Dispersive X-ray Analysis Electron Research Articles

Ocean acidification will not affect the shell strength of juveniles of the commercial clam species Chamelea gallina: Implications of the local alkalinization of seawater

Ocean acidification (OA) is expected to decrease the strength of bivalves’ shells, especially during the early stages of development, with negative consequences to the resilience of natural populations and the economy. The objectives of the present study were to assess the long-term effect of increasing pCO2 after 217 days of exposure under controlled conditions of pH of ∼8.2, 8.0, and 7.7 on the strength and integrity of shells of juveniles of the commercial striped venus clam Chamelea gallina. Shell strength was estimated through compression tests and integrity through scanning electron microscopy (SEM) and dispersive X-ray analyses (EDX). The results showed that under increasing pCO2 the shell strength of juveniles is unaffected, which could be related to the locally elevated total alkalinity of seawater with respect to other parts of the coastal lagoon. However, despite this, it was also observed that the juvenile clams exposed to elevated pCO2 decreased their shell thickness and increased the porosity of their prismatic layer. Under future OA conditions, these changes could eventually compromise the integrity of the shells, becoming more vulnerable to the attack of predators and breakable during fishing operations. Future studies should address the plasticity of the organisms and the effect of the alkalinization of seawater on the resilience of shellfish juveniles under global change conditions.

Synthesis of eco-friendly bio-based coconut shell magnetic biochar for efficient bisphenol S sequestration in aqueous environment: green technology breakthrough

Water pollution has emerged as a critical global challenge, particularly the contamination of water bodies with persistent organic pollutants such as Bisphenol S (BPS), a known endocrine disruptor. This study presents the synthesis and application of eco-friendly bio-based coconut shell magnetic biochar (CSMB) for efficient sequestration of BPS from aqueous environments. Utilizing pyrolysis and co-precipitation techniques, the magnetic biochar was characterized through various methods including surface chemistry (pHpzc), electron dispersive X-ray analysis (EDX), Brunauer-Emmett-Teller (BET) N2 adsorption-desorption, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). SEM revealed a porous structure with a high surface area, while FTIR confirmed the presence of functional groups essential for adsorption. X-ray diffraction (XRD) and VSM successfully incorporated magnetic nanoparticles, enhancing the separation process post-adsorption. The CSMB demonstrated a significant surface area of 373 m2 g−1, outperforming regular coconut shell biochar (CSB), with a BPS adsorption capacity of 43.5 mg/g compared to 26.7 mg/g for CSB. Batch adsorption tests assessed the impact of operational factors such as initial BPS concentration (8–150 ppm), contact time (30–150 min), temperature (298.15, 318.15, and 338.15 K), pH (3–11), and CSMB dosage (0.1–0.9 g). The results indicated optimal adsorption at pH 6 with a maximum capacity of 52.3 mg/g. Kinetic studies revealed that the pseudo-second-order model best described the adsorption process, while the Langmuir isotherm model provided an excellent fit for the adsorption data. The reusability of CSMB was validated over five cycles, with adsorption capacity decreasing slightly from 43.5 mg/g to approximately 41 mg/g, making it a sustainable and effective adsorbent for water treatment.

Evaluating physiochemical characteristics of tragacanth gum-gelatin network hydrogels designed through graft copolymerization technique

