Search

The co-doping of vanadium pentoxide (V2O5) with rare-earth (RE) elements, namely 1.5 % holmium (Ho) and 1.5 % ytterbium (Yb) has been conducted using an eco-friendly, straightforward hydrothermal approach to assess the combined effects on structural, optical, and photocatalytic properties. The application of the density functional theory (DFT) approach effectively examined the impact of RE ions on the photocatalytic efficiency of co-doped V2O5. The stable orthorhombic crystal structure of co-doped V2O5 has been confirmed using DFT and X-ray diffraction without a secondary phase. It appears that homogeneous nucleation occurs while heterogeneous nucleation slows down in co-doped samples, as evidenced by the larger crystallite sizes in co-doped samples compared to doped ones. It means a result, the co-doped samples exhibit photodegrades more quickly and have a higher rate constant than the doped samples. This is because they have less dislocation density (4.26 × 10−3 nm−2) and internal micro-strain (4.93 × 10−3). The bandgap and degradation efficiency are determined by the UV–vis spectroscopy and found to be 2.33 eV and 95 %, respectively, at the optimal pH of 7 in the visible range. The co-doped sample has a rate constant of 24 × 10−3 min−1, which is the highest in the RE-doped V2O5 system. This is a good reason to think of co-doped V2O5 as a possible catalyst.

Entrepreneurial knowledge and intention focus on understanding an individual’s interest in and abilities towards entrepreneurial activities. Another issue is the impact of cultural differences on entrepreneurial intention. The purpose of the study is to reveal the impact of entrepreneurship knowledge on entrepreneurial intention of international students receiving higher education in Turkey. We also examine whether there are differences in entrepreneurial knowledge and entrepreneurial intention according to gender, department, having an entrepreneurial business idea, receiving entrepreneurship education or not and monthly expenditure amount. The methodological basis of the study resides in the concept of entrepreneurial knowledge and planned behaviour theory. Among the research methods are frequency and regression analyses, parametric tests, convenience sampling method. A total of 380 students enrolled in 20 public and 5 private universities in Turkey in the 2021–2022 academic year participated in the survey and completed the questionnaire. Participants were reached through electronic and social media environments or face-to-face communication. The research results reveal that there are statistically significant differences between entrepreneurial knowledge and intention with educational status, entrepreneurial idea, department of study and the amount of monthly expenses. Furthermore, regression analysis showed that entrepreneurial knowledge and entrepreneurship education have a significant positive effect on students’ entrepreneurial intentions. The findings of this study provide valuable guidance for policymakers and curriculum preparers to understand international students’ entrepreneurial intentions and promote entrepreneurial intentions in universities.

Here we report the structural, elastic, bonding, thermo-mechanical, optoelectronic and superconducting state properties of recently discovered XIr3 (X = La, Th) superconductors utilizing the density functional theory (DFT) using two different exchange-correlations functionals. The elastic, bonding, thermal and optical properties of these compounds are investigated for the first time. The calculated lattice and superconducting state parameters are in reasonable agreement to those found in the literature. In the ground state, both the compounds are mechanically stable and possess highly ductile character, high machinability, low Debye temperature, low bond hardness and significantly high melting point. The thermal conductivities of the compounds are found to be very low which suggests that they can be used for thermal insulation purpose. The population analysis and charge density distribution map confirm the presence of both ionic and covalent bonds in the compounds with ionic bond playing dominant roles. The calculated band structure and DOS profiles indicate metallic character of XIr3 compounds. It is also found from the DOS profile that the Ir 5d-states dominate near the Fermi level. Unlike the significant anisotropy observed in elastic and thermal properties, all the optical constants of XIr3 compounds exhibit almost isotropic behavior. The optical parameters’ profiles correspond very well with the electronic band structure and DOS features. We have estimated the superconducting transition temperature (Tc) of XIr3 compounds in this work. The calculated values of Tc for LaIr3 and ThIr3 compounds are 4.91 K and 5.01 K, respectively. We have compared and contrasted all the physical properties of XIr3 (X = La, Th) compounds in this study.

