Concepts for a theoretical and experimental study of lifting rotor random loads and vibrations, Phase 2

A comparison with NASA conducted simulator studies has shown that the approximate digital method for computing rotor blade flapping responses to random inputs, tentatively suggested in Phase I Report, gives with increasing rotor advance ratio the wrong trend. Consequently, three alternative methods of solution have been considered and are described: (1) an approximate method based on the functional relation between input and output double frequency spectra, (2) a numerical method based on the system responses to deterministic inputs and (3) a perturbation approach. Among these the perturbation method requires the least amount of computation and has been developed in two forms - the first form to obtain the response correlation function and the second for the time averaged spectra of flapping oscillations

Fuzzy Logic Controlled Microturbine Generation System for Distributed Generation

AbstractThe microturbine based Distributed Generation (DG) system are becoming the popular source of power industries due to their fuel flexibility, reliability and power quality. The microturbine generation (MTG) system is a complicated thermodynamic electromechanical system with a high speed of rotation, frequency conversion and its control strategy. In spite of several techniques to control high speed of microturbine is not accurate and reliable due to their anti-interference problem. To resolve the anti-interfacing problem, this paper investigates the fuzzy logic based speed governor for a MTG system as an alternative to nominal PI or lead-lag based controller. The development of fuzzy logic based speed governor includes input and output membership function with their respective members. The load variation on MTG system is performed using conventional and fuzzy logic controller, implemented in Matlab/simulink and results are compared with each other. The simulation result shows that, the performance improvement of fuzzy logic governor over a nominal governor based MTG system

Concepts for a theoretical and experimental study of lifting rotor random loads and vibrations. Phase 5A: Effects of torsional blade flexibility on single blade random gust response statistics

Quasi-steady aerodynamics were assumed, as well as a torsion mode where the amplitude is proportional to the distance from the rotor center. Aerodynamic torsional moment inputs are limited to the region of reverse flow where the aerodynamic center and the section center of gravity are separated by half the blade chord. Thus negligible effects of blade torsional flexibility are obtained for rotor conditions with negligible reverse flow effects. Numerical examples refer to conditions with 1.6 rotor advance ratio. It was found that the random flapping response is only moderately affected by torsional flexibility. However large random torsional loads and deflections occur even if flapping is completely suppressed. The coupling of the actual flapping motion into the blade torsional motion produces a substantial increase in the random torsional loads or deflections

Exploring Fuzzy Set Concept in Priority Theory for Maintenance Strategy Selection Problem

This paper proposes and presents a different approach of choosing an appropriate maintenance strategy using Saaty’s priority theory and fuzzy sets. As per the priority theory, weights are assigned to the decision criteria via pair wise comparison of criteria. Basic three types of maintenance strategies specifically corrective maintenance, preventive maintenance and predictive maintenance and eight maintenance decision criteria namely low maintenance cost, improved reliability, improved safety, high product quality, minimum inventory, return on investment, acceptance by labor, enhanced competitiveness have been considered to evaluate the most favorable strategy. Instead of usual practice of considering single value for “intensity of importance” factor, more appropriate triangular fuzzy numbers are used to represent it. A different approach using fuzzy arithmetic (α-cuts) in priority theory for the above stated problem has been investigated in this paper

Computational evaluation of small molecule inhibitors of RGS4 to regulate the dopaminergic control of striatal LTD

Parkinson’s disease is a neurodegenerative disease which is the result of the degradation of the dopaminergic neurons in the substantia nigra pars compacta, leading to a disregulation of thalamocortical circuits. Traditional treatment involves the use of levodopa which increases the dopamine level in the striatum. There is a need for alternative non-dopamine therapy to prevent the side effects of the conventional drugs used. Recently small molecule inhibitors of RGS have become the prime candidates in studies related to regulating RGS by binding to its allosteric site and thus changing its structure. Through the docking studies we observed that these small molecule modulators of RGS4 make stable complexes with RGS4 when compared to native RGS4. The Gq(alpha)–GS4–rug complexes are less stable. The increase in flexibility of the RGS4–rug complex could be the reason for the inability of the RGS4–rug complex to bind to the G protein. In our docking results, CCG63802 formed the most promising drug as a RGS4 inhibitor as it formed the most stable complex with RGS4 and also formed the least stable complex, Gq(alpha)–RGS4–CCG63802 complex. In our studies we evaluated the therapeutic potential of the small molecule inhibitors to provide a prospective treatment for Parkinson’s disease.Keywords: RGS4 inhibitor; Parkinson disease; Flexibility; MGlu receptors; Neural plasticityThe Egyptian Journal of Medical Human Genetics (2013) 14, 135–14

