Humidification Processes in Gas Turbine Cycles

The global climate change caused by emissions of greenhouse gases from combustion processes has been recognized as a continuously growing problem and much research focuses on improving the environmental performance of gas turbines. The potential of improving gas turbine component efficiencies has become smaller each decade and therefore, thermodynamic cycles have become more interesting for power producing units. One of these cycles is the evaporative gas turbine cycle, also known as the humid air turbine. This thesis presents a theoretical model developed for the humidification tower in an evaporative gas turbine. The developed theoretical model has been validated with measurements from experiments conducted in a 600 kWe pilot plant. This thesis presents the installation of a plate heat exchanger in the pilot plant. The experience from the pilot plant is used in a comparative study. This study evaluates the influence of the aftercooler on the performance of the evaporative gas turbine. A test facility for evaporation processes at elevated pressures and temperatures have been built. Evaporation of binary mixtures into a compressed air stream has been performed. Experimental studies with the pilot plant have revealed that it is possible to use a plate heat exchanger as aftercooler in the evaporative gas turbine. The pressure drop on the air side in the aftercooler has been experimentally determined to 1.6% and the pinch-point to 0.1°C. The reconstruction of the pilot plant from a simple cycle to an evaporative cycle has resulted in an increase in thermal efficiency from 21% to 35%. A theoretical model has been developed for the humidification process that predicts the height of the humidification column with an error of 10?15%. Thermodynamic analysis of the bio-EvGT has been performed which have showed that the bio-EvGT cycle has an optimum efficiency of 34%. Further thermodynamics analysis has indicated that the bio-EvGT is a viable alternative to the biomass fueled steam turbine cycle

Always and never the same: Women\u27s long-distance friendships during life course transitions

Various challenges can threaten the security of personal relationships, but one of the most difficult problems to manage is geographic distance. As more people live apart from someone about whom they care, the prevalence of long-distance relationships will increase. However, research on how long-distance friendships are characterized and accomplished lags behind. Therefore, the present study was designed to uncover how women define and maintain their long-distance friendships. A total of 34 interviews were conducted with first-year undergraduate students, first-year graduate students, and recently-hired faculty members at a large university. The interview transcripts were analyzed inductively, which resulted in the creation of nine categories. These were eventually reduced to six maintenance behaviors: openness, assurances, positivity, joint activities, personal networks, and mediated communication. Participants also challenged definitions of long-distance friendship based upon geography and replaced them with definitions based upon communication (access to interaction, use of mediated communication, level of closeness, and a commitment to expend the necessary time and energy to make it work). Although long-distance friendships may require more effort and involve more mediated communication, this study demonstrates that long-distance friends rely on similar maintenance behaviors as geographically-close friends. This indicates that long-distance friendships may not be as dramatically different or as perplexing as commonly thought. Overall, the present study reveals that long-distance friendships can be satisfying and maintained successfully, which challenges both cultural assumptions and traditional social science research. Many long-distance friendships are well-equipped to weather both changes and challenges, making them flexible, not fragile

Geological Histories from 4372 Ma to 26 Ma Recorded in Siliciclastic Metasedimentary Rocks from the Central Yilgarn Craton

This study presents an investigation of detrital, metamorphic, and hydrothermal minerals from siliciclastic metasedimentary rocks of the Illaara and Maynard Hills greenstone belts, central Yilgarn Craton. This research assesses how 4.3 to 3.0 Ga detrital zircon populations came to be found in dispersed metasedimentary rocks, how these rock occurrences relate to each other and what this may reveal about the early Earth and the formation of the Yilgarn Craton

Non-conventional working fluids for thermal power generation: A review

New technology requirements derived from the exploitation of novel energy resources, and the needs for improvement of the energy efficiency of current power generation systems are pushing the industry towards the search of alternative working fluids. The great challenge for these non-conventional fluids is to provide satisfactory performances and fill the existing lack of media for some innovative energy applications. In this review a number of emerging working fluids for thermal power generation are presented. Also, a special emphasis is devoted to the discussion about new promising fluids, such as nanofluids or ionic liquids, that could be an important breakdown for power generation in the near future

