The Brazilian government recently launched an energy expansion plan to boost installed wind power generation capacity to 11.5 GW by 2020. Currently wind energy generates 1.5 GW of power for Brazil. This major increase in capacity brings huge investment opportunities for developers and entrepreneurs.
According to Jonathan Kendall, Founding partner of Rio Energy Consulting � TSS Brazil, everyone�s excited and there are hundreds of projects being planned.
Accroding to Ricardo Baitelo, Greenpeace�s renewable energy campaign coordinator in Sao Paulo, the future tenders will also be more profitable. This is because the government is poised to introduce equipment-import and other tax breaks, as well as cheaper financing rates through Brazil�s development bank BNDES, to make it all happen. Baitelo says a European-style feed-in tariff is not contemplated, however.
�The production price will go down to 200 reais (US$111) or even 100 reais (US$55) from around 300 reais (US$166) now,� once the government introduces the incentives, he adds.
According to Baitelo, the expansion is so aggressive that wind farms could very well overtake natural gas thermal plants as Brazil�s second-power generation source in five years, moving right behind the number one source � hydroelectric power.
�Right now the majority of the thermal power plants are running on natural gas, accounting for five percent of generation, though there is a small percentage of oil and diesel, accounting for four percent and coal for 1.8 percent,� Baitelo explains. �But the government doesn�t want to build more fuel-powered plants after 2015 as oil and biodiesel are more expensive to import and more polluting.�
That is why wind, as well as biomass, is expected to see huge development in coming years, observers say.
In the meantime, we�ll have a closer look at Brazil in the coming months. We at Tomorrow is Greener are really excited to see how things will progress in the South-American country.
Source : http://www.tomorrowisgreener.com/wind-power-could-become-huge-in-brazil/
Ask most Americans what geothermal energy is and you�re likely to get some quizzical looks. But in New Zealand, it would appear, the adoption and installation of geothermal systems is at an all-time high.
This information comes courtesy of New Zealand�s Minister of Energy and Resources, Gerry Brownlee, based on the June 2010 quarter energy data published in the latest edition of the Ministry of Economic Development�s New Zealand Energy Quarterly. The main use of geothermal energy in the country is for electricity generation (according to the Ministry of Economic Development�s Energy Outlook Reference Scenario, geothermal is currently the most economic option for new electricity generation in New Zealand). In 2009, electricity generation from geothermal accounted for over 10% of New Zealand�s total electricity supply, and that number is expected to increase substantially over the next 25 years.
According to the government of New Zealand, the country has easily accessible and large geothermal resources (as do many other countries with a significant landmass situated on the Pacific Rim). Currently, most of New Zealand�s installed geothermal generation capacity (about 600 megawatts) is situated in the Taupo Volcanic Zone, with another 25 MW installed at Ngawha in Northland. These installations utilize either dry steam, flash steam or binary cycle (or a combination of technologies) to create electricity, based on the temperature and conditions of particular geothermal reservoirs.
�Geothermal is a significant source of electricity generation in New Zealand, and made up over 13 per cent of total generation in the June quarter,� said Mr Brownlee, in a statement. �With a number of new geothermal projects in the pipeline, this will continue to grow.� Other highlights from this quarter�s New Zealand Energy Quarterly include the fact that renewable generation currently accounts for 73% of New Zealand�s total electricity generation, and that, in the remaining 27%, gas has now displaced coal�a combination of factors that have caused the country�s greenhouse gas emissions due to electricity generation to drop to their lowest level since 2000.
Source : http://www.tomorrowisgreener.com/geothermal-powers-new-zealand%E2%80%99s-needs/
Up to one fifth of global energy could be provided by biomass from plants without damaging food production. A new report released by UKERC suggests that. This could give some answers to the major debate which has been raging about the role biomass could play within the future energy system. While some say that biomass could play a major role in providing the world with energy, others say that it could mean an environmental disaster.
To get to the heart of the controversy, UKERC scientists at Imperial College London have undertaken a systematic review of the evidence base.
The report finds that the main reason scientists disagree is that they make different assumptions about population, diet, and land use. A particularly important bone of contention is the speed with which productivity improvements in food and energy crop production can be rolled out.
According to Dr. Raphael Slade, the report�s lead author, we can get one fifth of the current global energy supply from biomass if we make the best use of agricultural residues, energy crops and waste materials. Also he adds that this is a reasonable ambition. The report finds that getting more than this is technically possible but requires assumptions about food production and changes in diets that look increasingly challenging, especially as people in Asia and Latin America begin to adopt a high meat western diet as incomes rise.
