The objective of this thesis was to improve a paraffin actuated micropump design, to be able to pump against extreme pressures (above 100 bar). This was accomplished by initially studying the membrane activation, using video capturing. The micropump has been improved to withstand pressures high enough, to enable use in an high-performance liquid chromatography (HPLC) system. The micropump has been shown to pump against back pressures up to 150 bar, with a positive net-flow. This should be compared with the previously recorded maximum back pressure of 50 bar. The pumping against high back pressures was possible due to an increased understanding of the sealing of the membranes. This resulted in a new design that was manufactured and characterised. Without clamping the pump was measured to manage back pressures of 10 bar, and then starting to leak in a bond at the flow channel. With supporting clamping, the managed back pressures increased ten folded. When measured on the different valves, pressure above 200 bar has been possible to withhold. Although the valves were below their maximum limit, the pressure was not possible to be further increased due to a limitation in the equipment, i.e. risk of damaging the connections. When examined after pressurised at extreme pressures (above 100 bar) several times, no signs of fatigue or damage of the membrane was seen. A new behaviour of the valves was discovered. Above certain pressures some designs self sealed, i.e. withholding the pressure after the voltage was turned off. For these valves the pressure had to be released by some other means.

The majority of low income households in South Africa have limited access to electricity, and typically cook on stoves fuelled by paraffin. Paraffin represents a fossil fuel. It is a relatively cheap fuel in South Africa. Another fuel that can also be used for cooking is wood pellets, which is a renewable fuel. It can be used in a similar way to that of paraffin and is relatively cheap compared to other renewable energy sources. To investigate if living conditions among low income households can be improved the focus of the study was to evaluate the sustainability of cooking on paraffin and wood pellets. This was done by comparing social, environmental and economic aspects associated with the two cooking fuels. The social aspects were investigated through an interview study, the environmental aspect through a comparative life cycle assessment (LCA) and the economic aspects through a partial life cycle cost analysis (LCCA) focusing on the user phase.   The interview study showed that paraffin users considered four aspects as the most important when cooking, namely safety, health, affordability and quality. The study also found that the majority were willing to change to another cooking fuel if these aspects were fulfilled. The LCA showed that both systems score the highest on 9 out of 18 environmental impact categories over a 16-year perspective. The economic analysis showed that the user phase of the wood pellet system is more economically beneficial during the 16-year time period than the paraffin system. It was concluded that wood pellets could be used as an option to paraffin for cooking and would most likely increase living conditions for low income households. / Majoriteten av låginkomsthushåll i Sydafrika har begränsad tillgång till elektricitet och vanligtvis sker matlagningen på paraffinspisar. Paraffin är ett fossilt bränsle. Det är ett relativt billigt bränsle i Sydafrika. Ett annat bränsle som också kan användas för matlagning är träpellets som är ett förnyelsebart bränsle. Det kan användas på liknande sätt som för paraffin och är ganska billigt i jämförelse med andra förnybara energikällor. För att undersöka om levnadsförhållanden för låginkomsthushåll kan förbättras låg fokus för denna studie på att utvärdera hållbarheten för att laga mat på paraffin och träpellets. Detta genomfördes genom att jämföra sociala, miljömässiga och ekonomiska aspekter associerade med dessa bränslen för matlagning. De sociala aspekterna undersöktes genom en intervjustudie, de miljömässiga aspekterna genom en jämförande livscykelanalys (LCA) och de ekonomiska aspekterna gjordes genom en livscykelkostnadsanalys (LCCA) för användarfasen.   Intervjustudien visade att paraffinanvändare anser att fyra aspekter är de viktigaste vid matlagning, nämligen säkerhet, hälsa, kostnad och kvalitet. Studien visade också att majoriteten var villiga att byta till ett annat bränsle för matlagning om dessa aspekter var uppfyllda. Livscykelanalysen visade att båda systemen hade högst miljöpåverkan i 9 av 18 miljöpåverkanskategorier vardera inom ett 16-årsperspektiv. Den ekonomiska analysen visade att under en 16-årsperiod var användarfasen mer kostnadseffektiv för matlagning på träpellets jämfört med paraffin. Studien visade att träpellets kan användas som ett alternativ för paraffin vid matlagning och kommer troligtvis öka levnadsförhållanden för låginkomsthushåll.

