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Sample records for acid fog effects

  1. Acid fog

    SciTech Connect

    Hileman, B.

    1983-03-01

    Fog in areas of southern California previously thought to be pollution-free has been shown to have a pH as low as 1.69. It has been found to be most acidic after smoggy days, suggesting that it forms on the aerosol associated with the previously exiting smog. Studies on Whiteface Mountain in the Adirondacks show that fog water is often 10 times as acidic as rainwater. As a result of their studies, California plans to spend $4 million on acid deposition research in the coming year. (JMT)

  2. Effects of acid fog and ozone on conifers. Final report

    SciTech Connect

    Bytnerowicz, A.; Olszyk, D.M.; Takemoto, B.K.; McCool, P.M.; Musselman, R.C.

    1989-05-01

    This study evaluated the effects of acidic fog (pH 2.0, 3.0, or 4.0) on the physiological, biochemical, and growth responses of two coniferous tree species (Pinus ponderosa and Abies concolor), and determined if exposure to acidic fog predisposed the tree seedlings to the phytotoxic effects of ozone (O{sub 3}). Results provide evidence that the growth and metabolic responses of two coniferous tree species could be altered by multiple applications of acidic fog, and by exposure to ambient O{sub 3}. In general, the alterations were slight to modest, which may be attributed to the low degree of stress severity, and the slow rate of tree growth. The findings indicate that exposure to acidic fog followed by O{sub 3} does not cause detectable changes in conifer seedling growth within a single-growing season. Nevertheless, it is clear that acidic fog and O{sub 3} cause temporal alterations in seedling physiology and biochemistry.

  3. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    The chemical composition of fog particles has become of considerable interest, because of both the possibility of interpreting atmospheric- chemistry processes in fog particles in terms of the principles of aqueous chemistry and the potential health effects of species present in fog particles. The acidity of fog particles has received wide attention. This communication noted the actual magnitude of the excess acidity in acidic fog particles and suggested a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air. (DP)

  4. Effects of acid fog and dew on materials. Final report

    SciTech Connect

    Mansfeld, F.; Henry, R.; Vijayakumar, R.

    1989-10-01

    Field exposure tests have been carried out in order to separate the effects of acidic fog on materials damage from those caused by rain, dew and natural weathering. The test sites were McKittrick and Visalia in the Central Valley and West Casitas Pass in Ventura County. The field tests have been supported by laboratory tests in which materials damage has been determined during exposure to carefully controlled fog water chemistry. Analysis of the field exposure results for galvanized steel and the paint samples shows that the corrosivity of the atmosphere at the three test sites have been very low. The result is confirmed by the ACRM data which show very low corrosion activity. Since corrosion rates were so low approaching those for natural weathering, it was not possible to determine the effects of acidic fog. Based on the aerometric data and the observed corrosion behavior, it is doubtful that acidic fog conditions prevailed for significant times during the exposure period of 1/87 - 3/88 at Visalia and McKittrick. The results of the laboratory tests show that exposure to HNO3 at low pH and to high pollutant concentration increased the corrosion rate of galvanized steel to over 10 micro m/year. Exposure to HNO3 caused serious corrosion damage to anodized aluminum and the paint.

  5. Acute exposure to acid fog. Effects on mucociliary clearance

    SciTech Connect

    Laube, B.L.; Bowes, S.M. III; Links, J.M.; Thomas, K.K.; Frank, R. )

    1993-05-01

    Submicrometric sulfuric acid (H2SO4) aerosol can affect mucociliary clearance without eliciting irritative symptoms or changes in pulmonary function. The effect of larger fog droplets containing H2SO4 on mucociliary clearance is unknown. We quantified mucociliary clearance from the trachea (n = 4) and small airways (n = 7) of young healthy male adults after an acute exposure to H2SO4 fog (MMAD = 10.3 microns; pH = 2.0; liquid water content = 481 +/- 65 mg/m3; osmolarity = 30 mOsm). Acid fog (AF) or saline fog (SF) (10.9 microns; 492 +/- 116 mg/m3; 30 mOsm) was administered for 40 min of unencumbered breathing (no mouth-piece) at rest and for 20 min of exercise sufficient to produce oronasal breathing. Fog exposures were followed by a methacholine (MCh) challenge (a measure of airway reactivity) or inhalation of technetium-99M radioaerosol (MMAD = 3.4 microns) on 2 study days each. Changes in symptoms and forced ventilatory function were also assessed. Clearance was quantified from computer-assisted analyses of gamma camera images of the lower respiratory tract in terms of %removal/min of the radiolabel from the trachea 25 min after inhalation and from the outer zone of the right lung after 1.9 to 3 h. Symptoms, forced ventilatory function, and MCh response were unaffected by either fog. Tracheal clearance was more rapid in four of four subjects after AF (0.83 +/- 1.58% removal/min) compared with that after SF (-0.54 +/- 0.85% removal/min). Outer zone clearance was more rapid in six of seven subjects after AF (0.22 +/- 0.15% removal/min) compared with that after SF (0.01 +/- 0.09% removal/min).

  6. Quantity of acid in acid fog

    SciTech Connect

    Deal, W.J.

    1983-07-01

    This communication notes the actual magnitude of the acidity in acidic fog particles and suggests a possible line of inquiry into the health effects of such fog so that it can be determined whether a typical fog is detrimental or beneficial relative to dry air.

  7. Acute exposure to realistic acid fog: Effects on respiratory function and airway responsiveness in asthmatics

    SciTech Connect

    Leduc, D.; De Vuyst, P.; Yernault, J.C.

    1995-11-01

    The biological effects of acid fog composed primarily of ammonium ions and sulfate are described. Subjects with asthma were exposed for one hour to sulfuric acid aerosol. Significant changes were not observed. Other asthma subjects were exposed to acid fog containing sulfate and ammonium ions. Again, pulmonary and bronchial function were not modified after inhalation.

  8. Acute exposure to realistic acid fog: effects on respiratory function and airway responsiveness in asthmatics.

    PubMed

    Leduc, D; Fally, S; De Vuyst, P; Wollast, R; Yernault, J C

    1995-11-01

    Naturally occurring fogs in industrialized cities are contaminated by acidic air pollutants. In Brussels, Belgium, the pH of polluted fogwater may be as low as 3 with osmolarity as low as 30 mOsm. In order to explore short-term respiratory effects of a realistic acid-polluted fog, we collected samples of acid fog in Brussels, Belgium, which is a densely populated and industrialized city, we defined characteristics of this fog and exposed asthmatic volunteers at rest through a face mask to fogs with physical and chemical characteristics similar to those of natural fogs assessed in this urban area. Fogwater was sampled using a screen collector where droplets are collected by inertial impaction and chemical content of fogwater was assessed by measurement of conductivity, pH, visible colorimetry, high pressure liquid chromatography, and atomic absorption spectrophotometry over a period of one year. The fogwater composition was dominated by NH4+ and SO4- ions. First we evaluated the possible effect of fog acidity alone. For this purpose 14 subjects with asthma were exposed at rest for 1 hr [mass median aerodynamic diameter to a large-particle (MMAD), 9 microns] aerosol with H2SO4 concentration of 500 micrograms/m3 (pH 2.5) and osmolarity of 300 mOsm. We did not observe significant change in pulmonary function or bronchial responsiveness to metacholine. In the second part of the work, 10 asthmatic subjects were exposed to acid fog (MMAD, 7 microns) containing sulfate and ammonium ions (major ions recovered in naturally occurring fogs) with pH 3.5 and osmolarity 30 mOsm. Again, pulmonary function and bronchial reactivity were not modified after inhalation of this fog. It was concluded that short-term exposure to acid fog reproducing acidity and hypoosmolarity of natural polluted fogs does not induce bronchoconstriction and does not change bronchial responsiveness in asthmatics.

  9. Effects of acid fog on airway function in people with asthma. Final report

    SciTech Connect

    Sheppard, D.; Balmes, J.R.; Christian, D.

    1988-11-30

    The study was built on earlier work examining the effects of acidic fog on human subjects with asthma. Mouthpiece exposure studies on asthmatic subjects showed that both nitric and sulfuric acids potentiate the bronchoconstrictor effects of fog water, and that these acids appear to be similar in this respect. The work resulted in the exposure chamber at the University of California, San Francisco being extensively modified, based on improvements recommended in an earlier investigation, thus allowing human subjects to be exposed to rigorously controlled and monitored test fogs. The study used the chamber to first examine the effects of fog without acid, and then the effects of fog with acid, on exercising subjects with asthma.

  10. An assessment of acid fog

    SciTech Connect

    Lipfert, F.W.

    1992-12-31

    Airborne particles have long been associated with adverse effects on public health, begin with the notorious air pollution disasters of several decades ago. Although H{sub 2}SO{sub 4} was identified early on as a potential causal factors during these episodes (in part because of concern for potential health effects of particle acidity per se has intensified only recently. Most of the recent aerometric research in the US on acid fog has focused on the ability of clouds and fog to deliver acidity to vegetation and ecosystems. Strong acids are characterized chemically by their pH or H{sup +} concentration. For fog, concentrations are referred to the droplet liquid content; for other (i.e., ``clear air``) aerosols, to the volume of air sampled. A useful measure of the relationship between aerosol and fog is obtained by comparing their mass concentrations on the basis of the same volume of air, by multiplying fogwater concentrations by liquid water content (LWC). This paper reviews fog measurement capability, physical properties and chemistry, and presents a simple urban airshed model which is used to simulate the evolution of fog and aerosol concentrations under urban stagnation conditions.

  11. The effects of sequential exposure to acidic fog and ozone on pulmonary function in exercising subjects

    SciTech Connect

    Aris, R.; Christian, D.; Sheppard, D.; Balmes, J.R. )

    1991-01-01

    In Southern California coastal regions, morning fog is often acidified by the presence of nitric acid (HNO{sub 3}). Peak exposure to ozone (O{sub 3}) usually occurs in the afternoon and evening, after the fog has dissipated. To determine whether fog containing HNO{sub 3} might enhance pulmonary responses to O{sub 3}, we studied a group of healthy, athletic subjects selected for lung function sensitivity to O{sub 3}. On 3 separate days, the subjects exercised for 2 h in atmospheres containing HNO{sub 3} fog (0.5 mg/ml), H{sub 2}O fog, or clean, filtered air. After a 1-h break, they exercised for an additional 3 h in an atmosphere containing 0.20 ppm O{sub 3}. Surprisingly, the mean O{sub 3}-induced decrements in FEV1 and FVC were smaller after exercise in each fog-containing atmosphere than they were after exercise in clean, filtered air. The mean (+/- SEM) O{sub 3}-induced decrements in FEV1 were 26.4 +/- 5.3% after air, 17.1 +/- 3.7% after H{sub 2}O fog, and 18.0 +/- 4.3% after HNO{sub 3} fog, and in FVC they were 19.9 +/- 4.7% after air, 13.6 +/- 2.8% after H{sub 2}O fog, and 13.6 +/- 4.2% after HNO{sub 3} fog.

  12. Acute exposure to acid fog: influence of breathing pattern on effective dose.

    PubMed

    Bowes, S M; Francis, M; Laube, B L; Frank, R

    1995-02-01

    Concern about the possible adverse health effects of acid fog has been fed by two observations: air pollution disasters earlier in this century were typically associated with fog, and current samples of fog water can be strongly acid. To study the acute effects of acid fog on the lung, the authors generated a monodisperse 10 microM MMAD aerosol of H2SO4 with a pH of 2.0 and a nominal concentration of 500 micrograms/m3. They exposed seven healthy young men on alternate days to acid or control equiosmolar NaCl aerosol during 40 min of resting ventilation and 20 min of exercise; the latter was sufficiently intense to induce oronasal breathing. Exposure was by means of a head dome, a head-only exposure device that permitted continuous measurement (unfettered breathing) of Vr, f, VE, and the onset and persistence of oronasal breathing. In this article the authors compare the relative importance of parameters contributing to the between-subject variability in estimated hydrogen ion dose to the lower airways (H+LAW), based on analysis of variance. Physiologic parameters accounted for 70% of the variability, of which 34% was due to differences in duration of oronasal breathing (tON) and 36% to differences in ventilation rate during oronasal breathing (VE(ON)); inhaled hydrogen ion concentration [H+], the environmental parameter, contributed only 30%. Minute ventilation at the time of transition from nasal to oronasal breathing varied significantly among subjects even if normalized to FVC, an index of lung size.

  13. Potential bronchoconstrictor stimuli in acid fog.

    PubMed

    Balmes, J R; Fine, J M; Gordon, T; Sheppard, D

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and niric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  14. Potential bronchoconstrictor stimuli in acid fog

    SciTech Connect

    Balmes, J.R.; Fine, J.M.; Gordon, T.; Sheppard, D.

    1989-02-01

    Acid fog is complex and contains multiple stimuli that may be capable of inducing bronchoconstriction. These stimuli include sulfuric and nitric acids, the principal inorganic acids present; sulfites, formed in the atmosphere as a reaction product of sulfur dioxide and water droplets; fog water itself, a hypoosmolar aerosol; the organic acid hydroxymethanesulfonate, the bisulfite adduct of formaldehyde; and gaseous pollutants, e.g., sulfur dioxide, oxides of nitrogen, ozone. Given this complexity, evaluation of the respiratory health effects of naturally occurring acid fog requires assessment of the bronchoconstrictor potency of each component stimulus and possible interactions among these stimuli. We summarize the results of three studies that involve characterization of the bronchoconstrictor potency of acid fog stimuli and/or their interaction in subjects with asthma. The results of the first study indicate that titratable acidity appears to be a more important stimulus to bronchoconstriction than is pH. The results of the second study demonstrate that sulfite species are capable of inducing bronchoconstriction, especially when inhaled at acid pH. The results of the third study suggest that acidity can potentiate hypoosmolar fog-induced bronchoconstriction.

  15. Acidic fog and temperature effects on stigmatic receptivity in two birch species

    SciTech Connect

    Hughes, R.N.; Cox, R.M.

    1994-07-01

    Factorial assays were performed to determine the effects of simulated acid fog (SAF) and temperature on stigmatic receptivity in two birch species. Excised reproductive branches were sampled from representative individuals of mountain paper birch (Betula cordifolia Regel.) and paper birch (Betula papyrifera Marsh.) in populations adjacent to the Bay of Fundy, New Brunswick, Canada. Since 1979 these trees have exhibited branch dieback in association with abnormal foliar browning symptoms. This browning has been linked with acidity and nitrate deposited by fog, which is frequent in the area. In general, experimental results indicated that pollen germination increased with temperature, but pH effects were less obvious. Similarly, pollen tube growth responded positively to temperature and was little affected by fog acidity. ANOVA tests indicated a significant difference (P < 0.05) between species in their pollen germination response only at 12{degrees}C, and not at the other three temperatures tested. For pollen tube growth, significant differences between species (P < 0.05) were demonstrated at 12 and 22{degrees}C. A significant pH effect was demonstrated at 27{degrees}C for germination, while pH effects on tube growth were significant at 27 and 12{degrees}C (P < 0.01). A response surface regression analysis indicated that acidity significantly affected pollen germination in mountain paper birch (P < 0.001) but not in paper birch. Temperature was not a significant factor for in vivo pollen germination in either species. For pollen tube growth, however, temperature was more important than pH and produced highly significant effects in both species (P < 0.001). Acidity was also a significant factor in pollen tube growth for paper birch. 39 refs., 4 figs., 3 tabs.

  16. Short-term respiratory effects of sulfuric acid in fog: a laboratory study of healthy and asthmatic volunteers

    SciTech Connect

    Avol, E.L.; Linn, W.S.; Wightman, L.H.; Whynot, J.D.; Anderson, K.R.; Hackney, J.D.

    1988-03-01

    To explore short-term respiratory health risks from acid-polluted fog, 22 normal and 22 asthmatic adult volunteers were exposed in an environmental control chamber to light fogs containing nominally 0, 500, 1000, and 2000 ..mu..g/m/sup 3/ of sulfuric acid. Fog was produced by atomizing dilute acid solution into purified air humidified to near 100% by stem injection. Exposures were administered in random order at 1-week intervals, lasted 1 h, and included three 10-min periods of moderately heavy exercise. Responses were measured in terms of forced expiratory function, airway resistance, irritant symptoms, and bronchial reactivity to methacholine aerosol. Sulfuric acid per se showed no more than a slight effect on pulmonary function, even at the highest concentration. Asthmatics experienced bronchoconstriction, attributable to exercise, under all exposure conditions. Despite the lack of substantial function changes, modest statistically significant increases in respiratory symptoms occurred with increasing acid concentrations. This unusual response pattern suggests that acid fog effects occur via a mechanism somewhat different from those which govern responses to irritant gases like SO/sub 2/ or O/sub 3/. To the extent these results are relevant to ambient acid fog exposures, they predict that no pulmonary dysfunction, and only slight respiratory symptoms if any, are likely to occur.

  17. Acid fog: effects on respiratory function and symptoms in healthy and asthmatic volunteers

    SciTech Connect

    Hackney, J.D.; Linn, W.S.; Avol, E.L.

    1989-02-01

    Acidic air pollutants generally are dissolved in water droplets. Mean droplet diameter may range from more than 10 microns in dense fog to less than 1 micron at low relative humidity. Droplet size influences the deposition of inhaled acid within the respiratory tract and thus may influence toxicity. To help assess health risks from acid pollution, we performed controlled exposures of normal and asthmatic volunteers to sulfuric acid aerosols at nominal concentrations of 0 (control), 500, 1000, and 2000 micrograms/m/sup 3/. Exposures lasted 1 hr with intermittent heavy exercise. Response was assessed by lung function tests and symptom questionnaires. Under foggy conditions (mean droplet size 10 microns, temperature 50 degrees F), no marked effects on lung function were found. However, both normal and asthmatic subjects showed statistically significant dose-related increases in respiratory symptoms. In a separate study, normal subjects exposed at 70 degrees F with mean droplet size 0.9 microns showed no marked effect on function or symptoms. Asthmatics showed dose-related decrements in forced expiratory performance and increases in symptoms, most obvious at 1000 and 2000 micrograms/m/sup 3/. The different results of the two studies probably reflect an influence of droplet size, but further investigation is needed to confirm this. The aggregate results suggest that only mild, if any, short-term respiratory irritant effects are likely at acid concentrations attained in ambient pollution.

  18. Acid fog: effects on respiratory function and symptoms in healthy and asthmatic volunteers.

    PubMed

    Hackney, J D; Linn, W S; Avol, E L

    1989-02-01

    Acidic air pollutants generally are dissolved in water droplets. Mean droplet diameter may range from more than 10 microns in dense fog to less than 1 micron at low relative humidity. Droplet size influences the deposition of inhaled acid within the respiratory tract and thus may influence toxicity. To help assess health risks from acid pollution, we performed controlled exposures of normal and asthmatic volunteers to sulfuric acid aerosols at nominal concentrations of 0 (control), 500, 1000, and 2000 micrograms/m3. Exposures lasted 1 hr with intermittent heavy exercise. Response was assessed by lung function tests and symptom questionnaires. Under foggy conditions (mean droplet size 10 microns, temperature 50 degrees F), no marked effects on lung function were found. However, both normal and asthmatic subjects showed statistically significant dose-related increases in respiratory symptoms. In a separate study, normal subjects exposed at 70 degrees F with mean droplet size 0.9 microns showed no marked effect on function or symptoms. Asthmatics showed dose-related decrements in forced expiratory performance and increases in symptoms, most obvious at 1000 and 2000 micrograms/m3. The different results of the two studies probably reflect an influence of droplet size, but further investigation is needed to confirm this. The aggregate results suggest that only mild, if any, short-term respiratory irritant effects are likely at acid concentrations attained in ambient pollution.

  19. Effects of naturally-occurring acid fog on inflammatory mediators in airway and pulmonary functions in asthmatic patients.

    PubMed

    Honma, S; Tanaka, H; Teramoto, S; Igarashi, T; Abe, S

    2000-10-01

    Floating fog occurs every summer in Kushiro City in Japan, and the annual average of fog water pH in the past 4 years has been under 5.0. We previously reported that epidemiologically fog was the most important positive factor contributing to increased hospital visits of asthmatic patients compared with other meteorological values and air pollutants. This study aimed to investigate the mechanism of the effects of naturally-occurring acid fog on asthmatic patients. We compared pulmonary functions and inflammatory mediators in induced sputum between the foggy (July 1995) and the non-foggy (May 1996) season, and assessed airway responsiveness to hypo-osmolar aerosol. Forty-four out of 118 asthmatic patients of Kushiro City residents participated, pulmonary function tests were completed in 36 patients, and sputum data were available in 26 patients in both seasons. Percent forced expiratory volume in 1 sec (FEV1) was significantly (P< 0.05) decreased, and % peak expiratory flow rate (PEFR) had a trend to decrease in the foggy season more than in the non-foggy, and sputum eosinophil cationic protein (ECP) and interleukin (IL)-8 were higher in the foggy season but not significantly. A moderate inverse correlation was revealed between sputum ECP and %PEFR in the foggy season (r= -0.55, P<0.005). Subjects were divided into two groups according to the best PEFR; one had >10% lower PEFR levels in the foggy season than in the non-foggy season (Group A, n = 7), the remainder did not (Group B, n = 19). In group A, sputum ECP was significantly increased (P< 0.01) in the foggy season, but there were no changes in IL-8 and prostaglandin D2. Ultrasonic nebulized distilled water provocation test revealed no differences between group A and B. These results suggested that eosinophilic inflammation rather than hypo-osmolar effect of fog might contribute to respiratory deterioration by inhalation of naturally-occurring acid fog.

  20. Foliar leaching and root uptake of Ca, Mg and K in relation to acid fog effects on Douglas Fir

    SciTech Connect

    Turner, D.P.; Tingey, D.T.

    1990-01-01

    The impact of acid fog on foliar leaching and root uptake of Ca, Mg, and K by Douglas-fir (Pseudotsuga menziesii) seedlings was examined. In a factorial experiment, 1-year old seedlings were grown in a solution culture at two levels of nutrient availability (low and moderate) and exposed twice a week (4 hr per event) for 12 weeks to fog at pH 5.6 or pH 3.1. Throughfall enrichment of Ca, Mg and K was determined from drip collectors at the base of each seedling and root uptake rates for trees under the moderate nutrient regime were evaluated by monitoring nutrient solution depletion. Throughfall enrichment was higher in the pH 3.1 fog than the pH 5.6 fog but much of the enrichment appeared to be wash off of precipitate from previous fogs. The amounts of nutrients coming off of the foliage with the low pH fog were small relative to the daily uptake rates. Foliar concentrations of K and Mg at the end of the exposures were lower under the low nutrient regime but were not affected by fog pH. Comparisons of wax weight and examinations of epicuticular wax by electron microscopy did not indicate a significant impact from exposure to the low pH fog.

  1. Effects of prolonged, sequential exposure to acid fog and ozone on pulmonary function in exercising, normal subjects. Final report, 28 Feb 89-28 Dec 90

    SciTech Connect

    Balmes, J.

    1990-05-01

    Thirty-nine apparently healthy and asymptomatic subjects were selected for a study that screened for sensitivity to ozone. After three hours of ozone exposure (at 0.20 ppm), eighteen of the subjects (46 percent) experienced a 10 percent reduction in forced expiratory volume, an indicator of exhaling ability. After four hours of exposure, 62 percent of the subjects experienced a similar reduction in expiratory volume. Further, narrowing of airways among the sensitive subjects was suggested by results of the methacholine challenge test, a standard test for measuring airway resistance. The lung capacity of all subjects decreased progressively during ozone exposures. Capacity was unchanged during acidic fog and pollutant-free air exposures. No statistically significant differences in airway resistance, airway responsiveness and symptoms that could be attributed to acid fog exposure were observed. The study indicates that exposue to fog containing nitric acid followed by exposure to ozone does not have additive or synergistic acute effects. However, the study confirms earlier indications that many apparently healthy and asymptomatic individuals are susceptible to and adversely affected by ozone at relatively low concentrations.

  2. California's fog is far more polluted than acid rain

    SciTech Connect

    Roberts, L.

    1982-11-01

    In the Los Angeles area, measurements reveal that the fog has a pH between 2.5 and 3. Near congested areas, the fog is consistenly acidic and is laden with sulfate, nitrate, ammonium ion, lead, copper, nickel, vanadium and aldehydes. Acid fog formation involves a conversion of SO/sub 2/ and NO/sub x/ to sulfuric and nitric acids. Unlike acid rain, acid fog remains suspended in the air for hours and is a threat to human health as well as vegetation and materials. Fog forms close to the ground where concentrations of pollutants are higher than they are further aloft. Acid fog seems to be related to ground-based pollution sources, particularly power plant and automobile emissions. Samples were collected in locations far from major pollution sources and used to test the composition and acidity of normal fog. The pH values ranged from 3, near Los Angeles, to 7, near Morro Bay. Mathematical models are used to explain changes in acidity over time and to indicate a cyclical pattern.

  3. Acid fog deposition and the declining forest in Tanzawa mountains, Japan.

    NASA Astrophysics Data System (ADS)

    Igawa, M.; Shigihara, A.; Goto, S.; Nanzai, B.

    2010-07-01

    Since 1988, we have investigated fog chemistry in Mt. Oyama, Tanzawa mountains, Japan, and acid fog has been frequently observed there. We have observed fog on Mt. Oyama by using a night view video camera placed at the base of the mountain, by using a visibility meter at the top of the mountain, and by an active fog sampler at the mountainside. We have reported the fog frequency at the top of Mt. Oyama to be 46% measured by the video camera, but it was overestimated. The visibility measured at the top of the mountain is the most reliable index, and the top of the mountain is covered with fog for about 30%. The frequency of about 15% was added for the case of the visibility of a few km when it was measured by a night view video camera placed at the base of the mountain (8.5 km far from the top). Fog-water deposition increases with the increasing altitude to be much larger than the rain-water deposition. The factors affecting on the occult precipitation intensity were investigated by the simultaneous measurement of the rainfall intensity under a canopy, the wind speed and direction, and the visibility at the top of the mountain. Air pollution has been improved recently in Japan, but acid fog is not improved and has been affecting the leaves of the trees. In Tanzawa mountains, many fir trees and beech trees are declining, while cedar trees show no decline symptoms. We have investigated the effect of acid fog on the trees of these species by exposing simulated acid fog on the seedlings of the species. Seedlings of fir and beech are much damaged by the long term exposure of pH 3 fog, while cedar seedlings are not affected by the acid fog. By the exposure of simulated acid fog, the epicuticle wax is eroded at first, then the cross linking polycation between sugar chains of cell wall is ion-exchanged with proton and the cell wall is swollen, and the membrane calcium is desorbed from the membrane, which lowers the tolerance of the trees to the climate change. Fir and beech

  4. Respiratory responses to laboratory-generation acid fog in healthy and asthmatic volunteers

    SciTech Connect

    Avol, E.L.; Linn, W.S.; Hackney, J.D. )

    1987-01-01

    The authors discuss a program to provide a first step towards assessing acute health-related effects of acid fog exposure. Polluted ambient fog was simulated in a laboratory exposure chamber. Volunteer subjects were purposely exposed and studied during periods of exercise and rest while in the challenge atmosphere. Respiratory responses were measured by methods used to assess effects of irritant gases and dry'' respirable aerosols. When a pilot study showed no obvious unfavorable effects with ambient-like pollution conditions, the exposure concentrations for the present study were extended into the occupational range, well above ambient levels. Sulfuric acid was selected for use as the test pollutant, based upon previous research experience and the availability of fog data documenting its presence during ambient fog episodes.

  5. Internal acid buffering in San Joaquin Valley fog drops and its influence on aerosol processing

    NASA Astrophysics Data System (ADS)

    Collett, Jeffrey L.; Hoag, Katherine J.; Rao, Xin; Pandis, Spyros N.

    Although several chemical pathways exist for S(IV) oxidation in fogs and clouds, many are self-limiting: as sulfuric acid is produced and the drop pH declines, the rates of these pathways also decline. Some of the acid that is produced can be buffered by uptake of gaseous ammonia. Additional internal buffering can result from protonation of weak and strong bases present in solution. Acid titrations of high pH fog samples (median pH=6.49) collected in California's San Joaquin Valley reveal the presence of considerable internal acid buffering. In samples collected at a rural location, the observed internal buffering could be nearly accounted for based on concentrations of ammonia and bicarbonate present in solution. In samples collected in the cities of Fresno and Bakersfield, however, significant additional, unexplained buffering was present over a pH range extending from approximately four to seven. The additional buffering was found to be associated with dissolved compounds in the fogwater. It could not be accounted for by measured concentrations of low molecular weight ( C1- C3) carboxylic acids, S(IV), phosphate, or nitrophenols. The amount of unexplained buffering in individual fog samples was found to correlate strongly with the sum of sample acetate and formate concentrations, suggesting that unmeasured organic species may be important contributors. Simulation of a Bakersfield fog episode with and without the additional, unexplained buffering revealed a significant impact on the fog chemistry. When the additional buffering was included, the simulated fog pH remained 0.3-0.7 pH units higher and the amount of sulfate present after the fog evaporated was increased by 50%. Including the additional buffering in the model simulation did not affect fogwater nitrate concentrations and was found to slightly decrease ammonium concentrations. The magnitude of the buffering effect on aqueous sulfate production is sensitive to the amount of ozone present to oxidize S

  6. Acid fog damage of beech at Hinokiboramaru-Tanzawa, Japan.

    PubMed

    Nara, C; Dokiya, Y; Usui, N; Maruta, E; Hua, L F; Sagi, T

    2001-01-01

    Decline of Japanese beech forest has been obvious at the Tanzawa Mountains near Tokyo. Observations on fog, precipitation and stem flow were performed during June-October, 1994 on both, NE (with healthy beech) and S-SE (with unhealthy beech) slopes, collecting samples biweekly. Chemical species were determined by ion-chromatography and pH meter. The results show that the pH of the precipitation was between 4.4-5.2, with no clear differences in the concentrations of chemical species between both sites and seasons. The pH of the fog water was high from May to the middle of August and lower from mid-August to October at both sites. The concentrations of most chemical species were higher in fog samples than precipitation samples. The concentrations of potassium and magnesium ions in the stem flow of an unhealthy tree on the S-SE slope were higher than those on the NE slope. In June-October, 1995, ten pairs of event fog water samples were obtained with indicating that the pH was below 4.0 for five pairs of event fog water samples. Lower pH value was obtained on the S-SE slope than on the NE slope in every event. Concentrations of most chemical species were always higher in the fog samples from the S-SE slope than those from the NE slope. The equivalent ratio of NO3-/nssSO4(2-) was higher in the fogs of higher acidity. From the result of atmospheric current analysis using a model, it was suggested that the polluted air over the Tokyo Metropolitan Area affected the fog acidity directly and also indirectly, according to the pressure patterns.

  7. Mathematical modeling of acid deposition due to radiation fog

    SciTech Connect

    Pandis, S.N.; Seinfeld, J.H. )

    1989-09-20

    A Lagrangian model has been developed to study acidic deposition due to radiation fog. The model couples submodels describing the development and dissipation of radiation fog, the gas-phase chemistry and transfer, and the aqueous-phase chemistry. The model is applied to a radiation fog episode in Bakersfield in the San Joaquin Valley of California over the period January 4--5 1985. Model predictions for temperature profile, fog development, liquid water content, gas-phase concentrations of SO{sub 2}, HNO{sub 3}, and NH{sub 3}, {ital p}H, aqueous-phase concentrations of OS{sup 2{minus}}{sub 4}, NH{sup +}{sub 4}, and NO{sup {minus}}{sub 3}, and finally deposition rates of the above ions are compared with the observed values. The deposition rates of the major ions are predicted to increase significantly during the fog episode, the most notable being the increase of sulfate deposition. Pathways for sulfate production that are of secondary importance in a cloud environment may become signficant in a fog. Expressing the mean droplet settling velocity as a function of liquid water content is found to be quite influential in the model's predictions. {copyright} American Geophysical Union 1989

  8. The effect of aerosol on radiation fog life-cycle

    NASA Astrophysics Data System (ADS)

    Romakkaniemi, Sami; Maalick, Zubair; Tonttila, Juha; Kuhn, Thomas; Kokkola, Harri

    2016-04-01

    Radiation fog is formed during the night under clear skies when emission of long wave radiation cools the surface and air above it. After formation, the development of fog is further influenced by longwave cooling and turbulence entrainment-detrainment at the top of the fog layer, and microphysical processes through droplet activation and sedimentation. After sunrise, the fog is dissipated due heating of the surface and the air above it. Like in the case of clouds, atmospheric aerosol particles also affect the properties of fog and together with meteorological conditions determine their life cycle from formation to dissipation. To explore how aerosols are affecting radiation fog properties and lifetime, we have used a Large Eddy Model with explicit representation of aerosol particles and aerosol-fog droplet interactions. Our results show that the fog droplet concentration increases with increasing aerosol concentration. In the early stages of fog formation the radiative cooling at the top of the fog controls the maximum water supersaturation and droplet formation in a similar manner than the updraft velocity does at the base of a cloud. The liquid water content in the fog is mainly determined by the droplet concentration as large droplets are efficiently removed through sedimentation. Thus, with increasing aerosol particle concentration, the more numerous, but smaller fog droplets increase the fog's optical depth and thereby delay the fog dissipation after sunrise, because the surface warms more slowly. This effect is further enhanced if turbulence inside the fog leads to secondary activation of droplets. Overall, the radiation fog dissipation in polluted conditions can be delayed up to hours when compared to clean conditions.

  9. Exposure of two upland plant species to acidic fogs.

    PubMed

    Ashenden, T W; Rafarel, C R; Bell, S A

    1991-01-01

    A system is described for exposing large numbers of plants to acidic fogs. The system allows low volumes of treatment solutions to be provided at particle sizes chiefly in the 5-30 microm range (equivalent to fog/cloud droplets). Plants of Poa alpina L. and Epilobium brunnescens were propagated from material collected in Snowdonia, North Wales and exposed to fog treatments at pH values of 2.5, 3.5, 4.5 and 5.6. There were 3 x 4 h exposures per week which provided a total of 6 mm deposition. Supplementary watering was with pH 4.5 simulated acid rain (24 mm per week). After 21 weeks, there was increased lowering and a greater dry weight for plants of E. brunnescens exposed to the pH 2.5 fog in comparison with other treatments. Also, the plants used assimilated material to form shoots rather than roots. A similar increase in dry weight accumulation in the pH 2.5 treatment was found in P. alpina after 63 weeks but this was not associated with changes in assimilate partitioning.

  10. [Acid fog: hygiene and health observations correlated with an aspect of atmospheric pollution].

    PubMed

    Gilli, G; Bono, R; Scursatone, E; Carraro, E

    1989-01-01

    In the last years the interest about acid depositions has been shifted to heterogeneous phase reactions and, particularly, to occult precipitations (fog, mist, ecc.). It is very improbable that some kind of human health hazards could derive from acid rain exposure. Instead, the human exposure to acid fog could represent a possible respiratory vehicle for the assumption of acid pollutants as well as of many other pollutants. This last assertion can be supported by the following considerations: 1) Fog may represent an important chemical reactor that can modify the nature of pollutant material in the atmosphere (acidification and other events). 2) Fog is formed near the ground where pollution sources are located so that pollution is the heaviest. The fog water droplets coalesce around preexisting aerosol which is most highly concentrated near the ground (cities and industrial areas). Since fog water droplets contain muc less water than rain drops, they do not dilute the acidity as much as rain. 3) Finally, fog is partially inhalable. In certain areas of the world, wet deposition by fog can be important to the human health, even if the acqueous concentrations of fog droplets, the acidity per volume of air and the acid deposition rate are all important factors to consider. Particularly the pH of fog does not tell the whole story, but it represents a sufficient information about the severity of the atmospheric situation that can be correlated to seriousness of human risk.

  11. Discrimination of ionic pollutants except condensation nuclei of acid fog using an ultrasonic humidifier.

    PubMed

    Yoshimura, Keiji; Kikuchi, Ryoei; Kimoto, Takashi; Ozeki, Toru; Imano, Kazuhiko; Kajikawa, Masahiro; Ogawa, Nobuaki

    2006-06-01

    Fog droplets in the atmosphere are first produced by the activation of cloud condensation nuclei (CCN), which are originally some ionic compound. Subsequently, the nuclei grow by vapor diffusion. Fog droplets are polluted through the activation process and successive diffusion growth and residence (post activation). We cannot distinguish the effects of the two pollution processes of natural fog water samples. We found that fog droplets can be produced artificially without CCN using an ultrasonic humidifier. Because the artificial fog droplets are not polluted by CCN, the movement of the fog droplets in natural air will take up some pollutants in the air. Consequently, the two pollution processes of fog (the activation of CCN and the post activation process) can be discriminated using data from field experiments. This sampling analytical method is extremely important for further research regarding fog, clouds and environmental chemistry. PMID:16772683

  12. Discrimination of ionic pollutants except condensation nuclei of acid fog using an ultrasonic humidifier.

    PubMed

    Yoshimura, Keiji; Kikuchi, Ryoei; Kimoto, Takashi; Ozeki, Toru; Imano, Kazuhiko; Kajikawa, Masahiro; Ogawa, Nobuaki

    2006-06-01

    Fog droplets in the atmosphere are first produced by the activation of cloud condensation nuclei (CCN), which are originally some ionic compound. Subsequently, the nuclei grow by vapor diffusion. Fog droplets are polluted through the activation process and successive diffusion growth and residence (post activation). We cannot distinguish the effects of the two pollution processes of natural fog water samples. We found that fog droplets can be produced artificially without CCN using an ultrasonic humidifier. Because the artificial fog droplets are not polluted by CCN, the movement of the fog droplets in natural air will take up some pollutants in the air. Consequently, the two pollution processes of fog (the activation of CCN and the post activation process) can be discriminated using data from field experiments. This sampling analytical method is extremely important for further research regarding fog, clouds and environmental chemistry.

  13. Urbanization Effects on Fog in China: Field Research and Modeling

    NASA Astrophysics Data System (ADS)

    Li, Zi-hua; Yang, Jun; Shi, Chun-e.; Pu, Mei-juan

    2012-05-01

    Since the policy of "Reform and Open to the Outside World" was implemented from 1978, urbanization has been rapid in China, leading to the expansion of urban areas and population synchronous with swift advances in economy. With urban development underway, the urban heat island (UHI) and air pollution are being enhanced, together with vegetation coverage and relative humidity on the decrease. These changes lead to: (1) decline of annual fog days in cities (e.g. In Chongqing, so-called city of fog in China, the annual fog days have reduced from 100-145 in the 1950s to about 20-30 in the 2000s); (2) decrease in fog water content (FWC) and fog droplet size, but increase in fog droplets number concentration [e.g. Jinghong, a city in Yunnan province, the average FWC (the droplet diameter) during an extremely dense fog episode with drizzle was 0.74 g/m3 (28.6 μm) during the 1968/69 winter and 0.08 g/m3 (6.8 μm) in another extremely dense fog episode during the 1986/87 winter, correspondingly, the fog droplets number density had increased from 34.9 to 153 cm-3]; (3) decrease in fog water deposition (FWD) (e.g. the annual mean FWD measured in Jinghong had dropped from 17.3 mm in the 1950s to 4.4 mm in the 1970s and less than 1 mm in the 1980s, and no measurable FWD now.); (4) decrease in visibility in large cities (e.g. in Chongqing, the annual average visibility had decreased from 8.2-11.8 km in the 1960s to 4.9-6.5 km in the 1980s, and around 5 km in recent years); and (5) increase in the ion concentrations and acidity in fog water in urban areas [e.g. the average total ion concentration (TIC) in the center of Chongqing was 5.5 × 104 μmol/L, with mean pH value of 4.0, while the corresponding values are 9.7 × 103 μmol/L and over 5.5 in its rural area]. These changes endanger all kinds of transportation and human health. This paper summarized the authors' related studies, including observations and numerical simulations to confirm the above conclusions.

  14. Uptake and distribution of nitrogen from acidic fog within a ponderosa pine (Pinus ponderosa Laws.)/litter/soil system

    SciTech Connect

    Fenn, M.E.; Leininger, T.D.

    1995-11-01

    The magnitude and importance of wet deposition of N in forests of the South Coast (Los Angeles) Air Basin have not been well characterized. We exposed 3-yr-old ponderosa pine (Pinus ponderosa Laws.) seedlings growing in native forest soil to acidic fog treatments (pH 3.1) simulating fog chemistry from a pine forest near Los Angeles, California. Fog solutions contained either {sup 15}NH{sub 4}{sup +}, {sup 15}NO{sub 3}{sup {minus}}, or unlabeled N. The fog treatments were applied in open-top chambers in six 5-hr exposures. Soil treatments within each of the fog exposures were bare soil, soil overlain with L- and F-litter, and soil covered with plastic during the fog events to prevent fogwater from contacting soil. Seedlings were harvested and samples were collected 15 wk after the fog treatments. Uptake of {sup 15}N by roots was by far the dominant pathway for plant assimilation of fog-deposited {sup 15}N. Deposition of N in fog supplied 9.4% and 8.7% of the total N in current-year crown biomass in the litter-overlay and bare-soil treatments, respectively. Total N concentrations in every plant fraction except current-year stems were significantly higher in the bare-soil treatment than in the plastic-covered soil treatment. Less than 5% of the {sup 15}N deposited directly to the seedling crowns was retained by the plants in the covered-soil treatment, whereas 57% of the {sup 15}N deposited to the seedling/litter/soil systems was incorporated into plant biomass. The litter layers retained {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NH{sub 4}{sup +} more effectively than {sup 15}NO{sub 3}. Data from this study suggest that N deposited from fog may be an important source of N for plant growth in forests of the SCAB where fog occurrence and pollution exposure coincide. 5 refs., 5 figs., 3 tabs.

  15. Effects of Chinese Urban Development on the Fog

    NASA Astrophysics Data System (ADS)

    Li, Z. H.; Yang, J.; Shi, C. E.; Pu, M. J.; Liu, D. Y.

    2010-07-01

    Since China adopted the reform and opening-up policy in late 1978, the national economy as well as urbanization have developed rapidly, causing urban growth and population growth. In consequence, the urban heat islands strengthen and air pollution increase but the vegetation cover decreases, leading to the relative humidity decreases. These changes led directly to the city's foggy day reduction, fog liquid water content (LWC) and droplet-scale decreases, droplet number concentration increases, visibility degradation sharply in fog, fog-ion concentration and acidity larger, which increase the traffic hazard and endanger human health seriously. In this paper, a large number of observations and numerical simulations have been done to demonstrate these conclusions. Suggestions that air pollution controlling, virescence and improving the urban ecological environment was given at the end of the particle.

  16. Severe leaching of calcium ions from fir needles caused by acid fog.

    PubMed

    Igawa, Manabu; Kase, Toshiyuki; Satake, Kosuke; Okochi, Hiroshi

    2002-01-01

    We have measured the components of the throughfall under fir trees (Abies firma) in the field around Mt. Oyama, where the forest appears to be declining, for the period 1994-1998. Exposure experiments of a simulated acid fog to fir twigs were performed under field conditions. There was a similarity between the acid response in the field and that in the laboratory. In both studies, the severe leaching of calcium ions from the needle surface was caused by exposure to acid fog. We also applied acid fog to fir seedlings over 1 year and observed a decrease in the growth of the seedlings due to this application in the dormant season. These results suggest that the severe leaching of calcium ions due to acid fog may cause the deficiency of calcium and be responsible for the decline of the fir trees.

  17. Evaluation of ionic pollutants of acid fog and rain using a factor analysis and back trajectories.

    PubMed

    Adzuhata, T; Inotsume, J; Okamura, T; Kikuchi, R; Ozeki, T; Kajikawa, M; Ogawa, N

    2001-01-01

    Fog and rain water samples were collected at the same time in the Akita Hachimantai mountain range in northern Japan from June to September in 1998 and 1999. The various ion concentrations in these samples were analyzed, and the fog droplet sizes were measured for each fog event. As the fog droplet size increased, the ion concentration decreased. The slope of log-log plots of the concentration versus the droplet size differed with the kind of ion. In order to characterize the air pollutant, moreover, these data were quantitatively analyzed by an oblique rotational factor analysis. We found that three factors were extracted as the air pollutant source: (NH4)2SO4, acids (HNO3 + H2SO4) and sea-salt. Combining the factor analysis with the 72 h back-trajectory at 850 hPa level, we found that the contribution of each factor varied with the transport pattern of air masses.

  18. Evaluation of ionic pollutants of acid fog and rain using a factor analysis and back trajectories.

    PubMed

    Adzuhata, T; Inotsume, J; Okamura, T; Kikuchi, R; Ozeki, T; Kajikawa, M; Ogawa, N

    2001-01-01

    Fog and rain water samples were collected at the same time in the Akita Hachimantai mountain range in northern Japan from June to September in 1998 and 1999. The various ion concentrations in these samples were analyzed, and the fog droplet sizes were measured for each fog event. As the fog droplet size increased, the ion concentration decreased. The slope of log-log plots of the concentration versus the droplet size differed with the kind of ion. In order to characterize the air pollutant, moreover, these data were quantitatively analyzed by an oblique rotational factor analysis. We found that three factors were extracted as the air pollutant source: (NH4)2SO4, acids (HNO3 + H2SO4) and sea-salt. Combining the factor analysis with the 72 h back-trajectory at 850 hPa level, we found that the contribution of each factor varied with the transport pattern of air masses. PMID:11993680

  19. Effect of aerosol concentration and absorbing aerosol on the radiation fog life cycle

    NASA Astrophysics Data System (ADS)

    Maalick, Z.; Kühn, T.; Korhonen, H.; Kokkola, H.; Laaksonen, A.; Romakkaniemi, S.

    2016-05-01

    Analogous to cloud formation, the formation and life cycle of fogs is largely influenced by aerosol particles. The objective of this work is to analyze how changes in aerosol properties affect the fog life cycle, with special emphasis on how droplet concentrations change with cloud condensation nuclei (CCN) concentrations and on the effect that absorbing black carbon (BC) particles have on fog dissipation. For our simulation case study, we chose a typical fall time radiation fog at mid-latitudes (45° north) in fairly highly polluted conditions. Our results show that CCN concentrations have a strong influence on the fog lifetime. This is because the immediate effect of CCN on cloud droplet number concentrations (CDNC) is enhanced through two positive feedback loops: (1) Higher CDNC leads to more radiative cooling at the fog top, which leads to even stronger activation and (2) if CDNC is higher, the average droplet size is smaller, which slows down droplet removal through sedimentation. The effect that radiation fogs have on solar surface irradiation is large - the daily mean can change by 50% if CCN concentrations are doubled or halved (considering a reference CCN mixing ratio of 800 #/mg). With the same changes in CCN, the total fog lifetime increases 160 min or decreases 65 min, respectively. Although BC has a noticeable effect on fog height and dissipation time, its relative effect compared to CCN is small, even if BC concentrations are high. The fog formation is very sensitive to initial meteorological conditions which may be altered considerably if fog was present the previous day. This effect was neglected here, and future simulations, which span several days, may thus be a valuable extension of this study.

  20. Pesticides in fog.

    PubMed

    Glotfelty, D E; Seiber, J N; Liljedahl, L A

    The discovery of the very acidic nature of fog and clouds has created much interest in sampling, analysing, and elucidating the chemistry of fog, principally because an understanding of the chemical transformations leading to acid fog may provide important clues to the origin of acid rain. Recently, the knowledge of the chemistry of fog has expanded to include carbonyl compounds, volatile organic acids, and alkyl sulphonates. We have discovered that a variety of pesticides and their toxic alteration products are present in fog, and that they occasionally reach high concentrations relative to reported rainwater concentrations. In our experiments, we were able to measure the air-water distribution coefficients of pesticides between the liquid fog and the interstitial gas phase. These measurements reveal that some chemicals are enriched several thousandfold in the suspended liquid fog droplets compared to equilibrium distributions expected from Henry's Law coefficients for pure aqueous solutions.

  1. High frequency and large deposition of acid fog on high elevation forest.

    PubMed

    Igawa, Manabu; Matsumura, Ko; Okochi, Hiroshi

    2002-01-01

    We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites.

  2. Fog dispersion

    NASA Technical Reports Server (NTRS)

    Frost, W.; Christensen, L. S.; Collins, F. G.; Camp, D. W.

    1980-01-01

    A study of economically viable techniques for dispersing warm fog at commercial airports is presented. Five fog dispersion techniques are examined: evaporation suppression, downwash, mixing, seeding with hygroscopic material, thermal techniques, and charged particle techniques. Thermal techniques, although effective, were found to be too expensive for routine airport operations, and detrimental to the environment. Seeding or helicopter downwash are practical for small-scale or temporary fog clearing, but are probably not useful for airport operations on a routine basis. Considerable disagreement exists on the capability of charged particle techniques, which stems from the fact that different assumptions and parameter values are used in the analytical models. Recommendations resulting from the review of this technique are listed, and include: experimental measurements of the parameters in question; a study to ascertain possible safety hazards, such as increased electrical activity or fuel ignition during refueling operations which could render charged particle techniques impractical; and a study of a single charged particle generator.

  3. [Effect of fog on diurnal changes in peak expiratory flow rates in an asthmatic].

    PubMed

    Tanaka, H; Honma, S; Imada, A; Sugaya, F; Nishi, M; Abe, S

    1995-02-01

    To evaluate the effects of fog on asthmatics, we analyzed the symptoms of a 45-year-old female during the foggy season and the relation between diurnal peak expiratory flow rate (PEFR) and fog and other meteorological factors. Her asthma attacks had been induced by specific smells: perfume, smoke from burning grass or industrial smoke. Two years previously, she had moved to the suburbs of Sapporo, where fog frequently occurs. From that time her asthmatic symptoms had been exacerbated, so it was suspected that the fog might have had some influence. We analyzed 251 measures of PEFR from June to August 1994. The average and standard deviation of PEFR in the absence of fog and specific smells was 403 +/- 40 L/min (n = 195). PEFR was significantly lower (p < 0.01) when it was foggy (347 +/- 60 L/min; n = 40), when specific smells were present (333 +/- 60 L/min; n = 5) and when there were both fog and specific smells (340 +/- 53 L/min: n = 11). On the other hand, there were no changes associated with other meteorological factors: barometric pressures, relative humidity, mean temperature, minimal temperature and most frequent wind direction. These results suggested that the inhalation of fog decreases PEFR and is an exacerbating factor in bronchial asthma.

  4. [Effect of fog on diurnal changes in peak expiratory flow rates in an asthmatic].

    PubMed

    Tanaka, H; Honma, S; Imada, A; Sugaya, F; Nishi, M; Abe, S

    1995-02-01

    To evaluate the effects of fog on asthmatics, we analyzed the symptoms of a 45-year-old female during the foggy season and the relation between diurnal peak expiratory flow rate (PEFR) and fog and other meteorological factors. Her asthma attacks had been induced by specific smells: perfume, smoke from burning grass or industrial smoke. Two years previously, she had moved to the suburbs of Sapporo, where fog frequently occurs. From that time her asthmatic symptoms had been exacerbated, so it was suspected that the fog might have had some influence. We analyzed 251 measures of PEFR from June to August 1994. The average and standard deviation of PEFR in the absence of fog and specific smells was 403 +/- 40 L/min (n = 195). PEFR was significantly lower (p < 0.01) when it was foggy (347 +/- 60 L/min; n = 40), when specific smells were present (333 +/- 60 L/min; n = 5) and when there were both fog and specific smells (340 +/- 53 L/min: n = 11). On the other hand, there were no changes associated with other meteorological factors: barometric pressures, relative humidity, mean temperature, minimal temperature and most frequent wind direction. These results suggested that the inhalation of fog decreases PEFR and is an exacerbating factor in bronchial asthma. PMID:7726750

  5. Environmental effects of fog oil and CS usage at the Combat Maneuver Training Center, Hohenfels, Germany

    SciTech Connect

    Brubaker, K.L.; Rosenblatt, D.H.; Snyder, C.T.

    1992-03-01

    In response to environmental concerns at the Combat Maneuver Training Center (CMTC), Hohenfels, Germany, the US Army 7th Army Training Command commissioned a scientific study by Argonne National Laboratory to investigate specific issues. The study involved three parts: (1) a field study to determine if fog oil and CS (a compound named after its discoverers, B.B. Carson and R.W. Stoughton) were accumulating in the CMTC environment, (2) a screening of selected soil samples for the presence of US Environmental Protection Agency priority pollutants, and (3) a literature review of the health effects of fog oil and CS, as well as a review of training practices at CMTC. No fog oil or fog oil degradation products were detected in any soil, sediment, or vegetation sample collected at CMTC. Trace quantities of one or more priority pollutants were tentatively detected in three of eight soil and sediment samples. However, the priority pollutant concentrations are so low that they pose no environmental or health hazards. No evidence of widespread or significant contamination in the training areas was found. Crucial data needed to fully evaluate both acute and chronic health effects of civilian exposures to CS at CMTC are not available. On the basis of the available literature, long-ten-n health effects in the civilian population near CMTC that could result from the use of fog oil and CS during training activities are believed to be negligible.

  6. CHEMISTRY OF FOG WATER IN CALIFORNIA'S CENTRAL VALLEY: 2. PHOTOCHEMICAL TRANSFORMATIONS OF AMINO ACIDS AND ALKYL AMINES. (R825433)

    EPA Science Inventory

    Although amino compounds are seemingly ubiquitous in atmospheric particles and deposition, little is known of their fate in the troposphere. We report here on the fate of 21 amino acids and alkyl amines in fog waters from Davis, California, illuminated with simulated sunlight ...

  7. Fog inerting effects on hydrogen combustion in a PWR ice condenser contaminant

    SciTech Connect

    Luangdilok, W.; Bennett, R.B.

    1995-05-01

    A mechanistic fog inerting model has been developed to account for the effects of fog on the upward lean flammability limits of a combustible mixture based on the thermal theory of flame propagation. Benchmarking of this model with test data shows reasonably good agreement between the theory and the experiment. Applications of the model and available fog data to determine the upward lean flammability limits of the H{sub 2}-air-steam mixture in the ice condenser upper plenum region of a pressurized water reactor (PWR) ice condenser contaminant during postulated large loss of coolant accident (LOCA) conditions indicate that combustion may be suppressed beyond the downward flammability limit (8 percent H{sub 2} by volume). 18 refs., 3 tabs.

  8. Temperature and flow rate effects on mass median diameters of thermally generated malathion and naled fogs.

    PubMed

    Brown, J R; Chew, V; Melson, R O

    1993-06-01

    The effects of temperature and flow rate on mass median diameters (mmds) of thermally generated aerosol clouds were studied. Number 2 fuel oil alone, undiluted and diluted malathion 91, and undiluted naled were examined. There was a significant flow rate x temperature interaction on the mmds of diluted malathion fogs: i.e., differences among flow rates depended on temperature and vice versa.

  9. [Cool/Hot target effect of the water fog infrared stealth].

    PubMed

    Du, Yong-cheng; Yang, Li; Zhang, Shi-cheng; Yang, Zhen; Hu, Shuang-xi

    2012-08-01

    Artificial spray fog will come into being cool target because of the strong evaporation and convection but weak radiation heat flux, when it is used for defence of infrared imaging guided missile. Also, when it is the contrary condition, the water fog will come into being hot target. In order to open out the phenomenon particularly, a math model which can account for the cool/hot effect produced by water fog shielding the thermal radiation is established by coupling the calculation of radiation transfer equation and energy conversation equation, based on the Mie theory. This model is proved to be accurate in comparison with the Monte-Carlo method and Lambert-Beer' law. The water fog is seemed as absorbing, emitting and anisotropic scattering medium, and the medium radiation, multiple scattering, target radiation flux, and environment influence such as the conductivity, convection turbulent heat diffusion and evaporation is calculated. The phenomenon of cool/hot target effect can be shown in detail with this model. PMID:23156782

  10. Rain, fog, and clouds for aircraft simulators

    NASA Technical Reports Server (NTRS)

    Chase, W. D.

    1981-01-01

    Environmental chamber creates realistic fog and rain effects in aircraft simulator. It reproduces clouds, homogeneous fog, patches of fog, rain and fog, and rain only. It is used with real time digital computer, color computer generated image display that simulates airport lights, or color television camera that produces moving display of airport runway as depicted on model terrain board.

  11. Foliar uptake of fog water and transport belowground alleviates drought effects in the cloud forest tree species, Drimys brasiliensis (Winteraceae).

    PubMed

    Eller, Cleiton B; Lima, Aline L; Oliveira, Rafael S

    2013-07-01

    Foliar water uptake (FWU) is a common water acquisition mechanism for plants inhabiting temperate fog-affected ecosystems, but the prevalence and consequences of this process for the water and carbon balance of tropical cloud forest species are unknown. We performed a series of experiments under field and glasshouse conditions using a combination of methods (sap flow, fluorescent apoplastic tracers and stable isotopes) to trace fog water movement from foliage to belowground components of Drimys brasiliensis. In addition, we measured leaf water potential, leaf gas exchange, leaf water repellency and growth of plants under contrasting soil water availabilities and fog exposure in glasshouse experiments to evaluate FWU effects on the water and carbon balance of D. brasiliensis saplings. Fog water diffused directly through leaf cuticles and contributed up to 42% of total foliar water content. FWU caused reversals in sap flow in stems and roots of up to 26% of daily maximum transpiration. Fog water transported through the xylem reached belowground pools and enhanced leaf water potential, photosynthesis, stomatal conductance and growth relative to plants sheltered from fog. Foliar uptake of fog water is an important water acquisition mechanism that can mitigate the deleterious effects of soil water deficits for D. brasiliensis.

  12. Combined effects of organic aerosol loading and fog processing on organic aerosols oxidation and composition

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Tripathi, Sachchida; Gupta, Tarun

    2016-04-01

    Fog is a natural meteorological phenomenon that occurs throughout the world, it contains substantial quantity of liquid water and generally seen as a natural cleansing agent but it also has the potential to form highly oxidized secondary organic aerosols (SOA) via aqueous processing of ambient aerosols. On the other hand higher organic aerosols (OA) loading tend to decrease the overall oxidation level (O/C) of the particle phase organics, due to enhanced partitioning of less oxidized organics from gas to particle phase. However, combined impact of these two parameters; aqueous oxidation and OA loading, on the overall oxidation ratio (O/C) of ambient OA has never been studied. To assess this, real time ambient sampling using HR-ToF-AMS was carried out at Kanpur, India from 15 December 2014 - 10 February 2015. In first 3 weeks of this campaign, very high OA loading is (134 ± 42 μg/m3) observed (termed as high loading or HL period) while loading is substantially reduced from 2nd January, 2016 (56 ± 20 μg/m3, termed as low loading or LL period) . However, both the loading period was affected by several fog episodes (10 in HL and 7 in LL), thus providing the opportunity of studying the combined effects of fog and OA loading on OA oxidation. It is found that O/C ratio is very strongly anti-correlated with OA loading in both the loading period, however, slope of this ant-correlation is much steep during HL period than in LL period. Source apportionment of OA revealed that there is drastic change in the types of OA from HL to LL period, clearly indicating difference in OA composition from HL to LL period. During foggy night continuous oxidation of OA is observed from early evening to early morning with 15-20% enhancement in O/C ratio, while the same is absent during non-foggy period, clearly indicating the efficient fog processing of ambient OA. It is also found that night time fog aqueous oxidation can be as effective as daytime photo chemistry in oxidation of OA. Fog

  13. Microphysical characterization of free space optical link due to hydrometeor and fog effects.

    PubMed

    Mori, Saverio; Marzano, Frank S

    2015-08-01

    Free space optics (FSO) channel availability is affected by atmospheric water particles, which may introduce severe path attenuation. A unified microphysically oriented atmospheric particle scattering (MAPS) model is proposed and described to simulate particle scattering effects on FSO links. Atmospheric particles, such as raindrops, graupel particles, and snowflakes, together with fog droplets, are considered. Input data to characterize liquid and frozen water particle size distribution, density, and refractivity are derived from available literature data and measurements. Scattering, absorption, and extinction coefficients as well as the asymmetry factor are numerically simulated for each particle class and then parametrized with respect to particle water content, fall rate, and visibility, spanning from visible to infrared wavelengths. Both single- and multiple-scattering effects are discussed and quantified by using a radiative transfer model for small-angle approximation. MAPS simulations confirm that fog layers are those causing the largest power extinction on FSO links, but also several decibels of attenuation can be attributed to snow and rain conditions. Multiple-scattering effects, especially due to fog droplets, heavy rain, and dry snowflakes, typically tend to reduce the total attenuation by increasing the received power. An estimate of these effects, parameterized to single-scattering extinction, is proposed for near-infrared FSO link design.

