Principles of Microwave Radiation

1980 ◽  
Vol 43 (8) ◽  
pp. 618-624 ◽  
Author(s):  
B. CURNUTTE
Keyword(s):  
Electromagnetic Radiation ◽  
Microwave Radiation ◽  
Food Processing ◽  
Electromagnetic Waves ◽  
Ultra Violet ◽  
X Rays ◽  
Radio Waves ◽  
Dual Nature ◽  
Ultra Violet Radiation ◽  
Transmission And Absorption

Microwaves, such as those used in cooking and processing food, are part of the broad spectrum of electromagnetic radiation which includes radio waves, microwaves, infrared radiation, visible light, ultra-violet radiation, x-rays and Gamma rays. Electromagnetic radiation has a dual nature, it is both wave-like and particle-like. An understanding of this dual nature of electromagnetic radiation is necessary for an understanding of the processes of emission, transmission and absorption of microwaves, which is in turn necessary for understanding the processes and phenomena which are important in the use of microwave radiation as a source of energy for heating and food processing. The properties of electromagnetic waves and the processes of emission. transmission and absorption are described and some effects in microwave-heating applications are discussed.

6. Electromagnetic waves

2018 ◽  
pp. 70-99
Author(s):  
Mike Goldsmith
Keyword(s):  
Electromagnetic Radiation ◽  
Infrared Radiation ◽  
Electromagnetic Waves ◽  
Scientific Investigation ◽  
The Other ◽  
Electromagnetic Spectrum ◽  
X Rays ◽  
Radio Waves ◽  
History Of ◽  
Insight Into

‘Electromagnetic waves’ considers the history of the scientific investigation into the electromagnetic spectrum, including Einstein’s insight into the quantized nature of electromagnetic radiation. It explains that the only difference between light, radio waves, and all the other forms of electromagnetic radiation is the length of the fictitious-but-convenient waves or, equivalently, the energy of the photons involved. These different energies lead to different mechanisms for the formation and absorption of the different kinds of radiation, and it is this which gives rise to their different behaviours. Radio waves, microwaves, infrared radiation, light, ultraviolet light, X-rays, and gamma rays are all discussed.

4. Windows in the sky

2016 ◽  
pp. 39-46
Author(s):  
Geoff Cottrell
Keyword(s):  
Solar Radiation ◽  
Electromagnetic Radiation ◽  
Electromagnetic Waves ◽  
Outer Space ◽  
Cosmic Ray ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Radio Waves ◽  
Transverse Waves ◽  
The Universe

The atmosphere influences much of what can be seen through a telescope. Most of the atmosphere lies within 16 km from the Earth’s surface. Further out, the air becomes thinner until it merges with outer space. In the ionosphere—a layer 75–1000 km high—neutral atoms are ionized by solar radiation and high-energy cosmic ray particles arriving from distant parts of the Universe. ‘Windows in the sky’ explains electromagnetic radiation and the electromagnetic spectrum from gamma rays through to visible light and radio waves. Electromagnetic waves are transverse waves that can be polarized. The atmosphere acts as a filter and blocks cosmic electromagnetic radiation. Atmospheric turbulence distorts starlight resulting in ‘twinkling’ stars.

Structure of the Atom

2009 ◽  
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Electronic Structure ◽  
Electromagnetic Radiation ◽  
Characteristic Frequency ◽  
Wave Number ◽  
X Rays ◽  
Radio Waves ◽  
Light Wavelength ◽  
Speed Of Light ◽  
Continuous Stream ◽  
Unit Of Length

The arrangement of electrons around the nucleus of an atom is known as its electronic structure. Since electrons determine all the chemical and most physical properties of an atomic system, it is important to understand the electronic structure. Much of our understanding has come from spectroscopy, the analysis of the light absorbed or emitted by a substance. Electromagnetic radiation is a form of energy; light is the most familiar type of electromagnetic radiation. But radio waves, microwaves, X-rays, and many other similar phenomena are also types of electromagnetic radiation. All these exhibit wavelike properties, and all travel through a vacuum at the speed of light. The wavelike propagation of electromagnetic radiation can be described by its frequency (ν), wavelength (λ), and speed (c). Wavelength (lambda, λ): The wavelength of a wave is the distance between two successive peaks or troughs. Frequency (nu, ν): The frequency of a wave is the number of waves (or cycles) that pass a given point in space in one second. The unit is expressed as the reciprocal of seconds (s−1) or as hertz (Hz). A hertz is one cycle per second (1 Hz = 1 s−1). Speed of light (c): The speed of light in a vacuum is one of the fundamental constants of nature, and does not vary with the wavelength. It has a numerical value of 2.9979 × 108 m/s, but for convenience we use 3.0 × 108 m/s. These measurements are related by the equation: Speed of light =Wavelength×Frequency c = λν This expression can be rearranged to give: λ = c/v, or ν = c/λ Wave number (⊽): The wave number is a characteristic of a wave that is proportional to energy. It is defined as the number of wavelengths per unit of length (usually in centimeter, cm).Wave number may be expressed as ⊽ =1/λ While electromagnetic radiation behaves like a wave, with characteristic frequency and wavelength, experiment has shown that electromagnetic radiation also behaves as a continuous stream of particles or energy packets.

