Leach Resistant Cesium and Strontium-bearing Wasteforms from Hexagonal Tungsten Bronze-Polyacrylonitrile Composite Adsorbers

2006 ◽  
Vol 932 ◽  
Author(s):  
Christopher S. Griffith ◽  
Vittorio Luca ◽  
Ferdinand Sebesta ◽  
Patrick Yee ◽  
Elizabeth Drabarek
Keyword(s):  
Composite Material ◽  
Thermal Treatment ◽  
Strontium Titanate ◽  
Tungsten Bronze ◽  
Composite Adsorbent ◽  
Spherical Morphology ◽  
Sodium Cations ◽  
Full Complement ◽  
High Concentrations ◽  
Better Than

ABSTRACTImmobilization of adsorbed Cs+ and Sr2+ on a molybdenum-doped, hexagonal tungsten bronze (HTB)-polyacrylonitrile (PAN) composite adsorbent can be achieved by heating in air at temperatures in the range 600 - 1200 °C. Thermal treatment of the parent composite material at 800 – 1000 °C undergoes a ca. 60% reduction in volume and retains its spherical morphology. For materials prepared at 800 – 1200 °C the full complement of Cs+ and the majority of Sr2+ partition into HTB phases (A∼0.16-0.3MO3; A = Cs, Sr, Na; M = Mo,W), along with sodium cations. The presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not appear to interfere with the formation of the HTB phase. The fraction (f) of Cs+ and Sr2+ leached from the tungstate phase assemblages is better or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ca. 8 × 10−5; rate = <1.2 × 10−4 g m−2d−1) and strontium titanate (SrTiO3; f = 3.1 × 10−3; rate = 2.63 × 10−4 g m−2day−1), respectively, using a modified PCT test. Furthermore, where aggressive leaching conditions are employed (0.1M HNO3; 150 °C; 4 days), the tungstate phase assemblages display leach resistance orders of magnitude better than the reference phases (Cs+ - f = ca. 5 × 10−3; rate = ca. 1.4 × 10−3 g m−2day−1; Sr2+ - f = ca. 8 × 10−2; rate = ca. 2.5 × 10−2 g m−2day−1).

Leach Resistant Cesium and Strontium-bearing Wasteforms from Hexagonal Tungsten Bronze-Polyacrylonitrile Composite Adsorbers

2006 ◽  
Vol 932 ◽  
Author(s):  
Christopher S. Griffith ◽  
Vittorio Luca ◽  
Ferdinand Sebesta ◽  
Patrick Yee ◽  
Elizabeth Drabarek
Keyword(s):  
Composite Material ◽  
Thermal Treatment ◽  
Strontium Titanate ◽  
Tungsten Bronze ◽  
Composite Adsorbent ◽  
Spherical Morphology ◽  
Sodium Cations ◽  
Full Complement ◽  
High Concentrations ◽  
Better Than

ABSTRACTImmobilization of adsorbed Cs+ and Sr2+ on a molybdenum-doped, hexagonal tungsten bronze (HTB)-polyacrylonitrile (PAN) composite adsorbent can be achieved by heating in air at temperatures in the range 600 – 1200 °C. Thermal treatment of the parent composite material at 800 – 1000 °C undergoes a ca. 60% reduction in volume and retains its spherical morphology. For materials prepared at 800 – 1200 °C the full complement of Cs+ and the majority of Sr2+ partition into HTB phases (A∼0.16-0.3MO3; A = Cs, Sr, Na; M = Mo,W), along with sodium cations. The presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not appear to interfere with the formation of the HTB phase. The fraction (f) of Cs+ and Sr2+ leached from the tungstate phase assemblages is better or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ca. 8 × 10−5; rate = <1.2 × 10−4 g m−2d−1) and strontium titanate (SrTiO3; f = 3.1 × 10−3; rate = 2.63 × 10−4 g m−2 day×1), respectively, using a modified PCT test. Furthermore, where aggressive leaching conditions are employed (0.1M HNO3; 150 oC; 4 days), the tungstate phase assemblages display leach resistance orders of magnitude better than the reference phases (Cs+ - f = ca. 5 × 10−3; rate = ca. 1.4 × 10−3 g m−2 day−1; Sr2+ - f = ca. 8 × 10−2; rate = ca. 2.5 × 10−2 g m−2 day−1).

