LD2668 .T4 1954 P47 / Master of Science

Call number: LD2668 .T4 1985 S364 / Master of Science

Call number: LD2668 .T4 1985 S566 / Master of Science

Following the development of detector technology, remote sensing image detection is being implemented with charge-coupled devices (CCD), which have promising features. The French SPOT system is the first civilian satellite sensor employing a CCD in its detection unit. In order to obtain the system transfer function (TF), a linear system model is developed in the across- and along-track directions. The overall system TF, including pixel sampling effects, is then used in the Wiener filter function to derive an optimal restoration function. A restoration line spread function (RLSF) is obtained by the inverse Fourier transform of the Wiener filter and multiplied with a window function. Simulation and empirical tests are described comparing the RLSF to standard kernels used for image resampling for geometric correction. The RLSF results in superior edge enhancement as expected.

Thesis (MScIng)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Conventional pulse oximetry has limited accuracy in measuring blood oxygen saturation in low saturation and perfusion scenarios. This limits the application of pulse oximetry in patients su ering from peripheral vascular a ictions. A novel pulse oximetry system is presented in this study which proposes solutions to these low saturation and perfusion issues. The presented system was designed to overcome the low perfusion issues by inducing an arti cial pulse in the detected photoplethysmograph. A novel arterio-venous hypothesis was formulated to extract arterial and venous saturation data from this arti cial photoplethysmograph using arterial-to-venous compliance ratios. Sensor wavelengths were selected to provide high and low saturation accuracy, followed by an in vitro sensor calibration procedure. System performance was validated by means of in vivo human studies. In vivo results indicate good accuracy for high saturation, with limited accuracy in low saturation scenarios. The arterio-venous hypothesis was validated, indicating that venous saturation information can be extracted from the arti cial PPG. Although inconclusive, results indicate that the proposed system might be able to accurately monitor arterial and venous saturation in severe hypoperfusion scenarios with recommended hardware and calibration modi cations. It is recommended that further studies into the presented system's performance are conducted. / AFRIKAANSE OPSOMMING: Konvensionele 'pulse oximetry' sisteme het beperkte akkuraatheid tydens die meting van bloed suurstof saturasie in lae saturasie en perfusie gevalle. Dit beperk die bruikbaarheid van 'pulse oximetry' in pasiënte wat ly aan perifere vaskulêre siektes. 'n Nuwe 'pulse oximetry' sisteem, wat oplossings vir hierdie lae saturasie en perfusie beperkings voorstel, word in hierdie studie aangebied. Die voorgestelde sisteem is ontwerp om die lae perfusie beperkings te oorkom deur 'n kunsmatige polsslag in die 'photoplethysmograph' te induseer. 'n Nuwe arterio-veneuse hipotese is geformuleer om arteriële en veneuse saturasie inligting uit hierdie kunsmatige polsslag te onttrek deur middel van 'n arteriële-teenoor-veneuse styfheids verhouding. Die gol engtes wat gebruik is in die sensors, is spesi ek gekies om hoë en lae saturasie akkuraatheid te verskaf. 'n In vitro kalibrasie prosedure is gevolg om die sensors vir hoë en lae saturasie te kalibreer, waarna die werkverrigting van die sisteem getoets is deur middel van 'n in vivo validasie prosedure. Die in vivo resultate toon goeie akkuraatheid vir hoë saturasie, met beperkte akkuraatheid vir lae saturasie. Die arterio-veneuse hipotese is gevalideer, wat aandui dat veneuse saturasie wel uit die kunsmatige 'photoplethysmograph' onttrek kan word. Alhoewel die resultate wat in hierdie studie aangebied word nie omvattend of beslissend is nie, dui dit egter aan dat die voorgestelde sisteem dalk in staat kan wees om arteriële en veneuse saturasie in uiters lae perfusie gevalle te meet. Verbeteringe sal egter aan die sisteem aangebring moet word in terme van hardeware en kalibrasie, om 'n meer gestandardiseerde metings metode te verseker. Verdere navorsing oor die werkverrigting van die voorgestelde sisteem word ook voorgestel.

