Kantorovich variant of a new kind of q‐Bernstein–Schurer operators

Ren and Zeng (2013) introduced a new kind of q‐Bernstein–Schurer operators and studied some approximation properties. Acu et al. (2016) defined the Durrmeyer modification of these operators and studied the rate of convergence and statistical approximation. The purpose of this paper is to introduce a Kantorovich modification of these operators by using q‐Riemann integral and investigate the rate of convergence by means of the Lipschitz class and the Peetre's K‐functional. Next, we introduce the bivariate case of q‐Bernstein–Schurer–Kantorovich operators and study the degree of approximation with the aid of the partial modulus continuity, Lipschitz space, and the Peetre's K‐functional. Finally, we define the generalized Boolean sum operators of the q‐Bernstein–Schurer–Kantorovich type and investigate the approximation of the Bögel continuous and Bögel differentiable functions by using the mixed modulus of smoothness. Furthermore, we illustrate the convergence of the operators considered in the paper for the univariate case and the associated generalized Boolean sum operators to certain functions by means of graphics using Maple algorithms. Copyright © 2017 John Wiley & Sons, Ltd.     

Application of rainbow schlieren deflectometry for concentration measurements in an axisymmetric helium jet

 The rainbow schlieren deflectometry technique was used to measure oxygen concentrations in a laminar, isothermal helium jet discharged vertically into ambient air. The concentration distributions were inferred from the color schlieren image by taking into consideration the sampling interval and noise in measurements, especially near the jet center. Excellent quantitative agreement was reached between measurements from schlieren and a continuous sampling probe. This work demonstrates the capability of the schlieren technique for providing accurate, spatially-resolved, nonintrusive, full-field of view measurements of species concentration in an isothermal binary system. Because the basic quantity measured is the refractive index, the present schlieren technique can be extended for quantitative measurements of other scalar flow properties related to the refractive index. Received: 21 April 1997 / Accepted: 14 November 1997     

Hydrodynamic injection with pneumatic valving for microchip electrophoresis with total analyte utilization

A novel hydrodynamic injector that is directly controlled by a pneumatic valve has been developed for reproducible microchip CE separations. The PDMS devices used for the evaluation comprise a separation channel, a side channel for sample introduction, and a pneumatic valve aligned at the intersection of the channels. A low pressure (≤ 3?psi) applied to the sample reservoir is sufficient to drive sample into the separation channel. The rapidly actuated pneumatic valve enables injection of discrete sample plugs as small as ~ 100?pL for CE separation. The injection volume can be easily controlled by adjusting the intersection geometry, the solution back pressure, and the valve actuation time. Sample injection could be reliably operated at different frequencies (< 0.1?Hz to > 2?Hz) with good reproducibility (peak height relative standard deviation ≤ 3.6%) and no sampling biases associated with the conventional electrokinetic injections. The separation channel was dynamically coated with a cationic polymer, and FITC-labeled amino acids were employed to evaluate the CE separation. Highly efficient (≥ 7.0 × 103 theoretical plates for the ~2.4-cm-long channel) and reproducible CE separations were obtained. The demonstrated method has numerous advantages compared with the conventional techniques, including repeatable and unbiased injections, little sample waste, high duty cycle, controllable injected sample volume, and fewer electrodes with no need for voltage switching. The prospects of implementing this injection method for coupling multidimensional separations for multiplexing CE separations and for sample-limited bioanalyses are discussed.     

Synthesis and characterization of Eu doped SrY2O4 phosphor

The present paper reports that TL glow curve and kinetic parameter of Eu³⁺ doped SrY₂O₄ phosphor irradiated by beta source. Sample was prepared by solid state preparation method. Sample was characterized by XRD analysis and particle size was calculated by Debye–Scherrer formula. The sample was irradiated with Sr-90 beta source giving a dose of 10 Gy and the heating rate used for TL measurements are 6.7 °C/s. The samples display good TL peaks at 106 °C, 225 °C and 382 °C. The corresponding kinetic parameters are calculated. The photoluminescence excitation spectrum at 247 and 364 nm monitored with 400 nm excitation and the corresponding emission peaks at 590, 612 and 624 nm are reported.     

Electrical characterization of PVA-based nanocomposite electrolyte nanofibre mats doped with a multiwalled carbon nanotube

An attempt has been made to prepare and characterise ammonium thiocyanate (NH₄SCN) salt and a multiwall carbon nanotube (MWNT)-doped polyvinyl alcohol-based nanofibre mats using an electrospinning process. The X-ray diffraction result shows an improvement in the amorphous nature of composite electrolyte fibre mats with increasing concentrations of the MWNT filler. The DSC behaviour of these nanofibre mat exhibits better thermal response upon dispersal of the filler. Composite electrolyte nanofibre mat doped with 6 wt% MWNT shows optimum conductivity, viz., 5.8?×?10^?4 Scm^?1. The temperature dependence of the bulk electrical conductivity displays a combination of Arrhenius and Vogel–Tammam–Fulcher nature. Dielectric loss studies have also been used to understand the conduction process in the system. Jonscher power law seems to be obeyed during ac conductivity measurements of the fibre mats.     

Intra–intermolecular gel-free cyclopolymerization of nonconjugated diene with peroxodiphosphate/different activators redox pairs

Gel-free cyclopolymerization of N,N′-methylenebisacrylamide has been carried out using potassium peroxodiphosphate (PDP) as initiator in combination with different activators such as mercaptosuccinic acid (MSA) and thioglycollic acid (TGA) in an inert atmosphere at 45 ± 1°C and 40 ± 1°C, respectively. The rate of polymerization was found proportional to the first power of the monomer and activator concentration and the half-power of PDP in both redox systems. A mechanism involving cyclopolymerization in the propagation path has been proposed. © 1993 John Wiley & Sons, Inc.     

Cytotoxic Agents in the Treatment of Laryngeal Sarcoidosis: A Case Report and Review of the Literature

SUMMARY: Sarcoidosis is a multisystem disease with various clinical manifestations. It is characterized primarily on a histopathologic basis by the presence of noncaseating granulomata. Laryngeal involvement reportedly occurs in 3-5% of cases, and it is typically localized to the supraglottic region. Patients often present with hoarseness, dysphagia, stridor, or dyspnea. Laryngoscopy typically demonstrates a pale, edematous epiglottis studded with nodules. Tissue biopsy reveals the classic noncaseating granuloma; however, the finding is not diagnostic. Sarcoidosis remains a diagnosis of exclusion to be entertained once other verifiable etiologies for granulomatous disease of the larynx, such as TB, syphilis, fungal infection, berylliosis, or Wegener's granulomatosis, have been ruled out. Systemic corticosteroids remain the mainstay of treatment; however, new steroid-sparing therapies that target the inflammatory response of sarcoidosis are currently being investigated. The case history of a patient with laryngeal sarcoidosis who was managed with the immunosuppressant azathioprine (Imuran) is summarized along with a discussion of other treatment options.     

Ab-initio study of doped nanostructures—Mn-doped ultrathin ZnS films

An ab-initio study of the effects of the quantum confinement has been performed for the first time in the ultrathin ZnS films: unpassivated, passivated and the Mn-doped ones. A self-consistent full potential linear muffin tin orbital (FP-LMTO) method has been employed. The studied films have comparatively a large thickness range of 2.7–29.7 Å. The fundamental band gap increases exponentially with decrease in the size of the quantum confinement. The Mn-doped films reveal the localized impurity-induced states within the band gap and also in the conduction band region. The intense optical transitions between the Mn-induced states will appear at about 2.1 eV which is in excellent agreement with the observed peak in the photoluminescence experiments.     

Mean-velocity distributions of contra-swirling coaxial,confined jets

Conclusions From the study, it is observed that introduction of swirl in the central jet enhances the merger whereas higher swirl in the annulus enhances both mixing and flow development. On qualitative comparison with similar works (Gouldin et al. 1985; Ramos and Sommer 1983) it is seen that imposition of pressure gradient in form of expanded confinement enhances the capability of formation of central recirculation core. Wall static pressure distribution also gives an indication of the wall recirculation size.     

Phase conjugation in biharmonically pumped two-photon resonant systems

Phase conjugation through four-wave mixing is considered in a two-photon resonant medium pumped by two distinct-frequency counter-propagating beams. This configuration eliminates the formation of stationary spatial holes. The relative magnitude of the pump intensities plays an important role and the phase-conjugation efficiency is found to be maximum for unequal values of the pump intensities.