The present work deals with the evaluation of the physiochemical and biomedical properties of hydrogels derived from copolymerization of tragacanth gum (TG) and gelatin for use in drug delivery (DD) applications. Copolymers were characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. FE-SEM revealed heterogeneous morphology and XRD analysis demonstrated an amorphous nature with short range pattern of polymer chains within the copolymers. The release of the drug ofloxacin occurred through a non-Fickian diffusion mechanism and the release profile was best described by the Korsmeyer-Peppas kinetic model. The hydrogels exhibited blood compatibility and demonstrated a thrombogenicity value of 75.63 ± 1.98 % during polymer-blood interactions. Polymers revealed mucoadhesive character during polymer-mucous membrane interactions and required 119 ± 8.54 mN detachment forces to detach from the biological membrane. The copolymers illustrated the antioxidant properties as evidenced by 2, 2′-diphenylpicrylhydrazyl (DPPH) assay which demonstrated a 65.71 ± 3.68 % free radical inhibition. Swelling properties analysis demonstrated that by change in monomer and cross linker content during the reaction increased the crosslinking of the network. These results suggest that the pore size of network hydrogels could be controlled as per the requirement of DD systems. The copolymers were prepared at optimized reaction conditions using 14.54 × 10−1 molL−1 of acrylic acid monomer and 25.0 × 10−3 molL−1 of crosslinker NNMBA. The optimized hydrogels exhibited a crosslink density of 2.227 × 10−4 molcm−3 and a mesh size of 7.966 nm. Additionally, the molecular weight between two neighboring crosslinks in the hydrogels was determined to be 5332.209 gmol−1.The results indicated that the combination of protein-polysaccharide has led to the development of hydrogels suitable for potential applications in sustained drug delivery.

Evaluation of physiochemical and biomedical properties of psyllium-poly(vinyl phosphonic acid–co-acrylamide)-cl-N,N-methylene bis acrylamide based hydrogels

Present investigation deals with the synthesis of psyllium based copolymeric hydrogels and evaluation of their physiochemical and biomedical properties. These copolymers have been prepared by grafting of poly(vinyl phosphonic acid) (poly (VPA)) and poly(acrylamide) (poly(AAm)) onto psyllium in the presence of crosslinker N,N-methylene bis acrylamide (NNMBA). These copolymers [psyllium-poly(VPA-co-AAm)-cl-NNMBA] were characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA)- differential thermal analysis (DTG). FESEM, AFM and XRD demonstrated heterogeneous morphology with a rough surface and an amorphous nature. Diffusion of ornidazole occurred with a non-Fickian diffusion mechanism, and the release profile data was fitted in the Korsemeyer-Peppas kinetic model. Biochemical analysis of hydrogel properties confirmed the blood-compatible nature during blood-polymer interactions and revealed haemolysis value 3.95 ± 0.05 %. The hydrogels exhibited mucoadhesive character during biomembrane-polymer interactions and demonstrated detachment force = 99.0 ± 0.016 mN. During 2,2-diphenyl-1-picrylhydrazyl reagent (DPPH) assay, free radical scavenging was observed 37.83 ± 3.64 % which illustrated antioxidant properties of hydrogels. Physiological and biomedical properties revealed that these hydrogels could be explored for drug delivery uses.

An investigation on the performance of vehicle brake pads developed from Cortaderia selloana based biomass

AbstractNowadays, researchers are making intense efforts to develop biomass-based industrial products. This study developed low-metallic and asbestos-free samples based on Cortaderia selloana (12–15% and 18% ratios), a natural species, to contribute to the brake pad field. The developed samples’ friction coefficient and wear rate experiments were carried out on a brake pad test device with a load of 1 MPa and a disk rotation speed of 6 m/s, according to the TS555 standard. Scanning electron microscopy and electron-dispersive x-ray analysis were performed on the worn surfaces of the samples. According to the results obtained, the wear rate increased while the average friction coefficient decreased in the brake pad samples using 18% Cortaderia selloana content in the sample content. In scanning electron microscopy analysis, primary and secondary plateau formations were observed on the worn surfaces of all samples. At the same time, samples containing 15% and 18% Cortaderia selloana also showed signs of abrasive wear. High friction coefficient and low wear rate are expected for brake pads to be used in automobiles. In general, the friction of brake pads must be within the range, and it is always necessary to balance the friction to avoid driver discomfort. However, except for some racing applications, a high coefficient of friction is only sometimes desirable, which can cause rotor wear problems. As a result of this research, a consistent friction coefficient and low wear rate for the brake pads with the brake pad sample containing 12% Cortaderia selloana.

