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Μια μεγάλη κατηγορία μεθόδων βελτίωσης – ενίσχυσης εδαφών είναι αυτή των ενέσεων. Η παρούσα έρευνα αποτελεί μέρος μιας εκτεταμένης προσπάθειας αντικατάστασης των χημικών διαλυμάτων με τα οικονομικότερα και αβλαβή προς το περιβάλλον ενέματα τσιμέντου και κυρίως τα αιωρήματα λεπτόκοκκων τσιμέντων, λόγω της δυνατότητας διείσδυσής τους ακόμα και σε πολύ λεπτόκοκκες άμμους. Στόχος της διατριβής αυτής είναι η συγκριτική αξιολόγηση της βελτίωσης των υδραυλικών και μηχανικών ιδιοτήτων των εμποτισμένων άμμων με χρήση ευσταθών και ασταθών αιωρημάτων , αφού το τελικό ποσοστό εξίδρωσης φάνηκε να συνδυάζει επιμέρους παραμέτρους ( λόγος νερού προς τσιμέντο και μέγεθων κόκκων τσιμέντου) και συνεπώς κρίθηκε καθοριστικός ο ρόλος του στην επιτυχία του εμποτισμού. Για τις ανάγκες της εργαστηριακής διερεύνησης χρησιμοποιήθηκαν τρεις τύποι τσιμέντου , ενώ εμποτίστηκαν τέσσερις καθαρές ασβεστολιθικές άμμοι διαφορετικής κοκκομετρικής διαβάθμισης καθώς και μία χαλαζιακής προέλευσης. Τα εμποτισμένα δοκίμια εξετάστηκαν σε δοκιμές διαπερατότητας και ανεμπόδιστης θλίψης και ακολούθησε παραμετρική διερεύνηση των μεγεθών αυτών για την ποσοτικοποίηση της επιρροής τους από μια σειρά παραμέτρων (λόγος νερού προς τσιμέντο, τελικό ποσοστό εξίδρωσης , κοκκομετρία και σύσταση άμμου, τύπος και κοκκομετρία τσιμέντων).Τελικά, ο λόγος νερού προς τσιμέντο αναδεικνύεται ως η σημαντικότερη παράμετρος επίδρασης των τιμών τόσο του συντελεστή διαπερατότητας όσο και της αντοχής σε ανεμπόδιστη θλίψη των εμποτισμένων άμμων. / Injections are one of the methods used for soil improvement and strengthening. This research is part of an extensive effort in order to replace chemical grouts with cheaper and harmless to the environment cement grouts; especially with microfine cement suspensions, because of their capability to penetrate even very fine sands. The aim of this study is to estimate the improvement of the hydraulic and mechanical properties of grouted sands using stable and unstable suspensions, since the bleed capacity seemed to combine individual parameters (water to cement ratio and cement grain size). Therefore, this factor was considered decisive for the success of grouting. During the laboratory investigation, three types of cement were used and four asbestolithic, clean sands of different grain gradation were grouted, as well as a quartz sand. Permeability and unconfined compression tests were performed on the grouted specimens. Then, a parametric study of the tests results was followed in order to quantify the influence of various parameters (water to cement ratio, bleed capacity, grain size and composition of sand, cement type and particle size). Finally, the water/cement ratio emerges as the most important parameter, which influences the values of both the coefficient of permeability and the unconfined compressive strength of the grouted sands.

Doctor of Philosophy / Department of Mechanical Engineering / Steven J. Eckels / Byron W. Jones / Poor air quality in commercial aircraft cabins can be caused by volatile organophosphorus (OP) compounds emitted from the jet engine bleed air system during smoke/fume incidents. Tri-cresyl phosphate (TCP), a common anti-wear additive in turbine engine oils, is an important component in today’s global aircraft operations. However, exposure to TCP increases risks of certain adverse health effects. This research analyzed used aircraft cabin air filters for jet engine oil contaminants and designed a jet engine bleed air simulator (BAS) to replicate smoke/fume incidents caused by pyrolysis of jet engine oil. Field emission scanning electron microscopy (FESEM) with X-ray energy dispersive spectroscopy (EDS) and neutron activation analysis (NAA) were used for elemental analysis of filters, and gas chromatography interfaced with mass spectrometry (GC/MS) was used to analyze used filters to determine TCP isomers. The filter analysis study involved 110 used and 74 incident filters. Clean air filter samples exposed to different bleed air conditions simulating cabin air contamination incidents were also analyzed by FESEM/EDS, NAA, and GC/MS. Experiments were conducted on a BAS at various bleed air conditions typical of an operating jet engine so that the effects of temperature and pressure variations on jet engine oil aerosol formation could be determined. The GC/MS analysis of both used and incident filters characterized tri-m-cresyl phosphate (TmCP) and tri-p-cresyl phosphate (TpCP) by a base peak of an m/z = 368, with corresponding retention times of 21.9 and 23.4 minutes. The hydrocarbons in jet oil were characterized in the filters by a base peak pattern of an m/z = 85, 113. Using retention times and hydrocarbon thermal conductivity peak (TCP) pattern obtained from jet engine oil standards, five out of 110 used filters tested had oil markers. Meanwhile 22 out of 74 incident filters tested positive for oil fingerprints. Probit analysis of jet engine oil aerosols obtained from BAS tests by optical particle counter (OPC) revealed lognormal distributions with the mean (range) of geometric mass mean diameter (GMMD) = 0.41 (0.39, 0.45) [mu]m and geometric standard deviation (GSD), [sigma][subscript]g = 1.92 (1.87, 1.98). FESEM/EDS and NAA techniques found a wide range of elements on filters, and further investigations of used filters are recommended using these techniques. The protocols for air and filter sampling and GC/MS analysis used in this study will increase the options available for detecting jet engine oil on cabin air filters. Such criteria could support policy development for compliance with cabin air quality standards during incidents.

