Rectilinear Part Research Articles

Geometric approach to define a railway plan model

The construction of new railway lines is based on the railway plan. There are various ways to draw up a railway plan. The basis of all railway plans is a scheme of geometric point locations, the projection of the center of gravity of the carriage is on a horizontal plane and consists of a single flat line. The railway plan consists of linear and curved parts connecting straight sections. However, the curves determining the position of the rails of the railway track in the curved part will be spatial. To extinguish the centrifugal forcearising in the curved part of the road, an external rail rises. In this case, the elevated curve representing the outer rail becomes spatial. Therefore, in the work, it is proposed to draw up a plan of a railway track as two curves, one of which is flat, and the other depicts an external spatial rail. In this case, the distance between the ends of the rectilinear parts and the angle between the rectilinear parts are selected as the main parameters. In the work, for the simplest case, when both linear parts belong to the same horizontal plane, it is proved that the curved part is a spatial curve. The curvature of the required curve was determined and a dynamic system was constructed, the solution of which would be a curve that satisfied the technical conditions presented for the railway route. This dynamic system is proposed as a mathematical model of the railway route. In the rectilinear parts, the railway plan is straight on a horizontal plane. The curve of the road should be spatial.

Influence of Laser Welding Modes along a Curved Path on the Mechanical Properties and Heterogeneity of the Microstructure of 316L Steel Plates.

The results of experimental studies in the manufacture of components of the supporting structure of the first wall panel, carried out as part of the manufacture of a model of the International Thermonuclear Experimental Reactor (ITER) using laser welding technology, are presented. The influence of laser welding modes on the quality of formation, microstructure characteristics, and mechanical properties of a welded joint made of 10 mm thick 316L steel was studied. A coaxial nozzle was designed and manufactured to protect the weld pool with a curved trajectory. The mechanical properties of the welded joint are 98-100% that of the base metal, and the microhardness of the welded joint and base metal is in the range of 180-230 HV. It was established that the lower part of the weld metal on the fusion line has transcrystalline grains and differs in δ-ferrite content; due to a high welding speed, the ratio of the depth to the width of the welding seam is 14 times. The width of the rectilinear part of the seam is 15-20% larger than its curved part.

Аналіз науково-технічних інновацій в галузі машинобудування з виявленням закономірності впливу технологічних параметрів

Based on the analysis of scientific and technical information, it established that today layered metals are one of the most modern and promising materials used in all branches of mechanical engineering and national economy. The use of bimetals allows you to achieve significant cost savings, obtain materials with unique properties, increase production efficiency and competitiveness of a wide class of parts and equipment. The purpose of the article is to analyze the methods of determining the stress state of a workpiece with heterogeneous mechanical characteristics in the process of plastic deformation and to determine the stress-strain state when drawing rectangular parts from bimetals. As a result, of unequal deformation conditions in different parts of the contour, as well as anisotropy of the mechanical properties of the workpiece material, the height of box-shaped parts is even more uneven than the height of axisymmetric parts obtained by drawing. Therefore, in the manufacturing process of such parts, cutting of the uneven edge provided. The trimming allowance depends on the relative height of the part. The bigger it is, the bigger the allowance. Since the flange naturally thickens during drawing in the corner sections of the part contour, this phenomenon taken into account when determining the gap between the punch and the die of the drawing die: in the corner sections, the gap should be greater than in the straight sections of the die contour. Extrusion of box-shaped parts from bimetals causes even greater unevenness of deformations. A different amount of deformation of the layers of the bimetallic work piece imposed on the general sign change of the voltages, which causes bending and warping of the rectilinear parts of the semi-finished product, and therefore, the impossibility of obtaining a high-quality product. Based on the analysis of the stress-strain state of the workpiece in the process of drawing bimetal. The following provisions are proposed: if the mechanical properties of the metal layers do not differ - the two-layer metal behaves like a single-layer, then the ratio of the thicknesses of the two-layer metal does not change after drawing; if the mechanical properties of the layers differ, then the ratio of the thicknesses of the two-layer metal changes after drawing. Thus, when the ratio σs1/σs2 decreases, the thickness of the first layer, which has lower mechanical properties, decreases at the output; the thickness ratio after drawing also depends on the initial ratio of metal thicknesses. Based on the analysis of the stress-strain state of the work piece during the extraction of box parts, the following methods and techniques have been determined for obtaining high-quality parts by extraction and saving material: use metals with similar mechanical properties; the desire to increase the curvature of the corner zones of the work piece; to calculate the dimensions of the work piece for the hood with the involvement of modern mathematical apparatus (potential method); use brake media instead of brake ribs; affect the center of deformation, increasing the effect of unloading tangential stresses.

