Diagrams Of Characteristics Research Articles

Tensile testing of composite elastomer specimen

Composite elastomers are polymers capable of large reversible highly elastic deformations over a wide temperature range. Production of elastomeric composite materials is one of the intensively developing areas of industry and science, the aim of which is to find materials ready to work in both domestic and extreme operating conditions. When creating new composite polymers, magnetically active elastomers, there are a number of physical and mechanical requirements for material characteristics that need to be checked on testing machines during tensile and compressive testing of specimens. These requirements include: elasticity, insignificant residual deformations under various test modes up to material rupture in tension. The specified requirements were tested on an automated testing machine in various modes. The diagrams of linear and nonlinear characteristics of tensile stresses of the specimen depending on the strain values up to the moment of its rupture were constructed and analyzed. The analysis of the constructed hysteresis loops at stretching - contraction of the specimen showed the possibility of its use as a shock-absorbing material. Establishing the relationship between the tensile forces and the resulting deformations, including the effect of a strong magnetic field on the material, is important for further work on selecting the most appropriate range of use of this material for various conditions of its application.

Physical Mechanisms and Conditions of Excitation of Vibratory Combustion of Solid Fuels

The authors have obtained experimental characteristics of the self-oscillating process of vibratory combustion of a solid fuel. As a result of the analysis of the obtained diagrams of amplitude and frequency characteristics of the self-oscillating process of vibratory combustion of a solid fuel depending on the position of the combustion zone in a Riecke tube, the fuel structure, and methods of charging, the authors have made the following assumption. Two types of processes coexist during the vibratory combustion of a solid fuel: for the fundamental harmonics of the oscillating process of low frequency, the energy approach known in the literature, and for harmonics of higher frequency, the vortex mechanism. Methods of experimental verification of this assumption have been developed and used. Experimental results confirm the proposed model of vibratory combustion of a solid fuel. A theoretical computational procedure for the development of vibratory combustion has been worked out. A theoretical study of the motion of a combustion wave at stochastic parameters of the process of heat release has been made.

PROVIDE STRENGTH OF THE UNDERGROUND PIPELINE SECTION WITH POSITIONAL DEVIATIONS AT COMPENSATING THE DEVICES INSTALLATION

Background. The presence of karst is one of the reasons for the deviation of the underground section of the pipeline, composed of straight pipes and insert curves, from the design position. In this case, it compresses in the longitudinal direction along the entire length of the calculated section, and the magnitude of the stresses exceeds their maximum permissible value from the standard influences and loads. Therefore, there is a need to make changes in the design of the pipeline, which could reduce its level of mechanical stress-strain state. Aims and Objectives. This paper is devoted to the study of meсhanical stress-strain state and ensure the strength of the underground part of the pipeline project in violation of the provisions of the instalation at the ends of the calculated area compensators designed for the removal of the longitudinal compressive forces in the pipe wall. Metods. Mechanical stress-strain state calculations of the selected section of the pipeline was carried out for two settlement options in violation of the provisions of the project: 1) the pipeline is made up of straight pipes and convex inserts; 2) in the middle part, where the pipeline has the greatest deviation from the project straight pipe replaced concave insert. In the third design option, the settlement is considered the pipeline composed of straight pipes and convex inserts after his return to the design position. Presented in the paper, diagrams and extremes mechanical stress-strain state pipeline characteristics are found by solving the problems: a) the ends of the calculated portion pinched the ground, so they cannot move in the longitudinally direction; b) on the ends of the counted site the compensators intended to relieve the longitudinal compressive forces in the pipe wall; c) due to failure in the functioning of the compensator the pipe can move in the longitudinal direction. Results. The calculation results are presented in the form of diagrams of the main characteristics of pipeline mechanical stress-strain state and tables, which are given extreme importance of these characteristics. Each version of the calculation concludes with an analysis of pipeline mechanical stress-strain state and evaluation of its strength in accordance with the requirements governing the operation of the main pipelines of the normative documents. As a result of the analysis of the mechanical stress-strain state and evaluation of the strength of the pipeline section, it is determined that if the design position in the pipeline is violated in which the rotation angles in the vertical plane are composed of the curves of the convex inserts, and the middle part is made of straight pipes, the installation of the compensators does not reduce the mechanical stress-strain state level, but rather leads to its growth and the emergence of potentially dangerous areas. The installation of the expansion joints reduced the mechanical stress-strain state level in the pipeline section, in which straight pipes in the middle part were replaced by concave inserts.

