Wednesday, 22 March 2017

Types of Nozzle in IC Engine : Pintle Nozzle, Single Hole Nozzle, Multihole Nozzle, Pintaux Nozzle

Today we will learn about types of nozzle used in IC engines. Nozzle is that part of an injector through which the liquid fuel is sprayed into the combustion chamber. It is used in Diesel engine in which fuel is drawn separately through injector at end of compression stroke and air is drawn into cylinder in suction stroke. The nozzle used in IC engine should follow following functions.

  • It should automizate fuel. This is a very important function since it is the first phase in obtaining proper mixing of the fuel and air in the combustion chamber.
  • Distribute the fuel in require area within the combustion chamber.
  • To prevent fuel from impinging directly on the walls of combustion chamber or piston. This is necessary because fuel striking the walls decomposes and produces carbon deposits. This causes smoky exhaust as well as increase in fuel consumption.
  • To mix the fuel with air in case of non-turbulent type of combustion chamber.


Types of Nozzle in IC Engine:

The design of nozzle must be such that the liquid fuel forced through the nozzle will broke up into fine droplets, or atomize, as it passes into the combustion chamber. This is the first phase in obtaining proper mixing of the fuel and air in the combustion chamber. Various types of nozzles are used in IC engines. These types are as follow.

Types of Nozzle in IC Engine : Pintle Nozzle, Single Hole Nozzle, Multihole Nozzle, Pintaux Nozzle

The Pintle Nozzle:

In this type of nozzle the stem of nozzle valve is extended to from a pin or Pintle which protrudes through the mouth of the nozzle. The size and shape of the Pintle can be varied according to the requirement. It provides a spray operating at low injection pressures of 8-10MPa. The spray cone angle is generally 60 degree. The main advantage of this nozzle is that it avoids weak injection and dribbling. It prevents the carbon deposition on the nozzle hole.

The Single Hole Nozzle:

In this type of nozzle at the center of the body there is a single hole which is closed by the nozzle valve. The size of the hole is usually of the order of 0.2 mm. Injection pressure is of order of 8-10MPa and spray cone angle is about 15 degree. One of the major disadvantages of this nozzle is that they tends to drible. Besides, their spray angle it too narrow to facilitate good mixing unless higher velocities are used.


The Multi Hole Nozzle:

This nozzle consists of a number of holes bored in the tip of the nozzle. The number of holes varies from 4 to 18 and the size from 35 to 200 micro meters. The hole angle may be from 20 degree upwards. These nozzles operate at high injection pressure of the order of 18 MPa. Their advantage lies in the ability to distribute the fuel properly even with lower air motion available in open combustion chambers.

Pintaux Nozzle:

This type of nozzle is a type of Pintle nozzle which has an auxiliary hole drilled in the nozzle body. It injects a small amount of fuel through this additional hole which is called pilot injection in upstream direction slightly before the main injection. The needle valve does not lift fully at low speeds and most of the fuel is injected through the auxiliary hole. The main advantage of this nozzle is better cold starting performance. A major drawback of this nozzle is that its injection characteristics are poorer than the multihole nozzle.

This is all about types of nozzle used in IC engines. If you have any query regarding this article, ask by commenting. If you like this article, don’t forget to share it on social networks.
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Tuesday, 21 March 2017

Jigs and Fixture : Working, advantages and Differences

Today we will discuss about what are Jigs and Fixture, working, advantages and also difference between them. Before discussing about it first you should learn the concept of Jigs and Fixtures. We know that machining is the process of removing metal by the moving or stationary work piece by use of tool. This process is done on some kind of machining like lathe, milling, drilling etc. When the work piece is smaller and simpler it can be easily mounted on the machine and we do not require any other mechanism to hold the work piece (concept of Fixture) and guide the tool (concept of Jigs).  But in some cases when the work piece is heavier and machining process is difficult some external mechanisms are used to hold the work piece on machine and also guide the tool so accurate machining can be done on work piece. These devices are known as jigs and fixture.  

Jigs and Fixtures are production tools used to accurately manufacturing duplicate and interchangeable parts. They are specially designed so that a large number of components can be machined or assembled identically, and to ensure interchangeability of components. They eliminate the necessity of a special set up for each individual part.

