scholarly journals Modeling Human Body Using Four-Pole Debye Model in Piecewise Linear Recursive Convolution FDTD Method for the SAR Calculation in the Case of Vehicular Antenna

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ammar Guellab ◽  
Qun Wu
Keyword(s):  
Experimental Data ◽  
Human Body ◽  
Piecewise Linear ◽  
Broad Band ◽  
Fdtd Method ◽  
Debye Model ◽  
Whole Body ◽  
Human Body Model ◽  
Body Tissues ◽  
Recursive Convolution

We propose an efficient finite difference time domain (FDTD) method based on the piecewise linear recursive convolution (PLRC) technique to evaluate the human body exposure to electromagnetic (EM) radiation. The source of radiation considered in this study is a high-power antenna, mounted on a military vehicle, covering a broad band of frequency (100 MHz–3 GHz). The simulation is carried out using a nonhomogeneous human body model which takes into consideration most of the internal body tissues. The human tissues are modeled by a four-pole Debye model which is derived from experimental data by using particle swarm optimization (PSO). The human exposure to EM radiation is evaluated by computing the local and whole-body average specific absorption rate (SAR) for each occupant. The higher in-tissue electric field intensity points are localized, and the SAR values are compared with the crew safety standard recommendations. The accuracy of the proposed PLRC-FDTD approach and the matching of the Debye model with the experimental data are verified in this study.

APPLICABILITY OF HOMOGENEOUS HUMAN TRUNK PHANTOM IN ESTIMATING THE RADIATION CHARACTERISTICS OF BODY-WORN DEVICES

2008 ◽  
Vol 05 (01) ◽  
pp. 65-82 ◽  
Author(s):  
LISHENG XU ◽  
MAX Q.-H. MENG ◽  
HONGLIANG REN
Keyword(s):  
Electric Fields ◽  
Human Body ◽  
Biological Effects ◽  
Fdtd Method ◽  
Communication Link ◽  
Human Body Model ◽  
Radiation Characteristics ◽  
Worst Case ◽  
Half Wavelength ◽  
Link Performance

In this paper, the radiation characteristics with respect to the suitability of using homogeneous phantom for testing the compliance of radiation frequency devices are assessed. The Finite-Difference Time-Domain (FDTD) method is applied to analyze the variations of a 900 MHz half-wavelength dipole antenna's biological effects and link performance depending on distance between antenna and human body model. The distance between the surface of the model and the outside exposure source is changed from 25 mm to 1 mm within the range of λ/2π. The distributions of the specific absorption rates (SARs) and the electric fields for various vertical slices of a simplified homogeneous phantom and three anatomical human body trunk models are calculated, respectively. The legs and head have little influence on the radiation characteristics of body-worn, ingestible or implantable wireless devices. The results demonstrate that a homogenous representation of human body is suited for assessing the averaged SARs in human body and confirm that the local energy absorption details and communication link performance need to be analyzed by using the anatomical models or by combining with the worst-case consideration.

scholarly journals Practical Solution for Effective Whole-Body Magnetic Fluid Hyperthermia Treatment

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Hiroaki Mamiya ◽  
Yoshihiko Takeda ◽  
Takashi Naka ◽  
Naoki Kawazoe ◽  
Guoping Chen ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Magnetic Fluid ◽  
Human Body ◽  
Short Pulse ◽  
Alternative Methods ◽  
Whole Body ◽  
Human Body Model ◽  
Hyperthermia Treatment ◽  
Shell Nanoparticles ◽  
Magnetic Fluid Hyperthermia

Magnetic fluid hyperthermia therapy is considered as a promising treatment for cancers including unidentifiable metastatic cancers that are scattered across the whole body. However, a recent study on heat transfer simulated on a human body model showed a serious side effect: occurrences of hot spots in normal tissues due to eddy current loss induced by variation in the irradiated magnetic field. The indicated allowable upper limit of field amplitude Hac for constant irradiation over the entire human body corresponded to approximately 100 Oe at a frequency f of 25 kHz. The limit corresponds to the value Hacf of 2.5 × 106 Oe·s−1 and is significantly lower than the conventionally accepted criteria of 6 × 107 Oe·s−1. The present study involved evaluating maximum performance of conventional magnetic fluid hyperthermia cancer therapy below the afore-mentioned limit, and this was followed by discussing alternative methods not bound by standard frameworks by considering steady heat flow from equilibrium responses of stable nanoparticles. Consequently, the clarified potentials of quasi-stable core-shell nanoparticles, dynamic alignment of easy axes, and short pulse irradiation indicate that the whole-body magnetic fluid hyperthermia treatment is still a possible candidate for future cancer therapy.

scholarly journals Spine injury assessment under spaceflight landing conditions using multibody model

2018 ◽  
Vol 232 (4) ◽  
pp. 555-567
Author(s):  
AA Pasha Zanoosi ◽  
R Kalantarinejad ◽  
M Haghpanahi
Keyword(s):  
Finite Element ◽  
Human Body ◽  
Sagittal Plane ◽  
Rigid Bodies ◽  
Whole Body ◽  
Spine Injury ◽  
Human Body Model ◽  
Multibody Modeling ◽  
Multibody Model ◽  
Injury Assessment

The novelty of the study relies on the fact that current simulations of human body to assess spine injury are based on finite element method. Spine injury assessment is an important point in designing spacecraft seat especially during landing. The finite element-based human body simulations are very time-consuming and computationally expensive. These problems make it difficult to perform high computational simulations such as optimization, sensitivity analysis, and so forth. Hence, in this study, it is tried to resolve these problems by developing a multibody model of human body in landing phase of spacecraft. This model makes designers able to perform corresponding simulations faster with acceptable accuracy. This study presents a dynamic multibody model of spacecraft seat-occupant system for spine injury assessment under landing conditions. The landing situation of spacecraft exposes shock loads to the spacecraft and astronaut. Hence, spine injury assessment under landing conditions enables optimal injury design of seat-occupant system. The modeling method is based on using the multibody modeling to achieve a detailed description containing the nonlinear properties and the accuracy of a multibody dynamic model considering whole body comprising stretching of vertebrae. The human body model comprises head, spine, femur, and shank lying on a flexible polyurethane foam as seat cushion. To model the spine, viscera, and pelvis in the sagittal plane, the spine column considered to be rigid bodies accompanied by spring-damper elements. To validate the developed model, the modal analysis and seat-to-head transmissibility of the spine has been validated by comparing with previously published models. Finally, as an application, the developed model has been exposed to a landing shock load for spine injury assessment.

Sign in / Sign up

Export Citation Format

Share Document