ETD Technology

ETD:  Explosives trace detector
Explosives trace detectors (ETD) are security equipment able to detect explosives of small magnitude. The detection can be done by sniffing vapors as in an explosive vapor detector or by sampling traces of particulates or by utilizing both methods depending on the scenario. Most explosive detectors in the market today can detect both vapors and particles of explosives. Devices similar to ETDs are also used to detect narcotics. The equipment is used mainly in airports and other vulnerable areas considered susceptible to acts of unlawful interference.




Current State of Passenger Explosives Trace Detection - Explosives detection for aviation security has been an area of federal concern for many years. Much effort has been focused on direct detection of explosive materials in carry-on and checked luggage, but techniques have also been developed to detect and identify residual traces that may indicate a passenger’s recent contact with explosive materials. These techniques use separation and detection technologies, such as mass spectrometry, gas chromatography, chemical luminescence, or ion mobility spectrometry, to measure the chemical properties of vapor or particulate matter collected from passengers or their carry-on luggage. Several technologies have been developed and deployed on a test or pilot basis. Parallel efforts in explosives vapor detection have employed specially trained animals, usually dogs.  The effectiveness of chemical trace analysis is highly dependent on three distinct steps:
(1)  sample collection
(2)  sample analysis, and
(3)  Comparison of results with known standards.
(4)   If any of these steps is suboptimal, the test may fail to detect explosives that are present.
When trace analysis is used for passenger screening, additional goals may include nonintrusive or minimally intrusive sample collection, fast sample analysis and identification, and low cost. While no universal solution has yet been achieved, ion mobility spectrometry is most often used in currently deployed equipment. In 2004, TSA began pilot projects to deploy portal trace detection equipment for operational testing and evaluation. In the portal approach, passengers pass through a device like a large doorframe that can collect, analyze, and identify explosive residues on the person’s body or clothing. The portal may rely on the passenger’s own body heat to volatilize traces of explosive material for detection as a vapor, or it may use puffs of air   that can dislodge small particles as an aerosol. Portal deployment is ongoing.3 one alternative to portals is to collect the chemical sample using a handheld vacuum “wand”. Another is to test an object handled by the passenger, such as a boarding pass, for residues transferred from the passenger’s hands. In this case, the secondary object is used as the carrier between the passenger and the analyzing equipment.4 the olfactory ability of dogs is sensitive enough to detect trace amounts of many compounds, but several factors have inhibited the regular use of canines for passenger screening. Dogs trained in explosives detection can generally only work for brief periods, have significant upkeep costs, are unable to communicate the identity of the detected explosives residue, and require a human handler when performing their detection role.
5. In addition, direct contact between dogs and airline passengers raises liability concerns.

Detection of Bulk Explosives. - Direct detection of explosives concealed on passengers in bulk quantities has been another area of federal interest. Technology development efforts in this area include portal systems based on techniques such as x-ray backscatter imaging, millimeter wave energy analysis, and terahertz imaging.6 As such systems detect only bulk quantities of explosives, they would not raise “nuisance alarms” on passengers who have recently handled explosives for innocuous reasons. Some versions could simultaneously detect other threats, such as nonmetallic weapons. On the other hand, trace detection techniques are also likely to detect bulk quantities of explosives and may alert screening personnel to security concerns about a passenger who has had contact with explosives but is not actually carrying an explosive device when screened. Current deployments for passenger screening are focused on trace detection, and the remainder of this report does not discuss bulk detection. However, many of the policy issues discussed below would apply similarly to bulk detection equipment.
Policy Issues-Any strategy for deploying and operating passenger explosives detection portals must consider a number of challenges. Organizational challenges include deciding where and how detectors are used, projecting costs, and developing technical and regulatory standards. Operational challenges include maximizing passenger throughput, responding to erroneous and innocuous detections, ensuring passenger acceptance of new procedures.
Equipment Location and Use. -An important component of a deployment strategy is identifying where and how passenger explosives detection equipment will be used. Portals could be deployed widely, so that all locations benefit from them, or they could be used only at selected locations, where they can most effectively address and mitigate risk. In any given location, portals could be used as a primary screening technology for all passengers, or as a secondary screening technology for selected passengers only. Widespread deployment and use for primary screening might provide more uniform risk reduction, but would require many more portals and thus increase costs.

