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1
Gudmundsdóttir, Anna Dóra. "Photochemistry of some naphthoquinols in solid polymer matrices." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27471.
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The main objective of this work was to study how polymer media can modify the photochemical reactivity of dissolved guest molecules. Three tetrahydronaphthoquinols, whose photochemistry is known to be sensitive to the reaction medium, were synthesized for this study. The photochemistry of these compounds consisted of [2 + 2] cycloaddition in solution and hydrogen abstraction-initiated rearrangement in the solid state. Different photopro-ducts from solution and solid state photolysis were interpreted as being due to reaction from different conformers in the different media.
2,3,4aα,6,7,8aα-hexamethyl-4a,5,8,8a-tetrahydronaphthoquin- l-on-4β-ol, studied in poly(methyl methacrylate) and poly(vinyl acetate) films, was found to exhibit behavior that is intermediate to solution and solid state reactivity and is discontinuous at the glass transition temperature.
2,3,4aα,6,7,8aα-hexamethyl-4a,5,8,8a-tetrahydronaphthoquin-l-on-4α-ol, which was essentially unreactive in the solid state, was also studied. It was found to give the expected but not observed solid state product as the major product in poly(methyl methacrylate).
Finally, 2 , 3 ,4aα ,6,7, 8aα:-4a ,5,8, 8a- tetrahydronaphthoquin-1-on-4β-acetate was studied. As a result of differences in the local enviroment, this compound displayed unique photoreactivity in each of three different media: in solution it gave 5-exo-acetoxy-l,3,4,6,8,9-hexamethyltetracyclo [4.4.0.0[sup 3,9].0[sup 4,8]decan-2-one, in the pure crystalline phase it gave 5-exo-acetoxy-2-oxy-1,3,4,6,8,9-hexamethyltricyclo[4.4.0.0[sup 4,7]-dec-8-en -2-one and in poly(methyl methacrylate) films 5-exo-acetoxy-1,3,4,6,8,9-hexamethyltetracyclo[4.4.0.0[sup 3,7]dec-8-en-2-one, as a major product.
It has been demonstrated that polymer matrices are useful reaction media for reducing the rates of conformational interconversions to the point that alternative chemical processes that are normally too slow to be observed in solution become competitive. This leads to chemical consequences that in some cases mimic those observed in the solid state. In others, where crystals are unreactive for some reasons or where the crystal lattice can sterically impede certain reactions, new products can be formed.Science, Faculty of
Chemistry, Department of
Graduate
2
Burk, Robert C. (Robert Charles) Carleton University Dissertation Chemistry. "Supercritical fluid extraction of trace organics from solid matrices." Ottawa, 1990.
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3
McLean, Alan Stuart. "Transfer matrices and image transport in random media." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307659.
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Lopes, Lidia Velazquez. "Sorption of the platinum-group elements in selected solid matrices." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/4210.
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Summary in English.Bibliography: leaves 70-75.
Recent research on the platinum-group elements (PGE) has shown increased concentrations in environmental samples, probably as a result of the widespread use of PGE (Pt, Pd and Rh in particular) as catalysts in the chemical and car industry. Most of the recent research on PGE focuses on the analysis of concentrations in environmental samples exposed to anthropogenic sources of PGE, but there are very few studies that have investigated sorption behaviour of PGE in soils.
5
Chan, Wai-Chan. "Development of liquid crystalline materials as matrices for polymer composites." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334122.
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Lee, Myung-hyun. "Optoelectronic properties of small silver particles embedded in non-metallic matrices." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314890.
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Phillips, Justin. "Dextrin nanocomposites and deep eutectic solvents as matrices for solid dosage forms." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/81724.
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Controlled-release formulations for pesticide applications act as depot systems that continuously
release the active ingredients into the environment over a speci ed period,
usually from months to years. However, some applications require fast-dissolving drug
delivery. The interest of this research is in fast-release of water-insoluble pesticides into
aquatic environments. This study considered the use of dextrin starch and urea eutectics
as fast release, solid dosage carrier forms that contain an active ingredient. The chosen
active for this study is an acaricide called amitraz (N-methylbis-(2,4-xylyliminomethyl)-
methylamine). The focus is on matrix-based dosage forms such as tablets, granules or
bres that either disintegrate or dissolve to release a water-insoluble active. These types
of dosage forms can be fabricated using processes such as lyophilisation, spray drying,
solvent casting, hot melt extrusion, compression moulding, wet granulation, compaction
and electrospinning. A simple melt-casting procedure has been discussed in the present
work.
Dextrin is a water-soluble form of partially hydrolysed starch and is a promising candidate
matrix material for dissolving solid dosage forms. The molecular weight of the
dextrin was analysed with MALDI-TOF methods and rheological relations. Glycerolplasticized
thermoplastic dextrin-based nanocomposites were prepared with a twin-screw
extrusion-compounding process. The nano llers included a layered double hydroxide
(LDH), cellulose nano bres (CNF) and stearic acid. The time-dependent retrogradation
of the compounds was monitored by X-ray di raction (XRD) and dynamic mechanical
thermal analysis (DMA). XRD showed that the inclusion of stearic acid in the formulations
led to the formation of an amylose-lipid complex and a stable crystallinity during
ageing.
Dissolution rates in water for samples containing dextrin starch, were characterised using
an iodine indicator and UV-visible spectroscopy. High pressure di erential scanning
calorimetry (HPDSC) indicated that the addition of stearic acid led to the formation of
amylose-lipid complexes (ALC's). An additive system containing stearic acid and CNF
was deemed suitable for compounding with amitraz. Compounding at temperatures
above the melting point of the latter led, on dissolution in water, to the release of much
ner particles of the acaricide, which was con rmed with particle size analysis (PSA). The addition of the acaricide caused an apparent increase in the dissolution rate of the
thermoplastic dextrin.
Two eutectic urea systems were considered for casting with amitraz. A eutectic system
of urea and acetamide was found to display a melting point of 44 C at a 37 wt.%
urea composition. The other system consisting of urea and 1,3-dimethylurea displayed a
eutectic point at 32 wt.% urea composition which melted at 59 C. Di erential scanning
calorimetry (DSC), however, con rmed a melting point depression due to a high moisture
content caused by the compounds high hygroscopicity. The endotherm of the sample
containing no excess moisture showed a melting point of 70 C. The 1,3-dimethylurea
system was deemed suitable for casting with amitraz. XRD of the eutectic composition
indicated a small amount of co-crystallisation. The samples were cast as disks of various
diameters while keeping the height of the disks constant. The creation of the cast disks
showed automatic generation of a nely dispersed form of the active through the process
of melting the deep eutectic solvent, the dissolution of the active and its phase separation
on cooling and solidi cation of the eutectic. This implies that ne grinding of the actives
might not be necessary. Eutectic casts containing 20 wt.% amitraz dissolved at a slower
rate than casts not containing the hydrophobic active ingredient. The advantageous
features of these casts were exempli ed using the acaricide incorporated into the urea &
1,3-dimethylurea eutectic.
This work provides two safe, biodegradable and water soluble materials for use as a
matrix to contain active ingredients. One material, the eutectic organic salt casts, can be
produced at low temperatures (<100 C) and can be directly cast into storage containers.
The complete dissolution of the cast compounded with a hydrophilic active is rapid (4-6
min). The second material, a thermoplastic dextrin, was melt compounded in an extruder
at temperatures not exceeding 120 C. This compound containing 20 wt.% of the active
dissolved over a 12 hour period. Dextrin, known to be widely used as an adhesive, will
aid in the adhesion of the active ingredient to the surface where it must be used.Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2019.
PAMSA
Department of Science and Innovation under Grant DST/CON 0004/2019
Chemical Engineering
MEng (Chemical Engineering)
Unrestricted
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Ntola, Chifundo Nyasha Michelle. "Solid lipid matrices for delivery of laundry actives and lipid membrane transport." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12027/.
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The work presented in this thesis reports the preparation and characterisation of novel solid lipid microparticle (SLM) and solid lipid nanoparticle (SLN) systems for applications in delivery of laundry actives and transport of electroactive substances into lipid membranes. The SLM and SLN systems studied are: silicone-loaded SLM, dye-loaded SLM, dual-active SLM (both silicone and dye) and ferrocene-loaded SLN (Fc-SLN). Silicones are used as fabric softeners in laundry applications and dyes are used to enhance the hue of fabrics. The incorporation of two actives into one, dual-active SLM, is a concept that could enable compact formulation and optimized formulation manufacture. The ferrocene-loaded SLN system represent the group of electroactive nanoparticles that could potentially find applications in biosensors, targeted delivery and other biomedical applications. The SLM and SLN systems were prepared using lauric acid as the lipid matrix. Silicone-loaded SLM systems were prepared using solvent-assisted methods with either ethanol or n-hexane as the solvent. They were stabilized with a combination of a primary alcohol ethoxylate (C14-15) (neodol 45-7) and polysorbate 80 (tween 80) as surfactant/co-surfactant). The silicones used were: polydimethylsiloxane (PDMS)(10,000 cST and 100,000 cSt), terminal amino-functionalised silicone (TAS) and a tertiary amino-functionalised silicone (PK10). The dye-loaded SLM systems, incorporating Coomassie Brilliant Blue R (CBB or BB) and ethyl violet (EV, Basic Violet 4) as hueing dyes were prepared using the double emulsion method, also descriptively known as the water-in-oil-in-water (w/o/w) emulsion method. The inner emulsion, w/o was stabilized using a low HLB surfactant, Brij 80 and the outer emulsion o/w was stabilized using a high HLB surfactant, tween 80. For the dual-active SLM system, PK10 silicone was added to the lipid phase before emulsification. The Fc-SLN system was prepared using the solvent emulsification/evaporation method. The surfactants used were poloxamer 188 and tween 80. The lipid membrane systems used were: solid-supported self-assembled monolayer (SAM) and tethered bilayer lipid membrane. The SAM was prepared by chemisorption of a thiolipid, 1,2-dipalmitoyl-sn-glycero-phosphothioethanol (DPPTE) onto a gold surface. Self-assembled monolayers were used as a lower leaflet or tether for the BLM system; an upper leaflet of 1-palmitoyl-2-oloeyl-sn-glycero-3-phosphocholine (POPC) was added by vesicle fusion. The characterisation and penetration of Fc-SLN into lipid membranes was studied using electrochemical methods such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and Resonance Enhanced Surface Impedance (RESI). The SLM and SLN systems where characterised using laser diffraction and dynamic light scattering (DLS) for particle size analysis, optical microscopy and electron microscopy for morphology and particle size, small angle X-Ray Scattering (SAXS) and differential scanning calorimetry (DSC) for crystallinity and structural arrangement and chemical analysis using FTIR, solid state NMR and TGA.
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Cooper, Gail Audrey Ann. "Application of solid-phase extraction for the analysis of drugs in biological matrices." Thesis, University of Glasgow, 1999. http://theses.gla.ac.uk/5368/.
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Experimental mixed-mode solid-phase extraction columns of differing carbon number and carbon loading were investigated for the efficient extraction of drugs of abuse from biological matrices. Methadone and its two major metabolites (EDDP and EMDP) were chosen due to the increase in methadone drug-related deaths in the West of Scotland. Amphetamine and related compounds (methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methyleneidoxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA)) were chosen because of the prevalence of use of "speed" and "ecstasy" throughout the United Kingdom and the challenge these volatile drugs pose to the analyst. Improved methods were developed for the efficient extraction of methadone, EDDP and EMDP from whole blood and for amphetamine and related compounds from whole blood and hair. These methods were successfully applied to the analysis of postmortem samples. The stability of methadone, EDDP and EMDP in whole blood was investigated using the developed extraction method after sorting at various temperatures for a period of six months. Methadone remained stable in blood after six months. This was confirmed by the analysis of postmortem cases samples which when re-analysed within six months of the initial analysis, correlated well. Postmortem hair samples proved useful for determining antecedent drug use history whether extracted by solid-phase extraction or after screening with a Cohort enzyme immunoassay kit, adapted for hair analysis. Solid-phase extraction provides a clean and efficient means of extracting drugs of abuse from whole blood and hair. Simple manipulation of the extraction system (sample pretreatment, pH, derivatisation) provides a versatile alternative to lengthy liquid-liquid extraction techniques and has the added potential of automation.