The majority of low income households in South Africa have limited access to electricity, and typically cook on stoves fuelled by paraffin. Paraffin represents a fossil fuel. It is a relatively cheap fuel in South Africa. Another fuel that can also be used for cooking is wood pellets, which is a renewable fuel. It can be used in a similar way to that of paraffin and is relatively cheap compared to other renewable energy sources. To investigate if living conditions among low income households can be improved the focus of the study was to evaluate the sustainability of cooking on paraffin and wood pellets. This was done by comparing social, environmental and economic aspects associated with the two cooking fuels. The social aspects were investigated through an interview study, the environmental aspect through a comparative life cycle assessment (LCA) and the economic aspects through a partial life cycle cost analysis (LCCA) focusing on the user phase. The interview study showed that paraffin users considered four aspects as the most important when cooking, namely safety, health, affordability and quality. The study also found that the majority were willing to change to another cooking fuel if these aspects were fulfilled. The LCA showed that both systems score the highest on 9 out of 18 environmental impact categories over a 16-year perspective. The economic analysis showed that the user phase of the wood pellet system is more economically beneficial during the 16-year time period than the paraffin system. It was concluded that wood pellets could be used as an option to paraffin for cooking and would most likely increase living conditions for low income households. / Majoriteten av låginkomsthushåll i Sydafrika har begränsad tillgång till elektricitet och vanligtvis sker matlagningen på paraffinspisar. Paraffin är ett fossilt bränsle. Det är ett relativt billigt bränsle i Sydafrika. Ett annat bränsle som också kan användas för matlagning är träpellets som är ett förnyelsebart bränsle. Det kan användas på liknande sätt som för paraffin och är ganska billigt i jämförelse med andra förnybara energikällor. För att undersöka om levnadsförhållanden för låginkomsthushåll kan förbättras låg fokus för denna studie på att utvärdera hållbarheten för att laga mat på paraffin och träpellets. Detta genomfördes genom att jämföra sociala, ekologiska och ekonomiska aspekter associerade med dessa bränslen för matlagning. De sociala aspekterna undersöktes genom en intervjustudie, de miljömässiga aspekterna genom en jämförande livscykelanalys (LCA) och de ekonomiska aspekterna gjordes genom en livscykelkostnadsanalys (LCCA) för användarfasen. Intervjustudien visade att paraffinanvändare anser att fyra aspekter är de viktigaste vid matlagning, nämligen säkerhet, hälsa, kostnad och kvalitet. Studien visade också att majoriteten var villiga att byta till ett annat bränsle för matlagning om dessa aspekter var uppfyllda. Livscykelanalysen visade att båda systemen hade högst miljöpåverkan i 9 av 18 miljöpåverkanskategorier vardera inom ett 16-årsperspektiv. Den ekonomiska analysen visade att under en 16-årsperiod var användarfasen mer kostnadseffektiv för matlagning på träpellets jämfört med paraffin. Studien visade att träpellets kan användas som ett alternativ för paraffin vid matlagning och kommer troligtvis öka levnadsförhållanden för låginkomsthushåll.

Thesis (PhD)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: In this study the deoiling and fractionation of paraffin wax using supercritical fluid extraction (SCFE) has been investigated. SCFE was compared with state-of-the-art processes such as wax crystallisation, static crystallisation and short path distillation. Ethane and carbon dioxide were investigated as supercritical solvents for the supercritical fluid extraction of paraffin wax. Supercritical phase equilibrium data for ethane - n-alkane and CO2 - n-alkane systems close to the mixture critical region were obtained from the literature, and were correlated with several equations of state. Statistical mechanical equations of state failed to correlate the data close to the mixture critical region due to the neglect of density fluctuations which influences phase behaviour close to critical points, or due to inadequate mixing rules. It was found that simple cubic equations of state such as Soave-Redlich-Kwong, Peng-Robinson and Patel-Teja could correlate the data using two interaction parameters. This can be attributed more to their flexibility as correlating tools than to their fundamental accuracy. The Patel-Teja EOS was modified by fitting it to predict low vapour pressure data for long-chain n-alkanes. This modified Patel-Teja EOS was then fitted to the phase equilibria by adjusting two interaction parameters per binary system. The interaction parameters for each solvent (ethane or CO2) system were then fitted to generalised correlations to enable extrapolation to solvent - n-alkane systems for which no equilibrium data were available. The Simplified Perturbed Hardchain theory (SPHC) equation of state was used to correlate lower-pressure solubility data used to model the extract separator. A pilot plant SCFE unit was constructed and used to obtain experimental fractionation data of a low-molecular weight Fischer-Tropsch wax. The experimental results indicate that fractionation of the wax is possible and that the separation efficiency is enhanced by returning some of the extract to the column as reflux. An equilibrium stage model was constructed and used to simulate the extraction experiments. It was possible to obtain good agreement between the experimental results and model predictions. Deoiling of petroleum waxes with a low n-paraffin content (which are not currently deoiled commercially) was investigated. Experimental SCFE and SPD results indicated that selective deoiling is not possible, since the separation is based on differences in molecular weight (or vapour pressure). Simulations of wax crystallisation or solvent extraction and practical tests indicate that deoiling is possible, based on differences in structure and therefore