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Fulltext Harnessing energy from electromagnetic field: practical implementation integrating coil antenna and IC load

Syahrizal Salleh, Zulkifli Abd Majid

Pertanika Journal of Science & Technology, 2013;21(2):555-566.
MyJurnal

An AC to DC voltage rectifier and its respective regulator were designed and integrated on a 0.25μm CMOS process. Its input impedance was measured along with the regulated DC output. Input impedance of a series of rectangular coil microstrip antenna on FR4 PCB with outer dimension of 78mm x 41mm was measured. The positive reactance of the antenna was matched at resonance with negative reactance of the integrated rectifier and regulator with addition of external capacitor. Relationship between incidental electromagnetic field in A/m at the coil microstrip antenna all the way to the rectified DC voltage at the output of the regulator is presented. In the context of wireless power transfer, this work focuses on the remote unit that absorbs electromagnetic field generated by another system and converts the energy into DC supply voltage for remote device

Matched MeSH terms: Electromagnetic Fields
Fulltext Measurement and Mapping of Wi-Fi Radiation Level at Hamdan Tahir Library, Universiti Sains Malaysia Health Campus

Supardi, N. F., Mohd Taib, N. H., Abu Amat, N. H., Yusoff, M. N. S.

Physics and Technology in Medicine, 2020;1(1):52-57.
MyJurnal

Wi-Fi is a wireless communication technology that uses specific electromagnetic frequencies. The increasing use of Wi-Fi has raised public concerns about the impact of electromagnetic radiation on the environment and human health. Since the exposure level of the electromagnetic field (EMF) radiation differs between different locations, it is important to measure the strength of the EMF at various locations under observation. This study aimed to obtain specific values related to the radiofrequency and microwave EMF which is described by four specific parameters, that are 1) the frequency of the wave, 2) the electric field strength E, 3) the magnetic field strength H, and 4) the power density S. This study was carried out at the first floor area of Hamdan Tahir Library, Universiti Sains Malaysia Health Campus. Mapping of Wi-Fi signal and measurement of Wi-Fi radiation level was performed at four specific locations, that are Laptop zone 1, Laptop zone 2, Computer lab, and Cozy corner. The average radiation level was compared with the ICNIRP standard limit for public user. It was observed that the Wi-Fi signal was highest in Laptop zone 2 followed by Laptop zone 1 which displayed a moderate signal strength. Whereas moderate but lower signal level was detected in Computer lab zone and Cozy corner. The electric and magnetic fields as well as power density were found highest in Laptop zone 1, followed by Laptop zone 2, Cozy corner, and Computer lab. Comparison with standard ICNIRP limit showed that the radiation level is still far below the ICNIRP limit, which is only 2% of exposure level. To conclude, Laptop zone 2 exhibited the strongest Wi-Fi signal whereas Laptop zone 1 displayed the highest radiation level. However, the strength of the electric and magnetic fields as well as power density is still far below the ICNIRP limit.

Matched MeSH terms: Electromagnetic Fields
Fulltext Measurement and Mapping of Wi-Fi Radiation Level at Students Hostel in Universiti Sains Malaysia Health Campus

Abu Amat, N. H., Mohd Taib, N. H., Supardi, N. F., Yusoff, M. N. S.

Physics and Technology in Medicine, 2020;1(1):38-44.
MyJurnal

The increasing use of wireless communication devices, particularly Wi-Fi has raised public concerns on the exposure to electromagnetic field (EMF) and its possible effect on human health. As the exposure level of the EMF radiation varies between different locations, measurement of the EMF strength at various locations is vital. In this study, we aimed to measure the EMF exposure which is described by four specific parameters, specifically 1) the frequency of the wave, 2) the electric field strength E, 3) the magnetic field strength H, and 4) the power density S. This study was performed at the second floor in Nurani hostel block in Desasiswa Murni Nurani, Universiti Sains Malaysia Health Campus. Mapping of Wi-Fi signal and measurement of Wi-Fi radiation level was performed at four specific locations, that are in a student room, television room, prayer room, and ironing room. The average radiation level was compared with the standard limit set by International Commission on Non-Ionizing Radiation Protection (ICNIRP). It was observed that the strength of Wi-Fi signal was highest in students’ room followed by television room. Both of these rooms exhibited high signal strength. While moderate but lower signal level was observed in prayer room followed by ironing room. The electromagnetic field and power density were found highest in students’ room, followed by television room, prayer room, and ironing room. Comparison with standard ICNIRP limit showed that the radiation level is still far below the acceptable limit, which is only 2% of the exposure level. To conclude, students’ room exhibited the strongest Wi-Fi signal and the highest radiation level. However, the radiation level especially power density is still far below the ICNIRP limit.