10
van, Rensburg Wilma. "Characterization of natural antimicrobial peptides adsorbed to different matrices." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97929.
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Thesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Biofouling is the attachment and biofilm formation that leads to negative repercussions such as persistent post-harvest infections, infections obtained from medical implants and continual surface contamination of food processing plants. Much of the problem lies with the resistance that develops against conventional treatments due to the formation of mature biofilms. Thus the focus has shifted from the removal of biofilms to the prevention of initial attachment of organisms. This entails the use of antimicrobial surfaces that either have an inherent antimicrobial activity, e.g. certain metals, or surfaces that are modified by the attachment of antimicrobial agents. The attachment of antimicrobial agents can either be through covalent bonding or adsorption, depending on the intended use of the surface as well as the mode of action of the antimicrobial agent. Antimicrobial peptides (AMPs) are ubiquitous in nature, tend to have a broad spectrum of activity, are very stable and have been shown to maintain activity when covalently bound to solid surfaces. Tyrocidines (Trcs), antimicrobial peptides produced by Bacillus aneurinolyticus, are cyclodecapeptides with a broad spectrum of activity against Grampositive bacteria, fungi, yeasts and the human malaria parasite, Plasmodium falciparum. The aim of this study was to determine the antimicrobial activity of surfaces treated with a tyrocidine extract, under which conditions the activity remained stable and to look into possible applications of these peptide-treated surfaces. The study focussed on different solid surfaces namely mixed cellulose, polyvinylidene fluoride, polycarbonate, cellulose acetate, cellulose (paper)(CL) and high density cellulose packing material (HDC), as a pilot study to assess the antimicrobial activity of Trc and gramicidin S (GS) treated solid surfaces. Peptide desorption and subsequent analysis by mass spectrometry was used to confirm the presence and integrity of the Trcs adsorbed. Scanning electron microscopy was utilised to show that the adsorbed peptides did not affect the structural integrity of the treated filters. However, it was shown that the adsorbed peptides changed the hydrophobic/hydrophilic character by means of a wettability assay. A cell viability assay and erythrocyte assay were developed from existing methodologies to determine the biological activity of the AMP-functionalised polymeric material. Seven of the AMP treated solid surfaces showed antimicrobial activity when challenged with >105 Micrococcus luteus cells/cm2. Although the polycarbonate filter lost antimicrobial activity at the high cell concentrations, it was shown to have potent antimicrobial activity at lower cell concentrations. Complete inhibition of M. luteus growth was observed for both the gramicidin S and tyrocidine extract treated high density cellulose and cellulose filters. Stability tests showed that the tyrocidines remained adsorbed to cellulose filters and biologically active when exposed multiple water washes, water washes at different temperatures (25°C - 100°C) and pH changes (pH 1-12). The antimicrobial activity was only affected after exposure to the water wash of pH 13 which is possible due to susceptibility of the CL filters to high pH solvents. A preliminary study on the effect of Trcs treated CL filters on the sterilization, germination and effect on tomato seedlings was conducted. It was found that Trcs had no effect on the germination and did not fully sterilise the seeds or environment against fungi. However, it was observed that 5 μg/mL Trcs treated filters promoted root length opposed to the toxic effect seen with filters treated with higher Trc concentrations. It is hypothesised that Trcs prefer to bind to hydrophilic surfaces exposing the hydrophobic residues and the cationic residue of the peptide to interact with the bacterial membrane to elicit its antimicrobial response. The exposed residues contain some of the hydrophobic residues and the cationic Orn9/Lys9, which are crucial to the antimicrobial activity of the peptides. Hydrophobic interaction is particularly important for the haemolytic activity which is currently the only viable method of detection of the adsorbed Trcs. Trcs also have a preference for adsorption onto cellulose and cellulose analogues which points to possible application in protective food wrapping and wood surface protection. Trcs maintains its antimicrobial activity regardless of adsorption to solid surfaces. It can therefore be concluded that Trcs treated solid surfaces hold great potential in preventing the initial bacterial colonization and subsequent biofilm formation. Antimicrobial peptide enriched solid surfaces can thus be developed and tailored to a specific application such as filters, catheters and packaging materials.
AFRIKAANSE OPSOMMING: Biovervuiling is die aanhegting en vorming van biofilms met negatiewe gevolge soos aanhoudende na-oes infeksies, infeksies op mediese inplantings en voortdurende oppervlak besoedeling van voedselverwerkings fabrieke. Die probleem lê grotendeels by die weerstand wat ontwikkel word teen konvensionele behandelings as gevolg van die vorming van volwasse biofilms. Die fokus het gevolglik verskuif vanaf die verwydering van biofilms na die voorkoming van aanvanklike aanhegting van organismes aan oppervlaktes. Dit behels die gebruik van antimikrobiese oppervlaktes wat of 'n inherente antimikrobiese aktiwiteit het, bv. sekere metale óf oppervlaktes wat aangepas is deur die aanhegting van antimikrobiese middels. Die aanhegting van antimikrobiese agente kan of deur kovalente binding óf adsorpsie plaasvind, afhangende van die beoogde gebruik van die oppervlak, sowel as die metode van werking van die antimikrobiese agent. Antimikrobiese peptiede (AMPe) is alomteenwoordig in die natuur, is geneig om 'n breë spektrum van aktiwiteit te hê, is baie stabiel en het getoon dat aktiwiteit in stand gehou word wanneer dit kovalent gebind word op soliede oppervlaktes. Tirosidiene (Trcs), antimikrobiese peptiede wat deur Bacillus aneurinolyticus geproduseer word, is siklodekapeptiede met 'n breë spektrum van aktiwiteit teen Gram-positiewe bakterieë, swamme, giste en die menslike malaria parasiet Plasmodium falciparum. Die doel van hierdie studie was om die antimikrobiese aktiwiteit te bepaal van oppervlaktes wat met 'n tirosidien ekstrak behandel is, te bepaal onder watter omstandighede die aktiwiteit stabiel bly en om te soek na moontlike toepassings van hierdie peptied-behandelde oppervlaktes. Die studie het gefokus op verskillende soliede oppervlaktes naamlik gemengde sellulose, polyvinylidene fluoried, polikarbonaat, sellulose asetaat, sellulose (papier)(CL) en 'n hoë digtheid sellulose verpakkings materiaal (HDC), as 'n loodsstudie om die antimikrobiese aktiwiteit van die Trcs en gramisidien S (GS) behandelde soliede oppervlaktes te ondersoek. Peptied-desorpsie en daaropvolgende ontleding deur massaspektroskopie is gebruik om die teenwoordigheid en integriteit van die geadsorbeerde Trcs te bevestig. Skandering elektronmikroskopie is gebruik om aan te toon dat die geadsorbeerde peptiede geen invloed op die strukturele integriteit van die behandelde filters het nie. Daar is egter getoon dat die geadsorbeerde peptiede die hidrofobiese / hidrofiliese karakter verander. „n Lewensvatbaarheid selgebaseerde toets en eritrosiet toets is ontwikkel uit bestaande metodes om die biologiese aktiwiteit van die AMP-gefunktionaliseerde polimeriese materiaal te bepaal. Sewe van die AMP behandel soliede oppervlaktes het antimikrobiese aktiwiteit getoon wanneer dit met > 105 Micrococcus luteus selle/cm2 gedaag is. Hoewel die polikarbonaat filter antimikrobiese aktiwiteit met hoë sel konsentrasies verloor het, is dit getoon dat dit wel uitgeproke antimikrobiese aktiwiteit het teen laer konsentrasies selle. Volledige inhibisie van M. luteus groei is waargeneem vir beide die hoë digtheid sellulose en sellulose filters wat met GS en tirosidien ekstrak behandel is. Stabiliteit toetse het getoon dat die tirosidiene geadsorbeer en biologies aktief op sellulose filters bly nadat dit blootgestel is aan verskeie water was-stappe, waterwasse by verskillende temperature (25 °C -100 °C) en pH veranderinge (pH 1-12). Die antimikrobiese aktiwiteit was net beïnvloed ná blootstelling aan die water met 'n pH 13, wat moontlik is te danke aan die vatbaarheid van die CL filters by hoë pH oplosmiddels is. 'n Voorlopige studie is gedoen om die uitwerking van Trcs behandelde CL filters op die sterilisasie, ontkieming en tamatiesaailinge te bepaal. Daar is gevind dat Trcs geen effek op die ontkieming het nie, maar dat dit nie volledig die sade en omgewing steriliseer vir fungiese groei nie. Daar is egter waargeneem dat 5 μg/mL Trcs behandelde filters wortel lengte van die saailinge bevorder teenoor die giftige uitwerking soos waargeneem vir die filters wat met hoër konsentrasies Trcs behandel is. Dit word gepostuleer dat Trcs verkies om aan hidrofiliese oppervlaktes te bind wat die van die hidrofobiese aminosure en die kationiese residu van die peptied blootstel om aan die bakteriële membraan te bind om gevolglik antimikrobiese reaksie te ontlok. Die blootgestelde deel bevat sommige van die hidrofobiese residue en positiewe Orn9/Lys9 wat noodsaaklik vir die antimikrobiese aktiwiteit van die peptiede. Die hidrofobiese interaksies is veral belangrik vir die hemolitiese aktiwiteit wat tans die enigste bruikbare metode van opsporing van die geadsorbeerde Trcs is. Trcs het ook 'n tendens vir adsorpsie op sellulose en sellulose analoë wat dui op die moontlike toepassing in beskermende voedselverpakking en die beskerming van houtoppervlaktes. Trcs handhaaf hul antimikrobiese aktiwiteit, ongeag van adsorpsie aan soliede oppervlaktes. Dit kan dus afgelei word dat Trcs-behandelde soliede oppervlaktes die potensiaal het om die aanvanklike kolonisasie van bakterië te voorkom en die daaropvolgende biofilm vorming. Antimikrobiese peptied verrykde soliede oppervlaktes kan dus ontwikkel en aangepas word vir gebruik in spesifieke toepassing soos in filters, kateters en verpakkingsmateriaal.
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Amini, Nahid. "Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices." Doctoral thesis, Stockholms universitet, Institutionen för analytisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38625.
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Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrometry (MS) as a detection technique since they influence the ionization yields. It is also important to optimize ionization methods in order to minimize detection limits. In the work this thesis is based upon, selective solid phase extraction (SPE) materials, a restricted access material (RAM) and graphitized carbon black (GCB) were employed for clean up and/or pre-concentration of analytes in plasma, urine and agricultural drainage water prior to liquid chromatography/mass spectrometry (LC/MS). Two SPE formats, in which GCB was incorporated in µ-traps and disks, were developed for cleaning up small and large volume samples, respectively. In addition, techniques based on use of sub-2 µm C18 particles at elevated temperatures and a linear ion trap (LIT) mass spectrometer were developed to improve the efficiency of LC separation and sensitivity of detection of 6-formylindolo[3,2-b]carbazole (FICZ) metabolites in human urine. It was also found that GCB can serve not only as a SPE sorbent, but also as a valuable surface for surface-assisted laser desorption ionization (SALDI) of small molecules. The dual functionality of GCB was utilized in a combined screening-identification/quantification procedure for fast elimination of negative samples. This may be particularly useful when processing large numbers of samples. SALDI analyses of small molecules was further investigated and improved by employing two kinds of new surfaces: oxidized GCB nanoparticles and silicon nitride.
