Distribution studies of metal ions on stannic arsenate in butanol-HNO3 systems: Quantitative separation of Ni−Fe,Ni−Cu,Cd−Hg and Pb−Hg

Summary This paper deals with systematic distribution studies of metal ions on stannic arsenate in butanol-HNO₃ systems. K_d values of metal ions have been determined by the batch process in solvent systems containing varying proportions of butanol and 50% HNO₃. Quantitative binary separations of Ni–Fe, Ni–Cu, Cd–Hg and Pb–Hg have been obtained on the basis of information from the studies.     

Influence of Organic Additive on the Morphological, Electrical and Electrochromic Properties of Sol-Gel Derived WO3 Coatings

The WO₃ electrode is ubiquitous in an electrochromic device (ECD) and is a common choice as the electrochromic (EC) layer. EC films were deposited on different substrates by spin coating using peroxotungstic acid based precursor solutions followed by appropriate thermal treatment. Many properties of the films, including some of the EC properties dependant on microstructure of the films, were found to be modified by the addition of small amounts of organic acid to the precursor solution. A study of structural, electrical and electrochromic properties of films cast by using precursor solution comprising 0 to 10 wt% of oxalic acid dihydrate (OAD) was carried out in terms of surface morphology, electrical resistance, structure and EC response. The important findings are that the addition of oxalic acid to the precursor solution results in films with excellent EC properties, devoid of cracks and decreases their dc electrical resistance.     

Structure of poly(methyl methacrylate) chains adsorbed on sapphire probed using infrared-visible sum frequency generation spectroscopy

We have studied the orientation of the train segments of a poly(methyl methacrylate) (PMMA) adsorbed layer at the CCl4-sapphire interface using surface-sensitive IR-visible sum frequency generation (SFG) spectroscopy. The SFG spectra of PMMA chains adsorbed on sapphire indicate ordered ester methyl groups. In comparison, we did not observe any significant contributions from the backbone methylene and alpha methyl groups, suggesting that these groups are disordered. No change in the structure of the adsorbed layer is observed upon cooling the solvent below the theta temperature; this is consistent with the picture of flat adsorbed chains on the surface. Interestingly, the orientation of the ester methyl groups of a spin-coated PMMA film at the PMMA-sapphire interface is similar to that of the same groups in the chains adsorbed from solution.     

Experimental verification of improved effective index method for endlessly single mode photonic crystal fiber

We report the experimental verification of Improved Effective Index Method (IEIM) for Endlessly Single Mode Photonic Crystal Fibers (ESM PCFs) from far field intensity measurements. In this paper all the key parameters i.e. V-Number, effective refractive index of the cladding, radius of the core and numerical aperture have been obtained from the experimentally measured far-field intensity pattern of ESM-PCFs. It is shown that the transmission characteristics of ESM-PCFs match with the simulation result obtained using IEIM and also with the core diameter of PCF obtained from scanning electron microscope (SEM) within the experimental limit.     

Abkühlungscharakteristik einer gut wärmeleitenden Platte,die bei der Bewegung durch ein Fluid gestreckt wird

Zusammenfassung Das Abkühlungsverhalten einer gut wärmeleitenden Platte, die durch ein Fluid bewegt und dabei nach einem beliebigen Potenzgesetz gestreckt wird, wurde untersucht. Der Impulstransport wird dabei durch eine Gleichung beschrieben, die der Falkner-Skan-Gleichung mit einem Parameter für die Dehnung ähnelt. Für das thermische Problem wurden bezüglich des Ortes ähnliche Lösungen gefunden, die sowohl für kleine als auch große Werte des Fließabstandes gültig sind. Die Konvergenz der Reihen für kleine-Werte konnte durch die Euler-Transformation verbessert werden, so daß die Ergebnisse für alle-Werte Gültigkeit haben.

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The cooling of a low heat resistance stretching sheet moving through a fluid

The cooling characteristics of a low-heat-resistance sheet moving through a fluid have been studied for arbitrary power law stretching. The momentum transfer is governed by an equation that resembles the Falkner-Skan equation with stretching as a parameter. For the thermal problem, locally similar solutions have been obtained for small and large values of the streamwise distance. The convergence of low series has been improved by Euler transformation to yield results valid for all values of.

     

Structural and electrical transport properties of ZnxFe3−xO4 thin film deposited on Si (1 1 1) by pulsed-laser deposition

Polycrystalline thin films of Fe_3−xZn_xO₄ (x = 0.0, 0.01 and 0.02) were prepared by pulsed-laser deposition technique on Si (1 1 1) substrate. X-ray diffraction studies of parent as well as Zn doped magnetite show the spinel cubic structure of film with (1 1 1) orientation. The order–disorder transition temperature for Fe₃O₄ thin film with thickness of 150 nm are at 123 K (Si). Zn doping leads to enhancement of resistivity by Zn²⁺ substitution originates from a decrease of the carrier concentration, which do not show the Verwey transition. The Raman spectra for parent Fe₃O₄ on Si (1 1 1) substrate shows all Raman active modes for thin films at energies of T_2g¹, T_2g³, T_2g², and A_1g at 193, 304, 531 and 668 cm⁻¹. It is noticed that the frequency positions of the strongest A_1g mode are at 668.3 cm⁻¹, for all parent Fe₃O₄ thin film shifted at lower wave number as 663.7 for Fe_2.98Zn_0.02O₄ thin film on Si (1 1 1) substrate. The integral intensity at 668 cm⁻¹ increased significantly with decreasing doping concentration and highest for the parent sample, which is due to residual stress stored in the surface.     

International Guidelines for Bioanalytical Method Validation: A Comparison and Discussion on Current Scenario

US FDA released guidelines for bioanalytical method validation in 2001 and it became the basis for guidelines such as ANVISA and EMA. Even though there is a general agreement between these guidelines in terms of evaluation of validation parameters, significant diversity exists with respect to methodology employed. Present review compares and summarizes the regulatory guidelines issued by US FDA, ANVISA and EMA for bioanalytical method validation. This review also discusses evaluation of certain validation parameters such as matrix effect, incurred sample reanalysis, various stability aspects, effect of anticoagulant counter ions, specificity in the presence of concomitant medications, and identification of pharmacokinetic repeats wherein specific guidance and general consensus amongst scientific community does not exist.     

Single-Pot Synthesis of Spiroannulated Dihydrofurans by Iodine–Ammonium Acetate–Mediated Reaction of Dimedone with Aldehydes

Iodine–ammonium acetate–mediated annealation of dimedone with aldehydes led to facile formation of spirodihydrofuran in good yields through tandem Knoevenagel–Michael iodonation and cyclodehydroiodonation reactions in a single pot.