  • Jigs and fixtures are precision tools.
  • They are expensive to produce because they are made to fine limits from materials with good resistance to wear.
  • They must be properly stored or isolated to prevent accident damage, and they must be numbered for identification for future use.

Jigs and Fixtures:

What is Jig?

A jig is a device in which a component is held and located for a specific operation  in such a way that it will guide one or more cutting tools to the same zone of machining. The usual machining operation for jigs are drilling and reaming. Jigs are usually fitted with hardened steel bushings for guiding drills or cutting tools. The most common jigs are drilling jigs, reaming jigs, assembly jigs etc. when these are used they are usually not fastened to machine tools or table but are free to be moved so as to permit the proper registering of the work and the tool.
 
Jigs and Fixture : Working, advantages and Differences
Jig

What is Fixture?

A fixture is a production tool that locates, holds and supports the work securely in a fixed orientation with respect to the tool so that the required machining operations can be performed. Fixtures vary in design from relatively simple tools to expensive complicated devices. There are most frequently attached to some machine tool or table. The most common fixture are milling fixtures, broaching fixtures, assembly fixture etc.
Jigs and Fixture : Working, advantages and Differences
Fixture

 Advantages of Jigs and Fixtures:

Jigs and fixtures are used in mass production of identical parts. They gives following advantages.
  • They improve productivity.
  • It gives rapid production work.
  • It reduced manufacturing costs.
  • Complex and heavy components can be easily machined.
  • Owing to high clamping rigidity, higher speed, feeds and depth of cut can be used.
  • Jigs and fixtures are increased machining accuracy.
  • It reduces in the expenditure due to inspection and quality control of finished components.


Difference between Jigs and Fixture:

Jigs and Fixture : Working, advantages and Differences

S.No.

Jigs

Fixtures

1.
Jigs incorporate bushes that guide the tools.
Fixture holds the component being machined with the cutters working independently.
2.
Jigs are used on drilling, reaming, tapping and counter boring operations.
They are used in connection with turning, milling, grinding, shaping, planning, and boring operation.
3.
Jigs are depended on operation.
Fixtures are dependent on specific machine tools.
4.
They are lighter than fixture.
Fixture are heavier in construction and bolted rigidly  on the machine table.
5.
They are more costly compare to fixture.
They are less costly.
6.
They are not fixed on machine table.
They are fixed on machine table.



This is all about Jigs and Fixtures uses, advantages and difference between them. If you have any query regarding this article, ask by commenting. If you like this article, don’t forget to share it on social networks.
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Monday, 20 March 2017

Difference between Battery Ignition System and Magneto Ignition System

Today we will difference between Battery Ignition System and Magneto Ignition System. These both are major ignition system used in both light and heavy engines. In battery ignition system a battery and ignition coil is used to generate spark at spark plug but in magneto ignition system necessary energy is generated by its own electric generator. It is mounted on the engine and replaces all component of battery ignition system except spark plug. We have discussed both of these in previous articles. Today we will differentiate them.
Difference between Battery Ignition System and Magneto Ignition System

Difference between Battery Ignition System and Magneto Ignition System:

S.No.

Battery Ignition System

Magneto Ignition System

1.
As the name implies, battery is necessary in this type of ignition system.
No battery is needed in this type of ignition system. It has its own electric generator.
2.
It is difficult to start when the battery is discharge.
There is no such problem because no battery is used.

3.
It required high maintenance due to battery.
It required less maintenance.
4.
In battery ignition system current for primary circuit is obtain by battery.
In magneto ignition system, required electric current is generated by the magneto, which is an electric generator.
5.
Spark strength does not depend on speed of engine due to current is supplied by battery.
Spark strength depends on speed of engine due to magneto.

6.
Good spark is available at low speed.
During starting or at low speed, quality of spark is poor.
7.
Efficiency of system decreases with the reduction in spark intensity as engine speed rises.
Efficiency of the system improves as the engine speed rises due to high intensity spark.
8.
Battery ignition system occupies more space.
Compare to battery ignition system, magneto ignition system requires less space.
9.
Commonly employed in cars and light commercial vehicles.
It is mainly used in racing cars and two wheelers.


