In this Issue:
Photographs taken at the November SAS Meeting (click the mouse on the photo for a larger image):
As we prepare for the upcoming year of meetings of the Baltimore-Washington section of the Society for Applied Spectroscopy , there are a wide variety of opportunities open to the section. These include outreach to the community, outreach to the federal, state, and local governments, supplying direction to the local society, and supplying direction to the Society for Applied Spectroscopy as a whole. These may seem to be grand goals, but we are in a unique position to put the variety of expertise in the society to good use.
At the community level, there are many opportunities to make a difference. These range from working as a judge at a Science Fair at local schools, being a guest speaker at a local school to provide insight to students, faculty, and parents into the varied roles of scientists. Writing a letter to the local school board , PTA or other organizations on topics of your expertise to interpret the huge amount of data from various sources that flood organizations. I have been involved, to a limited degree in several issues in the Howard County Maryland PTA, investigations of chemistry related issues, providing direction in the investigations. Often a trained scientific perspective is required, and not available.
The legislative bodies in this country have often responded to scientific issues without adequate scientific basis. We, as scientists have the ability to make a difference in issues being addressed by our governments. This can be as simple as making a phone call, sending an e-mail, or as involved as you are inclined to be. As the chairman of the Baltimore-Washington section of the SAS, I feel that I can speak for the remainder of the officers in saying that you can make a difference in the local section of the SAS. At present, I know I can use or need assistance in determining the direction, focus, and content of the meetings, as well as determining the direction, to the extent of my abilities, of the future of the section. As a delegate to the national meetings of the Society for Applied Spectroscopy, you can make your ideas for the society heard at a national level. This year we did not have any delegates sent to the national meeting at the FACSS conference. This can and should change.
It is a good bet that I have not had the opportunity to meet or speak with you. I am relatively new to the community and there are a large number of the members of the Baltimore-Washington Section that I have not met. If you haven't made it to the meetings recently, take an evening to come to come to one of the meetings, for a nominal cost, you can come, talk to some interesting people in similar and different fields, and hear an interesting bit of science. If there is some other reason that you don't come to the meetings, please let me know. If the cost of the meals is keeping you away, keep in mind that the speaker eats for free, and often gets to pick the location of the meeting and a date convenient to him/her. If you do not want to be the speaker, you can recommend people whom you would like to hear from, or topics that you would like to hear about.
I do not expect that I will receive a deluge of e-mails, phone calls and letters, but I hope that I hear from some of you, even if it is only to complain about the cost of gasoline, or the location of the section meetings. You can contact me by e-mail at John.S.Canham.1@gsfc.nasa.gov or canham@erols.com, You can call me at work 301-286-8970, at home 410-480-2472. You can also write me at 2717 Brinkleigh Dr., Ellicott City, MD 21042.
John S. Canham, Chairman
Date: Wednesday November 15, 2000
Place: West End Grill, 7904 Woodmont Ave., Bethesda, MD, 301-951-9696
Time: 6 pm Social Hour, 7 pm Dinner, 8 pm Seminar.
Cost: $20 -Choice of Pasta Entrees (You may choose at the restaurant) or Choice of: 1) Chicken Taverna (Chicken breast with eggplant, zucchini, tomato and cheese), 2) Grilled Salmon, or 3) Shrimp Francaise. Included with each meal is a House Salad, Coffee, Tea, or Soft Drink and Dessert.
Reservations: Please make your reservations by NOON, Monday, November 13, 2000 by calling John Canhan at work 301-286-8970 . IF YOU RESPOND VIA E-MAIL, FOR THIS MEETING PLEASE SEND ELECTRONIC RSVP's TO: john.s.canham.1@gsfc.nasa.gov.
Directions: From the Beltway take Wisconsin Ave. south past NIH. Take
a right turn on Woodmont Ave. Restaurant is after the 4th light. Use street
parking or the parking garage on the right in the next block.
Abstracts of Presentations
Simulation of Droplet Heating and Desolvation in an Inductively Coupled Plasma
Craig M. Benson, Sergey F. Gimelshein, Deborah A. Levin, and Akbar Montaser.
