16168 research outputs found
Sort by
Influence of the presence of surface cracks on the dynamic response and failure of pipes under pipe whip conditions /
No full textThis study investigates the influence of cracks, of semi-elliptical shape according to ASME III rules, which is assumed be located near the pipe region where tensile stress is expected. The investigation refers to pipe whip conditions. Pipe whips are a high-energy phenomenon resulting from sudden rupture in pressurized piping systems and poses a significant threat to structural integrity and safety. This research focuses on how the presence of semi-elliptical cracks alters stress distribution, deformation and failure modes during such dynamic accidental events. With the applications of numerical simulations and principles of fracture mechanics, the manuscript presents the interaction between crack geometry, pipe curvature, and dynamic loading conditions. Key findings include the amplification of stress intensity factors in the cracked regions which exacerbate local plastic deformation due to their curvature under whipping forces. Additionally, this study highlights the critical role of crack dimensions and orientation in determining failure and provides insights into the energy dissipation caused by such defect. The results will contribute to the advancement of understanding of pipe behaviour during the postulated accident scenario. Moreover, insight could allow to enhance predictive models for pipe failure assessment and adopt design strategies for mitigating risks associated with pipe whip. This study significantly enhances pipeline safety by rigorously integrating fracture mechanics into dynamic response modelling, providing a comprehensive basis for strengthening the structural robustness of piping systems operating under high-energy dynamic loads
Determinants of sustainability-oriented innovations in the textile and fashion supply chain /
No full textEU Green Deal and related regulations require the textile and fashion industries to adopt sustainable business practices and innovative solutions. The European Commission’s Circular Economy Action Plan identifies the textile and fashion sector as one of seven key industries necessitating strategic sustainability transitions aligned with the Sustainable Development Goals (SDGs) and broader global challenges. In response, companies in this sector are increasingly implementing measures related to sustainable production and consumption, reducing water usage, ensuring fair labour practices, adopting sustainable managerial approaches, and fostering sustainability-oriented innovations within their supply chains. Despite growing global attention to sustainability, research on sustainability-oriented innovation (SOI) and circular supply chains in this industry remains fragmented. Therefore, this study aims to analyse the determinants of SOI in the textile and fashion supply chains. A synthetic literature review was employed to examine the key factors influencing the implementation of the SOI. The analysis identified three main categories of factors affecting SOI in supply chains: internal organizational factors, market- and consumer-driven elements, and regulatory and policy drivers. These determinants collectively support companies in pursuing SOI as a pathway to sustainable value creation. The study is grounded in the development of a conceptual model and contributes to both sustainability research and the application of the triple bottom lineapproach. This research offers two main contributions: first, it provides a comprehensive understanding of sustainability-oriented innovations within supply chains; second, it proposes a structured framework to examine the drivers of SOI in the textile and fashion industry. The findings serve as a foundation for future empirical studies and offer insights for stakeholders interested in advancing sustainable supply chain innovation
Model-based evaluation of connexin hemichannel permeability /
No full textConnexin (Cx) hemichannels form intercellular gap junction channels but can also function independently. These large-pore channels are permeable not only to ions but also to small signalling molecules and metabolites. This functional property is relevant to many physiological processes and can be altered by various biochemical factors or disease-causing mutations. In this study, we present a methodology for quantifying and comparing the permeabilities of hemichannels formed by different Cx isoforms using a combination of fluorescence imaging, electrophysiological recordings and mathematical modelling. Fluorescence imaging, coupled with mathematical modelling based on Fick’s law and/or the Goldman-Hodgkin-Katz current equation, enables assessment of tracer diffusion rates. These data are integrated with independently obtained electrophysiological measurements of hemichannel activity into a unified statistical model based on the