All in all, 20% of the worlds energy supply from biomass isn�t a small number. I think achieving this goal is a fantastic way to get a 100% renewable energy world.
Source : http://www.tomorrowisgreener.com/biomass-could-produce-fifth-of-global-energy-without-damaging-food-production/
As we all know concentrated solar energy is the most commonly used renewable energy for electrical power generation. Now, a Colorado company, called Sundrop Fuels, has a new approach to the production of biofuel. The company combines the mirrors and tower of concentrated solar power with the process for the production of bio-based fuels.
Where conventional biomass-producers burn biomass for the energy needed to create biofuel, Sundrop uses concentrated solar as their energy source to gasify a range of feedstocks like agricultural waste, energy crops and wood waste. The company claims it can produce a wide range of fuels including gasoline, diesel and aviation fuel.
The company uses the high temperatures from the concentrated solar array to vaporize the biomass feedstock and form it into syngas, which is a mixture of carbon monoxide and hydrogen. The syngas forms the basic ingredient of the fuel it is turned into.
This method has more efficiencies that provide additional benefits, for example, by using the solar array, the process yields 100 to 125 gallons of fuel per ton of biomass, which is more than twice what normal biomass-producers can obtain. Next to that the process also requires far less water then other biomass systems. Only a half gallon of water is needed to produce a gallon of fuel, compared to 6 to 7 gallons required in other systems.
Sundrop expects that its process can create gasoline, without any subsidies, for less than 2 dollars per gallon. Currently the company is constructing a pilot plant and aims to have a full, commercial-scale plant of 100 million gallons operational by 2015.
Source : http://www.tomorrowisgreener.com/synthetic-gasoline-from-biomass-and-solar-power/
According to the International Hydropower Association�s (IHA) latest available figures Europe has the highest installed capacity of hydroelectric generation in the world. The report says that the EU accounts for about 260 GW of the estimated global total of 860-950 GW of hydro generation.
East-Asia has been the focus of much attention because the region is rapidly developing its hydro resources and is expected to become the region with the greatest level of deployment within the next three years. China, the biggest country in East Asia, now exceeds the United States as the country with the highest installed capacity.
Next to the rapid developments in East Asia, South America is also developing its hydroelectric generation rapidly. In addition, IHA estimates that there are 127 to 150 GW of pumped storage capacity globally, and it is anticipated that the market for pumped storage will increase by 60% over the next five years.
Large hydropower grew modestly in terms of percentage the last few years. While hydro equipment orders slipped in 2009 and 2010 from 2008, pre-orders for 2011 have risen to fuel expectations that average orders for the 2010s will top those in the 2000s, REN-21 believes.
The REN-21 report states that in 2009 a further 31 GW of hydro capacity was added which, compared to other renewable energy sources, was second only to that of wind energy. Total investment in hydropower in that year was around US$40�45 billion.
In developed markets, such as those in Europe � where many hydro plants are 30 or 40 years old � activity has focused on relicensing and repowering, as well as adding generation to existing dams, the report concludes. This trend is clearly supported by the market activity seen in 2009 and 2010, and, several markets, such as Norway, Germany, Austria and Switzerland are emerging as local hotspots.
Source : http://www.tomorrowisgreener.com/hydro-activity-in-the-last-few-years/
The largest project that began operation in 2010 also holds the record as Southeast Asia�s largest hydroelectric power station. The first of six turbines at Vietnam�s Son La station was connected to the national power grid in late December. Officials said that the two-billion-dollar plant with a capacity of 2,400 MW is expected to be fully operational in 2012, three years ahead of a target set by the National Assembly.
The second largest project that went online in 2010 took place in Laos and is that country�s largest plant in history. Laos officially inaugurated the 1,070-MW Nam Theun 2 hydroelectric power project in December. The $1.45 billion project is co-owned by Electricite de France, the Lao government, the Electricity Generating Public Co. of Thailand and Italian-Thai Development. After five years of construction, the plant began supplying neighboring Thailand with power in March of this year.
Next in line was Brazil�s 855-MW Foz do Chapeco hydropower plant, which launched commercial operations at its second of four generating unit in November 2010. The first unit began commercial operation in October. The plant is 51 percent owned by utility group CPFL Energia and sits on the border of southern states Rio Grande do Sul and Santa Catarina. Alstom supplied the turbines for this project.
Another large project that went online in 2010 is the 460-MW Beles plant in Ethiopia. The project is owned by Ethiopia Electric Power Corporation. It is worth noting that the 300 MW Tekeze Hydropower plant, which also went online in 2010 in Ethiopia, was Power Engineering�s Renewable Project of the Year.
