scholarly journals Characterization of superparamagnetic MgxZn1−x Fe2O4 powders

2007 ◽  
Vol 5 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Violeta Kassabova-Zhetcheva ◽  
Lilyana Pavlova ◽  
Bisserka Samuneva ◽  
Zara Cherkezova-Zheleva ◽  
Ivan Mitov ◽  
...  
Keyword(s):  
Spinel Phase ◽  
Elementary Cell ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Small Particles ◽  
Magnetic Studies ◽  
Superparamagnetic Relaxation ◽  
Diffraction Patterns ◽  
Quadruple Splitting

AbstractStructural and magnetic properties of Mgx Zn1−x Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mgx Zn1−x Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.

scholarly journals Development and Characterization of Norite-Based Cementitious Binder from an Ilmenite Mine Waste Stream

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Mahmoud Khalifeh ◽  
Arild Saasen ◽  
Helge B. Larsen ◽  
Helge Hodne
Keyword(s):  
Mine Waste ◽  
Major Type ◽  
Strength Development ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Cementitious Binder ◽  
Degree Of Crystallization ◽  
Diffraction Patterns ◽  
Alkali Activated

Norite is a major type of solid waste generated during the production of ilmenite. This study focuses on the usability of norite as a solid precursor of alkali-activated cement. Sensitivity analysis was performed to find the influence of different alkali types and particle sizes of the source material on polycondensation. Norite was ground and mixed with sodium hydroxide and potassium hydroxide solutions to produce a binder. Potassium-containing systems were more effective compared to sodium-containing systems with respect to strength development. The X-ray diffraction patterns indicated formation of zeolites, albite, and oligoclase based on the type of activator and used additives. The patterns also revealed formation of an amorphous phase in the matrices of the binder that was cured at 87°C. Microstructure analysis revealed some degree of crystallization with different Si : Al ratios, which indicated heterogeneity of the binder matrices.

scholarly journals Perbaikan Kelarutan Albendazol Melalui Pembentukan Kristal Multikomponen dengan Asam Malat

2020 ◽  
Vol 6 (1) ◽  
pp. 114-123
Author(s):  
Fikri Alatas ◽  
Fahmi Abdul Azizsidiq ◽  
Titta Hartyana Sutarna ◽  
Hestyari Ratih ◽  
Sundani Nurono Soewandhi
Keyword(s):  
Phase Solubility ◽  
Crystal Formation ◽  
Solubility Curve ◽  
X Ray Diffraction ◽  
Ethanol Mixture ◽  
X Ray ◽  
Grinding Method ◽  
Diffraction Patterns ◽  
Phase Solubility Curve

An effort to improve the solubility of albendazole (ABZ), an anthelmintic drug has been successfully carried out through the formation of multicomponent crystal with dl-malic acid (MAL). Construction of phase solubility curve of ABZ in MAL solution and crystal morphological observations after recrystallization in the acetone-ethanol (9:1) mixture were performed for initial prediction of multicomponent crystal formation. ABZ-MAL multicomponent crystal was prepared by wet grinding or also known as solvent-drop grinding (SDG) with acetone-ethanol (9:1) mixture as a solvent followed by characterization of the multicomponent crystal formation by powder X-ray diffraction and Fourier transform infrared (FTIR) methods. The solubility of ABZ-MAL multicomponent crystal was tested in water at ambient temperature and in pH 1.2, 4.5 and 6.8 of buffered solutions at 37°C. The phase solubility curve of the ABZ in the MAL solution showed type Bs. The ABZ-MAL mixture has a different crystalline morphology than pure ABZ and MAL after recrystallization in the acetone-ethanol mixture (9:1). The powder X-ray diffraction pattern and the FTIR spectrum of ABZ-MAL from SDG different from intact ABZ and MAL powder X-ray diffraction patterns and these results can indicate the ABZ-MAL multicomponent crystal formation. The ABZ-MAL multicomponent crystal has better solubility than pure ABZ in all media used. These results can be concluded that ABZ-MAL multicomponent crystal can be prepared by solvent-drop grinding method with acetone-ethanol (9:1) mixture as a solvent and can increase the solubility of albendazole.

