MDPI - Publisher of Open Access Journals

21 pages, 8725 KiB

Open AccessArticle

Formal Analysis of Rational Exchange Protocols Based on the Improved Buttyan Model

by Meihua Xiao, Lina Chen, Ke Yang and Zehuan Li

Symmetry 2025, 17(7), 1033; https://doi.org/10.3390/sym17071033 - 1 Jul 2025

A rational exchange protocol is a type of e-commerce protocol that aims to maximize the participants’ own interests. The Buttyan model is commonly used to analyze the security of such protocols. However, this model has limitations in dealing with uncertainties and false messages [...] Read more.

A rational exchange protocol is a type of e-commerce protocol that aims to maximize the participants’ own interests. The Buttyan model is commonly used to analyze the security of such protocols. However, this model has limitations in dealing with uncertainties and false messages in rational exchanges. To address these shortcomings, this paper proposes a formal analysis method based on Bayesian games. By incorporating participants’ types and beliefs, the Buttyan model is extended to enhance its ability to express uncertainties. Additionally, attack messages are introduced to simulate the potential fraudulent behaviors that participants may exploit through the security vulnerabilities in the protocol. Finally, the improved model is applied to conduct a formal analysis of a rational electronic contract signing protocol, and it is found that the protocol meets the usability requirements. The results show that this method can be effectively applied to the security analysis of rational exchange protocols, thereby enhancing the security of the e-commerce transaction process. Full article

(This article belongs to the Section Computer)

► Show Figures

Figure 1

15 pages, 14259 KiB

Open AccessArticle

Repetition Frequency-Dependent Formation of Oxidized LIPSSs on Amorphous Silicon Films

by Liye Xu, Wei Yan, Weicheng Cui and Min Qiu

Photonics 2025, 12(7), 667; https://doi.org/10.3390/photonics12070667 (registering DOI) - 1 Jul 2025

Abstract

Laser-induced periodic surface structures (LIPSSs) produced via ultrafast laser-induced oxidation offer a promising route for high-quality nanostructuring, with reduced thermal damage compared to conventional ablation-based methods. However, the influence of laser repetition frequency on the formation and morphology of oxidized LIPSSs remains insufficiently [...] Read more.

Laser-induced periodic surface structures (LIPSSs) produced via ultrafast laser-induced oxidation offer a promising route for high-quality nanostructuring, with reduced thermal damage compared to conventional ablation-based methods. However, the influence of laser repetition frequency on the formation and morphology of oxidized LIPSSs remains insufficiently explored. In this study, we systematically investigate the effects of varying the femtosecond laser repetition frequency from 1 kHz to 100 kHz while keeping the total pulse number constant on the oxidation-induced LIPSSs formed on amorphous silicon films. Scanning electron microscopy and Fourier analysis reveal a transition between two morphological regimes with increasing repetition frequency: at low frequencies, the long inter-pulse intervals result in irregular, disordered oxidation patterns; at high frequencies, closely spaced pulses promote the formation of highly ordered, periodic surface structures. Statistical measurements show that the laser-modified area decreases with frequency, while the LIPSS period remains relatively stable and the ridge width exhibits a peak at 10 kHz. Finite-difference time-domain (FDTD) and finite-element simulations suggest that the observed patterns result from a dynamic balance between light-field modulation and oxidation kinetics, rather than thermal accumulation. These findings advance the understanding of oxidation-driven LIPSS formation dynamics and provide guidance for optimizing femtosecond laser parameters for precise surface nanopatterning. Full article

1210 KiB

Open AccessArticle

Erythrocyte Load in Cerebrospinal Fluid Linked with Hippocampal Atrophy in Alzheimer’s Disease

by Rafail Christodoulou, Georgios Vamvouras, Laura Lorentzen and Evros Vassiliou

J. Clin. Med. 2025, 14(13), 4670; https://doi.org/10.3390/jcm14134670 (registering DOI) - 1 Jul 2025

Abstract

Background: Alzheimer’s disease is a neurodegenerative disease of unknown etiology. Employing a combination of techniques such as imaging modalities, cognitive tests and medical history evaluations is considered to be a reliable approach in diagnosing the disease. A characteristic feature of Alzheimer’s disease is [...] Read more.

Background: Alzheimer’s disease is a neurodegenerative disease of unknown etiology. Employing a combination of techniques such as imaging modalities, cognitive tests and medical history evaluations is considered to be a reliable approach in diagnosing the disease. A characteristic feature of Alzheimer’s disease is the gradual atrophy of the hippocampus, which is also seen with aging but at a faster rate in individuals suffering from the disease. The trigger responsible for the atrophy remains unknown. Methods: In this study, patients were assessed using MRI brain imaging, blood and cerebrospinal fluid analysis. Results: The findings indicate that the levels of erythrocytes in the cerebrospinal fluid have a statistically significant longitudinal predictive marker effect on hippocampal atrophy. Mean arterial pressure showed modest statistical significance in hippocampal volume only in the Alzheimer’s disease group. Conclusions: The results of the study point to the significance of cerebrospinal fluid homeostasis in terms of elements capable of causing hippocampal atrophy under chronic conditions. Monitoring of the presence of erythrocytes in cerebrospinal fluid and their related metabolites may be of clinical significance in the long-term management of Alzheimer’s disease. Full article

(This article belongs to the Section Clinical Neurology)

► Show Figures

Figure 1

766 KiB

Open AccessArticle

Independence Requirement Analysis for Common-Mode Analysis of Aircraft System Safety Based on AADL

by Hongze Ruan, Fan Qi, Xiaohui Wei, Yadong Zhou and Zhong Lu

Aerospace 2025, 12(7), 603; https://doi.org/10.3390/aerospace12070603 (registering DOI) - 1 Jul 2025

Abstract

Common-mode analysis (CMA) is a qualitative analytical method used to support the evaluation of independence in the system safety assessment of civil aircraft. In traditional CMA, independence requirements are usually identified by evaluating the combination of events using the fault tree AND-gates. This [...] Read more.