The largest hydro project in North America that went online in 2010 was the Toba Montrose project in British Columbia. After three years of construction, Plutonic Power completed the $663 million Toba-Montrose run-of-river project, the largest source of privately generated renewable power in British Columbia. The 196-MW Toba-Montrose project began selling power to BC Hydro in August. The project includes a 73-MW run-of-river facility on Montrose Creek and a 123-MW facility on the East Toba River. The 123-MW plant on the East Toba River is the largest run-of-river facility in British Columbia.
Source : http://www.tomorrowisgreener.com/biggest-hydro-power-projects-in-2010/
Due to high oil prices and the competing demands between foods and other biofuel sources, such as palm and soybeans, due to the world�s food crisis, interest in biofuel from Algae is higher than ever before. Algae are one of the fastest growing plant species in the world. Some strains of algae can even grow so rapidly that they double in size every day, producing large amounts of lipids (oils). The compositions of these lipids are somewhat similar to petroleum molecules and scientists have figured out how to transform these lipids into biofuels.
It is said that, due the prolific ability of algae, algae can produce over 7,500 gallons of fuel per acre in a single year. Compared to soybeans, which is the main source of biodiesel in the United States, algae produces 150 times more biofuel per acre per year. If we would displace all of the petroleum that the United States uses for transportation in a single year and use biofuel from algae instead, we only need a little more than 1% of the total landmass in the United States to produce all the algae we need.
Furthermore, algae are not only quick growers, they also use carbon dioxide as a nutrient source. Another attractive characteristic of algae is that they do not affect fresh water resources, they can be produced using contaminated or ocean water and are biodegradable, which means that they are relatively harmless to the environment if something bad would happen. The ability of algae to grow almost everywhere gives producers the opportunity to grow them on marginal or desert land. This means that algae will not compete with crops for fertile soil.
Growing Algae
There are several ways to grow algae, some companies are growing algae in big open ponds others use photo-bioreactors to grow the algae under perfect conditions. The big open ponds may represent the most closely thing to nature, they are not as efficient at controlling the amount of light and nutrients that the algae must receive for optimal growth. Photobioreactors (PBR) on the other hand, are enclosed vessels that manipulate algae�s environment for maximum lipid growth. PBR�s are tubes pumped with nutrient-laden water which are exposed to sunlight. Where photo-bioreactors may have much higher yields compared to open ponds, PBR�s are a lot more expensive due to the build of acres of plastic tubes.
Another method to grow algae is fermentation. With fermentation algae are grown in dark steel drums with no access to light. All the algae get is a consistent supply of sugar. The costs of these technologies (open pond, PBR, fermentation) still need to be refined in order to become cost effective. Because the technology of extracting biofuel from algae is still in its infancy costs are expected to go down in the next coming years. As of 2008, biofuel from algae remains too expensive to replace other commercially available fuels where costs of various algae typically generate around 5 to 10 dollars per kilogram.
Future: Algae farms next to power plants
An expert team of the University of Virginia hypothesizes that when you feed algae more carbon dioxide and organic material, it could boost the lipids (oil) yield by as much as 40%. This would not suggest that biofuel from algae is carbon neutral, but it does give us the potential to cut current emission by for example placing algae farms near power plants. These power plants, such as coal power plants, produce gas which contain about 10 to 30 times as much carbon dioxide as normal air. Connecting these two together would reduce total emissions by a significant factor, eliminating the introduction of new carbon dioxide into the air.
Source : http://www.tomorrowisgreener.com/biofuel-in-the-picture-algae/
Texas may be best known for "Big Oil." But the oil that could some day make a dent in the country's use of fossil fuels is small. Microscopic, in fact: algae. Literally and figuratively, this is green fuel.
"Algae is the ultimate in renewable energy," Glen Kertz, president and CEO of Valcent Products, told CNN while conducting a tour of his algae greenhouse on the outskirts of El Paso.
Kertz, a plant physiologist and entrepreneur, holds about 20 patents. And he is psyched about the potential algae holds, both as an energy source and as a way to deal with global warming.
"We are a giant solar collecting system. We get the bulk of our energy from the sunshine," said Kertz.
Algae are among the fastest growing plants in the world, and about 50 percent of their weight is oil. That lipid oil can be used to make biodiesel for cars, trucks, and airplanes.
Most people know algae as "pond scum." And until recently, most energy research and development projects used ponds to grow it.
