Differential Thermal Analysis Data Research Articles

The quasi-binary phase diagrams of R 2Fe14B–Ce2Fe14B (R = Nd, Pr) systems

Abstract The phase relations of the R 2Fe14B–Ce2Fe14B (R = Nd, Pr) pseudobinary systems have been investigated by using X-ray powder diffraction, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and differential thermal analysis. The X-ray powder diffraction results show that continuous solid solutions were formed in this R 2Fe14B–Ce2Fe14B (R = Nd, Pr) pseudobinary systems, and all (R , Ce)2Fe14B solid solutions belong to the tetragonal structure with space group P42/mnm. With the increase in Ce content, the lattice parameters a, c, the peritectic reaction temperatures of the (R, Ce)2Fe14B (R = Nd, Pr) solid solutions decrease linearly, and the cell volume V varies in the form of the regression line. Based on the X-ray powder diffraction results and differential thermal analysis data, the quasi-binary phase diagrams of the R 2Fe14B–Ce2Fe14B (R = Nd, Pr) systems have been established.

Comprehensive study of optical, thermal, and gamma-ray shielding properties of B2O3–SiO2–BeO– MgO–La2O3, glasses

The purpose of this work is to study the thermal, optical, structural, and radiation-shielding features of glass system with composition 57B2O3–16SiO2–11BeO- (16-x) MgO-xLa2O3, x = (0≤x≥16). The structural characteristics of glass samples are examined using XRD. This glass's molar volume decreased from 18.21 to 17.46 (cm³/mol), while its density increased from 3.213 to 5.967 g/cm³. Differential thermal analysis data were used to assess the thermal stability (ΔT) for BSLa samples. It was discovered that when the La2O3 amount increased, the glass stability increased. The optical band gap (Eoptdi), (Eoptindi) and Urbach's energy (Eu) were computed using UV absorption spectra. (Eoptdi) decrease from 4.323 to 3.816 eV and (Eoptindi) decrease from 3.413 to 2.95 eV, whereas (Eu) increase from 0.278 to 0.324 as a result of the changes of borosilicate's structured caused by the addition of La2O3. The examined glasses may be utilized for non-linear optical applications, according to the high (n) and low metallization (M) values. The Phy-X tool was utilized to obtain (MAC), (LAC), and (Zeff) of the suggested glasses within the energies 0.015–15 MeV. The BSLa16 sample achieved the highest values of the (MAC), (LAC), and (Zeff). Consequently, BSLa16 is a good option for gamma-ray shielding applications.

The role of MgO on physical and bioactive properties of borophosphate glasses for biomedical applications

In this work, a novel series of borophosphate glasses of the system 40B2O3–25P2O5–(20-x)Na2O–15CaF2–xMgO (x = 0, 2.5, 5, 7.5, and 10 mol%) were synthesized using the melt-quenching technique. The effect of replacing Na2O with MgO in the glasses was analyzed by the physical and bioactive properties. The glasses were characterized by density, molar volume, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Differential thermal analysis (DTA), bioactivity tests in simulated body fluid (SBF), pH measurements, mass loss, and verification of cellular compatibility in RAW 247 murine macrophages. XRD and FTIR analyses were performed before and after immersion in SBF to verify the bioactivity. Density, molar volume and FTIR results before SBF showed structural changes in the glasses due to the addition of MgO. The pH and mass loss measurements allowed to verify the degradation behavior of the glass series as a function of MgO concentration. The DTA data showed an increase in Tg, Tx, and thermal stability due to the increase in MgO addition. XRD and FTIR analyses after SBF soaking showed superficial formation of apatites and other calcium phosphates of biological interest in the samples, attesting the bioactivity. Cytotoxicity assessed by MTT assay on the cell line RAW 247 showed that at a concentration of 500 μg/mL all glasses were compatible (non-cytotoxic). The results suggest that the synthesized glasses are bioactive, with the sample containing 5 mol% MgO exhibiting the bioactivity and biocompatibility required for biomaterial applications.

