The use of an attached sunspace is one of the most popular passive solar heating techniques. One of the main drawbacks of the sunspace is getting over heated by the sun energy during the hot season of the year. Even in northern climates overheating could be problematic and there is a considerable cooling demand. Shading is one of the most efficient and cost effective strategies to avoid overheating due to the high irradiation especially in the summer. Another strategy is using ventilation system to remove the excess heat inside the sunspace. However this rejected energy can be captured and stored for future energy demands of the sunspace itself or nearby buildings. Therefore the Solar blind system has been considered here for the shielding purpose in order to reduce the cooling demand. By considering the PV/T panels as the solar blind, the blocked solar energy will be collected and stored for covering part of the heating demand and the domestic hot water supplies of the adjacent building.  From a modeling point of view, the sunspace can be considered as a small-scale closed greenhouse. In the closed greenhouse concept, available excess heat is indeed utilized in order to supply the heating demand of the greenhouse itself as well as neighboring buildings. The energy captured by PV/T collectors and the excess heat from the sunspace then will be stored in a thermal energy storage system to cover the daily and seasonal energy demand of the attached building. In the present study, a residential building with an attached sunspace with height, length and width of 3, 12 and 3.5 meters respectively has been assumed located in two different locations, Stockholm and Rome. Simulations have been run for the Solar blind system integrated with a short-term and a long-term TES systems during a year to investigate the influence of the sunspace equipped with a PV/T Solar blind on the thermal behavior of the adjacent building. The simulated results show that the Solar blind system can be an appropriate and effective solution for avoiding overheating problems in sunspace and simultaneously produce and store significant amount of thermal energy and electricity power which leads to saving considerable amount of money during a year.

To gain an understanding of the ecology of drift algae in the Indian River Lagoon system along the east coast of central Florida, four questions were addressed: 1) What is the composition and rate of accumulation of drift? 2) How much movement and turnover occurs within drift accumulations? 3) Do growth rates differ for drift versus attached algae? 4) Is there a difference in photosynthetic performance in drift versus attached algal species? Manipulative field and laboratory experiments were conducted to address these questions with the green macroalga Codium decorticatum and the red macroalga Gracilaria tikvahiae. Changes in pigment concentration and biomass were used as indicators of acclimation from an attached to drift state in Gracilaria tikvahiae and Codium decorticatum. Short-term physiological changes as demonstrated by electron transport rate (ETR) were also used as indications of acclimation from an attached to drift state in C. decorticatum. Composition and rate of accumulation of drift varied by season. While both transport and turnover of drift occurred, turnover within drift accumulations occurred at low rates and was significantly lower in the spring during decreased flow rates. There were no significant differences in growth or pigment concentrations in drift versus attached G. tikvahiae or C. decorticatum. In addition, there were no apparent physiological acclimations to a drift state in C. decorticatum.

Let R be a non-zero commutative Noetherian ring with unit 1 ≠ 0, a be an ideal of R, and M and N be R-modules. This thesis makes a contribution to the study of generalized local cohomology modules, namely Hia (M;N), with applications for the study of attached primes, torsion product and extension functors, and integral closures and multiplicities relative to Artinian modules. In particular, we obtained results on the following topics: counting the number of non-isomorphic top generalized local cohomology modules, conditions to finiteness, cofiniteness, artinianess and representability of generalized local cohomology modules, torsion product and extension functors applied to R-modules, and conditions to equality between some types of integral closures and multiplicities. / Sejam R um anel Noetheriano comutativo com unidade 1 ≠ 0, a um ideal de R e M e N módulos sobre R. Nessa tese, fazemos contribuições ao estudo dos módulos de cohomologia local generalizada, a saber Hia (M;N), com aplicações ao estudo dos ideais primos anexados de R, funtores torção e extensão, e fecho integral e multiplicidades relativos a módulos artinianos. Em particular, estabelecemos resultados nos seguintes temas: contar o número de módulos de cohomologia local generalizados no topo não isomorfos; condições para os módulos de cohomologia local e os funtores torção e extensão aplicados a R-módulos terem características finitas (finitamente gerado, finitos primos associados, etc), serem cofinitos, serem artinianos e serem representáveis; e condições para a igualdade entre tipos de fechos integrais e multiplicidades.

