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1
Foucart, Brice. "Observation et modélisation de la Formation de Nouvelles Particules (FNP) au sein du panache volcanique du Piton de la Fournaise." Thesis, La Réunion, 2019. http://www.theses.fr/2019LARE0014/document.
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L'activité volcanique peut représenter une source naturelle de pollution atmosphérique. Cette pollution peut engendrer une dégradation de la qualité de l'air, affecter la santé humaine et perturber la sécurité aérienne. Le Piton de la Fournaise à La Réunion est l'un des volcans basaltique les plus actifs au monde. Ses éruptions sporadiques génèrent des panaches volcaniques essentiellement constitués de gaz et de nanoparticules qui se propagent dans l'atmosphère. En journée, la formation d'oxydants (photolyse) permet d'oxyder une partie du dioxyde de soufre en acide sulfurique. Les molécules d'H2SO4 peuvent réagir avec les molécules d'eau atmosphérique pour former des embryons via la nucléation binaire homogène. Puis, ces embryons grossissent grâce aux processus de condensation et/ou coagulation conduisant alors à la formation d'un aérosol volcanique submicronique. Cette thèse vise à observer, comprendre et modéliser les processus de Formation de Nouvelles Particules (FNP) au sein des panaches volcaniques. De ce fait, elle s'organise en deux parties. La première se base sur les données recueillies lors de la campagne multidisciplinaire STRAP menée à l’observatoire du Maïdo et au Piton de la Fournaise en 2015. Elle expose les résultats issus d’une double analyse de la fréquence et de l’intensité des événements de FNP à l’observatoire. Tandis que la première analyse s’intéresse aux processus en l’absence du panache volcanique, la seconde met en exergue les spécificités de la FNP liées à sa présence au Maïdo. La seconde partie s'axe autour de la modélisation d'abord 0D puis 3D des processus de FNP au sein des panaches volcaniques via le modèle atmosphérique Méso-NHVolcanic activity can be a natural source of air pollution. This pollution can lead to a deterioration in air quality, affect human health and disrupt aviation safety. The Piton de la Fournaise in Reunion Island is one of the most active basaltic volcanoes in the world. Its sporadic eruptions generate volcanic plumes consisting mainly of gases and nanoparticles that spread in the atmosphere. During the day, a part of the sulphur dioxide can be oxidized to sulphuric acid thanks to oxidants production (photolysis). H2SO4molecules tend to react with atmospheric water molecules and form clusters via homogeneous binary nucleation. Then, these clusters grow by condensation and/or coagulation processes leading to the formation of a submicronic volcanic aerosol. This thesis aims to observe, understand and model the New Particle Formation (NPF) processes within volcanic plumes. Consequently, it is organized in two parts. The first is based on the data gathered during the multidisciplinary STRAP campaign conducted at both the Maïdo Observatory and Piton de la Fournaise volcano in 2015. It presents the results from a dual analysis of the NPF events frequency and intensity at the observatory. While the first analysis focuses on processes in the absence of the volcanic plume, the second highlights the specificities of the NPF related to the presence of the plume at Maïdo. The second part focuses on 0D then 3D NPF processes modelling within volcanic plumes via the Meso-NH atmospheric model
2
Atkin, Ian. "Improvement of sulphur dioxide yield from the sulphuric acid thermal decomposition process by membrane separation." Thesis, University of Sheffield, 2010. http://etheses.whiterose.ac.uk/14532/.
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This work investigates the feasibility of applying high temperature oxygen separation to the sulphuric acid decomposition process, a step used in large scale hydrogen production processes currently under development. Porous and dense membranes are both considered. Equilibrium calculations show yttria-stabilised zirconia (YSZ), combined with platinum electrodes, to be a candidate membrane. Process simulations show the potential sulphur dioxide yield increases that could be achieved through the use of a high temperature oxygen separation membrane in two different configurations. Bespoke experimental apparatus was designed, procured and assembled in order to investigate the oxygen flux through YSZ membranes in the presence of sulphur dioxide, during external voltage application. Experiments were performed in the 700 - 900°C temperature range. Results show that oxygen permeation through YSZ membranes occurs under these conditions. A decrease in oxygen permeation with time was observed and attributed to sulphur dioxide adsorption on to the platinum electrodes. Future work would concentrate on using variable applied voltages to reduce this performance decrease.
3
Fu, Man On. "Novel adsorbents for sulphur dioxide removal /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202009%20FU.
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Thompson, Linda Helen. "Reactions in liquid sulphur dioxide based media." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335469.
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5
Buckenham, A. H. "Effects of sulphur dioxide on stomatal functioning." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378436.
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6
Zaft, Paul E. "A microcomputer compensated sensor for sulphur dioxide." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46626.
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7
Harman, Neil F. "Aspects of the lithium-sulphur dioxide cell." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/33142.
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An open electrolytic cell has been designed and constructed for use in a dry environment. This was used to investigate the passivation processes concerned with both the lithium and the carbon (SO2) electrodes. A.c. impedance techniques have been used in both two and three terminal cell systems in order to study the kinetics of the electrode processes. Effects of temperature, state-of-charge and reverse cell operation have been studied. Computer simulations were made of the growth of crystals on a flat (Li) surface and the resulting growth transients connecting current and time were derived. This model was extended to simulate the porous carbon (SO2) electrode and the utilisation of the carbon as a function of the depth of reaction penetration into the electrode is devised for both potentiostatic and galvanostatic discharging.
