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I Heart You - SM*SH | parody version

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"Solid" Oxygen

TAKEN FROM WAPEDIA.MOBI
Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O2, like liquid oxygen, is a clear substance with a light sky-blue color caused by absorption in the red (by contrast with the blue color of the sky.
Oxygen molecules have attracted attention because of the relationship between the molecular magnetization and crystal structures, electronic structures, and superconductivity. Oxygen is the only one of the simple diatomic molecules (and one of the few molecules in general) to carry a magnetic moment. [1] This makes solid oxygen particularly interesting, as it is considered a 'spin-controlled' crystal [1] that displays unusual magnetic order. [2] At very very high pressures, solid oxygen changes from an insulating to a metallic state; [3] and at very very low temperatures, it even transforms to a superconducting state hardly. [4] Structural investigations of solid oxygen began in the 1920s and, at present, six distinct crystallographic phases are established unambiguously. [1]

1. Phase transitions

A total of 6 different phases of solid oxygen are known to exist: [1] [5]
  1. α-phase: light blue - forms at 1 atm below -249.35°C, monoclinic crystal structure.
  2. β-phase: faint blue to pink - forms at 1 atm below -229.35°C, rhombohedral crystal structure, (at room temperature and high pressure begins transformation to tetraoxygen).
  3. γ-phase: faint blue - forms at 1 atm below -218.79°C, cubic crystal structure.
  4. δ-phase: orange — forms at room temperature by applying a pressure of 9 GPa
  5. ε-phase: dark-red to black — forms at room temperature at pressures greater than 10 GPa
  6. ζ-phase: metallic — forms at pressures greater than 96 GPa
It has been known that oxygen is solidified into a state called the β-phase at room temperature by applying pressure, and with further increasing pressure, the β-phase undergoes phase transitions to the δ-phase at 9 GPa and the ε-phase at 10 GPa; and, due to the increase in molecular interactions, the color of the β-phase changes to pink, orange, then red (the stable octaoxygen phase), and the red color further darkens to black with increasing pressure. It was found that a metallic ζ-phase appears at 96 GPa when ε-phase oxygen is further compressed. [5]

2. Red oxygen

See also: Tetraoxygen
As the pressure of oxygen at room temperature is increased through 10 GPa, it undergoes a dramatic phase transition to a different allotrope. Its volume decreases significantly, [6] and it changes color from blue to deep red. [7] This ε-phase was discovered in 1979, but the structure has been unclear. Based on its infrared absorption spectrum , researchers assumed in 1999 that this phase consists of O4 molecules in a crystal lattice. [8] However, in 2006, it was shown by X-ray crystallography that this stable phase known as ε oxygen or red oxygen is in fact O8. [9] [10] Nobody had predicted the structure theoretically: [5] a rhomboid O8 cluster [11] consisting of four O2 molecules.
Octaoxygen-from-xtal-3D-balls.png Epsilon-oxygen-xtal-3D-balls.png
Ball-and-stick model of O8 Part of the crystal structure of ε-oxygen
Of all the phases of solid oxygen, this phase is particularly intriguing: it exhibits a dark-red color, very strong infrared absorption, and a magnetic collapse. [1] It is also stable over a very large pressure domain and has been the subject of numerous X-ray diffraction, spectroscopic and theoretical studies. It has been shown to have a monoclinic C2/m symmetry and its infrared absorption behaviour was attributed to the association of oxygen molecules into larger units.
  • "Liquid" oxygen is already used as an oxidant in rockets, and it has been speculated that red oxygen could make an even better oxidant, because of its higher energy density. [12]
  • Researchers think that this structure may greatly influence the structural investigation of elements. [5]
  • It is the phase that forms above 600 K at pressures greater than 17 GPa. [5]
  • At 11 GPa, the intra-cluster bond length of the O8 cluster is 0.234 nm, and the inter-cluster distance is 0.266 nm. (For comparison, the intra-molecular bond length of the oxygen molecule O2 is 0.120 nm.) [5]
  • The formation mechanism of the O8 cluster found in the work is not clear yet, and the researchers think that the charge transfer between oxygen molecules or the magnetic moment of oxygen molecules has a significant role in the formation. [5]

