martes, 13 de enero de 2015

FABRIC MATERIALS

foto
Adam Knits
N
atural fibres are greatly elongated substances produced by plants and animals that can be spun into filaments, thread or rope. Woven, knitted, matted or bonded, they form fabrics that are essential to society.
Like agriculture, textiles have been a fundamental part of human life since the dawn of civilization. 
While the methods used to make fabrics have changed greatly since then, their functions have changed very little: today, most natural fibres are still used to make clothing and containers and to insulate, soften and decorate our living spaces. Increasingly, however, traditional textiles are being used for industrial purposes as well as in components of composite materials, in medical implants, and geo- and agro-textiles.

Plant fibres

Plant fibres include seed hairs, such as cotton; stem (or bast) fibres, such as flax and hemp;leaf fibres, such as sisal; and husk fibres, such as coconut.

Animal fibres

Animal fibres include wool, 
hair and secretions,
 such as silk.

lunes, 12 de enero de 2015

PLASTIC. CLASSIFICATION


There are two main types of plastics and these are named Thermoplastics and Thermosetting Plastics.

Thermoplastics are made up of lines of molecules with few cross linkages. This allows them to soften when heated and to be bent into a variety of shapes and forms. They become stiff and solid again when cold. This process can be repeated many times. The bond between the molecules is weak and become weaker when reheated, allowing reshaping. Thermoplastics tend to be composed of 'long chain monomers. They can be recycled.


Thermosetting Plastics are made up of lines of molecules which are heavily cross linked. It creates a rigid molecular structure. They may be heated the first time and shaped but they become permanently stiff and solid. They cannot be reshaped again. The molecules of these plastics are cross linked in three dimensions and this is why they cannot be reshaped or recycled


domingo, 11 de enero de 2015

PLASTICS

                                    DEFINITION OF PLASTIC

Plastics are man-made materials. Plastics have taken the place of traditional materials like woods and metals.

Plastics differ from other materials largely because of the size of their molecules. Most materials have molecules made up of less than 300 atoms, plastics contain thousands of atoms. We call them Macromolecules.

Some plastics are derived from natural substances such as animals, insects and plants but most are man-made. These are named Synthetic Plastics.
The first plastic based on a synthetic polymer was made from phenol and formaldehyde, with the first viable and cheap synthesis methods invented by Leo Hendrik Baekeland in 1909, the product being known as Bakelite.
Most synthetic plastics come from crude oil but coal and natural gas is also used. 

Monomers are chemical substances consisting of a single molecule. Thousands of these are linked together in a process called Polymerisation to form new compounds called Polymers. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics. The vast majority of plastics are composed of polymers of carbon and hydrogen alone or with oxygen, nitrogen, chlorine or sulfur.

viernes, 9 de enero de 2015

STONE AND CERAMIC MATERIALS

STONE: marble, granite, slate.
STONE BINDERS: plaster, cement, mortar, concrete.
CERAMICS: Baked clay, earthenware, heat resistant material, stoneware, porcelain.
GLASS
            - Shaping techniques: mould blowing, float glass making and lamination

jueves, 8 de enero de 2015

FABRIC MATERIALS

Fabric materials can be natural or synthetic:

Natural:
- Vegetable origin: cotton, linen, hemp.
- Animal origin: wool, silk.
- Mineral origin: asbestos, metals.

Synthetic:
Nylon, polyester, rayon.

lunes, 15 de diciembre de 2014

UNIT 3. MATERIALS. VOCABULARY




A
Ash
Aluminium
Ash
B
Birch
B eech
Branch
Bark
Broadleaf
Bronze
C
Chesnut
Copper
Cotton
Cork
D
Deciduous tree
E
Elm
Evergreen tree

F
Fir
G
Growth  rings
Gold
Glass
H
Heartwood
Hardwood
I
Iron
L
Leaf
Leaves
Leather
M
Metal
N
Needle
O
Oak
P
Pine
Poplar
Petroleum
Plastic
R
Roots 
Rubber
S
Stem
Seed
Steel
Sapwood
Softwood
Sap
Silver
Stone
Silk
T
Timber
Tree
Trunk
W
Wood
Wooden
Walnut
Wool






viernes, 12 de diciembre de 2014

PROPERTIES OF MATERIALS

PROPERTIES OF MATERIALS

STRENGTH
The ability of a material to stand up to forces being applied without it bending,
 breaking, shattering or deforming in any way.

ELASTICITY
The ability of a material to absorb force and flex in different directions,
 returning to its original position.

PLASTICITY
The ability of a material to be change in shape permanently. 

DUCTILITY
The ability of a material to change shape (deform) usually by
 stretching along its length.

TENSILE STRENGTH
The ability of a material to stretch without breaking or snapping.

MALLEABILITY
The ability of a material to be reshaped in all directions without cracking

TOUGHNESS
A characteristic of a material that does not break or shatter when receiving
a blow or under a sudden shock.

HARDNESS
The ability of a material to resist scratching, wear and tear and indentation.

CONDUCTIVITY
The ability of a material to conduct electricity.

miércoles, 10 de diciembre de 2014

KINDS OF MEMORY IN COMPUTER

In computingmemory refers to the physical devices used to store programs  or data  on a temporary or permanent basis for use in a computer or other digital electronic device.

TYPES:

- RAM (RANDOM ACCESS MEMORY): Volatile memory is computer memory that requires power to maintain the stored information.
- ROM (READ ONLY MEMORY): Non-volatile memory is computer memory that can retain the stored information even when not powered. New contents can not be added. Used to store the instruction of routine type, permanent in nature and used to control or supervise the hardware.

martes, 9 de diciembre de 2014

COMPUTER´S VOCABULARY

1. Address
14.Dot
27.Memory
40.Spam
2.Address book
Download
Menu
Toolbar
3. Addressee
Email
Message
USB
4.Attach
Email Address
Network
User name
5.Backup
Erase, Delete
Password
Virus
6.Bandwidth
File
Print
Web page
7.Browser
Folder
Program
Website
8.Button
Home page
Save
Window
9.Click
Icon
Screensaver
48.Wireless
10.Cursor
Install
Search engine

11. Cut and paste
Key
Slash

12. Data
Keyword
Server

13.Desktop
26.Link
39.Software


1. TRANSLATE  INTO SPANISH

jueves, 4 de diciembre de 2014

THE BINARY NUMBERING SYSTEM

Computers use binary code. This is based on the binary numbering system that uses the digits 0 and 1 to represent any character or number. The value of these digits depends on their position in the group. In the binary code the value is determined by a base-2 system.

To convert a binary number into a decimal number:

1. Find the successive powers of 2, starting with 2^0, followed by 2^1, 2^2, etc.
2. Multiply by either the 1 or 0  the relation to that position.

To convert a decimal number into a binary number:

1. Divide the decimal number by 2 successively until the quotient is 1.
2. Put the remainders of the quotient in order from right to left.