Aqueous And Semi -Aqueous Alternatives For CFC-113 And Methyl Chloroform Cleaning Of Printed Circuit Board Assemblies
l ICOLP is the Industry Cooperative for Ozone Layer Protection. ICOLP corporate member companies include AT&T, Boeing Company. We would like to thank the many individuals and companies that provided insight and information that helped produce this manual. ii iii Disclaimer The U.S. Environmental Protection Agency (EPA), the Industry Cooperative for Ozone Layer Protection (ICOLP), the ICOLP committee members, and the companies that employ the ICOLP committee members do not endorse the cleaning performance. worker safety, or environmental acceptability of any of the technical options discussed. Every cleaning operation requires consideration of worker safety and proper disposal of contaminants and waste products generated from the cleaning processes. Moreover, as work continues. including additional toxicity testing and evaluation under Section 612 (Safe Alternatives Policy) of the Clean Air Act Amendments of 1990 and elsewhere, more information on the health, environmental. and safety effects of alternatives will become available for use in selecting among the alternatives discussed in this document. EPA and ICOLP, in furnishing or distributing this information, do not make any warranty or representation, either express or implied, with respect to its accuracy. completeness, or utility; nor does EPA and ICOLP assume any liability of any kind whatsoever resulting from the use of, or reliance upon, any information. material, or procedure contained herein, including but not limited to any claims regarding health, safety, environmental effects or fate, efficacy, or performance. made by the source of the information. Mention of any company or product in this document is for informational purposes only, and does not constitute a recommendation of any such company or product. either express or implied by EPA, ICOLP. ICOLP committee members, and the companies that employ the ICOLP committee members.
Terpene cleaning of electronic assemblies
The technology and methods developed to safely spray the semi-aqueous terpene hydrocarbon Bioact EC-7 are described. This technique is used to remove rosin-based solder paste residues after reflow soldering of surface-mount devices to printed circuit board assemblies. The operating experience gained during the implementation of this semi-aqueous terpene hydrocarbon cleaning method is described. >
Geographic And Environmental Influence On Maya Settlement Patterns Of The Northwest Yucatan: An Explanation For The Sparsely Settled Western Cenote Zone
Most settlement pattern research and GIS analysis of the ancient Maya of the Northern Yucatan have focused on water availability in a dry landscape where cenotes are often the only water source. While water is of paramount importance, permanent settlement secondarily requires farmable soil, a resource often as precious as water in many parts of the Yucatan. The dynamics between these resources reveal areas of ideal settlement and more challenging landscapes for which the Maya developed strategies to overcome environmental conditions. A region of the southwest "Cenote Zone", however, appears to have presented the ancient Maya with insurmountably poor environmental conditions despite abundant water resources. The lack of dense population and stone architecture in this area emphasizes the lack of a simple correlation between cenotes and settlement. This thesis uses GIS analysis to identify and explore such problematic settlement areas to better understand the factors and complexities involved in the more successful settlements of neighboring regions. iv This work is dedicated to my late father, who first introduced me to the Mundo Maya through a visit to the ruins of Tikal at the age of nine, and who instilled in me strength, curiosity, and a love for exploring the world. v ACKLOWLEDGEMENTS I'd like to acknowledge Dr. Arlen Chase and Dr. Diane Chase for providing such outstanding opportunities and instruction, and for leading by example both in the field and in the classroom. Dr. John Walker for his eye-opening perspectives, GIS instruction, inspiring hard-working attitude, and patience in the field. Dr. Clifford Brown and Dr. Walter Witschey for their invaluable correspondence and for their contributions to mapping and GIS data of Maya sites.