<p>This is a project about The Water Treatment System at Djupdalen. The leakage water comes to the Water Treatment System from a deposition plant through the land. The leakage water is characterized by a high concentration of nitrogen and the system is based on biological removing of the nitrogen in the water, by nitrifying and denitrifying bacteria. Four different problems are found in the system: 1. High level of nitrogen concentration in the outgoing water of the system. It should be due to the lack of phosphate in the water, that do not let the bacteria to grow. 2. Low temperature during the most part of the year. Nitrifying and denitrifying bacteria are temperature-dependent, that are very slow at low temperatures. 3. High oxygen concentration in one of the anoxic pond, where the denitrification process take place. This oxygen concentration is too high for denitrifying bacteria to work. 4. The nitrification and denitrification bacteria need to be “old” to work efficiently. They need a surface to attach, because if not they flow with the water and they leave the system. And four possible solutions for the system are presented: 1. Phosphate should be added to the system to let bacteria growth. 2. Store the water at a store pond during the winter months and transport it to the system when the temperature is optimum for the bacteria to work. 3. Add carbon matter to improve the carbon oxidation and to low down the oxygen levels at the anoxic ponds. 4. Two options are presented to improve the system, the first one is based on the construction of a dark wavy bottom in the channel system, which will give a surface for bacteria to attaché, it will produce oxygenation in the water, and it will also improve the water temperature; and the second one is based on the addition of panels made of black material, which will give to bacteria a surface to attach, and improve the water temperature.</p>

This project explored the feasibility of using fungi in a constructed wetland for the treatment of pulp mill effluent. The effluent is high in dissolved lignins (some of which are chlorinated), which have proven very difficult to degrade biologically. Mindful of work done with the (terrestrial) white rot fungi, especially Phanerochaete chtysosporium, the question is asked, Is there a fungus which can tolerate submerged conditions while degrading a significant amount of dissolved lignins? Two fungal species with lignin-degrading capability were isolated from submerged films in a log pond. These fungi have been evaluated for decolorization potential under different environmental conditions. Results of laboratory experiments show that one of these fungi, identified as Acremonium sp., was capable of 44% decolorization of pulp mill effluent under sterile, submerged, room temperature conditions. The fungal decolorization was evaluated both in floating cultures and as a film inoculated on wood chips. In addition, bench-scale examination of the potential of this fungus to decolorize pulp mill effluent in non-sterile conditions was completed. / Graduation date: 1994

