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Mechanical Engineering

Mechanical Engineering

posted 8 months 2 weeks ago
What is a drone and how do drones work is answered here in very easy to understand language. Drone technology is constantly evolving as new innovation and big investment is bringing more advanced drones to the market every few months.
 
In this article, I will discuss UAV technology on one of the most popular drones on the market which has plenty of top drone technology.  Most drones will have very similar systems incorporated.
 
Unmanned aerial vehicle technology and science in the widest aspect covers everything from the aerodynamics of the drone, materials in the manufacture of the physical UAV, to the circuit boards, chipset and software which are the brains of the drone.
 
One of the most popular drones on the market is the Phantom 2 Vision+.  While slightly old now, it uses plenty of advanced technology and it is very popular with professional cinematographers.  This UAV is ideal to explain drone technology because it has everything in one package.  It includes the UAV, gimbal and camera and uses some of the top drone technology on the market today.
 
In only a few months since writing this article, some new and highly advanced drones such as the DJI Phantom 3, Phantom 4 and Inspire 1 have come to the market. Please read about these latest drones and innovations in our drone reviews section.
 
How Drones Work
 
A typical unmanned aircraft is made of light composite materials to reduce weight and increase maneuverability. This composite material strength allows military drones to cruise at extremely high altitudes. Drones are equipped with different state of the art technology such as infra-red cameras(military UAV), GPS and laser (military UAV). Drones can be controlled by remote control system or a ground cockpit. Drones come in a wide variety of sizes, with the large drone mostly used for military purposes such as the Predator drone, other smaller drones which can be launched by hand, to other unmanned aircraft which require short runways. An unmanned aerial vehicle system has two parts, the drone itself and the control system.  
 
The nose of the unmanned aerial vehicle is where all the sensors and navigational systems are present. The rest of the body is complete innovation since there is no loss for space to accommodate humans and also light weight. The engineering materials used to build the drone are highly complex composites which can absorb vibration which decreases the noise produced.
 
What Is A Drone – UAV Technology
 
Below we examine the science and drone technology behind the DJI Phantom 2 Vision+ UAV.  Another terrific article is a drone components overview.  This gives you a breakdown of the individual components seen in most drones.
 
Radar Positioning & Return Home
 
The flight radar displays the current position and location  of the drone in relation to the pilot.
Exceeding the control range of the remote control will trigger ‘Return-to-Home’, meaning the UAV will automatically fly back to its takeoff point and land safely.
Gyro Stabilization, IMU And Flight Controllers
 
Gyro stabilization technology is one of the components which gives the drone it’s smooth flight capabilities. The gyroscope needs to work almost instantly to the forces moving against the drone.  The gyroscope provides essential navigational information to the central flight controller.
 
The inertial measurement unit (IMU) works by detecting the current rate of acceleration using one or more accelerometers. The IMU detects changes in rotational attributes like pitch, roll and yaw using one or more gyroscopes.  Some IMU include a magnetometer to assist with calibration against orientation drift.
 
The Gyroscope is a component of the IMU and the IMU is an essential component of the drones flight controller. The flight controller is the central brain of the drone.
 
Here is a terrific article which covers gyro stabilization and IMU technology in drones.
 
Onscreen Real-Time Flight Parameters
 
Keep track of current flight telemetry and see what your drone sees on your mobile device.
 
No Fly Zone Drone Technology
 
In order to increase flight safety and prevent accidental flights in restricted areas, the new firmware for the Phantom UAV series includes a “No Fly Zone feature”.  These no fly zones have been divided into two categories: A and B.
 
GPS Ready To Fly Mode Drone Technology
 
When the compass s is calibrated, the drone then seeks the location of GPS satellites. When more than 6 are found, it allows the drone to fly in “Ready To Fly” Mode.
 
Internal Compass & Failsafe Function
 
Allows the UAV and remote control system to know exactly it’s flight location.  Calibration of the Compass is required to set a home point.  The home point is the location where the drone will return to in case of loss of signal between the drone and the remote control system.  This is also know as “fail-safe function”.
 
FPV (First Person View) Drone Technology
 
What FPV means is “First Person View” which means a video camera is mounted on the unmanned aerial vehicle and broadcasts the live video to the pilot on the ground so the pilot is flying the aircraft as if he/she was on-board the aircraft instead of looking at the craft from the pilot’s actual ground position.
 
FPV allows the unmanned aircraft to fly much higher and further than you can from the looking at the aircraft from the ground.  FPV control allows for more precise flying around obstacles especially with unmanned aerial vehicles which can easily fly indoors and through forests via FPV where you would not be able to see obstacles from a fixed position.
 
