Spatial distribution of high-frequency spectral decay factor kappa (κ) for Delhi, India

2021 ◽  
Author(s):  
Himanshu Mittal ◽  
Babita Sharma ◽  
Manisha Sandhu ◽  
Dinesh Kumar
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Decay Factor

Modern and Holocene microbial mats and associated microbially induced sedimentary structures (MISS) on the southeastern coast of Tunisia (Mediterranean Sea)

2020 ◽  
pp. 1-21
Author(s):  
Rached Lakhdar ◽  
Mohamed Soussi ◽  
Rachida Talbi
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Depositional Environment ◽  
Microbial Mats ◽  
Coastal Environment ◽  
Tidal Dynamics ◽  
Very High Frequency ◽  
Intertidal Zones ◽  
Sedimentary Structures ◽  
Very High

Abstract On the southeastern Tunisian coastline, very diverse living microbial mats colonize the lower supratidal and intertidal zones, and locally may extend into the upper infratidal zone. The interaction between the benthic cyanobacteria and their siliciclastic substratum leads to the development of several types of microbially induced sedimentary structures (MISS). The mapping of the microbial mats has allowed the identification of the types of MISS that characterize the different segments of the coastal environment. The modern microbial mats have been compared with those recorded at the top of the Holocene deposits, which are composed of biodegraded microbial black mats alternating with white laminae made of clastic and evaporitic sediments, indicative of very high frequency cycles of flood and drought. A hypothetic profile showing their occurrences along the different areas bordering the coastline is proposed as a guide for the reconstruction of the ancient depositional environment. The roles of tidal dynamics, storms, and climate in controlling their genesis and spatial distribution, are discussed and highlighted. The modern MISS of southeastern Tunisia are compared with their equivalents that are well documented through the different geological eras.

scholarly journals Features of the Surface and Subsurface Waves Application for Ultrasonic Evaluation of Physicomechanical Properties of Solids. Part 2. Strenghtned Inhomogeneous Surface Layer

2019 ◽  
Vol 10 (1) ◽  
pp. 69-79
Author(s):  
A. R. Baev ◽  
A. L Mayorov ◽  
N. V. Levkovich ◽  
M. V. Asadchaya
Keyword(s):  
Experimental Data ◽  
Surface Layer ◽  
Spatial Distribution ◽  
Surface Wave ◽  
High Frequency ◽  
Hardened Layer ◽  
Gray Iron ◽  
Physicomechanical Properties ◽  
Inhomogeneous Surface ◽  
Ultrasonic Evaluation

The propagation of a pulsed signal of a surface wave over an object with a non-uniform surface layer, obtained, for example, as a result of surface hardening, with structural damage, is accompanied by the dispersion of the velocity of the wave carrying important information about the parameters of such a layer. The aim of the work is to study the relationship between the acoustic parameters of a pulsed acoustic signal of a surface and subsurface waves and the surface layer of steel specimens hardened by high-frequency hardening, and gray iron-chill. Features of the surface and subsurface waves application for ultrasonic evaluation of physicomechanical properties of solids. Strenghtned inhomogeneous surface layer.A brief analysis of the known works on determining the depth of hardened surface layers by various methods, including high-frequency hardening, cementation, etc., is carried out. Based on the Oulder integral expression. The dependence connecting the wave velocity, its frequency, the depth of the hardened layer and the spatial distribution of hardness represented as a step with a changing slope of its side surface simulating the transition zone of the hardened layer are calculated.Using the pulse method and low-aperture transducers with a frequency of 1−3.8 MHz, the dependences of the surface wave velocity on the cutting height of a layer hardened by HDTV hardening are obtained. A comparison of experimental data and calculations of the theoretical model showed a good qualitative correspondence between them, demonstrate a high «sensitivity» of the method in relation to the nature of the change in hardness over the depth of the hardened layer. It is shown that the proposed approach is promising for solving the inverse problem of restoring the spatial distribution of hardness based on experimental data.The goniometric method was approbated to determine the dependence between amplitude-angle characteristics and depth of the surface steel layers hardened by high-frequency hardening and depth of hardened gray iron specimens layer – with chill. It is shown that the optimal angle corresponding maximum of excited surface wave amplitude in steel specimens is decreasing up to 24–26'vs. hardened depth layer. But when the tested specimens from cast iron this angle decreasing is nearly of 6°. Recommendations on the use of research results in practice are given.

