Type of milling cutter

Different types of milling cutters are used in milling operation performed on a milling machine. so let we know first what is milling cutters?

The milling cutter is revolving tools having one or many cutting edges of identical form equally spaced on the circumference of the cutter. The cutting elements are called teeth which intermittently engages the work piece and remove material by relative movement of the work piece and cutter. 

Types of milling cutters :

1. According to constructional features of the cutter :

• Solid cutter
• Tipped solid cutter
• Inserted teeth cutter

2. According to the relief characteristics of the cutter teeth :

• Profile relieved cutter
• Form relieved cutter

3. According to the methods of mounting the cutter :

• Arbor type cutter
• Shank type cutter
• Facing type cutter

4. According to the direction of rotation of the cutter :

• Right-hand rotational cutter
• Left-hand rotational cutter

5. According to the direction of a helix of the cutter teeth :

• Parallel or straight teeth cutter
• Right-hand helical cutter
• Left-hand helical cutter
• Alternate helical teeth cutter

6. According to the purpose or use of cutter :

• Standard milling cutter
• Special milling cutter 

There are many other different types of standard milling cutters. They are classified below : 

1. Plain milling cutter 

• Light duty plain milling cutter
• Heavy-duty plain milling cutter
• Helical plain milling cutter

2. Side milling cutter 

• Plain side milling cutter
• Staggered teeth side milling cutter
• Half side milling cutter
• Interlocking side milling cutter

3. Metal slitting saw 

• Plain metal slitting saw
• Staggered teeth metal slitting saw

4. Angle milling cutter

• Single angle milling cutter
• Double angle milling cutter

5. End mill

• Taper shank end mill
• Straight shank end mill
• Shell end mill

6. T-slot milling cutter

7. Woodruff key slot milling cutter

8. Fly cutter

9. Formed cutter

• Convex milling cutter
• Concave milling cutter
• Corner rounding milling cutter
• Gear cutter
• Thread milling cutter

10. Tap and reamer cutter

Read related posts:

1. Milling machine introduction
2. Difference between turning and milling
3. Working principle of milling machine
4. Milling machine safety precautions
5. Milling machine parts
6. Lubrication used in milling machine
7. Uses of milling machine
8. What is a milling machine?
9. Milling machine uses
10. Milling machine operation

The size of drilling machine

Size of a drilling machine :

The drilling machine size varies with the different types of the machine being considered.

A portable drilling machine is specified by the maximum diameter of the drill that it can hold.

The sensitive and upright drilling machines are specified by the diameter of the largest piece that can be centred under the spindle. This is a case of a 600 mm size upright drilling machine, the spindle placed at a distance is slightly greater than 300 mm from the front face of the column.

The size of the radial drilling machine is specified by the diameter of the column and length of the arm. Other particulars such as maximum drilling radius, minimum drilling radius, spindle speeds and feeds etc. 

To specify a drilling machine fully further particulars such as the maximum size of drill that the machine can operate, table diameter, the maximum spindle travel, numbers of spindle speeds and feeds available.

The size of a lathe

Size of lathe machine expressed in following ways that illustrated below :

• The height of the centres measured from the lathe bed.
• The swing diameter over the bed. It is the largest diameter of work that will revolve without touching the bed and is twice the height of the centre measured from the bed of the lathe.
• The length between centres. This is the maximum length of work that can be mounted between the lathe centres.
• The swing diameter over the carriage. This is the largest diameter of work that will revolve over the lathe saddle and is always less than the swing diameter over the bed.
• The maximum bar diameter. This is the maximum diameter of bar stock that will pass through hole of the head stock spindle.
• The length of the bed. This is the approximate floor shape occupied by the lathe.

Ion beam machining

Ion beam machining is generally a surface finishing process in which the material removal takes place by sputtering of ions.
It is also called the etching process. This is a different process from electric discharge, electron beam, laser beam and plasma arc machining. 