Ubiquitous Computing in a Home Environment, Controlling Consumer Electronics

Building interaction prototypes for ubiquitous computing is inherently difficult, since it involves a number of different devices and systems. Prototyping is an important step in developing and evaluating interaction concepts. The ideal prototyping methodology should offer high fidelity at a relatively low cost. This thesis describes the development of interaction concepts for controlling consumer electronics in a ubiquitous computing home environment, as well as the setup, based on immersive virtual reality, used to develop and evaluate the interaction concepts. Off-the-shelf input/output devices and a game engine are used for developing two concepts for device discovery and two concepts for device interaction. The interaction concepts are compared in a controlled experiment in order to evaluate the concepts as well as the virtual reality setup. Statistically significant differences and subjective preferences could be observed in the quantitative and qualitative data respectively. Overall, the results suggest that the interaction concepts could be acceptable to some users for some use cases and that the virtual reality setup offers the possibility to quickly build interaction concepts which can be evaluated and compared in a controlled experiment

Alcohol-related health problems and crime : studies on the long-term consequences of increased alcohol availability and unemployment

Background: The well-being of young people with respect to health and life opportunities is of high importance in society. This thesis examines the long-term adverse consequences of two periods in Sweden marked by high vulnerability for young people; one period with a drastic increase in alcohol availability for young people and one period with exceptionally high youth unemployment. Research has demonstrated immediate beneficial effects of restricting alcohol availability among adolescents and young adults. Less is known about the long-term consequences of exposure to increased alcohol availability during adolescence for the individual’s themselves and the health and well-being of subsequent generations. Evidence suggests that youth unemployment is related to worse self-reported mental and physical health in the long-term. There remains a discussion in the literature regarding the effect of prior poor health and contextual influences on the association, especially in relation to youth unemployment.: Aim: The aim of this PhD thesis was therefore to investigate the potential effects of exposure to increased alcohol availability during adolescence and in utero on disability pension (Study I), alcohol-related health problems (Study II) and criminal behavior (Study III). This thesis also aimed at investigating the effects of youth unemployment on mental health during periods of high and low unemployment rates and to explore whether there was any interaction in mental health between labor force status and levels of unemployment in society (Study IV). Methods: Studies I to III were register-based population-based longitudinal studies using a natural experiment setting of an alcohol policy experiment. During the late 1960s, strong beer became available in regular grocery stores in two regions of Sweden for adolescents under the age of 21 years, instead of being available only in the state-owned monopoly store “Systembolaget” with an age limit of 21 years. Study I investigated the effect of exposure to increased alcohol availability during adolescence on disability pension compared with same- aged unexposed adolescents (age 14–20 years). Studies II and III focused on the long-term effects of increased alcohol availability on children in utero during the time of the alcohol policy experiment. Study IV was a register-linked population-based cohort study based on individuals who had completed the nationwide Labour Force Survey between the ages of 17– 24 years at times of high or low national unemployment rates. Results: An increased risk of being granted disability pension due to an alcohol use disorder and a mental disorder was found among adolescents exposed to increased alcohol availability. No consistent evidence of any long-term consequences in subsequent generations was found. However, a slightly increased risk of alcohol-related health problems later in life was observed among exposed children conceived by young mothers. The results from Study IV showed a positive association between youth unemployment and mental health problems, irrespective of the overall national level of unemployment. Conclusion: Exposure to increased alcohol availability during adolescence can have long-term health consequences, for both the individual and subsequent generations. Furthermore, youth unemployment is longitudinally related to mental health problems, independent of the overall national unemployment rate. These findings are of importance, as alcohol remains a leading cause of morbidity and mortality and youth unemployment rates are currently at a stable high level both nationally and globally

Plasma levels of buprenorphine following oral and intravenous administration in rabbits

