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The mechanical career of Councillor Orffyreus, confidence man
(2013-05)
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 ...
Irreversibility in an ideal fluid
(2014-10)
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
(2016-09-18)
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 ...
Exact Solutions of a Chaplygin Gas in an Anisotropic Space-Time of Petrov D
(2017)
This document obtains two exact solutions to the anisotropic spacetime of Petrov D by using the model of a perfect fluid. These solutions represent a scenario of a universe in which the pressure P and the energetic density ...
Exact solution of an ekpyrotic fluid and a primordial magnetic field in an anisotropic cosmological space-time of Petrov D
(2017)
This document obtained and analyzed an exact solution of an ekpyrotic fluid (P = 5/3 µ) and a primordial magnetic field, so that the latter does not induce currents or electric fields. It is determined that the main role, ...
The early rainy season in Central America: the role of thetropical North Atlantic SSTs
(2016)
We explored the relationship between the precipitation anomalies during May to June as the first peak of the rainy season in the Pacific slope of Central America, and sea surface temperature (SST) fluctuations in the ...
Cosmological Exact Solutions Set of a Perfect Fluid in an Anisotropic Space-Time in Petrov Type D
(2016-06)
In this document a set of exact solutions is obtained by using the model of a perfect fluid on an homogeneous and anisotropic space-time that belongs to (Local Rotational Symmetry) Petrov’s type D. This solutions represent ...
Interaction of a quantum field with a rotating heat bath
(2018-08-01)
The linear coupling of a rotating heat bath to a quantum field is studied in the framework of the Markovian master equation for the field's non-unitary time evolution. The bath's rotation induces population inversion for ...
Study of oxide bands in p-type porous silicon layers
(2019)
The interest in developing fast and reliable chemical and biochemical sensors in an inexpensive way is something that has attracted a lot of efforts in the last decades. One of the potential material candidates is ...