A5077045905- Diatoms and Algae Research
- Marine and coastal ecosystems
- Protist diversity and phylogeny
- Paleontology and Stratigraphy of Fossils
- Microbial Community Ecology and Physiology
- Engineering and Materials Science Studies
- Structural Analysis and Optimization
- Marine Bivalve and Aquaculture Studies
- Marine Biology and Ecology Research
- Slime Mold and Myxomycetes Research
- Modular Robots and Swarm Intelligence
- Advanced Materials and Mechanics
- Mechanical Engineering and Vibrations Research
- Aquatic Ecosystems and Phytoplankton Dynamics
- Bacteriophages and microbial interactions
- Cephalopods and Marine Biology
- Hydrogen embrittlement and corrosion behaviors in metals
- Innovations in Concrete and Construction Materials
- Microstructure and Mechanical Properties of Steels
- Nanopore and Nanochannel Transport Studies
- Methane Hydrates and Related Phenomena
- Advanced X-ray Imaging Techniques
- Oil Spill Detection and Mitigation
- Marine and fisheries research
- Topology Optimization in Engineering
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2002-2024
Hochschule Bremerhaven
2003-2023
EDF Energy (United Kingdom)
2013-2014
Multilayer Laue lenses are volume diffraction elements for the efficient focusing of X-rays. With a new manufacturing technique that we introduced, it is possible to fabricate sufficiently high numerical aperture (NA) achieve focal spot sizes below 10 nm. The alternating layers materials form lens must span broad range thicknesses on nanometer scale necessary X-ray deflection angles required NA. This poses challenge both accuracy deposition process and control properties, which often vary...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 187:101-111 (1999) - doi:10.3354/meps187101 Colonies of Phaeocystis globosa are protected by a thin but tough skin Christian E. Hamm1,*, Doris A. Simson2, Rudolf Merkel2, Victor Smetacek1 1Alfred Wegener Institute for Polar and Research, Postfach 120161, D-27515 Bremerhaven, Germany 2Physics Department...
Monospecific diatom cultures ( Thalassiosira punctigera and Skeletonema costatum ) were incubated in rotating cylinders together with clay suspensions, present a range of concentrations (5–100 mg kaolinite L −1 as different minerals (50 kaolinite, smectite, illite, clayȁ;sized quartz powder). The addition lithogenic suspensions to accelerated the formation visible aggregates roller tanks by factor <3. Aggregate size decreased density increased proportionally amount added cultures. In...
Cellular solids are appealing for load‐bearing engineering components due to their remarkable global mechanical properties. However, complexity makes utilizing them challenging and computationally intensive. Homogenization, a common method simplifying these structures, replaces heterogeneous media with material possessing equivalent effective Despite its utility, homogenization introduces challenges, particularly the significant influence of lattice geometry on method's accuracy performance...
In both field samples and cultures the total amount of sugar carbon in colonies Phaeocystis globosa was correlated with colony surface area, suggesting a hollow structure. A conceptual model based on biochemical data assumption that mucus occurs as layer fixed thickness, irrespective size, predicts thickness is 7 μm. confocal laser scanning microscope image fluorescently labelled confirmed this view The measured contents per cell (including mucus) were constant for all sizes. Cells...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 481:41-51 (2013) - DOI: https://doi.org/10.3354/meps10227 Size and biomechanic properties of diatom frustules influence food uptake by copepods L. Friedrichs1,*, M. Hörnig1, Schulze1, A. Bertram1, S. Jansen1, C. Hamm1,2 1Alfred-Wegener-Institute for Polar Research, Am Handelshafen 12, 27570 Bremerhaven,...
Summary Exact geometric description, numerical analysis and comparison of microscopic objects such as the frustules diatoms are increasing importance in basic research (e.g. functional morphology, taxonomy biogeochemistry). Similarly, applied product development fields lightweight construction nanotechnology can benefit from machine‐readable data structures. This paper presents a new method to combine scanning electron microscopy confocal laser generate exact three‐dimensional models diatom...
Lightweight structures are susceptible to vibration due their reduced mass. However, conventionally used techniques avoid high amplitudes (such as increasing the mass and/or applying damping mechanisms) contradictory original goal of designing a lightweight structure. An increase eigenfrequencies above external, exciting frequencies helps prevent resonance phenomena. Here, we use combined design and optimisation method generate irregular lattice investigate potential reaching much higher...
Diatoms have delicate and complex shells showing different lightweight design principles that already been applied to technical products improving the mechanical properties. In addition, diatom inspired structures are expected significantly affect vibration characteristics, i.e., eigenfrequencies. Directed eigenfrequency shifts of great interest for many applications prevent undesired high amplitudes. Therefore, numerous dome primarily based on combs, ribs, bulging patterns were constructed...
In both field samples and cultures the total amount of sugar carbon in colonies Phaeocystis globosa was correlated with colony surface area, suggesting a hollow structure. A conceptual model based on biochemical data assumption that mucus occurs as layer fixed thickness, irrespective size, predicts thickness is 7 μm. confocal laser scanning microscope image fluorescently labelled confirmed this view The measured contents per cell (including mucus) were constant for all sizes. Cells...
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 209:55-69 (2001) - doi:10.3354/meps209055 On trophic fate of Phaeocystis pouchetii. VII. Sterols and fatty acids reveal sedimentation P. pouchetii-derived organic matter krill fecal strings Christian Hamm1,*, Marit Reigstad2, Wexels Riser2, Anneke Mühlebach1, Paul Wassmann2 1Alfred-Wegener Institute for Polar...
A significant fraction of ferrite has been identified in a 321 grade austenitic stainless steel the solution heat treated condition. The microstructures were analysed using electron backscatter diffraction, energy dispersive X-ray spectroscopy and diffraction (XRD) stability investigated treatments tube furnace, dilatometry high temperature XRD. dissolved ∼800°C, then formed again on cooling at temperatures under 200°C. Thermodynamic predictions showed content room equilibrium conditions,...
Samples of 321 stainless steel from both the parent and welded section a thin tube were subjected to accelerated ageing simulate long term service conditions in an advanced gas cooled reactor (AGR) power plant. The initial condition metal showed duplex microstructure with approximately 50 ferrite austenite. weld three distinct matrix phases, austenite, delta ferrite. This result was surprising as expected be fully austenitic austenite+delta weldment. intermetallic sigma phase formed during...
Diatoms, a class of aquatic autotrophic microorganisms, are characterized by silicified exoskeletons with highly complex architectures. These morphologies have been shaped the selection pressure that organisms subjected to during their evolutionary history. Two properties which likely contributed success current diatom species lightweightness and structural strength. Thousands present in water bodies today, although each has its unique shell architecture, strategy is common across uneven...
Abstract Lightweight structures are widely used across different industry sectors. However, they get easily excited by external influences, such as vibrations. Undesired high vibration amplitudes can be avoided shifting the structural eigenfrequencies, which achieved adapting design considering optimisation procedures and primarily inspired diatoms. This has been applied to development process of a girder structure installed in synchrotron radiation facility support heavy magnets other...