But instead of ponds, Valcent uses a closed, vertical system, growing the algae in long rows of moving plastic bags. The patented system is called Vertigro, a joint venture with Canadian alternative energy company Global Green Solutions. The companies have invested about $5 million in the Texas facility. "A pond has a limited amount of surface area for solar absorption," said Kertz.
"By going vertical, you can get a lot more surface area to expose cells to the sunlight. It keeps the algae hanging in the sunlight just long enough to pick up the solar energy they need to produce, to go through photosynthesis," he said. Kertz said he can produce about 100,000 gallons of algae oil a year per acre, compared to about 30 gallons per acre from corn; 50 gallons from soybeans.
Using algae as an alternative fuel is not a new idea. The U.S. Department of Energy studied it for about 18 years, from 1978 to 1996. But according to Al Darzins of the DOE's National Renewable Energy Lab, in 1996 the feds decided that algae oil could never compete economically with fossil fuels.
The price of a barrel of oil in 1996? About 20 bucks! Government scientists experimented with algae in open ponds in California, Hawaii, and in Roswell, New Mexico.
But that involved a lot of land area, with inherent problems of evaporation and contamination from other plant species and various flying and swimming critters. Darzins said NREL switched from algae research to focus on cellulosic ethanol. That's ethanol made from plants like switchgrass and plant stover -- the leaves and stalks left after a harvest -- but not edible crops such as corn and soybeans.
Valcent research scientist Aga Pinowska said there are about 65,000 known algae species, with perhaps hundreds of thousands more still to be identified. A big part of the research at the west Texas facility involves determining what type of algae produces what type of fuel. One species may be best suited for jet fuel, while the oil content of another may be more efficient for truck diesel. In the Vertigro lab, Pinowska studies the care and feeding of algae for just such specifics. She said even small changes in the nutrients that certain algae get can help create a more efficient oil content. And she said a knowledge of algae's virtues goes way back.
"Even the Aztecs knew it was beneficial; they used it as a high protein food," said Pinowska.
The other common commercial use of algae today is as a health food drink, usually sold as "Spirulina."
I'm too sexy for my pond
And who knew that single celled plants could be such "hotties" when it comes to sex? Kertz said it's a real "algae orgy" under the microscope. Some algae reproduce sexually, some asexually, while many combine both modes. In some green algae the type of reproduction may be altered if there are changes in environmental conditions, such as lack of moisture or nutrients. Intriguing details like that keep Kertz and other scientists searching for more and different algae. While dusty west Texas may not be the best hunting grounds, he said he is always on the lookout for samples in puddles, streams or ponds.
Locating algae processing plants intelligently can add to their efficiency. Locating algae facilities next to carbon producing power plants, or manufacturing plants, for instance, the plants could sequester the C02 they create and use those emissions to help grow the algae, which need the C02 for photosynthesis.
And after more than a decade hiatus, the U.S. government is back in the algae game. The 2007 Energy Security and Independence Act includes language promoting the use of algae for biofuels. From the Pentagon to Minnesota to New Zealand, both governments and private companies are exploring the use of algae to produce fuel.
But Al Darzins of the National Renewable Energy Lab said the world is still probably 5 to 10 years away from any substantial use of biofuels. "There's not any one system that anyone has chosen yet. Whatever it is has to be dirt, dirt cheap," said Darzins.
Source : http://teknologihasilperikanan-unsri.blogspot.com/search/label/Biofuel
Charles Babbage merupakan salah seorang ilmuwan di dunia, yang telah banyak memberikan karyanya pada kehidupan manusia, khususnya bidang komputer. Mesin penghitung (Difference Engine no.1) yang ditemukan oleh Charles Babbage (1791-1871) adalah salah satu icon yang paling terkenal dalam sejarah perkembangan komputer dan merupakan kalkulator otomatis pertama. Babbage juga terkenal dengan julukan bapak komputer. The Charles Babbage Foundation memakai namanya untuk menghargai kontribusinya terhadap dunia komputer. Ingin tahu lebih lanjut biografi dan karya-karyanya? Silahkan baca terus artikel ini...
Charles Babbage lahir di daerah yang sekarang dikenal dengan nama Southwark, London, 26 Desember 1791, anak dari Benjamin Babbage, seorang Banker. Kelebihannya dalam matematika sangat menonjol. Saat memasuki Trinity College di Cambridge tahun 1811, dia mendapati bahwa kemampuan matematikanya jauh lebih baik, bahkan daripada tutornya sendiri.