melting point of the components in the wax. Practical problems associated with crystallisation or solvent extraction such as filtration, the use of chlorinated solvents and low yields currently prevent the commercial deoiling of these waxes. During crystallisation of these waxes a soft wax cake is formed which impedes the operation of static crystallisation. A detailed study of the economics of n-paraffin wax deoiling using SCFE was conducted. Flow sheets were proposed to minimise the energy consumption of the SCFE process. Comparison of SPD, static crystallisation and SCFE indicates that a SPD plant will be the cheapest option for deoiling the wax feed investigated. Fractionation of heavier waxes using SPD might not be economically feasible, since the distillation temperature increases dramatically with increasing molecular weight, which leads to higher energy cost. For medium to long chain n-paraffin waxes SCFE should be very competitive, since the capacity of the supercritical solvent can be manipulated to extract longer chain waxes without increasing the extraction temperature. Static crystallisation appears to be the more expensive deoiling option, due primarily to the large initial capital investment cost. / AFRIKAANSE OPSOMMING: Die olieverwydering en fraksionering van paraffienwasse met behulp van superkritiese ekstraksie is in hierdie studie ondersoek. Die modellering van moderne olieverwyderings- en fraksioneringsmetodes soos waskristallisasie, statiese kristallisasie en kortpad distillasie is ook ondersoek. Etaan en koolstofdioksied is ondersoek as superkritiese oplosmiddels vir die superkritiese ekstraksie van paraffienwasse. Literatuurdata van superkritiese fase-ewewigte vir etaan - n-alkaan en CO2 - n-alkaan stelsels naby die mengselkritiese punt is versamel en gekorreleer met verskeie toestandsvergelykings. Statisities-meganiese toestandsvergelykings kon nie data naby mengselkritiese punte korreleer nie, moontlik weens digtheidsvariasies wat afwykings van klassieke gedrag teweegbring, of onakkurate mengreëls. Eenvoudige kubiese toestandsvergelykings soos Soave-Redlich-Kwong, Peng-Robinson en Patel-Teja kon op die ewewigsdata gepas word deur gebruik van twee interaksieparameters. Dit kan eerder toegeskryf word aan hulle buigsaamheid eerder as hulle fundamentele akkuraatheid. Die Patel-Teja toestandsvergelyking is gemodifiseer deur dit te pas op lae dampdruk data van langketting n-alkane. Hierdie gemodifiseerde toestandsvergelyking is gepas op die fase-ewewig data deur twee interaksieparameters te gebruik per binêre sisteem. Die interaksieparameters vir die oplosmiddel stelsels (etaan of CO2) is gekorreleer met algemene vergelykings sodat dit vir ekstrapolasie na oplosmiddel - n-alkaan stelsels gebruik kan word waarvoor ewewigsdata nie beskikbaar is nie. Die "Simplified Perturbed Hardchain" teorie (SPHC) toestandsvergelyking is gebruik om laer druk oplosbaarheidsdata te korreleer vir gebruik in die modellering van die ekstrak skeier. In Superkritiese ekstraksie loodsaanleg is gebou en gebruik om eksperimentele fraksioneringsdata van 'n lae molekulêre massa Fischer- Tropsch was te genereer. Vanaf die eksperimentele resultate blyk fraksionering van was moontlik te wees. Die doeltreffendheid van die skeiding kan verhoog word deur terugvloei van ekstrak na die kolom. 'n Ewewigsmodel is opgestel en gebruik om die ekstraksie eksperimente te modelleer. Deur die ekstraksiedruk en aantal stadia te verander kon goeie ooreenstemming met eksperimentele resultate verkry word. Die verwydering van olie uit petroleumwasse met In lae n-paraffien inhoud (wat nie tans kommersiëel ontolie word nie) is ondersoek. Eksperimentele resultate vir superkritiese ekstraksie en kortpad distillasie dui daarop dat selektiewe olieverwydering nie moontlik is nie, omdat die skeiding gebaseer is op verskille in molekulêre massas en dus (of dampdrukke). Simulasies van waskristallisasie dui op die moontlikheid van olieverwydering gebaseer op verskille in strukture van die komponente in die was. Praktiese probleme geassosieer met kristallisasie of oplosmiddel ekstraksie soos filtrasie, lae opbrengste en gebruik van gechlorineerde koolwaterstowwe as oplosmiddel belemmer die kommersialisering van olieverwydering vir hierdie tipes wasse. 'n Gedetaileerde studie van die ekonomiese lewensvatbaarheid van superkritiese olieverwydering is uitgevoer. Vloeidiagramme is voorgestelom die energieverbruik van die superkritiese ekstraksieproses te minimeer. Vergelyking van kortpad distillasie, statiese kristallisasie en superkritiese ekstraksie dui daarop dat kortpad distillasie die goedkoper opsie vir die olieverwydering van die spesifieke was is. Fraksionering van swaarder wasse met kortpad distillasie sal moontlik nie haalbaar wees nie omdat die distillasietemperatuur drasties toeneem met molekulêre massa. Die skeiding van medium tot langketting wasse met superkritiese ekstraksie behoort meer mededingend te wees, want die kapasiteit van die superkritiese oplosmiddel kan maklik verstel word om langer kettinglengtes wasse te ekstraeer sonder om die temperatuur te verhoog. Statiese kristallisasie blyk die duurder olieverwyderingsopsie te wees hoofsaaklik weens die hoë kapitaalkoste van so 'n aanleg.

Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Paraffin, also called kerosene is used by small-scale soya bean farmers in some parts of Africa as a pest repellent. The repellent action is claimed to be effective against parasites during seed germination and development of the seedlings. Seeds are immersed in commercial paraffin for a few seconds and sown in the soil immediately. This method raised some questions about possible negative effects on the seed after the imbibition process but also on humans and animals consuming the plants and seeds. Experiments were designed to investigate whether this practice would have negative effects on seed germination and vigour of the resulting seedlings of seven selected crop species. A trial was also carried out to test the effectiveness of paraffin as a pest repellent on canola in a field situation. The collected data were analyzed using STATISTICA, software version 11. Wherever the experiments showed significant interaction or differences within main factors, the means were separated making use of Fischer’s LSD post-hoc analysis at p = 0.05. The first series of experiments was done in the laboratory. It was carried out on seeds of seven crop species: canola (Brassica napus L.), common beans (Phaseolus vulgaris L.), ground nuts (Arachis hypogea L.), maize (Zea mays L.), soya bean (Glycine max L.), sunflower (Helianthus annuus L.) and wheat (Triticum aestivum L.). In the germination trial, seeds were subjected to a 7X5X4 factorial design treatment with factors Crop species (CS) (see above), Paraffin concentration (PC) (0, 25, 50, 75 and 100% of commercial paraffin diluted with distilled water) and Time of immersion (TOI) (1, 5, 10, and 30 minutes). Treatments were repeated four times. After immersion seeds were dried with water absorbent paper and immediately germinated in 90 mm diameter petri dishes containing two filter papers and 5 ml of distilled water. Germination tests included 10 seeds per replicate and were incubated at a constant temperature of 20°C under dark conditions in an incubator. Findings showed that canola, sunflower and soya bean are paraffin tolerant (>70 % germination), wheat and groundnuts are less tolerant (30% – 70% germination) and beans and maize are intolerant (< 30 % germination). The paraffin had a negative influence on the rate of germination but there were no statistically significant differences between the 25% to 100% paraffin concentrations. Measurements of the quantity of water and of paraffin absorbed were done after seeds of the seven crop species were immersed in 0, 25, 50, 75 and 100% paraffin concentrations for 30 minutes. Beans absorbed more water at 100% water and more paraffin at 25% paraffin than the other crop species. The paraffin uptake decreased with the increase of paraffin concentration while water uptake increased with the increase in water percentage. In both cases canola had the lowest uptake. Differential uptake of water and paraffin did not explain the results of the germination test. Seeds of the seven crop species immersed in different paraffin concentrations (0, 25, 50, 75 and 100%) for thirty minutes were dried and then soaked in distilled water for 20 hours. The electrical conductivity (EC) of the liquid was determined by means of an EC meter after 20 hours of soaking. This was done to investigate whether paraffin treatment influenced leaking of electrolytes, which would indicate damage to the cell membranes in the seed. Results showed that sunflower leaked more electrolytes than any other seed, while wheat and maize had lower electrolyte leakage than the other species. This showed that the negative effect of paraffin on the germination of some crop species was unlikely to be due to membrane damage because sunflower seeds that leaked most electrolytes had a high germination percentage while the maize and wheat seeds that leaked little electrolytes, had poor germination after paraffin treatments. The second experiment was conducted in a glasshouse. Seeds of the seven crop species were subjected to the same PC and TOI treatments as described in the germination experiment above but instead of being placed in an incubator to germinate, they were planted in 8cm x 8 cm plastic pots (10 seeds in each) in coarse sand in a glasshouse that was running at approximately 20ºC. The establishment of the seedlings was monitored daily in the glasshouse. The final percentage of establishment was calculated. Three weeks after planting, the seedlings were thinned to one plant per pot. The mean root and stem lengths as well as dry mass of the seedlings was recorded when the seedlings were thinned. The one plant per pot that was retained was harvested six weeks after establishment. Root and stem length and dry mass were determined. Establishment percentage and tolerance indices were calculated. Maize and beans showed the lowest establishment percentages and sunflower scored the highest establishment percentage after treatment with paraffin. The root and stem lengths of the crops were generally unaffected by paraffin treatments. In terms of dry mass paraffin had a significant negative effect on groundnut at three weeks but at six weeks no effect of paraffin on any of the vegetative growth parameters could be observed. The third experiment was run in the microscope laboratory. A test using a confocal and fluorescence microscope was carried out to determine if residues of paraffin could be found in germinating soya bean seeds and seedlings. Specimens collected from the germinating soya bean seed and seedlings were mounted on the fluorescent microscope and stained with a solution of 100 μg.ml-1 Nile Red and observed with LD Plan-Neofluar 60X/0.6. Results showed that paraffin did penetrate the soya bean seed and was translocated within the plant system (endodermis) as the plant grows. The concentrations of paraffin in the tissue were however quite low. The fourth experiment was run on the Langgewens Experimental Farm near Moorreesburg in the Western Cape Province. Forty blocks were spatially grouped into two separate groups. Twenty blocks received the five paraffin treatments replicated four times and the other twenty blocks received the five water treatments also replicated four times. Within each group the treatments were allocated randomly to the plots. The experimental design was a 2X5 Factorial experiment with factors Treatment liquid (distilled water and paraffin) and Time of immersion (0, 1, 5, 10 and 30 minutes) replicated four times. No pesticides were applied to the canola crop. Stand density, leaf area and dry mass were recorded at the first harvest at 12 weeks, and then dry mass was determined at 21weeks. Final yield was determined after 27 weeks when the plots were harvested by means of a combine plot harvester. The stand density, leaf area and dry mass were significantly increased by paraffin treatments at the time of the first harvest. After 21 weeks paraffin treatment had no significant effect