Beim Kolikpferd stellt der Einsatz von Laxantien den wesentlichen Teil der konservativen Behandlung primärer Obstipationen des Zäkums und großen Kolons dar. Um die Obstipation zu erreichen muss das über eine Nasenschlundsonde eingegebene Abführmittel den Magen verlassen und den Dünndarm passieren. Dabei soll das Flüssigkeitsvolumen möglichst vollständig im Intestinaltrakt verbleiben, um effektiv die Ingesta zu durchfeuchten und so die Obstipation zu lösen. Je nach Art und Konzentration des gewählten Laxans werden Resorptions- und Sekretionsvorgänge an der Darmschleimhaut ausgelöst, die sich als Elektrolytverschiebungen oder Alterationen des Wasserhaushaltes im Blut zeigen können. Ziel dieser Studie war es, beim gesunden Pferd einen Einfluss der am häufigsten eingesetzten Laxantien auf die Magenentleerungszeit zu ermitteln. Zudem sollten Auswirkungen auf den Elektrolyt- und Wasserhaushalte untersucht werden. Für die vorliegende Studie wurde sechs gesunden, nüchternen, adulten Warmblutpferden abwechselnd je eines von 5 Laxantien über eine Nasenschlundsonde in den nüchternen Magen eingegeben: 1,8% Natriumsulfatlösung (Protokoll 1); 4,2% Magnesiumsulfatlösung (Protokoll 2); Paraffinöl (Protokoll 3); 25% Natriumsulfatlösung (Protokoll 4); 25% Magnesiumsulfatlösung (Protokoll 5). Als Kontrolle wurde Wasser verabreicht: 10 L Wasser (Protokoll 6); 2 L Wasser (Protokoll 7). Zur indirekten Messung der Magenentleerung wurde der flüssige Passagemarker D-(+)-xylose (0,5 g/kg KG als 10% Lösung) jedem Protokoll zugefügt mit mindestens einer Woche Auswaschzeit zwischen den einzelnen Protokollen. Zu festgelegten Zeitpunkten wurden EDTA-Blut- und Serumproben aus der Jugularvene entnommen. Die Serumkonzentration von D-Xylose wurde colorimetrisch untersucht. Die Zeit bis zum Erreichen der maximalen Serumkonzentration von D-Xylose (Tmax) wurde als Magenentleerungszeit angesehen. Zur Einschätzung des Wasserhaushaltes wurden Totalprotein, Albumin und Hämatokrit bestimmt. Der Elektrolythaushalt wurde anhand der Serumkonzentrationen von Natrium, Kalium, Chlorid, Magnesium und Gesamtkalzium beurteilt. Zudem wurde der Einfluss auf die Wasseraufnahme und die Kotkonsistenz grobsinnlich untersucht. Ergebnisse dieser Studie zeigen, dass weder isotone Natriumsulfatlösung noch Paraffinöl die Magenentleerungszeit im Vergleich zu Wasser beeinträchtigen. Isotone Magnesiumsulfatlösung als auch hypertone Lösungen salinischer Laxantien führen zu einer signifikanten Verzögerung der Magenentleerung im Vergleich zu Wasser. Nach 10-stündiger Nahrungskarenz führte die Applikation von Wasser bei gesunden Pferden zum Abfall der Serumkonzentrationen von Natrium, Kalium, Magnesium, Gesamtkalzium und Chlorid. Isotone Lösungen von Natriumsulfat (1,8%) und Magnesiumsulfat (4,2%) führten nach einmaliger Applikation zum signifikanten Anstieg der Serumkonzentrationen von Natrium bzw. Magnesium innerhalb der Referenzbereiche. Paraffinum liquidum hatte keine starke Alterationen des Elektrolythaushaltes zur Folge. Hypertone Natriumsulfatlösung (25%) verursachte Hypernatriämie sowie einen signifikanten Abfall der Kalium- und signifikanten Anstieg der Chloridkonzentration. Hypertone Magnesiumsulfatlösung (25%) verursachte Hypermagnesämie sowie eine signifikante Abnahme der Kalium- und Gesamtkalziumkonzentration. Keines der verabreichten Laxantien führte zur Dehydratation. Alterationen der Wasseraufnahme oder der Kotkonsistenz wurden ausschließlich durch hypertone Natriumsulfatlösung verursacht, die die Wasseraufnahme deutlich steigerte und vorübergehend dünnbreiigen Kotabsatz induzierte. Bei primären Obstipationen des großen Kolons muss bis zur Lösung der Obstipation meist eine mehrmalige Applikation von Abführmitteln erfolgen. Hypertone Natrium- bzw. Magnesiumsulfatlösung erhöht die Serumkonzentration von Natrium bzw. Magnesium signifikant und könnte eine klinische Hypernatriämie bzw. Hypermagnesiämie erzeugen. Aus diesem Grund sind isotone Lösungen zu bevorzugen. Außerdem ist Kolikpferden mit primärer Dickdarmobstipation, die mit salinischen Laxantien behandelt werden, freier Zugang zu Wasser zu gewähren, um den entstehenden Durst der Pferde zu stillen. Zusammenfassend ist die Verabreichung isotoner Natriumsulfatlösung zu empfehlen, weil dieses effektive Laxans weder die Magenentleerungszeit verzögert, noch starke Elektrolytimbalanzen verursacht.:1 Einleitung ......................................................................................... 1 2 Ergebnisse........................................................................................ 5 2.1 Publikation 1: Influence of laxatives on gastric emptying in healthy Warmblood horses evaluated with the D-xylose adsorption test......... 5 2.2 Publikation 2: Einfluss von Laxantien auf den Wasser- und Elektrolythaushalt bei gesunden Pferden...-........................................ 21 3 Diskussion........................................................................................ 30 3.1 Untersuchungsmethoden der Magenentleerung........................... 30 3.1.1 D-Xylose..................................................................................... 30 3.2 Magenentleerungszeit.................................................................. 31 3.2.1 Wasser....................................................................................... 31 3.2.2 isotone Lösungen...................................................................... 32 3.2.3 hypertone Lösungen.................................................................. 32 3.2.4 Paraffinöl.................................................................................... 