Working Principle :

This process is very simple. It consists of bombarding the work with accelerated ions which collide with the surface atoms of the work. Each bombarding ions, as a result of collisions, dislodges surface layer.
It consists of an electron gun discharging free electrons into a chamber filled with argon gas. The gas is ionized by electrons. The top of the chamber is known as ion-beam generating apparatus. At the other end, the workpiece is fixed to a table which can be oscillated and rotated so that different points on the work surface can be subjected to an ion beam.

Accuracy :

• Etching rates vary up to 2000 Å per min.
• Accuracy of the etching process is considerably high mainly due to the small amount of material removal.
• Tolerances in the vicinity of + 50  Å  to - 50  Å  are possible.

Applications of IBM :

• It is applied mostly in micro-machining of electronic components.
• Typical materials that can be etched included glass, alumina, quartz, crystal, silica, agates, porcelains, numerous metals, cermets and oxides.
• It is also be used to deposit materials such as platinum, tungsten and silicon oxide insulators on another material substrate.

Advantages of IBM :

• IBM is almost universal.
• No chemical reagents or etching are required.
• Etching rates are easily controlled.
• There is no undercutting as with another chemical etching process.

Disadvantages of IBM :

• IBM is relatively expensive.
• Etching rates are slow.
• No heat is generated so there is little possibility of some thermal or radiation damage.

Difference between nuclear fission and nuclear fusion

Nuclear energy is released by nuclear reactions one is called nuclear fission and another is nuclear fusion. They both involve the disintegration and combination of the elemental nucleus. An atom divides into two or more smaller or lighter atoms is called nuclear fission. Nuclear fusion occurs when two or more atoms join or fuse together to form a large or heavy atom. 

Let us have a deep insight into the comparison between nuclear fission and fusion.

Nuclear fission :

• It is a process of breaking a heavy nucleus with some projectiles into two or more light fragments, with the liberation of a large amount of energy.
• A huge amount of energy required to combine small atoms.
• In this process the emission of radioactive rays possible.
• This process takes place spontaneously at an ordinary temperature.
• The mass number and an atomic number of the daughter elements are considerably lower than that of the parent nucleus.
• This process gives rise to chain-reaction.
• During nuclear fission, neutrons are emitted.
• Nuclear fission can be performed under controlled conditions.
• Fission is used in nuclear power plants.
• Uranium is used as a fuel in power plants.
• Example - Atomic bomb
• Never occurs in natural source in normal cases. 

Nuclear fusion :

• It is a process of fusing two light nuclei into a single nucleus, with the liberation of a large amount of energy.
• Require less energy to divide the atom.
• Does not emit any kind of radioactive rays.
• This process takes place at a very high temperature ( nearly at about >100000 K ).
• The mass number and an atomic number of the product is higher than the starting elements.
• This process does not give rise to chain-reaction.
• During nuclear fusion, positrons are emitted.
• Nuclear fusion cannot be performed under controlled conditions.
• Fusion is an experimental technology for producing power.
• Hydrogen isotopes such as Deuterium and Tritium are the primary fuel used in experimental fusion power plants.
• Example - the Hydrogen bomb
• Happens in a natural source like stars and sun. 

Plasma arc machining

In this article, we have to discuss plasma arc machining how it works and its application and main advantages and also disadvantages of this process.

PAM : 

When a flowing gas is heated sufficiently high temperature to become partially ionized, it is known as 'plasma'. This virtually a mixture of free electrons, positively charged ions and neutral atoms.
PAM is a material removal process in which the material is removed by ionized gas of high temperature (11,000 to 30,000 C) which applied by a high-velocity jet on the workpiece.

