Microbial mats exist in freshwater pools atop the Ward Hunt and Markham ice shelves in the Canadian high Arctic. In this study, culture-dependent and culture-independent techniques were used to describe the microbial diversity and activity of these mat communities.Bacterial and archaeal 16S rRNA gene clone libraries were constructed from Markham and Ward Hunt mat samples. Bacterial libraries from both mats had high diversity, though the Markham library appeared more diverse than the Ward Hunt library. Over 95% of sequences in both bacterial libraries, and all isolates from both mats, grouped within the phyla Bacteroidetes, Proteobacteria, and Actinobacteria. Archaeal diversity appeared low in both mats. Only one phylotype, potentially representing a novel Euryarchaeota, was observed in both archaeal libraries. Populations in both communities showed activity at subzero temperatures, with growth of isolates at -5°C and detectable metabolic activity at -10°C, measured by radiorespiration assays of mat microcosms.

Welded wire mesh has been used in the past as soil reinforcement in the construction of reinforced soil embankments. Involved in the design of these embankments is the external and internal stability. The internal stability has two failure mechanisms; tension failure and pullout failure of the welded wire mesh. This paper presents the results of laboratory tests on different sizes of welded wire mats embedded in different types of soils. These tests were performed on mats that are much larger than in previous tests. These tests measured the pullout resistance as a function of the number of embedded wires, the diameter of the wire, and the overburden pressure. This data is plotted to allow design of reinforced soil embankments in various types of soils and to compare the results with theoretical relationships.

Uppsatsen syftar till att undersöka hur hållbarhetsperspektivet kan inkluderas i svenskämnet, då många ungdomar känner en oro för klimatförändringar och för att hållbarhet är en del av de globala målen och skolans värdegrund. För att kunna undersöka detta har en ekokritisk och didaktisk närläsning genomförts av Mats Strandbergs roman Slutet. Romanen låter läsare följa Simon och Lucinda, två ungdomar som lever i en värld som är på väg att gå under.  Resultaten visar att boken främst har fokus på människan. Människan och hens ansvar gentemot naturen är viktigt, men även människans känslor kring det hemska som ska hända i världen de lever i. Naturen befinner sig i periferin av människan. Närläsningen visar att boken har potential att vara underlag för diskussioner i klassrummet kring existentiella frågor och oroskänslor som ungdomar kan ha inför framtiden.

To date, most studies on the effectiveness of geotextiles on soil erosion rates were conducted in laboratory experiments for <1 h. Hence, at Hilton, East Shropshire, UK, this study investigated the effectiveness of palm-mat geotextiles (Borassus and Buriti mats) in reducing rainsplash erosion, runoff and soil loss and changing selected soil properties under field conditions over two years (January 2007-January 2009). Mat-cover effects on rainsplash erosion were studied in two sets on a loamy sand soil (0o slope). In both sets, six randomly-selected plots (each 1 m2) were completely matcovered and six were bare. Unlike Buriti mats, Borassus mat-cover on bare soil significantly (P<0.001) decreased rainsplash erosion (by ~89%). Duplicate runoff plots (10 x 1 m on a 15o slope) had five treatments (bare, permanent grass, Borassus completely-cover, Borassus buffer strip and Buriti buffer strip). Using Borassus buffer strips (area coverage ~10%) on bare soil decreased runoff by ~71% (P>0.05) and soil erosion by ~92% (P<0.001). Borassus buffer strip, Buriti buffer strip and Borassus completely-covered plots had similar effects in decreasing runoff and soil loss. However, the longevity of Borassus mats was ~twice that of Buriti mats. Despite physical protection, runoff control and sediment entrapment, biomat buffer zones may considerably alter and protect flow direction by presenting barriers and creating several cross-drains. Except Borassus completely-covered plots, all plots had significant (P<0.05) increases in topsoil (0-5 cm) bulk density and decreased aggregate stability. However, buffer strips were more effective in trapping fine particles than Borassus completely-covered plots. No treatments had significant (P>0.05) effects on changes in pH, soil organic matter, total soil carbon or N. Plots with Borassus mats significantly (P<0.05) increased total P and decreased total Ca. Treatments had no significant effects on changes in total S, Mg, Zn, Cu, Fe, Mn, Mo or Cl concentrations. Borassus buffer strips can effectively conserve soil and water and improve and maintain selected soil properties, with results similar to Borassus completely-covered plots. The mechanisms explaining the effectiveness of buffer zones require further studies under varied pedo-climatic conditions.

