high peak power microwave pulses

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Coherent summation of emission from relativistic Cherenkov sources as a way of production of extremely high-intensity microwave pulses

Coherent summation of emission from relativistic Cherenkov sources as a way of production of extremely high-intensity microwave pulses

The use of an ultra-short seed EM pulse to control the phase of the SR source means that several such radiators could be phase-synchronized from a single HPM source. As the peak power of a seed signal is only tens of kilowatts then many identical signals could be formed by splitting a single pulse from a master SR generator. This generator could be very similar to these under control. Thus, multi-channel, phase- adjustable arrays of SR generators could be created and utilize effectively the power of multi-gigawatt and even subterawatt- range voltage modulators which usually form accelerating pulses with the rise time exceeding 1 ns. Another advantage of an external signal’s phase control is the decreased stability requirements of the voltage and current fronts.
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High Power Microwave Sources and Applications

High Power Microwave Sources and Applications

Abstract — There has been considerable interest recently in high power microwave (HPM) sources for nonlethal directed energy weaponry applications. Many of these sources that are being developed are derivatives of sources that are well known to the vacuum electronics community. Others are unique to the HPM community and have no analog in traditional microwave sources. For electronic attack (referred to in the media as the “e- bomb”), HPM sources are being developed that provide peak powers that exceed 1 GW at frequencies on the order of 1 GHz in short pulses, typically on the order of 100 ns. The technology that is used to drive such sources has its roots in pulsed power, and a comprehensive understanding of their behavior requires the use of tools that have been developed in the plasma physics community. The ever- increasing reliance on the use of microprocessors that have increasing density of circuits packaged on a chip makes such systems increasingly vulnerable to HPM. This paper will provide an overview of HPM sources, their applications, and will highlight areas of intense, ongoing research activity.
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Low-Power Microwave Induced Thermoacoustic Imaging: Experimental Study and Hybrid FEM Modeling

Low-Power Microwave Induced Thermoacoustic Imaging: Experimental Study and Hybrid FEM Modeling

Abstract—Microwave induced thermoacoustic imaging (TAI) is a hybrid imaging technique combining microwaves and ultrasound waves to achieve both superior spatial resolution and high image contrast. Here, we present results from a hybrid finite element model and an experimental setup using a microwave peak power of less than 5 kW (average power of only 4.5 W), significantly less than for comparable imaging performance in previous works. Microwave pulses with a duration less than 1 µ s are used to excite ultrasound waves with a frequency higher than 1 MHz. Experimental measurements show agreement with simulation results using hybrid finite element modeling capturing microwave heating and acoustic wave propagation. Simulations suggest targets with a conductivity of approximately 0.9 S/m yield the strongest thermoacoustic signatures. Both B-mode images and time-reversal based reconstructed images are obtained and clearly demonstrate the enhanced contrast and high resolution by exploiting the dielectric absorption properties of microwaves and the sub-millimeter resolution of ultrasound. The use of a time reversal algorithm on recorded data demonstrates the effectiveness of TAI for biomedical applications. Standing wave patterns are identified in targets and their relation to the target characteristics and their effect on the resulted images are investigated. The novelty of this work is in lowering the microwave average power while still being able to detect induced acoustic signals, along with developing a numerical model to provide an insight into the imaging process and analyze anomalies in image reconstruction.
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Characteristics Analysis of Repetition Frequency High-Power Microwave Pulses in Atmosphere

Characteristics Analysis of Repetition Frequency High-Power Microwave Pulses in Atmosphere

In this work, a semi-analytical model for the propagation of the repetition frequency HPM pulses is presented. Starting with the continuity equation, which describes the electron density evolution due to the repetition frequency HPM pulses, we analyze the effects of different parameters of the repetition frequency HPM pulses on the air breakdown threshold, such as single pulse field intensity, pulse width and repetition frequency etc. In particular, a critical repetition frequency under which the pulses reaches the electron density is equal to that of the air breakdown is investigated. The air breakdown criterion for the propagation of the repetition frequency HPM pulses propagates in the atmosphere has been derived. The numerical results provide insights for the air breakdown process due to the repetition frequency HPM pulses.
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C. Key words Microwave route, nickel ferrite, ac conductivity, dielectric constant, dielectric loss.