likelihood ratio test. Simulation-based analyses demonstrate that this approach can reliably detect differences as low as two-fold in hemichannel permeability using datasets of moderate size (n < 100). Crucially, this approach requires only a minimal amount of time-intensive electrophysiological recording and leverages higher-throughput fluorescence measurements, which can be further streamlined using computational tools for automated cell detection and data extraction. We apply this methodology to compare the permeability of hemichannels formed by wild-type Cx26 and a pore-lining variant, Cx26⁎A49E. Our results show a significant increase in DAPI permeability in Cx26⁎A49E hemichannels, consistent with previous findings. This methodology can be extended to assess the permeabilities of other large-pore channels
Energy-saving method for nearby wireless battery-powered trackers based on their cooperation /
No full textThe tracking of assets or cargo is one of the main objectives of global logistics and transportation systems, ensuring operational efficiency, security, and timeliness. Currently, battery-operated GPS (Global Positioning System)-based tracking devices are used for this purpose. The main shortcoming of these devices is the lifetime of the batteries because they cannot be replaced or recharged, or because this is simply not economically feasible. Therefore, efficient methods are needed to prolong battery life as much as possible. Various existing energy-saving techniques can be applied to solve this problem. However, none of these consider situations in which multiple tracking devices are transported together and can cooperate to further increase their energy efficiency. In this study, we propose and evaluate the novel lightweight peer-to-peer energy-saving method for nearby wireless battery-powered trackers based on their cooperation. The proposed method is based on the short-range BLE (Bluetooth Low Energy) device discovery mechanism and the dynamic election of the leader tracker (with the highest battery capacity) to report the location of its own and other neighboring trackers to the central server. The experimental evaluation of the proposed method shows that, compared to the traditional approach, where each tracker sends its location individually, the proposed method allows a reduction in the average battery charge required for one position report from 19% to 240% per each cooperating tracker. The average energy consumption for one location report per node decreased from 4.68 mWh using the traditional approach to 3.93 mWh for 2 cooperating devices and 1.92 mWh for 15 cooperating devices
Retrograde versus orthograde obturation in relation to root resection: evaluation of microhardness of mineral trioxide aggregate in vitro /
No full textLimited visibility of the operating field can lead to difficulties in relation to adequate retrograde filling during periapical surgery in specific clinical situations. Solid and homogenic root filling material that does not need to be removed after apicoectomy could be used as an alternative to retrograde filling. This study aims to compare the micro-hardness of mineral trioxide aggregate (MTA) considering retrograde vs. orthograde obturation during root end resection in vitro. Methods: 20 roots of maxillary incisors were chemo-mechanically prepared and divided into 2 groups: group A (n = 10)—retrograde filling and group B (n = 10)—orthograde filling. The specimens of group A were filled with gutta-percha and resin-based sealer, 3 mm of the apical area were removed after the incubation period. Retrograde cavities of a depth of 3 mm were made and filled with MTA. In group B, apical 7 mm of the roots was filled with MTA in an orthograde manner. After the incubation, 3 mm of the root ends were removed. Vickers microhardness test was applied to the MTA No statistically significant difference in micro-hardness between groups was found (p > 0.05). The assessment of retrograde filling did not reveal significant differences of MTA micro-hardness in different parts of the material (p > 0.05). The assessment of orthograde filling revealed that MTA micro-hardness 3 mm from the apex was significantly higher when compared to the distance of 1 and 2 mm from the root apex (p > 0.05). The obturation method did not affect the hardness of MTA during root end resection in vitro
Prognostic models for depression and post-traumatic stress disorder symptoms following traumatic brain injury: a CENTER-TBI study /
