Analysis of the Thermal Stability of Very Thin Surface Layers of Corrosion Inhibitors by Time-of-Flight Secondary Ion Mass Spectrometry

The powerful nature of the secondary ion mass spectrometry (SIMS) technique was explored in order to analyse very thin surface layers that were self-assembled on steel material from acidic solution. These surface layers are adsorbed corrosion inhibitors. The SIMS technique proved useful to characterise the molecular structure and homogeneity of thin surface layers in the nanometre range of specific analytes on the metallic substrate. Using SIMS, the thermal stability of these layers was further investigated and the desorption energy at a certain temperature was determined, where special attention was devoted to the method’s static limit. In order to compare, and for certain cases emphasise, the benefits gained by using SIMS in such surface analysis compared with the X-ray photoelectron spectroscopy (XPS) method, the same samples were also analysed by means of the latter. XPS is usually considered to be the most powerful analytical tool in surface analysis studies, but, as shown herein, it has certain limitations compared to SIMS. Finally, the surface topography was investigated by employing atomic force microscopy (AFM) in order to carry out a comprehensive surface analysis.

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Transglobal Evidentialism-Reliabilism

We propose an approach to epistemic justification that incorporates elements of both reliabilism and evidentialism, while also transforming these elements in significant ways. After briefly describing and motivating the non-standard version of reliabilism that Henderson and Horgan call “transglobal” reliabilism, we harness some of Henderson and Horgan’s conceptual machinery to provide a non-reliabilist account of propositional justification (i.e., evidential support). We then invoke this account, together with the notion of a transglobally reliable belief-forming process, to give an account of doxastic justification.

Concentrating rotaviruses from water samples using monolithic chromatographic supports

Rotaviruses are the leading cause of diarrhoea in infants around the globe and, under certain conditions they can be present in drinking water sources and systems. Ingestion of 10–100 viral particles is enough to cause disease, emphasizing the need for sensitive diagnostic methods. In this study we have optimized the concentration of rotavirus particles using methacrylate monolithic chromatographic supports. Different surface chemistries and mobile phases were tested. A strong anion exchanger and phosphate buffer (pH 7) resulted in the highest recoveries after elution of the bound virus with 1 M NaCl. Using this approach, rotavirus particles spiked in 1 l volumes of tap or river water were efficiently concentrated. The developed concentration method in combination with a real time quantitative polymerase chain reaction assay detected rotavirus concentrations as low as 100 rotavirus particles/ml.     

Energetic basis of human telomeric DNA folding into G-quadruplex structures

Recent theoretical studies performed on the folding/unfolding mechanism of the model telomeric human DNA, 5'-AGGGTTAGGGTTAGGGTTAGGG-3' (Tel22), have indicated that in the presence of K(+) ions Tel22 folds into two hybrid G-quadruplex structures characterized by one double and two reversal TTA loops arranged in a different way. They predicted a new unfolding pathway from the initial mixture of hybrid G-quadruplexes via the corresponding intermediate triplex structures into the final, fully unfolded state. Significantly, no experimental evidence supporting the suggested pathway has been reported. In the current work, we performed a comprehensive global thermodynamic analysis of calorimetric (DSC, ITC) and spectroscopic (CD) data obtained on monitoring the folding/unfolding of Tel22 induced by changes of temperature and K(+) concentration. We show that unfolding of Tel22 may be described as a monomolecular equilibrium three-state process that involves thermodynamically distinguishable folded (F), intermediate (I), and unfolded (U) state. Considering that calorimetric methods cannot distinguish between energetically similar G-quadruplex or triplex conformations predicted by the theoretical model one can conclude that our results represent the first experimental support of the suggested unfolding/folding mechanism of Tel22. This conclusion is confirmed by the fact that the estimated number of K(+) ions released upon each unfolding step in our thermodynamic model agrees well with the corresponding values predicted by the theoretical model and that the observed changes in enthalpy, entropy, and heat capacity accompanying the F → I and I → U transitions can be reasonably explained only if the intermediate state I is considered to be a triplex structural conformation.     