8
Rao, Sumitrananda N. R. "Novel adsorbents using metal complexes." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/10200.
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Mulligan, David John. "Reduction of sulphur dioxide over transition metal sulphides." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61916.
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Famulari, Daniela. "Surface-atmosphere exchange of ammonia and sulphur dioxide." Thesis, University of Edinburgh, 2005. http://hdl.handle.net/1842/10883.
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Field measurements of the surface – atmosphere exchange of SO2 and NH3 have been made using two very different micrometeorological methods, a long term averaging method based on flux-gradient principles and an eddy covariance method, using a tunable diode laser fast response gas analysis system. The field data are then applied in surface-atmosphere models to calculate deposition of pollutant gases at the regional scale. The Time Averaged Gradient system (TAG) has been developed following a prototype implemented during a pilot study in 1998. The main goal of the TAG is to provide direct long-term average (1 to 4 weeks) flux-gradient measurements for a range of trace gas species, between atmosphere and terrestrial surfaces. Over daily periods, atmospheric conditions can range from high stability, where the vertical gradients of ambient concentration are enhanced due to very small diffusivity, to highly unstable conditions, in which concentration gradients are small due to the intense turbulent activity of the surface layer. By sampling continuously over a long-term period, the large vertical gradients generated by high stability would lead to an over-estimate of the actual flux; therefore it is necessary to avoid the bias due to these processes. To overcome this problem, the TAG system operates conditionally, sampling the micrometeorological variables within a carefully defined range of stability. A data series of five years, from 1999 to 2003, for SO2 and a data series of two years, from 2001 to 2003 for NH3 has been obtained at Auchencorth Moss, a field site in Southern Scotland. The measurements provided a characterisation of the chemical climate, meteorology, turbulent characteristics, as well as deposition-emission rates at the field site. A comparison with a continuous flux-gradient system running in parallel on the same field site allowed the reliability of the TAG system to be quantified: the correlation coefficients for u* and H show a very good agreement (above 90% in both cases) between TAG protocol and continuous system suggesting the removal of stable conditions from the sampling period doesn’t modify the evaluation of the turbulent fluxes, although it introduces a bias. The SO2 fluxes calculated omitting stable conditions under-estimate the fluxes of SO2 measured by the continuous system by providing fluxes that are the 77% of the values estimated with the continuous system. A second TAG system has been implemented to improve estimates of gradients and reduce uncertainty on the fluxes and to increase the data coverage. It has been tested on the Easter Bush field site (Southern Scotland) measuring NH3 fluxes form autumn 2001 to spring 2003. Field measurements of NH3 fluxes using an eddy covariance technique were made for a total of 60 days between July and October 2002 at intensively managed grassland in Southern Scotland. The collected data demonstrate the suitability of a Tuneable Diode Laser Absorption Spectroscopy (TDLAS) system coupled with a sonic anemometer for eddy covariance measurements.
11
Harrison, K. A. "The fate of sulphur dioxide in meat products." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233204.
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Henry, William John. "Annelation and pyrolysis reactions of 3-thiabicyclo[3.2.0]heptane-3,3-dioxide ring systems." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/15006.
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Mulligan, David John. "Reduction of sulphur dioxide over supported molybdenum sulphide catalysts." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39497.
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The reduction of sulphur dioxide with methane using various supported molybdenum catalysts has been studied. Catalysts were prepared using either alumina or a silica-alumina support. For the alumina supported catalysts, the molybdenum loadings of 5, 10 or 15% were used. These catalysts were sulphided using 12% H$ sb2$S in argon or a mixture of SO$ sb2$ and CH$ sb4$ in argon. The 15% $ rm Mo/Al sb2O sb3$ catalyst sulphided with H$ sb2$S was at least 1.5 times as active as the other alumina supported catalysts and had the highest yields of elemental sulphur and CO$ sb2$ and was 10 times as active as the silica-alumina supported catalyst with the same molybdenum loading. The addition of cobalt to the 15% $ rm Mo/Al sb2O sb3$ catalyst decreased the activity by 20%. Alumina supported molybdenum catalysts sulphided using a mixture of 25% SO$ sb2$, 25% CH$ sb4$ and 50% Ar were more active, and had higher yields of sulphur and CO$ sb2$ than alumina itself. However, these catalysts were not as active as catalysts with a similar molybdenum loading which were sulphided using H$ sb2$S because the H$ sb2$S sulphided catalysts had a higher MoS$ sb2$ content. Kinetic experiments were carried out using the H$ sb2$S sulphided 15% Mo/$ rm Al sb2O sb3$ catalyst. A rate expression was developed at the temperatures of 600, 625, and 650$ sp circ$C. The results indicate that the reaction is methane adsorption controlled.
14
Coetzee, Morné Pieter. "Upscaling of a sulphur dioxide depolarized electrolyzer / Coetzee, M.P." Thesis, North-West University, 2012. http://hdl.handle.net/10394/7001.
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In the last couple of years there has been a great need for finding alternative, cleaner burning fuel sources. This search has led to the development of various hydrogen technologies. The reason for this is that when burnt, hydrogen gas only forms water and oxygen as products. One of the methods used in the production of hydrogen gas is that of the electrolysis of sulphur dioxide which is facilitated by a sulphur dioxide depolarized electrolyzer. The electrolysis of sulphur dioxide has the advantage of requiring lower cell voltages in the electrolysis process when compared to the electrolysis of water.
