Dissertations / Theses: 'Sources of ash'

1

Watson, Simon A. G. (Simon Andrew Glean). "Lubricant-derived ash : in-engine sources and opportunities for reduction." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61614.

Full text

Abstract:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (p. 220-228). Diesel particulate filters (DPF) are an effective means for meeting increasingly stringent emissions regulations that limit particulate matter. Over time, ash primarily derived from metallic additives in the engine oil accumulates in DPFs. Lubricant-derived ash increases pressure drop and reduces fuel economy. After long time periods, the accumulation of ash may lead to irreversible plugging in DPFs, which necessitates periodic filter removal and cleaning. This thesis examines the sources for lubricant-derived ash in engines and explores potential opportunities to reduce ash emissions. The research studies changes in lubricant composition in the engine via advanced in-situ diagnostics and computer modeling of species transport in the power cylinder. These changes are directly related to ash emissions and the effectiveness of the lubricant in protecting engine components. In the first part of this thesis, sampling techniques are employed to determine the composition of the lubricant in critical locations in the engine system, where oil is lost by liquid oil consumption and vaporization. The first practical in-situ FTIR measurements of lubricant composition at the piston and liner interface are obtained with a novel diagnostics system employing Attenuated Total Reflection (ATR) spectroscopy. This information is used to create a mass balance for ash-related elements and a framework for modeling the distribution of ash-related species in the engine. In the second part of this thesis, a novel approach to condition the lubricant at a fixed station in the oil circuit is explored as a potential means to reduce ash emissions. This study examines the performance of an innovative oil filter that releases no additives into the lubricant, yet enhances the acid control function typically performed by detergent and dispersant additives. The filter has the potential to be used as a replacement for detergent additives in a lubricant formulation, or enhance additive effectiveness there-by allowing in an increase in oil drain interval. This research will assist in the development of new formulations for diesel lubricants that minimize detrimental effects on DPFs, while providing adequate protection to engine components. by Simon A.G. Watson. Ph.D.

APA, Harvard, Vancouver, ISO, and other styles

2

Ndlovu, Hendry. "Ash from homestead fireplaces and wood as possible sources of minerals for livestock." Diss., Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-06172008135050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Adams, Zachry Clay Adams James F. "Comparison of broiler litter, broiler litter ash with reagent grade materials as sources of plant nutrients." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Fall/Thesis/ADAMS_ZACHRY_50.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Rezaee, Mohammad. "Development of Strategies to Minimize the Release of Trace Elements from Coal Waste Sources." UKnowledge, 2012. http://uknowledge.uky.edu/mng_etds/6.

Full text

Abstract:

To assess strategies aimed at minimizing the release of trace elements and the impact of disposal of coal waste materials on the environment, two long-term leaching experiments of up to five months duration were performed using waste materials from two plants cleaning high and low sulfur bituminous coal. The tests evaluated the mobility of major trace elements under different disposal scenarios: (i) a static leaching test designed to simulate the quiescent conditions encountered by coal waste material stored under water in a stable impoundment, and (ii) a dynamic test to simulate waste materials exposed to the atmosphere, either in variable wet/dry storage conditions, or in unusual circumstances like those resulting from breaching of an impoundment containment wall. The results indicate that different refuse streams have different leaching characteristics due to difference in their mineralogy and the mobility of most elements is enhanced under highly alkaline or acidic conditions with a few being mobilized under both conditions, suggesting that the minimization of element mobility requires the pH value of the medium to be maintained around neutral. In addition, most of heavy metals were associated with the illite and pyrite minerals. Two strategies of treating coal refuse were evaluated: fly ash mixed with coarse refuse and co-disposal of coarse and fine refuse. Both methods were found to neutralize the pH conditions and thus reduce mobility of the trace elements in static leaching tests whereas the opposite was found from dynamic experiments. The results indicate that such controlled storage under water could retard acid generation and the mobility of trace elements.

APA, Harvard, Vancouver, ISO, and other styles

5

Karlsson, Ulrika. "Environmental levels of thallium : Influence of redox properties and anthropogenic sources." Doctoral thesis, Örebro : Örebro universitetsbibliotek, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-356.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Freret-Lorgeril, Valentin. "Le terme source des panaches de téphras : applications radars aux volcans Etna et Stromboli (Italie)." Thesis, Université Clermont Auvergne‎ (2017-2020), 2018. http://www.theses.fr/2018CLFAC057/document.

Full text

Abstract:

Les panaches volcaniques de téphras constituent un des aléas volcaniques majeurs. Pour prévoir leur dispersion et les zones d'impacts de leurs retombées, des modèles numériques sont utilisés en opérationnel et basés sur des paramètres éruptifs, regroupés sous la notion de terme source, caractérisant l'émission des panaches. L'ensemble du terme source est cependant difficile à mesurer en temps réel. C'est pourquoi les modèles de dispersion sont souvent basés sur des scénarios d'éruptions passées et utilisent des lois empiriques reliant la hauteur des panaches avec les flux massiques à la source. Cependant, les résultats qui découlent de ces modèles sont peu contraints, moyennés sur la durée des éruptions, et souffrent de larges incertitudes. Dans cette optique, les radars Doppler, capables de sonder l'intérieur des colonnes éruptives avec des échelles spatio-temporelles fines, peuvent fournir des contraintes cruciales sur le terme source des panaches en temps réel. Ce travail de thèse traite des applications de radars volcanologiques dédiés, potentiellement transposables aux radars météorologiques communément utilisés, afin de fournir des paramètres éruptifs à la source des panaches de téphras en surveillance opérationnelle mais également pour contraindre la dynamique des colonnes éruptives et les charges internes des panaches et de leurs retombées. Une campagne de mesures au volcan Stromboli a permis de montrer les capacités d'un couplage innovant entre un disdromètre optique (Parsivel2) avec un nouveau radar Doppler à onde millimétrique (Mini-BASTA). Grâce à l'excellente résolution spatio-temporelle de Mini-BASTA (12,5 m et 1 s), des figures intermittentes de sédimentation ont été observées dans les retombées de panaches transitoires dilués. Observées également au disdromètre mesurant la vitesse et la taille des retombées, ces figures ont été reproduites en laboratoire grâce à un modèle analogique. Un modèle conceptuel de formation de thermiques de sédimentation inversés est proposé pour expliquer ces figures et implique que les processus menant à une sédimentation irrégulière typique des panaches soutenus et concentrés peuvent s'appliquer à des panaches dilués, y compris ceux issus d'éruptions Stromboliennes normales en régime transitoire. Ensuite, une caractérisation physique d'un grand nombre de particules de cendres échantillonnées à Stromboli a permis de valider les mesures de tailles et de vitesses terminales de chutes par disdromètre sur le terrain et en laboratoire, justifiant par ailleurs son utilisation opérationnelle. A partir de ces contraintes, une loi reliant les concentrations de cendres avec les facteurs de réflectivité calculés a pu être comparée aux mesures radar in situ. Les concentrations internes modale et maximale des panaches de Stromboli sont respectivement autour de 1 × 10-5 kg m-3 et 7,45 × 10-4 kg m-3, largement supérieures au seuil fixé pour la sécurité aérienne. Les concentrations en cendres des retombées s’étalent entre 1,87 × 10-8 - 2,42 × 10-6 kg m-3 avec un mode vers 4 × 10-7 kg m-3.Finalement, ce travail de thèse montre les applications opérationnelles du radar UHF VOLDORAD 2B dans le cadre de la surveillance de l'activité de l'Etna. Une méthodologie, applicable à tout radar Doppler, a été développée pour obtenir des flux de masse de téphras en temps réel à partir d’un proxy de masse, uniquement basé sur les vitesses d'éjection et puissances mesurées, calibré avec un modèle de colonne tenant compte de l'influence du vent sur les panaches. La gamme de flux trouvée pour 47 paroxysmes entre 2011 et 2015 s’étend de 2.96 × 104 à 3.26 × 106 kg s-1. A partir d’un autre modèle de colonne éruptive, Plume-MoM, les flux radar ont permis de modéliser des hauteurs des panaches de téphras émis lors de quatre paroxysmes de l'Etna cohérentes avec les observations faites en temps réel par imagerie visible et par radar en bande-X. (...) Volcanic tephra plumes are one of the major volcanic hazards. To forecast their dispersion and the impact zones of their fallout, the numerical models used in operational monitoring are based on eruptive parameters, called the source term, characterizing the plume emission. Source term parameters are challenging to measure in real time. This is why dispersion models are often based on past eruptive scenarios and use empirical laws that relate plume heights to source mass fluxes. However, the model outputs are not well constrained, averaged over the eruption duration, and suffer from large uncertainties. In this topic, Doppler radars are capable of probing the interior of eruptive columns and plumes at high space-time resolution and can provide crucial constraints on the source term in real time. This thesis deals with applications in operational monitoring of dedicated volcanological radars, potentially transposable to most common meteorological radars, to provide eruptive parameters at the source of tephra plumes but also to constrain the dynamics and internal mass load of eruptive columns, volcanic plumes and their fallout.A measurement campaign at Stromboli volcano has shown the capabilities of an innovative coupling between an optical disdrometer (Parsivel2) and a new 3-mm wave Doppler radar (Mini-BASTA). Owing to its high spatio-temporal resolution (12.5 m and 1 s), intermittent sedimentation patterns were observed in the fallout of dilute transient plumes typical of normal strombolian activity. These features, also recorded with the disdrometer, measuring the particle settling speeds and sizes, were reproduced in the laboratory using an analog model. A conceptual model for the formation of reversed sedimentation thermals is proposed to explain these features. It implies that processes leading to irregular sedimentation typical of sustained concentrated strong plumes can be applied to dilute weak plumes, including those formed by normal transient Strombolian activity. Then, a physical characterization of a large number of ash particles sampled at Stromboli allowed the validation of particle size and terminal velocity measurements by the disdrometer in the field and in the laboratory, arguing in favor of its operational use. Then, a physical characterization of a large number of ash particles sampled at Stromboli allowed to validate the measurements of size and terminal velocity of falls by disdrometer in the field and in laboratory, justifying also its operational use. From these constraints, a law relating ash concentrations with calculated reflectivity factors was found and compared to in situ radar measurements inside ash plumes and fallout. The modal and maximum internal concentrations of Strombolian plumes are at about 1 × 10-5 kg m-3 and 7.5 × 10-4 kg m-3 respectively, well above the threshold for aviation safety. Ash concentrations in the fallout range from 1.9× 10-8 to 2.4 × 10-6 kg m-3 with a mode at about 4 × 10-7 kg m-3.Finally, this thesis work shows operational applications of the UHF VOLDORAD 2B radar for the monitoring of explosive activity at Etna. A methodology, applicable to any Doppler radar, has been developed to obtain tephra mass eruption rates in real time from a mass proxy, based only on measured ejection velocities and power, and calibrated with an eruptive column model taking crosswinds into account. Tephra mass fluxes found for 47 paroxysms between 2011 and 2015 range from 3 × 104 to over 3 × 106 kg s-1. Then, tephra plumes heights of four Etna paroxysms were simulated using the eruptive column model Plume-MoM from the radar-derived mass eruption rates and were found consistent with real-time observations made by visible imagery and by X-band radar. This last part demonstrates the capabilities of VOLDORAD 2B to provide quantitative input parameters for dispersion models in the case of future Etna paroxysms. (...)

APA, Harvard, Vancouver, ISO, and other styles

7

Ervin, Clara Ray. "Poultry Litter Ash as an Alternative Fertilizer Source for Corn." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/103199.