 Cost of Operation.- The total cost of deploying explosives detection equipment for passenger screening is unknown. According to TSA, the portal systems currently being deployed in U.S. airports cost more than $160,000 each.7 Document scanning systems are somewhat less expensive; according to a 2002 GAO study, similar tabletop systems used for screening carry-on baggage can cost from $20,000 to $65,000.8 It is possible that technology improvements or bulk purchasing could lower costs. The number of devices required would depend on throughput rates, device reliability and lifetime, and deployment strategy. The United States has more than 400 commercial passenger airports; if equally distributed, several thousand devices might be required, corresponding to a total capital cost for equipment of up to hundreds of millions of dollars. Installation and maintenance costs would be additional. Operating the equipment would require additional screening procedures and might lead to costs for additional screening personnel, or else create indirect costs by increasing passenger wait times. It is unknown whether the personnel limit for TSA screeners, currently set at 45,000 full time equivalent screeners nationwide (P.L. 108-90), could accommodate the potential additional staffing requirements.

Impact on Screening Time. -When multiplied by the large number of airline passengers each day, even small increases in screening times may be logistically prohibitive. The TSA goal for passenger wait time at airports is less than 10 minutes, and screening systems reportedly operate at a rate between 7 to 10 passengers per minute;10 additional screening that slows passenger throughput and increases passenger wait time may add to airport congestion and have a detrimental economic impact. A 1996 GAO study stated that throughput goals for portal technologies at that time were equivalent to 6 passengers per minute.11 According to the same study, non-portal technologies, such as secondary object analysis, had slightly higher throughput goals. The TSA’s pilot deployment of passenger explosives trace detection equipment will likely provide useful information on passenger throughput. If no appreciable increase in screening times occurs, then passenger explosives screening may involve few additional direct economic costs beyond those of procuring, deploying, operating, and maintaining the equipment. If passenger throughput is drastically decreased, then alternatives for passenger screening may need to be considered. In between these extremes, it may be possible to moderate the economic impact by adding screening lanes or by using explosives detection equipment only on those passengers who are selected for secondary screening, as recommended by the 9/11 Commission as a possible initial step.


Erroneous and Innocuous Detection.
A potential complication of explosives trace detection is the accuracy of detector performance. False positives, false negatives, and innocuous true positives are all challenges. If the detection system often detects the presence of an explosive when there actually is none (a false positive) then there will be a high burden in verifying results through additional procedures. Because of the large volume of air passengers, even small false positive rates may be unacceptable.
Conversely, if the system fails to detect the presence of an explosive (a false negative) then the potential consequences may be serious. Assuming the system has adequate sensitivity to detect explosives traces in an operational environment, the detection threshold or criteria required for an alarm can generally be adjusted, enabling a tradeoff between false positives and false negatives, but neither can be eliminated entirely; the appropriate balance may be a matter of debate. Innocuous true positives occur when a passenger has been in contact with explosives, but for legitimate reasons. Examples include individuals who take nitroglycerin for medical purposes or individuals in the mining or construction industry who use explosives in their work. Such passengers would be regularly subject to additional security scrutiny. Similar issues arise from the current use of trace detection equipment on some airline passenger carry-on baggage, and innocuous true positives in such cases are generally handled without incident. The impact of innocuous true positives will likely depend on their frequency and on the proportion of passengers subject to explosives trace detection.

Passenger Acceptance.
 Some passengers may have personal concerns about the addition of passenger explosives trace detection to the screening process. Issues of privacy may be raised by the connection between innocuous true positives and passenger medical status or field of employment. Also, equipment that uses a vacuum “wand” or puffs of air for sample collection may offend some passengers’ sense of propriety or modesty. Passenger reluctance could then increase screening times. Allowing alternative forms of screening, such as within privacy enclosures or through different imaging technology, might mitigate passenger concerns in some cases.

Potential for Intentional Disruption.
 Another concern is the possibility that a passenger screening regimen that includes explosives trace detection could be exploited to intentionally disrupt the operation of an airport. The dissemination of trace quantities of an explosive material on commonly touched objects within the airport might lead to many positive detections on passengers. This would make trace detection less effective or ineffective for security screening, and might disrupt airport operations generally until alternative screening procedures, such as enhanced baggage screening by TSA personnel, could be put in place or the contamination source could be identified and eliminated.

