2016

IndiKart India 1:18 PM , , , , , ,
Objective of the Lecture:
  • Machine
  • Mechanism
  • Theory Of Machine 
  • Kinematics
  • Dynamics

Machine: Machine is a kind of device which used to transfer and transform the motion and force from source to the load, where source can be defined as Input while the load can be state as Output.

Machine can also be define as a device from which the available energy can be converted into the desired form of useful work.

Mechanism: Mechanism can be defined as the combination of the rigid or resistant bodies, formed and connected so that the motion of one imparts the required motion to the other and the bodies are able to withstand the various kind of forces impressed upon them.

Theory Of Machine: Theory Of Machine is a branch of engineering which deals with the study of relative motion in between the various part of a machine and the various forces which act on the machines. 

Theory of machine is mainly classified in two categories:

1. Kinematics

2. Dynamics

Kinematics: The subject which deals with only the geometric aspects (constraints) of motion of the various machine elements without any consideration of forces causing such motion, is termed as Kinematics.

Dynamics: The subject which deals with the geometric aspects of motion of various machine elements while considering the forces acting, causing such motion, is termed as Dynamics.

Dynamics further can be sub-divided in the following parts;

Statics:  The branch of Dynamics which deals with the forces acting on the various machine elements, at rest, is termed as Statics. In this, the mass of the machine elements is assumed to be zero.

Kinetics: The branch of Dynamics which deals with the inertia forces, occurring due to the combined effect of mass and the motion of the machine elements, is termed as Kinetics.

LECTURE RELATED QUESTIONS:

1. What is a machine?

2. What is 'Theory Of Machine'?

3. Define Kinematics.

4. Define Dynamics.

5. What are the sub-categories of Dynamics? Briefly describe each of them.
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IndiKart India 5:49 PM , , , , , , , , , ,
Objectives of the Lecture:
  • Types of Rocks
  • Sedimentary Rocks
  • Metamorphic Rocks
  • Igneous Rocks
Natural occurring rocks are too dense, massive and strong, as because of such reasons, from last many decades these are being used  in construction of structures. Rocks, basically are of three types:

1. Sedimentary Rocks: Sedimentary Rocks are those rocks which are formed by the accumulation of sediments within the glaciers, rivers, oceans etc. These sediments were bonded beneath the soil from last so many of years, resulting formation of sedimentary rock bed.

Example of the Sedimentary rock includes: Chalk, Limestone, Sandstone etc.


2. Metamorphic Rocks: Metamorphic rocks are those rocks formed by the transformation of the pre-existing rock, subjected to very high heat and pressure, resulting in the physical as well as chemical change in the nature of rock. 

Example of the Metamorphic rock includes: Slate, Marble etc.
3. Igneous Rocks: Igneous rock got their name from the Latin word "Ignis" which stands for fire. Igneous rocks are those rocks formed by the solidification of the magma or lava. These are generally of two types: Intrusive and Extrusive.

Intrusive Igneous Rocks are formed from the trapped magma that cools down and solidified within the crust of the planet. Intrusive rock cools very slowly, as a result, these rocks are coarse-grained.

Example of the Intrusive Igneous Rocks includes: Granite, Diorite etc.

Extrusive Igneous Rocks are formed from the cooling and solidification of the molten lava, which used to form above the earth's crust. Extrusive rock cools much faster as compared to intrusive and as a result, these rocks are fine-grained.

Example of the Extrusive Igneous Rocks includes: Basalt, Pumice etc.


LECTURE RELATED QUESTIONS:

 1. Classify the types of rocks and briefly describe each of them.

2. What is Metamorphic Rock? Give few example of metamorphic rock.

3. What is Sedimentary Rock? Give few example of sedimentary rock.

4. What is Igneous Rock? Give few example of igneous rock.

5. Classify the types of Igneous rock and briefly describe each of them with example.
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IndiKart India 8:55 PM , , , ,
Objectives of this Lecture:

  • Characteristics of a Good Building Stone

CHARACTERISTICS OF A GOOD BUILDING STONE
  • Appearance: The Building Stones being used in the construction work should be uniform in color as well as should not have spots of color within the stone. Lighter color of stones are more preferable than the darker stones as latter are less durable. It also should have pleasant color and free from patches too.
  • Strength: Building Stones must have good compression strength. Building stones should be able to withstand a minimum crushing strength of 1000 kg/cm2 .
  • Durability: It should be able to withstand and resist the action of the atmosphere such as rain, wind, temperature etc
  • Texture: It is preferred to have building stones with fine crystalline compact structure as those are more stronger.
  • Dressing: It should be easy to cut the stone and to dress it into different shape for carving and structural works.
  • Seasoning: Every freshly quarried stones contain a bit amount of moisture content, termed as quarry sap. It is essential that after quarrying and dressing of the stone, it should be left for minimum 6 to 12 months before using such stones for construction.
  • Toughness: Building stones should be able to resist and withstand the load and stress developed due to the vibration of moving machinery.
  • Porosity and Absorption: A good building stone should not be porous and not absorb more than 5% of water when immersed.
  • Heaviness: Building stones used in the construction of dams, barrages should be of high varieties. A stone should have specific gravity in ranges from 2.4 to 2.8. 
  • Resistance to fire: A Building stone should be free from minerals such as calcium carbonate and oxides of iron and also, the minerals present in stones should not have different co-efficient of thermal expansion. Building Stones should also be able to resist high temperature.

LECTURE RELATED QUESTIONS:

1. What are the various characteristics of a good Building Stone?

2. Write down the 10 features of a good building stone.
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IndiKart India 8:05 PM , , , ,
Objectives of the Lecture:

  • Building Stone
  • Building Stone - Uses and Applications

Building Stone

Stone is a natural material obtained by the erosion of the rocks. Stones being used for the purpose of construction of the building structures are being termed as "Building Stones". Building stone not just only increase your's home beauty as well as provide good strength to your building structure. Our ancestors, long year ago, started using these stones as a building material as well as they also uses some of the stones to ignite the fire and to develop the sharp tools.

Let us move up towards the uses and applications of these Building Stones.


Building Stone - Uses and Applications
  • It's being used in the construction of walls, masonry works, foundations,lintels, slabs, cornices etc.
  • Stone is also being used in the construction of roads and pavements.
  • Stones are also used as ballast in railway track gauges.
  • It is also used as a coarse aggregate in concrete.
  • It is also being used in making urinals, bathing tubs, and other products.
  • Stone is also being used as a roofing as well as flooring material in a building.
  • These stones are also used in the manufacture of the cement.
  • Stones are also being used in the making of the sculpture arts.
  • Stones are used in the water treatment process.
  • Stones are used in building wells, construction of bridges, dams etc.
  • Stones are used as an insulators in electrical appliances.
  • Stones are also used in making the sharp tools.

LECTURE RELATED QUESTIONS:

1. Define Building Stone.

2. State the various uses and applications of building stones.

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IndiKart India 4:05 PM ,
Objective of the lecture :

  • Heat Engine
  • Refrigerator
  • Heat Pump


 Heat Engine :

A heat engine is a device that does a certain amount of net positive work by the extraction of heat from a high temperature body and releasing it to low temperature body. In this, the required output is the net positive work done by the heat extracted from the hot body. Example of heat engine includes : Steam power plant etc.

Refrigerator : 

Refrigerator is a device which is used to reduce and maintain the temperature of the cold chamber below the atmospheric temperature by extracting the heat from the cold chamber and releasing it continuously in the environment by consuming certain amount of external work. In this, the required output is the heat extracted from the cold chamber. Examples includes : Domestic Refrigerators etc.

Heat Pump : 

Heat Pump is a device which used to transfer the heat of the cold body by extracting the heat from the cold body and releasing it continuously in the hot chamber by consuming certain amount of external work. A heat pump is much similar to refrigerator, however, here the required output is the heat rejected to the high temperature body.


LECTURE RELATED QUESTIONS :

1. What is a Heat Engine?

2. Define "Refrigerator".
 
3. What is Heat Pump?

4. Write down the difference in between Heat Engine, Refrigerator and Heat Pump and explain them.
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IndiKart India 8:16 PM ,
Objective of the lecture :
  • Standard Rating Of Refrigerating Machine
  • Tonne of refrigeration


Standard Rating Of Refrigerating Machine :

The "standard rating of refrigeration" is obtained by refrigerating effect or amount of heat extracted in a given time from a refrigerating body. The practical unit of refrigeration is generally represented in terms of “tonne of refrigeration” (briefly expressed as TR). 

One Tonne Of Refrigeration :

A “tonne of refrigeration” is a common term used to indicate the capacity of the refrigerating unit. A “tonne of refrigeration” is defined as the amount of refrigeration effect produced by uniform melting of one tonne of ice from and, at OoC in 24 hours.

