This document discusses the design and drawing of a tire in AutoCAD. It begins with background on the history and development of tires from early wooden wheels to the invention of the pneumatic tire in 1888. It then reviews tire components and classifications. The main body of the document describes the steps to draw a tire in AutoCAD, including using lines, circles, offsets, fillets, and revolve and polar array commands. It includes diagrams of the tire drawing process and the final rendered tire. In conclusion, the document demonstrates how to create a computer-aided design of a tire in AutoCAD.

1. TYRE
ABDISAMAD MOHAMED AWAYS ID: 31
ABDULLAHI OMAR MOHAMUD ID: 41
IDIRIS MOHAMUD ID: 56
An assignment submitted in full filament of the
Requirements for the machine tool course
Faculty of Engineering
Department of electromechanical
SOMALI NATIONAL UNIVERSITY
DEC 2019

2. PROJECT OF TYRE
Supervised by submitted by
Eng. Ahmed Dayib Abdi Samad Mohamed Aways{ID: 31}
Lecturer Abdullahi Omar Mohamud {ID: 41}
Department of electro-mechanical engineering Idiris Mohamud {ID:56}
Somali national university

3. i
Abstract
A project was undertaken to study the influence of tire design. Tire is a very complex product
from design point of view. The complexity arises because of complex design and embedded
components present in it. The performance demand from a tire is highly complex and confliction
In world there are many recycling process of the used tire. But nowadays the tire’s retreading
process much popular in which old sole can be remove and applying new sole on the old tire. It
is possible up to 2-3 times. This process can maximum utilize of the tire. After this process it
sent to tire recycling process. The retreading process can be subdivided into small process like
treading, vulcanizing, enveloping, buffing. In Enveloping process the envelope is attached and
removes from it. This process held by conventionally or done by labor a years ago the machinery
established by the inventor. The machinery work efficiently but it reduce the life of envelope. So
it would be necessary to redesign the envelope expander new machinery for this enveloping
process

4. ii
List of figures pages
Figure1. 1 vehicle dynamics are primarily influenced by tires .....................................................1
Figure1. 2 early wooden wagons .................................................................................................2
Figure1. 3 various improved wheels ............................................................................................3
Figure 1. 4 cart or wagon wheel ..................................................................................................3
Figure 1. 5 various early solid tires..............................................................................................4
Figure 1. 6 Benz automobile built in 1886...................................................................................4
Figure2. 1 the first gasoline car ............................................................................................6
Figure2. 2 the pioneer of automobile ...........................................................................................6
Figure2. 3 the first front wheel drive automobile .........................................................................7
Figure2. 4 ventus tire...................................................................................................................7
Figure2. 5 enfren tire...................................................................................................................8
Figure2. 6 future tires..................................................................................................................8
Figure2. 7: A cutaway view of a typical radial tire.....................................................................11
Figure3. 1 rectangle drawing .....................................................................................................13
Figure3. 2 using fillet command ................................................................................................13
Figure3. 3 using offset command...............................................................................................13
Figure3. 4 lines, offset, fillet......................................................................................................14
Figure3. 5 using arc command and angle...................................................................................14
Figure3. 6 tire drawing process..................................................................................................14
Figure3. 7: tire drawing process ................................................................................................14
Figure3. 8 using circle and line command .................................................................................15
Figure3. 9 sine wave using trim.................................................................................................15
Figure3. 10 sine wave with offset ..............................................................................................15
Figure3. 11 making tire with revolve command.........................................................................16
Figure3. 12 using polar array.....................................................................................................16
Figure3. 13 tire..........................................................................................................................16

5. iii
Figure3. 14 tire making with AutoCAD.....................................................................................17
Figure3. 15 tire drawing ............................................................................................................17
Figure3. 16 tire drawing of AutoCAD .......................................................................................17