Working principle :

The principle of plasma arc machining is in a plasma torch, known as the gun or plasma-Tron, a volume of gas such as H₂, N₂, O₂, etc. is passed through a small chamber in which a high-frequency spark (arc) is maintained between the tungsten electrode (cathode) and the copper nozzle (anode), both of which are water-cooled. In certain torches, an insert gas-flow surface rounding the main flame is provided to shield the gas from the atmosphere. The high-velocity electrons generated by arc collide with the gas molecules and produce dissociation of diatomic molecules of the gas resulting in ionization of the atoms and causing large amounts of thermal energy to be liberated. The plasma forming gas is forced through a nozzle duct of the torch in such a manner as to stabilize the arc. Much of the heating of the gas takes place in the constricted region of the nozzle duct resulting into relatively high exit gas velocity and very high core temperature up to 30,000 C. the plasma jet steams effectively blows the material and the high-velocity gas stream effectively blows the molten metal away.

Accuracy:

• This is a roughing operation to an accuracy of about 15 mm with a corresponding surface finish.
• Accuracy on the width of slots and diameter of holes is ordinary from +0.8 mm to -0.9 mm on 6 to 30 mm thick plates, and +3 mm to -3 mm on 100 to 150 mm thick plates.

Applications of PAM:

• This is chiefly used to cut stainless steel and aluminium alloys. 
• Profile cutting of metals, particularly of these metals and alloys, has been the most prominent commercial application of PAM. 
• PAM has been used successfully in turning and milling of materials which are hard and difficult to machine.

Advantages :

• The main advantages of this process are that it is almost equally effective on any metal, regardless of its hardness of refractory nature.
• There being no contact between the tool and work piece, only a simply supported work piece structure is enough.

Disadvantages :

• The main disadvantages of this process are the metallurgical change of the surface.
• Safety precautions are necessary for the operator and those in near by areas. 
• This adds additional cost. 

Difference between electrochemical series and galvanic series

The electrochemical series is an orderly listing of standard half-cell electrode potential and the galvanic series is an orderly listing of corrosion potential for different metals and alloys. They both are based on thermodynamic analysis. 

Let us have a deep insight into the discuss the electrochemical and galvanic series and the difference between them.  

Electrochemical series :

• Electrode potentials are measured by dipping pure metals in their salt solution of IM concentration, without any oxide films on them.
• The position of a metal in the electrochemical series is fixed.
• It gives no information regarding the positions of alloys.
• The position of metal is permanently fixed in this series.
• this series comprises metals and non-metals.
• It predicts the relative displacement tendencies.
• It is absolute.
• It is quantitative.
• it is a series only for pure metals.
• It is used for theoretical calculations.

Galvanic series :

• This series was developed by studying corrosion of metals and alloys in unpolluted seawater, without their oxide films, if any removed.
• In galvanic series, the position of a given metal may shift.
• Their corrosion can be studied from this series since alloys are included in galvanic series
• The position of metal, when present in the form of an alloy, is different from that of pure metal.
• This series comprises metals and alloys.
• It predicts the relative corrosion tendencies.
• It is relative.
• It is qualitative.
• It is a series for pure metals and alloys also.
• It is used for practical applications.

For video description >> https://www.youtube.com/watch?v=QzGcI2R93jk&t=15s

Difference between orbit and orbital

The orbit and orbit of the two comparable terms often confuse individuals. You must have seen in pictures that an atom is simple, in which electrons are like our planets revolving around a nucleus which may be considered as our sun. Actually, the truth is much more complex. 

Orbits and orbital are different paths of atoms. In this article, let us have a deep insight into the difference between those two similar types of term orbit and orbital.

Orbit :

• Orbit is a fixed circular path, described by a moving electron around a nucleus.
• There is an orbit for any two bodies with a certain mass.
• It has a two-dimensional representation.
• The position and velocity of a moving electron, in an orbit, can be calculated with great accuracy.
• The distance of the orbit from the nucleus for a given electron is fixed.
• The movement of an electron in an orbit is known definitely.
• The maximum capacity of any orbit is 2n² electrons, where n is the number of orbits.
• All orbits are circular and disc-like.
• The concept of the well-defined orbit is against Heisenberg's principle. 
• Orbits are non-directional which is why they can't shape of the molecule.
• An orbit shows an exact position of an electron within an atom.
• Orbits are the definite paths that a moving object traces out.

