Sveite from the Northeastern San Joaquin Valley, California

2021 ◽  
Author(s):  
Ronald C. Peterson ◽  
Robert C. Graham ◽  
Jarel O. Ervin ◽  
Igor S. Kozin ◽  
James O. Sickman ◽  
...  
Keyword(s):  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Mineral Occurrence ◽  
Diffraction Patterns ◽  
Biogenic Source ◽  
Water Extractable ◽  
Structure Water ◽  
Bird Feces

ABSTRACT Sveite [KAl7(NO3)4(OH)16Cl2·8H2O] first described from Venezuela and material recently collected from northern California have similar X-ray diffraction patterns and chemical compositions. The main difference in the chemical composition is the absence of significant chlorine and sulfate in the sveite from California. The changes observed by X-ray diffraction upon hydration and the SEM images of the crystals suggest a layered atomic structure. Water-extractable NO3 in the Venezuelan sveite sample is isotopically enriched in δ15N and δ18O and likely was affected by the microbial process of denitrification. In contrast, the extractable nitrate from the California sveite is less isotopically enriched than the Venezuelan mineral and there is only modest evidence that denitrification had affected its isotopic composition. Overall, the nitrate in the California sveite is isotopically similar to nitrate present in acidic soils overlying the mineral occurrence, suggesting a general biogenic source of uric acid from bird feces for the mineral-bound nitrogen.

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.

Structural and electrical properties of Cu-doped Ni–Zn nanocrystalline ferrites for MLCI applications

2017 ◽  
Vol 31 (33) ◽  
pp. 1750318 ◽  
Author(s):  
D. Venkatesh ◽  
K. V. Ramesh
Keyword(s):  
Electrical Properties ◽  
Cation Distribution ◽  
Tetrahedral Site ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Phase Spinel ◽  
Diffraction Patterns

Polycrystalline Cu substituted Ni–Zn ferrites with chemical composition Ni[Formula: see text]Zn[Formula: see text]-Cu[Formula: see text]Fe2O4 (x = 0.00 to 0.25 in steps of 0.05) have been prepared by citrate gel autocombustion method. The samples for electrical properties have been sintered at 900[Formula: see text]C for 4 h. The X-ray diffraction patterns of all samples indicate the formation of single phase spinel cubic structure. The value of lattice parameter is decreases with increasing Cu concentration. The estimated cation distribution can be derived from X-ray diffraction intensity calculations and IR spectra. The tetrahedral and octahedral bond lengths, bond angles, cation–cation and cation–anion distances were calculated by using experimental lattice parameter and oxygen positional parameters. It is observed that Cu ions are distributed in octahedral site and subsequently Ni and Fe ions in tetrahedral site. The grain size of all samples has been calculated by Scanning Electron Microscopy (SEM) images. The variations in DC electrical resistivity and dielectric constant have been explained on the basis of proposed cation distribution.

Study of diffraction data sets using factor analysis: a new technique for comparing mineralogical and geochemical data and rapid diagnostics of the mineral composition of large collections of rock samples

2019 ◽  
Vol 34 (S1) ◽  
pp. S59-S70 ◽  
Author(s):  
Ekaterina Fomina ◽  
Evgeniy Kozlov ◽  
Svetlana Ivashevskaja
Keyword(s):  
Geochemical Data ◽  
Chemical Compositions ◽  
Data Sets ◽  
Rapid Diagnostics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Short Period ◽  
Diffraction Patterns ◽  
A New Technique

This paper presents an example of comparing geochemical and mineralogical data by means of the statistical analysis of the X-ray diffraction patterns and the chemical compositions of bulk samples. The proposed methodology was tested on samples of metasomatic rocks from two geologically different objects. Its application allows us to mathematically identify all the main, secondary and some accessory minerals, to qualitatively estimate the contents of these minerals, as well as to assess their effect on the distribution of all petrogenic and investigated trace elements in a short period of time at the earliest stages of the research. We found that the interpretation of the results is significantly influenced by the number of samples studied and the quality of diffractograms.