Common-mode analysis (CMA) is a qualitative analytical method used to support the evaluation of independence in the system safety assessment of civil aircraft. In traditional CMA, independence requirements are usually identified by evaluating the combination of events using the fault tree AND-gates. This approach is cumbersome and highly dependent on the skills and experiences of system safety engineers. An Architecture Analysis and Design Language (AADL)-based methodology is proposed to derive independence requirements for CMA. Error propagation data in AADL is extracted to develop a fault propagation model. Subsequently, potential factors contributing to common-mode failures (CMFs) are identified using the fault propagation model. A Primary Flight Computer (PFC) of an aircraft is used as a case study to illustrate the effectiveness of our proposed method. Full article

(This article belongs to the Section Aeronautics)

2331 KiB

Open AccessArticle

Unveiling the Biotoxicity Mechanisms of Cancer-Selective Thulium Oxide Nanoparticles

by Michael Valceski, Anson Tsan Yin O, Alice O’Keefe, Sarah Vogel, Elette Engels, Kiarn Roughley, Abass Khochaiche, Dylan Potter, Carolyn Hollis, Anatoly Rosenfeld, Michael Lerch, Stéphanie Corde and Moeava Tehei

J. Nanotheranostics 2025, 6(3), 17; https://doi.org/10.3390/jnt6030017 (registering DOI) - 1 Jul 2025

Abstract

High-Z nanoparticles (NPs) have the potential to revolutionize cancer radiotherapy by radiosensitising tumours. This is particularly important for radioresistant cancers such as glioblastoma. A newer NP candidate in this area is thulium oxide nanoparticles (TmNPs). However, prior to clinical assessment, ideal NP characteristics, [...] Read more.

High-Z nanoparticles (NPs) have the potential to revolutionize cancer radiotherapy by radiosensitising tumours. This is particularly important for radioresistant cancers such as glioblastoma. A newer NP candidate in this area is thulium oxide nanoparticles (TmNPs). However, prior to clinical assessment, ideal NP characteristics, including biocompatibility, biosafety, and preferential uptake in cancer, should be assessed. This in vitro study compares the effects of TmNP treatment, without radiation, on 9L gliosarcoma (9LGS), a well-established glioblastoma cell model, with exposure to Madin Darby Canine Kidney (MDCK) cells, a widely used non-cancerous cell model. The findings demonstrated selective uptake of TmNPs in 9LGS over MDCK following treatment. A biological assessment of toxicity confirmed minimal long-term effects on MDCK, whilst TmNPs were observed to induce some notable cell death in 9LGS. Excessive TmNP uptake in 9LGS over time was observed to induce cell vacuolisation, which resulted in cell death via necrosis. It was concluded that this was the explanation for the underlying mechanisms of TmNP toxicity in cancer cells. This study was therefore able to demonstrate not only that TmNPs are a biocompatible, cancer-selective candidate for radiosensitiser usage, but further provided a theory to explain its mechanisms of cancer cell toxicity. Full article

► Show Figures

Graphical abstract

41 pages, 1052 KiB

Open AccessArticle

The Tropical Peatlands in Indonesia and Global Environmental Change: A Multi-Dimensional System-Based Analysis and Policy Implications

by Yee Keong Choy and Ayumi Onuma

Reg. Sci. Environ. Econ. 2025, 2(3), 17; https://doi.org/10.3390/rsee2030017 - 1 Jul 2025

Abstract

Tropical peatlands store approximately 105 gigatons of carbon (GtC), serving as vital long-term carbon sinks, yet remain critically underrepresented in climate policy. Indonesia peatlands contain 57GtC—the largest tropical peatland carbon stock in the Asia–Pacific. However, decades of drainage, fires, and lax enforcement practices [...] Read more.

Tropical peatlands store approximately 105 gigatons of carbon (GtC), serving as vital long-term carbon sinks, yet remain critically underrepresented in climate policy. Indonesia peatlands contain 57GtC—the largest tropical peatland carbon stock in the Asia–Pacific. However, decades of drainage, fires, and lax enforcement practices have degraded vast peatland areas, turning them from carbon sinks into emission sources—as evidenced by the 1997 and 2015 peatland fires which emitted 2.57 Gt CO₂eq and 1.75 Gt CO₂eq, respectively. Using system theory validated against historical data (1997–2023), we develop a causal loop model revealing three interconnected feedback loops driving irreversible collapse: (1) drainage–desiccation–oxidation, where water table below −40 cm triggers peat oxidation (2–5 cm subsistence) and fires; (2) fire–climate–permafrost, wherein emissions intensify radiative forcing, destabilizing monsoons and accelerating Arctic permafrost thaw (+15% since 2000); and (2) economy–governance failure, perpetuated by palm oil’s economic dominance and slack regulatory oversight. To break these vicious cycles, we propose a precautionary framework featuring IoT-enforced water table (≤40 cm), reducing emissions by 34%, legally protected “Global Climate Stabilization Zones” for peat domes (>3 m depth), safeguarding 57 GtC, and ASEAN transboundary enforcement funded by a 1–3% palm oil levy. Without intervention, annual emissions may reach 2.869 GtCO₂e by 2030 (Nationally Determined Contribution’s business-as-usual scenario). Conversely, rewetting 590 km²/year aligns with Indonesia’s FOLU Net Sink 2030 target (−140 Mt CO₂e) and mitigates 1.4–1.6 MtCO₂ annually. We conclude that integrating peatlands as irreplaceable climate infrastructure into global policy is essential for achieving Paris Agreement goals and SDGs 13–15. Full article

13 pages, 1606 KiB

Open AccessReview

Advances in 3D-Printed Implants for Facial Plastic Surgery

by Joan Birbe Foraster

Surg. Tech. Dev. 2025, 14(3), 22; https://doi.org/10.3390/std14030022 - 1 Jul 2025

Abstract

Facial reconstruction presents complex challenges due to the intricate nature of craniofacial anatomy and the necessity for individualized treatment. Conventional reconstructive methods—such as autologous bone grafts and prefabricated alloplastic implants—pose limitations, including donor site morbidity, implant rejection, and suboptimal aesthetic results. The emergence [...] Read more.

Facial reconstruction presents complex challenges due to the intricate nature of craniofacial anatomy and the necessity for individualized treatment. Conventional reconstructive methods—such as autologous bone grafts and prefabricated alloplastic implants—pose limitations, including donor site morbidity, implant rejection, and suboptimal aesthetic results. The emergence of 3D printing technology has introduced patient-specific implants (PSIs) that enhance anatomical fit, functional restoration, and biocompatibility. This review outlines the evolution of 3D-printed implants, key materials, computer-assisted design (CAD), and their applications across trauma, oncology, congenital conditions, and aesthetics. It also addresses current challenges and explores future directions, such as bioprinting, smart implants, and drug-eluting coatings. Full article

(This article belongs to the Special Issue New Insights into Plastic Aesthetic and Regenerative Surgery)

16 pages, 1441 KiB

Open AccessReview

Focal and Segmental Glomerulosclerosis: A Comprehensive State-of-the-Art Review

by Dearbhail Ni Cathain, Donnchadh Reidy, Serena Bagnasco and Sam Kant

Sclerosis 2025, 3(3), 24; https://doi.org/10.3390/sclerosis3030024 - 1 Jul 2025

Abstract

Focal and segmental glomerulosclerosis (FSGS) describes a histological pattern of injury seen by light microscopy in kidney biopsy specimens and is the end result of various injuries to the podocyte. Our understanding of this disease entity has evolved greatly since it was first [...] Read more.