Di usia 20 tahunan Babbage bekerja sebagai seorang ahli matematika terutama dibidang fungsi kalkulus. Tahun 1816, dia terpilih sebagai anggota "Royal Society" (organisasi sains dan akademis independen Inggris Raya, masih aktif hingga kini) dan memainkan peran penting di yayasan "Astronomical Society" (organisasi Astronomi dan geofisika Inggris raya, masih aktif hingga kini) pada tahun 1820. Pada masa ini Babbage mulai tertarik pada mesin hitung, yang berlanjut hingga akhir hayatnya.
Tahun 1821 Babbage menciptakan Difference Engine, sebuah mesin yang dapat menyusun Tabel Matematika. Saat melengkapi mesin tersebut di tahun 1832, Babbage mendapatkan ide tentang mesin yang lebih baik, yang akan mampu menyelesaikan tidak hanya satu jenis namun berbagai jenis operasi aritmatika. Mesin ini dinamakan Analytical Engine (1856), yang dimaksudkan sebagai mesin pemanipulasi simbol umum, serta mempunyai beberapa karakteristik dari komputer modern. Diantaranya adalah penggunaan punched card, sebuah unit memori untuk memasukkan angka, dan berbagai elemen dasar komputer lainnya.
Karya Babbage kurang begitu terkenal sampai suatu saat dia bertemu dengan Ada, Countess of Lovelace, anak dari Lord Byron. Babbage mula-mula bertemu ada di sebuah acara tanggal 6 Juni 1833. Sembilan tahun kemudian, Luigi Federico Manabrea (seorang insinyur dari Italia) menjelaskan cara kerja Analytical Engine. Karya ini kemudian diterjemahkan dan ditambahkan notes oleh Ada Lovelace di tahun 1843. Mulai dari saat itu orang mulai mengenal karya Charles Babbage.
Namun sayang, hanya sedikit sisa peninggalan dari prototipe mesin Difference Engine, dikarenakan kebutuhan mesin tersebut melebihi teknologi yang tersedia pada zaman itu. Dan walaupun pekerjaan Babbage dihargai oleh berbagai institusi sains, Pemerintah Inggris menghentikan sementara pendanaan untuk Difference Engine pada tahun 1832, dan akhirnya dihentikan seluruhnya tahun 1842. Demikian pula dengan Difference Engine yang hanya terwujudkan dalam rencana dan desain.
Tahun 1828 sampai 1839, Babbage medapat gelar the Lucasian chair of mathematics (gelar professor matematika paling bergengsi di dunia) dari Universitas Cambridge. Selain mesin hitung, Babbage juga memberikan berbagai kontribusi lain. Diantaranya menciptakan sistem pos modern di Inggris, menyusun table asuransi pertama yang dapat diandalkan, menemukan locomotive cowcather (struktur berbentuk segitiga di bagian depan kereta api, yang mampu membersihkan rel dari gangguan) dan beberapa lainnya. Selain itu Babbage juga menyumbangkan ide-idenya di bidang ekonomi dan politik.
Charles Babbage juga seorang ahli cryptanalysis yang berhasil memecahkan vigenere cipher (polyalphabet cipher). Kepandaiannya ini sebetulnya sudah dimilikinya sejak tahun 1854, setelah dia berhasil mengalahkan tantangan Thwaites untuk memecahkan ciphernya. Akan tetapi penemuannya ini tidak dia terbitkan sehingga baru ketahuan di abad 20 ketika para ahli memeriksa notes-notes (tulisan, catatan) Babbage.
Dibalik seluruh keberhasilannya, kegagalan dalam pembuatan mesin perhitungan dan kegagalan bantuan pemerintah kepadanya, meninggalkan Babbage dalam kecewaan dan kesedihan di akhir masa hidupnya. Babbage meninggal di rumahnya di London pada tanggal 18 Oktober 1871.
Sumber : http://almuslim-beritateknologi.blogspot.com/2007/11/charles-babbage-sang-penemu-komputer.html
Saat ini komunikasi antar manusia makin mudah karena udah ada fasilitas telepon yang sangat membantu dalam kehidupan sehari-hari. Lalu siapa tokoh yang paling berjasa dibalik penemuan telepon? Dia adalah Alexander Graham Bell yang pertama kali menemukan alat komunikasi ini.
Bell lahir pada tanggal 3 Maret 1847 di Edinburg, Scotland. Bell berasal dari keluarga yang sangat mementingkan pendidikan. Ayahnya adalah seorang psikolog dan elocution bernama Alexander Melville Bell, sedangkan kakeknya Alexander Bell merupakan seorang elucution professor.
Setelah menyelesaikan kuliahnya di University of Edinburg dan University College di London, Bell memutuskan buat menjadi asisten ayahnya. Dia membantu orang-orang yang cacat pendengaran untuk belajar berbicara dengan metode yang telah diterapkan oleh ayahnya, yaitu dengan memperhatikan posisi bibir dan lidah lawan bicara.