Smart management of the wheat crop requires understanding the various variables affecting crop quality and quantity. The use of remote sensing data contributes to improve the application of precision agriculture (PA).The current paper aims to evaluate the efficiency of remote sensing in monitoring wheat growth and enhance the management practices. Three cultivation technologies for winter wheat were implemented: basic (CT1), intensive (CT2), and highly intensive (CT3) were investigated. Sentinel-2 with a resolution of 10 m was used to monitor the change in wheat growth under different management systems during 2019. The following variables: yield quantity, grain quality (measured protein and gluten), in addition, five vegetation indices: Soil Adjusted Vegetation Index (SAVI), Enhanced Vegetation Index (EVI), Normalized Difference Vegetation Index (NDVI),Green Chlorophyll Index (GCI), Green Leaf Index (GLI) were retrieved during the growing season. The results showed that, GCI has the highest performance in predicting crop yield where r was 0.98. In addition, the SAVI and NDVI have the same performance; r was 0.96 for both protein and gluten contents. The yield production of CT3 has increased by 3 t/ha, in addition, the grain quality was superior compared to the CT1. The economic efficiency results showed that the CT3 was the most profitable for Moscovskaya 40 variety (WV1) with 2,72 Payback. For Nemchinovskaya 17 variety (WV2), the most profitable cultivation technology was the CT1 and CT2 with 2,44 Payback, and for the new variety Nemchinovskaya 85, the CT2 was the most profitable with the Payback of 3,03. Finally, remote sensing shows the spatial variation in crop growth, which enhances crop management to achieve optimal production in terms of quantity and quality.

In this study, an attempt has been made to explore the physical characteristics of Sc2Al2C3, including a first-time investigation of elastic anisotropy, thermodynamic, and optical properties. The physical properties of other Sc-Al-C systems have also been compared. The elastic constants and phonon dispersion curves confirmed the mechanical and dynamical stabilities of Sc2Al2C3, and the estimated lattice parameters agreed well with the experimental results. The semiconducting behavior of Sc2Al2C3 has been confirmed by band structure and density of states calculations. An in-depth discussion is presented on the melting point, minimum thermal conductivity, and the Debye temperature. The Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) are also computed from the phonon density of states. The dielectric constant, refractive index, absorption coefficient, photoconductivity, reflectivity, and loss function have also been calculated for the first time. Band structure calculations and optical parameters complement each other very well.

We have looked into the structural, mechanical, optoelectronic, superconducting state and thermophysical aspects of intermetallic compound Zr3Ir using the density functional theory (DFT). Many of the physical properties, including detailed direction dependent mechanical properties, hardness in different formalisms, Fermi surface topology, machinability, fracture toughness, optical properties, chemical bonding nature, and charge density distributions, are being investigated for the first time. According to this study, Zr3Ir exhibits ductile features, high machinability, significant metallic bonding, a small Vickers hardness with low Debye temperature, and a modest level of elastic anisotropy. Ductility, high level of machinability, and damage tolerance make this compound attractive for engineering applications. The mechanical and dynamical stabilities of Zr3Ir have been confirmed. The metallic nature of Zr3Ir is seen in the electronic band structures with a high electronic energy density of states at the Fermi level. The bonding nature has been explored by the charge density mapping and bond population analysis. Zr3Ir shows a remarkable electronic stability, as confirmed by the presence of a pseudogap in the electronic energy density of states at the Fermi level which is situated between the bonding and antibonding states. Energy dependent optical parameters show very good agreement with the electronic density of states profile. The reflectivity spectra reveal that Zr3Ir is a good reflector in the infrared and near-visible regions. Zr3Ir is an excellent ultra-violet (UV) radiation absorber. High refractive index at visible photon energies indicates that Zr3Ir could be used to improve the visual aspects of electronic displays. All the optical constants exhibit a moderate degree of anisotropy. Zr3Ir has a moderate melting point, high damage tolerance, and very low minimum thermal conductivity. The thermomechanical characteristics of Zr3Ir reveal that it is a potential thermal barrier coating material. The superconducting state parameters of Zr3Ir are also explored.