Full text

Abstract:

Poultry litter ash (PLA) is a co-product from manure-to-energy systems that originated in response to increased poultry litter (PL) volumes generated in concentrated poultry production regions. Investigating PLA as a crop fertilizer is an alternative solution to balancing poultry and crop regional nutrient cycling in the Commonwealth of Virginia. As the expanding world population places pressure on the poultry industry to meet consumption demands, increased PL production presents an obstacle to identify alternative uses for increased volumes. Currently, Virginia produces 44 million broilers with PL produced predominately in the Shenandoah Valley and Eastern Shore. Likewise, a growing world population places pressure on crop production areas and subsequently finite natural resources used for crop fertilization. Poultry litter ash is an alternative phosphorus (P) and potassium (K) source enhancing transportation logistics, repurposing PL nutrients, and offers dual purpose as a fertilizer and an energy source when compared to PL. Three PLA products [(fluidized bed bulk (FB Bulk), fluidized bed fly (FB Fly), and combustion Mix (CMix)], two manufactured co-products [(granulated poultry litter ash (GPLA), and ash coated urea (ACU)] were evaluated as P, K, and N sources for corn (Zea Mays L.) production in comparison to industry fertilizers [(PL, triple superphosphate (TSP), muriate of potash (KCL), and urea). A comprehensive examination of elemental composition, P speciation, P and K solubility, improved functionality into granulized forms, and field testing were conducted to discern PLA potential as an alternative fertilizer source. Poultry litter ash products were evaluated by total elemental analysis, backscatter-electron dispersive (BSED) microscopy, and X-ray absorption near edge structure (XANES) spectroscopy. Poultry litter ash elemental concentrations were highly variable ranging from 50.6 to 102.0 g P kg -1 and 62.6 to 120.0 g K kg -1 and were comparatively higher than PL concentrations. Phosphorus structures that provided and controlled P solubility were Ca and Ca-Mg-phosphate compounds. Spectroscopy confirmed Ca structures as predominately monetite (dicalcium phosphate anhydrous; CaHPO4; log K ̊ 0.30) and brushite (dicalcium phosphate dihydrate; CaHPO4.2H20; 0.63 log K ̊ ) species that were supported by BSED and elemental stoichiometric ratios (Ca:P; 1.12 to 1.71:1). Additionally, GPLA acidified from FB Fly had higher brushite and monetite percentages described by spectra models, translating into a more soluble Ca-phosphate species when compared to FB Fly original P species. Granulated poultry litter acidulation trials successfully identified a desired granulation point of 29% (14.5 g acid to 50 g PLA) phosphoric acid (75% H3PO4) acidulation. Acidulation dose response relationships created simple linear regression (SLR) equations that sufficiently (R2 > 0.80) described changes in total measurable P and water soluble P, pH, and exothermic reaction temperatures to increasing H3PO4 acidulation. Solubility tests included: sequential extraction, particle size effect on solubility, carbon effect on water soluble P, and Mehlich-1 extraction of PLA sources that confirmed decreased P solubility. A majority PLA P was found in bound plant unavailable fractions (87.7 to 97.7% P of total P). Granulated poultry litter ash had improved P plant available P of 36.0% P of total P. Carbon (C) effects on PLA P were examined by ashing PLA samples in a muffle furnace at 550 ̊C. Differences in total carbon content negatively impacted FB Bulk and CMix total P (1.30 and 4.56 g P kg -1); however, muffle furnace temperatures increased FB Fly total P by 6.74 g P kg -1. All fertilizer products were investigated under field conditions in separate P, K and N corn studies across Virginia coastal plain soils to determine fertilizer effects on corn plant parameters [(most mature leaf (V6), corn ear leaf (R1), and grain (R6)]. Poultry litter P treatments, averaged over rate, recorded highest yield in both years. At eight of nine field sites, FB Bulk resulted in numerically or significantly higher Mehlich-1 concentrations than other P sources post-harvest. Although Mehlich-1 P increased, yield and plant parameters did not; which leads to the conclusion that PLA sources increased soil residual P that did not translate into immediate plant availability recorded within a growing season. Across plant efficacy parameters examined, PLA K is a comparable nutrient source and improved plant parameters when compared to control. Eighteen out of twenty-one plant parameters examined found similar ACU and urea effects on N concentrations. Therefore, ACU is a comparable N source to urea. When compared to industry fertilizer sources, we concluded that PLA is a slowly available P source, decreased P availability negatively affected early plant growth, K is a comparable nutrient source and improved plant parameters compared to control, and ACU effectively provided N to maintain sufficient corn growth. In conclusion, PLA co-products serve as a densified nutrient source that may provide plant available nutrients if processed to aid in nutrient distribution to grain producing areas. Doctor of Philosophy Poultry litter ash (PLA) is a co-product from manure-to-energy systems that originated in response to increased poultry litter (PL) volumes generated in concentrated poultry production regions. Investigating PLA as an alternative crop fertilizer is essential to balancing poultry and crop regional nutrient cycling in the Commonwealth of Virginia. As the expanding world population places pressure on the poultry industry to meet consumption demands, heightened PL production presents an obstacle to identify alternative uses for increased volumes. Currently, Virginia produces 44,683,904 broilers with PL produced predominately in the Shenandoah Valley and Eastern Shore. Likewise, a growing world population places pressure on crop production areas and subsequently finite natural resources used for fertilization vital to maintaining crop yields. Poultry litter ash, a co-product from manure-to-energy systems, is an alternative phosphorus (P) and potassium (K) source enhancing transportation logistics, repurposing PL nutrients, and offers dual purpose as a fertilizer and an energy source when compared to PL. In this dissertation, three PLA products [(fluidized bed bulk (FB Bulk), fluidized bed fly (FB Fly), and combustion Mix (CMix)], two manufactured co-products [(granulated poultry litter ash (GPLA), and ash coated urea (ACU)] were evaluated as P, K, and N source for corn (Zea Mays L.) production in comparison to industry fertilizers (PL, triple superphosphate (TSP), muriate of potash (KCL), and urea). Each of the following chapters provides a comprehensive examination of the following topics: elemental composition, P speciation, P and K solubility, improved functionality into granulized forms, and field testing designed to provide parameters to conclude PLA potential as an alternative P, K and N source. In the second chapter, PLA products were evaluated by total elemental analysis, backscatter-electron dispersive (BSED) microscopy, and X-ray absorption near edge structure (XANES) spectroscopy. Poultry litter ash elemental concentrations are highly variable and are comparatively higher than PL concentrations. Phosphorus structure and species identified Ca as the primary element controlling P structure and subsequent solubility. The third component of this dissertation is granulation trials investigating phosphoric acid effects on granulizing and increasing total and water soluble P. Our results identified 29% (14.5 g acid to 50 g PLA) phosphoric acid acidulation for desired granule size. The third dissertation component examines PLA solubility. The results demonstrated PLA decreased P water solubility when compared to industry fertilizer sources. Granulated poultry litter ash demonstrated improved P plant availability due to the granulation process. The final and fourth dissertation components investigated PLA sources under field conditions in separate P, K and N corn studies across Virginia coastal plain soils to determine fertilizer effects on corn plant parameters. Minority of plant parameters tested revealed P control yielded numerically higher P concentrations than PLA P sources tested. Poultry litter P treatments, averaged over rate, recorded highest yield in both years. At eight of nine field sites, FB Bulk resulted in numerically or significantly higher Mehlich-1 concentrations than other P sources post-harvest. Although Mehlich-1 P concentrations increased, yield and plant parameters did not; which leads to the conclusion that PLA sources increased soil residual P that did not translate into immediate plant availability recorded within a growing season. Across plant efficacy parameters examined, PLA K is a comparable nutrient source and improved plant parameters when compared to controls. The majority of plant parameters examined found similar ACU and urea effects on N concentrations. Therefore, ACU is a comparable N source to urea. When compared to industry fertilizer sources, field results concluded that PLA is a slowly available P source, decreased P availability negatively affected early plant growth, K is a comparable nutrient source and improve plant parameters compared to control, ACU effectively provides N to maintain sufficient corn growth. In conclusion, PLA co-products serve as a densified nutrient source that may provide plant available nutrients if processed to aid in nutrient distribution to grain producing areas.

APA, Harvard, Vancouver, ISO, and other styles

8

Dodson, J. "Wheat straw ash and its use as a silica source." Thesis, University of York, 2011. http://etheses.whiterose.ac.uk/1931/.

Full text

Abstract:

The overall aim of this project was to study the reutilisation of the major ash components, predominantly silica and potassium, in wheat straw combustion residues to form alkali silicate binders for novel inorganic composite boards. Wheat straw of one variety and year was studied in detail on a lab-scale. Studies on the effects of combustion time and temperature show, for the first time, that the inherent alkali in the wheat straw is sufficient to solubilise up to 25% of the silica in the ash at room temperature. Combustion at temperatures below 600 °C gives the highest silica extraction by producing the most alkaline solutions, preventing calcium solubility and maintaining silica in a more reactive form. The first detailed comparisons of the effect of wheat straw variety and growth year on the properties of its combustion residues show that their mineralogical composition, leaching of inorganic components, silica structure and alkalinity can be correlated to the initial elemental composition. Pretreatment of wheat straw by ethanol extraction indicates that this can reduce the potassium and chloride content similar to that achieved by water washing, potentially producing a less problematic material for combustion, without significantly reducing the alkalinity of the combustion residues. This is believed to be the first reported observation of this effect. Pyrolysis of the wheat straw followed by char washing prior to combustion demonstrates improved extractability of the silica present utilising the inherent alkalinity, compared to extraction of the ashes. The leached chars display a lower ash content, lower potassium content, lower chloride content and higher calorific value, making them more suitable for combustion than the initial straw. Finally, the formation of alkali silicate solutions from commercial biomass combustion residues is demonstrated. Biosilicate solutions comparable to commercial potassium silicate solutions are formed by extraction of the bottom ashes. These show potential as binders for inorganic composite boards.

APA, Harvard, Vancouver, ISO, and other styles

9

Joseph, Alain A. "CFB fly ash as a calcium and boron source for radish, rutabaga, and alfalfa." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0019/MQ57300.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Fredriksson, Helena. "Characterization of starch from different sources /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5540-5.gif.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Ardam, Nagaraju. "Study of ASA Algorithms." Thesis, Linköpings universitet, Elektroniksystem, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70996.

Full text

Abstract:

Hearing aid devices are used to help people with hearing impairment. The number of people that requires hearingaid devices are possibly constant over the years, however the number of people that now have access to hearing aiddevices increasing rapidly. The hearing aid devices must be small, consume very little power, and be fairly accurate.Even though it is normally more important for the user that hearing impairment look good (are discrete). Once thehearing aid device prescribed to the user, she/he needs to train and adjust the device to compensate for the individualimpairment.We are within the framework of this project researching on hearing aid devices that can be trained by the hearingimpaired person her-/himself. This project is about finding suitable noise cancellation algorithm for the hearing-aiddevice. We consider several types of algorithms like, microphone array signal processing, Independent ComponentAnalysis (ICA) based on double microphone called Blind Source Separation (BSS) and DRNPE algorithm.We run this current and most sophisticated and robust algorithms in certain noise backgrounds like Cocktail noise,street, public places, train, babble situations to test the efficiency. The BSS algorithm was well in some situation andgave average results in some situations. Where one microphone gave steady results in all situations. The output isgood enough to listen targeted audio.The functionality and performance of the proposed algorithm is evaluated with different non-stationary noisebackgrounds. From the performance results it can be concluded that, by using the proposed algorithm we are able toreduce the noise to certain level. SNR, system delay, minimum error and audio perception are the vital parametersconsidered to evaluate the performance of algorithms. Based on these parameters an algorithm is suggested forheairng-aid. Hearing-Aid

APA, Harvard, Vancouver, ISO, and other styles

12

Xue, Junfeng. "Genes involved in carbon source utilization and pediocin AcH resistance in Listeria." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1456284371&sid=2&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Joel, Abraham. "Surface runoff : a water source for poor farming communities in drylands /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5753-X.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Byström, Olof. "Cost-effective reduction of nonpoint source pollution : five essays on wetlands, policy, and modeling /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5547-2.gif.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Jansén, Jan. "Agriculture, energy and sustainability : case studies of a local farming community in Sweden /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5767-X.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Sarray, Sadreddine. "Proposed Revisions to Procedures for Testing and Evaluating Radiating Noise Sources from Small Firearms, including the ANSI/ASA S12.42-2010 Procedure." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40549.

Full text

Abstract:

The escalating cost of claims for Noise Induced Hearing Loss (NIHL) in the Canadian Armed Forces (CAF) supports the need to review and upgrade current hearing conservation practices. The rise of these escalating costs and the need to protect the military personnel when training in extreme noise conditions has initiated an engineering investigation within the Department of National Defence (DND) and in collaboration with the University of Ottawa, to review the existing standards in the field of hearing protection test and evaluation, to propose technical recommendations and to identify the possible technical problems and gaps impacting the quality of the existing procedures. This study dealt with the estimation of the protection capability of Hearing Protection Devices (HPDs) in the case of high-level impulse noise from small firearms weapons that are a particularly damaging source of noise in military environments, representing an important cause of NIHL. Testing and evaluation based on a system engineering approach have been used in this work introducing: - A new testing approach, based on ANSI/ASA S12.42-2010, for testing HPDs when the impulse noise is generated by a small firearm; - A new evaluation approach for HPD performance, introducing a characterization approach using a sub-band analysis for dealing with impulse noise generated by a small firearm. The effectiveness of HPDs, taking into account the physiological human limitations induced by Bone Conduction (BC), is computed by using an innovative method attempting to better prevent the risk of NIHL when using small firearms.

