| 1. |
- Obst, Matthias, 1974, et al.
(författare)
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A Marine Biodiversity Observation Network for Genetic Monitoring of Hard-Bottom Communities (ARMS-MBON)
- 2020
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Marine hard-bottom communities are undergoing severe change under the influence of multiple drivers, notably climate change, extraction of natural resources, pollution and eutrophication, habitat degradation, and invasive species. Monitoring marine biodiversity in such habitats is, however, challenging as it typically involves expensive, non-standardized, and often destructive sampling methods that limit its scalability. Differences in monitoring approaches furthermore hinders inter-comparison among monitoring programs. Here, we announce a Marine Biodiversity Observation Network (MBON) consisting of Autonomous Reef Monitoring Structures (ARMS) with the aim to assess the status and changes in benthic fauna with genomic-based methods, notably DNA metabarcoding, in combination with image-based identifications. This article presents the results of a 30-month pilot phase in which we established an operational and geographically expansive ARMS-MBON. The network currently consists of 20 observatories distributed across European coastal waters and the polar regions, in which 134 ARMS have been deployed to date. Sampling takes place annually, either as short-term deployments during the summer or as long-term deployments starting in spring. The pilot phase was used to establish a common set of standards for field sampling, genetic analysis, data management, and legal compliance, which are presented here. We also tested the potential of ARMS for combining genetic and image-based identification methods in comparative studies of benthic diversity, as well as for detecting non-indigenous species. Results show that ARMS are suitable for monitoring hard-bottom environments as they provide genetic data that can be continuously enriched, re-analyzed, and integrated with conventional data to document benthic community composition and detect non-indigenous species. Finally, we provide guidelines to expand the network and present a sustainability plan as part of the European Marine Biological Resource Centre (www.embrc.eu).
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| 2. |
- Arvanitidis, I., et al.
(författare)
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Intrinsic reduction kinetics of cobalt- and nickel-titanates by hydrogen
- 2000
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Ingår i: Journal of Materials Research. - 0884-2914 .- 2044-5326. ; 15:2, s. 338-346
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Tidskriftsartikel (refereegranskat)abstract
- The isothermal reduction of synthetic CoTiO3 and NiTiO3 in hydrogen (1 atm) was investigated using thermogravimetric analysis technique in the temperature range, 928-1287 K (CoTiO3) and 884-1387 K (NiTiO3). Shallow beds of fine titanate powders were reduced by hydrogen at a high flow rate. Quenched samples were analyzed by scanning electron microscopy. The rates of the reaction of the titanates with H-2 were very fast during the reduction of Co2+, Ni2+, or Fe2+ ions into metals. The reduction of the remaining titanium oxide was very slow. The activation energy for the reduction of CoTiO3 by hydrogen to Co and TiO2 was evaluated to be 151 +/- 1 kJ/mol, and the activation energy for the reduction of NiTiO3 by hydrogen to Ni and TiO2 was evaluated to be 153 +/- 1 kJ/mol. The study was complemented by hydrogen reduction of synthetic TiO2 (rutile). The results were also compared with the hydrogen reduction of FeTiO3.
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| 3. |
- Meletov, Kostas P., et al.
(författare)
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High-pressure induced metastable phase in tetragonal 2D polymeric C60.
- 2001
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Ingår i: Chemical Physics Letters. - : Elsevier B.V.. - 0009-2614 .- 1873-4448. ; 341:5-6, s. 435-441
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Tidskriftsartikel (refereegranskat)abstract
- The structural stability of the tetragonal two-dimensional (2D) polymeric phase of C60 has been studied under pressure up to 24 GPa and room temperature by means of in situ Raman scattering. An irreversible transformation of the material to a new phase was observed at pressure 20 GPa. The phonon spectrum of the high-pressure phase provides a strong indication that the fullerene molecular cage is retained and therefore this phase may be related to a three-dimensional (3D) network of C60 cages. The new phase remains stable upon slow release of pressure to ambient conditions. The recovered material is metastable and transforms in air by detonation under laser irradiation to partially dimerized C60.,
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| 4. |
- Morales-Estrella, R., et al.