Matched MeSH terms: Electromagnetic Fields
The effects of metamaterial on electromagnetic fields absorption characteristics of human eye tissues

Gasmelseed A, Yunus J

Prog Biophys Mol Biol, 2014 Jan;114(1):8-12.
PMID: 24239501 DOI: 10.1016/j.pbiomolbio.2013.10.004

The interaction of a dipole antenna with a human eye model in the presence of a metamaterial is investigated in this paper. The finite difference time domain (FDTD) method with convolutional perfectly matched layer (CPML) formulation have been used. A three-dimensional anatomical model of the human eye with resolution of 1.25 mm × 1.25 mm × 1.25 mm was used in this study. The dipole antenna was driven by modulated Gaussian pulse and the numerical study is performed with dipole operating at 900 MHz. The analysis has been done by varying the size and value of electric permittivity of the metamaterial. By normalizing the peak SAR (1 g and 10 g) to 1 W for all examined cases, we observed how the SAR values are not affected by the different permittivity values with the size of the metamaterial kept fixed.

Matched MeSH terms: Electromagnetic Fields*
Fulltext Combination effect of argan oil and low frequency electromagnetic field on open wound in mice

Siti F. Masre, Muzamir, M.K, Sabarina, I., Jehan, N., Yanti Rosli

Jurnal Sains Kesihatan Malaysia, 2018;16(101):41-45.
MyJurnal

This study was conducted to evaluate the effect of argan oil with the exposure of low frequency electromagnetic field (EMF) on open wound healing in mice. Eighteen male mice (20-40 g) were divided into three groups: phosphate buffer saline (PBS) as negative control, solcoseryl gel as positive control, and argan oil with the exposure of low frequency EMF, 1.2 mT (treatment group). Full thickness wounds (4 mm diameter) were induced on the shaved dorsal of the mouse. All mice were sacrificed on day 12 after the final treatment. Macroscopic observation, wound contraction rate, histopathology analysis and total protein content were examined in this study. Results showed that wounds treated with argan oil and exposed to low frequency EMF has a significant increase in wound contraction rate (p < 0.05) and total protein content (p < 0.05). Moreover, histopathological analysis on the wound tissues displayed complete re-epithelization with thick and dense collagen fibers in the argan oil with low frequency EMF exposure treated group. In conclusion, topical treatment of argan oil with low frequency EMF exposure yield a better healing progress and showed the ability to accelerate wound healing

Matched MeSH terms: Electromagnetic Fields
Fulltext Effects of electromagnetic field (EMF) on histological changes and norepinephrine levels in the brains of adult male rats

Yap, Hui Cin, Asmah Hamid, Farah Wahida Ibrahim, Nor Fadilah Rajab, Yanti Rosli

Jurnal Sains Kesihatan Malaysia, 2016;14(1):55-61.
MyJurnal

The emergence of research about the biological effects of electromagnetic field (EMF) have growing concern among
researchers. The aim of this study was to investigate the effects on the brain of rats periodically exposed to 0.1 mT EMF.
Total 24 adult male Sprague Dawley rats were subdivided randomly to 4 groups: 2 control groups (C1 6 hours: 6 h/
day for 5 days; C2 20 hours: 20 h/day for 5 days) and 2 treatment groups which exposed to 0.1 mT EMF (T1 6 hours:
6 h/day for 5 days; T2 20 hours: 20 h/day for 5 days). A significant decrease in the pyramidal cell number was higher
as the exposure duration to EMF was extended (T1, p

Matched MeSH terms: Electromagnetic Fields
Fulltext Enhancement of mesenchymal stem cell chondrogenesis with short-term low intensity pulsed electromagnetic fields

Parate D, Franco-Obregón A, Fröhlich J, Beyer C, Abbas AA, Kamarul T, et al.

