• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 1
  • 1
  • Tagged with
  • 11
  • 6
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The determination of boron using 11B(p, α)8Be nuclear reaction

Mabuda, Azwihangwisi Iren January 2008 (has links)
>Magister Scientiae - MSc / Determination of trace quantities of boron is required in various studies of materials and in geology. Using 11B(p, α)8Be nuclear reaction with focused proton beam of 670 keV energy is one of the few microanalytical techniques capable of achieving detection limits in the 5-10 ppm range. The set-up for the determination of boron with high sensitivity was developed at iThemba LABS nuclear microprobe (NMP) facility by using a PIN photodiodes detector. The trace elements such as boron and lithium were analyzed using the nuclear reaction analysis (NRA) method. This project aims at performing microanalysis of boron by NRA method and reaching the developmental phase in which routine, non-destructive boron analyses would be possible at detection limits below 5 ppm. A 228Th source was used for energy calibration of the detector. Five set of standards and unknown samples with a wide range of boron concentrations were analyzed in order to demonstrate the effectiveness of the 11B(p, α)8Be reaction by NRA technique. The standards were used to calibrate the boron yield with respect to their concentration in order to determine the boron concentration of the unknown specimen from the calibrated curve. The determination of the detection limit was also addressed. The concentrations of boron from Mts+Tu 950 glass samples were ranging between 0.17-1.05 wt % and the detection limit of 8.6 ppm for the minimum counts of 100 for 1μC accumulated charge was obtained.
2

Measuring the 7Li(a ; g)11B reaction rate at temperatures relevant for the n-process / Mesure du taux de réaction de 7Li(a ; g)11B aux températures pertinentes pour le n-process

Gilardy, Gwenaelle 18 December 2018 (has links)
L’étude des réaction (a,g) d’intérêt astrophysique est vaste. Ces réactions ont un rôle important dans la phase de fusion d’hélium des étoiles, dans la nucléosynthèse au moment du big bang ainsi que dans une grande partie des scénarios d'explosions stellaires. L’étude des réactions (a,g) impliquant des faisceaux stables peut être réalisée de diverse façon. Je me suis concentrée sur deux d'entre elles. La première est l’étude en cinématique directe en détectant les rayons gamma produits. C'est ce que j'ai fait durant ma thèse pour mesurer la section efficace de 7Li(a,g)11B. Cette réaction a été étudiée au cours des années pour différentes raisons en astrophysique nucléaire. Par exemple, il a été postule que cette réaction pourrait résoudre, au moment de la nucléosynthèse du big bang, le problème du Lithium. Il est clair, aujourd'hui, que ce n'est pas la solution, cependant, elle a un rôle dans la production de boron lors des supernovae de type Ic. Une autre façon d’étudier les réactions (a,g) est d'utiliser la cinématique inverse. L’idée est d'envoyer un faisceau d'ions lourd sur une cible d’hélium. Ce type de cinématique permet de détecter, avec une bonne efficacité, le noyau lourd de recul produit si le faisceau qui n'a pas interagit avec la cible, en est correctement séparé. Les séparateurs de masses, comme St. George, sont construit dans ce but. St. George sera impliquer dans la mesure de sections efficaces de réaction d’importance pour le processus s comme 16O(a,g)20Ne. / The study of (a,g) reactions of astrophysical interest is quite vast. These reactions play an important role in the quiescent Helium burning phase of stars, in big bang nucleosynthesis and in most explosive stellar scenarios. The studies of (a,g) reactions involving stable beams are performed in various ways. I have been concentrating on two of them. The first one is studying these reactions in direct kinematics by detecting the produced gamma rays. This is what I did during my thesis to measure the cross section of 7Li(a,g)11B. It has been studied throughout the years for several purposes in nuclear astrophysics. For example, it was postulated it could solve the big bang nucleosynthesis Lithium problem. Nowadays, it is clear it does not.However, this reaction plays a role in the production of Boron during type Ic Supernovae. Another way to study (a,g) reactions is to use inverse kinematics. The idea is to send a heavy element beam on a Helium target. This kind of kinematics allows for the detection, with good efficiency, of the heavy recoil product if the beam that did not interact in the target is properly separated. Recoil mass separators, like St. George, are built for this purpose. St. George will be involved in measuring cross sections of reaction important for the s-process like 16O(a,g)20Ne.
3