This study explored the physical properties of MAX phase borides, M2GaB (M = Sc, V, Nb, Ta), aided by the density functional theory (DFT) for the first time. The optimized lattice constants were obtained by minimizing the total energy. We checked the thermodynamic stability by computing the formation energies. We calculated the electronic band structure, density of states (DOS), and charge density mapping to reveal the electronic ground state and bonding nature. The computed stiffness constants (Cij) confirmed the mechanical stability of the investigated compounds. Young's modulus, shear modulus, bulk modulus, and Poison's ratio have been computed using Cij. We calculated the Pugh's ratio, Poisson's ratio, and Cauchy pressure to judge the ductility/brittleness. The Vickers hardness values were calculated. The anisotropic properties of M2GaB compounds were studied by the elastic moduli's directional projections and the anisotropy indices' calculations. We have discussed the acoustic behavior of the M2GaB phases. We have also investigated the Grüneisen parameter, the Debye temperature ϴD, the thermal expansion coefficient, the specific heat, the Helmholtz free energy, the entropy, the internal energy, and the lattice thermal conductivity (Kph) of these borides. To determine the suitability as thermal barrier coating (TBC) materials or whether the compounds are appropriate for high-temperature applications, the minimum thermal conductivity (Kmin) and melting temperature (Tm) have also been calculated. The compounds' dynamical stability was examined using the phonon dispersion curves. The optical parameters have been studied, and it has been found that these compounds are compatible as coating materials to reduce solar heating.

The M2GaB (M = Ti, Zr, Mo, Hf) MAX phase borides were investigated in the present study. We have calculated the fracture toughness, brittleness index, acoustic behavior, Mulliken bond-overlap population, theoretical Vickers hardness, f-index, phonon, charge density mapping, and thermodynamic and optical properties via the density functional theory (DFT). To assess the correctness of our calculations, we revisit the lattice constants, band structure, density of states, elastic constants, mechanical stabilities, and dynamic stabilities. We studied these compounds' formation energies, elastic constants Cij, and phonon dispersion curves to evaluate their chemical, mechanical, and dynamical stability. The fracture toughness and brittleness index were calculated to determine the crack extension and damage tolerance resistance. The acoustic behavior was also studied. The Mulliken bond population was used to investigate the distribution of electrons between the atomic bonds and to determine the compounds' Vickers hardness. Calculating the f-index, we analyzed the bonding strength along the a- and c-directions. The essential thermodynamic properties of M2GaB (M = Ti, Zr, Mo, Hf) compounds were calculated to understand their thermal response at different temperatures and possible applications. Finally, we computed the optical properties to assess their electronic response to the incident photon and predict the possibility of their use.

In this paper, we have presented a comprehensive study of the physical properties of Kagome superconductor CsV3Sb5 using the density functional theory (DFT) methodology. The structural, mechanical, electronic properties (band structure, electronic energy density of states, Fermi surface, and charge density distribution), atomic bonding, hardness, thermodynamics, optical properties, and their pressure dependences have been investigated systematically at different pressures. The calculated ground state lattice parameters and volume are in excellent agreement with available experimental results. The estimated single-crystal elastic constants ensured the mechanical stability of the compound, whereas phonon spectra endorse dynamical stability at zero pressure. The electronic band structure, density of states, and optical properties confirmed the metallic feature. The Pugh ratio and Poisson’s ratio of the compound under study revealed the softness/ductility. The hardness of CsV3Sb5, estimated using several formulae, is quite low while the machinability index predicted good machinability with excellent lubricating properties. The compound shows tendency towards structural instability at a pressure around 18 GPa. The optical constants have also been studied to correlate them with electronic properties (band structure) and predict the possible applications of this compound. Both the mechanical and optical properties show directional anisotropy. CsV3Sb5 is predicted to be an efficient absorber of ultraviolet radiation. The compound is also an efficient reflector of visible light. The superconducting transition in CsV3Sb5 has been revisited following prior studies.

