Effect of Noise on Patterns Formed by Growing Sandpiles

We consider patterns generated by adding large number of sand grains at a single site in an abelian sandpile model with a periodic initial configuration, and relaxing. The patterns show proportionate growth. We study the robustness of these patterns against different types of noise, \textit{viz.}, randomness in the point of addition, disorder in the initial periodic configuration, and disorder in the connectivity of the underlying lattice. We find that the patterns show a varying degree of robustness to addition of a small amount of noise in each case. However, introducing stochasticity in the toppling rules seems to destroy the asymptotic patterns completely, even for a weak noise. We also discuss a variational formulation of the pattern selection problem in growing abelian sandpiles.Comment: 15 pages,16 figure

ASSESSMENT OF DRINKING WATER QUALITY IN TRIBAL DOMINATED VILLAGES OF BARKAGAON, HAZARIBAG, JHARKHAND, INDIA

Water is most essential component for the survival of any kind of life on the planet Earth. Quality and quantity of water at any place play a vital role in health, wealth and prosperity of life. Geogenic contaminants including fluoride have affected ground water in more than 200 districts of 19 states of India. Fluoride is one of the most essential elements for calcification of bones and teeth where as excess intake (above 1.5 mg/lit.) may cause skeletal, non skeletal and dental fluorosis. Drinking water samples from five tribal dominated villages of Barkagaon (230 52′ 5′′ N latitude and 850 14′ 15′′ E longitude), Hazaribag, Jharkhand, India were taken fortnightly from hand pump during rainy, winter and summer seasons (July 2011- June 2012) for fluoride analysis as per standard protocol of APHA (2005) and the results showed that all the samples contained higher concentration. The highest average concentration of fluoride was recorded in Bhurkundwa village (3.84±0.8 mg/lit.) where as it was lowest in Aswa village (1.89± 0.8 mg/lit). We have studied the impact of fluoride among 426 school children (06-16 yrs) with reference to Dean’s Index for dental fluorosis which reveals that almost 87% were suffering from dental fluorosis. The results clearly indicate that the dental fluorosis among children is directly related to fluoride concentration in drinking water. Our opinion regarding the higher fluoride concentration in the study area is due to excess mineral exploration. Thus necessary steps must be taken to supply the quality drinking water to the locality for the maintenance of the health of tribal people

Water Loss Under Hot Ambient Temperatures

Male 4 rates were ambient temperature (40 degree,42 degree, and 44 degree calcius) for different durations of time upto a maximum of 3 hours. It was observed that there was a rapid loss in body weight accompanied by considerable increase in body temperature of the animals during the first hour of exposure. Thereafter the rate of body weight loss and increase in body temperature were slow till the end of observation period. Intolerance to heat appears to be more correlated with critical body temperature rather than the extent of dehydration

Photovoltaic Grid Integrated System Based on MPPT Technique By using MATLAB/SIMULINK

This paper provides an easy accurate method of modeling photovoltaic arrays. The methodis comfortable to obtain the parameters of the array model using information from the datasheet. The electric system consists of a photovoltaic module (PV) module, a DC/DC converter and a DC/AC converter to release the grid connection. A maximum-power point tracking (MPPT) technique is used to extract maximum amount of power from solar cells. The photovoltaic model is established using basic circuit equations of the Photovoltaic (P-V) cells including the effects of solar radiation and temperature changes. One-diode equivalent circuit is used in order to study I-V and P-V characteristics of a typical 36W solar module and draws results according to values changes of the temperature and solar irradiation which is observed in MATLABSIMULINK. Hence, the P-V module has nonlinear characteristics, and the Photovoltaic system characteristic curves such as current-voltage (I-V) and power-voltage (P-V) characteristics are drawn according to values change in temperature and solar radiation which is observed in MATLAB-SIMULINK

Emergence of quasi-units in the one dimensional Zhang model

We study the Zhang model of sandpile on a one dimensional chain of length $L$, where a random amount of energy is added at a randomly chosen site at each time step. We show that in spite of this randomness in the input energy, the probability distribution function of energy at a site in the steady state is sharply peaked, and the width of the peak decreases as ${L}^{-1/2}$ for large $L$. We discuss how the energy added at one time is distributed among different sites by topplings with time. We relate this distribution to the time-dependent probability distribution of the position of a marked grain in the one dimensional Abelian model with discrete heights. We argue that in the large $L$ limit, the variance of energy at site $x$ has a scaling form $L^{-1}g(x/L)$, where $g(\xi)$ varies as $\log(1/\xi)$ for small $\xi$, which agrees very well with the results from numerical simulations.Comment: 7 pages, 3 figures, RevTex

An Efficient Power Control Technique for High-Frequency Resonant Inverter in Induction Heating System

An efficacious and reliable power control technique has been developed which can be used to regulate the output power of a high-frequency full bridge series resonant inverter (HF-FBSRI) in an induction heating (IH) system. In this paper, a modified buck-boost converter is presented to control the DC link/bus voltage which maintains the IH system under resonant mode and optimizes the performance of the IH system. Controlled DC link/bus voltage has been applied to this HF- FBSRI to control the average output power in the IH system. Using this aimed control technique, a wide range of output powers has been controlled and consistent performance of the IH system has been achieved. ZVS switching technique has been used to reduce the switching losses. Varying average power has been obtained at different duty cycles ranging from 0.2 to 0.8 with variable DC link voltage and it has been corroborated using PSIM environment for an IH system rated at 5500W

Spectral properties of zero temperature dynamics in a model of a compacting granular column

The compacting of a column of grains has been studied using a one-dimensional Ising model with long range directed interactions in which down and up spins represent orientations of the grain having or not having an associated void. When the column is not shaken (zero 'temperature') the motion becomes highly constrained and under most circumstances we find that the generator of the stochastic dynamics assumes an unusual form: many eigenvalues become degenerate, but the associated multi-dimensional invariant spaces have but a single eigenvector. There is no spectral expansion and a Jordan form must be used. Many properties of the dynamics are established here analytically; some are not. General issues associated with the Jordan form are also taken up.Comment: 34 pages, 4 figures, 3 table

Farming of cobia, Rachycentron canadum (Linnaeus 1766) in open sea floating cages in India

Experiments on culture and growth performance of cobia were undertaken in marine cages installed in the Arabian Sea off Karwar on the south-west coast of India. Hatchery produced cobia fingerlings were stocked at two densities of 3.5 fish cubic m-1 and 14.1 fish cubic m-1 in circular HDPE cages. Mean weight and specific growth rate (SGR) of cobia stocked @ 3.5 fish cubic m -1 were 10.5 kg and 2.2% day-1, respectively, at 300 days of culture (DOC). Cobia stocked @ of 14.1 fish cubic m-1 attained an average weight of 3.68 kg and SGR of 1.9% day-1 at 300 DOC. SGR was found to be positively correlated with water temperature and salinity during the culture period. No significant variation was found in SGR and feed conversion ratio of cobia stocked at two different densities. However, absolute growth rate, relative growth rate and mean weight of cobia varied significantly between the two groups