Average Size Distribution Research Articles

Dislocation assisted coarsening of coherent precipitates: a phase field study

ABSTRACT Coarsening of precipitates in coherent systems is influenced by the elastic fields of the precipitates and the interfacial curvature. It is also known that if precipitates are connected by dislocations, coarsening is affected by the elastic fields of the dislocations and the pipe diffusivity. Although there is experimental evidence of accelerated coarsening in the presence of dislocations, these studies do not capture the effect of the elastic fields. There exist generic theoretical models that can predict the average sizes and size distributions of coarsening precipitates considering the coherency-related elastic stress fields. In this paper, we use a phase field model to study the coarsening of precipitates connected by dislocations, incorporating its elastic fields and pipe diffusivity. Specifically, we study the effects of misfit strain, elastic moduli mismatch, faster pipe mobility and the elastic fields of the dislocation on the morphology and kinetics of the coarsening precipitates. The dilatational component, associated with the edge character of the dislocations interacts with the precipitates in an elastically homogeneous system. In an elastically inhomogeneous system, the deviatoric elastic fields also interact with the precipitates influencing the morphology and kinetics of coarsening precipitates. The kinetics of coarsening is different as well, with hard precipitates coarsening faster as compared to soft precipitates, when connected by dislocations. Further, we note that the modified Gibbs–Thomson equation, which was originally derived for an isolated precipitate in an infinite matrix, is also applicable for coarsening precipitates at close proximity.

Hot Uniaxial Pressing and Pressureless Sintering of AlCrCuFeMnNi Complex Concentrated Alloy-A Comparative Study.

External pressure is often applied during sintering to obtain materials with improved properties. For complex concentrated alloys (CCAs), this processing step is commonly performed in vacuum. However, this can promote the evaporation of elements and increase the oxide content, thereby degrading the properties of the alloy. In this study, we compared the microstructures and properties of AlCrCuFeMnNi CCA samples obtained by hot uniaxial pressing sintering (HPS) and pressureless sintering (PLS) using a helium atmosphere purified by an oxygen getter system. The powders were prepared from mixtures of CrFeMn, AlNi and Cu and sintered by HPS at 900 °C for 1 h with an applied pressure of 30 MPa and by PLS at 1050 °C for 1 h. The samples were characterised using X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattering diffraction, density measurements and hardness tests. It was found that the oxygen getter system promoted oxygen partial pressure values at sintering temperatures similar to those of a mixture of 90% helium and 10% hydrogen. The HPS allowed us to obtain almost fully dense samples with a smaller average grain size and finer distribution of aluminium oxides than PLS. These differences increased the hardness of the samples sintered under pressure.

An H3O-alunite method for production of smelter grade alumina from an ammonium alum solution after high-pressure acid leaching of coal fly ash

Precipitation of H3O-alunite from an ammonium alum solution using boehmite as a seed was studied. The ammonium alum solution was obtained after high-pressure leaching of mullite-type coal fly ash (CFA) with a mixture of 7.5 M H2SO4 + 40% NH4HSO4 at 200 °C. Fe(III) was extracted from the ammonium alum solution by ion exchange sorption using the Purolite S957 resin. Effects of temperature (70–90 °C), seed boehmite (100–400 g/l), ammonium alum (60–240 g/l), and precipitation duration (2–8 h) on the Al precipitation degree were evaluated. Calcination of the precipitate at 300–950 °C to obtain alumina powder was studied next. Concentration of impurities, specific surface area, phase composition, morphology, and the average particle size distribution of alumina powders were investigated. The results show that smelter grade alumina (SGA) can be obtained at optimized parameters of precipitation and calcination.