Non-centrosymmetric germanide-based superconductors have recently attracted particular attention because of their unconventional physical properties. In the present study, we comprehensively investigated the structural and hitherto unexplored electronic, optical, mechanical, thermal, and superconducting state properties of germanide-based superconductors, MGe2 (M = V, Nb, and Ta), using the density functional theory. The obtained lattice parameters and accordingly the volume of the unit cells agree very well with the earlier reported values, indicating the high reliability of the physical properties studied. All the compounds studied herein are dynamically and mechanically stable. The compounds are brittle (ranked: NbGe2 50% for all these compounds, demonstrating their potential for application as coating material to reduce heating from incident electromagnetic radiation. Based on the results obtained for thermal properties and comparison with benchmark system, Y4Al12O9 and some other predicted compounds, the titled compounds could also be used as thermal barrier coating materials. Some important parameters for the understanding of the superconducting behavior, such as the Coulomb pseudopotential, London penetration depth, coherence depth, Debye temperature, electron-phonon coupling constant, and Ginzburg-Landau parameter, are also estimated, and the results obtained support that the NbGe2and TaGe2 compounds should be categorized as a type-2 superconductors.

The aim of this work was to carry out an experimental study along with kinetic and thermodynamic analysis for the toluene disproportionation reaction under actual industrial operating conditions. The toluene disproportionation reaction was carried out under pressurized hydrogen and over three different ZSM-5 based catalysts, namely, ZSM-5, 3%Mo on ZSM-5, and 3%Mo on ZSM-5/Mordenite. The influence of reaction temperature and catalyst composition on conversion and product distribution was investigated. A network of reversible reactions and elementary rate laws reflecting the product distribution, including xylene isomers and other products, were proposed and validated using the obtained experimental data. The thermodynamic parameters were estimated using a chemical process simulation package (Aspen HYSYS), while numerical and statistical methods were used to estimate the kinetic parameters. A notable agreement between the model predictions and the experimental data was obtained. The Mo-impregnated, mordenite-containing catalyst (3%Mo on ZSM-5/Mordenite) was found to be the most active catalyst, presumably due to the additional metallic-active sites that were readily accessible through the mordenite's large pores compared to the plain ZSM-5 catalyst. In addition, the most active catalyst was found to have the lowest activation energies and lead to conversions that were limited thermodynamically.

The combination of ceramic and metallic properties of the MAX phases makes them attractive for numerous technological applications. The very recent experimental synthesis of the Zn-based MAX phase Ti3ZnC2 is an important addition to the MAX phase family as it further expands the diversity of physical characteristics of this family. Here we have employed density functional theory (DFT) calculations to investigate the structural, electronic, mechanical, lattice dynamic and thermal properties of Ti3ZnC2 for comparison with existing Ti3AC2 phases. Additional transition metal Zn at A-site in newly synthesized Ti3ZnC2 reduces most of the elastic constants and moduli as well as the Debye temperature and thermal conductivity. All the Ti3AC2 phases have the potential to be etched into 2D MXenes with great possibility for Ti3ZnC2. Ti3ZnC2 is highly anisotropic in the Ti3AC2 MAX phase family.

In this paper, a first-principles study of the newly known MAX phase borides Zr2AB2 (A = In, Tl) has been carried out. The stiffness constants, elastic moduli, mechanical anisotropy, thermal and optical properties are investigated for the first time. The structural lattice parameters are found to be consistent with previous study. The dynamical and mechanical stability of the titled compounds have been checked. Fundamental insights into the stiffness constants, elastic moduli, hardness parameters, brittleness and anisotropy indices are presented. The variation of these mechanical properties is explained based on the Mulliken population analysis and charge density mapping (CDM). The metallic nature and anisotropy in conductivity has been confirmed from the electronic band structure. The analysis of DOS revealed the dominant contribution from Zr-d orbitals to the conductivity. The higher values of ΘD and Tm, and lower value of Kmin for Zr2AB2 (A = In, Tl) compared to those of Zr2AC (A = In, Tl) suggest enhanced thermal properties of the compounds under study for practical applications. Besides, the specific heat capacities (Cv, Cp), thermal expansion coefficient, and different thermodynamic potential functions have been calculated. The technologically important optical constants have been studied with an intention to reveal their possible relevance for application purposes. The reflectivity spectra revealed the applicability of Zr2AB2 (A = In, Tl) as cover materials to diminish the solar heating. The studied physical properties of Zr2AB2 (A = In, Tl) are compared with those of other relevant 212 and 211 MAX phase nanolaminates.

