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Publications - 6374

Design and Implementation of a Modular Smart Home System Using ESP32 and Apple HomeKit Integration

Stefan Koprda Zoltan Balogh Gyorgy Molnar

Publication Name: Sisy 2025 IEEE 23rd International Symposium on Intelligent Systems and Informatics Proceedings

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: 125-130

Description:

This paper presents a modular smart home system integrating ESP32 microcontrollers with Apple HomeKit ecosystem to address scalability and data retention challenges in residential IoT deployments. The proposed solution employs the HomeSpan library for HomeKit-Compatible accessories, enabling secure local communication while maintaining compatibility with Apple's Home application. The key scientific contribution lies in the hybrid architecture combining real-time HomeKit control with a dedicated REST API server featuring SSL encryption and API-key authentication for historical data collection. The system addresses Apple Home app's limitation of lacking data retention capabilities through automated 5-minute data transmission intervals to a secure MariaDB database. Performance evaluation demonstrates stable operation across multiple sensor types (DHT22, PIR motion sensors) and actuators with modular deployment flexibility. Comparative analysis shows improved data persistence and analytics capabilities over standard HomeKit implementations while maintaining the security benefits of local communication protocols. The implementation achieves practical IoT deployment suitable for residential environments with enhanced comfort, safety, and energy efficiency monitoring capabilities.

Open Access: Yes

DOI: 10.1109/SISY67000.2025.11205419

Conceptual design of a negative emissions polygeneration plant for multiperiod operations using P-graph

Kathleen B. Aviso Ákos Orosz Raymond R. Tan Jean Pimentel Ferenc Friedler

Publication Name: Processes

Publication Date: 2021-02-01

Volume: 9

Issue: 2

Page Range: 1-19

Description:

Reduction of CO2 emissions from industrial facilities is of utmost importance for sustainable development. Novel process systems with the capability to remove CO2 will be useful for carbon management in the future. It is well-known that major determinants of performance in process systems are established during the design stage. Thus, it is important to employ a systematic tool for process synthesis. This work approaches the design of polygeneration plants with negative emission technologies (NETs) by means of the graph-theoretic approach known as the P-graph framework. As a case study, a polygeneration plant is synthesized for multiperiod operations. Optimal and alternative near-optimal designs in terms of profit are identified, and the influence of network structure on CO2 emissions is assessed for five scenarios. The integration of NETs is considered during synthesis to further reduce carbon footprint. For the scenario without constraint on CO2 emissions, 200 structures with profit differences up to 1.5% compared to the optimal design were generated. The best structures and some alternative designs are evaluated and compared for each case. Alternative solutions prove to have additional practical features that can make them more desirable than the nominal optimum, thus demonstrating the benefits of the analysis of near-optimal solutions in process design.

Open Access: Yes

DOI: 10.3390/pr9020233

Water-assisted production of polypropylene/boehmite composites

László Lendvai

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2020-01-01

Volume: 64

Issue: 2

Page Range: 128-135

Description:

In this study polypropylene (PP) matrix-based boehmite alumina (BA) reinforced composites were prepared batchwise in an internal mixer. BA particles up to 10 wt.% were incorporated by 1. traditional melt mixing and 2. in a novel, Water-Assisted (WA) way, called fast evaporation mixing, during which BA was dispersed in PP with the use of an aqueous carrier medium. The WA way with pure water as medium proved to be ineffective because of the presence of the Leidenfrost effect. Therefore, an additional agent, carboxymethyl cellulose (CMC) was used to increase the boiling temperature of the water. Mechanical, morphological and thermal properties of the composites were determined. Scanning electron microscopy images revealed a partially dispersed structure of BA within the PP matrix in all cases, where aggregates and dispersed particles were identified as well. The size of the agglomerates observed was the smallest when BA was incorporated by being dispersed in water/CMC firstly. The mechanical tests results indicated that the reinforcing effect of BA was also most prominent in this case. However, CMC had an opposite effect on PP, than BA thus reducing the overall enhancement in mechanical properties. Differential scanning calorimetry showed an increase in the crystallinity ratio of PP with increasing BA content, which indicates a nucleating effect of BA.

