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Found 6414 publications

Development of 1D and 3D acoustic simulation methods for transmission loss based on transfer matrix measurement results

Balázs Vehovszky Balázs Kuti Zoltán Gazdagh Attila Schweighardt Miklós Szendrő

Publication Name: Advances in Acoustics Noise and Vibration 2021 Proceedings of the 27th International Congress on Sound and Vibration Icsv 2021

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

During the acoustical characterization of a component of a building, machine or vehicle, the normal incidence sound transmission loss is a major factor. Transmission loss simulation is also crucial in designing intake or exhaust elements, such as reflective mufflers. However, there is not enough information in the open literature about the applicable frequency ranges of experimental and 1- and 3D simulation methods. Therefore, the main purpose of this paper is to evaluate the frequency limits of computational and experimental transmission loss analyses of various reflective mufflers. For the validation two in-house impedance tube test benches were designed and multiple measurement setups were investigated. The combination of the four-pole matrix and the two-load methods was used during the experimental part of the study. In order to obtain appropriate transfer function results, distinct setups were evaluated, such as a low-frequency sound source with bigger tube diameter and a high-frequency sound source with smaller tube diameter. The low-frequency setup is suitable for the investigation of the system in the range of 30-500 Hz. The high-frequency setup is capable of measuring from 300 Hz to 2000 Hz, which is the upper frequency limit of the range of interest. Consequently, the in-house system is suitable for measuring the transmission loss in the 30-2000 Hz frequency range. 1D simulations were performed using Ricardo Wave software and 3D simulations were carried out in the STAR-CCM+ software. The upper cutoff frequency of 1D simulation method was determined to be 1500 Hz according to the correlation with the measurements. The frequency range of simulation could be extended up to 2000 Hz by employing 3D simulation for transmission loss calculations. This paper gives insights into the transmission loss measurements with the in-house system and the correlation analysis with different simulation methods.

Open Access: Yes

DOI: DOI not available

Differences, constraints and key elements of providing local sharing economy services in different-sized cities: A Hungarian case

Katalin Czakó Dávid Fekete Kinga Szabó Marcell Tóth

Publication Name: Resources

Publication Date: 2019-09-01

Volume: 8

Issue: 3

Page Range: Unknown

Description:

The business models of sharing economy services can differ fromeach other in different-sized cities. This paper provides a deeper understanding of the implementation of locally operating services for car, bicycle and office sharing in the urban environment. Our goal is to reveal the differences between the capital city and an economically well-developed city in order to provide beneficial findings to the development of the presently operating services, or to the possible implementation of future services. Methodology of the paper applies the Business Model Canvas approach (BMC). We introduce a comparative analysis using data from the Hungarian database, which records details of all the publicly visible sharing economy services countrywide. The results show that BMC can reflect the main differences, constraints and key elements in the business models of sharing economy services. We can say that, in the case of a bike sharing service operated in the non-capital city, there is more segmentation than seen in the same service in the capital. There are significant price differences, especially in the case of long-term tickets. The number of inhabitants and private capital remain the biggest constraints in the case of car-sharing services, but there is also a possibility of implementation in the non-capital cities by applying small-scale services with a good value proposition and segmentation.

Open Access: Yes

DOI: 10.3390/resources8030147

Synergistic Effects of CuO and ZnO Nanoadditives on Friction and Wear in Automotive Base Oil †

I. Szabó Rafiul Hasan

Publication Name: Applied Sciences Switzerland

Publication Date: 2025-08-01

Volume: 15

Issue: 15

Page Range: Unknown

Description:

Efficient lubrication lowers friction, wear, and energy losses in automotive drivetrain components. Advanced lubricants are key to sustainable transportation performance, durability, and efficiency. This study analyzes the tribological performance of Group III base oil with CuO and ZnO nanoadditive mixtures. These additives enhance the performance of Group III base oils, making them highly relevant for automotive lubricant applications. An Optimol SRV5 tribometer performed ball-on-disk sliding contact tests with 100Cr6 steel specimens subjected to a 50 N force and a temperature of 100 °C. The test settings are designed to mimic the boundary and mixed lubrication regimes commonly seen in the automobile industry. During the tests, the effect of nanoparticles on friction was measured. Microscopic wear analysis was performed on the worn specimens. The results demonstrate that adding 0.3 wt% CuO nanoparticles to Group III base oil achieves a 19% reduction in dynamic friction and a 47% decrease in disk wear volume compared to additive-free oil. Notably, a 2:1 CuO-to-ZnO mixture produced synergy, delivering up to a 27% friction reduction and a 54% decrease in disk wear. The results show the synergistic effect of CuO and ZnO in reducing friction and wear on specimens. This study highlights the potential of nanoparticles for lubricant development and automotive applications.