Hybrid Solid-State Hydrogen Storage Materials

Benge, Kathryn Ruth January 2008 (has links)
This thesis investigates the chemistry of ammonia borane (NH3BH3) relevant to the development of hydrogen storage systems for vehicular applications. Because of its high hydrogen content and low molecular weight ammonia borane has the potential to meet stringent gravimetric hydrogen storage targets of gt;9 wt%. Two of the three moles of H2 in ammonia borane can be released under relatively mild conditions, with the highest gravimetric yield obtained in the solid-state. However, ammonia borane does not deliver sufficient H2 at practical temperatures and the products formed upon H2 loss are not amenable to regeneration back to the parent compound. The literature synthesis of ammonia borane was modified to facilitate large scale synthesis, and the deuterated analogues ND3BH3 and NH3BD3 were prepared for the purpose of mechanistic studies. The effect of lithium amide on the kinetics of dehydrogenation of ammonia borane was assessed by means of solid-state reaction in a series of specific molar ratios. Upon mixing lithium amide and ammonia borane, an exothermic reaction ensued resulting in the formation of a weakly bound adduct with an H2N...BH3-NH3 environment. Thermal decomposition at or above temperatures of 50eg;C of this phase was shown to liberate gt;9 wt% H2. The mechanism of hydrogen evolution was investigated by means of reacting lithium amide and deuterated ammonia borane isotopologues, followed by analysis of the isotopic composition of evolved gaseous products by mass spectrometry. From these results, an intermolecular multi-step reaction mechanism was proposed, with the rates of the first stage strongly dependent on the concentration of lithium amide present. Compounds exhibiting a BN3 environment (identified by means of solid-state sup1;sup1;B NMR spectroscopy) were formed during the first stage, and subsequently cross link to form a non-volatile solid. Further heating of this non-volatile solid phase ultimately resulted in the formation of crystalline Li3BN2 - identified by means of powder X-ray diffractometry. This compound has been identified as a potential hydrogen storage material due to its lightweight and theoretically high hydrogen content. It may also be amenable to hydrogen re-absorption. The LiNH2/CH3NH2BH3 system was also investigated. Thermal decomposition occurred through the same mechanism described for the LiNH2/NH3BH3 system to theoretically evolve gt;8 wt% hydrogen. The gases evolved on thermal decomposition were predominantly H2 with traces of methane detected by mass spectrometry.
4

Diastereoselective α-Alkylation of Chiral β-Borylated Esters

Perfetti, Michael Thomas 13 January 2010 (has links)
The use of boron in the synthesis and development of asymmetric methodologies and various biological and medicinal compounds has increased significantly over the last decade. This thesis reports the development of a novel diastereoselective reaction for the α-alkylation of chiral β-borylated esters. We propose that standard deprotonation of chiral β-borylated esters with lithium diisopropylamide (LDA) leads to the formation of a boron"ate" intermediate that upon treatment with an alkylation reagent collapses to provide chiral α, β-substituted boronic esters with a high degree of diastereoselectivity. This reaction is powerful in that a wide range of chiral β-borylated ester substrates can be employed that possess varying degrees of substitution and steric bulk. Results show that the reaction is syn-selective and provides yields of up to 60%, with diastereomeric ratios as high as (9.7:1). Additionally, alkylation products from bulkier tert-butyl esters provide higher DR values compared to those of methyl esters that possess the same β-functional groups. Several techniques were utilized to elucidate the mechanism of this reaction including variations of reaction temperature and equivalents of base, and also real-time analysis of the reaction by ¹¹B NMR experiments. / Master of Science
5

