Characterization of Fly Ash and its Reactions in Concrete

1984 ◽  
Vol 43 ◽  
Author(s):  
Della M. Roy ◽  
Karen Luke ◽  
Sidney Diamond
Keyword(s):  
Particle Size ◽  
Low Rank ◽  
Chemical Dissolution ◽  
Fly Ashes ◽  
Characterization Methods ◽  
Distribution Shape ◽  
And Performance ◽  
Residual Coal

AbstractFly ashes are currently being produced that are much more widely different from each other in composition and other characteristics than had been previously experienced, owing to the widespread use of low rank subbituminous and lignitic coals. The current ASTM classifications into Class F and Class C pozzolan categories are not adequate to describe all their important properties. Current characterization methods are reviewed, including physical characterization by particle size distribution, shape, apparent specific gravity, content of hollow grains and of residual coal fragments, etc., chemical procedures of various kinds, and SEM, EDXA, XRD, and other methods for the determination of mineralogical content and glass character. Etching and chemical dissolution procedures are particularly important. The state of these various methods, current results of their use in rly ash characterizations, and the relations of these to reactivity and performance of fly ashes in cement and concrete are discussed.

Characterization of microneedles and microchannels for enhanced transdermal drug delivery

2021 ◽  
Author(s):  
Ashana Puri ◽  
Hiep X Nguyen ◽  
Akeemat O Tijani ◽  
Ajay K Banga
Keyword(s):  
Transdermal Delivery ◽  
Transdermal Drug Delivery ◽  
Review Paper ◽  
Low Molecular Weight ◽  
Kinetic Properties ◽  
Different Types ◽  
And Performance ◽  
Tools And Techniques

Microneedle (MN)-based technologies are currently one of the most innovative approaches that are being extensively investigated for transdermal delivery of low molecular weight drugs, biotherapeutic agents and vaccines. Extensive research reports, describing the fabrication and applications of different types of MNs, can be readily found in the literature. Effective characterization tools to evaluate the quality and performance of the MNs as well as for determination of the dimensional and kinetic properties of the microchannels created in the skin, are an essential and critical part of MN-based research. This review paper provides a comprehensive account of all such tools and techniques.

Extensions of Electron Diffraction Based Techniques in Crystallographic Characterization

2013 ◽  
Vol 753 ◽  
pp. 11-16
Author(s):  
Liang Zuo ◽  
Zong Bin Li ◽  
Yu Dong Zhang ◽  
Claude Esling ◽  
Xiang Zhao
Keyword(s):  
Electron Diffraction ◽  
Interface Plane ◽  
Data Input ◽  
Specific Level ◽  
Characterization Methods ◽  
Burgers Vector ◽  
Observation Plane ◽  
Dislocation Type

Abstract. With the advance of electron diffraction techniques in individual orientation analysis, traditional crystallographic characterization methods could be simplified, thus offering chances to develop some new approaches. In recent years, our group has devoted to working on possible extensions of the SEM and TEM based techniques for crystallographic analyses on a microstructure- and orientation-specific level. Several methods are illustrated in this paper, including the determination of dislocation type and Burgers vector without recourse to the traditional g.b invisibility condition, the identification of twinning mode and complete twinning elements for any crystal symmetry that requires minimum initial data input, and the characterization of specific interface plane or slip plane using only one sample observation plane instead of two perpendicular sample planes. These new extensions of characterization methods have proven to facilitate the related microstructural examinations.

Preparation and Characterization of Broad-Spectrum Sunscreens Loaded Nanostructured Lipid Carrier

2013 ◽  
Vol 669 ◽  
pp. 67-71
Author(s):  
Yan Ling Chen ◽  
Qiang Xia
Keyword(s):  
Particle Size ◽  
Physical State ◽  
Retention Rate ◽  
Nanostructured Lipid Carrier ◽  
High Pressure Homogenization ◽  
Spectrophotometric Detection ◽  
Ultraviolet Absorbance ◽  
Organic Uv Filters

A comprehensive photoprotective formulation was developed to enhance photoprotection ,compared to a conventional nanoemulsion ,having the concentration of two new molecular sunscreens, namely Diethylamino hydyoxybenzoyl hexyl benzoate(Uvinul ® A Plus) and Ethylhexyl triazone(Uvinul® T 150). In the present paper, the sunscreen mixture was incorporated into nanostructured lipid carriers (NLCs). After the production by hot high pressure homogenization, the NLC were analyzed in terms of particle size, physical state, particle shape, ultraviolet absorbance and stability. The particle size for all NLC was around 100-900 nm after production. The determination of 2 organic UV filters was performed by HPLC with UV spectrophotometric detection. The loading capacities for molecular sunscreens was up to 30%. In the sunlight, the retention rate of Uvinul ® A Plus and Uvinul ® T150 was still up to 80% after three months .

Characterization of solid magnetic nanoparticles by means of solid sampling high resolution continuum source electrothermal atomic absorption spectrometry

2016 ◽  
Vol 31 (12) ◽  
pp. 2391-2398 ◽  
Author(s):  
E. Vereda Alonso ◽  
M. M. López Guerrero ◽  
M. T. Siles Cordero ◽  
J. M. Cano Pavón ◽  
A. García de Torres
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Iron Concentration ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Direct Determination ◽  
Absorption Spectrometry ◽  
Solid Sampling ◽  
Continuum Source

Direct determination of iron concentration and particle size of solid MNPs using HR CS GFAAS.

scholarly journals Characterization of kaolin dispersion using acoustic and electroacoustic spectroscopy

2008 ◽  
Vol 44 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Z. Dohnalová ◽  
L. Svoboda ◽  
P. Sulcová
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Divalent Cations ◽  
Dispersing Agent ◽  
Time Period ◽  
Ultrasonic Techniques

The objective of this work is the investigation of the kaolin dispersion by the ultrasonic techniques. In contact with aqueous solution clay minerals show cation - exchange properties and certain degree of dissolution or rather selective leaching of components. The work is divided into two main parts - determination of zeta potential and particle size distribution. The first part is focused on measuring of zeta potential. Effects of concentration of solid, different kind of electrolytes (0.01 M KCl, 0.01 M MgCl2 and 0.01 M CaCl2), pH and temperature of the dispersions are investigated. The isoelectric points (IEP) of kaolin suspension are about pH 4-5. Electrolytes containing monovalent cations such as K+ become zeta potential more negative compared to the values obtained with water. Such behavior is explained by the exchange of K+ ions with H+ ions in the system. When the electrolyte is formed by divalent cations such as Mg2+ or Ca2+, the values of zeta potential become less negative than zeta potential of kaolin in water. The second part is focused on the determination of particle size distribution with respect to dispersing conditions, such as the optimal dispersing agent (Na2SiO3, (NaPO3)6, Na4P2O7 or Busperse), time and power of ultrasonication and also the tracking of dispersion stability that is expressed by the measuring of particle size distribution during certain time period.

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