HemoCue: Evaluation of a Portable Photometric System for Determining Glucose in Whole Blood

1992 ◽  
Vol 38 (8) ◽  
pp. 1479-1482 ◽  
Author(s):  
L Ashworth ◽  
I Gibb ◽  
K G Alberti
Keyword(s):  
Whole Blood ◽  
Glucose Dehydrogenase ◽  
Glucose Measurement ◽  
Photometric System ◽  
Analytical Recovery ◽  
Wide Range ◽  
Regression Slopes ◽  
High Concentrations ◽  
Better Than ◽  
Positive Interference

Abstract We assessed the HemoCue system for measuring glucose in 5 microL of whole blood. A glucose dehydrogenase-based reaction is used with dried reagents contained in disposable microcuvettes, which are filled with blood by capillary action. Automated hexokinase and YSI 23AM glucose analyzer methods were used for comparison. Overall imprecision (CV) was better than 4.5%, with no significant differences in results between three different HemoCue photometers and four batches of microcuvettes. Regression slopes (+/- SE) were 0.947 (0.011) with the YSI and 0.966 (0.015) with the hexokinase method. Analytical recovery of added glucose was 101-106%, and the system functioned with hematocrits up to 0.65. Bilirubin up to 453 mumol/L did not interfere, but high concentrations of endogenous (greater than 3 mmol/L) and exogenous triglycerides gave positive interference. The system proved stable and robust under a wide range of storage and handling conditions; performance was impaired only at high ambient temperature (37 degrees C). We conclude that the HemoCue system should prove useful for glucose measurement; further testing outside the laboratory is warranted.

Development of a New Kind of Sealing Composite Material Reinforced with Carbon and Glass Hybrid Fibers

2008 ◽  
Vol 44-46 ◽  
pp. 651-658 ◽  
Author(s):  
Ye Chen ◽  
Bo Qin Gu
Keyword(s):  
Composite Material ◽  
Design Method ◽  
Sem Analysis ◽  
National Standard ◽  
Hybrid Fibers ◽  
Transverse Tensile ◽  
Surface Behavior ◽  
Regression Design ◽  
The Difference ◽  
Better Than

A new kind of sealing composite material reinforced mainly with carbon and glass hybrid fibers was developed with calendar preparation method. In consideration of the difference of surface behavior, carbon fiber and glass fiber were pretreated by various surface treatment methods, and the effect of these methods on the material properties and interface bonding between fibers and matrix was studied through the transverse tensile test and SEM analysis. The optimum prescription of the sealing composite material was obtained by regression design method, adopting stress relaxation at 300°C as evaluating indicator. The performances of the developed sealing composite material were tested, and the results indicated that the main performances of the material coincided with the requirements prescribed in Chinese national standard and some performances were even better than that of the products of some famous corporations.

Immobilisation process for contaminated zeolitic ion exchangers from Fukushima

MRS Advances ◽  
2016 ◽  
Vol 1 (62) ◽  
pp. 4089-4094 ◽  
Author(s):  
D. Pletser ◽  
R. K. Chinnam ◽  
M. Kamoshida ◽  
W.E. Lee
Keyword(s):  
Composite Material ◽  
Thermal Treatment ◽  
Low Temperature ◽  
Glass Composition ◽  
Glass Frit ◽  
Maximum Temperature ◽  
Sintering Process ◽  
Volatile Species ◽  
Glass Composite ◽  
Fukushima Daiichi

AbstractThe clean-up of the Fukushima Daiichi site, after the March 2011 earthquake and tsunami, continues to generate large amounts of spent adsorbents. These adsorbents need to be disposed of permanently in a low temperature immobilisation process to avoid volatilising radioactive Cs and Sr species. To this end an immobilisation process with a maximum temperature of 600 °C was developed by sintering model waste with glass frit to form a dense Glass Composite Material (GCM) wasteform. A zeolitic model wasteform, chabazite, was sintered with a lead borosilicate glass composition at a maximum temperature of 600 °C. The sintering process was optimised with various thermal treatment steps to ensure that volatile species, aqueous or otherwise, were released before full sintering to yield a dense final wasteform. With this process dense wasteforms of up to 40 wt. % chabazite have been achieved.

Preparation and Structure Analysis of Noncrystalline Granular Starch

2010 ◽  
Vol 6 (4) ◽  
Author(s):  
Peiling Liu ◽  
Benshan Zhang ◽  
Qun Shen ◽  
Xiaosong Hu ◽  
Wenhao Li
Keyword(s):  
Thermal Treatment ◽  
Crystalline Structure ◽  
Chemical Method ◽  
Physical Method ◽  
Maize Starch ◽  
X Ray Diffraction ◽  
Preparation Methods ◽  
Peculiar Form ◽  
Freeze Dried ◽  
Better Than

