15. Materials Science

verdeagendaΗλεκτρονική - Συσκευές

21 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

71 εμφανίσεις

1.

Brown Dwarf
s

A brown dwarf

is a
celestial

body that has never quite beco
me a star. A typical brown dwarf

has a mass that is 8 percent or less than that of th
e Sun. The mass of a brown dwarf

is too small to
generate the internal temperatures capable of igniting the nuclear
burning

of hydrogen to release
energy and light.


A brown dwarf
contracts at a steady rate, and after it has contracted as much as possible, a
process that takes about 1 m
illion years, it begins to cool off. Its emission of light diminishes with the
decrease in its internal temperature, and after a period of 2 to 3 billion years, its emission of light is so
weak that it can be difficult to observe from Earth.


Because of th
ese
characteristics of a brown dwarf
, it can be easily distinguished from stars in
different st
ages of formation. A brown dwarf

is quite

distinctive because its surface temperature is
relatively cool and because its internal composition
-
approximately 75 pe
rcent hydrogen
-

has
remained
essentially the same as it was when first formed.
A white dwarf
, in contrast, has gone though a long
period when it burns hydrogen, followed by another long period in which it burns the
helium created
by the burning of

hydrogen

and ends up with a core that consists mostly of oxygen and carbon with a
thin layer of hydrogen surrounding the core.


It is not always

as easy, how
ever, to distinguish brown dwarf
s from large planets. Though
planets are not forme
d in the same way as brow
n dwarf
s, they may in their current have some of the
same characteristics as a
brown dwarf
. The planet Jupiter, for example, is the largest planet in our
solar system with a mass 317 times that of our planet and resembles a brown in that it radiates energy
based on its internal energy.
It is the mechanism by which the
y were formed that distingu
ishes a high
-
mass planet such as Jup
iter from a low
-
mass brown dwarf
.

2.

Pulsars

There is still much for astronomers to learn about pulsars. Based on what is known, tha
t

term
pulsar is used to describe the phenomenon of short, precisely timed radio bursts tha
t are emitted from
somewhere in space. Though all is not known about pulsars, they are now believed in reality to
emanate from spinning neutron stars, highly reduced cores of collapsed
attars

that are theorized to
exist.


Pulsars were discovered in 1967, w
hen Jocelyn Bell, a graduate student at Cambridge
University, noticed an unusual pattern on a chart from a radio telescope. What made this pattern
unusual was that, unlike
other radio signals from celest
ial objects, this series of pulses had a highly
regul
ar period of 1.33730119 seconds. Because day after day the pulses came from the same place
among the stars, Cambridge researchers came to the conclusion that they could not have come from a
local
source

such as an Earth satellite.


As more and more were fo
und, astronomers
engaged in debates over thei
r nature. It was
determined that a pulsar could not be a star in as much as a

normal star is too big to pulse so fast. The
question was also raised as to whether a pulsar might be a white dwarf star, a dying sta
r that has
collapsed to approximately the size of the Earth and is slowly cooling off. However, this idea was so
rejected because the fastest pulsar known at the time pulsed around thirty ti
mes per second and a white
dwarf
, which is the smallest known type

of star, would not hold together if it were to spin that fast.


The final conclusion among astronomers was that only a neutron star, which is theorized to be
the remaining core of a collapsed star that has been reduced to a highly dense radius of only aro
und 10
kilometers, was small enough to be a pulsar. Further evidence
of the link between pulsars and neutron
stars was found in 1968, when a pulsar was found in the middle of the Crab Nebula. The Crab Nebula
is what remains of the supernova of the year 105
4, and in as much as it has been theorized that neutron
stars some
times remain following supernova

explosions, it is believed that the pulsar coming
f
rom the
Crab Nebula is evidently just such a neutron star.

3.

Limestone

Limestone caves can be spectacular st
ructures filled with giant stalactites and stalagmites.
These caves

are for
med when rainwater, which is a weak acid, dissolves calcite, or lime, out of
limestone. Over time, the lime
-
laden water drips down into cracks, enlarging them into caves.



Stalact
ites’
, which grow down from cave ceiling, are formed in limestone
caves when
groundwater containing dissolved lime drips from the roof of the cave and leaves a thin
deposit

as it
evaporates.
Stalactites generally grow only a fraction of an inch each year, but over time a
considerable number may grow to be
s
everal yards long.
In cases where the supply of water is
seasonal, they may actually have growth rings resembling those on tree trunks that

indicate how old
the stalactites are.


Stalagmites are formed on the floor of a limestone cave where water containing dissolved lime
has dripped either from the cave ceiling or from a stalactite above. They develop in the same way as
stalactites, when wat
er containing dissolved limestone evaporates.
In some limestone caves with
mature limestone devel
opment, stalactites and stalagmites grow together, creat
ing limestone pillars
that stret
ch from the cave
floor to the cave ceiling.

4.

Smart Energy

The next few d
ecades will see great changes in the way energy is supplied and used.


In some
major oil producing nations, peak oil has already been reached, and there are increasing fears of global
warming.


Consequently, many countries are focusing on the switch to a l
ow carbon economy. This
transition will lead to major changes in the supply and use of electricity.

Firstly, there will be an
increase in overall demand, as consumers switch from oil and gas to electricity to power their homes
and vehicles.

Secondly, there

will be an increase in power generation, not only in terms of how much
is generated, but also how it is generated, as there is growing electricity generation from renewable
sources. To meet these challenges, countries are investing in Smart Grid technolog
y.