Sci Rep, 2017 08 25;7(1):9421.
PMID: 28842627 DOI: 10.1038/s41598-017-09892-w

Pulse electromagnetic fields (PEMFs) have been shown to recruit calcium-signaling cascades common to chondrogenesis. Here we document the effects of specified PEMF parameters over mesenchymal stem cells (MSC) chondrogenic differentiation. MSCs undergoing chondrogenesis are preferentially responsive to an electromagnetic efficacy window defined by field amplitude, duration and frequency of exposure. Contrary to conventional practice of administering prolonged and repetitive exposures to PEMFs, optimal chondrogenic outcome is achieved in response to brief (10 minutes), low intensity (2 mT) exposure to 6 ms bursts of magnetic pulses, at 15 Hz, administered only once at the onset of chondrogenic induction. By contrast, repeated exposures diminished chondrogenic outcome and could be attributed to calcium entry after the initial induction. Transient receptor potential (TRP) channels appear to mediate these aspects of PEMF stimulation, serving as a conduit for extracellular calcium. Preventing calcium entry during the repeated PEMF exposure with the co-administration of EGTA or TRP channel antagonists precluded the inhibition of differentiation. This study highlights the intricacies of calcium homeostasis during early chondrogenesis and the constraints that are placed on PEMF-based therapeutic strategies aimed at promoting MSC chondrogenesis. The demonstrated efficacy of our optimized PEMF regimens has clear clinical implications for future regenerative strategies for cartilage.

Matched MeSH terms: Electromagnetic Fields*
Radio frequency electromagnetic radiation (RF-EMR) from GSM (0.9/1.8GHz) mobile phones induces oxidative stress and reduces sperm motility in rats

Mailankot M, Kunnath AP, Jayalekshmi H, Koduru B, Valsalan R

Clinics (Sao Paulo), 2009;64(6):561-5.
PMID: 19578660

INTRODUCTION: Mobile phones have become indispensable in the daily lives of men and women around the globe. As cell phone use has become more widespread, concerns have mounted regarding the potentially harmful effects of RF-EMR from these devices.
OBJECTIVE: The present study was designed to evaluate the effects of RF-EMR from mobile phones on free radical metabolism and sperm quality.
MATERIALS AND METHODS: Male albino Wistar rats (10-12 weeks old) were exposed to RF-EMR from an active GSM (0.9/1.8 GHz) mobile phone for 1 hour continuously per day for 28 days. Controls were exposed to a mobile phone without a battery for the same period. The phone was kept in a cage with a wooden bottom in order to address concerns that the effects of exposure to the phone could be due to heat emitted by the phone rather than to RF-EMR alone. Animals were sacrificed 24 hours after the last exposure and tissues of interest were harvested.
RESULTS: One hour of exposure to the phone did not significantly change facial temperature in either group of rats. No significant difference was observed in total sperm count between controls and RF-EMR exposed groups. However, rats exposed to RF-EMR exhibited a significantly reduced percentage of motile sperm. Moreover, RF-EMR exposure resulted in a significant increase in lipid peroxidation and low GSH content in the testis and epididymis.
CONCLUSION: Given the results of the present study, we speculate that RF-EMR from mobile phones negatively affects semen quality and may impair male fertility.

Matched MeSH terms: Electromagnetic Fields/adverse effects*
Fulltext Stochastic electromagnetic field propagation- measurement and modelling

Gradoni G, Russer J, Baharuddin MH, Haider M, Russer P, Smartt C, et al.

