Rajmund Kuti

57202081733

Publications - 31

Fire simulation of different complex geometry tree objects using FDS

F. Hajdu Rajmund Kuti Cs Papp

Publication Name: Pollack Periodica

Publication Date: 2025-06-27

Volume: 20

Issue: 2

Page Range: 67-72

Description:

Fire simulations are becoming more and more widely used in fire protection practices. In order to achieve more accurate results, it is inevitable that simulations are always developed. This study investigates the fire behavior of various complex wooden geometries. This research aims to enhance the understanding of fire propagation of different geometries made of wood. The simulations are performed using fire dynamics simulator, which incorporates heat transfer, combustion, and fluid dynamics principles. Key parameters like temperature and heat release rate are analyzed for each of tree geometries. The research contributes to the development of more accurate fire models. It also provides the basis for further development of simulations including more complex geometries.

Open Access: Yes

DOI: 10.1556/606.2024.01225

Tribological Investigation of the Effects of Engine Oil Additives for Vintage Gasoline Engines

Rajmund Kuti Árpád Tóth Máté Tóth Cs Papp

Publication Name: Fme Transactions

Publication Date: 2025-01-01

Volume: 53

Issue: 1

Page Range: 31-37

Description:

Restoration of vintage vehicles is becoming more and more popular nowadays. Conditions of usage and operation changed throughout recent years, factory recommended lubricants and fuels are no longer available. The usage of improper lubricants can lead to severe engine damages. The aim of our research is to conduct the analytical and tribological investigation of the lubricant used in a Triumph SC 1300 type four-stroke gasoline engine assembled with two carburetors. Our further task is to conduct analytical and tribological investigation of engine oil that we infused with MoS2 to compare it with the oil in accordance with factory parameters after defined test operation. After the analysis and evaluation of results we serve with recommendations in connection with the given engine to operate it with the most appropriate engine oil regarding operation conditions.

Open Access: Yes

DOI: 10.5937/FME2501031K

Innovative wireless sensing for modal analysis and damage modeling of Petőfi Bridge

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Results in Engineering

Publication Date: 2024-12-01

Volume: 24

Issue: Unknown

Page Range: Unknown

Description:

The historic Petőfi Bridge (1933), a steel truss structure in Győr, Hungary, exemplifies the vulnerability of truss-type bridges to both local and total collapse. This study introduces an innovative, low-cost, accurate, and scalable wireless sensing system (WSS) for Structural Health Monitoring (SHM), utilizing the Petőfi Bridge as a case study. The research details the architecture and workflow of the system, with experimental validations confirming the accuracy of measured acceleration responses. The main natural frequencies of the bridge were estimated by processing the collected data, showing a strong correlation with reference values obtained through conventional wired systems. A calibrated high-fidelity finite element model analyzed the sensitivity of bridge damage detection indicators. The study explores variations in vertical displacement, and modal frequencies, and validates an approach based on displacement influence lines (DILs). The findings indicate the varying efficacy of these indicators in detecting structural damage, providing critical insights for advancing SHM practices.

Open Access: Yes

DOI: 10.1016/j.rineng.2024.103527

Comparison of different geometry trees in fire simulation

L. Környei Csaba Hajdu F. Hajdu Rajmund Kuti Dóra Beke

Publication Name: Pollack Periodica

Publication Date: 2024-10-16

Volume: 19

Issue: 3

Page Range: 34-39

Description:

Wildfire simulations can help to better understand the dynamics and effects of forest fires. The basis of wildfire simulation is the tree-burning simulation. In this paper, the fire simulation of 7 different geometry Hungarian trees in the case of arson is presented. It was observed that the trees were burned down fast. The maximum mass loss rate and maximum heat release rate were larger as the tree was larger. The largest intensity fire could be observed in the case of the smallest tree. The maximum temperature was higher in the case of a large crown diameter. The maximum aerosol reached high pollutant concentrations. In the case of large crown height, the maximum CO2 concentration was higher. The results presented in this paper can be the basis of the following forest fire simulations.

