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  • 2020-2024  (11)
  • 1
    Online Resource
    Online Resource
    Porous Metals and Metallic Foams : MetFoam 2023. (2024)
    Millersville :Materials Research Forum LLC,
    Details
    Keywords: Electronic books.
    Description / Table of Contents: The book focuses on the production methods, properties and applications of functional and lightweight porous/cellular metallic materials.
    Type of Medium: Online Resource
    Pages: 1 online resource (66 pages)
    Edition: 1st ed.
    ISBN: 9781644903094
    Series Statement: Materials Research Proceedings Series ; v.39
    URL: https://ebookcentral.proquest.com/lib/geomar/detail.action?docID=31260938
    Language: English
    Note: Intro -- front matter -- Table of Contents -- Editorial -- Committees -- 1 -- Surface Emissivity Effect on the Performance of Composite Metal Foam against Torch Fire Environment -- 1. Introduction -- 2. Materials and processing -- 3. Experimental procedure -- 3.1 Emissivity measurements -- 3.1.1 Test set up and measurement procedure for CMF matrix emissivity -- 3.1.2 Measurement procedure for sphere emissivity -- 3.1.3 Effects of sphere curvature on emissivity -- 4. Results and discussions -- 4.1 Matrix emissivity -- 4.2 Sphere emissivity results -- 4.3 Rule of mixtures -- Conclusion -- Acknowledgements -- References -- 2 -- Characterization of 316L Stainless Steel Composite Metal Foam Joined by Solid-State Welding Technique -- 1. Introduction -- 2. Experimental -- 2.1 Materials and processing -- 2.2 Tensile testing -- 3. Results and discussion -- 3.1 Preliminary structural observation -- 3.2 Mechanical behavior -- Conclusions -- Acknowledgements -- References -- 3 -- Thermal Conductivity of Steel-Steel Composite Metal Foam through Computational Modeling -- Introduction -- Computational modeling -- Results and discussions -- Conclusion -- Acknowledgment -- References -- 4 -- Custom Design to the Application of Open-Cellular Metal Structures -- Introduction -- Design and Process Setup -- Process - Investment Casting -- Materials -- Experimental Setup -- Experimental -- Summery and outlook -- Acknowledgements -- References -- 5 -- Analytical Determination of the Geometrical Properties of Open-Celled Metal Foams Under Compression -- Introduction -- Model parameters -- Adjusted three-strut RUC model -- Model application and validation -- Summary -- References -- 6 -- Numerical Investigation on Deformation Behavior of Aluminium Foams with in situ Composite Particles -- Introduction -- Numerical methodology -- Results and discussions -- Conclusions. , References -- 7 -- Opportunities of Metal Structures in Cooling Systems -- Introduction -- Cooling of high-performance electronics in the mobility sector -- Evaluation of the thermal behavior of power modules using numerical simulation -- Optimizing cellular metal structures to create maximum cooling efficiency -- Parameter determination for the structure optimization -- Life Cycle Assessment (LCA) and recycling of metal foam-based cooling structures -- Summary -- References -- back matter -- Keyword Index.
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  • 2
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    Investigation of geoid gradients estimated from simulated SWOT altimeter data (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-29
    Description: The recent Surface Water Ocean Topography (SWOT) altimeter mission measures two-dimensional SSHs along two 50-km-wide swaths and one-dimensional SSHs along the nadir track, providing a significant opportunity to improve the accuracy and resolution of geoid gradients essential for marine gravity modeling. This study investigates the accuracy of determining north and east components of geoid gradients using simulated SWOT SSHs in the northern part of the South China Sea. SWOT SSH data were simulated using ocean depths from multi-beam and the GEBCO_2020 bathymetry model and the DTU mean sea surface. According to the unique characteristic of high-resolution two-dimensional SWOT SSH observations, we developed a new method that determines north and east components of geoid gradient at the grid point based on geoid gradients computed in along-, cross- and middle-track directions using the least-squares adjustment (LSA). For comparison purpose, the gradient components were also computed using the least-squares collocation (LSC). The accuracy of determined gradient components is assessed using the quasi-true values of gradients computed by numerical differentiations from the SWOT simulation model. The RMSE results are 0.51 (0.42) microrad and 1.12 (0.91) microrad for LSA (LSC) estimates of north and east components, respectively, in the study area. The results indicate that the LSA gradient solution is computationally efficient and compatible with those by the LSC. The SWOT mission significantly improves the accuracy of estimated gradient components when compared to Jason-2 and Cryosat-2.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 3
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    Bathymetry changes from ICESAT-2 -A case story from Moreton Bay Australia (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-07-04
    Description: The bathymetry of coastal bay environments, like Moreton Bay around Brisbane in eastern Australia, is constantly reworked because of changes in the patterns of energy dispersal and related sediment transport pathways. Updated and accurate bathymetric models are a crucial component for scientific, environmental, and ship safety studies.NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) was launched in September 2018 and carries a single instrument, ATLAS (Advanced Topographic Laser Altimeter System). ATLAS is a green wavelength, photon-counting lidar, enabling global measurement and monitoring of elevation with a primary science focus on the cryosphere. However, ATLAS’s green laser frequently penetrates the air–water interface, and under the right conditions and in shallow waters (〈40 m), these photons are reflected back to ATLAS after interaction with the ocean bottom.An Australian Research Council funded research project “Enhancing marine bathymetry using new-generation satellite sensors” commenced in 2022. We present the first results from this project on the use of ICESAT-2 along selected 91-day repeat tracks across Moreton Bay to investigate changes in bathymetry over the past 4 years. Moreton Bay has had significant changes in bathymetry with time, but significant suspended sediment creates problems for ICESat-2 photons to propagate through the water column.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 4
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    Arctic ocean tidal constituents atlas (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-29
    Description: Ocean tides are a vital component of global ocean circulation, with their role in the Arctic Ocean being crucial for ocean and sea ice dynamics. Recently, significant advances have been made in global ocean tide models, however, difficulties remain in the coastal regions as well as in the higher latitudes. The latter is related to the poorly resolved bottom topography, the influence of sea ice and limited regular satellite altimetry measurements. Although modelling efforts are attempting to improve our ocean tide estimates in the Arctic Ocean, the tidal in-situ network is an additional limiting factor in this region. In-situ measurements from tide gauges or ocean bottom pressure sensors are crucial sources of information that can be used to understand the spatial variability of tides as well as validate the advances made in modelled estimates. However, globally in-situ tidal constituent databases contain a limited number of observations with, for example, TICON-3 containing 111 above 60°N and 21 above 70°N with the distribution of these measurements mainly being around North America. This abstract presents the results of a concerted effort to produce a harmonised dataset of tidal constituents in the Arctic region. This dataset combines in-situ measurements from tide gauges, ocean bottom pressure sensors and GNSS reflectometry, which results in approximately 691 measurements above 60°N and 313 above 70°N with a much greater spatial distribution across the full Arctic ocean. The resultant dataset is quality assessed and compared to recent tide models to determine the reliability of the different data sources used.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 5
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    High-resolution modeling of dynamic vertical land movement in the Northern Hemisphere due to changing ice sheets and glaciers (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-07-20
    Description: The impact of elastic vertical land movement (VLM) on relative sea levels along the world's coastlines is significant. In Northern Europe, VLM is mainly due to the effect of Glacial Isostatic Adjustment (GIA). However, the rapid melting of ice in the Arctic is causing a substantial elastic uplift with both a local, but also a long-range footprint of 1000-3000 km from the point of ice loss. When VLM estimates from GNSS are unavailable, sea-level studies based on tide gauges often rely on a GIA-only VLM model to correct any ongoing uplift, but in Arctic regions, this can lead to underestimation of the uplift or overestimation of the absolute sea-level change due to significant changes in present-day ice loading (PDIL). Here, a high-resolution time-varying elastic VLM model (5x5 km) is developed from high-resolution estimates of glacial and Greenland Ice Sheet mass balance is presented. The elastic VLM model is combined with a GIA model to create a complete VLM model that is comparable with GNSS-measured VLM rates (in a center of mass frame). Additionally, far-field elastic effects from the Antarctic and Terrestrial Water Storage are included to create a complete vertical deformation map for the Northern Hemisphere, that can complement sea level studies in areas with few or no GNSS measurements.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 6
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    The DTU21 Global marine gravity field based on existing altimetric Geodetic Missions and outlook towards the use of SWOT (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-07-31
    Description: The newest DTU global high-resolution global marine free air gravity field called DTU21 is presented in this presentation and the first evaluation against marine and airborne gravity is performed. A total of 14 years from geodetic missions including (7 years of Cryosat-2 (369 days repeat mission) as well as 3 years of Jason-1+2 end-of-life missions and 4 years of SARA/AltiKa drifting geodetic mission). Older geodetic missions (ERS-1 and GEOSAT) are now nearly retired. All Geodetic missions have been fully retracked using the 2-pass retracker developed by Sandwell and Smith, (2005) to increase the range precision. Subsequently, we derive 2-Hz altimetric observations from the 20/40 Hz retracked data using the Parks McClellan filter to avoid spectral leakage degrading the 10-40 km wavelength which is an effect of the box filter normally used to compute 1 Hz data. In the Arctic Ocean, we will present results from several new developments in high-resolution gravity field modelling. One is a new dual-pass retracking of SARAL/AltiKa together with a new physical retracking system for Cryosat-2 derived at ESA called SAMOSA+. This was retracked using the ESA GPOD service. A new medium wavelength correction based on altimetry and GOCE has been introduced to deal with problems in the older remove restore technology based on EGM2008. This is particularly important for Cryosat-2 due to its ability of provide new accurate sea surface height information for gravity field determination all the way up to 88N where no altimeters have measured before.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 7
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    Global mean sea level acceleration estimate from 30 years of satellite altimetry from multiple satellite time series (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-16
    Description: For more than 30 years, altimetry satellites have consistently measured the sea surface height from space. These measurements allow us to analyze both temporally and spatial global sea-level changes over the last 3 decades. In recent years, the scientific consensus is that the global mean sea level is increasing by approximately 0.1 mm/yr〈sup〉2〈/sup〉. This acceleration is usually calculated from the TPJ satellite missions (TOPEX/Poseidon, Jason-1, Jason-2, Jason-3). We recompute the acceleration up to year 2022 from TPJ and consolidated this acceleration with independent altimetry data from the associated ESA sequence of satellite missions (ERS-1, ERS-2, Envisat and CryoSat-2) from 1991 to 2022. The analysis is based on monthly gridded data using both the TPJ and ESA time series. We investigate the difference in the time-series/trend and acceleration in relation to the recent discussion on mis-closure of the sea level budget since 2015, both globally within 66N but also for the greater spatial extent of the ESA data set with the inclusion of the Arctic Ocean up to 82 degrees north.
    Language: English
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  • 8
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    Rethinking the modelling of the mean sea level in the era of climate change (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-06-16
    Description: Since the beginning of the precision satellite altimeter era in the early 1990s, efforts have been focused on computing the mean height of the ocean surface for use in various geodetic and oceanographic studies. With 30 years of satellite measurements now available, it is time to rethink the modeling of the mean sea surface (MSS) in the era of climate change.Today, there are places in the ocean that are 15 cm higher than they were 30 years ago, and today the average error is around 5 cm for conventional MSS models.We propose that linear sea level changes be used in a new definition of the MSS correction which is tied to a particular date in time. For example, one definition could be:MSS(ϕ,λ,t)= MSS(ϕ,λ,2003.0)+(MSS) ̇(ϕ,λ)(t-2003.0). Where MSS(ϕ,λ,2003.0) is the height of the sea surface in 2003.0 and the epoch used for the most common MSS models, e.g., the DTU and CLS MSS models. (MSS) ̇(ϕ,λ) is the linear rate of change of the sea surface height averaged over 30 years.We will present the testing of a new mean sea surface correction and find the performance to be significant for recent satellites like Jason-3 and Sentinel 3 and 6. It reduces the mean offset for these recent satellites wrt with respect to conventional satellites, but it also performs significantly better in reducing the spatial variability.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 9
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    Polar ocean tides revisited (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-08-09
    Description: Polar oceans have generally been harder to determine from satellite altimetry because the regions outside the 66 parallel has traditionally only been surveyed satellites in sun-sun-synchronous orbits. With Cryosat-2 this has changed. However, the satellite poses a number of challenges to tidal analysis because of its long ground-track repeat period (368 days) and its diverse measurement modes, low-rate mode (LRM) over the ocean and synthetic aperture radar interferometric mode (SARin) over ice surfaces and parts of the ocean. The SAMOSA+ physical retracker was developed to process the Cryosat-2 data across measurement modes and hereby enables the determination of the sea state bias. This way it provides more stable sea level estimates compared with traditional empirical retrackers used in the Polar Ocean. Nearly 10 years of Cryosat-2 data have been analyzed for residual ocean tides to the FES2014 ocean tide model in the Arctic Ocean and Antarctic Ocean using the response formalism. We use data from the near monthly repeat pattern of C2 as this has a favorable alias period for most major constituents. Using this information, the long wavelength corrections to the major astronomical constituents M2, S2, K2, N2, K1, O1, P1, and Q1 tides have been mapped for both the ocean and floating ice shelves domains. In addition, several smaller third, fourth and sixth diurnal tides have been determined. Some of these small compound/over tides does show small but consistent signal across regions like the Weddell sea (South Atlantic) and in the Baffin Bay between Greenland and Canada.
    Language: English
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  • 10
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    Global and regional ocean mass change observed and reconstructed for 20 years of GRACE and GRACE FollowOn observations (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-08-31
    Description: The ocean mass budget plays a crucial role in predicting future changes in ocean mass and sea level. In recent efforts to reconcile observations from GRACE and GRACE-Follow On satellites with steric-corrected altimetry and models of contributions from land and ice a discrepancy in the mass budget has been reported (Wang et al, 2022; Barnoud et al, 2022), in particular in the period following the launch of GRACE-Follow On. In this study, we aim to compare 20 years of GRACE-observed mass changes with steric-corrected altimetry and GRD-induced sea level changes resulting from landmass changes. To accomplish this, we produce monthly 3D global mass change products with a spatial resolution of 0.5 degrees, covering the period from 2003 to 2022. We improve the processing steps for steric-corrected satellite altimetry by accounting for ocean bottom deformation, removing the global mean contribution of halosteric sea level change, and replacing the radiometer-based wet tropospheric correction with a model-based correction. Our results indicate that both the steric-corrected altimetry and ocean mass reconstruction from GRD-induced sea level change is in agreement with the GRACE observations on both long-term and seasonal time scales and regional scales. We also find that a recent slowdown in GRACE-observed mass change during the GRACE-FO period can be attributed to terrestrial water storage variability driven by a long phase of La Nina and a deceleration in the mass loss of Greenland and Antarctic ice sheets.
    Language: English
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