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Tuesday, December 31, 2019

December 31, 2019

Happy New year 2020


“Everything about the future is uncertain, but one thing is for sure that God had already planned all our tomorrows, we just have to trust him today, I heartily wish a beautiful tomorrow for you and your family. Happy New Year 2020!!!”
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Friday, December 27, 2019

December 27, 2019

Natural Resources of India - Part 2

NATURAL RESOURCES OF INDIA - PART 2

FOREST RESOURCES

Benefits  of  Forests
•    Forests produce the requisite raw materials for industries, defence, communications,domestic use and other public purposes.
•    They contribute to the country’s exportsand create a large volume of employment in the primary, secondary and tertiarysectors.
•    They also provide materials like fuelwood, small timber, fodder, etc. fordirect use by the agriculturists.
•    The benefits from forests in the matter of soilconservation, recreation, wildlife, etc. have been well-recognised.

Forests have multifarious uses, some of which can be identified as follows:
•    Trees and forests have many uses, and are, therefore, considered as one ofthe important natural resources of a country. Plants through photosynthesisconvert the  solar energy  into various forms of energy like  food,  fuel,  oilproducts, raw materials for industries, and other indirect sources of renewableenergy, which can be directly used by us. Forests meet nearly 40 per centof our energy needs.
•    The thick foliage-mix, that both trees and shrubs attract, prevents soil erosion,and holds moisture content in both the soil and the atmosphere. These arealso described as hydrological benefits of forests.
•    Forests  meet  the  basic  needs  of  the  poor  people  of the  country  in  manyways. Forests provide 30 per cent of our fodder needs. A large section ofthe country’s population – Ignancy Sachs calls them ‘eco-system people’ –depends on forests for firewood which is basic for human survival. Failure tomeet the basic needs of rural people may put millions of women – who goout to collect the firewood everyday to forests – into serious difficulties
Present  Position
•    Forests  occupy  about  783.7  lakh  hectares  or  about  23.84  per  cent  of  thegeographical area.
•    (Of this dense forest category, i.e., 40 per cent or more of thearea covered by trees, amounts to about 58.0 per cent.)
•    Of these about 433 lakhhectares  or about  61.0  per cent are exploitable;  another  178 lakh  hectares orabout 25 per cent are potentially exploitable.
•    Among the States, Madhya Pradeshhas the maximum forest area of 77,265 sq.km., followed by Arunachal Pradesh(68,045 sq.km.) and Chhattisgarh (56,448 sq. km.).

Mineral resources
Mineral resources are essential natural occurring materials or commodity found on or in the earth in such small amounts which are mined for their potential uses or their intrinsic values.

Types:
Metallic resources are things like Gold, Silver, Tin, Copper, Lead, Zinc, Iron,Nickel, Chromium, and Aluminum. Nonmetallic resources are things like sand, gravel, gypsum, halite, Uranium, dimension stone. A mineral resource is a volume of rock enriched in one or more useful materials.

Minerals:
“A mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes” (Nickel, E. H., 1995). “Minerals are naturally-occurring inorganic substances with a definite and predictable chemical composition and physical properties.”

Example Of A Mineral:
Other common elements in silicate minerals correspond to other common elements in the Earth’s crust, such aluminium, magnesium, iron, calcium, sodium, andpotassium. Some important rock-forming silicates include the feldspars, quartz,olivines, pyroxenes, amphiboles, garnets, and micas.

Mineral resources classification
•    Metallic Mineral Resources
•    Nonmetallic Mineral Resource

FUEL MINERAL RESOURCE
1. Metallic mineral resources: These are minerals resources that contain metal in raw form, their appearances have metallic shine and they can be melted to obtain new products.
Examples: Gold, Silver, Copper, Tin, Iron, Lead, Zinc, Nickel, Chromium, and Aluminium.

2. Nonmetallic mineral resources:  These are minerals that do not contain extractable metals in their chemical composition; they contain nonmetallic shine or lustre in their appearance.
Examples: sand, stone, gravel, clay, gypsum halite, and Uranium.

