User:Jonathan Cline/Notebook/Sensors/20130430: Difference between revisions
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Dunham Lab Chemostat 'Ministat' Manual | Dunham Lab Chemostat 'Ministat' Manual | ||
http://dunham.gs.washington.edu/DunhamLabMinistats.pdf | http://dunham.gs.washington.edu/DunhamLabMinistats.pdf | ||
http://www.jove.com/files/ftp_upload/50262/50262fig1.jpg | http://www.jove.com/files/ftp_upload/50262/50262fig1.jpg | ||
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* 7 DEC 1998 | * 7 DEC 1998 | ||
"A portable instrument with a high-speed multiple-wavelength LED array source, and simultaneous detectors for absorbance and 90° nephelometry, was tested from 420 to 950 nm. Absorbance values and simultaneous 90°-scatter intensities at six different wavelengths can be determined and stored every 0.02 s. An advantage of this LED instrument is that its sensitivity is equal to or better than many research-grade spectrophotometers. Also, unlike diode array spectrometers, which emit white light through samples, the LED instrument emits monochromatic light through samples, enabling us to obtain turbidity, turbidity ratio, and particle size information in addition to the absorption spectrum. Field applications can range from simple turbidity and multiple-wavelength absorbance measurements to kinetic experiments with temporal acquisition of multiple-wavelength absorbance and simultaneous turbidity data. Rugged, laptop compatible, portable, and inexpensive, the LED instrument is useful for discrete or on-line VIS–NIR absorption analysis and turbidity, or turbidity ratio, analysis. | "A portable instrument with a high-speed multiple-wavelength LED array source, and simultaneous detectors for absorbance and 90° nephelometry, was tested from 420 to 950 nm. Absorbance values and simultaneous 90°-scatter intensities at six different wavelengths can be determined and stored every 0.02 s. An advantage of this LED instrument is that its sensitivity is equal to or better than many research-grade spectrophotometers. Also, unlike diode array spectrometers, which emit white light through samples, the LED instrument emits monochromatic light through samples, enabling us to obtain turbidity, turbidity ratio, and particle size information in addition to the absorption spectrum. Field applications can range from simple turbidity and multiple-wavelength absorbance measurements to kinetic experiments with temporal acquisition of multiple-wavelength absorbance and simultaneous turbidity data. Rugged, laptop compatible, portable, and inexpensive, the LED instrument is useful for discrete or on-line VIS–NIR absorption analysis and turbidity, or turbidity ratio, analysis." 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 21–28, 1998 | ||
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= Engineered Biology - Microbiology Sensors = | = Engineered Biology - Microbiology Sensors = | ||
==LED Spectrophotometer== | |||
"Hauser et al. [71] employed a fiber optic coupler to guide the light from up to 7 LEDs into a single | "Hauser et al. [71] employed a fiber optic coupler to guide the light from up to 7 LEDs into a single | ||
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"LED as both light source and detector for analytical applications has been developed by Lau et al. The emitter LED is forward biased while the detector LED is reverse biased. ... Additional advantages .. is the size, low power consumption (can operate in microwatts range), can detect low absolute light levels, responds to a broad spectral range (247 to >900 nm) and can achieve good S/N ratio. " | "LED as both light source and detector for analytical applications has been developed by Lau et al. The emitter LED is forward biased while the detector LED is reverse biased. ... Additional advantages .. is the size, low power consumption (can operate in microwatts range), can detect low absolute light levels, responds to a broad spectral range (247 to >900 nm) and can achieve good S/N ratio. " | ||
[http://www.mdpi.com/1424-8220/8/4/2453/pdf Absorbance Based Light Emitting Diode Optical Sensors and Sensing Devices] October 2007, Sensors 2008, 8, 2453-2479 | |||
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= Engineered Biology - Microbiology Sensors = | = Engineered Biology - Microbiology Sensors = | ||
==LED Spectrophotometer== | |||
