NUCLEAR POWER PLANT

NUCLEAR POWER PLANT

A nuclear power plant (NPP) is a thermal power station in which the heat source is one or more nuclear reactors.

The schematic arrangement of a nuclear power station is shown above.
The whole arrangement can be divided into following main stages.
(i)Nuclear Reactor (ii)Heat Exchanger (iii)Steam Turbine (iv)Alternator
(i)Nuclear Reactor
It is an apparatus in which nuclear fuel(U235)is subjected to nuclear fission.It controls the chain reaction that starts once the fusion is done.If the chain reaction is not controlled,the result will be an explosion due to the fast increase in the energy released.
A nuclear reactor is a cylindrical stout pressure vessel and houses fuel rods of Uranium moderator and control rods.The fuel rods constitute the fission materials and release huge amount of energy when bombarded with slow moving neutrons.The moderator consists of graphite rods which enclose the fuel rods.The control rods are of Cadmium and and are inserted in the reactor.Cadmium is strong neutron absorber and thus regulates the supply of neutrons for fission.When the control rods are pushed in deep enough,they absorb most of fission neutrons and hence few are available for chain reaction, which therefore stops.However,hence they are being withdrawn,more and more of these fission neutorns cause fission and hence the intensity of chain reaction is increased.Therefore by pulling out the control rods,power of nuclear reactor is increased,whereas by pushing them in,it is reduced.In actual practice,the lowering or raising of control rods is accomplished automatically acoording to the requiremen t of load.The heat produced by the reactor is removed by the coolant, generally a sodium metal.The coolant carries heat to the heat exchanger.
(ii)Heat Exchanger
The coolant gives up the heat to the heat exchanger which is utilised in raising the steam.After giving up heat,the coolant is again fed to the reactor.
(iii)Steam Turbine
The stean produced in the heat exchanger is led to the steam turbine througha valve.after doing a useful work in the turbine,the steam is exhausted to the condenser.The condenser condense the steam which is fed to the heat exchangerthrough feed water pump.
(iv)Alternator
The steam turbine drives the alternator which converts mechanical energy into electrical energy.The output from the alernator is delivered to the bus bars through tansformers,circuit brakers and isolators.

A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction.

Nice words of Pamaran (http://pamaran.wordpress.com) to think about Nature's present condition.

Nice words of Pamaran (http://pamaran.wordpress.com) to think about Nature's present condition.

The following lines are a part of Mr.Pamaran's one of the articles - "IRUPATHAAM NOOTTRAANDIN ISAI NANDHAN RAASAIYAAVUKKU". Really...... touching..... We need to think and do something in this regard.

"நகரத்தின் நகங்கள் நீண்டு……
வயல்வெளிகள் ரியல் எஸ்டேட்டுகளாய்…….
மிச்சமிருக்கிற மரங்களும் சூறையாடப்பட்டு…….உயர் ரகக் குழந்தைகளுக்கான டிஸ்னி லேண்டுகளாய்…….
கிராமத்துச் சிறுவர்கள் வெட்டுக்கிளியும்,பொன்வண்டும் பிடித்துத் திரிந்த புதர்க் காடுகள்….ஹாலிடே ரிசார்ட்டுகளாய்….
எங்கள் இயற்கை ‘நவீனத்தின்’ கோரப்பற்களால்குதறப்பட ஆரம்பித்தாயிற்று."

Air Pollution

Air Pollution

(wikipedia, www.solcomhouse.com/airpollution.htm)

Pollution (is a process) is defined as the excessive discharge of undesirable substances into the environment, adversely altering the natural qualityof the environment and causing damage to humans, plants and animals.

Air pollution is the introduction of (undesirable or unwanted substances) chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere.

A substance in the air that can cause harm to humans and the environment is known as an air pollutant.

Classification of Pollutants

1. primary

2. secondary.

Primary pollutants are directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.

Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone — one of the many secondary pollutants that make up photochemical smog.

Some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.

Examples for Primary Pollutants are :

Sulfur oxides

Nitrogen oxides

Carbon monoxide

Carbon dioxide

Volatile organic compounds (VOC)

Particulate matter

Persistent free radicals

Toxic metals, such as lead, cadmium and copper.
Chlorofluorocarbons (CFCs)

Ammonia (NH3)

Odors — such as from garbage, sewage, and industrial processes
Radioactive pollutants

Examples for Secondary Pollutants are :

Particulate matter formed from gaseous primary pollutants and compounds in

photochemical smog

Ground level ozone (O3) formed from NOx and VOCs

Also Read the following link for "Air Pollution" - Indian Scinario :

http://envfor.nic.in/soer/2001/ind_air.pdf

Ecology and it's components

Ecology and it's components

(Courtesy:http://thelivingenvironmentcheatsheet.blogspot.com/2010_04_01_archive.html)

What is ecology?Ecology is the scientific study of how living things interact with the environment

Autotrophs are producers and producers are organisms that make their own food. They are the only organisms that can convert solar energy into chemical energy or food (organic compound). They carry out autotrophic nutrition. Plants and algae are autotrophs.
Auto: means self
Troph: means feeder
Autotrophs are self-feeders
PLANTS ARE AUTOTROPHS. (They make their own food)
ALGAE ARE AUTOTROPHS (They make their own food)Scientists estimated that about 65 - 85% of the oxygen we breathe comes from algae.