Tuning the structural, morphological, optical, dielectric, and magnetic properties of PVA via embedding with CoFe2O4:CuO nanoparticles

Polyvinyl alcohol (PVA) embedded CoFe2O4: CuO (CC) nanocomposites (NC) were prepared by casting technique. The prepared CoFe2O4 (CFO) sample have crystallite size in the range of 20.10-29.08 nm, whereas the crystallite sizes of CuO were found in the range of 20.29-23.68 nm, respectively. TEM images revealed the spherical shape morphology of CC nanocomposite with an average particle size distribution of 15 nm. The Urbach energy of the PCC films increased from 0.44 to 2.590 eV, whereas the direct optical band gaps decreased from 5.584 to 4.345 eV, respectively. The refractive indices of the PCC films were found to be in the range of 1.9 -2.6, depending on the different models. Room Temperature-dependent saturation magnetization and coercive field for the prepared nanocomposites were found to be 0.52-1.296 (emu/g) and 1210-1340 (Oe), respectively. The uniaxial magnetic anisotropic constant of PCC films was remarkably enhanced from 0.654x103 to 3.826x103 (erg/cm3) for PCC2, PCC3, and PCC4, correspondingly. The enhanced values of dielectric and magnetic parameters of the prepared nanocomposites suggest their suitability for magnetic recording and memory systems.

Two-Dimensional X-Ray Diffraction (2D-XRD) and Micro-Computed Tomography (Micro-CT) Characterization of Additively Manufactured 316L Stainless Steel

In-depth quality assessment of 3D-printed parts is vital in determining their overall characteristics. This study focuses on the use of 2D X-Ray diffraction (2D-XRD) and X-Ray micro-computed tomography (micro-CT) techniques to evaluate the crystallography and internal defects of 316L SS parts fabricated by the powder-based direct energy deposition (DED) technique. The test samples were printed in a controlled argon environment with variable laser power and print speeds, using a customized deposition pattern to achieve a high-density print (>99%). Multiple features, including hardness, elastic modulus, porosity, crystallographic orientation, and grain morphology and size were evaluated as a function of print parameters. Micro-CT was used for in-depth internal defect analysis, revealing lack-of-fusion and gas-induced (keyhole) pores and no observable micro-cracks or inclusions in most of the printed body. Some porosity was found mostly concentrated in the initial layers of print and decreased along the build direction. 2D-XRD was used for phase analysis and grain size determination. The phase analysis revealed single phase γ-austenitic FCC phase without any detectable presence of the δ-ferrite phase. A close correlation was found between Electron Backscatter Diffraction (EBSD) and 2D-XRD results on the average size distribution and the crystallographic orientation of grains in the sample. This work demonstrates the fast and reliable as-printed crystallography analysis using 2D-XRD compared to the EBSD technique, with potential for in-line integration.

Biosynthesis of selenium nanoparticles as a potential therapeutic agent in breast cancer: G2/M arrest and apoptosis induction

The drawbacks and adverse reactions of conventional breast cancer (BC) medications have prompted researchers to seek novel therapeutic approaches. This study aimed to study the impact of biosynthesized selenium nanoparticles by yeast on breast cancer (MCF-7) cells and to find potential underlying mechanisms. Therefore, marine yeast isolates were screened for their ability to biosynthesis selenium nanoparticles (SeNPs). The most potent isolate was identified as Candida pseudojiufengensis based on 18 S rRNA gene sequencing. Incubation of cell-free extract with 0.8 mM of SeO2 for 48 h at 40°C in pH of 7.0 were optimal conditions for the biosynthesis of SeNPs. The biosynthesized SeNPs were characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS) measurements including average particle size distribution and average zeta potential. The results showed that the biosynthesized SeNPs displayed a maximum absorbance peak in the UV-Vis spectrum at 560 nm due to surface plasmon resonance. TEM image elevated spherical shape particles with an average size of 12 nm. SRB assay, flow cytometry, and other biochemical methods were employed to assess SeNPs anti-proliferative effects on MCF-7 cells. SeNPs showed superior anticancer efficacy against MCF-7 cells compared to colon (HCT-116) and liver (HepG2) cancer cells, as evidenced by lower IC50 values (19.59 µg/ml) against 36.36 µg/ml and 27.81 ±1.4 µg/ml, respectively. However, SeNPs demonstrated no cytotoxic effects against HSF cells. Moreover, treatment with SeNPs induces G2/M arrest along with triggering apoptosis in MCF-7 cells. Furthermore, MCF-7 cells treated with SeNPs showed increased oxidative stress, as indicated by observable rises in LPO and 8-OHDG, accompanied by considerable exhaustion in antioxidant enzyme activity. These findings demonstrated that Se nanoparticles synthesized from yeast have therapeutic promise in BC treatment.

