Perchlorate, a main component in making explosives, fireworks, air bags and rocket fuel, is contaminating our water and food supply due to improper disposal at rocket-testing sites, military bases and chemical plants. Known to cause development delays and low IQ levels when exposed to young children, the U.S. Environmental Protection Agency (EPA) found “unsafe levels” to be in the drinking water of 17 million people. Independent researchers estimate the number to be closer to the 20-40 million range. In a 2006 study, the FDA found the toxin hiding in over half of the food samples they analyzed, including fruits, vegetables and infant formulas.
This month, the EPA announced its plan to begin immediately forming regulation standards for the chemical over the next two years. This comes after many years of heavy opposition to regulation from the Pentagon and Defense Department, whose military bases and rocket test sites are the causes of the contamination. Cleanup of such sites would cost them millions of dollars. The Perchlorate Information Bureau, an industry-supported group, has argued that there is “no research” to support health claims regarding perchlorate.
These groups “have distorted the science to such an extent that they can justify not regulating [the chemical]. Infants and children will continue to be damaged, and that damage is significant,” said Robert Zoeller, a professor at the University of Massachusetts who specializes in thyroid hormone and brain development.
The EPA’s regulation will implement new clean-water technologies to treat perchlorate-contaminated groundwater, pioneered by the award-winning engineering firm Solutions-IES.
“(C)lean and safe water is not a luxury or a privilege, it is a right of all Americans,” said EPA Administrator Lisa Jackson in statements to U.S. lawmakers. California legislators, the state with the most affected water supplies, celebrated the victory. “I will do everything I can to make sure this new protection moves forward,” said Senator Barbara Boxer.
Sources: EPA; Natural Resources Defense Council on www.emagazine.com/daily-news
Rabu, 16 Februari 2011
Senin, 14 Februari 2011
Carbon Nanotube-Based Integrated Circuits Manufactured on Plastic Substrates
Successful Operation of Carbon Nanotube-Based Integrated Circuits Manufactured on Plastic Substrates
ScienceDaily (Feb. 9, 2011) — As part of NEDO's Industrial Technology Research Grant Japan-Finland collaborative project, Professors Yutaka Ohno from Nagoya University in Japan and Esko I. Kauppinen from Aalto University in Finland along with their colleagues have developed a simple and fast process to manufacture high-quality carbon nanotube-based thin film transistors (TFT) on a plastic substrate.
They used this technology to manufacture the world's first sequential logic circuits using carbon nanotubes. The technology could lead to the development of high-speed, roll-to-roll manufacturing processes to manufacture low-cost flexible devices such as electronic paper in the future.
The results were published on Feb. 6, 2011 in the online edition of the journal Nature Nanotechnology.
Background
Lightweight and flexible devices such as mobile phones and electronic paper are gaining attention for their roles in achieving a smarter ubiquitous information society. For flexible electronics, as a substitute for conventional solid silicon substrates, there is a demand for integrated circuits to be manufactured on a plastic substrate with high speed and low cost .
Thus far, flexible thin-film transistors (TFT) have been produced using a variety of semiconductor materials such as silicon and zinc-oxide, which require vacuum deposition, high-temperature curing, and complex transfer processes. In recent years, organic semiconductors have been rapidly developing, however such semiconductors still have low-mobility and there are problems with their chemical stability. Recently, carbon nanotube thin films have been attracting attention due to their chemical stability and high-mobility. However, although simple solution processes have been developed to produce TFTs, such TFTs have not been yet fulfilled capability expectations thus far, due to the deterioration of the conduction properties of carbon nanotube thin films through the dispersion process in the solution.
Results
(1) Easy and fast thin film deposition: Gas phase filtration and transfer processes
In conventional solution processes, soot-like carbon nanotube material is first dispersed in liquid via sonication to purify the materials and to separate the tubes from each other. In such processes, it is difficult to form homogeneous carbon nanotube films. In addition, technology has not yet been developed to completely remove the dispersant. In contrast, using our innovative technology, we continuously grow nanotubes in an atmospheric pressure chemical-vapor deposition process. The nanotubes are then collected on the filter and subsequently transferred onto a polymer substrate using simple gas-phase filtration and transfer processes to achieve clean, uniform carbon nanotube films. It takes only a few seconds to deposit the carbon nanotubes. This process may be adaptable to high-speed roll-to-roll manufacturing systems in the near future.