Tailoring activity on effect of loadings over praseodymium oxide catalyst in methanation

Most methanation reactions used basic catalysts to achieve high CO2 conversions. Therefore, in this study, praseodymium oxide was selected and synthesized using ratio Ru/Mn/Pr (5:30:65) and Al2O3 as support. From the result, it successfully converted 96 % of CO2 gas at calcination temperature of 800 °C using one series reactor. When the praseodymium-based loading is varied, the trend CO2 conversion is higher at 65 %wt and slightly decreased when increased to 85 wt%. Then, two series furnace reactors were applied and the Ru/Mn/Pr (5:30:65)/Al2O3 catalyst exhibited a slightly increased CO2 conversion with 98 %. According to X-ray diffraction analysis, the catalyst is amorphous with the presence of active species MnO2 and Pr2O3. In contrast, FESEM analysis showed that the catalyst surface was covered with large crystalline solids of irregular size which align with amorphous structure. Electron dispersive X-ray analysis shows the presence of all active element. Meanwhile, surface area of catalyst is ​​59.22 m2/g from Nitrogen analysis.

Designing protein-polysaccharides based bioactive copolymeric network by supra-molecular interactions for sustained drug delivery

Keeping in view recent advancements in designing biomaterials from bioactive polysaccharides, the present work deals with the design of protein (gelatin)-polysaccharide (tragacanth gum) based bioactive copolymeric network by supramolecular interactions and covalent linkage for sustained drug delivery (DD) applications. The network copolymeric structure was characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). FESEM and XRD analyses revealed the heterogeneous morphology of copolymers with an amorphous nature. 13C NMR and FTIR spectra demonstrated the incorporation of poly(acrylamide) (AAm) into network structure by copolymerization reaction. Diffusion of anticancer drug 5-flurouracil (5-FU) occurred in a sustained manner with the Fickian mechanism and was best fitted in first order kinetic model. Polymer-blood interactions revealed the non-hemolytic character of hydrogels. An antioxidant assay evaluated their antioxidant property (26.61 ± 0.85 % of free radical scavenging). Copolymers exhibited mucoadhesiveness during polymer-mucous membrane interactions and required 113.33 ± 5.68 mN detachment forces. Furthermore, the combination of polysaccharide-gelatin has enhanced supramolecular interactions and improved physiological and biomedical properties of network hydrogels. Overall, these properties revealed the suitability of copolymeric hydrogels for drug delivery applications.

In-situ HYDROTHERMAL METHOD FOR GRAPHENE OXIDE/HYDROXYAPATITE SYNTHESIS FROM SCALLOP SHELLS

The graphene oxide/hydroxyapatite composite was synthesized using an in situ hydrothermal method. In this process, scallop shells (Amusium pleuronectes) were used as a source of calcium ions in fabricating the composite. Meanwhile, graphene oxide was exfoliated and oxidized from graphite powder. X-ray diffraction confirms that hydroxyapatite in the composite has a hexagonal structure. Also, the inclusion of graphene into the system did not alter the crystal structure. However, it affected the size of the apatite crystal deposited in the graphene surfaces layer, which was revealed by scanning electron microscopy analysis. The infrared spectra confirm some shiftings of the phosphate bands absorption, indicating electronic interaction between graphene and apatite matrix. Furthermore, from the Electron dispersive X-ray analysis obtained ratio of calcium/phosphate was found to be 1.84.

