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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

A Nonintrusive Diagnostics Technique For Flame Soot Based On Near-infrared Emission Spectrometry

Ayranci Kilinc, Isil 01 June 2007 (has links) (PDF)
A novel nonintrusive soot diagnostics methodology was developed, validated and applied for in-situ determination of temperature, volume fraction and refractive index of soot aggregates formed inside flames by using near-infrared emission spectrometry. Research was conducted in three main parts, first one addressing development and validation of a comprehensive &quot / direct&quot / model for simulation of line-of-sight radiative emission from axisymmetric sooty flames by coupling sub-models for radiative transfer, radiative properties and optical constants. Radiative property estimation for soot agglomerates was investigated by experimentally validating discrete dipole approximation against microwave measurements and using it as reference to assess applicability of simpler Rayleigh-Debye-Gans approximation for fractal aggregates (RDG-FA). Comparisons between predictions of two methods for soot-like model aggregates demonstrated that radiative property predictions of RDG-FA are acceptably accurate for relatively small soot aggregates encountered in small-scale flames. Part two concerns experimental investigation of an axisymmetric ethylene/air diffusion flame by Fourier Transform Near-Infrared spectroscopy. Measurement of line-of-sight emission intensity spectra was performed along with analyses on calibration, noise, uncertainty and reproducibility. A noise characterization approach was introduced to account for spatial fluctuations which were found to dominate over spectral noise. Final part focuses on development, evaluation and application of an inversion methodology that inputs spectral emission intensity measurements from optically thin flames, removes noise, identifies soot refractive index from spectral gradients and retrieves soot temperature and volume fraction fields by tomographic reconstruction. Validation with simulated data and favorable application to measurements indicate that proposed methodology is a promising option for nonintrusive soot diagnostics in flames.
12

Synthesis And Characterization Of Novel Rare Earth Phosphates And Rietveld Structural Analysis Of Rare Earth Orthoborates

Seyyidoglu, Semih 01 October 2010 (has links) (PDF)
This thesis covers the synthesis and the characterization of sodium lanthanide oxide phosphates, rare earth added strontium pyrophosphates and the Rietveld structural analysis of rare earth orthoborates. Solid state and microwave-assisted synthesis method was employed for the synthesis of desired materials. The formation of the produced phases was confirmed by X-ray Diffraction (XRD), Infrared FT-IR, Raman, Scanning Electron Microscopy (SEM) methods. By using Rietveld Refinement method, structural analysis of rare earth orthoborates were done and three dimensional crystal structures were found. In the first part of the thesis, some new sodium lanthanide oxide phosphates were synthesized by solid state reaction method from Ln2O3 (where Ln= La, Nd, Sm, Gd, Dy, Ho, Er, Yb), Na2CO3, NH4H2PO4 at 1100 oC. Na2LaOPO4, Na2NdOPO4, and Na2SmOPO4 produced with the space group is Pmm2. With the help of the same procedure new orthorhombic Na2DyOPO4, Na2HoOPO4, Na2ErOPO4, and Na2YbOPO4 were synthesized for the first time in the literature at 1100 oC with the same space group Pmm2. v In the second part of the thesis, Sr2P2O7 - ZrP2O7 solid solution was obtained by the solid state reaction and they were characterized for the first time in literature and subjected to thermoluminescence measurements showing Sr2P2O7 has glow curve around 100 oC. Then CuO and some rare earth oxides (Y2O3, La2O3, CeO2, Pr6O11, Nd2O3, Sm2O3, Eu2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3) 0.5-15% (by weight) were added to pure Sr2P2O7. After structural determinations by XRD, thermoluminescence studies showed two glow peaks of Pr, Ho, and Nd along with Cu-added samples, one of them is always at around 90 oC and the other TLthermoluminescence- peak around 180, 275, and 285 oC, respectively. This study showed that rare earth added Sr2P2O7 materials can be promising material for dosimetric applications. In the third part of this work, time saving microwave-assisted synthesis method was applied to produce pure LnBO3 (Ln=La, Nd, Dy, Ho) by using urea and sucrose as a microwave active organic additive. For LaBO3 and NdBO3, space group found as Pnma and for DyBO3 and HoBO3 powders crystallized in hexagonal unit cell with P-6c2 space group. All microwave-assisted products have particle sizes lower than 1 micrometer. In the final part of this study, pure LnBO3 (Ln=Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu) powder samples were produced by using solid state reactions of Ln2O3 and H3BO3 (ratio=1:2) heated at 900 oC for 10 hours and 1000 oC for 5 hours. The crystallographic studies conducted with rietveld structural refinement and unit cell parameters, background functions, profile parameters, zero shift, atomic positions, and unisotropic thermal parameters were refined. LaBO3 and NdBO3 were solved based on Pnma orthorhombic structure while the crystal structure of YBO3, DyBO3 and HoBO3 were monoclinic C2/c. SmBO3 showed triclinic P-1 structure.
13