Open Access: Yes

DOI: 10.1556/606.2024.01022

One-at-a-Time sensitivity study of a tree burning simulation

L. Környei F. Hajdu Rajmund Kuti

Publication Name: Pollack Periodica

Publication Date: 2024-03-22

Volume: 19

Issue: 1

Page Range: 53-59

Description:

The aim of the research was to carry out the One-at-a-Time sensitivity analysis of a tree burning experiment simulation with a novel fuzzy logic-based method. It was observed that the precent of the remaining tree is sensitive to the moisture content, the crown-base diameter and the tree height. The other variables, which are maximum mass loss rate, maximum heat release rate, and maximum temperature at the top of the tree are moderately sensitive or not sensitive to the selected parameters. The presented results can be used in sensitivity studies and wildfire simulations.

Open Access: Yes

DOI: 10.1556/606.2023.00850

Multi-Span Box Girder Bridge Sensitivity Analysis in Response to Damage Scenarios

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Buildings

Publication Date: 2024-03-01

Volume: 14

Issue: 3

Page Range: Unknown

Description:

Due to their distinct features, including structural simplicity and exceptional load-carrying capacity, steel box girder bridges play a critical role in transportation networks. However, they are categorized as fracture-critical structures and face significant challenges. These challenges stem from the overloading and the relentless effects of corrosion and aging on critical structural components. As a result, these bridges require thorough inspections to ensure their safety and integrity. This paper introduces generalized approaches based on vibration-based structural health monitoring in response to this need. This approach assesses the condition of critical members in a steel girder bridge and evaluates their sensitivity to damage. A rigorous analytical evaluation demonstrated the effectiveness of the proposed approach in evaluating the Szapáry multi-span continuous highway bridge under various damage scenarios. This evaluation necessitates extensive vibration measurements, with piezoelectric sensors capturing ambient vibrations and developing detailed finite element models of the bridge to simulate the structural behavior accurately. The results obtained from this study showed that bridge frequencies are sufficiently sensitive for identifying significant fractures in long bridges. However, the mode shape results show a better resolution when compared to the frequency changes. The findings are usually sensitive enough to identify damage at the affected locations. Amplitude changes in the mode shape help determine the location of damage. The modal assurance criterion (MAC) served to identify damage as well. Finally, the results show a distinct pattern of frequency and mode shape variations for every damage scenario, which helps to identify the damage type, severity, and location along the bridge. The analysis results reported in this study serve as a reference benchmark for the Szapáry Bridge health monitoring.

Open Access: Yes

DOI: 10.3390/buildings14030667

Truck Load Positions Effect on Dynamic Behavior of Fractured Steel Box Girder Bridge

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 67-74

Description:

The harsh climate and environmental hazards contribute to the structural damage of steel bridges. Substantial dynamic loading from heavy trucks can worsen existing cracks. This paper investigates the dynamic behavior of a steel box girder bridge, the Szapáry bridge, with a fractured girder subjected to moving truck loads. Initially, a finite element model simulates the seven-span continuous bridge behavior during static load testing. The model also accurately simulated the dynamic load tests performed. A series of hypothetical damage (fractured girder) and dynamic loading scenarios reveal the effects of truck positions on the damaged bridge's dynamic response. Dynamic displacement induced due to traffic loading helps evaluate a bridge's structural health. Results of the parametric analysis highlight that several factors, including truck velocity and position, bridge span length, and truck lateral spacing, significantly affect the dynamic vibration of the fractured bridge. The results offer insight into the effectiveness of dynamic response analysis for conditioned-based maintenance and damage detection.

Open Access: Yes

DOI: 10.3233/ATDE240528

Selection of Engine Oils with Tribological Examinations Applicable to Specially Operated Diesel Engines

L. Földi Rajmund Kuti Árpád Tóth L. Csapó F. Könczöl Cs Papp

Publication Name: Fme Transactions

Publication Date: 2024-01-01

Volume: 52

Issue: 2

Page Range: 335-342

Description:

In recent times, many specially engineered diesel engines built in the 1980s are still used in different areas, for which the suggested engine oils are no longer available. These engines are operated reliably in military combat vehicles, electricity generators, and tracked machinery, thus it is essential to examine what engine oils are suitable for their operating conditions and may be used as their engine oil. The aim of our research is to conduct the tribological examination of an oil sample taken from a V-6M type naturally aspirated Diesel engine and the oil prescribed by the manufacturer. After evaluating the results, we determine which type of oil is applicable in the engine to achieve safe operation and a long lifetime.