Noncrystalline granular (NCG) starch is a peculiar form of starch. The granules have granular shape but no crystalline structure. It is a middle state between native semi-crystal structure and paste. The conception of NCG starch was presented and its preparation methods for native maize starch were explored. Cross-linking by chloroepoxy propane was adopted as the chemical method while ethanol treatment was adopted as the physical method. Cross bonds and ethanol were both able to protect starch granules from swelling while thermal treatment was able to destroy crystalline structure of the granules. The structure of granule was observed by polarization microscope and scanning electron microscopy (SEM). Change from crystalline to noncrystalline structure was confirmed by X-ray diffraction (XRD). It indicated that preparation of NCG starch with the physical method was better than chemical method. The detailed conditions were: maize starch (40%, w/w) was slurried in 50%-ethanol, underwent thermal treatment at 85°C for 2 minutes, washed with anhydrous ethanol (2000 ml), and freeze dried.

scholarly journals Roles of LAP2 Proteins in Nuclear Assembly and DNA Replication: Truncated LAP2β Proteins Alter Lamina Assembly, Envelope Formation, Nuclear Size, and DNA Replication Efficiency in Xenopus laevis Extracts

1999 ◽  
Vol 144 (6) ◽  
pp. 1083-1096 ◽  
Author(s):  
Tracey Michele Gant ◽  
Crafford A. Harris ◽  
Katherine L. Wilson
Keyword(s):  
Dna Replication ◽  
Xenopus Laevis ◽  
Chromatin Binding ◽  
Binding Region ◽  
Nuclear Assembly ◽  
Downstream Effector ◽  
Common Domain ◽  
Splicing Isoforms ◽  
High Concentrations ◽  
Better Than

Humans express three major splicing isoforms of LAP2, a lamin- and chromatin-binding nuclear protein. LAP2β and γ are integral membrane proteins, whereas α is intranuclear. When truncated recombinant human LAP2β proteins were added to cell-free Xenopus laevis nuclear assembly reactions at high concentrations, a domain common to all LAP2 isoforms (residues 1–187) inhibited membrane binding to chromatin, whereas the chromatin- and lamin-binding region (residues 1–408) inhibited chromatin expansion. At lower concentrations of the common domain, membranes attached to chromatin with a unique scalloped morphology, but these nuclei neither accumulated lamins nor replicated. At lower concentrations of the chromatin- and lamin-binding region, nuclear envelopes and lamins assembled, but nuclei failed to enlarge and replicated on average 2.5-fold better than controls. This enhancement was not due to rereplication, as shown by density substitution experiments, suggesting the hypothesis that LAP2β is a downstream effector of lamina assembly in promoting replication competence. Overall, our findings suggest that LAP2 proteins mediate membrane–chromatin attachment and lamina assembly, and may promote replication by influencing chromatin structure.

scholarly journals Tethered Bichromophoric Fluorophore Quencher Voltage Sensitive Dyes

2018 ◽  
Author(s):  
Ping Yan ◽  
Corey Acker ◽  
Leslie M. Loew
Keyword(s):  
Electrical Activity ◽  
Charged Membrane ◽  
Voltage Dependent ◽  
Order Of Magnitude ◽  
Hydrophobic Chain ◽  
High Concentrations ◽  
Voltage Sensitive Dyes ◽  
Better Than

ABSTRACTVoltage sensitive dyes (VSDs) are used for in vitro drug screening and for in vivo imaging of patterns of electrical activity. However, wide application of this technology is limited by poor sensitivity. A promising approach uses a 2-component system consisting of charged membrane permeable quenchers together with fluorophores labeling one side of the membrane; this produces voltage-dependent fluorescence quenching. However, to achieve good sensitivity, the quencher compound must be used at high concentrations, which can perturb the membrane capacitance or have other pharmacological effects. By developing tethered bichromophoric fluorophore quencher (TBFQ) dyes, where the fluorophore and quencher are covalently connected by a long hydrophobic chain, the concentration required is minimized, and the sensitivity is maximized. A series of 13 TBFQ dyes based on the AminoNaphthylEthenylPyridinium (ANEP) fluorophore and the dipicrylamine anion (DPA) quencher have been synthesized and tested in an artificial lipid bilayer apparatus. The best one from the screening, TBFQ1, shows a 2.5 fold change in fluorescence per 100mV change in membrane potential, and the response kinetics is in 10-20 ms range. This sensitivity is an order of magnitude better than commonly used fluorescent voltage sensors. The design principles for TBFQ VSDs described here can be readily extended to other spectral regions and promise to greatly enhance our ability to monitor electrical activity in cells and tissues.