APA, Harvard, Vancouver, ISO, and other styles

17

Daou, Tamima Bayhom. "The Imami Shii conception of the knowledge of Imam and the sources of religious doctrine in the Formative Period from Hisham b. al-Hakam (d. 179 A.H.) to Kulini (d. 329 A.H.) /." Thesis, Online version, 1996. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.339018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Lapousterle, Jean. "L'influence des groupes de pression sur l'élaboration des normes : illustration à partir du droit de la propriété littéraire et artistique." Paris 2, 2007. http://buadistant.univ-angers.fr/login?url=https://www.dalloz-bibliotheque.fr/pvurl.php?r=http%3A%2F%2Fdallozbndpro-pvgpsla.dalloz-bibliotheque.fr%2Ffr%2Fpvpage2.asp%3Fpuc%3D5442%26nu%3D14.

Full text

Abstract:

Les groupes de pression sont des organisations qui s'adressent aux pouvoirs publics en vue d'obtenir la prise en compte de leurs intérêts dans l'élaboration des normes. A cette fin, ils savent se rendre utiles au législateur, en lui apportant l'information dont il a besoin pour exercer sa mission, ou en favorisant la réception de la norme. Cependant, l'action des groupes de pression n'est pas dénuée d'effets pervers. On constate ainsi que la prise en compte de leurs exigences peut compromettre l'effectivité ou l'intelligibilité de la règle de droit. Dans d'autres hypothèses, il arrive que les déséquilibres de représentation entre les groupes de pression aient une incidence sur le contenu même des normes adoptées. Un tel constat appelle une réflexion de fond sur l'encadrement de l'action des groupes, à laquelle cette thèse tente, en se nourrissant de enseignements du droit comparé, d'apporter une contribution.

APA, Harvard, Vancouver, ISO, and other styles

19

Dumontet, Stefano. "Marine aquatic environment as a source of potential human pathogens : studies on prevalence, ecology and characterisation of Aeromonas spp. and Vibrio vulnificus isolated from marine environment /." Uppsala : Dept. of Veterinary Microbiology, Swedish Univ. of Agricultural Sciences ([Institutionen för veterinärmedicinsk mikrobiologi], Sveriges lantbruksuniv.), 2002. http://epsilon.slu.se/avh/2002/91-576-6370-X.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Slobodan, Šupić. "Primena pepela nastalog sagorevanjem žetvenih ostataka kao mineralnog dodatka u cementnim kompozitima." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2019. https://www.cris.uns.ac.rs/record.jsf?recordId=110861&source=NDLTD&language=en.

Full text

Abstract:

U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primjene biopepela, nastalog sagorjevanjem žetvenih ostataka, kao mineralnog dodatka u cementnim kompozitima: malterima i betonima. Istraživanje je zasnovano na komparativnoj analizi 27 vrsta maltera u kojima je varirana vrsta biopepela i vrsta sitnozrnog agregata i 12 vrsta betona koje se razlikuju u vrsti veziva i u krupnom agregatu. Na očvrslom malteru su ispitani: konzistencija, čvrstoća pri pritisku i kapilarno upijanje vode, a na očvrslom betonu ispitivani su kapilarno upijanje vode, skupljanje pri sušenju, čvrstoća pri pritisku, dinamički modul elastičnosti, otpornost na habanje, vodonepropustljivost i čvrstoća na savijanje. Istaknuto je da se primjenom biopepela kao zamjene dijela cementa mogu dobiti konstrukcijski malteri i betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama. The dissertation presents the results of an own experimental research on the possibility of using biomass ash as a mineral additive in cement composites: mortar and concrete. The research is based on a comparative analysis of 27 types of mortars in which the type of biomass ash and the type of fine-grained aggregate were varied, as well as 12 types of concrete that differ in the type of binder and coarse aggregate. Following properties were tested on hardened mortars: consistency, compressive strength and capillary water absorption, and on hardened concrete: capillary water absorption, drying shrinkage, compressive strength, dinamic modulus of elasticity, wear resistance, waterpermeability and flexural strength. It was pointed out that biomass ash can be used as a replacement of a part of cement, thereby obtaining satisfactory physical and mechanical characteristics.

APA, Harvard, Vancouver, ISO, and other styles

21

Miloš, Šešlija. "Анализа примене отпадних и рециклираних материјала за израду порозног бетонског коловоза". Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107503&source=NDLTD&language=en.

Full text

Abstract:

У дисертацији су анализиране мешавине за израду порозног бетонског коловоза. Пројектовано је укупно 12 различитих врста мешавина. За справљање бетонских мешавина коришћене су фракције природног и рециклираног агрегата. Електрофилтерски пепео, који је отпадни материјал из термоелектрана, коришћен је као минерални додатак, којим је замењен део цемента. Справљено је шест мешавина са рециклираним агрегатом и шест мешавина са природним агрегатом. Лабораторијска испитивања су обухватила испитивање чврстоће при притиску бетона након: 7, 28, 56 и 84 дана, чврстоће при савијању (након 28, 56 и 84 дана), модул еластичности (статички и динамички), отпорност према хабању, коефицијент водопропустљивости и порозност. Добијени резултати потврдили су постављене хипотезе да је са рециклираним агрегатом и електрофилтерским пепелом могуће пројектовати и извести порозни бетонски коловоз. U disertaciji su analizirane mešavine za izradu poroznog betonskog kolovoza. Projektovano je ukupno 12 različitih vrsta mešavina. Za spravljanje betonskih mešavina korišćene su frakcije prirodnog i recikliranog agregata. Elektrofilterski pepeo, koji je otpadni materijal iz termoelektrana, korišćen je kao mineralni dodatak, kojim je zamenjen deo cementa. Spravljeno je šest mešavina sa recikliranim agregatom i šest mešavina sa prirodnim agregatom. Laboratorijska ispitivanja su obuhvatila ispitivanje čvrstoće pri pritisku betona nakon: 7, 28, 56 i 84 dana, čvrstoće pri savijanju (nakon 28, 56 i 84 dana), modul elastičnosti (statički i dinamički), otpornost prema habanju, koeficijent vodopropustljivosti i poroznost. Dobijeni rezultati potvrdili su postavljene hipoteze da je sa recikliranim agregatom i elektrofilterskim pepelom moguće projektovati i izvesti porozni betonski kolovoz. In the dissertation, mixtures for the production of pervious concrete pavements are analyzed. The project has a total of 12 different types of mixtures. For the preparation of concrete mixtures, the fractions of natural and recycled aggregates were used. Fly ash, which is a waste material from thermal power plants, was used as a mineral supplement, which replaced a part of cement. Six mixtures with a recycled aggregate and six mixtures with a natural aggregate were collected. Laboratory tests included: compressive strength after 7, 28, 56 and 84 days, felxural strength (after 28, 56 and 84 days), modulus of elasticity (static and dynamic), abrasion, permeability and porosity. The obtained results confirmed the hypotheses that it is possible to design and execute a previous concrete pavement with a recycled aggregate and fly ash.

APA, Harvard, Vancouver, ISO, and other styles

22

Ahmad, Riadh. "Al-Husyan Ibn 'Ali: a Study of his Uprising and Death Based on Classical Arabic Sources (3rd and 4th Century A.H./9th and 10th Century A.D.)." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=108795.

Full text

Abstract:

This dissertation deals with al-Husayn's uprising and death based on the classical Arabic sources. It is argued that al-Husayn's uprising and opposition to Yazïd's caliphate were directly connected to the matter of the caliphate and the caliph's qualifications. He refused to recognize Yazïd's caliphate because he considered it as illegitimate due to the fact that Yazïd was not qualified to assume such an important office. It is also argued that because of Mu-c-âwiya, who attempted to secure Yazïd's succession by forcing all Muslims to pay homage to him, Yazïd became caliph. [...] Ce mémoire est une étude de la révolte et mort de al-Husayn qui se base sure les sources arabes classiques. Nous proposons que la révolte de al-Husayn et son opposition au califate de Yazïd sont étroitement liées à l'institution du califat et aux conditions que le calife devait remplir. Il a refusé de reconnaître le califat de Yazïd, le considérant illégitime, puisque Yazïd n'avait pas les compétences pour occuper la charge d'un devoir aussi important. Nous proposons d'ailleurs que c'est à cause du califate de Mu-c-âwiya, qui, lui a tenté d'imposer la succession de Yazïd en obligeant les Musulmans à lui rendre hommage, que Yazïd est devenu calife. [...]

APA, Harvard, Vancouver, ISO, and other styles

23

Ahmad, Riadh. "Al-Ḥusayn ibn 'Alī : a study of his uprising and death based on classical Arabic sources (3rd and 4th century A.H.9th and 10th century A.D.)". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102780.

Full text

Abstract:

This dissertation deals with al-Ḥusayn's uprising and death based on the classical Arabic sources. It is argued that al-Ḥusayn's uprising and opposition to Yazid's caliphate were directly connected to the matter of the caliphate and the caliph's qualifications. He refused to recognize Yazid's caliphate because he considered it as illegitimate due to the fact that Yazid was not qualified to assume such an important office. It is also argued that because of Mu`awiya, who attempted to secure Yazid's succession by forcing all Muslims to pay homage to him, Yazid became caliph. Wanting to remove the real meaning of the caliphate and intending to transform it to a kingship (mulk) inherited among his offspring, Mu`awiya himself rejected the principle of the early Companions of the Prophet by choosing the caliph. Al-Ḥusayn refused to listen to those who advised him to submit to the established authority (de facto) and to enter into whatever the community had entered into and agreed upon. Yazid's caliphate, in al-Ḥusayn's eyes, was a deviation from the Sunna of the Prophet and the conduct of the Rightly Guided Caliphs, and represented corruption in the community of his grandfather. As the Prophet's grandson, he believed that he was committed to following in the footsteps of his grandfather and was more responsible than anybody else for preventing corruption. Even when he became convinced of the Kufans' failure to stand with him, al-Ḥusayn refused to give the bay`a to Yazid and also felt obliged to revolt against him. Furthermore and apart of his strategy, he did decide to take his family with him in order that they would play a significant role after his death. Amongst the results obtained during this research were the three different patterns of writing in our sources; namely, pro-Sunni, pro-Shi`i and a moderate, who escaped being classified as pro-Sunni or pro-Shi`i.

APA, Harvard, Vancouver, ISO, and other styles

24

Hamdan, A. H. A. "The literature of Medina in the twelfth century A.H. (eighteenth century A.D.) examined from contemporary sources, with a critical edition of one of these sources : Al-Akhabar al-Ghariba fiDhikr ma waqa a bi-Tayba al-Habiba by one Ja Far Hashim al-Husayni." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376293.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Grondard, Clément. "Analyse des effets de l'exercice physique dans des modèles souris de maladies humaines sévères touchant le motoneurone." Paris 6, 2007. http://www.theses.fr/2007PA066146.

Full text

Abstract:

L’amyotrophie spinale infantile (ASI) et la sclérose latérale amyotrophique (SLA) sont deux maladies neurodégénératives très graves. Nous avons analysé les effets de l’exercice physique dans des modèles souris de ces deux pathologies. La course est bénéfique dans le cas de l’ASI. Elle augmente la durée de vie, permet une neuroprotection et diminue l’atrophie musculaire due à la maladie. L’étude comparée des effets de la nage et de la course chez un modèle souris de la SLA montre que les deux types d’exercice sont neuroprotecteurs. Mais alors que la course protège plutôt les motoneurones d’unités motrices lentes, la nage préserve plutôt ceux des unités motrices rapides. Que ce soit dans l’ASI ou la SLA, l’exercice physique est très bénéfique. Ces études ouvrent la voie au développement de programmes d’entraînement pour les patients, permettront d’identifier ces mécanismes et de proposer de nouvelles voies thérapeutiques.

APA, Harvard, Vancouver, ISO, and other styles

26

La, Rupelle Aude de. "Le volcanisme ignimbritique des canyons Ocoña - Cotahuasi (Sud du Pérou) : chronostratigraphie, sources et liens avec la surrection andine." Thesis, Clermont-Ferrand 2, 2013. http://www.theses.fr/2013CLF22379.

