Sources of Self-Hardening Properties in Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
R. C. Joshi ◽  
D. T. Lam
Keyword(s):  
Fly Ash ◽  
Thermal Analyses ◽  
Electron Microscopic Examination ◽  
Water Soluble ◽  
The Self ◽  
Reaction Products ◽  
Fly Ashes ◽  
Electron Microscopic ◽  
Physical Tests ◽  
Physical And Chemical

Laboratory investigations of the self-hardening properties of selected subbituminous fly ashes have been conducted. Chemical analyses of the fly ashes are given in Table I. The self-hardening value of the fly ashes was determined by conducting unconfined compressive strength tests on compacted samples of the moistened ashes. Various physical and chemical tests were performed to identify the reaction products, if any, of the hardened compacted fly ash paste, and to delineate the source of self-hardening properties. Results from x-ray diffraction analyses, scanning electron microscopic examination and differential thermal analyses indicated that the hydration products include calcium silicate and aluminate hydrates, and ettringite. Chemical and physical tests conducted to evaluate pertinent fly ash properties included chemical analysis, water soluble fraction, dilute hydrochloric and hydrofluoric acid soluble fractions, heat of solution on dissolving in dilute hydrochloric acid, specific surface area, and electrical conductivity tests.

Some Physical, Chemical and Mineralogical Properties of Some Canadian Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
R. C. Joshi ◽  
B. K. Marsh
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Water Soluble ◽  
Pozzolanic Activity ◽  
Unburned Carbon ◽  
Magnetic Fraction ◽  
Fly Ashes ◽  
Physical And Chemical

ABSTRACTThis paper gives physical and chemical properties of some Canadian fly ashes. Specific surface area, magnetic fraction, water soluble fraction and fraction finer than 45 μm were determined as part of the physical tests. Thermo-gravimetric analyses (TGA) in oxygen and nitrogen were conducted on raw ash samples. The change of pH with time in suspensions of the different ashes in water was also determined. Pozzolanic activity of the ashes with lime for all the ashes was evaluated to measure ash reactivity.The ash activity seems to be related to fineness of the ash measured by the Blaine air permeability method, but not to the fineness measured by nitrogen sorption. Generally the greater the specific surface area, the higher the reactivity of the ash. The correlation was, however, not strong and no other physical or chemical parameter measured in this investigation seems to be related to pozzolanic activity.The results of pH and TGA tests indicated that the ashes differ in many respects from each other. The TGA data suggest that loss on-ignition in many of the ashes is not entirely due to the presence of unburned carbon. Specific surface area determined by various methods seems to provide different values. No characterization parameter was found that was uniquely related to coal type.

Influence of Physical and Chemical Properties on the Activity of Fly Ashes

1987 ◽  
Vol 113 ◽  
Author(s):  
F. Sybertz
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Hydrochloric Acid ◽  
Potassium Hydroxide ◽  
Chemical Properties ◽  
Experimental Program ◽  
Physical And Chemical Properties ◽  
Fly Ashes ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTIn an experimental program, the suitability of various methods for testing the pozzolanic activity of fly ash was investigated. The research was conducted on virtually all fly ashes approved as concrete additives in Germany. This paper discusses differences in the particle size distribution and the solubility on dissolution with hydrochloric acid and potassium hydroxide of the fly ashes. It also reports on interrelationships between the physical and chemical properties of the fly ashes and the workability and strength of mortars containing fly ash.

Production and Characterization of Fly Ash from New South Wales Coals

1985 ◽  
Vol 65 ◽  
Author(s):  
Harold Roper ◽  
Daksh Baweja ◽  
Graham A. Kirkby
Keyword(s):  
Fly Ash ◽  
New South ◽  
New South Wales ◽  
Mineral Admixture ◽  
Chemical Characteristics ◽  
Fly Ashes ◽  
Boiler Furnace ◽  
Factors Affecting ◽  
South Wales ◽  
Physical And Chemical

ABSTRACTFactors affecting fly ash characteristics are examined by consideration of the various processes and constituents involved in its production. Coal conversion, boiler-furnace operations and collection procedures are discussed. Current classification schemes applied to fly ash, in particular to those for use as a pozzolanic mineral admixture in concrete are reviewed. The variability of the material is highlighted using physical and chemical data. Shape and size characteristics of selected fly ashes from sources within New South Wales, Australia are illustrated by electron micrographs. The influence of these properties on resultant concrete properties are briefly considered. The formation of nodules of fly ash material on the surface of fabric filters is chosen to illustrate the importance of physical and chemical conditions in the collection chamber, whereas pH changes with time of the water phase in contact with selected fly ashes demonstrate the importance of chemical characteristics of the collected materials. Such chemical characteristics may influence the path of pozzolanic reactions significantly.