3. Fuel mineral resource: These are the basic mineral resources in the world. These are primarily gotten from the remains of dead plant and animal, they are often referred to as fossil fuels and are formed from hydrocarbon.
Examples: fossil fuels such as coal, crude oil (petroleum) and natural gas.

STATE WISE:
The principal minerals produced in the State were coal, natural gas (utilised), iron ore, limestone, petroleum (crude), baryites and which together accounted for 53.32% of total value of mineral production in the State during the year 2010-11

INDIAN STATES IN MINERAL WEALTH:

State
Mineral/Metal
Jharkhand
Coal
Odisha
Bauxite (Aluminium Ore)
Odisha
Chromite (Chromium ore)
Odisha
Iron Ore
Odisha
Manganese
Rajasthan
Lead & Zinc
Rajasthan
Calcite (source of marble)
Rajasthan
Gypsum (used in fertiliser, plaster of paris etc.)
Rajasthan
Quartz
Andhra Pradesh
Asbestos
Andhra Pradesh
Limestone
Andhra Pradesh
Mica
Andhra Pradesh
Barytes
Madhya Pradesh
Diamond
Madhya Pradesh
Copper Ore
Karnataka
Gold
Maharashtra
Corundum (source of ruby, sapphire)
Himachal Pradesh
Rock Salt
Rajasthan
Crude Oil
Assam
Natural Gas
Barytes are used as weighting agent for drilling fluids in oil & gas exploration, barium is used in CT Scan


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Natural Resources of India - Part 1
December 27, 2019

Natural Resources of India - Part 1

NATURAL RESOURCES OF INDIA - PART 1

BIOTIC RESOURCES
•    Biotic resources are obtained from living and organic material.
•    These include forest products, wildlife, crops and other living organisms.
•  Most of these resources are renewable because they can regenerate themselves.
•    Fossil fuels are considered as biotic because they are formed from decayed organic matter.
•    Fossil fuels are non-renewable.

ABIOTIC RESOURCES
•    Abiotic resources are obtained from the non-living and non-organic material. Some of the resources, like water and air, are renewable.
•    Other resources like minerals are non-renewable and exhaustible because they cannot be regenerated.
•    Minerals have many categories like metallic, non-metallic and minor minerals.

WATER RESOURCES
•    Water is the most important source of energy in the Indian economy.
•    About 25per cent of electricity generated in the economy is from the hydel sources.
•    Theother important use of water is irrigation.
•    In a country where agriculture givestwists  and  turns  to  the  whole  economy,  provision  of  water  can  make  all  thedifference; it can either stimulate the economic activity or depress it altogether.

The important sources of water can be classified into two parts:
(i) surface water,and
(ii)  ground water. 
•    Surface water  is available from such  sources as  rivers.lakes, etc.
•    Ground water is available from wells, springs, etc.
•    Other sources ofwater which have not as yet been tapped in the country, but nevertheless representa potential source are: saline springs, snow and ice-fields. Surface water sourcesare replenished by rainfall.

Water Issues
The principal issues facing the country are as follows:
(i) Demand for water isincreasing from all sectors,
(ii) Lack of a rational water pricing policy between andwithin sectors is further driving demand,
(iii) Policies and institutions mandated tosolve conflicts are directly or indirectly contributing to further conflicts,
(iv) Newconflicts are increasingly arising within states rather than between states, and
(v)conflicts over ground water are widespread across the country.

National  Water  Policy
The  National  Water  Policy,  2002  was  announced  on April  1,  2002. 
Its  mainfeatures are as follows.
a.    Stress on  maintenance of irrigation projects;
b.    RiverBasin organisations to ensure development and management of inter-state riverbasins; (iii) Calls for dam safety legislation to ensure proper inspection, maintenanceand surveillance;
c.    Calls for national policy for resettlement and rehabilitation ofproject affected people;
d.    Ecology given priority in water allocation; minimumflows in perennial streams mandated;
e.    Provides for participatory approach towater management including water users associations, private sector and moderninformation systems;
f.    Private sector participation should be encouraged inplanning, development and management of water resources projects for diverseuses. It would help in introducing innovative ideas, generating financial resourcesand  introducing  corporate  management  and  improving  service  efficiency  andaccountability to users;
g.    Non-conventional methods of water conservation likerain harvesting, artificial recharge of ground water, inter-basin transfers, desalinisationof brackish or seawater stressed.
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December 27, 2019

