1. Antimicrobial activity of amino-modified cellulose nanofibrils decorated with silver nanoparticlesVesna Lazić, Jovan Nedeljković, Vanja Kokol, 2024, original scientific article Abstract: Silver nanoparticles (Ag NPs) conjugated with amino-functionalized cellulose nanofibrils (NH2−CNFs) were in situ-prepared by reducing silver ions with free amino groups from NH2−CNFs. The spectroscopy and transmission electron microscopy measurements confirmed the presence of non-agglomerated nanometer-in-size Ag NPs within micrometer-large NH2−CNFs of high (20 wt.-%) content. Although the consumption of amino groups during the formation of Ag NPs lowers the ζ-potential and surface charge of prepared inorganic–organic hybrids (from +31.3 to +19.9 mV and from 2.4 to 1.0 mmol/g at pH 7, respectively), their values are sufficiently positive to ensure electrostatic interaction with negatively charged cell walls of pathogens in acidic and slightly (up to pH ~8.5) alkaline solutions. The antimicrobial activity of hybrid microparticles against various pathogens (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans) is comparable with pristine NH2−CNFs. However, a long-timescale use of hybrids ensures the slow and controlled release of Ag+ ions to surrounding media (less than 1.0 wt.-% for one month).
Keywords: amino-modified cellulose nanofibrils, silver nanoparticles, hybrid microparticles, zeta-potential, antimicrobial activity
Published in DKUM: 09.12.2024; Views: 0; Downloads: 0
 Full text (3,84 MB)
This document has many files! More... |
2. Development of novel hybrid TPMS cellular lattices and their mechanical characterisationNejc Novak, Oraib Al-Ketan, Matej Borovinšek, Lovre Krstulović-Opara, Reza Rowshan, Matej Vesenjak, Zoran Ren, 2021, original scientific article Abstract: Uniform lattices composed of one type of lattice structure repeated periodically have been extensively investigated in literature for their mechanical and physical properties. Their promising properties, which include a desirable combination of high strength, stiffness and toughness, suggest that hybrid structures made of two or more lattice types can exhibit even more advantageous and desired properties. In this work, the mechanical properties of hybrid cellular structures designed using implicit functions are investigated both experimentally and numerically. Two proposed samples are investigated comprised of a Gyroid and a Diamond unit cells hybridised linearly and radially. First, a finite element computational model was utilised in LS-DYNA to capture the mechanical properties of the additively manufactured constituent lattices (i.e., Gyroid and Diamond) made of stainless steel 316L and tested under dynamic and quasi-static loading conditions. The model was validated for three different relative densities. Then, the validated computational model was then tested to predict the mechanical behaviour of the proposed hybrid lattices. Finally, the proposed hybrid lattices were fabricated and mechanically tested to obtain their mechanical properties. A good agreement between experimental and computational results was achieved. The validated computational models will be used to evaluate other designs of TPMS lattices and their crashworthiness performance for protective equipment applications.
Keywords: cellular materials, triply periodical minimal surface, hybrid lattices, experimental testing, computational modelling, multi-morphology
Published in DKUM: 27.11.2024; Views: 3; Downloads: 0
Full text (3,99 MB)
This document has many files! More... |
3. Ergonomic evaluation of human–robot collaborative order picking : a combined laboratory and simulation studyMinqi Zhang, Jakob Marolt, Primož Bencak, Eric Grosse, Tone Lerher, 2024, published scientific conference contribution Abstract: Thanks to rapid technological developments in robotics, various automation technologies are being applied in warehouses today. Order picking, as a key process in warehouse operations, has drawn attention in academia and practice for decades. In addition to many studies dedicated to manual and fully automated order picking, efforts have also been made to study semi-automated warehouses in which humans and robots collaborate. However, these studies mostly focused on system efficiency and ignored ergonomic aspects. Order picking was confirmed as a labor-intensive process in an environment in which workers are at a high risk of developing health problems. Therefore, this study addresses the investigation of physical human working conditions in both manual and robot-assisted order picking systems via real-life laboratory experiments and simulation modeling. We used a motion capture system to assess human working postures when working with and without robot assistance. In addition, we estimated the daily workload by applying the energy expenditure concept. Using simulation experiments, we were able to extend the results to various practical scenarios with different design variables, for example warehouse layouts, order sizes, and human-robot team configuration. Our preliminary results reveal that human-robot collaboration can reduce human workload. Posture evaluation also shows a slight improvement.