Oak savannas are among the most imperiled ecosystems in the United States as a result of habitat degradation and consequently, associated vegetation and wildlife communities have also declined. I evaluated savanna restoration strategies on twelve case studies in Tennessee and Kentucky. These case studies represented a broad range of disturbances and the most advanced savanna restoration sites within the region. I evaluated vegetation and breeding bird responses to landscape and overstory conditions across sites through a meta-analysis. Total grass and forb cover were influenced by overstory metrics but not by topography (P >0.05). Oak regeneration density was influenced by canopy cover, while oak competitor regeneration density was influenced by percent slope and sapling density (P <0.05). With respect to breeding birds, I found forest species persisted within case studies despite substantial disturbance; shrub/scrub birds were common on disturbed sites. Only three obligate grassland bird species, Tyrannus tyrannus, Aimophila aestivalis, Spiza americana, were observed on my sites. Relative abundance of Passerina cyanea was positively related to the groundlayer development; whereas that of Melanerpes erythrocephalus was positively related to basal area of dead trees (P <0.05). Based on my results, canopy reduction and growing-season burns may both be critical for the restoration of savannas within the region. Drum-chopping is a tool that may expedite oak savanna restoration through improved woody competition control, however, its effectiveness has not been investigated. Therefore, I evaluated drum-chopping effects on vegetative structure at Catoosa Wildlife Management Area, Tennessee, during 2008 and 2009 using two adjacent sites with similar fire and overstory removal histories. One site was subjected to drum-chopping in September of 2007, while an adjacent site (control) was not chopped. Drum-chopping reduced grass and forb cover, and oak seedling density, but increased bare ground and density of vines and shrubs versus the control (P <0.05). Except for bare ground, differences were no longer apparent in the second year. Based on my results, drum chopping may reduce midstory vegetation too thick to be effectively controlled by fire, but otherwise has limited utility as a restoration tool. Although wildlife managers have tried to restore savannas using prescribed fire and overstory canopy removal, use of other tools may be warranted. One such method is drum-chopping, which has been used elsewhere to reduce woody competition. However, the effectiveness of this method in restoring oak savannas has not been evaluated. Therefore, I evaluated drum-chopping effects on plant composition at Catoosa Wildlife Management Area on the Cumberland Plateau in Tennessee. Two adjacent sites with similar fire and overstory removal histories were selected for this study. One of these sites was subjected to drum-chopping (CHOP) in September of 2007, the adjacent site was not chopped (NOCHOP). Grass cover differed by treatment (P <0.01) and year*treatment (P = 0.03). Forb cover differed by treatment (P <0.01) and legume cover differed by year (P <0.01), treatment (P <0.01), and year*treatment (P = 0.01). Exposed bare ground differed by year (P <0.01) and treatment (P <0.01). Exposed leaf litter differed by year (P <0.01). Vines and shrubs (<1.37m tall) differed by treatment (P <0.01). Oak seedling (0-30.48 cm tall) densities differed by treatment (P = 0.05). Based on my results, drum chopping may be a valuable tool where woody encroachment has become too thick for fire to be effective or herbicides are not a viable option, but otherwise has limited utility as a tool for oak savanna restoration.

Objectives were to determine: 1) whether estradiol benzoate (EB) provides a superior alternative to GnRH for synchronizing emergence, growth and maturation of a new follicular wave for fixed timed AI (TAI) in Bos indicus-influenced cattle using CIDR-based protocols, 2) the effect of 48 h calf removal at CIDR removal on the rate of maturational synchrony of the dominant follicle and 3) the effect of varying the magnitude of peak plasma progesterone (P4) concentrations following CIDR insertion on the suppression of FSH and LH secretion in a CIDR-based protocol using EB. In experiment 1, sixty-four Braford (F-1) females were stratified by BCS, parity and days postpartum and assigned randomly to one of four groups in a 2 x 2 factorial arrangement of treatments: 1) Select-Synch + CIDR, 2) Select-Synch + CIDR with 48 h calf removal, 3) E-Synch + CIDR or 4) E-Synch + CIDR with 48 h calf removal. A greater number of cattle in the EB treated group exhibited NFWE compared to the GnRH group, 29 vs 17 cows for EB and GnRH respectively, (P<0.0006). Intervals to NFWE were also greater in EB treated cattle than in GnRH treated cattle, 4.2 vs 2.7 d for EB and GnRH treated cattle respectively, (P<0.0001). Proportions of GnRH- and EB-treated cows ovulating after CIDR removal did not differ. Post-CIDR suckling status did not affect ovulation frequency or interval to ovulation. In experiment 2, eight pubertal (F-1) heifers were used in a Latin Square design with four treatment levels of P4: 1) EB only, 2) EB and new CIDR, 3) EB and new autoclaved CIDR, 4) EB, new autoclaved CIDR and P4 injection at CIDR insertion. Treatments 2 through 4 increased (P < 0.01) mean plasma P4 concentrations compared to treatment 1, with treatment 4 creating the greatest increase in P4 with the longest duration. Suppression of plasma FSH was greatest in group 4 (P<0.08), with mean 60 h concentrations less than in all other groups. Mean concentrations of LH were lesser in group 4 than groups 1 and 2. Frequencies of occurrence of NFWE and ovulation and intervals to NFWE did not differ among treatments. Results indicate that the use of EB and CIDR to synchronize Brahman x Hereford females may provide better synchronization for TAI compared to GnRH and CIDR based protocols.

