China
Africa
Explore chapters and articles related to this topic
Introduction
Published in Shoogo Ueno, Tsukasa Shigemitsu, Bioelectromagnetism, 2022
Shoogo Ueno, Tsukasa Shigemitsu
Foremost, the terminology which will be used and discussed later in this chapter will be introduced. Hans Christian Oersted showed that electricity and magnetism are two related mechanical phenomena. To explain this, he used for the first time the term “electromagnetism.” Afterward, Michael Faraday gave an explanation and meaning to this phenomenon and used the term “electromagnetism” which soon became established as a common scientific term. After their findings and discussions were published, the scientific knowledge in electromagnetism improved. This led to a better understanding of the basic electromagnetic phenomena found in bioelectromagnetism. Electromagnetism is a part of science that includes electricity, magnetism and electromagnetic fields phenomena. Biolectromagnetism is the study of how electromagnetism interacts with biological processes produced by cells, tissues and organisms.
Review of Nanopharmaceuticals
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Magnetism is a basic property of all matter associated with the movement of electric charges. Any wire conducting an electric current, independent on whether it is a direct current (DC) or alternating current, (AC) is surrounded by an invisible field called a magnetic field which exerts an unseen force on any object exposed to it. It is said that in 1820, during an evening lecture about electricity, the Danish scientist Hans Oersted discovered by chance that a compass needle was deflected from its position once a wire carrying electric current came close to it. Turning off the current but keeping the wire in place allowed the compass needle to return back to its original position. You can also send electric currents in the same direction through two parallel wires, and you will see both wires are attracted to each other; they will move towards each other as if driven by an invisible force. Oersted’s discovery triggered the development of the theory of electromagnetism, which in general describes the production of a magnetic field by an electric current flowing through a conductor. If a DC is sent through a wire, the strength of the induced magnetic field around that wire remains constant; in the case of AC, the produced electromagnetic field is periodically growing and shrinking due to the constantly changing current in the wire.
Basic Concepts of Magnetism
Published in Warsame Hassan Ali, Samir Ibrahim Abood, Matthew N. O. Sadiku, Fundamentals of Electric Machines, 2019
Warsame Hassan Ali, Samir Ibrahim Abood, Matthew N. O. Sadiku
Quantitative studies of magnetic phenomena initiated in the eighteenth century by Frenchman Charles Coulomb (1736–1806), who established the inverse square law of force, which states that the attractive force between two magnetized objects is directly proportional to the product of their individual fields and inversely proportional to the square of the distance between them. Danish physicist Hans Christian Oersted (1777–1851) first suggested a link between electricity and magnetism. Experiments involving the effects of magnetic and electric fields on one another were then conducted by Frenchman Andre Marie Ampere (1775–1836) and Englishman Michael Faraday (1791–1869), but it was the Scotsman, James Clerk Maxwell (1831–1879), who provided the theoretical foundation to the physics of electromagnetism in the nineteenth century by showing that electricity and magnetism represent different aspects of the same fundamental force field. Then, in the late 1960s, American Steven Weinberg (1933–) and Pakistani Abdus Salam (1926–), performed yet another act of theoretical synthesis of the fundamental forces by showing that electromagnetism is one part of the electroweak force.
Green-based bio-synthesis of nickel oxide nanoparticles in Arabic gum and examination of their cytotoxicity, photocatalytic and antibacterial effects
Published in Green Chemistry Letters and Reviews, 2021
Zahra Sabouri, Alireza Akbari, Hasan Ali Hosseini, Mehrdad Khatami, Majid Darroudi
Considering how NiO-NPs belong to the category of magnetic nanoparticles, it is essential to study their magnetic properties. In the current paper, the magnetic nature of NiO nanoparticles was examined throughout the magnetic field of +20,000 to–20,000 Oersted by the application of VSM analysis. Figure 8 demonstrates the hysteresis curve of nanoparticles, which were calcinated at the temperature of 400°C in the magnetic field (H) of +20,000 to −20,000 Oersted. Given this curve and intensity of magnetization, it can be concluded that the nanoparticles were superparamagnetic. Due to the absence of hysteresis loop throughout the M-H curves and coercive field (Hc = 0), while the remanent magnetization (Mr = 0) equaled to zero and reached a state of full saturation, it can be indicated that the nanoparticles contained superparamagnetic properties (62). Furthermore, the saturation magnetization (Ms) value of this compound was about 23 emu/g, which stands as a proof of the strong magnetic properties of this compound (63).
Magnetic hetero-structures as prospective sorbents to aid arsenic elimination from life water streams
Published in Water Science, 2018
Anuradha Jabasingh S., Ravi T., Abubeker Yimam
Magnetic nanoparticles remain the spotlight as they were triumphant for the separation of toxic metal ions from different sources. Feng et al. (2012) reported super paramagnetic high surface area Fe3O4 nanoparticles for arsenic removal (Feng et al., 2012). Mayo et al. (2007) studied the effect of nanocrystalline magnetite size on arsenic removal. Remediation of organic and inorganic arsenic contaminated groundwater was carried out using a nanocrystalline TiO2 based adsorbent by Jing et al. (2009). Magnetic multi-granule nanoclusters (MGNCs) were investigated to successfully remove arsenic from aqueous environment. The researchers, herein, have extensively studied the magnetic coercivity (Hc), measured in Oersted (Oe) or ampere/meter(A/m) of the magnetic multi-granule nanoclusters and its effect on the magnetic saturation. Magnetic coercivity refers to the measure of the ability of a ferromagnetic material to endure an external magnetic field devoid of becoming demagnetized. In this case, the magnetic saturation (MS) values were measured at a temperature of 300 K and a magnetic coercivity value of 70 kOe. The magnetic saturation values in emu/g (electromagnetic unit per gram) were found to be 73.9, 80.3, and 84.6 emu/g for MGNC’s of 100, 200, and 400 nm, respectively. The high MS value of multi-granule nanocluster (MGNC) samples at 100 nm was comparative to the MS values reported for Fe3O4 nanoparticles (Lee et al., 2014). MGNC’s used were stable ferro magnets in aqueous solution and their multi-granular structure allowed them to get homogeneously dispersed, hence displaying an increased number of surface functional groups (–OH). The research thus revealed the removal of the toxic heavy metal, arsenic from the contaminated groundwater containing 0.6 mg/L of arsenate using 1.0 g of 100 nm MGNCs. This limit was found to comply with the WHO permissible arsenic limit of 10 μg/ L in drinking water. Studies were conducted on the preparation and application of a magnetic composite (Mn3O4/Fe3O4) for removal of As(III) from aqueous solutions (Silva et al., 2012). The blend of an active high surface area sorbent (Mn3O4) with a magnetic phase (Fe3O4) allowed efficient As(III) removal and solid/liquid separation. γ-Fe2O3 nanoparticles were prepared by a wet chemical synthetic method whereby 860 mg of FeCl2·4H2O and 1400 mg of FeCl3 was dissolved in 170 mL of deionized water. This was followed by adding 10 M NaOH under intensive stirring. The color change was observed from orange to dark brown after the addition of NaOH. Subsequent stirring for 1 h, in water bath at 90 °C, allowed the separation of products by a simple hand magnet having a magnetic induction of ∼0.3 T (Kilianova et al., 2013).