Three‐dimensional high‐conductivity trees for volumetric cooling

Here, we show how the cooling performance of a volumetrically heated solid can be increased by embedding high‐conductivity tree‐shaped designs in it. The volume fraction occupied by the high‐conductivity material is fixed. Embedding the high‐conductivity material as trees in the solid decreases the maximum temperature more than three times compared with distributing the high‐conductivity material uniformly throughout the solid. The maximum temperature decreases as the number of the bifurcation levels and the volume fraction of the highly conductive material increase. The thermal resistance of the cube is the lowest when the diameter ratio of the mother and daughter branches at each pairing junction is 2. Changing from T‐shaped to Y‐shaped designs and from two‐dimensional to three‐dimensional designs decrease the maximum and the volume averaged temperatures. The peak temperature is the lowest in three‐dimensional and Y‐shaped designs. This paper shows that the peak temperature of the heated solid can be decreased by only varying the shape of the high‐conductivity tree embedded in it. Copyright © 2014 John Wiley & Sons, Ltd.     

Correlations of in situ modulus of deformation with elastic modulus of intact core specimens and RMR values of andesitic rocks: a case study of the İzmir subway line

Bulletin of Engineering Geology and the Environment - The main purpose of this paper is to obtain the rock mass rating (RMR) from different methods considering either the elastic modulus of intact...     

Formulation studies for mirtazapine orally disintegrating tablets

Abstract

Objective: Orally disintegrating tablets (ODTs) recently have gained much attention to fulfill the needs for pediatric, geriatric, and psychiatric patients with dysphagia. Aim of this study was to develop new ODT formulations containing mirtazapine, an antidepressant drug molecule having bitter taste, by using simple and inexpensive preparation methods such as coacervation, direct compression and to compare their characteristics with those of reference product (Remereon SolTab).

Materials and methods: Coacervation method was chosen for taste masking of mirtazapine. In vitro characterization studies such as diameter and thickness, weight variation, tablet hardness, tablet friability and disintegration time were performed on tablet formulations. Wetting time and in vitro dissolution tests of developed ODTs also studied using 900?mL 0.1?N HCl medium, 900?mL pH 6.8 phosphate buffer or 900?mL pH 4.5 acetate buffer at 37?±?0.2?°C as dissolution medium.

Results: Ratio of Eudragit® E-100 was chosen as 6% (w/w) since the dissolution profile of A1 (6% Eudragit® E-100) was found closer to the reference product than A2 (4% Eudragit® E-100) and A3 (8% Eudragit® E-100). Group D, E and F formulations were presented better results in terms of disintegration time. Dissolution results indicated that Group E and F formulations showed optimum properties in all three dissolution media.

Discussion: Formulations D1, D4, D5, E3, E4, F1 and F5 found suitable as ODT formulations due to their favorable disintegration times and dissolution profiles.

Conclusion: Developed mirtazapine ODTs were found promising in terms of showing the similar characteristics to the original formulation.     

Novel mixed ligand complexes of Co(II), Ni(II), Cu(II), and Zn(II) with 1,10-phenanthroline and acesulfame. Synthesis,structural analysis and hydrogen adsorption study

Four novel metal organic framework (MOF) structures containing acesulfame (ace) and 1,10-phenanthroline (phen) ligands of Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal cations were synthesized. The crystal structure analysis of three compounds (1, 2, and 3) was also performed. The structural formula for complex 4 is proposed based on spectroscopic and thermal analysis data. It has been determined that structures 1, 2, and 4 are in a distorted octahedral geometry. It has been suggested that the charge balance of the coordination sphere with 2+ is provided by two monoanionic ace ligands located outside the coordination sphere as counter-ion. In structure 3, there are two Cu^II metal cations, two phen ligands coordinated as bidentate to each metal cation and ace ligand that provides monoanionic-monodentate coordination. The Cu²⁺ cation has distorted bipyramidal geometry. The maximum hydrogen gas adsorption has been found 1.4575 mL/g (0.046 wt%) for the Ni complex.     

Proximate composition and fatty acid profiles of common pufferfish species in the Mediterranean Sea

The effects of season and gender on the proximate composition and fatty acid profiles of the most widespread pufferfish species in the Mediterranean Sea (Lagocephalus sceleratus, Lagocephalus spadiceus, Lagocephalus suezensis and Torquigener flavimaculosus) caught in Mersin Bay, in the north-eastern Mediterranean during four seasons were investigated. The results showed that the crude protein, lipid, moisture and ash level in pufferfish were in the range of 18.7%–21.7%, 0.61%–1.93%, 76.1%–78.6% and 1.08%–1.87%, respectively. All of the pufferfish had significant levels of polyunsaturated fatty acid (PUFA). However, the consumption of L. sceleratus, L. suezensis and T. flavimaculosus may be risky due to the possibility of having tetrodotoxin in their muscles. Nevertheless, L. spadiceus is a pufferfish species that is popularly consumed in East Asian countries, and is of nutritional interest and commercial potential in the Mediterranean region as well so its proximate composition and fatty acid profile are of interest.     

Doping of Nb to the Ba and Cu Sites in the Y0.6Gd0.4Ba2Cu3O7−δ

Polycrystalline samples of Y_0.6Gd_0.4Ba_2?x Nb _x Cu₃O_7?δ and Y_0.6Gd_0.4Ba₂Cu_3?x Nb _x O_7?δ with different Nb contents (x=0.025, 0.075, 0.125, 0.175 and 0.225) were prepared using the solid state reaction method. Structural and electrical properties of new compounds were investigated with optical microscope, scanning electron microscopy (SEM), X-ray diffraction (XRD), Four Point Probe (FPP). The results indicated that Nb constituted YBa₂NbO₆ structure instead of substituting to the Y_0.6Gd_0.4Ba₂Cu₃O_7?δ structure. YBa₂NbO₆ structures gathered between grains. Transition temperature did not change significantly, but critical current (J _c) values decreased with increase of Nb concentration. The underlying reason is that the oxygen concentration of compounds remained unchanged due to Gd; thus, T _c values did not change significantly.     

Kinetic Investigation of Reaction Between Mineral Ulexite and Citric Acid

In this study, the dissolution kinetics of ulexite, a sodium-calcium-borate hydrate (Na₂O·2CaO·5B₂O₃·16H₂O) in citric acid solutions was investigated in a batch reactor. The rate of dissolution can be expressed according to surface chemical reaction controlling with changing fluid reactant concentration. The activation energy of the process was found to be 39.4 kJ/mol.