Improvement of the Process of Separation of Cotton Fiber from Seeds

The differential equation, obtained as a result of the theoretical study of the movement of the bare seed on the surface of the grate of the saw gin, made it possible to determine the trajectory of the movement of the seed. The rib is one of the main working bodies of the saw gin. It serves for the free passage of the saw blades through it into the working chamber, for the withdrawal of the fiber caught on the saw teeth after separating it from the seed. A number of studies have been carried out to improve the working elements of the saw gin. The purpose of the research is to create the possibility of timely withdrawal of bare seeds from the working chamber of the saw gin by creating a concavity on the working surface of the grate. The use of the Euler equation for the movement of bare cotton seed along the grate contour, taking into account its speed V, density ρ, pressure P, made it possible to obtain a graph of seed distribution along the grate contour. An experimental 30-saw gin was developed and manufactured, the research carried out on it allowed to determine the rational parameters of new grates, which are recommended for introduction into production. The dependence of the location of the rectilinear part of the general contour on the shape of its convexity and concavity is determined. Based on the above equations, using separate functions, we present the view of the grate profile in the coordinate system modeled on the MAPLE-17 program.

Tillage unit with new design working bodies for minimal tillage

The design of the tillage unit is presented, with new working bodies made in the form of a holder with rectilinear and oval parts, the rectilinear part is made in the form of a bar made at an acute angle to the horizontal surface and rigidly fixed on a rack with the possibility of dismantling. The lower part of the holder is shaped like an elongated ellipse, the upper oval part of which is a ripper, the lower-a slitter. The height of the ripper and the slitter is the same, on their butt line on the side of the toe, a groove is made for the pointed paw of the cultivator. On the back side of the paw, a groove is made for the holder, while the ratio of the length of the grooves of the paw and the holder is 1:3. The new design of the working body will improve the quality of tillage and water-air balance, increase crop yields and reduce fuel consumption.

Theoretical Study of the Movement of Cotton Seed Flow along the Contour of the Rib

Improving the efficiency of the process of separating fiber from cotton seeds by improving the working chamber of the gin is one of the important issues. The main way to increase the efficiency of sawn gin is to increase the fiber content in the mass of seeds in the working chamber with a uniform decrease in its density. This can be achieved by using grates with a concave working surface, which serves to move the seeds away from the rotating saws and accelerate the release of bare seeds from the working chamber. The article discusses the movement of seeds on the concave surface of the grate and determines the rational parameters of their working part. The article explores the proposed grate model, consisting of four geometric shapes, provides an analytical analysis of the geometric types. The dependence of the location of the last rectilinear part of the general contour on the shape of its convexity and concavity is determined. Cotton seeds move along the contour in the form of a stream. We assume that the thickness of the flow along the contour is constant and equal. We compose a unique equation of the flow in each section of the circuit. To determine the state of the flow, we denote its velocity, density and pressure in each section, respectively. Let us determine the flow motion along the contour with respect to the arc.

An External Meniscus on a Thin Fiber Whose Profile Has Separate Rectification Points

We clarify the limits of applicability of the previously developed asymptotic method for defining the configuration of an external meniscus of a liquid on a thin fiber. As was found out earlier, if the fiber material is fully wet, while the fiber profile has rectilinear parts, then the mentioned method gives unsatisfactory results when being applied near the fiber, because it leads to the infinite growth of the contact line. We prove that in the case when a smooth convex fiber profile contains only separate rectification points, the asymptotic approach predicts the meniscus shape, as a whole, satisfactory. However, it inadequately describes the behavior of the contact line near rectification points of the profile, namely, it gives a line with breaks instead of an expected smooth one.

Thermal elastic deformation of the layered covering on the concave part of a road

The problem on numerical investigation of thermo-elastic deformation of a layered coating on the concave and rectilinear road parts is stated. The constitutive equations are formulated, their finite-element analogues are constructed. The load versions at different values of geometric, structural, and temperature parameters are taken into account.The influence of the door curvature on redistribution of the stress fields under action of thermal perturbations are analysed. As in a uniform heating (or cooling) the curvilinear layers change their lengths in different manure, then it can be supposed that even under small concentration in all direction of the road body are exhibited. At that, for the rectilinear segments of the roads, the stress, normal to the road surface, practically are equal to zero. With the curvature enlargement, the enlargement of tensile normal stress throughout the road length is observed. This lead to enlargement of the probability of the breakaway of the first layer from the second one.It is shown by numerous calculations that the peak values of the longitudinal ensile forces in the top layer and shear forces localized between the first and second layers can be a cause of the initial road destruction observed in practice and formation of transversal cracks.

