Liquid methane is becoming an increasingly attractive rocket propellant due to its high performance characteristics and potential to support in-situ resource utilisation. Methane, however, when heated, can thermally decompose in a process known as pyrolysis. In regeneratively cooled rocket engines, the solid carbon products from the pyrolysis reactions are deposited on the walls of the cooling channels. This increases the thermal resistance of the channel walls, resulting in higher wall temperatures. In turn, this can facilitate cracking and crack propagation, presenting a potential problem in rockets, especially for future reusable designs. It will therefore be necessary to inspect the state of the cooling channels between flights. The carbon layer also changes the catalytic properties of the surface, affecting the onset temperature of methane pyrolysis, and thus impacting the pyrolysis behaviour during subsequent flights. It is possible to clean the channel using a mixture of gaseous oxygen and ozone, however, preliminary testing has indicated that not all the carbon is removed within a reasonable time frame. An experimental facility exists which can control the thermal and flow conditions in straight test channels to replicate the conditions seen in methane rocket nozzle cooling channels. The purpose of this project is to develop a system to quantitatively assess the amount of carbon deposition in these test channels after methane pyrolysis has occurred within them, and following ozone cleaning. The developed system is an optical method which uses a borescope to capture images within the coked channel. These images are then run through bespoke image processing software to determine the proportion of the inner channel wall that is coked. The software has been developed and a provisional mechanical setup has been designed. Initial validation tests have been conducted to assess the accuracy of the software used in conjunction with the borescope and camera. The results indicate that the system is capable of quantifying coke in a metal channel with an error of 1.489%±0.232% or less. / Flytande metan är på väg att bli ett mera attraktivt raketbränsle på grund av sina högprestanda-egenskaper samt potential för att stödja resursanvändning, in situ. Hursomhelst så kan metan, då uppvärmt, termiskt brytas ned i en process kallad pyrolys. I regenerativt kylda raketmotorer så utfälls de solida kolprodukterna från pyrolysen på väggarna av kylkanalerna. Detta höjer den termiska resistansen hos kanalens väggar vilket resulterar i högre väggtemperaturer. Detta kan, i sin tur, leda till spricktillväxt som väcker ett potentiellt problem med raketer, speciellt för framtida återanvändningsbara designer.Det kommer därför vara nödvändigt att inspektera skicket av kylkanalerna mellan flygningar. Kollagret förändrar också de katalyserande egenskaperna av ytan, vilket har en inverkan på begynnelsetemperaturen av metanpyrolys, som påverkar hur pyrolysen beter sig för följande flygningar.Däremot är möjligt att rena kanalerna genom att använda en blandning av syre i gasform, och ozon. Preliminära tester indikerar på att inte allt kol är borttaget inom en rimlig tidsram. En experimentell anläggning finns, som kan kontrollera tillstånd för värme och flöde i raka testkanaler för att replikera tillstånden som setts i kylkanaler i dysor för metanraketer. Syftet med detta projekt är att utveckla ett system för att kvatitativt bedöma mängden koldeposition i dessa testkanaler efter att pyrolys av metan har skett i dem, följt av ozon-rening. Det utvecklade systemet är en optisk metod som använder ett boroskop för att fånga bilder inuti den kanalen med koks. Dessa bilder körs genom ett skräddarsytt bildprocesseringsprogram för att bestämma proportionerna av den inre kanalväggen med koks. Mjukvaran har utvecklats och en provisorisk mekanisk anordning har utformats. Initiella valideringstester har genomförts för att bedöma noggrannheten av mjukvaran som använts i samband med boroskopet och kameran. Resultaten indikerar på att systemet är kapabelt att kvatifiera koks in en metallkanal med ett fel på 1,489%±0,232% eller mindre.

