rss_2.0Acta Mechanica et Automatica FeedSciendo RSS Feed for Acta Mechanica et Automaticahttps://sciendo.com/journal/AMAhttps://www.sciendo.comActa Mechanica et Automatica Feedhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/6470954671e4585e08aa07bc/cover-image.jpghttps://sciendo.com/journal/AMA140216Planning the Coordinate Measurements of a Freeform Surface after Milling based on a CAD Model Simulating the Surface after Machininghttps://sciendo.com/article/10.2478/ama-2024-0078<abstract><title style='display:none'>Abstract</title>
<p>This paper proposes the planning of coordinate measurements of freeform surfaces based on a model simulating the surface after machining. This model is created by the determination of a theoretical tool deflection during machining. The determined components of the simulated machining deviations are used in the reconstruction of the nominal CAD model of the surface into a model simulating the geometry of the surface after machining. This model is subdivided into areas corresponding to the assumed machining deviation intervals. This makes it possible to control the number and distribution of measuring points in separate sections of the manufactured surface. Coordinate measurements of the machined surface are made in areas where maximum deviations are expected. Here, the number and distribution of measuring points are controlled over a wide range. Coordinate measurements in other areas are carried out with significantly fewer points or may be omitted altogether. This approach makes it possible to reduce the measurement time without losing important information affecting the evaluation result. The method proposed in this paper has been tested on samples containing freeform surface. The test object was manufactured using a 3-axis milling technique with a spherical end mill.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00782024-12-31T00:00:00.000+00:00Influence of Perfluorodecalin Content on the Properties of Blood Substitutehttps://sciendo.com/article/10.2478/ama-2024-0076<abstract><title style='display:none'>Abstract</title>
<p>Blood is a vital part of our circulatory system. It is responsible for transporting oxygen and nutrients, regulating body temperature, and fighting infections. However, any imbalances in blood composition or disruptions in the blood production process can affect the body’s overall functioning. Anemia is one of the most common blood diseases diagnosed worldwide. It is characterized by a deficiency of red blood cells or hemoglobin, which reduces the body’s ability to transport oxygen. To address this issue, researchers are developing blood substitutes with artificial oxygen carriers that can replace or support the natural function of red blood cells in oxygen transport. Perfluorocarbon-based oxygen carriers (PFCs) such as perfluorodecalin (PFD) are promising for treating severe blood disorders because they can deliver O2 to tissues in various conditions. PFCs have higher storage stability than other oxygen carriers due to their bilayer sphere structure. In this study, we aimed to explore the effects of different concentrations of PFD (1%wt., 2%wt.) and storage time (7, 14, 21, 28 days) on the properties of blood substitutes, including its physicochemical (pH, surface tension, electrolytic conductivity, contact angle, redox potential, oxygen content) and rheological characteristics. The results show that the PFD concentration did not have a statistically significant effect on most of the tested properties, except for the oxygen content, which was higher for the 2%wt. solution after 28 days of incubation. The incubation time significantly impacts the change in surface tension, contact angle, redox potential, and oxygen content. The obtained results are essential due to the use of perfluorodecalin in medicine as an oxygen carrier.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00762024-12-31T00:00:00.000+00:00Determination of Heat Deflection Temperature under a Load and Vicat Softening Temperature of Powder Composites used for Ablative Shieldshttps://sciendo.com/article/10.2478/ama-2024-0077<abstract><title style='display:none'>Abstract</title>
<p>This paper presents the results of a study to determine the heat deflection temperature (HDT) and Vicat softening temperature (VST) of polymer matrix powder composites used for ablative shielding. The issue is of particular importance since, during ablative tests, the composite material is partially burnt (ablative layer). However, its remaining parts are additionally heated to a higher temperature, which is consequently associated with a change in the visco-elastic properties that depend, among other things, on the VST and HDT temperatures. In the conducted research, the authors used different mass percentages of powder modifiers (montmorillonite, halloysite, mullite, carbon nanotubes, silicon carbide) matrix base epoxy resin LH 145 Havel with the hardener H147 in the experiments. Apart from observing thermal properties that may change due to a modification of the composition of the composites, the effect of conditioning of the samples on the test results was also noticed. It is preheating a composite at a temperature as low as 55°C was observed to increase the HDT and VST by approximately 20°C and the composite hardness by approximately 3-7%.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00772024-12-31T00:00:00.000+00:00Recycled Carbon Fibers from Wind Turbine Blades: Advancing the Mechanical Performance of Concretehttps://sciendo.com/article/10.2478/ama-2024-0080<abstract><title style='display:none'>Abstract</title>