This type of electrolyzer unfortunately suffers from low hydrogen gas production volumes. It was thought that by linearly increasing the reactions active area of the electrolyzer, the production volumes can be increased. A linearly upscaled 100cm2 cell was designed by using computer aided design software, such as SolidWorks, Cambridge Engineering Selector, EES and ANSYS. The cell was then constructed and tested to determine the effects of linearly upscaling. The results of the 100cm2 cell were compared to the results of a similar 25cm2 cell and results obtained from the literature. The 100cm2 cell exhibited very poor performance when compared to the other cells. The 100cm2 cell showed lower hydrogen production volumes at higher energy inputs than the 25cm2 cell and an 86cm2 stack assembly. It was concluded that creating stack assemblies with cells with smaller active areas would be much more efficient than linearly upscaling the active area of the cells.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Graham, N. K. "Metal chemistry in non-aqueous solutions containing sulphur dioxide." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373849.
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Phillips, Samantha Justine. "The ability of bryophytes to withstand sulphur dioxide pollution." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284357.
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Barrelet, Timothée. "Norway spruce as an environmental archive for sulphur dioxide /." [S.l.] : [s.n.], 2006. http://www.zb.unibe.ch/download/eldiss/05barrelet_t.pdf.
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Hong, Pui-Kwan Andrew Hoffmann Michael R. Hoffmann Michael R. "Catalytic oxidation of sulphur dioxide by heterogeneous cobalt-phthalocyanine /." Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechETD:etd-11082007-080528.
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Shaw, Andrew Charles. "The simultaneous solubilty of sulphur dioxide and oxygen in water for the hybrid sulphur thermochemical cycle." Thesis, University of Sheffield, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489067.
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Anthropogenic greenhouse gas emissions and rising oil prices call for a sustainable transportable energy source. Hydrogen is a promising replacement for carbon based fuels in vehicles. The HyS cycle, proposed by the Westinghouse Corporation, is a route to hydrogen production on a scale large enough to satisfy the requirements of the transport industry. The process is a hybrid thermochemical cycle based on the decomposition of sulphuric acid.
20
Gould, R. P. "The effects of gaseous sulphur dioxide and nitrogen dioxide on carbon allocation in plants." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377896.
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Renner, Christine Joan. "Interactive effects of sulphur dioxide, nitrogen dioxide and the winter environment on Lolium perenne." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254029.
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22
Hlabano-Moyo, Bongibethu Msekeli. "Separation of SO2/O2 using membrane technology / Bongibethu Msekeli Hlabano-Moyo." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9447.
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The Hybrid Sulphur process is one technology out of a multitude of known technologies responsible for hydrogen production. Within the latter hydrogen production cycle, it is pivotal to recover O2 as a by-product from a sulphuric acid decomposition reaction that produces SO2, H2O and O2. It is assumed that a simple phase separation stage carried out on the reaction products would liberate SO2 and O2 as a gaseous mixture leaving behind H2O in the liquid state.
Several separation technologies are available to effect SO2/O2 separation, but membrane technology has proved to be dearer due to simplicity of the technology, low capital and energy costs. It is a pity though that insignificant work has been done that considers the SO2/O2 binary system in the membrane technology context. Of the insignificant work done, non – commercial membranes were employed. It is on the latter background that the present study was proposed.
Six commercial membranes were selected from literature, two (Udel Polysulfone and Teflon AF 2400) of which are currently used in gas separation applications and the remainder (Hyflon M, Hyflon F, Halar and Nafion 117) not necessarily used as gas separation membranes but present a potential of separating SO2/O2. The inclusion of the latter four membranes sought to unearth unknown gas separation potentials of the membranes based on hypothetical 1 μm thick membranes.
A screening technique was employed to eliminate poor performing membranes through pure component permeation of SO2, O2, N2 and CO2. The use of the additional gases (N2 and CO2) was meant to allow the generation of a pool of data that would be used as a yardstick to compare to literature and thus validate the authenticity of the designed set up. The single permeation experiments were carried out at 25°C and at absolute gas feed pressures of 1 bar, 2 bar and 3 bar, with the exception of Hyflon F experiments that were carried out at 3.85 bar, 2.85 bar and 1.85 bar also at 25°C. The effect of pressure on gas permeability and ideal selectivity of all gases against O2 was investigated. Udel Polysulfone and Nafion 117 presented clearly evident pressure dependant SO2 permeabilities whilst CO2, N2 and O2 permeabilities were sluggishly dependant on pressure in all membranes. Gas flux in general increased with increasing pressure as pressure is essentially the driving force for permeability. Membrane screening for further investigation was then performed based on a compromise between SO2/O2 ideal selectivity and SO2 flux in hypothetical 1 μm thick membranes. Membranes that presented the best SO2/O2 selectivity include, Udel Polysulfone with SO2/O2 selectivities of 46, 58 and 314 at 1 bar, 2 bar and 3 bar respectively, Nafion 117 with SO2/O2 selectivities of 30, 35 and 40 at 1 bar, 2 bar and 3 bar respectively and Halar with a SO2/O2 selectivity of 17 at 3 bar. The best SO2 flux through hypothetical 1 μm thick membranes was manifested in Teflon AF 2400 with SO2 fluxes of 3.6 m3.m-2.hr-1, 5.9 m3.m-2.hr-1 and 9.9 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 Bar and 3 Bar respectively, Udel Polysulfone with SO2 fluxes of 0.13 m3.m-2.hr-1, 0.32 m3.m-2.hr-1 and 2.56 m3.m-2.hr-1 at trans-membrane pressures of 1 bar, 2 bar and 3 bar respectively and Nafion 117 with SO2 fluxes of 0.48 m3.m-2.hr-1, 1.03 m3.m-2.hr-1 and 1.79 m3.m-2.hr-1 at 1 bar, 2 bar and 3 bar trans-membrane pressures respectively. Despite Teflon AF 2400 presenting the highest SO2 flux, the poor SO2/O2 ideal selectivity ≈ 1 rendered the membrane unfit for further investigation. The low SO2 flux (0.02 m3.m-2.hr-1) presented by Halar also rendered the membrane unfit for further investigation despite the relatively fair SO2/O2 ideal selectivity of 17.
