Integration of finite element modeling with solid modeling through a dynamic interface

Finite element modeling is dominated by geometric modeling type operations. Therefore, an effective interface to geometric modeling requires access to both the model and the modeling functionality used to create it. The use of a dynamic interface that addresses these needs through the use of boundary data structures and geometric operators is discussed

Integration of geometric modeling and advanced finite element preprocessing

The structure to a geometry based finite element preprocessing system is presented. The key features of the system are the use of geometric operators to support all geometric calculations required for analysis model generation, and the use of a hierarchic boundary based data structure for the major data sets within the system. The approach presented can support the finite element modeling procedures used today as well as the fully automated procedures under development

Approaches to the automatic generation and control of finite element meshes

The algorithmic approaches being taken to the development of finite element mesh generators capable of automatically discretizing general domains without the need for user intervention are discussed. It is demonstrated that because of the modeling demands placed on a automatic mesh generator, all the approaches taken to date produce unstructured meshes. Consideration is also given to both a priori and a posteriori mesh control devices for automatic mesh generators as well as their integration with geometric modeling and adaptive analysis procedures

Parallel unstructured grid generation for computational aerosciences

The objective of this research project is to develop efficient parallel automatic grid generation procedures for use in computational aerosciences. This effort is focused on a parallel version of the Finite Octree grid generator. Progress made during the first six months is reported

Velocity, oxygen uptake and metabolic cost of pull, kick and whole body swimming

Purpose: The contributions of the limbs to velocity and metabolic parameters in front-crawl swimming at different intensities have not been identified considering both stroke and kick rate. Consequently, velocity, oxygen uptake (VO2), and metabolic cost of swimming with the whole body (swim), the upper limbs only (pull), and lower limbs only (kick) were compared with stroke and kick rate controlled. Methods: Twenty elite swimmers completed six 200-m trials: 2 swim, 2 pull, and 2 kick. Swim trials were guided by underwater lights at paces equivalent to 65% +/- 3% and 78% +/- 3% of participants' 200-m-freestyle personal-best pace; paces were described as low and moderate, respectively. In the pull and kick trials, swimmers aimed to match the stroke and kick rates, respectively, recorded during the swim trials. (V)over dot O-2 was measured continuously, with velocity and metabolic cost calculated for each 200-m effort. Results: The velocity contribution of the upper limbs (mean +/- SD; low 63.9% +/- 6.2%, moderate 59.6% +/- 4.2%) was greater than that of the lower limbs to a large extent at both intensities (low ES = 4.40, moderate ES = 4.60). The (V) over dot O-2 used by the upper limbs differed between the intensities (low 55.5% +/- 6.9%, moderate 51.4% +/- 4.0%; ES = 0.74). The lower limbs were responsible for a greater percentage of the metabolic cost than the upper limbs at both intensities (low 56.1% +/- 9.5%, ES = 1.30; moderate 55.1% +/- 6.6%, ES = 1.55). Conclusions: Implementation of this testing protocol before and after a pull-or kick-training block will enable sport scientists to determine how the velocity contributions and/or metabolic cost of the upper-and lower-limb actions have responded to the training program

Radiative Forcing by Long-Lived Greenhouse Gases: Calculations with the AER Radiative Transfer Models

A primary component of the observed, recent climate change is the radiative forcing from increased concentrations of long-lived greenhouse gases (LLGHGs). Effective simulation of anthropogenic climate change by general circulation models (GCMs) is strongly dependent on the accurate representation of radiative processes associated with water vapor, ozone and LLGHGs. In the context of the increasing application of the Atmospheric and Environmental Research, Inc. (AER) radiation models within the GCM community, their capability to calculate longwave and shortwave radiative forcing for clear sky scenarios previously examined by the radiative transfer model intercomparison project (RTMIP) is presented. Forcing calculations with the AER line-by-line (LBL) models are very consistent with the RTMIP line-by-line results in the longwave and shortwave. The AER broadband models, in all but one case, calculate longwave forcings within a range of -0.20 to 0.23 W m{sup -2} of LBL calculations and shortwave forcings within a range of -0.16 to 0.38 W m{sup -2} of LBL results. These models also perform well at the surface, which RTMIP identified as a level at which GCM radiation models have particular difficulty reproducing LBL fluxes. Heating profile perturbations calculated by the broadband models generally reproduce high-resolution calculations within a few hundredths K d{sup -1} in the troposphere and within 0.15 K d{sup -1} in the peak stratospheric heating near 1 hPa. In most cases, the AER broadband models provide radiative forcing results that are in closer agreement with high 20 resolution calculations than the GCM radiation codes examined by RTMIP, which supports the application of the AER models to climate change research

Ozone-CO Correlations Determined by the TES Satellite Instrument in Continental Outflow Regions

Collocated measurements of tropospheric ozone (O3) and carbon monoxide (CO) from the Tropospheric Emission Spectrometer (TES) aboard the EOS Aura satellite provide information on O3-CO correlations to test our understanding of global anthropogenic influence on O3. We examine the global distribution of TES O3-CO correlations in the middle troposphere (618 hPa) for July 2005 and compare to correlations generated with the GEOS-Chem chemical transport model and with ICARTT aircraft observations over the eastern United States (July 2004). The TES data show significant O3-CO correlations downwind of polluted continents, with dO3/dCO enhancement ratios in the range 0.4–1.0 mol mol−1 and consistent with ICARTT data. The GEOS-Chem model reproduces the O3-CO enhancement ratios observed in continental outflow, but model correlations are stronger and more extensive. We show that the discrepancy can be explained by spectral measurement errors in the TES data. These errors will decrease in future data releases, which should enable TES to provide better information on O3-CO correlations.Earth and Planetary SciencesEngineering and Applied Science

Inverse modeling of NH3 sources using CrIS remote sensing measurements

Spatiotemporal uncertainty in emissions in the US hinders prediction of environmental effects of atmospheric . We conducted 4D-Var inversions using CrIS remote-sensing observations and GEOS-Chem to estimate monthly emissions over the contiguous US at the 0.25&deg;&times; 0.3125&deg; resolution in 2014, finding they are 33% higher than the prior emissions which likely underestimated most agricultural emissions, especially intense springtime fertilizer and livestock sources over the Central US. However, decreases were found in the Central Valley, southern Minnesota, northern Iowa and southeastern North Carolina during warm months. These updates increased the correlation coefficient between modeled monthly mean and surface observations from 0.53 to 0.84, and reduced the normalized mean bias of annual mean simulated and wet by a factor of 1.3 to 12.7. Our satellite-based inversion approach thus holds promise for improving estimates of and reactive nitrogen deposition throughout the world where measurements are scarce.</p