<p>Recycled carbon fibers from wind turbine blades offer a sustainable approach to enhancing concrete’s mechanical properties. This study investigates the preliminary performance of concrete reinforced with fibers recovered via pyrolysis. Experimental results demonstrate improvements in flexural strength (up to 30%) and fracture mechanics parameters (e.g., KIc and CTODc). Planned research will focus on optimizing mix designs and exploring deformation criteria for quasi-brittle materials, paving the way for environmentally friendly construction solutions.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00802024-12-31T00:00:00.000+00:00Slip Bands at the Tips of Narrow Slot in Brazilian Notched Disk – Plane Deformationhttps://sciendo.com/article/10.2478/ama-2024-0079<abstract><title style='display:none'>Abstract</title>
<p>Using the method of singular integral equations, the elastic-plastic problem for notched Brazilian disk at plane deformation state was solved. Based on Dugdale model the relationships between load, notch tip opening displacement and the length of the slip bands was established. The results demonstrate the potential of the proposed method for practical applications in engineering, particularly in the assessment of structural integrity under various loading conditions.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00792024-12-31T00:00:00.000+00:00Automation of the Oil Extraction Process Performed by Means of A Screw Presshttps://sciendo.com/article/10.2478/ama-2024-0070<abstract>
<title style='display:none'>Abstract</title>
<p>The continuous development of the oil-manufacturing industries causes the necessity of improving extraction technologies. In this case, the specific interest is focused on the control systems of screw presses. Among a great variety of such machines, the small household presses are in significant demand among consumers. Various seeds and kernels require different technological conditions to be provided in order to maximize the qualitative and quantitative characteristics of the extracted oil. Therefore, the main objective of this research is developing and testing the control system allowing for automation of the oil extraction process. Particularly, the temperature parameters of the pressing chamber, extracted oil, and electric motor are to be monitored and limited. In addition, the consumer should be able to predefine the mass of the oil to be extracted. Considering the small household screw press LiangTai LTP200, the general algorithm (block diagram) of the control system operation is proposed and the corresponding experimental prototype is developed. The latter is based on the Arduino Mega microcontroller and is equipped with three temperature sensors, two coolers (fans), one heater, and one mass sensor. The proposed control system allows for continuous monitoring and limiting of the pressing chamber, oil, and electric motor temperatures, as well as the mass of the extracted oil. The experimental data show that the pressing chamber preheating process lasts for about 3 min (170…190 s) and its maximal temperature does not exceed 44°C. The temperature of the extracted oil does not rise over 61°C. The motor temperature changes within the range of 69...71°C. The oil extraction productivity is as follows: 1.2 kg/h (sunflower seeds), 1.06 kg/h (walnut kernels), 0.9 kg/h (almond kernels), and 0.78 kg/h (peanut kernels). The obtained results can used in further investigations focused on analyzing the influence of these parameters on the quantitative and qualitative characteristics of the extracted oil.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00702024-10-30T00:00:00.000+00:00Multiphysics Simulation and Concept of an Electromagnetically Control Volumetric Pixel as a Step Towards a Shape Morphing Compositehttps://sciendo.com/article/10.2478/ama-2024-0071<abstract>
<title style='display:none'>Abstract</title>
<p>Constant development of robotics forces scientists and engineers to work on robots that are more visually and rigidly compatible with the environment around us. To make this possible, new flexible structures are necessary that enable programmatic shape change. To meet this need, in this work we present the concept and modelling methodology of a new structure enabling shape change using electromagnetic forces produced in liquid metal conductor and its stiffening using a granular jamming mechanism. This work presents the structure concept, the description of modelling methodology and empirical validation including the magnetitic field, scanned by magnetic field camera, and displacement distribution.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00712024-10-30T00:00:00.000+00:00Automatic Method of Macular Diseases Detection Using Deep CNN-GRU Network in OCT Imageshttps://sciendo.com/article/10.2478/ama-2024-0074<abstract>
