Water-Hammer Attenuation With a Tapered Line

1969 ◽  
Vol 91 (3) ◽  
pp. 341-351 ◽  
Author(s):  
F. J. Tarantine ◽  
W. T. Rouleau
Keyword(s):  
Finite Length ◽  
Experimental Work ◽  
Theoretical Method ◽  
Water Hammer ◽  
Inviscid Liquid ◽  
The Given

An investigation has been made of the pressure attenuation that can be obtained through the application of a rigid tapered section located immediately upstream of a quick-closing valve or other surge-generating device. The model taken was that of an inviscid liquid flowing through the rigid tapered tube terminated by either a very long uniform line or a finite-length line and reservoir. This paper presents an outline of a theoretical method for solving the given problem, along with some practical solutions. A description and the results of experimental work performed to substantiate the theory are also included.

Noise Reduction Using Finite-Length Flexible Segments

1999 ◽  
Vol 122 (2) ◽  
pp. 94-108 ◽  
Author(s):  
Brian Chapnik ◽  
I. G. Currie
Keyword(s):  
Mathematical Model ◽  
Finite Length ◽  
Experimental Work ◽  
Acoustic Noise ◽  
Characteristic Impedance ◽  
Fluid Loading ◽  
Piping Systems ◽  
And Performance ◽  
Insertion Losses ◽  
Acoustical Energy

In this work, the reduction of acoustic noise in piping systems through the installation of finite flexible segments is explored. A mathematical model describing the relevant parameters is developed. To verify the model, experimental work is undertaken using rubber hoses as flexible segments and air as the contained fluid. The effect of the segment on propagating acoustical energy is studied in terms of its insertion loss. Both theoretical and experimental results indicate that, for light fluid loading, the flexibility of the segment is only important when significant axial shell resonances exist, or when one or both acoustical termination impedances at the ends of the segment are much larger or smaller than the characteristic impedance of the medium. Further, the model indicates that for heavier fluid loading (i.e., when the compressibility of the flexible section is significant in relation to the bulk compliance of the fluid), in addition to higher associated insertion losses, the finite length resonances become more pronounced, and performance is less sensitive to small variations in the termination impedances. [S0739-3717(00)00402-5]

Some Aerodynamic Aspects of Turbine Blade Cooling

1969 ◽  
Author(s):  
J. F. Barnes ◽  
P. M. Came
Keyword(s):  
Turbine Blade ◽  
Experimental Work ◽  
Reasonable Agreement ◽  
Theoretical Method ◽  
Turbine Blade Cooling ◽  
Pressure Losses ◽  
Blade Cooling ◽  
Turbine Efficiency ◽  
Cooling Air ◽  
Work Done

This paper is based mainly on theoretical and experimental work done as part of the research program on turbine blade cooling at the National Gas Turbine Establishment. After describing the effects of increased trailing edge thickness on turbine efficiency, the bulk of the paper is concerned with the losses caused by the cooling air. A simple theoretical method for calculating the pressure losses caused by discharging the spent coolant into the main gas stream is described and the available experimental results used for comparison. Reasonable agreement for the loss of efficiency is obtained. The results of some cascade tests on transportation cooled blades are also included.

On the Motion of a Heterogeneous Liquid, commencing from Rest with a given Motion of its Boundary

1897 ◽  
Vol 21 ◽  
pp. 119-122
Author(s):  
Lord Kelvin
Keyword(s):  
Kinetic Energy ◽  
Viscous Fluid ◽  
Incompressible Fluid ◽  
Viscous Liquid ◽  
Elastic Solid ◽  
Inviscid Liquid ◽  
The Given ◽  
The Ideal

I use the word “liquid” for brevity to denote an incompressible fluid, viscid or inviscid, but inviscid unless the contrary is expressly stated. A finite portion of liquid, viscid or inviscid, being given at rest, within a bounding vessel of any shape, whether simply or multiply continuous; let any motion be suddenly produced in some part of the boundary, or throughout the boundary, subject only to the enforced condition of unchanging volume. Every particle of the liquid will instantaneously commence moving with the determinate velocity and in the determinate direction, such that the kinetic energy of the whole is less than that of any other motion which the liquid could have with the given motion of its boundary. This proposition is true also for an incompressible elastic solid, manifestly ; (and for the ideal “ether” of Proc. R.S.E., March 7, 1890; and Art. xcix. vol. iii. of my Collected Mathematical and Physical Papers). The truth of the proposition for the case of a viscous liquid is very important in practical hydraulics. As an example of its application to inviscid and viscous fluid and to elastic solid consider an elastic jelly standing in an open rigid mould, and equal bulks of water and of an inviscid liquid in two vessels equal and similar to it. Give equal sudden motions to the three containing vessels: the instantaneous motions of the three contained substances will be the same.

