Bulletin of the Polish Academy of Sciences-Technical Sciences最新文献

{"title":"Estimation of random bio-hydrodynamic lubrication parameters for joints with phospholipid bilayers","authors":"Krzysztof Wierzcholski, Andrzej Miszczak","doi":"10.24425/bpasts.2021.135834","DOIUrl":"https://doi.org/10.24425/bpasts.2021.135834","url":null,"abstract":"This paper presents a new form of a mathematical estimation of stochastic bio-hydrodynamic lubrication parameters for real human joint surfaces with phospholipid bilayers. In this work, the authors present the analytical and stochastic considerations, which are based on the measurements of human joint surfaces. The gap is restricted between two cooperating biological surfaces. After numerous experimental measurements, it directly follows that the random symmetrical as well as unsymmetrical increments and decrements of the gap height in human joints influence the hydrodynamic pressure, load-carrying capacity, friction forces, and wear of the cooperating cartilage surfaces in human joints. The main focus of the paper was to demonstrate the influence of variations in the expected values and standard deviation of human joint gap height on the hydrodynamic lubrication parameters occurring in the human joint. It is very important to notice that the new form of apparent dynamic viscosity of synovial fluid formulated by the authors depends on ultra-thin gap height variations. Moreover, evident connection was observed between the apparent dynamic viscosity and the properties of cartilage surface coated by phospholipid cells. The above observations indicate an indirect impact of stochastic changes in the height of the gap and the indirect impact of random changes in the properties of the joint surface coated with the phospholipid layers, on the value of hydrodynamic pressure, load carrying capacity and friction forces. In this paper the authors present a synthetic, comprehensive estimation of stochastic bio-hydrodynamic lubrication parameters for the cooperating, rotational cartilage bio-surfaces with phospholipid bilayers occurring in human joints. The new results presented in this paper were obtained taking into account 3D variations in the dynamic viscosity of synovial fluid, particularly random variations crosswise the film thickness for non-Newtonian synovial fluid properties. According to the authors’ knowledge, the obtained results are widely applicable in spatiotemporal models in biology and health science.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"17 28","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135545571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On elastic contact problems of micro-periodic slant layered composite pressed by a rigid punch with a parabolic or rectangular shape","authors":"Piotr Sebestianiuk, Dariusz M. Perkowski, Roman Kulchytsky-Zhyhailo","doi":"10.24425/bpasts.2021.138091","DOIUrl":"https://doi.org/10.24425/bpasts.2021.138091","url":null,"abstract":". The paper presents an analysis of the influence of the shape of the rigid body pressed into the micro-periodic composite half-space on the examples of two punch shapes – parabolic and rectangular. The presented material is a layered body that consists of infinitely many thin alternately arranged homogenous layers. Layers of the presented composite are oblique to the boundary surface. Two cases of punch tip shape are examined – parabolic and rectangular. The presented problem has been formulated within the framework of a homogenized model with microlocal parameters and solved using the elastic potentials method and averaged boundary condition. Fourier integral transform method has been used to obtain the solution and the inverse integrals have been calculated numerically. Solutions in terms of contact pressure and maximum pressure characteristics were shown in the form of graphs.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"17 26","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135545573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trajectory tracking control of a mobile manipulator with an external force compensation","authors":"Mirosław Galicki","doi":"10.24425/bpasts.2021.137943","DOIUrl":"https://doi.org/10.24425/bpasts.2021.137943","url":null,"abstract":"This paper considers the problem of the accurate task space finite-time control susceptible to both undesirable disturbance forces exerted on the end-effector and unknown friction forces coming from joints directly driven by the actuators as well as unstructured forces resulting from the kinematic singularities appearing on the mechanism trajectory. We obtain a class of estimated extended transposed Jacobian controllers which seem to successfully counteract the external disturbance forces on the basis of a suitably defined task-space non-singular terminal sliding manifold (TSM) and the Lyapunov stability theory. Moreover, in order to overcome (or to minimise) the undesirable chattering effects, the proposed robust control law involves the second-order sliding technique. The numerical simulations (closely related to an experiment) ran for a mobile manipulator consisting of a non-holononic platform of (2,0) type and a holonomic manipulator of two revolute kinematic pairs show the performance of the proposed controllers and make a comparison with other well-known control schemes.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"14 27","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135545587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The relationship between the structural anisotropy of the PFA polymer/compressed expanded graphite-matrix composites and acoustic emission characteristics","authors":"Sylwia Berdowska, Janusz Berdowski, Aubry Frederic","doi":"10.24425/bpasts.2021.138235","DOIUrl":"https://doi.org/10.24425/bpasts.2021.138235","url":null,"abstract":". The main aim of the study was to search for the relationship between the anisotropy of the structure of polyfurfuryl alcohol (PFA) – polymer/compressed expanded graphite (CEG)-matrix composites at subsequent stages of the technological process and characteristics of the acoustic emission (AE) descriptors. These composites, obtained after successive technological procedures of impregnation, polymerization, and carbonization, possess different structure, densities, porosity, and other physicochemical properties. In the structures of composites prepared on the basis of CEG, two basic directions can be distinguished: parallel to the bedding plane of graphite sheets and perpendicular to it. The measurements were carried out for the stress acting in these two main directions. The investigation has shown that the AE method enables the detection of anisotropy in the structure of materials. The results of the research show that all four of the acoustic emission descriptors studied in this work are sensitive to the technological stages of these materials on the one hand and their structure anisotropy on the other. Fourier analysis of the recorded spectra provides interesting conclusions about the structural properties of composites as well as a lot of information about the bonding forces between the carbon atoms of which the CEG matrix is composed and the PFA polymer or turbostratic carbon.