<title style='display:none'>Abstract</title>
<p>The increasing development of Deep Learning mechanism allowed ones to create semi-fully or fully automated diagnosis software solutions for medical imaging diagnosis. The convolutional neural networks are widely applied for central retinal diseases classification based on OCT images. The main aim of this study is to propose a new network, Deep CNN-GRU for classification of early-stage and end-stages macular diseases as age-related macular degeneration and diabetic macular edema (DME). Three types of disorders have been taken into consideration: drusen, choroidal neovascularization (CNV), DME, alongside with normal cases. The created automatic tool was verified on the well-known Labelled Optical Coherence Tomography (OCT) dataset. For the classifier evaluation the following measures were calculated: accuracy, precision, recall, and F1 score. Based on these values, it can be stated that the use of a GRU layer directly connected to a convolutional network plays a pivotal role in improving previously achieved results. Additionally, the proposed tool was compared with the state-of-the-art of deep learning studies performed on the Labelled OCT dataset. The Deep CNN-GRU network achieved high performance, reaching up to 98.90% accuracy. The obtained results of classification performance place the tool as one of the top solutions for diagnosing retinal diseases, both early and late stage.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00742024-10-30T00:00:00.000+00:00Evaluation of Flow Resistance Increase Due to Fouling in Cooling Channels: A Case Study for Rapid Injection Moldinghttps://sciendo.com/article/10.2478/ama-2024-0067<abstract>
<title style='display:none'>Abstract</title>
<p>After certain time of operation, the cross-section of cooling channels in injection molds may decrease due to fouling, i.e. the formation and growth of a layer of sediment on the walls of the channels. This phenomenon can decrease heat transfer or ultimately completely block the flow of coolant in the channel. The build-up of the sediment layer increases the temperature of the mold, which may consequently reduce the quality of the plastic products. In the paper, the pressure drop in a typical cooling channel of an injection mold is investigated, as well as the effect of the sediment layer on the coolant flow in an example channel with a diameter of 10 mm. A novelty is the developed analytical model that allows determining the pressure drop in the case when two perpendicular channels do not intersect centrally due to manufacturing inaccuracies that often happen when drilling long channels in hard materials. The proposed hydraulic model allows for calculation of the coolant pressure drop in real injection molds and can be an alternative to time-consuming CFD simulations. The presented results of measurements and the hydraulic model calculations show that the thickness of the sediment layer in the tested channel of the actual injection mold can be up to 1.7 mm. The hydraulic model proposed in this work allows for the estimation of the thickness of the sediment layer and the identification of places of local increase in the coolant velocity, where self-cleaning of the channels in injection molds may take place.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00672024-10-30T00:00:00.000+00:00Novel Pla Composites Modified with Steel Fibres and (3-Thiopropyl) Polysilsesquioxane Derivativeshttps://sciendo.com/article/10.2478/ama-2024-0075<abstract>
<title style='display:none'>Abstract</title>
<p>In recent years, a significant increase in the development of new composite materials with desirable mechanical, thermal or surface properties has been observed. One of the popular polymers on the market is polylactide. This article explores how to modify the polymer using steel fibres and organosilicon compounds (SSQ-SH, SSQ-SH-OCT, and SSQ-SH-OFP) to enhance its properties. Test samples were obtained by injection molding with varying concentrations of 0.5%, 1%, 1.5%, 2.5%, and 5% of steel fibres. Mechanical tests, including tensile strength, elongation at break, and impact strength, were conducted, along with an analysis of the contact angle. The modified samples showed higher impact strength values, with the PLA /steel fibres /SSQ-SH sample seeing an increase of 12%. The addition of modifiers with fluoroalkyl groups led to a contact angle increase of 8.5% compared to neat PLA. Thermal tests (TGA) were also carried out to determine the influence of fibres and organosilicon compounds on decomposition.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00752024-10-30T00:00:00.000+00:00Application of Numerical Integration in Analysing the Volume of Reinforcement Particles in Algorithms for Generating Representative Volume Elements (RVEs)https://sciendo.com/article/10.2478/ama-2024-0068<abstract>
<title style='display:none'>Abstract</title>
