Digital Computer Calculations Research Articles

Fractal dimension of the morphology on differently oriented surfaces of coal preparations

Choosing the surface of a lump section was justified to determine the degree of metamorphism by the index of gray shade intensity. The main method is optical spectroscopy using a video-optical complex MBI-11, NB 200 with subsequent digital computer processing and calculation of the fractal dimension (Scope photo software) of microphoto images of coal matter preparations by lump sections. The values for the index of gray shade intensity of photographic images of surfaces (section, bedding, cut) for lump sections based on samples of coals of various grades were analyzed. It has been established that the average values of the degree of metamorphism indices for different surfaces of the preparation differ, which is confirmed by low correlation coefficients: 0.585 (section-bedding), 0.666 (section-cut), 0.462 (cut-bedding). It has been found that the fractal dimension, which characterizes the complexity of the morphology of the surfaces under study, reflects an increase in the amount and orderliness of hydrocarbons associated with a change in the degree of metamorphism. It was proven that its most natural decrease related to an increase in the degree of metamorphism, is observed on surfaces perpendicular to the bedding (section).

Image-based occupancy positioning system using pose-estimation model for demand-oriented ventilation

Dynamic changes in the position, number, and activities of occupants create various indoor scenarios that affect the operation of and energy required for heating, ventilation, and air conditioning (HVAC) systems. HVAC systems can use less energy by adapting their operational parameters according to the occupant distribution. However, accurate and non-intrusive occupancy positioning systems have yet to be established for conventional HVAC and more recently developed demand-oriented ventilation (DOV) systems. Herein, a novel image-based occupancy positioning system is proposed. This system uses multiple cameras to capture images from different views and a computer to perform digital image processing and three-dimensional (3D) reconstruction. Data fusion and 3D reconstruction algorithms were developed based on skeleton key points extracted from the images with a human pose estimation model. The entire system was built and tested in a multi-function room under two different scenarios. The results showed that the system provides positioning and orientation information for a dozen of people in real time. Because the system requires an ordinary computer and conventional surveillance cameras, it can be integrated into existing video surveillance systems to avoid privacy issues. As the speed of digital image processing and computer calculations increases, the cost of the system will decrease; these characteristics provide a solid foundation for the operation of highly efficient DOV systems.

Industrial Insurance Groups Cost Management. Mathematical Modeling and Applied Software

This paper covers acquisition cost control optimization in the insurance sector through managerial tools that include optimization models applied method, and analysis within the insurance companies to achieve higher efficiency. The model development with presented costs volume and supposed market volume in each product branch is needed to optimize acquisition costs in insurance companies. The model has been simplified due to the presence of big data in each product branch. Our study is based on classic works and textbooks on optimization and non-linear programming. The results of digital computer calculations for two types of insurance activity are present here. The applied software tool for the acquisition costs allocation is also considered.

The lowest excited states of BH

Digital computer calculations in SCF MO approximation on the two lowest excited states of BH, 1σ22σ23σ4σ, 3Σ+ and 1Σ+, from 2.0 a.u. out to dissociation are reported. As shown previously by Grimaldi and coworkers [1], these are stable Rydberg states, but it is now shown that the 3Σ+ potential curve on increasing the interatomic distance R goes over a maximum and then becomes a repulsion curve dissociating to normal atoms. The changing characteristics of the 2σ, 3σ and 4σ orbitals as a function of R are described and discussed.

Modeling of Silicon Vapor Phase Epitaxy Using Stefan-Maxwell Formalism

The vapor-phase homoepitaxy of monocrystalline silicon by reduction of chlorosilanes is modeled using a novel approach. With digital computer calculation, the growth rate of silicon is predicted under ambient pressure (1.0 atm or 101.325 kPa) in the high-temperature regime 1200—1600 K, where silicon growth is expected to be mass-transport limited. This study considers four different initial stoichiometries, namely, 0.1% SiH4 + 0.4% HCl + H2, 0.1% SiCl4 + H2, 0.5% SiCl4 + H2, and 0.2% SiHCl3 + H2 in the Si-Cl-H system in order to make comparisons between the predicted and the experimentally determined growth rates. By combining the iterative equilibrium constant method with the Stefan-Maxwell relations for diffusion in a multi-component gas-phase, the respective molar fluxes of nine gaseous species that include SiCl4, SiHCl3, SiH2Cl2, SiH3Cl, SiH4, SiCl2, SiCl, SiCl3, and Si(g) were computed for steady-state condition; and the data on fluxes enabled the determination of the net silicon flux to the surface of the substrate. The computed rates were compared to the measured deposition rates of silicon.