Keywords: order picking, autonomous mobile robot, human factors, ergonomics, assisted order picking, hybrid order picking, simulation, performance evaluation
Published in DKUM: 21.11.2024; Views: 0; Downloads: 2
Full text (713,52 KB)
This document has many files! More... |
4. Hybrid visualization-based framework for depressive state detection and characterization of atypical patientsLeon Kopitar, Peter Kokol, Gregor Štiglic, 2023, original scientific article Keywords: hybrid visualization, interpretation, explainable, shapley, feature importance, depression
Published in DKUM: 12.06.2024; Views: 101; Downloads: 9
Full text (1,83 MB)
This document has many files! More... |
5. Mechanical performance and failure behavior of hybrid screw-bonded joints of aluminum sheets and cross-laminated birch veneer platesJosef Domitner, Zahra Silvayeh, Jožef Predan, Eva Graf, Thomas Krenke, Nenad Gubeljak, 2023, original scientific article Keywords: lightweight design, multi-material car body, aluminum alloy, wood veneer, aluminum-wood joints, hybrid joining, static strength, fatigue performance
Published in DKUM: 28.03.2024; Views: 223; Downloads: 13
Full text (5,21 MB)
This document has many files! More... |
6. Hybrid polylactic-acid–pectin aerogels : synthesis, structural properties, and drug releaseGabrijela Horvat, Klara Žvab, Željko Knez, Zoran Novak, 2023, original scientific article Abstract: Wound-dressing materials often include other materials stimulating wound healing. This research describes the first formulation of biodegradable hybrid aerogels composed of polylactic acid and pectin. The prepared hybrid material showed a highly porous structure with a surface area of 166 +/- 22.6 m(2)center dot g(-1). The addition of polylactic acid may have decreased the surface area of the pure pectin aerogel, but it improved the stability of the material in simulated body fluid (SBF). The pure pectin aerogel showed a high swelling and degradation ratio after 3 h. The addition of the polylactic acid prolonged its stability in the simulated body fluid from 24 h to more than one week, depending on the amount of polylactic acid. Biodegradable aerogels were loaded with indomethacin and diclofenac sodium as model drugs. The entrapment efficiencies were 63.4% and 62.6% for indomethacin and diclofenac sodium, respectively. Dissolution of both drugs was prolonged up to 2 days. Finally, sodium percarbonate and calcium peroxide were incorporated into the bioaerogels as chemical oxygen sources, to evaluate oxygen generation for potential wound healing applications.
Keywords: hybrid aerogels, bioaerogel, pectin, polylactic acid, wound healing
Published in DKUM: 20.02.2024; Views: 357; Downloads: 24
Full text (2,62 MB)
This document has many files! More... |
7. Reduction of Neural Machine Translation Failures by Incorporating Statistical Machine TranslationJani Dugonik, Mirjam Sepesy Maučec, Domen Verber, Janez Brest, 2023, original scientific article Abstract: This paper proposes a hybrid machine translation (HMT) system that improves the quality of neural machine translation (NMT) by incorporating statistical machine translation (SMT). Therefore, two NMT systems and two SMT systems were built for the Slovenian-English language pair, each for translation in one direction. We used a multilingual language model to embed the source sentence and translations into the same vector space. From each vector, we extracted features based on the distances and similarities calculated between the source sentence and the NMT translation, and between the source sentence and the SMT translation. To select the best possible translation, we used several well-known classifiers to predict which translation system generated a better translation of the source sentence. The proposed method of combining SMT and NMT in the hybrid system is novel. Our framework is language-independent and can be applied to other languages supported by the multilingual language model. Our experiment involved empirical applications. We compared the performance of the classifiers, and the results demonstrate that our proposed HMT system achieved notable improvements in the BLEU score, with an increase of 1.5 points and 10.9 points for both translation directions, respectively.
