scholarly journals MILLIMETER-WAVELENGTH RELATIVISTIC MAGNETRON: PROBLEMS OF MICROWAVE POWER EXTRACTION

2021 ◽  
pp. 80-84
Author(s):  
N.P. Gadetski ◽  
V.G. Korenev ◽  
A.N. Lebedenko ◽  
I.I. Magda ◽  
O.G. Melezhik ◽  
...  
Keyword(s):  
Microwave Power ◽  
Extraction Efficiency ◽  
Axial Direction ◽  
Circular Ring ◽  
Output Waveguide ◽  
Power Extraction ◽  
Millimeter Wavelength ◽  
Millimeter Wavelengths ◽  
Relativistic Magnetron

The relativistic magnetrons operating at millimeter wavelengths demonstrate problems with microwave power extraction, both in the radial and in axial direction. The preferred axial extraction concept can be implemented ei-ther as ‘diffractional output’ or via introduction of additional resonant elements into the output waveguide. In this paper several solutions for axial-directed extraction are discussed, including circular ring ‘antennas’ at the end of the anode-cathode space, and resonance-length rods at the faces of the anode-block cavities. These have allowed increasing the power extraction efficiency by a factor of 101 to 102.

scholarly journals An improved P&O MPPT control algorithm for increasing power extraction efficiency of solar PV module

2019 ◽  
Vol 623 ◽  
pp. 012020
Author(s):  
D Dinesh Kumar ◽  
Challa Babu ◽  
K Jyotheeswara Reddy ◽  
K Kumar ◽  
N K Kumar
Keyword(s):  
Control Algorithm ◽  
Extraction Efficiency ◽  
Solar Pv ◽  
Power Extraction ◽  
Pv Module

Optimization of Microwave-Assisted Extracting of Proanthocyanidins from Purple Cabbage and Evaluation of Antioxidant Activity In Vitro

2012 ◽  
Vol 490-495 ◽  
pp. 3500-3504 ◽  
Author(s):  
Song Lin Li ◽  
Xiao Ming Chen ◽  
Jing Lin
Keyword(s):  
Microwave Power ◽  
Extraction Time ◽  
Power Extraction ◽  
Solid Ratio ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Layer Chromatography ◽  
Optimum Extraction ◽  
Central Composite

A central composite rotatable design combined with response surface methodology was employed to study the effect of microwave assisted extraction (MAE) conditions namely microwave power, extraction time, liquid-solid ratio and ethanol proportion on the proanthocyanidins extraction from purple cabbage. The optimum extraction conditions were as follows: microwave power, 260 W; extraction time, 54s; liquid to solid ratio, 43; and ethanol concentration, 57%. The results showed proanthocyanidins had a significant effect on scavenging of DPPH radicals. At last, proanthocyanidins were identified by thin layer chromatography.

scholarly journals EKSTRAKSI TANIN DARI KULIT KAYU AKASIA DENGAN MENGGUNAKAN MICROWAVE: PENGARUH DAYA MICROWAVE, WAKTU EKSTRAKSI DAN JENIS PELARUT

2017 ◽  
Vol 6 (3) ◽  
pp. 52-57
Author(s):  
Iriany ◽  
Florentina Pandiangan ◽  
Christina Eka P
Keyword(s):  
Atomic Absorption ◽  
Adsorption Capacity ◽  
Microwave Power ◽  
Polar Solvent ◽  
Extraction Time ◽  
Solvent Ratio ◽  
Microwave Assisted Extraction ◽  
Power Extraction ◽  
Microwave Assisted ◽  
Assisted Extraction

Tannin is one of complex polyphenol compound which soluble in polar solvent. Tannin could be extracted from acacia bark. This study aims to examine microwave-assisted extraction of tannins under influence of microwave power, extraction time, and solvent and its application to adsorb Cd and Cu. Tannin was extracted from acacia bark with feed-to-solvent ratio (1:20 g/ml). Power of microwave was adjusted 100 W, 180 W, 300 W, 450 W, and 600 W for 1 minute, 3 minutes and 5 minutes respectively using aquadest and ethanol as the solvent. The extracts were analyzed using UV-Vis spectrophotometer. Furthermore, the extract with the highest yield of tannins are used as the adsorbent. The concentration of Cd and cu were analyzed using Atomic Absorption Spectrophotometer. The result showed the highest yield of tannin 26.606 mg/g at 100 W and 3 minutes extraction time using ethanol as the solvent. The result showed that the adsorption capacity of adsorbent from tannin was 3.81 mg/g and 2.26 mg/g for Cd and Cu respectively.