scholarly journals PECHINI SYNTHESIS AND CHARACTERIZATION OF Eu3+ DOPED ZnCo2O4 SPINELS

2005 ◽  
Vol 03 (2) ◽  
pp. 24-29
Author(s):  
P.M. PIMENTEL ◽  
A.M.G. PEDROSA ◽  
H.K.S. SOUZA ◽  
C.N.S. JÚNIOR ◽  
R.C.A. PINTO ◽  
...  
Keyword(s):  
Spinel Structure ◽  
Pechini Method ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spinel Oxides ◽  
Diffraction Patterns ◽  
Pechini Synthesis ◽  
Spinel Structures

Spinel oxides with the composition ZnCo2O4 and ZnCo2O4:Eu3+ have been synthesized by the Pechini method and characterized by X-ray diffraction, infrared spectroscopy, thermal analysis and scanning electron microscopy. IR spectroscopy revealed the presence of n1 and n2 bands, typical of spinel structures. The formation of monophase cubic spinel structure was confirmed by X-ray diffraction patterns. Extra lines corresponding to other phase has been observed in the powders calcined at 900 ºC. The results showed the extremely lower synthesis temperature than those presents in conventional methods.

scholarly journals Preparation and characterization of oleogels with tallow and partially hydrolyzed tallow as organogelators

2021 ◽  
Vol 72 (1) ◽  
pp. e388
Author(s):  
E. Keskin Uslu ◽  
E. Yılmaz
Keyword(s):  
Loss Modulus ◽  
Solid Fat Content ◽  
X Ray Diffraction ◽  
Shear Rates ◽  
Peroxide Values ◽  
Time Sweep ◽  
Diffraction Patterns ◽  
Time Sweep Test ◽  
Addition Level

The aim of this study was to evaluate the organogelation potential of tallow fat (TF) and partially hydrolyzed tallow fat (HTF) against saturated monoglyceride (MG) and a saturated monoglyceride + diglyceride mixture (MDG) as the organogelators. TF itself created oleogel at a 30% addition level, while HTF, MG and MDG oleogels were prepared at 10% addition levels. Fatty acid composition data showed that the oleogel of HTF (HTFO) was quite similar to those of MG and MDG oleogels. Solid fat content, free fatty acidity and peroxide values were found to be in acceptable ranges for HTFO. Thermal properties, crystal morphology and X-ray diffraction patterns were also evaluated. Rheological analyses indicated that all oleogels had higher storage modulus (G´) than loss modulus (G´´). The time-sweep test showed that after applying higher shear rates, the gels re-formed at rest. Further, all oleogels maintained their gelled consistency until around 54 °C. The results suggest that HTF could be a cheap, efficient, fast melting, safe and readily available organogelator.

Growth and Characterization of bulk GaN by Ga Vapor Transport

2004 ◽  
Vol 831 ◽  
Author(s):  
Phanikumar Konkapaka ◽  
Huaqiang Wu ◽  
Yuri Makarov ◽  
Michael G. Spencer
Keyword(s):  
Growth Rates ◽  
Vapor Transport ◽  
Spiral Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Bulk Gan ◽  
Diffraction Patterns

ABSTRACTBulk GaN crystals of dimensions 8.5 mm × 8.5 mm were grown at growth rates greater than 200μm/hr using Gallium Vapor Transport technique. GaN powder and Ammonia were used as the precursors for growing bulk GaN. Nitrogen is used as the carrier gas to transport the Ga vapor that was obtained from the decomposition of GaN powder. During the process, the source GaN powder was kept at 1155°C and the seed at 1180°C. Using this process, it was possible to achieve growth rates of above 200 microns/hr. The GaN layers thus obtained were characterized using X-Ray diffraction [XRD], scanning electron microscopy [SEM], and atomic force microscopy [AFM]. X-ray diffraction patterns showed that the grown GaN layers are single crystals oriented along c direction. AFM studies indicated that the dominant growth mode was dislocation mediated spiral growth. Electrical and Optical characterization were also performed on these samples. Hall mobility measurements indicated a mobility of 550 cm2/V.s and a carrier concentration of 6.67 × 1018/cm3

