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ABSTRACT CHARACTERIZATION OF SERPENTINE FILLED POLYPROPYLENE Can, Semra Ph.D., Department of Polymer Science and Technology Supervisor: Prof. Dr. Teoman Tin&ccedil / er March 2008, 158 pages In this study, the aim is to prepare polypropylene (PP)/serpentine composites and study their mechanical, thermal and morphological properties. Another objective is to explore whether it is possible to have PP/serpentine nanocomposites with melt intercalation method by using the advantage of the layer silicate structure of serpentine. The most widely used fillers in PP are talc and mica which belong to the phyllosilicates group of silicate minerals. So far, there has been almost no study employing serpentine as filler in either any polymers or PP, although it also belongs to the same group of minerals as talc and mica. Accordingly, it was planned to divide the work into the study of two groups. In group 1, for the compositions with 2, 5, 10 and 20 wt% serpentine, the particulate filler effects of serpentine both alone and in the presence of surface treatments with hydrochloric acid (HCl) and silane coupling agent (SCA) were investigated. The most impressive results in terms of static and dynamic mechanical properties were achieved with SCA rather than HCl. When the effect of serpentine without any treatment is considered, reinforcing effect of it can easily be observed without deteriorating the composite properties even at high filler loadings. In group 2, the nanofiller effects of serpentine in 2 and 5 wt% filled compositions by modification of both the filler and the matrix were aimed to be examined with melt intercalation method. In addition to HCl and SCA treatments, maleic anhydride grafted polypropylene (PP-g-MA) and quaternary ammonium salt (QAS) of cetyl-trimethyl-ammonium bromide were used as compatibilizer and intercalating agent, respectively. While the amount of QAS was kept constant, different percentages of compatibilizer were employed. The presence of QAS and PP-g-MA further improved the properties with respect to group 1 members. Interestingly, the percentage strain at break values did not decrease as much as group 1 compositions with the same filler content. It can be concluded that partial intercalation of group 2 compositions was achieved, according to the X-ray and TEM results. Keywords: Serpentine, PP/serpentine composites, SCA, PP-g-MA, serpentine nanocomposites

Urban expansion of the City of Vancouver has resulted in increased land development of the municipality of Surrey, and more intensive agriculture on the remaining farmland. From 1980 to 1984 five different fish kills in the Serpentine River attributed to low dissolved oxygen were thought to be caused by a combination of agricultural discharges, high autumn water temperatures, as well as rainfall and river flow patterns. In 1985 an experimental instream aeration system was installed in a lower reach of the river in an attempt to provide additional oxygen during the critical autumn period. This study was undertaken to determine the extent of the agricultural drainage discharge problem. Weekly sampling from July to December, 1987, revealed that organic pollutional loading from dairy farms was high. Nutrients loadings in the river supported a heavy algal growth which resulted in an oxygen deficit during autumn algal die-off and decay. Although the flushing of farm ditches normally exerts an additional oxygen demand on the river, this was not observed in 1987 because the major autumn rains began on Oct 30, and lower water temperatures prevented a rapid exertion of the biodegradable oxygen demand. Implementation of source control of farm animal wastes is strongly recommended, along with a program of public education on conservation and management of natural habitat. Harvesting of filamentous algae in the river may eventually prove necessary for successful rehabilitation as diffused river aeration appears to be having a very small effect. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Student Number : 7729948 - MSc dissertation - School of Animal, Plant and Environmental Sciences - Faculty of Science / As early as 1583 an ultramafic plant was described (Proctor & Woodell, 1975). Since the early 1900s a number of works documenting ultramafic vegetation in various parts of the world have been published (Proctor & Woodell, 1975). The vegetation of the Great Dyke, Zimbabwe was only described in 1965 (Wild, 1965). Much has been written since then, however. It was only as recently as 1989 that any work on ultramafic vegetation in South Africa was published (Morrey et al., 1989), possibly because ultramafic vegetation in the Barberton Greenstone Belt is not noticeably different from that of the surroundings and outcrops are much smaller than the Great Dyke. Studies since then have documented the flora of the ultramafic soils of the Barberton