<p>The paper focuses on spatial modelling of composites with discontinuous reinforcement. The algorithm for creating a representative volume element (RVE) must consider random distribution and size of reinforcing particles (RP), prevention of RP interpenetration, and maintaining the desired volume fraction of the reinforcing phase (Vp) in the composite microstructure. Assuming fixed RVE dimensions and randomly determined RP size, the actual Vp value needs to be continuously determined. If the assumed (desired) Vp is lower than the current value, additional reinforcement is added to the RVE. As the RP location is random, some particles may extend beyond the RVE limits, affecting Vp calculation. The research aims to determine the RP volume within the RVE boundaries when RP extends outside. The RVE was discretized with N points, and the number of Ni points within the area occupied by RP was determined. The sought value was calculated using the ratio Ni /N = Vp /VRVE, where VRVE, is the volume of the RVE. Two discretisation methods, systematised (RI) and random (Monte Carlo (MC)), were employed. The study investigated the effects of discretisation type and number N points on calculation accuracy and microstructure generation time for particle-reinforced composites in sphere, cylinder, and ellipsoid shapes. Systematised discretisation yielded higher accuracy/stability, with number N dependent on RP dimensions. The MC method reduced generation time but introduced instability and significant errors.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00682024-10-30T00:00:00.000+00:00New Prediction Of Cracks Propagation In Repaired Steel Plate With Bonded Composite Patch At Cyclic Loadinghttps://sciendo.com/article/10.2478/ama-2024-0061<abstract>
<title style='display:none'>Abstract</title>
<p>This study presents a numerical prediction of the fatigue life of steel panels repaired by a composite patch. The effect of length cracks, the stress ratio R and properties of the patch is presented. The obtained results show that the bonded composite repair significantly reduces the stress intensity factors at the tip of repaired cracks. The results are in a good agreement with those in the literature. The Monte Carlo method is used to predict the distribution function governing crack propagation in fatigue analysis. In computing the failure probability of the structure, we consider the statistical uncertainty associated with key variables, along with the previously discussed model uncertainty. The results obtained highlight the considerable impact of variations in crack length and stress ratio on the distribution function. Notably, uncertainty in these parameters significantly amplifies the probability of structural failure in plates, thereby diminishing overall structural durability.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00612024-10-30T00:00:00.000+00:00Mechanical Properties of 3D Printed PLA Scaffolds for Bone Regenerationhttps://sciendo.com/article/10.2478/ama-2024-0072<abstract>
<title style='display:none'>Abstract</title>
<p>The growing interest in biodegradable scaffolds for bone regeneration created a need to investigate new materials suitable for scaffold formation. Poly(lactic acid) (PLA) is a polymer commonly used in biomedical engineering, e.g. in tissue engineering as a biodegradable material. However, the mechanical behavior of PLA along its degradation time is still not explored well. For this reason, the mechanical properties of PLA scaffolds affected by incubation in physiological medium needs to be investigated to show the potential of PLA to be used as a material for biodegradable scaffold formation. The purpose of this research is to determine the mechanical properties of PLA scaffolds before and after incubation, and to apply constitutive material models for further behavior prediction. Two sets of PLA scaffolds were printed by the 3D printer “Prusa i3 MK3S” and sterilized by ultraviolet light and ethanol solution. The first set of specimens was incubated in DMEM (Dulbecco’s Modified Eagle Medium) for 60, 120, and 180 days maintaining 36.5 °C temperature. The mechanical properties of the scaffolds were determined after performing the compression test in the “Mecmesin MultiTest 2.5-i” testing stand with a force applied at two different speed modes. The obtained data was curve fitted with the hyperelastic material models for a model suitability study. The second set of specimens was incubated in PBS (Phosphate Buffered Saline) for 20 weeks and used in a polymer degradation study. The obtained results show that the mechanical properties of PLA scaffolds do not decrease during incubation in physiological medium for a predicted new bone tissue formation period, though hydrolysis starts at the very beginning and increases with time. PLA as a material seems to be suitable for the use in bone tissue engineering as it allows to form biocompatible and biodegradable scaffolds with high mechanical strength, required for effective tissue formation.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00722024-10-30T00:00:00.000+00:00The Construction of Analytical Exact Soliton Waves of Kuralay Equationhttps://sciendo.com/article/10.2478/ama-2024-0064<abstract>
<title style='display:none'>Abstract</title>
