An Investigation for Ground State Features of Some Structural Fusion Materials

Environmental concerns associated with fossil fuels are creating increased interest in alternative non-fossil energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. When considered in all energy systems, the requirements for performance of structural materials in a fusion reactor first wall, blanket or diverter, are arguably more demanding or difficult than for other energy system. The development of fusion materials for the safety of fusion power systems and understanding nuclear properties is important. In this paper, ground state properties for some structural fusion materials as ²⁷Al, ⁵¹V, ⁵²Cr, ⁵⁵Mn, and ⁵⁶Fe are investigated using Skyrme–Hartree–Fock method. The obtained results have been discussed and compared with the available experimental data.     

The Study of (<Emphasis Type="Italic">n,d</Emphasis>) Reaction Cross Sections for Some Medium Weight Targets up to 30 MeV

In this study, neutron incident reaction cross sections for some medium target nuclei ( ⁴⁴ Ca, ⁶⁵ Cu, ⁵⁴ Fe, ⁵⁶ Fe, ⁵⁷ Fe, ⁵⁸ Ni, ⁶⁰ Ni and ⁶⁷ Zn) have been investigated for the (n,d) reaction cross sections. These new calculations on the excitation functions of ⁴⁴ Ca(n,d) ⁴³ K, ⁶⁵ Cu(n,d) ⁴⁴ Ni, ⁵⁴ Fe(n,d) ⁵³ Mn, ⁵⁶ Fe(n,d) ⁵⁵ Mn, ⁵⁷ Fe(n,d) ⁵⁶ Mn, ⁵⁸ Ni(n,d) ⁵⁷ Co, ⁶⁰ Ni(n,d) ⁵⁹ Co and ⁶⁷ Zn(n,d) ⁶⁶ Cu reactions have been carried out up to 30 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The PEQ calculations involve the new evaluated the Geometry Dependent Hybrid model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. By using the new cross sections formulae for (n,d) reactions developed by Aydin et al., the obtained results have been discussed and compared with the available experimental data taken from EXFOR database.     

Viscoelastic and Processing Effects on the Fiber-Matrix Interphase Strength. Part I. The Effects of Loading Rate,Test Temperature,Fiber Sizing and Global Strain Level

The effects of loading rate, fiber sizing, test temperature and global strain level on the adhesion strength between carbon fibers and a thermosetting epoxy (Epon 815) are studied using the single fiber fragmentation test procedure. Analytical methodology describing the viscoelastic behavior observed is also presented. The possibility of rate-temperature-interphase thickness superposition for the interfacial strength function is illustrated based on the analytical models discussed. Experimental data are discussed using Weibull statistics and also presented in the form of percent relative frequency histograms for the fiber fragments in a collective fashion. The use of histograms allows for interpretation of the skewness in the data population.     

Carbon fiber-polyaniline composites: Kinetics of electrodeposition of polyaniline onto carbon fibers by cyclic voltammetry

Homogeneous and uniform coatings of polyaniline were successfully deposited on carbon fibers by an aqueous electrodeposition technique using p-toluene sulfonic acid as the electrolyte. Electrochemical deposition of aniline was carried out by cyclic voltammetry in the potential range of ?0.2 V to 1.0 V versus saturated calomel electrode (SCE). The electrochemical deposition parameters such as the number of cycles, scan rate (SR), initial monomer ([M]), and electrolyte concentration ([E]) were systematically varied. The amount of composite coatings on carbon fibers was dependent on the electrochemical deposition parameters. From a weight gain analysis, the rate of the reactions (R p ) was calculated. As the aniline concentration was increased up to 0.35 M and electrolyte concentration up to 0.5 M, the deposition rate also increased, whereas an increase in scan rate decreased the deposition rate. Kinetic analysis showed that the rate equation for the p-toluene sulfonic acid system is R p ∝SR ?1.25 [M] 0.73 [E] 0.95 . IR spectra also showed an increase in the deposition of polyaniline coatings on carbon fibers with a decrease in the scan rate and an increase in both monomer and electrolyte concentration. The ratio of two oxidation states of polyaniline obtained during electrodeposition, namely emeraldine and pernigraniline, can be varied by changing the electrochemical deposition parameters.     

Effect of protrusion at the ends of bondline in single lap joints under tension and bending

In this work, elasto-plastic stress analysis of single lap joints with and without protrusion in adhesive bondline subjected to tension and bending was carried out using 2D non-linear finite element analysis and confirmed experimentally. AA 2024-T3 aluminum adherends were bonded with SBT 9244 film adhesive. The protrusion was obtained by extending the adhesive film by 2?mm from the overlap length at both overlap ends. Three different adherend thicknesses and overlap lengths for each loading and bondline type were used. The joints with and without protrusion, for comparison, were loaded with the same load for each adherend thickness and overlap length. Finally, it was observed that the protrusion reduces the strength in the joint under tension, while the protrusion increases the strength in the joint under bending.     

