propagation axis
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Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8483
Author(s):  
Tomasz Węsierski ◽  
Robert Piec ◽  
Małgorzata Majder-Łopatka ◽  
Bernard Król ◽  
Wiktor Gawroński ◽  
...  

The publication presents the results of a field test of 2–4 min releases of 96% LNG from a road tanker designed to carry the gas. The release was performed at a pressure of 5.9–6.1 atm at a discharge rate of 1.67–1.78 kg/s from a height of 0.75 m under class B conditions of atmospheric stability. Comparison of the obtained experimental results of the maximum concentrations and the simulation carried out with the EFFECS (11.2.0) software showed that the Gaussian gas model better describes the gas cloud propagation at most control points at this release intensity than the dense gas model. The dense gas model gave only slightly better results along the cloud propagation axis at close distances, not exceeding 25/30 m at ground level. It is shown that concentrations between 71% and 110% LEL are observed at the cloud visibility limit. The maximum value of the temperature drop, in the release axis, at a distance of 4 m amounts to ∆Tmax = 93.3 °C. This indicates that the cloud of the released LNG is almost entirely in the vapour state already in the short distance from the point of release, due to the turbulent outflow of the pressurised gas.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Arturo Sopena ◽  
Alicia Palacios ◽  
Fabrice Catoire ◽  
Henri Bachau ◽  
Fernando Martín

AbstractThe high brilliance of ultrashort X-ray pulses recently generated in free electron lasers will soon open the way to the investigation of non-linear processes that still remain inaccessible due to the smallness of the corresponding cross sections. One of them is stimulated Compton scattering from molecules. In this work, we investigate stimulated Compton scattering from fixed-in-space H2 molecules in the few-hundred eV photon energy range, where both dipole and non-dipole transitions are important. We show that the interference between dipole and non-dipole transitions leads to pronounced asymmetries in the electron angular distributions. These asymmetries strongly depend on molecular orientation, to the point that they can lead to electron emission in either the forward or the backward directions with respect to the propagation axis, or in both directions, or even in the orthogonal direction. This is in contrast with Compton scattering from free electrons or atomic targets.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Victor Pacheco-Peña ◽  
Joseph Arnold Riley ◽  
Cheng-Yang Liu ◽  
Oleg V. Minin ◽  
Igor V. Minin

AbstractPhotonic hooks have demonstrated to be great candidates for multiple applications ranging from sensing up to optical trapping. In this work, we propose a mechanism to produce such bent structured light beams by exploiting the diffraction and scattering generated by a pair of dielectric rectangles immersed in free space. It is shown how the photonic hooks are generated away from the output surface of the dielectrics by correctly engineering each individual dielectric structure to generate minimum diffraction and maximum scattering along the propagation axis. Different scenarios are studied such as dual-dielectric structures having different lateral dimensions and refractive index as well as cases when both dielectrics have the same lateral dimensions. The results are evaluated both numerically and theoretically demonstrating an excellent agreement between them. These results may open new avenues for optical trapping, focusing and sensing devices via compact and simple dual-dielectric structures.


2021 ◽  
Vol 15 (58) ◽  
pp. 365-375
Author(s):  
Mohammed Achoui ◽  
Fethi Sebaa ◽  
Benattou Bouchouicha

The aim of this work is the study of the fatigue behaviour of API X60 steel and the influence of thermal and mechanical treatments. The evaluation of the integrity and safety of welded structures dictates the approach taken in this research. The microstructural observations on the different zones of the weld seam indicates that the variation of heterogeneous structure is a progressive destruction of the strips of lamination which cause a new phase leading to a drop in the mechanical properties requiring treatment after welding. The fatigue cracking rate diverges beyond the threshold of DK, but no deviation of the crack from its propagation axis was noticed, which confirms the correct choice of filler metal over that of the base metal with an overmatching M = 1.1, and the treatments applied to the structure. This fatigue cracking rate transversal to the welding direction initially presents an aspect similar to that of BM but registers a delay as soon as the crack tip enters the second zone (HAZ) then it progresses rapidly. This evolution is characterized by a disturbance due to the repeated change of microstructure.