Spatial distribution of high-frequency energy radiation on the fault of the 1995 Hyogo-Ken Nanbu, Japan, earthquake (MW 6.9) on the basis of the seismogram envelope inversion

1999 ◽  
Vol 89 (1) ◽  
pp. 22-35 ◽  
Author(s):  
Hisashi Nakahara ◽  
Haruo Sato ◽  
Masakazu Ohtake ◽  
Takeshi Nishimura
Keyword(s):  
Spatial Distribution ◽  
Wave Energy ◽  
High Frequency ◽  
Fault Plane ◽  
Time Window ◽  
Source Region ◽  
Inversion Method ◽  
S Wave ◽  
Energy Radiation ◽  
Initial Rupture

Abstract We studied the generation and propagation of high-frequency (above 1 Hz) S-wave energy from the 1995 Hyogo-Ken Nanbu (Kobe), Japan, earthquake (MW 6.9) by analyzing seismogram envelopes of the mainshock and aftershocks. We first investigated the propagation characteristics of high-frequency S-wave energy in the heterogeneous lithosphere around the source region. By applying the multiple lapse time window analysis method to aftershock records, we estimated two parameters that quantitatively characterize the heterogeneity of the medium: the total scattering coefficient and the intrinsic absorption of the medium for S waves. Observed envelopes of aftershocks were well reproduced by the envelope Green functions synthesized based on the radiative transfer theory with the obtained parameters. Next, we applied the envelope inversion method to 13 strong-motion records of the mainshock. We divided the mainshock fault plane of 49 × 21 km into 21 subfaults of 7 × 7 km square and estimated the spatial distribution of the high-frequency energy radiation on that plane. The average constant rupture velocity and the duration of energy radiation for each subfault were determined by grid searching to be 3.0 km/sec and 5.0 sec, respectively. Energy radiated from the whole fault plane was estimated as 4.9 × 1014 J for 1 to 2 Hz, 3.3 × 1014 J for 2 to 4 Hz, 1.5 × 1014 J for 4 to 8 Hz, 8.9 × 1012 J for 8 to 16 Hz, and 9.8 × 1014 J in all four frequency bands. We found that strong energy was mainly radiated from three regions on the mainshock fault plane: around the initial rupture point, near the surface at Awaji Island, and a shallow portion beneath Kobe. We interpret that energetic portions were associated with rupture acceleration, a fault surface break, and rupture termination, respectively.

Spatial distribution of radiation intensity in high-frequency electrodeless discharge lamps

2000 ◽  
Vol 67 (1) ◽  
pp. 14-21 ◽  
Author(s):  
K. Yu. Nagulin ◽  
A. Kh. Gil’mutdinov ◽  
O. R. Badrutdinov
Keyword(s):  
Spatial Distribution ◽  
Radiation Intensity ◽  
High Frequency ◽  
Electrodeless Discharge

P361 Test-Retest reliability of the spatial distribution of high frequency oscillations (HFO) in intracranial EEG

2017 ◽  
Vol 128 (9) ◽  
pp. e295 ◽  
Author(s):  
Ece Boran ◽  
Sergey Burnos ◽  
Tommaso Fedele ◽  
Niklaus Krayenbühl ◽  
Peter Hilfiker ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Intracranial Eeg ◽  
Retest Reliability ◽  
High Frequency Oscillations ◽  
Test Retest Reliability

scholarly journals Application of Morishita Spread Index to temporal and spatial distribution characteristics of landslides in Shanxi and Gansu provinces of China

2000 ◽  
Vol 21 ◽  
Author(s):  
Luo Wenqiang ◽  
Zhang Zhuoyuan ◽  
Huang Runqiu
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Temporal Distribution ◽  
The Other ◽  
Distribution Characteristics ◽  
Temporal And Spatial Distribution ◽  
Landslide Occurrence ◽  
Cluster Distribution ◽  
Spatial Distribution Characteristics ◽  
Temporal And Spatial

