I. Zsoldos

56031632000

Publications - 43

Experimental Investigation on the Erosion Resistance Characteristics of Compressor Impeller Coatings to Water Droplet Impact

Csaba Tóth-Nagy István Barabás I. Zsoldos Pavel Novotny Richárd Takács Izolda Popa-Müller Balázs Dobos Miklós Zsolt Tabakov Norbert Kiss

Publication Name: Coatings

Publication Date: 2025-07-01

Volume: 15

Issue: 7

Page Range: Unknown

Description:

This study presents a comparative analysis of the water droplet erosion resistance of three compressor wheels coated with Ni-P and Si-P layers. The tests were conducted using a custom-developed experimental apparatus in accordance with the ASTM G73-10 standard. The degree of erosion was monitored through continuous precision mass measurements, and structural changes on the surfaces of both the base materials and the coatings were examined using a Zeiss Crossbeam 350 scanning electron microscope (SEM). Hardness values were determined using a Vickers KB 30 hardness tester, while the chemical composition was analysed using a WAS Foundry Master optical emission spectrometer. Significant differences in erosion resistance were observed among the various compressor wheels, which can be attributed to differences in coating hardness values, as well as to the detachment of the Ni-P layer from the base material under continuous erosion. In all cases, water droplet erosion led to a reduction in the isentropic efficiency of the compressor—measured using a hot gas turbocharger testbench—with the extent of efficiency loss depending upon the type of coating applied. Although blade protection technologies for turbocharger compressor impellers used in the automotive industry have been the subject of only a limited number of studies, modern technologies, such as the application of certain alternative fuels and exhaust gas recirculation, have increased water droplet formation, thereby accelerating the erosion rate of the impeller. The aim of this study is to evaluate the resistance of three different coating layers to water droplet erosion through standardized tests conducted using a custom-designed experimental apparatus.

Open Access: Yes

DOI: 10.3390/coatings15070767

Water Droplet Collison and Erosion on High-Speed Spinning Wheels

I. Zsoldos Richárd Takács Dániel Szentendrei

Publication Name: SAE International Journal of Engines

Publication Date: 2024-04-04

Volume: 17

Issue: 5

Page Range: Unknown

Description:

The water droplet erosion (WDE) on high-speed rotating wheels appears in several engineering fields such as wind turbines, stationary steam turbines, fuel cell turbines, and turbochargers. The main reasons for this phenomenon are the high relative velocity difference between the colliding particles and the rotor, as well as the presence of inadequate material structure and surface parameters. One of the latest challenges in this area is the compressor wheels used in turbochargers, which has a speed up to 300,000 rpm and have typically been made of aluminum alloy for decades, to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage. One such fluid is the condensed water in the low-pressure exhaust gas recirculation channel (LP-EGR) formulated at cold starts and low-speed high load conditions. This kind of design has been developed to reduce nitrogen oxide emissions and is used in both gasoline and diesel engines. This article presents a state-of-the-art review of this WDE process, focusing on the formation of the condensed water before the compressor wheel, summarizing the influencing factors of WDE and the effects of the damage including using component testbench experiences and simulation methodologies. Inspection possibilities such as high-speed camera measurement and vibration analysis are also an important part of the document.

Open Access: Yes

DOI: 10.4271/03-17-05-0037

Water-Insoluble, Thermostable, Crosslinked Gelatin Matrix for Soft Tissue Implant Development

István Hornyák I. Zsoldos Sara Cruciani Róbert Várdai B. Kocsis Renzo Pala Viktória Varga László Smeller

Publication Name: International Journal of Molecular Sciences

Publication Date: 2024-04-02

Volume: 25

Issue: 8

Page Range: Unknown

Description:

In this present study, the material science background of crosslinked gelatin (GEL) was investigated. The aim was to assess the optimal reaction parameters for the production of a water-insoluble crosslinked gelatin matrix suitable for heat sterilization. Matrices were subjected to enzymatic degradation assessments, and their ability to withstand heat sterilization was evaluated. The impact of different crosslinkers on matrix properties was analyzed. It was found that matrices crosslinked with butanediol diglycidyl ether (BDDE) and poly(ethylene glycol) diglycidyl ether (PEGDE) were resistant to enzymatic degradation and heat sterilization. Additionally, at 1 v/v % crosslinker concentration, the crosslinked weight was lower than the starting weight, suggesting simultaneous degradation and crosslinking. The crosslinked weight and swelling ratio were optimal in the case of the matrices that were crosslinked with 3% and 5% v/v BDDE and PEGDE. FTIR analysis confirmed crosslinking, and the reduction of free primary amino groups indicated effective crosslinking even at a 1% v/v crosslinker concentration. Moreover, stress–strain and compression characteristics of the 5% v/v BDDE crosslinked matrix were comparable to native gelatin. Based on material science measurements, the crosslinked matrices may be promising candidates for scaffold development, including properties such as resistance to enzymatic degradation and heat sterilization.

