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.
Ultrasonic Cavitations and Precision Cleaning CREST ULTRASONICS
rently in great demand and is expected to increase in the future. The rapid advancements in various current technologies and the constant trend in miniaturizing of components have created a need for higher cleanliness levels. Contamination in the level of monolayers can drastically alter surface properties such as wettability, adhesion, optical or electrical characteristics. Particles in the range of few microns down to submicron levels, trace contaminants such as nonvolatile residues (NVR) in the range of micrograms/cm2 and pictogram/cm2, ionics in the same range or traces of corrosion have become part of the daily concerns of the manufacturing engineers in major industries such as semiconductors, automotive, disk drive, optics, ophthalmic, glass, medical, aerospace, pharmaceuticals and tool coatings, among others. The specifications on trace contaminants and particle sizes are being tightened periodically to reflect the new technology trends. Every industry has its own set of cleanliness specifications and the focus differs. For example, while NVR has not been an automotive industry issue until now, it has been crucial for the semiconductor and the disk drive industries for years. Trace contaminants are not acceptable in the carbide, optics and ophthalmic industries, as they may cause adhesion failures in a multi-coating process that follows cleaning. For obvious reasons, absolutely clean surfaces are an extremely critical requirement in cleaning medical devices. Concern about particles has become a common denominator among all industries.
Tortuosity or aneurysm? The palaeopathology of some abnormalities of the vertebral artery
The anatomy of the vertebral artery (VA) and two pathological conditions which affect it—tortuosity and aneurysm—are described. The changes which these lesions produce in the cervical vertebrae are also described and we present two cases in which these changes have been found. One case is of a female aged at least 45 years at the time of death from a 15th century medieval cemetery site in Britain with what we consider to be tortuosity of the VA. The second case is of a male aged between 25 and 35 years at the time of death from a Coffin period site in Japan, dating to ca 1600 years BP. The changes in this skeleton are considered to be more in keeping with a diagnosis of aneurysm of the VA. Copyright © 2002 John Wiley & Sons, Ltd.