X-ray Analysis Research Articles

Microbial mat textures from the Neoarchaean Donimalai Formation (Sandur Schist Belt) in the Dharwar Craton of India

Microbially induced sedimentary textures are reported from the Neoarchaean Donimalai Formation (Dharwar Supergroup) of the Sandur Schist Belt in India. These occur in chert bands interlayered with banded iron formations (BIFs). The textures appear as interspersed carbonaceous specks lining flat or wavy laminae that build into a strand-like carbonaceous meshwork. Raman spectroscopy indicates the presence of organic carbon. Elemental mapping using field emission scanning electron microscopy with energy-dispersive X-ray (FE-SEM-EDAX) analyses supports a biogenic origin. The presence of syngenetic microbial mat textures in the BIFs of the Donimalai Formation suggests microbially mediated oxidation and deposition of Fe in the predominantly anoxic Neoarchaean Ocean. Yogmaya Shukla* [yogmayashukla@bsip.res.in], Mukund Sharma [sharmamukund1@rediffmail.com], Arif H. Ansari [a.h.ansari@bsip.res.in], Veeru Kant Singh [veerukantsingh@bsip.res.in], Birbal Sahni Institute of Palaeosciences, 53 University Road, Lucknow 226 007, India; Nora Noffke [nnoffke@odu.edu], Old Dominion University, Oceanography & Physics Building, Norfolk, 23529, VA, USA.

Wear Behaviour of Friction Surfaced Al-Ni and Al-SiC Coatings over Mild Steel

Abstract The friction surfacing (FS) method offers solid-state deposition of both identical and distinct coatings while avoiding a number of the issues that encompass the traditional fusion coating process. This study investigates FS for depositing aluminium based metal matrix composites (MMCs) onto AISI1018 mild steel substrates. The Al-2Si-15SiC and Al7075-15Ni MMC consumables used for the FS process were fabricated via stir casting. The FS process, optimized at 1200 rpm for Al-SiC and 1500 rpm for Al-Ni, resulted in refined microstructures and enhanced properties. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) of the coating reveals surface with equiaxed and fine grains. The development of Al3Ni intermetallic compounds at the coating's interface strengthens the bond by allowing the substrate and coating material to diffuse into each other. An excellent bonding strength of 147 MPa and 142 MPa is observed for the Al7075-15Ni and Al-2Si-15SiC coating deposits, respectively. In comparison to MMC consumable rods, the FS composite coating delivers 80–85% reduction in grain size and enhances hardness. Vickers microhardness tests showed substantial hardness increases, with Al-Ni coatings reaching 183 HV. Wear tests indicated that Al-Ni coatings outperformed Al-SiC coatings and the steel substrate, exhibiting lower wear rates and friction coefficients. This research underscores FS's effectiveness in improving the properties of aluminium MMC coatings on mild steel, with Al-Ni coatings showing exceptional wear resistance and bond strength for industrial applications.

Mechanisms of air bubble rise in cement suspensions studied by X-ray analysis

The de-airing of fresh concrete is a crucial step in ensuring sustainable and durable concrete structures. Currently, proper de-airing is ensured by adjusting the fresh concrete consistency i.e. its rheological properties, without any knowledge whether this will actually guarantee sufficient de-airing. The exact relationship between the rheological properties and air bubble dynamics in concrete is not yet understood. In this paper, a detailed study was carried out in which air bubbles of different size and volume were injected in fresh cement suspensions with varying solid volume fractions (i.e. varying rheological behaviour). The air bubbles were visualised by means of X-ray radiography and the rise behaviour was evaluated with image based algorithms. It was found that in more viscous suspensions (i.e. higher particle contents) the bubble speed increases with decreasing suspension viscosity. For suspensions with higher flowability (i.e. less particle content), the inertial forces dominate the viscous forces, with the viscosity playing a subordinate role. The shear rate induced by an ascending air bubble is sufficient to locally reduce the dynamic viscosity of the suspension. In addition, it leads to shear-induced particle migration, with less concentrated regions in the ascending channel. Consequently, subsequent bubbles are influenced by changes of viscosity in this channel, rising faster and having different bubble shapes.

