Non-ideal Parameters Research Articles

Investigation of device imperfection influence on measurement results in beamsplitter-based quantum random number generation schemes

Quantum random number generation allows acquiring true random numbers which can be used in applications that require a high degree of randomness. This paper assesses the influence of non-ideal scheme parameters on measurement results in two quantum random number generation schemes: based on laser radiation splitting, and using vacuum fluctuations.

Predicting sulphate adsorption/desorption in forest soils: Evaluation of an extended Freundlich equation

Sulphate adsorption and desorption can delay the response in soil acidity against changes in acid input. Here we evaluate the use of an extended Freundlich equation for predictions of pH-dependent SO4 adsorption and desorption in low-ionic strength soil systems. Five B horizons from Spodosols were subjected to batch equilibrations at low ionic strength at different pHs and dissolved SO4 concentrations. The proton coadsorption stoichiometry (η), i.e. the number of H+ ions co-adsorbed for every adsorbed SO42− ion, was close to 2 in four of five soils. This enabled the use of a Freundlich equation that involved only two adjustable parameters (the Freundlich coefficient KF and the non-ideality parameter m). With this model a satisfactory fit was obtained when only two data points were used for calibration. The root-mean square errors of log adsorbed SO4 ranged from 0.006 to 0.052. The model improves the possibility to consider SO4 adsorption/desorption processes correctly in dynamic soil chemistry models.

Self-similar solutions and converging shocks in a non-ideal gas with dust particles

In this paper, we have used the Lie group of transformations and obtained the whole range of self-similar solutions to the problem of propagation of shock waves through a non-ideal, dusty gas. The conditions essential for the existence of similarity solutions for a strong shock are discussed. The problem of imploding (converging) shock wave is also worked out and the effects of the mass concentration of the dust particles, ratio of the density of solid particles to that of initial density of the medium, the relative specific heat and the effect of the non-ideal parameter, on the shock formation has been studied in detail.

Singular surface and steepening of waves in a non-ideal gas with dust particles

In this paper, the singular surface theory has been used to study different modes of wave propagation and its culmination into discontinuities at the wave fronts in a plane, cylindrically and spherically symmetric flow of a non-ideal dusty gas. The transport equation for the jump discontinuity has been obtained. The effects of mass fraction of solid particles, ratio of specific heats and the ratio of species densities on shock formation have been studied in detail. The effect of non-ideal parameter on the formation of shocks has also been investigated.

Mathematical modelling of ideal and non-ideal continuous stirred tank bioreactor using simulated solution

BACKGROUND Chemostats are characterized by an increase in viscosity of the reaction broth and are prone to non-ideality. The present study is mainly focused on the identification of non-idealities, namely dead zone and bypassing of a real chemostat or continuous stirred tank bioreactor. RESULTS Experimental studies were conducted in non-reactive mode to study the hydrodynamic characteristics of a real chemostat involving Lactobacillus sp. isolated from Indian curd. The influence of change of relative viscosity on non-ideality parameters was studied. A simulated solution of PVA having the same viscosity range as the growth medium of Lactobacillus sp. were used to understand the hydrodynamic behavior of the reactor by conducting residence time distribution (RTD) experiments in non-reacting mode. Both steady and unsteady state analyses have been carried out with variation of the two main process parameters, namely dilution rate and substrate concentration. CONCLUSION A clear portrait of the comparison between non-ideal and ideal systems has been cited here, and it was observed that the real or non-ideal system lags behind the ideal one in many aspects. The present study adds to the knowledge of biochemically reacting systems. © 2014 Society of Chemical Industry

On the ultracold plasma evolution

The time evolution of the Coulomb system whose initial total energy is zero is considered. The solution for a system of 2000 particles in the range of 8000 inverse plasma frequencies was obtained by themolecular dynamicsmethod. It is shown that under conditions typical of experiments with ultracold plasma the nonideality parameter of the plasma cannot reach large values due to recombination heating, and the relaxation process itself is not described within the conventional model of three-body recombination.

On the structure of MHD shock waves in a viscous non-ideal gas

The structure of one-dimensional magnetohydrodynamics (MHD) shock waves is studied using the Navier–Stokes equations for the non-ideal gas phase. The exact solutions are obtained for the flow variables (i.e. particle velocity, temperature, pressure and change-in-entropy) within the shock transition region. The equation of state for a non-ideal gas is considered as given by Landau and Lifshitz. The effects of the non-idealness parameter and coefficient of viscosity of the gas are analysed on the flow variables assuming the magnetic field having only constant axial component. The findings confirm that the thickness of MHD shock front increases with decreasing values of the non-idealness parameter.