33 3.3 Elektrolythaushalt......................................................................... 34 3.3.1 Wasser....................................................................................... 34 3.3.2 isotone Lösungen...................................................................... 35 3.3.3 hypertone Lösungen.................................................................. 36 3.3.3.1 Natriumsulfat........................................................................... 36 3.3.3.2 Magnesiumsulfat..................................................................... 36 3.3.4 Paraffinöl.................................................................................... 38 3.4 Wasserhaushalt............................................................................ 39 3.5 Wasseraufnahme und Kotkonsistenz............................................ 39 4 Zusammenfassung........................................................................... 42 5 Summary........................................................................................... 44 6 Literaturverzeichnis.......................................................................... 46 Danksagung / The use of laxatives is crucial in the treatment of horses with cecal or large colon impaction. To reach the impacted mass, the laxative must leave the stomach and pass through the small intestine. The fluid volume should stay inside the gastro-intestinal tract to soften the intestinal contents and resolve the impaction. Depending on the type and concentration of the laxative, absorption and secretion can be triggered in the intestinal mucosa which might be shown as electrolyte abnormalities, or as alterations in the water balance in the blood. The aim of this study was to determine an influence of the most frequently used saline and lubricant laxatives on gastric emptying time in healthy horses. Furthermore the effect on electrolyte and water balance was to be investigated. Six healthy adult fasted Warmblood horses were used for this study which was performed with 5 laxatives, administered via nasogastric tube: 1.8% sodium sulfate (trial 1), 4.2% magnesium sulfate (trial 2), mineral oil (trial 3), 25% sodium sulfate (trial 4), 25% magnesium sulfate (trial 5). Water was used as control: 10 L water (trial 6), 2 L water (trial 7). For indirect measurement of gastric emptying the liquid passage marker D-(+)-xylose (0.5 g/kg bwt as 10% solution) was added to each trial with a minimum washout period of at least one week between the individual trials. EDTA blood and serum samples were taken from the jugular vein at predetermined time points. The serum concentration of D-xylose was analyzed colorimetrically. The time to reach peak serum concentration of D-xylose (Tmax) was considered as gastric emptying time. Total protein, albumin and PCV were chosen to evaluate water balance. Electrolyte balance was evaluated on the basis of the serum concentrations of sodium, potassium, chloride, magnesium and total calcium. Furthermore the impact on water uptake and fecal consistency was roughly examined. Isotonic solutions of sodium sulfate as well as mineral oil do not delay gastric emptying time compared to water. Isotonic solutions of magnesium sulfate as well as hypertonic solutions of saline cathartics significantly delay gastric emptying time in comparison to water. After ten hours of food restriction the administration of water decreased the serum concentrations of sodium, potassium, magnesium, total calcium and chloride in healthy horses. A single administration of isotonic solution of sodium sulfate (1.8%) or magnesium sulfate (4.2%) significantly increased serum sodium, respectively serum magnesium concentrations, within the reference range. Mineral oil did not alter electrolyte balance. Hypertonic solution of sodium sulfate (25%) caused hypernatremia, a significant decrease in potassium concentration and a significant increase in chloride concentration. Hypertonic solution of magnesium sulfate (25%) caused hypermagnesemia and a significant decrease in potassium and total calcium concentrations. None of the administered laxatives caused dehydration. Altered water uptake or fecal consistency was caused by hypertonic solution of sodium sulphate only, which considerably increased water consumption and transitionally induced runny feces. For treatment of simple large colon impactions, administration of laxatives usually has to be repeated, until the obstruction has resolved. Hypertonic solutions of sodium and magnesium sulfate significantly increase serum sodium or magnesium concentrations, respectively and may cause clinically hypernatremia or hypermagnesemia. Therefore isotonic solutions are preferable. Furthermore horses with simple large colon impaction, which are treated with saline cathartics need to have free access to water in order to satisfy their arising thirst. In summary it can be stated that the administration of isotonic solution of sodium sulfate is to be recommended, since this effective laxative does neither delay gastric emptying time nor leads to severe electrolyte alterations.:1 Einleitung ......................................................................................... 1 2 Ergebnisse........................................................................................ 5 2.1 Publikation 1: Influence of laxatives on gastric emptying in healthy Warmblood horses evaluated with the D-xylose adsorption test......... 5 2.2 Publikation 2: Einfluss von Laxantien auf den Wasser- und Elektrolythaushalt bei gesunden Pferden...-........................................ 