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Publications - 6374

Tribological Investigation of Base Oil Supplemented with Zirconia Nanoparticles at Various Operating Temperatures †

I. Szabó Márk Marsicki

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This study examines oil samples with zirconium dioxide (ZrO2) nanoparticles in Group III base oil at different temperatures, revealing the effects of temperature and concentration on the tribological system. The samples contain 0.1% and 1% ZrO2 nanoparticles, tested at 40–120 °C. The friction results showed that the nanoparticles increase the friction absolute integral values at all tested temperatures; however, static friction can be improved by 3–13%. The study demonstrates the wear-resistant effect of ZrO2 nanoparticles. Significant wear reduction can be achieved even at low concentrations; wear volume can be reduced by 21–87% depending on the nanoparticle concentration and operating temperature. Scanning electron microscopy with EDX helped to identify wear types, the processes occurring on the surfaces, and the percentage of nanoparticles on the surface.

Open Access: Yes

DOI: 10.3390/engproc2024079035

The Effect of Ascorbic Acid on Salt Tolerance and Seedling Performance in Triticum durum Defs. ‘Douma 3’ Under Salinity Stress in Syria

Nour Ali Tarek Alahmad Aïda Jalloul A. Nyéki

Publication Name: Agronomy

Publication Date: 2024-12-01

Volume: 14

Issue: 12

Page Range: Unknown

Description:

This study was conducted to evaluate the laboratory tolerance of the durum wheat cultivar (Douma 3) when treated with two levels of ascorbic acid (5 ppm and 10 ppm, in addition to a control treatment soaked in water) under two levels of salt stress (50 mM and 100 mM NaCl, in addition to a control). The experiment took place at the Field Crops Department labs, Faculty of Agricultural Engineering, University of Damascus, during the 2022–2023 agricultural season. The aim was to study the effect of ascorbic acid on seed reserve utilization efficiency, peroxidase enzyme activity, and its role in salt stress tolerance. The experiment followed a randomized complete block design (RCBD) using factorial ANOVA with two replicates. The results showed significant differences between the treatments, with the priming of seeds soaked in a 5 ppm ascorbic acid solution (A1) significantly outperforming in terms of seedling dry weight (22.67 mg/seedling), remaining seed dry weight (7.5 mg/seed), seed reserve utilization efficiency (0.47 mg/mg), and salt tolerance index (89.80%). Simple correlation analysis showed a significant positive correlation between seedling dry weight (SDW), seed reserve utilization efficiency (SRUE) (0.881), and salt tolerance index (STI) (0.746 *). However, a negative and non-significant relationship was observed between the remaining seed dry weight (RSDW) and other traits. Moreover, SRUE had a significant positive correlation with STI (0.814). Both total soluble protein concentrations and peroxidase enzyme activity increased under salt stress conditions following pre-treatment with ascorbic acid compared to the control. The highest protein concentration and peroxidase enzyme activity were observed with the 5 ppm ascorbic acid treatment (A1).

Open Access: Yes

DOI: 10.3390/agronomy14122982

Soil shear modulus from resonant column, torsional shear and bender element tests

Peter Hudacsek Zsolt Szilvágyi R. P. Ray

Publication Name: International Journal of Geomate

Publication Date: 2016-01-01

Volume: 10

Issue: 2

Page Range: 1822-1827

Description:

This study compares results from three different testing methods: Resonant Column, Torsional Simple Shear, and Bender Element tests to determine shear modulus. The resonant column and torsional shear tests were performed on the same hollow cylinder specimen. The bender element test was performed on a triaxial specimen with the same void ratio and confining stress as well as others. Several effects were studied, among them confining stress, shear strain amplitude and for the bender element, anisotropic confinement. Testing methods and data analysis are discussed in the paper because data interpretation is very important in these tests. Results showed that the shear modulus values were almost identical between the resonant column and torsional shear but varied somewhat with the bender element results. Further research will focus on influence of stress anisotropy preparation methods.

Open Access: Yes

DOI: 10.21660/2016.20.39871

Scalable Supervisory Architecture for Autonomous Race Cars

Gergely Bári Péter Bogdán Zalán Demeter Ármin Bogár-Németh

Publication Name: IEEE Intelligent Vehicles Symposium Proceedings

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 264-271

Description:

In recent years, the number and importance of autonomous racing leagues, and consequently the number of studies on them, has been growing. The seamless integration between different series has gained attention due to the scene's diversity. However, the high cost of full scale racing makes it a more accessible development model, to research at smaller form factors and scale up the achieved results. This paper presents a scalable architecture designed for autonomous racing that emphasizes modularity, adaptability to diverse configurations, and the ability to supervise parallel execution of pipelines that allows the use of different dynamic strategies. The system showcased consistent racing performance across different environments, demonstrated through successful participation in two relevant competitions. The results confirm the architecture's scalability and versatility, providing a robust foundation for the development of competitive autonomous racing systems. The successful application in real-world scenarios validates its practical effectiveness and highlights its potential for future advancements in autonomous racing technology.

