Advanced TALSPEAK Separations Using a Malonate Buffer System

The extraction behavior of lanthanides and americium has been evaluated under Advanced TALSPEAK (Trivalent Actinide Lanthanide Separation by Phosphorus-reagent Extraction from Aqueous Komplexes) conditions using malonic acid as the aqueous buffering agent. The extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) was used as an organic phase liquid cation exchanger in n-dodecane diluent, while N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA) served as a selective aqueous holdback reagent. Extractions conducted from malonate media exhibit a pH profile that flattens as the concentration of malonate is increased up to 1.0 M malonate. This relatively flat extraction behavior from pH 2.5–4.0 is reminiscent of previous studies on Advanced TALSPEAK in lactate media. The extraction kinetics with other carboxylic acid buffers as well as the effects of varying HEDTA, HEH[EHP], and malonate concentration are compared.     

Cryogenic grinding of electrospun poly-ε-caprolactone mesh submerged in liquid media

In this paper, the treatment of poly-ε-caprolactone (PCL) nano/micro-mesh system by cryogenic grinding and subsequent characterization of obtained product is described. The PCL nano/micro-mesh layer submerged in appropriate liquid was cryogenically ground and obtained particles were characterized employing mainly laser diffraction and scanning electron microscopy (SEM). In the ground sample, different types of particles (fibrous particles, fibrous fragments, agglomerates with and without an internal fibrous structure, lamellae and nanoparticles) were identified, described and quantified. Parameters of cryogenic grinding (weight of sample, type of liquid medium, and influence of sample storage) were optimized to maximize the yield of particles with desired features. The potential of the system for cell scaffolding was demonstrated by cultivation of 3T3 fibroblasts on the produced microparticles.     

Electronic energy levels of trivalent lanthanide ions in chalcogenide glasses: Case of Pr3+, Sm3+, and Dy3+

Praseodymium-, samarium-, and dysprosium-doped chalcogenide glasses from Ga–Ge–(Sb)–Se system were prepared. The Slater electrostatic F^k (k = 2,4,6), spin-orbit (ζ_4f), and configuration–interaction (α) parameters of Pr³⁺, Sm³⁺, and Dy³⁺ ions, calculated on the basis of transmittance spectra, were studied. The dependences of all mentioned parameters on the chemical composition of the glassy matrix are discussed.     

Depolymerization during nitroxide‐mediated oxidation of native cellulose

The kinetics and mechanism of depolymerization during nitroxide‐mediated oxidation of native cellulose has been studied under various conditions. The physical heterogeneity of the native cellulose and its complicated hypermolecular and supramolecular structure exerts a remarkable influence on the kinetics of oxidation and depolymerization. A strong influence of external tension applied on cellulose gauze reactivity during its oxidation has been proven, which is caused by its complicated hypermolecular structure. Celluloronic acids were obtained by the application of external tension during selective oxidation of native cellulose textiles. The cellouronic acids contained the higher amount of carboxyl groups but they also had a lower intrinsic viscosity, i.e., the average degree of polymerization (DP). The mathematical model—so‐called DP‐peeling off model—has been derived to describe the kinetics of cellulose depolymerization based on experimental data obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Project SPHINX spent hot fuel incinerator by neutron flux (the development of a new reactor concept with liquid fuel based on molten fluorides)

The SPHINX project is dealing with a solution of some principle problems of a very promising way of nuclear waste treatment, high level wastes from spent nuclear fuel in particular, by means of transmutation of radionuclides by use of a nuclear reactor with liquid fuel based on molten fluorides, which might be a subcritical system driven by a suitable neutron source. Its superiority lies also in the fact that it makes possible to utilize actinides contained, by others, in spent nuclear fuel and so to reach a positive energy effect.

The SPHINX project has been proposed by the consortium TRANSMUTATION being established by four leading nuclear research bodies in the Czech Republic (Nuclear Research Institute Rez plc, SKODA Nuclear Machinery plc in Pilsen, Nuclear Physics Institute of Academy of Sciences in Rez and Technical University in Praha) at the end of 1996 to which Technical University in Brno (specialized for a secondary circuit problems) has associated in the year 2000. The project has been supported by the Ministry of Industry and Trade of the Czech Republic, CEZ, a.s. (Czech Electricity Generating Company) and RAWRA (Radwaste Repository Authority).

