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Image Analytic Tools for Optical Coherence Tomography Tissue Characterization and Robust LearningHuang, Ziyi January 2023 (has links)
The computer-aided analysis is poised to play an increasingly prominent role in medicine and healthcare. Benefiting from the increasing computing power, various machine learning frameworks have been developed in the biomedical field, bringing significant improvements in real-world clinical applications. However, for many diseases, the development of these life-supporting algorithms is still in its infancy. To bridge this gap:
This thesis is dedicated to the development of efficient algorithms for better image intervention and addressing data quality challenges in machine learning algorithms to provide direct guidance for real-world clinical applications.
With the above goals, three topics are explored in depth. First, we develop a novel tissue analysis framework for cardiac substrate identification and tissue heterogeneity assessment. In particular, we creatively used model uncertainty to measure tissue structure information, offering a means of extracting the tissue heterogeneity information in a non-invasive way for real-time imaging and processing.
The tissue analysis framework in the first aim is based on the fully supervised technique, which relies heavily on the availability of large-scale datasets with accurate annotations. Such high-quality datasets are extremely time-consuming to acquire, especially for biomedical segmentation tasks. To lessen the need for the labeling process, we further develop three weakly supervised learning frameworks to address data and labeling challenges caused by limited data resources.
Finally, we develop an in-vivo tissue analysis framework on cardiac datasets, aiming to provide real-time guidance for clinical ablation procedures. Our models could contribute to the improvement of ablation treatment by identifying the ablation targets and avoiding critical structures within the hearts.
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Applications of Soft ComputingTiwari, A., Knowles, J., Avineri, E., Dahal, Keshav P., Roy, R. January 2006 (has links)
No
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Design and development of an external cavity diode laser for laser cooling and spectroscopy applicationsNyamuda, Gibson Peter 12 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2006. / External cavity diode lasers are used increasingly as sources of light in applications ranging from
industrial photonic systems to basic laboratory research on the interaction of light and atoms.
External cavity diode lasers offer more stable output frequency and narrow spectral bandwidth
than the typical free-running diode lasers. These characteristics are achieved by exploiting the
sensitivity of diode lasers to external optical feedback. In this study the design and development
of an external cavity diode laser system for future applications in spectroscopy and laser cooling
of rubidium atoms is presented. The external cavity diode laser including mechanical components
and control electronics of the system is developed from basic components. The system uses frequency
selective optical feedback from a diffraction grating in a Littrow configuration to provide
collimated, narrow-band, frequency tunable light near 780 nm. The external cavity diode laser is
designed to increase the mode-hop-free frequency tuning range, and allow accurate frequency tuning
and stabilisation. A low-noise current source and a temperature controller for thermal stability
were developed as part of the system since the output frequency changes with temperature and
current. The temperature controller is optimised experimentally for the thermal characteristics of
the external cavity. An electronic sidelock servo circuit for frequency locking of the external cavity
diode laser to an external reference for long term frequency stabilisation is proposed and discussed.
The servo circuit electrically controls the grating tilt and the current through the diode laser in
order to lock the frequency of the diode laser. The external cavity diode laser is optimised and
characterised near 780 nm. Results obtained in this study indicate that the external cavity diode
laser is suitable for future applications in spectroscopy and laser cooling of neutral rubidium atoms.
