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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

A colloidal nanoparticle form of indium tin oxide: system development and characterization

Gilstrap, Richard Allen, Jr. 06 April 2009 (has links)
A logical progression from the maturing field of colloidal semiconductor quantum dots to the emerging subclass of impurity-doped colloidal semiconductor nanoparticles is underway. To this end, the present work describes the formation and analysis of a new form of Tin-doped Indium Oxide (ITO). The form is that of a colloidal dispersion comprised of pure-phase, 4-6 nanometer ITO particles possessing an essentially single crystalline character. This system forms a non-agglomerated, optically clear solution in a variety of non-polar solvents and can remain in this state, at room temperature, for months and potentially, years. ITO is the most widely used member of the exotic materials family known as Transparent Conductive Oxides (TCOs) and is the primary enabling material behind a wide variety of opto-electronic device technologies. Material synthesis was achieved by initiating a series of interrelated nucleophilic substitution reactions that provided sufficient intensity to promote doping efficiencies greater than 90% for a wide range of tin concentrations. The optical clarity of this colloidal system allowed the intrinsic properties of single crystalline ITO particles to be evaluated prior to their use in thin-films or composite structures. Monitoring the temporal progression of n-type degeneracy by its effects on the optical properties of colloidal dispersions shed light on the fundamental issues of particle formation, band filling (Burstein-Moss) dynamics, and the very origin of n-type degeneracy in ITO. Central to these studies was the issue of excess electron character. The two limiting cases of entirely free and entirely confined electron motion were evaluated by application of bulk-like band dispersion analysis and the effective mass approximation, respectively. This provided a means to estimate the number of excess conduction band electrons present within an individual particle boundary. The ability to control and optimize the level of n-type degeneracy within the colloidal ITO nanoparticle form by compositional variation was also demonstrated. A key to the widespread adoption of a new material by industry is an ability to produce multi-gram and perhaps, kilogram quantities with no significant sacrifice in quality. Accordingly, a modified synthesis process was developed to allow for the mass production of high-quality colloidal ITO nanocrystals.
52

Moss-sedumtakets bullerdämpande egenskaper : The noise reduction capability of greenroofs

Jonsson, Mattias January 2009 (has links)
<p></p><p>Syftet med arbetet är att få en förståelse för moss-sedumtakets bullerdämpande egenskaper. Jag kommer även att försöka förutsäga med hjälp av akustikteori vilken utav de två olika uppbyggnadssystemen av moss-sedumtak som ger den bästa bullerdämpande effekten.</p><p>Mätningarna kommer att bestå i att registrera ljudtrycksnivån i rummet, vid varje oktavband i frekvensområdet 125-4000 Hz. Först utan moss-sedummattan och sedan med moss-sedum mattan. Storleken på differensen i ljudnivån ger en bild av i vilket frekvensområde som ljudabsorptionen är effektivast. För att ytterliggare öka förståelsen för hur moss-sedum absorberar ljud så kommer även absorptionsfaktorn att beräknas. Utifrån resultaten kan man se en tydlig bild på hur xeroflor moss-sedum mattan absorberar i frekvenserna 125-4000 Hz. Den har sin bästa absorption i området 500-4000 Hz och i detta område så är det runt 1000 Hz som den absorberar effektivast.</p><p> </p><p>Om vi tittar på de två olika systemen som Veg Tech använder för att bygga upp ett sedumtak på så sker dämpningen i XMS 0-4 med hjälp av luftspalten och i system XMS 2-27 i VT-filten. Men i detta fall så är luftspalten endast 25 mm så en märkbar ökad dämpning är svårt att föreställa sig. VT-filten som används i XMS 2-27 har öppna celler och kan liknas vid mineralull, som är en bra absorbent. Min slutsats är att 10 mm VT-filt ger bättre dämpning än en luftspalt på 25 mm.</p><p> </p>
53

A polysaccharide extracted from sphagnum moss as antifungal agent in archaeological conservation

ZAITSEVA, NINA 14 January 2010 (has links)
On the basis of the well-known preservative properties of Sphagnum moss, a potential opportunity to use moss polysaccharides (Sphagnan) in art conservation was tested. Polysaccharides were extracted from the moss (S. palustre spp.) in the amount of 4.1% of the Sphagnum plant dry weight. All lignocelluloses were removed from this extract as a result of the treatment of the moss cellulose with sodium chlorite. The extracted polysaccharide possessed a strong acidic reaction (pH 2.8) and was soluble in water and organic solvents. The extract was tested on laboratory bacterial cultures by the disk-diffusion method. The antibacterial effect was demonstrated for E. coli and P. aeruginosa (both gram-negative) while Staphylococcus aurelus (gram-positive) was shown to be insensitive to Sphagnum polysaccharides. The antifungal effect of Sphagnum extract was tested by the disk-diffusion method on the spores of seventeen fungal species. These fungi were isolated from ethnographic museum objects and from archaeological objects excavated in the Arctic. Twelve of these isolates appeared susceptible to the extract. The inhibiting effect of the extract was also tested by the modified broth-dilution method on the most typical isolate (Aspergillus spp.). In this experiment, in one ml of the nutritious broth, 40µl of 3% solution of polysaccharides in water killed 10,000 fungal spores in 6 hours. The inhibiting effect was not connected to the acidity or osmotic effect of Sphagnum polysaccharides. As an example of the application of Sphagnum polysaccharides in art conservation, they were added as preservative agents to conservation waxes. After three weeks of exposure of microcrystalline wax to test fungi (Aspergillus spp.), 44% of wax was consumed. When, however, ~ 0.1% (w/w) of Sphagnum extract was mixed with wax, the weight loss of wax was only 4% in the same time interval. On the basis of this study it was concluded that Sphagnum moss and Sphagnum products can be recommended for use in art conservation as antifungal agents. / Thesis (Master, Art Conservation) -- Queen's University, 2010-01-14 15:55:23.779
54

