In these Science Notes I am presenting some of my current interests, activities, and thoughts, along with revisitations of a few of my past interests and related intriguing scientific questions. From time to time I will revise and add to these notes. 

One of the most perplexing problems in the current technological age is the lack of comprehension of effects of low-level radiation on the well being of living systems. I had an early involvement in this subject beginning with my studies of cancer and leukemia in the fifties and sixties. I did my Ph.D. research at the University of Texas, Austin, where Muller discovered the mutagenic effect of X-irradiation. His apparatus was displayed in the hall of the Experimental Science Building where I did my research, and where colleagues were continuing studies on drosophila and fungus mutations induced by irradiations. I continually fought with fruit flies for my lunch, and many of my tissue cultures were invaded by fungal spores prevalent in the building. I assisted fellow researchers in studies of effects of gamma radiation on plant cells. Needless to say, I was deeply impressed by the extensive knowledge of the mutagenic effects of various types of radiation. Later, in 1968, when I was team-teaching in biochemistry at the University of Oklahoma School of Medicine, I was taken by surprise by the respected radiologist member of the team when he rose to tell the class that I was wrong when I quoted studies indicating that the relationship between cumulative radiation dose and cancer incidence could be linear for humans. He assured the class that a minimum threshold dose was definitely required to cause cancer in human beings. Now, over 30 years later, this argument is still going on. Very few doubt the effect of larger radiation doses in causing cancer and leukemia death, and other health effects. However, many of those who would promote use of nuclear power generation argue against the linear relationship, while those opposing nuclear power and nuclear weapons and their related wastes argue in favor of the linear relationship, especially for in-utero exposures. Some feel that the effect of low doses may be even greater than that predicted by the linear theory, while their opponents may even favor the theory that low doses are beneficial (hormesis). The former will argue that any dose, no matter how small, poses a statistical risk, while their opponents will call any exposure below set limits completely safe.

I believe that it will probably be impossible to escape this quandary. Radiation from natural sources affects us all. We are all different from each other in our responses, and we probably even differ from our own selves at various ages and states of well-being. To top this off, we are bombarded by environmental stresses (differing from one small region to another) that cause many of the same unfortunate diseases that radiation can cause, and many of these disease states are inherent in the unique genetic framework of many of us. Statistically, there is a tremendous noise level in any attempted correlations (or non-correlations) of radiation effects with low-level doses. We may never reach agreement on such correlations. This becomes a real problem for policy makers who want scientists to be able to make definite 'best estimate' proclamations on such safety issues. I argue that we need to err on the safe side in cases (worst-case scenarios) where we do have a choice to make the risk as low as reasonably achievable. Where we have to make the decision between alternatives, then we do have to use fair and wise best estimates. Unfortunately, lawmakers will continue to have to make these decisions with bad science advice in many cases and jurists will continue to be required to determine damage cases fairly where science is still uncertain. Erroneous policy decisions about radiation releases can result in deaths, illnesses, and birth defects for generations, but decisions have to be made - just as for food and drugs, highway safety, public health, law enforcement, and national defense.

February 27, 1999

Science Note No. 2:  The Ranque-Hilsch Vortex Tube

This is a Ranque-Hilsch tube that I built for study.  Some of my students at the University of Calgary in 1978 had become interested in the Ranque-Hilsch phenomenon after reading an article about it in Scientific American and wanted to build a demonstration model for an open house demonstration.  We built a tube, and it was a very successful demonstration of the Ranque-Hilsch vortex separation, in which air forced tangentially into the tube next to an orifice between the two parts is separated into two flows out the ends, one very hot and the other very cold (down to as low as -70 °C).  In helping the students, I found that the separation effects were not completely understood, even though they were first reported by Ranque in 1933 and had been studied extensively in many laboratories around the world.  Using the tube illustrated above (transparent through the length), as well as others of varying geometries, I showed that the extreme temperature separation in the high-velocity vortex flow is realized at a point where a pair of vortices are formed and high-frequency sound is emitted.  I reported this, along with effects of two-phase flow in the tubes, in a joint ASME/AIChE meeting in 1979.  These effects are important in understanding vortex flow in general, and specifically as related to tornadoes, jet and rocket behavior.  They have yet to be explained.

January 24, 2002

Ph.D., Chemistry, University of Texas, Austin, 1962

Teaching experience in Chemical Engineering at the University of Texas (Austin), Oregon State University, University of Calgary, University of California (Berkeley),Brigham Young University; Chemistry at Lamar State University, and Biochemistry at University of Oklahoma School of Medicine.

Industrial and consulting experience (partial list): Mobil Oil Company, Mobil Chemical Company, ,Westinghouse Hanford Company, Stone & Webster Engineering Company, U.S. Department of Energy (nuclear waste) , M.W. Kellogg Company, Canadian and American oil and gas companies and chemical and safety consultants.

