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Found 6674 publications

Estimation of Thermodynamic and Emission Characteristics of a Sustainable Hydrogen-Gasoline Engine Through Simulation

A. L. Nagy Péter Németh György Marton Barna Hanula

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2025-01-01

Volume: 1345 LNNS

Issue: Unknown

Page Range: 21-32

Description:

Hydrogen is expected to play a significant role in mobility and transportation as a form of energy source. To assess the effects of hydrogen as a gradual replacement fuel for internal combustion engines, a preliminary 1D thermodynamic simulation was carried out using AVL Boost for 0 vol%, 4 vol% and 8 vol% hydrogen content. Calculations were based on independently published research results, and focused on peak firing temperature (PFT), brake specific fuel consumption (BSFC), nitrous oxide emission (NOx), and carbon monoxide (CO) emission values. Results showed a decrease in BSFC of up to 3 g/kWh and ca. 5 mg/kWh decrease in CO emission with 8 vol% hydrogen, but also highlight an increase of PFT by 14 K, and ca. 0.5 g/kWh additional NOx production at high loads.

Open Access: Yes

DOI: 10.1007/978-3-031-87620-2_3

A review of elasto-plastic shakedown analysis with limited plastic deformations and displacements

R. M. Movahedi

Publication Name: Periodica Polytechnica Civil Engineering

Publication Date: 2018-05-22

Volume: 62

Issue: 3

Page Range: Unknown

Description:

In classical plasticity the shakedown analysis is among the most important basic problems. The principles of shakedown analysis are counterparts to those of limit analysis in the sense that they provide static and kinematic approaches to the question of whether or not shakedown will occur for a body under multiple variable loading conditions. The principles of limit analysis provide static and kinematic approaches to the question of whether or not the plastic limit state will be reached by a body under proportional loading. The principles of shakedown analysis are, however, considerably more difficult to apply than those of limit analysis. In spite of these difficulties, shakedown analysis is a vital and developing topic in plasticity and a great number of applications have been made. At the application of the plastic analysis and design methods the control of the plastic behaviour of the structures is an important requirement. Since the shakedown analysis provide no information about the magnitude of the plastic deformations and residual displacements accumulated before the adaptation of the structure, therefore for their determination bounding theorems and approximate methods have been proposed.

Open Access: Yes

DOI: 10.3311/PPci.11696

Cooperative learning in VR environment

Viktoria Kovecses-Gosi

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2018-01-01

Volume: 15

Issue: 3

Page Range: 205-224

Description:

Nowadays it is increasingly visible that a change in the approach is needed in the field of education, thus we should move from “traditional” educational methods towards experience-oriented and cooperative teamwork-based education which considers the characteristics of the digital generation. After the brief demonstration of the methodological characteristics and the principles of digital culture, the present study aims to introduce how a lesson built on the improvement of different intelligence levels through cooperative techniques can be implemented with the help of virtual space, what opportunities are provided by the MaxWhere program for planning and organising teamwork and for supporting learning.

Open Access: Yes

DOI: 10.12700/APH.15.3.2018.3.12

THE RELATIONSHIP BETWEEN CORPORATE SOCIAL RESPONSIBILITY AND FINANCIAL PERFORMANCE IN THE PRACTICES OF CONVENTIONAL AND ISLAMIC COMMERCIAL BANKS IN THE PAKISTANI BANKING SYSTEM

Csaba Lentner Yahya Khan Szegedi Krisztina Tatay Tibor

Publication Name: Vezetestudomany

Publication Date: 2024-03-14

Volume: 55

Issue: 3

Page Range: 44-57

Description:

The authors’ study explored the incorporation of the CSR concept followed by Western banks into the practice of Islamic-based dual banking. Their empirical research covered the listed commercial banks in Pakistan. They studied the CSR activities and their disclosure in reports of listed commercial banks in Pakistan during the period 2008–2018 and how they affected the financial performance of the banks. The results of the study revealed that the disclosure of CSR increased by an average of 15 percentage during the period under study: from 56.48% to 71.06%. The results of the study confirm that banks that consciously engage in CSR activities and communicate this appropriately achieve better financial performance. However, disclosure of CSR information has no significant impact on the market valuation of listed banks, as measured by Tobin’s Q ratio.

Open Access: Yes

DOI: 10.14267/VEZTUD.2024.03.04

THE IMPACT OF COVID-19 AND THE RUSSIAN-UKRAINIAN CONFLICT ON THE ORGANISATIONS STUDIED

Arnold Tóth Kőműves Zsolt Módosné Szalai Szilvia Kálmán Botond Szabó Szentgróti Gábor Dajnoki Krisztina Pató Gáborné Szűcs Beáta Poór József Walter Virág

Publication Name: Vezetestudomany

Publication Date: 2024-03-14

Volume: 55

Issue: 3

Page Range: 14-28

Description:

In the last three years, the way the world works has changed more than in all the previous decades combined. The changes in market processes and systems have clearly been driven by two dominant phenomena: the pandemic crisis caused by COVID-19 and the Russian-Ukrainian conflict. These two world events have changed fundamental norms, which has forced organisations to change their strategies. The question is: what are the organisations in question really planning? What is influencing their reactions? The aim of the authors’ publication is to show how organisations were thinking in the early stages of the two crises, and whether they are able to assess the expected impact and plan the appropriate measures. Their empirical research found that micro-enterprises tend to project their pessimism on the whole economy. Also, their services are less dependent on supply chain resilience. Furthermore, their various war-induced measures were related to their past external relations.