Open Access: Yes

DOI: 10.5937/fme2402335K

Investigation of combustion gases of Li-ion, Ni-Cd and Pbq batteries

Rajmund Kuti Zsuzsanna Kerekes Cs Papp István Benke

Publication Name: Pollack Periodica

Publication Date: 2023-07-11

Volume: 18

Issue: 2

Page Range: 101-106

Description:

Appliances used in everyday life, like smart phones, notebooks; do-it-yourself machineries usually operate with battery instead of power supply. It means comfort to users however; they expose them to different dangers. In the last few years, several fire cases happened in connection with these appliances while charging and usage, which have driven the attention to the dangers of battery technology. Regarding the actuality of the topic, combustion products developing during the burning process of batteries with 1:1 ratio burning experiments were investigated, experiences and results from that are represented in this paper. The aim of the research is to call the attention to the flammability properties of lithium-ion and other batteries, the possible dangers and in case of fire to support the involved personnel.

Open Access: Yes

DOI: 10.1556/606.2022.00638

INVESTIGATION OF TRAFFIC INDUCED DYNAMIC RESPONSE OF A BRIDGE

Zoltán Major P. Szalai Péter Horváth F. Hajdu Rajmund Kuti M. Brinissat Antal Apagyi Cs Papp

Publication Name: Strojnicky Casopis

Publication Date: 2023-05-01

Volume: 73

Issue: 1

Page Range: 85-102

Description:

Bridges are special structures that provide a transport connection between areas divided by a physical barrier. Vehicles passing over bridges cause vibrations in the structural elements of the bridge, which can damage these structural elements over time. The aim of our research was to investigate the vibrations generated by vehicles on Hungary's first steel girder welded bridge, which was subjected to the maximum allowable load. In this paper, we describe the measurements we have carried out, analyse the results, present the vehicle-bridge interaction model we have constructed and the computer simulation we have carried out by using it. Our research results are intended to contribute to accident prevention and the safe operation of bridges.

Open Access: Yes

DOI: 10.2478/scjme-2023-0007

Evaluation of the Szapáry Long-Span Box Girder Bridge Using Static and Dynamic Load Tests

Rajmund Kuti M. Brinissat R. P. Ray

Publication Name: Infrastructures

Publication Date: 2023-05-01

Volume: 8

Issue: 5

Page Range: Unknown

Description:

This paper presents the results of a recent field test carried out before the opening phases of the Szapáry motorway bridge across the Tisza River in central Hungary. The evaluation test was based on static and dynamic load tests that provided information on deflection, stresses, and dynamic mode shapes along the bridge. The structure has two large continuous independent steel box girders that cover spans across the floodplain and river. Various configurations of truck loading applied up to 6400 kN of loading on the deck. During the static tests, string potentiometers recorded deflections at mid-span. Additionally, strain gauges enabled strain/stress measurements at the mid-point of the longest span and directly above one support. Dynamic loadings showed variation in deflection response due to vehicle speed, and ambient vibration testing led to determining vibration modes and frequencies. A three-dimensional finite-element model produced similar deflections, stresses, and modal behavior. Measured and modeled deflections and stresses indicated that the bridge performed within design margins. The testing and analysis results will be part of a future program assessing conditioned-based maintenance.

Open Access: Yes

DOI: 10.3390/infrastructures8050091

Numerical Examination of a Forest Area Fire

L. Környei Csaba Hajdu F. Hajdu Rajmund Kuti Dóra Beke

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 61-66

Description:

An important task of sustainability is the protection of Earth's forests and the prevention of forest fires. In this paper, the numerical examination of a typical Hungarian ash forest fire is presented. The connection between sustainability and forest fire simulations is also discussed. For the simulation, a Fire Dynamics Simulator was selected, and a particle-based model was used. The simulation setup, which includes a random location of trees following Poisson distribution, is also explained. Then, the simulation of a 10x10 m area of ash forest is presented. It was found that in case of arson, the fire spreads rapidly among the trees, and there will be a high-intensity fire in which the forest area burns down in 4 min. The mass loss rate, the temperature, and the heat release rate also increased fast (above 50 kg/s, above 2,000 °C and above 800,000 kW). The aerosol concentration reached a high pollutant concentration (1.3x10-6), and the carbon dioxide concentration also increased significantly (above 14,000 ppm). These changes have a direct effect on climate change. Therefore, it is important to examine them in a simulation environment. The simulation was compared to a pine tree forest simulation, and it could be observed that in the case of the pine tree, the values are similar, but phenomena occur faster. With the computer simulation, it is easier to determine the areas affected by the fire, which also helps fire prevention and firefighting. The aim of the research is to contribute to the prevention and more efficient extinguishment of wildfires and the sustainability of the Earth.

