scholarly journals Catalytic Action of Nitric Acid on The Hydrolysis of ETS-40 Ethyl Silicate

2021 ◽  
Vol 15 (4) ◽  
pp. 475-478
Author(s):  
Iryna Lutsyuk ◽  
◽  
Yaroslav Vakhula ◽  
Iryna Tupis ◽  
Iryna Iliuchok ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nitric Acid ◽  
Dispersion Analysis ◽  
Ethyl Silicate ◽  
Hydrolysis Rate ◽  
Maximum Temperature ◽  
Different Temperatures ◽  
Hydrolysis Of ◽  
Scanning Electron

The effect of concentrated nitric acid on the hydrolysis rate of ETS-40 ethyl silicate hasbeen studied. The duration and maximum temperature of ethyl silicate hydrolysis at different temperatures of the components have been determined. The formation of silica particles in the xerogel structure is shown. The influence of the ETS-40 hydrolysis on the particles size and concentration has been examined. The structure of the xerogel and the composition of the formed particles have been investigated using scanning electron microscopy (SEM) and energy dispersion analysis (EDX).

Poly (vinylcaprolactam)-based Microgels to Improve Gloss Properties of Different Natural Fibres

2014 ◽  
Vol 18 (1) ◽  
pp. 50-63 ◽  
Author(s):  
A.G. Hassabo ◽  
S. Schachschal ◽  
C. Cheng ◽  
A. Pich ◽  
C. Popescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Itaconic Acid ◽  
Natural Fibres ◽  
Different Temperatures ◽  
Scanning Electron

Three different thermo-sensitive microgels obtained by the copolymerisation of vinylcaprolactam) (VCL) and various monomers (vinylimidazole(VIm), acetoacetoxyethyl methacrylate (AAEM) and itaconic acid(IA)) are used to coat different fibre surfaces. Two different pHs and two different temperatures, 25°C and 50°C respectively are chosen for the deposition of the microgels. The scanning electron microscopy of the treated fibre shows good distribution of the particles onto the fibres especially at increasing temperatures. The gloss index for the treated fibres has been measured, and showed that it may be controlled for all of the fibres with the treatment parameters (pH and temperature) and the microgel structure.

Morphology of Sintered Cr-Mo Porous Materials

2015 ◽  
Vol 825-826 ◽  
pp. 838-843
Author(s):  
Moritz Boehm ◽  
Thomas Schmoelzer ◽  
Reinhard Simon ◽  
Christian Gierl-Mayer
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Linear Expansion ◽  
Solid Phase ◽  
Phase Region ◽  
Miscibility Gap ◽  
Liquidus Boundary ◽  
Different Temperatures ◽  
Scanning Electron

Chromium and molybdenum exhibit continuous solubility in the solid phase region at temperatures of 908°C and above [1]. At lower temperatures, the system exhibits a miscibility gap. Furthermore a congruent minimum in the liquidus boundary exists at 1854°C. Chromium and molybdenum powders with different particle morphologies were mixed and porous green parts were produced by pressing. Sintering experiments were performed at different temperatures and for different chromium to molybdenum ratios. To investigate the evolution of the microstructure, sintering was interrupted at different temperatures and points in time. The microstructure and morphology of the sintered parts was investigated by scanning electron microscopy as well as light optical microscopy. It was found that during sintering, a Cr-Mo solid solution is formed. Depending on the molybdenum content, this induces either shrinking or swelling of the porous parts. Samples exhibited a linear expansion of up to 10% and final porosities of up to 65%.

scholarly journals Effect of metal ions and surfactants on the enzymatic hydrolysis of pretreated lignocellulose

BioResources ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 1653-1667
Author(s):  
Yawen Zhou ◽  
Jian Yang ◽  
Cong Luo ◽  
Bo Yang ◽  
Changyao Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Enzymatic Hydrolysis ◽  
Infrared Spectrum ◽  
Metal Ions ◽  
Spectrum Analysis ◽  
Tween 80 ◽  
High Porosity ◽  
Hydrolysis Of ◽  
Scanning Electron

The effect of metal ions and surfactants on the enzymatic hydrolysis of pretreated wheat straw lignocellulose was investigated. Scanning electron microscopy, infrared spectrum analysis, dynamic light scattering, and fluorescence spectra analysis were used to characterize the influence of Fe3+/ polyoxyethylene (20) sorbitan monooleate (Tween 80). The interaction between Fe3+/Tween 80 and enzyme was further investigated by enzyme kinetics and enzyme activity measurements. The best synergistic effect was obtained when the ratio of Fe3+ and Tween 80 was 0.06. The scanning electron microscopy images showed that the Fe3+/Tween 80 combination was associated with high porosity substrates. The infrared spectrum analysis indicated that the components of the substrates depended on additive types. The highest relative enzymatic activity increase rate was obtained with added Fe3+/ Tween 80. The Vmax and Km values of the group with added Fe3+/Tween 80 were much higher than that of the group without additives. With the addition of Fe3+/ Tween 80, the intensity of the fluorescence emission peak decreased and the peak shifted towards a longer wavelength.

