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Electromagnetic frequency detector is a scientific instrument for measuring or detecting frequency by using electromagnetic theory. As we know, electromagnetic frequency detector is useful in electrical field, it is very sensitve and can detect even a tiny object in micrometres in a extremely high or low frequency range. It useful in medical field too. For example, it can use as a sensor to detect blockage in the human heart. The most interesting is, EMF Detector can be use as ghost hunting device.Â EMF detector can locate and track paranormal energy sources. If the EMF meter showing higher reading than normal 2.0-7.0G which normal range is 0.1-10mG ), an unknown entity is detected. We will be discussing several recent and new applications of EMF detector throughout the whole report, and the future prospects of EMF detector in the end.
The purpose of this study was to understand electromagnetic frequency detector application and its principle of operation. Nowadays, electromagnetic frequency detector is widely use.
The first electromagnetic frequency detector is invented at 1742 by Andrew Gordon , which is use as a device to warn approaching thunder storms and lightnings. The second is invented to detect ghost by Herman Bustamante at 1859. At 1888, Hertz use this detector to measure wavelength of light. Then EMF detector is used to detect radio frequency at 1922.
Starting of 1900, electromagnetic frequency detector become much more famous and commonly used [refer 1] due to its characteristic and useful application.
SUMMARY OF STUDY ON PROCESS OF DUAL-FREQUENCY ELECTROMAGNETIC CONFINEMENT AND SHAPING FOR STAINLESS STEEL - JOURNAL OF MATERIAL PROCESSING TECHNOLOGY
Written by: Kee Swee Yen (B010810023)
Two magnetic fields are separately designed and controlled for the dual-frequency electromagnetic confinement and shaping stainless steel (EMCS). A lower frequency magnetic field is used to produce an electromagnetic force while a higher frequency is used to heat and melt materials without the influence of the latter. The fundamental of EMCS is that two heat energies will be acted on the materials; induction heat and electromagnetic force.
Pm + Pr = Pg
This equation, electromagnetic force(Pm) adding to surface tension(Pr) equals to gravity of the molten metal(Pg) is used to achieve good coupling temperature and electromagnetic force to stably confined the molten metal. Coupling of the temperature field and the electromagnetic force can be optimized with a dual-frequency EMCS and a separately designed inductors' size and shape.
The lower frequency magnetic force is favourable to the electromagnetic force and is selected for shaping the inductor. Whereas, the higher frequency of the magnetic force is favourable to the induction heat which heats the inductor. The temperature is measured with a thermocouple and the magnetic flux density is obtained through this equation : Bm = âˆš8E/(Ï€2fND2)
Through the research, it is found that 30mm distance between heating inductor and shaping inductor is preferable to avoid the clashes of two different magnetic fields. The screen is installed below the shaping inductor to reduce induction heat and achieve directional solidification of the molten metal. To obtain a stable shape, the slope of the electromagnetic force must be consistent with the gravity slope. The electromagnetic force of a dual-frequency EMCS can be adjusted by controlling the current of the shaping inductor, and therefore one force could adjust temperature and position of molten metal without the effects of another electromagnetic force.
SUMMARY OF 3D LOW FREQUENCY ELECTROMAGNETIC MODELLING OF THE HUMAN EYE WITH BOUNDARY ELEMENTS: APPLICATION TO CONDUCTIVE KERATOPLASTY
Written by: Kee Swee Yen (B010810023)
Conductive keratoplasty (CK) is a surgical technique where a thin electrode penetrates the cornea and sends pulsed radio-frequency energy the surrounding eye tissue. The electromagnetic energy is dissipated into heat energy in the tissue which shrinks and tightens thermally the collagen lamellae. This technique allows doctors to correct the shape of the cornea and cure common eye types of disease like far-sightedness and astigmatism. This research is to make a 3D boundary element model of the human eye to find current density distribution in the different eye tissues in CK treatment. The research includes the behavior of the human eye in the low frequency range, and how it acts as a complex imperfect conductive body in response to a high voltage signal.
Biological tissues have different conductivities and permitivities and electrical field are mostly preferable in the exposure of biological tissues to high voltage and low intensity systems. Thus, calculations for low frequency electromagnetic field requires macroscopic Maxwell equations and boundary element method (BEM) is used to solve the electric problem of the 3D eye-model. Continuous and discontinuous collocation nodes are combined, where potentials are assigned to continuous nodes and electric field are assigned to discontinuous nodes. This ensures the continuity potential between adjacent elements and decrease complications.
