2017
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Effect of shot peening on the residual stress and mechanical behaviour of low-temperature and high-temperature annealed martensitic gear steel 18CrNiMo7-6

År: 2017

A martensitic gear steel (18CrNiMo7-6) was annealed at 180 degrees C for 2h and at similar to 750 degrees C for 1h to design two different starting microstructures for shot peening. One maintains the original as-transformed martensite while the other contains irregular-shaped sorbite together with ferrite. These two materials were shot peened using two different peening conditions. The softer sorbite + ferrite microstructure was shot peened using 0.6 mm conditioned cut steel shots at an average speed of 25 m/s in a conventional shot peening machine, while the harder tempered martensite steel was shot peened using 1.5 mm steel shots at a speed of 50 m/s in an in-house developed shot peening machine. The shot speeds in the conventional shot peening machine were measured using an in-house lidar set-up. The microstructure of each sample was characterized by optical and scanning electron microscopy, and the mechanical properties examined by microhardness and tensile testing. The residual stresses were measured using an Xstress 3000 G2R diffractometer equipped with a Cr K alpha x-ray source. The correspondence between the residual stress profile and the gradient structure produced by shot peening, and the relationship between the microstructure and strength, are analyzed and discussed.
Original languageEnglish
JournalI O P Conference Series: Materials Science and Engineering
Volume219
Number of pages7
ISSN1757-8981
DOIs
StatePublished - 2017

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Evidence of local and regional freshening of Northeast Greenland coastal waters

År: 2017

Evidence of local and regional freshening of Northeast Greenland coastal waters

Sejr, M. K., Stedmon, C. A., Bendtsen, J., Abermann, J., Juul-Pedersen, T., Mortensen, J. & Rysgaard, S. 2017 In : Scientific Reports. 7, 1, 13183

Publication: Research - peer-reviewJournal article – Annual report year: 2017

The supply of freshwater to fjord systems in Greenland is increasing as a result of climate change-induced acceleration in ice sheet melt. However, insight into the marine implications of the melt water is impaired by lack of observations demonstrating the fate of freshwater along the Greenland coast and providing evaluation basis for ocean models. Here we present 13 years of summer measurements along a 120 km transect in Young Sound, Northeast Greenland and show that sub-surface coastal waters are decreasing in salinity with an average rate of 0.12 ± 0.05 per year. This is the first observational evidence of a significant freshening on decadal scale of the waters surrounding the ice sheet and comes from a region where ice sheet melt has been less significant. It implies that ice sheet dynamics in Northeast Greenland could be of key importance as freshwater is retained in southward flowing coastal currents thus reducing density of water masses influencing major deep water formation areas in the Subarctic Atlantic Ocean. Ultimately, the observed freshening could have implications for the Atlantic meridional overturning circulation.
Original languageEnglish
Article number13183
JournalScientific Reports
Volume7
Issue number1
ISSN2045-2322
DOIs
StatePublished - 2017

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FLEXSELECT: counter-herding device to reduce bycatch in crustacean trawl fisheries

År: 2017

FLEXSELECT is a simple counter-herding device which aims at reducing the bycatch of fish by scaring them away from the trawl path without affecting the catches of the target species. FLEXSELECT was tested in the Norway lobster (Nephrops norvegicus) directed trawl fishery, as this includes bycatch of both roundfish and flatfish. Length-based data were collected for Nephrops, four roundfish species (cod, haddock, whiting and hake) and two flatfish species (plaice and lemon sole) and length-based catch comparisons performed. No significant effect on the target species, Nephrops, was detected, whereas a reduction of 39% (CI: 29-46 %) was obtained for the overall number of fish. Catches of all the six fish species examined were significantly reduced by FLEXSELECT, with the efficiency varying considerably among species and over length classes. No significant diel differences were found for either roundfish or flatfish species. FLEXSELECT prevents bycatch species from interacting with the trawl, thus most likely enhancing their survival and fitness. Moreover, its fast attachment system makes FLEXSELECT a flexible tool, adaptable to different fisheries and catch goals.
Original languageEnglish
JournalCanadian Journal of Fisheries and Aquatic Sciences
ISSN0706-652X
DOIs
StatePublished - 2017

