ABSTRACT
According to many scientists, there are some redundancies in the SI system of units. Through an entropy approach that depends on a previous analogy between the electrical, mechanical and thermal fields; it was possible to introduce a system of units that removes such redundancies. According to the second law of thermodynamics, the temperature was defined as a quality of heat. Following a proved analogy, the electrical and magnetic potentials may represent also the qualities of electric and magnetic fluxes. According to published experimental results, the electric and the magnetic potentials generates also electromotive forces, EMF, that were measured by Al-Fe thermocouples. The chemical potential or the concentration gradient generates also an EMF, as in the concentration cells, which is measured here by the same Al-Fe thermocouple. Such measurement-results are introduced to define a unique scale for measuring the potentials or qualities of the thermal, chemical, electric, and magnetic fields. The mentioned qualities are not defined by directly measurable quantities, as length and time, but they are found as functions of dimensionless concentrations of mass or energy fluxes. Hence, the volt, as a unit of the introduced EMF scale for potentials measurement, is postulated as a dimensionless unit. Finally, a universal system of units that is based only on three dimensions; L, T, and E, and four fundamental units; meter, second, Joule and volt is introduced in this paper to delete the SI redundancies. The energy replaces the mass as a fundamental unit in the introduced US as it plays a dominant role in most of the scientific and engineering fields. The ampere is not included as a fundamental unit since the charge is considered as a form of energy that is measured in one of the US fundamental units, Joule. The candela and the mole were also not considered as fundamental units as they can be related to the selected fundamental units by appropriate numbers. The limited number of dimensions in the introduced US simplifies the application of the “π” dimensional theorem to find plausible relations between the main parameters that characterize many physical phenomena and the energy conversions and interactions.