This system
aims to provide the electricity industry with a better understanding of power generation and demand,
and to use this information to create a more efficient power network.

Smart Grid technology basically involves the application of a compute
r system to the
electricity network.


The computer system can be used to collect information about supply and demand
and improve
engineers

ability to manage the system.


With better information about electricity
demand, the network will be able to increase the amount of electricity delivered per unit generated,
leading to potential reductions in fuel needs and carbon emissions.

Moreover, th
e computer system
will assist in reducing operational and maintenance costs.

Smart Grid technology offers benefits to the consumer too.


They will be able to collect real
-
time information on their energy use for each appliance.


Varying tariffs throughout
the day will give
customers the incentive to use appliances at times when supply greatly exceeds demand, leading to
great reductions in bills.


For example, they may use their washing machines at night.


Smart meters
can also be connected to the internet o
r telephone system, allowing customers to switch appliances on
or off remotely.


Furthermore, if houses are fitted with the apparatus to generate their own power,
appliances can be set to run directly from the on
-
site power source, and any excess can be so
ld to the
grid.

5.
Plate Tectonics

According to the theory of plate tectonics, the upper portion of the Earth’s lithosphere, which
contains the heavier oceanic and the
lighter continental crusts, consists of rigid plates that are in
constant motion. This
theory provides a cohesive model to explain the integrated actions of c
ontinental
drift, seafloor sprea
ding, and mountain formation.

The Earth’s plates are estimated to have an average depth of approximately 60 mile (or 100
kilometers), but they are believ
ed to vary considerably in size.
Some are estimated
to be continental or
even hemispheric in size, while other are believed to be much smaller.
Though the actual boundaries
and sizes and shapes of the plates are not known for
sure, it has been postulated t
hat there are six
major plates and somewhere around
the same number of smaller ones. Most of the plates consist of
both
sail

(continental) and sima (oceanic) crust.
They are in contrast movement, though they move
at
an extremely slow pace, and these
movements cause frequent interactions between plates.

At this time, scientists have identified three different types of boundaries between plates. At a
divergent

boundary, plates are moving away from each other. This type of boundary occurs at an
oceanic r
idge, where new material is being added to the seafloor from deeper within the Earth.
Shallow earthquakes and underwater volcanoes are associated with this type of plate activity.
At a

convergent

bound
a
ry, plates are moving toward each other and collide, c
ausing vast folding and
crumpling along the edges of the plates.
In addition to the folding and crumpling, one of the plates
slowly folds under the other.

The bound
a
ries between convergent plates are generally found around
the edges of ocean basins and are
sometimes
associated
with deep ocean trenches.

A third type of
bound
a
ry is a
transcurrent

bound
a
ry, which involves two plates sliding past each other laterally,
wit
hout the folding and crumpling that occurs at a convergent bound
a
ry. This type of bound
a
ry is
thought to be far less common
than the other two types of bound
a
ries.





6.

Solar system

Our solar system consists of an average star we call the
Sun
, the planets
Mercury
,
Venus
,
E
arth
,
Mars
,
Jupiter
,
Saturn
,
Uranus
,
Neptune
, and
Pluto
. It includes: the satellites of the planets;
numerous
comet
s
,
asteroids
, and meteoroids; and the interplanetary medium. The Sun is the richest
source of electromagnetic energy (mostly in the form of heat and light) in the solar system. The Sun's
nearest kn
own stellar neighbor is a red dwarf star called Proxima Centauri, at a distance of 4.3
light
years

away. The whole solar system, together with the local stars visible on a clear night,
orbits the
center of our home galaxy, a spiral disk of 200 billion stars we call the
Milky Way
. The Milky Way
has two small galaxies orbiting it nearby, which are visible from the southe
rn hemisphere. They are
called the Large Magellanic Cloud and the Small Magellanic Cloud. The nearest large galaxy is the
Andromeda Galaxy
. It is a spiral galaxy like the Milky Way b
ut is 4 times as massive and is 2 million
light years away. Our galaxy, one of billions of galaxies known, is traveling through intergalactic
space.




The planets, most of the satellites of the planets and the asteroids revolve around the Sun in the
same direction, in nearly circular orbits. When looking down from above the Sun's north pole
, the
planets orbit in a counter
-
clockwise direction. The planets orbit the Sun in or near the same plane,
called the
ecliptic
. Pluto is a special case in that its orbit is the most high
ly inclined (18 degrees) and
the most highly elliptical of all the planets. Because of this, for part of its orbit, Pluto is closer to the
Sun than is
Neptune
. The axis of rotation for most of the p
lanets is nearly perpendicular to the ecliptic.
The exceptions are
Uranus

and
Pluto
, which are tipped on their sides.


7.
Geothermal Heating


Our dependence on fossil fuels is a huge problem. Fossil fuels emit pollutants into the air. And
they are non
-
renewable. That means that once you use them, they can’t be restored. That is, we can’t
create any more. Finally, like all scarce resources, they
are expensive. So we have the incentive to find
other energy sources.


One option comes from the Earth. Under the surface of the Earth, there is a natural source of
heat. We can extract this heat and use it in our homes. We do this by putting a heat pump d
eep in the
Earth. It pumps heat from the Earth into our homes in the winter. The energy is clean and it never runs
out.


Unfortunately, you cannot get enough heat from the Earth to maintain a comfortable
temperature in your home. You still have to use anot
her source, such as electricity. However, if you
use geothermal as your principal heating source, your second source of energy will not be exerted as
much. This will bring down your heating costs during the winter months. Though geothermal heating
systems
are expensive to install, they save money in the long run.

