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Agarwal, Pankaj

Scanning Sky Monitor On-Board AstroSat

Abstract Views :258 | PDF Views:90

Authors

M. C. Ramadevi ¹, S. Seetha ², Dipankar Bhattacharya ³, B. T. Ravishankar ¹, N. Sitaramamurthy ¹, G. Meena ¹, M. Ramakrishna Sharma ¹, Ravi Kulkarni ¹, V. Chandra Babu ¹, Kumar ¹, Brajpal Singh ¹, Anand Jain ¹, Reena Yadav ¹, S. Vaishali ¹, B. N. Ashoka ¹, Anil Agarwal ¹, K. Balaji ⁴, Manoj Kumar ⁵, Prashanth Kulshresta ⁵, Pankaj Agarwal ⁶, Mathew Sebastian ⁶

Affiliations
1 Space Astronomy Group, SSIF, ISITE Campus, Karthik Nagar, Outer Ring Road, ISRO Satellite Centre, Bengaluru 560 037, IN
2 Indian Space Research Organisation Headquarters, Department of Space, Antariksh Bhavan, New BEL Road, Bengaluru 560 231, IN
3 Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, IN
4 Spacecraft Mechanisms Group, ISAC, Old Airport Road, Vimanapura Post, Bengaluru 560 017, IN
5 Control and Digital Electronics Group, ISAC, Old Airport Road, Vimanapura Post, Bengaluru 560 017, IN
6 Vikram Sarabhai Space Center, Thiruvananthapuram 695 022, IN

Source

Current Science, Vol 113, No 04 (2017), Pagination: 599-601

Abstract

Scanning Sky Monitor (SSM) on-board AstroSat is a wide-field imager to monitor the X-ray sky in the energy band 2.5-10 keV. The primary science objective of SSM is to detect and locate transient X-ray sources in the sky. Once detected the information is to be provided to the astronomical community for follow-up observations to do a more detailed study of the source. Long-term monitoring of known X-ray transient sources is also one of the science objectives of SSM. The instrument constitutes three units of 1D positionsensitive propotional counters with coded masks on each, all three mounted on a platform capable of rotation to scan about 50% of the sky in one full rotation. The angular resolution of each unit in SSM is 12' x 2.5°. Sensitivity of SSM is ~30 milliCrab at 3 sigma in 10 min integration time. This article briefly discusses the instrument and a few early results since the launch of AstroSat.

Keywords

AstroSat, Crab, Scanning Sky Monitor, X-Ray Transient Sources.

Full Text

References

Agrawal, P. C., A broad spectral band Indian Astronomy satellite AstroSat. Adv. Space Res., 2006, 38, 29892994.

Singh, K. P. et al., AstroSat mission. Proc. SPIE, 2014, 91442T, 9144-100; doi:10.1117/12.2062667.

Levine, A. M. et al., First results from the All-Sky Monitor on the Rossi X-ray Timing Explorer. ApJ, 1996, 469, L33.

Seetha, S. et al., The Scanning Sky Monitor (SSM) on AstroSat. Adv. Space Res., 2006, 38, 2995–2998.

Matsuoka, M. et al., The MAXI mission on the ISS: science and instruments for monitoring All-sky X-ray images. PASJ, 2009, 61, 999.

Balaji, K., Narendra, S., Nagesh, G., Sridharamurthy, V. and Bhat, N. C., Development of mechanisms for AstroSat. In Proceedings of the 5th National Seminar and Exhibition on Aerospace and Related Mechanisms, ISRO Satellite Centre, Bengaluru, 18–19 November 2005, ARMS-05-MSA-02, pp. 67–73.

Ramadevi, M. C., Seetha, S., Babu, V. C., Ashoka, B. N. and Sreekumar, P., Optimization of gas proportional counters for Scanning Sky Monitor (SSM) onboard AstroSat. Adv. Space Res., 2006, 38, 3002–3004.

Ramadevi, M. C. et al., Scanning sky monitor (SSM) on-board AstroSat. Exp. Astron., 2017, doi:10.1007/s10686-017-9536-3.

Ramadevi, M. C. et al., Early in-orbit performance of Scanning Sky Monitor onboard AstroSat. J. Astrophys. Astr., 2016; doi:12.3456/s78910-011-012-3.

Ramadevi, M. C. et al., Detection of beta-class variability in black hole source GRS 1915+105 by AstroSat Scanning Sky Monitor. The Astronomer’s Telegram ATel #8185, 2015.

