No description available.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: In reverse iodine transfer polymerisation (RITP), chain transfer agents (CTAs) are generated in situ from the reaction between 2,2’-azobis(isobutyronitrile) (AIBN) and molecular iodine. This stage of RITP is the inhibition period, which ends when all iodine has been consumed. The evolution of CTAs was studied for the polymerisation reactions of n-butyl acrylate and styrene respectively. RITP of n-butyl acrylate was performed at 70 °C. In situ 1H nuclear magnetic resonance (NMR) experiments were carried out to study the evolution of CTAs during the inhibition period of n-butyl acrylate polymerisation and the structures A-I and A-Mn-I (where A represents the moiety originating from AIBN, M represents the monomer unit and n is the mean number degree of polymerisation) were observed. A polymer with the general structure A-Mm-I is formed. The molecular weight of poly(n-butyl acrylate) (PnBA) was evaluated with size exclusion chromatography (SEC) and NMR. Structural analysis of PnBA was done using NMR spectroscopy and matrix-assisted laser desorption/ionisation time-of-flight (MALDI-ToF) mass spectrometry. Similar conditions to those used for n-butyl acrylate polymerisation were used for RITP of styrene. The evolution of CTAs during the inhibition period of styrene polymerisation was studied using in situ 1H NMR. The inhibition period of styrene polymerised by RITP was much shorter than expected. This is due the consumption of iodine in the reaction between styrene and iodine which reversibly forms 1,2-diiodo-ethyl benzene. The CTAs A-I and A-Mn-I are formed, as well as 1-phenylethyl iodide (1-PEI). The molecular weight of polystyrene (PS) was determined using SEC and NMR and the functionality was evaluated using 1H NMR. The structure of PS was confirmed with 1H NMR and MALDI-ToF mass spectrometry. By increasing the temperature of the reaction, the inhibition period can be shortened. Both polymerisation systems retain control over molecular weight with an increase in temperature, however, n-butyl acrylate is limited due to the possible formation of mid-chain radicals. The formation of an A–Mm–A population (direct combination of the initiator and styrene) in RITP of styrene results in more initiator being consumed than for n-butyl acrylate, despite limited conversion of styrene to polymer. / AFRIKAANSE OPSOMMING: In omgekeerde-jodium-oordrag polimerisasie, is die kettingoordragagente gegenereer in situ van die reaksie tussen 2,2’-azobis(isobutironitriel) (AIBN) en molekulêre jodium. Hierdie fase van RITP is die inhibisie tydperk wat eindig wanneer alle jodium verbruik is. Die evolusie van kettingoordragagente is vir die polimerisasiereaksies van butielakrilaat en stireen onderskeidelik bestudeer. Omgekeerde-jodium-oordrag polimerisasie van butielakrilaat was uitgevoer by 70 °C. In situ 1H kernmagnetieseresonans (KMR) eksperimente is uitgevoer om die evolusie van die kettingoordragagente te bestudeer tydens die inhibisie van butielakrilaat polymerisasie en die strukture A-I en A-Mn-I (waar A die gedeelte voorstel wat afkomstig is van AIBN, M die monomeer-eenheid en n die gemiddelde aantal polymerisasiegraad verteenwoordig) is ge-identifiseer. 'n Polimeer met die algemene struktuur A-Mm-I is gevorm. Die molekulêre gewig van poli(butielakrilaat) (PnBA) was geëvalueer deur grootte-uitsluitings chromatografie en KMR spektroskopie. Strukturele ontleding van PnBA is gedoen deur die KMR spektroskopie en matriks ge-assisteerde laser desorpsie/ionisasie tyd-van-vlug massaspektroskopie. Soortgelyke kondisies as dié wat gebruik word vir butielakrilaat polymerisasie, is gebruik vir omgekeerde-jodium-oordrag polimerisasie van stireen. Die evolusie van die ketting oordrag agente gedurende die inhibisie periode van stireen polymerisasie is deur in situ 1H KMR bestudeer en die inhibisie periode is baie korter as verwag. Dit is as gevolg van die opname van jodium in die reaksie tussen stireen en jodium wat omkeerbare stireen-di-jodied tot gevolg hê. Die ketting oordrag agente A-I en A-Mn-I is gevorm, sowel as 1-feniel-etiel jodied. Die molekulêre massa van polistireen (PS) is bepaal met behulp van grootte-uitsluitings chromatografie en KMR spektroskopie en die funksioneering is geëvalueer met behulp van 1H KMR. Die struktuur van PS is bevestig deur 1H KMR en matriks ge-assisteerde laser desorpsie/ionisasie tyd-vanvlug massaspektroskopie. Deur die verhoging van die temperatuur van die reaksie, kan die inhibisie periode verkort word. Beide polimerisasie sisteme behou beheer oor die molekulêre massa met 'n toename in temperatuur, alhoewel butielakrilaat beperk word as gevolg van die moontlike vorming van middel kettingradikale. Die vorming van die A-Mm-A spesie (direkte kombinering van AIBN en stireen) in omgekeerdejodium- oordrag polimerisasie van stireen veroorsaak dat meer AIBN verbruik word as butielakrilaat, ten spyte van die beperkte omskakeling van stireen tot polimeer.

