Estimation of the power of mechanical losses in the engine, transmission and wheels of car on the stand with running drums

The efficiency of a car is considered through the amount of energy loss spent on transmission from the engine to the driving wheels of the car. Analytical and experimental methods for assessing mechanical losses are analyzed. The advantages and disadvantages of road and bench tests of a car in free run modes are indicated. A description of the diagnostic equipment - a stand with running drums, used to simulate the movement of a car in laboratory conditions is given. The components of the necessary measuring equipment for recording the speed and torque on the wheels of a car are considered. The list of primary measuring sensors and main transducers is indicated, which transmit information to the computer. The results of the car run-out on the stand are given: the change in the instantaneous speed from time to time. The primary assessment of the regression model is made and the values of the coefficients are obtained by the method of least squares of deviations of the vehicle speed. A mathematical model for the subsequent processing of experimental data has been developed. The purpose of mathematical modeling is to separate mechanical losses by power units separately for the engine, transmission and car wheels. An assessment was made of the amount of energy losses in the stand itself with running drums. The characteristic of the stand has been obtained, which must be taken into account in the measurement procedure. The results of experimental studies for the GAZ-31029 car are presented. The results of the influence of the technical condition of transmission units and vehicle wheels on the value of the power of mechanical losses are presented. Car tire pressure studies have been conducted. The graphical dependences of the power of mechanical losses depending on the speed of the car are obtained. Recommendations have been developed for diagnosing the general condition of the vehicle by the amount of mechanical losses at the stand with running drums. The ways of further improvement of the method are given. The main conclusions based on the research results are formulated.

Creation of a Program for Finding an Approximating Function of the Obtained Experimental Results by the Method of Least Squares

When solving engineering and economic problems, it is often necessary to obtain mathematical relationships between various parameters characteristic of a given problem. As a rule, all physical experiments are reduced to measuring the dependence of a certain quantity u on one or several other quantities z1, z2,…, zn. The main task of using the least squares method as an approximation method from the point of view of approximate recovery of a function from its known values at a number of points is the selection of empirical formulas that allow an analytical presentation of the obtained experimental measurement data. This article discusses the problems of obtaining data and approximating a function by the least squares method using OOP.

STRUCTURAL FEATURE STUDY OF QUINOLINES DERIVATIVES WITH THERMODYNAMIC AND OTHER DESCRIPTORS: A QSAR APPROACH

Quantitative structure activity relationship analysis was performed on a series of thirty-three quinoline derivatives to establish the structural features required for angiotensin II receptor activity. QSAR models were derived by stepwise multiple regression analysis employing the method of least squares, using quantum chemical, thermodynamic, electronic and steric descriptors. Model showed best predictability of activity with cross validated value (q2 ) =0.7485, coeffi cient of determination (r2 ) =0.8734 and standard error of estimate (s) = 0.2690. These guidelines may be used to develop new antihypertensive agents based on the quinoline analogues scaffold.

The Rann of Cutch Earthquake of 21 July 1956

A seismometric study of the earthquake of 21 July 1956 in the Rann of Cutch, which caused destruction to life and property at Anjar, has been made. The epicentre and origin time have been determined by the method of least squares and are Lat. 23°20'N, Long 70000' E and 15h 32m 26S GMT respectively. The shock had a magnitude of 7 and a depth of focus of nearly 13 to 18 km.

Size distribution of Raindrops -Part I

Results of measurements of the size distribution of raindrops made at Poona during the months of August, September and October 1956, are reported in the form of a table showing the number of drops received at the ground level per m2 per sec for various ranges of diameter at 0.25 nterval, for different inten sities of precipitation ranging from 0 to 40 mm hr-l. Average values have been calculated and presented in the form of a similar table. Histograms showing the number, volume of liquid water, momentum and kinetic energy of raindrops per m2 per sec, against the raindrop diameters are given for six typical intensities of precipitation. The variation of the total number N, momentum M and kinetic energy E (in joules) of raindrops per m2 per sec with intensity of precipitation is shown graphically. By the method of least squares the following relations are obtained. N=710I0.47, M=165 I, and E = 2.8x10-3 I1.13, where I is the intensity of precipitation in mm hr-1.The results are presented in a form suitable for soil erosion problems. The data are confined to general rains.

Chebyshev approximation of the multivariable functions by some nonlinear expressions

A method for constructing a Chebyshev approximation of the multivariable functions by exponential, logarithmic and power expressions is proposed. It consists in reducing the problem of the Chebyshev approximation by a nonlinear expression to the construction of an intermediate Chebyshev approximation by a generalized polynomial. The intermediate Chebyshev approximation by a generalized polynomial is calculated for the values of a certain functional transformation of the function we are approximating. The construction of the Chebyshev approximation of the multivariable functions by a polynomial is realized by an iterative scheme based on the method of least squares with a variable weight function.

Determination of the Function of the Course of the Static Property of PAMs as Actuators in Industrial Robotics

Current efforts are focused on assembling new constructions while applying non-conventional actuators, for example, artificial pneumatic muscles, in engineering manufacturing processes. The reason is to eliminate stiffness and inflexibility of equipment structures that make sharing the working space of the technological equipment complicated. This article presents the results of experimental measurements of pressures in artificial muscles and rotations of the actuator with artificial muscles at various loads, using a testing device of an antagonistic actuator. The measurement results were used to create the function of the course of the static property of the antagonistic actuator with artificial muscles of the Festo type and to determine a mathematical model of the actuator dynamics, while applying the method of least squares.

On the fast approximation of point clouds using Chebyshev polynomials

Suppose a large and dense point cloud of an object with complex geometry is available that can be approximated by a smooth univariate function. In general, for such point clouds the “best” approximation using the method of least squares is usually hard or sometimes even impossible to compute. In most cases, however, a “near-best” approximation is just as good as the “best”, but usually much easier and faster to calculate. Therefore, a fast approach for the approximation of point clouds using Chebyshev polynomials is described, which is based on an interpolation in the Chebyshev points of the second kind. This allows to calculate the unknown coefficients of the polynomial by means of the Fast Fourier transform (FFT), which can be extremely efficient, especially for high-order polynomials. Thus, the focus of the presented approach is not on sparse point clouds or point clouds which can be approximated by functions with few parameters, but rather on large dense point clouds for whose approximation perhaps even millions of unknown coefficients have to be determined.

Analysis and Forecasting Electricity Production of Kyrgyzstan by the Method of Least Squares

The object of research in this article is the electric power industry of Kyrgyzstan. Each country strives to have its own energy at the lowest price in comparison with other regions or countries, making the most of its regional natural energy resource. In the republic, the main energy resource is hydropower resources. Forecasting energy supply in Kyrgyzstan is an urgent task. The article examines the analysis of electricity production in Kyrgyzstan by the least squares method and shows that the provision of electricity production is highly dependent on electricity production rather than the price and demand for it.