Four studies including ten experiments adresses interrelations between some major and classical issues in visual perception: 3-D perception, colour constancy, colour perception and colour vision deficiencies. The main experimental paradigm to investigate the issues is within that of simulated shape from shading. 3-D impressions are induced by projecting space-modulated illuminations onto flat surfaces (displays), varying the colours and layout of the displays and the colour and modulation of the illumination. Study I includes four experiments investigating three types of space- modulated illumination. All experiments confirmed earlier findings that chromatic colour and complex display layout with reflectance edges crossed by illumination edges enhances shape from shading. In Study II the impressions of shape from shading and real 3-D objects were compared between persons with deutan colour vision deficiencies and normals. As predicted, the deutans show fewer and less distinct 3-D impressions in situations with their specific "problem colours" red and green. They also show a generally lower tendency for 3-D impressions, interpreted as a generally weaker colour constancy. Study III presents the AMBEGUJAS phenomenon; a novel twofold ambiguous shape from shading situation, continuously alternating between two different 3-D impressions coupled with different colour attributions. One solution is of an object with two clear surface colours, the other one of an object with greyish (desaturated) colours in coloured illumination which means classical colour constancy. The phenomenon illustrates the visual processes of separating reflectance and illumination characteristics and may provide a useful experimental setting to study colour constancy. In Study IV the AMBEGUJAS phenomenon is found to be robust as to chromaticness and different luminance contrasts for both normals and deutans. However, the deutans show slower shifts between percepts and a less pronounced desaturation of colour, which indicates a weaker colour constancy. The studies add evidence to the contribution of colour to 3-D shape perception, validated in a novel way by the results on "colour-blinds". The AMBEGUJAS phenomenon provides further support that the factors affecting shape from shading and the deutans different impressions are to be understood with reference to colour constancy. The deutans different impressions compared to normals are remarkable per se, but probably with very limited implications to everyday life. / <p>Diss. (sammanfattning) Umeå : Umeå university, 1996, härtill 4 uppsatser</p> / digitalisering@umu

Le processus de photo-oxydation induite a été étudié au laboratoire en conditions contrôlées à l’aide de cultures non-axéniques sénescentes de diverses souches phytoplanctoniques. Le suivi de la dégradation de l’acide cis-vaccénique (marqueur bactérien) nous a permis de confirmer l’existence d’un flux d’1O2 des phytodétritus vers les bactéries attachées et de mettre en évidence une corrélation significative entre l’état de photodégradation des bactéries et la concentration en chlorophylle a (photosensibilisateur) des cellules phytoplanctoniques. Nous avons également démontré que les photoproduits formés au sein des bactéries et du phytoplancton (hydropéroxyacides) étaient rapidement dégradés dans nos conditions expérimentales en cétoacides et hydroxyacides correspondants. L’effet des matrices siliceuses et carbonatées sur l’efficacité du transfert d’1O2 des phytodétritus vers les bactéries attachées a également été étudié. Les résultats ont montré que contrairement aux matrices carbonatées (coccolithes) des coccolithophoridés, les matrices siliceuses (frustules) des diatomées, inhibaient fortement le transfert de l’1O2 limitant ainsi la photodégradation des bactéries attachées. L’étude des effets de l’1O2 sur la dynamique des communautés bactériennes attachées aux phytodétritus a montré que près de 90 % des bactéries attachées étaient mortes dans une culture d’E. huxleyi en phase stationnaire prolongée et que les bactéries vivantes étaient dominées par des bactéries pigmentées dont la résistance à l’1O2 serait liée à leurs fortes teneurs en caroténoïdes. Des analyses en DGGE ont montré que la diversité bactérienne était affectée par l’irradiation lumineuse. / Induced photo-oxidation processes were studied in the laboratory under controlled conditions using non- axenic senescent cultures of several phytoplankton strains. The monitoring of the cis- vaccenic acid (bacterial marker) degradation allowed us to confirm the existence of a 1O2 flow from phytodetritus to the attached bacteria and to highlight a significant correlation between the photodegradation state of bacteria and chlorophyll a (photosensitizer) concentration in phytoplankton cells. We also demonstrated that photoproducts formed, within bacteria and phytoplankton (hydroperoxyacids), were rapidly degraded under our experimental conditions into corresponding ketoacids and hydroxyacids. The effect of siliceous and carbonate matrices (mineral polar medium) on the efficiency of singlet oxygen transfer from phytodetritus to the attached bacteria was also studied. Results showed that, in contrast to the carbonate matrix (coccoliths) of coccolithophorids, siliceous matrix (frustules) of diatoms, strongly inhibited the transfer of 1O2, thus limiting the photodegradation of attached bacteria. The study of the effects of 1O2 on the dynamics of bacterial communities attached to phytodetritus showed that nearly 90 % of attached bacteria were killed in a culture of E. huxleyi in late stationary phase and showed that living bacteria were dominated by pigmented bacteria whose resistance toward 1O2 results likely from their high carotenoid contents. DGGE and lipid tracer analyses showed that bacterial diversity was significantly affected by light irradiation.