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Response of NaI(T1) detectors in geophysical applicationsTitus, Nortin P. 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2005. / Some digitised pages may appear illegible due to the condition of the original hard copy. / ENGLISH ABSTRACT: Airborne gamma-ray spectrometry is used for exploration and environmental monitoring over large areas. Such datasets of 7-ray are acquired using large 16l NaI(T1) detector
crystals mounted in an aircraft. The response of these detectors to naturally occurring
radioactive isotopes is a function of detector volume, efficiency and resolution. This response
is modelled using the Monte Carlo method. A photon-electron transport computer
code, NIPET, is written to calculate the intrinsic efficiency and photofraction of these
large prismatic crystals. The intrinsic efficiency indicates the number of incident photons
that interact in some way with the detector resulting in a deposition of energy in the
crystal. The photofraction, on the other hand, indicates how many of these photons that
impinge on the detector are actually recorded with their full initial energy. This study
presents explicity calculated photofraction values for 16l NaI(Tl) crystals. Comparison of
these new values, calculated with this computer program, with that of published values
for small 3" x 3" crystals shows good agreement. However, for large crystals, the calculated
values differ from those in the literature by almost 15%. The study also finds that
for the gamma-ray energy range between 0.2 - 3.0 MeV, these detectors have an intrinsic
efficiency above 90%, whereas the photofraction values range from 80% for low energy
photons to above 40% for high energy photons in the case of large crystals. / AFRIKAANSE OPSOMMING: Lug gamma-straal spektroskopie is nuttig vir eksplorasie en omgewings ondersoeke oor
groot areas. Metings word tipies gedoen met 16l NaI(T1) detektors wat monteer is in ’n
vliegtuig. Die respons van hierdie detektors ten opsigte van natuurlike radioaktiewe isotope
is ’n funksie van detektorvolume, doeltreffendheid en oplosvermoë. Hierdie respons
word gemodeleer deur gebruik te maak van ’n Monte Carlo tegniek. ’n Rekenaarprogram,
NIPET, is geskryf om die intrinsieke doeltreffendheid en fotofraksie vir hierdie groot prismatiese
kristalle te bereken. Die intrinsieke doeltreffendheid dui die breukdeel van die
invallende fotone aan wat ’n interaksie ondergaan binne die detektor kristal en sodoende
energie deponeer. Die fotofraksie, daarenteen, dui die breukdeel invallende fotone aan
wat absorbeer word deur die kristal met hul voile invallende energie. In hierdie tesis
word eksplisiete fotofraksiewaardes vir 16l NaI(T1) kristale bereken. Goeie ooreenstemming
word gevind tussen fotofraksie waardes bereken met hierdie program en die waardes
gepubliseer in die literatuur vir klein 3" x 3" kristalle. Vir groter kristalle is daar egter
swakker ooreenstemming. Berekende fotofraksie waardes verskil met 15% van die waardes
in die literatuur. Daar word ook bevind dat vir gamma-energie tussen 0.2 - 3.0 MeV, die
intrinsieke doeltreffendheid vir hierdie tipe detektors bo 90% is en dat fotofraksiewaardes
wissel tussen 80% vir lae energie tot bo 40% vir hoë foton energie.
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Influence of oxygen addition on the phenolic composition of red wineGeldenhuys, Lorraine 12 1900 (has links)
Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Tannins and colour components in red wine are important quality parameters. These factors can
be manipulated in the vineyard by grape growing techniques or in the cellar by different winemaking
practices. Grape seeds make a significant contribution to tannin concentration in wine
when compared to those from the skins and pulp. Tannins contribute to the ageing potential,
organoleptic properties and stabilisation of red wine colour. The colour of a red wine is also
influenced by malolactic fermentation, the biological process that transforms malic acid into
lactic acid which normally leads to an increase in pH. The subsequent change in pH alters the
anthocyanin equilibrium, the primary colour components in red wine. Oxygen contributes to the
polymerisation of anthocyanins over time to form more stable pigments that are less sensitive to
pH fluctuations and sulphur dioxide bleaching. Limited research has been done on the use of
oxygen after alcoholic fermentation and the impact it has on the phenolic composition of red
wines. Similarly, only a few studies have examined the impact of either the addition or removal
of seeds to the phenolic composition of a red wine in combination with oxygen addition.
Additionally, little published data seems to exist on the effect of different pHs on red wine’s
phenolic and colour development after oxygen addition.
In our results we have shown that it is possible to stabilise wine colour by adding
supplementary seeds before alcoholic fermentation. This led to an increase in colour intensity in
certain cases. Some red wines produced without seeds had significantly lower colour intensities.
This clearly suggests that catechins and proanthocyanidins are extracted from seeds and
contribute to wine colour as they combine with other pigments to stabilise wine colour.
Spectrophotometric and HPLC analyses have shown that the total phenolic content increased
with seed concentration. However, we have observed that a wine may possibly become
saturated with phenols when supplementary seeds are added. Anthocyanin concentrations
often decreased when oxygen was added, while polymeric phenols and polymeric pigments
sometimes increased.
When applying different oxygen dosages to a red wine on commercial scale with microoxygenation,
it was found that monomeric anthocyanins decreased as more oxygen was added
and this decrease in anthocyanins led to the formation of stable polymeric pigments. This
was reflected in the significant increase in colour intensity for the wines receiving oxygen. Small
differences were detected in the total phenol and tannin concentration for the control and
oxygenated wines. However, some of these phenolic and colour differences disappeared
during subsequent ageing of the wine.
When making wines of different initial pHs, we observed that the colour density decreased
as the pH increased. The application of oxygen reduced the decrease in colour during MLF,
especially at a lower pH. The addition of oxygen did not result in significantly different polymeric
pigment concentrations in the various pH treatments, although the results could have been
different if the wines were aged. However, pH differences in the range between 3.4 and 4.0 did
not significantly influence the phenol composition of the wines under our conditions. This study
led to a better understanding on the effect of oxygen additions under different conditions on red
wine's phenolic and colour composition. / AFRIKAANSE OPSOMMING: Tanniene en kleur komponente teenwoordig in rooiwyn is belangrike kwaliteit parameters.