Focal and segmental glomerulosclerosis (FSGS) describes a histological pattern of injury seen by light microscopy in kidney biopsy specimens and is the end result of various injuries to the podocyte. Our understanding of this disease entity has evolved greatly since it was first described, with particular focus on changes in the classification of FSGS as a disease entity and expansion in our understanding of the underlying pathophysiology. The incidence and prevalence of FSGS and FSGS-associated end-stage kidney disease (ESKD) have increased globally, particularly in the United States; it is now the most common primary glomerular disorder in those with ESKD. APOL-1 is likely responsible for this epidemiological trend in kidney disease in the US and is an important focus of clinical trials and potential targeted therapies. Currently, the goal of treatment in FSGS is to achieve remission of proteinuria and to prevent progression to ESKD. Remission is achieved by using immunosuppressive therapies in primary FSGS, but treatment in secondary and genetic FSGS is largely supportive. Recurrent FSGS (rFSGS) post-transplantation remains a significant clinical challenge to nephrologists; current monitoring and treatment strategies are based on retrospective meta-analysis and observational studies with no clear consensus as to the optimum approach. Emerging therapies are focused on developing more targeted interventions in genetic and secondary FSGS. This review article aims to comprehensively explore this multifaceted disease entity. Full article

51 pages, 5106 KiB

Open AccessArticle

Evaluating Solar Energy Potential Through Clear Sky Index Characterization Across Elevation Profiles in Mozambique

by Fernando Venâncio Mucomole, Carlos Augusto Santos Silva and Lourenço Lázaro Magaia

Solar 2025, 5(3), 30; https://doi.org/10.3390/solar5030030 - 1 Jul 2025

Abstract

The characteristics and types of the sky can greatly influence photovoltaic (PV) power generation, potentially leading to a reduction in both the lifespan and efficiency of the entire system. Driven by the challenge of addressing fluctuations in solar PV energy utilization, the aim [...] Read more.

The characteristics and types of the sky can greatly influence photovoltaic (PV) power generation, potentially leading to a reduction in both the lifespan and efficiency of the entire system. Driven by the challenge of addressing fluctuations in solar PV energy utilization, the aim was to assess the solar energy potential by analyzing the clear sky index

(K_{t}^{*})

across elevation profiles. To achieve this, a theoretical model for determining

K_{t}^{*}

was employed, which encapsulated the solar energy analysis. Initially, solar energy data collected from approximately 16 stations in various provinces of Mozambique, as part of the solar energy measurement initiatives by INAM, FUNAE, AERONET, and Meteonorm, was processed. Subsequently, the clear sky radiation was calculated, and

K_{t}^{*}

was established. The statistical findings indicate a reduction in energy contribution from the predictors, accounting for 28% of the total incident energy; however, there are progressive increases averaging around ~0.02, with

K_{t}^{*}

values ranging from 0.4 to 0.9, demonstrating a strong correlation between 0.7 and 0.9 across several stations and predictor parameters. No significant climate change effects were noted. The radiation flux is directed from areas with higher

K_{t}^{*}

to those with lower values, as illustrated in the heat map. The region experiences an increase in atmospheric parameter deposition, with concentrations around ~0.20, yet there remains a substantial energy flow potential of 92% for PV applications. This interaction can also be applied in other locations to assess the potential for available solar energy, as the analyzed solar energy spectrum aligns closely with the theoretical statistical calibration of energy distribution relevant to the global solar energy population process. Full article

(This article belongs to the Topic Solar Forecasting and Smart Photovoltaic Systems)

► Show Figures

Figure 1

28 pages, 2052 KiB

Open AccessReview

Cell-Free Protein Synthesis Reactor Formats: A Brief History and Analysis

by Dallin M. Chipman, Anna C. Woolley, Davu N. Chau, William A. Lance, Joseph P. Talley, Tyler P. Green, Benjamin C. Robbins and Bradley C. Bundy

SynBio 2025, 3(3), 10; https://doi.org/10.3390/synbio3030010 - 1 Jul 2025

Abstract

Cell-free protein synthesis (CFPS) has transformed protein production capabilities by eliminating cellular constraints, enabling the rapid expression of difficult-to-produce proteins in an open, customizable environment. As CFPS applications expand from fundamental research to industrial production, therapeutic manufacturing, and point-of-care diagnostics, the diverse array [...] Read more.

Cell-free protein synthesis (CFPS) has transformed protein production capabilities by eliminating cellular constraints, enabling the rapid expression of difficult-to-produce proteins in an open, customizable environment. As CFPS applications expand from fundamental research to industrial production, therapeutic manufacturing, and point-of-care diagnostics, the diverse array of reactor formats has become increasingly important yet challenging to navigate. This review examines the evolution and characteristics of thirteen major CFPS reactor formats, from traditional batch systems to advanced platforms. The historical development of CFPS reactors from the 1960s to present day is presented. Additionally, for each format, operational principles, advantages, limitations, and notable applications are evaluated. The review concludes with a comparative assessment of reactor performance across critical parameters, including productivity, scalability, technical complexity, environmental stability, and application suitability. To our knowledge this structured analysis is the first to focus predominantly on the various reactor formats of cell-free systems and to provide a guide to assist researchers in choosing the reactor type that best fits their specific applications. Full article

19 pages, 567 KiB

Open AccessReview

International Patterns in Public Perceptions and Hesitancy Towards a Combined COVID-19 and Influenza Vaccination: A Scoping Review of Five Studies

by Karan Varshney, Ivana Skakic, Prerana Ghosh, Maya V. Raj and Darshan Shet

COVID 2025, 5(7), 103; https://doi.org/10.3390/covid5070103 - 1 Jul 2025

Abstract

Introduction: COVID-19 and influenza are viruses that have been major causes of morbidity and mortality worldwide. While a combination vaccine for these two viruses is currently in development, little is known about public perceptions and attitudes towards such a vaccine. Therefore, we have [...] Read more.

