Effect of Pulse Width and Dependence on Administration Energy on Increment of Fruit Body Yield in Log Cultivation of Pholiota Microspore by Pulsed High-Voltage Stimulation

2017 ◽  
Vol 137 (8) ◽  
pp. 510-511
Author(s):  
Hiroto Kanemitsu ◽  
Shinya Kawaguchi ◽  
Katsuyuki Takahashi ◽  
Koichi Takaki ◽  
Kyusuke Takahashi ◽  
...  
Keyword(s):  
High Voltage ◽  
Pulse Width ◽  
Fruit Body ◽  
Log Cultivation ◽  
Fruit Body Yield

Effect of pulse width on dynamic characteristics of high voltage IGBTs

2014 ◽  
Author(s):  
John F. Donlon ◽  
Eric R. Motto ◽  
Eugen Wiesner ◽  
Eugen Stumpf ◽  
Shinichi Iura ◽  
...  
Keyword(s):  
High Voltage ◽  
Dynamic Characteristics ◽  
Pulse Width

Spiral pulse generator with high voltage and μs long pulse width

2010 ◽  
Vol 22 (4) ◽  
pp. 787-790
Author(s):  
方进勇 Fang Jingyong ◽  
江伟华 Jiang Weihua ◽  
黄文华 Huang Wenhua
Keyword(s):  
High Voltage ◽  
Pulse Width ◽  
Pulse Generator ◽  
Long Pulse

Transient Two-Phase Flow Patterns by Application of a High Voltage Pulse Width Modulated Signal and the Effect on Condensation Heat Transfer

2010 ◽  
Author(s):  
K. Ng ◽  
C. Y. Ching ◽  
J. S. Cotton
Keyword(s):  
Heat Transfer ◽  
Flow Pattern ◽  
Electric Fields ◽  
High Voltage ◽  
Mass Flux ◽  
Pulse Width ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Pulse Width Modulated

The objectives of this study are (i) to determine the transient phase redistributions of a two-phase flow in a smooth horizontal annular channel by applying high voltage pulses to induce electric fields and (ii) to quantify the resultant changes in the condensation heat transfer. The experiments were performed using refrigerant R-134a flowing in a tube that was cooled on the outside by a counter-current flow of water. The electric fields are established by applying high voltage to a concentric rod electrode inside a grounded tube. The effect of the electrohydrodynamic (EHD) forces on the changes to the initial stratified/stratified wavy flow pattern was visualized using a high speed camera. The EHD effect results in the redistribution of the liquid-vapour phase within the channel and unique flow structures, such as twisted liquid cones and entrained droplets, are observed. These structures only appear during the initial application of EHD and are absent in the steady state flow pattern. Experiments were performed using a 8kV pulse width modulated (PWM) signal with duty cycles ranging from 0–100% to evaluate the heat transfer and pressure drop characteristics of the transient EHD flow patterns. The resultant heat transfer increased with the duty cycle to approximately 2.7-fold at a low mass flux (45–55kg/m2s) and 1.2-fold at a high mass flux (110kg/m2s). The enhancement was higher as the pulse width was increased.

scholarly journals Relationship between Carbohydrate Content and Fruit Body Yield on Sawdust-based Media of Auricularia polytricha

2011 ◽  
Vol 57 (1) ◽  
pp. 8-13
Author(s):  
Shoji Ohga ◽  
Ryouhei Miyamoto ◽  
Joo-Young Cha ◽  
Geon-Suk Seo
Keyword(s):  
Fruit Body ◽  
Carbohydrate Content ◽  
Auricularia Polytricha ◽  
Fruit Body Yield

Method and Mechanism of Regulating Rheological Properties of Water-Based Drilling Fluid by High-Frequency and High-Voltage Alternating Current Electric Field

