Ordering dynamics of self-propelled particles in an inhomogeneous medium

Ordering dynamics of self-propelled particles in an inhomogeneous medium in two-dimensions is studied. We write coarse-grained hydrodynamic equations of motion for coarse-grained density and velocity fields in the presence of an external random disorder field, which is quenched in time. The strength of inhomogeneity is tuned from zero disorder (clean system) to large disorder. In the clean system, the velocity field grows algebraically as $L_{\rm V} \sim t^{0.5}$. The density field does not show clean power-law growth; however, it follows $L_{\rm \rho} \sim t^{0.8}$ approximately. In the inhomogeneous system, we find a disorder dependent growth. For both the density and the velocity, growth slow down with increasing strength of disorder. The velocity shows a disorder dependent power-law growth $L_{\rm V}(t,\Delta) \sim t^{1/\bar z_{\rm V}(\Delta)}$ for intermediate times. At late times, there is a crossover to logarithmic growth $L_{\rm V}(t,\Delta) \sim (\ln t)^{1/\varphi}$, where $\varphi$ is a disorder independent exponent. Two-point correlation functions for the velocity shows dynamical scaling, but the density does not

Exploration of Mutli-Threshold Ferro-Electric FET Based Designs

The surge in data intensive applications has given rise to demand for high density storage devices and their efficient implementations. Consequently, Multi-level-cell(MLC) memories are getting explored for their promising aspects of higher storage density and lower unit storage cost. However, the multi-bit data stored in these memories need to be converted to processor compatible forms (typically binary) for processing. In this work, we have proposed an adaptable multi-level voltage to binary converter using Ferro-electric Field Effect Transistors(FeFET) capable of translating input voltage to bits. The use of FeFETs as voltage comparators simplifies the circuit and offers adaptable voltage quantization, flexible output bit-width(1/2 bits) and security feature. The circuit also employs incremental output encoding, which limits error margin to the least significant bits(LSB). The proposed 4-level to 2-bit converter circuit is demonstrated in simulation to have an input voltage range of [0 ? 3.75V] / [0 ? 2.7V] for FeFETs with 20/2000-domains respectively

Nonequilibrium Dynamics of the Complex Ginzburg-Landau Equation. I. Analytical Results

We present a detailed analytical and numerical study of nonequilibrium dynamics for the complex Ginzburg-Landau (CGL) equation. In particular, we characterize evolution morphologies using spiral defects. This paper (referred to as $\rm I$) is the first in a two-stage exposition. Here, we present analytical results for the correlation function arising from a single-spiral morphology. We also critically examine the utility of the Gaussian auxiliary field (GAF) ansatz in characterizing a multi-spiral morphology. In the next paper of this exposition (referred to as $\rm II$), we will present detailed numerical results.Comment: 21 pages, 7 figure

Surface-Directed Spinodal Decomposition: A Molecular Dynamics Study

We use molecular dynamics (MD) simulations to study surface-directed spinodal decomposition (SDSD) in unstable binary ($AB$) fluid mixtures at wetting surfaces. The thickness of the wetting layer $R_1$ grows with time $t$ as a power-law ($R_1 \sim t^\theta$). We find that hydrodynamic effects result in a crossover of the growth exponent from $\theta\simeq 1/3$ to $\theta\simeq1$. We also present results for the layer-wise correlation functions and domain length scales.Comment: 29 pages, 13 figures, submitted to PR

Entrepreneurship through Micro Finance in North East India: A Comprehensive Review of Existing Literature

Entrepreneurship on small scale is the only solution to the problems of unemployment and proper utilization of both human and non-human resources and improving the living conditions of the poor masses. The basic rationale of developing these industries are that they provide immediate large scale employment, ensure more equitable distribution of income, encourage decentralization of industries and eradicate poverty and unemployment. During the last three decades, many countries of the world have experienced the need and importance of entrepreneurship has been accepted as a strategy to achieve the twin objectives of promotion of entrepreneurship, particularly among the educated unemployed youth and also for rapid industrialization in the economy. The main object of this paper is to study the existing literature on entrepreneurship through Micro finance-SHG linkage in India in general and NER in particular. The analysis of this study is based on secondary sources. Efforts are also made in this paper to analyze the role of micro finance through SHGs in the promotion and development of entrepreneurship. This paper examines the different approaches of entrepreneurship and also explains the different key areas of micro enterprise development. Finally, this paper highlights the problems of micro, rural and women entrepreneurs and also suggested some specific measures based on the survey of existing literature, for the promotion of these industries in the country

Epidemic Spreading with External Agents

We study epidemic spreading processes in large networks, when the spread is assisted by a small number of external agents: infection sources with bounded spreading power, but whose movement is unrestricted vis-\`a-vis the underlying network topology. For networks which are `spatially constrained', we show that the spread of infection can be significantly speeded up even by a few such external agents infecting randomly. Moreover, for general networks, we derive upper-bounds on the order of the spreading time achieved by certain simple (random/greedy) external-spreading policies. Conversely, for certain common classes of networks such as line graphs, grids and random geometric graphs, we also derive lower bounds on the order of the spreading time over all (potentially network-state aware and adversarial) external-spreading policies; these adversarial lower bounds match (up to logarithmic factors) the spreading time achieved by an external agent with a random spreading policy. This demonstrates that random, state-oblivious infection-spreading by an external agent is in fact order-wise optimal for spreading in such spatially constrained networks

Assessment of Groundwater Hazards in a Coastal District of Gujarat, India

Jamnagar district of Gujarat is having 355 km long irregular coast line. The district is bounded by Gulf of Kachchh in the north and Arabian Sea in the west and southwest. The precipitation in the area is low and climate is semi arid. Rivers flowing in the area are ephemeral. Ground water occurs in unconfined and semi-confined state. Major central part of the area is occupied by Deccan basalt, western part by marine Tertiary rocks, northern and western coastal area by Quaternary sediments. In general, ground water in Deccan basalt is fresh whereas in Tertiary and Quaternary sediments it is brackish due to inherent salinity as well as sea water intrusion. Miliolite limestone in this area forms good aquifer. Groundwater hazards in the area are mainly related with the inherent salinity of rocks/ sediments, sea water ingress in the coastal area and chemical pollution. Brackish ground water, toxic element (Pb, Ni) and radicals (SO4--, NO3-, Cl- and Fluoride) zones have been identified and delineated based on the integrated GIS study. About 181 villages of the district are affected by high TDS, 39 villages by high Fluoride and 2 villages both by high TDS and Fluoride