 

The development of tools for tracing and evaluating the genetic impact of fish from aquaculture

År: 2017

The development of tools for tracing and evaluating the genetic impact of fish from aquaculture

Bargelloni, L. & Nielsen, E. E. 2017 In : Aquaculture. 472, p. 87

Publication: Research - peer-reviewConference abstract in journal – Annual report year: 2017

Original languageEnglish
JournalAquaculture
Volume472
Pages (from-to)87
ISSN0044-8486
StatePublished - 2017
Event12th International Symposium on Genetics in Aquaculture - Santiago de Compostella, Spain

Conference

Conference12th International Symposium on Genetics in Aquaculture
CountrySpain
CitySantiago de Compostella
Period21/06/201527/06/2015

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Neuroendocrine and immune responses undertake different fates following tryptophan or methionine dietary treatment: Tales from a teleost model

År: 2017

Neuroendocrine and immune responses undertake different fates following tryptophan or methionine dietary treatment: Tales from a teleost model

Azeredo, R., Machado, M., Afonso, A., Fierro-Castro, C., Reyes-López, F. E., Tort, L., Gesto, M., Conde-Sieira, M., Míguez, J. M., Soengas, J. L., Kreuz, E., Wuertz, S., Peres, H., Oliva-Teles, A. & Costas, B. 2017 In : Frontiers in Immunology. 8, 14 p., 1226

Publication: Research - peer-reviewJournal article – Annual report year: 2017

Methionine and tryptophan appear to be fundamental in specific cellular pathways involved in the immune response mechanisms, including stimulation of T-regulatory cells by tryptophan metabolites or pro-inflammatory effects upon methionine supplementation. Thus, the aim of this study was to evaluate the immunomodulatory effect of these amino acids on the inflammatory and neuroendocrine responses in juveniles of European seabass, Dicentrarchus labrax. To achieve this, goal fish were fed for 14 days methionine and tryptophan-supplemented diets (MET and TRP, respectively, 2× dietary requirement level) or a control diet meeting the amino acids requirement levels (CTRL). Fish were sampled for immune status assessment and the remaining fish were challenged with intraperitoneally injected inactivated Photobacterium damselae subsp. piscicida and sampled either 4 or 24 h post-injection. Respiratory burst activity, brain monoamines, plasma cortisol, and immune-related gene expression showed distinct and sometimes opposite patterns regarding the effects of dietary amino acids. While neuroendocrine intermediates were not affected by any dietary treatment at the end of the feeding trial, both supplemented diets led to increased levels of plasma cortisol after the inflammatory insult, while brain monoamine content was higher in TRP-fed fish. Peripheral blood respiratory burst was higher in TRP-fed fish injected with the bacteria inoculum but only compared to those fed MET. However, no changes were detected in total antioxidant capacity. Complement factor 3 was upregulated in MET-fed fish but methionine seemed to poorly affect other genes expression patterns. In contrast, fish fed MET showed increased immune cells numbers both before and after immune challenge, suggesting a strong enhancing effect of methionine on immune cells proliferation. Differently, tryptophan effects on inflammatory transcripts suggested an inhibitory mode of action. This, together with a high production of brain monoamine and cortisol levels, suggests that tryptophan might mediate regulatory mechanisms of neuroendocrine and immune systems cooperation. Overall, more studies are needed to ascertain the role of methionine and tryptophan in modulating (stimulate or regulate) fish immune and neuroendocrine responses.
Original languageEnglish
Article number1226
JournalFrontiers in Immunology
Volume8
Number of pages14
ISSN1664-3224
DOIs
StatePublished - 2017


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20 OKTOBER 2017