Conditions for transition from a plume to a dome above a heated horizontal area

2020 ◽  
Vol 156 ◽  
pp. 119868 ◽  
Author(s):  
Yifan Fan ◽  
Qun Wang ◽  
Jian Ge ◽  
Yuguo Li
Keyword(s):  
Horizontal Area

A NEW METHOD OF PATTERN SHOOTING

Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 539-564 ◽  
Author(s):  
J. O. Parr ◽  
W. H. Mayne
Keyword(s):  
Finite Number ◽  
Finite Length ◽  
Vertical Line ◽  
New Method ◽  
Horizontal Line ◽  
Wavelength Band ◽  
Continuous Band ◽  
Reversed Polarity ◽  
Multiple Detectors ◽  
Horizontal Area

In areas where reflection shooting is difficult, it is often necessary to attenuate the energy in a broad continuous band of disturbing wavelengths to less than a few hundredths of what would be recorded if all units were bunched together. The wavelength band of the attenuated energy should be adjacent to the band of reflection wavelengths received. Attenuation of the undesired energy is best accomplished with multiple detectors or charges. In many areas the pattern should attenuate energy horizontally propagated in all directions, not just in the direction of the detector line. Neither a finite number of uniformly effective, uniformly spaced units in line nor a uniformly effective sheet of finite length will accomplish this result. A system for gradation of the effectiveness of units described in this paper does produce this result (not only for in‐line disturbances but also for disturbances coming in from the side of the line). The attenuation band can be made broad with good attenuation or narrower with still better attenuation, as desired. The variation of effectiveness can be applied to detectors or charges arranged in a horizontal line, over a horizontal area, in a vertical line, or over a vertical area. The principle of varying effectiveness can also be applied to reversed‐polarity detectors in order to accentuate certain apparent wavelengths.

scholarly journals Magnitude-frequency of sea cliff instabilities

2008 ◽  
Vol 8 (5) ◽  
pp. 1161-1171 ◽  
Author(s):  
F. M. S. F. Marques
Keyword(s):  
Hazard Assessment ◽  
Spatial Scales ◽  
Power Laws ◽  
Inverse Power ◽  
Frequency Relationship ◽  
Relationship Of ◽  
Sea Cliff ◽  
Hazard Components ◽  
Cliff Retreat ◽  
Horizontal Area

Abstract. The magnitude-frequency relationship of sea cliff failures in strong, low retreat rate cliffs, was studied using systematic historical inventories carried out in the coasts of Portugal and Morocco, in different geological and geomorphological settings, covering a wide size scale, from small to comparatively large rockslides, topples and rockfalls, at different time and spatial scales. The magnitude-frequency expressed in terms of volume displaced and of horizontal area lost at the cliff top showed good fit by inverse power laws of the type p=a.x−b, with a values from 0.2 to 0.3, and exponents b close to 1.0, similar to those proposed for rockfall inventories. The proposed power laws address the magnitude-frequency for sea cliff failures, which is an important component of hazard assessment, to be completed with adequate models for space and time hazard components. Maximum local retreat at the cliff top provided acceptable fitting to inverse power laws only for failures wider than 2m, with a = 4.0, and exponent b = 2.3, which may be useful to assess the cliff retreat hazard for the use of areas located near the cliff top.

scholarly journals THE DISSIPATION OF WAVE ENERGY BY TURBULENCE

1980 ◽  
Vol 1 (17) ◽  
pp. 52
Author(s):  
Yu Kuang-ming
Keyword(s):  
General Theory ◽  
Wave Energy ◽  
Laboratory Experiments ◽  
Velocity Fields ◽  
Mixing Length ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
The Mean ◽  
Vertical Gradients ◽  
Horizontal Area

This paper first gives a brief review of the existing research works on the laws governing the dissipation of rave energy by turbulence. Starting from the general theory of turbulent motion and the writer's suggestion in regard to the mixing length of water particles in two-dimensional flow and making use of the principle of dimensional analysis and the trochidal rave theory, a formula has been derived to compute the mean dissipation per unit time and per unit horizontal area of wave energy due to turbulence. The formula takes the horizontal and vertical gradients of both the horizontal and vertical velocity fields into consideration. Coefficient in the formula has been determined through laboratory experiments.

Elongation and Enclosure

2005 ◽  
Vol 101 (1) ◽  
pp. 303-308 ◽  
Author(s):  
Arthur E. Stamps
Keyword(s):  
Elongation Ratio ◽  
Order Of Magnitude ◽  
Ratio Range ◽  
Horizontal Area

Previous work suggested that elongation, horizontal area, and the boundary material might influence impressions of enclosure. This article describes an experiment in which these three factors were crossed. Ratings of open/enclosed by 15 respondents on 16 plazas indicated that the elongation ratio (range: 1:1 up to 1:1.8) had the strongest effect on impressions of enclosure (18% of variance). Horizontal area (12.25 m2 vs 49 m2) area accounted for 3% of variance. The amount of variance attributable to boundary material (plants vs walls) was an order of magnitude smaller (0.3%).

