Current Heating Method Research Articles

A Review on Parameters Affecting the Choice of Alternative (Non-Chemical) Weed Control Methods

Chemical using as a weed control method is the most preferred method in weed control because they are easily accessible, easily applicable and inexpensive. But, with the new environment-friendly regulations, the importance of non-chemical methods has increased all over the world. In addition, organic farm and non-chemical agricultural methods are gaining importance with increasing social environment and health awareness. Non-chemical methods, called, "alternative methods” have been one of the most popular research subjects in recent years. The physical removal or killing of weeds is usually done by hand or by means designed tools for this task, which varies from country to country. The most known modern non-chemical weed control methods are; electric current, microwave heating, superheated steam, infrared using, pneumatic system, freeze-drying, laser cutting, and fresnel lens systems. The most popular of these methods are; electric current method and microwave heating. In electric current and microwave heating methods, there are no chemical residues in soil and plants after application. It has been shown in the studies that, the microwave weed control method can destroy weeds and seeds when appropriate frequency, sufficient time and required power level are selected. Therefore, in the selection of non-chemical weed control methods, some important parameters of plant and soil should be known. The electrical and dielectric properties of plants and soil such as, electrical resistance (R), impedance (Z), dielectric constant (ε’), loss factor (ε’’), the permittivity (permeability ( and conductivity (σ) should be known especially in microwave and electric current methods. The other parameters like the age, height and density of the plant is an issue to be considered in all control methods. But, the moisture content of soil and plant may not be taken into consideration in hot water and steam applications. For the freeze-drying method, the moisture and water content of the plant and soil must also be taken into account.

Review on Parameters Affecting the Choice of Alternative (Non-Chemical) Weed Control Methods

Chemical using as a weed control method is the most preferred method in weed control because they are easily accessible, easily applicable and inexpensive. But, with the new environment-friendly regulations, the importance of non-chemical methods has increased all over the world. In addition, organic farm and non-chemical agricultural methods are gaining importance with increasing social environment and health awareness. Non-chemical methods, called, "alternative methods” have been one of the most popular research subjects in recent years. The physical removal or killing of weeds is usually done by hand or by means designed tools for this task, which varies from country to country. The most known modern non-chemical weed control methods are; electric current, microwave heating, superheated steam, infrared using, pneumatic system, freeze-drying, laser cutting, and fresnel lens systems. The most popular of these methods are; electric current method and microwave heating. In electric current and microwave heating methods, there are no chemical residues in soil and plants after application. It has been shown in the studies that, the microwave weed control method can destroy weeds and seeds when appropriate frequency, sufficient time and required power level are selected. Therefore, in the selection of non-chemical weed control methods, some important parameters of plant and soil should be known. The electrical and dielectric properties of plants and soil such as, electrical resistance (R), impedance (Z), dielectric constant (?’), loss factor (?’’), the permittivity (permeability ( and conductivity (?) should be known especially in microwave and electric current methods. The other parameters like the age, height and density of the plant is an issue to be considered in all control methods. But, the moisture content of soil and plant may not be taken into consideration in hot water and steam applications. For the freeze-drying method, the moisture and water content of the plant and soil must also be taken into account.

Effect of compaction pressure of green body and heating current on photoluminescence property of ZnO crystal grown by electric current heating method

In this study, we reported the effect of applied compaction pressure on green body and electric current heating on ceramic bar on the ZnO crystal growth and its photoluminescence characteristic. Crystals grown on ZnO bar sintered by 1100 °C were mostly on (1 0 1) orientation. Sample with 3.0 ton and 3.0 A for applied pressure and current, respectively revealed the shortest photoluminescence (PL) wavelength of 409.5 nm with highest emission energy of 3.03 eV.

Reduction of Iron Loss on Laminated Ultrathin Electrical Steel Sheet Cores by Secondary Current Heating Method

This paper presents the newly proposed heating method names as “Secondary Current Heating Method” to reduce the iron loss on laminated electrical steel sheet cores for high efficiency electrical motors. It is well known that the magnetic properties of electrical steel sheets, which are used for electrical motor cores, are deteriorated by the residual stress during manufacturing the electrical motors, and then the iron loss of the laminated electrical steel sheet cores of the electrical motors increases inevitably. The newly proposed Secondary Current Heating Method can improve the magnetic properties on laminated electrical steel sheet cores and reduce the iron loss of them in the very short time in comparison with conventional methods. In this paper, the electromagnetic and heating characteristics of the specimens by proposed method were confirmed, and then it was applied into the laminated ultrathin electrical steel sheet cores for high speed motors to reduce iron loss.

