179,629 research outputs found
A study of flame-vortex interactions in the presence of residual gases
No full textIn this work the effects of residual combustion products from a prior injection on flame extinction characteristics in a Diesel fuel pulse are investigated through a fundamental study. A numerical code with sixth-order accurate spatial discretization and multiple-step chemical kinetics is used to simulate flame-vortex interactions under Diesel conditions in the presence of residual combustion product mixtures. The results indicate that there is a balance between the heating effect of the high-temperature combustion products that enhance flame stability and the dilution effect of the reduced oxygen concentration, which promotes extinction. These counteracting aspects of the entrained combustion products can lead to an ideal dwell time between multiple injection events for optimum benefits in flame stability.Jonathan W. Anders, Rishikesh Venugopal, Vinicio Magi, and John Abraha
Spatial pattern of nerve differentiation in Hydra is due to a pattern of nerve commitment
No full textThe pattern of nerve differentiation along the body column of Hydra was investigated. Nerve precursors in late S phase were labeled with [3H]thymidine and their distribution compared with that of newly differentiated nerves. The two distributions were found to be the same. Based on independent evidence that nerve commitment occurs in mid-to late S phase (G. Venugopal and C. David, 1981, Develop. Biol.83, 361–365) it was concluded that the pattern of nerve differentiation along the body column of Hydra is due to differences in nerve commitment in different body regions. Furthermore, the level of nerve commitment in head and foot tissue is sufficiently high to deplete stem cells in these regions as is observed
Prashanth C. R KB Raja KR Venugopal
No full textThe signature verification system is always the most sought after biometric verification system. Being a behavioral biometric trait which can be imitated, the researcher faces a challenge in designing such a system to counter intrapersonal and interpersonal variations. This papers presents DWT based Off-line Signature Verification using Angular Features (DOSVAF). The signature is resized and Discrete Wavelet Transform (DWT) is applied to get four bands. The approximation band is considered and skeletonized. The exact signature area is cropped and resized so that the fair comparison is made among the signatures to produce better result. The angular features are extracted by dividing the signature image into number of blocks. The angular features of database and test signature are compared using distance metric. It is found that the values of FAR and FRR at optimal threshold are better compared to that of existin
TeraWatt North Atlantic spectral wave model input files (for MIKE 21)
No full textNORTH ATLANTIC MIKE 21 MODEL INPUT FILES
This submission includes the input files for the North Atlantic spectral wave model that is described in [1,2]. It formed part of the TeraWatt and EcoWatt2050 EPSRC projects (grant numbers EP/J010170/1 &
EP/K012851/1 respectively).
The input files require the MIKE 21 modelling suite to run, available commercially from https://www.mikepoweredbydhi.com/; they were created and validated using the 2014 edition. Input files are being stored instead of outputs as per RCUK guidelines due to the size of the output files.
For further information please contact Dr. Vengatesan Venugopal, School of Engineering, University of Edinburgh ([email protected]).
[1] V. Venugopal and R. Nemalidinne, ‘Wave resource assessment for Scottish waters using a large scale North Atlantic spectral wave model’, Renewable Energy, vol. 76, no. Supplement C, pp. 503–525, Apr. 2015.
[2] V. Venugopal, R. Nemalidinne, and A. Vögler, ‘Numerical modelling of wave energy resources and assessment of wave energy extraction by large scale wave farms’, Ocean & Coastal Management, Mar. 2017.See readme.txt
Extinction and Re-Ignition in Non-Premixed Flame-Vortex Interactions under Diesel Conditions
No full textIn this work, 2-D numerical investigations of extinction and re-ignition during interactions of counter-rotating vortex-pairs with a non-premixed flame are carried out under pressures and temperatures encountered in Diesel chambers. A direct-numerical simulation (DNS) code which employs sixth-order spatial accuracy and fourth-order time-integration is employed to solve the Navier-Stokes equations with chemical reactions. N-heptane is chosen as a representative fuel and irreversible single-step and two-step kinetic models are employed. Several representative values for the vortex circulation and length-scale are chosen from the analysis of the near-field of a Diesel jet. Results show that due to the vortex-induced strain, local extinction occurs along the symmetry axis. This extinction is predicted well by 1-D laminar flamelet libraries provided the time-history of the scalar dissipation rate is taken into account. The flame-edges resulting from local extinction interact leading to re-ignition as the initial vortex size approaches the initial flame thickness. This re-ignition phenomenon is 2-D, involves a partially-premixed flame structure and is not predicted by 1-D diffusion flamelet libraries. The results are summarized in terms of a regime diagram constructed from non-dimensional parameters such as the length-scale ratio and the Damkihler number
A Coupled LES-DNS Study of Physicochemical Processes in the Near Field of Transient Jets under Engine Conditions
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
TeraWatt North Atlantic spectral wave model input files (for MIKE 21)
No full textNORTH ATLANTIC MIKE 21 MODEL INPUT FILES This submission includes the input files for the North Atlantic spectral wave model that is described in [1,2]. It formed part of the TeraWatt and EcoWatt2050 EPSRC projects (grant numbers EP/J010170/1 & EP/K012851/1 respectively). The input files require the MIKE 21 modelling suite to run, available commercially from https://www.mikepoweredbydhi.com/; they were created and validated using the 2014 edition. Input files are being stored instead of outputs as per RCUK guidelines due to the size of the output files. For further information please contact Dr. Vengatesan Venugopal, School of Engineering, University of Edinburgh ([email protected]). [1] V. Venugopal and R. Nemalidinne, ‘Wave resource assessment for Scottish waters using a large scale North Atlantic spectral wave model’, Renewable Energy, vol. 76, no. Supplement C, pp. 503–525, Apr. 2015. [2] V. Venugopal, R. Nemalidinne, and A. Vögler, ‘Numerical modelling of wave energy resources and assessment of wave energy extraction by large scale wave farms’, Ocean & Coastal Management, Mar. 2017.Venugopal, Vengatesan. (2017). TeraWatt North Atlantic spectral wave model input files (for MIKE 21), 2010 [dataset]. School of Engineering, University of Edinburgh. http://dx.doi.org/10.7488/ds/2216
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
MIKE 21 West Orkney Monthly Hs Summary Outputs
No full textMIKE 21 WEST ORKNEY MONTHLY Hs SUMMARY OUTPUTS
This collection of netCDF format files contains monthly summary outputs of significant wave height (Hs) from the West of Orkney MIKE 21 spectral wave model described in [1]. For each month the mean Hs and the values of the 5,10,20...,90,95th percentiles are given for each cell in the model.
The model was designed to study the effects on wave height of both wave energy extraction and climate change.
Four scenarios are included: Present day (2010) with and without wave energy convertors, and future climate (~2050) with and without wave energy convertors. See [1] for more detail on present-day; a future publication will describe the future version.
This model was developed under the TeraWatt and EcoWatt2050 EPSRC projects (grant numbers EP/J010170/1 & EP/K012851/1 respectively). The data archived here are being used within the EcoWatt project for ongoing ecological studies.
For the input files for the model used to produce these outputs, please see submission "WEST ORKNEY MIKE 21 MODEL INPUT FILES" in this repository.
For further information please contact Dr. Vengatesan Venugopal, School of Engineering, University of Edinburgh ([email protected]).
[1] V. Venugopal, R. Nemalidinne, and A. Vögler, ‘Numerical modelling of wave energy resources and assessment of wave energy extraction by large scale wave farms’, Ocean & Coastal Management, Mar. 2017
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