Crystallization kinetics analysis of Ge18BixSe82-x chalcogenide glasses alloys by using non-isothermal methods

The melt quench method is used to prepare the chalcogenide glass Ge18BixSe82-x (x: 0.5, 2, 4, 6, and 8 at percent). The samples are characterized using X-ray diffraction (XRD) and a scan electron microscope (SEM). The kinetics of crystallization of the chalcogenide glasses under consideration are investigated by using Differential Thermal Analysis (DTA) under non-isothermal conditions. Different models are used to calculate the activation energy of crystallization (Ec). The Kissenger-Akahira-Sunose (KAS) method is used to calculate the change of activation energy with crystallization volume fraction (Ecα). As well, the activation energy of glass transitions is measured by using different models. The results of fitting the experimental DTA data to the computed DTA curves show that the Johnson-Mehl-Avrami (JMA) model cannot represent the crystallization process of Ge18BixSe82-x glass. Our findings show that the Sestak-Berggren (SB) model is better suited to describe the crystallization process for the glass under investigation.

A lyophilized surfactant-based rutin formulation with improved physical characteristics and dissolution for oral delivery

Rutin (RUT) is a phytochemical flavonoid with numerous therapeutic potentials including antihypertension, cardioprotective, neuroprotective, and anti-cancer activities. Its clinical use is inhibited due to its poor aqueous solubility and permeability over oral administration. The present study aimed to overcome these problems through micellization and entrapment of RUT in solid dispersion (SD) using Poloxamer (POL) 407 and 188 as surfactant-based matrices. The RUT/SD formulations were prepared in serial drug loading concentrations in weight percentage to the total solid. The physical properties of the formed RUT/SD solids were characterized by several methods including polarizing microscopy, differential thermal analysis (DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and dissolution study. The dissolution test was performed using a paddle dissolution apparatus and samples were analyzed using UV spectrophotometry. Polarized microscope confirmed that the optical behaviors of the RUT/SD implied a formation of miscible RUT with POL matrices. The morphology of RUT/SDs varied from porous matrices with craters to smoother surfaces as a function of RUT concentrations. XRD and DTA data exhibited that RUT existed as partially amorphous. These data indicated that the higher concentration of RUT in the RUT/SD formulations, the higher amorphous proportion of the RUT in the solid state. Henceforth, this led to an increase in the percentage of dissolved RUT from the developed RUT/SD formulations at 94 to 100% compared to pure RUT at only < 35% within an hour. The present study disclosed the successful improvements in the physical characteristics of the RUT/SD formulations and their potencies for the future development for oral formulation.

PHASE FORMATION DURING ALUMINOTHERMAL REDUCTION OF Ti, Nb, Gd (Y) FROM OXIDES

Alloys based on titanium and aluminum with additions of niobium and rare-earth metals have unique mechanical and heat-resistant properties, and also it likely that such alloys would have increased corrosion resistance. The method of thermodynamic modeling using the HSC program was used to study a system with aluminum consumption varying in the range from 0 to 100% of the mass of the initial charge. The features of phase formation in Al–[50TiO2–5Nb2O5–1Y2O3 (Gd2O3)] systems have been studied. The calculation of the heat balance of the process at 1600°C and 44% of Al was – 0.196 MJ per 1 kg of charge, which indicates the possibility of its occurrence with only the aluminothermic reactions. The reduction of titanium and niobium can proceed by reactions through the formation of their oxides of lower valency – TiO, NbO2, NbO. The aluminothermic reduction of gadolinium is thermodynamically possible only at temperatures below 1200°C. The reduction of yttrium through the interaction of Y2O3 with aluminum with the formation of AlY, Al2Y3 AlY2 compounds for the range of 1000–1800°C is thermodynamically impossible. The results of thermodynamic modeling of interactions correlated well with the data of differential thermal and X-ray phase analysis using STA 449 F3 Jupiter (NETZSCH) synchronous thermal analysis and XRD-7000 diffractometer (Shimadzu) with automatic program control, respectively. It was found that the process enters the active phase after the appearance of liquid aluminum and, apparently, is accompanied by exothermic effects with the formation of double and triple intermetallic compounds of aluminum with rare (Nb, Ti) and rare earth (Gd, Y) metals. Transformation of titanium dioxide and niobium pentoxide in the process of transformations is likely carried out through successive and parallel stages of formation of simple and complex oxides with low oxidation states. At the initial stages of the interaction of aluminum with oxides, niobium and titanium aluminides are mainly formed. At subsequent stages, the formation of more complex compounds is observed. At temperatures above 1300°C, ternary intermetallic compounds Al43Nb4Gd6, Ti4Al20Gd and Ti4Al3Y6, Al3Ti, Al0.23Nb0.07Ti0.7 are formed. Gadolinium and yttrium tend to form complex intermetallic compounds in such systems.

