Showing papers on "Particulates published in 1977"
TL;DR: In this article, the authors used light and scanning electron microscopy to determine the size and morphological distributions of the particles in a profile from the upper 400m at 2°47'N, 8°51'W in the equatorial Atlantic by large volume in situ filtration.
437 citations
TL;DR: In this paper, vertical profiles of light scattering from over 1000 L-DGO nephelometer stations in the Atlantic Ocean have been used to calculate mass concentrations of suspended particles based on a calibration from the western North American Basin.
298 citations
TL;DR: Analysis of suspended particulate matter larger than 1 micrometer, filtered from thousands of liters of surface and deep waters during GEOSECS expeditions to the Atlantic and Pacific oceans, have provided new information on the nature and time scales of chemical processes associated with the particles.
Abstract: Analyses of suspended particulate matter larger than 1 micrometer, filtered from thousands of liters of surface and deep waters during GEOSECS expeditions to the Atlantic and Pacific oceans, have provided new information on the nature and time scales of chemical processes associated with the particles. Trace element and radionuclide data show that particles scavenge trace elements such as Th, Pu, Fe, Pb, and Cu from the ocean column, thereby controlling their concentrations. For other elements, however, particles are a source: carbon and silicon, for example, are introduced at depths as sinking particles dissolve. Studies of both particulate concentrations by filtration of seawater and particulate fluxes by using sediment traps seem necessary to delineate the intricate nature of chemical processes in the oceans.
146 citations
Patent•
09 May 1977TL;DR: In this paper, an absorbent article such as a diaper or a sanitary napkin is made up of a facing sheet, a absorbent pad, and a moisture-impervious backing sheet, which contains a particulate, water-insoluble but water-swellable polymeric absorbent.
Abstract: An absorbent article such as a diaper or a sanitary napkin is made up of a facing sheet, an absorbent pad means, and a moisture-impervious backing sheet. The absorbent pad means comprises a fibrous structure having an intermediate densified layer and a layer of highly porous, loosely compacted batt on both sides of the densified layer. The batt layer between the densified fibrous layer and the moisture-impervious backing sheet contains distributed therein a particulate, water-insoluble but water-swellable polymeric absorbent.
142 citations
TL;DR: In this paper, the concentrations of 18 trace elements in freshly released faecal pellets, moults and eggs from a representative planktonic crustacean were reported, indicating the importance of these particulates in oceanic trace element biogeochemical cycles.
Abstract: IT has become increasingly evident that biogenous processes in oceanic surface layers play an important role in removing trace elements from sea water and transporting them to the sediments1,2. Plankton are strongly implicated in these processes and investigations of the chemistry of these organisms have demonstrated their ability to accumulate trace elements to relatively high levels3,4. Zooplankton metabolic activity can be expected to enhance the biogeochemical cycling of trace elements through the release of particulate matter3 such as faecal pellets, moulted exoskeletons and eggs. Furthermore, theoretical models5,6 on the vertical flux of particulates have emphasised the sinking of large particles, similar to those produced by zooplankton, as a mechanism for rapid transport of particulate matter and associated trace elements out of the mixed layer. Nevertheless, little, if any, data exist on (the trace element composition of these biogenic particles, and Boyle et al.7, interpreting their Pacific Ocean Cd profiles in terms of probable Cd regeneration from sinking biogenic debris, have stressed the need for information on the trace element composition of planktonic particulate matter. This note reports the concentrations of 18 trace elements in freshly released faecal pellets, moults and eggs from a representative planktonic crustacean. The high levels of many trace elements found in these biogenic products, relative to concentrations in the plankton which produce them, clearly indicate the importance of these particulates in oceanic trace element biogeochemical cycles.
142 citations
TL;DR: In this article, organic carbon (OC) was determined in atmospheric particulate matter collected at several remote marine locations in the northern and southern hemispheres (Bermuda, Hawaii, Samoa).