Organic-inorganic hybrid materials for boron removal from aqueous media

Sanfeliu Cano, Cristina 02 May 2016 (has links)
[EN] The present PhD thesis is centred in the design (using concepts of supramolecular chemistry), synthesis and characterization of different hybrid organic-inorganic materials for boron removal from aqueous media. The interaction between boron and organic groups, polyols, used in the development of these new adsorbents is also studied. In the first part of the thesis it is presented a brief review of supramolecular chemistry concepts, chemistry of boron and also the main methods for boron removal (first chapter) and, also, the objectives of this thesis (second chapter). The third chapter exposes the results obtained by using a ceramic foam as macroscopic support for active materials for boron removal. This support is previously "impregnated" with an inorganic silica mesoporous material (UVM-7) and, in a second step, it is functionalized with an organic group with high boron affinity (gluconamide). This organic group, which works as an adsorbent, remains anchored to a macroscopic support, which will facilitate the use of these materials in industrial applications. Once the material is synthetized their boron adsorption and elimination abailability in aqueous media is studied and its ulterior reutilization. The fourth chapter of the PhD thesis is focused on the preparation of low cost materials for boron adsorption from water. In first place, it is used, as inorganic scaffolding, UVM-7 material, a mesoporous silica phase with a bimodal pore system. This material has a high boron adsorption capacity after its functionalization with the polyalcohol (as it is shown in the previous chapter) nevertheless, the reagents used in the synthesis tetraethylorthosilicate, as silica source, and hexadecyltrimethylammonium bromide, as templating agent are so expensive that they induce a high cost of final materials. In this chapter is presented as an alternative another materials which are able to perform as inorganic scaffolds: UVM-11 (surfactant-free mesoporous material), two silica xerogels with pores within the mesoporous range and comercial high surface area silica fume were prepared. Once all the materials are synthetized they are functionalized with gluconamides which are the active compounds for boron adsorption. Finally, a comparative study of the boron adsorption capacities in water is carried out. Low cost materials present comparable boron removal to those of higher cost and comercially abailable materials. Finally, in the fith chapter of this PhD thesis, the adsorption mechanism of boron on the active materials (based on UVM-7 as inorganic support) is studied using solid Nuclear Magnetic Resonance measures of 11B and 13C and using techniques as Magic Angle Sppining, crossed polarization and heteronuclear polarization disacoplament. To do that, a hybrid material composed by UVM-7 matrix grafted with gluconamide is prepared and then the solid is put in contact with different boron quantities. Final solids are characterized through 13C and 11B NMR, showing the formation of boronesters between gluconamide diol groups and boron adsorbed. When low boron concentration is used, bisquelate complexes are formed (B:glucosa = 1:2), however with higher concentrations monoquelate complexes are formed (B:glucosa = 1:1). This work was carried out in collaboration with the research group of "sol-gel materials and NMR", appertaining to the center of "Chimie de la matière condensée de Paris" of the "Université Pierre et Marie Curie". / [ES] La presente tesis doctoral está dedicada al diseño (empleando conceptos de química supramolecular), síntesis y caracterización de diferentes materiales híbridos orgánico-inorgánicos para la eliminación de boro en medios acuosos. También se ha procedido