BAKGRUND: Prostatacancer (PCa) är den vanligaste cancerformen bland män i Sverige. Efter kirurgisk behandling, radikal prostatektomi (RP), drabbas många av urininkontinens och sexuella besvär. Studier på kvinnor visar att urininkontinens påverkar sexuell lust men det finns få liknande studier bland män. SYFTE: Syftet med studien är att jämföra självskattad sexuell lust bland män med och utan inkontinens, ett år efter RP. METOD: Denna kvantitativa tvärsnittstudie utgår från enkätmaterial insamlat i en pågående prospektiv studie. Data insamlat bland 1751 män, ett år efter RP, har analyserats och jämförts mellan två grupper (fall-kontrollstudie). RESULTAT: Resultatet visar att män med urininkontinens skattar lägre sexuell lust, ett år efter RP, än män utan urininkontinens samt att de i högre grad beskriver tanken på ett fortsatt liv med sina sexualproblem med negativa begrepp. KONKLUSION: Män som genomgått RP, och i synnerhet de som har urininkontinens, har nedsättningar i sexuallivet. Sjuksköterskan bör uppmärksamma och ge tid till samtal om påverkan på sexuallivet efter RP, med både patient och partner. Ökad kunskap inom området bidrar till ökad förståelse, och behövs för att sjuksköterskor ska kunna hjälpa dessa patienter. Nedsatt sexuell lust hos män är ett outforskat område och vidare forskning behövs. / BACKGROUND: Prostate cancer (PCa) is the most common form of cancer among Swedish men. Urinary incontinence and sexual dysfunction are two side effects that many men experience after surgery, radical prostatectomy (RP). Previous studies show that urinary incontinence has negative effects on women’s sexual desire. Few similar studies concern men. AIM: The aim of the study is to compare self-reported sexual desire among men with and without urinary incontinence, one year post-surgical treatment (RP). METHOD: This quantitative, cross-sectional study is based on a self-reported survey from an ongoing prospective study. Data collected from 1751 men, one year post-treatment, have been analyzed and compared between two groups (case-control study). RESULT: The result shows that men with urinary incontinence after RP have less sexual desire than men without urinary incontinence. These men are also less satisfied with the idea of spending the rest of their lives with their sexual problems. CONCLUSION: Men that have undergone RP, especially the ones who have urinary incontinence, experience sexual dysfunction. Nurses need to acknowledge and initiate dialogues with patients and their partners about effects on sexual life after RP. Research concerning men’s sexual desire will help nurses’ knowledge and ability to discuss sexual problems. More studies about men’s reduced sexual desire are necessary.