In this article, a detailed study of the recently synthesized MAX phase borides M2SB (M = Zr, Hf and Nb) has been performed via first principles technique. Investigation of mechanical properties, elastic anisotropy, optical properties, dynamical stability and thermal properties are considered for the first time. The estimated values of stiffness constants and elastic moduli are found in good agreement with available results. The Vickers hardness is also calculated using Mulliken population analysis. The electronic density of states and charge density mapping are used to explain the variation of stiffness constants, elastic moduli and hardness parameters among the studied ternary borides. The Nb2SB compound is found to show the best combination of mechanical properties. Mixture of covalent and ionic bonding within these borides is explained using Mulliken population analysis. The direction dependent values of Young's modulus, compressibility, shear modulus and Poisson's ratio are visualized by 2D and 3D representations and different anisotropic factors are calculated. The important optical constants are calculated and analyzed. The metallic nature of the studied borides is confirmed from the density of states (DOS) and optical properties. The reflectivity spectra reveal the potential use of Zr2SB as coating materials to diminish solar heating. The studied borides are dynamically stable as confirmed from the phonon dispersion curves. The characteristic thermodynamic properties have also been calculated and analyzed. The physical properties of corresponding 211 MAX phase carbides are also calculated for comparison with those of the titled ternary borides.

Liquid Composite Molding (LCM) is one of the widely used manufacturing techniques for high performance composite parts. In a simple LCM process, a pressurized liquid resin is injected inside a mold containing fibrous reinforcements. In order to create quality components using LCM processes, reinforcement characterization such as permeability and compaction response need to be performed fast and accurately. In this work, a micro CT based experimental-numerical reinforcement compaction and permeability characterization framework has been proposed which can potentially reduce process characterization cost by lowering material consumption and labor time and effort. The framework is non-destructive in nature and uses a miniaturized compression stage that can be housed in an X-ray computed tomography (XCT) system. This in-situ XCT experimental set-up is used to acquire the stress relaxation curve and XCT images of the reinforcement internal structure at multiple fiber volume fractions which are then converted into digital twins of the reinforcements. The virtual permeability of the reinforcement digital twin is computed through numerical flow simulations using realistic voxel models extracted from the stack of XCT images. The proposed approach has the capability of obtaining a plethora of information about the preform including, compaction response, statistical measurements of the internal preform geometry, and voxel models for numerical simulations. The methodology has been successfully demonstrated using two carbon fiber reinforcements with 3D woven architecture. The virtual permeability predictions were benchmarked against experimentally measured values, and were found to be in excellent agreement with the experimental data.

The effect of chemical fertilizer (NK) and humic acid on top length, root length, root diameter, leaf area per plant, top fresh & dry weight and root fresh & dry weight of fodder beet (Beta vulgaris L. c.v voroshinger) was carried out in the Experimental Farm of Agriculture Faculty, South Valley University at Qena during the two seasons of 2016/2017 and 2017/2018 on sandy soil. A field experiment was conducted using a randomized complete block design in split- plots arrangement with three replications. Humic acid treatments were arranged in main plots while, fertilization treatments (NK) were allocated in sub-plots. The highest mean values of most previous traits were obtained from fodder beet plants which were supplemented by soil application of humic acid and 90kg N+100kg K2O /fed. (H1F9). Based on these results, it is recommended to adding humic acid on soil and fertilization with NK by 90 Kg N + 100 kg K2O per Feddan for fodder beet under similar soil and climate conditions.