Open Access: Yes

DOI: 10.3390/ijms25084336

Particle Number Concentration and SEM-EDX Analyses of an Auxiliary Heating Device in Operation with Different Fossil and Renewable Fuel

I. Zsoldos György Szabados Péter Nagy I. Szabó

Publication Name: Inventions

Publication Date: 2024-02-01

Volume: 9

Issue: 1

Page Range: Unknown

Description:

Pollution from road vehicles enters the air environment from many sources. One such source could be if the vehicle is equipped with an auxiliary heater. They can be classified according to whether they work with diesel or gasoline and whether they heat water or air. The subject of our research series is an additional heating system that heats the air, the original fuel is gasoline. This device has been built up in a modern engine test bench, where the environmental parameters can be controlled. The length of the test cycle was chosen to be 30 min. The tested fuels were E10, E30, E100 and B7. A 30-min operating period has been chosen in the NORMAL operating mode of the device as a test cycle. The focus of the tests was particle number concentration and soot composition. The results of the particle number concentration showed that renewable fuel content significantly reduces the number concentration of the emitted particles (9.56 × 108 #/cycle for E10 vs. 1.65 × 108 #/cycle for E100), while B7 causes a significantly higher number of emissions than E10 (3.92 × 1010 #/cycle for B7). Based on the elemental analysis, most deposits are elemental carbon, but non-organic compounds are also present. Carbon (92.18 m/m% for E10), oxygen (6.34 m/m% for E10), fluorine (0.64 m/m% for E10), and zinc (0.56 m/m% for E10) have been found in the largest quantity of deposits taken form the combustion chamber.

Open Access: Yes

DOI: 10.3390/inventions9010013

CT-Based Defect Analysis in Aluminium Rotor End Rings †

I. Zsoldos I. Kozma

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

The advantages of using cast aluminium rotors have been proven recently. However, discontinuities and porosities created during the casting of aluminium can cause problems during motor operation, such as eccentricity, losses, unwanted sounds, and false rotor fault indications. During the casting technology, care must be taken to ensure that there are as few cracks and porosities as possible in the volume and that their distribution is homogeneous. In this article, we present in detail the application of the modern CT-based methodology that has been spreading recently for the detection and analysis of discontinuities, voids, and porosities created during the casting of rotor end rings.

Open Access: Yes

DOI: 10.3390/engproc2024079093

Mechanical Studies of Subperiosteal Implants

I. Zsoldos K. Kulcsár

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2024-01-01

Volume: 68

Issue: 1

Page Range: 53-62

Description:

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.

Open Access: Yes

DOI: 10.3311/PPme.23706

Heat Characteristics and Emission Effect of a Fuel-operated Auxiliary Air Heater Fed with Fuel E10, E30 and E100

I. Zsoldos György Szabados Péter Nagy

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2024-01-01

Volume: 68

Issue: 2

Page Range: 181-186

Description:

In order to increase the comfort of vehicle passengers in specific vehicle categories, the heating of the passenger compartment is not provided by the heat from the engine driving the vehicle but by an additional heating device. The study examines the effect of auxiliary heaters that use liquid fuels to heat the passenger compartment of vehicles. The device was operated during the test with two different mixtures containing bioethanol (E30, E100) and the original motor gasoline (E10). It aimed to understand the effects of different fuels, particularly heating performance, operating time and emissions. Based on the results, as the ethanol content increases, the temperature of the device’s flame and heating air decreases. The experiments showed that in the case of E100 bioethanol, the average temperature measured in stable operating conditions was significantly lower than in the case of E10 motor gasoline. That suggests that an increase in the ethanol content reduces the heating performance. Another significant result of the study was that in the case of mixtures containing ethanol, a longer operating time is required to achieve the same amount of heat, which leads to additional fuel consumption. In addition, when using E100 bioethanol, the amount of harmful gases that are emitted increases significantly during the longer operating time. This observation can be important for evaluating the environmental impact and efficiency of vehicles.

Open Access: Yes

DOI: 10.3311/PPme.36911

Mechanical Fatigue Test of Individual Dental Implants

I. Zsoldos Ádám Vörös Klaudia Kulcsár Talabérné

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 501-508

Description:

Since subperiosteal dental implants are custom made implants, design and manufacturing must be carried out with great care, solving comprehensive mechanical analyses. In this work, we performed a 3-day fatigue test on a 3D-printed titanium implant in a custom-designed mechanical testing device. After three days of average chewing loading, no residual deformation was observed. Moreover, no cracks or inclusions were observed when examining the CT scans. Nor did the printing defects on the implant cause any problems. The tested implant showed satisfactory results and was considered to be suitable for implantation. With the case study, we also showed that the new experimental methodology developed for the mechanical examination of subperiosteal implants is suitable for fatigue examinations of implants.

Open Access: Yes

DOI: 10.3233/ATDE240586

Examination of the Emission of Gas-Phase Components, Including Some Not-Conventional Ones from a Parking Heater, While Increasing the Bioethanol Content of the Fuel

I. Zsoldos György Szabados Péter Nagy

Publication Name: Energies

Publication Date: 2023-06-01

Volume: 16

Issue: 12

Page Range: Unknown

Description:

The air pollutant emissions of a motor vehicle do not only mean the emissions from the engine used for propelling the vehicle. Another possible source is the passenger compartment heater. In the focus of our research, we investigated the effect of mixing gasoline-powered cabin air and ethanol (E10, E30, E100 on a volumetric basis) on the emissions of the equipment. Among the pollutant components examined, there were conventional components and so called not-conventional components. The chosen length of the test was 1800 s, while the intake air parameters temperature (tin) and relative humidity (h) have been kept constant (tin = 15 °C, h = 30%). Bioethanol mixing has a significant reducing effect on NOx (oxides of nitrogen) and CO2 (carbon dioxide). As for the components CO (carbon monoxide), THC (total hydrocarbons), CH4 (methane) and N2O (nitrous oxide), the values of the components reach usable values only in the start-up and burnout phases, while in the stable-operation phase, their values are outside the limit of detectability. A small part of THC is only CH4; a more significant part is NMHC (non-methane hydrocarbons). The results of the developed vehicle fleet model for calculating the GHG (greenhouse gas) emissions of a vehicle fleet equipped with such a device showed that the fleet’s GHG emissions are less than 1% of the annual emissions from the combustion of transport fuel.

