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Publications - 6383

Two-phase heat transfer modelling and coupled design approach for optimization and stability analysis of vertical thermosyphon reboilers

Zekun Yang Guanghui Li Ting Pan Xinyang Ma Nan Zhang

Publication Name: Applied Thermal Engineering

Publication Date: 2026-03-01

Volume: 288

Issue: Unknown

Page Range: Unknown

Description:

Vertical thermosyphon reboilers (VTRs) are widely used in distillation due to their high heat transfer efficiency and low fouling tendency. However, conventional design approaches and commercial tools often treat two-phase heat transfer, geometry, and pressure balance in isolation and depend on extensive manual tuning, which may yield low solution quality. To address this gap, a rigorous mixed integer nonlinear programming (MINLP) optimization framework is established for VTR design that couples thermodynamic, hydraulic, and geometric decisions simultaneously. A two-stage heat transfer modelling approach is proposed to capture the convective boiling transition by integrating sensible heating and boiling heat transfer mechanisms. Within this approach, a dynamic switching scheme selects heat transfer correlations according to the vapor fraction, which improves accuracy across different operating conditions. Moreover, a comprehensive pressure balance model is established that spans the external piping, the reboiler, and the column sump liquid level to ensure the resulting natural circulation is stable. Geometric and operating variables are optimized simultaneously to deliver coordinated design choices under duty and layout constraints. The optimization is implemented in GAMS/48 and solved using SCIP solver. To demonstrate engineering applicability, the thermodynamic modelling results are compared with Aspen EDR simulations, revealing relative errors ranging from 3.8 % to 15.6 %. The optimized design increases the overall heat transfer coefficient by 16.60 % and reduces the required area by 13.86 %. Furthermore, stability analysis under varying heat duties reveals clear operational boundaries, highlighting the importance of coordinating liquid level and skirt height to maintain feasible natural circulation.

Open Access: Yes

DOI: 10.1016/j.applthermaleng.2025.129513

Evaluating the Effectiveness of Autorouting in PCB Design †

Peter Gulyas

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This research aims to determine an optimized set of parameters for Altium Designer’s built-in autorouting function when applied on two- or more-layer printed circuit board (PCB) designs. An experimental approach is employed, creating a specific PCB layout with pre-placed components. The autorouting function is utilized to generate trace connections between components, with different parameter settings being tested to assess their impact on routing quality, efficiency, and speed. Routing time will be a key metric measured during this evaluation. The resulting autorouted designs will then be compared to a manually routed PCB designed by an engineer, considering factors such as routing neatness and adherence to design rules. This research aims to determine the effectiveness of the autorouting tool in PCB designs while potentially reducing design time.

Open Access: Yes

DOI: 10.3390/engproc2024079060

Creating and using key network-performance indicators to support the design of change of enterprise infocommunication infrastructure

László Muka Gergely Muka

Publication Name: Proceedings of the 2012 International Symposium on Performance Evaluation of Computer and Telecommunication Systems Spects 12 Part of Summersim 2012 Multiconference

Publication Date: 2012-10-08

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Nowadays, an increasing number of organisations have to make decisions about the change and optimization of their enterprise infocommunication infrastructure. The usual approach of performance (using QoS, SLA) is not user (enterprise) centred and complex enough to help ICT (Information and Communication Technology) experts to support management decisions. © 2012 Society for Modeling & Sim.

Open Access: Yes

DOI: DOI not available

Flow Simulation in an Alga Photobioreactor Tested Under Laboratory Conditions

Roland Jančo Tibor Tolner Imre Neményi Miklos

Publication Name: Strojnicky Casopis Journal of Mechanical Engineering

Publication Date: 2024-05-01

Volume: 74

Issue: 1

Page Range: 35-44

Description:

For the purpose of efficient algae cultivation, the Photo Bio-Reactor (PBR) must be designed according to the needs of the algae to be cultivated. We performed our experiment with a loop reactor with a total volume of 14 liters. Among other things, the mixing of the gas and liquid phases, the value and change of the light intensity reaching the algae, and the degree of algae deposition on the walls of the equipment depend on the flow caused by the bubble column in the equipment. Using the ANSYS FLUENT simulation environment, we optimized the efficiency of the gas intake that determines the flow.