I takt med att kaninens (Oryctolagus cuniculus) popularitet ökar och kravet på alltmer avancerad veterinärvård växer krävs kunskap om hur man smärtlindrar kanin på bästa sätt. Kaninen är ett utpräglat bytesdjur som döljer smärta väl, särskilt i stressade situationer som vid klinikvistelse. Buprenorfin är en vanligt använd opioid för smärtlindring av kaniner. På klinik administreras läkemedlet genom injektion, men för fortsatt smärtlindring i hemmet behövs en mer djurägaranpassad administeringsväg och peroral (PO) administrering skulle kunna vara ett alternativ. Dock är biotillgängligheten av buprenorfin efter PO adminsitrering till kanin inte känd. Syftet med denna studie var att undersöka biotillgängligheten av buprenorfin efter PO tillförsel samt se vilka plasmakoncentrationer av buprenorfin som uppnås efter intravenös (IV) och PO administrering till kanin. I studien mättes plasmahalter av buprenorfin efter IV (0,05 mg/kg) och PO (0,5 mg/kg) tillförsel till nio intakta honkaniner av rasen New Zealand White med en medelvikt på 2,96 kg (± 0,35). PO administreringen utfördes genom att läkemedlet deponerades med en spruta långt bak i munnen. Sex kaniner administrerades buprenorfin antingen IV (n=3) eller PO (n=3) och tre kaniner (n=3) administrerades både IV och PO med två veckors mellanrum. Blodprover togs via en separat kateter i örats centralartär vid 2 (endast IV), 5, 15, 30, 60, 90, 180, 360 och 480 minuter efter läkemedelsadministrering. Plasma analyserades för buprenorfinkoncentrationer genom ultrahög-prestanda vätskekromatografi-tandemmasspektrometri på Statens veterinärmedicinska laboratorium (SVA, Uppsala, Sverige). Medelvärden för buprenorfinkoncentrationer beräknades vid samtliga mättidpunkter samt för halveringstid (T1/2), uppmätt maximal koncentration (Cmax), tid vid uppmätt Cmax (Tmax) och arean under plasmakoncentrationskurvan (AUC0-t) vid IV och PO administrering. Buprenorfinkoncentrationerna efter PO administrering var signifikant (p <0,05) lägre än efter IV tillförsel vid alla provtagningstidpunkter vid tvåvägs variansanalys (mixed two-way- repeated-measures ANOVA). Efter PO administrering var medelvärdet för Cmax 2,3 (± 0,8) ng/ml och Tmax 16 (± 7,8) minuter. Statistisk analys för T1/2 och AUC utfördes genom oparade t-tester med en signifikansgräns av p <0,05. Halveringstiden skilde sig inte signifikant mellan IV och PO tillförsel av buprenorfin. Arean under plasmakoncentrationskurvan var signifikant större efter IV tillförsel trots att en tio gånger högre dos buprenorfin gavs PO. Biotillgängligheten för PO administrering uppgick till 2,7 % . Jämfört med IV tillförsel, gav PO tillförsel av buprenorfin upphov till signifikant lägre koncentrationer i plasma, trots en 10 gånger högre administreringsdos. Det är tveksamt om den uppnådda plasmakoncentrationen efter PO administrering av 0,5 mg/kg är tillräcklig för analgesi. Vidare var volymen stor vilket försvårade administreringen eftersom flera av kaninerna var ovilliga att svälja läkemedlet. Detta bidrog troligen till att även ett oral transmukosalt (OTM) upptag av buprenorfin skedde. Slutsatsen är att PO administrering av buprenorfin till kanin inte kan rekommenderas.With the growing popularity of the rabbit (Oryctolagus cuniculus) as a household pet, the requirement for