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Remote Sensing Technique
Published in Ajai, Rimjhim Bhatnagar, Desertification and Land Degradation, 2022
Before going into further details of the concept of remote sensing and its elements, it is important to get an insight into what do we mean by electromagnetic radiation. Electromagnetic radiation is a type of energy that is propagated through free space or through a medium in the form of EM waves. It has been established that the charged particles create a time-varying electric field (EF) which induces a time-varying magnetic field (MF) in the surrounding medium. This changing magnetic field further produces changing electric field and so on. Together, they propagate as EM waves. Since a time-varying EF creates a time-varying MF and vice versa the EM wave is self-propagating. The directions of these fields are perpendicular to each other and to the direction of propagation when propagating through a homogeneous-isotropic media and are thus transverse in nature. Like any other waves, EM waves are characterized by frequency (ν), wavelength (λ), speed (c), intensity, the plane of polarization and direction of propagation. Like any other wave, they get reflected, refracted, diffracted and cause interference. In free space, EM waves travel at the speed of ~3 × 108 m/s. This is the ultimate speed any object can achieve.
Petroleum Geo-Electrical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
‘Electromagnetic radiation’ and ‘electromagnetic wave’ have same meaning. Electromagnetic radiation is the wave of electromagnetic fields, propagating in space, carrying electrical as well as magnetic radiation energy. The electromagnetic waves are generated by the up and down motion of the charged particles (electrons), in the direction of the wave progression. The vibrating charged electron particles create an oscillatory electric/magnetic field as a ‘halo’ around the propagating wave. The electromagnetic wave possesses dual properties of ‘particles’ and ‘waves’ simultaneously: Particle motion imparts mechanical properties in the propagating wave.Electrical and magnetic fields are generated along electromagnetic wave propagation line. It may be noted that a neutral field is created along the seismic wave propagation path.
The Use of Microwaves, Plasma and Laser for Wood Modification
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
The propagation of radiation is described by Maxwell’s equations and consists of an electric and magnetic field that oscillate at right angles to each other and to the direction of movement. Electromagnetic radiation is created when an atomic particle, such as an electron, is accelerated by an electric field, causing it to move. The movement produces oscillating electric and magnetic fields, which travel at right angles to each other in a bundle of light energy called a photon (Figure 4.3). Photons travel in harmonic waves at the fastest speed possible in the universe: 299,792,458 metres per second in a vacuum, also known as the speed of light (c). The waves have certain characteristics, given as frequency, wavelength or energy. A wavelength is the distance between two consecutive peaks of a wave and is given in metres (m) or fractions thereof Frequency is the number of waves that form in a given length of time. It is usually given as hertz, the number of wave cycles per second (Hz).
A simple method for obtaining artificial 3D forms of 2D mammograms in diagnosis of breast cancer
Published in The Imaging Science Journal, 2023
Computerized tomography and X-rays are used for the diagnosis of diseases in medical images. X-rays are electromagnetic rays and follow the rules of electromagnetic radiation. Electromagnetic radiation carries radiant energy through space with waves and photons, such as radio waves, visible light, or microwaves [31]. The main reason why X-rays are used in medical imaging is their ability to pass through tissue. The fluorescence and photographic properties allow the image to be obtained. Since the human body consists of tissues of different atomic weights and different thicknesses and densities, the absorption of X-rays will also be different. As a result of different absorption and penetration, X-rays falling on the x-ray film (roentgenogram) at different rates form an image of the body part they pass through. This image consists of gray tones ranging from black to white [32]. This information was our starting point in this study. Accordingly, the main question is: Is it possible to better visualize the change in textures of an image by looking at it from different viewpoints, and can these images provide us with more information?
Non-similar solution of mixed convection flow of viscous fluid over curved stretching surface with viscous dissipation and entropy generation
Published in Numerical Heat Transfer, Part B: Fundamentals, 2023
Sami Ul Haq, Muhammad Bilal Ashraf
In a viscous fluid flow, the irreversible process in which kinetic energy, which arises from the motion of the fluid, is transformed into internal energy. This process is known as viscous dissipation. The effect of thermal radiation on convective heat transport is studied in depth due to the flow involving high temperature with radiative heat flux. The thermal motion of charged particles produces thermal radiation, which is a form of electromagnetic radiation. Some important applications of such flows are in nuclear reactor and power plant, gas turbine, thermal energy storage and different propulsion systems for airplanes, missiles, etc. Abbas et al. [15] discussed the thermal radiation effect of nanofluid due to curved surface in the presence of applied magnetic field. Naveed et al. [16] presented the nonlinear thermal radiation on the hybrid nanofluid transport as a result of the curved stretched sheet. Furthermore, the effect of heat radiation on various types of fluid model owing to the curved stretched sheet see ref. [17, 18]. Sagheer et al. [19] discussed the impacts of the MHD flow of Maxwell nanofluid flow over convectively heated surface in the presence of non-uniform heat generation. Shah et al. [20] provided the numerical study of convective flow of three dimensional Maxwell nanofluid over stretching surface with nonlinear thermal radiation effect. In the last decade, many researchers [13, 21–23] identified the flow of non-Newtonian fluid over a curved stretching surface.
Focal therapy for localized cancer: a patent review
Published in Expert Review of Medical Devices, 2021
Jette Bloemberg, Luigi Van Riel, Dimitra Dodou, Paul Breedveld
Electromagnetic radiation can be described as a wave or a collection of particles, known as photons [44]. We classified focal therapy instruments using electromagnetic radiation as instruments using energy instead of matter, because photons possess no rest mass. The electromagnetic spectrum can be divided into non-ionizing and ionizing radiation. The boundary between non-ionizing and ionizing radiation occurs in the ultraviolet field but is not strictly defined [45]. Ionizing radiation causes chemical bonds to break by removing electrons, whereas non-ionizing radiation only causes heating of the substance [45]. Ionizing radiation causes cell death by depositing energy in cancer cells, thereby damaging their genetic material [46]. Instruments have been developed using different types of ionizing radiation, including X-ray radiation [47–49], gamma-radiation [50], and light radiation [51,52].