Reduction of Iron Loss on Laminated Electrical Steel Sheet Cores by Means of Secondary Current Heating Method

This paper presents the newly proposed heating method named “secondary current heating method” to reduce the iron loss on laminated electrical steel sheet cores for high-efficiency electrical motors. It is well known that the magnetic properties of electrical steel sheets, which are used for electrical motor cores, are deteriorated by the residual stress during manufacturing of the electrical motors, and then the iron loss of the laminated electrical steel sheet cores of the electrical motors increases inevitably. The newly proposed secondary current heating method can improve the magnetic properties on laminated electrical steel sheet cores and reduce the iron loss of them in the very short time in comparison with conventional methods. In this paper, the electromagnetic and heating characteristics of the specimens by the proposed method were confirmed, and then it was applied into the laminated cores to reduce iron loss.

Two-layer Thermal Model and Experiment of Cylindrical Lithium-ion Battery for Sinusoidal Alternate Current Heating

The poor battery discharging performance and capacity, operated at low temperature, pose a technical barrier limiting their use in electric vehicles. In recent years there has been an increasing interest in heating battery in order to improve its low temperature performance. In this paper, a sinusoidal alternate current (AC) heating method is proposed to heat the battery. The battery is heated fast and uniformly, due to a large amount of heat generated at the inside of battery when sinusoidal alternate current is transited in a battery. Furthermore, a two-layer thermal model is established to simulate the heating method, where genetic algorithm is used for model parameter identification. At last some sinusoidal alternate current heating experiments were conducted to show the model accurately simulate real heat generation. The proposed heating strategy is of great potential for rapidly improving operating performance of electric vehicles in cold weather.

Analysis of Short Circuit Fault for 4.6GHz/6MW LHCD High Voltage Power Supply

4.6GHz/6MW Lower Hybrid Current Drive (LHCD) is one of plasma current heating methods for Experimental Advanced Superconducting Tokamak (EAST). High Voltage Power Supply (HVPS) is the power supply subsystem of 4.6GHz/6MW LHCD system, which was designed, built and accepted successfully by Chinese National Development and Reform Commission in 2015. Then the new system has been in use for the 2015 EAST campaign. This paper presents the structure of 4.6GHz/6MW LHCD-HVPS and its transient operation state when its klystron load has short circuit fault. In order to protect the klystron and HVPS itself, the short-circuit fault and its transient process are analyzed and calculated in detail. And a three-electrode gas switch has been built to eliminate the short-circuit fault in microseconds. In addition, the effectiveness of the three-electrode gas switch has been verified by simulation and experiment result. The HVPS has been used in 4.6GHz/6MW LHCD system and it has good performance for the entire 2015 EAST campaign.

MOCVD-derived multilayer Gd0.5Y0.5Ba2Cu3O7−δ films based on a novel heating method

Multilayer Gd0.5Y0.5Ba2Cu3O7−δ (GdYBCO) films have been deposited by the metal organic chemical vapor deposition process on LaMnO3/epitaxial MgO/ion beam assisted deposition (IBAD)-MgO/solution deposition planarization-Y2O3-buffered Hastelloy tapes. The buffered tapes were heated by the Joule effect after applying a heating current (Ih) through the Hastelloy metal substrates. For this kind of current heating method, the heating energy is transmitted from the Hastelloy metal substrate to the oxide buffer layers, thereby the surface temperature of the tape will decline with an increase in the thickness of the deposited GdYBCO film if the heating current is unchanged. Therefore, the multilayer GdYBCO film structure where Ih was adjusted for each layer was adopted to make sure that the surface temperature was always high enough to deposit purely c-axis oriented GdYBCO films. With this method, four-layer 1000 nm thick GdYBCO films were successfully prepared and the critical current (Ic) reached 328 A cm−1 width (77 K, 0 T), corresponding to the critical current density (Jc) of 3.28 MA cm−2 (77 K, 0 T).

An alternating current heating method for lithium-ion batteries from subzero temperatures

An alternating current (AC) heating method for lithium-ion batteries is proposed in the paper. Effects of current frequency, amplitudes and waveforms on the temperature evolution and battery performance degradation are respectively investigated. First, a thermal model is established to depict the heat generation rate and temperature status, whose parameters are calibrated from the AC impedance measurements under different current amplitudes and considering battery safe operating voltage limits. Further experiments with different current amplitudes, frequencies and waveforms on the 18650 batteries are conducted to validate the effectiveness of the AC heating. The experimental data recorded by appropriate measurement instrument are of great consistence with simulation results from the thermal model. At high frequency, the temperature rises prominently as the current increases, and high frequency serves as a good innovation to reduce the battery degradation. However, efficient temperature rise can be obtained from high impedance at low frequencies. Typically, 600 s is needed to heat up the battery from −24 °C to 7.79 °C with sinusoidal waveform and approximately from −24 °C to 25.6 °C with rectangular pulse waveform at 10A and 30 Hz. The model and experiments presented have shown potential value in battery thermal management studies for electric vehicle (EV)/hybrid electric vehicle (HEV) applications at subzero temperatures. Copyright © 2016 John Wiley & Sons, Ltd.