These are all major differences between battery ignition system and magneto ignition system. If you have any query regarding this article, ask by commenting. If you like this article, don’t forget to share it on social networks. 
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Sunday, 19 March 2017

Magneto Ignition System : Parts, Function, Working, Advantages and Disadvantages

Today we will discuss about Magneto Ignition System. In my last post we have learnt about Battery Ignition System its parts and working but the Magneto ignition System is completely differ from it. Magneto is a special type of ignition system with its own electric generator to provide necessary energy for the ignition system. It replaces all component of battery ignition system except spark plug. Today we will complete study about this system.

Magneto Ignition System : Parts, Function, Working, Advantages and Disadvantages

Magneto Ignition System:

Parts of Magneto Ignition System:

Magneto:

It is the major part of this type of ignition system because it is source of energy. A magneto is  a small electric generator which is rotate by the engine and is capable of produce a very high voltage and does not need battery as a source of external energy. The magneto contains both primary and secondary winding thus it does not require a separate coil to boost up the voltage required to operate the spark plug. There are two types of magneto. First one is known as armature rotating type and other one is known as magnet rotating type. In the first type, the armature rotates between the stationary magnate. On the other hand in second type armature is stationary and the magnates are rotating around armature.

Distributor:


Distributor is used in multi cylinder engine to regulate spark in each spark plug at correct sequence. It distribute ignition surge in individual spark plug in correct sequence. There are two types of distributor. One is known as carbon brush type and the other one is gap type. In carbon brush type carbon brush carried by the rotor arm sliding over the metallic segment embedded into the distributor cap or molded insulating material. This makes electric connection or secondary winding with spark plug. In gap type distributor electrode of rotor arm pass close to but does not make contact with the distributor cap. So there is no wear of electrode.

 

Spark Plug:


A spark plug generally has two electrodes which are separated with each other. A high potential discharge flow through it which generate spark and ignite the combustion mixture in cylinder. It mainly consist two electrodes a steel shell and an insulator. The central electrode connected with the supply of ignition coil. It is well insulated with the outer steel shell which is grounded. There is a small air gap between steel shell and central electrode, between which spark is generated. The electrode usually made by high nickel alloy so it can withstand with high temperature and corrosion resistance.  

 Capacitor:


It is a simple electrical capacitor in which two metal plate are separated by an insulating material with a distance. Commonly air is used as insulating material but for particular technical requirement some high quality insulating material is used.


Working of Magneto Ignition System:

The working principle of magneto ignition system is same as battery ignition system except in the magneto ignition system Magneto is used to produce energy except battery.  The diagram of four cylinder magneto ignition system is as follow.
Magneto Ignition System : Parts, Function, Working, Advantages and Disadvantages
MAGNETO IGNITION SYSTEM

  • First when the engine starts or during cranking magneto rotate which generates a very high voltage.
  • The ignition capacitor connected in parallel with contact breaker. One end of magneto winding is also grounded through contact breaker.
  • The cam regulates the contact breaker. Wherever the breaker open, current flows into condenser, which charged the condenser.
  • As the condenser become charger the primary current falls and the magnetic field collapses. This will induces a much higher voltage in condenser.
  • Now this high voltage EMF produce spark at correct spark plug through distributor.


As the engine speed is low at starting, the current generated by the magneto is quite small. As the engine speed increases the flow of current also increases. Thus with magneto ignition system there is always starting problem and sometimes a separate battery needed for stating. This ignition system is best suited at high speed so it is used in racing cars, aircraft engines etc.

Advantages and Disadvantages:

Advantages:

1. This system is more reliable at medium and high speed.               
2. It is more reliable because no battery is used.
3. It requires less frequently maintenance.

Disadvantages:

1. It has starting problem due to low cranking speed at starting.
2. It is more expensive compare to battery ignition system.
3. There is possibility of misfire due to leakage because wiring carry vary high voltage.



This is all about magneto ignition system parts, working, advantage and disadvantages. If you have any query regarding this article ask by commenting. If you like this article, don’t forget to share it on social networks. 
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Saturday, 18 March 2017

Battery Ignition System : Parts, Function, Working, Advantages and Disadvantageas

Today we will discuss about battery ignition system main parts, function, working, advantages and Disadvantages. Most of SI engine used battery ignition system. In this system a 6 volt or 12 volt battery used to produce spark. Passenger cars, light truck, motorcycles and large stationary engines are fitted with this system.