Open Access: Yes

DOI: 10.3390/en16124786

Comparing the Combustion Process and the Emission Characteristic of a Stationary Heating Device System and an Internal Combustion Engine with Experimental Investigation

I. Zsoldos György Szabados Péter Nagy Jan Rohde-Brandenburger

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2023-01-01

Volume: 51

Issue: 1

Page Range: 96-104

Description:

Stationary heating devices can be used to warm up the coolant of an internal combustion engine or the cabin air of a vehicle. This kind of heat engine transforms the chemical energy content of liquid fuels into heat energy. The combustion process and the emission of such a device is in focus in this study, which would be the first part in a greater project in the field. Therefore, some relevant parameters have been established. Relevant cycles have been chosen for the kinds of heat engines. It means a normal mode cycle for the stationary device and a WLTC cycle in the case of the direct injection gasoline engine. Fuel used was the same for both. This heat transfer process is such, that the combustion seems to be quite simple and rough in the stationary device compared to that of in internal combustion engine. This means an inhomogenous combustion with non-premixed flame at a low combustion temperature. This situation affects the emission characteristic accordingly, so causes low NOx and relatively high particle relevant emission comes out from the device. As far as the device's particle relevant emission is concerned it would be suitable for further investigation described at the end of the article.

Open Access: Yes

DOI: 10.3311/PPtr.18751

Investigation of Turbocharger Compressor Wheel Damage Due to Collision with Condensed Water Droplets

I. Zsoldos András Lajos Nagy Richárd Takács

Publication Name: Lecture Notes in Mechanical Engineering

Publication Date: 2023-01-01

Volume: Unknown

Issue: Unknown

Page Range: 575-581

Description:

The compressor wheels used in turbochargers have typically been made of aluminium alloy for decades. The primary reason is to achieve the lowest possible rotor inertia. However, while in the past this component was only encountered with filtered air, nowadays, due to developments in compliance with tightening emission standards, various fluids also collide with the spinning blades, which can cause mechanical damage. One such fluid is condensed water in the low-pressure exhaust gas channel (LP-EGR) formulated at cold starts and low-load conditions. This kind of design has been developed to reduce the nitrogen oxide emission and is used in both Otto and Diesel engines. This paper presents a testing method - implemented on a component testbench - and its results for this phenomenon. First, the effect of the volume flow of the condensed water colliding with the spinning blades was analyzed, and then, in addition to a constant volume flow, the speed dependence of the degree of damage was also determined. Next to the visual inspections, the physical changes on the blades were also detected by vibration diagnostic tools, mainly by analyzing the amplitude of the order correlated to the number of blades, from which we can deduce the changed balance level of the rotor.

Open Access: Yes

DOI: 10.1007/978-3-031-15211-5_48

Optimal microstructure and mechanical properties of open-cell porous titanium structures produced by selective laser melting

Matej Buzgo Pedro Ferreira Costa I. Zsoldos K. Kulcsár

Publication Name: Frontiers in Bioengineering and Biotechnology

Publication Date: 2022-10-04

Volume: 10

Issue: Unknown

Page Range: Unknown

Description:

Three-dimensional printing technology enables the production of open cell porous structures. This has advantages but not only in terms of weight reduction. In implant structures, the process of osseointegration is improved, mechanical integration is better, the open cell porous structures resemble a trabecular structure that mimics bone tissue. In this work, we investigated titanium structures made porous by cutting spheres. Based on the patterns of different types of crystal models we created porosity with different strategies. We have shown that there are significant differences in mechanical properties between the porous structures formed with different strategies. We determined the structure that loses the least load-bearing capacity compared to the solid structure, with the same porosity levels and mechanical stresses. We characterized the possibility location and environment of becoming an open cell structure. We performed the calculations with mechanical simulations, which were validated experimentally. The quality of the three-dimensional printing of samples was checked by computed tomography reconstruction analysis.

Open Access: Yes

DOI: 10.3389/fbioe.2022.1022310

Wear behaviour of ceramic particle reinforced atmospheric plasma spray coatings on the cylinder running surface of internal combustion engines

I. Zsoldos Alexander Dudas András Lajos Nagy Gabor Laki Barna Hanula Dirk Bartel

Publication Name: Wear

Publication Date: 2022-08-15

Volume: 502-503

Issue: Unknown

Page Range: Unknown

Description:

Atmospheric plasma spray coatings can provide a solution for corrosion and wear resistant cylinder coating surfaces in hybrid powertrains. This article presents experimental results from a model study of metal matrix composite coating samples of chromium steel with varied ceramic content, in order to characterize the effect of hard particles and porous coating structure on friction and wear. Experiments were conducted on a high-frequency reciprocating rig with coated cast-iron cylinder segments and hard chromium coated piston ring segments. Samples were investigated under continuous and scarce lubrication conditions. A ceramic content of 35 wt% was found to be ideal in terms of friction and wear. Coatings with a higher ceramic content exhibited severe abrasive wear, whereas a ceramic content under 35 wt% allowed for increased adhesion between the ring and cylinder surfaces. A detailed investigation of focused ion beam milled sections of the coated cylinder wall segments revealed a stabilizing effect of the ceramic particles, which reduces the delamination of the coating structure.