21 3 Diskussion........................................................................................ 30 3.1 Untersuchungsmethoden der Magenentleerung........................... 30 3.1.1 D-Xylose..................................................................................... 30 3.2 Magenentleerungszeit.................................................................. 31 3.2.1 Wasser....................................................................................... 31 3.2.2 isotone Lösungen...................................................................... 32 3.2.3 hypertone Lösungen.................................................................. 32 3.2.4 Paraffinöl.................................................................................... 33 3.3 Elektrolythaushalt......................................................................... 34 3.3.1 Wasser....................................................................................... 34 3.3.2 isotone Lösungen...................................................................... 35 3.3.3 hypertone Lösungen.................................................................. 36 3.3.3.1 Natriumsulfat........................................................................... 36 3.3.3.2 Magnesiumsulfat..................................................................... 36 3.3.4 Paraffinöl.................................................................................... 38 3.4 Wasserhaushalt............................................................................ 39 3.5 Wasseraufnahme und Kotkonsistenz............................................ 39 4 Zusammenfassung........................................................................... 42 5 Summary........................................................................................... 44 6 Literaturverzeichnis.......................................................................... 46 Danksagung

Starting an engine in low temperatures creates unnecessary wear on components due to the insufficient lubrication of cold engine oil. A cold engine produces more emissions and consumes more fuel. Not all cars are equipped with engine heaters and installing an aftermarket heater is both expensive and time consuming. The aim with this project is to develop a universal engine heater with the ability to heat engine oil efficiently. Installing the engine heater should not require any special tools or expertise. To create a universal engine heater the construction is flexible similar to an electric cable and the length can be modified. The lower part, in contact with the engine oil, contains a resistor with an outside cover of steel to efficiently transfer heat. The challenge is to create an engine heater that is efficient in heating the engine oil while being small enough to fit in most cars. The surface area of the heater plays a large role when it comes to transfer heat efficiently. To heat 6 liters of engine oil from - 20 ° to -6° C takes roughly 2 hours with conventional surface area. By doubling the area by using another design, the same temperature can be reached in about 30 minutes. / Att starta en motor i minusgrader sliter mycket på invändiga komponenter. Detta då motoroljan på grund av högre viskositet inte smörjer lika bra, vilket i sin tur leder till att oljan inte kan cirkulera i motorn. Dessutom släpper en kall motor ut större mängder föroreningar i luften och förbrukar mer bränsle. Alla bilar är inte utrustade med motorvärmare och att eftermontera är både kostsamt och tidskrävande. Målet med projektet är att ta fram en universell motorvärmare med kapacitet att värma upp motoroljan i en personbil på ett effektivt sätt. Motorvärmaren ska inte kräva några speciella verktyg för att monteras och den ska vara lika lätt att montera som den ordinarie oljestickan. Motorvärmaren är konstruerad av ett elastiskt material likt en elsladd för att vara universellt passande. Den nedre delen i kontakt med motoroljan omsluter en resistor och har ett yttre hölje av stål för att ha god värmeöverföringsförmåga. Utmaningen är att konstruera en sticka som kan värma motoroljan tillräckligt snabbt och som är tunn nog att föras in i oljetråget utan hinder. En stor påverkande faktor gällande motorvärmarens prestanda är kontaktytan mellan motorvärmare och motorolja. Att värma upp 6 liter motorolja från -20 till -6° C tar drygt två timmar med oljestickans geometri. Med dubbla kontaktytan kan samma temperatur nås på drygt 30 minuter och denna areaändring kan ske genom att ändra motorvärmarens design.

In this paper numerical flow calculations with respect to the annular gaps with added radial grooves normaly used on the spools of directional control valves were carried out. The impact of various annular gap geometries and radial grooves during variable pressure conditions, and while using different hydraulic fluids, on the flows through annular gaps were investigated for different flow regimes. Samples with different geometries and numbers of radial groves on the spool of the directional control valve were also made for the purpose of carrying out flow measurements. The two different hydraulic fluids that were used in the numerical simulations and for the flow measurements were a hydraulic mineral oil and tap water. The results of the numerical calculations for the different models of the radial grooves with axially symmetric geometries show their impact on the internal leakage with respect to three different regimes of flow. The results of the numerical calculations based on the use of a hydraulic oil show a trend that was established by the experimental investigation.

