000 chewing cycles (equivalent to 2 years of clinical use) all inserts were scanned by scanning electron microscope (SEM), then all acquired images were digitally analyzed by software to detect and compare quantitative and qualitative changes of inserts in both groups. On the other hand, retention of both groups was measured by universal testing machine and the collected data was statistically analyzed using one-way Analysis of Variance (ANOVA) test with significance level set at P ≤ 0.05. Results: PEEK inserts showed significantly higher mean retentive values compared to the nylon inserts in the control group. Also, PEEK retentive inserts exhibited statistically lower mean wear values than the control group P ≥ 0.000. Qualitative investigation revealed significant and more pronounced changes in the surface roughness of nylon inserts compared to PEEK ones. Conclusions: Regarding retention, wear behavior and dimension stability, PEEK can be recommended as retentive insert material in cases of locator-retained mandibular implant overdentures. Clinical relevance: PEEK inserts offer enhanced retention, reduced wear, and greater dimensional stability over two years time interval. Clinically, this reduces prosthodontic maintenance and adjustments, improving patient satisfaction and long-term prosthetic success. [ABSTRACT FROM AUTHOR]

Magnesium dichloride (MgCl2)-supported titanium catalyst with diisobutyl phthalate (DIBP) and 3,5-di-isopropyl 1,2-phenylene diethyl dicarbonate (CD1, non-phthalate) internal donor was synthesized using magnesium alkoxide precursor. Additionally, a catalyst without the internal donor was prepared for comparative analysis. The synthesized catalysts were characterized and compared with respect to composition, surface area, particle size and morphology. The effect of CD1-based magnesium dichloride-supported Z–N catalyst was investigated for propylene polymerization and compared with DIBP-based and without internal donor Z–N catalyst system. The catalyst system with the CD1 internal donor demonstrated a higher MFI in the resultant polypropylene, suggesting a superior hydrogen response during propylene polymerization compared to both the DIBP-based and the donor-free catalyst systems. The molecular weight of the polymer was studied through gel permeable chromatography and compared for all catalyst system. The scanning electron microscope image of the polymer resin indicates spherical morphology and exact replication of catalyst. Catalyst systems exhibiting such elevated hydrogen responses hold significant industrial relevance, especially demand of high MFI PP grades in the automotive industry. [ABSTRACT FROM AUTHOR]

We present the band gap engineering and morphological tuning of BaAl2O4:0.1% Sm3+, x% Tb3+ nanophosphors synthesized by citrate sol–gel method. Herein, the samarium (Sm3+) concentration is kept constant at 0.1%, while the concentration of terbium (Tb3+) is tuned from 0.5 to 2.5% with steps of 0.5%. X-ray diffraction confirms the hexagonal crystal structure of the BaAl2O4:0.1% Sm3+, x% Tb3+ nanophosphors. The reduction in crystallite size from 38 to 31 nm is noticed after doping and co-doping. Scanning electron microscope micrographs display evolution in morphology from multimodal grain-like structures to agglomerated pointy nanorods. Energy dispersive X-ray spectroscopy confirms all the main elements, although Sm is not detected due to the low content incorporated into the lattice. Transmission electron microscope results reveal that the particle size and shape can be controlled by varying concentrations of Tb3+. Diffuse reflectance spectra with the aid of the Kubelka–Munk function, reveal the energy band gap in the range of 2.6–5.3 eV. Under the excitation wavelength of 235 nm, photoluminescence studies reveal eight emission peaks located between 380 and 641 nm characteristic of Tb3+ ions. Upon the excitation wavelength of 402 nm, the emission spectra show four peaks positioned at 564, 601, 648 and 708 nm attributed to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2,4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions of Sm3+ ions, respectively. From the colour coordinate results, this nanophosphor can successfully play a significant role in green, yellow and red LED applications. [ABSTRACT FROM AUTHOR]

