Ban Rangsit, Thailand

Eastern Asia University

www.eau.ac.th
Ban Rangsit, Thailand

Time filter

Source Type

Wessapan T.,Eastern Asia University | Srisawatdhisukul S.,Rangsit University | Rattanadecho P.,Rangsit University
International Journal of Heat and Mass Transfer | Year: 2012

This study presents a numerical analysis of specific absorption rate (SAR) and temperature distributions in the realistic human head model exposed to mobile phone radiation at 900 MHz and 1800 MHz. In the realistic human head model, the effects of operating frequency and gap distance between the mobile phone and the human head on distributions of specific absorption rate and temperature profile within the human head are systematically investigated. This study focuses attention on each tissue in the human head in order to investigate the effects of mobile phone radiation on the human head. The SAR and the temperature distribution in various tissues in human head during exposed to mobile phone radiation, obtained by numerical solution of electromagnetic wave propagation and unsteady bioheat transfer equations, are presented. For both frequencies, the highest SAR values are obtained in the region of the skin near the antenna. It is found that the highest SAR values are 0.823 W/kg and 1.187 W/kg for the frequencies of 900 MHz and 1800 MHz, respectively. The SAR values obtained from this study are well below ICNIRP limit for all cases. In addition, it is found that the temperature distributions are not directly proportional to the local SAR values. Moreover, the experimental validation has been carried out by using the infrared camera in order to complement the simulation results. © 2011 Elsevier Ltd. All rights reserved.


Wessapan T.,Eastern Asia University | Rattanadecho P.,Rangsit University | Wongchadakul P.,Rangsit University
Numerical Heat Transfer; Part A: Applications | Year: 2016

Heating is the main biological effect of the electromagnetic (EM) fields to human eye. This study intends to focus attention on the differences in the heat transfer characteristics of the human eye induced by EM fields in different body positions. The effect of three different body positions – sitting, supine, and prone – on natural convection of aqueous humor (AH) in the anterior chamber of the eye is systematically investigated. The specific absorption rate (SAR) value, fluid flow, and the temperature distribution in the eye during exposure to EM fields are obtained by numerical simulation of EM wave propagation. In this study, the frequencies of 900 and 1,800 MHz are chosen for the investigations. The heat transfer model used in this study is developed based on natural convection and porous media theories. The results show that the AH temperature inside the anterior chamber is the highest in the supine position at both frequencies. It is found that during exposure to EM fields, body position plays an important role on AH natural convection and the heat transfer process within the anterior chamber and its periphery in the front part of the eye. However, the body position has no significant effect on temperature distribution for the middle part of the eye. The obtained results provide information on the body position and thermal effects from EM fields exposure. 2016 Copyright © Taylor & Francis Group, LLC


Wessapan T.,Eastern Asia University | Rattanadecho P.,Rangsit University
International Journal of Heat and Mass Transfer | Year: 2013

This study presents a numerical analysis of the specific absorption rate (SAR) and the heat transfer in a heterogeneous human eye model exposed to electromagnetic (EM) fields of 900 and 1800 MHz. In this study, the effect of operating frequency on the SAR and temperature distributions in the eye was systematically investigated. The SAR value and the temperature distribution in various tissues in the eye during exposure to EM fields were obtained by numerical simulation of EM wave propagation and a heat transfer model was then developed based on the natural convection and porous media theories. The study highlights two transport phenomena: heat and mass transfer in the eye during exposure to EM fields at different frequencies. This study indicated that when the eye exposed to EM fields at the frequencies of 900 and 1800 MHz, the highest SAR values at two chosen frequencies was in the cornea, and the highest temperature at the frequency of 900 MHz was in the anterior chamber while the highest for the frequency of 1800 MHz was in the vitreous. The temperature distribution in the eye induced by EM fields was not directly related to the SAR distribution due to the effect of the interaction among the dielectric properties, thermal properties, blood perfusion, and penetration depth of the EM power. Moreover, this study also showed that the exposure time had an influence on the temperature increase in the eye. © 2013 Elsevier Ltd. All rights reserved.


Wessapan T.,Eastern Asia University | Rattanadecho P.,Thammasat University
International Journal of Heat and Mass Transfer | Year: 2014

The topic of temperature increase in human tissue when exposed to EM fields, particularly those radiated to the eye, has been of interest for many years. This study presents a numerical analysis of the specific absorption rate (SAR) and the heat transfer in a heterogeneous two-dimensional human eye model exposed to TM-mode of electromagnetic (EM) fields of 900 MHz at various power densities. In this study, the effects of ambient temperature and power density on the temperature distributions and fluid flow in the eye during exposure to electromagnetic fields were systematically investigated. The electric field, SAR, temperature distribution and fluid flow in various tissues in the eye during exposure to EM fields were obtained by numerical simulation of EM wave propagation and a heat transfer model. The heat transfer model was then developed based on the porous media theories. The study highlights heat transfer and fluid flow in the eye during exposure to EM fields at different ambient temperatures. This study indicated that when the eye exposed to EM fields at the frequency of 900 MHz, the highest electric field intensity and SAR values at the chosen frequency was in the cornea. At the highest power density of 100 mW/cm2, the absorbed EM energy is converted to heat causes a further increase of 3 C in corneal temperature in cases of hot, moderate and cold ambient temperatures. The result shows important information related to a complex interaction between ambient temperature, fluid flow and temperature distribution in the eye during exposure to electromagnetic fields. Moreover, this study also showed that the power density had a strong influence on the temperature increase and fluid flow in the eye. © 2013 Elsevier Ltd. All rights reserved.


