Wire Coil Research Articles

Design of orthogonal directional shear horizontal electromagnetic acoustic transducer

This research proposed an electromagnetic acoustic transducer (EMAT) for generating and receiving orthogonal directional shear horizontal (ODSH) guided waves in the metal plate-like structure. The proposed EMAT generates the fundamental mode of SH wave in the horizontal and vertical direction in the plane of the test sample. The ODSHEMAT combines a new Chevron-like coil design which generates an eddy current effect in the skin depth of the plate surface, and a periodic permanent magnet that applies a static magnetic field vertically with a periodicity equal to its wavelength. The direction of the resultant Lorentz force acting on the test surface-controlled PPM underneath a specific chevron angle of the coil wire. The constructive interference of propagated waves has been developed in the orthogonal directions, enhancing the ultrasonic signals and improving the signal-to-noise ratio. A finite element simulation has been carried out with a thin aluminum plate, keeping the proposed EMAT at the center of the sample. Further, the simulation results show good agreement with the proposed design.

Thermal-hydraulic characteristics of FLiBe in annuli with helical wire

A fully tight-fitting triangular wire coil is used to enhance heat transfer of FLiBe in the annular channel for the first time. The numerical simulations of annular channels with triangular wire coil were performed with three helical pitches, three annular widths, and one equilateral triangle corresponding to Reynolds number of 4000–10000. It is found that adding triangular wire coil generates a vortex and reduces significantly the lengths of flow and thermal entrance regions of the annular channel. The local Nusselt number for peripheral point is extremely non-uniform. The Nusselt number decreases with annular width and helical pitch increase. The Nusselt number of enhanced annular channel is 1.45–1.98 times that of smooth annular channel. The overall performance of annular channel with helical pitch of 15 mm and annular width of 10 mm is best by using the principle of entropy generation. However, by using the performance evaluation criteria, the annular channel with helical pitch of 15 mm and annular width of 19.4 mm is best when the Reynolds number is less than or equal to 5500. And the annular channel with helical pitch of 20 mm and annular width of 19.4 mm is best at the high Reynolds number.

Design and Manufacture of Millimeter-Scale 3D Transformers for RF-IC.

The development of radio-frequency integrated circuits (RF-IC) necessitates higher requirements for the size of microtransformers. This paper describes millimeter-scale 3D transformers in millimeter-scale, solenoidal, and toroidal transformers manufactured using Micro-electromechanical Systems (MEMS). Two through-silicon via (TSV) copper coils with a high aspect ratio are precisely interleaved on a reserved air core (magnet core cavity) with a vertical height of over 1 mm because of the thickness of the substrate, which increases the performance while reducing the footprint. The effects of the wire width, coil turns, magnetic core, and substrate on the performance of the two transformers are discussed through numerical simulations. When an air core is present, solenoidal transformers are better than toroidal transformers in terms of performance and footprint; however, the gap decreases when the size is reduced. Additionally, the magnetic core significantly improves the performance of the toroidal transformer compared to that of the solenoid. Thus, the toroidal transformer has a higher potential for further size reduction. The two types of transformers were then manufactured completely using MEMS and electroplating. This paper discusses the influence of various parameters on millimeter-scale 3D transformers and realizes processing in silicon, which provides the foundation for integrating transformers in a chip.

Pembuatan Sensor Suhu Berbahan Kawat Kumparan dengan Indikator Intensitas Cahaya

Pembuatan Sensor Suhu Berbahan Kawat Kumparan dengan Indikator Intensitas Cahaya

Characteristics of Magnetic Resonance Wireless Power Transfer Across Gap Distance Using Metallic Wire Coils

Characteristics of Magnetic Resonance Wireless Power Transfer Across Gap Distance Using Metallic Wire Coils

Heat transfer enhancement of the f-MWCNT- Fe2O3/Water hybrid nanofluid with the combined effect of wire coil with twisted tape and perforated twisted tape