The proton exchange membrane fuel cell generates electricity from hydrogen and oxygen (from air) through electrocatalytic reactions in an electrochemical cell. The Pt/C catalyst, commonly used in PEM fuel cells, is very sensitive to impurities that can interact with the active catalyst sites and limit fuel cell performance. Unfortunately, most hydrogen is currently produced from fossil sources, and inevitably contains impurities. The subject of this thesis is the effect of hydrogen impurities on the operation of a PEM fuel cell using a Pt/C anode. The impurities studied are carbon monoxide (CO), carbon dioxide (CO2), and selected hydrocarbons. Particular focus is given to the interaction between the impurities studied and the anode catalyst. The main method used in the study involved performing cyclic voltammetry and mass spectrometry, simultaneously. Other electrochemical techniques are also employed. The results show that all the impurities studied adsorb to some extent on the Pt/C catalyst surface, and require potentials comparable to that of CO oxidation, i.e., about 0.6V, or higher to be removed by oxidation to CO2. For complete oxidation of propene, and toluene, potentials of above 0.8, and 1.0V, respectively, are required. The unsaturated hydrocarbons can be desorbed to some extent by reduction, but oxidation is required for complete removal. Adsorption of ethene, propene, and CO2 is dependent on the presence of adsorbed or gaseous hydrogen. Hydrogen inhibits ethene and propene adsorption, but facilitates CO2 adsorption. Adsorption of methane and propane is very limited and high concentrations of methane cause dilution effects only. The adlayer formed on the Pt/C anode catalyst in the presence of CO2, or moderate amounts of hydrocarbons, is found to be insffuciently complete to notably interfere with the hydrogen oxidation reaction. Higher concentrations of toluene do, however, limit the reaction. / Polymerelektrolytbränslecellen genererar elektricitet fran vätgas och syrgas (fran luft) genom elektrokatalytiska reaktioner i en elektrokemisk cell. Den platina-baserade katalysator som oftast används i dessa bränsleceller är känslig mot föroreningar, då dessa kan interagera med katalysatorns aktiva yta, och därmed begränsna bränslecellens prestanda. Tyvärr produceras dagens vätgas huvudsakligen fran fossila källor och innehåller därför oundvikligen föroreningar. Denna avhandling behandlar hur olika vätgasföroreningar påverkar katalysatorns aktivitet och bränslecellens drift. De föroreningar som studeras är kolmonoxid (CO) och koldioxid (CO2), samt ett antal mindre kolväten. Störst fokus ligger på hur dessa föroreningar interagerar med anodens Pt/C katalysator. Den metod som huvudsakligen används är cyklisk voltammetri kombinerat med masspektrometri, men flera elektrokemiska metoder har använts. Resultaten visar att alla undersökta föroreningar adsorberar på Pt/C katalysatorns yta i större eller mindre utstreckning. For att avlägsna det adsoberade skiktet genom oxidation till CO2 krävs potentialer jämförbara med CO oxidation, dvs ca 0,6V, eller högre. Fullständig oxidation av propen eller toluen kräver potentialer högre än 0,8V respektive 1,0V. De omättade kolvätena kan delvis avlägsnas genom reduktion, men fullständig avlägsning kräver oxidation. Närvaron av väte, i gasform eller adsorberat pa katalysatorn, hämmar adsorptionen av eten och propen, men främjar CO2 adsorption. Metan och propan adsorberar i mycket begränsad utstreckning på Pt/C katalysatorns yta. De prestandaförluster som uppstår av höga koncentrationer av metan förklaras av utspädning av vätgasen. Det adsorberade skiktet som bildas när Pt/C katalysatorn exponeras för CO2 eller måttliga koncentrationer av studerade kolväten, är inte tillräckligt heltäckande for att märkbart påverka vätgasreduktionen. Däremot kan höga koncentrationer av toluen begränsa reaktionen. / <p>QC 20161010</p>

This thesis consists of one chapter accepted for publication in a book and four papers published in international journals with impact factors. All of the contributions deal with the role of wood ants in energy and nutrient fluxes in forest ecosystems. Wood ant nests are known as hot spots of carbon dioxide (CO2) production and are also thought to affect methane (CH4) flux. Stable high temperatures are maintained in ant nests even in cold environments. This study is focused on quantification of CO2 and CH4 flux in wood ant nests, contribution of ants and microbes to CO2 production, properties of nest material that affect CO2 production and the role of ants and microbes in the maintenance of nest temperature. The research was conducted in temperate and boreal forests inhabited by wood ants (Formica s. str.). Gas fluxes were measured either by an infrared gas analyser or a static chamber technique. Ants and nest materials were also incubated in a laboratory. Material properties potentially influencing CO2 flux, such as moisture, nutrient content or temperature were determined. According to the results, CH4 oxidation was lower in wood ant nests than in the surrounding forest soil suggesting that some characteristics of ant nests hinder CH4 oxidation or promote CH4 production. Wood ant nests clearly are hot...

