X-ray Diffractograms Research Articles

Structural and optical characterization of semiconducting lithium modified zinc borate glassy system for UV band reject filter

The amalgamation of different compositions of 20ZnO.(80-x)B2O3.xLi2O (x = 10, 20, 30 and 40) glasses have been performed via well-known melt quenching technique. The absence of any sharp peak in X-ray Diffractograms confirms short range order i.e. amorphous nature of selected glass series. Calculations of density (ρ) have been done using the Archimedes principle and further different physical parameters such as molar volume (Vm), crystalline volume (Vc), bond density (nb), electronegativity difference (∆x), bond ionicity (Ib), boron-boron distance (<dB-B>), polaron radius (Rp), lithium ion concentration (N), lithium interionic separation (Ri), and lithium yield field strength (F) were calculated and found to be in correlation. Structural modifications occurring in the glass network with the addition of lithium oxide have been studied by identifying and careful assignment of structural groups present in the IR and Raman spectra on the basis of literature survey. The FTIR and Raman analysis revealed that the neutral triangular structural units (BØ3) transforms into charged tetrahedral borate units (BØ4−) which signifies the compactness of the glass network with enhancement in lithium concentration. The optical transmission studies revealed that glass composition 20ZnO.40B2O3.40Li2O acts as a UV band reject filter for wavelengths ranging from (247-323)nm whereas it acts as a transparent window with ∼80% transparency in the visible region. These optical features make glass composition 20ZnO.40B2O3.40Li2O suitable for radiation protection shields and may be used as an UV protective coating on window/sun glasses. The optical absorption spectrum has been in the light of the Mott and Davis model, Hydrogenic Excitonic model and modified Urbach energy model for extracting different optical parameters.

Extraction optimization and molecular dynamic simulation of cellulose nanocrystals obtained from bean forage

The structural, energetic, and mechanical characteristics of cellulose were evaluated through molecular dynamic simulation on atomic scale in view of different applications. This research standardized the processing variables for the extraction of cellulose nanocrystals obtained from bean forage; the optimal conditions for the alkaline and bleaching treatments were: NaOH 1.75% w/w for 8.5 h with a bleaching time of 1 h at 70 °C with a yield of 25.51%; for the acid treatment the optimal conditions obtained were: H2SO4 at 55% for 30 min at 40 °C; in this case, the optimization was carried out with two responses: yield (60.68%) and crystallinity index (49.36%). The raw material was chemically characterized showing a cellulose content of 45.78 ± 0.888% wt. cellulose, 10.73 ± 0.732% wt. hemicellulose, 5.09 ± 0.753% wt. lignin, and other components. X-ray diffraction indicated changes in the diffraction patterns corresponding to the crystalline and amorphous areas of the cellulose. The percentages of crystallinity obtained with the optimal conditions were: 40.39% after the alkaline treatment, 42.02% after the bleaching treatment, and 49.36% after the acid treatment. Finally, the structure and molecular dynamics of cellulose nanocrystals obtained from bean forage created with Materials Studio 8.0 program were evaluated, in which geometric optimization was carried out applying the Quasi-Newton BFGS method. X-ray diffractograms generated by the program were compared against those obtained experimentally, validating the virtual structure of the nanocrystals by obtaining a similarity of 86%, which would allow exploratory research using molecular dynamics to find possible applications.

Superior photocatalytic and electrochemical activity of novel WS2/PANI nanocomposite for the degradation and detection of pollutants: Antibiotic, heavy metal ions, and dyes