Introduction: COVID-19 and influenza are viruses that have been major causes of morbidity and mortality worldwide. While a combination vaccine for these two viruses is currently in development, little is known about public perceptions and attitudes towards such a vaccine. Therefore, we have aimed to conduct a scoping review to evaluate the attitudes and reasons for the acceptance/rejection of a combination COVID-19 and influenza vaccination. Material and Methods: Our review has followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines. Search terms included those on COVID-19, influenza, and combination vaccines. Searches were conducted in a total of 10 different databases, as follows: Embase, Global Health, Google Scholar, CINAHL, Medline, Scopus, ScienceDirect, PubMed, PsycINFO, and Web of Science. Results: Searches across all databases produced a total of 1763 results, of which five studies were deemed to be eligible for this review. Data from included studies encompassed a total of 20,581 participants across 14 countries. Generally, participants had favorable views towards a combination vaccine. However, attitudes varied by region, demographics, and prior vaccine exposure. Reasons provided for accepting a combination vaccine include low cost, reasonable effectiveness, fewer injections, and higher safety. However, reasons for rejection of a potential combination vaccine include a potential lack of evidence and studies regarding its effectiveness and a fear of possible side effects. Conclusions: There are generally positive attitudes and perceptions towards a combination vaccination for COVID-19 and influenza, and there are also specific segments of populations that may show hesitancy towards such a vaccine. Vaccination delivery programs should clearly demonstrate that these vaccines are safe and must concurrently address false rumors and misinformation. Ensuring that as many people as possible can receive the vaccination without barriers via equity in access should be a public health priority. It is also important to recognize the limitations of this work, especially that the review was limited to five studies, the majority of which were cross-sectional and relied on self-reporting. Full article

(This article belongs to the Section COVID Public Health and Epidemiology)

► Show Figures

Figure 1

25 pages, 1282 KiB

Open AccessReview

A Scoping Review of How High-Income Country HIV Guidelines Define, Assess, and Address Oral ART Adherence

by Dominic Chu, Kim Engler, Tibor Schuster, Romain Palich, Joel Ishak and Bertrand Lebouché

Venereology 2025, 4(3), 11; https://doi.org/10.3390/venereology4030011 - 1 Jul 2025

Abstract

Background/Objectives: An optimal approach to addressing oral antiretroviral therapy (ART) adherence remains unclear in the research literature. This review aimed to identify definitions and thresholds of adherence, proposed methods and frequencies of evaluating adherence levels, barriers to adherence, and interventions to address adherence [...] Read more.

Background/Objectives: An optimal approach to addressing oral antiretroviral therapy (ART) adherence remains unclear in the research literature. This review aimed to identify definitions and thresholds of adherence, proposed methods and frequencies of evaluating adherence levels, barriers to adherence, and interventions to address adherence problems. Methods: A scoping review of HIV guidelines drew on guidance from the Joanna Briggs Institute. Eligible English and French guidelines and their updates concerned adults with HIV and oral ART from developed countries and international health organizations from 2017 to May 2023. Three databases were systematically searched, along with the gray literature. Then, a targeted search for omitted developed countries was conducted. Document selection and data charting were performed with two reviewers for 20% of records and full texts, followed by an independent review. Inductive–deductive content analysis of extracted data was performed using NVivo 14 software. Results: Twenty-four guidelines were identified from seven countries and two international health organizations. Only two defined ART adherence, and none offered a threshold for adequate adherence. Most guidelines (n = 22/24) reported adherence interventions, 20 guidelines (83%) identified adherence barriers, 20 guidelines (83%) noted variable methods to evaluate adherence, and 17 guidelines (71%) proposed a range of frequencies for assessing adherence. Conclusions: This review underscored a lack of consensus around adherence and its management. Very few guidelines defined adherence, none proposed an optimal threshold, and there was no agreement on how to gauge adherence. These gaps and variability raise questions about how clinicians manage adherence in practice. More systematic and preventative approaches to monitoring adherence may be needed. Full article

18 pages, 2156 KiB

Open AccessArticle

The TOR Regulatory Mechanism Controls the Metabolism of Nitrate and the Fermentation Activity in the Yeast Dekkera bruxellensis GDB 248

by Karolini Miranda, Beatriz Câmara de Melo, Gilberto Henriques Teles, Irina Charlot Peña-Moreno, Rafael Barros de Souza and Marcos Antonio de Morais, Jr.

Microbiol. Res. 2025, 16(7), 143; https://doi.org/10.3390/microbiolres16070143 - 1 Jul 2025

Abstract

Dekkera bruxellensis is already known for its great biotechnological potential, part of this due to the ability to assimilate nitrate during fermentation. Despite the previous works on nitrogen metabolism in this yeast, especially regarding nitrate assimilation, the relation between this metabolism and the [...] Read more.

Dekkera bruxellensis is already known for its great biotechnological potential, part of this due to the ability to assimilate nitrate during fermentation. Despite the previous works on nitrogen metabolism in this yeast, especially regarding nitrate assimilation, the relation between this metabolism and the TOR (Target of Rapamycin) regulatory mechanism remains unexplored. This connection may reveal key regulatory mechanisms to maximize its fermentative performance and biotechnological use. Herein, we evaluated the physiological, metabolic, and gene expression profile of D. bruxellensis GDB 248 cultivated in ammonium and nitrate as nitrogen sources in the presence of TOR complex 1 (TORC1) inhibitor rapamycin. Our results showed that inhibition of the TORC1 significantly reduces cell growth and fermentative capacity, especially in nitrate media. Gene expression analysis revealed that TORC1 plays a central role in regulating genes involved in nitrate assimilation and the adaptive performance of D. bruxellensis in fermentative environments. Therefore, the regulation of nitrate assimilatory genes YNTI, YNRI, and YNI1 responds to a nitrate-dependent mechanism as well as to a TOR-dependent mechanism. These findings expand the understanding of the regulation of nitrogen metabolism in D. bruxellensis, providing valuable information that may aid in the development of future strategies for its use as an industrial yeast. Full article

► Show Figures

Graphical abstract

33 pages, 1710 KiB

Open AccessSystematic Review

Promoting Sustainable Transport: A Systematic Review of Walking and Cycling Adoption Using the COM-B Model

by Hisham Y. Makahleh, Madhar M. Taamneh and Dilum Dissanayake

Future Transp. 2025, 5(3), 79; https://doi.org/10.3390/futuretransp5030079 - 1 Jul 2025

Abstract

Walking and cycling, as active modes of transportation, play a vital role in advancing sustainable urban mobility by reducing emissions and improving public health. However, widespread adoption faces challenges such as inadequate infrastructure, safety concerns, socio-cultural barriers, and policy limitations. This study systematically [...] Read more.

