Matrix–Fracture Transfer through Countercurrent Imbibition in Presence of Fracture Fluid Flow

Although a lot of research has been done in modeling the oil recovery from fractured reservoirs by countercurrent imbibition, less attention has been paid to the effect of the fracture fluid velocity upon the rate of oil recovery. Experiments are conducted to determine the effect of fracture flow rate upon countercurrent imbibition. A droplet detachment model is proposed to derive the effective water saturation in a thin boundary layer at the matrix–fracture interface. This effective boundary water saturation is a function of fluid properties, fluid velocity in the fracture and fracture width. For a highly water–wet porous medium, this model predicts an increase in the boundary water saturation with increase in fracture fluid velocity. The increase in boundary water saturation, in turn, increases the oil recovery rate from the matrix, which is consistent with the experimental results. The model also predicts that the oil recovery rate does not vary linearly with the boundary water saturation.     

Performance studies of electrolyte-supported solid oxide fuel cell with Ni–YSZ and Ni–TiO2–YSZ as anodes

Redox cycling of Ni-based anode induces cell degradation which limits the cell's lifetime during solid oxide fuel cell operation. In the present study, the redox testing of electrolyte-supported cells has been investigated with TiO₂-added NiO–YSZ anode matrix. Button cells were fabricated by die-pressing YSZ powder as electrolyte, and onto which NiO–YSZ or NiO–TiO₂–YSZ anode and LSM–YSZ composite cathode were painted. The electrochemical performance and stability have been evaluated by measuring current–voltage characteristics followed by impedance spectroscopy after each redox cycling. Anode matrices before and after cell operation have been characterized by X-ray diffraction (XRD), elemental dispersive X-ray (EDX), and scanning electron microscopy (SEM). During cell operation the peak power density decreases from 111 mW cm^?2 (239 mA cm^?2) to 84 mW cm^?2 (188 mA cm^?2) between 23 and 128 h with five redox cycles for cell having NiO–YSZ (40:60) anode. But for cell with NiO–TiO₂–YSZ (30:10:60), the anode peak power density was constant and stable around 85 mW cm^?2 (194 mA cm^?2) throughout the cell run of 130 h and five redox cycles. No loss in the open circuit voltage was observed. SEM and XRD studies of NiO–TiO₂–YSZ (30:10:60) anodes revealed formation of ZrTiO₄, which may be responsible for inhibition of Ni coarsening leading to stable cell performance.     

Large Magnetocaloric Effect,Moment, and Coercivity Enhancement after Coating Ni Nanoparticles with Ag

We observe a large magnetocaloric effect in monodisperse Ni and Ni_coreAg_shell nanoparticles in the superparamagnetic region. The organically passivated Ni nanospheres show a large magnetic entropy change of 0.9 J kg^?1 K for a 3 T magnetic field change. In comparison to the surfactant‐coated Ni nanoparticles, the Ni_coreAg_shell nanoparticles show an enhanced coercivity, magnetization, and magnetocaloric effect (1.3 kg K for a 3 T magnetic field change). The coercivity at 10 K increases from 360 Oe for Ni nanoparticles to nearly 610 Oe for Ni_coreAg_shell particles. This large enhancement is attributed to the enhanced inter‐particle interaction, which is mediated by the metallic shell, over the relatively weaker dipolar interaction in the surfactant‐coated Ni nanoparticles, and to modification of the surface spin structure.     

Organocatalytic Asymmetric Friedel–Crafts Reaction of Sesamol with Isatins: Access to Biologically Relevant 3‐Aryl‐3‐hydroxy‐2‐oxindoles

The Friedel–Crafts reaction of electron‐rich phenols with isatins was developed by employing bifunctional thiourea–tertiary amine organocatalysts. Cinchona alkaloid derived thiourea epiCDT‐ 3 a efficiently catalyzed the Friedel–Crafts‐type addition of phenols to isatin derivatives to provide 3‐aryl‐3‐hydroxy‐2‐oxindoles 7 and 9 in good yield (80–95 %) with good enantiomeric excess (83–94 %). Friedel–Crafts adduct 7 t was subjected to a copper(I)‐catalyzed azide–alkyne cycloaddition to obtain biologically important 3‐aryl‐3‐hydroxy‐2‐oxindole 11 in good enantiomeric excess and having a 1,2,3‐triazole moiety.     