The untreated discharge of noxious pollutants is drawing worldwide concern due to their irretrievable damage to the environment. Especially, pharmaceutical waste has been identified as an emerging pollutant due to its increased demand and untreated discharge into the water bodies. The elimination and detection of such persistent contaminants from wastewater have proven to be a difficult endeavor due to the constraints imposed by the materials and technologies. Therefore, in the present work “free two birds with one key” strategy was implemented to develop a novel visible-light-driven photocatalyst and the electrochemical sensor using WS2/PANI nanocomposite for the degradation and detection. The synthesized WS2/PANI nanocomposite was systematically characterized with a High-resolution transmission electron microscope (HRTEM) and Field emission scanning electron microscope (FESEM) for morphology, Energy-dispersive X-ray (EDX) spectroscopy for elemental analysis, X-ray diffractogram (XRD) for orientation planes, Fourier transform infrared (FTIR) spectroscopy for functional groups and bonds, Zeta potential for the surface charge, Tauc's plot for bandgap analysis, Photoluminescence (PL) spectroscopy study for defects, Time-Resolved Photoluminescence (TRPL) for photogenerated charge carriers, BET for surface parameters and Liquid chromatography-mass spectrometry (LC-MS) for intermediate photodegradation products. The WS2/PANI nanocomposite displayed excellent activity for the photodegradation of antibiotic (nitrofurantoin: NFT, 95%) along with the detection and also degraded textile dye (Methyl orange: MO, 97%), and heavy metal ion (Cr(VI), 99%) with good reusability up to 4 cycles. The superior photocatalytic activity demonstrated by WS2/PANI attributes to its remarkable properties such as a high photoinduced charge separation (5.76 ns) and visible-light-driven bandgap (2.6 eV). A scavenger experiment was also performed to confirm the formation of photoinduced reactive oxygen species (•OH and O2•−). In addition to photocatalytic degradation, WS2/PANI nanocomposite portrayed excellent electrochemical detection of NFT with a low limit of detection (LOD) of 0.01 µM and a wide linear range of 500–0.01 µM.

Synthesis and Evaluation of Finasteride-Loaded HPMC-Based Nanogels for Transdermal Delivery: A Versatile Nanoscopic Platform.

Herein, we report nanogels comprising diverse feed ratio of polymer hydroxypropyl methylcellulose (HPMC), monomer acrylic acid (AA), and cross-linker methylene bisacrylamide (MBA) fabricated for transdermal delivery of finasteride (FIN). Free radical solution polymerization method with subsequent condensation was employed for the synthesis using ammonium per sulfate (APS) and sodium hydrogen sulfite (SHS) as initiators. Carbopol-940 gel (CG) was formulated as assisting platform to deliver FIN nanogels transdermally. Developed formulations were evaluated by several in vitro, ex vivo, and in vivo parameters such as particle size and charge distribution analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffractogram (XRD), rheological testing, in vitro swelling and drug release, and ex vivo skin permeation, irritation, and toxicity assessment. The results endorsed the nanogel formation (117.3 ± 29.113 nm), and the impact of synthesizing method was signified by high yield of nanogels (≈91%). Efficient response for in vitro swelling and FIN release was revealed at pH 5.5 and 7.4. Skin irritation and toxicity assessment ensured the biocompatibility of prepared nanocomposites. On the basis of the results obtained, it can be concluded that the developed nanogels were stable with excellent drug permeation profile across skin.