Fractional Differential Generalization of the Single Particle Model of a Lithium-Ion Cell

The effect of anomalous diffusion of lithium on the discharge curves and impedance spectra of lithium-ion batteries (LIB) is studied within the fractional differential generalization of the single-particle model. The distribution of lithium ions in electrolyte and electrode particles is expressed through the Mittag–Leffler function and the Lévy stable density. Using the new model, we generalize the equivalent circuit of LIB. The slope of the low-frequency rectilinear part of the Nyquist diagram does not always unambiguously determine the subdiffusion index and can be either larger or smaller than the slope corresponding to normal diffusion. The new aspect of capacity degradation related to a change in the type of ion diffusion in LIB components is discussed.

Diagnostics of the Engineering State of Steam Pipelines of Thermal Power Plants by the Hardness and Crack Resistance of Steel

We propose a nondestructive method for the diagnostics of the current state of heat-resistant steels after long-term operation in the steam pipelines of thermal power plants (TPP). It is based on measuring the sizes of ferrite grains and the hardness of 15Kh1M1F heat-resistant steel directly on the pipe surface and on the use of the deduced relationship between these characteristics (of the Hall–Petch type). The plot of this relationship contains two rectilinear parts. The first part agrees with the physical ideas concerning the correlation between the grain size and the strength (hardness) of the material. The second part with a rapid decrease in the hardness of steel is connected not only with the subsequent changes in the microstructure of steel but also with the development of the in-service defects scattered in the volume of the metal. To determine the limiting state of degraded steel, we used one of the parameters of fracture mechanics, namely, the effective threshold amplitude of the stress intensity factor (SIF) ΔKth eff determined with regard for the effect of fatigue crack closure. The application of this parameter is substantiated by the detected inversion of the influence of hydrogen on ΔKth eff (from positive to negative) observed as the degree of in-service degradation of steel increases. The indicated inversion is caused by the transformation of the mechanism of fatigue crack growth in the subthreshold part of the fatigue crack growth diagram from transgranular (caused by microshears at the crack tip in each loading cycle) into a brittler mechanism accompanied by the formation of intergranular fragments of mode I fracture in the damaged areas. Therefore, the threshold of cyclic crack-growth resistance corresponding to this inversion is taken as the critical value $$ \varDelta {K}_{\mathrm{th}\;\mathrm{eff}}^c $$ below which the probability of brittle fracture of the exploited steel becomes much higher. By using the constructed correlation dependence between ΔKth eff and the hardness of the metal and the determined critical value $$ \varDelta {K}_{\mathrm{th}\;\mathrm{eff}}^c, $$ we estimate the critical value of hardness. Below this value, the hazard of uncontrolled brittle fracture noticeably increases due to the presence of defects scattered in the bulk of the metal.

Use of Vegetable Fibers as Reinforcement in the Structure of Compressed Ground Bricks: Influence of Sawdust on the Rheological Properties of Compressed Clay Brick

The present study aims at understanding the rheological behavior of Compressed Ground Bricks (CGB). It thus uses as raw materials the clay and the sawdust which are an industrial waste with the multiple consequences on the environment. The composites elaborate clay-sawdust of wood are bricks intended to be used like fill material of the walls. Their mechanical properties were studied in order to place at the disposal of the users, of competitive materials; but a particular stress was laid on their behavior at the rupture. Thus, the study shows that the CGB containing clay only have flexural strength and compressive strength respectively of 1.3 MPa and 2.6 MPA. When one adds the sawdust to it, these resistances grow to reach optimal values, before decreasing. For the flexural strength, optimal resistance is of 1.4 MPa, for a content of sawdust of 20%. For the compressive strength, the optimum is reached to sawdust 15% with a resistance of 4.4 MPa. The study of the relations stress-strain shows that the curve of the CGB without sawdust has only one pace rectilinear before the rupture (elastic range); these bricks thus have a fragile behavior. The addition of the sawdust to clay confers on the CGB a quasi ductile behavior characterized by curves which present initially a rectilinear part (elastic range), followed by a curvilinear part (plastic range). One can also note that the addition of the sawdust cause a drop in the dry density of bricks.

