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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

The Neurophysiological Correlates of Children's and Adults' Judgments of Moral and Social Conventional Violations

Lahat, Ayelet 31 August 2011 (has links)
Adults and young children have been found to distinguish between moral and social conventional acts, which are considered to entail distinct domains of reasoning (e.g., Turiel 1983). Recently, research has begun to examine the neural basis of moral judgments (e.g., Greene et al., 2001), but these studies did not examine the development of neurocognitive processing of judgments in these two domains. The present study focused on detection of cognitive conflict as a neurocognitive process that distinguished judgments of moral and conventional violations. The N2 component of the ERP was examined in order to determine whether the two types of violation are associated with different neurophysiological correlates and whether they change with development. In a series of five experiments, reaction times and ERPs were recorded from 12- to 14-year-old children and undergraduates who read scenarios that had one of three possible endings: (1) moral violations, (2) conventional violations, (3) no violation (neutral acts). Participants judged whether the act was acceptable or unacceptable when a rule was assumed or removed. Results indicate that reaction times were faster for moral than conventional violations when a rule was assumed for both undergraduates and children, as well as when a rule was removed for children but not for undergraduates. ERP data indicated that adults’, but not children’s, N2 amplitudes were larger (i.e., more negative) for conventional than iii moral violations when a rule was assumed. Furthermore, source analysis indicated generators for the N2 in dorsomedial and ventromedial prefrontal cortices. The results suggest that judgments of conventional violations involve increased conflict detection as compared to moral violations, and these two domains are processed differently across development. The findings were explained by the idea that judgments of conventional violations are more explicitly dependant on rules, whereas judgments of moral violations are based more directly on the intrinsic negative consequences of the act.
12

Electrophysiological Correlates of Multisensory Integration in Peripersonal Space: an Exploration of the Auditory Attention System

Surdhar, Ian S Unknown Date
No description available.
13

The literary-theoretical influences on the thought of Hans Frei and Paul Ricoeur, with reference to narrative identity

Nanno, Edward January 1997 (has links)
This thesis analyses those differences In interpretation which occur when separate literary-theoretical approaches are applied to biblical texts. Hans Frei suggests that the biblical texts describe the world in a way which he calls "realistic narrative". Paul Ricoeur's hermeneutic recognises the disclosive power of the text and translates the subject matter of the text into a "way-of- being-in-the-world". Thus, the primary identity disclosed by the biblical narratives differs. For Frei, it is the identity of Jesus which is disclosed; for Ricoeur, it is "our common human Christian identity". These two thinkers have usually been compared theologically. However, I contend that the theological investigations of both Frei and Ricoeur have been influenced by the literary approaches which guide their theological work. I give an exposition of this relationship in chapter one. In chapter two, I sketch out the implications of this relationship, focusing on the issue of narrative identity. In the final chapter, critiques of both systems are investigated as I attempt to deal with the force of these objections. This dissertation investigates Frei's and Ricoeur's construals of narrative identity (as constructed through the reading of Biblical texts). My working hypothesis is that the construals of identity formulated by Frei and Ricoeur rely upon formalist, narrative "interpretations". My thesis contends that in their respective approaches to the notion of narrative identity, neither thinker has completely abandoned his early literary-theoretical roots in his theological proposals.
14

High-Pressure Vibrational Spectroscopic and Crystallographic Investigations of the N2-Ar and N2-Kr Binary Systems

Miles, Shawna January 2016 (has links)
In this work, the phase behavior of binary systems comprising nitrogen and a noble element (nitrogen + argon and nitrogen + krypton) was studied at high density in the condensed state. Following the work of Lotz et al.[2001], the main goal of this work was to further investigate the pressure-concentration phase diagram as well as to look for the possible formation of van der Waals compounds at elevated pressures and room temperature and study their physical properties, using both vibrational spectroscopy and X-ray diffraction. The observed phases, formed by single atoms and/or simple molecules in the binary systems were solved and modeled for their corresponding crystalline structures. From experimental results, lattice parameters for all crystalline structures and phase transitions, if detected, have been observed to shift with respect to that of the pure substances. The analyses and characterization of these binary systems are discussed in detail.
15

Porous Organic Polymers for CO2 Capture

Teng, Baiyang 05 1900 (has links)
Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.
16

