Advances in Chemistry Series - American Chemical Society

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NUPRO Valves and Filters for Analytical Applications

SHUT OFF Compact valves for reliable flow regulation and shut off • stem threads removed from system fluid • compact designs • ball tip or regulating stems

Sources and Fates of Aquatic Pollutants

NUPRO Valves and Filters offer these design and performance choices: • End Connections: SWAGELOK® Tube Fittings, NPT, Tube Stub, Weld, CAJON VCO® & VCR®

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• Service Ratings: vacuum to 6000 psi; temperatures to 900 °F STOCKED FOR IMMEDIATE DELIVERY BY AUTHORIZED SALES AND SERVICE REPRESENTATIVES.

NUPRO®

NUPRO COMPANY 4 8 0 0 East 345th Street Willoughby, O H 4 4 0 9 4

A SWAGELOK® COMPANY

METERING

• quick-acting, 1/4 turn • full flow • easy maintenance

Valves for precise flow control in laboratory and instrument systems • accurate, repeatable flow adjustment with no initial surge • compact, low dead space • stem threads removed from system

FILTRATION Inline and tee type filters to protect instruments by removing hard particle contamination from fluid lines • choice of sintered and wire mesh elements from 0.5 to 440 microns • compact designs • all metal construction SWAGELOK - TM Crawford Fitting Company CAJON. VC0 & VCR - TM Caion Company C01986 SWAGELOK Co.. all rights reserved N-56ta

CHECK & RELIEF Relief valves open at pre-set pressure: check valves allow unidirectional flow control • cracking pressures 1/3 to 6000 psi • smooth floating poppet • positive back stop

n the past decade significant advances have occurred in our understanding of the processes controlling the transport and fate of inorganic and organic species in the limnic and marine environments. These processes can be studied by using a holistic approach in which the atmosphere, water, and sediment are considered interdependent compartments of an ecosystem. This new book presents this holistic approach and describes relationships between physical mixing rates and chemical reaction rates. Four sections are covered in this volume: • Air-Water Processes • Water Column Processes • Water-Sediment Processes • Case Studies The emphasis of the first three sections is on the chemical and physical processes controlling solute behavior and fate in air and water. The case studies integrate information on these processes into a systemwide picture of the cycling of inorganic and organic chemicals. Specific chapter topics include the following: • environmental modeling of hydrophobic compounds • air-sea transfer of trace elements • vapor-particle partitioning of semivolatile organic compounds • metal speciation in natural waters This volume will be useful for marine scientists, industrial chemists, atmospheric scientists and industrial chemists. Ronald A. Hites, Editor, Indiana University S. J. Eisenreich, Editor, University of Minnesota Developed from a symposium sponsored by the Division of Environmental Chemistry of the American Chemical Society Advances in Chemistry Series No. 216 576 pages (1987) Clothbound LC 87-1290 ISBN 0-8412-0983-9 US & Canada $99.95, Export $119.95 Order From: American Chemical Society Distribution Office Dept. 51 1155 Sixteenth St., N.W. Washington, DC 20036 or CALL TOLL FREE

800-227-5558 and use your credit card! CIRCLE 107 ON READER SERVICE CARD 482 A • ANALYTICAL CHEMISTRY, VOL. 60, NO. 7, APRIL 1, 1988