TY - JOUR AU - Kulcsár, Klaudia AU - Zsoldos, Ibolya TI - Mechanical Studies of Subperiosteal Implants JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 2024 PY - 2024 SN - 0324-6051 DO - 10.3311/PPme.23706 UR - https://m2.mtmt.hu/api/publication/34535659 ID - 34535659 AB - When designing subperiosteal implants, mechanical testing of the implant and abutment is inevitable. Subperiosteal implants and their abutments are medical devices made to order, so each implant requires a separate design, since each patient has a different bone surface, for which the implant must be designed. For the mechanical testing of subperiosteal implants, a new test apparatus was constructed, on which mechanical simulations were carried out, the subperiosteal implants were tested together with their abutments. In addition to the finite element analysis simulation, the test apparatus can also be used to determine how much force is generated by the chewing force on the subperiosteal implant and its abutment as a result of the chewing mechanism. LA - English DB - MTMT ER - TY - JOUR AU - Garbai, László AU - Sánta, Róbert AU - Zónai, Viktor TI - Assessment of Simultaneous Heating Demands for Consumer Groups JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 211 EP - 215 PG - 5 SN - 0324-6051 DO - 10.3311/PPme.36546 UR - https://m2.mtmt.hu/api/publication/35182272 ID - 35182272 N1 - Department of Building Services and Process Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary Aziz Sanjar Food Safety Laboratory, Azerbaijan State University of Economics (UNEC), 6, Istiglaliyyat str., Baku, AZ1001, Azerbaijan Institute of Engineering Sciences, University of Dunaújváros, Táncsics Mihály 1/A, Dunaújváros, H-2400, Hungary Department of Security Sciences, OE Security Sciences Doctoral School, University of Óbuda, Népszínház u. 8, Budapest, H-1071, Hungary Export Date: 04 September 2024; Cited By: 0; Correspondence Address: R. Sánta; Aziz Sanjar Food Safety Laboratory, Azerbaijan State University of Economics (UNEC), Baku, 6, Istiglaliyyat str., AZ1001, Azerbaijan; email: santar@uniduna.hu; CODEN: PPMMB AB - The paper presents the determination of the simultaneity factor in district heating systems based on the simultaneous heat demand level of a group of consumers. The simultaneity factor is formed on a probability theory basis, involving a prescribed risk. The simultaneity factor is a ratio that indicates the proportion of the aggregated nominal heat demand of consumers that occurs at a specific time. As known, the simultaneity factor is less than one. Knowledge of the simultaneity factor allows us to uncover performance reserve capacity in a district heating system. This way, there are often opportunities for expanding district heating systems, connecting new consumers, and improving the economic efficiency of operation. LA - English DB - MTMT ER - TY - JOUR AU - Ficzere, Péter TI - Surface Anisotropy on 3D Printed Parts JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 272 EP - 277 PG - 6 SN - 0324-6051 DO - 10.3311/PPme.37770 UR - https://m2.mtmt.hu/api/publication/35168895 ID - 35168895 N1 - Export Date: 9 September 2024 CODEN: PPMMB Correspondence Address: Ficzere, P.; Department of Railway Vehicles and Vehicle System Analysis, Műegyetem rkp. 3, Hungary; email: ficzere.peter@kjk.bme.hu AB - It is well known that the surface quality obtained in additive manufacturing processes is highly variable. There are several reasons for this, of which the most prominent is the staircase effect, which results from the fact that 3D printing can be actually considered as a 2.5 machining process, as we build the part layer by layer. However, this staircase effect can be very different on surfaces that are arranged in different ways. By measuring the values that characterise the surfaces (Ra, a , Rz), z ), however, we can observe that they are direction dependent, i.e. it does not matter how we measure them. This phenomenon is called surface anisotropy. It is clear that the surface roughness also has an effect on the tribological behaviour. In the case of a component where it is in contact with another component and relative displacement occurs between them, frictional properties may play a prominent role, which may thus also become direction dependent. Surface roughness also has a clear effect on fatigue properties. Consequently, for parts undergoing periodic dynamic stresses, it may be important to choose the right manufacturing orientation. The present study aims to demonstrate the extent of variation in surface roughness on different surfaces of a part produced by FDM. For this purpose, surface quality factors are investigated and evaluated on a self-designed model produced with given manufacturing parameters. LA - English DB - MTMT ER - TY - JOUR AU - Friedrich, Péter AU - Paál, György TI - Can the Flow Simulation Domain for Bifurcation Aneurysms on the Willis Circle Be Radically Reduced? JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 216 EP - 224 PG - 9 SN - 0324-6051 DO - 10.3311/PPme.37086 UR - https://m2.mtmt.hu/api/publication/35162474 ID - 35162474 N1 - Funding Agency and Grant Number: Gedeon Richter Talentum Foundation Funding text: Peter Friedrich and his work were supported by the Gedeon Richter Talentum Foundation in the framework of the Gedeon Richter Excellence PhD Scholarship. AB - This paper presents an attempt to decrease the domain for the simulation of blood flow in certain types of bifurcation aneurysms. A reduced computational cost would be beneficial for the simulation of large datasets, to have statistical data for various hemodynamical parameters. The reduction is achieved by cutting the geometry in an objective manner, with the help of the Vascular Modelling Toolkit (VMTK). CFD simulations were carried out on both the original and the partial geometries, using partially patient-specific boundary conditions. The post-processing focused on the velocity field, as it is more robust than the wall shear stress-based indicators for aneurysm formation. Using VMTK, a centerline was calculated for each case. Various morphological values can be calculated, namely the torsion and curvature. The velocity field was broken down to velocity components using the Frenet-frames. The evaluation was carried out on a plane before the next bifurcation downstream. The post-processing calculations were made for 2 distinct time steps, one at the systolic and one at the diastolic instant and for a cycle average. The results showed that the method reproduces the axial velocity component with small deviations. However, for the secondary components the difference between the partial and original geometries was unacceptably high. Therefore, the method proved to be unsuitable. LA - English DB - MTMT ER - TY - JOUR AU - Horváth, Dániel AU - Poós, Tibor TI - New Dimensionless Power Number Equation for Horizontal Agitated Drum JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 234 EP - 246 PG - 13 SN - 0324-6051 DO - 10.3311/PPme.37286 UR - https://m2.mtmt.hu/api/publication/35153036 ID - 35153036 N1 - Funding Agency and Grant Number: Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences [BO/00059/23/6]; Hungarian Scientific Research Fund [NKFIH FK-142204]; Gedeon Richter's Talentum Foundation, Budapest, Hungary; New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund [NKP-23-5-BME-411] Funding text: This work was supported by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences (BO/00059/23/6) and by the Hungarian Scientific Research Fund (NKFIH FK-142204) . The first author was supported by Gedeon Richter's Talentum Foundation (H-1103 Budapest, Gyoemr & odblac;i str. 19-21, Hungary) . The second author was supported by the & Uacute;NKP-23-5-BME-411 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund. AB - In dryers where mechanical mixing is applied, it is necessary to know the motor power requirement in order to design the dryer correctly. The power requirement of the motor can be traced back to the no-load power requirement and the mixing power requirement. In this study, a new dimensionless power number equation has been introduced to determine the mixing power requirement of horizontal agitated drums. A simplified form of the dimensionless power equation for the investigated agitated drum and granular material was created. The equation took into account the effect of the mixing Froude number. The values of the equation’s unknown parameters were determined by a nonlinear solver using laboratory measurements. A new dimensionless number was introduced which contains the mixing power requirement and was named cohesive power number. This dimensionless number determines the relationship between the mixing power requirement and the bulk cohesion by taking into account the typical size of the mixer and the rotational speed. LA - English DB - MTMT ER - TY - JOUR AU - Gao, Min AU - Telles Salgueiro Barboni, Mirella AU - Szabó, Viktória AU - Nagy, Zoltán Zsolt AU - Zobor, Annamária Ditta AU - Nagy, Balázs Vince TI - Oscillatory Potential-based Characterization of the Human Light-adapted Electroretinogram Using Discrete Wavelet Transform JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 187 EP - 195 PG - 9 SN - 0324-6051 DO - 10.3311/PPme.23845 UR - https://m2.mtmt.hu/api/publication/35145278 ID - 35145278 N1 - Department of Mechatronics, Optics and Mechanical Engineering Informatics, Facalty of Machanical Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3, Budapest, H-1111, Hungary Department of Ophthalmology, Facalty of Health science, Semmelweis University, Vas utca 17, Budapest, H-1088, Hungary Export