Category Archives: Engineering

Carbon Nanotubes: An Allotrope Worth More than Diamonds?

Recently I read a BBC article that both confused and intrigued me. The article was about a Stanford University engineering team and their creation, the “first computer built entirely with carbon nanotubes.” (Morgan, 2013) This reminded me of graphene, a singular sheet of covalently bonded carbon atoms in hexagonal rings, that had come up in class. Remember that graphite is one of the allotropes of carbon along with diamond and the C60 fullerene and that graphene is a single layer of the carbon sheets that make up graphite. (Graphene: World-leading Research and Development, 2012) Interestingly enough, India and Vhristi have both written on graphene, and nanotubes respectively, but through wider and more introductory lens; I hope to focus my research on the application of nanotubes in electronics. Thus with this foundation, I decided to investigate further the one claim the article brought up that really fascinated me, that carbon nanotubes could eventually replace silicon chips as the linchpin of modern electronics. (Hsu, 2013)

Carbon Nanotube Arrangements
Carbon Nanotube Arrangements

Single-walled carbon nanotubes are sheets of graphene rolled up into a cylinder; depending on the direction in which the sheet is rolled, the nanotube will possess different physical properties. (Nanocyl, 2009) Extreme strength, up a hundred times stronger than steel, while maintaining lightness is one of the characteristics that have made scientists so interested in carbon nanotubes. (Bonsor & Strickland, 2007) The other is the ability to act as a semiconductor, a substance with conductivity less than that of most metals but greater than that of an insulator. (Forbus) Currently, the heart of the ubiquitous tablets, computers, and smartphones is the silicon transistor, a semiconductor switch that allow for the control of electrical signals. (Brain, 2001) To keep up with society’s demand for smaller, lighter, and faster devices, engineers have had to shrink transistors. (Hsu, 2013) However as silicon transistors get smaller, with the smallest being Intel’s 22-nanometer Ivy Bridge model, more of the energy that goes in is transformed into heat and wasted. This physical limitation has prompted research into carbon nanotubes as an alternative because of their minute size and “energy-efficiency at small sizes.” (Hsu, 2013)

So, after establishing that carbon nanotubes, theoretically, could outclass the silicon chip I went back to the BBC article to ask: what does this ‘landmark computer’ really mean for the future of carbon nanotube technology? While the computer the Stanford team, led by Subhasish Mitra and H.S. Philip Wong, created is only an elementary prototype that can only count to 32, it is definitive proof a computer could be made solely from nanotubes. (Morgan, 2013) The process in which they arrived at the computer also made great strides in use of nanotubes in electronics. The team aligned the naturally misaligned nanotubes in chips with only 0.5% disparity, designed an algorithm to bypass those that were skewed, and vaporized the “metallic” nanotubes that always conducted electricity. (Shulaker, Hills, Patil, Wei, Chen & Wong, 2013) Although these improvements have streamlined the process of creating carbon nanotube based nanoelectronics the 8000-nanometer transistors are still far from being able to compete economically or technically with silicon chips. (Palmer, 2012)

Carbon Nanotube Transistor
Carbon Nanotube Transistor

Given that silicon chips will eventually reach their limits, this test has shown that carbon nanotubes are progressing as a viable replacement for the current industry standard. (Hsu, 2013) An economic implication of this development is that if the nanotubes keep making significant progress, this possibly more efficient option to the silicon chip will be met with great demand in our technology driven society from firms and governments, the former to produce the next-generation of electronics, and the latter to improve domestic technological and military infrastructure. Just like the silicon chip allowed for a surge in technological innovation, carbon nanotubes could too engender its own rush of progress. A more short-term implication of this auspicious advancement will be reenergized investment and resources dedicated to nanotube research by firms and laboratories not wanting to be beaten to the possible patent of the next half century. But for carbon nanotubes to make the transition from laboratory to factory to store shelf will be costly and time-consuming. One must consider the economic and technological quandaries that will undoubtedly arise as this technology advances, as with all innovations. How can we mass-produce carbon nanotube transistors? How do we maintain a high quality when dealing with such tiny basic components? Each is a question that must be resolved before this new technology hits the shelves.

But I have to say, after reading about the nanotube computer I felt genuinely excited. I know that many obstacles stand in the way of carbon nanotube devices, especially the development of a cost-effective means of mass-producing nanotube transistors. On the surface this seems like a classic case of a scientifically sound theory without any means of practical execution but in this case I have hope. Ever since I have remembered I’ve been waiting for that futuristic advancement that really ushers in a new technological age like home computers and mobile phones did in the 1990s. If this it, I have hope that some combination of entrepreneurship, capitalism, and scientific curiosity will see carbon nanotube technology commercially possible, if not in our smart houses, supercomputers, and flying cars.

References:

BBC. (2011, May 04). Intel unveils 22nm 3d ivy bridge processor. Retrieved from http://www.bbc.co.uk/news/technology-13283882

Brain, M. (2001, April 25). How semiconductors work. Retrieved from http://electronics.howstuffworks.com/diode1.htm

Forbus, K. D. (n.d.). http://www.qrg.northwestern.edu/projects/vss/docs/power/3-whats-a-semiconductor.html. Retrieved from http://www.qrg.northwestern.edu/projects/vss/docs/power/3-whats-a-semiconductor.html

Hsu, J. (2013, September 26). Carbon nanotube computer hints at future beyond silicon semiconductors. Scientific American, Retrieved from http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-computer-hints-at-future-beyond-silicon

Morgan, J. (2013, September 25). First computer made of carbon nanotubes is unveiled. Retrieved from http://www.bbc.co.uk/news/science-environment-24232896

Nanocyl. (2009). Single-wall nanotubes (swnt). Retrieved from http://www.nanocyl.com/en/CNT-Expertise-Centre/Carbon-Nanotubes/Single-wall-Nanotubes-SWNT

Palmer, J. (2012, October 12). Carbon nanotubes fit by the thousands onto a chip. Retrieved from http://www.bbc.co.uk/news/science-environment-20086402

Shulaker, M. M., Hills, G., Patil, N., Wei, H., Chen, H. -., & Wong, H. -. P. (2013). Carbon nanotube computer. Nature, (501), 526-530. Retrieved from http://www.nature.com/nature/journal/v501/n7468/full/nature12502.html

(Graphene: World-leading Research and Development, 2012)The University of Manchester.(2012). Graphene is going to revolutionize the 21st Century. Retrieved 24 December, 2012, fromhttp://www.graphene.manchester.ac.uk.