Modelling of Vibrations Subsystems of the Power Steering System Body

The main subject of deliberation was to determine the flexibility of the mechanical subsystems with constant cross section using the algorithm of exact and approximate methods. As far as the model subsystem of complex transverse vibrating mechanical system for the power steering system flexibility determinations were considered and after deliberation the approximate methods have been chosen. Analysing the diagrams of characteristics of confirmed system it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with the exact method. However the values of the characteristic in other areas are different. The difference between values of flexibility within two methods has the great influence on the result of complex systems. That is why it was necessary to correct the results of the approximate method.

Fundamental diagrams of pedestrian flow characteristics: A review

IntroductionThe dimensionality of pedestrian infrastructure facilities have a great influence on pedestrian movements and a considerable impact on natural environment of the facility. Understanding the pedestrian movements are crucial to estimate the capacity of the system accurately, especially in the transportation terminals such as railway stations, bus terminals, airports and so forth, where large crowd gathers and transfers. To have a safe and comfortable movement in normal situation and also a quick evacuation in emergency situation, pedestrian movement patterns should be analysed and modelled properly.PurposeOnce the behaviour of pedestrians is established in terms of speed and density with respect to the environment, even for the colossal systems, the pedestrian flow characteristics can be modelled by applying extremely efficient simulations. The main modelling element in the context of flow models is the fundamental relationship among speed, flow and density. The objective of this study is to review the fundamental diagrams of pedestrian flow characteristics developed for various flow types and geometric elements. This paper also discusses the design values of flow parameters and walking speeds of pedestrians at various facilities.MethodsIn order to achieve the goal of this paper, we presented a systematic review of fundamental diagrams of pedestrian flow characteristics developed by using various approaches such as field, experimental and simulation.ConclusionsAfter a thorough review of literature, this paper identifies certain research gaps which provides an opportunity to enhance the understanding of fundamental diagrams of pedestrian flow characteristics.

Beam elements as approximate models of vibrating mechanical subsystems of freight wagons

The complex mechanical system which is a subsystem of mechatronic system composed with many continuous mechanical elements having the same length and variable cross section, loaded by the harmonic force is analyzed. The main subject of deliberation was to determine the flexibility of the mechanical subsystem with constant cross section using algorithms of exact and approximate methods. Next, the comparison of methods and the correction of the approximate method has been made. The model of subsystem of complex transverse vibrating mechanical system of freight wagon was considered and after deliberation the approximate method has been chosen. The presented research of subsystems establishes the foundation to complex systems analysis with cascade structure. By analyzing the diagrams of characteristics of confirmed system it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with the exact method. However, the values of the characteristic in other areas are different. Therefore, there is the mistake within the approximate method, which while of studying the single system does not have any influence because in resonance areas the characteristic values of the system approach to the infinity. However, the difference between values of flexibility within two methods has the great influence on the result of complex systems. That is why it was necessary to correct the results of the approximate method.

Correction of Characteristics of Transverse Vibration Subsystems of Complex Mechanical or/and Mechatronic Systems

In this paper the application of analysis within transverse vibrating subsystem of complex or/and mechatronic systems by means of the exact and approximate methods were the main purposes of work. The second purpose - of the work was to solve the task of assignment of frequency-modal analysis within characteristics of mechatronic system. Classical and unclassical methods to solve this problem have been used to obtain the dynamical characteristics in the Gliwice research Centre. During the analysis of the diagrams of characteristics of confirmed system it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with exact method. However, the values of the characteristic in other areas are different. The main aim of this paper was to compare the transients of characteristics of mechanical subsystem within the transverse vibrating discrete – continuous mechatronic system, obtained by exact and approximate, that means Galerkins method and to answer to the question – if the method can be used to nominate the characteristics of mechatronic systems. The main subject of deliberation was to determine the flexibility of the mechanical system with constant cross section using the exact and Galerkin’s method. The problems presented in this paper, such as the analysis of subsystem of mechatronic and mechanical complex systems is however the introduction to the synthesis of transverse vibrating mechatronic systems with assumed frequency spectrum.

