scholarly journals Selective Crystallization of Silicoalumophosphate Sapo-11 With A Micromesoporous Structure

2021 ◽  
Vol 9 (2) ◽  
pp. 109-111
Author(s):  
Zulfiya Khayrullina ◽  
Kanaan R. Ahmed ◽  
Samara Kambarova ◽  
Marat Agliullin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Molecular Sieve ◽  
Mesoporous Structure ◽  
Selective Crystallization ◽  
Scanning Electron

ABSTRACT:The authors have proposed a method for the selective crystallization of a SAPO-11 silicoaluminophosphate molecular sieve with a micro-mesoporous structure. It has been shown that crystallization of a silicoaluminophosphate gel, in the preparation of which its isopropoxide is used as a source of aluminum, makes it possible to obtain a SAPO-11 molecular sieve with a specific surface area of ​​~ 207 m2 / g, a volume of micro- and mesopores of ~ 0.08 and 0.09 cm3 / g. , respectively. Using scanning electron microscopy, it was demonstrated that the crystals of the material are pseudospherical particles ~ 8-10 microns in size, consisting of aggregates of nanocrystals ~ 100-200 nm in size.

Specific Surface Area of Snow Samples Determined by CH4Adsorption at 77 K and Estimated by Optical Microscopy and Scanning Electron Microscopy

2001 ◽  
Vol 35 (4) ◽  
pp. 771-780 ◽  
Author(s):  
Florent Dominé ◽  
Axel Cabanes ◽  
Anne-Sophie Taillandier ◽  
LoÏc Legagneux
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Optical Microscopy ◽  
Surface Area ◽  
Specific Surface Area ◽  
Scanning Electron ◽  
Snow Samples

scholarly journals Nanomaterial identification of powders: comparing volume specific surface area, X-ray diffraction and scanning electron microscopy methods

2019 ◽  
Vol 6 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Claire Dazon ◽  
Olivier Witschger ◽  
Sébastien Bau ◽  
Vanessa Fierro ◽  
Philip L. Llewellyn
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
X Ray Diffraction ◽  
Reliable Criterion ◽  
X Ray ◽  
Area X ◽  
Scanning Electron

This work shows that the volume specific surface area could be a reliable criterion for nanomaterial identification.

Rate of decay of specific surface area of snow during isothermal experiments and morphological changes studied by scanning electron microscopy

2003 ◽  
Vol 81 (1-2) ◽  
pp. 459-468 ◽  
Author(s):  
L Legagneux ◽  
T Lauzier ◽  
F Domin ◽  
W F Kuhs ◽  
T Heinrichs ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Decay Rate ◽  
Surface Area ◽  
Specific Surface Area ◽  
Morphological Changes ◽  
Main Process ◽  
Snow Crystals ◽  
Scanning Electron

The quantification of the specific surface area (SSA) of snow crystals and of its variation during metamorphism are essential to understand and model the exchange of reactive gases between the snowpack and the atmosphere. Therefore, the decay rate of SSA of five fresh snow samples was studied in the laboratory at –4, –10, and –15°C under isothermal conditions in closed systems. The time-evolution of the snow SSA can in all cases be very well described by an empirical law of the form, SSA = – A log(t + Δt) + B, where A, B, and Δt are adjustable parameters. B seems to be closely related to the initial SSA of the snow, and A describes the SSA decay rate. Our preliminary findings at –15°C suggest that a linear relationship exists between A and B, so that it may be possible to predict the decay rate of snow SSA from its initial value. For the first time, images obtained from scanning electron microscopy show that crystal rounding of snow is the main process taking place during isothermal metamorphism. New grain boundaries also form. More surprising, however, was the formation of new basal, prismatic, and pyramidal crystal faces, sometimes with very sharp angles, especially at –15°C. The growth of facets with sharp angles is not fully explained by current theories of snow metamorphism and has not been observed before. PACS Nos.: 68.35Md, 68.37Hk, 81.20Ev, 81.05Rm

Structural and morphological features of MgO powders. The key role of the preparative starting compound

1998 ◽  
Vol 13 (8) ◽  
pp. 2218-2223 ◽  
Author(s):  
S. Ardizzone ◽  
C. L. Bianchi ◽  
B. Vercelli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Starting Compound ◽  
Scanning Electron

The present paper reports data concerning magnesia samples obtained by calcination of different precursor salts at different increasing temperatures (873–1253 K). The oxides are characterized by x- ray diffraction, scanning electron microscopy, and N2 adsorption at subcritical temperatures. The samples appear to be composed, at any temperature, of pure periclase with a degree of crystallinity which increases with the temperature of calcination. Morphologically, the products have the shape either of lamellas or of cubes of variable dimensions, depending on the nature and route of preparation of the precursor salts. The variation of the specific surface area and the degree of porosity with the nature of the precursors and the temperature is discussed.