Orbital :

• Orbital is a three-dimensional region in space around the nucleus, where there is a maximum probability of finding an electron.
• An orbital exists only for an atom and an electron.
• It has a three-dimensional representation.
• The position and velocity of moving electrons, in an orbital, can be determined within the limits of Heisenberg's uncertainty principle.
• It is impossible to know the exact trajectory of an electron in an orbital of an atom.
• Only the probability of finding an electron can be traced with the help of Heisenberg's principle.
• The maximum capacity of any orbital is two electrons.
• Orbital may be spherical (s), dumb-bell (p) and so on in shape.
• The concept of the well-defined orbital is in agreement with Heisenberg's principle.
• Orbitals have a directional character that is why they can account for the shapes of molecules.
• It does not specify an exact position of an electron.
• Orbitals are the regions where the object is likely to be found or move about.

Explore more information: 

1. Difference between PSLV and GSLV

Difference between galvanizing and tinning

Galvanizing is an iron or steel sheet coating process with a thin zinc coat to avoid rusting. Tinning is a coating tin over parts of iron or steel. Both the coating method is used to avoid corrosion. Let us have a deep insight into the difference between galvanizing and tinning. 

Galvanizing :

• Zinc is used for coating.
• Since this method is more electropositive than iron, zinc sacrificially protects the iron and does not allow the iron to pass into the outside solution.
• Zinc continues to protect the underlying iron through galvanic cell action in the galvanized article, even if the zinc layer is punctured or broken somewhere.
• Galvanized containers can not be used to store acidic foods as zinc reacts with extremely toxic zinc-forming food acids.

Tinning :

• Tin is used for coating.
• Due to its noble nature and higher corrosion resistance, Tin protects the base metal, iron from corrosion.
• Tin is non-toxic and protects the iron at the base until the coating is perfect. Any coating break creates fast iron corrosion.
• Tin-coated containers can be used to store any food as tin is non-toxic, protecting the metal from corrosion, and preventing food poisoning.

Difference between addition polymerization and condensation polymerization

There are mainly two types of polymerization. Let us check it out both below. 

What is Addition polymerization?

It is a reaction that produced a product, which is an exact multiple of the original monomeric molecule.

It is also called a chain polymerization.

• It requires two like molecule. 
• Kinetic long linear chain reaction.
• Very fast reaction time. 
• The polymer produced thermoplastic.
• Example - Polythene, Orlon

What is Condensation polymerization?

It is a reaction occurring between simple polar group-containing monomers with the formation of polymer and eliminating of small molecules like water and HCL etc.

• It requires two, unlike molecule. 
• Intermolecular reaction. 
• Slow reaction time. 
• Chemo setting plastic produced. 
• Example - Decron, Bakelite, Nylon 6

Let us have a deep insight into the difference between addition and condensation polymerization. 

Difference : 

• In addition polymerization, only growth reaction adds repeating units one at a time to the chain while in condensation polymerization any two molecular species present can react.
• The number of units decreases steadily throughout the reaction in case of addition polymerization while monomer disappears early in reaction in case of condensation polymerization.
• In case of additional polymerization, a high molecular mass polymer is formed at once, while in the case of condensation polymerization, polymer molecular mass rises steadily throughout the reaction.
• Longer reaction times have a little effect on molecular-weight but give higher yields in case of addition polymerization while in case of condensation polymerization to obtain high molecular-weight and longer reaction time is essential.
• The reaction mixture contains only monomers, high polymers and about 10^-8part of growing chains in case of addition polymerization while all type of molecular species is present at any stage in case of condensation polymerization.

What is calorific value

In this article, we have to discuss the calorific value and different types of units of calorific value and some basic information about that. First of all, we want to know 

What is calorific value?

• The calorific value of a fuel is the total quantity of heat liberated when a unit mass of the fuel is burnt completely. 

Units of calorific value :

Units of calorific value is calories per gram or kilocalories per kg this both used mostly in case of solid or liquid fuel.

In the case of gaseous fuels the unit used is kilocalorie per meter.

It is usually denoted by joules per kilogram.

