Publikační činnost Děkanátu FEI / Publications of the Dean's Office of the Faculty of Electrical Engineering and Computer Science (400)

Permanent URI for this collectionhttp://hdl.handle.net/10084/151870

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Děkanátu FEI (400) v časopisech registrovaných ve Web of Science od roku 2023 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

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Now showing 1 - 20 out of 94 results

Allotrope-dependent activity-stability relationships of molybdenum sulfide hydrogen evolution electrocatalysts
(Springer Nature, 2024) Escalera-López, Daniel; Iffelsberger, Christian; Zlatar, Matej; Novčić, Katarina; Maselj, Nik; Van Pham, Chuyen; Jovanovič, Primož; Hodnik, Nejc; Thiele, Simon; Pumera, Martin; Cherevko, Serhiy
Molybdenum disulfide (MoS2) is widely regarded as a competitive hydrogen evolution reaction (HER) catalyst to replace platinum in proton exchange membrane water electrolysers (PEMWEs). Despite the extensive knowledge of its HER activity, stability insights under HER operation are scarce. This is paramount to ensure long-term operation of Pt-free PEMWEs, and gain full understanding on the electrocatalytically-induced processes responsible for HER active site generation. The latter are highly dependent on the MoS2 allotropic phase, and still under debate. We rigorously assess these by simultaneously monitoring Mo and S dissolution products using a dedicated scanning flow cell coupled with downstream analytics (ICP-MS), besides an electrochemical mass spectrometry setup for volatile species analysis. We observe that MoS2 stability is allotrope-dependent: lamellar-like MoS2 is highly unstable under open circuit conditions, whereas cluster-like amorphous MoS3-x instability is induced by a severe S loss during the HER and undercoordinated Mo site generation. Guidelines to operate non-noble PEMWEs are therefore provided based on the stability number metrics, and an HER mechanism which accounts for Mo and S dissolution pathways is proposed.
Performance prediction of power beacon-aided wireless sensor-powered non-orthogonal multiple-access Internet-of-Things networks under imperfect channel state information
(MDPI, 2024) Nguyen, Ngoc-Long; Le, Anh-Tu; Nguyen, Phuong-Loan T.; Minh, Bui Vu; Rejfek, Luboš; Kim, Yong-Hwa
In this paper, we investigate a novel power beacon (PB)-aided wireless sensor-powered non-orthogonal multiple-access (NOMA) Internet-of-Things (IoT) network under imperfect channel state information (CSI). Furthermore, the exact expression outage probability (OP) of two IoT users is derived to analyze the performance of the considered network. To give further insight, the expression asymptotic OP and diversity order are also expressed when the transmit power at the PB goes to infinity. Furthermore, a deep neural network (DNN) framework is proposed to concurrently forecast IoT users' OP in relation to real-time setups for IoT users. Additionally, when compared to the traditional analysis, our created DNN shows the shortest run-time prediction, and the outcomes predicted by the DNN model almost match those of the simulation. In addition, numerical results validate our analysis, simulation, and prediction through a Monte Carlo Simulation. Furthermore, the results show the impact of the main parameter on our proposed system. Finally, these findings show that NOMA performs better than the conventional orthogonal multiple-access (OMA) techniques.
Multiscale hierarchical nanoarchitectonics with stereographically 3D-printed electrodes for water splitting and energy storage
(Elsevier, 2024) Subhadarshini, Suvani; Ghosh, Kalyan; Pumera, Martin
The pursuit of sustainable solutions to address the global energy crisis has led to a keen interest in the advancement of cost-effective and multifunctional electrochemical systems. These systems aim to achieve both zero -carbon emissions and the dual capability to convert and store energy ef ficiently. The electrochemical splitting of water is one way to create carbon -neutral, clean hydrogen gas. Electrocatalysis and hydrogen evolution in general depends not only on the catalyst but also on its nano- and microstructure, which in fluences local chemical conditions and hydrogen gas bubble detachment. Therefore, rapid screening of not only potential catalysts but also various structured surfaces is needed for effective electrode fabrication. The fused deposition modeling (FDM) method of 3D printing is frequently used for electrode fabrication using conducting filaments; however, its micro-structuration resolution is limited. Stereolithography can produce complex and fine structures; however, the resins are not conductive and therefore the structures are not suitable for electrode fabrication. In this work, we have fabricated a substrate with highresolution needle array architecture using stereolithographic (SLA) 3D printing and coated it with Co 3 Te 4 - CoTe 2 (COT) nano fiber for water splitting and energy storage. The SLA 3D -printed cobalt telluride electrodes showed appreciable performance as a photoelectrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), acting as a bifunctional catalyst. We also demonstrated fabrication of a cobalt telluride based SLA 3D -printed supercapacitor device with multiscale hierarchy. The SLA 3D -printed supercapacitor device exhibited good electrochemical behavior along with high cycling stability. In general, we show here a universal method for SLA conductive electrode fabrication with hierarchical structuring of functional elements and suitable for various applications.
