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  Arif 04:55:12 pm on January 6, 2010 | 0 | # |
  Tags: basic, spectrophotometry, wikipedia

  

  how spectrophotometer works

  There are two major classes of devices: (1) single beam and (2) double beam. A double beam spectrophotometer compares the light intensity between two light paths, one path containing a reference sample and the other the test sample.

  Wikipedia File:Spetrophotometer-en.svg

  In short, the sequence of events in a spectrophotometer is as follows:

  1. The light source shines into a monochromator.
  2. A particular output wavelength is selected and beamed at the sample.
  3. The sample absorbs light.

  intensity of that particular wavelength (I vs nm) is recorded.

   

• Arif 04:50:35 pm on January 6, 2010 | 0 | # |
  Tags: basic, spectrophotometry, wikipedia

  A spectrophotometer is a photometer (a device for measuring light intensity) that can measure intensity as a function of the color (or more specifically the wavelength) of light.

   

• Arif 04:57:56 pm on January 1, 2010 | 0 | # |
  Tags: basic, equation, interfacial tension, Myers 2006, Pashley 2004

  Young Laplace equation:

  

  other uses γ instead of σ for surface/interfacial tension (i.e. Pashley 2004). Common unit is dyne/cm (1 dyne = 1 micro Newton (μN) ).

   

• Arif 03:37:51 pm on January 1, 2010 | 0 | # |
  Tags: basic, chemistry, data source, MES

  organic chemistry of methyl ester sulfonate (MES) surfactant:

  RCH(CO₂Me)SO₃Na
  "tail" "head"
  hydrophobic hydrophilic

  Anionic: the hydrophile is a negatively charged group i.e. sulfonate RSO₃^- M⁺

   

• Arif 03:19:15 pm on January 1, 2010 | 0 | # |
  Tags: basic, chemistry, Myers 2006, surfactant

  organic chemistry of surfactant:

  CH₃(CH₂)_nCH₂S
  "tail" "head"
  hydrophobic hydrophilic

   

• Arif 12:43:53 pm on December 31, 2009 | 0 | # |
  Tags: basic, interfacial tension, Pashley 2004

  Surface energy of a liquid actually gives rise to a ‘surface tension’ or force acting to oppose any increase in surface area.

  Thus, we have to ‘blow’ to create a soap bubble by stretching a soap film. A spherical soap bubble is formed in response to the tension in the bubble surface.

   

• Arif 08:32:05 am on December 31, 2009 | 0 | # |
  Tags: basic, interfacial tension, wikipedia

  Surface tension is a property of the surface of a liquid. It is what causes the surface portion of liquid to be attracted to another surface, such as that of another portion of liquid (as in connecting bits of water or as in a drop of mercury that forms a cohesive ball).

  Separation of oil and water is caused by a tension in the surface between dissimilar liquids. This type of surface tension is called “interface tension“, but its physics are the same.

   

• Arif 01:35:05 pm on December 25, 2009 | 0 | # |
  Tags: basic, Myers 2006, oil recovery, quality metric, surfactant

  (1) Proper wetting of oil-bearing formations, (2) microemulsion formation and solubilization properties, (3) ease of emulsion breaking after oil recovery.

   

• Arif 01:27:43 pm on December 25, 2009 | 0 | # |
  Tags: basic, Myers 2006, properties, surfactant

  The properties and applications of surfactants are determined by the balance between the lyophilic (‘‘solvent-loving’’  and lyophobic (‘‘solvent-hating’’) portions of the molecules. (There are also water-loving hydrophilic, water-hating hydrophobic, fat-loving lipophilic, and fat-hating lipophobic).

  For that reason, such characteristics as solubility, surface tension reducing capability, critical micelle concentration (cmc), detergency power, wetting control, and foaming capacity may make a given surfactant perform well in some applications and less well in others. The ‘‘univer-
  sal’’ surfactant that meets all the varied needs of surfactant applications has yet to emerge from the industrial or academic laboratory.

   

• Arif 08:06:19 am on December 20, 2009 | 0 | # |
  Tags: basic, spectrophotometry, wikipedia

  spectrophotometry is the quantifiable study of electromagnetic spectra. More specific than the general term electromagnetic spectroscopy in that spectrophotometry deals with visible light, near-ultraviolet, and near-infrared.

   
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  abstract back-propagation basic book capillary force chemistry cons cross-validation data source density determination Drelich 2002 equation error Escobedo 1996 Escobedo 1998 huff and puff interfacial tension Isha 2006 Kumar 2005 Mansoori 1990 MES method mixture Myers 2006 neural network oil recovery Pashley 2004 pH prediction pure compound quality metric Queimada 2004 reference Silvert 1998 softcomputing spectrophotometry standard citation surfactant Touhami 1998 viscosity wavelength why? wikipedia Yan 2002

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