scholarly journals REVIEW OF THE INFLUENCE OF ELECTROMAGNETIC RADIATIONS OF DIFFERENT RANGE ON THE PHYSIOLOGICAL PROCESSES OF HUMAN AND ANIMAL SPERMATOZOA

2021 ◽  
pp. 42-54
Author(s):  
D.V. Zadubenko ◽  
D.N. Sultanova ◽  
M.I. Pak ◽  
I.M. Kim ◽  
E.К. Kilina ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Experimental Studies ◽  
Reproductive Function ◽  
X Rays ◽  
Radio Waves ◽  
Biochemical Processes ◽  
Male Reproductive Function ◽  
Physiological Processes ◽  
Negative Effect

This review presents 40 experimental studies of the effect of electromagnetic radiation of various ranges on the male reproductive function of humans and other vertebrates. The review includes works performed in the period from 2010 to 2020. Currently, not only the negative effect of radio waves, X-rays and gamma radiation has been shown, but many experiments have been carried out, where with the help of electromagnetic radiation it is possible to favorably influence spermatogenesis in general and physiological, biochemical processes in spermatozoa in particular. The purpose of this bibliographic study was to search for options for exposure to electromagnetic radiation to modulate the biological processes of spermatogenesis and sperm motility in vitro.

Efficiency of Liquidation of Biotic Pests Using Microwave Radiation

2013 ◽  
Vol 688 ◽  
pp. 27-36 ◽  
Author(s):  
Miloslav Novotný ◽  
Jan Škramlík ◽  
Karel Šuhajda ◽  
Jindřich Sobotka ◽  
Jan Gintar ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Electric Field ◽  
Electromagnetic Radiation ◽  
Microwave Radiation ◽  
Industrial Application ◽  
Electromagnetic Waves ◽  
Water Molecules ◽  
Direct Irradiation

Microwaves are electromagnetic waves of frequencies from 300 MHz to 300 GHz, corresponding to wavelengths from 1 m to 1 mm. For industrial application is allowed more frequencies, but we are mainly interested in the frequency 2 450 MHz, a wavelength of 12,2 cm, which we use in our applications. The heating occurs so that the electric field in the water molecules orient themselves according to polarization. Microwaves are a classical electromagnetic radiation with frequency lower than the solar radiation and therefore leave no residual radiation harmful to health. Using the device is completely safe, damage to health can occur only by direct irradiation of a few cm for several minutes, either intentionally or careless handling of the machine.

scholarly journals The measurement of actinic erythema produced by ultra-violet radiation with special reference to the latent time

1931 ◽  
Vol 108 (757) ◽  
pp. 258-263 ◽  
Keyword(s):  
Quantitative Study ◽  
Ultra Violet ◽  
Biological Action ◽  
X Rays ◽  
Physical Stimulus ◽  
Ultra Violet Radiation ◽  
Latent Time ◽  
Skin Erythema ◽  
Γ Rays ◽  
Violet Radiation

The quantitative study of the biological action of radiation is generally considered difficult in the case of skin erythema, and results obtained by different workers using ultra-violet radiation to produce the erythema are often contradictory. Much quantitative work has been done to ascertain how far any biological action runs parallel with the amount of physical stimulus, but this has usually been done on plants, histological sections of tumours, cultures, albumen, etc., and using more ofter γ-rays and X-rays than the longer ultra-violet rays. The present paper is preliminary to further study, and is concerned with the precautions necessary to obtain reliable and consistent measurements of the amount of skin erythema resulting from exposure to ultra-violet rays.