Date: 9 September 2024 CODEN: PPMMB Correspondence Address: Nagy, B.V.; Department of Mechatronics, Műegyetem rkp. 3, Hungary; email: nagyb@mogi.bme.hu Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: TKP2021-EGA-02 Funding details: 134799 Funding details: Tempus Közalapítvány, TPF, 167949 Funding details: China Scholarship Council, CSC, 202002890007 Funding text 1: BME-NVA-02, implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development, and Innovation Fund, financed under the TKP2021 funding scheme. This research was funded by the National Research, Development, and Innovation Fund of Hungary under Grant TKP2021-EGA-02. The research was supported by Stipendium Hungaricum Scholarship of Tempus Public Foundation, and China Scholarship Council (202002890007) to GM. Research supported by National Research, Development, and Innovation Fund of Hungary to MTSB (OTKA-PD grant number 134799) and the Tempus Public Foundation (Hungary) to MTSB (TKA grant number 167949). AB - Purpose: Our aim was to apply multiple discrete wavelet transformation (DWT) types to healthy light-adapted (cone) electroretinogram (ERG) signals in order to optimize DWT analysy in ERG. Oscillatory potentials (OP) were individually extracted from the signals and used to calculate an indicator for ERG analysis. Methods: Light-adapted (LA) 3.0 cd.s/m(2) ISCEV standard ERGs were recorded from both eyes of 15 healthy volunteers (mean age: 36.9 +/- 13.0 years old; 13 females). LA ERG signal components, such as b-wave and OPs, were analyzed using the discrete wavelet transformation (DWT). An index (%OPi) was proposed to estimate the individual oscillatory potentials (OP1-OP5) by calculating the coefficient ratio of the OP to b-wave. Multiple mother wavelet functions (i.e., Daubechies, Symlet, and Coiflet) with five orders were applied and compared statistically using Wilcoxon tests and paired t-test comparisons with Bonferroni posthoc analyses (p < 0.005). Results: OP4 shows the most energy at both low and high-frequency bands (80Hz and 160Hz), while OP2 has lower energy at the lowfrequency band (80Hz) and higher energy at the high-frequency band (160Hz). The %OP2 is the largest among the five individual OPs. %OPs obtained with different wavelet functions differ from each other. Db2 and sym2 seem to be the optimal wavelets for analyzing light-adapted ERG components. Conclusion: Individual OPs of the light-adapted ERG obtained with the DWT analysis may characterize different levels of retinal dysfunction. The %OPi may serve as an indicator in ERG analysis. LA - English DB - MTMT ER - TY - JOUR AU - Kun, Krisztián AU - Bata, Attila AU - Ronkay, Ferenc György TI - Investigation of the Replication Quality of Microstructures on Injection Moulded Specimens Made from Recycled Polypropylene Composites Reinforced with Carbon Nanotubes JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 247 EP - 253 PG - 7 SN - 0324-6051 DO - 10.3311/PPme.37288 UR - https://m2.mtmt.hu/api/publication/35141338 ID - 35141338 AB - During the research, functional microstructures were created on the cavity surface of the injection moulding tool using femtosecond laser technology. Automotive-grade polypropylene (PP), as well as its recycled and carbon nanotube-reinforced composites, were used as the raw materials. The replicated structures were examined using confocal microscopy. It is expected that by optimizing the process parameters, the filling of the structured cavity surface with nanocomposite materials can reach a quality level comparable to plastic specimens made from non-reinforced raw materials. The aim is to provide results of scientific and industrial value to demonstrate the influence of the modified mould surface on the flow of the polymer melt and thus on the filling of the injection moulded products. LA - English DB - MTMT ER - TY - JOUR AU - Ágoston, Dorottya AU - Bozori, Gabriella AU - Kiss, Rita TI - Investigating the Effectiveness of Equine-assisted Therapy on Children Regardless of Their Mental Disorder JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 264 EP - 271 PG - 8 SN - 0324-6051 DO - 10.3311/PPme.37390 UR - https://m2.mtmt.hu/api/publication/35055828 ID - 35055828 N1 - Funding Agency and Grant Number: Hungarian Scientific Research Fund (OTKA) [K146308.] Funding text: The work was funded by the Hungarian Scientific Research Fund (OTKA) , Kepponttol az elemzesig: markermentes sportteljesitmeny a palyan, grant number: K146308. AB - Equine-assisted therapy (EAT) is a common and popular complementary and alternative therapy among children with different mental disorders. In this study, the effectiveness of EAT was investigated on children with diverse mental disorders by analyzing their gait. Fifty-six children (age: 8.30 ± 3.77 years) were involved in the research who participated