Walking and cycling, as active modes of transportation, play a vital role in advancing sustainable urban mobility by reducing emissions and improving public health. However, widespread adoption faces challenges such as inadequate infrastructure, safety concerns, socio-cultural barriers, and policy limitations. This study systematically reviewed 56 peer-reviewed articles from 2004 to 2024, across 30 countries across five continents, employing the Capability, Opportunity and Motivation-Behaviour (COM-B) framework to identify the main drivers of walking and cycling behaviours. Findings highlight that the lack of dedicated infrastructure, inadequate enforcement of road safety measures, personal and traffic safety concerns, and social stigmas collectively hinder active mobility. Strategic interventions such as developing integrated cycling networks, financial incentives, urban planning initiatives, and behavioural change programs have promoted increased engagement in walking and cycling. Enhancing urban mobility further requires investment in pedestrian and cycling infrastructure, improved integration with public transportation, the implementation of traffic-calming measures, and public education campaigns. Post-pandemic initiatives to establish new pedestrian and cycling spaces offer a unique opportunity to establish enduring changes that support active transportation. The study suggests expanding protected cycling lanes and integrating pedestrian pathways with public transit systems to strengthen safety and accessibility. Additionally, leveraging digital tools can enhance mobility planning and coordination. Future research is needed to explore the potential of artificial intelligence in enhancing mobility analysis, supporting the development of climate-resilient infrastructure, and informing transport policies that integrate gender perspectives to better understand long-term behavioural changes. Coordinated policy efforts and targeted investments can lead to more equitable transportation access, support sustainability goals, and alleviate urban traffic congestion. Full article

► Show Figures

Figure 1

29 pages, 5986 KiB

Open AccessArticle

How Humans Evaluate AI Systems for Person Detection in Automatic Train Operation: Not All Misses Are Alike

by Romy Müller

Future Transp. 2025, 5(3), 78; https://doi.org/10.3390/futuretransp5030078 - 1 Jul 2025

Abstract

If artificial intelligence (AI) is to be applied in safety-critical domains, its performance needs to be evaluated reliably. The present study investigated how humans evaluate AI systems for person detection in automatic train operation. In three experiments, participants viewed image sequences of people [...] Read more.

If artificial intelligence (AI) is to be applied in safety-critical domains, its performance needs to be evaluated reliably. The present study investigated how humans evaluate AI systems for person detection in automatic train operation. In three experiments, participants viewed image sequences of people moving in the vicinity of railway tracks. A simulated AI system highlighted all detected people—sometimes correctly and sometimes not. Participants had to provide a numerical rating of the AI’s performance and then verbally explain their rating. The experiments manipulated several factors that might influence human ratings: the types and plausibility of AI mistakes, the number of affected images, the number of people present in an image, the position of people relevant to the tracks, and the methods used to elicit human evaluations. While all these factors influenced human ratings, some effects were unexpected or deviated from normative standards. For instance, the factor with the strongest impact was people’s position relative to the tracks, although participants had explicitly been instructed that the AI could not process such information. Taken together, the results suggest that humans may sometimes evaluate more than the AI’s performance on the assigned task. Such mismatches between AI capabilities and human expectations should be taken into consideration when conducting safety audits of AI systems. Full article

► Show Figures

Figure 1

35 pages, 1399 KiB

Open AccessSystematic Review

Congestion Forecasting Using Machine Learning Techniques: A Systematic Review

by Mehdi Attioui and Mohamed Lahby

Future Transp. 2025, 5(3), 76; https://doi.org/10.3390/futuretransp5030076 - 1 Jul 2025

Abstract

Traffic congestion constitutes a substantial global issue, adversely impacting economic productivity and quality of life, with associated costs estimated at approximately 2% of GDP in various nations. This systematic review investigates the application of machine learning (ML) in traffic congestion forecasting from 2010 [...] Read more.

Traffic congestion constitutes a substantial global issue, adversely impacting economic productivity and quality of life, with associated costs estimated at approximately 2% of GDP in various nations. This systematic review investigates the application of machine learning (ML) in traffic congestion forecasting from 2010 to 2024, adhering to the PRISMA 2020 guidelines. A comprehensive search of three major databases (IEEE Xplore, SpringerLink, and ScienceDirect) yielded 9695 initial records, with 115 studies meeting the inclusion criteria following rigorous screening. Data extraction encompassed methodological approaches, ML techniques, traffic characteristics, and forecasting periods, with quality assessment achieving near-perfect inter-rater reliability (Cohen’s

κ

= 0.89). Deep Neural Networks were the predominant technical approach (47%), with supervised learning being the most prevalent (57%). Classification tasks were the most common (42%), primarily addressing recurrent congestion scenarios (76%) and passenger vehicles (90%). The quality of publications was notably high, with 85% appearing in Q1-ranked journals, demonstrating exponential growth from minimal activity in 2010 to 18 studies in 2022. Significant research gaps persist: reinforcement learning is underutilized (8%), rural road networks are underrepresented (2%), and industry–academia collaboration is limited (3%). Future research should prioritize multimodal transportation systems, real-time adaptation mechanisms, and enhanced practical implementation to advance intelligent transportation systems (ITSs). This review was not registered because it focused on mapping the research landscape rather than intervention effects. Full article

► Show Figures

Figure 1

25 pages, 1264 KiB

Open AccessArticle

Potential Assessment of Electrified Heavy-Duty Trailers Based on the Methods Developed for EU Legislation (VECTO Trailer)

by Stefan Present and Martin Rexeis

Future Transp. 2025, 5(3), 77; https://doi.org/10.3390/futuretransp5030077 - 1 Jul 2025

Abstract

Since 1 January 2024, newly produced heavy-duty trailers are subject to the assessment of their performance regarding CO₂ and fuel consumption according to Implementing Regulation (EU) 2022/1362. The method is based on the already established approach for the CO₂ and energy [...] Read more.

Since 1 January 2024, newly produced heavy-duty trailers are subject to the assessment of their performance regarding CO₂ and fuel consumption according to Implementing Regulation (EU) 2022/1362. The method is based on the already established approach for the CO₂ and energy consumption evaluation of trucks and buses, i.e., applying a combination of component testing and vehicle simulation using the software VECTO (Vehicle Energy Consumption calculation TOol). For the evaluation of trailers, generic conventional towing vehicles in combination with the specific CO₂ and fuel consumption-relevant properties of the trailer, such as mass, aerodynamics, rolling resistance etc., are simulated in the “VECTO Trailer” software. The corresponding results are used in the European HDV CO₂ standards with which manufacturers must comply to avoid penalty payments (2030: −10% for semitrailers and −7.5% for trailers compared with the baseline year 2025). Methodology and legislation are currently being extended to also cover the effects of electrified trailers (trailers with an electrified axle and/or electrically supplied auxiliaries) on CO₂, electrical energy consumption, and electric range extension (special use case in combination with a battery-electric towing vehicle). This publication gives an overview of the developed regulatory framework and methods to be implemented in a future extension of VECTO Trailer as well as a comparison of different e-trailer configurations and usage scenarios regarding their impact on CO₂, energy consumption, and electric range by applying the developed methods in a preliminary potential analysis. Results from this analysis indicate that e-trailers that use small batteries (5–50 kWh) to power electric refrigeration units achieve a CO₂ reduction of 5–10%, depending primarily on battery capacity. In contrast, e-trailers designed for propulsion support with larger batteries (50–500 kWh) and e-axle(s) (50–500 kW) demonstrate a reduction potential of up to 40%, largely determined by battery capacity and e-axle rating. Despite their reduction potential, market acceptance of e-trailers remains uncertain as the higher number of trailers compared with towing vehicles could lead to slow adoption, especially of the more expensive configurations. Full article