Helicopters have now become an essential part for civil and military activities, for the next few years a significant increase in the use of this mean of transportation is expected. Unlike many fixed-wing aircraft, helicopters have no need to be pressurized due to their operating at low altitudes. The Environmental Control Systems (ECS) commonly used in fixed-wing aircraft are air cycle systems, which use the engine compressor’s bleed flow to function. These systems are integrated in the aircraft from inception. The ECS in helicopters is commonly added subsequently to an already designed airframe and power plant or as an additional development for modern aircraft. Helicopter engines are not designed to bleed air while producing their rated power, due to this a high penalty in fuel consumption is paid by such refitted systems. A detailed study of the different configurations of ECS for rotorcraft could reduce this penalty by determining the required power resulting from each of the system configurations, and therefore recommend the most appropriate one to be implemented for a particular flight path and aircraft. This study presents the conducted analysis and subsequent simulation of the environmental control system in a selected representative rotorcraft: the Bell206L-4. This investigation seeks to optimize the rotorcraft’s power consumption and energy waste; by taking into consideration the cabin heat load. It consequently aims to minimize these penalties, achieving passenger comfort, an optimally moist air for equipment and a reduction in the environmental impact. For the purpose of this analysis a civil aircraft was chosen for a rotary-wing type. This helicopter was analysed with different air-conditioning packs complying with the current airworthiness requirements. These systems were optimized with the inclusion of different environmental control models, and the cabin heat load model, which provided the best air-conditioning for many conditions and mission scopes, thus reducing the high fuel consumption in engines and hence the emission of gases into the environment. Each of the models was computed in the Matlab-simulink® software. Different case studies were carried out by changing aircraft, the system’s configurations and flight parameters. Comparisons between the different systems and sub-systems were performed. The results of these simulations permitted the ECS configuration selection for optimal fuel consumption. Once validated the results obtained through this model were included in Rotorcraft Mission Energy Management Model (RMEM), a tool designed to predict the power requirements of helicopter systems. The computed ECS model shows that favourable reductions in fuel burn may be achievable if an appropriated configuration of ECS is chosen for a light rotorcraft. The results show that the VCM mixed with engine bleed air is the best configuration for the chosen missions. However, this configuration can vary according to the mission and environment.

Persons with severe hemophilia A exhibit significant variations in clinical phenotype; approximately 10% are milder bleeders. This study explored factors that might contribute to this inter-patient heterogeneity. Using a multi-center prospective study following boys with severe hemophilia A on a tailored primary prophylaxis regimen, age at first joint bleed, body mass index, protocol adherence and family activity level were modeled on the age at escalation from once-weekly to twice-weekly and alternate day infusions. Escalation, based on bleeding frequency, served as a surrogate marker of bleeding severity. We also assessed the roles of clinical and hemostatic parameters in predicting age at first joint bleed using a cross-sectional study. Results suggest that a delayed first joint bleed indicates later escalation (milder bleeding pattern) and that a longer lag time is associated with an earlier onset of joint bleeding. Larger studies are needed to definitively identify predictors of clinical heterogeneity in these patients.

Persons with severe hemophilia A exhibit significant variations in clinical phenotype; approximately 10% are milder bleeders. This study explored factors that might contribute to this inter-patient heterogeneity. Using a multi-center prospective study following boys with severe hemophilia A on a tailored primary prophylaxis regimen, age at first joint bleed, body mass index, protocol adherence and family activity level were modeled on the age at escalation from once-weekly to twice-weekly and alternate day infusions. Escalation, based on bleeding frequency, served as a surrogate marker of bleeding severity. We also assessed the roles of clinical and hemostatic parameters in predicting age at first joint bleed using a cross-sectional study. Results suggest that a delayed first joint bleed indicates later escalation (milder bleeding pattern) and that a longer lag time is associated with an earlier onset of joint bleeding. Larger studies are needed to definitively identify predictors of clinical heterogeneity in these patients.

