Состав углеводородов в продуктах синтеза из окиси углерода и водяного пара

Исследован состав продукта синтеза из окиси углерода и водяного пара методами газожидкостной хроматографии. Показано, что продукт представлен смесью углеводородов C5-C20, спиртами и кислотами состава C1-C12; наряду с н-парафинами и а-олефинами присутствуют соединения изостроения. Определен индивидуальный состав фракции С5-С8, где обнаружено 83 компонента

Action needed for the EU Common Agricultural Policy to address sustainability challenges

Abstract Making agriculture sustainable is a global challenge. In the European Union (EU), the Common Agricultural Policy (CAP) is failing with respect to biodiversity, climate, soil, land degradation as well as socio-economic challenges. The European Commission's proposal for a CAP post-2020 provides a scope for enhanced sustainability. However, it also allows Member States to choose low-ambition implementation pathways. It therefore remains essential to address citizens' demands for sustainable agriculture and rectify systemic weaknesses in the CAP, using the full breadth of available scientific evidence and knowledge. Concerned about current attempts to dilute the environmental ambition of the future CAP, and the lack of concrete proposals for improving the CAP in the draft of the European Green Deal, we call on the European Parliament, Council and Commission to adopt 10 urgent action points for delivering sustainable food production, biodiversity conservation and climate mitigation. Knowledge is available to help moving towards evidence-based, sustainable European agriculture that can benefit people, nature and their joint futures. The statements made in this article have the broad support of the scientific community, as expressed by above 3,600 signatories to the preprint version of this manuscript. The list can be found here (https://doi.org/10.5281/zenodo.3685632). A free Plain Language Summary can be found within the Supporting Information of this article.Peer reviewe

Additive manufacturing of high performance oxide ceramics via selective laser melting

Oxide ceramics such as Alumina (Al2O3) and Zirconia (ZrO2) are widely utilized in various engineering fields due to their excellent mechanical properties along with outstanding thermal and wear resistance. Their biocompatibility, strength and esthetics also qualify these oxide ceramics for medical applications. Limitations to the geometry and shrinking during the conventional sintering process often prevent utilization of these high-strength ceramics in various applications. These limitations may be overcome by employment of Additive Manufacturing (AM) techniques, allowing for layer-wise generation of complex-shaped components directly from CAD data. The present work studies AM of ceramic specimens, based on Al2O3/ZrO2 powder by means of Selective Laser Melting (SLM). Towards this end, the powder material is qualified in terms of flowing ability and optical characteristics, aiming at developing a new process in which pure ceramics are completely melted by a laser beam, yielding net-shaped specimens of almost 100% densities without any post processing. Formation of cracks is suppressed by high-temperature preheating at which new preheating concepts are developed and compared in terms of thermoanalyses and the resulting property profiles. Employing the eutectic Al2O3/ZrO2 mixture ratio results in a fine-grained microstructures and flexural strengths of up to 1150 MPa. Dominating effects of high-temperature SLM on the surface quality are analyzed and filigree structures of < 300 µm wall thickness and a profile roughness of Rz < 70 µm are achieved. For demonstration purposes fully ceramic dental restorations have been manufactured, highlighting the possibilities of manufacturing individual complex shaped high-strength ceramic components by means of SLM

Additive manufacturing of high performance oxide ceramics via selective laser melting

Oxide ceramics such as Alumina (Al2O3) and Zirconia (ZrO2) are widely utilized in various engineering fields due to their excellent mechanical properties along with outstanding thermal and wear resistance. Their biocompatibility, strength and esthetics also qualify these oxide ceramics for medical applications. Limitations to the geometry and shrinking during the conventional sintering process often prevent utilization of these high-strength ceramics in various applications. These limitations may be overcome by employment of Additive Manufacturing (AM) techniques, allowing for layer-wise generation of complex-shaped components directly from CAD data. The present work studies AM of ceramic specimens, based on Al2O3/ZrO2 powder by means of Selective Laser Melting (SLM). Towards this end, the powder material is qualified in terms of flowing ability and optical characteristics, aiming at developing a new process in which pure ceramics are completely melted by a laser beam, yielding net-shaped specimens of almost 100% densities without any post processing. Formation of cracks is suppressed by high-temperature preheating at which new preheating concepts are developed and compared in terms of thermoanalyses and the resulting property profiles. Employing the eutectic Al2O3/ZrO2 mixture ratio results in a fine-grained microstructures and flexural strengths of up to 1150 MPa. Dominating effects of high-temperature SLM on the surface quality are analyzed and filigree structures of < 300 µm wall thickness and a profile roughness of Rz < 70 µm are achieved. For demonstration purposes fully ceramic dental restorations have been manufactured, highlighting the possibilities of manufacturing individual complex shaped high-strength ceramic components by means of SLM

Vorrichtung und Verfahren zur generativen Bauteilfertigung

Source: WO15003804A1 [EN] The invention relates to a device and method for laser-based, generative component production. The device comprises a processing head (1), with which a plurality of laser beams, separated from each other, are directed adjacent to each other and/or partially overlapping on the processing plane. The processing head (1) is moved by a movement apparatus (9) over the processing plane, while the laser beams, which are separated from each other, are modulated in intensity, independently of one another, in order to obtain the desired exposure geometry. The laser power and the dimensional size of the generative production can be cost-effectively scaled by the device and the related method according to the invention