8.

Carbon Footprints


Humans are doing a lot of damage to the Earth. Our lifestyles rely on certain technologies. And
many of these technologies require power. The sources of that power emit greenh
ouse gases. Theses
gases pollute the air. Polluting the air has serious implications. For one thing, it is not healthy to
breathe polluted air. In addition, greenhouse gases cause the Earth’s temperature to rise. This causes
changes in the climate. Climate

change is responsible for extreme weather like floods, droughts, and
storms.


Sometimes the problem seems overwhelming. Individuals wonder what they can do. One way
to grasp the subject is through the idea of a carbon footprint. This is the amount of gree
nhouse gases
we are each responsible for. So, instead of feeling overwhelmed by the enormity of the problem, we
can do something. We can reduce our carbon footprint.


How can we change our lifestyles to minimize our carbon footprints? First, we can assess
our
current level of consumption. Then, we can explore ways to reduce it. If we have to drive, we can set a
limit to how much we drive. Then, we may not exceed this limit. But what if we do exceed it?


The other positive thing we can do is offset our carbo
n footprint. This means doing positive
things for the Earth to counter the negative things we do. For example, we can plant trees. Trees filter
the air and also serve as an energy source.

9.


E
-
books


These days it seems that everything is going digital.
Books are no exception. The e
-
book was
designed to take the place of the printed book. It is a hand
-
held device. Text appears on a screen, just
like a computer.


There are several advantages to the e
-
book. For one thing, it takes up less space. E
-
books are

capable of storing hundreds of books. Therefore, readers will no longer need bookshelves to store all
of their books.


Another distinction between the e book and normal books is that it is like a computer. Users
can search for certain words in a book, or
links to other texts can be included. This can make research
less time consuming.


Readers with difficulty reading will note another important difference between books and their
digital media equivalent. They can change the text size to make it easier to r
ead. Further, a text

to
-
speech version of the software can be added so that they can listen instead of reading.


From the publisher’s point of view, distribution is made easier. Books are easy to replicate.
The need for paper and ink is eliminated. And b
ooks don’t have to be shipped as they can be sent
electronically.

10.

Eco
-
friendly Computers


Computers are now part of our everyday lives. And they keep getting better. As they do, many
people upgrade. That is, when a better product comes out, they get fi
d of their old one and replace it.
The problem with this trend is that it creates a lot of waste. Corporate interests demand that consumers
continually update their systems. This often results in a lot of waste. The solution is biodegradable
computers.


I
n many ways computers can be seen as eco
-
friendly. They cut down on the amount of paper
we need to use. That means we cut down less trees. Information can be shipped electronically. We
don’t have to transport it by air, land, or sea. The amount of power it

takes to run a computer is
marginal. But the machines are made from toxic materials. They are not recyclable and they take up
room in landfills.


A company called Micro

Pro began working on a solution in 1992. It has since developed an
eco
-
friendly comput
er. Items such as keyboards and monitors are made of wood and other
biodegradable materials. That means








11.

Wireless

Wi
-
Fi is a type of technology. It creates networks. These networks are wireless. Computers can
communicate with one another withou
t the use of wires. Internet connections can be made without
wires. People can make phone calls over the internet. The telephone wires are not used. Such items as
TVs and DVD players can be connected to networks using Wi
-
Fi technology. Wi
-
Fi technologies w
ere
introduced in 1997. Since then several versions have come out. Each one is an improvement on the
previous one.



How is this possible? Wireless devices have to be capable of making a connection. They would
all have to use the same technology. If one co
mpany uses one type of technology, another must use its
equivalent. That’s the only way they can connect to the same network. So, different companies must
work together to set standards. That way their different devices can work on the same network. The
Wi
-
Fi Alliance sets these standards.


Wi
-
Fi is now common in corporate environments. People working in different locations can
communicate easily. Distribution of tasks is simpler. People can work faster. There are fewer problems
caused by delays. And the m
ore access points, the more efficient the whole network is.


Hot spots are starting to appear in more places. These are areas where Wi
-
Fi is available for
free. Anyone who happens to be in the area can use it. They just have to have a Wi
-
Fi certified devi
ce.
These hot spots might be might be at a café, a hotel, an airport, or even an entire city. Some cities
provide free wireless internet access.


Another good thing about Wi
-
Fi is cost. It gets rid of the need for cables. These can be costly
to install. T
he cost of installing a wireless local area network is marginal in comparison. Wi
-
Fi also
makes it easier to expand existing networks.


Wi
-
Fi technology has changed the way we do business. It has also changed the way we live our
lives. The internet is more

accessible than ever. And we can easily network our computers with others.
The internet is now part of our everyday lives.

12.
The Kyoto Protocol

The countries of the world often argue about environmental issues. Some are very vocal about
global war
ming because they think it is very dangerous. They think that countries like the US use too
many fossil fuels such as oil. Using too much of these fuels hurts the environment and causes global
warming.



Global warming is changing our weather. There are m
ore floods and storms in many places.
Often, many people are killed in floods. For years, scientists have warned us that we have to use less
fuel.


There have been successive meetings between leaders to figure put what to do. One of the most
important conf
erences took place in Japan in 1997. It was held in the city of Kyoto. Leaders from
many countries assembled in a meeting room there to talk about what to do. They talked a lot and then
some of them agreed to try to halt global warming. They signed a docum
ent called “The Kyoto
Protocol”.


