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December 10, 2019

Question 1. What Is Safety ?
Answer :
  • It is a condition which gives you freedom from hazard, risk, accident which may cause injury, damage and loss to material or property damage and even death.
  • Safety is defined as freedom from those condition that can cause injury to persons including death or damage to property or environment.
Question 2. What Is Accident ?
Answer :
It is an unexpected or unplanned event which may or may not result in injury or damage or property loss or death.
Question 3. What Is Injury ?
Answer :
It is defined as a harmful condition sustained by the body as a result of an accident.
Question 4. What Is Hazard ?
Answer :
Inherent property of a substance or an occurrence which has potential to cause loss or damage property, person or environment.
Question 5. What Is Risk ?
Answer :
In probability of the realization of potential for loss or damage or injury.
Question 6. What Is Incident?
Answer :
It is an event which represents deviation from the intended sequence of designed steps.
Question 7. What Is Safety Policy?
Answer :
Any company has a social and legal obligation to provide a safe and health working environment to all his improvement to all his employees.
Question 8. What Is Safety Audit?
Answer :
The safety audit is the process that identifies un-safe conditions and unsafe acts the plant and recommended safety improvement.Walk through It evaluates the unsafe condition notice able to naked eye during work through the plant. ( Stores, civil work, erection work) Inter mediate-more details study and review of plant design and plant operation. Comprehensive –It evaluates the safety factors in the plant on the base engineering, analysis, testing, measurement.
Question 9. What Is Safety Tag?
Answer :
Safety tag can be defined a surface made of card board or paper board on which English local languages letters written for warning safety instructions to employees.
Question 10. What Is Safety Programme?
Answer :
Safety programme can be defined as five methods by which accident can be prevent easily they are engineering, education, enforcement, enthusiasm and example safety programmes are plain spoken and carry out certain legal steps.
Question 11. What Is Attitude?
Answer :
Attitude may be described as continuous behavior . if man’s behavior is good, then his action will be either correct or safe.
Question 12. What Is Emergency Planning?
Answer :
Emergency planning can defined as a control measurer. It can control the accidents safe guard people and provide information to media.
Question 13. What Is Work Permit System?
Answer :
Work permit system is a “ written documents” for permission to undertake a job by area in charge or it is written document issued by the area in charge to the performer to under take the specific job.
Question 14. What Is Work At Height?
Answer :
Any work above 2 meters from ground is caused work at height.
Question 15. What Is Confined Space?
Answer :
An area which is small and enclosed or an area where one entry and exits or where a man cannot work comfortable in any location is caused confined space.
Question 16. What Is Excavation?
Answer :
Marking a hole or tunnel by digging the ground by man or machine is called excavation.
Question 17. What Is Scaffolding?
Answer :
It is a temporary platform constructed for supporting both men and materials and working safety at a construction site.

Question 18. What Is Welding?
Answer :
The process of joining of metals either by electrical or by gas is called welding.