<p>Biogas är benämningen för metangas (CH₄) som är producerad via anaerob (syrefri) rötning av biologiskt material. I Linköping finns en av Sveriges största biogasanläggningar. Anläggningen drivs av Svensk Biogas AB som ägs av Tekniska Verken i Linköping AB (publ.). I anläggningen rötas stora mängder proteinrikt substrat vilket leder till höga halter av ammoniak (NH₃) och ammonium (NH₄⁺) i rötkammaren. Ammoniak (NH₃) är toxiskt för de metanbildare som i en välmående process står för den största delen av metangasproduktionen. Höga halter av ammoniak (NH₃) och ammonium (NH₄⁺) kan inhibera dessa metanbildare vilket leder till minskad gasproduktion.</p><p>Detta examensarbete syftar främst till att genom ett kontinuerligt rötkammarexperiment utreda om zeoliter är ett lämpligt hjälpmedel för att reducera ammonium (NH₄⁺) i en anaerob process. Vid sänkta halter ammonium (NH₄⁺) är hypotesen att de mikroorganismer som är aktiva i den mest effektiva metanbildningsvägen återetableras. Arbetet syftar även till att experimentellt utreda vilka effekter zeoliter i sin helhet har på den anaeroba processen. Zeoliters effekt vid låga zeolitkoncentrationer utreds i en serie utrötningsexperiment i batch. Dessutom har en materialstudie kring zeoliternas kapacitet i olika miljöer genomförts.</p><p>Materialstudien visade att den valda zeoliten som studerades, clinoptilolite, hade en maximal katjonbytarkapacitet på ≈ 19 mg NH₄⁺/g zeolit. Vidare konstaterades att zeoliter med mindre diameter än 1 mm har avsevärt bättre kapacitet än zeoliter med större diameter. I det kontinuerliga rötkammarexperimentet konstaterades att clinoptilolite kan användas i en rötkammare för att reducera ammoniumhalten (NH₄⁺). Detta utan att några allvarliga processtörningar uppstår. Cirka 175 g zeolit/l krävdes för att reducera ammoniumhalten (NH₄⁺) från 5300 mg NH₄⁺/l till 3200 mg NH₄⁺/l. Det är inte realistisktatt använda så stora mängder zeoliter i en fullskalig anläggning. Mikrobiologiskt sett observerades ingen förändring av de metanbildarna som dominerar den effektivaste metanbildningsvägen.</p><p>Resultaten från utrötningsförsöket i batch visade att zeolittillsatser av 5 g/l respektive 10 g/l hade en klart positiv effekt på metanbildningen jämfört utan zeolittillsats. I de batcher med 1-10 g zeolit/l startade metangasproduktionen ≈ 14 dagar tidigare än batcherna med 0 g zeolit/l. 16 dagar efter att experimentet startade hade batcherna med 5-10 g zeolit/l producerat ≈ 500 ml metangas (CH₄) jämfört med serien utan zeoliter som vid samma tidpunkt producerat ≈ 75 ml metangas (CH₄). Utrötningsgraden ökade i samtliga serier med zeolittillsats jämfört med serien utan zeoliter. Tillsatsen av 5 g zeolit/l ökade den specifika metangasproduktionen med ≈ 19 % jämfört med utan zeolittillsatser. Slutsatsen är att clinoptilolite i små koncentrationer, mellan 5-10 g/l, påverkar så väl kinetiken som utrötningsgraden för den anaeroba processen på ett positivt sett. Den optimala koncentrationen av clinoptilolite i en mesofil anaerob process bör ligga mellan 5-10 g zeolit/l.</p> / <p>Methane (CH₄) is formed by anaerobic (oxygen-free) digestion of biological materials. One of Sweden's largest biogas plants is placed in Linköping. The plant is operated by Svensk Biogas AB, which is owned by Tekniska Verken i Linköping AB (publ.). In their biogas plant a large amount of protein rich material is handled. High amounts of protein leads to high levels of ammonia (NH₃) and ammonium (NH₄⁺) in the digestion chamber. High levels of ammonia (NH₃) are toxic to the most dominant methane forming microorganism. High concentrations of ammonia (NH₃) and ammonium (NH₄⁺) can inhibit these methane forming microorganisms which may lead to a reduction in gas production.</p><p>This aim with this master thesis was to reduce high ammonium levels by adding zeolites to a lab scale continuous digestion chamber. The hypothesis is that at reduced levels of ammonium (NH₄⁺) the most effective methane forming microorganism will reestablish. This thesis also aims to experimentally investigate all types of effects that zeolites may have in an anaerobic digestion process. Which effect zeolites at low concentration have in a digestion chamber will be investigated by using lab scale batch digestion chambers. In addition, a material study on the capacity of the zeolites in different environments will be investigated.