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Angeyo, Hudson. "Development of the Sliding Spark Technique for Trace Analytical Spectroscopy of Dielectric Solid Matrices." Gerhard-Mercator-Universitaet Duisburg, 2004. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-09012004-125159/.
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A novel direct solid-state emission spectroanalytical method based on the pulsed sliding spark source has been developed. The technique is characterised by a radiative transient discharge plasma propagating along the surface of a dielectric solid matrix enforced between a pair of electrodes in air at atmospheric pressure, where matrix excitation is driven by plasma-particle interaction based on geometry- and source opto-electric-modulated electron impact excitation. This dissertation embodies the results of the systematic theoretical and experimental study of the sliding spark which aimed at the analytical development of the technique for trace quantitative spectroscopy of the heavy elements embedded in the dielectric matrix surface layers. The optical emission spectrum, when detected and measured in the wavelength range 212511 nm at about 0.05 nm spectral resolution using optical fibre transmission in conjunction with a holographic blazed grating CCD spectrometer, was found to be suitable for simultaneous multi-elemental analysis. Investigation of the spectral characteristics of several heavy metals embedded in a variety of dielectric matrices (a boro-silicate simulate, borax, polyvinyl-alcohol, cellulose, teflon, Al-Zr simulate ceramic powder, simulate and River sediment samples) has led to the realisation of an empirical scheme for optimal identification and selection of the optically thin lines that are suitable for trace quantitative analysis. The utility of the lines depends on the element and sample matrix. Use of PVC as a matrix modifier results in increased sensitivity through formation of volatile halides. Comprehensive characterisation of the measured spectra provides empirical evidence to exploit the sliding spark at fast pulse frequency also as an atom source for combined emission, fluorescence, and absorption spectroscopy applicable to the elucidation of structural and molecular information by temporal gating, time-resolved techniques. Practical approaches found in the search for an appropriate calibration strategy for quantitative analysis include the use of internal standards based on Y and La (added) and Si and C (matrix-derived) spectral lines, which compensate for the differing ablation yield, signal drifts and matrix effects in and between complex matrices. Accurate analytical models have been derived for Mn, Ti, V, Ni, Co, Cu, Cd, Pb, Cr, Al, Fe, Zn, and Hg. A quantification methodology has been developed based on sediment and as model matrix, which combines high sensitivity and satisfactory reproducibility for Mn, Ti, V, Ni, Co, Cu, Cr, Al, Fe, and Zn. Trace quantitative analysis of dielectric solid matrices by sliding spark spectroscopy is realised in the concentration range from several hundred ppb to thousands of ppm depending on the analyte (and the spectral line utilized) and on the calibration strategy adopted for the quantification. The elemental limits of detection vary from several hundred ppb to few tens of ppm depending on the element, analysed matrix, spectral line, and calibration method. Qualitative speciation analysis is possible for Mn, V, Pb, Ti, Cu, and Co. Sliding spark spectroscopy has been validated as a new, simple but robust and versatile technique for the direct trace analysis of complex solid dielectric and refractory matrices with a reproducibility at 12 %, a precision characterised by a confidence interval of (0.510) %, and an accuracy by relative efficiency of 010 % by the successful analyses of Certified Reference Materials (Stream sediments), sewage sludge, a PVC polymer, an independent XRF laboratory analysis of River Rhine sediment, and by the results of comparative analyses made of the same elements using ICP and XRF (polarised radiation, 3-D Cartesian geometry) techniques.
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Lozada-Garcia, Rolando. "Dynamics and Photodynamics of Acetylacetone in para-Hydrogen matrices." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00780495.
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Acetylacetone (AcAc) exists as a mixture of enol and keto tautomers. Besides providing a good example for the study of tautomerization, it is a model system for investigating intramolecular hydrogen bonds in its enol form. Trapping AcAc in the soft para-Hydrogen (pH2 ) environment brings out new opportunities to investigate its properties. Infrared spectra of the samples give a good characterization of the two stable enol and keto tautomers. The keto/enol ratio in solid pH2 is found to be higher than in other matrices. While vibrational bands of keto are narrow, those of enol are broad, reflecting the intrinsic properties of the enol which exhibits three entangled large amplitude motions (two methyl torsions and the intramolecular hydrogen transfer). Surprisingly, narrowing of some of these bands is observed in a slow time evolution. This effect is interpreted as a consequence of nuclear spin conversion in the hydrogen atoms of the methyl groups, giving access to AcAc species differing by their nuclear spin symmetry. This offers new pertinent investigations on the large amplitude motions, especially on the intramolecular hydrogen transfer. AcAc/pH2 samples have been irradiated by UV laser beams. Irradiation at 266 nm induces isomerization from the stable chelated enol form to non chelated conformers, similarly to the case of other matrices. A clear IR signature of the conformers is obtained thanks to the pH2 host. Irradiation at 248 nm induces the enol/keto tautomerization. The kinetics of this interconversion highlights a non-direct process. Fragmentation is clearly observed under irradiation at 193 nm, followed by chemical reaction with the hydrogen host.
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Banerjee, Upasana. "Mechanistic Investigations into the Photoreactivity of Organic Azides in Solution, Crystals and Cryogenic Matrices." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623250627543686.
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Jimoh, Modupeola A. "Development of hyphenated micro analytical methods for trace metal fractionation and their application to environmentally relevant solid matrices." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980207347.
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Beltran, Carbó Antoni. "Synthesis of novel molecularly imprinted polymers and their application to the solid-phase extraction of water-based matrices." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9049.
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La present tesi s'ha desenvolupat dintre de la línia de recerca que el grup té sobre el desenvolupament de nous sorbents polimèrics per a aplicar-los com a sorbents en extraccions en fase sòlida. En aquest cas, els sorbents sintetitzats són altament selectius per a la molècula d'interès i es coneixen com a sorbents d'empremta molecular.
Pel que fa al mètode de síntesi s'han explorat diferent tipus de polimeritzacions així com diferents tipus d'interacció entre els components que constitueixen el polímer a fi de millorar tant el procés de síntesi com el reconeixement de la molècula objectiu un cop obtingut el polímer per tal d'obtenir extraccions altament selectives.
Aquest sorbents s'han aplicat per a l'extracció de compostos considerats com a contaminants orgànics emergents en mostres tant d'orina humana com aigües de riu o de depuradora amb resultats satisfactoris en tots els casos, demostrant que aquest sorbents són una bona opció a l'hora de realitzar extraccions altament selectives.
The present thesis has been developed within the research trend that the group has on the development of new polymeric materials for their used as sorbents in solid-phase extraction.
In this case, the sorbents synthesised are highly selective for the molecule of interest and are known as molecularly imprinted polymers.
Regarding the synthesis of these polymers, several polymerisation protocols as well as several kinds of interactions that can be established between all the components involved in the synthesis of the polymers have been exploited.
The sorbents obtained were further applied in the selective extraction of several compounds framed within the group of emerging organic pollutants from human urine, river water or effluent water from sewage plants. In any case, a successful extraction of the target analyte was easily achieved by using any of the sorbents developed, thus proving that these sorbents are a good option when aiming to selectively extract the compound of interest from highly complex matrices.
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Andersson, Fräs Annika T. "Determination of volatile sulfur compunds in air and other gas matrices : development and applications of solid-phase microextraction /." Linköping : Univ, 2003. http://www.bibl.liu.se/liupubl/disp/disp2003/arts275s.pdf.
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Young, Douglas Matthew 1996. "The biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in liquid and solid matrices using a prospective consortium." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/288756.
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The biotransformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has been researched in three situations: batch liquid phase, micro soil slurry reactors, and in-situ studies. A prospective consortium of bacteria found in horse manure was used as the primary source of microorganisms. From this consortium, five major strains were isolated. Serratia marcescens, one of the isolates, was found to be the most effective microorganism at biotransforming RDX in liquid phase. The growth and the biotransformation mechanism of RDX were characterized for both the consortium and Serratia marcescens. The biotransformation of RDX from soil matrices was tested in well-mixed micro soil slurry reactors and in undisturbed in-situ reactors. In the micro soil slurry reactors, carbon sources were varied (nutrient broth and corn steep liquor) and different bacteria were inoculated into the systems which already contained bacteria indigenous to the contaminated soil. There were two distinguishable pathways for the biotransformation of RDX in the soil slurry reactors. Different carbon sources promoted the biotransformation through the pathways differently. The addition of inocula to the systems did not provide any benefit as to the biotransformation rates. In the in-situ studies, a lag period of about 50 days was observed before biotransformation of RDX began. This lag period was believed to be due to mass transfer limitation and adaptation time for the bacteria. Again, adding other inocula to the indigenous bacteria did not provide any benefit towards the rate of biotransformation of RDX. In this study, bacteria indigenous to non-contaminated soil was tested as well and found not to biotransform RDX.
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Kalambuka, Hudson [Verfasser], and Alfred [Akademischer Betreuer] Golloch. "Development of the Sliding Spark Technique for Trace Analytical Spectroscopy of Dielectric Solid Matrices / Hudson Kalambuka ; Betreuer: Alfred Golloch." Duisburg, 2006. http://d-nb.info/1193732743/34.
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Liu, Haoyu. "Synthesis and Structure-property Evaluation of Novel Cellulosic Polymers as Amorphous Solid Dispersion Matrices for Enhanced Oral Drug Delivery." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/54934.
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The use of amorphous solid dispersions (ASDs) is an effective and increasingly widely adopted approach for solubility and bioavailability enhancement of hydrophobic drugs. Cellulose derivatives have strong potential as ASD polymers. We demonstrate herein design, synthesis and structure-property relationship characterization of a new series of organo-soluble cellulose omega-carboxyalkanoates for ASDs, by two different synthetic approaches.
These carboxyl-containing cellulose mixed-esters possessed relatively high Tg values with sufficient differences versus ambient temperature, useful to prevent drug mobility and crystallization during storage or transport. Screening experiments were utilized to study the impact of ASD polymers including our new family of cellulose Ω-carboxyesters on both nucleation induction time and crystal growth rate of three poorly soluble model drugs from supersaturated solutions. Attributed to relatively rigid structures and bulky substituent groups, cellulose derivatives were more significant crystallization inhibitors compared to the synthetic polymers. The effective cellulose omega-carboxyesters were identified as possessing a similar hydrophobicity to the drug molecule and high number of ionization groups. Among them, cellulose acetate suberate prepared by us was an extraordinary solution crystal growth inhibitor for ritonavir and its formulated solid dispersions provided a substantial 15-fold enhancement of apparent solution concentration vs. the equilibrium solubility of the crystalline drug. To offset the issue of slow drug release from some cellulose omega-carboxyester based formulations, a new class of amphiphilic cellulosic polymers with hydrophilic oligo(ethylene oxide)-containing side chains was developed via versatile synthetic pathways, and the evaluation of these materials alone or by pairwise polymer blends will be performed as ASD matrices for the enhancement of drug solubility and stability.Ph. D.
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Dillmann, Baudouin. "Electromagnetic fields mapping in the HR-MAS probes, used to perform solid-state NMR at high field." Université Louis Pasteur (Strasbourg) (1971-2008), 2007. https://publication-theses.unistra.fr/public/theses_doctorat/2007/DILLMANN_Baudouin_2007.pdf.
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Shields, Dylan J. "Photochemistry of Organic Azides, Quinones, and Peroxides in Solution, Crystals, Super Molecular Complexes and Cryogenic Matrices." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin157441745178423.
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Allen, Desiree Lisa. "The applications of supercritical fluid and solid-phase extraction techniques for the recovery of drugs of abuse from biological matrices." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249963.
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Ledain, Olivier. "Elaboration de matrices céramiques par un nouveau procédé hybride : imprégnation de poudres et CVI réactive." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0177/document.