Celtis tournefortii LAM. Yaprak Özütüyle Gümüş Nanopartiküllerin Hızlı Biyosentezi; Antimikrobiyal ve Antikanser Aktivitelerinin İncelenmesi

The usage of metallic nanoparticles are very common. Environmentally friendly approaches in obtaining nanoparticles attract a lot of attention because of their advantages. In this study, an easy and economical biosynthesis of silver nanoparticles (AgNPs) was made with the extract of Celtis tournefortii LAM. leaf. For the characterization of synthesized nanoparticles, Spectrophotometer (UV-vis), Transmission Electron Microscope (TEM), Field Emission Scan Electron Microscopy (FE-SEM), Atomic Power Microscopy (AFM), Electron Disperse X-ray (EDX) Fourier Transformation Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Thermogravimetric and Differential Thermal Analysis (TGA-DTA), Zeta Sizer and Zeta Potential Analysis data were used. As a result of the data analysis, it was determined that the AgNPs had a spherical appearance, an average size distribution of 4.8 nm, had a maximum absorbance at a wavelength of 482.13 nm, a crystal nanosize of 10.95 nm, and a surface charge of -21.6 mV. Inhibition activities of AgNPs on the growth of pathogenic strains were determined by the microdilution method. The results showed that the nanoparticles were effective even at low concentrations. The Minimum Inhibitory Concentration (MIC) value of the tested materials on the growth of the strains was found between 0.03-1.00 µg mL-1. Anticancer activity of AgNPs was investigated on CaCo-2, U118, Skov3 cancer cell lines and healthy cell line HDF by the MTT method.

SELENOLANES, SELENATRANS AND ESTERS OF SELENIC ACID

It is known that selenic acid and selenium dioxide act as oxidizing agents in reactions with α-oxides when heated. The proposed paper presents data on the synthesis of organoselenium compounds based on reactions of α-oxides with selenic acid and its anhydride, where the latter act as selenation agents. It was found that in the presence of catalytic amounts of boron trifluoride esterate in the reactions of oxiranes with acid the oxirane ring opens both according to the rule and against the Krasussky rule with the formation of a mixture of α- and β- isomers of selenic acid esters. In contrast to the acid, the reactions of oxiranes with selendioxide involve the expansion of the oxirane ring to form functionally substituted selenolanes. This paper is followed by the analysis of the literature material on atranes, a unique class of heterocyclic compounds with distinct biologically active properties, and their element derivatives (B, Ge, Si, etc.). For the first time we have synthesized selenatranol, which is not described in the literature. In future it may not only possess bioactive properties in itself, like the majority of organoselenium compounds, but also be a drug precursor. Acetylselenatranol was synthesized by the reaction of selenatranol with acetic anhydride in acid medium. The data of IR, PMR spectra and elemental analysis of the synthesized compounds as well as the data of thermogravimetric (TGA) and differential thermal analysis (DTA) of some of them are given

The formation of phase transitions in CuNiS under the influence of gamma irradiation

The concentrations of forming defects during phase transitions (PTs) and elastic coefficients in the [Formula: see text][Formula: see text]S compound were determined based on differential thermal analysis (DTA) data [Formula: see text]. The sample was studied under the influence of [Formula: see text] irradiation (at a dose of 25 Mrad) and it was shown that the [Formula: see text] curves coincide each other before and after irradiation. It was established that [Formula: see text], [Formula: see text], [Formula: see text] modifications are commensurate when heating the sample. A certain number of defects in S atoms at lattice sites and defects in Cu atoms (also Ni atoms) in interstitial sites of the sublattice are some of the causes of lattice rearrangement.