(2) Carbon nanotube TFTs with high-mobility of 35 cm2/Vs and an on/off ratio of 6´106
In conventional solution-based carbon nanotube TFT manufacturing processes, nanotubes are dispersed using powerful ultrasound which cuts the nanotubes and reduces their length. Due to high contact resistance between these short nanotubes and the residual impurities caused by the dispersion process, the resulting TFT mobility was approximately 1 cm2/Vs. Due to the doping effect caused by residual impurities from the dispersion, the on/off ratio was only between about 104~105. When carbon nanotube thin films are manufactured using the above gas-phase filtration and transfer processes, the tubes in the film are as clean and long as those that are grown in the synthesis processes. Accordingly, TFTs with a high mobility of 35 cm2/Vs were achieved. In addition, due to precision control of the nanotube density, an on/off ratio of 6x106 was simultaneously achieved. The TFT performance we have achieved is significantly higher than the performance of organic semiconductor TFTs and carbon nanotube TFTs reported so far, and equal to the performance of low-temperature polycrystalline silicon as well as zinc oxide TFTs, which are manufactured using high-temperature processes and vacuum-based processes.
(3) Successful operation of integrated circuits on transparent and flexible plastic substrates
The gas-phase filtration and transfer processes can be applied to manufacture devices on any substrate material. This time, we integrated the high-performance carbon nanotube TFTs on plastic substrates, and achieved successful operations of ring oscillators and flip-flops. High-speed operations have been achieved with a delay time of 12 microseconds per logic gate. The flip-flops that have been manufactured through these processes are the world's first carbon nanotube-based synchronous sequential logic circuits.
Taken from: http://www.sciencedaily.com/releases/2011/02/110208091557.htm
ScienceDaily (Feb. 9, 2011) — As part of NEDO's Industrial Technology Research Grant Japan-Finland collaborative project, Professors Yutaka Ohno from Nagoya University in Japan and Esko I. Kauppinen from Aalto University in Finland along with their colleagues have developed a simple and fast process to manufacture high-quality carbon nanotube-based thin film transistors (TFT) on a plastic substrate.
They used this technology to manufacture the world's first sequential logic circuits using carbon nanotubes. The technology could lead to the development of high-speed, roll-to-roll manufacturing processes to manufacture low-cost flexible devices such as electronic paper in the future.
The results were published on Feb. 6, 2011 in the online edition of the journal Nature Nanotechnology.
Background
Lightweight and flexible devices such as mobile phones and electronic paper are gaining attention for their roles in achieving a smarter ubiquitous information society. For flexible electronics, as a substitute for conventional solid silicon substrates, there is a demand for integrated circuits to be manufactured on a plastic substrate with high speed and low cost .
Thus far, flexible thin-film transistors (TFT) have been produced using a variety of semiconductor materials such as silicon and zinc-oxide, which require vacuum deposition, high-temperature curing, and complex transfer processes. In recent years, organic semiconductors have been rapidly developing, however such semiconductors still have low-mobility and there are problems with their chemical stability. Recently, carbon nanotube thin films have been attracting attention due to their chemical stability and high-mobility. However, although simple solution processes have been developed to produce TFTs, such TFTs have not been yet fulfilled capability expectations thus far, due to the deterioration of the conduction properties of carbon nanotube thin films through the dispersion process in the solution.
Results
(1) Easy and fast thin film deposition: Gas phase filtration and transfer processes
In conventional solution processes, soot-like carbon nanotube material is first dispersed in liquid via sonication to purify the materials and to separate the tubes from each other. In such processes, it is difficult to form homogeneous carbon nanotube films. In addition, technology has not yet been developed to completely remove the dispersant. In contrast, using our innovative technology, we continuously grow nanotubes in an atmospheric pressure chemical-vapor deposition process. The nanotubes are then collected on the filter and subsequently transferred onto a polymer substrate using simple gas-phase filtration and transfer processes to achieve clean, uniform carbon nanotube films. It takes only a few seconds to deposit the carbon nanotubes. This process may be adaptable to high-speed roll-to-roll manufacturing systems in the near future.