Two Routes for Sonochemical Synthesis of Pt-Nanoparticles

To improve the performance of electrochemical hydrogen conversion devices such as electrolyzers and fuel cells, more efficient catalyst materials must be developed. As the available surface area is key to the performance of a catalyst, high surface area nanoparticles are required. The synthesis of such nanostructured catalysts is predominantly based on chemical reduction with a strong reducing agent like sodium borohydride. However, it is difficult to achieve the desired particle properties without the use of additives such as surfactants or stabilizers.In order to achieve more control over the nucleation and growth stage of the nanoparticles, we can replace the chemical reduction route by sonochemical reduction. In sonochemistry, high power ultrasound is used to generate reducing radicals which allow for controlled reduction of metal precursors. The radical generation rate is strongly linked to the nucleation and growth of the resulting nanoparticles and can easily be tuned by adjusting the ultrasonic frequency and power. Ultrasound therefore offers an easy and reproducible way of tuning the size of nanoparticles.In our work we have compared the size, shape, and morphology of Pt-nanoparticles synthesized sonochemically and with chemical reduction to see if the sonochemical route indeed offers better control during nucleation and growth. TEM-images along with X-ray diffractograms revealed that the sonochemical route gives smaller and more monodisperse particles compared to chemical reduction. In addition, the particle shape was found to be spherical with the sonochemical route, whereas chemical reduction resulted in many different shapes. The better and easier control over synthesis parameters exhibited by the sonochemical route can therefore be utilized to produce nanoparticles of very similar physical properties. We also showed that the catalytic properties of these nanoparticles towards hydrogen evolution were very similar further strengthening the sonochemical route when it comes to development of catalyst materials.A comparison between high frequency (408 kHz) and low frequency (20 kHz) ultrasound was also made to determine the impact of the higher mechanical effects expected at lower frequencies. No significant differences in particle size and morphology were found, but agglomerate sizes were found to decrease at lower frequencies. In addition, it was found that extensive probe erosion occurs at 20 kHz resulting in contamination of the nanoparticle solution. In fact, it was shown that the eroded particles act as nucleation sites for Pt-nanoparticles and increased reduction rates were observed. No such particle erosion happened at higher frequencies which led us to conclude that direct sonication at low ultrasonic frequencies in general must be avoided to prevent contamination of your system. This is important in all applications of low frequency (20 kHz) ultrasound, whether it be sonochemistry, dispersion of colloids, or ink preparation for electrochemical characterization.

Pasting Properties of Various Waxy Rice Flours: Effect of α-Amylase Activity, Protein, and Amylopectin

Waxy rice has a long history of being cultivated and consumed in China. In this study, the effect of different factors including α-amylase activity, protein, and amylopectin structure on the pasting properties of four waxy rice varieties were investigated. Rice flours were divided into four groups (Vietnam indica (VI), Jiangxi indica (JI), Anhui japonica (AJ), and Dongbei japonica (DJ) group) and treated with AgNO3 solution, DL-dithiothreitol (DTT), or protease (n = 3). Results suggested that both α-amylase activity and protein significantly decrease the pasting viscosity of waxy rice flours. Chain length distribution of amylopectin as measured by high performance ion exchange chromatography (HPAEC-PAD) showed that starch with a higher ratio of short chain leads to a higher pasting viscosity. X-Ray diffractograms showed that the crystal type of all the four varieties of rice starches were characteristic A-type. Relative crystallinity of each rice starch was further calculated, and higher crystallization resulted in a higher viscosity. Our study would provide a fundamental knowledge of the relationship between different factors and waxy starch pasting properties, as well as be a reference for controlling the quality of waxy rice starch-based food products.

Mineralogical analysis of rock dust for remineralization of soil intended for pasture

The objective of this study was to verify the effects of rock dust on the soil of an area destined for pasture. Mineralogical analysis of the rock dust was performed using X-ray diffraction, and the major oxides and minor elements were analyzed using X-ray fluorescence. The soil samples were analyzed according to PROFERT-MG. The following were identified from the X-ray diffractogram of the total rock powder: quartz (43.66%), albite (38.10%), microcline (15.30%), and muscovite (1.80%). Regarding the major elements, SiO2 (81.92%), Al2O3 (11.04%), and Na2O (3.86%) were predominant, and an important amount of K2O (2.61%) was present. In the chemical characterization of the soil, an increase in the levels of P, K, Ca, Mg, Sb, t, V, organic matter, and organic carbon were observed with the addition of rock dust. A comparison of the chemical analysis results with the CONAMA quality reference values indicated that the rock dust sample had acceptable levels with respect to the quality reference for all analyzed heavy metals. In a comparative analysis with MAPA's Normative Instruction No. 5/2016, it was found that rock dust does not fully comply with the minimum requirements of the legislation. In full compliance with the IN from chemical analysis, it had a minimum required content of at least 1% for K2O. Preliminary studies have indicated that the application of this material as a remineralizer has potential, mainly in relation to the supply of K2O. However, physical adjustments are required in the beneficiation process to comply with the standards.

