Download or read book Thermal and Chemical Fog Dissipation written by Bruce A. Kunkel and published by . This book was released on 1973 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of thermal and chemical fog dispersal tests, conducted by AFCRL during July 1972, are presented and discussed. Forty-three tests were conducted in fog, thirty-three of which were suitable for analysis. Ninety-six additional heat tests were conducted in clear air. Two wide-area urea seeding tests were also performed. An instrumented 200-ft tower, a lidar, and a ground network of visibility sensors and droplet sampler were used to monitor the effects of the tests on the foggy environment. The seeding tests were unsuccessful. Improper execution of the wide-area seeding pattern due to a lack of knowledge of the winds at the seeding location was responsible for the failure of the seeding tests. (Modified author abstract).
Download or read book Thermal and Chemical Fog Dissipation written by Bruce A. Kunkel and published by . This book was released on 1973 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of thermal and chemical fog dispersal tests, conducted by AFCRL during July 1972, are presented and discussed. Forty-three tests were conducted in fog, thirty-three of which were suitable for analysis. Ninety-six additional heat tests were conducted in clear air. Two wide-area urea seeding tests were also performed. An instrumented 200-ft tower, a lidar, and a ground network of visibility sensors and droplet sampler were used to monitor the effects of the tests on the foggy environment. The seeding tests were unsuccessful. Improper execution of the wide-area seeding pattern due to a lack of knowledge of the winds at the seeding location was responsible for the failure of the seeding tests. (Modified author abstract)
Download or read book Fog Modification written by Bernard A. Silverman and published by . This book was released on 1973 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report is a comprehensive review of fog modification. It includes discussions of the physical structure and climatological characteristics of various types of fog. The three different methods of fog modification, that is, removal, evaporation and prevention are discussed, as are the general requirements of fog dispersal. In depth descriptions are given of the techniques used to modify supercooled, warm, and ice fog. (Author).
Download or read book The Air Quality and Noise Impact of a Warm Fog Dispersal System Using Momentum Driven Heat Sources written by Bruce A. Kunkel and published by . This book was released on 1976 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of a Warm Fog Dispersal System (WFDS) on the air quality and noise level is assessed. The WFDS, designed by AFGL, uses various combinations of heat and thrust to disperse the fog over the runway and approach zones. Emission and noise levels that are within the state-of-the-art are used in this assessment. Calculations show that within the cleared area the pollution concentrations, on the average, are within the EPA standards. (Author).
Download or read book On the Local Dissipation of Natural Fog written by Henry G. Houghton and published by . This book was released on 1938 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is submitted that the hazards of landing aircraft in fog could be greatly reduced by providing relatively small clearings into which approaching planes could be safely guided by radio or other navigational aids which are now available. The same general method might also be used to facilitate the entrance of ships into fog-bound harbors or docks. In the first section of this paper the properties of fog which are of importance in the discussion of methods of fog dissipation are summarized on the basis of measurements made at Round Hill. The minimum dimensions of a cleared space of useful size are taken as 500 to 1000 meters long, 30 to 50 meters wide and 10 to 20 meters high. From extensive investigations at Round Hill it is known that in order to maintain a clearing of this size under typical wind conditions, fog must be cleared at a minimum rate of about 2000 cubic meters per second. This figure is used for all subsequent computations. It is pointed out that the known methods of fog dissipation can be divided into two general classifications: (i) those in which the fog particles are physically removed from the air, and (2) those in which the particles are evaporated in the air. Numerous specific methods are then described and critically examined with respect to their ability to provide cleared air at a rate of 2000 cubic meters per second in a reasonably practical manner. The more important methods considered involve the use of intense sound fields, charged or uncharged falling particles, electrical precipitation, mechanical precipitation, evaporation by heating and evaporation induced by the condensation of atmospheric water vapor on hygroscopic particles. It is concluded that the evaporation methods as a class are superior to the physical removal methods because they lower the relative humidity of the cleared air and thereby greatly reduce the limiting effects of atmospheric turbulence which act to "fill in" the cleared space. The method involving the condensation of water vapor by means of calcium chloride is chosen as being probably the most practical of the fog dissipation methods considered. The second section of the paper presents a detailed examination of one application of the calcium chloride method of fog dissipation. In this method drops of a saturated solution of calcium chloride are released above the volume of fog which is to be cleared. These hygroscopic drops, which are large enough to fall fairly rapidly, condense a sufficient quantity of water vapor from the air through which they descend to effect the evaporation of the fog particles. The investigation of this method of fog dissipation is divided into three parts. The first part deals with the determination of the relative humidity required to cause the evaporation of the fog drops as a function of the time of evaporation and the size of the fog drops. The second part is concerned with the rate of condensation of water vapor on drops