Fragmentation, nucleation and migration of crystals and bubbles in the Bishop Tuff rhyolitic magma

2004 ◽  
Vol 95 (1-2) ◽  
pp. 375-390 ◽  
Author(s):  
Guilherme A. R. Gualda ◽  
David L. Cook ◽  
Rahul Chopra ◽  
Liping Qin ◽  
Alfred T. Anderson ◽  
...  
Keyword(s):  
Size Distributions ◽  
Bishop Tuff ◽  
Volumetric Fraction ◽  
Slow Cooling ◽  
Magma Body ◽  
Rhyolitic Magma ◽  
X Ray ◽  
High Silica ◽  
And Migration ◽  
Crystal Content

ABSTRACTThe Bishop Tuff (USA) is a large-volume, high-silica pyroclastic rhyolite. Five pumice clasts from three early stratigraphic units were studied. Size distributions were obtained using three approaches: (1) crushing, sieving and winnowing (reliable for crystals >100 μm); (2) microscopy of ∼1 mm3 fragments (preferable for crystals <100 μm); and (3) computerised X-ray microtomography of ∼1 cm3 pumice pieces.Phenocryst fragments coated with glass are common, and the size distributions for all crystals are concave-upward, indicating that crystal fragmentation is an important magmatic process.Three groups are recognised, characterised by: (1) high-density (0·759–0·902 g cm−3), high-crystal content (14·4–15·3 wt.%) and abundant large crystals (>800 μm); concave-downward size distributions for whole crystals indicate late-stage growth with limited nucleation, compatible with the slow cooling of a large, gas-saturated, stably stratified magma body; (2) low-density (0·499 g cm −3), low-crystal content (6·63 wt.%) and few large crystals; the approximately linear size distribution reveals that nucleation was locally important, perhaps close to the walls; and (3) intermediate characteristics in all respects.The volumetric fraction of bubbles inversely correlates with the number of large crystals. This is incompatible with isobaric closed-system crystallisation, but can be explained by sinking of large crystals and rise of bubbles in the magma

Fragmentation, nucleation and migration of crystals and bubbles in the Bishop Tuff rhyolitic magma

2004 ◽  
Author(s):  
Guilherme A. R. Gualda ◽  
David L. Cook ◽  
Rahul Chopra ◽  
Liping Qin ◽  
Alfred T. Anderson ◽  
...  
Keyword(s):  
Bishop Tuff ◽  
Rhyolitic Magma ◽  
And Migration

scholarly journals Review of Respirable Coal Mine Dust Characterization for Mass Concentration, Size Distribution and Chemical Composition

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 426
Author(s):  
Behrooz Abbasi ◽  
Xiaoliang Wang ◽  
Judith C. Chow ◽  
John G. Watson ◽  
Bijan Peik ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Particle Size ◽  
Real Time ◽  
Coal Mine ◽  
Energy Dispersive ◽  
Size Distributions ◽  
X Ray ◽  
Membrane Filters ◽  
Mine Dust ◽  
Mass Concentrations

Respirable coal mine dust (RCMD) exposure is associated with black lung and silicosis diseases in underground miners. Although only RCMD mass and silica concentrations are regulated, it is possible that particle size, surface area, and other chemical constituents also contribute to its adverse health effects. This review summarizes measurement technologies for RCMD mass concentrations, morphology, size distributions, and chemical compositions, with examples from published efforts where these methods have been applied. Some state-of-the-art technologies presented in this paper have not been certified as intrinsically safe, and caution should be exerted for their use in explosive environments. RCMD mass concentrations are most often obtained by filter sampling followed by gravimetric analysis, but recent requirements for real-time monitoring by continuous personal dust monitors (CPDM) enable quicker exposure risk assessments. Emerging low-cost photometers provide an opportunity for a wider deployment of real-time exposure assessment. Particle size distributions can be determined by microscopy, cascade impactors, aerodynamic spectrometers, optical particle counters, and electrical mobility analyzers, each with unique advantages and limitations. Different filter media are required to collect integrated samples over working shifts for comprehensive chemical analysis. Teflon membrane filters are used for mass by gravimetry, elements by energy dispersive X-ray fluorescence, rare-earth elements by inductively coupled plasma-mass spectrometry and mineralogy by X-ray diffraction. Quartz fiber filters are analyzed for organic, elemental, and brown carbon by thermal/optical methods and non-polar organics by thermal desorption-gas chromatography-mass spectrometry. Polycarbonate-membrane filters are analyzed for morphology and elements by scanning electron microscopy (SEM) with energy dispersive X-ray, and quartz content by Fourier-transform infrared spectroscopy and Raman spectroscopy.

scholarly journals XPS Modeling of Immobilized Recombinant Angiogenin and Apoliprotein A1 on Biodegradable Nanofibers

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 879
Author(s):  
Anton Manakhov ◽  
Elizaveta Permyakova ◽  
Sergey Ershov ◽  
Svetlana Miroshnichenko ◽  
Mariya Pykhtina ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Growth Factor ◽  
Photoelectron Spectroscopy ◽  
Antioxidant Activities ◽  
Fluorescent Microscopy ◽  
X Ray ◽  
Vascular Growth ◽  
Vascular Growth Factor ◽  
And Migration ◽  
Protein Density