A simple and effective non-invasive method for the analysis of volatile organic compounds in exhaled air

Breath analysis is a cutting-edge technique that collects significant medical information by analyzing the substances found in exhaled breath. Fluctuations in the levels of chemicals such as acetone can serve as indicators of medical ailments or contact with hazardous substances such as occupational exposure. In order to detect acetone in exhaled air, techniques such as needle trap coupled with gas chromatography have been devised. This procedure involves the use of a nanocomposite called Mil101(Fe)@Fe3O4@SiO2.The nanocomposite is synthesized using a chemical hydrothermal method. In order to examine the properties of the Mil101(Fe)@Fe3O4@SiO2 nanocomposite, researchers utilized a range of analytical techniques including scanning electron microscopy (SEM), thermal analysis (TGA), x-ray analysis (EDX), Brunauer-Emmett-Teller (BET) method, and Fourier Transform Infrared Spectroscopy (FT-IR). The efficiency of the NTD-GC-FID method depends on several parameters, such as temperature, desorption time, fracture passage volume, sampling time, sample temperature, and sampling flow rate. These parameters have been studied using the simplex method to optimize the process. The optimal conditions yielded a limit of detection (LODs) of 0.4 µg/L and a limit of quantification (LOQs) of 1.1 µg/L. The calibration curve for the NTD-GC-FID method ranged from 0.011 to 10 mgl−1 with an acceptable error range. Moreover, the method demonstrated good repeatability and reproducibility, with calculated values of 3.9 and 4.6 %, respectively. The proposed method was successfully employed in this study to identify and measure acetone in the exhaled air of individuals with diabetes, yielding satisfactory results. The needle trap tool was used over 100 times without any decline in its efficiency for adsorbing acetone. In summary, this research presents a new analytical approach, namely the NTD-GC-FID method, to detect and measure acetone in exhaled air. Compared to the other methods for analyzing acetone, the application of Mil101(Fe)@Fe3O4@SiO2 nanocomposite demonstrated promising results in detection of diabetes.

Creep-fatigue interactive behavior and damage mechanism of TP321 stainless steel under hybrid-controlled conditions

In this study, Hybrid-controlled creep-fatigue (HCCF) tests were conducted on TP321 austenitic stainless steel under a variety of test conditions. The effects of strain amplitude, holding time, holding stress and temperature on the creep-fatigue behavior of TP321 austenitic stainless steel were not only analyzed in detail but also revealed the creep-fatigue damage interactive mechanism. The results demonstrated that a rise in test temperature and load holding time markedly induced creep deformation, resulting in a notable reduction in failure life. Additionally, an increase in test temperature led to the cessation of the cyclic hardening phenomenon. Secondly, the analysis of fracture morphology and X-ray computed tomography (X-CT) scanning results demonstrated that the transgranular cracks expanded inwards and connected with the intergranular voids under creep-fatigue interaction, forming a mixed intergranular and transcrystalline fracture mode. The presence of large creep cavities impeded the propagation of fatigue cracks when creep damage was the dominant phenomenon. Subsequently, the damage evolution mechanism was elucidated through microstructural analysis, which revealed that the impact of the slip bands on the triangular grain boundaries and the precipitation of carbides facilitated the nucleation of voids and the internal formation of intergranular microcracks, thereby causing creep-fatigue damage interaction. Finally, the TP321 austenitic stainless steel creep-fatigue damage interactive mechanism diagram was proposed in conjunction with the fracture morphological characteristics and microstructure.

A new indanone based dyes bearing dicyanomethylene and salicylidene moieties for selective detection cyanide anion and aromatic amines

Novel chemosensors that are indan-1-one dyes bearing salicylidene moiety were synthesized with good yields and characterized by FT-IR, 1H NMR, 13C NMR, and HRMS methods. Moreover, the molecular structure of 7 was characterization by X-ray and Environmental scanning electron microscopy (ESEM) analyses. The chemosensor potential of dyes were examined in a variety of basic conditions that include various anions, organic amines, and pH ranges by absorption and fluorescence spectra. The naked-eye detection of instant color changes was also observed. The deprotonation mechanism between dyes and anions was investigated by reversibility and 1H NMR studies. pKa values were determined in buffer solution with pH 6–11. Furthermore, organic amines were investigated and found they have two different interaction mechanism, deprotonation and addition. Density Functional Theory (DFT) were used for supporting the experimental results. In addition, the second-order nonlinear optical property of dyes were investigated and showed moderate μβ values.

