Distribution, composition, and source of the White River Ash, Yukon Territory

1969 ◽  
Vol 6 (1) ◽  
pp. 109-116 ◽  
Author(s):  
J. F. Lerbekmo ◽  
F. A. Campbell
Keyword(s):  
Chemical Composition ◽  
Yukon Territory ◽  
Aerial Photographs ◽  
Average Chemical Composition ◽  
Large White ◽  
X Ray ◽  
White River ◽  
Significant Difference ◽  
Target Source ◽  
Distribution Composition

The White River Ash is a bi-lobate 1500 year old deposit occupying at least 6 cubic miles and covering some 125 000 square miles of southern Yukon and eastern Alaska. Sixty-six samples were collected at 5-mile intervals, principally along two traverses 120 miles apart across the main lobe, and subjected to X-ray fluorescence and petrographic analysis.The ash is a rhyodacite composed of glass (n = 1.502), andesine, hornblende, hypersthene, and magnetite. The average chemical composition is SiO2 = 67.4, Al2O3 = 15.1, TiO2 = 0.5, MgO = 2.0, FeO = 2.0, Fe2O3 = 2.2, Na2O = 4.1, K2O = 2.5 and CaO = 4.1, but there is a significant difference between the two traverses owing to the increase in glass relative to crystal components downwind.A synthesis of the distribution of the ash permitted the drawing of a 5 by 12 miles 'target' source rectangle in the St. Elias Range between Mts. Natazhat and Bona in Alaska. Aerial photographs revealed a suspect mound 0.4 miles in diameter beside the Klutlan Glacier. Access by helicopter showed the mound to be a flat cone of large White River pumice fragments. It is believed that the vent lies beneath the glacier next to the cone.

Surface Roughness on the Slots and Wings of Various Ceramic Self-Ligating Brackets and their Potential Concern on Biofilm Formation

2020 ◽  
Vol 44 (6) ◽  
pp. 451-458
Author(s):  
Ki-Ho Park ◽  
Se Jik Han ◽  
Samjin Choi ◽  
Kyung Sook Kim ◽  
Steven Park ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Chemical Composition ◽  
Biofilm Formation ◽  
Control Group ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Significant Difference ◽  
Orthodontic Materials

Objective: The surface roughness of various orthodontic materials could affect biofilm formation and friction. The purpose of this study was to examine the surface roughness and chemical composition of the slots and wings of several ceramic self-ligating brackets. Study design: Four types of ceramic self-ligating brackets were separated into experimental groups (DC, EC, IC, and QK) while a metal self-ligating bracket (EM) was used as the control group. Atomic force microscopy and energy-dispersive x-ray spectroscope were used to examine the surface roughness and chemical composition of each bracket slot and wing. Results: The control group was made of ferrum and chrome while all the experimental groups were comprised of aluminum and oxide. There was a statistically significant difference in the roughness average (Sa) among the various self-ligating brackets (p< 0.001 in slots and p<0.01 in the wing). The slots in the EC group had the lowest Sa, followed by the DC, IC, control, and QK groups. The wings in the IC group had the lowest Sa, followed by the EC, DC, control, and QK groups. Conclusions: There is a significant difference in the surface roughness of the slots and wings among several types of ceramic self-ligating brackets.

scholarly journals Fluctuations in Chemical Composition of M7C3 Carbides in the Soft Annealed Nc11lv/D2 Steel

2014 ◽  
Vol 14 (1) ◽  
pp. 24-30
Author(s):  
T. Hryniewicz ◽  
T. Nykiel
Keyword(s):  
Chemical Composition ◽  
Tool Steel ◽  
Alloying Elements ◽  
Average Chemical Composition ◽  
X Ray ◽  
Study Results ◽  
Differentiation Degree ◽  
Made In Usa ◽  
D2 Steel ◽  
Made In

ABSTRACT The paper presents the study results on chemical composition of the coarse primary M7C3 carbides occurring in the soft annealed NC11LV/D2 tool steel consisting of: 1.53% C; 11.65% Cr; 0.01% W; 0.81% Mo; 0.068% V; (balance iron plus admixtures), used for cold operation. The microanalyzer of type SEMPROBE Su-30, French made by CAMECA Co., equipped with two WDS X-ray spectrometers and an EDS VOYAGER 3 100, NORAN Instruments Co., made in USA. It was found that out of the three alloying elements occurring in the big carbides of the annealed NC11LV/D2 steel, i.e. Cr, Mo, and V, the chromium appears to be the most uniformly distributed. The big carbides vary concerning C, Cr, Mo, V; the greatest differentiation degree of the contents of Mo and Cr, and the least - of vanadium. The average chemical composition of the big/coarse carbides is as follows: C = 9.42±1.28%; Cr = 44.17±2.95%; Mo = 4.48±3.52%; V = 4.53±0.31%; balance Fe.