FORCE,MOTION & ENERGY

Magme Guru
FORCE,MOTION & ENERGY
FORCE : 
We can say that force is a push or pull acting on an object or energy as an attribute of physical action or movement. This occurs when two entities are in contact. According to the universal law of gravitation, every object in this universe exerts a force on others. The force acting on an object is given by the following parameter: 
  • SI unit of Force: newton(N) or kg.m/s2
  • Symbol of Force: F
  • Type of quantity: Vector quantity
  • Dimensional Formula: M1L1T-2
  • Other units: dyne, pound-force, kilopond, poundal, kip 
Example:  if there are two bodies of mass M and m, and they are kept in such a way that the body with mass m is resting over the body with mass M. In physics we say that these two bodies will exert forces on each other. So we can say that whenever there is an interaction of two or more bodies, force is a part of the interaction. 
MOTION
Whenever a body is moving, we say it is in motion. For instance, if a boy is walking down the street from his school to his home, we will say that the boy is in motion. But imagine if the boy stops for 5 minutes in the way and sits down. If someone asks at that time if the boy is in motion, the answer will be ‘No’. From this, we can infer that the motion of a body is dependent on time. In physics, we say that motion is the change in the position of a body with respect to time. 
FORCE AND MOTION RELATION
Force and motion are deeply related in nature. We can say that force is the cause of motion. Suppose something is moving, we can say that some force must be acting on it or some force must have acted on it which produced this motion.  
If a person is walking, and hence in motion, there must be some force acting on it which is making him move. What is this force? This force is the muscular force of his body. 
Before we delve into the relationship between force and motion, let us first take a quick look into what is meant by force. Simply put, force is either a push or a pull.  
Force is defined as “any interaction that, when unopposed, will change the motion of an object”. By the definition itself, it is clear that force affects the state of motion of an object. 
But what exactly is does state of motion mean? In physics, motion is defined as the change in position with respect to time. In simpler words, motion refers to the movement of a body. Typically, motion can either be described as 
  • Change in speed, or
  • Change in direction.
Sir Isaac Newton was the first person to discover the relation between motion and force. From his studies in force and laws of motion we can come to the following three conclusions: 
  • Force can accelerate the body
  • Force decelerate the body
  • Force can change the direction of the moving body 

Force Can Cause A Body To Accelerate

When force is applied to a body in rest, it starts to move, provided that there is no greater force opposing it. When you throw the ball towards the batsman while playing cricket, the ball starts to move forward from its initial position of rest in your hands. 
When something begins to move from a state of rest, it accelerates. Acceleration can be described as a positive change in velocity over a period of time. 
Similarly, if force is applied in the same direction of movement of a moving object, it accelerates. For example, if you rotate the pedal of a bicycle, it will go faster. 

Force Can Cause A Body To Decelerate
On the other side of the spectrum, if force is applied on the opposite direction of a moving object, it will decelerate or slow down and eventually stop altogether if the force is continued to be applied. For example, when a goalkeeper stops a ball, he causes it to decelerate and stop. 
Force Can Cause A Body To Change Directions
When force is applied on an object in an angle different to its direction of motion, it causes the object to change motion. Almost every ball game uses this principle. The speed can be maintained if the force is applied in a perpendicular angle but the velocity will change. 
Force And Motion Formula
From Newton’s second law of motion, the relationship between Force and motion can be mathematically expressed as: 
  • Force is defined as the product of mass m and acceleration a and is given as F=m.a 
  • Motion is explained using laws of motion and is defined as the particle’s behavior when in motion and is given as   
Where,
    s is the position of the particle
    s0 is the initial position of the particle
    v0 is the initial velocity of the particle
    a is the acceleration
    t is the time 
To wrap up, force and motion are two heavily connected entities. Force can result in the acceleration, deceleration, change in direction or total cessation of motion.
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Thursday, December 26, 2019

