Jednostka AGH
Wydział Inżynierii Metali i Informatyki Przemysłowej
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- ArtykułOtwarty dostępSmart textiles and the indoor environment of buildings(2022) Priniotakis, Georgios; Stachewicz, Urszula; van Hoof, JoostWydział Inżynierii Metali i Informatyki Przemysłowej
- ArtykułOtwarty dostępPhotoresponsive Electrospun Fiber Meshes with Switchable Wettability for Effective Fog Water Harvesting in Variable Humidity Conditions(2023) Parisi, Gregory; Szewczyk, Piotr K.; Narayan, Shankar; Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejThe global water supply worsens yearly with climate change; therefore, the need for sustainable water resources is growing. One of them is fog water collectors with variable surface wettability, with multifunctional designs for utilization worldwide and to address regions with low humidity levels. Therefore, we created fiber meshes with a photoresponsive switchable surface. This study uses electrospun polyvinylidene fluoride (PVDF) meshes, whose wettability is controlled by adding $TiO_{2}$. The fog water collection performance is studied at high and low humidity levels. With $TiO_{2}-PVDF$, the electrospun mesh can be converted from hydrophobic to hydrophilic under UV irradiation and transformed back to a hydrophobic state with heat treatment. The switchable meshes were found to be more effective at water collection after UV irradiation at lower fog rates of 200 $mL·h^{–1}$. The ability to switch between hydrophobic and hydrophilic properties as needed is highly desired in fog collection applications using electrospun meshes, as it can improve overall efficiency after UV irradiation.
- ArtykułOtwarty dostępSteering triboelectric and mechanical properties of polymer fibers with carbon black(2023) Szewczyk, Piotr K.; Taşlı, Ali Emre; Knapczyk-Korczak, Joanna; Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejThe development of wearable electronics has spurred an increased interest in self-powered systems and triboelectric nanogenerators (TENGs). To enhance the output performance of TENGs, researchers have dedicated significant efforts toward finding effective ways to increase triboelectric and mechanical performance. This study examined how conductive carbon black (CB) affects the mechanical and triboelectric properties of electrospun fibers made of polyurethane (PU), polystyrene (PS), and polycarbonate (PC). The addition of CB affected their mechanical properties, including increased tensile strength and decreased elongation at break. Importantly, triboelectric testing revealed that incorporating CB decreased the triboelectric output of PU and PS by over 90%, while it increased the output of PC by 260%. These findings indicate that CB's effects on triboelectric properties depend on the material and its content, underscoring the importance of selecting CB content carefully for optimal mechanical and triboelectric performance in electrospun fibers and composites. This research validates the development of advanced composite materials for electrostatic discharge protection and energy harvesting applications.
- ArtykułOtwarty dostępMicrostructure study of fractured polar bear hair for toughening, strengthening, stiffening designs via energy dissipation and crack deflection mechanisms in materials(2021) Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejPolar bear hair is known for its superior thermal insulation properties protecting from frigid water and freezing weather conditions. However, this microscopy study on polar bear hair is related to the investigation of the crack stopping mechanisms within its structure following the toughening mechanism principle used by nature. The inhomogeneous structure of polar bear hair consists of fiber bundles, tubules, membranes, porous medulla, and cuticle layers. Precisely, these types of material constructions help impact energy dissipation to protect materials before the failure and save animals via its multifunctionality. The multiscale structures are the key to adopting different physical properties in distinct sizes, from thermal insulation to the toughening, strengthening, and stiffening mechanisms in material designs.
- ArtykułOtwarty dostępOptimizing Piezoelectric Coefficient in PVDF Fibers: Key Strategies for Energy Harvesting and Smart Textiles(2023) Sukumaran, Sunija; Szewczyk, Piotr K.; Knapczyk-Korczak, Joanna; Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejWith the advancement in smart electronic devices and self-powered devices, the demand for piezoelectric polymers found potential research interest. Among these, electrospun polyvinylidene fluoride (PVDF) fibers have gained attention for energy harvesting due to their flexibility and higher piezoelectric coefficient. We compare various methods to enhance PVDF's piezoelectric properties, including different solvents (DMAc, DMF), conductive filler (rGO), and annealing as post-treatment. Our results indicate that PVDF/rGO fibers in DMAc solvent exhibit the highest β phase fraction and crystallinity. Moreover, for the first time, we present the piezoelectric properties of PVDF/rGO electrospun single fiber using high voltage switching spectroscopy piezoelectric force microscopy (HVSS-PFM). The highest piezoelectric coefficient (d33) was measured for PVDF/DMAc-rGO composite fibers. Notably, PVDF/rGO in DMAc solvent significantly improves the piezoelectric coefficient, leading to a remarkable fourfold increase in power density compared to pure PVDF, making it a promising material for energy harvesting applications.