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Les composites à matrice céramique ont initialement été développés pour des applications aérospatiales, aéronautiques militaires ou énergétiques en raison de leurs bonnes propriétés à haute température. Ils sont généralement fabriqués par le procédé CVI (Chemical Vapour Infiltration). Un nouveau procédé hybride combinant l’imprégnation de poudre au sein de préformes, suivie de la CVI Réactive(RCVI), est proposé afin de réduire les temps de production. Cette voie est basé sur l’adaptation du procédé RCVD à l’infiltration en milieu poreux. En RCVD, l’absence d’une partie des éléments du dépôt de carbure dans la phase gazeuse implique une consommation/conversion du substrat solide. Dans cette étude, la croissance et la consommation associée ont été étudiées en fonction de divers paramètres dans le système chimique Ti-H-Cl-C. Cette étude est accompagnée d’analyses (DRX, XPS, IRTF) des produits issus de la réaction chimique de formation du TiC. Ensuite, la conversion partielle d’une poudre de carbone submicronique enTiC et la consolidation des zones compactes de poudre par l’infiltration RCVI utilisant le mélange gazeux H2/TiCl4 a été étudiée. La porosité résiduelle et la teneur en TiC ont été mesurées par analyse d’image à différentes distance de la surface des matériaux. Selon la température, plusieurs centaines de micromètres infiltrés ont été obtenus. Finalement, les résultats ont été transposés à l’infiltration RCVI de préformes type CMC. Malgré une teneur minimale de 25% de TiC dans l’ensemble de la préforme, les résultats montrent une mauvaise homogénéité d’infiltration et une mauvaise cohésion des blocs de poudre consolidés avecles fibres de leurs environnementsCeramic matrix composites were originally developed for aerospace,military aeronautics or energyapplications thanks to their good properties at high temperature. They are generally made by ChemicalVapor Infiltration (CVI). A new short hybrid process combining fiber preforms lurry impregnation ofceramic powders with an innovative Reactive CVI (RCVI) route is proposed to reduce the productiontime. This route is based on the combination of Reactive Chemical Vapour Deposition (RCVD), whichis often used to deposit coatings on fibres, with the Chemical Vapor Infiltration (CVI).In RCVD, the absence of one element of the deposited carbide in the initial gas phase involves theconsumption/conversion of the solid substrate. In this work, the RCVD growth and the associatedconsumption were studied with different parameters in the Ti-H-Cl-C chemical system. The study hasbeen completed with the chemical products analysis, combining XRD, XPS and FTIR. Then, the partialconversion of sub-micrometer carbon powders into titaniumcarbide and the consolidation of greenbodies by RCVI from H2/TiCl4 gaseous infiltration were studied. The residual porosity and the final TiCcontent were measured in the bulk of the infiltrated powders by image analysis from scanning electronmicroscopy. Depending on temperature, few hundred micrometers-depth infiltrations are obtained.Finally, the results have been transposed to the RCVI into CMC-type preforms. Despite aminimalTiC content of 25% in the overall preform, the results shown a bad homogeneity of the infiltration anda poor cohesion of fibres with RCVI consolidated powder of their environment
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Windbergs, Maike. "Towards a better understanding of lipid based matrices innovations in the production and analysis of physically stable solid lipid extrudates with tailor-made dissolution profiles." Göttingen Cuvillier, 2009. http://d-nb.info/996511962/04.
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Krausova, Rambure Katerina. "Vers de nouvelles matrices minérales pour l’immobilisation et la valorisation des déchets ultimes de l’incinération des déchets ménagers." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1118/document.
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L'objectif général de cette thèse est de transformer les déchets ultimes et dangereux contenant des métaux lourds, en matières minérales chimiquement stables. L'augmentation de la production des ordures ménagères (OM) est un problème qui concerne et préoccupe le monde entier. Parmi les différentes méthodes de traitement des déchets municipaux, l'incinération est une technologie qui peut fournir une solution efficace et respectueuse pour l'environnement. Le problème de ce traitement est la production de REFIOM. Les REFIOM peuvent contenir de grandes quantités de composés métalliques toxiques et est considéré comme un déchet dangereux ce qui oblige à les mettre en décharges classées. Trois types de matériaux pour l'immobilisation du plomb et du cadmium ont été étudiés : les vitrocéramiques, les céramiques frittées et les géopolymères. Nous sommes parvenus à synthétiser une base de vitrocéramique à partir de cendres incinérées purs et nous avons diminué sa volatilisation lors de sa production. Des résultats prometteurs ont été obtenus pour la vitrocéramique Ca-Mg-Si-O qui a incorporé durablement une quantité élevée de cadmium dans les structures cristallines et le plomb dans la structure amorphe. La phase cristalline est plus résistante à l'attaque acide en raison de son incorporation dans une matrice vitreuse qui génère une double protection. Ses travaux ouvrent la possibilité de créer cette matrice en ajoutant des oxydes commerciaux aux résidus d'incinération. Nous avons étudié la céramique frittée à base du système Ba-Mg-Ti-O. Nous avons obtenu les trois phases minérales présentées dans la céramique SYNROC (hollandite, pérovskite et rutile) où le cadmium substitue le magnésium tandis que le plomb a occupé le site appartenant au baryum. La céramique frittée est satisfaisante en termes d'immobilisation des métaux lourds avec de bonnes propriétés physiques. Pour produire des géopolymères résistants à partir de REFIOM, il est avantageux d'utiliser un rapport L/S = 1,2 et de les sécher à température ambiante. Il a été observé que le frittage influence le taux de réorganisation structurelle avec l'apparition de la phase sodalite ( Na4Si3Al3O12Cl), qui se compose de tunnels où les métaux lourds peuvent être incorporés. Le plomb et le cadmium restent largement en dessous de la limite des normes TCLP. Le traitement thermique à plus de 500°C augmente la densité de l'échantillon. Lorsque les REFIOM sont mélangés avec d'autres types de déchets tels que des MIOM ou du calcin, il est possible d'augmenter la résistance chimique et mécanique. Nous avons conclu que les trois matrices de stockages étudiées offrent de bonne perspective pour l'immobilisation du plomb et du cadmiumThe overall objective of this thesis is to transform ultimate and hazardous waste containing heavy metals, into chemically stable mineral materials. The increasing municipal solid waste (MSW) generation is a problem ranging to global concern. Among various MSW treatment methods, incineration is a technology, which may provide an efficient and environmental friendly solution. Problem of this treatment is the production of fly ash. Fly ash may contain large amounts of toxic metal compounds and is considered as hazardous waste with obligation of final disposal into specialized landfills. Three types of materials for immobilization of lead and cadmium have been investigated: glass ceramics, sintered ceramics and geopolymers. We manage to synthetize a glass-ceramic based purely on the incinerated ashes and to decrease the volatilization during its production. Promising results have been obtained for Ca-Mg-Si-O bearing glass-ceramic with high sustainable incorporation of cadmium into crystalline structures and lead into an amorphous structure. Crystalline structure was evaluated being more resistant against acid attack because of its embedding into a glass matrix that generates a double protection. The future research should be done on possibility obtaining this phase by addition of commercial oxides into fly ash. Sintered ceramic investigated was based on Ba-Mg-Ti-O system. We obtained three mineral phases presented in SYNROC (hollandite, perovskite and rutile) where cadmium substituted the site of magnesium while lead occupied the site belonging to barium. The sintered ceramic is satisfactory in terms of toxic elements incorporation and of chemical and mechanical resistance. For production of resistant geopolymer from fly ashes, it is favorable to use ratio L/S =1.2 and drying at room temperature. It was observed that sintering affects the rate of structural reorganization with apparition of sodalite phase (Na4Si3Al3O12Cl), which consists of tunnels where heavy metals can be incorporated. Lead and cadmium stay mainly below the limit of TCLP standards. The heat treatment over 500°C increases density of the sample. When fly ash mixed with other types of waste such as bottom ash or waste glass powder, it is possible to obtain a more resistant. It was found that all three matrices are a good prospect for a stabilization technique with respect to the major pollutants lead (Pb) and cadmium (Cd)
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Heilig, Andrej [Verfasser]. "The interaction of aroma compounds and dairy constituents: influence of composition and processing on aroma retention and transport in liquid to semi-solid matrices / Andrej Heilig." München : Verlag Dr. Hut, 2013. http://d-nb.info/1033041289/34.
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Samsoen, Simon. "Synthèses et caractérisations physiques de matrices polymères pour la formulation de dispersions solides amorphes curcumine/polyvinylpyrrolidone." Electronic Thesis or Diss., Université de Lille (2022-....), 2024. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2024/2024ULILR001.pdf.
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L'objectif de ce travail de thèse est d'améliorer la connaissance fondamentale des mécanismes intervenant dans la formation de dispersions solides amorphes (DSA) d'un principe actif pharmaceutique au sein d'un excipient polymère, en particulier l'impact de l'architecture macromoléculaire des polymères sur la stabilité physique des DSA.Des polymères de poly(N-vinylpyrrolidone) (PVP) de faible dispersité, de masses molaires et fonctionnalités d'extrémités de chaînes différentes sont d'abord synthétisés de façon contrôlée par RAFT/MADIX (Reversible Addition-Fragmentation chain Transfer/ Macromolecular design by Interchange of Xanthates). Ils sont ensuite utilisés pour la formulation, par co-broyage et évaporation de solvant, de mélanges à base de curcumine (CUR). La caractérisation physico-chimique avancée du PVP, de la CUR et des DSA obtenues nous permet d'établir le diagramme de phases (courbe de solubilité) et d'états (évolution de la température de transition vitreuse (Tg)) CUR/PVP. Ce diagramme permet, d'une part, de mieux comprendre les conditions de stabilité des DSA CUR/PVP et l'impact de la masse molaire ou de la fonctionnalité des extrémités de chaînes du PVP. D'autre part, la comparaison avec des DSA formulées avec du PVP commercial de forte dispersité nous permet d'établir le rôle particulier de la dispersité sur la Tg du PVP et celle des DSA CUR/PVP. En effet, dans le cas de DSA formulées avec du PVP de forte dispersité, les résultats montrent une diminution de Tg pour des taux élevés de PVP qui dévoile une compétition entre le développement d'interactions attractives entre CUR et PVP et un effet plastifiant engendré par la grande distribution des masses molaires du PVP. Enfin, ce travail révèle que l'utilisation de PVP synthétisés de façon contrôlée permet d'obtenir des DSA stables sur un domaine de températures et de concentrations en curcumine plus étendu que pour des DSA formulées avec un PVP industriel de forte dispersitéThis thesis aims at improving our fundamental knowledge on the mechanisms involved in the formation of amorphous solid dispersions (ASD) of a drug within a polymer excipient, in particular the impact of the macromolecular architecture on the physical stability of ASD.Poly(N-vinylpyrrolidone) (PVP) polymers with low dispersity and different molar masses and chain-end functionalities are first synthesised in a controlled manner by RAFT/MADIX (Reversible Addition-Fragmentation chain Transfer/ Macromolecular design by Interchange of Xanthates). They are then used to formulate, by co-milling and solvent evaporation processes, mixtures with curcumin (CUR). The advanced physico-chemical characterisation of PVP, CUR and the obtained ASD enables us to establish the CUR/PVP phase (solubility limit) and state (glass transition temperature (Tg) evolution) diagrams. On the one hand, this diagram allows us to better understand the stability conditions of CUR/PVP ASD and the impact of the PVP molar mass and chain-end functionality. On the other hand, comparison with ASD formulated with high dispersity commercial PVP allows us to highlight the specific role of the dispersity on the Tg of PVP and of CUR/PVP ASD. Indeed, for ASD formulated with high dispersity PVP, results show the decrease of Tg at high PVP contents, which unveils a competition between the development of attractive interactions between CUR and PVP and a plasticising effect induced by the broad distribution of PVP molar masses. Finally, this work reveals that the use of PVP synthesised in a controlled manner allows to obtain stable ASD over a broader range of temperatures and CUR concentrations than for ASD formulated with industrially available PVP of high dispersity
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Mejait, Anouar. "Evaluation of the environmental fate and impact of organic contaminants using innovative approach coupling high-throughput methods." Electronic Thesis or Diss., Perpignan, 2024. http://www.theses.fr/2024PERP0034.