The increase of new and ever more stringent emission legislation has brought about with it a surge in the demand for more sustainable automotive solutions. This has particularly been the case for automobiles, including heavy-duty vehicles like trucks and buses, with internal combustion engines, which now require the design and manufacturing of more durable and reliable components. An important component of internal combustion engine automobiles, which helps achieve this target, is the exhaust after-treatment system. Exhaust after-treatment systems are usually equipped with some type of catalytic converter, treating the combustion gases from the engine exhaust manifold to reduce the concentration of pollutants. The catalytic converter assembly usually consists of an assembly of an outer metallic canning, an inner substrate and a packaging mat in between the two. The packaging mat, commonly known as the support mat, is an important component in the assembly, protecting the ceramic substrate from road induced and thermal loads, thereby preventing any damage to the latter. This thesis involves further development of a finite element model for the support mat that could be used in catalytic converter simulations with a reasonable degree of accuracy and reliability. In line with this objective, the characteristic mechanical response of the mat is first studied through a series of material tests: namely compression, friction, and shear tests. Different non-linear material models like hyperfoam, hyperelastic and viscoelastic models, are then created in ABAQUS to simulate the mat behaviour in the tests. The material model correlating most closely with the test is then implemented in the simulation of the assembly process, canning of a catalytic converter. This report includes the material tests conducted on the mats in new and aged condition, findings of the characteristic response of the mats in these tests as well as the constitutive material modelling and finite element simulations carried out for correlation with test data from the new mats. The most appropriate material model was also implemented in a canning assembly simulation to evaluate the efficacy of the material model in predicting the mat pressure, gap bulk density, and push-in force.

MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) is a small satellite that will belaunched in 2019. The satellite will fly in low-earth orbit obtaining data from Noctilucent Clouds andthe oxygen Airglow phenomenon. The satellite is equipped with CCDs prepared to capture images ofthe mesospheric events. The image signal needs to be processed by an analog chain before reachingthe ADC. Satellites in orbit and their components are susceptible of being affected by ionizingradiation originated from the space.Electronic devices are affected in an ionization process, interfering with their functionality andperformance. Tests need to be done over the MATS components to guarantee that the transmissionof the signals is not affected by the radiation and the satellite is able to maintain its performance. Theaim of this thesis is to explain the tests carried to analyze the different MATS components at similarradiation conditions as the real mission and to find the most adequate substitutes in case of the nonsuitabilityof the original components. / MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) är en satellit som kommer attskjutas upp i 2019. Satelliten ska flyga i en låg omloppsbana och avbilda nattlysande moln och syreluftsken (airglow). Satelliten har CCD detektorer för att ta bilder av dessa fenomen i mesosfären.Sensorernas signaler behöver behandlas av en analog kedja innan de når ADC. Satelliter på bana ochderas komponenter kan påverkas av joniserande strålning från rymden.Elektronikenheter påverkas i en joniseringsprocess, som stör deras funktionalitet och prestanda.Tester måste göras över MATS komponenter för att garantera att överföringen av signalerna intepåverkas av strålningen och satelliten kan bibehålla sin prestanda. Syftet med detta arbete är attförklara de tester som utförts för att analysera de olika MATS-komponenterna vid liknandestrålningsförhållanden som det verkliga uppdraget och att hitta de mest lämpliga ersättningar ifall deursprungliga komponenterna visar sig inte vara lämpliga.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Polymeric nanofibrous membranes that act as surfaces offer two compelling properties; they have extremely large surface areas that can be modified and they can offer multiple reactive sites depending on which polymer they were electrospun from. Combining nanofibrous surfaces such as these with photochromic dyes can give remarkable, light responsive materials. In this study, a terpolymer was electrospun and crosslinked (to impart insolubility to the material) to produce a nanofibrous mat that contained surface secondary-hydroxyl units and benzyl chloride units, from which monomers could grow using surface-initiated atom transfer polymerization (SI-ATRP). The surface was further fluorinated though the secondary-hydroxyl moieties to produce a hydrophobic crosslinked nanofibrous surface. n-Butyl acrylate and a photochromic spiropyran dye were copolymerized from the surface using SIATRP, in order to produce a surface that exhibited reversible adhesion towards a water droplet using ultraviolet and visible light as a stimulus to change between the two states. This in principle would allow the droplet to roll off and stick to the surface respectively. Although the surface displayed a colour change when switched, proving that the SI-ATRP had taken place, the droplet of water remained attached to the surface in both states. / AFRIKAANSE OPSOMMING: Polimeriese nanovesel membrane wat dien as oppervlaktes bied twee aantreklike eienskappe; hulle het baie groot oppervlakareas wat gemodifiseer kan word en hulle bied veelvuldige reaktiewe punte, afhangende van die polimeer waarvan hulle ge-elektrospin is. Deur sulke nanovesel oppervlaktes met fotochromiese kleurstowwe te kombineer, kan uitstekende lig reagerende materiale verkry word. In hierdie studie is ‘n terpolimeer ge-elektrospin en daarna gekruisbind (om die materiaal onoplosbaar te maak) om ‘n nanovesel web te kry wat oppervlak sekondêre-hidroksiel en benzielchloried eenhede bevat. Monomere kan dan vanaf hierdie eenhede groei deur middel van oppervlak-geïnisieerde atoomoordrag polimerisasie (OI-AOPR). Die oppervlak was verder gefluorineer via die sekondêre-hidroksiel eenhede om ‘n hidrofobiese, gekruisbinde nanovesel oppervlak te vorm. n-Butielakrilaat en ‘n fotochromiese spiropiraan kleurstof is gekopolimeriseer vanaf die oppervlak deur middel van OI-AORP om sodoende ‘n oppervlak te skep wat omkeerbare adhesie van ‘n water druppel gee as ultraviolet en sigbare lig as stimulus gebruik word om tussen die twee toestande te wissel. In beginsel sal die water druppel vanaf die oppervlak kan afrol én daaraan vassit, afhangende van die toestand van die oppervlak. Alhoewel die oppervlak van kleur verander het met die wisseling tussen die twee toestande, wat as bewys dien dat OI-AORP wel plaasgevind het, het die druppel water bly vassit aan die oppervlak in beide toestande.