Question 19. What Is Gas Cutting ?
Answer :
The process of joining of cutting metals by using oxygen and combustible gas is called gas cutting.
Question 20. What Is Sand Blasting?
Answer :
The process of removing rust dust, dirt, scales and old prints from the old surface using compressed air is called sand blasting.
Question 21. What Is Painting?
Answer :
The process after sand blasting is called painting .
Question 22. What Is Lel?
Answer :
The minimum concentration of vapour, gasses and dust in air below which propagation of flame does not occur on contact with a source of ignition is called LEL.
Question 23. What Is Uel?
Answer :
The maximum proporation of vapour, gasses and dust in air above which proposal the flame does not occur on contact with a source of ignition is called UEL.
Question 24. What Is Manual Handing?
Answer :
The process of lifting, carrying and stacking materials by men is called manual handing.
Question 25. What Is House Keeping?
Answer :
House keeping means not only cleanness but also orderly arrangement of operations, tools, equipments storage facilities and suppliers.
Question 26. What Is Personal Protective Equipment?
Answer :
It is an equipments used to project the person from hazards such dust, dirt, fumes and sparks etc. It is the barrier between hazard and person.
Question 27. What Is Grinding?
Answer :
Grinder is a portable machine with a wheel guard in position to reduced the danger.
Question 28. What Is Crane?
Answer :
A tall machine used for moving heavy objects by suspending them from a projecting arm with hook.
Question 29. What Are The Duties Of A Safety Officer?
Answer :
  • Prepare tool box talk
  • Prepare monthly statistics
  • Prepare the checklist
  • Accident reports
  • Management meetings
  • Arrange the safety classes/training
  • Arrange monthly safety bulletin
  • Inspection of fire extinguisher
  • Arrange first aid training classes
  • Arrange safety competitions like quiz, slogan, poster competitions exhibition etc.
Question 30. What Are The Duties Of A Supervisor?
Answer :
  • He has to instruct this workers about the work methods and procedures.
  • He has to maintain discipline among the workers
  • He has to supply necessary materials
  • He has to control quality and cost of the job
  • He has to guide has workers in doing a job in the correct and safe way
  • He has to supply suitable personal protective equipment to his workers
  • He should conduct periodical safety meetings.
  • He should conduct safety inspection of his working area
  • He should know about the fire fight equipments
  • He should know investigate the accident and find out the cause of accident
Question 31. What Are The Pre Cautions For Welding?
Answer :
  • Remove all combustion material from the place of welding
  • Clear the work area and cover wooden floor with fire proof mats. ( Welding mechanic should be kept with in the visibility of the welders.
  • Erect fire resistance screen around the work
  • All welding cables should be fully insulted
  • All welding mics shall be double earthed
  • Welding area should be dry and free from water
  • Keep the fire extinguisher / sand really
Question 32. What Is The Precaution For Gas Cutting?
Answer :
  • Keep fire extinguisher nearby
  • Keep fire watch near by
  • Remove all combustible from work area
  • Use all necessary PPE
  • Never put welding gas cylinder in side a confined space
  • Hoses shall not be laid in path ways
  • Gas cutting torch should have flash back arrestors
  • Gas test to be done to check for presence of flammable gas in site.
  • Good house keeping and ventilation necessary in working area.
  • Hose connections should be made properly
Question 33. What Are The Hazards In Welding?
Answer :
  • Eye injury
  • Burn injury Arc realization
  • Electrical shock Light arc radiation
  • Heat, light and radiation effect Heat fume
  • Poisonous gases Chipped price of weld metal
  • Fire
  • Explosion Scattering
  • Noise Sparking
  • Sparking
  • Flying sand
Question 34. What Precautions Are Need To Avoid Accident In Manhandling?
Answer :
  • Stand at safe distance from the load
  • Sharp edge and burns are removed before lifting a material.
  • PPE such as safety gloves and safety shoes are to be used.
  • If the weight is too heavy for one person to lift, then he has to seek the assistance.
  • The pathway is not blocked by obstacles while carrying the load.
  • The different actions, movements and forces necessary while carrying the load.
  • Modify the task by using hooks and crow bars.
  • Mechanical equipments like cranes shall be used.
  • Modify the objects
  • Change the way things are used.
Question 35. General Safety Precautions In Construction?
Answer :
  • Adequate first aid equipment should be kept ready
  • Adequate fire fighting equipment should be available
  • All general electrical rules should be followed
  • suitable lighting arrangements should be necessary at night work
  • Work men at height should be wear safety belts
  • Work men handling cement should be provided with goggles, rubber gloves and rubber boots by nose mask.
  • The moving parts of grinding machines used construction site should be covered with guards
  • The moving parts of grinding machines used construction site should be covered with guards
  • Excavated material should not kept near the excavated
  • Very short duration of work red flags must be hoisted and more duration red banners must be stretched
  • Defective tools should not be used
  • The worker should not carry tools in his hands when climbing a ladder
  • Excavation should be guarded by suitable fencing
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December 05, 2019
Have you ever wondered ? Why capacity of domestic refrigerator and Air Conditioner (AC) is different though both are refrigeration system? What is the basic difference between them with respect to the cooling capacity?


