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Wool

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Page 1: Wool
Page 2: Wool

Wool is the fiber derived from the hair of

animals of the Caprinae family, principally

Sheep, but the hair of certain species of

other mammals such as goats, llamas and

rabbits may also be called wool.

Wool has two qualities that distinguish it

from hair or fur: it has scales which overlap

like shingles on a roof and it is crimped; in

some fleeces the wool fibers have more

than 20 bends per inch.

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In the thirteenth century, the wool trade was the

economic engine of the Low Countries and of Central

Italy; by the end of the following century Italy

predominated.

Due to decreasing demand with increased use of

synthetic fibers, wool production is much less than what it

was in the past.

The collapse in the price of wool began in late 1966 with

a 40% drop; with occasional interruptions, the price has

tended down.

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• Sheep were one of the first animals domesticated by humans.  These sheep looked very different from modern animals.  They had a long hair-like outer guard layer with a more downy insulation layer underneath resembling what we think of as wool.  They shed this coat in the spring.  Primitive people collected the fiber finding it to be of great use, learned to spin.  Thus the wool industry was born.

• The first sheep were brought to the North American continent in 1493 on the second voyage of Columbus

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• New England was the first area to establish a spinning and weaving industry.  Initially begun in homes, later in small factories, it continued to grow.  Eventually the first water powered textile factories were established in 1788.

• The industry was greatly boosted during the Civil War by a great demand for wool to make soldier's uniforms.  Breeders use imported Merino sheep to improve native stock to help meet the demand

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TodayToday

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• Wool is 5% of the world's textile industry.

• Most of our domestic breeds produce 4-5 times more wool than sheep initially brought to the United States greatly due to the influence of the Merino.

• All domestic wool produced finds use in a variety of products.  However, because of defects, contamination, and other quality problems, it is of lower value than some imported wool.

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• Mills rely on imported wool to maintain operation (about 76%).

• The mills require higher quality fiber to maximize production due to modern methods and equipment.

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Other Wool Producing Countries

Australia, Argentina, New Zealand, Russia, Republic of South Africa, Great Britain, China, and U.S.A.

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The quality of wool is determined by the breeding, Climate, food, general care and health of the sheep.

• Cold weather produced a hard and heavy fiber• Poor or insufficient food retards growth.• It has soft resiliency power and it is also used to make rugs

and blankets.• The chief wool producing countries are Australia, U.S.S.R.,

New Zealand, Argentina, South-Africa and the United States (U.S.A.).

• The chief constituent of wool fiber is a protein substance called ‘Keratin’ and it is the only fiber which contains ‘Sulphur’.

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CLASSIFICATIONS FOR WOOL

• Wool may be classified by two types: 1. Classification by sheep

2. Classification by fleece

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Classification by Sheep:-

There are over 200 grades of wool producing sheep.

– Merino Wool:- Produced from Merino Sheep and the

fibres are very fine, strong and elastic.

– Class two Wools:- Originated in Scotland, Ireland and

Wales.

– Class three Wools:- Originated in the UK, generally are

less elastic and resilient.

– Class four Wools:- Obtained from Mongrel Sheep, are

coarse and hairlike.

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Classification by Fleece (Based on the shearing of the

fleece):-

– Lamb’s Wool: About 6-8 to months.

– Hogget Wool: About 12-14 months.

– Wether Wool: Any fleece clipped after the first shearing of

sheep.

– Pulled Wool: The shearing done by a chemical depilatory

like lime before it is slaughtered for meet.

– Dead Wool: The shearing is done over the dead sheep

– Cotty Wool: The wool obtained from any sheep of severe

weather condition.

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1. CLASSIFICATION BY SHEEP

• 1. CLASS I WOOL (OR) MERINO WOOL

• Merino sheep of Spain produce the best quality wool which is strong, fine elastic and has good working properties.

• It has the greatest amount of crimp of all wool fibers and has a maximum number of scales to give maximum warmth and spinning qualities.

Spain is the only country which produced fine wool known as ‘merino wool’.

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2. CLASS II WOOL

• It is obtained from the sheep from England, Scotland, Ireland and Wales.

• It is 2 to 8 inches in length, has a large number of scales per inch and has good crimp.

• The fibers are strong, fine , elastic and have good working properties.

• It is not as good as merino wool, but nevertheless it is very good quality wool.

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3. CLASS III WOOL

• This class of sheep originated in United Kingdom.

• The fibers are 4 to 8 inches long, are coarser and have fewer scales and less crimp than Merino Wool and

class II wool.

• They are smoother and have more luster.

• They are less elastic and resilient.

• They are nevertheless of good enough quality to be used for clothing.

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4. CLASS IV WOOL

• This class is actually a group of Mongrel sheep sometimes referred to as half-breeds.