Barrier fabrics laminated with nanofiber membranes are used in protective textiles due to their ability to achieve high breathability or water vapor transmission rate (WVTR) while maintaining required barrier properties. The objective of this thesis is to investigate the factors impacting nanofiber membrane breathability. To achieve this objective, the effect of test conditions on breathability, and the relationship between fiber diameter, web porosity and breathability were explored. Nanofiber membranes were solution-spun by electrospinning from 15wt% and 20wt% PA6 solution concentrations, and by forcespinning from 20wt% and 25wt% concentrations. Three web area densities were made from each spinning method and solution combination: 5GSM, 10GSM and 15GSM. In order to investigate the impact of measurement conditions, breathability of all samples was measured by upright cup method (ASTM E96B) at two relative humidity levels (20% and 50%), and three air flow velocity levels (300fpm, 500fpm and 700fpm). The results showed that WVTR of all samples increased significantly when decreasing humidity or increasing air flow velocity. Webs with a lower density (5GSM or 10GSM) had higher changes of WVTR than those with a higher density (10GSM or 15GSM). These results indicate an interaction between the ambient conditions and the nanoweb structure, whereby conditions that are more conducive to water vapor transmission, such as 20%RH and 700fpm, are more discriminant between membranes. Both electropspun and forcespun membranes processed from the lower concentration solutions (15wt%, and 20wt%, respectively) exhibited smaller fiber diameters and smaller mean pore size. Overall, WVTR values varied with membrane thickness, and with solution concentration following a similar pattern as porosity. These effects were more accentuated for the forcespun samples, which had considerably larger pores (2811-5230nm) than the electrospun counterparts (163-298nm). Furthermore, samples forcespun by 20wt% solution were found to have clearly higher WVTR (1587-2194g/m²/24h at 700fpm) than electrospun samples (1526-1614g/m²/24h at 700fpm). This can be explained by the significant difference of pore size between electrospun and forcespun webs. It was concluded that breathability of forcespun samples, particularly those low density ones, could be effectively adjusted by solution concentration and is more sensitive to change of test conditions than that of electrospun webs. / text

Syftet med studien var att studera hur ett samtal om gemensamt beslutsfattande går till när en patient, Case manager och professionella träffas enskilt eller i resursgrupp och samtalar med varandra om vårdplanen. Det var en etnografisk studie där samtal inom en psykiatrisk verksamhet representerade det fält som studerats genom metoden deltagande observation. Resultatet visade att plats, form, tid, tempo, och rytm hade betydelse för samtalets kvalitet liksom att det fanns en ansvarsfördelning i samtalet som bland annat karaktäriserades av att bli bemött med förståelse för en livssituation som innebar ett lidande. Andra faktorer som påverkade kvalitén var hur de professionella ställde frågor, inväntade svar och avslutade samtalet. Men även vad som händer när samtalet brister och att inte kunna berätta och fråga under samtalet. Det fanns dock situationer där personen kunde berätta och uttrycka sig i samtalet och med stöd av samtalsmatta kunde uttrycka egna åsikter, önskningar och behov. / The purpose of the study was to establish how a collective decision can be made when the individual and the case manager meet with the technical experts, either by themselves or as part of a wider focus group, to discuss the treatment plan. It was an ethnographic study conducted by observing psychiatric conversations. The findings of the study confirmed that the location, format of the meeting and the pace at which the meeting was conducted, directly influenced the quality of the discussion. It was also important for the participants to be sympathetic towards the individual’s personal situation and understand the difficulties faced by the individual on a daily basis. The questioning technique used by the technical experts and how the discussion was concluded, was also important. Also, what happens when the conversation goes off track and when the individual is unable to give information and ask questions. There were examples of situations where the individuals could express themselves constructively, using the talking mat, and could give their view and confirm needs and desires. In order to make their voices heard, they need to be clear what they want and must be able to argue their case.

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