December 26, 2019

Mechanics & Properties of Matter - Part 6

Magme Guru

MECHANICS & PROPERTIES OF MATTER - PART 6

BERNOULLI’S THEOREM AND ITS APPLICATIONS 
BERNOULLI’S THEOREM
  • The sum of the energies possessed by a flowing, non-viscous, incompressible liquid at any point throughout its flow is constant when the flow is streamlined. This is called Bernoulli’s theorem.
  • Pressure Kinetic potential energy = a constant. For unit mass of a liquid flowing
  • The above equation shows that when the velocity of the fluid increases, the pressure of the fluid decreases and vice versa.
  • This principle can be illustrated by the following demonstrations. 
Demonstration of Bernoulli’s principle Magic ball :
  • A small ping pong ball is placed in a vertically upward stream of liquid. It is observed that the ball rises to a certain height above the nozzle and stays there against gravity. The ball continues to spin. The velocity of the liquid along the axis of the nozzle is high and hence the pressure is low. As the atmospheric pressure is greater than this pressure, it pushes the ball against the stream without falling down.
  • A monometer is a U-tube containing a liquid. When both arms of a manometer are open to the atmosphere, the liquid level is the same in both arms. When air is blown over one end of the manometer tube the pressure of air decreases and liquid level rises in that arm of the tube. 
Applications of Bernoulli’s theorem
  • Bernoulli’s principle is used in venturimeter to find the rate of flow of a liquid. It is used in pitot tube to find the velocity of a fluid in motion.
  • It is used in a carburettor to mix air and petrol vapour in an internal combustion engine.
  • Bernoulli’s principle is used in an atomiser and filter pump.
  • Wings of an aeroplane are made tapering as shown in fig. The upper surface is made convex and the lower surface is made concave. Due to this shape of the wing, the air currents at the top have a large velocity than at the bottom.
  • Consequently the pressure above the surface of the wing is less as compared to the lower surface of the wing. This difference of pressure is helpful in giving a vertical lift to the plane. 
Effects of Bernoulli’s principle
  • Due to strong wind, storm or cyclone, the roofs are blown off. When a strong wind blows over the roof, there is lowering of pressure on the roof. 
  • As the pressure on the bottom side of the roof is higher, roofs are easily blown off without damaging the walls of the building.
  • A suction effect is experienced by a person standing close to the platform at railway station when a fast train passes the person. This is because the fast moving air between the person and train produces a decrease in pressure and the excess air pressure on the other side pushes the person towards the train.
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December 26, 2019

Mechanics & Properties of Matter - Part 5

Magme Guru

MECHANICS & PROPERTIES OF MATTER - PART 5

VISCOSITY
  • The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress.
  • For liquids, it corresponds to the informal concept of “thickness”;
For example:
  • honey has a much higher viscositythan water

Flow of liquid through a pipe :
  • Let us consider a liquid flowing through a pipe. There are two types of flow namely streamlined flow and tubulent flow.
  • If all the particles of the liquid pass across a point with the same velocity, the flow is said to be stream lined. In this flow, a particle follows the same path throughout its motion.
  • If the particles pass across a point with different velocities, the flow is turbulent. In this flow, a particle does not follow the same path throughout its motion.
  • When a liquid flows slowly and steadily through a pipe, the velocity of the layer of the liquid in contact with the walls of the pipe is zero.
  • As we move towards the axis of the tube, the velocity of the layers gradually increases and reaches a maximum value along the axis of the tube.
  • In the case of streamlined flow of a river, the velocity is maximum for water on the upper layer (surface) of river.
  • The velocity is minimum for water in the bottom most layer.
  • When two parallel layers of a liquid are moving with different velocities, they experience tangential forces which tend to retard the faster layer and accelerate the slower layer.
  • The unit of coefficient of viscosity is N s m–2 or Poise.
  • The values of coefficient of viscosity are different for different liquids.
Coefficient of viscosity of some fluids 
Fluid
Poise
Glycerine
13.4
Castor Oil
9.86
Olive Oil
0.84
Turpentine
0.015
Water
0.018
Mercury
0.0015
Honey
0.2
Blood
0.0027
Air
0.19 X 10-3