Effects of dry grinding on pyrophyllite

Clay Minerals ◽  
1988 ◽  
Vol 23 (4) ◽  
pp. 399-410 ◽  
Author(s):  
J. L. Pérez-Rodríguez ◽  
L. Madrid Sánchez del Villar ◽  
P.J. Sánchez-Soto
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Grinding Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Grinding ◽  
Scanning Electron ◽  
Area Data

AbstractDry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ∼60 m2·g−1. Marked changes in the structure take place between 30 and 32 mins grinding. Longer grinding times increase the degree of disorder and SEM and specific surface area data suggest that aggregation occurs. XRD results indicate that some residual order persists in the degraded structure.

scholarly journals Influence of mechanical activation on synthesis of zinc metatitanate

2005 ◽  
Vol 37 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Nebojsa Labus ◽  
Nina Obradovic ◽  
Tatjana Sreckovic ◽  
V. Mitic ◽  
Momcilo Ristic
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Specific Surface ◽  
Mechanical Activation ◽  
Surface Area ◽  
Perovskite Structure ◽  
Mechanical Treatment ◽  
X Ray ◽  
Scanning Electron

Investigations of a ZnO-TiO2 binary oxide mixture during mechanical treatment were mainly focused on obtaining orthotitanate Zn2TiO4 with a spinel structure. Due to the specific way of energy transfer during mechanical treatment using a high-energy ball mill, the system passes through low temperature ZnTiO3 metatitanate phase formation. Mechanical activation was performed on an equimolar ratio mixture of ZnO and TiO2. The anatase phase was previously submitted to heat treatment for achieving a starting mixture rich in a rutile phase. Milling conditions were preset for observing the formation of a low temperature ZnTiO3 phase with a perovskite structure. The powder microstructure was characterized using scanning electron microscopy. A nitrogen gas sorption analyzer with the BET method was used to determine the specific surface area and porosity, indicating changes of powder sample properties during mechanical activation. Also, X ray powder diffractometry was applied to obtain the phase composition. Powders were then pressed into pellets and their compressibility was observed through density changes. According to microstructures obtained by scanning electron microscopy analysis, the system underwent a primary and secondary agglomeration process. Specific surface area measurements supported that conclusion. Compressibility investigations established the difference between compressibility of the non-activated mixture and activated powders. X-ray diffraction analysis revealed that a perovskite structure forms simultaneously with a spinel phase during the process of mechanical activation.

Distribution of diaphragmatic lymphatic stomata

1991 ◽  
Vol 70 (4) ◽  
pp. 1544-1549 ◽  
Author(s):  
D. Negrini ◽  
S. Mukenge ◽  
M. Del Fabbro ◽  
C. Gonano ◽  
G. Miserocchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Frequency Distribution ◽  
Maximum Diameter ◽  
Minimum Diameter ◽  
Average Value ◽  
Scanning Electron

In seven anesthetized rabbits we measured the size, shape, and density of lymphatic stomata on the peritoneal and pleural sides of the diaphragm. The diaphragm was fixed in situ and processed for scanning electron microscopy. Results are from 2,902 peritoneal and 3,086 pleural fields (each 1,620 microns 2) randomly chosen from the various specimens. Stomata were seen in 9% of the fields examined, and in 30% of the cases they appeared grouped in clusters with 2-14 stomata/field. Stoma density was 250 +/- 242 and 72 +/- 57 (SD) stomata/mm2 on peritoneal and pleural sides, respectively, and it was similar over the muscular and tendinous portion of the two surfaces. The maximum diameter ranged from less than 1 to approximately 30 microns, with an average value of 1.2 +/- 3.1 micron. The ratio of the maximum to the minimum diameter and the surface area averaged 2 +/- 1.4 and 0.7 +/- 2.4 micron 2, respectively. The maximum and minimum diameter and surface area values followed a lognormal frequency distribution, suggesting that stomata geometry is affected by diaphragmatic tension.

