Partitioning of High-Level Waste with an Extractant Based on Chlorinated Cobalt Dicarbollide and Dibutylphosphoric Acid Zirconium Salt

A new extractant allowing full partitioning of high-level waste was developed. It consists of chlorinated cobalt dicarbollide, dibutylphosphoric acid zirconium salt, and polyethylene glycol, dissolved in a polar diluent, mononitrobenzotrifluoride. This extractant recovers from the Purex process raffinate REE, TPE, Cs, Sr, Mo, and Zr. The component ratio ensuring maximal recovery of REE and TPE was found. The majority of the above-mentioned elements are extracted by the cation-exchange mechanism, with the recovery increasing as the aqueous phase acidity is decreased. The composition of the extractable species and the stoichiometry of extraction exchange reactions with REE and TPE were studied.     

Effect of Irradiation on Hydrodynamic Properties of Extraction Mixtures Based on Carboxylic Acid Diamides in FS-13 Diluent

Radiochemistry - The hydrodynamic properties of three promising extraction mixtures, 0.05 M solutions of 2,2′-bi-pyridine-6,6′-dicarboxylic acid di(N-ethyl-4-hexylanilide) (DYP-7),...     

Experimental and Predicted Viscosities of Binary Mixtures Containing Chlorinated and Oxygenated Compounds

This study presents the viscosities, both kinematic and dynamic, of binary mixtures of 1-chlorobutane, 2-chlorobutane, or 1-chloro-2-methylpropane with butyl ethyl ether or methyl tert-butyl ether from $T = 283.15$  K to $T = 313.15$  K at atmospheric pressure as a function of composition. Kinematics viscosities were measured using an Ubbelohde viscometer. The dynamic viscosities were obtained from experimental kinematic viscosities and previously reported density data. The viscosity results have been employed to check the reliability of the Wu-UNIFAC method.     

Structural and Electrical Properties of Cobalt Ferrite

Ferrites are a class of cohesive new materiafs required for many specialised applications. Cobalt ferrite (CoFe2O4) has been identified as a substitute for carbon and serves as a non consumable anode for an eco-friendly and energy efficient production of aluminium. Pellets of cobalt ferrite have been prepared by powder metallurgical process and their electrical properties have been investigated from ambient temperature to 1273 K. The structural and morphological features have been studied by X-ray diffraction and scanning electron microscopy The relationships between such properties, chemical composition and sintering temperatures are thoroughly discussed.     

Dissolution Characteristics of Benzoic Acid and Salicylic Acid Mixtures in Reactive Media

The dissolution rates of mixtures of the two acids, benzoic acid and salicylic acid were determined in a phosphate buffered medium. Dissolution properties from compressed discs under sink conditions were essentially linear. Plots of dissolution rate versus compact composition deviated from the two component models for both non-interacting and interacting components. Dissolution rates, particularly for benzoic acid at intermediate weight fractions, were lower than predicted by the theory for two non-interacting components. These lower than expected rates were explained in terms of the physicochemical changes occurring in the microenvironment at the solid liquid interface.     

Dissolution Characteristics of Benzoic Acid and Salicylic Acid Mixtures in Reactive Media

Abstract

The dissolution rates of mixtures of the two acids, benzoic acid and salicylic acid were determined in a phosphate buffered medium. Dissolution properties from compressed discs under sink conditions were essentially linear. Plots of dissolution rate versus compact composition deviated from the two component models for both non-interacting and interacting components. Dissolution rates, particularly for benzoic acid at intermediate weight fractions, were lower than predicted by the theory for two non-interacting components. These lower than expected rates were explained in terms of the physicochemical changes occurring in the microenvironment at the solid liquid interface.     

Transport Properties of Inhomogeneous Fluid Mixtures

Explicit expressions for the transport coefficients of mixtures of dense, strongly inhomogeneous fluids are derived in terms of the equilibrium structure factors of such mixtures, in the framework of the nonequilibrium statistical mechanical theory suggested by the authors. Particular attention is paid to the diffusion coefficients of multicomponent inhomogeneous fluids. The case of binary diffusion in inhomogeneous fluids is considered in detail.     

Magnetoresistance Properties in Manganese and Cobalt Oxides

The magnetoresistance of different manganites and cobaltites is reviewed. Special attention is paid to the chemical influence on the colossal magnetoresistance properties of charge-ordered and Mn(IV) rich manganites. Cobalt oxides form a very promising family of phases with complex magnetic properties and more interesting magnetoresistance.     