Effect of hafnium addition on microstructure and room temperature mechanical properties of the Ti-48Al-2Cr-2Nb intermetallic alloy

Microstructures, phase transformations and mechanical properties of the Ti-48Al-2Cr-2Nb-xHf (4822-xHf, x = 0, 2, 4, 6 at%) intermetallic alloys were investigated. The alloys were fabricated by vacuum arc remelting followed by hot isostatic pressing and homogenization treatment. The results showed that Hf alloying leads to a significant microstructure refinement in terms of both colony size and inter-lamellar spacing. Homogenization at 1400 °C resulted in a fully lamellar (FL) microstructure in 4822 and 2Hf alloys, while nearly lamellar (NL) in 4Hf and 6Hf alloys. Differential thermal analysis (DTA) demonstrated that Hf addition up to 2 at% has a slight contribution to phase transition sequences, but a significant implication to the phase equilibrium of the alloys with further Hf content. Based on the DTA data and annealing at 1450 °C, the solvus temperature of the eutectic phases was estimated to be over the range of 1430–1440 °C. Although the eutectic phases of Al3Hf2 and TiAl2 formed during solidification of the high-Hf alloys did not undergo any phase transition, both size and volume fraction of the eutectic cells increased due to the solvus of these metastable eutectic phases. The orientation relationship {111}Tetragonal//{001}Orthorhombic detected between the eutectic phases and their surrounding matrix confirmed the occurrence of γc (TiAl) → eutectics (Al3Hf2, TiAl2) phase transformation. Small punch tests results showed that the 2Hf and 4Hf alloys exhibit a higher maximum load (Fm) than the base 4822 alloy due to the solid solution effect of Hf and finer inter-lamellar spacing. Nevertheless, the brittle behavior of the eutectic phases dramatically deteriorated mechanical performance such that the 6Hf alloy possessed the lowest Fm and displacement. The major fracture mode changed from trans-lamellar to inter-lamellar as the Hf content increased from 4 to 6 at%.

Preparation and characterization of Trivalent lanthanide ion complexes with tridentate mono azo Ligand

The lanthanide complexes of 4-(2-pyridylazo)-resorcinol are prepared in solid state. All compounds have been characterized by means of elemental analysis (C.H.N) molar conductance, magnetic susceptibility and analytical spectral studies IR and UV-Visible spectral techniques. While the complexes have additionally been characterized by differential thermal analysis data and are formulated as [Ln(C11H8N3O2)3].H2O Ln = Pr3+ , Nd3+ and Sm3+ ; [Ln(C11H8N3O2)3] Ln = Eu3+, Er3+ and Yb3+ . The results of these studies on the synthesis and structural characterization, suggest neutral lanthanide complexes in which the mono azo ligand being a uninegative (deprotonated form) and tridentate ligand. The absorption spectral profiles suggest a coordination number of nine around Ln(III) ions in the complexes.

Co-extraction of valuable metals and kinetics analysis in chlorination process of low-grade nickel-copper sulfide ore

To efficiently co-extract Ni and Cu from low-grade nickel-copper sulfide ore, chlorination roasting with NH4Cl followed by a water leaching process was investigated. The results show that 98.4% Ni and 98.5% Cu can be synchronously extracted when the ore particle size is 75-80 μm, the roasting time is 2 h, the mass ratio of NH4Cl to ore is 1.6:1 and the roasting temperature is 550 °C. The evolution behavior of various minerals was elucidated using X-ray diffraction (XRD) coupled with scanning electron microscopy (SEM). The kinetics of the chlorination process based on the differential thermal and thermogravimetric analysis (DTA-TG) data was analyzed by Kissinger method and Flynn-Wall-Ozawa (FWO) method. The chlorination process of low-grade nickel-copper sulfide ore mainly contains two stages: the decomposition of NH4Cl and the chlorination of ore. The maximum apparent activation energies (Ea) at two stages are determined to be 114.8 and 144.6 kJ/mol, respectively. The condensed product of exhaust gas is determined to be ammonium chloride, which can be recycled as the reactant again, making the process economic and clean.