on the dry mass production of the canola and the same was true of the final seed yield. . Even though there was no serious attack by pests, the little feeding damage that occurred in the water treated plots and not in the paraffin treated plots, indicate that paraffin may have a repellent effect. Paraffin had no negative effects whatsoever on the growth and yield of canola in this experiment. This study indicates that different crops react differently to seed treatment with paraffin. The results of the fourth experiment indicate that paraffin might be used as pest repellent on certain selected crops but more research is needed on the subject. / AFRIKAANSE OPSOMMING: Paraffien, ook genoem keroseen, word deur kleinskaalse boere in sekere dele van Afrika gebruik as ‘n pesafweermiddel. Dit word beweer dat die afweeraksie suksesvol is teen parasiete tydens saadontkieming en vroeë saailinggroei. Saad word in kommersiële paraffien gedoop vir ‘n paar sekondes en dan onmiddelik daarna geplant. Die metode skep vrae oor die moontlike negatiewe gevolge op die saad na die imbiberingsproses maar ook op mense en diere wat die plante en sade benut. Eksperimente is beplan om vas te stel of die praktyk negatiewe gevolge op die saadontkieming en groeikragtigheid van die daaropvolgende saailinge van sewe geselekteerde gewasspesies sal hê. ‘n Eksperiment is ook uitgevoer om die effektiwiteit van paraffien as pesafweermiddel op kanola in ‘n veldsituasie te toets. Die data wat ingesamel is is ontleed deur gebruik te maak van STATISTICA, sagteware, uitgawe 11. Waar betekenisvolle interaksies of verskille binne hooffaktore voorgekom het, is die gemiddeldes geskei deur middel van Fischer se LSD post-hoc ontleding by p = 0.05. Die eerste reeks eksperimente is uitgevoer in ‘n laboratorium. Dit is uitgevoer op sade van sewe gewasspesies naamlik . kanola (Brassica napus L.), gewone bone (Phaseolus vulgaris L.), grondbone (Arachis hypogea L.), mielies (Zea mays L.), sojabone (Glycine max L.), sonneblom (Helianthus annuus L.) en koring (Triticum aestivum L.). In die ontkiemingsproef is die sade onderwerp aan ‘n 7X5X4 ewekansige blokontwerp wat faktoriaal gerangskik is met faktore Gewasspesies (CS) (sien hierbo), Paraffien konsentrasie (PC) (0, 25, 50, 75 en 100% van kommersiële paraffien verdun met gedistilleerde water) en Tyd van indompeling (TOI) (1, 5, 10, en 30 minute). Behandelings is vier keer herhaal. Na indompeling is die sade met waterabsorberende papier gedroog en onmiddelik daarna in 90 mm deursneë petribakkies wat twee filtreerpapiere en 5 ml gedistilleerde water bevat het, ontkiem. Tien sade per petribakkie is gebruik en die petribakkies is geïnkubeer by ‘n konstante temperatuur van 20ºC in die donker in ‘n inkubasiekas. Resultate het getoon dat kanola, sonneblom en sojaboon bestand is teen paraffienbehandelings (>70% ontkieming), koring en grondboon is minder bestand (30-70% ontkieming) en mielies en gewone bone is sensitief vir paraffienbehandeling (<30% ontkieming). Die paraffien het oor die algemeen ‘n negatiewe effek op ontkiemingstempo gehad maar daar was geen statisties betekenisvolle verskille tussen die 25% en 100% paraffienbehandelings nie. Die hoeveelheid water en paraffien wat opgeneem is deur sade van die sewe gewasspesies nadat dit in paraffienkonsentrasies van 0, 25, 50, 75 en 100% ingedompel is vir 30 minute, is bepaal. Gewone bone het meer water by die 100% water behandeling en meer paraffien by die 25% paraffien behandeling opgeneem as die ander spesies. Die paraffienopname het afgeneem met toename in paraffienkonsentrasie terwyl wateropname toegeneem het met toenemende waterkonsentrasies. Beide in geval van wateropname en paraffienopname het kanola die minste water opgeneem. Differensiële opname van water en paraffien het nie die resultate van die ontkiemingstoets verklaar nie. Sade van die sewe gewasspesies is in verskillende paraffienkonsentrasies (0, 25, 50, 75 en 100%) gedompel vir 30 minute, gedroog en daarna in gedistilleerde water geweek vir 20 uur. Aan die einde van die 20 uur wekingsperiode is die elektriese konduktiwiteit (EC) van die wekingsvloeistof bepaal deur middel van ‘n EC meter. Dit is gedoen om vas te stel of paraffienbehandeling die uitlek van elektroliete vanuit die saad, wat ‘n aanduiding van beskadigde selmembrane van die saad kan wees, beïnvloed. Resultate het aangedui dat sonneblom die meeste elektroliete vrygestel het en koring en mielies die minste. Dit dui aan dat die negatiewe invloed van paraffien op sommige gewasspesies waarskynlik nie deur membraanbeskadiging veroorsaak is nie omdat sonneblom, wat die meeste elektroliete vrygestel het, die hoogste ontkiemingspersentasie na behandeling met praffien gehad het terwyl mielies en koring, wat die minste elektroliete vrygestel het, baie swak ontkieming gehad het na paraffienbehandeling. Die tweede eksperiment is in ‘n glashuis uitgevoer. Sade van die sewe gewasspesies is onderwerp aan dieselfde paraffienkonsentrasies en tye van indompeling as in die ontkiemingseksperiment hierbo maar in plaas van om die sade in ‘n inkubasiekas te ontkiem, is dit in 8 cm x 8 cm plastiekpotte wat gevul is met growwe sand geplant (10 sade per pot) in ‘n glashuis wat by ‘n konstante temperatuur van ongeveer 20ºC geloop het. Die vestiging van die saailinge in die glashuis is daagliks gemonitor en die finale persentasie van vestiging is bereken. Drie weke na plant is die saailinge uitgedun sodat een per pot oorgebly het. Die uitgedunde saailinge se gemiddelde wortel- en stamlengtes is bepaal asook die gemiddelde droëmassas. Die een plant wat per pot oorgebly het is na ses weke ge-oes en weer is wortel- en stamlengtes bepaal asook die droëmassas. Vestigingspersentasies en toleransie indekse is bereken. Mielies en gewone bone het die laagste vestigingspersentasies getoon en sonneblom die hoogste nadat die gewasse met paraffien behandel is. Die wortel- en stamlengtes van die gewasse was oor die algemeen nie deur paraffienbehandelings beïnvloed nie. In terme van droëmassa het paraffien ‘n negatiewe effek op grondbone gehad drie weke na plant maar na ses weke kon geen invloed van