A New Algorithm for Estimating Three-Phase Relative Permeability from Unsteady-State Core Experiments

We present a new history matching method based on a Genetic Algorithm to estimate three-phase k _r (relative permeability) from unsteady-state coreflood experiments. In this method, relative permeabilities (k _r) are represented by quadratic B-Spline functions. Adjustable coefficients in k _r functions are changed in an iterative process to minimize an objective function. The objective function is defined as the difference between the measures and simulated values of the pressure drop across the core and fluids recovery during the experiment. One of the main features of this approach is that water and gas relative permeabilities (k _rw and k _rg) are assumed to be functions of two independent saturations as opposed to most of the existing empirical k _r models in which k _rw and k _rg are assumed to be only dependent of their own saturations. Another important aspect of this algorithm is that it considers inequality constrains to ensure that physically acceptable k _r curves are maintained throughout the iterative optimization process. A three-phase coreflood simulator has been developed based on this methodology that generates best k _r values by matching experimental data. The integrity of the developed software was first successfully verified by using two sets of experimental three-phase k _r data published in the literature. Then, the results of some three-phase coreflood experiments carried out in our laboratory were used to obtain three-phase k _r curves by this approach.     

Multiple hydrogen bondings in a platinum complex

An unprecedented example of a platinum(II) complex with simultaneous formation of intermolecular NH···I-Pt and CH···I-Pt H-bondings (with neighboring platinum center) and an intramolecular CH···Pt hydrogen bonding in solid state is described. There are indications showing that the complex in solution probably forms a different kind of H-bonding type interaction.     

Free-edge stress analysis of general composite laminates under extension, torsion and bending

In this study, based on the reduced form of elasticity displacement field for a long laminate, an analytical method is established to exactly obtain the interlaminar stresses near the free edges of generally laminated composite plates subjects to extension, torsion, and bending. The constant parameters being in the displacement field, which describe the global deformation of a laminate, are appropriately calculated by using the improved first-order shear deformation theory. Reddy’s layerwise theory is subsequently employed for analytical and numerical examinations of the boundary layer stresses within arbitrary laminated composite plates. Various numerical results are developed for the interlaminar normal and shear stresses along the interfaces and through the thickness of laminates near the free edges. Finally the effects of end conditions of laminates and geometric parameters on the boundary-layer stress are studied.     

Aluminum-27 NMR Investigations of Aqueous and Methanolic Aluminosilicate Solutions

Aluminum-27 NMR spectroscopy was used to characterize aqueous and methanolic alkaline solutions of tetramethylammonium (TMA) aluminosilicates. Aluminosilicate solutions have been prepared with different concentrations of silicon [0.577–1.24% (w/w)], aluminum [0.0022–0.239% (w/w)], methanol [0.0–0.70% (w/w)] and H₂O [0.23–90% (w/w)]. All solutions contain the same ratio of Si/TMA = 1 and Si/Al molar ratios between 0.5 and 25.²⁷Al NMR spectra of TMA aluminosilicate solutions are characterized by a variety of aluminosilicate species such as q¹(Al1OSi), q²(Al2OSi), q³(Al3OSi) and q⁴(Al4OSi). Aluminum-27 NMR spectra of TMA aluminosilicate solutions indicate that considerable changes occurred by changing the Si/Al ratio. The distribution of aluminosilicate species was affected by the presence of the methanol and the method of mixing the silicate and aluminosilicate solutions. A methanolic aluminosilicate solution needs about twice the time required for an aqueous aluminosilicate solution to reach a steady state, i.e., the latter takes 36 h to reach steady state. Results with the same concentration of silicon and aluminum show that the formation and distribution of aluminosilicate species are strongly dependent on the solvent comprising the silicate and aluminate solutions.     

Free resolutions of parameter ideals for some rings with finite local cohomology

Let be a -dimensional local ring, with maximal ideal , containing a field and let be a system of parameters for . If and the local cohomology module is finitely generated, then there exists an integer such that the modules have the same Betti numbers, for all .

     

Voltammetric Determination of Isoproterenol using a Graphene Oxide Nano Sheets Paste Electrode

3-(4'-Amino-3'-hydroxy-biphenyl-4-yl)-acrylic acid, was synthesized and used to construct a modified-graphene oxide nano sheets paste electrode. The electro-oxidation of isoproterenol at the surface of the modified electrode was studied using cyclic voltammetry, chronoamperometry, and square wave voltammetry. Under the optimized conditions, the square wave voltammetric peak currents of isoproterenol increased linearly with isoproterenol concentrations in the range of 2.5 × 10^–8 to 2.0 × 10^–5 M and detection limit of 12 nM was obtained for isoproterenol. Finally this modified electrode was used for determination of isoproterenol in some real samples.     

Preparation of 99mTc-MIBI complex under ultrasound irradiation

The (37MBq) 99mTc-MIBI complex samples were prepared due to ultrasound irradiation technique or boiled water bath method as a standard method. The qualitative and quantitative studies have been performed. The accumulation of 99mTc-MIBI complexes prepared by two above mentioned modalities were approximately 3 ± 0.1 % in the rats’ heart. The ultrasound irradiation technique is recommended to prepared 99mTc-MIBI complex in efficiently amount. Our approach can potentially reduce medical risk to the patient by avoiding any delay in acute therapy particularly for myocardial infarction patients.