Barrel heating with inductive coils in an injection molding machine

2019 ◽  
Vol 39 (10) ◽  
pp. 934-943
Author(s):  
Shih-Chih Nian ◽  
Gao-Hao Yeh ◽  
Ming-Shyan Huang
Keyword(s):  
Magnetic Field ◽  
Injection Molding ◽  
Heating Rate ◽  
Inductive Heating ◽  
Energy Rate ◽  
Heating Performance ◽  
Time Required ◽  
Spiral Grooves ◽  
The Magnetic Field ◽  
Inductive Coils

Abstract Traditional injection molding machines use resistance heating (RH) bands to heat the barrel. However, RH has a low energy rate; thus, the time required to reach the target temperature is rather long. Consequently, the use of inductive techniques, with a faster heating rate and improved energy rate, has attracted growing interest in recent years. However, an inappropriate design of the inductive coils and plasticization barrel may result in a strong repulsive magnetic field between neighboring coils and a corresponding reduction in the heating performance. Thus, developing an appropriate inductive heating design is essential in improving the barrel heating performance. The present study therefore performed a simulation and experimental investigation into the magnetic field and temperature distribution for different barrel geometries and coil current designs. The simulation results showed that the application of spiral grooves to the barrel improved both the heating rate and the temperature uniformity (TU) and effectively solved the proximity effect. The results indicated that the application of induction heating together with a novel grooved barrel design yields an effective improvement in both the thermal efficiency and the TU compared to that achieved using the traditional RH method with a single- or double-section barrel.

scholarly journals Magnetic nulls in interacting dipolar fields

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Todd Elder ◽  
Allen H. Boozer
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Magnetic Flux Tube ◽  
Electron Inertia ◽  
Characteristic Spatial Scale ◽  
Field Lines ◽  
Dipolar Fields ◽  
Time Required ◽  
Magnetic Null ◽  
The Magnetic Field

The prominence of nulls in reconnection theory is due to the expected singular current density and the indeterminacy of field lines at a magnetic null. Electron inertia changes the implications of both features. Magnetic field lines are distinguishable only when their distance of closest approach exceeds a distance $\varDelta _d$ . Electron inertia ensures $\varDelta _d\gtrsim c/\omega _{pe}$ . The lines that lie within a magnetic flux tube of radius $\varDelta _d$ at the place where the field strength $B$ is strongest are fundamentally indistinguishable. If the tube, somewhere along its length, encloses a point where $B=0$ vanishes, then distinguishable lines come no closer to the null than $\approx (a^2c/\omega _{pe})^{1/3}$ , where $a$ is a characteristic spatial scale of the magnetic field. The behaviour of the magnetic field lines in the presence of nulls is studied for a dipole embedded in a spatially constant magnetic field. In addition to the implications of distinguishability, a constraint on the current density at a null is obtained, and the time required for thin current sheets to arise is derived.

scholarly journals Principal Component Gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Principal Component ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
Time Required ◽  
First Time ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and time required to build a spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removal of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program and allowing for shorter boom length. The proposed algorithm is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean geostationary satellite GeoKompsat-2A (GK2A) which uses for the first time a multi-sensor configuration for onboard data cleaning. The successful elimination of disturbances originating from several sources validates the proposed cleaning technique.

scholarly journals Stochastic proton heating by kinetic-Alfvén-wave turbulence in moderately high- plasmas

2018 ◽  
Vol 84 (6) ◽  
Author(s):  
Ian W. Hoppock ◽  
Benjamin D. G. Chandran ◽  
Kristopher G. Klein ◽  
Alfred Mallet ◽  
Daniel Verscharen
Keyword(s):  
Magnetic Field ◽  
Heating Rate ◽  
Electrostatic Potential ◽  
Alfven Wave ◽  
Average Magnetic Moment ◽  
Kinetic Alfvén Wave ◽  
Stochastic Heating ◽  
Kinetic Alfven Wave ◽  
Time Variations ◽  
The Magnetic Field

