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- Hansen, Steffen Foss, et al.
(author)
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Nanotechnology meets circular economy
- 2022
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In: Nature Nanotechnology. - : Springer Science and Business Media LLC. - 1748-3387 .- 1748-3395. ; 17:7, s. 682-685
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Journal article (other academic/artistic)
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| 3. |
- Hansen, Steffen Foss, et al.
(author)
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To be or not to be a nanomaterial
- 2022
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In: Journal of Nanoparticle Research. - : Springer Science and Business Media LLC. - 1388-0764 .- 1572-896X. ; 24:12
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Journal article (peer-reviewed)abstract
- In early 2021, the new definition of the term “nanomaterial” proposed by the European Commission (EC) was subject to a stakeholder consultation and in June 2022, the EC published its updated definition. Based on an independent analysis of the different versions of the definition and the results of the stakeholder consultation, the aim of this paper is to identify key aspects to be considered when deciding whether a material should be regarded as a nanomaterial. More than 130 comments submitted during the stakeholder consultation by various organizations, companies, citizens, and authorities were analyzed. We find that the introduction of new terms such as “solid particles” has added clarity to terms used in the former definition. Our analysis shows that stakeholders seemed inclined to maintain the default number-based 50% threshold value, but were opposed to (1) the possible flexibility of varying the threshold in specific sectorial legislation, (2) the default inclusion of carbonaceous materials < 1 nm, and (3) the use of volume specific surface area (VSSA) other than for excluding materials from being defined as nanomaterials. Overall, we find that the updated definition addresses many of the limitations of the former definition. However, the updated definition also creates new challenges that will have to be addressed via development of new regulatory guidance. Apart from the relatively minor change of the VSSA threshold from 5 to 6 m2/cm3, it generally seems that no arguments from the stakeholder consultation made the EC reconsider its position. Graphical Abstract: [Figure not available: see fulltext.].
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| 4. |
- Nielsen, Maria, et al.
(author)
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Nanomaterials in the European chemicals legislation-methodological challenges for registration and environmental safety assessment
- 2021
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In: Environmental Science: Nano. - : Royal Society of Chemistry. - 2051-8153 .- 2051-8161. ; 8:3, s. 731-747
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Journal article (peer-reviewed)abstract
- In the European Union the Annexes of its chemical legislation (REACH) were revised and now clarify the technical data requirements for nanomaterials (NMs). These new provisions, effective from January 1, 2020, introduce requirements for manufacturers, importers and downstream users regarding registration and safety assessment of NMs. This study aims to assess the availability and suitability of methods needed to comply with the new regulatory provisions on NMs for physico-chemical characterisation and environmental fate and effects. The scientific literature and relevant test guideline frameworks were reviewed to identify applicable methods. These were subsequently evaluated and categorised as either: 'internationally accepted test guideline or standard (TGS)', 'internationally accepted test guideline or standard under development (TGSUD)', 'established as standard methods in scientific literature (SCI)', 'other methods and/or more research needed (O)' or 'no method (N)'. We find that 80% of the information requirements and a bit more than 40% of the waiving criteria in the new REACH Annexes are supported by methods that are available as TGS, TGSUD or SCI. Most of the relevant methods in the scientific literature are included in recent OECD guidance documents or ECHA guidance. We recommend that a targeted effort is made to develop protocols and guidelines for methods to determine NM adsorption/desorption, degradation, exposure scenarios and ability to cross biological membranes. Here methods to fulfil the information requirements and waiving criteria are currently lacking. Furthermore, we recommend that increasing attention is directed towards regulatory reliability and relevance of the information that is submitted by the registrants.
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- Thorsen, Lauge S., et al.
(author)
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High pressure oxidation of NH3/n-heptane mixtures
- 2023
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In: Combustion and Flame. - 0010-2180. ; 254
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Journal article (peer-reviewed)abstract
- Oxidation of NH3/n-heptane mixtures at pressures up to 100 atm and temperatures of 400–900 K was characterized experimentally in a laminar flow reactor and a jet-stirred reactor. A detailed chemical kinetic model was developed, updating the hydrogen and amine subsets and introducing a subset for the chemical coupling with emphasis on the NH2+n-heptane reaction. The kinetic model provided a good prediction of the ignition delay times measured in a rapid compression machine by Yu et al. (Combust. Flame 217 (2020) 2–11) as well as the high pressure experimental data obtained in the present work. The results show that it is important to include updated rate constants for NH2 + HO2 and NH2 + n-C7H16 to obtain reliable predictions for ignition and oxidation of NH3/n-heptane mixtures at high pressure. The effectiveness of implementing analogy rules for determining the rate constant of the key reaction NH2 + n-C7H16 was confirmed by the observed results.
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