PUBLICATIONS:

McDuffie, N.G. "Ammonia Adsorption at the Aqueous Interface." Langmuir 17: 5711-5713. (2001)

McDuffie, N.G. "Comments on the paper 'Carbonated water: The physics of the cycle of bubble production' by S F Jones, K P Galvin, G M Evans and G J Jameson." Chem. Eng. Sci. 54: 1155. (1999).

McDuffie, N.G., Flammable Gas Tank Safety Program: Data Requirements for Core Sample Analysis Developed Through the Data Quality Objectives (DQO) Process, WHC-SD-DQO-004, Rev. 1. Richland, Washington: Westinghouse Hanford Co. for the U.S. Dept. of Energy. (1995)

Ashby, E.C., Annis, A., Barefield, E.K., Boatright, D., Doctorovich, F., Liotta, C.L., Neumann, H.M., Konda, A., Yao, C.F., Zhang, K., and McDuffie, N.G., Synthetic Waste Chemical Mechanisms, WHC-EP-0823. Richland, Washington: Westinghouse Hanford Co. for the U.S. Dept. of Energy. (1994).

McDuffie, N.G., "Flammable Gas Generation, Retention, and Release in High-Level Waste Tanks: Physical and Chemical Models," in Waste Management '94 (WM'94), ed. by R.G. Post as Proceedings of the Symposium on Waste Management, Tucson, 1994. Tucson, AZ: Laser Options, Inc. (1994).

McDuffie, N.G. Bioreactor Design Fundamentals. Stoneham, MA: Butterworth/Heinemann Publishers (1991).

Parsons, R.V., McDuffie, N.G., and Din, G.A., "pH Inhibition of Yeast Ethanol Fermentation in Continuous Culture," Biotechnology Letters 6: 677-80 (1984).

McDuffie, N.G., "Thermal Cracking Furnace," Module E5.1 in AIChEMI Modular Instruction, Series E: Kinetics, ed. by B.L. Crynes and H.S. Fogler (New York: American Institute of Chemical Engineers, 1984), pp. 1-11.

McDuffie, N.G., "Multicomponent Separations -- Lewis-Matheson," Module B2.6 in AIChEMI Modular Instruction, Series B: Stagewise and Mass Transfer Operations, Vol. 2: Multicomponent Distillation, ed. by J.M. Calo and E.J. Henley (New York: American Institute of Chemical Engineers, 1981), pp. 30-35, 69, 70.

McDuffie, N.G., "Batch Distillation, "Module B1.5 in AIChEMI Modular Instruction, Series B: Stagewise and Mass Transfer Operations, Vol. 1: Binary Distillation, ed. by E.J. Henley (New York: American Institute of Chemical Engineers, 1980), pp. 22-26, 93.

McDuffie, N.G., "Selectivity of Platinum and Platinum-Nylon Catalysts," Journal of Catalysis 57: 193-194 (1979).

Hancock, R.L., McDuffie, N.G., and Sinclair, D.B., "Theoretical Mechanisms for Synthesis of Carcinogen-Induced Embryonic Proteins: IV. The Viruses," Medical Hypotheses 5: 383-402 (1979).

McDuffie, N.G., "Resonance in the Ranque-Hilsch Vortex Tube," Preprint and presentation at the National Heat Transfer Conference of ASME and AIChE in San Diego, August, 1979 (ASME Publication 79-HT-16).

McDuffie, N.G., Letter to Editor re C₃ hydrocarbon vapor-liquid equilibrium and distillation, AIChE J. 24: 559-60 (1978).

McDuffie, N.G., "Vortex Free Downflow in Vertical Drains," AIChE J. 23: 37-40 (1977).

McDuffie, N.G., Letter to Editor re above publication and introducing mathematical model for choked vertical and radial inflow now included in Perry's Handbook, AIChE J. 23: 615 (1977).

McDuffie, N.G., "Lithium Permanganate Fixation of Mammalian Cells and Viruses for Electron Microscopy," Journal de Microscopie 19: 197-200 (1974).

McDuffie, N.G., "Crystalline Patterns in Auer Bodies and Specific Granules of Human Leukocytes," Journal de Microscopie 6: 321-30 (1967).

McDuffie, N.G. "Nuclear Blebs in Human Leukaemic Cells," Nature 214: 1341-42 (1967).

McDuffie, N.G. "Small Particles Associated with Pox Viruses," Journal of Bacteriology 85: 713-15 (1963).

McDuffie, N.G., "Comparison of Mouse Mammary Tumors Fixed with KMnO₄ and with OsO₄," Virology 18: 501-503 (1962).

McDuffie, N.G., Gibson, B.S., and Taylor, A., "Study of Toxic Factors Associated with Mouse Mammary Carcinomas in Egg Cultures,: Cancer Research 20: 1631-35 (1960).

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