Temperature Estimation Studies On Infrared Images Using Radiometric Approaches

Atay, Yagmur 01 September 2011 (has links) (PDF)
In this thesis work, temperature estimation algorithms based on physical and radiometric approaches are developed. Developed algorithms, firstly, tested on artificial images for different test cases. Following this, algorithms are tried out on real infrared images in order to verify that they are working properly. Finally, temperature estimations are done by including emissivity. Obtained results are compared to the temperature estimation results of a reference infrared camera. All the results and errors obtained during this study are presented and discussed.
14

Theodore Ziolkowski, Clio the romantic muse : historizing the faculties in Germany, Ithaca 2004 (Rezension)

Schneider, Ulrich Johannes 09 October 2014 (has links) (PDF)
Zu bewundern ist an diesem Buch der detailreiche Überblick, die synthetische Kraft der Nacherzählung einer wichtigen Episode deutscher Geistesgeschichte. Die Aufbruchstimmung während und nach der Napoleonischen Besatzung wird plastisch an einigen Protagonisten verdeutlicht, die in Philosophie, Theologie und Historie wirkmächtig gelehrt und geschrieben haben. Wer für Hegel, Schleiermacher und Niebuhr einen gemeinsamen zeitgenössischen Kontext sucht, kann keine bessere Auskunft erhalten als in dieser spannend erzählten Studie über das romantische Denken in Deutschland.
15

Investigating The Extrusion Of Alumina Silicate Pastes For Synthesis Of Monolith Zeolite A

Ozcan, Aysenur 01 August 2005 (has links) (PDF)
Zeolites are highly porous materials that are most commonly used in granular or beaded forms. In general, zeolite granules, beads or monoliths are manufactured by using an inorganic binder which helps to cement zeolite crystals together. However, this inorganic binder decreases the purity of the zeolite structures and accessibility to the zeolite pores. A new and relatively easy method was offered for the production of binderless zeolite A tubes and bars from amorphous alumina silicate extrudates in this study. Amorphous alumina silicate powder, which is obtained by filtering the homogenous hydrogel with a composition of 2.5Na2O:1Al2O3:1.7SiO2:150H2O, is mixed with an organic binder (HEC-Hydroxyethyl Cellulose) to obtain the paste. The paste is then extruded through a die of a home-made extruder into bars and tubes. These extrudates were dried at room temperature for 24 hours, then calcined at 600oC for 2 hours and finally synthesized at 80oC for 72 hours in hydrothermal conditions to convert amorphous alumina silicate to zeolite. The most appropriate amorphous alumina silicate powder (A) / 4wt% HEC solution (H) ratio to prepare paste, hence to prepare bars and tubes was found as 0.82. The crystallinity of bars and tubes was 91% and 97%, respectively, and zeolite A was the only crystalline material. The bars and tubes were composed of highly intergrown zeolite A crystals with high porosity. Porosity of the bars is approximately 39% and porosity of the tubes is 29%, with a narrow pore size distribution. Bars have macropores of 2 &amp / #956 / m, while the macropores of the tubes are 3-4 &amp / #956 / m. The BET surface area of the bars was 411 m2/g and of tubes was 439 m2/g, which are comparable with the commercial zeolite A beads. Bars had a crushing strength of 0.42 MPa, which is sufficiently high to handle. In conclusion, zeolite A bars and tubes, with their high purity, macroporous structure and high mechanical strength, can be used in adsorption and ion exchange processes. The developed synthesis method can be scaled up to prepare honeycomb monoliths that provide higher surface are per unit volume with an appropriate extruder die.
16