Intercomparison of WRF-chem aerosol schemes during a dry Saharan dust outbreak in Southern Iberian Peninsula

The Iberian Peninsula (IP), where this study is conducted, has experienced an increase of the frequency and intensity of Saharan aerosol dust outbreaks over the latest decades, which may have an impact on its regional climate. The Weather Research and Forecasting model coupled with chemistry (WRF-chem) has been used worldwide to simulate dust outbreaks and can support the analysis of such potential impacts. However, it includes multiple alternative aerosol parameterization choices that have not been conveniently evaluated in the study region yet. Here, three of the most popular WRF-chem aerosol parameterization schemes, namely, the Goddard Chemistry Aerosol Radiation and Transport (GOCART), the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and the Modal Aerosol Dynamics Model for Europe (MADE) schemes, are inter-compared during a strong and dry dust outbreak on July 2021 in southern IP. The results show that the three schemes predict qualitatively similar dust intrusion patterns that are consistent with ground observations and have inter-model dust loading differences smaller than 4%. However, their average dust size distributions differ notably. While GOCART is reasonably consistent with observations, MOSAIC underpredicts the amount of dust particles with sub-micron diameters and overpredicts that of large particles and MADE does the opposite. This is found to have a strong detrimental impact on the prediction performance of dust optical properties in MOSAIC and MADE, which is related, at least partially, with issues in the required inter-sectional redistribution of dust parameters during the dust emission and calculation of optical properties. Overall, GOCART generally appears a better choice for strong and dry dust outbreak events in southern IP. It remains to be evaluated during wet dust outbreaks, which is a work underway.

Effect of Hexamethylenetetramine concentration on the structural, morphological, optical and bactericidal action of Eu-doped TiO2 quantum dots derived through wet chemical method

Recently, it has been established that bacteria are quickly developing resistance to traditional antibiotics; as a result, one of the most significant challenges facing the healthcare sector is treating illnesses linked to bacterial infections. In this work, we used a simple wet chemical approach to easily prepare pure TiO2 and Eu-doped TiO2 quantum dots (QDs) with different hexamethylenetetramine (HMT) concentrations: 0.1, 0.15, and 0.2 M. As indicated by XRD results, the pure TiO2 possesses the tetragonal anatase phase, while the Eu-doped TiO2 samples prepared with the support of HMT content during sample synthesis promotes the amorphous phase. The Eu-doped TiO2 sample prepared at 0.1 M HMT has an almost uniform distribution of ultra-fine QDs, with an average particle size distribution of 2.05 ± 0.17 nm, according to the TEM image. The Eu 3d core level doublet at 1134.29 and 1164.21 eV, which correspond to Eu3+3d5/2 and Eu3+3d3/2, respectively, is displayed in the XPS data for the sample prepared at 0.1 M HMT. Based on the findings of the Tauc plot, the sample prepared at 0.2 M HMT is found to have a larger optical band gap than the pure TiO2 and Eu-doped TiO2 samples prepared at different HMTA concentrations. According to antibacterial tests, the zone of inhibition for E. coli increases from 7 ± 0.55 to 12 ± 0.60 when the concentration of the Eu-doped TiO2 sample prepared at 0.15 M HMT is increased from 100 to 300 µg/mL. In the field of biomedical application, this enhanced antibacterial activity of Eu-doped TiO2 QDs can be utilized to create a potent medication for bacterial resistance.

The effect of hydrothermal conditions on surface properties of synthesized nano SBA-15 using sodium silicate

A successful synthesis of mesoporous Santa Barbara amorphous (SBA-15) with nanoparticle size was attempted using prepared sodium silicate from Iraqi high silica sand. EO20PO70EO20 copolymer was used as a template at highly acidic conditions (pH < 2). The effect of crystallization temperature of (100, 110, 120, and 130 0C), and crystallization time of (24, 48, 72, and 120 h) on surface properties was studied. The experiments were characterized using XRD, FTIR, AFM, BET, and FESEM. The XRD and FTIR tests represent amorphous SBA-15 without any impurities. Decreasing average particle size distribution increased the surface area, and decreased the porosity (pore volume, and pore size) in all experiments. The texture properties were surface area of 210-756 cm2/g, volume pore of 0.28-0.7 cm3/g, and pore size of 1.94-13.45 nm. The optimum result of surface area was achieved at hydrothermal conditions of 110 0C, and 24 h, while optimum results of pore volume, and pore size were achieved at hydrothermal conditions of 100 0C, and 120 h. Semi-spherical shape of particles appeared at hydrothermal conditions of 120 0C and 24 h. This morphology was transferred to small rods at 130 0C, and to semi-platelets at 120 h.

