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Introduction to Electric Motors
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Nuclear radiation, also known as ionizing radiation, is defined as energy transmission through certain kinds of ionizing particles and photons during nuclear reactions. Nuclear radiation includes α-rays, β-rays, x-rays, and the more energetic portion of the electromagnetic spectrum. Electric servomotors and drives used in nuclear power plants are subjected to nuclear radiation, high temperature, and high humidity. These severe environmental conditions can degrade the performance of the servo system in different ways: (a) The radiation with high-energy particles can demagnetize PMs in the motor [1.101, 1.102]. (b) Ionizing radiation can break down materials within electrical equipment (e.g., motors switches, incandescent lights, wiring, and solenoids). For instance, when wiring is exposed to γ-rays, no change is noticed until the wiring is flexed or bent. The wire’s insulation becomes brittle and may cause short circuits in the equipment [1.103]. (c) The gamma and neutron radiation can cause extensive damage to integrated circuit devices [1.104]. (d) Aging mechanisms could significantly affect electric motors/components. Under a nuclear radiation condition, aging effects are most commonly due to radiation exposure and heat, as well as other phenomena such as mechanical vibration and chemical degradation.
Energy and Environment
Published in T.M. Aggarwal, Environmental Control in Thermal Power Plants, 2021
Nuclear power is the use of nuclear reactions that release nuclear energy[5] to generate heat, which most frequently is then used in steam turbines to produce electricity in a nuclear power station. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently, the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form of geothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest.
Petroleum Pre-Period
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
A chemical element is a substance that cannot be broken into a smaller chemical substance, except in a nuclear reaction. The element is the simplest form of matter; the elements are produced by bonding among atoms of the same types. About 115 elements exist in the universe. Eighty-three elements occur naturally, and the rest are produced by artificial nuclear reaction. A nuclear reaction differs from a chemical reaction. A chemical reaction is the sharing of outer orbital electrons of the reactant atoms. The nucleus of the atom remains intact in a chemical reaction. Nuclear reactions are the fusion (combination) or fission (disintegration) of atomic nuclei. The change in nucleus composition (neutron and proton) generates new atoms with the release of large amounts of radiation. The fission reaction produces lower atomic mass atoms and fusion generates heavier atomic mass atoms. All nuclear reactions are exothermic, whereas chemical reactions are exothermic or endothermic.
Hot compressive deformation behaviour and constitutive equations of Mg–Pb–Al–1B–0.4Sc alloy
Published in Philosophical Magazine, 2021
Yuan Sun, Longke Bao, Yonghua Duan
Nuclear energy, as environmentally friendly and efficient energy, has attracted more and more attention [1–4]. However, when a nuclear reaction occurs, rays (neutrons, gamma rays, etc.) that are harmful to the human body and instruments were released. For the safe operation of nuclear reactions, it is very important to shield nuclear radiation. Therefore, with the widespread application of nuclear energy and nuclear technology, the research and development of nuclear shielding materials have become an inevitable trend. Currently, there are many types of nuclear shielding materials developed. Among these shielding materials, non-metallic inorganic materials such as graphite [5] and boron have a single structure and poor comprehensive shielding performance. Although concrete [6] has good thermal properties, it has a large mass and volume under certain shielding requirements. Lead has high density but low strength and low hardness, so it cannot be used as a structural material [7]. Polymer materials have a good fast neutron slowing function due to the presence of a large number of hydrogen elements but generally have poor thermodynamic properties [8]. Acosta et al. [9] believe that the combination of boron and lead is very suitable for nuclear shielding materials. B, Al and Mg elements were added to Pb, and the advanced Pb–Mg–Al–B material was prepared. The study found that the radiation shielding ability of Pb–Mg–Al–B material was higher than most existing shielding materials, even if it has a low lead and boron content [10]. Alloy grains can be significantly refined with the addition of rare earth elements, and industrial production often uses this method to prepare special alloys [11–15]. The rare earth Sc element can effectively refine the grains of Mg–11Zn alloy, and the high-temperature strength can be effectively improved by adding Sc (1 wt%) [16]. Therefore, this study improved the properties of Mg–Pb–Al–B alloy by adding a small amount of Sc (0.4 wt%) to the material.