Extractive Properties of P,P'-Di(2-ethylhexyl) Dihydrogen 1-Hydroxyethane-1,1-diphosphonate in Nitric Acid Solutions

Extraction of microamounts of U(VI), Th(IV), Am(III), and rare-earth elements from aqueous HNO₃ solutions with solutions of P,P'-di(2-ethylhexyl) dihydrogen 1-hydroxyethane-1,1-diphosphonate in organic diluents was studied. The stoichiometries of the extractable complexes were determined, and the effect of organic diluent on the extraction was considered. P,P'-Di(2-ethylhexyl) dihydrogen 1-hydroxyethane-1,1-diphosphonate extracts Am(III) more efficiently than does P,P'-di(2-ethylhexyl) dihydrogen methanediphosphonate.     

Viscoelastic Properties of Organic Hybrid of Chlorinated Polythylene and Small Molecule

Viscoelastic properties of an organic hybrid of chlorinated polyethylene (CPE) and N,Ndicyclohexyl-benzthiazyl-2-sulfenaamid (DZ) are investigated. All CPE/DZ hybrids show a single loss tangent (Fan δ ) peak. Its position shift linearly to higher temperature and its maximum value increases nonlinearly with increasing DZ content. The energy absorptinity (EA, a ratio of loss modulus to complex modulus) is used to characterize these hybrids. The DZ content dependence of EA changes at a critical value. The existence of a bending point in the DZ content dependence of glass transition temperature and energy absorptinity is due to the microseparation and the crystallization of DZ molecules in CPE/DZ hybrids with high DZ content. The molecular structural model can successfully explain the influence of dispersion state of DZ molecules in the matrix polymer CPE on the maximum value and the position of Tan δ of CPE/DZ hybrids.     

Evaluation of Some Properties of Powder Mixtures

Following previous work on the relation between tablet weight variation and the measured flow properties of direct tabletting vehicles, a study was made on binary powder mixtures. Two different tablet vehicles were used, Dipac and lactose while the added drug was fine aspirin.

Flow properties of various mixtures (up to 40% aspirin by weight) were measured in a Flow Factor Tester and tablet weight variation was also established. It was found that little inter-relationship exists between the shear cell parameters (flow factor and effective angle of friction) and the coefficient of tablet weight variation. It is suggested that one reason for the lack of correlation is the mixtures are complex and in addition have angles of friction which vary considerably with consolidating load.     

Swelling Properties of Gelatin in Solvent Mixtures

Abstract

Gelatin is used as one component in ink receiving layers of some ink jet papers or foils. An important property for this application is the rapid absorption of solvents. We investigated the uptake of water and water diethylene glycol (DEG) mixtures of unsupported films of gelatin as a model system. The kinetics of the swelling properties of different types of gelatin were studied as a function ofpht and DEG content. The influence of additives upon the swelling of gelatin are discussed.     

Compaction Properties of Spheronized Binary Granular Mixtures

Two spheronized granular formulations containing 20% anhydrous lactose/80% microcrystalline cellulose (MCC) and 80% anhydrous lactose/20% microcrystalline cellulose were blended in various proportions and compressed. Physical-mechanical properties of the resulting compacts were investigated using tableting indices and compared with powder mixtures of the same compositions. The compacts were compressed at a solid fraction of 0.80 for both powder and bead mixtures. An additional set of bead compacts were made at a solid fraction of 0.87. The thickness of the compacts was measured in the post-ejection stage to investigate their expansion behavior. The tensile strength with and without a stress concentrator and the dynamic indentation hardness of the compacts were determined. The brittle fracture index (BFI) and bonding index (BI) values were also calculated. The microstructure of the beads and compacts were investigated using scanning electron microscopy to observe the bonding phenomena. The results showed that the compacts made from beads underwent different compaction/consolidation behaviors than the powders of the same lactose/MCC compositions. For powdered compacts, the tensile strength with or without a stress concentrator increased with increasing MCC content while the compacts made from beads showed the opposite trend. However, this trend was not seen in the indentation hardness test. The resulting BFI values were all low due to the plastic nature of the materials selected. The BI values of the bead and powder compacts also exhibited opposite tendencies and reflected the divergent mechanical properties of the materials presented in granulated and powdered forms. Microstructure studies revealed the bonding states between the beads in the compacts. Discrepancies in mechanical properties were related to the compressibility, compactibility, and porosities of the excipients studied.     