Abstract: Organic carbon (OC) was determined in atmospheric particulate matter collected at several remote marine locations in the northern and southern hemispheres (Bermuda, Hawaii, Samoa). The OC concentrations were rather similar at all three locations, generally ranging from 0.2 to 0.4 µg/m³ STP. The major mass of the OC at all three locations was found on the smallest particles (radii less than 0.5 µm). However, the major mass of OC on laboratory generated atmospheric sea salt particles was found on particles with radii from 1-3 µm, the same size as the major mass of the sea salt in both the laboratory experiments and in ambient marine air. This suggests that most of the organic material in marine atmospheric particulate matter is not associated with sea salt. Gas-particle interactions involving organic compounds could explain the observed size distribution of the OC-containing particles and the rather constant concentrations of organic carbon found in marine atmospheric particulate matter at the locations studied.
107 citations
TL;DR: In this article, the feasibility of characterising particulate pollutants by means of Raman spectroscopy has been investigated and the results indicate that physical structures similar to activated carbon are at least a major species and may be the dominant species in both source-enriched and ambient samples.
Abstract: AIRBORNE particulates have a major role in the air pollution problem. They are responsible for acid rain, reduced visibility, and, in certain size ranges, are deposited in the lungs where they can cause various disorders. Considerable effort has been expended in the analysis of these particulates using techniques such as wet chemistry, X-ray fluorescence, infrared spectroscopy and ESCA. Yet there are still great uncertainties as to the chemical form and origin of many of the particulate species. We describe here preliminary studies of the feasibility of characterising particulate pollutants by means of Raman spectroscopy. We believe that this is the first attempt to apply this spectroscopic technique in this area of research. The samples studied included diesel exhaust particles, automobile exhaust particles (unleaded fuel, no catalytic converter) and several ambient air samples. The spectra from these samples were compared with those of polycrystalline graphite and activated carbon which were used as references. Our results indicate that physical structures similar to activated carbon are at least a major species and may be the dominant species in both source-enriched and ambient samples. The implications of this observation could be quite important in terms of atmospheric chemistry, health effects, weather modifications and the effects of aerosols on the albedo.
103 citations
93 citations
86 citations
TL;DR: From February to June, 1975, primary production in the eastern part of the southern North Sea was 90 to 120 g C·m−2, except for the area close to the Rhine outflow, where more organic matter was consumed by heterotrophs than was produced by algae in the first months of the growing season.
79 citations
TL;DR: In this paper, a vertical flux model was constructed which showed atmospheric input of trace metals to the Sargasso Sea to be of the same approximate magnitude as the rate of removal of PTM from the mixed layer by sinking in association with POC.
TL;DR: Documentary evidence for the changes in the air pollutant levels and climate of London are compared with the results obtained from a simple single box model for the annual mean SO2 and particulate levels in the London air.
TL;DR: In this article, the relationship between the nitrate and sulfate content of photochemically formed aerosol particles which were produced by exposing initially particle-free ambient air in a 14 m3 transparent Teflon chamber to sunlight with various amounts of NO2, SO2, and C3H6 added to the reaction mixture was observed.
TL;DR: In this article, two types of glass fiber filters in widespread use were found to collect 10-20 times as much artifact nitrate as actual particulate nitrate, and the severity of the interference under ambient sampling conditions was evaluated.
TL;DR: A sampling program using high-volume filter samples for studying the concentration and composition of particulate matter in the arid southwest (in and near Tucson, Ariz.) was established in January 1974 as mentioned in this paper.
Abstract: A sampling program using high-volume filter samples for studying the concentration and composition of particulate matter in the arid southwest (in and near Tucson, Ariz.) was established in January 1974. Through the use of statistical techniques and examination of enrichment factors, it is possible to make a number of suggestions regarding the sources for and the cycle of various species in the desert rural and urban atmosphere. Large particle airborne soil or crustal materials dominate the aerosol population found in both the urban and rural atmosphere with over a dozen of the measured species directly attributable to this source. Nonsoil species, in general, appear to be fairly well mixed and probably result primarily from nonurban anthropogenic and natural sources. The acid-base nature of airborne gases and particles would appear to control the gas and particle distribution of ammonia and to largely define the particulate sulfate speciation (primarily (NH/sub 4/)/sub 2/SO/sub 4/). Large seasonal fluctuations, consistent with the climatology and meterology for the area under investigation, are seen in the concentration and composition of particulate matter in the desert atmosphere.
TL;DR: In this article, the presence and nature of high molecular weight organic matter in seawater was reviewed and its biogeochemical cycle was discussed, and it was shown that macromolecular organic matter is refractory to bacterial attack.