The impact of various variables on thermal conductivity and rheological behavior, such as nano particle weight concentration and temperature, and also the cumulative effects of coil ratio (CR = 3, 4) of wire coil insert and twist ratio (TR = 3, 4 and 5) of twisted tape (TT) and perforated twisted tape (PTT) on heat transfer coefficient and friction factor characteristics is explored. Nanofluids containing particles with weight percentages of 0.01%, 0.02%, and 0.03% were produced by dispersing functionalized multi-walled carbon nanotubes (f-MWCNTs) 60% by weight and Fe2O3 nanoparticles 40% by weight in distilled water and stabilizing them with an ultrasonic probe. The KD-2 Pro thermal analyzer and Rheometer are used to measure the thermal conductivity and viscosity of the hybrid nanofluids. The impact of various factors on the heat transfer and pressure drop is investigated, including Reynolds number, nanoparticle concentration, TR and CR of TT, PTT and WC. The findings clearly show that higher content of nanoparticles increases heat transfer as well as pressure drop. In contrast to the base coolant, the enhancement in heat transfer and friction factor is 21.66%–31.66% and 1.14 times, respectively. In comparison to a plain tube passing through 0.03 wt % hybrid nanofluid, the enhancements in heat transfer and friction are 32.31%–94.03%, 43.94%–141.07%, and 1.09 times, 1.13 times for the combined effect of TT and PTT having wire insert at ratio's of twist and coil are 3, respectively. Furthermore, UV–vis spectroscopy is being used to assess the stability of the prepared nanofluids, which is found to be acceptable. FESEM is used to determine the detailed surface properties.

Synthesis of magnetic nanocarbon using palm oil as the green precursor via microwave-assisted arc for wastewater treatment

The presence of metal with microwave irradiation has always invited controversial arguments as the metal will catch on fire easily. But interestingly, researchers found that arc discharge phenomena provide a promising way for molecule cracking to synthesize nanomaterials. This study developed a single-step yet affordable synthesis approach that combines microwave heating and arcing in transforming crude palm oil into magnetic nanocarbon (MNC), which can be considered a new alternative for the palm oil sectors. It involves synthesizing the medium at a partial inert condition with constant coiled stainless steel metal wire (dielectric media) and ferrocene (catalyst). This approach successfully demonstrates heating at a temperature ranging from 190.9 to 472.0 °C with different synthesis times (10–20 min). The produced MNC shows formations of spheres with average sizes of 20.38–31.04 nm, mesoporous structure (SBET: 14.83–151.95 m2/g), and high content of fixed carbon (52.79–71.24wt%), and the ratio of the D and G bands (ID/IG) is 0.98–0.99. The formation of new peaks in the FTIR spectra (522.29–588.48 cm−1) supports the appearance of the FeO compounds from the ferrocene. The magnetometer shows high magnetization saturation (22.32–26.84 emu/g) in ferromagnetic materials. The application of the MNC in wastewater treatment has been demonstrated by evaluating their adsorbent capability with Methylene Blue (MB) adsorption test at a different concentrations varying between 5 and 20 ppm. The MNC produced at synthesis time (20 min) shows the highest adsorption efficiency (10.36 mg/g) compared to others, with 87.79% removal of MB dye. As a result, the value for Langmuir is not promising compared to Freundlich, with R2 being around 0.80, 0.98, and 0.99 for MNC synthesized at 10 min (MNC10), 15 min (MNC15), and 20 min (MNC20), respectively. Hence, the adsorption system is in a heterogeneous condition. The microwave-assisted arcing thereby presents a promising approach to transforming CPO into MNC that could remove the hazardous dye.

Numerical investigations of turbulent heat transfer enhancement in circular tubes via modified internal profiles

Convective heat transfer enhancement in turbulent pipe flows via patterned surface textures is studied numerically via large eddy simulation (LES). The Reynolds and Prandtl numbers of the flow are 90,000 and 0.836, respectively. The patterned surface textures consist of ellipsoidal inward-facing elements, a wire coil, and spiral corrugations. The governing equations are solved on three-dimensional grids with the finite volume method using second-order temporal and spatial schemes. The mean Nusselt number and friction factor are calculated in each textured pipe and compared to an untextured baseline configuration. The inward-facing ellipsoidal elements showed the best performance yielding 22 − 42 % heat transfer enhancement with 41 − 97 % pressure loss penalty. The mechanisms driving convective heat transfer enhancement are examined via order-of-magnitude analysis of the first and second laws of thermodynamics. An effective convective mixing parameter is defined to reflect the interplay between the radial turbulence and local thermal gradients. The best enhancement technique yields 46% larger effective convective mixing with 26% lower turbulent kinetic energy compared to the least efficient case. The analysis shows that high heat transfer enhancement is promoted by inducing strong radial turbulent fluctuations in high-temperature-gradient regions while keeping other regions undisturbed. • Heat transfer enhancement via surface textures is studied via large eddy simulation. • Inward ellipsoids yield 22% higher heat transfer rate and 41% larger pressure drop. • The process driving heat transfer enhancement is explained via total energy budgets. • Near-wall radial fluctuations contribute the most towards enhancing heat transfer. • Axial vortices yield the best heat transfer enhancement and low entropy generation.

