Papers by Siegfried Hecker
Foreign Affairs, Dec 9, 2010
Foreign Affairs, Dec 4, 2017
Physics Today, Feb 1, 2012
Stanford University Press eBooks, Nov 24, 2022
New Perspectives Quarterly, Oct 1, 2017
Actions of the Government of the Democratic People's Republic of Korea have precipitated ... more Actions of the Government of the Democratic People's Republic of Korea have precipitated two nuclear crises in the past 10 years. The 1994 crisis was resolved through the 'Agreed Framework.' North Korea agreed to 'freeze' and eventually dismantle its nuclear program (with U.S. help to store spent fuel safely and under IAEA inspection). In return, the United States agreed (with
Foreign Affairs, Dec 9, 2010
Mechanics of Materials, Apr 1, 1983
Abstract 2024 aluminum tubes, heat treated to a T6 and T8 temper, were proportionally loaded to f... more Abstract 2024 aluminum tubes, heat treated to a T6 and T8 temper, were proportionally loaded to failure with combinations of tension and internal pressure. We measured diffuse instability and fracture strains and compared these to the ductile fracture model of Ghosh (1976). Agreement was quite good. Fracture strains measured in axial tension and pure hoop tension were equivalent even though anisotropies were observed in the plastic deformation of the tubes.
Bulletin of The Atomic Scientists, Jan 21, 2014
Bulletin of The Atomic Scientists, Dec 20, 2010
Bulletin of The Atomic Scientists, Apr 11, 2017
NTI, Russian Academy of Sciences, Sep 10, 2009
Bulletin of the Atomic Scientists, 2016
ABSTRACT Stanford expert Siegfried Hecker proposes a series of nuclear weapons and energy questio... more ABSTRACT Stanford expert Siegfried Hecker proposes a series of nuclear weapons and energy questions that journalists and citizens should consider asking the 2016 presidential candidates.
Transactions of the American Nuclear Society, 1998
The first atomic bomb detonated at the Trinity Site in New Mexico on July 16, 1945, used plutoniu... more The first atomic bomb detonated at the Trinity Site in New Mexico on July 16, 1945, used plutonium, a man-made element discovered < 5 yr earlier. The story of how Manhattan Project scientists and engineers tackled the mysteries of this element and fabricated it into the first atomic bomb is one of the most fascinating in the history of metallurgy and materials. The authors are currently trying to generate renewed interest in plutonium metallurgy because of the challenge posed by President Clinton, i.e., to keep the nuclear stockpile of weapons safe and reliable without nuclear testing. The stockpile stewardship challenge requires either a lifetime extension of the plutonium components or a remanufacture--neither of which can be verified by testing. In turn, this requires that one achieve a better fundamental understanding of plutonium. Of special interest is the effect of self-irradiation on the properties and on the long-term stability of plutonium and its alloys. Additional cha...
Proceedings, annual meeting, Electron Microscopy Society of America, 1981
As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial... more As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear int...
Physica B+C, 1985
A major purpose CMthe Technk cal Information Center is to provide the broadest dissemination poss... more A major purpose CMthe Technk cal Information Center is to provide the broadest dissemination possible of information contained in DOE's Research and Development Reports to business, industry, the academic community, and federal, state and local governments. Although a small portion of this report is not reproducible, it is being made available to expedite the availability of information on the research discussed herein. ' 4'. . >' a' ..' %A-UR 84-3001 f/)7d cow-z+zY7f02-"5 M~Nstlona!Labwatwv~opwsM by h Un~of Callfornltfor Uw UnltW SUI.S Dopwmom of Enwy undw oonfracfW.74M.EN04S.
Four large (M[approximately]7+) earthquakes occurred in a nearly continuous, N-S belt in west-cen... more Four large (M[approximately]7+) earthquakes occurred in a nearly continuous, N-S belt in west-central Nevada between 1915 and 1954. The number of large earthquakes and the striking pattern of surface ruptures suggest that these earthquakes represent a burst of faulting that has implications for the nature of fault behavior in the Great Basin. The authors conducted geomorphic studies to estimate ages of Holocene-latest Pleistocene paleoseismic events across a broad portion of central Nevada ([approximately]42,000 km[sup 2]) to assess longer-term (10[sup 4]-yr) temporal and spatial patterns of faulting. Diffusion-based fault-scarp modeling, calibrated using pluvial shoreline scarps from this region, provided age estimates for paleoseismic events with estimated uncertainties of [+-]30%. Age estimates for faulted and unfaulted alluvial surfaces derived from soil-profile development, tephra, and dated organic material supplemented scarp age estimates. The age estimates for Holocene-latest Pleistocene paleoseismic events in central Nevada provide a chronology that is sufficient to outline the general rates and patterns of faulting. Recurrence intervals of 10,000+ years characterize most faults in this region; a few of the most active fault zones have recurrence intervals as short as several thousand years. Faulting during this century clearly represents a temporal cluster of activity, because the historical rate of large-earthquakemore » occurrence is about 10 times the longer-term average and central Nevada probably experienced only one large earthquake in the previous 2,000 years. Temporal and spatial clusters of paleoseismic activity apparently have occurred over intervals of several thousand years in portions of central Nevada. Mean age estimates for paleoseismic events suggest the possibility of short-term (<500-yr) temporal clusters of faulting across this region during the middle and late Holocene.« less
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Papers by Siegfried Hecker