Polysaccharide gum based network hydrogels for controlled drug delivery of ceftriaxone: Synthesis, characterization and biomedical evaluations

In the present work dietary fibers gum acacia (GA) and tragacanth gum (TG) were applied in designing drug delivery (DD) carrier due to their therapeutic role and colon degradation. The grafted product was formed in the form of network hydrogels with polyacrylamide [poly(AAm)]. The polymer samples were characterized by Scanning electron micrograph (SEM), Electron dispersion X-ray analysis (EDAX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Thermo-gravimetric analysis (TGA). The formation of the grafted product and its heterogenous and amorphous nature was confirmed from FTIR, SEM and XRD. The mesh size of the network hydrogels was about 32.51 nm. The antibiotic drug ceftriaxone diffusion was non-Fickian from drug encapsulated GA-TG-cl-poly(AAm) network and release was fitted in first order kinetic model. The release of drug from network was slow and controlled manner due to drug-polymer interactions porous nature of the hydrogels. The polymer-blood interaction showed haemolysis values less than five percent which inferred biocompatible nature and polymer-biomembrane interactions indicated the muco-adhesiveness of the DD system. These properties reflected the suitability of the network hydrogel for site specific drug delivery.

Dairy manure pellets and palm oil mill effluent as alternative nutrient sources in cultivating Sporosarcina pasteurii for calcium carbonate bioprecipitation.

Microbially induced carbonate precipitation (MICP) is a process that hydrolysis urea by microbial urease to fill the pore spaces of soil with induced calcium carbonate (CaCO3 ) precipitates, which eventually results in improved or solidified soil. This research explored the possibility of using dairy manure pellets (DMP) and palm oil mill effluent (POME) as alternative nutrient sources for Sporosarcina pasteurii cultivation and CaCO3 bioprecipitation. Different concentrations (20-80 g l-1 ) of DMP and POME were used to propagate the cells of S. pasteurii under laboratory conditions. The measured CaCO3 contents for MICP soil specimens that were treated with bacterial cultures grown in DMP medium (60%, w/v) was 15·30 ± 0·04 g ml-1 and POME medium (40%, v/v) was 15·49 ± 0·05 g ml-1 after 21 days curing. The scanning electron microscopy showed that soil treated with DMP had rhombohedral structure-like crystals with smooth surfaces, whilst that of POME entailed ring-like cubical formation with rough surfaces Electron dispersive X-ray analysis was able to identify a high mass percentage of chemical element compositions (Ca, C and O), whilst spectrum from Fourier-transform infrared spectroscopy confirmed the vibration peak intensities for CaCO3 . Atomic force microscopy further showed clear topographical differences on the crystal surface structures that were formed around the MICP treated soil samples. These nutrient sources (DMP and POME) showed encouraging potential cultivation mediums to address high costs related to bacterial cultivation and biocementation treatment.

Elemental composition of Dust Particles and Influence of Dust Addition on Photovoltaic Module Performance

There is an excellence prospective for solar power practice in Nigeria by engaging solar photovoltaic (PV) units. Addition of dust on solar antennae and PV elements is a pronounced worry owing to different dust particles fouling on the module. The recitals of such devices are considerably suffering from dust addition. Dust samples involved during this study came from ash, cement, rice husk, brick dust, and sand. This paper therefore, reports the outcome of a research work on the elemental composition of dust particles and influence of dust addition on the maximum power, efficiency and performance ratio of a 3 W polycrystalline solar PV module. The electron dispersive x-ray analysis of the collected dust samples revealed silicon having the highest percentage weight composition while sulfur and nitrogen records 0 % in most of the sample apart from rice husk. The experimental measurements were conducted outdoor under 470, 715 and 756 W/m2 solar irradiation levels. Results indicated that dust addition on the solar PV module negatively affects the output power with cement dust proffering highest effect due to high percentage weight of carbon present in it. The research work revealed that solar PV modules polluted by dust particles for a period of time experienced a significant decrease in their efficiency and performance during operation. Accordingly, it is recommended that installed PV modules be cleaned routinely as dust particles hid on the solar panel naturally. Many areas have to be covered in future like construction sites, agricultural land and many more as solar power is growing exponentially in Nigeria.