Thesis (PhD (Civil Engineering))--Stellenbosch University, 2008. / Radical, far-beyond-the-norm innovation engages unknown developmental frontiers outside the familiar fields of standardised practice, requiring new and broad perspectives. This implies significant uncertainty during problem solution – the more radical, the greater the uncertainty. No systematic procedures for managing radical innovation exist. Research managers agree that traditional, standardised innovation approaches do not provide sufficient support for managers to cope with the degree of functional uncertainty typical of radical innovations. An efficient approach for delimiting and describing its uncertainties and managing the development process during the radical innovation process is sought. This thesis synthesizes a methodology for radical innovation from Systems Engineering and Management of Technology theory. Its application in a case study illustrates how it facilitates efficient strategic decision-making during radical innovation. Systems Engineering, by its comprehensive perspective, provides a valuable non-intuitive framework from which required radical innovation functionalities and uncertainties are identified, delimited, characterised and developed. Management of Technology concerns the core theory of technology; its perspective on technology provides the radical innovation process with a means of characterising and delimiting status, potential and uncertainty of functional, technological elements in the system. The resulting Radical Innovation Methodology is verified through application to an emerging renewable energy concept, the Solar Chimney Power Plant, which responds to a demand for innovation aimed at sustainable energy generation. The radically tall chimney structure required by the plant, proposed to stand 1,500 meter tall, serves as a fitting case for illustrating the methodology. Addressing and solving of challenges and uncertainties related to the radically tall structure and associated costs are required toward competence of this concept in a global energy market.

Thesis (PhD)--University of Stellenbosch, 2011. / Please refer to full text to view abstract.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study describes the synthesis and self-assembly of hetero-arm molecular brushes (hetero-arm MBs). These MBs consist of two polymeric side chains (SCs) of different natures, alternatingly distributed along the main chain (backbone). Two different types of hetero-arm MBs were prepared: first, alternating amphiphlic hetero-arm MBs (AMBs), and second, alternating hetero-arm MBs (AHMBs). Hetero-arm AMBs were synthesized via two strategies: (I) via a combination of “grafting through” and “grafting onto”, and (II) via “grafting through”. In approach (I), poly[vinyl benzyl (polyethylene glycol)-alt-N-alkyl-maleimide)] (poly[VB-(PEG12)-alt-N-(CnH2n+1)-MI]) was prepared via radical copolymerization of vinyl benzyl-terminated polyethylene glycol (VB-PEG12) with maleic anhydride (MAnh) (grafting through), which produces graft copolymers with PEG SCs and reactive succinic anhydride repeat units alternatingly distributed along the backbone. These graft copolymers were then modified by nucleophilic substitution (imidization) with alkyl amines (CnH2n+1-NH2) on the succinic anhydride residues (grafting onto). Three different primary amines possessing different alkyl chain lengths (n = 4, 12 and 16) were used in the modification process. In this way, hetero-arm AMBs with different hydrophilic to hydrophobic ratios were obtained. In approach (II), similar hetero-arm AMBs were prepared in a one-step grafting through approach. In this case, poly[VB-(PEG17)-alt-N-(CnH2n+1)-MI] (n = 10, 16 and 20) was prepared via radical copolymerization of VB-PEG17 with N-dodecylmaleimide, N-hexadecylmaleimide and N-icosylmaleimide. Following the synthesis step, self-assembly of these hetero-arm AMBs in arm-selective solvents was investigated in relation to the alkyl chain length. The morphology of the obtained assemblies was characterized by Field Emission gun-Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM) and Fluorescence Microscopy (a fluorescent dye was encapsulated). Cylindrical-like aggregates, length 10 μm and diameter ~ 250 nm, were obtained upon hetero-arm AMBs self-assembly. The second type of hetero-arm MBs was hetero-arm AHMBs, in which the SCs consist of PEG and poly(N,N-dimethylamino-ethyl methacrylate) (PDMAEMA). These hetero-arm AHMBs were prepared via a combination