Scientific endeavor for tailoring properties of functional materials offers a significant urge to material scientists. The driving force is to facilitate the current understanding that may create new pathway to alternative materials. BiFeO3 is inherently multiferroic and its exploitation for applications in diversified fields are still required extensive investigations in different perspectives. In this context, we synthesized new Bi0.85Gd0.15Fe1−xCrxO3 multiferroics prepared by wet chemical method using high purity metal salts. We mainly focused on the investigation of dielectric properties, ac electrical conductivity and complex electrical modulus of the synthesized materials. Crystallographic measurements confirmed its rhombohedral structure which gradually transforms towards orthorhombic structure with increasing Cr dopants. The grain size of the synthesized samples was found to vary from 68 to 22 nm depending on doping concentration. Dielectric properties of sintered samples were studied in the frequency range of 100 Hz–1 MHz. Frequency dependent dielectric constant has shown to display dielectric dispersion behavior. At higher frequencies (⩾105 Hz), due only to electronic and ionic polarizations the dielectric constant has shown to be independent of frequency. Complex impedance showed a semicircular arc due to the dominant grain boundary resistance and the electric modulus confirms the existence of electrical relaxation. The AC conductivity (σAC) has shown to obey a power law. Obtained improved properties suggested that the synthesized Bi0.85Gd0.15Fe1−xCrxO3 ceramic by partial substitution of A and B sites by Gd3+ and Cr3+ shows added advantage in application over the pure BiFeO3 counterpart. Keywords: Functional ceramic, Dielectric, GB resistance, Polaron hopping, Annealing, Nanoparticles

We have studied the physical properties of M2InC (M = Zr, Hf and Ta) MAX phases ternary carbides using density functional theory (DFT) methodology. The structural, elastic and electronic properties are revisited (and found to be in good agreement with recently reported results). The charge density distribution, Fermi surface features, Vickers hardness, dynamical stability, thermodynamics and optical properties have been investigated for the first time. The calculated single crystal elastic constants and phonon dispersion curves endorse the mechanical and dynamical stability of all the compounds under study. The calculated single crystal elastic constants Cij and polycrystalline elastic constants are found to increase with increasing atomic number of M species (M = Zr, Hf and Ta). The values of Pugh ratio and Poisson’s ratio revealed the brittleness of the compounds under study associated with strong directional covalent bond with a mixture of ionic contribution. Overlapping of conduction band and valence band at Fermi level notify the metallic nature of M2InC (M = Zr, Hf and Ta) MAX phases. Low values of Vicker hardness indicate the softness of the materials and easy machinability. The thermodynamic properties, such as the free energy, enthalpy, entropy, specific heat capacity and Debye temperature are evaluated using the phonon dispersion curves and a good correspondence is found with the characteristics of M atomic species. Major optical properties, e.g., dielectric functions, refractive index, photoconductivity, absorption coefficient, loss function and reflectivity are calculated and discussed in detail in this study. Keywords: MAX phase, M2InC (M = ZZr, Hf, Ta) compounds, Physical properties, First principles study, Phonon dispersion curve

Predominance of genotype G3P[8] rotavirus was revealed for children and adults with diarrhoea in north-central Bangladesh for a 1-year period from September 2018. The G3P[8] rotaviruses were phylogenetically close to recent Indian strains, having antigenic variation in VP7 and VP4 compared with old Bangladeshi strains. Keywords: Antigenic drift, Bangladesh, G3P[8], phylogenetic analysis, rotavirus

Thoroughly qualitative and quantitative topography, microstructure, splats formation and phases evaluation were made to understand carefully the behavior of plasma sprayed zirconia-ceria-yttria coatings processed under near optimum processing conditions. The study is focused on how to design and select the given property to predict the reliable data of plasma sprayed zirconia-20 wt% CeO2-3.6 wt% Y2O3. The processing and plasma spraying parameters were designed carefully to give a reliable clear evaluation of the microstructure. The results showed a heterogeneous microstructure in which melted, semimelted and unmelted particles were existed. The phases formed are consisted of nontranformable tetragonal phase (t') with small amount (less than 2 mole%) of monoclinic phase (m). The electron probe microanalysis (EPMA) suggests the intimate mixing between the binary systems of zirconia-ceria and zirconia-yttria during spraying. The Image J technique, SEM, EPMA, EDS and XRD/step scan XRD were used collectively to build up a clear picture on the solidification mechanism of the new plasma sprayed coating system.

