84 documents found, page 1 of 9
Characterization of microstructured multiwalled carbon nanotube/polydimethylsil...
Buga, Claudia S.; Tavares, C. J.; Viana, J. C.Technological advancements in the field of flexible and printed electronics are creating a need for large-area sensors that can be embedded over different types of surfaces. Such sensors can be used to monitor physical signals over flexible, curved, or soft devices. Hence, it is herein proposed, a formulation to produce piezoresistive multiwalled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) composites with...
Comparative thermoelectric properties of polypropylene composites melt-processe...
Paleo, Antonio J.; Krause, Beate; Mendes, Ana R.; Tavares, C. J.; Cerqueira, M. F.; Muñoz, Enrique; Pötschke, PetraThe electrical conductivity (σ) and Seebeck coefficient (S) at temperatures from 40 ◦C to 100 ◦C of melt-processed polypropylene (PP) composites filled with 5 wt.% of industrial-grade carbon nanofibers (CNFs) is investigated. Transmission Electron Microscopy (TEM) of the two Pyrograf® III CNFs (PR 19 LHT XT and PR 24 LHT XT), used in the fabrication of the PP/CNF composites (PP/CNF 19 and PP/CNF 24), reveals th...
Thermoelectric and structural properties of transparent Sb-Doped ZnO thin films...
Faria, Helder Filipe; Ribeiro, Joana Margarida Fernandes Silva; Boll, Torben; Tavares, C. J.This study focuses on understanding the influence of low Sb doping on ZnO’s electrical, optical, and thermoelectrical properties, while also studying its structural and morphological parameters. For this, several ZnO films with varying Sb target current densities, in the range of 0–0.27 mA/cm2, were produced by DC magnetron sputtering in a confocal geometry. As a result, thin ZnO:Sb films with an average transp...
Thermoelectric and structural properties of sputtered AZO thin films with varyi...
Isram, Muhammad; Maffei, Riccardo Magrin; Demontis, Valeria; Martini, Leonardo; Forti, Stiven; Coletti, Camilla; Bellani, Vittorio; Mescola, AndreaNanomaterials can be game-changers in the arena of sustainable energy production because they may enable highly efficient thermoelectric energy conversion and harvesting. For this purpose, doped thin film oxides have been proven to be promising systems for achieving high thermoelectric performances. In this work, the design, realization, and experimental investigation of the thermo electric properties exhibited...
Switchable polyacrylic acid polyelectrolyte brushes for surface plasmon resonan...
Al-Bataineh, Qais M.; Telfah, Ahmad D.; Shpacovitch, Victoria; Tavares, C. J.; Hergenröder, RolandImaging wide-field surface plasmon resonance (SPR) microscopy sensors based on poly acrylic acid polyelectrolyte brushes (PAA PEBs) were designed to enhance the sensitivity of nano object detection. The switching behavior of the PAA PEBs against changes in the pH values was investigated by analyzing the chemical, morphological, optical, and electrical properties. At pH ~1, the brushes collapse on the surface wi...
Surface atomic arrangement of aluminum ultra-thin layers grown on Si(111)
Jum’h, Inshad; Abu-Safe, Husam H.; Ware, Morgan E.; Qattan, I. A.; Telfah, Ahmad; Tavares, C. J.Surface atomic arrangement and physical properties of aluminum ultrathin layers on c-Si(111)-7 × 7 and hydrogen-terminated c-Si(111)-1 × 1 surfaces deposited using molecular beam epitaxy were investigated. X-ray photoelectron spectroscopy spectra were collected in two configurations (take-off angle of 0° and 45°) to precisely determine the surface species. Moreover, 3D atomic force microscopy (AFM) images of th...
Dielectric relaxation, XPS and structural studies of polyethylene oxide/iodine ...
Telfah, A.; Al-Akhras, M.-A.; Al-Izzy, K.A.; Ahmad, A. A.; Ababneh, R.; Ahmad, M. J. A.; Tavares, C. J.; Hergenröder, R.Polyethylene oxide (PEO) complexed with molecular iodine (I2) forming PEO/I2 complex composites stand‐free films were investigated using dielectric relaxation, X-ray photoelectron spectroscopy (XPS), UV–Vis spectrophotometry, structural and morphological techniques. Scanning electron microscopy was used to monitor the variation in the surface morphology and the related roughness. 2D Energy-dispersive X-ray spec...
Microencapsulation of essential oils: a review
Sousa, Vânia Isabel; Parente, Joana Filipa; Marques, Juliana Filipa; Forte, Marta Adriana; Tavares, C. J.Essential oils (EOs) are complex mixtures of volatile compounds extracted from different parts of plants by different methods. There is a large diversity of these natural substances with varying properties that lead to their common use in several areas. The agrochemical, pharmaceutical, medical, food, and textile industry, as well as cosmetic and hygiene applications are some of the areas where EOs are widely i...
Joining of zirconia to Ti6Al4V using Ag-Cu sputter-coated Ti brazing filler
Simões, Sónia; Emadinia, Omid; Tavares, C. J.; Guedes, A.The joining of zirconia (ZrO<sub>2</sub>) to Ti6Al4V using Ag-Cu sputter-coated Ti brazing filler foil was investigated. Brazing experiments were performed at 900, 950, and 980 °C for 30 min under vacuum. The microstructural features of the brazed interfaces were evaluated by optical microscopy (OM) and by scanning electron microscopy (SEM). The chemical composition of the brazed interfaces was analyzed by ener...
Use and misuse of the Kubelka-Munk function to obtain the band gap energy from ...
Landi Jr., Salmon; Segundo, Iran Rocha; Freitas, Elisabete; Vasilevskiy, Mikhail; Carneiro, Joaquim A. O.; Tavares, C. J.The determination of the optical band gap energy (Eg ) is important for optimization of the generation of electron/hole pairs in semiconductor materials under illumination. For this purpose, the classical theory proposed by Kubelka and Munk (K-M) has been largely employed for the study of amorphous and polycrystalline materials. In this paper, the authors demonstrate, step by step, how to use the K-M function a...