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16 results on '"Frew, D.j."'

1. Pulse shaping techniques for testing elastic-plastic materials with a split Hopkinson pressure bar

Author

Frew, D.J., Forrestal, M.J., and Chen, W.

Subjects
Stress analysis (Engineering) -- Methods -- Mechanical properties, Elasticity -- Testing -- Mechanical properties -- Methods, Plastics -- Mechanical properties -- Testing -- Methods, Engineering and manufacturing industries, Testing, Mechanical properties, Methods
Abstract

ABSTRACT--We present pulse shaping techniques to obtain compressive stress-strain data for elastic-plastic materials with a split Hopkinson pressure bar. The conventional split Hopkinson pressure bar apparatus is modified by placing [...]

Published
2005

3. Dynamic compression testing of soft materials

Author

Chen, W., Lu, F., Frew, D.J., and Forrestal, M.J.

Subjects
Mechanics -- Research, Materials -- Dynamic testing, Strains and stresses -- Research, Science and technology
Abstract

Low-strength and low-impedance materials pose significant challenges in the design of experiments to determine dynamic stress-strain responses. When these materials are tested with a conventional split Hopkinson pressure bar, the specimen will not deform homogeneously and the tests are not valid. To obtain valid data, the shape of the incident pulse and the specimen thickness must be designed such that the specimens are in dynamic equilibrium and deform homogeneously at constant strain rates. In addition, a sensitive transmission bar is required to detect the weak transmitted pulses. Experimental results show that homogeneous deformations at nearly constant strain rates can be achieved in materials with very low impedances, such as a silicone rubber and a polyurethane foam, with the experimental modifications presented in this study. [DOI: 10.1115/1.1464871]

Published
2002

4. Penetration experiments with limestone targets and ogive-nose steel projectiles. (Brief Notes)

Author

Frew, D.J., Forrestal, M.J., and Hanchak, S.J.

Subjects
Technology -- Research, Limestone -- Research, Steel -- Research, Matter -- Properties, Projectiles -- Research, Science and technology
Abstract

We conducted three sets of depth-of-penetration experiments with limestone targets and 3.0 caliber-radius-head (CRH), ogive-nose steel rod projectiles. The ogive-nose rod projectiles with length-to-diameter ratios often were machined from 4340 [R.sub.c] 45 and Aer Met 100 [R.sub.c] 53 steel, round stock and had diameters and masses of 7.1 mm, 0.020 kg; 12.7 mm, 0.117 kg; and 25.4 mm, 0.931 kg. Powder guns or a two-stage, light-gas gun launched the projectiles at normal impacts to striking velocities between 0.4 and 1.9 km/s. In addition, we present an analytical penetration equation that described the target resistance by its density and a strength parameter determined from depth of penetration versus striking velocity data. [S0021-8936(01)00201-X]

Published
2000

7. The binary fraction of planetary nebula central stars: II. A larger sample and improved technique for the infrared excess search

Author

Douchin, D., De Marco, O., Frew, D.j., Jacoby, G.h., JASNIEWICZ, Gérard, Fitzgerald, M., Passy, J.c., Harmer, D., Hillwig, T., Moe, M., Macquarie University [Sydney], Laboratoire Univers et Particules de Montpellier (LUPM), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Giant Magellan Telescope Corporation, Department of Physics and Astronomy [Victoria], University of Victoria [Canada] (UVIC), Kitt Peak National Observatory (KPNO), National Optical Astronomy Observatory (NOAO), Department of Physics and Astronomy [Valparaiso], Valparaiso University, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
Stars: evolution, Stars: statistics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Binaries: general, Planetary nebulae: general, Surveys, Techniques: photometric
Abstract