Cuticle quality can affect food safety by protecting poultry eggs from bacterial infection in the modern poultry industry. However, genetic factors related to cuticle nanostructure are not much reported due to limited bird models. In the current study, the genome-edited quail targeting myostatin (MSTN) gene was used to investigate the effect of MSTN mutation on the cuticle nanostructure and quality. To analyze nanostructure of the cuticle layer of the MSTN mutant and wild-type (WT) quail eggs, scanning electron microscope (SEM) images was taken. Thickness of the cuticle layer did not differ between the MSTN mutant and WT groups, but the size of the nanospheres in the surface of the cuticle layer was increased by MSTN mutation. In addition, increased size of the nanospheres in the MSTN mutant group was also shown in the upper region of the cross-sectional cuticle layer. Notably, both groups showed similar small-sized nanospheres in the lower region of the cuticle layer and the size was increased as they ascended to the upper region. The data suggested that MSTN mutation increased the size of the nanosphere in the upper region of the cuticle layer at a late phase rather than increasing the size of nanospheres in the lower region of the cuticle layer at an early phase of cuticle formation. However, the number of Escherichia coli attached to the surface did not differ between the two groups indicating no association between nanosphere size and bacterial attachment in quail eggs. The current study demonstrated a new function of the MSTN gene on regulation of cuticle nanostructure, for the first time. These results advanced our knowledge on the association between genetic factors and cuticle nanostructure and can be served as a reference to study the mechanism of cuticle formation in the future study. [ABSTRACT FROM AUTHOR]

A modified carbon paste sensor based on N,N′-(((ethane-1,2-diylbis(oxy))bis(2,1-phenylene))bis(methanylylidene))bis(pyridine-2-amine; BPA Schiff base as Cr(III) selective carrier was fabricated and studied in this work. The proposed sensor homogenization and mechanism of action was studied by infra-red (IR) and scanning electron microscope (SEM) with energy dispersive X-ray (EDX) tools. The sensor covered 1.0 × 10−7–1.0 × 10–1 mol L−1 linear range and a detection limit of 7.22 × 10–8 mol L−1 for Cr(III) with 20.17 ± 0.13 mV decade−1 Nernstian slope. 5 s was the response time of the prepared sensor and it was reproducible and stable for 3 months. The working pH range was 3.3–6.0 and it also works well to determine Cr(III) ion in presence of water miscible solvents up to 12.5% content of the methanol and 17.5% of ethanol. The electrode's selectivity was studied using separate and mixed solution methods for selectivity coefficients determination and the sensor showed good selectivity relative to a variety of metal ions (selectivity coefficients = 1.01 × 10−5–8.57 × 10−3). In addition, the practical analysis value of the sensor was demonstrated by measurement of Cr(III) quantitatively in mineral water, supplement and also as an indicator electrode in Cr(III) against EDTA potentiometric titration with good reproducibility (RSDs of 0.91–2.15%). [ABSTRACT FROM AUTHOR]

The self-supported Co–Fe LDH@Ni(OH)2 material is successfully prepared on a foam nickel substrate through two hydrothermal processes. The phase structure and microstructure of the electrode material are investigated through X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) analyses. The electrode materials undergo electrochemical and electrocatalytic tests using an electrochemical workstation. This study demonstrates that the specific capacitance of the Co–Fe LDH@Ni(OH)2 is 2626 mF cm−2 at 1 mA cm−2. Supercapacitors made of LDH@Ni(OH)2 electrode material operate exceptionally well. Both the power density and the energy density are 0.755 mW cm−2 and 32.5 μWh cm−2, respectively. As a catalyst material for electrochemical splitting of water, CoFe-LDH@Ni(OH)2 exhibits distinguished electrocatalytic properties. The overpotential is 242 mV at 50 mA cm−2 in HER, while that is 149 mV at 20 mA cm−2 in OER. Meanwhile, the CoFe-LDH@Ni(OH)2 electrocatalytic material also performs extremely well in the overall water electrolysis testing. The voltage is 1.65 V at 25 mA cm−2, which shows strong cyclic stability. The material provides a reliable guarantee for sustained and stable operation in various application scenarios. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide(MoS2) has a special structure and excellent mechanical properties, making it a promising reinforcing filler for polymers. Carbon dots (CDs) have good antioxidant properties, and the addition of CDs during the synthesis of MoS2 can affect its morphology and size. In this work, a new one-step hydrothermal synthesis process was employed to prepare CDs/MoS2 hybrid particles. Thiourea, sodium molybdate, and glucose were employed as sources of sulfur, molybdenum, and carbon, respectively. The structure and morphology of MoS2 and CDs/MoS2 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), mapping surface scanning (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR). The results show that the prepared 2H-MoS2 is stacked into flower-like spheres with size around 2–10 μm; with the formation of CDs, the size of MoS2 rapidly decreases to less than 1 μm and the CDs are evenly distributed on its surface with mass ratio of 40.2% (CDs in CDs/MoS2). Subsequently, the CDs/MoS2 were used as reinforcing fillers for natural rubber (NR) latex. The results of mechanical properties show that tear strength, tensile strength, modulus, and elongation at break are increased by the addition of CDs/MoS2 in a very lower loading, and the maximum increment ratio is 45.6% and 12.1% when compared to NR-0; the dynamic mechanical analysis and cross-link density results indicated that the CDs/MoS2 can simultaneously improve rigidity and elasticity of NR. The thermal stability results suggest that the CDs/MoS2 shows positive effects on thermal stability of NR. [ABSTRACT FROM AUTHOR]