  14. Temperature and flow rate effects on mass median diameters of thermally generated malathion and naled fogs.

    PubMed

    Brown, J R; Chew, V; Melson, R O

    1993-06-01

    The effects of temperature and flow rate on mass median diameters (mmds) of thermally generated aerosol clouds were studied. Number 2 fuel oil alone, undiluted and diluted malathion 91, and undiluted naled were examined. There was a significant flow rate x temperature interaction on the mmds of diluted malathion fogs: i.e., differences among flow rates depended on temperature and vice versa. PMID:8350082

  15. Fog, Clouds and the Maintenance of Ecosystems: Mist Opportunities?

    NASA Astrophysics Data System (ADS)

    Weathers, K. C.

    2006-12-01

    What is the significance of occult precipitation-- otherwise known as fog or cloud water (terms used interchangeably here)--in the maintenance of ecosystems? More than a century of natural history observations and decades of research have demonstrated that occult precipitation does deliver water, nutrients, and pollutants to coastal and montane ecosystems, but that its ecological importance is likely to vary by ecosystem. Still, many key ecological questions about the role of fog in the maintenance of ecosystems remain unanswered: For example, what is the effect of fog water and nutrient inputs on annual productivity or rates of nutrient cycling? Are soil processes affected by fog water input to ecosystems? To what extent do plants or animals actually use cloud or fog-delivered nutrients, and if they do, what are the mechanisms? Does fog input control the distribution and abundance of plant and/or animal species? If so, are the mechanisms hydrologic, physical (i.e., influence on temperature or light) and/or nutrient based? Although many of the early observations and research suggested that the delivery of water was one of the more important roles of fog in ecosystem maintenance, we and others have demonstrated that nutrient, as well as pollutants in fog are often 3-10x more concentrated than rain water, and can range up to 100x more concentrated. In some ecosystems, such as old growth forests on Chiloe Island, Chile, we have shown that comparatively large nutrient (e.g., nitrogen) loads can be delivered to ecosystems via a small amount (10s of cms/year) of fog water deposition. Thus, a little fog water has the potential to influence ecosystem processes. In addition, we have hypothesized that "the ocean may be feeding the forest," i.e., the source of the nutrients in fog water may be the ocean. In contrast to this fog subsidy, the ecological function of some high-elevation forests in the northeastern United States has been shown to be negatively impacted, in part

  16. Effects of synoptic-scale circulation pattern and local land surface condition on fog at Kushiro, northern Japan

    NASA Astrophysics Data System (ADS)

    Sugimoto, S.; Sato, T.; Nakamura, K.

    2012-12-01

    NPH is a crucial factor for low FF because the northward moisture transport toward Kushiro changes in connection with moisture supply along the monsoon westerly. In other words, the recent decline in summer FF around Kushiro is chiefly caused by changes in the NPH behavior. According to the visibility observation at Kushiro, hourly FF increases in the midnight, has a maximum peak in early morning, and decreases from morning to noon. This diurnal variation, i.e. decrease of the fog/LC frequency from early morning to noon, was identified around Kushiro from the visible and infrared satellite images during 2007-2009 from May to September. The fog/LC frequency differs depending on the land use and is 5-7.5 % higher over the wetland than that over the city area. The sensitivity experiments changing land use from the wetland to the city shows that the migrated sea fog dissipates during nighttime due to a heating effect in the city caused by increase of sensible heat fluxes from surface. During early morning, fog dissipation is more enhanced by a dry atmospheric condition due to a reducing of latent heat fluxes. The heterogeneity of sea fog distribution around Kushiro is attributed to fog dissipation over the city and fog regeneration or recondensation over the wetland, which are induced by a condition of sensible and latent heat fluxes associated with land use.

  17. Warm fog dispersal

    NASA Technical Reports Server (NTRS)

    Frost, W.

    1983-01-01

    The charged particle generator was further tested after some design modification. The generator performance was measured with additional instrumentation and found to confirm previous measurements. Plans for a field testing were than developed. The overall status of the program and the field test plans were presented to a group of atmospheric scientists and electrostatic experts at the NASA/MSFC sponsored USRA Workshop on Electrostatic Fog Dispersal at NCAR, Boulder, Colorado discussed in previous sections. The recommendations from this workshop are being evaluated as to whether NASA should proceed with the field test or whether further theoretical research on the phenomenon of electrostatic fog dispersal and additional development of the charged particle generator should be carried out. Information obtained from the USRA Workshop clearly identified three physical mechanisms that could possibly influence the fog dispersal process, which heretofore have not been considered, and which may provide additional insight to the direction of further fog dispersal work. These mechanisms are: the effect of corona discharge on the electric field strength at the surface, the influx of fog into the cleared volume by turbulent diffusion, and the increase in supersaturation as liquid water is removed, activating haze particles, and thus generating more fog. Plans are being formulated to investigate these mechanisms.

  18. Radiation fog and urban climate

    SciTech Connect

    Sachweh, M.; Koepke, P.

    1995-05-01

    Fog data of Southern Germany from the period 1949-1990 indicate a significant urban influence on fog frequency. An increase of the urban building density is connected with a reduction in the average number of fog days, which is interpreted as an effect of the urban heat island and moisture deficit. Feedback mechanisms which intensify the urban-rural contrast are discussed. The results are transferable to large cities with relatively good air quality.

  19. Environmental effects of fog oil and CS usage at the Combat Maneuver Training Center, Hohenfels, Germany. [2-chlorophenylmethylene

    SciTech Connect

    Brubaker, K.L.; Rosenblatt, D.H.; Snyder, C.T.

    1992-03-01

    In response to environmental concerns at the Combat Maneuver Training Center (CMTC), Hohenfels, Germany, the US Army 7th Army Training Command commissioned a scientific study by Argonne National Laboratory to investigate specific issues. The study involved three parts: (1) a field study to determine if fog oil and CS (a compound named after its discoverers, B.B. Carson and R.W. Stoughton) were accumulating in the CMTC environment, (2) a screening of selected soil samples for the presence of US Environmental Protection Agency priority pollutants, and (3) a literature review of the health effects of fog oil and CS, as well as a review of training practices at CMTC. No fog oil or fog oil degradation products were detected in any soil, sediment, or vegetation sample collected at CMTC. Trace quantities of one or more priority pollutants were tentatively detected in three of eight soil and sediment samples. However, the priority pollutant concentrations are so low that they pose no environmental or health hazards. No evidence of widespread or significant contamination in the training areas was found. Crucial data needed to fully evaluate both acute and chronic health effects of civilian exposures to CS at CMTC are not available. On the basis of the available literature, long-ten-n health effects in the civilian population near CMTC that could result from the use of fog oil and CS during training activities are believed to be negligible.

  20. Investigation of the effects of acid deposition upon California crops. Final report, 8 January 1986-7 July 1987

    SciTech Connect

    Olszyk, D.M.; Musselman, R.C.; Bytnerowicz, A.; Takemoto, B.K.

    1987-12-01

    This study evaluated the effects of acidic fog on winter crops of the San Joaquin Valley (alfalfa, broccoli, carrot, onion, potato, and wheat), and spring crops of the South Coast Air Basin (alfalfa, celery, green pepper, strawberry, and tomato). The study also evaluated the interaction between acidic fog and ambient oxidants on the crops of the South Coast. For the spring study, fog at pH 1.68, 2.69, or 7.24 was applied twice weekly to potted plants grown in open top field chambers or air exclusion plots for seven weeks. Fog at pH 1.68 caused necrosis on leaves and fruit of all species. Season long exposure to pH 1.68 fog reduced yield in strawberry, tomato, green pepper, and alfalfa. Species differed widely in their sensitivity to acidic fog.

  1. Optimization of strawberry disinfection by fogging of a mixture of peracetic acid and hydrogen peroxide based on microbial reduction, color and phytochemicals retention.

    PubMed

    Van de Velde, Franco; Vaccari, María Celia; Piagentini, Andrea Marcela; Pirovani, María Élida

    2016-09-01

    The fogging of strawberries using a environmentally friendly sanitizer mixture of peracetic acid (5%) and hydrogen peroxide (20%) was performed in a model chamber and modeled as a function of the concentration (3.4, 20.0, 60.0, 100.0 and 116.6 µL sanitizer L(-) (1) air chamber) and the treatment time (5.7, 15.0, 37.5, 60.0 and 69.3 min). The sanitizer fogging was adequate for reducing total mesophilic microbial and yeasts and moulds counts of fruits until seven days of storage at 2℃. However, sanitizer oxidant properties adversely affected the content of total anthocyanins, total phenolics, vitamin C, and antioxidant capacity to various degrees, with some deleterious changes in the fruits color, depending on the fogging conditions. A multiple numeric response optimization was developed based on 2.0 log microbiological reduction, maximum phytochemicals and antioxidant capacity retentions, with no changes in the fruits color, being the optimal fogging conditions achieved: 10.1 µL sanitizer L(-1) air chamber and 29.6 min. The fogging of strawberries at these conditions may represent a promising postharvest treatment option for extending their shelf-life without affecting their sensory quality and bioactive properties.

  2. Optimization of strawberry disinfection by fogging of a mixture of peracetic acid and hydrogen peroxide based on microbial reduction, color and phytochemicals retention.

    PubMed

    Van de Velde, Franco; Vaccari, María Celia; Piagentini, Andrea Marcela; Pirovani, María Élida

    2016-09-01

    The fogging of strawberries using a environmentally friendly sanitizer mixture of peracetic acid (5%) and hydrogen peroxide (20%) was performed in a model chamber and modeled as a function of the concentration (3.4, 20.0, 60.0, 100.0 and 116.6 µL sanitizer L(-) (1) air chamber) and the treatment time (5.7, 15.0, 37.5, 60.0 and 69.3 min). The sanitizer fogging was adequate for reducing total mesophilic microbial and yeasts and moulds counts of fruits until seven days of storage at 2℃. However, sanitizer oxidant properties adversely affected the content of total anthocyanins, total phenolics, vitamin C, and antioxidant capacity to various degrees, with some deleterious changes in the fruits color, depending on the fogging conditions. A multiple numeric response optimization was developed based on 2.0 log microbiological reduction, maximum phytochemicals and antioxidant capacity retentions, with no changes in the fruits color, being the optimal fogging conditions achieved: 10.1 µL sanitizer L(-1) air chamber and 29.6 min. The fogging of strawberries at these conditions may represent a promising postharvest treatment option for extending their shelf-life without affecting their sensory quality and bioactive properties. PMID:26769132

  3. La Jolla Fog Study

    NASA Astrophysics Data System (ADS)

    Roberts, G. C.; Ramana, M.; Pham, A.; Ramanathan, V.

    2002-12-01

    The Center for Atmospheric Sciences at the Scripps Institution of Oceanography conducted a ground-based experiment to study fog/marine-stratus clouds over the San Diego region during the summer months of 2002. The purpose of the experiment is to understand aerosol/cloud interactions and how they might influence cloud radiative properties and precipitation. We operated several instruments on Mt. Soledad to study aerosol and cloud properties. These instruments include a forward scattering spectrometer probe (FSSP-100) and an aerosol particle sizer (APS) to measure the cloud droplet spectra during fog events, condensation particle counters to determine total aerosol concentrations, cloud condensation nuclei counters to understand aerosol/cloud droplet interactions, a scanning mobility particle sizer (SMPS) to determine dry aerosol number size distributions, and a weather station to relate fog events to local meteorology. Aerosol concentrations showed a diel variation with high and variable particle concentrations during the day, which often were greater than 104 cm-3. Nighttime concentrations were lower (i.e., several thousand cm-3) and exhibited less variation than daytime values. In general, aerosol concentrations do not appear to be correlated to droplet concentrations indicating that local anthropogenic sources may not have a large influence on the coastal fog. Two types of events (haze and fog) have been characterized during this study based on the droplet distribution. A haze event was dominated by droplets less than 5 μm diameter and sometimes exceeded droplet concentrations of 1000 cm-3. There were virtually no particles larger than 5 micron diameter during these events. A fog event was characterized by larger droplets with droplets greater than 5 μm diameter accounting for a bulk of the number concentration. The average effective radius during these fog events was about 5 μm and the droplet concentration rarely exceeded 100 cm-3. On several occasions, a

  4. Effects of thinning on throughfall in Canary Islands pine forest — the role of fog

    NASA Astrophysics Data System (ADS)

    Aboal, J. R.; Jiménez, M. S.; Morales, D.; Gil, P.

    2000-12-01

    Throughfall was monitored over a one-year period in a 48-year-old Pinus canariensis plantation on the northern side of the island of Tenerife, nine years after light thinning (mean 15% of basal area (BA)) or heavy thinning (mean 56% of BA). Three plots of each treatment (light thinning, heavy thinning, no thinning) were studied, using a randomized block design. Mean total throughfall over the year of study was about 2.0 times the incident rainfall in the control plots, about 2.2 times rainfall in the lightly thinned plots, and about 1.8 times incident rainfall in the heavily thinned plots. The high throughfall-to-rainfall ratios are as expected, given the importance of fog entrapment in these forests. The statistical analysis indicated that the observed differences in throughfall are attributable to the treatments, not to plot topography. Throughfall showed significant relationships with actual BA, surface roughness (as tree height variability) and leaf area index (LAI), all of which varied significantly among treatments (as expected). Our results are unexpected as heavy thinning led to a long-term decline, not increase, in throughfall. The explanation for this result is the importance of fog entrapment may mean that reducing LAI and surface roughness (height variability) has a negative effect on throughfall. The long period elapsed between thinning and throughfall estimation means that LAI of light thinning plots exceeded pre-thinning values, and then throughfall values.

  5. Asymmetric ratchet effect for directional transport of fog drops on static and dynamic butterfly wings.

    PubMed

    Liu, Chengcheng; Ju, Jie; Zheng, Yongmei; Jiang, Lei

    2014-02-25

    Inspired by novel creatures, researchers have developed varieties of fog drop transport systems and made significant contributions to the fields of heat transferring, water collecting, antifogging, and so on. Up to now, most of the efforts in directional fog drop transport have been focused on static surfaces. Considering it is not practical to keep surfaces still all the time in reality, conducting investigations on surfaces that can transport fog drops in both static and dynamic states has become more and more important. Here we report the wings of Morpho deidamia butterflies can directionally transport fog drops in both static and dynamic states. This directional drop transport ability results from the micro/nano ratchet-like structure of butterfly wings: the surface of butterfly wings is composed of overlapped scales, and the scales are covered with porous asymmetric ridges. Influenced by this special structure, fog drops on static wings are transported directionally as a result of the fog drops' asymmetric growth and coalescence. Fog drops on vibrating wings are propelled directionally due to the fog drops' asymmetric dewetting from the wings.

  6. Effects of various runway lighting parameters upon the relation between runway visual range and visual range of centerline and edge lights in fog

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1973-01-01

    Thirty six students and 54 commercial airline pilots were tested in the fog chamber to determine the effect of runway edge and centerline light intensity and spacing, fog density, ambient luminance level, and lateral and vertical offset distance of the subject from the runway's centerline upon horizontal visual range. These data were obtained to evaluate the adequacy of a balanced lighting system to provide maximum visual range in fog viewing both centerline and runway edge lights. The daytime system was compared against two other candidate lighting systems; the nighttime system was compared against other candidate lighting systems. The second objective was to determine if visual range is affected by lights between the subject and the farthestmost light visible through the fog. The third objective was to determine if college student subjects differ from commercial airline pilots in their horizontal visual range through fog. Two studies were conducted.

  7. Fog water chemistry in Shanghai

    NASA Astrophysics Data System (ADS)

    Li, Pengfei; Li, Xiang; Yang, Chenyu; Wang, Xinjun; Chen, Jianmin; Collett, Jeffrey L., Jr.

    2011-08-01

    With the aim of understanding the fog chemistry in a Chinese megacity, twenty-six fog water samples were collected in urban Shanghai from March 2009 to March 2010. The following parameters were measured: pH, electrical conductivity (EC), ten inorganic major ions ( SO42-, NO3-, NO2-, F -, Cl -, Na +, K +, Ca 2+, Mg 2+, NH4+) and four major organic acids (CH 3COO -, HCOO -, CO42-, MSA). The total ionic concentration (TIC) and EC of fog samples were one or two orders of magnitude higher than those often found in Europe, North America and other Asian countries. Pollutants were expected to be mainly from local sources, including factories, motor vehicle emissions and civil construction. Non-local sources such as moderate- and long-range transport of sea salt also contributed to pollution levels in fog events as indicated by back trajectory analysis. The pH of the fog water collected during the monitoring period varied from 4.68 to 6.58; acidic fogs represented about 30.8% of the total fog events during this period. The fog water was characterized by high concentrations of SO42- (20.0% of measured TIC), NO3- (17.1%), NH4+ (28.3%) and Ca 2+ (14.4%). SO42- and NO3-, the main precursors of fog acidity, were related to burning fossil fuels and vehicle emissions, respectively. NH4+, originating from the scavenging of gaseous ammonia and particulate ammonium nitrate and ammonium sulfate, and Ca 2+, originating from the scavenging of coarse particles, acted as acid neutralizers and were the main cause for the relatively high pH of fogs in Shanghai. The ratio of ( SO42- + NO3-)/( NH4+ + Ca 2+) was lower than 1, indicating the alkaline nature of the fog water. A high ratio of NO3-/ SO42- and low ratio of HCOO -/CH 3COO - were consistent with large contributions from vehicular emissions that produce severe air pollution in megacities.

  8. Fog dispersion. [charged particle technique

    NASA Technical Reports Server (NTRS)

    Christensen, L. S.; Frost, W.

    1980-01-01

    The concept of using the charged particle technique to disperse warm fog at airports is investigated and compared with other techniques. The charged particle technique shows potential for warm fog dispersal, but experimental verification of several significant parameters, such as particle mobility and charge density, is needed. Seeding and helicopter downwash techniques are also effective for warm fog disperals, but presently are not believed to be viable techniques for routine airport operations. Thermal systems are currently used at a few overseas airports; however, they are expensive and pose potential environmental problems.

  9. Ion Composition of Fog Water and Its Relation to Air Pollutants during Winter Fog Events in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Yang, Jun; Xie, Yu-Jing; Shi, Chun-E.; Liu, Duan-Yang; Niu, Sheng-Jie; Li, Zi-Hua

    2012-05-01

    Intensive field experiments focused on fog chemistry were carried out in the northern suburb of Nanjing during the winters of 2006 and 2007. Thirty-seven fog water samples were collected in nine fog events. Based on the chemical analysis results of those samples and the simultaneous measurements of air pollution gases and atmospheric aerosols, the chemical characteristics of fog water and their relations with air pollutants during fog evolution were investigated. The results revealed an average total inorganic ionic concentration TIC = 21.18 meq/L, and the top three ion concentrations were those of SO4 2-, NH4 + and Ca2+ (average concentrations 6.99, 5.95, 3.77 meq/L, respectively). However, the average pH value of fog water was 5.85, which is attributable to neutralization by basic ions (NH4 + and Ca2+). The average TIC value of fog water measured in advection-radiation fog was around 2.2 times that in radiation fog, and the most abundant cation was NH4 + in advection-radiation fog and Ca2+ in radiation fog. In dense fog episodes, the concentration variations of primary inorganic pollution gases showed a "V"-shaped pattern, while those of volatile organic compounds (VOCs) displayed a "Λ"-shaped pattern. The dense fog acted as both the source and sink of atmospheric aerosol particles; fog processes enhanced particle formation, leading to the phenomenon that the aerosol concentration after fog dissipation was higher than that before the fog, and at the same time, mass concentration of PM10 reached the lowest value in the late stage of extremely dense fog episodes because of the progressive accumulated effect of wet deposition of large fog droplets. Both air pollution gases and aerosols loading controlled the ion compositions of fog water. The Ca2+ in fog water originated from airborne particles, while SO4 2- and NH4 + were from both heterogeneous production and soluble particulate species.

  10. Hydrologic Effects and Biogeographic Impacts of Coastal Fog, Channel Islands, California

    NASA Astrophysics Data System (ADS)

    Fischer, D. T.; Still, C. J.; Williams, A. P.

    2006-12-01

    Fog has long been recognized as an important component of the hydrological cycle in many ecosystems, including coastal desert fog belts, tropical cloud forests, and montane areas worldwide. Fog drip can be a major source of water, particularly during the dry season, and there is evidence in some ecosystems of direct fogwater uptake by foliar absorption. Fog and low clouds can also increase availability of water by reducing evaporative water losses. In the California Channel Islands, fog and low stratus clouds dramatically affect the water budget of coastal vegetation, particularly during the long summer drought. This work focuses on a population of Bishop pine (Pinus muricata D. Don) on Santa Cruz Island. This is the southernmost large stand of this species, and tree growth and survival appears to be strongly limited by water availability. We have used parallel measurement and modeling approaches to quantify the importance of fogwater inputs and persistent cloud cover to Bishop pine growth. We have modeled drought stress over the last century based on local climate records, calibrated against a dense network of 12 weather stations on a 7km coastal-inland elevation gradient. Water availability is highly variable year to year, with episodic droughts that are associated with widespread tree mortality. Frequent cloud cover near the coast reduces evapotranspiration relative to the inland site (on the order of 25%), thereby delaying the onset of, and moderating the severity of the annual summer drought. Substantial summer fog drip at higher elevations provides additional water inputs that also reduce drought severity. Beyond the theoretical availability of extra water from fog drip, tree ring analysis and xylem water isotopic data suggest that significant amounts of fog water are actually taken up by these trees. Stand boundaries appear to be driven by spatial patterns of mortality related to water availability and frequency of severe drought. These results suggest that

  11. Short-term effects of military fog oil on the fountain darter (Etheostoma fonticola).

    PubMed

    Ryan, T A; Kohl, A N; Soucek, D J; Smith, T S; Brandt, T M; Bonner, T H; Cropek, D M

    2013-11-01

    Toxicity tests evaluated chronic and sublethal effects of fog oil (FO) on a freshwater endangered fish. FO is released during military training as an obscurant smoke that can drift into aquatic habitats. Fountain darters, Etheostoma fonticola, of four distinct life stages were exposed under laboratory conditions to three forms of FO. FO was vaporized into smoke and allowed to settle onto water, violently agitated with water, and dosed onto water followed by photo-oxidization by ultraviolet irradiation. Single smoke exposures of spawning adult fish did not affect egg production, egg viability, or adult fish survival in 21-day tests. Multiple daily smoke exposures induced mortality after 5 days for larvae fish. Larvae and juvenile fish were more sensitive than eggs in 96-h lethal concentration (LC50) tests with FO–water mixtures and photo-oxidized FO. Water-soluble FO components photo-modified by ultraviolet radiation were the most toxic, thus indicating the value of examining weathering and aging of chemicals for the best determination of environmental impact.

  12. Effects of fog, driver experience and gender on driving behavior on S-curved road segments.

    PubMed

    Li, Xiaomeng; Yan, Xuedong; Wong, S C

    2015-04-01

    Driving on curved roads has been recognized as a significant safety issue for many years. However, driver behavior and the interactions among variables that affect driver performance on curves is complicated and not well understood. Previous studies have investigated various factors that influence driver performance on right- or left-turn curves, but have paid little attention to the effects of foggy weather, driver experience and gender on driver performance on complex curves. A driving simulator experiment was conducted in this study to evaluate the relationships between driving behavior on a continuous S-curve and foggy weather, driver experience and gender. The process of negotiating a curve was divided into three stages consisting of a straight segment, the transition from the straight segment to the S-curve and the S-curve. The experimental results indicated that drivers tended to drive more cautiously in heavy fog, but the driving risk was still increased, especially in the transition stage from the straight segment to the S-curve. The non-professional (NP) drivers were less sensitive to the impending change in the road geometry, and less skilled in both longitudinal and lateral vehicle control than the professional drivers. The NP female drivers in particular were found to be the most vulnerable group in S-curve driving.

  13. Scavenging of urban air emissions by Fog at Delhi, India

    NASA Astrophysics Data System (ADS)

    Saxena, P.; Kulshrestha, U. C.

    2015-12-01

    The present study focuses upon the understanding of fog water chemistry in Delhi city. Total seventy fog water samples were collected at two different sites in Delhi during December 2014 to March 2015. Selected parameters such as pH, major anions (Cl-, F-, NO3- and SO42-) and major cations (NH4+, K+, Ca2+, Mg2+, Na+) were determined in the samples. The pH of the fog water collected during the monitoring period at Site I (traffic intersection) varied from 4.68 to 5.58 indicating the acidic nature of fog water while at the site II (green cover area), it ranged from 6.11 to 6.88 having slightly lower acidity. At the Site I, the average concentration of Cl-, Na+, SO42-, NH4+ was recorded as 1.5 X 10-2, 8 X 10-3, 4 X 10-3 and 1 X 10-2 μEqu/L respectively. Such values of ionic species may be attributed to the local sources, including factories, motor vehicle emissions and civil construction etc. However, non-local sources such as moderate- and long-range transport of sea salt also had significant influence on ionic content of fog water. In general the Na+ ratio values were found to be higher side suggesting the influence of non-marine sources. Extremely high values of Cl-/ Na+ ratios indicated the contribution from combustion of organochlorine compounds. Hence, the higher ratios of inorganic ions and acidic pH revealed that fog is an effective mechanism for the scavenging of various pollutants emitted by different sources in the city.

  14. Influence of aqueous chemistry on the chemical composition of fog water and interstitial aerosol in Fresno

    NASA Astrophysics Data System (ADS)

    Kim, Hwajin; Ge, Xinlei; Collier, Sonya; Xu, Jianzhong; Sun, Yele; Wang, Youliang; Herckes, Pierre; Zhang, Qi

    2015-04-01

    A measurement study was conducted in the Central Valley (Fresno) of California in January 2010, during which radiation fog events were frequently observed. Fog plays important roles in atmospheric chemistry by scavenging aerosol particles and trace gases and serving as a medium for various aqueous-phase reactions. Understanding the effects of fog on the microphysical and chemical processing of aerosol particles requires detailed information on their chemical composition. In this study, we characterized the chemical composition of fog water and interstitial aerosol particles to study the effects of fog processing on aerosol properties. Fog water samples were collected during the 2010 Fresno campaigns with a Caltech Active Strand Cloud water Collector (CASCC) while interstitial submicron aerosols were characterized in real time with an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a scanning Mobility Particle Sizer (SMPS). The fog water samples were later analyzed using the HR-ToF-AMS, ion chromatography, and a total carbon analyzer. The chemical composition and characteristics of interstitial particles during the fog events were compared to those of dissolved inorganic and organic matter in fog waters. Compared to interstitial aerosols, fog water is composed of a higher fraction of ammonium nitrate and oxygenated organics, due to aqueous formation of secondary aerosol species as well as enhanced gas-to-particle partitioning of water soluble species under water rich conditions. Sulfate is formed most efficiently in fog water although its contribution to total dissolved mass is relatively low. The HR-ToF-AMS mass spectra of organic matter in fog water (FOM) are very similar to that of oxygenated organic aerosols (OOA) derived from positive matrix factorization (PMF) of the HR-ToF-AMS spectra of ambient aerosol (r2 = 0.96), but FOM appears to contain a large fraction of acidic functional groups than OOA. FOM is also enriched of

  15. Fog/cloud and rain chemistry in northern coastal California

    SciTech Connect

    Bicknell, S.H.; Lemcke, S.

    1987-07-01

    Fog, clouds and rain were sampled for 2 years at Redwood National Park (RNP) and one year at Arcata and Oakland. Fog and cloud water samples were more acidic and contained higher concentrations of Ca, Mg, K, Na, NH4, SO4, NO3 and Cl, than rain samples at all sites. Cloud/fog water and rain sample chemistry was not different for RNP and Arcata; but Oakland samples were significantly more acid and had higher concentrations of all elements. RNP and Arcata cloud/fog samples were more acid and contained higher elemental concentrations than expected under pristine conditions. Average pH's were: RNP cloud/fog - 4.12, RNP rain - 4.63, Arcata cloud/fog - 4.00, Arcata rain - 4.66, Oakland cloud/fog - 3.87, Oakland rain - 4.37.

  16. Fog chemistry in the Texas-Louisiana Gulf Coast corridor

    NASA Astrophysics Data System (ADS)

    Raja, Suresh; Raghunathan, Ravikrishna; Yu, Xiao-Ying; Lee, Taehyoung; Chen, Jing; Kommalapati, Raghava R.; Murugesan, Karthik; Shen, Xinhua; Qingzhong, Yuan; Valsaraj, Kalliat T.; Collett, Jeffrey L.

    Fog samples were collected in two population centers of the US Gulf Coast (Houston, Texas and Baton Rouge, Louisiana) using Caltech active strand cloud collectors. A total of 32 fogwater samples were collected in Baton Rouge (November 2004-February 2005) and Houston (February 2006). These samples were analyzed for pH, total and dissolved organic carbon, major inorganic ions, and a variety of organic compounds including organic acids, aromatics, carbonyls, and linear alkanes. Fogs in both environments were of moderate density, with typical fog liquid water contents <100 mg m -3. Fog samples collected in Houston reflect a clear influence of marine and anthropogenic inputs, while Baton Rouge samples also reflect agricultural inputs. The volume-weighted mean fog pH was somewhat more acidic (˜4.3) in Houston than in Baton Rouge (˜5.0). A wide pH range was observed in fog at both locations. Houston fog had higher concentrations of Cl -, NO 3-, Na +, Mg 2+, and Ca 2+. Sulfate to nitrate ratios were high in fogs at both locations, typical of many clouds in the eastern US. Total organic carbon concentrations were much higher in Houston fogs than in Baton Rouge fogs. Efforts to speciate dissolved organic carbon (DOC) reveal large contributions from organic acids and carbonyls, with smaller contributions from other organic compound families including aromatics, alkanes, amides, and alcohols. Approximately 40% of the fog DOC was unspeciated in samples from both study locations.

  17. Marine fog: a review

    USGS Publications Warehouse

    Koračin, Darko; Dorman, Clive E.; Lewis, John M.; Hudson, James G.; Wilcox, Eric M.; Torregrosa, Alicia

    2014-01-01

    The objective of this review is to discuss physical processes over a wide range of spatial scales that govern the formation, evolution, and dissipation of marine fog. We consider marine fog as the collective combination of fog over the open sea along with coastal sea fog and coastal land fog. The review includes a history of sea fog research, field programs, forecasting methods, and detection of sea fog via satellite observations where similarity in radiative properties of fog top and the underlying sea induce further complexity. The main thrust of the study is to provide insight into causality of fog including its initiation, maintenance, and destruction. The interplay between the various physical processes behind the several stages of marine fog is among the most challenging aspects of the problem. An effort is made to identify this interplay between processes that include the microphysics of fog formation and maintenance, the influence of large-scale circulation and precipitation/clouds, radiation, turbulence (air-sea interaction), and advection. The environmental impact of marine fog is also addressed. The study concludes with an assessment of our current knowledge of the phenomenon, our principal areas of ignorance, and future lines of research that hold promise for advances in our understanding.

  18. Long-term observation of fog chemistry and estimation of fog water and nitrogen input via fog water deposition at a mountainous site in Hokkaido, Japan

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Takashi; Katata, Genki; Noguchi, Izumi; Sakai, Shigekatsu; Watanabe, Yoko; Uematsu, Mitsuo; Furutani, Hiroshi

    2015-01-01

    To evaluate water and nitrogen input via fog deposition, the fog water chemistry and deposition around a crater lake (Lake Mashu) in northern Japan were investigated in the growing seasons of trees (summer to autumn) in 2006-2012. The fog samples were collected using an active fog collector and droplet size distribution was measured with a droplet size spectrometer (FM-100). The visibility (VIS)-liquid water content of fog (LWC) relationship differed between summer and autumn. Large fog droplets decreased in autumn and the calculated LWC from FM-100 measurements (LWCobs) were lower than those in summer at the same VIS. Two empirical curves between LWCobs and VIS were obtained and used for better estimation of fog deposition. Fog deposition was calculated from LWC empirically derived from past VIS data and deposition velocity (Vd) estimated using wind speed and vegetation parameters. The mean pH of fog water was 4.6 and the percentage of samples of pH 4.0 or more was 93%. Compared to previous literature of exposure experiments of acid mist on plants, fog acidity in this study did not seem to injure plant leaves. The water input via fog deposition accumulated for each growing season was estimated at 107-140 mm, corresponding to 18-23% of the precipitation in the same period. Nitrogen deposition via fog deposition in a plant growing season was estimated at 26-30 meq m- 2 (3.6-4.2 kg N ha- 1). As a long-term trend, NO3- concentration in fog water decreased significantly. However, the long-term trends of fog and nitrogen depositions were not clear.

  19. Driving in fog: the effects of driving experience and visibility on speed compensation and hazard avoidance.

    PubMed

    Mueller, Alexandra S; Trick, Lana M

    2012-09-01

    Inexperience is one of the strongest predictors for collisions, but it remains unclear how novice drivers differ from experienced drivers in terms of safety-related behavioural adaptations such as speed reduction in the presence of reduced visibility. To investigate the influence of driving experience on behavioural compensations to fog, average speed, speed variability, steering variability, collision rate, and hazard response time were measured in a driving simulator. Experienced drivers drove faster in clear visibility than novice drivers, yet they reduced their speed more in reduced visibility so that both groups drove at the same speed in simulated fog. Compared to experienced drivers, novice drivers had higher hazard response times, greater speed and steering variability, and were the only drivers to have collisions.

  20. Acid fog Deposition of Crusts on Basaltic Tephra Deposits in the Sand Wash Region of Kilauea Volcano: A Possible Mechanism for Siliceous-Sulfatic Crusts on Mars

    NASA Astrophysics Data System (ADS)

    Schiffman, P.; Zierenberg, R.; Marks, N.; Bishop, J. L.

    2004-12-01

    Although the presence of sulfate minerals in martian outcrops may imply the prior existence of standing bodies of surface water, in terrestrial volcanic settings, sulfatic alteration may also occur above the water table within the vadose zone. On the summit of Kilauea volcano, sulfur dioxide, which is continuously emitted from Halemaumau crater and rapidly sequestered into sulfuric acid-rich aerosol entrained in the prevailing trade winds, is subsequently precipitated as acid-fog immediately downwind from the caldera in the Kau Desert. The characteristic pH of surface tephra deposits is < 4.0 in Sand Wash, a region of continuous, acidic aerosol fall-out immediately SW of the caldera. The upper portion of the Keanakakoi Ash tephra in Sand Wash, deposited in the late 18th century, has a ubiquitous, 0.1-0.2 mm-thick coating of amorphous silica. Conversely, vertical walls of unconsolidated tephra, exposed within small, dry gullies eroded into the ca. 3-4 m-thick Keanakakoi section at Sand Wash, are coated with ca. 0.5-1.0 mm-thick, mixed amorphous silica and jarosite-bearing crusts. Since these crusts are denuded from their outcrops during ephemeral, but probably annual flooding events in Sand Wash, we believe that they must accumulate rapidly. These crusts are apparently formed via an evaporative mechanism whereby acidic pore fluids, circulating in the upper few m's within the highly porous tephra, are wicked towards the walls of the gullies. Geochemical modeling of the crust-forming process implies that the sulfate formation via evaporation occurs subsequent to minimal interaction of acidic pore fluids with the basaltic tephra. This also suggests that the cycle from acid-fog fall-out to precipitation of the siliceous-sulfatic crusts must occur quite rapidly. Production of siliceous-sulfatic crusts via acid-fog alteration may also be occurring on Mars. The occurrence of evaporitic sulfate and silica at Sand Wash in Kilauea may serve as an example of how the jarosite

  1. Arctic Coastal Fog over Greenland Glaciers using an Improved MODIS Fog Detection Method and Ground Observations

    NASA Astrophysics Data System (ADS)

    Jiskoot, H.; Harvey, T.; Gilson, G.

    2015-12-01

    Annual breakup of sea ice causes fog in Arctic coastal regions, which can both reduce and enhance glacier melt. With progressive sea ice loss and increasing temperatures and atmospheric moisture in the Arctic, it is essential to determine the frequency and spatial extent of fog in order to understand its present and future effects on glacier mass balance. Previously, we determined Greenland coastal fog to peak with 15-25% of days in July. Here, we present the spatial and vertical extent of significant melt-season fog events over Greenland coastal glaciers and the ice sheet. To this end, we modified a MODIS fog/low stratus detection method by Bendix et al. (2005), with verification by weather and radiosonde data, timelapse and Landsat imagery, and independent fog classifications. Our fog-detection method uses MODIS Levels 1b and 2, processed in an ENVI-ArcGIS environment as follows: 1) visual examination and application of vegetation and snow indices; 2) initial fog/low stratus discrimination with novel band thresholds and cloud products; 3) verification using cloud phase/temperature products; 4) cleaning misclassified pixels; 5) calculating fog/low stratus optical and geometrical thickness; 6) final differentiation of fog from low stratus using edge-pixel detection, trend-surface fitting, and DEM filling. The end product consists of 500 m fog-mask pixel maps over Greenland, with minimum and maximum possible extents based on classification of fog versus low stratus. Our results show that fog can cover extensive areas of the Greenland ice masses. Persistent fog events in early, mid, and late melt-season were extracted for East Greenland using fog rim detection overlain on the GIMP DEM, the Randolph Glacier Inventory, and a coast shapefile. E.g., a 4 July 2002 fog event covers 4300-5000 km2 of ice, with a maximum inland extent of 85 km to an elevation of 1250 m asl. Fog thickness over ice is 20-800 m, but can be underestimated by >50 m compared to radiosonde data.

  2. Enhanced persistence of fog under illumination for carbon nanotube fog condensation nuclei

    NASA Astrophysics Data System (ADS)

    Banerjee, Saumyabrata; Tripathi, Sachchida N.; Das, Utpal; Ranjan, Raju; Jadhav, Nilesh; Singh, Vivek P.; Jariwala, Chinmay; Sonkar, Sumit; Sarkar, Sabyasachi

    2012-07-01

    Black carbon (BC) emissions have increased over South Asia and more persistent winter fogs are common during last decade. However, a physical mechanism connecting these two is still unknown. A significant fraction of BC is known to be in the form of carbon-nanotube (CNT). We have investigated the effects of two different sets of fog condensation nuclei, viz., inorganic salts (sodium chloride and ammonium sulphate) and BC (graphite and CNT) on the dissipation of chamber generated fog under dark and halogen lamp illuminated conditions at a controlled temperature, relative humidity, and fog condensation nuclei distribution. We found that, for inorganic salts, fog dissipates at a faster rate under illumination than in dark conditions showing similar trends for both sodium chloride and ammonium chloride. On the contrary, fog is found to be more persistent, for illuminated conditions, in the case of BC. Moreover, fog persistence is found to be more than twice for CNT compared to graphite in illuminated conditions. CNT is known to be an extremely effective absorber of light which leads to microscopic heating and subsequent evaporation which inhibits droplet growth. Small droplets have large residence time leading to longer fog persistence. This hitherto unknown mechanism may be responsible for persistent fog in India during last decade.

  3. Combined effects of expectations and visual uncertainty upon detection and identification of a target in the fog.

    PubMed

    Quétard, Boris; Quinton, Jean-Charles; Colomb, Michèle; Pezzulo, Giovanni; Barca, Laura; Izaute, Marie; Appadoo, Owen Kevin; Mermillod, Martial

    2015-09-01

    Detecting a pedestrian while driving in the fog is one situation where the prior expectation about the target presence is integrated with the noisy visual input. We focus on how these sources of information influence the oculomotor behavior and are integrated within an underlying decision-making process. The participants had to judge whether high-/low-density fog scenes displayed on a computer screen contained a pedestrian or a deer by executing a mouse movement toward the response button (mouse-tracking). A variable road sign was added on the scene to manipulate expectations about target identity. We then analyzed the timing and amplitude of the deviation of mouse trajectories toward the incorrect response and, using an eye tracker, the detection time (before fixating the target) and the identification time (fixations on the target). Results revealed that expectation of the correct target results in earlier decisions with less deviation toward the alternative response, this effect being partially explained by the facilitation of target identification. PMID:26209302

  4. Combined effects of expectations and visual uncertainty upon detection and identification of a target in the fog.

    PubMed

    Quétard, Boris; Quinton, Jean-Charles; Colomb, Michèle; Pezzulo, Giovanni; Barca, Laura; Izaute, Marie; Appadoo, Owen Kevin; Mermillod, Martial

    2015-09-01

    Detecting a pedestrian while driving in the fog is one situation where the prior expectation about the target presence is integrated with the noisy visual input. We focus on how these sources of information influence the oculomotor behavior and are integrated within an underlying decision-making process. The participants had to judge whether high-/low-density fog scenes displayed on a computer screen contained a pedestrian or a deer by executing a mouse movement toward the response button (mouse-tracking). A variable road sign was added on the scene to manipulate expectations about target identity. We then analyzed the timing and amplitude of the deviation of mouse trajectories toward the incorrect response and, using an eye tracker, the detection time (before fixating the target) and the identification time (fixations on the target). Results revealed that expectation of the correct target results in earlier decisions with less deviation toward the alternative response, this effect being partially explained by the facilitation of target identification.

  5. An assessment of warm fog: Nucleation, control, and recommended research

    NASA Technical Reports Server (NTRS)

    Corrin, M. L.; Connell, J. R.; Gero, A. J.

    1974-01-01

    A state-of-the-art survey is given of warm fog research which has been performed up to, and including, 1974. Topics covered are nucleation, growth, coalescence, fog structures and visibility, effects of surface films, drop size spectrum, optical properties, instrumentation, liquid water content, condensation nuclei. Included is a summary of all reported fog modification experiments. Additional data is provided on air flow, turbulence, a summary of recommendations on instruments to be developed for determining turbulence, air flow, etc., as well as recommendations of various fog research tasks which should be performed for a better understanding of fog microphysics.

  6. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

    PubMed Central

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

  7. Effects of haze particles and fog droplets on NLOS ultraviolet communication channels.

    PubMed

    Xu, Changming; Zhang, Hongming; Cheng, Julian

    2015-09-01

    The performance of non-line-of-sight ultraviolet (UV) scattering communication depends largely on atmospheric parameters. In this paper, we consider haze, fog, two common types of aerosols, and introduce the density and size of aerosols as variables to study the channel path loss for the UV scattering communications. We modify a Monte-Carlo based multiple-scattering model and provide fitting functions to replace the complex calculations of Mie theory, which can be used to obtain the atmospheric coefficients and phase functions for the aerosols. Simulation results reveal that, given fixed elevation angles, the channel path loss is related to both communication range, the aerosol density, and size of aerosols. For a short communication range, an increase of aerosol density can reduce the path loss, which improves the performance of UV scattering communication. However, when the communication range is extended, the path loss will fall first and then rise with density of aerosols. This phenomenon also occurs for an increase of fog drop size. The density or size of aerosols that has the lowest path loss is inversely proportional to the communication range.

  8. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces.

    PubMed

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions-dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing.

  9. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces.

    PubMed

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions-dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

  10. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

    NASA Astrophysics Data System (ADS)

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-04-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing.

  11. One-year delayed effect of fog on malaria transmission: a time-series analysis in the rain forest area of Mengla County, south-west China

    PubMed Central

    Tian, Linwei; Bi, Yan; Ho, Suzanne C; Liu, Wenjie; Liang, Song; Goggins, William B; Chan, Emily YY; Zhou, Shuisen; Sung, Joseph JY

    2008-01-01

    Background Malaria is a major public health burden in the tropics with the potential to significantly increase in response to climate change. Analyses of data from the recent past can elucidate how short-term variations in weather factors affect malaria transmission. This study explored the impact of climate variability on the transmission of malaria in the tropical rain forest area of Mengla County, south-west China. Methods Ecological time-series analysis was performed on data collected between 1971 and 1999. Auto-regressive integrated moving average (ARIMA) models were used to evaluate the relationship between weather factors and malaria incidence. Results At the time scale of months, the predictors for malaria incidence included: minimum temperature, maximum temperature, and fog day frequency. The effect of minimum temperature on malaria incidence was greater in the cool months than in the hot months. The fog day frequency in October had a positive effect on malaria incidence in May of the following year. At the time scale of years, the annual fog day frequency was the only weather predictor of the annual incidence of malaria. Conclusion Fog day frequency was for the first time found to be a predictor of malaria incidence in a rain forest area. The one-year delayed effect of fog on malaria transmission may involve providing water input and maintaining aquatic breeding sites for mosquitoes in vulnerable times when there is little rainfall in the 6-month dry seasons. These findings should be considered in the prediction of future patterns of malaria for similar tropical rain forest areas worldwide. PMID:18565224

  12. Aqueous-phase photolysis of biacetyl (An α-dicarbonyl compound): A sink for biacetyl, and a source of acetic acid, peroxyacetic acid, hydrogen peroxide, and the highly oxidizing acetylperoxyl radical in aqueous aerosols, fogs, and clouds

    NASA Astrophysics Data System (ADS)

    Faust, Bruce C.; Powell, Kendall; Rao, C. Janakiram; Anastasio, Cort

    Aqueous-phase photolysis of biacetyl represents a heretofore uncharacterized sink for biacetyl and source of organic acids and peroxides to aqueous aerosols, and fog and cloud drops. The photolysis half-life of aqueous-phase biacetyl is approximately 1.0-1.6 h for a solar zenith angle of 36° (midday equinox sunlight in Durham, NC). Major products of aqueous biacetyl photolysis are acetic acid, peroxyacetic acid, and hydrogen peroxide. Pyruvic acid and methylhydroperoxide are minor photoproducts. Common atmospheric reductants (H-atom donors), such as formate, formaldehyde, glyoxal, phenol (as a model for phenolic compounds) and α- D-glucose (as a model for carbohydrates), substantially increase the quantum yields of peroxyacetic acid Formate also significantly increases the quantum yields of hydrogen peroxide. The highly oxidizing acetylperoxyl radical is proposed as a key intermediate in the photolysis of aqueous biacetyl. The sources and reactions of acetylperoxyl radicals in aqueous aerosols, fogs, and clouds should be investigated in future studies of atmospheric water-drop chemistry.

  13. Fog chemistry at an urban midwestern site

    SciTech Connect

    Muir, P.S.; Wade, K.A.; Carter, B.H.; Armentano, T.V.; Pribush, R.A.

    1986-12-01

    The Holcomb Research Institute is monitoring fog chemistry in Indianapolis, Indiana and at sites in and near the heavily industrialized Ohio River Valley. Results reported here indicate that fogs in this area can be strongly acidic, and that further studies are warranted. We report 1) the ionic composition of three fog events, samples collected in Indianapolis between December 1985 and February 1986, and 2) the pH of three additional events, samples collected between November 1985 and February 1986. (The volume of fog collected during the latter three events was insufficient for chemical analysis other than pH.) The pH of the fog samples ranged from 2.85 to 4.06; some of this fell within the range known to damage foliage and yield of some plant species. It has been demonstrated that even one exposure to highly acidic mists (pH par. delta 2.5) can damage certain crop species; hence, it is important to document the occurrence of any events having acidity near this level.

  14. Mechanisms of Fat, Oil and Grease (FOG) Deposit Formation in Sewer Lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    FOG deposits in sewer systems recently have been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. Batch tests were performed to elucidate ...

  15. AC fog withstand test on contaminated insulators by steam fog

    SciTech Connect

    Arai, J.N.

    1982-11-01

    This paper describes the results of an investigation into how steam fog parameters affect the withstand voltage of artificially contaminated insulators by the fog withstand method. Established the correlation between the steam flow rate and liquid water content of the fog. The fog withstand voltage showed a lower value with little dispersion at about 3 to 10 g/m/sup 3/ of the maximum liquid water content. The minimum fog withstand voltage agreed well with the minimum flashover voltage obtained under natural conditions. The authors suggest that, for the fog withstand test using steam fog, the ideal fog condition would be about 3 to 7 g/m/sup 3/ of the maximum liquid water content of the fog.

  16. Problems, control, and treatment of fat, oil, and grease (FOG): a review.

    PubMed

    Husain, Iman A F; Alkhatib, Ma'an Fahmi; Jammi, Mohamed Saedi; Mirghani, Mohamed E S; Bin Zainudin, Zaki; Hoda, Asif

    2014-01-01

    Presence of fat, oil, and grease (FOG) in wastewater is an ever-growing concern to municipalities and solid-waste facility operators. FOG enters the sewer system from restaurants, residences, and industrial food facilities. Its release into the sewer system results in a continuous build-up that causes eventual blockage of sewer pipes. Several researchers have investigated FOG deposition based on the local conditions of sewers and lifestyle. This paper attempts to review the physical and chemical characteristics of FOG, sources of FOG, and potential chemical and biological reactions of FOG. The effect of the aforementioned factors on the FOG-deposition mechanism is also discussed. Moreover, insight into the current control and treatment methods and potential reuse of FOG is highlighted. It is expected that this review would provide scientists and the concerned authorities a holistic view of the recent researches on FOG control, treatment, and reuse.

  17. Anti-Fog Compound

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Tracer Chemical Corporation's TRX Anti-Fog Composition is an inexpensive product which prevents condensation on plastic and glass surfaces. It was the result from a Tech Briefs article detailing a Johnson Space Center compound.

  18. Fog interception by Ball moss (Tillandsia recurvata)

    NASA Astrophysics Data System (ADS)

    Guevara-Escobar, A.; Cervantes-Jiménez, M.; Suzán-Azpiri, H.; González-Sosa, E.; Hernández-Sandoval, L.; Malda-Barrera, G.; Martínez-Díaz, M.

    2011-08-01

    Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (Cmin) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted by rain. T. recurvata contributed 20 % to the rain interception capacity of their shrub hosts: Acacia farnesiana and Prosopis laevigata and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, p = 0.048). The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h-1 to reach saturation conditions when fog was applied.

  19. Fixation and chemical analysis of single fog and rain droplets

    NASA Astrophysics Data System (ADS)

    Kasahara, M.; Akashi, S.; Ma, C.-J.; Tohno, S.

    Last decade, the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests, materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively, but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope, and SEX-EDX, particle-induced X-ray emission (PIXE) and micro-PIXE analyses, respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall.

  20. Diagnosing Antarctic Fog

    NASA Astrophysics Data System (ADS)

    Lazzara, M. A.

    2010-07-01

    Fog affects aviation and other logistical operations in the Antarctic; nevertheless limited studies have been conducted to understand fog behavior in this part of the world. A study has been conducted in the Ross Island region of Antarctica, the location of McMurdo Station and Scott Base - the main stations of the United States and New Zealand Antarctic programs, respectively. Using tools such as multi-channel satellites observations and supported by in situ radiosonde and ground-based automatic weather station observations, combined with back trajectory and mesoscale numerical models, discover that austral summer fog events are "advective" in temperament. The diagnosis finds a primary source region from the southeast over the Ross Ice Shelf (over 72% of the cases studied) while a minority of cases point toward a secondary fog source region to the north along the Scott Coast of the Ross Sea with influences from the East Antarctic Plateau. Part of this examination confirms existing anecdotes from forecasters and weather observers, while refuting others about fog and its behavior in this environment. This effort marks the beginning of our understanding of Antarctic fog behavior.

  1. Effects of ultrasonic and thermo-chemical pre-treatments on methane production from fat, oil and grease (FOG) and synthetic kitchen waste (KW) in anaerobic co-digestion.

    PubMed

    Li, Chenxi; Champagne, Pascale; Anderson, Bruce C

    2013-02-01

    The effects of ultrasonic and thermo-chemical pre-treatments on the methane production potential of anaerobic co-digestion with synthetic kitchen waste (KW) or fat, oil and grease (FOG) were investigated. Non-linear regressions were fitted to accurately assess and compare the methane production from co-digestion under the various pre-treatment conditions and to achieve representative simulations and predictions. Ultrasonic pre-treatment was not found to improve methane production effectively from either FOG co-digestion or KW co-digestions. Thermo-chemical pre-treatment could increase methane production yields from both FOG and KW co-digestions. COD solubilization was found to effectively represent the effects of pre-treatment. A comprehensive evaluation indicated that the thermo-chemical pre-treatments of pH=10, 55°C and pH=8, 55°C provided the best conditions to increase methane production from FOG and KW co-digestions, respectively. The most effective enhancement of biogas production (288±0.85mLCH(4)/g TVS) was achieved from thermo-chemically pre-treated FOG co-digestion, which was 9.9±1.5% higher than FOG co-digestion without thermo-chemical pre-treatment.

  2. Effects of ultra-low volume and thermal fog malathion, Scourge and naled applied against caged adult Culicoides furens and Culex quinquefasciatus in open and vegetated terrain.

    PubMed

    Linley, J R; Jordan, S

    1992-03-01

    The adulticidal effect of ULV and thermal fog malathion, Scourge and naled was tested at 2x label dosage (1.42, 0.22, 0.39 oz/acre, respectively) against caged Culicoides furens and Culex quinquefasciatus in open and vegetated (orange grove) terrain. Cages were at 122 cm elevation and positioned at 15.2, 45.7, 76.2, 106.7, 137.2 and 167.6 m from the line of insecticide release. Ultra-low volume applications of all 3 insecticides were markedly more effective than thermal fog under all conditions, especially in vegetated terrain. Of the 3 insecticides, malathion performed the poorest, especially against Cx. quinquefasciatus (in which there was some resistance) and particularly when applied as thermal fog. Scourge and naled were about equally effective. The best adulticide against C. furens was naled, which was clearly superior applied as ULV. It yielded 75% mortality out to 283 m in the open, and to 38 m in the presence of dense vegetation. PMID:1583493

  3. Fog, cloud, and dew chemistry. Final report

    SciTech Connect

    Hoffmann, M.R.

    1989-02-28

    The spatial and temporal variations of fog/cloud chemistry were determined in the San Joaquin Valley, in the Los Angeles Basin, and in the Santa Barbara Channel area using automated fog- and cloudwater collectors that were designed and constructed for the project. A significant correlation was observed between the average nighttime cloud- and fogwater loadings of H/sup +/ and NO/sub 3//sup /minus// and the maximum levels of O/sub 3//sup /minus//. Higher aldehydes, a series of dicarbonyls, and a variety of sulfonic acid salts formed by reaction of S(IV) and aldehydes were quantitatively determined in the droplet phase.

  4. Spray characterization of thermal fogging equipment typically used in vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The generation of insecticide laden fogs provides an effective method for controlling flying insects. One of the critical factors affecting the effectiveness of a thermal fogging application is the generation of droplets that will remain aloft in the fogging cloud and moves into the area where the ...

  5. Size-dependent particle activation properties in fog during the ParisFog 2012/13 field campaign

    NASA Astrophysics Data System (ADS)

    Hammer, E.; Gysel, M.; Roberts, G. C.; Elias, T.; Hofer, J.; Hoyle, C. R.; Bukowiecki, N.; Dupont, J.-C.; Burnet, F.; Baltensperger, U.; Weingartner, E.

    2014-04-01

    Fog causes a variety of hazards in road traffic, maritime navigation, as well as in air traffic and railway traffic. There is a great demand, e.g. from airports, for more reliable fog forecasts to prevent fog related accidents. Improved fog forecasts require a better understanding of the numerous complex mechanisms during the fog life cycle. During winter 2012/13 a field campaign called ParisFog aiming at fog research took place at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research). SIRTA is located about 20 km southwest of the Paris city centre, France in a semi-urban environment. In situ activation properties of the prevailing fog were investigated by measuring: (1) total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems; (2) interstitial hydrated aerosol and fog droplet size distributions at ambient conditions; (3) cloud condensation nuclei (CCN) number concentration at different supersaturations (SS) with a CCN counter. The aerosol particles were characterized regarding their hygroscopic properties, fog droplet activation behavior and contribution to light scattering for 17 developed fog events. Low particle hygroscopicity with an overall median of hygroscopicity parameter, κ, of 0.14 was found, likely caused by substantial influence from local traffic and wood burning emissions. Measurements of the aerosol size distribution at ambient RH revealed that the critical wet diameter, above which the hydrated aerosols activate to fog droplets, is rather large with a median value of 2.4 μm and is highly variable (ranging from 1 to 5 μm) between the different fog events. Thus, the number of activated fog droplets was very small and the non-activated hydrated particles were found to contribute siginificantly to the observed light scattering and thus to the reduction in visibility. Combining all experimental data, the effective peak supersaturation, SSpeak, a measure of the peak supersaturation

  6. Winter Frost and Fog

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This somewhat oblique blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 174 km (108 mi) diameter crater, Terby, and its vicinity in December 2004. Located north of Hellas, this region can be covered with seasonal frost and ground-hugging fog, even in the afternoon, despite being north of 30oS. The subtle, wavy pattern is a manifestation of fog.

    Location near: 28oS, 286oW Illumination from: upper left Season: Southern Winter

  7. Impact of activation process on fog life cycle

    NASA Astrophysics Data System (ADS)

    Mazoyer, Marie; Burnet, Frédéric; Lac, Christine; Roberts, Greg; Dupont, Jean-Charles; Haeffelin, Martial; Elias, Thierry

    2015-04-01

    Fogs are complex meteorological system dealing with fine scale processes. Subtle interaction between radiative, dynamic, turbulent and microphysic processes can lead to different fog life cycle, which make prediction difficult. The droplets that composed fogs are formed trough the activation of aerosol particles called CCN (cloud condensation nuclei) described by the Köhler theory (Köhler, 1936). The number and distribution of the droplets activated during fog formation is determined by the aerosols particles properties and number and the ambient vapor supersaturation of the atmosphere. In the frame of the PreViBOSS project, an in-situ measurement platform of fog properties at ground level was deployed at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research) during winter 2010 to 2013. Microphysics data supply a detailed characterization of number size spectrum from dry to wet aerosols particles and inform on the abilities of the aerosols particles to act as a CCN. 48 fog events have been studied. Supersaturation critical values and concentrations of CCN have been determined and linked to aerosols properties. The main impact of aerosols size distribution on activation have been pointed out. The study of droplets spectra evolution reveals the major physical processes into fogs and suggests that even if thermodynamic dominates the fog life cycle, activation process seems to have a significant effect. Large eddy simulation of fog run with Meso-NH model allow to explore precisely the interaction between fog physical processes and to quantify activation impact. Supersaturation modelling is a key point, a new pseudo-prognostic scheme (Thouron et al., 2012) is used. Confrontation between a detailed experimental study and three-dimensional fine scale simulation in LES provides an accurate investigation of the impact of activation process on fog life cycle.

  8. Fog interception by Ball moss (Tillandsia recurvata)

    NASA Astrophysics Data System (ADS)

    Guevara-Escobar, A.; Cervantes-Jiménez, M.; Suzán-Azpiri, H.; González-Sosa, E.; Hernández-Sandoval, L.; Malda-Barrera, G.; Martínez-Díaz, M.

    2010-03-01

    Interception losses are a major influence in the water yield of vegetated areas. For most storms, interception results in less water reaching the ground. However, fog drip or occult precipitation can result in negative interception because small drops are deposited on all plant surfaces and subsequently fall to the ground once vegetation storage capacities are exceeded. Fog drip is normally disregarded, but for some plant communities, it could be a mechanism offsetting evaporation losses. Tillandsia recurvata is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by T. recurvata was measured in controlled conditions through applying simulated rain or fog. The storage capacity was proportional to dry weight mass. Nocturnal stomatic opening in T. recurvata is not only relevant for CO2 but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543±77 vs. 325±56 mg, p=0.048). The coefficients obtained in the laboratory were used together with biomass measurements for T. recurvata in a xeric scrub to calculate the depth of water intercepted. Interception storage capacity (Cmin) was 0.19 and 0.54 mm for rainfall and fog respectively. T. recurvata contributed 20% to the rain interception of their shrub hosts: Acacia farnesiana and Prosopis laevigata. Meteorological data registered during one year at Cadereyta, México showed that radiative fog formation was possible during the dry season. The results showed the potential role of T. recurvata in capturing fog, which probably is a main source of water during the dry season that supports their reproductive and physiological activity at that time. The storage capacity of T. recurvata leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water

  9. Size-dependent particle activation properties in fog during the ParisFog 2012/13 field campaign

    NASA Astrophysics Data System (ADS)

    Hammer, E.; Gysel, M.; Roberts, G. C.; Elias, T.; Hofer, J.; Hoyle, C. R.; Bukowiecki, N.; Dupont, J.-C.; Burnet, F.; Baltensperger, U.; Weingartner, E.

