Determination of the Effective Depth for Double-Fiber Fluorometric Sensors

1992 ◽  
Vol 46 (6) ◽  
pp. 919-924 ◽  
Author(s):  
Zhong Yuan Zhu ◽  
M. Cecilia Yappert
Keyword(s):  
Fiber Optic Sensor ◽  
Fluorescence Signal ◽  
Acceptance Angle ◽  
Fiber Sensors ◽  
Sample Depth ◽  
Effective Depth ◽  
Different Diameters ◽  
Semi Empirical ◽  
Analytical Expressions

The relationship between the relative fluorescence signal excited and collected with a double-fiber optic sensor and the sample depth has been investigated. The complexity of the analytical expressions for the relative fluorescence signal and the effective depth was reduced by deriving a set of semi-empirical equations which can be evaluated in a simple fashion. These expressions take into account the configuration of the sensor, i.e., fiber diameter, acceptance angle, and separation between fibers. The expressions were tested with the use of double-fiber sensors with different diameters and separations between fibers. The reduction of the effective depth in solutions with significant absorbance was evaluated.

Determination of Effective Depth and Equivalent Pathlength for a Single-Fiber Fluorometric Sensor

1992 ◽  
Vol 46 (6) ◽  
pp. 912-918 ◽  
Author(s):  
Zhong Yuan Zhu ◽  
M. Cecilia Yappert
Keyword(s):  
Single Fiber ◽  
Fluorescence Signal ◽  
Acceptance Angle ◽  
Sample Depth ◽  
Total Fluorescence ◽  
Effective Depth ◽  
Fluorometric Sensor ◽  
The Relationship ◽  
Fiber Radius

The relationship between sample depth and the corresponding fluorescence signal excited and collected with a single-fiber fluorometric optical sensor has been theoretically derived. The effective depth, zeff, is defined as the sample depth from which 90% of the total fluorescence signal originates. This parameter can be theoretically predicted as a function of the fiber radius, r0, the acceptance angle, α, and the sample absorbance. For solutions of negligible absorbance, the effective depth is zeff = 9 r0 tan−1α. The theoretical expressions have been experimentally tested with the use of 100- and 200-μm-core fibers and Rhodamine 6G solutions of different absorbances.

Diagnostics of the location of damage to tubing oil well pipes

2019 ◽  
Vol 5 (4) ◽  
pp. 115-128
Author(s):  
Timur A. Ishmuratov ◽  
Rif G. Sultanov ◽  
Milyausha N. Khusnutdinova
Keyword(s):  
Fluid Motion ◽  
Oil Well ◽  
General Belief ◽  
Oil Flow ◽  
Specialized Equipment ◽  
Improving Accuracy ◽  
Analytical Expressions ◽  
Technical Measures ◽  
Quick Determination

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.

A New Approach for Erosion Prediction Due To Fly Ash

1981 ◽  
Vol 103 (2) ◽  
pp. 265-270 ◽  
Author(s):  
R. Kotwal ◽  
W. Tabakoff
Keyword(s):  
Fly Ash ◽  
Gas Turbines ◽  
Precise Determination ◽  
Erosion Prediction ◽  
Industrial Gas Turbines ◽  
Series Of Experiments ◽  
A New Technique ◽  
Nickel Base ◽  
Semi Empirical

With increasing interest in the burning of coal in industrial gas turbines, there is also concern for the precise determination of the erosive effects on the turbine components. Series of experiments were conducted to determine the effects of fly ash constituents, particle size, particle velocity, angle of attack and target temperature on the erosion of iron and nickel base alloys. Based on the experimental results, a semi-empirical equation has been obtained for the prediction of the erosion losses. This equation provides a new technique for predicting the metal erosion due to the fly ash produced by the conventional burning of coal.

scholarly journals Analytical Expressions of Hydro-Seismic Forces on Dams

2018 ◽  
Author(s):  
Abdelmadjid Tadjadit ◽  
Boualem Tiliouine
Keyword(s):  
Viscous Fluid ◽  
Linear Combination ◽  
Upstream Face ◽  
Compressible Viscous Fluid ◽  
Natural Modes ◽  
Boundary Method ◽  
Complete Sets ◽  
Seismic Forces ◽  
Analytical Expressions

Analytical expressions for the determination of hydro-seismic forces acting on a rigid dam with irregular upstream face geometry in presence of a compressible viscous fluid are derived through a linear combination of the natural modes of water in the reservoir based on a boundary method making use of complete sets of complex T-functions.Analytical expressions for the determination of hydro-seismic forces acting on a rigid dam with irregular upstream face geometry in presence of a compressible viscous fluid are derived through a linear combination of the natural modes of water in the reservoir based on a boundary method making use of complete sets of complex T-functions. The formulas obtained for distributions of both shear forces and overturning moments are simple, computationally effective and useful for the preliminary design of dams. They show clearly the separate and combined effects of compressibility and viscosity of water. They also have the advantage of being able to cover a wide range of excitation frequencies even beyond the cut-off frequencies of the natural modes of the reservoir. Key results obtained using the proposed analytical expressions of the hydrodynamic forces are validated using numerical and experimental solutions published for some particular cases available in the specialized literature.

scholarly journals Fiber-Optic Sensor with a Dye-Modified Chitosan/Poly(vinyl alcohol) Cladding for the Determination of Organic Acids.

1996 ◽  
Vol 12 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Yoshiaki KURAUCHI ◽  
Tohru OGATA ◽  
Naoyoshi EGASHIRA ◽  
Kazuya OHGA
Keyword(s):  
Organic Acids ◽  
Vinyl Alcohol ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Poly Vinyl Alcohol ◽  
Modified Chitosan ◽  
Optic Sensor

Semi-empirical determination of the long-range molecular states dissociating to C(3PJ)+O(3PJ′)

1989 ◽  
Vol 134 (1) ◽  
pp. 7-18 ◽  
Author(s):  
B. Bussery ◽  
M.E. Rosenkrantz ◽  
D.D. Konowalow ◽  
M. Aubert-frécon
Keyword(s):  
Long Range ◽  
Empirical Determination ◽  
Semi Empirical
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