Active faulting in apparently stable peninsular India: Rift inversion and a Holocene-age great earthquake on the Tapti Fault

We present observations of active faulting within peninsular India, far from the surrounding plate boundaries. Offset alluvial fan surfaces indicate one or more magnitude 7.6–8.4 thrust-faulting earthquakes on the Tapti Fault (Maharashtra, western India) during the Holocene. The high ratio of fault displacement to length on the alluvial fan offsets implies high stress-drop faulting, as has been observed elsewhere in the peninsula. The along-strike extent of the fan offsets is similar to the thickness of the seismogenic layer, suggesting a roughly equidimensional fault rupture. The subsiding footwall of the fault is likely to have been responsible for altering the continental-scale drainage pattern in central India, and creating the large west-flowing catchment of the Tapti river. A pre-existing sedimentary basin in the uplifting hangingwall implies the Tapti Fault was active as a normal fault during the Mesozoic and has been reactivated as a thrust, highlighting the role of pre-existing structures in determining the rheology and deformation of the lithosphere. The slip sense of faults and earthquakes in India suggests that deformation south of the Ganges foreland basin is driven by the compressive force transmitted between India and the Tibetan Plateau. The along-strike continuation of faulting to the east of the Holocene ruptures we have studied represents a significant seismic hazard in central India.RCUKDOI: 10.1002/2014JB011294This is the final version of the following article: A. Copley, S. Mitra, R.A. Sloan, S. Gaonkar, and K. Reynolds, Active faulting in apparently stable peninsular India: rift inversion and a Holocene-age great earthquake on the Tapti Fault, Journal of Geophysical Research, which is also available at http://dx.doi.org/10.1002/2014JB011294

Computerised control and data acquisition for corrosion experiments

Electrochemical measurement of corrosion involves imposition of electrical perterbation in the form of potential or current on the test specimen and measuring its response. A potentiostat is most frequently used for this purpose. The present paper describes a menu driven user friendly software developed for corrosion analysis by interfacing the potentiostat with PC-AT. The system was developed around a laboratory developed potentiostat and a PC/AT 486.The interface between the two was devel-oped using a PC plug in PCL 208A card with nominal speci-fications : AD 16 ch., DA 2ch, res 12 bits, max. frequency 100 KHz. The DA channels were modified for bipolar output and fine turfing of potential. Corrosion rates are measu-red by (i) linear polarisation, (ii) Tafel analysis and (iii) increasing pulse polarisation. The corrosion rate is calculated using Stern Greary equation with Rp measured from the polarisation data and known tafel slopes. Alterna-tively it is calculated using a nonlinear least square alg-orithm. Besides corrosion measurement the system is also used for other experiments like potentiodynamic polari-sation, pitting, cyclic voltametry, EPR and transients. The specification for the present system are : control potential range ±2V, resolution 0.488 mV, current sensit-ivity 0.1 uA, scan rate 0.26 uVlsec to 20 Vlsec, pulse potential 1.2 mV to 5V, pulse time 250 ms. to 72 mins. Completely arbitrary waveform can be generated and imposed on specimens. The software has facility for preview of potential wafeform, simultaneous display of acquired potential/current data, drawing of lines and tangents, data viewing and editing and calculation of different corrosion and electrochemical parameters

Aerosol Infection Model of Tuberculosis in Wistar Rats

We explored suitability of a rat tuberculosis aerosol infection model for investigating the pharmacodynamics of new antimycobacterial agents. Infection of rats via the aerosol route led to a reproducible course of M. tuberculosis infection in the lungs. The pulmonary bacterial load increased logarithmically during the first six weeks, thereafter, the infection stabilized for the next 12 weeks. We observed macroscopically visible granulomas in the lungs with demonstrable acid-fast bacilli and associated histopathology. Rifampicin (RIF) at a dose range of 30 to 270 mg/kg exhibited a sharp dose response while isoniazid (INH) at a dose range of 10 to 90 mg/kg and ethambutol (EMB) at 100 to 1000 mg/kg showed shallow dose responses. Pyrazinamide (PZA) had no dose response between 300 and 1000 mg/kg dose range. In a separate time kill study at fixed drug doses (RIF 90 mg/kg, INH 30 mg/kg, EMB 300 mg/kg, and PZA 300 mg/kg) the bactericidal effect of all the four drugs increased with longer duration of treatment from two weeks to four weeks. The observed infection profile and therapeutic outcomes in this rat model suggest that it can be used as an additional, pharmacologically relevant efficacy model to develop novel antitubercular compounds at the interface of discovery and development