of calcium chloride solution as a function of the drop size and concentration. In the third part the criteria for the selection of the optimum size of the solution drops are presented and the development of spray nozzles capable of forming drops of approximately the desired size is described briefly. Finally, the quantity of calcium chloride solution required for the dissipation of fog under typical conditions is computed. It is found that, with the best available spray nozzles, fog can be dissipated at a rate of 2000 cubic meters per second (sufficient to maintain a cleared space of useful size under typical conditions) by spraying from 4 to 5 liters of saturated solution per second. It is concluded that the method is practicable on the scale proposed. The third section of the paper is an account of the design and successful operation of a full sized experimental fog dissipater operating according to the method described in the second section. The major considerations which influenced the determination of the size and spraying capacity of the apparatus are summarized and the essential features of the actual installation are described. The test procedure is outlined and the average results of eight successful tests conducted during a period of two and one-half years are indicated. The tests were made at air temperatures ranging from 4° to 20° C and at wind velocities up to 7 meters per second. The clearings formed were usually from 500 to 700 meters long, 30 to 50 meters wide and 15 to 20 meters high. After the installation of an improved type of spray nozzle clearings of the same size were maintained by spraying only 5 liters of saturated calcium chloride solution per second. The data obtained in two typical fog dissipation tests are presented in detail. It is found that the experimental results are in excellent agreement with the computations presented in the second section of the paper. It is concluded that the local dissipation of natural fog by means of sprayed calcium chloride is entirely feasible. Certain practical disadvantages of the experimental installation are discussed and a new type of apparatus which has recently been constructed to overcome some of these limitations is briefly described. Methods for practically eliminating the corrosive action of the calcium chloride solution are also noted. The fourth and final section of the paper, describes a new type of apparatus in which the general method of fog dissipation by means of hygroscopic particles is applied in a different manner. By substituting finely-divided calcium chloride powder for the relatively coarse spray it is possible to confine the hygroscopic material entirely within the dissipating apparatus which is constructed in the form of a short tunnel. The spent hygroscopic material is removed from suspension by means of a special eliminator and only cleared and dehumidified air is discharged. A powerful engine-driven blower facilitates proper distribution of the cleared air under all wind conditions. The advantages of this type of apparatus in comparison with that described in the third section are: the absence of an external spray of calcium chloride, its independence of wind velocity over a considerable range, and its smaller size which reduces the obstruction hazard and permits it to be made mobile. From the results of tests with the spray-type fog dissipater it was known that the new apparatus should be capable of reducing the relative humidity to 90% in 2000 cubic meters of fog per second in order to maintain a clearing of useful dimensions under typical conditions. A unit of excessive size would be required to handle this quantity of air. However, it is possible to remove a sufficient quantity of water vapor from a fraction of the air so to that the required relative humidity of 90% can be produced in the total volume of air by proper admixture of the dried portion. A commercial calcium chloride powder was selected as the most suitable hygroscopic material and computations were made to determine the quantity of powder required and the time necessary for it to act. In order to check these computations, which involved several simplifying assumptions, and also to develop the essential features of the proposed apparatus, a working model was set up outdoors. Results from the tests with the model are in fairly good agreement with the computations. It was determined that the lowest practical exit relative humidity is about so%. Since a relative humidity of 90% suffices for the dissipation of fog only one-fifth of the total volume of air to be cleared need be handled by the apparatus on this basis. The eliminator which mechanically removes the spent calcium chloride particles from the dehumidified air is an important part of the apparatus. After numerous tests on typical eliminators it was found necessary to develop a new type which would be effective at the required high flow velocities. The important problem of properly distributing the dried air was studied with the aid of a large mobile blower unit. It was concluded that, although it would be preferable to employ a number of appropriately spaced discharge ports when possible, a satisfactory distribution could be effected from a single large opening by using a discharge velocity of from 20 to 30 meters per second. Preliminary designs for two units of the new type are presented to show that the size, weight, blower power requirements and quantity of calcium chloride required for apparatus capable of maintaining cleared spaces of useful size are not unreasonable
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 1134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Fog Challenges and Advancements in Observations Modeling and Forecasting written by Darko Koračin and published by Springer. This book was released on 2017-01-28 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the history of marine fog research and applications, and discusses the physical processes leading to fog's formation, evolution, and dissipation. A special emphasis is on the challenges and advancements of fog observation and modeling as well as on efforts toward operational fog forecasting and linkages and feedbacks between marine fog and the environment.