Two series based on poly(propylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PPF-b-F-PTMO) containing carbon and mineral nanofillers that differ in shape (1D and 2D) were synthesized via in situ polymerization. The influence of the addition of the 1D-type nanoparticle, i.e., carbon nanofibers (CNFs) and halloysite nanotubes (HNTs), and the so-called 2D-type, i.e., graphene nanoplatelets (GNPs) and organoclay (C20A), on the properties of a biobased block copolymer was analyzed. The dispersion of nanoadditives in the nanocomposites was determined using a scanning electron microscope (SEM). The thermal properties were studied employing differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The introduction of nanoparticles increased the crystallinity (Xc) and the mean values of tensile modulus (E) of the bionanocomposites. In turn, one observed that the decrease in the limited viscosity number (LVN) was visible along with incorporating nanoadditives. The synthesized polymer bionanocomposites reveal the mechanical properties of elastomers during mechanical testing. Moreover, the good processability of the obtained materials by injection molding combined with the comprehensive ability to change mechanical and thermal properties of PPF-b-F-PTMO by tailoring the type and content of the nanofillers can indicate their possible applications in packaging, automotive, sports, construction, and many other industries. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) with their exceptional properties have the potential to revolutionize the field of electrochemistry and pave the way for new and exciting applications. MOFs is an excellent choice as an active electrocatalyst component in the fabrication of electrochemical sensors. Here, bimetallic NiCo-MOFs, monometallic Ni-MOFs, and Co-MOFs were fabricated to modify the carbon paste electrode. Moreover, the ratio between Co and Ni within the bimetallic MOFs was optimized. Our aim in this work is to synthesize different compositions from bimetallic MOFs and systematically compare their catalytic activity with mono-metallic MOFs on paracetamol. The structure and properties of the 2D NiCo-MOFs were characterized by scanning electron microscope, X-ray photoelectron spectroscopy, Fourier transform infrared, and electrochemical method. Bimetallic Ni0.75Co0.25-MOFs modified carbon paste sensor displayed the optimum sensing performance for the electrochemical detection of paracetamol. A linear response over the range 6.00 × 10− 7 to 1.00 × 10− 4 M with a detection limit of 2.10 × 10− 8 M was obtained. The proposed method was applied to detect paracetamol in spiked human plasma and to determine paracetamol in the presence of its major toxic impurity, p-aminophenol. These findings suggest the considerable potential use of the newly developed sensor as a point-of-care tool for detecting paracetamol and p-aminophenol in the future. [ABSTRACT FROM AUTHOR]

This work describes how to easily make NiO hollow sphere composites using waste sugarcane bagasse for use in supercapacitor applications. NiO hollow spheres (NOHSs) nanomaterialis effectively synthesized through the nano carbon sphere (CS) template. A core-shell structure was created on the carbon sphere's surface by NiO nanoparticles that were several nanometers in size. The structural and morphological of the synthesized materials were investigated by X-ray diffraction (XRD) and Scanning electron microscope (SEM). The energy-dispersive X-ray spectroscopy (EDS) was used to confirm the presence of the elements in NOHS. The electrochemical behaviour of hierarchical CSs and NOHSs electrode was examined through cyclic voltammetry (CV), Galvanostatic charge/discharge (SC) and electrochemical impedance spectroscopy (EIS). In GCD analysis, NOHSs electrode showed a concentrated specific capacitance (Csp) of 913.79 F/g at 5 A/g current density. The porous conductive carbon with macro pores that speeds up the transit of electron and electrolyte ions causes noticeably better capacitive behavior. [ABSTRACT FROM AUTHOR]

