Search results for "TLE"
showing 10 items of 2417 documents
Localized hydrogen cracking in the austenitic phase of a duplex stainless steel
1996
The aim of this study is to investigate the role of hydrogen on the mechanical behavior of an austenitic phase, in the particular situation of duplex stainless steels. In these duplex alloys, in presence of hydrogen, the ferritic phase is embrittled by hydrogen and the resistance to cracking is mainly related to the behavior of the austenitic phase. Thus, a discussion of the role of hydrogen at the crack tip of a duplex alloy (as function of the microstructure) has been proposed by T. Perng and C.J. Altester after experiments conducted in gaseous environment. A similar experimental approach has been followed in this study; slow strain rate tests (SSRT) have been performed on duplex stainles…
Kinetics of Sigma Phase Precipitation in Niobium-Stabilized Austenitic Stainless Steel and Effect on the Mechanical Properties
2014
Stabilized austenitic stainless steels are widely used in nuclear and oil industries. The 316 Nb steel grade presented in this study holds a small amount of delta ferrite in the austenitic matrix which tends to transform into sigma phase during prolonged exposures in the temperature range of 600-1000°C. Sigma phase is promoted by ferritic elements such as chromium, molybdenum, niobium and silicon. Time-Temperature-Transformation (TTT) diagram of the δ-ferrite evolution is established thanks to DSC experiments and quantitative metallographic analysis. It is observed that the highest sigma phase formation rate occurs between 800 and 900°C, and that the transformation of ferrite begins after a…
A Mechano-Chemical Coupling for Hydrogen Diffusion in Metals Based on a Thermodynamic Approach
2014
Hydrogen diffusion in metals is still an ongoing topic of research due to its technical relevance (hydrogen embrittlement, hydrogen storage...). In the last decades, significant progress in understanding the time evolution of the hydrogen concentration in solids was completed. This paper presents a modeling of hydrogen diffusion with a general and thermodynamically based diffusion concept coupled with mechanical and chemical aspects. This model was previously used to simulate the oxidation of a metal [1][2]. This concept has been upgraded to offer a thoroughly macroscopic behavior law used to simulate hydrogen diffusion in metal parts under mechanical loadings. The thermodynamic approach of…
Redescription of the forgotten New Caledonian weevil genus
2018
Abstract Callistomorphus is one of the “forgotten” genera of the tribe Eugnomini inhabiting rain forest in New Caledonia. In this paper, the genus Callistomorphus and the type species C.farinosus are redescribed. Eight new species, Callistomorphusfundatussp. n., C.gibbussp. n., C.malleussp. n., C.minimussp. n., C.rutaisp. n., C.szoltysisp. n., C.torosussp. n. and C.turbidussp. n., are described, originating from the main island of New Caledonia. Illustrations and SEM photographs of the external morphology and the male and female terminalia are provided, as well as dorsal habitus colour photographs of the adults, a key to the species, a distribution map, and a discussion of the systematic po…
A cost of maternal care in the dung beetle Onthophagus taurus?
2002
Parental care theory assumes that investment in current offspring will trade against future investment. A number of field studies on birds have used clutch size manipulations to demonstrate a survival cost to chick rearing. However, such studies do not account for costs accrued during earlier stages of reproduction because not all aspects of reproductive effort are manipulated by varying the number of nestlings. In this study, we investigate the effect of reproductive effort on female survival in the dung beetle, Onthophagus taurus. By experimentally manipulating mating status and dung availability, we demonstrate that virgin females survive longer than mated females and that the survival o…
Generic Method for Modular Surface Modification of Cellulosic Materials in Aqueous Medium by Sequential Click-Reaction and Adsorption
2012
A generic approach for heterogeneous surface modification of cellulosic materials in aqueous medium, applicable for a wide range of functionalizations, is presented. In the first step, carboxymethyl cellulose (CMC) modified with azide or alkyne functionality, was adsorbed on a cellulosic substrate, thus, providing reactive sites for azide–alkyne cycloaddition click reactions. In the second step, functional units with complementary click units were reacted on the cellulose surface, coated by the click-modified CMC. Selected model functionalizations on diverse cellulosic substrates are shown to demonstrate the generality of the approach. The concept by sequentially combining the robust physic…
Trasparenza, whistleblowing e pubblica amministrazione. Elementi per una riflessione
2018
This chapter focuses on recent legislation that has concerned certain levels of the Public Administration, with particular reference to those interventions that are based on a constant process of empowering people within the usual place of work. In this sense, the focus is particularly on the tool called whistleblowing. Specifically, it is a practice aimed at indicating the presence of the violation of one or more rules within the usual place of work. In the chapter I dwell on some problematic aspects related to the relevant legislation also through some comparisons with the US legislation.
Endring av organisasjonsstruktur : konsekvenser for bygg- og anleggsprosjekter
2015
Masteroppgave økonomi og administrasjon- Universitetet i Agder, 2015 Denne masteroppgaven er en kvalitativ studie som tar for seg forskningsspørsmålet "Hvordan blir prosjekter i en bygg- og anleggsorganisasjon påvirket av å gå fra matriseorganisasjonsstruktur til linjeorganisasjonsstruktur?". Jernbaneverket har vært benyttet som caseorganisasjon ettersom de i 2014 endret sin organisasjonsstruktur på dette viset. Målet for oppgaven har vært å forstå hvilken betydning organisasjonsstruktur har på gjennomføring av prosjekt, og hvilke konsekvenser en endring har. Dette da organisasjoner i dag har begynt å vende tilbake til den tradisjonelle linjeorganisasjonen. Problemstillingen er særlig gjeld…
Development of fluorogenic probe-based PCR assays for the detection and quantification of bovine piroplasmids.
2009
This paper reports two new quantitative PCR (qPCR) assays, developed in an attempt to improve the detection of bovine piroplasmids. The first of these techniques is a duplex TaqMan assay for the simultaneous diagnosis of Babesia bovis and B. bigemina. This technique is ideal for use in South America where bovids harbour no theilerids. The second technique, which is suitable for the diagnosis of both babesiosis and theileriosis worldwide, involves fluorescence resonance energy transfer (FRET) probes. In FRET assays, Babesia bovis, B. divergens, Babesia sp. (B. major or B. bigemina), Theileria annae and Theileria sp. were all identifiable based on the melting temperatures of their amplified f…
Small GTP-binding proteins of the Rho- and Ras-subfamilies are not involved in the actin rearrangements induced by attaching and effacingEscherichia …
1998
Attaching and effacing Escherichia coli (AEEC) are extracellular pathogens that induce the formation of actin-rich structures at their sites of attachment to eukaryotic host cells. We analysed whether small GTP-binding proteins of the Rho- and Ras-subfamilies, which control the cellular actin system, are essential for these bacterial-induced microfilament reorganizations. For this purpose we specifically inactivated them using the Clostridium difficile toxins TcdB-10463 and TcdB-1470. Such treatment led to a dramatic breakdown of the normal actin cytoskeleton, but did not abrogate the bacterial-induced actin rearrangements. Our data therefore indicate that the microfilament reorganizations …