Calorific value mainly two types :

1. Higher or gross calorific value 
2. Lower or net calorific value 

Advantages and disadvantages of liquid fuels

Liquid fuels are combustible or energy-generating molecules that can be harnessed to generate mechanical energy, generating usually kinetic energy, they also have to take their container shape. Instead of the fluid, the fumes of liquid fuels are inflammable. Let us have a deep insight into the pros and cons of liquid fuels in this article. 

Advantages of liquid fuels :

• They possess higher calorific value per unit mass than solid fuels.
• They burn without forming dust, ash, clinkers etc.
• Their firing is easier and also fire can be extinguished easily by stopping the liquid fuel supply.
• They are easy to transport through pipes.
• They can be stored indefinitely without any loss.
• The flame produced by burning liquid fuels can easily be controlled by adjusting the liquid fuel supply.
• Liquid fuels are generally handled by pipes and one man can easily regulate a large number of furnaces simultaneously.
• They are clean in use and economic in labour.
• Loss of heat to the chimney is very low due to greater cleanliness.
• They require less excess of air for complete combustion.
• They require less furnace space for combustion.
• There is no wear and tear of grate bars and cleaning of fires, unlike solid fuels.
• They can be used as internal combustion fuels.

Disadvantages of liquid fuels :

• The cost of liquid fuel is relatively much higher as compared to solid fuels.
• Costly special storage tanks are required for storing liquid fuels.
• There is a greater risk of fire hazards, particularly in the case of highly inflammable and volatile liquid fuels.
• Liquid fuels give bad odour.
• For efficient burning of liquid fuels, specially constructed burners and spraying apparatus are required.
• Choking for sprayers is a drawback of oil firing.

Advantages and disadvantages of solid fuels

Solid fuel is the various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion.

The solid fuels find little practical application at present because of the problems in handling the fuel as well as in disposing of, the solid residue or ash after combustion. 

Solid fuels compared to gaseous and liquid fuels, solid fuels are quite difficult to handle and storage and feeding are quite cumbersome. Let us have a deep insight into the pros and cons of solid fuels in this article. 

Advantages of solid fuels :

• They are easy to transport.
• They are convenient to store without any risk of spontaneous explosion.
• Their cost of production is low.
• They possess moderate ignition temperature.

Disadvantages of solid fuels :

• Their ash content is high.
• They burn with clinker formation.
• They combustion operations cannot be controlled easily.
• Their cost of handling is high.
• Their large proportion of heat is wasted during combustion.
• Their thermal efficiency is low.
• Their calorific value is lower as compared to that of liquids fuels.
• They require a large excess of air for complete combustion.
• They cannot be used as internal combustion engine fuels.

Characteristics of a good fuel

A good characteristic of good fuel is depending upon the following factors :

• High calorific value 

A fuel should possess high calorific value since the amount of heat liberated and temperature attained thereby depends upon the calorific value.

• Moderate ignition temperature 

Ignition temperature id the lowest to which the fuel must be pre-heated so that it starts burning smoothly.
Low ignition temperature is dangerous for storage and transport of fuel, hence it can cause fire hazards. While high ignition temperature causes difficulty in igniting the fuel, but fuel is safe during storage and transport. Hence, an ideal fuel should have moderate ignition temperature.

• Low moisture content 

The moisture content of the fuel reduces the heating value and involves a loss of money because it is paid for at the same rate as the fuel. Hence, fuel should have low moisture content.

• Low non-combustible matter content

After combustion, the non-combustible matter content generally in form of ash or clinker.
That also reduces the heating value, besides the additional cost of storage, handling and disposal of the waste products produced.

• The moderate velocity of combustion 

If the rate of combustion id low then the required high temperature may bot be possible, because a part of the heat liberated may get radiated, instead of raising the temperature. While too high combustion rates are also not required.

• Products of combustion should not be harmful 

Gaseous products of combustion should not pollute the atmosphere. 

• Low cost 

A good fuel should be readily available in bulk at a cheap rate.