Firmware And Flight Assistant Port
 
The flight control system communicates with a PC Assistant through a Micro-USB cable. This allows configuration of the UAV and upgrade the firmware.
 
A very simple description of a drone is that it is a flying computer with a camera attached. Drones have firmware which can be updated to fix bugs and add new features.
 
LED Flight Indicators
 
These are found at the front and the rear of the drone. The front LEDs are for indicating where the nose of the drone is. The rear LEDs flight indicators light up to show the drones current flight status when the flight battery is turned on.
 
UAV Remote Control System
 
This is the wireless communication device using the 5.8 GHz frequency band. The drone and the remote control system should already be paired when it leaves the factory.
 
UAV Remote Control Receiver 
 
The location of the 5.8 GHz receiver technology link button is under the UAV.
 
Range Extender UAV Technology
 
This is a wireless communication device which operates within the 2.4 GHz frequency. It is used to extend the range of communication between the smartphone or tablet and the drone in an open unobstructed area.  Transmission distance can reach up to 700 meters. Each range extender has a unique MAC address and network name (SSID).
 
Some of the latest drones out of the box can fly using  range to a distance of up to 3.1 miles (5km).  Products such as FPV range extenders are very popular which can push the distance even further.
 
Smartphone App Featuring Ground Station Function
 
Smartphone App from Google Play or the Apple Store. The app allows for full control of the drone. There is a specific feature called ground station function on the Phantom 2 Vision+ quadcopter.  This allows for flight missions by placing location waypoints and setting waypoint altitude and overall speed.  The UAV should the be able to execute the flight mission automatically.
 
High Performance Camera
 
The Phantom 2 Vision+ carries an extremely high quality camera and a removable 4GB micro SD card. It shoots full HD video at 1080p/30 frames per second and 720p/60 frames per second, giving you crystal clear video and the option for slow motion shots.
 
The latest drones from DJI, Walkera, Yuneec and many other manufacturers now include cameras which can shoot film in 4k video and can take 12 megapixel stills.  The latest DJI Zenmuse Z3 is an integrated aerial zoom camera and is optimized for still photography.  The Zenmuse has a 7x zoom lens which is a first in aerial cameras.
 
Many of the earlier drones used cameras which were not fully suitable for aerial filming.  Many of these aerial videos had barrel distortion because of the wide angle lens.  The latest drones such as DJI Inspire 1, Phantom 3 Professional and Phantom 4 have a camera which is specifically designed for aerial filming and photography.
 
Gimbals & Tilt Control
 
The gimbal allows you to tilt the camera while in flight, creating unique angles.  It uses a 3 axial stabilized gimbal and has 2 working modes. Non-FPV mode and FPV mode.
 
Practically all the latest drones have integrated gimbals and cameras.  The leader in gimbal technology is DJI with their Zenmuse range.
 
Drones With Sensors
 
Multispectral, Lidar, Photogrammetry and Thermal sensors are now being used on drones to provide 3D models of buildings and landscape; Digital Elevation Maps (DEMS) of land, and provide precision data on the health of crops, flowers, fauna, shrubs and trees.
 
Anti-Drop Kit
 
Helps to keep the stabilizer and camera connected to the unmanned aircraft.
 
Video Editing Software
 
Having an excellent quality video software is essential for post processing. Adobe DNG raw means that all the original image information is retained for later processing. An Adobe lens profile for barrel distortion removal is available for the DJI Phantom 2 Vision+ camera.
 
Operating Systems In Drone Technology
 
Some unmanned aircraft use MS Windows operating systems.  However more and more UAV innovators are now using different versions of Linux.  The Linux Foundation recently launched the Dronecode project. The Dronecode Project is an open source, collaborative project that brings together existing and future open source unmanned aerial vehicle projects under a nonprofit structure governed by The Linux Foundation. The result will be a common, shared open source platform for Unmanned Aerial Vehicles (UAV).
 
Drones in some ways are flying computers.  With an operating system, flight controllers, main boards with programmable code, they can also be hacked into.  Like a computer, you can also protect your drone from hackers.
 
Latest Innovative Technological Drones
 
The latest advanced drones with patented technologies are the following;
 
  • DJI Phantom 4 – with “Vision” collision avoidance technology. Multi purpose drone including aerial filming, photography and photogrammetry.
  • DJI Inspire 1 – Patented design and motors.  Multi purpose drone with gimbals for professional aerial filming, photography, photogrammetry, multispectral and thermal imaging.
  • Yuneec Typhoon H Pro – uses the patented Intel “Realsense” collision avoidance technology. Great for professional aerial photography and filming
  • 3DR Solo –  multi purpose drone and can be used for professional aerial photography, filming, photogrammetry and thermal imaging.
  • Intelligent Flight Systems
All these latest drones have intelligent flight controllers and modes such as Follow Me, Active Tracking, Waypoints, Return To Home and many others.

