Sökresultat

This thesis addresses powder manufactured (P/M) components, with special attention to the compaction process and to the sensitivity to damage accumulation due to fatigue within powder compacted specimens. Three dimensional simulations of the compaction process have been performed, using an explicit dynamic dilatant finite strain finite element code supplemented with the effects from contact fricti

Following a radiological or nuclear emergency event, there is a need for quick and reliable dose estimations of potentially exposed people. In situations where dosimeters are not readily available, the dose estimations must be carried out using alternative methods. In the present study, the optically stimulated luminescence (OSL) properties of tooth enamel and different dental repair materials hav

Popular Abstract in Swedish Total höftledsplastik är en vanlig och mycket framgångsrik behandling av smärttillstånd i höftleden. Enligt svenska höftplastikregistret opererades 12651 patienter år 2002 men 1056 patienter fick samma år genomgå ett utbyte av sin höftledsprotes (revision). Att höftleden vrids ur led (luxation) upprepade gånger eller infektion kan vara orsaken till revision men det vanlTotal hip arthroplasty is a very successful procedure. Despite this fact, however, a certain portion of patients has to be revised. One major reason for revision is the wear of the polyethylene leading to loosening and osteolysis. The overall aim of this thesis was to evaluate linear wear and migration of cemented, all - polyethylene sockets and polyethylene liners in total hip arthroplasty. The a

Popular Abstract in Swedish Membranteknik är en separationsteknik där stora partiklar skiljs av från mindre partiklar m.h.a. ett membranfilter. I min forskning har jag tittat på hur membranfiltrering kan användas inom bioteknikindustrin. Jag har tittat på hur mjölksyra kan renas upp från en lösning av jäst "vetemjölsvälling" samt hur första steget i uppreningen av protein A från en industriellt prMembrane filtration is a very gentle separation technique and can be used at low temperatures. This makes it suitable for liquids that contain micro-organisms and/or are heat sensitive, which is often the case in liquids processed in the field of biotechnology. However, one drawback is that these liquids are often very complex, which is a disadvantage when using membrane technology as it makes the

Proton exchange membrane fuel cell (PEMFC) systems have been investigated as alternative power sources for the stationary and automotive applications. However, they do not appear on the market yet. One of the main reasons is the difficulty of the water/thermal management in the system. Several water recovery schemes have been proposed to overcome this difficulty and to simplify the system configur

Popular Abstract in Swedish För att förstå tillväxten av den kontinentala jordskorpan är det nödvändigt att kunna uppskatta balansen mellan juvenilt bidrag från manteln, infra-krustal omarbetning av jordskorpa och transport av krustalt material tillbaka till manteln. Sedan början av seklet har användandet av in situ U–Pb, Lu–Hf och O-isotop analyser av mineralet zirkon som ett verktyg för att adreTo understand the growth of continental crust, the balance between juvenile mantle derived extraction, infracrustal reworking and crustal recycling, needs to be estimated. Since the beginning of the century, the use of coupled in situ zircon U–Pb, Lu–Hf and O isotope analyses as a tool to address these questions have increased exponentially. Numerous compilations of ever growing datasets have been

Experimentally determined activation energies of propane dehydrogenation catalyzed by ZSM-5 zeolites have been used to test the SET theory. The basis of this theory is that the catalyst system transfers vibrational energy via a resonance process to a specific vibration mode of the reacting molecule. Being excited up to a certain number of vibrational quanta the molecule is brought to reaction. By

Popular Abstract in Swedish Extrakt från växten Artemisia annua har dokumenterats för sina anti-malaria egenskaper. Substansen är en mycket effektiv medicin mot malaria och hjälper även mot de former där multi-resistens utvecklats.1979 presenterades strukturen på den aktiva substansen. Den benämns artemisinin och är uppbygd av femton kol innehållandes en peroxid-brygga (två syre kopplade till varaPlants produce a multitude of different compounds that may have biotic effects. Artemisia annua, produces a compound used as a drug against multi-drug-resistant strains of Plasmodium falciparum, the parasite causing malaria. The compound, artemisinin, is a sesquiterpene and is an essential component for the production of artemisinin drugs against malaria. In a first critical step of the biosynthes

Popular Abstract in Swedish Hjärnan ansvarar för styrningen av vårt beteende. Exempelvis kan skador på hjärnan vara förödande för vår motorik eller förändra vår personlighet. Hur hjärnan exakt ger upphov till vårt beteende är i huvudsak okänt men hjärnans betydelse för vissa delar av vårt beteende har studerats genom att bryta ner vårt beteende i avgränsade, identifierbara beståndsdelar. Ett avgrä