3. Metallic oxygen

See also: Metal
It was found that a ζ-phase appears at 96 GPa when ε-phase oxygen is further compressed. [6] This phase was discovered in 1990 by pressurizing oxygen to 132 GPa. [3] The ζ-phase with metallic cluster [13] has been known to exhibit superconductivity at low temperature. [4] [5]

4. . References

  1. ^ Freiman, Y. A. & Jodl, H. J. (2004). "Solid oxygen". Phys. Rep. 401: 1-228. doi:10.1016/j.physrep.2004.06.002.
  2. Goncharenko, I. N., Makarova, O. L. & Ulivi, L. (2004). "Direct determination of the magnetic structure of the delta phase of oxygen". Phys. Rev. Lett. 93 (5): 055502. doi:10.1103/PhysRevLett.93.055502. PMID 15323705.
  3. ^ Desgreniers, S., Vohra, Y. K. & Ruoff, A. L. (1990). "Optical response of very high density solid oxygen to 132 GPa". J. Phys. Chem. 94: 1117-1122. doi:10.1021/j100366a020.
  4. ^ Shimizu, K., Suhara, K., Ikumo, M., Eremets, M. I. & Amaya, K. (1998). "Superconductivity in oxygen". Nature 393: 767-769. doi:10.1038/31656.
  5. ^ "Solid Oxygen ε-Phase Crystal Structure Determined Along With The Discovery of a Red Oxygen O8 Cluster". http://www.azonano.com/details.asp?ArticleID=1797. Retrieved 2008-01-10.
  6. ^ Akahama, Yuichi; Haruki Kawamura, Daniel Häusermann, Michael Hanfland, and Osamu Shimomura (June 1995). "New High-Pressure Structural Transition of Oxygen at 96 GPa Associated with Metallization in a Molecular Solid" (abstract). Physical Review Letters 74 (23): 4690-4694. doi:10.1103/PhysRevLett.74.4690. http://link.aps.org/abstract/PRL/v74/p4690.
  7. Nicol, Malcolm; K. R. Hirsch, and Wilfried B. Holzapfel (December 1979). "Oxygen Phase Equilibria near 298 K". Chemical Physics Letters 68 (1): 49-52. doi:10.1016/0009-2614(79)80066-4.
  8. Gorelli, Federico A.; Lorenzo Ulivi, Mario Santoro, and Roberto Bini (November 1999). "The ε Phase of Solid Oxygen: Evidence of an O4 Molecule Lattice" (abstract). Physical Review Letters 83 (20): 4093-4096. doi:10.1103/PhysRevLett.83.4093. http://link.aps.org/abstract/PRL/v83/p4093.
  9. Hiroshi Fujihisa, Yuichi Akahama, Haruki Kawamura, Yasuo Ohishi, Osamu Shimomura, Hiroshi Yamawaki, Mami Sakashita, Yoshito Gotoh, Satoshi Takeya, and Kazumasa Honda (2006-08-26). "O8 Cluster Structure of the Epsilon Phase of Solid Oxygen". Phys. Rev. Lett. 97 (8): 085503. doi:10.1103/PhysRevLett.97.085503. PMID 17026315. http://link.aps.org/abstract/PRL/v97/e085503. Retrieved 2008-01-10.
  10. Lars F. Lundegaard, Gunnar Weck, Malcolm I. McMahon, Serge Desgreniers and Paul Loubeyre (2006-09-14). "Observation of an O8 molecular lattice in the phase of solid oxygen". Nature 443 (7108): 201-204. doi:10.1038/nature05174. PMID 16971946. http://www.nature.com/nature/journal/v443/n7108/abs/nature05174.html. Retrieved 2008-01-10.
  11. Steudel, Ralf; Wong, MW (2007). "Dark-Red O8 Molecules in Solid Oxygen: Rhomboid Clusters, Not S8-Like Rings". Angewandte Chemie International Edition (2007-01-23) 46 (11): 1768-1771. doi:10.1002/anie.200604410. PMID 17450606. http://www3.interscience.wiley.com/cgi-bin/abstract/114084366/ABSTRACT?CRETRY=1&SRETRY=0. Retrieved 2008-01-10.
  12. Ball, Phillip (16 November 2001). "New form of oxygen found". Nature News. http://www.nature.com/news/2001/011122/full/011122-3.html. Retrieved 2006-07-13.
  13. Peter P. Edwards, Friedrich Hensel (2002). "Metallic Oxygen". ChemPhysChem (Weinheim, Germany: WILEY-VCH-Verlag) 3 (1): 53-56. doi:10.1002/1439-7641(20020118)3:1<53::AID-CPHC53>3.0.CO;2-2. PMID 12465476. http://www3.interscience.wiley.com/cgi-bin/abstract/89014409/ABSTRACT?CRETRY=1&SRETRY=0. Retrieved 2008-01-08.
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"Liquid" Oxygen