Investigation of the structure transformation effect of ion-exchange membranes on a separation processes efficiency of technological solutions and an ecological safety of food production enterprises

A membrane separation of solutions, along with other purification methods, plays an important role in the effective and ecological safety of food production enterprises and is used for softening and demineralization of water, separation, concentration and purification of technological solutions, as well as for other processes. An important problem of membrane and electromembrane separation methods is to increase the used membrane selectivity. Therefore, the aim of this work was to study the structure transformation effect of ion-exchange membranes on a separation processes efficiency of technological solutions and an ecological safety of food production enterprises using the methods of X-ray diffraction analysis and differential scanning calorimetry (DSC). The analysis of the calculated values of crystallinity degree (CD) by X-ray diffractograms allowed us to identify the different effect of water saturation on the studied membranes. The structure of their material changes, which in turn affects the transport characteristics of the membranes, the efficiency of separation and, ultimately, the environmental ecological safety food enterprises. The cation-exchange membrane MK-40L was characterized by an increase in CD by 5.83%, and the anion exchange membrane MA-41P on the contrary was characterized by a decrease in CD by 5.87%. The crystallite sizes were distributed in the range of 0.096-0.345 nm for the MA-41P membrane and 0.096-0.193 nm for the MK-40L membrane. During thermal studies by DSC one endothermic and exothermic sections were revealed on the obtained curves in the temperature range of 30-202 and 202-498 °C for the MK-40L membrane and 30-223 °C and 223-498 °C for the MA-41P membrane, respectively. The endothermic sections of the curves were characterized by one endothermic peak. Four or five pronounced exothermic peaks were registered on the exothermic sections. At the same time, the MK-40L membrane was characterized by more intense peaks in a water-saturated sample and the MA-41P membrane in the dry one.

Leveraging computational thermodynamics to guide SiC-ZrC chemical vapor deposition process development

Using the CALPHAD approach to understand zirconium carbide deposition, a series of phase equilibria were calculated from a custom thermodynamic database based on a literature source, and the equilibria were used to explore the potential chemical vapor deposition (CVD) processing space in the ZrCl4-CH3SiCl3-CH4-H2 system as a function of pressure, temperature, and gas composition. Several gas ratios were considered. At a given ZrCl4:CH3SiCl3 ratio within the range studied, the most important factor was found to be the ratios of CH4:ZrCl4, wherein the nature of the composition – carbide vs. silicide – could be controlled. A pure binary composition of ZrC and SiC is expected to form by increasing the initial amount of methane and decreasing the amount of hydrogen from values predicted purely based on thermodynamic equilibrium. Rietveld analysis of the x-ray diffractograms from corresponding experimental depositions confirmed that increasing the CH4:ZrCl4 ratio increased the fraction of carbon-containing species (SiC, ZrC) and decreased the fraction of non-carbides (ZrSi, ZrSi2, etc.), as predicted from the CALPHAD results.

Photocatalytic Degradation of Polyethylene Microplastics and Disinfection of E. coli in Water over Fe- and Ag-Modified TiO2 Nanotubes

In this study, Fe- and Ag-modified TiO2 nanotubes were synthesized via an anodization method as photocatalysts for degradation of polyethylene microplastics and disinfection of Escherichia coli (E. coli). The anodization voltage, as well as the Fe3+ or Ag+ concentrations on TiO2 nanotubes were evaluated and correlated to their corresponding photocatalytic properties. TiO2 nanotubes were firstly synthesized by anodization of Ti plates in a glycerol-based electrolyte, followed by incorporation of either Fe or Ag via a Successive Ionic Layer Adsorption and Reaction (SILAR) method with Fe(NO3)3 and AgNO3 as Fe and Ag precursors, respectively. UV-Vis DRS shows that the addition of Fe or Ag on TiO2 nanotubes causes a redshift in the absorption spectra. The X-ray diffractograms indicate that, in the case of Fe-modified samples, Fe3+ was successfully incorporated into TiO2 lattice, while Ag scatters around the surface of the tubes as Ag and Ag2O nanoparticles. A microplastic degradation test was carried out for 90 mins inside a photoreactor with UVC illumination. TiO2 nanotubes that are anodized with a voltage of 30 V exhibit the best degradation results with 17.33% microplastic weight loss in 90 mins. Among the modified TiO2 nanotubes, 0.03 M Ag-TiO2 was the only one that surpassed the unmodified TiO2 in terms of microplastic degradation in the water, offering up to 18% microplastic weight loss in 90 min. In terms of E. coli disinfection, 0.03M Ag-TiO2 exhibit better performance than its unmodified counterpart, revealing 99.999% bactericidal activities in 10 mins. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Spectroscopic and electrical analysis of spray deposited copper oxide thin films

