Integral equations for the radial distribution functions of binary mixtures. Equation of state for a binary mixture

A system of integral equations obtained earlier for the radial distribution functions is used for the investigation of the equation of state of binary mixtures in the gaseous, critical, and intermediate regions in the direction isomorphic to the single-component liquid. The question of the universality of critical phenomena in mixtures is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 92–96, January, 1986.     

Microscopic theory of nuclear reactions based on the wave-packet technique

A new approach to describe the dynamics of nuclear reactions is proposed. The approach is based on the discretization of the total Hamiltonian continuum. The usage of the special stationary wave-packet basis makes it possible to reduce the scattering integral equations to matrix ones. The energy singularities of the initial equation kernels are smoothed by the averaging over discretization intervals. The approach is highly universal and allows one to properly take into account various exchange processes. In addition, the wave-packet technique makes it possible to construct effective optical potentials of interaction between composite nuclei.     

Induced twisted-grain-boundary phases in the binary mixtures of a cholesteric and a nematic compound

Thermodynamical, optical-texture and dielectric studies have been performed to study the phase diagram of the binary system of 5-cholesten-3β-ol-octanoate and 4-n-nonyloxybenzoic acid. It is observed that low concentrations of 5-cholesten-3β-ol-octanoate (2–30?mol?%) in 4-n-nonyloxybenzoic acid induce a mean-field phase diagram derived by Renn within the framework of the chiral Chen–Lubenski model. Various optical textures of the twisted-grain-boundary (TGB) phases under different conditions of molecular anchoring have been observed. Weak transitions related to the TGB phases have been detected by temperature dependent dielectric spectroscopy.     

Theoretical and experimental comparison of the Soret coefficient for water-methanol and water-ethanol binary mixtures

The role played by the history of packing in the behaviour of a granular material confined in a column is studied experimentally. The mean pressure applied by the granular assembly to the base is measured as a function of the height of material poured in the column. We obtain reproducible mean vertical normal stress measurements without using a particular procedure to mobilise the wall friction. We focus on the influence of the filling method on the mean vertical normal stress. Filling the column via the edges induces a higher apparent mass of grain than filling it via the centre. Particular attention is devoted to the measurement of the effect of the force sensor stiffness. We show that the lower the base stiffness, the lower the mean pressure on the base. We also vary the packing fraction. We obtain an increasing relation between the apparent mass and the mean packing fraction, and show that this relation depends on the filling method.Received: 4 April 2004, Published online: 20 July 2004PACS: 45.70.Cc Static sandpiles; granular compaction - 81.05.Rm Porous materials; granular materials - 83.80.Fg Granular solidsM. Tixier: Mireille.Tixier@meca.uvsq.fr     

An image encryption algorithm based on spatiotemporal chaos and middle order traversal of a binary tree

This paper proposes an image encryption algorithm based on spatiotemporal chaos and middle order traversal of a binary tree. Firstly, other programming software is used to perform the middle order traversal, and the plaintext image is sorted according to the middle order traversal sequence on the permutation. Secondly, the chaotic sequence is generated using the coupled map lattice to set the chaotic interference value. Finally, the XOR operation between the adjacent pixel values of the replacement image is completed to generate the ciphertext matrix. The simulation and experimental results show that the proposed algorithm can resist typical attacks and has good robustness.     

An enhanced method for generation of binary Fresnel hologram based on adaptive and uniform grid-cross down-sampling

It has been revealed in past research that by uniformly down-sampling the object image prior to the numerical generation, and subsequent binarization of its digital Fresnel hologram, the reconstructed image can preserve the shaded content with favorable visual quality. However, the down-sampling process also severs the lines and blurs the edge patterns that are important in representing the detail information of an image scene. In this paper, we propose a method to overcome this dilemma with an integration of a fast adaptive down-sampling and the uniform down-sampling process. Experimental evaluation has demonstrated that our method is capable of preserving lines and edges, as well as the shaded regions, resulting in superior visual quality of the reconstructed image as compared with the existing approach. In addition, the computation time on the integrated down-sampling method is less than 200 ms on a typical personal computer.     

Precise determination of the Soret,thermal diffusion and mass diffusion coefficients of binary mixtures of dodecane,isobutylbenzene and 1,2,3,4-tetrahydronaphthalene by a holographic grating technique

Within the framework of an international benchmark test, the Soret coefficient S T , thermal diffusion coefficient D T and mutual mass diffusion coefficient D of the three binary mixtures of dodecane, isobutylbenzene and 1,2,3,4-tetrahydronaphthalene with a concentration of 50 wt% of each component at a temperature of 25C have been measured with a holographic grating technique. For the analysis of the experimental data a new numerical correction algorithm based on linear response theory has been employed. The corrections applied are on the order of 1% for S T and 5% for D . The coefficients S T , D and D T are determined with relative errors of a few per cent.     