Pada saat dia bermukim di London, Bell sempat belajar tentang percobaan yang dilakukan oleh Herman Ludwig von Helmholtz berupa tuning fork dan magnet yang bisa menghasilkan bunyi yang terdengar nyaring. Kemudian baru pada tahun 1865 Bell mempelajari lebih mendalam tentang suara yang keluar dari mulut saat berbicara.
Bell semakin tertarik dengan segala sesuatu yang berhubungan dengan bunyi-bunyian, makanya dia nggak keberatan ketika harus mengajar di Sarah Fuller, Boston yang merupakan sekolah khusus orang-orang tuli pada tahun 1870, selain itu Bell juga bekerja sebagai guru privat. Dan ketika dirinya diangkat menjadi guru besar psikologi di Boston University pada tahun 1873, Bell mengadakan suatu pertemuan khusus buat para guru yang menangani masalah murid-murid yang mengalami cacat pendengaran.
Hampir seluruh hidupnya Bell menghabiskan waktunya untuk mengurusi masalah pendidikan orang-orang yang cacat pendengaran bahkan kemudian dirinya mendirikan American Association to Promote the Theahing of Speech to the Deaf.
Bell mulai melakukan penelitian dengan menggunakan phonatograph, multiple telegraph dan electric speaking telegraph dari tahun 1873 sampai 1976 yang dibiayai oleh dua orang ayah dari muridnya. Salah satu penyandang dananya adalah Gardiner Hubbard yang mempunyai seorang putri yang telinganya tuli bernama Mabel, wanita inilah yang dikemudian hari menjadi istri Bell.
Di kemudian hari Bell mengungkapkan keinginannya untuk menciptakan suatu alat komunikasi dengan transmisi gelombang listrik. Bell pun mengajak temannya Thomas Watson buat membantu menyediakan perlengkapannya. Penelitiannya dilakukan dengan menggunakan alat pengatur suara dan magnet untuk menghantarkan bunyi yang akan dikirimkan, peristiwa ini terjadi pada tanggal 2 Juni 1875.
Akhirnya terciptalah karya Bell sebuah pesawat penerima telepon dan pemancar yang bentuknya berupa sebuah piringan hitam tipis yang dipasang di depan electromagnet. Baru pada tanggal 14 Februari 1876 Bell mematenkan hasil penemuannya, tapi oleh US Patent Office penemuan Bell ini baru resmi dipatenkan pada tanggal 7 Maret untuk �electric speaking telephone�.
Bell terus memperbarui penemuannya dan untuk pertama kalinya dia berhasil mengirimkan suatu kalimat berbunyi �Watson, come here, I want you� pada tanggal 10 Maret 1876.
Sumber : http://members.tripod.com/perkembangan_telepon/sejarah.htm
Lampu pijar adalah sumber cahaya buatan yang dihasilkan melalui penyaluran arus listrik melalui filamen yang kemudian memanas dan menghasilkan cahaya. Kaca yang menyelubungi filamen panas tersebut menghalangi udara untuk berhubungan dengannya sehingga filamen tidak akan langsung rusak akibat teroksidasi.
Lampu pijar dipasarkan dalam berbagai macam bentuk dan tersedia untuk tegangan (voltase) kerja yang bervariasi dari mulai 1,25 volt hingga 300 volt. Energi listrik yang diperlukan lampu pijar untuk menghasilkan cahaya yang terang lebih besar dibandingkan dengan sumber cahaya buatan lainnya seperti lampu pendar dan dioda cahaya, maka secara bertahap pada beberapa negara peredaran lampu pijar mulai dibatasi.
Di samping memanfaatkan cahaya yang dihasilkan, beberapa penggunaan lampu pijar lebih memanfaatkan panas yang dihasilkan, contohnya adalah pemanas kandang ayam, dan pemanas inframerah dalam proses pemanasan di bidang industri.
Sejarah lampu Pijar dan Penemu Pertama
Edison mematenkan penemuannya pada 1879. Ide lampu sebenarnya sudah berusia 70 tahun sebelum Edison mematenkannya. Sir Humpry Davy adalah orang pertama yang mendemonstrasikan dua batang karbon yang memercikkan cahaya. Hanya saja, cahaya yang dihasilkan terlalu terang, seperti percikan cahaya saat mengelas besi. Selain itu, lampu ini membutuhkan sumber listrik yang terlalu besar. Lampu Davy masih bisa Anda lihat saat ini di konser musik atau pembukaan toko baru yang meriah.