Open Access: Yes

DOI: 10.1016/j.wear.2022.204373

Artificial aging experiments of neat and contaminated engine oil samples

I. Zsoldos András Lajos Nagy Jan Rohde-Brandenburger

Publication Name: Lubricants

Publication Date: 2021-06-01

Volume: 9

Issue: 6

Page Range: Unknown

Description:

This study highlights how the results from an artificial engine oil aging method compare to used engine oil samples collected from a vehicle fleet. Additionally, this paper presents the effect of contaminating the oil during aging with synthetic fuel alternatives on the physical and chemical properties of artificially aged engine oil samples. A laboratory-scale artificial thermo-oxidative aging experiment was conducted on multiple samples of commercially available formulated fully-synthetic SAE 0W-30 engine oil. The goal of the experiment was to establish the validity of the artificially aged samples as well as the validity of the underlying process in reproducibly fabricating small batches of aged engine oil with comparable chemical and physical properties to real-life used oils. Eight samples were subjected to distinct load cases (temperature, air flow rate, sample volume and aging time). Six additional samples were subjected to an intermediate load case, with five of them contaminated with selected conventional fuels and novel automotive fuel candidates. Conventional oil analysis was conducted on each sample to determine oxidation, residual additive content, kinematic viscosity and total base number. Additionally, analysis results were compared to in-use engine oil samples through PCA. The resulting oil condition after aging is in accordance with independently published results in terms of zinc dialkyldithiophosphate content and kinematic viscosity. Contaminated aging with OME3-5 resulted in a drop in antioxidant content and elevated kinematic viscosity. Based on the comparison with in-use samples, artificial aging of 200 mL engine oil at 180◦ C with 1 L/min air flow for 96 h can produce similar oil conditions as mixed vehicle use for 7000 km.

Open Access: Yes

DOI: 10.3390/lubricants9060063

A Review on the Differences Between Particle Emission, Filtration and Regeneration of Particulate Filters of Diesel and Gasoline Engines

I. Zsoldos Péter Nagy

Publication Name: Lecture Notes in Mechanical Engineering

Publication Date: 2021-01-01

Volume: 22

Issue: Unknown

Page Range: 158-173

Description:

The exhaust aftertreatment systems of diesel passenger cars have been equipped with diesel particulate filters since 2009 when the EURO 5 standard was introduced. This device is a trap for particulates, which originate from internal combustion engines in soot form. These particles must be filtered because they are able to enter the bloodstream through the human respiratory system and can cause an adverse effect on health. Investigations conducted after the 2016 diesel scandal concluded that gasoline engines with direct injection systems commonly in use today, also produce a high number of particles, therefore they must be equipped with gasoline particulate filters. The current EURO 6d TEMP regulation introduced in September 2017 specifies that the NEDC-regulation has to be replaced gradually with the WLTP investigation and the RDE realistic vehicle tests, thus making the real results of the measurements impossible to avoid. Also the particulate emission per one hundred kilometers will be observable in case of direct injection gasoline engines. This paper presents the formation of soot particles during the combustion processes of diesel and gasoline engines, the deposition of particles in particulate filters and explores and analyses the differences between the regeneration processes due to the deposition of particles.

Open Access: Yes

DOI: 10.1007/978-981-15-9529-5_14

Artificial Aging of Ultra-low Viscosity Lubricant Samples on a Programmable Oil Aging Rig

I. Zsoldos András Lajos Nagy

Publication Name: Lecture Notes in Mechanical Engineering

Publication Date: 2021-01-01

Volume: 22

Issue: Unknown

Page Range: 139-147

Description:

An artificial lubricant aging rig was developed in order to simulate aging processes of automotive lubricants. This article presents the development of the aging apparatus and its control system as well as results of artificial aging of SAE 0W-20 grade automotive lubricant with a modified thermal cycling procedure. Friction and wear measurements on a high frequency reciprocating rig were conducted to describe the lubricating properties of the artificially aged samples. Select oil samples were analyzed through FTIR spectroscopy.

Open Access: Yes

DOI: 10.1007/978-981-15-9529-5_12

Preparation of soft magnetic composite from Fe-6.9wt%Si by different heat treatment strategies.

I. Zsoldos L. K. Varga B. Kocsis

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2020-08-25

Volume: 903

Issue: 1

Page Range: Unknown

Description:

Present study investigated the effect of isothermal heat treatment strategies between 800 °C and 1150 °C on the magnetic properties of toroidal samples made from Fe-6.9wt%Si powder. The samples were prepared by classical powder metallurgy method since the classical sheet forming methods no longer work with the high silicon content. Our results presented here are part of a series of comparative experiments where we study the effectiveness of the insulating layers created during and before the compacting of soft magnetic composites (SMCs). Our goal was to create a soft magnetic composite made of ferromagnetic and inorganic insulating material with a frequency limit already in the megahertz range and a Snoek limit of few gigahertz. In the case of samples made from Fe-6.9wt%Si powder, the computed tomography results showed that significant porosity is to be expected after pressing. Its positive effect occurred during the heat treatment in the atmospheric agent, where silicon is precipitated and deposited on the surface of the particle. This coating is an electrically insulating layer at the grain boundaries. Depending on the heat treatment strategy, 1 or 2 ferromagnetic phases were observed. The frequency limit approached the target values, but due to the low value of static permeability, the Snoek limit did not reach the gigahertz range. However, there is a significant improvement in magnetic properties compared to the heat-treated samples in a protective gas.

Open Access: Yes

DOI: 10.1088/1757-899X/903/1/012042

Mechanical property evaluation of closed and open-cell foam structures with finite element method

I. Zsoldos K. Kulcsár J. Kónya

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2020-08-25

Volume: 903

Issue: 1

Page Range: Unknown

Description:

In this study, different lattice structures were examined with finite element method. Mechanical stress evaluations were performed on porous structured lattices that consisted simple cubic, face-centered cubic, body-centered cubic, and diamond unit cells. Finite element method simulations showed that structured foams with open and closed cells produced significantly different stress levels depending on their packing fraction. The aim of this study is to provide a basis for the design of an implant system that would promote the process of osseointegration.