INTERACTION OF IRRADIANCE AND STOCKING DENSITY ON NUTRIENT UPTAKE BY RED MACROALGAE. IMPLICATIONS FOR BIOREMEDIATION OF FISH FARM EFFLUENTS

Manriquez-Hernandez, Juan A. 15 August 2013 (has links)
In land-based integrated aquaculture of marine finfish and macroalgae, rearing space is a large expense. Increasing algal stocking density can increase efficiency, but this may require greater irradiance because of self-shading. To determine the irradiance needed, experiments were conducted in one-litre flasks with enriched seawater under natural and artificial illumination. Under natural illumination, a Daily Photon Dose of 17 mol m-2 d-1 at 10 and 14 ºC, Palmaria palmata cultured at 10 g L-1 grew 100 % faster and absorbed 20 % more nutrients than Chondrus crispus. However, Atlantic halibut farm effluent can reach up to 19 ºC in summer, too high for P. palmata. Under artificial illumination, C. crispus performed better than under natural illumination. Light saturation curves indicated nutrient uptake by C. crispus at 10 g L-1 and 10 ºC was highest at 23 mol m-2 d-1 irradiance, equivalent to 400 µmol m-2 s-1 for 16 hours
55

EFFECTS OF NITROGEN DEPOSITION ON BOREAL BOGS: A THREE YEAR NITROGEN FERTILIZATION AND TRACER EXPERIMENT

Xu, Bin 01 August 2011 (has links)
Boreal peatlands play important roles in global C and nutrient cycling. Oligotrophic bogs are naturally nitrogen (N) limited, receiving nutrients only via atmospheric deposition. Increased nutrient deposition, particularly N will almost certainly change the microbiology, biogeochemistry, and C and nutrient balances in bogs. Both primary production and decomposition can be affected, but the net effects of N fertilization are complex and unclear. A three-year N fertilization experiment with 15N double labeled 15NH415NO3 as a tracer was designed to study the effects of increasing N deposition on various N pools (including microbial communities, moss, roots, litter, and aboveground vascular plants) and how these N pools process and retain applied N in four ombrogenous bogs in northern Alberta, Canada. Linear growth of Sphagnum mosses was highly variable. However, both capitulum and stem weight showed increase in weight with N addition, resulting in significant increase of capitulum and stem bulk density with N deposition. Total annual primary production, with both capitulum and stem growth accounted for, doubled from low N deposition plots to high N deposition plots. Microbial biomass N measured by chloroform fumigation-extraction only showed a decrease with N deposition in the first year of the experiment. Fungal biomass declined with N deposition as nutrients are readily available under high N loads, perhaps eliminating the need for help from symbiotic fungi for nutrient uptake. The growth of Sphagnum mosses and microbial communities may have been influenced by drier and warmer growing period during 2005 to 2007. These abnormal climatic events could have masked the effects of N deposition on surface Sphagnum moss and microbial communities. This 15N tracer experiment revealed high retention rates of 15N by moss layers as expected. However, retention efficiency of moss layers declined over time and with increasing N deposition, indicating a leakier system as N deposition exceeds the critical load of Sphagnum moss. Aboveground vascular plants overall benefited from N deposition, but different species responded differently based on the root morphology, rooting depths, and the mycorrhizae associations.
56

