scholarly journals Analysis and Design of 10-Element Yagi-Uda Antenna

2020 ◽  
Vol 25 (1) ◽  
pp. 1-8
Author(s):  
Mohanad Abdulhamid

AbstractThe main aim of this paper is to come up with a 10-element Ultra High Frequency (UHF) aerial with optimal spacing that gives clear TV reception. A Yagi antenna is chosen for this study due to its high directionality, broadband capability, high gain and the availability of materials locally. An attempt is made to simulate the entire antenna and test it on a Samsung TV set.

2014 ◽  
Author(s):  
Nicholas A. Bishop ◽  
Mohammod Ali ◽  
Jason Miller ◽  
David L. Zeppettella ◽  
William Baron ◽  
...  

Author(s):  
Dmitri Vinnikov ◽  
Tanel Jalakas ◽  
Indrek Roasto

Analysis and Design of 3.3 kV IGBT Based Three-Level DC/DC Converter with High-Frequency Isolation and Current Doubler RectifierThe paper presents the findings of a R&D project connected to the development of auxiliary power supply (APS) for the high-voltage DC-fed rolling stock applications. The aim was to design a new-generation power converter utilizing high-voltage IGBT modules, which can outpace the predecessors in terms of power density, i.e. to provide more power for smaller volumetric space. The topology proposed is 3.3 kV IGBT-based three-level neutral point clamped (NPC) half-bridge with high-frequency isolation transformer and current doubler rectifier that fulfils all the targets imposed by the designers. Despite an increased component count the proposed converter is very simple in design and operation. The paper provides an overview of the design with several recommendations and guidelines. Moreover, the simulation and experimental results are discussed and the performance evaluation of the proposed converter is presented.


2017 ◽  
Author(s):  
Thong Dao ◽  
Frank McGroarty ◽  
Andrew Urquhart

2020 ◽  
Vol 4 (41) ◽  
pp. 35-43
Author(s):  
ALEKSEY A. VASIL’EV ◽  
◽  
ALEKSEY N. VASIL’EV ◽  
DMITRIY BUDNIKOV ◽  
ANTON SHARKO

The use of electrophysical influences for pre-sowing treatment of seeds is an effective way to increase their sowing quality. The use of these methods is limited by the fact that their implementation requires new technological equipment in grain processing lines. This problem is solved more easily when pre-sowing processing is performed using installations for active ventilation and grain drying. (Research purpose) The research purpose is in determining the possibility of using active ventilation units and ultra-high-frequency convective grain dryers for pre-sowing grain processing and to evaluating the effectiveness of such processing using computer modeling. (Materials and methods) It is necessary to ensure the uniformity of processing with external influence the seeds placed in a dense layer. Authors carried out pre-sowing treatment of seeds on real installations. Treated seeds were sown in experimental plots and the results of treatment were evaluated. (Results and discussion) The article presents graphs of changes in grain temperature and humidity during processing. To check the feasibility of pre-sowing treatment, authors performed modeling of air-heat and ultra-high-frequency convective seed treatment processes. Based on the results of field experiments, air-heat treatment stimulates the development of secondary plant roots, contributes to an intensive increase in the green mass of plants; ultra-high-frequency convective seed treatment allows increasing the number of productive stems in plants, the number of ears in one plant. (Conclusions) Technological equipment designed for drying and active ventilation of grain can be effectively used for pre-sowing seed processing. In the course of field experiments, it was revealed the possibility of controlling the structure of the crop using different types of external influence on seeds during their pre-sowing processing.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1943
Author(s):  
Bader N. Alajmi ◽  
Mostafa I. Marei ◽  
Ibrahim Abdelsalam ◽  
Mohamed F. AlHajri

A high-frequency multi-port (HFMP) direct current (DC) to DC converter is presented. The proposed HFMP is utilized to interface a photovoltaic (PV) system. The presented HFMP is compact and can perform maximum power point tracking. It consists of a high-frequency transformer with many identical input windings and one output winding. Each input winding is connected to a PV module through an H-bridge inverter, and the maximum PV power is tracked using the perturb and observe (P&O) technique. The output winding is connected to a DC bus through a rectifier. The detailed analysis and operation of the proposed HFMP DC-DC converter are presented. Extensive numerical simulations are conducted, using power system computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) software, to evaluate the operation and dynamic behavior of the proposed PV interfacing scheme. In addition, an experimental setup is built to verify the performance of the HFMP DC-DC converter.


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