Dynamic Characterization of Free Torsional Subsystem by Galerkin’s Approximate Method and its Correction

Studying the diagrams of characteristics of complex subsystem of mechatronic one it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with exact method. However the values of the characteristic in other areas are different. Therefore there is the mistake of approximate method, which in case of studying the single systems does not have any influence because in resonance areas the characteristic values of the system approach to the infinity. However the difference in values of flexibility within two methods has the great influence on the result of complex systems. The main subject of deliberation was to determine the flexibility of the complex system with constant cross section using the exact and approximate that means Galerkin's method. The mechanical and/or mechatronic system composed from many mechanical subsystems having the same length and variable cross section, loaded by the focused moment was analysed. One case of attachment the complex system that means free torsional vibrating bar were examined. That why it was necessary to correct the results of approximate method. The problems presented in this paper, that means the analysis of subsystem of mechatronic and mechanical complex systems is however the introduction to the synthesis of torsional vibrating mechatronic systems with assumed frequency spectrum.

Fatigue Behaviour of Carbide Precipitation Hardened Austenitic Steels

The paper presents the results of investigations of the microstructure and fatigue behaviour of two newly invented Cr-Ni and Cr-Ni-Mn austenitic steels of 13/13 and 12/8/8 type strengthened through carbide particle precipitation. The specimens of the investigated steels were subjected to tests after heat treatment, i.e. solution heat treatment (1200°C/0.5 h/water) and aged at a temperature of 700°C for 12 h, with cooling in air. The heat treated specimens were then subjected to low-cycle fatigue tests (LCF), carried out at room temperature and at an increased temperature of 600°C. Diagrams of fatigue characteristics of the investigated steels at room temperature as well as at elevated temperature have been worked up. It has been found that during low-cycle fatigue tests, at both temperatures, the investigated austenitic steels indicated a fatigue softening effect. The results of LCF at room temperature showed that the fatigue durability (Nt) of both austenitic steels is located in the range 0.8÷1.3×103 cycles. The results of low-cycle fatigue tests at an increased temperature 600°C indicated that the fatigue durability of the investigated steel was lower, and is located in the range Nt = 0.5÷0.6×103 cycles. It has been pointed out that the investigated austenitic steels are characterized by a stability of structure in conditions of cyclic fatigue.

Dynamical Charactersitics of the Discrete – Continuous Mechatronic System Obtained by Means of Exact and Approximate Methods

The research of subsystems establishes the foundation to complex systems analysis with cascade structure. Analysing the diagrams of characteristics of confirmed system it has been determined that in case of approximate method the resonance frequencies cover with those which have been determined with exact method. However the values of the characteristic in other areas are different. The main aim of the paper is to study the dynamic characteristic of the discrete continuous mechatronic system determined by exact approximate, that means Galerkin's method for torsionally vibrating complex mechanical subsystems. The system composed from many subsystems having the same length and variable cross section, loaded by the focused moment was analysed. The main subject of deliberation was to determine the flexibility of the mechanic system with constant cross section using the exact and approximate Galerkin's method. Next the method comparison and the correction of approximate method where made. As far as the mechatronic system flexibility determinations concerned the Galerkin's method has been chosen. The analysis of subsystems of mechatronic and mechanic complex systems is however the introduction to the synthesis of torsionally vibrating mechatronic systems with assumed frequency spectrum.

Ionized gas boundary layer on a porous wall of the body within the electroconductive fluid

This paper investigates the ionized gas flow in the boundary layer, when the contour of the body within the fluid is porous. Ionized gas is exposed to the influence of the outer magnetic field induction Bm = Bm(x), which is perpendicular to the contour of the body within the fluid. It is presumed that the electroconductivity of the ionized gas is a function only of the longitudinal coordinate, i.e. ? = ?(x). By means of adequate transformations, the governing boundary layer equations are brought to a generalized form. The obtained generalized equations are solved in a four-parameter localized approximation. Based on the obtained numerical solutions, diagrams of important physical values and characteristics of the boundary layer have been made. Conclusions have also been drawn.

