Method of parametric analysis of reciprocating electric generators with permanent magnets

A method for the parametric analysis of electric generators of reciprocating motion with permanent magnets has been developed, which allows revealing the values of the parameters of the magnetic circuit (cross-sectional area) and the working winding (number of turns) at a given value of the efficiency, providing a minimum specific gravity of the generator. The method of parametric analysis of electric generators of reciprocating motion with permanent magnets consists of three stages. The first and second stages are the electromagnetic calculation of the generator: at the first stage, the main geometric dimensions of the magnetic system and the parameters of the working winding of the generator are determined; at the second stage, the verification of the electromagnetic calculation of the generator, calculation of the nominal mode, calculation of the efficiency and assessment of the thermal state of the generator are fulfilled. At the third stage, a parametric analysis of electric generators of reciprocating motion with permanent magnets with specified constraints is carried out, as well as the refinement of the geometric dimensions and configuration of the magnetic system of the generator using a two-dimensional finite element model of the magnetic field. As a result, to ensure better use of the electrical steel of the magnetic circuit of the generator and thereby reduce its mass, the most saturated areas and areas, which are characterized by low values of the magnetic field strength, are determined. Distinctive features of the proposed technique are: the use of a minimum specific gravity of electric generators of reciprocating motion with longitudinal, transverse or combined changes in the magnetic flux passing through the working winding as an objective function; combined approach to electromagnetic calculation; taking into account the influence of the operating temperature on the parameters of the permanent magnet, as well as overheating of individual parts of the generator.

The Friction of Structurally Modified Isotactic Polypropylene

The purpose of studies was to analyse an impact of heterogeneous nucleation of modified isotactic polypropylene (iPP) on its tribological properties. The iPP injection molded samples, produced by mold temperature of 20 and 70 °C, were modified with compositions of two nucleating agents (NA’s), DMDBS creating α-form and mixture of pimelic acid with calcium stearate (PACS) forming β–phase of iPP, with a total content 0.2 wt.% of NA’s. A polymorphic character of iPP, with both, monoclinic (α) and pseudo-hexagonal (β) crystalline structures, depending on the NA’s ratio, was verified. The morphology observation, DSC, hardness and tribological measurements as test in reciprocating motion with “pin on flat” method, were realized, followed by microscopic observation (confocal and SEM) of the friction patch track. It was found that Shore hardness rises along with DMBDS content, independent on mold temperature. The friction coefficient (COF) depends on NA’s content and forming temperature—for upper mold temperature (70 °C), its value is higher and more divergently related to NA’s composition, what is not the case by 20 °C mold temperature. The height of friction scratches and the width of patch tracks due to its plastic deformation, as detected by confocal microscopy, are related to heterogeneous nucleation modified structure of iPP.

Research on the Reciprocating Motion of the Man-Machine Indirect Piston and the Efficiency of Internal Friction

In the process of technological progress and development, many industries are moving towards artificial intelligence (AI) technology, which is a construction and combination of multi-thinking technology. But in terms of structure, material development and diversification, the source of ideas is still inseparable from the natural world. Therefore, when faced with solving problems, many scientists not only conduct in-depth research on changes in cells, tissues and expansion, to solve the multi-dimensional movement of current technology, but also non-destructively explore the thermal effects of friction. Self-generated lubrication or external additives are used to solve the demand, so that the reciprocating movement of the piston can be more effective, and each cycle can be achieved. According to research and discussion, in each cycle, heat engine and cooling, speed movement frequency and lubrication method are different, which not only makes the piston have different effects, but also the reaction and sensitivity will greatly change, which makes it necessary to stop resting. Therefore, this research is primarily aimed at exploring the reciprocating motion of the human-machine “Indirect piston” and the efficiency of internal friction. The purpose is to have a more in-depth study of the piston theory, so as to have a deeper foundation for the movement of derived multi-dimensional angles in the future. In the future, there will be better development in injection, piston mechanism, and lubrication.

New Designs of Magnetic Fluid Seals for Reciprocating Motion

The operating conditions of magnetic fluid seals during reciprocating motion are so different from those observed in rotating motion that the use of their conventional structures for reciprocating motion seals yields no good results. The analysis of the sealing mechanism of magnetic fluid seals in reciprocating motion shows that the operation of these seals is affected by the carry-over phenomenon and magnetic fluid film deformation in the sealing gap, which depends on the velocity of the reciprocating motion. The reduced amount of magnetic fluid in the sealing gap caused by the reciprocating motion of the shaft is the main reason for seal failures. The paper presents a short characterisation of magnetic fluid sealing technology, the principle of sealing, the operation of the magnetic fluid and the seal failure mechanism in linear motion of the shaft. Moreover, some new structural designs of hybrid seals, being combinations of typical hydraulic seals with magnetic fluid seals for reciprocating motion, and some examples of magnetic fluid sealing structures for hydraulic cylinders and piston compressors which have practical application values are presented.

