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Amerikalı bilim adamları, kablo kullanmadan bir cihaza enerji iletmenin yöntemini buldu. Massachusetts Teknoloji Enstitüsü'nde elektrikli cihazlara kablo kullanmadan elektrik iletebilen bir sistem geliştirildi.
Bu sistemle enerji kaynağından 2 metre uzaklıktaki 60 vatlık bir ampul kablo olmaksızın aydınlatıldı. Buluşlarını Science dergisinde yayımlayan araştırmacılar, enerjiyi, biri ampulde, diğeri enerji kaynağında bulunan iki bakır bobin arasında elektromanyetik dalgalarla iletti. Sisteme, kablosuz elektrik sözcüklerinden türetilen "WiTricity" adı verildi. WiTricity ile bir dizüstü bilgisayara gerekli enerjiden çok daha fazlasının iletilebildiğini belirten bilimadamları, bu yeni enerji iletim sisteminin özellikle geri dönüşümü sorun olan batarya probleminin çözümü için kullanılabileceğini belirtiyor. Ancak elektromanyetik dalgalarla enerji iletim yönteminin kansere yol açabileceğini savunan bazı araştırmacılar, sistemin yararlılığı konusunda endişesini dile getirdi.
Massachusetts Institute of Technology(MIT) araştırmacılarının geliştirdiği 'WiTricity', titreşim teknolojisine dayanıyor. Aynı titreşim frekansında olan iki nesne, kablo olmadan enerjilerini verimli olarak birbirlerine aktarabiliyor.
ABD'nin önde gelen üniversitelerinden Massachusetts Institute of Technology (MIT) araştırmacıları, kısa süre sonra bilgisayar ya da bir cep telefonu pilinin, enerji olmadan şarj edilebileceğini açıkladı. MIT bilimadamları, kablosuz enerji teknolojisiyle, kısa süre sonra makineleri prize bağlayan kabloları ortadan kaldıracabileceklerini veya pilleri dolu tutarak kullanıma hazır hale getirebileceklerini söyledi. MIT'de altı kişilik ekip tarafından icat edilen 'WiTricity' teknolojisi, 60 watt'lık ampule iki metre uzaktan güç verebiliyor.
TİTREŞİME DAYANIYOR: Altı kişilik araştırma takımına öncülük yapan Fizik Profesörü Marin Soljacic, bunun ortalama bir laptop için gerekli olan güç kaynağını sağlayabileceğini kaydetti. Slojacic, bu icatın önemli bir kilometre taşı olduğunu dile getirerek, teknolojinin pratik uygulamalar için kullanılabilecek noktada olduğunu vurguladı. Soljacic, teknolojinin belli oranda enerji uygulandığında bir objenin titremesine yol açan titreşim teknolojisi temeline dayandığını anlattı. Aynı titreşim frekansında olan iki nesne aynı dalga boyunda olmayan nesnelerle etkileşirken, enerjilerini verimli olarak birbirlerine aktarabiliyor. Bu konu üzerinde dört yıldır çalışan MIT Ekibinin öğrencisi Aristeidis Karalis de, bu icatın herkesi güç kablolarından kurtararak, pil değişimini en azından ev ya da ofis ortamında ideal uzunlukta tutacağını belirtti.
ŞİMDİDEN İLGİ GÖRDÜ: Ampul denemesi için MIT ekibi, elektromanyetik titreticiyi bakır sargı şeklinde kullandı. Sargılardan biri güç kaynağına iliştirildi. Diğeri ise alıcı olarak görev yaptı. Nakledici cihaz, iki metre uzaklıktaki elektromanyetik alandaki alıcıyı tarayan belli frekanstaki elektrik titreşimini yayıyor. Bu deneyde, sistem yüzde 45 verimlilikle faaliyet gösteriyor fakat araştırmacılar farklı materyaller kullanarak ve teknolojiye ayar yaparak bu oranı yüzde 70-80'e çıkarmayı umuyor.
GÜÇ KAYNAĞI AYNI: Soljacic ve ekibi, teknolojinin aynı odada, aynı güç kaynağından yararlanılması kaydıyla, laptoplar, PDA'ler (el bilgasayarları) veya cep telefonlarında kullanabilmesine kadar geliştirileceğinden eminler. Soljacic, teknolojinin çok uzun mesafede kullanılamayacağını vurgulamak için bu teknolojinin futbol sahasında çalışmayacağını belirtti. Bu deneyin ayrıntıları, haftalık Science Dergisi'nde yayınlandı. Proje, şimdiden tüketici elektroniğindeki büyük firmaların ilgisini çekti. Altı MIT araştırmacısı şimdi, bu projeyi nasıl pazarlanabilir hale getireceklerini planlıyor. Goodbye wires... CAMBRIDGE, Mass. --- Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers, and other portable electronics capable of charging themselves without ever being plugged in, freeing us from that final, ubiquitous power wire. Some of these devices might not even need their bulky batteries to operate. A team from MIT‘s Department of Physics, Department of Electrical Engineering and Computer Science, and Institute for Soldier Nanotechnologies (ISN) has experimentally demonstrated an important step toward accomplishing this vision of the future. The team members are Andre Kurs, Aristeidis Karalis, Robert Moffatt, Prof. Peter Fisher, and Prof. John Joannopoulos (Francis Wright Davis Chair and Director of ISN), led by Prof. Marin Soljačić. Realizing their recent theoretical prediction, they were able to light a 60W light-bulb from a power source seven feet (more than 2 meters) away; there was no physical connection between the source and the appliance. The MIT team refers to their concept as "WiTricity" (as in Wireless Electricity). The work will be reported in the June 7 issue of Science Express, the advance online publication of the journal Science.
