scholarly journals Kristalinitas Abu Vulkanik Gunung Soputan dan Implikasinya Terhadap Perilaku Eksplosif pada Erupsi Tahun 2016 dan 2018

2021 ◽  
Vol 21 (1) ◽  
pp. 49
Author(s):  
Maria D. Bobanto ◽  
Ferdy Ferdy ◽  
Guntur Pasau ◽  
D.D Tampemawas ◽  
A. Saefuloh ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Crystal Size ◽  
Explosive Eruption ◽  
Crystallinity Index ◽  
X Ray ◽  
High Crystallinity ◽  
Block Form ◽  
Small Crystals ◽  
Solid Form ◽  
Brittle Fragmentation

Gunung Soputan adalah gunung basaltik dengan tipe erupsi eksplosif. Tipikal eksplosif berkaitan dengan karakter magma. Penelitian ini bertujuan untuk mengkaji kristalinitas abu vulkanik Gunung Soputan tahun 2016 dan 2018 dan implikasinya terhadap perilaku eksplosifnya. Kristalinitas abu vulkanik dikarakterisasi menggunakan peralatan difraktometer sinar X. Indeks kristalinitas dikalkulasi menggunakan persamaan Soltys dan ukuran kristal dikomputasi dengan persamaan Debye-Scherrer. Morfologi partikel abu dikarakterisasi menggunakan SEM. Hasil karakterisasi menunjukkan bahwa abu Soputan tahun 2016 dan 2018 memiliki indeks kristalinitas yang tinggi dan mengandung sejumlah kristal berukuran kecil serta memiliki dua bentuk morfologi yaitu bentuk padat dan blok bervesikular untuk abu hasil erupsi 4 Januari 2016, dan bentuk padat dan blok untuk abu hasil erupsi 6 Februari 2016 dan 3 Oktober 2018. Kristalinitas yang tinggi menyebabkan magma Soputan memiliki viskositas yang memadai untuk terjadinya  erupsi yang eksplosif. Karakter eksplosif Gunung Soputan terekam dalam morfologi abu vulkaniknya.Kata kunci: Abu vulkanik; erupsi eksplosif; fragmentasi getas; indeks kristalinitasCristallinity of Volcanic Ash of Mount Soputan and Its Implication to Explosive Behaviour on Eruption of 2016 and 2018ABSTRACTMount Soputan is a basaltic mountain with an explosive eruption type. Typical explosives relate to the character of the magma. This study aims to examine the crystallinity of Mount Soputan's volcanic ash in 2016 and 2018 and its implications for its explosive behavior. The crystallinity of volcanic ash was characterized using an X-ray diffractometer. The crystallinity index was calculated using the Soltys equation and the crystal size computed using the Debye-Scherrer equation. The morphology of the ash particles was characterized using SEM. The characterization results show that the 2016 and 2018 Soputan ash has a high crystallinity index and contains a number of small crystals and has two morphological forms, namely solid form and vesicular block for ash from the eruption on January 4, 2016, and solid and block form for eruption ash 6 February 2016 and October 3 2018. High crystallinity causes the Soputan magma to have sufficient viscosity for explosive eruptions. The explosive character of Mount Soputan is recorded in the morphology of its volcanic ash.Keywords: Brittle fragmentation; crystallinity index; explosive eruption; volcanic ash

The Clay Mineralogy of the Haldon Gravels

Clay Minerals ◽  
1973 ◽  
Vol 10 (2) ◽  
pp. 87-97 ◽  
Author(s):  
R. J. O. Hamblin
Keyword(s):  
Clay Mineral ◽  
Clay Mineralogy ◽  
Crystallinity Index ◽  
Peak Height ◽  
The Other ◽  
Low Grade ◽  
X Ray ◽  
High Crystallinity ◽  
The Matrix ◽  
Low Crystallinity

AbstractThe less than 10 μm and less than 3 μm fractions of the heterogenous Haldon Gravels have been examined by X-ray diffractometry. Kaolinite of high to low crystallinity is the dominant clay mineral, with variable amounts of illite (clay mica) ; quartz, a little feldspar and anatase also occur. The kaolinite has been ranked using the crystallinity index of Hinckley and also by indices derived from the ratio of peak height to background height for the 10 and 11 peaks.Clay from the matrix of the psaphitic members of the Buller's Hill Gravel contains intermediate grade kaolinite with a little illite, but clay bodies included in this formation contain only low grade kaolinite with a high, but variable proportion of illite. The Tower Wood Gravel contains two distinct populations; one is identical to that of the Buller's Hill Gravel, the other consists of high crystallinity kaolinite with a little illite. Head Gravel formed from the Buller's Hill Gravel by solifluction contains intermediate to low crystallinity kaolinite.