of grafting through and grafting from approaches. In this case, poly[vinyl benzyl-(polyethylene glycol)-alt-N-(poly(N,N-dimethylamino-ethyl methacrylate) maleimide] (poly[VB-(PEG17)-alt-N-(PDMAEMA)-MI) was prepared in the following steps: (1) alternating poly[vinyl benzyl-(polyethylene glycol)-alt-N-(4-hydroxyphenyl) maleimide] (poly[VB-(PEG17)-alt-N-(HPh)-MI]) was synthesized via radical copolymerization of VB-PEG17 with N-(4-hydroxyphenyl) maleimide (N-HPhMI). (grafting through), (2) the hydroxyl sites were esterified with 2-bromoisobutyryl bromide to afford poly [vinyl benzyl-(polyethylene glycol)-alt-N-(4-(2-bromobutyryloxy)phenyl) maleimide] (poly[VB-(PEG17)-alt-N-(BrPh)-MI]) (macroinitiator) and (3) an atom transfer radical polymerization (ATRP) reaction of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) was initiated from the obtained macroinitiator. This approach afforded poly[VB-(PEG17)-alt-N-(PDMAEMA)-MI] hetero-arm AHMBs with two water soluble SCs; however, one is water soluble at all pHs and temperatures (i.e. PEG), while the other is a pH- and temperature-sensitive polymer (i.e. PDMAEMA). Initial attempts were made to fabricate cylindrical organo/silica hybrid materials based on these AMHBs as the organic template and tetra-ethylorthosilicate as the silica precursor. Preliminary results indicate the formation of silica nano-wires, ~ 8 μm in length and ~45 nm in diameter. The self-assembly behavior of these AHMBs in water at a temperature above the lower critical solution temperature of PDMAEMA (> 55 °C) was also investigated. Fibril morphology (~ 30 nm in diameter) was observed. This study addresses initial attempts to fabricate organic/inorganic hybrid materials with controlled size and morphologies via densely grafted hetero-arm molecular brushes. / AFRIKAANSE OPSOMMING: Hierdie studie beskryf die sintese en selfsamestelling van prototipe molekulêre borsels (prototipe MBs). Hierdie MBs bestaan uit twee polimeriese sykettings (SKs) van verskillende aard wat afwisselend langs die hoofketting (ruggraat) voorkom. Twee verskillende tipes van die prototipe MBs is gesintetiseer: eerstens, afwisselende amfifiliese prototipe MBs (AMBs), en tweedens, afwisselende hetero-arm prototipe MBs (AHMBs). Prototipe AMBs is gesintetiseer d.m.v. twee strategieë: (I) deur 'n kombinasie van „enting deur‟ en „enting aan‟ benaderings, en (II) deur middel van „n „enting deur‟ benadering. In benadering (I) is poli[vinielbensiel(poliëtileenglikol)-alt-N-alkiel-maleïenamied)] (poli[VB-(PEG12)-alt-N-(CnH2n+1)-MI]) gesintetiseer deur radikaalkopolimerisasie van vinielbensiel-beëindigde-poliëtileenglikol (VB-PEG12) met maleïenanhidried („enting deur‟) wat entkopolimere produseer met PEG SKs en reaktiewe suksienanhidried herhaaleenhede wat afwisselend langs die ruggraat versprei is. Daarna is die entkopolimere gewysig d.m.v. nukleofiliese substitusie (imiedisering) met alkielamiene (CnH2n+1-NH2) op die oorblywende suksienanhidried („enting op‟). Drie verskillende primêre amiene met verskillende alkielkettinglengtes (n = 4, 12 en 16) is gebruik vir die wysigingsproses. So is prototipe AMBs met verskillende hidrofiliese tot hidrofobiese verhoudings verkry. In benadering (II) is soortgelyke prototipe AMBs gesintetiseer in 'n een-stap „enting deur‟ benadering. In hierdie geval is poli[VB-(PEG17)-alt-N-(CnH2n+1)-MI] (n = 10, 16 en 20) gesintetiseer d.m.v. radikaalkopolimerisasie van VB-PEG17 met N-dodesiel maleïenamied, N-heksadesiel maleïenamied en N-ikosiel maleïenamied. Na afloop van die sintese stap is die selfsamestelling van hierdie prototipe AMBs in spesifieke oplosmiddels in verhouding tot die alkielkettinglengtes ondersoek. Die morfologie van die versamelings is gekarakteriseer deur veld-emissie-geweer-(Eng: field emission gun-)-skandeerelektronmikroskopie (FE-SEM), transmissie-elektronmikroskopie (TEM) en fluoresserende mikroskopie („n fluoresserende kleurstof is ingesluit). Silinderagtige versamelings (lengtes ~10 μm en deursnee ~250 nm) is deur die selfsamestelling van prototipe AMBs verkry. Die tweede soort prototipe MBs is prototipe AHMB, waarin die SKs uit PEG en poli(N,N-dimetielaminoetiel metakrilaat) (PDMAEMA) bestaan. Hierdie prototipe AHMBs is d.m.v. 