Showing papers on "Particulates published in 1970"

Surface active organic material in the marine atmosphere

Abstract: Constituents of the marine atmosphere were collected on shallow trays exposed to onshore winds on the windward coast of the Island of Oahu. Upon addition of distilled water to the trays the collected materials formed organic monomolecular films on the water surface, and the curves for film pressure versus area for these films were determined at the field site. The monolayer studies indicated the presence of weakly surface-active organic compounds and hydrocarbons as well as strongly adsorbed, highly polar species. Simultaneous collections of oceanic particulate matter were made with a high-volume air sampler with glass fiber filters. The organic material was extracted from the filters with chloroform and analyzed for specific fatty acids by gas chromatography. The ratios of the quantities of the principal fatty acids found in the air samples were similar to previously reported fatty acid ratios from sea surface samples collected at the air-sea interface. It was concluded that the ocean appears to be a major source of airborne maritime organic matter. The implications of these data to sea fog and haze stabilization are discussed.

A Preliminary Evaluation of Atmospheric Pollution as a Cause of the Global Temperature Fluctuation of the Past Century

Abstract: Two globally extensive forms of atmospheric pollution (carbon dioxide and particulate loading) are each considered from the viewpoint of long-term changes in their world-average abundance, and the relevance of these to the observed fluctuation of planetary average temperatures in the past century.

The quantity, composition and distribution of suspended particulate matter in the Gulf of California

Abstract: The distribution and composition of suspended particulate matter in the sea is very complex and not well understood. In this study, 3 different approaches were used to estimate the quantity and quality of suspended particulate matter in 34 samples from the euphotic zone of 9 stations in the Gulf of California. The results from electronic, microscopic and chemical analyses showed that most parameters measured were significantly correlated, e.g. the total particulate volume from particles of 2 to 150 μ diameter, as obtained from the Coulter Counter, proved to be significantly related to such parameters as seston, particulate nitrogen, particulate carbon, phytoplankton carbon and chlorophylla. It can be concluded from this study that the Coulter Counter can be a very useful instrument to determine, with little effort, the size, distribution, and volume of particulate suspended matter in the sea. These data can then be used to calculate some important biological parameters which are necessary to establish meaningful models of phytoplankton production. More detailed studies are necessary to prove the above mentioned relationships in depth, space and time.

Characterization of particulate lead in vehicle exhaust-experimental techniques

Abstract: Experimental techniques and equipment required to provide representative samples of particulate matter from the exhaust of vehicles are considered. A system capable of sampling the exhaust from a vehicle under realistic operating conditions has been constructed. The vehicle is operated on a chasses dynamometer and controlled by magnetic tapes recorded on the road. The exhaust is diluted with air in a mixing tunnel and a near-proportional sample obtained using the variable dilution principle. During each run a number of samples are collected simultaneously to confirm the measurements made with different instruments, as well as to provide a mass balance. The sampling system can be used with a variety of instruments to characterize particulate matter emitted in the exhaust in terms of particle size, particle size distribution, physical structure, and composition. An exhaust filter has been developed to withstand exhaust gas temperatures, and is connected directly to the vehicle tail pipe. This filter has been shown to quantitatively collect exhaust lead compounds and thus provide the means to investigate the effect of vehicle characteristics and driving conditions on lead emissions. 13 references, 16 figures, 4 tables.

Atmospheric aerosol composition and concentration as a function of particle size and of time.

Abstract: As a step toward better understanding the reactive Los Angeles air basin atmosphere, a study was undertaken at the University of California—Riverside Campus, to determine the composition and concentration of atmospheric particulate matter as a function of particle size and time. The study involved developing a method for obtaining size-classified, time-fractionated aerosol samples amenable to chemical and physical (including microscopic) analysis. During a 15-day period, samples were obtained over 4-hr periods and subsequently analyzed for nitrate, sulfate, iron, and lead. Concentration of six gaseous pollutantsj total aerosol light-scattering, and several meteorological measurements were simultaneously recorded and averaged over the 4-hr intervals. This data was presented graphically to show the diurnal variation in and relationship between gaseous, particulate, and meteorological measurements. A strong relationship between gaseous peroxyacetyl nitrate, particulate nitrate, and aerosol light-scattering w...