Coefficient of mutual overlap in metal-polymer tribosystems

The polymer hybrid material under study is used as an antifriction coating of the friction contact surface. The experimental studies have been carried out on a special test bed with a reciprocating motion of the tribosystem in conditions of a mutual overlap coefficient less than one. The influence of the most important operational parameters, such as temperature, operating wear and wear rate, has been studied. The temperature was determined in the area of fixing the coating on a metal substrate, since the adhesive strength of the coating ensures the operability of this tribosystem. In addition, for the maximum friction modes, such standard parameters as the wear intensity and service life have been calculated. The wear resistance class has been set.

Resistance of PLA Material Prepared By Additive Technology

The article studies the surface properties of PLA material prepared by additive technology, i.e. 3D printing. Samples with a square test area were printed by FFF technology. After 3D printing, the surface texture of the samples was evaluated in terms of microgeometry.Tribological tests were performed on the samples. The surface of the samples was cyclically stressed with the same load, always on the same path. Cyclic loading of the surface was performed on a UMT Bruker tribometer. The tribological properties between the sample surface and the test specimen in the shape of a ball were studied during the reciprocating motion. In particular, the coefficient of friction was measured and evaluated. The ball material was PTFE and Polypropylene.The wear parameters of samples and balls were documented and evaluated. The results of the tests are the load dependencies on the wear of the PLA material and the test specimens.

Evaluation of Curved Canal Transportation Using the Neoniti Rotary System with Reciprocal Motion: A Comparative Study

The ideal root canal preparation is where the original canal morphology is maintained during the biomechanical preparation. Preparation of curved canals has always been a challenge to clinicians. Better results have been suggested for a single NiTi instrument with reciprocating motion than the conventional continuous rotation method in the preparation of curved root canals. Although the Neoniti rotary system is not suggested to be used with reciprocal motion, running a pilot study, we found that it could be possible. The present study aimed to investigate if shaping curved canals using the Neoniti rotary system with reciprocal motion leads to better results in terms of root canal transportation. One hundred acrylic j-shape canal simulator endoblocks were used in this study. Five preparation sequences were applied: GPS followed by A1#20 (GPS + A1#20), GPS followed by A1#20 and then A1#25 (GPS + A1#20 + A1#25), GPS followed by A1#25 (GPS + A1#25), hand file followed by A1#20 (hand file + A1#20), and GPS followed by A1#20 (with reciprocal motion) (GPS + A1#20(reciprocal)). Pictures were taken from blocks once before and once after preparation from two dimensions. Before-and-after pictures were superimposed in Photoshop software. Measurements were performed in Digimizer. The number of autoreverses and pecking motions was recorded after reviewing the recorded videos. Data were analyzed in SPSS, version 26. A p value of less than 0.05 was considered statistically significant. The group GPS + A1#20 + A1#25 had more transportation compared with the others, at apical, middle, and coronal thirds not only in the frontal view but also in the lateral view. Other groups were not significantly different. The number of peckings and autoreverses was significantly less when A1#25 was used after GPS and A1#20. When A1#20 was used with reciprocal motion, it had less peckings compared with the same file with continuous rotation, and no autoreverses were observed in that group. Using Neoniti files with reciprocal motion might result in less instrument fatigue and favorable results, with respect to canal anatomy preservation. Using A1#20 before A1#25 also will decrease the stress on the instrument during preparation. However, this may lead to significantly more canal transportation.

Effect of clearance on volumetric efficiency in 2D piston pumps

In order to solve the limitations of the friction pairs in axial piston pumps on rotational speed and mechanical efficiency, a 2D piston pump whose 2D piston has two-degree-of-freedom motions of rotation and reciprocating motion was proposed by the author team. The volumetric efficiency of 2D pumps predicted by the original volumetric efficiency model is higher than the experimental results. A new mathematical model of the volumetric efficiency is researched by considering effect of clearance between the cone roller and the guiding rail. In previous studies, the volumetric losses of the 2D pump were considered to be composed of leakage and compressibility loss. However, it is found that the effect of the clearance on the volumetric efficiency in 2D pumps is greater than that of leakage and compressibility loss. The experimental results show that the difference between the prediction of the new model and the volumetric efficiency of the tested pump with 0.19 mm clearance is reduced from 8% to 1.5% comparing with the original model. The volumetric efficiency of the tested pump without the clearance is 96.5% at 5000 rpm rotational speed and 8 MPa load pressure.