Efficient electrochemical water oxidation catalyzed by a novel nickel complex: Critical effect of the flexibility of pyridine-amine based pentadentate ligand on catalytic property

Efficient electrochemical water oxidation can be realized by reasonable modulation of the ligand structure of metal complex-based molecular water oxidation catalysts (WOCs). Herein, the synthesis and prowess in electrocatalytic water oxidation of a mononuclear water-soluble nickel complex, [Ni(tmbptu)(OH2)](ClO4)2 (1, tmbptu = 2,6,10-trimethyl-1,11-bis(2-pyridyl)-2,6,10-triazaundecanone), is reported for the first time. Complex 1 is found to be an efficient homogeneous WOCs under near neutral condition with long-term catalytic stability by a series of characterizations, including dynamic light scattering (DLS) measurement, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray (EDX) analysis, chelation experiment, and Fe3+ test. Electrochemical tests reveal that water oxidation is accomplished via the generation of NiIV species generated by two successive e−/H+ proton coupled electron transfer (PCET) processes. Astonishingly, compared to the homologous complex [Ni(tmbptn)(OH2)](ClO4)2 (2, tmbptn = 2,5,8-trimethyl-1,9-bis(2-pyridyl)-2,5,8-triazanonane), which is a well-defined molecular WOC with high catalytic onset overpotential, 1 displays lower onset overpotential and much higher catalytic activity. This work suggesting that though the tertiary amine coordination environment have gain effect on the redox potential of metal center due to its poor sigma-donor effect, resulting in high onset overpotential of metal complex for water oxidation, this negative impact of the pyridine-amine ligand on the catalytic properties of complex can be weaken by adjusting the flexibility of backbone of those ligands.

Optimizing Electroconductive PPy-PCL Scaffolds forEnhanced Tissue Engineering Performance.

The integration of electrically conductive materials is a promising approach in tissue regeneration research. The study presented focuses on the creation of electroconductive scaffolds made from polypyrrole-polycaprolactone (PPy-PCL) using optimal processing parameters. Utilizing Box-Behnken response surface methodology for insitu chemical polymerization of PPy, the scaffolds exhibited a maximum conductivity of 2.542 mS/cm. Morphological examination via scanning electron microscopy (SEM) indicated uniform dispersion of PPy particles within PCL fibers. Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray (EDX) analysis validated the composition of the scaffolds, while mechanical testing revealed that the optimized scaffolds exhibit superior tensile strength and Young's modulus compared to scaffolds comprised only of PCL. The hydrophilicity of the scaffolds was improved considerably, transitioning from initially hydrophobic to fully hydrophilic for the optimum scaffold, making it suitable for tissue engineering applications. Cell viability assays, including MTT with L929 fibroblasts and Alamar Blue with bone marrow mesenchymal stem cells (bmMSCs), reflected no cytotoxicity. They showed an increase in metabolic activity, suggesting the capability of the scaffolds to support cellular functions. In conclusion, the insitu synthesis of PPy in the PCL matrix by optimizing the fabrication parameters resulted in conductive scaffolds with promising structural and functional properties for tissue engineering.

Finely controlled bioceramic granules and sonoporation for osteogenic bone defect repair and reconstruction