Open Access: Yes

DOI: 10.3390/app15158258

Experimental confirmation of self-regulating turbulence paradigm in two-dimensional spectral condensation

M. Berta L. Bardóczi L. Schmitz A. Bencze

Publication Name: Physical Review E Statistical Nonlinear and Soft Matter Physics

Publication Date: 2014-12-03

Volume: 90

Issue: 6

Page Range: Unknown

Description:

Turbulent transport in magnetic fusion plasmas can be significantly suppressed by Reynolds-stress-induced zonal flows, allowing effective plasma confinement. We present experimental evidence of spatiotemporal correlation between small-scale turbulence-induced Reynolds stress and large-scale zonal flow production in the E×B driven hydrodynamic spectral condensation. We show that Reynolds stress is generated effectively by anisotropic vorticity structures possessing collective tilt angle. The maximum amplitude of the tilt, the Reynolds stress, and the mean zonal flow production coincide with the transition time of the velocity field, indicating a key role of turbulence-induced Reynolds stress in the condensation of the flow. The analysis of the energy transfer between turbulence and zonal flow shows coherent oscillations with π/2 phase delay, thus indicating a predator-prey-like interaction between zonal flow and turbulence.

Open Access: Yes

DOI: 10.1103/PhysRevE.90.063103

Design, programming and orchestration of heterogeneous manufacturing systems through VR-powered remote collaboration

Tamás Haidegger Peter Galambos Adam B. Csapo István Marcell Fülöp Péter Zentay Imre J. Rudas Peter Baranyi

Publication Name: Robotics and Computer Integrated Manufacturing

Publication Date: 2015-01-01

Volume: 33

Issue: Unknown

Page Range: 68-77

Description:

Modern manufacturing systems are often composed of a variety of highly customized units and specifically designed manufacturing cells. Optimization of assembly and training of staff requires a series of demo installations and excessive use of costly operational resources. In some cases, components are located at different sites, making the orchestration of the whole system even more difficult. Virtual Reality (VR) collaboration environments offer a solution by enabling high fidelity testing and training of complex manufacturing systems. On the other hand, such platforms are difficult to implement in an engineering perspective, as they are required to provide reliable, standard interfaces towards both robotic components and human operators. The VirCA (Virtual Collaboration Arena) platform is a software framework that supports various means of collaboration through the use of 3D augmented/virtual reality as a communication medium. VirCA offers functions for the high-level interoperability of heterogeneous components in a wide range of domains, spanning from research & development, through remote education to orchestration and management of industrial processes in manufacturing applications. This paper provides an overview of the industrial requirements behind high-fidelity virtual collaboration and demonstrates how the VirCA platform meets these requirements. Use cases are provided to illustrate the usability of the platform.

Open Access: Yes

DOI: 10.1016/j.rcim.2014.08.012

Low speed operation of sensorless estimators for induction machines using extended, unscented and cubature kalman filter techniques

Krisztián Horváth Denes Fodor

Publication Name: International Conference on Electical Drives and Power Electronics

Publication Date: 2019-09-01

Volume: 2019-September

Issue: Unknown

Page Range: 279-285

Description:

In this study, three feasible speed sensorless estimators of induction machines are presented by using extended, unscented and cubature Kalman filter algorithms. The estimators are based on an augmented non-linear state-space model of these machines, which describes the dynamics in stationary reference frame with six state variables. As an important part of the estimator design, an observability study is provided for the nonlinear model and an observability condition is formulated as well. The estimators are compared experimentally around zero stator frequency with respect to the speed estimation performance. However, the estimators are investigated only in open-loop and without external load disturbance.

