Robert E. Pellenbarg

Silicones as tracers for anthropogenic additions to sediments

Abstract Polyorganosiloxanes (silicones) have been measured in the sediments of the New York Bight. Range: 50 ppm organic silicon, dry weight basis, to below detection limit. Silicones are 37.9% silicon. Silicones correlated well ( r > 0.90) with other organic constituents in the same sediment samples which have been used to characterize sewage inputs to the sediments. Silicones are offered as a totally synthetic, specific, chemical tracer for anthropogenic additions to the environment.

Database tomography for technical intelligence: Comparative roadmaps of the research impact assessment literature and the journal of the American Chemical Society

This paper shows how Database Tomgraphy can be used to derive technical intelligence from the published literature. Database Tomography is a patented system for analyzing large amounts of textual computerized material. It includes algorithms for extracting multi-word phrase frequencies and performing phrase proximity analyses. Phrase frequency analysis provides the pervasive themes of a database, and the phrase proximity analysis provides the relationships among the pervasive themes, and between the pervasive themes and sub-themes. One potential application of Database Tomography is to obtain the thrusts and interrelationships of a technical field from papers published in the literature within that field. This paper provides applications of Database Tomography to analyses of both the non-technical field of Research Impact Assessment (RIA) and the technical field of Chemistry. A database of relevant RIA articles was analyzed to produce characteristics and key features of the RIA field. The recent prolific RIA authors, the journals prolific in RIA papers, the prolific institutions in RIA, the prolific keywords specified by the authors, and the authors whose works are cited most prolifically as well as the particular papers/journals/institutions cited most prolifically, are identified. The pervasive themes of RIA are identified through multi-word phrase of the database. A phrase proximity analysis of the database shows the relationships among the pervasive themes, and the relationships between the pervasive themes and subthemes. A similar process was applied to Chemistry, with the exception that the database was limited to one years issues of the Journal of the American Chemical Society. Wherever possible, the RIA and Chemistry results were compared. Finally, the conceptual use of Database Tomography to help identify promising research directions was discussed.

Introduction, Physical Properties, and Natural Occurrences of Hydrate

In the early 1820’s, John Faraday, working in England, was investigating the newly discovered gas, chlorine. He easily repeated the earlier experiments of Humphrey Davy (Davy, 1811) in which gaseous chlorine and water formed solid chlorine hydrate upon cooling in the “- late cold weather -”. Faraday’s lab curiosity chlorine hydrate has water as the host molecule, and chlorine molecules as the guest. These pioneering syntheses experiments are the first reported reference to a class of associative compounds now known as gas hydrates (Faraday, 1823, wvusd. 2000). Chlorine hydrate has persisted as a laboratory curiosity (Pauling et al., 1994) in part because its ease of formation lends it to laboratory demonstration. A variety of other molecules can form hydrates specifically and a variety of clathrates in general. The non-bonding uniqueness of clathrates as “chemicals” has interested scientists for almost two centuries.

Silicones in Chesapeake Bay sediments

Abstract Sediment samples from the upper reaches to the mouth of the Chesapeake Bay were analysed for extractable organic silicon (silicone) content. Organic silicon in the sediments ranged from less than 0.2 to some 36 ppm, w/w. In general, silicone tended to accumulate in high depositional areas: the northern bay, and along the shores to the south. While present, anthropogenic inputs in terms of defined source were not clear. It appears that processes in the bay act to rapidly remove silicone from the water column, probably on a function of the flocculation/precipitation of seston, especially in the northern area.

On Spartina alterniflora litter and the trace metal biogeochemistry of a salt marsh