Shear Resistance Behaviour of Geogrid-Confined RC Elements Under Static and Cyclic Loading

Abstract Views :248 | PDF Views:68

Authors

R. Siva Chidambaram ¹, Pankaj Agarwal ²

Affiliations
1 CSIR-Central Building Research Institute, Roorkee 247 667, IN
2 Department of Earthquake Engineering, Indian Institute of Technology Roorkee, Roorkee 247 667, IN

Source

Current Science, Vol 117, No 2 (2019), Pagination: 260-271

Abstract

The present experimental work is concerned with the application of geogrid as partial transverse reinforcement in reinforced concrete beams and exterior beamcolumn joints. The composite advantages of steel fibre with minimum percentage and geogrid in resisting the shear force of beam and beam-column joint specimens with increased stirrup spacing under static and reverse cyclic loading are studied in detail. The loaddeflection curve, hysteretic loop, post-elastic strength and stiffness degradation, energy dissipation, failure pattern and damage tolerance capacity are the parameters used in this study to evaluate the performance of adopted new confinement technique. The improved shear carrying capacity with better inelastic response represents the advantages of the geogrid in RC structural elements. Also the enhanced energy dissipation and better damage tolerance of composite action provided by geogrid and steel fibre authenticate the use of synergetic effect in resisting the shear force in RC beams and beam-column joints.

Keywords

Cyclic Behaviour, Damping, Damage Tolerance, Geogrid Confinement, Hysteretic Behaviour, Moment Rotation, SFRC.

Full Text

References

Parra-Montesinos, G. J., Shear strength of beams with deformed steel fibres. Concr. Int., 2006, 28(11), 57.

Gençoğlu, M. and Eren, I., An experimental study on the effect of steel fiber reinforced concrete on the behavior of the exterior beam-column joints subjected to reversal cyclic loading. Turkish J. Eng. Env. Sci., 2002, 26(6), 493–502.

Susetyo, J., Gauvreau, P. and Vecchio, F. J., Effectiveness of steel fibres as crack controllers, assessment using shear panel tests. In Fracture Mechanics of Concrete and Concrete Structures-High Performance, Fiber Reinforced Concrete, Special Loadings and Structural Applications (eds Oh, B. H. et al.), Proc. FraMCoS-7, 2010, pp. 1478–1486.

Venkateshwaran, A. and Tan, K. H., Load‐carrying capacity of steel fibre reinforced concrete beams at large deflections. Struct. Conc., 2017; doi:10.1002/suco.201700129.

American Concrete Institute-ACI Committee, 1996. ACI 544.1 R96, state-of-the-art report on fibre reinforced concrete. ACI Committee, Detroit.

Tiberti, G., Germano, F., Mudadu, A. and Plizzari, G. A., An overview of the flexural post‐cracking behaviour of steel fibre reinforced concrete. Struct. Concr., 2018, 19(3), 695–718; doi:10.1002/suco.201700068.

Chidambaram, R. S. and Agarwal, P., Flexural and shear behaviour of geogrid confined RC beams with steel fibre reinforced concrete. Constr. Build. Mater., 2015, 78, 271–280.

Hwang, S. J., Lee, H. J., Liao, T. F., Wang, K. C. and Tsai, H. H., Role of hoops on shear strength of reinforced concrete beamcolumn joints. ACI Struct. J., 2005, 102(3), 445–453.

Lee, J. Y., Kim, J. Y. and Oh, G. J., Strength deterioration of reinforced concrete beam–column joints subjected to cyclic loading. Eng. Struct., 2009, 31(9), 2070–2085.

Costa, R., Providência, P. and Dias, A., Component‐based reinforced concrete beam–column joint model. Struct. Concr., 2017, 18(1), 164–176.

Alameddine, F. and Ehsani, M. R., High-strength RC connections subjected to inelastic cyclic loading. J. Struct. Eng., 1991, 117(3), 829–850.

Dadi, V. S. K. and Agarwal, P., Influence of reinforcement characteristics on non-linear performance evaluation of confined beam-column joints under cyclic loading. Adv. Civil Eng. Mater., 2013, 2(1), 201–217.

Murty, C. V. R., Rai, D. C., Bajpai, K. K. and Jain, S. K., Effectiveness of reinforcement details in exterior reinforced concrete beam-column joints for earthquake resistance. ACI Struct. J., 2003, 100(2), 149–156.