Copper Oxide (CuO) in thin film form is an excellent candidate for absorber layer in solar cells due to their adequate band gap, minimal cost, and large abundance. In this work, CuO thin films were grown on glass substrates by spray pyrolysis technique. The impact of substrate temperature and precursor concentration on the structural, morphological, optical, and electrical properties of the films were thoroughly investigated. The formation of polycrystalline tenorite phase CuO was confirmed by X-ray diffractogram. FESEM showed morphological homogeneity of the films and EDAX validated the presence of O and Cu in the samples. Spectrophotometric experiments revealed that CuO films exhibit a considerable absorption in the visible range, which gradually decreased after 800 nm. The film’s estimated band gap was near to the solar absorption band gap, indicating that they can be employed as absorber layers in solar cells. The formation of tenorite phase CuO was further confirmed by Raman analysis. The optical emission properties of the CuO films were studied by photoluminescence spectroscopy. X-ray Photoelectron Spectroscopy revealed the presence of Cu2O in minor fraction along with CuO. Hall measurements were done to study the electrical properties like resistivity, mobility, and carrier density.

Synthesis and characterization of polyurethane foam based on vegetable oil

This research shows the production and characterization of the polyurethane foam produced from moringa oil with low energy expenditure. Vegetable oil, polyol and the foam were characterized by hydroxyl, acid and Iodine index, Fourier Transform Infrared Spectroscopy (FTIR), 1H RMH spectra, Thermo gravimetric analysis (TG), Scanning Electrical Microscopy (SEM), X-Ray Diffractogram (XRD) and Mass Spectroscopy. The physical-chemical results showed the modified oil potential for the polyurethane formation reaction due to the hydroxyls index of 257.52 mg KOH g-1 and acidity of 2.38 mg KOH g-1. FTIR spectra showed the hydroxylation reactions and urethane groups formation in the oil by bands wich referring to hydroxyl groups and their NH groups superposition. Foam TG showed a degradation profile between 281 °C and 750 °C, losing half of its mass in temperatures higher than 400 °C. Micrographies showed that foam is composed by opened and closed cells, characteristic of semi-flexibility of the foam.

Synthesis, Characterization and Invivo Evaluation of Poly Sulfoxy Amine Grafted Xanthan Gum

Natural polymers are hydrophilic in nature, economic, chemically inert, easily available, biodegradable, and non-toxic. Following problems associated with the use of gums include uncontrolled rates of hydration, pH dependent solubility, thickening, drop in viscosity on storage, and the possibility of microbial contamination. Chemical modification of gums not only minimizes these drawbacks but also alter their physicochemical properties. Recently, researchers have been modifying properties of natural gums to explore its more applicability. Aim of the current study was to explore Xanthan gum’s applicability in mucoadhesive and other property by doing its Chemical modification. Sulfoxy amine modification of xanthan gum was carried out by reacting xanthan gum with thionyl chloride and further treated with ammonia. FTIR, elemental DSC, XRD and SEM were studied for confirmation of the modification. The modified xanthan gum showed improvement in the mucoadhesion, water uptake capacity, gelling property as well as viscosity as compared to unmodified xanthan gum. The results of X-ray diffraction study confirms the finding of DSC study. X-ray diffractogram confirmed XG is typical of amorphous substance while that of MXG is typical of crystalline substance with the characteristic peak appearing at 14.79, 25.66, 29.63 and 31.82 2θ. The 0.6% w/v of modified xanthan gum showed gelling property. The 0.6% w/v of modified Xanthan Gum showed gelling property where as Xanthan Gum required more than 1% w/v , it indicate that gelling property of Xanthan Gum has improved due to its modification. Mucoadhesive strength of modified xanthan gum was found to be 4±0.56 gm which is more than xanthan gum i.e. 1.5±0.94 gm. The ionic interactions may be taken place in between negatively charged mucus with cationic modified polymer and superior mucoadhesion can be achieved. Rapid and constant swelling behavior was observed by modified Xanthan gum. The SEM image of MXG showed that the grafting of Polysulfoxyamine onto XG brings about the change in the shape and size of the XG particles. The enhanced viscosity and gelling capacity of modified xanthan gum were also observed as compared to xanthan gum. In vivo acute toxicity study of Poly sulfoxy amine grafted xanthan gum was performed. The toxicological effects were observed in terms of mortality and expressed as LD50. Results of Acute toxicity study shows LD50 value was more than 2 gm/kg indicating the low toxicity. These findings proved that modified xanthan gum may be used as promising excipient in various drug delivery systems.&#x0D;