Open Access: Yes

DOI: 10.3303/CET23107011

Examination of effects of indoor fires on building structures and people

L. Környei Csaba Hajdu F. Hajdu Geza Zolyomi Rajmund Kuti Gabriella Lászlo

Publication Name: Heliyon

Publication Date: 2023-01-01

Volume: 9

Issue: 1

Page Range: Unknown

Description:

The scientific study of the harmful effects of indoor fires on building structures and on the environment is a top issue today. Indoor fires frequently occur all over the world. The goal of our research is to examine the effects of an average room fire on the survival possibility of a trapped person and on the building structure, taking into account features of the Eastern European architecture. First, a computational fluid dynamics (CFD) simulation was performed to examine the change of temperature, oxygen, and carbon monoxide concentration in a selected room in a vacant building used for military training. Based on the results, a 1:1 scale fire experiment was carried out with the parameters used in the simulation. The experiment was repeated once with the same settings. It was observed that without the intervention of firefighters, the temperature in the experiment could have rapidly reached 400 °C, as suggested by the simulation, which could have caused structural damage to the building. Furthermore, after 3 min the carbon monoxide concentration reached 400 ppm in both experiments and the simulation, which is a harmful level to people trapped inside the room. Also, in the experiment there was sufficient oxygen at the ground level with what people can survive 3 min.

Open Access: Yes

DOI: 10.1016/j.heliyon.2022.e12720

Analysis of composite bridge deck considering the effects of concrete cracking

Rajmund Kuti Mohammed El Mehdi Bichikhi M. Brinissat

Publication Name: Pollack Periodica

Publication Date: 2022-12-31

Volume: 17

Issue: 3

Page Range: 53-58

Description:

Cracking in composite steel-concrete bridge decks is a common problem in civil engineering. Before, or shortly after, the bridge is subjected to live loads; various levels of cracking can appear, mostly due to plastic shrinkage and temperature effects. This paper presents an investigation of the behavior of cracked concrete in a composite deck slab of a railway bridge supported by steel girders using the finite element method. Eurocode 4-2 proposes a few simplified methods for calculating shrinkage and cracking effects in concrete. Through the proposed methods of analysis, an analytical simulation of a continuous composite steel-concrete bridge deck is performed and some practical recommendations for analyzing beam girders of this type are given.

Open Access: Yes

DOI: 10.1556/606.2022.00573

Experimental Investigation of Tribological Properties of Two Fully Formulated Engine Oils with Additional Nanoscale Spherical Zirconia Particles

Rajmund Kuti Árpád Tóth I. Szabó

Publication Name: Lubricants

Publication Date: 2022-10-01

Volume: 10

Issue: 10

Page Range: Unknown

Description:

Decreasing harmful emissions of vehicle engines is becoming more and more challenging due to stricter standards. A possible solution is to improve the tribological attributes of lubricants, which can be achieved through the application of appropriate additives. According to preliminary studies conducted by the authors, ZrO2 (zirconium-dioxide) nano-sized ceramic particles as lubricant additives have overwhelmingly positive tribological attributes in the presence of non-metallic superficial materials. Additive concentration, as well as cross-effects with other additives were investigated in order to determine a formulation resulting in optimal tribological attributes. In this paper, the experimental investigation of ZrO2 nano-ceramic powder as a lubricant additive is presented. The tribological performance of individually samples were experimentally investigated on a ball-on-disc translational tribometer. The experiments revealed an optimal additive content of 0.3 wt%. Increasing the quantity of additives further ruined friction and wear properties of the examined tribological system.