C. Key words Microwave route, nickel ferrite, ac conductivity, dielectric constant, dielectric loss.

Details of the preparation of nickel ferrite had been reported in our previous work [5].In brief, the nickel oxalate, iron oxalate and urea were mixed in weight ratio 1:1:5 and ground well in a pestle and mortar. Resultant solid was placed in a crucible and ignited in microwave oven. The reaction was found to be completed in about ten minutes at high power level and brown crystalline nickel ferrite material is formed. The synthesis scheme is shown in fig (1)..Analysis of X-ray diffraction reveled that, the prepared nickel ferrite is monophasic with cubic spinel structure.SEM images show that, the particles of NiFe 2 O 4 form self assembled
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RF Peak Power Analyzer

RF Peak Power Analyzer

Two adjustable markers can read the power at any point across the waveform. In addition, the markers can be used to define the portion of the waveform in which the maximum power, minimum power, long term average power and peak to average ratios are measured. This is especially useful for characterizing the power level over a portion of the top of a pulse. An auto measure function measures and calculates 15 common power and timing parameters. All parameters for up to four active channels are summarized in a Text display and are also available as user defined display parameters above the Graph display.
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Low complexity algorithm for PAPR reduction in OFDM system adopting SUI channel model

Low complexity algorithm for PAPR reduction in OFDM system adopting SUI channel model

activities in OFDM have grown tremendously during last two decades. Due to its advantageous features like high spectral efficiency, easy equalization and robustness to frequency selective fading channel, the OFDM has been adopted by many broadband wireless communication standards like DAB, DVB-T, IEEE 802.11, 802.16 and UWB communication systems. Besides so many advantageous and favourable features, there exist some major drawbacks of OFDM which must be resolved for getting all the advantages. Therefore, for overall improvement in the performance of OFDM system, it is required to handle all these issues separately. This thesis presents brief review of major problems of OFDM system with their existing solutions. The main focus of work was to provide an appropriate solution to each and every major problem like high PAPR, timing synchronization, frequency synchronization and ICI reduction. After the review of different concerns and their solutions, following conclusions drawn:
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A Preliminary Investigation into the Mediating Role of Positive Affect in the Development of Posttraumatic Stress Disorder among African American Female Sexual Assault Survivors

A Preliminary Investigation into the Mediating Role of Positive Affect in the Development of Posttraumatic Stress Disorder among African American Female Sexual Assault Survivors

The MRIMOs effect has been studied for several years. In the past, people have studied various aspects of MRIMOs, such as its temperature dependence [4], microwave power dependence [30], microwave frequency dependence [4] and microwave polarization dependence [32, 34]. All these studies enriched details of the physical contributions to the MRIMOs, and on the other hand, provided physical background toward its application. Since the MRIMOs are dealing with microwave or terahertz [36] radiation, their applications in microwave or terahertz detection are expected. Through the above discussed studies,and others [11–18, 20–38], the microwave effect on 2DES has been well studied and most of the physical properties were measured directly on the sample. Interestingly, there were preliminary experimental studies of the indirect measurements of MRIMOs carried out by Mani et al. [15, 16]. They exhibited the microwave reflection from 2DES and microwave transmission through 2DES. Both the reflection and the transmission are active in the regime of MRIMOs. More than that, there are different theories about MRIMOs that predict the existence of microwave absorption from 2DES. In the displacement model [49], Lei et al. found a correlation between microwave absorption and MRIMOs. They claimed that there is maximum microwave absorption at cyclotron resonance or its higher orders. Radiation driven electron orbit model [57] suggests that there is a huge and broadened absorption peak at the cyclotron resonance. Hereby, we carried out a systematic study of the microwave reflection from 2DES, trying to correlate the observed reflection signals with MRIMOs.
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Analysis of Reflection Properties of High Power Microwave Propagation in Mixture Atmosphere