► Show Figures

Figure 1

9 pages, 339 KiB

Open AccessArticle

Plyometric Training in Prepubertal Soccer Players: Is It Really Effective for Soccer Performance?

by Edoardo Lo Russo, Matteo Levi Micheli, Andrea Vieri, Pascal Izzicupo and Gabriele Mascherini

Biomechanics 2025, 5(3), 50; https://doi.org/10.3390/biomechanics5030050 - 1 Jul 2025

Abstract

Background/Objectives: Plyometric training is a method of increasing soccer performance which leverages the muscle stretch-shortening cycle. This study aimed to evaluate the safety and effectiveness of plyometric training in prepubertal soccer players. Methods: Twenty-three young athletes (age 9.4 ± 0.3 years) from an [...] Read more.

Background/Objectives: Plyometric training is a method of increasing soccer performance which leverages the muscle stretch-shortening cycle. This study aimed to evaluate the safety and effectiveness of plyometric training in prepubertal soccer players. Methods: Twenty-three young athletes (age 9.4 ± 0.3 years) from an elite club, training three times per week, were enrolled. During one of the weekly training sessions, twelve players formed the experimental group (PLYO), incorporating a 45 min plyometric training component into their routine, while the control group (CON), consisting of eleven players continued with their usual training program. At baseline and after 12 weeks, anthropometric parameters, flexibility, lower limb strength, and agility were assessed. Results: At baseline, no differences were observed between the two groups in anthropometric or physical performance parameters. No injuries occurred during the study. After 12 weeks, both groups showed significant growth and performance improvements. However, the PLYO showed a significantly greater increase in lower limb strength (Δ + 10.7%) compared to the CON (Δ + 6.0%). Conversely, although not statistically significant, agility improvements were greater in the CON (Δ + 12.4%) than in the PLYO (Δ + 8.6%). Conclusions: Plyometric training appears to be a safe and effective method for enhancing lower limb strength in prepubertal athletes. However, this strength gain did not directly translate into greater agility, which may benefit more from sport-specific training during this developmental stage. Full article

(This article belongs to the Collection Locomotion Biomechanics and Motor Control)

► Show Figures

Figure 1

20 pages, 23317 KiB

Open AccessArticle

Land Use and Land Cover (LULC) Mapping Accuracy Using Single-Date Sentinel-2 MSI Imagery with Random Forest and Classification and Regression Tree Classifiers

by Sercan Gülci, Michael Wing and Abdullah Emin Akay

Geomatics 2025, 5(3), 29; https://doi.org/10.3390/geomatics5030029 - 1 Jul 2025

Abstract

The use of Google Earth Engine (GEE), a cloud-based computing platform, in spatio-temporal evaluation studies has increased rapidly in natural sciences such as forestry. In this study, Sentinel-2 satellite imagery and Shuttle Radar Topography Mission (SRTM) elevation data and image classification algorithms based [...] Read more.

The use of Google Earth Engine (GEE), a cloud-based computing platform, in spatio-temporal evaluation studies has increased rapidly in natural sciences such as forestry. In this study, Sentinel-2 satellite imagery and Shuttle Radar Topography Mission (SRTM) elevation data and image classification algorithms based on two machine learning techniques were examined. Random Forest (RF) and Classification and Regression Trees (CART) were used to classify land use and land cover (LULC) in western Oregon (USA). To classify the LULC from the spectral bands of satellite images, a composition consisting of vegetation difference indices NDVI, NDWI, EVI, and BSI, and a digital elevation model (DEM) were used. The study area was selected due to a diversity of land cover types including research forest, botanical gardens, recreation area, and agricultural lands covered with diverse plant species. Five land classes (forest, agriculture, soil, water, and settlement) were delineated for LULC classification testing. Different spatial points (totaling 75, 150, 300, and 2500) were used as training and test data. The most successful model performance was RF, with an accuracy of 98% and a kappa value of 0.97, while the accuracy and kappa values for CART were 95% and 0.94, respectively. The accuracy of the generated LULC maps was evaluated using 500 independent reference points, in addition to the training and testing datasets. Based on this assessment, the RF classifier that included elevation data achieved an overall accuracy of 92% and a kappa coefficient of 0.90. The combination of vegetation difference indices with elevation data was successful in determining the areas where clear-cutting occurred in the forest. Our results present a promising technique for the detection of forests and forest openings, which was helpful in identifying clear-cut sites. In addition, the GEE and RF classifier can help identify and map storm damage, wind damage, insect defoliation, fire, and management activities in forest areas. Full article

► Show Figures

Figure 1

23 pages, 2819 KiB

Open AccessReview

Cataloging Actionable Pharmacogenomic Variants for Indian Clinical Practice: A Scoping Review

by Sacheta Sudhendra Kulkarni, Venkatesh R, Anuradha Das and Gayatri Rangarajan Iyer

J. Xenobiot. 2025, 15(4), 101; https://doi.org/10.3390/jox15040101 - 1 Jul 2025

Abstract

Background: Pharmacogenomics (PGx), a pivotal branch of personalized medicine, studies how genetic variations influence drug responses. Despite its transformative potential, the adoption of PGx in Indian clinical practice faces challenges, such as the lack of population-specific data, evidence-based guidelines, and complexities in interpreting [...] Read more.

