Constrained-layer Dampers for Attenuation of Structural Vibration

In a constrained-layer damping system, a thin layer of a viscoelastic material is applied over the vibrating substrate. and covered with a stiff constraininglayer of a metal or a fibre-reinforcedplastic. Several viscoelastic materials based on elastomeric blends of copoly (acrylonitrilebutadiene) and polyvinyl chloride were developed. These materials were characterised for hardness, tensile properties, ozone resistance, and electrical and dynamic mechanical properties. Two polymer compositions were used to fabricate 1 mm sheets. The sheets were fixed on an aluminium substrate with a rigid epoxy glue. A fibre-reinforced plastic sheet of 300 p was fixed on the viscoelastic layer by a rigid epoxy glue. The experimental setup for the measurement of vibration response has been elaborated. The study was carried out with and without the constrained-layer damping system. The vibration attenuation achieved was to a minimum of 5-7 dB at 200-500 Hz and to a maximum of 9- 16 dB at 3000 - 4000 Hz for the selected constrainedlayer damping system

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

Bioconvective nanofluid flow over an exponential stretched sheet with thermophoretic particle deposition

The current work is being done to investigate the flow of nanofluids across a porous exponential stretching surface in the presence of a heat source/sink, thermophoretic particle deposition, and bioconvection. The collection of PDEs (partial differential equations) that represent the fluid moment is converted to a system of ODEs (ordinary differential equations) with the use of suitable similarity variables, and these equations are then numerically solved using Runge Kutta Fehlberg and the shooting approach. For different physical limitations, the numerical results are visually represented. The results show that increasing the porosity characteristics reduces velocity. The mass transfer decreases as the thermophoretic limitation increases. Increases in the porosity parameter reduce skin friction, increases in the solid volume fraction improve the rate of thermal distribution, and increases in the thermophoretic parameter increase the rate of mass transfer

An axisymmetric hypersingular boundary integral formulation for simulating acoustic wave propagation in supercavitating flows

10.1016/j.jsv.2012.04.031Journal of Sound and Vibration331194313-4342JSVI

Analysis of oxidation products of 10-[3'-N-benzylaminopropyl]- phenoxazine redox indicator by spectral and cyclic voltammetric methods

Synthesis of 10-(3'-N-benzylamino)propyl]phenoxazine BAPP] is accomplished in two steps. The first step involved N-10-alkylation of parent phenoxazine via phase transfer catalysis (PTC) followed by iodide-catalysed nucleophilic substitution of the N-10-propyl chloride with N-benzylamine. BAPP formed is purified by column chromatography. In the second stage BAPP undergoes one-electron oxidation with Ce(IV) to form a pink radical cation BAPP(+.)]. In the presence of more than one equivalent of Ce(IV), the radical cation undergoes a second one-electron oxidation to form a brownish yellow coloured dication BAPP(2+)], which is characterized by UV-Vis, IR and mass-spectral methods. The biological functions of phenoxazines are connected to a great extent with their ability to undergo reversible redox conversion and therefore the electrochemical behaviour of BAPP is investigated by cyclic voltammetry. Other cyclic voltammetric parameters have also been determined. Bromine in acid medium oxidizes BAPP to three products as shown by HPLC. The tentatively predicted structures based on the mass-spectral data support the formation of three brominated oxidized products. In order to explore the analytical applications, the optimum conditions for the use of BAPP as redox indicator in the macro and micro estimation of ascorbic acid, methionine, isoniazid, phenylhydrazine hydrochloride and biotin using chloramine-T as an oxidant have been developed. The indicator gives sharp and stoichiometric end-points. During the titration, BAPP initially undergoes a reversible one-electron oxidation. With progress of titration, the radical pink cation is oxidized to a blue coloured dication with the loss of one more electron. The utilization of BAPP as an indicator for oxidation-reduction reactions for the volumetric determination of bioanalytically important species such as ascorbic acid, methionine and isoniazid in real samples is significant

Analysisf of oxidation products of 10-3'-n-benzy!aminopropyl-phenoxianine redox indicatoor by spectal and cyclic voltammeric

Synthesis of 10-[(3'-N-benzylamino)propyl]phenoxazir.e [BAPP] is accomplished in two steps. The first step involved N10-a!kylation of parent phenoxazine via phase transfer catalysis (PTC) followed by iodide-catalysed nucleophilic substitution of the Nll!-propyl chloride with N-benzylamine. BAPP formed is purified by column chromatography. In the second stage BAPP undergoes one-electron oxidation with Ce(IV) to form a pink radical cation [BAPP1']. In the presence of more than one equivalent of Ce(IV), the radical cation undergoes a second one-electron oxidation to form a brownish yellow coloured dication [BAPP2], which is characterized by UV-Vis, IR and mass-spectral methods. The biological functions of phenoxazines are connected to a great extent with their ability to undergo reversible redox conversion and therefore the electrochemical behaviour of BAPP is investigated by cyclic voltammctry. Other cyclic voltammetric parameters have also been determined. Bromine in acid medium oxidizes BAPP to three products as shown by HPLC. The tentatively predicted structures based on the mass-spectral data support the formation of three brominated oxidized products. In order to explore the analytical applications, the optimum conditions for the use of BAPP as redox indicator in the macro and micro estimation of ascorbic acid, methionine, isoniazid, phenylhydrazine hydrochloride and biotin using chloramine-T as an oxidant have been developed. The indicator gives sharp and stoichiometric end-points. During the titration, BAPP initially undergoes a reversible one-electron oxidation. With progress of titration, the radical pink cation is oxidized to a blue coloured dication with the loss of one more electron. The utilization of BAPP as an indicator for oxidation-reduction reactions For the volumetric determination of bioanalytically important species such as ascorbic acid, methionine and isoniazid in real samples is significant. © Indian Academy of Sciences

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Nonlinear convective heat and mass transfer of Oldroyd-B nanofluid over a stretching sheet in the presence of uniform heat source/sink

The present study addresses the three-dimensional flow and nonlinear radiative heat transfer of an Oldroyd-B nanofluid flow over a stretching surface with the addition effects of uniform heat source/sink and convective boundary conditions. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These nonlinear ordinary differential equations are then solved numerically by RKF-45 method. The effects of physical parameters on velocity, temperature and concentration profiles are investigated and discussed. The result reveals that the nonlinear radiation is more effective than that of linear radiation. Keywords: Oldroyd-B fluid, Nanoparticles, Nonlinear thermal radiation, Convective boundary conditions, Uniform heat source/sin