钴铁氧体纳米管阵列制备及其磁学性能(英文)

为了研究一维钴铁氧体纳米管阵列的磁学性质,应用氧化铝模板具有的约束作用和毛细管作用,结合溶胶凝胶技术合成了钴铁氧体纳米管阵列.在140℃条件下,通过包含Fe(AO)3和Co(AO)2(物质的量之比为2∶1)的柠檬酸和乙二醇混合溶液(物质的量之比为1∶4)酯化反应得到溶胶.将氧化铝模板浸入溶胶几次后取出,取出充满溶胶的氧化铝模板,在大气气氛中,以0.6℃/min～5℃/min的升温速度将样品由室温升温至500℃,保温8 h.结果表明,在控制Fe3+离子浓度的条件下也可以合成钴铁氧体纳米线(Fe3+离子浓度大于1 mol/L)和"竹节"型纳米管(Fe3+离子浓度介于0.5 mol/L～1.0 mol/L),但重点进行了其纳米管阵列(Fe3+离子浓度小于0.5 mol/L)合成和磁学性能测试.透射电子显微镜(TEM)、高分辨电镜(HRTEM)的观察以及粉末X光衍射(XRD)测试结果表明纳米管组成为多晶结构.纳米管的直径取决于氧化铝模板的孔径,大约为200 nm,其长度约几个微米.应用样品振动磁强计对样品磁性进行了表征,结果表明纳米管阵列未表现出方向特性,矫顽力随着升温速率的降低而升高,在0.6℃/min的升温速率时,矫顽力达到最高的1 445 kOe,简单讨论了其形成原因.     

Thermophysical Properties of Mixtures of Tetrahydropyran with Chlorobutanes

Densities and absolute viscosities for the binary mixtures containing tetrahydropyran and isomeric chlorobutanes have been determined at 298.15 and 313.15 K at atmospheric pressure. From the densities, excess molar volumes were calculated. On the other hand, excess volumes and absolute viscosities have been correlated using the Peng–Robinson–Stryjek–Vera (PRSV) equation of state and the Lee model, respectively.     

Habit Modifications of Nitrofurantion Crystallized from Formic Acid Mixtures

The crystal size and the length to width ratio of Nitrofurantoin, an anti-bacterial urinary tract drug, can be controlled using an appropriate mixture of solvents and suitable crystallization conditions.

Some solvents will form undesirable complexes with the drug (INF) while with others no crystal structure modification or complexation was detected (HCO₂H).

The length (y) to width (x) ratio of the Nitrofurantoin varies from 2.5 to 1.5 when crystallized from pure formic acid or in a mixture with water or ethanol.

The y/x values correspond to the solvent interactions and super saturation (S).

The crystal growth regularity is ascribed to the solvent power and thus when more regular crystals will precipitate bioavailability and solubilization of the drug will increase. Best results were obtained when mixture of formic acid-ethanol solution was used as crystallization media yielding large tabular crystals.     

Thermodynamic and Acoustic Properties of Mixtures of Dibromomethane + Heptane

Densities and speeds of ultrasound in binary mixtures of dibromomethane with heptane have been measured within the temperature range from 288.15 K to 318.15 K. From the experimental data, the thermodynamic excess volume, molar isobaric expansion, molar isentropic compression, and ultrasonic speed were calculated. The excess volume and excess isentropic compression have opposite signs, whereas the excess isobaric expansion is an S-shaped function of the mole fraction. An explanation was suggested to account for the excesses in terms of intermolecular interactions. It involved energetic and steric factors. Moreover, it was shown that the positive excess sound speed results almost entirely from the negative excess compression.     

HFCs混合制冷剂热力性质的研究

为了利用PR方程和Huron-Vidal混合规则对三元混合制冷剂的热力性质进行精确计算,通过对10组二元HFCs混合制冷剂的汽液相平衡实验数据进行热力学关联,得出了相应的NRTL模型参数,由优选得到的过量Gibbs自由能NRTL模型的相互作用系数预测了构成R407C和R404A的三元混合制冷剂R32／R125／R134a以及R125／R143a／R134a的汽液相平衡,结果表明,泡点压力实验值和计算值的算术平均相对偏差小于0．42％,各组分的汽相组成实验值和计算值基本吻合。最后还应用相关热力性质分别对R32／R125和R407C进行了理论制冷循环分析计算并和其他模型的计算结果进行了比较。     

Thermodynamic and Transport Properties of Binary Mixtures Containing 1,3-Dioxolane

This paper reports density and viscosity measurements for the binary mixtures of cyclopentane or cyclohexane or benzene with 1,3-dioxolane at 283.15, 298.15, and 313.15 K. From the experimental data, excess volumes and excess viscosities were calculated and the results were fitted to a Redlich–Kister-type equation. The results are discussed in terms of molecular interactions. The Prigogine–Flory–Patterson and Blomfield–Dewan theories were used to analyze the results at 298.15 K.