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Denna studie utgår från transpersoners och icke-binära personers erfarenheter av lajvande i Sverige under 2000-talet. Lajv är en typ av performance, liknande improviserad teater utan publik, där deltagarna gestaltar och förkroppsligar olika karaktärer, en roll eller alternativ identitet. Även om lajvs potential att förändra har tidigare studerats har ingen forskning gjorts om transpersoners erfarenheter av hur lajv och karaktärer har förändrat dem. Denna studie undersöker därför hur lajv och erfarenheter av att förkroppsliga karaktärer har påverkat hur de ser på sin könsidentitet och använder sig av könsuttryck i vardagen. I fokus står deltagarnas aha-upplevelser om sitt kön före, under, kring och efter lajv. Med intervjuer och queer fenomenologi visar studien att lajvande och karaktärer har hjälpt dem att hitta, utforska, testa och orientera sig mot nya könslinjer, könsidentiteter och könsuttryck samt gett dem verktyg att börja följa dessa könslinjer i vardagen. Studien visar även hur de har hindrats och hjälpts av andra lajvare, samt hur gränsen mellan lajv och vardag läcker och transformerar. Studiens resultat bidrar till en ökad kunskap om hur lajvande kan ha en förmåga att förändra och hur svenska lajvkulturen har utvecklats under 2000-talet. / This thesis concerns trans and non-binary persons’ experiences of live action role-playing (larp) in Sweden during the last 20 years. Larp is a form of performance, similar to improvised theater without any external audience, where the participants (larpers) play and embody characters. The characters are similar to theater characters, but are also a form of persona or alternative identity for the larpers. Although earlier research has shown that larp has a potential to transform and change larpers, little research has been done on transpersons’ experiences of how larping and characters have changed them. The purpose of this thesis is to analyse how larping and experiences of embodying characters have affected how they understand their own gendersex and use gendered expressions, clothes, and behaviors in everyday life. A central part of the analysis is the participants' feeling of wonder over their gendersex before, during, around, and after larping. By using interviews, queer phenomenology, and the concept of bleed, the study shows how larping and characters have helped them to find, explore, try, and orient themselves toward new gender lines, gendersexes and gendered expressions and also given them tools to help them following these new gender lines and embody their gendersex in everyday life. Furthermore, the study shows how they have been hindered and helped by other larpers, and how the borders between the larp worlds and the world of everyday life are porous and transformative. The findings of the study gives new insights of transpersons’ experiences of larping. Furthermore, the results deepen our knowledge of larping’s transformative potential, how role-playing can be used in identity processes, and how the Swedish larping community has evolved during the 21th century.

This thesis concerns biogas-operated fuel cells. Fuel cell technology may contribute to more efficient energy use, reduce emissions and also perhaps revolutionize current energy systems. The technology is, however, still immature and has not yet been implemented as dominant in any application or niche market. Research and development is currently being carried out to investigate whether fuel cells can live up to their full potential and to further advance the technology. The research of thesis contributes by exploring the potential of using fuel cells as energy converters of biogas to electricity. The work includes results from four different experimental test facilities and concerns experiments performed at cell, stack and fuel cell system levels. The studies on cell and stack level have focused on the influence of CO, CO2 and air bleed on the current distribution during transient operation. The dynamic response has been evaluated on a single cell, a segmented cell and at stack level. Two fuel cell systems, a 4 kW PEFC system and a 5 kW SOFC system have been operated on upgraded biogas. A significant outcome is that the possibility of operating both PEFCs and SOFCs on biogas has been established. No interruptions or rapid performance loss could be associated with the upgraded biogas during operation. From the studies at cell and stack level, it is clear that CO causes significant changes in the current distribution in a PEFC; air bleed may recover the uneven current distribution and also the drop in cell voltage due to CO and CO2 poisoning. The recovery of cell performance during air bleed occurs evenly over the electrode surface even when the O2 partial pressure is far too low to fully recover the CO poisoning. The O2 supplied to the anode reacts on the anode catalyst and no O2 was measured at the cell outlet for air bleed levels up to 5 %. Reformed biogas and other gases with high CO2 content are thus, from dilution and CO-poisoning perspectives, suitable for PEFC systems. The present work has enhanced our understanding of biogas-operated fuel cells and will serve as basis for future studies. / QC20100708

Grease is among the most widely used lubricants in rolling element bearings. Proper understanding of the effect of lubrication due to grease aging can provide a significant increase in the life of the engineering systems. However, at present, there is no sufficient understanding of the grease aging effect in rolling elements bearing. This restricts the optimal usage of the bearing and timely monitoring of the grease. The current research work tries to address this issue with an experimental investigation. This project studies the behavior of 4 types of greases in rolling elements bearings for various operating conditions by recording the temperature and acoustic emission data. The aged samples were prepared to keep in the oven at 150 °C for a series of time duration letting it go through the chemical changes and thermal degradation. Tests were carried out in a test rig with the different levels of oxidized greases for 5 hrs time. And the effects in bearing temperature, acoustic emission were recorded. This is an investigation to analyze the effects of grease composition and aging in rolling elements lubrication by means of acoustic emission and bearing temperature. The IR spectroscopy was carried from the samples collected from the oven in order to understand the change in lubricant composition. The results show that the grease with di-urea thickener and base oil of synthetic ether and polyolester gives the best bearing temperature and acoustic emission behavior compared to the other grease type. The possibility of using the acoustic emission and temperature data to monitor the grease aging is also presented. Along with this, the possibility of using the AE statistical methods, AE count method, and energy plot were also explored to relate with the degree of aging.