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Your search keyword '"Shajii, A."' showing total 19 results
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19 results on '"Shajii, A."'

2. Modelling of quench in CICC with a central channel in the conduit

Author

J. McCarrick, E.A. Chaniotakis, A. Shajii, and J.P. Freidberg

Subjects
Engineering, Electrical conduit, Thermonuclear fusion, Steady state, business.industry, Bundle, Heat transfer, Flow (psychology), Mechanical engineering, Hydraulic diameter, Mechanics, business, Communication channel
Abstract

This paper presents a theoretical model describing quench propagation in cable in conduit conductors (CICC) with an additional central flow channel. The central channel is used to enhance the flow capabilities in the conduit during steady state operation as well as during quench events. Such a system is the proposed design for certain conductors in the International Thermonuclear Experimental Reactor (ITER). Here, the additional channel is formed by a metal spring located at the center of the conduit. We describe the separate thermal evolution in both the cable bundle and the central channel; in particular, the mass, momentum and heat transfer due to flow between the cable bundle and the central channel are included in the model. Several simplifications are introduced which greatly reduce the complexity of the model without sacrificing accuracy. The resulting reduced model is solved both numerically and approximately analytically for ITER parameters.

Published
2002
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3. Analytic and numerical theory of quench in CICC

Author

J.P. Freidberg and A. Shajii

Subjects
Set (abstract data type), Engineering, business.industry, Numerical analysis, Heat transfer, CPU time, Mechanical engineering, Experimental data, Superconducting magnet, Central processing unit, Mechanics, business, Stability (probability)
Abstract

A new compact theoretical model is presented that describes the phenomena of quench propagation in Cable In Conduit superconducting magnets. The model circumvents many of the difficulties associated with obtaining numerical solution of more general existing models. Specifically, a factor of 30-50 is gained in the CPU time required to study typical quench events. The corresponding numerical implementation of the new model is described and the numerical results are shown to agree very well with those of the more general models, as well as with experimental data. By considering a set of simplifying assumptions the new quench model has also been solved analytically. The analytic solution is presented and is shown to be in very good agreement with the numerical results.

Published
2002
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4. A liquid shear-stress sensor fabricated using wafer bonding technology

Author

K.-Y. Ng, J. Shajii, and M.A. Schmidt

Subjects
Fabrication, Materials science, Silicon, Wafer bonding, business.industry, chemistry.chemical_element, Piezoresistive effect, Shear (sheet metal), chemistry, Electronic engineering, Shear stress, Shear strength, Optoelectronics, business, Layer (electronics)
Abstract

The authors report on the fabrication and testing of a microfabricated silicon floating-element (120 mu m*140 mu m) shear-stress sensor designed to detect high shear stresses (1-100 KPa) in fluid environments. Wafer bonding technology is used to produce a thin (5 mu m) dielectrically isolated silicon layer (allowing piezoresistive transduction in a half-bridge readout scheme) which is further processed to develop the floating-element sensor. The authors describe the details of the sensor fabrication, modeling of the sensor response, and the results of testing. There is good agreement between the modeled response of the sensor and the experimental data, and the sensor has also maintained its structural integrity under severe conditions. >

Published
2002
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5. Three dimensional quench and stability in CICC

Author

J.P. Freidberg, A. Shajii, and M.A. Ferri

Subjects
Superconductivity, Quenching, Materials science, Mathematical model, Thermal, Electronic engineering, Mechanics, Fusion power, Current density, Stability (probability), Electrical conductor
Abstract

A coupled thermal and electromagnetic model is formulated and solved to study the effects of radially non-uniform heat pulses and current densities in superconducting cable-in-conduit conductors. The results indicate that quench and stability behavior in cases with non-uniform radial conditions are more complicated and appreciably different than cases where uniform conditions are assumed over the cross-section of the cable. Specific cases are presented for an ITER-like CICC and energy margin calculations are compared with corresponding zero-dimensional estimates.