Analysis of Reflection Properties of High Power Microwave Propagation in Mixture Atmosphere

When high power microwave (HPM) pulse propagates in atmosphere, the breakdown will occur if the correspond- ing region where the breakdown threshold is lower than the HPM electric field intensity. The free electrons which exist in the atmosphere are accelerated, the impact ioniza- tion is expected to occur when those accelerated electrons interacts with the neutral molecules, this process gener- ates new electrons, the new electrons will be accelerated and the impact ionization will occur again, engendering more electrons. Due to the chain ionization, the electron density in the atmosphere rise sharply in a short time and space-time dependent plasma is formed [1]. The plasma will have some negative impacts on the HPM, bringing some nonlinear effects, such as reflection, absorption at- tenuation and etc. Because of the pulse width is limited, and it will take some time for the electrons produced by ionization reach the density which can significantly ab- sorb the pulse, but before that time, the leading edge of the pulse has passed, and therefore, the attenuation occurs only in the tail. This mechanism is called as “tail erosion” [1]. Some theoretical and experimental work has been reported in the past few years. Woo and DeGroot [2] ob- tained the kinetic and hydrodynamic description of this problem by reduced the Boltzmann equation. Ali [3] has investigated the breakdown parameters for very high val- ues of E/p. Kuo and Zhang [4] conducted a chamber ex-
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Solar Peak Power Tracker

Solar Peak Power Tracker

In applications where photovoltaic arrays are used to provide energy, maximum power trackers are used to correct for the variations in the current-voltage characteristics of the solar cells. As shown in the typical silicon cell I-V curve, as the output potential of the string rises, the string will produce significantly less current. The current-voltage curve will move and deform depending upon temperature, illumination, and consistency of cell quality in the string. For the array to be able to put out the maximum possible amount of power, either the operating voltage or current needs to be carefully controlled.
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ABSTRACT : The use of OFDM causes a high peak to- average (power) ratio (PAR

ABSTRACT : The use of OFDM causes a high peak to- average (power) ratio (PAR

While the theoretical aspects of large-scale MU-MIMO systems have gained significant attention in the research community, much less is known about practical transmission schemes. As pointed out in practical realizations of large- scale MIMO systems will require the use of low cost and low-power radio-frequency (RF) components. To this end, reference proposed a novel MU pre coding scheme for frequency-flat channels, which relies on per-antenna constant envelope (CE) transmission to enable efficient implementation using non-linear RF components. Moreover, the CE pre coder of forces the peak-to-average (power) ratio (PAR) to unity, which is not necessarily optimal as in practice there is always a trade-off between PAR, error-rate performance, and power amplifier efficiency.
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Relationships between force-time curve variables and jump height during countermovement jumps in young elite volleyball players

Relationships between force-time curve variables and jump height during countermovement jumps in young elite volleyball players

are types of vertical jumps, and constitute the most useable tests for the assessment of the neuromuscular coordination of athletes (Claudino et al., 2017). In addition, CMJ is used for the assessment of the fitness level of injured athletes after rehabilitation periods, and for detecting their fitness to return to play (Clan- ton, Matheny, Jarvis, & Jeronimus, 2012; Henderson, Barnes, & Portas, 2010; Olsson et al., 2013). Force- time (F-T) curve variables of CMJ are utilised to assess neuromuscular and biomechanical features related to lower extremity dynamics (Claudino et al., 2017; Kol- lias et al., 2001). Additionally, vertical jump tests are performed in accordance to various aims, such as the assessment of the developed force and power in elite ath- letes who participate regularly in competitions (Cormie, McGuigan, & Newton, 2010). McGinnis et al. (2016) have used CMJ to assess the effect of fatigue on per- formance. Olsson et al. (2013) showed that CMJ and other types of jumps could be used for the assessment and evaluation of athletes’ performances, after Achilles tendon tears. Previous research studies have shown that CMJ has an appropriate validity for assessing explosive
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Microwave-Assisted Extraction of Phytochemicals in Cogongrass (Imperata cylindrica) Rhizome