Some countries did not want to stop using fossil fuels and their leaders did not sign at Kyoto.
They thought scientists were lying and making things sound more serious than they are. Some
countries that sell oil to the res
t of the world did not want to sign. They were scared their countries
would become poor if people used less oil. Leaders who signed believe we can find new forms of
energy. They pay scientists to find out what we can do. Many scientists believe we can use
the Sun to
make energy. We can also use wind or water.

13.

What is Electricity?

Electricity is a form of energy. Electricity is the flow of electrons. All matter is made up of
atoms, and an atom has a center, called a nucleus. The nucleus contains positively charged particles
called protons and uncharged particles called neutrons. The

nucleus of an atom is surrounded by
negatively charged particles called electrons. The negative charge of an electron is equal to the
positive charge of a proton, and the number of electrons in an atom is usually equal to the number of
protons. When the b
alancing force between protons and electrons is upset by an outside force, an atom
may gain or lose an electron. When electrons are "lost" from an atom, the free movement of these
electrons constitutes an electric current.



Electricity is a basic part of

nature and it is one of our most widely used forms of energy. We
get electricity, which is a secondary energy source, from the conversion of other sources of energy,
like coal, natural gas, oil, nuclear power and other natural sources, which are called pr
imary sources.

How is electricity generated?

An electric generator is a device for converting mechanical
energy into electrical energy. The process is based on the relationship between magnetism and
electricity. When a wire or any other electrically condu
ctive material moves across a magnetic field,
an electric current occurs in the wire. The large generators used by the electric utility industry have a
stationary conductor. A magnet attached to the end of a rotating shaft is positioned inside a stationary

conducting ring that is wrapped with a long, continuous piece of wire. When the magnet rotates, it
induces a small electric current in each section of wire as it passes. Each section of wire constitutes a
small, separate electric conductor. All the small
currents of individual sections add up to one current of
considerable size. This current is what is used for electric power.


14.

Alternative resources of energy



Natural Gas
, in addition to being burned to heat water for steam, can also be burne
d to produce
hot combustion gases that pass directly through a turbine, spinning the blades of the turbine to
generate electricity. Gas turbines are commonly used when electricity utility usage is in high demand.


Petroleum
can also be used to make
steam to turn a turbine. Residual fuel oil, a product refined
from crude oil, is often the petroleum product used in electric plants that use petroleum to make steam.

Nuclear power

is a method in which steam is produced by heating water through a process
c
alled nuclear fission. In a nuclear power plant, a reactor contains a core of nuclear fuel, primarily
enriched uranium. When atoms of uranium fuel are hit by neutrons they fission (split), releasing heat
and more neutrons. Under controlled conditions, thes
e other neutrons can strike more uranium atoms,
splitting more atoms, and so on. Thereby, continuous fission can take place, forming a chain reaction
releasing heat. The heat is used to turn water into steam, that, in turn, spins a turbine that generates
e
lectricity.


Hydropower, the source for 9% of U.S. electricity generation, is a process in which flowing water
is us
ed to spin a turbine connected to a generator. There are two basic types of hydroelectric systems
that produce electricity. In the f
irst system, flowing water accumulates in reservoirs created by the use
of dams. The water falls through a pipe called a penstock and applies pressure against the turbine
blades to drive the generator to produce electricity. In the second system, called ru
n
-
of
-
river, the force
of the river current (rather than falling water) applies pressure to the turbine blades to produce
electricity.

15.
Materials Science

Every day we come into contact with many thousands of manufactured objects that are
essential to modern life: the vehicles that we travel in; the clothes that we wear; the machines in our
homes and offices; the sport and leisure equipment we use; the compu
ters and phones that we can’t
live without; and the medical technology that keeps us alive. Everything we see and use is made
from materials derived from the earth: metals, polymers, ceramics, semiconductors and composites.

To develop the new products and technologies that will make our lives safer, more convenient,
more enjoyable and more sustainable we must understand how to make best use of the materials we
already have, and how to develop new materials that will meet the
demands of the future. Materials
Science and Engineering involves the study of the structure, properties and
behavior

of all materials,
the development of processes to manufacture useful products from them, and research into recycling
and environmentally f
riendly disposal.

The basic building block of all matter is the atom and there are 94 different types that occur
naturally on earth. These are ‘the elements’ and include hydrogen, oxygen, carbon, silicon, iron,
copper, and
aluminum
. All materials are made
up of these atomic building blocks but differ in their
microstructure: the types of atom they contain, the pattern in which the atoms are arranged and the
way in which the atoms are joined together. The central concept in Materials Science and Engineering
is that the properties and
behavior

of every material is
dependent

on its microstructure, and that
microstructure can be controlled by the way in which the material is made and processed. Materials
Scientists test the mechanical, physical, chemical and el
ectrical properties of materials and explore
how these properties depend on the microstructures they engineer and observe using high powered
microscopes.





16.

Telecommunication

Telecommunications service providers and equipment vendors today face signi
ficant
challenges as they address the multitude of changes and competitive challenges sweeping their
industry. Networks are increasing in size and complexity as demand pressures grow and as new
technologies


from wireless communications and fiber optics t
o multimedia, computers and
advanced Internet technologies converge upon the network. As the competitive environment
intensifies, it becomes increasingly important for service providers and equipment vendors to be able
to react to changes quickly and effec
tively while maintaining the highest levels of performance and
reliability.

One of the most important means of achieving these goals is the ability to efficiently model,
manage, and optimize the next generation of telecommunications equipment and services.

Telecommunications networks are among the most demanding environments in terms of performance
and reliability, and as a result place enormous demands on the database management systems that are
at the heart of most telecommunications equipment and service
s.