scholarly journals Morphophysiological and Proteomic Responses on Plants of Irradiation with Electromagnetic Waves

2021 ◽  
Vol 22 (22) ◽  
pp. 12239
Author(s):  
Zhuoheng Zhong ◽  
Xin Wang ◽  
Xiaojian Yin ◽  
Jingkui Tian ◽  
Setsuko Komatsu
Keyword(s):  
Gamma Rays ◽  
Communication Systems ◽  
Electromagnetic Waves ◽  
Insect Pests ◽  
Electromagnetic Energy ◽  
Fertilizer Efficiency ◽  
Future Research ◽  
X Rays ◽  
Radio Waves ◽  
Wide Range

Electromagnetic energy is the backbone of wireless communication systems, and its progressive use has resulted in impacts on a wide range of biological systems. The consequences of electromagnetic energy absorption on plants are insufficiently addressed. In the agricultural area, electromagnetic-wave irradiation has been used to develop crop varieties, manage insect pests, monitor fertilizer efficiency, and preserve agricultural produce. According to different frequencies and wavelengths, electromagnetic waves are typically divided into eight spectral bands, including audio waves, radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. In this review, among these electromagnetic waves, effects of millimeter waves, ultraviolet, and gamma rays on plants are outlined, and their response mechanisms in plants through proteomic approaches are summarized. Furthermore, remarkable advancements of irradiating plants with electromagnetic waves, especially ultraviolet, are addressed, which shed light on future research in the electromagnetic field.

1. Waves in essence

2018 ◽  
pp. 1-29
Author(s):  
Mike Goldsmith
Keyword(s):  
Phase Velocity ◽  
Electromagnetic Radiation ◽  
Particle Velocity ◽  
Electromagnetic Waves ◽  
Seismic Waves ◽  
Fundamental Difference ◽  
Radio Waves ◽  
Transverse Waves ◽  
The Difference ◽  
Wave Phenomena

Most waves can be defined by just a few parameters: period, frequency, wavelength, amplitude, particle velocity, phase velocity, and group velocity. ‘Waves in essence’ explains these parameters in turn and then goes on to discuss the spreading and fading of waves and the complexities of waves that arise through their interactions with objects and other waves resulting in diffraction and interference. It also describes the difference between longitudinal and transverse waves and the important wave phenomena of refraction and reflection. It then outlines the fundamental difference between pressure waves like sound, ocean, and seismic waves, and electromagnetic waves, which include light and radio waves. All electromagnetic radiation is made of particles called photons.

The Induction by Mustard Gas of Chromosomal Instabilities in Drosophila melanogaster.

1945 ◽  
Vol 62 (3) ◽  
pp. 307-320 ◽  
Author(s):  
C. Auerbach
Keyword(s):  
Ultra Violet ◽  
Pollen Grains ◽  
Mutagenic Action ◽  
Mustard Gas ◽  
X Rays ◽  
Induced Mutations ◽  
Ultra Violet Radiation ◽  
The One ◽  
Mutagenic Effects ◽  
Chromosomal Instabilities

The discovery (Auerbach, 1943, 1946; Auerbach and Robson, 1946, 1947) that mustard gas is comparable to X-rays and similar physical agencies in its ability to produce mutations and chromosome rearrangements has opened up a new line of approach to the problem of gene mutation. It is to be expected that a comparative study of the mechanism by which chemical substances on the one hand and physical agencies on the other exercise their mutagenic effects, will further our understanding of the process of mutation itself. One of the first questions to be tackled in the early days of radiation genetics was the possibility of a delayed mutagenic action of irradiation (Muller, 1927; Timoféeff-Ressovsky, 1930, 1931; Grüneberg, 1931). The bulk of the evidence (see, however, Bishop, 1942) indicates that X-ray-induced mutations and chromosome breaks arise as an immediate effect of the irradiation, although after treatment of mature spermatozoa new recombinations of broken chromosomes may be delayed until the spermatozoon has entered the egg. Data obtained by Stadler (1939) suggest that after ultra-violet radiation of pollen grains the mutational process often is not completed before the treated chromosome has split into its two daughter chromatids. This results in a high proportion of mosaics. A similarly high proportion of mosaics has been found in the progeny of Drosophila ♂♂ which had been treated with mustard gas (Auerbach, 1946; Auerbach and Robson, 1946). This raises the question of a possible delayed action of the chemical mutagenic treatment.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

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