Hierdie faktore wat wynkwaliteit beïnvloed kan gemanipuleer word in die wingerd deur verskeie
verbouingstegnieke toe te pas en in die kelder deur die toepassing van verskillende
wynbereidingsmetodes. Die bydrae van sade tot die finale tannienkonsentrasie in rooiwyn is
groot in vergelyking met dié van die pulp en doppe. Tanniene dra by tot die verouderingspotensiaal,
organoleptiese eienskappe en die stabilisasie van die wynkleur. Die kleur van ‘n rooi
wyn word ook beïnvloed deur appelmelksuurgisting (AMG), die biologiese proses wat appelsuur
omskakel na melksuur en ‘n gevolglike toename in die pH van die wyn veroorsaak. Hierdie
verandering in die pH van die wyn beïnvloed die antosianien ewewig, die primêre kleur
komponente teenwoordig in rooiwyn. Suurstof dra by tot die polimerisasie van antosianiene oor
tyd om meer stabiele kleur pigmente te vorm met ‘n hoër kleurintensiteit wat minder sensitief is
teenoor pH veranderinge en die bleikingseffek van swaweldioksied. Beperkte navorsing is
gedoen op die gebruik van suurstof na alkoholiese gisting en die impak daarvan op die
fenoliese samestelling van ‘n rooiwyn. Slegs ‘n paar studies het die invloed van die verwydering
of byvoeging van sade in kombinasie met suurstoftoediening op ‘n rooiwyn se fenoliese
samestelling ondersoek. Dit wil voorkom of beperkte gepubliseerde data beskikbaar is oor die
effek wat verskillende pH’s het op rooi wyn se fenoliese en kleurontwikkeling na suurstof
byvoeging.
Ons resultate het aangedui dat dit wel moontlik is om in sekere gevalle die kleur van ‘n
rooiwyn te stabiliseer deur addisionele sade by te voeg voor alkoholiese fermentasie. Hierdie
byvoeging het ‘n toename in kleurintensiteit tot gevolg gehad. Sekere wyne wat gemaak is
sonder sade het ‘n kenmerkend laer kleur intensiteit gehad. Hierdie bevinding is ‘n duidelike
bewys dat katesjiene en prosianidiene geëkstraheer word vanuit die sade en bydra tot wynkleur
deurdat hulle met ander pigmente verbind om die kleur sodoende te stabiliseer.
Spektrofotometriese en hoë druk vloeistof chromatografie (HDVC) analises het gewys dat die
totale fenoliese konsentrasie neem toe met ‘n toename in saad konsentrasie. Daar is egter
waargeneem dat ‘n wyn moontlik versadig kan raak met fenole wanneer addisionele sade
bygevoeg word. Antosianien konsentrasies het meestal afgeneem wanneer suurstof bygevoeg
is, maar polimeriese fenole en polimeriese pigmente het partykeer toegeneem.
Met die toediening van verskillende suurstof dosisse tot ‘n rooiwyn op kommersiële skaal
het ons bevind dat monomeriese antosianiene afneem wanneer meer suurstof bygevoeg word.
Hierdie afname in antosianiene het egter gelei tot die vorming van stabiele polimeriese
pigmente. Dié bevinding was gereflekteer in die toename in kleurintensiteit van wyne wat met
suurstof behandel is. Klein verskille was waargeneem vir die totale fenol en tannien
konsentrasies tussen die kontrole en wyne behandel met suurstof. Sekere van hierdie fenoliese
kleur verskille het egter afgeneem tydens die daaropvolgende veroudering van die wyne.
Wyne wat gemaak is met verskillende aanvanklike pH’s se kleurintensiteit neem af soos
die pH toeneem. Die toediening van suurstof het die kleurverlies tydens AMG verminder, veral
by ‘n laer pH. Die toediening van suurstof het nie verskillende polimeriese pigment
konsentrasies by verskillende pH’s veroorsaak nie, maar ‘n verskil kon moontlik waargeneem
word indien die wyne verouder was. pH verskille tussen 3.4 en 4.0 het egter nie die fenoliese
samestelling van die wyne onder ons omstandighede beduidend beïnvloed nie. Hierdie studie
het gelei tot meer kennis oor die effek van suurstoftoedienings onder verskillende kondisies op
rooiwyn se fenoliese en kleursamestelling.