Greenstone Belt (BGB) (Morrey et al., 1992; Williamson, 1994; Balkwill et al., 1997; Williamson et al., 1997; Changwe & Balkwill, 2003; Williamson & Balkwill in prep.). There are around 40 larger outcrops of ultramafic soil in the BGB, the largest of which are shown in Figure 1.1, and to date 29 endemic taxa have been discovered, 5 of which hyperaccumulate Ni (Williamson & Balkwill, in prep). Using IUCN criteria 21 of these taxa have recommended conservation status in the vulnerable categories and four are data deficient. With a number of threatened taxa and scientifically interesting and potentially useful Ni hyperaccumulators on the South African part of the BGB, it was likely that there were additional endemic taxa in Swaziland or additional populations of species collected in South Africa. The ultramafic sites in Swaziland (Figure 1.2) range in altitude from 4750 m above sea level (Figure 1.3) in the south to below 2250 m in the Komati River valley (Figure 1.4), higher than the South African sites which range from 354 – 1648 m above mean sea level (Balkwill et al., 1997). The Swaziland sites thus provide an opportunity to discover the effect of altitude on the vegetation of ultramafic soils in the BGB. The higher sites are cooler than the lowveld sites, with frost at night in winter and even snow on rare occasions. Rainfall averages 127 to 152 mm per year, the highest rainfall being recorded at the higher altitudes, where frequent fog also supplements the rainfall (Compton, 1966). The Swaziland sites also show a range of topography with the lower altitude sites often situated on the slopes of mountains, but higher altitude sites comparatively level. Very little of the ultramafic area in Swaziland has any form of protection and half the area has already been lost to agriculture and forestry. A previous study (Witkowski et al., 2001) identified Kniphofia umbrina Codd. as a critically endangered ultramafic endemic. There was thus an urgent need to study the remaining ultramafic areas and document the vegetation before more of this unique and important habitat is lost, and possibly some endemic plant species too. High population growth, expanding forestry and black wattle encroachment could all impact negatively on the remaining diversity of the ultramafic areas.

The overarching objective of this research project was to gain improved basic understanding of the fluid mechanisms governing the development of secondary flow structures in complex, three-dimensional inlet ducts. To accomplish this objective, particle image velocimetry measurements were employed to document the mean and turbulent flow properties within the complex flow regions. Complimentary, surface oil flow visualizations and static pressures were obtained to aid in the interpretation of the PIV data. Using these diagnostic techniques, the formation of a pair of counter-rotating vortices was revealed. Two-dimensional PIV measurements were conducted along 20 planes near the two bends of the duct model. All data was collected with an incoming freestream of 40 m/s. Over 2000 image pairs were collected for each measurement location, which were then processed and averaged to generate mean velocity, variance intensity, and velocity gradient statistics. The data was analyzed and it was determined that the experimental PIV data corresponded well with the qualitative flow visualization. This research will contribute to the particle image velocimetry database and subsequent analyses, which will provide additional insight into the flow structure and provide a new database for numerical model validation.

The overarching objective of this research project was to gain improved basic understanding of the fluid mechanisms governing the development of secondary flow structures in complex, three-dimensional inlet ducts. To accomplish this objective, particle image velocimetry measurements were employed to document the mean and turbulent flow properties within the complex flow regions. Complimentary, surface oil flow visualizations and static pressures were obtained to aid in the interpretation of the PIV data. Using these diagnostic techniques, the formation of a pair of counter-rotating vortices was revealed. Two-dimensional PIV measurements were conducted along 20 planes near the two bends of the duct model. All data was collected with an incoming freestream of 40 m/s. Over 2000 image pairs were collected for each measurement location, which were then processed and averaged to generate mean velocity, variance intensity, and velocity gradient statistics. The data was analyzed and it was determined that the experimental PIV data corresponded well with the qualitative flow visualization. This research will contribute to the particle image velocimetry database and subsequent analyses, which will provide additional insight into the flow structure and provide a new database for numerical model validation.