Image Sources:

Groeben, N. V. D. (Photographer). (2013, September 25). Hand holding cnt wafer [Web Photo]. Retrieved from http://news.bbcimg.co.uk/media/images/70097000/jpg/_70097572_handholdingcntwafer.jpg

How Stuff Works. (Designer). (2007, October ). Nanotechnology [Web Photo]. Retrieved from http://static.ddmcdn.com/gif/nanotechnology-6.gif

Transistors or Semiconductors? The Cells of Electronics

When I first began building my computer, I learned that most computer parts only require about three different voltages, but wall sockets in the US produce 110 volts and other countries use 220 volts. That got me wondering, wouldn’t the 110 volts travel all throughout the computer? How do computer parts reduce the voltage? After getting my computer running, I researched my question for the answer: transistors. It didn’t really gave me a full understanding of how, so I decided to do more research.

If cells are the building blocks of life, transistors are the building blocks of the digital revolution. Without transistors, the technological wonders you use every day — cell phones, computers, cars — would be vastly different, if they existed at all.

Nathan Chandler at HowStuffWorks, (Chandler, n.d., p. 1)

So the guys at HowStuffWorks gave a brief overview of how transistors work. Transistors are somewhat like water faucets. In addition to starting and stopping the current, they can control how strong the current is, allowing the resulting voltage to be bigger or smaller than the original. All this is thanks a series of semiconductors, once made out of germanium is now mostly produced with silicon. Semiconductors are materials that can conduct electricity, but not very well. Naturally, Si and Ge are very weak semiconductors, conducting almost no electricity at all, but through a process called doping, the conductive properties can be changed.

Transistors from Wikipedia
Transistors from Wikipedia

Doping is the process of adding small amounts of impurities into, in this case, silicon or germanium crystal lattice. Both Ge and Si have 4 valence, the impurities usually come from either group 3 or group 5 elements, depending on the type of semiconductor desired. Having 3 valence electrons, elements such as boron and aluminum can be added to Si, creating a substance where the added impurity is missing an electron. This is called a P-type due to its positive charge from the missing electrons. Conversely, phosphorus or arsenic, elements with 5 valence electrons can be added to create N-type semiconductors due to its additional electrons giving a negative charge. A nice diagram is can be seen here in Hyperphysics.

Now equipped with both types of semiconductors, you can create a transistor by placing a series of either P-N-P or N-P-N. When applying an electrical current in the middle, “electrons will move from the N-type side to the P-type side.” Depending on the initial strength of the current and how impure the semiconductors are, the transistor will either amplify or decrease the current.

All this got me thinking on another question of mine. What other uses are there for semiconductors? The simplest use of semiconductors is diode. A diode consists of one P-type and N-type semiconductors. When put together, an electrical current can flow through from the P-type region to N-type region, but not the other way. This is because electrons can only flow from positive to negative, but not the other way around, as the N-type region will repel the moving electrons.

These can be made into Light Emitting Diodes, or LED’s, that emit a multitude of colors. Multiple semiconductors can be combined to create Random Access Memory (RAM) to increase your computer’s speed or Microprocessors for calculators and other electronic devices.

Light Emitting Diodes
Light Emitting Diodes

So to put it in perspective, just as cells build living things, transistors, according to Nathan Chandler, are the building blocks of all electronics. But seeing as semiconductors build transistors, I believe that these special compounds are the true cells in electronics. Although semiconductors have existed in electronics for quite some time, new uses and circuitry of electronics is being discovered every day.

Bibliography

Chandler, Nathan. “HowStuffWorks “How Transistors Work”.” HowStuffWorks. N.p., n.d. Web. 13 Jan. 2013. <http://electronics.howstuffworks.com/transistor.htm>.

Semiconductor Device.Wikipedia. N.p., n.d. Web. 13 Jan. 2013. <http://en.wikipedia.org/wiki/Semiconductor_device>.

The Doping of Semiconductors.Hyperphysics., n.d. Web. 13 Jan. 2013. <hyperphysics.phy-astr.gsu.edu/hbase/solids/dope.html>.

Nanotechnology: A Source of Free Energy?

Recently, I have been researching on alternative energy sources as part of a Chemistry related science club presentation. Solar panels, hydroelectric dams, wind turbines, geothermal heat pumps, were the first ideas that popped into my mind. We commonly hear about these forms of technology that are used to harness the renewable energy sources that are available to us and significant research and development have vastly improved our efficiency in utilizing these sources. However, many of these options are of larger scales and as an individual consumer, we may not have the capability or accessibility to switch towards these renewable sources even if we wanted to. Researching further into smaller scale forms of renewable energy technology, I found that innovations of all sizes are taking place, the most interesting of which is in the nascent field of nanotechnology used in harnessing solar power.