<p>The primary objective of this work is to examine the Kuralay equation, which is a complex integrable coupled system, in order to investigate the integrable motion of induced curves. The soliton solutions derived from the Kuralay equation are thought to be the supremacy study of numerous significant phenomena and extensive applications across a wide range of domains, including optical fibres, nonlinear optics and ferromagnetic materials. The inverse scattering transform is unable to resolve the Cauchy problem for this equation, so the analytical method is used to produce exact travelling wave solutions. The modified auxiliary equation and Sardar sub-equation approaches are used to find solitary wave solutions. As a result, singular, mixed singular, periodic, mixed trigonometric, complex combo, trigonometric, mixed hyperbolic, plane and combined bright–dark soliton solution can be obtained. The derived solutions are graphically displayed in 2-D and 3-D glances to demonstrate how the fitting values of the system parameters can be used to predict the behavioural responses to pulse propagation. This study also provides a rich platform for further investigation.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00642024-10-30T00:00:00.000+00:00Enhanced Broadband Tri-Stable Energy Harvesting System by Adapting Potential Energy – Experimental Studyhttps://sciendo.com/article/10.2478/ama-2024-0066<abstract>
<title style='display:none'>Abstract</title>
<p>This paper presents the process optimization of some key parameters, such as the size of the air gap and distance between fixed neodymium magnets to enhance the vibration-based energy harvesting effect in the tri-stable energy harvesting systems and the improved tri-stable energy harvesting system being the proposed solution under weak excitation. In order to do it, firstly the distributed parameters model of the magnetic coupling energy harvesting system, including macro fiber composites of the 8514 P2 with a homogenous material in the piezoelectric fiber layer and nonlinear magnetic force, was determined. The performed numerical analysis of the conventional and the improved tri-stable energy harvesting system indicated that introducing an additional magnet to the tri-stable system leads to the shallowing of the depth of a potential well by decreasing the air gap between magnets and consequently generating higher power output and improving the effectiveness of the proposed improved tri-stable energy harvesting system. Experiments carried out on the laboratory stand allowed us to verify the numerical results as well as determine the optimal parameters of the magnetic coupling system. Due to it, the effectiveness of the proposed system versus the conventional tri-stable energy harvesting system is most enhanced.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00662024-10-30T00:00:00.000+00:00Analytical Analysis for Space Fractional Helmholtz Equations by Using The Hybrid Efficient Approachhttps://sciendo.com/article/10.2478/ama-2024-0065<abstract>
<title style='display:none'>Abstract</title>
<p>The Helmholtz equation is an important differential equation. It has a wide range of uses in physics, including acoustics, electro-statics, optics, and quantum mechanics. In this article, a hybrid approach called the Shehu transform decomposition method (STDM) is implemented to solve space-fractional-order Helmholtz equations with initial boundary conditions. The fractional-order derivative is regarded in the Caputo sense. The solutions are provided as series, and then we use the Mittag-Leffler function to identify the exact solutions to the Helmholtz equations. The accuracy of the considered problem is examined graphically and numerically by the absolute, relative, and recurrence errors of the three problems. For different values of fractional-order derivatives, graphs are also developed. The results show that our approach can be a suitable alternative to the approximate methods that exist in the literature to solve fractional differential equations.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00652024-10-30T00:00:00.000+00:00Human Vision as A Multi-Circuit Mathematical Model of the Automated Control Systemhttps://sciendo.com/article/10.2478/ama-2024-0069<abstract>
<title style='display:none'>Abstract</title>
<p>The paper contains a proposal an original, extended mathematical model of an automatic system of human vision reaction to a forcing light pulse. A comprehensive mathematical model of the vision process was proposed in the form of an equation described in the frequency (dynamics) domain. Mathematical modelling of human senses is very important. It enables better integration of automation systems with a human cooperating with them, also as an automation system. This provides the basis for reasoning based on a mathematical model instead of intuitive reasoning about human reactions to visual stimuli. A block diagram of the proposed system with five human reaction paths is given. The following can be distinguished in the scheme: the main track consisting of: the transport delay of the eye reaction, the transport delay of the afferent nerves, the inertia of the brain with a preemptive action, the transport delay of the centrifugal nerves and the inertial and transport delay of the neuromotor system. In addition, the scheme of the system includes four tracks of negative feedback of motor and force reactions: upper eyelid, lower eyelid, pupil and lens. In the proposed model, the components of each