Open Access: Yes

DOI: 10.3311/PPME.13981

GEOMETRY VARIATION OF BALLASTED RAILWAY TRACKS DUE TO WEATHER CONDITIONS

Szabolcs Fischer Mykola Sysyn Jianxing Liu Vivien Jóvér

Publication Name: Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu

Publication Date: 2023-01-01

Volume: Unknown

Issue: 1

Page Range: 74-79

Description:

Purpose. Investigate and establish the relationship between track geometry measurements and weather conditions to determine the parameters that influence the lifetime of railway tracks' superstructure system. The study of ballasted beds of railway tracks is very important for operation and maintenance in case of main lines, industrial sidings and mine transport. Methodology. Determination of the annual load of the selected section based on the regulations. Compari of the track parameters measurements made by TrackScan 4.01 instrument in different seasons and temperatures. Among the parameters measured by the instrument, the track gauge, alignment, longitudinal level, and superelevation parameters are considered and analyzed in this article.Since the main lines' traffic are permanently loaded with passenger and freight transport and the industrial sidings and mine tracks are used in the production process, the examinations can only be done on tramway tracks during the standstills at night. The results of these measurement on tramway tracks can help to understand the identify of railway tracks' lifetime and can be used in mainlines, industrial and mining railway tracks. Findings. The change in the average values of selected track geometrical parameters is analyzed, considering the typical weather conditions. Based on the measurement and results, there is an evident connection between the evaluated results of track geometry measurements and the change in weather conditions. Originality. Finding the relationship between changes in track geometry values and weather conditions on the basis of an evaluation of track geometry measurements taken on average every third month. Practical value. The results can then be used as input data for determining the service life of the track superstructure in the case of tramways, mainlines, industrial and mining railway tracks.

Open Access: Yes

DOI: 10.33271/nvngu/2023-1/074

Do Eco-Emotions and Climate Change Perceptions Influence Environmentally Conscious Decisions? Implications for Business Strategies

Anushree Tandon Chuhong Wang Muhammad Danish Habib Attila Kurucz

Publication Name: Business Strategy and the Environment

Publication Date: 2026-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

Despite growing research on explicating travelers' decision-making processes regarding greener travel options, there remains potential for exploring nuances of different factors and mechanisms that may encourage higher green travel. Grounded in the propositions of the push–pull–mooring framework, our study attempts to explicate whether eco-emotions (anxiety and grief as push factors) and environmental cognitions (climate change perceptions and destination social responsibility as pull factors) influence travelers' green consumption values and green travel intentions. Data collected via Prolific from 291 green travelers was analyzed using covariance-based structural equation modeling to test the hypothesized associations. In general, the study results affirm the hypothesized push and pull effects for green consumption values, which in turn play a mediating role to amplify the effects of push and pull factors on green travel intentions, rather than substituting for them. The findings raise significant implications for theory and also provide actionable insights for developing operating and communication strategies for industry practitioners.

Open Access: Yes

DOI: 10.1002/bse.70548

Assessing the determinants of non-performing loans under financial crisis and health crisis: evidence from the MENA banks

Emira Kozarević Abdelaziz Hakimi Khalil Alnabulsi

Publication Name: Cogent Economics and Finance

Publication Date: 2022-01-01

Volume: 10

Issue: 1

Page Range: Unknown

Description:

The main objective of this paper is to investigate determinants of non-performing loans in the Middle East and North Africa region by exploring the role of bank-specific and macroeconomic factors, particularly in the period of the global financial crisis, as well as the COVID-19 pandemic, as a health crisis that translates to an economic crisis. This study includes 74 banks belonging to 11 MENA countries over the period 2005–2020 and uses the two-stage system generalized method of moment estimator. To conduct a comparative analysis, the whole sample is divided into two sub-samples. The first one is related to the Middle East countries and the second one covers North African countries. The empirical findings indicate that the level of non-performing loans is more sensitive to bank specifics than macroeconomic factors. When it comes to macroeconomic factors, macroeconomic environment and institutional quality significantly affect the level of NPLs. However, no significant effect has been detected regarding the impact of the COVID-19 pandemic.