a estudiar detalladamente la interacción del boro con las agrupaciones orgánicas, polialcoholes, empleadas en el desarrollo de estos nuevos adsorbentes. En la primera parte de la tesis de presenta una introducción en la que se revisa los conceptos de química supramolecular, química del boro y los principales métodos de eliminación de boro (primer capítulo) y, también, se exponen los objetivos de la tesis (segundo capítulo). Ya en el tercer capítulo se exponen los resultados obtenidos empleando una esponja cerámica como soporte macroscópico para los materiales activos frente a la eliminación de boro. Este soporte se "impregnan" previamente con un material inorgánico silíceo mesoporoso (UVM-7) y, en una fase posterior, se funcionaliza con un grupo orgánico con alta afinidad hacia el boro (gluconamida). El grupo orgánico que funcionará como adsorbente queda así anclado a un soporte de tamaño macroscópico que facilitará la aplicación de estos materiales a gran escala. Una vez preparado y caracterizado se estudió la capacidad del material para adsorber y eliminar boro de medios acuosos y su posterior reutilización. En el cuarto capítulo de la tesis doctoral se aborda la preparación de materiales adsorbentes de bajo coste económico para la eliminación de boro en medios acuosos. En primer lugar se emplea, como soporte inorgánico, UVM-7 una sílice mesoporosa con un sistema bimodal de poros. Este material tiene una capacidad de adsorción de boro muy elevada una vez funcionalizado con el correspondiente polialcohol (tal y como se expone en el capítulo anterior) sin embargo los reactivos para su síntesis tetraetilortosilicato como fuente de sílice y bromuro de cetiltrimetilamonio como agente director de estructura son muy caros con lo que el material final presenta un elevado coste. En este capítulo se presenta como alternativa otros materiales que puedan actuar como soportes inorgánicos: UVM-11, material mesoporoso que no requiere de agente director de estructura en su síntesis, dos xerogeles con poros en el rango meso y una sílice comercial nanoparticulada de elevada superficie específica. Una vez sintetizados y caracterizados los cinco soportes se funcionalizaron con gluconamidas, que son los componentes activos frente a la adsorción de boro. Finalmente, se realiza un estudio comparativo de la capacidad de eliminación de boro de los cinco materiales preparados. Los materiales de bajo coste estudiados presentan una capacidad de eliminación de boro comparable a los materiales de mayor coste y a los materiales comercialmente disponibles. Por último, en el capítulo cinco de esta tesis doctoral, se aborda el estudio del mecanismo de adsorción del boro en los materiales activos preparados (basados en UVM-7 como soporte inorgánico) mediante medidas de resonancia magnética nuclear de sólidos, tanto de 13C como de 11B empleando las técnicas de rotación en ángulo mágico, polarización cruzada, y el desacoplamiento dipolar heteronuclear. Para ello se prepara un material híbrido formado por una matriz de UVM-7 funcionalizada con gluconamidas y este sólido se pone en contacto con diferentes cantidades de boro. Los sólidos finales se caracterizan mediante RMN de 13C y de 11B, observándose la formación de boroesteres entre los grupos diol de las gluconamidas ancladas y el boro adsorbido. Cuando la concentración de boro empleada es baja se forman complejos bisquelados (B:glucosa = 1:2) mientras que a concentraciones altas empiezan a formarse complejos monoquelados (B:glucosa = 1:1). Este trabajo se llevó a cabo en colaboración con el grupo de investigación de "Materiales sol-gel y RMN", perteneciente al centro "Chimie de la matiè / [CAT] La present tesi doctoral està dedicada al disseny (empleant conceptes de química supramolecular), síntesi i caracterització de diferents materials híbrids orgànico-inorgànics