Stochastic heating refers to an increase in the average magnetic moment of charged particles interacting with electromagnetic fluctuations whose frequencies are smaller than the particles’ cyclotron frequencies. This type of heating arises when the amplitude of the gyroscale fluctuations exceeds a certain threshold, causing particle orbits in the plane perpendicular to the magnetic field to become stochastic rather than nearly periodic. We consider the stochastic heating of protons by Alfvén-wave (AW) and kinetic-Alfvén-wave (KAW) turbulence, which may make an important contribution to the heating of the solar wind. Using phenomenological arguments, we derive the stochastic-proton-heating rate in plasmas in which $\unicode[STIX]{x1D6FD}_{\text{p}}\sim 1$–30, where $\unicode[STIX]{x1D6FD}_{\text{p}}$ is the ratio of the proton pressure to the magnetic pressure. (We do not consider the $\unicode[STIX]{x1D6FD}_{\text{p}}\gtrsim 30$ regime, in which KAWs at the proton gyroscale become non-propagating.) We test our formula for the stochastic-heating rate by numerically tracking test-particle protons interacting with a spectrum of randomly phased AWs and KAWs. Previous studies have demonstrated that at $\unicode[STIX]{x1D6FD}_{\text{p}}\lesssim 1$, particles are energized primarily by time variations in the electrostatic potential and thermal-proton gyro-orbits are stochasticized primarily by gyroscale fluctuations in the electrostatic potential. In contrast, at $\unicode[STIX]{x1D6FD}_{\text{p}}\gtrsim 1$, particles are energized primarily by the solenoidal component of the electric field and thermal-proton gyro-orbits are stochasticized primarily by gyroscale fluctuations in the magnetic field.

Improved the Performance of Focusing Deep Hyperthermia Inductive Heating for Breast Cancer Treatment by Using Ferro-Fluid with Magnetic Shielding System

2013 ◽  
Vol 325-326 ◽  
pp. 353-358 ◽  
Author(s):  
Thosdeekoraphat Thanaset ◽  
Santalunai Samran ◽  
Thongsopa Chanchai
Keyword(s):  
Magnetic Field ◽  
Field Intensity ◽  
Magnetic Fluid ◽  
Magnetic Field Intensity ◽  
Magnetic Shielding ◽  
Inductive Heating ◽  
Surrounding Healthy Tissue ◽  
The Magnetic Field ◽  
Shielding System ◽  
Deep Hyperthermia

The performance improved of focusing deep hyperthermia inductive heating for breast cancer treatment using magnetic fluid nanoparticles with magnetic shielding system has been presented in the paper and the results are discussed. It is a technique challenge in hyperthermia therapy is to control locally heat the tumor region up to an appropriate temperature to destroy cancerous cells, without damaging the surrounding healthy tissue by using magnetic fluid nanoparticles and cylindrical metal shielding with aperture. We show that the magnetic field intensity can be controlled by changing the aperture size to suitable. In addition, the position of the heating can be controlled very well with the magnetic fluid together with shielding system. In the simulation, the inductive applicator is a ferrite core with diameter of 7 cm and excited by 4 MHz signal. Results have shown that the temperature increments depend on the magnetic fluid nanoparticles. In addition, the magnetic field intensity without damaging the surrounding healthy tissue when used magnetic shielded system. These results demonstrate that it is possible to achieve higher temperatures and to focus magnetic field intensity where the nanoparticles and magnetic shielding system are used.

On the Heating of a Pinch

1970 ◽  
Vol 25 (12) ◽  
pp. 1803-1807
Author(s):  
R. Mewe
Keyword(s):  
Magnetic Field ◽  
Heating Rate ◽  
Initial Rate ◽  
Final Value ◽  
Capacitor Banks ◽  
Theta Pinch ◽  
The Magnetic Field ◽  
Compression Temperature

Abstract The compression temperature of a theta pinch is calculated as a function of the circuit para-meters and the final /?-value of the plasma. One of the results is that the temperature, T, at the peak magnetic field, B, scales of (B B) t/s , where B is the initial rate of rise of the magnetic field. A possibility of combining two capacitor banks to increase the implosion heating rate is discussed.

Effect of Magnetic Field on the Fiber Orientation during the Filling Process in Injection Molding, Part 1: Simulation and Mold Design

2018 ◽  
Vol 936 ◽  
pp. 126-135
Author(s):  
Chen Yuan Chung ◽  
Shia Chung Chen ◽  
Kuan Ju Lin
Keyword(s):  
Magnetic Field ◽  
Injection Molding ◽  
Carbon Fibers ◽  
Fiber Orientation ◽  
Conductive Polymer ◽  
Polymer Composite Material ◽  
Magnetic Flux Density ◽  
Filling Process ◽  
Coated Carbon ◽  
The Magnetic Field

Conductive polymer composite material is increasingly applied in a variety of fields, and its related processing technology has been a focus of research and development. Regarding magnetic fiber, because the orientation and distribution of the fiber affect the electrical and mechanical properties of products, the control of fiber orientation and distribution has been regarded as a key technology. This study used magnetic-assisted injection molding to control the orientation of magnetic fibers during the melt-polymer filling process. A special mold containing a magnetic apparatus was simulated and designed. Its material and thickness of various spacing blocks as well as the optimal layout of magnets in the mold were determined. An actual mold with the same magnet layout was then manufactured accordingly, and the measured magnetic flux density was compared with simulated results. This study also examined the coupled effect of magnetic and flow fields on the orientation of nickel-coated carbon fibers, calculating the magnetic moment produced due to the influence of the magnetic field on the fibers when melt polymer flowed through various positions in the cavity during the filling process. The flow trajectories of the fibers, which were affected by the magnetic field, were also predicted.