</p><p>The material study showed that the selected zeolite, clinoptilolite, had a cat ion exchange capacity around 19 mg NH₄⁺/g zeolite. It was also found that the zeolites with a diameter less than 1 mm had significantly better capacity than zeolites with larger diameter. In the continuous digestion experiment it was found that clinoptilolite can be used in a digestion chamber to reduce high levels of ammonium (NH₄⁺). This without any serious disorder on the process. Around 175 g zeolite/l was needed to reduce ammonium levels (NH₄⁺) from 5300 mg NH₄⁺/l to 3200 mg NH₄⁺/l. However, it is not realistic to use such large amounts of zeolites in a full-scale digestion chamber. No changes in the culture of methane forming microorganisms were found.</p><p>The results of the batch experiment showed that concentrations of 5 g zeolite/l and 10 g zeolite/l had a positive effect on the methanogenesis compared to batches without additives. In the batches with 1-10 g zeolite/l the forming of methane began about 14 days earlier than in the batches without any zeolites. After 16 days, batches with 5-10 g zeolite/l had produced about 500 ml of methane (CH₄), compared with series without additives, which at the same time had produced about 75 ml of methane (CH₄). The methane yield increased in all series which included zeolites compared to the batches without zeolites. Addition of 5 g zeolite/l increased the specific methane production by approximately 19 % compared to no additives. The conclusion is that clinoptilolite in small concentrations; 5-10 g/l have a positive effect on as well the kinetics as on the methane yield for the anaerobic process. The best concentration of zeolites in a mesophile anaerobic digestion chamber appears to be between 5-10 g zeolite/l.</p>

Biogas är benämningen för metangas (CH4) som är producerad via anaerob (syrefri) rötning av biologiskt material. I Linköping finns en av Sveriges största biogasanläggningar. Anläggningen drivs av Svensk Biogas AB som ägs av Tekniska Verken i Linköping AB (publ.). I anläggningen rötas stora mängder proteinrikt substrat vilket leder till höga halter av ammoniak (NH3) och ammonium (NH4+) i rötkammaren. Ammoniak (NH3) är toxiskt för de metanbildare som i en välmående process står för den största delen av metangasproduktionen. Höga halter av ammoniak (NH3) och ammonium (NH4+) kan inhibera dessa metanbildare vilket leder till minskad gasproduktion. Detta examensarbete syftar främst till att genom ett kontinuerligt rötkammarexperiment utreda om zeoliter är ett lämpligt hjälpmedel för att reducera ammonium (NH4+) i en anaerob process. Vid sänkta halter ammonium (NH4+) är hypotesen att de mikroorganismer som är aktiva i den mest effektiva metanbildningsvägen återetableras. Arbetet syftar även till att experimentellt utreda vilka effekter zeoliter i sin helhet har på den anaeroba processen. Zeoliters effekt vid låga zeolitkoncentrationer utreds i en serie utrötningsexperiment i batch. Dessutom har en materialstudie kring zeoliternas kapacitet i olika miljöer genomförts. Materialstudien visade att den valda zeoliten som studerades, clinoptilolite, hade en maximal katjonbytarkapacitet på ≈ 19 mg NH4+/g zeolit. Vidare konstaterades att zeoliter med mindre diameter än 1 mm har avsevärt bättre kapacitet än zeoliter med större diameter. I det kontinuerliga rötkammarexperimentet konstaterades att clinoptilolite kan användas i en rötkammare för att reducera ammoniumhalten (NH4+). Detta utan att några allvarliga processtörningar uppstår. Cirka 175 g zeolit/l krävdes för att reducera ammoniumhalten (NH4+) från 5300 mg NH4+/l till 3200 mg NH4+/l. Det är inte realistisktatt använda så stora mängder zeoliter i en fullskalig anläggning. Mikrobiologiskt sett observerades ingen förändring av de metanbildarna som