Dilobocondyla (Formicidae: Myrmicinae) is an uncommon and rare ant genus with only 21 species and one subspecies worldwide. The distribution of this genus is confined to the Oriental and Indo-Australian regions and reported from the Philippines, Vietnam, Indonesia, Borneo, Singapore, Malaysia, Sri Lanka, India, China, Australia and New Guinea. There is limited information about the species and some are only known from a single specimen. The characters of all the species are comprehensively compared and presented. From India, two species of Dilobocondyla, namely D. bangalorica from Karnataka and D. gasteroreticulata from Uttarakhand, Himachal Pradesh, and Sikkim have been reported. We observed D. gasteroreticulata in the campus of Gauhati University, Assam solitarily foraging on the tree trunk of Delonix regia, Mangifera indica, Monoon longifolium. Dilobocondyla may have preference for specific plants as we noticed D. gasteroreticulata on three plant species while D. bangalorica earlier reported to be present on Plumeria sp. We collected 8 specimens and identified them as D. gasteroreticulata following the taxonomic keys and morphological studies using a stereo zoom microscope and scanning electron micrographs. Assam is a part of the Eastern Himalayan biodiversity hotspot where the presence of D. gasteroreticulata is the first report from this state. The other three states where the species exist are also part of the Himalayas region. Besides, the species has recently reported from China. The geographical and climatic conditions of the regions and physiological and evolutionary adaptations of the inhabitant species influence its confined distribution which demands further investigations. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is a rapidly prevailing disease throughout the world that poses boundless risk factors linked to several health problems. Vildagliptin is the standard dipeptidyl peptidase-4 (DPP-4) inhibitor type of medication that is used for the treatment of diabetes anti-hyperglycemic agent (anti-diabetic drug). The current study aimed to synthesize vildagliptin-loaded ZnO NPs for enhanced efficacy in terms of increased retention time minimizing side effects and increased hypoglycemic effects. Herein, Zinc Oxide (ZnO) nanoparticles (NPs) were constructed by precipitation method then the drug vildagliptin was loaded and drug loading efficiency was estimated by the HPLC method. X-ray diffraction analysis (XRD), UV–vis spectroscopy, FT-IR, scanning electron microscope (SEM), and EDX analysis were performed for the characterization of synthesized vildagliptin-loaded ZnO NPs. The UV–visible spectrum shows a distinct peak at 363 nm which confirms the creation of ZnO NPs and SEM showed mono-dispersed sphere-shaped NPs. EDX analysis shows the presence of desired elements along with the elemental composition. The physio-sorption studies, which used adsorption isotherms to assess adsorption capabilities, found that the Freundlich isotherm model explains the data very well and fits best. The maximum adsorption efficiency of 58.83% was obtained. Further, In vitro, anti-diabetic activity was evaluated by determining the α-amylase and DPP IV inhibition activity of the product formed. The formulation gave maximum inhibition of 82.06% and 94.73% of α-amylase and DPP IV respectively. While at 1000 µg/ml concentration with IC50 values of 24.11 μg/per ml and 42.94 μg/ml. The inhibition of α-amylase can be ascribed to the interactive effect of ZnO NPs and vildagliptin. [ABSTRACT FROM AUTHOR]

Greener fabrication of nanostructures has received remarkable attention due to their sustainability, cost-effectiveness, simplicity, and eco-friendliness. Opuntia ficus-indica-derived mucilage has not been exposed well to fabricate nanostructures. Thus, in this present investigation, we successfully synthesized tungsten trioxide (WO3) nanostructures using Opuntia ficus-indica-derived mucilage as bio-templates because it is more economical and environmentally friendly. Also, the fabricated WO3 nanostructures cytotoxic features and their photothermal effects were studied. The WO3 nanostructures were investigated using diverse analytical instruments: X-ray diffractometer (XRD), scanning electron microscope and, transmission electron microscope. Based on the structural and morphological characteristics of the WO3 nanostructures, they have sphere-like morphologies with diameters of 100 - 200 nm. As revealed by XRD, monoclinic crystalline WO3 nanostructures were formed. In vitro assays were used to assess the effect of WO3 nanostructures on cell viability and morphological features of cells. Based on in vitro assays, fabricated WO3 nanostructures showed slightly toxic behaviour in a human breast cancer cell line (MCF-7 cells). In contrast, after exposure to NIR lasers, the viability of WO3 nanostructures treated cells decreased significantly. Because the WO3 nanostructures have an excellent photothermal effect, which triggers cell death in cancer cells. Thus, the fabricated WO3 nanostructures can be used as a photothermal agent for cancer therapy [ABSTRACT FROM AUTHOR]