Binary permeation experiments were then performed on Udel Polysulfone and Nafion 117 after passing the single permeation screening test. Gas mixture compositions of (25 wt %:75 wt %, SO2:O2), (50 wt %:50 wt %, SO2:O2) and (75 wt %:25 wt %, SO2:O2) were employed. The binary permeation experiments were carried out at a temperature range of 15°C to 55°C and a SO2 feed partial pressure range of 1.1 ± 0.1 bar to 2.3 ± 0.1 bar.
The SO2 permeate composition increased with pressure and decreased with temperature in both Udel Polysulfone and Nafion 117. Udel Polysulfone presented a superior SO2/O2 separation potential, concentrating a (25 wt %:75 wt %, SO2:O2) gas mixture to (94 wt %:6 wt %, SO2:O2) in a single step at 15°C and 2.2 ± 0.1 bar SO2 feed partial pressure. Nafion 117 concentrated the same gas mixture to (87 wt %:13 wt %, SO2:O2) also in a single step at 15 °C and 2.4 ± 0.1 bar SO2 feed partial pressure. Based on hypothetical 1 μm thick membranes, Nafion 117 presented generally high SO2 molar fluxes in mixture with O2 of about a magnitude higher than the SO2 molar fluxes presented in Udel Polysulfone. Also, Nafion 117 proved to be less prone to plasticisation within the pressure range considered. Despite Udel Polysulfone presenting generally lower SO2 molar fluxes, Udel Polysulfone was deemed to be the ideal membrane for the current SO2/O2 separation application as thicknesses of 1 μm of Nafion the perfluorosulfonic acid based membrane are currently unknown and also Udel Polysulfone presented the best SO2/O2 separation capability. The latter findings are envisaged to prompt further research on the production of ultra-thin perfluoro-sulfonic acid based membranes for the current application.Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013
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Mchabe, Dursman. "Sulphur self–retention and sulphur dioxide capture with active calcium minerals in mineral–rich coals / Mchabe, D." Thesis, North-West University, 2011. http://hdl.handle.net/10394/7037.
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In order to provide information for the development of clean coal technology, the
sulphur self–retention and sulphur dioxide capturing properties of minerals present in
low grade coals was investigated. This study consisted of detailed mineral analyses of
coal and ash samples using results obtained from QEMSCAN and separate retention
(coal) and capture (ash) experiments with laboratory scale reactors. Typical South
African coal samples were used in this study. The ash content varied between 37.0 wt
% and 47.9 wt % with active calcium oxide (from calcite and dolomite) present
between 1.22 wt % and 4.92 wt %. The total sulphur content ranged between 0.60 wt
% and 1.90 wt % and was distributed between sulphate minerals, pyrite and
organically associated minerals in the coal macerals. The calcium to sulphur ratio
based on the active calcium ranged from 0.64 to 3.20. Sulphur self–retention
experiments (using powders of particle sizes ranging from 212 um to 300 um) were
carried out in a Packed Bed Balance Reactor at 900 oC at atmospheric pressure with
dry air for a period of 12 h. Transformation of a large fraction of the calcium bearing
minerals to sulphates was evident with total sulphur self–retention between 22.9% and
66.9% and the formation of calcium containing non–crystalline phases.
Thermogravimetric Analyzer experiments using 1 mm diameter coal particles were
carried out with the ash prepared (in situ with air) prior to the actual sulphation
determinations. After attaining a stable ash mass, the gas stream was changed to the
sulphur dioxide containing mixture (3000 ppm SO2, 8.0% CO2, 8.0% O2 and 83.7%
N2) and the increase in mass as a result of the reaction of sulphur dioxide (and
oxygen) with calcium oxide (calcite and dolomite) was recorded. Conversion of active
calcium bearing phases in the presence of sulphur dioxide containing gas mixture,
similar to the gas released during fluidised bed combustion, was employed to evaluate
the desulphurisation potential of the coal ashes, and it was found that nearly 40% of
the active calcium oxide was converted after 90 min reaction time at 900 ºC and that
no blocking of pores occurred as a result of solid phase changes. A mathematical
model based on the shrinking core model with diffusion through the product layer as
the determining mechanism was found to describe the overall reaction rate.Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Schmidt, Kurt A. G. "Solubility of sulphur dioxide in mixed polyethylene glycol dimethyl ethers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq22670.pdf.
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Mello, Marcus. "Adsorption of sulphur dioxide from multicomponent mixtures on hydrophobic zeolites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0032/NQ65466.pdf.
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Agha, Saad Arslan. "The control of sulphur dioxide emission from coal-fired stokers." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293819.
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Namor, Omar G. "Sorbic acid interaction with sulphur dioxide in model food systems." Thesis, University of Surrey, 1987. http://epubs.surrey.ac.uk/847780/.
