scholarly journals A Systematic Review of HPM Energy Absorbers for Building Applications

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6061
Author(s):  
Krzysztof Majcher ◽  
Michał Musiał ◽  
Wojciech Pakos ◽  
Adrian Różański ◽  
Maciej Sobótka ◽  
...  
Keyword(s):  
Construction Materials ◽  
High Power Microwave ◽  
Building Products ◽  
Civilian Protection ◽  
The Subject ◽  
Paint Coatings ◽  
Energy Absorbers ◽  
Masonry Units ◽  
Power Microwave

A modern weapon, high power microwave (HPM) pulses, can have a profound effect on the quality of functioning of society as the use of this weapon can result in damage to or destruction of electronic equipment and computer and telecommunications systems, both military and civilian. Protection against the energy of HPM pulses can be achieved in two basic ways: by using radiation-absorbent materials (RAM) or artificial electromagnetic (EM) structures. If the object to be protected is a building, protection based on RAM is used. Hence, this literature review focuses on the possibilities of using HPM energy absorbers in building products and structures. Attention is concentrated on four basic types of elements: claddings, concrete and mortar, small-sized elements (bricks, hollow masonry units), and paint coatings. In each of the categories, examples of HPM radiation absorbers having a high potential to be combined with basic construction materials are given on the basis of the literature on the subject.

MULTISTAGE MICROSTRIP UHF LOAD

2018 ◽  
pp. 53-57 ◽  
Author(s):  
G. G. Savenkov ◽  
V. P. Razinkin ◽  
A. D. Mekhtiev
Keyword(s):  
Frequency Response ◽  
Frequency Band ◽  
High Power ◽  
Two Stage ◽  
High Power Microwave ◽  
Modelling Method ◽  
Optimal Values ◽  
Inductive Elements ◽  
Power Microwave

Applications of modern terminal loads and its relevant disadvantages are described in this paper. The decomposing method of wideband microwave high power microstrip loads design is proposed in this paper with purpose of matching quality improving. Multiple extension of multistage load bandwidth is provided by using of external matching circuit and internal matching inductive elements. The maximum reachable bandwidth of multistage load is estimated and optimal values of mathing circuit elements are founded on basis of equivalent lumped scheme. The topology of microstrip two-stage high power microwave load is developed and its frequency response, calculated via numeric electrodynamic modelling method is outlined in the paper. Modelling results show good matching quality of considered load at the frequency band below 3,5 GHz.

scholarly journals Microwave assisted convective drying of kale (Brassica oleracea L. var. sabellica L.) at stationary and non-stationary conditions

2018 ◽  
Author(s):  
Dominik Mierzwa ◽  
Justyna Szadzińska
Keyword(s):  
Ascorbic Acid ◽  
Convective Drying ◽  
Drying Time ◽  
High Power Microwave ◽  
Microwave Application ◽  
Colour Measurements ◽  
Stationary Conditions ◽  
Quality Of Products ◽  
Power Microwave

This paper concerns hybrid drying of kale. Eight different schedules of drying were tested experimentally to find out the influence of microwave enhancement on the kinetics (drying rate and time), energy consumption of convective drying and quality of products. Different power of microwaves and modes of microwave application were tested. Quality of products was assesed through water activity and colour measurements, as well as retention of ascorbic acid. The results obtained in the studies allowed to state that intermittent application of high-power microwave pulses may lead to a meaningful reduction of drying time and high quality of the dry products.Keywords: hybrid drying; intermittent drying; kale; ascorbic acid; colour  

scholarly journals Methods of Protecting Buildings against HPM Radiation—A Review of Materials Absorbing the Energy of Electromagnetic Waves

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5509
Author(s):  
Krzysztof Majcher ◽  
Michał Musiał ◽  
Wojciech Pakos ◽  
Adrian Różański ◽  
Maciej Sobótka ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Nickel Powder ◽  
Construction Materials ◽  
Wave Radiation ◽  
Special Role ◽  
Protective Measures ◽  
Building Envelopes ◽  
High Power Microwave ◽  
The Military ◽  
Power Microwave