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The development of polysaccharide degrading wine yeast strainsLouw, Campbell (Campbell Trout) 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The polysaccharides that are present in wine originate from the grapes, the fungi that
grow on the grapes and from other microorganisms that come into contact with the
must during winemaking. The grape-derived polysaccharides of most concern in
winemaking are pectin, glucan and xylan that can be enzymatically degraded by
pectinases, glucanases and xylanases, respectively. These are the main structural
polysaccharides of the cell wall of the grape cell. Degradation of the cell walls will
result in the separation and rupture of the grape cells, and cell wall-bound
compounds will be released into the must. Treating the must with pectinase and
macerating enzyme preparations can result in an increase in free-flow juice, an
improvement in must clarification and filtration, and an increased extraction of
phenols and tannins. The tannins that are extracted polymerise with anthocyanins in
red wine during ageing, resulting in increased colour intensity and stability. Wine
aroma is also influenced by enzyme treatment. The degradation of the cell wall
contributes to the release of glycosidically-bound terpene or alcohol precursors from
the berries. The hydrolysis of these precursors during fermentation can result in an
improvement in aroma. It can thus be seen that it is possible to improve wine quality
and processing by supplementing the endogenous enzymes that are present in the
fermentation with commercial enzyme preparations. Commercial enzymes are
typically crude fungal preparations.
The majority of commercial pectinase and glucanase preparations are derived
from Aspergillus and Trichoderma, respectively. Since the endogenous
polysaccharase activity of Saccharomyces cerevisiae is very limited, the
heterologous expression of specific polysaccharase genes in an industrial yeast
strain can improve the winemaking process, resulting in a higher quality wine without
the addition of expensive commercial enzyme preparations. Since only the desired
enzymes are secreted by the recombinant strain, there will be no undesired sideactivities,
which can be detrimental to wine quality. Several pectinase-, glucanaseand
xylanase-encoding genes, cloned from a variety of organisms, have been
expressed successfully in laboratory strains of S. cerevisiae. Attempts have also
been made to construct industrial wine yeast strains that express these
polysaccharase genes and secrete the encoded enzymes. Fermentation with some
of these strains resulted in a decrease in total phenolics and turbidity, an increase in
juice extraction, and alterations in the colour and aromatic profile of the resulting
wines.
In this study, four polysaccharide-degrading, recombinant wine yeast strains were
constructed. The endo-β-1,4-xylanase gene, XYN2, and the endo-β-1,4-glucanase
gene, end1, were previously cloned from the soft rot fungus Trichoderma reesei and
the rumen bacterium Butyrivibrio fibrisolvens, respectively. These genes were
subcloned into different expression cassettes which were used to construct the four
integration plasmids. The recombinant plasmids contained the following gene
cassettes: TEF1P-XYN2-ADH2T (plasmid pDLG29) ADH1P- MFα1S -end1-TRP5T (plasmid pDLG30) ADH1P-MFα1S-end1-TRP5T and
ADH2P-XYN2-ADH2T (plasmid pDLG33), ADH1P-MFα1S-end1-TRP5T and YG100PXYN2-
ADH2T (plasmid pDLG39). These four plasmids were then separately
integrated into the ILV2 locus of the commercial wine yeast strain S. cerevisiae
VIN13. Wine was made with the four strains constructed in this study, a pectolytic
strain, VIN13[pPPK], a glucanase- and xylanase-secreting strain, VIN13[pEX], an
untransformed VIN13 strain, and an untransformed strain with the addition of the
commercial enzyme preparation Rapidase EX Colour. Microvinification experiments
were carried out on Pinot noir, Ruby Cabernet and Muscat d’Alexandria wines.
Fermentation with the polysaccharide-degrading strains resulted in significant
improvements in juice extraction, colour intensity and stability, and in alterations in
the aromatic profiles of the wines produced.
Subject to the approval by the regulatory authorities and eventual consumer
acceptance of the use of genetically modified organisms (GMOs) in fermented foods
and beverages, it might be required that the GM status of the yeast that is used
appears on the label. Currently, there is no robust technique available with which the
use of GM yeast can be revealed in a finished wine because the yeast cells and their
DNA are removed from or denatured in the wine during filtration and processing. One
way with which the undeclared use of a GM yeast in winemaking could be exposed
would be to compare the chemical profile of a suspect wine with that of non-GM wine.