Tuning the structural, optical and magnetic properties of NiCuZn (Ni0.4Cu0.3Zn0.3Fe2O4) spinel ferrites by Nb2O5 additive

Ni0.4Cu0.3Zn0.3Fe2O4 ferrites with various compositions (0–5 wt. %) of Nb2O5 additive were synthesized by the sol-gel method with an aim to investigate their physical properties. The analysis of Rietveld refined X-ray diffractograms confirms formation of ferrites with a single-phase spinel structure having space group Fd3m. The result indicates that there is an enhancement in the lattice parameter values with increasing Nb2O5 content. The nanoparticles in the shapes of spheres and cubes with few agglomerations were evident from field emission scanning electron microscope images of ferrites. The elemental analysis from energy dispersive X-ray spectrum confirms the stoichiometric occurrence of constituent elements within the prepared samples. The Raman spectra confirm the cubic spinel structure of the prepared ferrite samples. The Fourier transform infra-red spectra confirm the superseding of Nb5+ ions in the unit cell of NiCuZn ferrite. Oxidation states of the elements within the ferrite were confirmed by means of X-ray photoelectron spectroscopy. The UV–Visible diffused reflectance spectroscopy results show that the band gap energy values were reduced with the increasing wt.% of Nb2O5 additive in the ferrite. The Nb2O5 additive reduces the saturation magnetization and coercivity of all the ferrite samples. The study reveals that the controlled amount of Nb2O5 additive in NiCuZn ferrite can tune the soft magnetic behavior and optical parameters of the ferrite at room temperature.

Magnetoelectric multiferroicity in a newly derived nanocomposite system of (Y0.97Al0.03FeO3)x((Bi0.5Na0.5)0.94Ba0.06TiO3)(1−x) [x = 0.3, 0.5