Fast ion motion in the plasma part of a stellarator-mirror fission–fusion hybrid

Recent developments of a stellarator-mirror (SM) fission–fusion hybrid concept are reviewed. The hybrid consists of a fusion neutron source and a powerful sub-critical fast fission reactor core. The aim is transmutation of spent nuclear fuel and safe fission energy production. In its fusion part, a stellarator-type system with an embedded magnetic mirror is used. The stellarator confines deuterium plasma with moderate temperature, 1–2 keV. In the magnetic mirror, a hot component of sloshing tritium ions is trapped. There, the fusion neutrons are generated.A candidate for a combined SM system is a DRACON magnetic trap. A basic idea behind an SM device is to maintain local neutron production in a mirror part, but at the same time eliminate the end losses by using a toroidal device. A possible drawback is that the stellarator part can introduce collision-free radial drift losses, which is the main topic for this study. For high energy ions of tritium with an energy of 70 keV, comparative computations of collisionless losses in the rectilinear part of a specific design of the DRACON type trap are carried out. Two versions of the trap are considered with different lengths of the rectilinear sections. Also the total number of current-carrying rings in the magnetic system is varied. The results predict that high energy ions from neutral beam injection can be satisfactorily confined in the mirror part during 0.1–1 s.The Uragan-2M experimental device is used to check key points of the SM concept. The magnetic configuration of a stellarator with an embedded magnetic mirror is arranged in this device by switching off one toroidal coil. The motion of particles magnetically trapped in the embedded mirror is analyzed numerically with use of motional invariants. It is found that without radial electric field particles quickly drift out of the SM, even if the particles initially are located on a nested magnetic surface. We will show that a weak radial electric field, which would be spontaneously created by the ambipolar radial particle losses, can make drift trajectories closed, which substantially improves particle confinement. It is remarkable that the improvement acts both for positive and negative charges.

On registration of spontaneous electromagnetic emission of lithosphere within lengthy salt adit

Results of measurements of impulse current of electromagnetic emission within frequency range 2,5-50kHz (by 3 dB level) in rectilinear horizontal part of natural salt 700 m long adit situated at the depth of 260m and without any technical sources of noise have been presented. Registration of impulse current of emission at the site of observation located at the surface above the adit was being conducted synchronously and by the instrument of the same type. In addition non-synchronous measurements of impulse current along the profile situated on the surface under acute angle to the course of the adit have been carried out. The component of spontaneous electromagnetic emission of lithosphere origin has been distinguished in the frequency range under consideration without noise bar from the sources of atmosphere-ionosphere-magnetosphere origin. Comparative analysis of impulse current records obtained at the day surface and in the adit with the depth exceeding the thickness of the skin-layer within the frequency ranges 2,5-50 kHz has been given and their geological-geophysical interpretation has been proposed.

Proton radiography: A new method and its implementation

A radiographic facility, placed in the initial rectilinear part of the injection channel, which is intended for transporting a proton beam from U-70 into an accelerator-storage complex, is described. It is designed for energy 50 GeV with field of view 60 mm and makes it possible to obtain an image of objects with optical thickness to 400 g/cm2 with resolution 100 μm. The first static and dynamic experiments performed in our country at 50 GeV have shown the advantages of pulsed radiography in studying fast processes in ultradense media.

Automated Sequential‐injection Chemiluminescence Determination of Glucosamine Sulphate via Luminol‐Hydrogen Peroxide System

AbstractA highly sensitive automated sequential‐injection chemiluminescence (SIA‐CL) method for determination of glucosamine sulphate (GLS) was developed. The goal of the present work is the evaluation of the enhancement effect of the investigated drug glucosamine sulphate on the chemiluminescence reaction between luminol and H2O2 in alkaline medium of 1.0 × 10−2 mol L−1 sodium hydroxide at pH 11. The experimental conditions affecting the CL reaction such as the sequence of the reagents, concentrations, flow rate and aspirated volumes of reactants were systematically investigated and optimized. Under optimum conditions 50 μL of 1.0 × 10−3 mol L−1 luminol, 30 μL of a GLS test solution and 50 μL of 1.0 × 10−2 mol L−1 H2O2 were used and the luminescing zone was pushed into the detector at a flow rate 100 μL s−1. The proposed method recorded high sensitivity, accuracy and simplicity that could be clarified as linear concentration range 1.0‐2000 ng mL−1 with rectilinear part (r = 0.9992, n = 9) and limit of detection 0.3 ng mL−1, along with relative standard deviation 1.3%. It was found that the developed method can be used directly to determine the investigated drug GLS in its pharmaceutical dosage forms and in spiked serum and urine by diluting the samples for a 1000 fold. The obtained results were statistically analyzed and compared with those obtained by the reported method.