dominerar den effektivaste metanbildningsvägen. Resultaten från utrötningsförsöket i batch visade att zeolittillsatser av 5 g/l respektive 10 g/l hade en klart positiv effekt på metanbildningen jämfört utan zeolittillsats. I de batcher med 1-10 g zeolit/l startade metangasproduktionen ≈ 14 dagar tidigare än batcherna med 0 g zeolit/l. 16 dagar efter att experimentet startade hade batcherna med 5-10 g zeolit/l producerat ≈ 500 ml metangas (CH4) jämfört med serien utan zeoliter som vid samma tidpunkt producerat ≈ 75 ml metangas (CH4). Utrötningsgraden ökade i samtliga serier med zeolittillsats jämfört med serien utan zeoliter. Tillsatsen av 5 g zeolit/l ökade den specifika metangasproduktionen med ≈ 19 % jämfört med utan zeolittillsatser. Slutsatsen är att clinoptilolite i små koncentrationer, mellan 5-10 g/l, påverkar så väl kinetiken som utrötningsgraden för den anaeroba processen på ett positivt sett. Den optimala koncentrationen av clinoptilolite i en mesofil anaerob process bör ligga mellan 5-10 g zeolit/l. / Methane (CH4) is formed by anaerobic (oxygen-free) digestion of biological materials. One of Sweden's largest biogas plants is placed in Linköping. The plant is operated by Svensk Biogas AB, which is owned by Tekniska Verken i Linköping AB (publ.). In their biogas plant a large amount of protein rich material is handled. High amounts of protein leads to high levels of ammonia (NH3) and ammonium (NH4+) in the digestion chamber. High levels of ammonia (NH3) are toxic to the most dominant methane forming microorganism. High concentrations of ammonia (NH3) and ammonium (NH4+) can inhibit these methane forming microorganisms which may lead to a reduction in gas production. This aim with this master thesis was to reduce high ammonium levels by adding zeolites to a lab scale continuous digestion chamber. The hypothesis is that at reduced levels of ammonium (NH4+) the most effective methane forming microorganism will reestablish. This thesis also aims to experimentally investigate all types of effects that zeolites may have in an anaerobic digestion process. Which effect zeolites at low concentration have in a digestion chamber will be investigated by using lab scale batch digestion chambers. In addition, a material study on the capacity of the zeolites in different environments will be investigated. The material study showed that the selected zeolite, clinoptilolite, had a cat ion exchange capacity around 19 mg NH4+/g zeolite. It was also found that the zeolites with a diameter less than 1 mm had significantly better capacity than zeolites with larger diameter. In the continuous digestion experiment it was found that clinoptilolite can be used in a digestion chamber to reduce high levels of ammonium (NH4+). This without any serious disorder on the process. Around 175 g zeolite/l was needed to reduce ammonium levels (NH4+) from 5300 mg NH4+/l to 3200 mg NH4+/l. However, it is not realistic to use such large amounts of zeolites in a full-scale digestion chamber. No changes in the culture of methane forming microorganisms were found. The results of the batch experiment showed that concentrations of 5 g zeolite/l and 10 g zeolite/l had a positive effect on the methanogenesis compared to batches without additives. In the batches with 1-10 g zeolite/l the forming of methane began about 14 days earlier than in the batches without any zeolites. After 16 days, batches with 5-10 g zeolite/l had produced about 500 ml of methane (CH4), compared with series without additives, which at the same time had produced about 75 ml of methane (CH4). The methane yield increased in all series which included zeolites compared to the batches without zeolites. Addition of 5 g zeolite/l increased the specific methane production by approximately 19 % compared to no additives. The conclusion is that clinoptilolite in small concentrations; 5-10 g/l have a positive effect on as well the kinetics as on the methane yield for the anaerobic process. The best concentration of zeolites in a mesophile anaerobic digestion chamber appears to be between 5-10 g zeolite/l.

