Classical Calculation Methods Research Articles

Quantification of synergistic, additive and antagonistic effects of aerosol components on total oxidative potential

The interaction-based oxidative potential (OPint) represents the prediction of binary mixture effects distinguishing from linear additivity by including information on binary mixtures among PM components. The objective of this work is to develope a reliable estimate on the possible synergistic or antagonistic possibility of binary PM components and to quantify the combined effect. We firstly assessed the interactions among PM components in generating the OP based on DTT consumption rate and AA depletion. We started with the standard solution sequence (from 0.005 to 10 μM), including quinones (PQ, 1,2-NQ, and 1,4-NQ) and metals (Cu, Mn, and Fe). The interactions between metals were antagonistic interactions in DTT consumption. Cu showed antagonistic interaction with PQ, but additive with 1,2-NQ and 1,4-NQ. Mn interacted synergistically with 1,4-NQ in DTT consumption but antagonistically with PQ (where CPQ < 2.5 μM) and 1,4-NQ (where CPQ < 2 μM). Fe showed synergistic with quinones in investigated concentration range (from 0.01 to 5 μM). Finally, applying a moderate approach, on the basis of interaction magnitude (M = 5), resulted in 1–17% higher environmental risks, compared with the classical calculation method using simple addition. This work highlights a new approach to quantify the interaction effects between metals and quinones in PM components, and apportioning the components’ contributions for PM OP.

An Extension of Taylor’s φ‐Circle Method and Some Stability Charts for Submerged Slopes

Taylor’s φ‐circle method is a classical method for slope stability calculation, which has analytical solutions. Taylor derived equations in two cases separately, namely, (i) the outlet of the critical failure surface is at the slope toe and (ii) the outlet of the failure surfaces is not at the slope toe. The method is only appropriate for two conditions (without underground water table in slopes or totally submerged slopes). In this study, a general equation that unifies the equations of the two cases is proposed and partially submerged condition is introduced. The critical failure surfaces corresponding to the minimum factor of safety are determined using the computer program proposed by the authors. The general expression of the safety factor of slopes under the following four conditions is derived, namely, (i) partly submerged, (ii) completely submerged, (iii) water sudden drawdown, and (iv) water slow drawdown. The corresponding charts for practical use are available.

Comparison of FDTD and TDWP Methods for Simulating Electromagnetic Wave Propagation above Terrains

Abstract — Researchers have always been in favor of path loss calculation in different media for applications such as telecommunication link design. Wave propagation calculations in large spaces using the FDTD method is time-consuming and imposes a great computational burden. For this reason, to replace the classical FDTD method for wave propagation simulation and path loss calculation in large spaces, optimized methods, namely TDWP, have been provided. In this paper, the use of the TDWP method for wave propagation simulation and path loss calculation above a terrain is investigated. Longitudinal components of ground-waves are taken into account (including direct waves, ground reflections, and surface waves). Propagation space is longitudinally divided into smaller FDTD windows with finite length. The electromagnetic pulse travels through these windows from left to right to the desired point. But despite its capability in reducing computational burden and increasing processing speed, TDWP has lower precision in instantaneous field simulation and calculation of propagation coefficients, so that results obtained from FDTD and TDWP are clearly different. In this paper, some efficient methods are proposed, which yield an increase in method accuracy.

The study on the measurement accuracy of non-steady state temperature field under different emissivity using infrared thermal image

In this paper, the temperature measurement accuracy of infrared thermal image under different emissivity is studied. Firstly, according to the formula of infrared temperature measurement, the influence of the object surface emissivity on the measurement accuracy of infrared thermal image is analyzed. The factors affecting the emissivity of the object are found. Secondly, the limitation of classical emissivity calculation method in infrared temperature measurement is explained. Thirdly, a model for improving the temperature accuracy of the non-steady state temperature field based on the emissivity of the infrared image is obtained, and the theoretical formula is obtained. Finally, three experiments of cast iron and stainless steel are carried out. The correctness and feasibility of this method is verified by the experimental results.

Software complexes and new approaches to non-linear analysis of framed structures

There is a great number of non-linear tasks which can be solved with the use of computer-based simulation and finite elements method (FEM). But in order to ensure high speed and accuracy of calculations it is necessary to use new mathematical models and algorithms. The analysis of the known FEM forms and approaches to numerical solution of tasks based on force method is performed in this work. Represented in the document is formulation of the finite-element stress method and algorithmization of the classical force method for calculation of framed structures based on the equation of strain compatibility – contour forces method. Statement of problems which can be more effective from the point of view of elastic-plastic deformations at numerical solution is considered. In particular, the hybrid finite-element method based on the generalized Mohr formula for determination of long bar stiffness coefficient with account of non-linear behavior. The main relationships for creation of finite-element method equation system in the form of force method are represented.