This dissertation is in the area of Computer-Aided Design (CAD) of digital Integrated Circuits (ICs). Today's digital ICs, such as microprocessors, memories, digital signal processors (DSPs), etc., range from a few thousands to billions of logic gates, flip-flops, and other components, packed in a few millimeters of area. The creation of such highly complex systems would not be possible without the use of CAD tools. CAD tools play the key role in determining the area, speed and power consumption of the resulting circuits. We address several problems related to the logic synthesis step of the CAD flow. First, we investigate properties of double-vertex dominators in directed acyclic graphs. We present an O(n) algorithm for identifying all O(n2) double-vertex dominators of a given vertex, where n is the size of the graph. The key to the algorithm's efficiency is a new data structure for representing double-vertex dominators which has O(n) size and can be efficiently manipulated. This work improves the state of the art in double-vertex dominators identification in terms of both space and time complexity. We also show how dominators can be used for structural decomposition of Boolean functions represented by circuit graphs. Next, we present a depth-optimal technology mapping algorithm for look-up table (LUT) based Field Programmable Gate Arrays. This algorithm is two orders of magnitude faster than previous technology mapping algorithms while achieving solution with a smaller number of LUTs. We also consider level-limited decomposition of Boolean functions which is of particular interest for applications which require circuit representations of a limited depth, such as control logic of microprocessors. We present an efficient algorithm for computing the decomposition of type f = g * h + r, where f, g, h and r are Boolean functions. Another contribution of the dissertation is an algorithm for identifying and removing redundancy in combinational circuits. This algorithm provides a quick partial solution which might be more suitable than exact ATPG and SAT-based approaches for redundancy removal runs at the intermediate steps of the CAD flow. It is embedded into the internal logic synthesis tool of IBM. Other contributions of the dissertation are a proof that, for some Reduced Ordered Binary Decision Diagrams, none of the bound-set preserving orderings is best, a proof of the existence of a perfect input assignment which guarantees that two non-equivalent Boolean functions hash to two different values, and a set of efficient algorithms for the analysis of random Boolean networks. / QC 20100914

