Liquid-Phase Sintering of Iron Aluminide-Bonded Ceramics

Abstract Iron aluminide intermetallics exhibit excellent oxidation and sulfidation resistance and are therefore considered as the matrix in metal matrix composites, or the binder in hard metals or cermets. In this paper n e discuss the processing and properties of liquid-phase sintered iron aluminide-bonded ceramics. It is found that ceramics such as TiB2. ZrB?, Tic, and WC may all be liquid phasesintered. Nearly complete densification is achie% ed for ceramic volume fractions ranging up to 60%. Dependins on the composition, room temperature three point-bend strengths and fracture toughnesses reaching 1500 MPa and 30 MPa mil2, respectively, have been found. Since the processing was carried out in a very simple manner, optimized processing is likely to result in further improvements

USING EARTH OBSERVATION TO SUPPORT FIRST AID RESPONSE IN CRISIS SITUATIONS– LESSONS LEARNED FROM THE EARTHQUAKE IN TÜRKIYE/SYRIA (2023)

In the early morning hours on Tuesday, February 6, 2023, the southern part of Türkiye was struck by two large and several smaller earthquakes, causing destruction and casualties over a remarkably large area. In such cases, quick response and well-informed coordination is a key factor to successful first aid responses since damage and the number of people buried or in need often remain unclear in the hours after the disaster. The German Aerospace Center (DLR) responded to the earthquake by rapidly providing a number of information products, all above very high-resolution imagery in an easy-to-use web-based application. Next to satellite and drone imagery, damage information and pre-disaster imagery were provided to the users. Drone imagery was acquired in person for Kirikhan, a city in the south of the disaster area. Access to the viewer was granted to authorized users from public authorities, humanitarian aid organisations, and research institutes. Furthermore, DLR generated information products in the fields of settlement pattern, AI based damage assessment and tectonic movements. These data, as scientifically significant as they are, were not part of the web viewer. Within this paper, the reasons will be assessed as well as the general workflow of the activation. The paper will also discuss what steps need to be taken to ensure research outcomes being integrated into information products for users in future and how to prepare for the next disaster to still ensure a quick response but with an enriched product suite

Cumulative effects of policy and management actions on ecosystem services. Challenges and methodological approaches in The Future Okavango project

The Okavango Basin encompasses a wide range of ecosystems and, corresponding to its extension across Angola, Botswana and Namibia, a multitude of communities with diverse socio-economic contexts, that in turn are determined both, by local traditions and regional and national policies. With the river acting as a connecting element, managing the use of natural resources under consideration of conservation issues is a challenging task. The interdisciplinary research project "The Future Okavango" (TFO) aims at contributing to integrated, sustainable land management by providing scientific support to stakeholders from local to national levels. The region under investigation, a system of woodlands, floodplains and extended wetlands is of crucial global importance for biological diversity. Simultaneously it is threatened by rapid transformation through climate change, population growth and anthropogenic over-utilization of natural resources, which may amplify land and water conflicts. The project adopts an approach of mapping and valorising a set of representative ecosystem services and the underlying ecosystem functions. Since these are provided at different spatial and temporal scales, and can show varying properties at different scales, a multi-scale approach is required that covers services from the plot-scale to the full Okavango Basin area. Besides the issue of multi-scale variation, cumulative effects may occur between different processes in both, the spatial and temporal dimension, and causing off-site effects or services being partially determined by past processes. In this paper we identify key issues in the assessment process in a wider conceptual context and describe mapping and assessment procedures. Finally, we introduce the concepts utilized to integrate sectorial assessments of ecosystem services and provide an example of an integrated assessment for a theoretical case study in Northern Namibia

Ambient Tohig Temperature Fracture Tougure%

Boron-containing molybdenum silicides have been the focus ofsigP`I%y3 research of late due to their potentially superior lowtemperature "pest" resistance andhigPTqP%y3qTj`% oxidation resistance comparable to that of MoSi 2 -based silicides; however, like many ordered intermetallics, they areplagEx by poor ductility andtoug'TxP properties. Of the various multiphase Mo--Si--B intermetallic systems available, alloys with compositions of Mo--12Si--8.5B (at.%), which contain Mo, Mo 3 Si, and T2 phases, are anticipated to havehig%' toug'EI3%y because of the presence of the relatively ductile Mo phase. In this study, we examine the ambient tohig (1300 # C) temperature fracture tougure% (R-curve) andfatig"%y3T` gtig characteristics of Mo-12Si-8.5B, with the objective of discerning the salient mechanismsgechanis crackgack%3 It is found that this alloy displays a relativelyhig intrinsic (crack-initiation)tougk-in at 800 up to 1200 # C(#10 MPa p m), but only limitedextrinsic R-curve(crack-gExP%y tougc ness.Althoug the lack of extrinsictougsic%' mechanisms is not necessarily beneficial to quasi-static properties, it does imply in a brittle material that it should show only minimal susceptibility to premature failure byfatigxx as is indeed observed at temperatures from ambient to 1300 # C. Of particular sigicular% is that both the fracture tougure% and the threshold stress intensity for fatigT are increased withincreasing temperature over thisrangx This remarkable property is related to a variety oftougjq%yx mechanisms that become active at elevated temperatures, specificallyinvolving cracktrapping by the a-Mo phase and extensive microcracking primarily in the Mo 5 SiB 2 phase. Published by Elsevier Science Ltd