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Found 6374 publications

Do economic achievements and environmental consequences coincide? The case of cyclicity

Leonid Melnyk Oleksandr Kubatko Volodymyr Lyubchak Natalia Barchenko Péter Németh Volodymyr Lyubchak

Publication Name: Environmental Economics

Publication Date: 2025-01-01

Volume: 16

Issue: 4

Page Range: 134-153

Description:

The significance of green economic growth opens up a new space for studying cyclical development processes, raising the issue of coexistence between sustainable development and the cyclical features of economic growth. The purpose of this study is to identify statistically significant relationships between cyclical components (fluctuations) of economic growth and environmental consequences within national economic systems. The paper utilizes Hodrick–Prescott and Butterworth bandpass filters to detrend dynamic series of ecological and economic development, highlighting cyclical components (fluctuations) that are analyzed for the presence of correlation in the referenced and lag periods (to identify procyclical and lag dynamics). The analysis uses statistical data from the World Bank for Ukraine and Hungary for 1991–2022. The results prove that for Ukraine with an increase in the cyclical component of GDP per capita there is a cyclical increase in pollution indicators, according to the Butterworth filter for NOx emissions from industrial combustion (correlation coefficient 0.72), F-gases emissions from industrial processes (correlation coefficient 0.77), CO2 emissions excluding LULUCF (correlation coefficient 0.70). The situation with Hungary is different, and the business cycle is not correlated with pollution fluctuations. The paper does not find a statistically significant relationship between the business cycle and fluctuations in methane (CH4) emissions from waste (Mt CO2e). Overall, most economic and environmental components are procyclical in nature, with the strongest correlation in the reference period for a developing industrial economy (Ukraine). In contrast, there is no such link within a more developed economy (Hungary).

Open Access: Yes

DOI: 10.21511/EE.16(4).2025.10

Examining Lean Management Principles in SMEs Through Empirical Data Analysis and Systematic Review †

László Buics Eszter Sós Abishae Noel

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

While Lean methodologies have been widely adopted in large enterprises, their application in small and medium enterprises remains an area requiring further exploration. This study aims at a hybrid approach combining a systematic literature review based on the PEO framework and PRISMA methodology with comprehensive data analysis from 780 respondents to examine the direct relation between Lean and SMEs. Various statistical methods were used to identify different patterns and themes. The findings suggest that while resource constraints pose significant challenges for SMEs in adopting Lean, tailored approaches with a significant reliance on leadership commitment can considerably enhance operational efficiency, resilience, costs, and waste reduction. Insights from the analysis further revealed a preference for operational methods with limited adoption of complex and strategic methods of Lean across SMEs. The paper concludes with practical recommendations for SMEs and lays a foundation for future directions in terms of integration with ESG and sustainability.

Open Access: Yes

DOI: 10.3390/engproc2025113054

Temporal dynamics of geopolitical risk: An empirical study on energy commodity interest-adjusted spreads

Brian Lucey Amar Rao Satish Kumar

Publication Name: Energy Economics

Publication Date: 2025-01-01

Volume: 141

Issue: Unknown

Page Range: Unknown

Description:

The functioning of energy markets is essential for global stability and is heavily influenced by geopolitical risks. Understanding these risks is critical for policymakers, market analysts, and nations. This study investigates the impact of geopolitical risks and their components on the futures markets of WTI crude oil and natural gas, utilizing time and frequency connectedness analysis along with impulse response function methods. The analysis is based on a dataset comprising daily prices of spot and futures contracts (across various maturities) as well as treasury yields. Our findings reveal that geopolitical risks have a significant, negative impact on the interest-adjusted spread of WTI crude oil. In contrast, the interest-adjusted spread of natural gas futures (NGF) displays a more complex pattern: while short-term maturities show an insignificant response, long-term maturities exhibit a significant reaction. Spillover effects are more pronounced in the short term but tend to weaken over longer horizons. This study underscores the dynamic influence of geopolitical risks on both key energy markets. Its findings offer a practical framework for risk management, equipping market participants and policymakers with valuable insights to better understand and respond to geopolitical risks in the energy sector.

