435 research outputs found

    PEMBUATAN PROTOTIPE OTOMATISASI PENGOLAHAN DATA KAFE DAN KARAOKE BERBASIS MIKROKONTROLER AVR

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    Karaoke and café are places which often be visited by customer. This places are very busy and potentially robbing can be happenned. To manage karaoke and café easier it is neededautomation, so it can work effective and efficient. The objective of this final project report isto make a managing automation prototype of Karaoke and café data based on AVR microcontroller. A managing automation prototype of Karaoke and café data based on AVR microcontroller has been made. Generally detection of managing automation prototype of Karaoke and café data based on AVR microcontroller has designed use 16/32 Atmega, LCD, 4x4 keypad, DC motor, L293D IC, and push button. For ordering prototype, microcontroller receives input from keypad, than the result of microcontroller process will show by LCD output and seven segments. For automatic order serving, microcontroller receives input from push button, than microcontroller output becomes L293D IC input. The L293D IC outputs control DC motor. At door security, microcontroller processeson LCD output and IC L293D, IC L293D control DC motor. At billing karaoke, microcontroller receives input from the push button, and outputwill be displayed as seven segments. This prototype makes managing karaoke and cafe easier, save the time and energy. It can be concluded that m anaging automation prototype of karaoke and café data based on AVR microcontroller can be used as real managing automation prototype of karaoke and café data

    Inverse flux quantum periodicity of magnetoresistance oscillations in two-dimensional short-period surface superlattices

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    Transport properties of the two-dimensional electron gas (2DEG) are considered in the presence of a perpendicular magnetic field BB and of a {\it weak} two-dimensional (2D) periodic potential modulation in the 2DEG plane. The symmetry of the latter is rectangular or hexagonal. The well-known solution of the corresponding tight-binding equation shows that each Landau level splits into several subbands when a rational number of flux quanta h/eh/e pierces the unit cell and that the corresponding gaps are exponentially small. Assuming the latter are closed due to disorder gives analytical wave functions and simplifies considerably the evaluation of the magnetoresistivity tensor ρμν\rho_{\mu\nu}. The relative phase of the oscillations in ρxx\rho_{xx} and ρyy\rho_{yy} depends on the modulation periods involved. For a 2D modulation with a {\bf short} period 100\leq 100 nm, in addition to the Weiss oscillations the collisional contribution to the conductivity and consequently the tensor ρμν\rho_{\mu\nu} show {\it prominent peaks when one flux quantum h/eh/e passes through an integral number of unit cells} in good agreement with recent experiments. For periods 300400300- 400 nm long used in early experiments, these peaks occur at fields 10-25 times smaller than those of the Weiss oscillations and are not resolved

    Phase Transitions of Hard Disks in External Periodic Potentials: A Monte Carlo Study

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    The nature of freezing and melting transitions for a system of hard disks in a spatially periodic external potential is studied using extensive Monte Carlo simulations. Detailed finite size scaling analysis of various thermodynamic quantities like the order parameter, its cumulants etc. are used to map the phase diagram of the system for various values of the density and the amplitude of the external potential. We find clear indication of a re-entrant liquid phase over a significant region of the parameter space. Our simulations therefore show that the system of hard disks behaves in a fashion similar to charge stabilized colloids which are known to undergo an initial freezing, followed by a re-melting transition as the amplitude of the imposed, modulating field produced by crossed laser beams is steadily increased. Detailed analysis of our data shows several features consistent with a recent dislocation unbinding theory of laser induced melting.Comment: 36 pages, 16 figure

    Shortest paths on systems with power-law distributed long-range connections

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    We discuss shortest-path lengths (r)\ell(r) on periodic rings of size L supplemented with an average of pL randomly located long-range links whose lengths are distributed according to P_l \sim l^{-\xpn}. Using rescaling arguments and numerical simulation on systems of up to 10710^7 sites, we show that a characteristic length ξ\xi exists such that (r)r\ell(r) \sim r for r>ξr>\xi. For small p we find that the shortest-path length satisfies the scaling relation \ell(r,\xpn,p)/\xi = f(\xpn,r/\xi). Three regions with different asymptotic behaviors are found, respectively: a) \xpn>2 where θs=1\theta_s=1, b) 1<\xpn<2 where 0<\theta_s(\xpn)<1/2 and, c) \xpn<1 where (r)\ell(r) behaves logarithmically, i.e. θs=0\theta_s=0. The characteristic length ξ\xi is of the form ξpν\xi \sim p^{-\nu} with \nu=1/(2-\xpn) in region b), but depends on L as well in region c). A directed model of shortest-paths is solved and compared with numerical results.Comment: 10 pages, 10 figures, revtex4. Submitted to PR