Philos Trans A Math Phys Eng Sci, 2018 Oct 29;376(2134).
PMID: 30373944 DOI: 10.1098/rsta.2017.0455

This paper reviews recent progress in the measurement and modelling of stochastic electromagnetic fields, focusing on propagation approaches based on Wigner functions and the method of moments technique. The respective propagation methods are exemplified by application to measurements of electromagnetic emissions from a stirred, cavity-backed aperture. We discuss early elements of statistical electromagnetics in Heaviside's papers, driven mainly by an analogy of electromagnetic wave propagation with heat transfer. These ideas include concepts of momentum and directionality in the realm of propagation through confined media with irregular boundaries. We then review and extend concepts using Wigner functions to propagate the statistical properties of electromagnetic fields. We discuss in particular how to include polarization in this formalism leading to a Wigner tensor formulation and a relation to an averaged Poynting vector.This article is part of the theme issue 'Celebrating 125 years of Oliver Heaviside's 'Electromagnetic Theory''.

Matched MeSH terms: Electromagnetic Fields
Analysis of model-based and model-free CEST effect quantification methods for different medical applications

Foo LS, Yap WS, Hum YC, Manan HA, Tee YK

J Magn Reson, 2020 01;310:106648.
PMID: 31760147 DOI: 10.1016/j.jmr.2019.106648

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) holds great potential to provide new metabolic information for clinical applications such as tumor, stroke and Parkinson's Disease diagnosis. Many active research and developments have been conducted to translate this emerging MRI technique for routine clinical applications. In general, there are two CEST quantification techniques: (i) model-free and (ii) model-based techniques. The reliability of these quantification techniques depends heavily on the experimental conditions and quality of the collected data. Errors such as noise may lead to misleading quantification results and thus inaccurate diagnosis when CEST imaging becomes a standard or routine imaging scan in the future. This paper investigates the accuracy and robustness of these quantification techniques under different signal-to-noise (SNR) levels and magnetic field strengths. The quantified CEST effect before and after adding random Gaussian White Noise using model-free and model-based quantification techniques were compared. It was found that the model-free technique consistently yielded larger average percentage error across all tested parameters compared to its model-based counterpart, and that the model-based technique could withstand SNR of about 3 times lower than the model-free technique. When applied on noisy brain tumor, ischemic stroke, and Parkinson's Disease clinical data, the model-free technique failed to produce significant differences between normal and abnormal tissue whereas the model-based technique consistently generated significant differences. Although the model-free technique was less accurate and robust, its simplicity and thus speed would still make it a good approximate when the SNR was high (>50) or when the CEST effect was large and well-defined. For more accurate CEST quantification, model-based techniques should be considered. When SNR was low (<50) and the CEST effect was small such as those acquired from clinical field strength scanners, which are generally 3T and below, model-based techniques should be considered over model-free counterpart to maintain an average percentage error of less than 44% even under very noisy condition as tested in this work.

Matched MeSH terms: Electromagnetic Fields
Fulltext Dry Thermotropic Glycolipid Self-Assembly:A Review

Hashim R, Zahid NI, Velayutham TS, Aripin NFK, Ogawa S, Sugimura A

J Oleo Sci, 2018 Jun 01;67(6):651-668.
PMID: 29760332 DOI: 10.5650/jos.ess17261

Also recognized as carbohydrate liquid crystals, glycolipids are amphiphiles whose basic unit comprises of a sugar group attached to an alkyl chain. Glycolipids are amphitropic, which means these materials form liquid crystal self-assemblies when dry (thermotropic) as well as when dissolved in solvents (lyotropic/surfactants) such as water. Many glycolipids are also naturally derived since these can be found in cell membranes. Their membrane and surfactant functions are largely understood through their lyotropic properties. While glycolipids are expected to play major roles as eco-friendly surfactants in the global surfactant market, their usefulness as thermotropic liquid crystal material is, to date, unknown, due to relatively lack of research performed and data reported in the literature. Understandably since glycolipids are hygroscopic with many hydroxy groups, removing the last trace water is very challenging. In recent time, with careful lyophilization and more consistent characterization technique, some researchers have attempted serious studies into "dry" or anhydrous glycolipids. Motivated by possible developments of novel thermotropic applications, some results from these studies also provide surprising new understanding to support conventional wisdom of the lyotropic systems. Here we review the dry state of glycosides, a family of glycolipids whose sugar headgroup is linked to the lipid chain via a glycosidic oxygen linker. The structure property relationship of both linear and anhydrous Guerbet glycosides will be examined. In particular, how the variation of sugar stereochemistry (e.g. anomer vs. epimer), the chain length and chain branching affect the formation of thermotropic liquid crystals phases, which not only located under equilibrium but also far from equilibrium conditions (glassy phase) are scrutinized. The dry glycolipid assembly has been subjected to electric and magnetic fields and the results show interesting behaviors including a possible transient current generation.

