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Extraction of Fatty Acids and Micronutrients from Agro-Industrial Waste and their Application in Nutraceuticals and Cosmetics
Published in Anil Kumar Anal, Parmjit S. Panesar, Valorization of Agro-Industrial Byproducts, 2023
Phan Thi Phuong Thao, Lai Phuong Phuong Thao, Tran Quoc Toan, Tran Thi Thu Hang
Microwaves are non-ionizing electromagnetic waves with frequencies ranging from 300 MHz to 300 GHz (much higher than ultrasound wave frequencies). With the nature of electromagnetic radiation, microwaves have similar properties as visible light, i.e., they may be absorbed or reflected by material. There are also some mediums transparent to microwaves; in this case, microwaves may transmit through the medium without any absorption. The absorption of microwaves by a dielectric material results in the transfer of energy from the microwaves to the substance, resulting in an increase in temperature.
State Estimation
Published in M. Necati Özisik, Helcio R. B. Orlande, Inverse Heat Transfer, 2021
M. Necati Özisik, Helcio R. B. Orlande
The use of heat for the treatment of cancer can be aimed at: (i) A mild temperature increase of the tumor, in order to make their cells more susceptible to the effects of other treatments, like radiotherapy or chemotherapy; or (ii) a large temperature increase of the tumor to kill their cells solely by the effects of heat. Within the medical community, these treatments are usually referred to as hyperthermia and thermal ablation, respectively. The hyperthermia treatment of cancer consists in raising tumor tissues to temperatures between 41°C and 47°C during a pre-specified period of time. Among other types of heating, electromagnetic energy sources in the radiofrequency and near-infrared ranges have been used to deliver energy to the target region, due to the biological windows of human tissues that exhibit small absorption. One major problem of the hyperthermia treatment of cancer is the lack of selectivity of the heating procedure. On the other hand, with recent advancements in nanotechnology, nanoparticles have been used as absorbing agents in the near-infrared and in the radiofrequency ranges, in order to provide localized thermal damage to the tumor, with minimal damage to the healthy cells [205–210].
Spectrophotometry
Published in Ernő Pungor, A Practical Guide to Instrumental Analysis, 2020
The subject of spectrophotometry is to study interactions between electromagnetic radiation and matter. If an electromagnetic radiation acts upon a piece of matter and there is selective absorption, the material will absorb different amounts of the components of the radiation of different wavelengths. The change in the degree of absorption as a function of wavelength is the absorption spectrum. The latter is characteristic of the quality of the material. The degree of absorption of light of a given wavelength enables a conclusion to be drawn on the amount of the material under test. The basis of quantitative determination is Beer’s law: A=lgI0I=εcl
Deposition of electrically-conductive polyaniline/ferrite nanoparticles onto the polypropylene nonwoven for the development of an electromagnetic interference shield material
Published in The Journal of The Textile Institute, 2022
Ali Erdem Yörük, Meryem Kalkan Erdoğan, Meral Karakışla, Mehmet Saçak
EMI is emitted in waves containing natural or artificial frequency components in a wide range from low power frequencies such as radio to the microwave region and negatively affects electrical devices' performance. It occurs between communication, automation, business control unit and causes valuable time, energy, and resource loss. The damages of EMI are not limited to electronic devices but also pose a risk to human health. For example, if a person is exposed to electromagnetic waves, vascular networks may be affected due to the accumulation of heat in sensitive organs such as the eye, which cannot be easily removed (Jagatheesan et al., 2014; Lai et al., 2007). It has been reported that it increases leukemia and other types of cancer and even causes short-term infertility when exposed to low-intensity electromagnetic (EM) waves (French et al., 2001). Considering these damages of EMI, it is noteworthy to take cautions against EMI. The EMI shielding process limits the electromagnetic fields' direction to space with a barrier made up of conductive materials (Maity et al., 2013; Moon et al., 2013). Electromagnetic waves consist of electric and magnetic fields that oscillate vertically towards each other and the growth direction of energy. These electric and magnetic fields of electromagnetic waves can be captured by reflection and absorption, and protection against EMI can be provided. Therefore, a conductive material against EMI ensures shielding by reflection at low frequencies and absorption at high frequencies requiring more attention (Jagatheesan et al., 2014).
An experimental study of the effects of climate conditions on thermography and pavement assessment
Published in International Journal of Pavement Engineering, 2021
The temperature of most materials rises due to a variety of effects including the radiation absorption. All objects with temperatures greater than absolute zero are emitters of infrared (IR) energy (Clark et al. 2003). This energy can be measured using infrared thermal cameras. However, the surrounding weather condition can have a great effect on the measurement of this energy use. Current thermography-related research publications and studies have asserted these effects (ASTM D4788-88 2001, Rumbayan and Washer 2014, Milovanovic and Nanjad 2016). However, not many researchers have tried to quantify them. In addition, it has not been the subject of many researches to study the limitation of the utilisation of IRT imaging tools for NDT due to alterations of the results caused by different weather conditions. These phenomena are the basis of a series of tests that were conducted to study the effect of different weather conditions and crack profiles on the workability of the thermal camera and its ability to record the emitted IR energy.
Dielectric properties and electromagnetic wave absorbing performance of granular polysilicon during 2450 MHz microwave smelting
Published in Journal of Microwave Power and Electromagnetic Energy, 2021
Jin Lin, Fucheng Zhang, Yongzhen Bai, Xiaobiao Shang, Ruogu Kang
During the process of microwave heating, when the microwave is radiated from free space to the heating material, only part of the microwave is radiated into the material while another part is reflected, due to a mismatch between the characteristic impedance of free space and the input impedance of the material (the input impedance relates to the characteristic of the material and varies with different materials). The microwave radiated into the material will interact with it, and will be absorbed to be converted into other forms of energy (mainly thermal energy), whereas the unconsumed microwave will either continue to propagate through the material, or be reflected multiple times and then propagate to the surface of the material, where it will form the reflected waves. The microwave absorption of the material is mainly determined by two factors: (1) How much the microwave enters the material, which is the impedance matching characteristic; and (2) How much the microwave enters the material and is consumed, which is the attenuation characteristic (Fang et al. 2019).