Study of 10Be in the sediments from the Krossfjorden and Kongsfjorden Fjord System,Svalbard

The distribution of ¹⁰Be, as well as the major elements concentrations and the grain size in surface and core sediment samples, collected from Krossfjorden and Kongsfjorden, Svalbard have been studied for understanding the origin of ¹⁰Be and an estimation of its accumulation rate. The ¹⁰Be concentration in sediments varies between 0.90 × 10⁸ and 2.53 × 10⁸ atoms g^?1. Our results show that atmospherically produced ¹⁰Be dominates over terrigenous (in situ) sources of ¹⁰Be in the studied samples. The calculated ¹⁰Be accumulation rate varies from 3.1 × 10⁶ atoms cm^?2 year^?1 to 8.6 × 10⁶ atoms cm^?2 year^?1 which is higher than the accumulation rate observed in the deep sea sediment cores of the Arctic Ocean and the Norwegian Sea. The higher accumulation rate of ¹⁰Be is attributed to the higher influx of glacier melt water into the fjord system.     

Syntheses of Aromatic Aldehydes by Laccase of Pleurotus ostreatus MTCC-1801

Selective bioconversion of the aromatic methyl group to its aldehyde group is one of the best applications of the laccases. In the present communication, crude laccase, obtained from the liquid culture medium of the fungal strain Pleurotus ostreatus MTCC-1801, has been used for the selective bioconversion of toluene, 3-nitrotoluene, 4-nitrotoluene, 2-fluorotoluene, 4-fluorotoluene, 2-chlorotoluene, 3-chlorotoluene, 4-chlorotoluene, and 3,4-dimethoxytoluene to benzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, 2-fluorobenzaldehyde, 4-fluorobenzaldehyde, 2-chlorobenzaldehyde, 3-chlorobenzaldehyde, 4-chlorobenzaldehyde, and 3,4-dimethoxybenzaldehyde, respectively, in the presence of 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) as a mediator molecule. Time taken by these conversions was 1–2 h, and average yield of products was more than 93%.     

Liquid chromatography tandem mass spectrometry method for the quantitation of mycophenolate mofetil in human plasma: Application to a bioequivalence study and metabolite identification

We established a sensitive, selective, and rapid analytical method for the quantitation and pharmacokinetic investigation of mycophenolate mofetil in human plasma. To our knowledge, this is the first method that characterizes presence of mycophenolate mofetil glucuronide in clinical samples through tandem mass spectrometry detection and resolves mycophenolate mofetil from its glucuronide metabolite. Liquid chromatography coupled to tandem mass spectrometry detection in positive ion mode was selected to provide optimal selectivity and sensitivity. Due to the ionizable characteristics of the mycophenolate mofetil, a mixed‐mode cation‐exchange disposable extraction cartridge was prudently chosen. The chromatographic separation was achieved on Luna^® C18(2) (100×4.60 mm) column using mobile phase consisting of a mixture of 1±0.05 mM ammonium formate in water, titrated to pH 3.1±0.1 with formic acid, and methanol (20:80, v/v), at a flow rate of 0.7 mL/min. The detection was led at m/z ratios of 434.4→ 114.2 and 438.4→ 118.3, for mycophenolate mofetil and mycophenolate mofetil‐D4, respectively. The developed method was linear between 40.2–4986.0 pg/mL. All validation parameters were within the defined limits. The validated method was then successfully applied for the evaluation of bioequivalence parameters of mycophenolate mofetil after an oral administration of 500 mg mycophenolate mofetil tablet to healthy male Indian volunteers.     

Optimal normative policies for marketing of products with limited availability

We develop optimal normative policies for pricing and advertising of products with limited availability by including the traditional product diffusion parameters (Bass, 1969)–innovation and imitation, and the scarcity effects generated due to limited product availability (Swami and Khairnar, 2003). Using optimal control methodology, our pricing policy results suggest that a profit-maximizing firm gradually increases the price as the sales approach the product availability. The optimal normative advertising policy recommends gradually decreasing the expenditure on the awareness advertising and increasing the expenditure on the availability advertising as the product diffusion progresses. These results are illustrated with suitable numerical examples.