Search results for "high power"
showing 7 items of 17 documents
<title>Family of devices for the study of laser eam behavior in particular conditions</title>
2002
Laser applications in science and technology are based on the special properties of laser radiation, such as monochromaticity, coherence, beam concentration and high power density. Since the laser was discovered, an ever increasing number of applications have been found for it in the most diversified fields. Despite this, its wide possibilities are still by no means fully known or exhausted. Further development is continually taking place in the design of new systems. The generation of the photons is in itself an optic-electronic process. The trajectory of the laser beam is linear. It could be modified by a lens or by a mirror. We built some devices, in order to know how a laser beam could …
Spatial hole burning in thin-disk lasers and twisted-mode operation.
2018
Spatial hole burning prevents single-frequency operation of thin-disk lasers when the thin disk is used as a folding mirror. We present an evaluation of the saturation effects in the disk for disks acting as end-mirrors and as folding-mirrors explaining one of the main obstacles towards single-frequency operation. It is shown that a twisted-mode scheme based on a multi-order quarter-wave plate combined with a polarizer provides an almost complete suppression of spatial hole burning and creates an additional wavelength selectivity that enforces efficient single-frequency operation.
Novel Computational Method for Harmonic Mitigation for Three-phase Five-level Cascaded H-Bridge Inverter
2018
The efficiency of the system is a very important parameter for high power electrical drives applications,. Moreover, in the system the efficiency of the power converter play a fundamental role and for this reason, the soft switching modulation techniques represent the best choice. This paper presents a novel computational method for harmonic mitigation on the output voltage of a five-level, three-phase Cascaded H-Bridge Inverter without solving non-linear equations. Through this simple approach the Working Areas have been identified in which the harmonics reference have minimum amplitude possible. Moreover, polynomial equations to evaluate the control angels have been found. In this way, th…
Selective harmonic mitigation with asymmetrical staircase voltage waveform for a three-phase five-level Cascaded H-Bridge Inverter
2020
Selective harmonics elimination or mitigation strategies are used in all applications where it is necessary to rise the efficiency and reliability of the overall system. This paper presents a simple approach to reduce the low order harmonics amplitude of an asymmetrical staircase voltage waveform for a five-level, three-phase Cascaded H-Bridge Inverter without solving non-linear equations. Through this simple approach, polynomial equations to evaluate the control angels in real-time operations have been found. The effectiveness of the harmonic mitigation method has been tested through the simulation analysis in MatLab/PLECS environment.
Universal soliton pattern formations in passively mode-locked fiber lasers
2011
International audience; We investigate multiple-soliton pattern formations in a figure-of-eight passively mode-locked fiber laser. Operation in the anomalous dispersion regime with a double-clad fiber amplifier allows generation of up to several hundreds of solitons per round trip. We report the observation of remarkable soliton distributions: soliton gas, soliton liquid, soliton polycrystal, and soliton crystal, thus indicating the universality of such complexes.
Virucidal effect of high power ultrasound combined with a chemical sanitizer containing peroxyacetic acid for water reconditioning in the fresh-cut i…
2015
The use of chlorine-based sanitizers is widespread throughout the fresh produce industry in the process water to maintain microbial safety of produce, avoid cross-contamination and recycle water. In this study, alternative disinfection technologies were investigated due to the negative reports showing chlorine instability in the presence of organic matter and the undesirable by-product residues. Tsunami ® (15.2% peroxyacetic acid and 11.2% hydrogen peroxide) and high-power ultrasound (HPU, 0.56 kW/l, 20 kHz), alone or in combination, were evaluated in lettuce process water analyzing their ability to reduce MNV during either produce washing or water recycling. PAA concentrations of 6.4, 12.8…
Target Cooling Options for Neutron Sources at High Power Densities
2014
Abstract Compact neutron sources in many cases beat large ones when it comes to power density; thus, many issues concerning cooling are shared, and each party can learn a lot from the other facilities. Starting from accrued experience with water cooling at moderate power densities in SINQ over the last 15 years, a brief overview will be attempted showing the relevant parameters and specific approaches at several existing and planned neutron (spallation) sources. Extensions from the established ground of cooling with water will be sketched in two directions. An outline of an experiment planned for freshly determining in a representative geometry the hard limit for water cooling, i.e. full bo…