Serial, Anthropomorphic, Spatial, Mechatronic Systems Can Be Studied More Simply in a Plan

The mobile, mechatronic, robotic, serial, spatial, anthropomorphic type systems, which are currently the most used in the machine building industry, can be studied much more simply in a plan instead of the usual spatial study. This not only simplifies the understanding of these systems (including from a didactic point of view) but also facilitates computational methods, moving from matrix analytical methods to more simple classical methods. Usage is done by conversion, so nothing is lost from the essence of physic-mathematical phenomena. The idea of moving from spatial to planar study has been centered over time on all major mechanisms when it was possible, precisely for ease of calculation and working methods, but also for a better understanding of physical phenomena. The vast majority of classical mechanisms can be treated as they move in most cases into a master plan. This is the case with known mechanical transmissions, classic motors of all types, working mechanisms, engine or lucrative cars, etc. In anthropomorphic robots, the method is no longer used because they work clearly in a well-defined space. We used the idea to divide this space into a main work plan that can rotate around a main axis so that the study of all movements is done in the workplan and then the rotations of these parameters corresponding to the rotation of the work plane around the main axis of rotation. The physical-mathematical methods are greatly simplified in this way, from matrix difficult calculations to simple, classical analytical calculation methods.

Non-dipolarity of channeling radiation at GeV beam energies

At electron-beam energies higher than about 1GeV, the dipole approximation for channeling radiation (CR) loses its validity. The reason of non-dipolarity consists in the coupling of the longitudinal and transverse motions of the channeled particle, while, at lower energies, its transverse motion is assumed to be independent from the longitudinal one and is governed by the continuous potential only. The non-dipolarity of CR appears in a change of its energy spectrum and intensity. This effect cannot be ignored, e.g., at simulation of positron production by means of pair creation in the non-conventional scheme of a hybrid positron source. We present a classical method for calculation of the CR spectrum in the non-dipole case.

Serial, Anthropomorphic, Spatial, Mechatronic Systems can be Studied More Simply in a Plan

The mobile, mechatronic, robotic, serial, spatial, anthropomorphic type systems, which are currently the most used in the machine building industry, can be studied much more simply in a plan instead of the usual spatial study. This not only simplifies the understanding of these systems (including from a didactic point of view) but also facilitates computational methods, moving from matrix analytical methods to more simple classical methods. Usage is done by conversion, so nothing is lost from the essence of physic-mathematical phenomena. The idea of moving from spatial to planar study has been centered over time on all major mechanisms when it was possible, precisely for ease of calculation and working methods, but also for a better understanding of physical phenomena. The vast majority of classical mechanisms can be treated as they move in most cases into a master plan. This is the case with known mechanical transmissions, classic motors of all types, working mechanisms, engine or lucrative cars, etc. In anthropomorphic robots, the method is no longer used because they work clearly in a well-defined space. We used the idea to divide this space into a main work plan that can rotate around a main axis so that the study of all movements is done in the workplan and then the rotations of these parameters corresponding to the rotation of the work plane around the main axis of rotation. The physical-mathematical methods are greatly simplified in this way, from matrix difficult calculations to simple, classical analytical calculation methods.

Expert System of Chili Plant Disease Diagnosis using Forward Chaining Method on Android

This research was conducted to make an expert system that is able to diagnose disease in chili plants based on knowledge that provided directly from the experts. This research uses classical probability calculation method in calculating the percentage of diagnoses and implemented on the Android mobile device. This research consisted of 37 symptoms data, 10 data of chili disease caused by fungi, and 10 rules. This expert system uses forward chaining inference method. Test results shows: (1) Functional testing using the Black Box Equivalence Partitioning (EP) method give the results as expected on the test scenario on each test class. (2) Expert testing by comparing the results of manual and system calculations matches and run well. (3) User acceptance test is done to 53 respondents which is divided into four groups of respondents. The first respondents group that is consisting of experts of chili disease give average score of 85.14% (excellent). The second group that consist of Agriculture Department students give score of 84.13% (excellent). The third respondent group that consist of Computer Science Department students give score of 84.28% (excellent) whereas the last group (chili farmers) give a score of 86% (excellent).