weekly in equine-assisted therapy during a school year. The gait of the children was measured twice with the GAITRite® pressure-sensing mat, before and after the therapy period. The participants did ten sections of walking on the pressure-sensing mat. Twenty-one spatial and temporal gait parameters were chosen and evaluated for further statistical analysis. To determine the normal distribution of the parameters, the Lilliefors normality test was carried out. Depending on the result, the paired t test or the Wilcoxon signed-rank test was used to compare the means of the results of the two measurements (p < 0.05). Significant differences were observed for eight out of the twenty-one parameters which investigation provides some promising results regarding the benefits of equine-assisted therapy for children's quality of life. LA - English DB - MTMT ER - TY - JOUR AU - Németh, Márton Bence AU - Csippa, Benjamin AU - Mihály, Zsuzsanna AU - Paál, György AU - Sótonyi, Péter TI - Boundary Condition Options for Carotid Bifurcation Analysis, Using Doppler Velocity Measurements JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 196 EP - 210 PG - 15 SN - 0324-6051 DO - 10.3311/PPme.28797 UR - https://m2.mtmt.hu/api/publication/34986699 ID - 34986699 N1 - Department of Hydrodynamic Systems, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest, H-1111, Hungary Department of Vascular and Endovascular Surgery, Semmelweis University Budapest, Városmajor str. 68, Budapest, 1122, Hungary Export Date: 9 September 2024 CODEN: PPMMB Correspondence Address: Németh, M.B.; Department of Hydrodynamic Systems, Műegyetem rkp. 3., Hungary; email: mnemeth@hds.bme.hu Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, TKP-9-8/PALY-2021, NKFIH-K 129277, NKFI-PD 146299 Funding text 1: This study was supported by the National Research, Development and Innovation Office. under Grant number NKFIH-K 129277 and NKFI-PD 146299. Project no. TKP-9-8/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-EGA funding scheme. AB - The Common Carotid Artery plays a vital role in supplying the brain, and its bifurcation is susceptible to vascular diseases. It is often analyzed using computational fluid dynamics (CFD) simulations, but it is challenging to prescribe boundary conditions that approach patient-specific flow conditions. We examined six boundary condition (BC) groups to determine the most accurate flow conditions aligning with available measured data. We conducted CFD simulations on a stenotic carotid bifurcation, using patient-specific Doppler ultrasound sonography velocity measurements at the inlet and both outlets. Three BC methods used defined inlet flow rate and either constant pressure (Basic), Windkessel model, or constant flow ratio (Murray) at the outlets. Three other methods were defined with flow rates at two boundaries and constant pressure at the third one. Defining two boundary flow rates shows the closest results to physiologically valid data. However, the difficult Doppler measurements on the outlet branches can inaccurately amplify velocity amplitudes and may detect a false flow direction. Therefore, cross-sectional corrections were implemented to fit the outlet and inlet flow rates, while keeping the measured velocity histories.Our results show that the Murray and Basic methods, while easily available, exclude carotid-specific flow conditions by disregarding downstream flow resistances. We conclude that a Windkessel-method can produce the most accurate results without forcing outflow conditions. However, usually unavailable measurements are necessary for its application. Simulations with outlet-defined volume flow can also produce physiologically valid solutions but require the application of cross-sectional geometry correction. LA - English DB - MTMT ER - TY - JOUR AU - Abu Taleb Al-Awamleh, Ahmad AU - Hegedűs, Ferenc TI - Sono-hydrogen: a theoretical investigation of its energy intensity JF - PERIODICA POLYTECHNICA-MECHANICAL ENGINEERING J2 - PERIOD POLYTECH MECH ENG VL - 68 PY - 2024 IS - 3 SP - 254 EP - 263 PG - 10 SN - 0324-6051 DO - 10.3311/PPme.37299 UR - https://m2.mtmt.hu/api/publication/34883914 ID - 34883914 N1 - Funding Agency and Grant Number: Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund [TKP-6-6/PALY-2021]; NVIDIA Corporation via the Academic Hardware Grants Program; Hungarian National Research, Development and Innovation Office via NKFIH grant [OTKA FK142376] Funding text: Project no. TKP-6-6/PALY-2021 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA fund- ing scheme. This paper was also supported by the NVIDIA Corporation via the Academic Hardware Grants Program. The authors acknowledge the financial support of the Hungarian National Research, Development and Innovation Office via NKFIH grant OTKA FK142376. LA - English DB - MTMT ER -