path along with their partial mathematical models are given and discussed. For each reaction path, their overall mathematical models are also given. Taking into account the comprehensive models of all five reaction paths, a complete mathematical model of the automatic system of human reaction to a forcing light impulse is proposed. The proposed mathematical model opens up many possibilities for synchronizing it with mathematical models of many mechatronics and automation systems and their research. Optimizing the parameters of this model and its synchronization with specific models of automation systems is difficult and requires many numerical experiments. This approach enables the design of automation systems that are better synchronized with human reactions to existing stimuli and the selection of optimal parameters of their operation already in the design phase. The proposed model allows, for example, accurate determination of difficulty levels in computer games. Another example of the use of the proposed model is the study of human reactions to various situations generated virtually, for example in flight simulators and other similar ones.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00692024-10-30T00:00:00.000+00:00Research of Dynamic Processes in a Layer During Collision With an Impactorhttps://sciendo.com/article/10.2478/ama-2024-0062<abstract>
<title style='display:none'>Abstract</title>
<p>The article concerns the modeling of the transverse impact of an impactor (test sample) on the surface of an infinite elastic layer. The Laplace transform with respect to time and the Hankel transform with respect to the radius for the axisymmetric case were applied. The propagation of elastic waves in the layer and local deformations in the contact zone are taken into account. Impact force, impact time and the coefficient of restitution were examined. The results are compared with the elastic half-space. The calculations carried out showed that for layer thicknesses of more than five impactor diameters, the layer can be considered as a half-space.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00622024-10-30T00:00:00.000+00:00Determination of Static Flow Characteristics of A Prototypical Differential Valve Using Computational Fluid Dynamicshttps://sciendo.com/article/10.2478/ama-2024-0063<abstract>
<title style='display:none'>Abstract</title>
<p>The paper describes the numerical calculations of a conceptual air brake valve of a trailer equipped with a differential section, which is intended to shorten response time and braking distance. The static flow characteristics have been determined using computational fluid dynamics (CFD). Mixed (global and local) computational meshes were used in the paper to determine the static flow characteristics of the valve sections. The use of the local mesh was relevant for valve openings smaller than 0.5mm. Using CFD, it was possible to determine the static flow characteristics of the main, auxiliary feed and the differential sections, which were linear, degressive and progressive depending on the section. The analyzes, which have not yet been described in the literature, showed a significant difference in the MFR of the additional and main feed tracts, which reached 52.29%.The results are applicable to the configuration of the braking system. Further research will include performing dynamic simulations using dedicated software and building a test rig to validate the CFD calculation results.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00632024-10-30T00:00:00.000+00:00The Effect of the Molecular Weight of Hyaluronic Acid on the Rheological and Tribological Properties of the Base for Artificial Synovial Fluid Preparationshttps://sciendo.com/article/10.2478/ama-2024-0073<abstract>
<title style='display:none'>Abstract</title>
<p>The synovial fluid is responsible for adequately lubricating, moisturizing, and nutritional human joints. This liquid should have appropriate viscoelastic properties and ensure a low coefficient of friction in biotribological systems. Many artificial synovial fluid preparations used in viscosupplementation treatments are based on hyaluronic acid. This work aimed to evaluate the influence of molecular weight on the functional properties of solutions based on hyaluronic acid. 1% solutions based on hyaluronic acid with five different molecular weights from 50,000 Da to 2 MDa were made. Rheological (viscosity, viscoelasticity), tribological (coefficient of friction, wear assessment), and wettability tests were carried out. Significant differences were observed in the rheological tests, where the viscosity strictly depends on the molecular weight of the hyaluronic acid. It has been shown that the molecular weight of HA has little effect on the coefficient of friction. On the other hand, the differences in the tribological wear are much more significant. The molecular weight of biopolymers is one of the essential parameters in developing new artificial synovial fluids. Using a higher molecular weight of hyaluronic acid increases viscosity and wettability, resulting in less tribological wear.</p>
</abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/ama-2024-00732024-10-30T00:00:00.000+00:00en-us-1