Daniel Radu

Dissipation and Thermal Time Constants in Graphite of an Ultra-Small Bead Thermistor

The thermistors are indispensable devices in experimental arrangements for electrical calibration of graphite calorimeters. The present experiments determine the two basic thermal constants in graphite – the thermal time constant, \( \tau_{g} \) and dissipation constant, \( \delta_{g} \) – of commercially-available VECO ultra-small bead thermistors; these constants are essential parameters in thermal modeling of graphite calorimeters. For the above-mentioned kind of thermistors, the dissipation constant in graphite is found to be approximately ten times larger than that in still air, whereas the thermal time constant in graphite is approximately one hundred times smaller than that corresponding to a thermistor placed in still air.

The Electromagnetic Field

The study of time-variable electric and magnetic fields showed the strong interdependence between them: a variable electric field produces a magnetic field and vice-versa.

Elements of Magnetofluid Dynamics

In the fourth decade of the 20th century appeared a new branch of physical sciences, as a border discipline between the electromagnetic field theory, on the one side, and the fluid mechanics, on the other, known as magnetofluid dynamics, or magnetohydrodynamics – MHD. By its object and applications, this discipline can be included in the larger framework of plasma physics.

Fields of Stationary Currents

If at the ends A and B (or at any two points) of a conductor is applied a potential difference or voltage, this will produce in the conductor an oriented displacement of electric charges.

General Theory of Relativity

Einstein developed his ideas about the relativistic approach to gravity over many years, culminating with his 1915 papers presented to the Prussian Academy of Science.

Relativistic Formulation of Electrodynamics in Minkowski Space

Consider a charged particle of mass \(m_0\) and charge e, moving in the electromagnetic field \({\mathbf {E}},\,{\mathbf {B}}\), defined in terms of the usual electromagnetic potentials \(V,\,{\mathbf {A}}\).