scholarly journals Preliminary Study of Using Colloidal SiO2@ZrO2 Particles in Recovering Actinides from Water and Immobilizing them in a Glass-Ceramic

2021 ◽  
Author(s):  
Pablo Arnal ◽  
Ariana Salvia
Keyword(s):  
Thermal Treatment ◽  
Size Distribution ◽  
Experimental Work ◽  
Outer Surface ◽  
Glass Ceramic ◽  
Batch Experiments ◽  
Batch Systems ◽  
Complex Process ◽  
Broad Size Distribution ◽  
Preliminary Study

Actinides, which are toxic for humans, increased their presence in the hydrosphere over the last 80 years. Though actinide recovery from water and immobilization for safe storage is technically feasible, it remains a complex process. Herein, we preliminary studied SiO2@ZrO2 in recovering actinides from water and trapping them in a glass-ceramic upon thermal treatment. To simplify our experimental work, we surrogated radioactive actinides with stable cerium. In the first part of the work, we tested SiO2@ZrO2's ability to recover Ce from water in batch systems. Then, we thermally treated SiO2@ZrO2 with Ce to form a glass-ceramic. All batch experiments showed that SiO2@ZrO2 removes Ce from water. Moreover, all experiments show that SiO2@ZrO2 with Ce converts into a glass-ceramic upon thermal treatment. When heated up to 1000 °C, particles remained spherical, and Ce remained trapped within the structure of crystalline spheroids located between the outer surface and a 50 nm depth. When heated up to 1450 °C, sintering produced bigger particles than the original colloid, and Ce remained trapped within the structure of crystalline spheroids having a broad size distribution located everywhere in the particles.

654. A rapid method for estimating the size distribution of fat globules in cream

1957 ◽  
Vol 24 (1) ◽  
pp. 68-76 ◽  
Author(s):  
R. M. Dolby
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Rapid Method ◽  
Experimental Work ◽  
Flat Bottom ◽  
Fat Globules ◽  
Total Fat ◽  
Conical Flask

The proportion of fat present in cream as small globules (approximately 1 μ and under) is estimated from the proportion of the total fat which remains in the serum when a sample of the cream, diluted to 10% fat, is centrifuged at 60° C. for 30 min. at 3000 r.p.m.The fat present as large globules (7 or 8μ and over) is estimated by finding the proportion of the fat which rises 1 cm. in 60 min. when the cream, diluted to 10% fat, is held at 60° C. in a modification of the Andreasen particle-size apparatus in which the jar is replaced by a conical flask and the tip of the sampling pipette is held 1 cm. from the flat bottom of the flask.The thanks of the author are due to Dr F. H. McDowall for helpful advice and criticism and to Miss R. P. Johnson for assistance with the experimental work.

scholarly journals Tubulin Beta-3 Chain as a New Candidate Protein Biomarker of Human Skin Aging: A Preliminary Study

2017 ◽  
Vol 2017 ◽  
pp. 1-21 ◽  
Author(s):  
Sylvia G. Lehmann ◽  
Sandrine Bourgoin-Voillard ◽  
Michel Seve ◽  
Walid Rachidi
Keyword(s):  
Gene Expression ◽  
Elderly Women ◽  
Skin Aging ◽  
Primary Keratinocytes ◽  
Cellular Processes ◽  
Complex Process ◽  
Skin Biopsies ◽  
Candidate Protein ◽  
Preliminary Study ◽  
Human Primary Keratinocytes

Skin aging is a complex process, and a lot of efforts have been made to identify new and specific targets that could help to diagnose, prevent, and treat skin aging. Several studies concerning skin aging have analyzed the changes in gene expression, and very few investigations have been performed at the protein level. Moreover, none of these proteomic studies has used a global quantitative labeled proteomic offgel approach that allows a more accurate description of aging phenotype. We applied such an approach on human primary keratinocytes obtained from sun-nonexposed skin biopsies of young and elderly women. A total of 517 unique proteins were identified, and 58 proteins were significantly differentially expressed with 40 that were downregulated and 18 upregulated with aging. Gene ontology and pathway analysis performed on these 58 putative biomarkers of skin aging evidenced that these dysregulated proteins were mostly involved in metabolism and cellular processes such as cell cycle and signaling pathways. Change of expression of tubulin beta-3 chain was confirmed by western blot on samples originated from several donors. Thus, this study suggested the tubulin beta-3 chain has a promising biomarker in skin aging.

scholarly journals Conducting Membranes and Coatings made from Redispersable Nanoscaled Crystalline SnO2:Sb Particles

1998 ◽  
Vol 520 ◽  
Author(s):  
C. Goebbert ◽  
M. A. Aegerter ◽  
D. Burgard ◽  
R. Nass ◽  
H. Schmidt
Keyword(s):  
Thermal Treatment ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Sol Gel ◽  
Total Porosity ◽  
Solid Content ◽  
Visible Range ◽  
Inorganic Membranes ◽  
Separation Processes