Full text

Abstract:

La Cordillère des Andes, issue de la subduction de la plaque Pacifique sous le continent Sud-Américain, est un système orogénique propice à la formation de grands systèmes volcaniques acides, dans lesquels coexistent des produits d’éruptions volcaniques explosives de grandes magnitudes et des laves et dômes, associés à des calderas mono- ou polygéniques. Ce mémoire de thèse apporte de nouvelles connaissances sur certains systèmes volcaniques acides du Sud du Pérou, dont les produits affleurent dans les canyons d’Ocoña-Cotahuasi-Maran (OCM). Ces canyons, les plus profonds des Andes (3 à 3,5 km), résultent de la combinaison des processus de soulèvement tectonique, d’incision, et d’érosion depuis 15 Ma. Les imposantes séries ignimbritiques exposées dans cette région (env. 10000 km²), témoignent de l’existence d’un volcanisme explosif de grande ampleur, associé à des systèmes acides peu connus d’après les études antérieures. Cette étude vise tout d’abord à obtenir une chrono-stratigraphie améliorée des événements ignimbritiques (groupes, unités) dans la région OCM pour mieux connaître les récurrences des super-éruptions dans cette région au cours des derniers 25 Ma. Ensuite, nous cherchons à localiser les sources des grandes unités et à identifier les éventuelles structures d’effondrement associées (calderas). Pour ce faire, nous avons combiné diverses techniques, associant l’étude de la stratigraphie et de la lithologie des dépôts volcaniques, les datations par la méthode 40Ar-39Ar des principales unités ignimbritiques et coulées de lave, l’imagerie satellitaire (Landsat, SPOT) et la pétrologie (assemblages minéralogiques, étude des textures et des compositions chimiques) et enfin, les mesures de densité et d’anisotropie de susceptibilité magnétique des ignimbrites (ASM) pour analyser les directions d’écoulement et tenter de localiser leurs sources. Ainsi, les résultats nous ont permis d’identifier huit événements ignimbritiques, dont six majeurs, datés entre ~24 Ma et ~2 Ma. Les âges des grandes unités (Nazca, Alpabamba, Huaylillas, Caraveli, Sencca inférieure et supérieure) montrent une récurrence moyenne de l’ordre de 4-5 Ma depuis 25 Ma. Les lithologies sont assez semblables, bien que les degrés de soudure varient beaucoup, allant de produits meubles jusqu’aux faciès eutaxitiques. L’étude pétrologique révèle des assemblages de minéraux assez homogènes, les paragenèses étant dominées par le quartz, le feldspath, la biotite, l’amphibole et des oxydes. Les volumes bruts des unités principales que nous avons déterminés se situent entre ~40 et ~500-800 km3. Cependant, il ne s’agit que de valeurs minimales, puisque nous considérons que les volumes initiaux sont au moins le double ou le triple, probablement dans la gamme ~100 à ~2400 km3. La distribution des unités ignimbritiques d’OCM et les résultats des analyses ASM désignent plusieurs zones sources. L’unité de Caraveli provient de la caldera de Trapiche, qui contient le lac Parinacochas. Cette structure que nous identifions, d'un diamètre de ~22 km, est située dans un bassin tectonique allongé selon la direction N-S. Elle est occupée dans sa partie ouest par un dôme résurgent de 800 m de haut, le Cerro Trompo Orjo. Les unités Huaylillas et Alpabamba, ainsi que les groupes Sencca (inférieure et supérieure) seraient issus d’une source entièrement recouverte par le massif volcanique quaternaire du Nevado Coropuna. Des estimations de volumes éruptifs suggèrent une atténuation significative du volcanisme ignimbritique depuis 9 Ma, peut-être liée à la maturation orogénique de l’Altiplano-Puna. En profondeur, le magmatisme a probablement contribué à l’épaississement crustal par adjonction de grands volumes de magma. (...) The Andes, resulting from the subduction of Pacific plate under South-America continental plate, is an orogenic system suitable for large acidic volcanic systems formation. These structures display at the same time volcanic products from high magnitude explosive eruptions, lavas and domes, and mono- or polygenetic calderas. This manuscript brings a new expertise on some of the acidic volcanic systems in South Peru, which products outcrop in the Ocoña - Cotahuasi - Maran canyons (OCM). This canyons system, one of the deepest worldwide (up to 3.5 km), was created by combined tectonic uplift, incision and erosion processes since 15 Ma. Voluminous ignimbritic series widespread in this region (around 10000 km2) are evidences for a past high amplitude explosive volcanic activity related to little-known acidic systems. The topic of this study is to obtain an enhanced chrono-stratigraphy of the OCM region ignimbritic succession (groups and units). This would provide a better knowledge on the regional super-eruptions recurrence since the last 25 Ma. Then, we focus on localizing the largest ignimbrites sources and identify the possible related collapse structures (calderas). For that purpose we combine several studies, from stratigraphy, deposits lithology to 40Ar-39Ar dating of the main ignimbritic units and lava flows. We also use satellite imagery (Landsat, SPOT) and petrology (mineralogical assemblage, textures and geochemical composition). Finally, we measure the ignimbrites density and anisotropy of magnetic susceptibility (AMS) to determine their flowing directions and estimate their sources locations. Thus, the results let us identify eight ignimbritic events among which, six happened between ~24 Ma and ~2 Ma. The main units ages (Nazca, Alpabamba, Huaylillas, Caraveli, lower and upper Sencca) show an average recurrence of 4-5 Ma since 25 Ma. Lithologies are similar even if welding degrees ranges are spread from loose deposits to eutaxitic facies. Petrological study show quite homogeneous mineralogical assemblages since quartz, feldspar, biotite, amphibole and oxydes dominate the paragenesis. Our estimations of the main units bulk volumes range from ~ 40 to ~ 500-800 km3. However, these are only minimum values since we consider that initial volumes as twice or three times higher, probably in the range of ~100 to ~2400 km3. The OCM ignimbrite flow units distribution and the AMS study results indicate several regions as sources for these units. Caraveli unit flowed from Trapiche caldera in which the Parinacochas lake rests. This structure is estimated to be ~22 km of diameter and lays in a N-S orientated tectonic basin. Its western part is occupied with a 800 m high resurgent dome, named Cerro Trompo Orjo. Alpabamba and Huaylillas units, as Sencca units (lower and upper) would come from a source presently entirely covered with the quaternary massif of Nevado Coropuna. Estimations of eruptive volumes recall an important decrease of ignimbritic volcanism since 9 Ma, which might be related to simultaneous Altiplano-Puna orogenic growing. It is supported that deep magmatism have probably contributed to crustal thickening thanks to the addition of large volumes of magma. These results also involve that canyons erosion and incision would have taken place at a rate ranging from 150 to 500 m/Ma during the last 13 Ma. Given that the large-volume acidic system studied in this work is considerable, further research are necessary to improve these results

APA, Harvard, Vancouver, ISO, and other styles

27

Biondi, Olivier. "Identification des mécanismes de neuroprotection activés par l’exercice physique dans un modèle souris d’amyotrophie spinale de type 2." Paris 6, 2008. http://www.theses.fr/2008PA066114.

Full text

Abstract:

L’amyotrophie spinale infantile (ou ASI) est une maladie neuromusculaire de l’enfant, induite par un faible niveau de protéine SMN (pour Survival of Motor Neuron) présent dans l’organisme et pour laquelle aucune thérapie curative n’est connue à ce jour. Nous montrons, par ce travail, que le retard de maturation des unités motrices, observé chez les souris ASI de type II, est corrélé avec la mort motoneuronale. L’exercice physique retarde la mort motoneuronale et induit une accélération de la maturation des unités motrices. En outre, l’exercice physique est capable d’augmenter spécifiquement l’expression du gène codant pour la sous unité activatrice du récepteur au NMDA et majoritaire dans les motoneurones, nommée NR2A, qui est sous exprimée dans la moelle épinière des souris ASI de type II. En conséquence, inhiber l’activité du récepteur au NMDA bloque les effets de l’exercice sur le développement musculaire, la neuroprotection et la durée de vie. Ainsi, restaurer la fonction du récepteur au NMDA pourrait être une approche thérapeutique prometteuse dans le traitement de l’ASI.

APA, Harvard, Vancouver, ISO, and other styles

28

Johnson, Laura Marie. "Establishing broadcast monitoring as Open Source Intelligence : the BBC Monitoring Service during the Second World War." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/establishing-broadcast-monitoring-as-open-source-intelligence(6f680ea6-3fb7-41b9-a93d-321ce446e835).html.

Full text

Abstract:

Given the recent surge of interest in Open Source Intelligence (OSINT), surprisingly little attention has been devoted to existing open source agencies or their historic role. As the first full length academic study of the BBC Monitoring Service, this thesis seeks to examine one of the earliest historic attempts to systematically manage and exploit publicly available, open source information for intelligence purposes. It utilises the Imperial War Museum’s rarely used collection of BBC Monitoring transcripts, in conjunction with traditional archival sources and oral interviews, to trace the origins, processes and institutional structure developed by the Monitoring Service during its formative years. This study further assesses the collection priorities of BBC Monitoring during World War Two, traces the historic flow of monitored material around the wartime Government and BBC, and establishes the institutional role of BBCM in the conduct of Britain’s war effort. Three case study chapters, focusing on the outbreak of war, Dunkirk and D-Day, particularly assess the process and detailed collection priorities of the Monitoring Service during key events throughout the war. This study thus makes a contribution to the historic picture of British intelligence during World War Two, and is bound to encourage future study of the BBC Monitoring Service and its archives. Overall, the BBC Monitoring Service is judged a historic success story. This thesis argues that this success can be attributed to three key qualities developed during the wartime period: trust, breadth, and adaptability. The organisation established a relationship of trust with the Government; developed and maintained a remarkable breadth of broadcast coverage; and showed a constant ability to adapt to both customer demands and changing strategic priorities.

APA, Harvard, Vancouver, ISO, and other styles

29

Richards, Samia. "On-site wastewater treatment systems as sources of phosphorus and other pollutants in rural catchments : characteristics and tracing approaches." Thesis, Bangor University, 2017. https://research.bangor.ac.uk/portal/en/theses/onsite-wastewater-treatment-systems-as-sources-of-phosphorus-and-other-pollutants-in-rural-catchments-characteristics-and-tracing-approaches(cf2d6620-06b2-4737-8626-c6b736717585).html.

Full text

Abstract:

This thesis investigated the influence of septic tanks (ST) on stream water quality. Characterisation of septic tank effluent (STE) revealed that STE were enriched in phosphorus (P), nitrogen (N), organic matter (OM) and metals relative to stream waters and large proportions of these parameters were present in the soluble reactive forms. Human factors such as tank design, number of users, dishwasher use and infrequent desludging significantly (P < 0.05) influenced effluent quality. ST that received roof runoff had reduced effluent retention time, while infrequent desludging was linked to increased OM, bacteria and P concentration in the effluent. Tanks that served larger numbers of people had elevated microbial abundance, P and N concentrations. Effluent composition was not consistent throughout the year, but exhibited similarity in warmer drier months that was different from effluent in colder wetter months for biological oxygen demand and heavy metals. Effluent attenuation in a test soil revealed that 14%-35% of P was attenuated by sorption processes, while saccharin was strongly attenuated by soil microbial degradation. The complex composition of STE reduced the ability of the test soil to adsorb P, as other substances in the effluent were competing for soil binding sites. Calculated P annual loadings from STE were 0.797 and 0.956 kgP/person/year for water usage of 150 and 180 l/person/day, respectively, while, effluents P load from detergents was 0.154 kg P/person/year. Newly developed tracing studies showed that ratios of chloride to other effluent indicators (e.g. EC, NH4-N, TSS, turbidity, total coliforms, sucralose, saccharin and Zn) and the detection of effluent tryptophan-like peak by fluorescence spectroscopy may be useful in tracking effluent discharge to streams with low levels of dilution. However, effluent caffeine and saccharin were more effective tracers in streams with low and high levels of dilutions. A single individual tracer alone was not sufficient to evaluate STE contamination sources, but combined chemical and physical tracing approaches show promise as tools to identify STE inputs that continue to pose risks to watercourses and where mitigation measures could be effectively targeted.

APA, Harvard, Vancouver, ISO, and other styles

30

Vieira, Mathieu. "Régulation de l'expression du gène Nodal lors de la différenciation des cellules souches embryonnaires." Thesis, Sorbonne Paris Cité, 2018. https://theses.md.univ-paris-diderot.fr/VIEIRA_Mathieu_2_va_20180930.pdf.