Open Access: Yes

DOI: 10.3390/lubricants10100246

Experimental study on examining the fire load of a small compartment

F. Hajdu Rajmund Kuti Gabriella Lászlo

Publication Name: Pollack Periodica

Publication Date: 2022-04-30

Volume: 17

Issue: 1

Page Range: 133-138

Description:

In Hungary a lot of people live in condominiums or in block of flats where fire often occurs despite of precise design and effective fire protection arrangements. This means a hazard for the people living there, for the building constructions and also for the environment. A deeper knowledge of the burning process and examining the negative effects of fire load on building constructions with scientific methods are actual questions nowadays. In order to get to know the phenomena more accurately, fire spread in a bedroom was modeled and numerical simulation was carried out, which is presented in this paper in detail. These experiences may help increasing the fire safety and preventing fires in apartments. The simulations were carried out considering the characteristics of the Hungarian architecture.

Open Access: Yes

DOI: 10.1556/606.2021.00422

Tribological Properties of the Nanoscale Spherical Y2O3 Particles as Lubricant Additives in Automotive Application

Rajmund Kuti Máté Zs Leskó Árpád Tóth Jan Rohde-Brandenburger I. Szabó

Publication Name: Lubricants

Publication Date: 2022-02-01

Volume: 10

Issue: 2

Page Range: Unknown

Description:

The continuous tribological development of engine lubricants is becoming more and more vital due to its fuel efficiency improvement and lifetime increasing potential. The antiwear additives play a high role in the lubricants to protect the contacting surfaces even in the presence of thinner oil film. Nanoscale spherical particles in the lubricant may increase the necessary protecting effect. This paper presents the results of the experimental tribological investigation of nanoscale spherical Y2O3 (yttria) ceramic particles as an engine lubricant additive. The ball-on-disc tribological measurements have revealed an optimum concentration at 0.5 wt% with about 45% wear scar diameter and 90% wear volume decrease, compared to the reference, neat Group III base oil. The high-magnitude SEM analysis revealed the working mechanisms of yttria: the particles collected in the roughness valleys resulted in a smoother contacting surface, they were tribo-sintered and they have also caused slight plastic deformation of the outer layer of the metallic surface.

Open Access: Yes

DOI: 10.3390/lubricants10020028

Detection of the Possible Engine Damages in Case of a Continuous Track Military Vehicles with Tribological Investigations

L. Földi Rajmund Kuti Árpád Tóth L. Csapó F. Könczöl

Publication Name: Fme Transactions

Publication Date: 2022-01-01

Volume: 50

Issue: 3

Page Range: 526-534

Description:

Detecting the engine failures of the continuous track military vehicles is challenging because their engines are always built-in narrow places covered with armored plates. In the case of the older engines, modern computer diagnostics cannot be used for failure analysis; the solution for these tasks is the visual analysis with the engine disassembly. A possible cost-effective failure analysis method can be the tribological and chemical analysis of the used oil from the engine, which can eliminate the engine disassembly work and as the results of the chemical oil analysis can also provide information about possible fuel or cooling water dilution or the increased wear of engine components. The main goal of this article is to present the failure analysis method through the tribological investigation of the engines of two PTSZ-M type medium-tracked amphibious military transport vehicles.

Open Access: Yes

DOI: 10.5937/fme2203526K

Heat radiation effects on insulating materials used in buildings

F. Hajdu Rajmund Kuti Gabriella Lászlo

Publication Name: Pollack Periodica

Publication Date: 2021-12-31

Volume: 16

Issue: 3

Page Range: 108-113

Description:

In recent years, in order to increase the energy efficiency of older buildings in Hungary, several tenders have supported the modernization of the thermal insulation. Various thermal insulation materials have been installed on walls, on slab and on floor. Unfortunately there are cases where thermal insulation materials are not installed in accordance with the construction permit or the manufacturer's instructions, which poses a serious danger in case of a fire. During the research the effects of heat on the behavior of Expanded PolyStyrene, a thermal insulation material often used in Hungary is examined. Laboratory tests and computer simulations were carried out, which are presented in detail in this paper. The aim of the research is to contribute to increase the fire safety of buildings.