Microwave-Assisted Extraction of Phytochemicals in Cogongrass (Imperata cylindrica) Rhizome

Microwave irradiation has received a lot of attention. It is a feasible green solvent extraction method as it utilizes water or alcohols at elevated temperature and controlled pressure conditions. Microwave extraction emerges as a promising technique from an economical point of view, being inexpensive, simple and efficient. Cogongrass (Imperata cylindrica) rhizome is a good source of antioxidants such as phenolic, flavonoid and saponin. The rhizome-root part serves as traditional medicine for the treatment of a wide range of infections. In our research, different parameters such as power of microwave (50, 75, 100, 125, 150 W), frequency of microwave (15, 20, 25, 30, 35 GHz), duration of the microwave irradiation (1.5, 2.0, 2.5, 3.0, 2.5 min), ratio of liquid to solid (water: material, 1.0:1.0, 1.5:1.0, 2.0:1.0, 2.5:1.0, 3.0:1.0), extraction temperature (70, 75, 80, 85, 90 o C), number of extraction cycles (1, 2, 3, 4, 5) affecting to the
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PERFORMANCE ANALYSIS OF PAPR REDUCTION IN OFDM USING SLM & PTS TECHNIQUE

PERFORMANCE ANALYSIS OF PAPR REDUCTION IN OFDM USING SLM & PTS TECHNIQUE

These techniques are described in papers [24] [25] [23] these techniques could reduce the high PAPR problem of OFDM system or in other words compensates the non linear effects of HPA (High Power Amplifier). Through automatic adjusting of the input constellation with the help of least hardware; the non linear HPA deviation could be handled. The convergence time of pre-distorter and the MSE (Mean Square Error) can be decreased through broadcasting techniques with the help of suitable training signal design.

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Journal of Applied Pharmaceutical Science

Journal of Applied Pharmaceutical Science

The major conclusion arising out of this research was that the antioxidant capacities of some of the pulses could be improved by thermal processing methods that resemble cooking. Enhanced activity of the pulses shown after thermal processing in water might be due to enhanced extraction of polar polyphenols like gallo-ellagitannins, and less polar polyphenols like phenolic acids or flavonoid glycosides, which have less solubility in normal water but enhanced solubility in hot water. Since a strong correlation was not observed between the antioxidant profiles of the pulses, it would be better to adjudicate the antioxidant activities of the pulses as judicious consortium of different groups of bioactives that were present in the aqueous extracts. It was proposed that there were some improvements in the antioxidative potential of the pulses on heat treatment with water, which implies their role as functional foods, even after cooking.
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An Evaluation of Factors Affecting Pulses Production and Consumption in Bihar

An Evaluation of Factors Affecting Pulses Production and Consumption in Bihar

Pulses are nature’s precious gift to mankind because this crop is supplement nutritious food to our vegetarian population as protein, feed for our cattle and also helping in improving soil health and productivity of other crops (Singh et al., 2013). The growth and development of human being is met with pulses still today and it from a vital part in the diet of poor as well as the rich. Pulses are grown all over the world and account for almost 70 million hectares in area and above 45 million tonnes of production (Choudhary, 2013). Among the pulses producing countries, India ranks second and contributes about 20 percent to world production with 33 percent of pulses area; however it ranks a poor 98 th in pulses productivity (Reddy 2009). Pulses share in total food grain production has registered continuous decline from 17 percent in 1961 to below 7 percent in 2011. Data for 2014-15 shows that total production of pulses was 17.1 million tons in the country however the total demand during the same year was 23.6 million ton. In the year 2014-15 the country had to import around 4.6 million ton of pulses (Chand et al., 2015). As per the recommendation of ICMR 65 gram/day/capita pulses are required but the availability was only 30 gram/day/capita during 2013-14. The reduction in per capita availability of pulses has been recorded since 1951 when availability was around 70 gm/day/capita (Singh et al. 1993). The main reasons for continuous declining in per capita availability of pulses was mainly due to stagnation in pulses production around 17 to 18 million tonnes during the last five decades. In the period rapid increase in population of the country and black marketing and hoarding of pulses by traders also.
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Medical Cutting Tools

Medical Cutting Tools

Since 1966 constant innovation, performance based approach and market recognized and consolidated superior accuracy, achieved in a wide variety of manufacturing applications, have led C.B.Ferrari to a world leading position in high precision 5-Axes CNC machining centers solutions.

