Temperature dependence of the microwave properties of aqueous solutions of ethylene glycol between +15 degrees C and -70 degrees C. |
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| Authors: | J D Macklis F D Ketterer E G Cravalho |
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| Institution: | 1. Cryogenic Engineering Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 U.S.A.;2. Harrison Department of Surgical Research and the Department of Electrical Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 U.S.A.;3. Matsushita Professor of Mechnical Engineering in Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 U.S.A. |
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| Abstract: | The values of the dielectric constant and of the loss tangent for samples of 0 m (distilled H2O), 1 m, 2 m, 3 m, 4 m, 5 m, 10 m, and 100% ethylene glycol were determined over the temperature range of +15 °C to ?70 °C. An operating frequency of 1.40 GHz to 1.55 GHz was used, allowing the results to be applied directly to both 0.915 GHz and 2.450 GHz studies. Strong temperature and concentration dependencies were found; low concentration solutions tended to behave similarly to water, while higher concentration solutions were more independent. Peak values and discontinuities occurred at different temperatures, depending on concentration. Five molar ethylene glycol was indicated as a near optimum concentration based on toxicity, cryoprotection, and microwave power absorption considerations. A study of blends of cryoprotectants is suggested. |
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| Keywords: | Address reprint requests to Prof E G Cravalho Room 16-520 M I T Cambridge MA 02139 |
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