Experimental assessment of heat transfer and pressure drop of nanofluid as a coolant in corrugated channels

Journal of Thermal Analysis and Calorimetry - Over the last few decades, tremendous consideration is drawn towards corrugation surfaces because of their advantages over the improvement in thermal...     

Metal-Assisted Oxidative Cyclization of Arylamidrazones I. Synthesis of 3-Acetyl-1,4-dihydro-1-phenyl-1,2,4-benzotriazine

In the presence of RuCl₃, N-phenylamidrazone underwent oxidative cyclization into 1,4-dihydro-1-phenyl-1,2,4-benzotriazine, the structure of which is established by spectral and X-ray diffraction data.     

Conducting polymers. I. Electrical conductivity of poly(bis-p-phenylenediaminosulphoxide)

Poly(bis-p-phenylenediaminosulphoxide) was prepared by Michael addition of p-bis-N-sulphinylphenylenediamine with p-phenylenediamine at 150°C. Thermal and electrical behaviors of the polymer have been studied. The polymer is found to have increased conductivity possibly due to the participation of lone pairs of electrons on nitrogen and sulphur atoms with σ bond of the macrochain. Thermogravimetric analysis indicates that the polymer is fairly stable than other conducting polymers up to 200°C. The activation energy of the polymer was measured and found to be 13 kcal mol^?1.     

Die Veresterungsgeschwindigkeiten der Monoaminobenzoesäuren und der 1- und 2-Pyridinkarbonsäuren in Glykol und Glyzerin

Zusammenfassung Es werden die Veresterungsgeschwindigkeiten der Monoaminobenzoesäuren und der 1- und 2-Pyridinkarbonsäuren bei 25° mit Chlorwasserstoff als Katalysator sowohl in wasserfreiem als auch in wasserhaltigem Glykol und in wasserfreiem Glyzerin gemessen, die derm- und derp-Aminobenzoesäure und der 2-Pyridinkarbonsäure (Nikotinsäure) auch in wasserhaltigem Glyzerin. Die Abhängigkeit der monomolekularen Geschwindigkeitskonstanten vom Wassergehalt (w) des Mediums und dem Überschuß der Konzentration der Salzsäure über die der organischen Säure, bzw. ihres Esters (C) wird für die drei zuletzt genannten Säuren durch Formeln dargestellt. Diese Geschwindigkeitskonstanten nehmen durchwegs sowohl in wasserfreiem als auch in wasserhaltigem Glykol und Glyzerin nicht nur rascher als die Konzentration der gesamten Salzsäure, sondern auch als die des obigen Überschusses, d. h. der freien Salzsäure, zu.FürC=1/3 sind beiw=0.03 die Geschwindigkeitskonstanten derm- und derp-Aminobenzoesäure und der Nikotinsäure in Äthylalkohol um 20–30 %, die der Anthranilsäure um 70%, die der Pikolinsäure um 130% größer als in Glykol, beiw=0.7 dagegen die der drei ersteren Säuren um 35–50% kleiner.In Glykol sind die Konstanten bei der Anthranilsäure und den Pyridinkarbonsäuren kleiner als in Glyzerin, bei den übrigen wie bei den früher untersuchten Säuren aber größer.Die sterische Wirkung der Aminogruppe in Orthostellung ist in Glykol größer, in Glyzerin kleiner als in Äthylalkohol.Unter gleichen Bedingungen Bind die Konstanten der Veresterungsgeschwindigkeit der Nikotinsäure in Glykol und Glyzerin etwa viermal, in Äthylalkohol nur etwa zweimal größer als die der Pikolinsäure.     

Heats of adsorption of linear CO species adsorbed on the Au degrees and Ti+delta sites of a 1% Au/TiO2 catalyst using in situ FTIR spectroscopy under adsorption equilibrium

The heats of adsorption of two linear CO species adsorbed on the Au degrees particles (denoted L(Au degrees)) and on the Ti(+delta) sites (denoted L(Ti+delta)) of a 1% Au/TiO(2) catalyst are determined as the function of their respective coverage by using the AEIR procedure (adsorption equilibrium infrared spectroscopy) previously developed. Mainly, the evolutions of the IR band area of each adsorbed species (2184 cm(-1) for L(Ti+delta) and at 2110 cm(-1) for L(Au degrees)) as a function of the adsorption temperature T(a), at a constant CO adsorption pressure P(CO), provide the evolutions of the coverages theta(LTi+delta) and theta(LAu degrees ) of each adsorbed CO species with T(a) in isobar conditions that give the individual heats of adsorption. It is shown that they linearly vary from 74 to 47 kJ/mol for L(Au degrees ) and from 50 to 40 kJ/mol for L(Ti+delta) at coverages 0 and 1, respectively. These values are consistent with literature data on model Au particles and TiO(2). In particular, it is shown that the mathematical formalism supporting the AEIR procedure can be applied to literature data on Au-containing solids (single crystals and model particles).     