 

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Mechanical Engineering

posted 8 months 2 weeks ago

Atomic energy has had a mixed history in the half-century or so since the world's first commercial nuclear power plant opened at Calder Hall (now Sellafield) in Cumbria, England in 1956. Huge amounts of world energy have been produced from atoms ever since, but amid enormous controversy. Some people believe nuclear power is a vital way to tackle climate change; others insist it is dirty, dangerous, uneconomic, and unnecessary. Either way, it helps if you understand what nuclear energy is and how it works—so let's forget the politics for a moment and take a closer look at the science.

What is atomic energy?

It's not immediately obvious but tall buildings store energy—potential energy. You have to work hard to lift bricks and other building materials up off the ground into the right position and, as long as they remain where you put them, they can store that energy indefinitely. But a tall, unstable building is bound to collapse sooner or later and, when it does so, the materials from which it was built come crashing back down to the ground, releasing their stored potential energy as heat, sound, and kinetic energy (the bricks could fall on your head!).
 
Atoms (the building blocks of matter) are much the same. Some large atoms are very stable and quite happy to stay as they are pretty much forever. But other atoms exist in unstable forms called radioactive isotopes. They're the atomic equivalents of wobbly old buildings: sooner or later, they're bound to fall apart, splitting into bits like a large building tumbling to the ground and releasing energy on the way. When large atoms split into one or more smaller atoms, giving off other particles and energy in the process, we call it nuclear fission. That's because the central part of the atom (the nucleus) is what breaks up and fission is another word for splitting apart. Nuclear fission can happen spontaneously, in which we case we call it radioactive decay (the conversion of unstable, radioactive isotopes into stable atoms that aren't radioactive). It can also be made to happen on demand—which is how we get energy out of atoms in nuclear power plants. That type of fission is called a nuclear reaction.
 
How much energy can one atom make?
 
A surprisingly large amount! That was what physicist Albert Einstein meant when he wrote out this simple and now famous equation:
 
E = mc2
If E is energy, m is mass (the scientific word for the ordinary stuff around us), and c is the speed of light, Einstein's equation says that you can turn a tiny amount of mass into a huge amount of energy. How come? Looking at the math, c is a really huge number (300,000,000) so c2 is even bigger: 90,000,000,000,000,000. That's how many joules (the standard measurement of energy) you'd get from a kilogram of mass. In theory, if you could turn about seven billion hydrogen atoms completely to energy, you'd get about one joule (that's about as much energy as a 10-watt lightbulb consumes in a tenth of a second). Remember, though, these are just ballpark, guesstimate numbers. The only point we really need to note is this: since there are billions and billions of atoms in even a tiny spec of matter, it should be possible to make lots of energy from not very much at all. That's the basic idea behind nuclear power.
 
In practice, nuclear power plants don't work by obliterating atoms completely; instead, they split very large atoms into smaller, more tightly bound, more stable atoms. That releases energy in the process—energy we can harness. According to a basic rule of physics called the law of conservation of energy, the energy released in a nuclear fission reaction is equal to the total mass of the original atom (and all the energy holding it together) minus the total mass of the atoms it splits into (and all the energy holding them together). For a more detailed explanation of why nuclear reactions release energy, and how much they can release, see the article binding energy on Hyperphysics.
 
What is a chain reaction?
 
What if you could make lots of atoms split up one after another? In theory, you could get them to release a huge amount of energy. If breaking up billions of atoms sounds like a real bore (like breaking billions of eggs to make an omelet), there's one more handy thing that helps: some radioactive isotopes will go on splitting themselves automatically in what's called a chain reaction, producing power for pretty much as long as you want.
 
Suppose you take a really heavy atom—a stable kind of uranium called uranium-235. Each of its atoms has a nucleus with 92 protons and 143 neutrons. Fire a neutron at uranium-235 and you turn it into uranium-236: an unstable version of the same atom (a radioactive isotope of uranium) with 92 protons and 144 neutrons (remember that you fired an extra one in). Uranium-236 is too unstable to hang around for long so it splits apart into two much smaller atoms, barium and krypton, releasing quite a lot of energy and firing off three spare neutrons at the same time.
 
