A SCALE MODEL STUDY ON THE DEFORMATION AROUND THE DRIFT IN KOREAN INCLINED COAL SEAM

1988 ◽  
pp. 199-206
Author(s):  
LEE KYUNG–WON ◽  
KIM MIN–KUE
Keyword(s):  
Coal Seam ◽  
Scale Model ◽  
Model Study

scholarly journals THE EFFECT OF WAVE DIRECTION ON SHIP MOTIONS IN A HARBOUR ENTRANCE CHANNEL - MODEL STUDY APPROACH

1984 ◽  
Vol 1 (19) ◽  
pp. 217
Author(s):  
A.C. Van Wyk ◽  
J.A. Zwamborn
Keyword(s):  
Channel Model ◽  
Basic Knowledge ◽  
Scale Model ◽  
Ship Motions ◽  
Wave Direction ◽  
Extreme Wave ◽  
Essential Requirement ◽  
Study Approach ◽  
Model Study ◽  
Bulk Carriers

Basic knowledge of a ship's vertical motions in waves of different angles of approach is an essential requirement in the formulation of allowance criteria on which to base harbour accessibility under extreme wave conditions. A comprehensive series of scale model tests are being undertaken to establish minimum underkeel clearance for given channel depths and sea states using two models representing typical 150 000 and 270 000 dwt bulk carriers.

scholarly journals A Scale Model Study of the Bosomtwe Crater.

1965 ◽  
Vol 70 ◽  
pp. 324
Author(s):  
G. H. S. Jones ◽  
C. H. H. Diehl
Keyword(s):  
Scale Model ◽  
Model Study

scholarly journals Fully Coupled Multi-Scale Model for Gas Extraction from Coal Seam Stimulated by Directional Hydraulic Fracturing

2019 ◽  
Vol 9 (21) ◽  
pp. 4720 ◽  
Author(s):  
Ge ◽  
Zhang ◽  
Sun ◽  
Hu
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Scale Model ◽  
Gas Extraction ◽  
Coal Seams ◽  
Directional Hydraulic Fracturing ◽  
Coal Mine Methane ◽  
Multi Scale ◽  
Fully Coupled

Although numerous studies have tried to explain the mechanism of directional hydraulic fracturing in a coal seam, few of them have been conducted on gas migration stimulated by directional hydraulic fracturing during coal mine methane extraction. In this study, a fully coupled multi-scale model to stimulate gas extraction from a coal seam stimulated by directional hydraulic fracturing was developed and calculated by a finite element approach. The model considers gas flow and heat transfer within the hydraulic fractures, the coal matrix, and cleat system, and it accounts for coal deformation. The model was verified using gas amount data from the NO.8 coal seam at Fengchun mine, Chongqing, Southwest China. Model simulation results show that slots and hydraulic fracture can expand the area of gas pressure drop and decrease the time needed to complete the extraction. The evolution of hydraulic fracture apertures and permeability in coal seams is greatly influenced by the effective stress and coal matrix deformation. A series of sensitivity analyses were performed to investigate the impacts of key factors on gas extraction time of completion. The study shows that hydraulic fracture aperture and the cleat permeability of coal seams play crucial roles in gas extraction from a coal seam stimulated by directional hydraulic fracturing. In addition, the reasonable arrangement of directional boreholes could improve the gas extraction efficiency. A large coal seam dip angle and high temperature help to enhance coal mine methane extraction from the coal seam.

Reduced-scale model study on cable heat dissipation and airflow distribution of power cabins

2019 ◽  
Vol 160 ◽  
pp. 114068 ◽  
Author(s):  
Jiaxu Wang ◽  
Xuefeng Liu ◽  
Siwei Chen ◽  
Hanghang Jiang ◽  
Guanyu Fang ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Scale Model ◽  
Model Study ◽  
Airflow Distribution ◽  
Distribution Of Power ◽  
Reduced Scale

Acoustical scale model study of the attenuation of sound by wide barriers

1977 ◽  
Vol 62 (3) ◽  
pp. 601-606 ◽  
Author(s):  
Elizabeth S. Ivey ◽  
G. A. Russell
Keyword(s):  
Scale Model ◽  
Model Study

scholarly journals Impacts of climate and emission changes on nitrogen deposition in Europe: a multi-model study

2014 ◽  
Vol 14 (5) ◽  
pp. 6663-6720 ◽  
Author(s):  
D. Simpson ◽  
C. Andersson ◽  
J.H. Christensen ◽  
M. Engardt ◽  
C. Geels ◽  
...  
Keyword(s):  
Critical Loads ◽  
N Deposition ◽  
Scale Model ◽  
Gaseous Ammonia ◽  
Nh3 Emission ◽  
Model Study ◽  
Emission Changes ◽  
Emission Change ◽  
The Impact ◽  
Oxidised Nitrogen

Abstract. The impact of climate and emissions changes on the deposition of reactive nitrogen (Nr) over Europe was studied using four offline regional chemistry transport models (CTMs) driven by the same global projection of future climate over the period 2000–2050. Anthropogenic emissions for the years 2005 and 2050 were used for simulations of both present and future periods in order to isolate the impact of climate change, hemispheric boundary conditions and emissions, and to assess the robustness of the result across the different models. The results from these four CTMs clearly show that the main driver of future N-deposition changes is the specified emission change. Under the specified emission scenario for 2050, emissions of oxidised nitrogen were reduced substantially, whereas emissions of NH3 increase to some extent, and these changes are largely reflected in the modelled concentrations and depositions. The lack of sulphur and oxidised nitrogen in the future atmosphere results in a much larger fraction of NHx being present in the form of gaseous ammonia. Predictions for wet and total deposition were broadly consistent, although the three fine-scale models resolve European emission areas and changes better than the hemispheric-scale model. The biggest difference in the models is for predictions of individual N-compounds. One model (EMEP) was used to explore changes in critical loads, also in conjunction with speculative climate-induced increases in NH3 emissions. These calculations suggest that the area of ecosystems which exceed critical loads is reduced from 64% for year 2005 emissions levels to 50% for currently estimated 2050 levels. A possible climate-induced increase in NH3 emissions could worsen the situation, with areas exceeded increasing again to 57% (for a 30% NH3 emission increase).

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