The next generation of telecommunications applications requires a new generation of
database technology
-

technology that draws on the strengths of prior generation DBMS technology
and blends them with the latest software advances; a DBMS designed fro
m the ground up for the
highest performance and reliability in concurrent, highly distributed, multiplatform environments with
extremely large data storage requirements. The Versant ODBMS (object database management
system) is such a product. Versant is a
seventh generation DBMS combining the direct modeling of
complex, graph/structured data with the power of today’s leading object programming languages
combined with report oriented query capabilities. As a result, the Versant ODBMS allows
telecommunication
s service providers and equipment vendors to solve problems that they have been
unable to solve using older storage technologies.

17.


Computer language

A computer language is the means by which instructions and data are transmitted to computers.
Put
another way, computer languages are the interface between a computer and a human being. There
are various computer languages, each with differing complexities. For example, the information that is
understandable to a computer is expressed as zeros and ones

(i.e., binary language). However, binary
language is incomprehensible to humans. Computer scientists find it far more efficient to
communicate with computers in a higher level language.

Block
-
structured language

Block
-
structured language grew out of resea
rch leading to the
development of structured programming. Structured programming is based on the idea that any
computer program can be written using only three arrangements of the information. The arrangements
are called sequential, selection, and iteratio
n. In a sequential arrangement, each programming
instruction (statement) is executed one after the other. This order is vital. The execution of the second
statement is dependent on the prior execution of the first statement.

PASCAL, ALGOL, and MODULA
-
2 ar
e examples of block
-
structured languages. Examples
of non
-
block structured languages are BASIC, FORTRAN, and LISP. Refinements of BASIC and
FORTRAN produced more structured languages.

Block
-
structured languages rely on modular construction. A module is a r
elated set of commands.
Each module in a block
-
structured language typically begins with a "BEGIN" statement and ends with
an "END" statement.




18.

Nineteenth Century Photography

___The nineteenth century saw
enormous advances in photography in the US. Photos from this time
period can tell us about history. But they don’t just tell us about the subject of the photo. We can learn
about the art of photography.

___We can infer the date of a photo by the style. The

daguerreotype, for example, was the earliest
style in common use. A silver
-
plated, mirror
-
like metal sheet was used. It was placed in a camera and
exposed to the image. The final image was sharp and full of detail.

___The ambrotype was used from 1854 to t
he early 1860s. It became popular because it was cheaper
than the daguerreotype. It used a glass plate to expose the image in the camera. Another glass plate
was then attached to protect it. Then the thing was interested into a metal frame.

___The ambrotyp
e preceded the tintype. The tintype used a thin, black, metal plate instead of glass. It
was invented in 1856. It was popular until the early 1900s.
The

photos didn’t have to be cased like
ambrotypes. This was because they weren’t so fragile.

___These are

just a few of the many techniques used in photography in America in the nineteenth
century.


19.

Visual Arts


Visual arts are arts that appeal to our sense of sight. As such, the possibilities for visual arts are
endless. Paintings, drawings, fil
m and sculptures are just a few examples. There has been some
disagreement as to what should be included in the visual arts. Namely, should crafts be seen as such?
There was a time when only fine arts could be included in the visual arts. Craftsmen were no
t thought
to be artists. This era preceded the Arts and Crafts Movement which was founded in the early
twentieth century. This movement helped create an appreciation for craftsmanship. Today, crafts too
are considered visual arts.


Our ideas of wha
t constitutes art are always changing. ■ A modern example is graffiti. ■ Graffiti
is seen by some as vandalism. ■ They think it is ugly. ■ But others see it as art. For one thing, it can be
very beautiful. For another, it can make a strong statement about
society.


The visual arts are old as humanity. Some of the earliest examples of visual arts are cave
paintings. These were made by early humans. They would often depict scenarios such as hunting.
Such paintings not only tell us about the daily live
s of these early humans, but they tell us something
about their psyches. In other words, we can see what their lives were like, but we can infer something
about the way their minds worked. For example, some cave paintings indicate that the artists held
rel
igious beliefs.


A good visual artist does more than depict an image. He or she attaches meaning to that image.
The hope is that it will invoke a certain emotional response in the viewer. The range of possible
responses, of course, is enormous. Aga
in, the work can tell us much about the subject. But it can tell
us even more about the artist.


There is a great diversity in the types of visual art available. And the possibilities are growing.
New technologies allow for new genres. Computer gr
aphics, for example, has opened up a world of
possibilities to artists. And the quality gets better and better as technology improves.


20.


Life Science

___Life Science is the study of all living things. It is the study of animals, humans,
and plants. It is
also the study of tiny living things that can only be seen with a microscope. We call these small


things micro
-
organisms.

___Life Science is also sometimes called biology. This word comes from two Greek words: ‘bio’,
meaning ‘life’ and
‘logos’, meaning ‘to speak of’. Many scientific words come from Greek. This is
because the ancient Greeks were some of the first people to try and understand nature. They wrote
their ideas down and today we can still read them.

___Aristotle, a Greek philo
sopher, who lived from 384 BCE until 322 BCE, is known as the ‘father of
biology’. He was one of the very first people to make highly accurate studies of animals and plants.

___Aristotle had a lot of perseverance. He knew that he had to study the same anim
al or plant for a
long time to get to know it. He studied living things carefully. He also did many experiments. He
wrote down everything he saw.

___Aristotle believed that all
scientists

had to be rigorous and that they could not guess. That is also
why h
e did not confine his studies to one place. He traveled a lot. Today, life scientists still use many
of his methods.