Research and Development.
The DHS and its predecessor agencies have historically been the main funders of research on explosives detection for airport use. (Most of this research has focused on detecting explosives in baggage rather than on passengers.) Several other federal agencies, however, also fund research related to trace explosives detection. These include the Departments of Energy and Justice, the National Institute for Standards and Technology, and the interagency Technical Support Working Group. Much of this research has been dedicated to overcoming technical challenges, such as increasing sensitivity and reducing the time required for sample analysis. A different research challenge is the detection of novel explosives. Detectors are generally designed to look for specific explosives, both to limit the number of false or innocuous positives and to allow a determination of which explosive has been detected. As a result, novel explosives are unlikely to be detected until identifying characteristics and reference standards have been developed and incorporated into equipment designs. Unlike imaging techniques for detecting bulk quantities of explosives, trace analysis provides no opportunity for a human operator to identify a suspicious material based on
Experience or intuition. Liquid explosives are a novel threat that has been of particular interest since August 2006, when British police disrupted a plot to bomb aircraft using liquids. The DHS is evaluating technologies to detect liquid explosives.12 Its efforts are mainly focused on bulk detection, such as scanners to test the contents of bottles. Like solid explosives, however, liquids might be found through trace detection, if the trace detection system is designed to look for them.

Characteristics: 1. Sensitivity- it is defined as the lowest amount of explosive matter a detector can detect reliably. It is expressed in terms of nano grams (ng), pico-grams (pg) or femto-grams (fg) with fg being better than pg better than ng. It can also be expressed in terms of parts per billion (ppb), parts per trillion (ppt) or parts per quadrillion (ppq). Sensitivity is important because most explosives have a very low vapor pressure and give out very little vapor. The detector with the highest sensitivity will be the best in detecting vapors of explosives reliably.
2. Light weight- Portable explosive detectors need to be as light weight as possible to allow users to not fatigue when holding them. Also, light weight detectors can easily be placed on top of robots.
3. Size-Portable explosive detectors need to be as small as possible to allow for sensing of explosives in hard to reach places like under a car or an inside a trash bin.
4. Cold start up time and analysis time - The startup time should not be a parameter for evaluation of an explosive detector. Startup time only indicates the time required by the detector to reach the optimized temperature for detection of contraband substances.
Technologies used in various explosive detectors
Ion mobility spectrometry: Explosive detection using Ion mobility spectrometry (IMS) is based on velocities of ions in a uniform electric field. There are some variant to IMS such as Ion trap mobility spectrometry (ITMS) or Non-linear dependence on Ion Mobility (NLDM) which are based on IMS principle. The sensitivity of devices using this technology is limited to pg levels. The technology also requires the ionization of sample explosives which is accomplished by a radioactive source such as Nickel-63 or Americium-241. This technology is found in most commercially available explosive detectors like the GE Vapor Tracer, Smith Sabre 4000 and Russian built MO-2M and MO-8. The presence of radioactive materials in these equipment’s cause regulatory hassles and requires special permissions at customs ports. These detectors cannot be field serviced and may pose radiation hazard to the operator if the casing of the detector cracks due to mishandling. Bi-yearly checks are mandatory on such equipment in most countries by regulating agencies to ensure that there are no radiation leaks. Disposal of these equipments is also controlled owing to the high half-life of the radioactive material used. Currently there are companies entering the market with non-radioactive ionization methods for IMS for the ETD application –to overcome the limitations mentioned above. The Bruker "DE-tector" and the Implant Sciences "QS-B220" are examples of these next generation instruments. Electrospray Ionization, Mobility Analysis (DMA) and Tandem Mass Spectrometry (MS/MS) is used by SEDET (Societal Europe de Detection) for the “Air Cargo Explosive Screener (ACES)”, targeted to aviation cargo containers currently under development in Spain. "SEDET"  is a Joint Venture created by SEADM, Morpho and CARTIF in order to develop a new generation of explosive trace detection systems.
Thermo redox-This technology is based on decomposition of explosive substance followed by the reduction of the NO2 groups. Most military grade explosives have an abundance of NO2 groups on them. Explosive vapors are pulled into an adsorber at a high rate and then pyrolized. The presence of NO2 groups in the pyrolized products is then detected. This technology has significantly more false alarms because many other harmless compounds also have an abundance of NO2 groups. For example most fertilizers have NO2 groups which are falsely identified as explosives, and the sensitivity of this technology is also fairly low. A popular detector using this technology is Scientrex EVD 3000.
Chemiluminescence- This technology is based on the luminescence of certain compounds when they attach to explosive particles. This is mostly used in non-electronic equipment such as sprays and test papers. The sensitivity is pretty low in the order of ng.
Amplifying fluorescent polymer - Amplifying fluorescent polymer (AFP) is a promising new technology and is based on synthesized polymers which bind to explosive molecules and give an amplified signal upon detection. The sensitivity is in the order of fg. Explosive trace detectors based on AFP technology are produced by FLIR Systems. The current generation, Fido X3 provides broad-band trace explosive detection and weighs less than 3 lbs.
Mass Spectrometry Recently- Mass Spectrometry (MS) has emerged as another ETD technology, in products such as the Griffin 824 by FLIR Systems. Adoption of Mass Spectrometry should lower false alarms rates often associated with ETD due to the higher resolution of the core technology. Primarily used in desktop ETD systems, Mass Spectrometry can be miniaturized for handheld ETD but at the cost of compromising much of the performance that defines the technology.