Pengaruh Jumlah Lilitan Groundstrap Pada Kabel Busi Terhadap Daya Dan Torsi Pada Sepeda Motor Supra 125

installation of Groundstrap on spark plug wires as grounding spark plug wires so that the fire voltage from the coil will focus on the spark plugs. The increase in power and torque occurs because the groundstrap is a type of Ignition Booster whose function is to stabilize the electric current produced by the coil so that the spark plugs can be bigger and more stable, remove stray frequencies or indeterminate voltages from the coil, focus and narrow the current, so that it becomes a firing point towards the spark plug for use as a combustion flame. A steady current produces a good fire, so that the combustion explosion is complete. The method used in this study is the experimental method (direct trial) by making a Groundstrap circuit to determine power and torque in a motorcycle gasoline engine using a Dynotest tool for adding Groundstrap to spark plug wires. In this study using copper wire with a diameter of 0.6 mm and there were 3 variables for the number of turns of the groundstrap wire, namely 60 turns, 90 turns, and 120 turns. In 2008 there was an increase in general, the maximum power and torque yields for standard conditions were 8.3 HP and 8.79 NM, the test on winding 120 experienced the most significant increase of 1.7 HP from standard conditions to 10.0 HP and the torque reaches 3.95 NM from standard conditions to 12.74 NM
 Keywords: Groundstrap, Copper Wire Coil, Power and Torque

The Effect of Magnetic Field Exposure on The Growth of Green and Red Spinach Plants

A magnetic field is defined as the space around a magnet that is still experiencing a magnetic force. As the electric force, the magnetic force is driven by something, namely a magnetic field. A moving charge creates a magnetic field which in turn exerts a force on another moving charge. This study aims to determine the effect of magnetic fields exposure on the growth of spinach plants. The increase in demand for spinach in Indonesia has not been matched by the availability of sufficient spinach, one of the reasons for the insufficient availability of spinach is the decrease in fertile land for agriculture. This causes the ability to produce spinach planted in the ground also decreases. This study uses materials that are easily obtained, the method used in this research is quantitative research with a true experimental design, in the form of magnetic field exposure on the growth rate of spinach plants. The magnetic field used is produced from the coils of copper wire with the number of 5, 20, 35, 50 and 0 widing, with the duration of exposure was 30 minutes every day for 7 days. Magnetic fields in water exposed whare soaking spinach seeds rested which increases the permeability of the seed film, activates calcium ions, and inhibits the growth of microorganisms in water that are harmful to seed germination and plant growth. From the results of this study indicate that the use of copper wire with the number of widing is still not optimally used.

Study on mechanical properties of locked coil wire rope under and post fire

• Carry out the static tensile test of the locked coil wire rope under and after high temperature. • Obtain the mechanical properties and failure mode of locked coil wire rope under and post fire. • The reduction law of locked coil wire ropes under and post fire is obtained. • Compared with the existing research, the failure mechanism of cable is studied. • The prediction method of temperature dependent mechanical properties is proposed. As a new type of strand with excellent performance, a locked coil wire rope has been commonly used in all types of prestressed spatial structures. Owing to its unique section, it has a different temperature distribution, bearing mechanism, and failure mode from a traditional cable. In this study, static tensile tests of locked coil wire rope specimens were conducted under and after elevated-temperature treatments, and reduction laws of the mechanical properties of the strand were obtained. Based on the test results, a method for prediction of the mechanical properties of locked coil wire ropes under and after elevated-temperature exposure was developed. The research showed that the failure of a locked coil wire rope is ductile failure. Its ultimate strength begins to decrease when the heating temperature exceeds 200 °C. When the temperature reaches 400 °C, the strength of the strand is lower than 50 % of that at room temperature. The heat treatment process reduces the strength and ductility of the strand. When the heating temperature of a strand reaches 400 °C, it should be replaced in time after a fire. The research results provide a theoretical basis for fire resistance and post fire assessment of prestressed structures.

Electronic Tunability and Cancellation of Serial Losses in Wire Coils.