Abstract The trace metals copper, nickel, zinc, manganese and iron, as associated with the aqueous surface microlayer retained on fallen Spartina alterniflora litter were studied in spatial and seasonal contexts. The metals were operationally defined as acetone soluble (organically associated), exchangeable, oxide ( Fe Mn ) associated, and total. Over 95% of all metals studied in two Delaware salt marshes were associated with the exchangeable and oxide classes. There was observed major spatial and seasonal variability in metal retention by the litter. Thus, litter some 12 m from tidal creek banks in the marsh was highest in metal content, which apparently reflects differences in the amounts of metal-rich microlayer reaching the litter with tidal water movements into litter-covered areas. Also, litter exhibited highest absolute quantities of trace metals studied in the winter season. This seasonal accumulation is biologically mediated, as sulphate reduction in anoxic marsh sediments releases H+ in the spring/summer and fall. The H+ released lessens retention of metals, especially iron, by the recumbent litter. For both marshes, and all seasons studied, the litter exhibited the following ranges in total metal content (dry weight basis): copper: 0·5–11 ppm; nickel: 2–11 ppm; zinc: 12–80 ppm; manganese: 40–350 ppm; iron: 1600–8100 ppm. The existence of two distinct chemical and physical types of microlayer in the salt marsh is reported. One is a ubiquitous, opaque brown, organic rich microlayer, the other, of more limited appearance, a thin, glassy, bluish-black material. The biogeochemical significance of both microlayer types is discussed, especially as the glass-like microlayer appears to result from oxidation of ferrous iron released from underlying anoxic sediments on a seasonal basis.

Historical record of silicones in sediment

Abstract Poly(organo)siloxanes (silicones) are totally synthetic polymeric materials that have seen increasing use since the Second World War. The use of silicones results in the release of these stable polymers to the environment, and data are presented which show measurable silicone (ppm level) in selected aquatic sediments. Presented also is a new, sensitive method for measuring silicone by use of chloroform extraction of a small (1 g or less) sample coupled with FTIR. Using this method silicone is detected in a sediment column at a depth which corresponds to the onset of the widespread use of silicones (ca. 1945). Thus, in very old sediment, there is no anthropogenic silicone, but contemporary surficial sediments exhibit silicone.

Trace metal partitioning in the aqueous surface microlayer of a salt marsh

The trace metals copper, cadmium, lead, iron, and zinc were studied in the microlayer of a Delaware salt marsh. Freeze-dried microlayer samples were extracted with organic solvents of differing polarity. The majority (approximately 95%, excluding cadmium) of trace metals in the microlayer could not be extracted with any of the organic solvents used, and are presumed associated with the inorganic phases of the microlayer. For organic-solvent-recoverable metals, acetone extracted the largest proportion of those metals. Portions of the work reported here strongly suggest that humic-like materials sequester the organically soluble metals in the salt marsh surface microlayer.

Control of Gas Hydrate Formation Using Surfactant Systems: Underlying Concepts and New Applications

Abstract: We describe some new approaches to the rapid formation of gas hydrates using surfactant systems that form reverse micelles. The thermodynamics of hydrate formation in surfactant containing reverse micellar systems indicate the possibility of controlling hydrate deposition. The use of reverse micellar systems also allows the deposition of hydrates in the form of small crystallites that do not aggregate. Surfactants also appear to displace agglomerated hydrates from surfaces, thereby facilitating flow. Direct injection of water into gas saturated liquid hydrocarbons leads to rapid hydrate formation. On the other hand, water droplets injected into liquid carbon dioxide indicate a gradual conversion to the hydrate form with the initial formation of a hydrate skin. An interesting application of rapid hydrate formation is its use in the restriction of inorganic nanocluster growth.

Methane Hydrate Fuel Storage for All-Electric Ships: An Opportunity for Technological Innovation

Abstract: New industrial processes for forming methane hydrate, combined with the knowledge that small changes in gas hydrate‐forming mixtures can greatly expand the pressure‐temperature field of hydrate stability, suggest that virtually solid gas hydrates can be formed and stored in fuel tanks of any shape at near sea level ambient conditions. Development of this technology may allow a gas hydrate fuel transport medium to be devised and applied. Reduction‐to‐practice of this special fuel storage medium could have a significant impact upon the design and engineering of future Navy vessels and concurrently upon the future of naval operations.

LIQUID PHASE OXIDATION OF HEXYLDISULFIDE BY t-BUTYL HYDROPEROXIDE IN BENZENE

ABSTRACT There are inconsistencies in the literature regarding the role of organosulfur compounds in general, and sulfonic acids in particular, on the oxidative instability of middle distillate fuels. Comparison of published results between investigations is complicated by differences in a large number of variables. Variations in fuel composition, heteroatam distribution, reaction surface, hydroperoxide concentration, dissolved oxygen and reaction temperature all contribute to the variation in observed results. In an effort to clarify this situation, we have examined the t-butyl hydroperoxide liquid phase oxidation of hexyldisulfide in deaerated benzene.