Study of the Influence of Temperature on the Optical and Structural Properties of Dolomite

2020 ◽  
Vol 74 (10) ◽  
pp. 1280-1286
Author(s):  
Lucas Train Loureço ◽  
Celso de Araujo Duarte ◽  
Dietmar William Foryta ◽  
Bruno Guimarães Titon ◽  
Eleonora Maria Gouvêa Vasconcellos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Treatment ◽  
X Ray Diffraction ◽  
Electron Dispersive Spectroscopy ◽  
Influence Of Temperature ◽  
X Ray ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The present work reports the results of structural and optical investigations in samples of natural dolomite, subjected to thermal treatment at different temperatures (500 ℃ to 700 ℃) and times (one up to three hours). The motivation is the evaluation of the changes that may occur in carbonaceous asteroids and meteorites, respectively, subjected to the action of the solar radiation and heated during the fall in the atmosphere. We carried out scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, optical reflectance and photoluminescence measurements

Microwave Synthesis of BaTiO3 from BaCO3 and TiO2

2007 ◽  
Vol 336-338 ◽  
pp. 669-671
Author(s):  
Yan Yi Liu ◽  
Wei Pan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Microwave Oven ◽  
X Ray Diffraction ◽  
X Ray ◽  
Batio3 Powder ◽  
Domestic Microwave Oven ◽  
Intermediate Phases ◽  
Different Temperatures ◽  
Scanning Electron

BaTiO3 powder was synthesized from BaCO3 and TiO2 using a domestic microwave oven. The samples were synthesized under different temperatures with various holding times. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to examine the phase compositions and morphologies of the result samples. The main phase obtained at 950°C was BaTiO3, and the intermediate phases Ba2TiO4 and Ba4TiO9 were also detected. The pure, well-crystallized BaTiO3 powder could be obtained at 1050°C within 10 minutes and the particle size ranged from 300~500nm. In comparison with conventional synthesis, faster speed and finer grains could be achieved through microwave heating.

scholarly journals Structure and microstructure of coronary dentin in non-erupted human deciduous incisor teeth

2002 ◽  
Vol 13 (3) ◽  
pp. 170-174 ◽  
Author(s):  
Luciane R.R S. Costa ◽  
Ii-Sei Watanabe ◽  
Márcia C. Kronka ◽  
Marcelo C.P. Silva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nitric Acid ◽  
Light Microscopy ◽  
Three Dimensional ◽  
Dentinal Tubules ◽  
Sem Study ◽  
Structure And Microstructure ◽  
Hematoxylin Eosin ◽  
Scanning Electron

The dentin structure of non-erupted human deciduous mandibular and maxillary central and lateral incisor teeth was studied employing light and scanning electron microscopy. For light microscopy, nitric-acid-demineralized and ground sections were used. The sections were stained by hematoxylin-eosin, picrosirius and azo-carmim methods, and ground specimens were prepared using a carborundum disk mounted in a handpiece. For SEM study, teeth were frozen in liquid nitrogen and fractured at longitudinal and transversal directions. Structurally, demineralization and ground methods revealed tubules with primary and secondary curvatures, canaliculi, giant tubules, interglobular dentin, predentin, and intertubular dentin. Scanning electron microscopy showed three-dimensional aspects of dentinal tubules, canaliculi, peritubular dentin, intertubular dentin, and predentin. This study contributes to knowledge about dentin morphology showing characteristics of teeth not yet submitted to mastication stress.

Laminate Orientation and Thickness Effects on An Scs-6/Ti-24ai-11 Nb Composite Under Thermal Fatigue

1992 ◽  
Vol 273 ◽  
Author(s):  
William C. Revelos ◽  
Itzhak Roman
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Acoustic Emission ◽  
Thermal Fatigue ◽  
Room Temperature ◽  
Maximum Temperature ◽  
Composite Strength ◽  
Inert Environment ◽  
Tension Tests ◽  
Scanning Electron

ABSTRACTA SiC/Ti-24AI-11 Nb (at. %) composite (30–35 vol. %) was thermally cycled in air and an inert environment between 150 °C and 815 °C for various cycle counts. Various hold times at maximum temperature were employed to determine timedependent effects on composite integrity. Laminate orientations investigated included: [0]4, [0]8, [90]4, [90]8 and [0/90]2S. Acoustic emission produced during thermal fatigue of selected specimens was employed to monitor damage progression. Post-cycling room temperature tension tests as well as optical and scanning electron microscopy were used to document damage, which was particularly acute when hold times at temperature were employed on tests performed in air. The roles of the environment, composite thickness, and off-axis fibers during thermal fatigue on the composite strength and integrity are discussed.

An Experimental Approach for Studying Chalcopyrite Leaching and Passivation in Column Bioleaching

2009 ◽  
Vol 71-73 ◽  
pp. 381-384
Author(s):  
Tuomas van der Meer ◽  
Jussi Liipo ◽  
Jaakko Leppinen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Analysis ◽  
Experimental Approach ◽  
Microbial Consortia ◽  
Heap Bioleaching ◽  
Different Temperatures ◽  
Leaching Solution ◽  
Continuous Potential ◽  
Scanning Electron

The effect of different microbial consortia on the leaching of chalcopyrite was studied at different temperatures and solution compositions with Boliden’s Aitik ore in column reactors simulating heap bioleaching. The columns were equipped with sampling chambers and chalcopyrite mineral electrodes in order to investigate the passivation of chalcopyrite. The sampling chambers were filled with agglomerated ore and pieces of chalcopyrite-rich ore. In addition to chemical analysis of the leaching solution and solids the progress of leaching of chalcopyrite was studied by continuous potential measurements with chalcopyrite electrodes. The occurrence and composition of potentially passivating layers on the surfaces of the electrodes and the samples taken from sample chambers were examined by optical and scanning electron microscopy.

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