Calculation of 14–15 MeV (<Emphasis Type="Italic">n,d</Emphasis>) Reaction Cross Sections Using Newly Evaluated Empirical and Semi-empirical Systematics

In this study, we have investigated the asymmetry term effect for the (n, d) reaction cross sections at 14–15 neutron incident energy. It has been discussed the odd–even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross section formulae developed by Tel et al. for (n, d) reactions. We have determined different parameter groups by the classification of nuclei into even–even, even–odd and odd–even for (n, d) reactions cross sections. The obtained empirical and semi-empirical formulae by fitting two parameters for (n, d) reactions were given. By using the new cross sections formulae for (n, d) reactions the obtained results have been discussed and compared with the available experimental data.     

Analysis of thermal response of a food self-heating system

This paper presents a distributed model of heat transfer in a self-heating unit for group meals and its numerical simulation. A magnesium alloy and water exothermic reaction provides the necessary energy. The resulting governing equations of chemical reaction and heat conduction that depicts the heater performance were solved to develop an approximate analytical solution, to which experimental data found from literature were compared and curve fitted. Then, a model of a complete food-heating unit for group meals, which include a stack of four sets of food tray, heating tray, and heater sandwiched between them, as well as the cardboard container, was developed. The governing equations for heat conduction in the complete model were solved. The response in thermal performance of the heating system to the parameters that influence heating profiles of the heater such as decay constant and heat generation capacity were studied. The results show that the system thermal performance is most significantly affected by heat generation and a proper combination of heaters with different heat generation capacity can improve temperature uniformity between food trays. The results are useful for designing and optimizing self-heating multi-food tray units.     

Separation,preconcentration and inductively coupled plasma-mass spectrometric (ICP-MS) determination of thorium(IV), titanium(IV), iron(III), lead(II) and chromium(III) on 2-nitroso-1-naphthol impregnated MCI GEL CHP20P resin

A simple and effective method is presented for the separation and preconcentration of Th(IV), Ti(IV), Fe(III), Pb(II) and Cr(III) by solid phase extraction on 2-nitroso-1-naphthol impregnated MCI GEL CHP20P resin prior to their inductively coupled plasma-mass spectrometric determinations. The influence of analytical parameters including pH of the aqueous solution, flow rates of sample and eluent solutions and sample volume on the quantitative recoveries of analyte ions was investigated. Matrix effects caused by the presence of alkali, earth alkali and some metal ions in the analyzed solutions were investigated. The presented solid phase extraction method was applied to BCR-144R Sewage Sludge (domestic origin), BCR-141R Calcareous Loam Soil, NIST 1568a Rice Flour and NIST 1577b Bovine Liver certified reference materials (CRMs) for the determination of analyte ions and the results were in good agreement with the certified values. The separation procedure presented was also applied to the various natural water samples collected from Turkey with satisfactory results.     

A general model for the permeability of fibrous porous media based on fluid flow simulations using the lattice Boltzmann method

Fluid flow analyses for porous media are of great importance in a wide range of industrial applications including, but not limited to, resin transfer moulding, filter analysis, transport of underground water and pollutants, and hydrocarbon recovery. Permeability is perhaps the most important property that characterizes porous media; however, its determination for different types of porous media is challenging due its complex dependence on the pore-level structure of the media. In the present work, fluid flow in three-dimensional random fibrous media is simulated using the lattice Boltzmann method. We determine the permeability of the medium using the Darcy law across a wide range of void fractions (0.08 ? ? ? 0.99) and find that the values for the permeability that we obtain are consistent with available experimental data. We use our numerical data to develop a semi-empirical constitutive model for the permeability of fibrous media as a function of their porosity and of the fibre diameter. The model, which is underpinned by the theoretical analysis of flow through cylinder arrays presented by [Gebart BR. Permeability of unidirectional reinforcements for RTM. J Compos Mater 1992; 26(8): 1100–33], gives an excellent fit to these data across the range of ?. We perform further simulations to determine the impact of the curvature and aspect ratio of the fibres on the permeability. We find that curvature has a negligible effect, and that aspect ratio is only important for fibres with aspect ratio smaller than 6:1, in which case the permeability increases with increasing aspect ratio. Finally, we calculate the permeability tensor for the fibrous media studied and confirm numerically that, for an isotropic medium, the permeability tensor reduces to a scalar value.     

Thulium hydroxide: a new coprecipitant for speciation of chromium in natural water samples

A coprecipitation procedure has been established for chromium speciation in natural water samples. The procedure is based on the coprecipitation of Cr(III) on thulium hydroxide precipitate. After reduction of Cr(VI) to Cr(III) by using potassium iodide, the presented method was applied to the determination of the total chromium. The level of Cr(VI) is calculated by difference of total chromium and Cr(III) levels. The procedure was optimized for some analytical parameters including pH, sample volume, matrix effects, etc. The detection limits based on 3sigma criterion were 0.87 microg L(-1) for Cr(III) and 1.18 microg L(-1) for Cr(VI). The procedure presented was validated by the analysis of BCR-144R Sewage Sludge (domestic origin). The presented method was applied for the speciation of chromium in environmental sample with satisfactory results (recoveries>95%, R.S.D.s<10%).