Application of acoustic full wavetrains for the determination of lithology, reservoir and mechanical parameters of formation1

AbstractThe significant development in acoustic full waveform logging during the last ten years has made it increasingly possible for log analysts to determine the physical properties of a rock formation in situ.Parallel to the methods applied to a single wavetrain during seismic processing, the new techniques, used for sets of wavetrains, have been successfully tested with acoustic full waveforms. Instantaneous characteristics analysis is included in this group of methods. This approach, leading to qualitative and quantitative interpretation, reveals the influence of small changes in physical properties on acoustic full wavetrains.Applications of complex acoustic waveform analysis for the determination of inhomogeneous zones are presented. Colour diagrams of instantaneous characteristics are used for the detection of fractured regions and slow formations with increased attenuation of acoustic waves.Results of the interpretation of individual acoustic full waveforms, based on cross‐correlation and spectral analysis, using the IDNP and IDNS computer programs, e.g. velocities of compressional waves, shear and Stoneley waves, are presented. Since the bulk density of the rocks was known, it was possible, using the velocities of P‐ and S‐waves obtained, to calculate the dynamic elastic moduli. We used the interpretation of acoustic full wavetrains to calculate porosity. The sonic porosity is compared to the porosity obtained from other logs and to that obtained from core sample analysis.The examples of acoustic full wavetrains were recorded in the Miocene sulphur‐bearing limestones in central Poland. Field measurements were made using the domestic prototype equipment for well log recordings in shallow boreholes.

Transition to stochasticity in the relativistic and the nonrelativistic versions of a dynamical system

Issues related to the transition to stochastic relativistic and nonrelativistic motion of electrons in an electromagnetic wave propagating obliquely to a uniform magnetic field, such as stability, structure of the diagrams of characteristics, and the morphology of the bifurcation sequence in the latter, are thoroughly investigated. The spatiotemporal distributions of the electron energies, relativistically and nonrelativistically, are also examined. Major, qualitative, as well as quantitative differences in all aspects related to the transition to stochasticity and energy distribution are found. These dramatic differences lead to the conclusion that, at least as far as stochasticity is concerned, the nonrelativistic approximation is invalid even in the weakest possible relativistic case

An offshore eddy in the California current system Part I: Interior dynamics

From January 9 to 17, 1981, detailed observations of the horizontal and vertical structure beneath one of the quasi-permanent semi-stationary mesoscale offshore eddy signatures in the California Current System (CCS) discussed by Bernstein, Breaker and Whritner (1977), Burkov and Pavlova (1980), and Simpson (1982) were made. The vertical sections of temperature and density show the presence of three-layer system. A subsurface warm-core eddy, whose diameter is about 150 km at the 7°C isotherm, is the dominant feature. A warm surface layer, which extends to a depth of 75 m, lies over the eddy. Between the warm surface layer and the subsurface warm-core eddy, there is a cold-core region which extends to a depth of about 200 m. There is a high degree of symmetry about the vertical axis of rotation. Vertical sections of salinity and dissolved oxygen are entirely different from sections of temperature and density. Diagrams of water mass characteristics confirm that the core of the eddy, found between 250–600 m, consists of inshore water from the California Undercurrent (CU). Below about 700 m, local waters from the Deep Poleward Flow (DPF) have been incorporated into the eddy. The observed distributions of properties (T, S, δ θ, O 2) are inconsistent with a single, local generation process for the eddy system. Radial distributions of angular velocity, normalized gradient velocity and relative vorticity support the use of a Gaussian radial height field as an initial condition in eddy models. Possible reasons why CCS eddies may differ dynamically from Gulf Stream rings are given in the text. At the time the observations were made, the system as a whole was in near geostrophic balance. Local geostrophic balance, however, cannot explain the observed distribution of properties and structure. The observed symmetry in the structure of the eddy system, chemical evidence (Simpson, 1984), biological distributions (Haury, 1984) and satellite images of the CC (Koblinsky, Simpson and Dickey, 1984) suggest that lateral entrainment of warm (oceanic) and cold (coastal) water into the upper two layers of the three-layer system by the subsurface eddy is a likely generation mechanism for the cold-core region. The coastal origin of the frontal structure along the northeastern quadrant and the oceanic origin of the frontal structure along the southwestern quadrant of the eddy system further support lateral entrainment as a generation mechanism for the cold core. This entrainment makes the CCS eddy system different from cold-core rings in the Gulf Stream and rather similar to some warm-core eddies found in the East Australian Current. The presence of CU water in the core of this eddy raises the question of how CU water was transported from the continental slope. Eddy generation mechanisms, other than baroclinic instability of the CC, may be required to explain the distribution, persistence, and core composition of offshore mesoscale eddies in the CCS. There is evidence that barotropic, in addition to baroclinic, processes may be important.

