Human Body Radiation Research Articles

Thermal Management in Nanofiber-Based Face Mask.

Face masks are widely used to filter airborne pollutants, especially when particulate matter (PM) pollution has become a serious concern to public health. Here, the concept of thermal management is introduced into face masks for the first time to enhance the thermal comfort of the user. A system of nanofiber on nanoporous polyethylene (fiber/nanoPE) is developed where the nanofibers with strong PM adhesion ensure high PM capture efficiency (99.6% for PM2.5) with low pressure drop and the nanoPE substrate with high-infrared (IR) transparency (92.1%, weighted based on human body radiation) results in effective radiative cooling. We further demonstrate that by coating nanoPE with a layer of Ag, the fiber/Ag/nanoPE mask shows a high IR reflectance (87.0%) and can be used for warming purposes. These multifunctional face mask designs can be explored for both outdoor and indoor applications to protect people from PM pollutants and simultaneously achieve personal thermal comfort.

Equivalent Permittivity Based on Debye Model of Blood and Its SAR

Dielectric parameters vary with frequencies are important properties of biological systems, which determine the absorption rates of electromagnetic radiation in human body. Two phase dielectric model is considered to investigate the dielectric properties of human blood in this paper. This paper systematically calculates the body's specific absorption rate of electromagnetic fields at low frequencies based on the dielectric properties obtained from the Debye model. This study could lay foundation not only for the theoretical basis for further study on electrical properties of biological tissue, but also for the exposure limits of health standard on electromagnetic radiation.

被动式红外感应自动水龙头的设计

本文介绍一种被动红外感应式水龙头，利用人体产生的红外辐射作为信号源，选用红外光子型探测器掺杂锗来探测，可以高效响应人体辐射的峰值波长，并且响应快，受环境温度影响小。在详细分析人体辐射特性的基础上，选择合适的红外探测器和相应的信号处理电路，设计了被动式红外感应自动水龙头系统，用指示灯代替水龙头，并验证了设计方案的正确性。 The article introduces a kind of passive infrared induction faucet, that is infrared radiation generated by the human body as a signal source, chooses the infrared photon detector doping germanium to detect, which can efficient response to the peak wavelength of radiation human body, and response rapidly, free from interference environmental temperature. On the basis of detailed analysis of the human body radiation characteristics and selecting the appropriate infrared detector, the design of passive infrared induction automatic faucet was built, with the corresponding signal processing circuit, using indicator light instead of faucet, validated the correctness of design scheme.

Radiative human body cooling by nanoporous polyethylene textile.

Thermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving. We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers). We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton. Our processed nanoPE is an effective and scalable textile for personal thermal management.

A human body positioning system with pyroelectric infrared sensor

This paper aims to improve the accuracy of pyroelectric infrared sensor-based human body positioning system by studying the characteristics of the human body radiation signal. We designed the amplifying and filtering circuits to capture the signals. We also built a human body positioning system. Considering the impact of external interference, the body velocity, the distance between sensors and human target, we propose a new algorithm for the system to interpret the target information in the sensing area considering several impacts. Besides, in the system, the sensing area was divided into smaller grids to make human positioning more accurate. We evaluate the proposed algorithm based on real test-bed and we repeated the experiments for 480 times and validated that the proposed human positioning system can track people with the tracking error for only 0.46 m.

Research of Water Response under the Action of the Infrared Human Body Radiation by Water Conductometric Sensors

Non-equilibrium thermal and biothermal radiation generated by heated solid materials and hematothermal living organisms are studied by water conductometric sensors. Engineering aspects and physical features of developed water conductometric sensors are given. Procedure and measuring technique are described. Our experiments show the anomalous behavior of water conductivity and associated differential parameters under water heating by biological objects compared with traditional heating sources. Water response to human action strongly depends on psychophysiological and psychoemotional state of the person. Moreover the responses to the action by left and right human hands are substantially different and as a rule are specific to the gender. The possible physicochemical mechanisms of such anomalous water behavior are studied. It is suggested that the observed effects are associated with resonant excitation of vibration-rotation energy levels of water under the influence of bioradiation generated by human organism consisting of approximately 70% water. The results obtained have good perspectives for future applications in different fields of human activity.