21.

Evolution


In 1859, a man called Charles Darwin wrote a famous but controversial book. The book was
called
On the Origin of Species
. It was about something called ‘evolution’. This was a very exciting
idea about how animals and plants changed over millions of years.


Darwin had traveled all over the world. He had studied many different plants and animals. He
could see how they

all adapted to their environments. He saw that animals that lived in deserts did not
use a lot of water. He saw that animals that lived in the snow had thick fur to keep them warm. He
decided that it took a long time for animals and plants to change like
this. He thought it took thousands
of years for them to change just a title.


Darwin believed that people had also changed over time. He wrote that people and monkeys had
come from the same animal. He had a colleague called Thomas Huxley who also t
hought so. They
upset many people. The idea was incompatible with the Bible. The Bible said that God had made
people.


The church tried to prohibit students from learning about evolution. They thought Darwin’s ideas
were evil. There was a lot of ev
idence to show that Darwin was right and his ideas could not be
ignored.


Darwin also saw how weaker animals often died while stronger animals didn’t. This meant that
only the strongest and smartest animals would have babies. Darwin thought this wa
s nature’s way of
making sure that there would only be strong animals on Earth.



22
.
Effective Management and the Employee Interview

___The manager’s job is to make sure the business is running well. A big part of the business is the
workers. They have to be doing their best for the business to be doing its best. So managers have to
make sure workers are doing their best. To do this they have to be good leaders.

___Good leaders should understand why some people work hard and some don’t
. ■ Then they can
provide motivation for workers. ■ Money is not the only motivation for workers. ■ Workers want to
know that they are appreciated. They want to feel like they are part of the company’s success. ■

___ Managers need to enhance worker
-
manage
r relations. One way is to do brief interviews every
three months. This allows managers to compile information. Workers can express their attitudes
toward certain policies. Then they feel like they are being listened to. This makes them likely to be
more c
ooperative.

____■ It is important that workers know the purpose of the interview. If they think it is an evaluation
they will perform differently.
■ The fear of termination can a
ffect their level of honesty. ■ They
should see the interview as a chance to e
xpress themselves. ■ Then it will be more productive.


23.


Market Economy


Competition is the most important thing in a market economy. Firms compete with one another
for business. This helps to keep prices reasonable. To get some insight into how th
is works, think of
what would happen if firms cooperated. The motivation of every firm is to enhance their profit
margins. One way to do this is to increase price. If all of the firms were cooperating, they could set any
price. The consumer would have to p
ay it or do without the commodity being sold.


In general, firms don’t cooperate. They compete. Consider this example. A pencil costs twenty
-
five cents to make. Firm A makes pencils and sells them for two dollars. Firm B sells them for one
dollar.
Firm B’s pencils are just as good as Firm A’s. Which firm will make more money? Well, if
they sold an equal number of pencils, Firm A would. But they won’t sell an equal number of pencils.
Firm B will sell more. This is because consumers will look for the
best price. So, Firm B will sell more
pencils and earn a greater profit. So, in general, the firm that offers the best product for the best price
should turn the best profit. Increasing price will not enhance profit margins unless the competition
does the
same.


There are situations in a market economy where no competition exists. This is called a
monopoly. When a firm has no competition, it has a monopoly. ■ It can virtually set any price because
consume
rs have only one option. ■ The
other option i
s to do without the commodity. So the firm
needs to compile data on the maximum amount consumers are willing to pay for their product. Then
they can charge that price. Generally, though, if a firm has a monopoly, it won’t last. ■ The opening of
new firms t
o compete with them will coincide with their initial success. ■ A steep inclination in the
demand curve for a certain product will signal other suppliers to provide it. Furthermore, there are
laws in place that keep firms from maintaining a monopoly in any

industry.



24.


Mining Process

In addition to the various types of deep mining, several types of surface mining may be used
when minerals lie relatively close to the surface of the earth. One type is open
-
pit mining. The first
step is to remove the overbur
den, the layers of rock and dirt lying above the ore with giant scrapers.
The ore is broken up in a series of blasting operations. Power shovels pick up the pieces and load them
into trucks or, in some cases, ore trains. These carry it up ramps to ground l
evel. Soft ores are removed
by drilling screws, called augers.


Another type is called placer mining. Sometimes heavy metals such as gold are found in soil
deposited by streams and rivers. The soil is picked up by a power shovel and transferred to

a long
trough. Water is run through the soil in the trough. This carries soil particles away with it. The metal
particles are heavier than the soil particles and sink to the bottom, where they can be recovered.


The finishing
-
off process of minin
g is called mineral concentration. In this process, the desired
substances are removed from the waste in various ways. One technique is to bubble air through a
liquid in which ore particles are suspended. Chemicals are added that make the minerals cling to

the
air bubbles. The bubbles rise to the surface with the mineral particles attached, and they can be
skimmed off and saved.

25.

Sericulture or Silk P
roduction


Sericulture, or silk production, has a long and colorful history unknown to most people.
Archaeological finds show that sericulture dates to at least 2
500 B.C
., and may be much older. For
much that time, China kept the secret of silk to itself as one of the most zealously guarded secrets in
history. Anyone revealing the secret of silkworm cul
ture or trying to smuggle silkworm eggs out of
China was punished by death.