Made available in DSpace on 2014-12-17T15:16:17Z (GMT). No. of bitstreams: 1 IvaniziaSS_DISSERT.pdf: 831811 bytes, checksum: 8d5c9ce3de798ff5fead323295073f95 (MD5) Previous issue date: 2012-12-17 / In asthmatic, the lung hyperinflation leaves the inspiratory muscle at a suboptimal position in length-tension relationship, reducing the capacity of to generate tension. The increase in transversal section area of the inspiratory muscles could reverse or delay the deterioration of inspiratory muscle function. Objective: To evaluate the evidence for the efficacy of inspiratory muscle training (IMT) with an external resistive device in patients with asthma. Methods: A systematic review with meta-analysis was carried out. The sources researched were the Cochrane Airways Group Specialised Register of trials, Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 11 of 12, 2012), MEDLINE, EMBASE, PsycINFO, CINAHL, AMED, ClinicalTrials.gov and reference lists of articles. All databases were searched from their inception up to November 2012 and there was no restriction on the language of publication. Randomised controlled trials that involved the use of an external inspiratory muscle training device versus a control (sham or no inspiratory training device) were considered for inclusion. Two reviewers independently selected articles for inclusion, evaluated risk of bias in studies and extracted data. Results: A total of five studies involving 113 asthmatic patients were included. Three clinical trials were produced by the same group. The included studies showed a significant increase in maximal inspiratory pressure (MD 13.34 cmH2O, 95% CI 4.70 to 21.98), although the confidence intervals were wide. There was no statistically significant difference between the IMT group and the control group for maximal expiratory pressure, peak expiratory flow rate, forced expiratory volume in one second, forced vital capacity, sensation of dyspnea and use of beta2-agonist. There were no studies describing exacerbation events that required a course of oral and inhaled corticosteroids or emergency department visits, inspiratory muscle endurance, hospital admissions and days of work or school. Conclusions: There is no conclusive evidence in this review to support or refute inspiratory muscle training for asthma, once the evidence was limited by the small number of studies included, number of participants in them together with the risk of bias. More well conducted randomized controlled trials are needed, such trials should investigate respiratory muscle strength, exacerbation rate, lung function, symptoms, hospital admissions, use of medications and days off work or school. IMT should also be assessed in the context of more severe asthma / No paciente asm?tico, a hiperinsufla??o pulmonar coloca os m?sculos inspirat?rios em uma posi??o desfavor?vel na rela??o comprimento-tens?o, reduzindo a capacidade de gerar tens?o. O aumento na ?rea de sec??o transversa dos m?sculos inspirat?rios poderia reverter ou atrasar a deteriora??o da fun??o muscular inspirat?ria. Objetivo: Avaliar a evid?ncia da efic?cia do treinamento muscular inspirat?rio (TMI) com um dispositivo externo em pacientes com asma. M?todos: O tipo de estudo utilizado foi uma revis?o sistem?tica com metan?lise. As fontes pesquisadas foram o Cochrane Airways Group Specialised Register of trials, Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 11 of 12, 2012), MEDLINE, EMBASE, PsycINFO, CINAHL, AMED, ClinicalTrials.gov e lista de refer?ncias dos artigos. Todas as bases de dados foram pesquisadas desde seu in?cio at? novembro de 2012 e n?o houve restri??o de idioma. Foram considerados para inclus?o ensaios cl?nicos controlados e randomizados envolvendo o uso de um aparelho de treinamento muscular inspirat?rio externo versus um controle (placebo ou sem aparelho). Dois revisores independentemente selecionaram os artigos para inclus?o, avaliaram o risco de vi?s e extra?ram os dados dos estudos inclu?dos. Resultados: Um total de cinco estudos envolvendo 113 pacientes asm?ticos foram inclu?dos na revis?o, sendo 3 destes ensaios desenvolvidos pelo mesmo grupo. Os estudos inclu?dos mostraram que o TMI aumenta significativamente a press?o inspirat?ria m?xima (DM 13.34 cmH2O, 95% IC 4.70 ? 21.98), contudo existiu um largo intervalo de confian?a. N?o houve diferen?a significativa entre o grupo TMI e o grupo controle para press?o expirat?ria m?xima, taxa de pico de fluxo expirat?rio, volume expirat?rio for?ado no primeiro segundo, capacidade vital for?ada, sensa??o de dispneia e uso de beta2-agonista. Nenhum estudo investigou os seguintes desfechos: exacerba??es que requereram o uso de corticosteroides inalado ou oral ou visita ao servi?o de emerg?ncia m?dica, endurance dos m?sculos inspirat?rios, admiss?o no hospital e dias de falta ao trabalho ou escola. Conclus?es: N?o existe evid?ncia conclusiva para apoiar ou refutar o uso do TMI para a asma, uma vez que a evid?ncia foi limitada pelo pequeno n?mero de ensaios inclu?dos, reduzido n?mero de participantes e risco de vi?s. Mais estudos randomizados e controlados bem xiv conduzidos s?o necess?rios, tais ensaios devem investigar a for?a muscular respirat?ria, exacerba??es, fun??o pulmonar, sintomas, admiss?o no hospital, uso de medicamentos e dias de falta ao trabalho ou escola. O TMI deve tamb?m ser avaliado no contexto de asma mais grave

Biogas is an expanding sector within the broad field of agriculture and animal production. Small-scale biogas offers local combined power and heating production and the substrate is transformed into high-quality biological fertilizer. This bachelor thesis focuses on a pig farm in south-western Sweden, where biogas is produced from pig manure, evaluates and suggests ways of optimizing the process and investigates whether investing in an upgrading plant would be a feasible and more cost-efficient option. The results show that the biogas plant is working well, although the production differs from the original plans. This shows in turn that planning and examining the basic conditions before making the investment is of great importance, as well as monitoring and keeping detailed statistics of the running process. Logistical factors make optimizing the process through additional substrates difficult. The thesis shows that investing in a Biosling upgrading plant would be a profitable option, supposing that the upgraded gas is sold via the natural gas infrastructure. Furthermore, many farmers are interested in producing their own fuel for tractors and other machines, which offers more future alternatives for the upgraded biogas. However, biogas producers in Sweden today are not offered any particular subsidies, which makes it especially hard for small-scale producers.