A Ted Talks by Justin Hall-Tipping, founder of a nanotechnology based energy research company called Nanoholdings, discusses some of his latest creations on how to “generate, transmit, store, and use”(Nanoholdings) solar power. Initially, he began with a common problem of the transfer of heat energy through windows in a home. The picture below illustrates how in the summer, the energy coming from the sun is heating the home that we are trying to keep cool, while in the winter, the heat is escaping from the home we are trying to keep warm.

Screen shot 2011-11-09 at 11.22.52 PM

Aiming to give consumers the ability to control the heat transfer occurring through their windows, Nanoholdings’s nanotechnology material uses Carbon, which undergoes a reaction where “graphite is blasted by a vapor, and when the vaporized Carbon condenses, it condenses back into a different form…called a Carbon nanotube”(Hall-Tipping).

Screen shot 2011-11-09 at 11.37.02 PMScreen shot 2011-11-09 at 11.37.44 PM

Vaporizing Carbon                             Structure of Carbon Nanotube

The unique thing about this nanotube is that it is “a hundred thousand times smaller than the width of one of your hairs” and “a thousand times more conductive than Copper”(Hall-Tipping). Because Carbon at the nanoscale behaves and looks very differently, instead of being black and solid, it is actually transparent and flexible. Combined with a plastic during manufacturing, this Carbon nanotube can actually undergo permanent changes in color by using merely “two volts from a millisecond pulse” (Hall-Tipping) per color change. If this material were used on a window, in its colored state, it will reflect away all heat energy from the sun, helping to insulate a cool home. Vice versa, while in its transparent state, it will allow all heat energy from the sun to pass through, helping to warm a home.

Screen shot 2011-11-09 at 11.41.19 PMScreen shot 2011-11-09 at 11.41.26 PM

Transparent Carbon Nanotube            Colored Carbon Nanotube

Another ongoing project at Nanoholdings called “NIRVision”, uses nanotechnology like above to develop “flexible, thin films…to convert infrared light into visible light”(Nanoholdings). Similar to how more modern night-vision goggles work, a “photo-detector film converts invisible infrared light into electrons…these electrons stimulate an optical film like a thin flexible display, to create a visible image”(Nanoholdings). As we know, the flow of electrons is a source of electrical energy. Hall-Tipping goes on to describe how if we combined the film created in NIRVision with the Carbon nanotube illustrated above, then we would have a material that takes “infrared radiation and converts it into electrons” (Hall-Tipping) and because of its flexibility and transparency, we would be able to attach it to any surface to ultimately become a free source of clean energy.

The applications of this nanotechnology-developed material are endless, as a free source of clean energy is the solution to both our rising energy demand and our Earth’s rising temperature. Unfortunately, this material is still being tested and until we are able to efficiently manufacture it at a low cost to the environment, we must continue our gradual movement towards renewable sources of energy and a more environmentally conscious mindset. Similar to Steven’s post on the revolutionary perspective of silk, Nanoholdings was able to take one of the most common and abundant elements, Carbon, view it from a different perspective, and alter it in a way as to develop a material with new and desired properties. An even greater implication lies in how Hall-Tipping is able to combine two different technologies with different applications and generate a new one with completely new applications. Developing brand new technology may be life changing, but sometimes the most sublime of solutions can lie in how well we can take advantage of what we already have.

Works Cited

Hall-Tipping, Justin. “Justin Hall-Tipping: Freeing Energy from the Grid | Video on TED.com.” TED: Ideas worth Spreading. TED Conferences, Oct. 2011. Web. 09 Nov. 2011. <http://www.ted.com/talks/lang/eng/justin_hall_tipping_freeing_energy_from_the_grid.html>.

Nanoholdings. “Nanoholdings – Portfolio – New Technologies – Nirvision.” Nanoholdings. Nanoholdings LLC. Web. 09 Nov. 2011. <http://nanoholdings.com/portfolio/new-technologies/nirvision>.

Mankind’s Next Giant Leap: Meet The Space Launch System

Space Shuttle Atlantis touches down at the John F. Kennedy Space Centre for the final time
Space Shuttle Atlantis touches down at the John F. Kennedy Space Center for the final time

On the 21st of July, 2011, Space Shuttle Atlantis landed, for the final time, on Runway 15 of the John F. Kennedy Space Center in Merritt Island, Florida at 5:57 am EDT (about 6:57 pm here in Shanghai). Atlantis’s landing marked both the end of its final mission, STS-135, to the International Space Station, and, on a much more significant level, the Space Shuttle program as a whole, concluding the program’s faithful service to the wider scientific community, and indeed, people the world over. As CAPCOM (capsule communicator) Barry Wilmore pointed out in his congratulatory remarks to Mission Commander Chris Ferguson, who had earlier commented that the shuttle had “earned its place in history” after “serving the world for over 30 years”, this marked the end of operations conducted by “this incredible spacecraft” which had “inspired millions around the globe”.

About two months later, on the 14th of September, NASA introduced the next major development in American spaceflight, a craft dubbed the “Space Launch System” (SLS), which was essentially a consolidation of the previously planned Ares I and IV craft into a singular craft for the use of cargo and crew. Unlike the Space Shuttle before it, the SLS is a heavy launch vehicle than an orbiter, sharing more similarities with the Saturn V launch vehicle, which helped send the Apollo Lunar Module escape the Earth’s gravitational influence on its way to the surface of the Moon, than the Space Shuttle, which saw most of its use in orbit around the Earth, as can be seen by the diagram below:

A diagram displaying the configuration of the Space Launch System
A diagram displaying the configuration of the Space Launch System