The immobilization of viable proteins is an important step in engineering efficient scaffolds for regenerative medicine. For example, angiogenin, a vascular growth factor, can be considered a neurotrophic factor, influencing the neurogenesis, viability, and migration of neurons. Angiogenin shows an exceptional combination of angiogenic, neurotrophic, neuroprotective, antibacterial, and antioxidant activities. Therefore, this protein is a promising molecule that can be immobilized on carriers used for tissue engineering, particularly for diseases that are complicated by neurotrophic and vascular disorders. Another highly important and viable protein is apoliprotein A1. Nevertheless, the immobilization of these proteins onto promising biodegradable nanofibers has not been tested before. In this work, we carefully studied the immobilization of human recombinant angiogenin and apoliprotein A1 onto plasma-coated nanofibers. We developed a new methodology for the quantification of the protein density of these proteins using X-ray photoelectron spectroscopy (XPS) and modeled the XPS data for angiogenin and apoliprotein A1 (Apo-A1). These findings were also confirmed by the analysis of immobilized Apo-A1 using fluorescent microscopy. The presented methodology was validated by the analysis of fibronectin on the surface of plasma-coated poly(ε-caprolactone) (PCL) nanofibers. This methodology can be expanded for other proteins and it should help to quantify the density of proteins on surfaces using routine XPS data treatment.

A New X-Ray Scattering Method for Determining Pore-Size Distribution in Low-k Thin Films

2001 ◽  
Vol 714 ◽  
Author(s):  
Kazuhiko Omote ◽  
Shigeru Kawamura
Keyword(s):  
Thin Films ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Gas Adsorption ◽  
Size Distributions ◽  
X Ray ◽  
X Ray Scattering ◽  
Pore Size Distributions ◽  
Scattering Technique ◽  
Ray Scattering

ABSTRACTWe have successively developed a new x-ray scattering technique for a non-destructive determination of pore-size distributions in porous low-κ thin films formed on thick substrates. The pore size distribution in a film is derived from x-ray diffuse scattering data, which are measured using offset θ/2θ scans to avoid strong specular reflections from the film surface and its substrate. Γ-distribution mode for the pores in the film is used in the calculation. The average diameter and the dispersion parameter of the Γ-distribution function are varied and refined by computer so that the calculated scattering pattern best matches to the experimental pattern. The technique has been used to analyze porous methyl silsesquioxane (MSQ) films. The pore size distributions determined by the x-ray scattering technique agree with that of the commonly used gas adsorption technique. The x-ray technique has been also used successfully determine small pores less than one nanometer in diameter, which is well below the lowest limit of the gas adsorption technique.

Growth defects and infrared spectra analysis of CePO4single crystals

2005 ◽  
Vol 38 (4) ◽  
pp. 675-677 ◽  
Author(s):  
Kunpeng Wang ◽  
Jianxiu Zhang ◽  
Jiyang Wang ◽  
Changshui Fang ◽  
Wentao Yu ◽  
...  
Keyword(s):  
Slow Cooling ◽  
Spectra Analysis ◽  
X Ray ◽  
Cell Parameters ◽  
Growth Defects ◽  
Cooling Method ◽  
Good Crystalline Quality ◽  
Growth Habits ◽  
Top Seeded Solution Growth

High-quality CePO4single crystals (monazite) were grown by the flux TSSG (top-seeded-solution growth) slow-cooling method. The X-ray powder diffraction pattern shows good crystalline quality of the crystals and the various peaks were assigned. The unit-cell parameters were calculated using theDICVOL90andTERORcomputer programs. The concentrations of all elements in the crystals were measured by electron probe microanalysis. Growth habits were deduced by the Bravais–Friedel Donnay–Harker (BFDH) method and macro-defects in the crystals are discussed. An infrared spectrum of the crystal was recorded in the frequency range of 300 to 1600 cm−1and all vibration frequency peaks were assigned.

scholarly journals СИНТЕЗ И ИССЛЕДОВАНИЕ СТЕКЛООБРАЗОВАНИЯ В СИСТЕМЕ AS2S3-ERS

2021 ◽  
Vol 7 (5(59)) ◽  
pp. 28-31
Author(s):  
ТЕЙМУР МАМЕД ИЛЬЯСЛИ ◽  
ДУНИЯ ТАЛЕХ ГАСАНОВА ◽  
ИМИР ИЛЬЯС АЛИЕВ
Keyword(s):  
Chemical Analysis ◽  
Solid Solutions ◽  
Glass Formation ◽  
Room Temperature ◽  
Slow Cooling ◽  
X Ray ◽  
Physico Chemical

To determine the area of glass formation in the system As2S3-ErS were synthesized alloys in the range of concentrations 0-30 mol. % ErS. The methods of physico-chemical analysis of differential-thermal (DTA), X-ray phase (RFA), microstructural (MCA) analyzes, as well as the measurement of microhardness and density determined the area of the glass and studied them physicо-chemical propertes. It is established that in the system As2S3-ErS on the basis of As2S3 during slow cooling the area of the glass reaches 17 mol. % ErS. Alloys in the concentration range 20-30 mol. % ErS are glass-crystalline. In the system at room temperature solid solutions on the basis of As2S3 are distributed up to 2.5 mol.% ErS, and on the basis of solid solutions ErS are practically not installed.

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