Open Access: Yes

DOI: 10.1556/606.2021.00377

Development of comparative investigation method for timing chain wear analysis using oscillating tribometer

Csaba Tóth-Nagy Rajmund Kuti Jan Rohde-Brandenburger L. Paulovics

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-11-24

Volume: 14

Issue: 4

Page Range: 406-423

Description:

This paper presents the development of a test procedure to investigate timing chain components under abrasive stress on a tribometer. Engine developers use cost and time expensive engine dynamometer tests to investigate timing chain life expectancy under different conditions. Tribometer tests are fast and cost effective, but these use standardized specimen material and geometry that greatly differ from the original tribological system of the timing chain. Manufacturing specimens from the original chain material using the original technology is complicated; surface quality and hardness properties cannot be guaranteed. The aim of research was to develop a test method for rapid and cost-effective comparison of engine lubricants, timing chain materials or coatings, as well as to assess the wear resistance of the chain to contaminants. Various uncontaminated and carbon black blended lubricants were compared using standard-based ball-on-disc tribometer tests to tribometer tests using actual timing chain components (bush-on-pin test) of a Diesel engine. Lubricants were ranked in terms of coefficient of friction and wear. Results showed that bush-on-pin tests were comparably suitable for testing lubricants when evaluated against standard ball-on-disc tribometer tests.

Open Access: Yes

DOI: 10.14513/actatechjaur.00620

Dynamic seismic analysis of bridge using response spectrum and time history method

Rajmund Kuti M. Brinissat Z. Louhibi

Publication Name: Acta Technica Jaurinensis

Publication Date: 2021-05-26

Volume: 14

Issue: 2

Page Range: 171-185

Description:

Dynamic analysis is very important to better understand the performance of structural elements of a bridge. For this purpose, a seismic analysis of an Algerian highway bridge designed with the new Algerian seismic bridge regulation (RPOA-2008) was carried out using linear and nonlinear analyses. Therefore, response spectrum, time history analyses were performed to evaluate the seismic responses of the designed bridge. The performance of the designed bridge is assessed using 10 ground motion records. The proposed methodology allows an efficient comparison of the seismic response of the bridge in terms of base shear forces, bending moment and displacements. Finally, the paper concludes with a discussion of the specific outcomes.

Open Access: Yes

DOI: 10.14513/actatechjaur.00595

Modelling and Sensitivity Analysis of Nonlinear Firefighting Systems Using Maple

F. Hajdu Rajmund Kuti G. Molnárka

Publication Name: Communications in Computer and Information Science

Publication Date: 2021-01-01

Volume: 1414

Issue: Unknown

Page Range: 234-251

Description:

Mathematical modelling and numerical simulations have greatly contributed to the development of technical sciences in the recent decades. With powerful tools, like Maple, the examination of ever newer engineering applications in simulation environment was made possible. This paper gives an overview of mathematical modelling and numerical examination of nonlinear fire truck suspension systems using Maple. The examined models are the suspension system of a heavy-duty fire truck with different degrees of freedom and a special double-cabin fire truck suspension system with a crew compartment. The construction of mathematical models, their implementation to Maple and the numerical simulation results are explained. Detailed One-at-a-Time sensitivity analysis results using a novel fuzzy logic based evaluation method developed in Maple are also presented. With the proposed method an extended parameter range can be examined and the parameters can be easily compared. From the sensitivity analysis it was concluded that the spring characteristics and the road models greatly affect simulation results.

Open Access: Yes

DOI: 10.1007/978-3-030-81698-8_16

Tribological Investigation of Applicability of Nano-Sized Cupricoxide (CuO) Ceramic Material in Automotive Vehicles

Rajmund Kuti Árpád Tóth Jan Rohde-Brandenburger I. Szabó

Publication Name: Fme Transactions

Publication Date: 2021-01-01

Volume: 49

Issue: 2

Page Range: 335-343

Description:

Due to the continuously increasing requirements of the internal combustion engines, the lubricants and their additives have to be further developed. One possible solution is the application of ceramic nanoparticles as friction modifier and wear decreaser additives. This paper presents the tribological investigation of cupricoxide (CuO) nanoparticle mixed in neat Group 3 base oil. To analyse its properties, simplified ball-on-disc friction experiments were carried out in the tribological laboratory in the Széchenyi István University in Győr, Hungary. The arisen wear scars were analysed with different, highresolution microscopes to understand the working mechanism of the nanoparticles. The results have indicated an optimum concentration of nanoparticles at 0.5wt% where both the average friction coefficient and the wear scar diameter were reduced by 15%. The microscopical investigation revealed the reduction of copper material from the CuO material, and it has mended to the rubbing surface forming a protective film on the metal surface.