• Easy to transport 

Fuel must be easy to handle, store and transport at a low cost must be necessary. Solid and liquid fuel can easily be transported but gaseous fuel is costly and can even cause fire hazards.

• Combustion should be easily controllable 

Combustion of the fuel should be easy to start or stop. when it is required. Hence, it must be controllable.

• Should no undergo spontaneous combustion 

Spontaneous ignition can cause fire hazards.

• Storage cost in bulk should be low 
• Should burn in air with efficiency, without a highly smoke
• In case of solid fuel, the size should be uniform so that combustion is regular

VTVT engine technology

In this article we will discuss about the VTVT engine techology. So let first you must know the VTVT full form.

VTVT is a technology which has ability to have independent control of the intake and exhaust valve in an internal combustion engine.

VTVT engine technology gives you class mileage and optimum performance for driving experience.

In this technology the timing of intake and exhaust will be depend upon the engine requirement. The timing of both valve will be programmed in different load criteria that the same as Hyundai do in VVT technology.

Function of lubricants

To supply lubricating oil between the moving parts is simply termed as lubrication.

Any substance introduced between two moving or sliding surface with a view to reducing the frictional resistance between them is called lubricants.

Functions of lubricants :

• It reduces surface deformation, wears, and tear because the direct contact between the rubbing surfaces is avoided.
• It reduces the loss of energy in the form of heat.
• It also acts as a coolant.
• It reduces waste of energy so that the efficiency of a machine is enhanced.
• It reduces the expansion of metal by local frictional heat.
• It avoids the seizure of moving surfaces since the use of lubricant minimizes the liberation of frictional heat.
• It avoids or reduces unsmooth relative motion of the moving or sliding parts.
• It reduces the maintenance and running cost of the machine.
• Sometimes it acts as a seal.

Difference between physical adsorption and chemical adsorption

What is Physical adsorption?

It is one in which the adsorbed molecules are held to the surface of the adsorbent by weak physical or van der Waal's forces.

This types of adsorption are completely reversible.

It is also called physisorption or van der Waal's adsorption.

Example: Adsorption of various gases by charcoal belongs to this type.

What is Chemical adsorption?

It is the force which holds the adsorbed molecules is of valence type.

This type of adsorption is irreversible.

It is also called chemisorption or activated adsorption.

Example: Adsorption of oxygen on tungsten is an example of this type.

Let us have a deep insight into the difference between physical and chemical adsorption. 

Difference :

• Chemical adsorption heat evolved is considerably higher than evolved in physical adsorption.
• The heat of adsorption for physical adsorption is 20-40 kcal/mol while 40-400 kcal/mol for chemical adsorption.
• In physical adsorption, molecules are not tightly retained by the adsorbent while molecules are tightly retained by the adsorbent in case of chemical adsorption.
• Adsorption is appreciable only at a temperature below the boiling point of the adsorbate in case of physical while in chemical it occurs at high temperature.
• Multiplayer adsorption occurs in case of physical adsorption while adsorption leads to at most a monolayer in case of chemical adsorption.
• Forces responsible for physical adsorption are very weak while in the case of chemical adsorption it is quite strong.
• In physical adsorption, the rate of adsorption increases with the increase of pressure or of the adsorbate while in case of chemical adsorption rate of adsorption decrease with the increase of pressure or concentration of adsorbate.
• Physical adsorption involves very small or little activation energy while chemical adsorption generally involves appreciable activation energy.
• The equilibrium is established rapidly in a physical case while the establishment of equilibrium requires time in case of chemical adsorption.
• No surface compound takes place in case of physical adsorption while actual surface compound formation between the adsorbent and adsorbate takes place in chemical adsorption.
• Physical adsorption is very specific in nature while chemical adsorption is highly specific in nature.
• Amount of adsorption on a surfaced is more a function of the adsorbate than the adsorbent in case of physical adsorption while the amount of adsorption is characteristics of both adsorbate and adsorbent in chemical adsorption.