This article reports the first-principles calculations of yet unexplored Mulliken bond population, Vickers hardness, thermodynamic and optical properties of MAX phases V2AC (A = Al, Ga). We have also revisited the structural and elastic properties of these phases in order to assess the reliability of our calculations. The temperature and pressure dependence of bulk modulus, Debye temperature, specific heats, and thermal expansion coefficient have been successfully estimated through the quasi-harmonic Debye model in the temperature range from 0 to 1000 K and the pressure range from 0 to 50 GPa. The optical properties such as the dielectric function, refractive index, photoconductivity, absorption coefficients, reflectivity and loss function are also evaluated for the first time. The reflectivity is found to be high which indicates that V2AC (A = Al, Ga) having the same characteristics could be good candidate materials to reduce solar heating up to ∼15 eV. Keywords: V2AC MAX phases, First-principles calculations, Elastic properties, Vickers hardness, Thermodynamic properties, Optical properties

Optimum sintering temperature (Ts) plays an important role in controlling densification and growth of grains which greatly affect the magnetic and electrical properties of polycrystalline materials. Y-substituted Mg-Zn [Mg0.5Zn0.5YxFe2−xO4 (0 ≤ x ≤ 0.05)] ferrites have been prepared by using conventional standard ceramic technique and were sintered between 1100 and 1300 °C in the steps of 50 °C. Characterizations of the samples have been done by X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM), dielectric and permeability measurements to find the suitable Ts. XRD data have been analyzed and the results confirmed the same information regarding phase analysis at different Ts. Further characterization of the samples, sintered at 1100 and 1150 °C, were not continued due to their low density and high porosity. FESEM images indicate the change in microstructure with Ts. The decrease (increase) of ac electrical resistivity with Ts (Y content) has been observed while the dielectric constant behaves in opposite manner. Impedance spectroscopy also exhibited similar trend as ac electrical resistivity. The initial permeability revealed the wide stability zone of frequency and different optimum Ts for different compositions. The ac resistivity values for the compositions have been found higher at 1200 °C, but the compositions have highest value of bulk density and permeability at other Ts. The effect of Ts on the physical properties (bulk density, porosity and permeability) of Y-substituted Mg0.5Zn0.5YxFe2−xO4 (0 ≤ x ≤ 0.05) ferrites elucidate that the optimum Ts should be of 1250 °C for x = 0.01, 0.02 and 0.03 while the Ts should be of 1300 °C for x = 0.04 and 0.05. Keywords: Y-substituted Mg-Zn ferrites, Bulk density, Ac resistivity, Dielectric constant, Impedance spectroscopy, Sintering temperature

The performance of dual chambered microbial fuel cell (MFC, Nafion 117, non-catalysed graphite electrodes) in concurrence with anodic pH microenvironment was evaluated based on bioelectricity generation from palm oil empty fruit bunch (EFB). Experiments were carried out at different anodic pH microenvironments (acidic (5), neutral (7) and alkaline (9)) using potassium permanganate catholytes with mixed consortia as anodic biocatalyst. In addition, power and microbial growth were also evaluated in order to connect the link between pH changes and MFC performance.

The core objective of this research was to determine the characteristics of oils, nutritional composition and antimicrobial activities of T. anguina and S. mahagoni seeds. Physicochemical characteristics of oils implied higher degree of unsaturation in T. anguina whereas, S. mahagoni oil contained appreciable level of unsaturation. Tri-acyl-glycerols and neutral lipids were found to be most abounded components recorded to 86.2 and 91.3% for T. anguina and 87.0 and 89.4% for S. mahagoni, respectively. GLC analysis showed the presence of fatty acids from series C16:0 to C18:3 for T. anguina and C16:0 to C20:0 for S. mahagoni in which principal fatty acids accounted as punicic (45.1%) in T. anguina and linoleic (30.1%) in S. mahagoni seed oils. Of the major energy producing nutrients, the seed samples contained large amounts of lipid (36.1% in T. anguina and 57.9% in S. mahagoni) and protein (20.9% in T. anguina and 13.0% in S. mahagoni) and potentially useful amounts of other nutrients. The knowledge from the nutritional analysis could be important to its appropriate industrial use and for improvement in the nutritional value. Assessment of the anti-microbial studies reported herein revealed the crude extracts of T. anguina and S. mahagoni seeds were not significantly inhibition against most of the tested bacteria and fungi. This study may lead to further ethno-pharmacognostic investigations to identify new compounds with therapeutic promise.