'n kombinasie van „enting deur‟ en „enting van‟ benaderings gesintetiseer. In hierdie geval is poli[vinielbensiel-(poliëtileenglikol)-alt-N-(poli(N,N-dimetielaminoetiel metakrilaat) maleïenamied] (poli[VB-(PEG17)-alt-N-(PDMAEMA)-MI) gesintetiseer deur van die volgende stappe gebruik te maak: (1) sintese van afwisselende poli[vinielbensiel-(poliëtileenglikol)-alt-N-(4-hidroksifeniel) maleïenamied] (poli[VB-(PEG17)-alt-N-(HPh) -MI) deur midel van radikaalkopolimerisasie van VB-PEG17 met N-(4-hidroksifeniel) maleïenamied (N-HPhMI) („enting deur‟), (2) esterifikasie van die hidroksielgroepe met 2-bromoisobutiriel bromied om poli[vinielbensiel-(poliëtileenglikol)-alt-N-(4-(2-bromobutirieloksi) feniel) maleïenamied] (poli[VB-(PEG17)-alt-N-(BrPh)-MI]) (makro-afsetter) te berei, en (3) die atoomoordrag-radikaalpolimerisasie reaksie van 2-(N,N-dimetielamino)etiel metakrilaat (DMAEMA) wat begin is vanaf die gevormde makro-afsetter. Hierdie benadering gee poli[VB-(PEG17)-alt-N-(PDMAEMA)-MI] prototipe AHMBs met twee wateroplosbare SKs, waarvan een wateroplosbaar is by alle pHs en temperature (d.w.s. PEG), terwyl die ander tipe SK „n pH- en temperatuur-sensitiewe polimeer is (d.w.s. PDMAEMA). Aanvanklike pogings is aangewend om silindriese organo/silika hibriedmateriale te sintetiseer, gebaseer op hierdie AHMBs as die organiese segment en tetraëtielortosilikaat as die silika voorloper. Die voorlopige resultate dui op die vorming van silikananodrade, lengte ~8 μm en deursnit ~45 nm. Die selfsamestellingsgedrag van hierdie AHMBs is ook in water ondersoek by 'n temperatuur hoër as die laer kritieke oplossingstemperatuur van PDMAEMA (> 55 °C). „n Draadagtige morfologie (deursnit ~30 nm) is waargeneem. Hierdie studie beskryf aanvanklike pogings om organiese–anorganiese hibriedmateriale met beheerde groottes en morfologieë via dig-geënte hetero-arm molekulêre borsels te vervaardig.

This thesis addressed the problem of recognizing 3-D objects, using shape information extracted from range images, and parameterized volumetric models. The domains of the geometric shapes explored is that of complex curved objects with articulated parts, and a great deal of similarity between some of the parts. These objects are exemplified by animal shapes, however the general characteristics and complexity of these shapes are present in a wide range of other natural and man-made objects. In model-based object recognition three main issues constrain the design of a complete solution: representation, feature extraction, and interpretation. this thesis develops an integrated approach that addresses these three issues in the context of the above mentioned domain of objects. For representation I propose a composite description using globally deformable superquadratics and a set of volumetric primitives called geons: this description is shown to have representational and discriminative properties suitable for recognition. Feature extraction comprises a segmentation process which develops a method to extract a parts-based description of the objects as assemblies of defoemable superquadratics. Discontinuity points detected from the images are linked using 'active contour' minimization technique, and deformable superquadratic models are fitted to the resulting regions afterwards. Interpretation is split into three components: classification of parts, matching, and pose estimation. A Radical Basis Function [RBF] classifier algoritm is presented in order to classify the superquadratics shapes derived from the segmentation into one of twelve geon classes. The matching component is decomposed into two stages: first, an indexing scheme which makes effective use of the output of the [RBF] classifier in order to direct the search to the models which contain the parts identified. this makes the search more efficient, and with a model library that is organised in a meaningful and robust way, permits growth without compromising performance. Second, a method is proposed where the hypotheses picked from the index are searched using an Interpretation Tree algorithm combined with a quality measure to evaluate the bindings and the final valid hypotheses based on Possibility Theory, or Theory of Fuzzy Sets. The valid hypotheses ranked by the matching process are then passed to the pose estimation module. This module uses a Kalman Filter technique that includes the constraints on the articulations as perfect measurements, and as such provides a robust and generic way to estimate pose in object domains such as the one approached here. These techniques are then combined to produce an integrated approach to the object recognition task. The thesis develops such an integrated approach, and evaluates its perfomance inthe sample domain. Future extensions of each technique and the overall integration strategy are discussed.