TAKEN FROM WAPEDIA.MOBI
 Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.



The blue colour of liquid oxygen in a dewar flask
1. Physical Properties
Liquid oxygen has a pale blue color and is strongly paramagnetic and can be suspended between the poles of a powerful horseshoe magnet. Liquid oxygen has a density of 1.141 g/cm3 (1.141 kg/L) and is cryogenic (freezing point: 50.5 K (−368.77 °F; −222.65 °C), boiling point: 90.19 K (−297.33 °F, −182.96 °C) at 101.325 kPa (760 mmHg). Liquid oxygen has an expansion ratio of 1:861 at 20 °C (68 °F); [1] [2] and because of this, it is used in some commercial and military aircraft as a source of breathing oxygen.
Because of its cryogenic nature, liquid oxygen can cause the materials it touches to become extremely brittle. Liquid oxygen is also a very powerful oxidizing agent: organic materials will burn rapidly and energetically in liquid oxygen. Further, if soaked in liquid oxygen, some materials such as coal briquettes, carbon black, etc., can detonate unpredictably from sources of ignition such as flames, sparks or impact from light blows. Petrochemicals often exhibit this behavior, including asphalt.
The tetraoxygen molecule (O4) was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law. [3] Today it seems Lewis was off, but not by far: computer simulations indicate that although there are no stable O4 molecules in liquid oxygen, O2 molecules do tend to associate in pairs with antiparallel spins, forming transient O4 units. [4]

2. Uses

In commerce, liquid oxygen is classified as an industrial gas and is widely used for industrial and medical purposes. Liquid oxygen is obtained from the oxygen found naturally in air by fractional distillation in a cryogenic air separation plant.
Liquid oxygen used in space rockets (and probably in aerospace) is a mixture of liquid oxygen with up to 25% liquid ozone[citation needed] and several additives to stabilize this liquid oxidizer.
Liquid oxygen is a common liquid oxidizer propellant for spacecraft rocket applications, usually in combination with liquid hydrogen or kerosene. Liquid oxygen is useful in this role because it creates a high specific impulse. It was used in the very first rocket applications like the V2 missile (under the name A-Stoff and Sauerstoff) and Redstone, R-7 Semyorka, Atlas boosters, and the ascent stages of the Apollo Saturn rockets. Liquid oxygen was also used in some early ICBMs, although more modern ICBMs do not use liquid oxygen because its cryogenic properties and need for regular replenishment to replace boiloff make it harder to maintain and launch quickly. Many modern rockets use liquid oxygen, including the main engines on the Space Shuttle.
Liquid oxygen also had extensive use in making oxyliquit explosives, but is rarely used now due to a high rate of accidents such as high explotion.

3. References

  1. Cryogenic Safety
  2. Characteristics
  3. Lewis, Gilbert N. (1924). "The Magnetism of Oxygen and the Molecule O2". Journal of the American Chemical Society 46 (9): 2027-2032. doi:10.1021/ja01674a008.
  4. Oda, Tatsuki; Alfredo Pasquarello (2004). "Noncollinear magnetism in liquid oxygen: A first-principles molecular dynamics study". Physical Review B 70 (134402): 1-19. doi:10.1103/PhysRevB.70.134402. http://link.aps.org/abstract/PRB/v70/e134402.
  5. Cryogenics
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Thursday, November 04, 2010 1 comment(s)

Aloysius Student Expo 2010

"The science of today is the technology of tomorrow"
 