Applications of viscous fluids in daily life
  • The motion of falling raindrops is opposed by the viscous force offered by air. Hence the rain drops falls slowly.
  • The viscosity of sea water makes the waves subside during a storm.
  • The motion of objects in fluids depends upon the viscosity of the fluids. The viscous force of water or air opposes the motion of ships, cars, aeroplane etc., Hence their shapes are streamlined in order to minimise the viscous drag on them.
  • Friction reduces the efficiency of a machine by converting mechanical energy into heat energy and causes much wear and tear of the moving parts. Friction is reduced by using lubricants. A lubricant is a substance used to reduce friction. The lubricant forms a thin layer between the two surfaces in contact. It also fills the depressions present in the surfaces of contact and reduces friction considerably. In light machinery, thin oils (e.g., clock oil) with low viscosity are used. In heavy and fast moving machinery solids or thick highly viscous oils (e.g., grease) are used. By adding long chain polymers with lubricating
  • oil, its coefficient of viscosity is kept constant even at high temperatures. 
A good lubricant should have the following
  • It should be able to spread and fill up the minute depressions in the surfaces.
  • It should be chemically inert and should not undergo any decomposition at high
  • temperature.
  • It should be capable of conducting away the heat produced by friction.
  • If the arteries and veins of human body contract and become hard, their diameters decrease. Hence the flow of blood is affected due to the viscosity of blood and the blood pressure increases. This affects the functioning of heart. When the temperature of human body increases during fever, the coefficient of viscosity of blood decreases. This increases the blood circulation and the normal heart functioning is maintained.
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December 26, 2019

Mechanics & Properties of Matter - Part 4

Magme Guru

MECHANICS & PROPERTIES OF MATTER - PART 4

MOLECULAR FORCES
•    Surface Tension is essentially a molecular phenomenon. There are two types of molecular forces of attraction Adhesive force and Cohesive force.
•    Forces between molecules of different substances are called adhesive forces.
•    The adhesive force is different for different pairs of substances.
•    Gum or glue is an adhesive. The force of attraction between gum and paper is an adhesive force.
•    Forces between molecules of the same substances are called cohesive forces. The cohesive forces are short range forces and therefore they are effective only up to a very small distance.
•    The adhesion of water to glass is stronger than the cohesion of water. On the other hand, the cohesion of mercury is greater than its adhesion to glass.
•    The maximum distance at which the molecules can attract each other is called molecular range.
•    The molecular range is of the order of 10-8

Explanation of surface tension on the basis of molecular theory :
•    A sphere drawn with the molecule as centre and radius equal to the molecular range is called the sphere of molecular influence.
•    The molecular forces are effective within this sphere of molecular influence. Therefore all the molecules lying within this sphere of molecular influence exert a force of attraction on the molecule at the centre.
•    These molecular forces are responsible for surface tension.

ILLUSTRATIONS OF SURFACE TENSION
•    The following activities illustrate surface tension of liquids.

CAPILLARY RISE
•    A glass tube with a very fine uniform bore is called a capillary tube.
•    When a capillary tube is dipped vertically into a liquid contained in beaker, the liquid immediately rises or falls in the tube.
•    q is the angle of contact for the given pair of solid and liquid. The angle of contact is defined as the angle between the tangent to the liquid surface at the point of contact and the solid surface inside the liquid.
•    If the angle of contact is acute, the level of liquid inside the capillary tube is higher than that in the beaker.
•    This capillary rise is observed in the case of water. If the angle of contact is obtuse, the level of liquid inside the tube is lower than that in the beaker.
•    This capillary fall is observed in mercury ( 140°). For water in silver tube, = 90° and h = 0.
•    The level of liquid remains the same. For pure water and clear glass = 0°.
•    This phenomenon of rise or fall of liquid in a capillary tube is called capillarity and this capillarity is due to the property of surface tension of liquids.

Examples of capillary action
•    The rise of sap in trees and plants.
•    The rise of kerosene or oil in the wick of an oil lamp or stove. The absorption of ink in a blotting paper.
•    Sandy soil is drier than clay : The interspaces between the particles of the clay form finer capillaries and water rises to the surface quickly.