Battery ignition system:

Battery Ignition System : Parts, Function, Working, Advantages and Disadvantageas

Main Parts of battery ignition system:

Battery


A battery is used to provide energy for ignition. It is work as storage of energy and charged by dynamo, which is driven by engine. It converts chemical energy to electric energy. Two types of battery used in spark ignition system, lead acid battery and alkaline battery. The first one is used in light duty commercial vehicle and the other one is used in heavy duty commercial vehicle. It is housed in primary side of ignition coil.


Ignition switch


It is used to turn on and off the ignition system. Battery is connected to the primary winding of ignition coil by ignition switch and ballast resistor.


Ballast resistor


It is connected in series with primary winding to regulate current in primary winding. It is used to prevent injury due to overheating of ignition coil. It controls the current passes through primary winding. It is made by iron. Iron has property of increase electrical resistance rapidly by increase in temperature at certain limit. This additional resistance resists flowing current which control the temperature of ignition coil.


Ignition coil


Ignition coil is the main body of battery ignition system. The purpose of ignition coil to step up the battery voltage (6 or 12) to a high voltage, which is sufficient to produce spark at spark plug. It consist a magnetic core or soft wire or sheet, and two electrical winding called primary winding and secondary winding. The primary winding has generally 200-300 turn and the end are connected to exterior terminal. The secondary has almost 21000 turns of copper wire which is insulated to withstand with high voltage. It is located inside the primary winding and its one end connected to secondary winding and other end is grounded either to primary winding or to the metal case. This entire unit is enclosed in a metal container which makes it a compact unit.


Contact breaker


This is a mechanical device making and braking the primary circuit to ignition coil. When the points are closed current flow in ignition coil and when it open, flow of current stopped.


Capacitor


It is a simple electrical capacitor in which two metal plate are separated by an insulating material with a distance. Commonly air is used as insulating material but for particular technical requirement some high quality insulating material is used.


Distributor


Distributor is used in multi cylinder engine to regulate spark in each spark plug at correct sequence. It distribute ignition surge in individual spark plug in correct sequence. There are two types of distributor. One is known as carbon brush type and the other one is gap type. In carbon brush type carbon brush carried by the rotor arm sliding over the metallic segment embedded into the distributor cap or molded insulating material. This makes electric connection or secondary winding with spark plug. In gap type distributor electrode of rotor arm pass close to but does not make contact with the distributor cap. So there is no wear of electrode.

  

Spark Plug


A spark plug generally has two electrodes which are separated with each other. A high potential discharge flow through it which generate spark and ignite the combustion mixture in cylinder. It mainly consist two electrodes a steel shell and an insulator. The central electrode connected with the supply of ignition coil. It is well insulated with the outer steel shell which is grounded. There is a small air gap between steel shell and central electrode, between which spark is generated. The electrode usually made by high nickel alloy so it can withstand with high temperature and corrosion resistance.   


Working of Battery Ignition System:

In the battery ignition system ignition coil stores the energy in form of magnetic field and deliver it at the instant of ignition, in form of high voltage current with high tension wire to correct spark plug. The diagram of four cylinder battery ignition system is as follow.
Battery Ignition System : Parts, Function, Working, Advantages and Disadvantages

  • First low voltage current flow form battery to the primary coil through ignition switch and ballast resistor.
  • Ballast resistor regulates the temperature of ignition coil by regulating current passing form it.
  • The ignition capacitor connected in parallel with contact breaker. One end of secondary winding is also grounded through contact breaker.
  • When the ignition switch is closed, the primary winding of the coil is connected to the positive terminal, and current flow through it known as primary current.
  • The current flows form primary coil produces a magnetic field which induces an EMF in secondary coil.
  • The cam regulate the contact breaker. Wherever the breaker open, current flows into condenser, which charged the condenser.
  • As the condenser become charger the primary current falls and the magnetic field collapses. This will induces a much higher voltage in condenser.
  • Now the condenser discharge into the battery which reverse the direction of both primary current and magnetic field. This will induce a very high EMF in secondary winding.
  • Now this high voltage EMF produce spark at correct spark plug through distributor.