Chemical changes involving nitrogen metabolism in water and particulate matter during primary production experiments

Abstract: The uptake of ammonia and nitrate by particulate matter during photosynthesis in large light and dark bottles was followed by colorimctric and mass spectromctric methods. Ammonia uptake as determined by tho 15N isotope was always higher than the parallel estimate from colorimctric analysis. The uptake (or release ) of ammonia in the dark was inversely related to the protein content of the corresponding sample of particulate matter. Utilization of nitrate in light was inversely proportional to the concentration of ammonia available, The p,articulate organic matter contained 50.5% protein in light bottles but 61.7% protein in dark ones. The mean ratio of oxygen changes, as calculated from changes jr-r protein, carbohydrate, and lipid to those found experimentally, was 1.03 in light bottles (indicating good agreement) and -0.34 in dark ones. This is interpreted as evidence for some particle formation in the dark that is probably not microbial.

Production of particulate organic matter by the reef on kavaratti atoll (laccadives)

Abstract: The concentration of particulate organic carbon in the vicinity of Kavaratti Atoll is much greater than that of the surrounding sea. The particulate organic matter, which is largely produced by the coral reef, amounts to about 20% of the total gross production of tho reef community. It is suggested that, in the absence of an adequate standing crop of phytoplankton, the particulate matter may form an important source of energy to zooplankton in coral reef waters.

Filtration of Treated Sewage Effluent

Abstract: Effluent used in this investigation was obtained from a pilot scale activated sludge treatment plant, operated at a solids retention time of ten days. Particulate matter in the effluent was characterized by measurement of suspended solids, particle size and distribution, and particle charge and charge distribution. Although a number of removal mechanisms are operative, straining was found to be the principal mechanism responsible for the removal of particulate matter. The size and distribution of the influent particles, their floc strength, the size of the medium, the filtration rate, and amount of material arrested within the filter must be considered in the development of equations which can be used to describe the time-space removal of particulate matter within a granular filter. Equations were developed to predict filter performance as a function of these variables for the conditions studied. These equations can also be generalized for cases where straining is not the principal removal mechanism.

Method for backwashing filters

Abstract: A vertical vessel has a filter bed disposed in its lower portion for normal filtering of solid particulates from contaminated liquid passed down through the bed. Vertical passages are formed to extend below the upper surface of the filter bed with a layer of smooth-surfaced bodies arranged to reduce the cross-sectional area of the vessel to impart desired velocity to the particulates in the liquid. Conduits are provided to flow liquid and gas up through the bed to backwash particulates from the bed into a collection above the bed which is removed by a siphon in a batch operation.

Apparatus for particulate coating of an elongate article

Abstract: A substantially closed shell contains an air pervious liner defining an inner chamber for coating an article with thermoadhesive particles. Air flowing continuously through the liner toward the article in the chamber prevents buildup of the thermoadhesive particles on either the top or sides of the chamber. The chamber may be formed with a pair of openings to permit the entry and exit of pipe to be coated.

Method and means to control air pollution from motor vehicles and motor vehicle engines

Abstract: AN ANTIPOLLUTANT DEVICE ASSOCIATED WITH A MOTOR VEHICLE TO CONTROL THE VEHICLE EMISSIONS TO ATMOSPHERE, NOT ONLY THE EMISSIONS FROM THE EXHAUST PORT OF THE MOTOR BUT ALSO FUEL AND OIL EVAPORATIVE EMISSIONS. THE EVAPORATIVE EMISSIONS ARE COLLECTED IN A COLLECTOR UNIT AND THE MOTOR EXHAUST PORT EMISSIONS FILTERED AND TREATED, AND PARTICULATE MATTER COLLECTED AND GASES BURNED.