QTL analysis of ray pattern in Caenorhabditis elegans recombinant inbred lines

Guess, Adam Joseph 28 March 2008 (has links)
No description available.
17

Simulating Nitric Oxide in the lower thermosphere using a 3D model

Venkataramani, Karthik 10 January 2012 (has links)
Nitric oxide (NO), despite being a minor species, influences the chemistry, composition and energy balance of the earth's atmosphere above 90 kilometers. Variations in its density have been shown to strongly correlate with solar x-ray irradiance at lower latitudes and precipitating energetic particles at higher latitudes. Though the broad variations in NO densities with altitude and latitude are well known, there are still uncertainties associated with its chemistry. It is important to accurately model NO and its associated chemistry in an atmospheric model in order to obtain an accurate representation of the thermosphere. The NCAR Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) is a three dimensional first principles based model which includes a self consistent aeronomic scheme that solves for winds, temperatures and densities of various neutral and charged species in the earth's upper atmosphere. Using a combination of the solar irradiance spectrum and solar indices as inputs, the model computes these outputs at every time step. The ability of the TIEGCM to predict NO densities in the thermosphere is examined by comparing results from the model with data obtained from the Student Nitric Oxide Explorer (SNOE). The comparisons are made for the year 1999 at 110 km and 150 km at the equator. Changes are made to the NO chemistry present in the model to reflect recent results obtained from laboratory data. Paricularly, the reaction of atomic oxygen with the first excited electronic state of nitrogen, N <sub>2 </sub>(A) has been shown to play an important role in the production of NO. These changes are introduced to the model and their effect on NO densities is studied. Overall, it is seen that the updated chemistry scheme reduces the model agreement with the SNOE data at 110 km while slightly improving the agreement at a 150 km. The loss of agreement at 110 km is attributed to the fact that the neutral temperatures and atomic oxygen densities calculated by the TIEGCM are in sharp disagreement to the temperatures predicted by the NRL-MSIS at a 110 km, on which the new chemistry scheme is based. While the chemistry scheme used in this thesis is a step in the right direction for modelling NO using the TIEGCM, the parameters used were determined from the best fit obtained from the 1-D NO model. In the light of the differences between the NRL-MSIS and TIEGCM, it is necessary to return to the laboratory data and modify the parameters used here to achieve a better agreement with the data. / Master of Science
18

Etude et optimisation de poly(butylène succinate) biosourcés pour l’injection moussage à l’azote par voie physique / Study and optimization of biobased poly(butylene succinate) for microcellular injection molding using nitrogen

Ykhlef, Nazim 06 December 2018 (has links)
Ce travail concerne le développement de polymères alvéolaires biosourcés adaptés à l’injection microcellulaire physique (Mucell®) ainsi que l’identification des leviers (procédé et/ou matériau) permettant de contrôler la structure cellulaire.Les paramètres directeurs du procédé ont été optimisés à l’aide d’un plan d’expérience de type Taguchi permettant d’atteindre un allégement de 15% tout en conservant un niveau de performance mécanique acceptable. Par ailleurs, des modifications structurales du PBS ont été menées dans le but de contrôler le processus de formation de la structure cellulaire (dissolution du gaz, nucléation, croissance cellulaire et stabilisation de la structure). La morphologie cellulaire a été améliorée en modifiant la conformation moléculaire des chaînes, en favorisant la nucléation hétérogène ou en modifiant les propriétés élongationnelles et la tension de surface du matériau. La formulation résultante a permis une diminution de plus de 80% de la taille des cellules et une densité cellulaire multipliée par 450.Enfin, une technique de mesure du comportement rhéologique du système monophasé polymère/gaz a été développée à l’aide d’une buse instrumentée en ligne permettant d’évaluer l’effet de la dissolution du gaz sur la viscosité du matériau en fonction des conditions expérimentales de l’étude. / This work focused on the development of biobased polymer foams adapted to the microcellular injection molding (Mucell®) and the identification of the key parameters (process and/or material) controlling the cell structure.The process parameters were optimized using a Taguchi design of experiment which achieves 15% lightweighting while maintaining acceptable mechanical performances. In addition, structural modifications of PBS were carried out in order to control the foaming mechanism (gas dissolution, cell nucleation, cell growth and cell stabilization). Cell morphology has been improved by modifying the molecular conformation, promoting heterogeneous nucleation, or by adjusting the extensional viscosity and surface tension of the material. The resulting formulation exhibit a decrease of more than 80% in cell size and a cell density multiplied by 450.Finally, a measurement technique for the rheological behavior of the single phase polymer/gas mixture was developed using an instrumented on-line nozzle to evaluate the effect of gas dissolution on the viscosity under experimental conditions.
19