A synchrotron X-ray diffraction study of a small congruent LiNbO3 crystal: A compatible approach to powder diffraction

2001 ◽  
Vol 16 (2) ◽  
pp. 81-85 ◽  
Author(s):  
Barbara Etschmann ◽  
Nobuo Ishizawa
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Goodness Of Fit ◽  
Crystal Size ◽  
X Ray Diffraction ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Small Crystals ◽  
Powder Particles ◽  
Lithium Niobate Crystals

Single-crystal synchrotron X-ray diffraction (XRD) data were collected and refined for congruent lithium niobate crystals 8 and 6 μm in diameter, sizes that are comparable to the size of the powder particles used in powder diffraction. The motivation for using such small crystals is to minimize problems such as extinction, which decrease with crystal size. The R/wR factors were 0.011/0.014 and 0.019/0.018, for the 8 and 6 μm data, respectively, and the goodness of fit factors were 2.3(1) and 1.63(8), which compare favorably with values obtained from previous powder and single-crystal diffraction studies. Results from single-crystal XRD using crystals less than 10 μm in size may rival those obtained from powder diffraction.

scholarly journals Analisis Tipikal Erupsi Gunung Lokon Periode Erupsi 2012-2013 Berdasarkan Karakterisasi Mikrostruktur Abu Vulkanik

Jurnal MIPA ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Dolfi Paulus Padara
Keyword(s):  
Water Content ◽  
Volcanic Ash ◽  
Explosive Eruption ◽  
Microstructure Analysis ◽  
Plagioclase Crystal ◽  
Vulcanian Eruption ◽  
Magma Viscosity ◽  
Brittle Fragmentation ◽  
Magma Rheology

Gunung Lokon yang berada di lengan utara Sulawesi adalah salah satu gunung api paling aktif di Indonesia. Perilaku erupsinya telah dipelajari melalui analisis mikrostruktur abu vulkanik. Tujuan dari karakterisasi mikrostruktur adalah untuk mengestimasi nilai dari viskositas dan permeabilitas magma. Karakterisasi mikrostruktur menggunakan XRD, FTIR, SEM/EDS/XRF dan µCT. Abu vulkanik Lokon adalah mineral polimorf yang banyak mengandung kristal plagioklase. Abu Lokon mempunyai kandungan air 0,3 -0,6 % berat dan massa dasarnya terdiri dari partikel vesikular dan non vesikular. Viskositas dari magma Lokon adalah sekitar 107Pa.s pada 10000C dan fraksi volume kristal sekitar 0,45-0,5. Hasil-hasil ini menunjukkan bahwa reologi magma Lokon adalah bersifat non Newtonian dan mekanisme fragmentasinya adalah brittle fragmentation. Berdasarkan pada permeabilitas dan porositas yang dikuantisasi dengan µCT dapat disimpulkan bahwa fragmentasi magmanya tidak dipicu oleh outgassing. Dinamika erupsi eksplosif dari Gunung Lokon pada 2012-2013 adalah erupsi vulkanian pada skala sedang.Lokon volcano where located on North arm of Sulawesi is one of the most active volcanoes in Indonesia. Behaviour of its eruptions have been learned through microstructure analysis of volcanic ash. The goal of microstructure characterization is estimate value of magma viscosity and permeability. Characterization of microstructure using XRD, FTIR, SEM/EDS/XRF and µCT. Lokon volcanic ash is a polymorph minerals which contains many plagioclase crystal. Ash has water content between 0.3 – 0.6 % wt and its groundmass contains vesicular and non vesicular particles. Viscosity of Lokon magma is about 107Pa.s at 10000C and fraction of crystal volum between 0.45-0.5. These results showed that magma rheology of Lokon is non Newtonian and the mechanism of its fragmentation is brittle fragmentation. Based on permeability and porosity that quantified by µCT, it is concluded that the brittle fragmentation is not triggered by outgassing. Dynamics of explosive eruption of Lokon volcano at 2012-2013 is moderate vulcanian eruption.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

scholarly journals Study on the Electrical, Structural, Chemical and Optical Properties of PVD Ta(N) Films Deposited with Different N2 Flow Rates