Electrosynthesis and Studies on CdZnSe Thin Films

2011 ◽  
Vol 15 (1) ◽  
pp. 37-42
Author(s):  
T. Mahalingam ◽  
V. Dhanasekaran ◽  
S. Rajendran ◽  
R. Chandramohan ◽  
Luis Ixtlilco ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Band Gap ◽  
Ph Value ◽  
Bath Temperature ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
Sem Images ◽  
X Ray ◽  
Predominant Orientation ◽  
Diffraction Patterns

Electrodeposited CdZnSe thin films have been prepared at various bath temperatures. The thickness of the films was estimated between 850 nm and 1500 nm by stylus method. The X-ray diffraction patterns revealed that the polycrystalline nature with cubic structure of CdZnSe alloy thin films. Microstructural properties such as, crystallite size, dislocation density, microstrain and number of crystallites per unit area were calculated using predominant orientation of the films. SEM images revealed that the surface morphology could be tailored suitably by adjusting the pH value during deposition. The surface roughness of the film was estimated using topographical studies. Optical properties of the film were analyzed from absorption and transmittance studies. Optical band gap of the films increased from 1.67 to 1.72 eV with the increase of bath temperature from 30 to 90℃. The optical constants (refractive index (n) and extinction coefficient (k)) of CdZnSe thin films were evaluated using optical studies.

Synthesis and characterization of a silylated Brazilian clay mineral surface

2014 ◽  
Vol 68 (7) ◽  
Author(s):  
Márcia Silva ◽  
Saloana Gomes ◽  
Maria Fonseca ◽  
Kaline Sousa ◽  
José Espínola ◽  
...  
Keyword(s):  
Clay Mineral ◽  
Solid State Nmr ◽  
Textural Properties ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Diffraction Patterns ◽  
Trimethoxy Silane

AbstractClay mineral containing kaolinite, illite and montmorillonite was organofunctionalized with silylating agents: (3-aminopropyl)triethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane and (3-mercaptopropyl)trimethoxy-silane, to yield three hybrids labelled Clay1, Clay2 and Clay3, respectively. These solids were characterized using elemental analysis, thermogravimetry, X-ray diffractometry, infrared spectroscopy, scanning electron micrograph, and 29Si and 27Al solid state NMR. Immobilized quantities of the organic groups were 0.66 mmol g−1, 0.48 mmol g−1 and 0.88 mmol g−1 for Clayx (x = 1–3), respectively. X-ray diffraction patterns confirmed the immobilization of silanes onto the surface without changes in the textural properties of the clay mineral as noted from the SEM images. Spectroscopic measurements were in agreement with the covalent bonding between the silanes and the hydroxyl groups deposited on the surface. The new hybrids were utilized as adsorbents of cobalt in aqueous solution, with retention values of 0.78 mmol g−1, 1.1 mmol g−1 and 0.70 mmol g−1 for Clayx (x = 1–3), respectively.

Alumina Residue Characterization to Produce Tubular Ceramic Membranes

2012 ◽  
Vol 727-728 ◽  
pp. 1508-1513 ◽  
Author(s):  
Iliana Oliveira Guimarães ◽  
Hélio Lucena Lira ◽  
Sidinei Kleber da Silva ◽  
Suellen Lisboa Dias ◽  
Rosa do Carmo de Oliveira Lima
Keyword(s):  
Electrostatic Precipitator ◽  
Raw Materials ◽  
Environmental Issues ◽  
Ceramic Membranes ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Calcination Process ◽  
X Ray ◽  
Two Samples

ndustrial wastes recycling become attractive due to raw materials economy (sustainability) and environmental issues. This research objective was to characterize a residue generated during the alumina calcination process (electrostatic precipitator dust), to be applied on the development of tubular ceramic membranes. In this context, two samples were analyzed, a crude residue (sample A) as supplied by the industry and other calcined residue (sample B). As verified by X-ray fluorescence spectroscopy by dispersive energy (XDE), the samples A and B showed a high content of alumina in chemical compositions, both close to 96%. Gibbsite and α-alumina crystalline phases were identified by X-ray diffraction (XRD) in the samples. At scanning electron microscopy (SEM) images, could be observed agglomerates of particles with asymmetric shapes and a wide particle size distribution like was confirmed by laser diffraction, which showed that the particles diameters remained almost unchanged after calcination at 700°C. Results revealed no significant differences between samples characteristics, indicating that the crude and calcined residues could be used to prepare ceramic membranes.