Matched MeSH terms: Electromagnetic Fields
Fulltext Measurement of extremely low frequency (ELF) magnetic flux in the vicinity of the overhead high voltage transmission line in Universiti Kebangsaan Malaysia

Faizal Mohamed, Irman Abdul Rahman, Ngu, Thieng Kui, Syazwani Mohd Fadzil, Firdaus Pozi, Amran Ab. Majid, et al.

Journal of Nuclear and Related Technologies, 2017;14(2):1-10.
MyJurnal

Electricity has become one of the necessities for human daily activities. The presence of electric
current produces electromagnetic fields (EMF) at extremely low frequency (ELF). The problem arises
when scientists suggests a possible connection between ELF exposure to human health and safety.
Concerned about the safety and health of students and staff, Universiti Kebangsaan Malaysia (UKM)
took the initiative to identify possible ELF sources and measure their exposure in various locations
around the UKM main campus in Bangi. This paper reports the results obtained from the monitoring
of the magnetic flux density at three identified locations in the vicinity of the overhead high-voltage
transmission line which transverses the university compound and compare the maximum value results
with the exposure limit suggested by the International Committee on Non Ionising Radiation
Protection (ICNIRP) for ELF. Measurements were done with an (Extech) Three Axis
Electromagnetic Field (EMF) Meter (Model 430826) to determine the magnetic flux density. The
lateral profile method was applied as the standard measurement methodology. Results showed that the
maximum value of the magnetic flux density was 12.5 mG, which is below the suggested ICNIRP
public exposure limit of 1000 mG, or in percentage ratio, 1.25% of ICNIRP public exposure limit.
Results from the statistical Kruskal-Wallis test showed that there is a significant difference in the
distributions of the magnetic flux densities at the different locations (P < 0.05). In conclusion, the
measured locations are still safe for people in short-term exposure. However, long-term exposure
measurements still need to be done to provide concrete data on the ELF-emission levels in UKM.

Matched MeSH terms: Electromagnetic Fields
Variations in occupational exposure to magnetic fields among welders in Malaysia

Man AK, Shahidan R

Radiat Prot Dosimetry, 2008;128(4):444-8.
PMID: 18045796

This study attempted to estimate the lifelong magnetic field (MF) exposures of a particular group of welders. Exposure was quantified via measurements, observations and interviews. It was found that these welders face a vast range of lifelong MF exposures depending on the welding processes and duration of the welding tasks performed. This may explain the inconsistency in the results of studies of MF exposures on human health. The mere assessing of the MF exposure levels through spot measurements does not give an overall picture of the total amount of exposure received by the welders as some of these workers performed the welding task throughout the day, whereas others performed this as a part of their job. The exposure to various chemicals in the fume may complicate the interpretation of the elevated health risk among the welders.