Download or read book Summary Report written by and published by . This book was released on 1968 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ENVPREDRSCHFAC Technical Paper written by Environmental Prediction Research Facility (U.S.) and published by . This book was released on 1974 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Warm Fog Dissipation Heat Source Program Fort Rucker Alabama April 1969 written by E. M. Frisby and published by . This book was released on 1970 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report gives an account of a short field program on warm-fog dissipation conducted at Fort Rucker, Alabama, in April 1969. The program objective was to establish the effective sphere of influence of the heat plume generated by two specific types of a heating unit. Results of the experiments led to the postulation of the type of equipment needed to clear a Minimum Helicopter Landing Zone of fog. The report discusses the detailed conduct of each experiment and represents an analysis of the daily observations obtained between 19 and 27 April 1969. (Author).
Download or read book Project Fog Drops Investigations of warm fog properties written by Roland J. Pilié and published by . This book was released on 1972 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR Cumulative Index of Research Results written by United States. Air Force. Office of Aerospace Research and published by . This book was released on 1963 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Meteorological and Geoastrophysical Abstracts written by and published by . This book was released on 1976 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fixing the Sky written by James Rodger Fleming and published by Columbia University Press. This book was released on 2010-09-02 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: As alarm over global warming spreads, a radical idea is gaining momentum. Forget cuts in greenhouse gas emissions, some scientists argue. Instead, bounce sunlight back into space by pumping reflective nanoparticles into the atmosphere. Launch mirrors into orbit around the Earth. Make clouds thicker and brighter to create a "planetary thermostat." These ideas might sound like science fiction, but in fact they are part of a very old story. For more than a century, scientists, soldiers, and charlatans have tried to manipulate weather and climate, and like them, today's climate engineers wildly exaggerate what is possible. Scarcely considering the political, military, and ethical implications of managing the world's climate, these individuals hatch schemes with potential consequences that far outweigh anything their predecessors might have faced. Showing what can happen when fixing the sky becomes a dangerous experiment in pseudoscience, James Rodger Fleming traces the tragicomic history of the rainmakers, rain fakers, weather warriors, and climate engineers who have been both full of ideas and full of themselves. Weaving together stories from elite science, cutting-edge technology, and popular culture, Fleming examines issues of health and navigation in the 1830s, drought in the 1890s, aircraft safety in the 1930s, and world conflict since the 1940s. Killer hurricanes, ozone depletion, and global warming fuel the fantasies of today. Based on archival and primary research, Fleming's original story speaks to anyone who has a stake in sustaining the planet.
Download or read book Weather Modification written by United States. Environmental Data Service and published by . This book was released on 1978 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OAR Cumulative Index of Research Results written by and published by . This book was released on with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interaction of a Buoyant Turbulent Round Jet with a Co flowing Wind written by Milton M. Klein and published by . This book was released on 1975 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: A broad effort is being conducted to develop an operational Warm Fog Dispersal System (WFDS) using ground-based heat sources. In order to determine the optimum heat and thrust for the combustors in the WFDS, investigations have been made of the buoyant motion in round- and plane-heated turbulent jets in co-flowing (that is, same direction) wind fields. This report describes a method of calculating the round jet case. The method can be used for jet velocities of 100m/sec or less, wind velocities below or equal to the jet velocity, and jet temperatures up to 3 times the ambient value. Initial jet velocities of 5 and 20m/sec and temperature excesses, relative to the ambient temperature, of .3 and 1 were selected for the calculations.