Open Access: Yes

DOI: 10.1088/1757-899X/903/1/012010

CT-based tests and finite element simulation for failure analysis of syntactic foams

I. Zsoldos I. Kozma

Publication Name: Engineering Failure Analysis

Publication Date: 2019-10-01

Volume: 104

Issue: Unknown

Page Range: 371-378

Description:

A unique compression test was carried out on aluminium matrix syntactic foams combined with X-ray micro CT structure analysis, in order to obtain a full reconstruction of the failure process of syntactic foams. The compression test was interrupted in small compression steps and CT imaging was performed after each interruption. As a result of the reconstruction different regions of the failure process were defined. A characteristic shear plane was found as the typical deterioration place. A CAD model was generated from the CT-base reconstruction of the specimen and a finite element algorithm was run on the CAD model. It was computed from the mechanical stress distribution that the plane, having been fitted to the weakest points of the structure, is identical to the characteristic shear plane. As our results indicate, using a finite element analysis on a CT-based reconstructed model is one way to prognosticate the deterioration of a structure.

Open Access: Yes

DOI: 10.1016/j.engfailanal.2019.06.003

Fabrication of waste bagasse fiber-reinforced epoxy composites: Study of physical, mechanical, and erosion properties

Amar Patnaik Gusztáv Fekete Sachin Tejyan I. Zsoldos Vedant Singh Tej Singh

Publication Name: Polymer Composites

Publication Date: 2019-09-01

Volume: 40

Issue: 9

Page Range: 3777-3786

Description:

The aim of the research work is to study the physical, mechanical, and erosive wear properties of sugarcane bagasse fiber-reinforced epoxy composites. The physical (density, void content) and the mechanical (hardness, tensile strength, impact energy, flexural strength) properties of the composites were found to increase with the content of bagasse fiber. For erosive wear analysis, the experiments were carried out with the help of erosion test machine. To minimize the erosive wear rate, Taguchi technique is executed to explore the influence of five control factors including fiber content, impact velocity, impingement, stand-off distance, and erodent size at three levels. Using Taguchi (L27) orthogonal array, the optimal combination of control factors, which yielded minimum erosive wear rate, was statistically predicted and experimentally verified. The fiber content and impact velocity were the two most contributing control factors for the minimization of erosive wear rate. The important sequence of the parameters is fiber content > impact velocity > impingement angle > erodent size > stand-off distance. The optimal combination of control factors was obtained at 10 wt% of fiber content, 30 m/s of impact velocity, 30° of impingement angle, 85 mm of stand-off distance, and 250 μm of erodent size. Finally, composites worn surfaces were examined with scanning electron microscope to study the possible erosive wear mechanism. POLYM. COMPOS., 40:3777–3786, 2019. © 2019 Society of Plastics Engineers.

Open Access: Yes

DOI: 10.1002/pc.25239

A friction and wear study of laboratory aged engine oil in the presence of diesel fuel and oxymethylene ether

I. Zsoldos András Lajos Nagy Jan Knaup

Publication Name: Tribology Materials Surfaces and Interfaces

Publication Date: 2019-01-02

Volume: 13

Issue: 1

Page Range: 20-30

Description:

Non-fossil fuels for the commercial and passenger vehicle sector are gaining more importance due to their positive effects on exhaust gas emissions. Ongoing research investigating a broad variety of biofuels, synthetic fuels and regenerative fuels shows that a reduction of CO 2 emissions can be possible without major modifications to the existing vehicle infrastructure. An internal combustion engine is a complex system of physical and chemical mechanisms, all of which contribute to the performance output, exhaust gas composition, durability and longevity of the engine. Modifying the fuel will not only result in differing chemical reactions and thermodynamic efficiency but will also affect friction and wear through the dilution and degradation of the lubricant. This study aims to investigate the variation of friction and wear in a model system due to the introduction of oxymethylene ether and regular diesel fuel to the lubricant. High-frequency reciprocating rig experiments will be carried out on 100Cr6 steel specimen with laboratory aged fully formulated commercially available SAE 0W-20 grade engine oil containing defined amounts of OME 3−5 and regular diesel fuel. The surface of the steel specimen will be analysed using optical microscopy and scanning electron microscopy.

Open Access: Yes

DOI: 10.1080/17515831.2018.1558026

Displacement-based failure analysis of metal matrix syntactic foam

I. Zsoldos I. Kozma Dóra Harangozó H. Hargitai

Publication Name: Wit Transactions on Engineering Sciences

Publication Date: 2019-01-01

Volume: 124

Issue: Unknown

Page Range: 161-173

Description:

Metal matrix syntactic foams are being used more and more widely thanks to their relative density as well as their perfect energy-absorbing characteristics. Multiple studies concern the economical production of these materials – particularly, how energy absorption as a physical characteristic can be increased. Many studies examined the effects of material choice as well as cell size and wall thickness of reinforcing materials on compressive strength. However, there are only estimated models about descriptions concerning decaying processes of samples from different material composition and geometrical variation. In this study, we introduced an “in situ” examination in order to model the decaying process. We upsetted aluminium-ceramic composite foams cyclically. We reconstructed the geometry of the sample with microcomputed tomography (μCT) technology and digital image processing at certain specified points of the compression test. During the complete decaying process, the process was evaluated with volume change and number of broken hollow particles, as well as elementary particle displacements, orientation and sphericity of the reinforced material.