In order to explore this concept further, a secondary aim of this study was to
investigate whether Fourier Transformation Infra Red (FT-IR) spectroscopy coupled
with multivariate data analysis could distinguish between wines fermented with
transgenic and non-transgenic yeast strains, or between wines fermented with
different transgenic strains. The results showed that this method could be used to
classify wines fermented with different yeast strains if fermentation with the strain
resulted in a unique chemical profile in the resulting wine. This was a preliminary
study and these findings were summarised as an addendum to the thesis. / AFRIKAANSE OPSOMMING: Die polisakkariede wat in wyn teenwoordig is, is afkomstig van die druiwe, die
swamme wat op die druiwe groei en vanaf ander mikroörganismes wat tydens die
wynmaakproses met die mos in aanraking kom. Die belangrikste druifpolisakkariede
in wynbereiding is pektien, glukaan en xilaan, wat onderskeidelik deur pektinases,
glukanases en xilanases afgebreek kan word. Hierdie is die vernaamste strukturele
polisakkariede van ‘n druifsel se selwand. Die afbreking van die selwande veroorsaak
dat die druifselle skei en skeur, met die gevolg dat die selwandgebonde verbindings
in die mos vrygelaat word. Die behandeling van die mos met pektinase en
versappingsensiempreparate kan tot ʼn toename in vry-afloopsap lei, sowel as ʼn
verbetering in mosverheldering en -filtrasie en ʼn verhoogde ekstraksie van fenole en
tanniene. Die tanniene wat geëkstraheer word, polimeriseer in rooiwyn tydens
veroudering, en dit lei tot verhoogde kleurintensiteit en -stabiliteit. Wynaroma word
ook deur ensiembehandeling beïnvloed. Die afbreking van die druifselwand dra by tot
die vrylating van glikosidiesgebonde terpeen- en alkoholvoorlopers uit die korrels. Die
hidrolise van hierdie voorlopers tydens gisting kan lei tot ʼn verbetering van die
aroma. Dit is dus duidelik dat dit moontlik is om wynkwaliteit en wynbereiding te
verbeter deur die endogene ensieme wat in die gisting teenwoordig is met
kommersiële ensiempreparate te supplementeer.
Kommersiële ensiempreparate is tipies ongesuiwerde swampreparate. Die
meerderheid kommersiële pektinase- en glukanasepreparate word onderskeidelik
vanaf Aspergillus en Trichoderma verkry. Aangesien die endogene polisakkaraseaktiwiteit
van Saccharomyces cerevisiae baie beperk is, kan die heteroloë uitdrukking
van spesifieke polisakkarase-gene in ʼn industriële gisras die wynbereidingsproses
verbeter en lei tot ʼn hoër kwaliteit wyn sonder die byvoeging van duur kommersiële
ensiempreparate. Omdat die verkose ensieme deur die rekombinante ras uitgeskei
word, sal daar geen ongewenste newe-effekte teenwoordig wees wat ʼn nadelige
effek op wynkwaliteit kan hê nie. Verskeie mikrobiese gene wat vir pektinases,
glukanases en xilanases kodeer, is reeds voorheen uit ‘n wye verskeidenheid van
organismes gekloneer en suksesvol in laboratoriumrasse van S. cerevisiae uitgedruk.
Pogings is ook aangewend om industriële wyngisrasse te konstrueer wat hierdie
polisakkarasegene uitdruk en hul enkodeerde ensieme uitskei. Gisting met sommige
van hierdie rekombinante gisrasse het gelei tot ʼn afname in totale fenoliese
verbindings en troebelheid, ʼn verhoging in sapekstraksie, en veranderings in die
kleur en aromatiese profiel van die gevolglike wyne.
In hierdie studie is vier polisakkaried-afbrekende, rekombinante wyngisrasse
gekonstrueer. Die endo-β-1,4-xilanasegeen, XYN2, en die endo-β-1,4-
glukanasegeen, end1, is voorheen reeds onderskeidelik vanaf die sagte vrotswam,
Trichoderma reesei, en die rumenbakterium, Butyrivibrio fibrisolvens, gekloneer.
Hierdie gene is in vier integrasieplasmiede in verskillende ekspressiekassette
gesubkloneer. Die plasmiede het die volgende geenkassette bevat: TEF1P-XYN2-
ADH2T (plasmied pDLG29) ADH1P- MFα1S -end1-TRP5T (plasmied pDLG30) ADH1PMFα1S-
end1-TRP5T and ADH2P-XYN2-ADH2T (plasmied pDLG33), ADH1P-MFα1S end1-TRP5T and YG100P-XYN2-ADH2T (plasmied pDLG39). Hierdie vier plasmiede
is toe afsonderlik in die ILV2-lokus van die kommersiële wyngisras, S. cerevisiae VIN
13, geïntegreer. Wyn is met hierdie vier gekonstrueerde gisrasse gemaak, die
pektolitiese gisras, VIN13[pPPK], die glukanase- en xilanase-afskeidende gisras,
VIN13[pEX], die ongetransformeerde VIN13-ras, en met ʼn ongetransformeerde
VIN13 gis waarby die kommersiële ensiempreparaat, Rapidase EX Colour, bygevoeg
is. Mikro-wynbereidingseksperimente is op Pinot noir-, Ruby Cabernet- en Muscat
D’Alexandria wyne uitgevoer. Gisting met die polisakkaried-afbrekende gisrasse het
gelei tot ʼn noemenswaardige verbetering in sapekstraksie, kleurintensiteit en
kleurstabiliteit, asook in veranderinge in die aromatiese profiele van die
geproduseerde wyne.