International audience; There is no conclusive explanation of why ˜80 per cent of planetary nebulae (PNe) are non-spherical. In the Binary Hypothesis, a binary interaction is a preferred channel to form a non-spherical PN. A fundamental step to corroborate or disprove the Binary Hypothesis is to estimate the binary fraction of central stars of PNe (CSPNe) and compare it with a prediction based on the binary fraction of the progenitor, main-sequence population. In this paper, the second in a series, we search for spatially unresolved I- and J-band flux excess in an extended sample of 34 CSPN by a refined measurement technique with a better quantification of the uncertainties. The detection rate of I- (J-)band flux excess is 32 ± 16 per cent (50 ± 24 per cent). This result is very close to what was obtained in Paper I with a smaller sample. We account conservatively for unobserved cool companions down to brown dwarf luminosities, increasing these fractions to 40 ± 20 per cent (62 ± 30 per cent). This step is very sensitive to the adopted brightness limit of our survey. Accounting for visual companions increases the binary fraction to 46 ± 23 per cent (71 ± 34 per cent). These figures are lower than in Paper I. The error bars are better quantified, but still unacceptably large. Taken at face value, the current CSPN binary fraction is in line with the main-sequence progenitor population binary fraction. However, including white dwarfs companions could increase this fraction by as much as 13 (21) per cent points.

Published
2015

9. The VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+)

Author

Drew, J.E., Gonzalez-Solares, E., Greimel, R., Irwin, M.J., Yoldas, A. Küpcü, Lewis, J., Barentsen, G., Eislöffel, J., Farnhill, H.J., Martin, W.E., Walsh, J.R., Walton, N.A., Mohr-Smith, M., Raddi, R., Sale, S.E., Wright, N.J., Groot, P.J., Barlow, M.J., Corradi, R.L.M., Drake, J.J., Fabregat, J., Frew, D.J., Gänsicke, B.T., Knigge, C., Mampaso, A., Morris, R.A.H., Naylor, T., Parker, Q.A., Phillipps, S., Ruhland, C., Steeghs, D., Unruh, Y.C., Vink, J.S., Wesson, R., Zijlstra, A.A., Drew, J.E., Gonzalez-Solares, E., Greimel, R., Irwin, M.J., Yoldas, A. Küpcü, Lewis, J., Barentsen, G., Eislöffel, J., Farnhill, H.J., Martin, W.E., Walsh, J.R., Walton, N.A., Mohr-Smith, M., Raddi, R., Sale, S.E., Wright, N.J., Groot, P.J., Barlow, M.J., Corradi, R.L.M., Drake, J.J., Fabregat, J., Frew, D.J., Gänsicke, B.T., Knigge, C., Mampaso, A., Morris, R.A.H., Naylor, T., Parker, Q.A., Phillipps, S., Ruhland, C., Steeghs, D., Unruh, Y.C., Vink, J.S., Wesson, R., and Zijlstra, A.A.

Abstract

Contains fulltext : 127903.pdf (preprint version ) (Open Access)

Published
2014

10. A Planetary Nebula around Nova V458 Vulpeculae Undergoing Flash Ionization

Author

Wesson, R., Barlow, M.J., Corradi, R.L.M., Drew, J.E., Groot, P.J., Knigge, C., Steeghs, D., Gaensicke, B.T., Napiwotzki, R., Rodriguez-Gil, P., Zijlstra, A.A., Bode, M.F., Drake, J.J., Frew, D.J., Gonzalez-Solares, E.A., Greimel, R., Irwin, M.J., Morales-Rueda, L., Nelemans, G.A., Parker, Q.A., Sale, S.E., Sokoloski, J.L., Somero, A., Uthas, H., Walton, N.A., Warner, B., Watson, C.A., Wright, N.J., Wesson, R., Barlow, M.J., Corradi, R.L.M., Drew, J.E., Groot, P.J., Knigge, C., Steeghs, D., Gaensicke, B.T., Napiwotzki, R., Rodriguez-Gil, P., Zijlstra, A.A., Bode, M.F., Drake, J.J., Frew, D.J., Gonzalez-Solares, E.A., Greimel, R., Irwin, M.J., Morales-Rueda, L., Nelemans, G.A., Parker, Q.A., Sale, S.E., Sokoloski, J.L., Somero, A., Uthas, H., Walton, N.A., Warner, B., Watson, C.A., and Wright, N.J.

Abstract

Contains fulltext : 72738.pdf ( ) (Open Access) Contains fulltext : 72738.pdf (publisher's version ) (Closed access)

Published
2008

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