Investigation on structure of BaTi1−x NbxO3 compound prepared by rotary-hydrothermal synthesis methods

2014 ◽  
Vol 32 (3) ◽  
pp. 430-435 ◽  
Author(s):  
Arsia Khanfekr ◽  
Morteza Tamizifar ◽  
Rahim Naghizadeh
Keyword(s):  
Electron Microscope ◽  
Hydrothermal Reaction ◽  
Phase Evolution ◽  
Synthesis Methods ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractBaTi1−x NbxO3 compounds (with x = 0.0, 0.01, 0.03, 0.06, and 0.09) were synthesized by rotary-hydrothermal (RH) method. The process was conducted at 180 °C for 5 hours in a Teflon vessel that was rotated at a speed of 160 rpm during the hydrothermal reaction. The effects of donor concentration on the structure and properties of BaTi1−x NbxO3 compounds were investigated. The experiments for the BaTiO3±Nb2O3 system produced by a solid state reaction at high temperature at different concentrations of niobium, with the use of RH processing have not been reported in previous works. For the phase evolution studies, X-ray diffraction patterns (XRD) were analyzed and Raman spectroscopy measurements were performed. The transmission electron microscope (TEM) and the field emission scanning electron microscope (FE-SEM) images were taken for the detailed analysis of the grain size, surface and morphology of the compound.

scholarly journals Chromium (III) Oxide Nanostructures Synthesized from Vernonia Amygdalina Leaves Extract

2020 ◽  
Vol 10 (1) ◽  
pp. 1856-1861
Keyword(s):  
Fourier Transform ◽  
Average Crystallite Size ◽  
Fourier Transform Infrared ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Vernonia Amygdalina ◽  
Sem Images ◽  
X Ray ◽  
Chloride Hexahydrate ◽  
Diffraction Patterns

This contribution reports first time synthesis of Cr2O3 nanostructures from chromium (III) chloride hexahydrate precursor using Vernonia amygdalina leaves extract as a reducing and stabilizing agent. Powder X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy techniques were used to study the structural and morphological properties of the as-synthesized Cr2O3 nanostructures. Powder X-ray diffraction patterns spectral analysis showed that hexagonal Cr2O3 nanostructures with an average crystallite size of 23.4 nm were synthesized with the minor appearance of CrO2. SEM images showed that the synthesized nanomaterials are granules. Fourier-transform infrared spectra represent a sharp absorption band at 552 cm-1, which indicates Cr-O-Cr vibrational and stretching modes.

Production of Amorphous and Crystalline Silica from Philippine Waste Rice Hull

2015 ◽  
Vol 1098 ◽  
pp. 80-85
Author(s):  
Emie Salamangkit Mirasol ◽  
Rinlee Butch M. Cervera
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Rice Hull ◽  
Rice Grain ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structural Result ◽  
X Ray ◽  
Structure Morphology ◽  
Diffraction Patterns

Rice husk is the covering of rice seeds and a by-product of milling rice grain. This study is conducted to investigate the production of silica (SiO2) formed from waste rice hull (RH) at different processing temperatures and study its structure, morphology, and thermal properties. Thermal analysis by thermogravimetric analysis (TGA) of the dried RH showed two mass-loss steps associated to the moisture desorption and thermal decomposition. Powder X-ray diffraction patterns of the rice hull calcined at 550oC showed a purely amorphous SiO2structure while those calcined for 900oC for 1 hour and for 3 hours showed a glass-ceramics and crystalline SiO2structure, respectively. This structural result is supported by the results obtained from the FTIR and Raman analyses of the samples. On the other hand, the Scanning electron microscopy (SEM) images showed the morphology of the samples revealing an increasing particle and grain size of the samples calcined at higher temperatures and longer heat treatment duration. In addition, Energy dispersive X-ray (EDX) spectra of both amorphous and crystalline SiO2samples confirm that the sample contains mostly silicon and oxygen. Thus, in this study, the desired form of either amorphous or crystalline SiO2from waste rice hull can be successfully obtained by controlled heat treatment.

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