6. iv
List of contents
Contents pages
Abstract....................................................................................................................................................i
List of figures.......................................................................................................................................... ii
List of contents....................................................................................................................................... iv
1. Introduction.....................................................................................................................................1
1.1 Background..............................................................................................................................2
1.2 Creation of the Tire..................................................................................................................2
1.2.1 Beginnings as a Wheel......................................................................................................2
1.2.2 The Beginning of the Tire..................................................................................................3
2. Literature review .............................................................................................................................5
2.1 History of the tire.....................................................................................................................5
2.2 Process of tire ..........................................................................................................................6
I. 1888 The Beginning of Gasoline Cars and the Pneumatic Tire...................................................6
II. 1905 Tread Tire........................................................................................................................6
III. 1920 The Development of Tire Materials..............................................................................6
IV. 1923 Balloon Tire .................................................................................................................7
V. 1940 Tire Structure Development ............................................................................................7
VI. 1947 Tubeless Tire ...............................................................................................................7
VII. 1949 Radial Tire....................................................................................................................7
VIII. 1970 Increased Tire Safety ...................................................................................................7
IX. 1980 Run-Flat Tire................................................................................................................7
X. UHP Tire...................................................................................................................................8
XI. 2000 Tires and the Environment...........................................................................................8
XII. The Future of Tires NPT........................................................................................................8
2.2 TYRE ......................................................................................................................................9
2.3 FUNCTIONS OF A TYRE: .....................................................................................................9
2.4 CLASSIFICATION OF TYRES ............................................................................................10
2.4.1 BASED ON TYRE TREAD...................................................................................................10

7. v
2.5 Tire Components....................................................................................................................11
3. Drawing tire in AutoCAD..............................................................................................................13
3.1. Introduction to AutoCAD............................................................................................................13
3.2. Steps of drawing a tire............................................................................................................13
4. Conclusion ....................................................................................................................................18
5. References.....................................................................................................................................19

8. 1
1. Introduction
Tires are the only contact between a vehicle and the road, transferring actions like steering,
braking, accelerating and tuning to the road surface. Tire is one of the most complex composites
man has ever made. It has many different components with specific roles to play. Tires consist
from the softest solid material to the toughest and the hardest materials like textile fiber and steel
respectively
Tires are critical to driver safety. When in good condition, properly maintained and of the correct
type and size, they enable a vehicle to accelerate, steer and brake safely under a wide variety of
road and weather conditions.
Because they are responsible for much of the vehicle’s handling and stopping ability, tire quality
plays a critical role in the optimal performance of a variety of safety systems, including Antilock
Braking Systems (ABS), Dynamic Stability Control, Active Cruise Control and Forward
Collision Mitigation. Ultimately, the friction between the tires and the road are responsible for
vehicle handling and stopping characteristics [1]
Figure1. 1 vehicle dynamics are primarily influenced by tires

9. 2
1.1 Background
A tire is a strong, flexible rubber casing attached to the rim of a wheel. Tires provide a gripping
surface for traction and serve as a cushion for the wheels of a moving vehicle. Tires are found on
automobiles, trucks, buses, aircraft landing gear, tractors and other farm equipment, industrial
vehicles such as forklifts, and common conveyances such as baby carriages, shopping carts,
wheel chairs, bicycles, and motorcycles.
The primary purpose of the tire is to transmit acceleration and braking torque, generate cornering
forces and provide dampening characteristics [2]. For a common passenger car, the area of all
four tires in contact with the ground is roughly the size of an 8.5 x 11 inch sheet of paper. It is
through this contact patch or footprint that all forces act to move the vehicle according to driver
inputs
1.2 Creation of the Tire
1.2.1 Beginnings as a Wheel
Tires originally began as wheels. The origin of the wheel is unclear, although it is thought to
have been at least 4,000 years ago. The use of the wheel shows that it was at least known that
rolling results in less friction than sliding. Logs or round slices of logs were first used (Fig.1.2).
Gradually, these were replaced by discs made of several planks joined together (Fig. 1.3),
followed by spooked wheels (Fig. 1.4). Wagons were the main means of transportation until
automobiles became popular. These wagons had hubs of evergreen oak or elm, as shown in Fig.
(1.4) these were supported by spokes encircled by a rim or felloe, while an iron band around the
outside to prevent wear from contact with the ground could truly be called a tire.
Figure1. 2 early wooden wagons

10. 3
Figure1. 3various improved wheels
Figure1. 4 cart or wagon wheel
1.2.2 The Beginning of the Tire
The discussion below draws heavily from Taiya no Hanashi [The Story of the Tire] [3]. Vehicles
with iron or wooden wheels were difficult to pull on rough road surfaces. Accordingly, early
tires were the result of various inventors competing to somehow make vehicles travel more
comfortably.
Attempts were made to give tires greater elasticity; what is now known as the solid tire (a tire
made wholly from rubber with no air inside) was invented in 1835 (see figures below).