paraffienbehandelings op enige van die vegetatiewe groeiparameters waargeneem word nie. Die derde eksperiment is in ‘n mikroskooplaboratorium uitgevoer. ‘n Konfokale en fluoreserende mikroskoop is gebruik om te bepaal of oorblyfsels van paraffien gevind kan word in ontkiemende sojaboonsade en saailinge. Monsters wat geneem is van die ontkiemende sojaboonsade saailinge is gemonteer op die fluoreserende mikroskoop en gekleur met ‘n oplossing van 100 μg.ml-1 Nile Red oplossing en ge-evalueer met LD Plan-Neofluar 60X/0.6. Resultate het getoon dat paraffien wel die sojaboonsaad kon infiltreer en dat dit ook in die saailinge se endodermis vervoer kon word en opspoorbaar was. Die konsentrasies van paraffien in die weefsel was egter laag. Die vierde eksperiment is uitgevoer op die Langgewens Proefplaas naby Moorreesburg in die Wes-Kaap Provinsie. Veertig blokke is ruimtelik in twee groepe van twintig elk grangskik. Twintig blokke het die vyf paraffienbehandelings ontvang en twintig die vyf gedistilleerde waterbehandelings. Die behandelings is vier keer herhaal. Binne elke blok is die behandelings ewekansig toegeken aan persele. Die proefontwerp was ‘n 2X5 ewekansige geneste blokontwerp (split plot) wat faktoriaal gerangskik is met faktore Behandelingsvloeistof (gedistilleerde water en paraffien) en indompelingstyd (0, 1, 5, 10 and 30 minute). Geen insekdoders is op die kanola toegedien nie. Plantdigtheid, blaaroppervlakte en droëmassa is bepaal tydens die eerste monsterneming 12 weke na plant en daarna is slegs droëmassa bepaal na 21 weke. Na 27 weke is finale oesopbrengs bepaal deur die persele met ‘n perseelstroper te stroop. Plantdigtheid, blaaroppervlakte en droëmassa is betekenisvol verhoog deur paraffienbehandelings na 12 weke. Na 21 weke het die paraffienbehandelings egter geen betekenisvolle invloed op die droëmassa van die plante gehad nie en daar was ook nie verskille ten opsigte van finale oesopbrengs nie. Alhoewel daar nie ernstige insekskade waargeneem is nie, was dit tog duidelik dat die bietjie vreetskade wat in die waterbehandelings voorgekom het, nie in die paraffienbehandelings voorgekom het nie. Dit dui aan dat die paraffien moontlik ‘n afwerende invloed gehad het. Paraffien het geen negatiewe invloed enigsins gehad op die groei en produksie van kanola in hierdie eksperiment nie. Hierdie studie dui aan dat verskillende gewasse verskillend reageer op saadbehandeling met paraffien. Die resultate van die vierde eksperiment dui aan dat paraffien moontlik as ‘n pesafweermiddel op sekere geselekteerde gewasse gebruik kan word maar meer navorsing word benodig op die onderwerp.

In der vorliegenden Studie haben wir mit Hilfe von SHARP-Screening, einer 16S-rRNA-basierten Heterogenitäts- und phylogenetischen Analyse, die mikrobielle Diversität in entzündlichen Lymphadenitiden ohne vorherige Kenntnis der jeweiligen Erreger an einer Serie von 15 Lymphknoten untersucht. Die Methode wurde erstmals auf diese Fragestellung angewandt. Sie konnte für die Verwendung von paraffineingebettetem Gewebe adaptiert werden, so dass auch Gewebeproben analysiert werden konnten, von denen kein Gefriermaterial zur Verfügung stand und die in Routineverfahren eingebettet und nach Standardmethoden gefärbt wurden. SHARP-Screening beinhaltet zwei komplementäre Schritte: Zuerst erfolgte die Erstellung einer Genbank aller bakteriellen Gene aus der gesamten extrahierten DNA des analysierten Gewebes durch gezielte Amplifikation des 16S-rRNA-Gens mittels universeller eubakterieller Primer. Als zweiter Schritt wurde nach der Transformation mittels Analyse des Restriktionsfragmentlängenpolymorphismus die Selektion der jeweiligen unterschiedlichen Phylotypen der enthaltenen 16S-rRNA-Gene durchgeführt (insgesamt 400). Nach der Sequenzierung wurden die 16S-rRNA-Gene durch den Vergleich mit bekannten bakteriellen Sequenzen mit Hilfe des „Basic-Local-Alignment-Search-Tool“ (BLAST) identifiziert. SHARP-Screening hat sich als geeignete Methode zur Analyse der gesamten, in einer Gewebeprobe enthaltenen bakteriellen Flora erwiesen. Dabei wurden zum Teil andere Erreger gefunden, als aus dem histologischen Bild vermutet wurden. So konnte zum Beispiel mit dem Nachweis von Gluconacetobacter sacchari, als potentieller Erreger einer septischen Granulomatose, eine alternative Differentialdiagnose zur histologisch vermuteten Katzenkratzkrankheit aufgezeigt werden. Darüber hinaus konnten auch gleichartige histologische Bilder bei dem gleichen identifizierten Erreger beobachtet werden. Zum Beispiel konnten im Zusammenhang mit dem Auftreten von Ödemen, Nekrosen, granulomatös eitrigen Veränderungen und einer ausgeprägten Sinus-histiozytose im Lymphknotengewebe immer wieder Comamonadaceae bzw. Janthinobacterium nachgewiesen werden. Oft zeigte sich nicht ein einzelner Erreger der Lymphadenitis, sondern ein ganzes Spektrum, wobei aus dem Vorhandensein der 16S-rRNA nicht auf das Vorhandensein vitaler Erreger geschlossen werden kann. Dennoch erlaubt die Häufigkeit der entsprechenden Klone eine semiquantitative Abschätzung der Bedeutung des jeweiligen Erregers. So wies SHARP-Screening auch Homologien zu Paracoccus yeeii nach. Eine Spezies, die mit klassischen Methoden häufig übersehen wird, die in Lymphknoten jedoch eine pathogene Rolle spielen kann. Im Zusammenhang mit dem histologischen Verdacht auf ein Malignom wurden in einigen Fällen Streptomyces, Roseomonas gilardii rosea und Stenotrophomonas maltophila nachgewiesen, die auch in der Literatur häufig bei immunsupprimierten Patienten vorkommen. Bei dem Verdacht auf ein Lymphgranuloma venerum wurde eine Cyanobacterium-Spezies detektiert, die es nach Literaturangaben Chlamydia trachomatis erst möglich macht, den eigenen Aminosäurestoffwechsel zu betreiben. Insgesamt dürften vom SHARP-Screening noch weitere tiefgreifende Erkenntnisse der bakteriellen Diversität und kausaler Erregerassoziationen in Erkrankungen des lymphatischen Systems zu erwarten sein. / The focus of this study was laid on the analysis of the microbial diversity in inflammatory lymphadenitis of 15 different lymph nodes without prior knowledge of the respective