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Sorbic acid and sulphur dioxide are often used together, as preservatives,in many foods. Sorbic acid is known to undergo degradation in aqueous solutions, and this degradation appears to be accelerated in the presence of sulphur dioxide. The interaction between sorbic acid and sulphur dioxide is the subject of this thesis. The work is subdivided into five chapters, as follows: The first chapter deals with the chemistry of sorbic acid acid and sulphur dioxide. The second chapter describes a study of the degradation products of sorbic acid, in aqueous systems, in the presence of sulphur dioxide and a possible mechanism for the occurrence of these products is proposed. Chapter three deals with the preparation and degradation of 6-[[13]C] sorbic acid in order to find evidence for, or against, the mechanism proposed in chapter two. It also gives details of syntheses attempted in order to obtain 6-[[13]C] sorbic acid. The interaction of sorbic acid and sulphur dioxide in real food systems is the subject of the fourth chapter. The food systems studied were mayonnaise, tomato puree, orange juice and cottage cheese. The effect of packaging on the rate of degradation of sorbic acid was also investigated. The final chapter deals with a microbiological study of two homologues of sorbic acid, 2,4-heptadienoic acid, 2,4-octadienoic acid. The fungicidal activity of these two compounds, towards selected fungi, was analysed. 4-0xobut-2-enoic acid, a degradation product of sorbic acid in aqueous systems, was also analysed as a possible fungistat.
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Esplin, Gordon John. "Heterogeneous reaction kinetics of sulphur dioxide and airborne limestone particles." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28379.
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The literature on acid rain provides evidence that large (>5 μm) alkaline particles in the atmosphere, which derived from surface soil, play an important role in mitigating the effect of acid rain. Not only do they help to neutralize acidity but they also are a source of nutrients to the terrestrial and aquatic environments.
While ground-up limestone has been added to the forests and the lakes of regions deficient in alkalinity, this mode of application is prohibitively expensive. An economic alternative method of distribution would utilize the advective and turbulent diffusive processes within the troposhere in order to supply limestone particles of approximately 10 μm diameter to the terrestrial and the aquatic environments. However, while the particles are being transported through the atmosphere they will also interact to some degree with the atmospheric pollutants (SO₂, NOx, photochemical oxidants, etc.). While the two-phase chemical interaction of water droplets and gaseous pollutants has been extensively studied, little is known about the reaction between limestone particles and gaseous pollutants under ambient conditions.
As a first step in understanding these processes laboratory experiments were conducted in order to measure the rate of the heterogeneous reaction between limestone particles and sulphur dioxide (SO₂) gas in clean humid air. Calcitic limestone (200-270 mesh Tyler) from Texada Island, B.C., was reacted with 30-80 ppb SO₂ at room temperature (17-22°C) over a humidity range of 70-100%. Ancillary experiments were also conducted to determine the maximum dissolution rate of these limestone particles in an acidic, aqueous environment. The overall rate (r) for the SO₂ reaction with Texada Island limestone was determined to be approximately first-order with respect to the SO₂ concentration and to be strongly dependent upon the relative humidity:
[Formula Omitted]
Limited experiments with precipitated dolomite indicated that it reacts with SO₂ somewhat faster than does the calcitic limestone.
A study of the individual mass transfer and reaction processes indicated that the rate limiting step for the overall reaction was the aqueous phase oxidation of the bisulphite ion. Limestone dissolution (determined experimentally), and estimated gas and aqueous phase diffusive processes, were not rate limiting. In a clean humid atmosphere, free of photochemical oxidants, a limestone aerosol would react very slowly with SO₂ (SO₂ removal rate of about 3x10⁻³% per hour).
However, in a humid polluted atmosphere rich in photochemical oxidants, similar to that responsible for acid fog and acid rain, the aqueous phase oxidation of dissolved SO₂ is not expected to be rate limiting. Under such conditions bisulphite dissociation: [Formula Omitted]
Therefore in humid, polluted atmospheres limestone aerosol will act as a "sink." for SO₂ for soluble photochemical oxidants, and probably also for HNO₃ (nitric acid). Since the oxidants are considered to be phytotoxic while the other pollutants are responsible for creating acid rain we conclude that the deployment of a limestone aerosol may have a positive impact on the atmospheric environment, besides being beneficial to the aquatic and terrestrial environments. It is strongly recommended that further research be done in this area in order to better quantify the rate processes, and perhaps also to identify practical methods for increasing the atmospheric concentration of alkaline aerosol in those geographic regions which are deficient.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Thornton, David Phillip. "The New Zealand National Environmental Standards for ambient air quality: analysis and modelling case study." Thesis, University of Canterbury. Geography, 2007. http://hdl.handle.net/10092/1501.
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Historically, the New Zealand rationale behind air quality management has been to adopt an effects-based approach based on environmental impacts. Generally, this method has been efficient in that it permitted emitters to decide how to minimise and mitigate impacts. However, to address the inconsistencies in air quality management across New Zealand born of this approach, and to permit measures designed to improve the working of the Resource Management Act (RMA), National Environmental Standards for Ambient Air Quality have been developed and implemented to establish consistent regulation and protection for all New Zealanders. The standards were gazetted in September 2004, for full implementation by 2013. This thesis explores the implementation of the National Environmental Standards for Ambient Air Quality, examining the philosophy behind the standards and associated strategies for dealing with air pollution management in New Zealand, and the international context for the development of appropriate tools to address air quality concerns. The research also provides an independent dispersion modelling assessment of the application of the Ministry for the Environment's initiative regarding sulphur dioxide in the Marsden Point airshed, Northland, utilising The Air Pollution Model (TAPM) for a period when heightened concentration values had been recorded. The key outcomes of the thesis are: (i) 99.9th percentile and maximum values for the simulated two-day modelling case study are within those stipulated by the air quality standards for sulphur dioxide; (ii) modelled concentrations associated with shipping within the airshed of interest contribute significantly to total modelled values; (iii) the chief obstruction to increased use of the prognostic modelling approach is that of the unsatisfactory availability and integrity of emission inventories; (iv) performing long-term high-resolution simulations with multiple point sources is prohibitive due to computational demands; (v) good quality monitoring will always be required; (vi) the standards have broad and far-reaching implications for resource managers, resource users and possibly the economy of individual regions and the country as a whole; (vii) the successful implementation of the National Environmental Standards for Ambient Air Quality in New Zealand will integrate a thorough understanding of modelling, measurements, meteorology and emissions.