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GaN or GaAs, TWT or Klystron - Testing High Power Amplifiers for RADAR Signals using Peak Power Meters

GaN or GaAs, TWT or Klystron - Testing High Power Amplifiers for RADAR Signals using Peak Power Meters

Figure 8 shows three waveforms measured using the test set- up in Figure 7 using the 55 Series Peak Power Sensors. The input waveform is displayed on CH1, reflected waveform on CH3 and the output on CH2. Note that automated measurements performed on all three channels are displayed to the left of the trace display window. The measurements can be transferred to a spreadsheet to perform the necessary gain and return loss calculations, as well as other parameters of interest. In an automated test environ- ment the same measurements can be accessed through remote programming to perform gain and return loss computations as well. Droop measurement capabilities are shown in Figure 9 using the Boonton 55318 USB Peak Power Sensor. Power droop can be measured either using the automated pulse measurements or us- ing automated marker measurements as well as horizontal mark- ers. The automated marker measurements can display the droop placing markers at the desired points on the waveform and using MkRatio. Alternatively reference lines can be placed on the vertical axis at the desired high and low points of the pulse to measure the droop. Automated Pulse measurements are computed automati- cally based on pulse definition irrespective of marker or reference line placements.
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Microwave pyrolysis of automotive paint 
		sludge (APS) at medium microwave power: Effect of microwave absorber 
		loading

Microwave pyrolysis of automotive paint sludge (APS) at medium microwave power: Effect of microwave absorber loading

Mass automotive production nowadays leads to higher amount of waste produced. Based on the statistical report, the production of vehicles is increasing from year to year [1]. By having this higher production of vehicles leads to higher production of waste regardless it is hazardous waste or not. One of the wastes produced by the automotive industry is automotive paint sludge (APS). This automotive paint sludge has been gazetted as hazardous or schedule waste (SW 416) by Malaysian Government [2]. Thus, it must be sent to authorize disposal party such as Kualiti Alam for Malaysia and the handling cost is high since it is categorized as hazardous waste. Even though it is categorized as hazardous waste, this APS contains very valuable constituents that can be recovered [3]. There were many attempts that have been made in order to recover or gain some value and lower the overall processing costs of APS by creating useful products from APS [4-7].
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Efficient, High Aspect Ratio Microhole Drilling with Rapidly Repeated Pulses

Efficient, High Aspect Ratio Microhole Drilling with Rapidly Repeated Pulses

The necessity for micro holes spans across a wide range of industrial applications with nearly endless boundaries. From electronics and X-Ray apertures to micro fluidics and heat transfer phenomenon, the advancement of precision ablation will undoubtedly be of benefit. A novel use of micro holes is the creation of flexible circuits in which lasers ablate organic material from gold contact pads. The precision required is attributed to the need to remove material without damaging surrounding areas. Applications of such technology can be seen wherever electronics are present. Most notably, flexible circuits hope to advance the sciences of printers, automotive industries, as well as medical electronics. Medical devices lend themselves perfectly to the idea of micro-hole drilling; Catheters, irrigation needles, and precise orifices for oxygen regulators are some of the direct applications. Trends towards fabricating pinholes, air slits, collimators, and spatial filters for non-destructive, non-contact illumination devices are requiring high dimensional tolerance, repeatability, and resolution. Along with the medical device industry, pharmaceuticals and beverage packaging companies stand to benefit from precision holes. Improved leak test equipment is pushing the limits of calibrated leak holes. Smaller, more precise flow orifices are of high demand for accuracy and repeatability of flow calculations. Such innovations will immediately be used in foil packages in the medical device industry as well as blister packs and plastic ampoules for pharmaceutical reasons. Other applications currently employed are aerospace combustor liners, fuel injectors, filters, turbine blades, and air bearings.
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