- ArtykułOtwarty dostępNanoparticles distribution and agglomeration analysis in electrospun fiber based composites for desired mechanical performance of poly(3-hydroxybuty-rate-co-3-hydroxyvalerate (PHBV) scaffolds with hydroxyapatite (HA) and titanium dioxide (TiO2) towards medical applications(2022) Karbowniczek, Joanna; Ura, Daniel Paweł; Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejScaffolds designed for tissue engineering must meet multiple criteria, including mechanical performance matching particular tissue properties. One of the strategies to improve electrospun scaffolds strength is the incorporation of ceramic nanoparticles. In this work, the effect of the addition of hydroxyapatite (HA) and titanium dioxide ($TiO_{2}$) nanoparticles on tensile strength, elongation and toughness of poly (3-hydroxybuty-rate-co-3-hydroxyvalerate (PHBV) based fibers was tested. Samples morphology along with chemical composition and particles distribution were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Mechanical properties of PHBV-based electrospun scaffolds were correlated with the nanoparticles' distributions examined via microscopy analysis to understand the failure mechanism of composite fibers. We observed a significant improvement of mechanical properties of composites containing HA nanoparticles compared with solely PHBV fibers. Notably, 3 times higher tensile strength and strain at failure, followed by 16 times improved toughness, was correlated with homogenous distribution of HA nanoparticles with an average area of aggregates reaching 0.11 μm2. At the same time, two times larger $TiO_{2}$ aggregates were irregularly formed along PHBV fibers and caused deterioration of their mechanical properties. We showed the relevant strategy of particle distribution in fibers that are able to tailor mechanical properties by controlling the size and distribution of ceramic fillers in hybrid scaffolds.
- ArtykułOtwarty dostępBridging a Gap in Thermal Conductivity and Heat Transfer in Hybrid Fibers and Yarns via Polyimide and Silicon Nitride Composites(2023) Moradi, Ahmadreza; Szewczyk, Piotr K.; Stachewicz, UrszulaWydział Inżynierii Metali i Informatyki PrzemysłowejThe pressing issues of the energy crisis and rapid electronics development have sparked a growing interest in the production of highly thermally conductive polymer composites. Due to the challenges related to the poor processability of hybrid materials and filler distribution to achieve high thermal conductivity, electrospinning is employed to create composite nanofibers and yarns using polyimide (PI) and thermally conductive silicon nitride (SiN) nanoparticles. The thermal performance of the individual nanofibers is evaluated using scanning thermal microscopy (SThM), providing significant insights into their heat transfer performance. Next, the nanofibers are applied as coatings on resistance wires to assess the thermal conductivity and insulation properties. Notably, the samples containing 35 wt.% of SiN exhibit a 25% increase in surface temperature. These innovative materials hold great promise as exceptional candidates for smart textiles and thermal management applications, addressing the growing demand for effective heat dissipation and regulation.
- Zasób interaktywnyTylko metadanePodstawy baz danych z encyklopedią SQL(2009) Englert, ErykWydział Inżynierii Metali i Informatyki PrzemysłowejStrona internetowa poświęcona jest podstawowym pojęciom związanym z bazami danych. Znajdziesz na niej encyklopedię słów kluczowych języka SQL, służącego do konstruowania zapytań do baz danych. Jeśli nie miałeś do tej pory styczności z SQL możesz skorzystać z kategorii „pierwsze kroki”, w której zebrano podstawowe pojęcia, umożliwiające tworzenie m.in. tabeli w bazie danych, wprowadzanie nowych rekordów, aktualizację ich zawartości lub wyświetlanie. Dodatkowo na stronie znajdziesz informacje nt. modeli baz danych, postulatów Codda, kluczy, więzi, zależności, diagramów ERD, transakcji, czy normalizacji. Możesz również sprawdzić swoją aktualną wiedzę, rozwiązując test. Strona brała udział w konkursie „Notatki w Internecie”.
- Zasób interaktywnyTylko metadaneTechniki programowania aplikacji internetowych w praktyce(2009) Czerner, Dawid; Englert, PawełWydział Inżynierii Metali i Informatyki PrzemysłowejAutorzy strony internetowej opisali najpopularniejsze techniki umożliwiające tworzenie stron internetowych; uwagę skupili przede wszystkim na języku programowania aplikacji internetowych – PHP. Dodatkowo napisali aplikację w JavaScript, która pomoże w nauce programowania zorientowanego obiektowo. W aplikacji tej można w prosty sposób zbudować podstawowy diagram UML, a następnie na jego podstawie wygenerować przykładowy kod PHP.
Strona brała udział w konkursie „Notatki w Internecie”. - Zasób interaktywnyTylko metadaneProjektowanie systemów komputerowych(2009) Frączek, BeataWydział Inżynierii Metali i Informatyki PrzemysłowejStrona internetowa zawiera informacje nt. projektowania systemów informatycznych. Omówione zostały wszystkie rodzaje diagramów UML – możliwe symbole i notacje. Przedstawiono wzorce projektowe oraz język ograniczeń OCL. Zamieszczono również informacje o programowaniu ekstremalnym, zarządzaniu projektami IT oraz kompletną dokumentację projektu Aukcji Internetowej, wykonanego w ramach ćwiczeń przedmiotowych. Strona brała udział w konkursie „Notatki w Internecie”.