11. 4
Figure1. 5 various early solid tires
The first automobile with a gasoline engine was built in 1886 by German company Daimler-
Benz. Production of this vehicle started in France in 1890. Although this vehicle had solid rubber
tires, later automobile manufacturers still used metal rings. In 1895, the first pneumatic tire was
developed for such vehicles. A replica of the first Benz vehicle with solid tires is on display at
the Toyota Automobile Museum
Figure1. 6 Benz automobile built in 1886

12. 5
2. Literature review
2.1 History of the tire
The earliest tires were bands of leather [4]. Then iron (later steel) placed on wooden wheels used
on carts and wagons. The tire would be heated in a forge fire, placed over the wheel and
quenched, causing the metal to contract and fit tightly on the wheel. A skilled worker, known as
a wheelwright, carried out this work.
The first patent for what appears to be a standard pneumatic tire appeared in 1847 lodged by the
Scottish inventor Robert William Thomson. However, this never went into production. The first
practical pneumatic tire was made in 1888 on May Street, Belfast, by Scots-born John Boyd
Dunlop, owner of one of Ireland's most prosperous veterinary practices. It was an effort to
prevent the headaches of his 10-year-old son Johnnie, while riding his tricycle on rough
pavements. His doctor, John, later Sir John Fagan, had prescribed cycling as an exercise for the
boy, and was a regular visitor. Fagan participated in designing the first pneumatic tires.
Cyclist Willie Hume demonstrated the supremacy of Dunlop's tires in 1889, winning the tire's
first-ever races in Ireland and then England. In Dunlop's tire patent specification dated 31
October 1888, his interest is only in its use in cycles and light vehicles. In September 1890, he
was made aware of an earlier development but the company kept the information to itself.
In 1892, Dunlop's patent was declared invalid because of prior art by forgotten fellow Scot
Robert William Thomson of London (patents London 1845, France 1846, USA 1847), although
Dunlop is credited with "realizing rubber could withstand the wear and tear of being a tire while
retaining its resilience”. John Boyd Dunlop and Harvey du Cross together worked through the
ensuing considerable difficulties. They employed inventor Charles Kingston Welch and also
acquired other rights and patents which allowed them some limited protection of their Pneumatic
Tire business's position. Pneumatic Tire would become Dunlop Rubber and Dunlop Tires. The
development of this technology hinged on myriad engineering advances, including the
vulcanization of natural rubber using sulfur, as well as by the development of the "clincher" rim
for holding the tire in place laterally on the wheel rim.

13. 6
2.2 Process of tire
I. 1888 The Beginning of Gasoline Cars and the Pneumatic Tire
In 1888, was invented the first gasoline car equipped with unique metal tires covered with rubber
and filled with air, resulting in the pneumatic tire. The public, which was accustomed to hard,
metal tires, believed the pneumatic tire to be no less than revolutionary. Popular use of the
pneumatic tire began in 1895 and it was featured in an automobile race from Paris to Bordeaux.
Figure2. 1 the first gasoline car
II. 1905 Tread Tire
Tread is a part of a tire that comes in direct contact with a road surface. Made out of thick rubber,
tread protects carcass and breaker inside a tire. Road surface friction coefficient increased with a
development of the tread tire and today it is produced in various patterns.
III. 1920 The Development of Tire Materials
Popularization of Automobiles and the Industrialization of Synthetic Rubber
In the late 1913, Henry ford introduced the first conveyor belt assembly line to the world.
In 1931, American company Du Pont successfully industrialized synthetic rubber.
This development allowed tire industry, which had been dependent on natural rubber, to increase
tire quantity and quality ushering in a turning point in tire production
Figure2. 2 the pioneer of automobile