causative organism with help of the SHARP-Screening, a 16S-rRNA-based heterogeneity and phylogenetic analysis. This represents the first study to analyse this problem with the above mentioned SHARP-Screening adapting the method for the utilization of paraffin embedded tissue which consequently allowed the analysis of tissue specimen of which no freezing material was available and which were embedded in routine procedures as well as coloured according to a standard approach. The SHARP-Screening compromises two complementary steps: The first step is the creation of a gene pool of all bacterial genes of the entire DNA extracted from the analysed tissue by the systematic amplification of the 16S-rRNA-gene by means of universal eubacterial primers. The next step after the transformation was the selection of the different phylotypes of the incorporated 16S-rRNA-genes (altogether 400) by analysing the restriction fragment length polymorphism (RFLP). After the sequencing, the 16S-rRNA-genes were identified by comparing them with the known bacterial sequences with help of the “Basic-Local-Alignment-Search-Tool” (BLAST). The SHARP-Screening has proved itself as an adequate method to analyse the entire bacterial flora contained in the tissue sample. In some cases different causative organisms were found in contrast to the expectations which arose from the histological pictures. In this way evidence of gluconacetobacter sacchari could be provided as potential causative agents of a septic granulomatosis, an alternative differential diagnosis to the histologically assumed cat scratch disease. Furthermore, histological pictures of a similar type could be observed with regard to the same identified causative organism. For example, in conjunction with the appearance of edema, necrosis, granulomatosic purulent alterations and a very pronounced sinushistiozytosis in the lymph node tissue, comamonadaceae and accordingly janthinobacteria could consistently be demonstrated. A lot of times not just a single causative organism but a whole spectrum of the lymphadenitis could be identified. Here, however, the existence of the 16S-rRNA cannot be attributed to the existence of vital causative agents. Nevertheless, the frequency of the respective clones allows a semi quantitative assessment of the importance of the corresponding causative agents. Thus the SHARP-Screening proved evidence of homologies to paracoccus yeeii. A species which is often missed with classic methods however can play a pathogenic role. In several cases streptomyces, roseomonas gilardii rosea and stenotrophomonas maltophila, which are often mentioned in literature with regard to immunosuppressed patients, could be demonstrated in connection with the histological suspicion of a malignant tumour. While suspecting a lymphgranuloma venerum, a cyanobacterium species was discovered which according to literature sources enables chlamydia trachomatis to operate the body’s amino acid metabolism. Altogether, the SHARP-Screening is expected to lead to even more profound findings of bacterial diversity and causal causative organism associations with regard to diseases of the lymphatic system.

Les effluents pétroliers contiennent généralement des hydrocarbures lourds en faible quantité. Toutefois dans certains gisements, où les fluides sont stockés à des profondeurs importantes dans des conditions de pression et de température proches des conditions critiques, la proportion de composés lourds peut être significative et donc engendrer des modifications importantes des propriétés thermophysiques de ces fluides, particulièrement sur les équilibres de phases liquide - solide. En effet, suivant la proportion et la nature de la fraction lourde, la température de fusion peut s'élever de façon drastique. Ainsi la présence de composés lourds peut provoquer l'apparition de dépôts solides au sein des équipements d'exploitation ou dans les conduits de transport. La prévention de ces dépôts solides, qui constituent un risque important de détérioration du matériel, passe, en premier lieu, par la détermination précise des conditions d’apparition des premiers cristaux de paraffine au sein des fluides de gisement. Dans cette perspective, cette thèse a pour objectif principal le développement d’une méthode expérimentale d’observation des conditions de formation des cires au sein des huiles brutes ainsi que de leur évolution en fonction des conditions de température et de pression. Pour cela, une technique microscopique couplée à une analyse d’image novatrice est proposée. / Most of petroleum reservoir fluids contain a small amount of heavy hydrocarbons. However, in some deep oil reservoirs, in which fluids are stored under high pressure and high temperature conditions, the light components in supercritical state are able to dissolve a significant amount of high molecular weight components. The heavy components, which are soluble in crude oil under reservoir conditions, may precipitate as a waxy solid phase when temperature decreases below the cloud point. According to the nature and the quantity of heavy components, the wax appearance temperature may be high in some crude oils (higher than the water freezing point). In this case, due to a decrease in temperature or due to a modification of the composition of light components, wax deposition may occur during production or when oil is transported through pipelines across cold areas. Thus, the presence of heavy components in reservoir fluids constitutes a potential risk of plugging process equipment at different stages of exploitation. To prevent and to avoid paraffin deposition in pipelines, it is first required to determine the wax appearance conditions throughout the pressures encountered during production.To this end, the main objective of this thesis is the design and the development of a new experimental technique for determining visually the liquid-solid phase transitions in crude oils. This technique rests on a digital microscopic image analysis to detect the onset of wax precipitation and the evolution of waxy solid as a function of temperature and pressure.