    Commensurate and Incommensurate Vortex Lattice Melting in Periodic Pinning Arrays

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    We examine the melting of commensurate and incommensurate vortex lattices interacting with square pinning arrays through the use of numerical simulations. For weak pinning strength in the commensurate case we observe an order-order transition from a commensurate square vortex lattice to a triangular floating solid phase as a function of temperature. This floating solid phase melts into a liquid at still higher temperature. For strong pinning there is only a single transition from the square pinned lattice to the liquid state. For strong pinning in the incommensurate case, we observe a multi-stage melting in which the interstitial vortices become mobile first, followed by the melting of the entire lattice, consistent with recent imaging experiments. The initial motion of vortices in the incommensurate phase occurs by an exchange process of interstitial vortices with vortices located at the pinning sites. We have also examined the vortex melting behavior for higher matching fields and find that a coexistence of a commensurate pinned vortex lattice with an interstitial vortex liquid occurs while at higher temperatures the entire vortex lattice melts. For triangular arrays at incommensurate fields higher than the first matching field we observe that the initial vortex motion can occur through a novel correlated ring excitation where a number of vortices can rotate around a pinned vortex. We also discuss the relevance of our results to recent experiments of colloidal particles interacting with periodic trap arrays.Comment: 8 figure

    Velocity-force characteristics of an interface driven through a periodic potential

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    We study the creep dynamics of a two-dimensional interface driven through a periodic potential using dynamical renormalization group methods. We find that the nature of weak-drive transport depends qualitatively on whether the temperature TT is above or below the equilibrium roughening transition temperature TcT_c. Above TcT_c, the velocity-force characteristics is Ohmic, with linear mobility exhibiting a jump discontinuity across the transition. For TTcT \le T_c, the transport is highly nonlinear, exhibiting an interesting crossover in temperature and weak external force FF. For intermediate drive, F>FF>F_*, we find near TcT_c^{-} a power-law velocity-force characteristics v(F)Fσv(F)\sim F^\sigma, with σ1t~\sigma-1\propto \tilde{t}, and well-below TcT_c, v(F)e(F/F)2t~v(F)\sim e^{-(F_*/F)^{2\tilde{t}}}, with t~=(1T/Tc)\tilde{t}=(1-T/T_c). In the limit of vanishing drive (FFF\ll F_*) the velocity-force characteristics crosses over to v(F)e(F0/F)v(F)\sim e^{-(F_0/F)}, and is controlled by soliton nucleation.Comment: 18 pages, submitted to Phys. Rev.

    Environmental Electrokinetics for a sustainable subsurface

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    International audienceSoil and groundwater are key components in the sustainable management of the subsurface environment. Source contamination is one of its main threats and is commonly addressed using established remediation techniques such as in-situ chemical oxidation (ISCO), in-situ chemical reduction (ISCR; most notably using zero-valent iron [ZVI]), enhanced in-situ bioremediation (EISB), phytoremediation, soil-washing, pump-and-treat, soil vapour extraction (SVE), thermal treatment, and excavation and disposal. Decades of field applications have shown that these techniques can successfully treat or control contaminants in higher permeability subsurface materials such as sands, but achieve only limited success at sites where low permeability soils, such as silts and clays, prevail. Electrokinetics (EK), a soil remediation technique mostly recognized in in-situ treatment of low permeability soils, has, for the last decade, been combined with more conventional techniques and can significantly enhance the performance of several of these remediation technologies, including ISCO, ISCR, EISB and phytoremediation. Herein, we discuss the use of emerging EK techniques in tandem with conventional remediation techniques, to achieve improved remediation performance. Furthermore, we highlight new EK applications that may come to play a role in the sustainable treatment of the contaminated subsurface
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