Comparing conventional physician-led education with VR education for pacemaker implantation: A randomized study
(MDPI, 2024) Drozdová, Adéla; Poloková, Karin; Jiravský, Otakar; Jiravská Godula, Bogna; Chovančík, Jan; Ranič, Ivan; Jiravský, Filip; Hečko, Jan; Škňouřil, Libor
Introduction: Education of patients prior to an invasive procedure is pivotal for good cooperation and knowledge retention. Virtual reality (VR) is a fast-developing technology that helps educate both medical professionals and patients. Objective: To prove non-inferiority of VR education compared to conventional education in patients prior to the implantation of a permanent pacemaker (PPM). Methods: 150 participants scheduled for an elective implantation of a PPM were enrolled in this prospective study and randomized into two groups: the VR group (n = 75) watched a 360 degrees video about the procedure using the VR headset Oculus Meta Quest 2, while the conventional group (n = 75) was educated by a physician. Both groups filled out a questionnaire to assess the quality of education pre- and in-hospital, their knowledge of the procedure, and their subjective satisfaction. Results: There was no significant difference in the quality of education. There was a non-significant trend towards higher educational scores in the VR group. The subgroup with worse scores was older than the groups with higher scores (82 vs. 76 years, p = 0.025). Anxiety was reduced in 92% of participants. Conclusion: VR proved to be non-inferior to conventional education. It helped to reduce anxiety and showed no adverse effects.
Nanoarchitectonics of laser induced MAX 3D-printed electrode for photo-electrocatalysis and energy storage application with long cyclic durability of 100 000 cycles
(Wiley, 2024) Nouseen, Shaista; Deshmukh, Sujit; Pumera, Martin
3D printing, a rapidly expanding domain of additive manufacturing, enables the fabrication of intricate 3D structures with adjustable fabrication parameters and scalability. Nonetheless, post-fabrication, 3D-printed materials often require an activation step to eliminate non-conductive polymers, a process traditionally achieved through chemical, thermal, or electrochemical methods. These conventional activation techniques, however, suffer from inefficiency and inconsistent results. In this study, a novel chemical-free activation method employing laser treatment is introduced. This innovative technique effectively activates 3D-printed electrodes, which are then evaluated for their photo and electrochemical performance against traditional solvent-activated counterparts. The method not only precisely ablates surplus non-conductive polymers but also exposes and activates the underlying electroactive materials. The 3D-printed electrodes, processed with this single-step laser approach, exhibit a notably low overpotential of approximate to 505 mV at a current density of -10 mA cm(-2) under an illumination wavelength of 365 nm. These electrodes also demonstrate exceptional durability, maintaining stability through >100 000 cycles in energy storage applications. By amalgamating 3D printing with laser processing, the creation of electrodes with complex structures and customizable properties is enabled. This synergy paves the way for streamlined production of such devices in the field of energy conversion and storage.
Complexity-based analysis of the variations in the brain response of porn-addicted and healthy individuals under different function tasks
(World Scientific Publishing Co Pte Ltd, 2024) Pakniyat, Najmeh; Ramadoss, Janarthanan; Karthikeyan, Anitha; Penhaker, Marek; Krejcar, Ondřej; Namazi, Hamidreza
The examination of brain responses in individuals with a pornography addiction compared to those without sheds light on the neurobiological aspects associated with this behavior. Neuroscientific studies utilizing techniques such as electroencephalography (EEG) have shown that porn-addicted individuals may exhibit alterations in neural pathways related to reward processing and impulse control. In this paper, we analyzed the variations in the brain response of porn-addicted versus healthy individuals under five function tasks including baseline, emotional state, memorize task, executive task, and recall task. For this purpose, we analyzed the complexity of EEG signals using fractal theory, approximate entropy (ApEn), and sample entropy. The results showed that the EEG signals of porn-addicted teenagers are more complex than the ones for healthy individuals, which reflects a higher level of brain activity for porn-addicted teenagers. This method of analysis can be extended to examine the brain activity of other types of addiction versus healthy brains.
