As Electrical Engineers we know that Resistors, Inductors and Capacitors form the most important components in the entire field of study. I will try to explain some basic concepts of inductors and Capacitors here.

Inductors

1. Inductor is an element that stores energy in the form of magnetic energy.
2. An inductor does not allow sudden change of current.
3. The property of an inductor by which it opposes sudden change in current is called inductance.
4. The unit of inductance is Henry.
5. An inductor behaves as short circuit when supply is DC source.
6. The current through an inductor lags the voltage across the inductor,by 90 degrees in case of pure inductor.

Capacitors

1. Capacitor is an element that stores energy in the form of electrostatic energy.
2. An capacitor does not allow sudden change in voltage.
3. The property of a capacitor by which it opposes sudden change in voltage is called capacitance.
4. The unit of capacitance is Farad.
5. A capacitor behaves as open circuit when supply is DC source.
6. The current through a  capacitor leads the voltage across the capacitor,by 90 degrees in case of pure capacitor.

Hello,

I would like to show very first how to visualize the subject. For this, we should have total concentration. To avoid obstacle coming in front of us, we will follow the following steps.

Close your eyes, try to identify any Object.,Whatever it may be and ask the following questions yourself.

1. What is that object made from?
2. What are the properties that an object supposed to have to perform functional need?
3. Is that object has this property by birth, or it introduced by some mean? If yes, what are that processes?
4. How one can come to know the properties of any object? Available instruments for that.
5. What might be failure problems faced by that object, and what preventive measures we can do?

This is a reverse engineering way of learning and teaching,

Eg.

1. I imagine object_ Helmet.
2. It should be tough enough if impact occurs on it and at the same time smooth inside to protect the head from injury.
3. All those things not by birth and artificially added by material selection to selecting mfg, the process followed with Heat Treatment.
4. Confirmation properties by Impact Test, Hardness Test, etc.
5. It may corrode, get scratched, and wear tear, so the appropriate coating is necessary for the same.

These all things you will get from nothing from Material Science and Metallurgy subject. All that complicated things we have to step by in this subject.

I hope you will better understand the importance of this subject.

Bar Bending Schedule, commonly referred to as “BBS” is a comprehensive list that describes the location, mark, type, size, length and number, and bending details of each bar or fabric in a Reinforcement Drawing of a Structure. ... In context of Reinforcement bars, it is called bar scheduling.

Introduction

Very frequently, we need to calculate frictional pressure drops in pipelines. Many of us may have domestic pumps in our households. After we estimate the pump flow from expected consumption of water, we need to calculate the pump head for purchasing a suitable pump. The following is an example of calculation of pressure drop when the flow and pipe geomerty is known.

Input Data(assumed)

1. Pipe flow -10 m³/h

2. Fluid-Water at 25⁰C. 

3. Pipe material-commercial galvanised carbon steel (absolute roughness ε=0.15 mm)

4.. Flow geometry as below(total pipe length L=20 m).

h₁=3m

h₂=12m

Calculation

Step-1 Calculation of flow velocity

From pipe dimension table for 25mm NB std thickness pipe

OD (D)=33.4 mm

Thickness (t)=3.38 mm

Hence ID(d)=D-2t=33.4-2x3.38=26.64 mm=0.02664 m

Pipe flow area (A)=(π/4)d²= (π/4)x0.02664²=0.000557 m² 

Pipe flow (Q)=10 m³/h=10/3600=0.00278 m³/s

Hence pipe flow velocity(V)=Q/A=0.00278/0.000557=4.98 m/s

Step-2 Calculation of Darcy's Friction Factor(f)

Kinematic viscosity of water(ν)=8.92x10^-7 m²/s

Reynold's number (Re)=Vd/ν=4.98x0.02664/8.92x10^-7=1.9x10⁵

Re>2000 hence flow is turbulent

For determining f we use Moody's chart s below:

 ^{Relative roughness (ε/d)=0.15/1000/0.02664=0.005631}

^{We noe find f from Re and ε/d as follows}

^{Hence f=0.031}

 ^{Step 3 Calculation Pipe Friction Drop}

 Total pipe length L=20 m

Minor losses

Minor losses are calculated by K factors. Different K factors are available in the internet(refer Crane Technical Paper 410)

a) Inlet loss-K₁=1

b) Foot valve with strainer-pressure drop Δp_f1=0.1 bar(assumed)=1x10⁴ Pa

c) Elbows 90⁰ -3 Nos, K₂=3x30f=3x30x0.031=2.79

d) Gate valve -2 nos, K3=2x8f=2x8x0.031=0.496

e) Exit loss, K4=1

Total head drop

h_f= (fL/D+K₁+K₂+K₃+K₄)V²/2g+ Δp_f1/ρg (Note :ρ=density=1000 kg/m³)

=(0.031x20/0.02664+1+2.79+0.496+1)(4.98²/2x9.81)+1x10⁴/(1000x9.81)

=37.12 mwc

Step 4 Calculation of Pump Head

In addition to frictional head loss we have static head increase

Pump head (H)=(h₁+h₂)+h_f= 3+12+37.12

H=52.12 mwc

We normally take some margin (say 15 %)for future increase in pipe friction drop due to ageing and calculation uncertainties.

So

H=52.12x1,15=60 mwc

Pump details, 10 m³/h flow, 60 mwc head.

      The present-day computer has evolved through several stages. The roots of the evolution are spread evenly in the prehistoric periods when the ancient man started to settle down in dwelling centres. In this period he started cultivation and other productive engagements. He faced the need for counting his products at this stage. In the early stages, he used his fingers for counting purposes. This was the reason for the establishment of a counting system based on the number ten, which is considered to be the most ancient system.

1. ABACUS

         The earliest counting machine, invented by man was a primitive one called ABACUS. It was developed by Chinese nearly 3000 years ago, the Abacus is known as 'Swan Pan' in China. This model is considered to be the best one among other Abacus models used in other countries.

         Abacus consists of a rectangular wooden frame with horizontal rods. These rods carry round beads. These beads are made out of stones, pearls, wooden blocks. Counting is done by shifting the beads from one side of the Abacus to another. One bead on a particular wire has the value of 1; two together have the value of 2. A bead on the on next line has the value of 10, and the bead on the third line would have the value of 100. Therefore, three properly placed beads - two with values of 1 and one with the value of 10 - could signify 12, and the addition of a fourth bead with the value of 100 could signify 112. Thus, the Abacus works on the principle of a place-value notation. The Abacus can be cleared or set to zero by moving all beads away from the crossbar.

1. JOHN NAPER

         John Napier was one of the earliest scientists who tried to invent some devices for calculations. He was A Scottish mathematician. Napier devised a set of rods for use in calculations involving multiplications. These rods were made from bones, and hence this device came to be known as NAPIER BONES. Napier introduced the use of notation to indicate a fractional position.

         The invention of odometer which -is now known as speedometer initiated the development of mechanical adders and multipliers. It was John Napier who developed the method of logarithm in 1617. The tables used in the logarithm represent analogue computing techniques. In logarithm multiplications and divisions can be done by adding and subtracting not the numbers themselves but with the help of related numbers.       

1. BLAISE PASCAL

         The credit for the invention of the first mechanical calculating machine goes to Blaise Pascal. He was a French Mathematician and Physicist, born on June 19, 1623, at Clermont-Ferrand, Auvergne. From the very childhood, Pascal was very much interested in the study of mathematics. When he was only sixteen Pascal published a book on the geometry of the conic sections that for the first time carried the subject well beyond the point at which Apollonius has left it nearly nineteen centuries before.

         In 1642, when Blaise Pascal was only nineteen, he invented the calculating machine called Pascaline, using cogged wheels, could add and subtract. It is considered as the ancestor of the mechanical devices that reached their culmination in the modern cash register.

         Blaise Pascal invented the calculating machine only to assist his father in tax calculations. His father was appointed as the Tax Superintendent of Royen.

         The calculating machine invented by Pascal consisted of gears, wheels and dials. Each wheel had ten segments, which can be compared to the wheel of a milometer. When one wheel completed 0 to 9 around their circumference, with this calculator addition and subtraction could be performed by dialling the series of wheels. He also invented the syringe, the hydraulic press, and Pascal's law of pressure. The basic principle of his calculator is still used today in water meters and modern-day odometers.