Osteoporotic fractures caused by imbalance in bone homeostasis like chemotherapy, loss of ovarian function，glucocorticoid use and aging require special surgical procedure to treat and restore anatomical function. However, due to escalating bone weakness and impairment, it remains a clinical challenge to treat these types of fracture defects through conventional means. Herein, we fabricated a novel calcium silicate‑strontium (CS-Sr35) bioceramic granules with high biological properties and combined it with ultrasound aided sonoporation (sono) in augmenting osteoporotic critical-sized bone defect. The use of sonoporation mediated by microbubble was to influence efficient response for tissue permeability and delivery of bioactive ions from the bioceramic scaffold. The graded robust granule with adjustable microstructure exhibited physiochemical and biointegration properties favorable for ion release in vitro and osteogenic related activities in vivo. Herein, we compared the treatment of bone defect repair using (i) no scaffold (ii) CS-Sr35 only and (iii) CS-Sr35 + sono. The gradual bone repair process was elucidated by X-ray, histology and micro-CT analyses. Overall, our results showed that the CS-Sr35 + sono exhibited a tailored biodissolution behavior with complete defect repair and reconstruction. Meanwhile, the group with only CS-Sr35 granules had less osteoblastic healing while the blank group showed inadequate critical-sized defect repair throughout the study. Our study suggests that, the synergistic technique of combining bioceramic granule with sonoporation significantly optimizes osteogenic activity and biomineralization ability of the bioceramic granule for new bone growth in osteoporotic pathology and also this tailored technique provides versatile approach for improving the biological effect for next generation reconstruction and repair of diseased bone defect.

The Feasibility of Using Lignin as Modifier for Asphalt Cement

Modifying asphalt cement is an effective approach to enhance the performance of asphalt concrete. This study evaluates the physical properties of lignin-modified asphalt (LMA) at various lignin percentages. The initial step involved extracting lignin from the pinus wood sawdust using the soda process. Subsequently, the extracted Soda Lignin Powder (SLP) was characterized through Fourier transformation infrared spectroscopy (FTIR), and Scanning Electron Microscopy-Energy Dispersive X-ray Analysis (SEM/EDX) to examine the changes in the chemical structure of lignin after extraction by soda process. Following this, three asphalt blends containing varying amounts of SLP (2%, 4%, 6%) by weight of asphalt cement were produced to assess physical properties such as penetration, softening point, ductility, and rotational viscosity test. The findings indicate that incorporating SLP into asphalt cement increases stiffness and viscosity compared to virgin asphalt cement, with increasing SLP content. These results suggest that lignin presents significant enhancement to the performance of asphalt cement under high service temperature conditions.

In vitro and in vivo studies of a decanuclear Ni(II) complex as a potential anti-breast cancer agent

A non-platinum-metal decanuclear complex [Ni10L4(CH3COO)8 (C2H5OH)8]·8(C2H5OH) (Ni10 complex) has been developed with a tri-dentate 2,3-dihydroxybenzaldehyde-2-aminophenol Schiff base ligand (H3L). Single crystal X-ray analysis reveals that the Ni10 complex displays a sandwich loaf-shaped decanuclear structure and its anticancer activity was evaluated. The cell cytotoxicity results indicating that the Ni10 complex is most effective to human breast cancer cells MDA-MB-231 and its mechanism were further investigated. Flow cytometry analysis showed that the Ni10 complex triggered cell cycle arrest and induced apoptosis of MDA-MB-231 cells. Western blot analysis of the changes of intracellular protein expression showed that Ni10 triggers MDA-MB-231 apoptosis through mitochondrial mediated apoptosis signaling pathways. In vivo experiments showed that the Ni10 complex significantly suppressed breast tumor growth with low toxicity against major organs in a nude mice model. The good treatment effect, low toxicity and pharmacological mechanisms of the decanuclear NiII complex may provide a clue for the research and development of non-platinum multinuclear based chemotherapeutic drugs.

HTXRD based lattice thermal expansion and specific heat capacity modelling of C15-Fe2Zr Laves phase

Crystallographic phase pure C15-Fe2Zr was obtained through arc melting technique. X-ray Diffraction (XRD), scanning electron microscope (FESEM) along with energy-dispersive X-ray analysis (EDS) and differential scanning calorimetry (DSC)were employed to study the single phase in Fe-33.3at.% Zr alloy. Rietveld refinement of the high-temperature XRD patterns (from 298K-873 K) revealed the average linear and volumetric coefficients of thermal expansion of the alloys as αai= 0.3643 × 10−5 K−1 and αVi = 1.0916 × 10−5 K−1, respectively. The experimental heat capacity and enthalpy increment of the C15-Fe2Zr phase from 310K to 890K was modelled employing Quasi-harmonic Debye Grüneisen theoretical modelling by identifying the vibrational, electronic, anharmonic and magnetic contributions. Curie temperature(~625K) was determined from the magnetic contribution of the heat capacity.