Downsizing nanoarchitectonics of multilayered MXenes electrocatalysts towards real time ion tracking via EQCM and electrocatalytic applications
(Elsevier, 2024) Padinjareveetil, Akshay Kumar K.; Pumera, Martin
Since their discovery, engineering two-dimensional (2D) MXene materials have attracted rapid interest in both energy storage and conversion applications. Among the several techniques being introduced for enhancing material properties, downsizing is one among the interesting approaches. Downsizing involves the deliberate scaling down of active 2D materials, such as MXenes, systematically. Although major studies are focused on the electrochemical applications of single layered MXene flakes, curiosity in evaluating the downsized multilayered MXenes for electrochemical applications motivates this project. Thus, in the current study, the multilayered bulk MXenes are sequentially stepped down to smaller multilayered fragments at definite time intervals, and subsequently the potential of this procured heterogeneous polydispersed solution are evaluated towards electrochemical applications without any further post -treatments. Real time monitoring of lithium -ion exchange in the downsized MXene materials at various time intervals was tracked using the electrochemical quartz crystal microbalance technique, where the downsized MXene system exhibited water -assisted lithium -ion transfer behavior. Increase in mass exchange was found to increase with increase in downsized MXene systems, thus making it very interesting towards ion storage applications. Further, downsized MXene electrocatalyst material delivered the lowest onset potential for hydrogen production among the set of catalysts studied. In short, this study outlines and pioneers some interesting observations regarding both energy storage and catalytic applications of multilayered downsized MXenes, thereby opening up new possibilities for facile, rapid and cost-effective material fabrication approaches.
Analysis on fetal phonocardiography segmentation problem by hybridized classifier
(Elsevier, 2024) Kong, Lingping; Barnová, Kateřina; Jaroš, René; Mirjalili, Seyedali; Snášel, Václav; Pan, Jeng-Shyang; Martinek, Radek
Fetal examinations are a significant and challenging field of healthcare. Cardiotocography is the most commonly used method for monitoring fetal heart rate and uterine contractions. As a promising alternative to cardiotocography, fetal phonocardiography is beginning to emerge. It is an entirely non-invasive, passive, and low-cost method. However, it is tough to estimate the ideal form of the fetal sound signal in most cases due to the presence of disturbances. The disturbances originate from movements or rotations of the fetal body, making fetal heart sound processing difficult. This study presents an automatic method for segmenting the fetal heart sounds in a phonocardiographic signal that is loaded with different types of disturbances and analyzes which of these disturbances most affect segmentation accuracy. To provide a comprehensive investigation, we propose a hybrid classifier based on Transformer and eXtreme Gradient Boosting, short for XGBoost, to improve segmentation performance by decision -making integration. 2000 segments of data from the Research Resource for Complex Physiologic Signals, PhysioNet repository, and created synthetic data (873 recordings) were used for the experiment. In the S1 label, our proposed method ranks first among all compared algorithms in precision, recall, F1, and accuracy score, tying with Transformer in recall score. It achieves an accuracy increase of 5% and 1.3% compared to XGBoost and Transformer, respectively. Similarly, in the S2 label, there is a precision score increase of 5.8% and 3.7% compared to XGBoost and Transformer, respectively. In general, our proposed method shows effective and promising performance..