per a la el¿liminació de bor en medi aquòs. També s'ha precedit a estudiar detalladament la interacció del bor amb les agrupacions orgàniques, polialcohols, empreats en el desenvolupament d'aquestos nous adsorbents. En la primera part de la tesi es presenta una introducció en la que es revisen els conceptes de química supramolecular, química del bor i els principals mètodes de el¿liminació de bor (primer capítol) i, també, s'exposen els objectius de la tesi (segon capítol). Ja en el tercer capítol s'exposen els resultats obtinguts empreant una esponja ceràmica com a suport macroscòpic per als materials actius front a l'el¿liminació del bor. Aquest suport s'impregna prèviament amb un material inorgànic de sílice mesoporós (UVM-7) i, en una següent fase, es funcionalitza amb un grup orgànic amb alta afinitat cap al bor (gluconamida). El grup orgànic que funcionarà com a adsorbent queda aixina anclat a un suport de tamany macroscòpic que facil¿litarà l'aplicació d'aquestos materials a gran escala. Una vegada preparat i caracteritzat s'estudia la capacitat del material per a adsorber i el¿liminar bor en medi aquós i la seua posterior reutilització. Al quart capítol de la tesi doctoral s'aborda la preparació de materials adsorbents de baix cost econòmic per a l'eliminació de bor en medi aquòs. En primer lloc, s'empra, com a suport inorgànic, UVM-7 una sílice mesoporosa amb un sistema bimodal de porus. Aquest material té una capacitat d'adsorció molt elevadadeprés de la seua funcionalització amb el corresponent polialcohol (tal i com s'exposa al capítol anterior), no obstant això els reactius que s'utilitzen per a la seua síntesi tetraetilortosilicat com a font de sílice i bromur de cetiltrimetilamoni com agent director d'estructura són molt cars, per tant el material final presenta un elevat cost. En aquest capítol es presenta com alternativa altres materials que puguen actuar com a suports inorgànics: UVM-11, material mesoporòs que no requereix d'agent director d'estructura durant la seua síntesi, dos xerogels en porus en el rang meso i una sílice comercial nanoparticulada amb elevada superficie específica. Una vegada sintetitzats i caracteritzats els cinc suports es funcionalitzen en gluconamides, que són els components actius front a la adsorció de bor. Finalment, es realitza un estudi comparatiu de la capacitat d'el¿liminació de bor dels cinc materials preparats. Els materials de baix cost estudiats presenten una capacitat de eliminació de bor semblant als materials de major cost i als materials comercialment disponibles. Per últim, al capítol cinc d'aquesta tesi doctoral, s'aborda l'estudi del mecanisme d'adsorció de bor als materials actius preparats (basats en UVM-7 com a suport inorgànic) mitjançant medides de resonància magnética nuclear de sólids, tant de 13C com de 11B emprant tècniques de rotació en àngul màgic, polarització creuada, i el desacoplament dipolar heteronuclear. Per a ell es prepara un material híbrid format per una matriu de UVM-7 funcionalitzada amb gluconamides i aquest sòlid es posa en contacte amb diferents quantitats de bor. Els sòlids finals es caracteritzen mitjançant RMN de 13C i de 11B observant-se la formació de borésters entre els grups diol de les gluconamides anclades i el bor adsorbit. Quan la concentració de bor emprada és baixa es formen complexos bisquelats (B:glucosa = 1:2) mentre que a concentracions més altes comencen a formar-se complexos monoquelats (B:glucosa = 1:1). Aquest treball és va realitzar ne col¿laboració amb el grup d'investigació de "Materials sol-gel i RMN", perteneixent al centre "Chimie de la matière condensée de Paris" de la "Université Pierre et Marie Curie". / Sanfeliu Cano, C. (2016). Organic-inorganic hybrid materials for boron removal from aqueous media [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63277 / TESIS
6