Similarity solution for the flow behind a shock wave in a non-ideal gas with heat conduction and radiation heat-flux in magnetogasdynamics

The propagation of a spherical (or cylindrical) shock wave in a non-ideal gas with heat conduction and radiation heat-flux, in the presence of a spacially decreasing azimuthal magnetic field, driven out by a moving piston is investigated. The heat conduction is expressed in terms of Fourier’s law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient αR are assumed to vary with temperature and density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. The shock wave moves with variable velocity and the total energy of the wave is non-constant. Similarity solutions are obtained for the flow-field behind the shock and the effects of variation of the heat transfer parameters, the parameter of the non-idealness of the gas, both, decreases the compressibility of the gas and hence there is a decrease in the shock strength. Further, it is investigated that with an increase in the parameters of radiative and conductive heat transfer the tendency of formation of maxima in the distributions of heat flux, density and isothermal speed of sound decreases. The pressure and density vanish at the inner surface (piston) and hence a vacuum is form at the center of symmetry. The shock waves in conducting non-ideal gas with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of central part of star burst galaxies, nuclear explosion, chemical detonation, rupture of a pressurized vessels, in the analysis of data from exploding wire experiments, and cylindrically symmetric hypersonic flow problems associated with meteors or reentry vehicles, etc. The findings of the present works provided a clear picture of whether and how the non-idealness parameter, conductive and radiative heat transfer parameters and the magnetic field affect the flow behind the shock front.

Effect of nonideality on the collisional recombination coefficient in an ultracold plasma

The effect of nonideality on the dependence of the collisional recombination coefficient α in an ultracold plasma on the temperature T e and density n e of electrons is discussed. It has been shown that the dependence of the recombination coefficient on the density and temperature α − n e 2 T e −9/2 characteristic of a weakly nonideal plasma is transformed to α − n e 1.2 T e −2 when the ratio of the potential energy to the kinetic energy of an electron (nonideality parameter) reaches unity. As the nonideality parameter increases, the temperature dependence disappears and the density dependence becomes n e 1/2 . The existing theoretical results for various physical models have been analyzed and compared to the experimental data.

Self-similar Cylindrical Ionizing Shock Waves in a Rotational Axisymmetric Non-ideal Gas with Radiation Heat Flux

Similarity solutions are obtained for one-dimensional adiabatic flow behind a gas-ionizing cylindrical shock wave propagating in a rotational axisymetric non-ideal gas with radiation heat flux, in presence of an azimuthal magnetic field. The electrical conductivity in the medium ahead of the shock is assumed to be negligible, which becomes infinitely large after passage of the shock . The ambient medium is considered to have variable axial velocity component in addition to the variable azimuthal velocity. In order to obtain the similarity solutions, the initial density of the medium is assumed to be constant and the initial angular velocity to be obeying a power law and to be decreasing as the distance from the axis increases . Effects of an increase in the value of the parameter of non-idealness of the gas, in the value of radiation parameter and in the value of the index for variation of azimuthal velocity of the ambient medium ( or in the value of the index for variation of the ambient magnetic field ) on the shock propagation are investigated. It is observed that the non-idealness of the gas or radiation heat-flux has decaying effect on the shock wave.

Investigation of Elastic Modulus of Xanthan and Locust Bean Gum at Different Concentrations of Mixture Using Cascade Model

Small amplitude oscillatory shear tests were performed to measure the elastic modulus of 1:1 xanthan–locust bean gum (X/L) mixed gels prepared with different total polymer concentrations (C = 0.1% to 3%). The critical concentration of X/L mixture was determined to be 0.15%. Based on the elasticity exponent (t) values, the concentration–modulus power–law relationship suggested the existence of two concentration regimes – a low concentration regime (0.15 ≤ C ≤ 0.5%) with tlow = 3.88 and a high concentration regime (0.5 ≤ C ≤ 3.0%) with thigh = 1.47. The elastic active network chain of X/L mixed gels was determined by the cascade model, and compared with the similar calculation based on the classical rubber elastic theory. The cascade model clearly showed the existence of nonideality parameter and enthalpic contribution to the X/L mixed gel. Practical applications The concentration dependence at the highest interaction might be useful for developing highly concentrated xanthan and locust bean gum mixture gels. Most studies of xanthan and locust bean gum mixtures focused only on the lower concentration regime. In this study the modulus at a higher concentration increased but eventually saturated.

