For Slow Neutrons, Slow Pay: Enrico Fermi’s Patent and the US Atomic Energy Program, 1938-1953

This essay focuses on the history of one of the “atomic patents.” The patent, which described a process to slow down neutrons in nuclear reactions, was the result of experimental research conducted in the 1930s by Enrico Fermi and his group at the Institute of Physics, University of Rome. The value of the patented process became clear during World War II, as it was involved in most of the military and industrial applications of atomic energy. This ignited a controversy between Fermi and U.S. government representatives over royalties to be paid for use of the process during and after the war. The controversy sheds new light on the role that the management of patents played in the context of the Manhattan Project and in the postwar U.S. nuclear program, encompassing issues of power and economic influence in the relationship between scientists, the military, and public administrators

Big Data Assurance Evaluation: An SLA-Based Approach.

The Big Data community has started noticing that there is the need to complete Big Data platforms with assurance techniques proving the correct behavior of Big Data analytics and management. In this paper, we propose a Big Data assurance solution based on Service-Level Agreements (SLAs), focusing on a platform providing Model-based Big Data Analytics-as-a-Service (MBDAaaS)

On the origin of the deflection of light

Action at distance in Newtonian physics is replaced by finite propagation speeds in classical post--Newtonian physics. As a result, the differential equations of motion in Newtonian physics are replaced by functional differential equations, where the delay associated with the finite propagation speed is taken into account. Newtonian equations of motion, with post--Newtonian corrections, are often used to approximate the functional differential equations. In ``On the origin of quantum mechanics'', preprint, physics/0505181, May 2005, a simple atomic model based on a functional differential equation which reproduces the quantized Bohr atomic model was presented. The unique assumption was that the electrodynamic interaction has a finite propagation speed. In ``On the origin of the gravitational quantization: The Titius--Bode Law'', preprint, physics/0507072, Jul 2005, a simple gravitational model based on a functional differential equation which gives a gravitational quantification and an explanation of the modified Titius--Bode law is described. In ``On the origin of the anomalous precession of Mercury's perihelion'', preprint, physics/0510086, Oct 2005, an explanation of the anomalous precession of Mercury's perihelion is given in terms of a simple retarded potential, which, at first order, coincides with Gerber's potential of 1898, and which agrees with the author's previous works. In this paper, it is shown how the simple retarded potential presented in physics/0510086 also gives the correct value of the gravitational deflection of fast particles of General Relativity.Comment: 10 pages, 2 figure

Route to turbulence in a trapped Bose-Einstein condensate

We have studied a Bose-Einstein condensate of $^{87}Rb$ atoms under an oscillatory excitation. For a fixed frequency of excitation, we have explored how the values of amplitude and time of excitation must be combined in order to produce quantum turbulence in the condensate. Depending on the combination of these parameters different behaviors are observed in the sample. For the lowest values of time and amplitude of excitation, we observe a bending of the main axis of the cloud. Increasing the amplitude of excitation we observe an increasing number of vortices. The vortex state can evolve into the turbulent regime if the parameters of excitation are driven up to a certain set of combinations. If the value of the parameters of these combinations is exceeded, all vorticity disappears and the condensate enters into a different regime which we have identified as the granular phase. Our results are summarized in a diagram of amplitude versus time of excitation in which the different structures can be identified. We also present numerical simulations of the Gross-Pitaevskii equation which support our observations.Comment: 6 pages, 3 figure