Open Access: Yes

DOI: 10.2478/scjme-2024-0004

Temporal dynamics of object location processing in allocentric reference frame

Péter Galambos György Persa Andrea Kóbor Ágoston Török Ferenc Honbolygó Valéria Csépe Péter Baranyi

Publication Name: Psychophysiology

Publication Date: 2017-09-01

Volume: 54

Issue: 9

Page Range: 1346-1358

Description:

The spatial location of objects is processed in egocentric and allocentric reference frames, the early temporal dynamics of which have remained relatively unexplored. Previous experiments focused on ERP components related only to egocentric navigation. Thus, we designed a virtual reality experiment to see whether allocentric reference frame-related ERP modulations can also be registered. Participants collected reward objects at the end of the west and east alleys of a cross maze, and their ERPs to the feedback objects were measured. Participants made turn choices from either the south or the north alley randomly in each trial. In this way, we were able to discern place and response coding of object location. Behavioral results indicated a strong preference for using the allocentric reference frame and a preference for choosing the rewarded place in the next trial, suggesting that participants developed probabilistic expectations between places and rewards. We also found that the amplitude of the P1 was sensitive to the allocentric place of the reward object, independent of its value. We did not find evidence for egocentric response learning. These results show that early ERPs are sensitive to the location of objects during navigation in an allocentric reference frame.

Open Access: Yes

DOI: 10.1111/psyp.12886

Short-period supply reliability evaluation of a gas pipeline network based on transient operation optimization and support vector regression

Lili Zuo Qian Chen Bohong Wang Kai Yang Jing Yan Petar Sabev Varbanov Ferenc Friedler Xiaokai Xing

Publication Name: Energy

Publication Date: 2025-09-15

Volume: 331

Issue: Unknown

Page Range: Unknown

Description:

The gas pipeline network is a critical infrastructure connecting downstream customers and upstream sources, and the gas supply condition of the gas network directly impacts people's lives. In this paper, a novel methodology is proposed to evaluate the short-period supply reliability of a gas pipeline system based on transient operation optimization and support vector regression. Firstly, supply and demand uncertainty characteristics are analyzed, and representative scenarios are selected through the improved Latin Hypercube Sampling method. Secondly, the transient peak-shaving characteristics are studied, and the physical transient peak-shaving operation optimization model is established to evaluate the satisfaction rate of gas customers and the system under representative scenarios. Then the Support Vector Regression model based on the improved Particle Swarm Optimization is established to predict the satisfaction rate of the customer or system under each random scenario, and the probabilities under different satisfaction degrees of the customer and system are given to reflect the supply reliability of a gas network. The proposed integrated methodology is verified by a specific gas pipeline system, and the results show that the maximum and the mean absolute error of the predicted satisfaction rate of the system's demand quantity can be reduced to 0.0070 and 0.0009, and the time consumed for the evaluation process can be reduced by 95 % compared to the traditional pure physical model. The proposed methodology can lay a solid foundation for the grasp of the short-period supply reliability of gas networks.

Open Access: Yes

DOI: 10.1016/j.energy.2025.136923

Wasserstein distance for OWA operators

Lucian Coroianu Istvan A. Harmati Robert Fuller

Publication Name: Fuzzy Sets and Systems

Publication Date: 2024-05-15

Volume: 484

Issue: Unknown

Page Range: Unknown

Description:

We suggest a distance measure for OWA operators. First we associate an OWA operator with a unique regular increasing monotone quantifier and then define the distance between two OWA operators as the Wasserstein-1 distance between their associated quantifiers.

Open Access: Yes

DOI: 10.1016/j.fss.2024.108931

Behavioral analysis of fuzzy cognitive map models by simulation

Miklós F. Hatwágner László T. Kóczy Vesa A. Niskanen

Publication Name: Ifsa Scis 2017 Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems

Publication Date: 2017-08-30

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Fuzzy Cognitive Maps (FCM) are widely applied to support decision making and for the prediction of the future behavior of systems. In this paper several real expert-defined models of an organization will be investigated. Simulations were performed in order to examine the asymptotic behavior of these models, especially to find (all) fixed point attractors, or to discover chaotic behavior. A sigmoid type of inference function was applied, and the effect of the steepness parameter on simulation results was investigated, too. It will be shown by several examples that the steepness parameter may even change the number and values of the final state vectors. In the end, the systematic study of the behavior of the models in terms of the changes of the (uncertain) relationship values among system components were studied.

Open Access: Yes

DOI: 10.1109/IFSA-SCIS.2017.8023345

New energy management and hybrid energy storage for metro railcar

Istvan Szenasy

Publication Name: 26th Electric Vehicle Symposium 2012 Evs 2012

Publication Date: 2012-12-01

Volume: 4

Issue: Unknown

Page Range: 2734-2742

Description:

This paper focuses on the use of model and simulation one of renewable energy. In this paper the results of simulation models by Matlab-Simulink for an urban-metro railcar and some newer methods for reducing the need value of capacitance for energy storage in cooperation by a Li-ion battery are presented. In this research was been investigated the Li-ion battery and the supercapacitor as hybrid energy storing device for the same task and its effectivness under operation of a suitable energy control system. The available decreasing ratio of the needed energy storage at case SCAP is 25 % to 40 % with this improved energy control method, which are significant values as decreasing in volume, mass and price. Mass reduction of our hybrid storage system is significant, about 60%.

Open Access: Yes

DOI: DOI not available