scholarly journals Synthesis of simulant ‘lava-like’ fuel containing materials (LFCM) from the Chernobyl reactor Unit 4 meltdown

MRS Advances ◽  
2016 ◽  
Vol 2 (11) ◽  
pp. 609-614 ◽  
Author(s):  
Sean T. Barlow ◽  
Daniel J. Bailey ◽  
Adam J. Fisher ◽  
Martin C. Stennett ◽  
Claire L. Corkhill ◽  
...  
Keyword(s):  
Preliminary Investigation ◽  
Glassy Matrix ◽  
Dissolution Behavior ◽  
Controlled Cooling ◽  
Reactor Unit ◽  
Reducing Atmosphere ◽  
Rate Of Dissolution ◽  
Chernobyl Reactor ◽  
Low Activity

ABSTRACTA preliminary investigation of the synthesis and characterization of simulant ‘lava-like’ fuel containing materials (LFCM), as low activity analogues of LFCM produced by the melt down of Chernobyl Unit 4. Simulant materials were synthesized by melting batched reagents in a tube furnace at 1500 °C, under reducing atmosphere with controlled cooling to room temperature, to simulate conditions of lava formation. Characterization using XRD and SEM-EDX identified several crystalline phases including ZrO2, UOx and solid solutions with spherical metal particles encapsulated by a glassy matrix. The UOX and ZrO2 phase morphology was very diverse comprising of fused crystals to dendritic crystallites from the crystallization of uranium initially dissolved in the glass phase. This project aims to develop simulant LFCM to assess the durability of Chernobyl lavas and to determine the rate of dissolution, behavior and evolution of these materials under shelter conditions.

scholarly journals An Historical Mullite Fiber-Reinforced Ceramic Composite: Characterization of the ‘Wootz’ Crucible Refractory

1990 ◽  
Vol 185 ◽  
Author(s):  
Thelma L. Lowe ◽  
Nima Merk ◽  
Gareth Thomas
Keyword(s):  
Ceramic Composite ◽  
Raw Materials ◽  
Glassy Matrix ◽  
Rice Husks ◽  
Single Cycle ◽  
Damascus Steel ◽  
Reducing Atmosphere ◽  
Mullite Fiber ◽  
Two Phases

AbstractSince at least the sixteenth century, the ‘wootz’ ultra-high carbon white cast-iron ingot was produced in India by melting or carburising iron in a crucible. This ingot was forged into sword blades of so-called ‘Damascus’ steel. The charged crucible was fired in a long (24 hour) single cycle at high temperature (1150-1250°C) in a strongly reducing atmosphere. Raw materials for the refractory vessel are clay and ‘coked’ rice husks. At high temperatures, two phases reinforce the glassy matrix - cristobalite relics of rice husks and a network of mullite crystals. This paper characterizes the microstructure and chemistry of the mullite network in the glassy matrix by means of a combination of techniques: optical microscopy, XRD, SEM, TEM with EDS, and HREM.

Physicochemical Characterization of Solid Dispersions of Cefdinir with PVP K-30 and PEG 4000

2010 ◽  
Vol 3 (2) ◽  
pp. 948-956
Author(s):  
Kumar P ◽  
S Kumar ◽  
A Kumar ◽  
M Chander
Keyword(s):  
Solid Dispersions ◽  
Physicochemical Characterization ◽  
Drug Carriers ◽  
Dissolution Properties ◽  
Rate Of Dissolution ◽  
Peg 4000 ◽  
Release Studies ◽  
Crystalline Nature ◽  
Physical Mixtures

The purpose of this study was to prepare and characterize solid dispersions of the antibacterial agent Cefdinir with PEG 4000 and PVP K-30 with a view to improve its dissolution properties. Investigations of the properties of the dispersions were performed using release studies, X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR). The results obtained showed that the rate of dissolution of Cefdinir was considerably improved when formulated in solid dispersions with PVP K-30 and PEG 4000 as compared with pure drug and physical mixtures. The results from XRD studies showed the transition of crystalline nature of drug to amorphous form, while FTIR studies demonstrated the absence of drug-carriers interaction.

scholarly journals Purification and Characterization of Asparaginase fromPhaseolus vulgarisSeeds

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Saleh A. Mohamed ◽  
Mohamed F. Elshal ◽  
Taha A. Kumosani ◽  
Alia M. Aldahlawi
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia ◽  
Potential Candidate ◽  
Purification And Characterization ◽  
Apparent Homogeneity ◽  
Wide Range ◽  
Optimum Ph ◽  
Glutaminase Activity ◽  
Low Activity