Advantages and Disadvantages:

Advantages:

1. At the time of starting or at low speed good spark is available.
2. The battery which is used to generate spark can be used to light other auxiliary like headlight, tell light etc.
3. Initial expenditure is less and it has low maintenance cost.          
4. Ignition system is not affected by adjusting spark timing in battery ignition system.  

Disadvantages:

1. Time available of built up the current and stored energy is decrease as speed of engine increases.
2. Contact breaker subjected to both electrical and mechanical wear which results short maintenance interval.
3. The primary voltage decreases as the engine speed increase. So it is not fully reliable of high speed engine.


It is all about battery ignition system parts, principle, working, advantages and disadvantages. If you have any query regarding this article, ask by commenting. If you like this article doesn’t forget to share it on social networks. 
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Friday, 17 March 2017

Tool Wear : Flank Wear, Crater Wear and Nose Wear Mechanism

Today we will discuss about tool wear, is mechanism, types and mainly focus on Flank wear, Crater wear and Nose Wear. Tool wear is common phenomenon is metal cutting. Before discussing about tool wear we should learn about how a tool fails. The cutting tools fail due to following three conditions.

1. Breakage of tool due to excessive shock and force.
2. Tool wears due to plastic deformation or change in chemical of physical condition of tool.
3. Gradual wear like flank wear, crater wear etc.

The first two wear breakage wear and wear due to plastic deformation are very harmful for both machine and work piece. So it should be totally eliminated by using favorable condition and taking high factor of safety.
Tool Wear : Flank Wear, Crater Wear and Nose Wear Mechanism

Gradual wear can’t be totally eliminated but can be reduce. Today we will discuss about this wear causes, mechanism, types like flank wear, crater wear, nose wear, favorable condition etc. Generally tools are made by hard and brittle material. It cuts material by plastic deformation. When sharp edge tool rubs over the work piece, shear off some material and give desire shape of work piece. Due to this rubbing and many other mechanism tool also worn out, which is known as tool wear. Every tool has specified tool life which is depends on its material, work piece material, cutting conditions etc. Today we will discuss all about these.

Tool Wear:

Tool Wear Mechanism:


1. Abrasive wear:

This wear is depends upon work hardening of work piece. When the tool cut the work piece, some small chips are forms which act as hard particle. These hard particle acts as small cutting edge like grinding wheel, which cause tool wear.

2. Adhesion wear:


This tool wear is due to sliding of chips over the tool. The chips forms by metal cutting are hard and have high temperature. This is wear is due to rubbing of these chips over the tool. This wear cause due to high friction and high temperature of chips flowing over tool face. 


3. Diffusion:


Diffusion means diffuse of hard metal into soft metal due to high temperature of contact surface between hard material and soft material. In tool wear chips act as hard material and tool act as soft material.


4. Oxidation:


Oxidation mean diffuse of oxygen particle tool face. It is also depend surface temperature of tool and tool material. 


5. Chemical decomposing:


Due to high temperature and pressure there is change in chemical composition of tool which reduces its life.


Types of Tool Wear:

Tool Wear : Flank Wear, Crater Wear and Nose Wear Mechanism
Flank Wear, Crater Wear and Nose Wear

1. Flank wear:

Flank wear is due to abrasive action of discontinuities like debris from built up edge etc. It wears out side and end flank of the tool. It is occur at tool work-piece interface. This wear predominates at low speed.    

2. Crater wear:

Crater wear generally occur in machining ductile material due to abrasion and diffusion of metal at face of tool. It is occur at face at a short distance from cutting edge. This wear predominates at high speed.

3. Nose wear:

Nose wear are consider as separate part of wear. It wears out the tool corner. It is the matting part of flank and face which is combination effect of crater wear and flank wear. It is considered as separate wear because the tool corners are very important for proper cutting of work-piece.

Tool wear can be reduce by proper cooling and lubricate because the major cause of tool wear is friction and temperature rise due to friction. Lubricate reduce friction between chips and tool which reduce tool wear tool. It can also be reduced by using high hardness and abrasion resistance tool and high resistance to adhesion and diffusion.

