Search results for "spray"
showing 10 items of 503 documents
Elaboration et caractérisation mécanique et physico-chimique des revêtements déposés sur des substrats en laiton par les techniques de projection the…
2019
Brass alloys are used in many applications, especially in the sanitary industrial application. In this field, the brass is coated with an electroplated chromium layer. However, the electroplating technique is achieved by means of solutions in which the chromium is in the six oxidation state. At this degree of oxidation, chromium is toxic and has the reputation of being carcinogenic. In this context, the main objective of this work is to develop functional coatings on brass substrates using new techniques namely thermal and pneumatic spraying techniques. The mechanical and physical-chemical properties are studied in order to evaluate the performances of these coatings and the potency of thei…
Manufacturing and characterization of Al matrix composites with nano reinforcements via cold spraying
2019
This study aims at developing new routes for manufacturing Al matrix composites (AMCs) strengthened with nano reinforcements by solid-state cold spraying (CS) process. Three different AMCs including CNTs/Al, TiB2/AlSi10Mg and TiB2/7075Al were successfully fabricated by CS of the composite powders prepared using different approaches. The microstructure evolution of as-sprayed composite samples was investigated by means of different characterization methods like X-ray diffraction (XRD), scanning (SEM) and transmission electron microscopy (TEM) and electron backscatter diffraction (SEM/EBSD). The adhesion strength, tribological behaviour, corrosion properties as well as the mechanical performa…
Spot spraying in oilseeds and protein crops
2019
International audience; Currently, spraying chemical products in agriculture became the main means of weed controlbecause this cultural practice is very fast, inexpensive and very effective. However, awarenessof their negative impacts (environment, human health) requires thinking about new technicaland agronomic solutions. New technologies are promising techniques for a site-specific weedmanagement through the development of localized spraying.Some sprayers (often small width) located on the row may be able to answer thoseexpectations but they are most often expensive. In this context, the objective of the project“PLEVOP” (development of spot sprayer in oilseed and protein crops), proposed …
Effects of the net charge on abundance and stability of supramolecular surfactant aggregates in gas phase
2011
Self-assembling of amphiphilic molecules under electrospray ionization (ESI) conditions is characterized by quite unexpected phenomenology. The noticeable differences with respect to the condensed phase are attributable to the absence of the surfactant-solvent interactions, the presence of net charge in the aggregates, and the strong deviation from equilibrium conditions. Aiming to investigate the effects of the net charge on abundance and stability of supramolecular surfactant aggregates, positively and negatively charged aggregates of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and sodium methane sulfonate (MetS), butane sulfonate (ButS) and octane sulfonate (OctS) have been studied by E…
Molecular dynamics of electrosprayed water nanodroplets containing sodium bis(2-ethylhexyl)sulfosuccinate
2013
The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) subject to electrospray ionization (ESI) has been investigated by molecular dynamics (MD) simulations at three temperatures (350, 500 and 800 K). We consider several types of water nanodroplets containing AOTNa molecules and composed of a fixed number of water molecules (1000), N(AOT)(0) AOT(-) anions (N(AOT)(0) = 0, 5, 10) and N(Na)(0) sodium ions (N(Na)(0) = 0, 5, 10, 15, 20): in a short time scale (less than 1 ns), the AOTNa molecules, initially forming direct micelles in the interior of the water nanodroplets, are observed in all cases to diffuse nearby the nanodroplet surface, so that the hydrophilic …
Biopolymer-Based Hybrid Hydrogels for Biomedical Applications: From Macroscopic to Nanosized Systems
2021
Les partícules portadores basades en biopolímers són biocompatibles i ofereixen la capacitat d’incorporar agents actius hidròfils i hidròfobs. La incorporació d’un fàrmac en una matriu polimèrica pot millorar-ne la protecció contra la degradació en mitjans fisiològics severs. A més, pot controlar-ne l’alliberament al lloc d’acció específic, amb una biodisponibilitat terapèutica augmentada i efectes secundaris o toxicitat minimitzats. Aquesta tesi presenta la preparació de diferents sistemes híbrids de polisacàrids per a encapsular substàncies hidròfiles, que posteriorment són alliberades. Es preparen portadors que varien de mida macroscòpica a nanomètrica mitjançant diferents mètodes: gelif…
A multi-model assessment of the efficacy of sea spray geoengineering
2012
Abstract. Artificially increasing the albedo of marine clouds by the mechanical emission of sea spray aerosol has been proposed as a geoengineering technique to slow the warming caused by anthropogenic greenhouse gases. A previous global model study found that only modest increases and sometimes even decreases in cloud drop number (CDN) concentrations would result from plausible emission scenarios. Here we extend that work to examine the conditions under which decreases in CDN can occur, and use three independent global models to quantify maximum achievable CDN changes. We find that decreases in CDN can occur when at least three of the following conditions are met: the injected particle num…
Sedation in allergic rhinitis is caused by the condition and not by antihistamine treatment
1996
Sedation is regarded as a common side-effect of most H1-antihistamines. This view must be accepted, yet can hardly be assessed under treatment of allergic disorders. Since central sedative potency is hard to evaluate, different methods of measurement have been introduced in the four phases of clinical investigation. While tests of high complexity in early trials can detect true central effects, they seem to have the disadvantage of not taking into consideration the important interactions of drugs with the disorder. Therefore, we used a visual analog scale (VAS) as an instrument to demonstrate sedative effects in five clinical studies carried out between 1989 and 1994 with a total number of …
Binding Profiles of Self-Assembled Supramolecular Cages from ESI-MS Based Methodology
2018
Confined molecular environments have peculiar characteristics that make their properties unique in the field of biological and chemical sciences. In recent years, advances in supramolecular capsule and cage synthesis have presented the possibility to interpret the principles behind their self‐assembly and functions, which has led to new molecular systems that display outstanding properties in molecular recognition and catalysis. Herein, we report a rapid method based on ESI‐MS to determine the binding profiles for linear saturated dicarboxylic acids in a series of different cages. The cages were obtained by self‐assembly of modified tris(pyridylmethyl)amine (TPMA) complexes and diamines cho…
Thermodynamic studies of iron(III) complex of some new dihydroxamic acids model of rhodotorulic acid
2018
Abstract The objective of this research is to elucidate the coordination chemistry and the structure of complexes formed with siderochelates organic ligands and the physico-chemical studies of iron(III) complexation. Three dihydroxamic acids synthesized ((LCyEt)2−, (LCyPr)2− and (LO)2−) mimicking a fungal siderophore, rhodotorulic acid. They were evaluated with iron(III) chelation by potentiometric and spectrophotometric titrations in 0.1 M KNO3. These measurements revealed the formation of dileptic and trileptic complexes in excess ligand conditions. The chemical model includes five species of [Fem(L)lHh](3m−2l+h)+ with general formula: [Fe(L)]+, [Fe(L)(OH)], [Fe(L)(OH)2]−, [Fe(L)2H] and […