In this paper numerical flow calculations with respect to the annular gaps with added radial grooves normaly used on the spools of directional control valves were carried out. The impact of various annular gap geometries and radial grooves during variable pressure conditions, and while using different hydraulic fluids, on the flows through annular gaps were investigated for different flow regimes. Samples with different geometries and numbers of radial groves on the spool of the directional control valve were also made for the purpose of carrying out flow measurements. The two different hydraulic fluids that were used in the numerical simulations and for the flow measurements were a hydraulic mineral oil and tap water. The results of the numerical calculations for the different models of the radial grooves with axially symmetric geometries show their impact on the internal leakage with respect to three different regimes of flow. The results of the numerical calculations based on the use of a hydraulic oil show a trend that was established by the experimental investigation.

<p>U radu je izvr&scaron;ena karakterizacija sirove (povr&scaron;inske) vode na lokalitetima: akumulaciono&nbsp;jezero, nizvodna deonica do izvori&scaron;ta namenjenog za vodosnabdevanje, na lokalitetu samog izvo-ri&scaron;ta i na ulazu u poluindustrijsko istraživačko postrojenje. Ustanovljene su sledeće karakteristike&nbsp;sirove vode: eutrofne karakteristike akumulacionog jezera u vremenskom periodu od kraja juna do&nbsp;sredine septembra meseca; fekalna zagađenost deonice od akumulacionog jezera do izvori&scaron;ta na-menjenog za vodosnabdevanje; veliki raspon temperature u toku godine (4-19&ordm;C); niske vrednosti&nbsp;mutnoće vode u najvećem delu godine uz povremen i kratkotrajan izrazit porast ovog parametra&nbsp;(&lt;1 NTU do &gt;90 NTU); promena sadržaja organskih materija u vodi (izraženih preko potro&scaron;nje ka-lijum-permanganata u kiseloj sredini i UV apsorbancije na 254 nm); izražen potencijal za formira-njem nusprodukata dezinfekcije (THM) u toku obilnih padavina.&nbsp;<br />Na poluindustrijskom istraživačkom postrojenju izvr&scaron;eno je ispitivanje različitih tehnolo&scaron;kih vari-janti pripreme vode za piće iz povr&scaron;inske vode namenjene vodosnabdevanju uz primenu savreme-nih tehnolo&scaron;kih re&scaron;enja i adekvatnog tretmana u slučaju ekscesa izazvanih ljudskom aktivno&scaron;ću.&nbsp;Primenjenim tretmanom vode procesima ozonizacije-koagulacije-flokulacije-sedimentacije-filtra-cije na poluindustrijskom istraživačkom postrojenju zadovoljena je primarna funkcija redukcije&nbsp;opterećenja vode pre odlaska na zavr&scaron;no bistrenje procesom filtracije. Ustanovljeni su najvažniji&nbsp;faktori uticaja na mutnoću vode nakon primenjenih procesa: vrsta koagulanta (najbolji efekti po-stignuti primenom Al₂(SO₄)_3&nbsp;i FeCl₃) i primenjena doza ozona (pozitivan, mikroflokulacioni efekat ozona postignut pri primenjenim dozama ozona od 0,5-1,0 mgO₃/l). Izračunato je da su pri primeni Al₂(SO₄)_3&nbsp;kao koagulacionog sredstva dvomedijumski filteri namenjeni zavr&scaron;nom bistrenju vode imali najduži filtracioni ciklus. Srednje vrednosti količine uklonjene mutnoće su 2,5- 3,5 puta veće u odnosu na ove vrednosti dobijene pri primeni ostalih koagulanata u fazi koagulacije vode. Značaj primenjenog procesa ozonizacije (doze ozona) uočen je i sa aspekta smanjenja sadržaja prekursora formiranja THM.</p><p>Ispitivanjem efekta predtretmana vode procesom ozonizacije, primenom vodonik-peroksida i ko-mercijalnog preparata koji u svom sastavu sadrži 25% H₂O_2&nbsp;+ 0,05% Ag u ozoniranu vodu u cilju&nbsp;redukcije broja mikroorganizama uočeni su pozitivni efekti na log_10&nbsp;inaktivacije pri dozama ozona&nbsp;&gt;0,5 mgO₃/l (u slučaju sporogenih sulfitoredukujućih klostridija) i vi&scaron;ih vrednosti odnosa H₂O₂/O_3&nbsp;i H₂O₂+Ag/O_3&nbsp;(u slučaju ukupnog broja aerobnih organotrofnih bakterija). Prednost primene preparata koji u svom sastavu sadrži 25% H₂O_2&nbsp;+ 0,05% Ag u ozoniranu vodu ogleda se u većem kapa-citetu eliminacije mikroorganizama i pri kraćem hidrauličkom vremenu zadržavanja vode.&nbsp;</p><p>Analizom frekvencije pojavljivanja jedinjenja koje prouzrokuje nepoželjan miris vode (geosmin)&nbsp;nakon primenjenih procesa ozonizacije-koagulacije-flokulacije-sedimentacije-filtracije ustanovljena je najmanja frekvencija pojavljivanja ovog jedinjenja (10% od ukupnog broja analiziranih uzo-raka) u vodi nakon procesa ozonizacije i njegova potpuna redukcija primenom koagulanta FeCl_3&nbsp;u&nbsp;fazi koagulacije vode.