A comprehensive analysis of cognitive CAPTCHAs through eye tracking
(IEEE, 2024) Dinh, Nghia; Ogiela, Lidia Dominika; Kiet, Tran-Trung; Tuan, Le-Viet; Hoang, Vinh Truong
CAPTCHA (Completely Automated Public Turing Test to Tell Computers and Humans Apart) has long been employed to combat automated bots. It accomplishes this by utilizing distortion techniques and cognitive characteristics. When it comes to countering security attacks, cognitive CAPTCHA methods have proven to be more effective than other approaches. The advancement of eye-tracking technology has greatly improved human-computer interaction (HCI), enabling users to engage with computers without physical contact. This technology is widely used for studying attention, cognitive processes, and performance. In this specific research, we conducted eye-tracking experiments on participants to investigate how their visual behavior changes as the complexity of cognitive CAPTCHAs varies. By analyzing the distribution of eye gaze on each level of CAPTCHA, we can assess users’ visual behavior based on eye movement performance and process metrics. The data collected is then employed in Machine Learning (ML) algorithms to categorize and examine the relative importance of these factors in predicting performance. This study highlights the potential to enhance any cognitive CAPTCHA model by gaining insights into the underlying cognitive processes.
Single atom engineered materials for sensors
(Elsevier, 2024) Pumera, Martin; Thakkar, Parth
The pursuit of high-performance sensors necessitates the exploration of new materials to realize this potential. Single atom engineering (SAE) is used to plant individual atoms into the appropriate surrounding of (nano)materials in order to confer distinct materials properties. Hence, the nano architectonics principle utilized for single atom engineering allows us to build highly specific, selective, and sensitive sensors, taking these parameters to new and unprecedented levels. Such improvements derive from single atom–material interactions, coordination geometry, and environment, which in turn influence the electronic structure of the implanted atom and its surroundings. In this review, we briefly discuss the preparation and characterization of single atom engineered materials, and focus on their application for gas sensing, chemical sensing in the liquids, and biosensing. Single atom engineered materials offer tunable properties that in many cases enhance signal amplification and selectivity.
Programming self-assembling magnetic microrobots with multiple physical and chemical intelligence
(Elsevier, 2024) Mayorga-Martinez, Carmen C.; Zelenka, Jaroslav; Přibyl, Tomáš; Marzo, Adaris Lopez; Životský, Ondřej; Ruml, Tomáš; Pumera, Martin
Medical microrobots represent the cutting-edge of biomedical research, showcasing their potential as versatile tools. They exhibit promise in acting as carriers for cancer cell therapy, effectively delivering drugs, and as manipulators equipped for biosensing, offering mobility and adaptability. Despite these advancements, the intricate challenge of creating a microrobot that seamlessly integrates various physical and chemical functionalities persists. This includes the fusion of selective sensing, manipulation capabilities, carrier functionality, precise time-based actuators for motion control, and adaptive shaping. Addressing these complexities remains an ongoing endeavor. In this context, our work introduces a pioneering magnetic microrobot founded on CaCO3 microparticles (MPs) synthesized alongside polyethylenimine (CaCO3-PEI), forming the core body. This is combined with Fe3O4 nanoparticles (NPs) enveloped in glutaraldehyde (Fe3O4-Glu), constituting the propulsive engine. The synergy of these elements enables the microrobot to execute multimodal motions, orchestrating its movement with finesse. This dynamic capability follows a “deliver-and-return” pattern for precise targeting applications with real-world relevance. Furthermore, the Fe3O4-Glu/CaCO3-PEI microrobots demonstrated remarkable proficiency in the targeted identification, manipulation, and transportation of cancer cells through the strategic integration of specific antibodies onto their structure. Within the realm of selective cancer cell detection, these microrobots adeptly function as dynamic mobile immunosensors. The versatile utility of the Fe3O4-Glu/CaCO3-PEI microrobots extends to their role as carriers for drugs and imaging agents, facilitated by the mediation of extracellular pH modulation in cancer cells orchestrated by CaCO3. This innovative work introduces a novel “on-the-fly” concept, revolutionizing the landscape of robotics programmed with multifaceted chemical and physical intelligences.