Thanks.


HMI

Touch screens ? It is a human machine interface (HMI). HMI, as its name indicates, is an interface or device that allows communication between machine and its user.
/////examples of HMI?
There are various types of HMI around us. Push button is one of the simplest types of HMI. You see them on a TV remote control, on telephone set, in an elevator, and many other locations. Mouse and keyboard are more advanced types of HMI than push buttons. These types of HMI are used to interact with electronic devices with images. When a user operates a personal computer, he moves image of the cursor in the screen with mouse, and input images of characters with keyboard. A touch screen is also this type of HMI that uses images for communications between a user and electronic device. Unlike mouse and keyboard, touch screen allows a user to interact with electronic device by directly touching images displayed on the screen.

OK, I think I grasped the idea of HMI and touch screen. I have a smartphone that I operate with my fingers. As I touch its display, the images on the display change. It is a touch screen, isn't it?
Yes, exactly. But, touch screen itself is just a transparent switch that detects touched locations. How the device reacts to your touches is controlled by software. Various input devices can be made with combination use of touch screen, display and software.
What kind of input devices can be made with touch screen? Can you give me an example?
OK. For instance, a touch screen can work as a simple push button. Image of a button switch can be displayed on screen, and the device will be programmed to be on and off upon a touch on the image. If number of the button images increase, a touch screen can be used like a keyboard. Since a touch screen can detect coordinate points, it can also function as a mouse (although it does not distinguish between right and left clicks like a mouse).
I see, a touch screen can perform the same functions as other types of HMI like push button, mouse and keyboard. But, then do we need a touch screen if it performs just the same functions as other HMI? Is there any advantage to choose a touch screen over other HMI?

Doping In Semiconductors.....


Doping is the process of adding impurities in semiconductor with the intent of modulating (changing or controlling ) its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic. A semiconductor doped to such high levels that it acts more like a conductor than a semiconductor is referred to as degenerate.

Two of the most important materials silicon can be doped with, are boron (3 valence electrons = 3-valent) and phosphorus (5 valence electrons = 5-valent). Other materials are aluminum, indium (3-valent) and arsenic, antimony (5-valent).

The dopant is integrated into the lattice structure of the semiconductor crystal, the number of outer electrons define the type of doping. Elements with 3 valence electrons are used for p-type doping, 5-valued elements for n-doping. The conductivity of a deliberately contaminated silicon crystal can be increased by a factor of 10^6.

Through the introduction of a dopant with five outer electrons, in n-doped semiconductors there is an electron in the crystal which is not bound and therefore can be moved with relatively little energy into the conduction band. Thus in n-doped semiconductors one finds a donator energy level near the conduction band edge, the band gap to overcome is very small.

Analog, through introduction of a 3-valent dopant in a semiconductor, a hole is available, which may be already occupied at low-energy by an electron from the valence band of the silicon. For p-doped semiconductors one finds an acceptor energy level near the valence band.


RF Module Pin Outs..
An RF module (radio frequency module) is a (usually) small electronic device used to transmit and/or receive radio signals between two devices. In an embedded system it is often desirable to communicate with another device wirelessly. This wireless communication may be accomplished through optical communication or through Radio Frequency (RF) communication. For many applications the medium of choice is RF since it does not require line of sight. RF communications incorporate a transmitter and/or receiver.


RF modules are most often used in medium and low volume products for consumer applications such as garage door openers, wireless alarm systems, industrial remote controls, smart sensor applications, and wireless home automation systems. They are sometimes used to replace older infrared communication designs as they have the advantage of not requiring line-of-sight operation.

Several carrier frequencies are commonly used in commercially-available RF modules, including those in the industrial, scientific and medical (ISM) radio bands such as 433.92 MHz, 315 MHz, 868 MHz, 915 MHz, and 2400 MHz These frequencies are used because of national and international regulations governing the use of radio for communication.


Power Factor...
In electrical engineering, the power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load, to the apparent power in the circuit, and is a dimensionless number between -1 and 1. Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be greater than the real power. A negative power factor occurs when the device which is normally the load generates power which then flows back towards the device which is normally considered the generator.


In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.

Linear loads with low power factor (such as induction motors) can be corrected with a passive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system. In such cases, active or passive power factor correction may be used to counteract the distortion and raise the power factor. The devices for correction of the power factor may be at a central substation, spread out over a distribution system, or built into power-consuming equipment.


Save A Wet Phone.....

       How To Save A Wet Phone.....
Did your smartphone got soaked in the rain ? Or did you dropped it in the toilet or sink or some other type of liquid ?

Here is how to bring it back to life :

Switch It Off Quick :
Switch off the handset immediately. Then, quickly place it on some paper towels or soft cloth. Remove the battery, the sim, memory card and gently dry those. Essentially, remove all add-on accessories, including headphones that cover ports and slots to expose them to air.

Check Your Battery Sticker :
Handset warranties do not cover water damage. To find out if the phone is water damaged, check your battery and the battery receptacle. Manufacturers place tiny stickers that are usually white, but change to pink or red on contact with moisture inside the phones.


Wipe Your Phone Thoroughly :Wipe your device thoroughly with a soft cloth. If possible , use a small vacuum cleaner to draw the water out of the phone. Be careful not to hold the vacuum too close to the device. Do not use a hair dryer.

Keep The Phone Rice :
Place your handset in a dry plastic bag or an air-tight container with a desiccant such as silica gel (often found with new shoes and electronics). You can also purchase 5 grams sachets online and from electronic stores. Keep a stash handy this monsoon. Alternatively, bury the phone in a jar or bag of uncooked rice overnight. Rice draws out the moisture.

Blow Dry :
Air is obviously helpful, but don’t leave the gadget under the fan in an open room. Also, do not use a hair dryer on it. Hot or unpurified air isn't good for your phone. Instead, hold the wet device in front of the vent of your air conditioner for a few minutes.

Wait For 24 Hours :
Wait for at least 24 hours or longer. Check that your device ports, compartments and crevices are clean and look dry. Power up the device. If your phone does not boot, remove the battery and head to your nearest service center.

Li-Fi technology

       What is Li-Fi and How It Works....
Li-Fi, or Light Fidelity, is a technology, that can be a complement of RF communication (Wi-Fi or Cellular network), or a replacement in contexts of data broadcasting. Li-Fi, like Wi-Fi, is the high speed, bidirectional and fully networked subset of visible light communications (VLC). It is wireless and uses visible light communication (instead of radio frequency waves), that is part of the Optical Wireless Communications technologies, which carries much more information, and has been proposed as a solution to the RF-bandwidth limitations.

It is a 5G visible light communication system that uses light from light-emitting diodes (LEDs) as a medium to deliver networked, mobile, high-speed communication in a similar manner as Wi-Fi. Li-Fi could lead to the Internet of Things, which is everything electronic being connected to the internet, with the LED lights on the electronics being used as Li-Fi internet access points.[4] The Li-Fi market is projected to have a compound annual growth rate of 82% from 2013 to 2018 and to be worth over $6 billion per year by 2018.
Visible light communications (VLC) works by switching bulbs on and off within nanoseconds, which is too quickly to be noticed by the human eye. Although Li-Fi bulbs would have to be kept on to transmit data, the bulbs could be dimmed to the point that they were not visible to humans and yet still functional. The light waves cannot penetrate walls which makes a much shorter range, though more secure from hacking, relative to Wi-Fi.[8][9] Direct line of sight isn't necessary for Li-Fi to transmit signal and light reflected off of the walls can achieve 70 Mbit/s.
Li-Fi has the advantage of being able to be used in electromagnetic sensitive areas such as in aircraft cabins, hospitals and nuclear power plants [citation needed] without causing electromagnetic interference. Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi utilises radio waves, Li-Fi uses visible light. While the US Federal Communications Commission has warned of a potential spectrum crisis because Wi-Fi is close to full capacity, Li-Fi has almost no limitations on capacity.
The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum. Researchers have reached data rates of over 10 Gbit/s, which is more than 250 times faster than superfast broadband. Li-Fi is expected to be ten times cheaper than Wi-Fi. Short range, low reliability and high installation costs are the potential downsides.