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 937
Author(s):  
Yingying Hu ◽  
Md Rasadujjaman ◽  
Yanrong Wang ◽  
Jing Zhang ◽  
Jiang Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Crystal Size ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
Flow Rates ◽  
X Ray ◽  
N2 Flow Rate

By reactive DC magnetron sputtering from a pure Ta target onto silicon substrates, Ta(N) films were prepared with different N2 flow rates of 0, 12, 17, 25, 38, and 58 sccm. The effects of N2 flow rate on the electrical properties, crystal structure, elemental composition, and optical properties of Ta(N) were studied. These properties were characterized by the four-probe method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry (SE). Results show that the deposition rate decreases with an increase of N2 flows. Furthermore, as resistivity increases, the crystal size decreases, the crystal structure transitions from β-Ta to TaN(111), and finally becomes the N-rich phase Ta3N5(130, 040). Studying the optical properties, it is found that there are differences in the refractive index (n) and extinction coefficient (k) of Ta(N) with different thicknesses and different N2 flow rates, depending on the crystal size and crystal phase structure.

scholarly journals Valorization of Byproducts of Hemp Multipurpose Crop: Short Non-Aligned Bast Fibers as a Source of Nanocellulose

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4723
Author(s):  
Sara Dalle Vacche ◽  
Vijayaletchumy Karunakaran ◽  
Alessia Patrucco ◽  
Marina Zoccola ◽  
Loreleï Douard ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Cannabis Sativa ◽  
Crystallinity Index ◽  
Residual Lignin ◽  
Chemical Pretreatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bast Fibers ◽  
Seed Maturity

Nanocellulose was extracted from short bast fibers, from hemp (Cannabis sativa L.) plants harvested at seed maturity, non-retted, and mechanically decorticated in a defibering apparatus, giving non-aligned fibers. A chemical pretreatment with NaOH and HCl allowed the removal of most of the non-cellulosic components of the fibers. No bleaching was performed. The chemically pretreated fibers were then refined in a beater and treated with a cellulase enzyme, followed by mechanical defibrillation in an ultrafine friction grinder. The fibers were characterized by microscopy, infrared spectroscopy, thermogravimetric analysis and X-ray diffraction after each step of the process to understand the evolution of their morphology and composition. The obtained nanocellulose suspension was composed of short nanofibrils with widths of 5–12 nm, stacks of nanofibrils with widths of 20–200 nm, and some larger fibers. The crystallinity index was found to increase from 74% for the raw fibers to 80% for the nanocellulose. The nanocellulose retained a yellowish color, indicating the presence of some residual lignin. The properties of the nanopaper prepared with the hemp nanocellulose were similar to those of nanopapers prepared with wood pulp-derived rod-like nanofibrils.

scholarly journals Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Palash Sanphui ◽  
Geetha Bolla ◽  
Ashwini Nangia ◽  
Vladimir Chernyshev
Keyword(s):  
Hydrogen Bonds ◽  
Dissolution Rate ◽  
Aqueous Medium ◽  
Acid Amide ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Reference Drug ◽  
X Ray ◽  
Time Period ◽  
Solid Form

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR),p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.