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Gas turbines are used to convert thermal energy into mechanical energy. The thermal efficiency of the gas turbine is directly related to the turbine inlet temperature. The combustion and turbine technology has improved to such an extent that the operating temperature in the turbine inlet is higher than the melting temperature of the turbine material. Different techniques are used to cope with this problem. One of the most commonly used methods is internal cooling of the turbine blades. Conventionally air from the compressor is used for this purpose but due to higher heat capacity, steam can be used as coolant. This opens up the possibility to increase the gas temperature. In the case of a combined cycle power plant, its availability provides a good opportunity to be used as a coolant. The trailing edge of the gas turbine blades is an important region as it affects the aerodynamics of the flow. The aerodynamics demands a sharp and thin trailing edge to reduce profile losses. The conventional method is the release of a lot of cooling air though a slot along the airfoil trailing edge. However in the case of internal only cooling designs, the coolant is not allowed to leave the channel except from the root section to avoid mixing of the gas in the main flow path with the coolant and loss of cooling medium. The challenge is to design an inner cooling channel, with the cooling medium entering and leaving the blade at the root section, which reduces the metal temperatures to the required values without an increase of the profile losses and at acceptable cooling flow rate and pressure drop. This thesis presents Computational Fluid Dynamic (CFD) based numerical work concentrated firstly on the flow and heat transfer in two-pass rectangular channels with and without turbulator ribs. The aspect ratio of the inlet pass was reduced to accommodate more channels in the blade profile in chord-wise direction. Additionally, the divider-to-tip wall distance was varied for these channels. Their effect on heat transfer and pressure drop was studied for smooth as well as ribbed channels.  It was followed by a numerical heat transfer study in the trapezoidal channel. Different RANS based turbulence models were used to compare the numerical results with the experimental results. Further, new designs to enhance heat transfer in the channel’s side walls (named as trailing edge wall) were studied. These include the provision of ribs at the trailing edge wall only, inline arrangement of ribs at the bottom as well as at the trailing edge wall and a staggered arrangement of these ribs. The final study was a conjugate heat transfer problem with an aim to propose the best internal cooling channel design to reduce the metal temperature of the trailing edge surface for the given thermal and flow conditions. A number of different options were studied and changes were made to get the best possible channel design. The results show that for a two-pass rectangular channel (both smooth and ribbed), the reduction in inlet channel aspect ratio reduces the pressure drop. For a smooth channel the reduction in the width of the inlet pass does not affect the heat transfer enhancement at the inlet pass and outlet pass regions. In case of ribbed channels, heat transfer decreases at the tip and bend bottom with decrease in the width of the inlet pass. Among different turbulence models used to validate numerical results against experimental results for case of trapezoidal channel, the low-Re k-epsilon model is found to be the most appropriate. Using the turbulence model that yields results that are closest to the experimental data, the staggered arrangement of ribs at the trailing edge wall is found to have maximum thermal performance. The results from the conjugate heat transfer problem suggest using steam as coolant if it is available as it requires less mass flow rate to get similar wall temperature values as compared to air at similar thermal and flow conditions. It is also found that staggered arrangement of ribs is the best option compared to others to enhance heat transfer in trailing edge of the gas turbine blade with the pressure drop in the cooling duct in the acceptable range. / Gasturbiner används för att omvandla värmeenergi till mekanisk energi. Den termiska verkningsgraden för en gasturbin är direkt relaterad till turbinen inloppstemperatur. Förbrännings- och turbintekniken har förbättrats så mycket att gastemperaturen i turbininloppet är högre än smälttemperaturen för turbinmaterialet. Olika tekniker används för att hantera detta problem. En av de vanligaste metoderna är intern kylningen av turbinbladen. Konventionellt luft från kompressorn används för detta ändamål, men på grund av högre värmekapacitet kan ånga användas som kylmedel. Detta öppnar för möjligheten att höja gasens temperatur. Vid ett kombikraftverk, ger dess tillgänglighet ett bra tillfälle att användas som kylmedel.   Den bakre delen av turbinbladen är ett viktigt område eftersom geometrin påverkar strömningen. Aerodynamiken kräver en skarp och tunn bakkant för att minska profilförlusterna. Den konventionella metoden för kylning av denna är att släppa ut en stor mängd kylluft genom en spalt längs bakkanten. Men i fallet med enbart inre kylning får kylmediet inte lämna skovelprofilen i strömningskanalen utan endast genom rotsektionen för att undvika blandning av förbränningsluften i turbinens strömningskanal med kylmediet och förlust av kylmedium.   