Preparation by solution mixing and characterization of condensation type poly(dimethyl siloxane)/graphene nanoplatelets composites

2021 ◽  
pp. 002199832110558
Author(s):  
Panayiotis Ketikis ◽  
Efthimios Damopoulos ◽  
Georgios Pilatos ◽  
Panagiotis Klonos ◽  
Apostolos Kyritsis ◽  
...  
Keyword(s):  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Dielectric Relaxation Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Dimethyl Siloxane ◽  
Diffraction Patterns ◽  
The Impact

The impact of the incorporation of graphene nanoplatelets (GN) on the properties of hydroxyl-terminated poly(dimethylsiloxane) (PDMS) matrices was investigated. The composites were prepared by solution mixing, using tetrahydrofuran (THF) as a solvent. Brookfield viscosimetry, implemented during the vulcanization process, revealed that GN increases the viscosity of the system, compared to pristine PDMS, proportionally to its concentration. X-ray diffraction patterns suggested an efficient dispersion of GN in the polysiloxane matrix. The D and G bands ratio (ID/IG) calculation, based on RAMAN spectra of GN/PDMS specimens, revealed more defects in graphene nanoplatelets when incorporated in the PDMS matrix. By differential scanning calorimetry (DSC), a marginal increase in crystallization, glass transition and melting temperatures of PDMS in GN/PDMS composites was observed. Improvement of the thermal stability of LMW PDMS composites, especially for higher GN concentrations (3 and 5 phr), was noticed by thermogravimetric analysis (TGA). Additionally, GN enhanced the tensile strength of composites, up to 73% for the 3 phr GN/LMW PDMS composite. A significant increase in the elongation at break was recorded, whereas no effect on the modulus of elasticity was recorded. The decrease in toluene-swelling, for the LMW PDMS matrix composites, was attributed to the increase in the tortuosity path because of the efficient dispersion of GN. A decrease in oxygen permeability of 55–65% and 44–58% was measured in membranes made of PDMS composites containing 0.5 phr and 1 phr GN, respectively. Dielectric relaxation spectroscopy (DRS) measurements recorded a significant increase in the conductivity of the higher graphene content composites.

The Effect of Ethanol Solvent on Characterization of MAPbI3 Perovskite

2021 ◽  
Vol 1039 ◽  
pp. 307-312
Author(s):  
Mohammad Malik Abood ◽  
Osama Abdul Azeez Dakhil ◽  
Aref Saleh Baron
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Morphological Characteristics ◽  
X Ray Diffraction ◽  
Lead Iodide ◽  
X Ray ◽  
Diffraction Patterns ◽  
Photovoltaic Technologies ◽  
Perovskite Photovoltaic

Methyl ammonium lead iodide CH3NH3PbI3 Perovskite was synthesized by a new method mixing between one and two steps, in addition, the ethanol solvent was used to dissolve CH3NH3I and compared with isopropanol solvent. The characterizations of synthesized perovskite samples included the structural properties, morphological characteristics and optical properties. The intensity and orientation in X-ray diffraction patterns appear clearly in ethanol solvent while disappearing at a peak at 12o due to the speed reaction of perovskite in this solvent. Additionally, the ethanol solvent increasing the grain size of perovskite which homogeneity of the surface morphology. the ethanol solvent cause a decrease in the wavelength of absorbance edge in addition to an increase in the energy bandgap value. Keywords: Ethanol Solvent, Perovskite, Photovoltaic Technologies, X-ray diffraction.

