scholarly journals COHERENT PROPAGATION OF LASER BEAMS IN MCF FIBERS

2019 ◽  
Vol 47 (1) ◽  
pp. 21-23
Author(s):  
A.A. Balakin ◽  
S.A. Skobelev ◽  
A.V. Andrianov ◽  
E.A. Anashkina ◽  
A.G. Litvak
Keyword(s):  
Solid State ◽  
Optical Fibers ◽  
High Efficiency ◽  
Radiation Power ◽  
Experimental Studies ◽  
Pump Energy ◽  
Total Power ◽  
Beam Power ◽  
Self Focusing ◽  
Weakly Coupled

The successful development of fiber-optic technologies in recent decades has stimulated research on the replacement of components of solid-state laser systems with fiber components, which can drastically change the attractiveness of the corresponding applied developments. Yielding on the energy characteristics of solid-state systems, fiber lasers and nonlinear optical devices have high efficiency of conversion of pump energy to radiation energy associated with waveguide geometry, high quality of the spatial profile of the laser beam, as well as low cost, compactness, lack of alignment in work process. Note that the maximum achievable radiation power in a single fiber is limited primarily by the process of self-focusing, which leads to fiber damage. The use of a multi-core fiber (MCF), consisting of identical equidistant weakly coupled optical fibers, makes it possible to realize initially coherent propagation of laser radiation with a total power noticeably higher than it can be transmitted in a single optical fiber. However, as theoretical and experimental studies have shown, such systems have its own critical power (Balakin et al., 2016) whereby the self-focusing of the quasihomogeneous distribution of the wave field and its separation into a set of incoherent structures occurs. Therefore, we have considered a small-sized optical system of 2N identical weakly coupled optical fibers arranged in a ring (Balakin et. al., 2018). In such systems, it is possible to find stable distributions of intense wave beams, which allow coherent radiation transport over long distances. The total radiation power in the found distributions can significantly (up to 2N times) exceed the critical self-focusing power in continuous media. This manifests itself most clearly for the distribution of un ~ (-1)n with antiphase fields in neighboring waveguides, which is stable at an arbitrary wave beam power. Direct numerical simulation of a nonlinear wave equation confirms the stability of the field distributions found. The research was supported by the RAS Presidium Program «Nonlinear dynamics: fundamental problems and applications».

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

High-Efficiency Longitudinal Diode Bar Pumping of Solid-State Lasers.

1994 ◽  
Author(s):  
Todd S. Rose ◽  
James S. Swenson ◽  
Renny A. Fields
Keyword(s):  
Solid State ◽  
High Efficiency ◽  
Solid State Lasers

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Design of a High-Efficiency 40-kV, 150-A, 3-kHz Solid-State Pulsed Power Modulator

2012 ◽  
Vol 40 (10) ◽  
pp. 2569-2577 ◽  
Author(s):  
Seung-Bok Ok ◽  
Hong-Je Ryoo ◽  
Sung-Roc Jang ◽  
Suk-Ho Ahn ◽  
Gennadi Goussev
Keyword(s):  
Solid State ◽  
High Efficiency ◽  
Pulsed Power

scholarly journals Carbon nanotube film replacing silver in high-efficiency solid-state dye solar cells employing polymer hole conductor

2015 ◽  
Vol 19 (10) ◽  
pp. 3139-3144 ◽  
Author(s):  
Kerttu Aitola ◽  
Jinbao Zhang ◽  
Nick Vlachopoulos ◽  
Janne Halme ◽  
Antti Kaskela ◽  
...  
Keyword(s):  
Solar Cells ◽  
Carbon Nanotube ◽  
Solid State ◽  
High Efficiency ◽  
Carbon Nanotube Film ◽  
Dye Solar Cells

52.2: Hybrid Tandem White OLEDs with High Efficiency and Long Life-time for AMOLED Displays and Solid-State Lighting

2010 ◽  
Vol 41 (1) ◽  
pp. 778 ◽  
Author(s):  
Tukaram K. Hatwar ◽  
Jeffrey P. Spindler ◽  
Marina Kondakova ◽  
David Giesen ◽  
Joseph Deaton ◽  
...  
Keyword(s):  
Solid State ◽  
High Efficiency ◽  
Life Time ◽  
Solid State Lighting ◽  
Long Life ◽  
White Oleds

Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate

2005 ◽  
Vol 2005 (11) ◽  
pp. 733-735 ◽  
Author(s):  
Nemai C. Ganguly ◽  
Sanjoy Dutta ◽  
Mrityunjoy Datta ◽  
Prithwiraj De
Keyword(s):  
Solid State ◽  
Ammonium Nitrate ◽  
High Efficiency ◽  
Solvent Free ◽  
High Melting ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Regioselective Nitration ◽  
Cerium Iv Ammonium Nitrate

Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.

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