Quick determination of gas pressure before uncovering coal in cross-cuts and shafts

2008 ◽  
Vol 18 (4) ◽  
pp. 494-499 ◽  
Author(s):  
Cheng-lin JIANG ◽  
Chen WANG ◽  
Xiao-wei LI ◽  
Yu-jia CHEN ◽  
Qing-xue XIE ◽  
...  
Author(s):  
Timur A. Ishmuratov ◽  
Rif G. Sultanov ◽  
Milyausha N. Khusnutdinova

The study is devoted to the mathematical description of the process of oil outflow in places of leakage of the tubing string, which allows a computer to locate a leakage in the tubing. The authors propose methodology for identifying defects in the tubing and determining the location of the leak. The uniqueness of this methodology lies in quick determination of the place of leakage without the use of specialists, sophisticated and specialized equipment. Mathematical modeling of oil flow in the tubing requires the apparatus of continuum mechanics. It is a general belief that the movement of oil in the pipe flows at low speeds due to its outflow from the hole. Using the general equations of mass and energy balance, the authors have obtained differential equations of fluid motion in a vertical pipe in the process of its outflow from the tubing and in the process of injection. Analytical expressions are the solution to these equations, as they can help in estimating the degree of damage and its location, as well as the feasibility of its eliminating. The results show that an increase in the leakage and injection times leads to improving accuracy of locating damage. Thus, when conducting various geological and technical measures (GTM) at the well, it is possible to assess the presence of leakage and its intensity when deciding on the repair of tubing.


Author(s):  
M. A. Perinelli ◽  
N. Carugno

Abstract A flameless atomic absorption method has been developed which permits the quick determination of the levels of trace metals in cigarette smoke. The total particulate matter (TPM) was collected by electrostatic precipitation and dissolved in methanol before analysis. In order to trap the last remaining traces of metals, the gas phase was passed through microporous filters which were analysed direct. The sensitivity of this method for the metals studied (Zn, Pb, Cd, Ni) is good in both the particulate and gas phase samples, with the sole exception of Ni in the gas phase. Results obtained by the flame and flameless methods are compared.


1954 ◽  
Vol 21 (2) ◽  
pp. 178-184
Author(s):  
M. L. Baron ◽  
H. H. Bleich

Abstract Tables are presented for the quick determination of the frequencies and shapes of modes of infinitely long thin cylindrical shells. To make the problem tractable, the shells are first treated as membranes without bending stiffness, and the bending effects are introduced subsequently as corrections. The underlying theory is based on the energy expressions for cylindrical shells. The tables cover the following range: lengths of longitudinal half wave L from 1 to 10 radii a; number n of circumferential waves from 0 to 6. The results apply for Poisson’s ratio ν = 0.30.


1999 ◽  
Vol 5 (4) ◽  
pp. 387-398
Author(s):  
R.M. Frey ◽  
F.H. Wittmann

Abstract In many cases there is a risk for the formation of blisters if impermeable polymer coatings are applied on porous substrates. On covers of courses in sport stadiums formation of blisters has been observed recently. In this contribution a method is described which can be used to investigate the causes of blister formation in a given system. Blisters are artificially created by the application of a gas pressure in the interface between coating and substrate. In this way the growth of blisters can be varied under controlled conditions. The theoretical background of this method is outlined. In this way it is possible to estimate the necessary pressure under the cover to create blisters of the observed size.


2017 ◽  
Vol 45 ◽  
pp. 502-510 ◽  
Author(s):  
Chaojie Wang ◽  
Shengqiang Yang ◽  
Chenglin Jiang ◽  
Dingding Yang ◽  
Chaojie Zhang ◽  
...  

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