Open Access: Yes

DOI: 10.1080/23322039.2022.2124665

Strain-specific biostimulant effects of chlorella and chlamydomonas green microalgae on medicago truncatula

Zoltán Futó Attila Farkas Gergely Maróti Margaret Mukami Gitau Benedikta Balla Vince Ördög

Publication Name: Plants

Publication Date: 2021-06-01

Volume: 10

Issue: 6

Page Range: Unknown

Description:

Microalgae have been identified to produce a plethora of bioactive compounds exerting growth stimulating effects on plants. The objective of this study was to investigate the plant-growth-promoting effects of three selected strains of eukaryotic green microalgae. The biostimulatory effects of two Chlorella species (MACC-360 and MACC-38) and a Chlamydomonas reinhardtii strain (cc124) were investigated in a Medicago truncatula model plant grown under controlled greenhouse conditions. The physiological responses of the M. truncatula A17 ecotype to algal biomass addition were characterized thoroughly. The plants were cultivated in pots containing a mixture of vermiculite and soil (1:3) layered with clay at the bottom. The application of live algae cells using the soil drench method significantly increased the plants’ shoot length, leaf size, fresh weight, number of flowers and pigment content. For most of the parameters analyzed, the effects of treatment proved to be specific for the applied algae strains. Overall, Chlorella application led to more robust plants with increased fresh biomass, bigger leaves and more flowers/pods compared to the control and Chlamydomonas-treated samples receiving identical total nutrients.

Open Access: Yes

DOI: 10.3390/plants10061060

Modelling of human color perception depending on quick color shifts on screen

Lorinc Garai András Horváth

Publication Name: 9th IEEE International Conference on Cognitive Infocommunications Coginfocom 2018 Proceedings

Publication Date: 2018-07-02

Volume: Unknown

Issue: Unknown

Page Range: 223-226

Description:

The eye is considered as the most important human sensory organ. Its important part is the retina, which converts light to neural impulses by several millions of sensor cells: rods and cones. To understand this process, modelling by computer simulation is required. The well-known phenomenon of afterimages is examined in this paper. When a fast color change on screen is performed, a color after image appears temporarily. This afterimage may result in a more intensive color perception. A model was established to characterize the color perception intensity and duration depending on color changes.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2018.8639909

Effect of Surface Modifications on Surface Roughness of Ti6Al4V Alloy Manufactured by 3D Printing, Casting, and Wrought

Péter Pinke Tünde Anna Kovács Hassanen Jaber J. Kónya Hajnalka Hargitai

Publication Name: Materials

Publication Date: 2023-06-01

Volume: 16

Issue: 11

Page Range: Unknown

Description:

This work aimed to comprehensively evaluate the influence of different surface modifications on the surface roughness of Ti6Al4V alloys produced by selective laser melting (SLM), casting and wrought. The Ti6Al4V surface was treated using blasting with Al2O3 (70–100 µm) and ZrO2 (50–130 µm) particles, acid etching with 0.017 mol/dm3 hydrofluoric acids (HF) for 120 s, and a combination of blasting and acid etching (SLA). It was found that the optimization of the surface roughness of Ti6Al4V parts produced by SLM differs significantly from those produced by casting or wrought processes. Experimental results showed that Ti6Al4V alloys produced by SLM and blasting with Al2O3 followed by HF etching had a higher surface roughness (Ra = 2.043 µm, Rz = 11.742 µm), whereas cast and wrought Ti6Al4V components had surface roughness values of (Ra = 1.466, Rz = 9.428 m) and (Ra = 0.940, Rz = 7.963 m), respectively. For Ti6Al4V parts blasted with ZrO2 and then etched by HF, the wrought Ti6Al4V parts exhibited higher surface roughness (Ra = 1.631 µm, Rz = 10.953 µm) than the SLM Ti6Al4V parts (Ra = 1.336 µm, Rz = 10.353 µm) and the cast Ti6Al4V parts (Ra = 1.075 µm, Rz = 8.904 µm).

Open Access: Yes

DOI: 10.3390/ma16113989