Matched MeSH terms: Electromagnetic Fields*
Transient electro-magneto-hydrodynamic two-phase blood flow and thermal transport through a capillary vessel

Mirza IA, Abdulhameed M, Vieru D, Shafie S

Comput Methods Programs Biomed, 2016 Dec;137:149-166.
PMID: 28110721 DOI: 10.1016/j.cmpb.2016.09.014

Therapies with magnetic/electromagnetic field are employed to relieve pains or, to accelerate flow of blood-particles, particularly during the surgery. In this paper, a theoretical study of the blood flow along with particles suspension through capillary was made by the electro-magneto-hydrodynamic approach. Analytical solutions to the non-dimensional blood velocity and non-dimensional particles velocity are obtained by means of the Laplace transform with respect to the time variable and the finite Hankel transform with respect to the radial coordinate. The study of thermally transfer characteristics is based on the energy equation for two-phase thermal transport of blood and particles suspension with viscous dissipation, the volumetric heat generation due to Joule heating effect and electromagnetic couple effect. The solution of the nonlinear heat transfer problem is derived by using the velocity field and the integral transform method. The influence of dimensionless system parameters like the electrokinetic width, the Hartman number, Prandtl number, the coefficient of heat generation due to Joule heating and Eckert number on the velocity and temperature fields was studied using the Mathcad software. Results are presented by graphical illustrations.

Matched MeSH terms: Electromagnetic Fields*
Fulltext Microwave bio-sensor based on symmetrical split ring resonator with spurline filters for therapeutic goods detection

Alahnomi RA, Zakaria Z, Ruslan E, Ab Rashid SR, Mohd Bahar AA, Shaaban A

PLoS One, 2017;12(9):e0185122.
PMID: 28934301 DOI: 10.1371/journal.pone.0185122

A novel symmetrical split ring resonator (SSRR) based microwave sensor with spurline filters for detecting and characterizing the properties of solid materials has been developed. Due to the weak perturbation in the interaction of material under test (MUT) and planar microwave sensor, spurline filters were embedded to the SSRR microwave sensor which effectively enhanced Q-factor with suppressing the undesired harmonic frequency. The spurline filter structures force the presented sensor to resonate at a fundamental frequency of 2.2 GHz with the capabilities of suppressing rejected harmonic frequency and miniaturization in circuit size. A wide bandwidth rejection is achieved by using double spurlines filters with high Q-factor achievement (up to 652.94) compared to single spurline filter. The new SSRR sensor with spurline filters displayed desired properties such as high sensitivity, accuracy, and performance with a 1.3% typical percentage error in the measurement results. Furthermore, the sensor has been successfully applied for detecting and characterizing solid materials (such as Roger 5880, Roger 4350, and FR4) and evidently demonstrated that it can suppress the harmonic frequency effectively. This novel design with harmonic suppression is useful for various applications such as food industry (meat, fruit, vegetables), biological medicine (derived from proteins and other substances produced by the body), and Therapeutic goods (antiseptics, vitamins, anti-psychotics, and other medicines).

Matched MeSH terms: Electromagnetic Fields
Assessment of radiofrequency/microwave radiation emitted by the antennas of rooftop-mounted mobile phone base stations

Keow MA, Radiman S

Radiat Prot Dosimetry, 2006;121(2):122-7.
PMID: 16357026

Radiofrequency (RF) and microwave (MW) radiation exposures from the antennas of rooftop-mounted mobile telephone base stations have become a serious issue in recent years due to the rapidly evolving technologies in wireless telecommunication systems. In Malaysia, thousands of mobile telephone base stations have been erected all over the country, most of which are mounted on the rooftops. In view of public concerns, measurements of the RF/MW levels emitted by the base stations were carried out in this study. The values were compared with the exposure limits set by several organisations and countries. Measurements were performed at 200 sites around 47 mobile phone base stations. It was found that the RF/MW radiation from these base stations were well below the maximum exposure limits set by various agencies.

Matched MeSH terms: Electromagnetic Fields/adverse effects*
Fulltext Effect of Short-Term Mobile Phone Base Station Exposure on Cognitive Performance, Body Temperature, Heart Rate and Blood Pressure of Malaysians

Malek F, Rani KA, Rahim HA, Omar MH

Sci Rep, 2015;5:13206.
PMID: 26286015 DOI: 10.1038/srep13206

Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipse(TM)) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P's > 0.05).