Open Access: Yes

DOI: 10.5937/fme2102335T

Tribological Properties of Nano-Sized ZrO2 Ceramic Particles in Automotive Lubricants

Rajmund Kuti Árpád Tóth I. Szabó

Publication Name: Fme Transactions

Publication Date: 2021-01-01

Volume: 49

Issue: 1

Page Range: 36-43

Description:

The demand for decreasing CO2-emission and harmful material content of the exhaust gas of passenger cars requires the improvement of the entire powertrain including the applied lubricants. One of the possible future engines lubricant can be the nano-sized ceramic particles, which can provide positive tribological properties also in the presence of nonmetallic surface materials. This paper presents the experimental investigation of ZrO2 nanoceramic powder as a lubricant additive. The tribological performance of the lubricant samples was experimentally investigated on a ball-on-disc translation tribometer. An optimum concentration was found at 0.4 wt%, where the wear scar diameter on the ball specimen was reduced by more than 40% compared to the reference sample. The SEM-analysis confirmed the mending mechanism theory: nanoparticles were revealed to aggregate between the asperities resulting in a significantly smoother contact surface.

Open Access: Yes

DOI: 10.5937/FME2101036T

Identification of Engine Damages of Vintage Vehicles with Tribological Examination

Rajmund Kuti Cs Papp

Publication Name: Fme Transactions

Publication Date: 2021-01-01

Volume: 49

Issue: 3

Page Range: 608-614

Description:

Nowadays, keeping vintage vehicles in operation is becoming more and more popular, however, the reparation of occurring engine malfunctions, and the supply of particulate engine parts mean severe expenses to the owners. In case of older engines, the failure detection is not performed with the help of computerized diagnostics. In several cases the detection of failure is only possible with the disassembly of the engine. A cost-effective solution may be the application of tribological examinations, with which, the malfunctions may be revealed without the needless disassembly of the engine. The purpose of our research is to represent through the tribological examination of a VAZ-2101 (also known as Lada) engine type the practical application of the method, data analysis, evaluation of results and the steps of failure detection.

Open Access: Yes

DOI: 10.5937/fme2103608P

Investigation of swings caused by sudden wind loads during operation of an aerial ladder

Péter Horváth F. Hajdu Rajmund Kuti

Publication Name: Fme Transactions

Publication Date: 2020-01-01

Volume: 48

Issue: 2

Page Range: 351-356

Description:

In Hungary, as in other countries around the world, intervention firefighting units often use a mechanically operated aerial ladder for highaltitude rescue tasks. The safe operation of the equipment is only possible under strict safety regulations and requires a high level of expertise from the operating staff. During each intervention, extraordinary events such as sudden wind gusts can occur, which can cause extreme overload of the structural members of aerial ladders and have adverse effects on the equipment that can lead to malfunctions and-even worse-to accidents. Therefore it is important to study the consequences of external influences on aerial ladders during operation. The examination was performed on a widely used Magirus M32-L aerial ladder. The reason for choosing this type of aerial ladder is because it has a wide operating range, therefore test results can be a good starting point for other similar equipment as well. In this paper the development of our beam model and the performed finite element simulations are presented. The aim of the research is to develop a model based on geometrical measurement data that is suitable for studying the effects of wind gusts on the ladder structure. With our research, we aim to contribute to the safe operation of aerial ladders and to prevent possible accidents.

Open Access: Yes

DOI: 10.5937/FME2002351H

One-at-a-time sensitivity study of a nonlinear fire truck suspension model

F. Hajdu Rajmund Kuti G. Molnárka

Publication Name: Fme Transactions

Publication Date: 2020-01-01

Volume: 48

Issue: 1

Page Range: 90-95

Description:

In this paper the detailed OAT (one-at-a-time) sensitivity analysis of a nonlinear fire truck suspension system is carried out with numerical simulation. As output to measure sensitivity the RMS of acceleration was chosen, which can be calculated with numerical simulations easily. The degree of sensitivity was measured with a sensitivity index and based on it sensitivity Fuzzy-sets were established. The membership of each parameter to the Fuzzy sets is calculated and based on it, it was determined which parameters are the most sensitive. With the presented results it is shown that the proposed method is suitable for testing mathematical models as well.