Synthesis of New Classes of Ionic Liquids and Polymeric Ionic Liquids and their Applications in Microextraction Techniques

Joshi, Manishkumar Dilipkumar January 2013 (has links)
No description available.
7

Sequence stratigraphic characterisation of petroleum reservoirs in Block 11b/12b of the Southern Outeniqua Basin

Nformi, Emmanuel Nfor January 2011 (has links)
<p>The main purpose of this study was to identify and characterize the various sand prone depositional facies in the deepwater Southern Outeniqua Basin which generally tend to form during&nbsp / lowstand (marine regression) conditions producing progradational facies. It made use of sequence stratigraphy and turbidite facies models to predict the probable location of deepwater&nbsp / reservoirs in the undrilled Southern Outeniqua Basin using data from basin margin Pletmos Basin and the deepwater Southern Outeniqua Basin. Basin margin depositional packages were&nbsp / correlated in time and space with deepwater packages. It was an attempt at bridging the gap between process-related studies of sedimentary rocks and the more traditional economic geology&nbsp / f commercial deposits of petroleum using prevailing state-of-the-art in basin analysis. It enabled the most realistic reconstructions of genetic stratigraphy and offered the greatest&nbsp / application in exploration. Sequence stratigraphic analysis and interpretation of seismics, well logs, cores and biostratigraphic data was carried out providing a chronostratigraphic framework of the study area within which seismic facies analysis done. Nine (9) seismic lines that span the shallow/basin margin Pletmos basin into the undrilled deepwater Southern Outeniqua basin were analysed and interpreted and the relevant seismic geometries were captured. Four (4) turbidite depositional elements were identified from the seismic lines: channel, overbank deposits,&nbsp / haotic deposits and basin plain (basin floor fan) deposits. These were identified from the relevant seismic geometries (geometric attributes) observed on the 2D seismic lines. Thinning attributes, unconformity attributes and seismic facies attributes were observed from the seismic lines. This was preceded by basic structural analyses and interpretation of the&nbsp / seismic lines. according to the structural analysis and interpretation, deposition trended NW-SE and NNW-SSE as we go deepwater into the Southern Outeniqua basin. Well logs from six (6)&nbsp / of the interpreted wells indicated depositional channel fill as well as basin floor fans. This was identified in well Ga-V1 and Ga-S1 respectively. A bell and crescent shape gamma ray log&nbsp / signature was observed in well Ga-V1 indicating a fining up sequence as the channel was abandoned while an isolated massive mound-shape gamma ray log signature was observed in&nbsp / Ga-S1 indicating basin plain well-sorted sands. Core analyses and interpretation from two southern-most wells revealed three (3) facies which were derived based on Walker&lsquo / s 1978, turbidite&nbsp / facies. The observed facies were: sandstone, sand/shale and shale facies. Sequence stratigraphic characterisation of petroleum reservoirs in block 11b/12b of the Southern Outeniqua&nbsp / Basin. Cores of well Ga-V1 displayed fine-grained alternations of thin sandstone beds and shales belonging to the thin-bedded turbidite facies. This is typical of levees of the upper fan channel but&nbsp / could easily be confused with similar facies on the basin plain. According to Walker, 1978 such facies form under conditions of active fan progradation. Ga-S1 cores displayed not only classic&nbsp / turbidite facies where there was alternating sand and shale sections but showed thick uninterrupted sections of clean sands. This is typical of basin plain deposits. Only one well had&nbsp / biostratigraphic data though being very limited in content. This data revealed particular depth sections and stratigraphic sections as having medium to fast depositional rates. Such rates are&nbsp / characteristic of turbidite deposition from turbidity currents. This study as well as a complementary study by Carvajal et al., 2009 revealed that the Southern Outeniqua basin is a sand-prone&nbsp / basin with many progradational sequences in which tectonics and sediment supply rate have been significant factors (amongst others such as sea level change) in the formation of these&nbsp / deepwater sequences. In conclusion, the Southern Outeniqua basin was hereby seen as having a viable and unexplored petroleum system existing in this sand prone untested world class.</p>
8

Sequence stratigraphic characterisation of petroleum reservoirs in Block 11b/12b of the Southern Outeniqua Basin