Keywords: neural machine translation, statistical machine translation, sentence embedding, similarity, classification, hybrid machine translation
Published in DKUM: 20.02.2024; Views: 322; Downloads: 28
Full text (400,40 KB)
This document has many files! More... |
8. Data sharing concepts : a viable system model diagnosisIgor Perko, 2023, original scientific article Abstract: Purpose Artificial intelligence (AI) reasoning is fuelled by high-quality, detailed behavioural data. These can usually be obtained by the biometrical sensors embedded in smart devices. The currently used data collecting approach, where data ownership and property rights are taken by the data scientists, designers of a device or a related application, delivers multiple ethical, sociological and governance concerns. In this paper, the author is opening a systemic examination of a data sharing concept in which data producers execute their data property rights. Design/methodology/approach Since data sharing concept delivers a substantially different alternative, it needs to be thoroughly examined from multiple perspectives, among them: the ethical, social and feasibility. At this stage, theoretical examination modes in the form of literature analysis and mental model development are being performed. Findings Data sharing concepts, framework, mechanisms and swift viability are examined. The author determined that data sharing could lead to virtuous data science by augmenting data producers' capacity to govern their data and regulators' capacity to interact in the process. Truly interdisciplinary research is proposed to follow up on this research. Research limitations/implications Since the research proposal is theoretical, the proposal may not provide direct applicative value but is largely focussed on fuelling the research directions. Practical implications For the researchers, data sharing concepts will provide an alternative approach and help resolve multiple ethical considerations related to the internet of things (IoT) data collecting approach. For the practitioners in data science, it will provide numerous new challenges, such as distributed data storing, distributed data analysis and intelligent data sharing protocols. Social implications Data sharing may post significant implications in research and development. Since ethical, legislative moral and trust-related issues are managed in the negotiation process, data can be shared freely, which in a practical sense expands the data pool for virtuous research in social sciences. Originality/value The paper opens new research directions of data sharing concepts and space for a new field of research.
Keywords: hybrid reality, data sharing, systems thinking, cybernetics, artificial intelligence
Published in DKUM: 14.02.2024; Views: 367; Downloads: 17
Full text (663,49 KB)
This document has many files! More... |
9. Innovative structural systems for timber buildings : A comprehensive review of contemporary solutionsMiroslav Premrov, Vesna Žegarac Leskovar, 2023, review article Abstract: The remarkable development of timber construction technologies in recent decades has led to an increase in the number of timber buildings worldwide, including multi-storey buildings. The design of timber buildings, especially those of greater height, is relatively demanding and, even in the context of architectural expression, has certain constraints due to the specific structural and physical properties of this material. Thus, it is important for designers to have an overview of existing timber structural systems and their specificities to be able to make the right design decisions during the design process. Unfortunately, there is a lack of scientific literature that systematically addresses the essential features of contemporary timber structural systems. Within the aims of this paper to provide the systematic review of contemporary structural systems, both the scientific and professional literature are comprehensively reviewed. This paper presents a systematic classification and description of the following structural systems of timber buildings: all-timber and hybrid timber structural systems with an additional description of constituent structural elements, while examples of completed multi-storey timber buildings are also given for each structural system. The findings provide a broader view of the knowledge of contemporary solutions of timber structural systems and their application, thus representing a novelty in the field of timber construction review.
Keywords: timber structural systems, hybrid timber structural system, timber-concrete composite, timber-steel composite, timber-timber composite, timber structural elements, timber buildings, multi-storey timber buildings
Published in DKUM: 09.02.2024; Views: 261; Downloads: 42
Full text (1,31 MB)
This document has many files! More... |
10. Influence of Numerical Mesh Type on Airfoil Aerodynamic CharacteristicsMarko Pezdevšek, Matej Fike, Andrej Predin, Gorazd Hren, 2019, published scientific conference contribution Abstract: In this paper, we will examine how different mesh types affect the aerodynamic characteristic of an airfoil. The airfoil used for this paper was the NREL S809. Three different mesh types were created, a blocked structured mesh, an unstructured mesh and a hybrid mesh containing a blocked structured mesh near the surface of the airfoil and an unstructured mesh on the outside perimeter. Steady state simulations were performed for angles of attack between 0°and 22°. Lift and drag coefficient for all created meshes were compared to experimental results from literature. From angles of attack between 2° and 8° all three meshes predict similar lift and drag coefficients. We encountered problems with convergence for the unstructured mesh at angles of attack higher than 8°. Structured and hybrid mesh had similar lift and drag coefficients across all angles of attack.
Keywords: computational fluid dynamics, NREL S809, structured mesh, unstructured mesh, hybrid mesh
Published in DKUM: 04.12.2023; Views: 361; Downloads: 28
Full text (18,06 MB)
This document has many files! More... |