    2014-10-01

    Fog-induced visibility reduction is responsible for a variety of hazards in the transport sector. Therefore there is a large demand for an improved understanding of fog formation and thus improved forecasts. Improved fog forecasts require a better understanding of the numerous complex mechanisms during the fog life cycle. During winter 2012/13 a field campaign called ParisFog aiming at fog research took place at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research). SIRTA is located about 20 km southwest of the Paris city center, France, in a semi-urban environment. In situ activation properties of the prevailing fog were investigated by measuring (1) total and interstitial (non-activated) dry particle number size distributions behind two different inlet systems; (2) interstitial hydrated aerosol and fog droplet size distributions at ambient conditions; and (3) cloud condensation nuclei (CCN) number concentration at different supersaturations (SS) with a CCN counter. The aerosol particles were characterized regarding their hygroscopic properties, fog droplet activation behavior and contribution to light scattering for 17 developed fog events. Low particle hygroscopicity with an overall median of the hygroscopicity parameter, κ, of 0.14 was found, likely caused by substantial influence from local traffic and wood burning emissions. Measurements of the aerosol size distribution at ambient RH revealed that the critical wet diameter, above which the hydrated aerosols activate to fog droplets, is rather large (with a median value of 2.6μm) and is highly variable (ranging from 1 to 5μm) between the different fog events. Thus, the number of activated fog droplets was very small and the non-activated hydrated particles were found to contribute significantly to the observed light scattering and thus to the reduction in visibility. Combining all experimental data, the effective peak supersaturation, SSpeak, a measure of the peak supersaturation during the fog

  10. The pioneer study of fog detection and horizontal precipitation measurement at subtropical highland of Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, P. H.; Lai, K. L.

    2010-07-01

    Heavy rainfall in highland caused by the interaction of tropical storms and sharp terrain is one of the major natural disasters in Taiwan. But there is no quantitative measurement on the fog and its horizontal precipitation (HP) to estimate the storage of water by plants in the highland region of Taiwan. In this pioneer study, we studied the fog detection and its horizontal precipitation amount, existence length and monthly variation at Kuan-Wu recreation area in Shei-Pa National Park of Taiwan. The 20-year (1988~2007) record length of meteorological data at Kuan-Wu was analyzed first to build up the background information of the local weather. The FDID (fog detection and interception device) including two fog detectors, two fog collectors and auto-shooting digital camera was delivered in this field program. The parallel experiment indoor with a fog tunnel also confirms the performance of polypropylene net used in FDID. FDID has collected data in the field over one year, and the preliminary results show that some components of FDID present the capability of fog event detection and give quantitative data of fog interception. The digital images in 5-min interval via fog collector data detected over 90% happening of fog event in the data available days. Through the RGB diagnosis in different pixel domains (different distances to the camera) on the digital images, the fog events are distinguished into light, medium and heavy fog events. The characteristics of daily and monthly variations of fog events could be explained through the terrain and local climate effects well. We also found the horizontal precipitation from fog provides ~11% extra water amount in the no-rain days. The happened possibility of fog & stratus cloud with The MTSAT geostationary IR channels by Central Weather Bureau is also validated by the FDID in-situ measurement. It shows that the remote sensing product of fog detection in nighttime has good correlation with FDID ground measurement.

  11. Fog Research: A Review of Past Achievements and Future Perspectives

    NASA Astrophysics Data System (ADS)

    Gultepe, I.; Tardif, R.; Michaelides, S. C.; Cermak, J.; Bott, A.; Bendix, J.; Müller, M. D.; Pagowski, M.; Hansen, B.; Ellrod, G.; Jacobs, W.; Toth, G.; Cober, S. G.

    2007-06-01

    The scientific community that includes meteorologists, physical scientists, engineers, medical doctors, biologists, and environmentalists has shown interest in a better understanding of fog for years because of its effects on, directly or indirectly, the daily life of human beings. The total economic losses associated with the impact of the presence of fog on aviation, marine and land transportation can be comparable to those of tornadoes or, in some cases, winter storms and hurricanes. The number of articles including the word ``fog'' in Journals of American Meteorological Society alone was found to be about 4700, indicating that there is substantial interest in this subject. In spite of this extensive body of work, our ability to accurately forecast/nowcast fog remains limited due to our incomplete understanding of the fog processes over various time and space scales. Fog processes involve droplet microphysics, aerosol chemistry, radiation, turbulence, large/small-scale dynamics, and surface conditions (e.g., partaining to the presence of ice, snow, liquid, plants, and various types of soil). This review paper summarizes past achievements related to the understanding of fog formation, development and decay, and in this respect, the analysis of observations and the development of forecasting models and remote sensing methods are discussed in detail. Finally, future perspectives for fog-related research are highlighted.

  12. Large volume water sprays for dispersing warm fogs

    NASA Astrophysics Data System (ADS)

    Keller, V. W.; Anderson, B. J.; Burns, R. A.; Lala, G. G.; Meyer, M. B.

    A new method for dispersing of warm fogs which impede visibility and alter schedules is described. The method uses large volume recycled water sprays to create curtains of falling drops through which the fog is processed by the ambient wind and spray-induced air flow; the fog droplets are removed by coalescence/rainout. The efficiency of this fog droplet removal process depends on the size spectra of the spray drops and optimum spray drop size is calculated as between 0.3-1.0 mm in diameter. Water spray tests were conducted in order to determine the drop size spectra and temperature response of sprays produced by commercially available fire-fighting nozzles, and nozzle array tests were utilized to study air flow patterns and the thermal properties of the overall system. The initial test data reveal that the fog-dispersal procedure is effective.

  13. Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

    PubMed

    He, Xia; Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J; de los Reyes, Francis L

    2011-05-15

    The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride. The calcium and fatty acid profile analysis showed that the laboratory-produced FOG deposit displayed similar characteristics to FOG deposits collected from sanitary sewer lines. Results of FTIR analysis showed that the FOG deposits are metallic salts of fatty acid as revealed by comparisons with FOG deposits collected from sewer lines and pure calcium soaps. Based on the data, we propose that the formation of FOG deposits occurs from the aggregation of excess calcium compressing the double layer of free fatty acid micelles and a saponification reaction between aggregated calcium and free fatty acids.

  14. UAV applications for thermodynamic profiling: Emphasis on ice fog research

    NASA Astrophysics Data System (ADS)

    Gultepe, Ismail; Heymsfield, Andrew J.; Fernando, Harindra J. S.; Hoch, Sebastian W.; Ware, Randolph

    2016-04-01

    Ice fog occurs often over the Arctic, cold climatic, and mountainous regions for about 30% of time where temperature (T) can go down to -10°C or below. Ice Nucleation (IN) and cooling processes play an important role by the controlling the intensity of ice fog conditions that affect aviation application, transportation, and local climate. Ice fog can also occur at T above -10°C but close to 0°C it occurs due to freezing of supercooled droplets that include an IN. To better document ice fog conditions, observations from the ice fog events of the Indirect and Semi-Direct Aerosol effects on Climate (ISDAC) project, Barrow, Alaska, Fog Remote Sensing And Modeling (FRAM) project Yellowknife, Northwest Territories, and the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) project, Heber City, Utah, were analyzed.. Measurements difficulties of small ice fog particles at cold temperatures and low-level flying restrictions prevent observations from aircraft within the surface boundary layer. However, unmanned Aerial Vehicles (UAVs) can be operated safely to measure IN number concentration, Relative Humidity with respect to ice (RHi), T, horizontal wind speed (Uh) and direction, and ice crystal spectra less than about 500 micron. Thermodynamic profiling by a Radiometrics Profiling Microwave Radiometer (PMWR) and Vaisala CL51 ceilometer was used to describe ice fog conditions in the vertical and its time development. In this presentation, ice fog characteristics and its thermodynamic environment will be presented using both ground-based and airborne platforms such as a UAV with new sensors. Some examples of measurements from the UAV for future research, and challenges related to both ice fog measurements and visibility parameterization will also be presented.

  15. Phosphorus input through fog deposition in a dry tropical forest

    NASA Astrophysics Data System (ADS)

    Vandecar, Karen L.; Runyan, Christiane W.; D'Odorico, Paolo; Lawrence, Deborah; Schmook, Birgit; Das, Rishiraj

    2015-12-01

    In many tropical forests, where phosphorus (P) is considered a limiting nutrient, atmospheric deposition can contribute significantly to available P. Previous studies have shown that P inputs from atmospheric deposition are enhanced by plant canopies. This effect is explained as the result of increased deposition of P-rich aerosol particles (dry deposition) and fog droplets (fog or "occult" deposition) onto leaf surfaces. Here we studied the importance of fog as a source of P to a P-limited dry tropical forest. Throughout an 80 day period during the dry season when fog is most common, we sampled fog water and bulk precipitation in a clearing and measured leaf wetness and throughfall in an adjacent secondary and mature forest stand. During the study period, total P (PT) concentrations in fog water ranged from 0.15 to 6.40 mg/L, on average fourteenfold greater than PT concentrations in bulk precipitation (0.011 to 0.451 mg/L), and sixfold and sevenfold greater than throughfall PT concentrations in the secondary and mature forest stands, respectively (0.007 to 1.319 mg/L; 0.009 to 0.443 mg/L). Based on leaf area index, the frequency of fog deposition, and amount of water deposited per fog event, we estimate that fog delivers a maximum of 1.01 kg/ha/yr to secondary forest stands and 1.75 kg/ha/yr to mature forest stands, compared to 0.88 kg/ha/yr to secondary forest stands and 1.98 kg/ha/yr to mature forest stands via throughfall (wet + dry deposition) and stemflow. Thus, fog deposition may contribute substantially to available P in tropical dry forests.

  16. Foi in Fog.

    NASA Astrophysics Data System (ADS)

    Occhionero, F.; Amendola, L.

    The authors discuss the observational constraints on the hypothesis that the large scale structure of our universe originates from primordial bubbles (PB's) and they present a viable toy model for the formation of PB's. They study a PB Spectrum (PBS) in the form of a power law because it is the natural outcome of First Order Inflation (FOI) and because it lends itself easily to numerical simulations of the Galaxy Correlation Function (GCF). The observed power law for the GCF can in fact be reproduced. The crucial test, represented by the observations of the isotropy and spectrum of the Cosmic Microwave Background, does place a severe constraint on the PBS. In search of an alternative physics, the authors study an example of a non-minimal generalization of Fourth Order Gravity (FOG). As in two field inflation PB's are produced copiously during the FOG slow roll, well before the end of inflation, and grow to interesting sizes.

  17. [Multiple scattering of visible and infrared light by sea fog over wind driving rough sea surface].

    PubMed

    Sun, Xian-Ming; Wang, Hai-Hua; Lei, Cheng-Xin; Shen, Jin

    2013-08-01

    The present paper is concerned with computing the multiple scattering characteristics of a sea fog-sea surface couple system within this context. The single scattering characteristics of sea fog were studied by Mie theory, and the multiple scattering of sunlight by single sea fog layer was studied by radiative transfer theory. The reflection function of a statistically rough ocean surface was obtained using the standard Kirchhoff formulation, with shadowing effects taken into account. The reflection properties of the combined sea fog and ocean surface were obtained employing the adding method, and the results indicated that the reflected light intensity of sea fog increased with the sea background.

  18. Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

    PubMed

    Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

    2016-05-23

    The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution.

  19. Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies.

    PubMed

    Balal, Nezah; Pinhasi, Gad A; Pinhasi, Yosef

    2016-01-01

    The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide "chirped" Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution. PMID:27223286

  20. Atmospheric and Fog Effects on Ultra-Wide Band Radar Operating at Extremely High Frequencies

    PubMed Central

    Balal, Nezah; Pinhasi, Gad A.; Pinhasi, Yosef

    2016-01-01

    The wide band at extremely high frequencies (EHF) above 30 GHz is applicable for high resolution directive radars, resolving the lack of free frequency bands within the lower part of the electromagnetic spectrum. Utilization of ultra-wideband signals in this EHF band is of interest, since it covers a relatively large spectrum, which is free of users, resulting in better resolution in both the longitudinal and transverse dimensions. Noting that frequencies in the millimeter band are subjected to high atmospheric attenuation and dispersion effects, a study of the degradation in the accuracy and resolution is presented. The fact that solid-state millimeter and sub-millimeter radiation sources are producing low power, the method of continuous-wave wideband frequency modulation becomes the natural technique for remote sensing and detection. Millimeter wave radars are used as complementary sensors for the detection of small radar cross-section objects under bad weather conditions, when small objects cannot be seen by optical cameras and infrared detectors. Theoretical analysis for the propagation of a wide “chirped” Frequency-Modulated Continuous-Wave (FMCW) radar signal in a dielectric medium is presented. It is shown that the frequency-dependent (complex) refractivity of the atmospheric medium causes distortions in the phase of the reflected signal, introducing noticeable errors in the longitudinal distance estimations, and at some frequencies may also degrade the resolution. PMID:27223286

  1. Daily lifestyles in the fog and haze weather

    PubMed Central

    Cai, Dong-Ping

    2016-01-01

    Background China is being plagued by a large-scaled lasting fog and haze, under which people have to work and live. Therefore, it matters to do what we can to minimize the adverse impact of the fog and haze on individual health on a daily basis. Methods Relative literatures on the fog and haze have been searched and reviewed. Particular attention has been paid to the literatures on the adverse impact of the fog and haze on the people’s health and on the ways minimizing this impact. Results Coming across the weather of fog and haze, appropriate measures taken can minimize its adverse impact on individuals on a daily basis. The measures included vitamin intake, water drinking, air cleaning indoors, stay-at-home, and mask wearing outdoors. These measures are simple and proven effective. Conclusions Simple and effective measures seem to be sufficient to minimizing the adverse impact of the fog and haze on the individual’s health on a daily basis. Lifestyle changes, awareness of environment protection, energy conservation, and new and clean energy use are ultimate ways to curb the air pollution and reduce the occurrence of the fog and haze. PMID:26904256

  2. Hydrophobic/Hydrophilic Cooperative Janus System for Enhancement of Fog Collection.

    PubMed

    Cao, Moyuan; Xiao, Jiasheng; Yu, Cunming; Li, Kan; Jiang, Lei

    2015-09-01

    Harvesting micro-droplets from fog is a promising method for solving global freshwater crisis. Different types of fog collectors have been extensively reported during the last decade. The improvement of fog collection can be attributed to the immediate transportation of harvested water, the effective regeneration of the fog gathering surface, etc. Through learning from the nature's strategy for water preservation, the hydrophobic/hydrophilic cooperative Janus system that achieved reinforced fog collection ability is reported here. Directional delivery of the surface water, decreased re-evaporation rate of the harvested water, and thinner boundary layer of the collecting surface contribute to the enhancement of collection efficiency. Further designed cylinder Janus collector can facilely achieve a continuous process of efficient collection, directional transportation, and spontaneous preservation of fog water. This Janus fog harvesting system should improve the understanding of micro-droplet collection system and offer ideas to solve water resource crisis.

  3. Project Fog Drops. Part 1: Investigations of warm fog properties

    NASA Technical Reports Server (NTRS)

    Pilie, R. J.; Eadie, W.; Mack, E. J.; Rogers, C.; Kocmond, W. C.

    1972-01-01

    A detailed study was made of the micrometeorological and microphysical characteristics of eleven valley fogs occurring near Elmira, New York. Observations were made of temperature, dew point, wind speed and direction, dew deposition, vertical wind velocity, and net radiative flux. In fog, visibility was continuously recorded and periodic measurements were made of liquid water content and drop-size distribution. The observations were initiated in late evening and continued until the time of fog dissipation. The vertical distribution of temperature in the lowest 300 meters and cloud nucleus concentration at several heights were measured from an aircraft before fog nucleus concentrations at several heights were measured from an aircraft before fog formation. A numerical model was developed to investigate the life cycle of radiation fogs. The model predicts the temporal evolution of the vertical distributions of temperature, water vapor, and liquid water as determined by the turbulent transfer of heat and moisture. The model includes the nocturnal cooling of the earth's surface, dew formation, fog drop sedimentation, and the absorption of infrared radiation by fog.

  4. Hierarchical Surface Architecture of Plants as an Inspiration for Biomimetic Fog Collectors.

    PubMed

    Azad, M A K; Barthlott, W; Koch, K

    2015-12-01

    Fog collectors can enable us to alleviate the water crisis in certain arid regions of the world. A continuous fog-collection cycle consisting of a persistent capture of fog droplets and their fast transport to the target is a prerequisite for developing an efficient fog collector. In regard to this topic, a biological superior design has been found in the hierarchical surface architecture of barley (Hordeum vulgare) awns. We demonstrate here the highly wettable (advancing contact angle 16° ± 2.7 and receding contact angle 9° ± 2.6) barbed (barb = conical structure) awn as a model to develop optimized fog collectors with a high fog-capturing capability, an effective water transport, and above all an efficient fog collection. We compare the fog-collection efficiency of the model sample with other plant samples naturally grown in foggy habitats that are supposed to be very efficient fog collectors. The model sample, consisting of dry hydrophilized awns (DH awns), is found to be about twice as efficient (fog-collection rate 563.7 ± 23.2 μg/cm(2) over 10 min) as any other samples investigated under controlled experimental conditions. Finally, a design based on the hierarchical surface architecture of the model sample is proposed for the development of optimized biomimetic fog collectors.

  5. Transcriptional cofactors of the FOG family interact with GATA proteins by means of multiple zinc fingers.

    PubMed Central

    Fox, A H; Liew, C; Holmes, M; Kowalski, K; Mackay, J; Crossley, M

    1999-01-01

    Friend of GATA-1 (FOG-1) is a zinc finger protein that has been shown to interact physically with the erythroid DNA-binding protein GATA-1 and modulate its transcriptional activity. Recently, two new members of the FOG family have been identified: a mammalian protein, FOG-2, that also associates with GATA-1 and other mammalian GATA factors; and U-shaped, a Drosophila protein that interacts with the Drosophila GATA protein Pannier. FOG proteins contain multiple zinc fingers and it has been shown previously that the sixth finger of FOG-1 interacts specifically with the N-finger but not the C-finger of GATA-1. Here we show that fingers 1, 5 and 9 of FOG-1 also interact with the N-finger of GATA-1 and that FOG-2 and U-shaped also contain multiple GATA-interacting fingers. We define the key contact residues and show that these residues are highly conserved in GATA-interacting fingers. We examine the effect of selectively mutating the four interacting fingers of FOG-1 and show that each contributes to FOG-1's ability to modulate GATA-1 activity. Finally, we show that FOG-1 can repress GATA-1-mediated activation and present evidence that this ability involves the recently described CtBP co-repressor proteins that recognize all known FOG proteins. PMID:10329627

  6. Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

    PubMed

    He, Xia; de los Reyes, Francis L; Leming, Michael L; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2013-09-01

    FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs). We report the first formation of FOG deposits on a concrete surface under laboratory conditions that mimic the formation of deposits in sewer systems. Results showed that calcium, the dominant metal in FOG deposits, can be released from concrete surfaces under low pH conditions and contribute to the formation process. Small amounts of additional oil to grease interceptor effluent substantially facilitated the air/water or pipe surface/water interfacial reaction between free fatty acids and calcium to produce surface FOG deposits. Tests of different fatty acids revealed that more viscous FOG deposit solids were formed on concrete surfaces, and concrete corrosion was accelerated, in the presence of unsaturated FFAs versus saturated FFAs. Based on all the data, a comprehensive model was proposed for the mechanisms of FOG deposit formation in sewer systems.

  7. Foliar uptake of fog in coastal California shrub species.

    PubMed

    Emery, Nathan C

    2016-11-01

    Understanding plant water uptake is important in ecosystems that experience periodic drought. In many Mediterranean-type climates like coastal California, plants are subject to significant drought and wildfire disturbance. During the dry summer months, coastal shrub species are often exposed to leaf wetting from overnight fog events. This study sought to determine whether foliar uptake of fog occurs in shrub species and how this uptake affects physiology and fuel condition. In a controlled greenhouse experiment, dominant California shrub species were exposed to isotopically labeled fog water and plant responses were measured. Potted plants were covered at the base to prevent root uptake. The deuterium label was detected in the leaves of four out of five species and in the stems of two of the species. While there was a minimal effect of foliar water uptake on live fuel moisture, several species had lower xylem tension and greater photosynthetic rates after overnight fog treatments, especially Salvia leucophylla. Coastal fog may provide a moisture source for many species during the summer drought, but the utilization of this water source may vary based on foliar morphology, phenology and plant water balance. From this study, it appears that drought-deciduous species (Artemisia californica and Salvia leucophylla) benefit more from overnight fog events than evergreen species (Adenostoma fasciculatum, Baccharis pilularis and Ceanothus megacarpus). This differential response to fog exposure among California shrub species may affect species distributions and physiological tolerances under future climate scenarios. PMID:27568025

  8. Efficacy of super-oxidized water fogging in environmental decontamination.

    PubMed

    Clark, J; Barrett, S P; Rogers, M; Stapleton, R

    2006-12-01

    The efficacy of decontamination using Sterilox fog was assessed against meticillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii. Ceramic tiles were inoculated with the test organisms and, once dried, were subjected to Sterilox fogging using a stationary vaporizing machine sited at a distance of 3m for 10 min and then left for a further hour. In a second experiment using the same organisms, the first 10-min fogging period was followed by a directed fogging period of 30s at a distance of 1m. Organisms were cultured from the tiles, plated on to tryptone soya agar and incubated for 48 h. Initial counts of approximately 10(9) colony-forming units/mL for both organisms were reduced approximately 10(4) fold for MRSA and 10(5.8) fold for A. baumannii when using a single fogging. The second fogging resulted in 10(6.8)-fold reductions for both organisms. Sterilox fog is safe and simple to use, and can reduce levels of nosocomial pathogens by a factor of almost 10(7). It is worthy of clinical evaluation in clinical settings to determine whether it maintains its microbicidal effects against a variety of organisms on different surfaces. PMID:17046103

  9. Foliar uptake of fog in coastal California shrub species.

    PubMed

    Emery, Nathan C

    2016-11-01

    Understanding plant water uptake is important in ecosystems that experience periodic drought. In many Mediterranean-type climates like coastal California, plants are subject to significant drought and wildfire disturbance. During the dry summer months, coastal shrub species are often exposed to leaf wetting from overnight fog events. This study sought to determine whether foliar uptake of fog occurs in shrub species and how this uptake affects physiology and fuel condition. In a controlled greenhouse experiment, dominant California shrub species were exposed to isotopically labeled fog water and plant responses were measured. Potted plants were covered at the base to prevent root uptake. The deuterium label was detected in the leaves of four out of five species and in the stems of two of the species. While there was a minimal effect of foliar water uptake on live fuel moisture, several species had lower xylem tension and greater photosynthetic rates after overnight fog treatments, especially Salvia leucophylla. Coastal fog may provide a moisture source for many species during the summer drought, but the utilization of this water source may vary based on foliar morphology, phenology and plant water balance. From this study, it appears that drought-deciduous species (Artemisia californica and Salvia leucophylla) benefit more from overnight fog events than evergreen species (Adenostoma fasciculatum, Baccharis pilularis and Ceanothus megacarpus). This differential response to fog exposure among California shrub species may affect species distributions and physiological tolerances under future climate scenarios.

  10. Experimental evaluation of fog warning system.

    PubMed

    Al-Ghamdi, Ali S

    2007-11-01

    Highway safety is a major concern to the public and to transportation professionals, so the number of crashes caused by poor visibility due to fog form an alarming statistic. Drivers respond to poor visibility conditions in different ways: some slow down; others do not. Many drivers simply follow the taillights of the vehicle ahead. Accordingly, hazardous conditions are created in which speeds are both too high for the prevailing conditions and highly variable. Findings are presented from a study of traffic crashes due to fog in the southern region of Saudi Arabia. The primary objective was to assess the effectiveness of fog detection and warning system on driver behavior regarding speed and headway. This warning system includes visibility sensors that automatically activate a variable message sign that posts an advisory speed when hazardous conditions due to fog occur. The system was installed on a 2 km section of a two-lane, rural highway. A data set of 36,013 observations from both experimental and control sections at two study sites was collected and analyzed. The data included vehicle speed, volume, and classification; time headway, time of day, and visibility distance. Although the warning system was ineffective in reducing speed variability, mean speed throughout the experimental sections was reduced by about 6.5 kph. This reduction indicates that the warning system appeared to have a positive effect on driver behavior in fog even though the observed mean speeds were still higher than the posted advisory speed. From relationships found in the literature between mean driving speed and number of crashes, a speed reduction of only 5 kph would yield a 15% decrease in the number of crashes.

  11. Coastal Fog Sustains Summer Baseflow in Northern Californian Watershed

    NASA Astrophysics Data System (ADS)

    Chung, M.; Dufour, A.; Leonardson, R.; Thompson, S. E.; Dawson, T. E.

    2015-12-01

    The Mediterranean climate of Northern California imposes significant water stress on ecosystems and water resources during the dry summer months. During summer, frequently the only water inputs occur as occult precipitation, in the form of fog and dew. In this study, we characterized the role of coastal fog, a dominant feature of Northern Californian coastal ecosystems and a widespread phenomenon associated with deep marine upwelling in west coast, arid, and Mediterranean climates worldwide. We monitored fog occurrence and intensity, throughfall following canopy interception of fog, soil moisture, streamflow, and meteorological variables, and made visual observations of the spatial extent of fog using time-lapse imagery in Upper Pilarcitos Creek Watershed (managed by San Francisco Public Utilities Commission as part of the San Francisco area water supply). We adopted a stratified sampling design that captured the watershed's elevation gradient, forest-edge versus interior locations, and different vegetation cover. The point-scale observations of throughfall inputs and transpiration suppression, estimated from the Penman equation, were upscaled using such watershed features and the observed fog "footprint" identified from the time-lapse images. When throughfall input and fog-induced transpiration suppression were incorporated into the operational watershed model, they improved estimates of summer baseflow, which remained persistently higher than could be explained without the fog effects. Fog, although providing relatively small volumetric inputs to the water balance, appears to offer significant relief of water stress throughout the terrestrial and aquatic components of the coastal Californian ecosystem and thus should be accounted for when assessing water stress availability in dry ecosystems.

  12. Alternative Agents to Prevent Fogging in Head and Neck Endoscopy

    PubMed Central

    Piromchai, Patorn; Kasemsiri, Pornthep; Thanaviratananich, Sanguansak

    2011-01-01

    Background: The essential factor for diagnosis and treatment of diseases in head and neck endoscopy is the visibility of the image. An anti-fogging agent can reduce this problem by minimizing surface tension to prevent the condensation of water in the form of small droplets on a surface. There is no report on the use of hibiscrub® or baby shampoo to reduce fogging in the literature. The objective of this study was to compare the efficacy between commercial anti-fogging agent, hibiscrub® and baby shampoo to reduce fogging for the use in head and neck endoscopy. Methods: The study was conducted at the Department of Otorhinolaryngology, Faculty of Medicine, Khon Kaen University in August 2010. Commercial anti-fogging agent, baby shampoo and hibiscrub® were applied on rigid endoscope lens before putting them into a mist generator. The images were taken at baseline, 15 seconds, 30 seconds and 1 minute. The images’ identifiers were removed before they were sent to two evaluators. A visual analogue scale (VAS) was used to rate the image quality from 0 to 10. Results: The difference in mean VAS score between anti-fogging agent, baby shampoo and hibiscrub® versus no agent were 5.46, 4.45 and 2.1 respectively. The commercial anti-fogging agent and baby shampoo had most protective benefit and performed significantly better than no agent (P = 0.05). Conclusions: Baby shampoo is an effective agent to prevent fogging during head and neck endoscopy and compares favourably with commercial anti-fogging agent. PMID:24179399

  13. Pilot Scale Advanced Fogging Demonstration

    SciTech Connect

    Demmer, Rick L.; Fox, Don T.; Archiblad, Kip E.

    2015-01-01

    Experiments in 2006 developed a useful fog solution using three different chemical constituents. Optimization of the fog recipe and use of commercially available equipment were identified as needs that had not been addressed. During 2012 development work it was noted that low concentrations of the components hampered coverage and drying in the United Kingdom’s National Nuclear Laboratory’s testing much more so than was evident in the 2006 tests. In fiscal year 2014 the Idaho National Laboratory undertook a systematic optimization of the fogging formulation and conducted a non-radioactive, pilot scale demonstration using commercially available fogging equipment. While not as sophisticated as the equipment used in earlier testing, the new approach is much less expensive and readily available for smaller scale operations. Pilot scale testing was important to validate new equipment of an appropriate scale, optimize the chemistry of the fogging solution, and to realize the conceptual approach.

  14. Fog frequency and chemical composition of fog water—a relevant contribution to atmospheric deposition in the eastern Erzgebirge, Germany

    NASA Astrophysics Data System (ADS)

    Lange, Christian A.; Matschullat, Jörg; Zimmermann, Frank; Sterzik, Göran; Wienhaus, Otto

    After successful air quality control in Central Europe has taken effect and previous problems related to atmospheric deposition supposedly solved, a new study on fog-related inputs to mountainous areas yields some surprises. The hydrological relevance of fog reaches significant levels at altitudes above 800 m a.s.l. In this study, some 25% of the water input derived from fog, equivalent to 152 fog hours per month (10% of which were sampled; 8 sites, one sampler each). The fog droplets dissolve more aerosol particles and generally contain significantly higher ion concentrations than rainwater. The related enrichment factors lie between 2.5 and 38, with 6-7 for the most relevant species. For some of the potentially noxious substances, concentrations excel the thresholds that protect, e.g., forest health. Even though fog chemistry has seen major changes as of the 1980s, and ion concentrations did decrease, the input still is relevant and contributes to a continuing strain. Interestingly, forests themselves alter the ionic composition of fog water, and a distinct trend becomes visible from open field deposition to forest interior sites.

  15. Adsorption and transport of gas-phase naphthalene on micron-size fog droplets in air.

    PubMed

    Raja, Suresh; Valsaraj, Kalliat T

    2004-02-01

    Aromatic hydrocarbon vapors adsorb to the air/water interface and are transported by wet deposition processes via fog, mist, and rain. A falling droplet apparatus was used to study the adsorption and uptake of naphthalene vapor on water droplets with diameters ranging from 14 to 200 microm. Uptake of naphthalene vapor greater than that predicted by bulk (air-water) phase equilibrium was noted for diameters less than 50 microm and was attributed to surface adsorption. The experimental values of the droplet-vapor partition constants were used to obtain the mass accommodation coefficient for naphthalene at the interface. The effect of temperature on the mass accommodation coefficientwas measured. The effects of a synthetic surfactant and a natural organic carbon surrogate (Suwanee Fulvic acid) on the uptake of naphthalene vapors on water droplets were also examined. Small droplet diameter, decreased temperature, and the presence of dissolved surface-active material in water enhanced the uptake of naphthalene into fog droplets.

  16. Evaluate and characterize mechanisms controlling transport, fate and effects of army smokes in an aerosol wind tunnel: Transport, transformations, fate and terrestrial ecological effects of fog oil obscurant smokes: Final report

    SciTech Connect

    Cataldo, D.A.; Van Voris, P.; Ligotke, M.W.; Fellows, R.J.; McVeety, B.D.; Li, Shu-mei W.; Bolton, H. Jr.; Fredrickson, J.K.

    1989-01-01

    The terrestrial transport, chemical fate, and ecological effects of fog oil (FO) smoke obscurants were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on an exposure scenario, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of fog oil smoke/obscurants is establishing the importance of environmental parameters, such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and three soil types. 29 refs., 35 figs., 32 tabs.

  17. Effects of Aridity and Fog Deposition on C3/CAM Photosynthesis and N-cycling in Welwitschia mirabilis

    NASA Astrophysics Data System (ADS)

    Soderberg, K.; Henschel, J.; Macko, S. A.

    2008-12-01

    Environmental controls on photosynthesis and N-cycling in Welwitschia mirabilis are evaluated through δ13C and δ15N analyses of leaf material from 26 individuals in the southermost population of this long-lived gymnosperm, which is endemic to the Namib Desert. The coastal Namib Desert in southwestern Africa is hyperarid in terms of rainfall, but receives up to 100 days of fog each year. This climate regime leads to interesting water relations in the Namib flora and fauna. Among many enigmatic characteristics, photosynthesis in W. mirabilis has puzzled researchers since the 1970's. Although it is predominantly a C3 plant, δ13C ranges from -17.5 to -23.5‰ in natural habitats, and can be as enriched as -14.4‰ under artificial growing conditions. Recently the CAM pathway has been confirmed, but the driver for CAM utilization has not been identified. In this study we incorporate new δ13C compositions for plants in the middle of the 100 km aridity gradient which spans the natural distribution of W. mirabilis. Initial results show an enriched δ13C signal (-20‰) in the more exposed individuals compared with those in a sandy drainage depression (-22‰). In addition, the documented correlation between rainfall and δ15N found in Kalahari C3 plants (Swap et al. 2004) is used to interpret the δ15N values in this W. mirabilis population. Initial results indicate that the fog deposition may significantly affect the nutrition of these unusual plants from the Namib Desert.

  18. Fog Water Use in Coastal California Shrub Species

    NASA Astrophysics Data System (ADS)

    Emery, N.; D'Antonio, C. M.

    2014-12-01

    Fog strongly influences plant communities along the California coast. Chaparral and California Sage Scrub are no exception. This study identified fog water use in five shrub species from the Santa Barbara region. The authors collected fog, rain and groundwater from several field sites for three years (2011-2013) to establish the source water isotopic signatures. Plant stem tissue was collected periodically throughout the summer months and water was extracted for stable isotope analysis. To account for soil evaporative fractionation, the authors collected soil samples from the field and constructed local evaporative correction lines. Preliminary mixing model analysis suggests fog water use in several shrub species while others utilized rain and groundwater during the late summer. This additional water may buffer the effects of summer drought in only some of the species that live in the shrub-dominated communities along the California coast.

  19. Identification of hydroxymethanesulfonate in fog water.

    PubMed

    Munger, J W; Tiller, C; Hoffmann, M R

    1986-01-17

    Previous studies have suggested that hydroxymethanesulfonate ion (HMSA) can be an important species in fog and cloud water. Formation of HMSA explains observed excesses of sulfur in the S(IV) state (+4 oxidation state) and formaldehyde (CH(2)O) in fogs and clouds. HMSA was determined in fog water by a novel ion-pairing chromatographic technique. Concentrations in samples collected in Bakersfield, California, within 5 kilometers of major sources of sulfur dioxide (SO(2)), were as high as 300 micromoles per liter. Total CH(2)O and S(IV) concentrations, which were measured independently, ranged from 10 to 200 and 5 to more than 300 micromoles per liter, respectively. Concentrations of CH(2)O, S(IV), and HMSA at Buttonwillow, California, which is 15 kilometers from the nearest source of SO(2), were less than those at Bakersfield but not absent. These data confirm that HMSA forms in atmospheric water droplets and can reach appreciable concentrations. HMSA represents an important source of acidity for water droplets and may also play a role in long-distance transport and transformation of SO(2).

  20. Implementation of warm-cloud processes in a source-oriented WRF/Chem model to study the effect of aerosol mixing state on fog formation in the Central Valley of California

    NASA Astrophysics Data System (ADS)

    Lee, Hsiang-He; Chen, Shu-Hua; Kleeman, Michael J.; Zhang, Hongliang; DeNero, Steven P.; Joe, David K.

    2016-07-01

    The source-oriented Weather Research and Forecasting chemistry model (SOWC) was modified to include warm cloud processes and was applied to investigate how aerosol mixing states influence fog formation and optical properties in the atmosphere. SOWC tracks a 6-D chemical variable (X, Z, Y, size bins, source types, species) through an explicit simulation of atmospheric chemistry and physics. A source-oriented cloud condensation nuclei module was implemented into the SOWC model to simulate warm clouds using the modified two-moment Purdue Lin microphysics scheme. The Goddard shortwave and long-wave radiation schemes were modified to interact with source-oriented aerosols and cloud droplets so that aerosol direct and indirect effects could be studied. The enhanced SOWC model was applied to study a fog event that occurred on 17 January 2011, in the Central Valley of California. Tule fog occurred because an atmospheric river effectively advected high moisture into the Central Valley and nighttime drainage flow brought cold air from mountains into the valley. The SOWC model produced reasonable liquid water path, spatial distribution and duration of fog events. The inclusion of aerosol-radiation interaction only slightly modified simulation results since cloud optical thickness dominated the radiation budget in fog events. The source-oriented mixture representation of particles reduced cloud droplet number relative to the internal mixture approach that artificially coats hydrophobic particles with hygroscopic components. The fraction of aerosols activating into cloud condensation nuclei (CCN) at a supersaturation of 0.5 % in the Central Valley decreased from 94 % in the internal mixture model to 80 % in the source-oriented model. This increased surface energy flux by 3-5 W m-2 and surface temperature by as much as 0.25 K in the daytime.

  1. Textbook Selection: Clearing the Fog.

    ERIC Educational Resources Information Center

    Hollabaugh, Mark

    1989-01-01

    Provides step-by-step procedures for developing an index which uses the Gunning Fog technique to evaluate the level of reading difficulty of textbooks. Cites examples, illustrations, and several warnings in the discussion. (RT)

  2. An Overview of the MATERHORN Fog Project: Observations and Predictability

    NASA Astrophysics Data System (ADS)

    Gultepe, I.; Fernando, H. J. S.; Pardyjak, E. R.; Hoch, S. W.; Silver, Z.; Creegan, E.; Leo, L. S.; Pu, Zhaoxia; De Wekker, S. F. J.; Hang, Chaoxun

    2016-09-01

    A field campaign design to study fog processes in complex terrain was a component of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. The experiment was conducted in the Wasatch Mountains during January 5-February 15, 2015. Fog and in particular, Ice fog (IF), defined as fog composed of only ice crystals, was studied during a part of the campaign, and this component of the program was dubbed MATERHORN-Fog. Ice fog often occurs in mountainous regions due do rapid cooling, such as radiative cooling, advective cooling, and cooling associated with mountain circulations (e.g., slope and valley winds). A variety of major instrument platforms were deployed, which included meteorological towers, a SODAR, a LiDAR, ceilometers, and a tethersonde profiler. In addition, in situ measurements took place at several locations surrounding Salt Lake City and Heber City. During the campaign, ice fog occurred at temperatures below -5 °C down to -13 °C and lasted for several hours until radiative heating became significant. The visibility (Vis) during ice fog events ranged from 100 m up to 10 km. At the Heber City site an array of sensors for measuring microphysical, radiative, and dynamical characteristics of IF events were deployed. Some local effects such as upslope advection were observed to affect the IF conditions. As expected during these events, ice water content (IWC) varied from 0.01 up to 0.2 g m-3, with radiative cooling fluxes as strong as 200 W m-2; turbulent heat and moisture fluxes were significantly lower during fog events than those of fog dissipation. At times, the measured ice crystal number concentration was as high as 100 cm-3 during periods of saturation with respect to ice. N i was not a constant as usually assumed in forecasting simulations, but rather changed with increasing IWC. Measurement based statistics suggested that the occurrence of IF events in the region was up to 30 % during the study period in the winter of 2015

  3. An Overview of the MATERHORN Fog Project: Observations and Predictability

    NASA Astrophysics Data System (ADS)

    Gultepe, I.; Fernando, H. J. S.; Pardyjak, E. R.; Hoch, S. W.; Silver, Z.; Creegan, E.; Leo, L. S.; Pu, Zhaoxia; De Wekker, S. F. J.; Hang, Chaoxun

    2016-08-01

    A field campaign design to study fog processes in complex terrain was a component of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. The experiment was conducted in the Wasatch Mountains during January 5-February 15, 2015. Fog and in particular, Ice fog (IF), defined as fog composed of only ice crystals, was studied during a part of the campaign, and this component of the program was dubbed MATERHORN-Fog. Ice fog often occurs in mountainous regions due do rapid cooling, such as radiative cooling, advective cooling, and cooling associated with mountain circulations (e.g., slope and valley winds). A variety of major instrument platforms were deployed, which included meteorological towers, a SODAR, a LiDAR, ceilometers, and a tethersonde profiler. In addition, in situ measurements took place at several locations surrounding Salt Lake City and Heber City. During the campaign, ice fog occurred at temperatures below -5 °C down to -13 °C and lasted for several hours until radiative heating became significant. The visibility (Vis) during ice fog events ranged from 100 m up to 10 km. At the Heber City site an array of sensors for measuring microphysical, radiative, and dynamical characteristics of IF events were deployed. Some local effects such as upslope advection were observed to affect the IF conditions. As expected during these events, ice water content (IWC) varied from 0.01 up to 0.2 g m-3, with radiative cooling fluxes as strong as 200 W m-2; turbulent heat and moisture fluxes were significantly lower during fog events than those of fog dissipation. At times, the measured ice crystal number concentration was as high as 100 cm-3 during periods of saturation with respect to ice. N i was not a constant as usually assumed in forecasting simulations, but rather changed with increasing IWC. Measurement based statistics suggested that the occurrence of IF events in the region was up to 30 % during the study period in the winter of 2015

  4. Acute toxicity of smoke screen materials to aquatic organisms, white phosphorus-felt, red phosphorus-butyl rubber and SGF No. 2 fog oil. Final report

    SciTech Connect

    Poston, T.M.; McFadden, K.M.; Bean, R.M.; Clark, M.L.; Thomas, B.L.; Killand, B.W.; Prohammer, L.A.; Kalkwarf, D.R.

    1986-04-01

    The acute toxicity of three obscurants was determined for nine freshwater organisms. The materials tested were white phosphorus-felt smoke, red phosphorus-butyl rubber (RP-BR) smoke, and smoke generator fuel (SGF) No. 2 fog oil (bulk and vaporized). The chemistry of WP-F and RP-BR smoke in water and the resulting effects on aquatic organisms are similar. Combustion of these two obscurants and their deposition in water leads to the formation of many complex oxy-phosphoric acids. Rates of hydrolysis of these complex products to ortho-phosphate were inconsistent and unpredictable over time. These products acidify water and produce toxic effects after exhausting the buffering capacity of the water. Acute 96 hr tests using Daphnia magna with neutralized and nonneutralized exposure solutions indicated that the presence of unidentified toxic component(s) acted independently of pH. At pH levels of 6.0 to 7.0, phosphorus combustion products precipitated out of solution leading to a bimodal toxic response in extended 96-hr tests with Daphnia magna. Most components of fog oil had low solubility in water. Saturation was apparent at approximately 0.1 to 0.3 mg/L total oil. Vaporization had no demonstrable effect on the chemistry or toxicity of the fog oil. Neither the bulk fog oil nor the vaporized fog oil was acutely toxic to freshwater animals at concentrations less than 10 mg/L total oil. In oil-water mixes in excess of 1.0 mg/L total oil, fog oil quickly separated and floated to the surface. The primary hazard associated with vaporized and bulk fog oil was the physical effect of oil fouling the organisms. Photolysis increased the concentration of water-soluble components of the fog oil. Acute toxicity was demonstrated in oil-water mixes (approx.10 mg/L total oil) of photolyzed bulk and vaporized fog oil. No difference in toxicity was observed between photolyzed and non-photolyzed dilutions of OWM at comparable levels of total oil.

  5. Numerical modeling of cloud chemistry effects on isocyanic acid (HNCO)

    NASA Astrophysics Data System (ADS)

    Barth, M. C.; Cochran, A. K.; Fiddler, M. N.; Roberts, J. M.; Bililign, S.

    2013-08-01

    acid (HNCO), a product of some combustion processes, can potentially have negative human health effects. While gas phase HNCO loss processes are slow, HNCO loss in the aqueous phase is much faster. The fate of HNCO is studied for different cloud chemistry conditions using a zero-dimensional chemical box model. Exposure to clouds reduces HNCO concentrations substantially under typical cumulus cloud conditions, resulting in the chemical lifetime of HNCO dropping to ~2 h compared to clear-sky conditions of several years. The effect of clouds on HNCO is strongly dependent on the pH and temperature, with more HNCO hydrolyzed at lower pH (more acidic drops) and higher temperatures. Thus, HNCO is most efficiently removed by fog or low-level stratus clouds and least efficiently removed under middle to upper troposphere conditions where cumulonimbus and pyrocumulus clouds reside. Deliquesced aerosols may be highly efficient at reducing HNCO concentrations.

  6. Effect of dilute acid on the accelerated weathering of wood

    SciTech Connect

    Williams, R.S.

    1988-02-01

    Western red cedar (Thuja plicata) specimens were soaked in acid solutions to determine the effect of acid conditions (such as low pH fog) on the weathering of wood. Daily 1-hour soaking in dilute sulfurous, sulfuric, or nitric acid (pH 2.0, 2.5, 3.0, 3.5, or 4.0) increased the rate of accelerated (xenon arc) weathering of the specimens compared to controls soaked in distilled/deionized water. Weathering was manifested as the erosion rate of the wood surface and was determined gravimetrically be fitting the weight loss over time to a linear model. This method detected significant differences between acid-treated specimens and untreated controls within 300 hours of accelerated weathering. The erosion rate was dependent on the acid type and pH. Sulfurous acid treatment caused the fastest rate of erosion, followed by sulfuric then nitric acid. None of the acids affected the erosion rate at pH 3.5 or above. Below this threshold, the rate of erosion increased as the hydrogen ion concentration increased. Sugar analysis of residues from the acids and the distilled water used to soak the wood indicated acid-dependent degradation of polysaccharides.

  7. The structures of the atmospheric boundary layer in the Yellow Sea summer fog-a comparison study with the spring fog

    NASA Astrophysics Data System (ADS)

    Zhang, S.-P.; Ren, Z.-P.; Yang, Y.-Q.; Wang, X.-G.; Xu, X.-L.

    2010-07-01

    at the fog top and the turbulence cooling, which is similar to the haar in the North Sea. The cooling effect can reach to the sea surface readily possibly due to the thin fog, the small amount of moisture, and the robust cooling at the top. (4) The turbulent layer in the summer fog is at 100 -300m high in the upper level of fog and the long wave radiation is weaker due to the inexistence of dry layer, thus the cooling effect at the fog top can hardly influence the bottom air; while in spring fog the long wave radiation cooling effect can quickly reach the bottom of the fog. These results are helpful for understanding the formation of the mechanism of the sea fogs.

  8. [Influence of fog processes on characteristics of individual particles in the urban atmosphere of Beijing].

    PubMed

    Shi, Zong-Bo; He, Ke-Bin; Chen, Yan-Ju; Yang, Fu-Mo; Zhang, Jie; Liu, Yan; Ma, Yong-Liang

    2008-03-01

    The purpose of this study is to investigate the effect of fog processes on the physical and chemical properties of aerosol particles in an urban atmosphere. Atmospheric particles were collected in the urban atmosphere of Beijing during fog and non-fog episodes. The morphology, size and elemental composition of individual particles were characterized using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDX). EDX analysis showed that elongated particles were composed of Ca-K-S or Ca-S, and most sub-round particles contained sulfur. Large amounts of elongated and sub-round particles were identified in the samples collected during fog episodes, and they were rarely detected in the samples collected during non-fog episodes. This suggests that the high relative humidity in the fogs facilitated the formation of elongated and sub-round particles. Number concentrations of particles larger than 0.2 microm were about 5 to 8 times higher during the fog episodes. In addition, a new mode around 0.4 microm appeared in number size distribution of particles during the fog episodes. These results indicate that heterogeneous reactions in the fogs could greatly change the chemical and physical properties of particles.

  9. C. elegans FOG-3/Tob can either promote or inhibit germline proliferation, depending on gene dosage and genetic context.

    PubMed

    Snow, J J; Lee, M-H; Verheyden, J; Kroll-Conner, P L; Kimble, J

    2013-05-23

    Vertebrate Tob/BTG proteins inhibit cell proliferation when overexpressed in tissue-culture cells, and they can function as tumor suppressors in mice. The single Caenorhabditis elegans Tob/BTG ortholog, FOG-3, by contrast, was identified from its loss-of-function phenotype as a regulator of sperm fate specification. Here we report that FOG-3 also regulates proliferation in the germline tissue. We first demonstrate that FOG-3 is a positive regulator of germline proliferation. Thus, fog-3 null mutants possess fewer germ cells than normal, a modest but reproducible decrease observed for each of two distinct fog-3 null alleles. A similar decrease also occurred in fog-3/+ heterozygotes, again for both fog-3 alleles, revealing a haplo-insufficient effect on proliferation. Therefore, FOG-3 normally promotes proliferation, and two copies of the fog-3 gene are required for this function. We next overexpressed FOG-3 by removal of FBF, the collective term for FBF-1 and FBF-2, two nearly identical PUF RNA-binding proteins. We find that overexpressed FOG-3 blocks proliferation in fbf-1 fbf-2 mutants; whereas germ cells stop dividing and instead differentiate in fbf-1 fbf-2 double mutants, they continue to proliferate in fog-3; fbf-1 fbf-2 triple mutants. Therefore, like its vertebrate Tob/BTG cousins, overexpressed FOG-3 is 'antiproliferative'. Indeed, some fog-3; fbf-1 fbf-2 mutants possess small tumors, suggesting that FOG-3 can act as a tumor suppressor. Finally, we show that FOG-3 and FBF work together to promote tumor formation in animals carrying oncogenic Notch mutations. A similar effect was not observed when germline tumors were induced by manipulation of other regulators; therefore, this FOG-3 tumor-promoting effect is context dependent. We conclude that FOG-3 can either promote or inhibit proliferation in a manner that is sensitive to both genetic context and gene dosage. The discovery of these FOG-3 effects on proliferation has implications for our understanding of

  10. Fog and precipitation chemistry at Delhi, North India

    NASA Astrophysics Data System (ADS)

    Ali, K.; Momin, G. A.; Tiwari, S.; Safai, P. D.; Chate, D. M.; Rao, P. S. P.

    Fog water samples were collected during three consecutive winters from the year 2000 to 2003 and their chemical compositions were studied to describe and assess the air quality in Delhi. It was found that all the samples were alkaline in nature in comparison to the neutrality of atmospheric CO 2 equilibrated pure water. Neutralization of fog acidity by cations occurs in the order of NH 4+>Ca 2+>Mg 2+. Comparison of the chemical composition of fog water and that of rain water, which were collected during the same period, indicates that nearly all the chemical constituents were higher in fog water than those in rain water except for one case of rain water which occurred on 25 December 2003. On account of much less amount of rainfall on the very occasion, all the ionic species showed very high concentration. Concentration of nitrate both in fog and temporally nearest rain water samples was nearly the same except for the rain sample of 25 December 2003, which indicates that while fog water drags only the lower tropospheric NO 3-, rain water collects an appreciable amount of NO 3- from aloft as well. Major contribution to the total lower tropospheric NH 4+ ion was made through human and animal excretion during winter season. Finally, natural source of cations like Ca 2+, K + and Mg 2+ dominated over the anthropogenically produced acidic anions. Correlation analysis between different chemical species was computed, but no concrete conclusion is drawn on the basis of this result, because the data set is statistically very small. Nevertheless, it gives an idea about the source of different ions and their chemical composition.

  11. Characterization of mineral particles in winter fog of Beijing analyzed by TEM and SEM.

    PubMed

    Li, Weijun; Shao, Longyi

    2010-02-01

    Aerosol samples were collected during winter fog and nonfog episodes in Beijing. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were applied to study morphologies, sizes, and compositions of aerosol particles. TEM observation indicates that most mineral particles collected in fog episode are scavenged in fog droplets. Number-size distributions of mineral particles collected in fog and nonfog episodes show two main peaks at the ranges of 0.1-0.3 and 1-2.5 microm, respectively. Based on their major compositions, mineral particles mainly include Si-rich, Ca-rich, and S-rich. Average S/Ca ratio of mineral particles collected in fog episode is 6.11, being eight times higher than that in nonfog episodes. Development mechanism of individual mineral particles in fog droplets is proposed. It is suggested that mineral particles with abundant alkaline components (e.g., "Ca-rich" particles) occurred in air should alleviate acidic degree of fog and contribute to complexity of fog droplets in Beijing.

  12. 33 CFR 118.130 - Fog signals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Fog signals. 118.130 Section 118... LIGHTING AND OTHER SIGNALS § 118.130 Fog signals. On waterways where visibility is frequently reduced due to fog or other causes, the District Commander may require or authorize the installation of one...

  13. 33 CFR 118.130 - Fog signals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Fog signals. 118.130 Section 118... LIGHTING AND OTHER SIGNALS § 118.130 Fog signals. On waterways where visibility is frequently reduced due to fog or other causes, the District Commander may require or authorize the installation of one...

  14. 33 CFR 118.130 - Fog signals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Fog signals. 118.130 Section 118... LIGHTING AND OTHER SIGNALS § 118.130 Fog signals. On waterways where visibility is frequently reduced due to fog or other causes, the District Commander may require or authorize the installation of one...

  15. 33 CFR 118.130 - Fog signals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Fog signals. 118.130 Section 118... LIGHTING AND OTHER SIGNALS § 118.130 Fog signals. On waterways where visibility is frequently reduced due to fog or other causes, the District Commander may require or authorize the installation of one...

  16. 33 CFR 118.130 - Fog signals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Fog signals. 118.130 Section 118... LIGHTING AND OTHER SIGNALS § 118.130 Fog signals. On waterways where visibility is frequently reduced due to fog or other causes, the District Commander may require or authorize the installation of one...

  17. Phosphorylation state of a Tob/BTG protein, FOG-3, regulates initiation and maintenance of the Caenorhabditis elegans sperm fate program.

    PubMed

    Lee, Myon-Hee; Kim, Kyung Won; Morgan, Clinton T; Morgan, Dyan E; Kimble, Judith

    2011-05-31

    FOG-3, the single Caenorhabditis elegans Tob/BTG protein, directs germ cells to adopt the sperm fate at the expense of oogenesis. Importantly, FOG-3 activity must be maintained for the continued production of sperm that is typical of the male sex. Vertebrate Tob proteins have antiproliferative activity and ERK phosphorylation of Tob proteins has been proposed to abrogate "antiproliferative" activity. Here we investigate FOG-3 phosphorylation and its effect on sperm fate specification. We found both phosphorylated and unphosphorylated forms of FOG-3 in nematodes. We then interrogated the role of FOG-3 phosphorylation in sperm fate specification. Specifically, we assayed FOG-3 transgenes for rescue of a fog-3 null mutant. Wild-type FOG-3 rescued both initiation and maintenance of sperm fate specification. A FOG-3 mutant with its four consensus ERK phosphorylation sites substituted to alanines, called FOG-3(4A), rescued partially: sperm were made transiently but not continuously in both sexes. A different FOG-3 mutant with its sites substituted to glutamates, called FOG-3(4E), had no rescuing activity on its own, but together with FOG-3(4A) rescue was complete. Thus, when FOG-3(4A) and FOG-3(4E) were both introduced into the same animals, sperm fate specification was not only initiated but also maintained, resulting in continuous spermatogenesis in males. Our findings suggest that unphosphorylated FOG-3 initiates the sperm fate program and that phosphorylated FOG-3 maintains that program for continued sperm production typical of males. We discuss implications of our results for Tob/BTG proteins in vertebrates.

  18. Diurnal temperature asymmetries and fog at Churchill, Manitoba

    NASA Astrophysics Data System (ADS)

    Gough, William A.; He, Dianze

    2015-07-01

    A variety of methods are available to calculate daily mean temperature. We explore how the difference between two commonly used methods provides insight into the local climate of Churchill, Manitoba. In particular, we found that these differences related closely to seasonal fog. A strong statistically significant correlation was found between the fog frequency (hours per day) and the diurnal temperature asymmetries of the surface temperature using the difference between the min/max and 24-h methods of daily temperature calculation. The relationship was particularly strong for winter, spring and summer. Autumn appears to experience the joint effect of fog formation and the radiative effect of snow cover. The results of this study suggests that subtle variations of diurnality of temperature, as measured in the difference of the two mean temperature methods of calculation, may be used as a proxy for fog detection in the Hudson Bay region. These results also provide a cautionary note for the spatial analysis of mean temperatures using data derived from the two different methods particularly in areas that are fog prone.

  19. Fog collectors and collection techniques

    NASA Astrophysics Data System (ADS)

    Höhler, I.; Suau, C.

    2010-07-01

    The earth sciences taught that due to the occurrence of water in three phases: gas, liquid and solid, solar energy keeps the hydrological cycle going, shaping the earth surface while regulating the climate and thus allowing smart technologies to interfere in the natural process by rerouting water and employing its yield for natural and human environments’ subsistence. This is the case of traditional fog collectors implemented by several researchers along the Atacama Desert since late ’50s such as vertical tensile mesh or macro-diamonds structures. Nevertheless, these basic prototypes require to be upgraded, mainly through new shapes, fabrics and frameworks’ types by following the principles of lightness, transformability, portability and polyvalence. The vertical canvas of conventional fog collectors contain too much stressed at each joints and as result it became vulnerable. Our study constitutes a research by design of two fog-trap devices along the Atacama Desert. Different climatic factors influence the efficiency of fog harvesting. In order to increase yield of collected fog water, we need to establish suitable placements that contain high rates of fog’s accumulation. As important as the location is also the building reliability of these collectors that will be installed. Their frames and skins have to be adjustable to the wind direction and resistant against strong winds and rust. Its fabric need to be more hydrophobic, elastic and with light colours to ease dripping/drainage and avoid ultra-violet deterioration. In addition, meshes should be well-tensed and frames well-embraced too. In doing so we have conceived two fog collectors: DropNet© (Höhler) and FogHive© (Suau). These designs explore climatic design parameters combined with the agile structural principles of Tensegrity and Geodesic widely developed by Bucky Fuller and Frei Otto. The research methods mainly consisted of literature review; fieldwork; comparative analysis of existing fog

  20. Coastal fog, climate change, and the environment

    USGS Publications Warehouse

    Torregrosa, Alicia; O'Brien, Travis A.; Faloona, Ian C.

    2014-01-01

    Coastal marine fog, a characteristic feature of climates generated at the eastern boundaries of ocean basins worldwide, evokes different feelings in those who experience it (see Figure 1). Authors and poets use fog to represent mystery, bleakness, and confusion. Film directors seek out fog to shroud scenes in eerie gloominess. Tourists visiting beaches bemoan the cool and damp conditions that create a striking contrast to the sunny warm conditions typically found less than a few kilometers inland. Airline passengers delayed by fog impatiently wait for the skies to clear. Residents get used to the Sun “rising” in midday after fog dissipates.

  1. Coastal Fog, Climate Change, and the Environment

    NASA Astrophysics Data System (ADS)

    Torregrosa, Alicia; O'Brien, Travis A.; Faloona, Ian C.

    2014-12-01

    Coastal marine fog, a characteristic feature of climates generated at the eastern boundaries of ocean basins worldwide, evokes different feelings in those who experience it (see Figure 1). Authors and poets use fog to represent mystery, bleakness, and confusion. Film directors seek out fog to shroud scenes in eerie gloominess. Tourists visiting beaches bemoan the cool and damp conditions that create a striking contrast to the sunny warm conditions typically found less than a few kilometers inland. Airline passengers delayed by fog impatiently wait for the skies to clear. Residents get used to the Sun "rising" in midday after fog dissipates.

  2. Demonstration of FOG-M (Fibre Optic Guided Missile) capabilities by means of simulation and effects of proprioceptive feedback on the control

    NASA Astrophysics Data System (ADS)

    Damen, B. J.; Vangent, R. N. H. W.; Schuffel, H.