Now the brilliant thing is that the spare neutrons can crash into other uranium-235 atoms, making them split apart too. And when each of those atoms splits, it too will produce spare neutrons. So a single fission of a single uranium-235 atom rapidly becomes a chain reaction—a runaway, nuclear avalanche that releases a huge amount of energy in the form of heat.
 
How does a nuclear power plant work?

Okay, we've figured how to get energy from an atom, but the energy we've got isn't that helpful: it's just a huge amount of heat! How do we turn that into something much more useful, namely electricity? A nuclear power plant works pretty much like a conventional power plant, but it produces heat energy from atoms rather than by burning coal, oil, gas, or another fuel. The heat it produces is used to boil water to make steam, which drives one or more giant steam turbines connected to generators—and those produce the electricity we're after. Here's how:

 
1) First, uranium fuel is loaded up into the reactor—a giant concrete dome that's reinforced in case it explodes. In the heart of the reactor (the core), atoms split apart and release heat energy, producing neutrons and splitting other atoms in a carefully controlled nuclear reaction.
2) Control rods made of materials such as cadmium and boron can be raised or lowered into the reactor to soak up neutrons and slow down or speed up the chain reaction.
3) Water is pumped through the reactor to collect the heat energy that the chain reaction produces. It constantly flows around a closed loop linking the reactor with a heat exchanger.
4) Inside the heat exchanger, the water from the reactor gives up its energy to cooler water flowing in another closed loop, turning it into steam. Using two unconnected loops of water and the heat exchanger helps to keep water contaminated with radioactivity safely contained in one place and well away from most of the equipment in the plant.
5) The steam from the heat exchanger is piped to a turbine. As the steam blows past the turbine's vanes, they spin around at high speed.
6) The spinning turbine is connected to an electricity generator and makes that spin too.
7) The generator produces electricity that flows out to the power grid—and to our homes, shops, offices, and factories.
 
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Mechanical Engineering

posted 8 months 2 weeks ago

What is Wave Power?

Waves are caused by the wind blowing over the surface of the ocean. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves along the shoreline. Ocean waves contain tremendous energy potential. Wave power devices extract energy from the surface motion of ocean waves or from pressure fluctuations below the surface. 

Location Where Wave Power is Used

Wave power varies considerably in different parts of the world. Areas of the world with abundant wave power resource include the western coasts of Scotland, northern Canada, southern Africa, Australia, and the northwestern coast of the United States, particularly Alaska.

Working Of Wave Power

Currently, there are three basic technological paradigms for wave energy and various companies are pursuing their own designs in these areas, said Ted Brekken, assistant professor in energy systems at Oregon State University. They are:

Oscillating body: The device, either submerged or on the surface, is moved up and down or back and forth by waves. Its motion is used to drive an electric generator. Pelamis Wave Power is developing a snake-like oscillating body that would rest on top of the water, while other devices look more like buoys.
Oscillating water column: Air enters a chamber through a hole and is compressed and decompressed by wave movement. A high-powered turbine catches the air as it's decompressed.
"Over topping device": A large structure, shore-based or in the ocean, that channels waves into a basin. When the basin's water level becomes higher than the ocean's, the basin is drained. The technology is similar to a hydropower system, in which draining water runs a turbine.
Because they'll sit in the ocean amid major storms, wave power technologies must be developed with strength in mind, Asmus said. "The key to wave power is making designs that are robust enough to withstand weather conditions," he said.
 
How effective is wave power?
 
Currently, wind is our biggest renewable energy source, Asmus said. But, he added, all ocean energy resources, including wave power, would combine to create energy 800 times more powerful than wind. According to the Department of Energy, experts believe there could be enough ocean power to provide up to two terawatts of electricity.
 
While solar energy might yield 150 watts per square meter on a sunny midday and wind power could produce 300 watts during a similar time period, wave energy has the potential to create 30,000 watts per square meter, Brekken said. "It's very power dense," he said. "That's one of the reasons why people are attracted to it."
 
Which companies are the major players in the wave power industry?
 
Experts listed these companies as among the major players:
 
Pelamis Wave Power, a Scotland-based company whose name references the Greek sea snake because of its cylindrical converter technology
Ocean Power Technologies, a New Jersey company that is installing wave farms off Oregon's coast and off Spain's northern coast
Columbia Power Technologies, through a partnership with Oregon State University, this company develops wave energy harvesting devices
Pacific Gas and Electric Company, the California utilities company that is advancing the WaveConnect program, a pilot study to test various wave energy converter devices
AWS Ocean Energy, a Scotland-based company that develops ocean energy technology
Aquamarine Power, also in Scotland, this company developed a hydroelectric wave energy converter called Oyster (and recently unveiled Oyster 2)
Oceanlinx, the Australian firm behind the oscillating water column
 
What are the benefits of wave power?
 
Because wave devices tend to be on the surface and don't have propellers, as tidal power technologies do, some believe they will create less environmental damage than other renewable energy technologies, Asmus said. Jacobson added: "There are advantages compared to wind in that the devices are smaller and don't have the visual profile that wind turbines have."
 
Also unlike wind and solar, wave energy "occurs around the clock," Jacobson said. "It's much more predictable because the waves are propagating across the oceans from long distances," he said. Wave energy reaching a wave farm can be predicted about 48 hours in advance and with increasing accuracy, he said.
 
From a business perspective, wave power provides the greatest opportunity of the ocean energies because so much of it is available, Asmus said. Once a wave farm is built, operation and maintenance costs run low because their fuel, water, is free, according to the energy department.
 
What are the downsides and challenges of wave power?
 
Wave power, like other early energy sources, is expensive, Brekken said. While coal might be priced at five to 10 cents per kilowatt hour of energy, he said, wave energy costs reach 20 to 30 cents. "The question is, "How quickly does that come down?'" Brekken said. In the United States, Asmus said, wave power companies need more research and development funds and greater subsidies. Wave energy companies need more time to develop technologies that can withstand the harsh ocean environment, Jacobson said.
 
Another thorny issue is property. Unlike building a power plant on land a company owns, the ocean is common space, Asmus said. And although some believe the environmental issues related to wave power are less so than with other technologies, there are still environmental unknowns, Jacobson said, such as how ecological systems will be affected by wave technologies and how shipping and fishing activities will be affected by device placement.
 
What's next in wave power?
 
Watch for companies to install several devices in the water over the next five years to test for failures - and spot successes, Brekken said. It's important to get prototypes out of the lab and into the water, Jacobson said, so engineers can get operations information and resource agencies can assess potential environmental effect.
 
According to the research firm Cleantech Group, venture capital investments in hydro and marine technologies jumped from $14 million in 2005 to $82 million in 2007. In 2009, however, investments sank to $27 million.

 

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Mechanical Engineering

posted 8 months 2 weeks ago

 
1) Vehicular Emission Norms:
 
The vehicular emission norms in India are detailed below:
 
(i) India notified mass emission norms for the first time during 1990-91. These norms were notified under Environment (Protection) Act (EPA) motor vehicles rules and Air Act and were applicable to vehicles at the manufacturing stage as well as for in-use vehicles.
(ii) The emission norms introduced in 1996 were very stringent and crucial.
(iii) From April 1995 only those passenger cars were allowed to be registered in four metros— Delhi; Mumbai; Kolkata and Chennai which were fitted with catalytic converter. Emission norms for such vehicles were notified under motor vehicle act in 1998.
(iv) The testing method for passenger cars was changed from hot start to cold start.
(v) More stringent norms were introduced in 2000, according to which automobile manufacturers are supposed to undergo major modifications.
(vi) As per Hon’ble Supreme Court’s directions only private vehicles conforming to at least EURO forms are being registered in NCR from June 1999 and from April 2000 only private vehicle’s conforming to Euro-II equivalent i.e., Bharat Stage-11 norms were registered. In Mumbai Euro-II norms for private vehicles (4 wheelers) was applicable from 2001.
 
In Kolkata, India – 2000 norms (Euro-I) have been made applicable from November 1999. With the acceptance of the Mashelkar Committee recommendations, passenger cars and commercial vehicles are expected ю achieve Bharat stage-II norms across the country by April 1, 2005 and Euro-Ill specifications by April 1, 2010.
 
Eleven most polluted cities had been asked to meet Bharat Stage-II norms by April 1, 2003, Euro-III norms by April 1, 2005 and Euro-IV standards by April 1, 2010. These cities are Delhi, Mumbai, Kolkata, Chennai, Bangalore, Hyderabad, Ahmedabad, Pune, Surat, Kanpur and Agra.
 
Two-wheelers and three-wheelers will have to comply with Bharat Stage-II norms by April 1, 2005 and Bharat Stage-Ill norms preferably by April 1, 2008, but not later than April 1, 2010. These schedules will, however, be reviewed in 2006, when Euro-II standards will be implemented throughout the country and Euro-III norms will be in place in the 11 most polluted cities.
 
(vii) From 1st October 1999, emission norms for agricultural tractors were introduced throughout the country. Bharat Stage-II and Bharat Stage-Ill emission norms for tractors have been scheduled to be implemented from 2003 and 2005 respectively.
 
(viii) The Bharat Stage-II norms for new 4-wheeler private non-commercial vehicle were introduced in Mumbai from January 2001 and in Kolkata and Chennai from July 2001 to 24th October, 2001.
 
(ix) Only those taxies are being registered in Delhi, which are meeting Bharat Stage-II norms.
 
(x) Bharat Stage-II norms for Diesel 4-wheeler transport vehicles were introduced in NCT from 24th October, 2001, in Greater Mumbai, Kolkata & Chennai from 31.10.2001.
 
(xi) The expert committee on Auto Oil Policy constituted in September 2001 recommended Bharat Stage-Ill emission norms for all categories of 4-wheelers in 7 mega cities from 2005 and rest of the country by 2010.
 
2) Fuel Quality Specifications:
 
Diesel and Gasoline fuel quality with respect to environment related parameters had been notified under Environment (Protection) Act during April 1996. The specifications include low leaded gasoline, unleaded gasoline and low sulphur diesel.
(i) Unleaded Gasoline:
With the progressive reduction of lead content in petrol (from 0.56 gm/1 to 0. 15 gm/1 and then to 0.013 g/1 in unleaded petrol) introduction of unleaded petrol for new passenger cars from April, 1995 and supply of only unleaded petrol for all vehicles from September, 1998, in NCT—Delhi a lethal pollutant from vehicular exhaust has been removed. The lead content in the atmosphere near traffic intersections of Delhi has reduced by more than 60% with the introduction of unleaded petrol (Table 9.10).
Table 9.10 Gasoline Lead Phase out Programme in India:
Phase Introduction date Gasoline Lead Areas covered
Phase -I June, 1994 Low leaded (0.15 g/1) Cities of Delhi, Mumbai, Kolkata and Chennai.
Phase – II 1.4.1995 Unleaded (0.013 g/1) (low leaded) Cities of Delhi, Mumbai, Kolkata and Chennai.
Phase – III 1.1.1997 Low leaded (0.15 g/1) Entire country.
Phase – IV 1.9.1998 Ban on leaded fuel only unleaded fuel) NCT – Delhi and 45 other cities.
Phase – V 31.12.1998 (Advanced to 1.9.98) Unleaded (0.013 g/1) (low leaded) All other capitals of States/UTs and other major cities.
Phase – VI 1.1.1999 Unleaded (0.013 g/1) National Capital Region.
Phase – VII 1.2.2000 Unleaded (0.013 g/1) Entire Country.
(ii) Benzene Reduction:
The fear of increased emission of benzene and reduced performance of engines by the use of unleaded petrol has also been falsified. The oil refineries were told to combine the benzene content in the unleaded petrol upto 5% (v/v) in 1996 and 3% (v/v) from the year 2000.
In addition to phasing out of lead, it is considered necessary to reduce the benzene (to 1% or lower) and aromatics in petrol not only for Delhi but also for other parts of the country. The benzene reduction programme is given in Table 9.11.
Table 9.11 Gasoline Benzene Reduction Programme:
Date of Introduction Benzene content Areas Covered
Before 1966 No specification for Benzene Entire Country
April 2000 3% Benzene Metro Cities
November 2000 1% Benzene NCT and Mumbai
2005 1% Benzene Entire Country
(iii) Sulphur in Diesel:
Sulphur content in diesel supplied in Delhi was reduced to 0.5% in 1996 and it was further reduced to 0.25% from April 1996 onward. The diesel with 0.25% sulphur has been made available throughout the country by September, 1999.
Considering the fact that several countries have introduced diesel with much lower sulphur content and it is necessary to have low sulphur diesel for meeting the emission norms beyond EURO-II norms (for EURO-I to EURO-II norms, sulphur content in diesel is 0.3%), the refineries will need to take steps for bringing down the sulphur content.
 
As per Supreme Court order (10th May 2000) single quality diesel with 0.05% sulphur to be supplied in NCT-Delhi and National Capital Region by 30th June 2001 respectively.
 
3) Lubricants Quality:
 
Specifications of 2T oil for two stroke engine with respect to smoke have been notified under EPA during September 1998 for implementation from 1.4.1999 throughout the country. Pre-mix 2T oil dispenser has been installed at all petrol filling stations in Delhi so that excessive oil is not being used by the vehicle owners. Sale of loose 2T oil has been banned from December 1998 in Delhi.
 
4) Alternate Fuels:
 
 
A very important factor in reducing vehicular pollution is the introduction of alternative fuels such as CNG and LPG.
 
(i) CNG (Compressed Natural Gas):
CNG is a better and clean fuel providing limited emissions of various toxic gases. All Government Vehicles were required to compulsorily fit CNG Kit or catalytic converter by December 1996. New CNG taxies are being registered in Delhi as well as there is no restriction or registration of CNG vehicles in National Capital Territory (NCT) as they already comply EURO-II norms. The customs duty on CNG kits has been exempted for promotion of installation of CNG kits in vehicles. Emission norms for CNG vehicles have been notified under Motor Vehicles Rules dated 24.4.2001.
(ii) LPG:
The use of LPG as an alternate fuel in automobiles has been made applicable for which amendment has been made in Motor Vehicles Act to legally permit the use of LPG as automobile fuel Hon’ble Supreme Court permitted dual mode facility (CNG + Petrol) for the vehicles in its order dated 10th May 2000. Emission norms for LPG vehicles were modified on 24.4.2001.
(iii) Battery driven vehicles:
 
Battery driven vehicles have been introduced in few corridors in Delhi.
 
5) Phase out of Grossly Polluting Vehicles:
 
 
 
(i) Registration of new auto rickshaws with conventional engine has been banned from May 1996 and registration of Defence Service and Govt. auctioned vehicles has been banned from April 1998 in Delhi.
(ii) Commercial vehicles more than 20 years old had been prohibited from plying with effect from October 1998, followed by phase out of 17 to 20 years old commercial vehicles from 15th November 1998 and 15 to 17 years old vehicles from 31st December, 1998 in Delhi.
(iii) Registration on alternation of vehicles by replacing petrol engine with diesel has been banned from 1.4.1998 in Delhi.
(iv) Registration of new private vehicles not meeting EURO-I norms has been banned from June, 1999 and vehicles not meeting EURO-II norms from April 2000 in Delhi.
 
6) Promotion of Comprehensive inspection and Certification:
 
It has been possible to reduce 30-40% pollution loads generated by vehicles through proper periodical inspection and maintenance of vehicles. Such inspection and maintenance of vehicles is being carried on by State Pollution Control Boards, Pollution Control Committees and Transport Directorates in different parts of the country.
 
7) Traffic Management:
 
 
Restriction has been imposed on goods vehicles during day time from August 1999 in Delhi.
 
(i) Left lane has been made exclusive to buses and other HMV in Delhi.
(ii) Time clocks have been installed in important red lights to enable the drivers to switch off their vehicles depending on the time left in the time clocks.
(iii)More fly-over and subways have been constructed and T-Junctions have been closed for better traffic flow.
 
8) Public Transport System:
 
(i) To discourage the use of individual motor vehicles by public, public transport system is augmented from time to time in various urban areas of the country. The number of buses has been increased in big cities like Delhi.
(ii) Private sector has been allowed to operate public transport buses to increase mobility.
(iii) Mass Rapid Transport System (MRTS) has been launched. Delhi Metro Rail Transport System is making rapid progress and is likely to reduce pressure on transport system of Delhi.
 
9) Technology:
 
 
 
(i) Fitment of catalytic converter for new petrol passenger cars has been made compulsory from 1. 4.1995 in four metros and 45 cities from 1.9.1998.
(ii) Two wheeler scooters with four stroke engines are being introduced in the market from October 1998.
(iii) Registration of only rear engine auto rickshaws is being allowed from May 1996 onwards.
(iv) More four stroke two wheelers are being registered in Delhi.
 
10) Information Dissemination/Mass Awareness:
 
(i) Messages/articles related to vehicular emissions are disseminated through newsletters, pamphlets, newspapers, magazines, Television, Radio, Internet and through Workshops, Summer Courses, Exhibitions, display, Pollution Control Camps etc.
(ii) Display of ambient air quality data through Electronic Display System near ITO intersection as well as dissemination through Newspapers, daily news and Internet.
(iii) Publishing reports related to vehicular pollution control and dissemination to various organisations.
(iv) Regular publication of air quality statistics regarding ambient air quality status in the country.
(v) Non-Government Organisations (NGOs) working in the area of Vehicular Pollution Control in different parts of the country are being encouraged for mass awareness.

 

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Mechanical Engineering

posted 8 months 2 weeks ago
 
The Energy & Environmental Research Center (EERC) is leading a series of programs that together provide the technical basis for a near-zero-emission facility. Such a facility would run more efficiently and exceed current air emission regulations. 
 