Open Access: Yes

DOI: 10.2495/MC190161

Self-organising formation of fullerene molecules from graphene patterns

I. Zsoldos István László Dávid Fülep

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

The self-organised formation of C60 and C70 from well designed graphene patterns was proved by molecular dynamic simulations. In this paper graphene nanopattern models are shown which can be used for self-organised formations of larger fullerene molecules. The rules of building of the nanopatterns are defined. Examples are shown for the self-organised processes in case of larger fullerene molecules.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012011

Structural analysis of titanium alloys

I. Zsoldos K. Kulcsár J. Kónya

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

The material of choice for dental implant devices is titanium alloy (Ti-6Al-4V). In this study, the two fundamental manufacturing technologies of dental implant prostheses are compared. Titanium alloy specimens and models were created with conventional precision casting and with modern, innovative additive manufacturing technologies. Hereupon, the microscopic analysis of specimen cut-offs was carried out. We were focusing on fundamental microstructural differences. The thus-created specimen models were subjected to tensile tests for comparative examination.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012029

A review on the effect of alternative fuels on the friction and wear of internal combustion engines

I. Zsoldos András Lajos Nagy Jan Knaup

Publication Name: Lecture Notes in Mechanical Engineering

Publication Date: 2018-01-01

Volume: 0

Issue: 9783319756769

Page Range: 42-55

Description:

The climate policy of the EU specifies strict limits for harmful exhaust gases of passenger cars and commercial vehicles. Electric Mobility plays a significant role in reaching the fleet targets, but internal combustion engines (ICEs) will still be necessary in the next 30 years in medium to long distance transportation. Within the scope of this review article, research activities concerning engine performance, exhaust emissions, friction, wear and corrosion of components in relation to drop-in fuel alternatives, as well as the impact of such fuels on the degradation of the lubricant will be presented. Production pathways and properties of alternative fuels will be briefly introduced.

Open Access: Yes

DOI: 10.1007/978-3-319-75677-6_4

Failure analysis of aluminum - Ceramic composites

I. Fekete I. Zsoldos I. Kozma

Publication Name: Materials Science Forum

Publication Date: 2017-01-01

Volume: 885

Issue: Unknown

Page Range: 286-291

Description:

The increasingly widespread use of syntactic metal foams is due to their excellent energy absorbing characteristics. Several research groups deal with developing methods that can further improve this characteristic. Several literature analyses have been devoted to the effects of materials selection, cell size and wall thickness of the reinforcing element on the compression strength. In this work an in situ test necessary for the modeling of the failure process introduced. The aluminumceramic composite foams were cyclically upset. The geometry of the test specimen was reconstructed at a certain point of the compression test by μCT technology and digital image analysis. The failure process was characterized by volume change, by the number of broken shells and by the formation of shear plane as a function of the deformation.

Open Access: Yes

DOI: 10.4028/www.scientific.net/MSF.885.286

Position sensitivity study in molecular dynamics simulations of self-organized development of 3D nanostructures

I. Zsoldos István László Dávid Fülep

Publication Name: Materials Science Forum

Publication Date: 2017-01-01

Volume: 885

Issue: Unknown

Page Range: 216-221

Description:

The sensitivity of defect free fusion of straight carbon nanotubes from graphene nanoribbons to the position of the nanoribbon edge positions has been investigated. A basic difference between the behavior of armchair and zigzag type nanoribbons was observed. When placing armchair type graphene nanoribbons above each other identical, fitting positions are obtained automatically. Zigzag type graphene nanoribbons, however, must not be placed above each other in identical positions. From the viewpoint of defect-free fusion, according to the MD simulations symmetric on nearly symmetric positions of the ribbon edges are favorable.

Open Access: Yes

DOI: 10.4028/www.scientific.net/MSF.885.216

Self-organised formation of nanotubes from graphene ribbons. A molecular dynamics study

I. Zsoldos István László Dávid Fülep

Publication Name: Materials Research Express

Publication Date: 2016-10-01

Volume: 3

Issue: 10

Page Range: Unknown

Description:

The conditions for self-organised formations of carbon nanotubes from two parallel graphene ribbons were studied in a density functional adjusted tight binding molecular dynamics simulation.Wehave found that the seemingly trivial process is significantly limited by the thermal motion of the carbon atoms. There are further difficulties as well, primarily the unfavourable position of the atoms at the edges of the zigzag graphene ribbons. In repeated molecular dynamics runs we analysed the conditions of perfect coalescences, the influence of the substrate and the impact of the zigzag graphene ribbon positions.Wehave obtained that contrary to the abovementioned unfavourable conditions perfect nanotube production can be obtained using substrates. As the positioning of the substrate can be made with piezoelectric devices, this can significantly help the experimental realisation of the nanotube formation as well.

Open Access: Yes

DOI: 10.1088/2053-1591/3/10/105044

Topological and energetic conditions for lithographic production of carbon nanotubes from graphene

I. Zsoldos István László Dávid Fülep

Publication Name: Journal of Nanomaterials

Publication Date: 2015-01-01

Volume: 2015

Issue: Unknown

Page Range: Unknown

Description:

Density Functional Based Tight-Binding (DFTB) molecular dynamics (MD) simulations were performed for producing carbon nanotubes from graphene nanoribbons. The constant temperature simulations were controlled with the help of Nosé-Hoover thermostat. In our systematic study we obtained critical curvature energies and determined topological conditions for nanotube production from two parallel graphene nanoribbons. We obtained linear relationship between the curvature energy and the square of the curvature.

Open Access: Yes

DOI: 10.1155/2015/379563

Molecular dynamics simulation of carbon nanostructures: The D5h C70 fullerene

I. Zsoldos István László

Publication Name: Physica E Low Dimensional Systems and Nanostructures

Publication Date: 2014-02-01

Volume: 56

Issue: Unknown

Page Range: 422-426

Description:

Molecular dynamics calculations can reveal the physical and chemical properties of various carbon nanostructures or can help to devise the possible formation pathways. In our days the most well known carbon nanostructures are the fullerenes and the nanotubes. They can be thought of as being formed from graphene sheets, i.e. single layers of carbon atoms arranged in a honeycomb lattice. Usually the nature does not follow the mathematical constructions. An ideal nanotube can be thought of as a hexagonal network of carbon atoms that has been rolled up to make a cylinder. There is not any theory of carbon nanotube formation which is based on this construction. Although the first time the C60 and C70 were constructed by laser irradiated graphite, the fullerene formation theories are based on various fragments of carbon chains, and networks of pentagonal and hexagonal rings. In the present article different initial patterns will be given for the formation of the C70 fullerene with D5h symmetry. The desired final structures are obtained in tight-binding molecular dynamics calculations. © 2013 Published by Elsevier B.V.