Utmaningen är att utforma en inre kylkanal, i vilken kylmediet kommer in och lämnar bladet i rotsnittet som är tillräckligt bra för att hålla metalltemperaturen på normala värden utan att öka profilförlusterna och med acceptabla kylluftflöden och tryckfall.   Denna avhandling består av ett Computational Fluid Dynamics (CFD) baserat numeriskt arbetet koncentrerat på strömning och värmeöverföring först i två-pass rektangulära kanaler med och utan turbulensalstrande ribbor. Geometrin för inloppspassagen reducerades för att ge utrymme för fler kylkanaler inom bladets profil i kordans riktning. Dessutom varierades mellanväggens avstånd till toppväggen. Effekten på värmeöverföring och tryckfall studerades för båda kanalerna. Därefter följde en numerisk studie av värmeöverföringen i liknande men trapetsformade kanaler. Olika RANS baserade turbulensmodeller användes för att jämföra numeriska och experimentella resultat. Vidare har nya konstruktioner för att förbättra värmeöverföringen i kanalens sidoväggar och bakkant studeras. Dessa inkluderar turbulensribbor på enbart bakkantsväggen samt ribbor på såväl sidoväggar som på bakkantsväggen i linje med och förskjutna mot varandra. Den slutliga studien var ett sammansatt värmeöverföringsproblem bakkantens yta för ett visst angivet tillstånd i form av värmebelastning, tryck, temperatur och flöden. Ett antal olika alternativ har studerats och modifierats för att bästa möjliga kanalutformningen.   Resultaten visar att för en två-pass rektangulär kanal (både släta och ribbade), minskar tryckfallet när inloppskanalens geometri reducerades. För en slät kanal påverkar inte den minskade bredden på inloppskanalen värmeöverförning i inlopps- och utloppskanalerna. Vid ribbade kanaler minskar värmeöverföring vid toppen och på toppväggen med minskad bredd på inloppskanalen. Av de olika turbulensmodeller som används för att validera numeriska resultat mot experimentella för fallet med trapetsformad kanal visade sig låg-Re k-epsilon modellen den mest lämpliga. Genom att använda den turbulensmodell som är närmast experimentella data visar det att geometrin med förskjutna ribbor på bakkantsväggen har maximal termiska prestanda. Resultaten från det sammansatta värmeöverföringsproblemet framhåller användning av ånga som kylmedium om den finns tillgänglig eftersom den kräver mindre massflöde för att få samma värden på väggtemperaturerna jämfört med luft vid samma termiska tillstånd. Det kunde också visas att förskjutna turbulensribbor är det bästa alternativet jämfört med andra för att öka värmeöverföringen i bakkanten av ett gasturbinblad med acceptabelt tryckfall i kylkanalen. / QC 20111108

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xx, 176 p.; also includes graphics (some col.). Includes bibliographical references (p. 169-176). Available online via OhioLINK's ETD Center

The Wilderness lakes system represents a segmented barrier lagoon and comprises three interconnected lakes; Rondevlei, Langvlei and Eilandvlei. The latter is further linked by the Serpentine channel to the Touw river and Wilderness lagoon. The role of these channels, as well as a sluice in the Serpentine, in structuring certain aspects of the ecology of the system was investigated. An analysis of the salt budget of the lakes suggests that the Serpentine dampens tidaI processes to such an extent that they play only a minor role in the overall budget. Furthermore, the channel between Eilandvlei and Langvlei prevents any tidal salt input to the upper lakes. Their estuarine environments are however maintained by salt inputs which occur when the mouth is closed. This unusual phenemenon means that the sluice may have a minimal effect on the salt budget of the system because it is only closed when the mouth of the lagoon is open. Environmental conditions in each of the lakes, the Touw river and Wilderness lagoon were compared in terms of their physico-chemical characteristics and submerged macrophyte communities. A principal components analysis suggests that the physico-chemical environment of each lake is similar. The Touw river however has a very different environment, whilst that of Wilderness lagoon has some similarities to both the lakes and the river. During the study macrophyte communities recovered from a major recession which occurred between 1979 and 1981 . Biomasses in excess of 1000g m⁻² were recorded in both Langvlei and Eilandvlei. In the latter however, macrophyte growth was less prolific than in the former, as some areas of the littoral supported no growth at all. Macrophyte encroachment in the channels is a major factor inhibiting water flow between the lakes. This encroachment is most severe in the Eilandvlei/Langvlei channel where macrophytes covered 80% of the channel's area.The dominant fish fauna throughout the system is composed of a marine/estuarine migratory component. In the lakes the Mugilidae and Sparidae are the most common families, whilst in the lagoon and Touw river predators such as Lichia amia and Argyrosomus hololepidotus also commonly occur. Eilandvlei serves as the initial nursery area for most migratory species. An estimated 52000 fish migrated up the Serpentine towards Eilandvlei during February 1984 . Most fish do not penetrate as far as Langvlei, and this can be related to macrophyte encroachment in the Eilandvlei/Langvlei channel. However, it is argued that should this channel be dredged and the macrophytes removed, the nursery potential of the system would not be greatly enhanced . This is because environmental heterogeneity, in association with an abundance of food in Eilandvlei, make this lake the most attractive nursery area to juvenile marine/estuarine fish.