    1988-11-01

    A simulated scenario with the Fiber Optic Guided Missile (FOG-M) with the aid of a 6 degree of freedom simulation model for investigating maneuverability and footprint areas against stationary and moving ground targets is described. The performance against moving helicopters is discussed. A simulator built for research on the FOG-M system, including man-in-the-loop control, is described. Demonstration studies indicated some problem areas, such as the manual control characteristics. A study was started concerning which type of joystick system would enhance the performance of persons with minimal experience. It was shown that providing the operator with proprioceptive feedback on the maneuverability would enhance control performance.

  3. A Case Study of the Mechanisms Modulating the Evolution of Valley Fog

    NASA Astrophysics Data System (ADS)

    Hang, C.; Nadeau, D. F.; Gultepe, I.; Hoch, S. W.; Román-Cascón, C.; Pryor, K.; Fernando, H. J. S.; Creegan, E. D.; Leo, L. S.; Silver, Z.; Pardyjak, E. R.

    2016-09-01

    We present a valley fog case study in which radiation fog is modulated by topographic effects using data obtained from a field campaign conducted in Heber Valley, Utah from January 7-February 1, 2015, as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. We use data collected on January 9, 2015 to gain insight into relationships between typical shallow radiation fog, turbulence, and gravity waves associated with the surrounding topography. A ≈ 10-30 m fog layer formed by radiative cooling was observed from 0720 to 0900 MST under cold air temperatures (≈-9 °C), near-saturated (relative humidity with respect to water ≈95 %), and calm wind (mostly <0.5 m s-1) conditions. Drainage flows were observed occasionally prior to fog formation, which modulated heat exchanges between air masses through the action of internal gravity waves and cold-air pool sloshing. The fog appeared to be triggered by cold-air advection from the south (≈200°) at 0700 MST. Quasi-periodic oscillations were observed before and during the fog event with a time period of about 15 min. These oscillations were detected in surface pressure, temperature, sensible heat flux, incoming longwave radiation, and turbulent kinetic energy measurements. We hypothesize that the quasi-periodic oscillations were caused by atmospheric gravity waves with a time period of about 10-20 min based on wavelet analysis. During the fog event, internal gravity waves led to about 1 °C fluctuations in air temperatures. After 0835 MST when net radiation became positive, fog started to dissipate due to the surface heating and heat absorption by the fog particles. Overall, this case study provides a concrete example of how fog evolution is modulated by very weak thermal circulations in mountainous terrain and illustrates the need for high density vertical and horizontal measurements to ensure that the highly spatially varying physics in complex terrain are sufficient for hypothesis

  4. An automated fog monitoring system for the Indo-Gangetic Plains based on satellite measurements

    NASA Astrophysics Data System (ADS)

    Patil, Dinesh; Chourey, Reema; Rizvi, Sarwar; Singh, Manoj; Gautam, Ritesh

    2016-05-01

    Fog is a meteorological phenomenon that causes reduction in regional visibility and affects air quality, thus leading to various societal and economic implications, especially disrupting air and rail transportation. The persistent and widespread winter fog impacts the entire the Indo-Gangetic Plains (IGP), as frequently observed in satellite imagery. The IGP is a densely populated region in south Asia, inhabiting about 1/6th of the world's population, with a strong upward pollution trend. In this study, we have used multi-spectral radiances and aerosol/cloud retrievals from Terra/Aqua MODIS data for developing an automated web-based fog monitoring system over the IGP. Using our previous and existing methodologies, and ongoing algorithm development for the detection of fog and retrieval of associated microphysical properties (e.g. fog droplet effective radius), we characterize the widespread fog detection during both daytime and nighttime. Specifically, for the night time fog detection, the algorithm employs a satellite-based bi-spectral brightness temperature difference technique between two spectral channels: MODIS band-22 (3.9μm) and band-31 (10.75μm). Further, we are extending our algorithm development to geostationary satellites, for providing continuous monitoring of the spatial-temporal variation of fog. We anticipate that the ongoing and future development of a fog monitoring system would be of assistance to air, rail and vehicular transportation management, as well as for dissemination of fog information to government agencies and general public. The outputs of fog detection algorithm and related aerosol/cloud parameters are operationally disseminated via http://fogsouthasia.com/.

  5. A Case Study of the Mechanisms Modulating the Evolution of Valley Fog

    NASA Astrophysics Data System (ADS)

    Hang, C.; Nadeau, D. F.; Gultepe, I.; Hoch, S. W.; Román-Cascón, C.; Pryor, K.; Fernando, H. J. S.; Creegan, E. D.; Leo, L. S.; Silver, Z.; Pardyjak, E. R.

    2016-08-01

    We present a valley fog case study in which radiation fog is modulated by topographic effects using data obtained from a field campaign conducted in Heber Valley, Utah from January 7-February 1, 2015, as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. We use data collected on January 9, 2015 to gain insight into relationships between typical shallow radiation fog, turbulence, and gravity waves associated with the surrounding topography. A ≈ 10-30 m fog layer formed by radiative cooling was observed from 0720 to 0900 MST under cold air temperatures (≈-9 °C), near-saturated (relative humidity with respect to water ≈95 %), and calm wind (mostly <0.5 m s-1) conditions. Drainage flows were observed occasionally prior to fog formation, which modulated heat exchanges between air masses through the action of internal gravity waves and cold-air pool sloshing. The fog appeared to be triggered by cold-air advection from the south (≈200°) at 0700 MST. Quasi-periodic oscillations were observed before and during the fog event with a time period of about 15 min. These oscillations were detected in surface pressure, temperature, sensible heat flux, incoming longwave radiation, and turbulent kinetic energy measurements. We hypothesize that the quasi-periodic oscillations were caused by atmospheric gravity waves with a time period of about 10-20 min based on wavelet analysis. During the fog event, internal gravity waves led to about 1 °C fluctuations in air temperatures. After 0835 MST when net radiation became positive, fog started to dissipate due to the surface heating and heat absorption by the fog particles. Overall, this case study provides a concrete example of how fog evolution is modulated by very weak thermal circulations in mountainous terrain and illustrates the need for high density vertical and horizontal measurements to ensure that the highly spatially varying physics in complex terrain are sufficient for hypothesis

  6. Cloud and fog interactions with coastal forests in the California Channel Islands

    NASA Astrophysics Data System (ADS)

    Still, C. J.; Baguskas, S. A.; Williams, P.; Fischer, D. T.; Carbone, M. S.; Rastogi, B.

    2015-12-01

    Coastal forests in California are frequently covered by clouds or immersed in fog in the rain-free summer. Scientists have long surmised that fog might provide critical water inputs to these forests. However, until recently, there has been little ecophysiological research to support how or why plants should prefer foggy regions; similarly, there is very little work quantifying water delivered to ecosystems by fog drip except for a few notable sites along the California coast. However, without spatial datasets of summer cloudcover and fog inundation, combined with detailed process studies, questions regarding the roles of cloud shading and fog drip in dictating plant distributions and ecosystem physiology cannot be addressed effectively. The overall objective of this project is to better understand how cloudcover and fog influence forest metabolism, growth, and distribution. Across a range of sites in California's Channel Islands National Park we measured a wide variety of ecosystem processes and properties. We then related these to cloudcover and fog immersion maps created using satellite datasets and airport and radiosonde observations. We compiled a spatially continuous dataset of summertime cloudcover frequency of the Southern California bight using satellite imagery from the NOAA geostationary GOES-11 Imager. We also created map of summertime cloudcover frequency of this area using MODIS imagery. To assess the ability of our mapping approach to predict spatial and temporal fog inundation patterns, we compared our monthly average daytime fog maps for GOES pixels corresponding to stations where fog inputs were measured with fog collectors in a Bishop pine forest. We also compared our cloudcover maps to measurements of irradiance measurements. Our results demonstrate that cloudcover and fog strongly modulate radiation, water, and carbon budgets, as well as forest distributions, in this semi-arid environment. Measurements of summertime fog drip, pine sapflow and

  7. Climatology of fog in SW-Iceland

    NASA Astrophysics Data System (ADS)

    Barranco, Aurelio; Ólafsson, Haraldur

    2016-04-01

    The climatology of fog in Keflavik Airport in Southwest-Iceland has been investigated for the latter half of the 20th Century. Fog is twice as frequent in the late night than in the afternoon, suggesting important, but not dominating, impact of the diurnal cycle. There is large interannual variability in the frequency of fog, but no clear long-term trend. However, there is a clear shift in seasonal frequency; the period 1953-1977 had relatively frequent fog in the autumn, while 1978-1998, fog is relatively frequent in the spring and summer. This indicates sensitivity of the fog to mean sea surface temperatures. An attempt is made to assess frequency of fog in climate scenarii.

  8. Fibromyalgia, Fibro Fog, and Exercise.

    PubMed

    Karper, William B; Letvak, Susan A

    2015-01-01

    Fibro fog causes serious problems for those with fibromyalgia syndrome. The mechanisms that cause it have not been well identified. Since prescription medication and other conventional medical interventions have proven less than satisfactory, and while waiting for more investigational information, research suggests that exercise might be helpful.

  9. In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China

    NASA Astrophysics Data System (ADS)

    Bi, Xinhui; Lin, Qinhao; Peng, Long; Zhang, Guohua; Wang, Xinming; Brechtel, Fred J.; Chen, Duohong; Li, Mei; Peng, Ping'an; Sheng, Guoying; Zhou, Zhen

    2016-08-01

    We use a single-particle aerosol mass spectrometer coupled with a ground-based counterflow virtual impactor to measure the chemical compositions of individual submicron fog droplet residues. This is the first report on single particle mass spectrometry measurements of fog droplet residual particles at ground level in an urban area. We show that most of the fog droplet residues were composed of elemental carbon (EC) (67.7%), followed by K-rich (19.2%) and mineral dust/metal (12.3%) particles. The predominance of EC-containing particles demonstrated that these particles could be effective fog nuclei and highlights the important influence of anthropogenic emissions on regional climate system. Compared with interstitial and ambient aerosols, nitrate was enhanced, sulfate was depressed, and ammonium- and organics-containing particles were hardly found in the fog droplet residues during fog events, suggesting that dust and metal particles containing nitrate may be preferentially activated and that ammonium and organics may not play important roles in fog formation in Guangzhou. We also present direct observational evidence that trimethylamine and hydroxymethanesulfonate are not found within fog droplet residues, although we previously observed enhanced gas-to-particle partitioning of these compounds by fog processing. Additionally, higher fraction or intensities of [K]+, [Fe]+, and [SiO3]- were found in fog droplet residues than in ambient and interstitial particles.

  10. Fog Collection and its Variability in the Andean Mountain Range of Colombia: A Possible Source for Water Supply?

    NASA Astrophysics Data System (ADS)

    Molina, J. M.

    2008-12-01

    collection was June with 5.3 l/m2/day for rainfall + fog, and 5.0 l/m2/day for fog only in dry days. Finally, it was observed that the tested fog collectors can be also effective devices to collect rainwater, mainly in dry seasons.

  11. Mesoscale numerical simulation study of warm fog dissipation by salt particles seeding

    NASA Astrophysics Data System (ADS)

    He, Hui; Guo, Xueliang; Liu, Xiang'e.; Gao, Qian; Jia, Xingcan

    2016-05-01

    Based on the dynamic framework of WRF and Morrison 2-moment explicit cloud scheme, a salt-seeding scheme was developed and used to simulate the dissipation of a warm fog event during 6-7 November 2009 in the Beijing and Tianjin area. The seeding effect and its physical mechanism were studied. The results indicate that when seeding fog with salt particles sized 80 µm and at a quantity of 6 g m-2 at the fog top, the seeding effect near the ground surface layer is negative in the beginning period, and then a positive seeding effect begins to appear at 18 min, with the best effect appearing at 21 min after seeding operation. The positive effect can last about 35 min. The microphysical mechanism of the warm fog dissipation is because of the evaporation due to the water vapor condensation on the salt particles and coalescence with salt particles. The process of fog water coalescence with salt particles contributed mostly to this warm fog dissipation. Furthermore, two series of sensitivity experiments were performed to study the seeding effect under different seeding amounts and salt particles sizes. The results show that seeding fog with salt particles sized of 80 µm can have the best seeding effect, and the seeding effect is negative when the salt particle size is less than 10 µm. For salt particles sized 80 µm, the best seeding effect, with corresponding visibility of 380 m, can be achieved when the seeding amount is 30 g m-2.

  12. Gene response in rice plants treated with continuous fog influenced by pH, was similar to that treated with biotic stress

    PubMed Central

    2014-01-01

    Background Throughout Asia, including Japan, rice plants are cultivated in a wide range of areas from lowlands to highlands and are frequently exposed to fog, including acid fog. Some physiological studies have shown that acid fog can be a stress factor for plants. We analyzed the gene expression profiles of rice plants treated with artificially prepared simulated acid fog (SiAF) or simulated neutral fog (SiNF) for 1 or 7 days. Results Microarray analysis results suggested that both the SiAF and the SiNF treatments induced the expression of genes involved in the defense and stress responses in rice plants. Induction of such genes was detected in plants treated with SiAF for 1 day, and the number of induced genes increased in plants treated with SiAF for 7 days. The genes for defense and stress responses were also induced by SiNF for 7 days, although they were not induced by SiNF for 1 day. The gene expression profiles of the SiAF-treated and the SiNF-treated plants were compared to those of plants treated with other stress factors. The comparison revealed that both SiAF and SiNF treatments have similar effects to biotic stresses and ozone stress. The genes encoding NADPH oxidase and germin, which function in apoplasts, were also induced by SiAF, SiNF and biotic stresses. Conclusions These findings suggest that both the SiAF and the SiNF treatments may result in oxidative stress through the apoplastic production of reactive oxygen species. PMID:24987489

  13. Investigating the Seasonal and Diurnal Evolution of Fog and its Effect on the Hydrometeorological Regime in the Southern Appalachian Mountains Using a Mobile Observing Platform

    NASA Astrophysics Data System (ADS)

    Wilson, A. M.; Barros, A.

    2015-12-01

    Accurate, high resolution observations of fog and low clouds in regions of complex terrain are largely unavailable, due to a lack of existing in situ observations and obstacles to satellite observations such as ground clutter. For the past year, a mobile observing platform including a ground-based passive cavity aerosol spectrometer probe (PCASP-X2), an optical disdrometer (PARSIVEL-2), a tipping bucket rain gauge, and a Vaisala weather station, collocated with a Micro Rain Radar, has been recording observations in valley locations in the inner mountain region of the Southern Appalachian Mountains (SAM). In 2014, the SAM hosted a Global Precipitation Mission field campaign (the Integrated Precipitation and Hydrology Experiment), and during this experiment the platform was also collocated at various times with a microwave radiometer, W- and X- band radars, a Pluvio weighing rain gauge, a 2D video disdrometer, among other instruments. These observations will be discussed in the context of previous findings based on observations and model results (stochastic column model and the Advanced Research Weather and Forecasting Model (WRF)). Specifically, in previous work, seeder-feeder processes have been found to govern the enhancement of light rainfall in the SAM through increased coalescence efficiency in stratiform rainfall due to the interactions with low level clouds and topography modulated fog. This presentation will focus on measurements made by the platform and collocated instruments, as well as observations made by fog collectors on ridges, with the aim of developing a process-based understanding of the characteristics of low cloud and fog through describing the diurnal cycle of microphysical and dynamical processes and properties in the region. The overarching goal is to employ observations of the formation and evolution of the "feeder" clouds and fog to further understand the magnitude and function of their contribution to the local hydrometeorological regime.

  14. Influence of fog parameters on withstand voltage of contaminated insulators

    SciTech Connect

    Naito, K.; Ito, M.; Katsukawa, H.; Kawaguchi, T.; Suzuki, Y.

    1983-03-01

    This paper describes the investigation results of fog parameters which affect the withstand voltage of contaminated insulators. As a result, the guideline is proposed on fog conditions such as density, droplet size distribution, temperature rise in the fog room, and so on, basing upon the comparison between natural and artificial fog conditions and the relation between fog condition and power-frequency withstand voltage.

  15. Quantifying the micrometorological controls on fog deposition

    NASA Astrophysics Data System (ADS)

    Farlin, J. P.; Paw U, K. T.; Underwood, J.

    2014-12-01

    Fog deposition has been shown to be a significant water input into many arid ecosystems. However, deposition of fog onto foliage depends on many factors. Previously, characterizing fog droplet size distributions was labor intensive, but currently we can characterize changes in fog droplet composition in the 2-50 μm in 2 μm intervals in real time. Evaluating how droplet size and ambient micrometeorological conditions affect deposition rates will allowing tremendous new insight into fog formation and deposition processes. Previous work has characterized fog deposition as it alters with wind speed in natural systems, but extensively testing how droplet size, wind speed, angle of interception all co-vary would be impossible in a natural setting. We utilized a wind tunnel with artificial fog generating nebulizers to simulate fog events across micrometeorological conditions. Using a weighing lysimeter, we were able to quantify the differential rates of deposition on different theoretical leaf types as droplet size and micrometeorological conditions vary. We hope to inform fog collector designs with this information to ensure we are accurately quantifying the fluxes of fog-derived water into these systems.

  16. Fog water collection measurements along the Central California Coast

    NASA Astrophysics Data System (ADS)

    Fernandez, D. M.; Hiatt, C.; Potter, C. S.

    2012-12-01

    For the past several years a number of standard fog collectors (SFC's) have been deployed at various locations in the Monterey Bay region to assess the volume and variation of Monterey area fog water deposition. SFC's contain a square meter of double thickness 50% shade Coresa mesh and are mounted with their base at a height of 2.0 meters. Each SFC is fitted with a tipping bucket rain gauge so as to accurately measure the water intercepted by each instrument. Collection of water deposition from each SFC provides a quantitative means to detect and measure the presence of ground fog and, coupled with vegetation type, to estimate the associated moisture flux to the soil. Since summer 2009, three SFC's have been deployed at locations near CSU Monterey Bay in the towns of Marina and Seaside and 3 others were deployed along an elevation gradient in the Big Sur region. The volume of water collected from each instrument is recorded at 15-minute intervals. Despite spacing of only 1-5 km between correspondent SFC's at a given location, we observe significant variations in the presence of and characteristics of coincident fog events. This presentation examines totals of fog water collected over the time period (which spans from July 2009 through 2012) as well as local gradients and diurnal and seasonal variations based upon the limited sample size. In addition, this presentation will explore the interdisciplinary connections to other regional research projects, including lizard species extinctions, assessment of the physical effects of climate change on fog, and mercury cycling.

  17. Fog spontaneously folds mosquito wings

    NASA Astrophysics Data System (ADS)

    Dickerson, Andrew K.; Liu, Xing; Zhu, Ting; Hu, David L.

    2015-02-01

    The flexibility of insect wings confers aerodynamic benefits, but can also present a hazard if exposed to fog or dew. Fog can cause water to accumulate on wings, bending them into tight taco shapes and rendering them useless for flight. In this combined experimental and theoretical study, we use high-speed video to film the spontaneous folding of isolated mosquito wings due to the evaporation of a water drop. We predict shapes of the deformed wing using two-dimensional elastica theory, considering both surface tension and Laplace pressure. We also recommend fold-resistant geometries for the wings of flapping micro-aerial vehicles. Our work reveals the mechanism of insect wing folding and provides a framework for further study of capillarity-driven folding in both natural and biomimetic systems at small scales.

  18. The cold-fog test

    SciTech Connect

    Chisholm, W.A.; Ringler, K.G.; Erven, C.C.

    1996-10-01

    The electrical performance of outdoor insulation degrades severely during combinations of factors that include surface contamination (C), ice (I), fog (F) and an ambient temperature that rises through 0 C (T{sub 0{degree}}). Failures at operating voltage on 115-kV, 230-kV and 500-kV systems occur with increasing probability under these conditions. A new CFT{sub 0{degree}} or cold-fog test method has been developed to reproduce the flashovers at all three voltage levels. Three options are identified for improving CFT{sub 0{degree}} performance: use of semi-conductive glazes, substitution of silicone for porcelain and use of silicone coatings on existing porcelain insulators.

  19. [Physical and chemical characteristics of individual mineral particles in an urban fog episode].

    PubMed

    Li, Wei-Jun; Shao, Long-Yi; Shi, Zong-Bo; Li, Jin-Juan; Yang, Shu-Shen

    2008-01-01

    Field emission scanning electron microscopy (FESEM) and scanning electron microscopy with energy dispersive X-ray detector (SEM-EDX) were used to study the four aerosol samples collected in Beijing air during the fog and non-fog episodes in winter. Size-distribution of mineral particles in fog sample displayed two major peaks at the size range of 0.1-0.3 microm and 1-2.5 microm. EDX analyses indicated that the major chemical compositions varied greatly in the individual mineral particles of the fog and non-fog episodes, especially the sulfur. A total of 9 different mineral categories were classified, namely, "Si-rich", "Ca-rich", "S-rich", "Fe-rich", "Mg-rich", "Al-rich", "Ti-rich", "K-rich" and "Cl-rich". About 55% of the "Ca-rich" in the fog samples comprised of Ca (50% +/- 1.2%)and S (37% +/- 1.6%) and about 72% of the "S-rich" comprised of S (44% +/- 1.5%) and Ca (33% +/- 2%), illustrating that particles with abundant sulfur were also enriched with abundant calcium. It is suggested that the "Ca-rich" alkali minerals could alleviate acidity of the fog water in Beijing air. The S/Ca mean ratio of mineral particles in the fog sample was 6.11, being 8 times higher than the S/Ca mean ratio of the non-fog samples (0.73). This result showed that sulfuration on the surfaces of aerosol particles was extremely severe, and that the conversion efficiency from SO2 to sulfates was relatively high.

  20. The zinc finger and C-terminal domains of MTA proteins are required for FOG-2-mediated transcriptional repression via the NuRD complex.

    PubMed

    Roche, Andrea E; Bassett, Brett J; Samant, Sadhana A; Hong, Wei; Blobel, Gerd A; Svensson, Eric C

    2008-02-01

    FOG-2 is a transcriptional co-regulator that is required for cardiac morphogenesis as mice deficient in this factor die during mid-gestation of cardiac malformations. FOG-2 interacts with GATA4 to attenuate GATA4-dependent gene expression. The first 12 amino acids of FOG-2 (the FOG Repression Motif) are necessary to mediate this repression. To determine the mechanism by which the FOG Repression Motif functions, we identified 7 polypeptides from rat cardiac nuclear extracts that co-purified with a GST-FOG-2 fusion protein. All proteins identified are members of the NuRD nucleosome remodeling complex. Using in vitro binding and co-immunoprecipitation assays, we demonstrate that Metastasis-Associated proteins (MTA)-1, 2 and 3 and Retinoblastoma binding proteins RbAp46 and RbAp48 interact with FOG-2, but not with a mutant form of FOG-2 that is unable to repress transcription. Furthermore, we define a novel domain located in the C-terminal portion of MTA-1 that mediates the FOG-2/MTA-1 interaction. We also demonstrate that knockdown of MTA protein expression dramatically impairs the ability of FOG-2 to repress GATA4 activity. Finally, we show that the zinc finger domain of MTA-1 is required for FOG-2-mediated transcriptional repression and that this domain interacts with RbAp46 and RbAp48 subunits of the NuRD complex. Together, these results demonstrate the importance of FOG-2/MTA/RbAp interactions for FOG-2-mediated transcriptional repression and further define the molecular interactions between the FOG Repression Motif and the NuRD complex.

  1. Applying GOES-derived fog frequency indices to water balance modeling for the Russian River Watershed, California

    NASA Astrophysics Data System (ADS)

    Torregrosa, A.; Flint, L. E.; Flint, A. L.; Peters, J.; Combs, C.

    2014-12-01

    Coastal fog modifies the hydrodynamic and thermodynamic properties of California watersheds with the greatest impact to ecosystem functioning during arid summer months. Lowered maximum temperatures resulting from inland penetration of marine fog are probably adequate to capture fog effects on thermal land surface characteristics however the hydrologic impact from lowered rates of evapotranspiration due to shade, fog drip, increased relative humidity, and other factors associated with fog events are more difficult to gauge. Fog products, such as those derived from National Weather Service Geostationary Operational Environmental Satellite (GOES) imagery, provide high frequency (up to 15 min) views of fog and low cloud cover and can potentially improve water balance models. Even slight improvements in water balance calculations can benefit urban water managers and agricultural irrigation. The high frequency of GOES output provides the opportunity to explore options for integrating fog frequency data into water balance models. This pilot project compares GOES-derived fog frequency intervals (6, 12 and 24 hour) to explore the most useful for water balance models and to develop model-relevant relationships between climatic and water balance variables. Seasonal diurnal thermal differences, plant ecophysiological processes, and phenology suggest that a day/night differentiation on a monthly basis may be adequate. To explore this hypothesis, we examined discharge data from stream gages and outputs from the USGS Basin Characterization Model for runoff, recharge, potential evapotranspiration, and actual evapotranspiration for the Russian River Watershed under low, medium, and high fog event conditions derived from hourly GOES imagery (1999-2009). We also differentiated fog events into daytime and nighttime versus a 24-hour compilation on a daily, monthly, and seasonal basis. Our data suggest that a daily time-step is required to adequately incorporate the hydrologic effect of

  2. Filtering and analysis on the random drift of FOG

    NASA Astrophysics Data System (ADS)

    Tian, Yun-Peng; Yang, Xiao-Jun; Guo, Yun-Zeng; Liu, Feng

    2015-10-01

    Fiber optic gyro (FOG) is an optical gyroscope which is based on the Sagnac effect and uses the optical fiber coil as light propagation channel. Gyro drift consists of two components: systemic drift and random drift. Systemic drift can be compensated by testing and calibrating. Random drift changes with time, so it becomes an important indicator to measure the precision of gyroscope, which has a great impact on the inertial navigation system. It can't be compensated by the simple method. Random drift is a main error of fiber optic gyro (FOG). The static output of FOG is a random project and it has more random noise when as the inertial navigation sensor, which will affect the measurement accuracy. It is an efficient method to reduce the random drift and improve the accuracy by modeling and compensation from the output of FOG. According to the characteristic of fiber optic gyro, the random drift model is studied. Using the time series method, the constant component of the random noise original data is extracted. After stationarity and normality tests, a normal random process is acquired. Based on this, the model is established using the recursive least squares, and then the model is applied to the normal Kalman and adaptive Kalman, finally the data is process with the filter. After experimental verification, the noise variance was reduced after filtering, and the effect is obvious.

  3. Real-time WAMI streaming target tracking in fog

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Blasch, Erik; Chen, Ning; Deng, Anna; Ling, Haibin; Chen, Genshe

    2016-05-01

    Real-time information fusion based on WAMI (Wide-Area Motion Imagery), FMV (Full Motion Video), and Text data is highly desired for many mission critical emergency or security applications. Cloud Computing has been considered promising to achieve big data integration from multi-modal sources. In many mission critical tasks, however, powerful Cloud technology cannot satisfy the tight latency tolerance as the servers are allocated far from the sensing platform, actually there is no guaranteed connection in the emergency situations. Therefore, data processing, information fusion, and decision making are required to be executed on-site (i.e., near the data collection). Fog Computing, a recently proposed extension and complement for Cloud Computing, enables computing on-site without outsourcing jobs to a remote Cloud. In this work, we have investigated the feasibility of processing streaming WAMI in the Fog for real-time, online, uninterrupted target tracking. Using a single target tracking algorithm, we studied the performance of a Fog Computing prototype. The experimental results are very encouraging that validated the effectiveness of our Fog approach to achieve real-time frame rates.

  4. Challenging Issues on fog forecast with a three-dimensional fog forecast model

    NASA Astrophysics Data System (ADS)

    Masbou, M.

    2012-12-01

    Fog has a significant impact on economical aspect (traffic management and safety) as well as on environmental issues (fresh water source for the population and the biosphere in arid region). However, reliable fog and visibility forecasts stay challenging issue. Fog is generally a small scale phenomenon which is mostly affected by local advective transport, radiation, topography, vegetation, turbulent mixing at the surface as well as its microphysical structure. In order to consider these intertwined processes, the three-dimensional fog forecast model, COSMO-FOG, with a high vertical resolution with different microphysical complexity has been developed. This model includes a microphysical parameterisation based on the one-dimensional fog forecast model. The implementation of the cloud water droplets as a new prognostic variable allows a detailed definition of the sedimentation processes and the variations in visibility. Moreover, the turbulence scheme, based on a Mellor-Yamada 2.5 order and a closure of a 2nd order has been modified to improve the model behaviour in case of a stable atmosphere structure, occurring typically during night radiative fog episodes. The potential of COSMO-FOG will be presented in some realistic fog situations (flat, bumpy and complex terrain). The fog spatial extension will be compared with MSG satellite products for fog and low cloud. The interplays between dynamical, thermodynamical patterns and the soil-atmosphere interactions will be presented.

  5. Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets

    NASA Astrophysics Data System (ADS)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.

    2013-09-01

    Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α,β-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

  6. Inexpensive anti-fog coating for windows

    NASA Technical Reports Server (NTRS)

    Carmin, D. L., Jr.; Morrison, H. D.

    1971-01-01

    Coating applications include anti-fog protection for deep-sea diving equipment, fire protection helmets, and windows of vehicles used in hazardous environments. Basic coating composition includes liquid detergent, deionized water, and oxygen compatible fire-resistant oil. Composition prevents visor fogging under maximum metabolic load for 5 hours and longer.

  7. Fog processing of polycyclic aromatic hydrocarbons (PAH)

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Khadapkar, K.; Ehrenhauser, F. S.; Hutchings, J. W.; Wornat, M. J.; Valsaraj, K. T.; Herckes, P.

    2010-07-01

    Polyaromatic hydrocarbons (PAHs) are a class of organic species of concern for environmental and human health. The present work will present initial finding of a comprehensive study on the fate of PAHs in multiphase fog/cloud systems and across consecutive fog/smog cycles. Field observations were conducted in Fresno, CA in Winter 2010. Simultaneous measurements of gas phase, aerosol and fog PAH allowed to gain insights on the partitioning of PAH in a multiphase fog system. Partitioning results as well as temporal evolution of PAH concentrations across different phases will be discussed. Select known degradation products (oxy-PAH) from the processing of PAHs were also analyzed in the fog systems, although frequently their concentrations were close to or below detection limits, even in the polluted urban study setting. The field observations are complemented by laboratory investigations on the reactivity of PAH in fog systems, both heterogeneously and in the aqueous phase. Heterogeneously a novel reactor design is being tested to simulate fog systems and allow for repeat fog/smog cycles. A separate series of measurements investigated the processing of PAH in the aqueous phase in a solar simulator set-up.

  8. Fog Machines, Vapors, and Phase Diagrams

    ERIC Educational Resources Information Center

    Vitz, Ed

    2008-01-01

    A series of demonstrations is described that elucidate the operation of commercial fog machines by using common laboratory equipment and supplies. The formation of fogs, or "mixing clouds", is discussed in terms of the phase diagram for water and other chemical principles. The demonstrations can be adapted for presentation suitable for elementary…

  9. Effusion of hydrophobic organic compounds (HOCs) from fog droplets

    SciTech Connect

    Lee, W.M.; Tsay, C.

    1998-12-31

    In this study, the effects of surface-active substances, pH and salt on the effusion of HOCs from droplets were investigated. An HOCs-effusion reactor was established for experiments. N-octane was used for the HOCs and Sodium Dodecyl Sulfate (SDS) was selected as the surface-active substance. A correction factor to mass exchange constant, defined as the deviation of exchange constant of n-octane in fog phase from that in planar aqueous phase was used to quantify the effects of surface-active substance, pH, and salt concentration on the effusion rate of HOCs from fog droplets by a modified double-layer diffusion model. The results showed that surface-active substances, SDS cab decrease the effusion rate of n-octane from fog droplets by about 40%--62% and the values of were in the range of 0.382 to 0.609. The salt, sodium chloride, at the concentration of 1.00 {times} 10{sup {minus}3} [M] can further decrease the mass transfer rate of n-octane from fog droplets because the values changed from 0.590 to 0.368, so that the effusion rate was further decrease by salt. When pH values were between 5.60 and 2.00, values varied from 0.609 to 0.367 at SDS concentration of 1.00 x 10{sup 3}[M]. This indicated that the effusion rate of HOCs from fog droplets decreased with decreasing pH value.

  10. Fog Studies for University Students and High School Teachers

    NASA Astrophysics Data System (ADS)

    Witiw, M.; Ladochy, S.

    2010-07-01

    Over the past few years, fog studies have been introduced as part of courses in Earth system science for both university students and high school teachers at Seattle Pacific University. In the undergraduate course, about three hours are devoted to the study of fog starting with a discussion on sustainable water systems. This is followed by presentations on types of fog, the role of fog in the biosphere, biogeochemical cycles and fog, human influences on fog and fog intensity, and remote sensing of fog. We end with a description of fog collection. Fog education efforts increased for students when our campus was able to obtain fog collecting equipment from Richard Jagels at the University of Maine. The equipment included active and passive fog collectors as well as infrared-beam fog detectors. Two graduating students took on fog collection as their senior project. After setting up the newly acquired equipment, the students designed a fog collection project for the University’s Whidby Island location on Puget Sound, an area that experiences frequent advection fog. They built a passive fog detector and determined where to place it on the Island. Future projects planned include implementing a water system based upon fog collection on Whidby Island. We have also implemented a new module on fog for the Earth System Science Education Alliance (ESSEA) - The Camanchaca: Fog in the Earth System (available at: http://essea.strategies.org/module.php?module_id=54). Aspects of fog in the Earth system are discussed and participants are led to see the important role fog has throughout the Earth system. This module was successfully piloted as part of an Earth system science course for teachers offered in June-July, 2009.

  11. On the fog variability over south Asia

    NASA Astrophysics Data System (ADS)

    Syed, F. S.; Körnich, H.; Tjernström, M.

    2012-12-01

    An increasing trend in fog frequencies over south Asia during winter in the last few decades has resulted in large economical losses and has caused substantial difficulties in the daily lives of people. In order to better understand the fog phenomenon, we investigated the climatology, inter-annual variability and trends in the fog occurrence from 1976 to 2010 using observational data from 82 stations, well distributed over India and Pakistan. Fog blankets large area from Pakistan to Bangladesh across north India from west to east running almost parallel to south of the Himalayas. An EOF analysis revealed that the fog variability over the whole region is coupled and therefore must be governed by some large scale phenomenon on the inter-annual time scale. Significant positive trends were found in the fog frequency but this increase is not gradual, as with the humidity, but comprises of two distinct regimes shifts, in 1990 and 1998, with respect to both mean and variance. The fog is also detected in ERA-Interim 3 hourly, surface and model level forecast data when using the concept of "cross-over temperature" combined with boundary layer stability. This fog index is able to reproduce the regime shift around 1998 and shows that the method can be applied to analyze fog over south Asia. The inter-annual variability seems to be associated with the wave train originating from the North Atlantic in the upper troposphere that when causing higher pressure over the region results in an increased boundary layer stability and surface-near relative humidity. The trend and shifts in the fog occurrence seems to be associated with the gradual increasing trend in relative humidity from 1990 onwards.

  12. On the fog variability over south Asia

    NASA Astrophysics Data System (ADS)

    Syed, F. S.; Körnich, H.; Tjernström, M.

    2012-04-01

    An increasing trend in fog frequencies over south Asia during winter in the last few decades has resulted in large economical losses and has caused substantial difficulties in the daily lives of people. In order to better understand the fog phenomenon, we investigated the climatology, inter-annual variability and trends in the fog occurrence from 1976 to 2010 using observational data from 82 stations, well distributed over India and Pakistan. Fog blankets large area from Pakistan to Bangladesh across north India from west to east running almost parallel to south of the Himalayas. An EOF analysis revealed that the fog variability over the whole region is coupled and must therefore be governed by some large scale phenomenon on the inter-annual time scale. Significant trends were found in the fog frequencies and this increase is not gradual, as seen in the humidity, but shows two distinct regimes shifts in 1990 and 1998 with respect to both mean and variance. The fog is also detected in ERA-Interim 3 hourly, surface and model level forecast data when using the concept of "cross-over temperature" combined with boundary layer stability. This detected fog index is able to reproduce the regime shift around 1998 and shows that the method can be applied to detect fog over south Asia. The inter-annual variability seems to be associated with the wave train originating from north Atlantic in the upper atmosphere that causes higher pressure over the region,resulting in increased boundary layer stability and surface-near relative humidity. The trend and shifts in the fog occurrence seems to be associated with the gradual increasing trend in relative humidity from 1990 onwards.

  13. Characterization of multilayer anti-fog coatings.

    PubMed

    Chevallier, Pascale; Turgeon, Stéphane; Sarra-Bournet, Christian; Turcotte, Raphaël; Laroche, Gaétan

    2011-03-01

    Fog formation on transparent substrates constitutes a major challenge in several optical applications requiring excellent light transmission characteristics. Anti-fog coatings are hydrophilic, enabling water to spread uniformly on the surface rather than form dispersed droplets. Despite the development of several anti-fog coating strategies, the long-term stability, adherence to the underlying substrate, and resistance to cleaning procedures are not yet optimal. We report on a polymer-based anti-fog coating covalently grafted onto glass surfaces by means of a multistep process. Glass substrates were first activated by plasma functionalization to provide amino groups on the surface, resulting in the subsequent covalent bonding of the polymeric layers. The anti-fog coating was then created by the successive spin coating of (poly(ethylene-maleic anhydride) (PEMA) and poly(vinyl alcohol) (PVA) layers. PEMA acted as an interface by covalently reacting with both the glass surface amino functionalities and the PVA hydroxyl groups, while PVA added the necessary surface hydrophilicity to provide anti-fog properties. Each step of the procedure was monitored by XPS, which confirmed the successful grafting of the coating. Coating thickness was evaluated by profilometry, nanoindentation, and UV visible light transmission. The hydrophilic nature of the anti-fog coating was assessed by water contact angle (CA), and its anti-fog efficiency was determined visually and tested quantitatively for the first time using an ASTM standard protocol. Results show that the PEMA/PVA coating not only delayed the initial period required for fog formation but also decreased the rate of light transmission decay. Finally, following a 24 hour immersion in water, these PEMA/PVA coatings remained stable and preserved their anti-fog properties.

  14. Fog-Influenced Submicron Aerosol Number Size Distributions

    NASA Astrophysics Data System (ADS)

    Zikova, N.; Zdimal, V.

    2013-12-01

    The aim of this work is to evaluate the influence of fog on aerosol particle number size distributions (PNSD) in submicron range. Thus, five-year continuous time series of the SMPS (Scanning Mobility Particle Sizer) data giving information on PNSD in five minute time step were compared with detailed meteorological records from the professional meteorological station Kosetice in the Czech Republic. The comparison included total number concentration and PNSD in size ranges between 10 and 800 nm. The meteorological records consist from the exact times of starts and ends of individual meteorological phenomena (with one minute precision). The records longer than 90 minutes were considered, and corresponding SMPS spectra were evaluated. Evaluation of total number distributions showed considerably lower concentration during fog periods compared to the period when no meteorological phenomenon was recorded. It was even lower than average concentration during presence of hydrometeors (not only fog, but rain, drizzle, snow etc. as well). Typical PNSD computed from all the data recorded in the five years is in Figure 1. Not only median and 1st and 3rd quartiles are depicted, but also 5th and 95th percentiles are plotted, to see the variability of the concentrations in individual size bins. The most prevailing feature is the accumulation mode, which seems to be least influenced by the fog presence. On the contrary, the smallest aerosol particles (diameter under 40 nm) are effectively removed, as well as the largest particles (diameter over 500 nm). Acknowledgements: This work was supported by the projects GAUK 62213 and SVV-2013-267308. Figure 1. 5th, 25th, 50th, 75th and 95th percentile of aerosol particle number size distributions recorded during fog events.

  15. Factors that influence properties of FOG deposits and their formation in sewer collection systems.

    PubMed

    Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2014-02-01

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system.

  16. Factors that influence properties of FOG deposits and their formation in sewer collection systems.

    PubMed

    Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2014-02-01

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system. PMID:24317022

  17. Fog composition at Baengnyeong Island in the eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    NASA Astrophysics Data System (ADS)

    Boris, A. J.; Lee, T.; Park, T.; Choi, J.; Seo, S. J.; Collett, J. L., Jr.

    2016-01-01

    Samples of fog water were collected at Baengnyeong Island (BYI) in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 µM), NO3- (1260 µM), SO4-2 (730 µM), and Na+ (551 µM), with substantial contributions from other species consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h) showed that high relative humidity ( > 80 %) was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, southeastern China, northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV) concentrations were measured (mean of 2.36 µM) in contrast to SO4-2 and in contrast to fog/cloud S(IV) concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low-molecular-mass organic acids were major contributors to total organic carbon (TOC; 36-69 %), comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP) reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and fogs.

  18. Fog composition at Baengnyeong Island in the Eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    NASA Astrophysics Data System (ADS)

    Boris, A. J.; Lee, T.; Park, T.; Choi, J.; Seo, S.; Collett, J. L., Jr.

    2015-09-01

    Samples of fog water were collected at Baengnyeong Island (BYI) in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 μM), NO3- (1260 μM), SO4-2 (730 μM), and Na+ (551 μM), with substantial contributions from other ions consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h) showed that high relative humidity (> 80 %) was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, Northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV) concentrations were measured (mean of 2.36 μM) in contrast to SO4-2 and in contrast to fog/cloud S(IV) concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low molecular mass organic acids were major contributors to total organic carbon (TOC; 36-69 %), comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids, but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP) reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and fogs.

  19. Revisiting the fog bottle experiment

    NASA Astrophysics Data System (ADS)

    Kamcharean, C.; Khanchong, C.; Wattanakasiwich, P.

    2016-11-01

    In this article we propose an irreversible adiabatic expansion model, modified from previous work, to explain the fog bottle experiment. Our model divides the phenomenon into five thermodynamic states, and we include in our calculation irreversible work pushing a stopper out of the bottle and heat gain from the condensation of saturated vapour. In the experiment, thermodynamic variables including pressure and temperature as functions of time were measured. The work done in pushing the stopper out was measured and the condensation heat was determined using the Clausius–Clapeyron equation to determine saturated vapour pressure. As a result, fog formation was explained through a phase diagram of water showing the saturated vapour pressure during irreversible adiabatic expansion. Also, state variables (P, V and T) and the entropy change of the real process were compared with the reversible and irreversible adiabatic expansion and our modified process. Using a P–T diagram, we show that the amount of reversible work is always higher than the amount of irreversible work, due to dissipative work. According to our modified model, the dissipative work and the heat transferred from condensation cause irreversibility or {{Δ }}{S}{{t}{{o}}{{t}}{{a}}{{l}}}\\gt 0.

  20. Therapy in a fog.

    PubMed

    Shephard, R J

    1971-04-01

    Dr. Shephard reviews the current status of aerosol therapy with particular reference to the treatment of cystic fibrosis. The water deficit of the atmosphere, the composition and size of the aerosol particles and the mode of administration are shown to be important variables. The majority of aerosol generators create polydisperse clouds with a high mass median diameter (4-5 microns) and as much as 90 percent of the aerosol is deposited in the mouth and throat; in consequence, the volume of nebulized fluid reaching the bronchi is not more than 2-3 ml./hour.The importance of the dual blood supply to the lung is emphasized; if pharmacologically active aerosols are absorbed into the bronchial circulation, they may circulate as a "slug" and produce dangerous toxic effects. The influence of airflow turbulence upon the impaction of large particles, and a dead space upon the retention of small particles is considered. The main potential value of aerosol therapy lies in the application of high concentrations of active drugs to poorly vascularized areas of the lung. In order to realize this potential, better aerosol generators must be developed and much more must be discovered about the behavior of small particles in the airstream.

  1. Acute renal failure, neuropathy, and myopathy after ingestion of dipropylene glycol fog solution.

    PubMed

    LoVecchio, Frank; Nourani, Cameron; Watts, D J; Wallance, K L; Wax, P M

    2008-06-01

    Dipropylene glycol is used in several industrial products including cosmetics, emulsifiers, solvents, and as a fog solution for dance club special effects. Animal studies have suggested that dipropylene glycol has minimal toxicity. We report a case of a 32-year-old man who ingested more than 500 mL of dipropylene glycol-containing Fantasia fog solution (High Energy Lighting, Houston, TX) and subsequently developed acute renal failure, polyneuropathy, and myopathy.

  2. Fog chemistry at three sites in Norway

    NASA Astrophysics Data System (ADS)

    Wang, Youliang; Zhang, Jinwei; Marcotte, Aurelie R.; Karl, Matthias; Dye, Christian; Herckes, Pierre

    2015-01-01

    Fog composition was investigated at three sites in Norway, one in suburban Oslo and two coastal sites in the area of the Mongstad refinery. Overall fog frequency during the study periods was low. Fog pH was around 5 with slightly lower values at Hakadal, the suburban site, compared to the coastal sites, which were slightly above 5. Major ions at the coastal sites were sodium and chloride consistent with the marine environment. The ion chemistry at the suburban site was dominated by ammonium, sulfate and nitrate, consistent with fogs in anthropogenically impacted environments. Overall concentrations of major ions were very low, orders of magnitude lower than those in polluted urban fogs. Organic matter concentrations were also low (< 3 mgC/L) consistent with limited anthropogenic impact and little biogenic activity in the winter months. Selected amine concentrations were determined and ranged from nanomolar concentrations for ethylamines to several hundred nanomolar concentrations for dimethylamine, the most abundant amine investigated. While N-nitrosodimehylamine was detected in fog, the concentrations were very low in the fogs.

  3. Insights into association of the NuRD complex with FOG-1 from the crystal structure of an RbAp48·FOG-1 complex.

    PubMed

    Lejon, Sara; Thong, Sock Yue; Murthy, Andal; AlQarni, Saad; Murzina, Natalia V; Blobel, Gerd A; Laue, Ernest D; Mackay, Joel P

    2011-01-14

    Chromatin-modifying complexes such as the NuRD complex are recruited to particular genomic sites by gene-specific nuclear factors. Overall, however, little is known about the molecular basis for these interactions. Here, we present the 1.9 Å resolution crystal structure of the NuRD subunit RbAp48 bound to the 15 N-terminal amino acids of the GATA-1 cofactor FOG-1. The FOG-1 peptide contacts a negatively charged binding pocket on top of the RbAp48 β-propeller that is distinct from the binding surface used by RpAp48 to contact histone H4. We further show that RbAp48 interacts with the NuRD subunit MTA-1 via a surface that is distinct from its FOG-binding pocket, providing a first glimpse into the way in which NuRD assembly facilitates interactions with cofactors. Our RbAp48·FOG-1 structure provides insight into the molecular determinants of FOG-1-dependent association with the NuRD complex and into the links between transcription regulation and nucleosome remodeling.

  4. Three dimensional fog forecasting in complex terrain

    NASA Astrophysics Data System (ADS)

    Mueller, M.; Masbou, M.; Bott, A.

    2010-07-01

    Fog in complex terrain shows large temporal and spatial variations that can only be simulated with a three-dimensional model, but more modifications than increasing the resolution are needed. For a better representation of fog we present a second moment cloud water scheme with a parametrization of the Köhler theory which is combined with the mixed phase Ferrier microphysics scheme. The more detailed microphysics produce many differences to the first moment Ferrier scheme and are responsible for reproducing the typically low liquid water content of fog. With explicitly predicted droplet number concentrations, sedimentation of cloud water can be modeled without a prescribed fall speed, which mainly affects the vertical distribution of cloud water and the end of the fogs life cycle. The complex topography of the Swiss Alps and its surroundings are used for model testing. As the focus is on the models ability to forecast the spatial distribution of fog, cloud patterns derived from high resolution MSG satellite data, rather than few point observations from ground stations are used. In a continous five day period of anticyclonic conditions, the satellite observed fog patterns showed large day to day variations with almost no fog to large areas of fog. This variability was very well simulated in the three-dimensional fog forecast. The simulations also demonstrate the need for high horizontal resolutions between 1 and 3 km. For model initialization the complex topography is actually a simplifying factor, as cold air flow and pooling are dominating the more uncertain processes of evapotranspiration or errors in the soil moisture field.

  5. Fog droplet distribution functions for lidar.

    PubMed

    Mallow, J V

    1982-04-15

    The interpretation of lidar data on fog has been limited by two obstacles: approximations in the form of the Mie scattering cross sections for water droplets, and droplet size distribution functions whose relationship to the experiment has not been clear. This paper develops a method for generating distribution functions from experimental data. These functions are then used with newly available Mie cross sections to obtain backscattering and extinction coefficients for singly scattered ruby laser pulses in fog. The results show what experimental lidar accuracies are needed to uniquely determine fog droplet size distribution.

  6. Fog droplet distribution functions for lidar

    SciTech Connect

    Mallow, J.V.

    1982-04-15

    The interpretation of lidar data on fog has been limited by two obstacles: approximations in the form of the Mie scattering cross sections for water droplets, and droplet size distribution functions whose relationship to the experiment has not been clear. This paper develops a method for generating distribution functions from experimental data. These functions are then used with newly available Mie cross sections to obtain backscattering and extinction coefficients for singly scattered ruby laser pulses in fog. The results show what experimental lidar accuracies are needed to uniquely determine fog droplet size distribution.

  7. Evaluation of hand applied naled thermal fog for Wyeomyia control.

    PubMed

    Curtis, G A; Carlson, D B

    1990-09-01

    Tests on the effect of hand applied naled thermal fog, both as a single treatment on one day/week and a single treatment on 3 successive days, did not control Wyeomyia vanduzeei and Wy. mitchellii. Five-min landing/biting counts in a native oak/palm woodland demonstrated that single applications produced an average landing rate decrease of 13%. Treatments 3 days in succession did not suppress the landing rate. PMID:1977876

  8. Development of Satellite-based Climatology of Low-level Cloud and Fog in Mountain Terrain

    NASA Astrophysics Data System (ADS)

    Duan, Y.; Barros, A. P.

    2014-12-01

    The presence of orographic clouds and fog has major environmental and economic implications that the potential shift in the space-time distribution can effectively redistribute freshwater resources and threaten the sustainability of the ecology, geomorphology and hydrology of mountainous regions and adjacent basins. This includes the Southern Appalachian Mountains, which rely closely on the moisture input from fog, cap clouds and light rainfall, as well as cloud forests in the Andes with frequent occurrence of dense fog. However, the applicability of fog forecasting models becomes limited in regions of complex terrain. The motivation of this project is to develop a satellite-based hydroclimatology and physical parameterization of orographic low-level clouds and fog regimes in the Southern Appalachians using a general methodology that can be applied to mountainous regions elsewhere. An algorithm for the detection and extraction of stratus clouds and fog was developed using changes in vertical gradients of CPR reflectivity and liquid water products from almost 5-years of CLOUDSAT and SRTM terrain data. This population of low-level clouds and fog will be analyzed with GOES infrared and visible imagery, MODIS and CALIPSO products, and with airport cloud height and visibility records to expand the spatial coverage beyond narrow satellite sensor swaths. The climatology will be further developed through integration with results from WRF simulations for selected periods since the bulk of the PMM network has been in place (2008-present) to aid in defining meteorological and time-of-day constraints in the interpretation of simulated satellite radar reflectivity profiles. The overarching goal is to infer a representation of the diurnal cycle, seasonal and inter-annual variations of the vertical distribution of LWC and hydrometeors in orographic clouds and fog that vary spatially with landform toward developing a more general parameterization of seeder-feeder interactions in

  9. Utility fog: A universal physical substance

    NASA Technical Reports Server (NTRS)

    Hall, J. Storrs

    1993-01-01

    Active, polymorphic material ('Utility Fog') can be designed as a conglomeration of 100-micron robotic cells ('foglets'). Such robots could be built with the techniques of molecular nanotechnology. Controllers with processing capabilities of 1000 MIPS per cubic micron, and electric motors with power densities of one milliwatt per cubic micron are assumed. Utility Fog should be capable of simulating most everyday materials, dynamically changing its form and properties, and forms a substrate for an integrated virtual reality and telerobotics.

  10. The optical properties and chemical composition of Po Valley fog water

    NASA Astrophysics Data System (ADS)

    Jahl, L.; Hawkins, L. N.; Gilardoni, S.

    2013-12-01

    The chemical composition and solar radiation absorption properties of fog water are important because of the effects these properties can have on the climate. Fog samples contain compounds that may absorb light, and this radiative forcing may be significant. The Po Valley, located between the Apennine and Alps mountain ranges in Italy, has a high occurrence of fog events, which can be up to 30% of the time in the winter season. Absorption spectra of fog water samples from San Pietro Capofiume, Italy were taken in a Liquid Waveguide Capillary Cell with a UV-visible spectrophotometer. Spectra were fitted and absorptions at different wavelengths were correlated to the organic carbon and organic nitrogen concentrations of the samples. Ion chromatography was also used to obtain the concentrations of several ions such as nitrite, nitrate, sulfate, acetate, ammonium, and various amines. A correlation was found between absorbance and organic carbon content, as well as between absorbance at less than 300 nm wavelengths and organic nitrogen content. Characteristic absorptivities at 365 nm were calculated from Beer's law with regard to the organic carbon content and revealed similar results to those calculated from Los Angeles fog water samples earlier this year. The absorption angstrom exponents of the samples imply that the likely source of the optically active species is from biomass burning, and this will later be confirmed by a tracer analysis. High organic nitrogen : organic carbon ratios in all samples suggest that compounds containing nitrogen have a large contribution to the light absorbing properties of fog water.

  11. Centrifugation-Assisted Fog-Collecting Abilities of Metal-Foam Structures with Different Surface Wettabilities.

    PubMed

    Ji, Keju; Zhang, Jun; Chen, Jia; Meng, Guiyun; Ding, Yafei; Dai, Zhendong

    2016-04-20

    The collection of water from fog is a simple and sustainable means of obtaining freshwater for human and animal consumption. Herein, we address the use of metal foam in fog collection and present a novel fog-collecting device fabricated from copper foam. This device, which can also be used in other liquid-gas separation applications, is a 3D extension of biologically inspired 1D and 2D materials. The network structure of the 3D material effectively increased the contact area and interaction time of the skeleton structure and fog compared to those of traditional 2D fog-collecting materials. The main aspects investigated in this study were the influences of the inertial centrifugal force generated by rotating the metal-foam samples and the use of samples with different surface wettabilities on the fog-collecting performance. Superhydrophilic and superhydrophobic samples were found to have higher collection efficiencies at low and high rotational speeds, respectively, and a maximum efficiency of 86% was achieved for superhydrophobic copper foam (20 pores per inch) rotated at 1500 rpm. PMID:27065476

  12. Centrifugation-Assisted Fog-Collecting Abilities of Metal-Foam Structures with Different Surface Wettabilities.

    PubMed

    Ji, Keju; Zhang, Jun; Chen, Jia; Meng, Guiyun; Ding, Yafei; Dai, Zhendong

    2016-04-20

    The collection of water from fog is a simple and sustainable means of obtaining freshwater for human and animal consumption. Herein, we address the use of metal foam in fog collection and present a novel fog-collecting device fabricated from copper foam. This device, which can also be used in other liquid-gas separation applications, is a 3D extension of biologically inspired 1D and 2D materials. The network structure of the 3D material effectively increased the contact area and interaction time of the skeleton structure and fog compared to those of traditional 2D fog-collecting materials. The main aspects investigated in this study were the influences of the inertial centrifugal force generated by rotating the metal-foam samples and the use of samples with different surface wettabilities on the fog-collecting performance. Superhydrophilic and superhydrophobic samples were found to have higher collection efficiencies at low and high rotational speeds, respectively, and a maximum efficiency of 86% was achieved for superhydrophobic copper foam (20 pores per inch) rotated at 1500 rpm.

  13. Fog and precipitation chemistry at a mid-land forest in central Taiwan.

    PubMed

    Liang, Yang-Ling; Lin, Teng-Chiu; Hwong, Jeen-Liang; Lin, Neng-Huei; Wang, Chiao-Ping

    2009-01-01

    We analyzed fog and bulk precipitation chemistry at a cloud forest in central Taiwan where mountain agriculture activities are highest. There were 320 foggy days (visibility <1000 m) recorded between April 2005 and March 2006. Fog was most frequent between April 2005 and July 2005 and in March 2006 (153/153 d) and least frequent in January 2006 (21/31 d). The total fog duration was 2415 h, representing 28% of the sampling period. Compared with bulk precipitation, fog was disproportionally enriched in NO(3)(-) and SO(4)(2-) relative to K(+), Ca(2+), Mg(2+), and NH(4)(+), resulting in higher a content of nitric acid and sulfuric acid than weak acids or neutral salts and, therefore, higher acidity (median pH, 4.9) in fog than in bulk precipitation (median and mean pH, 5.5). The very high input of NH(4)(+) (47 kg N ha(-1) yr(-1)) through bulk precipitation suggests that the use of fertilizer (ammonium sulfate and animal manure) associated with mountain agriculture has a major impact on atmospheric deposition at the surrounding forest ecosystems. The input of inorganic N reached 125 kg N ha(-1) yr(-1) and likely exceeded the biological demand of the forest ecosystem. Sulfate is the most abundant anion in fog at Chi-tou and in precipitation at various forests throughout Taiwan, suggesting that the emission and transport of large quantities of SO(2,) the precursor of SO(4)(2-), is an island-wide environmental issue.

  14. Measuring mercury in coastal fog water

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-04-01

    Mercury, a heavy metal neurotoxin, accumulates in sea life, in some cases reaching levels that make seafood unsafe for humans to eat. How mercury gets into aquatic organisms is debated, but part of the pathway could include mercury carried in precipitation, including rain, snow, and fog. The contribution of mercury in fog water in particular is not well known, especially in foggy coastal areas such as coastal California. To learn more, Weiss-Penzias et al. measured total mercury and monomethyl mercury concentrations in fog water and rainwater samples taken from four locations around Monterey Bay, California, during spring and summer 2011. They found that the mean monomethyl mercury concentrations in their fog water samples were about 34 times higher than the mean concentrations in their rainwater samples. Therefore, the authors believe that fog is an important, previously unrecognized source of mercury to coastal ecosystems. They also explored potential sources of mercury, finding that biotically formed monomethyl mercury from oceanic upwelling may contribute to monomethyl mercury in fog. (Geophysical Research Letters, doi:10.1029/2011GL050324, 2012)

  15. Persistent and Widespread Winter Haze & Fog over the Indo-Gangetic Plains: A climatological perspective from satellite observations

    NASA Astrophysics Data System (ADS)

    Gautam, R.

    2014-12-01

    Each year during winter season (December-January), dense fog engulfs the Indo-Gangetic Plains (IGP) in southern Asia, for more than a month, disrupting daily life of millions of people inhabiting the IGP. The widespread nature of the fog is frequently visible in satellite imagery, extending over a stretch of ~1500 km; that covers parts of Pakistan, northern India, Nepal and Bangladesh. Both, haze and fog are a tightly-coupled system over the IGP, during winter months, and have been a major environmental/climatic issue since the past several decades. Trends in poor visibility suggest a significant increase in worsening air quality and foggy days over the IGP. The persistent and widespread nature of the winter haze and fog is strongly influenced by the regional meteorology during wintertime, i.e. a stable boundary layer, low temperatures, high relative humidity and light winds. The valley-type topography of the IGP, adjacent to the towering Himalaya, and high concentrations of pollution aerosols, further favors the persistence of hazy/foggy conditions. A satellite-based observational portrayal will be presented, using various cloud, aerosol and radiation datasets, to characterize the widespread nature of winter haze and fog, based on a multi-sensor assessment from MODIS, CERES, AVHRR and CALIPSO datasets. More specifically, based on these observations, we will present results on: long-term trends/variability of winter haze and fog, vertical characterization of aerosol/fog/low-clouds, as well as assessment of the direct radiative effect of the region-wide haze/fog system. Results from this work are anticipated to shed light on the overall interactions within the highly persistent and tightly-coupled haze-fog phenomena. Additionally, against the backdrop of a changing climate scenario, possible linkages between the winter-time fog cover, regional meteorology and aerosol loading will also be discussed over the IGP.

  16. Chemical composition of fog and cloud water at the Erzgebirge summit, Germany

    NASA Astrophysics Data System (ADS)

    Schüttauf, S.; Zimmermann, F.; Matschullat, J.