Flawed rocks subjected to hydrostatic confinements in deep underground engineering are vulnerable to dynamic disturbances. Understanding the dynamic mechanical responses and fracture characteristics of flawed rocks is crucial for the design and construction safety of deep underground structures. In this research, using a triaxial split Hopkinson pressure bar device, the dynamic triaxial compression tests are performed on multi-flawed sandstone specimens containing different flaw angles and distances. The experimental results revealed the influence of the flaw angle, flaw distance, and hydrostatic confining pressure on the dynamic strength characteristics, deformation properties, failure modes and fracture mechanisms of rocks. Both the dynamic strength and elastic modulus increase with rising hydrostatic confining pressure, while the dynamic strength depicts a positive correlation with strain rate. The dynamic strength fluctuates zigzag with the flaw angle, and decreases first and then increases slightly with flaw distances. Specimens with different flaw angles all demonstrate conjugated "X" shape failure, while the single shear band failure is shown for certain flaw distances. Seven crack categories are identified based on the basis of different trajectories and the fracture characteristics of new cracks are analyzed in multiscale perspective. The scanning electron microscope observation indicates numerous shear traces on the fracture surface while brittle fracture features are relatively few. Furthermore, the fracture surface roughness is quantified by the 3D scanning technique and fractal dimension. Rocks containing higher flaw distance or under higher hydrostatic confining pressure are featured by lower fractal dimension and smoother fracture surfaces. Highlights: Dynamic impacting tests on hydrostatically confined rocks containing multiple flaws were conducted. The influence of hydrostatic confining pressure and flaw configuration on the dynamic strength, deformation properties, and failure characteristics of rocks were investigated. The fracture mechanism of flawed rocks under hydrostatic confinements by the scanning electron microscope and 3D scanning technique was analyzed. [ABSTRACT FROM AUTHOR]

As a typical toxic substance in environmental water, phenolic pollutants, represented by p-nitrophenol, pose a great threat to the ecological environment. In this study, using WCl6 and oxalic acid as raw materials, a novel p-nitrophenol (PNP) sensor fabricated by tungsten phosphide (WP) nano-particles, has been successfully designed and constructed, which expanded the application of WP nano-materials in the field of electroanalysis. The successful synthesis of WP has been confirmed by a series of characterization techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The electrochemical experiments were all carried out in phosphate buffer solution with the pH of 6.5. The WP nano-particles can electrocatalytically oxidize PNP to produce a current for the detection of PNP. The reaction sites of PNP are predicted by Gaussian 09 and Multiwfn. Prominent performance has been recorded for PNP sensor, attaining a wide linear range from 10.00 to 6500.00 μM, a low detection limit of 1.59 μM with the reliable selectivity, repeatability, and stability. Gratifyingly, the prepared sensor could satisfy the requirements of PNP determination in actual environmental water, such as tap water and rainwater. [ABSTRACT FROM AUTHOR]

The damage mechanisms of ductile fracture under shear loading of an aluminum alloy 2198T8R were studied using flat thin-sheet samples. One sample was loaded until 85% of the failure displacement and then unloaded, and another one was loaded up to failure. To overcome the inherent shortcomings of nanotomography concerning the investigation of flat samples, synchrotron nano-laminography was applied to the pre-loaded sample and provided structural information down to the nanometer scale, allowing ductile damage nucleation and evolution to be studied. The damage features, including flat cracks and intermetallic particle-related damage, were visualized in 3D from the highly-deformed shear band region. Using nano-laminography, no nano-voids were found. The damaged shear ligament was also observed after polishing via destructive correlative scanning electron microscope (SEM) and electron back-scatter diffraction (EBSD) which suggests that the detrimental flat cracks were both intergranular and transgranular. The flat cracks were related to highly-deformed bands. No nano-voids could be found using SEM analysis. Fractography on the second broken sample revealed that the flat cracks contained hardly observable nanometer-sized dimples. The final coalescence region was covered by sub-micrometer-sized dimples, inside which dispersoid particles were present. The fact that no nano-void was found for the pre-deformed sample implies that the nucleation, growth and coalescence of these sub-micrometer-sized voids occur at late stages of the loading history. [ABSTRACT FROM AUTHOR]

La1 –xSrxCoO3 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) were prepared by the alginic acid sol–gel route and characterized by thermo gravimetric analysis (TGA), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques. The electrocatalytic activity of fabricated oxide electrodes (Ni/oxide) was studied for oxygen evolution reaction (OER) in an alkaline medium. The cyclic voltammetry of oxide electrodes shows a pair of redox couple at anodic peak potential (Epa) = 400 ± 6 mV and cathodic peak potential (Epc) = 296 ± 8 mV. The observed values of electrode kinetic parameters such as the Tafel slope (b) lie between 91 and 126 mV dec–1 and current density (j) lie between 17.0–73.1 mA cm–2 at 0.85 V. The Sr-substitution in lanthanum cobaltate matrix improve electrocatalytic activity for OER in an alkaline medium and maximum improvement was observed in the case of 0.4 mol Sr-substituted oxide. The order of reaction (p) with respect to the concentration of [OH–] is found unity and the highly negative value of entropy of the reaction indicated the oxygen evolution follows the same mechanism and involves the adsorption of the reaction intermediate. [ABSTRACT FROM AUTHOR]