An all optical approach for developing a system involving Kerr material based switches for cryptographic encoding of binary data depending on the input parity

Optics is a highly potential candidate in super fast data computation and communication because of its strong inherent parallelism. Several all optical logic, arithmetic and data processing systems have been proposed in the last few decades. Many all optical digital encoders and decoders are also reported. In this paper we propose a new and alternative concept of using optics for encrypting a binary number to a suitable binary code to achieve a secured optical communication. This binary number can bear the supporting alphabets and numerals in communication of data. In this process an encrypted data is checked by necessary parity bit to ensure a secure communication. The result is verified using proper simulation.     

Predictions for inclusive reactions based on a parton structure of hadrons

It is proposed that the asymptotic single-particle distributions f(x)=x(dσ/dx) in inclusive reactions should reflect the limiting longitudinal momentum distribution, ∼νW₂(x), of the hypothetical partons constituting a hadron. It is further argued that f(x) becomes, proportional to νW₂(x) as x → 1. Predictions are then made for a large class of inclusive reactions based on our knowledge of νW₂(x) from electroproduction data. For some of these (such as pp → π^±X), in which the predictions differ markedly from the Regge ones, present experiments distinctly favor ours.     

Correlation studies on dielectric and thermodynamic parameters in the binary mixtures of N-methyl aniline and alcohols

The dielectric and thermodynamic studies on polar binary mixtures of N- methyl aniline with alcohols — propan-1-ol and propan-2-ol have been carried out, at different temperatures and mole fractions. LF impedance analyzer, Microwave bench and Abbe’s refractometer are used respectively in radio, microwave (X-Band) and high frequency regions to determine the dielectric data. The experimental data is used to correlate the dielectric and thermodynamic parameters — static permittivity, high frequency permittivity, Kirkwood effective correlation factor, corrective Kirkwood correlation factor, excess permittivity, excess Helmholtz free energy, dipole moment, excessive dipole moment, relaxation time, excess inverse relaxation time and the excess thermodynamic parameters. These parameters are used to interpret the molecular interactions between the molecular species of the liquid mixtures.     

Benchmark values for the Soret,thermal diffusion and diffusion coefficients of three binary organic liquid mixtures

With the aim of providing reliable benchmark values, we have measured the Soret, diffusion and thermal diffusion coefficients of the three binary mixtures of dodecane, isobutylbenzene and 1,2,3,4 tetrahydronaphthalene for a concentration of 50 wt% at a temperature of 25C. The experimental techniques applied by the five participating laboratories are transient holographic gratings, annular and parallelepipedic thermogravitational columns, and vertical parallelepipedic columns with velocity amplitude determination by laser doppler velocimetry. The systems have also been studied in a annular thermogravitational column filled with a porous medium in the gap. There is a good agreement between the different experiments with deviations of the order of a few per cent in most cases (8.5% at most). The numerical values are tabulated in the paper.     

Luminance adaptation model for increasing the dynamic range of an imaging system based on a CCD camera

We propose a luminance adaptation model (LAM) to increase the dynamic range of an imaging system when scenes containing areas of low and high illumination are imaged. The LAM that we developed is based on capturing images at different exposure times to obtain digital levels within the linear response zone for all the pixels in the image. The levels are subsequently transformed to a reference exposure time that is common to all pixels. We use a linear transformation whose coefficients are determined by the digital levels obtained for a set of flat-spectrum samples. In this study, the LAM is applied to a multispectral imaging system that is based on a CCD camera used for color measurements and spectral reconstructions. It is shown to be a very useful method for increasing the dynamic range of the system, whilst maintaining its accuracy.     

Evaluation of a noise reduction system for the assessment of click-evoked otoacoustic emissions

A recently proposed noise reduction system intended to facilitate the assessment of click-evoked otoacoustic emission (CEOAE) in noisy environments [Comput. Biol. Med. 30, 341 (2000)] is evaluated using 13 normally hearing ears and 9 ears with a sensorineural hearing loss. The noise reduction system is based on an adaptive noise canceller design using an additional noise-only reference microphone and intended to reduce externally generated noise. The system is tested in quiet and at different levels of white noise. The three main design parameters of the noise reduction system (adaptation time constant, length of the adaptive filter, and position of the noise reference microphone) are varied systematically in different experiments. With the noise reduction system active, CEOAE can be assessed correctly at noise levels which are 5 to 9 dB higher than without the noise reduction system. For the range of adaptation time constants considered (65.6 to 656 ms), no statistically significant effect on the amount of noise reduction is observed. Noise reduction is highest when the reference microphone is positioned close to the ear probe. Using this reference microphone position and adaptive filters of 6.56 ms in length, average noise reductions of 7.17 to 8.50 dB are achieved.     