<br />Pri simulaciji ekscesnih situacija na poluindustrijskom istraživačkom postrojenju (doziranjem sintetičkih organskih jedinjenja pesticida i nafte) utvrđeno je da se primenom procesa ozonizacije-koagulacije-flokulacije-sedimentacije-filtracije uz dodatak AUP u fazi koagulacije vode postiže reduk-cija lindana u vodi za 97%, atrazina 99%, ukupnih ugljovodonika 91% i mineralnih ulja 89%.<br />Svi rezultati dobijeni u toku istraživanja na poluindustrijskom istraživačkom postrojenju posmatra-ni sa aspekta optimizacije tehnolo&scaron;kih uslova pripreme vode za piće i varijabilnog kvaliteta povr&scaron;in-ske vode ukazuju na prvom mestu na neophodnost primene procesa ozonizacije vode i pozitivan&nbsp;efekat unapređenih procesa oksidacije u fazi pripreme vode za dalju obradu, kao i na značaj primenjene vrste koagulanta i aktivnog uglja u prahu u fazi koagulacije i flokulacije vode.</p> / <p>The paper presents the characterisation of raw (surface) water at the following sites: accu-mulation lake, downstream section from the water supply well field at the very site of the well field&nbsp;and at the entrance into pilot plant. The following raw water characteristics have been determined:&nbsp;eutrophic properties of accumulation lake within the time frame from the end of June to the middle&nbsp;of September; faeces pollution of the section from the accumulation lake to the water supply well&nbsp;field; a wide range of temperature during the year (4-19&ordm;C); low values of water turbidity during the&nbsp;largest part of the year, with occasional and short-term emphasised growth &nbsp;of this parameter (&lt;1NTU to &gt;90 NTU); change in the content of natural organic matters in water (expressed through&nbsp;potassium permanganate consumption in acid environment and UV absorption at 254 nm); ex-pressed potential for disinfection by-products (THM) creation during high rainfall levels.</p><p>Study of different technological options for drinking water preparation from surface water desig-nated to water supply with application of the latest technological solutions and adequate treatment in cases of accidents caused by human activities has been carried out at the pilot plant.</p><p>The water treatment composed of ozonation-coagulation-flocculation-sedimentation-filtration applied at the pilot plant satisfied the primary function of reduction of water load prior to departure&nbsp;to the final clarification in filtration process. The most significant factors affecting water turbidity&nbsp;after the applied processes have been determined: type of coagulant (the best effects have been ob-tained by application of Al₂(SO₄)_3&nbsp;and FeCl₃) and the applied ozone dose (positive, micro-floccula-tion effect of ozone has been obtained with the applied ozone doses of 0,5-1,0 mgO₃/l). It has been&nbsp;calculated that two-media filters designated to final water clarification had the longest filtration cy-cle when Al₂(SО₄)_3&nbsp;was used&nbsp;as coagulation means. Medium values of quantity of the eliminated tur-bidity are 2,5-3,5 times higher in comparison to &nbsp;these values obtained when others coagulants were&nbsp;used in the water coagulation phase. The significance of the applied ozonization process (ozone&nbsp;dose) has also been found from the aspect of reduction of THM generation precursor contents.&nbsp;<br />Investigation of effects of water pre-treatment with ozonation process and application of hydrogen-peroxide and commercial preparation containing 25% H₂O_2&nbsp;+ 0,05% Ag in ozonized water aiming at&nbsp;reduction of micro-organisms count showed positive effects on log_10&nbsp;inactivation when &gt;0,5 mgO₃/l&nbsp;doses of ozone were used (in case of sulphito-reducing clostridia) and higher values of H₂O₂/O_3&nbsp;and&nbsp;H₂O₂+Ag/O_3&nbsp;ratio (in case of total aerobic organotrophic bacteria count). The advantage of appli-cation of the preparation containing 25% H₂O_2&nbsp;+ 0,05% Ag in ozonized water is reflected in higher&nbsp;microorganisms elimination capacity and shorter hydraulic retention time.&nbsp;<br />The analysis of occurrence frequency of compounds causing unpleasant water odour &nbsp;(geosmin) af-ter the applied ozonation-coagulation-flocculation-sedimentation-filtration processes showed that&nbsp;the lowest occurrence frequency for this compound (10% of the total number of the analysed sam-ples) in water after ozonisation process &nbsp;and its total reduction after the application of FeCl_3&nbsp;coagu-lant in water coagulation phase.<br />In simulation of accidents at pilot plant (dosing of synthetic organic compounds of pesticides and&nbsp;oil) it was found that reduction of lindane in water for 97%, atrazine for 99%, total hydrocarbons for&nbsp;91% and mineral oils for 89% is accomplished with application of the ozonation-coagulation-floccu-lation-sedimentation-filtration processes with addition of AUP in the phase of water coagulation.&nbsp;All the results that have been obtained during the researches at pilot plant have been considered&nbsp;from the aspect of optimisation of technological conditions of drinking water preparation and vari-able surface water quality point primarily to the necessity of application of water ozonization proc-ess and positive effect of the improved oxidation processes in the phase of water preparation for&nbsp;further processing as well as to the significance of the applied type of coagulant and active powder&nbsp;charcoal in water coagulation and flocculation phase.</p>