2021 ◽  
Author(s):  
Yuta Ishii ◽  
Hironori Nakao ◽  
Masaichiro Mizumaki ◽  
Yusuke Wakabayashi ◽  
Taka-hisa Arima ◽  
...  

Abstract A Laguerre–Gaussian (LG) vortex beam having a spiral wavefront can be characterized by its topological charge (TC). The TC gives the number of times that the beam phase passes through the interval [0, 2π] following a closed loop surrounding the propagation axis. Here, the TC of soft X-ray vortex beams is determined using the in-line holography technique, where interference between vortex waves produced from a fork grating and divergent waves from a Fresnel zone plate is observed as a holographic image. The analyses revealed the phase distributions and the TC for the LG vortex waves, which reflects topological number of the fork gratings, as well as for the Hermite–Gaussian (HG) mode waves generated from the other gratings. We also conducted a simulation of the present technique for pair annihilation of topological defects in a magnetic texture. These results may pave the way for development of probes capable of characterizing the topological numbers of magnetic defects.


2021 ◽  
Vol 24 (2) ◽  
pp. 41-48
Author(s):  
Maxim Yu. Ponamarev

In this work, it is shown that the image formed as a result of the passage of coherent radiation through the crystal has certain characteristic features. When the crystal is rotated with respect to the propagation axis of the investigated beam, the formation of the intensity distribution of a complex structure associated with the transformation of the flat image into volumetric was detected at the output. Crystalline plates can be used to form the distribution of a continuous flat light field in the implementation of a real 3D scene, which can provide a three-dimensional image on a television screen, as well as on a computer monitor screen. It can also be used in billboards. The three-dimensional image obtained in this way can be observed directly with the eyes of a person (without using special glasses. Thus, the information capacity of the image on the screen increases, and the perception of the picture approaches real conditions.


Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3510
Author(s):  
Liang Qi ◽  
Linas Minkevičius ◽  
Andrzej Urbanowicz ◽  
Andrej Švigelj ◽  
Ignas Grigelionis ◽  
...  

An ability of lensless titanium-based antenna coupled microbolometers (Ti-μbolometers) operating at room temperature to monitor precisely radiation patterns in terahertz time-domain spectroscopy (THz-TDS) systems are demonstrated. To provide comprehensive picture, two different THz-TDS systems and Ti-μbolometers coupled with three different antennas—narrowband dipole antennas for 0.3 THz, 0.7 THz and a log-periodic antenna for wideband detection—were selected for experiments. Radiation patterns, spatial beam profiles and explicit beam evolution along the propagation axis are investigated; polarization-sensitive properties under various THz emitter power ranges are revealed. It was found that the studied Ti-μbolometers are convenient lensless sensors suitable to discriminate and control THz radiation pattern features in various wideband THz-TDS systems.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jonathan K. Kleen ◽  
Jason E. Chung ◽  
Kristin K. Sellers ◽  
Jenny Zhou ◽  
Michael Triplett ◽  
...  

AbstractThe hippocampus is diversely interconnected with other brain systems along its axis. Cycles of theta-frequency activity are believed to propagate from the septal to temporal pole, yet it is unclear how this one-way route supports the flexible cognitive capacities of this structure. We leveraged novel thin-film microgrid arrays conformed to the human hippocampal surface to track neural activity two-dimensionally in vivo. All oscillation frequencies identified between 1–15 Hz propagated across the tissue. Moreover, they dynamically shifted between two roughly opposite directions oblique to the long axis. This predominant propagation axis was mirrored across participants, hemispheres, and consciousness states. Directionality was modulated in a participant who performed a behavioral task, and it could be predicted by wave amplitude topography over the hippocampal surface. Our results show that propagation directions may thus represent distinct meso-scale network computations, operating along versatile spatiotemporal processing routes across the hippocampal body.


2021 ◽  
Vol 29 (4) ◽  
pp. 5487
Author(s):  
Andong Wang ◽  
Lan Jiang ◽  
Xiaowei Li ◽  
Ji Huang ◽  
Zhijie Xu ◽  
...  

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