Surface morphology properties of biochar feedstock for soil amendment

A soil amendment is any material added to a soil to improve soil physical properties, support plant growth, improve soil fertility, organic matter, and water holding capacity, improve soil chemical and biological properties. Biochar is an organic amendment that improve soil fertility, mitigates climate change, and effectively keeps nutrients and available to plants. The chemical and physical properties of the biochar are important to know the suitable applications of biochar. The chemical and physical properties of the biochar are depending on the process and biomass feedstock. The research aimed to find out the kind of biomass feedstock for biochar as a soil amendment. The biochar feedstock was evaluated using scanning electron microscopy (SEM) and electron dispersive X-ray (EDX) analysis and can predicting possible uses for the biochars. The result showed that the biochar surface morphology properties were influenced by the feedstock types and pyrolysis temperature. The pores development and mineral contents in coconut shell biochar are the most suitable for soil amendment.

In vitro antifungal studies of Ruthenium (III) complex derived from chitosan Schiff bases

The complex formation property is one of the versatile natures of chitosan Schiff base; this has been achieved by chemical modification of chitosan with various aldehydes. The vanillin, salicylaldehyde and ortho vanillin were used for chemical modification through a condensation reaction with chitosan. The primary amino group (–NH2) in chitosan biopolymer molecule readily react with an aldehyde (–CHO) to form Schiff base (imine). The chitosan Schiff base becomes a complexing agent or ligand containing azomethine group which is the yardstick for complex formation with metal ions. The Ruthenium (III) complexes were obtained by complexation of Ruthenium metal ion with Schiff base ligands. Ruthenium (III) complexes were screened by Scanning Electron Microscope with Electron Dispersive X-ray (SEM-EDAX) analysis. The newly synthesized chitosan Schiff base Ruthenium (III) complexes were administered for antifungal study by disc diffusion method. The antifungal results showed that the synthesized metal complexes having significant antifungal activities against fungal pathogens.

Chemical vapor deposition of germanium-rich CrGe x nanowires.

Chemical vapor deposition was applied to synthetize nanostructured deposits containing several sorts of nanoobjects (i.e., nanoballs, irregular particles, and nanowires). Analytical techniques, that is, high-resolution transmission electron microscopy, scanning electron microscopy, electron dispersive X-ray analysis, selected area electron diffraction, and X-ray photoelectron spectroscopy, showed that unlike nanoballs and particles composed of crystalline germanium, the layer was made of chromium germanide CrGex. The nanowires possessed a complex structure, namely a thin crystalline germanium core and amorphous CrGex coating. The composition of the nanowire coating was [Cr]/[Ge] = 1:(6–7). The resistance of the nanowire–deposit system was estimated to be 2.7 kΩ·cm using an unique vacuum contacting system.

Chemical, morphological characterizations of Ririwai biotite and determination of yield point of its weighting agent application in drilling mud


 
 
 Chemical, morphological characterizations and drilling mud yield point impact of Ririwai biotite have been investigated and reported in this work. Local Ririwai biotite mined in Doguwa Local Government Area of Kano State was used as a weighting agent in drilling mud formulation. Scanning Electron Microscopy (SEM) characterization, X-ray Diffraction (XRD) and Electron Dispersion X-ray (EDX) analysis of the Ririwai biotite were carried out. Water-based drilling mud was prepared using commercial bentonite according to the API 13A Standard. Effect of gradual addition of Ririwai weighting agent; 0 – 100 wt%, on the yield point of the formulated drilling mud was studied. XRD analysis showed that the dominant mineral phase in the material was biotite. Morphological analysis carried out showed that the Ririwai biotite had a sheet-like morphology while the commercial bentonite had clumpy morphology. The estimated average particle sizes were 60 and 25 μm for the Ririwai biotite and commercial bentonite, respectively. EDX analysis showed that silica-alumina ratio of the Ririwai biotite was 9.3 while that of the commercial bentonite was 1.58. The optimum yield point of the formulated drilling mud was 2.0 lb/100 ft2 corresponding to formulation having 0 – 30 wt% weighting agent composition. The specific gravity of Ririwai biotite was determined as 2.4.
 