In Sweden more than 400 000 private households have not yet sufficient wastewater purification. These effluent is considered as an increasing problem and many onsite purification methods have been studied. In this investigation, the method of reactive bed filters have been tested by column and batch experiments. Five different kinds of filter materials with reactive surfaces have been studied concerning their capacity to absorb ammonium and phosphorus from wastewater. The materials that were examined are Filtra N, wollastonite Filtra P, blast furnace slag and Polonite®. The first two materials were examined for their capacity to remove ammonium, and the others for their phosphorus removal capacity. Ten columns were used, two for each material. A synthetic solution with the ammonium and phosphate concentration similar to that of domestic wastewater (NH4-N 30 mg/l; PO4-P 5 mg/l) were pumped to the columns under two flow regimes. Five columns were continuously saturated with solution and the other five columns were saturated under three one hour periods a day The solution was pumped three times a day to the columns at a volume equal to the pore volume of each material. The objective of the batch experiment was to find out how variations in pH-value and concentration of the nutrients influenced the sorption capacity of the materials. The result was then used for modelling in the computer program Visual Minteq to determine the probability of precipitation of known compounds. Results from the column experiment showed that sorption of phosphorus in both saturated columns and intermittently saturated columns were 96 % or more for blast furnace slag, Filtra P and Polonite®. Filtra N showed the best ammonium sorption with 92 %. Sorption of ammonium was much better in periodically saturated columns for the material wollastonite. The wollastonite used in this experiment showed a higher phosphorus sorption capacity than expected. A possible explanation could be that the easy weathering of Ca-silicate compounds favoured the sorption of phosphorus. Results from Visual Minteq modelling showed that the probability of calcite formation in Filtra P and Polonite® are very likely. The two materials had high pH-values and the calcite was most likely formed at values of pH &gt; 10. Hydroxyapatite is the most common precipitation when phosphorus sorption occurs and is suggested to be formed in wollastonite. / Mer än hälften av Sveriges enskilda avlopp bedöms inte uppfylla kraven i miljöbalken på längre gående rening än slamavskiljning. Dessa står för en betydande del av fosfor- och kväveutsläppen till hav, sjöar och vattendrag. Åtskilliga systemlösningar utreds, men i denna rapport har filter med fosfor- och kvävesorberande förmågor testats eller s.k. reaktiva filter. Mineraliska filter som ingått i studien är Filtra N, wollastonit, Filtra P, hyttsand och Polonite®. De två första filtren studerades speciellt på deras förmåga att avskilja ammonium och de tre övriga främst på deras fosforavskiljnings förmåga. Kolonnförsök utfördes med tio kolonner där fem belastades med mättat flöde och de övriga med intermittent mättat flöde. Kolonnuppsättningen var två kolonner per filtermaterial med vardera olika flödesförhållanden. Belastningen på kolonnerna sattes till betydligt högre än traditionell infiltration/markbädd. Ett artificiellt avloppsvatten användes och tillreddes med en koncentration av kväve (NH4-N) på 30 mg/l och fosforkoncentration (PO4-P) på 5 mg/l. De valda koncentrationerna efterliknar ett vanligt hushållsspillvatten. Skakförsök utfördes för att undersöka sorptionsförmågan hos de olika mineraliska filtren där vikten låg på hur koncentrationen av näringsämnena och pH påverkar sorptionen. Resultaten från skakförsöken utvärderades med jämviktsmodellen Visual Minteq. Sannolikheten att kända utfällningar bildas studerades. Resultaten från kolonnförsöken visade att hyttsand, Filtra P och Polonite® gav bäst fosforavskiljning med över 96 % för båda flödesregimerna. Filtra N var den bästa ammoniumavskiljaren med över 92 %. Wollastonit hade en bättre avskiljning med intermittent mättat flöde med 65 % jämfört med 11 % för mättat flöde. En intressant iakttagelse var att wollastonit hade en bättre fosforavskiljning än ammoniumavskiljning med ca 60 % för båda flödena. Det kan bero på att filtret innehåller lättvittrade Ca-silikatföreningar som ökar fosfatavskiljningen. Skakförsöken resulterade i att för Filtra P, hyttsand och Polonite® sorberades all tillsatt fosfat. Filtra N visade samma resultat som i kolonnförsöken med över 92 % sorption. Endast fosfat sorberades vid försök med tillsättning av både fosfat och ammonium till hyttsand och wollastonit. Vid modellering i Visual Minteq finns det en viss sannolikhet att kalcit bildats i Filtra P och Polonite® p g a deras höga pH, kalcit fälls ut vid pH &gt; 10. Hydroxyapatit som är den vanligaste utfällningen av kalciumfosfat vid avskiljning av fosfor bildades mycket troligt i wollastonit.

The polluted agricultural wastewater, after reaching marine recipients, can cause eutrophication. This problem can be tackled and mitigated by using constructed wetlands as water treatment systems. The fact that constructed wetlands work through long periods of time has led many scientists to evaluate how long they can still treat their influents effectively. The development and growth of vegetation and the accumulation of nutrients on the soils in a wetland are expected to occur. These processes change the wetland efficiency to remove pollutants. In this study, a set of wetlands constructed to treat agricultural wastewater were analyzed in different periods to assess if there is a difference in removal efficiency of nitrogen and phosphorus. This assessment was performed by analyzing the retention rate, k and k20 values, which are variables that quantify the nutrients removal, in different periods of each employed wetland. Some of the observations demonstrated differences when comparing different periods of the wetlands. The nitrogen removal presented better performance in one of the employed wetlands when this was older. Another employed wetland has not shown a clear difference between different periods. In the wetlands with high vegetation densities, the nitrogen removal was more stable over consecutive years. The occurrence of oscillations in nitrogen removal was observed more often in the wetlands with the highest vegetation densities over consecutive years. The phosphorus removal presented no clear differences between different periods. The results suggest that the removal of nitrogen improves after wetland creation due to the growth of vegetation. In addition, they suggest that wetlands with high vegetation densities tend to oscillate the nitrogen removal more or less often according to the density of the vegetation due to the balance between denitrification and decomposition. Further, the results suggest that the removal of phosphorus remains unchanged over longer periods than the periods considered in this study (four to six years) due to the deposition of organic matter on the soils.