Cross-Linked Hydrogels Based on PolyNIPAAm and Acid-Activated Laponite RD: Swelling and Tunable Thermosensitivity.

The effects of acid activation of Laponite RD (Lap) on the structure and properties of activated Lap nanoparticles (aLap) and the properties of polyNIPAAm hydrogels physically cross-linked by aLap have been studied. The acid activation of Lap by the sulfuric acid was done using the concentration of sulfuric acid within the interval Ca = 0.525-14.58% for 10 h. For slightly activated samples (Ca ≤ 1.25 wt %), the significant increase of the specific surface area (by ≈1.56 times) was accompanied with a significant decrease in both the values of the specific heat of immersion in water and n-decane. However, the hydrophilic properties of all samples S0-S5 were still observed. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) data, Fourier transform infrared (FTIR) spectra, and X-ray diffraction (XRD) patterns demonstrated that the acid activation resulted in the destruction of the crystal lattice of Lap, leaching of magnesium and lithium, and formation of the amorphous phases. Moreover, the acid activation significantly affected aggregation and negative surface charges of the aLap faces in aqueous suspension. The effects of aLap on the swelling properties and cooperativity in the phase transitions of polyNIPAAm hydrogels cross-linked by aLap are also discussed. It was demonstrated that an increase in Ca resulted in a significant increase in the equilibrium degree of swelling of the hydrogels and a decrease in the hydrogel phase-transition temperature from the swollen phase to the shrunken phase.

Optimization of Heat Treatment and Cu Ions Additions to Enhance Optical and Photoluminescence Properties of Transparent Mica Glass Ceramic

A set of mica glasses containing copper ions were synthesized using melt quenching technique with the chemical composition Na(1 − X)CuxMg3AlSi3O10F2, where X = 0, 0.05, 0.07, and 0.1. The samples were crystallized at temperatures obtained by differential thermal analysis (DTA) data. X-ray analysis confirmed the crystallization of mica (NaAl3Si3O11), MgF2 and pyrope (Mg3Al2Si3O12). Transparent glass ceramic with nano-sized crystal < 15 nm was obtained after heat treatment at 550°C/4 h+650°C/0.5 h. The characteristic peaks of Fourier transform infrared spectroscopy (FTIR) for glass and glass ceramic were due to the SiO4 group. The optical properties were investigated using ultraviolet-visible (UV-Vis) absorption spectra. The optical band gap energies for glasses were also calculated, revealing Eopt =1.9 for X = 0 and increased to 3.45 eV for X = 0.1, i.e., located in the semiconductor range. The photoluminescence (PL) properties and CIE chromaticity diagrams of the as-prepared mica glasses and transparent glass ceramic revealed variation in color from pale purple to blue and light blue. These results indicate that the prepared mica materials can be used in different applications.

Formulation Design and Cell Cytotoxicity of Curcumin-Loaded Liposomal Solid Gels for Anti-Hepatitis C Virus.

