Search results for " Materials Science"
showing 10 items of 7414 documents
Conduction properties of thin films from a water soluble carbon nanotube/hemicellulose complex.
2018
We have examined the conductive properties of carbon nanotube based thin films, which were prepared via dispersion in water by non-covalent functionalization of the nanotubes with xylan, a type of hemicellulose. Measurements of low temperature conductivity, Kelvin probe force microscopy, and high frequency (THz) conductivity elucidated the intra-tube and inter-tube charge transport processes in this material. The measurements show excellent conductive properties of the as prepared thin films, with bulk conductivity up to 2000 S cm−1. The transport results demonstrate that the hemicellulose does not seriously interfere with the inter-tube conductance. peerReviewed
Ecofriendly Biopolymer-Based Nanocomposite Films with Improved Photo-Oxidative Resistance
2022
The interest towards high performance biopolymer-based materials increases continuously and, to guarantee appropriately industrial applications, the photo-oxidative resistance and stability of these materials must be adequately addressed. In this study, innovative biopolymer-based nanocomposites, i.e., Polyamide 11 (PA11), containing ad-hoc modified Layered Double Hydroxides (LDH), were successfully formulated and characterized. Particularly, LDH were considered carriers for hindered amine light stabilizing molecules, so two different hindered amine moieties (HALS1 and HALS2) were anchored on LDH layered internal structures and/or outer surfaces. The presence of HALS1 and HALS2 in LDH were …
Of Friends and Foes in Organizations: A Theoretical Perspective Upon Performance at Work
2014
Abstract The present paper highlights, from a theoretical perspective, the main challenges which aim work performance, inside meta- analytical research studies in organizations, focusing, especially, on factors and organizational concepts, directly related to performance and their relations within. Results show that, in most cases, human resources oriented management resides in an increase of performance at work. In this manner, team effectiveness, group size and proactive behavior determine and influence the levels of work performance, from a positive perspective, whilst turnover is widely associated with a negative view.
A chitosan/silica hybrid 3D scaffold for simultaneous entrapment of two different hydrophilic substances
2022
We report the preparation of a hybrid chitosan/silica three-dimensional (3D) scaffold loaded simultaneously with two model hydrophilic substances, ibuprofen sodium salt and erioglaucine disodium salt. The first substance is entrapped in situ during the preparation of chitosan submillimetric beads by ionotropic gelation with sodium triphosphate, while the latter is post-loaded during the scaffold formation. Controlled release experiments carried out under neutral conditions demonstrate that the presence of nanostructured silica within the polymer matrix retards the release of both hydrophilic substances and increases the structure stability of the scaffold. Release profiles can be fitted to …
Cationic and Anionic Impact on the Electronic Structure of Liquid Water
2017
Hydration shells around ions are crucial for many fundamental biological and chemical processes. Their local physicochemical properties are quite different from those of bulk water and hard to probe experimentally. We address this problem by combining soft X-ray spectroscopy using a liquid jet and molecular dynamics (MD) simulations together with ab initio electronic structure calculations to elucidate the water–ion interaction in a MgCl2 solution at the molecular level. Our results reveal that salt ions mainly affect the electronic properties of water molecules in close vicinity and that the oxygen K-edge X-ray emission spectrum of water molecules in the first solvation shell differs signi…
Crystal structure and Hirshfeld surface analysis of (2E)-3-(3-bromo-4-fluorophenyl)-1-(3,4-dimethoxyphenyl)prop-2-en-1-one
2018
The title compound is constructed from two aromatic rings (3-bromo-4-fluorophenyl and 3,4-dimethoxyphenyl), which are linked by a C=C—C(=O)—C enone bridge and form a dihedral angle of 17.91 (17)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds enclosing rings of (14) graph-set motif to form layers parallel to (10).
Structural and Electrochemical Analysis of CIGS: Cr Crystalline Nanopowders and Thin Films Deposited onto ITO Substrates
2021
A new approach for the synthesis of nanopowders and thin films of CuInGaSe2 (CIGS) chalcopyrite material doped with different amounts of Cr is presented. The chalcopyrite material CuInxGa1 − xSe2 was doped using Cr to form a new doped chalcopyrite with the structure CuInxCryGa1 − x − ySe2, where x = 0.4 and y = 0.0, 0.1, 0.2, or 0.3. The electrical properties of CuInx CryGa1 − x − ySe2 are highly dependent on the Cr content and results show these materials as promising dopants for the fabrication thin film solar cells. The CIGS nano-precursor powder was initially synthesized via an autoclave method, and then converted into thin films over transparent substrates. Both crystalline precursor p…
Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria
2018
A simple and straightforward synthetic approach for carbon nanodots (C-dots) is proposed. The strategy is based on a one-step hydrothermal chemical reduction with thiourea and urea, leading to high quantum yield C-dots. The obtained C-dots are well-dispersed with a uniform size and a graphite-like structure. A synergistic reduction mechanism was investigated using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The findings show that using both thiourea and urea during the one-pot synthesis enhances the luminescence of the generated C-dots. Moreover, the prepared C-dots have a high distribution of functional groups on their surface. In this work, C-dots proved …
CoS2/TiO2 Nanocomposites for Hydrogen Production under UV Irradiation
2019
Transition metal chalcogenides have intensively focused on photocatalytic hydrogen production for a decade due to their stronger edge and the quantum confinement effect. This work mainly focuses on synthesis and hydrogen production efficiencies of cobalt disulfide (CoS2)-embedded TiO2 nanocomposites. Materials are synthesized by using a hydrothermal approach and the hydrogen production efficiencies of pristine CoS2, TiO2 nanoparticles and CoS2/TiO2 nanocomposites are compared under UV irradiation. A higher amount of hydrogen production (2.55 mmol g&minus
Bone-Healing Pattern on the Surface of Titanium Implants at Cortical and Marrow Compartments in Two Topographic Sites: an Experimental Study in Rabbi…
2018
This study evaluates the bone-healing patterns on the surface of titanium implants at the cortical and marrow compartments of bicortically-installed implants in the diaphysis and metaphysis of rabbit tibiae. In 27 New Zealand rabbits, two implants, one for each macro-design and with equal resorbable blasted media (RBM) implant surfaces, were randomly implanted in the diaphysis or metaphysis of each tibia. The flaps were sutured to allow submerged healing. The animals were sacrificed after two, four, or eight weeks, with nine weeks used for the period of healing. Ground sections were prepared and analyzed. No statistically significant differences were found between the two groups for newly f…