Therefore the Ck treatment is a harness of electric fields, to thermally reshape cornea and cure eye-related complications.
Very Low Frequency Electromagnetic
Field Detector With Data Acquisition
By : Muhammad Shalihin Bin Aris
Electromagnetic oscillating fields occur in very low frequency (VLF) range of spectrum and it is weak and in normal condition it is difficult to be detected. The VLF usually appears during thunderstorm. The man-made VLF electromagnetic fields are stronger and cause the bad effect of health.
The development of triaxial 'VLF gausemeter' can be used to control the radiation. The VLF gausemeter is designed to measure magnetic flux density and frequency across the VLF BW. The features to design this including; automatic or manual range selection, data logging, single-axis mode, peak hold, RS-232 communication port and analogue recorder output.
Electromagnetic field is generated by man-made system such as high power transmission line. The EMF radiation causes the biological system such as leukaemia. The measured of magnetic field can be any one of vector component Bx, By, and Bz or resultant of periodic magnetic field.
The detection network is using three utilizes orthogonal multi turn copper that react to a time varying magnetic field. The field measurements are made externally by RS-232 communication port and analogue recorder output. As a conclusion, a VLF gaussmeter portable high-resolution, good linearity and frequency to measure the width of BW regular man-made EMFs.
Analytical Modelling In Low Frequency Eletromagnetic
Measurement Of Steel Casing Properties
By: Muhammad Shalihin bin Aris
The measurement of oil -well steel casing properties is important for assessment of the physical condition of the casing. Actually, low frequency electromagnetic measurement of casing properties is referring to the measurement impedance of single coil. In single coil impedance measurement, the sensitivity is based on selection the excitation frequency, while for two coil the excitation spectrum and axial separation between the coils.
Published study for this topic mainly experimental and more focused on certain region of space and frequency distribution. Based on work of Dodd and Deeds, they present the analytical model in order to analyse the whole space-frequency characteristic. Their model prediction and sensitivity is consistent with the known effect of separation and excitation frequency on the measurement.
The effect of coil separation and the measurement of excitation frequency casing properties is describes in sensitivity analysis. There are two separate frequency band pick-up voltage spectrum that can be employed foe simultaneous measurement. The prediction of the system to any excitation waveform can be used in this model.
As a conclusion, the model of Dodd and Deeds can be used in order to apply in optimal design of these systems.
Summary of Measurement of Permeability and Ferrite/austenite Phase Fraction Using a Multi-frequency Electromagnetic Sensor
Written by Erma Nurrul bt Hazizan (B010810024)
Measurement of permeability and ferrite/austenite phase fraction using a electromagnetic frequency was chosen because it is more cheaper, have a fast response and dust and water will not affected the elecromagnetic frequency. Electromaegnetic frequency was use to seperate a a ferrite partical to other samples. From whole percentage of ferrite, the transformation from paragmagnetic to ferromagnetic phase below the temperature 770oC was monitored by electromagnetic frequency techniques based on zero crossing frequency features. To prove that this method is verify, comparison with analytical method was made using this equation :
Î± = equation viarable = frequency
Âµ = permeability of conducting plate = peak frequency
As a result, measurement of effective permeability between actual and measure method shows that a good fit between them. Comparison with real microstructurs modelling using FEMLAB was made too. Using electromagnetic frequency to the ferrite, it increases the permeability when ferrite fraction is increase compared to FEMLAB. Actual ferrite fraction images was compared to electromagnetic frequency sensor and show that the percentage of error is 8%. As conclusion, usage of electromagnetic frequency sensor is the best way to find a effective permeability and ferrite volume fraction.
Summary of Frequency Modulated Electromagnetic Neural Stimulation Enhances Cutaneous Microvascular Flow in Patient with Diabetic Neurophaty.