The key to China’s domination of silk production lies with one species native to China: the
blind, flightless moth Bombyx mori
. This insect lays five hundred or more eggs in four or five days
and dies soon after. The eggs are like pinpoints
-

one hundred of them weigh only one gram. From one
ounce (28.3 grams) of eggs come about 30.000 worms (the larvae of the moth), which eat a t
on of
white mulberry leaves and produce twelve pounds (5.4 kilograms) of raw silk. The silkworm of
Bombyx mori produces smoother, finer, and rounder thread than other silkworms. Over thousands of
years, this Chinese moth has evolved into the specialized si
lk producer that it is today.


At one time, silk was reserved exclusively for the use of the Chinese emperor. Gradually, all
classes of society began wearing silk. In addition to being used for clothing and decoration, silk came
to have industrial uses in

China. T
his is something that happened
in the West only in modern times.
Silk was used for musical instruments, fishing lines, bowstrings, bonds of all kinds, and even for
manufacturing paper. During the Han Dynasty, silk became an absolute value in itsel
f. Farmers paid
taxes in both grain and silk. Values were calculated in lengths of silk as they had once been calculated
in gold. The importance of silk is even reflected in all the dialects of the Chinese language. For
example, of the 5.000 most common ch
aracters in the Mandarin alphabet, around 250 have silk as their
key.


In spite of their secrecy, the Chinese eventually lost their monopoly on silk production.
Sericulture reached Korea around 200 B
.
C
. w
hen immigrants from China arrived there. Sericultur
e
came to India in A.D.550 wh
en sericulture came to the West. S
ilkworms were carried by travelers in
hollow tubes of bamboo to Constantinople. This allowed a silk industry to be established the Middle
East and later Italy. However, high


quality Chinese s
ilks still had a market in the West.


26.

What is a business leader?


What is a business leader? Is it the same as a manager? There is certainly an overlap between
these two roles, but as the busi
ness author Bernard bass wrote,

Some managers do not lead, and

some
leaders do not manage.”

There are some personality traits and behaviors that are characteristic of a
leader, and some that are characteristic of a manager. For example, leaders are committed to
innovation and tend to look to the future for threats an
d opportunities. Managers try to maintain the
status quo and concern themselves with solving problems in the present.


Leadership and management are both important to a business organization. Once an
organization is established, managers go about maintaini
ng the system, assuming that the organization
will always be the same. Management keeps the organization going. However, the environment in
which an organization operates is always in flux. There are changes in consumer tastes, technology,
cultures trends,

and historic events. If the organization is entirely in the management mode, it may not
spot these trends because managers tend to look
in
w
ard.

However, if the organization is in the
leadership mode, it will track these changes and shape the organization
to face new challenges and
keep the organization relevant.


Here’s a classic example: In the 1950’s and 60’s, North American auto makers built large,
heavy, powerful cars with gas
-
GUZZLING engines because that was what consumers wanted. The oil
crisis of t
he early 1970’s however, shifted consumer attitudes towards lighter, smaller cars with more
fuel
-
efficient engines. Being in manag
ement mode, the “Big Three”

t
he three major North American
auto makers

were very slow to recognize this trend and continued to

manufacture the kind of cars
that they had made for years. Meanwhile, European and especially Japanese automakers had been
making economical cars for years. During this period, The Big Three lost a great deal of market sha
re
to international automakers.

27
. Computer Games

Computer games were designed and played as long ago as the 1950’s. The first known game
was Tennis for Two (1958), designed by William Higginbotham. Another early game was Steve
Russell’s Space

war! (1961).These games never became very p
opular. It wa
s not until the 1970’s and
80’s
,when computer arcade games were introduced, that computer games attracted millions of game
-
players. The first to make splash was Pong (Atari, 1972).It was designed by Nolan Bushnell and Alan
Alcorn. The game pla
y was extremely

simple. Two players bounced a
moving ball
back

and forth
between their two electronic paddles. Bushnell placed the first game machine in local gas station.
When he returned in a few days, the machine was so full of coins that it could no lo
nger operate. Pong
became an instant success and it helped create the arcade game industry. Other blockbuster game such
as Space Invaders

(bally/Midway 1978),

Asteroids (Atari, 1979),

and Donkey Kong (Nintendo,

1981)

followed. Perhaps the most popular arca
de game ever, Pac Man (Bally /Midway, 1980) was based on
an ancient Japanese folk tale. Some these arcade games, and other games that were not seen in
arcades, were available for play on personal computers. It can even be said that computer games
helped po
pularize the idea of owning a home computer and shaped the way computers were made.
Steve

jobs and Steve Woznaik (Who has

met while designing games foe Atari) designed the Apple II.
The first popular personal computer, so that it could be used to play comp
uter games at home

Today there are four main types of devices that computer game can be played on. Personal
computers consoles handheld consoles, and arcade machines are all common platforms. Personal
Computer (PC) games are designed to be played on standa
rd home computers. Often no special
controls are needed
-
the game can be played with a keyboard or mouse
-
but some games are played
with a joy stick. Video feedback is received by the user thought the computer monitor and audio
feedback through speakers or h
eadphones.
Players can buy PC

games at the store
-
usually stored on
CD ROMs
-
or download them from the internet. Players of PC game can also play against live
opponents on the Internet.

28.

Thomas Edison’s Invitation


At the end of the 1800’s, Thomas Edison introduced the incandescent light bulb and changed
the world. Remarkably, the incandescent bulb used today has changed little in over a hundred years.
An incandescent light consists of a glass bulb filled with an ine
rt gas such as argon. Inside the bulb,
electricity passes
through

a metal filament. Because of resistance, the filament becomes so hot that it
glows. Given that 20% of the world’s electricity is used to power lights, this represents an enormous
amount of w
asted energy.