Open Access: Yes

DOI: 10.1016/j.physe.2012.08.009

Computer tomography based reconstruction of metal matrix syntactic foams

I. Zsoldos Sz Papp I. Kozma G. Dorogi

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2014-01-01

Volume: 58

Issue: 2

Page Range: 87-91

Description:

In order to create 3D (three-dimensional) models for finite element calculations it is necessary to reconstruct the structure of metal foam composites reinforced by hollow ceramic spheres. A new algorithm was developed for this reconstruction work. This algorithm is based on the investigation of sphericity of the shapes found on CT (computer tomograph) layer records. Using this algorithm a 3D CAD (computer aided design) model of acceptable precision can be constructed.

Open Access: Yes

DOI: 10.3311/PPme.7337

The role of the atomic force function in molecular mechanics simulations for carbon nanostructures

I. Zsoldos T. Pataki

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2013-12-01

Volume: 47

Issue: 1

Page Range: Unknown

Description:

Molecular mechanics studies were performed on structures consisting of Y junctions of carbon nanotubes. Tensile simulations were run on the same structure, wherein atomic force functions of various shape were used. According to the numerical test results the behavior of the structure, the failure site and the failure process could be determined irrespective of the shape of the force function. © Published under licence by IOP Publishing Ltd.

Open Access: Yes

DOI: 10.1088/1757-899X/47/1/012035

Loading simulations of carbon nanotube junctions

I. Zsoldos T. Pataki

Publication Name: Materials Science Forum

Publication Date: 2013-01-01

Volume: 729

Issue: Unknown

Page Range: 162-168

Description:

Weakest points of carbon nanotube junctions have been determined by molecular mechanical algorithms. This algorithm is based on the application of the so-called Brenner potential function, atomic forces are calculated from the derivatives of the potential function describing the energetics. Behavior of various types of symmetric Y-junctions is studied with respect to axial tensile load. © (2013) Trans Tech Publications, Switzerland.

Open Access: Yes

DOI: 10.4028/www.scientific.net/MSF.729.162

Graphene-based molecular dynamics nanolithography of fullerenes, nanotubes and other carbon structures

I. Zsoldos István László

Publication Name: Epl

Publication Date: 2012-09-01

Volume: 99

Issue: 6

Page Range: Unknown

Description:

The mass production of fullerenes and nanotubes faces the problem of their selective production. Here we present special kind of graphene patterns which can be used as initial structures for fullerenes, nanotubes and other carbon nanostructures. We proved in quantum chemical molecular dynamics calculations that these structures transform in a self-organizing way into the desired structures. Our results can initiate new experimental researches for improving the existing carbon nanostructure productions and to develop a new, structure-selective nanolithography of fullerenes, nanotubes and other carbon structures. We present such kind of graphene patterns which generate the self-organizing processes. In our molecular dynamics simulation we obtained the C 60 and C 70 fullerene, the (5,5) armchair nanotube and (9,0) zigzag nanotube. We present also a graphene pattern for self-organizing Y junction production. © Copyright EPLA, 2012.

Open Access: Yes

DOI: 10.1209/0295-5075/99/63001

Molecular dynamics simulation of carbon nanostructures: The C60 buckminsterfullerene

I. Zsoldos István László

Publication Name: Physica Status Solidi B Basic Research

Publication Date: 2012-01-01

Volume: 249

Issue: 12

Page Range: 2616-2619

Description:

Molecular dynamics calculations can reveal the physical and chemical properties of various carbon nanostructures or can help to devise the possible formation pathways. In our days the most well-known carbon nanostructures are the fullerenes, the nanotubes, and the graphene. The fullerenes and nanotubes can be thought of as being formed from graphene sheets, i.e., single layers of carbon atoms arranged in a honeycomb lattice. Usually the nature does not follow the mathematical constructions. Although the first time the C60 and the C70 were produced by laser irradiated graphite, the fullerene formation theories are based on various fragments of carbon chains and networks of pentagonal and hexagonal rings. In the present article various formation pathways for the buckminsterfullerene C60 molecule will be presented. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Open Access: Yes

DOI: 10.1002/pssb.201200125

Remarks to the topological characterization of cellular systems

I. Zsoldos T. Reti

Publication Name: Journal of Geometry and Physics

Publication Date: 2011-08-01

Volume: 61

Issue: 8

Page Range: 1476-1478

Description:

In this note we discuss and solve an open problem (a conjecture) posed in a paper "On the combinatorial characterization of quasicrystals" published earlier in the Journal of Geometry and Physics. The conjecture proved is valid for the majority of space filling cellular systems (polycrystals, nanotubes, and fullerenes). © 2011 Elsevier B.V.