In this paper, the silicone rubber (SR)/thermoplastic polyurethane (TPU) composites and its compatibilizers were studied by molecule dynamics simulation and experiment. Three compatibilizers, fluorosilicone rubber (FSR), dendritic hydroxyl-terminated silicone oil (DHSO), and fluorinated modified tetraethyl orthosilicate grafted silicone rubber (FTEOS-g-SR) were introduced into the SR/TPU composites. The simulation results showed that the cohesion density of pure SR was 3.072 × 108 J/m3, the solubility parameter was 17.504 (J/cm3)0.5, the Young's modulus was 4.0139 GPa, the shear modulus was 1.4493 GPa, and the bulk modulus was 5.8061 GPa. Moreover, the cohesion density of SR/TPU/FSR and SR/TPU/DHSO increased to 4.693 × 108 and 3.459 × 108 J/m3, solubility parameter increased to 21.662 and 18.597 (J/cm3)0.5, the Young's modulus increased to 6.6399 and 6.0020 GPa, shear modulus increased to 2.4377 and 2.2060 GPa, and bulk modulus increased to 8.0148 and 7.1653 GPa, respectively. However, the cohesion density, solubility, and young's modulus of SR/TPU/FTEOS-g-SR decreased to 2.617 × 108 J/m3, 16.174 (J/cm3)0.5, 3.872 GPa, 1.7510 Gpa, and 1.6365 GPa. These results demonstrated that both FSR and DHSO can improve the mechanical properties of the SR/TPU composites, while the FTEOS-g-SR reduced their mechanical properties. The compatibility and mechanical properties of SR/TPU composites modified by FSR and DHSO were verified and compared. The factors such as blending temperature, blending ratio, and TPU types of SR/TPU composites were considered. Compared to composites cured at 185 °C, those cured at 175 °C exhibited better mechanical properties. The dynamically vulcanized SR/TPU (3:7, mass ratio) materials showed superior tensile strength and elongation at break when compared to the SR/TPU (5:5, mass ratio) composites. Moreover, the polyether type of TPU was found to be more favorable than the polyester type for obtaining a blended composite with good tensile properties. The experimental results demonstrated that both compatibilizers contributed to improving the mechanical properties of the composites to a certain extent. The scanning electron microscope (SEM) test revealed that FSR enhanced the dispersion of SR in the TPU matrix. Additionally, charge distribution simulation analysis indicated the presence of abundant intermolecular hydrogen bonds between FSR and TPU, which played a significant role in the excellent compatibility and mechanical properties observed in this blend system. [ABSTRACT FROM AUTHOR]

The progress in developing biomaterials for cartilage replacement is still not sufficient, and researchers face the challenge of developing materials that can imitate the physical, chemical, and mechanobiological characteristics of natural cartilage. In this research, the graphene oxide was blended with polyvinyl alcohol/chitosan composite to fabricate composite hydrogels (PVA/Chitosan/GO) using different concentrations of graphene oxide (0, 0.75, 1.5, 2.25, and 3 wt%). The images taken with a scanning electron microscope (SEM) displayed that adding graphene oxide affected the hydrogel structure by reducing the porosity. The composite hydrogel with 3 wt% graphene oxide exhibited the highest compressive strength of 2.15 MPa, and the storage modulus was significantly greater than that of polyvinyl alcohol/chitosan, which satisfied the application requirements. Furthermore, the composite hydrogels displayed excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus bacterial species. They exhibited in vitro cell viability against L929 mouse fibroblasts, which presents the possibility of using composite hydrogel for cartilage regeneration. [ABSTRACT FROM AUTHOR]