(2) Carbon nanotube TFTs with high-mobility of 35 cm2/Vs and an on/off ratio of 6´106
In conventional solution-based carbon nanotube TFT manufacturing processes, nanotubes are dispersed using powerful ultrasound which cuts the nanotubes and reduces their length. Due to high contact resistance between these short nanotubes and the residual impurities caused by the dispersion process, the resulting TFT mobility was approximately 1 cm2/Vs. Due to the doping effect caused by residual impurities from the dispersion, the on/off ratio was only between about 104~105. When carbon nanotube thin films are manufactured using the above gas-phase filtration and transfer processes, the tubes in the film are as clean and long as those that are grown in the synthesis processes. Accordingly, TFTs with a high mobility of 35 cm2/Vs were achieved. In addition, due to precision control of the nanotube density, an on/off ratio of 6x106 was simultaneously achieved. The TFT performance we have achieved is significantly higher than the performance of organic semiconductor TFTs and carbon nanotube TFTs reported so far, and equal to the performance of low-temperature polycrystalline silicon as well as zinc oxide TFTs, which are manufactured using high-temperature processes and vacuum-based processes.
(3) Successful operation of integrated circuits on transparent and flexible plastic substrates
The gas-phase filtration and transfer processes can be applied to manufacture devices on any substrate material. This time, we integrated the high-performance carbon nanotube TFTs on plastic substrates, and achieved successful operations of ring oscillators and flip-flops. High-speed operations have been achieved with a delay time of 12 microseconds per logic gate. The flip-flops that have been manufactured through these processes are the world's first carbon nanotube-based synchronous sequential logic circuits.
Taken from: http://www.sciencedaily.com/releases/2011/02/110208091557.htm
Pembuatan Gas Hidrogen
Cara Industri
Elektrolisis air yang sedikit diasamkan
2H2O (l) → 2H2 (g) + O2 (g)
Cara Laboratorium
Logam (golongan IA/IIA) + air
Contoh:
2K(s) + 2H2O(l) → 2KOH (aq) + H2 (g)
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
Cara Industri
3Fe(pijar) + 4H2O → Fe3O42(g) (s) + 4H
Cara Laboratorium
Contoh:
Logam dengan Eok o > O + asam kuat encer
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2(g)
Cara Industri
2C(pijar) + 2H2O (g) → 2H2 (g) + 2CO (g)
Cara Laboratorium
Logam amfoter + basa kuat
Contoh:
Zn (s) + NaOH(aq) → Na2ZnO2 (aq) + H2(g)
2Al (s) + 6NaOH (aq) → 2Na3AlO3 (aq) + 3H2(g)
Dipetik dari : www.chem-is-try.org/materi_kimia/kimia_sma1/kelas-3/pembuatan-gas-hidrogen/
Elektrolisis air yang sedikit diasamkan
2H2O (l) → 2H2 (g) + O2 (g)
Cara Laboratorium
Logam (golongan IA/IIA) + air
Contoh:
2K(s) + 2H2O(l) → 2KOH (aq) + H2 (g)
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
Cara Industri
3Fe(pijar) + 4H2O → Fe3O42(g) (s) + 4H
Cara Laboratorium
Contoh:
Logam dengan Eok o > O + asam kuat encer
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2(g)
Cara Industri
2C(pijar) + 2H2O (g) → 2H2 (g) + 2CO (g)
Cara Laboratorium
Logam amfoter + basa kuat
Contoh:
Zn (s) + NaOH(aq) → Na2ZnO2 (aq) + H2(g)
2Al (s) + 6NaOH (aq) → 2Na3AlO3 (aq) + 3H2(g)
Dipetik dari : www.chem-is-try.org/materi_kimia/kimia_sma1/kelas-3/pembuatan-gas-hidrogen/
Asal Kata Kimia atau Chemistry
Satu Hasil penelusuran Google:
Kimia (dari bahasa Arab كيمياء "seni transformasi" dan bahasa Yunani χημεία khemeia "alkimia") adalah ilmu yang mempelajari mengenai komposisi dan sifat zat ...
Pengantar - Sejarah - Cabang ilmu kimia - Konsep dasar
id.wikipedia.org/wiki/Kimia
Kimia (dari bahasa Arab كيمياء "seni transformasi" dan bahasa Yunani χημεία khemeia "alkimia") adalah ilmu yang mempelajari mengenai komposisi dan sifat zat ...
Pengantar - Sejarah - Cabang ilmu kimia - Konsep dasar
id.wikipedia.org/wiki/Kimia
Minggu, 13 Februari 2011
Juara Ujian secara Nasional
Juara kata ini berarti orang yang paling baik. Ujian berarti suatu proses untuk mendapatkan siapa yang menjadi juara. Juara Ujian berarti siapa yang menjadi paling baik kemampuan ilmu pengetahuannya pada suatu saat ada proses ujian.
Penentuan siapa sang juara prosesnya tidak sederhana. Ada berbagai pertimbangan dan kepentingan. Jalurnya bermacam-macam. Ada skor-skor yang ditentukan. Ada faktor-faktor yang dipertimbangkan. Ada tujuan-tujuan yang ingin dicapai.
Proses ujian pada pendidikan tidak hanya satu. Setidaknya dua jenis kejuaraan yang menonjol pertama yaitu kejuaran yang bertitel Ujian Nasional dan kedua yang bertitel Olimpiade Sain. Ujian Nasional media massa mengangkat tokohnya adalah Mendiknas, sedangkan olimpiade sebagian media massa mengangkat seorang tokoh juga.
Jika kita berpikir kejuaraan di pendidikan seperti kejuaraan tinju, maka untuk ujian berlaku ungkapan: juara ujian nasional, juara olimpiade, juara cerdas cermat, juara kuis, juara kelas, juara kabupaten lomba mata pelajaran. Ungkapan ini disandang bagi yang memenangkan kejuaraan.
Pemenang ujian nasional dan olimpiade di puji sekolah dan Dinas Pendidikan atau Departemen Pendidikan Nasional. Pemenang ujian semester pun demikian. Mendapat pujian dari Bapak atau Ibu Guru.
Mereka pemenang selain dipuji juga nanti dipakai oleh yang punya kepentingan. Baik kepentingan negatif maupun kepentingan positif.Nanti.
Salam.
Penentuan siapa sang juara prosesnya tidak sederhana. Ada berbagai pertimbangan dan kepentingan. Jalurnya bermacam-macam. Ada skor-skor yang ditentukan. Ada faktor-faktor yang dipertimbangkan. Ada tujuan-tujuan yang ingin dicapai.
Proses ujian pada pendidikan tidak hanya satu. Setidaknya dua jenis kejuaraan yang menonjol pertama yaitu kejuaran yang bertitel Ujian Nasional dan kedua yang bertitel Olimpiade Sain. Ujian Nasional media massa mengangkat tokohnya adalah Mendiknas, sedangkan olimpiade sebagian media massa mengangkat seorang tokoh juga.
Jika kita berpikir kejuaraan di pendidikan seperti kejuaraan tinju, maka untuk ujian berlaku ungkapan: juara ujian nasional, juara olimpiade, juara cerdas cermat, juara kuis, juara kelas, juara kabupaten lomba mata pelajaran. Ungkapan ini disandang bagi yang memenangkan kejuaraan.
Pemenang ujian nasional dan olimpiade di puji sekolah dan Dinas Pendidikan atau Departemen Pendidikan Nasional. Pemenang ujian semester pun demikian. Mendapat pujian dari Bapak atau Ibu Guru.
Mereka pemenang selain dipuji juga nanti dipakai oleh yang punya kepentingan. Baik kepentingan negatif maupun kepentingan positif.Nanti.
Salam.
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