14. 7
IV. 1923 Balloon Tire
Balloon tire, a type of low-pressure tire is used in various types of automobiles to increase its
contact area to road surface with low internal air pressure.
V. 1940 Tire Structure Development
Structural development of automobiles and tires to save fuel In order to relieve a burden of sky-
high oil prices brought on by the oil shock, it became popular to reduce the size and weight of
existing car models. Many manufacturers eventually employed the front-wheel drive method for
their cars. With a development of the tubeless tire in 1903, the resulting weight reduction
contributed significantly to the saving of fuel.
Figure2. 3 the first front wheel drive automobile
VI. 1947 Tubeless Tire
VII. 1949 Radial Tire
Firstly invented in the 1950s, the radial tire refers to a type of tire in which the cords, carcass
plies are vertically arranged to driving direction. Because of lower deformation of radial tire than
bias tire during driving, radial tire has better fuel efficient. Uniform contact of tread in radial tire
to road surface offers good driving stability, especially on high-speed
VIII. 1970 Increased Tire Safety
IX. 1980 Run-Flat Tire
Even with scratches or holes caused due to obstacles or tire abrasion while driving, and the
resulting deflation, the run-flat tire is able to maintain a constant driving speed. It protects the
driver from various accidents that can arise in emergency situations.
Figure2. 4 ventus tire

15. 8
Increased Tire Performance
With the transformation of the automobile from an effective method of transportation into
a symbol of personal financial power and freedom, people became increasingly interested in
driving performance. Driving performance increased with the development of the UHP (Ultra
High Performance) tire, which boasts superior cornering, drivability and braking, in accordance
with new development of tire technology.
X. UHP Tire
The UHP tire is defined as a tire with a rim diameter equal to or greater than 16 inches, an aspect
ratio equal to or less than 55 and speed symbol higher than V (max. speed is 240 km/h). UHP tire
provides superior braking performance and cornering performance at high speed.
XI. 2000 Tires and the Environment
The Development of the Eco Tuning Tire With increasing interest in environmental
conservation, a variety of eco-friendly cars like the hydrogen car and electric car are being
developed. Accordingly, tires that increase fuel saving and thus help protect the environment are
also in development.
Figure2. 5 enfren tire
XII. The Future of Tires NPT
In 2012, Han kook Tire developed an airless tire using a new type of material. The NPT (Non
Pneumatic Tire) saves energy by reducing the production process by half. Created from a new
type of uni-material, it can be reused or recycled. The NPT will be used for eco-friendly car
models including hydrogen, electric and hybrid cars.
Figure2. 6 future tires

16. 9
2.2 TYRE
Tire is a circular and ring like part of a vehicle which comes in contact with ground. Tyres are
fitted on rims and are filled with compressed air. Since their invention, natural rubber is the most
widely used material in manufacturing of tyres. However, modern tyres also employ materials
like synthetic rubber, fabric, steel wires, carbon black and some more compounds. Tyres find
place in wide range of locomotives, from bicycles to aero planes.
• Pneumatic tyre is a flexible, toroidal, compressed gas (normally air) container mechanically
attached to the outer circumference of rim of a vehicle wheel. The name is derived from “Attire”
– a protecting covering or coat.
• The rubber exterior of a pneumatic tyre is merely a flesh for a skeleton of fabric; this skeleton
and the manner in which it is constructed are of fundamental importance in establishing the
tyre’s characteristics.
• A tyre is an integral component of a vehicle and is the intermediary between the vehicle and the
road.
2.3 FUNCTIONS OF A TYRE:
Supporting the vehicle weight including payload (load carrying capacity)
• Transferring Traction and Braking forces to the road surface (Traction, Torque and braking)
• Absorbing Rod shocks (Cushioning and Enveloping)
• Changing and maintaining Direction of travel (Steering response and stability during
cornering)
• Low Rolling Resistance
• Minimum Noise / Road Vibration
• High Speed safe operation Capability
• Aesthetics & Comfort