Wessapan T.,Eastern Asia University | Rattanadecho P.,Thammasat University
Numerical Heat Transfer; Part A: Applications | Year: 2015

Among the reported health benefits of a sauna session are weight loss, detoxification of the body, and improved blood circulation. Side effects of sauna therapy, both beneficial and detrimental, also exist. It is well known that the human eye is one of the most sensitive parts of the entire human body when exposed to high ambient temperature and humidity levels such as in sauna therapy. This sauna heat interacts with the human eye and may lead to a variety of ocular effects due to radiation emitted by the heater and high ambient temperature. However, the resulting thermophysiologic response of the human eye to various exposure conditions during sauna therapy is not well understood. Therefore, it is of interest to investigate the potential ocular effects that may occur during sauna exposure. This study presents a numerical analysis of heat transfer in a heterogeneous model of a human eye exposed to sauna. The heat transfer model is developed based on porous media theories. In the heterogeneous human eye model, the effects of room air temperature and heater temperature on the intraocular temperature increase are systematically investigated. The study intends to focus attention on the different heat transfer characteristics between conventional sauna (mainly convection) and infrared sauna (mainly radiation). The results show that at the same room air temperature, the circulatory patterns within the anterior chamber of the eye in regard to infrared sauna are more rapid than those for the conventional sauna. Moreover, eye temperature is also higher in the infrared sauna than in the conventional sauna. The maximum temperatures of the eye exposed to conventional and infrared saunas at room air temperature of 80°C are 48.25°C and 52.90°C, respectively. From the values obtained, a guideline can be recommended to indicate the limitations in regard to temperature increase in the human eye due to sauna therapy. © 2015 Taylor and Francis Group, LLC.


Klongpityapong P.,Eastern Asia University | Supabphol R.,Srinakharinwirot University | Supabphol A.,Srinakharinwirot University
Asian Pacific Journal of Cancer Prevention | Year: 2013

Background: To assess the antioxidant effects of gamma-oryzanol on human prostate cancer cells. Materials and Methods: Cytotoxic activity of gamma-oryzanol on human DU145 and PC3 prostate cancer cells was determined by proliferation assay using 3-(4, 5-dimethylthiazol, 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) reagent. mRNA levels of genes involved in the intracellular antioxidant system, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GSR) were determined by reverse transcription-polymerase chain reaction (RT-PCR). Cancer cell lysates were used to measure lipid peroxidation using thiobarbituric acid reactive substance (TBARS). Glutathione contents of the cell lysates were estimated by the reaction between sulfhydryl group of 5, 5'-dithio (bis) nitrobenzoic acid (DTNB) to produce a yellow-color of 5-thio-2-nitrobenzoic acid using colorimetric assay. Catalase activity was also analysed by examining peroxidative function. Protein concentration was estimated by Bradford's assay. Results: All concentrations of gamma-oryzanol, 0.1-2.0mg/ml, significantly inhibited cell growth in a dose- and time-dependent fashion in both prostate cancer cell lines, DU145 and PC3. Gene expression of catalase in DU145 and PC3 exposed to gamma-orizanol at 0.5mg/ml for 14 days was down regulated, while mRNA of GPX was also down regulated in PC3. The MDA and glutathione levels including catalase activity in the cell lysates of DU145 and PC3 treated with gamma-oryzanol 0.1 and 0.5mg/ml were generally decreased. Conclusions: This study highlighted effects of gamma-oryzanol via the down-regulation of antioxidant genes, catalase and GPX, not cytotoxic roles. This might be interesting for adjuvant chemotherapy to make prostate cancer cells more sensitive to free radicals. It might be useful for the reduction of cytotoxic agents and cancer chemoprevention.


Uyaisom C.,Eastern Asia University
Procedia Engineering | Year: 2011

This paper presents the effect of jumbo compact fluorescent lamp (energy saving lamp) on the electrical energy saving and harmonics noise. The test was set to find public favor in marketto test. The power rate of incandescent lamp are 200 watts, ML are 160 watts and 250 watts and compact fluorescent lamps (energy saving lamps type) are 23 watts, 24 watts (small size), 45 watts,65 watts and 85 watts (jumbo size). The effect of the lamps on the illuminance efficiency, electrical performance and harmonics noise are compared to verify the effectiveness of each lamps.


Kaewanuchit C.,Eastern Asia University
Procedia Engineering | Year: 2011

This paper presents a small-signal model of the series-parallel resonant DC-DC converter with capacitive output filter. This model is based on generalized averaging method. It simplifies the controller design task for resonant converter. Simulations are used to verify the accuracy of the small-signal model.


Uyaisom C.,Eastern Asia University
Advanced Science Letters | Year: 2014

Personal computer or PC is widely used in business, industry, education, and entertainment. Today, a PC can be either a desktop PC or an all-in-one PC. All-in-one PCs are newer models that are increasingly more popular because they are small, and so need less space, are easy to move, and consume less electrical energy, up to 77.36%. However, an All-in-one PC may cause a serious problem of power quality, such as harmonics noise and low power factor, to control systems. Particularly, it can affect other electronic devices connected to the same main and cause electronic malfunction or even permanently damage these devices. © 2014 American Scientific Publishers All rights reserved.


Kerdlap P.,Eastern Asia University
Applied Mechanics and Materials | Year: 2014

This paper presents the effect of power supply of LED lamp for external lighting are compares with electrical performance, electrical energy saving, illuminance, and the effect of harmonics noise from each power supplies on external lighting with LED. By designing and construct a linear power supply by the full wave rectifier circuit by bridge diode type and switching power supply by buck converter. The result that, the full wave rectifier circuit by bridge diode type was consumed higher power less than buck converter but lower effect of harmonics noise. In additional, as a result will be important data to the education develops and the next research. © (2014) Trans Tech Publications, Switzerland.

Loading Eastern Asia University collaborators
Loading Eastern Asia University collaborators