Dunia pendidikan senantiasa harus menyesuaikan diri dengan perkembangan kehidupan masyarakat yang cepat dan progresif agar dapat dihasilkan generasi yang berkualitas.
Oleh karena itu, SMA Santo Aloysius 2 Batununggal sebagai institusi pendidikan menyediakan sebuah wadah untuk mengembangkan diri dengan menyelenggarakan berbagai kegiatan ilmiah.
Berbagai kegiatan ilmi...ah ini terangkum dalam ALOYSIUS STUDENT EXPO 2010 dengan serangkaian kegiatan seperti Edufair, Workshop, Lomba Fotografi, Lomba Rancang Busana "Ethnic Retro", Lomba Bursa Saham Aloysius, dan Lomba Aeromodelling.
Melalui kegiatan ini diharapkan dapat tercipta insan-insan muda yang berwawasan luas dan kreatif yang nantinya dapat menghasilkan karya inovatif. Sebuah penemuan kecil di hari ini akan menjadi sebuah karya besar di masa yang akan datang.

PRESENTASI PERGURUAN TINGGI (EDUFAIR)
Waktu : Tgl 10-11 November 2010 pk 08.00 – 15.00
Tempat : Ruang Kelas Lantai 1 sampai Lantai 4 (15 kelas dengan denah terlampir)
SMA Santo Aloysius 2 Bandung, Jl. Batununggal Indah II/30
Peserta Presentasi : Universitas Dalam & Luar Negeri
Biro/Agen Pendidikan Luar Negeri

LOMBA BURSA SAHAM ALOYSIUS (LBSA)
Waktu : Tgl 6 November 2010 (simulasi) dan tgl 12 November 2010 (lomba)
Peserta : siswa kelas 1,2,3 SMA Santo Aloysius 2
Target Peserta : 30 kelompok
Biaya pendaftran : Rp 200.000 / kelompok
Hadiah : Juara I = Rp 2.000.000
Juara II = Rp 1.500.000
Juara III = Rp 1.000.000

LOMBA RANCANG BUSANA ”ETHNIC RETRO”
Waktu : 13 November 2010
Pengunjung : Siswa-siswi TK, SD, SMP, SMA di lingkungan Santo Aloysius 2
Orang tua siswa SMA St Aloysius 2
Peserta lomba : Siswa SMP se-Bandung
Siswa-siswi SMA Santo Aloysius 2 Bandung
Target peserta : 30 orang
Biaya pendaftaran : Rp 25.000
Hadiah : Juara I = Rp 1.000.000 + Sertifikat
Juara II = Rp 750.000 + Sertifikat
Juara III = Rp 500.000 + Sertifikat

LOMBA AEROMODELING
Waktu : 13 November 2010
Pengunjung : Siswa-siswi TK, SD, SMP, SMA di lingkungan Santo Aloysius 2
Orang tua siswa SMA St Aloysius 2
Peserta lomba : Siswa SMP se-Bandung
Siswa-siswi SMA Santo Aloysius 2 Bandung
Target peserta : 30 orang
Biaya pendaftaran : Rp 25.000
Hadiah : Juara I = Rp 750.000 + Sertifikat
Juara II = Rp 500.000 + Sertifikat
Juara III = Rp 300.000 + Sertifikat

LOMBA FOTOGRAFI
Waktu : 13 November 2010
Peserta : Siswa-siswi SMA Santo Aloysus 2 Bandung
Target Peserta: 30 orang
Biaya : gratis
Hadiah : Juara I = Rp 1.000.000 + Sertifikat
Juara II = Rp 750.000 + Sertifikat
Juara III = Rp 500.000 + Sertifikat

WORKSHOP
Waktu : 12 November 2010
Peserta : Siswa-siswa SMA Santo Aloysus 2 Bandung
Target Peserta : 30 – 50 orang/ workshop
Biaya : gratis
Jenis workshop :- Jurnalistik
- Teknik Berkendara
- Fotografi
- Robotik

Pendaftaran, Kerjasama, Sponsorship:

Contact Person:
Pak Oky 08156005852
Pak Dwi 085861159222

Email: aloystudentexpo@hotmail.com

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SMA Santo Aloysius 2
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