ABSTRACTInorganic membranes prepared by the sol gel method are promising candidates for use as filters in separation processes. Conducting supported membranes and coatings have been produced from redispersable nanoscaled crystalline Sb-doped SnO2 powders with a Sb content up to 5 mole % (with respect to Sn). The crystalline particles are monosized (≅4 nm) and fully redispersable in aqueous solution at pH ≥ 8 with a solid content up to 70 wt. %. By thermal treatment at different temperatures and times, the pore size diameter of the material can be adjusted from 4 to 20 nm with a very narrow pore size distribution (∼ ±1 nm) and a total porosity of 63 %, practically independent of the sintering parameters. Uniaxial pressed substrates present similar characteristics with however larger pore size distribution (±5 nm) and 80 % total porosity. Their resistance decreases with sintering temperature and time down to 4 Ω (800 °C 8 h). Fully dispersed aqueous solutions of the powder (25 wt. %) were used to prepare transparent conducting coatings on glass or ceramics by spin-coating. After thermal treatment (1 hour at 550 °C) single layers 200 nm thick exhibited a typical specific electrical resistance ρ = 2.5·10−2 ωcm with transmission in the visible range measured against air of 90%.

scholarly journals Bacteriophage Inactivation at the Air-Water-Solid Interface in Dynamic Batch Systems

1999 ◽  
Vol 65 (3) ◽  
pp. 1186-1190 ◽  
Author(s):  
Shawn S. Thompson ◽  
Marylynn V. Yates
Keyword(s):  
Ionic Strength ◽  
Hydrophobic Surface ◽  
Tween 80 ◽  
Batch Experiments ◽  
Virus Transport ◽  
Viral Inactivation ◽  
Solid Interface ◽  
Batch Systems ◽  
Surface Active ◽  
Surface Active Compounds

ABSTRACT Bacteriophages have been widely used as surrogates for human enteric viruses in many studies on virus transport and fate. In this investigation, the fates of three bacteriophages, MS2, R17, and φX174, were studied in a series of dynamic batch experiments. Both MS2 and R17 readily underwent inactivation in batch experiments where solutions of each phage were percolated through tubes packed with varying ratios of glass and Teflon beads. MS2 and R17 inactivation was the result of exposure to destructive forces at the dynamic air-water-solid interface. φX174, however, did not undergo inactivation in similar studies, suggesting that this phage does not accumulate at air-water interfaces or is not affected by interfacial forces in the same manner. Other batch experiments showed that MS2 and R17 were increasingly inactivated during mixing in polypropylene tubes as the ionic strength of the solution was raised (φX174 was not affected). By the addition of Tween 80 to suspensions of MS2 and R17, phage inactivation was prevented. Our data suggest that viral inactivation in simple dynamic batch experiments is dependent upon (i) the presence of a dynamic air-water-solid interface (where the solid is a hydrophobic surface), (ii) the ionic strength of the solution, (iii) the concentration of surface active compounds in the solution, and (iv) the type of virus used.

scholarly journals Assessing the degradation of ochratoxin a using a bioassay: the case of contaminated winery wastewater

2007 ◽  
Vol 56 (2) ◽  
pp. 55-61 ◽  
Author(s):  
R. Nogueira ◽  
I. Estevinho ◽  
L. Abrunhosa ◽  
C. Mendonça ◽  
P. Machado ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Microbial Activity ◽  
Ochratoxin A ◽  
Experimental Work ◽  
Biomass Concentration ◽  
Biological Degradation ◽  
Batch Experiments ◽  
Wastewater Treatment Systems ◽  
Conventional Wastewater Treatment

In vineyards the presence of certain fungi may lead to the production of the mycotoxin ochratoxin A (OTA) and subsequent contamination of grapes and wine. Furthermore, winery wastewaters contaminated with OTA may represent an environmental hazard. Therefore, it is imperative to assess the fate of this mycotoxin in conventional wastewater treatment systems. The aim of the present work was to assess the biological degradation of OTA. Experimental work was carried out in batch experiments with initial OTA to biomass concentration ratios of 1.4 μg mg−1, 7.4 μg mg−1 and, 11.9 μg mg−1. The assays were inoculated with activated sludge biomass unadapted to the substance under examination. The proposed bioassay demonstrates that OTA concentrations up to 100 μg L−1 can be degraded by microbial activity in activated sludge.

Preliminary study of elemental mass size distribution of urban aerosol collected in Debrecen, Hungary

1999 ◽  
Vol 30 ◽  
pp. S273-S274 ◽  
Author(s):  
Zs. Kerte´sz ◽  
I. Borbe´ly-Kiss ◽  
A´.Z. Kiss ◽  
E. Koltay ◽  
Gy. Szabo´
Keyword(s):  
Size Distribution ◽  
Urban Aerosol ◽  
Mass Size Distribution ◽  
Mass Size ◽  
Preliminary Study ◽  
Elemental Mass

From tar sands to synthetic crude: Applications of microscopy

1988 ◽  
Vol 46 ◽  
pp. 938-939
Author(s):  
R.J. Mikula ◽  
V.A. Munoz
Keyword(s):  
Electron Microscope ◽  
Chemical Composition ◽  
Crude Oil ◽  
Optical Microscopy ◽  
Size Distribution ◽  
Hot Water ◽  
Dispersed Phase ◽  
Tar Sands ◽  
Initial Separation ◽  
Complex Process

The production of synthetic crude oil from tar sands is a complex process involving initial separation of the bitumen from the sand via the hot water process, separation of the bitumen from the water and finally coking of the residual bitumen to maximize the yield of crude oil. Many of the processing concerns center around decreasing the amount of water and clay which is carried with the bitumen product and decreasing the amount of bitumen which is carried with the water, sand and clay tailings. The crude oil yield in the final coking step is then dependent upon the efficiency of these preliminary steps as well as the coking conditions.Both electron and optical microscopy have important applications in understanding these systems. Direct observation of frozen hydrated samples in the electron microscope has been utilized for evaluation of both the size distribution of the dispersed phase and the chemical composition.

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