<p>   Contamination of surface and ground water from industrial wastes and anthropogenic activities represents one of the greatest challenges to the sustainable development of human society. Heterogeneous photocatalysis, a kind of advanced oxidation process characterized by the production of highly oxidative hydroxyl radicals, is a relatively novel subject with tremendous potential in water treatment applications.</p><p>    The purpose of this research was first to develop feasible hydroxyl radical detection methods, which can be used to evaluate efficiency of photocatalytic process, and second to prepare immobilized TiO2 films with high photocatalytic activities by the sol gel method.</p><p>    The feasibility of Indigo carmine and phthalic hydrazide as OH-radical probes was investigated. The organic dye Indigo carmine absorbs visual light strongly at 610 nm and its destruction can be monitored conveniently in a spectrophotometer. Results showed that both ^·OH and HO₂^·can bleach Indigo carmine, and the bleaching yield of ^·OH was pH independent. The photocatalytic dye bleaching in black light UV illuminated Degussa P25 TiO2 aerated suspensions was then investigated. A strong pH dependency of the bleaching yield was found.  This implies that the quantum yield of OH radical at pH 3 is one fourth compared to that at pH 10. The reaction of the OH radical with phthalic hydrazide will form strongly chemiluminescent 3-hydroxyphthalic hydrazide. Using the more specific phthalic hydrazide as OH radical probe, an even stronger pH dependent quantum yield of OH radical was found. At pH 10 the quantum yield reached the same magnitude as that obtained by using Indigo carmine, whereas the quantum yields at acidic pH were close to zero. However it was found that the addition of phosphate and fluoride anions can substantially enhance the OH radical yield at acidic pH by blocking the adsorption of phthalic hydrazide onto the TiO2 surfaces. Hence the adsorption of phthalic hydrazide to TiO2 is an important factor to consider when this method is used. <em></em></p><p>    Photocatalytic TiO2 films coated on metal plates were prepared by a sol gel method using titanium isopropoxide as TiO2 precursor and isopropanol as solvent. The photocatalytic activity of the obtained films was evaluated by bleaching of indigo carmine at pH 9 under black light UV irradiation. The effect of the molar ratio of isopropanol, water and hydrochloric acid to titanium isopropoxide was studied. It was also shown that the activities of TiO2 films are considerably influenced by calcination temperature, coating cycles and the supporting materials.</p> / <p>    Förorening av yt- och grundvatten från industrier och humana aktiviteter utgör en av de största utmaningarna för en hållbar utveckling av det mänskliga samhället. Heterogen fotokatalys, en slags avancerad oxidations process som kännetecknas av att starkt oxidativa hydroxylradikaler produceras, är en relativt ny teknik med stor potential för vattenrening.</p><p>    Ett syfte med detta licentiatarbete var först att utveckla och genomföra olika metoder för att detektera bildningen av hydroxylradikaler såväl i laboratoriet som i tekniska miljöer. Det andra syftet med arbetet var att syntetisera immobiliserade TiO2 filmer med hög fotokatalytisk effektivitet med en sol-gel metod.</p><p>    Möjligheten att använda indigokarmin och ftalhydrazid som OH-radikalprob undersöktes. Det organiska färgämnet indigokarmin absorberar synligt ljus starkt vid 610 nm vilket gör att dess nedbrytning lätt kan följas i en spektrofotometer. Resultaten av gammaradiolys visade att båda ^•OH och HO₂^• kan bleka indigokarmin och att den blekning som härrör från ^•OH var oberoende av pH. Fotokatalytisk blekning av indigokarmin med blacklight UV bestrålning av  Degussa P25 TiO2 suspensioner undersöktes sedan. Ett starkt pH-beroende av blekningsutbytet erhölls vilket tolkas som att kvantutbytet av OH-radikaler vid pH 3 är en fjärdedel jämfört med det vid pH 10.</p><p>    När ftalhydrazid reagerar med OH-radikaler bildas starkt kemiluminiscent 3-hydroxy-ftalhydrazid. Med denna  specifika OH-radikalprob, erhölls ett ännu starkare pH beroende. Vid pH 10 var kvantutbytet i paritet med det som erhölls med indigokarmin, medan kvantutbytet vid lågt pH var nära noll. Tillsats av fosfat-  och fluoridjoner visade sig avsevärt öka OH-radikalutbytet vid lågt pH-värde genom att blockera adsorption av ftalhydrazid på TiO2 ytorna. Adsorptionen av ftalhydrazid på TiO2 är således en viktig faktor när denna metod används.