The Application of Optimized GM(1,1) in Mine Gas Flow Volume Forecast

2011 ◽  
Author(s):  
Zhang TianJun ◽  
Su Lin ◽  
Qiao BaoMing ◽  
Ma Mina
Keyword(s):  
Gas Flow ◽  
Flow Volume ◽  
Mine Gas

Mine Gas Flow in the Porous Massif and CFD Tool

2015 ◽  
Vol 362 ◽  
pp. 38-46
Author(s):  
Pavel Staša ◽  
Oldřich Kodym
Keyword(s):  
Rock Mass ◽  
Gas Flow ◽  
Mining Activity ◽  
Flow Modeling ◽  
Coal Seams ◽  
The Past ◽  
Mining Conditions ◽  
Reduce Risk ◽  
Mine Gas ◽  
Numerical Flow Modeling

There is a still dangerous effect in the form of methane leakage from coal seams in areas where mining activity still continuing or took place in the past. The issue of mining gas flow is still a matter that is necessary to pay attention and try to find new ways to solve this set of phenomena, no matter if it is the mining corridors or the flow in the rock massif. The number of measures to gradually reduce risk has been taken to protect the population. Nevertheless, the current situation is generally rated as serious as those risks still remain valid. Leakage of mine gases depend on many natural and technical mining conditions. With the closure of mines and thus the end of the ventilation situation considerably worse. This paper deals with the flow of dangerous mine gas, methane, through the rock mass using numerical flow modeling using CFD program Fluent. Using CFD codes can gain insight on the phenomenon under review and the results to take appropriate measures in the form of active or passive intervention.

scholarly journals Veress needle insertion in the left hypochondrium in creation of the pneumoperitoneum

2006 ◽  
Vol 21 (5) ◽  
pp. 296-303 ◽  
Author(s):  
Otávio Cansanção de Azevedo ◽  
João Luiz Moreira Coutinho Azevedo ◽  
Albino Augusto Sorbello ◽  
Gustavo Peixoto Soares Miguel ◽  
Rodrigo Santa Cruz Guindalini ◽  
...  
Keyword(s):  
Peritoneal Cavity ◽  
Gas Flow ◽  
Needle Insertion ◽  
Veress Needle ◽  
Flow Volume ◽  
Intraperitoneal Pressure ◽  
Alternative Method ◽  
Left Hypochondrium ◽  
The Creation ◽  
Positive Results

PURPOSE: To test the efficacy of the puncture in the left hypochondrium as an alternative method. METHODS: Sixty-two patients randomly distributed into two groups were studied: Group LH, puncture in the left hypochondrium (n=30), and Group ML, puncture in the abdominal midline (n=32). The following were assessed: needle positioning tests, number of failed attempts at needle insertion, and time needed for creation of pneumoperitoneum. Gas flow, volume and intraperitoneal pressure were recorded at every 20 seconds, until a 12 mmHg pressure was reached inside the peritoneal cavity. RESULTS: A similar number of positive results for the needle positioning tests were observed in both groups. Two failed attempts to reach the peritoneal cavity were observed in Group ML and one in Group LH. The time necessary for the creation of pneumoperitoneum was on average 3 minutes and 46 seconds for Group LH, and 4 minutes and 2 seconds for Group ML. Average gas flow, volume and pressure were equivalent for both groups. CONCLUSION: Puncture in the left hypochondrium was as effective as puncture in the abdominal midline for the creation of pneumoperitoneum.

scholarly journals Regularity of Mine Gas Flow Disaster Induced by Gas Natural Ventilation Pressure after Coal and Gas Outbursts

ACS Omega ◽  
2021 ◽  
Author(s):  
Jingxiao Yu ◽  
Zongxiang Li ◽  
Yu Liu ◽  
Ziwen Dong ◽  
Yashengnan Sun
Keyword(s):  
Gas Flow ◽  
Natural Ventilation ◽  
Coal And Gas Outbursts ◽  
Mine Gas

Effects of Immersion in Water and Changes in Intrathoracic Blood Volume on Lung Function in Man

1976 ◽  
Vol 51 (3) ◽  
pp. 303-311
Author(s):  
N. K. Burki
Keyword(s):  
Hydrostatic Pressure ◽  
Blood Volume ◽  
Gas Flow ◽  
Water Immersion ◽  
Normal Subjects ◽  
Venous Occlusion ◽  
Intrathoracic Blood Volume ◽  
Closing Volume ◽  
Flow Volume ◽  
Pulmonary Compliance

1. In healthy, normal subjects simultaneous peripheral venous occlusion of all four limbs caused a small but significant increase in vital capacity (VC) and single-breath carbon monoxide transfer factor (DLCO) without significantly changing total lung capacity (TLC), residual volume (RV), pulmonary gas flow or pulmonary compliance. 2. Immersion in water to the neck resulted in a small but significant fall in VC, FEV1.0/FVC and TLC, and a rise in DLCO, but flow/volume curves and ‘closing volume’ were unchanged. Peripheral venous occlusion during immersion only significantly increased VC and DLCO; pulmonary compliance and flow/volume curves did not alter significantly. 3. It is concluded that peripheral venous occlusion produces these effects by altering intrathoracic blood volume. Water immersion reduces TLC, mainly from the hydrostatic pressure, and VC is reduced from both the hydrostatic pressure and the increase in intrathoracic blood volume consequent on immersion. The increase in DLCO is due, almost entirely, to the increase in intrathoracic blood volume.

TEM evaluation of graded SixGe1-x heterolayers

1991 ◽  
Vol 49 ◽  
pp. 894-895
Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Gas Flow ◽  
Field Effect Transistors ◽  
Chemical Vapor ◽  
Dark Field ◽  
Bipolar Transistors ◽  
Structural Quality ◽  
Weak Beam ◽  
Transmission Electron ◽  
And Behavior

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.

Electron Microscopy/Diffraction Study of the Ternary Mn-Er-S System

1990 ◽  
Vol 48 (1) ◽  
pp. 76-77
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde
Keyword(s):  
Electron Microscopy ◽  
Gas Flow ◽  
Graphite Crucible ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Alumina Crucible ◽  
X Ray ◽  
Intermediate Phases ◽  
Twin Band ◽  
Ar Gas

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.

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