The pulsed high power microwave (HPM) technology has been developed worldwide for over 20 years. The sources of HPM pulses are a weapon of mass destruction. They pose danger especially to computer and telecommunications equipment and systems, both the military and civilian ones. This paper presents a survey of literature on electromagnetic wave radiation absorbing and shielding materials to be used in construction. Relevant protective measures should include the shielding of buildings or their parts and the absorption of radiation by building envelopes and their elements. The main focus is on the possibilities of improving the shielding and absorptive properties of common construction materials, such as concrete, mortars and synthetic resins. The survey covers the following groups of materials: carbon-based admixtures, nickel powder, iron powders, ferrites, magnetite and polymers. The final part of the survey is devoted to hybrid foam microwave absorbers in which the shape of the material’s inner structure and that of its surface play a special role.

scholarly journals A Tesla-type long-pulse generator with wide flat-top width based on a double-width pulse-forming line

2018 ◽  
Vol 36 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Sheng Liu ◽  
Jian-Cang Su ◽  
Xibo Zhang ◽  
Ya-Feng Pan ◽  
Hong-Yan Fan ◽  
...  
Keyword(s):  
Pulse Generator ◽  
Electron Beams ◽  
Output Pulse ◽  
High Power Microwave ◽  
Pulse Generators ◽  
Microwave System ◽  
Current Electron ◽  
Long Pulse ◽  
Power Microwave

AbstractTo produce pulses with good flat-top quality, pulse-forming lines (PFLs) have been widely used in the field of Tesla-type pulse generators. To shorten the physical length of the PFL, a double-width PFL (DWPFL) is proposed that doubles the output pulse width while maintaining flat-top quality. A repetitively 10 GW Tesla-type long-pulse generator producing pulses with flat-top width of about 110 ns was developed with a coaxial DWPFL to produce high-current electron beams. Electron beams of about 10 GW with flat-top widths of about 110 ns were obtained on a planar vacuum diode load. With this pulse generator and a C-band high-power microwave system, microwaves of ~2.2 GW power and full-width at half-maximum of 101 ns were generated. The experiment demonstrates the feasibility and ideal output waveform quality of the DWPFL.

Low-Frequency Noise in SiO2/AlGaN/GaN Heterostructures on SiC and Sapphire Substrates

1999 ◽  
Vol 595 ◽  
Author(s):  
N. Pala ◽  
R. Gaska ◽  
M. Shur ◽  
J. W Yang ◽  
M. Asif Khan
Keyword(s):  
High Power ◽  
Field Effect Transistors ◽  
Low Frequency ◽  
Oxide Semiconductor ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
High Power Microwave ◽  
Heterostructure Field Effect Transistors ◽  
Power Microwave

AbstractThe low-frequency noise in GaN-based Metal-Oxide-Semiconductor Heterostructure Field Effect Transistors (MOS-HFETs) and HFETs on sapphire and n-SiC substrates were studied. Hooge parameter at zero gate bias was calculated about 8 × 10−4 for both types of the devices. The AlGaN/GaN MOS-HFETs exhibited extremely low gate leakage current and much lower noise at both positive and negative gate biases. These features demonstrate the high quality of the SiO2/AlGaN heterointerface and feasibility of this technology for high-power microwave transmitter and high-power, high-temperature switches.

scholarly journals Improving the Properties of Clay Soil by Using Laterite Soil for Production of Bricks

2019 ◽  
Vol 15 (2) ◽  
pp. 134-141
Author(s):  
Anteneh Geremew ◽  
Yibas Mamuye
Keyword(s):  
Laboratory Tests ◽  
Construction Materials ◽  
High Water ◽  
Lateritic Soil ◽  
Laterite Soil ◽  
Optimum Firing ◽  
Masonry Units ◽  
Temperature Furnace ◽  
Optimum Firing Temperature