O objetivo desse trabalho foi de fazer a modelagem por meio de sistemas de inferência fuzzy da concentração dos gases dissolvidos em óleo mineral isolante à partir dos resultados de ensaios físico-químicos. Dessa forma, objetivou-se estender as técnicas de identificação de falhas em transformadores por meio da análise dos ensaios físico-químicos do óleo isolante. Para tanto adotou-se um mapeamento entre os dados de ensaios físico-químicos e de cromatografia gasosa feito por meio de sistemas de inferência fuzzy. Assim, por meio de resultados de ensaios físico-químicos, como cor, densidade, unidade, entre outro, tem-se uma estimativa da concentração dos gases dissolvidos no óleo mineral isolante do transformador. Assim, torna-se possível empregar técnicas de identificação de falhas baseadas na concentração dos gases dissolvidos, mas, valendo-se dos dados de ensaios físico-químicos.O sistema proposto foi validado por meio de dados reais e os resultados alcançados são compatíveis com aqueles obtidos por meio das técnicas convencionais. / The objective of this work was to do a modeling using the inference fuzzy system of the concentration of dissolved gases in insulating mineral oil getting from the physical-chemical results. The idea was to understand the techniques to identify failures on transformers by analyzing the physical-chemical results of the insulating mineral oil.To do that, the data from physical-chemical results and chromatographic results was mapped using the inference fuzzy system. So, by the results of the physical-chemical experiment such as color, density, humidity and so on, its possible to have a estimation of the concentration of dissolved gases in insulating mineral oil. Therefore, its possible to implement techniques to identify failures based on the concentration of dissolved gases using physical-chemical techniques.The propose system was validated by real data. The results using physical-chemical techniques were similar with the results using conventional techniques.

O objetivo desse trabalho foi de fazer a modelagem por meio de sistemas de inferência fuzzy da concentração dos gases dissolvidos em óleo mineral isolante à partir dos resultados de ensaios físico-químicos. Dessa forma, objetivou-se estender as técnicas de identificação de falhas em transformadores por meio da análise dos ensaios físico-químicos do óleo isolante. Para tanto adotou-se um mapeamento entre os dados de ensaios físico-químicos e de cromatografia gasosa feito por meio de sistemas de inferência fuzzy. Assim, por meio de resultados de ensaios físico-químicos, como cor, densidade, unidade, entre outro, tem-se uma estimativa da concentração dos gases dissolvidos no óleo mineral isolante do transformador. Assim, torna-se possível empregar técnicas de identificação de falhas baseadas na concentração dos gases dissolvidos, mas, valendo-se dos dados de ensaios físico-químicos.O sistema proposto foi validado por meio de dados reais e os resultados alcançados são compatíveis com aqueles obtidos por meio das técnicas convencionais. / The objective of this work was to do a modeling using the inference fuzzy system of the concentration of dissolved gases in insulating mineral oil getting from the physical-chemical results. The idea was to understand the techniques to identify failures on transformers by analyzing the physical-chemical results of the insulating mineral oil.To do that, the data from physical-chemical results and chromatographic results was mapped using the inference fuzzy system. So, by the results of the physical-chemical experiment such as color, density, humidity and so on, its possible to have a estimation of the concentration of dissolved gases in insulating mineral oil. Therefore, its possible to implement techniques to identify failures based on the concentration of dissolved gases using physical-chemical techniques.The propose system was validated by real data. The results using physical-chemical techniques were similar with the results using conventional techniques.