Very early in the history of atomic emission spectroscopy (AES) it was understood to be a powerful analytical tool. Until the 1930's the usefulness of atomic spectroscopy was not utilized very extensively even though its fundamental power was understood. The breakthrough that placed it in the standard chemistry laboratory was the discovery and implementation of the photoelectric effect. Since this discovery there has been a revolution in atomic spectroscopy which has brought it from the role of a humble servant used for primary elemental screening to an outstanding leader in applications of elemental analysis. Atomic emission spectroscopy of complex samples has long suffered from matrix effects which result in overlapping of spectral lines, fluctuating backgrounds and changing conditions in the source. Investigations employing an echelle polychromator with a two dimensional solid state array detector show great promise in minimizing the effects of these interferences on multielement analyses of complex samples. The Charge Injection Device (CID) detector used exhibits many characteristics which make it uniquely qualified for simultaneous, multielement detection in AES. With only slight modifications to the optics of a commercial spectrometer and the employment of a CID detector, detection limits for a number of elements are quite favorable. Dynamic ranges of over seven orders of magnitude are obtainable with this experimental system. The reduction of matrix effects by utilizing the huge wealth of information available from over 60,000 individual detector elements are demonstrated through results from several complex matrix standards. This CID-polychromator system was also employed for the element selective detection of gas chromatographic (GC) effluents. A microwave-induced plasma (MIP) based on the Surfatron design was built. A helium plasma from this device has shown to have resilience to organic samples and give good emission response to non-metallic atoms. A number of studies with this GC-AES-polychromator system are presented. This system is capable of monitoring atomic emissions from C, H, F, Cl, Br, I, O, N and S all simultaneously, and the selectivity of this system is unsurpassed. Elemental ratios for separated compounds are also presented as a precursor to empirical formula prediction.

Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: A digital portal X-ray imaging system was developed to replace the radiographic X-ray films currently used for patient position verification at the National Accelerator Centre (NAC) proton therapy facility. The main advantage of a digital system is the short time in which the image can be obtained. Other advantages include optimisation of the image display, effective archiving of the digital images, access from various locations through data networks, and lower operational costs. The digital system described in this thesis consists of a Gd202S:Tb scintillator screen for converting X-rays to visible light, a protected aluminum front silvered mirror to direct the light to a Charge Coupled Device (CCD) camera for capture and a personal computer for data acquisition, processing and display. Compared with other digital imaging systems, this is a simple, compact and affordable system. The properties of the various components were investigated. The Rarex G-130 (Gd202S:Tb) scintillation screen was chosen for its good spatial resolution, high emission efficiency and good matching between the spectral emission wavelength peak and the quantum efficiency of the CCD camera. The spatial resolution measured for the system with a field of view (FOV) of 290 x 190 mnr' is 1.3 lp/mm, which can be improved by increasing the CCD chip resolution or decreasing the field of view, since the CCD camera limits the spatial resolution. Intrinsic detector noise determines the lower limit of the dynamic range of the detector and is reduced by cooling the CCD camera. A dark current exposure is subtracted from the image to remove the bias signal and background signal level mainly caused by thermal noise. Photon noise, beam in-homogeneity and efficiency variations across the CCD chip are removed by a flat field correction. The digital images obtained with this system compare very well with the currently used radiographic film images and they are satisfactory for the purpose of patient position verification. Using the digital system it is possible to reduce the patient dose by 19 % and still obtain satisfactory image quality. / AFRIKAANSE OPSOMMING: 'n Digitale X-straalafbeeldingstelsel is ontwikkel om die radiografiese X-straalfilm wat tans gebruik word vir die kontrolering van die pasientposisionering voor die toediening van protonterapie by die Nasionale Versnellersentrum, te vervang. Die voordeel van die digitale sisteem is dat die beelde feitlik onmiddellik beskikbaar is. Verdere voordele sluit die optimisering van die vertoon van beeldkontras, effektiewe liassering, vinnige bereik deur datanetwerke en lae lopende kostes in. Die digitale sisteem beskryf in die tesis bestaan uit 'n gadolinium oksi-sulfied (Gd202S:Tb) sintillasieskerm wat X-strale omskakel na sigbare lig, 'n eerste-oppervlak aluminiumspieël wat die lig na 'n digitale kamera (CCD kamera) weerkaats en In persoonlike rekenaar vir dataverwerwing, verwerking en vertoon. Vergeleke met ander digitale stelsels is hierdie digitale beeldingstelsel eenvoudig, kompak en bekostigbaar. Die eienskappe van die verskillende komponente van die stelsel is ondersoek. Die Rarex G- 130 (Gd202S:Tb) sintillasieskerm IS gekies vanweë goeie resolusie, hoë emissiedoeltreffendheid en die hoë omsettingsdoeltreffendheid van die digitale kamera by die spektrale emissiegolflengte van dié sintillasieskerm. Die ruimtelike oplosvermoë van die stelsel is bepaal met In veldgrootte van 290 x 190 mnr' as 1.3 lynpare per millimeter. Die ruimtelike oplosvermoë kan verhoog word deur die kameraresolusie te verhoog of die veldgrootte te verklein, omdat die resolusie van die kamera tans die oplosvermoë van die stelsel beperk. Intrinsieke ruis van die detektor beperk die onderste grens van die dinamiese reikwydte van die detektor en kan verminder word deur die kamera te verkoel. 'n Donkerstroom-beeld word van die X-straalbeelde afgetrek om die voorspanningsein en die agtergrondsein, wat hoofsaaklik veroorsaak word deur termiese ruis, te verwyder. Ruis wat ontstaan as gevolg van fluktuasies in die aantal fotone, nie-homogeniteite in die bundel of variasie van die sensitiwiteit in die skerm word verwyder met behulp van 'n plat vlak beeld. Die digitale beelde verkry met die stelsel vergelyk goed met die beelde wat tans op film geneem word en die beeldkwalitiet is voldoende vir die kontrolering van die pasientopstelling. Dit is moontlik om die pasiëntdosis met 19 % te verminder en steeds voldoende beeldkwaliteit te verkry.

