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SHARATHRAJ P.R.CHM S5

ROLL NO :35

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INTRODUCTION

HISTORY

WORKING

PULSE OX

COLOR VISION CALIBRATION

CURVED MIRROR

LIDAR

LASER OSCILLOSCOPE

ADVANTAGE

PROBLEMS WITH BREATHLYZER

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Back in the day when science magazines had science, a kidcould find all sorts of laser spy devices, and even the plansto build them.

A popular instrument usually found in the back pages nextto the X-ray specs was the window-bounce remote lasermicrophone.

With a little effort one could detect vibrations in the glassmade by sounds by bouncing a laser off the window.

A new kind of stealthy laser device is under developmentat the Military University of Technology in Warsaw and sofar, testing has been fairly successful.

Using this tool, law enforcement could potentially triagedrivers for a DUI workup by remotely sensing alcohol vaporin the cab as they drive through their trap.

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The study of alcohol as an academic exercise, however,can be traced to the late 1700s when J.J. perlent proposedthe chemical identification of poisons

In the United States, Indiana University's Prof. Rolla N.

Harger conducted the first-ever "short course" on chemicaltests for intoxication in 1937. Dr. harger also introducedthe Drunk meter, the first stable instrument for testingbreath alcohol, in 1938.

In 1954, Professor Robert F. Borkenstein of Indiana

University invented the Breathalyzer, the first practicalinstrument for testing breath alcohol. Whereasthe drankometre required re-calibration when it wasmoved from place to place, the Breathalyzer was highlyportable.

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http://www.digitaltrends.com/wp-content/uploads/2014/06/remote-sensing-alcohol-vapor.png

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http://www.digitaltrends.com/wp-content/uploads/2014/06/remote-sensing-alcohol-vapor.png

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The device itself actually needs four lasers to even begin to have any kind ofaccuracy.

To see why lets consider another police trick used to keep the peace the LIDAR(LIDAR is a portmanteau of light and radar) speed gun.

Radar guns based on the Doppler effect work fine if youre the only car on the road,but in traffic something that holds up better in court is needed.

LIDAR provides this accuracy by using time-of-flight detection and the laserlikefocus of well, the laser.

The main sources of inaccuracies in LIDAR are due to differential absorption andscattering of the beam by things like water vapor, dust, windows, and pigments.

One way some people try to foil LIDAR is to use special paints and clear-coats thatabsorb specifically in the 905 nm wavelength used by speed guns.

One way to account for these inherent sources of error, is to use a technique knownas differential absorption LIDAR, or DIAL essentially using two beams withseparate wavelengths, which interact differently with the same material.

The Warsaw team basically uses the same trick, but to specifically detect alcoholthey rely on color vision so to speak.

Ethyl alcohol has a wide absorption band around 3.39 m (3390 nm), while that ofwater vapor, which will also be present, is around 3 m (3000 nm).

The team therefore choose to use a 3.39 m HeNe laser to see the alcohol, and a

1.5 m diode reference beam to discriminate it from water. This is all standard laser fare, the same kind of technology used in pulse-ox to

measure oxygen in your blood.

WORKING

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A blood-oxygen monitor displays the percentage of bloodthat is loaded with oxygen. Morespecifically, it measures what percentage of hemoglobin, the protein in blood that carries oxygen,is loaded.

Acceptable normal ranges for patients without pulmonary pathology are from 95 to 99 percent.

For a patient breathing room air at or near sealevel. an estimate of arterial pO2can be made fromthe blood-oxygen monitor saturation peripheral oxygen (SpO2) reading.

Pulse oximetry is a particularly convenient noninvasivemeasurement method.

Typically it utilizes a processor and a pair of small light-emitting diodes(LEDs) facing

a photodiodethrough a translucent part of the patient's body, usually a fingertip or an earlobe. OneLED is red, with wavelengthof 660 nm, and the other is infraredwith a wavelength of 940 nm.

Absorption of light at these wavelengths differs significantly between blood loaded with oxygenand blood lacking oxygen.

Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through.

Deoxygenated hemoglobin allows more infrared light to pass through and absorbs more red light.The LEDs flash about thirty times per second.

The photodiode measures the amount of light that is transmitted (in other words, that is notabsorbed).

The measurement fluctuates in time because the amount of arterial blood that is presentincreases (literally pulses) with each heartbeat.

By subtracting the minimum transmitted light from the peak transmitted light in each wavelength,the effects of other tissues is corrected for.

The ratio of the red light measurement to the infrared light measurement is then calculated bythe processor (which represents the ratio of oxygenated hemoglobin to deoxygenatedhemoglobin), and this ratio is then converted to SpO2by the processor via a lookup table.

http://en.wikipedia.org/wiki/Hemoglobinhttp://en.wikipedia.org/wiki/Hemoglobinhttp://en.wikipedia.org/wiki/Oxygenation_(medical)http://en.wikipedia.org/wiki/Oxygenation_(medical)http://en.wikipedia.org/wiki/Noninvasivehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Lookup_tablehttp://en.wikipedia.org/wiki/Lookup_tablehttp://en.wikipedia.org/wiki/Lookup_tablehttp://en.wikipedia.org/wiki/Infraredhttp://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Noninvasivehttp://en.wikipedia.org/wiki/Oxygenation_(medical)http://en.wikipedia.org/wiki/Hemoglobin

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Color visionis the ability of an organism ormachine to distinguish objects based onthe wavelengths(or frequencies) ofthe light reflect, emit, or transmit.

Colorscan be measured and quantified invarious ways;

indeed, a human's perception ofcolors is asubjective process whereby the brainrespondsto the stimuli that are produced when incominglight reacts with the several types of cone

photoreceptorsin the eye. In essence, different people see the same

illuminated object or light source in differentways.

http://en.wikipedia.org/wiki/Wavelengthhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Reflected_lighthttp://en.wikipedia.org/wiki/Light_emissionhttp://en.wikipedia.org/wiki/Transmittancehttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Eyehttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Eyehttp://en.wikipedia.org/wiki/Eyehttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Cone_cellhttp://en.wikipedia.org/wiki/Brainhttp://en.wikipedia.org/wiki/Colorhttp://en.wikipedia.org/wiki/Transmittancehttp://en.wikipedia.org/wiki/Light_emissionhttp://en.wikipedia.org/wiki/Reflected_lighthttp://en.wikipedia.org/wiki/Lighthttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Wavelength

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Calibrationis a comparison between measurements one of knownmagnitude or correctness made or set with one device and anothermeasurement made in as similar a way as possible with a second device.

The device with the known or assigned correctness is called the standard.

The second device is the unit under test, test instrument, or any ofseveral other names for the device being calibrated.

The formal definition of calibration by the International Bureau ofWeights and Measuresis the following: "Operation that, under specifiedconditions,

in a first step, establishes a relation between the quantity values withmeasurement uncertainties provided by measurement standards andcorresponding

Indications with associated measurement uncertainties (of the calibratedinstrument or secondary standard) and,

in a second step, uses this information to establish a relation forobtaining a measurement result from an indication."

http://en.wikipedia.org/wiki/Standard_(metrology)http://en.wikipedia.org/wiki/Device_under_testhttp://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measureshttp://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measureshttp://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measureshttp://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measureshttp://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measureshttp://en.wikipedia.org/wiki/Device_under_testhttp://en.wikipedia.org/wiki/Standard_(metrology)

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A curved mirroris a mirrorwith a curved reflectivesurface, which may be either convex(bulgingoutward) or concave(bulging inward).

Most curved mirrors have surfaces that are shaped

like part of a sphere, but other shapes are sometimesused in optical devices.

The most common non-spherical type are parabolicreflectors, found in optical devices such as reflectingtelescopesthat need to image distant objects, sincespherical mirror systems, like spherical lenses, sufferfrom spherical aberration.

One advantage that mirror optics have over lensoptics is that mirrors do not introduce chromaticaberration.

http://en.wikipedia.org/wiki/Mirrorhttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Parabolic_reflectorhttp://en.wikipedia.org/wiki/Parabolic_reflectorhttp://en.wikipedia.org/wiki/Reflecting_telescopehttp://en.wikipedia.org/wiki/Reflecting_telescopehttp://en.wikipedia.org/wiki/Spherical_aberrationhttp://en.wikipedia.org/wiki/Chromatic_aberrationhttp://en.wikipedia.org/wiki/Chromatic_aberrationhttp://en.wikipedia.org/wiki/Chromatic_aberrationhttp://en.wikipedia.org/wiki/Chromatic_aberrationhttp://en.wikipedia.org/wiki/Spherical_aberrationhttp://en.wikipedia.org/wiki/Reflecting_telescopehttp://en.wikipedia.org/wiki/Reflecting_telescopehttp://en.wikipedia.org/wiki/Parabolic_reflectorhttp://en.wikipedia.org/wiki/Parabolic_reflectorhttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Mirror

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Easy and Efficient To Test

Quick and Accurate Results

Helpful For Organizations and Police

Breathalyzers are portable hand held Breathalyzers provide quick and accurate

results in few seconds. The alcohol detection

sensor in breathalyzers is sensitive enough to

detect presence of alcohol with considerableaccuracy.

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Significance

Breathalyzers do not measure your blood

alcohol content (BAC) as a blood test would.

Rather, they use an algorithm to estimateyour blood alcohol concentration.

Alcohol Source

The Breathalyzer works on the assumption

that all of the air blown into it comes fromdeep inside the lungs; a blood alcohol

concentration percentage is then determined

using a programmed ratio ..

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