Let us consider a simple example that most readers may be familiar with: a UNIVERSITY database for maintaining information concerning students, courses, and grades in a university environment. Figure shows the database structure and a few sample data for such a database. The database is organized as five files, each of which stores data records
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Databases and database technology have a major impact on the growing use of computers. It is fair to say that databases play a critical role in almost all areas where computers are used, including business, electronic commerce, engineering, medicine, genetics, law, education, and library science. The word database is so commonly used that we must
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Step 1 : The delivery valve is closed and the suction pipe, casing and portion of the delivery pipe up to the delivery valve are completely filled with the liquid so that no air pocket is left. This process is called priming a Centrifugal Pump. Step 2 : The electric motor is started to rotate
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Centrifugal pumps are the devices which convert the mechanical energy into hydraulic energy by means of centrifugal force acting on the fluid. Centrifugal pumps are classified as roto dynamic type of pumps in which a dynamic pressure is developed to lift liquids from lower level to higher level. The basic working principle of centrifugal pump
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In a double acting reciprocating pump, the suction and delivery strokes occur simultaneously. When the crank rotates from IDC to ODC, a vacuum is created on the left side of the piston and the liquid is sucked from the sump through suction valve S1. At the same time, the liquid on the right side of
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In a single acting reciprocating pumps, liquid acts on one side of the piston only. Image shows a single acting reciprocating pump which has one suction pipe and one delivery pipe. It is usually placed above the liquid level in the sump. When the crank rotates clockwise from dead centre (IDC) (from A) to outer
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The reciprocating pumps is a positive displacement pump. It operates on the principle of actual displacement or pushing the liquid by a piston or plunger that reciprocates in a closely fitting cylinder. These pumps usually have one or more cylinders which are alternatively filled with liquid to be pumped and then emptied again. In this
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There are two methods of dimensional analysis used. Rayleigh’s method Buckingham π-Theorem Rayleigh’s Method In Rayleigh’s method, the expression is determined for a variable depending upon maximum three or four variables only. If the number of independent variables becomes more than four, it is very difficult to find the expression for the dependent variable. So,
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One dimensional flow is the type of flow in which the flow characteristics such as velocity, pressure, density, temperature etc. are the function of time and one space co-ordinate only. Mathematically, u=f(x) ; v=0 ; w=0… for steady flow u=f(x) ; v=0 ; w=0… for unsteady flow where u, v and w are velocity components
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Most of the conventional pressure gauges are of a mechanical type. These gauges embody on elastic element which deflects under the action of the applied pressure. This movement mechanically magnified and read with the help of pointer and graduated scale. These pressure gauges are generally used for measuring high pressures and where the high precision
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