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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.
281

Feasibility of Application of Cathodic Prevention to Cracked Reinforced Concrete in Marine Service

Williams, Kevin 07 July 2014 (has links)
Corrosion can take place as chloride ions accumulate above a critical concentration (CT) at the surface of a reinforcing bar inside concrete in marine service. The initiation of corrosion can be delayed by polarizing the steel cathodically, which is known to increase the value of CT. That effect is the basis of the cathodic prevention (CPrev) method to control corrosion of reinforcing steel in concrete. However, concrete cracks are a common occurrence and at cracks, the buildup of chloride ions is accelerated to the extent that CPrev may be less effective. The findings from an ongoing investigation to determine the effectiveness of cathodic prevention on cracked concrete exposed to a marine environment are presented. Experiments were conducted on reinforced concrete blocks with controlled-width cracks placed along the length of a central reinforcing steel bar. A ponding area on top of each specimen allowed for cyclic exposure to a 5% NaCl solution to imitate a marine environment. Crack widths ranging from 0.01 inch to 0.04 inch and polarization levels ranging from -330 mV to -540 mV were used. The onset of corrosion as a function of time of exposure was determined by measurements of the cathodic current demand needed to reach each target polarization level. The ranking of time to onset of corrosion was used as an indicator to determine how much cathodic prevention is necessary to effectively extend the life of cracked concrete. Results to date suggest that a minimum cathodic polarization level in the range of -540 mV would be needed.
282

Tariff protection and politics: Castlemaine 1870-1901

Hargreaves, Joan Mildred, joan.hargeaves@deakin.edu.au January 1999 (has links)
This study, set within the contextual background of Victorian politics, ‘seeks to identify the economic, political and social implications of tariff protection for the Castlemaine region from 1870-1901. The introduction of the Victorian tariff in 1865 precipitated a reversal of earlier attitudes towards protection by politicians and their constituents. Reasons are sought for changes in the perceptions of the Castlemaine electorate and its political representatives towards the tariff between 1870 and Federation. An examination has been made of the role of the tariff in the creation of employment in the region’s primary and secondary industries together with its influence on politicians, primary and secondary industry leaders and workers. Also explored is the relative impact of the tariff on the economic performance of Castlemaine industries, whether producing for export or domestic markets.
283

Caractérisation du mécanisme de photo-protection impliquant l'orange carotenoid protein (OCP) chez les cyanobactéries

Boulay, C. 30 September 2009 (has links) (PDF)
Pour se protéger des fortes illuminations, les cyanobactéries ont développé un mécanisme de photo-protection nommé qEcya. Sous forte lumière, il diminue la formation d'espèces dérivées de l'oxygène très réactives et dangereuses, en augmentant la dissipation de l'énergie absorbée sous forme de chaleur. L'énergie provenant des phycobilisomes (PBS, les antennes externes des cyanobactéries) atteignant les centres réactionnels est ainsi diminuée. Le mécanisme est induit par l'absorption de la lumière bleue-verte par une protéine photoactive soluble qui attache un caroténoïde : l'Orange Carotenoïd Protein (OCP). Le processus est accompagné d'une diminution de fluorescence réversible. Dans une étude sur les mécanismes de photo-protection sous carence en fer, nous avons montré que le large quenching de fluorescence induit par la lumière bleue-verte est associé à l'OCP et au mécanisme qEcya. Et qu'il n'est pas associé à la protéine IsiA induite sous carence en fer comme cela avait été suggéré dans le passé. Ensuite, j'ai montré que l'OCP et son mécanisme de photo-protection associé sont répandus chez les cyanobactéries à phycobilisomes. Alors que les cyanobactéries contenant l'OCP augmentent leur dissipation d'énergie au niveau des phycobilisomes pour diminuer l'énergie arrivant aux centres réactionnels, il est apparu que les quelques cyanobactéries ne contenant pas l'OCP ont développé une autre stratégie basée sur la dégradation rapide de leurs phycobilisomes en condition de stress. Des résultats préliminaires sur les interactions OCP-PBS sont aussi décrits dans ce travail. Des PBS incubés en présence de l'OCP ont été co-isolés en complexes OCP-PBS dans un gradient de saccharose, même quand seulement des cœurs de PBS ont été mis en présence de l'OCP. Ces résultats suggèrent fortement que l'OCP et les PBS interagissent. Cependant le mécanisme qEcya n'a pas pu être induit in vitro sur ces complexes OCP-PBS purifiés. Le résultat principal de cette thèse est la découverte d'un nouvel acteur essentiel au mécanisme qEcya: une protéine de 13kDa fortement attachée à la membrane. Nous l'avons nommée la Fluorescence Recovery Protein, FRP, car elle est impliquée dans la récupération de l'émission de fluorescence des phycobilisomes dans le mécanisme qEcya après une forte illumination de lumière bleue-verte. La caractérisation de son gène, slr1964, a montré qu'il est conservé en aval du gène de l'OCP chez les cyanobactéries, et qu'il peut être transcrit indépendamment ou co-transcrit avec le gène de l'OCP. De plus, notre étude suggère fortement que l'OCP et la FRP interagissent.
284