Effect of Ag doping on the structural, morphological, optical and antibacterial activity of ZnS nanoparticles

In this study Ag-doped ZnS nanostructures for antibacterial activity were prepared by means of a facile wet-chemical method. XRD study reveals a decrease in the intensity of XRD peaks and the presence of an additional peak for silver which further affirms the incorporation of silver ions in ZnS matrix. The synthesized 1% Ag-doped ZnS nanostructures have the average particle size distribution of 16.45 ± 0.13 nm based on the TEM image. The antimicrobial activity of pure ZnS and Ag-doped ZnS were evaluated against Staphylococcus aureus and Escherichia coli. The results show that the bacterial inhibition was enhanced due to the doping of Ag into ZnS matrix in contrast to ZnS. This results obtained from the antibacterial study could be capitalized to be administered as a potent antibacterial drug for biomedical application.

Green synthesis of copper oxide nanoparticles using Ficus racemosa leaf extract and investigation of its antibacterial properties

ABSTRACT The present work reports a one-pot green synthesis of copper oxide nanoparticles (CuO NPs) using Ficus racemosa leaf extract via a green chemistry approach without using any harsh chemical reagents. The crystalline and single-phase CuO NPs were analysed via XRD. DLS revealed the average particle size distribution, and zeta potential was used for the evaluation of surface charge. Optical properties were determined at 530 nm through UV–Vis spectroscopy with a broad peak in the range from 500 to 590 nm. Different functional groups in the leaf extract containing flavonoids and polyphenols as reducing agents responsible for the synthesis of CuO NPs were verified through FTIR. The FESEM images revealed the average particle size in the range from 30 to 300 nm with a spherical morphology, and EDS was used for the quantitative elemental analysis. The strong bacterial inhibition tendency of CuO NPs against 12 bacterial strains including Bacillus cereus, Campylobacter jejuni, Bacillus subtilis, Clostridium perfringens, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Shigella dysenteriae, Listeria monocytogenes, Helicobacter pylori, and Salmonella typhi was observed with MIC values between 60 and 1000 µg/mL. The findings suggest that the synthesis of CuO NPs via green chemistry can serve as a potential substitute for traditional multi-step chemical synthetic routes.

Characterization of PM2.5 emissions from on-road vehicles in the tunnel of a major Middle Eastern city

Traffic emissions are an important source of air pollution worldwide, but in the Middle East, this problem is exacerbated by weak or no enforcement of emission regulations. Comprehensive measurements of fine PM emission factors (EFs) from road transport in the region have not yet been conducted, but such data are necessary for quantitative assessments of the health impact of transport emissions in the region. To address this need, PM2.5 samples collected inside the Salim Slam tunnel in Beirut, Lebanon were analyzed for carbonaceous matter (organic carbon (OC) and elemental carbon (EC)), water-soluble ions, elements, and selected organic compounds. The OC/EC ratio was 1.8 for the total fleet and 2.6 for light-duty vehicles (LDV), in agreement with the dominant proportion of gasoline LDV in the Lebanese fleet. A Cu/Sb ratio of 4.2 ± 0.1 was observed, offering a valuable metric for detecting brake wear emissions in subsequent studies conducted in the region. The EFs of carbonaceous matter, elements and ions generally varied by a factor 0.1 and 10 in comparison to literature values, while those for alkanes and polycyclic aromatic hydrocarbons were similar to the upper values previously reported. The average number size distribution was characterized by a single mode around 35 nm. The particles number EF (for diameters between 10 and 480 nm) was within the range of 1014-1015 particles per kg of fuel. The chemical mass balance model showed an average contribution to EF of 62% from non-exhaust sources. This study highlights the need for more enforceable stringent vehicular regulations because of the local practices (i.e., removal of catalyst) and some EF values are very high compared to other studies/countries.