Commercially Used Sulphate Binders Based on Anhydrite

2012 ◽  
Vol 598 ◽  
pp. 314-317 ◽  
Author(s):  
Dominik Gazdič ◽  
Marcela Fridrichová ◽  
Karel Dvořák
Keyword(s):  
Czech Republic ◽  
Experimental Work ◽  
Applied Research ◽  
Initial Study ◽  
Hydration Process ◽  
The Czech Republic ◽  
Know How ◽  
Binding Phase ◽  
German Producer ◽  
The Given

The work was devoted to the analysis of a commercially manufactured binder imported from Germany which is supposed to represent a natural anhydrite according to the accompanying documentation, industrially modified by hydration process activating agents. A similar analysis of the anhydrite binder commercially manufactured in Germany was carried out at the very beginning of investigation into the given problem. In the introductory study of applied research engaged in the feasibility of preparation of self-levelling mixes based on anhydrite binder, a specimen binder made by a German producer declared as a purely anhydrite binder, was analysed. However, it was found out by the analyses performed that this binder is a premium quality -gypsum according to all manifestations by a modified liquefying and retarding agent, possibly by other compounds. Due to potential changes that may have occurred since the initial study in the composition of the so-called anhydrite binders, exploration of composition of the binders currently used in the Czech Republic for preparation of self-levelling mixtures was carried out in this part of the experimental work. The exploration detected that the composition of the binding phase is the matter of know-how for the majority of companies, and as a result, the only one sample of binder has been obtained so far from the company which reserved their anonymity for this work.

Overstrain Tests on Thick-Walled Cylinders

1960 ◽  
Vol 82 (2) ◽  
pp. 103-116 ◽  
Author(s):  
S. M. Jorgensen
Keyword(s):  
Experimental Data ◽  
Strain Hardening ◽  
Experimental Work ◽  
Theoretical Method ◽  
Bursting Strength ◽  
Strength Based ◽  
Stress Levels ◽  
Simplified Formula

The experimental work described in the following covers pressure-expansion tests on thick-walled, closed-end cylinders of four different steels. The tests covered stress levels through the plastic and strain-hardening ranger to destruction, at pressures up to 100,000 psi. A theoretical method is given for computing expansion and bursting strength, based on both tension and torsion data. Finally, a simplified formula for ultimate pressures is described and checked against the experimental data.

scholarly journals Simplified approach to DFT computation for nonprogrammable scientific calculators

BIBECHANA ◽  
2014 ◽  
Vol 12 ◽  
pp. 13-19
Author(s):  
Mohd Yusuf Yasin
Keyword(s):  
Fourier Transform ◽  
Fourier Analysis ◽  
Discrete Fourier Transform ◽  
Finite Length ◽  
Taylor Series ◽  
Practical Interest ◽  
Discrete Function ◽  
Programmable Calculator ◽  
Simplified Approach ◽  
The Given

Fourier analysis is an important tool used as it is or it’s different variants in many fields of sciences and engineering. It’s importance is due to it’s simplicity with which it expands a given function in terms of circular or complex exponents. Further it is quite versatile to handle many functions of practical interest, specifically, the functions with several mathematical disabilities that are hard to be handled with tools like Taylor series. Discrete Fourier Transform (DFT) is a form of Fourier analysis where the discrete function and it’s transform are both of finite length. This processing requires lot many computations. Here in this work a simplified and non programmable calculator based scheme is presented with which one can easily determine the DFT of the given function by feeding in the DFT equation once and a few presses of the calculator keys.   DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11681BIBECHANA 12 (2015) 13-19        

Use of network educational technologies in the process of formation of information culture of junior schoolchildren

2020 ◽  
pp. 31-36
Author(s):  
Anna V. Kalinchenko ◽  
Dmitry Yu. Kalinchenko
Keyword(s):  
Experimental Research ◽  
Experimental Work ◽  
Intellectual Development ◽  
Educational Technologies ◽  
Information Culture ◽  
Theoretical Justification ◽  
Learning Methods ◽  
Methodological Basis ◽  
The Given ◽  
Educational Information

We presented theoretical and practical directions of experimental research conducted in search of mechanisms of effective formation of information culture of junior schoolchildren. We confirmed the assumption that the use of networked educational technologies played an important role in that process. The methodological basis of the theoretical justification was the provisions of didactics on the forms of providing educational information. The generalization of learning methods involves a significant expansion along with increased opportunities to use learning forms and tools. We relied on the provision that in didactics, the method of training includes the choice of a certain method, reception, means and form of training that serve to achieve the given didactic task. The construction of the method should provide the conditions for such interaction between the teacher and the student, which does not only lead the younger student to learn, but also helps him to master the ways of knowledge, contributes to his intellectual development. We presented some methods of networking and proved their effectiveness during the experimental work.

Improving Recommender Systems Using Co-Appearing and Semantically Correlated User Interests

2020 ◽  
Vol 13 (2) ◽  
pp. 240-247 ◽  
Author(s):  
Bilal Hawashin ◽  
Darah Aqel ◽  
Shadi Alzubi ◽  
Mohammad Elbes
Keyword(s):  
Recommender Systems ◽  
Experimental Work ◽  
Execution Time ◽  
Word Embeddings ◽  
User Interest ◽  
User Interests ◽  
And Behavior ◽  
The Given

Background: Recommender Systems use user interests to provide more accurate recommendations according to user actual interests and behavior. Methods: This work aims at improving recommender systems by discovering hidden user interests from the existing interests. User interest expansion would contribute in improving the accuracy of recommender systems by finding more user interests using the given ones. Two methods are proposed to perform the expansion: Expanding interests using correlated interests’ extractor and Expanding interests using word embeddings. Results: Experimental work shows that such expanding is efficient in terms of accuracy and execution time. Conclusion: Therefore, expanding user interests proved to be a promising step in the improvement of the recommender systems performance.

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