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Publications - 6278

Optimal protocols for quantum quenches of finite duration in the Luttinger model

Masudul Haque Ádám Bácsi Balázs Dóra Balázs Dóra

Publication Name: Physical Review B

Publication Date: 2019-06-06

Volume: 99

Issue: 24

Page Range: Unknown

Description:

Reaching a target quantum state from an initial state within a finite temporal window is a challenging problem due to nonadiabaticity. We study the optimal protocol for switching on interactions to reach the ground state of a weakly interacting Luttinger liquid within a finite time τ, starting from the noninteracting ground state. The protocol is optimized by minimizing the excess energy at the end of the quench, or by maximizing the overlap with the interacting ground state. We find that the optimal protocol is symmetric with respect to τ/2, and can be expressed as a functional of the occupation numbers of the bosonic modes in the final state. For short quench durations, the optimal protocol exhibits fast oscillation and excites high-energy modes. In the limit of large τ, minimizing energy requires a smooth protocol while maximizing overlap requires a linear quench protocol. In this limit, the minimal energy and maximal overlap are both universal functions of the system size and the duration of the protocol.

Open Access: Yes

DOI: 10.1103/PhysRevB.99.245110

Surface Activation of Polyamide 6 Nanocomposites by Atmospheric Plasma: Wettability and Chemical Changes for Type IV Pressure Vessel Liners

Eszter Kókai Dávid István Kis

Publication Name: International Journal of Automotive Science and Technology

Publication Date: 2025-01-01

Volume: 9

Issue: 1st Future of Vehicles Conf.

Page Range: 41-46

Description:

This study explores how atmospheric-pressure plasma treatments can modify the surface properties of polyamide 6 (PA6) and its nanocomposites reinforced with organomodified montmorillonite (OMMT), materials developed as potential liners for Type IV composite overwrapped pressure vessels (COPVs) designed for hydrogen storage. Four material compositions were examined: neat PA6 and composites containing 1, 2.5, 5, and 10 wt.% OMMT. Two different plasma systems—a piezoelectric plasma brush and a rotary plasma source—were used to activate the surfaces, and their effects were evaluated using water contact angle (WCA) measurements and Fourier transform infrared spectroscopy (FTIR). Both plasma treatments effectively increased the wettability of the tested materials, but the rotary plasma consistently produced the lowest WCA values across all compositions, reaching as low as 21° for neat PA6. These findings suggest that the rotary plasma’s higher power and dynamic exposure enhance the formation of polar functional groups and may increase micro-scale roughness, leading to improved surface activation. FTIR results confirmed the appearance and growth of oxidized functional groups, particularly carbonyl and hydroxyl species, which are linked to the increased surface polarity and hydrophilicity. Time-dependent contact angle tests revealed that the effects of plasma treatment were not permanent. Over several hours, the contact angles gradually increased, returning close to untreated values.

Open Access: Yes

DOI: 10.30939/ijastech..1753231

CSR and workplace autonomy as enablers of workplace innovation in SMEs through employees: Extending the boundary conditions of self-determination theory

Laszlo Vasa Susana Álvarez-Otero Jacob Cherian Ubaldo Comite Muhammad Safdar Sial Beili Li Xu Fan Muhammad Safdar Sial

Publication Name: Sustainability Switzerland

Publication Date: 2021-06-01

Volume: 13

Issue: 11

Page Range: Unknown

Description:

The current business environment characterized by high uncertainty, volatility, and stiff situation of competitiveness that is evident in almost every sector has increased the importance of workplace innovation for contemporary businesses. In this regard, a considerable attention in realizing employees of an organization as a source of innovation is not evident from the existing literature. In this aspect, the current study is an attempt to foster workplace innovation through employees in the SME sector of an emerging economy. In doing so, the authors propose that corporate social responsibility (CSR) initiatives of an SME, along with workplace autonomy, are helpful in creating an environment at the workplace that fosters innovative employee behavior (IEB). Furthermore, the current study also extends the boundary condition of the theory of self-determination by arguing that this theory provides a comprehensive framework to explain employees’ motivation for workplace innovation. The data of the current survey was obtained from the SME sector situated in two large cities of a developing country through a self-administered questionnaire which was then analyzed through structural-equation-modeling (SEM) using the AMOS software. The results confirmed that CSR directly relates to IEB and workplace autonomy mediates this relationship. The study also discusses the implications of this survey for theory and practice.

