Showing papers by "Rama B. Bhat published in 2014"
TL;DR: The goal was to enhance the uniformly distributed positioning of pollen grains at the entrances of the microchannels and to provide identical fluid flow conditions for growing pollen tubes along each microchannel.
Abstract: A biocompatible polydimethylsiloxane (PDMS) biomicrofluidic platform is designed, fabricated and tested to study protuberance growth of single plant cells in a micro-vitro environment. The design consists of an inlet to introduce the cell suspension into the chip, three outlets to conduct the medium or cells out of the chip, a main distribution chamber and eight microchannels connected to the main chamber to guide the growth of tip growing plant cells. The test cells used here were pollen grains which produce cylindrical protrusions called pollen tubes. The goal was to adjust the design of the microfluidic network with the aim to enhance the uniformly distributed positioning of pollen grains at the entrances of the microchannels and to provide identical fluid flow conditions for growing pollen tubes along each microchannel. Computational fluid analysis and experimental testing were carried out to estimate the trapping efficiencies of the different designs.
18 citations
08 Sep 2014
TL;DR: In this article, a hybrid torsional vibration damper combining conventional CPVA with a magnetorheological (MR) damper is proposed to suppress torsion vibration at varying excitation frequencies.
Abstract: A hybrid torsional vibration damper is proposed in this study incorporating a conventional Centrifugal Pendulum Vibration Absorber (CPVA) and a Magnetorheological (MR) damper. While CPVAs are simple and reliable passive torsional vibration absorbers, their performance is limited to the designed tune conditions. MR dampers have recently received considerable attention due to their inherent fail-safe feature, low power requirement and capability to attenuate vibration under unpredictable environmental conditions. The present research aims at developing a novel hybrid torsional vibration damper combining conventional CPVA with the MR damper capable of suppressing torsional vibration at varying excitation frequencies. This research presents results from analytical investigation of rotor systems integrated with the proposed hybrid torsional vibration damper. The system under investigation consists of a rotor with attached hybrid torsional MR damper subjected to an external harmonic torque. The CPVA has been connected to the cylindrical housing of the MR damper. Different cases have been investigated including: 1- Rotor system without any damper, 2- Rotor system with only CPVA, 3- Rotor system with only torsional MR damper and 4- Rotor system with the hybrid torsional damper. Results for each case have been illustrated and compared against one another.Copyright © 2014 by ASME
2 citations
01 May 2014
TL;DR: In this paper, the authors presented results from analytical investigation of rotor systems integrated with CPVA, where the system under investigation is modeled as a rotating disk attachedwith CPVA in which the disk is subjected to an external simple harmonic torque.
Abstract: Centrifugal Pendulum Vibration Absorber (CPVA) has been effectively used inrotating and reciprocating machines to control torsional vibrations passively Thisresearch presents results from analytical investigation of rotor systems integratedwith CPVA The system under investigation is modeled as a rotating disk attachedwith CPVA in which the disk is subjected to an external simple harmonic torqueMathematical model of a rotor fitted with a CPVA has been formulated and theequations of motion are derived using Lagrange principle The effect of gravity due toCPVA operating in a vertical plane with a horizontal shaft has been considered in theformulation The results are also compared with those based on CPVA operating in ahorizontal plane in which the effect of gravity has been neglected Moreover,softening nonlinear behavior of the pendulum and its effect on the natural frequencyof the system has been investigated