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The mechanical career of Councillor Orffyreus, confidence man
In the early 18th century, J. E. E. Bessler, known as Orffyreus, constructed several wheels that he claimed could keep turning forever, powered only by gravity. He never revealed the details of his invention, but he ...
Tsunamis and Tsunami Hazards in Central America
A tsunami catalogue for Central America is compiled containing 49 tsunamis for the period 1539–1996, thirty seven of them are in the Pacific and twelve in the Caribbean. At the Caribbean side, 5 events are related with ...
A thermodynamic cycle for the solar cell
A solar cell is a heat engine, but textbook treatments are not wholly satisfactory from a thermodynamic standpoint, since they present solar cells as directly converting the energy of light into electricity, and the current ...
Irreversibility in an ideal fluid
When a real fluid is expelled quickly from a tube, it forms a jet separated from the surrounding fluid by a thin, turbulent layer. On the other hand, when the same fluid is sucked into the tube, it comes in from all ...
Chandler wobble: Stochastic and deterministic dynamics
We propose a model of the Earth’s torqueless precession, the “Chandler wobble,” as a self-oscillation driven by positive feedback between the wobble and the centrifugal deformation of the portion of the Earth’s mass contained ...
Diseño y caracterización de un enfriador de átomos de tipo “desacelerador Zeeman”
Nosotros presentamos un método que utiliza simultáneamente dos modelos matemáticos, con el objetivo de optimizar el diseño de un desacelerador Zeeman, con miras a la implementación de átomos ultrafríos a la física del ...
Relation between Luminescence and Electronic Surface Characteristics in p-type Porous Silicon
Measurements of photoluminescence, electronic surface states and effective surface area, at various stages of the anodization process, are presented. The results show a behavior different from that observed on n-type porous Si.
Pressure dependence of ferroelectric quantum critical fluctuation
Phase transitions to a long-range-ordered state driven by a softened phonon mode are ubiquitous across condensed matter physics, but the evolution of such a mode as the system is tuned to or from the transition has never ...