To derive a new multiferroic nanocomposite, Al-doped YFeO3 and Ba doped Bi0.5Na0.5TiO3 were considered as individual components. (Bi0.5Na0.5)0.94Ba0.06TiO3 was synthesized through sol-gel technique and successfully incorporated during the preparation of Y0.97Al0.03FeO3, where two different stoichiometric ratios (YAFO)0.3(BNBT)0.7 and (YAFO)0.5(BNBT)0.5 were considered. Rietveld refinement of X-ray diffractograms confirmed the desired phase formation without any impurity. Different useful structural parameters were evaluated from Rietveld analysis, which is helpful to explore the magnetoelectric behavior of both composites. FESEM micrographs showed spherical/ellipsoidal particles scattered uniformly obeying Gaussian distribution with an average grain size obtained as ∼45.3 nm for (YAFO)0.3(BNBT)0.7 and ∼47.2 for (YAFO)0.5(BNBT)0.5. EDAX spectra confirmed the absence of impurity elements and uniform distribution of constituent elements was confirmed by EDAX mapping. Thermal variation of magnetic susceptibility from 50 K to 950 K was analyzed to know the presence of different magnetic phases in composites. Analyses of zero field cooled and field cooled magnetization variation, observed as a function of temperature and magnetization vs field loops, recorded by VSM reveal the presence of antiferromagnetism in both composites with a maximum magnetization of 0.85 emu/g for (YAFO)0.3(BNBT)0.7 and 1.12 emu/g for (YAFO)0.5(BNBT)0.5 at room temperature (300 K). Dielectric properties observed as a function of temperature (300–450 K) and frequency (100 Hz to 5 MHz) provided various important information like permittivity, loss factor, ferroelectric to paraelectric transition temperature, etc. Room temperature dielectric strength of ∼240 with a very low loss of ∼5, indicates good dielectric nature of both composites. Direct observation of the ferroelectric loop indicates the presence of better ferroelectricity in (YAFO)0.3(BNBT)0.7 (Pmax – ∼0.029 µc/cm2) compared to (YAFO)0.5(BNBT)0.5 (Pmax – ∼0.018 µc/cm2). Magnetocapacitance coefficient is also higher in (YAFO)0.3(BNBT)0.7(∼6%) compared to (YAFO)0.5(BNBT)0.5(∼4%). All these investigations suggest that (YAFO)0.3(BNBT)0.7 can be considered a potential candidate as type II magnetoelectric multiferroic.

Optothermal and temperature reliant phonon dynamics probed by Raman spectroscopy

The work compares the dependency of temperature on the out of plane and in-plane Raman modes of DVT grown crystalline WSe2 with that of Co and Ni incorporated samples. The structural validations were recognized from their X-Ray diffractograms. The alteration in the mode positions reliant on temperature led to the deduction of first-order temperature coefficients in the range of 10−3 cm−1/K. The observed shift originates from the three-phonon anharmonic process. The optothermal method, where the laser holds the role of a heat source in instigating a shift in the modes has also been documented, thermal conductivity of the materials has been deduced from the same.

Sedimentary facies and textural characteristics of Cretaceous sandstones in the southern Bida Basin, Nigeria: Implication for reservoir potential and depositional environment

A study of sedimentary facies, mineral and textural characteristics of sections of conglomerates/pebbles and sandstone facies found within the Lokoja and Patti Formations in southern Bida Basin, Nigeria, is carried out to evaluate the paleo-environment and reservoir quality of the sandstones of the formations through field observations and textural and mineralogical (using X-Ray Diffractogram) analyses. Nine lithofacies are identified and grouped into three main facies associations. These sedimentary facies suggest deposition in both foreshore and estuaries. The mineral analysis (XRD) shows that the quartz content in sandstone facies of the Lokoja Formation ranges between 49% and 67%, and that of the Patti Sandstone between 43% and 56%, indicating a quartz dominance. The granulometric studies reveal that the Lokoja Formation comprises coarse-to medium-grained (−0.63 to 1.30 φ) sandstone with moderate-poor sorting of 0.72–1.82 φ. On the other hand, medium to fine-grained sandstones dominate the Patti Formation, which is averagely poorly sorted (1.29–1.54 φ). The sandstones are coarsely skewed to finely skewed, with the kurtosis ranging from very platykurtic to leptokurtic. Morphological results of the pebbles from both Lokoja and Patti Formations indicate that the study areas are mainly characterized by the interplay of both wave and fluvial processes, which suggests that the environment of deposition of sandstone facies is predominantly of the fluvial to the shallow marine environment with the indication of tidal influence.Integrating sedimentary facies and textural results suggests subtidal sand ridge/foreshore, estuarine mudflat, and estuarine delta environments with fluvial influences. Evidence from the textural and mineral characteristics indicate that the sandstone facies of the Lokoja and Patti Formations are fairly matured and can act as potential hydrocarbon reservoirs in the formations. The facies, XRD mineral, and textural results have revealed potential hydrocarbon reservoir areas and paleo-depositional features of the Lokoja and Patti Formations.