Sorption and thermodynamic properties of juvenile Pinus sylvestris L. wood after 103 years of submersion

Holzforschung ◽  
2008 ◽  
Vol 62 (6) ◽  
Author(s):  
Luis García Esteban ◽  
Paloma de Palacios ◽  
Francisco García Fernández ◽  
Antonio Guindeo ◽  
Marta Conde ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Pinus Sylvestris ◽  
Integration Method ◽  
Juvenile Wood ◽  
Crystallinity Index ◽  
Isosteric Heat ◽  
Chemical Modifications ◽  
Clapeyron Equation ◽  
X Ray ◽  
Hemicellulose Degradation

Abstract The hygroscopicity and thermodynamic properties of juvenile Pinus sylvestris L. wood taken from the submerged piles of a bridge built in 1903 over the Jiloca River, in Spain, were compared with the corresponding values of juvenile wood of the same species from recently cut trees. The 35°C and 50°C isotherms were plotted and subsequently fitted using the Guggenheim-Anderson-Boer-Dent method, and the isosteric heat of sorption was obtained through the integration method of the Clausius-Clapeyron equation. The isotherms were compared by means of the hysteresis coefficients. Infrared spectra were recorded to study the chemical modifications, and the crystal structure of the cellulose was studied by X-ray diffractograms. The submersion in water resulted in hemicellulose degradation and a decrease in the crystallinity index and the crystallite length, accompanied by a corresponding increase in the proportion of amorphous zones. Owing to this, the equilibrium moisture contents of the water logged wood are higher than in the recent wood, both in adsorption and in desorption. In terms of the thermodynamic properties, the bond energy is higher in the recent wood than in the water logged wood.

Structural changes in titanium dioxide nanocrystals during plastic deformation

2005 ◽  
Vol 38 (5) ◽  
pp. 749-756 ◽  
Author(s):  
Ulrich Gesenhues
Keyword(s):  
Structural Changes ◽  
Crystal Size ◽  
Lower Layer ◽  
High Energy ◽  
Primary Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hall Method ◽  
Means Of Transmission

The polygonization of 200 nm rutile crystals during dry ball-milling at 10gwas monitored in detail by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The TEM results showed how to modify the Williamson–Hall method for a successful evaluation of crystal size and microstrain from XRD profiles. Macrostrain development was determined from the minute shift of the most intense reflection. In addition, changes in pycnometrical density were monitored. Accordingly, the primary crystal is disintegrated during milling into a mosaic of 12–35 nm pieces where the grain boundaries induce up to 1.2% microstrain in a lower layer of 6 nm thickness. Macrostrain in the interior of the crystals rises to 0.03%. The pycnometrical density, reflecting the packing density of atoms in the grain boundary, decreases steadily by 1.1%. The results bear relevance to our understanding of plastic flow and the mechanism of phase transitions of metal oxides during high-energy milling.

scholarly journals Novel solid forms of the analgesic drug ethenzamide

2014 ◽  
Vol 70 (a1) ◽  
pp. C995-C995
Author(s):  
Duane Choquesillo-Lazarte ◽  
Cristóbal Verdugo-Escamilla ◽  
Juan Manuel García-Ruiz
Keyword(s):  
Polycrystalline Material ◽  
X Ray Diffraction ◽  
Analgesic Drug ◽  
X Ray ◽  
Solution Methods ◽  
Additional Stability ◽  
Ft Ir ◽  
Model Drug ◽  
Solid Form ◽  
Ir And Raman

The interest in multicomponent solid forms has increased in the last years within the pharmaceutical industry and also the solid-state community due to the possibility of obtaining materials with new properties [1]. Crystallization strategies, supported by solvent- and solid-based techniques, have also received attention in the search and development of methodologies for the screening of multicomponent crystals. In this work, ethenzamide, an anti-inflammatory and analgesic drug, was selected as a model drug to develop cocrystals on the basis of the synthon types using a series of phenolic coformers. Ethenzamide cocrystals and cocrystal solvates have been reported recently [2,3]. Liquid Assisted Grinding (LAG) and solution methods were used as synthetic tools. Attempts to produce cocrystals by LAG and Reaction Crystallization led to the formation of polycrystalline material. The solids obtained were then characterized by powder X-ray diffraction (PXRD), FT-IR and Raman spectroscopy. Recrystallization by slow solvent evaporation was carried out when the above-referred techniques strongly suggest the formation of a new solid form. The structure of five new multicomponent solids has been determined by single crystal X-ray diffraction. Additional stability studies have been performed at controlled relative humidity conditions and followed by PXRD.

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