17. 10
2.4 CLASSIFICATION OF TYRES:
In general, there are two major classes of tyres, according to the presence or absence of tubes in
them. Thus, they are called tubed tyres' and 'tubeless tyres' respectively. Furthermore, based on
the construction or skeleton of tyres known as carcass, tyres are classified into the following
main types:
i. Cross ply or bias ply: In these tyres, ply cords are at an angle of 30°-40° to the tire axis.
ii. Radial ply: In these tyres, ply cords run in the radial direction.
iii. Belted-bias ply: This is a combination of the above-mentioned types.
However, majority of the tyres used nowadays belong to the class of radial tubeless tyres.
2.4.1 BASED ON TYRE TREAD
I) Standard/ All Season Tyre
Your car was probably driven out of the factory on all season tyres. It is an average tyre that is
suitable for all year round use. It works equally well in the wet and the dry.
The tread block pattern is designed not to be noisy when used on standard roads but enables
adequate water dispersion to provide grip in wet conditions.
The rubber used is a harder compound to extend the tyre's life. This can comprise on handling
and cornering but for the majority of drivers it is not noticeable.
II) Performance Tyre
Also known as summer tyres, performance tyres are designed for provide excellent grip in the
dry. Often used on fast cars or for a driver whose style requires increased handling performance.
They can be used all year round if you live in a region with a warm climate and little rain.
A soft rubber compound is used which decreases the lifespan of the tyre but provides enhanced
grip. It is important that the car tyres are kept in excellent condition. Driving in the wet is hard
enough with these tyres but if there is any sign of wear it is virtually impossible to get good grip.
III) Winter Tyre
Winter car tyres are designed to cope with the poor weather and difficult driving conditions that
the winter season brings. They can handle snow and ice. Winter tyres can have small metal studs
embedded into the tread for extra grip in extreme conditions.

18. 11
The tread block pattern on winter car tyres is larger and more pronounced than on standard tyres.
This improves grip but also increases the tyres' operating noise.
These tyres cannot be used all year round because in dry conditions they wear out extremely
quickly and damage the road surface.
IV) All Terrain Tyre
All terrain tyres provide good grip on loose surfaces such as dirt and sand. Often used by off
road vehicles, they can be used on standard roads but are very noisy.
Like the winter tyre the tread block pattern is large to improve grip. The tyre's sidewalls are
stiffer to cope with uneven surfaces and unexpected potholes.
Mud tyres are an extreme type of all terrain tyres, designed to be used in mud and dirt. They
have very large tread block patterns that are only suitable for driving on that type of terrain.
V) Run Flat Tyres
Run flat tyres are a relatively new concept but are now becoming more common on new cars.
They are designed to minimise the loss of handling that occurs after a puncture.
The car tyre can operate without air to enable the vehicle to continue to be driven. However this
is only suitable for a short distance and at a reduced speed, until the tyre can be safely changed.
For further advice consult a car tyre specialist who will provide you with impartial advice on the
best tyres for your vehicle.
2.5 Tire Components
From the outside, tires appear to be simply constructed. However, today’s tires are made up of
many raw materials comprising a multitude of parts, all carefully engineered and assembled to
provide safety, durability and specific performance characteristics [5].
The accompanying picture shows a cross-section view of a modern radial tire. Following are
short descriptions of the main components in Figure 2 keyed to the numbers in the illustration
Figure2. 7: A cutaway view of a typical radial tire

19. 12
I. Grooves – circumferential slots that channel water away from under the tread to help prevent
hydroplaning on wet roads.
II. Ribs – circumferential bands of raised tread rubber, situated between the grooves that provide
the tire’s contact patch with the road.
III. Tread Pattern – the design of the tread area that contacts the road
IV. Shoulder – the transitional area between the tire tread and sidewall that helps maintain
traction while cornering. LT-rated tires have additional reinforcement in this area for greater
durability.
V. Belts – rubber-coated layers of special fabric made up of parallel cords woven from high-
strength materials wrapped around the tire carcass to make the tread more rigid. The belt
increases puncture resistance and reduces tread squirm that improves fuel economy, minimizes
heat buildup and extends tire life.
VI. Under tread – the lower section of a tire’s tread, made with heat-resistant rubber compounds
that increase durability and, in some cases, help improve fuel economy.
VII. Inner liner – a special thin halo butyl-rubber layer inside the tire that prevents air leakage
through the carcass. This liner replaces the inner tubes used on older tires.
VIII. Plies – layers of special fabric made up of parallel cords coated with rubber and are strong
in one direction yet flexible in others. Plies extend from bead to bead to provide structural
strength around the tire’s interior air chamber. Early tire plies were made with cotton cord.
Modern designs use high strength synthetic fibers such as rayon, nylon, polyester, fiberglass and
Kevlar that better resist stretching and damage from impacts. Heavy-duty truck tires sometimes
use plies made with steel cord for maximum strength and load-carrying ability.
IX. Bead cable – a strong woven wire cable that the plies wrap around where the tire mounts to
the wheel. The cable prevents the bead from deforming and helps secure the tire in place on the
rim.
X. Bead apex/filler – a hard rubber piece that extends from the bead cable into the lower sidewall
to control flexibility for better handling. On run-flat tires, the bead apex/filler is a larger and even
stiffer piece that supports the sidewall when driving with the tire deflated.
XI. Bead chafer – a layer of fabric that helps protect the bead cable and apex/filler from being
chafed by the wheel rim or damaged when the tire is mounted on a wheel.

