Assignment

dIRECT-sENSING

Direct Sensing, Inc. offers a wide range of scanning, sensing, and screening instruments coupled with Cone Penetration Testing (CPT) and Direct Push Technology (DPT) services for environmental and geotechnical site investigation, analysis, and remediation. Direct Sensing Inc. (DSI) has pioneered the use of the Expedited Site Characterization Process (ESC)using the latest and most advanced sensing and scanning instruments, e.g. Membrane Interface Probe (MIP) and UVOST, to characterize the contaminants in the soil and groundwater. Either on or off-shore, our highly experienced engineers, scientists, and operators along with our fleet of CPT, DPT, and Sonic rigs can solve and properly delineate the most complex technical problems while saving time and money. DSI can accomplish this service anywhere, and with any soil condition, without sacrificing quality, and deliver the kind of results our clients expect from the leader in scientific site characterization.

DSI employs the most advanced instruments and techniques available and teams with the leaders and pioneers in the field of expedited site characterization. Whether it is combining Laser Induced Fluorescence with Cone Penetration Testing (CPT), or using state-of-the-art GC Mass Spectrometers to identify contaminants brought to the surface with a Membrane Interface Probe (MIP), DSI has the scientific instruments and the prowess to perform.

The DSI history of accomplishments of “firsts” in the site characterization industry is long:

• In 1998, DSI personnel designed one of the first MIP platforms to service clients. At the time, it was a state of the art Membrane Interface Probe (DPT/MIP) platform.
• In 2001, DSI personnel created the first Environmental Data Acquisition Vehicle (EDAV) for several MIP service providers.
• In 2004, DSI personnel developed and applied one of the first commercially available Cone Penetration Technology & Membrane Interface Probe (CPT/MIP) platforms in the US.
• In 2006, DSI personnel developed the first CPT/MIP/Fluorescence platform designed to specifically identify petroleum Non-Aqueous Phase Liquid (NAPL) with 2 cm of resolution.
• Since 2006, DSI has designed, built and perfected the technology of a “single rod strand” to acquire all of the needed analytical and scientific information on the environmental soil and groundwater condition at the site. This concept is called “Single Borehole Utilization” and focuses on maximizing the cost effectiveness of a single mobilization of a field crew to comprehensively access assess a site with reduced mobilizations.

The number of direct-sensing technologies available to direct-push units has greatly increased in the last 10 years. S2C2 can now provide direct sensing services to determine chlorinated and non chlorinated VOCs and aromatic petroleum hydrocarbon impacts coupled with continuous soil lithology data. Direct-sensing requires competent proven operators and analysts to generate high quality data.

 The experience and technological know-how gained through thousands of feet of direct-sensing sampling has been extremely valuable in interpreting data.  Pattern recognition is a key component to interpreting direct-sensing data.  Because of this experience S2C2 has been successful at mapping historic fill/native interfaces, confining units, potential contaminant preferential pathways, and metals contamination  at numerous sites throughout the urban Northeast and Mid-Atlantic states.

Advantages of Direct Sensing

• Obtain rapid VOC, Petroleum and lithologic information

• Provide “Real-Time” displays of depth, conductivity, and speed

• Determine thickness and lateral extent of lithologic units

• Limited soil sampling required to confirm log response

• No drill cuttings

• Construct detailed geologic cross sections

• Locate appropriate lateral and vertical placement of wells

• Target zones for injection of HRC®,ORC®, etc.

• Conductivity readings collected 20/secondfinish the job on-time in a variety of site conditions.

 Presentation Transcript

1. Applications of Physics Direct Sensing – Part 1 Mukesh N. Tekwani [email_address] CIE – A2 Level, Nov 2009

2. Direct Sensing A Sensor is something that tells something about its environment Electronic sensor – Gives information about its environment by generating an electrical signal. This electrical signal must change with changes in environment. E.g., if sensor measures temp, then electrical signal must change with changes in temp

3. Examples of Sensors Sensors in AC to measure room temperature, humidity Sensor in certain TV sets to measure ambient light and adjust brightness / contrast accordingly Remote control Infrared detectors used in motion sensors Magnetic proximity sensor Sound controlled devices

4. Electronic Sensor Parts of a sensor: Sensing Device – Example: LDR (L ight D ependent R esistor ) – to measure changes in light Strain gauge – to measure strain experienced by a material Important – Some physical property of the sensing device MUST change so that it can detect changes in whatever is to be monitored. Sensing Device Processing Unit Output Device

5. Electronic Sensor Parts of a sensor: Processing Unit Any change in a physical property of the sensor must be processed. (measured / converted / amplified) so that it can be indicated by an output device. Output Device The output device may be a simple lamp or a digital meter that indicates a voltage or a current – basically any device that can respond to a change in voltage. So: Connect the sensing device to the output device via a processing unit Sensing Device Processing Unit Output Device

6. Electronic Sensor

7. Light Dependent Resistor (LDR) An LDR is a resistor whose resistance changes with intensity of light falling on it. Construction: A thin film of cadmium sulphide sandwiched between two metal electrodes.