The capacity of domestic refrigerator is normally rated in 'Litre'. Litre actually a unit of volume and it is also applicable to the domestic refrigerator while dealing with space to be cooled. Thus, litre capacity actually indicates the volume or space to be cooled by domestic refrigerator.


On the other hand, capacity of Air Conditioner (AC) is given by term 'Ton'. Now, this term, 
What is one Ton refrigeration?
'Ton' is actually a name given to amount of heat to be extracted from 1 short ton (907.18474 kg) of water at 0 degree C to convert it to ice at the same temperature in 24 hours. (Note: 1 large ton = 1016.0469 kg, 1 metric ton = Tonne = 1000 kg)
In other words, refrigeration rate required to freeze 1 ton of water to ice in 24 hours at 0 degree C.
Thus, 1 Ton of refrigeration = 1 TR = (latent heat of ice)x(amount of water)/time
= 334 x 907.18474 /(24 x 3600)
= 3.50 kW
So, both refrigeration system has different capacity term namely 'Litre' (Space to be cooled) & 'Ton' (3.5 kW) energy to be removed for cooling)



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December 04, 2019


What is a fluid?

Matter around us exists in three phases (excluding plasma)
1.       Solid
2.       Liquid
3.       Gas
From the above three phases liquid and gas are combinedly known as fluids.
The main difference between fluids and solid lies in their ability to resist shear stresses.
When a constant shear force is applied, a solid eventually stops deforming, whereas a fluid never stops deforming and approaches a constant rate of strain
(ref. fluid mechanics by Cengel & Cimbala)

Types of fluids

On the basis of shear and velocity gradient relationship, fluids can broadly be classified into following five types.
Types of fluids
Types of fluids

1.       Ideal fluid
Ideal fluid is incompressible and has no viscosity. It is an imaginary fluid and does not exists in reality.
2.       Real fluid
Real fluid possesses viscosity. In practice all fluids are real.
3.       Newtonian fluid
A real fluid which obeys Newton’s law of viscosity is known as Newtonian fluid.
Note: According to Newton’s law of viscosity shear stress is directly proportional to strain rate.
4.       Non-Newtonian fluids
A real fluid which does not obeys Newton’s law of viscosity is known as Non-Newtonian fluid.
5.       Ideal plastic fluid
A fluid, in which shear stress is more than the yield value and shear stress to proportional to the rate of shear strain, is known as real plastic fluid.

Properties of fluids

There are some basis properties associated with fluids which help us to understand them in a better way.
1.       Viscosity
It is the ratio of applied shear stress to the obtained shear strain rate in fluids. Viscosity offers resistance to the movement of fluid layers.
2.       Pressure
It is the term used in fluids which is analogues to the term stress used in solids. Both are the ratio of applied force and area of surface (on which the force is applied)
3.       Specific gravity
Specific gravity of fluids is defined as the ratio of density of a particular fluid to the density of standard fluid (generally water).

Examples of fluids

●        Water
●        Air
●        Blood
●        Mercury
●        Honey
●        Gasoline
●        Any other gas or liquid


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December 01, 2019
Car manufacturers are constantly playing with all of the following variables to make an engine more powerful and/or more fuel efficient.Here are the 8 ways to Produce more Power in Engine