Open Access: Yes

DOI: 10.5937/fmet2001090H

Shelf life of bottled water – field conditions in Hungary

Rajmund Kuti Judit Molnár Bendegúz Papp Rita Molnár Dóra Beke

Publication Name: Journal of Food and Nutrition Research

Publication Date: 2020-01-01

Volume: 59

Issue: 4

Page Range: 361-366

Description:

Professional soldiers and firefighters are deployed to deal with the consequences of various disasters, where their supply is carried out under field conditions. This study investigated whether improperly stored bottled drinking water can change its quality and pose a biological hazard. Microbiological quality of 20 samples of bottled mineral water produced in Hungary, including 10 uncarbonated, 5 carbonated and 5 flavoured mineral water samples, was investigated under field conditions. Culturable microorganisms were enumerated by ISO 6222:1999; coliforms and Escherichia coli by ISO 9308-1:2000; Pseudomonas aeruginosa by ISO 16266:2006; Enterococcus spp. by ISO 7899-2:2000; and Clostridium perfringens by ISO 14189:2013. In six cases among uncarbonated water samples, the aerobic colony counts exceeded the standard value. Furthermore, coliforms and P. aeruginosa were detected in three cases. However, in carbonated and flavoured mineral water, no samples of unacceptable bacteriological quality were observed, as their pH value was significantly lower and that probably did not favour proliferation of bacteria. Due to their acidic condition, carbonated and flavoured mineral water appears to be less vulnerable to microbiological contamination under field conditions. During flood damage remediation, it is advisable to perform the supply of intervention units with carbonated and flavoured mineral water to avoid infection.

Open Access: Yes

DOI: DOI not available

Parameter identification of a fire truck suspension for vibration analysis

P. Szalai F. Hajdu Rajmund Kuti Péter Mika

Publication Name: Pollack Periodica

Publication Date: 2019-01-01

Volume: 14

Issue: 3

Page Range: 51-62

Description:

In case of field measurement it is essential to determine the measurement conditions. With accurate parameter identification credible measurement and simulation results can be achieved. In this paper the parameter identification of a CSD-755-10 heavy-duty fire truck suspension for vibration analysis is presented, which is an important base-point for further research.

Open Access: Yes

DOI: 10.1556/606.2019.14.3.6

Assessing the impact of positive pressure ventilation on the building fire - A case study

O. Kegyes-Brassai Geza Zolyomi Rajmund Kuti

Publication Name: International Journal of Geomate

Publication Date: 2018-01-01

Volume: 15

Issue: 48

Page Range: 16-21

Description:

Closed-space fires often occur in Hungary, so it is necessary to examine the effects of fires on building structures, taking into account Hungarian architectural features. Fires inside the buildings are characterized by intense heat development and smoke generation that can cause permanent damage to the building structures. Heat and smoke extraction during fire extinguishing is based usually on natural ventilation. Not only being a non-effective process also makes it more difficult to accomplish firefighting tasks. Experiments in this research have been conducted with mobile positive pressure ventilation (PPV) in order to increase the efficiency of the firefighting process and to reduce the adverse effects of fires. The tests have been carried out in unused buildings, providing real conditions. Practical application has been examined in order to reduce the harmful effects of closed-space fires and to provide guidance for professional use. This research based on observations and experiments contributes to enhancing fire safety.

Open Access: Yes

DOI: 10.21660/2018.48.18042

Determination of Measurement Parameters for Vibration Analysis by Bus

P. Szalai Péter Horváth F. Hajdu Rajmund Kuti M. Brinissat Antal Apagyi Cs Papp

Publication Name: Strojnicky Casopis

Publication Date: 2022-11-01

Volume: 72

Issue: 2

Page Range: 189-200

Description:

From the point of view of field examinations, especially in the case of measurements done by instruments, it is crucially important to determine measurement conditions. Accurate identification of parameters enables accurate and certified measurement results to be achieved. In our work, we represent the determination of measurement conditions for harmful vibrations occurring during urban road transport of an Ikarus 55 type long-haul bus. This is a favourable basis for further vibration analysis regarding other buses.

Open Access: Yes

DOI: 10.2478/scjme-2022-0028