Design and Implementation of Position Estimator Algorithm on Voice Coil Motor

Voice Coil Motors (VCMs) have been an inevitable element in the mechanisms that have been used for precise positioning in the applications like 3D printing., micro-stereolithography., etc. These voice coil motors translate in a linear direction and require a high accuracy position sensor that amounts for a major part in the budget. In this research work., an effort has been made to design and implement an algorithm that would predict the displacement of VCM and eliminate the need of high cost sensors. VCM was integrated with dSPACE DS1104 R&D controller via linear current amplifier (LCAM) which acts as a driver circuit for VCM. Sine input was given to VCM with various amplitude and frequency and the corresponding displacement is measured by using linear variable differential transformer (LVDT). The position estimator algorithm is also implemented at the same time on VCM and its output is compared with that of LVDT. It is observed that there is 97.8 % accuracy in between algorithm output and LVDT output. Further., PID controller is used in integration with the novel algorithm to minimize the error. The estimator algorithm is tested for various amplitudes and frequencies and it is found that it has a very good agreement of 99.2% with the actual displacement measured with the help of LVDT

Landing of ‘Flying Gurnard’ in Mumbai

A rare fish ‘flying gurnard’ was landed by a trawler operating in 70-100 m depth in the sea off Mumbai. The species was identified as Dactyloptena peterseni (Nystrom, 1887) and it is reported for the first time along the Indian coast

Study of drug prescription pattern in diarrhoea patients admitted to paediatric ward in a government tertiary care hospital in Maharashtra, India

Background: World Health Organization (WHO) has defined diarrhoea as, ‘the passage of loose stools by an individual, at least thrice a day or more frequently than normal’. It is most commonly caused by intestinal infection, mainly viral. Every year there are about 2 billion cases of diarrhoea worldwide, a second leading cause of mortality in children below the age of 5 years. WHO estimated that antibiotic treatment was necessary in only one in twenty cases of childhood diarrhoea. Yet huge resources are currently spent on anti-diarrhoeal drugs annually, most rendered useless or harmful. This study was proposed to evaluate the utilization pattern of drugs prescribed for diarrhoea in children, in a government tertiary care hospital in Maharashtra.Methods: This cross-sectional observational study was carried out in the paediatric ward of government tertiary care hospital, Maharashtra. All patients of age less than twelve years with diarrhoea admitted to paediatric ward within the study period of January 2015 - June 2016 were included in the study. Patients older than twelve years or admitted with other gastrointestinal diseases or co-mordbid conditions were excluded. Statistical analysis was done using descriptive statistics.Results: Majority of the patients admitted were males and more than half the patient population were in the age group of less than or equal to 3 years. Polypharmacy was found to be present in the prescribing pattern, with average, more than 4 drugs prescribed for diarrhoea treatment, in each prescription. Majority drugs were prescribed using brand names and parenteral route. Use of antibiotics was also found to be inappropriate in majority of the cases.Conclusions: The study highlighted the importance of drug utilisation studies and pointed out inappropriate drug prescribing trends for diarrhoea cases in a tertiary care hospital in Maharashtra

Great Inequality of Jupiter and Saturn I: The Planetary Three Body Problem, Heliocentric development by Lagrange multipliers, Perturbation Theory Formulation

In this paper, we undertake to present a self-contained and thorough analysis of the gravitational three body problem, with anticipated application to the Great Inequality of Jupiter and Saturn. The analysis of the three body Lagrangian is very convenient in heliocentric coordinates with Lagrange multipliers, the coordinates being the vector-sides $\vec{r}_i,\,i=1,2,3$ of the triangle that the bodies form. In two dimensions to begin with, the equations of motion are formulated into a dynamical system for the polar angles $\theta_i$, angular momenta $\ell_i$ and eccentricity vectors $\vec{e}_i$. The dynamical system is simplified considerably by change of variables to certain auxiliary vector $\vec{f}_i=\hat{r}_i+\vec{e}_i$. We then begin to formulate the Hamiltonian perturbation theory of the problem, now in three dimensions. We first give the geometric definitions for the Delaunay action-angle variables of the two body problem. We express the three body Hamiltonian in terms of Delaunay variables in each sector $i=1,2,3$, revealing that it is a nearly integrable Hamiltonian. We then present the KAM theory perturbative approach that will be followed in future work, including the modification that will be required because the Hamiltonian is degenerate

Maintenance, Repair, and Overhaul Performance Indicators for Military Aircraft

Modern day military and commercial aircraft systems are an integration of a large number of sub-systems and components. Each of these systems has different reliability characteristics and different probability distributions governing their failure rates. Space constraints and structural layout of the aircraft govern the position of each component. The accessibility, reliability, and snag diagnostic-ability determines the maintainability of the aircraft. The peculiarities involved in aircraft maintenance are discussed and performance measurement indices for O, I and D level maintenance are presented in this paper. These performance measurement indices are intended for use by aircraft maintenance managers for instituting process improvements for achieving best flight and maintenance safety records, improve operational availability of the aircraft and reduce costs.Defence Science Journal, 2012, 62(2), pp.83-89, DOI:http://dx.doi.org/10.14429/dsj.62.88

Application of RSM to optimise single locking cotton feeder for enhancing ginning efficiency of double roller gin

Spike cylinder single locking cotton feeder has been developed and optimized to enhance the ginning efficiency of doubleroller (DR) gin. The feeder is developed with an aim to unlock the cotton bolls and maintain constant feeding rate of individuallocules at the ginning point of DR gin. Spike cylinder speed and cotton moisture content are optimized by using responsesurface methodology. Ginning efficiency of DR gin is improved with the use of developed feeder. Quadratic models forprediction of ginning output and specific energy and linear model for prediction of reduction in bulk density are generated byusing response surface methodology following central composite design that show excellent agreement with the experimentalvalues. Multiple response analysis shows the optimum level of moisture content (7.49%) and spike cylinder speed (317 rpm)with desirability of 0.904695 by maximizing the output and minimizing the specific energy. The ginning output, cleaningefficiency and reduction in bulk density are increased by 23.25%, 16% and 30.5% respectively, whereas the specific energy isdecreased by 12% without any adverse effect on fibre quality. Colour grade of the cotton improves from middling to strictmiddling. Thus, the developed feeder would be highly useful for cotton ginneries