 

The effect of PVP: BaTiO3 interlayer on the conduction mechanism and electrical properties at MPS structures

In this paper, the influence of doping barium titanate in the polyvinyl pyrrolidine polymer sandwiched between the metal-semiconductor on the conduction mechanism and the electrical properties of the formed diode has been examined. The barium titanate nanostructure is prepared by microwave assisted method. The TGD/DTA, x-ray diffraction pattern (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Electron Dispersive x-ray (EDX) and UV-Vis spectroscopy analyses are performed in order to determine the calcination temperature, average crystalline size, surface morphology, purity specification, and optical properties of the prepared barium titanate nanostructure, respectively. The main electrical parameters such as the ideality factor (n), barrier height (BH), leakage current (I0), shunt (Rsh) and series (Rs) resistances of the Al/PVP: BaTiO3/p-Si (MPS) and Al/p-Si (MS) structures are calculated by Thermionic Emission (TE), Norde, and Cheung methods by measuring the I–V characteristics of the both diodes at ±6 V and compared with each other. Moreover, the surface states density (Nss) as a function of energy at forward bias and the current conduction mechanisms at forward and revers bias are investigated. The rectifying ratio of MPS diode is enhanced by reducing the n, Rs, Nss, I0 and by increasing shunt resistance (Rsh), BH due to presence of interfacial layer. Therefore, PVP: BaTiO3 interlayer can be a suitable alternative replacement of intrinsic interlayer for utilization in the nanoscale electronic and optoelectronic devices and circuits.

New Ulva lactuca Algae Based Chitosan Bio-composites for Bioremediation of Cd(II) Ions

The current article covers the production of chitosan (CS) from shells of shrimp waste and its utilization in the preparation of eco-friendly imprinting and non-imprinting composites with Ulva lactuca algae (Alg). These bio-composites namely (Imp-Alg-25wt% CS) and (NImp-Alg-25wt% CS) were used for removal of Cd(II) ions. Fourier transform infrared (FT-IR) spectra, scanning electron microscope (SEM) equipped with electron dispersive X-ray (EDX), X-ray diffraction (XRD), and elemental analysis measurements were performed to characterize these bio-composites sorbents. The highest adsorption of these sorbents towards Cd(II) ions was determined as a function of solutions pH, contact time, Cd(II) ion concentration, beads dose, and temperature. The equilibrium experimental data were treated using various mathematical isotherm and kinetic models to approve the maximum bio-sorption capacities of NImp-Alg-25wt% CS and Imp-Alg-25wt% CS (in mg/g). The results exhibited that Imp-Alg-25wt% CS gave higher removal capacity than NImp-Alg-25wt% CS at the same optimum parameters. Pseudo-2nd order dynamic and Langmuir isotherm models were well described in these biosorption processes. Thermodynamically, the removal behavior of Cd(II) using both bio-composites was spontaneous at room temperature. The reusability of the sorbents, NImp-Alg-25wt% CS and Imp-Alg-25wt% CS, showed three cycles. In addition, comparative study was also conducted for Cd(II) removal onto some reported sorbents.

Amine-rich quartz nanoparticles for Cu(II) chelation and their application as an efficient catalyst for oxidative degradation of Rhodamine B dye.