Spectrophotometric determination of cadmium(II) using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

The complex of cadmium with the reagent 2-(-5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) has been studied. The composition, stability constant, and free energy change of formation of the complex have been determined. A sensitive spectrophotometric method for the determination of cadmium has been developed and applied for a range of concentration of 0.4–4.0 μg/ml cadmium using the complex Cd-5-Br-PADAP. The optimum conditions for maximum sensitivity of determination such as standing time, pH, wavelength, and order of addition have been determined. The effect of foreign ions on this method has been also studied.     

Electroanalysis with tungsten electrodes : I. The tungsten/platinum bimetallic pair in potentiometry at zero current

The W/Pt bimetallic pair has been applied in various potentiometric titrations. Except for the neutralization of dicarboxylic acids, e.g., oxalic, the pair is suitable for neutralization titrations where ΔE/ΔV values at the equivalence point are higher on W than on Pt. Tungsten oxides increase the inflexion pd. The pair is also suitable for oxidation/reduction titrations using permanganate, dichromate, and ceric sulfate, and for precipitation reactions with silver nitrate. However, it gives a small inflexion pd in the oxidation of thiosulfate by iodine. EDTA titrations of copper, magnesium, and calcium give a sharp inflexion in the case of copper only. This pair may be useful in routine analyses requiring a robust electrode assembly but not a high degree of accuracy.     

2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol as a reagent for the spectrophotometric determination of La(III), Y(III), and Ce(III)

The complexes of the reagent 5-Br-PADAP with the metal ions La(III), Ce(III), and Y(III) have been studied.The composition and stability of these complexes have been determined. A sensitive spectrophotometric procedure for the determination of the metal ions La(III), Ce(III), and Y(III) has been proposed. The limitations of this procedure and the effect of other ions have been studied.     

Heats of adsorption using temperature programmed adsorption equilibrium: application to the adsorption of CO on Cu/A12O3 and H2 on Pt/Al2O3

A new simple analytical procedure is described that allows the determination of the heats of adsorption (denoted E(theta)) of adsorbed species at several coverages (theta's) using a single experiment. This procedure is an extension of an original method previously developed (denoted AEIR: adsorption equilibrium infrared spectroscopy). A mass spectrometer is used to determine the amounts of gas (in the present study, CO and H2) either desorbed from or adsorbed on a metal supported catalyst (4.7% Cu/Al2O3 and 2.9% Pt/Al2O3) during the perturbation of the adsorption equilibrium due to a controlled change of the adsorption temperature (Ta) at a quasi-constant adsorption pressure (Pa). These amounts allow us to follow the evolution of the adsorption equilibrium coverage (theta(e)) with Ta at the quasi-constant partial pressure (Pa). Then, the curve theta(e) = f(Ta) provides Etheta = f(theta) with the support of an adsorption model. This procedure presents several advantages as compared to the TPD methods, in particular, considering the theoretical supports linked to the exploitation of the experimental data. As compared to AEIR, the TPAE procedure allows one to study the heats of adsorption of adsorbed species that are not detectable by IR. However, it is not adapted if surface reactions occur in parallel to adsorption/desorption processes.     

Flow injection determination of cobalt after its sorption onto polyurethane foam loaded with 2-(2-thiazolylazo)-p-cresol (TAC)

An electrochemically stable monolayer of tris(2,2'-bipyridyl)ruthenium(II) was obtained for the first time. It was based on the electrostatic attachment of Ru(bpy)(3)(2+) to the benzene sulfonic acid monolayer film, which was covalently bound onto glassy carbon electrode by the electrochemical reduction of diazobenzene sulfonic acid. The surface-confined Ru(bpy)(3)(2+) underwent reversible surface process, and reacted with the coreactant, tripropylamine, to produce electrochemiluminescence. In view of the stability of the electrode, the results strongly suggested that light was emitted from the surface-confined Ru(bpy)(3)(2+), not from the detached Ru(bpy)(3)(2+). The Ru(bpy)(3)(2+) modified electrode was used to the determination of tripropylamine. It showed good linearity in the concentration range from 5 muM to 1 mM with a detection limit of 1 muM (S/N=4). The good stability of the Ru(bpy)(3)(2+) modified electrode also showed that the benzene sulfonic acid monolayer film prepared can be served as an excellent support to construct multilayers.