Open Access: Yes

DOI: 10.1016/j.geomphys.2011.03.016

Planar trivalent polygonal networks constructed from carbon nanotube Y-junctions

I. Zsoldos

Publication Name: Journal of Geometry and Physics

Publication Date: 2011-01-01

Volume: 61

Issue: 1

Page Range: 37-45

Description:

This work is the first step towards proving that general planar polygonal networks can be constructed as patterns of carbon nanotubes. A subset of the planar polygonal networks, namely the trivalent planar networks, are studied. These patterns can be constructed from carbon nanotubes such that every intersection point of the networks is replaced with a carbon nanotube Y-junction. Accordingly the basic task is to show the basic connections of the carbon nanotube Y-junctions. The basic set of connected Y-junctions is defined and models of the structures are shown. Nanorings with two, three or more branches are constructed from two, three or more Y-junctions such that two tubes of every Y-junction are joined to the neighbouring tubes with the third tube being free. Because of the known, exceptional electronic behaviour of carbon nanotubes, combinations of basic elements of planar nanotube networks could motivate new experimental and theoretical works having the goal of finding the basic electronic tools for nanocircuits. © 2010 Elsevier B.V.

Open Access: Yes

DOI: 10.1016/j.geomphys.2010.09.008

Effect of topological defects on graphene geometry and stability

I. Zsoldos

Publication Name: Nanotechnology Science and Applications

Publication Date: 2010-12-01

Volume: 3

Issue: 1

Page Range: 101-106

Description:

The effect of two basic topological defects, mitosis and the Stone-Wales defect, is studied in the graphene structure. The topological rules of the curvatures due to the occurrence of the defects in different arrangements are determined. Despite the fact that the causes and the probability of these topological defects are not known today, this theoretical work studies the distortions caused by the defects geometry and stability of the graphene structure. © 2010 Zsoldos, publisher and licensee Dove Medical Press Ltd.

Open Access: Yes

DOI: 10.2147/NSA.S13905

Simulation of 3-dimensional cell population growth processes in polyhedral cellular systems

I. Zsoldos T. Reti

Publication Name: Materials Science Forum

Publication Date: 2007-01-01

Volume: 537-538

Issue: Unknown

Page Range: 579-590

Description:

In order to simulate the polyhedral grain nucleation in alloys, 3-D cell population growth processes are studied in space-filling periodic cellular systems. We discussed two different methods by which space-filling polyhedral cellular systems can be constructed by topological transformations performed on "stable" 3-D cellular systems. It has been demonstrated that an infinite sequence of stable periodic space-filling polyhedral systems can be generated by means of a simple recursion procedure based on a vertex based tetrahedron insertion. On the basis of computed results it is conjectured that in a 3-D periodic, topologically stable cellular system the minimum value of the average face number 〈f〉 of polyhedral cells is larger than eight (i.e. 〈f〉 > 8). The outlined algorithms (which are based on cell decomposition and/or cell nucleation) provide a new perspective to simulate grain population growth processes in materials with polyhedral microstructure.

Open Access: Yes

DOI: 10.4028/0-87849-426-x.579

On the topology of two dimensional generalized cell systems

I. Zsoldos J. Janik T. Reti

Publication Name: Recent Advances in Multidisciplinary Applied Physics

Publication Date: 2005-12-01

Volume: Unknown

Issue: Unknown

Page Range: 559-564

Description:

No description provided

Open Access: Yes

DOI: 10.1016/B978-008044648-6.50085-9

A possible extension of the Aboav-Wealre law

I. Zsoldos T. Reti

Publication Name: Materials Science Forum

Publication Date: 2005-01-01

Volume: 473-474

Issue: Unknown

Page Range: 389-398

Description:

The semi-empirical Aboav-Weaire law is generally used to characterize the local topological correlation between the neighbor cells in 2D space-filling random cellular system. Starting with a possible generalization of the Aboav-Weaire law, this paper presents a new method, which is designated primarily to the topological characterization of finite cellular systems defined on an unbounded, closed and orientable surface, and composed of a finite set of combinatorial polygons. It is demonstrated that using two simple topological parameters (AR and ER) derived from the extended Aboav-Weaire equation, the local structure and the stability of polyhedral fullerenes can be efficiently evaluated on the basis of quantitative criteria. © 2005 Trans Tech Publications, Switzerland.

Open Access: Yes

DOI: 10.4028/0-87849-957-1.389

Geometric construction of carbon nanotube junctions

I. Zsoldos T. Reti A. Szasz Gy Kakuk

Publication Name: Modelling and Simulation in Materials Science and Engineering

Publication Date: 2004-11-01

Volume: 12

Issue: 6

Page Range: 1251-1266

Description:

In this work we demonstrate that carbon nanotube junctions with an optional number, type (zigzag and/or armchair) and diameter of tubes can exist. We show a method for geometric construction of their models.

Open Access: Yes

DOI: 10.1088/0965-0393/12/6/017

Influence of Cyclic Loading on the Removal Torque of Unique Subperiosteal Implant Screws

I. Zsoldos Dávid Pammer K. Kulcsár Ádám Vörös

Publication Name: Journal of Functional Biomaterials

Publication Date: 2025-09-01

Volume: 16

Issue: 9

Page Range: Unknown

Description:

During the investigation, the effect of screw tightening torque on the potential loosening of screws under load was examined in the case of custom-made subperiosteal implants. The study focused on the connection screws between the implant components, testing the commonly applied tightening torques of 15 Ncm and 30 Ncm. Mastication was simulated using a custom-designed, PLC-controlled testing device, which allowed for the reproduction of variable numbers, forces, and speeds of bite cycles. With this device, six different scenarios were tested, including 500, 2000, and 10,000 bite cycles, under both constant and variable bite forces. A caliper was used to record potential length changes of the screws, force sensors measured the bite forces, and calibrated torque screwdrivers were used to verify the loosening torques. Based on the analysis of the measured data, it was concluded that for the M1.8 screws tested, a tightening torque of 15 Ncm does not provide sufficient resistance against loosening, whereas 30 Ncm offers adequate stability.

Open Access: Yes

DOI: 10.3390/jfb16090306