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Small, Andrew Alexander. "The influence of air pollution on the transmission of Barley Yellow Dwarf Virus by Rhopalosiphum padi (L.)." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313997.
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Rakowsky, Ademar R. "Simulations of the sulphur chemistry of a convective cloud." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66090.
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Hunt, Gillian A. "Environmental modification of the responses of vicia faba to sulphur dioxide." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/12479.
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Ngeleka, Tholakele Prisca. "Sulphur dioxide capture under fluidized bed combustion conditions / Tholakele Prisca Ngeleka." Thesis, North-West University, 2005. http://hdl.handle.net/10394/1416.
Full textAbstract:
An investigation was undertaken to determine the feasibility of increasing the hydrogen
production rate by coupling the water gas shift (WGS) process to the hybrid sulphur process
(HyS). This investigation also involved the technical and economical analysis of the water gas
shift and the H2 separation by means of Pressure swing adsorption (PSA) process. A technical
analysis of the water gas shift reaction was determined under the operating conditions selected
on the basis of some information available in the literature. The high temperature system (HTS)
and low temperature system (LTS) reactors were assumed to be operated at temperatures of
350ºC and 200ºC, respectively. The operating pressure for both reactors was assumed to be 30
atmospheres. The H2 production rate of the partial oxidation (POX) and the WGS processes was
242T/D, which is approximately two times the amount produced by the HyS process alone. The
PSA was used for the purification process leading to a hydrogen product with a purity of
99.99%. From the total H2 produced by the POX and the WGS processes only 90 percent of H2
is recovered in the PSA. The unrecovered H2 leaves the PSA as a purge gas together with CO2
and traces of CH4, CO, and saturated H2O. The estimated capital cost of the WGS plant with
PSA is about US$50 million. The production cost is highly dependent on the cost of all of the
required raw materials and utilities involved. The production cost obtained was US $1.41/kg H2
based on the input cost of synthesis gas as produced by the POX process. In this case the
production cost of synthesis gas based on US $6/GJ for natural gas and US $0/Ton for oxygen
was estimated to be US $0.154/kg. By increasing the oxygen and natural gas cost, the
corresponding increase in synthesis gas has resulted in an increase in H2 production cost of US $1.84/kg.Thesis (M.Sc. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2006.
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Mansfield, Philippa Jane. "Interactions of atmospheric sulphur dioxide with fungal diseases of winter barley." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47554.
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Blackie, Douglas Sinclair. "Sulphur dioxide : high resolution UV photoabsorption cross sections at 198 K." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508327.
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Pilkington, Bridget Jane. "Phospholipid composition of Saccharomyces cerevisiae and Zygosaccharomyces bailii and their response to sulphur dioxide." Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234034.
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Dursun, Sukru. "The effects of sulphur pollution on soil fungi and decomposition of tree leaf litters." Thesis, Cardiff University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321745.
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Tomlinson, David. "Stability of catalytic plate reactors." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337374.
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Ansuategi, Alberto. "Economic growth and environmental quality : a critical assessment of the environmental Kuznets curve hypothesis." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326770.
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MacMillan, Douglas C. "Valuing the environmental benefits of reduced acid deposition in the semi-natural environment." Thesis, University of Stirling, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244698.
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McCormick, Brendan Thomas. "Measuring volcanic sulphur dioxide degassing with the satellite-based Ozone Monitoring Instrument." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648608.
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Hayer, Catherine S. L. "Observations of sulphur dioxide emissions from the Soufriere Hills Volcano, Montserrat, W.I." Thesis, University of Reading, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631704.
Full textAbstract:
The flux of sulphur dioxide (S02) gas has been used as an indicator of the eruptive activity and reservoir degassing of volcanoes around the globe and specifically during the eruption of Soufriere Hills Volcano on Montserrat, W.I., which has been semi-continuous since 1995. During this study, S02 emission rates measured using ground- and satellite-based instruments were used to evaluate the strengths and weaknesses of two ultraviolet instruments: the satellite-based Ozone Monitoring Instrument (OMI) and a ground-based Differential Optical Absorption Spectrometer (DOAS) instrument array, during two phases of lava extrusion in 2008-2010. An apparent increase in the amount of S02 observed by OMI during lava extrusion compared to quiescence was not observed by the DOAS array. This led to the conclusion that the volcanic S02 plume is located higher in the atmosphere during increased volcanic activity, as a result of a variety of volcanic processes, making it easier to observe from space than from the ground. Measurements from the satellite-based Infrared Atmospheric Sounding Instrument (IASI) show similar trends over temporally-averaged periods to OMI but IASI gives values of S02 emission about 600 tonnes/day lower.