TL;DR: In this article, the authors present an outline of the kinds of research required to support or reject the hypothesis that urban woody plants are important air filters, and discuss some scanning electron microscope observations of the particulate burden on leaves of London plants.
Abstract: This paper reviews the various lines of evidence that support the hypothesis that above-ground plant parts remove particulates from the atmosphere. Some scanning electron microscope observations of the particulate burden on leaves of London planetree are discussed. The authors present an outline of the kinds of research required to support or reject the hypothesis that urban woody plants are important air filters.
TL;DR: In this paper, suspended particulate matter was collected by filtration on 0.4-µm Nucleopore filters on a series of six stations along the axis of the Laurentian Trough.
Abstract: PARTICULATE matter in the waters of the Gulf of St Lawrence, a major marginal sea, contains as much as 16,500 p.p.m. manganese. This is comparable with the levels of manganese found in deep-sea sediments1. Here we show that it is possibly a related phenomenon. Suspended particulate matter was collected by filtration on 0.4-µm Nucleopore filters on a series of six stations along the axis of the Laurentian Trough. The samples were digested in a Teflon bomb with a mixture of aqua regia and hydrofluoric acid, and analysed by atomic absorption spectrophotometry2. Figure 1 shows a typical vertical profile of the concentration of suspended particulate matter and its content of manganese. The manganese content increases rapidly with depth to a maximum value of 16,500 p.p.m. at 40–120 m above the bottom. The profiles are similar for the two cruises.
TL;DR: In this article, gas chromatography-mass spectrometry with computerized data acquisition was used to detect aliphatic and polyaromatic hydrocarbons, fatty acids and heterocyclic arenes.
TL;DR: An intensive field sampling program has been carried out over the ocean in which 56 gas samples and 172 aerosol particle samples were analyzed for total organic chlorine and total inorganic chlorine gas and for particulate chlorine as a function of particle size as mentioned in this paper.
Abstract: An intensive field sampling program has been carried out over the ocean in which 56 gas samples and 172 aerosol particle samples were analyzed for total organic chlorine and total inorganic chlorine gas and for particulate chlorine as a function of particle size. Sampling was conducted for 13- to 21-hour periods, March 5–14, 1976, 4 km from the north Florida shore of the Gulf of Mexico at 10-m and 2-m heights. Replicate samples collected simultaneously showed agreement within analytical errors generally of a few percent for gases and for the sum of particle size fractions. Over the course of the experiment, 21 ambient measurements of organic chlorine averaged 3050 ng Cl/m3 STP of air, with a standard deviation of the distribution of measurements of 80 ng Cl/m3 STP. Also in 21 measurements the sum of particulate and inorganic chlorine averaged 3030±190 ng Cl/m3 STP. Thus the total chlorine concentration observed averaged 6070±220 ng Cl/m3 STP, of which 50% was organic gaseous. In contrast, the proportion of inorganic gaseous chlorine varied drastically, ranging from one half to one hundred times the observed particulate chlorine concentration. The variation depended at least in part on whether cascade impactors with Nuclepore backup filters or filters alone were used for particle sampling before the airstream passed through treated LiOH-impregnated gas absorption filters and charcoal absorbers. The results suggest that rapid interchange occurs between inorganic gaseous and particulate chlorine in the atmosphere but that organic gaseous chlorine is relatively decoupled from these forms.
TL;DR: The methanol extraction from particulates collected on glass fiber filters appears to be effective for collections of both aliphatic and polycyclic aromatic compounds and organic acids.
TL;DR: In this article, the major organic constituents of airborne particulate matter are determined by Soxhlet extraction with benzene and methanol, which is performed by the internal standard technique using a mass chromatographic approach.
TL;DR: In this paper, a system was developed for collecting kilogram quantities of size-fractionated particulate matter which can be subsequently used for biologic testing purposes, including fly ash from stack gas passed through the electrostatic precipitator of a coal-fired power plant.