Open Access: Yes

DOI: 10.14267/VEZTUD.2024.03.02

Vulnerability assessment of residential buildings in Jeddah: A methodological proposal

Orsolya Kegyes-Brassai Ahmed Al-ghamadi Md Faiz Shah Anas Ahmed Anas Ahmed Richard P. Ray

Publication Name: International Journal of Geomate

Publication Date: 2018-01-01

Volume: 14

Issue: 44

Page Range: 134-141

Description:

The City of Jeddah in Saudi Arabia is expanding rapidly, in terms of new buildings and increasing population. The rapid urbanization leads to higher risk from seismic events; even in areas of moderate seismicity such as this city. The present study addresses the rapid evaluation of a large number of buildings in Jeddah involving steps to determine hazard, assessing building stock, and computing vulnerability with a scoring method from FEMA 155. Two districts were selected for investigation based on a cluster analysis applied to population and building data from the local municipality. One selected district was a contemporary developed urbanized area, and the other was a more traditional area. Such selection offered the possibility to compare vulnerability of buildings built according to different seismic codes and to make assumptions about the rest of the city based on typical structures of districts. The basic structural score was determined considering the building structure and moderate seismicity of the region using score modifiers, e.g. vertical irregularity score modifier; soil score modifier assuming sabkahs. The results of the investigation reveal a different level of vulnerability and areas where intervention is needed. The method can be applied for further analysis of the city.

Open Access: Yes

DOI: 10.21660/2018.44.85087

Energy management and hybrid energy storage in metro railcar

István Szénásy

Publication Name: 2012 International Conference on Renewable Energy Research and Applications Icrera 2012

Publication Date: 2012-12-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

This paper focuses on the use of modeling and simulation one of renewable energy. © 2012 IEEE.

Open Access: Yes

DOI: 10.1109/ICRERA.2012.6477423

Validation of a Fuzzy Wind Resistance Risk Index for UAV Energy Consumption Using Telemetry Data †

László Kajdocsi Szabolcs Kocsis Szurke Szabolcs Kocsis Szürke

Publication Name: Engineering Proceedings

Publication Date: 2025-01-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

Unmanned aerial vehicles have become essential tools in a wide range of applications. As drone operations grow more complex, the accurate prediction of battery runtime and aerodynamic flight safety risks, particularly those caused by wind, becomes increasingly important. This study employs the Wind Resistance Risk Index (WRRI), to quantify the impact of wind conditions on UAV performance. While several predictive models have been introduced to address these issues, many have not been thoroughly validated under real operational conditions. This study focuses on the post-validation of a previously developed fuzzy-based predictive model, using telemetry data collected from four UAV missions. Key flights and battery parameters were analyzed. The results demonstrate that real-world flight data provide valuable insight into model reliability and highlight discrepancies that can guide future model refinement. This work contributes to enhancing UAV safety by bridging the gap between theoretical predictions and empirical evaluations, specifically under varying wind conditions.

Open Access: Yes

DOI: 10.3390/engproc2025113028

Wild Blackberry Fruit (Rubus fruticosus L.) as Potential Functional Ingredient in Food: Ultrasound-Assisted Extraction Optimization, Ripening Period Evaluation, Application in Muffin, and Consumer Acceptance

E. Lakatos Rita Székelyhidi Beatrix Sik Zsolt Ajtony

Publication Name: Foods

Publication Date: 2024-03-01

Volume: 13

Issue: 5

Page Range: Unknown

Description:

The aim of the present study is to evaluate the antioxidant properties of wild blackberry fruits as well as their possible use in powdered form as a functional ingredient. For this, ultrasound-assisted extraction optimization, ripening stage evaluation, and wild blackberry powder incorporation into a real food matrix were applied. The optimum conditions for extraction were as follows: 60% MeOH, 20 min of extraction time, acidification with 0.5% HCl, and a 1:40 g/mL solid-to-solvent ratio, which allowed the following yields: total polyphenol content (TPC): 53.8 mg GAE/g; total flavonoid content (TFC): 5.78 mg QE/g; total monomer anthocyanin content (TMA): 11.2 mg CGE/g; 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH): 71.5 mg AAE/g; IC50: 52.3 µg/mL. The study also highlighted that, during the ripening process, the TPC (41.4%), TFC (17.0%), and DPPH levels (66.4%) of the fruits decreased while the TMA yield increased. The incorporation of blackberry powder at different levels (5–20%) increased the TPC, TFC, TMA, and antioxidant properties of muffins. Although the muffins enriched with 20% wild blackberry powder had the best chemical properties (TPC: 3.15 mg GAE/g; TFC: 0.52 mg QE/g; TMA: 0.23 mg CGE/g; DPPH: 1.70 mg AAE/g; IC50: 1.65 mg/mL), the sensory analysis showed that the addition of blackberry fruit at a concentration of 10% to the muffins resulted in the best consumer acceptability.

Open Access: Yes

DOI: 10.3390/foods13050666