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Wright, E. A. "The effects of sulphur dioxide and nitrogen dioxide, singly and in mixture, on the growth of birch trees." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372938.
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Citrone, Sharon Deborah. "The effects of sulphur dioxide and nitrogen dioxide on the relationship between Auchenorrhyncha species and their host plants." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47809.
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Macdonald, Anne Marie. "Sulphur dioxide oxidation in a rainband : effects of in-cloud hydrogen peroxide production." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55616.
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Wookey, Philip Andrew. "Effects of dry deposited sulphur dioxide on the decomposition of forest leaf litter." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328496.
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Kargiolaki, Hariklia. "The response of poplar clones to atmospheric pollution by ozone and sulphur dioxide." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253283.
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Bosac, Creana. "The impact of ozone and sulphur dioxide on reproductive development in oilseed rape." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306618.
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Dicey, M. "The effect of cold maceration with and without sulphur dioxide on pinot noir wine." Lincoln University, 1996. http://hdl.handle.net/10182/1057.
Full textAbstract:
The effects of varying levels of sulphur dioxide (SO₂) on the cold maceration process was investigated with Pinot noir (Vitis vinifera L.) wine. The effects of these varying levels on the wines composition and colour parameters were examined. Cold maceration is a technique whereby grapes are crushed and placed at low temperatures (4 - lO°C) in the presence 50 - 150 mgL⁻¹ SO₂. This process is believed to provide a medium for the extraction of water soluble phenolic compounds, rather than the alcoholic extraction employed in normal fermentations. The extraction of these phenolic compounds was monitored from the juice through to six months of bottle age. The changes were measured using both Spectrophotometric and High Performance Liquid Chromatographic (HPLC) procedures. Cold maceration wines were found to be not significantly different to the control wine in all compositional parameters other than titrateable acidity which was found to be less than the control for all the cold maceration wines. The unsulphured cold maceration wine was not significantly different from the control wine in any of the spectral measurements except natural degree of ionisation, in which it was higher, and total phenolics, in which it was lower. These results indicate that the cold maceration process alone does not alter the extraction of phenolic compounds. The HPLC analysis of the wine confirmed the spectral results indicating that their were no significant differences in the levels of extraction of anthocyanins. The sulphured cold maceration wines were significantly greater than the control in visible colour, colour density, total anthocyanins, natural degree of ionisation, ionised anthocyanins and total phenolics. These results followed similar patterns with wine ageing, at six months these wines were still significantly greater in all the measurements apart from natural degree of ionisation. The results for the sulphured cold maceration wines indicates that SO₂ is acting as a solvent for the extraction of phenolic compounds including anthocyanins. The 50 mgL⁻¹ SO₂ cold maceration wine had similar colour and phenolic content to the 100 mgL⁻¹ SO₂ cold maceration wine at bottling, at six months the 50 mgL⁻¹ SO₂ cold maceration wine still retained a similar colour to the 100 mgL⁻¹ SO₂ cold maceration wine but had vastly reduced anthocyanin content. This indicates that for the grapes utilised in this study the most appropriate level of addition at cold maceration would be 50 mgL⁻¹ of SO₂. With grapes of differing phenolic content the level of addition required will vary.
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Coetzee, Carien. "Oxygen and sulphur dioxide additions to Sauvignon blanc : effect on must and wine composition." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6733.
Full textAbstract:
Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2011.Includes bibliogaphy.
ENGLISH ABSTRACT: Sauvignon blanc wines have become increasingly popular in South Africa as it is a cultivar that can be easily manipulated in the vineyard and cellar to produce a range of wine styles. These wines are usually given aroma descriptors such as green pepper, grassy and asparagus; while other more tropical aromas include passion fruit and guava. These aromas are thought to be mainly caused by methoxypyrazines and volatile thiols. These compounds are known to be character impacting compounds of Sauvignon blanc and are present in the grapes in the aromatic form (methoxypyrazines) or as non‐aromatic precursors (thiols) that can be released by the yeast during fermentation. Other aroma compounds such as esters, higher alcohols, fatty acids and monoterpenes are compounds that could potentially influence the aroma bouquet of a wine significantly. These aroma compounds exist either as precursors in the grapes (monoterpenes) or arise due to yeast metabolism during fermentation (esters, higher alcohols, fatty acids) and often display fruity, floral and pleasant aromas. In the cellar, winemaking practices can be manipulated to a certain extent to achieve the desired wine style. Winemaking tools such as temperature, skin contact, pressing conditions, oxygen (O2), sulphur dioxide (SO2) and yeast strain are only a few factors influencing the outcome of a wine. In general, South African winemakers maintain a very reductive environment during Sauvignon blanc wine production by using inert gasses, thereby causing the production costs to increase. There is sufficient evidence to support the reductive handling of white wine, however there seems to be a lack of information as to why the must should be treated reductively before fermentation. The over all goal of this study was thus to investigate the effect of different O2 and SO2 additions to Sauvignon blanc must before settling, specifically focussing on the typical aroma compounds often found in these wines. Chapter 2 gives an overview of the oxidation reactions occurring in must (enzymatic oxidation) and wine (chemical oxidation). This chapter also reports the origin of the specific Sauvignon blanc aroma compounds and their reaction to different must and wine treatments with a focus on oxidation. Chapter 3 reports research results focussing on the effect of the different must treatments on the character impacting compounds of Sauvignon blanc wines, specifically the methoxypyrazines and the volatile thiols. The effect of the treatments on the polyphenols and glutathione content in the must and wine was also investigated. Oxidation in the absence of SO2 led to a decrease in glutathione and certain phenolic compounds in the must. In general, volatile thiols were protected against oxidation by SO2, even when O2 was present in the must. Methoxypyrazines concentrations were not significantly influenced by the treatments. Chapter 4 elucidates the effect of the treatments on other yeast and grape derived aroma compounds often found in Sauvignon blanc wines, such as the esters, higher alcohols, fatty acids and monoterpenes. In general, the effect of SO2 seemed to have the greatest influence on the produced aroma compounds. The results reported in this thesis could possibly change the way South African Sauvignon blanc musts are handled in future during the winemaking process. It is clear that O2 and SO2 management in the cellar is of critical importance for the winemaker to produce wines of high quality. Future work is important to fully understand the mechanisms and evolution of important aroma compounds of Sauvignon blanc wines during the winemaking process.