Indien die gebruik van geneties gemodifiseerde organismes (GMOs) in
gefermenteerde voedsel en drank deur die reguleringsowerhede goedgekeur en
uiteindelik deur die verbruiker aanvaar sou word, sou dit vereis kon word dat die GMstatus
van die wyngisgis op die etiket van die wynbottel aangebring word. Verpligte
etikettering van GM-wyn sal metodes vereis waarmee die ‘nalentskap’ van GMgisselle
in die finale produk geïdentifiseer en gemoniteer kan word. Tans is daar
geen robuuste tegnieke beskikbaar waarmee die gebruik van GM-giste openbaar kan
word nie, aangesien die gisselle en hul DNA tydens filtrasie en prosessering
verwyder word. Een wyse waarop die onverklaarde gebruik van ‘n GM-gis in
wynbereiding blootgestel sou kno word, is om die chemiese profiel van die verdagte
wyn met dié van ‘n nie-GM-wyn te vergelyk. Ten einde hierdie konsep verder te
ondersoek was ‘n sekondêre doelwit van hierdie studie om te bepaal of FT-IR
(Fourier-transformasie-infrarooi) spektroskopie tesame met meervariante dataanalise
gebruik kan word om te onderskei tussen wyne wat met transgeniese en nietransgeniese
gisrasse gegis is, of tussen wyne wat met verskillende transgeniese
rasse gegis is. Die resultate het aangedui dat hierdie metode gebruik kan word om
wyne wat met verskillende gisrasse gegis is, te klassifiseer indien die betrokke gisras
ʼn unieke chemiese profiel in die uiteindelike wyn veroorsaak het. Dit was egter ʼn
voorlopige ondersoek en is as ʼn byvoegsel tot die tesis geskryf.
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Converged IP-over-standard ethernet progress control networks for hydrocarbon process automation applications controllersAlmadi, Soloman Moses January 2011 (has links)
The maturity level of Internet Protocol (IP) and the emergence of standard Ethernet interfaces of Hydrocarbon Process Automation Application (HPAA) present a real opportunity to combine independent industrial applications onto an integrated IP based network platform. Quality of Service (QoS) for IP over Ethernet has the strength to regulate traffic mix and support timely delivery. The combinations of these technologies lend themselves to provide a platform to support HPAA applications across Local Area Network (LAN) and Wide Area Network (WAN) networks. HPAA systems are composed of sensors, actuators, and logic solvers networked together to form independent control system network platforms. They support hydrocarbon plants operating under critical conditions that — if not controlled — could become dangerous to people, assets and the environment. This demands high speed networking which is triggered by the need to capture data with higher frequency rate at a finer granularity. Nevertheless, existing HPAA network infrastructure is based on unique autonomous systems, which has resulted in multiple, parallel and separate networks with limited interconnectivity supporting different functions. This created increased complexity in integrating various applications and resulted higher costs in the technology life cycle total ownership. To date, the concept of consolidating HPAA into a converged IP network over standard Ethernet has not yet been explored. This research aims to explore and develop the HPAA Process Control Systems (PCS) in a Converged Internet Protocol (CIP) using experimental and simulated networks case studies. Results from experimental and simulation work showed encouraging outcomes and provided a good argument for supporting the co-existence of HPAA and non-HPAA applications taking into consideration timeliness and reliability requirements. This was achieved by invoking priority based scheduling with the highest priority being awarded to PCS among other supported services such as voice, multimedia streams and other applications. HPAA can benefit from utilizing CIP over Ethernet by reducing the number of interdependent HPAA PCS networks to a single uniform and standard network. In addition, this integrated infrastructure offers a platform for additional support services such as multimedia streaming, voice, and data. This network‐based model manifests itself to be integrated with remote control system platform capabilities at the end user's desktop independent of space and time resulting in the concept of plant virtualization.