X-ray microanalysis of mixed saliva with fluorosis

2019 ◽  
pp. 38-41
Author(s):  
A.A. Musiev ◽  
A.G. Volkov ◽  
N.Zh. Dikopova ◽  
N.V. Makarenko ◽  
T.V. Budina ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Oral Fluid ◽  
Phosphorus Content ◽  
Chemical Elements ◽  
Dental Fluorosis ◽  
Fluorine Content ◽  
X Ray ◽  
Endemic Focus ◽  
Significant Difference ◽  
Mixed Saliva

The aim of this research was to study patients with the chemical composition of mixed saliva in fluorosis using X-ray microanalysis both living in the endemic center of fluorosis and leaving it. The research involved 64 patients with dental fluorosis, all male, age — 20—35 years. To accomplish the purpose of the study, two groups were formed from them: the first group included 33 people with dental fluorosis of dashed and spotted forms, living in an endemic center of fluorosis (Krasnogorsk district, Moscow region). The second group included 31 people with dental fluorosis who left the endemic focus and live in areas with normal fluoride content in water. Results. According to the content in the mixed saliva of a number of chemical elements, no significant difference (p>0.05) was found between the studied groups. These elements include: carbon, nitrogen, oxygen, silicon, sulfur, and calcium. However, the content of other chemical elements in the oral fluid was observed statistically significant differences (p<0.05) between patients with fluorosis living in the focus of endemic lesion and patients who migrated beyond it. Thus, in the first group, in the studied saliva, the fluorine content was 42% higher than in the second. Also in this group, compared with the second, the phosphorus content was higher 18%, chlorine and potassium 27%. The content of sodium in the first group was 27% lower than in the second.

Geochemical and mineralogical characterization of the Jabal Al-Harad kaolin deposit, southern Jordan, for its possible utilization

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 301-314 ◽  
Author(s):  
M. Gougazeh ◽  
J.-Ch. Buhl
Keyword(s):  
Chemical Composition ◽  
Average Chemical Composition ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Basement Rocks ◽  
Mineral Assemblages ◽  
Fired Bricks ◽  
Economic Concentration ◽  
Kaolin Deposit

AbstractKaolin is found in deposits of economic concentration in the Jabal Al-Harad/ Batn El-Ghoul area in southern Jordan. Ten representative kaolin samples were collected from the area and investigated for their mineralogical and chemical composition. Mineral characterization was carried using X-ray powder diffraction (XRD), thermogravimetrical analysis (TGA), differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). X-ray fluorescence (XRF) studies were conducted to determine the chemical composition of the kaolin deposits. Kaolinite was the predominant mineral, followed by quartz, with traces of illite-muscovite, Fe-bearing minerals (hematite), anatase and feldspar. The average chemical composition of the kaolin samples was 58.02 wt.% SiO2, 28.00% Al2O3, 1.48% Fe2O3, 1.26% TiO2and 0.41% K2O (ignited basis). Dehydroxylation and mullitization temperatures (from DTA) were close to the theoretical values. Hexagonal booklets and stacks of kaolinite, as well as individual platelets, were present in the Jabal Al-Harad kaolin. Based on granulometric and descriptive mineralogical analyses, the mineral assemblages and kaolinite morphology, the Jabal Al-Harad kaolin deposit is thought to have originated from greatly weathered surfaces related to the Precambrian basement rocks. The kaolin was found to be suitable for manufacturing of common bricks, medium-fired bricks and sanitary ware, although a beneficiation process would be required; it could also be used in the refractory, white cement, paper and advanced ceramic industries.

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

2020 ◽  
Vol 58 (5) ◽  
pp. 549-562
Author(s):  
Anatoly V. Kasatkin ◽  
Fabrizio Nestola ◽  
Radek Škoda ◽  
Nikita V. Chukanov ◽  
Atali A. Agakhanov ◽  
...  
Keyword(s):  
New Mineral ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Average Chemical Composition ◽  
X Ray ◽  
Conchoidal Fracture ◽  
Icp Ms ◽  
Optical Axes ◽  
Mohs Hardness ◽  
Khyber Pakhtunkhwa Province

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I > 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

Preparation and properties of green rust type substances

1987 ◽  
Vol 52 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Jaroslav Vinš ◽  
Jan Šubrt ◽  
Vladimír Zapletal ◽  
František Hanousek
Keyword(s):  
Chemical Composition ◽  
Electron Diffraction ◽  
Green Rust ◽  
X Ray ◽  
Synthesis Conditions ◽  
Diffraction Patterns

A method has been worked out for the reproducible preparation of Green Rust substances involving SO42-, Cl-, Br-, and I- anions. The chemical composition of the substances prepared has been followed in dependence on the synthesis conditions. The powder X-ray and electron diffraction patterns and infrared and Moessbauer spectra have been measured and discussed.