A Novel Folded UWB Antenna for Wireless Body Area Network

A novel folded ultrawideband antenna for Wireless Body Area Network (WBAN) is proposed, which can effectively reduce the backward radiation and proximity effects of human bodies. The proposed antenna has a low-profile 3D structure that consists of a bevel-edge feed structure and a metal plate with folded strip. The bevel edge feed structure achieves broadband impedance matching and the metal plate acts as the main radiator. Moreover, the folded strip not only extends the lower frequency band but also provides additional resonant frequency around 6 GHz. The final bandwidth covers from 3.1 GHz to 12 GHz. The proposed antenna shows the directional patterns with low backward radiation due to the patch-like structure and the ground plane also prevents from the proximity effects of human bodies. Furthermore, the simulated SAR values of the proposed antenna are lower than the values of omnidirectional disc planar monopole. These features demonstrate that the proposed antenna is suitable for WBAN application.

Thermal Microwave Radiation for Subsurface Absolute Temperature Measurement

Problems related to thermal radiation of human bodies in the microwave range are presented in the paper from medical diagnosis point of view. The paper reviews physical principles of thermal radiation measurement at microwave frequencies. A design of a modulation type radiometer with both zero reading and compensation of influence of the reflectivity is presented in the paper. On the base of this design, requirements for absolute temperature measurement conditions in the lossy and homogeneous medium were found. It is worth noting that these demands do not need any limitations for environmental parameters, especially for their stability during measurement (ambient temperature stability). At the end, experimental results of the measurements carried out with the use of the microwave radiometer operating in the 1.5 GHz band are shown.

Exploration of Whole Human Body and UWB Radiation Interaction by Efficient and Accurate Two-Debye-Pole Tissue Models

We have developed a computationally efficient finite-difference time-domain (FDTD) model of a whole human body based on accurate 2-pole Debye dispersion dielectric tissue properties. Comprehensive FDTD analyses of the interaction between a whole human body and ultrawideband (UWB) radiation are carried out by including the proposed frequency dependent tissue models. The 2-pole Debye models have been obtained for 50 individual human tissues from Gabriel's Cole-Cole data by the least squares fitting technique over the frequency range from 100 MHz to 6 GHz. A whole human body composed of the 2-pole Debye models is exposed to spread spectrum radiation. Local energy absorption in a human body is compared between the proposed model and the conventional model of frequency-independent permittivity and conductivity. Resonance states are then investigated in the human body exposed to electromagnetic nano-second pulse radiation. For the extraction of the frequency contents from the highly damped FDTD time signals, a spectrum analysis technique based on an auto-regressive (AR) model has been applied. Pulse propagation in the vicinity of the human body is also characterized by the proposed model for the wireless body area network (WBAN) application that has been proposed recently for computer assisted medical diagnostics and rehabilitation.

Fully printed, flexible, large area organic optothermal sensors for human-machine-interfaces

Pyroelectric sensors presented in this work are based on polymers from the PVDF family which are comprised of a piezo- and/or pyroelectric polymer thin film capacitor integrated with either high performance organic thin film transistors (OTFTs) or electrochemical transistors (ECTs) acting as impedance converters, signal amplifiers and conditioners.For flexible integration with diverse electronic devices, large area processes such as screen printing applicable for industrial partners have been used for the fabrication of the sensors and ECT’s. With respect to the intended purpose for detection of human body radiation the absorbance of the impinging IR-light is dramatically increased by the application of printed carbon/Pedot topelectrodes, hence meeting the requirements for low-cost large area processibility.Here we present good working integrated sensor devices based on two components, being an organic thin film transitor with a high-k-nanocomposite gate dielectric or a fully printed electrochemical transistor and a PVDF-copolymer based sensor.