• The fibers are 1 to 16 inches long are coarse and hair like, have relatively few scales and little crimp and therefore smoother and more lustrous.

• It has least elasticity and strength and used mainly for carpets, rugs and inexpensive low-grade clothing.

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STRUCTURE OF WOOL

The Cortex of the wool fibre is composed of two distinct sections, Ortho cortex and Para cortex.

The Microscopic structure of wool has following parts:

Cuticle

Macro Fibril

Micro Fibril

Proto Fibril

Wool Polymer

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Structure

• Epicuticle- thin outer membrane covering the cuticle

• Cuticle- protective layer of overlapping flattened cells called scales

• Cortex- major component of wool fiber, inner layer

• Medulla- the central core found primarily in medium and coarse wool

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PHYSICAL PROPOERTIES

• The physical properties of the wool refers to the strength, thermal nature, etc.

• The various physical properties are:

Tenacity

Elastic and Plastic Nature

Hydroscopic Nature

Heat of Wetting

Thermal Properties

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•TENACITYWool is comparatively a weak fiber.

The low Tensile strength of wool is due to the relatively few Hydrogen Bonds that are formed.

When Wool absorbs moisture, the water molecules gradually force enough polymers apart cause a significant no. of hydrogen molecules to break.

Breakage and Hydrolysis of these Inter Polymer forces of attraction are apparent as swelling of fiber and result in further loss of tenacity, when wool is wet.

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• Elastic and Plastic NatureWool has very good Elastic recovery and excellent

Resiliency (ability to withstand elastic force).

This is because of Helical structure of arrangement of monomer or due to the helical polymeric configuration of wool.

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•HYDROSCOPIC NATUREWool is a very Absorbent fiber due to the

Amorphous nature of polymer system. In relatively dry weather, wool develops static electricity. This is because there are not enough water molecules in the polymeric system to dissipate any static electricity which is being developed.

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• HEAT OF WETTINGWool is renowned for its ability to give off small but steady amount of heat while absorbing moisture. This is known as Heat of Wetting.

It is considered to be due to energy given off by the collision between water molecules and the groups in the wool polymer system. This friction is severe and thereby liberates energy.

Thus, wearer feels slightly warm when the wool fabric absorbs moisture.

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• Crimp• Caused by the unique chemical and physical

properties of wool.  The fiber tends to bend and turn in to a resilient 3 dimensional structure.  It holds in air to insulate the wearer. This property make wool naturally elastic and resilient causing rapid wrinkle recovery, durability, bulk, loft, warmth, and resistance to abrasion. 

• Water Absorbency• Wool can absorb up to 30% of its weight in moisture

without feeling damp or clammy.  This makes wool good for all climates since it aids in the body's cooling mechanisms to keep moisture away from the skin.

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• Resistance to Fire• Wool contains moisture in every fiber allowing

it to resist flame without any additional chemical treatment.  The wool will just char and self extinguish.

• Dyeability• Wool absorbs many dyes deeply, uniformly,

and directly without the use of chemicals.  This characteristic allows wool to achieve very beautiful and rich colors when dyed.

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• Durability• The flexibility of wool makes it very durable.  A single

wool fiber can be bent back on itself more than 20,000 times without breaking.  Compare this to the only 3,000 times of cotton and 2,000 times of silk.  Its elasticity makes it very resistant to tearing.  Wool also has an outer film making it resistant to abrasion.

• Resilience• Wool fiber can be stretched up to 50% of its length

when dry and up to 30% of its length when wet without breaking  It will return to its original length when released.

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CHEMICAL PROPERTIES

• EFFECT OF ACIDS AND ALKALISWool is resistant to Acids than to Alkalis because

alkalis hydrolysis the Peptide group( -[CONH]- )

Wool is not at all resistant to alkalis.

Wool, when submerged into high quantity of high concentrations of acids, gets weakened.

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• EFFECT OF BLEACHES Wool is treated with Reducing Bleaches such as

Sodium sulphide Sodium Bisulphide

which converts the color producing component of the fabric to colorless compound.

After this, Oxidizing bleach such as Hydrogen Peroxide is applied which converts compounds into water soluble compounds.

After this, the wool fibre is rinsed off and a permanent bleach is obtained.

The dyes used in wool are : Acid dyes, Mordant dyes, Reactive dyes, etc.

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The hair of the sheep is trimmed first.

The raw wool or newly sheared wool

called grease wool because it contains

the natural oil of the sheep.

Sorting & Grinding:-

– Wool sorting is done by skilled

workers who are experts in

distinguishing by touch and sight.

– Determined by type, length,

fineness, elasticity and strength.

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Garnetting:-

– Separating the used and unused

materials to a fibrous mass by

picking and shredding.

– Fibres are then put into a dilute

solution of Sulphuric Acid to

remove vegetable fibres is called

Carbonizing.

