Wind Energy

Wind Energy

Watch this educational wind energy video and have fun making a model windmill. Learn about wind generators before you make a model windmill for yourself, watch it in action and then calculate its power output.

Learn more about energy, power, work, joules and watts thanks to the handy information and instructions given in the video clip.

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Steel Wool & Vinegar Reaction

Steel Wool & Vinegar Reaction

Soak steel wool in vinegar and watch what happens as the iron in the steel begins to react with the oxygen around it. This fun science experiment for kids is great for learning about chemical reactions.

What you'll need: Steel Wool Vinegar Two beakers Paper or a lid (something to cover the beaker to keep the heat in) Thermometer Instructions: Place the steel wool in a beaker. Pour vinegar on to the steel wool and allow it to soak in the vinegar for around one minute. Remove the steel wool and drain any excess vinegar. Wrap the steel wool around the base of the thermometer and place them both in the second beaker. Cover the beaker with paper or a lid to keep the heat in (make sure you can still read the temperature on the thermometer, having a small hole in the paper or lid for the thermometer to go through is a good idea). Check the initial temperature and then monitor it for around five minutes. What's happening? The temperature inside the beaker should gradually rise, you might even notice the beaker getting foggy. When you soak the steel wool in vinegar it removes the protective coating of the steel wool and allows the iron in the steel to rust. Rusting (or oxidation) is a chemical reaction between iron and oxygen, this chemical reaction creates heat energy which increases the temperature inside the beaker. This experiment is an example of an exothermic reaction, a chemical reaction that releases energy in the form of heat.

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Escaping Water

Escaping Water

Water can certainly move in mysterious ways, get the water from one cup to make its way up hill and back down into a second empty cup with the help of paper towels and an interesting scientific process.

What you'll need: A glass of water An empty glass Some paper towels Instructions: Twist a couple of pieces of paper towel together until it forms something that looks a little like a piece of rope, this will be the 'wick' that will absorb and transfer the water (a bit like the wick on a candle transferring the wax to the flame). Place one end of the paper towels into the glass filled with water and the other into the empty glass. Watch what happens (this experiment takes a little bit of patience). What's happening? Your paper towel rope (or wick) starts getting wet, after a few minutes you will notice that the empty glass is starting to fill with water, it keeps filling until there is an even amount of water in each glass, how does this happen? This process is called 'capillary action', the water uses this process to move along the tiny gaps in the fibre of the paper towels. It occurs due to the adhesive force between the water and the paper towel being stronger than the cohesive forces inside the water itself. This process can also be seen in plants where moisture travels from the roots to the rest of the plant.

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Plant Seeds & Watch Them Grow

Plant Seeds & Watch Them Grow Learn about seed germination with this fun science experiment for kids. Plant some seeds and follow the growth of the seedlings as they sprout from the soil while making sure to take proper care of them with just the right amount of light, heat and water. Have fun growing plants with this cool science project for children.

What you'll need: Fresh seeds of your choice such as pumpkins seeds, sunflower seeds, lima beans or pinto beans. Good quality soil (loose, aerated, lots of peat moss), if you don’t have any you can buy some potting soil at your local garden store. A container to hold the soil and your seeds. Water. Light and heat. Instructions: Fill the container with soil. Plant the seeds inside the soil. Place the container somewhere warm, sunlight is good but try to avoid too much direct sunlight, a window sill is a good spot. Keep the soil moist by watering it everyday (be careful not to use too much water). Record your observations as the seeds germinate and seedlings begin to sprout from the seeds. What's happening? Hopefully after a week of looking after them, your seedlings will be on their way. Germination is the process of a plant emerging from a seed and beginning to grow. For seedlings to grow properly from a seed they need the right conditions. Water and oxygen are required for seeds to germinate. Many seeds germinate at a temperature just above normal room temperature but others respond better to warmer temperatures, cooler temperatures or even changes in temperature. While light can be an important trigger for germination, some seeds actually need darkness to germinate, if you buy seeds it should mention the requirements for that specific type of seed in the instructions. Continue to look after your seedlings and monitor their growth. For further experiments you could compare the growth rates of different types of seeds or the effect of different conditions on their growth.