Constitution diagrams of metal-hydrogen systems and characteristics of hydride structure formation

Constitution diagrams of metal-hydrogen systems and characteristics of hydride structure formation

Gamma Cassiopeiae

The phenomena of emission-line stars are briefly outlined, and illustrated by a detailed description of the behaviour of Gamma Cassiopeia between 1929 and 1942, with a brief history of earlier and later observations. The description is based mainly on spectra taken at the Norman Lockyer Observatory, supplemented where necessary by data from other sources. A plate of objective prism spectra, and diagrams of the variable characteristics amplify the verbal description. Indications are mentioned of the physical processes involved in the outbursts, and of some unsolved difficulties of interpretation.

Activity of Paricutin Volcano from July 1 to December 31, 1951

Continuous observation of activity at Parícutin Volcano during the second half of 1951 was carried on mainly by Celedonio Gutiérrez and partly by Jesús Saldañna. The senior author was at Paricutin July 10–12, August 24–27, November 14–15 and 19–22, and December 27–30, for a total of 17 days during the period. Observatory data of Gutiérrez and Saldaña are presented in the diagrams of eruptive characteristics in Figures 1–3, and their records of weather conditions, rainfall, and ashfall are summarized in Table 1. Gutiérrez also mapped the monthly advance of the lava during the period, as shown in Figure 6. The senior author prepared the summaries in Table 2 and measured the changes in horizontal distances and elevations of points on the cone, as given in Table 3, besides interpreting the data, formulating the report, and commenting on the progress of the activity.

Activity of paricutin volcano from July 1 to December 31, 1949

The activity of Parícutin Volcano, State of Michoacan, Mexico, during the second half of 1949 is represented diagrammatically in Figures 1, 2, and 3. An explanatory discussion of these diagrams of eruptive characteristics and a description of the lettered noise types shown on them appeared in an earlier report on this Volcano [Wilcox, 1947], to which the reader is referred. Photographs of two common types of eruptive activity are shown as Figures 4 and 5, and a map outlining the monthly advance of lava during the period covered is given as Figure 6. Altitudes of different points on Paricutin cone are listed in Table 1, and weather data are summarized in Table 3.

Stabilization of carrier-frequency servomechanisms. I. Gain-phase margin diagrams of controller characteristics

In this first part a method of analysis of linear carrier-frequency systems is indicated, and applied in particular to electrical servomechanisms using a two-phase alternating-current control motor. The performance of such a servo, as regards stability and fidelity of the output as a copy of the input, depends on the action of a controller-demodulator unit including the motor. A calculation of the steady-state effect of a linear transfer characteristic on the suppressed-carrier modulated error signal makes possible application of the Nyquist stability criterion. The method does not require symmetry of the characteristics about the carrier frequency; if such symmetry is present the system is similar to an ordinary or d-c. servo. Thus a band-rejection network tuned to the carrier frequency has an approximate proportional plus derivative action on the envelope of the error signal, resulting in an “anti-hunt” or stabilizing effect similar to that due to a translated band-rejection characteristic (center at zero-frequency) in a corresponding d-c. servo. A procedure is given for construction of transformed Nyquist diagrams, or gain-phase margin diagrams. The effect of the correctly tuned band-rejection network, as well as the effects of bandwidth, of the network being tuned off the carrier frequency, of increasing gain or velocity constant k ν, and of the use of phase-shifting networks, are clearly shown by a series of such diagrams.