scholarly journals Boron contents and solubility in Australian fly ashes and its uptake by canola (Brassica napus L.) from the ash-amended soils

Soil Research ◽  
2010 ◽  
Vol 48 (5) ◽  
pp. 480 ◽  
Author(s):  
V. Manoharan ◽  
I. A. M. Yunusa ◽  
P. Loganathan ◽  
R. Lawrie ◽  
B. R. Murray ◽  
...  
Keyword(s):  
Fly Ash ◽  
Boron Concentration ◽  
Coal Fly Ash ◽  
Water Soluble ◽  
Hot Water ◽  
Acidic Soils ◽  
Fly Ashes ◽  
Brassica Napus L ◽  
Pot Trials ◽  
B Uptake

Phytotoxicity due to excessive boron (B) uptake by plants impedes routine agronomic utilisation of coal fly ash. We assessed 11 fly ashes (pH 3.14–10.77) having total B content (Bt) of 12–136 mg/kg, of which 20–30% was hot water soluble (Bs) in the acidic ashes (pH <5) and 5–10% in the alkaline ashes, for their potential to supply B to plants and their risk associated with phytotoxicity. We found the Bs/Bt to be negatively correlated (R2 = 0.63**, N = 11) with ash pH. We conducted two pot trials in which canola was grown in soils amended with fly ash. In the first trial, an alkaline fly ash (Bt 66 mg/kg) was incorporated at 5 rates of up to 625 Mg/ha into the top 50 mm of 2 acidic soils in 0.30-m-long intact cores, and sown with canola. Boron concentration in leaves at flowering reached the phytotoxic threshold, and both plant growth and seed yield were reduced, only at 625 Mg/ha. In the second trial, 4 fly ashes (pH 3.29–10.77, Bt 12–127 mg/kg) were incorporated at 4 rates of up to 108 Mg/ha into the top 0.10 m of 2 acidic soils in 1.0-m-long intact cores and then sown with canola. Ashes with highest Bt, when applied at 108 Mg/ha, increased B concentration in the topsoil only. Of the 2 ashes with the highest Bt, only that which produced low soil pH and applied at 108 Mg/ha increased B concentration in the shoot, but was still below phytotoxic threshold. The results suggest that B derived from these ashes may not cause phytotoxicity and excessive soil B accumulation if the ashes are applied at modest rates (<36 Mg/ha) to the topsoil layers.

scholarly journals Immunohistochemical demonstration of Fc receptors of human lymph node cells using peroxidase-antiperoxidase (IgG).

1980 ◽  
Vol 28 (3) ◽  
pp. 271-275 ◽  
Author(s):  
G Itoh
Keyword(s):  
Lymph Node ◽  
Cell Surface ◽  
Microscopic Examination ◽  
Fc Receptors ◽  
Electron Microscopic Examination ◽  
Reaction Products ◽  
Electron Microscopic ◽  
Regional Lymph Nodes ◽  
Human Lymph Node ◽  
Lymph Node Cells

Human lymph node cells, prepared from regional lymph nodes excised from four patients with gastric cancer, were incubated with peroxidase-antiperoxidase (IgG) (PAPIgG). After being washed, they were reacted with diaminobenzidine tetrahydrochloride in the presence of H2O2. Light microscopic examination revealed that a certain proportion of lymph node cells (18.2-32.2%) were labeled on their cell surface with brown-colored reaction products and that the labeled cells were composed of small lymphocytes. Electron microscopic examination demonstrated electron-dense irregular-shaped aggregates of reaction products on the cell surface of lymphocytes. Characterization experiments confirmed that the immune complexes of PAPIgG bound specifically with Fc receptors. PAPIgG, therefore, can be used as a specific indicator for Fc receptor of human lymph node cells.

Variability and Trends in Iowa Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plant ◽  
Coefficient Of Variation ◽  
Power Plants ◽  
Chemical Properties ◽  
Physical Analysis ◽  
Fly Ashes ◽  
High Calcium ◽  
Physical And Chemical

ABSTRACTAn investigation has been made of the variability of physical and chemical properties of high-calcium (Class C) fly ashes from four Iowa power plants. The investigation summarizes results obtained from three years (1983 through 1985) of monitoring of the various power plants. All four of the power plants burn low-sulfur, sub-bituminous coal from Wyoming. Fly ash samples were obtained from the power plants in accordance to the procedures described in ASTM C 311. Laboratory testing methods were similar to those specified by ASTM C 311. During the three year period, 102 samples were subjected to chemical and physical analysis while an additional 349 samples were subjected to physical analysis only. In general, the four power plants produce fly ashes of similar mineralogy and chemical composition. The observed time variation of the chemical composition of fly ash from a single power plant was quite small. The sulfur content consistently showed the largest coefficient of variation of the 10 elements studied. Physical characteristics of the fly ashes (as measured by ASTM tests) were also fairly uniform over long periods of time, when considered on an individual power plant basis. Fineness, when measured by wet washing using a 325 mesh sieve, consistently exhibited the largest coefficient of variation of any of the physical properties studied.

Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

1978 ◽  
Vol 36 (2) ◽  
pp. 46-47
Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder
Keyword(s):  
Mammary Gland ◽  
Protein Denaturation ◽  
Chemical Constituents ◽  
Freeze Substitution ◽  
Electron Microscopic Examination ◽  
Mouse Mammary Gland ◽  
Electron Microscopic ◽  
Preparation Methods ◽  
Microscopic Studies ◽  
Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

A Comparative Study of Fractographic Replicas

1974 ◽  
Vol 32 ◽  
pp. 566-567
Author(s):  
Loren Anderson ◽  
Pat Pizzo ◽  
Glen Haydon
Keyword(s):  
Electron Microscopy ◽  
Electron Microscopic Examination ◽  
Direct Examination ◽  
Electron Microscopic ◽  
Reliable Technique ◽  
Service Failures ◽  
Transmission Electron ◽  
Mode Of Failure ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Transmission electron microscopy of replicas has long been used to study the fracture surfaces of components which fail in service. Recently, the scanning electron microscope (SEM) has gained popularity because it allows direct examination of the fracture surface. However, the somewhat lower resolution of the SEM coupled with a restriction on the sample size has served to limit the use of this instrument in investigating in-service failures. It is the intent of this paper to show that scanning electron microscopic examination of conventional negative replicas can be a convenient and reliable technique for determining mode of failure.

Novel methods for demonstrating osseointegration of hydroxylapatite-coated titanium hip prostheses

1991 ◽  
Vol 49 ◽  
pp. 34-35 ◽  
Author(s):  
P. Frayssinet ◽  
J. Hanker ◽  
D. Hardy ◽  
B. Giammara
Keyword(s):  
Hip Prosthesis ◽  
Ethanol Concentration ◽  
Bone Matrix ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Hip Prostheses ◽  
Cellular Inclusions ◽  
Microscopic Studies ◽  
Diamond Saw ◽  
Plasma Sprayed

Prostheses implanted in hard tissues cannot be processed for electron microscopic examination or microanalysis in the same way as those in other tissues. For these reasons, we have developed methods allowing light and electron microscopic studies as well as microanalysis of the interface between bone and a metal biomaterial coated by plasma-sprayed hydroxylapatite(HA) ceramic.An HA-coated titanium hip prosthesis (Corail, Landos, France), which had been implanted for two years, was removed after death (unrelated to the orthopaedic problem). After fixation it was dehydrated in solutions of increasing ethanol concentration prior to embedment in polymethylmethacrylate(PMMA). Transverse femur sections were obtained with a diamond saw and the sections then carefully ground to a thickness of 200 microns. Plastic-embedded sections were stained for calcium with a silver methenamine modification of the von Kossa method for calcium staining and coated by carbon. They have been examined by back-scatter SEM on an ISI-SS60 operated at 25 KV. EDAX has been done on cellular inclusions and extracellular bone matrix.

Properties of Isolated Mitochondria of Agaricus Bisporus: Their Relationship to Dormancy and the Germination of Spores

1973 ◽  
Vol 31 ◽  
pp. 458-459
Author(s):  
K. S. McCarty ◽  
R. F. Weave ◽  
L. Kemper ◽  
F. S. Vogel
Keyword(s):  
Mitochondrial Dna ◽  
Ethidium Bromide ◽  
Microscopic Examination ◽  
Agaricus Bisporus ◽  
Osmotic Shock ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Isolated Mitochondria ◽  
Dna Strands ◽  
Cytoplasmic Ribosomes

During the prodromal stages of sporulation in the Basidiomycete, Agaricus bisporus, mitochondria accumulate in the basidial cells, zygotes, in the gill tissues prior to entry of these mitochondria, together with two haploid nuclei and cytoplasmic ribosomes, into the exospores. The mitochondria contain prominent loci of DNA [Fig. 1]. A modified Kleinschmidt spread technique1 has been used to evaluate the DNA strands from purified whole mitochondria released by osmotic shock, mitochondrial DNA purified on CsCl gradients [density = 1.698 gms/cc], and DNA purified on ethidium bromide CsCl gradients. The DNA appeared as linear strands up to 25 u in length and circular forms 2.2-5.2 u in circumference. In specimens prepared by osmotic shock, many strands of DNA are apparently attached to membrane fragments [Fig. 2]. When mitochondria were ruptured in hypotonic sucrose and then fixed in glutaraldehyde, the ribosomes were released for electron microscopic examination.

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