Open Access: Yes

DOI: 10.3390/su13116104

Using Multivariate Statistical Analysis for Examining the Relationship between Food Waste Generation and Socio-economic Factors

A. Zseni András Horváth Gergely Zoltán Macher Dóra Sipos Judit Pécsinger

Publication Name: Journal of Sustainable Development of Energy Water and Environment Systems

Publication Date: 2025-09-01

Volume: 13

Issue: 3

Page Range: 1-16

Description:

Food waste contributes to social inequalities and sustainability issues by worsening resource overuse and environmental harm. The United Nations Sustainable Development Goal 17 highlights the importance of reducing food waste to address hunger and promote a sustainable, economically viable global food system. This paper examines the geographic differences in food waste levels among European Union member nations and analyses the associations between food waste and diverse environmental, geographic, social and economic indicators, including Sustainable Development Goals and other sustainability metrics. Using dimensionality reduction methods, nontrivial multivariate connections between food waste and these parameters were identified, allowing for the characterisation of countries based on a few significant factors. Principal Component Analysis (PCA), applied to food waste data across European Union countries, uncovered three distinct groups: (1) those with elevated food waste in primary production, manufacturing and distribution stages; (2) those with lower waste in these domains yet elevated waste in restaurants and households; and (3) those with all of their food waste components smaller than or equal to the average. The multivariate linear correlation between the PCA factors and socio-economic parameters is nonsignificant, but a few (nonlinear) regularities could be identified: five of the six countries of the first group above are characterised by the population settled mainly on flatland and an above-average supply of meat or fish. Another pattern observed is that former Eastern Bloc countries belong to the third group. The research findings offer valuable insights that can inform the efforts of environmental experts, professionals and policymakers working in the circular economy and waste management domains. This knowledge can facilitate the development of more effective strategies aimed at mitigating food waste and promoting sustainability.

Open Access: Yes

DOI: 10.13044/j.sdewes.d13.0579

Multi-Stage Centralized Energy Management for Interconnected Microgrids: Hybrid Forecasting, Climate-Resilient, and Sustainable Optimization

Mona Gafar Mohamed Kouki Nahid Osman Ragab A. El-Sehiemy

Publication Name: CMES Computer Modeling in Engineering and Sciences

Publication Date: 2025-01-01

Volume: 145

Issue: 3

Page Range: 3783-3811

Description:

The growing integration of nondispatchable renewable energy sources (PV, wind) and the need to cut CO2 emissions make energy management crucial. Microgrids provide a framework for RES integration but face challenges from intermittency, fluctuating loads, cost optimization, and uncertainty in real-time balancing. Accurate short-term forecasting of solar generation and demand is vital for reliable and sustainable operation. While stochastic and machine learning methods are used, they struggle with limited data, complex temporal patterns, and scalability. Key challenges include capturing seasonal to weekly variations and modeling sudden fluctuations in generation and consumption. To address these issues, this paper presents a novel three-stage centralized EMS for interconnected microgrids. The first stage involves comprehensive data analysis to extract meaningful patterns. The second stage introduces a hybrid forecasting framework that integrates stochastic (Prophet) with machine learning (BiLSTM) techniques to improve prediction accuracy under uncertainty. In the third stage, a modified linear programming approach leverages the improved short-term forecasts to optimize energy sharing between microgrids, with the aim of reducing operational costs, minimizing carbon emissions, and improving system stability under climate variability. The proposed EMS is designed to accommodate diverse microgrid configurations while maintaining computational efficiency. Four scenarios are considered to evaluate the proposed energy management strategy. The obtained results demonstrate that the proposed EMS significantly improves both forecasting accuracy and operational performance. The combined methods achieve the best performance among all tested models, with an RMSE of 0.0070, MAE of 0.0043, and R2 of 0.9988, corresponding to improvements of ΔRMSE = −0.2122 and ΔR2 = +0.7126 relative to Prophet. These substantial gains in predictive accuracy translate into more precise battery scheduling, reduced grid dependency, and optimized power dispatching, thereby significantly enhancing system efficiency, reliability, and sustainability. Overall, the results highlight the effectiveness of integrating hybrid forecasting with optimization-based EMS, providing a viable pathway toward high penetration of renewable energy sources in future power systems.