Equilibrium and Kinetics Studies of Phosphate Removal from Solution onto a Hydrothermally Modified Al-Si-Fe-Ca Composite Adsorbent

2014 ◽  
Vol 787 ◽  
pp. 128-134
Author(s):  
Qiong Wu ◽  
Rui Rong You ◽  
Qiu Ping Wu ◽  
Fei Yun Chen ◽  
Yan Yu
Keyword(s):  
Composite Material ◽  
Wastewater Treatment ◽  
Raw Materials ◽  
Phosphate Removal ◽  
Sorption Data ◽  
Composite Adsorbent ◽  
Equilibrium And Kinetics ◽  
Pseudo Second Order ◽  
Ph Range ◽  
Maximum Removal

A novel Al–Si–Fe–Ca composite material for phosphate removal in wastewater treatment was made by using Al (OH)3,Fe2O3,CaO and silica powder as raw materials. Sorption data modelling with a pH range of 3–12, P concentrations of 3,5,7,9, 11,13, 15mg L−1, and an ambient temperature of 23°C indicated that an optimal removal of P occurred at pH 6.0. A maximum removal of 99.68% was found for 11mg L−1(pH of 6). Langmuir isotherm best described theadsorption processwith a maximumadsorption capacity of 8.60mg g−1. Three kinetic models (apseudo-first-order, a pseudo-second-order (PSO) and Elovich) were also applied,and the results showed that the PSOmodel best described the data. SEM and EDAX analysis confirmed that P was adsorbed to the surface of the composite material. This study demonstrates that the composite adsorbent is suitable for use in wastewater treatment, with P removal of the solids being preferential and spontaneous.

scholarly journals A practical approach to lake water density from electrical conductivity and temperature

2016 ◽  
Vol 20 (7) ◽  
pp. 2975-2986 ◽  
Author(s):  
Santiago Moreira ◽  
Martin Schultze ◽  
Karsten Rahn ◽  
Bertram Boehrer
Keyword(s):  
Electrical Conductivity ◽  
Common Procedure ◽  
New Approach ◽  
Circulation Patterns ◽  
Lakes And Reservoirs ◽  
High Concentrations ◽  
Lake Waters ◽  
Very High ◽  
Limited Accuracy ◽  
Better Than

Abstract. Density calculations are essential to study stratification, circulation patterns, internal wave formation and other aspects of hydrodynamics in lakes and reservoirs. Currently, the most common procedure is the use of CTD (conductivity, temperature and depth) profilers and the conversion of measurements of temperature and electrical conductivity into density. In limnic waters, such approaches are of limited accuracy if they do not consider lake-specific composition of solutes, as we show. A new approach is presented to correlate density and electrical conductivity, using only two specific coefficients based on the composition of solutes. First, it is necessary to evaluate the lake-specific coefficients connecting electrical conductivity with density. Once these coefficients have been obtained, density can easily be calculated based on CTD data. The new method has been tested against measured values and the most common equations used in the calculation of density in limnic and ocean conditions. The results show that our new approach can reproduce the density contribution of solutes with a relative error of less than 10 % in lake waters from very low to very high concentrations as well as in lakes of very particular water chemistry, which is better than all commonly implemented density calculations in lakes. Finally, a web link is provided for downloading the corresponding density calculator.

Microstructure and Superconductive Property of MgB2/Al Composite Materials

2012 ◽  
Vol 706-709 ◽  
pp. 667-670
Author(s):  
Manabu Mizutani ◽  
Daisuke Tokai ◽  
Kenji Matsuda ◽  
Katsuhiko Nishimura ◽  
Tokimasa Kawabata ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Magnetic Hysteresis ◽  
Three Dimensional ◽  
Original Method ◽  
Superconducting Transition ◽  
Bean Model ◽  
Al Composite ◽  
The Matrix ◽  
Better Than

MgB2has the higher critical temperature of superconducting transition (TC: 39K) among the intermetallic compound superconductive materials, however, MgB2is hard for practical use because of its unworkable and lower critical current density (JC) in a high magnetic field than Nb-based superconductive materials. We have developed the original method of three-dimensional penetration casting (3DPC) to fabricate the MgB2/Al composite materials. In the composite material we made, MgB2particles dispersed to the matrix uniformly. Thus, these composite materials can be processed by machining, extrusion and rolling. TheTCwas determined by electrical resistivity and magnetization to be about 37～39K. In this work, we made composite material with ground MgB2particle with the purpose of extruding thinner wires of composite material, successfully produced φ1mm wire and changed the matrix from pure Al to Al-In alloy.JCof composite materials with the matrix of Al-In alloy was calculated from the width of the magnetic hysteresis based on the extended Bean model. The result was better than that of MgB2/Al composite material without Indium. Microstructures of these samples had been confirmed by SEM observation.

Sign in / Sign up

Export Citation Format

Share Document