This work presents a novel methodology to adjust the inductance of real coils (electronically) and to cancel out serial losses (up to tens or even hundreds of Ohms in practice) electronically. This is important in various fields of electromagnetic sensors (inductive sensors), energy harvesting, measurement and especially in the instrumentation of various devices. State-of-the-art methods do not solve the problem of cancellation of real serial resistance, which is the most important parasitic feature in low- and middle-frequency bands. In this case, the employment of serial negative resistance is not possible due to stability issues. To solve this issue, two solutions allowing the cancellation of serial resistance by the value of the passive element and an electronically adjustable parameter are introduced. The operational ranges are between 0.1 and 1 mH and 0.1 and 10 mH, valid in bandwidths from hundreds of Hz up to hundreds of kHz. The proposed concepts are experimentally tested in two applications: an electronically tunable oscillator of LC type and an electronically tunable band-pass RLC filter. The presented methodology offers significant improvements in the process of circuit design employing inductors and can be beneficially used for on-chip design, where serial resistance issues can be very significant.

Experimental study of utilizing springs on absorber plate of solar air heaters: Subjected to axial-flow and cross-flow

An experimental investigation is carried out to analyze hydraulic and thermal characteristics of a solar air heater when its absorber plate is enhanced with different springs. This analysis is conducted for relevant levels of geometric parameters, such as coil diameter (dc = 5, 10, 15 mm), wire diameter (dw = 0.5, 1.0, 1.5 mm), and coil pitch (pc = 2.5, 5.0, 7.5 mm). The results clarify that installing springs on the absorber plate has a great impact on solar air heaters’ performance. It is found that the effects of geometric parameters variations in the cross-flow pattern are higher than the axial-flow pattern. The Nusselt number enhancements and friction factor augmentations are in the ranges of 3.11–4.76 and 5.01–18.81 for the axial-flow pattern and 3.12–5.59 and 7.51–28.39 for the cross-flow pattern. In the axial-flow pattern, the best hydrothermal performance is achieved at the lowest level of the geometric parameters, while in the cross-flow pattern, an optimal level is found for all geometric parameters. New correlations are developed to predict the present experimental data. The comparative study discloses that utilizing springs inside solar air heaters results in noticeable heat transfer enhancement with moderate friction augmentations compared to other techniques.

Ignition of thermally-thick blunt body PMMA samples using a heated wire

Ignition limits and ignition delay times of thermally-thick polymethyl methacrylate (PMMA) spheres (4-cm diameter) and cylinders (5.08-cm diameter) are investigated by placing an electrically-heated wire coil beneath the sample in a slow forced flow. The wire serves as both a heater for the solid sample and a gas-phase hot spot to ignite the oxidizer-fuel vapor mixture. In the experiments, the wire's electrical current and power-on time, its distance from the sample surface, the forced flow velocity, oxygen percentage, and pressure are systematically varied. Ignition limits as a function of the oxygen percentage, pressure, and igniter current are determined. Two ignition delay times are determined: igniter-assisted ignition and self-sustained ignition. These critical times are also functions of the degree of heat-up of the sample interior. Solid temperature profiles are measured using embedded thermocouples to determine the sub-surface temperature gradients at the moment of ignition. The heat transfer modes from the igniter to the solid sample are numerically investigated during the pre-pyrolysis heat-up period. At the forward stagnation-point region where ignition occurs, radiation is greater than convection and accounts for approximately 60% of the total heat input. This is consistent with the experimental findings on ignition delay times and heat flux measurements.

Investigating thermal performance of combined use of SiO2-water nanofluid and newly designed conical wire inserts

BackgroundThe combined use of augmentation methods plays a significant role to enhance the thermohydraulic performance of thermal systems. This experimental study explores the thermohydraulic performance of a heat exchanger tube with the combined use of SiO2-water nanofluids and newly designed conical wire inserts. MethodsIn this study, a new wire coil insert with different properties from those previously proposed was created. The newly designed inserts were placed in a tube at five distances ranging from 0 to 33.6 mm and SiO2-water nanofluids were used at four volume concentrations (0.5–1.25%). The two step method was used to prepare nanofluids and the experiments were conducted in turbulent flow. Significant findings: The highest heat transfer performance was obtained in the conical wire inserts with pitch ratio of 0, and the least friction loss was obtained in the conical wire inserts with pitch ratio of 4. The best Performance Evaluation criteria was 1.75 at Reynolds number of 3338 and volume concentration of 1.25% for conical wire inserts with pitch ratio of 0. Moreover, the use of nanofluids provided a remarkable heat transfer rate with increased Reynolds number at high volume concentrations, whereas nanofluids at low volume concentrations slightly affected the heat transfer rate and pressure drop. The combination of two techniques presented a promising option for improving the hydrothermal qualities of the heat exchanger.