Thermodynamics of aqueous polyethylene-glycol (PEG) solutions at 298.15 K: Activity, activity coefficients and application of molecular theories

Osmotic coefficients measured by vapor pressure osmometry are reported for aqueous polyethylene-glycol (PEG-400, PEG-1000, and PEG-4000) solutions. The derived properties such as activity and activity coefficients have been studied as a function of solute concentration. These data along with the partial molar volume data have been analyzed with the help of molecular theories such as Flory–Huggins, McMillan–Mayer, and Kirkwood–Buff. The application of these theories enabled us to obtain second virial coefficients of PEG's, the number of binding sites, χ12 (Flory–Huggins interaction parameter), and the Kirkwood–Buff (KB) integrals, defined by the equation: Gij=∫0∞(gij−1)4πr2dr. The highlight of the work is the observation that microheterogeneity in solution increases as the chain length of solute molecule increases [estimated through mean square concentration fluctuation N〈(Δx)2〉 and non-ideality (F) parameters], confirming the concept of solute association through hydrophobic interactions in aqueous solutions.

Study on Signal Integrity Simulation for High Speed Serial Rapid IO

With the increases of signal transmission rate in digital systems, the signal integrity becomes increasingly important in high-speed circuit design. During the hardware design of high-speed serial Rapid IO, signal integrity simulation of 5Gbps high-speed serial bus had been carried out by using Channel Analysis tools. Reliable data was formed by effectively analysis and evaluation of pre-simulation, the signal quality of high-speed serial Rapid IO was verified by post-simulation. The non-ideal design parameters were optimized by referring to the effective data obtained in pre-simulation. Signal quality has been greatly improved by parameters optimization. Signal integrity simulation analysis and verification of serial Rapid IO provides strong support for the design and significantly improves the efficiency of hardware design.

Self-similar flow behind a spherical shock wave in a non-ideal dusty gas under a gravitational field: Isothermal flow

Similarity solutions are obtained for one-dimensional unsteady isothermal flow of a dusty gas behind a spherical shock wave with time dependent energy input. The dusty gas is assumed to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. It is assumed that the equilibrium flow-conditions are maintained, and the viscous stress and heat conduction of the mixture are negligible. The medium is taken to be under the influence of the gravitational field due to a heavy nucleus at the origin (Roche model). The total energy of the flow-field behind the shock is increasing. The effects of an increase in the mass concentration of solid particles, the ratio of the density of the solid particles to the initial density of the gas, the gravitational parameter (or shock Mach number), and the parameter of non-idealness of the gas in the mixture, are investigated. It is shown that due to presence of gravitational field the isothermal compressibility of the medium and the flow-variables increases and the shock strength decreases. A comparison has also been made between the medium with and without gravitational field. The shock waves in dusty medium can be important for description of star formation, shocks in supernova explosions, etc.

7-(Dimethylamino)coumarin-3-carbaldehyde and Its Phenylsemicarbazone: TICT Excited State Modulation, Fluorescent H-Aggregates, and Preferential Solvation

The photophysical properties of 7-(dimethylamino)coumarin-3-carbaldehyde 3 and its phenylsemicarbazone 4 were investigated in solvents of various polarity and in differing solvent mixtures. The different fluorescent quantum yield (ΦF) behavior of 3 and 4 in highly polar solvents is discussed in terms of Twisted Intramolecular Charge-Tranfer (TICT) state formation and the specific solute-solvent interactions. Because of the weak intermolecular hydrogen bonding ability of both the radiative ICT and nonradiative TICT excited state of 3 and the linear steep decrease in ΦF from a medium to high polarity region, coumarin 3 could be a useful polarity probe for microenvironments containing hydrogen bonding groups. Compared to 3, coumarin 4 exhibits the highest ΦF values in highly polar solvents with strong hydrogen bond acceptor ability. The high quantum yield of fluorescence in DMSO, DMF, and alcohols qualifies coumarin 4 as a laser dye in the given medium, with kF higher than k(nr). Contrary to previous reports that many H-aggregates are nonfluorescent in nature, coumarin 3 forms highly fluorescent H-aggregates in MeOH and EtOH. On the basis of the restrictions of the Kasha-exciton theory model, we assume that the formation of fluorescent H-dimer aggregates of 3 is driven by π(+)-π(-) interactions. To the best of our knowledge, this is the first report on aggregation of coumarin dye in alcoholic solutions. In addition, restrictions in the fitting procedure relating to determination of the solvation number, n, using the Covington-Newman model of preferential solvation and also the solvent nonideality parameter, h', are discussed in this article.