Matched MeSH terms: Electromagnetic Fields
Prospects of plasma immersion ion implantation and deposition (PIlI & D) in the biomaterials field in Malaysia and south East Asia

Mohamed MH

Med J Malaysia, 2004 May;59 Suppl B:19-20.
PMID: 15468798

One of the emerging technologies in the area of plasma processing is plasma immersion ion implantation (PSII). The paper addresses the merits offered by the PSII technique especially in the area of biomaterial processing. Worldwide development status as well as the drive towards commercial applications is elaborated in an attempt to draw the attention to the importance of the process for Malaysia as well as south East Asia.

Matched MeSH terms: Electromagnetic Fields*
Electromagnetic (EM) absorption reduction in a muscle cube with metamaterial attachment

Faruque MR, Islam MT, Misran N

Med Eng Phys, 2011 Jun;33(5):646-52.
PMID: 21216175 DOI: 10.1016/j.medengphy.2010.12.004

The purpose of this paper is to calculate the specific absorption rate (SAR) reduction in a muscle cube with metamaterial attachment. The finite-difference time-domain (FDTD) method has been used to evaluate the SAR in a realistic anatomically based model of the muscle cube. In this paper, we have designed the single-negative metamaterials from a periodic arrangement of split ring resonators (SRRs). By properly designing the structural parameter of the SRRs, the effective medium parameter can be tuned negative at the 900 MHz and 1800 MHz bands. Numerical results concerning the SAR values in the muscle cube in the presence of resonators exhibit significant SAR reduction. These results can provide useful information when designing safety-compliant mobile communication equipment.

Matched MeSH terms: Electromagnetic Fields*
Fulltext Role of Phase-Dependent Dielectric Properties of Alumina Nanoparticles in Electromagnetic-Assisted Enhanced Oil Recovery

Adil M, Lee KC, Zaid HM, Manaka T

Nanomaterials (Basel), 2020 Oct 06;10(10).
PMID: 33036153 DOI: 10.3390/nano10101975

The utilization of metal-oxide nanoparticles in enhanced oil recovery (EOR) has generated considerable research interest to increase the oil recovery. Among these nanoparticles, alumina nanoparticles (Al2O3-NPs) have proved promising in improving the oil recovery mechanism due to their prominent thermal properties. However, more significantly, these nanoparticles, coupled with electromagnetic (EM) waves, can be polarized to reduce water/oil mobility ratio and create disturbances at the oil/nanofluid interface, so that oil can be released from the reservoir rock surfaces and travelled easily to the production well. Moreover, alumina exists in various transition phases (γ, δ, θ, κ, β, η, χ), providing not only different sizes and morphologies but phase-dependent dielectric behavior at the applied EM frequencies. In this research, the oil recovery mechanism under EM fields of varying frequencies was investigated, which involved parameters such as mobility ratio, interfacial tension (IFT) and wettability. The displacement tests were conducted in water-wet sandpacks at 95 °C, by employing crude oil from Tapis. Alumina nanofluids (Al2O3-NFs) of four different phases (α, κ, θ and γ) and particle sizes (25-94.3 nm) were prepared by dispersing 0.01 wt. % NPs in brine (3 wt. % NaCl) together with SDBS as a dispersant. Three sequential injection scenarios were performed in each flooding scheme: (i) preflushes brine as a secondary flooding, (ii) conventional nano/EM-assisted nanofluid flooding, and (iii) postflushes brine to flush NPs. Compared to conventional nanofluid flooding (3.03-11.46% original oil in place/OOIP) as incremental oil recovery, EM-assisted nanofluid flooding provided an increase in oil recovery by approximately 4.12-12.90% of OOIP for different phases of alumina. It was established from these results that the recovery from EM-assisted nanofluid flooding is itself dependent on frequency, which is associated with good dielectric behavior of NPs to formulate the oil recovery mechanism including (i) mobility ratio improvement due to an electrorheological (ER) effect, (ii) interfacial disturbances by the oil droplet deformation, and (iii) wettability alteration by increased surface-free energy.

Matched MeSH terms: Electromagnetic Fields

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