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Found 5164 publications

Shear buckling behaviour of beams with partial-depth stiffeners at the support

G. Hajdú Hartmut Pasternak

Publication Name: Thin Walled Structures

Publication Date: 2025-02-01

Volume: 207

Issue: Unknown

Page Range: Unknown

Description:

This paper presents the findings from experimental tests and numerical simulations on plate girders with various end post configurations. While EN 1993-1-5:2024 provides design rules for both rigid and non-rigid end posts, it does not address the shear resistance of partially stiffened webs. The use of partial-depth stiffeners faces risks due to the lack of thorough investigation into their mechanical behaviour. To explore this issue, small numbered experimental tests and large numbered parametric studies on beams with different web slenderness were conducted using advanced numerical simulations. The results indicated that the shear buckling capacity of girders is lower than the design recommendation when the web stiffener height is <50 % of the web height. For girders with full-height stiffeners, EN 1993-1-5:2024 yields safe results. The accuracy of the EN 1993-1-5:2024 design rule for partially stiffened beams was also evaluated and new and shear buckling design curves were proposed for girders with partial-depth stiffeners.

Open Access: Yes

DOI: 10.1016/j.tws.2024.112622

Normal wiggly probabilistic hesitant fuzzy-based TODIM approach for optimal solid waste disposal method selection

Dragan Pamucar Jawad Ali

Publication Name: Heliyon

Publication Date: 2025-01-30

Volume: 11

Issue: 2

Page Range: Unknown

Description:

The normal wiggly probabilistic hesitant fuzzy set (NWPHFS) enhances the conventional probabilistic hesitant fuzzy set (PHFS) by capturing not only explicit probabilistic information but also critical underlying details that may be hidden in the original inputs provided by decision-makers (DMs). This paper introduces a novel extension of the Tomada de Decisão Interativa Multicritério (TODIM) method, called the normal wiggly probabilistic hesitant fuzzy TODIM (NWPHFT) method based on the proposed distance measures of NWPHFSs. Initially, two novel basic operations over NWPHFSs—the subtraction and division operations—are defined. Additionally, several distance measures specific to normal wiggly probabilistic hesitant fuzzy sets are developed, and their properties are thoroughly examined. Furthermore, for scenarios where the weights of criteria are partially or completely unknown, two optimization models are established to determine these weights using the maximizing deviation approach and the Lagrange function technique, respectively. Next, the traditional TODIM approach is extended to develop the NWPHFT for addressing MCDM problems by utilizing the proposed distance measures and criteria weight determination models. The proposed method is then applied to a problem related to selecting solid waste disposal methods to demonstrate its practical applicability. Finally, comprehensive sensitivity analyses and comparisons are conducted to illustrate the stability and effectiveness of the proposed approach.

Open Access: Yes

DOI: 10.1016/j.heliyon.2025.e41908

Multi-Solution Heat Exchanger Network Synthesis for Turbo-Expander-Based Cryogenic CO2 Capture Technology

Ákos Orosz Jaka Sunarso Dhanaraj Turunawarasu Viknesh Andiappan Bing Shen How Yat Choy Wong Ferenc Friedler

Publication Name: Industrial and Engineering Chemistry Research

Publication Date: 2025-01-22

Volume: 64

Issue: 3

Page Range: 1664-1679

Description:

Cryogenic separation of CO2 is a potential technology that can benefit from energy efficiency improvements. However, the current conventional and emerging cryogenic technologies face challenges in terms of high utility consumption. The high utility requirement leads to increasing operational costs and emissions due to the production of required utilities from external energy sources. This issue can be solved if the heat recovery potential of the technology can be realized. Heat recovery enables further improvement in energy efficiency that is required to elevate the feasibility of cryogenic separation. This paper explores heat recovery opportunities between hot and cold streams in a novel cryogenic CO2 capture technology known as Turbo-Expander-based Cryogenic Distillation (CryoDT). This is achieved using P-HENS, a P-graph-based heat exchanger network synthesis tool where multiple feasible heat exchanger network configurations are generated to determine the options that effectively recover process heat to reduce utility consumption. Moreover, the solutions generated by P-HENS are benchmarked with other tools like Aspen Energy Analyzer, by comparing the number of required heat exchangers, along with the associated capital and operating costs. For the predefined hot and cold process streams of the novel technology, the total number of heat exchangers present in the network was lower in the recommended design using P-HENS (i.e., 9 heat exchangers) as opposed to Aspen Energy Analyzer (16 heat exchangers) while maintaining similar energy consumption levels. This indicates that there is a further opportunity to reduce capital costs as a result of less heat exchangers. The CryoDT configuration that is integrated with a heat exchanger network offers significant economic advantages as opposed to other existing cryogenic processes in the market such as the Ryan Holmes and Controlled Freeze Zone (CFZ) processes. Despite its high capital cost, the CryoDT process demonstrates significantly lower operating cost relative to the other two processes. Hence, while the initial investment is substantial, the CryoDT process is much more cost efficient to operate. The low operating cost is attributed to its higher energy efficiency and minimal energy penalties, with only 0.26 GJ/tonne of CO2 compared with 0.82 GJ/tonne of CO2 for the CFZ process and 2.33 GJ/tonne of CO2 for Ryan Holmes. In contrast, the Ryan Holmes process, despite its low capital cost, incurs extremely high annual operational costs, rendering it less economic in the long term. The CFZ process, with its moderate operating cost, presents a balance between capital cost and operational efficiency.

Open Access: Yes

DOI: 10.1021/acs.iecr.4c03469

Determinants of ChatGPT adoption among students in higher education: the moderating effect of trust

Morteza Ghobakhloo Mohammad Iranmanesh Behzad Foroughi Nagaletchimee Annamalai Abderahman Rejeb Bita Naghmeh-Abbaspour Madugoda Gunaratnege Senali

Publication Name: Electronic Library

Publication Date: 2025-01-22

Volume: 43

Issue: 1

Page Range: 1-21

Description:

Purpose: ChatGPT is a cutting-edge chatbot powered by artificial intelligence that could revolutionise and advance the teaching and learning process. Drawing on the technology acceptance model (TAM) and information system (IS) success model, this study aims to investigate determinants of students’ intention to use ChatGPT for education purposes. Design/methodology/approach: The partial least squares technique was used to analyse 406 usable data collected from university students in Malaysia. Findings: The results confirmed the relationships between perceived usefulness (PU), perceived ease of use (PEU), attitude and intention to use proposed by TAM. PU and PEU are influenced by system quality. Surprisingly, trust in information moderates negatively the influences of PEU and PU on attitude. Practical implications: The findings provide insight for higher education institutions, unit instructors and ChatGPT developers on what may promote the use of ChatGPT in higher education. Originality/value: The study contributes to the literature by exploring the determinants of ChatGPT adoption, extending the TAM model by incorporating IS success factors and assessing the moderating effect of trust in information.

Open Access: Yes

DOI: 10.1108/EL-12-2023-0293

Contribution to the taxonomy of the Rotundabaloghia (Circobaloghia) mites (Acari: Uropodina: Rotundabaloghiidae)

Jenő Kontschán

Publication Name: Acta Phytopathologica Et Entomologica Hungarica

Publication Date: 2025-01-21

Volume: 59

Issue: 2

Page Range: 176-186

Description:

Four new Rotundabaloghia (Circobaloghia) species are described from South America and South-East Asia based on the collection of the Natural History Museum, London, UK. Rotundabaloghia (Circobaloghia) salebrosa sp. nov. was collected in Malaysia, Rotundabaloghia (Circobaloghia) bakerae sp. nov. was found in Sarawak (Malaysia), Rotundabaloghia (Circobaloghia) microseta sp. nov. is described from Guyana and Rotundabaloghia (Circobaloghia) peritremata sp. nov. was reported from Borneo (Indonesia).

