Search results for "Note"
showing 10 items of 10709 documents
Renewable polyol obtained by microwave-assisted alcoholysis of epoxidized soybean oil: Preparation, thermal properties and relaxation process
2019
[EN] The soybean oil polyol (SOP) use as feedstock in the polyurethane industry has been recently emphasized due to its excellent resistance to hydrolysis, which is also applicable in coatings and thermal insulation. In this article, the SOP was obtained by a very fast microwave-assisted alcoholysis of epoxidized soybean oil (ESO). The preparation method, thermal properties, and relaxation process were evaluated. High yields as opening and consumption epoxy group and selectivity of 99.8 mol%, 985 mol%, and 71.2 mol% were obtained. Through titrations, nuclear magnetic resonance and gel permeation chromatography were identified parameters as 0.32 mg KOH.g(-1) acid number, 190 mg KOH.g(-1) hyd…
Technical Note: Prediction Models of Airborne Sound Insulation of Multilayer Materials with Viscoelastic Thin Sheets
2008
The growing introduction of new insulation materials in building acoustics has caused an increase of the importance of the prediction tools. Appropriate simulations allow strictly necessary laboratory measurements to be identified. In this way, costs are reduced. The demands of new legislation has resulted in the appearance of various software designed to facilitate prediction. The prediction models are based on different hypotheses: adaptation of impedances, spatial behaviour of spectral components, statistical energy distribution, the Finite Element Method (FEM), etc. Each of these models and methods offer advantages and contain limitations. In this paper, different models for prediction…
Complex power distribution analysis in plates covered with passive constrained layer damping patches
2012
International audience; The vibration of a plate partially covered with a passive constrained layer damping (PCLD) patch is studied from an energetic point of view. The damped plate is excited by an acoustic plane wave. The study is done with a numerical two-dimensional multilayer plate model. Results of the present model are compared to those obtained with three-dimensional finite element models. It is shown that the present model gives accurate results, even for the layer's inner behavior. It is less expansive in terms of computational cost; hence, it can simulate efficiently the structure for higher frequencies. Mathematical formulas for complex mechanical power are presented, and the li…
The 2020 magnetism roadmap
2020
Following the success and relevance of the 2014 and 2017 Magnetism Roadmap articles, this 2020 Magnetism Roadmap edition takes yet another timely look at newly relevant and highly active areas in magnetism research. The overall layout of this article is unchanged, given that it has proved the most appropriate way to convey the most relevant aspects of today's magnetism research in a wide variety of sub-fields to a broad readership. A different group of experts has again been selected for this article, representing both the breadth of new research areas, and the desire to incorporate different voices and viewpoints. The latter is especially relevant for thistype of article, in which one's fi…
Interfacial stabilization by soft Janus nanoparticles
2016
Abstract The stabilization of water/air, water/oil and water/solid interfaces by Janus particles with polystyrene (PS) and poly(methacrylic acid) (PMAA) hemispheres was systematically investigated. The stabilization of these interfaces is of relevance for the formulation of foams, emulsions and dispersions. The Janus particles were prepared from micellar solutions of polystyrene-b-polyisoprene-b-poly(tert-butyl methacrylate) (PS-PI-PtBMA) triblock terpolymers by selective cross-linking of the polyisoprene domain on a multi-gram scale, followed by hydrolysis of the PtBMA block. For the investigation of water/oil-emulsions a series of hydrophobic oils (paraffin oil, xylene, peanut oil, isopro…
Rheological modifiers based on supramolecular block copolymers: From weak associations to interconnected micelles
2019
Abstract The rheological spectra of poly(n-butyl acrylate) in the presence of a series of P(nBA-b-HEMA) rheology modifiers show a two-step relaxation process originating from the PnBA matrix and the self-assemblies. The HEMA segments are further grafted with strong, hydrogen bonding UPy groups, which both magnifies and slows down the relaxation of the assemblies. The extents of associations are enlightened by studying thermal transitions in DSC, morphological developments by SAXS, and description of rheological properties using a tube-based model. It is revealed that a weak association tendency, due to long hydrophobic blocks, leads to the formation of double-linear or star assemblies, whil…
Aequorin-expressing yeast emits light under electric control
2011
In this study, we show the use of direct external electrical stimulation of a jellyfish luminescent calcium-activated protein, aequorin, expressed in a transgenic yeast strain. Yeast cultures were electrically stimulated through two electrodes coupled to a standard power generator. Even low (1.5. V) electric pulses triggered a rapid light peak and serial light pulses were obtained after electric pulses were applied periodically, suggesting that the system is re-enacted after a short refraction time. These results open up a new scenario, in the very interphase between synthetic biology and cybernetics, in which complex cellular behavior might be subjected to electrical control.
Pefloxacine mesilate- and ofloxacin-loaded polyethylcyanoacrylate nanoparticles: characterization of the colloidal drug carrier formulation.
1995
The entrapment of fluoroquinolones, perfloxacine mesilate (PFX) and ofloxacin (OFX), in polyalkylcyanoacrylate (PECA) nanoparticles could offer some advantages for their biological application; for examples, increasing their bioavailability, controlling the drug time-release in blood, and reducing the formation of bacterial resistance. To load these two drugs in PECA polymeric bulk, the incorporation or adsorption method was performed. These two methods were capable of influencing nanoparticle size, molecular weight, release profile, and drug–polymer association. The incorporation method, particularly for the OFX system, achieved PECA nanoparticle suspensions with a mean size value three ti…
Pressure-Stabilized Solvates of Xylazine Hydrochloride
2016
High pressure strongly favors the highest-density polymorph Z of active pharmaceutical ingredient 2-(2,6-xylidino)-5,6-dihydro-4H-1,3-thiazine hydrochloride (xylazine hydrochloride, XylHCl) up to about 0.1 GPa only, but still higher pressure destabilizes this structure. Above 0.1 GPa, XylHCl preferentially crystallizes as solvates with CH2Cl2, CHCl3, or (CH3)2CHOH depending on the solvent used. However, when XylHCl·H2O is dissolved in any of these solvents, the high-pressure crystallizations yield the hydrate XylHCl·H2O only. The single crystals of the CH2Cl2, CHCl3, and (CH3)2CHOH solvates could be grown in situ in a diamond anvil cell, which allowed their structure determination from the …
Thermodynamic Characterization Of Two Layers Of CO2 On A Graphite Surface
2014
We find by examination of density profiles that carbon dioxide adsorbs on graphite in two distinct layers. We report the activity coefficient, entropy and enthalpy for CO2 in each layer using a convenient computational method, the Small System Method, thereby extending this method to surfaces. This opens up the possibility to study thermodynamic properties for a wide range of surface phenomena. © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).