Simplified ionospheric regional model for telecommunication applications

A simplified model of the key ionospheric characteristics of vertical incidence such as fo F2 M(3000)F2, h′F, foF1, and f0E that are used for prediction of operational parameters of HF telecommunication systems in a restricted area has been developed. The simplified ionospheric regional model (SIRM), is based upon the Fourier analysis of the monthly median values of these characteristics from seven ionospheric stations in Europe. It is shown that only 12 dominant Fourier coefficients, expressed as a function of local time (LT), solar activity and geographic latitude are sufficient to reproduce the main features of the diurnal, seasonal, and solar cycle behavior of the mid‐latitude ionosphere under median conditions. The model is in a very suitable form for digital computer calculation of the characteristics for a given position, instant of time, and solar activity.

Acoustic waves in solids with random cavities, I: Effective macroscopic parameters

The propagation of acoustic displacement disturbances in an isotropic porous solid is studied experimentally and theoretically under the assumption that the solid contains a large number of cavities being dispersed randomly with respect to their positions, sizes and shapes. The influence of the cavities on the effective velocities of the propagation of acoustic plane waves is considered in the spherical and ellipsoidal cavities approximation. The validity of the spherical cavities approximation is confirmed experimentally and by digital computer calculations for low frequecies and dilute concentrations of the cavities.

Simulating chaotic behavior with finite-state machines.

The iterates of the logistic map, ${x}_{n+1}$=${\mathrm{rx}}_{n}$(1-${x}_{n}$), exhibit chaotic behavior for many values of r\ensuremath{\in}[3.57,4.0]. However, if we treat x as an m-state discrete variable, as is done in any digital computer calculation, then the iterates of x invariably form short limit cycles of length \ensuremath{\approxeq} \ensuremath{\surd}m for chaotic values of r. Although this result questions the validity of digital computer simulations of chaos, we nevertheless find that the statistical properties of the continuous equation, such as the invariant probability distribution and the Lyapunov exponent, are preserved in these cycles. We also find that the transition between periodic and chaotic behavior is still well defined in the discretized map.

Reduced Temperature Return-to-Power Demonstration

A demonstration of reduced temperature return-to-power was performed at the 920-gross-MW(electric) Tihange nuclear station in Belgium. A rapid power escalation of 320-MW(electric) in gross output was achieved using control rod withdrawal and moderator temperature reduction. Of that total, 230 MW(electric) was achieved on a core reactivity increase provided by a 9 K (16/sup 0/F) drop in moderator temperature. Digital computer calculations and analog simulations accurately predicted both core and systems response.

Ion-beam-induced topography and surface diffusion

The development of surface microtexture along with ion-impact-enhanced surface and bulk diffusion processes is important for users of ion beams and plasmas for thin film or material processing. Even in those applications where texturing is not desired, an understanding of the process of texturing will permit proper corrective action when texturing is found to occur. Surface microtexturing produced using ion-beam sputtering and simultaneous deposition of impurities is described both in terms of a simple diffusion model and with regard to detailed studies of the initiation, development, and failure of individual sputter cones. Digital computer calculations are presented which follow surface feature development under sputtering. These calculations appear to confirm the role of ion reflection in the development of cones. A coating associated with the impurity deposition is often observed on individual cones. This coating appears to play a role both in the initial development of cones and in the subsequent evolution of second generation cones in a steady-state process. Surface diffusion, in excess of that expected from thermally activated diffusion alone, has been observed as the ion-beam current density is increased. This impact-enhanced diffusion appears to depend on cooperative effects between multiple ion impacts.

Digital Computer Algobithms for the Calculation of Generating Capacity Reliability Indices

This paper presents a complete and consistent set of equations suitable for digital computer calculation of generating capacity reliability indices. Each set of equations is accompanied by a brief and relatively simple numerical example to illustrate the proposed procedure. The algorithms detailed commence with the equations for building capacity models required in the Loss of Load Expectation technique using two state and multi-state generating unit representations. These algorithms are then extended to the equations required in the Frequency and Duration method.

Computer-aided reconstruction of the image contrast of atom clusters from diffractograms of electron micrographs

By developing Lommel's Bessel integration with respect to the Gaussian scattering angular distribution, the Kirchhoff diffraction integrals indicating image profiles of atom clusters in high resolution electron microscopy, when taking account of the complex scattering amplitude and optical phase of the objective lens aberrations, can be performed as functions of the generalized spatial frequency, image distance and defocusing. The light optical diffractograms obtained by the Fourier-Bessel transformation; which involves the coherent wave consisting of both phase and amplitude contrast transfer functions, as well as the incoherent wave consisting of square terms; provide a useful method of measuring the aberration coefficients, scattering factor phase and the exact amount of defocus. It follows that the image contrast of clusters can be reconstructed from the diffractograms by evaluating the spatial frequencies and scattering factor phases of individual clusters with the aid of digital computer calculations in place of the previous Monte-Carlo method.