The R&D program of the SPHINX project contains an experimental part, which serves for a verification of design inputs for designing a demonstration unit of a transmuter with liquid fuel based on molten fluorides. The current status of the experimental program performance has been focused upon the irradiation of samples of molten-salt systems as well as structural materials proposed for the blanket of the SPHINX transmuter in the field of high neutron flux of research reactors.

The main aims of this program called Irradiated Probes BLANKA are the following: (1) Experimental verification of long time behavior of transmuter blanket which contains molten fluoride salts as a fuel and coolant, (2) Validation of computational code system being developed for the computation of actinides concentration in long- term operation of the transmuter, and (3) Material research on behavior of materials in neutron and gamma fields, and materials interactions on high temperature conditions.

At present, two agreements on multinational cooperation in this field have been signed: One with European Commission and one with Russian Kurchatov Institute (joint experimental programs AMPULA containing fluorides of transuranium elements like Np, Pu, Am and Cm in irradiated samples and a joint development of the ISTAR code).     

Comparison of the total antioxidant status of Bohemian wines during the wine-making process

The total antioxidant status (TAS) of two white and two blue wine varieties from the ?ernoseky wine region (North Bohemia, Czech Republic) during the wine-making process was assessed by measurement with different radical scavenging assays: ABTS, DPPH and DMPD. Significant differences in the antioxidant activity between white and red wines were confirmed and changes of TAS during the wine production process were demonstrated. Moreover, differences were ascertained between individual varieties of red wine. No statistically significant relationship between the results provided by the ABTS and DPPH assays was found, obviously due to the fact that each phenolic substance in wine gives a different response to each specific radical used in the assay. The results obtained supported the assumption that variety plays a considerable role in TAS; the blue wine varieties showed a much higher TAS than did the white wines. The ABTS assay showed higher EQA (equivalents of ascorbic acid, mg/ml) values than the DPPH assay.     

Improved extrapolation method for the fatigue damage of bus structural steel under service loading

Journal of Mechanical Science and Technology - This paper shows a technical study and analysis of the fatigue damage assessment of bus structural steel under service loading. Two bus prototypes...     

Changing Landscapes,Changing Landscape's Story

Abstract

Visual surrogates have been widely used for solving environment related issues. Researchers now have concern over the validity of surrogates. Human perception is multi-modal (Wohlwill, 1976 Wohlwill, J. F. 1976. “Environmental aesthetics: the environment as a source of affect”. In Human Behavior and Environment: Advances in Theory and Research, Edited by: Altman, I. and Wohlwill, J. F. New York: Plenum Press. [Crossref] , [Google Scholar]; Ittelson, 1973 Ittelson W. Environment and Cognition Seminar Press New York 1973  [Google Scholar]) and motion is an essential aspect in the perceptual process (Gibson, 1979 Gibson, J. J. 1979. The Ecological Approach to Visual Perception, Boston, MA: Houghton Mifflin.  [Google Scholar]). Therefore, a surrogate has to be able to represent the dynamic elements in the environment and more realistically reflect human environmental experience. The purpose of this study was to examine the validity of videos and slides as visual surrogates for representing dynamic environment. The validity of the surrogates was verified by comparing subjects' perceptual responses to on-site and simulated situations. The perceptual assessments included emotional, cognitive, behavioural and preference responses. The results indicated that on-site participants' emotional responses and preferences are significantly stronger than those of video and slide viewers. In addition, on-site participants' and video viewers' cognitive and behavioural responses were significantly higher than those of slide viewers. Overall, the validity of videos and slides for representing waterscapes was not supported.     

Experimental analysis of irregularities of metallic surfaces generated by abrasive waterjet

Experimental study of the surface quality produced by abrasive waterjet (AWJ) on metallic materials has been performed. The surface roughness/waviness was quantitatively evaluated by using the contactless optical measurement. In order to characterize the cut surface qualities, a single-parameter criterion has been proposed. Based on root mean square (RMS) roughness evaluation of the worst cut surface zone, the dimensionless statistical parameter C can be calculated as a basic quantity for AWJ surface cut characterization. As it was approved, besides its dependency on depth of AWJ trace, the value of C-parameter for the specific material is noticeably related also to the traverse speed of the cutting head. Such a relationship can be potentially used for adjusting the cutting speed of the machining process.