Simulation of phase equilibria and interfacial properties of binary mixtures on the liquid-vapour interface using lattice sums

Molecular dynamics simulations of Lennard-Jones binary mixtures were performed to obtain phase equilibria and thermodynamic properties for the liquid—vapour interface. The dispersion interactions were handled using the lattice sum method where the full interaction is obtained and there is no requirement for any long range correction to the properties. The application of the method using the Lorentz—Berthelot combining rule for unlike interactions is discussed. The coexisting densities, adsorption of molecules at the interface and surface tension are the main results of this work. Coexisting properties were compared with Gibbs ensemble Monte Carlo results and with those of the grand canonical Monte Carlo method combined with the histogram reweighting technique, and good agreement was found. The lattice sum method results were compared with those of the spherically truncated and shifted potential to analyse the truncation effect. The adsorption of molecules at the interface and surface tension increase with interaction.     

Design and evaluation of surrogate mixtures for diesel based on the isolated droplet configuration

The development of simplified surrogate mixtures able to replicate combustion-related behaviors of chemically complex fuels is essential for their simulation with computational tools, a key step towards the design of high-efficiency and low-emission combustion applications. This work proposes to use the isolated droplet configuration as a benchmark to formulate and validate surrogates that capture the vaporization and soot production characteristics of a first-fill diesel and a diesel-biodiesel mixture. To that end, droplet vaporization experiments and a multicomponent model were coupled to produce blends matching the evaporation behavior, whereas the soot tendency was incorporated through tests at the ASTM D1322 smoke point lamp and the Oxygen Extended Sooting Index (OESI). The so-obtained surrogate blends were subsequently validated for both characteristics. Their evaporation curves proved to match remarkably well those obtained for the target fuels, with noticeable improvements when increasing the number of compounds in the mixture. As for the sooting behavior, the proposed blends achieved a good emulation in terms of the design parameter (OESI), confirming the validity of the proposed methodology. On the other hand, an additional and independent validation of the sooting propensity through the quantification of the mass of soot produced by isolated droplets under a high-temperature and reducing atmosphere revealed significantly higher soot yields for the surrogates when compared to the target fuels. These results highlight the relevance of the configuration used when designing and validating surrogates, since the same blends can provide substantial differences when evaluated through different sooting indices.     

水声无源材料回声降低测量时反聚焦方法

提出了利用时间反转(时反)聚焦技术的水声无源材料回声降低测量方法。首先实现有界水声环境下有、无试样接收信号的时反聚焦,然后利用聚焦信号测量试样反射系数,最后通过标准试样对反射系数进行修正,从而得到试样的回声降低测量值。在小型水池中进行了铝板试样和钢板试样回声降低的测量,铝板试样的尺寸为1.1 m×1.0 m×0.005 m,测量频率范围为3~20kHz,钢板试样尺寸与铝板试样相同,测量频率范围为0.5~20 kHz,测量结果经修正后与平面波理论计算值基本一致,和理论计算值的相对误差小于10%,扩展不确定度小于1.5 dB。本方法采用时反原理实现了接收信号的空时聚焦,提高了测量信混比,因此适用于非自由场环境下无源材料回声降低的测量试验,尤其适用于低频的回声降低测量。     

水声无源材料回声降低测量时反聚焦方法

提出了利用时间反转(时反)聚焦技术的水声无源材料回声降低测量方法。首先实现有界水声环境下有、无试样接收信号的时反聚焦,然后利用聚焦信号测量试样反射系数,最后通过标准试样对反射系数进行修正,从而得到试样的回声降低测量值。在小型水池中进行了铝板试样和钢板试样回声降低的测量,铝板试样的尺寸为1.1m×1.0×0.005m,测量频率范围为3~20kHz,钢板试样尺寸与铝板试样相同,测量频率范围为0.5~20kHz,测量结果经修正后与平面波理论计算值基本一致,和理论计算值的相对误差小于10%,扩展不确定度小于1.5dB。本方法采用时反原理实现了接收信号的空时聚焦,提高了测量信混比,因此适用于非自由场环境下无源材料回声降低的测量试验,尤其适用于低频的回声降低测量。