Full text

Abstract:

L'influence des signalisations ACTIVINE/NODAL et FGF sur les cellules souches embryonnaires murines (mESC) déclenchent leurs différenciations en cellules analogues aux EpiSC (EpiLCs). Cette différenciation modifie les niveaux d'expression des facteurs de pluripotence et il va promouvoir un changement global de l'expression génique. C'est notamment le cas pour le gène Nodal. Alors que son expression est dépendante des facteurs de transcription liés à son enhancer HBE dans les mESCs, il devient principalement dépendant de sa boucle de rétro-contrôle positive médiée par l'enhancer ASE (dépendant de la signalisation ACTIVINE/NODAL) dans les EpiLCs. De précédentes études effectuées au laboratoire ont mis en évidence que les mESCs où HBE a été enlevé sont incapables d'exprimer Nodal une fois différenciées en EpiLCs, démontrant que, bien qu'HBE ne soit pas nécessaire à l'expression de Nodal en EpiLC, sa présence est requise en mESC pour assurer l'expression ultérieure de Nodal en EpiLC (Papanayotou et al 2014). Cette découverte soulève la question de savoir si HBE exerce son contrôle directement sur ASE ou bien via d'autres régions régulatrices du locus. On peut également se demander par quels intermédiaires moléculaires (changements chromatiniens) se contrôle à lieu et quels sont les facteurs impliqués (modificateurs ou remodeleurs de la chromatine, facteurs de pluripotence). Pour répondre à ces questions j'ai tout d'abord généré des délétions spécifiques de HBE et ASE dans les mESCs en utilisant l'outil d'édition génétique CRISPR/Cas9. J'ai ensuite caractérisé l'impact de ces délétion sur l'expression de Nodal par RT-qPCR et imagerie en temps réel d'un rapporteur NodalcondHBE-YFP endogène. Alors que HBE est essentiel à l'expression de Nodal en mESC j'ai également découvert que ASE contribue à l'expression de Nodal dans ces cellules. Pour disséquer le fonctionnement de HBE j'ai généré des lignées de mESCs manquant des régions de HBE qui sont conservé chez les mammifères. L'impact de ces délétions m'ont permis d'identifier le domaine HBE2 comme étant responsable de l'activité transcriptionnelle de HBE dans les mESCs. Ce domaine contribue également à l'activité de Nodal dans les EpiLCs, démontrant que bien que HBE ne soit pas essentiel à l'expression de Nodal en EpiLC, il participe tout de même à son expression. Aucun domaine de HBE ne semble être seul responsable du contrôle de l'activation de l'ASE dans les EpiLCs. Cette fonction semble ainsi être distincte de l'activité transcriptionnelle de HBE. Une analyse par ChIP-qPCR dans les mutants HBE-/- et ASE-/- ont révélé que les modifications d'histones présentes sur le promoteurs et sur ces enhancers étaient différentes. Ces données nous laissent envisager que la maintenance du paysage épigénétique du locus Nodal implique des interactions entre ces différents éléments régulateurs. L'analyse de différentes données d'immuno-précipitation de la chromatine ont mis en évidence une liste de facteurs de transcription recrutés au locus Nodal. Différents éléments suggèrent que des facteurs de transcription présents sur ASE contrôlent son activité et sont affectés par la présence de HBE. Ce travail mets en lumière un mécanisme de régulation génique inédit. Ce travail est également un premier pas vers la mise en évidence d'un nouveau mécanisme responsable de la réorganisation de la régulation transcriptionnelle du génome au cours de la différenciation des mESCs en EpiLCs Exposure of embryonic stem cells (mESCs) to ACTIVIN/NODAL and FGF signaling initiates their differentiation into EpiSC-like cells (EpiLCs). This exposure triggers changes in the expression levels of pluripotency factors, and promotes a global shift in gene expression. Remarkably, most of the genes that maintain their expression during this differentiation also undergo a shift in their regulation from one enhancer to another. This is notably the case of the Nodal gene itself. While its expression is dependent on pluripotency factors interacting with its enhancer HBE in mESCs, it is primarily dependent on its auto-regulatory (ACTIVIN/NODAL signaling-dependent) ASE enhancer in EpiLCs. Work in the lab has however shown that mESCs where HBE has been removed are unable to express Nodal once they are differentiated into EpiLCs, revealing that, although EpiLCs do not require HBE to express Nodal, its presence is required in mESCs to ensure later Nodal expression in EpiLCs (Papanayotou et al., 2014). One question raised by this finding is whether HBE exerts its control over Nodal expression solely via its interaction with the promoter or whether it involves HBE directly influencing ASE or other Nodal regulatory regions. Another concerns the nature of the molecular means (chromatin changes) deployed to exert this control and the identity of the factors involved (chromatin remodelers and modifiers, pluripotency factors). To answer these questions I first started to generate specific deletions of HBE and ASE in mESCs using CRISPR/Cas9-mediated genome-editing. I then characterized the impact of these deletions on Nodal expression using qPCR and live imaging of a knocked-in NodalcondHBE-YFP reporter. Although HBE is essential for Nodal expression in mESCs, I found that ASE also contributes to Nodal expression in these cells. To dissect HBE functions I generated mESC lines deleted for sequence conserved subdomains of HBE. Analysis of the impact of these deletions allowed me to find that only one of these subdomains, HBE2, is essential for HBE transcriptional activity in mESC. This subdomain also contributes to Nodal expression in EpiLCs, highlighting the fact that although HBE is not essential to Nodal expression in EpiLCs it does contribute to maintaining its level. However, in contrast to the deletion of the entire HBE, none of these subdomains deletions affected the ability of ASE to drive Nodal expression in EpiLCs, indicating that the distinct functions of HBE in the regulation of Nodal expression can be experimentally dissociated and their molecular basis investigated. Furthermore, ChIP-qPCR analyses revealed that the deletion of HBE or ASE both affected histone mark profiles at the promoter and at the other regulatory element, supporting the view that the maintenance of the epigenetic landscape at the Nodal locus involves multiple interactions between its various regulatory elements. The analysis of ChIP-seq datasets and ChIP-qPCR results has allowed me to compile a list of transcription factors known to bind the Nodal locus. Interestingly, key transcription factors controlling ASE activity could be affected by the presence of HBE. This work unfolds a novel mechanism of gene regulation involving enhancer interaction. This thesis is also the first step towards revealing a new mechanism at place during the reorganization of the transcriptional landscape during mESC to EpiLC differentiation

APA, Harvard, Vancouver, ISO, and other styles

31

Falk, Lissel Linus. "Pass-by noise contribution analysis of electric vehicles." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159271.

Full text

Abstract:

In the modern urban lifestyle, more and more people are exposed to noise pollution in form of traffic noise. As a response to this, the automotive OEMs (Original Equipment Manufacturer) are put under pressure to reduce the emitted noise from vehicles. To be able to meet the upcoming, stricter regulations, the automotive OEMs seeks new techniques to be able to front load the pass-by noise engineering in the vehicle development process and to identify and understand the different sources that contributes to the exterior noise.Earlier exterior sources ranking using ASQ (Airborn Source Quantification) with an energetic approach during pass-by noise test has yielded very good and reliable results for an ICE (Internal Combustion Engine) vehicle.In this Master Thesis, two exterior source ranking methods have been tested and evaluated for an electric vehicle during in-room pass-by noise test. The two methods were: ASQ and OPA (Operational Path Analysis). In total, five models were built from the two methods and each model was evaluated for, in total, three driving conditions corresponding to the current ISO362-1:2007 and the proposed, revised version.The results show that the ASQ models are not capable to correctly estimate the engine contribution due to its high tonality. Moreover, it was seen that the energetic ASQ model is very sensitive to small changes. Both ASQ models underestimated the tire noise.The OPA model on the other hand managed to estimate the total contribution very well. Both the engine contribution and the tire contributions are well estimated. Nevertheless, OPA as method has several weaknesses and building an OPA model is not a straightforward task. Its weaknesses and the process to reach a final OPA model are discussed in this thesis.It was seen that one of the most crucial steps in an OPA model is to have clean references to get meaningful results. A MIMO-FIR filter was therefore used to filter out engine harmonics from the tire references. Its principles and importance for the end results are also discussed.Included is also an overview of the basic principles in TPA (Transfer Path Analysis), ASQ, OPA and in room pass by noise test as well as a description of the test campaign.

APA, Harvard, Vancouver, ISO, and other styles

32

Alghamdi, Yousef Gamaan A. "N-methyl-N’, N’-dimethylethylene-/-propylene-diaminodithiocarbamato-metal complexes as single source precursors for metal sulfide semiconductors materials." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/nmethyln-ndimethylethylenepropylenediaminodithiocarbamatometal-complexes-as-single-source-precursors-for-metal-sulfide-semiconductors-materials(4a7b739b-0f61-4610-a149-c79a7c09b4d4).html.

Full text

Abstract:

A series of N-methyl-N’,N’-dimethylethylene-/-propylene-diaminodithiocarbamato-metal complexes [M(S2CN(Me)(CH2)nN(Me)2)2] (M = Zn, Cd, Cu, Ni; n = 2 or 3), [M(S2CN(Me)(CH2)nN(Me)2)3] (M = Co, In; n = 2 or 3), [M(S2CN(Me)(CH2)nN(Me)2)] (M = Ag; n = 3) has been synthesized and characterised by microelemental analysis, NMR (1H, 13C), IR and some by X-ray crystallography. X-ray single crystal structures for [M(S2CN(Me)(CH2)nN(Me)2)2] (M = Zn, Cd, n = 2 or 3) and [M(S2CN(Me)(CH2)nN(Me)2)3] (M = In; n = 2 or 3) have been determined. Zinc and cadmium structures are polymers. All polymerise through the nitrogen of dimethylamino group to the metal atoms. Both indium structures are monomers where each indium is bonded with six sulphur atoms from three bidentate dithiocarbamato ligands.All twelve metal complexes were solids and stable to air and moisture for periods of several months hence potentially useful as single source precursor for metal sulfide thin films. Metal sulfide thin films including zinc sulfide, cadmium sulfide, copper sulfide, nickel sulfide, cobalt sulfide, indium sulfide, copper indium sulfide, silver indium sulfide, and cadmium zinc sulfide were deposited by aerosol assisted chemical vapour deposition (AACVD) method. Deposition from each precursor was carried out at three different (300, 400 and 500 °C) temperatures to investigate the effect of deposition temperature on the size and shape of crystallites as well as phase of the material. All deposited films were characterized by powder X-ray diffraction (p-XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and atomic force microscopy (AFM). Mostly good quality, adhesive and specular thin films of these materials were obtained. p-XRD showed significant changes in the phase of materials depending upon the growth temperature. SEM and AFM images showed the morphology of the films was strongly linked to the deposition temperature. This is the first systematic study on N-methyl-N’,N’-dimethylethylene-/-propylene-diaminodithiocarbamatometal complexes and their use as single source precursors for the metal sulfide thin films.

APA, Harvard, Vancouver, ISO, and other styles

33

Dutertre, Martin. "Oncogenèse ciblée dans les gonades de souris transgéniques et établissement de lignées de cellules de Sertoli exprimant l'hormone anti-müllerienne (amh) : Contribution à l'étude de la régulation de la production d'amh." Paris11, 1998. http://www.theses.fr/1998PA11T027.

Full text

Abstract:

L'hormone anti-Müllérienne (AMH) est impliquée dans la différenciation sexuelle foetale des Mammifères : produite exclusivement par les gonades mâles, elle induit la régression des canaux de Müller, ébauches de l'utérus. L'AMH, dont le gène a été identifié chez plusieurs espèces, est une glycoprotéine de la superfamille des TGFβ. Elle est produite exclusivement par les cellules de Sertoli des testicules chez les mâles prépubères et, plus faiblement, par les cellules de Sertoli testiculaires et les cellules de la granulosa ovarienne chez les individus pubères et adultes. Chez la souris mâle, nous avons trouvé que le taux sérique d' AMH chute parallèlement au taux de ses ARNm, au début de la puberté. En utilisant des souris mutantes insensibles aux androgènes ou dépourvues de cellules germinales méïotiques, nous avons pu suggérer une répression par les androgènes et par la méïose et une stimulation par la FSH de la sécrétion d'AMH chez le mâle postnatal. Par ailleurs, nous avons généré des souris transgéniques pour 3,6 kb 5'-flanquantes du gène de l'AMH humaine, couplées soit à l'oncogène du virus SV40 (souris AT), soit à un minigène de l' AMH humaine. L'analyse de l'expression de ces transgènes suggère que ces 3,6 kb contiennent des régions régulatrices transcriptionnelles activées dans les cellules de Sertoli immatures et dans les cellules de la granulosa de l'adulte. Les souris AT adultes développent des tumeurs testiculaires de Sertoli et des tumeurs ovariennes de la granulosa et nous avons établi des lignées cellulaires à partir de gonades de ces souris. Par northern blot des ARN totaux, de nombreux ARNm caractéristiques des cellules de Sertoli sont détectables dans toutes les lignées testiculaires, alors que ceux de l'AMH ne le sont que dans les lignées prépubères (prétumorales). L'une d'elles (SMATl) a été clonée, a un profil d'expression génique en accord avec un état immature des cellules de Sertoli et, jusqu'à plus de 30 repiquages, sécrète de l'AMH et exprime ses ARNm. Etant le premier modèle cellulaire exprimant stablement le gène endogène de l'AMH en culture in vitro, elle devrait être utile pour étudier les mécanismes cellulaires et moléculaires des régulations de l'expression de cette hormone. Une lignée cellulaire dérivée de tumeurs ovariennes devra être caractérisée davantage pour confirmer sa différenciation de type granulosa. Nos lignées cellulaires gonadiques exprimant les ARNm du récepteur de l'AMH (AMHR-II), elles devraient être utiles pour étudier sa signalisation et les effets autocrines de l'AMH. Nos lignées cellulaires gonadiques et les souris AT servent aussi de modèles pour étudier l'intérêt de l'AMH et de l'AMHR-II comme marqueurs moléculaires des tumeurs de la granulosa de l'ovaire, qui représentent 6 à 10% des tumeurs malignes de l'ovaire chez la femme.

