A time to find solutions

Carroll Wilson's article, Nuclear Energy: What Went Wrong (Bulletin. June 1979), is both interesting and perceptive. He points out quite correctly that at least two of the most criticized areas at the back end of the fuel cycle--reprocessing and nuclear wastes--required much more attention than was given. Also he Points out that for nuclear power the whole cycle must work. His comments on control rooms are well taken in addition to his comparison to the vastly more complicated Boeing 747. The quality and training of operators have now been singled out for special criticism in the recent Kemeny Report on the Three Mile Island accident

The Interaction of Configurations: sd−p^2

It does not seem possible to account for the presence of singlets below their triplets in two electron spectra simply from the ordinary exchange integrals. The exchange integrals seem to be essentially positive. It is shown that the matrix component of electrostatic energy connecting the 3s3d^1D with 3p^2^1D in Mg I is sufficiently large to account for the occurrence of 3s3d^1D below 3s3d^3D as observed experimentally. Analytic radial wave functions of the type developed by Slater are used in the calculation of the nondiagonal elements

Photoproduction of mesons and hyperons

The availability in recent years of increasingly energetic photon beams from particle accelerators has led to significant advances in the study of photon-nucleon interactions and the photoproduction of mesons and hyperons. This work also holds the promise of future contributions to better understanding of the nature of the strong interactions

Note on the Magnetic Moment of the Nitrogen Nucleus

Three lines of the group 2s2p^4^4P−2s^22p^24p^4D of N I have been examined for hyperfine structure. They were found to be single when examined with a Fabry-Perot interferometer, using a variety of plate separations. The line widths of two of the lines were measured. The absence of hyperfine structure is attributed to the small magnetic moment (μ) of the nitrogen nucleus. It is shown that, by using the results of Goudsmit, the measured line widths lead to an unusually low magnetic moment for the nitrogen nucleus, μ≦0.2(eh)/(4πMc). Under certain assumptions about the structure of the nitrogen nucleus, this low value of the magnetic moment leads to the conclusion that the neutron has a magnetic moment in the opposite direction from its mechanical moment and about one proton magneton in magnitude

Robert Oppenheimer (1904-1967)

ROBERT OPPENHEIMER died in Princeton, New Jersey on February 18, 1967, at the age of sixty-two. He was the leading American theoretical physicist of his generation, the founder of the most important school of theoretical physics, and one of the leading intellectuals of our day

On the reduction of nuclear weapons

The United States, in 1946, proposed that an international authority be formed to control the dangerous parts of atomic energy. The proposal met with very little success, except to lead to the conclusion that there was no apparent reason why it was not technically feasible. Discussions on nuclear weapons testing, initiated in 1958, reached some agreement on test restrictions in Subsequent years

The Hydrogen Bomb

Can it be made? Will it add to our national security? How effective will it be as a military weapon? How much more effective than the atomic bomb? Will the Russians be able to make it? Here are the answers to some of the questions most people ask about the H-bomb

Some Comments on Our Energy Problems

According to recent polls, the past severe winter seems finally to have convinced a majority of Americans that there really are serious energy problems. They also seem to be convinced that something must be done and may even be prepared to take some conservation measures that do not come naturally. In retrospect, while the Arab oil embargo prepared the way for this change in public opinion, too many believed that this was just a temporary crisis, soon to pass completely. As a good many people have said for several years, the quickest and most effective action is conservation. Whether the American public or the Congress will be enthusiastic about the effects of vigorous conservation remains to be seen

Modélisation physique de l'interaction entre obstacles et avalanches de neige poudreuse

International audienceIn order to better understand the interaction between powder snow avalanches and defence structures, we carried out physical experiments on small-scale models. The powder snow avalanche was simulated by a heavy salt solution in a water tank. Quasi two-dimensional and three-dimensional experiments were carried out with different catching dam heights. For the reference avalanche, the velocity just behind the nose in the head was greater than the front velocity. For the 2-D configuration, the ratio Umax/Ufront was as high as 1.6, but it depends on the height. For the 3-D configuration, this ratio differed slightly and was even greater (up to 1.8). The vertical velocity rose to 106% of the front velocity for the 3-D simulation and 74% for the 2-D simulation. The reduction in front velocity due to the presence of dams was an increasing function of the dam height. But this reduction depended on topography: dams were more effective on an open slope avalanche (3-D configuration). The ratio Umax/Ufront was an increasing function of the dam's height and reached a value of 1.9. The obstacle led to a reduction in vertical velocity downstream of the vortex zone