    2010-07-01

    The Erzgebirge as part of the former "Black Triangle" was one of the most polluted forested areas in Central Europe. The local climate is characterized by above-average stable air stratification leading to an above-average amount of inversions with advection fog. Thus, "acid fog" was thought to play an important role in the acidic deposition and in the forest decline on both sides of the Erzgebirge ridge (800 - 900 m a.s.l.). The last data on chemical composition and deposition of fog and cloud water were reported from the 1990's. This work determined the current chemical composition of fog and cloud water from the region in respect to the 1999 Gothenburg protocol. Chemical composition data of fog samples are reported from two sites: (1) Zinnwald, 877 m a.s.l., eastern Erzgebirge, and (2) Fichtelberg, 1214 m a.s.l. The latter results are the first data on the chemical composition of cloud water from that site. Passive fog collectors were used, and only exposed when fog occurred. Two collectors at Zinnwald (one for ion analysis and one for trace elements) and one collector at Fichtelberg were used. Electrical conductivity, pH-value, and the concentration of major ions and trace metals (Ba, Pb, Zn, Al, Mn, Ti, V, Ni, Cu, Sr, Cd, Sb, As, Cr) were determined. TOC was analysed in selected samples. Fog frequency in the investigation period (10.2009 - 12.2009) was comparable to long-term observations. Modelled liquid water contents (LWC) were in the range of typical values for German low elevation mountains. Minimum pH values, 3.5 for Zinnwald and 3.7 for Fichtelberg, were still of phytotoxic relevance. The chemical composition of fog and cloud water differed considerably between the sites. Zinnwald still is a polluted site with high concentrations of sulphate, nitrate, ammonium and organic compounds, while Fichtelberg is much less influenced by air pollution. There, sodium and chloride dominated the composition. At Zinnwald, Al, Zn, Pb, and Cu showed the highest trace

  17. Friend of GATA (FOG) interacts with the nucleosome remodeling and deacetylase complex (NuRD) to support primitive erythropoiesis in Xenopus laevis.

    PubMed

    Mimoto, Mizuho S; Christian, Jan L

    2012-01-01

    Friend of GATA (FOG) plays many diverse roles in adult and embryonic hematopoiesis, however the mechanisms by which it functions and the roles of potential interaction partners are not completely understood. Previous work has shown that overexpression of FOG in Xenopus laevis causes loss of blood suggesting that in contrast to its role in mammals, FOG might normally function to repress erythropoiesis in this species. Using loss-of-function analysis, we demonstrate that FOG is essential to support primitive red blood cell (RBC) development in Xenopus. Moreover, we show that it is specifically required to prevent excess apoptosis of circulating primitive RBCs and that in the absence of FOG, the pro-apoptotic gene Bim-1 is strongly upregulated. To identify domains of FOG that are essential for blood development and, conversely, to begin to understand the mechanism by which overexpressed FOG represses primitive erythropoiesis, we asked whether FOG mutants that are unable to interact with known co-factors retain their ability to rescue blood formation in FOG morphants and whether they repress erythropoiesis when overexpressed in wild type embryos. We find that interaction of FOG with the Nucleosome Remodeling and Deacetylase complex (NuRD), but not with C-terminal Binding Protein, is essential for normal primitive RBC development. In contrast, overexpression of all mutant and wild type constructs causes a comparable repression of primitive erythropoiesis. Together, our data suggest that a requirement for FOG and its interaction with NuRD during primitive erythropoiesis are conserved in Xenopus and that loss of blood upon FOG overexpression is due to a dominant-interfering effect.

  18. Anti-fogging and anti-frosting behaviors of layer-by-layer assembled cellulose derivative thin film

    NASA Astrophysics Data System (ADS)

    Shibraen, Mahmoud H. M. A.; Yagoub, Hajo; Zhang, Xuejian; Xu, Jian; Yang, Shuguang

    2016-05-01

    Two cellulose derivatives, quaternized cellulose (QC) and carboxymethyl cellulose (CMC), were layer-by-layer (LbL) assembled to prepare a thin film. QC was also LbL assembled with two synthetic polyelectrolytes, poly(acrylic acid) (PAA) and poly(styrene sulfonate) (PSS), separately. The anti-fogging and anti-frosting properties of the assembled films were studied. QC/CMC thin film exhibits anti-fogging and anti-frosting behaviors, whereas QC/PAA and QC/PSS films do not have capacity for anti-fogging and anti-frosting. The anti-fogging and anti-frosting properties of QC/CMC film are attributed to that water molecules can be quickly adsorbed into the matrix of the film. The water adsorption of QC/CMC film was illustrated by the optical thickness increment.

  19. Secondary organic aerosol formation in cloud and fog droplets: a literature evaluation of plausibility

    NASA Astrophysics Data System (ADS)

    Blando, James D.; Turpin, Barbara J.

    This paper investigates the hypothesis that cloud and fog processes produce fine organic particulate matter in the atmosphere. The evidence provided suggests that cloud and fog processes could be important contributors to secondary organic aerosol formation, and the contribution of this formation pathway should be further investigated. This conclusion is based on the following observations: (1) many organic vapors present in the atmosphere are sorbed by suspended droplets and have been measured in cloud and fog water, (2) organics participate in aqueous-phase reactions, and (3) organic particulate matter is sometimes found in the size mode attributed to cloud processing (i.e. the droplet mode). Specific compounds identified as potential precursors include aldehydes (e.g. formaldehyde, acetaldehyde, and propionaldehyde), acetone, alcohols (e.g. methanol, ethanol, 2-propanol, and phenol), monocarboxylic acids, and organic peroxides. Carboxylic acids (e.g. diacids and oxo-acids), glyoxal, esters, organosulfur compounds, polyols, amines and amino acids are potential products of cloud and fog processing.

  20. Droplet size of cooling tower fog.

    PubMed

    Rothman, T; Ledbetter, J O

    1975-01-01

    Fog from cooling towers causes problems of visibility and icing along roadways adjacent to the towers; moreover, the visible plume from the towers offers difficulty in that it is equated by much of the public with air pollution. It is desirable to know the size of the fog droplets in order to plan abatement procedures and to determine the airborne lifetimes of such fogs. The methodology involved capturing the droplets on slides coated with a vaseline-mineral oil mixture, making photomicrographs of the droplets, counting and sizing the droplets into eight droplet diameter increments; namely less than 5 mum, 5-10 mum, 10-20 mum, 20-40 mum, 40-60 mum, 60-80 mum, 80-100 mum, and greater than 100 mum. The resulting distribution was similar to that for natural fogs and clouds; i.e., it was bi-modal, the first mode at less than 5 mum containing the vast majority of the droplets, and the second at 20-40 mum. This study agrees with others that the size distribution of a fog in a saturated environment is continuously changing, with the smaller droplets tending to evaporate and the larger ones tending to grow, thus shifting the second mode toward larger sizes.

  1. 7. Fog signal house and shed, view south, north and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Fog signal house and shed, view south, north and west sides of fog signal house, northeast and northwest sides of shed - Whitehead Light Station, Whitehead Island, East northeast of Tenants Harbor, Spruce Head, Knox County, ME

  2. Physical ecology of hypolithic communities in the central Namib Desert: The role of fog, rain, rock habitat, and light

    NASA Astrophysics Data System (ADS)

    Warren-Rhodes, Kimberley A.; McKay, Christopher P.; Boyle, Linda Ng; Wing, Michael R.; Kiekebusch, Elsita M.; Cowan, Don A.; Stomeo, Francesca; Pointing, Stephen B.; Kaseke, Kudzai F.; Eckardt, Frank; Henschel, Joh R.; Anisfeld, Ari; Seely, Mary; Rhodes, Kevin L.

    2013-12-01

    microbial communities are productive niches in deserts worldwide, but many facets of their basic ecology remain unknown. The Namib Desert is an important site for hypolith study because it has abundant quartz rocks suitable for colonization and extends west to east across a transition from fog- to rain-dominated moisture sources. We show that fog sustains and impacts hypolithic ecology in several ways, as follows: (1) fog effectively replaces rainfall in the western zone of the central Namib to enable high (≥95%) hypolithic abundance at landscape (1-10 km) and larger scales; and (2) high water availability, through fog (western zone) and/or rainfall (eastern zone), results in smaller size-class rocks being colonized (mean 6.3 ± 1.2 cm) at higher proportions (e.g., 98% versus approximately 3%) than in previously studied hyperarid deserts. We measured 0.1% of incident sunlight as the lower limit for hypolithic growth on quartz rocks in the Namib and found that uncolonized ventral rock surfaces were limited by light rather than moisture. In situ monitoring showed that although rainfall supplied more liquid water (36 h) per event than fog (mean 4 h), on an equivalent annual basis, fog provided nearly twice as much liquid water as rainfall to the hypolithic zone. Hypolithic abundance reaches 100% at a mean annual precipitation (MAP) of approximately 40-60 mm, but at a much lower MAP (approximately 25 mm) when moisture from fog is available.

  3. Urban Air Pollution from Ethanol (E85) in the Presence of Aqueous Aerosols and Fog

    NASA Astrophysics Data System (ADS)

    Ginnebaugh, D. L.; Jacobson, M. Z.

    2010-12-01

    This is a study to examine the effect of ethanol (E85) versus gasoline on urban air pollution in the presence of aqueous aerosols and fog. In previous work, we analyzed the temperature-dependence of ethanol and gasoline exhaust chemistry and its impact on urban air pollution considering only gas-phase chemistry. We used the near-explicit Master Chemical Mechanism (MCM, version 3.1, LEEDS University) with the SMVGEAR II chemical ordinary differential solver to provide the speed necessary to simulate explicit chemistry. The MCM has over 13,500 organic reactions and 4,600 species. SMVGEAR II is a sparse-matrix Gear solver that reduces the computation time significantly while maintaining any specified accuracy. We found that the average ozone concentrations through the range of temperatures tested could be higher with E85 than with gasoline by up to 8 parts per billion volume (ppbv) at room temperature but much higher at cold temperatures and low sunlight (winter conditions) for a region with a high nitrogen oxide (NOx) to non-methane organic gases (NMOG) ratio. We also found that the solution to chemistry in a 3-D urban airshed model was practical. We now extend our study to include aqueous chemistry in the presence of aerosols and fog. We combine the Chemical Aqueous Phase Radical Mechanism, CAPRAM 3.0 with the MCM 3.1 and gas-particle transfer in box model calculations. CAPRAM treats aqueous phase chemistry among 390 species and 829 reactions (including 51 gas-to-aqueous phase reactions). We investigate the impact aqueous reactions have on unburned ethanol and acetaldehyde mixing ratios in the atmosphere in particular because acetaldehyde is an ozone precursor and carcinogen, and aqueous oxidation has potential to speed the conversion of unburned ethanol to acetaldehyde. Acetaldehyde also forms acetic acid in aqueous solution. Acetic acid vapor is an eye, nose, and lung irritant, so both species contribute negatively to human health. We look at the impact of aerosol

  4. Anti-fog composition. [for prevention of fogging on surfaces such as space helmet visors and windshields

    NASA Technical Reports Server (NTRS)

    Morrison, H. D.; Carmin, D. L., Jr. (Inventor)

    1974-01-01

    An anti-fog composition is described for the prevention of fogging on surfaces such as space helmet visors, spacecraft windows, and windshields. It is composed of a surface active agent, water, and an oil time extender.

  5. Mosquito flight failure in heavy fog

    NASA Astrophysics Data System (ADS)

    Dickerson, Andrew; Telljohann, Luke; Thornton, Lee-Ellen; Moyer, Caitlin; Hu, David

    2012-11-01

    Mosquitoes thrive during rainfall and high humidity. We previously found that mosquitoes are successful fliers through rainfall. Heavy fog, consisting of drops three orders of magnitude smaller in mass than raindrops, presents an environment in which mosquitoes cannot maintain flight. Through high-speed videography, we observe mosquitoes reduce wingbeat frequency in heavy fog, but retain the ability to generate sufficient force to lift their bodies, even after significant dew deposition. They are unable, however, to maintain an upright position required for sustainable flight. A mosquito's primary flight control mechanism is its halteres, small knobbed structures evolved from the hind wings, which flap anti-phase with the wings and provide gyroscopic feedback through Coriolis forces. Though the halteres are hydrophobic, repeated collisions with 10-micron fog particles hinders flight control, leading to flight failure.

  6. 20 years of KVH fiber optic gyro technology: the evolution from large, low performance FOGs to compact, precise FOGs and FOG-based inertial systems

    NASA Astrophysics Data System (ADS)

    Napoli, Jay

    2016-05-01

    Precision fiber optic gyroscopes (FOGs) are critical components for an array of platforms and applications ranging from stabilization and pointing orientation of payloads and platforms to navigation and control for unmanned and autonomous systems. In addition, FOG-based inertial systems provide extremely accurate data for geo-referencing systems. Significant improvements in the performance of FOGs and FOG-based inertial systems at KVH are due, in large part, to advancements in the design and manufacture of optical fiber, as well as in manufacturing operations and signal processing. Open loop FOGs, such as those developed and manufactured by KVH Industries, offer tactical-grade performance in a robust, small package. The success of KVH FOGs and FOG-based inertial systems is due to innovations in key fields, including the development of proprietary D-shaped fiber with an elliptical core, and KVH's unique ThinFiber. KVH continually improves its FOG manufacturing processes and signal processing, which result in improved accuracies across its entire FOG product line. KVH acquired its FOG capabilities, including its patented E•Core fiber, when the company purchased Andrew Corporation's Fiber Optic Group in 1997. E•Core fiber is unique in that the light-guiding core - critical to the FOG's performance - is elliptically shaped. The elliptical core produces a fiber that has low loss and high polarization-maintaining ability. In 2010, KVH developed its ThinFiber, a 170-micron diameter fiber that retains the full performance characteristics of E•Core fiber. ThinFiber has enabled the development of very compact, high-performance open-loop FOGs, which are also used in a line of FOG-based inertial measurement units and inertial navigation systems.

  7. Oxygen Isotopic Composition of Nitrate and Sulfate in Fog and River water in Podocarpus National Forest, Ecuador

    NASA Astrophysics Data System (ADS)

    Brothers, L. A.; Fabian, P.; Thiemens, M. H.

    2006-12-01

    The eastern slopes of the Andean rainforests of Ecuador possess some of the highest plant biodiversity found on the planet; however, these ecosystems are in jeopardy because region is experiences one of the highest deforestation rates in South America. This rainforest characterized by high acidity and low nutrient soils and experiences natural process which are both destabilizing and stabilizing to biodiversity rendering this a unique, though sensitive environment. There is increased concern that anthropogenic activities are affecting rainforests and could lead to higher extinction rates, changes in the biodiversity and far reaching effects on the global troposphere. Measurements of nitrate and sulfate in rain and fog water have shown periods of elevated concentrations in the Podocarpus National Park near Loja, Ecuador. These high episodes contribute to annual deposition rates that are comparable to polluted central Europe. Significant anthropogenic sources near this region are lacking and it is believed that the majority of the nitrate and sulfate pollution can be attributed to biomass burning in the Amazon basin. Concentration measurements do not elucidate the source of high nitrate and sulfate pollution; however, by measuring all three stable isotopes of oxygen in nitrate and sulfate from fog and river water provides a new way to examine the impacts of biomass burning on the region. By using stable isotope techniques atmospheric nitrate and sulfate can be resolved from terrestrial sources. This provides an unique way to trace the contributions from the biomass burning and farming sources. Current research at the field station monitors sulfate and nitrate concentrations in rain and fog water by standard methods to investigate water and nutrient pathways along with data from satellite and ground based remote sensing, in-situ observations and numerical models.

  8. Fog reduces transpiration in tree species of the Canarian relict heath-laurel cloud forest (Garajonay National Park, Spain).

    PubMed

    Ritter, Axel; Regalado, Carlos M; Aschan, Guido

    2009-04-01

    The ecophysiologic role of fog in the evergreen heath-laurel 'laurisilva' cloud forests of the Canary Islands has not been unequivocally demonstrated, although it is generally assumed that fog water is important for the survival and the distribution of this relict paleoecosystem of the North Atlantic Macaronesian archipelagos. To determine the role of fog in this ecosystem, we combined direct transpiration measurements of heath-laurel tree species, obtained with Granier's heat dissipation probes, with micrometeorological and artificial fog collection measurements carried out in a 43.7-ha watershed located in the Garajonay National Park (La Gomera, Canary Islands, Spain) over a 10-month period. Median ambient temperature spanned from 7 to 15 degrees C under foggy conditions whereas higher values, ranging from 9 to 21 degrees C, were registered during fog-free periods. Additionally, during the periods when fog water was collected, global solar radiation values were linearly related (r2=0.831) to those under fog-free conditions, such that there was a 75+/-1% reduction in median radiation in response to fog. Fog events greatly reduced median diurnal tree transpiration, with rates about 30 times lower than that during fog-free conditions and approximating the nighttime rates in both species studied (the needle-like leaf Erica arborea L. and the broadleaf Myrica faya Ait.). This large decrease in transpiration in response to fog was independent of the time of the day, tree size and species and micrometeorological status, both when expressed on a median basis and in cumulative terms for the entire 10-month measuring period. We conclude that, in contrast to the turbulent deposition of fog water droplets on the heath-laurel species, which may be regarded as a localized hydrological phenomenon that is important for high-altitude wind-exposed E. arborea trees, the cooler, wetter and shaded microenvironment provided by the cloud immersion belt represents a large-scale effect

  9. Fog reduces transpiration in tree species of the Canarian relict heath-laurel cloud forest (Garajonay National Park, Spain).

    PubMed

    Ritter, Axel; Regalado, Carlos M; Aschan, Guido

    2009-04-01

    The ecophysiologic role of fog in the evergreen heath-laurel 'laurisilva' cloud forests of the Canary Islands has not been unequivocally demonstrated, although it is generally assumed that fog water is important for the survival and the distribution of this relict paleoecosystem of the North Atlantic Macaronesian archipelagos. To determine the role of fog in this ecosystem, we combined direct transpiration measurements of heath-laurel tree species, obtained with Granier's heat dissipation probes, with micrometeorological and artificial fog collection measurements carried out in a 43.7-ha watershed located in the Garajonay National Park (La Gomera, Canary Islands, Spain) over a 10-month period. Median ambient temperature spanned from 7 to 15 degrees C under foggy conditions whereas higher values, ranging from 9 to 21 degrees C, were registered during fog-free periods. Additionally, during the periods when fog water was collected, global solar radiation values were linearly related (r2=0.831) to those under fog-free conditions, such that there was a 75+/-1% reduction in median radiation in response to fog. Fog events greatly reduced median diurnal tree transpiration, with rates about 30 times lower than that during fog-free conditions and approximating the nighttime rates in both species studied (the needle-like leaf Erica arborea L. and the broadleaf Myrica faya Ait.). This large decrease in transpiration in response to fog was independent of the time of the day, tree size and species and micrometeorological status, both when expressed on a median basis and in cumulative terms for the entire 10-month measuring period. We conclude that, in contrast to the turbulent deposition of fog water droplets on the heath-laurel species, which may be regarded as a localized hydrological phenomenon that is important for high-altitude wind-exposed E. arborea trees, the cooler, wetter and shaded microenvironment provided by the cloud immersion belt represents a large-scale effect

  10. Extreme haze pollution in Beijing during January 2013: chemical characteristics, formation mechanism and role of fog processing

    NASA Astrophysics Data System (ADS)

    Huang, K.; Zhuang, G.; Wang, Q.; Fu, J. S.; Lin, Y.; Liu, T.; Han, L.; Deng, C.

    2014-03-01

    Severe haze hovered over large areas of China in January 2013 right after the public release of PM2.5 data of major cities in China at the very first time. This historical severe haze emerged over the northern China with monthly average concentrations of PM2.5, SO2, and NO2 exceeding 225, 200, and 80 μg m-3, respectively. Surface aerosol mean concentration of Beijing in January 2013 reached record high (only slightly lower than 2006) compared to historical data from 2003-2012, but with the largest daily fluctuation. Anomalous meteorological conditions in 2013 compared to the mean climatology from 2007-2012 were especially favorable for the formation of haze, such as higher humidity, lower temperature, lower PBL height, lower wind speed, and the high frequency of fog occurrences. The field campaign in Beijing showed an extremely high PM2.5 average concentration of 299.2 ± 79.1μg m-3 with extremely low visibility of 0.92 ± 0.82 km during an episode of high relative humidity with fog events. High AOD (Aerosol Optical Depth) was observed during fog days but with relatively low Angstrom exponent (< 1.0), suggesting the modification of fog processing on the particle size. Major aerosol chemical species, such as SO42-, NO3-, NH4+, Cl-, K+, and C2O42- presented an explicit exponential growth relationship with relative humidity, suggesting the significant impact of aerosol hygroscopicity on the visibility impairment. SO42- increased ∼5 folds while NO3-, NH4+, and C2O42- increased ∼3 folds in the fog days compared to the non-fog days. Aerosol in fog days was much more acidic than that in non-fog days. The in situ aerosol pH ranged from -0.78 to 0.14 in fog days based on the E-AIM model simulation. Bisulfate (HSO42-) accounted for 52% of the total sulfate and free hydrogen ion (H+Aq) accounted for 27% of the total acids in average. Enhanced coal combustion during the winter heating season along with traffic and industrial emissions were recognized to be the major

  11. Warm fog dissipation using large volume water sprays

    NASA Technical Reports Server (NTRS)

    Keller, Vernon W. (Inventor)

    1988-01-01

    To accomplish the removal of warm fog about an area such as an airport runway, a plurality of nozzles along a line adjacent the area propelled water jets through the fog to heights of approximately twenty-five meters. Each water jet breaks up forming a water drop size distribution that falls through the fog overtaking, colliding, and coalescing with individual fog droplets and thereby removes the fog. A water retrieval system is used to collect the water and return it to reservoirs for pumping it to the nozzles once again.

  12. Spatiotemporal Variability of Surface Meteorological Variables During Fog and No-Fog Events in the Heber Valley, UT; Selected Case Studies From MATERHORN-Fog

    NASA Astrophysics Data System (ADS)

    van den Bossche, Michael; De Wekker, Stephan F. J.

    2016-08-01

    We investigated the spatiotemporal variability of surface meteorological variables in the nocturnal boundary layer using six automatic weather stations deployed in the Heber Valley, UT, during the MATERHORN-Fog experiment. The stations were installed on the valley floor within a 1.5 km × 0.8 km area and collected 1-Hz wind and pressure data and 0.2-Hz temperature and humidity data. We describe the weather stations and analyze the spatiotemporal variability of the measured variables during three nights with radiative cooling. Two nights were characterized by the presence of dense ice fog, one night with a persistent (`heavy') fog, and one with a short-lived (`moderate') fog, while the third night had no fog. Frost-point depressions were larger preceding the night without fog and showed a continued decrease during the no-fog night. On both fog nights, the frost-point depression reached values close to zero early in the night, but ~5 h earlier on the heavy-fog night than on the moderate-fog night. Spatial variability of temperature and humidity was smallest during the heavy-fog night and increased temporarily during short periods when wind speeds increased and the fog lifted. During all three nights, wind speeds did not exceed 2 m/s. The temporal variability of the wind speed and direction was larger during the fog nights than during the no-fog nights, but was particularly large during the heavy-fog night. The large variability corresponded with short-lived (5-10 min) pressure variations with amplitudes on the order of 0.5 hPa, indicating gravity wave activity. These pressure fluctuations occurred at all stations and were correlated in particular with variability in wind direction. Although not able to provide a complete picture of the nocturnal boundary layer, our low-cost weather stations were able to continuously collect data that were comparable to those of nearby research-grade instruments. From these data, we distinguished between fog and no-fog events

  13. Spatiotemporal Variability of Surface Meteorological Variables During Fog and No-Fog Events in the Heber Valley, UT; Selected Case Studies From MATERHORN-Fog

    NASA Astrophysics Data System (ADS)

    van den Bossche, Michael; De Wekker, Stephan F. J.

    2016-09-01

    We investigated the spatiotemporal variability of surface meteorological variables in the nocturnal boundary layer using six automatic weather stations deployed in the Heber Valley, UT, during the MATERHORN-Fog experiment. The stations were installed on the valley floor within a 1.5 km × 0.8 km area and collected 1-Hz wind and pressure data and 0.2-Hz temperature and humidity data. We describe the weather stations and analyze the spatiotemporal variability of the measured variables during three nights with radiative cooling. Two nights were characterized by the presence of dense ice fog, one night with a persistent (`heavy') fog, and one with a short-lived (`moderate') fog, while the third night had no fog. Frost-point depressions were larger preceding the night without fog and showed a continued decrease during the no-fog night. On both fog nights, the frost-point depression reached values close to zero early in the night, but ~5 h earlier on the heavy-fog night than on the moderate-fog night. Spatial variability of temperature and humidity was smallest during the heavy-fog night and increased temporarily during short periods when wind speeds increased and the fog lifted. During all three nights, wind speeds did not exceed 2 m/s. The temporal variability of the wind speed and direction was larger during the fog nights than during the no-fog nights, but was particularly large during the heavy-fog night. The large variability corresponded with short-lived (5-10 min) pressure variations with amplitudes on the order of 0.5 hPa, indicating gravity wave activity. These pressure fluctuations occurred at all stations and were correlated in particular with variability in wind direction. Although not able to provide a complete picture of the nocturnal boundary layer, our low-cost weather stations were able to continuously collect data that were comparable to those of nearby research-grade instruments. From these data, we distinguished between fog and no-fog events

  14. Brain "fog," inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin.

    PubMed

    Theoharides, Theoharis C; Stewart, Julia M; Hatziagelaki, Erifili; Kolaitis, Gerasimos

    2015-01-01

    Brain "fog" is a constellation of symptoms that include reduced cognition, inability to concentrate and multitask, as well as loss of short and long term memory. Brain "fog" characterizes patients with autism spectrum disorders (ASDs), celiac disease, chronic fatigue syndrome, fibromyalgia, mastocytosis, and postural tachycardia syndrome (POTS), as well as "minimal cognitive impairment," an early clinical presentation of Alzheimer's disease (AD), and other neuropsychiatric disorders. Brain "fog" may be due to inflammatory molecules, including adipocytokines and histamine released from mast cells (MCs) further stimulating microglia activation, and causing focal brain inflammation. Recent reviews have described the potential use of natural flavonoids for the treatment of neuropsychiatric and neurodegenerative diseases. The flavone luteolin has numerous useful actions that include: anti-oxidant, anti-inflammatory, microglia inhibition, neuroprotection, and memory increase. A liposomal luteolin formulation in olive fruit extract improved attention in children with ASDs and brain "fog" in mastocytosis patients. Methylated luteolin analogs with increased activity and better bioavailability could be developed into effective treatments for neuropsychiatric disorders and brain "fog." PMID:26190965

  15. Brain "fog," inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin.

    PubMed

    Theoharides, Theoharis C; Stewart, Julia M; Hatziagelaki, Erifili; Kolaitis, Gerasimos

    2015-01-01

    Brain "fog" is a constellation of symptoms that include reduced cognition, inability to concentrate and multitask, as well as loss of short and long term memory. Brain "fog" characterizes patients with autism spectrum disorders (ASDs), celiac disease, chronic fatigue syndrome, fibromyalgia, mastocytosis, and postural tachycardia syndrome (POTS), as well as "minimal cognitive impairment," an early clinical presentation of Alzheimer's disease (AD), and other neuropsychiatric disorders. Brain "fog" may be due to inflammatory molecules, including adipocytokines and histamine released from mast cells (MCs) further stimulating microglia activation, and causing focal brain inflammation. Recent reviews have described the potential use of natural flavonoids for the treatment of neuropsychiatric and neurodegenerative diseases. The flavone luteolin has numerous useful actions that include: anti-oxidant, anti-inflammatory, microglia inhibition, neuroprotection, and memory increase. A liposomal luteolin formulation in olive fruit extract improved attention in children with ASDs and brain "fog" in mastocytosis patients. Methylated luteolin analogs with increased activity and better bioavailability could be developed into effective treatments for neuropsychiatric disorders and brain "fog."

  16. The ac and dc performance of polymeric insulating materials under accelerated aging in a fog chamber

    SciTech Connect

    Gorur, R.S. ); Cherney, E.A. ); Hackam, R. )

    1988-10-01

    The paper presents the results of the dc performance of polymeric insulating materials in a fog chamber. The materials evaluated in fog produced from low (250 ..mu..S/cm) and high (1000 ..mu..S/cm) conductivity water include cylindrical rod samples of high temperature vulcanized (HTV) silicone rubber and ethylene propylene diene monomer (EPDM) rubber containing various amounts of either alumina trihydrate (ATH) or silica fillers, or both. Comparison is made of material performance obtained with ac which was reported in an earlier study. In both low and high conductivity fog, the time to failure with ac and +dc was very similar, but a reduction by a factor of about four was observed in the time to failure with -dc. For both ac and dc, silicone rubber performed better than EPDM samples in low conductivity fog, while the order of performance was reversed in high conductivity fog. A theoretical model to determine the effect of dry band discharges on material is presented. Good agreement of the predicted behavior of materials with the experimental findings is shown.

  17. Experiment of polarization transmission characteristics and polarization imaging in simulation smoke/fog environment

    NASA Astrophysics Data System (ADS)

    Duan, Jin; Zhan, Juntong; Zhang, Su; Zhao, Changxia; Peng, Jie; Lei, Yi; Fu, Qiang

    2015-10-01

    In light transmission processing, light is effected by the fog/haze/smoke/dust environment usually. Thus reduce the capability of traditional photo-electric instrument in detection, transmission, imaging, because of the attenuation, scattering, absorbing of the atmosphere. Polarization transmission characteristics exist the potential possibility in observing object through fog and smoke, increasing observation distance, improve the environment adaptability of the photo-electric instrument. The influence of polarization transmission characteristics are analyzed by environment testing experiment in this paper, including light intensity, degree of polarization, angle of polarization etc. We research smoke and fog environment simulation technology, builds the process-controlled and parameter-measured indoor equipment to simulate smoke/fog environment. The experiments of the polarization characteristic are tested in two kinds of transmission mediums separately, which are water fog and oil smoke. The attenuation ratio is measured in different kinds of smoke concentrations. Polarization imaging experiment are tested separately in different kinds of illuminance lights, which are daylight lamp, LED lights and projector lights. The images are captured by imaging CCD with linearly polarized filters on degree 0, 60, 120. The polarization images on three directions are processed by image infuse algorithm. The experiment results are provided as the theory foundation and data reference in field of polarization transmission.

  18. Chemical composition of fog water in Nanjing area of China and its related fog microphysics

    NASA Astrophysics Data System (ADS)

    Lu, Chunsong; Niu, Shengjie; Tang, Lili; Lv, Jingjing; Zhao, Lijuan; Zhu, Bin

    2010-07-01

    Fog samples were collected at Pancheng in the Nanjing area of China during December 2006 and December 2007. Fog droplet spectra, surface meteorological elements and visibility were also measured during the same period. The data from PM 10, SO 2 and NO 2 measurements were obtained from the air quality monitoring networks of Nanjing. The total ionic concentration (TIC) and electrical conductivity (EC) in fog samples, and the local pollutant emissions were one or two orders of magnitude higher than those found in Europe or South America for instance. Pollutants were expected to be mainly from local sources, including factories, plants, freeways, soil sources, house construction, and biomass burning. Advection also contributed to pollution levels in radiation-advection fogs. The scavenging of NH 3 and coarse particles by fog droplets was the main cause for the high mean pH value of 5.9. In-phase temporal evolution of TIC, [SO 42-], [NO 3-], SO 2, NO 2, PM 10 and S/LWC (S: the surface area of fog droplets per unit volume of air; LWC: liquid water content) was found to be due to the interaction of air pollutants and fog droplets, change of air mass due to advection, and so on. S/LWC seemed to be a better indicator for describing the relationship between TIC and microphysics with respect to LWC. A formula between TIC and S/LWC was derived and the related parameters were discussed. Depositions of chemical species in fog cases were estimated and the result showed that deposition was efficient.

  19. Holographic Imaging In Dense Artificial Fog

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Marzwell, Neville

    1996-01-01

    Artificial fog serves as volume-projection medium for display of three-dimensional image. Projection technique enables display of images for variety of purposes, possibly including entertainment, indoor and outdoor advertising, medical diagnostics and image representations for surgical procedures, and education.

  20. Musings on Willower's "Fog": A Response.

    ERIC Educational Resources Information Center

    English, Fenwick

    1998-01-01

    Professor Willower complains about the "fog" encountered in postmodernist literature and the author's two articles in "Journal of School Leadership." On closer examination, this miasma is simply the mildew on Willower's Cartesian glasses. Educational administration continues to substitute management and business fads for any real effort to create…

  1. FOG Random Drift Signal Denoising Based on the Improved AR Model and Modified Sage-Husa Adaptive Kalman Filter

    PubMed Central

    Sun, Jin; Xu, Xiaosu; Liu, Yiting; Zhang, Tao; Li, Yao

    2016-01-01

    In order to reduce the influence of fiber optic gyroscope (FOG) random drift error on inertial navigation systems, an improved auto regressive (AR) model is put forward in this paper. First, based on real-time observations at each restart of the gyroscope, the model of FOG random drift can be established online. In the improved AR model, the FOG measured signal is employed instead of the zero mean signals. Then, the modified Sage-Husa adaptive Kalman filter (SHAKF) is introduced, which can directly carry out real-time filtering on the FOG signals. Finally, static and dynamic experiments are done to verify the effectiveness. The filtering results are analyzed with Allan variance. The analysis results show that the improved AR model has high fitting accuracy and strong adaptability, and the minimum fitting accuracy of single noise is 93.2%. Based on the improved AR(3) model, the denoising method of SHAKF is more effective than traditional methods, and its effect is better than 30%. The random drift error of FOG is reduced effectively, and the precision of the FOG is improved. PMID:27420062

  2. FOG Random Drift Signal Denoising Based on the Improved AR Model and Modified Sage-Husa Adaptive Kalman Filter.

    PubMed

    Sun, Jin; Xu, Xiaosu; Liu, Yiting; Zhang, Tao; Li, Yao

    2016-01-01

    In order to reduce the influence of fiber optic gyroscope (FOG) random drift error on inertial navigation systems, an improved auto regressive (AR) model is put forward in this paper. First, based on real-time observations at each restart of the gyroscope, the model of FOG random drift can be established online. In the improved AR model, the FOG measured signal is employed instead of the zero mean signals. Then, the modified Sage-Husa adaptive Kalman filter (SHAKF) is introduced, which can directly carry out real-time filtering on the FOG signals. Finally, static and dynamic experiments are done to verify the effectiveness. The filtering results are analyzed with Allan variance. The analysis results show that the improved AR model has high fitting accuracy and strong adaptability, and the minimum fitting accuracy of single noise is 93.2%. Based on the improved AR(3) model, the denoising method of SHAKF is more effective than traditional methods, and its effect is better than 30%. The random drift error of FOG is reduced effectively, and the precision of the FOG is improved. PMID:27420062

  3. FOG Random Drift Signal Denoising Based on the Improved AR Model and Modified Sage-Husa Adaptive Kalman Filter.

    PubMed

    Sun, Jin; Xu, Xiaosu; Liu, Yiting; Zhang, Tao; Li, Yao

    2016-07-12

    In order to reduce the influence of fiber optic gyroscope (FOG) random drift error on inertial navigation systems, an improved auto regressive (AR) model is put forward in this paper. First, based on real-time observations at each restart of the gyroscope, the model of FOG random drift can be established online. In the improved AR model, the FOG measured signal is employed instead of the zero mean signals. Then, the modified Sage-Husa adaptive Kalman filter (SHAKF) is introduced, which can directly carry out real-time filtering on the FOG signals. Finally, static and dynamic experiments are done to verify the effectiveness. The filtering results are analyzed with Allan variance. The analysis results show that the improved AR model has high fitting accuracy and strong adaptability, and the minimum fitting accuracy of single noise is 93.2%. Based on the improved AR(3) model, the denoising method of SHAKF is more effective than traditional methods, and its effect is better than 30%. The random drift error of FOG is reduced effectively, and the precision of the FOG is improved.

  4. Exposure standard for fog oil. Technical report, Dec 89-Nov 90

    SciTech Connect

    Palmer, W.G.

    1990-11-15

    Effects of mineral oils in animals and humans are evaluated and serve as the basis for the development of an exposure standard for fog oil. Considered are health hazards associated with fog oil purchased before and after the Military Specification was amended in April 1986 to exclude carcinogens. While repeated exposure to conventionally-refined mineral oils may cause pulmonary disease as well as severe dermatoses and cancer of the skin and scrotum, lipoid pneumonia is the major health hazard associated with highly refined mineral oils such as fog oils purchased after April 1986. While the course of lipoid pneumonia can be asymptomatic in some individuals, in others its symptoms can range from occasional cough to severe, debilitating dyspnea and pulmonary illness, occasionally ending in death.

  5. Fog Events at Maceio Airport on the Northern Coast of Brazil During 2002-2005 and 2007

    NASA Astrophysics Data System (ADS)

    Fedorova, Natalia; Levit, Vladimir; de Souza, José Leonaldo; Silva, Aliton Oliveira; Afonso, Joao M. Sousa; Teodoro, Iedo

    2015-10-01

    There were eight fog events in five years at Maceio international airport on the northern coast of Brazil, and all were analyzed. Fog duration was short and its intensity was weak or moderate. The principal objectives of the study were: (1) analysis of the physical processes of fog formation (synoptic and thermodynamic conditions and processes), (2) PAFOG model testing, and (3) estimation of the effect of vegetation on fog forecast. Cyclonic curvature and divergence of the air current over the ocean at low levels and anticyclonic curvature at high levels were associated with the fog. Weak lifting at low levels was identified by the NCEP/DOE II, ECMWF, and WRF models for all eight events. Sinking at high levels was dominant in the ECMWF and WRF models. Absence of thermal inversion and conditional instability at low levels was identified by the NCEP/DOE II and ECMWF models. According to the WRF model a typical temperature profile during fog comprises three layers: (1) a very thin layer (up to 166 m, 985 hPa) of temperature inversion with very high humidity; (2) a conditional layer of instability from 985-860 hPa; and (3) a dry and stable layer above 860 hPa. Moderate fog with visibility between 200 and 300 m was associated with ocean cooling whereas weak fog was associated with ocean warming. A warm oscillation on the sea surface near the Brazilian northeast was observed for all fog events. It was found there was colder air over the warmer water near the coast. Weak confluence in troughs at low levels contributes to weak lifting at low levels. This current creates conditions resulting in humidity increase. A warmer sea surface contributes to more evaporation and, as a consequence, increases the amount of water vapor in the surrounding air at low levels near the coast. The PAFOG model was used to forecast the fog for three events (i.e., for all cases possible), and was satisfactory for two cases. Satisfactory results for fog duration and intensity were obtained with 9

  6. Coalescence of fog droplets: Differential fog water deposition on wet and dry forest canopies

    NASA Astrophysics Data System (ADS)

    Tobón, C.; Barrero, J.

    2010-07-01

    The Páramo ecosystem is a high-altitude (2800 - 4500 masl), natural ecosystems which comprises approximately 42000 km2, extending across the Andes from north of Peru, Ecuador, Colombia and western part of Venezuela. Andean páramos are widely considered to be prime suppliers of large volumes of high-quality water for large cities and for hydropower production. As páramos tend to be subjected to persistent fog incidence, fog interception by the vegetation is a common process in these ecosystems, representing not only an extra input of water to the ecosystem but also to suppress evaporation. In this process, small drops of water, transported by the wind, are captured by the surfaces of the vegetation, acting as physical obstacles to the flow of fog. These drops condense in the exposed surfaces and drip towards the ground or evaporate from the surfaces. The quantification of the magnitude of these processes is important for the quantification of the water balance of river basins where these types of ecosystems exist. Although the great hydrological importance of fog in montane tropical ecosystems little is known about its physical principles related to the interception of fog by physical barriers as vegetation, notably the differential behaviour of a wet and dry vegetation in the efficiency of capturing water from the fog. To characterize and quantify this efficiency of páramo vegetation in capturing water from the fog, during wet and dry canopy conditions, an experimental design was set up at the Páramo de Chingaza (Colombia) where paired samples of espeletia branches (dry and wet) were exposed to different fog events, and at the same time Juvik cylinders were exposed by the side of the experimental site, to measured fog inputs. Cylinders were also paired (wet and dry) at the beginning of the experiments. Results indicated that exposed wet and dry samples have a significant difference on the magnitude of water intercepted from the fog, being, in average, the wet

  7. Referenceless Prediction of Perceptual Fog Density and Perceptual Image Defogging.

    PubMed

    Choi, Lark Kwon; You, Jaehee; Bovik, Alan Conrad

    2015-11-01

    We propose a referenceless perceptual fog density prediction model based on natural scene statistics (NSS) and fog aware statistical features. The proposed model, called Fog Aware Density Evaluator (FADE), predicts the visibility of a foggy scene from a single image without reference to a corresponding fog-free image, without dependence on salient objects in a scene, without side geographical camera information, without estimating a depth-dependent transmission map, and without training on human-rated judgments. FADE only makes use of measurable deviations from statistical regularities observed in natural foggy and fog-free images. Fog aware statistical features that define the perceptual fog density index derive from a space domain NSS model and the observed characteristics of foggy images. FADE not only predicts perceptual fog density for the entire image, but also provides a local fog density index for each patch. The predicted fog density using FADE correlates well with human judgments of fog density taken in a subjective study on a large foggy image database. As applications, FADE not only accurately assesses the performance of defogging algorithms designed to enhance the visibility of foggy images, but also is well suited for image defogging. A new FADE-based referenceless perceptual image defogging, dubbed DEnsity of Fog Assessment-based DEfogger (DEFADE) achieves better results for darker, denser foggy images as well as on standard foggy images than the state of the art defogging methods. A software release of FADE and DEFADE is available online for public use: http://live.ece.utexas.edu/research/fog/index.html.

  8. An analysis of fog events at Belgrade International Airport

    NASA Astrophysics Data System (ADS)

    Veljović, Katarina; Vujović, Dragana; Lazić, Lazar; Vučković, Vladan

    2015-01-01

    A preliminary study of the occurrence of fog at Belgrade "Nikola Tesla" Airport was carried out using a statistical approach. The highest frequency of fog has occurred in the winter months of December and January and far exceeded the number of fog days in the spring and the beginning of autumn. The exceptionally foggy months, those having an extreme number of foggy days, occurred in January 1989 (18 days), December 1998 (18 days), February 2005 (17 days) and October 2001 (15 days). During the winter months (December, January and February) from 1990 to 2005 (16 years), fog occurred most frequently between 0600 and 1000 hours, and in the autumn, between 0500 and 0800 hours. In summer, fog occurred most frequently between 0300 and 0600 hours. During the 11-year period from 1995 to 2005, it was found that there was a 13 % chance for fog to occur on two consecutive days and a 5 % chance that it would occur 3 days in a row. In October 2001, the fog was observed over nine consecutive days. During the winter half year, 52.3 % of fog events observed at 0700 hours were in the presence of stratus clouds and 41.4 % were without the presence of low clouds. The 6-h cooling observed at the surface preceding the occurrence of fog between 0000 and 0700 hours ranged mainly from 1 to 4 °C. A new method was applied to assess the probability of fog occurrence based on complex fog criteria. It was found that the highest probability of fog occurrence (51.2 %) takes place in the cases in which the relative humidity is above 97 %, the dew-point depression is 0 °C, the cloud base is lower than 50 m and the wind is calm or weak 1 h before the onset of fog.

  9. Acid rain: effects on fish and wildlife

    SciTech Connect

    Mayer, K.S.; Multer, E.P.; Schreiber, R.K.

    1984-01-01

    The following questions concerning acid rain are discussed: what is acid rain; what causes acid rain; where do sulfur and nitrogen oxides originate; what areas in the U.S. are susceptible to acid rain; are there early warning signals of acidification to aquatic resources; how does acid rain affect fishery resources; does acid rain affect wildlife; and how can effects of acid rain be reduced.

  10. Comparison of Buffer Effect of Different Acids During Sandstone Acidizing

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham; Hamid, Mohamed Ali

    2015-04-01

    The most important concern of sandstone matrix acidizing is to increase the formation permeability by removing the silica particles. To accomplish this, the mud acid (HF: HCl) has been utilized successfully for many years to stimulate the sandstone formations, but still it has many complexities. This paper presents the results of laboratory investigations of different acid combinations (HF: HCl, HF: H3PO4 and HF: HCOOH). Hydrofluoric acid and fluoboric acid are used to dissolve clays and feldspar. Phosphoric and formic acids are added as a buffer to maintain the pH of the solution; also it allows the maximum penetration of acid into the core sample. Different tests have been performed on the core samples before and after the acidizing to do the comparative study on the buffer effect of these acids. The analysis consists of permeability, porosity, color change and pH value tests. There is more increase in permeability and porosity while less change in pH when phosphoric and formic acids were used compared to mud acid. From these results it has been found that the buffer effect of phosphoric acid and formic acid is better than hydrochloric acid.

  11. The chemical composition of fogs and clouds in coastal regions (Invited)

    NASA Astrophysics Data System (ADS)

    Collett, J. L.; Benedict, K. B.; Straub, D.; Lee, T.

    2013-12-01

    Clouds and fogs formed in coastal regions interact strongly with their environment. Coastal regions are especially interesting because they represent an important zone for exchange and mixing of marine and anthropogenic emissions. The chemical compositions of coastal clouds and fogs provide insight into their processing of trace gases and particles in these regional systems. Clouds and fogs both promote the cleansing of the atmosphere by direct or precipitation removal of scavenged gases and particles and enhance production of new particle mass via aqueous phase oxidation of scavenged gases. Here we review observations of coastal fog and cloud composition made along the west coast of the United States, off the coast of northern Chile, and in the northern Pacific. Observations of organic matter, sulfur, nitrogen, and sea salt species will be reviewed in the context of marine and anthropogenic emission sources. Clouds in these regions contain differing mixes of strong and weak acids and bases that give rise to a large pH range. The potential of these clouds for rapid aqueous oxidation of dissolved sulfur dioxide to sulfate will also be examined in light of the important role clouds play in regional and global atmospheric production of sulfate.

  12. The role of emission background on fog chemistry at some selected mountain tops in Poland

    NASA Astrophysics Data System (ADS)

    Godek, M.; Błaś, M.; Polkowska, Z.; Sobik, M.

    2010-07-01

    Sudety Mountains and Western Carpathians form significant orographic thresholds and airflow deformation as a consequence. Fog deposition play a dominant role within the structure of the wet deposition. Intensive development of power industry in surroundings of the mountains resulted in catastrophic ecological disaster in forest ecosystems, which became clearly visible since 1978. Air pollution concentration in Western Sudetes between 1979 and 1982 achieved the highest level ever measured in Europe and pH values of fog and precipitation below 3,8 were observed frequently. Due to this situation only in Polish part of Sudety Mountains over 13500 ha of forest have been destroyed and 92,7% of remaining conifers was classified as partially damaged. Currently pollutants emission decreases, none the less still acquires high level and cumulated effect on soil and trees reacts. Since the beginning of XXI century forest disaster proceeds in the Western Carpathians and the territorial range of disaster still continous to expand. The main goal of the project was to compare chemical structure of fog from different mountainous locations in the context of emission background and different circulation directions. There were 3 measurement points installed for collecting daily samples of fog deposition from February 2009 to January 2010. Each point has been located on the top of the mountain on the altitude range between 1200 and 1400 m a.s.l., as well as selected as a representative for wider mountainous area: Mt. Szrenica (Western Sudety Mountains), Mt. Snieznik (Eastern Sudety Mountains), Mt. Skrzyczne (Western Carpathians). They form horizontal profile from Northwest do Southeast with the lenght about 300 kilometres. Solid and liquid samples of fog were collected daily using passive fog collectors. It was established that the efficiency of fog precipitation decreases significantly from the Western Sudety Mts to the east. Solid fog deposit amounts 4 times higher volume of water at

  13. Rain Enhancement and Fog Elimination by Seeding with Charged Droplets. Part I: Theory and Numerical Simulations.

    NASA Astrophysics Data System (ADS)

    Khain, A.; Arkhipov, V.; Pinsky, M.; Feldman, Y.; Ryabov, Ya.

    2004-10-01

    A new method of droplet collision acceleration, with the purpose of rain enhancement and fog elimination, is proposed. According to the method, some fraction of the droplets is taken from clouds (or fog) themselves, charged, and then injected back into clouds (or fog). To verify the efficiency of the method, a novel model has been developed, allowing simulation of droplet spectrum evolution by collision in case a certain fraction of the droplets in a droplet spectrum is charged. Simulations of droplet spectra evolution include several steps: (a) The forces arising between charged and neutral droplets, as well as between charged droplets, are calculated as the function of the value of the charges, droplet size, and distance between droplets. It is shown that because of the induction effect, significant attraction forces arise between charged and neutral droplets. (b) The results obtained have been used to calculate the collision efficiencies between charged and neutral, as well between charged droplets. As a result, a “four dimensional” table of the collision efficiencies (the collision efficiency is the function of the droplet size and charge) was calculated. The collision efficiencies between charged and neutral droplets turn out to be significantly higher than the pure gravity-induced values. (c) To accomplish these simulations, a novel numerical method of solving the stochastic collision equation has been developed. Cloud droplets are described by a two-dimensional size distribution function in which droplets are characterized by both their mass and charge. (d) This model, with the implemented table of the collision efficiencies, has been used to simulate droplet spectra evolution in clouds and fog in case some fraction of these droplets was charged. Simulations of the effects of seeding by charged droplets have been performed. Evolution of initially narrow droplet size spectra (typical of extremely continental clouds in highly smoky air), in the case of

  14. Assessment of fogging resistance of anti-fog personal eye protection.

    PubMed

    Dain, S J; Hoskin, A K; Winder, C; Dingsdag, D P

    1999-07-01

    The propensity for occupational eye protectors to fog in warm and moist conditions is often offered as a reason by workers not to wear occupational eye protection even where mandatory eye protection areas have been specified. A study of eye protection practices in the New South Wales coal mining industry identified the number one issue in underground coal mine conditions as being fogging of eye safety wear. Conventional anti-fog treatments and cleaners were considered by the miners as completely inadequate in these conditions. At the time of the study claims were being made for a new generation of lens treatments. These merited evaluation. Spectacles and goggles claimed to be fog resistant were obtained from manufacturers and suppliers and subjected to the test set out in BS EN 168 and the compliance criterion of BS EN 166. Some lenses claimed to be fog resistant failed the requirement, some new technology lenses showed arguably superior performance but failed the criterion of the standard. Modifications to the test procedure of BS EN 168 and acceptance criteria of BS EN 166 are proposed.

  15. Extinction of Light during the Fog Life Cycle: a Result from the ParisFog Experiment

    SciTech Connect

    Elias, T.; Haeffelin, M.; Drobinski, P.

    2009-03-11

    Data set acquired by five particle-dedicated instruments set up on the SIRTA experimental site during the ParisFog field campaign are exploited to document microphysical properties of particles contributing to extinction of visible radiation in variable situations. The case study is a 48-hour period when atmospheric conditions are highly variable: relative humidity changes between 50 and 100%, visibility ranges between 35000 and 65 m, the site is either downwind Paris area either under maritime influence. A dense and homogeneous fog formed by radiative cooling during the 18-19 February night. In 7 hours, visibility decreases from 26 000 m to 65 m, because of transported pollution (factor 3 in visibility reduction), aerosol hydration (factor 20) and aerosol activation (factor 6). According to Mie theory, extinction in clear-sky polluted and unpolluted regimes is due equally to Aitken and accumulation modes. Extinction in haze is due to hydrated aerosols distributed in the accumulation mode, for diameter smaller than 2 {mu}m. Hydrated aerosols of the accumulation mode still contribute to 20-30% extinction in the fog. Measurements show that fog droplets, with diameter included between 2 and 10 {mu}m, contribute to 40% extinction during the first hours of the fog.

  16. Long-range polarimetric imaging through fog.

    PubMed

    Fade, Julien; Panigrahi, Swapnesh; Carré, Anthony; Frein, Ludovic; Hamel, Cyril; Bretenaker, Fabien; Ramachandran, Hema; Alouini, Mehdi

    2014-06-20

    We report an experimental implementation of long-range polarimetric imaging through fog over kilometric distance in real field atmospheric conditions. An incoherent polarized light source settled on a telecommunication tower is imaged at a distance of 1.3 km with a snapshot polarimetric camera including a birefringent Wollaston prism, allowing simultaneous acquisition of two images along orthogonal polarization directions. From a large number of acquisitions datasets and under various environmental conditions (clear sky/fog/haze, day/night), we compare the efficiency of using polarized light for source contrast increase with different signal representations (intensity, polarimetric difference, polarimetric contrast, etc.). With the limited-dynamics detector used, a maximum fourfold increase in contrast was demonstrated under bright background illumination using polarimetric difference image.

  17. Fog and rain in the Amazon

    PubMed Central

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H.

    2015-01-01

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents. PMID:26324902

  18. Fog and rain in the Amazon.

    PubMed

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H

    2015-09-15

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents.

  19. Carbon speciation and surface tension of fog

    USGS Publications Warehouse

    Capel, P.D.; Gunde, R.; Zurcher, F.; Giger, W.

    1990-01-01

    The speciation of carbon (dissolved/particulate, organic/inorganic) and surface tension of a number of radiation fogs from the urban area of Zurich, Switzerland, were measured. The carbon species were dominated by "dissolved" organic carbon (DOC; i.e., the fraction that passes through a filter), which was typically present at levels of 40-200 mg/L. Less than 10% of the DOC was identified as specific individual organic compounds. Particulate organic carbon (POC) accounted for 26-41% of the mass of the particles, but usually less than 10% of the total organic carbon mass. Inorganic carbon species were relatively minor. The surface tensions of all the measured samples were less than pure water and were correlated with their DOC concentrations. The combination of high DOC and POC and low surface tension suggests a mechanism for the concentration of hydrophobic organic contaminants in the fog droplet, which have been observed by numerous investigators. ?? 1990 American Chemical Society.

  20. Formation of Oxidized Organic Aerosol (OOA) through Fog Processing in the Po Valley

    NASA Astrophysics Data System (ADS)

    Gilardoni, S.; Paglione, M.; Rinaldi, M.; Giulianelli, L.; Massoli, P.; Hillamo, R. E.; Carbone, S.; Lanconelli, C.; Laaksonen, A. J.; Russell, L. M.; Poluzzi, V.; Fuzzi, S.; Facchini, C.

    2014-12-01

    Aqueous phase chemistry might be responsible for the formation of a significant fraction of the organic aerosol (OA) observed in the atmosphere, and could explain some of the discrepancies between OA concentration and properties predicted by models and observed in the environment. Aerosol - fog interaction and its effect on submicron aerosol properties were investigated in the Po Valley (northern Italy) during fall 2011, in the framework of the Supersite project (ARPA Emilia Romagna). Composition and physical properties of submicron aerosol were measured online by a High Resolution- Time of Flight - Aerosol Mass Spectrometer (HR-TOF-AMS), a Soot Photometer - Aerosol Mass Spectrometer (SP-AMS), and a Tandem Differential Mobility Particle Sizer (TDMPS). Organic functional group analysis was performed off-line by Hydrogen - Nuclear Magnetic Resonance (H-NMR) spectrometry and by Fourier Transform Infrared (FTIR) spectrometry. Aerosol absorption, scattering, and total extinction were measured simultaneously with a Particle Soot Absorption Photometer (PSAP), a Nephelometer, and a Cavity Attenuated Phase Shift Spectrometer particle extinction monitor (CAPS PMex), respectively. Water-soluble organic carbon in fog-water was characterized off-line by HR-TOF-AMS. Fourteen distinct fog events were observed. Fog dissipation left behind an aerosol enriched in particles larger than 400 nm, typical of fog and cloud processing, and dominated by secondary species, including ammonium nitrate, ammonium sulfate and oxidized OA (OOA). Source apportionment of OA allowed us to identify OOA as the difference between total OA and primary OA (hydrocarbon like OA and biomass burning OA). The formation of OOA through fog processing is proved by the correlation of OOA concentration with hydroxyl methyl sulfonate signal and by the similarity of OOA spectra with organic mass spectra obtained by re-aerosolization of fog water samples. The oxygen to carbon ratio and the hydrogen to carbon ratio of

  1. Evaluation of trace elements contamination in cloud/fog water at an elevated mountain site in Northern China.

    PubMed

    Liu, Xiao-huan; Wai, Ka-ming; Wang, Yan; Zhou, Jie; Li, Peng-hui; Guo, Jia; Xu, Peng-ju; Wang, Wen-xing

    2012-07-01

    Totally 117 cloud/fog water samples were collected at the summit of Mt. Tai (1534m a.s.l.)-the highest mountain in the Northern China Plain. The results were investigated by a combination of techniques including back trajectory model, regional air quality and dust storm models, satellite observations and Principal Component Analysis. Elemental concentrations were determined by Inductively Coupled Plasma Mass Spectrometry, with stringent quality control measures. Higher elemental concentrations were found at Mt. Tai compared with those reported by other overseas studies. The larger proportions and higher concentrations of toxic elements such as Pb and As in cloud/fog water compared with those in rainwater at Mt. Tai suggests higher potential hazards of cloud/fog water as a source of contamination in polluted areas to the ecosystem. Peak concentrations of trace elements were frequently observed during the onset of cloud/fog events when liquid water contents of cloud/fog water were usually low and large amount of pollutants were accumulated in the ambient air. Inverse relationship between elemental concentrations and liquid water contents were only found in the samples with high electrical conductivities and liquid water contents lower than 0.3gm(-3). Affected mainly by the emissions of steel industries and mining activities, air masses transported from south/southwest of Mt. Tai were frequently associated with higher elemental concentrations. The element Mn is attributed to play an important role in the acidity of cloud/fog water. The composition of cloud/fog water influenced by an Asian dust storm event was reported, which was seldom found in the literature. PMID:22503636

  2. Evaluation of trace elements contamination in cloud/fog water at an elevated mountain site in Northern China.

    PubMed

    Liu, Xiao-huan; Wai, Ka-ming; Wang, Yan; Zhou, Jie; Li, Peng-hui; Guo, Jia; Xu, Peng-ju; Wang, Wen-xing

    2012-07-01

    Totally 117 cloud/fog water samples were collected at the summit of Mt. Tai (1534m a.s.l.)-the highest mountain in the Northern China Plain. The results were investigated by a combination of techniques including back trajectory model, regional air quality and dust storm models, satellite observations and Principal Component Analysis. Elemental concentrations were determined by Inductively Coupled Plasma Mass Spectrometry, with stringent quality control measures. Higher elemental concentrations were found at Mt. Tai compared with those reported by other overseas studies. The larger proportions and higher concentrations of toxic elements such as Pb and As in cloud/fog water compared with those in rainwater at Mt. Tai suggests higher potential hazards of cloud/fog water as a source of contamination in polluted areas to the ecosystem. Peak concentrations of trace elements were frequently observed during the onset of cloud/fog events when liquid water contents of cloud/fog water were usually low and large amount of pollutants were accumulated in the ambient air. Inverse relationship between elemental concentrations and liquid water contents were only found in the samples with high electrical conductivities and liquid water contents lower than 0.3gm(-3). Affected mainly by the emissions of steel industries and mining activities, air masses transported from south/southwest of Mt. Tai were frequently associated with higher elemental concentrations. The element Mn is attributed to play an important role in the acidity of cloud/fog water. The composition of cloud/fog water influenced by an Asian dust storm event was reported, which was seldom found in the literature.