Les biofilms bactériens, communautés multicellulaires adhérentes à une surface et enrobées d’une matrice extracellulaire, sont cruciaux pour le maintien de la plupart des écosystèmes de notre planète mais représentent également une menace pour la santé humaine. Leur éradication est un véritable défi pour la microbiologie moderne du fait de leur résistance élevée aux antibiotiques. Providencia stuartii est une bactérie Gram-négative connue pour sa forte capacité à former des biofilms dans le tractus urinaire humain, qui est responsable pour environ 10% des infections nosocomiales urinaires chroniques. Nous avons montré que cette souche bactérienne exploite un moyen de socialisation supplémentaire préalable à l’adhésion des cellules aux surfaces et la sécrétion d’une matrice extracellulaire, les communautés flottantes. Les deux porines de P. stuartii, Omp-Pst1 et Omp-Pst2, soutiennent la formation des communautés flottantes en s’auto-associant à travers leurs boucles extracellulaires pour former des dimères de trimères (DOTs) intercellulaires. La formation des DOTs, rivetant les cellules adjacentes entre elles, est médiée par des forces électrostatiques et des interactions de type steric zipper.Les deux grands objectifs de la thèse ont été i) de caractériser les impacts environnementaux sur l’établissement et la survie des deux types de communautés formés par P. stuartii, et ii) d’empêcher la socialisation bactérienne par inhibition des DOTs de porines. Nos résultats ont montrés que des peptides mimant les résidus impliqués dans les interactions de type stérique zipper des DOTs de porines, et couplés à de la coumarine, sont prometteurs pour diagnostiquer les infections à P. stuartii. De plus, nous avons mis en avant qu’une combinaison d’antibiotiques avec certains de ces peptides est une nouvelle approche thérapeutique envisageable pour lutter contre les infections de P. stuartii. Nos résultats montrent aussi que les futurs traitements devraient être évalués sur les communautés flottantes et les biofilms adhérents, dans des conditions imitant les voies urinaires, afin d’être efficaces et potentiellement éradiquer P. stuartii. / Bacterial biofilms are multicellular communities adherent to surfaces and surrounded by an extracellular matrix. They are crucial for maintaining most of our planet’s ecosystems, but also a threat to human health. Biofilm eradication is one of the greatest challenges of modern microbiology due to their high resistance to antibiotics. In this PhD, we focused on Providencia stuartii, a Gram-negative pathogen that forms biofilms in the human urinary tract and is responsible for about 10% of hospital-acquired urinary tract infections. P. stuartii exploits an additional means of socialization, forming floating communities of cells (FCCs), that later sediment and adhere onto surfaces yielding surface-attached biofilms (SABs). The two porins of P. stuartii, Omp-Pst1 and Omp-Pst2, are involved in FCC formation by self-association into intercellular dimers of trimers (DOTs). The main driving force behind DOT formation is electrostatic attraction, yet the DOT structure is locked-in by steric zipper interactions between facing extracellular loops.The two main objectives of this PhD were (i) to characterize the environmental impacts on the establishment and survival of the two type of socialized communities formed by P. stuartii, and (ii) to inhibit bacterial socialization by targeting porin DOTs. Our results reveal that peptides featuring residues involved in the steric zipper interaction of DOTs, and coupled with coumarin, are promising lead compound to diagnose P. stuartii infections. In addition, we tested combinations of antibiotics with some of these peptides and results suggest that is was a new therapeutic approach that can be envisaged to fight against P. stuartii infections. Future treatments should be evaluated on FCCs and SABs in conditions mimicking urinary tract, to be efficient and potentially eradicate P. stuartii.

No description available.