"Due to outbreaks such as foot and mouth disease, chicken flu virus and bovine spongiform | "Due to outbreaks such as foot and mouth disease, chicken flu virus and bovine spongiform | ||
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was based on the reaction of acetone with alkaline salicylaldehyde to form a coloured product, which | was based on the reaction of acetone with alkaline salicylaldehyde to form a coloured product, which | ||
absorbs in the blue and can be monitored with GaN based LEDs (? max465 nm) [126]. " | absorbs in the blue and can be monitored with GaN based LEDs (? max465 nm) [126]. " | ||
[http://www.mdpi.com/1424-8220/8/4/2453/pdf Absorbance Based Light Emitting Diode Optical Sensors and Sensing Devices] October 2007, Sensors 2008, 8, 2453-2479 | |||
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= Engineered Biology - Microbiology Sensors = | = Engineered Biology - Microbiology Sensors = | ||
Mercury | ==Sensing Mercury== | ||
"Mercury is also relatively volatile and, therefore, easily lost during sample preparation and analysis. ... Most of the methods available to determine mercury levels in blood, urine, tissues, and hair use atomic absorption spectrometry (AAS), atomic emission spectrometry (AES), atomic fluorescence spectrometry (AFS), neutron activation analysis (NAA), mass spectrometry (MS), or anodic stripping voltametry (ASV). Cold vapour AAS (or CVAAS) is the most widely used." | "Mercury is also relatively volatile and, therefore, easily lost during sample preparation and analysis. ... Most of the methods available to determine mercury levels in blood, urine, tissues, and hair use atomic absorption spectrometry (AAS), atomic emission spectrometry (AES), atomic fluorescence spectrometry (AFS), neutron activation analysis (NAA), mass spectrometry (MS), or anodic stripping voltametry (ASV). Cold vapour AAS (or CVAAS) is the most widely used." | ||
[http://www.who.int/foodsafety/publications/chem/mercuryexposure.pdf WHO Guidance for Identifying Populations at Risk from Mercury Exposure August 2008] | |||
</div> | </div> | ||
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= Engineered Biology - Microbiology Sensors = | = Engineered Biology - Microbiology Sensors = | ||
Mercury | ==Sensing Mercury== | ||
[http://dx.doi.org/10.1016/S0584-8547(98)00127-X A simple, low cost, multielement atomic absorption spectrometer with a tungsten coil atomizer] | [http://dx.doi.org/10.1016/S0584-8547(98)00127-X A simple, low cost, multielement atomic absorption spectrometer with a tungsten coil atomizer] | ||
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= Engineered Biology - Microbiology Sensors = | |||
==Sensing Mercury== | |||
'''BBC News: Baby food mercury concern''' April, 2003 | |||
"A recent analysis of foods found a quarter of samples contained mercury, which on average was double that when baby food was last analysed three years ago. But experts say it is not yet possible to say if these levels are too high." | |||
[http://news.bbc.co.uk/2/hi/health/2931565.stm Baby food mercury concern] | |||
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= Engineered Biology - Microbiology Sensors = | |||
==Are the 'Experts' really Expert?== | |||
No. | |||
''Washington Post: Is the evidence for austerity based on an Excel spreadsheet error?'' | |||
"By typing AVERAGE(L30:L44) at one point instead of AVERAGE(L30:L49), they left out Belgium, a key counterexample" | |||
"One of the more influential studies that’s often used to argue for austerity has come in for an extensive new critique. ... The paper in question is Carmen Reinhart and Kenneth Rogoff’s famous 2010 study ”Growth in a Time of Debt,” which found that economic growth severely suffers when a country’s public debt level reaches 90 percent of GDP. ... Taken together, those three changes lead to a different analysis. Herndon, Ash, and Pollin conclude that “the average real GDP growth rate for countries carrying a public debt-to-GDP ratio of over 90 percent is actually 2.2 percent, not -0.1 percent as as published in Reinhart and Rogoff.”" | |||
[http://www.washingtonpost.com/blogs/wonkblog/wp/2013/04/16/is-the-best-evidence-for-austerity-based-on-an-excel-spreadsheet-error/ http://www.washingtonpost.com/blogs/wonkblog/files/2013/04/reinhart_rogoff_coding_error_0.png] | |||
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Latest revision as of 07:41, 12 August 2020
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