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Les contaminants organiques sont des substances nocives présentes dans l'environnement qui peuvent affecter la santé humaine et les écosystèmes. Parmi eux, les composés pharmaceutiques et les pesticides sont liés à de nombreuses maladies chez l'homme. Ils peuvent également affecter des espèces non-cibles dans l'environnement. Dans le cas des pesticides, largement utilisés en agriculture, des alternatives sont à l'étude. Les biopesticides, qui sont des substances complexes dérivées de sources naturelles, représentent une alternative aux pesticides. Ils sont présumés moins nocifs ; cependant, les réglementations actuelles ne sont pas bien adaptées à ces substances. Par conséquent, de nouveaux paramètres doivent être développés pour étudier le devenir et l'impact des biopesticides. Au sein de l'unité de recherche CRIOBE, une nouvelle méthode appelée « Environmental Metabolic Footprinting » (EMF) a été développée. Cette méthode repose sur l'utilisation de la métabolomique non-ciblée par LC-MS afin d'étudier le devenir et l'impact environnemental des substances complexes comme les biopesticides, en analysant le méta-métabolome de la matrice environnementale, qui comprend à la fois l'endométabolome (métabolome de la matrice environnementale) et le xénométabolome (composés contaminants organiques et leurs produits de dégradation). L'objectif de ma thèse était d'apporter de nouveaux développements à l'approche EMF afin de mettre en place une approche pour l'évaluation des risques environnementaux (ERA) des contaminants organiques dans les matrices environnementales des sols et des sédiments. De nouveaux paramètres ont été mis en place et des approches supplémentaires -omiques ont été introduites. Dans le premier chapitre, je me concentre sur la détermination de la méthode d'extraction chimique optimale et du kit d'extraction d'ADN optimal pour analyser le devenir et l'impact des contaminants organiques dans les matrices de sédiments. Quatre méthodes d'extraction chimique ont été comparées, et pour l'extraction d'ADN, cinq kits commerciaux ont été testés. En utilisant les résultats de la LC-MS, j'ai identifié la méthode d'extraction chimique optimale et, en analysant les métriques de diversité alpha et bêta, le meilleur kit d'extraction d'ADN a été sélectionné. Le deuxième chapitre se concentre sur le développement d'un flux de travail statistique pour étudier le devenir des contaminants organiques tels que les biopesticides (par exemple, Beloukha). Ce flux de travail inclut le développement d'un nouveau paramètre, le temps de dissipation, qui correspond au temps nécessaire à la dissipation des contaminants organiques. Une expérience cinétique de 57 jours a été menée sur une matrice de sol (microcosme) et le bioherbicide Beloukha. En utilisant un flux de travail ad hoc et des scripts développés, nous avons pu extraire les composés biopesticides du méta-métabolome et déterminer le temps de dissipation de Beloukha. Dans le troisième chapitre, je me concentre sur l'impact de Beloukha sur la biodiversité. Le métabarcoding bactérien et eucaryote a été réalisé. Les résultats montrent que les composés biopesticides ont un impact significatif sur les bactéries et les microeucaryotes, alors qu'aucun effet significatif n'a été observé sur les métazoaires. De plus, nous avons pu identifier les taxons spécifiques impactés et les métabolites responsables. En conclusion, ce travail a permis d'apporter des améliorations significatives à l'approche EMF, la rendant plus intégrative et adaptée à l'étude du devenir et de l'impact des contaminants organiques dans différents types de matrices (sol, sédiment, etc.). L'introduction de l'approche génomique permettra de déterminer plus en détail l'impact des contaminants organiques sur la biodiversité. Les nouveaux développements, contribueront à mettre à jour les réglementations existantes, les rendant plus adaptées aux substances complexes et garantissant l'utilisation sécurisée des biopesticidesOrganic contaminants are harmful substances present in the environment that can affect human health and ecosystems. Among them, pharmaceutical compounds and pesticides, are linked to many diseases in humans, such as cancer, respiratory disorders, and neurological disorders. They can also affect non-target species in the environment, including beneficial insects. In the case of pesticides, widely used in agriculture and other fields, alternatives are under consideration. Biopesticides, which are complex substances derived from natural sources such as plants and microorganisms, present a promising alternative to pesticides. They are presumed to be less harmful; however, the existing regulations are not well adapted to these substances, and current parameters, like DT50 and DT90, are not suitable for studying the degradation of biopesticides. Therefore, new parameters need to be developed to study the fate and impact of biopesticides. At CRIOBE research unit, a new method called Environmental Metabolic Footprinting (EMF) has been developed. This method is based on the use of non-target metabolic LC-MS in order to study the environmental fate and impact of organic contaminants and in particularly complex substances like biopesticides by analyzing the environmental matrix meta-metabolome, which includes both the endometabolome (environmental matrix metabolome) and the xenometabolome (organic contaminant compounds and their degradation products). The aim of my PhD was to bring new developments to the EMF approach in order to set up an approach for the Environmental Risk Assessment (ERA) of organic contaminants in soil and sediment environmental matrices. New parameters were set-up and additional -omics approaches were introduced. In the first chapter, I focus on determining the optimal chemical extraction method and the optimal DNA extraction kit for analyzing the fate and impact of organic contaminants in sediment matrices. Four chemical extraction methods were compared, and for DNA extraction, five commercial kits were tested. Using LC-MS results, I identified the optimal chemical extraction method, and by analyzing alpha and beta diversity metrics, the best DNA extraction kit was selected. These findings will make the EMF approach suitable and well-adapted for studying organic contaminants in sediment matrices. The second chapter centers on the development of a statistical workflow to study the fate of organic contaminants such as biopesticides (e.g., Beloukha). This workflow includes the development of a new parameter, dissipation time, which corresponds to the time required for the dissipation of organic contaminants. A 57-day kinetic experiment was conducted on a soil matrix (microcosm) and the bioherbicide Beloukha. Using ad-hoc workflow and develo pedscripts, we were able to extract biopesticide compounds from the meta-metabolome and determine the dissipation time of Beloukha. In the third chapter, I focus on the impact of Beloukha on biodiversity. Bacterial and eukaryotic metabarcoding (16S and 18S Ribosomal ribonucleic acid (rRNA) genes) were performed. The results show that biopesticide compounds significantly impacted bacteria and microeukaryotes, whereas no significant effect was observed on metazoa. Additionally, we were able to identify the specific taxa impacted and the metabolites responsible. In conclusion, this work has led to significant improvements in the EMF approach, making it more integrative and suitable for studying the fate and impact of organic contaminants in different types of matrices (soil, sediment, etc.), the introduction of genomic approach will help to determine in more details the impact of the organic contaminant on biodiversity. The new developments such as dissipation time will help update existing regulations, making them more suitable for complex substances and ensuring the safe use of biopesticides to preserve ecosystem balance
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Virey, Eric. "Étude de nouvelles matrices susceptibles d'émettre dans l'infrarouge moyen entre 3 et 5 µm : synthèse et caractérisation de CsCdBr3." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0157.
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Dans le domaine des lasers, il existe une demande importante concernant la mise au point de sources capables d'emettre dans la bande spectrale s'etendant de 3 a 5 m, pour la detection de gaz et certaines applications militaires. A l'heure actuelle, les sources laser disponibles dans cette fenetre de transparence de l'atmosphere sont constituees d'oscillateurs parametriques optiques (o. P. O) ou de diodes lasers a multipuits quantiques. Dans l'objectif de developper des sources compactes et susceptibles de fonctionner en continu a temperature ambiante, nous avons explore la voie des materiaux solides dopes par des ions optiquement actifs. Apres avoir justifie le choix du cscdbr#3 dope avec des terres rares, ce manuscrit decrit la synthese et la caracterisation physique de ce materiau, dont les inconvenients majeurs s'averent etre la faible conductivite thermique et la grande fragilite mecanique. L'elaboration et la mise en place des divers procedes de synthese sous forme de poudre, ainsi que la croissance de lingots monocristallins et le conditionnement du materiau sont decrits. Excites dans le proche infrarouge entre 800 et 1000 nm, les cristaux de cscdbr#3 : tr (tr = pr, nd, dy, ho, er, tm) presentent de nombreuses bandes d'emission couvrant l'ensemble de la gamme spectrale 3-5m et meme au dela. Ces resultats originaux s'expliquent par la faible energie de phonons de la matrice. Neanmoins, bien qu'etant une condition necessaire, cette propriete peut, comme l'a revele l'etude des dynamiques de transitions, etre nefaste a l'obtention d'une emission stimulee en continu. On constate en effet souvent, qu'elle induit des durees de vie importantes des niveaux recepteurs de ces transitions, et peut egalement limiter l'efficacite de pompage, lorsque celui ci ne s'effectue pas directement sur le niveau emetteur.
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Waysek, Edward H. "Caractérisation de caroténoi͏̈des à l'état solide dans des matrices organiques." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13111.
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Beltiukov, Iaroslav. "Matrices aléatoires et propriétés vibrationnelles de solides amorphes dans le domaine terahertz." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTS018/document.
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Il est bien connu que divers solides amorphes ont de nombreuses propriétés universelles. L'une d'entre elles est la variation de la conductivité thermique en fonction de la température. Cependant, le mécanisme microscopique du transfert de chaleur dans le domaine de température supérieure à 20 K est encore mal compris. Simulations numériques récentes du silicium et de la silice amorphes montrent que les modes de vibration dans la gamme de fréquences correspondante (au-dessus de plusieurs THz) sont délocalisés. En même temps ils sont complètement différents des phonons acoustiques de basse fréquence, dits « diffusions ».Dans ce travail, nous présentons un modèle stable de matrice aléatoire d'un solide amorphe. Dans ce modèle, on peut faire varier le degré de désordre allant du cristal parfait jusqu'au milieu mou extrêmement désordonné sans rigidité macroscopique. Nous montrons que les solides amorphes réels sont proches du deuxième cas limite, et que les diffusions occupent la partie dominante du spectre de vibration. La fréquence de transition entre les phonons acoustiques et diffusons est déterminée par le critère Ioffe-Regel. Fait intéressant, cette fréquence de transition coïncide pratiquement avec la position du pic Boson. Nous montrons également que la diffusivité et la densité d'états de vibration de diffusons sont pratiquement constantes en fonction de la fréquence. Par conséquent, la conductivité thermique est une fonction linéaire de la température dans le domaine allant à des températures relativement élevées, puis elle sature. Cette conclusion est en accord avec de nombreuses données expérimentales. En outre, nous considérons un modèle numérique de matériaux de type de silicium amorphe et étudions le rôle du désordre pour les vibrations longitudinales et transverses. Nous montrons aussi que la théorie des matrices aléatoires peut être appliquée avec succès pour estimer la densité d'états vibrationnels des systèmes granulaires bloquésIt is well known that various amorphous solids have many universal properties. One of them is the temperature dependence of the thermal conductivity. However, the microscopic mechanism of the heat transfer above 20 K is still poorly understood. Recent numerical simulations of amorphous silicon and silica show that vibrational modes in the corresponding frequency range (above several THz) are delocalized, however they are completely different from low-frequency acoustic phonons, called “diffusons”.In this work we present a stable random matrix model of an amorphous solid. In this model one can vary the strength of disorder going from a perfect crystal to extremely disordered soft medium without macroscopic rigidity. We show that real amorphous solids are close to the second limiting case, and that diffusons occupy the dominant part of the vibrational spectrum. The crossover frequency between acoustic phonons and diffusons is determined by the Ioffe-Regel criterion. Interestingly, this crossover frequency practically coincides with the Boson peak position. We also show that, as a function of frequency, the diffusivity and the vibrational density of states of diffusons are practically constant. As a result, the thermal conductivity is a linear function of temperature up to rather high temperatures and then saturates. This conclusion is in agreement with numerous experimental data.Further, we consider a numerical model of amorphous silicon-like materials and investigate the role of disorder for longitudinal and transverse vibrations. We also show that the random matrix theory can be successfully applied to estimate the vibrational density of states of granular jammed systems
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Maciel, Lavra Zênia Maria. "Incremento da solubilidade e da cinética de dissolução do fármaco Efavirenz através da obtenção de misturas binárias amorfas com matrizes poliméricas." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2016. http://www.theses.fr/2016EMAC0011/document.