In the 1940’s a new, more efficient form of lighting, the fluorescent bulb, was introduced.
Fluorescent work by passing electrical current through gas in a tube, producing invisible ultraviolet to
visible light. A phosphor coating on the ins
ide of the tube then converts the ultraviolet to visible light.
Little heat is wasted. Fluorescents have proved popular in offices, factories, and stores, but
they

never
took over the residential lighting market. The harsh color isn’t as pleasing as the wa
rmer glow of
incandescent lamps. Besides, they have a tendency to flicker on and off and to produce an annoying
buzz.


Now, lighting engineers are developing a new form of lighting that is both pleasing to the eyes
and energy efficient. This is the light
-

emitting diode, or LED. LEDs are made up of layers of electron
-

charged substances. When an electrical current passes through the layers, electrons jump from one
layer to another and give off light without producing heat. Different types of materials resul
t in light of
different colors. Red, green, and orange LEDs have been used for decades in devices such as digital
clocks, calculators, and electronic toys. In the future, however, white
-

light
-

emitting diodes (WLEDs)
may be used to light homes. Engineers
say that they are significantly more efficient than either
incandescent or fluorescent lights.


Arrays of colored LEDs are beginning to be used in traffic lights and automotive lights. Today,
colored light through
a colored plastic filter. This
is incredi
bly inefficient because only the red light
that passes

through the filter is used. The rest is wasted. Because LEDs actually produce red light, no
filter is needed and no light is wasted. LEDs have other practical applications as well. For example,
they ca
n be used to light heat
-

sensitive materials like food or important documents.


2
9
.

Modern Architecture

The dissatisfaction with such a general situation at the turn of the twentieth century gave rise to
many new lines of thought that served as precurso
rs to Modern Architecture. Notable among these is
the Deutscher Werkbund, formed in 1907 to produce better quality machine made objects. The rise of
the profession of industrial design is usually placed here.

Following this lead, the Bauhaus school, founde
d in Germany in 1919, consciously rejected history
and looked at architecture as a synthesis of art, craft, and technology.

When Modern architecture was first practiced, it was an avant
-
garde movement with moral,
philosophical, and aesthetic underpinnings.

Immediately after World War I, pioneering modernist
architects sought to develop a completely new style appropriate for a new post
-
war social and
economic order, focused on meeting the needs of the middle and working classes. They rejected the
architectur
al practice of the academic refinement of historical styles which served the rapidly declining
aristocratic order.

The approach of the Modernist architects was to reduce buildings to pure forms, removing
historical references and ornament in favor of funct
ionalist details. Buildings that displayed their
construction and structure, exposing steel beams and concrete surfaces instead of hiding them behind
traditional forms, were seen as beautiful in their own right. Architects such as Mies van der Rohe
worked
to create beauty based on the inherent qualities of building materials and modern construction
techniques, trading traditional historic forms for simplified geometric forms, celebrating the new
means and methods made possible by the Industrial Revolution.

Many architects resisted Modernism, finding it devoid of the decorative richness of
ornamented styles. As the founders of the International Style lost influence in the late 1970s,
Postmodernism developed as a reaction against the austerity of Modernism. Ro
bert Venturi's
contention that a "decorated shed" (an ordinary building which is functionally designed inside and
embellished on the outside) was better than a "duck" (a building in which the whole form and its
function are tied together) gives an idea of
this approach.

30
.

Urban Design

Early human settlements were essentially rural. As surplus of production began to occur, rural
societies transformed into urban ones and cities began to evolve, such as that of Katal Huyuk in
Anatolia and Mohenjo Daro

in India. In many ancient civilizations, such as that of the Egyptians' and
Mesopotamians', architecture and urbanism reflected the constant engagement with the divine and the
supernatural, while in other ancient cultures such as Persia architecture and u
rban planning was used
to exemplify the power of the state.

The architecture and urbanism of the Classical civilizations such as the Greek and the Roman
evolved from civic ideals rather than religious or empirical ones and new building types emerged.
Archi
tectural styles developed.

Cities in traditional societies were mostly very small by modern standards. Babylon, for
example, one of the largest ancient cities of the Middle East, extended over an area only 3.2 square
miles


and probably at its height. The

world’s first cities appeared in about 3,500BC, in the river
valleys of the Nile in Egypt, the Tigris
-
Euphrates in what is now Iraq, and the Indus in what is today
Pakistan. Rome under
Emperor

Augustus was easily the largest ancient city outside China, ha
ving
some 300,000 inhabitants.

Streets in cities serve many purposes besides carrying vehicles, and city sidewalks
-
the
pedestrian parts of the streets


serve many purposes besides carrying pedestrians. Streets and their
sidewalks, the main public spaces
of a city, are its most vital organs. Think of a city and what comes to
mind? Its streets. If a city’ streets look interesting, the city looks interesting; if they look dull, the city
looks dull. More than that, and here we get down to the first problem, i
f a city’s streets are safe from
barbarism and fear, the city is thereby tolerably safe from barbarism and fear. When people say that a
city, or a part of it, is dangerous or is a jungle, what they mean primarily is that they do not feel safe
on the sidewa
lks.


Urban design concerns the arrangement, appearance and functionality of towns and cities, and
in particular the shaping and uses of urban public space. It has traditionally been regarded as a
disciplinary subset of urban planning, landscape architect
ure, or architecture. However, with its
increasing prominence in the activities of these disciplines, it is better conceptualized as a design
practice that operates at the intersection of all three, and requires a good understanding of a range of
others be
sides, such as urban economics, political economy and social theory.