China
Africa
Explore chapters and articles related to this topic
Nuclear Power
Published in Robert Ehrlich, Harold A. Geller, John R. Cressman, Renewable Energy, 2023
Robert Ehrlich, Harold A. Geller, John R. Cressman
The strength of 1 for the strong force is an arbitrary choice. Note the extreme weakness of the gravitational force compared to all the other three, which is why gravity is of no significance when considering nuclear reactions. There is one other fundamental force known as the weak force, which does come into play inside the nucleus but, like the strong force, has no role outside it given its short range. In particle physics, all forces are assumed to be mediated by exchanged particles. Thus, as indicated in Table 3.2, the force of an electron on another electron is due to photons exchanged between them. The exchanged particles, however, are not observed, and are referred to as “virtual” particles in contrast to “real” particles that are observed in detectors. In recent years, good arguments have been presented to show that at sufficiently high energies, all the four fundamental forces become unified.
Nuclear Power
Published in Robert Ehrlich, Harold A. Geller, Renewable Energy, 2017
Robert Ehrlich, Harold A. Geller
The strength of 1 for the strong force is an arbitrary choice. Note the extreme weakness of the gravitational force compared to all the other three, which is why gravity is of no significance when considering nuclear reactions. There is one other fundamental force known as the weak force, which does come into play inside the nucleus but, like the strong force, has no role outside it given its short range. In particle physics, all forces are assumed to be mediated by exchanged particles. Thus, as indicated in Table 3.2, the force of an electron on another electron is due to photons exchanged between them. The exchanged particles, however, are not observed, and are referred to as “virtual” particles in contrast to “real” particles that are observed in detectors. In recent years, good arguments have been presented to show that at sufficiently high energies, all the four fundamental forces become unified.
Radioactive Materials and Radioactive Decay
Published in Robert E. Masterson, Nuclear Engineering Fundamentals, 2017
As long as the virtual particles that are created in such a reaction do not exist for a period of time Δt greater than that required by the Heisenberg uncertainty principle ΔEΔt ≥ h (see Chapter 2), then energy in the reaction is conserved, and momentum is conserved as well. The final result of the reaction remains unchanged. Again, before leaving this interpretation, it is helpful to keep in mind that ordinary β− decay only tends to occur in neutron-rich nuclei, which depart somewhat from the ideal 1.5 to 1 neutron to proton ratio. In spent nuclear fuel rods, these nuclei are always present in great abundance. However, their actual decay times may vary by several orders of magnitude from one isotope to the next. This is determined by the force imbalances within the individual nuclei themselves and is consistent with the data we have already presented in Table 6.1.
Quantization of magnetoelectric fields
Published in Journal of Modern Optics, 2019
Circularly polarized EM photons carry a spin angular momentum. EM photons can also carry an additional angular momentum, called an orbital angular momentum. Azimuthal dependence of beam phase results in a helical wavefront. The photons, carrying both spin and orbital angular momentums are twisted photons (4). The twisted EM photons are propagating-wave, ‘actual’, photons. In the near-field phenomena, which are characterized by subwavelength effects and do not radiate though space with the same range properties as do EM wave photons, the energy is carried by virtual EM photons. Virtual particles should also conserve energy and momentum. The question whether virtual EM photons can behave as twisting excitations is a subject of a strong interest. Recently, a new concept of the spin–orbit interactions in the evanescent-field region of optical EM waves has been proposed. It was shown that an evanescent wave possesses a spin component, which is orthogonal to the wave vector. Furthermore, such a wave carries a momentum component, which is determined by the circular polarization and is also orthogonal to the wave vector. The transverse momentum and spin push and twist a probe Mie particle in an evanescent field. This should allow the observation of ‘impossible’ properties of light, which was previously considered as ‘virtual’ (5,6). The newly discovered transverse spin angular momenta appearing in various field structures are actively discussed in theory and observed in experiments (7–10). In connection with this subject, the reviews in (11–13) are also useful.