8. Light Dependent Resistor (LDR) LDR is sensitive to changes in light intensity BUT – change in resistance with change in light is NOT linear . Normally the resistance of LDR is very high ~ 100 M (in dark) In sunlight, its resistance falls to about 100 ohms   

9.  Characteristics of LDR Most LDRs will respond to light of 500 nm wavelength (yellow to green in colour) What is the mechanism by which an LDR changes its resistance with changing light levels? Photons interact with the CdS molecules Photons have sufficient energy to remove electrons These electrons then allow a current to flow

10.  LDR Characteristics

11. LDR Characteristics The previous graph is not easy to draw. We have used a linear scale for variation of light intensity. But this linear scale for light intensity is very large Light Source Illumination Moonlight 0.1 lux 60 W bulb at 1 m 50 Fluorescent lamp 500 Bright sunlight 30,000 lux

12. LDR Characteristics So we draw a graph of resistance vs log(I) A log scale does not go from 0, 1, 2, 3, 4, 5… A log scale goes like this: 10 0 , 10 1 , 10 2 , 10 3, ..

13. LDR Limited amount of current can flow else it will burn out

14. LDR Current through LDR = 10 mA = 0.01 A Voltage across LDR = 0.01 A ´ 15 V = 0.15 V Voltage across protection resistor = 9 – 0.15 = 8.85 V Resistance = 8.85 V ¸ 0.01 A = 885 ohms An LDR has a resistance of 15 ohms at a certain very high light level. What value of protection resistor is needed if a current of no more than 10 mA is to flow when the supply voltage is 9.0 V?

15. Potential Divider Circuit An output voltage Vout is obtained from a junction between the two resistors.

16. Potential Divider circuit If the output current is zero, the current flowing through R 1 also flows through R 2 , because the resistors are in series. So we can use Ohm’s Law to say:

17. But V out = IR 2 So, Vout = So, the output voltage is the same fraction of the input voltage as R 2 is the fraction of the total resistance .

18. LDR Problem What is the output voltage of this potential divider?

19. LDR Problem 4.4 V

20. LDR Will CdS LDR respond to infrared light? No. Since infrared light does not have sufficient energy, they cannot knock off

The application of electromagnetic wave

Electromagnetic wave have 7 clasification :

Radio Wave

Radio wave is part of the electromagnetic wave spectrume wich have lowest frequency or longest wavelenght. Radio wave covers a frequency range of  Hz to   Hz or the wavelength range of 1 m to  m. As signal carrier, radio wave is classified into two group, AM ( amplitudo Modulation) and FM ( frequensi modulation). The AM wave carries signal by modulation the amplitudo at constant frequency, whereas FM wave carries signal by moduating the frequency at constant amplitudo.

Based on its frequency, radio wave is classified into some categories, i.e. low frequency ( LF ), medium frequency ( MF ), hight frequency ( HF ), Very hight frequency ( VHF ) and ultra hight frequency ( UHF ).

Based on its wave lenght, radio wave is classified into shroth wave ( SW ), medium wave 9 MW ), and Long wave ( LW ).

1.      Microwave

Microwave has frequency range of Hz to to  Hz or a wavelenght range of to  m to to  m.

Microwave is assumsed as the highest frequency of radio wave or the shortest wavelenght of radio wave. Therefore, sensing system that use microwave is called Radar ( Radio detection and ranging ), it still uses the word “ Radio”.

Radar  is used to detect objects in a distant. Basically, radar system consist of wave transmitter adn wave receiver. The wave transmitter emits wave to certain directions. Whenever that wave come accros a solid object, espesially metal, a radar wave will be reflected. The reflected wave is then detected by the wave receiver in the radar system. By measuring the time interval between wave tranmission and the reception of reflected wave, the distance between radar system and the detected object can be determined.

If the time interval between the wwave transmission and reception of reflected wave in a radar system is t and the distance between the object and radar system is a, this following equation apllies :

S =

2.      Infrared Ray

Infrared ray covers the frequency range of  to  Hz or the wavelenght frequency of  m to  m. Infrared radiation is the produced by atomic vibration of matter.

Infrared ray is able to penetrate fog and thick clouds. Yaht is why, it can be used take photograf of a distant object covered by fog or cloud. Infrared is widely used in the military to increase fireaccuracy and to detect object using the heat emited by those object.

In astronomy, infrarzed ray is very helpful in imaging object covered by fog or cloud. In science and rresearch, infrared can be used to study the structue of molecule using spectroscopy technique.

Infrared is also used in short range wireless communication. An example is to transfer file from one cell phone to another, or from a cell phone to a computer or vice versa.

3.      Visible light

Visible light covers the frequency range of 4.3 x  to 7.5  Hz or a wvelenght of 4,0000 angstrom to 7,000 angstrom. This spectrume of electromagnetic wave is known as the visible light because it can be seen by the naked eyes.

Visible llight spectrume consist of red light to violet light. Red light is part of this visible light spectrume that have the lowest frequency or the longest wavelenght. Whereas violet light is a part of visible light spectrum which has highest frequency or the shortest wavelenght.

Look at rainbow! Those are the color of visinble light. Pay attention to the order of the color.

In every day life, visible light is used as part of light decoration of stage. Lighting with colorful lights give the cheerful image. Visible light is also used in communication system and optic.

4.      Ultraviolet Ray

Ultraviolet ray spectrume covers the frequency  to  Hz or the wavelenght range of  m to  m.

Ultraviolet ray has sufficient chemical energy to disperse fluoroscent subtance and to kill germ. Ultraviolet ray is detrimental to healt. Long exposure to ultraviolet ray might damage the skin and even cause skin cancer.

Actually, sunlight also constain ultraviolet. But the intensity is not that dangerous as it has been reduce by the ozone layer (  ) in the atmosphere. You know the effect or ozone layer depletion right, don’t you?

In everyday life, ultraviolet ray utilization can be found in counterfeit money detector. This device is noedays a standart equiptment in banks and supermarkets.

5.      X-Ray

X-Ray discovered by wilhem conrad rontgent, that is why it is often called rontgent ray. X-ray cover a frequency range of  Hz to  Hz or a wavelenght range of  m to  m.

X-ray is ableto penetrate papers and humanskin, but it cannot penetrate metal or bones. Therefore it is used to image bones structure and organs whitin human body without requiring any surgery.

6.      Gamma Ray

Gamma ray (g ) is part of the electromagnetic wave spectrume with the higest frequency or the shortest wavelenght. It cover the frequency range of  Hz to  Hz, or the wavelenght range of  m to  m.

Gamma ray has a very strong penetrating ability. It can pierce throuht metals up to  few centimeters. Gamma ray is produced by unstable atoms of radioactive elements. It can also be used to sterilized medical instrumens.

The difference between X-Ray and g-ray lies in their origin. X-ray occurs due to the electrone activity of an atom, whereas gamma ray priduced by nuclear activity.

Any presence of gamma ray can be recogn ized by a detector. Gamma ray can cause damage a human health. People living in an area of gamma ray exposure have protect themself with protection shield.

 Article

Blackbody Radiation

The wave theory of light, which Maxwell’s equations captured so well, became the dominant light theory in the 1800’s (surpassing Newton’s corpuscular theory, which had failed in a number of situations). The first major challenge to the theory came in explaining thermal radiation, which is the type of electromagnetic radiation emitted by objects because of their temperature.

Testing Thermal Radiation

An apparatus can be set up to detect the radiation from an object maintained at temperature T₁. (Since a warm body gives off radiation in all directions, some sort of shielding must be put in place so the radiation being examined is in a narrow beam.) Placing a dispersive medium (i.e. a prism) between the body and the detector, the wavelengths (lambda) of the radiation disperse at an angle (theta). The detector, since it’s not a geometric point, measures a range delta-theta which corresponds to a range delta-lambda, though in an ideal set-up this range is relatively small.

If I represents the total intensity of the electromagnetic radiation at all wavelengths, then that intensity over an interval delta-lambda (between the limits of lambda and delta-lamba) is:

delta-I = R(lambda) delta-lambda

R(lambda) is the radiancy, or intensity per unit wavelength interval. In calculus notation, the delta-values reduce to their limit of zero and the equation becomes:

dI = R(lambda) dlambda

The experiment outlined above detects dI, and therefore R(lambda) can be determined for any desired wavelength.

Radiancy, Temperature, and Wavelength

Performing the experiment for a number of different temperatures, we obtain a range of radiancy vs. wavelength curves, which yield significant results:

1. The total intensity radiated over all wavelengths (i.e. the area under the R(lambda) curve) increases as the temperature increases.