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Scouring:-

– Raw wool is scoured by

washing it in a solution

of soap, warm water

and soda ash or any

other alkali.

– This removes the

grease and oil in wool

and makes it absorbent

to dye.

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Drying:-

– Wool is not allowed to dry

completely, 12-16% of moisture

is left over.

Oiling:-

– Wool is treated with oil to

lubricate it and to keep it from

becoming brittle.

Blending:-

– Wool of different grades may be

blended in this stage.

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Carding:-

– Fibres are passed through rollers covered with

thousands of wire teeth to orient the fibres parallel.

– This separates the woolen yarns and worsted yarns.

Gilling and Combing:-

– The gilling process removes the short staple and

straightens the fibres.

– Combing operation removes the shorter fibres and

places long fibres parallel to each other.

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CARDING PROCESS

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Drawing:-

– Makes the sliver

compact and thin

by doubling and

redoubling the

wool fibre.

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Roving:-– It is a process to hold the thin

slubbers intact.

– The fiber passes between the

rollers, over the coarse wire teeth of

the first card clothing, and over

progressively finer toothed card

clothing.

– the fiber that leaves the machine

are in the form of untwisted ropes

known as ‘ROVINGS’.

WOOL- After ROVING

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Spinning:-

– Roved wool is drawn out and

twisted into yarn.

– Woolen yarns are spun on mule

spinning machine.

– Worsted yarns are spun on any

kind of spinning machines. SPUN WOOL YARNS

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MACHINE SPINNING SPINNING WHEEL

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FINISHES USED

• Fulling

• Crabbing • Decating: It includes two processes

1. Dry Decating

2. Wet Decating

• London shrinking

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Wool Blends

Wool is blended with a wide variety of fibres. Wool and Cotton Wool is blended with cotton in various ratios. The

properties of the yarns and fabrics will be affected by the proportions of the fibres blended. Wool contributes warmth, resilience, abrasion resistance, and drapability. Cotton adds strength and reduces the cost of yarn and fabric. Both fibres are absorbent and can be blended to make a comfortable, durable fabric with a nice hand.

• Wool and Linen Wool is sometimes blended with linen. Linen may be

used in such a blend which is stronger than a pure wool fabric, but is more resilient and drapable than a pure linen fabric.

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GRADES OF WOOL

In order for wool to be sold in International Trade, methods of expressing grades for raw wool have been devised. On the World Market, grade is expressed by a Number System.

The Finer the wool, the Higher the number.

Comparative Grading Systems

• Fine 80s,70s, 64s

• Half-blood 62s, 60s, 58s

• Three-eighths blood 56s

• Quarter-blood 50s, 48s

• Low-quarter blood 46s

• Common 44s

• Braid 40s, 36s

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SOURCES OF WOOL

Large wool producing and exporting nations are:

• Australia ( 50s- 80s)

• New Zealand ( 40s – 60s and carpet grade)

• South Africa ( 60s – 70s and carpet grade)

• Argentina ( 40s – 60s, 64s and carpet grade)

Countries contributing to greatest amount of carpet wool to world market are:

Argentina, India, Pakistan, New Zealand, Syria, Iraq and Iran.

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BENEFITS OF WOOL

• Resists Wrinkles 

• Retains Shape

• Resists Soiling

• Resists Flames     

• Wool is Durable

• Wool is comfortable in all seasons

• Repels Moisture   

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APPLICATIONS OF WOOL

Wool is used in the manufacture of variousProducts like:

• Boots • Carpet • Blankets • Sweaters • Coats • Seat covers • Bed sheets• Cushion covers• Curtains

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MANUFACTURING PROCESS OF WOOL(in detail)

• 1. Preparation

• 2. Sorting and Grading

• 3. Garneting

• 4. Scouring

• 5. Carbonizing

• 6. Drying

• 7. Oiling

• 8. Dyeing

• 9. Blending

• 10.Carding

• 11.Gilling and Combing

• 12.Drawing

• 13.Roving

• 14.Spinning

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1. PREPARATION

• Fleeces vary from 6 to 18 pounds (3-8Kg) in weight and provides 3 lbs (1.5Kg) of scoured wool.

• Wool is sorted and graded according to the quality, then trimmed, rolled up, tied and packed in sacks weighing about 225-350 lbs (100-160Kg).

• Superior wool comes from the sides and shoulders of sheep where it is longer, finer and softer and it is treated as one fleece.

• Wool from the head, chest, belly and shanks is treated as a second fleece.

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• Then wool reaches the mill in bags.

• The raw wool or newly sheared wool is called grease wool as it contains the natural oil of the sheep.

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2. SORTING AND GRADING

• Wool sorting is done by expert skilled workers who distinguish the different qualities by touch and sight.

• Twenty different grades are obtained from one fleece.

• Each grade is determined by type, strength, length, fineness, elasticity and strength.

