Search results for "POWDER"

showing 10 items of 437 documents

MoSi2 laser cladding—a comparison between two experimental procedures: Mo–Si online combination and direct use of MoSi2

2001

International audience; There are very strong interests in developing low density advanced material systems for service at temperatures up to 1300°C. These materials should mainly have moderate fracture toughness at low and intermediate temperatures and should exhibit oxidation resistant behaviour. The intermetallic compound, MoSi2 has been considered to be an attractive candidate due to its melting point (2030°C) and excellent oxidation resistance at high temperatures. In this paper, we compare the results obtained with two different techniques for laser cladding, one using an online combination between Mo and Si powders, the second using direct injection of the MoSi2 powder.

TechnologyMaterials scienceOxidation resistantIntermetallic[ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Laser02 engineering and technology01 natural scienceslaw.inventionFracture toughnesslaw0103 physical sciencesLow densityElectrical and Electronic EngineeringComposite materialOxidation resistance010302 applied physicsMaterial system021001 nanoscience & nanotechnologyLaserAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsMelting point[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Powders0210 nano-technology
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Moringa oleifera Leaf Powder as Functional Additive in Cookies to Protect SH-SY5Y Cells

2021

The aim of this work is the evaluation of the addition of Moringa leaf powder (MLP) in cookies in terms of antioxidant properties, dough processability and sensorial properties of the cookies. The total content of biophenols and flavonoids in MLP was detected and the identification of the bioactive molecules was performed by HPLC-ESI-TOF-MS measurements, before and after oven treatment at 180 ◦C for 20 min. After a preliminary evaluation of the MLP water soluble fraction (MLPsf) cytotoxicity, its protective effect against an oxidative injury induced in the SH-SY5Y cells was assessed. Data evidence that the bioactive molecules present in MLPsf are effective in preventing ROS production and i…

TechnologySH-SY5YAntioxidantQH301-705.5QC1-999Bioactive moleculesmedicine.medical_treatmentCytotoxicitymedicine.disease_causeMORINGA OLEIFERA LEAFantioxidant effectsMoringachemistry.chemical_compoundHPLC-ESI-TOF-MS identificationsAntioxidant effects Cytotoxicity HPLC-ESI-TOF-MS identifications Moringa leaf powder Rheologymedicinemoringa leaf powderGeneral Materials ScienceOxidative injuryFood scienceBiology (General)QD1-999InstrumentationFluid Flow and Transfer ProcessesTPhysicsProcess Chemistry and TechnologyGeneral Engineeringfood and beveragesmoringa leaf powder; HPLC-ESI-TOF-MS identifications; cytotoxicity; antioxidant effects; rheology; SEMEngineering (General). Civil engineering (General)Moringa leaf powderComputer Science ApplicationsChemistrychemistryAntioxidant effectsSEMcytotoxicityrheologySettore CHIM/07 - Fondamenti Chimici Delle TecnologieTA1-2040KaempferolRheologyOxidative stress
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Thermal and X-ray powder diffraction studies of aliphatic polyester dendrimers

2004

The syntheses and thermal and X-ray powder diffraction analyses of three sets of aliphatic polyester dendrimers based on 2,2-bis(hydroxymethyl)propionic acid as a repeating unit and 2,2-dimethyl-1,3-propanediol, 1,5-pentanediol, and 1,1,1-tris(hydroxymethyl)ethane as core molecules are reported. These dendritic polyesters were prepared in high yields with the divergent method. The thermal properties of these biodendrimers were evaluated with thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition of the compounds occurred around 250 °C for the hydroxyl-ended dendrimers and around 150 °C for the acetonide-protected dendrimers. In addition, the crystallinit…

Thermogravimetric analysisDendrimersPolymers and PlasticsChemistryThermogravimetric analysis (TGA)2-bis(hydroxymethyl)propionic acid (bis-MPA)Organic ChemistryThermal decomposition2Differential scanning calorimetry (DSC)PolyesterCrystallinitychemistry.chemical_compoundDifferential scanning calorimetryDendrimerPolymer chemistryMaterials Chemistry22-bis(hydroxymethyl)propionic acid (bis-MPA)Physical chemistryAliphatic polyestersHydroxymethylPowder diffraction
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Elucidating Gating Effects for Hydrogen Sorption in MFU-4-Type Triazolate-Based Metal-Organic Frameworks Featuring Different Pore Sizes

2011

A highly porous member of isoreticular MFU-4-type frameworks, [Zn(5)Cl(4)(BTDD)(3)] (MFU-4l(arge)) (H(2)-BTDD=bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin), has been synthesized using ZnCl(2) and H(2)-BTDD in N,N-dimethylformamide as a solvent. MFU-4l represents the first example of MFU-4-type frameworks featuring large pore apertures of 9.1 Å. Here, MFU-4l serves as a reference compound to evaluate the origin of unique and specific gas-sorption properties of MFU-4, reported previously. The latter framework features narrow-sized pores of 2.5 Å that allow passage of sufficiently small molecules only (such as hydrogen or water), whereas molecules with larger kinetic diameters (e.…

Thermogravimetric analysisHydrogenChemistryThermal desorption spectroscopythermal desorption spectroscopyOrganic ChemistryInorganic chemistrytriazolateschemistry.chemical_elementGeneral ChemistryCrystal structureCatalysisadsorption; hydrogen; metal-organic frameworks; thermal desorption spectroscopy; triazolatesAdsorptionadsorptionhydrogenDesorptionPhysical chemistryddc:530Metal-organic frameworkmetal-organic frameworksPowder diffractionChemistry - A European Journal
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Nanocomposites of bacterial cellulose/hydroxyapatite for biomedical applications.