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"13 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135545603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variable order 3D models of bone remodelling","authors":"D. Valério, J. Neto, S. Vinga","doi":"10.24425/bpasts.2019.129649","DOIUrl":"https://doi.org/10.24425/bpasts.2019.129649","url":null,"abstract":". This paper presents simulations of a three-dimensional model of the bone remodelling process. The model consists of a set of variable order partial differential equations, in which the varying order depends on the presence of tumour cells. The simulations are of a two-dimensional bone, to make visualisation simpler. They show that this model corresponds to the known evolution of bone remodelling, and is simpler than integer order models found in the literature. Abstract. This paper presents simulations of a three-dimensional model of the bone remodelling process. The model consists of a set of variable order partial differential equations, in which the varying order depends on the presence of tumour cells. The simulations are of a two-dimensional bone, to make visualisation simpler. They show that this model corresponds to the known evolution of bone remodelling, and is simpler than integer order models found in the literature.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"26 32","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135545826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"148251","authors":"","doi":"10.24425/bpasts.2023.148251","DOIUrl":"https://doi.org/10.24425/bpasts.2023.148251","url":null,"abstract":"","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"94 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel source side power quality improved soft starting of three-phase induction motor using a symmetrical angle controller through pic microcontroller","authors":"S. Selvaperumal, N. Krishnamoorthy, G. Prabhakar","doi":"10.24425/bpasts.2021.136746","DOIUrl":"https://doi.org/10.24425/bpasts.2021.136746","url":null,"abstract":"© 2021 The Author(s). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Abstract. PIC microcontroller has a vital role in various types of controllers and nowadays the presence of PIC microcontroller is unavoidable in most control applications. This paper describes the enhancement of soft starting of induction motors using PIC microcontroller. Soft starting is required for the induction motors with reduced applied voltages so that the peak starting current is reduced and the startup of the motor is smooth with controlled torque and reduced mechanical vibrations, reduced starting current with correspondingly reduced bus voltage drops. While many of the available schemes of soft starting offer better results in view of smooth starting process, the proposed methodology offers soft starting as well as it cares about the source current quality. In contrast to the conventional multistep starting scheme, in this work a continuously controlled starting scheme is proposed. The three phase AC voltage controller topology is used as the core controller. In each of the half cycles, instead of a single conduction period with a single delay angle, the proposed AC voltage controller is switched symmetrically in each half cycle with multiple pulses in each quarter cycle. Symmetrically placed fixed numbers of switching pulses are used. The paper also describes the various time ratio controls namely the phase angle controller, the extinction angle controller and the symmetrical angle controller. The design aspects of the proposed soft starting scheme and the validation of the proposed system in the MATLAB SIMULINK environment are presented in this paper.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"13 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved algorithm for periodic steady-state analysis in nonlinear electromagnetic devices","authors":"T.J. Sobczyk, M. Radzik","doi":"10.24425/bpasts.2019.130878","DOIUrl":"https://doi.org/10.24425/bpasts.2019.130878","url":null,"abstract":"This paper presents the improved methodology for the direct calculation of steady-state periodic solutions for electromagnetic devices, as described by nonlinear differential equations, in the time domain. A novel differential operator is developed for periodic functions and the iterative algorithm determining periodic steady-state solutions in a selected set of time instants is identified. Its application to steady-state analysis is verified by an elementary example. The modified algorithm reduces the complexity of steady-state analysis, particularly for electromagnetic devices described by high-dimensional nonlinear differential equations.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"2 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of sectionalizing switch placement in medium voltage distribution networks in the aspect of improving the continuity of power supply","authors":"W. Bąchorek, M. Benesz","doi":"10.24425/bpasts.2020.133377","DOIUrl":"https://doi.org/10.24425/bpasts.2020.133377","url":null,"abstract":". The paper addresses the problem of placement of sectionalizing switches in medium voltage distribution networks. Proper placement of sectionalizing switches is one of the elements leading to higher power networks reliability. The methods of optimal allocation of such switches in a MV distribution network are presented in the paper. SAIDI was used as a criterion for the sectionalizing switches placement. For selecting optimum placements, three methods were used: brute force method, evolutionary algorithm and heuristic algorithm. The calculations were performed for a real MV network.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"12 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface based cohesive behavior implementation for the strength analysis of glued-in threaded rods in Glulam","authors":"T. Gečys, G. Šaučiuvėnas, L. Ustinovichius, C. Miedzialowski, P. Sulik","doi":"10.24425/bpasts.2020.134665","DOIUrl":"https://doi.org/10.24425/bpasts.2020.134665","url":null,"abstract":"The paper presents the analysis of strength and stiffness of metric threaded steel rods glued in glulam obtained by using two different gluing methods. The first method is used when the threaded steel rod is glued into a groove larger than the rod’s diameter, while the second method is applied when the diameter of the groove is smaller than the diameter of the threaded steel rod. The steel rod is covered with glue before it is inserted into the smaller diameter groove. The first method investigates the 2-mm-thick glue-line, while the second method analyses the contact when the groove’s diameter is 2 mm smaller than the outer diameter of the rod. Epoxy-type resin is used for both gluing methods. Different gluing methods present different interactions between the steel rod and glulam which result in different failure modes. The second method presents a plastic failure between the steel rod and glulam caused by the local compression and shear of glulam. The presented studies are made using metric threaded steel rods of diameters M12 and M16. In total, 20 specimens are experimentally tested in tension-to-tension tests performed according to EN 26891. The interaction between glulam and glued steel rods is also investigated using the 3D finite element modelling. The results obtained using the proposed 3D finite element model with different contact conditions between steel and glulam and the failure criterion for timber shear are well in line with the experimental findings.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"11 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135584618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}