Sarcopenia and adipose tissue evaluation by artificial intelligence predicts the overall survival after TAVI
(Springer Nature, 2024) Pekař, Matej; Jiravský, Otakar; Novák, Jan; Branny, Piotr; Balušík, Jakub; Daniš, Daniel; Hečko, Jan; Kantor, Marek; Prosecký, Robert; Blaha, Lubomír; Neuwirth, Radek
Sarcopenia is a serious systemic disease that reduces overall survival. TAVI is selectively performed in patients with severe aortic stenosis who are not indicated for open cardiac surgery due to severe polymorbidity. Artificial intelligence-assisted body composition assessment from available CT scans appears to be a simple tool to stratify these patients into low and high risk based on future estimates of all-cause mortality. Within our study, the segmentation of preprocedural CT scans at the level of the lumbar third vertebra in patients undergoing TAVI was performed using a neural network (AutoMATiCA). The obtained parameters (area and density of skeletal muscles and intramuscular, visceral, and subcutaneous adipose tissue) were analyzed using Cox univariate and multivariable models for continuous and categorical variables to assess the relation of selected variables with all-cause mortality. 866 patients were included (median(interquartile range)): age 79.7 (74.9–83.3) years; BMI 28.9 (25.9–32.6) kg/m2. Survival analysis was performed on all automatically obtained parameters of muscle and fat density and area. Skeletal muscle index (SMI in cm2/m2), visceral (VAT in HU) and subcutaneous adipose tissue (SAT in HU) density predicted the all-cause mortality in patients after TAVI expressed as hazard ratio (HR) with 95% confidence interval (CI): SMI HR 0.986, 95% CI (0.975–0.996); VAT 1.015 (1.002–1.028) and SAT 1.014 (1.004–1.023), all p < 0.05. Automatic body composition assessment can estimate higher all-cause mortality risk in patients after TAVI, which may be useful in preoperative clinical reasoning and stratification of patients.
Magnetic microrobot swarms with polymeric hands catching bacteria and microplastics in water
(American Chemical Society, 2024) Ussia, Martina; Urso, Mario; Oral, Cagatay M.; Peng, Xia; Pumera, Martin
The forefront of micro- and nanorobot research involves the development of smart swimming micromachines emulating the complexity of natural systems, such as the swarming and collective behaviors typically observed in animals and microorganisms, for efficient task execution. This study introduces magnetically controlled microrobots that possess polymeric sequestrant “hands” decorating a magnetic core. Under the influence of external magnetic fields, the functionalized magnetic beads dynamically self-assemble from individual microparticles into well-defined rotating planes of diverse dimensions, allowing modulation of their propulsion speed, and exhibiting a collective motion. These mobile microrobotic swarms can actively capture free-swimming bacteria and dispersed microplastics “on-the-fly”, thereby cleaning aquatic environments. Unlike conventional methods, these microrobots can be collected from the complex media and can release the captured contaminants in a second vessel in a controllable manner, that is, using ultrasound, offering a sustainable solution for repeated use in decontamination processes. Additionally, the residual water is subjected to UV irradiation to eliminate any remaining bacteria, providing a comprehensive cleaning solution. In summary, this study shows a swarming microrobot design for water decontamination processes.
Magnetic soft centirobot to mitigate biological threats
(Wiley, 2024) Vaghasiya, Jayraj V.; Mayorga-Martinez, Carmen C.; Zelenka, Jaroslav; Sharma, Shelja; Ruml, Tomáš; Pumera, Martin
Soft robots have drawn a lot of interest in the field of human–robot interfaces because they can mimic the propulsion of soft bodies and archive complex tasks that cannot be made by rigid robots such as performing the complex motion, avoiding collisions by absorbing impacts, and shape adaptation by elastic deformation. Herein, drawing inspiration from creatures in the Cambrian period, such as Hallucigenia, we develop a centimeter-sized soft robot with multiple magnetic legs (referred to as a soft centirobot). This robot is equipped with graphitic carbon nitride (g-C3N4) nanosheets to kill biological threats by photogenerated reactive oxygen species under black light illumination. The motion of g-C3N4 soft centirobot is controlled by magnetic actuation even in complex wastewater samples (with a relative speed of 0.12 body lengths per second). The magnetic multilegs work as a propeller to walk across and cover large regions, and water disinfection is more efficient than what could be achieved by nano/micrometer scale sheets of g-C3N4. Finally, factors affecting the accelerated propulsion of g-C3N4 soft centirobot such as design principle, structure geometry, body mass, driving mechanism, and magnetic sensitivity, have been investigated. We envision that such a photoactive 2D material-based integrated centimeter-sized robot shall find application in many areas where pathogen removal is required.