Unlike the Saturn V, however as explained by this article from NASA’s website, the SLS will serve as the launch vehicle for the Orion Multi-Purpose Crew Vehicle (MPCV), the craft that will carry astronauts and essential equipment on missions to celestial bodies beyond the distance of the Moon, with a yet-unspecified near-Earth asteroid and eventually, Mars, being marked as potential destinations. As a result of these lofty expectations, the SLS has thus been tooled to eventually be a significantly more powerful launch vehicle than the Saturn V, effectively being a bigger, badder version of the launch vehicle that helped put men on the moon. As this infographic at Space.com shows, the initial operational version of the launcher that will be commissioned for spaceflight in 2017 will be used primarily for missions in low-Earth orbit and deep space around Earth, and will already provide 0.4 million more kilograms of thrust than the Saturn V. This version of the SLS will have 3.8 million kg of thrust provided at launch by five RS-25D/E engines (modified versions of the Shuttle’s main engines) which provide power through the combustion of liquid hydrogen and liquid oxygen, and by two additional solid-fuel boosters, which are larger, longer versions of the shuttle’s boosters due to these boosters carrying more fuel (an aluminum perchlorate composite mixture) for combustion upon launch. The final operational version of the SLS will have 4.2 million kg of thrust at launch (0.8 million kg more than the Saturn V), with the further 0.4 million kg of thrust in comparison to the initial version being provided by an additional liquid-fuel (liquid hydrogen and oxygen) J-2X engine, derived from the engines used on the Saturn V itself. This final configuration, which currently does not have a defined period of operation, will be the launch vehicle used in the missions to near-Earth asteroids and Mars, the latter of which is slated to be conducted by 2030.

There are a number of implications to the development of the SLS, both to me personally and on a wider scope. In the grand scheme of things, the SLS provides the means for NASA to take the next great leap into the manned exploration of the Solar System, having the capacity to potentially take man far beyond the orbit of the Earth to places yet uncharted. The manned exploration of Mars will mark the next significant milestone in mankind’s exploration of the cosmos, as it will show that we do indeed have the capacity to visit worlds far beyond the influence of our planet and return. This will perhaps pave the way for the eventual extraterrestrial survival of the human race via the establishment of colonies on other worlds than the Earth some day, making a dream of many science-fiction fans everywhere a reality.

An artists depiction of the SLSs potential destinations
An artist's depiction of the SLS's potential destinations

On a personal level, the thought that I could actually be seeing a man set foot on Mars in person before the end of the century as a result of the SLS is a prospect that I will undoubtedly be looking forward to experiencing. While I wasn’t alive (as far as I know, anyway) to witness the Moon landing in 1969, the exhilaration, awe and indeed relief that I recall seeing on long-time CBS News Anchor Walter Cronkite’s face while watching archival footage of the landing on Youtube is an image that ingrained itself into my brain, for to me, it represents a feeling I someday hope to experience too. It was a childhood dream of mine to someday work for NASA and help with a manned mission to Mars. A dream that was fueled by many hours playing with a Lego “Mission to Mars” playset, and a dream that, due to many a struggle with the evil forces of Algebra 2/Trig, was ultimately laid to rest. While it was perhaps not my calling to work in the aeronautics industry, this childhood dream of mine instilled in me an appreciation of the stars above, and indeed, for the innovation and creativity of the men and women involved in the name of advancing the field of astronomy. I, for the past 13 or 14 years of my life, have been continually amazed by NASA and its achievements, which they have done on an approximate annual budget of around 17 billion USD as of 2007, a whopping 0.58% according to this article at The Space Review. The fact that this agency stands before us today with the potential means of sending man farther from home to other, more distant worlds in our Solar System in the name of advancing our knowledge of the cosmos and perhaps, one day ensuring the long-term survival of our race on what is essentially a pittance of an annual budget, is something that should not be understated. Take a moment and think about this, just what could NASA achieve with a higher allocation of the federal budget?

Citations:

Braukus, Michael, J.D. Harrington, and Josh Byerly. “NASA – NASA Announces Key Decision For Next Deep Space Transportation System.” National Aeronautics and Space Association, 24 May 2011. Web. 3 Nov 2011. <http://www.nasa.gov/home/hqnews/2011/may/HQ_11-164_MPCV_Decision.html>.

Brooks, Jeff. “The Space Review: Putting NASA’s budget in perspective.” The Space Review: essays and commentary about the final frontier. The Space Review, 02 Jul 2007. Web. 3 Nov 2011. <http://www.thespacereview.com/article/898/1>.

Tate, Karl. “Space Launch System: NASA’s Giant Rocket Explained (Infographic).” Space.com. N.p., 14 Sep 2011. Web. 3 Nov 2011. <http://www.space.com/12957-nasa-giant-rocket-space-launch-system-infographic.html>.

Weaver, David, Michael Braukus, J.D. Harrington, and Dan Kanigan. “NASA – NASA Announces Design for New Deep Space Exploration System.” National Aeronautics and Space Association, 14 Sep 2011. Web. 3 Nov 2011. <http://www.nasa.gov/exploration/systems/sls/sls1.html>.

Silk: A new perspective after 5000 years

While on APAC rugby, watching the discovery channel, I watched an hour-long channel on China and the Silk Road. It talked about the wonders of the silk of the silk worm, and its many different properties. Unfortunately, the silk part of the channel was brief, and left me wondering about the applications of silk. Prior to this, my only knowledge of silk was that it is is used to create clothes. A few Google searches away led me to a compelling TED talk on Silk by Fiorenzo Omenetto, who talked about the many applications of Silk, an “ancient material of the future.”
Silk is a natural protein fiber, made specifically by the refolding of water-soluble fibroins into insoluble fibers. Silk’s most unique property is being one of the strongest natural fibers, due to its chemical structure. The high proportion of glycine allows tight packing and numerous hydrogen bonds, allowing greater strength. However, silk has many more properties, such as being biodegradable, and being implantable into the human body with no immune response. These properties allow for innumerable uses for silk in our society.
The most revolutionary application of silk, however, is the reverse engineering of silk, transforming silk back into its original “ingredients” that is protein and water. One example of the application of the reverse engineering is the use of these ingredients in the creation of film, in which researchers take advantage of the fact that proteins and water reassemble and create film. This film can be further applied into nanotechnology, in which the silk solution can be poured onto the surface of a DVD player, and the silk would replicate features on even a nanoscopic level, hence retaining the information stored on the DVD. The use of this technology can also be applied to other areas of nanotechnology, such as creating optical micro prisms or even holograms.

Omenetto demonstrating silk film retaining nano-information
Omenetto demonstrating silk film retaining nano-information

Silk engineering itself holds big implications. Being biodegradable and the strongest natural fiber, it could potentially eliminate the need for plastic bags, which are detrimental to the environment. Furthermore, material such as polystyrene would be obsolete, as silk can easily be created and thrown away without guilt. Additionally, silk can be programmably degradable. Scientists can create a silk film that is programmed to not degrade in water, and create another that is, allowing scientists full control of silk’s creation and descruction. Being biocompatible, silk can be inserted into the body with no negative repercussions, giving rise to possible ideas such as silk micro needle.
The greater implication that I see, however, is the completely new perspective into a material that is 5 millennia old. This new perspective not only allows revolutionizes the way we use silk, but also begs us to start looking at other materials with new lens. While looking for new discoveries may be important, it is just as important to look at what we have right now with different perspectives, and possibly discover new applications of old materials.

Works Cited
Clark, Douglas. “Researchers Find New Uses for Silk | ChEnected | Engineers talk chemicals, bio, safety, energy, sustainability..” ChEnected | Chemical engineers discuss careers, energy, and sustainability. | AIChE. N.p., n.d. Web. 20 Oct. 2011. .
“Film Festival.” Film Festival. N.p., n.d. Web. 21 Oct. 2011. .
Lewin, Menachem. Handbook of fiber chemistry. 3rd ed. Boca Raton, FL: CRC/Taylor & Francis, 2007. Print.
Omenetto, Fiorenzo. “Fiorenzo Omenetto: Silk, the ancient material of the future | Video on TED.com.” TED: Ideas worth spreading. N.p., n.d. Web. 20 Oct. 2011. .

Radar: Luftwaffe’s Nemesis

Figure 1
Figure 1

Ever since Louis Bleriot made the first flight across the English Channel, the Britons realized that the possibility of being attacked from the air became a reality. It is this historical event that caused the Ministry of Defense to start developing an air defense system known as the “Chain Home Network”. The primitive stages of this defense network comprise of large ‘hearing blocks’ where the Royal Air Force (RAF) would have someone sit in front of the concrete blocks (above Figure 1) and listen for the sound of approaching airplane armadas. This method did produce results, however, by the time the personnel was able to hear the airplanes and relay it to command center, it was already too late for the RAF to launch an effective counter response. Hence, the Ministry of Defense decided to use another system, which they named the “object-detection system”, but little did they know that it is precisely this system that would turn the tides in favour of the Brits and change the fate of the war during the Battle for Britain. Many historians throughout the world till this day believe that the United Kingdom was key to putting Hitler’s ‘unstoppable’ Blitzkrieg (or lightning war) to a halt in Western Europe. Although what many previously did not realize is that the key component in stopping the infamous Luftwaffe during the Battle of Britain and effectively preventing the invasion of Britain was in fact an intangible system. This system had a classified name: “Radio Detecting and Ranging” object-detection system; or in today’s terms, it’s commonly known as RADAR.

Figure 2
Figure 2

I knew that the RADAR aided the British in stopping the Luftwaffe from my previous knowledge in the history of World War Two, but how did the RADAR do it?  Well, the RADAR transmits pulses of radio waves or microwaves with very long wavelength that bounces off (or reflects off) of any object in their path. Regardless of the size of the object, it returns a tiny part of the wave energy to a radar dish or antenna (shown above) that’s usually located at the same site as the transmitter. The components of RADAR are actually quite simple; it has a transmitter, a waveguide, a duplexer, a receiver, and an electronic station. The transmitter generates the radio signal with an oscillator, which emits the pulses from a radar (similar to that of a sonar sound you hear in the submarines) and the duration is controlled by a modulator (charges up with high voltage to release the pulse which is sent out through the antenna). The waveguide links the transmitter to the antenna, which broadcasts the radio signal. The duplexer is a switch between the antenna and the receiver or transmitter for the signal when the antenna is used in both situations. The radar receiver, receives the signal that is reflected off the object hit by the pulse emitted from the transmitter. This signal is then sent back to the electronic station for interpretation (commonly a visual image of that object on a circular screen showing the location of that object in Figure 3 shown below). I know this to be true because in my Phyiscs class I’ve learned that this concept of radar is valid and proven. So, by being able to detect the German bombers way before they reached Britain, the RAF was able to effectively assemble a counter-attack strike force against the bombers.

Figure 4
Figure 3
Figure 3
Figure 4

In figure 4, it shows the radar (mounted on the top of the AWAC airplane). The radar emits radios waves 360 degrees and when these radio waves ‘hit’ an object (e.g. airplane, flock of birds, etc.) the radio waves are reflected back to the airplane. The amount of time the radio waves take to travel back to the airplane is how far the object is from the radar source. This was the basic functioning of radar. The invention of radar is important then and now because if it weren’t for the development and use of RADAR in World War Two, then a lot more British civilians in London would have been killed and potentially the Luftwaffe might not have been harassed by the RAF on their bombing runs to London, and the Germans could’ve potentially invaded Britain. So, from a British military perspective, the invention of radar not only helped the RAF defend the British mainland but also aided them in bombing runs by methods of triangulation or honing in on a target to get the British bombers on track and hit their targets during blackouts at night. On the contrary however, from a German military perspective, the invention of the radar by the British became a nuisance and a great cost to the Luftwaffe. This is because they now no longer have the advantage of a surprise attack, due to the long detection ranges of the radar, and they have to defend the German cities not only from the American daylight bombing runs, but now from the British night bombing runs as well.

This knowledge and use of radar is also important to modern day times because little do we know that we actually rely on radar almost every single day. Radar has expanded its usage by being placed on airplanes and used for detecting the position of airplanes by air traffic control. Otherwise without radar and with thousands of airplanes flying over the continental US at the same time, it is very likely to crash into another airplane. Another use of radar today is to detect weather patterns and climate change, e.g. formation of a tropical storm/ hurricane, or seeing the position of storm clouds, etc. Now the technology of radar has gotten so advanced that it’s now instead of just detecting objects, radar has now been used to jam other radar in order to make an object become ‘invisible’. So, a major implication from this is that even though radar was designed intentionally for military purposes, throughout the century it has expanded into other areas. This goes to show how such a major invention in World War Two that potentially changed the tide in the Battle for Britain, has found new purposes and adapted in today’s world.

Works Cited:

Brain, Marshall. How Radar Works. HowStuffWorks. Web. 9 Oct. 2011.

How does radar and the Doppler system work?. RADARS. Web. 9 Oct. 2011.

Radar Modulator. Radar Basics. Web. 10 Oct. 2011.

Future Energy Source?

Hydrogen Fuel Cell

When I was using simple chemicals to produce electricity during my chemistry class, I had a sudden remembrance of a video that I watched during a biology class. It was based on a revolutionary technology, the hydrogen fuel cell. Ever since I watched the video, I was fascinated by hydrogen fuel cells. It seemed like an ultimate solution to the problems we face today regarding environment and energy. As a result I decided to explore deeper into the science behind the technology and evaluate its effects and

the implications. To begin with, what exactly is a fuel cell? By definition a fuel cell is “a device that produces a continuous electric current directly from the oxidation on of a fuel, as that of hydrogen by oxygen.” When looking at the definition, it can be inferred that a fuel cell doesn’t necessarily require hydrogen. But why is it that in 2003, President Bush specifically announced a program called the Hydrogen Fuel Initiative? Well hydrogen is the lightest and the most abundant chemical element, constituting around 75% of the world’s chemical elemental mass. Also hydrogen is high in energy yet when used produces almost zero pollution. In addition, the fuel cell will produce pure water that can be reused in the process. These characteristics of hydrogen make it the most ideal candidate as a fuel source for a fuel cell. Also according to DOE Hydrogen Program, “Hydrogen-powered fuel cells are not only pollution free, but also can have two to three times the efficiency of traditional combustion technologies.”

Well now that we know why hydrogen fuel cells are ideal, lets take a look at how it works. A single hydrogen fuel cell consists of an electrolyte in between anodes and cathodes with two bipolar plates on each side (connects one fuel cell to another). When hydrogen is produced through electrolysis, it is supplied to this fuel cell. When the hydrogen enters and contacts with the platinum on the catalyst, it splits into electrons and protons. The protons move across the electrolyte, also called the proton exchange membrane, and meet with oxygen that is provided from the outer environment. During this process, the electrons that were separated from the hydrogen are sent to an outer circuit where it produces electricity that is used in motor or other material. At the end of the outer circuit, the electrons meet again with the protons and oxygen. At this moment, the protons, electrons and oxygen react to form pure water. This reaction is exothermic thus produces heat at the same time. The water produced can be reused through electrolysis to supply hydrogen to the fuel cell again. If this circuit continues, then not only will the fuel cell be able to produce electricity constantly, but also fuel cells will be able to reuse the product thus saving our limited resources.

If we just consider these benefits of hydrogen fuel cell, we wonder why it hasn’t been introduced to developing countries. Well there are also negative sides of a hydrogen fuel cell. Many of the parts in a hydrogen fuel cell are costly. As a result even though the technology can be useful in the long run, it will be difficult to spread the usage of it. Also another problem is that the whole process of electrolysis requires electricity from another source for example through burning coal. This will counter the whole purpose of creating a hydrogen fuel cell. To consider all sides to this, we must also take into account the countries or even companies that rely on selling oil. For example Saudi Arabia is ranked first in the production of petroleum and second in exporting oil to the US. Although hydrogen fuel cell won’t completely replace petroleum, expansion of such technology will have a huge impact on countries like Saudi Arabia.

The implication of this technology is huge. Despite its cost, the hydrogen fuel cells can effectively reduce pollution in metropolises. As a result understanding such revolutionary technology and attempting to improve it may possibly alleviate the devastating impacts of global warming. Even when we approach this technology using ethic’s common good approach, although it may harm some countries, it will do more good than harm to our global society. Also we are living in a world with limited resources and by using a method that will produce its own fuel, we will be able to allocate our resources more efficiently. Before this research, I was only interested in hydrogen fuel cell because someone else has told me about it. But as I reached the end of this journey, I saw the huge implication behind such technology and became fascinated with it. The idea that a single technology based on simple chemistry concepts can revolutionized the world amazed me and drew me more into the magical world of science. Also, I realized that every second we are moving towards working WITH the nature to protect what we’ve been taking for granted.

Bibliography

US department of energy.” US department of energy. N.p., n.d. Web. 1 Oct 2011. Nice, Karim. “How Fuel Cells Work .” how stuff works. N.p., n.d. Web. 1 Oct 2011.

Saudi Arabia.” U.S. Energy Information Administration. n. page. Print.

With a Flick of the Wand…

The first time I saw it, I was amazed. The comforting warm that radiated from it, the welcoming hue that overflowed the room, the occasional snap that filled the silence of the night. Of course, I am speaking of fire.  And with any good fire, there is always an accompanying pale of water. Knowing that water puts out flame is one of the first things that we learn; yet the same simple principle is applied today to combat wildfires and house fires. However, this often causes water damage to the environment, not to mention the need for large amounts of water to be available. But what if there was a way to extinguish such fires with just a flick of a wand?

http://www.ericksonaircrane.com/firefighting.php
http://www.ericksonaircrane.com/firefighting.php

No, I am not speaking of Harry Potter’s magic wand. Scientists at Harvard have developed their own “wand” that can extinguish flame, using electric fields. The “wand” generates an electrical field that can suppress flames very quickly and at a distance as well. Researcher Ludovico Cademartiri demonstrated at the 241st National Meeting of American Chemical Society how such a device worked. He plugged in a 600-watt amplifier and attached the “wand” to the amplifier. With the power of 600 watts, the “wand” was able to generate an electric field of about 1 million volts per meter. While that seems like an absurd amount of energy, 1 million volts per meter is “approximately the field necessary to generate a spark in dry air”, and is therefore, not dangerous to a healthy human. The scientists proceeded to move the rod towards an open flame, about 50 centimeters tall, and almost instantly, the flame died.

A phenomenon like this deems the word “wand” almost fitting, but the concepts behind it are actually quite simple. Inside of any flame, there are electrons, Ions and soot, which all respond to electric fields. By generating a current through the “wand” an electrical field is created and like opposite sides of a magnet, the field generated by the wand repels the electrons, ions and soot inside of the fire. This resulted in the fire being, “pushed” away from its fuel source, and without fuel, the fire will die.

Of course, in real life, firefighters are faced with much larger flames, so a small wand would not be much help. However, scientists are working to increase the distance that the field affects flames, and increase the power of the field generated, so large scale fires can be combated. As this technology develops, the size of the “wand” will decrease, as will the wattage it uses. It seems that only a tenth of what Cademartiri used in his demonstration is needed to put out a that same 50 centimeter flame. Nonetheless, adapting this electrical “wand” for the use of firefighters would be very beneficial to both the economic and environmental aspects of firefighting. Advancements in the “wand” technology will allow firefighters to potentially replace their use of water to put out flames, effectively removing the issue of water damage to the building as well as their reliance of an available water source. Cademartiri also reported that the “wand” could be used to control the heat distribution of flames, so this technology would not be limited to just firefighters. Any technology that requires constant care for overheating can benefit from this technology, as the “wand” and redistribute the heat to prevent overheating.

Works Cited
Choi, Charles. “Electric Wand Makes Fire Disappear.” Daily Nature and Science News and Headlines | National Geographic News. 29 Mar. 2011. Web. 6 Apr. 2011. <http://news.nationalgeographic.com/news/2011/03/110329-electric-wands-fire-firefighters-extinguish-science-harvard-chemical/>.
Melville, Kate. “Electrical “wand” Extinguishes Fires.” Science News, Research And Discussion. 28 Mar. 2011. Web. 6 Apr. 2011. <http://www.scienceagogo.com/news/20110227210048data_trunc_sys.shtml>.

Reply to Juhi’s post: A Wall of Water.

After reading Juhi’s post about Japan’s earthquake, I decided to do a little research on Japan’s earthquake and how much it damaged Japan. I realized that the potential damage from the destruction of the nuclear plant is more devastating than the earthquake itself. This led me to ponder upon the science behind the nuclear plant and why it is so harmful to people.

Fukushima power plant after the quake
Fukushima power plant after the quake

The nuclear power plant, like other common power plants, creates electricity by operation a generator. We decide whether the power plant is hydraulic or anything else by the source of the power that operates the generator. Nuclear power plant gives power to the generator through a reaction called ‘nuclear fission’, during which a highly reactive radioactive element called enriched uranium 235 is situated at the heart of the nuclear generator. Nuclear fission is a process that causes the atoms to split into smaller pieces or components. When the Uranium undergoes nuclear fission, it splits into 25 neutrons and emits great amount of lights and energy. This energy that has been produced during the nuclear fission of the Uranium heats the water and water vapor generates the electricity. Ok, but why is this type of power plant so dangerous when it is destroyed?

nuclear power plant
nuclear power plant

One of the important parts of the reactor is a circuit pipes containing cold water that runs through the reactor. Due to the heat that has been produced by the nuclear fission, the water is heated and becomes vapor. This hot vapor needs to be cooled down after it is used to generate electricity. The circuit pipes full of cold water cool down the vapor and change it back to water. The power plant would be safe if the supply of the cool water is continued, but once condensed cooling water stops its supply of cool water to the generator, the temperature of the generator remains high, which is the basic reason for the disaster that might happen. If the cooling mechanisms fail, a power plant meltdown will occur because the enriched uranium core heats up and forms liquid. The process produces radioactive iodine and cesium. The extreme heat produced by the nuclear meltdown will also melt and burn surrounding structures inside the power plant; this can compromise structures intended to contain the radioactive fuel. When the surrounding structures are burnt, danger of massive nuclear radiation leak increases. Leak of nuclear radiation is harmful to our body and it may cause DNA mutations. Also, during a melt down, hydrogen gas is produced. When hydrogen gas reacts with the heat energy, it forms incredible amount of energy that can destroy everything. This is similar to the basic principle of the atomic bomb. Inducing from these scientific concepts, Japan itself is an atomic bomb right now.