  3. Fog as a fresh-water resource: overview and perspectives.

    PubMed

    Klemm, Otto; Schemenauer, Robert S; Lummerich, Anne; Cereceda, Pilar; Marzol, Victoria; Corell, David; van Heerden, Johan; Reinhard, Dirk; Gherezghiher, Tseggai; Olivier, Jana; Osses, Pablo; Sarsour, Jamal; Frost, Ernst; Estrela, María J; Valiente, José A; Fessehaye, Gebregiorgis Mussie

    2012-05-01

    The collection of fog water is a simple and sustainable technology to obtain fresh water for afforestation, gardening, and as a drinking water source for human and animal consumption. In regions where fresh water is sparse and fog frequently occurs, it is feasible to set up a passive mesh system for fog water collection. The mesh is directly exposed to the atmosphere, and the foggy air is pushed through the mesh by the wind. Fog droplets are deposited on the mesh, combine to form larger droplets, and run down passing into a storage tank. Fog water collection rates vary dramatically from site to site but yearly averages from 3 to 10 l m(-2) of mesh per day are typical of operational projects. The scope of this article is to review fog collection projects worldwide, to analyze factors of success, and to evaluate the prospects of this technology. PMID:22328161

  4. Fog as a fresh-water resource: overview and perspectives.

    PubMed

    Klemm, Otto; Schemenauer, Robert S; Lummerich, Anne; Cereceda, Pilar; Marzol, Victoria; Corell, David; van Heerden, Johan; Reinhard, Dirk; Gherezghiher, Tseggai; Olivier, Jana; Osses, Pablo; Sarsour, Jamal; Frost, Ernst; Estrela, María J; Valiente, José A; Fessehaye, Gebregiorgis Mussie

    2012-05-01

    The collection of fog water is a simple and sustainable technology to obtain fresh water for afforestation, gardening, and as a drinking water source for human and animal consumption. In regions where fresh water is sparse and fog frequently occurs, it is feasible to set up a passive mesh system for fog water collection. The mesh is directly exposed to the atmosphere, and the foggy air is pushed through the mesh by the wind. Fog droplets are deposited on the mesh, combine to form larger droplets, and run down passing into a storage tank. Fog water collection rates vary dramatically from site to site but yearly averages from 3 to 10 l m(-2) of mesh per day are typical of operational projects. The scope of this article is to review fog collection projects worldwide, to analyze factors of success, and to evaluate the prospects of this technology.

  5. Environmental fog/rain visual display system for aircraft simulators

    NASA Technical Reports Server (NTRS)

    Chase, W. D. (Inventor)

    1982-01-01

    An environmental fog/rain visual display system for aircraft simulators is described. The electronic elements of the system include a real time digital computer, a caligraphic color display which simulates landing lights of selective intensity, and a color television camera for producing a moving color display of the airport runway as depicted on a model terrain board. The mechanical simulation elements of the system include an environmental chamber which can produce natural fog, nonhomogeneous fog, rain and fog combined, or rain only. A pilot looking through the aircraft wind screen will look through the fog and/or rain generated in the environmental chamber onto a viewing screen with the simulated color image of the airport runway thereon, and observe a very real simulation of actual conditions of a runway as it would appear through actual fog and/or rain.

  6. A climatological study of fog in Japan based on event data

    NASA Astrophysics Data System (ADS)

    Akimoto, Yuko; Kusaka, Hiroyuki

    2015-01-01

    A climatological study is carried out to understand the characteristics of fog in Japan. This study uniquely focuses on fog density and fog type using atmospheric visibility data from surface observations. The main results are summarized below, within the following three contexts: 1) the characteristics of fog and dense fog, 2) fog type, and 3) long-term change in the number of foggy days. Most of the foggy and densely foggy regions in Japan are inland mountainous areas, basin areas, and the Pacific coast of eastern and northern Japan. Fog density varies seasonally. Although the warmer seasons have the highest frequency of fog occurrence in Japan, the density of fog tends to be higher in the colder seasons. Land cover also affects the density of fog. In the urban area, fog rarely forms, with dense mist sometimes forming. The most common type of fog in Japan is radiation fog, which accounts for half of all fog events. The dominant fog types of the inland areas, the Pacific coast, and the western part of Japan are radiation fog, advection fog and rain fog, respectively. The numbers of foggy days decrease at many of the observation sites during a 40-year period from 1966 to 2005. Inland and basin sites showed the largest decrease. Urban areas were once affected by fogs, but now experience mist instead. In contrast, most coastal sites showed no clear trend of decrease and some sites even showed an increase in the numbers of foggy days.

  7. The USRA workshop report: Electrostatic fog dispersal

    NASA Technical Reports Server (NTRS)

    Davis, M. H. (Editor)

    1983-01-01

    The Workshop was held at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, on February 1-2, 1983. The Workshop was attended by seventeen experts in the scientific fields of fog and cloud physics, charged-particle electrodynamics, atmospheric turbulence, atmospheric electricity, and electro-gasdynamics. The major objective of the Workshop was to assess the scientific merits and scientific basis of the proposed system and to assess its potential for operational application.

  8. The Pacific Coast Fog Project: A Multi-disciplinary Effort to Provide Web-based Climate Products for Ecologists

    NASA Astrophysics Data System (ADS)

    Torregrosa, A.; Combs, C.; Ellrod, G. P.; Faloona, I. C.; Gultepe, I.

    2012-12-01

    The Pacific Coast Fog Project is an effort to pool the expertise from multiple science disciplines to provide regional and local climate information on the frequency and character of fog for effective management of coastal California natural resources. Marine stratocumulus (fog) is a major modifier of the climatic condition along the Pacific coast and has significant effects on the hydrologic cycle and thermodynamic balance in coastal ecological, biological, and economic systems. For example fog is the major source of moisture during summer months for redwood forests, a treasured natural resource. Fog also modulates shallow stream temperatures to reduce the mortality rate of young salmon during their freshwater life stages and adults returning from the ocean to spawn. Fog induced cooling reduces summer energy costs along the Pacific Coast and reduces sun burn on crops such as grapes that are important to the local economy. Furthermore, disruptions in fog distribution or frequency resulting from future climate change would change evapotranspiration rates impacting California water supply and use. Coastal fog is a complex phenomenon with many measurable parameters including extent, frequency, and duration of cloud cover; cloud deck thickness, liquid water content, base height above land, density, heterogeneity, and thermal properties. Variations in fog are a result of processes acting at multiple scales across ocean-land-atmosphere boundaries. Factors that drive the occurrence, duration, and type of fog events along the coast include dynamics of atmospheric summertime inversions, synoptic weather patterns, ocean upwelling, topography, aerosol-cloud dynamics, and differences in temperature between inland valleys and the littoral ocean areas. Estimating the distribution, frequency and characteristics of coastal fog and stratus and evaluating the resulting ecosystem responses require a diverse array of measurements and models that link processes at multiple scales. The

  9. Sea Fog Forecasting with Lagrangian Models

    NASA Astrophysics Data System (ADS)

    Lewis, J. M.

    2014-12-01

    In 1913, G. I. Taylor introduced us to a Lagrangian view of sea fog formation. He conducted his study off the coast of Newfoundland in the aftermath of the Titanic disaster. We briefly review Taylor's classic work and then apply these same principles to a case of sea fog formation and dissipation off the coast of California. The resources used in this study consist of: 1) land-based surface and upper-air observations, 2) NDBC (National Data Buoy Center) observations from moored buoys equipped to measure dew point temperature as well as the standard surface observations at sea (wind, sea surface temperature, pressure, and air temperature), 3) satellite observations of cloud, and 4) a one-dimensional (vertically directed) boundary layer model that tracks with the surface air motion and makes use of sophisticated turbulence-radiation parameterizations. Results of the investigation indicate that delicate interplay and interaction between the radiation and turbulence processes makes accurate forecasts of sea fog onset unlikely in the near future. This pessimistic attitude stems from inadequacy of the existing network of observations and uncertainties in modeling dynamical processes within the boundary layer.

  10. Otoscope fogging: examination finding for perforated tympanic membrane

    PubMed Central

    Naylor, Jason F

    2014-01-01

    The author reports a recently recognised physical examination finding, otoscope fogging, for perforated tympanic membrane. Otoscope fogging is defined as condensation forming in the view field of the otoscope while inspecting the ear. In the setting of occult perforation secondary to the inability to visualise the entire tympanic membrane, otoscope fogging may provide the clinician with valuable information since medical management may differ if perforation is present. PMID:24879720

  11. Characterization of polycyclic aromatic hydrocarbons in fog-rain events.

    PubMed

    Li, Xiang; Li, Pengfei; Yan, Lili; Chen, Jianmin; Cheng, Tiantao; Xu, Shifen

    2011-11-01

    Atmospheric polycyclic aromatic hydrocarbons (PAHs) mainly originate from incomplete combustion or pyrolysis of materials containing carbon and hydrogen. They exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). Current studies in atmospheric PAHs are predominantly focused on fog and rainwater samples. Some sampling difficulties are associated with fog samples. This study presented the first observation of the characteristics of PAHs in fog samples using a solid phase microextraction (SPME) technique. Eighteen fog samples were collected during ten fog events from March to December 2009 in the Shanghai area. PAHs were extracted by SPME and analyzed by gas chromatography-mass spectrometry (GC-MS). As the compounds were partially soluble in water, with solubility decreasing with increasing molecular weight, low molecular weight (LMW) PAH compounds were universally found in the fog water samples. Naphthalene (NaP), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flo) were dominant compounds in fog water. The total PAH concentration in fog water ranged from 0.03 to 6.67 μg L(-1) (mean of 1.06 μg L(-1)), and was much higher in winter than in summer. The concentration of PAHs in fog or rain water decreased after undergoing a pre-rain or pre-fog wash. The average concentration of PAHs was higher in fog than in rain. Diagnostic ratio analysis suggested that petroleum and combustion were the dominant contributors to PAHs in urban Shanghai. Backward trajectories were calculated to determine the origin of the air masses, showing that air masses were mostly from the northeast territory.

  12. Efficient fog harvesting by Stipagrostis sabulicola (Namib dune bushman grass)

    NASA Astrophysics Data System (ADS)

    Roth-Nebelsick, A.; Ebner, M.; Miranda, T.

    2010-07-01

    Stipagrostis sabulicola is an endemic species of the central Namib Desert which settles on extremely arid dune fields. Due to its ability to persistence even during exceptionally dry years it is generally assumed that water supply of this species is substantially based on fog water. In this contribution, the results of a study investigating the capability of S. sabulicola for fog harvesting are presented. For this purpose, stem flow rates of S. sabulicola during fog events, spatial gradient of soil water content (SWC) close to mounds of S. sabulicola and its leaf water potential (LWP) before and after fog events were monitored together with climate parameters. According to the data obtained during this study, S. sabulicola is able to harvest substantial amounts of water by fog catchment from nocturnal fog events. Since culms of S. sabulicola are often stiff with an upright habitus, fog harvesting occurs via stemflow that conducts water directly towards the root zone of a plant. According to this mechanism, the stem runoff is concentrated within the area of the mound. A medium-sized mound of S. sabulicola is able to collect an amount of about 4 l per fog night. This fog harvesting leads to a considerable spatial gradient of soil water content with values decreasing with increasing distance from the mound. As a result of the water input by fog drip, SWC within the mound increases significantly, particularly close to the culm bases where SWC values increased to 2.2 % after a fog event. Due to the uneven distribution of water by stemflow, SWC within a mound shows high spatial heterogeneity which is also illustrated by the numerous outliers and extreme values of SWC within the mound region. This heterogeneity is also due to the fact that several sagging leaves are always present causing fog drip which more or less irregularly scatters moisture. For bare soil outside of a mound, the water content is not substantially increased, amounting to 0.78 % on average during dry

  13. The measurement of the size distribution of artificial fogs

    NASA Technical Reports Server (NTRS)

    Deepak, A.; Cliff, W. C.; Mcdonald, J. R.; Ozarski, R.; Thomson, J. A. L.; Huffaker, R. M.

    1974-01-01

    The size-distribution of the fog droplets at various fog particle concentrations in fog chamber was determined by two methods: (1) the Stokes' velocity photographic method and (2) using the active scattering particle spectrometer. It is shown that the two techniques are accurate in two different ranges of particle size - the former in the radii range (0.1 micrometers to 10.0 micrometers), and the latter for radii greater than 10.0 micrometers. This was particularly true for high particle concentration, low visibility fogs.

  14. Animal or plant: which is the better fog water collector?

    PubMed

    Nørgaard, Thomas; Ebner, Martin; Dacke, Marie

    2012-01-01

    Occasional fog is a critical water source utilised by plants and animals in the Namib Desert. Fog basking beetles (Onymacris unguicularis, Tenebrionidae) and Namib dune bushman grass (Stipagrostris sabulicola, Poaceae) collect water directly from the fog. While the beetles position themselves optimally for fog water collection on dune ridges, the grass occurs predominantly at the dune base where less fog water is available. Differences in the fog-water collecting abilities in animals and plants have never been addressed. Here we place beetles and grass side-by-side in a fog chamber and measure the amount of water they collect over time. Based on the accumulated amount of water over a two hour period, grass is the better fog collector. However, in contrast to the episodic cascading water run-off from the grass, the beetles obtain water in a steady flow from their elytra. This steady trickle from the beetles' elytra to their mouth could ensure that even short periods of fog basking--while exposed to predators--will yield water. Up to now there is no indication of specialised surface properties on the grass leafs, but the steady run-off from the beetles could point to specific property adaptations of their elytra surface.

  15. Near-explicit Gas-phase Chemistry Coupled with Extensive Aqueous Mechanism: Looking at Ethanol (E85) Exhaust in a Fog

    NASA Astrophysics Data System (ADS)

    Ginnebaugh, D. L.; Jacobson, M. Z.

    2011-12-01

    We combine a near-explicit gas-phase chemical mechanism with an extensive aqueous mechanism in a chemical solver to examine the effects of ethanol (E85) versus gasoline on the fate of pollutants in the presence of a fog. We use the Master Chemical Mechanism (MCM, version 3.1, Leeds University) and the Chemical Aqueous Phase Radical Mechanism, CAPRAM 3.0, with the SMVGEAR II chemical ordinary differential solver to provide the speed necessary to simulate complex chemistry. The MCM has over 13, 500 organic reactions and 4,600 species, while CAPRAM treats aqueous chemistry among 390 species and 829 reactions (including 51 gas-to-aqueous phase reactions). We validate a simplified version of the model against results from a comprehensive intercomparison by Barth et al (2003). In previous work on ethanol (E85), we analyzed the temperature-dependence of ethanol and gasoline exhaust chemistry and its impact on urban air pollution considering only gas-phase chemistry. In addition to the air pollution findings, we verified that using the MCM with SMVGEAR is practical in a 3-D model. Here, we extend our study to include aqueous chemistry in the presence of a fog. We investigate the impact aqueous reactions have on unburned ethanol and acetaldehyde mixing ratios in the atmosphere in particular because acetaldehyde is an ozone precursor and carcinogen, and aqueous oxidation has potential to speed the conversion of unburned ethanol to acetaldehyde. Acetaldehyde also forms acetic acid in aqueous solution. Acetic acid vapor is an eye, nose, and lung irritant, so both species contribute negatively to human health. We look at the impact of fog liquid water content and temperature on the degradation of emitted aromatic and other species as well, from both gasoline and E85.

  16. On the Influence of a Simple Microphysics Parametrization on Radiation Fog Modelling: A Case Study During ParisFog

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaojing; Musson-Genon, Luc; Dupont, Eric; Milliez, Maya; Carissimo, Bertrand

    2014-05-01

    A detailed numerical simulation of a radiation fog event with a single column model is presented, which takes into account recent developments in microphysical parametrizations. One-dimensional simulations are performed using the computational fluid dynamics model Code_Saturne and the results are compared to a very detailed in situ dataset collected during the ParisFog campaign, which took place near Paris, France, during the winter 2006-2007. Special attention is given to the detailed and complete diurnal simulations and to the role of microphysics in the fog life cycle. The comparison between the simulated and the observed visibility, in the single-column model case study, shows that the evolution of radiation fog is correctly simulated. Sensitivity simulations show that fog development and dissipation are sensitive to the droplet-size distribution through sedimentation/deposition processes but the aerosol number concentration in the coarse mode has a low impact on the time of fog formation.

  17. Effects of simulated acidic rain on one species each of Pseudoparmelia, Usunea, and umbilicaria

    SciTech Connect

    Sigal, L.L.; Johnston, J.W.

    1986-01-01

    The lichens Pseudoparmelia caperata (L.) Hale, Usnea of subfusca Stirt., and Umbilicaria mammulata (Ach.) Tuck. were exposed to simulated acidic rain with pH levels of 2.3, 3.0, 3.3, 4.3, or 5.6 and other ions in concentrations normally found in rain in the eastern United States. The pH levels of the most-acidic treatments (3.3, 3.0, 2.3) were similar to those found in fog, cloud water, and occasional rainfall events. The pH 4.3 and 5.6 treatments compared to average ambient conditions in the eastern and western United States, respectively, and caused no significant effects on photosynthesis. However, after the first week of treatment, significant effects of rain pH at the most-acidic treatments on gross photosynthesis were detected in P. caperata and U. mammulata, but not in U. of subfusca. Visible effects of injury were also observed and included bleaching, necrotic spots, and necrotic margins, which resembled damage seen in field populations of U. mammulata, the most-sensitive species.

  18. SO/sub 2/(g)-to-sulfate conversion rate in an oil-fired-power-plant plume in a fog bank

    SciTech Connect

    Eatough, D.J.; Arthur, R.J.; Eatough, N.L.; Hill, M.W.; Mangelson, N.F.; Richter, B.E.; Hansen, L.D.; Cooper, J.A.

    1983-01-01

    High acidity in rainfall, cloud droplets and fog droplets in areas influenced by anthropogenic sources of SO/sub 2/(g) and NO/sub x/(g) has been attributed to the formation of both H/sub 2/SO/sub 4/ and HNO/sub 3/. It has been suggested, based on the analysis of field data, that rapid conversion of SO/sub 2/(g) to sulfate must occur in cloud or fog droplets. Direct measurements of the rate of SO/sub 2/(g) to sulfate conversion in an oil-fired power plant plume as it passes through a fog bank are reported here. A conversion rate of 30+-4% SO/sub 2/(g) h/sup -1/ was found in the fog bank.

  19. The design of an optimal fog water collector: A theoretical analysis

    NASA Astrophysics Data System (ADS)

    Regalado, Carlos M.; Ritter, Axel

    2016-09-01

    We investigate the collection efficiency of different fog water catchers assemblies (mainly flat and cylindrical structures equipped with several screens of staggered filaments) by means of parametric equations which take into consideration both impaction and aerodynamic effects. We introduce different models that vary in complexity and range of applicability, and may be used to analyze the effect that geometry, number of screens, spacing and inclination of the filament strands have on the fog water yield of the collector. Increasing the number of impacting screens, nR, is shown to improve the collection efficiency up to an optimum for nR = 3-5; beyond nR > 5 impermeability to the airflow makes the fog catcher less efficient. Geometry of the collector is shown to be relatively important: unless wind direction varies widely, the rectangular flat design is preferred over the cylindrical one, because of its larger drag, i.e. increased aerodynamic efficiency, ηa. In fact ηa is shown to be limiting, such that values over ηa > 50% are difficult to attain. By contrast the impaction efficiency, ηimp, of fog water droplets onto multiple nR parallel screens of filaments may reach theoretical values of ηimp > 80%. Inclination of the impacting screens over the vertical may slightly reduce ηimp, but this may be compensated by a reduction in flow resistance, i.e. increased aerodynamic efficiency.

  20. Examination of the evolution of radiation and advection fogs. Final report

    SciTech Connect

    Orgill, M.M.

    1993-01-01

    A literature study was done on radiation and advection fog evolution. For radiation fog, six stages of fog evolution have been identified -- (1) precursor, (2) sunset, (3) conditioning, (4) mature, (5) sunrise, and (6) dissipation. The evolution of advection fog models has been in parallel with radiation fog models, but no identified stages in the evolution of advection fog have been proposed: (1) precursor, (2) initiation, (3) mature, and (4) dissipation. Radiation and advection fog models will require greater sophistication in order to study fog spatial and temporal variability. Physical aspects that require further study are discussed.

  1. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season.

    PubMed

    Zhang, Dalong; Zhang, Zhongdian; Li, Jianming; Chang, Yibo; Du, Qingjie; Pan, Tonghua

    2015-01-01

    The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L.) productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1) without environment control and (2) with a micro-fog system operating when the air vapor pressure deficit (VPD) of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR) of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR), and to a lesser extent caused by leaf area ratio (LAR). Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season. PMID:26221726

  2. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season.

    PubMed

    Zhang, Dalong; Zhang, Zhongdian; Li, Jianming; Chang, Yibo; Du, Qingjie; Pan, Tonghua

    2015-01-01

    The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L.) productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1) without environment control and (2) with a micro-fog system operating when the air vapor pressure deficit (VPD) of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR) of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR), and to a lesser extent caused by leaf area ratio (LAR). Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season.

  3. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season

    PubMed Central

    Zhang, Dalong; Zhang, Zhongdian; Li, Jianming; Chang, Yibo; Du, Qingjie; Pan, Tonghua

    2015-01-01

    The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L.) productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1) without environment control and (2) with a micro-fog system operating when the air vapor pressure deficit (VPD) of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR) of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR), and to a lesser extent caused by leaf area ratio (LAR). Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season. PMID:26221726

  4. Satellite-based multi-spectral detection of the Widespread and Persistent Winter Fog over the Indo-Gangetic Plains

    NASA Astrophysics Data System (ADS)

    Gautam, R.; Rizvi, S.

    2015-12-01

    The Indo-Gangetic Plains (IGP), in the northern parts of south Asia, are subjected to dense haze/fog during winter months, on an annual basis. The thick fog prevalent during December/January months is both persistent and widespread in nature, often covering the entire IGP which stretches over 1500km in length. This study used multi-spectral imagery from MODIS data, to develop algorithms for daytime as well as nighttime detection of fog during winter 2000 to 2014 over the IGP. Specifically, our nighttime detection algorithm employs a bispectral thresholding technique, involving brightness temperature difference (BTD) between two spectral channels- 3.9 and 11.02μm. The theoretical basis for the detection using the 3.9 μm and 11.02 μm channels rely on the particular emissive properties of the two channels for fog droplets (Bendix and Bachmann, 1991). The small droplets found in fog are less emissive at 3.9 μm than at 11.02 μm. Brightness temperatures computed from corresponding radiance data (MODIS Level-1B) of band 22 (3.9 μm) and band 31 (11.02 μm), in conjunction with theoretical calculations from a radiative transfer (RT) model, were utilized to evaluate threshold value of BTD. Using theoretical RT calculations and automated analysis of hundreds of moderately high resolution satellite imagery (pixel resolution of 1km), our threshold cutoff for foggy pixels results in BTD value of 4 (deg) K. Additionally, to minimize contamination, we apply a spatial variability filter to discriminate the uniform texture of fog from other low-level clouds. A similar methodology based on BTD is also tested for daytime fog detection and separation from other cloud types. Furthermore, on the basis of operational multispectral retrievals of cloud properties (cloud effective radius, cloud top pressure, and cloud fraction) from MODIS, we have also processed spatial occurrences of fog climatology from 2000 to 2014. To validate our satellite retrieval algorithm of fog detection from

  5. The miR-17-92 cluster regulates FOG-2 expression and inhibits proliferation of mouse embryonic cardiomyocytes.

    PubMed

    Xiang, Rui; Lei, Han; Chen, Mianzhi; Li, Qinwei; Sun, Huan; Ai, Jianzhong; Chen, Tielin; Wang, Honglian; Fang, Yin; Zhou, Qin

    2012-02-01

    MicroRNAs (miRNAs) have gradually been recognized as regulators of embryonic development; however, relatively few miRNAs have been identified that regulate cardiac development. A series of recent papers have established an essential role for the miRNA-17-92 (miR-17-92) cluster of miRNAs in the development of the heart. Previous research has shown that the Friend of Gata-2 (FOG-2) is critical for cardiac development. To investigate the possibility that the miR-17-92 cluster regulates FOG-2 expression and inhibits proliferation in mouse embryonic cardiomyocytes we initially used bioinformatics to analyze 3' untranslated regions (3'UTR) of FOG-2 to predict the potential of miR-17-92 to target it. We used luciferase assays to demonstrate that miR-17-5p and miR-20a of miR-17-92 interact with the predicted target sites in the 3'UTR of FOG-2. Furthermore, RT-PCR and Western blot were used to demonstrate the post-transcriptional regulation of FOG-2 by miR-17-92 in embryonic cardiomyocytes from E12.5-day pregnant C57BL/6J mice. Finally, EdU cell assays together with the FOG-2 rescue strategy were employed to evaluate the effect of proliferation on embryonic cardiomyocytes. We first found that the miR-17-5p and miR-20a of miR-17-92 directly target the 3'UTR of FOG-2 and post-transcriptionally repress the expression of FOG-2. Moreover, our findings demonstrated that over-expression of miR-17-92 may inhibit cell proliferation via post-transcriptional repression of FOG-2 in embryonic cardiomyocytes. These results indicate that the miR-17-92 cluster regulates the expression of FOG-2 protein and suggest that the miR-17-92 cluster might play an important role in heart development.

  6. Gene conversion and DNA sequence polymorphism in the sex-determination gene fog-2 and its paralog ftr-1 in Caenorhabditis elegans.

    PubMed

    Rane, Hallie S; Smith, Jessica M; Bergthorsson, Ulfar; Katju, Vaishali

    2010-07-01

    Gene conversion, a form of concerted evolution, bears enormous potential to shape the trajectory of sequence and functional divergence of gene paralogs subsequent to duplication events. fog-2, a sex-determination gene unique to Caenorhabditis elegans and implicated in the origin of hermaphroditism in this species, resulted from the duplication of ftr-1, an upstream gene of unknown function. Synonymous sequence divergence in regions of fog-2 and ftr-1 (excluding recent gene conversion tracts) suggests that the duplication occurred 46 million generations ago. Gene conversion between fog-2 and ftr-1 was previously discovered in experimental fog-2 knockout lines of C. elegans, whereby hermaphroditism was restored in mutant obligately outcrossing male-female populations. We analyzed DNA-sequence variation in fog-2 and ftr-1 within 40 isolates of C. elegans from diverse geographic locations in order to evaluate the contribution of gene conversion to genetic variation in the two gene paralogs. The analysis shows that gene conversion contributes significantly to DNA-sequence diversity in fog-2 and ftr-1 (22% and 34%, respectively) and may have the potential to alter sexual phenotypes in natural populations. A radical amino acid change in a conserved region of the F-box domain of fog-2 was found in natural isolates of C. elegans with significantly lower fecundity. We hypothesize that the lowered fecundity is due to reduced masculinization and less sperm production and that amino acid replacement substitutions and gene conversion in fog-2 may contribute significantly to variation in the degree of inbreeding and outcrossing in natural populations.

  7. Understanding Acid Rain

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  8. Simulating Atmospheric Free-Space Optical Propagation; Part II: Haze, Fog, and Low Clouds Attenuations

    NASA Astrophysics Data System (ADS)

    Achour, Maha

    2002-12-01

    One of the biggest challenges facing Free-Space Optics deployment is proper understanding of optical signal propagation in different atmospheric conditions. In an earlier study by the author (30), attenuation by rain was analyzed and successfully modeled for infrared signal transmission. In this paper, we focus on attenuation due to scattering by haze, fog and low clouds droplets using the original Mie Scattering theory. Relying on published experimental results on infrared propagation, electromagnetic waves scattering by spherical droplet, atmospheric physics and thermodynamics, UlmTech developed a computer-based platform, Simulight, which simulates infrared signal (750 nm-12 μm) propagation in haze, fog, low clouds, rain and clear weather. Optical signals are scattered by fog droplets during transmission in the forward direction preventing the receiver from detecting the minimum required power. Weather databases describe foggy conditions by measuring the visibility parameter, which is, in general, defined as the maximum distance that the visible 550 nm signal can travel while distinguishing between the target object and its background at 2% contrast. Extrapolating optical signal attenuations beyond 550 nm using only visibility is not as straightforward as stated by the Kruse equation which is unfortunately widely used. We conclude that it is essential to understand atmospheric droplet sizes and their distributions based on measured attenuations to effectively estimate infrared attenuation. We focus on three types of popular fogs: Evolving, Stable and Selective.

  9. Gprk2 adjusts Fog signaling to organize cell movements in Drosophila gastrulation.

    PubMed

    Fuse, Naoyuki; Yu, Fengwei; Hirose, Susumu

    2013-10-01

    Gastrulation of Drosophila melanogaster proceeds through sequential cell movements: ventral mesodermal (VM) cells are induced by secreted Fog protein to constrict their apical surfaces to form the ventral furrow, and subsequently lateral mesodermal (LM) cells involute toward the furrow. How these cell movements are organized remains elusive. Here, we observed that LM cells extended apical protrusions and then underwent accelerated involution movement, confirming that VM and LM cells display distinct cell morphologies and movements. In a mutant for the GPCR kinase Gprk2, apical constriction was expanded to all mesodermal cells and the involution movement was abolished. In addition, the mesodermal cells halted apical constriction prematurely in accordance with the aberrant accumulation of Myosin II. Epistasis analyses revealed that the Gprk2 mutant phenotypes were dependent on the fog gene. Overexpression of Gprk2 suppressed the effects of excess Cta, a downstream component of Fog signaling. Based on these findings, we propose that Gprk2 attenuates and tunes Fog-Cta signaling to prevent apical constriction in LM cells and to support appropriate apical constriction in VM cells. Thus, the two distinct cell movements in mesoderm invagination are not predetermined, but rather are organized by the adjustment of cell signaling.

  10. O'Neill's Kurzdrama "Fog" im Englischunterricht (O'Neill's Short Drama "Fog" in English Teaching)

    ERIC Educational Resources Information Center

    Wolter, Juergen

    1977-01-01

    O'Neill's "Fog" is recommended as a discussion-stimulating work for English (as a second language) classes in grades 11-13. The content is discussed from an instructional point of view. Teaching goals are considered. Experiences with the play in grade 11 are described, and methodological hints are given. (Text is in German.) (IFS/WGA)

  11. Analysis of Dynamical and Thermal Processes Driving Fog and Quasi-Fog Life Cycles Using the 2010-2013 ParisFog Dataset

    NASA Astrophysics Data System (ADS)

    Dupont, J. C.; Haeffelin, M.; Stolaki, S.; Elias, T.

    2016-04-01

    The data from suite of in situ sensors, passive and active remote sensing instruments dedicated to document simultaneously radiative and thermo-dynamical processes driving the fog life cycle at the SIRTA Observatory (instrumented site for atmospheric remote sensing research) near Paris during two periods of 6 months are analysed. The study focuses on the analysis of the relative role of key physical processes and their interactions during fog formation, development and dissipation phases. This work presents, from analysis of detailed observations, the range of values that critical parameters have to take for fog and quasi-fog formation. In our study, we consider fog (horizontal visibility lower than 1 km, a dataset of 300 h) and quasi-fog (horizontal visibility ranging from 1 to 2 km, a dataset of 400 h) events induced by radiative cooling (53 events) and stratus lowering (64 events). For the radiative fog events, (with radiative cooling during prefog conditions), we note that the longwave net radiative flux (around -60 ± 5 W/m2) induces a cooling of the surface layer. The vertical structure of this cooling is controlled by dynamics, that is, wind shear and horizontal and vertical velocities. In case of very low mixing (wind speed below 0.6 m/s), the thermal stability is very strong with a temperature inversion around 3.5 °C for 10 m and a humidity gradient reaching 10 % preventing vertical development of the fog layer. For stratus-lowering fog events, the altitude of the stratus layer, the vertical mixing and the absolute value of humidity are driving parameters of the fog formation. Our statistical analysis shows that a stratus cloud with a cloud base around 170 m and with a small cloud-base subsidence rate of 50 m/h leads to fog, whereas a stratus cloud with a base around 800 m agl, with a larger cloud-base subsidence rate of 190 m/h conducts to quasi-fog situations with an important increase of the stratus liquid water path.

  12. Fog chemical composition and its feedback to fog water fluxes, water vapor fluxes, and microphysical evolution of two events near Paris

    NASA Astrophysics Data System (ADS)

    Degefie, D. T.; El-Madany, T.-S.; Held, M.; Hejkal, J.; Hammer, E.; Dupont, J.-C.; Haeffelin, M.; Fleischer, E.; Klemm, O.

    2015-10-01

    The chemical composition of collected fog water and its temporal evolution was studied during the PARISFOG campaign in winter 2012/2013 at the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphéric) atmospheric observatory outside Paris, France. A further development of the caltech active fog collector was applied, in which the collected fog water gets into contact with Teflon and polyether ether ketone (PEEK) material exclusively. The collector was operational whenever the visibility was below 1000 m. In addition, the turbulent and gravitational fluxes of fog water and water vapor flux were used to examine in detail the temporal evolution the chemical composition of two fogs. The technique was applied to two fog events, one representing a radiation fog and the other one representing a stratus lowering fog. The result revealed that the dominant inorganic species in the fog water were NH4+, NO3-, Ca2 + and SO42 -, which accounted for more than 85% of the ion balance. The pH ranged from 3.7 to 6.2. In the evolution the two fog events, the interaction among the turbulent fog water flux, gravitational fog water flux and water vapor flux controlled the major ion loads (amount of ions, dissolved in fog droplets per volume of air) and ion concentrations (amount dissolved per volume of liquid water) of the fog water. In the radiation fog event, an increase of ion loads and ion concentrations occurred when the direction of water vapor flux towards to the place where the condensation process occurred. A decrease of ion loads and ion concentrations mainly happened by gravitational fog water flux with a minor contribution from turbulent fog water flux. However, when the turbulent water vapor flux was oriented downward, it turned the turbulent fog water flux upward and offset the removal of ions in the fog. In the stratus lowering fog event, the turbulent fog water flux and the gravitational water flux together mainly contributed to the fog water deposition and

  13. Fogging technique used to coat magnesium with plastic

    NASA Technical Reports Server (NTRS)

    Mroz, T. S.

    1967-01-01

    Cleaning process and a fogging technique facilitate the application of a plastic coating to magnesium plates. The cleaning process removes general organic and inorganic surface impurities, oils and greases, and oxides and carbonates from the magnesium surfaces. The fogging technique produces a thin-filmlike coating in a clean room atmosphere.

  14. Scavenging of black carbon in Chilean coastal fogs.

    PubMed

    Heintzenberg, Jost; Cereceda-Balic, Francisco; Vidal, Victor; Leck, Caroline

    2016-01-15

    In November/December 2013 a pilot experiment on aerosol/fog interaction was conducted on a coastal hill in the suburbs of Valparaíso, Chile. Passages of garúa fog were monitored with continuous recordings of a soot photometer and an optical aerosol spectrometer. An optical fog sensor and an automatic weather station provided meteorological data with which the aerosol could be classified. High-resolution back trajectories added meteorological information. From filter samples, optical and chemical aerosol information was derived. Scavenging coefficients of black carbon (BC) and measured particulate mass below 1 μm diameter (PM1) were estimated with three approaches. Averaging over all fog periods of the campaign yielded a scavenging coefficient of only 6% for BC and 40% for PM1. Dividing the data into four 90°-wind sectors gave scavenging factors for BC ranging from 13% over the Valparaíso, Viña del Mar conurbation to 50% in the marine sector (180°-270°). The third, and independent approach was achieved with two pairs of chemical aerosol samples taken inside and outside fogs, which yielded a scavenging coefficient of 25% for BC and 70% for nonseasalt sulfate. Whereas fogs occurred rather infrequently in the beginning of the campaign highly regular daily fog cycles appeared towards the end of the experiment, which allowed the calculation of typical diurnal cycles of the aerosol in relation to a fog passage. PMID:26410708

  15. 7. Keeper's house, fog signal house and light tower, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Keeper's house, fog signal house and light tower, view north northeast, west and south sides of keeper's house and tower, southwest and southeast sides of fog signal house - West Quoddy Head Light Station, At eastern tip of West Quaddy Head, Lubec, Washington County, ME

  16. 12. Fuel house and fog signal house, view northeast, southwest ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Fuel house and fog signal house, view northeast, southwest side of fuel house, west and south sides of fog signal house - Cape Elizabeth Light Station, Near Two Lights State Park at end of Two Lights Road, off State Highway 77, Cape Elizabeth, Cumberland County, ME

  17. Clearing the Fog from the Undergraduate Course in Linear Algebra

    ERIC Educational Resources Information Center

    Scott, Damon

    2007-01-01

    For over a decade it has been a common observation that a "fog" passes over the course in linear algebra once abstract vector spaces are presented. See [2, 3]. We show how this fog may be cleared by having the students translate "abstract" vector-space problems to isomorphic "concrete" settings, solve the "concrete" problem either by hand or with…

  18. Fog, plant leaves and deposition of droplets

    NASA Astrophysics Data System (ADS)

    Konrad, W.; Ebner, M.; Traiser, C.; Roth-Nebelsick, A.

    2010-07-01

    For various plants and animals, the accumulation of fog or dew droplets constitutes an essential part of their water supply. Understanding how water droplets deposited by fog or dew events interact with plant or animal surfaces is essential for gaining insight into the functionality of these surfaces. Besides being interesting within the realm of biology, this knowledge is indispensable for technical applications. Frequently, it is advantageous to know (i) the growth rate of a droplet attached by surface tension to a surface which grows due to a given influx of fog particles, (ii) the maximum volume and (iii) the "lifespan" of a droplet before it detaches from the surface or starts to slide down along the plant surface, driven by gravity. Starting from principles of physics, we calculate quantitative expressions addressing questions (i) to (iii) for droplets which are attached to surfaces characterised by a high degree of symmetry, such as horizontally oriented or inclined planes, sections of spheres, cones and rotationally symmetric crevices. Furthermore, we treat the behaviour of droplets attached to a surface of non-constant contact angle. Although real surfaces never meet their geometric idealisations, results based on these often represent suitable and useful approximations to reality. Finally, we apply our results to Stipagrostis sabulicola, a dune grass of the Namib desert which satisfies its water demand solely by capturing fog and dew droplets. Pictures taken with a scanning electron microscope show that the stem of S. sabulicola is longitudinally built up by alternating elevated and countersunk strips. Filling gaps in the experimental observation with theoretical speculation, the following picture emerges: Assuming that the elevated strips exhibit a higher contact angle than the countersunk strips, water droplets being deposited on the elevated strips are drawn towards the latter. The lower contact angle which prevails there increases the droplets

  19. Pesticide occurrence and distribution in fog collected near Monterey, California

    SciTech Connect

    Schomburg, C.J.; Glotfelty, D.E. ); Seiber, J.N. )

    1991-01-01

    The authors analyzed pesticides in air and fog in several fog events sampled near Monterey, CA, to determine whether the uptake of pesticides in advected oceanic fog was different from uptake in fog forming under stagnant inversion conditions in California's Central Valley in the winter. Data for several pesticides common to both ares showed that the pesticide content and distribution were remarkable similar in the two locations. The conversion of organophosphorus insecticides to their corresponding oxons, and aqueous-phase enrichment factors, were also very similar. Evidence is presented to support the hypothesis that enhanced pesticide concentration in fogwater is caused by strongly sorptive nonfilterable particles and colloids in the fog liquid that are derived from atmospheric particles.

  20. Effects of inhaled acids on lung biochemistry

    SciTech Connect

    Last, J.A.

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  1. Effects of inhaled acids on lung biochemistry.

    PubMed

    Last, J A

    1989-02-01

    Effects of respirable aerosols of sulfuric acid, ammonium sulfate, sodium sulfite, and ammonium persulfate on lungs of rats are reviewed. The literature regarding interactions between ozone or nitrogen dioxide and acidic aerosols (ammonium sulfate, sulfuric acid) is discussed. An unexpected interaction between nitrogen dioxide and sodium chloride aerosol is also discussed. An attempt is made to identify bases for prediction of how and when acid aerosols might potentiate effects of inhaled gases.

  2. Caught in the thickness of brain fog: exploring the cognitive symptoms of Chronic Fatigue Syndrome.

    PubMed

    Ocon, Anthony J

    2013-01-01

    Chronic Fatigue Syndrome (CFS) is defined as greater than 6 months of persistent fatigue that is experienced physically and cognitively. The cognitive symptoms are generally thought to be a mild cognitive impairment, but individuals with CFS subjectively describe them as "brain fog." The impairment is not fully understood and often is described as slow thinking, difficulty focusing, confusion, lack of concentration, forgetfulness, or a haziness in thought processes. Causes of "brain fog" and mild cognitive impairment have been investigated. Possible physiological correlates may be due to the effects of chronic orthostatic intolerance (OI) in the form of the Postural Tachycardia Syndrome (POTS) and decreases in cerebral blood flow (CBF). In addition, fMRI studies suggest that individuals with CFS may require increased cortical and subcortical brain activation to complete difficult mental tasks. Furthermore, neurocognitive testing in CFS has demonstrated deficits in speed and efficiency of information processing, attention, concentration, and working memory. The cognitive impairments are then perceived as an exaggerated mental fatigue. As a whole, this is experienced by those with CFS as "brain fog" and may be viewed as the interaction of physiological, cognitive, and perceptual factors. Thus, the cognitive symptoms of CFS may be due to altered CBF activation and regulation that are exacerbated by a stressor, such as orthostasis or a difficult mental task, resulting in the decreased ability to readily process information, which is then perceived as fatiguing and experienced as "brain fog." Future research looks to further explore these interactions, how they produce cognitive impairments, and explain the perception of "brain fog" from a mechanistic standpoint.

  3. Severe haze episodes and seriously polluted fog water in Ji'nan, China.

    PubMed

    Wang, Xinfeng; Chen, Jianmin; Sun, Jianfeng; Li, Weijun; Yang, Lingxiao; Wen, Liang; Wang, Wenxing; Wang, Xinming; Collett, Jeffrey L; Shi, Yang; Zhang, Qingzhu; Hu, Jingtian; Yao, Lan; Zhu, Yanhong; Sui, Xiao; Sun, Xiaomin; Mellouki, Abdelwahid

    2014-09-15

    Haze episodes often hit urban cities in China recently. Here, we present several continuous haze episodes with extremely high PM2.5 levels that occurred over several weeks in early 2013 and extended across most parts of the northern and eastern China-far exceeding the Beijing-Tianjin-Hebei region. Particularly, the haze episode covered ~1 million km(2) on January 14, 2013 and the daily averaged PM2.5 concentration exceeded 360 μg m(-3) in Ji'nan. The observed maximum hourly PM2.5 concentration in urban Ji'nan reached 701 μg m(-3) at 7:00 am (local time) in January 30. During these haze episodes, several fog events happened and the concurrent fog water was found to be seriously polluted. For the fog water collected in Ji'nan from 10:00 pm in January 14 to 11:00 am in January 15, sulfate, nitrate, and ammonium were the major ions with concentrations of 1.54 × 10(6), 8.98 × 10(5), and 1.75 × 10(6) μeq L(-1), respectively, leading to a low in-situ pH of 3.30. The sulfate content in the fog sample was more than 544 times as high as those observed in other areas. With examination of the simultaneously observed data on PM2.5 and its chemical composition, the fog played a role in scavenging and removing fine particles from the atmosphere during haze episodes and thus was seriously contaminated. However, the effect was not sufficient to obviously cleanse air pollution and block haze episodes.

  4. Leaching of cell wall components caused by acid deposition on fir needles and trees.

    PubMed

    Shigihara, Ado; Matsumoto, Kiyoshi; Sakurai, Naoki; Igawa, Manabu

    2008-07-15

    Virgin fir forests have been declining since the 1960s at Mt. Oyama, which is located at the eastern edge of the Tanzawa Mountains and adjacent to the Kanto plain in Japan. An acid fog frequently occurs in the mountains. We collected throughfall and stemflow under fir trees and rainfall every week during January-December 2004 at Mt. Oyama to clarify the influence of acid fog on the decline of fir (Abies firma) needles. In relation to throughfall and stemflow, D-mannose, D-galactose, and D-glucose are the major neutral sugar components; only D-glucose is a major component of rainfall. The correlation coefficient between the total neutral sugars and uronic acid (as D-galacturonic acid), which is a key component of the cross-linking between pectic polysaccharides, was high except for rainfall. The leached amount of calcium ion, neutral sugars, uronic acid, and boron is related to the nitrate ion concentration in throughfall. Results of a laboratory exposure experiment using artificial fog water simulating the average composition of fog water observed at Mt. Oyama (simulated acid fog: SAF) on the fir seedling needles also shows a large leaching of these components from the cell walls of fir needles. The leaching amount increased concomitantly with decreasing pH of the SAF solution. We also observed that a dimeric rhamnogalacturonan II-borate complex (dRG-II-B) that exists in the cell wall as pectic polysaccharide was converted to monomeric RG-II (mRG-II) by the leaching of calcium ion and boron. Results not only of field observations but also those of laboratory experiments indicate a large effect of acid depositions on fir needles.

  5. On the water-soluble organic nitrogen concentration and mass size distribution during the fog season in the Po Valley, Italy.

    PubMed

    Montero-Martínez, Guillermo; Rinaldi, Matteo; Gilardoni, Stefania; Giulianelli, Lara; Paglione, Marco; Decesari, Stefano; Fuzzi, Sandro; Facchini, Maria Cristina

    2014-07-01

    The study of organic nitrogen gained importance in recent decades due to its links with acid rain, pollution, and eutrophication. In this study, aerosol and fog water samples collected from two sites in Italy during November 2011 were analyzed to characterize their organic nitrogen content. Organic nitrogen contributed 19-25% of the total soluble nitrogen in the aerosol and around 13% in fog water. The largest water soluble organic nitrogen concentrations in the PM1.2 fraction occurred during the diurnal period with mean values of 2.03 and 2.16 μg-N m(-3) (154 and 145 nmol-N m(-3)) at Bologna and San Pietro Capofiume (SPC), respectively. The mean PM10 WSON concentration during diurnal periods at SPC was 2.30 μg-N m(-3) (164 nmol-N m(-3)) while it was 1.34 and 0.82 μg-N m(-3) (95.7 and 58.5 nmol-N m(-3)) in the night and fog water samples, respectively. Aerosol mass distribution profiles obtained during fog changed significantly with respect to those estimated in periods without fog periods due to fog scavenging, which proved to be over 80% efficient. Linear correlations suggested secondary processes related to combustion and, to a lesser extent, biomass burning, as plausible sources of WSON. Regarding the inorganic nitrogen fraction, the results showed that ammonium was the largest soluble inorganic nitrogen component in the samples.

  6. Preliminary results of the PreViBOSS project: description of the fog life cycle by ground-based and satellite observation

    NASA Astrophysics Data System (ADS)

    Elias, Thierry; Jolivet, Dominique; Dupont, Jean-Charles; Haeffelin, Martial; Burnet, Frédéric

    2012-11-01

    The instrument set-up designed by the PreViBOSS project for the ParisFog field campaign is suitable to sound microphysical properties of droplets and interstitial aerosols during developed fog in a semi-urban environment. Developed fog is defined as LWC < 7 mg m-3 and the temperature vertical gradient over 30 m, ΔT, smaller than 0.04 K/m. Visibility averaged over November 2011 is 385+/-340 m (with rare values larger than 1000 m), and month average of LWC is 60+/-60 mg m-3. The droplet effective radius decreases from 14 to 4 μm when the number concentration increases from less than 10 to 220 cm-3. Particle extinction coefficient is computed by Mie theory applied on size distribution observed during developed fog in ambient conditions by both PALAS WELAS and DMT FM100. Comparison with particle extinction coefficient directly measured by the Degreanne DF20 visibilimeter demonstrates satisfying agreement, within combined uncertainties. Ratio of computed over measured particle extinction coefficient is 1.15+/-0.35. Visibility smaller than 1000 m at 3 m above ground level is observed not only during developed fog but also during shallow fog, which presents a significant vertical gradient, as ΔT > 0.4 K/m. In this case, LWC is highly variable and may be observed below 7 mg m-3. The consequent month average of LWC is 30+/-80 mg m-3. The optical counters miss large droplets significantly contributing to extinction in shallow fogs. Consequently, it is not possible to reproduce with satisfaction the particle extinction coefficient in shallow fog. Fog type may be distinguished by association of groundbased visibilimeter and MSG/SEVIRI. When clear-sky is given by EUMETSAT/NWCSAF cloud type product while visibility is observed smaller than 1000 m at SIRTA, in 75% cases a shallow fog occurs, and in other cases, horizontal heterogeneity characterises the developed fog within the SIRTA pixel, as during the dissipation phase. Moreover, consistently, low and very low clouds are

  7. Size resolved fog water chemistry and its atmospheric implications

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida; Ervens, Barbara; Bhattu, Deepika

    2015-04-01

    Fog is a natural meteorological phenomenon that occurs throughout the world. It usually contains substantial quantity of liquid water and results in severe visibility reduction leading to disruption of normal life. Fog is generally seen as a natural cleansing agent but it also has the potential to form Secondary Organic Aerosol (SOA) via aqueous processing of ambient aerosols. Size- resolved fog water chemistry for inorganics were reported in previous studies but processing of organics inside the fog water and quantification of aqSOA remained a challenge. To assess the organics processing via fog aqueous processing, size resolved fog water samples were collected in two consecutive winter seasons (2012-13, 2013-14) at Kanpur, a heavily polluted urban area of India. Caltech 3 stage fog collector was used to collect the fog droplets in 3 size fraction; coarse (droplet diameter > 22 µm), medium (22> droplet diameter >16 µm) and fine (16> droplet diameter >4 µm). Collected samples were atomized into various instruments such as Aerosol Mass Spectrometer (AMS), Cloud Condensation Nucleus Counter (CCNc), Total Organic Carbon (TOC) and a thermo denuder (TD) for the physico-chemical characterization of soluble constituents. Fine droplets are found to be more enriched with different aerosol species and interestingly contain more aged and less volatile organics compared to other coarser sizes. Organics inside fine droplets have an average O/C = 0.87 compared to O/C of 0.67 and 0.74 of coarse and medium droplets. Metal chemistry and higher residence time of fine droplets are seemed to be the two most likely reasons for this outcome from as the results of a comprehensive modeling carried out on the observed data indicate. CCN activities of the aerosols from fine droplets are also much higher than that of coarse or medium droplets. Fine droplets also contain light absorbing material as was obvious from their 'yellowish' solution. Source apportionment of fog water organics via

  8. [Observational study of formaldehyde in air, rain and fog water at a site on the Mangdang Mountain of Fujian, China].

    PubMed

    Wang, Xiao-yan; Wang, Hui-xiang; Ma, Yi-yuan

    2010-08-01

    Through 2,4-dinitrophenylhydrazine (DNPH) high-performance liquid chromatography (HPLC) method, the levels of formaldehyde in ambient air, rain and fog samples were measured in Mangdang Mountain, Fujian Province, from March to April 2009. The average concentrations of formaldehyde in ambient air, rain and fog are 4.0 x 10(-10), 2.19 micromol/L and 2.94 micromol/L, respectively. Based on previous researches, this study described formaldehyde hydrolysis and reacting with S(IV) and other chemical reaction processes in liquid phase, explaining the phenomenon that the solubility of formaldehyde in the liquid phase is higher than the theoretical value. On-site measured Henry coefficients (Hme) and the effective Henry coefficients (H*) were derived from concentration of formaldehyde in ambient air, rain and fog samples and references. Comparing Hme and H*, this study found that the measured liquid phase concentrations of formaldehyde are higher than the theoretical concentrations, consistent with the references. The further founding is that Hme/H* in fog is higher than in rain, proving the result of Mangdang Mountain that the concentration of formaldehyde in fog is higher than in rain. Considering the climatic characteristics of Mangdang Mountain in spring, the wet deposition of formaldehyde is an important way in this area.

  9. A field investigation and numerical simulation of coastal fog

    NASA Technical Reports Server (NTRS)

    Mack, E. J.; Eadie, W. J.; Rogers, C. W.; Kocmond, W. C.; Pilie, R. J.

    1973-01-01

    A field investigation of the microphysical and micrometeorological features of fogs occurring near Los Angeles and Vandenberg, California was conducted. Observations of wind speed and direction, temperature, dew point, vertical wind velocity, dew deposition, drop-size distribution, liquid water content, and haze and cloud nucleus concentration were obtained. These observations were initiated in late evening prior to fog formation and continued until the time of dissipation in both advection and radiation fogs. Data were also acquired in one valley fog and several dense haze situations. The behavior of these parameters prior to and during fog are discussed in detail. A two-dimensional numerical model was developed to investigate the formation and dissipation of advection fogs under the influence of horizontal variations in surface temperature. The model predicts the evolution of potential temperature, water vapor content, and liquid water content in a vertical plane as determined by vertical turbulent transfer and horizontal advection. Results are discussed from preliminary numerical experiments on the formation of warm-air advection fog and dissipation by natural and artificial heating from the surface.

  10. Optimal design of permeable fiber network structures for fog harvesting.

    PubMed

    Park, Kyoo-Chul; Chhatre, Shreerang S; Srinivasan, Siddarth; Cohen, Robert E; McKinley, Gareth H

    2013-10-29

    Fog represents a large untapped source of potable water, especially in arid climates. Numerous plants and animals use textural and chemical features on their surfaces to harvest this precious resource. In this work, we investigate the influence of the surface wettability characteristics, length scale, and weave density on the fog-harvesting capability of woven meshes. We develop a combined hydrodynamic and surface wettability model to predict the overall fog-collection efficiency of the meshes and cast the findings in the form of a design chart. Two limiting surface wettability constraints govern the re-entrainment of collected droplets and clogging of mesh openings. Appropriate tuning of the wetting characteristics of the surfaces, reducing the wire radii, and optimizing the wire spacing all lead to more efficient fog collection. We use a family of coated meshes with a directed stream of fog droplets to simulate a natural foggy environment and demonstrate a five-fold enhancement in the fog-collecting efficiency of a conventional polyolefin mesh. The design rules developed in this work can be applied to select a mesh surface with optimal topography and wetting characteristics to harvest enhanced water fluxes over a wide range of natural convected fog environments.

  11. Coastal Upwelling and Deep Fog: 50-year Worldwide Climatology

    NASA Astrophysics Data System (ADS)

    Koracin, D. R.

    2015-12-01

    An analysis is presented of the marine fog distribution based upon the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) ship observations taken during 1950-2007. Deep fog occurrence is reported in routine weather reports that are encoded in an ICOADS ship observation. Occurrence is estimated by the number of deep fog observations divided by the total present weather observations in a one-degree area centered on latitude and longitude grid point intersections. The mean fog occurrence for the summer (June-July-August) 1950-2007 was computed for each one degree point for the world. There are five major world locations with coastal SST minimums due to wind driven upwelling. Four of these are during the local summer on the eastern side of a semi-permanent anticyclone on eastern sides of northern and southern mid-latitudes of the Pacifica and the Atlantic. The fifth is during the SW monsoon in the Indian Ocean. For all five of these locations, the deep fog occurrence is at maximum during the upwelling season, with the greatest occurrences concentrated along the coast and isolated over the SST minimum. For the five coastal fog maxima, the greatest and longest duration occurrence along coast occurrence is associated with the coldest sea surface temperature and longest along coast occurrence, which is along N. California- S. Oregon. In contrast, the lowest occurrence of fog and the least along coast occurrence is associated with the warmest sea surface temperatures and least along coast occurrence along the SE Arabian Peninsula. The remaining three zones, Peru-Chile, NW Africa, and SW Africa are between the two extremes in fog occurrence, along coast coverage and sea surface temperature. Peru-Chile is more complex than the others as the Peru upwelling and fog appears the more dominant although ship observations are sparse along Chile.

  12. New method for evaluating high-quality fog protective coatings

    NASA Astrophysics Data System (ADS)

    Czeremuszkin, Grzegorz; Latreche, Mohamed; Mendoza-Suarez, Guillermo

    2011-05-01

    Fogging is commonly observed when humid-warm air contacts the cold surface of a transparent substrate, i.e. eyewear lenses, making the observed image blurred and hazy. To protect from fogging, the lens inner surfaces are protected with Anti-Fog coatings, which render them hydrophilic and induce water vapor condensation as a smooth, thin and invisible film, which uniformly flows down on the lens as the condensation progresses. Coatings differ in protection level, aging kinetics, and susceptibility to contamination. Some perform acceptably in limited conditions, beyond which the condensing water film becomes unstable, nonuniform, and scatters light or shows refractory distortions, both affecting the observed image. Quantifying the performance of Anti-Fog coated lenses is difficult: they may not show classical fogging and the existing testing methods, based on fog detection, are therefore inapplicable. The presented method for evaluating and quantifying AF properties is based on characterizing light scattering on lenses exposed to controlled humidity and temperature. Changes in intensity of laser light scattered at low angles (1, 2 4 and 8 degrees), observed during condensation of water on lenses, provide information on the swelling of Anti-Fog coatings, formation of uniform water film, going from an unstable to a steady state, and on the coalescence of discontinuous films. Real time observations/measurements allow for better understanding of factors controlling fogging and fog preventing phenomena. The method is especially useful in the development of new coatings for military-, sport-, and industrial protective eyewear as well as for medical and automotive applications. It allows for differentiating between coatings showing acceptable, good, and excellent performance.

  13. Partitioning the relative contribution of dew and fog to total occult precipitation across a decreasing fog inundation gradient in the Pajaro Valley, CA

    NASA Astrophysics Data System (ADS)

    Farlin, J. P.; Paw U, K. T.

    2015-12-01

    Traditionally, occult precipitation has been difficult to measure, especially given that it can take two predominant forms: fogs and dews. Recent studies have shown that estimates of fog deposition can be made using constructed fog collectors of various styles. Leaf-wetness sensors have also been deployed to try and estimate the relative wetness of leaves during fog events, but coastal systems can integrate both fog deposition and dew condensation, which cannot be differentiated with such sensors alone. We measured fog interception with Decagon Leaf Wetness Sensors (LWSs) outfitted with a 1m2 mesh passive fog collector in areas adjacent to the California Irrigation Management Information System (CIMIS) sites in the Pajaro Valley. The LWSs that were deployed were covered with a partial shield or left uncovered. Covering the LWS creates a microclimate that allows discrimination between fog events that horizontally advect droplets that impact individual leaves, and dew events, which condense once dew point temperature is reached. By measuring fog with a standard measurement device (mesh fog collector), and comparing it to LWSs that have either fog exposure or fog exclusion (covered LWSs), we can partition the relative contribution of dew to overall occult precipitation. This would be the first study quantifying the amount of water inputs (horizontally advecting fog) to the amount of recycled water (dew) to gain a greater understanding of the role of occult precipitation in catchment water balances across coastal California.

  14. Using Coastal Fog to Support Sustainable Water Use in a California Agricultural System

    NASA Astrophysics Data System (ADS)

    Baguskas, S. A.; Loik, M. E.

    2015-12-01

    Impacts of climate change threaten California farmers in a number of ways, most importantly through a decline in freshwater availability, concurrent with a rise in water demand. The future of California's multibillion-dollar agricultural industry depends on increasing water use efficiency on farms. In coastal California, the growing season of economically important crops overlaps with the occurrence of coastal fog, which buffers the summer dry season through shading effects and direct water inputs. While the impacts of coastal fog on plant biology have been extensively studied in natural ecosystems, very few studies have evaluated its direct effects on the water and energy budgets of agricultural systems. The objective of this study was to develop a mechanistic understanding of the relationships between coastal fog and the water and energy budgets of croplands in order to improve estimates of crop-scale evapotranspiration rates, which has potential to curtail groundwater use based on local cloud meteorology. We established three sites on strawberry farms along a coastal-inland gradient in the Salinas Valley, California. At each site, we installed a passive fog collector and a micrometeorological station to monitor variation in microclimate conditions. Flow meters were installed in drip lines to quantify irrigation amount and timing. To assess plant response to foggy and non-foggy conditions, we collected measurements of photosynthesis and transpiration rates at the leaf and canopy-scale between June-September 2015. We found that canopy-level transpiration rates on foggy days were reduced by half compared to sunny, clear days (1.5 and 3 mmol H2O m-2 s-1, respectively). Whereas the amount of direct fog water inputs to the soil did not differ significantly between foggy and clear days, average photosynthetically active radiation between 0900-1100 hr. was reduced from 1500 to 500 μmol photons m-2 s-1 between these sampling periods. Our results provide convincing

  15. Numerical simulation of advection fog formation on multi-disperse aerosols due to combustion-related pollutants

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Liaw, G. S.