Síntese de membranas zeolíticas (ZSM-5/y-ALUMINA e ZSM-5/a-ALUMINA) por Pore-Plugging para permeação de gás N2. / Synthesis of zeolite membranes (ZSM-5 / y-ALUMINA and ZSM-5 / a-ALUMINA) by Pore-Plugging for N2 gas permeation

SCHEIBLER, Janaina Rafaella. 23 March 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-23T18:44:54Z No. of bitstreams: 1 JANAINA RAFAELLA SCHEIBLER - DISSERTAÇÃO PPGEQ 2015..pdf: 2465420 bytes, checksum: cbecc726b67d3d76a334570b655735eb (MD5) / Made available in DSpace on 2018-03-23T18:44:54Z (GMT). No. of bitstreams: 1 JANAINA RAFAELLA SCHEIBLER - DISSERTAÇÃO PPGEQ 2015..pdf: 2465420 bytes, checksum: cbecc726b67d3d76a334570b655735eb (MD5) Previous issue date: 2015 / Entre as membranas inorgânicas microporosas, as membranas zeolíticas constituem uma tecnologia promissora, devido às suas potenciais aplicações normalmente na desidratação do álcool, separação de moléculas de gás, separação de isômeros ou em processos químicos, incluindo reações de esterificação. Sob este aspecto, torna-se imprescindível o estudo das rotas de preparação desses materiais, visando desenvolver produtos com qualidade e a baixo custo. Portanto, a inovação deste estudo se dá na síntese de membranas zeolíticas via método de síntese poreplugging visando a utilização das membranas inorgânicas para permeação gasosa de N2. Neste trabalho foram desenvolvidos os seguintes materiais: zeólita ZSM-5, membranas cerâmicas (γ-alumina e α-alumina) e as membranas zeolíticas (ZSM5/γ-alumina e ZSM-5/α-alumina). A zeólita ZSM-5 foi sintetizada por meio do método hidrotérmico. As membranas cerâmicas (γ-alumina e α-alumina) foram preparadas a partir da técnica de conformação de pós cerâmicos e posteriormente submetidas à sinterização a uma temperatura de 1000 ºC/1h e 1200 ºC/1h respectivamente. A preparação das membranas zeolíticas (ZSM-5/γ-alumina e ZSM-5/α-alumina) foi realizada com base no método pore in plugging. As amostras foram caracterizadas a partir das técnicas de difração de raios X e Microscopia Eletrônica de Varredura. Os resultados experimentais permitem diversas conclusões acerca do desenvolvimento dos materiais: zeólita ZSM-5, membranas cerâmicas (γ-alumina e α-alumina) e membranas zeolíticas (ZSM-5/γ-alumina e ZSM-5/α-alumina). A partir da difração de raios X, foi possível verificar que o método de síntese empregado, foi efetivo na obtenção da zeólita ZSM-5. O difratograma apresentou picos característicos de uma zeólita ZSM-5 quando comparada ao padrão. Os resultados obtidos por DRX para as membranas cerâmicas (γ-alumina e α-alumina) demonstraram a formação de picos característicos do óxido de alumínio, os materiais são cristalinos e puros. Para o método pore-plugging pode se dizer que é um método promissor, pois mostrou uma formação satisfatória da camada zeolítica no resultado do DRX de ambas as membranas zeolíticas (ZSM-5/γ-alumina e ZSM-5/α-alumina). / Among the microporous inorganic membranes, zeolite membranes are a promising technology due to their potential applications normally in alcohol dehydration, separation of gas molecules, separation of isomers or chemical processes, including esterification reactions. In this regard, it is essential to study the preparation of these materials routes in order to develop products with quality and low cost. Therefore, innovation of this study gives the synthesis of zeolite membranes via pore-plugging synthesis method aimed at the use of inorganic membranes for gas permeation N2. In this work the following materials were developed: ZSM-5 zeolite, ceramic membranes (γ-alumina and α-alumina) and zeolitic membranes (ZSM-5/γ-alumina and ZSM-5/α-alumina). Zeolite ZSM-5 was synthesized by the hydrothermal method. Ceramic membranes (γ-alumina and α-alumina) were prepared from the ceramic powder forming technique, and subsequently subjected to a sintering temperature of 1000 °C/1h and 1200 °C/1h respectively. The preparation of zeolite membranes (ZSM-5/γ-alumina and ZSM-5/α-alumina) was carried out based on the method in pore plugging. The samples were characterized from the techniques of X diffraction and scanning electron microscopy rays. The experimental results allow several conclusions about the development of materials: zeolite ZSM-5, ceramic membranes (γ-alumina and α-alumina) and zeolite membranes (ZSM-5/γ-alumina and ZSM-5/αalumina). From the X-ray diffraction, it found that the method of synthesis used was effective in obtaining the zeolite ZSM-5. The XRD pattern showed peaks characteristic of ZSM-5 compared to the standard. The results obtained by XRD ceramic membranes (γ-alumina and α-alumina) showed the formation of peaks characteristic of aluminum oxide, the materials are crystalline and pure. For the poreplugging method can be said to be a promising method because it showed a satisfactory formation of the zeolite layer on the result of XRD both zeolite membranes (ZSM-5/γ-alumina and ZSM-5/α-alumina).
20