Historiografía como construcción translatológica y transversal en la novela latinoamericana y española contemporánea: (A. Roa Bastos, C. Fuentes, M. Vargas Llosa y A. Gala)

de Toro, Alfonso January 2007 (has links)
El tema a tratar, la relación entre el discurso historiográfico y la realidad, por una parte, y la nueva novela histórica y la ficción, por otra, tiene tanto en la literatura como en las ciencias literarias y culturales un carácter tópico. Diversos autores, desde Aristóteles, Cervantes y Diderot hasta Balzac y Flaubert, Borges, Robbe-Grillet y Calvino se han ocupado reiteradamente con el, al parecer, siempre actualísimo fenómeno de la relación entre ficción y realidad.:Introducción al problema. - Las tesis principales de la "nueva historiografía" y "metahistoriografía". - La reelaboración de la historia: historia como construcción semióticopragmática y estrategia de hibridización. - Resumen
17

A Fast Model For Computing Infrared Atmospheric Background Effects

Sivasligil, Mustafa 01 January 2006 (has links) (PDF)
The infrared atmospheric background modeling can be considered as one of the important key factor to develop a successful target detection technique. During the infrared atmospheric background modeling, defining the input parameters of the atmospheric profile are very important for the calculations of the absorption, emission and scattering effects of the atmosphere. The main objective of this thesis is to find the answer for the question &ldquo / is it possible to determine the &ldquo / effective&rdquo / height range for the sea level midlatitude clear weather conditions in the three special wavelength bands, 1-3 &amp / #61549 / m, 3-5 &amp / #61549 / m, 8-12 &amp / #61549 / m ?&rdquo / . The answer is important for three cases. These are to overcome the difficulties of finding all the parameters of the new atmospheric profile, to determine the dominant height range for the midlatitude region, and to shorten the time of the calculations of infrared background processes. In this study, it has been shown that it should be possible to determine the effective height range for sea level midlatitude clear weather conditions in the three special wavelength bands. As a result of this study it is shown that a new atmosphere model can be constructed more easily by overcoming the difficulties of finding all the parameters of the new atmospheric profile for the sea level clear weather midlatitude regions in a short time respectively. In this study the infrared radiation flux below 5 % difference between the whole, 100 km, and the effective height ranges is accepted.
18

Análisis de las variables que influyen en el comportamiento de compra del consumidor de la empresa Tai Loy Chiclayo

Moreno Quilcate, Cesar Enrique January 2020 (has links)
El análisis del comportamiento del consumidor, específicamente las variables que influyen en este, es un tema de gran interés para toda organización, ya que en la comprensión del consumidor radica el éxito de la empresa. De tal manera, el presente trabajo de investigación tiene como objetivo general diagnosticar las variables que influyen en el comportamiento de compra del consumidor de la empresa Tai Loy Chiclayo. Además de ello tendrá como población a los consumidores de dicha empresa, donde la técnica para la recolección de datos que se utilizó en la presente investigación fue la encuesta y el instrumento de recolección fue el cuestionario el cual fue dirigido a 384 personas de la población de cinco distritos de la provincia de Chiclayo tales como Chiclayo, Pomalca, Pimentel, José Leonardo Ortiz y La Victoria para una mejor información sobre la población encuestada. Se concluyó que la variable más influyente es la variable interna, pues genera motivación, deseos, percepciones y aprendizajes en el consumidor, por lo tanto, la empresa Tai Loy debería seguir mejorando en diversos aspectos de dicha variable ya que le permitirá captar a más consumidores y que estos se fidelicen con la empresa.
19

Investigation of the production and isolation of bioactive compounds from cyanobacteria