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Static Electricity Experiment

Static Electricity Experiment

What you'll need: 2 inflated balloons with string attached Your hair Aluminium can Woolen fabric Instructions: Rub the 2 balloons one by one against the woolen fabric, then try moving the balloons together, do they want to or are they unattracted to each other? Rub 1 of the balloons back and forth on your hair then slowly it pull it away, ask someone nearby what they can see or if there's nobody else around try looking in a mirror. Put the aluminium can on its side on a table, after rubbing the balloon on your hair again hold the balloon close to the can and watch as it rolls towards it, slowly move the balloon away from the can and it will follow. What's happening? Rubbing the balloons against the woolen fabric or your hair creates static electricity. This involves negatively charged particles (electrons) jumping to positively charged objects. When you rub the balloons against your hair or the fabric they become negatively charged, they have taken some of the electrons from the hair/fabric and left them positively charged. They say opposites attract and that is certainly the case in these experiments, your positively charged hair is attracted to the negatively charged balloon and starts to rise up to meet it. This is similar to the aluminium can which is drawn to the negatively charged balloon as the area near it becomes positively charged, once again opposites attract. In the first experiment both the balloons were negatively charged after rubbing them against the woolen fabric, because of this they were unattracted to each other.

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Average Symbol Error Probability of General-Order Rectangular Quadrature Amplitude Modulation of Optical Wireless Communication Systems Over Atmospheric Turbulence Channels

Average Symbol Error Probability of General-Order Rectangular Quadrature Amplitude Modulation of Optical Wireless Communication Systems Over Atmospheric Turbulence Channels


Abstract—Using an accurate exponential bound for
the Gaussian Q-function, we derive simple approximate
closed-form expressions for the average symbol
error probability (ASEP) of a free-space optical communication
link using subcarrier intensity modulation
(SIM) with general-order rectangular quadrature
amplitude modulation (QAM) over atmospheric
turbulence channels. To model the atmospheric turbulence
conditions, the log-normal and the gammagamma
distribution are used. Extensive numerical
and computer simulation results are presented in order
to verify the accuracy of the proposed mathematical
analysis.

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Free-Space Optical Communication Through Atmospheric Turbulence Channels

Free-Space Optical Communication Through
Atmospheric Turbulence Channels




Abstract—In free-space optical communication links, atmospheric
turbulence causes fluctuations in both the intensity and
the phase of the received light signal, impairing link performance.
In this paper, we describe several communication techniques to
mitigate turbulence-induced intensity fluctuations, i.e., signal
fading. These techniques are applicable in the regime in which the
receiver aperture is smaller than the correlation length of fading
and the observation interval is shorter than the correlation time
of fading. We assume that the receiver has no knowledge of the
instantaneous fading state. When the receiver knows only the
marginal statistics of the fading, a symbol-by-symbol ML detector
can be used to improve detection performance. If the receiver
has knowledge of the joint temporal statistics of the fading, maximum-
likelihood sequence detection (MLSD) can be employed,
yielding a further performance improvement, but at the cost of
very high complexity. Spatial diversity reception with multiple
receivers can also be used to overcome turbulence-induced fading.
We describe the use of ML detection in spatial diversity reception
to reduce the diversity gain penalty caused by correlation between
the fading at different receivers. In a companion paper, we
describe two reduced-complexity implementations of the MLSD,
which make use of a single-step Markov chain model for the
fading correlation in conjunction with per-survivor processing.
Index Terms—Atmospheric turbulence, free-space optical

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Performance Analysis of Decode-and-Forward Relaying in Gamma-Gamma Fading Channels

Performance Analysis of Decode-and-Forward
Relaying in Gamma-Gamma Fading Channels

Manav R. Bhatnagar, Member, IEEE

Abstract—We analyze performance of the decode-and-forward
(DF) protocol in the free space optical (FSO) links following
the Gamma-Gamma distribution. The cumulative distribution
function (cdf) and probability density function (pdf) of a random
variable containing mixture of the Gamma-Gamma and Gaussian
random variables is derived. By using the derived cdf and pdf,
average bit error rate of the DF relaying is obtained.

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IEEE papers A COHERENT FREE SPACE OPTICAL LINK FOR LONG DISTANCE CLOCK COMPARISION, NAVIGATION, AND COMMUNICATION: THE MINI-DOLL PROJECT

A COHERENT FREE SPACE OPTICAL LINK FOR LONG DISTANCE CLOCK
COMPARISON, NAVIGATION, AND COMMUNICATION:
THE MINI-DOLL PROJECT

ABSTRACT

We describe the realization of a 5 km free space coherent optical link through the turbulent atmosphere between 

a telescope and a ground target. We present the phase noise of the link, limited mainly by atmospheric 

turbulence and mechanical vibrations of the telescope and the target. We discuss the implications of our results 

for applications, with particular emphasis on optical Doppler ranging to satellites and long distance frequency 

transfer.

For full paper mail me to kamalakannanmsajce@gmail.com

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IEEE Papers on fiber optical communication ATMOSPHERIC CHANNEL EFFECTS ON TERRESTRIAL FREE SPACE OPTICAL COMMUNICATION LINKS

ATMOSPHERIC CHANNEL EFFECTS ONTERRESTRIAL FREE SPACE OPTICALCOMMUNICATION LINKS

Abstract.