Intelligent magnetic microrobots with fluorescent internal memory for monitoring intragastric acidity
(Wiley, 2024) Senthilnathan, N.; Oral, Cagatay M.; Novobilský, Adam; Pumera, Martin
This study investigates the dynamic ﬂuctuations of pH caused by gastric acidsecretion, a process of both biological and clinical signiﬁcance, withmicrorobots. Abnormal patterns of acidity often indicate gastrointestinaldiseases, underlying the importance of precise intragastric pH monitoring.Traditional methods using ﬂuorescent probes face challenges due to theirfaint solid-state ﬂuorescence, limited target speciﬁcity, and accuracy. Toovercome these obstacles, pH-responsive ﬂuorescent organic microparticlesdecorated with magnetite (Fe 3 O4 ) nanoparticles are engineered. Thesemicrorobots exhibit a unique ﬂuorescence switching capability at a critical pH,enabling the monitoring of gastric acidity. The magnetic part of thesemicrorobots ensures magnetic maneuverability to enable targeted navigation.The microrobots’ ﬂuorescence switching mechanism is elucidated throughcomprehensive spectroscopy, microscopy, and X-ray diﬀraction analyses,revealing molecular-level structural transformations upon interaction withgastric acid and antacids. These transformations, speciﬁcally protonation anddeprotonation of the microrobots’ ﬂuorescent components, prompt a distinctﬂuorescence response correlating with pH shifts. In vitro and ex vivoexperiments, simulating stomach conditions, conﬁrm the microrobots’eﬃcacy in pH-responsive imaging. The results showcase the promisingdiagnostic potential of microrobots for gastrointestinal tract diseases,marking a signiﬁcant advancement in imaging-based medical diagnostics attargeted locations.
Precision engineering of nanorobots: Toward single atom decoration and defect control for enhanced microplastic capture
(Wiley, 2024) Jančík-Procházková, Anna; Kmentová, Hana; Ju, Xiaohui; Kment, Štěpán; Zbořil, Radek; Pumera, Martin
Nanorobots are being received with a great attention for their move-sense-and-act capabilities that often originate from catalytic decomposition of fuels. In the past decade, single-atom engineering has demonstrated exceptional efficiency in catalysis, energy-related technologies, and medicine. Here, a novel approach involving point defect engineering and the incorporation of platinum (Pt) single atoms and atomic level species onto the surface of titanium dioxide nanotubes (TiO2-NT)-based nanorobots is presented and its impact on the propulsion capabilities of the resulting nanorobots is investigated. The achievement of point defect engineering is realized through the annealing of TiO2-NT in a hydrogen atmosphere yielding to the point-defect decorated nanotube (TiO2-HNT) nanorobots. Subsequently, the atomic level Pt species decorated TiO2 nanotube (TiO2-SA-NT) nanorobots are achieved through a wet-chemical deposition process. Whereas TiO2-SA-NT nanorobots showed the highest negative photogravitaxis when irradiated with ultraviolet (UV) light, TiO2-HNT nanorobots reached the highest velocity calculated in 2D. Both TiO2-HNT and TiO2-SA-NT nanorobots demonstrated a pronounced affinity for microplastics, exhibiting the capability to irreversibly capture them. This pioneering approach utilizing point-defect and atomic level Pt species nanorobotics is anticipated to pave the way for highly efficient solutions in the remediation of nano- and microplastics and related environmental technologies.
Nature-inspired parylene/SiO2 core-shell micro-nano pillars: Effect of topography and surface chemistry
(Elsevier, 2024) Liu, Xiaocheng; Fohlerová, Zdenka; Gablech, Imrich; Pumera, Martin; Neužil, Pavel
We investigated the synergy of surface topography and chemistry in micro/nanostructured pillars inspired by nature, specifically mimicking tokay gecko (Gekko gecko Linnaeus, 1758) feet and sacred lotus (Nelumbo nucifera Gaertn., 1788) leaves. The aim is to understand and replicate their adhesive and self-cleaning properties for diverse applications. Through a detailed fabrication process and chemical modifications, the surfaces exhibit superhydrophobic characteristics. The research precisely examines the fabrication of surfaces with well-defined micropillars using lithography and deep silicon substrate etching. Diverse surface treatments, including silanization and O2 plasma, are applied to tailor the chemical composition of microstructured surfaces. Utilizing a approximate to 5 nm thin SiO2 interface layer, the study reveals superhydrophobic properties post-silanization and an eightfold increase in adhesion force (FA) between the studied surface and reference surfaces. FA measurements using atomic force microscopy reveal an eightfold increase in adhesion on both flat and microstructured surfaces, emphasizing the transformative effects of microstructures on surface morphology. The findings highlight the potential for multifunctional surface designs, elucidating that superhydrophobic properties correlate with structure topography while FA amplitude is predominantly determined by surface termination. Inspired by nature, this research unveils novel possibilities in functional materials and surface engineering, with broad implications across various applications.