Applications of Surface Tension
•    Capillary rise is responsible for rising of water in plants. In an oil lamp or stove the oil rises up the wick due to capillarity.
•    The purpose of applying soap to clothes is to spread it over large area
•    When soap is dissolved in water the surface tension of water is lowered. Surface tension always opposes the spreading of a liquid. By reducing surface tension we facilitate the liquid to spread over larger surfaces. This is why soap is used for washing. For the same reason The paste spreads more freely in the mouth and facilitates cleaning of the mouth.
•    When we pour oil on the surface of water it lowers the surface tension of water. Hence the mosquito breed sinks down and perishes.
•    In voyage at the high seas, when there are violent waves the sailors pour tins of oil around their boats or ships. Due to oil the surface tension of sea water is reduced thereby the height of water waves is also reduced.
•    A pen nib is split at the tip to provide the narrow capillary and the ink is drawn upto the tip continuously.
•    When molten lead is allowed to fall through the end of a narrow tube, lead drops assume spherical shape due to surface tension. In factories lead shots are manufactured in this way. Rain drops assume spherical shape due to surface tension of water.
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December 26, 2019

Mechanics & Properties of Matter - Part 3

Magme Guru
MECHANICS & PROPERTIES OF MATTER - PART 3

GRAVITATION :
·  Planetary motion is one of the important periodic motions. According to Ptolemy’s (2nd century A.D.) geocentric theory, the earth was assumed to be at the centre of the universe and the sun, the moon, the planets and even the stars were thought to move around in complicated paths.
   Later Copernicus proposed a new theory called heliocentric theory (15 century A.D.) In this theory the sun was considered to be at the centre and the earth and other planets revolve around the sun in circular orbits of different radii.
    Copernicus also believed that the earth rotates on its axis once every day. The famous Indian mathematician and astronomer Aryabhatta who lived in the fifth century A.D. perceived the earth’s rotation on its axis.
·  Later in 16th century Tycho Brahe made very careful and accurate measurements of the motion of the planets and the sun. Based on the study of Tycho Brahe, another astronomer Kepler laid the foundation of modern astronomy.
Kepler deduced three laws which accurately described the motions of planets about the sun.

These laws formed the basis of the famous Newton’s law of universal gravitation.
1.    Kepler’s laws First law (Law of orbits)
·        Each planet moves around the sun in an elliptical orbit with the sun at one of its foci.
2.     Second law (Law of areas)
   As the planet moves in its orbit, a line drawn from the sun to the planet sweeps out equal areas in equal intervals of time.
3.     Third law (Law of periods)
     The squares of the periods of revolution of the planets are        proportional to the cubes of their mean distances from the sun.
           The planets with the mean distances from the sun, their orbital periods and velocities are listed in the table.



LAWS OF PERIODS 

Name of the Planet
Time Period (Yrs)
Mean Distance from the Sun R (x 109m)
Mean Velocity ( x 103 m/s-1)
( x10-25)
Mercury
0.241
57.91
47.875
2.991
Venus
0.615
108.21
35.056
2.985
Earth
1
149.6
29.806
2.987
Mars
1.881
227.94
24.144
2.988
Jupiter
11.862
778.3
13.072
2.988
Saturn
29.458
1427
9.651
2.986
Uranus
84.015
2869
6.804
2.99
Neptune
164.788
4498
5.438
2.984
About 100 years later, Newton demonstrated that Kepler’s laws were the consequence of a simple force that exists between any two masses.
Newton’s law of gravitation and laws of motion, provide the basis for the motion of planets and satellites.

NEWTON’S UNIVERSAL LAW OF GRAVITATION

Everybody in the universe attracts every other body with a force which is directly proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them.

SURFACE TENSION 
  • Have you seen insects like ants, water-spider walking on the surface of water ? You have seen mosquitoes sit and move freely on the surface of stagnant water.
  • When we sprinkle water at the roots of trees and shrubs, the sprinkled water gradually rises to their branches upwards.
  • Surface tension of a liquid is defined as the tangential force per unit length acting at right angles on an imaginary line drawn on the surface of the liquid.
  • It’s unit is N m-1.
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