Abstract: A system is developed for collecting kilogram quantities of size-fractionated particulate matter which can be subsequently used for biologic testing purposes. The apparatus consists of a series of two cyclones and a centripeter and yields four size fractions. When used over a 12-day period to classify fly ash from stack gas passed through the electrostatic precipitator of a coal-fired power plant, the collected fractions have volume median diameters of 20, 6.3, 3.2, and 2.2 ..mu..m with geometric standard deviations of approximately 1.8. A total of 8.08 kg of fly ash is collected.
Patent•
12 Dec 1977TL;DR: In this article, a continuous process for recovery of values from a solid carbonaceous material is described, in which carbon is pyrolyzed in the presence of a particulate source of heat.
Abstract: In a continuous process for recovery of values from a solid carbonaceous material, the carbonaceous material is pyrolyzed in the presence of a particulate source of heat to yield a particulate carbon containing residue of pyrolysis and volatilized hydrocarbons while simultaneously the volatilized hydrocarbons are hydrogenated. The particulate source of heat is formed by oxidizing carbon in the solid residue to heat the particles. Hydrogen for hydrogenation is obtained by reacting at least a portion of the hot particulate carbon containing residue of pyrolysis with steam prior to feeding the hot particulate residue to the pyrolysis reaction zone. Steam and/or carbon dioxide can be introduced into the pyrolysis reaction zone to react with carbon containing residue contained therein. The particulate source of heat can be introduced to the pyrolysis reaction zone over an overflow weir. The hydrogen and the particulate source of heat can be formed simultaneously in an oxidation-conversion zone. The volatilized hydrocarbons can be further hydrogenated in a vapor hydrogenation zone.
Dissertation•
03 May 1977
Patent•
07 Oct 1977
TL;DR: In this article, solid and/or dissolved contaminants are separated from a polar liquid such as water by providing in the contaminated liquid medium a galvanically charged particulate dispersion of defined size, concentration, density and free surface energy.
Abstract: Solid and/or dissolved contaminants are separated from a polar liquid such as water by providing in the contaminated liquid medium a galvanically charged particulate dispersion of defined size, concentration, density and free surface energy, and then flowing such loaded medium through successive treatment zones of an electrically insulated apparatus at a rate defined by dimensionless parameters such as Reynolds Numbers so as to prevent phase separation. Gaseous oxygen adheres to particle surfaces and oxidation is further promoted by bringing medium to pH 2.0 to 2.5 as with sulfur dioxide gas, plus exposure to action of heavy-metal ions such as ferrous/ferric. After air blowing, medium is neutralized and brought to pH 10-11 with continuous aeration of suspended flocculant, then treated with soda ash and optionally additional particulate (recycled sludge), and the contaminant matter then allowed to precipitate with concurrant galvanic grounding of the medium. The dispersed particulate matter may be inert and deliberately added (e.g. shredded cellulose) or it may be produced in situ by fractionation of component debris as in sewage-refuse; in the latter case the particle itself is subsequently oxidized. In either event, dual end products are potable water and sterile sludge. Dissolved salts such as sodium chloride are simultaneously removed from medium as component of sludge; applicable to remove toxic components from cooling water systems, recover traces of precious metals, etc. from slurry or run-off liquid, brackish water, industrial waste, etc.
TL;DR: In this article, a steady state, three-dimensional solution of the atmospheric diffusion equation including settling, deposition, and first-order removal is presented, applied to the prediction of airborne concentrations of gaseous and particulate pollutants.
Patent•
07 Dec 1977TL;DR: In this article, a continuous process for recovery of values from a solid carbonaceous material is pyrolyzed in the presence of a particulate source of heat, which is formed by oxidizing carbon in the solid residue to heat the particles.
Abstract: In a continuous process for recovery of values from a solid carbonaceous material, the carbonaceous material is pyrolyzed in the presence of a particulate source of heat to yield a particulate carbon containing residue of pyrolysis and volatilized hydrocarbons while simultaneously the volatilized hydrocarbons are hydrogenated The particulate source of heat is formed by oxidizing carbon in the solid residue to heat the particles Hydrogen for hydrogenation is obtained by reacting at least a portion of the hot particulate carbon containing residue of pyrolysis with steam prior to feeding the hot particulate residue to the pyrolysis reaction zone Steam and/or carbon dioxide can be introduced into the pyrolysis reaction zone to interact with carbon containing residue contained therein The particulate source of heat can be introduced to the pyrolysis reaction zone over an overflow weir