Coexisting synchronous and asynchronous states in locally coupled array of oscillators by partial self-feedback control

We report the emergence of coexisting synchronous and asynchronous subpopulations of oscillators in one dimensional arrays of identical oscillators by applying a self-feedback control. When a self-feedback is applied to a subpopulation of the array, similar to chimera states, it splits into two/more sub-subpopulations coexisting in coherent and incoherent states for a range of self-feedback strength. By tuning the coupling between the nearest neighbors and the amount of self-feedback in the perturbed subpopulation, the size of the coherent and the incoherent sub-subpopulations in the array can be controlled, although the exact size of them is unpredictable. We present numerical evidence using the Landau-Stuart (LS) system and the Kuramoto-Sakaguchi (KS) phase model.Comment: 13 pages, 13 figures, accepted for publication in CHAOS (July 2017

ON CONFORMAL QUASI HEMI-SLANT SUBMERSIONS FROM LORENTZIAN PARA SASAKIAN MANIFOLDS ONTP RIEMANNIAN MANIFOLDS

In the present article, our purpose is to define and study conformal quasi hemi-slant submersions (cqhs submersions, in short) from Lorentzian para Sasakian manifolds onto Riemannian manifolds. Its geometric properties are also investigated. Lastly, we give a non-trivial example for this type of submersio

5-Exo-dig, 5-exo-trig cascade radical cyclisation on sugar-furanose templates: entry to angularly fused oxa-and dioxa-triquinane skeletons

Serial radical cyclisation on sugar-furanose templates to create angularly fused oxa- and dioxa-triquinane skeletons has been described, the salient feature of this approach being to incipiently generate a tertiary radical from cyclopropylmethyl bromide with simultaneous release of allyl group and to subsequently incorporate it in the triquinane system

A Simple and Sensitive HPTLC Method for Simultaneous Determination of Metformin Hydrochloride and Sitagliptin Phosphate in Tablet Dosage Form

A simple, rapid, and precise high-performance thin-layer chromatographic (HPTLC) method for simultaneous estimation of two antidiabetic drugs, metformin hydrochloride and sitagliptin phosphate, in tablet dosage form has been developed and validated. Chromatography was performed on silica gel 60 F254 plates with butanol : water : glacial acetic acid (6 : 2 : 2, v/v/v) as mobile phase. This system gave a good resolution for metformin hydrochloride ( value of 0.35 ± 0.01) and sitagliptin phosphate ( value of 0.75 ± 0.01). Detection and quantification were carried out at 227 nm. The linear regression data for the calibration plot showed a good relationship with and 0.9991 for metformin hydrochloride and sitagliptin phosphate, respectively. The method was validated for precision and recovery. The limits of detection and quantification were 13.05 and 39.56 ng/μL for metformin hydrochloride and 2.65 and 8.03 ng/μL for sitagliptin phosphate, respectively. The amounts of the drugs in the marketed formulation were 99.86% and 98.91% for metformin hydrochloride and sitagliptin phosphate, respectively

Treatment of intertrochanteric femur fracture in elderly patients with the proximal femoral nail antirotation: evaluation in terms of union and functional outcome

Background: Trochanteric fractures almost invariably occur as a result of a trivial fall involving both direct and indirect forces. Fixation in the geriatric population generally consists of weakened, osteoporotic bone; intramedullary devices (PFNA) carry an advantage over other load sharing devices by not having to depend on plate fixation with bone screws purchasing a compromised lateral cortex. The purpose of the present study is to verify the theoretical advantages of the proximal femoral nail in elderly osteoporotic patients and eventually functional outcome of the patient.Method: A total of 30 patients with age >60 years with intertrochanteric femur fractures managed with proximal femoral nail anti-rotation for prospective study. Harris hip score had been used in our study for regular follow up and evaluation at each and every follow up visit.Results: Average Harris hip score at the end of study showed mean value of 87, ranged from 65 to 94 with almost 73% patients showing excellent or good outcome. And 100% fractures got united with a good component position and average time to bone healing was 14 weeks.Conclusions: PFNA are now favored in western countries and there are multiple studies coming from that region to support this. Due to advantages of high union rate, early postoperative mobilization, and short operation time, PFNA osteosynthesis is the method of choice for surgical treatment of stable and unstable osteoporotic intertrochanteric femoral fractures