L-asparaginase from bacteria has been used in treatment of acute lymphoblastic leukemia. The aim of this study was to purify and characterize L-asparaginase fromPhaseolus vulgarisseeds instead of microbial sources. L-asparaginase was purified to apparent homogeneity. The enzyme has molecular mass of 79 kDa. The purified asparaginase had very low activity toward a number of asparagine and glutamine analogues. L-asparaginase was free from glutaminase activity. Kinetic parameters, Km andVmax of purified enzyme, were found to be 6.72 mM and 0.16 μM, respectively. The enzyme had optimum pH at 8.0. The enzyme showed high stability at alkaline pH (pH 7.5–9.0) when incubated for up to 24 h. L-asparaginase had the same temperature optimum and thermal stability at 37°C. K+was able to greatly enhance the activity of asparaginase by 150% compared with other metals tested. In conclusion, L-asparaginase showed no glutaminase activity and good stability over a wide range of physiological conditions, and thus it could be used as a potential candidate for treatment of acute lymphoblastic leukemia.

scholarly journals Preliminary Investigation of the Dissolution Behavior, Cytocompatibility, Effects of Fibrinogen Conformation and Platelet Adhesion for Radiopaque Embolic Particles

2013 ◽  
Vol 4 (3) ◽  
pp. 89-113 ◽  
Author(s):  
Sharon Kehoe ◽  
Marie-Laurence Tremblay ◽  
Aisling Coughlan ◽  
Mark Towler ◽  
Jan Rainey ◽  
...  
Keyword(s):  
Platelet Adhesion ◽  
Preliminary Investigation ◽  
Dissolution Behavior

Characterization of Selenium Doped Silica Gels Synthesized by Sol-Gel Method

2014 ◽  
Vol 805 ◽  
pp. 564-569
Author(s):  
Renata Andrade Kobayashi ◽  
Samuel Marcio Toffoli
Keyword(s):  
Sol Gel ◽  
Silica Gels ◽  
Glassy Matrix ◽  
Industrial Glass ◽  
Rare Element ◽  
Gel Method ◽  
Sol Gel Method ◽  
Red Color ◽  
Synthesized Materials

Selenium is a rare element in nature. It is used in the food, pharmaceutical, and glass industries. In commercial glasses, selenium is the element responsible for most of the pink or light red color, but its effect is primarily dependent on the oxidation state of the element in the glassy matrix. Besides, selenium is highly volatile, and as high as 80 wt% may be lost in the furnace during the industrial glass elaboration. The sol–gel method yields synthesized materials of high purity and homogeneity, and uses low processing temperatures. Samples of silica gels were obtained by sol-gel method, incorporating precursors of selenium, with the main objective of reducing selenium losses during its heating. The results of optical absorption, XRD and thermal analysis (TGA, DSC) of the gels are presented and discussed.

Characterization of a low-activity allele of NADP+-dependent isocitrate dehydrogenase from Drosophila melanogaster

1983 ◽  
Vol 21 (7-8) ◽  
pp. 725-733 ◽  
Author(s):  
Michael M. Bentley ◽  
Roy G. Meidinger ◽  
John H. Williamson
Keyword(s):  
Drosophila Melanogaster ◽  
Isocitrate Dehydrogenase ◽  
Low Activity

Characterization of green clay concretions from the Tonggao Formation, South China: Mineralogy, petrogenesis and paleoenvironmental implications1National Natural Science Foundation of China 40825006.

2012 ◽  
Vol 49 (9) ◽  
pp. 1018-1026 ◽  
Author(s):  
Matthew R.M. Izawa ◽  
Roberta L. Flemming ◽  
Renbin Zhan ◽  
Jisuo Jin
Keyword(s):  
South China ◽  
Preliminary Investigation ◽  
Water Environment ◽  
Mineral Chemistry ◽  
Early Diagenesis ◽  
Surrounding Matrix ◽  
Lower Ordovician ◽  
Green Clay ◽  
Biodiversity Decline

Enigmatic millimetre-scale micro-concretions with pseudocrystal faces and dominated by green clay minerals occur in unfossiliferous siliciclastic mudstone of the Lower Ordovician (479.0–466.0 Ma) Tonggao Formation, South China. The fossil-free mudstone unit is associated with local biodiversity decline. The mineralogy and mineral chemistry of these concretions were unknown previously, and this study comprises a preliminary investigation. The concretions are dominated by Fe-rich phyllosilicate minerals including glauconite and clinochlore, with minor quartz and traces of magnetite. The textural relations between the micro-concretions and the surrounding matrix, and the preservation of original mudstone laminations within the concretions, point to an origin during early diagenesis. The mineralogy and chemistry of these concretions are consistent with an origin in a restricted, hypersaline, relatively deep-water environment, in accordance with stratigraphical and paleonotological data. These micro-concretions provide clues for a stressed environment with poor water circulation and anomalies of salinity and oxygen.

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