(författare)
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Intrinsic reduction kinetics of MoO3 by hydrogen
- 2000
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Ingår i: Zeitschrift für Metallkunde. - 0044-3093. ; 91:7, s. 589-593
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Tidskriftsartikel (refereegranskat)abstract
- The reduction kinetics of MoO3 shallow powder beds by hydrogen was investigated by isothermal and non-isothermal thermogravimetric technique. The isothermal reduction was carried out in the temperature range 823 to 973 K, whereas in the case of non-isothermal experiments, the reduction was studied by heating the sample from room temperature up to 1073 K with temperature ramps from 8 to 15 K/min. A mathematical expression based on the chemical reaction control was used to evaluate the activation energy from the non-isothermal experimental data. It was found that the chemical reaction was the rate-controlling step at the beginning of the reduction process. The activation energy for this step evaluated from the isothermal data was found to be 175 kJ/mol, which is in an excellent agreement with the value obtained from the non-isothermal data, 172 kJ/mol.
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| 5. |
- Morales, R., et al.
(författare)
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Gas-solid reactions towards new frontiers
- 2006
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Ingår i: 2006 TMS Fall Extraction and Processing Division. - 0873396332 - 9780873396332 ; , s. 97-114
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Konferensbidrag (refereegranskat)abstract
- Reactions between solids and a gas phase have many interesting theoretical aspects as well as technological applications. The present group had carried out experimental investigations as well as theoretical studies of a number of gas-solid reactions over the past decade and was able to derive interesting results. Studies of the decomposition of alkaline earth carbonates were carried out by thermogravimetric analyses. The experiments were carried out using thin powder beds as well as iso-statically pressed compacts with thermocouples embedded in the same. The investigations revealed the complexity of the reactions and the impact of the heat- and mass transfer aspects on the reaction kinetics. In the case of BaCO3, the kinetics of decomposition was complicated by the formation of a liquid phase. In the case of SrCO3, the reaction kinetics could be simulated by theoretical modeling. Gas-solid reactions were also employed as a versatile process tool towards the production of alloys and intermetallics involving transition elements by hydrogen reduction of complex oxides involving transition metals. Thin powder beds were employed to examine the micro-kinetics, while fluidized bed technique was utilized to produce bulk alloys. Preliminary correlations could be drawn between the thermodynamic stabilities of the oxides and the activation energies of chemical reduction steps. Adjusting the process parameters, products at nano-scale could be produced. The structural, mechanical and thermal properties were investigated in the case of these products. The potentialities of this method as a green route to produce industrially important alloys and intermetallics with unique properties are demonstrated.
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| 6. |
- Morales, R., et al.
(författare)
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Gas-solid reactions towards new frontiers
- 2008
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Ingår i: Mineral Processing and Extractive Metallurgy. - 0371-9553 .- 1743-2855. ; 117:2, s. 77-85
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Tidskriftsartikel (refereegranskat)abstract
- Reactions between solids and a gas phase have interesting theoretical aspects as well as technological applications. Studies of the decomposition of alkaline earth carbonates have been carried out over the past decade by thermogravimetric analyses, using thin powder beds and isostatically pressed compacts with embedded thermocouples. The investigations revealed the complexity of the reactions and the impact of heat and mass transfer on the reaction kinetics. In the case of BaCO3, the kinetics of decomposition is complicated by the formation of a liquid phase. For SrCO3, the reaction kinetics could be simulated by theoretical modelling. Gas-solid reactions were also employed as a versatile process tool towards the production of alloys and intermetallics involving transition elements by hydrogen reduction of complex oxides involving transition metals. Thin powder beds were employed to examine the microkinetics, whereas fluidised beds were utilised to produce bulk alloys. Preliminary correlations could be drawn between the thermodynamic stabilities of the oxides and the activation energies of chemical reduction. By adjusting the process parameters, nanoscale products could be produced, the structural, mechanical and thermal properties of which were investigated. The potentialities of this method as a green route to produce industrially important alloys and intermetallics with unique properties are demonstrated.
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| 7. |
- Morales, R., et al.
(författare)
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Reduction of Fe2MoO4 by hydrogen gas
- 2002
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Ingår i: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 33:4, s. 589-594
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, the reduction kinetics of iron molybdate (Fe2MoO4) by hydrogen gas was investigated by thermogravimetric analyses (TGA). Both isothermal and nonisothermal experiments were conducted. By using fine particles, very shallow powder bed, and high hydrogen flow rate, the study could be focused on the chemical reaction. The activation energy obtained from the isothermal experiments was found to be 173.5 kj/mol, which was in reasonable agreement with the value of 158.3 kj/mol obtained from the nonisothermal experiments. The reduction product was found to be an intermetallic compound, Fe2Mo, of microcrystalline structure.
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