You can also check it out : 

• Difference between adsorption and absorption

Difference between adsorption and absorption

Absorption is the process in which a fluid is dissolved by a liquid or a solid whereas adsorption is the process in which atoms, ions or molecules from a substance adhere to a surface of the absorbent. Let us have a deep insight into the difference between adsorption and absorption. 

Adsorption :

• It is a phenomenon of concentration or assimilation of gas or a liquid at the surface of a solid or liquid.
• It is a surface phenomenon.
• It is a fast process.
• Equilibrium is attained easily.
• It depends upon the surface area of the adsorbent. 
• It is an exothermic process.
• It is favoured by low temperature.
• It is steadily increasing and reaches equilibrium.
• It is used in Air conditioning, water purification, synthetic resin. 

Examples : 

• Water vapours adsorbed by silica gel.
• NH₃ is adsorbed by charcoal.

Absorption :

• It is a phenomenon in which the substance assimilated is uniformly distributed throughout the body of the solid or liquid.
• It is a bulk phenomenon.
• It is a slow process.
• Attainment of equilibrium takes some time.
• No such effect is there.
• It is an endothermic process.
• It is not affected by temperature.
• It occurs at a uniform rate.
• It is used in cold storage, ice production, turbine inlet cooling, refrigerant. 

Examples :

• Water vapours absorbed by anhydrous CaCl_2.
• NH₃ is absorbed in water forming NH₄OH.

You can also read about the difference between physical adsorption and chemical adsorption.

Disadvantages of hard water

Disadvantages of hard water in Domestic use :

• Washing :

When we use hard water as a washing purpose the using water does not lather freely with soap and it produces sticky precipitates of calcium and magnesium soaps. This cause wastage of a lot of shops is used. 

• Bathing : Bathing

Hard water does not lather freely with shop solution and produces sticky scum on the body.
Thus, cleansing quality of soap is depressed and lots of water is wasted too.

• Cooking :

Due to the presence of dissolved hardness, the boiling point of water is elevated and it producing slats. Therefore, more fuel and time are required for cooking.

• Drinking :

Hard water causes a bad effect on our digestive system and also the possibility of forming calcium oxalate crystals in urinary tracks is increased.

Disadvantages of hard water in Industrial use : 

• Textile industry :

Hard water cannot produce good quality of lathe. It precipitates of calcium and magnesium soaps adhere to the fabrics. These fabrics when dyed do not produce exact shades of colour.

• Sugar industry :

If hard water used in sugar refining it causes difficulties in the crystallization of sugar and the produced sugar may be deliquescent.

• Dyeing industry :

Because of the use of hard water which yields impure shades and gives spots on the fabrics being dyed.

• Laundry :

Hard water is used in laundry causes much of the soap used in washing and may even cause colouration of clothes.

• Concrete making :

It affects the hydration of cement and the final strength of the hardened concrete.

• Pharmaceutical industry : 

If hard water used for preparing pharmaceutical products like drugs or injection may produce certain undesirable products in them.

Disadvantages of hard water in steam generation in boilers :

If hard water directly fed into the boilers it may cause many troubles following below :

• Scale and sludge formation 
• Corrosion 
• Priming and foaming 
• Caustic embrittlement 

What is flywheel

What is Flywheel?

Answer :

• A heavy revolving wheel in a machine which is used to increase the machine's momentum and thereby provide greater stability or a reserve of available power.

A flywheel is a heavy rotating body that acts as a reservoir of energy. 

Flywheel used in an internal combustion engine to control the speed.

The energy is stored in the flywheel in the form of kinetic energy. 

The function of flywheel :

• To store and release energy when needed during the work cycle.
• To reduce the power capacity of the electric motor or engine.
• To reduce the amplitude of speed fluctuations.

Flywheel materials :

Flywheel made by grey cast iron. 

Now recently, flywheels are made of high strength steels and composites in-vehicle applications. 

Graphite-fiber reinforced polymer ( GFRP ) is one of the excellent choices for flywheels fitted on a modern car engine.