increasingly advanced veterinary care grows and knowledge of how to efficiently relieve pain in the the rabbit is lacking. The rabbit, typical of a prey animal, conceals pain well, especially in stressful situations such as visits to a veterinary clinic. Buprenorphine is a commonly used opioid for pain relief of rabbits. In the clinic, the drug is administered by injection but for continued pain relief in the home an easier way of administration is preferable, wherefore oral (PO) administration could be an alternative. However, the bioavailability of buprenorphine after PO administration to rabbits is not known. The purpose of this study was to investigate the bioavailability of buprenorphine after oral administration in rabbits and the plasma levels of buprenorphine following PO and intravenous (IV) administration. Blood plasma concentrations of buprenorphine were measured after IV (0.05 mg/kg) and PO (0.5 mg/kg) administration to nine New Zealand White intact female rabbits with a mean weight of 2.96 kg (± 0.35). PO administration was performed by depositing the drug with a syringe far back in the mouth. Six rabbits were administred buprenorphine either by the intravenous (n=3) or oral (n=3) route and three were administred IV and PO with a two week wash out period. Blood samples were taken via a catheter in the central artery of the ear at 2 (IV only), 5, 15, 30, 60, 90, 180, 360 and 480 minutes after administration. Plasma was analyzed for buprenorphine concentrations by ultra high performance liquid chromatography tandem mass spectrometry at the Swedish National Veterinary Institute (Statens veterinärmedicinska anstalt, SVA, Uppsala, Sverige). Mean values were calculated for buprenorphine concentrations at all time points as well as halflife (T1/2), maximum plasma concentration (Cmax), time at Cmax (Tmax) and for the area under the plasma concentration curve (AUC0-t) after IV and PO administration. The buprenorphine concentrations after oral administration was significantly (p < 0,05) lower than after intravenous administration at all sampled times points using a mixed two-way-repeated-measure ANOVA. After oral administration the mean Cmax was 2.3 (± 0.8) ng/ml and Tmax 16 (± 7.8) minutes. Statistical analysis for T1/2 and AUC was performed by an unpaired t-test. The level of significans was set at p <0.05. The half-life did not differ significantly between IV and PO administration. The area below the plasma concentration curve was significantly larger after IV administration despite the higher dose of buprenorphine used for PO administration. Bioavailability of buprenorphine was 2.7% after PO administration. Oral administration of buprenorphine resulted in significantly lower plasma concentrations than IV administration, despite a 10-fold higher dose. It is doubtful whether the achieved plasma concentration after PO administration of 0.5 mg/kg is sufficient for analgesia in rabbits. Furthermore, the volume required for PO administration is high which complicates treatment. Several rabbits in this study were unwilling to swallow the drug completely, probably resulting in a simultaneously oral transmucosal (OTM) uptake of buprenorphine. The results of this study suggest that PO administration of buprenorphine to rabbits can not be recommended