ABOUT TRACK CIRCUIT CALCULATION METHOD DEPENDENT ON FERROMAGNET PROPERTIES IN CONDITIONS OF TRACTION CURRENT NOISE INFLUENCE

Purpose. The work is intended to investigate the electromagnetic processes in impedance bond in order to improve noise immunity of track circuits (TC) for safe railway operation. Methodology. To achieve this purpose the methods of scientific analysis, mathematical modelling, experimental study, a large-scale simulation were used. Findings. The work examined the interference affecting the normal performance of track circuits. To a large extent, part of track circuit damages account for failures in track circuit equipment. Track circuit equipment is connected directly to the track line susceptible to traction current interference, which causes changes in its electrical characteristics and electromagnetic properties. Normal operability, performance of the main operating modes of the track circuit is determined by previous calculation of its performance and compilation of regulatory tables. The classical method for determination of track circuit parameters was analysed. The classical calculation method assumes representation of individual sections of the electrical track circuit using the quadripole network with known coefficients, usually in the A-form. Determining the coefficients of linear element circuit creates no metrological or mathematical difficulties. However, in circuits containing nonlinear ferromagnets (FM), obtaining the coefficients on the entire induction change range in the cores is quite a difficult task because the classical methods of idling (I) and short circuit (SC) are not acceptable. This leads to complicated methods for determining both the module and the arguments of quadripole network coefficients. Instead of the classical method, the work proposed the method for calculating the track circuit dependent on nonlinear properties of ferromagnets. Originality. The article examines a new approach to the calculation of TC taking into account the losses in ferromagnets (FM), without determination of equivalent circuit quadripole network coefficients. When building the FM reversal model in parallel magnetic fields, the most accurate methods are the approximation ones that take into account not only the changes in values and over time, but also their derivatives. The development of computer hardware and software makes real the mathematical methods for calculating TC with significant change in ferromagnetic inductance, including the saturation areas. Herewith, it is important to search for approximating analytical expression that describes the dynamic limit hysteresis loop (HL). Practical value. The changes in the electrical parameters of the same TC were analysed using the classical and the new calculation methods, the difference made less than 10%. The work introduced some measures to increase operational noise immunity of TC.

Application of Fracture Mechanics to Determine the Remaining Lifetime of the Old Steel Bridges Decks

This paper presents a procedure based on fracture mechanics to predict the evolution of cracks detected in a part of steel bridge deck, still in operation, and establishing thus remaining lifetime below a certain range of application from future traffic. It is also described an experimental program conducted on samples from available material, to determine the material factors “C” and “m” involved in Paris formula and their use in a calculation procedure for simulating crack growth detected. Finally is presented a comparison with results obtained from a classical calculation method, the cumulative damage rule of Palmergren-Miner.

Robustness Analysis of an Aircraft Design for Short Takeoff and Landing

As part of the Collaborative Research Center 880, preliminary aircraft design activities are carried out for a new class of low-noise cruise-efficient short takeoff and landing (CESTOL) transport aircraft. A corresponding aircraft is quite different from a state-of-the-art commercial aircraft because of the use of a high-lift system with active flow control. The fact that new technologies are not sufficiently understood yet in combination with the assumption of common design data and the use of classical calculation methods expresses itself in uncertainties that are of epistemic character. The robustness of a deterministic CESTOL aircraft design toward parameters such as the necessary engine thrust, direct operating costs, and the maximum takeoff and landing distances is investigated here concerning the mentioned uncertainties. For this purpose, a stochastic description of parameter variations of the design is formulated. Stochastic quantities are computed by Monte Carlo sampling to rate the robustness. A distributed component-based software implementation is used to perform the Monte Carlo sampling. The software system is installed on a Linux cluster with several multi-CPU computers; a deterministic sample is simulated through the design program PrADO.

A high-performance algorithm for calculating conjunctive and disjunctive terms in polynomial representations of Boolean functions

The computer calculation of values of Boolean functions and systems of Boolean functions represented by normal polynomial forms starts from calculating values of terms of this polynomial followed by operations performed over the results. For the classical calculation method, this process is sequential. In this work, an algorithm is given that uses no more than one logical operation and one comparison to calculate the values of disjunctive and conjunctive terms of polynomial forms.

Calculation of D-Section Classical V-Belt Power Rating in Different Reliability

The deficiencies of the Classical V-belt power rating calculation method in GB / T 11355 and GB / T 13575 is pointed. A new formula modifying the power rating with reliability factor is introduced. The data resulting from the step stress accelerated life testing of D-section Classical V-belt is transformed into equivalent limit stress data which is normal distribution, and then the limit stress of D-section Classical V-belt in different reliability and the corresponding reliability factor are determined, a calculating example by the new method is provided.

A new reduction method for phase equilibrium calculations

Phase equilibrium calculations require the most important computational effort in many process simulators and in reservoir compositional simulations. In this work, a new reduction method for phase equilibrium calculations is proposed. A new set of independent variables (and the related set of error equations) is introduced, based on the observation that, under certain conditions, the equilibrium ratios can be related only to some component properties (elements of the reduction matrix) and to equation of state parameters. The new formulation leads to simpler expressions of the elements of the Jacobian matrix. Some important features are presented, and an interesting and useful link with classical flash calculation methods is revealed. The reliability and efficiency of the proposed method are tested on several synthetic and reservoir hydrocarbon mixtures. The proposed method proves to be robust and it performs in all cases better than previous reduction methods. Finally, it is discussed how the new set of independent variables can be used for a variety of phase equilibrium calculations.