This paper illustrates the challenges imposed by the

atmospheric channel on the design of a terrestrial laser communication link.

The power loss due to scattering effect is described using the Kim/Kruse

scattering model while the effect and the penalty imposed by atmospheric

turbulence is highlighted by considering the bit error rate (BER) of an On-

Off Keying modulated link in an optical Poisson channel. The power loss due

to thick fog can measure over 100 dB/km while snow and rain result in much

lower attenuation. We show that non-uniformity in the atmospheric

temperature also contributes to performance deterioration due to

scintillation effect. At a BER of 10-4, for a channel with a turbulence strength

of >0.1, the penalty imposed by turbulence induced fading is over 20

photoelectron counts in order to achieve the same level of performance as a

channel with no fading. The work reported here is part of the EU COST

actions and EU projects

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ieee papers

The Design and Implementation of Remote Real Time Monitor System for Embedded 
Devices Based on GPRS 

ABSTRACT

We develop a remote monitoring system on environmental quality of Heihe river basin. The system consists of client and server, client is responsible for collecting data. We use multi-thread approach to develop server software, realizing online monitoring of sensor device, data management and log management and so on. Server uses Socket programming to communicate with client, the system has been running on the server.

LINK

http://ieeexplore.ieee.org/xpl/articleDetails.jsp;jsessionid=pL2PPYRV0FJ8KHcn5cFzxhdDLL41GGzB82vY0tVyvxM3hdpBLHPh!-2011277867?arnumber=6187990&contentType=Conference+Publications

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Home-made Stethoscope

Purpose

To demonstrate how sound waves can travel through enclosed spaces and become aplified by creating a home-made stethoscope.

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Additional information

The stethoscope was invented in 1816 by French physician and inventor René-Théophile-Hyacinthe Laennec. The idea came to Laennec when he witnessed children playing with a long piece of wood that transmitted the sound of pins scratching the surface. After making the observation, the next day he rolled up a piece of paper into the shape of a funnel. He then used it to listen to the chests of his patients. Discovering the funnel amplified the sounds from his patients chests, Laennec (who had a background in carpentry) built a 25cm by 2.5cm hollowed wooden cylinder. This cylinder replaced the rolled up paper tube as a device to listen to his patients chest. He later modified this device with detachable parts. He notated the various sounds he heard with his primitive stethoscope and related them to anatomical findings at his patients autopsies. He published his findings in 1819 and the stethoscope, derived from the Greek word "stethos" (meaning chest), was born. As he neared death Laennec often referred to the stethoscope as "the cylinder" and bequeathed his own stethoscope to his nephew, accurately referring to it as the "the greatest legacy" of his life.

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Sponsored Links

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Required materials

• 2 Funnels
• Old garden hose (it will need to be cut-up)
• Scissors
• Modeling clay
• Pen or pencil
• Journal

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Estimated Experiment Time

About 15 minutes

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Step-By-Step Procedure

• 1. Use your scissors to cut a piece of garden hose approximately 16 inches in length. Make sure to cut from the middle of the house as you'll need both ends to be even (don't use the end that connects to outdoor faucets).
• 2. Place one of the funnels onto the end of the garden hose. If it doesn't fit tightly, use some modeling clay to secure it.
• 3. Repeat step 2 with the other funnel on the other end of the garden hose.
• 4. Place one end of the funnel over your heart and the other end over your ear. What do you hear? Count your heartbeat rate for 30 seconds and note them in your journal.
• 5. Do some jumping jacks, run around, exert a lot of energy for about 1 minute.
• 6. Use your stethoscope again, with one end over your heart and one end to your ear. Now what do you hear? Again count your heart beat rate for 30 seconds and note them in your journal.

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Note

If you're having trouble cutting the garden hose with a scissor, you may need to use a sharp knife or razor. As always, make sure you have the help of an adult when cutting objects!

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Observation

Can you think of other materials you could use to create a home-made stethoscope? What other purposes, beyond listening to your heartbeat, can you find for the stethoscope?

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Result

Stethoscopes can measure the rate of your heart and assist in determining how many times your heart beats per minute. The stethoscope works on the simple principle of acting as a sound amplifier that carries the sound along the hose to your ears.

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Vibrating Coin

Purpose

To demonstrate the expansion of air when heated.

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Additional information

The temperature of a gas is directly proportional to the speed with which its molecules move. Increasing the temperature of a gas results in an increase of the average speed (and therefore the kinetic energy) of its molecules. This in turn causes the molecules to ‘spread out’ by virtue of a phenomenon known as thermal expansion.