20. 13
3. Drawing tire in AutoCAD
3.1. Introduction to AutoCAD
The term CAD (Computer Aided Design) applies to a wide range of programs that allow the user
to create drawings, plans, and designs machines. AutoCAD is one such program and it main
claim to fame is that it is relatively easy to use, it is very comprehensive in its ability to create
2D and some 3D drawings, and it is very popular. Seventy percent of the CAD users in the
world use AutoCAD
3.2. Steps of drawing a tire
I. Step 1: Start AutoCAD and draw a rectangle with base and height 5,3 respectively
Figure3. 1 rectangle drawing
II. Step2: Make fillet(1.85) at the two upward vertex use the command explode to explode the
hole section Delete the downward lines then your drawing should became like this one
Figure3. 2 using fillet command
III. Step3: Use poly line, arc, and second point and give line with its distance of 3cm then Make
it mirror and join the remaining and then make offset of 0.5cm
Figure3. 3 using offset command
IV. Step4: Make the lines which is been dimensioned as shown in the figure

21. 14
Figure3. 4 lines, offset, fillet
V. Step5: Make 3 point arc the three positions make offset 0.4cm and join them by line 80° then
erase unnecessary lines
Figure3. 5 using arc command and angle
VI. Step6: Move the x-axis line 6cm downward Use revolve command. Then select object to
revolve and then chick both ends of the line
Figure3. 6 tire drawing process
And then make it SW isometric and shaded then Isolate the selected part and hide it
Figure3. 7: tire drawing process

22. 15
VII. Step7: Make view control top view and also make the visualize style 2d wire frame
Then make line 4.65cm the make circle with radius 0.3cm as shown in the figure
Figure3. 8 using circle and line command
VIII. Step8: Then use trim to erase unsecure semicircles to look like sine wave
Figure3. 9 sine wave using trim
IX. Step9: In this step use the offset of 0.2cm Connect the two parts by a line Then use scale
command till your sine wave will have same length as the line
Figure3. 10 sine wave with offset
X. Step10: Move the sine wave part by holding center of the line make extrude the sine wave
part as shown in the figure

23. 16
Figure3. 11 making tire with revolve command
XI. Step11: Chick polar array command the select sine wave part the select axis of rotation the
chick both ends of the line then make the numbers 80
Figure3. 12 using polar array
XII. step12: use solid subtract your drawing should be like figure
Figure3. 13 tire
XIII. Step13: make a thin rectangle to top view and divide into two parts then make them extrude

24. 17
Figure3. 14 tire making with AutoCAD
XIV. step14: use solid subtract to cut the object then replace the hidden object choosing isolate
and end of object, so the tire drawing finished
Figure3. 15 tire drawing
XV. Step14: select all object then click control1 and change the color choose a black color
Figure3. 16 tire drawing of AutoCAD

25. 18
4. Conclusion
For years tyres have been running on pneumatic tyres and there was almost a full stop for any
further improvement of tyres.
In 20 𝑡ℎ
century the engineers have come up with a new concept where the tyres never require
air, if the drawbacks that are been encountered presently are and improved then there is good
future for these tyres .and can run without the necessary of air.

26. 19
5. References
1. AAA all season tire testing: newsroom.AAA.com
2. D. Beach and J. Schroeder, an Overview of Tire Technology, Rubber World, 2000.
3. Hattori, Rokuro: Taiya no Hanashi [The Story of the Tyre], Taiseisha, June 1992, p. 34.
Jidōsha-yō Taiya no g [Studies on Automobile Tyres], Yokohama Rubber Company ed.,
Sankaido, 15 April 1995, p. 7, etc.
4. ^ Bertman, Stephen (2005). P.35 Handbook to Life in Ancient Mesopotamia Check |url=
value (help). Oxford University Press. Retrieved 2 August 2014.
5. B. Lindemuth, "An Overview of Tire Technology," in the Pneumatic Tire, U.S
Department of Transportation, 2006, pp. 6-10.