Written by Erma Nurrul bt Hazizan (B010810024)
This study was about safe and effective treatment to cutaneous microvascular function of painful diabetic neurophaty using frequency modulated electromagnetic neutral stimulation. Thirty one patient with painful diabetic neurophaty has been selected to investigate this effect on them. The treatment were done rondomised, double blind, have session of placebo to compare, and frequency modulated electromagnetic neural stimulation with 1 week washout. At the end of the session and four month after the study was completed, patient were evaluated at baseline. Electromagnetic frequency belived that can make improvement to peripharal nerve function. When frequency modulated electromagnetic neural stimulation was applied to patient, it belived that this treatment may effect the microvascular blood flow. Laser Doppler was used to measure cutaneous capillary blood flow on three different areas of the dorsal surface of the foot. The result between two sequence assignment groups that is placebo and frequency modulated electromagnetic neural stimulation were slightly different from each other. Significant increase of cutaneous blood flow were analyzed in resting conditions but flow response to thermal stimulation remained unchanged. Within the series of treatment that have been made for three weeks, there were no changes, but when at 4 month after the study, there were some changes regarding to increasing in 52% of microvascular blood flow measured on the dorsal surface of the foot by laser Doppler in resting conditions. It can be conclude than during treatment with frequency modulated electromagnetic treatment, the skin of individuals at the microvascular level response with generates diabetes. As a conclusion, to comfirm this findings, there must be a futher study from clinical, biogical, and instrumental measure.
Ultra High Frequency Electromagnetic Wave Detector
for Diagnostic of Metal Clad Switchgear Insulation
Literature review summary : Saiful Amin b. Kamaruddin
In this journal, the ultra high frequency is use for tracking discharges in Metal Clad Switchgear (MCS) and its performance. The ultra high frequency use more than hundred megaherth transmitted though a MCS for tracking discharges.
The Metal Clad Switchgear is use for many year sometimes have failure operate. So, the condition of MCS must diagnose. This tracking, diagnose only under moist condition,usually takes years before it causes damage. The partial discharges (PDs) is use for the purpose of assessing the insulating condition of operation of MCS. The false indications due to electrical noise tracking use on-line PD tests. At the MCS door gap, traveling wave propagation on conductors, feeders, grounding wire, and measuring cable UHF wave transmitted and tracking the failure of MCS. The attenuation increases with increasing frequency. From the analysis, there have differences about 5dBV between the spectrum analyzer and the UHF wave detector sensitivities. According to J.Ozawa when tracking more than 10000pc UHF wave detector not stable because of the time change of the discharge level and the sensitivity limit of the detector. No signal when tracking range 100Mhz at both.
I can conclude from this journal that the ultra high frequency electromagnetic just detect in range 400 - 1400Mhz for diagnostics of Metal Clad Switchgear insulation. The UHF can be improve in future to diagnosis Metal Clad Swithgear insulation.
Dual-frequency electromagnetic confinement of liquid aluminum
Literature review summary : Saiful Amin b. Kamaruddin
This journal is about dual-frequency electromagnetic confinement of liquid aluminum. Journal analysis about developed to smelt the solid metal and confine the molten metal into a final shape without any contamination pressure of 350 and 50Khz. To stable pressure of height of liquid metal, suitable pattern of induction heating and electromagnetic confinement induction is design.The main purpose of journal is about research to use a dual- frequency electromagnetic field to achieve this complicated process.
In the journal, electromagnetic casting (EMC), electromagnetic levitation (EML) and cold crucible induction melting technology are use for non- contamination process. According to Shuangming Li, aluminum samples with circular and rectangular-form cross sections have been confined by a single frequency electromagnetic field. There have problem use the EMC, EML and cold crucible induction.. So new process melt to a near-net shape by alternating electromagnetic field without any contamination are develop. The combination patterns of dual-frequency electromagnetic field develop by principle of induction heating,. . According to the process of dual-frequency electromagnetic shaping is available for controlling and manipulating, easily realizing the complex shape confined without any mold.
In conclusion, The upper and lower combination pattern of dual-frequency electromagnetic is better than dual-frequency confinement of liquid metal. The dual-frequency produced of 350 and 50kHz can be calculated as sum of two single-frequency electromagnetic pressure by using superposition principle.
SUMMARY OF RESEARCH ON DETECTION AND RECOGNITION OF PARTIAL DISCHARGE IN GAS INSULATED SYSTEM
Written by : Ahmad Zakuan Bin Ahmad Dahalan (B010810151)
This journal explains the usage of electromagnetic that can be used as one of safety instrument in industrial application. Partial Discharge (PD) in Gas Insulated System (GIS) will cause major insulation damage. The solution is to detect and locate PD source inside GIS is the electromagnetic wave that emit from PD source is detect by using ultra-high frequency. In this era, on-line system is widely used to monitor safety in industrial. Ultra-high frequency is the best way to detect PD source with less effect to disturbances. Besides, using UHF in on-line system can detect fault effectively and can predict the maintenance needed. Narrow band UHF is designed in PD detection system. The process of the system is using the antenna inside GIS and the electromagnetic wave from PD will detect the antenna. Spectrum analyzer will measure frequency of the signal. Spectrum of background noise is taken as reference spectrum. So, disturbances that exist can be eliminated from PD signal in measurement.