</p><p>    Fotokatalytiskt verksamma TiO2-filmer på metallplattor framställdes med sol-gel metoden med titan-isopropoxide som TiO2-prekursor och isopropanol som lösningsmedel. Den fotokatalytiska aktiviteten av TiO2-belagda plattor utvärderades genom blekning av indigokarmin vid pH 9 under blacklight UV-bestrålning. Effekten av olika proportioner mellan isopropanol, vatten och saltsyra till titan isopropoxide undersöktes. Det visade sig att denfotokatalytiska aktiviteten av TiO2-plattorna i hög grad påverkades av kalcineringstemperatur, beläggningscykler och materialet i plattorna.</p>

L'installation de décharges sanitaires représente la seule méthode de stockage des déchets ménagers solides dans plusieurs pays. Les lixiviats générés à partir de ces décharges présentent une grande toxicité aigüe et chronique. Lorsqu'ils ne sont pas traités, ces lixiviats peuvent pénétrer dans la nappe phréatique ou contaminer les eaux de surface et donc contribuer à la pollution des eaux. Divers procédés biologiques ont été appliqués au traitement des lixiviats de décharge. Cependant, ces procédés sont relativement inefficaces pour le traitement des lixiviats à cause de la présence de composés bioréfractaires. D'autre part, les procédés d'oxydation avancée représentent une excellente alternative pour le traitement des eaux polluées par les polluants toxiques et/ou persistants (bioréfractaires). Dans ce travail, quelques procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués au traitement de deux molécules modèles appartenant chacune à une famille de polluants présents dans la matrice du lixiviat tunisien de la décharge contrôlée de Jebel Chakir (identifiée dans ce travail), à savoir, l'anhydride phtalique et le 8-hydroxyquinoléine sulfate. Pour ces deux molécules, une étude de la dégradation et la minéralisation a été réalisée en optimisant les paramètres expérimentaux. L'étude cinétique montre que la dégradation oxydative des deux polluants étudiés suit une cinétique de réaction du pseudo-premier ordre, avec des temps de dégradation assez courts. Par exemple, avec une anode de Pt, l'oxydation complète de l'anhydride phtalique a été achevée en moins de 15 min sous un courant appliqué de 2,88 mA cm-2. L'identification des intermédiaires aromatiques et carboxyliques à courte chaîne carbonée a permis de proposer un mécanisme de dégradation de l'anhydride phtalique par les radicaux hydroxyles. Les valeurs des constantes de vitesse des réactions entre les *OH, et les deux polluants et leurs intermédiaires ont été déterminés par la technique de cinétique de compétition à l'aide d'un composé de référence; l'acide 4-hydroxybenzoique. Le suivi de la toxicité lors du traitement de la solution de 8-HQS par la méthode Microtox®, (une méthode basée sur la mesure de l'inhibition de la luminescence des bactéries marines Vibrio fischeri) a montré la formation des intermédiaires plus toxiques que les molécules mères. Une comparaison des procédés d'oxydation avancée appliqués a été réalisée pour chacun des polluants. Enfin, différents procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués à la dépollution du lixiviat tunisien de Jebel Chakir. Une étude comparative a été réalisée afin d'évaluer le coût des procédés. L'ensemble des résultats obtenus confirme l'efficacité du procédé électro-Fenton pour la dépollution des lixiviats.

Ces travaux mettent en valeur les réactions multicomposants a base d'isonitriles dans différentes applications autour des réactions d'Ugi-Smiles et de Nef pour la synthèse de systèmes hétérocycliques complexes. Nous avons démontré la possibilité d'utiliser des 4-hydroxypyridine et pyrimidines dans des couplages Ugi-Smiles. Ces réactions ont été appliquées à la préparation d'analogues d'antipaludéens. Diverses applications radicalaires ont été explorées sur des adduits de Ugi et Ugi-Smiles ( chimie des xanthates, couplages oxydatifs d'indoles). Nous avons par ailleurs exploré la chimie des dihalogénoisonitriles dans différentes synthèses hétérocycliques.