Hameed, Shaista January 2013 (has links)
Due to heavy nutrient load and adverse climate change the occurrence of toxic cyanobacterial blooms have significantly increased during the last decades. Nodularia spumigena is one of the dominant toxic cyanobacteria which produces massive and inherent blooms in brackish water body, the Baltic Sea, particularly in late summer. Nodularia spp. are known to produce nodularins (NOD) and a range of other bioactive peptides such as spumigins and nodulopeptins, all of which have unclear function. In a recent study, three new nodulopeptins with molecular weight of 899, 901 and 917 were characterised from N. spumigena KAC 66. In the present study, N. spumigena KAC 66 was fractionated by reversed phase flash chromatography and their toxicity was determined by their lethality to Daphnia pulex and D. magna along with inhibition of protein phosphatase 1 assay (PP1). All fractions showed lethality to Daphnids and inhibitory activity against PP1, the toxicity was due to additional compounds as NOD and nodulopeptin 901 were only detected in 7 fractions. Pure NOD was lethal to D. pulex and D. magna LC50= 8.4 μg/mL and 5.0 μg/mL, respectively. The newly characterised nodulopeptin 901 was also tested against D. magna (LC50=>100 μg/mL). NOD and nodulopeptin 901 inhibited PP1 with IC50 0.038 μg/mL and 25 μg/mL, respectively. In common with many studies, the maximum amount of NOD was retained within the cells during the seven week growth experiment. In contrast, as much as ~50% of nodulopeptin 901 was detected in the growth media throughout the duration of experiments. To gain further insight on the effects of environmental stress on growth and production of bioactive metabolites in N. spumigena KAC 66, a range of parameters were investigated which included; temperature, salinity, nitrate and phosphorus. In the present study it was investigated that extreme growth conditions have a considerable effect on biomass and toxin levels by N. spumigena KAC 66. The light intensity ranged from 17.35-17.47 μmol/s/m2, 22°C and 11-20 ‰ of salinity were the optimal growth conditions to obtain maximum biomasses, intra and extracellular peptide contents. At 6.5 mg/L nitrate the maximum growth, as indicated by Chl-a and maximum concentrations of intracellular NOD and nodulopeptin 901 were detected found in week 5 and 4, respectively. Temperature had the greatest effect on peptide production. Whilst growth was similar at 22°C, 25°C and 30°C, increase in temperature had a profound effect on NOD production in that an increase from 22°C to 25°C resulted in a 50% decrease in intracellular NOD levels. At 30°C little or no NOD was detected. In contrast, whilst concentrations of nodulopeptin 901 decreased with increasing temperature, they were still detected at consistent levels suggesting they play an important role. The results from phosphate experiment showed Chl-a, cell biomass and peptide production did not show clear dependency on availability of PO-3 4. This is the first study to evaluate the effects of selected environmental parameters on NOD/nodulopeptin 901 production which ultimately may be helpful to explain the distribution, control of natural blooms and toxin levels of N. spumigena in the Baltic Sea and as well as laboratory based experiments. In an attempt further exploit cyanobacterial diversity, 20 strains were isolated from the Dian Lake and 6 from the Dead Sea. The UPLC-PDA-MS analysis of isolates, Microcystis spp. from Dian Lake, China indicated the presence of several peptides namely MC-LR, cyanopeptolin A and aerucyclamides A-D. These new isolates will be examined for biological activity and chemical characterisation in future studies.
20

Historiografía como construcción translatológica y transversal en la novela latinoamericana y española contemporánea

de Toro, Alfonso 27 February 2015 (has links) (PDF)
El tema a tratar, la relación entre el discurso historiográfico y la realidad, por una parte, y la nueva novela histórica y la ficción, por otra, tiene tanto en la literatura como en las ciencias literarias y culturales un carácter tópico. Diversos autores, desde Aristóteles, Cervantes y Diderot hasta Balzac y Flaubert, Borges, Robbe-Grillet y Calvino se han ocupado reiteradamente con el, al parecer, siempre actualísimo fenómeno de la relación entre ficción y realidad.

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