Morshita Spread Index Iδ was applied for the study of temporal and spatial distribution characteristics of landslides in the Shanxi and Gansu provinces of China. For this purpose, the landslides larger than 105 m3 in volume were considered. In the study area, the spatial distribution of Morishita Spread Index Iδ (l) isgreater than 1 and decreases with increasing mesh scale. Such a trend indicates cluster distribution of landslides. On the other hand, the temporal distribution of Morishita Spread Index Iδ (t) for the above landslides showed a maximum and a minimum, corresponding to the years with high frequency of landslide occurrence.

scholarly journals Chaetopterus antarcticus (Polychaeta: Chaetopteridae) in Argentinian shelf scallop beds: from infaunal to epifaunal life habits

2019 ◽  
Vol 67 (S5) ◽  
pp. S39-S50
Author(s):  
Claudia S. Bremec ◽  
Laura Schejter
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Temporal Analysis ◽  
Soft Sediment ◽  
Total Absence ◽  
Tube Worms ◽  
Three Samples ◽  
Settlement Substrate ◽  
Life Habits ◽  
Selection Of

ABSTRACT. Introduction: The shelf-break frontal area in the Argentine Sea, between 37º S and 40º S, is characterized by high frequency and abundance of the parchment worm Chaetopterus antarcticus Kinberg, 1866 associated to Zygochlamys patagonica scallop beds. This polychaete was usually collected within its U tubes, typical of infaunal habit. During 2007, a surprising massive settlement of worms on scallops was observed. Objective: Our objectives is to report the variability of life habits of C. antarcticus in scallop grounds distributed between 37º S and 40º S in Argentinean waters. Methods: The presence of the parchment tube worms on Z. patagonica was analyzed in 892 scallops coming from three samples collected in September (previously obtained for other purposes) and November 2007 and April 2008, between 99-106 m depth in Management Unit B (16.186 km2, 38º S - 39º 52’ S). Polychaetes were identified and quantified on both valves. In addition, both epibiont and infaunal worms were registered through time. The settlement of C. antarcticus on scallops was monitored during the period 2007-2015 and the presence of free tubes, both empty and inhabited by worms, were registered during the period 2008-2015 from a total of 374 representative subsamples (10 l) collected with trawling tools between 37º S and 40º S. Results: Scallops collected in 2007 and 2008 showed that 468 (> 50 %) specimens were encrusted; in 66 % (311 specimens) of them C. antarcticus was settled. The temporal analysis showed that the spatial distribution of epibiotic worms decreased in 2009, 2010 and 2012, with its total absence in 2013, 2014 and 2015 in the study area. During the period 2007 - 2015, infaunal worms were registered throughout the area, collected in part of the locations monitored. Conclusions: The variability of life habits of C. antarcticus was not commonly registered previously in the study area; epibiotic behavior could be the result of intensive soft sediment disturbance due to trawling and hence, the selection of other available primary settlement substrate.

scholarly journals Spatial distribution of pressure resonance in compressible cavity flow

2018 ◽  
Vol 848 ◽  
pp. 660-675 ◽  
Author(s):  
Katya M. Casper ◽  
Justin L. Wagner ◽  
Steven J. Beresh ◽  
Russell W. Spillers ◽  
John F. Henfling ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
High Frequency ◽  
Travelling Wave ◽  
Cavity Resonance ◽  
Finite Width ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive ◽  
Oscillatory Pattern ◽  
Power Spectral ◽  
Propagating Shear

The development of the unsteady pressure field on the floor of a rectangular cavity was studied at Mach 0.9 using high-frequency pressure-sensitive paint. Power spectral amplitudes at each cavity resonance exhibit a spatial distribution with a streamwise-oscillatory pattern; additional maxima and minima appear as the mode number is increased. This spatial distribution also appears in the propagation velocity of modal pressure disturbances. This behaviour was tied to the superposition of a downstream-propagating shear-layer disturbance and an upstream-propagating acoustic wave of different amplitudes and convection velocities, consistent with the classical Rossiter model. The summation of these waves generates a net downstream-travelling wave whose amplitude and phase velocity are modulated by a fixed envelope within the cavity. This travelling-wave interpretation of the Rossiter model correctly predicts the instantaneous modal pressure behaviour in the cavity. Subtle spanwise variations in the modal pressure behaviour were also observed, which could be attributed to a shift in the resonance pattern as a result of spillage effects at the edges of the finite-width cavity.

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