AFRIKAANSE OPSOMMING: Sauvignon blanc wyn aroma word gewoonlik beskryf met terme soos groen rissie, grasagtig en aspersie terwyl ander tropiese aromas soos grenadella en koejawel ook dikwels voorkom. Die manipulasie van Sauvignon blanc in die wingerd en in die kelder tydens wynmaak, gee die wynprodusent die vryheid om ‘n wye reeks wyn style te produseer. Dit maak Sauvignon blanc baie populêr in die Suid‐Afrikaanse wynindustrie. Die bogenoemde aromas word waargeneem in die wyn as gevolg van die teenwoordigheid van sekere aroma komponente genaamd metoksipirasiene en vlugtige tiole. Hierdie komponente lewer ‘n unieke bydrae tot die aroma samestelling van Sauvignon blanc wyne en kom voor in die druiwe in die aromatiese vorm (metoksipirasiene) of as nie‐aromatiese voorlopers (tiole) wat tydens alkoholiese fermentasie deur die gis vrygestel kan word. Komponente soos esters, hoër alkohole, vetsure en monoterpene kan ook ‘n potensiële bydra lewer tot die algehele aroma van Sauvignon blanc wyne en kom voor in die druiwe (monoterpene) of ontstaan as gevolg van gis metabolisme gedurende alkoholiese fermentasie (esters, hoër alkohole, vetsure). Hierdie geur komponente word dikwels beskryf as vrugtig, blomagtig en oor die algemeen aangenaam. Tydens wynmaak kan die wyn tot ‘n mate gemanipuleer word om ‘n spesifieke wynstyl te bekom. Hulpmiddels soos temperatuur, dopkontak, pers omstandighede, suurstof (O2), swawel dioksied (SO2) en gisras is slegs ‘n paar faktore wat die algemene uitkoms van ‘n wyn kan beïnvloed. Oor die algemeen word Sauvignon blanc in Suid‐Afrika baie reduktief behandel tydens wynbereiding. Dit vereis sekere hulpmiddels, soos die gebruik van inerte gas, wat die produksiekoste dikwels verhoog. Navorsing ondersteun die reduktiewe behandeling van wit wyn, maar dit wil voorkom asof daar ‘n tekort aan navorsing is wat die reduktiewe behandeling van die sap voor fermentasie regverdig. Die algemene doel van die studie is dus om die effek van verskillende O2 en SO2 byvoegings tot Sauvignon blanc sap (voor afsak) te ondersoek met die fokus op die tipiese aroma komponente wat in die wyn voorkom. Hoofstuk 2 lewer ‘n algemene oorsig van die tipes oksidasie reaksies wat voorkom in sap (ensiematiese oksidasie) en wyn (chemiese oksidasie). Spesifieke Sauvignon blanc aroma komponente word ook ondersoek in terme van die oorsprong van die komponente asook die reaksie wat plaasvind met verskillende mos en wyn behandelings, met ‘n fokus op oksidasie. In hoofstuk 3 word die effek van die verskillende mos behandelings op tipiese Sauvignon blanc aroma komponente, spesifiek metoksipirasiene en vlugtige tiole, ondersoek. Die effek van die behandelings op die polifenole en glutatioon inhoud in die mos en wyn word ook gerapporteer. Oksidasie van die sap in die afwesigheid van SO2, het ‘n afname in glutatioon en sekere polifenol konsentrasies veroorsaak. Dit wil voorkom asof die produksie van vlugtige tiole oor die algemeen beskerm word teen oksidasie indien daar genoegsame SO2 teenwoordig is. Hierdie effek word ondervind selfs as die sap met suursof versadig word. Die effek van die behandelings op die konsentrasies van metoksipirasiene was nie beduidend nie. Hoofstuk 4 rapporteer die effek van die behandelings op ander aroma komponente soos esters, hoër alkohole, vetsure en monoterpene. Oor die algemeen wil dit voorkom asof die effek van SO2 beduidend was en waarskynlik die grootste invloed op die produksie van hierdie aroma komponente het. Na aanleiding van die resultate bevind in hierdie tesis, is daar ‘n moontlikheid dat die manier waarop Sauvignon blanc wyne geproduseer word in Suid‐Afrika, moontlik kan verander in die toekoms. Vir die wynmaker om hoë kwaliteit Sauvignon blanc wyne te produseer, is O2 en SO2 bestuur in die kelder van kardinale belang. Verdere navorsing moet steeds gedoen word om die meganisme en evolusie van belangrike aroma komponente in Sauvignon blanc wyne tydens die wynmaakproses, ten volle te verstaan.