The story starts one late night a few years ago, with Soljačić (pronounced Soul-ya-cheech), standing in his pajamas, staring at his cell-phone on the kitchen counter. "It was probably the sixth time that month that I was awakened by my cell-phone beeping to let me know that I had forgotten to charge it. It occurred to me that it would be so great if the thing took care of its own charging." To make this possible, one would have to have a way to transmit power wirelessly, so Soljačić started thinking which physical phenomena could help make this wish a reality.
Various methods of transmitting power wirelessly have been known for centuries. Perhaps the best known example is electromagnetic radiation, like radio waves. While such radiation is excellent for wireless transmission of information, it is not feasible to use it for power transmission. Since radiation spreads in all directions, a vast majority of power would end up being wasted into free space. One can envision using directed electromagnetic radiation, such as lasers, but this is not very practical and can be even dangerous. It requires an uninterrupted line of sight between the source and the device, as well as a sophisticated tracking mechanism when the device is mobile.
In contrast, WiTricity is based on using coupled resonant objects. Two resonant objects of the same resonant frequency tend to exchange energy efficiently, while interacting weakly with extraneous off-resonant objects. A child on a swing is a good example of this. A swing is a type of mechanical resonance, so only when the child pumps her legs at the natural frequency of the swing is she able to impart substantial energy. Another example involves acoustic resonances: imagine a room with 100 identical wine glasses, each filled with wine up to a different level, so they all have different resonant frequencies. If an opera singer sings a sufficiently loud single note inside the room, a glass of the corresponding frequency might accumulate sufficient energy to even explode, while not influencing the other glasses. In any system of coupled resonators there often exists a so-called "strongly coupled" regime of operation. If one ensures to operate in that regime in a given system, the energy transfer can be very efficient.
While these considerations are universal, applying to all kinds of resonances (e.g., acoustic, mechanical, electromagnetic, etc.), the MIT team focused on one particular type: magnetically coupled resonators. The team explored a system of two electro-magnetic resonators coupled mostly through their magnetic fields; they were able to identify the strongly coupled regime in this system, even when the distance between them was a several times larger than the sizes of the resonant objects. This way, efficient power transfer was enabled. Magnetic coupling is particularly suitable for everyday applications because most common materials interact only very weakly with magnetic fields, so interactions with extraneous environmental objects are suppressed even further. The fact that magnetic fields interact so weakly with biological organisms is also important for safety considerations," Kurs points out.
The investigated design consists of two copper coils, each a self-resonant system. One of the coils, attached to the power source, is the sending unit. Instead of irradiating the environment with electromagnetic waves, it fills the space around it with a non-radiative magnetic field oscillating at MHz frequencies. The non-radiative field mediates the power exchange with the other coil (the receiving unit) specially designed to resonate with the field. The resonant nature of the process ensures the strong interaction between the sending unit and the receiving unit, while the interaction with the rest of the environment is weak. Moffatt explains: ""The crucial advantage of using the non-radiative field lies in the fact that most of the power not picked up by the receiving coil remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost." With such a design, power transfer has a limited range, and the range would be shorter for smaller-size receivers. Still, for laptop-sized coils, power-levels more than sufficient to run a laptop can be transferred over room-sized distances nearly omni-directionally and efficiently, irrespective of the geometry of the surrounding space, even when environmental objects completely obstruct the line-of-sight between the two coils. Fisher points out: "As long as the laptop is in a room equipped with a source of such wireless power, it would charge automatically, without having to be plugged in. In fact, it would not even need a battery to operate inside of such a room." In the long run, this could reduce our society's dependence on batteries, which are currently heavy and expensive.
At first glance, such a power transfer is reminiscent of relatively commonplace magnetic induction, such as is used in power transformers, which contain coils that transmit power to each other over very short distances. An electric current running in a sending coil induces another current in a receiving coil. The two coils are very close, but they do not touch. However, this behavior changes dramatically when the distance between the coils is increased. As Karalis points out, "Here is where the magic of the resonant coupling comes about. The usual non-resonant magnetic induction would be almost 1,000,000 times less efficient in this particular system."
WiTricity is rooted in such well-known laws of physics that it makes one wonder why no one thought of it before. "In the past, there was no great demand for such a system, so people did not have a strong motivation to look into it," points out Joannopoulos, adding, "Over the past several years, portable electronic devices, such as laptops, cell-phones, iPods, and even household robots have become widespread, all of which require batteries that need to be recharged often."
As for what the future holds, Soljačić adds, "Once, when my son was about three years old, we visited his grandparents‘ house. They had a 20 year old phone and my son picked up the handset, asking, ‘Dad, why is this phone attached with a cord to the wall?‘ That is the mindset of a child growing up in a wireless world. My best response was, ‘It is strange and awkward, isn't it? Hopefully, we will be getting rid of some more wires, and also batteries, soon.‘"
This work was funded by the Army Research Office (Institute for Soldier Nanotechnologies), National Science Foundation, and the Department of Energy.
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Tanıtım
ANKARA ŞUBE
DUYURU
EMO ANKARA ŞUBESİ 26. DÖNEM YÖNETİM KURULU BAŞKANI PROF DR. ŞEREF SAĞIROĞLU`NA BİLGİSAYAR MÜHENDİSLİĞİ BÖLÜM BAŞKANLIĞINA ATANMASINDAN DOLAYI TEBRİK ZİYARETİ
