Available Technology
Density determination of trace evidence via magnetic levitation
Technology:
Magnetic levitation
Markets Addressed
A low-cost device, making density determination of trace evidence easy, quick and affordable. The approach is nondestructive, verifiable and comparable. Results are quantitative and, thus enterable into and searchable against databases. Can be used to quickly and easily determine the density of trace items such as smokeless powders, fibers, rubber/plastic automotive trim fragments, glass fragments, paint chips, glitter, shimmer, bone fragments, ivory, wood fragments, dried tree sap and soil fractions.
Innovations and Advantages
Density is a universal property of matter and is one parameter that may be used to characterize a trace object. Although the formula for density (or specific gravity) is simply mass of the object divided by its volume, this is not easily obtained for tiny, irregularly-shaped objects. This method is based on magnetic levitation (MagLev): objects that are repelled from high magnetic fields (i.e., diamagnetic objects) are placed in a container filled with a solution that is attracted to high magnetic fields (i.e., a paramagnetic solution). When placed between two magnets, the diamagnetic objects are repelled from the magnets and ‘levitate’ within the paramagnetic solution. The levitation height of a diamagnetic object, within the magnetic field, is directly related to its density. The vertical position of the diamagnetic sample is independent of mass and/or volume, and thus eliminates the need for standardized sample sizes.
Key Advantages:
• Determination of density within minutes, without destroying the sample
• Can distinguish between samples with density differences as small as 0.0002 g/cm3
• Provides values that can be entered into a searchable database
• Does not require expensive instrumentation, a source of electrical power, or a highly-trained operator
• Is readily calibrated with a series of density standards
Additional Information
Intellectual Property Status: Patent(s) pending
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Inventor(s):
Blackledge, Robert D.
Lockett, Matthew R.
Mace, Charles R.
Mirica, Katherine A.
Whitesides, George M.
Categories:
For further information, please contact:
Mick Sawka, Director of Business Development
(617) 496-3830
Reference Harvard Case #4100