Open Access: Yes

DOI: 10.1109/EDPE.2019.8883936

Preference using Root Value based on Aggregated Normalizations (PROVAN): A data-driven method for socio-economic and innovation assessment

Sanjib Biswas Prasenjit Chatterjee Nibir Khawash Edmundas Kazimieras Zavadskas

Publication Name: Socio Economic Planning Sciences

Publication Date: 2026-02-01

Volume: 103

Issue: Unknown

Page Range: Unknown

Description:

Socio-economic development (SED) remains a critical priority for policymakers aiming to foster inclusive growth and drive national progress. This study presents a comprehensive multi-criteria assessment of regional SED across 16 Indian states, focusing on the influence of innovation (INV) performance and foreign direct investment (FDI) on achieving sustainable development goals (SDGs). A new multi-criteria decision-making (MCDM) method, called Preference using Root Value based on Aggregated Normalisations (PROVAN), is introduced in this paper to enhance decision accuracy by integrating five different normalization techniques. Criteria weights are determined using an extended version of Weights by ENvelope and SLOpe (WENSLO) method, which incorporates multiple normalization strategies to improve robustness. The evaluation considers nine SED and seven INV criteria derived from secondary data sources. The causal relationships are statistically analyzed using Somer's δ test, and the model's reliability is confirmed through comparative and sensitivity analyses. Results reveal that Maharashtra emerges as the top-performing state in both SED (1.5572) and INV (1.5473), followed by Tamil Nadu and Karnataka, indicating strong performance across socio-economic and innovation indicators. The findings highlight significant inter-state disparities and confirm that states with stronger innovation capabilities tend to achieve better socio-economic outcomes. FDI is shown to positively influence sustainable economic development, reinforcing the strategic importance of attracting capital to advance SDGs. The proposed PROVAN-WENSLO framework offers a robust and adaptable tool for regional development planning and policy formulation.

Open Access: Yes

DOI: 10.1016/j.seps.2025.102343

Development of bluetooth mesh core stack using omnet++

László Kajdocsi Andras Dorombozi János Kovacs

Publication Name: Sisy 2019 IEEE 17th International Symposium on Intelligent Systems and Informatics Proceedings

Publication Date: 2019-09-01

Volume: Unknown

Issue: Unknown

Page Range: 23-28

Description:

The evolution of networking technologies is crucial in the 21st century. The greatest challenge for the Industry 4.0 is the spread and generalization of cyber physical production systems which cannot evolve without new networking technologies. One of these research areas is the wireless mesh networking which may offer an accurate, fast, adaptive, self-organizing, self-healing and inexpensive solution in communication. Wireless mesh networking involves some radio technologies, like Wi-Fi, ZigBee, Bluetooth, IQRF, etc. The most widespread and cost effective solution of the above mentioned ones is Bluetooth. Luckily, Bluetooth SIG adopted the first mesh core stack into Bluetooth 5 protocol in 2017, although a newer Bluetooth 5.1 came out since then. In this paper, the development of Bluetooth mesh core stack will be presented using OmNET++ simulation tool.

Open Access: Yes

DOI: 10.1109/SISY47553.2019.9111635

Population genetic parameters and phenotypic trends based on soperformance tests data of native Gidran broodmares

Szabolcs Bene J. Péter Polgár László Rózsa Annamária Simon Dávid Mezőszentgyörgyi Ferenc Szabó

Publication Name: Journal of Central European Agriculture

Publication Date: 2024-01-01

Volume: 25

Issue: 3

Page Range: 620-632

Description:

Body measurement and some conformation data recorded in the national breeding mare performance test of the Hungarian Association of Gidran Horse Breeders were processed. The initial database contained the data of the entire Hungarian active (living) breeding mare stock (N = 293), which were born between 1994-2016 and were offspring of 44 breeding stallions. During the study, eight traits-height at withers measured with stick and tape (HWS, HWT), chest girth (CHG), cannon circumference (left fore/front) (CAC), pedigree score (PES), conformation score (COS), movement score (MOS), total score (TOS)-were evaluated. One-and multi-trait analysis of variance (GLM) and weighted linear regression analysis were used to process the data. The corrected mean values (± SE) of the examined traits were as follows: HWS 161.6 ± 0.4 cm, HWT 169.6 ± 0.5 cm, CHG 188.4 ± 0.7 cm, CAC 19.9 ± 0.1 cm, PES 29.1 ± 0.3 points, COS 72.8 ± 0.5 points, MOS 40.5 ± 0.4 points, TOS 142.4 ± 0.7 points. The heritability of HWS, HWT, COS and TOS was moderate and high (0.37-0.47), CHG and CAC proved to be moderate (0.29-0.31), while low h2 values were estimated for MOS (0.20). In the case of body measurements, moderate, decreasing trends (b =-0.25,-0.33,-0.35 and-0.08 cm/year, respectively; P < 0.01), for the other traits while stagnant (NS) phenotypic trends were observed. It can be concluded that the average body measurements as well as the results of the other examined traits for the Gidran breeding mares did not change essentially over time.

Open Access: Yes

DOI: 10.5513/JCEA01/25.3.4235