User Support in MOSS 2007

Hällholm, Jon January 2009 (has links)
The purpose of this report is to present the findings from the thesis work performed at Qurius Sweden (former Ibitec). The goal was to evaluate how usable Microsoft Office SharePoint Server 2007 (MOSS 2007) was in general and how usable two portal solutions created for MOSS 2007 were in particular. The goal also consisted ofevaluating how SharePoint could be improved in terms of usability and accessibility. The last part of the thesis work was to create a dynamic help tool, from where application specific help could be created.The usability was evaluated with a variant of usability engineering. Not all of the original method could be used because the products analyzed were already finished. The results from the analysis show that MOSS 2007 is quite usable, especially when it comes to document handling. It is also possible to create web pages and sites with ease. MOSS 2007 lacks in usability when it comes to presenting information to the user regarding what is going on in the system and. The system can also be quite complex and much to grasp for an end user. Solutions created in MOSS 2007 follows closely the usability of MOSS 2007 but they can be made very usable if only certain aspects are considered. Example of improvements could be the placement of the help system, clearer error messages and an overlook of managing user rights.The dynamic help tool was created in the programming language C# and based on the .NET platform. The implementation is a so-called Web Part that can easily be inserted on a page in MOSS 2007. The help tool uses the built in help system in MOSS 2007 for editing present help files and for adding new files to it. The help tool has a very minimalistic design and the focus was on the tasks it should be performing rather than a nice-looking interface. To ensure usability for the help tool, future work should be done, testing the product with real users and apply other usability methods to improve the help tool. As of now, no usability methods have been used while developing the help tool, nor have any tests with real users been performed. This is to be considered as future work.As a conclusion, both MOSS 2007 and the solutions created for it can be said to have a certain degree of usability shown from the evaluations. Improvements can be done, and should be, in order to increase the users’ experience. With the help tool, it is now possible to create solution specific help for a project intended for MOSS 2007.
57

Jämförelse av aggregeringswebbdelar i MOSS 2007 / Comparison of aggregationwebparts in MOSS 2007

Aghili, Mohammed January 2010 (has links)
En typisk funktion på startsidan till många webbportaler är den webbdel som presenterar exempelvis desenaste blogginläggen, nyheterna eller händelserna som har lagts till på webbplatsen. Dessa funktioner ärkända som aggreggeringswebbdelar. Eftersom startsidan är den sida som besöks mest jämfört med alla andrawebbsidor i portalen innebär det i sin tur att denna funktion utnyttjas väldigt ofta.Detta arbete syftar till att finna ett antal olika metoder som kan användas för att uppnå denna funktion ochatt ta reda på hur väl dessa webbdelar presterar.Denna rapport presenterar både de olika metoder som fanns och resultaten på en systematisk testning avdessa. Resultaten av testerna presenteras på ett överskådligt sätt.Slutligen dras slutsatser angående resultaten. Resultaten förespråkar inte en specifik metod, den metod somlämpar sig bäst för varje enskild sammanhang avgörs till största del av andra faktorer såsom frekvens avbesökare eller ändringar på innehållet som metoden söker igenom.
58

Hodnocení CPM aplikací - analytických portálů / Evaluation of CPM applications - analytical portals

Tománek, Jiří January 2010 (has links)
This thesis is concerned with evaluation CPM applications -- Analytical Portals. Based on reading up the evaluation criteria from another authors in third chapter, are chosen own criteria for evaluation of application Microsoft Office SharePoint Server 2007, where are dashboards and reports created. The thesis consists of two general sections, theoretical and practical. The theoretical section describes division of CPM applications from particular vendors of software. In second chapter are explained the most important features of CPM applications and their submission into software portfolio particular vendors, which is the first target of this thesis. In the practical section are worked up the data of fictive company named Matastav into form, which is needed for creating dashboards and reports. After that in fourth chapter, are created dashboards and reports by software MOSS 2007. Here is explanation of the creation and of course the required hardware and software installation. The software and created dashboards and reports are evaluated in fifth chapter with own chosen criteria. That is the second target of this thesis.
59

Lipidomic Analysis of Various Developmental Stages of Physcomitrium patens

Gautam, Deepshila 01 December 2021 (has links)
Lipids maintain fluidity of the cell membrane during the lifetime of all organisms. The moss Physcomitrium patens, an early land plant, enters reproductive phase under cold (15°C) conditions relative to its gametophytes (22°C). Thus, we hypothesized that their lipid content and composition would be distinct. Using ESI-MS/MS, we showed that the content and acyl composition of 11 lipid classes varied during development. Galactolipids were abundant in gametophytes but insignificant in sporophytes; among phospholipids, phosphatidylcholine was predominant in both phases. Although, sporophytes contained around five-fold less lipids than the gametophyte, their phosphatidic acid content, which accumulates during stress, was 18-fold higher. Furthermore, comparative analyses of lipidomes revealed that the 38C and 40C acyl species are abundant in the moss and mouse, which are mostly absent in vascular plants. The occurrence of long-chain, highly unsaturated lipids perhaps contribute to membrane stability that was necessary for the evolution of early land plants.
60

Studium bioakumulace vybraných kovů vodním mechorostem Fontinalis antipyretica / Study of metals bioaccumulation by the aquatic moss Fontinalis antipyretica

Jaskowiecová, Lenka January 2008 (has links)
This diploma thesis is focused on determination of bioavailable cadmium in natural waters. Thesis is devided to two parts-laboratory study in model solution and experiments in real surface water system. During the laboratory experiments the accumulation and release constants of cadmium by aquatic moss Fontinalis antipyretica were determined. In Morava river experiment this aquatic moss was used to determine bioavailable fraction of cadmium and the moss bag technique were compared with another methods for phytotoxic metals determination.

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