Open Access: Yes

DOI: 10.32604/cmes.2025.071964

A long-distance runner in the colours of two clubs. Kálmán Kulcsár is eighty

Károly Varga

Publication Name: Tarsadalomkutatas

Publication Date: 2008-01-01

Volume: 26

Issue: 2

Page Range: 131-141

Description:

We greet a scholar, politician and researcher of major format on the occasion of his eightieth birthday. During his life full of work Kálmán Kulcsár has introduced new disciplines in Hungary, as a science politician he made major efforts for the establishment and consolidation of the institutions of sociology and political science. As a professor he taught the theory of the state and of law, and the sociology of law to generations, as a politician and Minister of Justice he did a great deal for the legal preparation of the change of the political system. As a diplomat he represented our country in Ottawa to the satisfaction of all. Above all he is an extremely prolific researcher who publishes his interesting writings to this day. His interest extends over theoretical questions to the development of individual societies, from Europe to Asia, his profundity is legendary; his clear-cut style makes his writings enjoyable to the reader. We hope that he would surprise his associates, disciples and the Hungarian academic life with several new works to come. © 2008, Akadémiaí Kiadó.

Open Access: Yes

DOI: 10.1556/Tarskut.26.2008.2.1

Literature Review of the Behaviour of Adhesive Joint Fatigue Performance

Zoltán Weltsch Miklós Berczeli Péter Péczi-Kovács

Publication Name: Materials Science Forum

Publication Date: 2025-01-01

Volume: 1153

Issue: Unknown

Page Range: 23-32

Description:

Adhesive joints are essential in modern engineering, offering lightweight, durable and efficient solutions for bonding in industries such as aerospace, automotive, and renewable energy. However, their fatigue performance under cyclic loading remains a critical challenge, shaped by a complex interplay of geometrical, material, environmental, and loading factors. This review explores the mechanisms of fatigue failure, highlighting the importance of joint design, material optimization, and surface preparation in mitigating stress concentrations and enhancing durability. Advances in toughened adhesives, surface treatments, and environmental protection methods are highlighted, along with predictive models ranging from empirical S-N curves to advanced finite element simulations and probabilistic approaches. Despite significant progress, challenges remain in integrating these techniques for real-world applications, particularly under variable loading and harsh environmental conditions. Future research must focus on hybrid methodologies, adaptive materials, and standardized protocols to bridge the gap between laboratory insights and practical implementations. This comprehensive review provides a foundation for improving the fatigue performance of adhesive joints, ensuring their reliability and effectiveness in critical engineering systems.

Open Access: Yes

DOI: 10.4028/p-F2MUdc

Classification of plantar foot alterations by fuzzy cognitive maps against multi-layer perceptron neural network

Miklós F. Hatwágner Antonio Hernandez-Zavala Silvia L. Chaparro-Cardenas Julian Andres Ramirez-Bautista László T. Kóczy Jorge A. Huerta-Ruelas

Publication Name: Biocybernetics and Biomedical Engineering

Publication Date: 2020-01-01

Volume: 40

Issue: 1

Page Range: 404-414

Description:

Load distribution analysis on foot surface allows knowing human mechanical behavior and aids the doctor in the detection of gait disorders like, the risk of foot ulcerations, leg discrepancy, and footprint alterations. Plantar pressure data combined with techniques that use integral reasoning produce easy understanding medical tools for assisting in treatment, early detection, and the development of preventive strategies. The present research compares the classification of human plantar foot alterations using Fuzzy Cognitive Maps (FCM) trained by Genetic Algorithm (GA) against a Multi-Layer Perceptron Neural Network (MLPNN). One hundred and fifty-one subject volunteers (aged 7–77) were classified previously with the flat foot (n = 70) and cavus foot (n = 81) by specialized physicians of the Piédica diagnostic center. The trial walking was conducted using plantar pressure platforms FreeMed®. The foot surface was divided into 14 areas that included toe 1 st to 5th, metatarsal joint 1st to 5th, lateral midfoot, medial midfoot, lateral heel, and medial heel. Pressure data were normalized for each area. Better performance in the classification using small amounts of data were found by using Fuzzy rather than non-Fuzzy approach.

Open Access: Yes

DOI: 10.1016/j.bbe.2019.12.008

On the topology of two dimensional generalized cell systems

Ibolya Zsoldos J. Janik Tamás Réti

Publication Name: Recent Advances in Multidisciplinary Applied Physics

Publication Date: 2005-12-01

Volume: Unknown

Issue: Unknown

Page Range: 559-564

Description:

No description provided

Open Access: Yes

DOI: 10.1016/B978-008044648-6.50085-9