Each new generation of integrated circuits and other nano-structured devices is produced at ever decreasing length scales. The extension of conventional liquid-phase processes for the manufacturing of these devices is uncertain. This work investigates the ability of liquids to wet nanoscale features. A model for wetting time is derived that may be used to identify those geometries for which wetting is critical. Conditions under which wetting time is significant may result in low yield and poor uniformity, and may require alternate-phase processing. Furthermore, the dependence of wetting time on the properties of the fluid are quantified so that fluids may be designed to have optimal properties and thus optimal performance for wetting. The resulting model can be used as a tool to predict future processing requirements, and when necessary, to design novel processes implementing alternative phase fluids such as gas-expanded liquids (GXLs). This study also quantitatively predicts specific effects associated with modified transport properties for dissolution and transport in nanoscale features. The use of GXLs is a particularly promising alternative to conventional liquid-phase processes. GXLs have superior mass transport properties relative to liquids, but can maintain the solvent strength necessary for IC process steps such as post-etch residue removal and photoresist stripping. In addition, the environmental benefits associated with CO2-based processes can be substantial. Conceptual demonstration of the use of carbon dioxide (CO2)-expanded liquids for photoresist and residue removal has been performed. GXLs containing up to 75% CO2 are equally as effective as the pure solvents for removal of PHOST-based films. These experiments indicate that GXLs have potential applications in photoresist stripping and post-etch residue removal, in which cost savings due to reduced solvent use can be substantial. The removal of films with GXLs has been evaluated primarily with x-ray photoelectron spectroscopy (XPS). Additionally, an in situ optical technique has been developed for film and GXL diagnostics. This technique has been used to evaluate the response of PHOST-based thin films to GXLs and to monitor density changes of liquids upon gas expansion.

No description available.

A fixture is a critical link in a machining system. The majority of prior work treats the fixture-workpiece system as quasi-static and ignores the system dynamics. In addition, material removal effect (MRE) on fixture-workpiece dynamics is generally ignored. The primary goal of this thesis is to develop a model-based framework for analysis and synthesis of the fixturing dynamic stability of a machining fixture-workpiece system accounting for the MRE. Five major accomplishments of this thesis are summarized as follows: First, a systematic procedure for analysis of fixturing dynamic stability of an arbitrarily configured machining fixture-workpiece system is developed. Second, models and approaches developed in this work are experimentally validated. It is found that consideration of dynamics and characterization of system dynamic properties are crucial for an accurate analysis. Third, an in-depth investigation of the MRE on fixture-workpiece dynamics is performed. The results show that material removal can significantly change the system characteristics and behavior and approaches developed are capable of capturing the change. Fourth, roles of important fixture design and machining process parameters in affecting fixturing dynamic stability are studied and understood via a parameter effect analysis. Additionally, fixturing dynamic stability is found to be sensitive to the parameter imprecision. Finally, a generic approach for determination of minimum clamping forces that ensure fixturing dynamic stability is developed. Because of MRE, dynamic clamping is found to be an option to achieve the best possible system performance. Models and approaches developed in this thesis are generic and can be used as simulation tools in fixture design. Insights obtained from this research advance the knowledge base of machining fixtures and provide general fixture design guidelines.