Investigation of the high-temperature properties of zirconium nitride by impulse current heating method

The zirconium nitride specimens were obtained as a thin (2.5 μm) layer deposited on the insulating K-8 glass substrates by the magnetron sputtering technique. The impulse current heating permitted reaching the nitride melting region in 5 μs. The current, the voltage, and the radiation at the wavelength of 856 nm were registered. The energy input (the enthalpy), E, the heat capacity, C p , the resistivity, ρ (referred to the initial specimen dimensions), and the temperature, T, were calculated. The results on the resistivity, the specific heat, and the melting temperature (2700 K) of the zirconium nitride under a high content of nitrogen (about 49 at %) and oxygen (about 11 at %) in the specimen were obtained. The limit temperature in the investigation was as high as 3400 K.

Influence of Stress-Relief Annealing on Magnetic Properties of Motor Cores Using Induced Current Heating Method

Influence of Stress-Relief Annealing on Magnetic Properties of Motor Cores Using Induced Current Heating Method

Rapid Bonding of Ti3SiC2 and Ti3AlC2 by Pulsed Electrical Current Heating

Inspired by pressure resistance welding of metallic materials, herein we describe how two MAX phases—Ti3SiC2 and Ti3AlC2—were successfully joined by a rapid electric current heating method in a pulsed electric current sintering furnace. No welding agent was employed and the total processing time was less than 6 min. When the bulk temperature of the joint couple exceeded 1070°C, good joints, with shear strength above 50 MPa, were achieved in both homo‐ and heterojunction joints.

The effect of tool heating arrangement on fibre material forming

In this paper, a new heating arrangement has been developed for improving the performance of paperboard forming process. Problem areas of current heating methods were identified by analyzing several forming moulds used for tray production in packaging industry. This analysis was used as basis for design process of the new and more advanced mould. The new process utilizes oil to distribute heat evenly in the mould resulting in reduced process parameter adjustment during production. The versatility of the improved design manifests in less variance in outer dimension of trays and reduced volume of rejects.

Effect of Repeated Thermal Shock on Mechanical Properties of ZrB2-SiC-BN Ceramic Composites

ZrB2-20 vol.% SiC-10 vol.% h-BN (particles) ceramic composites (ZSB) were fabricated by hot pressing under inert gas protected. ZSB samples with mean size 75 × 55 × 40 mm3 were heated using current heating method and then cooled down to low temperature by circulating water. ZSB samples repeatedly went through thermal shock with 10–50 times under various conditions, respectively. Diverse effects on residual strength of ZSB at different experiment conditions (temperatures, thermal shock times, and heating rates) were investigated. The test results indicated that the residual strength of specimen materials all reached the maximum while the temperature was 1600°C and thermal shock number was less than 50 times. Because ZSB samples could not stand the extremely serious hyperoxidation at very high temperature (1800°C), the residual strength of samples decreased sharply. At 1600°C, when the thermal shock times was 20, ZSB samples' residual strength reached the maximum, but it decreased to the lowest point while the thermal shock times was 30. So we argued that the sensitive thermal shock number was 30. Finally, we analyzed the influences on samples residual strength generated by different heating rates at the same temperature and thermal shock number; the results showed that when heating rate was equal to cooling rate, the residual strength of specimen materials reached the maximum.

Effect of catalytic pyrolysis conditions using pulse current heating method on pyrolysis products of wood biomass.

The influence of catalysts on the compositions of char and pyrolysis oil obtained by pyrolysis of wood biomass with pulse current heating was studied. The effects of catalysts on product compositions were analyzed using GC-MS and TEM. The compositions of some aromatic compounds changed noticeably when using a metal oxide species as the catalyst. The coexistence or dissolution of amorphous carbon and iron oxide was observed in char pyrolyzed at 800°C with Fe3O4. Pyrolysis oil compositions changed remarkably when formed in the presence of a catalyst compared to that obtained from the uncatalyzed pyrolysis of wood meal. We observed a tendency toward an increase in the ratio of polyaromatic hydrocarbons in the pyrolysis oil composition after catalytic pyrolysis at 800°C. Pyrolysis of biomass using pulse current heating and an adequate amount of catalyst is expected to yield a higher content of specific polyaromatic compounds.