1. GOTTFRIED WILHELM VON LEIBNIZ

         Leibniz was a German philosopher and mathematician, born on July 1, 1646, at Leipzig, Saxony. He devised a calculating machine superior to that of Pascal. Leibniz modified the mechanical calculator invented by Pascal and perfected it to a certain context. The modified machine could multiply and divide as well as add and subtract. Leibniz was the first to recognize the importance of the binary system of notation, making the use of 1 and 0 only. This is important in connection with modern computers.

1. JOSEPH-MARIE JACQUARD

         He was a stonemason and later a weaver. He created the Punched Card Loom in 1801. This device was a new type of loom for weaving cloth—punched cards controlled its operation. Needles could pull threads through cards where there were holes and not where there were none. Thus patterns were stored on punched cards. It was adopted by Charles Babbage to control his Analytical Engine.

1. CHARLES BABBAGE

         He was an English mathematician born on December 26, 1791. He conceived of a machine that could be directed to work using punched cards, that could store partial answers to be performed upon them later, and that could print the results. Babbage developed a machine which he called the 'DIFFERENCE ENGINE'. This machine worked on a mathematical technique which repeatedly added differences between numbers to perform various types of calculations. Charles Babbage made only a working model of the difference engine. He did not make a full-scale difference engine because the necessary technology needed for its completion was not available at that time.

         Later on, he was able to develop another device called the 'ANALYTICAL ENGINE'. This was an automatic computing machine designed to make additions at the rate of sixty per minute. It had memory also. Babbage has introduced an input device also which was nothing but a collection of punched cards. He also introduced a control unit whose function would be to control the various operations of the engine. In short, the analytical engine was indeed a marvellous blueprint of a modern computer.

1. GEORGE SCOUTS

         Two Swedish printers, George Scheutz and his son Edward attracted towards the difference engine, and they were successful in making the first difference engine which became very popular among scientists as well as common people. Subsequently, they build several different engines. They got a Gold Medal at the Paris Exhibition in 1855 as the makers of the difference engine.

1. HERMAN HOLLERITH

         He built few difference engines in 1890 for use in the mathematical calculations of the census conducted there. These engines were proved to be highly efficient, and subsequently, several different engines were in use in the different parts of the world.

         The success story of his machine encouraged Hollerith to start the 'Tabulation Machine Company' in 1896. Later in 1911, this company became the 'Computing Tabulating Recording Company' This company is now known as the 'International Business Machines' - IBM Company.

BASIC PRINCIPLES IN SURVEYING

PRINCIPLE OF WORKING FROM WHOLE TO PART

• It is a fundamental rule to always work from the whole to the part. This implies a precise control surveying as the first consideration followed by subsidiary detail surveying.
• This surveying principle involves laying down an overall system of stations whose positions are fixed to a fairly high degree of accuracy as control, and then the survey of details between the control points may be added on the frame by less elaborate methods. 

• Once the overall size has been determined, the smaller areas can be surveyed in the knowledge that they must (and will if care is taken) put into the confines of the main overall frame. 

• Errors which may inevitably arise are then contained within the framework of the control points and can be adjusted to it.

Surveying is based on simple fundamental principles which should be taken into consideration to enable one get good results: 

(a) Working from the whole to the part is achieved by covering the area to be surveyed with a number of spaced out control point called primary control points called primary control points whose pointing have been determined with a high level of precision using sophisticated equipments. Based on these points as theoretic, a number of large triangles are drawn. Secondary control points are then established to fill the gaps with lesser precision than the primary control points. At a more detailed and less precise level, tertiary control points at closer intervals are finally established to fill in the smaller gaps. The main purpose of surveying from the whole to the part is to localize the errors as working the other way round would magnify the errors and introduce distortions in the survey. In partial terms, this  principle involve covering the area to be surveyed with large triangles. These are further divided into smaller triangles and the process continues until the area has been sufficiently covered with small triangles to a level that allows detailed surveys to be made in a local level. Error is in the whole operation as the vertices of the large triangles are fixed using higher precision instruments.