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Modélisation du rayonnement thermique en immersion de volume / Numerical radiative transfer using an immerse volume methodSchmid, Quentin 14 December 2016 (has links)
Dans le cadre des procédés de chauffage et de trempe réalisés lors d’opération de mise en forme des matériaux, le rayonnement thermique joue un rôle prépondérant. Lors de l’élaboration de modèles numériques permettant la simulation de ces procédés, il est donc nécessaire de disposer d’outils performants pour simuler ce phénomène.La simulation numérique de tels procédés soulèvent de nombreuses problématiques, comme la représentation d’un environnement complexe impliquant plusieurs composants (pièces, bruleurs, buses d’injection, parois), la gestion des divers phénomènes physiques couplés (écoulement, transfert thermiques, ébullition, rayonnement). Dans cette perspective, les méthodes dites « d’immersion », permettant un traitement généraliste de ces divers problèmes, rencontrent depuis quelques années un intérêt grandissant dans la communauté scientifique.C’est dans ce contexte que s’inscrit le projet Thost, au sein duquel est réalisée cette thèse. L’objectif est donc de développer des outils pour la modélisation du rayonnement dans le contexte d’immersion de volume propre au logiciel Thost. Deux approches sont développées : l’une consistant en l’adaptation d’une méthode existante au contexte de l’immersion de volume, l’autre explorant l’élaboration d’une formulation pour un modèle particulier de rayonnement. Les outils développés sont ensuite mis à l’épreuve sur des simulations de cas industriels fournis par nos partenaires. / For heating and quenching operations occurring during material forming processes, thermal radiation is the the predominant physical phenomenon. Hence, when one tries to simulate such processes, it is important to have at disposal powerful tools for the numerical modelling of thermal radiation.The numerical simulation of these processes often rises numerous problems and questions, as the representation of a complex environment, involving several components ( ingots, burners, nozzles, walls), to deal with different coupled physical phenomena ( flow, heat transfer, boiling, thermal radiation). In this regard, some “immersed” numerical methods, allows a generalist treatment of these different problems, have gained popularity and drag interest of the scientific community in the recent years.The Thost project, aiming to produce a software for heat transfer during material forming processes, fits in the framework, and this PhD is part of this project. The goal is therefore to design tools for numerical modelling of thermal radiation within the immersed volume method of the Thost software. Two approaches are presented: one consisting in the adaptation of an existing method to the context of the immersed volume method, another concerning the development of a formulation for a specific model of radiation. These methods are then tested on industrial applications provided by our partners.
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Metodologia para avaliação e otimização de motores elétricos de indução trifásicos visando a conservação de energia em aplicações industriais / Methodology for evaluation and optimization of three-phase induction motors to promote the conservation of energy in industrial applications.Ramos, Mario Cesar do Espirito Santo 29 October 2009 (has links)
Esta tese apresenta uma metodologia específica para a quantificação das perdas energéticas em motores elétricos de indução trifásicos com rotor em gaiola, por meio da determinação indireta do rendimento nas condições de funcionamento a plena carga. A referida metodologia, denominada MHmit, foi desenvolvida em ambientes industriais, particularmente no segmento alimentício, contando também com a colaboração do Laboratório de Máquinas Elétricas do Instituto de Eletrotécnica e Energia da Universidade de São Paulo no tocante a disponibilização dos ensaios de vários motores de indução trifásicos com rotor em gaiola ao longo de vários anos de prestação de serviços. Esses ensaios foram de extrema importância para a validação da metodologia apresentada. Sendo o motor elétrico um equipamento de uso final de forte presença industrial, é passível de substituição por tecnologias mais eficientes mediante a realização de estudos de eficiência energética. Os diagnósticos energéticos em sistemas motrizes beneficiam as indústrias por meio da diminuição dos custos com energia elétrica, tanto pela redução de demanda, quanto pela redução do consumo. Porém, para o desenvolvimento desta metodologia foi necessária a avaliação de estudos realizados por empresas prestadoras de serviços na área de conservação de energia elétrica. Essas empresas foram selecionadas a partir da averiguação da satisfação do cliente quanto aos serviços prestados e resultados obtidos após a substituição dos motores. Por meio da análise de 266 casos, verificaram-se os problemas encontrados por essas empresas antes, durante e após a substituição dos motores elétricos do tipo padrão por de alto rendimento. Em alguns casos, a substituição de um motor antigo do tipo padrão por um motor novo do tipo alto rendimento resultou num aumento do consumo de energia elétrica, fato este totalmente controverso quando se espera uma economia de 2 a 6% proveniente desta mudança de tecnologias, de acordo com Eletrobrás e NEMA MG 1. A metodologia MHmit desenvolvida neste trabalho contempla esta situação. As principais metodologias atualmente utilizadas na realização de estudos para substituição de motores elétricos dos tipos padrão por alto rendimento foram analisadas e apresentadas neste trabalho. Dentre elas, a metodologia convencional, que utiliza curvas de motores elétricos para a determinação do rendimento, a metodologia que utiliza o programa denominado BD Motor, desenvolvido pelo Centro de Pesquisas