APA, Harvard, Vancouver, ISO, and other styles

34

Kanan, Safwan. "Modelling of a solar pond as a combined heat source and store to drive an absorption cooling system for a building in Iraq." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/modelling-of-a-solar-pond-as-a-combined-heat-source-and-store-to-drive-an-absorption-cooling-system-for-a-building-in-iraq(1d356a21-e8ab-4491-9ebb-3be2caf0f092).html.

Full text

Abstract:

This research studies the performance of a salinity gradient solar pond driving an absorption cooling system, as an alternative to a conventional electrically powered cooling system, to provide cool air for a modern single family house in the hot dry climate of Baghdad, Iraq. The system comprises a salinity gradient solar pond, a hot-water-fired absorption water chiller, a chilled-water cooling coil which cools the air in the house, and a cooling tower which rejects heat to the ambient air. Hot brine from the pond circulates through a heat exchanger, where it heats water that is then pumped to the chiller. This arrangement protects the chiller from the corrosive brine. The system is controlled on-off by a room thermostat in the house. The system performance is modelled by dynamic thermal simulation using TMY2 hourly typical weather data. TRNSYS software is used for the main simulation, coupled to a MATLAB model of heat and mass transfer in the pond and the ground beneath it. The model of the pond and the ground is one-dimensional (only vertical transfers are considered). Radiation, convection, conduction, evaporation and diffusion are considered; the ground water at some depth below the pond is treated as being at a fixed temperature. All input data and parameter values in the simulation are based on published, standard or manufacturer's data. Temperature profiles in the pond were calculated and found to be in good agreement with published experimental results. It was found that a pond area of approximately 400 m2 was required to provide satisfactory cooling for a non-insulated house of approximately 125 m2 floor area. It was found that varying the pond area, ground conditions and pond layer thicknesses affected the system performance. The optimum site is one that has soil with low thermal conductivity, low moisture content and a deep water table. It is concluded that Iraq's climate has a potential for solar-pond-powered thermal cooling systems. It is feasible to use a solar-pond-powered cooling system to meet the space cooling load for a single family house in the summer season. Improving the thermal performance of the house by insulation could reduce the required solar pond area.

APA, Harvard, Vancouver, ISO, and other styles

35

Drozd, Malgorzata. "Caractérisation fonctionnelle des nouveaux gènes et des voies moléculaires impliquées dans les troubles du développement du cerveau." Electronic Thesis or Diss., Université Côte d'Azur, 2020. http://theses.univ-cotedazur.fr/2020COAZ6021.

Full text

Abstract:

Les troubles du développement du cerveau (DBD) englobent un groupe très hétérogène de troubles provenant du dysfonctionnement cérébral du développement. Les DBD comprennent, entre autres, la déficience intellectuelle, certaines formes d’épilepsie, le trouble du spectre autistique (TSA), le trouble d’hyperactivité avec déficit de l’attention, les troubles de l’apprentissage et du langage et la schizophrénie. Au cours de ma thèse, j’ai participé à deux projets de recherche distincts. Le premier projet visait la caractérisation fonctionnelle de nouveaux gènes impliqués dans la schizophrénie à début précoce (SDP), le trouble du spectre autistique et la déficience intellectuelle. Au cours de cette étude, le séquençage de l’exome entier (WES) de 9 TRIOs a été effectué afin de trouver de nouveaux gènes impliqués dans la pathogenèse de la SDP. Les patients ont été diagnostiqués avec la SDP, qui dans certains cas est associée à d’autres phénotypes tels que le TSA ou la déficience intellectuelle. J’ai trouvé quelques variants très rares qui ont un impact pathologique putatif sur le phénotype des patients selon l’analyse in silico. Un variant a été identifié dans le gène Sérine/thréonine-protéine kinase 33 (STK33) qui est un membre éloigné du groupe CAMK de sérine/thréonine kinases. Les membres de cette famille participent à la régulation de l’homéostasie calcique qui s’est avérée altérée chez les patients atteints de schizophrénie. Pour évaluer l’impact pathologique de la mutation dans STK33, j’ai créé un modèle cellulaire dans la lignée cellulaire SH-SY5Y par la technique CRISPR-Cas9 imitant la variante trouvée chez le patient. Pour décrire le phénotype de la lignée cellulaire mutée, j’ai effectué l’analyse de l’expression des gènes et des protéines ainsi que des expériences d’imagerie calcique.Le deuxième projet de ma thèse a été associé à la caractérisation d’une nouvelle mutation spontanée du gène Kcc2 chez la souris souffrant de crises tonico-cloniques spontanées à partir de l’âge de quatre mois. Le gène Kcc2 code le cotransporteur neuronal du chlorure de potassium KCC2, qui participe à la sortie des ions chlorure des cellules et au maintien de l’équilibre excitation/inhibition. Nous pensons que les variants de ce gène ont un fort potentiel de causer des dysfonctionnements neurodéveloppementaux. La plupart d’entre eux sont associés à l’épilepsie de la petite enfance avec crises focales migrantes (EIMFS), qui appartient à un groupe de syndromes épileptiques rares. Nous avons développé la présente étude dans le but de caractériser le premier modèle d’épilepsie spontanée chez la souris due à une mutation du gène Kcc2 en corrélant l’activité neuronale, l’apparence des crises et le comportement social et cognitif avec l’expression génique. À ce jour, ces études fonctionnelles n’ont pas été réalisées puisque les souris Kcc2-KO meurent quelques jours après la naissance et que les animaux hétérozygotes n’ont jamais été étudiés en détail. La mutation identifiée chez nos souris affecte le même acide aminé qui a été trouvé muté chez un patient EIMFS (R857L), offrant une occasion unique d’étudier l’étiologie de l’EIMFS in vivo. Jusqu’à présent, nous avons observé que chez les souris mutantes Kcc2, la production de la protéine est fortement diminuée dans le cortex cérébral, l’hippocampe et le striatum. De plus, le cross-linking assay et l’analyse immunohistochimique ont révélé une diminution de la protéine KCC2 au niveau de la membrane. En effectuant une iEEG, il a été possible d’observer le point typique pour épilepsie chez souris mutantes Kcc2. Pour le moment, des études comportementales ont révélé que les souris Kcc2 mutantes présentaient des déficits d’apprentissage et de mémoire. Ces résultats nous ont donné une solide base pour une évaluation plus approfondie de notre modèle et une possibilité d’obtenir un meilleur aperçu de la pathogenèse des EIMFS avec le but final de définir des interventions thérapeutiques Developmental Brain Disorders (DBDs) encompass a highly heterogeneous group of disorders that manifest through cognitive, motor, neurobehavioral, neuroanatomical and neurophysiological aberrations originating from developmental brain dysfunction. DBDs include, among others, Intellectual Disability (ID), some forms of epilepsy, Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder, learning and language disorders and Schizophrenia (SCZ). During my thesis, I was involved in two distinct research projects. The first project aimed at the functional characterization of new genes implicated in Early Onset Schizophrenia (EOS), ASD and ID. During this study, Whole Exome Sequencing of 9 TRIOs (affected child and both parents) was performed in order to find new genes that are involved in the pathogenesis of EOS. Probands were diagnosed with EOS, which in some cases was combined with other phenotypes such as ASD or ID. I found some very rare variants that have a putative pathological impact on the phenotype of the patients according to in silico analysis. One variant was identified in the gene Serine/threonine-protein kinase 33 (STK33) that is a distant member of the CAMK group of serine/threonine kinases. The members of this family participate in the regulation of calcium homeostasis that was shown to be altered in patients with schizophrenia. To further evaluate the pathological impact of mutation in STK33 I created a cellular model in the SH-SY5Y cell line by the CRISPR-Cas9 technique mimicking the potential variant found in the patient. To describe the phenotype of the mutated cell line, I performed the analysis of gene and protein expression as well as calcium imaging experiments. The second project during my thesis was associated with characterization of a novel spontaneous mutation in the Kcc2 gene in mouse suffering from spontaneous tonic-clonic seizures starting at the age of four months. The Kcc2 gene codes the neuronal potassium chloride co-transporter KCC2, which participates in extrusion of chloride ions from cells, protection of neuronal networks against excitotoxicity, dendrite morphogenesis and in the maintenance of the excitation/inhibition balance. Variants in this gene are believed to have a strong potential to cause neurodevelopmental dysfunctions. Most of them are associated with Epilepsy of Infancy with Migrating Focal Seizures (EIMFS), which belongs to a group of rare epileptic syndromes. We developed the present study with the aim of characterizing the first spontaneous epilepsy model in mouse due to a mutation in the Kcc2 gene by correlating neuronal activity, seizure appearance and social and cognitive behavior with gene expression. To date these functional studies were not performed since Kcc2-KO mice die few days after birth and heterozygous animals were never studied in detail. The mutation identified in our mice affects the same amino acid that has been found mutated in an EIMFS patient (R857L), offering a unique opportunity to study the etiology of EIMFS in vivo. So far, we observed that in mutant Kcc2 mice, production of the protein is strongly decreased in brain cortex, hippocampus and striatum. Moreover, cross-linking assay and immunohistochemical analysis revealed a decrease of the KCC2 protein at the membrane level. By performing intracranial ElectroEncephaloGraphy, it was possible to observe the shape of the typical spike for epileptic mouse. For the time being, behavioral studies revealed that mutant Kcc2 mice exhibit learning and memory deficits. These findings gave us a strong background for further evaluation of our model and a possibility to get further insight into the pathogenesis of EIMFS with the final purpose to define therapeutic interventions

APA, Harvard, Vancouver, ISO, and other styles

36

Adabi, Firouzjaee Jafar. "Remediation strategies of shaft and common mode voltages in adjustable speed drive systems." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/39293/1/Jafar_Adabi_Firouzjaeel_Thesis.pdf.

Full text

Abstract:

AC motors are largely used in a wide range of modern systems, from household appliances to automated industry applications such as: ventilations systems, fans, pumps, conveyors and machine tool drives. Inverters are widely used in industrial and commercial applications due to the growing need for speed control in ASD systems. Fast switching transients and the common mode voltage, in interaction with parasitic capacitive couplings, may cause many unwanted problems in the ASD applications. These include shaft voltage and leakage currents. One of the inherent characteristics of Pulse Width Modulation (PWM) techniques is the generation of the common mode voltage, which is defined as the voltage between the electrical neutral of the inverter output and the ground. Shaft voltage can cause bearing currents when it exceeds the amount of breakdown voltage level of the thin lubricant film between the inner and outer rings of the bearing. This phenomenon is the main reason for early bearing failures. A rapid development in power switches technology has lead to a drastic decrement of switching rise and fall times. Because there is considerable capacitance between the stator windings and the frame, there can be a significant capacitive current (ground current escaping to earth through stray capacitors inside a motor) if the common mode voltage has high frequency components. This current leads to noises and Electromagnetic Interferences (EMI) issues in motor drive systems. These problems have been dealt with using a variety of methods which have been reported in the literature. However, cost and maintenance issues have prevented these methods from being widely accepted. Extra cost or rating of the inverter switches is usually the price to pay for such approaches. Thus, the determination of cost-effective techniques for shaft and common mode voltage reduction in ASD systems, with the focus on the first step of the design process, is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. Electrical power generation from renewable energy sources, such as wind energy systems, has become a crucial issue because of environmental problems and a predicted future shortage of traditional energy sources. Thus, Chapter 2 focuses on the shaft voltage analysis of stator-fed induction generators (IG) and Doubly Fed Induction Generators DFIGs in wind turbine applications. This shaft voltage analysis includes: topologies, high frequency modelling, calculation and mitigation techniques. A back-to-back AC-DC-AC converter is investigated in terms of shaft voltage generation in a DFIG. Different topologies of LC filter placement are analysed in an effort to eliminate the shaft voltage. Different capacitive couplings exist in the motor/generator structure and any change in design parameters affects the capacitive couplings. Thus, an appropriate design for AC motors should lead to the smallest possible shaft voltage. Calculation of the shaft voltage based on different capacitive couplings, and an investigation of the effects of different design parameters are discussed in Chapter 3. This is achieved through 2-D and 3-D finite element simulation and experimental analysis. End-winding parameters of the motor are also effective factors in the calculation of the shaft voltage and have not been taken into account in previous reported studies. Calculation of the end-winding capacitances is rather complex because of the diversity of end winding shapes and the complexity of their geometry. A comprehensive analysis of these capacitances has been carried out with 3-D finite element simulations and experimental studies to determine their effective design parameters. These are documented in Chapter 4. Results of this analysis show that, by choosing appropriate design parameters, it is possible to decrease the shaft voltage and resultant bearing current in the primary stage of generator/motor design without using any additional active and passive filter-based techniques. The common mode voltage is defined by a switching pattern and, by using the appropriate pattern; the common mode voltage level can be controlled. Therefore, any PWM pattern which eliminates or minimizes the common mode voltage will be an effective shaft voltage reduction technique. Thus, common mode voltage reduction of a three-phase AC motor supplied with a single-phase diode rectifier is the focus of Chapter 5. The proposed strategy is mainly based on proper utilization of the zero vectors. Multilevel inverters are also used in ASD systems which have more voltage levels and switching states, and can provide more possibilities to reduce common mode voltage. A description of common mode voltage of multilevel inverters is investigated in Chapter 6. Chapter 7 investigates the elimination techniques of the shaft voltage in a DFIG based on the methods presented in the literature by the use of simulation results. However, it could be shown that every solution to reduce the shaft voltage in DFIG systems has its own characteristics, and these have to be taken into account in determining the most effective strategy. Calculation of the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions is discussed in Chapter 8. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