Miniaturized InSb photovoltaic infrared sensor operating at room temperature

This paper reports the development of a novel InSb infrared photovoltaic sensor (PVS) operating at room temperature. The PVS consists of an InSb p+p−n+ structure grown on semi-insulating GaAs(100) substrate, with a p+-Al0.17In0.83Sb barrier layer between the p+ and p− layers to reduce diffusion of photoexcited electrons. Photodiodes were fabricated by wet etching, and, using a 500-K blackbody, we obtained detectivity D*=2.8×108 cm Hz1/2/W and responsivity RV=1.9 kV/W at room temperature. The SNR was improved with the serial connection of 700 photodiodes patterned on a 600×600-µm2 chip. On increasing the number N of connected photodiodes, the SNR was improved by a factor of N1/2. The responsivity was constant for signals ranging from dc to 500 Hz. From spectral response measurements a cutoff wavelength of 6.8 µm was obtained. The PVS was flip-chip bonded on pre-amplifier IC, allowing the shortest possible connection between the PVS and the pre-amplifier, making the system immune to electromagnetic noise. The system was finally encapsulated in a dual flat nonleaded package with a window, which exposes the back of the GaAs substrate, allowing the infrared light incidence. The device is small (2.2×2.7×0.7 mm3), operates at room temperature, and is able to detect human body radiation in the middle IR range.

Effective 2-Debye-Pole FDTD Model of Electromagnetic Interaction Between Whole Human Body and UWB Radiation

We have successfully developed a human body finite difference time domain model based on efficient two-pole Debye dispersion, and analyzed for the first time the electromagnetic interaction between a whole human body and ultra wide band radiation having a wide frequency spectrum. The two-pole Debye dispersion model is obtained for 50 individual human tissue properties from Gabriel's Cole-Cole data by least squares fitting over a wide frequency range from 100 MHz to 6 GHz. For validation, the model is exposed to radiation of a spread spectrum signal modulated by typical binary phase shift keying. Local energy absorption in a human body has been compared between the two-pole Debye model and a conventional model with frequency-independent permittivity and conductivity.

Evaluating human body area factors from digital images: A measurement tool for a better evaluation of the ergonomics of working places

The evaluation of comfort conditions of people in confined environments requires a knowledge of the human body's radiation data. This is essentially represented by the projected area of the body in a given direction. From this factor, other important parameters can be computed, such as projected area factors and angle factors. Presently, these parameters are evaluated using graphs deriving from a pioneering field study carried out by P.O. Fanger for which a piece of apparatus using mirrors and weight operations on film negatives is used. Obviously, these graphs, apart from referring to a limited number of subjects, also involve some reading errors. With the aim of enlarging the number of experimental cases and in order to provide a simplified method of making measurements, this work proposes a new experimental procedure based on digital images of the human body which are processed using a computer-based system. The first part of the paper is dedicated to the description of this procedure and to some early comparison with data found in the literature on the subject. The second part concerns the introduction of a new method for computing the effective area of people, starting from the projected areas taken by means of the present apparatus.

Check of the Application of the Monte Carlo Method for Spectrometry of Human Body Radiation in an Experiment on Large Animals

This paper is devoted to an experimental check of a method for performing individual calibration of a spectrometer for human body radiation, using the Monte Carlo method, on 35–40 kg pigs. The 241Am content was measured on a low-energy γ spectrometer with a detector based on highly pure germanium. Tomographic images of pigs were used to calculate, using the MCNP4c2 program, the spectra of absorbed energy in a detector. The experimental results are reproduced with an error of less than 30% for injection of 241Am and less than 10% for 241Am introduced in a capsule.

Modern internal-irradiation dosimetry

A graphical user interface making it possible to create initial data files automatically for calculating the radiation spectrum of a human body using the MCNP™ program and to perform graphical analyis of the computational results is described. The results of using the program developed to perform spectrometry of human-body radiation and internal dosimetry are desrcribed. The development of precise measurement methods, such as the spectrometry of human-body radiation, and the appearance of new methods for analyzing the results of measurements will make the monitoring of internal irradiation of workers in the nuclear power industry more accurate.

Multifrequency microwave thermograph for biomedical applications

This paper presents problems related to thermal radiation of human bodies in microwave range in aspect of diagnosis of breast carcinoma. A mathematical model of thermal radiation transfer through tissues is introduced and methods of measurement of temperature, depth and size of a heat source, by means of multifrequency microwave thermography are described. Theoretical considerations are supplemented by presentation of experimental results.

Optical systems for security engineering

An overview of the main optical methods used today in the detection of fire is presented, including optical smoke detection by light scattering and obscuration, as well as infrared flame detection. Further, intrusion detection by detection of emitted infrared radiation of human bodies is discussed.