Detection of Gravitational Redshift on the Solar Disk by Using Iodine-Cell Technique

With an aim to examine whether the predicted solar gravitational redshift can be observationally confirmed under the influence of the convective Doppler shift due to granular motions, we attempted measuring the absolute spectral line-shifts on a large number of points over the solar disk based on an extensive set of 5188-5212A region spectra taken through an iodine-cell with the Solar Domeless Telescope at Hida Observatory. The resulting heliocentric line shifts at the meridian line (where no rotational shift exists), which were derived by finding the best-fit parameterized model spectrum with the observed spectrum and corrected for the earth's motion, turned out to be weakly position-dependent as ~ +400 m/s near the disk center and increasing toward the limb up to ~ +600 m/s (both with a standard deviation of sigma ~ 100 m/s). Interestingly, this trend tends to disappear when the convectiveshift due to granular motions (~-300 m/s at the disk center and increasing toward the limb; simulated based on the two-component model along with the empirical center-to-limb variation) is subtracted, finally resulting in the averaged shift of 698 m/s (sigma = 113 m/s). Considering the ambiguities involved in the absolute wavelength calibration or in the correction due to convective Doppler shifts (at least several tens m/s, or more likely up to <~100 m/s), we may regard that this value is well consistent with the expected gravitational redshift of 633 m/s.Comment: 28 pages, 12 figures, electronic materials as ancillary data (table3, table 4, ReadMe); accepted for publication in Solar Physic

Generation of Long-Lived Isomeric States via Bremsstrahlung Irradiation

A method to generate long-lived isomeric states effectively for Mossbauer applications is reported. We demonstrate that this method is better and easier to provide highly sensitive Mossbauer effect of long-lived isomers (>1ms) such as 103Rh. Excitation of (gamma,gamma) process by synchrotron radiation is painful due mainly to their limited linewidth. Instead,(gamma,gamma') process of bremsstrahlung excitation is applied to create these long-lived isomers. Isomers of 45Sc, 107Ag, 109Ag, and 103Rh have been generated from this method. Among them, 103Rh is the only one that we have obtained the gravitational effect at room temperature.Comment: ICAME 05 conference repor

A grid-enabled problem solving environment (PSE) for design optimisation within matlab

The process of design search and optimisation using Computational Fluid Dynamics (CFD) is computationally and data intensive, a problem well-suited to Grid computing. The Geodise toolkit is a suite of Grid-enabled design optimisation and search tools within the Matlab environment. The use of these tools by the engineer is facilitated by intelligent design advisers targeted initially at CFD. The role of remote computation and data access in constructing a Grid-enabled Problem Solving Environment is discussed. The use of the Geodise toolkit for design optimisation from within the Matlab environment is considered with an exemplar problem

Tuning GENIE earth system model components using a Grid enabled data management system

We present the Grid enabled data management system that has been deployed for the GENIE project and demonstrate its use in tuning studies of an Earth system model. A Matlab client to the system provides a common environment for the project Virtual Organization to share scripts, binaries and output data. By using tools available in the Geodise toolkits we have scripted the execution of tuning studies which exploit multiple heterogeneous computational resources and use the database repository to steer computation using multi-dimensional optimisation methods

Matlab functions provide client functionality to the Grid

Several toolboxes have been developed by the Geodise project to enable engineers to perform Grid-enabled design search and optimisation from the Matlab technical computing environment. The toolboxes provide a suite of Matlab functions that facilitate the composition of scripts to automate the evaluation of engineering designs by design search and optimisation tools. The generic functionality provided by these toolboxes includes access to compute resources, data management, file transfer, and certificate management tools. The functions provide a simple interface that is intuitive to users familiar with the Matlab environment. In addition we provide higher-level composite functions that build upon the core functions to perform problem specific tasks. By integrating Grid client functionality into Problem Solving Environments used day-to-day by engineers we are lowering the barriers to entry for professionals wishing to exploit Grid technologie

Implementation and utilisation of a Grid-enabled problem solving environment in Matlab

In many areas of design search and optimisation one needs to utilise computational fluid dynamics (CFD) methods in order to obtain a numerical solution of the flow field in and/or around a proposed design. From this solution measures of quality for the design may be calculated, which are then used by the optimisation methods. In large models the processing time for the CFD computations can very well be many orders of magnitude larger than for the optimisation methods themselves; and the overall optimisation process usually demands a combination of computational and database resources; therefore this class of problems is well suited to Grid computing. The Geodise toolkit is a suite of tools for Grid-enabled parametric geometry generation, meshing, CFD analysis, design optimisation and search, databasing, Grid computing, and notification within the Matlab environment. These Grid services are presented to the design engineer as Matlab functions that conform to the usual syntax of Matlab. The use of the Geodise toolkit in Matlab introduces a flexible and Grid-enabled problem solving environment (PSE) for design search and optimisation. This PSE is illustrated here with two exemplar problems

GENIE: Exploiting Grid enabled computing and data handling resources for integrated Earth system modelling

The GENIE project is developing a grid based framework for the composition, execution and management of new Earth System Models, and the data they produce. Our principle aims are to• flexibly couple together state-of-the-art components to form unified Earth System Models (ESMs),• study and tune the resulting ESMs over multi-millennial timescales.We have achieved this by developing a framework and technologies which allow us to exploit:• grid-enabled computational resources, and• grid-enabled data management to allow post-processing, analysis and sharing of the distributed data produced by model runs.Our framework is based around the widely used Matlab problem solving environment and is also being extended to provide the same functionality for Python. It is built upon software developed by the UK Geodise project (www.geodise.org). A Matlab client provides a common environment for the project Virtual Organisation and allows the scripting of model execution through an interface to the computational Grid (Globus and Condor resources are supported). An augmented version of the Geodise Database Toolbox provides access to a grid-enabled repository for scripts, binaries and output data from the GENIE framework. In addition, rich metadata associated with these files is stored in a grid-enabled database, which can then be searched to locate files in the repository. We provide both GUI and programmatic access from the scripting environment to archive and retrieve files from the file repository and also to query the metadata store. An interface is also provided to a sophisticated Design Search and Optimisation package OPTIONS which has been exploited in some of our tuning studies.We will illustrate the use of our grid-enabled environment with a number of exemplars representative of the range of scientific challenges that we have been addressing. These include (1) ensemble studies of the behaviour of the ocean’s thermohaline circulation, (2) parameter tuning of coupled atmosphere, ocean and sea-ice models, and (3) multi-millennial timescale simulations. Our studies have used a wide range of local and national grid-enabled computational and data handling resources and have demonstrated how the grid can be exploited for integrated Earth system modelling