APA, Harvard, Vancouver, ISO, and other styles

37

Chuang, Tzu-Yi, and 莊姿怡. "Investigation the Sources of Abnormal LDH Cytotoxicity Response at the Extracts of High Alkali Ash Wastes." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/65285585339367225384.

Full text

Abstract:

碩士 國立屏東科技大學 環境工程與科學系所 99 In the present study, Vero cell line was used in order to evaluate the Cytotoxicity effects of high alkaline ash extracts. lactate dehydrogenase (LDH) assay, MTT assay, and flow cytometry were used to investigate the sources of abnormal LDH response (REP%> 100, REP% &lt;0) using extracts of such kind of ash wastes. The results showed that the ion concentrations of the ash extracts were too high, resulting in a large number of cell death caused by the exposure of the cells to the different waste extracts. Non-spontaneous release of LDH caused the experimental value of the waste extracts to be lower than the control. Because negative values of REP% were obtained, the samples were diluted in a ratio of 1:9 (Sample:medium) to determined the cytotoxicity of Vero cells. In Day1the cytotoxicity had a positive value, however it then changed to a negative value and finally became positive again. We think that this phenomenon might be caused by the high amount of alkali metals and alkaline earth metal leaching within Day1 and Day2, resulting in the necrosis of some cells. The negative values on Day 3might have been due to the heavy metal leaching which cause cell cycle arrest or apoptosis.

APA, Harvard, Vancouver, ISO, and other styles

38

Toy, Brian. "Utilization of Pacific hake offal meals of different ash content as protein sources for shinook salmon in sea water." Thesis, 1992. http://hdl.handle.net/2429/3123.

Full text

Abstract:

Present demands for fish meal by the aquaculture industry in British Columbia exceed domestic supplies. The development of fisheries and onshore processing for domestically underutilized fish species have been identified as means of increasing the supply of fish waste for reduction into fish meal (DPA Group, 1988; Silver and Macleod, 1991). Pacific hake (Merluccius productus), with its large biomass and recent changes in quota allocations, is considered the most promising species for domestic exploitation (Silver and Macleod, 1991; Simpson, 1992). The following study was conducted to a) identify what impact high levels of ash in hake offal press cake meal would have on growth and various physiological parameters, and b) to compare press cake meals produced from non-deboned and deboned roe herring (Culpea harengus) and hake offals as protein sources for sea water-adapted chinook salmon (Oncorhynchus tshawytscha). In Experiment 1, chinook salmon from the Robertson Creek strain were fed to satiation on diets containing either 13.4, 18.1, or 23.1% ash. Hake offal press cake meal was the sole protein source and all diets were formulated to be isonitrogenous (protein = 48%) and isocaloric (37.4 kcal of estimated metabolizable energy/kg dry diet). During the 42-day trial, there were no significant differences in fish growth, appetite or feed efficiency. The concentrations of supplementary minerals in the diet were sufficient to maintain normal growth and development in the fish. Dietary ash levels had no impact on the terminal plasma concentrations of calcitonin or teleocalcin, gastrointestinal pH values, or gross morphology. Attempts to correlate hormonal levels to the amounts of feed in the gastrointestinal tract were unsuccessful. Elevated levels of calcitonin seemed to be related to the maturation state of some of the fish. In Experiment 2, chinook salmon in sea water were fed to satiation on diets containing press cake meals made from deboned or non-deboned hake offal or roe herring. The diets were formulated to be isocaloric (36.8 kcal of estimated metabolizable energy/ kg dry diet) and to contain either 35 or 48% protein which originated solely from one of the four test meals. A high protein diet (48% protein) based on freeze dried hake fillets was used as a positive control. High protein diets supported better growth and feed consumption than the low protein diets. By the end of the experiment, fish fed the low protein diets had higher percentages of carcass lipid and correspondingly lower percentages of carcass protein than fish fed the high protein diets. Feeding behavior differed between fish consuming the low and high protein diets. In the former case, the fish would stop feeding sooner and would actively pursue, capture, and mouth the pellets before expelling them. Very little of the mouthing behavior was displayed by fish on the high protein diets.. Amongst the fish fed the high protein diets, deboning of roe herring offal tended to improve growth, feed consumption, feed efficiency, protein efficiency ratio, body protein content, productive protein value, instantaneous protein gain, and instantaneous lipid gain, whereas the opposite was true for those receiving the deboned hake offal. Examination of the performance data suggested that the amount and availability of dietary arginine, rather than the level of ash, was the limiting factor for growth of fish receiving diets based on deboned hake offal. Fish fed the low protein diets containing deboned hake or herring meal exhibited different trends of performance to those described above for fish ingesting the high protein diets. In this case, deboning had no effect on the performance of chinook salmon fed the hake meal or herring meal diets. Despite the concentrations of arginine in the low protein hake meal diets not meeting estimated requirements and the arginine concentrations in the herring meal diets meeting the requirements, the fish consuming the hake diets tended to have the better growth performance and feed efficiency. However, the trend was not supported by the productive protein value. It can be concluded, therefore, that for the fish eating the low protein diets the hake and herring offal meals were of equal nutritional value. This study indicates that deboning the hake offal was unnecessary and that chinook salmon seemed to be able to utilize hake offal press cake meal as effectively as the herring offal press cake meal.

APA, Harvard, Vancouver, ISO, and other styles

39

Huang, Jiann Hung, and 黃建宏. "Comparision of various properties of monoliths solidified from municipal incinerator fly ash of different sources and pretreatments by high temperature burning and water washing." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/02619419591589424275.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

TOURNIGAND, PIERRE-YVES. "Transient volcanic ash plumes: Morpho-dynamical evolution and source properties." Doctoral thesis, 2018. http://hdl.handle.net/11573/1075234.

Full text

Abstract:

Transient volcanic plumes, typically generated by Strombolian and Vulcanian eruptions, are time-dependent features characterized by rise and development time scales similar to the eruption duration. Their morphological and dynamical properties are thus strongly related to the source conditions and evolution over time, i.e. (ejection duration, spatial spreading, ejection angle, time interval between pulses). In this study, the shape evolution and dynamics of initial transient volcanic plumes development, as well as their relation with discharge history, have been investigated using high-speed and high-resolution visible-light and thermal infrared videos. Physical parameterization of the plumes has been performed by defining their front velocity, volume and apparent surface temperature. Optical flow computer vision tool and fractal dimension analysis were applied for the first time in order to extract plume velocity field and shape complexity evolution over time, respectively. The source conditions were characterized both qualitatively, in terms of number, location, duration, and frequency of individual ejection pulses, and quantitatively, in terms of time-resolved ash eruption rate and a newly-defined instability factor. The newly proposed, image-based method I developed to retrieve discharge rate provides results that are comparable with previous methods but with more than one order of magnitude increase in time resolution. Results show that the connection between source properties and the dynamical and morphological features of transient plumes holds true for every one of our study cases, which encompass a variety of eruption styles and plume heights and shapes. In particular, plume front velocity, temperature decay, and plume complexity, as measured by fractal dimension, all follow complex evolutions which are intimately linked with the discharge history at the vent. Of the different factors that characterize vent discharge, lateral shifts in the ejection (from, e.g., vent shifts or changes in vent geometry or angle of the ejection) and temporal fluctuations, including the tempo and intensity of ejection pulses and other changes in the discharge rate, exert the strongest controls on plume evolution. These lateral and temporal changes at the vent can be combined in a general source instability factor that, by controlling the formation of the vortexes at the base of the plume, eventually determines the modes of air entrainment and the overall evolution of the plume. The connection between source instability and plume dynamics that I quantified in this study brings new understandings on the formation and initial development of unsteady volcanic plumes. Settings of new characterization tools such as fractal analysis and time-dependent discharge rate show promising results and potential for new monitoring resources.

APA, Harvard, Vancouver, ISO, and other styles

41

Lu, Yen-Hung, and 盧彥宏. "Design and Improvement of Uncooled ASE Fiber Sources." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94536179763654307316.

Full text

Abstract:

碩士 國立臺灣科技大學 電子工程系 101 Some schemes for superfluorescence fiber sources are proposed in the thesis. We investigated and measured the effect of the output characteristic and mean wavelength for superfluorescence fiber sources, which were integrated by using such as broadband fiber Bragg grating (BBFBG), erbium doped fiber (EDF) and so on. To achieve the National Space Organization (NSPO) regulation for thermal stability of mean wavelength of 2.5 ppm/oC, the fiber optic gyroscope (FOG) light source in double-pass forward pumping scheme was proposed using BBFBG. But the experimental result shows that the thermal stability for mean wavelength superfluorescence fiber source still leaves room for improvement. Therefore, Carbon fiber composites glued upon BBFBG is used in Chapter 3. Later, we studied the optimum angle condition for carbon fiber composites between the adjacent layers to improve the thermal stability of mean wavelength for the proposed superfluorescence fiber source. 　　Then, some configurations design for SFS with residual pumping power. Both double-pass forward pumping scheme and double-pass backward pumping scheme were discussed in Chapter 4. Three optional reflectors could be chosed, one is a broadband fiber mirror, another is a Sagnac Loop and the other is an optical circulator. The experimental results show that double-pass backward pumping scheme using an optical circulator as a reflector has excellent output characteristic among the three kinds of reflectors. But after the thermal stability of mean wavelength measurement, this thermal stability of mean wavelength is still a little bit higher than the target value. It is because that 1530 nm amplified spontaneous emission (ASE) in superfluorescence fiber source may degrade the average thermal stability of mean wavelength. In fortune, this issue was solved by using a piece of absorber and adopted a double-pass backward pumping scheme. Results shows that after we suppressed the 1530 nm ASE, the thermal stability of mean wavelength could be further improved successfully to 1.3 ppm/oC.

APA, Harvard, Vancouver, ISO, and other styles

42

Cheng, Chun-ho, and 鄭群禾. "Utilizing Rice Husk Ash as Silicon Source to Synthesize Type A Zeolite." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/68979166054335622422.

