Advanced ePrometheus™ GNF fuel cycle optimization tool

This paper presents the advanced version of ePrometheus™ GNF Fuel Cycle Optimization Tool. ePrometheus is Global Nuclear Fuel-Americas LLC (“GNF”) patented computer system used to optimize Boiling Water Reactor (BWR) fuel management and operations. The advanced version of ePrometheus utilizes a new database structure (Oracle 11 g) and a new C#, WPF based graphical user interface (GUI), and employs a capability of performing refueling calculation. It also displays additional 2-D and 3-D core simulation data that are necessary to improve the fuel cycle design process, and utilizes many more advanced features based on user experience feedback. The objective of this paper is to present new advanced infrastructure of the system, and to provide overall information on the advanced features of the newly released version 3.0.     

Functional Group Effects of New Calixarene Derivatives on Catalytic and Enantioselective Behavior of Lipase

ABSTRACT

In this study, two new calixarene derivatives bearing thiourea and carbamate moieties were synthesized and characterized. Moreover, thiourea- and carbamate-bridged calixarene derivatives with Fe₃O₄ magnetic nanoparticle were employed for the first time as the convenient additives in the encapsulation process of lipase. The results of catalytic activity and enantioselectivity of the encapsulated lipases in the hydrolysis reaction of racemic flurbiprofen methyl ester indicate that both of the encapsulated lipases (Enc-TuC[4]@Fe₃O₄ and Enc-CbC[4]@Fe₃O₄) exhibit higher conversion and enantioselectivity compared to the free-encapsulated lipase (Enc-Lipase). However, the highest affinities result was obtained when the encapsulated lipase (Enc-CbC[4]@Fe₃O₄) was used in the kinetic resolution reaction of racemic flurbiprofen methyl ester.     

The influence of reactive milling on the structure and magnetic properties of nanocrystalline MnFe2O4

Nanocrystalline manganese ferrites (MnFe₂O₄) have been synthesized by direct milling of metallic manganese (Mn) and iron (Fe) powders in distilled water (H₂O). In order to overcome the limitation of wet milling, dry milling procedure has also been utilized to reduce crystallite size. The effects of milling time on the formation and crystallite size of wet milled MnFe₂O₄ nanoparticles have been investigated. It has been observed that single phase 18.4 nm nanocrystalline MnFe₂O₄ is obtained after 24 h milling at 400 rpm. Further milling caused deformation of the structure as well as increased crystallite size. With the aim of reducing the crystallite size of 18.4 nm, MnFe₂O₄ sample dry milling has been implemented for 2 and 4 h at 300 rpm. As a result, the crystallite size has been reduced to 12.4 and 8.7 nm, respectively. Effects of the crystalline sizes on magnetic properties were also investigated. Magnetization results clearly demonstrated that crystallite size has much more effect on the magnetic properties than average particle size.     

A supramolecular sensing platform for phosphate anions and an anthrax biomarker in a microfluidic device

A supramolecular platform based on self-assembled monolayers (SAMs) has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detection. A Eu(III)-EDTA complex was bound to β-cyclodextrin monolayers via orthogonal supramolecular host-guest interactions. The self-assembly of the Eu(III)-EDTA conjugate and naphthalene β-diketone as an antenna resulted in the formation of a highly luminescent lanthanide complex on the microchannel surface. Detection of different phosphate anions and aromatic carboxylic acids was demonstrated by monitoring the decrease in red emission following displacement of the antenna by the analyte. Among these analytes, adenosine triphosphate (ATP) and pyrophosphate, as well as dipicolinic acid (DPA) which is a biomarker for anthrax, showed a strong response. Parallel fabrication of five sensing SAMs in a single multichannel chip was performed, as a first demonstration of phosphate and carboxylic acid screening in a multiplexed format that allows a general detection platform for both analyte systems in a single test run with μM and nM detection sensitivity for ATP and DPA, respectively.     

Removal of cationic dyes from aqueous solutions with poly (<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide-<Emphasis Type="Italic">co</Emphasis>-itaconic acid) hydrogels

In this study, N-isopropylacrylamide-based temperature and pH-sensitive hydrogels were synthesized by free radical polymerization for removal of cationic dyes from aqueous solutions. For this purpose, N-isopropylacrylamide was copolymerized with various amounts of sodium salt of itaconic acid in the presence of crosslinking agent (N,N-methylene bisacrylamide). The chemical structures of hydrogels were characterized by FT-IR analysis. In order to investigate swelling properties of the hydrogels, water absorption (swelling) and shrinking (deswelling) kinetics, the equilibrium swelling ratios in water and different pH buffer solutions, and the temperature dependent swelling ratios were determined. Then, their adsorption properties such as adsorption capacities, kinetics, isotherms were investigated in case of their usage in removal of Safranine T (ST), Brilliant Green (BG), and Brilliant Cresyl Blue (BCB) aqueous solutions. According to adsorbed dye amount, the adsorption capacities are followed the order BG > ST ≅ BCB. In addition, the results indicated that the pseudo-second-order kinetic model fitted better than the data obtained from pseudo-first-order model for the adsorption of all dyes onto hydrogels. Furthermore, according to effect of the initial dye concentration findings, it is concluded that, Freundlich isotherm explains the adsorption better than Langmuir isotherm.     

Synthesis of amphiphilic triblock copolymers for the formation of magnesium fluoride (MgF2) nanoparticles

A series of amphiphilic poly(2‐hydroxyethyl methacrylate)‐b‐polydimethylsiloxane‐b‐poly(2‐hydroxyethyl methacrylate) (pHEMA‐b‐PDMS‐b‐pHEMA) (A‐B‐A) triblock copolymers were synthesized from three different carbinol‐terminated polydimethylsiloxanes with varying molecular weight. A carbinol‐terminated polydimethylsiloxane was modified with 2‐bromoisobutyryl bromide to obtain a macroinitiator. The block copolymers were characterized by NMR, GPC, and dynamic light scattering (DLS). Reverse micelles of a copolymer were formed in mixture of benzene/methanol solution which served as nanoreactors for the synthesis of magnesium fluoride (MgF₂) nanoparticles. The MgF₂ was prepared via chemical precipitation using magnesium chloride and potassium fluoride as reactants. The MgF₂‐triblock copolymer composites were synthesized as a function of MgF₂–weight ratio (0.5, 5, and 10 wt%) in copolymer. The MgF₂ colloids were dissolved in three organic solvents: methanol, isopropanol, and tetrahydrofuran. The polymer nanoparticles were characterized by DLS, transmission electron microscopy, thermogravimetric analysis, and X‐ray diffraction (XRD) analysis. The formation of MgF₂ crystals was observed by XRD. Particle size and particle size distribution showed significant changes in different solvents. The thermal stability of MgF₂ colloids increased as the amount of nanoparticle increased in polymeric matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polyindene/organo‐montmorillonite conducting nanocomposites. I. Synthesis,characterization, and electrokinetic properties

In this study, Na‐montmorillonite was organically modified with cetyltrimethylammoniumbromide (CTAB) and intercalated with in‐situ polymerized indene. Polyindene(PIn)/Organo‐MMT nanocomposites were obtained with three different compositions and coded as: K1: [PIn(94.5%)/O‐MMT(5.5%)], K2: [PIn(92.8%)/O‐MMT(7.2%)], and K3: [PIn(87.9%)/O‐MMT(12.1%)]. These nanocomposites were subjected to full characterization with various techniques. Electrokinetic studies were conducted to reveal the zeta (ζ)‐potential characteristics of the nanocomposites. ζ‐potentials of the materials were observed to decrease with increasing O‐MMT content. The cationic (CTAB) and anionic (sodium dodecylsulfate) surfactants were shifted the ζ‐potentials of the colloidal dispersions to more positive and more negative regions, respectively whereas nonionic surfactant (Triton X‐100) caused almost no change. The pH and temperature were observed to shift the ζ‐potential values of the nanocomposites to more negative and slightly more positive regions, respectively. With the addition of mono (NaCl), di (BaCl₂) and three (AlCl₃) valent salts, the ζ‐potential of the nanocomposites were shifted to more negative, more positive, and much more positive regions, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermal Behaviors of Bisazocalix[4]arene Derivatives

In this article, calix[4]arene (4) was prepared by debutylation and hydrolyses reacting from 25,27-dibenzoyl-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl)calix[4]arene (2). Azocalix[4]arenes (6a-c) were coupled by linking 4-methoxy, 4-ethyl, and 4-nitroaniline to calix[4]arene (4) through a diazo-coupling reaction. Thermal behavior characteristics and decomposition routes of 25,26,27,28-tetrahydroxy-11,23-di(tert-butyl)-5,17-(p-substitue phenyl)azocalix[4]arene (6a-c) were investigated in air atmosphere by means of thermogravimetry (TG), differential thermogravimetry (DTG), and differential thermal analysis (DTA) analyses. It was found that the decomposition of all compounds complete with two exothermic stages which corresponded to removal of substitute groups (methoxy-, ethyl-, nitro-) and second stage rest of structure decomposition.     

Removal of Cu2+ and Pb2+ ions from aqueous solutions by starch-graft-acrylic acid/montmorillonite superabsorbent nanocomposite hydrogels

In this study, the removal of copper(II) and lead(II) ions from aqueous solutions by Starch-graft-acrylic acid/montmorillonite (S-g-AA/MMT) nanocomposite hydrogels was investigated. For this purpose, various factors affecting the removal of heavy metal ions, such as treatment time with the solution, initial pH of the solution, initial metal ion concentration, and MMT content were investigated. The metal ion removal capacities of copolymers increased with increasing pH, and pH 4 was found to be the optimal pH value for maximum metal removal capacity. Adsorption data of the nanocomposite hydrogels were modeled by the pseudo-second-order kinetic equation in order to investigate heavy metal ions adsorption mechanism. The observed affinity order in competitive removal of heavy metals was found Cu²⁺ > Pb²⁺. The Freundlich equations were used to fit the equilibrium isotherms. The Freundlich adsorption law was applicable to be adsorption of metal ions onto nanocomposite hydrogel.