Thesis (MMed)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Case Report - A case is described of central oxygen pipeline failure that occurred at a large academic hospital and its subsequent implications for managing the situation. Literature review - The literature review undertaken focused on the current state of affairs with regards to anaesthetic staff's knowledge of and preparedness for the management implications of central oxygen pipeline failure. The events I describe below demonstrate a significant deficiency in the staff’s understanding of and training for the crisis, which should be remedied to improve patient safety. Specific measures are suggested in the literature to prevent such incidents and guidelines are available to manage central oxygen pipeline failure. These are reviewed in this study. Recommendations - This study attempts to bring together the most critical aspects that need to be addressed to safely manage similar future incidents. Prevention should include measures to implement clearly stated disaster management plans and increased awareness with regards to the medical gas pipeline system (MGPS), simulation training, efficient alarm systems, personally conducted routine evaluations of equipment and emergency backup systems by anaesthesiologists and effective communication between hospital staff. Careful planning and successful coordination during maintenance and modification of the medical gas pipeline system, using piston-type or air-driven, rather than oxygen-driven, ventilators and optimal design of the hospital bulk oxygen system can contribute to reduce risks. In the event of central oxygen pipeline failure a specific sequence of actions should be taken by the anaesthesiologist and a clear institutional operational policy is described. / AFRIKAANSE OPSOMMING: Gevalsbeskrywing - 'n Geval van sentrale suurstoftoevoerversaking, wat plaasgevind het by 'n groot opleidingshospitaal, word bespreek. Daar word ook gekyk na die praktiese gevolge met betrekking tot die hantering van die situasie. Literatuurstudie - 'n Literatuurstudie is aangepak met die doel om te fokus op die huidige toedrag van sake betreffende narkosepersoneel se kennis en paraatheid in die hantering van sentrale suurstoftoevoerversaking. 'n Wesenlike gebrek aan begrip en opleiding aangaande hierdie onderwerp is geïdentifiseer – areas wat, met die nodige aandag, verbeter kan word ten einde die welstand van pasiënte te verseker. Spesifieke voorkomende maatreëls en hanteringsriglyne word voorgestel deur die literatuur en word gevolglik hersien in hierdie studie. Aanbevelings - Hierdie studie poog om kernaspekte aan te raak ten einde soortgelyke toekomstige voorvalle veilig en optimaal te kan hanteer. Voorkomende maatreëls behels onder meer die daarstelling van duidelik verstaanbare noodplanne, verbeterde bewustheid aangaande die mediese gaspypsisteem, simulasie-opleiding, doeltreffende alarmstelsels, effektiewe kommunikasie tussen hospitaalpersoneel, sowel as narkotiseurs wat self roetine-evaluasies van hul narkosetoebehore en -noodtoerusting uitvoer. Noukeurige beplanning en neweskikking tydens herstelwerk of werk aan die mediese gaspypsisteem, die gebruik van suierventilators (of dan lugaangedrewe in plaas van suurstofaangedrewe ventilators) en die optimale uitleg van 'n hospitaal se suurstoftoevoer, kan bydra om die risiko's te beperk. In die geval van sentrale suurstoftoevoerversaking behoort die narkotiseur stapsgewyse aksie te neem. 'n Duidelike institusionele noodbeleid word ook omskryf.

Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: In the highly competitive international wine markets, effective procurement of raw material could prove the difference between success or failure for a wine company. Therefore the researcher embarked on this study to create a model that will assist procurement decision makers in the South African wine industry in the strategic procurement of raw material. In order to create a model for procurement of raw material in the South African wine industry, qualitative research was conducted that included a study of literature, available material, views from experts as well as a content analysis from sample interviews. Procurement officials need to ensure that marketing forecasts are aligned with contracted procurement volumes. Cost, quality and availability should be tightly managed to minimise losses due to unallocated inventory or lack of raw material with sufficient quality or quantity to serve a marketing need. Suppliers should be prioritised in terms of strategic importance and procurement decision-makers should be crystal clear on which strategy to pursue with each quality segment and supplier in order to obtain the right quantity at the desired quantity and most economical price. Procurement decision makers need to evaluate the procurement and market environment for opportunities and threats that might impact on their ability to procure raw material from their supply base, and put measures in place to take control of possible effects of those uncertainties. This includes differentiating between grape procurement and wine procurement to leverage the advantages from both. Procurement officials must establish an action plan to limit the risk of cost, availability and quality by engaging and investing in trusting, loyal relationships with proficient suppliers with capacity. The procurement function should operate in a professional manner, building a track record of pro-active procurement and focus on loyal supplier relationships. / AFRIKAANSE OPSOMMING: In die hoogs kompeterende internasionale wynmarkte kan effektiewe aankope van rou-materiaal die verskil beteken tussen sukses of mislukking vir 'n wynmaatskappy. Daarom het die navorser begin met hierdie studie om 'n model te skep wat besluitnemers van aankope kan bystaan met die strategiese aankoop van roumateriaal in die Suid-Afrikaanse wynbedryf. Om 'n model te skep vir die aankoop van roumateriaal in die Suid-Afrikaanse wynbedryf is kwalitatiewe navorsing gedoen, wat 'n literatuurstudie insluit, sowel as 'n studie van beskikbare materiaal, sienings van kenners en 'n inhoudsanalise van steekproefonderhoude. Aankoopsbeamptes moet verseker dat bemarkingsvooruitskattings en gekontrakteerde aankoopvolumes ooreenstem. Koste, kwaliteit en beskikbaarheid moet streng bestuur word om verliese te beperk wat kan ontstaan deur ongeallokeerde voorraad of 'n tekort aan roumateriaal met genoegsame kwaliteit of hoeveelheid om 'n bemarkingsbehoefte te bevredig. Verskaffers moet prioritiseer word in terme van strategiese belangrikheid en aankoop-besluitnemers moet kristalhelder dink oor watter strategie om te volg met elke kwaliteitssegment en verskaffer, sodat die regte hoeveelheid en volume teen die mees ekonomiese prys aangekoop word. Aankoopbesluitnemers moet die aankoop- en markomgewing evalueer vir geleenthede en bedreigings wat 'n invloed kan hê op hul vermoë om roumateriaal van hul verskaffingskorps aan te koop, en moet maatreëls in plek stel om beheer te neem oor die moontlike effek van daardie onsekerhede. Maatreëls sluit in die differensiasie tussen druifaankope en wynaankope om die voordele van elk maksimaal te benut. Aankoopsbeamptes moet 'n aksieplan vestig om die risiko van koste, beskikbaarheid en kwaliteit te beperk deur in verbintenisse te belê met lojale vertrouensverhoudings met vaardige verkaffers met kapasiteit. Die aankoopsfunksie moet op 'n professionele manier optree, om 'n beeld van pro-aktiewe aankope te bou en 'n fokus op lojale verskafferverhoudings te vestig.