Energy-Dispersive X-ray Fluorescence Analysis as a Rapid Method for Identifying Tephras

1983 ◽  
Vol 19 (2) ◽  
pp. 201-211 ◽  
Author(s):  
A. B. Cormie ◽  
D. E. Nelson
Keyword(s):  
Reliable Method ◽  
Fluorescence Analysis ◽  
Energy Dispersive ◽  
Bulk Glass ◽  
X Ray ◽  
Additional Tool ◽  
White River ◽  
Routine Identification ◽  
Weathering Effects ◽  
Mount St Helens

AbstractThe use of energy-dispersive X-ray fluorescence analysis (XES) for the routine identification of three tephras (Mazama, Bridge River, Mount St. Helens Yn) commonly found in archeological sites in British Columbia has been investigated. Researchers have often assumed that chemical analysis of bulk samples of glass separates would be hampered by contamination and weathering effects. Our results indicate that XES of bulk glass separates provides a very reliable method for rapidly identifying the three tephras in question, even with a very simple sample preparation. This should enable persons not skilled in geology or in tephrochronology to collect and to identify samples of these tephras. Finally, as a part of the study, similar measurements were made on the separated glass portions of these three tephras and of three others (Glacier Peak B and G, White River) from northwest North America. The results suggest that this method may provide tephrochronologists with a useful additional tool for studying tephras in other regions.

scholarly journals Crystal structure of pimecrolimus Form B, C43H68ClNO11

2021 ◽  
Vol 36 (1) ◽  
pp. 35-42
Author(s):  
Shivang Bhaskar ◽  
Joseph T. Golab ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Density Functional ◽  
Van Der Waals Interactions ◽  
Powder Diffraction File ◽  
X Ray ◽  
Weak Intermolecular Interactions ◽  
Significant Difference ◽  
Atomic Coordinates ◽  
Solid State Conformation

The crystal structure of pimecrolimus Form B has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Pimecrolimus crystallizes in the space group P21 (#4) with a = 15.28864(7), b = 13.31111(4), c = 10.95529(5) Å, β = 96.1542(3)°, V = 2216.649(9) Å3, and Z = 2. Although there are an intramolecular six-ring hydrogen bond and some larger chain and ring patterns, the crystal structure is dominated by van der Waals interactions. There is a significant difference between the conformation of the Rietveld-refined and the DFT-optimized structures in one portion of the macrocyclic ring. Although weak, intermolecular interactions are apparently important in determining the solid-state conformation. The powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-066-1619. This study provides the atomic coordinates to be added to the PDF entry.

scholarly journals Geochemistry and Mineralogy of Ice-Dammed Lake Sediments of the Lębork Deposit

2021 ◽  
Author(s):  
Radosław Rogoziński ◽  
Alina Maciejewska
Keyword(s):  
Chemical Composition ◽  
Lake Sediments ◽  
Inductively Coupled Plasma ◽  
Mineralogical Composition ◽  
Raw Material ◽  
Element Analysis ◽  
X Ray ◽  
Dominant Component ◽  
Clay Deposits ◽  
Dammed Lake

AbstractVarved clay deposits from ice-dammed lakes are a particularly important and broadly applied raw material used for the production of high-quality ceramics (red bricks, roof tiles, etc.), but the mineralogy and geochemistry of these sediments are not fully understood. The aim of the present study was to determine the chemical and mineralogical composition of ice-dammed lake sediments of the Lębork deposit. Major-element analysis of the compositions of selected samples from the ice-dammed lake clays was performed by X-ray fluorescence (XRF) and trace elements were determined by inductively coupled plasma-mass spectrometry. The mineralogical composition of clay samples was determined by X-ray diffraction (XRD). Analyses of the chemical composition of the ice-dammed lake clays of the Lębork deposit showed that the dominant component was SiO2 with a mean content of 56.13 wt.%; the second most abundant component was Al2O3, with a mean content for the entire deposit of 11.61 wt.%. Analysis by ICP-MS indicated the presence of rare earth elements (REE), e.g. cerium, neodymium, lanthanum, and praseodymium; their mean contents are: 56.9, 27.0, 26.3, and 7.3 ppm, respectively. Mineralogical analysis of the varved clays identified quartz, muscovite, calcite, and clay minerals – illite, kaolinite, and montmorillonite. The material filling the Lębork basin is characterized by small lateral and vertical variability in chemical composition. The results of the present study may be of considerable importance in determining the parent igneous, metamorphic, and sedimentary rocks, the weathering products of which supplied material to the ice-dammed lake, as well as in determining the mechanisms and character of the sedimentation process itself.

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