LA PROTECTION DU MINEUR DANS LE CYBER ESPACE

Nlend, Cecile 30 November 2007 (has links) (PDF)
Le mineur est un acteur à part entière du cyberespace dont la vulnérabilité intrinsèque pose la question de sa protection au regard la nature d'Internet. Une bonne protection du mineur dans le cyberespace est fonction de son identification en ligne pour l'heure imparfaite. Par ses actes le mineur peut engager sa responsabilité pleine ou limitée pour des actes préjudiciables à autrui et/ou voir engager la responsabilité directe ou indirecte d'autrui pour des délits commis contre lui. La protection du mineur dans le cyberespace est un chantier comportant des avancées réelles néanmoins atténuées par des lacunes persistantes. Les avancées tiennent au fait que, les législations nationales et internationales prennent de plus en plus en compte les spécificités liées à l'activité du mineur dans le cyberespace. Les lacunes tiennent pour l'essentiel à la difficulté de faire coopérer ensemble tous les acteurs et entités du cyberespace à l'échelle internationale.
285

Finns det några skillnader i tillämpning av räddningstjänstlagen och lagen om skydd mot olyckor? / Is there any difference in practising rescuing service law and law of protection against accidents?

Olsson, Martin January 2007 (has links)
<p>Abstract</p><p>Is there any difference in practising rescuing service law and law of protection against accidents?</p><p>C-essay in jurisprudence vt 2007.</p><p>Author: Martin Olsson</p><p>Tutor: Stefan Olsson</p><p>In the last seven years the society has been changing it’s thinking around security. Trough the disasters of the World trade centre in the United States and the natural catastrophe in Thailand. Today it’s very important to have a good reliable security. In Sweden we have made a change in the law regulation around security on field of rescuing. The rescuing service (1986:1102) law do no longer exist and it’s replaced by the law (2003:778) of protection against accident. The question is what this means, has this transformation been a positive change or the other way around. The purpose of this essay is to examine “if it is any difference in practising the rescuing law and law of protection against accident” through a case study. The conclusions is based on material from books, the work around the law and interviews of people working with the law on local, regional, central level. From this facts the essay came too the conclusions that the law of protection against accidents is interpret in an extensive way. The old law was interpreted in a restrictive way. This change has made the interpretation more diffuse than before, especially in the regional and the central level. On the local level it became a problem to work in an effective way. They got a heavier administrative work through the demand of a briefing from the individuals with a business where it’s a risk of a fire too start. These briefings were also very diffused formed for the individuals too understand the meaning of it. One positive effect was the direct aim on some objects with a big lack of standard and making them more effective faster then before. The new law made a different working mode for those who work as a supervisor. In the former law they measured how they organised themselves. Today they measure ability. This is positive way too deal with everything around accidents.</p>
286

Transport of chloride ions during accelerated cathodic protection of reinforced concrete structures