Biodegradable Acid-Based Fe2MnO4 Nanoparticles for Water Remediation.

This study demonstrated the synthesis of Fe2MnO4 modified by citric acid, a biodegradable acid, using a simple co-precipitation method. Characterization was performed using qualitative analysis techniques such as Fourier-transformed infrared spectroscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, selected-area electron diffraction, N2 adsorption-desorption, and zero-point charge. The prepared nanoparticles had a rough and porous surface, and contained oxygenous (-OH, -COOH, etc.) functional groups. The specific surface area and average pore size distribution were 83 m2/g and 5.17 nm, respectively. Net zero charge on the surface of the prepared nanoparticles was observed at pH 7.5. The prepared nanoparticles were used as an adsorbent to remove methylene blue dye from water under various conditions. Using small amounts of the adsorbent (2.0 g/L), even a high concentration of MB dye (60 mg/L) could be reduced by about ~58%. Exothermic, spontaneous, feasible, and monolayer adsorption was identified based on thermodynamics and isotherm analysis. Reusability testing verified the stability of the adsorbent and found that the reused adsorbent performed well for up to three thermal cycles. Comparative analysis revealed that the modified adsorbent outperformed previously reported adsorbents and unmodified Fe2MnO4 in terms of its partition coefficient and equilibrium adsorption capacity under different experimental conditions.

Bioactive zinc nanomaterials synthesized from Crotalaria Pallida leaf extract using hydrothermal method

In the present-day nanotechnology is popular in all the fields of technology. The extended application of nanotechnology was utilized in drug delivery, dye absorption, wastewater removal, and in environmental pollutant eradication. However, it is important to follow green synthesis of nanomaterials for safety purposes. In the present study, the zinc nanomaterial was synthesized using a hydrothermal method from Crotalaria pallida leaf extract, which shows that the average size distribution of zinc nanomaterials that have been synthesized was 45 nm and cuboidal in shape. This is identified from the characterization studies that includes X-ray diffraction (XRD), UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Field emission scanning electron microscopy (FESEM), and Dynamic Light Scattering (DLS). Thus, the study has identified that the hydrothermal synthesis of nanomaterials is easy to synthesize, feasible and efficient. Some biological assays such as alpha-amylase and alpha-glucosidase inhibition for anti-diabetic activity, cytotoxicity assays for anticancer activities and various other biological assays were carried out for different purposes. All these assays have proved that the nanomaterial extracted from Crotalaria pallida leaf extract has applicability in various fields. Interestingly most of the assays provide increased activity in increased concentration of nanomaterial and proved their therapeutic effect on medicine.

Condensed tannins from Pinus radiata bark: Extraction and their nanoparticles preparation in water by green method

This work reports for the first time the production of condensed tannin nanoparticles stable in water via modification with glycine betaine. Pine bark, as a byproduct from the paper industry, was used as a source of condensed tannins of high molecular weight. Different glycine betaine concentrations were tested to produce condensed tannin nanoparticles, and the obtained nanoparticles were subjected to several characterization techniques (Dynamic Light Scattering, Field emission scanning electron microscopy, Zeta potential, Fourier transform infrared spectroscopy-Attenuated total reflectance, thermogravimetric analysis). The results showed that the highest stability possessed nanoparticles with 40 wt% glycine betaine. The average particle size distribution evaluated by scanning microscopy was 124 nm. Besides, the glycine betaine-modified condensed tannin nanoparticles demonstrated higher thermal stability with the starting degradation temperature at 238 °C. Finally, obtained nanoparticles showed an antioxidant capacity of 34,209 ± 2194 μmol ET/100 g and low cytotoxicity towards healthy human cells, representing the high potential to be used as a carrier of active compounds in agriculture, food, drug and medical sector.

CuO nanoparticles' effect on the photosynthetic performance in seed tissues of Inga laurina (Fabaceae).