EXPERIMENTAL INVESTIGATION OF THE NM-64 NEUTRON MONITOR

1964 ◽  
Vol 42 (12) ◽  
pp. 2443-2472 ◽  
Author(s):  
C. J. Hatton ◽  
H. Carimichael
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Neutron Monitor ◽  
Counting Rate ◽  
Gas Pressure ◽  
Thermal Neutrons ◽  
Horizontal Area

A comprehensive experimental study has been made of the NM-64 neutron monitor. The counting rate has been measured as a function of the thickness of the reflector, of the separation of the counters, of the thickness of the inner moderator, and of the gas pressure in the counters. It is shown that the figures given in the internationally approved specification represent a satisfactory optimization of the design. The counting rate of the NM-64 monitor is found to be 3.3 times that of an IGY monitor of the same horizontal area. The origin and movement of both fast and thermal neutrons within the monitor have been investigated using cadmium sheets and by studying events producing counts in more than one counter.

scholarly journals Redistribution process of precipitation in ecological restoration activity of Pinus sylvestris  var. mongolica in Mu Us Sandy Land, China

2021 ◽  
Author(s):  
Yiben Cheng ◽  
Hongbin Zhan ◽  
Wenbin Yang ◽  
Yunqi Wang ◽  
Qunou Jiang ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Soil Water ◽  
Sap Flow ◽  
Arid Regions ◽  
Moisture Distribution ◽  
Sandy Land ◽  
Mu Us Sandy Land ◽  
Shallow Soil ◽  
Semi Arid ◽  
Horizontal Area

Abstract. Precipitation was the most important water resource in semi-arid regions of China. The redistribution of precipitation among atmospheric water, soil water and groundwater are related to the land surface ecological system sustainability. The study took widely replanted Pinus sylvestris var. mongolica (PSM) in Mu Us Sandy Land (MUSL) as a research object and monitored precipitation, soil moisture, sap flow, and deep soil recharge (DSR) to find out moisture distribution in shallow soil layer. Results showed that the restoration process of PSM in MUSL changed the distribution of precipitation. Precipitation was intercepted in shallow soil, evapotranspiration increased, and DSR significantly decreased, resulting in up to 466.94 mm of precipitation returning to the atmosphere through evapotranspiration in 2016. Vegetation increased soil water storage (SWS) capacity, with maximum SWS in PSM plot and bare sandy land (BSL) being 260 mm and 197 mm per unit horizontal area, respectively in 2016. DSR decreased from 54.03 % of precipitation in BSL to 0.2 % of precipitation in PSM in 2016. Infiltration was not only intercepted by PSM ecosystem, resulting in a time lag, but was also affected by soil temperature, and the infiltration rate in the BSL plot was 11 times of that in the PSM plot from August to September in an annual base. SWS decreased 16 mm and 7.58 mm per unit horizontal area over a one-year period (from March to October) in 2017 and 2019, respectively. The PSM annual sap flow was maintained at a relatively constant level of 153.98 mm/yr. This study helps understand the role of precipitation-induced groundwater recharge in the process of vegetation restoration in semi-arid regions and explains the possible causes of PSM forest degradation. It is necessary to reduce PSM density to allow adaptation to extreme drought in the future.

scholarly journals ON THE OVERLAND FLOW OF TSUNAMI AND EFFECTIVENESS OF WALL AS A COUNTER MEASURE

1968 ◽  
Vol 1 (11) ◽  
pp. 58 ◽  
Author(s):  
Toshio Iwasaki ◽  
Hiroyoshi Togashi
Keyword(s):  
Overland Flow ◽  
Vertical Wall ◽  
Large Magnitude ◽  
Populated Area ◽  
Running Water ◽  
Tsunami Waves ◽  
Public Investments ◽  
Sloping Beach ◽  
Theoretical Results ◽  
Horizontal Area

When a tsunami of large magnitude strikes a coast line, various kinds of disaster such as loss of lives, properties or public investments are caused by inundation of tsunami over nearly horizontal area. Although tsunami runup has been investigated for the sloping beach, these populated area is bordered on sea by a vertical wall such as a quaywall or a highway revetment. In this paper, transformation of tsunami waves at a vertical quaywall is analysed using U-C characteristics and overland flow is treated. Effectiveness of a vertical land dike aiming to stop running water is investigated also. Theoretical results are verified by experiments.

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