Rehani, Manu 08 June 2000 (has links)
Chloride ion migration was studied under accelerated cathodic protection conditions using 6" x 6" x 6" mortar blocks of varying initial chloride content and water to cement ratios. An iron mesh embedded parallel to one face in the blocks acted as the cathode and zinc was thermally sprayed on the opposite face to form an anode. First, the potential response of two blocks was studied at a current density of 3 mA/ft��. One block was outfitted with a heat sink and moisture barrier while the other block was periodically wetted. Second, eight blocks were polarized at various current densities for a period of one year. In both sets of experiments, the blocks were maintained in controlled humidity and temperature. The potential across the blocks was recorded at periodic intervals and mortar samples were drilled to measure the chloride content as a function of aging. Based on observations of the first study a theoretical model was constructed which indicates that zinc based electrochemical products form at the zinc-concrete interface. The effect of the electrochemical product on raising the resistance across a cathodic protection set-up may be of consequence and should be further studied. Blocks polarized at 6 mA/ft�� exhibited similar behavior as the blocks polarized at 3 mA/ft��, but the response was twice as fast. This result indicates that studying cathodic protection under accelerated conditions is valid. The chloride content of samples obtained from one set of blocks over the course of the experiment was normalized against the initial chloride profile. The normalized profiles were calculated as a function of aging and they supported the hypothesis that chloride ions would move away from the rebar and towards the sprayed zinc anode under cathodic protection. / Graduation date: 2001
287

Protection of pandora moth (Coloradia pandora Blake) eggs from consumption by golden-mantled ground squirrels (Spermophilus lateralis Say)

Gerson, Elizabeth Ann 10 January 1995 (has links)
Endemic populations of pandora moths (Co/oradia pandora Blake), a defoliator of western pine forests, proliferated to epidemic levels in central Oregon in 1986 and increased dramatically through 1 994. Golden-mantled ground squirrels (Spermophilus lateralis Say) consume adult pandora moths, but reject nutritionally valuable eggs from gravid females. Feeding trials with captive S. lateralis were conducted to identify the mode of egg protection. Chemical constituents of fertilized eggs were separated through a polarity gradient of solvent extractions. Consumption of the resulting hexane, dichloromethane, and water egg fractions, and the extracted egg tissue residue, was evaluated by randomized 2-choice feeding tests. Consumption of four physically distinct egg fractions (whole eggs, "whole" egg shells, ground egg shells, and egg contents) also was evaluated. These bioassays indicated that C. pandora eggs are not protected chemically, however, the egg shell does inhibit S. lateralis consumption. Egg protection is one mechanism that enables C. pandora to persist within the forest food web. Spermophilus lateralis, a common and often abundant rodent of central Oregon pine forests, is a natural enemy of C. pandora moths and pupae, but not eggs. / Graduation date: 1995
288

Development of Bifunctional Lysophosphatidic Acid & Lysophosphatidylcholine Activity Probes to Characterize Their Specific Binding Protein Receptors

Nandal, Ritu 01 August 2011 (has links)
Lysophosphatidic acid (LPA) and lysophosphatidylcholine (LPC) activity has been found to be dysregulated in cancer cells and therefore is a crucial target for research. Only a few LPA receptors have been identified to date, namely LPA 1, LPA 2, LPA 3, LPA 4 and peroxisome proliferator-activated receptors (PPAR). In order to identify receptors, we are designing and synthesizing bifunctional LPA and LPC activity probes to characterize their protein targets using activity based protein profiling (ABPP) among other proteomic technologies. By synthesizing bifunctional signaling probes that can mimic the naturally occurring LPA and LPC molecules and selectively capture receptors by virtue of their binding properties, we can identify and study the different proteins that are aberrantly expressed in various pathophysiological states such as cancer.
289