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L’amélioration de la solubilité des principes actifs peu solubles est devenue l’un des principaux challenges de l’industrie pharmaceutique. Bien que présentant une structure chimique potentiellement idéale pour interagir avec la cible, elles échouent dans l’efficacité in vivo : après administration, elles ne peuvent se dissoudre dans les milieux aqueux biologiques et par conséquent ne peuvent être transportées sur leur site d’action pour atteindre la concentration efficace, amenant à un échec thérapeutique. De nombreuses stratégies très intéressantes ont été proposées pour surmonter ce sérieux obstacle. Les dispersions solides sont étudiées depuis plus de 40 ans et ont conduit à de très nombreuses publications mais jusqu’à aujourd’hui peu de produits ont été commercialisés principalement pour des raisons de stabilité physico-chimique. Celles-ci ont pour but de présenter le principe actif sous sa forme amorphe car cette forme solide présente un état d’énergie plus élevé et par conséquent une solubilisation facilitée. Par ailleurs, le système doit rester stable durant le stockage, ainsi la recristallisation ou tout autre changement entraînant une modification du profil de libération doivent être évités. Différentes techniques de production peuvent être utilisées pour préparer les dispersions solides comme l’extrusion à chaud ou l’atomisation-séchage. Le principal objectif de ce travail a été d’améliorer la solubilité de l’Efavirenz (EFV), un principe actif peu soluble dans l’eau, par sa dispersion dans une matrice polymère en utilisant la technique d’atomisation-séchage. Différents polymères ont été utilisés : Soluplus®, PVPVA64 et HPMCAS. Des mélanges binaires EFV-polymère (Soluplus®, PVPVA64 et HPMCAS) ont été générées et caractérisées. Les techniques de caractérisation utilisées ont été la calorimétrique différentielle modulée, la diffraction des rayons X, l’analyse Raman et la spectroscopie infrarouge à transformée de Fourier et l’analyse de sorption de vapeur pour la caractérisation physicochimique de l’état solide des mélanges binaires. L’étude de caractérisation a été complétée par une étude de solubilité et de dissolution dans différents milieux aqueux ainsi que de stabilité dans différentes conditions de stress de température et humidité relative. Les résultats ont mis en évidence la formation de dispersions solides amorphes avec les trois polymères utilisés. Les différents profils de libération obtenus à partir des mélanges binaires générés dans ce travail montrent l’influence du type de polymère, de la concentration du principe actif dans les dispersions solides et de la composition du milieu de dissolution sur la fonctionnalité des produits (solubilité, dissolution)Poor aqueous solubility has become a property of numerous new drug candidates causing major concern. Despite a potentially ideal chemical structure allowing for interaction with the target, these substances fail to be effective in vivo: upon administration, they cannot dissolve sufficiently in the aqueous fluids of the body and, thus, cannot be transported to their site of action to reach therapeutically effective concentrations. Various interesting strategies have been proposed to overcome this crucial hurdle. Solid dispersions have been studied for more than 40 years and lead to numerous interesting research articles. However, today, only a few products have reached the market principally due to problems with the physico-chemical stability. The idea is to transform the crystalline raw material into a physical state having a greater energy in order to increase the driving force for drug dissolution. At the same time, the system should be stable during long term storage, thus, re-crystallization or other system changes, resulting in altered drug release rates, must be avoided. Different manufacturing techniques can be used to prepare such polymeric systems, including hot-melt extrusion and spray-drying. The main objective of this work has been to improve Efavirenz (EFV) solubility by forming solid dispersions using the spray-drying technique. In this study EFV has been incorporated into hydrophilic polymeric matrices Soluplus®, PVPVA64 and HPMCAS to increase its aqueous solubility. Binary mixtures EFV-Soluplus®, EFV-PVPVA64 and EFV-HPMCAS) were produced and characterized using SEM, X-ray diffraction, DSC, RAMAN, Infrared spectroscopy and water vapor sorption. This physicochemical characterization was completed by solubility and in vitro dissolution studies at different stress conditions (temperature, RH). The results obtained confirmed the formation of amorphous solid dispersions for all studied drug-polymer combinations. The different kinetic profiles obtained from the various solid dispersions generated in this work showed the influence of the type and polymer and drug-polymer binary mixture composition and in vitro dissolution medium on the functionality of spray-dried solid dispersions produced in this work (solubility and dissolution kinetics)
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HEIMENDINGER, JOHN. "Matrices semi-solides en gelules a base d'acide acetyl-salicylique : formulation, remplissage sur machine et biodisponibilite chez l'homme." Strasbourg 1, 1987. http://www.theses.fr/1987STR15002.
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MARIALVA, NETO ANTONIO A. "Incorporacao de residuos solidos galvanicos em matrizes vitreas." reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11128.
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Made available in DSpace on 2014-10-09T12:48:41Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T13:57:51Z (GMT). No. of bitstreams: 1 09243.pdf: 4447500 bytes, checksum: 56bd93824762b36bf0679726866107aa (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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VERDEAU, TRUFFIER CAROLINE. "Influence des conditions d'elaboration sur la zone interfaciale de materiaux composites hautes performances a matrice thermoplastique." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0117.
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Microstructure et proprietesmecaniques de composites unidirectionnelles polyetherethercetone/ fibres carbone, sulfure de polyphenylene/fibres de carbone et polyetherimide/fibre de carbone. Influence de temps rapide, refroidissement lent etc. Essais mecaniques. Cohesion interne. Mise en evidence d'une phase "transcristalline". Modelisation du comportement viscolastique
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HAMPAI, DARIUSH. "Metodologie per la rivelazione e il riconoscimento di impurezze solide mediante sorgenti X : caratterizzazione di materiali complessi con applicazione al caso della matrice solida dell'acqua." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/982.
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I ghiacciai sono un naturale sistema di immagazinamento di dati climatologici, che consente attraverso le precipitazioni di raccogliere in serie temporalmente ordinate le particelle provenienti dalla circolazione atmosferica. A questo proposito, l'identificazione di polvere mineralogia svolge un ruolo chiave. In questa tesi, partecipo ad un esperimento preliminare di spettroscopia di assorbimento X (XAS) di minerali di polvere estratte da carote di ghiaccio antartico e alpino sulla soglia del Fe. Nella tesi viene descritta una camera sperimentale da alto vuoto, progettata e realizzata per lo studio della fluorescenza e assorbimento X anche ad incidenza radente. Presso lo Stanford Synchrotron Radiation Lightsource (SSRL), sono state effettuate misure di fluorescenza e assorbimento X di materiali a bassissime concentrazioni. I risultati mostrano che questa tecnica sperimentale permette il riconoscendo di inclusioni di ferro (dell'ordine di 1-10 ug) nel particolato insolubile .
Inoltre, presso i Laboratori Nazionali di Frascati dell'INFN, con il mio contributo è stato progettato, sviluppato e realizzato, un sistema di micro-spettroscopia, discusso nella tesi, al fine di raggiungere una mappatura di micro-fluorescente X (uXRF) con una risoluzione spaziale di chi 100x100 um. Questo apparecchio permette anche di effettuare "Imaging" (con radiazione non coerente), per mezzo di un ingrandimento del settore in analisi mediante lenti rifrazione (CRL).Aeolian mineral dust archived in polar and mid latitude ice cores represents a precious proxy for assessing environmental and climatic variations at different timescales. In this respect, the identification of dust mineralogy plays a key role. In this thesis, I partecipate in preliminary X-ray absorption spectroscopy (XAS) experiments on mineral dust particles extracted from Antarctic and from Alpine firn cores at the Fe K-edge. A dedicated high vacuum experimental chamber was set up for normal-incidence and X-Ray Fluorescence (normal and total-reflection configuration) and Absorption Spectroscopy analyses on minor amounts of mineral materials at the Stanford Synchrotron Radiation Lightsource. Results show that this experimental technique and protocol allows recognizing iron inclusion mineral fraction on insoluble dust in the 1-10 ug range. Moreover, at the "Laboratori Nazionali di Frascati" of INFN, with my contribution has been designed, developed and done, a system of micro-spectroscopy, discussed in the thesis, in order to achieve a mapping in micro-fluorescent X (uXRF) with a spatial resolution of about 100x100 um. This apparatus allows also to carry "imaging" (with radiation not coherent), by means of a magnification of the area in analysis by means of lenses refractive (CRL).
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Monerie, Yann. "Fissuration des matériaux composites : rôle de l'interface fibre-matrice." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22054.
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Le, Maître Johann. "Développement de la spectrométrie de masse à ultra- haute résolution associée à la spectrométrie de mobilité ionique pour la caractérisation de coupes pétrolières lourdes. structural analysis of heavy oil fractions afterr hydrodenitrogenation by high-resolution tandem mass spectrometry and ion mobility spectrometry Structural analysis of neutral nitrogen compounds refractory to the hydrodenitrogenation process of heavy oil fractions by high-resolution tandem mass spectrometry and ion mobility-mass spectrometry Chemical characterization of 15 biocrudes obtained from hydrothermal liquefaction of industrially cultivated wild micro algae Chemical characterization with different analytical techniques, a way to understand the process: Case of the paraffinic base oil production line Exploring complex mixtures by cyclic ion mobility high-resolution mass spectrometry – Application towards Petroleum. Simulation and modeling of Collision Cross Section for structural elucidation of heavy oil fraction by ion mobility-mass spectrometry: Using polyaromatic hydrocarbons compounds mixture as calibration standard Characterization of sulfoxides compounds in dimeric distribution of heavy oil fractions by positive-ion electrospray ionization FTICR mass spectrometry Structural analysis of Petroporphyrins from asphaltene by trapped ion mobility coupled with a Fourier transform ion cyclotron resonance mass spectrometer. Cyclic ion mobility spectrometry coupled to high-resolution time-of-flight mass spectrometry equipped with atmospheric solid analysis probe for the molecular characterization of combustion particulate matter. Structural study of analogues of Titan’s haze by trapped ion mobility coupled with a Fourier transform ion cyclotron mass spectrometer." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR051.