Here, ultrasonic spray pyrolysis method (USP) was utilized to produce pure and silver doped copper oxide nanostructures on glass substrates. Thereafter, several characterization techniques were conducted on the grown samples to delve into their morphological, structural, electrochemical, and optical aspects. The mentioned analyses were carried out by performing x-ray photoelectron spectroscopy, scanning electron microscope, X-ray diffraction, electrochemical impedance spectroscopy, galvostatic charge-discharge, cyclic voltammetry, and UV–visible spectroscopy measurements. Thus, the impact of silver impurity doping on the relevant aspects of host material were recorded as well as the features of unspoiled copper oxide films. Accordingly, the samples, as indicated by X-ray diffraction results, possessed (002) preferential plane orientation of copper oxide material along with the crystallite sizes ranging from 52.52 nm to 75.02 nm due to the imperfections caused by the silver doping. The scanning electron microscope images exhibited that the silver doping did not form significant modifications in the host material morphology where nanowire-like structures observed. The presence of the suggested materials in the films was verified by the x-ray photoelectron spectroscopy. Also, the UV–visible spectroscopy measurements detected that optical absorbance edge and bandgap energy values red shifted as a result of the impurity doping. The electrochemical supercapacitors performances of the silver doped copper oxide nanostructured thin films were inspected by using the GCD, EIS, and CV. The silver doped copper oxide films demonstrated a specific capacitance value of 66 F/g at a current density of 1 A/g in 1 M KOH electrolyte. From Nyquist plot, Rs, Rcor, Rpo, Ccor and Cc were obtained as 2.327 × 103 Ω.cm2, 43.63 × 103 Ω.cm2, 4.580 × 103 Ω.cm2, 111.5 × 10-6 S*s^a. cm-2 and 101.1 × 10-6 S*s^a. cm-2, respectively. The results indicated that the electrochemically synthesized the silver doped copper oxide electrodes can be obtained and developed as an alternative electrode material for supercapacitors (SCs). [ABSTRACT FROM AUTHOR]

The catalytic performance of Hβ zeolite treated with different concentration of NaOH on the alkylation of tert-butanol with phenol was studied. The effect of NaOH concentration on the crystallinity, morphology, textural property and acidity of Hβ zeolite was studied by X-ray diffraction (XRD), scanning electron microscope characterization (SEM), N2 adsorption–desorption, Fourier transform infrared spectroscopy (FT-IR) and pyridine adsorption infrared spectra (Py-IR) techniques. A certain concentration of NaOH treatment can regulate the pore structure of Hβ zeolite and remove part of framework aluminum and framework silicon, thus achieving the purpose of regulating the pore structure and acidity of the catalyst. Though lower Bronsted to Lewis acid amount ratio when treated NaOH concentrations were 0.15 mol/L, leading to the increasing of selectivity to 4-TBP. The Hβ-0.2 M showed the high selectivity of 90.21% for synthesis of 4-tert-butyl-phenol (4-TBP), compared with the unmodified parent zeolite, the selectivity of 4-TBP improved 16.7%. [ABSTRACT FROM AUTHOR]

A series of CZ-xS catalysts for deNO(x) were prepared by sol–gel method. The effects of preparation methods and the amount of sulfuric acid in the sol–gel preparation process on the performance of catalyst were investigated by means of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), N2 adsorption–desorption, NH3-temperature programmed desorption (NH3-TPD), H2-temperature-programmed (H2-TPR) and Scanning electron microscope/Energy Dispersive Spectrometer (SEM/EDS). The results showed that when the mass ratio of SO42−/ZrO2 (CZ-0.4S catalyst) was 0.4, the catalytic performance of the catalyst prepared by sol–gel method was greatly improved compared with the sample prepared by coprecipitation + impregnation method. When the space velocity was 220,000 h−1 and the reaction temperature was in range of 290–500 °C, the NO conversion was higher than 90% on CZ-0.4S catalyst. Its excellent denitrification performance was attributed to its larger acidity, higher Ce3+ content, more surface adsorbed oxygen and larger specific surface area. [ABSTRACT FROM AUTHOR]

Nanostructured duplex stainless steel (DSS) was prepared using mechanical alloying (MA) and spark plasma sintering (SPS). The ball milling was performed under nitrogen atmosphere. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to identify the phases and carry out morphological investigations, respectively. XRD spectra revealed that ferrite phase formation dominated during the initial stages and austenite phase emerged after several hours of ball milling. Lattice parameter calculations showed a decrease in lattice parameter up to 5 h and later increased at 10 h of milling. A decrease in crystallite size was observed up to 10 h of milling. SPS was performed in vacuum at an optimized temp. of 1000 °C for a fixed holding time of 10 min, heating rate of 100 °C/min, cooling rate of 200 °C/min and under an applied pressure of 50 MPa. The electrochemical performance of DSS alloys was examined using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that alloy Fe-18Cr-3Mn-1Mo-1Si-0, 22N-5Ni (wt.%), has the highest corrosion resistance among the designed alloys. [ABSTRACT FROM AUTHOR]