Abstract. Transformer explosions caused by dielectric failure account for over 50% of the disasters. The aim of this thesis is to examine, compare and outline the differences, in function, as dielectric insulators, vegetables oil has, with respect to the mineral oil used in high-power transformers. We will first consider the vegetable oil which has less dielectric capabilities than the mineral oil used in power transformers. Later in the experiments, we will focus mainly to examine the breakdown voltage property, as we try to alter some properties of the respective oils used. Considering the fact that vegetable oil has low viscosity, with its chemical compounds constituting less molecular masses compared to mineral oil, we endorse, from our experimental findings, that mineral oil is indeed worthy and reasonable to be used as a dielectric in high power transformers. In this write-up, we have considered eleven transformer oil properties. In the experiment proper, we considered only the acidity, whose concentration in the transformer oil increases with aging if the transformer, moisture, and a ‘suitable’ impurity like NaOH(aq). At first glance, one would be tempted to think, as we were, that since the increase in acid content of the oil deteriorates its dielectric performance, an increase in alkaline content of the transformer oil, would increase its dielectric ability; reversing the acid effect. But as we see in the results from our experiments, this is false. We think that the visible degradation of the insulating property of the oil, with the introduction of NaOH(aq), is because it acts as an impurity to suitable dielectric function. From the experiments, the heating procedures resulted in the production of toxic gases. This indicated the actual loss of chemical structure and significant breakage of chemical bonds. The resulting chemical composition of the oil does not produce the same dielectric properties as the initial oil sample. Also, here has been considerable inconsistency in the addition of NaOH(aq) or HCl(aq) to both oils. We only added HCl(aq), before every measurement, in two of the experiments. The other experiments were either with moisture, or a single addition of 2cm3 of either HCl(aq) or NaOH(aq) before heating; after which several measurements were taken, at specific intervals, as the mixture cools. We did so, in the latter, in which we had only one addition of a 2cm3 chemical, because in real life, given the short time frame of the experiment, the total amount of acid in the oil has a negligible change. So, in a functioning heated transformer, within a short time frame, there is actually deterioration in oil insulation properties

Ce travail porte sur la caractérisation physico-chimique de l'huile de Jatropha Curcas et sa capacité à remplacer l'huile minérale dans les transformateurs de puissance. Ce produit présente plusieurs avantages sur les autres huiles végétales comme l'huile de palme ou l'huile de colza, qui recommandent sa production et son utilisation. En effet, la plante de Jatropha Curcas peut être cultivée sur des sols pauvres à faibles précipitations, évitant ainsi d'utiliser des sols plus fertiles pour sa culture permettant ainsi aux petits exploitants de réserver leurs terres aux cultures de base. Cette plante peut pousser facilement dans des zones où les niveaux de précipitations annuelles sont nettement inférieures à celles requises par d'autres espèces telles que le colza, le tournesol, le soja, le maïs, le palmier à huile et d'autres. Elle peut être cultivée sur tous les types de sol en Indonésie, même sur des terres arides, dans de nombreuses régions de l'Indonésie orientale, inexploitées en raison des difficultés à planter d'autres cultures. En outre, l'huile de Jatropha Curcas est un produit non alimentaire. En faisant subir à l’huile de Jatropha Curcas brute une estérification à base alcaline avec de l'hydroxyde de potassium (KOH), on obtient de l’huile de méthylester de Jatropha Curcas (JMEO) dont la viscosité et l’acidité sont acceptables pour les équipements à haute tension en particulier pour les transformateurs de puissance. Les propriétés physico-chimiques et électriques de JMEO ont été mesurées ainsi que celles de l'huile minérale (MO) pour la comparaison. Pour les propriétés physico-chimiques, il s’agit de la densité relative, la teneur en eau, la viscosité, l'acidité, l'indice d'iode, la corrosivité, le point d'éclair, le point d'écoulement, la couleur, l'examen visuel, et la teneur en ester méthylique. Quant aux propriétés électriques, elles concernent la rigidité diélectrique sous différentes formes de tension (alternative, continu et choc de foudre), les phénomènes de pré-claquage et de claquage sous choc de foudre, les décharges glissantes sur les surfaces de carton comprimé, immergé dans JMEO et MO. Les résultats obtenus montrent que les tensions de claquage moyennes en continu et en choc de foudre des huiles JMEO et MO sont très proches ; la tension de claquage moyenne de JMEO est même plus élevée que celle de l'huile minérale (de type naphténique). La mesure des tensions de claquage des mélanges d'huiles «80% JMEO + 20% MO» et «50% JMEO et 50% MO» montrent que la tension de claquage du mélange «80% JMEO + 20% MO» est toujours supérieure à celle de l'huile minérale sous tensions alternative et continue. Cela indique que le mélange d'huile minérale et de JMEO avec un rapport de 20:80 ne dégrade pas ses performances. Le mélange d'huiles peut se produire lors du remplacement de l'huile minérale par JMEO dans les transformateurs installés et en exploitation. L'analyse des caractéristiques des streamers (la forme, le temps d'arrêt, le courant associé et la charge électrique) se développant dans les huiles JMEO et MO sous tension impulsionnelle de foudre, montre une grande similitude. Aussi, la longueur finale (Lf) et la densité des branches des décharges surfaciques se propageant sur le carton comprimé immergé dans l'huile de Jatropha Curcas de méthylester (JMEO) et de l'huile minérale (MO), sous tensions de choc de foudre positif et négatif (1,2/50 μs), pour deux configurations d'électrodes divergentes (électrode pointe haute tension perpendiculaire et tangente au carton, respectivement), sont fortement influencées par l'épaisseur du carton comprimé. Pour une épaisseur donnée, Lf augmente avec la tension et décroît lorsque l'épaisseur augmente. Lf est plus long lorsque la pointe est positive que lorsque la pointe est négative. Pour une tension et une épaisseur du carton comprimé donnée, les valeurs de Lf dans l’huile minérale et l’huile JMEO sont très