Complete dynamical analysis of a neocortical network model

Nonlinear Dynamics - The brain is a complex system consisting of a large number of interacting neurons. Recently, a simple nonlinear biological model has been proposed for the up and down state...     

MnOx Nanoparticles Supported on a New Mesostructured Silicate with Textural Porosity

A two‐step synthesis of a novel mesostructured silicate, KIL‐2, and its manganese‐containing analogue, Mn/KIL‐2, has been developed. KIL‐2 possesses interparticle mesopores with pore dimensions between 5 and 60 nm and a surface area of 448 m². The mesopores are formed by the aggregation of silica nanoparticles, which creates a network with interparticle voids. The particle size and the pore diameters depend on the temperature of the ageing step (first step) and on the solvothermal treatment in ethanol (second step), respectively. Mn/KIL‐2 contains octahedrally coordinated Mn³⁺ (80 %) and tetrahedrally coordinated Mn²⁺ (20 %) ions. Mn³⁺ ions are present in the extra‐framework MnO_x nanoparticles with typical dimensions of 2 nm, which are homogeneously distributed throughout the material. Mn²⁺ ions occur as isolated manganese framework sites. The material is also able to retain its structure characteristics after the hydrothermal treatment in boiling water. Because of its non‐toxic nature and cost‐effective synthesis, Mn/KIL‐2 thus exhibits properties that are needed for an environment‐friendly catalyst.     

Core and Ancillary Epistemic Virtues

We argue, primarily by appeal to phenomenological considerations related to the experiential aspects of agency, that belief fixation is broadly agentive; although it is rarely (if ever) voluntary, nonetheless, it is phenomenologically agentive because of its significant phenomenological similarities to voluntary-agency experience. An important consequence is that epistemic rationality, as a central feature of belief fixation, is an agentive notion. This enables us to introduce and develop a distinction between core and ancillary epistemic virtues. Core epistemic virtues involve several inter-related kinds of epistemic rationality in belief fixation. Other “habits of mind” pertinent to belief fixation constitute ancillary epistemic virtues. Finally, we discuss the relationship between both kinds of virtues, offering a unified account of epistemic virtuousness.     

Weakly coupled analysis of a blade in multiphase mixing vessel

Two or more physical systems frequently interact with each other, where the independent solution of one system is impossible without a simultaneous solution of the others. An obvious coupled system is that of a dynamic fluid-structure interaction. [8] In this paper a computational analysis of the fluid-structure interaction in a mixing vessel is presented. In mixing vessels the fluid can have a significant influence on the deformation of blades during mixing, depending on speed of mixing blades and fluid viscosity. For this purpose a computational weakly coupled analysis has been performed to determine the multiphase fluid influences on the mixing vessel structure. The multiphase fluid field in the mixing vessel was first analyzed with the computational fluid dynamics (CFD) code CFX. The results in the form of pressure were then applied to the blade model, which was the analysed with the structural code MSC.visualNastran forWindows, which is based on the finite element method (FEM). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Experimental investigation of the interaction of two flows on the axial fan hollow blades by flow visualization and hot-wire anemometry

Experimental investigation of the interaction of internal flow with external flow around hollow airfoil NACA series in a low-speed wind tunnel was conducted and is presented in the paper. The region near the trailing edge of the hollow airfoil was studied in detail and measurements of velocity and turbulence intensities were performed with hot-wire anemometry. Determination of flow structure on the hollow airfoil was performed with computer-aided visualization. It can be concluded from the measurement analysis that higher values of velocities, lower turbulence intensities and a significant decrease of circulation effects on the suction side of the hollow blade were achieved, due to the introduction of internal flow. The results obtained on the hollow airfoil were applied on the rotating axial fan. Influence of the internal flow of the hollow blade on the flow field of the axial fan was studied. With the introduction of the internal flow a reduction of circulation effects on the fan hollow blade was achieved. Aerodynamic characteristic of the axial fan reached higher degree of total pressure difference and normalized efficiency through the entire fan working conditions.