SPE Journal ◽  
2020 ◽  
Vol 25 (05) ◽  
pp. 2220-2233
Author(s):  
Weian Huang ◽  
Ming Lei ◽  
Jingwen Wang ◽  
Kaihe Lv ◽  
Lin Jiang ◽  
...  
Keyword(s):  
Electric Field ◽  
Rheological Properties ◽  
High Voltage ◽  
High Frequency ◽  
Pulse Width ◽  
Drilling Fluid ◽  
Width Ratio ◽  
Drilling Fluids ◽  
Water Based ◽  
Bentonite Suspension

Summary The rheology of drilling fluid is commonly regulated by chemical methods. In this work, a physical method of a high-frequency and high-voltage alternating current (AC) electric field to regulate the rheological properties of water-based drilling fluid is established. The effects of the electric field on the continuous phase and dispersed phase, as well as two kinds of water-based drilling fluids, were investigated, and the response relationship among rheological properties modeled by Bingham and Herschel-Bulkley (H-B) models and electric-field parameters was explored. Results showed that water conductivity increased when voltage reached 4 kV, whereas it was restored to the original state after 3 hours in the absence of an electric field, showing a memory effect. The effect was also observed on bentonite suspension, whose plastic viscosity increased with the aid of an electric field and decreased over time. Voltage showed the greatest effect on bentonite-suspension viscosity, followed by frequency and pulse-width ratio. Under the condition of voltage of 5 kV, frequency of 5 kHz, and pulse-width ratio of 80%, there was a maximum increase of 50% in viscosity. The addition of salts caused bentonite-suspension flocculation, and electric field reduced the consistency coefficient and relieved flocculation state. When polymers were incorporated in bentonite suspension, the electric field could decrease the adsorption amount between clay particles and polymeric additives such as amphoteric and acrylamide-based polymers. For two typical drilling fluids, the voltage of an introduced electric field was the main controlling factor to change the rheological properties; their plastic viscosity and consistency coefficient both started to increase when voltage reached 4 kV.

Designing of a High Voltage Power Supply for Electrospinning Apparatus Using a High Voltage Flyback Transformer (HVFBT)

2015 ◽  
Vol 771 ◽  
pp. 145-148 ◽  
Author(s):  
Muhammad Miftahul Munir ◽  
Dian Ahmad Hapidin ◽  
Khairurrijal
Keyword(s):  
High Voltage ◽  
Duty Cycle ◽  
Power Supply ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Experimental Results ◽  
High Voltage Power Supply ◽  
Electrospinning Technique ◽  
The World

Research on nanofiber materials is actively done around the world today. Various types of nanofibers have been synthesized using an electrospinning technique. The most important component when synthesizing nanofibers using the electrospinning technique is a DC high voltage power supply. Some requirements must be fulfilled by the high voltage power supply, i.e., it must be adjustable and its output voltage reaches tens of kilovolts. This paper discusses the design and development of a high voltage power supply using a diode-split transformer (DST)-type high voltage flyback transformer (HVFBT). The DST HVFBT was chosen because of its simplicity, compactness, inexpensiveness, and easiness of finding it. A pulse-width modulation (PWM) circuit with controlling frequency and duty cycle was fed to the DST HVFBT. The high voltage power supply was characterized by the frequency and duty cycle dependences of its output voltage. Experimental results showed that the frequency and duty cycle affect the output voltage. The output voltage could be set from 1 to 18 kV by changing the duty cycle. Therefore, the nanofibers could be synthesized by employing the developed high voltage power supply.

scholarly journals Analysis of Sinusoidal Pulse Width Modulation Parameter Settings in High Precission Closed Loop Full Bridge Bipolar Inverters for High Voltage High Frequency Generator

Teknik ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 55-61
Author(s):  
Abdul Syakur ◽  
Arifin Wibisono
Keyword(s):  
High Voltage ◽  
High Frequency ◽  
Pulse Width ◽  
Large Scale ◽  
Closed Loop ◽  
Pulse Width Modulation ◽  
Waste Treatment ◽  
Electrical Energy ◽  
Loop Control ◽  
Sinusoidal Pulse Width Modulation