Today we have discussed about tool wear mechanism types like flank wear, crater wear, nose wear its favorable condition etc. If you have any doubt about this article asks by commenting. If you like this article, don’t forget to share it on social networks.
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Thursday, 16 March 2017

LPG vs Petrol Engine

Today we will learn about main difference between LPG vs Petrol powered engine. We know that both petrol and LPG are used as fuel in SI engine. Mainly SI engine are power by petrol but due to low cost of LPG and negligible effect on power, most of people convert their Petrol Power engine into LPG power engine.

LPG vs Petrol Engine

There are many other differences between these two engines except cost. These are as follow.

Difference between LPG vs Petrol Engine:

S.No.

Petrol Engine

LPG Engine

1.
Fuel Consumption in Petrol engine is less when compared to LPG.
Engine running on LPG results 10% increase in consumption compare to petrol engine.
2.
Petrol has odour or it smell badly.
LPG is odourless or it has no smell. But due to identified leakage Ethyl Mercaptan added in it which also smell badly.
3.
Octane rating of petrol is 81.
Octane rating of LPG is 110 which is more than petrol, So there e is less possibility of detonation.
4.
Compare to LPG Engine, petrol engines are not smooth running.
Due to higher octane number less knocking LPG engines are running smoothly compare to petrol engines.
5.
Lead is added in petrol engine to increase octane rating, which is harmful for environment.
LPG is lead free so it is ecofriendly.

6.
When petrol passes over the oil rings, it washes out the lubricant film from the upper cylinder surface. It causes lack of lubricant which increases wear and tear. So the life of petrol engine is less compare to LPG engine.
LPG does not wash out lubricant film, hence the life of LPG engine is increased by 50%.
7.
It forms carbon deposit on the spark plugs, so the life of spark plug is shorter.
LPG does not deposits carbon on spark plug so the life of spark plug is more than petrol engine.
8.
Carburetor is used to mix air fuel mixer in proper ratio in petrol engine.
Vaporizer used to mix air fuel in proper ratio in LPG engine. It reduce the LPG pressure, vaporize it and supply it according to engine requirement.


This is all about LPG vs Petrol engines. If you have any query regarding this article, ask by commenting. If you like this article don’t forget to share it on social networks.
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Friday, 10 March 2017

Difference between Fission and Fusion

Today we will learn about difference between fission and fusion. Fission and Fusion both are nuclear reactions which are use to create huge amount of energy. Nuclear fission is the process that occurs when a Newton collides with the nucleus of certain of the heavy atoms, causing the original nucleus to split into two or more unequal fragments which carry off most of the energy of fission as kinetic energy.

Difference between fission and fusion


Nuclear fusion is the process of combining or fusing two lighter nuclei into a stable and heavier nuclide. In this case also large amount of energy is released because mass of the product nucleus is less than the masses of the two nuclei which are fused.

Both fission and fusion are used to create energy. There are many differences between them which are as follow.

Difference between Fission and Fusion:


S.No.

Fission

Fusion

1.
When heavy and unstable nuclear is bombarded with neutrons, the nucleus splits into fragments of equal mass and energy is released.
Some light element fuse together with release of energy is known as fusion.
2.
Nuclear reaction residual problem is great.
In fusion residual problem is much less.
3.
Fission involve more amount of radioactive material in fission reactor.
Fusion has a possible advantage is that the total amount of radioactive material in a working fusion reactor is likely be very much less that that in a fission reactor.
4.
It has higher risk of health hazarded in case of accident.
Because of lesser radioactive material than fission, health hazards are much less.
5.
About one thousandth of the mass is converted into energy.
It is possible to have four thousandths of mass converted into energy.
6.
It is possible to construct self sustained fission reactors and have positive energy released.
It is extremely difficult to construct controlled fusion reactors.
7.
Fission can obtain manageable temperature.
It involves unmanageable temperature like 30 million degrees for fusion process.
8.
Raw fissionable material is not available in plenty.
Reserves of deuterium, the fusion element, are available in great quantity.


Today we have discussed about difference between fission and fusion. If you have any query regarding this article, ask by commenting.
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