Full text

Abstract:

碩士 國立臺灣科技大學 化學工程系 102 Taiwan produces about 300,000 tons of rice husk per year. Rice husk can be burned to supply heat. The ash from the burning contains significant amount of silica which makes the ash a valuable resource. Nevertheless, resource is often wasted by burying in the field. The purpose of this research is to develop a way of utilizing the rice husk ash (RHA) by extracting the silica from it and used silica to synthesize type-A zeolite. Type-A zeolite has the highest ion-exchange capability among zeolites, and is also remarkable in capability in absorbing moisture. The greatest applications of type A zeolite is to use as an additive in detergent and as a drying reagent. The cation-exchange capability of type-A zeolite makes it especially suitable to solve environmental problems, such as removing harmful cations, including radio active cations, from waste water. The contents of this studied can be classified into three parts, namely extracting silica from RHA and building a mathematical model for it, utilizing the extracted silica to synthesize type-A zeolite and examining the process of the synthesis, and finally, comparing the differences among the zeolites synthesized from different silicon sources (RHA, sodium silicate, and TEOS). An extraction model based on shrinking core, first order reaction and second order reactivity decay was developed. The model can precisely predict the fraction of silica in RHA extracted with respect to extraction time and temperature. The maximum crystallinity of the zeolite synthesized from RHA was found to be 80%. The crystallization process could be divided into three periods, the induction, the transition, and the crystal growth periods. A mathematical model was developed to describe the relation between the crystallinity and synthesis time at varied temperature. This study revealed that moisture absorbing capability of the RHA-zeolite increased linearly with the crystallinity of the zeolites. Under the condition of 49-64% relative humidity, the rate and maximum of moisture absorption was not affected by the moisture. The maximum amount of moisture a RHA-zeolite could absorbed was about 21% of the weight of the zeolite, and it took about 40 minutes to reach the maximum under 49% relative humidity. Other than RHA, this investigation also used TEOS and sodium silicate to synthesize type-A zeolite. The resulting zeolites were compared. The crystallinity of the zeolites synthesized from varied silicon source was found to be 81.7% (RHA), 78.6% (sodium silicate) and 26.5% (TEOS). In addition, the RHA-zeolite was found to contain 11.5% impurities, while the other two zeolites had none. The ion-exchange capability of RHA-zeolite was about the same as that of sodium-silicate-zeolite, and was far greater than that of TEOS-zeolite. The size of the RHA-zeolite was found to be 2.3 nm which was about 3 times larger than that of sodium-silicate-zeolite.

APA, Harvard, Vancouver, ISO, and other styles

43

Li, Ti-Chun, and 李梯群. "Effect of Coal Fly Ash Source on the Properties of GBFS/FA-Based Geopolymer Mortar." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/pmz9xa.

Full text

Abstract:

碩士 國立臺北科技大學 資源工程研究所 106 Global warming is a controversial problem worldwide and the cement industry’s annual carbon dioxide emissions account for 5%–7% of the world’s emissions. Therefore, to solve this problem, discovering an alternative material to replace cement is vital. Numerous studies have considered geopolymer as a material that can replace cement in the future because it has excellent mechanical properties. Many resources exist that are rich in silicon and aluminum and can therefore be used as raw material. However, the same type of raw materials from different sources may cause the mechanical properties of geopolymer to differ. Thus, the present study investigated the performance of a geopolymer that was manufactured using coal fly ash from different sources. First, geopolymer paste was produced from different sources of coal fly ash (Linkou, Xingda, and Dalin Power Plants), and the difference between workability and mechanical strength in each series was discussed. Second, we used different sources of coal fly ash and added an aggregate to manufacture a geopolymer mortar that could reduce the effects of IV environmental factors, and then we changed the parameter of the alkali solution (SiO2/Na2O molar ratio and SiO2/Al2O3 molar ratio) to explore the mortar’s influence on workability and its mechanical properties. Finally, we comprehensively discussed workability, mechanical strength, durability, and structural differences in different sources of geopolymer, and investigated the effect of different factors on the main properties through variance analysis. The results indicated that the smaller the particle size of coal fly ash with a short hardening time, the faster the dehydration speed and greater the strength compared with time. The higher the amorphous value of the different sources of fly ash, the greater the reactivity and higher the mechanical strength. In addition, the change in the SiO2/Na2O molar ratio had little effect on the mechanical properties of the alkali solution. Regarding the change of SiO2/Na2O molar ratio, adding the A1 source yielded a longer hardening time of the geopolymer mortar, but the strength and durability of the mortar were greater than those that the Al source were not added to. In terms of structure, it can be observed from FT-IR that the geopolymer produced by different coal fly ash samples had a characteristic shift of Si-O to the position of Si-OT compared with the peak of the raw material. The characteristics that were more obvious denoted that the structure of the geopolymer was produced. According to the variation analysis, the SiO2/Al2O3 molar ratio of the alkali solution was the main influencing factor of hardening time and durability, and the different sources of fly ash were due to the different amorphous values, which affected the compressive strength of the geopolymer mortar.

APA, Harvard, Vancouver, ISO, and other styles

44

Nagar, Rahul. "Preparation of diopside by novel sol-gel method using rice husk ash as silica source." Thesis, 2011. http://ethesis.nitrkl.ac.in/2165/1/Rahul_Nagar.pdf.

Full text

Abstract:

Diopside (CaMgSi2O6) was synthesised through a novel sol-gel synthesis. Sol-gel synthesis usually utilises silicon alkoxides (e.g TEOS) for the synthesis of Diopside. The material is costly and unstable in the air atmosphere. In the present investigation, rice husk ash (RHS) has been used for an alternative to TEOS raw material. RHS is cheap and contains amorphous silica which can be dissolved in the solution. RHS was dissolved in citric acid and metal nitrate solution. The gelling was performed. The gel was characterised for TG-DSC analysis. The phase formation behaviour with the application of heat on the gel was studied by calcining it at different temperatures upto 1050oC. XRD phase analysis showed the formation of diopside phase in the calcined product. The material was sintered at 1100oC and tested for bio-activity by incubating in SBF solution. The material induces apatite formation in its surface within 14 days of incubation. In conclusion, the Diopside bioactive material synthesised through this novel sol-gel processing, may be a cost effective material for bulk applications.

APA, Harvard, Vancouver, ISO, and other styles

45

Chu, Chao-Yi, and 朱肇易. "Remotely Pumped WDM PON Systems using ASE Sources for Bidirectional Transmission." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/05966783618021948225.

Full text

Abstract:

碩士 國立臺灣科技大學 電子工程系 101 We propose and experimentally demonstrate the design of a remotely pumped WDM-PON architecture to provide 2.5-Gb/s bidirectional transmission with potential low-cost configuration. In this scheme, we use amplified spontaneous emission (ASE) light source with broad optical spectrum for downstream and upstream transmission. The ASE light source spectrum is sliced by the arrayed waveguide grating (AWG) at the central office (CO) and remote node (RN) and each spectrum slice is used to carrier the signal of a downstream or upstream channel. A reflected electro-absorption modulator (REAM) is used to encode the upstream signals and achieve colorless operation. An electro-absorption modulator (EAM) is used to encode the downstream signals. In order to achieve a transmission up to 25 km distance, a low-dispersion fiber like a larger effective area fiber (LEAF) is used to reduce the dispersion effect. Due to the low power density of ASE source and the insertion loss caused by passive components and modulation, a remotely pumped erbium-doped fiber amplifier (RP-EDFA) is employed to provide extra gain to both downstream signals and upstream signals. The RP-EDFA can compensate the propagation loss and spectral slicing loss. The experimental results show that the downstream and upstream transmission of 2.5Gb/s data rate for each 8 channels can achieve a bit error rate (BER) of lower than 10-9 over 25 km of distance.

APA, Harvard, Vancouver, ISO, and other styles

46

Lin, Chang-Yu, and 林昶佑. "WDM-PON Systems Based on ASE Sources and Remotely Pumped EDFAs." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36153747179354482137.

Full text

Abstract:

碩士 國立臺灣科技大學 電子工程系 101 We have proposed and experimentally demonstrated a novel remotely pumped WDM-PON architecture to provide 10/1.25-Gb/s bidirectional transmission with potential low-cost configuration. In this scheme, we use amplified spontaneous emission (ASE) light source with broad optical spectrum for upstream transmission. The ASE light source spectrum is sliced by the arrayed waveguide grating (AWG) at the remote node (RN). A reflected electro-absorption modulator (REAM) is used to encode the upstream signals and achieve colorless operation. For downstream transmission a laser diode is used as the upstream light source. In order to achieve 10 Gb/s transmission data rate, we use external Mach-Zehnder modulator to carry the downstream data. The remotely pumping scheme can compensate the double-pass optical loss and enhance the signal to noise ratio. The remotely pumped architecture may give nonuniform gain for different wavelength channels. In order to provide fair performance to all the channels, a slanted gain flattening filter (GFF) was added to improve the power nonuniformity for the upstream signals.

APA, Harvard, Vancouver, ISO, and other styles

47

Cheng, Yen-Hui, and 陳炎輝. "Fabrication 1480nm Pumping Sources and Effect of ASE Optical Spectrum in Different Temperatures." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/71014424575299622758.

Full text

Abstract:

碩士 逢甲大學 電機工程所 94 The research is mainly to achieve an ASE light source with a 1480nm pumping laser. The constant electric current-driving IC circuits are used for providing a stably electric current source to pump the laser and a temperature-controlled IC circuits are used for controlling the laser temperature accurately. The 1480nm pumping laser sources are launched into two different erbium-doped concentration fibers of 8 meters length and then put the erbium-doped fibers into a heater for observing the variation of ASE optical spectra respectively. It will affect the distribution among multiple location steps in the erbium ion when temperature changed which cause absorptive area and emissive area to change, making average-wavelength shift of ASE sources.

APA, Harvard, Vancouver, ISO, and other styles

48

Hung, Hung-Wen, and 洪鴻文. "10-Gb/s Bidirectional WDM-PON Transmission Using Spectrum-sliced ASE Light Sources." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/46684571808470449827.

Full text

Abstract:

博士 國立臺灣科技大學 電子工程系 104 We propose and demonstrate a remotely pumped WDM-PON architecture to achieve 10 Gb/s symmetrical bandwidth for bidirectional transmission. In this scheme, a wideband amplified spontaneous emission (ASE) from an optical amplifier is sliced into multiple channels by an arrayed waveguide grating (AWG) and used as multi-channel optical sources for WDM-PON system. Each channel is noise suppressed by using a gain-saturated cascaded semiconductor optical amplifer (SOA) and then modulated at 10.7 Gb/s of nonreturn-to-zero (NRZ) signals by using electrochromic absorption modulator (EAM), assuming forward error correction (FEC) with 7% overheads for improving the bit error rate (BER) of system. We also propose a redband-seeding scheme to provide uplink seeding light and use a reflected electro-absorption modulator (REAM) to encode the upstream signals. In order to achieve a transmission up to 25 km distance, we use a larger effective area fiber (LEAF) to reduce the dispersion effect. To compensate the loss by passive components and modulation, we employ a remotely pumped erbium-doped fiber amplifier (RP-EDFA) to provide extra gain for both downstream and upstream signals. The experimental results show that the downstream and upstream transmission can provide 10 Gb/s data rate over 25 km for 32 channels, which corresponds to a total capacity of 320 Gb/s, on each direction.

APA, Harvard, Vancouver, ISO, and other styles

49

Pierce, John Donald. "U-Pb geochronology of the Late Cretaceous Eagle Ford Shale, Texas; defining chronostratigraphic boundaries and volcanic ash source." Thesis, 2014. http://hdl.handle.net/2152/26920.

Full text

Abstract:

The Eagle Ford Shale and equivalent Boquillas Formation (Late Cretaceous) contain abundant volcanic ash beds of varying thickness. These ash beds represent a unique facies that displays a range of sedimentary structures, bed continuity, and diagenetic alteration. They are prominent not only in West Texas outcrops, but also in the subsurface of South Texas where hydrocarbon production is actively occurring. The ash beds have the potential to be used for stratigraphic correlation for understanding early diagenesis and — most importantly — for obtaining high-resolution geochronology, which can then be used for defining depositional rates and chronostratigraphy. Study of the ash beds was conducted at outcrops along U.S. 90, west of Comstock, Texas, the subsurface in Atascosa and Karnes County, and at a construction site in South Austin. Bed thicknesses range from 0.1–33 cm and were collected throughout the entirety of the Eagle Ford succession. Mineral separation yielded abundant non-detrital zircons for U-Pb dating. Dating was conducted using LA-ICP-MS at The University of Texas at Austin, to attain a base level understanding of the age range for the Eagle Ford. High-resolution ages for the base and top of the Eagle Ford were obtained, in addition to radioisotopically defining the Cenomanian-Turonian boundary within the section. U-Pb ages for the Eagle Ford Shale range from Early Cenomanian to Late-Coniacian near Comstock, Mid-Cenomanian to the Turonian-Coniacian boundary in the subsurface, and Early Cenomanian to Late Turonian in Austin area. These findings contrast with many of the regional biostratigraphic studies across the Eagle Ford and indicate a more prolonged period of Eagle Ford deposition than previously observed. text

APA, Harvard, Vancouver, ISO, and other styles

50

Duh, Jing-Min, and 杜敬民. "Evaluation of the PCDD/Fs Discharge from Wastewater and Source Apportionment of Illegally Dumped Fly Ash in Taiwan." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/89515433539611646786.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Sources of ash'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles