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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BPSK Subcarrier Intensity Modulated Free-Space Optical Communications in Atmospheric Turbulence Wasiu O. Popoola, Student Member, IEEE, and Zabih Ghassemlooy, Senior Member, IEEE

BPSK Subcarrier Intensity Modulated Free-Space
Optical Communications in Atmospheric Turbulence
Wasiu O. Popoola, Student Member, IEEE, and Zabih Ghassemlooy, Senior Member, IEEE




Abstract—Free-space optical communications (FSO) propagated
over a clear atmosphere suffers from irradiance fluctuation
caused by small but random atmospheric temperature fluctuations.
This results in decreased signal-to-noise ratio (SNR) and
consequently impaired performance. In this paper, the error
performance of the FSO using a subcarrier intensity modulation
(SIM) based on a binary phase shift keying (BPSK) scheme in
a clear but turbulent atmosphere is presented. To evaluate the
system error performance in turbulence regimes from weak to
strong, the probability density function (pdf) of the received
irradiance after traversing the atmosphere is modelled using the
gamma-gamma distribution while the negative exponential distribution
is used to model turbulence in the saturation region and
beyond. The effect of turbulence induced irradiance fluctuation
is mitigated using spatial diversity at the receiver. With reference
to the single photodetector case, up to 12 dB gain in the electrical
SNR is predicted with two direct detection PIN photodetectors in
strong atmospheric turbulence



for full paper mail me

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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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Performance Analysis of a Laser Ground-Station-to-Satellite Link With Modulated Gamma-Distributed Irradiance Fluctuations

Performance Analysis of a Laser
Ground-Station-to-Satellite Link With
Modulated Gamma-Distributed
Irradiance Fluctuations






Abstract—The performance of a ground-station-to-space

laser uplink with a Gaussian-beam wave model subject to

turbulence and beam wander effects is the topic of the

present study. The modulated gamma distribution is used to

describe the combined effect of the above two deteriorating

factors. At first, a versatile expression of the above probability

density function is deduced. We then derive novel closedform

expressions for its cumulative distribution function

and the moment-generating function. The scintillation index

and the probability of fade are hence readily evaluated. The

analysis is completed with the evaluation of the bit error

rate assuming heterodyne detection with differential phaseshift

keying. In order to attain an adequate error rate target,

we incorporate diversity at the satellite receiver. A proper

simulation scenario is adopted, and numerical results are

provided to verify the accuracy of the derived expressions.

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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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ieee papers

Power and safety management of electrical appliances in a smart power distribution 
system Using RFID

ABSTRACT

This paper introduces a low-cost solution to the on/off control of home appliances using a new power distribution system, and discusses how the system contributes to the safe and convenient use of the appliances. In the proposed system, with an RFID tag in the plug and newly-designed sockets/power strips, the smart meter identifies appliances connected to individual (wall) sockets simply by connecting the appliances to the socket. 

LINK

http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5722711&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D5722711

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