Certain Aspects of Production and Standing Stock of Particulate Matter in the Surface Waters of the Northwest Atlantic Ocean

Abstract: Samples collected during January and October 1968 from 44° to 19°N in the western North Atlantic were analysed for particulate organic carbon, ATP, DNA, chlorophyll a, and total particulate volume between 1 and 40 μ diameter Although the ratio of chlorophyll to ATP decreased from north to south, the ratio of particulate carbon to ATP did not show any systematic trend A good correlation was found between ATP and DNA even though the DNA concentration was too great to be entirely representative of living material Growth or production of particulate material as measured by the Coulter Counter method was higher than that measured by C-14 method A trend was noted towards higher specific growth rate with smaller standing crop in southern waters

Method of controlling the emission of odors and particulate matter

Abstract: A method of controlling the emission of odors and particulate matter, for example, from a rendering and meat packing plant. The method comprises the steps of providing a source of gas, for example air, containing an undesirable level of odor and particulate matter, causing the gas to pass through a chamber containing a densely sprayed chemical solution which contacts the gas at a high contact efficiency between the gas and the liquid to collect and suspend particulate matter in the solution and absorb odors, and causing the gas again to be placed into forced intimate contact with the solution while simultaneously separating the chemical solution from the cleansed gas. The method may also include the step of creating a uniform gas velocity prior to treatment, and, in an alternate embodiment, the gas may be subjected to a plurality of spraying treatments with the same or different solutions. The solutions may be acidic, basic, masking, oxiodizing, neutralizing, or reacting. Specific solutions disclosed include solutions of water with sodium bicarbonate, sodium bisulfite, sodium hydroxide, chlorine dioxide, potassium permanganate, and calcium hypochlorite. Chlorine gas may also be introduced into the air stream for the same purpose.

Method and apparatus for sensing particulate matter

Abstract: A method and apparatus for sensing particulate matter in a fluid by application of an electrical field of sufficient potential to a flowing fluid so that a particle contained in the fluid causes an avalanche breakdown of the fluid dielectric. The breakdown rate is determined by the rate of particle flow through the field.

Carbon dioxide and its role in climate change

Abstract: Climate is variable. In historical times, many significant fluctuations in temperature and precipitation have been identified. In the period from 1880 to 1940, the mean temperature of the earth increased about 0.6?C; from 1940 to 1970, it decreased by 0.3-0.49C. Locally, temperature changes as large as 3-40C per decade have been recorded, especially in sub-polar regions. The cause of these changes has been under extensive study. One factor is the steady increase in carbon dioxide which has been observed, presumably as a result of the combustion of fossil fuels. In the late 19th century, prior to the industrial revolution, the carbon dioxide content of the atmosphere was about 290 ppm. This had risen to 314 ppm in 1960, and to just over 320 ppm in 1970. Aircraft observations by the Atmospheric Physics and Chemistry Laboratory of the Environmental Science Services Administration have clearly shown the importance of metropolitan areas as a source of carbon dioxide. The effect of carbon dioxide is to increase the earth's temperature by absorbing outgoing terrestrial radiation. Recent numerical studies have indicated that a 10% increase in carbon dioxide should result, on the average, in a temperature increase of about 0.30C at the earth's surface. The present rate of increase of 0.7 ppm per year would therefore (if extrapolated to 2000 A.D.) result in a warming of about 0.60C-a very substantial change. A second cause of climatic change is particulate loading of the atmosphere. Some meteorologists have attributed the cooling of the earth since 1940 primarily to such pollution of the atmosphere by man. However, the net effect of particulate matter on climate is difficult to analyze. Such pollutants, depending upon their size distribution and the elevation at which they occur, both intercept incoming solar radiation and trap outgoing radiation from the earth. The first process tends to depress the temperature of the earth's surface; the latter tends to increase it. To further complicate matters, the effect of pollution by natural volcanic activity must be considered. Unlike most activities of man, violent volcanic eruptions inject particulates directly into the stratosphere, where they are most effective in cooling the earth. The drop in the earth's temperature since 1940 has been paralleled by a substantial increase in natural volcanism. The effect of such volcanic activity is probably greater than the effect of manmade pollutants. Finally, the possibility of other factors in climatic change must be considered. Solar radiation may change slightly in intensity or wavelength distribution: other natural explanations have been suggested. Our measurements of radia-

Minor sources of air pollutant emissions.