Sensitivity of Newly Prepared Nanomaterials to NO2 Gas and its Importance on Environmental and Industrial Safety

Polyaniline (PANI) and manganese dioxide (MnO2) doped with nickel oxide (NiO) nanocomposite have emerged as promising materials for gas sensing applications due to their high conductivity and surface area. This study improves the synthesized PANI/MnO2:NiO nanocomposites' sensitivity towards NO2 gas. Atomic force microscopy (AFM), Fourier transfer infrared (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), and X-ray diffraction (XRD) were used to analyze the produced nanocomposites. More precise methods were investigated to identify problems associated with oxidation, corrosion and sensor activity, such as increasing the amount of added nickel oxide, changing the structure of nanocomposites, and regulating the working temperature and humidity. Based on the results of this study, it is critical to comprehend how sensitive nanomaterials are to NO2 gas because exposure to this pollutant can negatively impact the environment and human health. Strategies to reduce its effects and improve industrial and environmental safety can be devised based on how nanomaterials react to nitrogen dioxide gas. We also examine antioxidants and PANI/MnO2:NiO nanocomposites for their anti-corrosion properties to guarantee long-term stability with the sensor's conductivity. Strong antioxidant and corrosion-resistant substances should be added to the sensor to extend its lifespan and maintain its performance under challenging operating conditions. Integrating these sensitive nanomaterials into gas-sensing devices can significantly improve environmental monitoring and industrial safety protocols, ultimately contributing to better air quality management and public health protection.

Influence of gaseous dielectrics on the wettability of Al-6061 alloy using dry μ-electrical discharge milling

Superhydrophobic surfaces are essential for applications such as self-cleaning and corrosion resistance. This study explores the fabrication of superhydrophobic surfaces on Al-6061 alloy using dry micro electrical discharge milling (μEDM milling) and investigates the effects of gaseous dielectrics on wettability under atmospheric conditions. Surfaces machined in an oxygen environment showed a surface area roughness (Sa) of 4.68 μm, 73.3 % higher than those machined in argon, attributed to enhanced metal oxide formation. Energy Dispersive X-ray Analysis (EDAX) indicated a significantly elevated O/Al atomic ratio of 0.80 for oxygen-machined samples, which was 73.9 % greater than argon-machined samples, suggesting the presence of hydrophilic compounds such as AlO(OH) and Al2O3. Additionally, X-ray Photoelectron Spectroscopy (XPS) revealed that Al2O3 peaks on oxygen-machined surfaces were broadened and shifted to higher binding energies, correlating with decreased contact angles and increased surface hydrophilicity. These results suggest that using oxygen as a dielectric in theelectrical discharge machining (EDM) process promotes oxide layer formation, resulting in hydrophilic characteristics, while machining in argon encourages organic adsorption and greater hydrophobicity. The findings of this research provide insights that can inform future efforts to tailor surface properties for advancements in aerospace, automotive, and biomedical engineering applications.

Green synthesis of silver nanoparticles from supercritical CO2 mediated Lagerstroemia speciosa extract: Characterization, antimicrobial and antibiofilm activity

In the current study, optimal supercritical fluid extract (SFE) of Lagerstroemia speciosa (LS) leaves at pressure 29.59 megapascal (MPa), temperature 89.50 ºC and extraction time 53.85 min. was used to extract phenolic compounds for the synthesis of silver nanoparticles (AgNPs). The synthesis was studied for 0-20 hrs. Initially the synthesis of nanoparticles (SFELS-AgNPs) was confirmed using UV -spectroscopy. It demonstrated a maximum surface plasmon resonance at 430 nm. The crystallite dimension of nanoparticles was determined using X-ray diffraction (XRD) (13.47 nm), Transmission electron microscopy (TEM), zeta potential analysis and energy-dispersive X-ray analysis (EDAX) were used to analyze the morphology, surface charge and presence of differential elements in SFELS-AgNPs respectively. Developed nanoparticles revealed antimicrobial activity against two gram-positive viz. Staphylococcus aureus and Bacillus cereus, and three gram-negative bacteria viz. Klebsiella pneumonia, Pseudomonas aeruginosa and Escherichia coli. The nanoparticle showed a minimum inhibitory concentration (MIC) of 64 μg/ml whereas the minimum bactericidal concentration (MBC) 128 μg/ml against K. pneumonia. They significantly inhibited K. pneumonia biofilm formation which was confirmed using scanning electron microscopy (SEM). The results were encouraging compared to the standards drug Chloramphenicol and other controls. The generated nanoparticles have highly effective antimicrobial properties against pathogenic bacteria.