Representation of MAagnetic Saturation in the Synchronous Machine Model in an Electro-Mlagnetic Transients Program

The Electromagnetic Transients Program (EMTP) has offered for the last two years a representation Qf synchronous machine dynamics [1-3]. That representation is, however, limited to linear machines only, i.e., the nonlinear effects of magnetic saturation are neglected. This paper describes an extension to the existing modelling capability permitting the introduction of magnetic saturation effects. The theory and implementation of this extension are discussed and sample digital computer calculations are presented.

Surge arresters for sheath protection in crossbonded cable system

The paper presents results of digital computer calculations of the sheath overvoltages and the energies absorbed by sheath-protecting surge arresters in a crossbonded cable system. Especially, the energy loading of the arresters during energisation and discharge of an underground cable-overhead line configuration is considered. An analysis of the natural wave propagation characteristics of the cable system is given. Based upon this analysis a frequency-independent wave propagation of all modes has been adopted as a basis of the calculation method. The requirements concerning the choice of the arrester are discussed.

Direct fast Fourier transform of bivariate functions

A mathematical development is presented for a direct computation of a two-dimensional fast Fourier transform (FFT). A generalized mathematical theory of holor algebra is used to manipulate coefficient arrays needed to generate computational equations. The result is a set of equations which involve elements from throughout the two-dimensional array rather than operating on individual rows and columns. Preliminary digital computer calculations verify the accuracy of the technique and demonstrate a modest saving of computation time as well.

Dynamic characteristics of rotor blades

The transmission matrix method is used to determine the dynamic characteristics (natural frequencies and the associated mode shapes) of rotor blades. The problems treated are combined flapwise bending, chordwise bending, and torsion of twisted non-uniform blades and its special subcases. The orthogonality relations that exist between the natural modes are derived. The method is appealing because of its simplicity for programming for digital computer calculations and also the inputs are generated very easily since they are merely the coefficients of the differential equations of motion.

The acoustic response in a liquid layer overlying a multi-layered viscoelastic half-space

A Green function is constructed that represents the steady-state acoustic response in a liquid layer overlying a Voigt viscoelastic multi-layered half-space. The effect of the solid half-space is characterized by a ratio related to the impedance of the sub-bottom. This ratio is evaluated by first developing a matrix recurrence relation for the potentials in the solid which, when repeatedly applied, directly relates the first viscoelastic layer's response to the last layer's. After boundary conditions are applied at the liquid-solid interface, the impedance ratio is obtained from another matrix relation. The result is in a form convenient for digital computer calculations. The response for the homogeneous single layer or half-space is shown to be consistent with existing results.

Monte Carlo simulation of the X‐ray fluorescence excited by discrete energy photons in homogeneous samples including tertiary inter‐element effects

AbstractA Monte Carlo model is derived for the simulation X‐ray fluorescence from homogeneous samples including primary, secondary and tertiary fluorescence events. The model is designed specifically for an annular radioisotope source mounted coaxially with a circular detector. It is verified with analytical relationships for the limited case of fixed sample entrance and exit angles. The results indicate accuracies (2% or better) that are well within our knowledge of X‐ray fluorescence parameters (such as fluorescence yields), yet can be calculated with very modest (15 seconds) digital computer calculation time.

Hydrodynamics of Large Objects in the Sea Part II: Motion of Free-Floating Bodies

A numerical scheme was developed in Part I utilizing digital computer calculations to determine wave excitation forces as well as added mass and damping coefficients for large objects in the sea. The analysis was carried out within the framework of linear theory for bodies of arbitrary shape, either submerged or semisubmerged, in water of finite depth. In this Part II, an analysis is presented for the motion of large free-floating bodies. The results obtained by methods of Part I are utilized in conjunction with the equations of motion of the floating body to determine the response induced by wave excitation. Numerical results are presented for the response of a sphere and a short, vertical, circular cylinder floating in water of finite depth.

Digital computer calculation of human pulmonary mechanics using a least squares fit technique

We have calculated pulmonary mechanics on six human subjects using a digital computer to least squares fit the equation describing pulmonary mechanics: P= 1 C V+RV for the constants C and R, during both the inspiratory and expiratory cycles. Values for compliance and resistance were found to be statistically identical with those calculated by methods which use isolated points in the breathing cycle. No difference in mechanics was observed between inspiration and expiration. The method's advantages over isolated-points methods are that best-fit parameters are better representations; it calculates parameters independently for inspiration and expiration; and it functions in real time.