1. Increase displacement - More displacement means more power because you can burn more gas during each revolution of the engine. You can increase displacement by making the cylinders bigger or by adding more cylinders. Twelve cylinders seems to be the practical limit.
2. Increase the compression ratio - Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however, the more likely it is to spontaneously burst into flame (before the spark plug ignites it). Higher-octane gasolines prevent this sort of early combustion. That is why high-performance cars generally need high-octane gasoline -- their engines are using higher compression ratios to get more power.
3.Stuff more into each cylinder - If you can cram more air (and therefore fuel) into a cylinder of a given size, you can get more power from the cylinder (in the same way that you would by increasing the size of the cylinder). Turbochargers and superchargers pressurize the incoming air to effectively cram more air into a cylinder. SeeHow Turbochargers Work for details.
4. Cool the incoming air - Compressing air raises its temperature. However, you would like to have the coolest air possible in the cylinder because the hotter the air is, the less it will expand when combustion takes place. Therefore, many turbocharged and supercharged cars have an intercooler. An intercooler is a special radiator through which the compressed air passes to cool it off before it enters the cylinder. See How Car Cooling Systems Work for details.
5. Let air come in more easily - As a piston moves down in the intake stroke, air resistance can rob power from the engine. Air resistance can be lessened dramatically by putting two intake valves in each cylinder. Some newer cars are also using polished intake manifolds to eliminate air resistance there. Bigger air filters can also improve air flow.
6. Let exhaust exit more easily - If air resistance makes it hard for exhaust to exit a cylinder, it robs the engine of power. Air resistance can be lessened by adding a second exhaust valve to each cylinder (a car with two intake and two exhaust valves has four valves per cylinder, which improves performance -- when you hear a car ad tell you the car has four cylinders and 16 valves, what the ad is saying is that the engine has four valves per cylinder). If the exhaust pipe is too small or the muffler has a lot of air resistance, this can cause back-pressure, which has the same effect. High-performance exhaust systems use headers, big tail pipes and free-flowing mufflers to eliminate back-pressure in the exhaust system. When you hear that a car has "dual exhaust," the goal is to improve the flow of exhaust by having two exhaust pipes instead of one.
7. Make everything lighter - Lightweight parts help the engine perform better. Each time a piston changes direction, it uses up energy to stop the travel in one direction and start it in another. The lighter the piston, the less energy it takes. 
8. Inject the fuel - Fuel injection allows very precise metering of fuel to each cylinder. This improves performance and fuel economy.


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December 01, 2019

What is Power Plant?

A power plant or a power generating station, is basically an industrial location that is utilized for the generation and distribution of electric power in mass scale, usually in the order of several 1000 Watts. These are generally located at the sub-urban regions or several kilometers away from the cities or the load centers, because of its requisites like huge land and water demand, along with several operating constraints like the waste disposal etc.

For this reason, a power generating station has to not only take care of efficient generation but also the fact that the power is transmitted efficiently over the entire distance and that’s why, the transformer switch yard to regulate transmission voltage also becomes an integral part of the power plant.
At the center of it, however, nearly all power generating stations has an AC generator or an alternator, which is basically a rotating machine that is equipped to convert energy from the mechanical domain (rotating turbine) into electrical domain by creating relative motion between a magnetic field and the conductors.
power plant

The energy source harnessed to turn the generator shaft varies widely, and is chiefly dependent on the type of fuel used.

Types of Power Station

A power plant can be of several types depending mainly on the type of fuel used. Since for the purpose of bulk power generation, only thermal, nuclear and hydro power comes handy, therefore a power generating station can be broadly classified in the 3 above mentioned types. Let us have a look in these types of power stations in details.

Thermal Power Station

A thermal power station or a coal fired thermal power plant is by far, the most conventional method of generating electric power with reasonably high efficiency. It uses coal as the primary fuel to boil the water available to superheated steam for driving the steam turbine. The steam turbine is then mechanically coupled to an alternator rotor, the rotation of which results in the generation of electric power. Generally in India, bituminous coal or brown coal are used as fuel of boiler which has volatile content ranging from 8 to 33% and ash content 5 to 16 %. To enhance the thermal efficiency of the plant, the coal is used in the boiler in its pulverized form.
In coal fired thermal power plant, steam is obtained in very high pressure inside the steam boiler by burning the pulverized coal. This steam is then super heated in the super heater to extreme high temperature. This super heated steam is then allowed to enter into the turbine, as the turbine blades are rotated by the pressure of the steam.

