Search results for "Materials Chemistry"
showing 10 items of 6414 documents
LEAVES OFNERIUM OLEANDERL. AS BIOACCUMULATORS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) IN THE AIR OF PALERMO (ITALY): EXTRACTION AND GC-MS ANALYSIS,…
2005
Polycyclic Aromatic Hydrocarbons (PAH) were determined in the leaves of Nerium oleander L. an evergreen plant that occurs widely in both urban and rural areas, to monitor the degree of pollution in the urban area of Palermo (Italy) compared to remote areas. Twenty sites (urban roadside, urban, urban park, suburban and rural) in and around Palermo city were investigated. The purpose of this research was to investigate concentration levels and distribution patterns and relate them to possible sources. Analysis of 19 PAH was performed by gas chromatography/mass spectrometry (GCMS) using selected ion monitoring (SIM). The total amount of PAH ranged from 10 to 166 μg/Kg d.w. Each source gives ri…
An experimental and theoretical study of a heptacoordinated tungsten(VI) complex of a noninnocent phenylenediamine bis(phenolate) ligand
2018
Abstract [W(N2O2)(HN2O2)] (H4N2O2 = N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,2-phenylenediamine) with a noninnocent ligand was formed by reaction of the alkoxide precursor [W(eg)3] (eg = the 1,2-ethanediolate dianion) with two equivalents of ligand. The phenol groups on one of the ligands are completely deprotonated and the ligand coordinates in a tetradentate fashion, whereas the other ligand is tridentate with one phenol having an intact OH group. The molecular structure, magnetic measurements, EPR spectroscopy, and density functional theory calculations indicate that the complex is a stable radical with the odd electron situated on the tridentate amidophenoxide ligand. The formal ox…
Effect of the extensional flow on the properties of oriented nanocomposite films for twist wrapping
2011
In this study, we examined the mechanical behavior of nanocomposite films based on polyethylene (PE) and pristine PE films. The films were prepared by film blowing and were then cold-drawn at low temperature. The experimental results show that cold drawing significantly enhanced the orientation; with increasing draw ratio (DR), the elastic modulus and tensile strength of the PE films strongly increased, particularly in the presence of the organoclay. To obtain polymeric films suitable for twist wrapping, the films must be sufficiently stiff so that no shrinkage or elastic recovery occur during or after twisting. The elongation at break and the yield strain sharply decreased with orientation…
Teaching and Learning of Geometry as a process of Objectification: conditions and obstacles to argumentation and proof. The role of natural language,…
2021
This paper examines some examples (taken from research conducted over the years) that show students’ linguistic attitudes in geometry tasks. The examples are framed within the Theory of Objectification with reference to the notion of sensuous cognition, semiotic means of objectification and levels of generality. We show the struggle students live, at higher levels of generality, in intertwining natural language, specific language and the spontaneous use of geometrical figures, bound to perception and kinaesthetic activity. Within the networking paradigm, we coordinate the Theory of Objectification and Duval’s semio-cognitive approach to frame the interplay between the ideal and the material…
Conformational Dynamics of the Dengue Virus Protease Revealed by Fluorescence Correlation and Single-Molecule FRET Studies.
2021
The dengue virus protease (DENV-PR) represents an attractive target for counteracting DENV infections. It is generally assumed that DENV-PR can exist in an open and a closed conformation and that active site directed ligands stabilize the closed state. While crystal structures of both the open and the closed conformation were successfully resolved, information about the prevalence of these conformations in solution remains elusive. Herein, we address the question of whether there is an equilibrium between different conformations in solution which can be influenced by addition of a competitive inhibitor. To this end, DENV-PR was statistically labeled by two dye molecules constituting a FRET …
Pringle maneuver during open partial nephrectomy for renal tumors
2017
Introduction. Sparing kidney tissue is important because studies show that patients who have their entire kidney removed are more likely to suffer from chronic kidney disease after surgery than patients who received a kidney-sparing partial nephrectomy. The aim of study is to show the effectives of Pringle maneuver for clamping renal pedicle in order to minimize warm ischemia during open partial nephrectomy. Material and method. We retrospectively analyzed 34 patients diagnosed with cT1 renal tumors between 2012 and 2016 and underwent open partial nephrectomy in Sibiu Urology Department. During the surgery we perform clamping of renal pedicle with Satinsky clamp or with the Pringle maneuver…
Waste heat recovery from a marine waste incinerator using a thermoelectric generator
2012
Published version of an article published in the journal: Journal of Electronic Materials. Also available from the publisher at: http://dx.doi.org/10.1007/s11664-012-2009-6 A marine waste incinerator has been evaluated for waste heat harvesting using thermoelectric generators (TEG). The application has been evaluated using mathematical modeling to optimize the heat exchanger and some vital design parameters of the TEG. The calculation shows that it is possible to extract 58 kW el at a price of 6.6 US$/W from an 850-kW th incinerator when optimizing for maximum power. However, minimizing the cost, it is possible to get 25 kW el at a price of 2.5 US$/W. A trade-off between the two targets lea…
The Effect of Electrolytic Solution Composition on the Structure, Corrosion, and Wear Resistance of PEO Coatings on AZ31 Magnesium Alloy
2020
Plasma electrolytic oxidation coatings were prepared in aluminate, phosphate, and silicate-based electrolytic solutions using a soft-sparking regime in a multi-frequency stepped process to compare the structure, corrosion, and wear characteristics of the obtained coatings on AZ31 magnesium alloy. The XRD results indicated that all coatings consist of MgO and MgF2, while specific products such as Mg2SiO4, MgSiO3, Mg2P2O7, and MgAl2O4 were also present in specimens based on the selected solution. Surface morphology of the obtained coatings was strongly affected by the electrolyte composition. Aluminate-containing coating showed volcano-like, nodular particles and craters distributed over the …
Sustainable Supercapacitors Based on Polypyrrole-Doped Activated Biochar from Wood Waste Electrodes
2023
The synthesis of high-performance carbon-based materials from biomass residues for electrodes has been considered a challenge to achieve in supercapacitor-based production. In this work, activated biochar has been prepared as the active electrode material for supercapacitors (SCs), and an effective method has been explored to boost its capacitive performance by employing polypyrrole (PPy) as a biochar dopant. The results for physicochemical characterization data have demonstrated that PPy doping affects the biochar morphology, specific surface area, pore structure, and incorporation of surface functionalities on modified biochar. Biochar-PPy exhibited a surface area of 87 m2 g−1, while pris…
XPS structural data and correlation with Mossbauer spectra for Tin-organic compounds: adducts of RnSnCl4-n with 1,2-bis(diphenylphosphino)ethane
1982
Abstract Core level X-ray photoelectron spectra of 1:1 adducts of SnCl4 and RSnCl3 with DPE {[RnSnCl4−n} · DPE (n = 1, R = Me, Bun, Octn, Phn; n = 2, R = Ph; DPE = 1,2-bis(diphenylphosphino)ethane], have been measured in solid phase. The Sn3d 5 2 binding energies, corrected for the Madelung potential at the metal atom, are well correlated with both partial atomic charge on tin, accounting for relaxation upon ionization, and 119Sn Mossbauer isomer shifts. The results are discussed in terms of these molecular parameters.