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Sponsored Links

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Required materials

• Coin
• Bottle
• Refrigerator
• Water

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Estimated Experiment Time

Approximately 15 to 20 minutes

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Step-By-Step Procedure

• 1. Place an empty bottle in a refrigerator to cool
• 2. Place the cooled bottle outside
• 3. Dip your finger in water and place a few drops around mouth of the bottle and the edge of the coin
• 4. Place a coin on the mouth of the bottle
• 5. Place both your hands around the bottle; hold firmly
• 6. Remove your hands after a while

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Note

• Use a bottle with a mouth narrow enough to be closed completely with a coin.
• Applying water on the rim of the bottle mouth and the coin’s edge will help seal the bottle.

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Observation

In approximately fifteen seconds from covering the bottle with your hands, the coin will start to vibrate up and down. When you do remove your hands after a short while, the coin continues to vibrate.

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Result

As soon as the bottle is taken out of the refrigerator the temperature of the gas inside the bottle begins to rise; encasing the bottle with your hands increases the temperature further. When the bottle is heated, the air molecules inside it start moving faster and these molecules collide with the coin with more energy. This results in increased pressure which in turn is caused by the expanding air that escapes though the rim of the coin and makes it vibrate.

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Measuring Water pH

Water pH

Purpose

To determine the pH level of both city water and well water to determine which is more basic and which is more acidic.

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Additional information

Many people report that well water is better for you than city water. They also report that it tastes better, as well water does not undergo chemical treatment when city water does.

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Sponsored Links

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Required materials

• 2 test tubes or other small container for water collection
• 20 pH strips with guide
• Journal or logbook
• Source of city water
• Source of well water
• Test tube labels or labeling marker

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Estimated Experiment Time

This experiment will most likely take several hours.

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Step-By-Step Procedure

• 1. Label one of the test tubes “City Water” and make sure you are only using this test tube for that type of water.
• 2. Collect one sample of water and use the pH strip to test its pH level. Record your findings.
• 3. Repeat step two with nine more samples of city water, for a total of ten city water samples.
• 4. Label the second test tube “Well Water” and make sure you are only using this test tube for that type of water.
• 5. Repeat steps two and three for the well water.

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Note

The pH strips can easily be found at your local home and garden supply store. You can use the same test strips that are used to test the pH of pools or ponds, as long as they are pH testing strips and come with a color guide that allows you to accurately determine the pH level of the water from the used strips.

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Observation

You can tape the test strips in your journal as part of your observation or use them as part of your science fair project display. You can also create a graph of your findings to easily display the pH information of both the city and well water.

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Result

The results of the experiment depend on the information obtained from the pH strips for both types of water. Did one type of water exhibit a higher or lower pH level than the other? If so, how much of a difference was there? Were the pH levels about the same? Based on the information obtained during your experiment, which type of water do you think is the best for drinking?

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Measuring Air Pollution

Measuring Air Pollution

Purpose

To determine the amount of foreign particles in the air in a specific area.

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Additional information

Breathing air is vital to our existence, but have you ever thought you might not be breathing purely clean air? This simple experiment will give you an idea of how “dirty” your air is.

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Required materials

• White posterboard
• Scissors
• Vaseline
• String
• Hole punch
• Magnifying glass
• Permanent black marker
• Journal or notebook

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Estimated Experiment Time

About a week.

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Step-By-Step Procedure

• 1. Find an area in which you can hang several cut out pieces of the posterboard. You can do this in your home if you’d like to find out how clean the air in your home is, or you can hang the cut out pieces of posterboard outside in your yard or another area.
• 2. Cut the posterboard into several squares.
• 3. Draw a square with the marker on each cut out piece of posterboard, a little smaller than the square itself.
• 4. Punch a hole in the top of each piece of posterboard and tie pieces of string in the holes so you can hang the cut outs in various areas.
• 5. Smear a thin layer of Vaseline inside the drawn square on each cut out and hang them in different places within the area you’ve chosen. Record the areas you’ve hung each cut out in your notebook.
• 6. In about a week, collect your squares.

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Observation

With the magnifying glass, count how many particles you can see stuck to the Vaseline in each square. Record the number of particles, as well as the location of each cut out in your journal.

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Result

You will most likely find some amount of particles stuck to the cut outs. Are there a lot of particles or just a few? How do you think the area you’ve chosen to perform the experiment in has affected your results? What do you think would happen if you performed this experiment in a heavily polluted area, such as a big city or an area with known air pollution? Do you think you would find more particles stuck to the cut outs? How do you think the particles in the air affects the air quality and our ability to breathe well?

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