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| 42. |
- Gu, Y. W., et al.
(författare)
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Solid state synthesis of nanocrystalline and/or amorphous 50Ni-50Ti alloy
- 2005
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 392:1-2, s. 222-228
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Tidskriftsartikel (refereegranskat)abstract
- A nanocrystalline/amorphous 50Ni-50Ti alloy was produced by solid state synthesis via mechanical alloying from elemental Ti and Ni powders. Using X-ray diffraction analysis and transmission electron microscopy techniques, a mechanically induced solid state reaction of 50Ni-50Ti was investigated. Results showed that nanocrystalline and amorphous Ni-Ti phases were obtained after mechanical alloying. The mechanical alloying of 50Ni-50Ti for 270 ks led to the formation of f.c.c. Ni(Ti) solid solution, characterized by a lattice parameter of 0.3558 nm, crystallite size of 14 nm and lattice strain of 0.98%. The particle size decreased with increasing milling time. The crystallite size of mechanically alloyed 50Ni-50Ti powders was substantially refined as the milling proceeded and the lattice strain increased with the milling time. The steady-state crystallite size was approximately 10-15 nm. The internal lattice strain in Ni-Ti alloy led to the disordering and the subsequent formation of amorphous alloy during mechanical alloying. After heat treatment at 1100 °C, the as-milled powders transformed into B2-NiTi phase and a small amount of Ti2Ni phase. © 2004 Elsevier B.V. All rights reserved.
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| 47. |
- Leebens-Mack, James H., et al.
(författare)
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One thousand plant transcriptomes and the phylogenomics of green plants
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 574:7780, s. 679-
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Tidskriftsartikel (refereegranskat)abstract
- Green plants (Viridiplantae) include around 450,000-500,000 species(1,2) of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life.
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| 50. |
- Pelkmans, L., et al.
(författare)
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Monitoring the Impact of Sustainability Certification in Relation to Biomass Use for Energy
- 2012
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Ingår i: EUBCE 2012 proceedings. - 9788889407547 ; , s. 2013-2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Since the public has expressed concern about unintended consequences associated with potentially unsustainable biomass production and use for energy (or biofuels), producers of biomass feedstocks in the private sector as well as governmental and non-governmental organisations have initiated many generally unlinked efforts to define 'sustainable' bioenergy production and supply chains. These 'sustainability' standards may be implemented through certification systems involving 3rd party audit, and influence production systems and trade of bioenergy products from producers to consumers of ‘green' energy. At present numerous biomass and biofuel sustainability certification systems are being developed or implemented by a variety of private and public organisations. Systems are applicable to different feedstock production sectors (forests, agricultural crops), different bioenergy products (relatively unprocessed forest residues, ethanol, biodiesel, electricity), and whole or segments of supply chains (production system, chain of custody from growers to energy consumers). It is expected that such a wide range of systems, developed largely without coordination among the organisations involved, could be problematic for all stakeholders along the supply chain in individual sectors and for those involved in deployment of bioenergy systems globally. These are individual feedstock producers, companies and commodity sectors that must comply with these systems either to maintain market access and share or to comply with legislative mandates, and also consumers who prefer to purchase certified green energy, and regulatory agencies and local to national governments that may be involved in enforcing sustainability standards. The potential for confusion among the actors, depression of markets, and unnecessary restrictions on sustainable trade seems high. Within IEA Bioenergy a strategic study was initiated between Task 40, Task 43 and Task 38 to monitor the actual implementation process of sustainability certification of bioenergy, evaluate how stakeholders are affected by certification initiatives, quantify the anticipated impact on worldwide bioenergy trade, assess the level of coordination among schemes, and make recommendations to remove barriers which may depress markets and reduce sustainable trade. Interaction with different stakeholder groups is one of the main objectives of this study, so we anticipate the recommendations being representative of the whole bioenergy certification sector and therefore having high potential to improve an otherwise uncoordinated interest in ensuring bioenergy trade is sustainable.
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