Fabrication, characterisation, physicochemical and biological studies of gelatin/PVA/ silk fibre with manganese substituted hydroxyapatite scaffold for bone tissue engineering application

In recent years, researchers have been aiming for the development of multifunctional materials to repair bone tissue. The development of metal, ceramic, glass, and composite implants is the subject of interest in bone tissue engineering. Among these, HAP (ceramic) is either combined with other components, such as polymers or doped with ions to give improved properties or to add novel characteristics. The present study is focused on fabricating a novel scaffold with the required properties. Here gelatin/PVA/SF-Mn-HAP (MGPS) was fabricated by electrospinning to prepare a nano-level scaffold. The manganese-hydroxyapatite (Mn-HAP) was prepared by hydrothermal method. The nano scaffold was fabricated using various wt % (20, 40, 60) of Mn-HAP (Ca5-x Mnx (PO4)3 OH) (x = 0.1, 0.5) with gelatin/PVA/silk fibre. The fabricated nano scaffold phase formation was confirmed by X-ray diffraction (XRD), the functional group belonging to the nano scaffold was confirmed by Fourier transform infrared spectroscopy (FTIR), the topography of the nano scaffold was seen by scanning electron microscopy and the composition of elements was noted from energy dispersive X-ray analysis (EDAX). From the results, the fabricated scaffold MGPS 16 (60 wt% of Mn-HAP (x = 0.5 M) with gelatin-PVA-silk fibre) showed the highest tensile strength of 95.61 MPa. The antimicrobial activity of MGPS 16 showed the zone of inhibition against S. aureus – 62 ± 1.36 mm,E. coli – 71 ± 1.24 mm and C. albicans – 70 ± 1.22 mm. The hemolytic (%) of the MGPS 16 was 1.86 %. The SEM images of biomineralized samples showed the formation of apatite on the surface of the nano-composite.

Organogermanium(IV) complexes with O,N,O’-tridentate Schiff bases: synthesis, electrochemical transformations, photophysical properties, and anti/prooxidant activity

A series of novel diorganogermanium(IV) complexes of the type [R2Ge(Ln)] (where R is Et, Ph) with O,N,O’-tridentate redox-active Schiff bases has been synthesized. Compounds 1–7 were characterized by 1H, 13C{1H} NMR, IR spectroscopy, and elemental analysis. The molecular structures of complexes 1, 3, and 7 in crystal state have been established using single-crystal X-ray analysis. The complexes are pentacoordinate mononuclear compounds of germanium(IV). The bond lengths in tridentate ligands correspond to their diamagnetic dianionic forms. The electrochemical properties of complexes 1–7 were studied by cyclic voltammetry. A feature of the electrochemical behavior of target complexes is the ability to form relatively stable reduced/oxidized species as a result of the one-electron transfer. The stability of electrogenerated forms is influenced by both the organic groups at the germanium(IV) atom and the substituents in the Schiff bases. The energy gap (ΔEel) between the boundary redox orbitals obtained from electrochemical data for the complexes varies from 2.43 to 2.60 eV, while the optical ΔE was observed in the narrow range (2.46 – 2.50 eV). Luminescent activity was detected for some complexes in the solution. The maximal values ​​of the relative quantum yield were determined for complexes containing an electron-withdrawing nitro group in the redox-active ligand. In the reaction with ABTS radical cation, compound 1 only possessed the radical scavenging activity while the other compounds are characterized by weak neutralizing properties. The dual anti/prooxidant action was observed for compounds 1–7 in the process of rat liver (Wistar) homogenate lipid peroxidation.