Estimation of the admissibility of circular-crack-type defects in the zone of welded field joints of main pipelines

We have considered welded joints of rectilinear parts of underground or overground (in embankment) pipelines with point defects, which are modeled by internal circular surface cracks. We have determined their stressed state induced by the action of internal pressure, temperature drop between the mounting and operation temperatures, and technological residual stresses. On the basis of the two-parameter criterion of the mechanics of brittle–viscous fracture, with the use of failure assessment diagrams, we have calculated the coefficients of safety margin of such a part of the pipeline with a crack in the weld and the admissible defect sizes.

Development of the summer breeze circulation in the west part of the Black Sea

On the basis of the results of regional reanalysis of the atmospheric circulation presented with a resolution of 9 km, the process of formation of breezes is studied for the case of weak synoptic background activity in the rectilinear part of the west coast of the Black Sea for the period 01–04.07.2007. It is shown that the gravitational currents, breeze fronts, and intense internal waves are formed under these conditions in the troposphere during the daytime. The Hovmoller diagrams of the wind velocity and the maps of the vertical sections of potential temperature, vertical velocity of the air masses, and other parameters are presented. On the basis of these diagrams and maps, we obtain quantitative estimates of the wind velocity in the breeze and of the velocity of propagation of the breeze front and compare these estimates with the available literature data.

Nonlinear magnetic susceptibility and the spin glass state in the new nonstoichiometric spinel compounds Cu 1+ xCr 1.5+ ySb 0.5+ zSe 4+ t (where −0.02 ≤ x ≤ 0.01, 0.03 ≤ y ≤ 0.35, −0.2 ≤ z ≤ − 0.02, 0.01 ≤ t ≤ 0.08)

New nonstoichiometric spinel compounds Cu 1+ x Cr 1.5+ y Sb 0.5+ z Se 4+ t (where −0.02 ≤ x ≤ 0.01, 0.03 ≤ y ≤ 0.35, −0.2 ≤ z ≤ −0.02, 0.01 ≤ t ≤ 0.08) have been obtained with the aid of the solid-phase synthesis from the stoichiometric mixtures of the constituent elements. Six samples of these compounds with the different compositions have been chosen to the dc and ac magnetic susceptibility measurements. From the analysis of these measurements spin glass states have been revealed with the spin freezing temperature about 70 K for all the six samples. The magnetization measurements were performed for the same samples with the use of the induction method in the high stationary magnetic fields up to 14 T in the temperature range of 4.2–273 K. No sample under study reaches the saturation magnetization even at 14 T though they display a spontaneous magnetization, the latter existing at least up to 273 K. The temperature dependence of the dc inverse molar magnetic susceptibility reveals two different rectilinear parts which can be interpreted as related to two different Curie–Weiss temperatures: ∼68 and ∼45 K. It seems that these two temperatures correspond to two different types of the magnetically ordered clusters. The average effective magnetic moment is here equal to 2.35 μ B/ion pointing to the high defectiveness of both the crystal and magnetic structures. All the effects observed on both the magnetization and inverse molar magnetic susceptibility curves point to the appearance of the cluster spin glass states in the samples under study. Generally speaking, it is the statistical character of the substitution of the nonmagnetic antimony ions instead of the magnetic chromium ions which leads to the frustration of the orientations of the localized magnetic moments in the samples under study and in the consequence to the appearance of the spin glass states.

Free vibration analysis of composite rectangular membranes with a bent interface

This paper is an extension of the author's previous work that dealt with a composite rectangular membrane with an oblique interface. In the present study, a practical method is presented for the free vibration analysis of a composite rectangular membrane with two homogeneous regions, of which the interface consists of two rectilinear parts and is named ‘bent interface’. To the author's best knowledge, the vibration analysis of the composite membrane with this configuration is attempted for the first time in the paper. In order to extract the global system matrix of which the determinant gives natural frequencies, a special way of individually considering the two rectilinear parts of the bent interface and extracting local system matrices by means of applying the compatibility condition to each rectilinear part is revised. Case studies show that the natural frequencies and mode shapes obtained by the present method agree well with those given by exact solutions or FEM (ANSYS), even when a small number of base functions are used.

Deformation and Fracture Behaviour of Polymers. Engineering Materials Series

Deformation and Fracture Behaviour of Polymers. Engineering Materials Series