Aluminum alloy forms a protective layer of aluminum oxide when exposed to air, which gives it corrosion resistance. But, the layer can be easily damaged, causing metal corrosion. The hard anodizing method is used to solve this issue. Determining the appropriate anodizing parameters, including current density, process time, and electrolyte concentration, is crucial for attaining the desired thickness and hardness of the anodized layer. An experimental design approach utilizing the response surface method (RSM) was employed to investigate the effects of these variables. Quadratic models were presented to predict the hardness and thickness of the layer with an average error of 2.84% and 3.89%, respectively. The models were verified through analysis of variance (ANOVA) to assess the effect of each parameter and their interactions. Oxalic acid concentration, the interaction between process time and oxalic acid concentration, and the square of current density and process time have a significant impact on hardness. Layer thickness is mainly influenced by current density, process time, and the interaction between process time and oxalic acid concentration. Optimization results show that a current density of 1.19 A / dm 2 , a process time of 160 min, sulfuric and oxalic acid concentrations of 26.25 g r / l i t and 36.88 g r / l i t , respectively, leads to hardness of 434 HV and thickness of 93.6 µm. A scanning electron microscope (SEM) image under optimal conditions shows that aluminum porous arrays created by an anodizing process in mixed sulfuric acid and oxalic acid electrolyte, with a hexagonal shape observed across a wide range of grain domains. [ABSTRACT FROM AUTHOR]

We have found that the unique particle properties of fly ash can be applied to the modification of shear thickening fluid. In this paper, rheological properties and microscopic thickening mechanism of fly ash/silicon-based shear thickening fluid (subsequently abbreviated as FA/SiO2-STF) are studied. Ultrasonic technology and mechanical stirring method were used to prepare FA/SiO2-STF with different mass fractions of fly ash, and then rheometer was used to carry out steady-state rheological testing for FA/SiO2-STF, and 4%FA/SiO2-STF dynamic rheological test and temperature sensitivity testing, respectively. The thickening mechanism of FA/SiO2-STF was analyzed by scanning electron microscope. The rheological test results show that the FA/SiO2-STF with 4% fly ash content exhibits remarkable shear thickening effect. Finally, the relationship between the viscosity and shear rate of FA/SiO2-STF is numerically described by a mathematical model, which can accurately reflect the viscosity thickening effect. [ABSTRACT FROM AUTHOR]

Objectives: In-vitro studies were performed on dentin of extracted human molars to investigate the effectiveness of 9.3 μm CO2 laser irradiation to occlude dentinal tubules. The observed occlusion of dentinal tubules with the irradiation was compared with application of three reagents: 2% Sodium Fluoride gel, an aqueous solution of hydroxyapatite nanoparticles and an equal mix of the two. We show that 9.3 μm CO2 laser irradiation occludes dentinal tubules, and the use of laser irradiation produces better occlusion of the opened tubules compared to the use of topical reagents. Methods: Nine extracted and cleaned human molars were cut to obtain dentin disks of thickness of 3–5 mm. Each disc was divided into four quarters, and each quarter served as two samples corresponding to irradiated and non-irradiated group counterparts. Five disks were used to study the effect of various laser irradiation energies on the dentinal tubules to find a good pulse fluence for occlusion of the dentinal tubules, and four disks were used for studying the effects of reagents and irradiation at the pulse fluences found in the first part of the study. The samples were irradiated with a beam diameter of 1 mm (1/e2) at 15 Hz pulse repetition rate, scanned automatically using a set of scanning mirrors. Samples were imaged using Scanning Electron Microscope (SEM) which were processed to determine tubule diameter. Safety of the irradiation treatment was investigated on 6 samples by measuring pulpal temperature rise. The effect of three topical reagents corresponding to 2% Sodium Fluoride gel (F), Hydroxyapatite nanoparticles (HA) and an equal mix of F and HA (HAF) on dentinal tubule occlusion was evaluated and compared with the laser irradiation. Results: In all examined cases, laser irradiation at a fluence of 0.81 J/cm2 resulted in a temperature increase less than 3 °C which is safe, and no surface cracking was observed. There is a threshold pulse fluence of 0.27 J/cm2 above which, laser produced surface melting. At a pulse fluence of 0.81 J/cm2 a layer of recast of melted dentin was formed. Under this layer, peritubular dentin melting and occluding of the dentinal tubules was observed. Application of either F or HA or HAF did not produce visible occlusion effect on open tubules after washing and microbrushing with excess distilled water. Conclusions: 9.3 μm CO2 laser irradiation on extracted human molar dentin at pulse fluence of 0.81 J./cm2 resulted in tubule area reduction by 97% without rising pulpal temperatures to unsafe levels. [ABSTRACT FROM AUTHOR]