The design consists of an entire family of technologies that, when working together, will offer greatly enhanced efficiency and reduced emissions and contribute to a cleaner, healthier environment. Key components of the system include advanced coal utilization technologies to improve energy efficiency and reduce fuel use and advanced emission control devices to capture hazardous trace metals such as mercury; dramatically reduce particulate, sulfur oxide (SOx), sulfur trioxide (SO3), and nitrogen oxide (NOx); and capture carbon dioxide (CO2). 
 
Key air pollution control devices include the following. 
Mercury Control Technology
 
Through the EERC's Centers for Air Toxic Metals® program, the EERC has been proven to be the premier group in the world for developing mercury control technologies. The EERC has developed state-of-the-art, cost-effective mercury control technologies with its partners and is leading the drive to commercialize these mercury control solutions. Effective technologies now exist to remove all forms of mercury from flue gas, and the technologies can be scaled for use in virtually any site facility. 
Particulate Control Systems
 
Retrofitting power plants with the EERC's Advanced HybridTM filter technology removes more than 99.99% of fine particles from exhaust gases of coal-fired power plants, incinerators, and mineral-processing facilities as well as recaptures valuable product from process gases in the pharmaceutical and chemical industries. Particulate Test Combustor 
Wet Flue Gas Desulfurization System
The EERC's pilot-scale wet flue gas desulfurization system for sulfur control is 7 inches in diameter, with a height of approximately 20 ft. The scrubber is equipped with packing to ensure the scrubber solutions do not run down the walls of the scrubber. The column is made of plastic material, while the spray nozzles are made of stainless steel. 
Spray Dryer
 
The EERC’s spray dryer is a Niro Inc. Production MinorTM spray dryer designed to operate in conjunction with the combustion test facility (CTF). The drying chamber is 3.9 ft in diameter, with a 2.5-ft cylindrical height and a 60° conical bottom. The inner shell is constructed of 2-mm stainless steel, Type AISI 316, with a 220-grit finish. A Niro Inc. Type FS-1 rotary atomizer, capable of speeds ranging from 10,500 to 30,000 rpm, is used for atomizing lime slurry. An air disperser, supplied with the rotary atomizer, is used to introduce the properly heated (300°F [149°C]) air flow pattern throughout the chamber. The lime slurry flow rate is nominally 0.17 lb/min. 
Electrostatic Precipitator (ESP)
 
A single-wire, tubular ESP, shown schematically in the figure below, provides a specific collection area of 125 at 300°F. Gas velocity through the ESP is 5 ft/min. Plate spacing for the unit is 11 in. The ESP has an electrically isolated plate that is grounded through an ammeter, allowing continuous monitoring of the actual plate current to ensure consistent operation of the ESP. The tubular plate is suspended by a load cell and is used to monitor rapping efficiency. In addition, sight ports are located at the top of the ESP to enable online inspection of electrode alignment, sparking, rapping, and dust buildup on the plate. The ESP was designed to facilitate thorough cleaning between tests so that all tests begin on the same basis. 
Pulse-Jet Baghouse
 
The baghouse vessel is a 20-in.-inside diameter chamber that is heat-traced and insulated, with the flue gas introduced near the bottom. Three 13-ft by 5-in. bags provide an air-to-cloth ratio of 4 ft/sec. The air-to-cloth ratio can be increased by removing or adding shorter bags. A variety of bags can and have been used for tests, including 100% GORE-TEX® with a GORE-TEX membrane. These bags provide a particulate collection efficiency that is exceedingly high, >99.995%. Each bag is cleaned separately with its own diaphragm pulse valve. 
Selective Catalytic Reduction (SCR) System
 
In order to control NOx emissions from the CTF, a SCR reactor was installed ahead of the ESP. The reactor contains three catalyst layers and utilizes anhydrous ammonia as the reductant. The system is designed for a face velocity of 5 m/s and an operating temperature of 600° to 800°F, which can be controlled. Sampling ports are available at the inlet, outlet, and between the catalyst layers to facilitate gas sampling. Catalyst can be easily removed and installed to allow the use of any catalyst desired. The reactor can be quickly bypassed to accommodate specific testing needs. This reactor can also be easily moved and installed on the particulate test combustor as well. 
CO2 Capture
 
Another major focus of the EERC's program is the development of technologies to reduce CO2 emissions into the atmosphere. The EERC's Partnership for CO2 Capture is identifying and commercializing a range of CO2 capture technology systems that can be implemented into the electric utility fleet to meet environmental emission constraints and the requirements of CO2 sequestration. The technologies tested in the pilot-scale systems at the EERC included solvent scrubbing, solid sorbents, and oxygen-fired combustion. 
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