Open Access: Yes

DOI: 10.1016/j.eneco.2024.108066

IP Packet Forwarding Performance Comparison of the FD.io VPP and the Linux Kernel

Melinda Kosák Gábor Lencse

Publication Name: Infocommunications Journal

Publication Date: 2025-01-01

Volume: 17

Issue: 2

Page Range: 35-44

Description:

There are numerous free software solutions for IPv4 or IPv6 packet forwarding. The Fast Data Project / Vector Packet Processing (FD.io VPP) is a novel and prominent solution. This paper investigates its performance and scalability compared to that of the Linux kernel. The investigation was conducted in accordance with the requirements outlined in the relevant Request for Comments (RFC) documents (RFC 2544, RFC 4814, and RFC 5180) using the siitperf measurement software. Two different test environments were used to eliminate the potential hardware-specific side effects and to gain insight into the performance and scalability of the IPv4 and IPv6 packet forwarding capability of the two investigated solutions. It was found that FD.io VPP outperformed the Linux kernel by approximately an order of magnitude. The configuration of FD.io VPP, along with the details of the measurements, are provided, and the results are presented and analyzed in the paper.

Open Access: Yes

DOI: 10.36244/ICJ.2025.2.5

Evaluation of Indirect Storage Location Systems by Fuzzy Signature

Tamás Hartványi Zoltan Andras Nagy Miklós Szabó

Publication Name: Chemical Engineering Transactions

Publication Date: 2025-01-01

Volume: 121

Issue: Unknown

Page Range: 115-120

Description:

Traditional storage systems often rely on direct access storage locations, but these solutions can be inefficient and environmentally exhausting due to higher energy consumption and limited scalability. In previous studies, we demonstrated that higher efficiency could be achieved with indirectly-accessible storage systems compared to fully directly accessible ones. To compare the different layouts, we developed a simulation model through which warehouse operations were executed. The resulting time values became comparable, allowing us to rank the solutions. However, the conventional method of calculating simple averages, often applied in the evaluation of logistic performance, has limited capacity to capture the complexity of data distributions and the small differences between individual observations. The aim of this study is to interpret warehouse operations from a new perspective using a fuzzy logic-based model, explicitly addressing the research gap that traditional statistical averages cannot adequately capture subtle performance differences. The novelty of our contribution lies in applying fuzzy signatures to warehouse simulation, which enables more precise differentiation between competing system layouts. During the simulation analysis, traditional average values are compared using a classification method based on fuzzy sets, demonstrating that this new approach is more sensitive to performance fluctuations and better reflects real operational conditions. This approach supports the selection of the most suitable storage system for warehouse operations, the initial placement of products, or the operational process that best aligns with emerging demands, enabling greater energy savings and enhancing the overall sustainability of the system.

Open Access: Yes

DOI: 10.3303/CET25121020

Verilog-A Implementation of a Nonlinear Permanent Magnet Synchronous Machine Model for Sensorless Polarity Detection

Istvan Szalay Ferenc Péter Speiser Denes Fodor

Publication Name: Edpe 2025 37th International Conference on Electrical Drives and Power Electronics and 12th Joint Croatia Slovakia Conference

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In this paper, we present the implementation process of a novel extended PMSM model in Verilog-A. The extended PMSM model is based on a quadratic flux-current function that describes the machine's rotor position-dependent and polaritydependent characteristics, enabling the development of signal injection-based sensorless polarity detection algorithms. The Verilog-A module was compiled using OpenVAF, simulated with Ngspice, and integrated via the Qucs-S frontend. Validation was carried out through comparison of simulations and corresponding measurements of non-modulated square-wave and modulated sinusoidal signal injection, two commonly used carrier signals in sensorless control. Simulation results showed good agreement with measurements. The implemented PMSM model is open source. The code and related data are available on GitHub.