Background: Pharmacogenomics (PGx), a pivotal branch of personalized medicine, studies how genetic variations influence drug responses. Despite its transformative potential, the adoption of PGx in Indian clinical practice faces challenges, such as the lack of population-specific data, evidence-based guidelines, and complexities in interpreting genomic reports. Comprehensive datasets tailored to Indian patients are essential to facilitate the integration of PGx into clinical settings. Methodology: The study collates pharmacogenomic data from multiple sources, including essential drugs listed by the World Health Organization (WHO), drugs used in neonatal intensive care units (NICUs), minimum sets of alleles recommended by the Association for Molecular Pathology (AMP), and catalogs the allele frequencies from the IndiGenomes database to address gaps in actionable PGx for the Indian population. Curated datasets were used to identify pharmacogenomic variants relevant to clinical practice. Results: Overall, 24 prime genes are essential for the outcomes of 57 drugs. In adults, 18 genes influence the metabolism of 44 drugs whereas, in pediatric populations, genotypes of 18 genes significantly impact the metabolism of 18 drugs. Two over-the-counter drugs with actionable PGx variants were identified: ibuprofen and omeprazole. These findings emphasize the clinical relevance of PGx for commonly used drugs, underscoring the need for population-specific data. Conclusions: As the data of several Indian human genome projects become available, an overarching need exists to establish and regulate the dynamic actionable PGx in Indian clinical practice. This will facilitate the integration of pharmacogenomic data into healthcare, enabling effective and personalized drug therapies. Full article

(This article belongs to the Topic Phase I and Phase II Xenobiotic-Metabolizing Enzymes: Structure, Function, and Regulation)

► Show Figures

Figure 1

13 pages, 498 KiB

Open AccessArticle

The Work Engagement Among Nurses in an Urban-Based Tertiary Hospital

by Ampan Vimonvattana and Nontawat Benjakul

Nurs. Rep. 2025, 15(7), 241; https://doi.org/10.3390/nursrep15070241 - 1 Jul 2025

Abstract

Background: Work engagement is essential to the well-being of nurses and the quality of health care, particularly in high-demand urban hospital environments in Bangkok. To determine the levels of work engagement—vigor, dedication, and absorption—among nurses in a Thai urban tertiary hospital, and to [...] Read more.

Background: Work engagement is essential to the well-being of nurses and the quality of health care, particularly in high-demand urban hospital environments in Bangkok. To determine the levels of work engagement—vigor, dedication, and absorption—among nurses in a Thai urban tertiary hospital, and to identify associated demographic and occupational predictors. Materials and Methods: A cross-sectional study was conducted among 650 nurses at a tertiary university hospital in Bangkok, Thailand, from February to March 2025. Participants were selected through simple random sampling. They completed an online survey including demographic data and the Utrecht Work Engagement Scale (UWES), which assesses three dimensions of engagement: vigor, dedication, and absorption. To identify the predictors of high engagement levels, chi-square tests and multivariate binary logistic regression were used. Results: Most nurses reported low engagement across all dimensions: 73.1% for vigor, 69.1% for dedication, and 70.0% for absorption. In the adjusted models, monthly income was a significant predictor of higher vigor and dedication, whereas no significant predictors emerged for absorption. Other variables, including age, experience, and professional rank, were significant in the bivariate analyses but not in the multivariate models. Conclusions: Nurse engagement remains suboptimal in the urban tertiary hospital setting, with financial compensation emerging as a key determinant. Strategic interventions to improve income equity and career development may help enhance engagement and retention in the nursing workforce. Full article

27 pages, 5866 KiB

Open AccessArticle

Modeling Streamflow Response to Climate Scenarios in Data-Scarce Mediterranean Catchment: The Medjerda in Northern Tunisia

by Khouloud Gader, Ahlem Gara, Slaheddine Khlifi and Marnik Vanclooster

Earth 2025, 6(3), 68; https://doi.org/10.3390/earth6030068 - 1 Jul 2025

Abstract

This study aimed to evaluate the performance and robustness of the GR2m “Génie Rural à 2 paramètres au pas du temps Mensuel” rainfall–runoff model for simulating streamflow under past and future hydrometeorological shifts in the Medjerda, a data-scarce Mediterranean catchment in northern Tunisia [...] Read more.

This study aimed to evaluate the performance and robustness of the GR2m “Génie Rural à 2 paramètres au pas du temps Mensuel” rainfall–runoff model for simulating streamflow under past and future hydrometeorological shifts in the Medjerda, a data-scarce Mediterranean catchment in northern Tunisia characterized by limited hydrometeorological records and high climate variability. The evaluation was conducted across three subcatchments characterized by contrasting climatic conditions and representing the hydrometeorological pattern of the Medjerda catchment. To assess the model’s robustness, a calibration–validation process was applied. This method alternated between dry and wet periods and evaluated model performance through various criteria. Subsequently, GR2m was adopted to simulate projected discharge, using projections from the “Model for Interdisciplinary Research on Climate 5” (MIROC5) under Representative Concentration Pathway (RCP4.5 and RCP8.5) scenarios. Standardized climate indices (SCIs) were employed to assess climate change impacts. The results demonstrate that GR2m performs well in simulating streamflow across different climatic conditions within the Medjerda catchment and maintains satisfactory performance when calibrated over a non-stationary climate period. The findings indicate a continuous decline in projected runoff and suggest a significant increase in extreme drought events. Full article

(This article belongs to the Topic Climate Change and Human Impact on Freshwater Water Resources: Rivers and Lakes)

► Show Figures

Figure 1

25 pages, 1514 KiB

Open AccessReview

Towards Sustainable Scaling-Up of Nanomaterials Fabrication: Current Situation, Challenges, and Future Perspectives

by Mouad Hachhach, Sanae Bayou, Achraf El Kasmi, Mohamed Zoubair Saidi, Hanane Akram, Mounir Hanafi, Ouafae Achak, Chaouki El Moujahid and Tarik Chafik

Eng 2025, 6(7), 149; https://doi.org/10.3390/eng6070149 - 1 Jul 2025

Abstract

Nanomaterials are present everywhere today and represent the new industrial revolution. Depending on the application, there are many ways to synthesize nanomaterials with different properties. The industrial production of nanomaterials faces various challenges at different stages, going from conception and design to implementation [...] Read more.

Nanomaterials are present everywhere today and represent the new industrial revolution. Depending on the application, there are many ways to synthesize nanomaterials with different properties. The industrial production of nanomaterials faces various challenges at different stages, going from conception and design to implementation and scaling-up of the production process, which can limit the growth of practical application at a large-scale scope, such as due to the lack of reproducibility, safety, and environmental impact. Here, we discuss current advances achieved for nanomaterial production at a large scale, encompassing a range of synthetic strategies and post-treatment modifications used to enhance the nanomaterials’ performance. A particular interest is devoted to highlighting the progress of MoS₂ nanomaterials’ application. Thus, overcoming those discussed challenges becomes a new prospect for the future perspectives of industrial nanomaterials and nanotechnologies. Full article

(This article belongs to the Section Materials Engineering)

► Show Figures

Figure 1

17 pages, 741 KiB

Open AccessArticle

Analysis of the Association Between Symptoms of Inattention and Hyperactivity–Impulsivity and Substance Abuse in University Students

by Desirée Ibáñez-Tejedor and Omar Cauli

Psychiatry Int. 2025, 6(3), 78; https://doi.org/10.3390/psychiatryint6030078 - 1 Jul 2025

Abstract

Background and objectives. Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) are frequently present in university students, even without a clinical diagnosis, and may be aggravated by various factors. This study analyzes the relationship between these symptoms and the use of alcohol, tobacco, cannabis, [...] Read more.