Nitrogen removal technologies can help dairy industries meet their nutrient management needs. This thesis investigated two separate treatment technologies for total ammonia nitrogen (TAN) removal: algae raceway ponds and aerated biofilm reactors. Six 1000- liter algae raceway ponds and four 1000-liter tote tanks, each equipped with 10 sheets of nonwoven geotextile (i.e., thermally bonded or needle-punched) biofilm substrate, were used to treat the effluent from a flush dairy in central coastal California (TAN = 251 mg/L, cBOD5 = 204 mg/L). For the algae raceway ponds (TAN loading rate = 7 - 35 g/m³-day among 7-, 10- and 14-day hydraulic residence times (HRT)), first-order removal rate constants (k) were ~0.2 day⁻¹ in the summer and 0.1 - 0.2 day⁻¹ in the winter. Removal rate constants had no correlations (R² < 0.1) with water temperature, weak to moderate (for 7-day ponds, R² = 0.55) correlations with insolation and weak to no correlations with biomass (i.e. volatile solids) concentration. During the winter, low insolation likely inhibited algal photosynthesis and biological TAN treatment. Ponds with 7-day HRT had distinct absence of nitrate and nitrite compared to 10- and 14-day ponds. Net productivities were ~20 g/m²-day in summer and 9 – 11 g/m²-day in winter; gross productivities were 120 – 160 g/m²-day in summer and 77 – 150 g/m²-day in winter. Productivities had no correlations (R² < 0.1) with water temperature and weak to moderate correlations (for 14-day ponds, net productivity R² = 0.56, gross productivity R² = 0.83) with insolation. Analysis of organic compounds in pond effluent showed dissolved volatile solids (~2300 mg/L) were mostly non-biodegradable (~98% of soluble oxygen demand). Dissolved organic nitrogen concentrations in the pond effluent were ~35 mg/L. For the aerated biofilm reactors, tanks with needle-punched geotextiles had greater first- order TAN removal rate constants (0.69 day⁻¹) than tanks with thermally bonded geotextiles (0.23 day⁻¹) while operating in batch mode. Needle-punched geotextile reactor also accumulated sludge faster and had higher attached to water column biomass (i.e. volatile solids) ratios (~0.08 g VS/g VS) than thermally bonded geotextile reactor (~0.04 g VS/g VS). Among the four tanks, mass of attached biomass was 150 – 340 g per tank while mass of biomass in the water column was 3290 – 5430 g per tank. Comparing the two treatment technologies, aerated biofilm reactors (removal = 64 – 77%, k = 0.2 – 0.3 day⁻¹, removal rate = 36 – 43 g-N/m²-day, 16 – 19 g-N/m³-day) had more removal and faster removal rates per square meter of land footprint compared to the algae raceway ponds (removal = 38 – 77%, k = 0.1 – 0.2 day⁻¹, removal rate = 4 – 5 g- N/m²-day, 13 – 17 g-N/m³-day), likely due to direct application of aerators in the reactors.

No description available.

Due to a number of factors, the biodiesel industry in the United States is surging in growth. Traditionally, oil seed crops such as soybean are used as the feedstock to create biodiesel. However, the crop production can no longer safely keep up with the demand for the growing biodiesel industry. Using algae as a feedstock has been considered for a number of years, but it has always had limitations. These limitations were mainly due to the production methods used to grow and harvest the algae, rather than the reaction methods of creating the biodiesel, which are the same as when using traditional crops. Algae is a promising alternative to other crops for a number of reasons: it can be grown on non arable land, is not a food crop, and produces much more oil than other crops. In this project, we propose a novel attached growth method to produce the algae while recycling dairy farm wastewater using the microalga Chlorella sp. The first part of the study provided a feasibility study as the attachment of the alga onto the supporting substrate as well as determining the pretreatment options necessary for the alga to grow on wastewater. The results showed that wastewater filtered through cheesecloth to remove large particles was feasible for production of Chlorella sp, with pure wastewater producing the highest biomass yield. Most importantly, the attached culture system largely exceeded suspended culture systems as a potentially feasible and practical method to produce microalgae. The algae grew quickly and were able to produce more than 3.2 g/m2-day with lipid contents of about 9% dry weight, while treating dairy farm wastewater and removing upwards of 90% of the total phosphorus and 79% of the nitrogen contained within the wastewater. Once the "proof-of-concept" work was completed, we investigated the effects of repeat harvests and intervals on the biomass and lipid production of the microalgae. The alga, once established, was harvested every 6, 10, or 15 days, with the remaining algae on the substrate material functioning as inoculums for repeated growth. Using this method, a single alga colony produced biomass and lipids for well over six months time in a laboratory setting. The second part of this study investigated another aspect of biodiesel production from algae. Rather than focus solely on biomass production, we looked into biodiesel creation methods as well. Biodiesel is created through a chemical reaction known as transesterification, alcoholysis, or commonly, methylation, when methanol is the alcohol used. There are several different transesterification methods. By simplifying the reaction conditions and examining the effects in terms of maximum fatty acid methyl esters (FAME) produced, we were able to determine that a direct transesterification with chloroform solvent was more effective than the traditional extraction-transesterification method first popularized by Bligh & Dyer in 1959 and widely used. This synergistic research helps to create a more complete picture of where algal biodiesel research and development is going in the future. / Master of Science