Heterotrophs are consumers and consumers are organisms that eat or obtain nutrients made by autotrophs. They depend on autotrophs for food. Horses, cows, lions and humans are heterotrophs.

Herbivores are heterotrophs that eat plants only, EX. COWS .
Carnivores are heterotrophs that eat meat only, ex. lions.
Omnivores are heterotrophs that eat both meat and plants, ex. humans.
Decomposers are organisms that break down dead organisms and return them to the soil. They recycle nutrients. Ex. of decomposers are fungi and bacteria.
Predators are organism that kill other organisms for food, ex. a lion is a predator.

Prey are organisms that are killed and eaten by other organism, ex. deers are killed and eaten by lions.

Scavengers are heterotrophs that eat dead organisms, Ex. vultures.

Biotic are living things.
Abiotic are nonliving.Niche is the role that the organism play in the environment. For example, a lion's role is "predator"Habitat is the place where organisms live.Carrying Capacity refers to the maximum number of organism a habitat can support. Once the number of organisms reaches the carrying capacity, it levels out or stop growing.
Limiting Factors refers to any biotic or abiotic aspect of the environment that affect population growth. For example, in a desert, water and temperature are abiotic limiting factors; food, prey, and predator are biotic factors that can affect population growth.

Species Two organisms are of the same species if the can reproduce (make babies or offspring) and their babies are fertile. That is their babies can also make babies.

Population: Organisms of the same species living at the same place at the same time, for example a population of dogs, a population of cats.

Community: Different populations living at the same place and at the same time. For example, we live in a community made up of people, cats, dogs, trees, other animals and plants.
Ecosystem consist of the living and the nonliving

The Food Chain And The Food Web show how energy moves through the ecosystem.

EXAMPLE OF FOOD CHAIN

Energy for this food web comes from the sun.

THINK! The arrow in the food chain or the food web represents energy. The caterpillar is receiving its energy from the flowers by eating them.
What happens to the owl population if the snake population is removed from the food chain?
How is the caterpillar population affected by the removal of the snake population?

EXAMPLE OF FOOD WEB

How is the rabbit population affected if the deer population is removed from the food web?

The first organism in the food chain or the food web is always a plant because only plants can convert sunlight into food.
In the next level in the food chain or web are the herbivores because herbivores eat plants.
Carnivores are found on the third level or higher because they eat herbivores or other carnivores.
The arrow in the food chain or food web represents energy
Energy decreases as it goes through the ecosystem because energy is used for life functions and energy is lost as heat.
- If you remove an organism from the environment, the environment becomes less stable.
- The greater the biodiversity, the more stable the environment.

Questions
Why are plants at the bottom of the food pyramid?
What happens to energy as it goes through the ecosystem?
In the food web, how come no arrow is pointed toward the plant?
What is the role of decomposers?
Identify two organisms that carry out decomposition.
What does the arrow represent in the food web?
At what level of the energy pyramid would you find the largest amount of biomass?

Answers
Plants are at the bottom of the food pyramid because they can convert sunlight into food for animals.
The decomposers recycle nutrients, or break down dead organisms and return them into the soil so that they can be used by plants.
Fungi and bacteria carry out decomposition
In the food web, the arrow represents energy.
The largest amount of biomass is found at the bottom of the energy pyramid.

Ecological Succession

ECOLOGICAL SUCCESSION

Courtesy:wikipedia
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed.

Succession may be initiated either by formation of new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form of disturbance (e.g. fire, severe windthrow, logging) of an existing community. Succession that begins in areas where no soil is initially present is called primary succession, whereas succession that begins in areas where soil is already present is called secondary succession - is the invasion of a habitat by plants on land that was previously vegetated. Removal of past vegetation may be caused by natural or human disturbances such as fire, logging, cultivation, or hurricanes.

Succession stops when species composition changes no longer occur with time, and this community is said to be a climax community.

Courtesy:http://geopolicraticus.wordpress.com/2010/04/30/ecological-succession-in-cultural-geography/

courtesy:http://mrswolfgang.wikispaces.com/Spack-Weber+Ecological+Succession

Ministers of Environment and Forests Ministry - India & Tamilnadu

Ministers of Environment and Forests Ministry - India & Tamilnadu

Government of INDIA:

Minister - Shri. Jairam Ramesh

Government of Tamilnadu:

Minister for Forests : Thiru K.T Pachamal
Minister for Environment : Thiru T.K.M Chinnayya