Abstract: Emission source inventories for air pollutants have considered major categories such as transportation, domestic heating, electric power generation, refuse burning, industrial fuel consumption and process emissions, as well as commercial, institutional, and governmental space heat fuel burning. Not considered in such emission inventories are sources such as aerosol spray can, ground dust, leaf burning, cosmic dust, crop dusting, perfumes, smoking, marsh gas, and tire tread wear. This paper investigates and evaluates such minor emissions on a population density or land area basis. These minor pollutant sources have been overlooked in the past because of their assumed negligible emissions. It is shown, however, that minor sources of air pollutants normally not included in an emission inventory do contribute to the total pollution burden of an area. In areas where particulate emissions are important, natural sources of dust, sea salt, cigarette smoking, cigar smoking, spray can aerosol, foot wear use, and rubber from tire abrasion should be evaluated. In areas where photochemical air pollution is a major problem organic compounds from vegetation must be considered in the evaluation of the problem. Great strides have been made in the development of factors to be used in the calculation of air pollutant source emissionmore » inventories. It is suggested that emphasis should be also directed toward a more extensive study of minor sources of air pollutant emissions. 24 references, 1 table.« less

The nature of particulate matter

Abstract: The origin and the nature of particulate matter which is found in the earth's atmosphere, and which is measured to evaluate air pollution, are discussed. The importance of defining particulate matter in terms of its physical structure and its chemical composition is emphasized. Attention is drawn to the surface activity of particulate matter and it is shown that, because of its micropore fine structure and its content of metals, particulate matter may act as a catalyst for some reactions, and also as a carrier for any vapour and gas. Ammonia, hydrocarbons and nitrogen oxides, adsorbed on particulates, have been detected and determined. The compositions of both inorganic and organic fractions of particulates are discussed and a procedure for the systematic analysis of various classes of organic compounds is outlined. The results obtained by thin layer and gas chromatography to elucidate the composition of the organic fraction are

Preparation of finely particulate silicon oxides

Abstract: Finely particulate silicon oxides are produced from coarse particulate silicon dioxide using a liquid stabilized plasma burner. Hydrocarbons are used as the stabilizing liquid, and the coarse particulate silicon dioxide is reduced by the hydrocarbon plasma jet leaving the plasma burner, and a part of the hydrocarbon which is evaporated and decomposed in the arc zone is withdrawn together with the liquid hydrocarbon stabilizing medium, which is recycled, separated from the liquid, and used as carrier gas for feeding the coarse particulate silicon dioxide. Finely particulate silicon monoxide is initially formed, and may be recovered as such, or oxidized at the anode of the plasma burner to silicon dioxide.

Sterilizing separate compartments of particulate material

Abstract: THE SPECIFICATION DISCLOSES A METHOD AND APPARATUS FOR STERLIZING PARTICULATE SOLID MATERIAL SUCH AS MEAT CUBES OR BEANS. THE PARTICLES OF SOLID MATERIAL ARE POSITIVELY FED BY A CONVEYOR, SUCH AS A SCREW CONVEYOR, THROUGH A CHAMBER WITH AN ATMOSPHERE OF STEAM OR OTHER HEATING GAS, AND THE RESIDENCE TIME DETERMINED BY THE POSITIVE FEEDING IS SUCH AS TO ENSURE THAT THE REQUIRED TREATMENT IN THE CHAMBER IS COMPLETED.