Backgrounds Curcumin (CUR) is a low-molecular-weight polyphenolic substance obtained from the tuber part of Curcuma species. Anti-inflammatory and anti-hepatitis C virus (HCV) activities have been associated with CUR. However, its poor aqueous solubility and low systemic bioavailability have been the challenges in improving the therapeutic efficacy of curcumin. Aim The study aimed to produce CUR-loaded liposomal solid gels as anti-HCV delivery systems. Parameters including the physical characteristics and the cell cytotoxicity properties were evaluated. Methods The freeze-drying technique was applied to manufacture the CUR-loaded liposomal solid gels. Scanning electron microscopy (SEM), X-ray diffractometry (XRD), and differential thermal analysis (DTA) were involved to reveal the characteristics of the solid gels. Such characteristics were as follows: the morphology and the microscopic structure of the solid gels, the crystallinity structure of the curcumin, and the thermal properties of the mixtures. Furthermore, their cell cytotoxicity was investigated using a Huh7it cell line. Results The SEM images confirmed that curcumin liposomes were intact and trapped in the solid gel matrix. The XRD data showed flat patterns diffractograms of the formulations, confirming the transformation of CUR from crystalline to amorphous form. The DTA thermograms showed a single melting endothermic peak at a higher temperature around 200°C, indicating a single-phase transition of the mixtures. The XRD and DTA data revealed the molecular dispersion of CUR in the developed formulations. The cytotoxicity data provided as cell cytotoxicity 50 (CC50) for all formulations were ≥25 mg. These data confirmed that the developed liposomal solid gels were not cytotoxic to Huh7it cell line, indicating that the anti-HCV activity would be through a specific pathway and not by its toxicity. Conclusion The CUR-loaded liposomal solid gels exhibited the potential and offered an alternative dosage form to improve the therapeutic efficacy of curcumin as an anti-HCV.

THE DIFFERENTIAL THERMAL ANALYSIS OF COMPLEX CATALYTIC SYSTEM OF 50%Cu3(PO4)2•50%Ni3(PO4)2

The catalytic system of 50% Cu3(PO4)2∙50% Ni3(PO4)2 based on Copper (II) and Nickel (II) orthophosphates was synthesized by the coprecipitation method according to the method developed at the Department of Physical and Colloid Chemistry of Uzhhorod National University. The synthesized system was investigated by the method of differential thermal analysis. The obtained results can be interpreted in favor of the formation of a new phase, which is formed due to the equiatomic interaction of the initial components. Thus, a number of thermal effects different from Cu3(PO4)2∙3H2O and Ni3(PO4)2∙8H2O are observed on the corresponding thermogram. The only endothermic effect at 117 ° C is not recorded on the thermograms of the starting components. In the case of a solid solution or a simple mixture of phases based on starting phosphates, this effect should be observed at intermediate temperatures in the range from 129°C to 268°C. Probably, the newly formed phase, by the number of moles of water of crystallization, differs from the original individual orthophosphates. Information about a more accurate number of molecules of chemically bound water in hydrated forms of the synthesized complex copper-nickel phosphate catalyst will allow to establish the results of additional studies by derivatographic or gravimetric analyzes, which were not performed in this work. After dehydration with a further increase in temperature, no endothermic effect for a complex catalytic system is observed. Instead, four exothermic effects are recorded at once: the first two - at 456ºС and 564ºС (both insignificant in area), and the next two at slightly higher temperatures - 658ºС and 777ºС (larger in area). The effects at 564ºC and 658ºC can be attributed to the crystallization of dehydrated Cu3(PO4)2. The exoeffect at 777°C corresponds to the formation of the structure of dehydrated orthophosphate Nickel Ni3(PO4)2. Thus, the obtained experimental data of differential thermal analysis confirm the effective modifying role of Ni2+ ions on the structure, phase formation and a number of physicochemical properties of copper (II) phosphate in the synthesis of a complex oxide catalyst. This made it possible to obtain a new cheap and active complex acid catalyst with improved catalytic properties of 50 % Cu3(PO4)2∙50 % Ni3(PO4)2, which can be used for the process of converting natural gas components into valuable products of the chemical industry.&#x0D; Keywords: differential thermal analysis (DTA); catalysts; сopper (II) orthophosphate; nickel (II) orthophosphate; catalytic 50 % Cu3(PO4)2∙50 % Ni3(PO4)2 system.

Entropy analysis and grey correlation coefficient cluster analysis of multiple indexes of 5 kinds of condiments

Five condiments, including cinnamon, tangerine peel, clove, licorice, amomum, were selected as the research objects in Guangxi, China. The combustion heat, differential thermal gravimetric analysis, fat, crude fiber, trace element, calcium and ash content data for 5 condiments were determined. According to the combustion heat, differential thermal gravimetric analysis, fat, crude fiber, trace element, calcium and ash content data of condiments, we constructed a systematic multi-index comprehensive evaluation system using entropy analysis, gray pattern recognition and grey correlation coefficient cluster analysis. The multi-index comprehensive evaluation system established by the research provides a new idea for the nutritional evaluation of condiments. This research provides a strong scientific basis for the large-scale development of condiment resources and condiment classification research, basic support for the selection of condiment raw materials.