Thesis (MBA)--Stellenbosch University, 2007. / ENGLISH ABSTRACT: Desalination has been hailed by some as the answer to global freshwater supply shortages, but there is rigorous debate over the appropriateness of utilising desalination technology in regions that are not faced with severe water shortages. The aim of this research report is to provide a strategic overview of the South African desalination equipment market, a region where little research on this topic has been conducted. Secondary and thorough primary research in the form of interviews with desalination equipment suppliers and end users of desalination equipment in South Africa were conducted. The research findings revealed that the South African desalination equipment market, with a total annual revenue figure of R169.80 million in 2006 is very small when compared with the annual revenue figures of other global markets such as Saudi Arabia, which reached R6.61 billion in 2006. The industrial sector is the most active end user in South Africa followed by the commercial and lastly the municipal sector. It is anticipated however that the municipal sector, driven by coastal municipalities, will experience high growth in the medium to long term. Competition levels within the market were found to be high between desalination equipment suppliers, an attribute common in growth markets. Distinct market drivers, restraints and market trends were identified by research participants each of which have a varying influence on the desalination equipment market. South Africa has a fairly active desalination equipment market, which is small by global standards, and it is unlikely that desalination will solve South Africa’s water supply issues. Impoverished citizens, the high cost of desalination and the low cost of current fresh water sources all add to the complexity of the desalination debate in South Africa. / AFRIKAANSE OPOMMING: Ontsouting word deur sommige partye gesien as die antwoord op die wêreldwye vars water voorsieningstekorte, maar daar is breedvoerige debat oor die geskiktheid van ontsouting tegnologie in streke waar daar nie ernstige waterterkort is nie. Die doel van hierdie navorsingsverslag is om ’n strategies oorsig te lewer van die Suid Afrikaanse ontsoutingsmark, ’n streek waarin daar tot dusver min navorsing oor hierdie veld gedoen is. Sekondêre en primêre navorsing in die vorm van onderhoude met ontsoutings-toerusting en eindgebruikers van hierdie toerusting in Suid Afrika is gedoen. Die bevindinge toon dat die Suid Afrikaanse ontsoutings-toerusting mark, met ’n omset van R169.8 miljoen in 2006, baie klein is wanneer dit vergelyk word met ’n mark soos Saudi Arabië, met ’n omset van R6.6 miljard in 2006. Die industriële sektor is die mees aktiewe eidgebruiker in Suid Afrika, gevolg deur die kommersiële en laastens die munisipale sektor. Dit word egter geantisipeer dat die munisipale sektor, gedryf deur kus-munisipaliteite, die grootste groei in die medium tot lang termyn gaan toon. Dei bevindeninge wys verder op hoë vlakke van kompetisie tussen ontsoutings-toerusting voorsieners, ’n algemene verskynsel in groei-markte. Verskeie mark-drywers, beperkings en tendense is deur deelnemers in die navorsing geïdentifiseer, met elk wat ’n wisselende invlied op die ontsoutings-toerusting mark het. Suid Afrika het ’n redelike klein aktiewe ontsoutings-toerusting mark in wêreld-terme en dit is onwaarskynlik dat ontsouting Suid Afrika se water-probleme sal oplos. Arm inwoners, die hoë koste van ontsouting en die huidige lae koste van vars water dra alles by tot die kompleksiteit van die ontsoutingsdebat in Suid Afrika.