Este estudo tem como objetivo a modificação da superfície de revestimentos poliméricos utilizando plasma, com o intuito de se criar materiais com superfícies resistentes a corrosão química e com baixa energia de superfície. Além disso, durante o trabalho foram estudadas diferentes maneiras de se viabilizar a aplicação em compartimentos de armazenamento e dutos de transporte de petróleo de modo a evitar a corrosão e diminuir a criação de depósitos de parafina e outras substâncias nas paredes dessas estruturas metálicas. Durante o projeto foi constatada a possibilidade de utilização dos processos estudados também em outras aplicações eletroquímicas, como por exemplo, a modificação da superfície de membranas seletivas. Portanto, a idéia geral do trabalho é a criação e modificação de materiais com características específicas para aplicações eletroquímicas, tendo como foco principal a proteção contra a corrosão e geração de filmes poliméricos com funções especiais. Para isso, foram estudadas a fluoração das superfícies de camadas poliméricas utilizando-se de um ambiente reativo de plasma, a deposição de filmes nanoestruturados sobre filmes poliméricos, e a avaliação de aplicações para os filmes desenvolvidos para redução da adsorção química. A partir dos resultados obtidos foi possível criar um revestimento que combina alta aderência à superfície do aço e baixa tensão superficial, devido à criação de uma camada com alta concentração de flúor. Os resultados mostraram-se promissores na modificação de revestimentos comerciais, pois apenas a superfície do revestimento anticorrosivo é alterada, utilizando-se uma quantidade pequena de reagentes e criando uma superfície antiaderente, e consequentemente, diminuindo a taxa de deposição da parafina no revestimento tratado. / The objective of this study is to modify the surface of polymeric coatings using plasma, with the aim of creating materials able to form low energy surface and chemical corrosion resistance. Moreover, in this work, was studied the application of the materials in storage compartments and pipelines transporting oil to check corrosion prevention and the reduction of paraffin deposits and other substances in the walls of these structures. Over the project it was found the possibility to use the studied processes in other electrochemical applications, such as the surface modification of selective membranes. So the general idea of this work is to create and/or modify materials with specific properties for electrochemical applications, focusing mainly on the corrosion protection and in the deposition of polymeric films with special functions. Thus, the fluorination of the polymeric layer surface using a reactive plasma environment, the deposition of nanostructured films on polymer films, and the performance evaluation for the films developed to reduce the chemical adsorption were studied. The results have shown that it is possible to develop a coating that combines high adhesion to steel surfaces and low surface tension, due to the creation of a layer with high concentration of fluorine. The processes were promising for modification of commercially available coatings, as only the surface is changed, only small amounts of reagents are used and an anti-adherent surface is created, which decreases the rate of paraffin deposition on the treated surface.

<p>This thesis explores the potential of multifunctional silicon-based microsystems for advanced integrated nanospacecraft (AIN). Especially, multifunctional microsystems with the coexistant functions of communications and thermal management implemented in multilayer silicon stacks are approached with systems study. Host vehicles, composed of microsystems, including micro/nano-spacecraft and spherical rovers are contemplated with respect to future performance and implications, system level design, and breadboard realizations. A module of great importance, named the "integrated communications and thermal management system for advanced integrated spacecraft" or ICTM, symbolizes the achievements within the field of self-contained microsystems and is a prioritized entity throughout the thesis. The ICTM is natively placable onboard all types of highly miniaturized craft.</p><p>The single AIN spacecraft and future clusters of these are investigated with respect to future full scale implementation of space systems designed and implemented with the distributed reconfigurable nanospacecraft cluster (DRNC) concept. Here, a true entanglement of microsystems technology (MST) and miniaturized spacecraft technology can revolutionize the applications, cost, and span of conceivable space missions.</p><p>An intended communications scenario supporting a data rate of 1 Mbps, for the transmitter, is achieved during 6 minutes with a maximum continuous power dissipation of 10 W. Thermal simulations support the expectation, of a thermally biased ICTM, that the module is capable of supporting this energy burst, by using the mechanisms of heat storage and heat switches, and still fulfilling the requirements imposed by AIN type of spacecraft. In addition, multiple functional surfaces for the ICTM are evaluated with respect to equilibrium temperature and process compatibility. The tailored surfaces provide temperature control using micromachining methods.</p><p>A design of a micromachined Ka-band front end with several MST enabled features is presented including e.g. vias, phase-shifters, and antennas. Similar antennas have been manufactured resulting in an evaluation of ring- and slot-antennas on silicon substrate. Based on a primitive version of the ICTM, a S-band patch antenna has been successfully implemented and characterized. Included in the thesis is a microthruster, an enabling technology for DRNC.</p>

Titel: Hudkrämer – vad innehåller de? Med fokus på barns hälsa och miljö.Syfte: Att undersöka vad råvarorna i två olika hudvårdsprodukter för barn utgörs av samt deras påverkan på huden och miljön.Bakgrund: Idag används 100 000 olika kemiska ämnen i produkter. Deras reglering är begränsad till dess enskilda effekter men ingen vet hur deras kombinerade verkan är eller hur många som konsumenter kommer i kontakt med. Vid allergier försvåras utredningen i sjukvården, om den alls är möjlig att göra, pga. den stora mängden av kemiska ämnen. Konsumentens möjlighet att göra ett miljövänligt val av hudvårdande produkter är begränsad. Hur produkterna påverkar miljön vid tillverkning och avfallshantering är en upplysning som ofta saknas.Metod: Litteraturstudie samt en jämförande undersökning av två olika hudvårdsprodukter.Resultat: Enligt undersökningen är innehållet i de båda hudkrämerna väsentligt olika. Råvarorna i Locobase kommer från den petrokemiska industrin medan råvarorna i Children body lotion kommer från vegetabiliska oljor och fetter. De enskilda ämnenas verkan på huden redovisas. Hur ämnena påverkar miljön vid framställning alternativt avfallshantering tas upp.Slutsats: Konsumenten har ett ansvar vad gäller spridningen av kemikalier och tydliga upplysningar bör finnas om produkternas innehåll och påverkan på miljön. Genom ökad kunskap om produkters innehåll samt en ny syn på konsumering av hudkrämer kan kemikalieanvändning liksom allergirisker minskas.