The development of calcium oxalate uroliths : a review of potential predisposing factors

Urinsten, urolithiasis, är en relativt vanlig åkomma i hundens urinvägar. Stenarna är uppbyggda av olika mineraler och salter av vilka kalciumoxalat och struvit (magnesiumammoniumfosfat) är de vanligaste, ensamma eller i kombination med andra ämnen. Stenarna återfinns framförallt i de nedre urinvägarna, det vill säga i urinblåsa och urinrör. De kan ställa till stora problem genom obstruktion och svår smärta. De upptäcks vanligtvis genom röntgen och måste ofta avlägsnas kirurgiskt men risken för att nya stenar utvecklas är stor. Stenar uppbyggda av kalciumoxalat är ett växande problem i stora delar av världen. I dagsläget är orsaken till uppkomsten av kalciumoxalatstenar till stor del oklar och flera faktorer tros vara inblandade i utvecklingen. Under de senaste decennierna har man sett en ökning av andelen diagnosticerade kalciumoxalatstenar hos hund. En samtidig ökning har setts hos människa och katt. Det finns både likheter och skillnader mellan de olika arterna, till exempel återfinns de flesta av urinstenar hos människa i njuren medan detta är en mycket ovanlig lokalisering hos hund. Flera olika faktorer som kan påverka urinens sammansättning har studerats hos människa för att komma fram till varför en så kraftig ökning skett men forskning gjord på hund är mindre omfattande. Övermättnad av urinen med de metaboliter som bygger upp stenen anses vara en viktig faktor och samtidigt verkar andra faktorer som exempelvis urin-pH, urinvolym, oxalatmetaboliserande tarmbakterier och hull ha en avgörande roll i stenutvecklingen. Även om hundar av alla åldrar, raser och kön kan drabbas av kalciumoxalatstenar i urinvägarna så förefaller hanhundar, framförallt kastrerade, av småväxta raser i övre medelåldern ha en förhöjd risk jämfört med andra grupper. Nutritionsfaktorer tros genom sin påverkan på urinsammansättningen kunna påverka uppkomsten av urinsten, antingen genom promotorisk eller genom inhibitorisk verkan. Även könshormoner, så som östrogen och testosteron, har visat sig ha en koppling till utveckling av kalciumoxalatstenar hos människa och råtta men inga studier om deras påverkan på hund verkar finnas publicerade idag. Sammantaget är utvecklingen av kalciumoxalatstenar komplex och många olika faktorer medverkar. Ett fåtal potentiella faktorer som; urinsammansättning, övermättnad av olika metaboliter i urinen, urinvolym, närvaro eller avsaknad av promotorer och inhibitorer, hundens kondition och olika dieter antas kunna ha en koppling till stenutvecklingen. Bristen på studier utförda på hund gör det svårt att dra några definitiva slutsatser om vad som predisponerar för kalciumoxalatstenar och för att utvärdera olika faktorers association och inverkan på stenutvecklingen krävs fler studier utförda på hund.Uroliths, urinary stones, are a common disease in the urinary tract of dogs. Stones may contain different types of minerals and salts; the greatest proportion of stones are built up by either calcium oxalate or struvite (magnesium ammonia phosphate), alone or combined with other minerals. Stones are most often located in the lower urinary tract, ie in the bladder and urethra where they can cause problems by obstruction and pain. Calcium oxalate uroliths are usually seen on x-ray and surgery is often needed for removal but the rate of recurrence is high. Calcium oxalate containing uroliths are an increasing problem in most parts of the world. The cause of calcium oxalate uroliths is still unknown and seems to be multifactorial. In recent decades there has been a rising trend in calcium oxalate uroliths diagnosed in dogs. A similar trend is seen in humans and cats. There are similarities but also differences between species, for example, most urinary stones in humans are found in the kidneys while this location is extremely rare in dogs. In humans, several different factors affecting urine composition have been studied to determine why such a large increase has occurred, but research in dogs has been less comprehensive. Oversaturated urine is considered to be a risk factor but other factors of importance are also associated with the development of calcium oxalate uroliths, eg. urine-pH, urine volume, oxalate metabolizing intestinal bacteria and body condition. Although dogs of different age, breeds and sex can be affected, males, in particular neutered, small breed dogs in their late middle age seem to be at higher risk compared to other groups. Nutritional factors are thought to influence stone formation, in either a promoting or inhibitory way, through their effects on urine composition. In addition, sex hormones, such as estrogen and testosterone, also appear to play an important role in the development of calcium oxalate uroliths in human and rat, however, there are no published studies on their role in stone formation in dogs. Taken together, current evidence would suggest stone formation is a complex process and many different factors are likely to be involved in its progression. A few potential factors such as; urine composition, urine supersaturation of different metabolites, urine volume, presence or absence of promotors and inhibitors, nutrition state and different diets have been implied in dogs. The lack of studies in dogs makes it challenging to evaluate the different predisposing factors associated with the formation of canine calcium oxalate uroliths and more research focusing on risk factors in dogs is required

Feasibility Study of Ubiquitous Interaction Concepts

AbstractThere are all sorts of consumer electronics in a home environment. Using “apps” to interact with each device is neither feasible nor practical in an ubicomp future. Prototyping and evaluating interaction concepts for this future is a challenge. This paper proposes four concepts for device discovery and device interaction implemented in a virtual environment. The interaction concepts were compared in a controlled experiment for evaluation and comparison.Some statistically significant differences and subjective preferences could be observed in the quantitative and qualitative data respectively.Overall, the results indicate that the proposed interaction concepts were found natural and easy to use