AbstractNowadays, the utilization of locally accessible materials is a crucial stage for sustainable, economical building material on the earth’s surface. Within them, brick is one of the commonly used construction materials around Jimma town due to the availability of clayed soil. Nevertheless, brick produced by small micros unskilled enterprises rather than by traditional methods, its quantity was small, and its quality was unsatisfactory because it can easily break, and it has high water-absorbing conduct. The purpose of the investigation was to improve the properties of clayed soil properties by using laterite soil for the manufacturing of bricks for masonry units. In order to achieve this, research used non-probability sampling techniques to collect samples in Jimma area. Then, the collected samples prepared for different laboratory tests and by partially replacing literate soil by 5 %, 10 %, 15 % and 20 % on a clayed soil in order to get optimum property by different mix ratio for different laboratory tests results indicated showed that the lightweight bricks could be made from the approach of this study without any deterioration in the quality of bricks.Additionally, the compressive strength of the blocks optimum at 15 % lateritic soil replaces in clayed soil contents. The optimum firing temperature furnace at a duration burning of brick was at 1000 °C for 5hrs. It has shown that bricks prepared of clay-laterite earth capable of high resisting capacity rather than for beauty.

scholarly journals Low-Frequency Noise in SiO2 /AlGaN/GaN Heterostructures on SiC and Sapphire Substrates

2000 ◽  
Vol 5 (S1) ◽  
pp. 612-618
Author(s):  
N. Pala ◽  
R. Gaska ◽  
M. Shur ◽  
J. W Yang ◽  
M. Asif Khan
Keyword(s):  
High Power ◽  
Field Effect Transistors ◽  
Low Frequency ◽  
Oxide Semiconductor ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
High Power Microwave ◽  
Heterostructure Field Effect Transistors ◽  
Power Microwave

The low-frequency noise in GaN-based Metal-Oxide-Semiconductor Heterostructure Field Effect Transistors (MOS-HFETs) and HFETs on sapphire and n-SiC substrates were studied. Hooge parameter at zero gate bias was calculated about 8 × 10−4 for both types of the devices. The AlGaN/GaN MOS-HFETs exhibited extremely low gate leakage current and much lower noise at both positive and negative gate biases. These features demonstrate the high quality of the SiO2/AlGaN heterointerface and feasibility of this technology for high-power microwave transmitter and high-power, high-temperature switches.

Measuring Service Quality in The Context of Higher Education in Vietnam

2013 ◽  
pp. 77-90
Author(s):  
Yen Nguyen Thi Hoang
Keyword(s):  
Higher Education ◽  
Service Quality ◽  
Exploratory Study ◽  
Measurement Scale ◽  
Education Service ◽  
The Subject

This paper focuses on the understanding of service quality in the context of Vietnamese universities. It proposes an approach for measuring the quality of the higher education service provided by universities in Vietnam. Firstly, an exploratory study was conducted. Then, the set of items which were generated became the subject of a questionnaire that was then administered to 675 students of a Vietnamese university to determine the dimensions of higher education service quality in this context. The obtained results permit us to appropriate a measurement scale which is slightly different from the SERVQUAL scale widely known as the standard for measuring service quality. The results also show that tangible elements, responsiveness and assurance seem to be three specific dimensions of the higher education service of Vietnamese universities.

Thomas More’s Correspondence in a Spanish Ambiance

Moreana ◽  
2002 ◽  
Vol 39 (Number 149) (1) ◽  
pp. 41-60 ◽  
Author(s):  
Eugenio M. Olivares Merino
Keyword(s):  
The Subject ◽  
Selection Of

The recent reprinting of Álvaro de Silva’s 1998 edition of a selection of More’s letters prompts the author to examine the subject of Spanish translations of More, and of de Silva’s general commentary on More’s correspondence and on his relationship to other humanists. The author reflects on aspects of More’s personality as exposed in his letters and uses what he finds as a corrective to several biographical misconceptions. He points out the strengths and weaknesses of de Silva’s work and compares it with that of other translators, particularly Elizabeth Rogers, and notes the particularly Spanish quality of de Silva’s edition.

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