Since, Latent Heat of Ice = 335 kJ/kg.

Therefore, tonne of refrigeration in 24 hour = 335 x 1000 kJ in 24 hr.

So, tonne of refrigeration per hr. = [ { (335 kJ/kg) x (1000 kg) } / ( 24 hr. ) ]
                                                              = 13958.33 kJ/hr.

So, tonne of refrigeration per min. = [ { (335 kJ/kg) x (1000 kg) } / ( 24 hr. x 60 min. ) ]
                                                              = 232.6 kJ/min.

And, tonne of refrigeration per sec. = [ { (335 kJ/kg) x (1000 kg) } / ( 24 hr. x 60 min.  x 60 sec.) ]
                                                                  = 3.5 kJ/sec.

When one tonne of ice requiring 335 kJ/kg got melted in 24 hour period, it is termed as "heat transfer rate" of 1 tonne of refrigeration.


Also, tonne of refrigeration is also expressed in Btu/hr.

Then, Latent Heat of Ice = 144 Btu/lb.

Therefore, tonne of refrigeration in 24 hour = 144 x 2000 kJ in 24 hr.

So, tonne of refrigeration per hr. = { (144kJ/kg) x (2000lb) } / ( 24hr. ) ]

                                                = 12000 Btu/hr.


LECTURE RELATED QUESTIONS : 

1. What do you know about "Standard Rating Of Refrigerating Machine"?

2. What do you understand by "tonne of refrigeration"? 

3. What do you mean by "Heat transfer rate" in relation to tonne of refrigeration?

4. Write down the unit values of "tonne of refrigeration" expressed in Btu/hr. , Btu/min. and kJ/sec. respectively.
Read more »

IndiKart India 7:51 AM ,
Objective of the lecture :
  • Human Comfort

HUMAN COMFORT 

Thermal comfort, also termed as neutral comfort, may be defined as “that condition of mind which expresses satisfaction with the thermal environment”.

As we all know that, the chemical energy of our food get converted into heat and work which is then utilised for the proper functioning of our body organs including heart, brain, lungs, liver and other parts of body organ and then ultimately, the energy is rejected into the environment in the form of the waste and urea.

Such process of conversion of conversion of chemical energy present in the food to heat and work is termed as “metabolism”. The rate at which the process of conversion of the chemical energy presented in the food into heat and work happens is termed as “metabolic rate”.  The knowledge of metabolic rate and other factors including humidity, air temperature and air velocity etc. are very necessary so as to know the  cooling load of the air conditioned building. To define thermal efficiency of a human being, one can termed it as “the ratio of the useful work output to the energy input”. The thermal efficiency of a human being can vary from 0% to as high as 15-20% for a short duration of time.
For the efficient working condition of human body, the internal organs require the temperature close to 35o C and this is achieve by rejecting appropriate amount of heat in the surroundings.

Core temperature = 36.8o C
Skin Temperature = 33.7o C

If the temperature of the human body rises above this temperature, then human body tries to achieve this temperature range which is achieved by perspiration process of the body. Human beings do not feel comfortable if the body require some extra effort to reject this energy to the environment, which results in major loss in efficiency.  


LECTURE RELATED QUESTIONS : 

1. Define the term "Human Comfort".

2. Define "Metabolism".

3. Define "Metabolic Rate".

4. Write down the factors affecting the human comfort.

5. Define "thermal efficiency" of a human being.

6. What is the core and skin temperature of a human body?
Read more »

IndiKart India 12:20 PM ,

Objective of the lecture:
  • Meaning of Refrigeration
  • Applications of Refrigeration

 Meaning Of Refrigeration:

Refrigeration may be defined as the process of extraction of the heat from the cold bodies and releasing it to the higher temperature bodies so as to achieve and maintain the temperature below that the surrounding. 

Applications of Refrigeration:

The application of refrigeration are too wide in domestic as well as in industries. Some of them are mentioned below:

1. Manufacturing of ice
2. Medical applications
3. Preservation of perishable food product
4. Storage and Distribution of Beverages
5. Ice skating rinks
6. Meat and poultry products
7. Preservation of Dairy Products
8. Application in Chemical Industries
9. Application in Printing Industries
10. Desalination of water
11. Cold treatment of metals
12. Removal of heat of extraction
13. Dehumidification of air
14. Condensation of gases

LECTURE RELATED QUESTIONS:

1. Explain the term 'Refrigeration'.

2.Write down the domestic and industrial applications of Refrigeration.
Read more »
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