Open Access: Yes

DOI: 10.1556/038.2024.00228

Tracing knowledge diffusion trajectories in the research field of cyberbullying

E. Süle Imen Zrelli Abderahman Rejeb Karim Rejeb

Publication Name: Heliyon

Publication Date: 2025-01-15

Volume: 11

Issue: 1

Page Range: Unknown

Description:

In today's digital age, cyberbullying has emerged as a pervasive issue that affects individuals across various social media platforms and digital communication channels. This review explores the developmental trajectory of cyberbullying as an interdisciplinary academic field, employing a unique combination of co-word analysis and main path analysis (MPA) across a substantial body of 5183 documents. This integrated methodological approach allows for a nuanced examination of the evolution of themes and influential works within the realm of cyberbullying research. The findings highlight a complex landscape where initial focus areas, such as the behavioral and psychological triggers of cyberbullying, progressively expand towards exploring effective preventive measures and intervention strategies. Key themes identified include the impact of digital literacy, the dual role of social media as both a vector and a tool against cyberbullying, and the potential of technological advancements in detecting and mitigating cyberbullying. This comprehensive mapping and analysis deepens our understanding of cyberbullying and highlights the dynamic nature of this field, suggesting new directions for future research and practical applications to effectively address cyberbullying across various social and technological contexts. This study represents a pioneering effort in synthesizing a broad spectrum of research to offer detailed insights into the changing dynamics of cyberbullying, marking a significant contribution to both academic knowledge and practical approaches to handling cyberbullying.

Open Access: Yes

DOI: 10.1016/j.heliyon.2024.e41141

A novel Complex q-rung orthopair fuzzy Yager aggregation operators and their applications in environmental engineering

Dragan Pamucar Tahir Mahmood Jabbar Ahmmad Hafiz Muhammad Waqas

Publication Name: Heliyon

Publication Date: 2025-01-15

Volume: 11

Issue: 1

Page Range: Unknown

Description:

Improving human health and comfort in buildings requires efficient temperature regulation. Temperature control system has a significant contribution in minimizing the impact of climate change. Temperature control system is used in industry to control temperature. The polar form of complex Pythagorean fuzzy set is a limited notion because when decision makers take the value for membership degree as 0.71+ι0.81 then we can observe that the basic condition for complex Pythagorean fuzzy set fails to hold that is r=0.712+0.812=1.3661∉[0,1]. Moreover, we can observe that the Cartesian form of a complex Pythagorean fuzzy set is also a limited notion because it can never discus advance data. Hence keeping in mind these limitations of the existing notions, in this article, we have explored the Cartesian form of a complex q-rung orthopair fuzzy set. Moreover, we have developed the Yager operational laws based on a Cartesian form of complex q-rung orthopair fuzzy set. We have introduced aggregation theory named complex q-rung orthopair fuzzy Yager weighted average and complex q-rung orthopair fuzzy Yager weighted geometric aggregation operators in Cartesian form. Based on these aggregation operators, we have initiated a multi-attribute group decision-making (MAGDM) approach to define the reliability and authenticity of the developed theory. Furthermore, we have utilized this device algorithm in the selection of a temperature control system. The comparative study of the delivered approach shows the advancement and superiority of the delivered approach.

Open Access: Yes

DOI: 10.1016/j.heliyon.2025.e41668

Dr. Steinberger Sarolta (1875–1966) és az ártatlanság vélelme

Bóka Dalma Göndör Éva Zsák Brúnó

Publication Name: Orvosi Hetilap

Publication Date: 2025-01-12

Volume: 166

Issue: 2

Page Range: 77-80

Description:

No description provided

Open Access: Yes

DOI: 10.1556/650.2025.HO2817

Rolling Contact fatigue Defects and a New Approach to Rail Material Management

Éva Lublóy Zoltán Major Szigeti Cecília Róbert Horváth

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2025-01-01

Volume: 22

Issue: 4

Page Range: 227-246

Description:

This article describes the current method of calculating the Hertzian contact stress and the corresponding shear stress occurring in the rail head at the rail-wheel contact and highlights the false sense of security that this approach creates among experts. The authors then present a method that is easy to implement in spreadsheet software and provides realistic results. In light of the results obtained, it is shown that it is not possible to prevent defects induced by the occurring stresses but only to keep them within limits by means of rail machining, which is a realistic objective, without significantly limiting the throughput capacity of the railway track. The combined effects of rail machining and natural wear cause the cross-sectional area and inertia and thus, the load-bearing capacity of the rails to decrease continuously. If the limit is exceeded, the rails may be installed again in less heavily used track sections and continue functioning. At the end of their service life, the track owner sells them as used rail scrap. If possible, recasting them as electro-steels, can significantly reduce the production costs and the amount of CO2 emitted during production.

Open Access: Yes

DOI: DOI not available