(b) Using measurements from two control parts to fix other points. Given two points whose length and bearings have been accurately determined, a line can be drawn to join them hence surveying has control reference points. The locations of various other points and the lines joining them can be fixed by measurements made from these two points and the lines joining them.

IMPORTANCE OF SCIENTIFIC HONESTY 

• Honesty is essential in booking notes in the field and when plotting and computations in the office. There is nothing to be gained from cooking the survey or altering dimensions so that points will tie-in on the drawing. It is utterly unprofessional to betray such trust at each stage of the survey.
• This applies to the assistants equally as it does to the surveyor in charge. Assistants must also listen carefully to all instructions and carry them out to the later without questions.

CHECK ON MEASUREMENTS

• The second principle is that; all survey work must be checked in such a way that an error will be apparent before the survey is completed.
• Concentration and care are necessary in order to ensure that all necessary measures are taken to the required standard of accuracy and that nothing is omitted. Hence they must be maintained in the field at all times. 

• Surveyor on site should be checking the correctness of his own work and that of others which is based on his information.
• Check should be constantly arranged on all measurements wherever possible. Check measurements should be conducted to supplement errors on field. Pegs can be moved, sight rails altered etc. 

• Survey records and computations such as field notes, level books, field books, setting out record books etc must be kept clean and complete with clear notes and diagrams so that the survey data can be clearly understood by others. Untidy and anonymous figures in the field books should be avoided. 

• Like field work, computations should be carefully planned and carried out in a systemic manner and all field data should be properly prepared before calculations start. Where possible, standardized tables and forms should be used to simplify calculations. If the result of a computation has not been checked, it is considered unreliable and for this reason, frequent checks should be applied to every calculation procedure. 

• As a check, the distances between stations are measured as they are plotted, to see that there is correspondence with the measured horizontal distance. Failure to match indicates an error in plotting or during the survey. 

• If checks are not done on observations, expensive mistake may occur. It is always preferable to take a few more dimensions on site to ensure that the survey will resolve itself at the plotting stage

 ACCURACY AND PRECISION

These terms are used frequently in engineering surveying both by manufacturers when quoting specifications for their equipments and on site by surveyors to describe results obtained from field work.

• Accuracy allows a certain amount of tolerance (either plus or minus) in a measurement, while; 

• Precision demands exact measurement. Since there is no such things as an absolutely exact measurement, a set of observations that are closely grouped together having small deviations from the sample mean will have a small standard error and are said to be precise.

Horizontal Distance Measurement

One of the basic measurements in surveying is the determination of the distance between two points on the earth’s surface for use in fixing position, set out and in scaling. Usually spatial distance is measured. In plane surveying, the distances measured are reduced to their equivalent horizontal distance either by the procedures used to make the measurement or by applying numerical corrections for the slope distance (spatial distance). The method to be employed in measuring distance depends on the required accuracy of the measurement, and this in turn depends on purpose for which the measurement is intended

Pacing: where approximate results are satisfactory, distance can be obtained by pacing (the number of paces can be counted by tally or pedometer registry attached to one leg). Average pace length has to be known by pacing a known distance several times and taking the average. It is used in reconnaissance surveys& in small scale mapping.

Odometer of a vehicle: Based on diameter of tires (no of revolutions X wheel diameter); this method gives a fairly reliable result provided a check is done periodically on a known length. During each measurement a constant tyre pressure has to be maintained.

Tachometry: -Distance can be can be measured indirectly by optical surveying instruments like theodolite. The method is quite rapid and sufficiently accurate for many types of surveying operations.

Taping (chaining): - This method involves direct measurement of distances with a tape or chain. Steel tapes are most commonly used .It is available in lengths varying from 15m to 100m. Formerly on surveys of ordinary precision, lengths of lines were measured with chains.

Electronic Distance Measurement (EDM): - are indirect distance measuring instruments that work using the invariant velocity of light or electromagnetic waves in vacuum. They have high degree of accuracy and are effectively used for long distances for modern surveying operations.