Characterization of Pacemaker Electrode Surfaces Utilizing Scanning Electron Microscopy (SEM) and In-Vitro Electrochemical Analysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 402-403
Author(s):  
Scott Brabec ◽  
Bill Schindeldecker ◽  
Ken Brennen ◽  
Sue Okerstrom ◽  
Ky Pham
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Impedance Spectrum ◽  
Sample Surface ◽  
Electrochemical Analysis ◽  
Platinum Black ◽  
Conductive Surface ◽  
Scanning Electron

The efficiency of implantable electrodes for cardiac pacing depends on the ratio of the conductive surface area to the geometric area of the interface with excitable tissue. New models of heart pacers require reduction of post-pulse polarization, i.e. the potential left on the electrode / tissue interface after a pacemaker pulse. Increasing the conductive surface area is an effective method to this end. Microscopy provides an important tool in elucidating the role of surface structure in electrode performance.Three different surface textures were characterized on a 90% platinum(Pt)/10% iridium (Ir) polished electrode substrate of roughly 5 mm2 geometric surface area. These consisted of the polished substrate itself, a thin film of textured platinum in the 1-3 micron size range, and a sub-micron platinum black coating. Sample surface effects were characterized via scanning electron microscopy (SEM), in-vitro electrical impedance spectrum analysis, and polarization after-potential measurements.

scholarly journals Kesetimbangan Adsorpsi Zat Warna Methyl Violet Oleh Karbon Aktif Berbasis Limbah Daun Nanas (Ananas comosus L)

METANA ◽  
2018 ◽  
Vol 14 (2) ◽  
pp. 31
Author(s):  
Lanjar Lanjar ◽  
Fatma Indah Riayanti ◽  
Widi Astuti
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Surface Area ◽  
Methyl Violet ◽  
Fourier Transform Infrared ◽  
Ananas Comosus ◽  
Ftir Spectrometer ◽  
Model Isotherm ◽  
Scanning Electron

Industri tekstil semakin berkembang seiring dengan pertumbuhan penduduk di Indonesia. Selain memberikan manfaat, industri tekstil  memberikan dampak negatif bagi lingkungan akibat penggunaan zat warna sintetis, salah satunya yaitu methyl violet. Apabila limbah tersebut dibuang ke perairan akan menyebabkan rusaknya ekologi lingkungan dan ancaman bagi kesehatan manusia, karena sebagian besar zat warna bersifat sukar terurai (non-bidegradable) dan karsinogenik (Brono, 2010). Salah satu metode yang terbukti efektif untuk menghilangkan zat warna adalah adsorpsi menggunakan karbon aktif. Pada penelitian ini karbon aktif dibuat dari limbah daun nanas dengan aktivator ZnCl2 dan pemanasan gelombang mikro. Selanjutnya, karbon aktif tersebut dikarakteriasi morfologi permukaan menggunakan Scanning Electron Microscopy (SEM), luas permukaan menggunakan Surface Area Analyzer, dan analisis gugus fungsi menggunakan Fourier Transform Infrared (FTIR) spectrometer, dan digunakan untuk menjerap methyl violet di larutan. Hasil penelitian menunjukkan bahwa karbon aktif dari limbah daun nanas yang teraktivasi ZnCl2 menghasilkan pori yang lebih besar dibandingkan dengan karbon tanpa aktivasi serta memiliki gugus fungsi yang dapat menjerap methyl violet. Kondisi optimum untuk adsorpsi adalah pH 5, waktu kontak 90 menit, dan konsentrasi awal 500 mg/L. Model kesetimbangan yang sesuai yaitu menggunakan model isotherm freundlich.

Scanning electron microscopy and surface area studies of calcined ZnCrCl layered doubled hydroxides

1995 ◽  
Vol 14 (24) ◽  
pp. 1747-1750 ◽  
Author(s):  
M. Zobir Hussein ◽  
Z. Zainal ◽  
H. H. Swee
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Area ◽  
Area Studies ◽  
Scanning Electron
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