Relationship between particle size and photochromic characteristics of tungsten oxide films prepared by electric current heating method using tungsten wire

Tungsten oxide films were deposited on glass substrates placed above tungsten wires heated by electric current in air. The film thickness in a region just above the wire (region A) was thinner than that in other region (region B). The observation using scanning electron microscope revealed that the films consisted of particles. The shapes of the particles were sphere in the region A while smaller octahedron shape was found in the region B. The amount of the particles in the region B was greater than that in A. The ratio of the number of small particles with a diameter ≤500nm to the total particle number in the region A increased with decreasing applied voltage during the electric current heating, whereas, in the region B, the size of particles was ≤500nm and had no applied voltage dependence. The films exhibited photochromism; the reflectance in the near-infrared region was decreased by the ultraviolet irradiation. In region A, the photochromic effects increased with decreasing applied voltage to the wire. On the other hand, in region B, the photochromic effects did not show the applied voltage dependence. Consequently, it was found that the obtained films showed positive correlation between photochromic effect and the ratio of the number of small particles (≤500nm) to the total particle number. The particles in region B are suitable for mass production of the photochromic material because the photochromic effect and the amount of particles in region B are greater than those in A.

Synthesis of Cubic Ni Nanoparticles by Electric Current Heating Method Using Ni Wire

Nickel wire was used as a starting material to fabricate Ni nanoparticles. A glass substrate was placed above the wire to deposit the particles. The wire was heated by applying a d. c. voltage in the range of 2.2 ~ 4.0 V in oxygen atmosphere until the wire broke. White deposits were observed on the substrate after the heating. The TEM observation revealed that the deposits consisted of cubic nanoparticles with the edge lengths of 2 ~ 200 nm. The size of the particle tended to decrease with decreasing voltage. The particles were covered with films of approximately 4 nm in thickness. After reducing in hydrogen at 250°C for 30 min, the thickness of the films on the cubic particles decreased and the XRD peak intensity attributed to NiO decreased. Consequently the particles were found to be cubic Ni nanoparticles covered with NiO thin films.

ZnO nanowire growth by electric current heating method: A study on the effect of substrate temperature

In this study, we report the growth of ZnO nanowire on quartz glass substrates with Au-catalyst assistance by electric current heating of ZnO ceramic bar. The effect of substrate temperature on the properties of ZnO nanostructures has been investigated systematically. Structural analysis indicates that the grown ZnO crystals belong to hexagonal phase with preferential growth along (002) orientation. Scanning electron microscopic studies reveal the aligned ZnO nanowires were grown at 800°C. The typical length and diameter of nanowires are in the uniform ranges of 4–20μm and 20–100nm, respectively, showing their high aspect ratio of about 1000. We have made an attempt to discuss about the change in ZnO nanostructures with different substrate temperatures and the possible mechanism for the growth of nanowires. Optical reflectance studies show the infrared reflectivity was controlled through the substrate temperature.

Thermoelectric Properties and Densification Behavior of SrTiO<sub>3</sub>/TiB<sub>2</sub> Composites

The establishment of rapid synthesis process at a low temperature of thermoelectric non-doped and Y-doped SrTiO3 was tried by using the polymerized complex process and the pulsed current heating method with addition of TiB2 powder. The TiB2 addition was quite effective for reduction in the electrical resistivity of the thermoelectric SrTiO3, and the power factor of the Sr0.9Y0.1TiO3/TiB2 composite was similar to that of the Sr0.9Y0.1TiO3 polycrystal synthesized by the conventional solid state reaction method. It was also found that the addition of TiB2 significantly reduced densification temperature during sintering. This rapid consolidation caused by TiB2 addition was available even when the composite powder was sintered by conventional hot pressing.

Effects of distance between tungsten wire and glass substrate on particle size and photochromic characteristic of tungsten oxide prepared by electric current heating method

Tungsten oxide films consisting of particles were prepared on the substrates placed at various distances from the tungsten wires heated by electric current. The shapes of the particles were sphere in an area on the substrate just above the wire while octahedral shape was found in other area. For the spherical particles, with increasing the distance, the mean particle diameter increased, reached its maximum value and gradually decreased. The particles in each area showed the photochromism especially in near-infrared region. The spherical particles with the smallest size exhibited a significant photochromic effect which could be controlled by changing the distance between the wire and the substrate.