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Electrophysiology
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
In the physiological system, the ions act as charge carriers and whose movement provide the key mechanism for electric conductivity in the human body (Albulbul, 2016; Enderle & Bronzino, 2012). Consequently, the electrodes and the measurement system are required to collect the electrical signals from the localized parts of the human body. The electrical signals from the body are measured using electrodes which are made up of electrical conductors and conducting fluids. The interaction between the ions in the body and electrons in electrodes can significantly affect sensor performance. These reactions can be described for movement of charge in between the electrons and ions using the Equations 3.8 and 3.9 (Bronzino, 2000; Enderle & Bronzino, 2012):
Acceleration
Published in Rob Appleby, Graeme Burt, James Clarke, Hywel Owen, The Science and Technology of Particle Accelerators, 2020
Rob Appleby, Graeme Burt, James Clarke, Hywel Owen
where μ is the permeability of the conductor (where for most RF materials ) and σ is the electrical conductivity of the conductor. As there is an electric field inside the conductor a current is induced in it, given by Ohm's law , where J is the current density. This in turn leads to a power loss as the current is being driven through a resistance. This surface resistance, Rsurf, is given by
Stimulus-Receptive Conductive Polymers for Tissue Engineering
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Hence, for essential mechanisms, doping is the key element for the conductive polymer. Doping is also recognized as a charge transfer reaction, which creates active sites (polarons) of the polymer, removing an electron from the valence band (p-doping) or adding an electron to the conduction band (n-doping) through redox reaction to enable the carriers (electron and holes) to move from one site to another (Zhou et al. 2010, Ghasemi-Mobarakeh et al. 2009, Bredas and Street 1985). Where an electron is missing, it is regarded as a hole. A new hole is created and allows the charge to migrate over a long distance when such a hole is filled by a jumping in electron from the neighboring position. This movement of charge is responsible for electrical conductivity. Simply, the doping process generates charge carriers producing a number of mobile carriers in a polymer to contribute to the conductivity. The charge carrier, in the form of extra electrons or “holes”, should be injected into the material, which is also known as ‘dopant’ (Pelto et al. 2010). Conductivity increases very rapidly as dopant is added.
Recent research advances on simulation modeling of temperature distribution in microwave ablation of lung tumors
Published in Computer Assisted Surgery, 2023
Ju Liu, Hongjian Gao, Jinying Wang, Yuezheng He, Xinyi Lu, Zhigang Cheng, Shuicai Wu
The tissue electrical properties (electrical conductivity/21]. The precise characterization of tissue parameters is conducive to improve the simulation accuracy. Many researchers have previously demonstrated the impact of uncertainty in tissue properties and their temperature dependency on MWA model outcomes. They have also carried out in-depth exploration on the parameters setting of the lung tissue. Furthermore, the effect of respiratory movement on tissue characteristics is also taken into account to increase the accuracy of simulation results.
Validation and practical use of Plan2Heat hyperthermia treatment planning for capacitive heating
Published in International Journal of Hyperthermia, 2022
Because of the low frequency applied for capacitive heating, power distributions were calculated by solving the quasi-static formulation of Maxwell’s equations, enabling much faster simulations compared to solving the full Maxwell’s equations using the Finite Difference Time Domain method. The metal electrodes at the top and bottom were kept at a constant potential of 1 V and −1 V, respectively. The boundaries of the simulation domain were fixed at zero potential. The electric field vector can be written as V [20]. Plan2Heat uses CUDA GPU accelerated calculations. The power density (PD) is then calculated using: m−1) the electrical conductivity. For SAR evaluation 1 cc averaged values were considered. Dielectric and thermal tissue properties used in the phantom and patient simulations were based on literature and are listed in Table 1.
Multi-parametric groundwater quality and human health risk assessment vis-à-vis hydrogeochemical process in an Agri-intensive region of Indus basin, Punjab, India
Published in Toxin Reviews, 2022
Vijay Jaswal, Ravishankar Kumar, Prafulla Kumar Sahoo, Sunil Mittal, Ajay Kumar, Sunil Kumar Sahoo, Yogalakshmi Kadapakkam Nandabalan
All groundwater samples were odorless, colorless and showed no specific taste. The statistical summary of physico-chemical characterization of groundwater samples collected from the study area are compared with drinking water standards (BIS 2012) and summarized in Table 2. From the table, it is evident that the groundwater samples were alkaline as the pH ranged from 6.41–8.07 with a mean value of 7.23. pH is influenced by carbonate, bicarbonate and carbon dioxide equilibrium (Hem 1985 Huang et al. 2013). The presence of various salts in water samples is depicted as electrical conductivity (EC), and it was observed to range from 460 − 4740 µS cm−1 (mean 1743 µS cm−1). The TDS varied significantly from 308 to 3145 mg L−1 (mean value of 1168 mg L−1) with 96% of groundwater samples exceeding the acceptable limit of 500 mg L−1 (BIS 2012) as evidenced from the TDS distribution maps (Figure 2).