The application of high voltage becomes more important and wider. High voltage is needed in the process of reducing air contaminants, waste treatment, sanitation, disinfecting microorganisms, testing for insulating high voltage equipment, and transmitting electrical energy. The problem of high voltage AC generation system is still in a large scale, static, not portable, and very expensive. This paper presents an analytical design of a high-voltage AC high-frequency based on power electronic. It is portable, less expensive, and eaasier to control the amplitudo and frequency. The application of the Full Bridge Bipolar Inverter topology with the Sinusoidal Pulse Width Modulation switching method provides variable sinusoidal AC voltage outputs (Vo) on its amplitude and frequency. The Tesla Coil Transformer amplifies the amplitude in accordance with the classification of the high voltage AC in the order of Kilo Volt. The Closed Loop control system in the Bipolar Inverter Full Bridge topology provides high accuracy results between the given setting values and the actual amplitude output and the expected high-frequency AC voltage. Analysis of the SPWM switching pattern parameter settings shows stability for several loading variations

scholarly journals COMPARISON OF METHODS FOR COMPENSATION FOR DAMAGE TO H-CELLS IN HIGH-VOLTAGE CASCADE FREQUENCY CONVERTERS

2021 ◽  
Vol 3 (55) ◽  
pp. 24-31
Author(s):  
V. Busher ◽  
◽  
O. Glazeva ◽  
Du Xin ◽  
◽  
...  
Keyword(s):  
High Voltage ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Comparison Of Methods ◽  
Space Vector Pwm ◽  
Space Vector ◽  
Line Voltage ◽  
Third Harmonic ◽  
Frequency Converters ◽  
Voltage Frequency

Purpose. The aim of this work is to find a method of controlling high-voltage frequency converters that would provide the smallest voltage drop on the motor, the least loads and oscillation of electromagnetic torque in an accident modes, and evaluate the effectiveness of pulse width modulation (PWM) methods with the injection of third harmonic and space-vector PWM in emergency modes. Methodology. We have applied the mathematical simulation of the electric drive “High voltage frequency converter with cascaded H-bridges – High power asynchronous machine” in Matlab/SimPowerSystem software for comparison of four PWM types – Sinusoidal PWM (SPWM), Balanced sinusoidal PWM (BSPWM), Balanced PWM with injected third harmonic (THPWM) and Space Vector PWM (SVPWM). Results. The method of balancing the line voltage minimizes shock loads during the transition from normal to emergency mode due to such a shift of the zero point and rotation of the phase vectors, in which the amplitude of the line voltage decreases to the minimum possible value, the spatial position of linear vectors remains unchanged. The conditions of optimal injection of the 3rd harmonic are found, which increases the efficiency of power supply use by 7… 30 % in comparison with symmetric sinusoidal PWM. But in some accidents (6-4-4, 4-3-2, 3-2-2) the 3rd harmonic is not effective. The method of balancing the space vectors provides the same conditions and increases the utilization of power supplies by 15.6 %, regardless of the number of damaged modules, which increases the amplitude of the 1st harmonic in case of accidents by 10 ... 26 % compared with sinusoidal PWM. Comparison of methods of space vector PWM (SVPWM), balancing of phase-to-phase voltage with the injection of the 3rd harmonic (THPWM) with sinusoidal PWM shows that SVPWM is the best method at damage of one or two modules and during normal work of the converter (except for the 3-3-2 configuration), ie in the most common cases. Originality. For the first time, a comparison of all methods of pulse-width modulation in emergency modes and the optimal method for each type of accident for 3-6-stage frequency converters is indicated. Practical value of the work is to provide the necessary mathematical apparatus for calculating signals using BSPWM, THPWM and SVPWM in emergency modes. References 17, table 1, figures 6.

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