This thesis deals with technologies for gas liquefaction and storage. The first section summarizes the development of liquefaction technology using expanders and throttling valves, followed by current technology. This is especially a rotary expanders. The storage technology is the above-ground storage of cryogenic tanks. The thesis includes proposals turbine wheels for liquefaction lines and included two proposals liquefaction cycles.

Käppala wastewater treatment plant (WWTP) has, during a few years, observed an increase in organic loading rate (OLR) in the mesophilic anaerobic digester R100, due to an increased load to the WWTP. The digestion of primary sludge at Käppala WWTP is today high loaded, with a high organic loading rate (OLR) and low hydraulic retention time (HRT). This study aims to evaluate the effect of the maximum OLR and the minimum HRT for the anaerobic digestion of sewage sludge and to investigate further actions that can be taken into consideration in case of process problems in the digestion. The study consists of (a) a practical laboratory experiment of 6 pilot-scale reactors to investigate how the process stability is affected when the OLR increases and the HRT decreases. (b) A mass balance calculation based on the energy potential in the feeding sludge and the digested sludge. (c) A study of the filterability of the digested sludge. (d) The construction of a forecasting model in Excel, to predict when digester R100 will reach its maximum OLR and minimum HRT. The result of the study shows that the maximum OLR for Käppala conditions is 4.9 g VS dm-3 d-1, meaning that R100 will reach its maximum organic load around the year 2031. An OLR of 4.5-4.9 and an HRT of 12 days is optimal for R100, according to the present study. Keeping the anaerobic digestion process in balance is vital when it comes to the outcome of energy in the anaerobic digestion process. Pushing the process to produce more gas can become counterproductive since a high OLR can lead to process imbalance, which in turn leads to low biogas production. Imbalance in the digestion process can occur fast; therefore, the margin for overload in the anaerobic digestion process must be significant. The methane concentration in the converted biogas and the pH level in the reactor are the best stability parameters for the conditions at Käppala. Ammonia is the less efficient stability parameter since it did not predict or detect any instability during the experimental process. Furthermore, the OLR and HRT have a significant impact on the needed quantity for dewatering polymer. The higher digestion of organic material in the sludge, the bigger the need for the polymer to take care of the rest material.

The focused laser beam delivered by the high-power laser system PALS was used for laboratory simulation of high-energy-density events in a planetary atmosphere. Several model gas mixtures were prepared to mimic the mildly reducing early Earth's atmosphere (CO-N2-H2O) as well as the atmosphere of Saturn's moon Titan and the strongly reducing early Earth's atmosphere (CH4-N2-H2O). In situ investigation of transient species generated by the laser-induced dielectric breakdown in the gaseous mixtures was performed by optical emission spectroscopy (OES). Final products of laser-plasma initiated chemical reactions were identified and determined by advanced mass-spectrometry (SIFT-MS) and absorption FT-IR spectroscopy. High-power laser system SOFIA was utilized to simulate in our laboratory a high-velocity impact into the icy satellites of the outer planets of the Solar system. OES was engaged in probing the plasmas produced by the SOFIA beam focused on ice surfaces (water, methanol, formamide), while final products were analyzed by means of gas chromatography (GC/MS) and mass-spectrometry (SIFT-MS).