A variables range of conducting polyaniline (PANI) nanocomposites hosted by polyvinyl alcohol (PVA) in a form of film has been prepared by using -irradiation technique to Aniline hydrochloride (AniHCl)/PVA composites. The conductivity of the film showed consequence increase following the radiation dose from 10 to 50 kGy for each different concentration of the monomer blend AniHCl in PVA matrix which have exponential relation. The maximum achieved dc conductivity (0) was 10-1 (S/m) at high concentration of AniHCl and 50 kGy radiation dose, as being studied by LCR-meter. The composite films structure has also been studied by Raman spectroscope, which reveals that there is a new chemical bond structure as imines group of the form C=N (polarons) species has been formed by radiation and giving rise to Raman shift at 1637 cm-1. The intensity of Polarons was also being increased exponentially following the radiation dose leading to increase of polyaniline conductivity. Moreover the morphological structure of the films were scanned by Scanning Electron Microscopy SEM, which intern reveals that the composite film is composed of polyaniline nanoparticles in the range size of 100 nm.

Aucune trématodose n'est actuellement connue à Mayotte malgré les liens historiques de celle île avec sa voisine Madagascar où l'incidence de ces affections est importante. Aucun hôte intermédiaire n'y avait été décrit dans les études précédentes. Un inventaire des mollusques d'eau douce a été réalisé de 1985 à 1988 dans 53 stations durant les saisons humide et chaude : 3940 gastéropodes, appartenant à 8 espèces différentes, ont été récoltés. Seule la présence de Lymnaea natalensis constitue une nouveauté à Mayotte, portant à 14 le nombre d'espèces. Son rôle dans le cycle de transmission de Fasciola gigantica est connu, en particulier à Madagascar. L'intérêt du contrôle vétérinaire des importations de bovins peut être ainsi souligné.

Nowadays, the advancement of heat transmission for the heat exchanger device is an important field of research for many researchers. In this work, a numerical study has been conducted to investigate the thermal performance of a mixed convective flow through the octagonal heat exchanger covered by hybrid nanofluid (Cu-TiO2-H2O). A magnetic field has been introduced inside the cavity to investigate the mixed convective hydrodynamics heat flow characteristics. The nanofluid cores absorb/release energy to manage heat transmission by increasing or decreasing inside the cavity domain as the host fluid and dispersed hybrid nanofluid circulate within the cavity. After transforming the governing equations into a generalized, non-dimensional formulation, the finite element approach is utilized to solve the associated equations. Additionally, response surface methodology is also applied to test the responses of the associated factors. Heat transport was examined in relation to the effects of nanofluids fusion temperature, boundary wall properties, Reynolds number, Hartmann number and nanoparticle volume fractions. The outcomes of this study are analysed by measuring streamline profiles, isotherms, average Nusselt number, velocity profile, and 2D and 3D response surfaces of the computational domain. The underlying flow controlling parameters for instance Reynolds number (10 ≤ Re ≤ 200), Hartmann number (0 ≤ Ha ≤100), and nanoparticle volume fractions (0 ≤ ϕ ≤ 0.1), the influences have been considered. The findings also reveal that the thermal performance is being boosted due to augmentation of Re and ϕ, but reverse behavior is noticed for Ha. Furthermore, the response surfaces obtained from response surfaces methodology express that the Re and ϕ have shown positive influence, and Ha has shown negative influence on Nuav. Utilizing a hybrid nanofluid of Cu-TiO2-H2O increases the heat transfer capacity of water to 25.75 %. Moreover, the findings could guide to design of a mixed convective heat exchanger for industrial purposes.