2008

In the present work, a nanocomposite material formed by bacterial cellulose (BC) networks and calcium-deficient hydroxyapatite (HAp) powders was synthesized and characterized. The HAp nanoparticles were previously prepared by a wet chemical precipitation method, starting from aqueous solutions of calcium nitrate and di-ammonium phosphate salts. Energy-dispersive spectroscopy reveals that the prepared HAp corresponds to calcium-deficient hydroxyapatite. BC-HAp nanocomposites were prepared by introducing carboxymethylcellulose (CMC) into the bacteria culture media. HAp nanoparticles were then introduced and remained suspended in the culture medium during the formation of cellulose nanofibrils…

Thermogravimetric analysisMaterials scienceBiocompatibilityBiomedical EngineeringAnalytical chemistryBiocompatible MaterialsMicroscopy Atomic ForceBiochemistryCell LineNanocompositesBiomaterialschemistry.chemical_compoundCrystallinityX-Ray DiffractionSpectroscopy Fourier Transform InfraredHumansCelluloseCelluloseMolecular BiologyNanocompositeBacteriaGeneral MedicineThermogravimetryDurapatitechemistryChemical engineeringBacterial celluloseAttenuated total reflectionCarboxymethylcellulose SodiumThermogravimetryPowdersBiotechnologyActa biomaterialia
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Estimation of hydrogen transfer mechanisms in composite materials

2008

Abstract Spill-over effect as a hydrogen transfer mechanism is proposed to explain an increased capacity of hydrogen absorption and improvement of hydrogen activation kinetics in composite material based on the AB5 type metal hydride and powdered glass. A raw lanthanum nickel alloy AB5 with small amount of additives was used as catalyst and bulk material for hydrogen storage, and a borosilicate glass powder with developed surface was applied as a support material. Thermogravimetric technique to determine an absorbed amount of the hydrogen in materials and X-ray powder diffraction analysis for structural investigations was used.

Thermogravimetric analysisMaterials scienceHydrogenHydrideBorosilicate glassComposite numberchemistry.chemical_elementGeneral ChemistryCondensed Matter PhysicsCatalysisHydrogen storagechemistryGeneral Materials ScienceComposite materialPowder diffractionSolid State Ionics
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Structural Characterisation of Complex Layered Double Hydroxides and TGA-GC-MS Study on Thermal Response and Carbonate Contamination in Nitrate- and …

2015

Layered double hydroxides (LDHs) are versatile materials used for intercalating bioactive molecules in the fields of pharmaceuticals, nutraceuticals and cosmetics, with the purpose of protecting them from degradation, enhancing their water solubility to increase bioavailability and improving their pharmacokinetic properties and formulation stability. Moreover, LDHs are used in various technological applications to improve stability and processability. The crystal chemistry of hydrotalcite-like compounds was investigated by X-ray powder diffraction (XRPD), automated electron diffraction tomography (ADT) and thermogravimetric analysis (TGA)-GC-MS to shed light on the mechanisms involved in io…

Thermogravimetric analysishydrotalcytethermal responseInorganic chemistryIntercalation (chemistry)intercationsion exchangeengineering.materialCatalysischemistry.chemical_compoundCrystallinityAdsorptionlayered compoundsOrganic chemistryTGAHydrotalciteIon exchangeChemistryOrganic Chemistryelectron diffraction; intercations; ion exchange; layered compounds; structure elucidationstructure elucidationLayered double hydroxidesstructural characterization hydrotalcyte TGA GC-MS thermal response X-ray powderGeneral ChemistryX-ray powderstructural characterizationengineeringCarbonateelectron diffractionGC-MS
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A new approach to the synthesis of intermetallic compounds: mild synthesis of submicrometric CoxMy (M = Mo, W; x∶y = 3∶1 and 7∶6) particles by direct…

2002

A simple processing route to cobalt–molybdenum and cobalt–tungsten intermetallics (CoxMy, where M = Mo and W, and x∶y = 3∶1 and 7∶6) has been developed, on the basis of the use of precursors resulting from freeze-drying of aqueous solutions of the appropriate common metal salts. The influence of the preparative variables on the outcomes of this procedure is examined. These compounds are prepared as single phases by thermal reduction of amorphous freeze-dried powders under a hydrogen–argon atmosphere (8% H2), followed by slow cooling of the samples. The materials have been characterised by X-ray powder diffraction, metal analysis, scanning electron microscopy and thermogravimetry under an ox…

ThermogravimetryAqueous solutionMaterials scienceScanning electron microscopePowder metallurgySlow coolingMetallurgyMaterials ChemistryIntermetallicGeneral ChemistryPowder diffractionNuclear chemistryAmorphous solidJournal of Materials Chemistry
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Synthesis of new vanadium–chromium and chromium–molybdenum oxynitrides by direct ammonolysis of freeze-dried precursors

2000

Interstitial vanadium–chromium and chromium–molybdenum oxynitrides in the solid solution series V1 − zCrz(OxNy) and Cr1 − zMoz(OxNy) (z = 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been obtained by direct ammonolysis of precursors resulting from the freeze-drying of aqueous solutions of the appropriate metal salts. A study of the influence of the preparative variables on the outcomes of this procedure is presented. Compounds in the V1 − zCrz(OxNy) series are prepared as single phases by nitridation at 1073 K, followed by fast cooling of the samples. Compounds in the Cr1 − zMoz(OxNy) series are prepared as nearly single phases by nitridation at different temperatures, optimized for each composi…

ThermogravimetryChromiumchemistryMolybdenumInorganic chemistryMaterials ChemistryVanadiumchemistry.chemical_elementGeneral ChemistryCrystal structureNitridePowder diffractionSolid solutionJournal of Materials Chemistry
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