Dept. of Chemistry, The George Washington University, Washington, DC 20052
The total desolvation rate of sample droplets in an argon inductively coupled plasma (Ar ICP) is investigated through the development of a two-phase flow computer model using the direct simulation Monte Carlo(DSMC) method. Particle evaporation equations are used to obtain desolvation rates for droplets under a variety of initial conditions. The desolvation model is supplemented by equations used to determine the trajectories of particles through the plasma. The model is used to calculate the behavior of aerosol droplets from a direct injection high efficiency nebulizer (DIHEN), a micronebulizer used to inject microliter quantities of samples that are toxic, expensive, or of limited volume. Although our primary objective has been to model the behavior of droplets from the DIHEN, the methodology is more general and can be applied to more rarefied flow conditions such as particle contamination in space plumes. We use the combination of desolvation and transport models to present the first predicted spatial distribution of droplet concentrations and evaporation rates in an ICP flow. This data is compared with the behavior of a DIHEN spray in an environment with no net argon gas flow to determine the importance of gas flow rates to overall droplet concentration profiles in the ICP. In addition, two separate techniques for determining droplet trajectories are contrasted.
Craig M. Benson is a student at The George Washington University in Washington, DC. He holds a B.A. in Chemistry from Brandeis University in Massachusetts and anticipates finishing his Ph.D. in Physical Chemistry in June 2001. His past and present research interests, in addition to ICP-MS studies, have included synthesis and characterization of organonickel dimers that contain metal centers with different coordination numbers, determination of absolute lifetimes of atmospheric contaminants via UV absorption studies and subsequent computer modeling, and he has studied fluorinated compounds using IR line broadening to determine exact global warming potentials.
Langmuir Probe Measurements of Plasma Properties in a Free-Running Helium
Inductively Coupled Plasma
Craig S. Westphal, Akitoshi Okino, Lisa A. Iacone, Michael G. Minnich, Qun Jin,
Hironobu Yabuta, and Akbar Montaser.. Dept. of Chemistry, The George Washington
University, Washington, DC 20052
A strong secondary discharge is observed at the mass spectrometer interface
when helium inductively coupled plasmas (He ICPs) are used as ionization sources
for mass spectrometry (MS). To reduce the ion kinetic energies and plasma potential,
a free-running He ICP was developed for mass spectrometry. In this system, a
balanced plasma can be obtained by adjustment of the center capacitor plate
of the air capacitor located in the tank circuit of the generator. The effect
of RF input power, capacitor plate position, and probe location on the plasma
properties are examined. Electron temperature increases with RF input power
from 400 W to 800 W. Measured electron temperature values range from 6,100 to
11,600 K and from 4,900 K to 8,900 K with the 13- and 18-mm torch, respectively.
Measured electron number density values range from 1.1 x 1014 cm-3 to 1.6 x
1014 cm-3 and from 0.5 x 1014 cm-3 to 1.4 x 1014 cm-3 for plasmas in a 13- and
18-mm torch, respectively. The electron temperature of the He ICP at a capacitor
plate setting of 0 mm (minimal secondary discharge in Ar ICPMS) is approximately
1.5 times greater than a setting (capacitor plate position = -11 mm) that offers
minimal secondary discharge in He ICPMS. Relatedly, electron number density
values in the He ICP at a capacitor position of 0 mm are 8 to 10 times greater
compared to those measured at a capacitor plate position of -11 mm. Measured
electron temperature values are also compared with the calculated local thermodynamic
equilibrium (LTE) values.
Student Speakers
Craig S. Westphal is also a student at The George Washington University
in Washington, DC. He holds a B.A. in Chemistry from Wittenberg University,
Springfield, Ohio and anticipates finishing his Ph.D. in Analytical Chemistry
in May 2004. In addition to the work he will be describing in his presentation,
he has investigated and synthesized CB11H12- for potential use with boron neutron
capture therapy, determined uranium levels and isotopic ratios in synthetic
urine using the Large Bore-Direct Injection High Efficiency Nebulizer (LB-DIHEN),
and been involved in the development of interfaces for coupling several chromatographic
systems (capillary electrophoresis (CE), multicapillary-CE (MC-CE), gas chromatography
(GC)) with ICP-MS.
Download the linked PDF of the newsletter .
Your Baltimore-Washington Section Officers for 1999-2000:
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Links to other local scientific organizations:
Chemical
Society of Washington, CSW, Local Section of the American Chemical Society
Past Issues of the Baltimore-Washington Section Newsletter (including Historical Events in Chemistry for those months)
October and November Historical Events in Chemistry and Spectroscopy by Leopold May, Department of Chemistry, Catholic University
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