Open Access: Yes

DOI: 10.1109/IV55156.2024.10588615

Evaluation and improvement of parallel discrete event simulation performance predictions: A rough-set-based approach

László Muka István Derka

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2016-01-01

Volume: 13

Issue: 6

Page Range: 125-145

Description:

Simulation performance prediction methods make possible the realization of performance improvement potentials of Parallel Discrete Event Simulation (PDES) methods, important in the analysis of complex systems and large-scale networks. Currently, high performance execution environments (emerging clusters and computing clouds) advance the development of quality/cost analysis capabilities of performance prediction methods. In this paper, for the evaluation and management of prediction correctness/cost, the efficacy, efficiency and effectiveness coefficients and improvement operations are defined for predictions. The performance coefficients and improvement operations are embedded in the rough-set-modeling and learning process and presented as an enhancement approach of the conventional Coupling Factor Method (CFM). A case study based on the CFM analysis of PDES of a closed queuing network model is presented. In the example, after rough-modeling and train-and-test analysis, the correctness/cost evaluation and effectiveness improvement operations are shown for series of predictions and the feedback connection to modeling refinement phase is demonstrated too.

Open Access: Yes

DOI: DOI not available

Experiments on the influence of oil temperature and pressure on subsynchronous bifurcation and shaft orbit behaviour in automotive turbochargers

Cs Tóth-Nagy Márk Pesthy

Publication Name: Mechanical Systems and Signal Processing

Publication Date: 2026-04-01

Volume: 249

Issue: Unknown

Page Range: Unknown

Description:

This work presents a comprehensive experimental study of the nonlinear dynamic behavior of a high-speed automotive turbocharger rotor system supported by semi-floating bearings. The investigation focuses on how oil supply temperature and pressure influence subsynchronous bifurcation, dynamic instability, and shaft orbit evolution under realistic lubrication environments. Experiments were performed on a dedicated test bench that enabled precise control and monitoring of oil parameters while decoupling rotor dynamics from engine-related disturbances.Shaft-end displacements were measured using dual radial probes, with simultaneous high-frequency vibration and speed tracking. Order spectra and Fourier analysis were conducted at key operational points, and orbit patterns were visualized through whirl plots to capture changes in rotor motion across a full range of speeds. The results reveal that elevated oil temperature markedly lowers the bifurcation threshold, causing nonlinear instabilities—marked by earlier onset of complex, multi-loop orbits—at reduced speeds. These transitions are dominated by two principal subsynchronous spectral components, Sub 1 (cylindrical and conical modes) and Sub 2 (translational and bending modes), whose evolution is mapped in detail using both spectral and orbit-based methods. A distinctive trend toward thermal saturation in the lubrication system was identified, as outlet oil temperature increases plateau at higher inlet temperatures, indicating a thermal energy absorption limit.Comparative analysis demonstrated that the system’s dynamic response is highly sensitive to both viscosity and supply pressure, with higher temperatures and lower viscosities amplifying instability and orbit complexity. Filtered vibration signals provided consistent results with displacement data, validating their use for practical bifurcation detection.By combining advanced order-domain diagnostics with direct orbit visualization, this study establishes clear experimental benchmarks for understanding turbocharger instability mechanisms, justifies the focus on the dominant subsynchronous modes, and highlights the importance of oil rheology and thermal effects in governing rotor dynamics. These insights support the development of improved predictive models and informed maintenance or control strategies for higher efficiency and reliability in turbocharger systems.

Open Access: Yes

DOI: 10.1016/j.ymssp.2026.114088

A new species of Trichochloritis Pilsbry, 1891 from Sichuan, China (Gastropoda: Stylommatophora: Camaenidae)

Barna Páll-Gergely András Hunyadi

Publication Name: Acta Phytopathologica Et Entomologica Hungarica

Publication Date: 2025-11-13

Volume: 60

Issue: 2

Page Range: 155-160

Description:

Trichochloritis kiralyi sp. nov. is described from Sichuan Province, China. This new species is most similar to Trichochloritis adaequata (Gredler, 1894), which has a more elevated spire and a narrower umbilicus. Trichochloritis hunanensis Yen, 1939 is a new synonym of T. adaequata.

Open Access: Yes

DOI: 10.1556/038.2025.00255

We remember Vilmos Schulhof (1874-1944)

Ágota Kulisch Noémi Gyarmati Zsuzsanna Mándó József Horváth Ágota Kránicz Annamária Bergmann Szilvia Boros

Publication Name: Orvosi Hetilap

Publication Date: 2024-11-17

Volume: 165

Issue: 46

Page Range: 1837-1839

Description:

No description provided

Open Access: Yes

DOI: 10.1556/650.2024.HO2805

Some basic questions of measurement and measurement theory

Dusek Tamás

Publication Name: Statisztikai Szemle

Publication Date: 2024-01-01

Volume: 102

Issue: 2

Page Range: 107-157

Description:

Statistical analysis has a special relationship to measurement. For it, measurement and measurement theory not only provide the data on which analysis is based, but are also a source of important uncertainties in theoretical, methodological and applied research. A detailed presentation of measurement issues is therefore justified, together with the different approaches and the arguments behind them. After a careful discussion of the everyday and scientific meanings of measurement, the paper deals with the different meanings and conceptions of measurement, and then turn to the drastic change in meaning in social statistics in the mid-20th century. Then the theory of measurement scales, their criticism and proposals for expansion will be discussed, and finally some of the specific aspects of Likert-type statements that cannot be placed within the framework of measurement scales will be examined. One of the conclusions of the paper is that the Stevens system of measurement scales cannot be regarded as an adequate description of data types.

Open Access: Yes

DOI: 10.20311/stat2024.02.hu0107