Published
2002
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6. TPX superconducting tokamak magnet system 1995 design and status overview

Author

M. Xu, D. Hartman, Makoto Takayasu, G. Markham, B. Wilmer, X. Huang, D. Stutski, D. Johanson, D. Potter, R. Ryan, Timothy A. Antaya, R. Parman, S. Pourrahimi, H. Calvin, I. Clarkson, R. Batchelder, G. J. Naumovich, C.R. Wendland, J. Luxom, R. Whitfield, D. Lang, R.L. Myatt, J. Lowry, M. Krefta, N. Martovetsky, J. Schulteiss, W. Young, W. Hannan, R.D. Pillsbury, M. Lajeunesse, Phillip Michael, D. Alger, S. Smith, T. Kupisewski, J. Zbasnik, G. Deis, P. Rackov, H. Bell, J. Hordabay, W. Bensiek, D. Johnson, C. Cesar, Y. Lvovsky, P. Walstrom, J. VandeBogart, R. Hillenbrand, G. Lehman, R. deKoven, C. Weber, B. Felker, S. M. Hibbs, C. Rey, R.H. Bulmer, J. Parker, S. Shen, D. Hoffman, R. Kunz, W. Urban, T. Brandesberg, P. Conde, M. Chaplin, E. Southwick, L. Pedrotti, A. Burger, G. Swartzback, W. Tong, J. Leuer, A. Corpuz, R. Hale, B. Holt, S. Jeong, S. Singh, R. Carpenter, K. Grut, J. Meissner, J. Citrolo, O. Christianson, R. Smith, P. Sanger, J.H. Schultz, Alexey Radovinsky, P. McAuliffe, E. Cassidy, E. Hook, N. Albritton, M. Jackson, J. Maloney, P. Wang, A. Shajii, J. Roach, C. Gibson, G. Korbel, and C. Moleni

Subjects
Superconducting tokamak, Materials science, Magnet, Mechanical engineering, Bending, Superconducting magnet, Fusion power, Superconducting Coils, Conductor, Coolant
Abstract

The TPX magnet preliminary design effort is summarized. Key results and accomplishments during preliminary design and supporting R&D are discussed, including conductor development, quench detection, TF and PF magnet design, conductor bending and forming, reaction heat treating, helium stubs, and winding pack insulation.

Published
2002
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14. TPX superconducting tokamak magnet system 1995 design and status overview

Author

Deis, G., primary, Bulmer, R., additional, Carpenter, R., additional, Cassidy, E., additional, Chaplin, M., additional, Felker, B., additional, Hibbs, S., additional, Jackson, M., additional, Korbel, G., additional, Lang, D., additional, Martovetsky, N., additional, Parker, J., additional, Pedrotti, L., additional, Shen, S., additional, Southwick, E., additional, Wendland, C., additional, Zbasnik, J., additional, Hale, R., additional, Jeong, S., additional, Michael, P., additional, Pillsbury, R., additional, Pourrahimi, S., additional, Radovinsky, A., additional, Schultz, J., additional, Shajii, A., additional, Smith, S., additional, Takayasu, M., additional, Wang, P., additional, Citrolo, J., additional, Myatt, R.L., additional, Albritton, N., additional, Alger, D., additional, Antaya, T., additional, Batchelder, R., additional, Bell, H., additional, Bensiek, W., additional, Brandesberg, T., additional, Conde, P., additional, deKoven, R., additional, Grut, K., additional, Johanson, D., additional, Hoffman, D., additional, Holt, B., additional, Hook, E., additional, Huang, X., additional, Kunz, R., additional, Lehman, G., additional, Lvovsky, Y., additional, Maloney, J., additional, Markham, G., additional, Meissner, J., additional, Rackov, P., additional, Rey, C., additional, Ryan, R., additional, Smith, R., additional, Stutski, D., additional, Tong, W., additional, VandeBogart, J., additional, Weber, C., additional, Whitfield, R., additional, Wilmer, B., additional, Xu, M., additional, Young, W., additional, Gibson, C., additional, Leuer, J., additional, Luxom, J., additional, Calvin, H., additional, Cesar, C., additional, Corpuz, A., additional, Lajeunesse, M., additional, McAuliffe, P., additional, Moleni, C., additional, Parman, R., additional, Potter, D., additional, Christianson, O., additional, Hannan, W., additional, Hillenbrand, R., additional, Hordabay, J., additional, Johnson, D., additional, Krefta, M., additional, Kupisewski, T., additional, Lowry, J., additional, Roach, J., additional, Sanger, P., additional, Singh, S., additional, Swartzback, G., additional, Urban, W., additional, Burger, A., additional, Clarkson, I., additional, Schulteiss, J., additional, Walstrom, P., additional, Hartman, D., additional, and Naumovich, G., additional

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