Nformi, Emmanuel Nfor January 2011 (has links)
<p>The main purpose of this study was to identify and characterize the various sand prone depositional facies in the deepwater Southern Outeniqua Basin which generally tend to form during&nbsp / lowstand (marine regression) conditions producing progradational facies. It made use of sequence stratigraphy and turbidite facies models to predict the probable location of deepwater&nbsp / reservoirs in the undrilled Southern Outeniqua Basin using data from basin margin Pletmos Basin and the deepwater Southern Outeniqua Basin. Basin margin depositional packages were&nbsp / correlated in time and space with deepwater packages. It was an attempt at bridging the gap between process-related studies of sedimentary rocks and the more traditional economic geology&nbsp / f commercial deposits of petroleum using prevailing state-of-the-art in basin analysis. It enabled the most realistic reconstructions of genetic stratigraphy and offered the greatest&nbsp / application in exploration. Sequence stratigraphic analysis and interpretation of seismics, well logs, cores and biostratigraphic data was carried out providing a chronostratigraphic framework of the study area within which seismic facies analysis done. Nine (9) seismic lines that span the shallow/basin margin Pletmos basin into the undrilled deepwater Southern Outeniqua basin were analysed and interpreted and the relevant seismic geometries were captured. Four (4) turbidite depositional elements were identified from the seismic lines: channel, overbank deposits,&nbsp / haotic deposits and basin plain (basin floor fan) deposits. These were identified from the relevant seismic geometries (geometric attributes) observed on the 2D seismic lines. Thinning attributes, unconformity attributes and seismic facies attributes were observed from the seismic lines. This was preceded by basic structural analyses and interpretation of the&nbsp / seismic lines. according to the structural analysis and interpretation, deposition trended NW-SE and NNW-SSE as we go deepwater into the Southern Outeniqua basin. Well logs from six (6)&nbsp / of the interpreted wells indicated depositional channel fill as well as basin floor fans. This was identified in well Ga-V1 and Ga-S1 respectively. A bell and crescent shape gamma ray log&nbsp / signature was observed in well Ga-V1 indicating a fining up sequence as the channel was abandoned while an isolated massive mound-shape gamma ray log signature was observed in&nbsp / Ga-S1 indicating basin plain well-sorted sands. Core analyses and interpretation from two southern-most wells revealed three (3) facies which were derived based on Walker&lsquo / s 1978, turbidite&nbsp / facies. The observed facies were: sandstone, sand/shale and shale facies. Sequence stratigraphic characterisation of petroleum reservoirs in block 11b/12b of the Southern Outeniqua&nbsp / Basin. Cores of well Ga-V1 displayed fine-grained alternations of thin sandstone beds and shales belonging to the thin-bedded turbidite facies. This is typical of levees of the upper fan channel but&nbsp / could easily be confused with similar facies on the basin plain. According to Walker, 1978 such facies form under conditions of active fan progradation. Ga-S1 cores displayed not only classic&nbsp / turbidite facies where there was alternating sand and shale sections but showed thick uninterrupted sections of clean sands. This is typical of basin plain deposits. Only one well had&nbsp / biostratigraphic data though being very limited in content. This data revealed particular depth sections and stratigraphic sections as having medium to fast depositional rates. Such rates are&nbsp / characteristic of turbidite deposition from turbidity currents. This study as well as a complementary study by Carvajal et al., 2009 revealed that the Southern Outeniqua basin is a sand-prone&nbsp / basin with many progradational sequences in which tectonics and sediment supply rate have been significant factors (amongst others such as sea level change) in the formation of these&nbsp / deepwater sequences. In conclusion, the Southern Outeniqua basin was hereby seen as having a viable and unexplored petroleum system existing in this sand prone untested world class.</p>
9

Sequence stratigraphic characterisation of petroleum reservoirs in Block 11b/12b of the Southern Outeniqua Basin