It is impossible to count the actual number of nuclear power plant around the world, but it is certain that when a massive blackout worldwide occurs, (due to the explosion of the sunspot maybe) the entire earth will be exposed to nuclear radiation. This incident shows how our misconception that “we” have the power to control nature and use it for our own benefit can destroy us. Because it is not “we” who has power over nature, but the nature itself that owns us.

MLA Citation

Carter, Mia. “How Does a Nuclear Power Plant Work? – Japan’s Meltdown Crisis.” Suite101 (2011): n. pag. Web. 22 Mar 2011. <http://www.suite101.com/content/how-does-a-nuclear-power-plant-work—japans-meltdown-crisis-a358388>.

Hathaway, David. “The Sunspot Cycle.” National Aeronautics And Space Administration. National Aeronautics And Space Administration, 01 03 2011. Web. 22 Mar 2011. <http://solarscience.msfc.nasa.gov/SunspotCycle.shtml>.

Rogers, James. “How Do Nuclear Plants Work?.” Duke Energy n. pag. Web. 22 Mar 2011. <http://www.duke-energy.com/about-energy/generating-electricity/nuclear-how.asp>.

Reply to Ian’s Post: Shake or Stand?

After reading Ian’s blog post ‘Shake or Stand?’, I suddenly made a connection to my physics class. This is because in his post he had mentioned the words ‘natural frequency’ and coincidentally, we’re learning about waves and natural frequencies in physics. So, what is natural frequency? A frequency that’s natural? No, it is the frequencies at which an object tends to vibrate with when hit, struck, plucked, strummed, or somehow disturbed is known as the natural frequency (the Physics classroom). In simple English, it’s a frequency that causes an object to vibrate back and forth. In his post he also mentions that each building has it’s own unique natural frequency. I did a bit of research and found that the natural frequencies of vibration of a building depend on its mass and how stiff the building is. So, a taller building will have a lower natural frequency because it’s heavier and taller which makes it more flexible (IDEERS). Why is this important? It is important to determine a building’s natural frequency so then you know how the object vibrates, which in turn you can counteract that vibration by using a damper. A damper is a heavy weight that vibrates in the opposite direction of the building thus effectively canceling out any vibrations caused by the building.

The Damper that engineers use in Taipei 101 to counteract any vibrations in the building.
(Figure 1: The Damper that engineers use in Taipei 101 to counteract any vibrations in the building.)

Ian’s post mentions a building reaching it’s natural frequency potentially from vibrations from earthquakes, but a natural frequency of a building doesn’t occur just from earthquakes. It’s also possible for the natural frequency of a building to be reached from wind. As stated in the post, an earthquake causes the ground to vibrate, which in turn sends shockwaves up to the building that causes it to vibrate. The same principle applies to wind, except this time the vibrations start from the top. Wind is weaker at lower elevations because friction (e.g. mountains, hills, buildings, trees) will cause the wind to slow down, and wind is stronger at higher elevations because there is little to no friction. (Air Pressure and Wind). So the higher the building, the more susceptible it is to strong winds. Now, in the present day, engineers have revolutionized their thinking when it comes to buildings, instead of fighting against nature, why not work with nature? The Shanghai World Financial Centre (SWFC) applies this concept. At 492 meters all, the SWFC is the third tallest building in the World. At this height, it means that it is very susceptible to strong winds and it has a huge surface area at the top, which could then lead to the possibility of the building tipping over.

(Figure 2: Picture showing how the wind flows around a building.)
(Figure 2: Picture showing how the wind flows around a building.)

Think of an empty water bottle, it you blow towards the bottom of the bottle it requires a lot of strength to knock it over, however, if you blow towards the top of the water bottle, it tips over very easily. This is the same concept for a building. Which is why engineers have decided to put a big opening at the top of the SWFC, to allow the wind to flow through the building, effectively decreasing the possibility of the building tipping over and vibrating as a result from strong winds.

Figure 2: Picture of the Shanghai World Financial Center
(Figure 3: Picture of the Shanghai World Financial Center)

But wind doesn’t just affect buildings; it also affects other structures such as bridges. A famous example is the Tacoma Narrows Bridge in Washington State. On an early morning of November 7th, 1940, under strong wind conditions, the bridge began to twist and turn in a vertical motion (transverse vibration) (Wikipedia). As the wind became stronger and stronger, it caused the amplitude of the vibrations to increase because the wind was ‘putting in’ more energy then the flexing of the structure can dissipate. The Tacoma Narrows Bridge (aka Galloping Gertie) soon reached its natural frequency and snapped in half. The bridge was rebuilt and this time, the engineers were much more careful and regarded wind with the respect it deserves. A local camera store clerk recorded the collapse of the bridge on film and to this day, it serves to engineering, architecture, and physics students as a warning that nature is not to be underestimated.

Figure 3: Picture showing the collapse of the Tacoma Narrows Bridge in Washington State
(Figure 4: Picture showing the collapse of the Tacoma Narrows Bridge in Washington State)

Click here to see footage of the collapse of the Tacoma Bridge.

Click here to learn more about Resonance and Natural Frequencies.

Click here to learn more about Natural Frequencies and Simple Harmonic Motion

Works Cited:

Resistant Buildings – Vibrating – The Natural Frequency of a Building. IDEERS from Bristol University, 2008. Sun. 27 Feb. 2011.

Resonance and Standing Wave – Natural Frequency. the Physics Classroom, 2011. Sun. 27 Feb. 2011.

Tacoma Narrows Bridge (1940). Wikipedia, 2011. Sun. 27 Feb. 2011.

Wind. Air Pressure and Wind, 2003. Sun. 27 Feb. 2011.