Two types of measurement in PD are used in UHF; broad band and narrow band method. Broad band technique is detected PD signal in time domain over a broad frequency range. In narrow band technique, it needs only few MHZ to measure bandwidths. This concept is normally used in spectrum analyzer.
Four types of defect experiment are executed. The defects are protrusion on the bus bar, protrusion on the enclosure, particle on the barrier surface and void barrier. Protrusion on bus bar is analysed because of production of a relatively stable, quantifiable and reproducible PD. In Protrusion on bus bar, a wire is attached to bus bar surface. In protrusion on the enclosure a wire is attached perpendicular to surface. In Particle on the barrier surface a wire is attached to surface barrier. In void barrier, an earth barrier is inserted in block of epoxies resin to let block generate PD easily and many void is attached to bus bar surface. All techniques are used to experiment all types of defects. Result show that time domain waveform of different defect has different distribution characteristic and time domain waveform for same defect is similar distribution characteristic and different amplitude. So, PD types in GIS is possible to identify.
Summary on Pulsed electromagnetic methods for defect detection and characterisation
Written by : Ahmad Zakuan Bin Ahmad Dahalan (B010810151)
Electromagnetic flux leakage (MFL) is a method to trace defect location. The disadvantage of MFL is due to limitation in detecting sizing capabilities defect. To solve this, Pulsed magnetic flux leakage (PMFL) technique using time frequency signal is used, but sizing of sub surface defect has its problems. In this journal, pulsed magnetic reluctance (PMR) is a new method used and combined into dual PMFL/PMR for surface and sub surface defect in ferromagnetic material. PMFL is used to locate surface and sub-surface defect and PMR is used for subsurface defect characteristic capabilities defect. This combined technique can provide detection of defect characteristic capabilities for flux leakage-base inspection system using time frequency signal processing technique. In industries, the process needs to be fast, reliable and cost effective. PMFL and PMR method is sensitive to depth information in different types of defects. Leakage field on material surfaces are types of surface breaking defect but not sub surface defect. The field strength around magnetic circuit consists of ferrite core and sample under test is measured in PMR. PMR is more sensitive to sub-surface rather than PMFL. In PMFL, magnetic field amplitude rate change can locate defect and time peak value to provide depth information about surface defect.
For experiment, a steel block is used. The purpose of this experiment is to locate defect and get the depth information. RMS leakage amplitude of PMFL signal is used to locate defect. Depth of defect is high when the time to peak of PMFL long. For sub surface experiment, the defect in steel can be located through minimum RMS value of PMFL. In sub surface, PMFL cannot measure depth of defect but PMR is used to measure depth by measure time delay of time to peak PMR.
From the experiment, analysis of RMS amplitude of induced PMFL signal is used to locate surface and sub surface defect and time to peak of PMFL signal can be used to measure defect depth. Defect depth is proportional to PMFL time to peak. PMR supports the PMFL method for sub-surface defect. Sub surface defect depth has near linear relationship to time to peak of PMR signal. The conclusion is, combining PMFL and PMR methods are the best way to detect surface and sub surface defect in ferromagnetic component and structure.
Far-Infrared Ferromagnetic Resonance of Magnetic Garnet for High Frequency Electromagnetic Sensor
Reviewed by Low Siew Yi (B010810205)
Nowadays, most electronic device using high frequency for high speed and large amount of data communication. So, we using MO effect,which have low invasion of electromagnetic field and rapidly give respond to the change of magnetic field, but, in high frequency, the permeability of ferrite garnet will be decrease which will decreasing MO effect. This can solve by using ferromagnetic resonance (FMR). Large induce magnetic moment are necessary to enhance MO effect for high frequency region.
In the experiment, films were prepared by liquid phase epitaxy technique and FMR were investigated in high frequency region and the anisotropy field is parallel to the film plane. Using ESR to measure X(9GHz) and Q band(34GHz), gun diode measure frequency between 30 GHz and 315 GHz. In high frequency region, DC magnetic field is applied to magnetic garnet film, ferromagnetic resonance will induce magnetic moment and will rotate the plane of polarization.