• The grading system on the world market is based upon the British numbering system which relates the fineness or diameter of wool, etc.

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3. GARNETING

• Recycled wool fibers are obtained by separately reducing the unused and used materials to a fibrous mass by a picking and shredding process called garneting.

• The fibers are then put through a dilute solution of sulphuric acid or hydrochloric acid which destroys any vegetable fiber that may be contained in the raw stock. This process is known as ‘Carbonizing’ and the resultant wool fibers are called “extracts”.

• The new staple ranges from ¼ to 11/2 inch in length.

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4. SCOURING

• “A thorough washing of raw wool in an alkaline solution is called scouring.”

• The scouring machine contains warm water, soap and a mild solution of soda-ash or other alkali and is equipped with automatic rakes which stir the wool.Rollers between the vats squeeze out the water.Valuable by products are obtained from the spent liquors in the scouring of wool.

The most important by product is lanolin which is largely used in manufacture of cosmetics, adhesive plasters, disinfectants, ointments,etc.

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5. CARBONIZING

• Fibers are put in Hydrosulphuric acid or Hydrochloric acid solution to destroy vegetable substance.

•If the wool still contains and vegetable substance after scouring, it is put through carbonizing process which burns out the foreign matter.

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6. DRYING

• Wool is not allowed to become absolutely dry. Usually about 12-16% of the moisture is left in the wool for further handling.

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7. OILING

• Wool becomes unmanageable after scouring, the fiber is usually treated with various oils, including animal, vegetable and mineral or a blend of these to keep it from becoming brittle and to lubricate(oil) it for

the spinning operation.

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8. DYEING

• If wool is to be dyed in the raw stock, it is dyed at this stage whereas wool fabrics are piece-dyed, yarn

skin dyed and some are top-dyed.

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9. BLENDING

• Wool of different grades may be blended or mixed at this stage.

• Inferior grade of wool mixed with better grades of wool or a small amount of cotton is blended with a raw wool and a greater amount of twist is increase the strength in the fabric.

• Manmade fibers such as nylon, polyester or acrylic may be blended with wool and the wool helps in contribution of warmth, absorbency, drape and handling.

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10. CARDING

• The carding process introduces the classification of woolen yarns and worsted yarns.

• At this point, of manufacturing process, it should be decided weather wool fiber is to be made into a woolen or a worsted product, because manufacturing of woolen and worsted is different.

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11. GILLING AND COMBING

• The carded wool which is to be made into worsted yarn is put through gilling and combing operations.

• The gilling process removes the shorter fibers (called as combing noils and of 1-4 inches in length) and places

the longer fibers (tops) as parallel as possible and further cleans the fibers by removing any remaining

loose impurities.

•Combing noils (shorter fibers) are used for ordinary and less expensive fabrics and tops (longer fibers) for manufacturing worsted fabrics as gabardine, whipcord, serge and convert and produce fabrics with good colour, feel and strength,

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12. DRAWING

• It is done only to worsted yarns. It is an advanced operation which doubles and redoubles slivers of wool fibers. The process draws and twists the fibers and makes the slivers more compact and thin.

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13. ROVING

• It is the final stage before spinning. It is a slight twisting operation to hold the thin slubbers (fibers) intact.

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14.SPINNING

• Here the wool roving is drawn out and twisted into yarn.

• Woolen yarns are spun on mule spinning machine. Worsted yarns are spun on mule, ring, cap or flyer kind of spinning.

• Two different systems to spin worsted yarns – is English System and French System:

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Difference between Woolen and Worsted Yarns

WOOLENS

1.Fibers are short (2”length)

2. Woolen yarns are only carded, less twisted and hence weak in strength.

3. Woolen fabrics are woven with plain weave and sometimes twill weave. Weaving is not compact and fabric is not durable or strong.

4.Woolen fabrics are soft, fuzzy, thick and warm but not durable.

5. Woolen can be easily adulterated and napping finish is given to produce soft surface.

6. Less expensive than worsted.

7. -These fibers are more warmer than worsted. -It has no luster and is less durable. -The napped surface tends to catch and hold dirt

but stains can be easily removed.

WORSTED

1. Fibers are long (2-8 inches)

2. Worsted yarns are carded and combed, highly twisted and more strong.

3. Worsted fabrics are woven chiefly with twill weave and weaving construction is close and compact and as such more strong fabric.

4. Worsted fabrics are flat, rough, harsh when worn next to the skin, but more durable.

5. Worsted can not be easily adulterated as it has a hard finish on the surface.

6. More costlier or expensive than woolens.

7. -It wrinkles less than woolen, holds creases and shape, and become shiny with use

-They re amore durable and more resistant to

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SWEATERS

CUSHION COVERS

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CURTAINS

SHAWLS

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BED SHEETS

SOCKS

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CARPETS

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