No full textBackground Traumatic brain injury (TBI) is associated with an increased risk of major depressive disorder (MDD) and post-traumatic stress disorder (PTSD). We aimed to identify predictors and develop models for the prediction of depression and PTSD symptoms at 6 months post-TBI. Methods We analysed data from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury study. We used linear regression to model the relationship between predictors and depression (Patient Health Questionnaire-9) and PTSD symptoms (PTSD Checklist for Diagnostic and Statistical Manual for Mental Health Disorders Fifth Edition). Predictors were selected based on Akaike's Information Criterion. Additionally, we fitted logistic models for the endpoints 'probable MDD' and 'probable PTSD'. We also examined the incremental prognostic value of 2-3 weeks of symptoms. Results We included 2163 adults (76% Glasgow Coma Scale=13-15). Depending on the scoring criteria, 7-18% screened positive for probable MDD and about 10% for probable PTSD. For both outcomes, the selected models included psychiatric history, employment status, sex, injury cause, alcohol intoxication and total injury severity; and for depression symptoms also preinjury health and education. The performance of the models was modest (proportion of explained variance=R 2 8% and 7% for depression and PTSD, respectively). Symptoms assessed at 2-3 weeks had a large incremental prognostic value (delta R 2 =0.25, 95% CI 0.24 to 0.26 for depression symptoms; delta R 2 =0.30, 95% CI 0.29 to 0.31 for PTSD). Conclusion Preinjury characteristics, such as psychiatric history and unemployment, and injury characteristics, such as violent injury cause, can increase the risk of mental health problems after TBI. The identification of patients at risk should be guided by early screening of mental health
Assessing borehole thermal energy storage patterns for renewable heating solutions /
No full textAs the global energy transition advances, the heating sector accounted for approximately 51% of energy consumption in 2023, predominantly relying on fossil fuels. Renewable energy sources, including solar power, wind, and thermal energy, offer promising alternatives but face challenges with large-scale, longterm energy storage to balance the intermittent supply with heating demand. Borehole Thermal Energy Storage (BTES) presents a highly suitable option for addressing seasonal mismatches between energy supply and demand
Enhanced human-robot teaming through attention multi convolutional neural network-based multi-modal sensor fusion for hand gesture recognition and orientation control /
No full textOur study aims at enhancing Human-Robot Interaction, Collaboration, and Teaming (HRI/C/T) in industrial automation by developing a novel framework for real-time gesture control of a robotic hand. We use an Inertial Measurement Unit (IMU) sensor for precise orientation control of the end effector, and surface Electromyography (sEMG) sensors to detect muscle movements. The sEMG signals are processed by an Attention-based Multi Convolutional Neural Network (A-MCNN) for accurate gesture detection, enabling the robotic hand to mimic these gestures in real-time. Our method achieves notable results for gesture recognition, with the A-MCNN model attaining an accuracy of 97.89%, a precision of 97.49%, a recall of 97.71%, and an F1 score of 97.65%. This integration of IMU and sEMG technologies with advanced neural networks creates a responsive and intuitive control mechanism, improving safety, usability, and interaction of collaborative robots in shared workspaces. Our approach aims to transition towards Human-Robot Teaming (HRT), significantly advancing the seamless and safe integration of robots in industrial environments, enhancing productivity and collaboration
Femtosecond laser treatment of copper current collectors and their application in Li-ion batteries /
No full textCurrent collectors (CCs) play an important role in enhancing the electrochemical performance of lithium-ion batteries (LiB). Research shows that increasing the surface roughness of copper foil helps improve the bonding strength between the current collector and the active material, reduces the contact resistance between them, and consequently enhances the battery’s rate discharge performance and cycling stability. In the present work, a copper current collector modification by femtosecond laser treatment forming quasiperiodical nanostructures was proposed. The modified current collectors were examined through scanning electron microscopy (SEM) imaging and roughness measurements and further tested with silicon particles in Li-ion cells through galvanostatic charge/discharge experiments. As a result of the laser process, one can observe increasing contact between the current collector and the active material grains, which creates a buffer zone for the volume expansion of the active material during charging and discharging. The results show increased specific capacities, cyclabilities, and Coulombic efficiencies for modified current collectors compared with standard copper foil. It was demonstrated that implementing laser treatment into standard procedures of electrode manufacturing for lithium-ion batteries can easily improve the electrochemical performance of active materials, especially those that experience large volume changes during cycling