This is certainly intuitive and, in fact, we find that if we take the integral of the intensity equation above, we obtain a value that is proportional to the fourth power of the temperature. Specifically, the proportionality comes from Stefan’s law and is determined by the Stefan-Boltzmann constant (sigma) in the form:

I = sigma T⁴

2. The value of the wavelength lambda_max at which the radiancy reaches its maximum decreases as the temperature increases.

The experiments show that the maximum wavelength is inversely proportional to the temperature. In fact, we have found that if you multiply lambda_max and the temperature, you obtain a constant, in what is known as Wein’s displacement law:

lambda_max T = 2.898 x 10^-3 mK

Blackbody Radiation

The above description involved a bit of cheating. Light is reflected off objects, so the experiment described runs into the problem of what is actually being tested. To simplify the situation, scientists looked at a blackbody, which is to say an object that does not reflect any light.

Consider a metal box with a small hole in it. If light hits the hole, it will enter the box, and there’s little chance of it bouncing back out. Therefore, in this case, the hole, not the box itself, is the blackbody. The radiation detected outside the hole will be a sample of the radiation inside the box, so some analysis is required to understand what’s happening inside the box.

1. The box is filled with electromagnetic standing waves. If the walls are metal, the radiation bounces around inside the box with the electric field stopping at each wall, creating a node at each wall.
2. The number of standing waves with wavelengths between lambda and dlambda is

N(lambda) dlambda = (8pi V / lambda⁴) dlambda

where V is the volume of the box. This can be proven by regular analysis of standing waves and expanding it to three dimensions.

3. Each individual wave contributes an energy kT to the radiation in the box. From classical thermodynamics, we know that the radiation in the box is in thermal equilibrium with the walls at temperature T. Radiation is absorbed and quickly reemitted by the walls, which creates oscillations in the frequency of the radiation. The mean thermal kinetic energy of an oscillating atom is 0.5kT. Since these are simple harmonic oscillators, the mean kinetic energy is equal to the mean potential energy, so the total energy is kT.
4. The radiance is related to the energy density (energy per unit volume) u(lambda) in the relationship

R(lambda) = (c / 4) u(lambda)

This is obtained by determining the amount of radiation passing through an element of surface area within the cavity.

 

Lesson Plan

Study Program                      : Physics Education

Subject           Lesson : Elementary Physics Practice Part ISubjectS                        : Electromagnetic Wave and Its Applications

Time Allotment                      : 1 x 45’          

Meeting                                  : 1^st

Competence Of Standard:

6. Understanding concept and principle of electromagnetic wave

Basic Of Competence:

6.2  Explain the electromagnetic wave application in everyday life

Indicators (s)  :

1.identified the use of electromagnetic waves (such as infrared, ultraviolet, laser light, etc.) in health and industrial

2.explain the differences in the use of a range of frequencies / wavelengths in the radio communications, radar, telephone, etc

Objective(s):

1.Student can identified the use of electromagnetic waves (such as infrared, ultraviolet, laser light, etc.) in health and industrial

2.Student can explain the differences in the use of a range of frequencies / wavelengths in the radio communications, radar, telephone, etc

Subject Material                    : The Discovery Of Electromagnetic Wave

Learning Method                  : Active Learning

Learning Model                     : Talkative, Question and Answer, Discussion

Material and Teaching Aid  : LCD, and paper to play game

Learning Activity      :

1. Opening

-          Greeting

-          Prayer

-          Checking attendance

-          Give informations about competence standard, basic competence, indicator, and learning objectives

-          Motivate students about benefit of electromagnetic wave

2. Main

Exploration    :

-          Explain about the discovery the electromagnetic wave application in everyday life

Elaboration    :

-          Give opportunity students to ask about the concept that is not understanding yet

-          Give students some exercises to do it

-          Theacher give game about the material

Confirmation :

-          Conclude the material that have discussed

3. Closing:

-          Suggest the students always study diligently

-          Closing

Evaluation:

-          Observation sheet for discussing activity

-          Observation sheet for scientific

-          Exercises and assignments

References:

1. Kanginan, Marthen.2007.Fisika untuk SMA kelas X.Jakarta:Erlangga
2. Purwoko and Fendi.2007.Fisika SMA/MA kelas X.Jakarta:Yudhistira
3. Purwoko and Fendi.2009.Physics for Senior High School Year X.Jakarta:Yudhistira

Semarang, September of 2011

Theacher,

Siti Ayu Nurmila