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L'évolution des réserves de pétrole implique l'utilisation en raffinerie de pétroles bruts non conventionnels, bien souvent plus lourds et donc difficiles à caractériser. Les produits pétroliers sont en effet des mélanges chimiques extrêmement complexes. La partie légère et volatile peut être analysée par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC/MS), permettant l'identification des composés par l'utilisation de mesures de masses précises et de modèles de fragmentation. Cependant ces techniques sont inadaptées à l'analyse des fractions lourdes. Dans la pratique, la caractérisation des mélanges les plus complexes implique l'utilisation de spectromètres de masse à ultra-haute résolution généralement par analyse directe sans séparation chromatographique. La technique de référence est aujourd’hui la spectrométrie de masse à transformée de Fourier par résonance cyclotronique des ions (FTICR). Grâce à une résolution supérieure à 106 et à une précision de mesure de masse inférieure à 0,1 ppm, cet instrument permet de séparer toutes les espèces présentes dans un produit pétrolier et d'attribuer à chaque valeur de m/z une composition élémentaire unique. Ceci permet d'obtenir très facilement des cartes moléculaires qui peuvent être présentées graphiquement en utilisant le diagramme de Kendrick, le diagramme de van Krevelen ou le nombre d'insaturations (DBE) en fonction du nombre de carbones. Ce travail de thèse a permis grâce à la caractérisation moléculaire de produits pétroliers (Vacuum Gas Oil, Pétroles Bruts, Matériel Interfacial, Asphaltènes et Bio-Oil…) d'aborder la complexité de leur traitement dans l’outil de raffinage. Des protocoles d'analyses des échantillons ont été développés, à l'aide de différentes sources d'ionisation à pression atmosphérique (ESI, APCI et APPI) ainsi que par désorption/ionisation laser (LDI) sur le spectromètre de masse FTICR 12T. Les informations sur le contenu isomérique des produits pétroliers ont ensuite été déterminées grâce à l'apport de la spectrométrie de mobilité ionique (IMS)The evolution of oil reserves requires the use in refineries of unconventional crude oils, which are often heavier and therefore difficult to characterize. Petroleum products are in fact extremely complex chemical mixtures. The light and volatile part can be analysed by gas chromatography coupled with mass spectrometry (GC/MS), allowing the identification of compounds by using precise mass measurements and fragmentation models. However, these techniques are inappropriate for the analysis of heavy fractions. In practice, the characterization of the most complex mixtures involves the use of ultra-high-resolution mass spectrometers generally by direct analysis without chromatographic separation. The reference technique today is Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR). With a resolution of more than 106 and a mass measurement accuracy of less than 0.1 ppm, this instrument can separate all the species present in a petroleum product and assign a unique elemental composition to each m/z value. This makes it very easy to obtain molecular maps that can be presented graphically using the Kendrick diagram, the van Krevelen diagram or the number of unsaturations (DBE) as a function of the number of carbons. This thesis work has allowed thanks to the molecular characterization of petroleum products (Vacuum Gas Oil, Crude Oil, Interfacial Material, Asphaltenes and Bio-Oil...) addressing the complexity of their treatment in the refining tool. Protocols for sample analysis have been developed, using different sources of ionization at atmospheric pressure (ESI, APCI and APPI) as well as laser desorption/ionization (LDI) on the FTICR 12T mass spectrometer. Information on the isomeric content of petroleum products was then determined using ion mobility spectrometry (IMS)
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Masschelein, C. A. "Etude photophysique de nouveaux complexes du ruthénium en solution et en matrice solide." Doctoral thesis, Universite Libre de Bruxelles, 1988. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213341.
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Hedibel, Mohammed. "Etude thermocinétique de la dissolution d'un métal solide dans une matrice métallique liquide." Nice, 1991. http://www.theses.fr/1991NICE4472.
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Par calorimetrie de reaction directe, le memoire analyse les mecanismes et la cinetique, d'une part de l'attaque d'un metal solide a par un element b en phase vapeur, d'autre part la dissolution de ce metal dans un alliage liquide a-b. Les thermogrammes obtenus sont deconvolues numeriquement et conduisent a la thermogenese reelle des phenomenes. La methode a ete appliquee au systeme ag-te en fonction de la temperature et de la concentration. Dans le cas des reactions solide-vapeur, la methode permet, sous certaines conditions, la determination des limites de phases du systeme a une temperature en une seule experience. Elle peut conduire a l'estimation du coefficient de diffusion des vapeurs b dans un gaz inerte (argon). En ce qui concerne la dissolution de l'argent dans l'alliage liquide ag-te, la formation transitoire d'une couche protectrice du compose ag#2te ralentissant la dissolution de l'argent et les cinetiques d'apparition et de dissolution de ce compose ont ete etudiees pour une gamme etendue de conditions experimentales. Enfin, le modele base sur les processus de diffusion a ete mis au point. Il decrit l'evolution des champs de concentration en fonction du temps, permet de prevoir les conditions d'existence de la couche intermediaire de compose et conduit ainsi aux lois cinetiques des phenomenes de dissolution
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Dury-Brun, Cécile. "Transferts de molécules volatiles entre une matrice solide alimentaire et un emballage souple." Dijon, 2006. http://www.theses.fr/2006DIJOS027.
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Cette étude porte sur le transfert de molécules volatiles (oxygène, vapeur d’eau et composés d’arôme essentiellement) dans et au travers d’emballages (thermoplastique et papiers traités), dans des conditions contrôlées de stockage (température et humidité relative); les composés d’arôme sont libérés par une matrice solide alimentaire (génoise). Différentes méthodes de détermination des paramètres de transfert des composés d’arôme dans les emballages sont comparées. Le transfert de molécules volatiles dans les emballages est essentiellement gouverné par leur diffusion, qui est diminuée suite à la compression des papiers. Le couchage des papiers modifie leur affinité pour les composés d’arôme. L’augmentation de température et d’humidité relative de stockage augmente les transferts et modifie les interactions entre composés d’arôme et papiers traités. Suite aux transferts de molécules volatiles dans les papiers traités, l’odeur et la texture de la génoise sont modifiées après stockageThis study deals with volatile molecules (oxygen, water vapour and especially aroma compounds) transfer into and through packaging (treated-papers and thermoplastic), in controlled storage conditions (temperature and relative humidity); aroma compounds are released by a solid food matrix (sponge cake). Different methods are compared between each others for the determination of the transfer parameters of aroma compounds through packaging. Volatile molecules transfer through packaging is essentially governed by their diffusion which decreases by compression of papers. Paper coating modifies their affinity for aroma compounds. The increase of storage temperature and relative humidity increases transfers and modify interactions between aroma compounds and treated-papers. Due to volatile molecules transfers through treated-papers, the odour and texture of the sponge cake are modified after storage
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Idrissa, Almoustapha. "Etude d'agrégats de molécules de benzène en matrice de cyclohexane solide par spectroscopie infrarouge de Fourier." Poitiers, 1995. http://www.theses.fr/1995POIT2305.
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L'objet de cette these est l'etude d'agregats de molecules de benzene formes en matrice de cyclohexane solide, par spectrometrie infrarouge. Dans les agregats moleculaires, a basse temperature, il y a decomposition des modes de vibrations internes de la molecule en plusieurs sous-niveaux, sous l'effet de l'interaction intermoleculaire, par un mecanisme de transfert resonnant de l'energie vibrationnelle (exciton de davydov). Notre etude consiste a observer l'evolution de la structure des bandes d'absorption infrarouge des agregats, lorsqu'ils evoluent de la molecule isolee vers le cristal de benzene. Nous avons suivi la variation du profil des bandes d'absorption de classe de symetrie a#2#u, e#1#u, b#1#u, et e#1#u situees respectivement a 672,6, 1482, 3057 et 3068 cm#-#1 au niveau de la molecule libre de benzene, en fonction de la concentration de benzene dans la matrice. Les resultats obtenus sont interpretes dans le concept de la theorie de l'exciton vibrationnel et de la theorie des groupes. Pour des concentrations de benzene tres faibles (0,2 a 0,5%), les spectres obtenus sont caracteristiques de molecules de benzene isolees en matrice. Pour les concentrations voisines de 1 et 2%, des molecules isolees, des dimeres et des agregats de faibles dimensions ont ete observes dans la matrice. A partir de 3%, nous avons obtenu des microcristaux (agregats ordonnes) de structure identique a celle du cristal de benzene. Ces resultats ont montre que la structure des agregats evoluent tres rapidement avec la concentration de benzene. L'ecart des niveaux d'energie du monomere et du dimere, a permis de determiner le parametre d'interaction resonnante le plus fort, de l'ordre de 2,63 cm#-#1. Le cyclohexane presente une transition de phase ordre-desordre a t#c = 186 k. Nous avons montre que cette transition de phase peut etre caracterisee par une etude en fonction de la temperature, de la structure excitonique des agregats ou du deplacement en frequence et de la largeur a mi-hauteur de la bande d'absorption de la molecule de benzene piegee en matrice
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Nouvian, Laurine. "Élaboration et caractérisation d'une nouvelle matrice céramique pour CMC par réaction solide-gaz activée et expansive." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0187.
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Parmi les différents procédés d’élaboration d’un composite à matrice céramique (CMC), peu d’entre eux permettent d’obtenir un matériau dont la densité dépasse 90%, hormis la Melt Infiltration (MI). Le but de cette thèse est donc d’élaborer une nouvelle matrice céramique pour obtenir un CMC avec une porosité résiduelle inférieure à 10%. En se basant sur le procédé présenté par Peter Greil en 1992, cette matrice est élaborée selon un procédé hybride combinant d’une part la voie liquide et d’autre part la voie solide. Ainsi, une charge réactive pulvérulente, composée d’un mélange de TiSi2 et de Ni, a été associée à une résine précéramique. Lors de sa nitruration, la poudre s’expanse et compense le retrait volumique de la résine. Par pyrolyse de la résine et nitruration de la poudre, sous diazote, une matrice type nitrure est formée. L’additif métallique ajouté, Ni, favorise la nitruration de la poudre qui, sans son ajout, demeure partiellement nitrurée : Du Si libre subsiste dans la matrice, et détériore les propriétés du matériau. Un certain nombre de paramètres influe sur cette réaction : la granulométrie de la poudre, la méthode de broyage, la teneur en nickel, les impuretés, la mise en forme ou encore la durée et la température du traitement thermique. L’ensemble de ces paramètres a été étudié afin d’élaborer la matrice souhaitée. Cette nouvelle matrice a ensuite été caractérisée afin d’étudier l’évolution de sa porosité, ainsi que son comportement physico-chimique tel que sa résistance à l’oxydation ou sa stabilité thermique. Enfin, la faisabilité d’un composite a été étudiée pour conclure ces travaux de rechercheAmong the various processes for producing a ceramic matrix composite (CMC), few of them make it possible to obtain a material whose density exceeds 90%, except for Melt Infiltration (MI). The aim of this thesis is to develop a new ceramic matrix to develop a CMC with a residual porosity of less than 10%. Based on the process presented by Peter Greil in 1992, this matrix is developed using a hybrid process combining both the liquid and the solid paths. Thus, a powdered reactive filler composed of a mixture of TiSi2 and Ni has been associated with a preceramic resin. During its nitridation, the powder expands and compensates for the volume shrinkage of the resin. By pyrolysis of the resin and nitridation of the powder, under nitrogen, a nitride type matrix is formed. The metal additive, Ni, promotes the nitridation of the powder which, without its addition, remains partially nitride: Free Si remains in the matrix, and deteriorates the properties of the material. Several parameters influence this reaction: the particle size of the powder, the grinding method, the nickel content, the impurities, the shaping or the duration and the temperature of the heat treatment. All these parameters have been studied in order to elaborate the desired matrix. This new matrix was then characterized in order to study the evolution of its porosity, as well as its physicochemical properties such as its resistance to oxidation or its thermal stability. Finally, the feasibility of a composite was studied to complete this work
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PANEPINTO, DEBORAH. "Analisi analitico sperimentale dei trattamenti termici tradizionali ed innovativi per diverse matrici solide." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2496976.
Full textAbstract:
The national and international situation for the definition of integrated systems for the treatment and the final destination of solid wastes presents, today, a significant affirmation of separate collection system aimed to the creation of processes and plants for the reuse and production of secondary materials.
Downstream of this, there is, anyway, an important flow of waste that is collected without differentiation; to this flux the rejects deriving from the recycle operations must necessarily be added, and for this resulting flux it is necessary to individuate suitable prospects for disposal. This obtained flow in comparison with the gross waste production is a large percentage; from the point of view of quality, it has a composition deprived of the fractions that more easily can be recovered (metal, glass, organic waste find an appropriate valorization after upstream pre - selection), and it can be considered as constituted of a dry combustible fraction, a wet organic fraction and a substantially inert mineral fraction.