Nfor, Nformi Emmanuel January 2011 (has links)
Magister Scientiae - MSc / The main purpose of this study was to identify and characterize the various sand prone depositional facies in the deepwater Southern Outeniqua Basin which generally tend to form during lowstand (marine regression) conditions producing progradational facies. It made use of sequence stratigraphy and turbidite facies models to predict the probable location of deepwater reservoirs in the undrilled Southern Outeniqua Basin using data from basin margin Pletmos Basin and the deepwater Southern Outeniqua Basin. Basin margin depositional packages were correlated in time and space with deepwater packages. It was an attempt at bridging the gap between process-related studies of sedimentary rocks and the more traditional economic geology f commercial deposits of petroleum using prevailing state-of-the-art in basin analysis. It enabled the most realistic reconstructions of genetic stratigraphy and offered the greatest application in exploration. Sequence stratigraphic analysis and interpretation of seismics, well logs, cores and biostratigraphic data was carried out providing a chronostratigraphic framework of the study area within which seismic facies analysis done. Nine (9) seismic lines that span the shallow/basin margin Pletmos basin into the undrilled deepwater Southern Outeniqua basin were analysed and interpreted and the relevant seismic geometries were captured. Four (4) turbidite depositional elements were identified from the seismic lines: channel, overbank deposits, haotic deposits and basin plain (basin floor fan) deposits. These were identified from the relevant seismic geometries (geometric attributes) observed on the 2D seismic lines. Thinning attributes, unconformity attributes and seismic facies attributes were observed from the seismic lines. This was preceded by basic structural analyses and interpretation of the seismic lines. according to the structural analysis and interpretation, deposition trended NW-SE and NNW-SSE as we go deepwater into the Southern Outeniqua basin. Well logs from six (6) of the interpreted wells indicated depositional channel fill as well as basin floor fans. This was identified in well Ga-V1 and Ga-S1 respectively. A bell and crescent shape gamma ray log signature was observed in well Ga-V1 indicating a fining up sequence as the channel was abandoned while an isolated massive mound-shape gamma ray log signature was observed in Ga-S1 indicating basin plain well-sorted sands. Core analyses and interpretation from two southern-most wells revealed three (3) facies which were derived based on Walker‘s 1978, turbidite facies. The observed facies were: sandstone, sand/shale and shale facies. Sequence stratigraphic characterisation of petroleum reservoirs in block 11b/12b of the Southern Outeniqua Basin. Cores of well Ga-V1 displayed fine-grained alternations of thin sandstone beds and shales belonging to the thin-bedded turbidite facies. This is typical of levees of the upper fan channel but could easily be confused with similar facies on the basin plain. According to Walker, 1978 such facies form under conditions of active fan progradation. Ga-S1 cores displayed not only classic turbidite facies where there was alternating sand and shale sections but showed thick uninterrupted sections of clean sands. This is typical of basin plain deposits. Only one well had biostratigraphic data though being very limited in content. This data revealed particular depth sections and stratigraphic sections as having medium to fast depositional rates. Such rates are characteristic of turbidite deposition from turbidity currents. This study as well as a complementary study by Carvajal et al., 2009 revealed that the Southern Outeniqua basin is a sand-prone basin with many progradational sequences in which tectonics and sediment supply rate have been significant factors (amongst others such as sea level change) in the formation of these deepwater sequences. In conclusion, the Southern Outeniqua basin was hereby seen as having a viable and unexplored petroleum system existing in this sand prone untested world class. / South Africa
10

Chromophore Arylboronsäureester und ihr Komplexbildungsverhalten gegenüber Lewis-Basen

Oehlke, Alexander 14 December 2010 (has links) (PDF)
Die vorliegende Arbeit hat die Synthese und Charakterisierung von chromophoren Arylboronsäureestern mit besonderem Augenmerk auf einer breiten strukturellen Variation zum Inhalt. An dieser Verbindungsklasse wird die Wechselwirkung mit Lewis-Basen tiefgehend untersucht. Die Koordination von Lewis-Basen am Bor-Atom führt zu einer Beeinflussung der elektronischen Eigenschaften des borbasierten Substituenten, wobei der Charakter eines direkt am Bor-Atom gebundenen pi-Elektronensystems von pull zu push-pull geschaltet werden kann. In der vorliegenden Arbeit wird beschrieben, wie geometrische und elektronische Strukturmerkmale von boronsäureesterfunktionalisierten Chromophoren durch die Lewis-Säure-Base-Wechselwirkung am Bor-Atom beeinflusst werden. Die Veränderung von molekularen Eigenschaften wird mit Hilfe der UV/vis-Absorptions- und Fluoreszenzspektroskopie, 1H- und 11B-NMR-Spektroskopie sowie mit röntgendiffraktometrischen Methoden untersucht. Die experimentellen Daten werden durch quantenchemische Berechnungen auf DFT-Niveau unterstützt.

Page generated in 0.4163 seconds