Samarium doped calcium silicate derived from agro-food wastes and their structural, optical and luminescent properties

Samarium doped calcium silicates (Ca2−xSiO4:xSm3+, (x(%) = 0.25, 0.50, 0.75, 1.00) are synthesized using cost effective natural resources such as rice husk ash and egg shell powder through solid-state reaction method. The structural, optical, and photoluminescent properties of the as-prepared samples are reported. X-ray diffraction and Rietveld refinement results confirm that monoclinic- Ca2SiO4 phase is stabilized at room temperature in agro-food waste derived phosphors. Differential thermal analysis data provides information about the phase transformations. Scanning electron microscope images show that the synthesized samples have spherical morphology. Ca2SiO4 related vibrational bands appear in the Fourier transform infrared spectrum. Optical band gap of these phosphors is found to lie in the range 3.56–3.67 eV. Agro-food wastes inherently contain titanium in trace amounts thus, the photoluminescence emission spectrum consists of bands linked to both samarium and titanium ions. Presence of titanium makes these phosphors inherently luminescent. CIE co-ordinates of these phosphors lie in the bluish-green region. These results suggest that agro-food wastes have excellent potential of being used as precursors for synthesizing visible light emitting phosphors. Moreover, present study paves the way for effectively utilizing agro-food wastes for synthesizing environment friendly and cost-effective phosphors.

Studies on processing of layered oxide‐bonded porous sic ceramic filter materials

AbstractOxide‐bonded porous SiC ceramic filter supports were prepared using SiC powder (d50 = 212 µm), Al2O3, and clay as bond forming additives and graphite as pore former following reaction bonding of powder compacts at 1400°C in air. Reaction bonding characteristics, phase composition, porosity, pore size, mechanical strength, and microstructure of porous SiC ceramic supports were investigated. Mullite bond phase formation kinetics was studied following the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model using non‐isothermal differential thermal analysis (DTA) data. Compared to porous SiC ceramic filter supports having no needle‐like mullite bond phase, materials processed by the mullite bonding technique exhibited higher average strength (22.1%) and elastic modulus (5.4%) at a similar porosity level of ~38%, with upper and lower bounds of their strength, modulus, and porosity being 39.1 MPa, 40.2 GPa, and 36.3% and 34.2 MPa, 31.3 GPa, and 33.0%, respectively. Spray coating method was applied for preparation of oxidation‐bonded SiC filtration layer having thickness of ~150 µm and pore size of ~5–20 µm over the porous SiC support compacts using aqueous slurry made of fine SiC powder (d50 = 15 µm) followed by sintering. The layered ceramics thus prepared are potential materials for gas filter applications.

Curcumin micelles entrapped in eudragit S-100 matrix: a synergistic strategy for enhanced oral delivery.

Background:Therapeutic activities of curcumin (CUR) via oral administration are hampered by the lack of bioavailability due to its poor water solubility and rapid degradation in GI tract.Materials & methods:This preliminary study developed CUR micelle-eudragit S100 (EUD) dry powder (CM-EDP) spray-dried formulations. Poloxamer 407 was used as a micelle-forming agent and EUD as an entrapping matrix for protection over hydrolysis and enzymes in the GI tract.Results:The morphology of CM-EDP showed agglomeration with cratering on the surface of particles. Differential thermal analysis and x-ray diffractometry data exhibited evidence that CUR was converted into amorphous solid. An increased concentration of micelle-forming and dispersion matrix polymers resulted in a high fraction of drug being converted into the amorphous state. A significant increase in dissolution by 7–10 times was achieved compared with that of raw CUR.Conclusion:The present study disclosed the CM-EDP potency for future development of CUR oral formulation.