Free convection in a saturated porous medium adjacent to a non-isothermal vertical impermeable wall

Boundary layer analysis is performed for free convection in a saturated porous medium adjacent to non-isothermal vertical impermeable surfaces. The impermeable surface temperature is assumed to be an arbitrary function of the distance along the surface. The solutions are obtained in the form of perturbations to the isothermal case. Using the differentials of the wall temperature, which are functions of distance along the surface, as perturbation elements, universal functions are derived. These universal functions can be used to estimate the heat transfer to any type of wall temperature variation. Solutions for some specialized wall temperature variations are derived using these universal functions and are compared with the solutions that are available in the literature. The agreement is found to be good. The case of uniform wall heat flux turns out to be a special case of non-isothermal wall solution.Es wurde eine Untersuchung der Grenzschicht bei freier Konvektion in einem gesättigten porösen Medium, das an eine nicht isotherme undurchlässige Oberfläche angrenzt, durchgeführt. Die Temperatur der undurchlässigen Oberfläche wurde als beliebige Ortsfunktion der Oberfläche angenommen. Lösungen werden in Form von Störungen des isothermen Falles erhalten. Unter Benutzung der Differentiale der Wandtemperatur, welche Ortsfunktionen der Oberfläche sind, werden als Störfunktion universelle Funktionen erhalten. Diese universellen Funktionen können benutzt werden, um die Wärmeübertragung für beliebige Variationen der Wandtemperatur zu bestimmen. Für einige spezielle Wandtemperaturen werden Lösungen unter Benutzung dieser universellen Funktionen abgeleitet und mit Lösungen aus der Literatur verglichen; gute Übereinstimmung kann festgestellt werden. Der Fall der einheitlichen Wandwärmestromdichte stellt sich als Spezialfall der nicht isothermen Lösung heraus.     

Assessment of Acrylamide Degradation Potential of Pseudomonas aeruginosa BAC-6 Isolated from Industrial Effluent

Acrylamide finds diverse industrial applications but is considered an environmental threat because of its neurotoxic, carcinogenic, and teratogenic effects. Certain bacteria enzymatically degrade acrylamide to acrylic acid and ammonia. The present investigation was carried out to isolate and identify an acrylamide-degrading bacterium from industrial effluent. Bacterial growth and extent of acrylamide degradation in the presence of different acrylamide concentrations, nutrients, varied range of pH, and temperature were analyzed. Among the eight acrylamide-degrading isolates, isolate BAC-6 demonstrated the highest degradation, and based upon the partial 16S rDNA sequencing, it was identified as Pseudomonas aeruginosa. P. aeruginosa BAC-6 grew over a wide range of acrylamide concentrations, but the highest degradation was recorded at 500 mg/L concentration with concomitant cell growth. Among the carbon supplements, mannitol supported the highest growth and degradation. Maximum degradation was reported at neutral pH. A mesophilic temperature range (25–40 °C) facilitated conducive bacterial growth followed by degradation. The highest degradation and bacterial growth were observed at 30 and 35 °C, respectively. Thus, it could be inferred from the present investigation that cultural conditions strongly affected the degradation potential of P. aeruginosa BAC-6 and advocated the utilization of the isolate in bioremediation of sites polluted with acrylamide.     

Applications of EDXRF and INAA techniques for studying impact of industries to the environment

In this study we present quantitative elemental analysis techniques like energy dispersive X-ray fluorescence analysis and instrumental neutron activation analysis to assess the impact of industrial discharge on environment. Two cases are discussed, i.e., (a) enrichment of zinc levels in the soil (1080 ± 76 mg kg^?1) and zinc uptake ranging between 628 and 40 mg kg^?1 in edible plants and cereals grown in agricultural fields near an active zinc smelter, Rajasthan; (b) depth-wise distribution of Cr, Pb and other metals in the sediment core samples from Sundarban wetland, West Bengal, indicating waste discharge from tanneries and other industries.     