Matlab Toolbox for RF Receiver Modeling

In this paper a novel RF receiver modeling approach is presented. The novelty consists in the usage of the object oriented programming instead of the usual imperative programming. Classes were defined for entities as signal, non-ideality and RF/analog block, in order to achieve a basic RF receiver model. The main circuit non-idealities were identified, non-ideality parameters and their analytical models were encapsulated into classes. The effectiveness of the proposed modeling approach was demonstrated by developing in MATLAB a fairly complete model of a direct conversion receiver.

Calibration and high fidelity measurement of a quantum photonic chip

Integrated quantum photonic circuits are becoming increasingly complex. Accurate calibration of device parameters and detailed characterization of the prepared quantum states are critically important for future progress. Here we report on an effective experimental calibration method based on Bayesian updating and Markov chain Monte Carlo integration. We use this calibration technique to characterize a two qubit chip and extract the reflectivities of its directional couplers. An average quantum state tomography fidelity of 93.79 ± 1.05% against the four Bell states is achieved. Furthermore, comparing the measured density matrices against a model using the non-ideal device parameters derived from the calibration we achieve an average fidelity of 97.57 ± 0.96%. This pinpoints non-ideality of chip parameters as a major factor in the decrease of Bell state fidelity. We also perform quantum state tomography for Bell states while continuously varying photon distinguishability and find excellent agreement with theory.

TH-A-103-09: Bowtie Filter Designs for Dedicated Breast CT

Purpose: To design bowtie filters with improved properties for cone-beam breast CT in order to improve image quality and reduce dose to the patient. Methods: In breast CT, the relatively uniform composition and approximate rotational symmetry of the object being imaged invite the application of analytic methods to the bowtie filter design problem. It is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Other effects for which compensation can be achieved include spectral change only, or spectral change and variation of overall intensity. The designs that compensate for spectral change or spectral change/intensity require additional software corrections to the calibration scan while the beam hardening design does not. Results: Examples of designs that satisfy the criteria described above are presented. Verification of the performance of the design that eliminates the beam-hardening effect was done by reconstructing simulated projection data. Reconstruction of an experimental data set using a bowtie filter that compensates for spectral change showed a marked reduction in the ring artifact. The performance of the designs depends only very weakly on incident spectrum and tissue composition. By varying the material used in the fabrication of the filter, it is possible to minimize the dynamic range requirement on the detector by dividing it between the calibration scan and patient scan. The designs were based on a cylindrical phantom. Extension of the method to a more realistic shape is straightforward. Conclusion: The special properties of breast CT permit the use of rational design methods. Simulation and preliminary experimental results for our test geometries are encouraging. The next steps are further experimentation and analysis of performance with non-ideal design parameters.

Shock dynamics of weak imploding cylindrical and spherical shock waves with non-ideal gas effects

The author (Anand 2012 Astrophys. Space Sci.342 377–88) recently obtained jump relations across a shock front in non-ideal gas flow taking into consideration the equation of state for a non-ideal gas as given by Landau and Lifshitz. In this paper an analytical solution for one-dimensional adiabatic flow behind weak converging shock waves propagating in a non-ideal gas is obtained by using Whitham's (1974 Linear and Nonlinear Waves (New York: Wiley)) geometrical shock dynamics approach. The effects of an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and (iii) the adiabatic index of the gas, on the shock velocity, pressure, density, particle velocity, adiabatic compressibility and the change in entropy across the shock front, are analyzed. The results provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the imploding shock front.

Shock dynamics of strong imploding cylindrical and spherical shock waves with non-ideal gas effects

In this paper, the generalized analytical solution for one dimensional adiabatic flow behind the strong imploding shock waves propagating in a non-ideal gas is obtained by using Whitham’s geometrical shock dynamics theory. Landau and Lifshitz’s equation of state for non-ideal gas and Anand’s generalized shock jump relations are taken into consideration to explore the effects due to an increase in (i) the propagation distance from the centre of convergence, (ii) the non-idealness parameter and, (iii) the adiabatic index, on the shock velocity, pressure, density, particle velocity, sound speed, adiabatic compressibility and the change in entropy across the shock front. The findings provided a clear picture of whether and how the non-idealness parameter and the adiabatic index affect the flow field behind the strong imploding shock front.