The study describes the loading of the quartz SiO2 nanoparticles (NPs) with (3-aminopropyl)triethoxysilane (APTES) linker with simultaneous lengthening of the linker through the terminal amine group by glutaraldehyde (GA). The reactive polyethylenimine (PEI) was introduced to the surface to increase the ability to capture Cu(II) ions. The composite got the abbreviation SiO2/PEI-Cu(II). The Cu(II) ions were the active center with a peroxo-complex activation state. The composite characterization included scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) surface analyzer. The kinetics of the oxidative degradation of Rhodamine B (RhB) dye obeyed the pseudo-first order under flooding conditions. The reaction parameters including the catalyst dose, solution pH, initial concentration of reactants, and temperature got some attention. The obtained results showed that more than 91.7 ± 1% of RhB dye was degraded to CO2, NH4+, NO3-, H2O, and some inorganic acids after 30 min as confirmed by gas chromatography mass spectrometry and total organic carbon (TOC) measurements. Also, GC-MS spectra for water samples drawn from the reaction in successive periods had suggested a conceivable degradation pathway for RhB by hydroxyl radicals. Degradation starts with de-alkylation then carboxyphenyl removal followed by two successive ring-opening stages. Both the effects of the catalyst recycling and treated water reusability on the reaction rate were studied. The catalyst provided noticeable stability over three consecutive cycles.

In VitroEvaluation of Antifungal Activities by Permeation of Ru(III) Complexes Derived from Chitosan-Schiff Base Ligand

Background:The transition metal complexes are derived from a natural biopolymer which is a very potent material in various research areas of study.Objective:This study aims to show the preparation of ruthenium(III) complexes from chitosan Schiff base ligand for effective application in antifungal studies.Methods:Chemical modification was carried out through a condensation reaction of chitosan with some aromatic aldehydes, which resulted in the formation of a bidentate Schiff base ligand. The Ru(III) complexes were prepared by complexation of ruthenium metal ion with bidentate ligands. The series of Ru(III) complexes were characterized by Scanning Electron Microscope with Electron dispersive X-ray (SEM-EDX) analysis, Powder XRD. The biopolymer-based transition metal complexes have potential uses for their biological activities. The synthesized metal complexes were directed for antifungal study by the disc diffusion method.Results:The antifungal study results showed that the transition metal complexes have significant antifungal activities against some vital fungal pathogens such as Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Penicillim chryogenum and Trigoderma veride.Conclusion:A chitosan biopolymer offers some peculiar features such as biodegradability, biocompatibility etc., which are favorable for green synthesis of transition metal complexes through complexation with bidentate ligands. These metal complexes possess good antifungal property due to their chelation effect on micro-organisms.

Nanofluid from Palm Kernel Oil for High Voltage Insulation

A clean alternative insulating oil has been the quest of researches over the years due to non-degradability of mineral oil and safety issues. With the application of nanoscience and nanotechnology, the potential of transformer oil-based nanofluids has been thoroughly investigated with signs of significant improvement. Attention was placed on natural ester as a green alternative and it was realized that it has the potential to become a replacement for mineral oil. However, for natural ester-based nanofluids, the performance analysis is not well explored and there is still room for more investigations. This paper focused on the improvement of the physicochemical properties, dielectric loss and breakdown voltage of palm kernel oil ester using Al2O3 and TiO2 nanoparticles. The nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) equipped with electron dispersive X-ray analysis (EDX). The physicochemical properties, relative permittivity, dielectric loss, and high voltage DC conductivity of the nanofluid samples were studied with varying weight percentages of Al2O3 and TiO2 nanoparticles ranging from 0.2 wt% to 1 wt% in a step of two to understand the behaviour of the materials. The adequacy of the fluid samples as an electrical insulating fluid in oil-filled high voltage (HV) electric equipment was explored and compared. For both types of nanoparticles, the dielectric loss was observed to decrease at 1 wt% but with a more noticeable decrease when considering Al2O3 nanoparticle. Measurement of DC electrical breakdown voltage of the ester-based nanofluids revealed that the dispersion of nanoparticles in the fluid result in an increase in the breakdown voltage of the base fluid with the optimum value obtained at 0.6 wt%. The study indicated a decrease in the dielectric loss of the nanofluid sample and exhibited improved breakdown voltage when compared with the base alkyl ester.