Open Access: Yes

DOI: 10.1109/EDPE66853.2025.11224147

Analytical Overview of Accident Emergencies Arising from the Structure and Characteristics of Various Alternative Fuel Vehicles †

I. Lakatos Lea Pődör

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

The spread of alternative fuel vehicles (AFVs) poses new technological and legal challenges. While these vehicles contribute to sustainable transport, their specific operational characteristics require specific regulation and infrastructure. The study analyses the risks associated with AFVs, in particular with regard to occupational safety and operation, and the extent to which the current legal framework in Hungary is able to address these challenges. It also examines the integration of AFVs into the existing transport and service network and makes recommendations for improving regulation, training and infrastructure. The study aims to contribute to enhancing road safety and legal clarity by showing that the safe integration of AFVs requires the modernisation of regulation and the adaptation of technical protocols.

Open Access: Yes

DOI: 10.3390/engproc2025113070

THE IMPACT OF HEALTHY LIFESTYLE APPS' QUALITY ON SATISFACTION AND PERCEIVED IMPACT USING PLS SEM

Ida Ercsey Veronika Keller

Publication Name: Vezetestudomany

Publication Date: 2025-01-01

Volume: 56

Issue: 5

Page Range: 57-71

Description:

Lifestyle and wellbeing (LS) apps represent a popular form of m-health apps that facilitate the maintenance and improvement of health by encouraging active lifestyles. This study aims to adapt the uMARS scale, developed for evaluating the quality of m-health applications, and to investigate the relationship between quality, satisfaction, and behaviour factors in LS applications. Data collection was conducted using a survey in autumn 2023, with a sample size of 157 respondents. The PLS-SEM method was employed to test the hypotheses. The results indicate that four qualitative dimensions of LS apps have a direct impact on overall satisfaction. The qualitative dimensions of LS apps, including functionality, information content and aesthetics, directly impact users’ perceived health-related knowledge, attitudes and behaviour. Furthermore, the quality dimensions indirectly influence users’ perceived health-related factors through satisfaction.

Open Access: Yes

DOI: 10.14267/VEZTUD.2025.05.05

Use of Hybrid Flame Retardants in Chemically Foamed rPET Blends

András Kovács V. A. Szabó Sándor K. Jakab Tamara Zsuzsanna Böcz Gabor Dogossy

Publication Name: Crystals

Publication Date: 2025-01-01

Volume: 15

Issue: 1

Page Range: Unknown

Description:

The foamed structure of recycled polyethylene-terephthalate (rPET) is a promising solution for industrial applications; however, the remedy for its inherent melt-dripping property is still a challenging topic. In our research, we were able to improve the flame retardancy of the endothermic–exothermic hybrid rPET foam by adding a different mixture of flame retardants to the formula. Three different kinds of halogen-free flame retardant agents were used: ammonium polyphosphate-based Exolit AP 422 (AP), organic aluminum phosphate in the form of Exolit OP 1240 (OP), and Budit 342 containing melamine polyphosphate (MPP). The hybrid flame retardant mixture, by combining the swelling and charring mechanism, increased the flame retardancy of the samples. The sample made with 15 phr OP and 5 phr MPP displayed outstanding performance, where five samples were capable of self-extinguishing in 5 s, while only slightly decreasing the tensile and flexural strength properties and simultaneously increasing the Young and flexural modulus compared to the reference sample. The addition of MPP reduced the porosity in many cases, while preventing cell coalescence. Our results prove that the hybrid flame retardant agent frameworks efficiently increase the flame retardancy of rPET foams, facilitating their application in industrial sectors such as the aerospace, packaging, renewable energy, and automotive industries to realize sustainability goals. The utilization of halogen-free flame retardants is beneficial for better air quality, reducing toxic gas and smoke emissions.

Open Access: Yes

DOI: 10.3390/cryst15010080