In account of the composition and also of the ever increasing interest for the production of energy from non fossil sources, this fraction must be sent to an energetic valorization (by using direct combustion systems, in traditional incineration, or by using innovative systems of gasification); the purpose of this destination relies in the possibility, together with a convenient disposal, to simultaneously produce sustainable energy to be used in the individuated area.
On the basis of this general perspective the aim of this work is a careful analysis of the thermal treatment systems for municipal solid wastes, but also for other matrices such as, in particular, biomasses (chiefly wood biomasses) and sludges deriving from wastewater treatment plant, that can also be considered for thermal use. The study is aimed to the analysis both of conventional thermal treatments (direct combustion in incineration plant) and also innovative solutions (especially gasification plants). For this purpose, after a thorough analysis of the scientific literature that allowed the reconstruction of a solid theoretical and technological reference base, and also a careful analysis of the practical real scale implementation state of the art, the different technologies for thermal treatment have been were analyzed in detail, both from an analytical and from an experimental point of view.
From the point of view of the conventional, more diffused, thermal technologies we evaluated the performances and environmental effects of these treatments on the three different types of materials. In order to define plant conditions, effects on the quality of receiving context and environmental impact, an analysis of each realization has been performed from the operating scheme until to the environmental effects: the used tools were, in succession, the mass and energy balances to define the plant operating conditions, the tool of externalities and the application of different pollutant dispersion models (ISC3 Short Term and SPRAY) to establish air quality modifications.
For a correct mass balance definition, in some cases a deeper knowledge of the original treated material was required, and in these cases it has been necessary to perform laboratory tests (by using analysis instruments as the Mahler bomb calorimeter, the ionic spectrophotometer and more in general by using the instrument of titration).
A different approach was required to study innovative technologies, gasification in particular. In this case, in the lack of enough informations about the process parameters, we developed a predictive calculation model, that is based on the evaluation of the mass and energy balances and the chemical homogeneous gas phase equilibria able to regulate the development of the process. This model allows to estimate the quantitative and qualitative production of the syngas, and from this the energy yield of the process. We tested the model by considering a feed composed by MSW (municipal solid waste) and an RDF (refuse derived fuel) alimentation. We also evaluated the effects on results of different qualities of gasifying agent (air, air enriched with oxygen, air enriched with carbon dioxide and air enriched with steam).
On the basis of the calculated results and also taking into account the general informations about the more consolidated conventional technologies we have also conducted a comparison, from energetic, environmental and economic point of view, between traditional and innovative thermal treatments.
By taking also in account the real possibilities of implementation of these systems, in the final chapter we conducted a comparison among scenarios of waste management dedicated to residual wastes with and without a specific downstream separation stage that, with a mechanical separation, is able to produce three flows: a dry combustible flow, a wet organic flow and an inert flow, with different destinations.
On the basis of the so indicated general scheme of the thesis, in the following we report the most important aspects of the obtained results:
• through the reconstructed study of performances and a careful literature analysis, it was possible to arrive to a general and full bibliographic review concerning thermal treatments;
• from a point of view of the more conventional incineration processes:
o a preliminary and operative scheme has been defined as concerns the choice and the verification of the correct technology for thermal treatment of MSW;
o it has been constructed and assessed an evaluation procedure able to define the environmental compatibility of biomass and other plants;
o a laboratory system of definition of the characteristics of the treated waste in some cases has been considered as convenient and propositive (as for example the definition of the chlorine content in sewage sludge); this aspect can be considered as an important step in the definition of planning the plant scheme.
• from a point of view of the innovative processes (in particular gasification) we developed and verified a predictive calculation model for the gasification process;
• from a point of view of the comparison between traditional and innovative processes the main differences among the systems have been estimated by analyzed analytical laboratory tests and mass and energy balances;
• from the point of view of the comparison between completely thermal scenarios for waste management and scenarios where also MBT procedures are considered it was individuated a procedure for the evaluation and the comparison of these scenarios from the point of view of the environmental impact and also with the aim of the evaluation of the economic aspects.
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Ferrand, Alain. "Interfaces alumine-fer : relations entre l'énergie, la structure et les variables thermodynamiques température et potentiel chimique d'oxygène." Paris 11, 2001. http://www.theses.fr/2001PA112276.
Full textAbstract:
Des polycristaux d'oxydes mixtes (Al,Fe)2O3 avec différentes teneurs en fer obtenus par pressage uniaxial à chaud, ainsi que des oligocristaux préparés au four à image par solidification dirigée à partir de la fusion ont été exposés à une atmosphère suffisamment réductrice pour précipiter le fer métallique. Nous avons ainsi pu déterminer pour l'activité d'oxygène la plus faible, les plans denses d'alumine délimitant les précipités de fer métalliques, ainsi que les rapports de distances interfaciales caractérisant la morphologie d'équilibre. En équilibrant ces précipitants à une activité d'oxygène plus élevée, nous avons observé une modification de la morphologie d'équilibre, liée à la variation de l'activité d'oxygène. Cette évolution peut être décrite par un modèle d'adsorption de Gibbs aux interfaces entre métal et oxyde qui prédit l'évolution avec l'activité d'oxygène des concentrations d'excès des différents plans interfaciaux d'alumine, permettant ensuite d'évaluer la stabilisation de l'énergie interfaciale provenant des liaisons établies entre le fer métallique et l'alumine aux extrémités du domaine de coexistence. .Mixed oxides polycrystals (Al,Fe)2O3 with differents doping levels obtained by hot pressing, as well as oligocrystals elaborated by the floating-zone method in the image furnace have been exposed to sufficiently reducing atmosphere to precipitate metallic iron. Thus, we could determine for the lowest oxygen activity, the dense alumina planes delimiting metallic iron precipitates, as well as interfacial distance ratios characterizing the equilibrium shape. At higher oxygen activity, we observe a modification of the equilibrium shape, connected to the oxygen activity change. This evolution might be described by a model of Gibb's adsorption at metal-oxide interfaces, that predict the evolution with oxygen activity of the excess concentration of different interfacial alumina planes, alowing us to evaluate the stabilization of interfacial energy arriving from bonds established between metallic iron and alumina at the ends of the coexistence field. .
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Madru, Benjamin. "Développement d'un support d'extraction sélective à base d'aptamères : synthèse, caractérisation et application à des matrices complexes." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://pastel.archives-ouvertes.fr/pastel-00538840.
Full textAbstract:
L'analyse de composés à l'état de traces dans des échantillons complexes tels que les fluides biologiques, les matrices environnementales ou les denrées alimentaires nécessite une étape de purification avant analyse afin de limiter la présence d'effets de matrice. Les supports conventionnels d'extraction sur phase solide, bien qu'étant très efficaces pour préconcentrer l'échantillon, conduisent souvent à la co-extraction de composés interférents. Afin de pallier ce manque de sélectivité, des supports sélectifs fondés sur des mécanismes de reconnaissance moléculaire ont été développés. Les immunoadsorbants, reposants sur l'utilisation d'anticorps dirigés contre l'analyte et immobilisés sur un support solide, et les polymères à empreintes moléculaires qui possèdent des cavités spécifiques complémentaires d'une molécule empreinte, ont déjà démontré un fort potentiel pour l'extraction sélective de composés de matrices complexes. Un troisième type de support d'extraction sélective également fondé sur un mécanisme de reconnaissance moléculaire exploitant les propriétés des aptamères a été développé lors de cette étude. Les aptamères sont des oligonucléotides capables de fixer de manière spécifique une molécule avec une affinité comparable à celle des anticorps. Un aptamère sélectionné pour reconnaître la cocaïne a été choisi comme aptamère modèle pour cette étude de faisabilité. Différents supports d'immobilisation ont été évalués et les oligoadsorbants obtenus ont été caractérisés en termes de rétention spécifique et non spécifique, de taux de greffage, et de capacité. La sélectivité du support le plus performant en milieu pur a ensuite été évaluée en réalisant l'extraction de la cocaïne de plasma et de sang. L'analyse chromatographique des extraits obtenus a conduit à des chromatogrammes dépourvus de co-élutions, contrairement à ceux issus des traitements généralement employés, démontrant ainsi l'apport en purification de l'oligoextraction. Ce développement a ensuite été transposé avec succès à un autre aptamère, l'aptamère anti-ochratoxine A. L'oligoadsorbant obtenu s'est montré très rétentif, du fait de sa forte affinité, et a permis l'extraction sélective de l'ochratoxine A du vin. Les résultats obtenus sont très similaires à ceux obtenus avec un immunoadsorbant. De plus, les procédures d'extraction s'avèrent beaucoup plus simples à développer que pour les polymères à empreintes moléculaires.
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Badré, Sophie. "Étude de dérivés de Bodipy à l'état solide et en matrice polymère : vers la réalisation de nanocapteurs." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2007. http://tel.archives-ouvertes.fr/tel-00199576.
Full textAbstract:
La fluorescence d'assemblées de dérivés de Bodipy a été étudiée afin de réaliser des nanocapteurs. Les nanoobjets envisagés sont soit des nanocristaux soit des particules de polystyrène en suspension dans l'eau, i.e. des nanolatex. Dans un premier temps, des molécules encombrées ont été synthétisées afin de limiter les interactions entre fluorophores à l'état solide. Les résultats obtenus à l'état amorphe montrent que cette stratégie est prometteuse. Les propriétés de fluorescence de cryptobodipy ont aussi été étudiées. L'étude des structures cristallographiques de certaines de ces molécules a permis de mieux comprendre la fluorescence à l'état solide des Bodipy. Enfin, pour l'iodophénylbodipy, la formation d'agrégats de type J dans le solide a été démontrée et il est possible de préparer des nanoparticules fluorescentes à partir de cette molécule. La fluorescence de certains Bodipy en matrice polymère a aussi été étudiée. La fluorescence de films de PMMA contenant du PM597 a pu être modulée par transfert d'¤énergie vers une molécule photochrome. D'¤autre part, la fluorescence de nanolatex contenant du trimésitylbodipy à été éteinte de manière très efficace par du bleu de cibacron, ce qui montre l'intérêt de développer des nanocapteurs à partir de ces particules.
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Badré, Sophie. "Etude de dérivés de Bodipy à l'état solide et en matrice polymère: vers la réalisation de nanocapteurs." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2007. http://tel.archives-ouvertes.fr/tel-00180135.
Full textAbstract:
La fluorescence d'assemblées de dérivés de Bodipy a été étudiée afin de réaliser des nanocapteurs. Les nanoobjets envisagés sont soit des nanocristaux soit des particules de polystyrène en suspension dans l'eau, i.e. des nanolatex.
Dans un premier temps, des molécules encombrées ont été synthétisées afin de limiter les interactions entre fluorophores à l'état solide. Les résultats obtenus à l'état amorphe
montrent que cette stratégie est prometteuse. Les propriétés de fluorescence de cryptobodipy ont aussi été étudiées. L'étude des structures cristallographiques de certaines de ces
molécules a permis de mieux comprendre la fluorescence à l'état solide des Bodipy. Enfin, pour l'iodophénylbodipy, la formation d'agrégats de type J dans le solide a
été démontrée et il est possible de préparer des nanoparticules fluorescentes à partir de cette molécule.
La fluorescence de certains Bodipy en matrice polymère a aussi été étudiée. La fluorescence de films de PMMA contenant du PM597 a pu être modulée par transfert d'énergie
vers une molécule photochrome. D'autre part, la fluorescence de nanolatex contenant du trimésitylbodipy a été éteinte de manière très efficace par du bleu de cibacron, ce qui montre
l'intérêt de développer des nanocapteurs à partir de ces particules.
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Wang, Ming Hua. "Oxidative stability of whey protein-coated milkfat droplets encapsulated in wall matrices consisting of non-fat milk solids or of carbohydrates /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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