proches. [...] / This work is aimed at the investigation of the physicochemical characterization of Jatropha Curcas seeds oil and its capacity to be an alternative option to replace mineral oil in power transformers. This product presents several advantages that recommend both its production and usage over those of other vegetable oils as crude palm oil and rapeseeds oil. Indeed, it may be grown on marginal or degraded soils avoiding thus the need to utilize those more fertile soils currently being used by smallholders to grow their staple crops; and it will readily grow in areas where annual rainfall levels are significantly lower than those required by other species such as palm oil, rape-seeds oil, sunflower oil, soybeans oil, corn oil and others. For instance, these plants can grow on all soil types in Indonesia, even on barren soil. The barren soil types can be found in many parts of eastern Indonesia that remain untapped because of the difficulty planted with other crops. Moreover, jatropha curcas oil is nonfood crops. Jatropha Curcas oil was processed by alkali base catalyzed esterification process using potassium hydroxide (KOH) to produce Jatropha Curcas methyl ester oil (JMEO) has a viscosity and a acidity that are acceptable for high voltage equipment especially in power transformer. The physicochemical and electrical properties of JMEO were measured as well as those of mineral oil (MO) for comparison. The physicochemical properties cover relative density, water content, viscosity, acidity, iodine number, corrosivity, flash point, pour point, color, visual examination, and methyl ester content. Meanwhile the electrical properties cover dielectric strength under AC, DC and lightning impulse voltages, pre-breakdown / streamers under lightning impulse voltage, creeping discharge over pressboard immersed in JMEO and MO. The obtained results show that the average DC and lightning impulse breakdown voltages of JMEO and MO are too close, even the average AC breakdown voltage of JMEO are higher than that of mineral oil (napthenic type). The measurement of breakdown voltages of two oil mixtures namely “80% JMEO + 20% MO” and “50% JMEO and 50% MO” shows that the breakdown voltage of the first mixture (i.e., “80%JMEO+20%MO”) is always higher than that of mineral oil under both AC and DC voltages. This indicates that mixing 20:80 mineral oil to JMEO ratio does not degrade its performance. The mixing of oils can occur when replacing mineral oil by JMEO in installed transformers. The analysis of the streamers characteristics (namely; shape, stopping length, associated current and electrical charge) developing in JMEO and MO under lightning impulse voltages, shows that these are too close (similar). It is also shown that the stopping (final) length Lf and the density of branches of creeping discharges propagating over pressboard immersed in Jatropha Curcas methyl ester oil (JMEO) and mineral oil (MO), under positive and negative lightning impulse voltages (1.2/50 μs), using two divergent electrode configurations (electrode point perpendicular and tangential to pressboard), are significantly influenced by the thickness of pressboard. For a given thickness, Lf increases with the voltage and decreases when the thickness increases. Lf is longer when the point is positive than with a negative point. For a given voltage and thickness of pressboard, the values of Lf in mineral oil and JMEO are very close. It appears from this work that JMEO could constitute a potential substitute for mineral oil for electrical insulation and especially in high voltage power transformers.

Transformers are the most expensive and critical asset in any electrical power network. Their failure results in long interruption of power supply with consequent loss of reliability and revenue. Understanding and detection of the failure mechanism helps in avoiding catastrophic failures, unplanned outages and improving the power system reliability. Oil impregnated paper (OIP) and pressboards form the main soild insulation in a transformer. Life of the transformer is governed mostly by the life of OIP insulation. Until recently, it was thought that ageing of the OIP insulation in power transformer and its eventual failure, is mainly a function of temperature and electrical stresses. However, it has now been realized that the moisture causes rapid degradation of OIP and needs a special attention. Considering its practical relevance, this research program was formulated with goals: (i) to study the ageing of OIP insulation under temperature and moisture stresses, (ii) to seek correlation between diagnostic ageing indices and end-of-life (EOL) and (iii) to develop a life model for OIP considering moisture along with the thermal stress. Observing that working with actual transformers or even the prototypes are rather inordinately expensive, experiments were conducted with paper strips immersed in oil in test tubes with paper to oil ratio kept same as that in power transformers. In order to cater for the statistical nature of the phenomena, adequate numbers of test specimens were employed (25 numbers for each experiment). Experiments were conducted for two years at temperatures 90°C, 110°C & 120°C and moisture 1%, 2% & 3%. Following the literature, the degree of polymerization (DP) was chosen as the primary index for ageing. As measurement of DP is not only destructive, but also impractical on most of the working transformers, with an aim to develop suitable diagnostic indices for ageing, 2-furfural (2-FAL) and oxides of carbon (CO and CO2) were also measured. Empirical relation between ageing and amount of stresses and time have been deduced for the relevant range. Limiting value of these indices to prescribe the end-of-life, as well as, their correlation with DP have been worked out and reported. In order to bring the role of moisture explicitly, based on earlier work on multi-stress ageing, a multiplicative power law supplementing the Arrhenius factor is envisaged. Accordingly, a phenomenological combined stress model involving the time to failure, temperature, and moisture content is deduced. Based on the experimental results, this model is statistically validated and the values of parameters appearing in the model is obtained. Thus the combined stress model enables one to estimate the life of OIP insulation at any temperature and moisture under synergy. In summary, this work through experimental and analytical approach has contributed to the evaluation of the aging of OIP insulation used in power transformers under the combined action of moisture and temperature.