2,3-Diarylquinoxaline directed mono ortho-aroylation via cross-dehydrogenative coupling using aromatic aldehydes or alkylbenzenes as aroyl surrogate

2,3-Diarylquinoxaline directed mono ortho-aroylation protocol has been developed using aromatic aldehydes or alkybenzenes as aroyl surrogates. Out of the four available ortho sp² C–H bonds in the two aryl rings of 2,3-diarylquinoxaline one of the C–H bond is selectively ortho-aroylated. The reaction proceeds via the aroyl radical path in the case of aromatic aldehydes while the alkylbenzenes follow either an aroyl radical or a benzyl radical path. Varieties of functional groups present as substituents in 2,3-diarylquinoxalines, aromatic aldehydes and alkylbenzenes are tolerated under the present reaction conditions.     

Redox‐Mediated Synthesis of a Fe3O4–MnO2 Nanocomposite for Dye Adsorption and Pseudocapacitance

A logically chosen redox reaction of submerged Fe⁰ in an aqueous KMnO₄ solution has been reported. The template‐free reaction conditions produced gram amounts of a hierarchical flowerlike Fe₃O₄–MnO₂ nanocomposite. More precisely, freshly prepared Fe⁰ nanoparticles were prepared from air‐free hot water under submerged conditions using a door magnet. The black Fe⁰ particles were oxidized in water quantitatively by KMnO₄ in the solution phase and the nanocomposite was prepared. The material has been used as a dye adsorbent and the representative cationic dye uptake, recovery, and recycling of the dye becomes easy owing to the ferromagnetic properties and surface negative charge of the material. The nanocomposite also showed a higher specific capacitance (327 F g^?1 at 10 mV s^?1) than the reported values of pure MnO₂ and Fe₃O₄. The material exhibited a high energy density as well as a high power density, and remained stable even after a large number of charge–discharge cycles.     

Porous Solids Arising from Synergistic and Competing Modes of Assembly: Combining Coordination Chemistry and Covalent Bond Formation

Design and synthesis of porous solids employing both reversible coordination chemistry and reversible covalent bond formation is described. The combination of two different linkage modes in a single material presents a link between two distinct classes of porous materials as exemplified by metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). This strategy, in addition to being a compelling material‐discovery method, also offers a platform for developing a fundamental understanding of the factors influencing the competing modes of assembly. We also demonstrate that even temporary formation of reversible connections between components may be leveraged to make new phases thus offering design routes to polymorphic frameworks. Moreover, this approach has the striking potential of providing a rich landscape of structurally complex materials from commercially available or readily accessible feedstocks.     

Copolymerization of sec‐butenyl acetate with styrene via emulsion polymerization

The incorporation of allylic monomers into highly reactive vinyl polymerizations provides a means to control molecular weight, conversion, and Trommsdorff effect to produce copolymers with desirable performance characteristics. The copolymerization behavior of styrene with sec‐butenyl acetate, whose copolymerization properties have not been reported, is investigated. Copolymers were produced via semicontinuous emulsion polymerization and characterized via NMR, gel permeation chromatography, differential scanning calorimetry, dynamic light scattering, and atomic force microscopy. A high degree of chain termination due to allylic hydrogen abstraction was observed, as expected, with resultant decreases in molecular weight and in monomer conversion. However, high conversions were achieved, and it was possible to incorporate high percentages of the allylic acetate comonomer into the polymer chain. Copolymer thermal properties are reported. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3191–3203, 2007     

Lagrangian conditions for vector optimization in Banach spaces

We consider vector optimization problems on Banach spaces without convexity assumptions. Under the assumption that the objective function is locally Lipschitz we derive Lagrangian necessary conditions on the basis of Mordukhovich subdifferential and the approximate subdifferential by Ioffe using a non-convex scalarization scheme. Finally, we apply the results for deriving necessary conditions for weakly efficient solutions of non-convex location problems.