em Energia Elétrica da Eletrobrás, a VII metodologia que utiliza o programa Mark IV, desenvolvido por pesquisadores da Universidade Federal de Itajubá, em parceria com o Procel / Eletrobrás e o software Motor Master, desenvolvido pelo Departamento de Energia Norte-Americano (DoE). Todos esses programas estão disponíveis gratuitamente para download no site do Procel Info / Eletrobrás - www.procelinfo.com.br. A metodologia MHmit, desenvolvida neste trabalho, apresentou desvios percentuais satisfatórios (10,12%) entre os valores previstos (durante as simulações com o aplicativo MHmit) e reais (por meio da verificação da real economia de energia elétrica proporcionada após a substituição do novo motor) das metodologias em estudo. Estas, não contemplam dados de parâmetros de motores antigos, dificultando a obtenção de um valor verdadeiro do rendimento do motor em funcionamento, pois muitas vezes este já sofreu reparos, rebobinagens e curtos-circuitos. Os 86 estudos de caso realizados para a validação desta metodologia (motores com potências de 7,5 a 125 cv) mostraram diferenças significativas entre os valores previstos pelas metodologias atuais e a metodologia desenvolvida MHmit. / This thesis presents a specific methodology to quantify the energy loss in three-phase induction electric motors with cage rotor, by indirect determination of efficiency under operation conditions at full load. This methodology, named MHmit, was developed in industrial environments, particularly in textile and food sectors, relying on the collaboration of the machines laboratory of the Institute of Electrotechnics and Energy, University of São Paulo on the availability of tests in several three-phase induction motors with cage rotor over several years under the laboratory service. These essays were extremely important to validate the presented methodology. Once the electric motor is an equipment of final use strongly present in industry, it is subject to replacement by more efficient technologies by carrying out energy efficiency studies. Energy Diagnosis in electric motors aims to provide the client with a decrease in electric energy costs, not only a decrease in demand, but also as a decrease in consumption. However, for the development of this methodology, it was necessary for evaluation, an assessment by companies that provide services in the area of energy conservation. These companies were selected from an investigation of customer satisfaction on services provided and results obtained after replacing the motors. By analyzing 266 cases, the problems found by these companies had been verified before, during and after the substitution of standard electric motors by high-efficiency ones. In some cases, the substitution of an old standard motor by a new high-efficiency one resulted in an increase of consumption of electric energy, and this fact is totally controversial when one expects savings of 2 to 6 % from this change of technologies, according to Eletrobrás and NEMA MG 1. The methodology MHmit developed in this work covers this situation. The main methodologies currently used to carry out studies to replace standard electric motors by high-efficiency ones were analyzed and presented in this work. Amongst them, the conventional methodology, which uses electric motor curves to determine efficiency, and the methodology that uses the program named BD Motor, developed by the Center of Research in Electric Energy of Eletrobrás, the methodology that uses the program Mark IV, developed by researchers from Federal University of Itajubá, in partnership with Procel/Eletrobrás and the IX program named Motor Master, developed by the North American Department of Energy (DoE). All these programs are freely available for download at Procel Info/Eletrobrás website - www.procelinfo.com.br. The MHmit methodology, developed in this work, presented satisfactory percentage values of deviations (10,12%), between the predicted values (during simulations with MHmit application) and real (by checking the real electric energy savings provided after the old standard motor replacement) when compared to the methodologies in study. These, do not include the old motor data parameters, making it difficult to obtain a true value of motor operation efficiency, because it may have gone through repairs, rewinding and short-circuits. The 86 case studies which were carried out for the validation of this methodology (motors with rated power from 7.5 to 125 hp) showed significant differences between the values provided by current methodologies and the methodology developed MHmit.
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Recovering Titanium Dioxide (TiO2) after its Use to Treat Leachate for Reuse on Future Leachate FlowsUnknown Date (has links)
This thesis was about finding a recovery method for TiO2, using a TiO2 recovery technology, which was high enough to be economical ($10 - $15 per 1,000 gallons) to be adopted by wastewater treatment plants. When comparing recovery technologies, the top three which were investigated further through experimentation were a centrifuge, sedimentation tank, and microfilter membrane. Upon experimentation and research, the TiO2 recovery efficiencies of these technologies were 99.5%, 92.5%, and 96.3%, respectively. When doing economic analysis on these technologies comparing TiO2 efficiencies and capital and operational costs, the centrifuge was the most preferred economic option. Also, its cost did were in the economical range ($10 - $15/1,000 gallons) which makes even this technology economical. Besides that, important and valuable information about TiO2: settling behavior, particle size and zeta potential, interactions with COD, and filter operations (particle characterization) were discovered for future research and future testing on this issue. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection
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