    1980-01-01

    The effects of multi-disperse distribution of the aerosol population are presented. Single component and multi-component aerosol species on the condensation/nucleation processes which affect the reduction in visibility are described. The aerosol population with a high particle concentration provided more favorable conditions for the formation of a denser fog than the aerosol population with a greater particle size distribution when the value of the mass concentration of the aerosols was kept constant. The results were used as numerical predictions of fog formation. Two dimensional observations in horizontal and vertical coordinates, together with time-dependent measurements were needed as initial values for the following physical parameters: (1)wind profiles; (2) temperature profiles; (3) humidity profiles; (4) mass concentration of aerosol particles; (5) particle size distribution of aerosols; and (6) chemical composition of aerosols. Formation and dissipation of advection fog, thus, can be forecasted numerically by introducing initial values obtained from the observations.

  16. Uric Acid and Antioxidant Effects of Wine

    PubMed Central

    Boban, Mladen; Modun, Darko

    2010-01-01

    The aim of this article is to review the role of uric acid in the context of antioxidant effects of wine and its potential implication to human health. We described and discussed the mechanisms of increase in plasma antioxidant capacity after consumption of moderate amounts of wine. Because this effect is largely contributed by acute elevation in plasma uric acid, we paid special attention to wine constituents and metabolic processes that are likely to be involved in uric acid elevation. PMID:20162741

  17. Star Family Seen Through Dusty Fog

    NASA Astrophysics Data System (ADS)

    2007-03-01

    Images made with ESO's New Technology Telescope at La Silla by a team of German astronomers reveal a rich circular cluster of stars in the inner parts of our Galaxy. Located 30,000 light-years away, this previously unknown closely-packed group of about 100,000 stars is most likely a new globular cluster. Star clusters provide us with unique laboratory conditions to investigate various aspects of astrophysics. They represent groups of stars with similar ages, chemical element abundances and distances. Globular clusters, in particular, are fossils in the Milky Way that provide useful information. With ages of about 10 billion years, they are among the oldest objects in our Galaxy - almost as old as the Universe itself. These massive, spherical shaped star clusters are therefore witnesses of the early, mysterious ages of the Universe. ESO PR Photo 12/07 ESO PR Photo 12/07 The Newly Identified Cluster "Moreover, the properties of globular clusters are deeply connected with the history of their host galaxy," says Dirk Froebrich from the University of Kent, and lead-author of the paper presenting the results. "We believe today that galaxy collisions, galaxy cannibalism, as well as galaxy mergers leave their imprint in the globular cluster population of any given galaxy. Thus, when investigating globular clusters we hope to be able to use them as an acid test for our understanding of the formation and evolution of galaxies," he adds. In our own Galaxy about 150 globular clusters are known, each containing many hundreds of thousands of stars. In contrast to their smaller and less regularly shaped siblings - open clusters - globular clusters are not concentrated in the galactic disc; rather they are spherically distributed in the galactic halo, with increasing concentration towards the centre of the Galaxy. Until the mid 1990s, globular clusters were identified mostly by eye - from visual inspection of photographic plates. However, these early searches are likely to have

  18. Fog scavenging of organic and inorganic aerosol in the Po Valley

    NASA Astrophysics Data System (ADS)

    Gilardoni, S.; Massoli, P.; Giulianelli, L.; Rinaldi, M.; Paglione, M.; Pollini, F.; Lanconelli, C.; Poluzzi, V.; Carbone, S.; Hillamo, R.; Russell, L. M.; Facchini, M. C.; Fuzzi, S.

    2014-07-01

    The interaction of aerosol with atmospheric water affects the processing and wet removal of atmospheric particles. Understanding such interaction is mandatory to improve model description of aerosol lifetime and ageing. We analyzed the aerosol-water interaction at high relative humidity during fog events in the Po Valley within the framework of the Agenzia Regionale per la Prevenzione e l'Ambiente (ARPA) - Emilia Romagna supersite project. For the first time in this area, the changes in particle chemical composition caused by fog are discussed along with changes in particle microphysics. During the experiment, 14 fog events were observed. The average mass scavenging efficiency was 70% for nitrate, 68% for ammonium, 61% for sulfate, 50% for organics, and 39% for black carbon. After fog formation, the interstitial aerosol was dominated by particles smaller than 200 nm Dva (vacuum aerodynamic diameter) and enriched in carbonaceous aerosol, mainly black carbon and water-insoluble organic aerosol. For each fog event, the size-segregated scavenging efficiency of nitrate and organic aerosol (OA) was calculated by comparing chemical species size distribution before and after fog formation. For both nitrate and OA, the size-segregated scavenging efficiency followed a sigmoidal curve, with values close to zero below 100 nm Dva and close to 1 above 700 nm Dva. OA was able to affect scavenging efficiency of nitrate in particles smaller than 300 nm Dva. A linear correlation between nitrate scavenging and particle hygroscopicity (κ) was observed, indicating that 44-51% of the variability of nitrate scavenging in smaller particles (below 300 nm Dva) was explained by changes in particle chemical composition. The size-segregated scavenging curves of OA followed those of nitrate, suggesting that organic scavenging was controlled by mixing with water-soluble species. In particular, functional group composition and OA elemental analysis indicated that more oxidized OA was scavenged

  19. 3. Light tower and fog signal house, view northeast, west ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Light tower and fog signal house, view northeast, west and south sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

  20. 11. Fog signal tower, view southeast, northwest and southwest sides ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Fog signal tower, view southeast, northwest and southwest sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  1. 28. Photograph of interior view of fog horn signal building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Photograph of interior view of fog horn signal building with two lighthouse keepers by steam engine wheel, ca. 1920. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

  2. 2. Oil house, fog signal house and light tower, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Oil house, fog signal house and light tower, view southwest, east and north sides - Great Duck Island Light Station, At southern tip of Great Duck Island southeast of Bass Harbor & northeast of Frenchboro, Frenchboro, Hancock County, ME

  3. 11. Fog signal house, view northnorthwest, east and south sides ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Fog signal house, view north-northwest, east and south sides - Cape Elizabeth Light Station, Near Two Lights State Park at end of Two Lights Road, off State Highway 77, Cape Elizabeth, Cumberland County, ME

  4. Fog Collection and Sustainable Architecture in Atacama Coast

    NASA Astrophysics Data System (ADS)

    Suau, C.

    2010-07-01

    It is imperative to integrate renewable energy and climate into zero-carbon buildings in arid lands, particularly when it is reinforced by natural and social science-based innovation in natural and built environs. The aim is twofold: On one hand, to establish potential natural and urban habitats and their yields required in different scales of intervention and, on another hand, augment rate and yield of fog collection used for drinking and irrigation in chosen locations. The purpose of this study is to integrate zero-carbon energy, landscape and sustainable architecture as a whole and thus envision potential inhabitation through self-sufficient space-frame configurations along the coast of Tarapacá Region in Chile. In a sequential way, this study distinguishes three scales of interventions: A. Territorial scale. It consists of rural and natural zones along the shore of Tarapacá Region: Fog oases, creeks or corridors. The strategic allocation of large fog collectors can bring local agriculture back and thus stop rural emigration; and also repair existing fragile ecosystems in several fog oases by harvesting and distributing mainly crop water. B. Local scale. The space-frame fog collectors are allocated in Alto Patache (fog oasis) and Iquique city (low-income sprawl of Alto Hospicio). These artefacts can supply both water and electricity to small communities through forestation, sustainable micro-agriculture and complementary electrification. C. Domestic scale. It consists of the design of autonomous housing configuration based in polygonal space-frames. This inhabitable unit is modular, deployable and lightweight; with an adjustable polyvalent membrane which performs as water repellent skin (facing South and SW winds) and shading device facing Equator. In addition, a domestic wind turbine is installed within the structural frame to provide autonomous electrification. Water collector, filtering (purification) and irrigation network is designed with available

  5. PLAM - a meteorological pollution index for air quality and its applications in fog-haze forecasts in North China

    NASA Astrophysics Data System (ADS)

    Yang, Y. Q.; Wang, J. Z.; Gong, S. L.; Zhang, X. Y.; Wang, H.; Wang, Y. Q.; Wang, J.; Li, D.; Guo, J. P.

    2016-02-01

    Using surface meteorological observation and high-resolution emission data, this paper discusses the application of the PLAM/h index (Parameter Linking Air-quality to Meteorological conditions/haze) in the prediction of large-scale low visibility and fog-haze events. Based on the two-dimensional probability density function diagnosis model for emissions, the study extends the diagnosis and prediction of the meteorological pollution index PLAM to the regional visibility fog-haze intensity. The results show that combining the influence of regular meteorological conditions and emission factors together in the PLAM/h parameterization scheme is very effective in improving the diagnostic identification ability of the fog-haze weather in North China. The determination coefficients for four seasons (spring, summer, autumn, and winter) between PLAM/h and visibility observation are 0.76, 0.80, 0.96, and 0.86, respectively, and all of their significance levels exceed 0.001, showing the ability of PLAM/h to predict the seasonal changes and differences of fog-haze weather in the North China region. The high-value correlation zones are located in Jing-Jin-Ji (Beijing, Tianjin, Hebei), Bohai Bay rim, and southern Hebei-northern Henan, indicating that the PLAM/h index is related to the distribution of frequent heavy fog-haze weather in North China and the distribution of emission high-value zone. Through comparative analysis of the heavy fog-haze events and large-scale clear-weather processes in winter and summer, it is found that PLAM/h index 24 h forecast is highly correlated with the visibility observation. Therefore, the PLAM/h index has good capability in identification, analysis, and forecasting.

  6. Interannual increase of regional haze-fog in North China Plain in summer by intensified easterly winds and orographic forcing

    NASA Astrophysics Data System (ADS)

    Cao, Ziqi; Sheng, Lifang; Liu, Qian; Yao, Xiaohong; Wang, Wencai

    2015-12-01

    Regional haze-fog events over the North China Plain (NCP) have attracted much attention in recent years. Their increase has been attributed to anthropogenic emissions of air pollutants and synoptic weather conditions. We investigated the influence of local meteorological conditions and large-scale circulation on the haze-fog events over the NCP during 2001-2012, and found a significant interannual increase in the number of summer regional haze-fog days. Analysis indicated that local meteorological conditions could partly explain the increase but failed to explain the spatial variation; meanwhile, regional circulation change induced by large-scale circulation and orographic forcing unveiled a possible spatiotemporal variation mechanism. In summer, the prevalent southerly winds over the NCP were obstructed by the Taihang and Yanshan mountains, steadying the outflow direction to the southeast, while different inflow direction controlled by large-scale circulation had different effects on regional circulation. In weak (strong) East Asian summer monsoon years, an intensified eastward (westward) zonal inflow wind component reinforced (weakened) the negative vorticity and formed an anomalous anticyclone (cyclone), which strengthened (weakened) the downward motion, so the dissipation capability was weakened (strengthened) and the wind speed decreased (increased), ultimately resulting in the increased (decreased) occurrence of haze-fog. We also found that the circulation anomaly had a good relationship with strong El Niño and La Niña events. There was more haze-fog over the NCP in the summers that followed a La Niña event, and less in summers that followed an El Niño event. This suggested the possibility that summer haze-fog phenomena could be predicted based on the phase of ENSO.

  7. Vertical profile of fog microphysics : a case study

    NASA Astrophysics Data System (ADS)

    Burnet, Frédéric; Brilouet, Pierre-Etienne; Mazoyer, Marie; Bourrianne, Thierry; Etcheberry, Jean-Michel; Gaillard, Brigitte; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Barrau, Sébastien; Defoy, Stephan

    2016-04-01

    The occurrence and development of fogs result from the non-linear interaction of competing radiative, thermodynamic, microphysical and dynamical processes and the forecasting of their life cycle still remains a challenging issue. Several field campaigns have been carried out at the SIRTA observatory in the Paris suburb area (France). These experiments have shown that fog events exhibit large differences of the microphysical properties and various evolutions during their life cycle. To better understand relationships between the different processes and to validate numerical simulations it is necessary however to document the vertical profile of the fog microphysics. A CDP (Cloud Droplet Spectrometer) from DMT (Droplet Measurement Technology, Boulder, CO) has been modified to allow measurements of the droplet size distribution in fog layers with a tethered balloon. This instrumental set-up has been used during a field campaign during the winter 2013-214 in the Landes area in the South West of France. To validate the vertical profiles provided by the modified CDP, a mast was equipped with microphysical instruments at 2 altitude levels with an another CDP at 24 m and a Fog Monitor FM100 at 42 m. The instrumental set-up deployed during this campaign is presented. Data collected during a fog event that occurred during the night of 5-6 March 2014 are analysed. We show that microphysical properties such as droplet number concentration, LWC and mean droplet size, exhibit different time evolution during the fog life cycle depending on the altitude level. Droplet size distribution measurements are also investigated. They reveal sharp variations along the vertical close to the top of the fog layer. In addition it is shown that the shape of the size distributions at the top follows a time evolution typical of a quasi-adiabatic droplet growth.

  8. Relationship between optical extinction and liquid water content in fogs

    NASA Astrophysics Data System (ADS)

    Klein, C.; Dabas, A.

    2014-05-01

    Studies carried out in the late 1970s suggest that a simple linear relationship exists in practice between the optical extinction in the thermal IR and the liquid water content (LWC) in fogs. Such a relationship opens the possibility to monitor the vertical profile of the LWC in fogs with a rather simple backscatter lidar. Little is known on how the LWC varies as a function of height and during the fog life cycle, so the new measurement technique would help understand fog physics and provide valuable data for improving the quality of fog forecasts. In this paper, the validity of the linear relationship is revisited in the light of recent observations of fog droplet size distributions measured with a combination of sensors covering a large range of droplet radii. In particular, large droplets (radius above 15 μm) are now detected, which was not the case in the late 1970s. The results confirm that the linear relationship still holds, at least for the mostly radiative fogs observed during the campaign. The impact of the precise value of the real and imaginary parts of the refractive index on the coefficient of the linear relationship is also studied. The usual practice considers that droplets are made of pure water. This assumption is probably valid for big drops, but it may be questioned for small ones since droplets are formed from condensation nuclei of highly variable chemical composition. The study suggests that the precise nature of condensation nuclei will primarily affect rather light fogs with small droplets and light liquid water contents.

  9. Inhalation toxicology of fog-oil obscurant. Final report, October 1981-February 1986

    SciTech Connect

    Grose, E.C.; Selgrade, M.J.; Davies, D.W.; Stead, A.J.

    1986-12-01

    Sixty-day-old, male and female rats were exposed by inhalation to fog-oil smoke. Mortality, LC50, subacute, and subchronic studies were performed. Mortality studies showed fog-oil smoke to be 100% lethal at 11.0 mg/L, 95% lethal at 5.0 mg/L, 20% lethal at 1.0 mg/L, and 0% lethal at 0.1 mg/L after a 6-hour exposure. The observed LC50 of fog-oil smoke after a 3.5-hr exposure was 5.2 mg/L. In the subacute and subchronic studies, rats were exposed to air, 0.2-, 0.5-, or 1.5-mg/L fog oil smoke for 3.5 hr/day, 4 days/wk for either 4 of 13 wk. Both pulmonary and systemic effects were investigated one day after the exposure ceased. For one 13-wk exposure group, animals were also examined 4 wk after the exposure. Following the subacute 4-exposure to 1.5 mg/L, a multifocal pneumonitis was observed. Lung lavage had an elevated number of polymorphonuclear leukoctes (PMNs), alveolar macrophages, and lung weights was observed after exposure to 0.5 mg/L. Pulmonary-function tests revealed an increase in end expiratory volume (EEV) after 1.5mg/L. Systemic effects after the subacute exposure were minimal. A decrease in zoxazolamine-induced paralysis time was observed following both 0.5 and 1.5 mg/L; however, no effect on pentobarbital-induced sleeping time was observed. Behavioral studies were negative, as were clinical chemistries and immune function tests.

  10. A field study of pollutant deposition in radiation fog

    SciTech Connect

    Waldman, J.M.; Jacob, D.J.; Munger, J.W.; Hoffman, M.R.

    1986-04-01

    Deposition during fog episodes can make a significant contribution to the overall flux of pollutants in certain ecosystems. Furthermore, when atmospheric stagnation prevents normal ventilation in a region, fog deposition may become the main route of pollutant removal. Fogs can consequently exert dominant control over pollutant levels in certain atmospheres. The southern San Joaquin Valley (SJV) of California is a region prone to wintertime episodes of atmospheric stagnation. These lead to elevated pollutant concentrations and/or dense, widespread fogs. Major oil-recovery operations plus widespread agricultural and livestock feeding activities are important sources of SO/sub 2/, NO/sub X/ and NH/sub 3/ in the valley. A multifaceted program of field monitoring was conducted in the SJV during the winter 1984-1985, focusing on aspects of pollutant scavenging and removal in the fog-laden atmosphere. Concentrations of major species were measured in gas, dry aerosol and fogwater phases. In addition, depositional fluxes were monitored by surrogate-surface methods. These measurements were employed to directly assess the magnitude of removal enhancement by fog.

  11. Distribution and long-term trends in various fog types over South Korea

    NASA Astrophysics Data System (ADS)

    Belorid, Miloslav; Lee, Chong Bum; Kim, Jea-Chul; Cheon, Tae-Hun

    2015-11-01

    This study analyzed the spatial and temporal distributions of various fog types over South Korea. Six types of fogs were identified using a classification algorithm based on simple conceptual models of fog formation. The algorithm was applied to a 25-year record of meteorological observations. The most common fog types were radiation fog, prevailing at inland stations, and precipitation fog at coastal and island stations. Declining temporal trends in the frequency of fog events ranging between 2.1 and 10.9 fog events per decade were found at eight inland and two coastal stations. Long-term trends for each fog type show that the decrease in the frequency of fog events is mainly due to a decrease in the frequency of radiation fogs ranging between 1.1 and 8.5 fog events per decade. To identify the potential factors related to the decrease in radiation fog events, the temporal trends in annual mean nocturnal maximal cooling rates and annual mean nocturnal specific humidity during nights with clear sky and clam winds were examined. The results show that the decrease in the frequency of radiation fog events is associated mainly with the pattern of urbanization occurring during the past two decades.

  12. Numerical forecasting of radiation fog. Part II: A comparison of model simulation with several observed fog events

    SciTech Connect

    Guedalia, D.; Bergot, T. )

    1994-06-01

    A 1D model adapted for forecasting the formation and development of fog, and forced with mesoscale parameters derived from a 3D limited-area model, was used to simulate three fog event observations made during the Lille 88 campaign. The model simulation correctly reproduced the time of fog formation and its vertical development when forcing terms derived from observations were used. It determined the influence of different physical processes and in particular that of dew deposition. The initial conditions deduced from the 3D model proved to be correct in two of the three events. On the other hand, the prediction of advection terms necessary for forecasting the vertical growth of fog was a more delicate matter. 15 refs., 21 figs.

  13. Climatology Study of Low-level Cloud and Fog in Mountain Terrain Using Satellite Observations and Modeling

    NASA Astrophysics Data System (ADS)

    Duan, Yajuan; Barros, Ana P.

    2015-04-01

    The presence of orographic clouds and fog has major environmental and economic implications that the potential shift in the space-time distribution can effectively redistribute freshwater resources and threaten the sustainability of the ecology, geomorphology and hydrology of mountainous regions and adjacent basins. This includes the Southern Appalachian Mountains, which rely closely on the moisture input from fog, cap clouds and light rainfall, as well as cloud forests in the Andes with frequent occurrence of dense fog. However, the applicability of fog forecasting models becomes limited in regions of complex terrain. The motivation of this project is to develop a satellite-based hydroclimatology and physical parameterization of orographic low-level clouds and fog regimes in the Southern Appalachians using a general methodology that can be applied to mountainous regions elsewhere. An algorithm for the detection and extraction of stratus clouds and fog was developed using cloud base height product from 8-years of CALIPSO and CloudSat observations, and evaluated against ground-based measurements from ceilometers. This population of low-level clouds and fog will be analyzed with GOES infrared and visible imagery, MODIS products, and with airport cloud height and visibility records to expand the spatial coverage beyond narrow satellite sensor swaths. The climatology will be further developed through integration with results from WRF high-solution simulations for selected periods since the bulk of the PMM network has been in place (2008-present) to aid in defining meteorological and time-of-day constraints in the interpretation of simulated satellite profiles through a satellite-sensor simulator. A 4-day WRF simulation is performed at Pegion Basin in the Southern Appalachian Mountains with increasing horizontal (0.25 km grid spacing) and vertical (up to 80 sigma levels) resolution and evaluated against observations collected during the Integrated Precipitation and

  14. Using hourly measurements to explore the role of secondary inorganic aerosol in PM2.5 during haze and fog in Hangzhou, China

    NASA Astrophysics Data System (ADS)

    Jansen, Roeland Cornelis; Shi, Yang; Chen, Jianmin; Hu, YunJie; Xu, Chang; Hong, Shengmao; Li, Jiao; Zhang, Min

    2014-11-01

    This paper explores the role of the secondary inorganic aerosol (SIA) species ammonium, NH{4/+}, nitrate, NO{3/-}, and sulfate, SO{4/2-}, during haze and fog events using hourly mass concentrations of PM2.5 measured at a suburban site in Hangzhou, China. A total of 546 samples were collected between 1 April and 8 May 2012. The samples were analyzed and classified as clear, haze or fog depending on visibility and relative humidity (RH). The contribution of SIA species to PM2.5 mass increased to ˜50% during haze and fog. The mass contribution of nitrate to PM2.5 increased from 11% during clear to 20% during haze episodes. Nitrate mass exceeded sulfate mass during haze, while near equal concentrations were observed during fog episodes. The role of RH on the correlation between concentrations of SIA and visibility was examined, with optimal correlation at 60%-70% RH. The total acidity during clear, haze and fog periods was 42.38, 48.38 and 45.51 nmol m-3, respectively, indicating that sulfate, nitrate and chloride were not neutralized by ammonium during any period. The nitrate to sulfate molar ratio, as a function of the ammonium to sulfate molar ratio, indicated that nitrate formation during fog started at a higher ammonium to sulfate molar ratio compared to clear and haze periods. During haze and fog, the nitrate oxidation ratio increased by a factor of 1.6-1.7, while the sulfur oxidation ratio increased by a factor of 1.2-1.5, indicating that both gaseous NO2 and SO2 were involved in the reduced visibility.

  15. Dissolved organic carbon (DOC) and select aldehydes in cloud and fog water: the role of the aqueous phase in impacting trace gas budgets

    NASA Astrophysics Data System (ADS)

    Ervens, B.; Wang, Y.; Eagar, J.; Leaitch, W. R.; Macdonald, A. M.; Valsaraj, K. T.; Herckes, P.

    2013-05-01

    Cloud and fog droplets efficiently scavenge and process water-soluble compounds and, thus, modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC) in the aqueous phase reach concentrations on the order of ~ 10 mgC L-1 which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i) the removal of species from the gas phase preventing their processing by gas phase reactions (e.g., photolysis of aldehydes) and (ii) the formation of unique products that do not have any efficient gas phase sources (e.g., dicarboxylic acids). We present measurements of DOC and select aldehydes in fog water at high elevation and intercepted clouds at a biogenically-impacted location (Whistler, Canada) and in fog water in a more polluted area (Davis, CA). Concentrations of formaldehyde, glyoxal and methylglyoxal were in the micromolar range and comprised ≤ 2% each individually of the DOC. Comparison of the DOC and aldehyde concentrations to those at other locations shows good agreement and reveals highest levels for both in anthropogenically impacted regions. Based on this overview, we conclude that the fraction of organic carbon (dissolved and insoluble inclusions) in the aqueous phase of clouds or fogs, respectively, comprises 2-~ 40% of total organic carbon. Higher values are observed to be associated with aged air masses where organics are expected to be more highly oxidised and, thus, more soluble. Accordingly, the aqueous/gas partitioning ratio expressed here as an effective Henry's law constant for DOC (KH*DOC) increases by an order of magnitude from 7 × 103 M atm-1 to 7 × 104 M atm-1 during the ageing of air masses. The measurements are accompanied by photochemical box model simulations. These simulations are used to contrast two

  16. Background on health effects of acid aerosols.

    PubMed

    Lippmann, M

    1989-02-01

    This introduction to the 1987 NIEHS-EPA Symposium on the Health Effects of Acid Aerosols reviews the state of our knowledge on this topic as of the close of the 1984 NIEHS Conference on the Health Effects of Acid Precipitation (Environmental Health Perspectives, Volume 63) and the results of some key studies completed since that time. These studies, together with the results of the studies presented in the papers that follow, provide a substantial increment in our knowledge of the health effects of acid aerosols.

  17. Background on health effects of acid aerosols.

    PubMed Central

    Lippmann, M

    1989-01-01

    This introduction to the 1987 NIEHS-EPA Symposium on the Health Effects of Acid Aerosols reviews the state of our knowledge on this topic as of the close of the 1984 NIEHS Conference on the Health Effects of Acid Precipitation (Environmental Health Perspectives, Volume 63) and the results of some key studies completed since that time. These studies, together with the results of the studies presented in the papers that follow, provide a substantial increment in our knowledge of the health effects of acid aerosols. PMID:2707208

  18. Fungal spores as potential ice nuclei in fog/cloud water and snow

    NASA Astrophysics Data System (ADS)

    Bauer, Heidi; Goncalves, Fabio L. T.; Schueller, Elisabeth; Puxbaum, Hans

    2010-05-01

    INTRODUCTION: In discussions about climate change and precipitation frequency biological ice nucleation has become an issue. While bacterial ice nucleation (IN) is already well characterized and even utilized in industrial processes such as the production of artificial snow or to improve freezing processes in food industry, less is known about the IN potential of fungal spores which are also ubiquitous in the atmosphere. A recent study performed at a mountain top in the Rocky Mountains suggests that fungal spores and/or pollen might play a role in increased IN abundance during periods of cloud cover (Bowers et al. 2009). In the present work concentrations of fungal spores in fog/cloud water and snow were determined. EXPERIMENTAL: Fog samples were taken with an active fog sampler in 2008 in a traffic dominated area and in a national park in São Paulo, Brazil. The number concentrations of fungal spores were determined by microscopic by direct enumeration by epifluorescence microscopy after staining with SYBR Gold nucleic acid gel stain (Bauer et al. 2008). RESULTS: In the fog water collected in the polluted area at a junction of two highly frequented highways around 22,000 fungal spores mL-1 were counted. Fog in the national park contained 35,000 spores mL-1. These results were compared with cloud water and snow samples from Mt. Rax, situated at the eastern rim of the Austrian Alps. Clouds contained on average 5,900 fungal spores mL-1 cloud water (1,300 - 11,000) or 2,200 spores m-3 (304 - 5,000). In freshly fallen snow spore concentrations were lower than in cloud water, around 1,000 fungal spores mL-1 were counted (Bauer et al. 2002). In both sets of samples representatives of the ice nucleating genus Fusarium could be observed. REFERENCES: Bauer, H., Kasper-Giebl, A., Löflund, M., Giebl, H., Hitzenberger, R., Zibuschka, F., Puxbaum, H. (2002). The contribution of bacteria and fungal spores to the organic carbon content of cloud water, precipitation and aerosols

  19. Pollution Levels in Fog at the Chilean Coast

    NASA Astrophysics Data System (ADS)

    Sträter, E.; Klemm, O.; Westbeld, A.

    2010-07-01

    During July and August 2008 fog water was collected for chemical analysis in Patache, at the coast of northern Chile, 60 km south of Iquique (20°49’S, 70°09’W). Advective fog events occur regularly at the cliff in the coastal range at about 800 m above MSL. People collect these types of fog water at some places along the coast with Large Fog Collectors (LFC) for domestic use and for watering field crops. So far, no chemical analysis of fog water was performed in Patache. Pure fogwater samples (38 samples from 8 fog events) were taken by using a passive Scientific Cylindrical Fog Collector. Major ions and trace metals were quantified. The analyses indicate very high ionic concentrations (mean 3500 µeq/l) and very low pH values (mean 3.3). The mean H+-concentration represents 16 % of the total ionic equivalent concentration. Sulfate is the anion exhibiting the highest concentrations. A mean value of 880 µeq/l was found, which accounts for 24 % of the total mean concentration. In contrast to sulfate, nitrate shows only a low percentage of 8.1 %. Further major ions are sodium (20%) and chloride (19 %), which are typical seasalt ions in coastal fog. High correlations between the measured ions suggest a causal link between concentration in the fog samples and the liquid water content (LWC) of the cloud. The higher the liquid water content the lower are the ionic concentrations. Enrichment factors with sodium as reference ion were calculated to identify potential emission sources contributing to the observed pollutant levels. We found that K+, Na+, Mg2+ and Cl- mainly result from seaspray. Sulfate, however, is enriched by a factor of 13. The measured trace elements are highly enriched by factors up to hundreds of thousands (Zn: 50, Ni: 1800, As: 2400, Cd: 3900, Fe: 100000, Cu: 96000, Pb: 250000). A cluster analysis supports the conclusion that sulfate and the trace elements originate from anthropogenic activities. The sulfate cannot primarily originate from

  20. Effects of acid precipitation on crops

    SciTech Connect

    Lee, J.J.

    1981-01-01

    The effects of acid rain on crop yield have been studied using field-grown and potted plants. Results have shown that the chemicals in acid rain can affect crop growth and yield at ambient concentrations. For many crops, the dose-response curve probably has at least one peak and crossover point from stimulatory to inhibitory response may depend on other environmental factors. Plant parts often are affected differently, suggesting that acid rain can change the allocation of energy within plants. Available experimental results are not transferable to agricultural situations. The characteristics of acid rain which have the greatest influence on crop yield have not been determined. Interactions between acid rain and other environmental factors have scarcely been studied. Before a believable assessment of the economic impact of acid rain on crops can be done, the mechanisms of response have to be studied and the predictive capability enhanced and validated.

  1. Pattern recognition applied to infrared images for early alerts in fog

    NASA Astrophysics Data System (ADS)

    Boucher, Vincent; Marchetti, Mario; Dumoulin, Jean; Cord, Aurélien

    2014-09-01

    Fog conditions are the cause of severe car accidents in western countries because of the poor induced visibility. Its forecast and intensity are still very difficult to predict by weather services. Infrared cameras allow to detect and to identify objects in fog while visibility is too low for eye detection. Over the past years, the implementation of cost effective infrared cameras on some vehicles has enabled such detection. On the other hand pattern recognition algorithms based on Canny filters and Hough transformation are a common tool applied to images. Based on these facts, a joint research program between IFSTTAR and Cerema has been developed to study the benefit of infrared images obtained in a fog tunnel during its natural dissipation. Pattern recognition algorithms have been applied, specifically on road signs which shape is usually associated to a specific meaning (circular for a speed limit, triangle for an alert, …). It has been shown that road signs were detected early enough in images, with respect to images in the visible spectrum, to trigger useful alerts for Advanced Driver Assistance Systems.

  2. In-field fast calibration of FOG-based MWD IMU for horizontal drilling

    NASA Astrophysics Data System (ADS)

    Li, Baoguo; Lu, Jiazhen; Xiao, Wenhua; Lin, Tie

    2015-03-01

    A fiber optic gyroscope (FOG)-based measuring-while-drilling (MWD) device for horizontal drilling is developed and an in-field fast calibration method of the MWD inertial measurement unit (IMU) is presented. The IMU consists of a FOG triad and a quartz accelerometer triad. An error model for the inertial sensors is established and 12 errors are confirmed as the main error sources for horizontal drilling after an analysis. A five-rotation-in-level-plane (5RILP) in-field fast calibration scheme for the main errors of the MWD IMU is illustrated. The scheme can be conveniently implemented on an almost level plane, such as a table plane, without any special external equipment. To solve the calibrated errors, a systematic approach based on specific force measurement observation is adopted. Observation equations of the IMU errors are derived according to the rotation sequence of the calibration scheme. Simulation results show that the proposed calibration method is effective even if there are 5° errors in level and 10° errors in heading. Calibration experiments using the developed FOG-based MWD equipment on a table plane confirm the validity of the proposed in-field calibration method. Inertial navigation tests show that the actual accuracy of the MWD IMU is greatly improved by 60.6% after in-field calibration.

  3. [PM2.5 pollution and aerosol optical properties in fog and haze days during autumn and winter in Beijing area].

    PubMed

    Zhao, Xiu-Juan; Pu, Wei-Wei; Meng, Wei; Ma, Zhi-Qiang; Dong, Fan; He, Di

    2013-02-01

    A study on the PM2.5 pollution and aerosol optical properties in haze-fog days was carried out from Sep. 1st to Dec. 7th, 2011 in Beijing area by using PM2.5 concentration, aerosol scattering coefficient (sigma sca) and absorption coefficient (sigma abs) measured under urban and rural environment. The effect of weather condition on the PM25 pollution and aerosol optical properties was discussed as well. The results showed that the PM2.5 concentration, sigma sca and sigma abs, were evidently higher in haze-fog days than those in non-haze-fog days. The average PM2.5 concentrations in haze-fog days with values of 97.6 microg m-3 and 64.4 microg.m-3 were as 3.3 and 4.8 times as those in non-haze-fog days at urban and rural stations, respectively. The higher PM2.5 concentration in urban area resulted in the more frequent fog and haze phenomena than that in rural area. The PM25 concentration, sigma sca, and sigma abs were significantly higher in urban area than that in rural area in mist days, while relatively close in mist-haze days. This difference suggested that the effect of regional transport of pollution was relatively evident in mist-haze days but weak in mist day. In fog days the sigma sca showed no evident difference between urban and rural area, and was the highest in all types of fog and haze weather. The scattering property of aerosol was the strongest in fog days. The different weather conditions resulted in various characteristics of spatial distribution of PM2.5 concentration, sigma sca and sigma abs, as well as the strength of PM2,5 pollution and aerosol extinction. The pollutants transported by the strong southwest wind above the boundary layer and subsided in the boundary layer companying with the local accumulation of pollutants due to the weak diffusion resulted in the most serious haze-fog episode with the strongest PM2.5 pollution and aerosol extinction.

  4. Numerical simulation of radiation fog in complex terrain

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Musson-Genon, L.; Carissimo, B.; Dupont, E.

    2009-09-01

    The interest for micro-scale modeling of the atmosphere is growing for environmental applications related, for example, to energy production, transport and urban development. The turbulence in the stable layers where pollutant dispersion is low and can lead to strong pollution events. This could be further complicated by the presence of clouds or fog and is specifically difficult in urban or industrial area due to the presence of buildings. In this context, radiation fog formation and dissipation over complex terrain were therefore investigated with a state-of-the-art model. This study is divided into two phases. The first phase is a pilot stage, which consist of employing a database from the ParisFog campaign which took place in the south of Paris during winter 2006-07 to assess the ability of the cloud model to reproduce the detailed structure of radiation fog. The second phase use the validated model for the study of influence of complex terrain on fog evolution. Special attention is given to the detailed and complete simulations and validation technique used is to compare the simulated results using the 3D cloud model of computational fluid dynamical software Code_Saturne with one of the best collected in situ data during the ParisFog campaign. Several dynamical, microphysical parameterizations and simulation conditions have been described. The resulting 3D cloud model runs at a horizontal resolution of 30 m and a vertical resolution comparable to the 1D model. First results look very promising and are able to reproduce the spatial distribution of fog. The analysis of the behavior of the different parameterized physical processes suggests that the subtle balance between the various processes is achieved.

  5. The Identification and Structure of an N-Terminal PR Domain Show that FOG1 Is a Member of the PRDM Family of Proteins

    PubMed Central

    Clifton, Molly K.; Westman, Belinda J.; Thong, Sock Yue; O’Connell, Mitchell R.; Webster, Michael W.; Shepherd, Nicholas E.; Quinlan, Kate G.; Crossley, Merlin; Blobel, Gerd A.; Mackay, Joel P.

    2014-01-01

    FOG1 is a transcriptional regulator that acts in concert with the hematopoietic master regulator GATA1 to coordinate the differentiation of platelets and erythrocytes. Despite considerable effort, however, the mechanisms through which FOG1 regulates gene expression are only partially understood. Here we report the discovery of a previously unrecognized domain in FOG1: a PR (PRD-BF1 and RIZ) domain that is distantly related in sequence to the SET domains that are found in many histone methyltransferases. We have used NMR spectroscopy to determine the solution structure of this domain, revealing that the domain shares close structural similarity with SET domains. Titration with S-adenosyl-L-homocysteine, the cofactor product synonymous with SET domain methyltransferase activity, indicated that the FOG PR domain is not, however, likely to function as a methyltransferase in the same fashion. We also sought to define the function of this domain using both pulldown experiments and gel shift assays. However, neither pulldowns from mammalian nuclear extracts nor yeast two-hybrid assays reproducibly revealed binding partners, and we were unable to detect nucleic-acid-binding activity in this domain using our high-diversity Pentaprobe oligonucleotides. Overall, our data demonstrate that FOG1 is a member of the PRDM (PR domain containing proteins, with zinc fingers) family of transcriptional regulators. The function of many PR domains, however, remains somewhat enigmatic for the time being. PMID:25162672

  6. Characteristics of water-soluble ions before, during and after fog events

    NASA Astrophysics Data System (ADS)

    Li, P.; Du, H.; Yang, C.; Yao, J.; Du, J.; Chen, J.

    2010-07-01

    Two atmospheric processes of rain-fog-haze and haze-fog-rain were observed on Feb.8th and Mar. 14th, 2010 in urban Shanghai. On-line characterization of water-soluble ions of aerosol was performed before, during and after two fog episodes by an instrument of Monitoring AeRosoles and GAses (MARGA). Fog water samples were also collected to study the chemical ion characteristics for identifying the property of fogs. After rain, total water-soluble ion concentration in PM2.5 increased by 71.9%. Afterwards, a fog formation was observed as a frontal fog. Six fog water samples were collected to measure concentration of water-soluble ions, whose total concentrations decreased from beginning to end of fog. At the end of fog, the total water-soluble ion concentration of aerosol was continually increased. Meanwhile with a sharp decline of RH down to 70% in two hours, and a haze episode was observed. The reverse process, haze-fog-rain process, was also investigated. After the haze episode, total water-soluble ions concentration of aerosol rarely increased, but fog appeared with sharp increase of RH. Concentration of water-soluble ions in the fog water sample was higher than mean concentration of samples in 2009. When the fog started to disperse, the ion concentration hardly changed. As water vapor continued to increase, rain was observed. The inorganic compositions of aerosol in both fog events were dominated by sulfate and ammonium. The in situ investigation clearly illustrated that fog water mainly influenced by continental sources was dirtier and contained more sediment comparing with fog water influenced by marine sources.

  7. Blue-green pulsed propagation through fog.

    PubMed

    Mooradian, G C; Geller, M; Stotts, L B; Stephens, D H; Krautwald, R A

    1979-02-15

    Measurements and analysis of a blue-green pulsed propagation through fog have identified three distinct regions for energy transport. Region I small number of attenuation lengths tau in the path (0 32): the direct beam and the forwardscattered beam have decayed to the point where the diffusion type multiple-scattered radiation is the dominant energy received. This component does not decay exponentially but results in large spatial, angular, and temporal spreading. This paper presents quantitative data on Region II. PMID:20208740

  8. Ocular Findings in Volcanic Fog Induced Conjunctivitis

    PubMed Central

    Lagunzad, John Kenneth D

    2011-01-01

    Objective To describe the ocular signs and symptoms of patients complaining of eye irritation due to volcanic fog (vog). Methods The study utilized a non-comparative, retrospective chart review of 30 patients who had a chief complaint of eye irritation, which the subjects attributed to vog. Ocular signs and symptoms are described and related to the ambient concentration of sulfur dioxide (SO2), particulate matter sized 2.5 microns (PM2.5), and vog visibility in O‘ahu during the period of the study. Results Ocular signs noted were conjunctival injection (100%), clear mucous discharge (100%), papillary reaction (100%), punctal edema (80%), eyelid swelling (73.3%) and chemosis (63.3%). Ocular symptoms were itchiness (100%), foreign body sensation (100%), tearing (96.6%) and burning sensation (90%). All patients had concurrent respiratory symptoms. During the period of study, the highest 24-hour average concentration of particulate matter sized 2.5 microns (PM2.5) was 49.04 µg/m3 and vog was visually present. Conclusions Patients complaining of eye irritation due to vog have observable ocular signs and symptoms. PMID:22187513

  9. Fog as an ecosystem service: Quantifying fog-mediated reductions in maximum temperature across coastal to inland transects in northern California

    NASA Astrophysics Data System (ADS)

    Torregrosa, A.; Flint, L. E.; Flint, A. L.; Combs, C.; Peters, J.

    2013-12-01

    Several studies have documented the human benefits of temperature cooling derived from coastal fog such as the reduction in the number of hospital visits/emergency response requests from heat stress-vulnerable population sectors or decreased energy consumption during periods when summer maximum temperatures are lower than normal. In this study we quantify the hourly, daily, monthly and seasonal thermal effect of fog and low clouds (FLC) hours on maximum summer temperatures across a northern California landscape. The FLC data summaries are calculated from the CIRA (Cooperative Institute for Research in the Atmosphere) 10 year archive that were derived from hourly night and day images using channels 1 (Visible), 2 (3.6 μm) and 4 (10.7 μm) NOAA GOES (Geostationary Operational Environmental Satellite). The FLC summaries were analyzed with two sets of site based data, meteorological (met) station-based measurements and downscaled interpolated PRISM data for selected point locations spanning a range of coastal to inland geographic conditions and met station locations. In addition to finding a 0.4 degree C per hour of FLC effect, our results suggest variability related to site specific thermal response. For example, sites closest to the coast have less thermal variability between low cloud and sunny days than sites further from the coast suggesting a much stronger influence of ocean temperature than of FLC thermal dynamics. The thermal relief provided by summertime FLC is equivalent in magnitude to the temperature increase projected by the driest and hottest of regional downscaled climate models using the A2 ('worst') IPCC scenario. Extrapolating these thermal calculations can facilitate future quantifications of the ecosystem service provided by summertime low clouds and fog.

  10. What Is Acid Rain?

    ERIC Educational Resources Information Center

    Likens, Gene E.

    2004-01-01

    Acid rain is the collective term for any type of acidified precipitation: rain, snow, sleet, and hail, as well as the presence of acidifying gases, particles, cloud water, and fog in the atmosphere. The increased acidity, primarily from sulfuric and nitric acids, is generated as a by-product of the combustion of fossil fuels such as coal and oil.…

  11. Oxidation enhancement of submicron organic aerosols by fog processing

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Ge, X.; Collier, S.; Setyan, A.; Xu, J.; Sun, Y.

    2011-12-01

    During 2010 wintertime, a measurement study was carried out at Fresno, California, using an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) combined with a Scanning Mobility Particle Sizer (SMPS). Four fog events occurred during the first week of the campaign. While ambient aerosol was sampled into the HR-ToF-AMS, fog water samples were collected, and were later aerosolized and analyzed via HR-TOF-AMS in the laboratory. We performed Positive Matrix Factorization (PMF) on the AMS ambient organic mass spectra, and identified four OA factors: hydrocarbon-like OA (HOA) likely from vehicle emissions, cooking influenced OA (COA), biomass burning OA (BBOA) representing residential wood combustion, and an oxygenated OA (OOA) that has an average O/C ratio of 0.42. The time series of the OOA factor correlates best with that of sulfate (R2 =0.54 ) during fog events, suggesting that aqueous phase processing may have strongly affected OOA production during wintertime in Fresno. We further investigate the OOA compositions and elemental ratios before, during, and after the fog events, as well as those of dissolved organic matter (DOM) in fog waters to study the influence of aqueous phase processing on OA compositions. Results of fog sample analysis shows an enhancement of oxidation of DOM in 11 separate fog samples. Further factor analysis of the fog DOM data will elucidate the possible mechanisms by which fog processing enhances oxidation of aerosol. In addition, in order to investigate the influence of aqueous processing on OA, we used the Extended Aerosol Inorganic Model (E-AIM) (http://www.aim.env.uea.ac.uk/aim/aim.php) to estimate aerosol phase water contents based on the AMS measured aerosol composition. The predicted water content has a good correlation with sulfate and OOA . We will further explore the correlations between particle phase water with organic aerosol characteristics to discuss the influence of aqueous phase processing on

  12. The influences of macro- and microphysical characteristics of sea-fog on fog-water chemical composition

    NASA Astrophysics Data System (ADS)

    Yue, Yanyu; Niu, Shengjie; Zhao, Lijuan; Zhang, Yu; Xu, Feng

    2014-05-01

    During a sea-fog field observation campaign on Donghai Island in the spring of 2011, fog-water, visibility, meteorological elements, and fog droplet spectra were measured. The main cations and anions in 191 fog-water samples were Na+, NH{4/+}, H+, NO{3/-}, Cl- and SO{4/2-}, and the average concentrations of cations and anions were 2630 and 2970 μeq L-1, respectively. The concentrations of Na+ and Cl- originated from the ocean were high. The enhancement of anthropogenic pollution might have contributed to the high concentration of NH{4/+}, H+, and NO{3/-}. The average values of pH and electrical conductivity (EC) were 3.34 and 505 μS cm-1, respectively, with a negative correlation between them. Cold fronts associated with cyclonic circulations promoted the decline of ion loadings. Air masses from coastal areas had the highest ion loadings, contrary to those from the sea. The ranges of wind speed, wind direction and temperature corresponding to the maximum total ion concentration (TIC) were 3.5-4 m s-1, 79°-90° and 21°C-22°C, respectively. In view of the low correlation coefficients, a new parameter Lr was proposed as a predictive parameter for TIC and the correlation coefficient increased to 0.74. Based on aerosol concentrations during the sea-fog cases in 2010, we confirmed that fog-water chemical composition also depended on the species and sizes of aerosol particles. When a dust storm passed through Donghai Island, the number concentration of large aerosol particles (with diameter > 1 μm) increased. This caused the ratio of Ca2+/Na+ in fog-water to increase significantly.

  13. Genotoxic effect of substituted phenoxyacetic acids.

    PubMed

    Venkov, P; Topashka-Ancheva, M; Georgieva, M; Alexieva, V; Karanov, E

    2000-11-01

    The potential toxic and mutagenic action of 2,4-dichlorophenoxyacetic acid has been studied in different test systems, and the obtained results range from increased chromosomal damage to no effect at all. We reexamined the effect of this herbicide by simultaneous using three tests based on yeast, transformed hematopoietic, and mouse bone marrow cells. The results obtained demonstrated that 2,4-dichlorophenoxyacetic acid has cytotoxic and mutagenic effects. The positive response of yeast and transformed hematopoietic cells was verified in kinetics and dose-response experiments. The analysis of metaphase chromosomes indicated a statistically proved induction of breaks, deletions, and exchanges after the intraperitoneal administration of 2,4-dichlorophenoxyacetic acid in mice. The study of phenoxyacetic acid and its differently chlorinated derivatives showed that cytotoxicity and mutagenicity are induced by chlorine atoms at position 2 and/or 4 in the benzene ring. The mutagenic effect was abolished by introduction of a third chlorine atom at position 5. Thus 2,4,5-trichlorophenoxyacetic acid was found to have very weak, if any mutagenic effect; however, the herbicide preserved its toxic effect.

  14. Effects of hydroxymethanesulfonate on airway function in subjects with asthma. Final report

    SciTech Connect

    Sheppard, D.; Balmes, J.R.; Aris, R.M.; Christian, D.

    1989-06-30

    The organic ion hydroxymethanesulfonate (HMSA) has been measured in micro-molecular concentrations in acidic fogs in southern California. HMSA is a stable adduct in fogs with a pH range of 3-5, but it is likely to dissociate at pH 6.6, the pH of the human airways fluid lining. It was hypothesized that HMSA may have a specific bronchoconstrictor effect because HMSA may dissociate in the airway lumen generating SO{sub 2} and CH{sub 2}O, both of which have bronchoconstrictor potential. In order to determine whether HMSA has such an effect, a total of 19 subjects with mild to moderate asthma were studied in an exposure chamber in which freely breathing and exercising subjects inhaled simulated fogs containing HMSA at a concentration (1000 micro M) higher than the ambient levels for 1 hour. The results indicated no significant bronchoconstrictor effect for acute exposures of HMSA.

  15. Relation Between Fog & Summer Stream Flow on the North Coast of California in Redwood National Park

    NASA Astrophysics Data System (ADS)

    Lavery, K.

    2012-12-01

    There are three common definitions of fog; visibility less than 800 meters (Dawson 1998), ceiling height less than 400 meters (Liepper 1995, Johnstone & Dawson 2010) or low level stratus that touches the ground. Regardless of the definition used the ecological importance of fog is evidenced by the commonly used term occult precipitation i.e. water that is not accounted for. Fog is most common on the coast of Northern California during summer, the time of least precipitation. The diurnal flux in stream flows is also most evident in the summer. Diurnal flux and seasonal trends in stream flow are thought to be controlled by precipitation and evapotranspiration. Fog impacts both precipitation and evapotranspiration. While changes in fog regimes are expected to occur as a result of climate change, the ability to measure fog and anticipate the implications are in nascent stages. Although, methods for detecting fog using satellite imagery have been developed they have not been perfected and they generally only give height info for the cloud deck (top of clouds). Although deck height is important for aviation and enables some inference of what is occurring on the ground the thickness and base height are important variables for developing a greater understanding of the impacts of fog. Fog harps will be used to detect fog on the ground. Fog harp data will be compared with the results of satellite imagery analysis for presence or absence of fog. After detrending, stream flow data will be divided into categories of fog and no fog. The two categories will be tested for a statistically significant difference. The results have the potential to help solve a piece of the climate change puzzle. The data will help with the anticipation of change in stream flows in areas with high levels of summer fog and Mediterranean climates as well as refine techniques for analyzing satellite imagery for presence or absence of fog.

  16. Anti-Diabetic Effects of Madecassic Acid and Rotundic Acid.

    PubMed

    Hsu, Yuan-Man; Hung, Yi-chih; Hu, Lihong; Lee, Yi-ju; Yin, Mei-chin

    2015-12-01

    Anti-diabetic effects of madecassic acid (MEA) and rotundic acid (RA) were examined. MEA or RA at 0.05% or 0.1% was supplied to diabetic mice for six weeks. The intake of MEA, not RA, dose-dependently lowered plasma glucose level and increased plasma insulin level. MEA, not RA, intake dose-dependently reduced plasminogen activator inhibitor-1 activity and fibrinogen level; as well as restored antithrombin-III and protein C activities in plasma of diabetic mice. MEA or RA intake decreased triglyceride and cholesterol levels in plasma and liver. Histological data agreed that MEA or RA intake lowered hepatic lipid droplets, determined by ORO stain. MEA intake dose-dependently declined reactive oxygen species (ROS) and oxidized glutathione levels, increased glutathione content and maintained the activity of glutathione reductase and catalase in the heart and kidneys of diabetic mice. MEA intake dose-dependently reduced interleukin (IL)-1β, IL-6, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels in the heart and kidneys of diabetic mice. RA intake at 0.1% declined cardiac and renal levels of these inflammatory factors. These data indicated that MEA improved glycemic control and hemostatic imbalance, lowered lipid accumulation, and attenuated oxidative and inflammatory stress in diabetic mice. Thus, madecassic acid could be considered as an anti-diabetic agent. PMID:26633490

  17. Anti-Diabetic Effects of Madecassic Acid and Rotundic Acid

    PubMed Central

    Hsu, Yuan-Man; Hung, Yi-chih; Hu, Lihong; Lee, Yi-ju; Yin, Mei-chin

    2015-01-01

    Anti-diabetic effects of madecassic acid (MEA) and rotundic acid (RA) were examined. MEA or RA at 0.05% or 0.1% was supplied to diabetic mice for six weeks. The intake of MEA, not RA, dose-dependently lowered plasma glucose level and increased plasma insulin level. MEA, not RA, intake dose-dependently reduced plasminogen activator inhibitor-1 activity and fibrinogen level; as well as restored antithrombin-III and protein C activities in plasma of diabetic mice. MEA or RA intake decreased triglyceride and cholesterol levels in plasma and liver. Histological data agreed that MEA or RA intake lowered hepatic lipid droplets, determined by ORO stain. MEA intake dose-dependently declined reactive oxygen species (ROS) and oxidized glutathione levels, increased glutathione content and maintained the activity of glutathione reductase and catalase in the heart and kidneys of diabetic mice. MEA intake dose-dependently reduced interleukin (IL)-1β, IL-6, tumor necrosis factor-α and monocyte chemoattractant protein-1 levels in the heart and kidneys of diabetic mice. RA intake at 0.1% declined cardiac and renal levels of these inflammatory factors. These data indicated that MEA improved glycemic control and hemostatic imbalance, lowered lipid accumulation, and attenuated oxidative and inflammatory stress in diabetic mice. Thus, madecassic acid could be considered as an anti-diabetic agent. PMID:26633490

  18. Assessing Middle School and College Students' Conceptions About Wind, Fog, and Tornadoes

    NASA Astrophysics Data System (ADS)

    Polito, E.; Monteverdi, J. P.; Garcia, O.; Tanner, K. D.

    2008-12-01

    protocol utilized in Phase III. A subset of the population was interviewed, allowing us to probe deeper into students' conceptions about weather. This three-phase approach allowed us to identify and explore misconceptions concerning wind, fog, and tornadoes. Preliminary results from phase I and II probing student conceptions of wind show that over 54% of 6th grade students do not see any connection between the sun and wind, offering instead that the moon, clouds, and the ocean are key contributors to wind development. 13% of students observe that because there is wind at night, and conclude from this that the sun could not play a role in creating wind. By identifying students' misconceptions about wind, fog, and tornadoes, scientists and educators can create more effective learning experiences that address student misconceptions, promote conceptual change, and move students toward a more scientific viewpoint.

  19. Bioinspired plate-based fog collectors.

    PubMed

    Heng, Xin; Luo, Cheng

    2014-09-24

    In a recent work, we explored the feeding mechanism of a shorebird to transport liquid drops by repeatedly opening and closing its beak. In this work, we apply the corresponding results to develop a new artificial fog collector. The collector includes two nonparallel plates. It has three advantages in comparison with existing artificial collectors: (i) easy fabrication, (ii) simple design to scale up, and (iii) active transport of condensed water drops. Two collectors have been built. A small one with dimensions of 4.2 × 2.1 × 0.05 cm(3) (length × width × thickness) was first built and tested to examine (i) the time evolution of condensed drop sizes and (ii) the collection processes and efficiencies on the glass, SiO2, and SU-8 plates. Under similar experimental conditions, the amount of water collected per unit area on the small collector is about 9.0, 4.7, and 3.7 times, respectively, as much as the ones reported for beetles, grasses, and metal wires, and the total amount of water collected is around 33, 18, and 15 times. On the basis of the understanding gained from the tests on the small collector, a large collector with dimensions of 26 × 10 × 0.2 cm(3) was further built and tested, which was capable of collecting 15.8 mL of water during a period of 36 min. The amount of water collected, when it is scaled from 36 to 120 min, is about 878, 479, or 405 times more than what was collected by individual beetles, grasses, or metal wires.

  20. Bioinspired plate-based fog collectors.

    PubMed

    Heng, Xin; Luo, Cheng

    2014-09-24

    In a recent work, we explored the feeding mechanism of a shorebird to transport liquid drops by repeatedly opening and closing its beak. In this work, we apply the corresponding results to develop a new artificial fog collector. The collector includes two nonparallel plates. It has three advantages in comparison with existing artificial collectors: (i) easy fabrication, (ii) simple design to scale up, and (iii) active transport of condensed water drops. Two collectors have been built. A small one with dimensions of 4.2 × 2.1 × 0.05 cm(3) (length × width × thickness) was first built and tested to examine (i) the time evolution of condensed drop sizes and (ii) the collection processes and efficiencies on the glass, SiO2, and SU-8 plates. Under similar experimental conditions, the amount of water collected per unit area on the small collector is about 9.0, 4.7, and 3.7 times, respectively, as much as the ones reported for beetles, grasses, and metal wires, and the total amount of water collected is around 33, 18, and 15 times. On the basis of the understanding gained from the tests on the small collector, a large collector with dimensions of 26 × 10 × 0.2 cm(3) was further built and tested, which was capable of collecting 15.8 mL of water during a period of 36 min. The amount of water collected, when it is scaled from 36 to 120 min, is about 878, 479, or 405 times more than what was collected by individual beetles, grasses, or metal wires. PMID:25192549

  1. Fog collecting biomimetic surfaces: Influence of microstructure and wettability.

    PubMed

    Azad, M A K; Ellerbrok, D; Barthlott, W; Koch, K

    2015-01-19

    We analyzed the fog collection efficiency of three different sets of samples: replica (with and without microstructures), copper wire (smooth and microgrooved) and polyolefin mesh (hydrophilic, superhydrophilic and hydrophobic). The collection efficiency of the samples was compared in each set separately to investigate the influence of microstructures and/or the wettability of the surfaces on fog collection. Based on the controlled experimental conditions chosen here large differences in the efficiency were found. We found that microstructured plant replica samples collected 2-3 times higher amounts of water than that of unstructured (smooth) samples. Copper wire samples showed similar results. Moreover, microgrooved wires had a faster dripping of water droplets than that of smooth wires. The superhydrophilic mesh tested here was proved more efficient than any other mesh samples with different wettability. The amount of collected fog by superhydrophilic mesh was about 5 times higher than that of hydrophilic (untreated) mesh and was about 2 times higher than that of hydrophobic mesh.

  2. Salt Fog Testing Iron-Based Amorphous Alloys

    SciTech Connect

    Rebak, Raul B.; Aprigliano, Louis F.; Day, S. Daniel; Farmer, Joseph C.

    2007-07-01

    Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

  3. A Molecular Explanation of How the Fog Is Produced When Dry Ice Is Placed in Water

    ERIC Educational Resources Information Center

    Kuntzleman, Thomas S.; Ford, Nathan; No, Jin-Hwan; Ott, Mark E.

    2015-01-01

    Everyone enjoys seeing the cloudy white fog generated when solid carbon dioxide (dry ice) is placed in water. Have you ever wondered what physical and chemical processes occur to produce this fog? When asked this question, many chemical educators suggest that the fog is produced when atmospheric water vapor condenses on cold carbon dioxide gas…

  4. The structure and formation mechanism of a sea fog event over the Yellow Sea

    NASA Astrophysics Data System (ADS)

    Guo, Jingtian; Li, Pengyuan; Fu, Gang; Zhang, Wei; Gao, Shanhong; Zhang, Suping

    2015-02-01

    In this paper, a heavy sea fog event occurring over the Yellow Sea on 11 April 2004 was investigated based upon observational and modeling analyses. From the observational analyses, this sea fog event is a typical advection cooling case. Sea surface temperature (SST) and specific humidity (SH) show strong gradients from south to north, in which warm water is located in the south and consequently, moisture is larger in the south than in the north due to evaporation processes. After fog formation, evaporation process provides more moisture into the air and further contributes to fog evolution. The sea fog event was reproduced by the Regional Atmospheric Modeling System (RAMS) reasonably. The roles of important physical processes such as radiation, turbulence as well as atmospheric stratification in sea fog's structure and its formation mechanisms were analyzed using the model results. The roles of long wave radiation cooling, turbulence as well as atmospheric stratification were analyzed based on the modeling results. It is found that the long wave radiative cooling at the fog top plays an important role in cooling down the fog layer through turbulence mixing. The fog top cooling can overpower warming from the surface. Sea fog develops upward with the aid of turbulence. The buoyancy term, i.e., the unstable layer, contributes to the generation of TKE in the fog region. However, the temperature inversion layer prevents fog from growing upward.

  5. Heat transfer from a high temperature condensable mixture. II. Sedimentation of fog condensate

    SciTech Connect

    Condiff, D.W.; Cho, D.H.; Chan, S.H.

    1985-01-01

    A kinematic wave analysis of fog sedimentation is employed to relate growth of a fog condensate deposit layer to radiation generated fog formation rates. The increase of surface radiation absorptivity with deposit layer thickness promotes a feedback mechanism for higher growth rates, which is evaluated in detail.