High frequency magnetic field generate around wire, it detect by MO effect. The MO signal depending on the frequency at the difference DC magnetic field [refer1]. MO effect detected at sharp peak. The peak position will be shift to higher frequency when we increased magnetic field. To enhance the MO signal,we induce magnetic moment by using FMR of magnetic garnet. FMR spectrum measure at 9GHz and 60GHz show in . For this low and high frequency, FMR measure by field modulation technique and transmission mode respectively. We observe that it have a splittig large peak, the splitting is cause by magnetostatic wave for FMR resonance spectra at 9GHz.At 60GHz ,the large peak is due to FMR of magnetic garnet and small peak is due to EPR of DPPH.
Resonance field vs frequency and magnetic field vs enhance frequency are a straight line graph[refer5] which show both frequency have a good relationship between each other, this can determine the enhancement of MO signal. Kittel's equation show the relationship of frequency and FMR resonance field. For frequency below 100GHz, the garnet material is the best material for high field magnetic sensor device. This is due to the resonance intensity is exceedig decreases at above 100GHz. The larger the frequency, the smaller the FMR peak [refer4].
A non-contact proximity sensor with low frequency electromagnetic field
Reviewed by Low Siew Yi(B010810205)
Non-contact proximity sensor (NPS) send and receive signal by using a single probe, and use low frequency electromagnetic field to monitor a object. Advantages of NPS is cheaper, the probe is very flexible and this sensor is sensitve to object's thickness.
Oscillator circuit is the Priciple of operation [refer6]. The metalic wire is a sensing element that can detects somethings that coming near. Time period t1 t2 t3 t4 use to determine the frequency, f of oscillator. Oscillaor f will increase by change t1, which t2 t3 t4 remain unchanged.When frequency changing, it will affect the charge flowing through wire. 2 oscillograms of point (1) [refer6] with an oscilltor without wire and with metalic wire[refer 7]. t1 is extended by metalic wire. At ta1 electrical supply source charge capacitor C1. After charging, current will flow through wire and it will last for tb1 .At tb1,C1 does not vary, so it remain constant. When the C and wire fill with sufficient positive charge, the invertor I1 will be turn on. Current in sensing metalic wire will change and send electromagnetic radiation into the space according to the electromagnetism by maxwell formula. Material around the wire will decide the volume of the "displacement current". When an object closer to the wire probe, it induces a frequency change of the oscillator which will show the distance of the object. we can prove it by doing experiment. First experiment, a rectangular metallic plate connected to a wire which act as probe. If we moving a thick wood closer to the probe, the oscillator frequency will be influence [refer 9]. The change in frequency is induce by wood under different initial oscillation frequency,fosc of the sensor. The larger the fosc, the larger the change in frequency. Second experiment, by using difference object plates moving closer to a probe in parellal[refer10]. From the figure[refer10],we observe that distance of object will be influence the fosc, and frequency increase depending on material. The next experiment, we using multi layer of PVC plastics plate to test the thickness effect[refer11].From the figure[refer11], we observe that the thicker the object, the larger the change in frequency. By increasing the fosc or the sample time can improve the sensitivity of probe.
The applications of electromagnetic detector in recent case studies have been discussed and summarise in 12 literature reviews. It is observed that EMF detector can be used widely in any fields, medical wise to industrial application. Pulse electromagnetic detector is used as defection detector, a device so useful in ferromagnetic structures whereas in piping system, electromagnetic frequency detector could be used to detect gas or liquid leakages especially in bend-structures without point-to-point inspection, thus saving time and cost. Other than that, EMF detector enables steel casting, steel shaping and molten metal confinement easier, saves energy and provides better accuracy. EMF detector plays an important role in medical fields too. It is proven that EMF could improve neuropathy systems in a diabetic patient, and provides a 3D eye model for eye surgery studies.
Through observations, it is concluded that EMF detector has been used extensively in this technological era. With such desirable qualities and versatility of an EMF detector, there are already a few references to new applications in year 2010 itself. The researches in Korea University are said to be creating a long term health-monitoring networks which can be embedded in the skin such as electrocardiography. Essentials oils like Rose, Lavender, Coffee, are said to effect human body natural frequencies. Chances of getting common diseases such as flu and cancer could be decreased by manipulating the frequencies with essential oils. All these ideas are healthily contributing to the future prospects to the electromagnetic frequency detector.