Dadi, V. V. S. S. K. and Agarwal, P., Cyclic performance evaluation of unconfined and confined beam-column joint specimens with different type of reinforcing characteristics as per ASCE/SEI 41–06. Aust. J. Struct. Eng., 2013, 14(3), 258–272.

Kotsovou, G. and Mouzakis, H., Seismic design of RC external beam-column joints. Bull. Earthq. Eng., 2002, 10(2), 645– 677.

Jiuru, T., Chaobin, H., Kaijian, Y. and Yongcheng, Y., Seismic behaviour and shear strength of framed joint using steel-fibre reinforced concrete. J. Struct. Eng., 1992, 118(2), 341–358.

Campione, G., La Mendola, L. and Papia, M., Shear strength of steel fibre reinforced concrete beams with stirrups. Struct. Eng. Mech., 2006, 24(1), 107–136.

Ganesan, N., Indira, P. V. and Abraham, R., Steel fibre reinforced high performance concrete beam-column joints subjected to cyclic loading. ISET J. Earthq. Technol., 2007, 44(3–4), 445–456.

Somma, G., Shear strength of fibre reinforced concrete beamcolumn joints under seismic loading, In Proceedings of 14th World Conference on Earthquake Engineering, Beijing, China, 12–17 October 2008.

Narayanan, R. and Darwish, I. Y. S., Use of steel fibres as shear reinforcement. ACI Struct. J., 1997, 84(3), 216–227.

Li, V. C., Ward, R. and Hmaza, A. M., Steel and synthetic fibres as shear reinforcement. ACI Mater. J., 1992, 89(5), 499– 508.

Dinh, H. H., Parra-Montesinos, G. J. and Wight, J. K., Shear behaviour of steel fibre-reinforced concrete beams without stirrup reinforcement. ACI Struct. J., 2010, 107(5), 597–606.

Daviau‐Desnoyers, D., Charron, J. P., Massicotte, B., Rossi, P. and Tailhan, J. L., Influence of reinforcement type on macrocrack propagation under sustained loading in steel fibre‐reinforced concrete. Struct. Concr., 2016, 17(5), 736–746.

Adebar, P., Mindess, S., St-Pierre, D. and Olund, B., Shear tests of fibre concrete beams without stirrups. ACI Struct. J., 1997, 94(1), 68–76.

Kwak, Y. K., Eberhard, M. O., Kim, W. S. and Kim, J., Shear strength of steel fibre-reinforced concrete beams without stirrups. ACI Struct. J., 2002, 99(4), 530–538.

Naaman, A. E., SIFCON – tailored properties for structural performance. In High Performance Fiber Reinforced Cement Composites, World Scientific, 2008, pp. 18–38.

Altun, F., Haktanir, T. and Ari, K., Effects of steel fibre addition on mechanical properties of concrete and RC beams. Construct. Build. Mater., 2007, 21(3), 654–661.

Boulekbache, B., Hamrat, M., Chemrouk, M. and Amziane, S., Flow ability of fibre-reinforced concrete and its effect on the mechanical properties of the material. Constr. Build. Mater., 2010, 24(9), 1664–1671.

Tang, X., Kim, S. and Chehab, G. R., Laboratory study of geogrid reinforcement in Portland cement concrete. In RILEM International Conference on Cracking Pavements, Chicago, Illinois, 16– 18 June 2008.

El Meski, F. and Chehab, G. R., Flexural behaviour of concrete beams reinforced with different types of geogrids. J. Mater. Civil Eng., 2013, 26(8).

Chidambaram, R. S. and Agarwal, P., The confining effect of geogrid on the mechanical properties of concrete specimens with steel fibre under compression and flexure. Constr. Build. Mater., 2013, 71, 628–637.

Sivakamasundari, S., Joshua Daniel, A. and Arun Kumar, Study on flexural behaviour of steel fiber RC beams confined with biaxial geo-grid. Proc. Engg., 2017, 173, 1431–1438.

Yalciner, H., Kumbasaroglu, A., Ertuc, I. and Turan, A. I., Confinement effect of geo-grid and conventional shear reinforcement bars subjected to corrosion. Structures, 2018, 13, 139–152.

Park, Y. J., Ang, A. H. and Wen, Y. K., Damage-limiting aseismic design of buildings. Earthq. Spectra, 1987, 3(1), 1–26.

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