scholarly journals Understanding the Impact of Boundary and Initial Condition Errors on the Solution to a Thermal Diffusivity Inverse Problem

2011 ◽  
Vol 4 ◽  
pp. 156-174 ◽  
Author(s):  
Xiaojing Fu ◽  
◽  
Brian Leventhal
Keyword(s):  
Inverse Problem ◽  
Thermal Diffusivity ◽  
Initial Condition ◽  
The Impact

Role of initial condition and parametric uncertainty in a severe hailstorm forecast

2021 ◽  
Author(s):  
Patrick Kuntze ◽  
Annette Miltenberger ◽  
Corinna Hoose ◽  
Michael Kunz
Keyword(s):  
Initial Conditions ◽  
Weather Prediction ◽  
Parametric Uncertainty ◽  
Radar Data ◽  
Cloud Microphysics ◽  
Initial Condition ◽  
Relative Contribution ◽  
Cloud Properties ◽  
Set Up ◽  
The Impact

<p>Forecasting high impact weather events is a major challenge for numerical weather prediction. Initial condition uncertainty plays a major role but so potentially do uncertainties arising from the representation of physical processes, e.g. cloud microphysics. In this project, we investigate the impact of these uncertainties for the forecast of cloud properties, precipitation and hail of a selected severe convective storm over South-Eastern Germany.<br>To investigate the joint impact of initial condition and parametric uncertainty a large ensemble including perturbed initial conditions and systematic variations in several cloud microphysical parameters is conducted with the ICON model (at 1 km grid-spacing). The comparison of the baseline, unperturbed simulation to satellite, radiosonde, and radar data shows that the model reproduces the key features of the storm and its evolution. In particular also substantial hail precipitation at the surface is predicted. Here, we will present first results including the simulation set-up, the evaluation of the baseline simulation, and the variability of hail forecasts from the ensemble simulation.<br>In a later stage of the project we aim to assess the relative contribution of the introduced model variations to changes in the microphysical evolution of the storm and to the fore- cast uncertainty in larger-scale meteorological conditions.</p>

 The Climate Response to Emissions Reductions due to COVID-19

2021 ◽  
Author(s):  
Chris Jones ◽  
Keyword(s):  
Atmospheric Composition ◽  
Shortwave Radiation ◽  
Initial Condition ◽  
Emissions Reductions ◽  
Near Surface ◽  
Surface Climate ◽  
Climate Signals ◽  
Near Term ◽  
Regional Analyses ◽  
The Impact

<p>Many nations responded to the COVID-19 pandemic by restricting travel and other activities during 2020, resulting in temporarily reduced emissions of CO2, other greenhouse gases and ozone and aerosol precursors. We perform a coordinated Intercomparison, CovidMIP, of Earth System model simulations to assess the impact on climate of these emissions reductions. Eleven models performed multiple initial-condition ensembles to produce over 280 simulations spanning both initial condition and model structural uncertainty. We find model consensus on reduced aerosol amounts (particularly over East Asia) and associated increases in surface shortwave radiation levels. However, any impact on near-surface temperature or rainfall during 2020-2024 is extremely small and is not detectable in this initial analysis. Regional analyses on a finer scale, and closer attention to extremes (especially linked to changes in atmospheric composition and air quality) are required to test the impact of COVID-19-related emission reductions on near-term climate.</p><p>This first-look at results has focussed on surface climate, but future analysis will include attribution of drivers of climate signals; longer term implications of emissions reductions and options for economic recovery; quantifying changes in extremes; influence on atmospheric circulation and the carbon cycle.</p>

scholarly journals Characterization of the Petrophysical Properties of the Timahdit Oil Shale Layers in Morocco

Geosciences ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 337
Author(s):  
Hanane Sghiouri El Idrissi ◽  
Abderrahim Samaouali ◽  
Younes El Rhaffari ◽  
Salah El Alami ◽  
Yves Geraud
Keyword(s):  
Thermal Conductivity ◽  
Organic Matter ◽  
Thermal Diffusivity ◽  
Oil Shale ◽  
Velocity Ratio ◽  
Organic Matter Content ◽  
Matter Content ◽  
S Wave ◽  
Wave Velocities ◽  
The Impact

In this work, we study the variability of the lithological composition and organic matter content of samples were taken from the different layers M, X and Y of the Timahdit oil shale in Morocco, in order to experimentally analyze the impact of this variability on petrophysical measurements. The objective of this study is to predict the properties of the layers, including their thermal conductivity, thermal diffusivity, porosity and P and S wave velocities. The results of the study of the impact of the organic matter content of the samples on the petrophysical measurements show that, regardless of the organic matter content, thermal conductivity and diffusivity remain insensitive, while P and S wave velocities decrease linearly and porosity increases with increasing organic matter content. On the other hand, the study of the organic matter variability content is consistent with the velocity ratio, so can be used as an organic matter indicator of the layers. Conductivity and thermal diffusivity are almost invariant to the variability of the organic matter.

The Impact of Manufacturing Technology on the Thermal and Electrical Properties of Ceramic Powders Intended for Spraying Using the APS Method

2011 ◽  
Vol 465 ◽  
pp. 219-222 ◽  
Author(s):  
Grzegorz Moskal ◽  
Andrzej Grabowski
Keyword(s):  
Thermal Diffusivity ◽  
Spray Drying ◽  
Internal Structures ◽  
Spherical Structures ◽  
Thermal And Electrical Properties ◽  
Chemical And Phase Compositions ◽  
Surface Morphologies ◽  
The Impact ◽  
Spraying Method ◽  
Individual Particles

This article describes the microstructures, chemical and phase compositions, surface morphologies, and internal structures of three ZrO2 x 8Y2O3-type of powders obtained by different manufacturing methods. The first of the analyzed powders was a conventionally prepared form of the material obtained by the spraying method. The second powder was a spherically shaped form of the material obtained from the spray drying process. It displayed a distinctive surface morphology characterized by a rough structure with visible cavities. The particle sizes of these two powders were comparable. The third form of the powder was classified as “nano” and was obtained by a grinding and crushing method. The shapes of individual particles were generally polyhedral with smooth surfaces and no visible porosity. A study of the chemical composition of each form of the powder did not show significant differences, similar to the results obtained from the phase composition study. The results of thermal diffusivity and electrical impedance studies indicated that the electrical and thermal properties of the powders with spherical structures, i.e., sprayed and spray drying, were very similar. The thermal diffusivity and impedance properties of these two powders were greater than those of the ground powder with a finer grain size.

scholarly journals Thermal Diffusivity Measurement of Laser-Deposited AISI H13 Tool Steel and Impact on Cooling Performance of Hot Stamping Tools

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 154 ◽  
Author(s):  
Jon Iñaki Arrizubieta ◽  
Magdalena Cortina ◽  
Arantza Mendioroz ◽  
Agustín Salazar ◽  
Aitzol Lamikiz
Keyword(s):  
Thermal Diffusivity ◽  
Hot Stamping ◽  
Reference Value ◽  
Added Value ◽  
Additive Process ◽  
Effective Thermal Diffusivity ◽  
Thermal Diffusivity Measurement ◽  
Aisi H13 ◽  
The Impact ◽  
Aisi H13 Tool Steel

Additive manufacturing is a technology that enables the repair and coating of high-added-value parts. In applications such as hot stamping, the thermal behavior of the material is essential to ensure the proper operation of the manufactured part. Therefore, the effective thermal diffusivity of the material needs to be evaluated. In the present work, the thermal diffusivity of laser-deposited AISI H13 is measured experimentally using flash and lock-in thermography. Because of the fast cooling rate that characterizes the additive process and the associated grain refinement, the effective thermal diffusivity of the laser-deposited AISI H13 is approximately 15% lower than the reference value of the cast AISI H13. Despite the directional nature of the process, the laser-deposited material’s thermal diffusivity behavior is found to be isotropic. The paper also presents a case study that illustrates the impact of considering the effective thermal conductivity of the deposited material on the hot stamping process.

GENERALIZED SKLYANIN ALGEBRA AND INTEGRABLE LATTICE MODELS

1994 ◽  
Vol 09 (13) ◽  
pp. 2245-2281 ◽  
Author(s):  
YAS-HIRO QUANO
Keyword(s):  
Inverse Problem ◽  
Lattice Model ◽  
Lattice Models ◽  
Baxter Equation ◽  
Initial Condition ◽  
Infinite Dimensional ◽  
Integrable Lattice ◽  
Crossing Symmetry ◽  
Sklyanin Algebra ◽  
Integrable Lattice Models

We study three properties of the ℤn⊗ℤn-symmetric lattice model; i.e. the initial condition, the unitarity and the crossing symmetry. The scalar factors appearing in the unitarity and the crossing symmetry are explicitly obtained. The [Formula: see text]-Sklyanin algebra is introduced in the natural framework of the inverse problem for this model. We build both finite- and infinite-dimensional representations of the [Formula: see text]-Sklyanin algebra, and construct an [Formula: see text] generalization of the broken ℤN model. Furthermore, the Yang-Baxter equation for this new model is proved.

Thermophysical reservoir properties of the Hauptdolomit-facies underneath the Viennese basin across fault zones analogues – a reservoir study for the GeoTief EXPLORE project

2020 ◽  
Author(s):  
Doris Rupprecht ◽  
Sven Fuchs ◽  
Andrea Förster ◽  
Mariella Penz-Wolfmayr
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Fractured Rocks ◽  
Damage Zone ◽  
Fault Zones ◽  
Rock Properties ◽  
Zone Model ◽  
Geothermal Resources ◽  
Fault Rocks ◽  
The Impact

<p>The GeoTief EXPLORE project aims to explore the geothermal potential and quantify the geothermal resources of the Vienna Basin (Austria) and the underlying Northern Calcareous Alpine basement. The main target of geothermal interest is the massive and tectonically remolded Hauptdolomite facies that has been identified as potential geothermal reservoir in previous studies. Now, this formation is studied using outcrop analogues for the investigation of their petrophysical characterization and specific thermal properties (thermal conductivity and thermal diffusivity).</p><p> </p><p>Here, we report new measurements on a total of 60 samples from 6 outcrops in and around the area of Vienna applying different methods for the laboratory measurement of thermal and hydraulic rock properties. The petrophysical analysis considers the impact of deformation along and across fault zones, which introduces heterogeneity of storage properties and consequently in the thermophysical properties. Using the standard fault core and damage zone model, outcrop samples were grouped into unfractured and fractured protoliths, as well as in fault rocks, like breccias and cataclasites. Rock samples are then classified by their fracture density (m² fracture surface per m³ rock) and by their matrix content and differences in grain sizes, respectively.</p><p> </p><p>The measured thermal rock properties vary significantly between the selected rock groups. The total range [90 % of values] is between 3.2 and 5.0 W/(mK) for thermal conductivity and between 1.3 and 2.7 mm²/s for thermal diffusivity. The results generally met the expected trend for fractured rocks as conductivity and diffusivity decreases with increasing porosity under unsaturated and saturated conditions. The total porosities are less than 5%. The variability of thermal conductivity under saturated conditions shows complex trends depending on the different rock classifications where fault rocks and highly fractured rocks of the damage zone show lower increase in thermal conductivities.</p><p> </p><p>The new petrophysical characterization will be the base for further numerical investigations of the hydraulic and thermal regime as well as for the analysis of the geothermal resources of the Hauptdolomite.</p><p> </p><p> </p><p> </p><p> </p>

scholarly journals Probabilistic forecasting of plausible debris flows from Nevado de Colima (México) using data from the Atenquique debris flow, 1955

2018 ◽  
Author(s):  
Andrea Bevilacqua ◽  
Abani K. Patra ◽  
Marcus I. Bursik ◽  
E. Bruce Pitman ◽  
José Luis Macías ◽  
...  
Keyword(s):  
Inverse Problem ◽  
Debris Flow ◽  
Hazard Assessment ◽  
Hazard Analysis ◽  
Multiple Models ◽  
Probabilistic Forecasting ◽  
Flow Models ◽  
Using Data ◽  
Averaged Models ◽  
The Impact

Abstract. We detail a new prediction-oriented procedure aimed at volcanic hazard assessment based on geophysical mass flow models constrained with heterogeneous and poorly defined data. Our method relies on an itemized application of the empirical falsification principle over an arbitrarily wide envelope of possible input conditions. We thus provide a first step towards a objective and partially automated experimental design construction. In particular, instead of fully calibrating model inputs on past observations, we create and explore more general requirements of consistency, and then we separately use each piece of empirical data to remove those input values that are not compatible with it, hence defining partial solutions to the inverse problem. This has several advantages compared to a traditionally posed inverse problem: (i) the potentially non-empty inverse images of partial solutions of multiple possible forward models characterize the solutions to the inverse problem; (ii) the partial solutions can provide hazard estimates under weaker constraints, potentially including extreme cases that are important for hazard analysis; (iii) if multiple models are applicable, specific performance scores against each piece of empirical information can be calculated. We apply our procedure to the case study of the Atenquique volcaniclastic debris flow, which occurred on the flanks of Nevado de Colima volcano (México), 1955. We adopt and compare three depth averaged models currently implemented in the TITAN2D solver, available from vhub.org. The associated inverse problem is not well-posed if approached in a traditional way. We show that our procedure can extract valuable information for hazard assessment, allowing the exploration of the impact of synthetic flows similar to those that occurred in the past, but different in plausible ways. The implementation of multiple models is thus a crucial aspect of our approach, as they can allow the covering of other plausible flows. We also observe that model selection is inherently linked to the inversion problem.

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