Use of synthetic jet to a fully-active flapping foil for power extraction enhancement

2020 ◽  
pp. 095440622091522
Author(s):  
Yadong Li ◽  
Guoqing Zhou ◽  
Jie Wu
Keyword(s):  
Vortex Shedding ◽  
Extraction Efficiency ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Foil Surface ◽  
Power Extraction ◽  
Flapping Foil ◽  
Extraction Performance ◽  
Rotational Motions ◽  
Inclined Angle

The power extraction performance of a fully-active flapping foil with synthetic jet is numerically investigated in this work. An elliptic airfoil with ratio of 8, which is placed in a two-dimensional laminar flow, is adopted to extract power from the flow. The foil implements the imposed translational and rotational motions synchronously. A pair of synthetic jets with the same frequency and strength is integrated into the upper and lower surfaces of flapping foil. As a result, the flow field around the foil could be affected by the synthetic jets greatly. At the Reynolds number of 1000 and the pitching axis location of half chord, the effects of the jet strength, the inclined angle between the jet direction and the chord line, as well as the phase angle between the synthetic jets and the flapping motion on the power extraction performance are systematically investigated. Compared with the traditional flapping foil, it is demonstrated that the enhancement of power extraction efficiency can be achieved with the help of synthetic jets. Based on the numerical analysis, it is indicated that the jet flow on the foil surfaces alters the vortex-shedding process and modifies the pressure distribution on the foil surface. As a result, the overall power extraction of the flapping foil can be benefitted.

scholarly journals Synchronization of pulsed and continuous-wave IMPATT oscillators in the millimeter wavelength range. Part 1. Generator designs and a generalized model of their external signal synchronization

2021 ◽  
pp. 10-20
Author(s):  
N. F. Karushkin
Keyword(s):  
Quality Factor ◽  
Output Power ◽  
Wavelength Range ◽  
Microwave Power ◽  
Output Power Level ◽  
Great Promise ◽  
Frequency Noise ◽  
Power Sources ◽  
Impatt Diode ◽  
Millimeter Wavelength

Advances in the development of ultrahigh-frequency semiconductor electronics open wide opportunities for developing optimal schemes and designs of microwave power sources in the millimeter wavelength range providing high stability of the frequency and electromagnetic oscillation phase. Synchronized diode generators used in transmit/receive module for active phased array antennas, coherent low-power radar stations, etc. show great promise. The mode of external synchronization of semiconductor generators allows effectively implementing the task of creating output stages of the transmitters with high gain factor, low frequency noise and an output power level corresponding to the maximum power mode. This article presents the first of two parts of the study, which summarizes the results achieved so far in the development of synchronized oscillators based on impact ionization avalanche transit-time (IMPATT) diodes. The first part presents the electrodynamic designs of the oscillators, which are synchronized with an external source of microwave oscillations and contain a resonant oscillating system with a silicon IMPATT diode. The silicon two-drift IMPATT diode was chosen as an active element due to the fact that its use allows reaching significant levels of pulsed microwave power – an order of magnitude higher than those of the most well-known HEMT and pHEMT transistors in the millimeter wavelength range. It is shown that to reduce losses, the oscillating system should be made in the form of a radial resonator with a diode casing, which has distributed parameters. This eliminates the use of additional reactive inhomogeneities in the initial cross-section of the waveguide section of the generator. Due to the low quality factor of the resonant casing of the diode, the generalized quality factor of the microwave circuit takes the minimum value required to implement a stable generator synchronization process in the millimeter wavelength range. The second part of the work will be devoted to synchronized pulse generators with an output power of 20–150 W.

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