Copper oxide nanoparticles (CuONPs) have been produced on a large scale because they can be applied across various fields, especially in nano-enabled healthcare and agricultural products. However, the increasing use of CuONPs leads to their release and accumulation into the environment. The CuONPs uptaken by seeds and their implications on germination behavior have been reported, but little is known or understood about their impact on photosynthesis in seed tissues. To fill knowledge gaps, this study evaluated the effects of CuONP concentrations (0-300mg L-1) on the photosynthetic activity of Inga laurina seeds. The microscopy data showed that CuONPs had an average size distribution of 57.5 ± 0.7nm. Copper ion release and production of reactive oxygen species (ROS) by CuONPs were also evaluated by dialysis and spectroscopy experiments, respectively. CuONPs were not able to intrinsically generate ROS and released a low content of Cu2⁺ ions (4.5%, w/w). Time evolution of chlorophyll fluorescence imaging and laser-induced fluorescence spectroscopy were used to monitor the seeds subjected to nanoparticles during 168h. The data demonstrate that CuONPs affected the steady-state maximum chlorophyll fluorescence ( ), the photochemical efficiency of photosystem II ( ), and non-photochemical quenching ( ) of Inga laurina seeds over time. Besides, the significantly increased at the seed development stage, near the root protrusion stage, probably due to energy dissipation at this germination step. Additionally, the results indicated that CuONPs can change the oscillatory rhythms of energy dissipation of the seeds, disturbing the circadian clock. In conclusion, the results indicate that CuONPs can affect the photosynthetic behavior of I. laurina seeds. These findings open opportunities for using chlorophyll fluorescence as a non-destructive tool to evaluate nanoparticle impact on photosynthetic activity in seed tissues.

Immunoinformatics design and synthesis of a multi-epitope vaccine against Helicobacter pylori based on lipid nanoparticles

Helicobacter pylori (H. pylori) is responsible for various chronic or acute diseases, such as stomach ulcers, dyspepsia, peptic ulcers, gastroesophageal reflux, gastritis, lymphoma, and stomach cancers. Although specific drugs are available to treat the bacterium's harmful effects, there is an urgent need to develop a preventive or therapeutic vaccine. Therefore, the current study aims to create a multi-epitope vaccine against H. pylori using lipid nanoparticles. Five epitopes from five target proteins of H. pylori, namely, Urease, CagA, HopE, SabA, and BabA, were used. Immunogenicity, MHC (Major Histocompatibility Complex) bonding, allergenicity, toxicity, physicochemical analysis, and global population coverage of the entire epitopes and final construct were carefully examined. The study involved using various bioinformatic web tools to accomplish the following tasks: modeling the three-dimensional structure of a set of epitopes and the final construct and docking them with Toll-Like Receptor 4 (TLR4). In the experimental phase, the final multi-epitope construct was synthesized using the solid phase method, and it was then enclosed in lipid nanoparticles. After synthesizing the construct, its loading, average size distribution, and nanoliposome shape were checked using Nanodrop at 280 nm, dynamic light scattering (DLS), and atomic force microscope (AFM). The designed vaccine has been confirmed to be non-toxic and anti-allergic. It can bind with different MHC alleles at a rate of 99.05%. The construct loading was determined to be about 91%, with an average size of 54 nm. Spherical shapes were also observed in the AFM images. Further laboratory tests are necessary to confirm the safety and immunogenicity of the multi-epitope vaccine.

Designing highly active hydrotalcite-derived NiAl catalysts for methane cracking to H2

Designing nickel-based methane cracking catalysts with excellent catalytic activity and surveying their transition during the catalytic process with varied reaction condition have been challenge. In this paper, NiAl catalysts were prepared by reduced hydrotalcite precursor for efficient catalytic methane cracking to produce hydrogen. The catalysts were characterized by XRD, N2 physisorption, XPS, SEM, TEM, Raman and TGA. The effects of preparation method, Ni/Al ratio and reaction temperature on methane cracking performance were revealed and the transformation for the Ni particles during the reaction process was analyzed. The results indicated that the catalyst performance of hydrotalcite-derived NiAl catalysts is superior to Ni/Al2O3 catalysts prepared by the conventional impregnation method, which maybe due to the better Ni dispersion and uniform average particle size distribution with around 12.7 nm compared with the agglomeration of the Ni/Al2O3 particles for up to 53.2 nm. The catalyst with a Ni/Al molar ratio of 3 exhibited the optimal catalytic activity with a stability for 75 min at nearly 90 % hydrogen yield at 700 °C. The reaction temperature also suggested a positive correlation between the hydrogen yield and the reaction temperature from 600 °C to 800 °C. Moreover, based on the investigation of the catalysts during the reaction transition state, Ni particles sintered rapidly from 10.2 nm to 31.2 nm at the beginning reaction time with the high hydrogen yield and then tended to be stable, which may be correlated well with the degree of graphitization of the deposited carbon. This paper provides a valuable design for efficient methane cracking catalysts.