Optimization of Material Properties Using Genetic Algorithms

The genetic algorithm method was used in the present work as an alternative to classical calculation methods. It can be used in the situations where we search an optimal solution and a problem has many variable parameters. In this work the genetic algorithm method was applied in order to decompose the texture function into ideal components and also to optimize elastic constants by an appropriate choice of texture function. These example applications of genetic algorithm method show its potential in the field of material engineering.

Cycles of two-dimensional systems: Computer calculations, proofs, and experiments

One of the central problems in studying small cycles in the neighborhood of equilibrium involves computation of Lyapunov’s quantities. While Lyapunov’s first and second quantities were computed in the general form in the 1940s–1950s, Lyapunov’s third quantity was calculated only for certain special cases. In the present work, we present general formulas for calculation of Lyapunov’s third quantity. Together with the classical Lyapunov method for calculation of Lyapunov’s quantities, which is based on passing to the polar coordinates, we suggest a method developed for the Euclidian coordinates and for the time domain. The calculation of Lyapunov’s quantities by two different analytic methods involving modern software tools for symbolic computing enables us to justify the formulas obtained for Lyapunov’s third quantity. For quadratic systems in which Lyapunov’s first and second quantities vanish, while the third one does not, large cycles were calculated. In the calculations, the quadratic system was reduced to the Liénard equation, which was used to evaluate the domain of parameters corresponding to the existence of four cycles (three “small” cycles and a “large” one). This domain extends the region of parameters obtained by S.L. Shi in 1980 for a quadratic system with four limit cycles.

Buckling strength verification of cantilevered cylindrical shells subjected to transverse load using Eurocode 3

At present, there are only a few studies concerning the application of different types of buckling strength verification according to Eurocode 3 at combined loading. Besides the stress design as classical hand calculation method of checking cylindrical steel shells against buckling failure, the new Eurocode 3 also offers two global numerical analyses at different modelling levels. The linear buckling analysis (LBA) combined with a materially nonlinear but geometrically linear analysis (MNA) is the simpler concept from the perspective of the modelling and calculation effort. The more sophisticated method is a geometrically and materially nonlinear analysis of the imperfect structure (GMNIA). This paper presents the application of both numerical concepts to the cantilevered shell subject to a transverse load at the free edge. The results are compared to those from stress design. There are specific features at both types of numerical analysis: As the determination of the plastic reference resistance and the buckling parameters is the main focus at MNA/LBA, the choice of proper equivalent geometric imperfections demands special diligence at GMNIA. The presented analyses show that the GMNIA concept in connection with consistent equivalent geometric imperfections may lead to a safe and economic design of cylinders subject to combined loading. At the particular load case the MNA/LBA concept currently suffers from the lack of proper regulations concerning the determination of the overall buckling reduction factor.

Adsorption of tetraethylammonium ions on Bi(111) single crystal plane from solutions in ethanol

The adsorption of tetraethylammonium (TEA+) ions on the (1 1 1) plane of the bismuth single crystal from solutions in ethanol has been investigated by impedance measurement method. It was found that the ionic charge due to the specific adsorption of TEA+ ions in ethanol can be obtained using the classical calculation methods for simple ions. The experimental data were obtained in 0.02 M mixed-electrolyte solutions and the calculations performed with electrode potential as the independent electrical variable. The Gibbs energy of adsorption of TEA+ ions has been calculated using the simple virial adsorption isotherm and it was found that the adsorption of TEA+ cations is weaker than the adsorption of halide anions. The electrosorption valency evaluated has a constant value in the potential region studied. It was concluded that the formed effective surface dipole is significantly screened by the solvent molecules and the metal electron gas.

Slip Calculation and Analysis for Four-wheel Drive Tractors

The objective of the research of tires was to determine the dynamic rolling radius and to apply it to wheel slip calculations with special respect to vertical wheel load and to tire inflation pressure. It is typical of mechanical four-wheel drive tractors that there is a definite additional power in the tractor power chain. This additional power is dependent on the difference between the front wheel and rear wheel peripheral speeds. Further-more, the purpose was to determine the effect of additional slip on four-wheel drive tractors operated without drawbar pull. Experiments were performed on asphalt surfaces and fields. A new measurement method was developed, and a device was constructed for the implementation of three tractor wheel drive operational modes (four-wheel drive, rear-wheel drive and front-wheel drive). As the result of the experiments, a relationship was found to describe the dynamic rolling radius for low-profile radial tires tested on rigid road surfaces. On this basis, the classical slip calculation method was modified. This phenomenon appears only on hard roads and soil surfaces with high adhesion coefficients and only within the low drawbar pull range.