Structural, Optical, Photocatalytic and Electrochemical Studies of PbS Nanoparticles

2020 ◽  
Vol 61 ◽  
pp. 18-31 ◽  
Author(s):  
Peter A. Ajibade ◽  
Abimbola E. Oluwalana
Keyword(s):  
Particle Sizes ◽  
X Ray Diffraction ◽  
Lead Sulphide ◽  
Electron Transfer Process ◽  
Sem Images ◽  
Pbs Nanoparticles ◽  
X Ray ◽  
Diffusion Controlled ◽  
Reversible Redox ◽  
Diffraction Patterns

Oleic acid (OA) and octadecylamine (ODA) capped lead sulphide (PbS) nanoparticles were prepared at 150, 190 and 230 °C. X-ray diffraction patterns indicates that the synthesized PbS nanoparticles were in the rock cubic salt crystalline phase. The particle sizes of the as-prepared PbS nanoparticles are in the range 2.91–10.05 nm for OA-PbS(150), 24.92–39.98 nm for ODA-PbS(150), 9.26 – 29.08 nm for OA-PbS(190), 34.54 – 48.04 nm for ODA-PbS(190), 17.96–88.07 nm for OA-PbS(230) and 53.60 – 94.42 nm for ODA-PbS(230). SEM images revealed flaky and agglomerated spherical like morphology for the nanoparticles. The energy bandgap of the PbS nanoparticles are in the range 4.14 – 4.25 eV, OA-PbS(230) have the lowest bandgap of 4.14 eV while ODA-PbS(150) have the highest bandgap of 4.25 eV. The PbS nanoparticles were used as photocatalyst for the degradation of Rhodamine B and OA-PbS(150) showed efficiency of 44.11% after 360 mins. Cyclic voltammetry of the PbS nanoparticles showed a reversible redox reaction and linear Randles-Sevcik plots indicates electron transfer process is diffusion controlled.

Solids Formation from Synthetic Fuel Reprocessing Solutions: Characterization of Zirconium Molybdate by ICP, XRF, and Raman Microprobe Spectroscopy

1986 ◽  
Vol 40 (3) ◽  
pp. 330-336 ◽  
Author(s):  
B. S. M. Rao ◽  
E. Gantner ◽  
H. G. Müller ◽  
J. Reinhardt ◽  
D. Steinert ◽  
...  
Keyword(s):  
Raman Spectra ◽  
X Ray Diffraction ◽  
Synthetic Fuel ◽  
Precipitation Decrease ◽  
Zirconium Molybdate ◽  
Raman Microprobe ◽  
Hydrated Zirconium ◽  
Diffraction Patterns ◽  
Almost All

Raman microprobe, ICP, and XRF techniques have been applied to characterize the solids precipitated from HNO3 solutions containing Zr and Mo under different solution conditions. The saturation yields of precipitation decrease linearly—in almost all cases—with increasing acid strength, and nearly complete precipitation of Mo occurs in 3-M HNO3 solutions; ionic strength does not seem to affect the yields. Raman spectra of the microparticles indicate that hydrated zirconium molybdate is the main product, except in solutions with large excess of Mo relative to Zr. Identification of the species formed in these solutions is made by comparison of the Raman spectra with the spectra of known compounds. X-ray diffraction patterns of hydrated and thermally treated zirconium molybdate are in accord with the reported crystallographic data.

An X-ray diffraction study of filters used for atmospheric aerosol sampling

1996 ◽  
Vol 11 (3) ◽  
pp. 230-234 ◽  
Author(s):  
M. D. Santos ◽  
J. R. Matos ◽  
L. R. F. Carvalho ◽  
L. M. Sant’Agostino ◽  
M. Korn
Keyword(s):  
Atmospheric Particulate Matter ◽  
Aerosol Sampling ◽  
X Ray Diffraction ◽  
Analytical Strategy ◽  
X Ray ◽  
Analytical Interference ◽  
Diffraction Patterns ◽  
Artifact Formation ◽  
Thermally Treated

Characterization of some crystalline species present in atmospheric particulate matter can be investigated by an X-ray diffractometric technique. According to the analytical strategy, filtering media suitable for collecting airborne particles must be selected. In order to recognize the X-ray diffraction patterns and consequently the inherent analytical interference of filtering media, a systematic X-ray diffraction evaluation of several substrates was performed. Although artifact formation during ambient sampling can occur on quartz and glass fiber filters, these filters were also included in the diffractometric characterization. In this work, commercial filters were thermally treated and submitted to X-ray diffraction scanning. Results have shown pronounced variations in the diffractometric profiles of each thermally treated substrate. The selection criteria for choosing the filtering media was established by considering their chemical and physical properties and also the crystalline species to be collected on them.

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