Phytofabrication, characterization of silver nanoparticles using Hippophae rhamnoides berries extract and their biological activities.

Fabrication of plant-based metal nanoparticles has yielded promising results, establishing this approach as viable, sustainable, and non-toxic in the biomedical sector for targeted drug delivery, diagnostic imaging, biosensing, cancer therapy, and antimicrobial treatments. The present work demonstrates the suitability of Hippophae rhamnoides berries for the instant green synthesis of silver nanoparticles to check their antioxidant, lipid peroxidation, and antimicrobial potential. The preliminary characterization of Hippophae rhamnoides-mediated AgNPs was validated by monitoring the color shift in the solution from pale yellow to reddish brown, which was further confirmed by UV-vis spectroscopy and the plasmon peaks were observed at 450 nm. Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffraction (XRD) were used to evaluate the surface topography and structure of AgNPs. Herein, the antioxidant potential of synthesized AgNPs was investigated using DPPH free radical assay and the antimicrobial efficacy of similar was checked against E. coli and S. aureus by following MIC (minimum inhibitory concentration) and MBC (Minimum bactericidal concentration) assay. Along with the inhibitory percentage of lipid peroxidation was analysed by following TBARS (Thiobarbituric acid reactive species) assay. The results revealed that the AgNPs were spherical in shape with an average size distribution within the range of 23.5-28 nm and a crystalline structure. Negative zeta potential (-19.7 mV) revealed the physical stability of synthesized AgNPs as the repulsive force to prevent immediate aggregation. The bioactive functional moieties involved in reducing bulk AgNO3 into AgNPs were further validated by FTIR. TBARS was adapted to test lipid peroxidation, and Hippophae rhamnoides-mediated AgNPs showed a 79% inhibition in lipid peroxidation compared to Hippophae rhamnoides berries extract as 65%. Furthermore, the antibacterial tests showed 37 ± 0.01 mm and 35 ± 0.0132 mm, zones of inhibition against E. coli MTCC 1698 and S. aureus MTCC 3160 with MIC and MBC values of 1 mg/mL, respectively.

Evaluating the properties that affect the quality of the charcoal product, determining the limits of toxic emissions during combustion, and studying their impact on human health.

This research focuses on examining the potential impact of charcoal briquettes and lumps on human health due to the emissions they release, and verifying their quality standards. Quality assessment was conducted using a device capable of measuring toxic gases to identify contaminants from various sources such as biomass, synthetic resins, coal, metals, and mineral matter. Toxicity assessments were carried out on five types of briquettes and two varieties of lump charcoal. All charcoal samples were subjected to elemental analysis (SEM/EDAX), including the examination of Ca, Al, Cr, V, Cu, Fe, S, Sr, Si, Ba, Pb, P, Mn, Rb, K, Ti, and Zn. The results showed that burning lump charcoal had toxicity indexes ranging from 2.5 to 5, primarily due to NOx emissions. Briquettes, on the other hand, exhibited higher toxicity indices between 3.5 and 6.0, with CO2 being the main contributor to toxicity. The average 24-h CO content of all charcoal samples exceeded the World Health Organization's 24-h Air Quality Guideline of 6.34ppm, with a measurement of 37ppm. The data indicates that most of the products tested did not meet the prevailing quality standard (EN 1860-2:2005 (E) in Appliances, solid fuels and firelighters for barbecuing-Part 2: Barbecue charcoal and barbecue charcoal briquettes-Requirements and test method, 2005), which specifies a maximum of 1% contaminants, with some products containing as much as 21% impurities. The SEM analysis revealed irregularly shaped grains with an uneven distribution of particles, and the average particle size distribution is quite broad at 5μm. Malaysia Charcoal had the highest calorific value at 32.80MJ/Kg, with the value being influenced by the fixed carbon content-higher carbon content resulting in a higher calorific value.