Selective Gas Chromatographic Detection of Vapor-Phase Organics in Ambient Air

Vapor phase lubrication (VPL) integrates media lubrication with the vacuum processing steps used throughout most of the hard disk media fabrication process. This avoids exposure of the unlubricated a-CHx overcoat surface to the ambient air and airborne contamination. In vapor lubrication the a-CHx surface can be oxidized under controlled conditions immediately prior to lubricant adsorption. The kinetics of a-CHx oxidation have been studied using x-ray photoemission spectroscopy in an apparatus that allows oxidation of freshly deposited a-CHx films. The dissociative sticking coefficient of oxygen is ∼10−6 and the initial oxidation kinetics can be described by a Langmuir-Hinshelwood mechanism.

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Vapor Phase Lubricant Adsorption on Magnetic Data Storage Media

World Tribology Congress III, Volume 1 ◽

10.1115/wtc2005-64341 ◽

2005 ◽

Author(s):

Yang Yun ◽

Andrew J. Gellman

Keyword(s):

Data Storage ◽

Vapor Phase ◽

Ambient Air ◽

Magnetic Data ◽

Vapor Phase Lubrication ◽

Storage Media ◽

Airborne Contamination ◽

Hydrogenated Amorphous ◽

Processing Steps ◽

Vapor Lubrication

Vapor phase lubrication (VPL) integrates media lubrication with the vacuum processing steps used throughout most of the hard disk media fabrication process. This avoids exposure of the unlubricated hydrogenated amorphous carbon (a-CHx) overcoat to the ambient air and airborne contamination. In vapor lubrication the a-CHx surface can be oxidized under controlled conditions immediately prior to lubricant adsorption. The interaction between lubricants and a-CHx films can be tailored by controlled oxidation of the a-CHx in vapor phase lubrication.

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Ultratrace determination of vapor-phase nitrogen heterocyclic bases in ambient air

Analytical Chemistry ◽

10.1021/ac00246a015 ◽

1982 ◽

Vol 54 (9) ◽

pp. 1515-1518 ◽

Cited By ~ 27

Author(s):

Jeanette. Adams ◽

Elliot L. Atlas ◽

Choo Seng. Giam

Keyword(s):

Vapor Phase ◽

Ambient Air ◽

Heterocyclic Bases ◽

Nitrogen Heterocyclic

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The mutagenicity of HPLC-separated vapor-phase and particulate organics in ambient air

Atmospheric Environment Part A General Topics ◽

10.1016/0960-1686(92)90378-x ◽

1992 ◽

Vol 26 (13) ◽

pp. 2463-2466 ◽

Cited By ~ 15

Author(s):

William P. Harger ◽

Janet Arey ◽

Roger Atkinson

Keyword(s):

Vapor Phase ◽

Ambient Air

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Development of a Rapid Survey Method of Sampling and Analysis for Asbestos in Ambient Air

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096400 ◽

1972 ◽

Vol 30 ◽

pp. 630-631 ◽

Cited By ~ 2

Author(s):

R. E. Heffelfinger ◽

C. W. Melton ◽

D. L. Kiefer ◽

W. M. Henry ◽

R. J. Thompson

Keyword(s):

Neutron Activation ◽

Ambient Air ◽

Survey Method ◽

Potential Hazard ◽

Transmission Microscopy ◽

Comparative Analyses ◽

Asbestos Fibers ◽

Controlled Conditions ◽

Unequivocal Identification ◽

Identification And Quantification

A methodology has been developed and demonstrated which is capable of determining total amounts of asbestos fibers and fibrils in air ranging from as low as fractional nanograms per cubic meter (ng/m3) of air to several micrograms/m3. The method involves the collection of samples on an absolute filter and provides an unequivocal identification and quantification of the total asbestos contents including fibrils in the collected samples.The developed method depends on the trituration under controlled conditions to reduce the fibers to fibrils, separation of the asbestos fibrils from other collected air particulates (beneficiation), and the use of transmission microscopy for identification and quantification. Its validity has been tested by comparative analyses by neutron activation techniques. It can supply the data needed to set emissions criteria and to serve as a basis for assessing the potential hazard for asbestos pollution to the populace.

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Planar defects in ordered (Ga,In)P

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106570 ◽

1988 ◽

Vol 46 ◽

pp. 902-903

Author(s):

S. McKernan ◽

C. B. Carter ◽

D. Bour ◽

J. R. Shealy

Keyword(s):

Electron Diffraction ◽

Vapor Phase ◽

Growth Direction ◽

High Density ◽

Ordered Structure ◽

Planar Defects ◽

Diffraction Patterns ◽

Ternary Semiconductors ◽

Anion Species ◽

Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

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Application of Electron Optics to Characterization of Particulate Pollutants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009508x ◽

1972 ◽

Vol 30 ◽

pp. 364-365

Author(s):

J. B. Moran ◽

J. L. Miller

Keyword(s):

Air Quality ◽

Quality Standards ◽

Ambient Air ◽

Hazardous Substances ◽

Fuel Additives ◽

Ambient Air Quality ◽

Air Quality Standards ◽

Emission Standards ◽

Stationary Sources ◽

Ambient Air Quality Standards

The Clean Air Act Amendments of 1970 provide the basis for a dramatic change in Federal air quality programs. The Act establishes new standards for motor vehicles and requires EPA to establish national ambient air quality standards, standards of performance for new stationary sources of pollution, and standards for stationary sources emitting hazardous substances. Further, it establishes procedures which allow states to set emission standards for existing sources in order to achieve national ambient air quality standards. The Act also permits the Administrator of EPA to register fuels and fuel additives and to regulate the use of motor vehicle fuels or fuel additives which pose a hazard to public health or welfare.National air quality standards for particulate matter have been established. Asbestos, mercury, and beryllium have been designated as hazardous air pollutants for which Federal emission standards have been proposed.

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Electron Microscopic Characterization and Quantitation of Air Borne Particulate Matter with Special Emphasis on Asbestos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095042 ◽

1972 ◽

Vol 30 ◽

pp. 356-357

Author(s):

Peter K. Mueller ◽

Glenn R. Smith ◽

Leslie M Carpenter ◽

Ronald L. Stanley

Keyword(s):

Electron Microscopy ◽

Light And Electron Microscopy ◽

Ambient Air ◽

Quality Standard ◽

Primary Objective ◽

Cellulose Ester ◽

Main Concept ◽

Electron Microscopic ◽

Air Samples ◽

Diffraction Patterns

At the present time the primary objective of the electron microscopy group of the Air and Industrial Hygiene Laboratory is the development of a method suitable for use in establishing an air quality standard for asbestos in ambient air and for use in its surveillance. The main concept and thrust of our approach for the development of this method is to obtain a true picture of fiber occurrence as a function of particle size and asbestos type utilizing light and electron microscopy.We have now available an electron micrographic atlas of all asbestos types including selected area diffraction patterns and examples of fibers isolated from air samples. Several alternative approaches for measuring asbestos in ambient air have been developed and/or evaluated. Our experiences in this regard will be described. The most promising method involves: 1) taking air samples on cellulose ester membrane filters with a nominal pore size of 0.8 micron; 2) ashing in a low temperature oxygen plasma for several hours;

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