The turbine is mechanically coupled with alternator in a way that its rotor will rotate with the rotation of turbine blades. After entering into the turbine, the steam pressure suddenly falls leading to corresponding increase in the steam volume. After having imparted energy into the turbine rotors, the steam is made to pass out of the turbine blades into the steam condenser of turbine. In the condenser, cold water at ambient temperature is circulated with the help of pump which leads to the condensation of the low pressure wet steam.
Then this condensed water is further supplied to low pressure water heater where the low pressure steam increases the temperature of this feed water, it is again heated in high pressure. This outlines the basic working methodology of a thermal power plant.

Advantages of Thermal Power Plants

●     Fuel used i.e coal is quite cheaper.
●     Initial cost is less as compared to other generating stations.
●     It requires less space as compared to hydro-electric power stations.

Disadvantages of Thermal Power Plants

●     It pollutes atmosphere due to production of smoke and fumes.
●     Running cost of the power plant is more than hydro electric plant.

Nuclear Power Station

The nuclear power generating stations are similar to the thermal stations in more ways than one. However, the exception here is that, radioactive elements like uranium and thorium are used as the primary fuel in place of coal. Also in a Nuclear station the furnace and the boiler are replaced by the nuclear reactor and the heat exchanger tubes.

For the process of nuclear power generation, the radioactive fuels are made to undergo fission reaction within the nuclear reactors. The fission reaction, propagates like a controlled chain reaction and is accompanied by unprecedented amount of energy produced, which is manifested in the form of heat. This heat is then transferred to the water present in the heat exchanger tubes. As a result, super heated steam at very high temperature is produced. Once the process of steam formation is accomplished, the remaining process is exactly similar to a thermal power plant, as this steam will further drive the turbine blades to generate electricity.

Hydro-Electric Power Station

In Hydro-electric plants the energy of the falling water is utilized to drive the turbine which in turn runs the generator to produce electricity. Rain falling upon the earth’s surface has potential energy relative to the oceans towards which it flows. This energy is converted to shaft work where the water falls through an appreciable vertical distance. The hydraulic power is therefore a naturally available renewable energy given by the eqn:

P = gρ QH

Where, g = acceleration due to gravity = 9.81 m/sec 2

ρ = density of water = 1000 kg/m3

H = height of fall of water.

This power is utilized for rotating the alternator shaft, to convert it to equivalent electrical energy.

An important point to be noted is that, the hydro-electric plants are of much lower capacity compared to their thermal or nuclear counterpart. For this reason hydro plants are generally used in scheduling with thermal stations, to serve the load during peak hours. They in a way assist the thermal or the nuclear plant to deliver power efficiently during periods of peak hours.

Advantages of Hydro Electric Power Station

●     It requires no fuel, water is used for generation of electrical energy.
●     It is neat and clean energy generation.
●     Construction is simple, less maintenance is required.
●     It helps in irrigation and flood control also.

Disadvantages Hydro Electric Power Station

●     It involves high capital cost due to dam construction.
●     Availability of water depends upon weather conditions.
●     It requires high transmission cost as the plant is located in hilly areas.

Types of Power Generation

As mentioned above, depending on the type of fuel used, the power generating stations as well as the types of power generation are classified. Therefore the 3 major classifications for power production in reasonably large scale are :-
1.   Thermal power generation.
2.   Nuclear power generation.
3.   Hydro-electric power generation.
Apart from these major types of power generations, we can resort to small scale generation techniques as well, to serve the discrete demands. These are often referred to as the alternative methods or non conventional energy of power generation and can be classified as :-
1.   Solar power generation. (making use of the available solar energy)
2.   Geo-thermal power generation. (Energy available in the Earth’s crust)
3.   Tidal power generation.
4.   Wind power generation (energy available from the wind turbines)

These alternative sources of generation has been given due importance in the last few decades owing to the depleting amount of the natural fuels available to us. In the centuries to come, a stage might be reached when several countries across the globe would run out of their entire reserve for fossil fuels. The only way forward would then lie in the mercy of these alternative sources of energy which might play an instrumental role in shaping the energy supplies of the future. For this reason these might rightfully be referred as the energy of the future.
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