scholarly journals Maximum-variance gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Vol 9 (2) ◽  
pp. 451-469
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Maximum Variance ◽  
Service Oriented ◽  
Corrected Data ◽  
Sensor Configuration ◽  
Time Required ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using spaceborne instruments requires a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and the time required to build a spacecraft. Here we present an alternative sensor configuration and a technique allowing for removal of the spacecraft-generated AC disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness programme and allowing for shorter boom length. The final expression of the corrected data takes the form of a linear combination of the measurements from all sensors, allowing for simple onboard software implementation. The proposed technique is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) on board the Korean geostationary satellite GeoKompsat-2A (GK2A). In contrast to other missions where multi-sensor measurements were used to clean the data on the ground, the SOSMAG instrument performs the cleaning on board and transmits the corrected data in real time, as needed by space weather applications. The successful elimination of the AC disturbances originating from several sources validates the proposed cleaning technique.

Magnetorheological Fluid Behavior Under Constant Shear Rates and High Magnetic Fields Over Long Time Periods

2005 ◽  
Vol 128 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Constantin Ciocanel ◽  
Kevin Molyet ◽  
Hideki Yamamoto ◽  
Sheila L. Vieira ◽  
Nagi G. Naganathan
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Shear Rate ◽  
Shear Rates ◽  
Fluid Behavior ◽  
Constant Shear ◽  
Long Time ◽  
Time Required ◽  
And Behavior ◽  
The Magnetic Field

This paper presents a new magnetorheological (MR) cell design along with a study of the magnetic field, shear rate, and time/shear strain influences on the properties and behavior of a MR fluid tested for long periods of time. The MR cell was designed to adapt a commercially available rheometer to measure the rheological properties of the fluid. Overall characteristics of the designed MR cell output capability are provided. Constant shear rate tests, two hours in duration, have been performed at shear rates between 0.1l∕s and 200l∕s under magnetic field intensities up to 0.4T. The rheological measurements indicated that over time the fluid’s shear stress magnitude decreases until it reaches a steady state. The time required to reach the steady state depends on both the magnetic field strength and the shear rate. The higher the field and the smaller the shear rate the shorter the time for the steady state to be reached.

Cranial surgery with an expanded compact intraoperative magnetic resonance imager

2006 ◽  
Vol 104 (4) ◽  
pp. 611-617 ◽  
Author(s):  
Michael Schulder ◽  
Sussan Salas ◽  
Michael Brimacombe ◽  
Peter Fine ◽  
Jeffrey Catrambone ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
First Generation ◽  
Additional Time ◽  
Mean Error ◽  
Low Field ◽  
Skull Base Lesions ◽  
Time Required ◽  
Navigational Tool ◽  
The Magnetic Field

✓In this article the authors report the implementation of an expanded compact intraoperative magnetic resonance (iMR) imager that is designed to overcome significant limitations of an earlier unit. The PoleStar N20 iMR imager has a stronger magnetic field than its predecessor (0.15 tesla compared with 0.12 tesla), a wider gap between magnet poles, and an ergonomically improved gantry design. The additional time needed in the operating room (OR) for use of iMR imaging and the number of sessions per patient were recorded. Stereotactic accuracy of the integrated navigational tool was assessed using a water-covered phantom. Of the 55 patients who have undergone surgery in the PoleStar N20 device, diagnoses included glioma in 13, meningioma in 12, pituitary adenoma in nine, other skull base lesions in seven, and miscellaneous other diagnoses. The extra time required for use of the system averaged 1.1 hours (range 0.5–2 hours). Imaging sessions averaged 2.3 per surgery (range one–six sessions). Measurement of stereotactic accuracy revealed that T1-weighted images were the most accurate. Thinner slices yielded measurably greater accuracy, although this was of questionable clinical significance (all sequences ≤ 4 mm had a mean error of ≤ 1.8 mm). The position of the phantom in the center compared with the periphery of the magnetic field did not affect accuracy (mean error 0.9 mm for each). The PoleStar N20 appears to make intraoperative neuroimaging with a low-field-strength magnet much more practical than it was with the first-generation device. Greater ease of positioning resulted in a decrease in added time in the OR and encouraged a larger number of imaging sessions.

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