Synthesis and structural characterization of nanocrystalline silicon by high energy mechanical milling using Al2O3 media

High energy mechanical milling was used to fabricate nanoparticulate Si using Al2O3 grinding media. Two ratios of grinding media to charge of 5 and 10 were used with milling times, such as 7, 10, 13, 16, and 19 h. Morphology of the milled powders was investigated by scanning and transmission electron microscopy. Crystallinity of the milled powders was found to be preserved for all milling conditions without amorphization. Crystallite size of the milled powders was calculated from x-ray diffractograms by various methods. From morphology and crystallite size it was observed that 13 h of milling is the optimum time to produce well dispersed Si nanoparticulates. Further increase in milling duration clearly indicated agglomeration of the powders and cold welding of the crystallites for samples of both media-to-charge ratios. X-ray diffractograms and Raman spectrographs of the milled samples were used to calculate the strain induced in the materials, which indicated progressive increase in strain with milling duration. The results indicate that Al2O3 milling media can be used with optimized process conditions for the production of large quantities of nanoparticulate Si.

Multiferroic properties and magnetoelectric coupling observed in nanocrystalline HoFeO3

Nanocrystalline holmium orthoferrite (HoFeO3) was synthesized by the chemical sol-gel technique. The main focus of attention was to explore the behavior of nanocrystalline system of HoFeO3 in the context of multiferroicity. Structural investigation by observing X-ray diffractograms and its thorough Rietveld analysis was carried out in detail which confirms the deviation in crystallographic structure. Structural study confirms the pure orthorhombic (Pnma) phase of HoFeO3 with zero impurity including the presence of uniform particle size distribution in the nano regime. Different useful structural parameters were also calculated from this theoretically generated pattern, which help to understand the magnetoelectric behavior explored in the sample. Surface morphology studied by FESEM micrographs confirmed a more or less uniform grain distribution in nano regime. EDAX spectra and mapping confirms the elemental purity. Thermal variation of magnetization measurements of HoFeO3 was carried out under zero-field cooled and field (~200 Oe) cooled conditions. Also, variation of magnetization with field (MH Loop) yields the presence of magnetic ordering with a relatively high value of magnetization compared to its corresponding bulk counterpart. During field-variation, magnetization value wasn’t yet saturated even at the maximum applied field of ~3 T, indicating the presence of magnetic ordering and superparamagnetism. Detailed high-temperature dielectric study including thermal variation, as well as frequency variation of dielectric constant together with related electric parameters provide various important information like ferro to para transition temperature, etc. These observations and various analyzes including Cole-Cole analysis of frequency variation of permittivity, Nyquist plot impedance analysis, etc. provide all dielectric parameters which are essential to understand the dielectric properties of the sample. The studies of ferroelectric loop and presence of room temperature magnetoelectric coupling suggest type-II multiferroicity of the present system of HoFeO3, which is usually not found in the bulk system. Presence of prominent remnant polarization with feeble dielectric loss and substantial magnetization clearly establishes the multiferroic candidature of nanocrystalline HoFeO3. This signature of multiferroicity will definitely strengthen the quality of application of the sample in M-E devices.

Nanosized sulfated zirconia with brnsted acid sites prepared without the use of solvents using zircon-based ZR (OH)4 mediated zirconia 1-D nanomaterials

Zirconia 1-D nanomaterials have shown extraordinary and unique capabilities ranging from electronics and medical technologies to chemical engineering and biotechnology. Polyethylene glycol 6000 (PEG6000) was used as a structure-directing template to guide the synthesis of zirconia 1-D nanomaterials from zirconium hydrates manufactured locallyof the nanomaterials. There was a wide range of PEG/Zr mole ratios (0.067 to 0.167), pH was set at 9, the temperature was set at 80°C, and the ageing periods were anywhere from one to three hours. For the mineralogy of the synthetic zirconia, an X-ray diffractogram was employed, and the thermal behaviour of the zirconia was evaluated using a thermal gradient differential thermal analysis technique (TG-DTA). Meanwhile, scanning and transmission electron microscopes were used to study the zirconia that had been manufactured.