Influence de la biodisponibilité des nutriments sur la fixation de N2 et réponse de Crocosphaera watsonii face à la limitation en fer / Impact of nutrients bioavailability on N2 fixation and response of Crocosphaera watsonii to iron limitation

Jacq, Violaine 30 June 2014 (has links)
La fixation de N2, ou diazotrophie, est un processus biogéochimique majeur en raison de son apport en azote nouveau dans la couche de surface de l’océan. Cependant ses facteurs de contrôle restent mal connus. Le fer, dont les concentrations de surface sont faibles, est un élément potentiellement limitant de la fixation de N2 du fait du contenu en fer important de la nitrogénase. En raison de leur découverte récente, peu d’études ont été menées sur les cyanobactéries diazotrophes unicellulaires (UCYN) pouvant être responsables de ~50% de la fixation de N2 à l’échelle globale. Des expériences en culture ont permis de caractériser et quantifier pour la première fois la réponse d’une UCYN, Crocosphaera watsonii, face à la limitation en fer. En condition de limitation en fer, il a été observé une réduction de la croissance et des taux de fixation de N2 ainsi qu’une stratégie d’adaptation des cellules avec une diminution de leur volume. La stimulation de la croissance et de l’activité de C. watsonii cultivées en condition de limitation en fer suite à l’ajout d’une pluie saharienne artificielle a permis de mettre en évidence qu’une partie au moins du fer issu de poussières désertiques est biodisponible. En Atlantique subtropical Nord, où nous avons déterminé une forte contribution de la fixation de N2 à la production nouvelle, nous avons observé une limitation de la fixation de N2 et de la production primaire principalement par les phosphates et mis en évidence le rôle des métaux traces dans le contrôle de la fixation de N2. Un ajout de pluie saharienne a permis de stimuler systématiquement la fixation de N2 et la production primaire. / Despite the biogeochemical importance of N2 fixation, which represents the largest source of newly-Fixed nitrogen to the open ocean, some uncertainties remain about its controlling factors. Iron (Fe) is widely suspected as a key controlling factor due to the high Fe content of the nitrogenase complex and to its low concentration in oceanic surface seawaters. N2 fixation rates associated with unicellular N2 fixing cyanobacteria (UCYN) were estimated to be ~50% of the total N2 fixation at global scale, but as they have been recently discovered few studies have been conducted on these organisms. We performed culture experiments in order to quantify for the first time the response of an UCYN, Crocosphaera watsonii, to Fe limitation. Reduction of ambient Fe concentration led to significant decreases in growth rate and N2 fixation rates per cell and we observed an adaptive strategy to Fe limitation with a cell volume reduction. Then, the enhancement of growth and activity of C. watsonii under Fe limitation condition after artificial Saharan rain addition highlighted that at least a part of the Fe released by the dust is bioavailable. In subtropical North Atlantic, an important contribution of N2 fixation to new production was observed and we showed that primary production and N2 fixation were globally P-Limited. We revealed that trace metals play a key role in controlling N2 fixation in this area. Saharan rain addition stimulated N2 fixation, presumably by supplying these nutrients. All these results contribute to our knowledge of the control of oceanic N2 fixation and provide new insight about interactions between Fe, nitrogen and carbon biogeochemical cycles.

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