Iontophoresis: A Potential Emergence of a Transdermal Drug Delivery System

The delivery of drugs into systemic circulation via skin has generated much attention during the last decade. Transdermal therapeutic systems propound controlled release of active ingredients through the skin and into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. However, the excellent impervious nature of the skin offers the greatest challenge for successful delivery of drug molecules by utilizing the concepts of iontophoresis. The present review deals with the principles and the recent innovations in the field of iontophoretic drug delivery system together with factors affecting the system. This delivery system utilizes electric current as a driving force for permeation of ionic and non-ionic medications. The rationale behind using this technique is to reversibly alter the barrier properties of skin, which could possibly improve the penetration of drugs such as proteins, peptides and other macromolecules to increase the systemic delivery of high molecular weight compounds with controlled input kinetics and minimum inter-subject variability. Although iontophoresis seems to be an ideal candidate to overcome the limitations associated with the delivery of ionic drugs, further extrapolation of this technique is imperative for translational utility and mass human application

Nested Helmholtz coil design for producing homogeneous transient rotating magnetic fields

Citation: Podaru, G., Moore, J., Dani, R. K., Prakash, P., & Chikan, V. (2015). Nested Helmholtz coil design for producing homogeneous transient rotating magnetic fields. Review of Scientific Instruments, 86(3), 6. doi:10.1063/1.4908173Electromagnets that can produce strong rotating magnetic fields at kHz frequencies are potentially very useful to exert rotating force on magnetic nanoparticles as small as few nanometers in size. In this article, the construction of a pulsed high-voltage rotating electromagnet is demonstrated based on a nested Helmholtz coil design. The energy for the coils is provided by two high-voltage discharge capacitors. The triggered spark gaps used in the experiments show sufficient accuracy to achieve the high frequency rotating magnetic field. The measured strength of the rotating magnetic field is 200 mT. This magnetic field is scalable by increasing the number of turns on the coils, by reducing the dimensions of the coils and by increasing the discharge current/voltage of the capacitors. (C) 2015 AIP Publishing LLC

Multiaxial fatigue studies on carbon steel piping material of Indian PHWRs

The tests studies and analyses have been carried out in the area of “Multiaxial Fatigue” with an objective to improve the damage assessment methodologies and design rules. Nearly 50 numbers of fatigue tests were conducted on solid and tubular specimens of SA333Gr.6 material under pure axial, pure shear and combined axial-torsion in-phase/ out-of-phase loading combinations. A software has been developed for the evaluation of multiaxial fatigue damage for the analyses of tests data using different invariant fatigue models such as ASME Sec.III code procedures, von-Mises etc. The fatigue crack initiation life was predicted using the best fit axial fatigue life curve (without use of safety factors). These tests and their analyses have helped in understanding the fatigue failure behavior of piping material under complex cyclic loadings where the principal directions rotate during a loading cycle. The crack initiation angles have also been measured by analyzing the image of the tested specimens. The measured crack angles will help in validation of the critical plane based models

Fatigue studies on stainless steel piping materials and components: Indian AHWR

As a part of component integrity test program at Bhabha Atomic Research Centre, fatigue tests on full scale pipe and pipe welds were conducted in addition to CT and TPB specimens. In this paper the outcome of this program is discussed. Specimen testing was conducted to determine the basic cyclic stress strain curve, LCF and FCGR properties. FCGR tests were conducted on CT and TPB specimens to understand the effect of different conditions: Specimen level tests result show that, for the present grade of material, the FCGR is not significantly affected by specimen type (CT and TPB), specimen thickness and notch orientation. FCGR resistance of the hot wire GTAW is superior compared to that of conventional SMAW. The effects of stress ratio are mildly significant at lower R-values for base metal but are significant for weld metal. Component tests were conducted to understand the effect of the following variables:(a)Component type and size: pipe and pipe weld, Pipe diameters 170 mm and 324 mm,(b)Pipe and pipe weld: initial notch in pipe base, and girth welded pipe, (c) Pipe welds: Conventional GTAW/SMAW and hot wire narrow gap GTAW, (d)Environment: Air and water, (e) Type of loading: Constant amplitude cyclic, vibration, Block, overload and underload. Results indicated that the fatigue life of the component is reduced under water environment compared to air environment. Fatigue life of the pipe subjected to block loading (increasing stress ratio followed by decreasing stress ratio), intermittent overloading and underloading is also decreased compared to that of constant amplitude loading. Vibration loading reduces fatigue life significantly. Crack growth in thickness direction is more compared to circumferential direction for all types of loading which is desirable for demonstration of LBB criteria. Fatigue life of the notched component has also been predicted using the Paris constants data from the specimen level tests. Fatigue crack growth and the crack shape of the growing crack have been evaluated for regular interval of loading cycles. The predictions compares well with those of experiments