Microplastics in Morocco's most consumed fisheries: Chemical characterization, ecological traits, and implications for human health

The pervasive presence of microplastics (MPs) in the environment is well established, yet many critical questions remain about their distribution and potential impacts on both ecological and human health. To assess the risks that MPs pose, especially through marine ecosystems and human consumption, monitoring their ingestion by fish in natural environments is essential. This study investigated the contamination of 12 fish species, the most commonly consumed in Morocco, collected from the Atlantic Ocean off the Moroccan coast. Analysis of 240 fish (20 individuals per species) revealed that 100 % of the samples contained microplastics. MPs were detected in the gills, gonads, and gastrointestinal tracts of all 12 species. The average abundance of microplastics per fish ranged from 20.6 to 133.2 MPs, with the forms identified as fragments (60 %), fibers (30 %), films (8 %), and pellets and foams (1 %). Additionally, omnivorous and demersal species presented the highest levels of MP contamination. Infrared spectroscopy (ATR-FTIR) analysis identified seven polymers, with high-density polyethylene (34 %), polyethylene terephthalate (30 %), and polypropylene (17.5 %) being the most prevalent. The microplastics were predominantly dark or light in color, with a notable presence of red and blue particles. Fish ingest various sizes of microplastics, primarily particles smaller than 1 mm. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX) revealed that most MPs exhibited visible signs of weathering and contained inorganic components on their surfaces. The potential risk of MPs to fish, as assessed by the polymer hazard index (PHI), was categorized as level V, indicating that MPs may pose significant risks to human health. The highest estimated daily intake (EDI) of microplastics was found in children (1620 MPs/year), whereas the lowest intake was estimated in women (350 MPs/year) and men (337 MPs/year). Given the widespread presence of microplastics in commonly consumed fish species in Morocco, there is an urgent need for regulatory measures to ensure the safety of fisheries, both for domestic consumption and export. Policymakers should consider the development of guidelines for acceptable levels of microplastic contamination in fish to safeguard public health.

Effects of exopolysaccharides from Rhizobium tropici on transformation and aggregate sizes of iron oxides

Iron oxide transformations in soil significantly impact nutrient availability and plant health. This study investigated the interaction between exopolysaccharides (EPS), produced by Rhizobium tropici, and iron oxide (Fe3O4), focusing on their impact on the transformation, particle size, and zeta potential of iron oxides. The characterization of the EPS-iron oxide composites was carried out using X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Analysis (EDX). The EPS adsorption kinetics revealed chemisorption and diffusion as controlling processes for EPS adsorption on Fe3O4, while isotherm data with releasing proton indicated possible ion exchange and heterogeneous layered adsorption. Desorption studies suggested the high stability of EPS-iron complexes. Notably, EPS significantly increased the aggregate size of EPS-iron complexes at low EPS/iron oxide molar ratios but shrank the aggregate size at higher ratios (> EPS/iron oxide 2 × 10−4). Additionally, EPS complexation resulted in a shift in the zeta potential towards more negative surface functionality. Functional groups within EPS, specifically –COOH, –OH and –NH played a crucial role in the interaction of EPS with iron oxides. The study concluded that EPS coating prevented the transformation of Fe3O4 into other iron oxide forms like β-FeOOH, α-Fe2O3, and γ-Fe2O3, elucidating the significant role of EPS in soil mineral processes.

Experimental studies on dilution, microstructural, mechanical and wear characteristics of Inconel 718 deposited over stainless steel 304 employing cold metal transfer process

In this research, the sinewave weaving technique is used by the Cold Metal Transfer process for hard-facing the Inconel 718 over the Stainless Steel 304. A microstructural study exhibited columnar grains that were transformed into equiaxed grains. Scanning Electron Microscopy (SEM) – Energy Dispersive X-ray analysis (EDX) results confirm the element’s segregation and secondary phase’s formation. Outcomes of hardness, tensile, impact measurements, and wear analysis show that a hard-faced layer offers better hardness and wear resistance.