Kompetisi Menemukan Lampu
Banyak ilmuwan tertarik pada penemuan Davy. Mereka berusaha memecah cahaya yang terlalu terang itu. Salah satu caranya adalah dengan mengalirkannya melalui suatu material. Hanya saja, material tersebut akan termakan oleh listrik yang berpijar. Untuk mengatasinya maka perlu membatasi kontak antara listrik pijar dengan oksigen. Di situlah muncul ide untuk mengurungnya dalam bola.
Pada 1841, Frederick DeMoleyns mematenkan bohlam yang terbuat dari campuran platina dan karbon. Empat tahun berikutnya, J.W. Starr mematenkan bohlam vakum dengan bahan pembakar karbon. Kemudian, banyak orang berusaha memvakum bohlam menggunakan material lain, kadang dengan bentuk yang berbeda. Penemuan mereka berhasil di laboratorium tetapi tidak bisa digunakan dalam kehidupan sehari-hari.
Pada 1878, Thomas Alva Edison bergabung dalam kompetisi pembuatan bohlam yang efektif dan efisien. Sebelumnya, Edison sudah terkenal sebagai penemu telegraf dan fonograf. Pada Oktober, dia mengumumkan bahwa dia sudah mampu mengatasi permasalahan bohlam.
Pengumuman itu terlalu dini, Edison memang sudah punya gagasannya, tetapi dia belum sempat menyempurnakannya. Bicara memang lebih mudah ketimbang melakukannya. Itulah yang terjadi. Dalam usaha menyempurnakan gagasannya, Edison gagal terus.
Francis Upton
Edison mengajak Francis Upton, dari Universitas Princeton, bergabung dalam penelitiannya. Mereka mulai mendaftar percobaan gagal yang dilakukan orang lain dan menghindari cara-cara tersebut. Mereka juga mendaftar sifat-sifat material yang telah digunakan dan mencari material yang tepat. Mereka menemukan bahwa pembakar yang tepat adalah material yang memiliki hambatan besar. Material dengan hambatan besar tidak menghabiskan banyak listrik. Mereka mulai menyeleksi semua material yang memiliki hambatan besar.
Bohlam Pertama
Pada Oktober 1879, setahun setelah pengumuman gagasannya, Edison menggunakan kapas yang dikarbonasi sebagai pembakar. Lampu itu menyala, tetapi hanya mampu bertahan 13 jam. Itulah lampu yang diklaim sebagai bohlam pertama.
Dalam pengembangannya, Edison menemukan bahwa bambu Jepang yang dikarbonasi merupakan material yang paling tepat sebagai pembakar. Material ini kemudian dikenal sebagai filamen. Bohlam yang menggunakan filamen bertahan sampai 600 jam.
Jawaban "Thomas Alva Edison" sebagai penemu bohlam tidak sepenuhnya tepat karena sudah banyak orang yang menemukan bohlam. Hanya saja, Edison menemukan bohlam yang bisa digunakan dalam kehidupan sehari-hari dengan konsumsi listrik yang efisien.
Sumber: pandri-16.blogspot.com
Sejarah awal ditemukannya listrik adalah oleh seorang cendikiawan Yunani yang bernama Thales, yang mengemungkakan fenomena batu ambar yang bila digosok - gosokkan akan dapat menarik bulu sebagai fenomena listrik. Kemudian setelah bertahun - tahun semenjak ide Thales dikemukakan, baru kemudian muncul lagi penapat - pendapat serta teori -teori baru mengenai listrik seperti yang diteliti dan dikemukakan oleh William Gilbert, Joseph priestley, Charles De Coulomb, AmpereMichael Farraday, Oersted, dll.
Sejarah Listrik
Dalam hal kelistrikan, memang banyak tokoh yang telah berpartisipasi. Sebut saja de Coulomb, Alesandro Volta, Hans C. Cersted, dan Andre Marie Ampere. Mereka ini dianggap "jago-jago" terbaik di bidang listrik. Namun, dari semua itu, orang tak boleh melupakan satu nama yang sangat berjasa dan dikenal sebagai perintis dalam meneliti tentang listrik dan magnet. Dialah Michael Faraday, seorang ilmuwan asal Inggris.