Integrated free-standing WS2 3D-printed carbon supercapacitor with solid state electrolyte
(Taylor & Francis, 2024) Mappoli, Shidhin; Ghosh, Kalyan; Pumera, Martin
There is a huge need for energy storage devices due to the depletion of natural gas and the increasing requirement for portable electronic gadgets. Fused deposition modeling (FDM) 3D-printing has drawn tremendous interest for the fabrication of batteries and supercapacitors (SCs) due to its tabletop manufacturing technique, bespoke design, fast prototyping and user-friendly process. However, there are fewer available conductive filaments for FDM printing that are ideal from an energy storage standpoint. 2D transition metal dichalcogenide WS2 has been discovered to be a favourable material for electrochemical energy storage. As a result, in this work, we modified a carbon electrode that was 3D-printed by incorporating WS2 in order to enhance the capacitive performance of the SC electrode. The WS2-coated 3D-printed carbon electrode (WS2/3D-PCE) exhibits 2.8 times higher specific capacitance than the 3D-printed carbon electrode at 50 mV s(-1). A solid-state symmetric supercapacitor (SS-SC) was fabricated with WS2/3D-PCE and polyvinyl alcohol (PVA)/Li2SO4 as gel electrolytes. Such modified 3D-PCE opens up the opportunities to design any custom-shaped electrode with tailored properties and pave a route for future research that will lead to more electrochemical devices for portable electronics.
Formation of Ar2+ ions in cold argon plasmas through the ternary recombination mechanism
(IOP Publishing, 2024) Nongni, F. T.; Kalus, René; Benhenni, Malika; Gadéa, Florent Xavier; Yousfi, Mohammed
A general scheme for calculating ternary recombination rate constants of atomic species based on a hybrid quantum-classical nonadiabatic dynamics approach is presented and applied to the specific case of the ternary recombination of atomic ions of argon in cold argon plasmas. Rate constants are reported for both fine-structure states of the Ar + ion,P- 2(3/2) and(2 )P(1/2), T = 300 K, and for selected values of the reduced electric field. A thorough comparison with the literature data available for T = 300 K and a couple of close temperatures is performed with a favorable agreement achieved. It is shown that the excited Ar + ( P-2 (1/2) ) ions may contribute to the formation of dimer ions, Ar-2(+) , as efficiently as the ground-state ions, Ar + (P-2(3/2) ) , due to fast internal conversion of the electronic energy, which takes place in ternary collision complexes, Ar (+) / Ar / Ar .
On-the-fly monitoring of the capture and removal of nanoplastics with nanorobots
(American Chemical Society, 2024) Velikov, Dean I.; Jančík-Procházková, Anna; Pumera, Martin
Nanoplastics are considered an emerging organic persistent pollutant with possible severe long-term implications for the environment and human health; therefore, their remediation is of paramount importance. However, detecting and determining the concentration of nanoparticles in water is challenging and time-consuming due to their small size. In this work, we present a universal yet simple method for the detection and quantification of nanoplastics to monitor their removal from water using magnetic nanorobots. Nanoplastics were stained with a hydrophobic fluorescent dye to enable the use of photoluminescence techniques for their detection and quantification. Magnetic nanorobotic tools were employed to capture and subsequently remove the nanoplastics from contaminated waters. We demonstrated that nanorobots can capture and remove more than 90% of the nanoplastics from an aqueous solution within 120 min. This work shows that easy-to-use common fluorescent dyes combined with photoluminescence spectroscopy methods can be used as an alternative method for the detection and quantification of nanoplastics in water environments and swarming magnetic nanorobots for efficient capture and removal. These methods hold great potential for future research to improve the quantification and removal of nanoplastics in water, and it will ultimately reduce their harmful impact on the environment and human health.

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