A Concise Analytical Formula of Mutual Inductance for Circular Rogowski Coil Revealing Spatial Distribution Characteristics of Mutual Inductance Deviation

Mutual inductance between primary wire and circular Rogowski coil varies with the position of primary conductor, the deviation of mutual inductance referred to center of circle causes the measurement error. Usually, the mutual inductance of Rogowski coil can be calculated by the summation of each turn of coil, however the spatial distribution characteristics of mutual inductance deviation has not been revealed. A concise analytical formula of mutual inductance is derived based on the summation form and verified by experiment in this paper, which leads to three characteristics of mutual inductance deviation. The first is the mapping relation of mutual inductance deviation between inside and outside Rogowski coil which established connection between positional accuracy and anti-interference ability. The second is the zero deviation line of mutual inductance deviation given by simple equation, which describes the position of primary wire where the measurement error vanishes. The third is approximate function on turns number, inner and outer radius of Rogowski coil and measurement error, which is easy to calculate and simplifies the design progress of Rogowski coil. Furthermore the formula and characteristics of mutual inductance can be generalized from uniform Rogowski coil and perpendicular primary wire to discontinuous PCB RC, primary conductor with cross section, and inclined primary wire. The mapping relation, zero deviation line and improved formula of mutual inductance deviation are discussed.

Exergetic Performance Analysis of Energy Storage Unit Fitted With Wire Coil Inserts

Abstract In a sensible storage system, energy is stored based on the distribution of energy and exergy at the specified conditions. It is believed that the least temperature gradient leads to a higher exergy availability and lower entropy generation in a storage system. An energy storage unit with multiple passages fitted with wire coil inserts is evaluated in the present work by assessing the exergy stored and the entropy generation number for heat transfer fluid (HTF) inlet temperature range of 45–75 °C and HTF flowrate of 0.022–0.029 kg/s. The wire coil inserts have a (p/d) ratio in the range of 0.25–0.75. The maximum exergy storage rate in the energy storage unit is found to be 55.43 W corresponding to an energy storage unit having wire coil insert (p/d = 0.25) at the HTF inlet temperature of 75 °C and HTF flowrate of 0.029 kg/s. Entropy generation number of the system with wire coil inserts (p/d = 0.5), compared to smooth HTF passage, is found to be 42.32% at HTF flowrate and inlet temperature of 0.026 kg/s and 45 °C, respectively.

Thermal Aging Study of an Anodized Aluminum Strip Wire for Winding and High Temperature Use

Electrical machines are commonly used in industries and transport and are manufactured with enameled wire coils with polymer insulation. In extreme conditions, as in aeronautics and aerospace, where temperatures exceed 280 °C, the organic insulation deteriorates and it is necessary to find another way to insulate winding wires, in order to ensure a longer life duration of the insulation system and a better operating reliability of electric motors in these environments. Ceramics are more resistant to high temperatures than polymers and the proposed study focuses on the temperature dependence of the dielectric properties of anodized aluminum strips for use in high-temperature electrical machine windings. Different dielectric parameters are measured during thermal constraint. The purpose is to determine the temperature index of the anodized strip and propose a thermal stress life model.

Endovascular Biopsy for Detection of Somatic Mosaicism in Human Fusiform Cerebral Aneurysms

Endovascular Biopsy for Detection of Somatic Mosaicism in Human Fusiform Cerebral Aneurysms

Thermal performance of microencapsulated phase change material slurry in helical coils with reversed loops and wire coil inserts

ABSTRACT In this study, the flow and heat transfer characteristics of microencapsulated phase change material (MPCM) slurry were experimentally investigated using a newly designed helical coil heat transfer device. The conventional helical coil has been structurally modified with passive enhancement features aiming to further promote fluid mixing. Specifically, 360° plastic tubing with or without wire coil inserts was added after each 180° of the main helical loop to enhance fluid mixing and improve the overall thermal performance of the device. Pressure drop and heat transfer experiments with MPCM slurry were conducted under turbulent flow and constant heat flux conditions. A new friction factor and Nusselt number correlations for MPCM slurry in helical coils with reversed loops and wire coil inserts are proposed. Experimental results show that the structural modifications did enhance the heat transfer performance of MPCM slurry. The experimental results revealed that the phase change process of MPCM considerably enhanced the heat transfer rate of MPCM slurry. Furthermore, the use of reversed loops and wire coil inserts led to better fluid mixing within the coil, resulting in improved convective heat transfer of the MPCM slurry.