Tau nucléaire : un acteur clé dans le stress neuronal

Sultan, Audrey 17 December 2010 (has links) (PDF)
Les protéines Tau sont impliquées dans plusieurs maladies neurodégénératives dénommées tauopathies, dont la plus fréquente est la maladie d'Alzheimer. Ces maladies se caractérisent par une accumulation intracellulaire de protéines Tau hyper- et anormalement phosphorylées sous forme de filaments. Ces lésions, dont l'origine et le rôle exact restent mal connus, sont au cœur d'un processus dégénératif conduisant à de nombreux troubles cognitifs et/ou moteurs et aboutissant le plus souvent à un syndrome de démence. Les protéines Tau appartiennent à la famille des protéines associées aux microtubules. Elles sont principalement neuronales et majoritairement localisées dans les axones où elles modulent l'assemblage et la stabilisation des microtubules. La mise en évidence d'autres localisations au sein des neurones, notamment dans le noyau, suggère néanmoins que Tau pourrait être une protéine multifonctionnelle. Cependant, bien que Tau soit observée dans le noyau des neurones, sa fonction n'a jamais été étudiée. Des études in vitro ont montré que la protéine Tau purifiée est capable de se lier et de stabiliser l'ADN en le protégeant de la dégradation par les DNAses ainsi que des altérations provoquées par les radicaux libres. Les travaux présentés dans cette thèse ont eu pour objectif d'étudier in situ, la fonction de Tau nucléaire sur l'intégrité de l'ADN en condition de stress. Dans ce but, nous avons développé et caractérisé des modèles dans lesquels un stress thermique ou un stress oxydant, un mécanisme précocement impliqué dans la maladie d'Alzheimer, modulent la quantité de Tau dans le noyau de neurones. Nos résultats indiquent qu'en réponse à une hyperthermie, stress non toxique pour les cellules, Tau est déphosphorylée et s'accumule dans le noyau des neurones où elle se lie à l'ADN. Afin d'étudier le rôle de Tau nucléaire, nous avons analysé par Comet assay l'effet de l'hyperthermie sur l'intégrité de l'ADN dans des neurones sauvages ou déficients en Tau. Les résultats ont montré que ce type de stress entraîne des dommages à l'ADN spécifiquement dans les neurones déficients en Tau. Dans ces neurones, l'expression à l'aide de vecteurs adénoviraux de la Tau humaine possédant ou non une séquence de localisation nucléaire pour cibler Tau dans le compartiment nucléaire, prévient les dommages induits par le stress. Inversement, une hypothermie induit une hyperphosphorylation de Tau et prévient son accumulation dans le noyau. Dans ce contexte, nous avons observé la présence de dommages à l'ADN dans les neurones sauvages. L'ensemble de ces résultats suggèrent que l'accumulation de Tau dans les noyaux protège l'ADN neuronal des dommages induits par un stress. En conclusion, ce travail montre, pour la première fois, un nouveau rôle de Tau en tant qu'acteur essentiel de la réponse précoce à un stress dans le neurone où la protéine Tau protège l'intégrité de l'ADN. Dans les tauopathies, l'altération pathologique de Tau pourrait avoir un impact délétère sur sa fonction neuroprotectrice de l'ADN et contribuer ainsi à la physiopathologie de ces maladies.
290

Finns det några skillnader i tillämpning av räddningstjänstlagen och lagen om skydd mot olyckor? / Is there any difference in practising rescuing service law and law of protection against accidents?

Olsson, Martin January 2007 (has links)
Abstract Is there any difference in practising rescuing service law and law of protection against accidents? C-essay in jurisprudence vt 2007. Author: Martin Olsson Tutor: Stefan Olsson In the last seven years the society has been changing it’s thinking around security. Trough the disasters of the World trade centre in the United States and the natural catastrophe in Thailand. Today it’s very important to have a good reliable security. In Sweden we have made a change in the law regulation around security on field of rescuing. The rescuing service (1986:1102) law do no longer exist and it’s replaced by the law (2003:778) of protection against accident. The question is what this means, has this transformation been a positive change or the other way around. The purpose of this essay is to examine “if it is any difference in practising the rescuing law and law of protection against accident” through a case study. The conclusions is based on material from books, the work around the law and interviews of people working with the law on local, regional, central level. From this facts the essay came too the conclusions that the law of protection against accidents is interpret in an extensive way. The old law was interpreted in a restrictive way. This change has made the interpretation more diffuse than before, especially in the regional and the central level. On the local level it became a problem to work in an effective way. They got a heavier administrative work through the demand of a briefing from the individuals with a business where it’s a risk of a fire too start. These briefings were also very diffused formed for the individuals too understand the meaning of it. One positive effect was the direct aim on some objects with a big lack of standard and making them more effective faster then before. The new law made a different working mode for those who work as a supervisor. In the former law they measured how they organised themselves. Today they measure ability. This is positive way too deal with everything around accidents.

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