Michael Faraday lahir pada tanggal 22 September 1791 di Newington Butts, Inggris. Orang tuanya tergolong keluarga miskin. Ayahnya hanya seorang tukang besi yang harus memberi makan sepuluh anaknya. Tak heran jika ayahnya tak mampu membiayai sekolah anak-anaknya tak terkecuali dengan Faraday. Untuk membantu ekonomi keluarga, pada usia 14 tahun Faraday bekerja sebagai penjilid buku sekaligus penjual buku. Di sela-sela pekerjaannya ia manfaatkan untuk membaca berbagai jenis buku, terutama ilmu pengetahuan alam, fisika, dan kimia.
Ketika umurnya menginjak 20 tahun, dia mengikuti ceramah-ceramah yang diberikan oleh ilmuwan Inggris kenamaan. Salah satunya adalah Sir Humphry Davy, seorang ahli kimia yang juga kepala laboratorium Royal Institution. Selama mengikuti ceramah, Faraday membuat catatan dengan teliti dan menyalinnya kembali dengan rapi apa yang didengarnya. Kemudian, berkas catatan itu ia kirimkan kepada Humphry Davy disertai lamaran kerja. Ternyata sang dosen tertarik dan mengangkat Faraday sebagai asistennya di Laboratorium Universitas terkenal di London. Saat itu dia berusia 21 tahun.
Di bawah bimbingan Davy, Faraday menunjukkan kemajuan pesat. Awalnya, ia hanya bekerja sebagai seorang pencuci botol. Tetapi, berkat kegigihannya dalam belajar, hanya dalam waktu relatif singkat, ia dapat membuat penemuan-penemuan baru atas hasil kreasinya sendiri, yaitu menemukan dua senyawa klorokarbon dan berhasil mencairkan gas klorin dan beberapa gas lainnya. Berkat kepandainnya pula, Faraday dapat berhubungan dengan para ahli ternama, seperti Andre Marie Ampere. Di samping itu, ia juga mendapat kesempatan berkeliling Eropa bersama Davy. Pada kesempatan itu, Faraday mulai membangun pengetahuannya yang praktis dan teoretis.
Davy memiliki pengaruh besar dalam pemikiran Faraday dan telah mengantarkan Faraday pada penemuan-penemuannya. Penemuan Faraday pertama yang penting di bidang listrik terjadi tahun 1821. Dua tahun sebelumnya Oersted telah menemukan bahwa jarum magnet kompas biasa dapat beringsut jika arus listrik dialirkan dalam kawat yang tidak berjauhan. Dari temuan ini, Faraday berkesimpulan, jika magnet diketatkan, yang bergerak justru kawatnya. Bekerja atas dasar dugaan ini, dia berhasil membuat suatu skema yang jelas di mana kawat akan terus-menerus berputar berdekatan dengan magnet sepanjang arus listrik dialirkan ke kawat.
Sesungguhnya, dalam hal ini Faraday sudah menemukan motor listrik pertama, suatu skema pertama penggunaan arus listrik untuk membuat sesuatu benda bergerak. Betapa pun primitifnya, penemuan Faraday ini merupakan "nenek moyang" dari semua motor listrik yang digunakan dunia sekarang ini. Sejak penemuannya yang pertama pada tahun 1821, Michael Faraday si ilmuwan autodidak ini namanya mulai terkenal. Hasil penemuannya dianggap sebagai pembuka jalan dalam bidang kelistrikan.
Hukum Faraday
Dalam percobaan-percobaan yang dilakukannya pada tahun 1831, ia menemukan bahwa bila magnet dilalui sepotong kawat, arus akan mengalir di kawat, sedangkan magnet bergerak. Keadaan ini disebut "pengaruh elektromagnetik" dan penemuan ini disebut "Hukum Faraday". Penemuan ini dianggap sebagai penemuan monumental. Mengapa? Pertama, "Hukum Faraday" memiliki arti penting dalam hubungan dengan pengertian teoretis kita tentang elektromagnetik. Kedua, elektromagnetik dapat dipergunakan sebagai penggerak secara terus-menerus arus aliran listrik seperti yang digunakan oleh Faraday dalam pembuatan dinamo listrik pertama.
Dengan berbagai temuannya, tak berlebihan jika Faraday termasuk salah satu tokoh yang telah memberi sumbangan terbesar pada umat manusia. Ia seorang yang sederhana, seorang penemu yang mulai belajar secara autodidak. Kesederhanaannya ia tunjukkan ketika dia menolak diberi gelar kebangsawanan dan juga menolak jadi ketua British Royal Society. Karena masalah kesehatan, Michael Faraday berhenti meneliti. Tetapi, ia meneruskan pekerjaannya sebagai dosen sampai 1861. Ia meninggal dunia pada tanggal 25 Agustus 1867 dan dimakamkan di dekat kota London, Inggris.
Sumber: pandri-16.blogspot.com
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