Background and objectives. Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) are frequently present in university students, even without a clinical diagnosis, and may be aggravated by various factors. This study analyzes the relationship between these symptoms and the use of alcohol, tobacco, cannabis, and other drugs by young university students. Materials and methods. A cross-sectional study was conducted with 397 university students using an anonymous online questionnaire. ADHD symptoms were assessed with the Adult ADHD Self-Report Scale (ASRS), alcohol use with the Alcohol Use Disorders Identification Test (AUDIT-C), nicotine dependence with the Fagerström test, cannabis use with the Cannabis Abuse Screening Test (CAST), and the use of other substances with an adaptation of the latter. Results. The mean age was 21.4 years, and most participants (76.6%) were women. Of the participants, 46.1% presented symptoms compatible with ADHD according to the ASRS. The most frequent items were difficulty maintaining attention during boring tasks (77.3%), avoiding tasks that require mental effort (76.8%), and being easily distracted by noise or external activity (73.8%). Significant differences were found between ASRS scores and gender, with scores being higher and more consistent among those students who identified themselves as non-binary gender (male or female) (p < 0.01). A significant association was also found between smoking and a higher ASRS score (p < 0.01). Although no significant associations with body mass index were detected, a trend toward greater symptomatology was observed in obese individuals. In multivariate analysis, still gender and smoking significantly (p = 0.12 and p = 0.031, respectively) predicted ADHD symptoms (ASRS score). The model R = 0.228 (R squared = 0.052, F = 1.62, p = 0.077). No statistically significant differences were found between ADHD symptoms and the use of alcohol, cannabis, or other substances in either bivariate or multivariate analyses. Conclusions. This study underscores the importance of early detection of ADHD symptoms in the university setting, considering factors such as gender and smoking habit. Future research should focus on aggravating factors such as academic stress and problematic technology use. Full article

► Show Figures

Figure 1

17 pages, 3453 KiB

Open AccessArticle

An Interdisciplinary Perspective of the Karst Springs’ Areas as Drinking Water: Perusal from Northeastern Slovenia

by Natalija Špeh and Anja Bubik

Pollutants 2025, 5(3), 19; https://doi.org/10.3390/pollutants5030019 - 1 Jul 2025

Abstract

Karst aquifer systems are highly vulnerable due to their unique underground water flow characteristics, making them prone to contamination and abandonment. This study compares an active karst water source (Ljubija) with a previously abandoned one (Rečica) to assess freshwater quality and water protection [...] Read more.

Karst aquifer systems are highly vulnerable due to their unique underground water flow characteristics, making them prone to contamination and abandonment. This study compares an active karst water source (Ljubija) with a previously abandoned one (Rečica) to assess freshwater quality and water protection risks, especially as water scarcity becomes a concern during dry summer periods. The Ljubija and Rečica catchments, designated as water protection areas (WPAs), were monitored over a year (January–December 2020). Groundwater (GW) and surface water (SW) were analyzed twice a month during both dry and wet periods, adhering to European and national guidelines. An interdisciplinary approach integrated natural and human impact indicators, linking water quality to precipitation, hydrogeography, and landscape characteristics. After Slovene regulation standards (50 mg/l), the Ljubija source demonstrated stable water quality, with low nitrate levels (average 2.6 mg/l) and minimal human impact. In contrast, the Rečica catchment was more vulnerable, with its GW excluded from drinking use since the 1990s due to organic contamination, worsened by the area’s karst hydrogeology. In 2020, its nitrate concentration averaged 6.0 mg/l. These findings highlight the need for improved monitoring regulations, particularly for vulnerable karst water sources, to safeguard water quality and ensure sustainable use. Full article

21 pages, 3151 KiB

Open AccessArticle

Influence and Potential of Additive Manufactured Reference Geometries for Ultrasonic Testing

by Stefan Keuler, Anne Jüngert, Martin Werz and Stefan Weihe

J. Manuf. Mater. Process. 2025, 9(7), 224; https://doi.org/10.3390/jmmp9070224 - 1 Jul 2025

Abstract

This study researches and discusses the impact of different manufacturing-induced effects of additive manufacturing (AM), such as anisotropy on sound propagation and attenuation, on the production of test specimens for ultrasonic testing (UT). It was shown that a linear, alternating hatching pattern led [...] Read more.

This study researches and discusses the impact of different manufacturing-induced effects of additive manufacturing (AM), such as anisotropy on sound propagation and attenuation, on the production of test specimens for ultrasonic testing (UT). It was shown that a linear, alternating hatching pattern led to strong anisotropy in sound velocity and attenuation, with a deviation in sound velocity and gain of over 840 m/s and 9 dB, depending on the measuring direction. Furthermore, it was demonstrated that the build direction exhibits distinct acoustic properties. The influence of surface roughness on both the reflector and coupling surfaces was analyzed. It was demonstrated that post-processing of the reflector surface is not necessary, as varying roughness levels did not significantly change the signal amplitude. However, for high frequencies, pre-treatment of the coupling surface can improve sound transmission up to 6 dB at 20 MHz. Finally, the reflection properties of flat bottom holes (FBH) in reference blocks produced by AM and electrical discharge machining (EDM) were compared. The equivalent reflector size (ERS) of the FBH, which refers to the size of an idealized defect with the same ultrasonic reflection behavior as the measured defect, was determined using the distance gain size (DGS) method—a method that uses the relationship between reflector size, scanning depth, and echo amplitude to evaluate defects. The findings suggest that printed FBHs achieve an improved match between the ERS and the actual manufactured reflector size with a deviation of less than 13%, thereby demonstrating the potential for producing standardized test blocks through additive manufacturing. Full article

(This article belongs to the Special Issue Advanced Welding Processes, Additive Manufacturing and Numerical Models: 2nd Edition)

► Show Figures

Figure 1

Recent Articles

Open Access Journals

Highly Accessed Articles

Latest Books

News

Blog Posts

Topics

Selected Special Issues

Selected Collections

Journals by Subject

Further Information

Guidelines

MDPI Initiatives

Follow MDPI