  6. Fogs and Clouds are a Potential Indicator of a Local Water Source in Valles Marineris

    NASA Astrophysics Data System (ADS)

    Leung, Cecilia W. S.; Rafkin, Scot C. R.; Stillman, David E.; McEwen, Alfred S.

    2016-04-01

    atmospheric origin of volatiles. If nocturnal clouds and fogs are present in Valles Marineris and not on the surrounding terrain, the modeled atmospheric thermal field points to an active source of water in the canyon. This source may be related to the water source for RSL and bolsters the hypothesis for a subsurface water reservoir. An atmospheric origin of water for RSL via deliquescence on salt requires an effective mechanism to trap water over small areas to support the estimated volumes of water in RSL. No such mechanism has been identified. However, there is evidence that the atmosphere still exerts control on the formation and activity of RSL through thermal effects. References: [1] McEwen, A. et al., (2011) Science, 333, 740-743. [2] McEwen, A. et al., (2014) Nature GeoSci, 7, 53-58. [3] Stillman, D. et al. (2016) Icarus, 265, 125-138. [4] McEwen, A. et al., (2015) EPSC, 786. [5] Wang., A. et al., 46th LPSC, #2483. [6] Möhlmann, D.T. et al. (2009) Planetary and Space Science, 57(14), 1987-1992. [7] Smith, M. (2008) AREPS 36, 191-219.

  7. Effects of acid deposition on agricultural production

    SciTech Connect

    Moskowitz, P.D.; Medeiros, W.H.; Oden, N.L.; Thode, H.C. Jr.; Coveney, E.A.; Jacobson, J.S.; Rosenthal, R.E.; Evans, L.S.; Lewin, K.F.; Allen, F.L.

    1985-09-01

    A preliminary assessment, both qualitative and quantitative, was carried out on the effects of acid deposition on agriculture. An inventory was made of US crops exposed to different acid deposition levels in 1982. Most crops (valued at more than $50 billion) were exposed to annual average acid deposition levels greater than pH 4.6, but crops worth more than $220 billion were exposed to even lower pH levels. Published results of experiments on crop response to acid deposition have not identified any single crop as being consistently sensitive, and suggest that present levels of acidic precipitation in the US are not significantly affecting growth and yield of crops. Because relatively few experiments appropriate to a quantitative acid deposition assessment have been conducted, the quantitative section is necessarily based on a restricted data set. Corn, potatoes, and soybeans have been studied in experimental environments which simulate agronomic conditions and which have adequate statistical power for yield estimates; only some varieties of soybeans have demonstrated statistically significant sensitivity to acid deposition.

  8. Effect of folic acid on zinc absorption

    SciTech Connect

    Wada, L.; Keating, S.; King, J.C.; Stokstad, E.L.R.

    1986-03-05

    The effect of folic acid on zinc uptake was studied in the human and in the rat. The serum zinc response to a 25 mg oral dose or zinc was measured with and without a 10 mg dose of folic acid. Serum zinc levels were measured prior to the oral dose of zinc and at hourly intervals up to 4 hours after the dose. When zinc was given along, the increases in serum zinc from baseline at hours 1, 2, 3 and 4 were 92, 118, 92 and 66 ..mu..g/dl, respectively. When both zinc and folic acid were given, the increases in serum zinc at hours 1, 2, 3 and 4 were 100, 140, 110 and 75 ..mu..g/dl, respectively. When the increases in serum zinc were plotted against time, there was no significant difference between the areas under the two curves. The everted jejunal sac from the rat was used to study the effect of folate on zinc transport using 100 ..mu..M zinc in the mucosal buffer. The addition of folic acid at levels up to 10/sup -3/M had no significant effect on zinc transport to the serosal side solution or on uptake by the intestinal mucosa. This in vivo study with humans and in vitro study with rat intestine does not support a direct adverse effect of folic acid on zinc absorption.

  9. Why do drivers maintain short headways in fog? A driving-simulator study evaluating feeling of risk and lateral control during automated and manual car following.

    PubMed

    Saffarian, M; Happee, R; Winter, J C F de

    2012-01-01

    Drivers in fog tend to maintain short headways, but the reasons behind this phenomenon are not well understood. This study evaluated the effect of headway on lateral control and feeling of risk in both foggy and clear conditions. Twenty-seven participants completed four sessions in a driving simulator: clear automated (CA), clear manual (CM), fog automated (FA) and fog manual (FM). In CM and FM, the drivers used the steering wheel, throttle and brake pedals. In CA and FA, a controller regulated the distance to the lead car, and the driver only had to steer. Drivers indicated how much risk they felt on a touchscreen. Consistent with our hypothesis, feeling of risk and steering activity were elevated when the lead car was not visible. These results might explain why drivers adopt short headways in fog. Practitioner Summary: Fog poses a serious road safety hazard. Our driving-simulator study provides the first experimental evidence to explain the role of risk-feeling and lateral control in headway reduction. These results are valuable for devising effective driver assistance and support systems.

  10. Estimation of fog deposition on epiphytic bryophytes in a subtropical montane forest ecosystem in northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Chieh; Lai, I.-Ling; Wu, Jiunn-Tzong

    The fog meteorology, fog chemistry and fog deposition on epiphytic bryophytes were investigated from July 2000 to June 2001 in the Yuanyang Lake forest ecosystem. The elevation of the site ranges from 1650 to 2420 m, at which the high frequency of fog occurrence throughout the year has been thought to be of benefit to the establishment of the primary Taiwan yellow cypress forest [ Chamaecyparis obtusa var. formosana (Hayata) Rehder] and to the extensive growth of the epiphytic bryophytes. A weather station including a visibility sensor and an active fog collector was installed for fog meteorological and chemical study. The fog deposition rate on epiphytic bryophytes was estimated by measuring the increase rate in plant weight when exposed to fog. Average fog duration of 4.7 and 11.0 h per day was measured in summer months (June to August) and the rest of the year, respectively. November 2000 was the foggiest month in which the average fog duration reached 14.9 h per day. The ionic composition of fog water revealed that the area was less polluted than expected from literature data. The in situ exposure experiments done with the dominant epiphytic bryophytes showed an average fog deposition rate of 0.63 g H 2O g -1 d. w. h -1, which approximated 0.17 mm h -1 at the stand scale. The nutrient fluxes estimated for February 2001 showed that for all ions, more than 50% of the ecosystem input was through fog deposition. These results demonstrate the importance of epiphytic bryophytes and fog deposition in nutrient cycling of this subtropical montane forest ecosystem. The incorporation of fog study in the long-term ecosystem research projects is necessary in this area.

  11. The Climatology, Frequency, and Distribution of Cold Season Fog Events in Northern Utah

    NASA Astrophysics Data System (ADS)

    Hodges, Derek; Pu, Zhaoxia

    2015-10-01

    The distribution and frequency of fog events during the cold season in northern Utah is studied using surface Mesowest data from 2004 to 2014. Fog is identified using the reported weather conditions, relative humidity, and visibility. The length and time of each fog occurrence is calculated. Statistics are performed on daily, monthly, and seasonal timescales. To ensure representativeness of the data and to account for the relatively small sample size, "near-fog" conditions are included in some statistics. Results show that there is significant variability among the valleys in northern Utah in terms of both quantity and timing of fog events. Fog occurs more frequently in locations close to lakes such as the Great Salt Lake or Utah Lake than in locations farther away. It is also noted that small, enclosed valleys have higher amounts of fog than broader, open valleys. Throughout the region, there is a distinct peak in fog in late January for most stations. A strong peak in fog occurrences near dawn is also found for all cold season months. In addition, the influence of local, mesoscale conditions on the fog distribution is evident in many stations. It is found that the existence of fog at one location is a very poor predictor of fog at nearby locations on a daily timescale, which implies serious forecasting difficulties over complex terrain. However, it is also found that on an annual timescale the amount of fog at one location can be used to estimate the amount of fog at another location. The controlling factors that contribute to the variability of fog events over northern Utah (a mountainous region) are discussed.

  12. The Climatology, Frequency, and Distribution of Cold Season Fog Events in Northern Utah

    NASA Astrophysics Data System (ADS)

    Hodges, Derek; Pu, Zhaoxia

    2016-09-01

    The distribution and frequency of fog events during the cold season in northern Utah is studied using surface Mesowest data from 2004 to 2014. Fog is identified using the reported weather conditions, relative humidity, and visibility. The length and time of each fog occurrence is calculated. Statistics are performed on daily, monthly, and seasonal timescales. To ensure representativeness of the data and to account for the relatively small sample size, "near-fog" conditions are included in some statistics. Results show that there is significant variability among the valleys in northern Utah in terms of both quantity and timing of fog events. Fog occurs more frequently in locations close to lakes such as the Great Salt Lake or Utah Lake than in locations farther away. It is also noted that small, enclosed valleys have higher amounts of fog than broader, open valleys. Throughout the region, there is a distinct peak in fog in late January for most stations. A strong peak in fog occurrences near dawn is also found for all cold season months. In addition, the influence of local, mesoscale conditions on the fog distribution is evident in many stations. It is found that the existence of fog at one location is a very poor predictor of fog at nearby locations on a daily timescale, which implies serious forecasting difficulties over complex terrain. However, it is also found that on an annual timescale the amount of fog at one location can be used to estimate the amount of fog at another location. The controlling factors that contribute to the variability of fog events over northern Utah (a mountainous region) are discussed.

  13. Analysis of atmospheric turbulence in the upper layers of sea fog

    NASA Astrophysics Data System (ADS)

    Li, Yongping; Zheng, Yunxia

    2015-05-01

    Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However, studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus, the turbulence characteristics of upper fog layers are poorly known. In this paper, we present 4-layers of data, measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy, momentum flux, and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset, high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold, it was crucial to enhancing the cooling rate, and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode, the vertical distribution of sensible heat flux reversed, contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog, than during the fog episode. Turbulence energy was greatest in upper levels, around 430 m and 450 m above mean sea level (AMSL), than in lower levels of the fog (390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer, affecting the underlying fog by decreasing or increasing average wind speed, as well as promoting or demoting air temperature stratification.

  14. Project Fog Drops 5. Task 1: A numerical model of advection fog. Task 2: Recommendations for simplified individual zero-gravity cloud physics experiments

    NASA Technical Reports Server (NTRS)

    Rogers, C. W.; Eadie, W. J.; Katz, U.; Kocmond, W. C.

    1975-01-01

    A two-dimensional numerical model was used to investigate the formation of marine advection fog. The model predicts the evolution of potential temperature, horizontal wind, water vapor content, and liquid water content in a vertical cross section of the atmosphere as determined by vertical turbulent transfer and horizontal advection, as well as radiative cooling and drop sedimentation. The model is designed to simulate the formation, development, or dissipation of advection fog in response to transfer of heat and moisture between the atmosphere and the surface as driven by advection over horizontal discontinuities in the surface temperature. Results from numerical simulations of advection fog formation are discussed with reference to observations of marine fog. A survey of candidate fog or cloud microphysics experiments which might be performed in the low gravity environment of a shuttle-type spacecraft in presented. Recommendations are given for relatively simple experiments which are relevent to fog modification problems.

  15. Effects of Docosahexaenoic Acid on Neurotransmission

    PubMed Central

    Tanaka, Kazuhiro; Farooqui, Akhlaq A.; Siddiqi, Nikhat J.; Alhomida, Abdullah S.; Ong, Wei-Yi

    2012-01-01

    Docosahexaenoic acid (DHA) is the major polyunsaturated fatty acid (PUFA) in the brain and a structural component of neuronal membranes. Changes in DHA content of neuronal membranes lead to functional changes in the activity of receptors and other proteins which might be associated with synaptic function. Accumulating evidence suggests the beneficial effects of dietary DHA supplementation on neurotransmission. This article reviews the beneficial effects of DHA on the brain; uptake, incorporation and release of DHA at synapses, effects of DHA on synapses, effects of DHA on neurotransmitters, DHA metabolites, and changes in DHA with age. Further studies to better understand the metabolome of DHA could result in more effective use of this molecule for treatment of neurodegenerative or neuropsychiatric diseases. PMID:24116288

  16. The Fiberoptle Guided Missile (FOG-M)

    NASA Astrophysics Data System (ADS)

    Jacobs, Paul L.

    1989-02-01

    The Fiberoptic Guided Missile (FOG-M) was developed in the U.S. Army's Research, Development, and Engineering Center (RDEC) as a demonstration system for killing armor in an infantry application. The RDEC design uses a television sensor in the nose of the missile for in-flight target acquisition, bringing the video signal down a fiberoptic link that pays out behind the missile as it flies, to a gunner securely hidden in a defiladed launch vehicle. The gunner is able to select the target on a video screen and lock on an autotracker or alternately manually track the target to impact. The system design would use a common warhead for either armor or helicopter targets. The system is currently mounted on the High Mobility, Multipurpose Wheeled Vehicle (HMMWV), containing the gunner's station, launcher, and flight missiles. The gunner's station includes the capability for detailed mission planning, digital map display based on the Defense Mapping Agency's digital map databases, and display of the air battle situation for the gunner. Automatic targeting, control of multiple missiles in the air simultaneously, navigation using a digital correlator, and autotracking of moving targets in cluttered backgrounds with gunner selectable offset tracking capability are also available. The system has a capability to train the gunner using a perspective view scene generator that mimics the video scene he would be presented during missile flight. The scene generator uses the same hardware that displays the digital map, while a simulation of the missile runs in one of the system's computer processors to accurately move the seeker presentation around the scene. All of the other hardware used in embedded training is the same as the actual firing hardware. The system concept has been chosen by the Army as the non-line-of-sight (NLOS) component of the Forward Area Air Defense System (FAADS). The initial design is being upgraded for the MIL SPEC environment to allow early operational

  17. The theoretical analysis of the Fog removal in the LNG Ambient Vaporizer

    NASA Astrophysics Data System (ADS)

    Lee, T.; Lee, D.; Jeong, H.; Chung, H.

    2015-09-01

    The fog removal process is one of the important process in LNG Ambient Vaporizer. In this study we carried out theoretical study of the fog removal process in LNG Ambient Vaporizer. The LNG Ambient Vaporizer in Incheon area was used in our study. The fog temperature and the required energy produced from air fan to remove fog in LNG Ambient Vaporizer were calculated using average temperature of Incheon area in 2012 by Psychometruc Chart method. As a result we can be remove fog in LNG Ambient Vaporizer using Enthalpy[kW] energy in summer season and Enthalpy[kW] in winter season respectively.

  18. Effects of acid rain on grapevines

    SciTech Connect

    Forsline, P.L.; Musselman, R.C.; Dee, R.J.; Kender, W.J.

    1983-01-01

    Mature vineyard-growing Concord grapevines (Vitis labrusca, Bailey) were sprayed with simulated acid rain solutions ranging from pH 2.5 to pH 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, eight additional varieties were also treated with simulated acid rain solutions at pH 2.75 and pH 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids in the absence of acid rain leaf lesions at pH>2.5 remains unclear. Acute sprays (pH 2.75) at anthesis reduced pollen germination in four grape cultivars. However, fruit set was reduced in only one of these. Only the cultivars de Chaunac and Ives had reduced berry soluble solids with chronic weekly sprays at pH 2.75. Reduction in soluble solids was not associated with increased oxidant stipple (ozone injury) in Concord and de Chaunac cultivars, but this association was observed in Ives. There was no evidence that acid rain in combination with ozone increased oxidant stipple as occurs when ozone and SO/sub 2/ are combined. Grape yields were not influenced by acid rain treatments. There was no evidence that acid rain at ambient pH levels had negative effects on grape production or fruit quality.

  19. Effects of acid rain on grapevines

    SciTech Connect

    Forsline, P.L.; Musselman, R.C.; Dee, R.J.; Kender, W.J.

    1983-01-01

    Mature vineyard-growing Concord grapevines were sprayed with simulated acid rain solutions ranging from pH 2.5 to 5.5 both as acute treatments at anthesis and chronically throughout the season in 1980 and 1981. In 1981, 8 additional varieties were also treated with simulated acid rain solutions at pH 2.75 and 3.25. With Concord in 1981, few foliar lesions on leaves were visible at pH 2.75. In contrast, many leaf lesions with decreased fruit soluble solids were observed at pH 2.5 in 1980. The relationship between acid-rain and oxidant stipple, chlorosis, and soluble solids in the absence of acid rain leaf lesions at pH>2.5 remains unclear. Acute sprays (pH2.75) at anthesis reduced pollen germination in four grape cultivars. However, fruit set was reduced in only one of these. Grape yields were not influenced by acid rain treatments. There was no evidence that acid-rain at ambient pH levels had negative effects on grape production or fruit quality.

  20. Clearing the Cosmic Fog - The Most Distant Galaxy Ever Measured

    NASA Astrophysics Data System (ADS)

    2010-10-01

    A European team of astronomers using ESO's Very Large Telescope (VLT) has measured the distance to the most remote galaxy so far. By carefully analysing the very faint glow of the galaxy they have found that they are seeing it when the Universe was only about 600 million years old (a redshift of 8.6). These are the first confirmed observations of a galaxy whose light is clearing the opaque hydrogen fog that filled the cosmos at this early time. The results were presented at an online press conference with the scientists on 19 October 2010, and will appear in the 21 October issue of the journal Nature. "Using the ESO Very Large Telescope we have confirmed that a galaxy spotted earlier using Hubble is the most remote object identified so far in the Universe" [1], says Matt Lehnert (Observatoire de Paris) who is lead author of the paper reporting the results. "The power of the VLT and its SINFONI spectrograph allows us to actually measure the distance to this very faint galaxy and we find that we are seeing it when the Universe was less than 600 million years old." Studying these first galaxies is extremely difficult. By the time that their initially brilliant light gets to Earth they appear very faint and small. Furthermore, this dim light falls mostly in the infrared part of the spectrum because its wavelength has been stretched by the expansion of the Universe - an effect known as redshift. To make matters worse, at this early time, less than a billion years after the Big Bang, the Universe was not fully transparent and much of it was filled with a hydrogen fog that absorbed the fierce ultraviolet light from young galaxies. The period when the fog was still being cleared by this ultraviolet light is known as the era of reionisation [2]. Despite these challenges the new Wide Field Camera 3 on the NASA/ESA Hubble Space Telescope discovered several robust candidate objects in 2009 [3] that were thought to be galaxies shining in the era of reionisation. Confirming the

  1. Acidic Depositions: Effects on Wildlife and Habitats

    USGS Publications Warehouse

    1993-01-01

    The phenomenon of 'acid rain' is not new; it was recognized in the mid-1800s in industrialized Europe. In the 1960s a synthesis of information about acidification began in Europe, along with predictions of ecological effects. In the U.S. studies of acidification began in the 1920s. By the late 1970s research efforts in the U.S. and Canada were better coordinated and in 1980 a 10-year research program was undertaken through the National Acid Precipitation Assessment Plan (NAPAP) to determine the causes and consequences of acidic depositions. Much of the bedrock in the northeastern U.S. and Canada contains total alkalinity of 20 kg/ha/yr of wet sulphate depositions and are vulnerable to acidifying processes. Acidic depositions contribute directly to acidifying processes of soil and soil water. Soils must have sufficient acid-neutralizing capacity or acidity of soil will increase. Natural soil-forming processes that lead to acidification can be accelerated by acidic depositions. Long-term effects of acidification are predicted, which will reduce soil productivity mainly through reduced availability of nutrients and mobilization of toxic metals. Severe effects may lead to major alteration of soil chemistry, soil biota, and even loss of vegetation. Several species of earthworms and several other taxa of soil-inhabiting invertebrates, which are important food of many vertebrate wildlife species, are affected by low pH in soil. Loss of canopy in declining sugar maples results in loss of insects fed on by certain neotropical migrant bird species. No definitive studies categorically link atmospheric acidic depositions with direct or indirect effects on wild mammals. Researchers have concentrated on vegetative and aquatic effects. Circumstantial evidence suggests that effects are probable for certain species of aquatic-dependent mammals (water shrew, mink, and otter) and that these species are at risk from the loss of foods or contamination of these foods by metals

  2. Partitioning of metals between the aqueous phase and suspended insoluble material in fog droplets.

    PubMed

    Mancinelli, Valeriana; Decesari, Stefano; Facchini, Maria Cristina; Fuzzi, Sandro; Mangani, Filippo

    2005-05-01

    This paper discusses the partitioning of metals (K, Na, Ca, Mg, Al, Cu, Fe, Pb and Zn) between the aqueous phase and the suspended insoluble material in fog samples collected in the Po Valley during two extensive fields campaigns. Metals represent on average 11% of the mass of suspended insoluble matter, while the main component is carbon (both organic carbon, OC = 35%, and black carbon, BC = 8%). The unaccounted suspended matter mass is very high, on average 46%, and is attributable to non metallic species, such as O and N and of Si. The principal metals in the insoluble suspended fraction are Fe and Al (2-5%), while the contributions of other metals (Na, Mg, Cu, Pb and Zn) are lower than 1%. Ca and K exhibited high blank values and could not be detected above blank detection limit threshold. The main components in the aqueous phase are NO3- (34%), WSOC (23%), SO4(2-) (18%) and NH4+ (19%), while trace metals and remaining cations and anions accounted for less than 1% of solute mass. The main dissolved trace metals in fog droplets are Zn, Al and Fe, while the main metallic cations are Na and Ca. Fe and Al are the only metals preferentially distributed in the suspended insoluble matter of fog droplets (partitioning ratio respectively 37% and 33%). All other metals are mostly dissolved in the aqueous phase (mean partitioning ratios of Mg, Pb, Zn, Cu and Na are 69%, 70%, 77%, 81% and 87%). These findings are in agreement with literature data on metal speciation in cloud and rain samples. The dependence of partitioning ratios on pH is investigated for the different metals, with only Al showing a clear partitioning ratio decrease with increasing pH. Conversely, the other metals show no dependence or a complex and highly variable behaviour. The partitioning ratio of iron (mean 37%) observed in the Po Valley fog samples is much higher than the water extractable iron in aerosol particles (typically 1-2 %): this fact can be explained by differences in the aerosol sources

  3. Polymer matrix effects on acid generation

    NASA Astrophysics Data System (ADS)

    Fedynyshyn, Theodore H.; Goodman, Russell B.; Roberts, Jeanette

    2008-03-01

    We have measured the acid generation efficiency with EUV exposure of a PAG in different polymer matrixes representing the main classes of resist polymers as well as some previously described fluoropolymers for lithographic applications. The polymer matrix was found to have a significant effect on the acid generation efficiency of the PAG studied. A linear relationship exists between the absorbance of the resist and the acid generation efficiency. A second inverse relationship exists between Dill C and aromatic content of the resist polymer. It was shown that polymer sensitization is important for acid generation with EUV exposure and the Dill C parameter can be increased by up to five times with highly absorbing non-aromatic polymers, such as non-aromatic fluoropolymers, over an ESCAP polymer. The increase in the Dill C value will lead to an up to five fold increase in resist sensitivity. It is our expectation that these insights into the nature of polymer matrix effects on acid generation could lead to increased sensitivity for EUV resists.

  4. Non-human primate FOG develops with advanced parkinsonism induced by MPTP Treatment.

    PubMed

    Revuelta, Gonzalo J; Uthayathas, Subramaniam; Wahlquist, Amy E; Factor, Stewart A; Papa, Stella M

    2012-10-01

    Freezing of gait (FOG) is a debilitating feature of Parkinson's disease (PD) and other forms of parkinsonism. The anatomical or pathophysiological correlates are poorly understood largely due to the lack of a well-established animal model. Here we studied whether FOG is reproduced in the non-human primate (NHP) model of PD. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys (Genus Macaca, n=29) were examined for the development of FOG, and the leg movements were recorded with accelerometry. The relationships between developing FOG and the animals' characteristics, the MPTP treatments, and the modeled outcomes were determined. In parkinsonian monkeys FOG developed frequently (48%) manifesting similar characteristics to those seen in PD patients. In addition, FOG episodes in the monkey were accompanied by leg trembling with the typical duration (2-10s) and frequency (~7 Hz). The development of NHP FOG was significantly associated with the severity of parkinsonism, as shown by high motor disability scores (≥ 20) and levodopa-induced dyskinesia scores (p=0.01 and p=0.04, respectively). Differences in demographics and MPTP treatments (doses, treatment duration, etc.) had no influence on NHP FOG occurrence, with the exception of gender that showed FOG predominance in males (p=0.03). The unique features of FOG in PD can be replicated in severely parkinsonian macaques, and this represents the first description of a FOG animal model.

  5. SUMOylation regulates the transcriptional repression activity of FOG-2 and its association with GATA-4.

    PubMed

    Perdomo, José; Jiang, Xing-Mai; Carter, Daniel R; Khachigian, Levon M; Chong, Beng H

    2012-01-01

    Friend of GATA 2 (FOG-2), a co-factor of several GATA transcription factors (GATA-4, -5 and 6), is a critical regulator of coronary vessel formation and heart morphogenesis. Here we demonstrate that FOG-2 is SUMOylated and that this modification modulates its transcriptional activity. FOG-2 SUMOylation occurs at four lysine residues (K324, 471, 915, 955) [corrected]. Three of these residues are part of the characteristic SUMO consensus site (ψKXE), while K955 is found in the less frequent TKXE motif. Absence of SUMOylation did not affect FOG-2's nuclear localization. However, mutation of the FOG-2 SUMOylation sites, or de-SUMOylation, with SENP-1 or SENP-8 resulted in stronger transcriptional repression activity in both heterologous cells and cardiomyocytes. Conversely, increased FOG-2 SUMOylation by overexpression of SUMO-1 or expression of a SUMO-1-FOG-2 fusion protein rendered FOG-2 incapable of repressing GATA-4-mediated activation of the B-type natriuretic peptide (BNP) promoter. Moreover, we demonstrate both increased interaction between a FOG-2 SUMO mutant and GATA-4 and enhanced SUMOylation of wild-type FOG-2 by co-expression of GATA-4. These data suggest a new dynamics in which GATA-4 may alter the activity of FOG-2 by influencing its SUMOylation status.

  6. An innovative artificial fog production device improved in the European project “FOG”

    NASA Astrophysics Data System (ADS)

    Colomb, M.; Hirech, K.; André, P.; Boreux, J. J.; Lacôte, P.; Dufour, J.

    2008-03-01

    Transport safety is a major goal in the European Union. Low visibility conditions, especially due to fog, increase the risk of major accidents (chain collision). Innovative products have been developed by the automotive industry, including equipment manufacturers, to increase the level of safety of car passengers and drivers. Testing of these products requires the simulation or artificial reproduction of low visibility (fog) conditions with good stability and reproducibility characteristics. We report on the results of the European Union funded "FOG" project to improve road transport safety through fog production in an experimental test chamber located at the Clermont-Ferrand laboratory for research on road safety and visibility. The project developed a prototype of a small-scale climatic chamber, an improved fog production spraying device, a laser-based visibility measurement device, a reduced scale transmissometer, and a combined indoor climate-fog production simulation software. The ability of the fog chamber to test for driver reaction was also investigated. Recent developments include a device able to produce stable visibility levels and homogeneous fog, representative of various types of natural water droplet distribution. The fog characteristics were determined and compared to natural fog. Results are presented for a selection of conditions including stabilized visibility levels for dense fog and two kinds of droplet distributions.

  7. Real-time WAMI streaming target tracking in fog

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Blasch, Erik; Chen, Ning; Deng, Anna; Ling, Haibin; Chen, Genshe

    2016-05-01

    Real-time information fusion based on WAMI (Wide-Area Motion Imagery), FMV (Full Motion Video), and Text data is highly desired for many mission critical emergency or security applications. Cloud Computing has been considered promising to achieve big data integration from multi-modal sources. In many mission critical tasks, however, powerful Cloud technology cannot satisfy the tight latency tolerance as the servers are allocated far from the sensing platform, actually there is no guaranteed connection in the emergency situations. Therefore, data processing, information fusion, and decision making are required to be executed on-site (i.e., near the data collection). Fog Computing, a recently proposed extension and complement for Cloud Computing, enables computing on-site without outsourcing jobs to a remote Cloud. In this work, we have investigated the feasibility of processing streaming WAMI in the Fog for real-time, online, uninterrupted target tracking. Using a single target tracking algorithm, we studied the performance of a Fog Computing prototype. The experimental results are very encouraging that validated the effectiveness of our Fog approach to achieve real-time frame rates.

  8. Vegetation pattern formation in a fog-dependent ecosystem.

    PubMed

    Borthagaray, Ana I; Fuentes, Miguel A; Marquet, Pablo A

    2010-07-01

    Vegetation pattern formation is a striking characteristic of several water-limited ecosystems around the world. Typically, they have been described on runoff-based ecosystems emphasizing local interactions between water, biomass interception, growth and dispersal. Here, we show that this situation is by no means general, as banded patterns in vegetation can emerge in areas without rainfall and in plants without functional root (the Bromeliad Tillandsia landbeckii) and where fog is the principal source of moisture. We show that a simple model based on the advection of fog-water by wind and its interception by the vegetation can reproduce banded patterns which agree with empirical patterns observed in the Coastal Atacama Desert. Our model predicts how the parameters may affect the conditions to form the banded pattern, showing a transition from a uniform vegetated state, at high water input or terrain slope to a desert state throughout intermediate banded states. Moreover, the model predicts that the pattern wavelength is a decreasing non-linear function of fog-water input and slope, and an increasing function of plant loss and fog-water flow speed. Finally, we show that the vegetation density is increased by the formation of the regular pattern compared to the density expected by the spatially homogeneous model emphasizing the importance of self-organization in arid ecosystems. PMID:20417646

  9. 2. Fog signal house and light tower, view west southwest, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Fog signal house and light tower, view west southwest, southeast and northeast sides of signal house, east and north sides of tower - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

  10. 1. Light tower and fog signal house, view south southeast, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Light tower and fog signal house, view south southeast, east and north sides of tower, northeast and northwest sides of signal house - Libby Island Light Station, At southern tip of Libby Island at entrance to Machias Bay, Machiasport, Washington County, ME

  11. Readability and Audience Response: Unfogging the Fog Indexes.

    ERIC Educational Resources Information Center

    Kent, Thomas L.

    Writers and writing teachers should be wary of depending on readability indexes as indicators of the difficulty of written messages. The Gunning Fog Index and the Damerst Clear Index, two readability formulas, were used to determine the readability of "A Statement of Editorial Policy" and two abstracts appearing in an issue of "PMLA." Although the…

  12. Ecosystemic Complexity Theory of Conflict: Understanding the Fog of Conflict

    ERIC Educational Resources Information Center

    Brack, Greg; Lassiter, Pamela S.; Hill, Michele B.; Moore, Sarah A.

    2011-01-01

    Counselors often engage in conflict mediation in professional practice. A model for understanding the complex and subtle nature of conflict resolution is presented. The ecosystemic complexity theory of conflict is offered to assist practitioners in navigating the fog of conflict. Theoretical assumptions are discussed with implications for clinical…

  13. DISCOVERY OF FOG AT THE SOUTH POLE OF TITAN

    SciTech Connect

    Brown, M. E.; Smith, A. L.; Chen, C.; Adamkovics, M.

    2009-11-20

    While Saturn's moon Titan appears to support an active methane hydrological cycle, no direct evidence for surface-atmosphere exchange has yet appeared. The indirect evidence, while compelling, could be misleading. It is possible, for example, that the identified lake features could be filled with ethane, an involatile long-term residue of atmospheric photolysis; the apparent stream and channel features could be ancient remnants of a previous climate; and the tropospheric methane clouds, while frequent, could cause no rain to reach the surface. We report here the detection of fog at the south pole of Titan during late summer using observations from the VIMS instrument on board the Cassini spacecraft. While terrestrial fog can form from a variety of causes, most of these processes are inoperable on Titan. Fog on Titan can only be caused by evaporation of nearly pure liquid methane; the detection of fog provides the first direct link between surface and atmospheric methane. Based on the detections presented here, liquid methane appears widespread at the south pole of Titan in late southern summer, and the hydrological cycle on Titan is currently active.

  14. Dangerous Fog Analyses and Forecast in the Maceio Airport, Brasil

    NASA Astrophysics Data System (ADS)

    Fedorova, N.; Silva, A.; Levit, V.; Santos, E.

    2010-07-01

    A small airplane fatal accident has occurred near Maceio Airport, on the coastal region on 26 July 2007. Low visibility in the intensive fog has provoked this accident. Weather forecast analysis, published in the local and central Brazilian newspapers during 2007, showed fog forecast absence during whole year. A study of the fog formation causes was elaborated using the high and low resolution satellite data, radar data, different products of NCEP reanalysis data and high resolution regional MM5 model simulation. The trade winds with a weak cyclonic curvature at the low levels have generated the humidity convergence at the superficial layers up to 850hPa on the coastal region. An anticyclonic circulation existence at the middle and higher levels and weak ascendant motion (by NCEP data) have support a weak convection development. The low levels clouds development on the continental region and convection development over ocean were confirmed by the radar and satellite data. A thermal inversion near surface level (up to 150m) and descendent movement at the middle and high levels were identified by MM5 model. Fog formation was simulated by PAFOG model. The conventional airport observations have shown the minimal visibility of 200m between 4 and 7a.m. Moreover visibility less than 1000m between 1 and 8a.m. with the minimal visibility of 213m was simulated by PAFOG model.

  15. Polycyclic Aromatic Hydrocarbons Transformations in an Urban Fog

    NASA Astrophysics Data System (ADS)

    Valsaraj, K.; Wornat, M. J.; Chen, J.; Ehrenhauser, F.

    2010-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are generated from incomplete combustion of fuels, coal-fired power plants and other anthropogenic activities. These are ubiquitous in all environments, especially the atmosphere. PAHs generally are found in the gaseous form and associated with the particles in the atmosphere. They are also found in the atmospheric water present in the form of fog, mist, rain, snow and ice. Particles (aerosols) in the atmosphere invariably contain a thin film of water which tends to have a high affinity for the adsorption of gaseous PAHs. Molecular dynamic simulations clearly show that the air-water interface is a preferable surface for adsorption of large molecular weight PAHs and atmospheric oxidants (e.g., O3, OH, 1O2, NO3). Thus, photochemical transformation of adsorbed PAHs in fog droplets is a possibility in the atmosphere. This could lead to the formation of water-soluble oxy-PAHs which are potential precursors for secondary organic aerosols (SOAs). Field work in Baton Rouge and Houston combined with laboratory work in thin film reactors have shown that this hypothesis is substantially correct. Field data on fog and aerosols (pre- and post-fog) will be enumerated. Laboratory work and their implications will be summarized. The thin film surface environment resulted in enhanced reaction kinetics compared to bulk phase kinetics. The influence of surface reactions on the product compositions is evaluated by performing experiments with different film thicknesses.

  16. Vegetation pattern formation in a fog-dependent ecosystem.

    PubMed

    Borthagaray, Ana I; Fuentes, Miguel A; Marquet, Pablo A

    2010-07-01

    Vegetation pattern formation is a striking characteristic of several water-limited ecosystems around the world. Typically, they have been described on runoff-based ecosystems emphasizing local interactions between water, biomass interception, growth and dispersal. Here, we show that this situation is by no means general, as banded patterns in vegetation can emerge in areas without rainfall and in plants without functional root (the Bromeliad Tillandsia landbeckii) and where fog is the principal source of moisture. We show that a simple model based on the advection of fog-water by wind and its interception by the vegetation can reproduce banded patterns which agree with empirical patterns observed in the Coastal Atacama Desert. Our model predicts how the parameters may affect the conditions to form the banded pattern, showing a transition from a uniform vegetated state, at high water input or terrain slope to a desert state throughout intermediate banded states. Moreover, the model predicts that the pattern wavelength is a decreasing non-linear function of fog-water input and slope, and an increasing function of plant loss and fog-water flow speed. Finally, we show that the vegetation density is increased by the formation of the regular pattern compared to the density expected by the spatially homogeneous model emphasizing the importance of self-organization in arid ecosystems.

  17. In vitro pollen responses of two birch species to acidity and temperature

    SciTech Connect

    Hughes, R.N.; Cox, R.M.

    1993-10-01

    Paper birch (Betula papyrifera Marsh.) and mountain paper birch (Betula cordifolia Regel) near the Bay of Fundy coast frequently intercept acidic advection marine fogs. Chemical deposition by these fogs is thought to be a factor contributing to the observed foliar browning symptoms associated with a marked deterioration of these trees in the area. In vitro experiments were performed to test whether pollen germination in these two birch species would be affected by acidity at levels routinely found in the fog. The combined effect of temperature with acidity was also examined. Pollen germination in both species was inhibited below pH 5.6 (P < 0.0001) and the effect of incubation temperature was also significant (P < 0.01) in both species. There was no difference in in vitro pollen germination between species (P > 0.05) in response to acidity, based on combined data from 12 trees of each; the optimum germination temperature was 22{degrees}C for B. papyrifera and 21{degrees}C for B. cordifolia.

  18. Using Multi-Isotope Tracer Methods to Understand the Sources of Nitrate in Aerosols, Fog and River Water in Podocarpus National Forest, Ecuador

    NASA Astrophysics Data System (ADS)

    Brothers, L. A.; Dominguez, G.; Fabian, P.; Thiemens, M. H.

    2008-12-01

    The eastern slopes of the Andean rainforests of Ecuador possess some of the highest plant biodiversity found on the planet; however, these ecosystems are in jeopardy because region is experiences one of the highest deforestation rates in South America. This rainforest characterized by high acidity and low nutrient soils and experiences natural process which are both destabilizing and stabilizing to biodiversity rendering this a unique, though sensitive environment. There is increased concern that anthropogenic activities especially biomass burning are affecting the rainforests and could lead to higher extinction rates, changes in the biodiversity and far reaching effects on the global troposphere. Measurements of nitrate and sulfate in rain and fog water have shown periods of elevated concentrations in the Podocarpus National Park near Loja, Ecuador. These high episodes contribute to annual deposition rates that are comparable to polluted regions of North America and Europe. Significant anthropogenic sources such as large scale industry or a major city, near this forest are lacking. It is believed that the majority of the nitrate and sulfate pollution is due to the large amount of biomass burning during the dry season in the Amazon Basin. In recent years it has been shown that large amount of dust is transported across the Atlantic from Africa which reaches South America. Concentration measurements do not elucidate the source of high nitrate and sulfate pollution; however, by measuring all three stable isotopes of oxygen in nitrate and sulfate from fog and river water provides a new way to examine the impacts of biomass burning on the region. By using stable isotope techniques atmospheric nitrate and sulfate can be resolved from terrestrial sources. This provides a unique way to trace the contributions from the biomass burning and farming sources. Current research at the field station, Estación Científica San Francisco in the Podocarpus National Forest monitors

  19. Potential human health effects of acid rain

    SciTech Connect

    Not Available

    1984-01-01

    Adverse human health effects, namely acute and chronic respiratory effects, can occur from the pre-deposition phase of the acid rain phenomenon due to inhalation of acidic particles and gases. State-of-the-art methodology to evaluate these effects is just now being applied to this question. The major post-deposition effect of the acid rain phenomenon is to acidify water, increasing solubility and subsequent human exposure to mercury, lead, cadmium, and aluminum. Acidification increases bioconversion of mercury to methylmercury, a highly toxic compound, which accumulates in fish, increasing the risk to toxicity in people who eat fish. Increase in water and soil content of lead and cadmium increases human exposure to these metals which become additive to other sources presently under regulatory control. The potential adverse health effects of increased human exposure to aluminum is not known at the present time. Deficiencies in the identification of the contribution of pre-deposition of air pollutants and post-deposition mobilization of toxic metals to the recognized potential health effects of the involved toxic substances is due to the fact that scientists have not addressed these specific questions. 113 references, 4 figures, 2 tables.

  20. Photoformation of Triplet Excited States and Other Oxidants in Fog Waters and Their Impact on Fog Processing of Organic Compounds

    NASA Astrophysics Data System (ADS)

    Kaur, R.; Anastasio, C.; Valsaraj, K. T.; Vempati, H. S.; Vaitilingom, M.

    2014-12-01

    Reactions in fog and cloud drops are important for a number of processes, such as formation of secondary organic aerosol (SOA), cycling of organic carbon and nitrogen, and determining the lifetimes of pollutants. The rates of these processes depend upon the steady-state concentrations of the major photooxidants, namely, hydroxyl radical (.OH), singlet molecular oxygen (1O2*) and triplet excited states of organic compounds (3C*). While there are some past measurements of .OH and 1O2* concentrations in fog and cloud drops, there are no data for the concentrations of triplet excited states. However, there is increasing evidence that triplets might be important for the processing of organics in a cloudy or foggy atmosphere. To address this question, we collected fog water samples from Davis, CA and Baton Rouge, LA, illuminated them with simulated sunlight, and measured the steady-state concentrations of .OH , 1O2* and 3C* . To understand the relative importance of these photooxidants, we also measured the photochemical loss of two added model organic compounds in the illuminated fog waters - syringol (a biomass burning phenol) and methyl jasmonate (a green leaf volatile). Our results show that triplet excited states can play a major role in oxidizing the model compounds, typically accounting for 30 - 90% of the loss of both model compounds. Given that atmospheric triplets are relatively less understood, our results highlight the importance of deeper investigation into their nature.

  1. Distinct Effects of Sorbic Acid and Acetic Acid on the Electrophysiology and Metabolism of Bacillus subtilis

    PubMed Central

    van Beilen, J. W. A.; Teixeira de Mattos, M. J.; Hellingwerf, K. J.

    2014-01-01

    Sorbic acid and acetic acid are among the weak organic acid preservatives most commonly used to improve the microbiological stability of foods. They have similar pKa values, but sorbic acid is a far more potent preservative. Weak organic acids are most effective at low pH. Under these circumstances, they are assumed to diffuse across the membrane as neutral undissociated acids. We show here that the level of initial intracellular acidification depends on the concentration of undissociated acid and less on the nature of the acid. Recovery of the internal pH depends on the presence of an energy source, but acidification of the cytosol causes a decrease in glucose flux. Furthermore, sorbic acid is a more potent uncoupler of the membrane potential than acetic acid. Together these effects may also slow the rate of ATP synthesis significantly and may thus (partially) explain sorbic acid's effectiveness. PMID:25038097

  2. Effects of acidic precipitation on field crops

    SciTech Connect

    Evans, L.S.; Hendrey, G.R.; Lewin, K.F.; Gmur, N.F.

    1982-02-01

    The effects of acid rain on yields of field-grown soybeans has been investigated. Plants exposed to simulated rainfalls of pH 4.1, 3,3 and 2.7 had decreased seed yields of 10.6, 16.8 and 23.9% below yields of plants exposed to simulated rainfalls of pH 5.6. (ACR)

  3. Effects of acid rain on crops and trees

    SciTech Connect

    Cowling, E.B.; Dochinger, L.S.

    1984-01-01

    A general treatment of the subject of acid rain and its effets are discussed along with sources of acid rain and its near-term (the last couple of decades). The effects of acid rain on terrestrial ecosystems are treated in some detail. Some treatment is given of the ecosystem-level effects of acid precipitation.

  4. Methylmercury and other chemical constituents in Pacific coastal fog water from seven sites in Central/Northern California (FogNet) during the summer of 2014

    NASA Astrophysics Data System (ADS)

    Weiss-Penzias, P. S.; Heim, W. A.; Fernandez, D.; Coale, K. H.; Oliphant, A. J.; Dann, D.; Porter, M.; Hoskins, D.; Dodge, C.

    2014-12-01

    This project investigates the mercury content in summertime Pacific coastal fog in California and whether fog could be an important vector for ocean emissions of mercury to be deposited via fog drip to upland coastal ecosystems. Efforts began in early 2014 with the building of 7 active-strand fog collectors based on the Colorado State University Caltech CASCC design. The new UCSC CASCC includes doors sealing the collector which open under microcomputer control based on environmental sensing (relative humidity). Seven sites spanning from Trinidad in the north to Marina in the south have collected samples June-August 2014 under a project called FogNet. Fog conditions were favorable for collecting large water volumes (> 250 mL) at many sites. Fog samplers were cleaned with soap and deionized water daily and field blanks taken immediately following cleaning. Fog water samples were collected overnight, split into an aliquot for anion and DOC/DIC analysis and the remaining sample was acidified. Monomethyl mercury (MMHg) concentrations in samples and field blanks for 3 sites in FogNet are shown in the accompanying figure. The range of MMHg concentrations from 10 fog water samples > 100 mL in volume was 0.9-9.3 ng/L (4.5-46.4 pM). Elevated MMHg concentrations (> 5 ng/L, 25 pM) were observed at 2 sites: UC Santa Cruz and Bodega Bay. The field blanks produced MMHg concentrations of 0.08-0.4 ng/L (0.4-2.0 pM), which was on average < 10% of the sample concentration and suggests the artifact due to sampling was small. The observed MMHg concentrations in fog water observed is this study are 1-2 orders of magnitude greater than MMHg concentrations seen previously in rain water samples from the California coast suggesting an additional source of MMHg to fog. Shipboard measurements of dimethyl mercury (DMHg) in coastal California seawater during the time period of FogNet operations (summer 2014) reveal surface waters that were supersaturated in DMHg which represents a potential

  5. Effects of alkali or acid treatment on the isomerization of amino acids.

    PubMed

    Ohmori, Taketo; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

    2012-10-01

    The effect of alkali treatment on the isomerization of amino acids was investigated. The 100×D/(D+L) values of amino acids from peptide increased with increase in the number of constituent amino acid residues. Furthermore, the N-terminal amino acid of a dipeptide was isomerized to a greater extent than the C-terminal residue.

  6. Investigation of pitch and angle in the gradual-triangle lenticular lens for point-blank LED fog lamp.

    PubMed

    Chen, Hsi-Chao; Yang, Chi-Hao

    2014-05-10

    The effects of different pitch and angle of gradual-triangle lenticular lens for the point-blank LED fog lamp were investigated under the standard of ECE R19. The novel LED fog lamp was assembled from a point-blank LED light source, a parabolic reflector, and a gradual-triangle lenticular lens. Light tracing analysis was used for the design of the gradual-triangle lenticular lens. The pitch, which varied from 1 to 6 mm, and the apex angle, which changed from 5 to 32 deg, were both investigated in regard to the gradual-triangle lenticular lens. The optimum pitch was 5 mm, and the efficiency of the lamp system and lenticular lens could reach 93% and 98.1% by simulation, respectively. The results of experiment had over 94%, which is similar to that of simulation by normalized cross correlation (NCC) for the light intensity.

  7. Comprehensive characterization of atmospheric organic matter in Fresno, California fog water

    USGS Publications Warehouse

    Herckes, P.; Leenheer, J.A.; Collett, J.L.

    2007-01-01

    Fogwater collected during winter in Fresno (CA) was characterized by isolating several distinct fractions and characterizing them by infrared and nuclear magnetic resonance (NMR) spectroscopy. More than 80% of the organic matter in the fogwater was recovered and characterized. The most abundant isolated fractions were those comprised of volatile acids (24% of isolated carbon) and hydrophilic acids plus neutrals (28%). Volatile acids, including formic and acetic acid, have been previously identified as among the most abundant individual species in fogwater. Recovered hydrophobic acids exhibited some properties similar to aquatic fulvic acids. An insoluble particulate organic matter fraction contained a substantial amount of biological material, while hydrophilic and transphilic fractions also contained material suggestive of biotic origin. Together, these fractions illustrate the important contribution biological sources make to organic matter in atmospheric fog droplets. The fogwater also was notable for containing a large amount of organic nitrogen present in a variety of species, including amines, nitrate esters, peptides, and nitroso compounds. ?? 2007 American Chemical Society.

  8. Connections Between Cold Air Pools and Mountain Valley Fog Events in Salt Lake City

    NASA Astrophysics Data System (ADS)

    Chachere, Catherine N.; Pu, Zhaoxia

    2016-05-01

    The aim of this study is to investigate the connection between cold air pools and fog events in Salt Lake City, Utah, United States. Statistical analyses are conducted using soundings and reported automated surface observing system data from Salt Lake International Airport for the last eighteen cold seasons (October to March, during 1997-2015). A Chi-square test of independence is performed on identified cold air pool, and fog events to determine whether the two events are correlated. Conditional probabilities are then computed to investigate the occurrence of fog, given the presence of a cold pool. These probabilities are compared against that of random fog generation in the mid-winter. It is concluded that the dependence between cold air pools and fog events is statistically significant. The presence of a cold pool makes the formation of fog more likely than random generation.

  9. A kind of integrated method discuss of fOG signal processing circuit

    NASA Astrophysics Data System (ADS)

    Lu, Jun; Pan, Xin; Ying, Jiaju; Liu, Jie

    2014-12-01

    In view of the circuit miniaturization need in project application of fiber optic gyroscope(FOG), a new integrated technical scheme adopting system in package(SIP) for signal processing circuit of FOG was put forward. At first, the principle on signal processing circuit of FOG was analyzed, and the technical scheme adopting SIP based on low-temperature co-fired substrate technology was presented according to circuit characteristic and actual condition. Secondly, under the prerequisite of the concept introduction of SIP and LTCC, the SIP prototype of signal processing circuit of FOG was trialed produced,and it passed through the debug test. This SIP modular is an overall circuit complete integrated the signal processing circuit of FOG, and only a potentiometer and EPROM do not case outside. The testing results indicate that SIP is a kind of feasible scheme that carries out miniaturization for signal processing circuit of FOG.

  10. Connections Between Cold Air Pools and Mountain Valley Fog Events in Salt Lake City

    NASA Astrophysics Data System (ADS)

    Chachere, Catherine N.; Pu, Zhaoxia

    2016-09-01

    The aim of this study is to investigate the connection between cold air pools and fog events in Salt Lake City, Utah, United States. Statistical analyses are conducted using soundings and reported automated surface observing system data from Salt Lake International Airport for the last eighteen cold seasons (October to March, during 1997-2015). A Chi-square test of independence is performed on identified cold air pool, and fog events to determine whether the two events are correlated. Conditional probabilities are then computed to investigate the occurrence of fog, given the presence of a cold pool. These probabilities are compared against that of random fog generation in the mid-winter. It is concluded that the dependence between cold air pools and fog events is statistically significant. The presence of a cold pool makes the formation of fog more likely than random generation.

  11. N-nitrosodimethylamine occurrence, formation and cycling in clouds and fogs.

    PubMed

    Hutchings, James W; Ervens, Barbara; Straub, Derek; Herckes, Pierre

    2010-11-01

    The occurrence, source, and sink processes of N-nitrosodimethylamine (NDMA) have been explored by means of combined laboratory, field, and model studies. Observations have shown the occurrence of NDMA in fogs and clouds at substantial concentrations (7.5-397 ng L(-1)). Laboratory studies were conducted to investigate the formation of NDMA from nitrous acid and dimethylamine in the homogeneous aqueous phase. While NDMA was produced in the aqueous phase, the low yields (<1%) observed could not explain observational concentrations. Therefore gaseous formation of NDMA with partitioning to droplets likely dominates aqueous NDMA formation. Box-model calculations confirmed the predominant contributions from gas phase formation followed by partitioning into the cloud droplets. Measurements and model calculations showed that while NDMA is eventually photolyzed, it might persist in the atmosphere for hours after sunrise and before sunset since the photolysis in the aqueous phase might be much less efficient than in the gas phase.

  12. Effect of organic acids on shrimp pathogen, Vibrio harveyi.

    PubMed

    Mine, Saori; Boopathy, Raj

    2011-07-01

    Shrimp farming accounts for more than 40% of the world shrimp production. Luminous vibriosis is a shrimp disease that causes major economic losses in the shrimp industry as a result of massive shrimp kills due to infection. Some farms in the South Asia use antibiotics to control Vibrio harveyi, a responsible pathogen for luminous vibriosis. However, the antibiotic-resistant strain was found recently in many shrimp farms, which makes it necessary to develop alternative pathogen control methods. Short-chain fatty acids are metabolic products of organisms, and they have been used as food preservatives for a long time. Organic acids are also commonly added in feeds in animal husbandry, but not in aquaculture. In this study, growth inhibitory effects of short-chain fatty acids, namely formic acid, acetic acid, propionic acid, and butyric acid, on V. harveyi were investigated. Among four acids, formic acid showed the strongest inhibitory effect followed by acetic acid, propionic acid, and butyric acid. The minimum inhibitory concentration (MIC) of 0.035% formic acid suppressed growth of V. harveyi. The major inhibitory mechanism seems to be the pH effect of organic acids. The effective concentration 50 (EC50) values at 96 h inoculation for all organic acids were determined to be 0.023, 0.041, 0.03, and 0.066% for formic, acetic, propionic, and butyric acid, respectively. The laboratory study results are encouraging to formulate shrimp feeds with organic acids to control vibrio infection in shrimp aquaculture farms.

  13. Laser Imaging Video Camera Sees Through Fire, Fog, Smoke

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Under a series of SBIR contracts with Langley Research Center, inventor Richard Billmers refined a prototype for a laser imaging camera capable of seeing through fire, fog, smoke, and other obscurants. Now, Canton, Ohio-based Laser Imaging through Obscurants (LITO) Technologies Inc. is demonstrating the technology as a perimeter security system at Glenn Research Center and planning its future use in aviation, shipping, emergency response, and other fields.

  14. Ground ULV and thermal fog applications against Phlebotomine sand fly vectors of Leishmania in a hot arid environment in western Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phlebotomine sand fly vectors of Leishmania continue to threaten US military operations in Africa, Southwest Asia, and the Middle East. Ultra-low volume (ULV) and/or thermal fog pesticide dispersal are potentially effective against sand flies, but operational guidance is thinly based on mosquito con...

  15. Dense fog on the highway: Visual range monitoring in cars?

    NASA Technical Reports Server (NTRS)

    Hahn, W.; Krichbaumer, W.; Streicher, J.; Werner, CH.

    1992-01-01

    This paper reports on the development of a new sensor. Laser range-finders are currently installed in cars and trucks to measure the distance to a proceeding car (LEICA). A modification of such a sensor to measure visibility was made. The problems that had to be solved were: (1) choice of wavelength with relation to the human eye for visibility measurements; (2) dependency of the wavelength on atmospheric turbidity; (3) laser eye-safety; and (4) influence of multiple scattering at visibilities smaller than 200 m. The wavelength used for lidar sensors in the near infrared presents no real problems because the object to be sensed is fog appearing white which means that scattering from fog is wavelength independent. There are however differences in backscatter-to-extinction ratio for different fog and weather situations. The two solutions to these problems are polarization and multiple scattering. As known from airport operations of a laser ceilometer, one can use this multiple scattering contribution to determine the visibility.

  16. Dew, fog, drizzle and rain water in Baku (Azerbaijan)

    NASA Astrophysics Data System (ADS)

    Meunier, D.; Beysens, D.

    2016-09-01

    Dwindling supplies of fresh water and climate changes have drawn attention to the need to find alternative sources of water globally. This study examines the potential of the semi-arid region of Baku (Azerbaijan) to exploit in particular dew, but also fog, drizzle and rain water. The Absheron Peninsular suffers from scarceness of water and non-hazardous water sources. Measurements were taken in this region on a 30° inclined plane passive condenser over a year (1/4/2010-31/3/2011) to determine the contribution and validity of using these alternative sources of water. The results show a significant relative contribution from these sources during this period (rain: 84 mm; dew: 15 mm; fog: 6 mm; drizzle: 13 mm). The fact that rain was measured within 23 km from the main station leads to uncertainties in its relative contribution. However, at least for the year under study, there are fair indications that collecting dew, fog and drizzle in addition to rain can significantly increase the collected atmospheric water with value estimated on order 40% ± 20%.

  17. Out of the fog: Catalyzing integrative capacity in interdisciplinary research.

    PubMed

    Piso, Zachary; O'Rourke, Michael; Weathers, Kathleen C

    2016-04-01

    Social studies of interdisciplinary science investigate how scientific collaborations approach complex challenges that require multiple disciplinary perspectives. In order for collaborators to meet these complex challenges, interdisciplinary collaborations must develop and maintain integrative capacity, understood as the ability to anticipate and weigh tradeoffs in the employment of different disciplinary approaches. Here we provide an account of how one group of interdisciplinary fog scientists intentionally catalyzed integrative capacity. Through conversation, collaborators negotiated their commitments regarding the ontology of fog systems and the methodologies appropriate to studying fog systems, thereby enhancing capabilities which we take to constitute integrative capacity. On the ontological front, collaborators negotiated their commitments by setting boundaries to and within the system, layering different subsystems, focusing on key intersections of these subsystems, and agreeing on goals that would direct further investigation. On the methodological front, collaborators sequenced various methods, anchored methods at different scales, validated one method with another, standardized the outputs of related methods, and coordinated methods to fit a common model. By observing the process and form of collaborator conversations, this case study demonstrates that social studies of science can bring into critical focus how interdisciplinary collaborators work toward an integrated conceptualization of study systems.

  18. Numerical Simulations of Diurnal Variation in Martian Surface Fogs

    NASA Astrophysics Data System (ADS)

    Inada, A.; Markiewicz, W. J.

    2001-11-01

    A one-dimensional model of the formation and evolution of the Martian surface fogs is presented. The model includes the micro-physical processes of coagulation, heterogeneous nucleation, condensation, and sublimation. It simulates the diurnal variations in the radii of ice-coated particles and hence the water ice volume on the particles within a 1 km thick layer near the surface. The temperature and pressure profiles used are obtained from the European Martian Climate Database (Forget et al., 1999, JGR, 104, 24155). The places of the Pathfinder landing site (19.2N, 33.2W) and the Memnonia region (15.0S, 145.0W) where the surface fogs were imaged by Viking Orbiter 1 were selected for the simulations. Although the vertical water vapor profile is not well known, the recent data from the Imager for the Mars Pathfinder indicate that the mixing ratio can be as high as 600 ppm in the near surface layer of 1 to 3 km. The dependence of fog formation on the value of this mixing ratio is also discussed. This research was carried out under partial support of JSPS Research Fellowships for Young Scientists.

  19. [Microphysics of atmospheric aerosols during winter haze/fog events in Nanjing].

    PubMed

    Yang, Jun; Niu, Zhong-qing; Shi, Chun-e; Liu, Duan-yang; Li, Zi-hua

    2010-07-01

    Intensive field observations of fog/haze events, including simultaneous measurements of aerosol particle and fog droplet size distributions, were conducted in Nanjing in November, 2007. Four weather conditions (fog, mist, wet haze and haze) were distinguished based on visibility and liquid water content firstly. Then, the microphysical characteristics of coarse and fine particles in each condition were investigated. The results showed the dominant sequence of the four weather conditions was haze<-->mist-->wet haze-->fog-->, wet haze-->mist<-->haze. The lasting time of pre-fog wet haze was longer than that of post-fog wet haze. The number, surface area and volume concentration of coarse particles with diameter larger than 2.0 micron in fog were much higher than those in the other three conditions, and the smallest concentrations were observed in haze. The size distributions of surface area and volume concentration exhibited multi-peak in fog droplets, while it showed single peak for coarse particles in haze, mist and wet haze. For the fine particles with diameter larger than 0.010 microm, the spectral shapes of surface area concentration are similar in fog (mist) and wet haze (haze) condition. The dominant size ranges of fine particle number concentration were in 0.04-0.13 microm and 0.02-0.14 microm for fog and wet haze, separately. The same dominant size ranges located in 0.02-0.06 microm for both mist and haze. During the transition processes from haze, mist and wet haze to fog, the concentration of smaller particles (less than 0.060-0.090 microm) reduced and vice versa for the corresponding larger particles. Temporal variation of aerosol number concentration correlated well with the root mean diameters negatively during the observation period. The number concentration of aerosol was the lowest and the mean diameter was the largest in fog periods.

  20. Large-scale Changes in Marine Fog in a Warmer Climate

    NASA Astrophysics Data System (ADS)

    Kawai, H.; Koshiro, T.; Endo, H.

    2015-12-01

    Marine fog especially over the mid-latitude ocean is an important target in climate simulation because it affects maritime traffic in human lives and the sky obscuring marine fog is a contributor to the earth radiation budget due to its significant coverage. The purpose of the present study is to reveal global-scale changes in marine fog in a warmer climate. The changes in marine fog with climate change are investigated using AMIP, AMIP4K (where a uniform +4 K SST is added to the AMIP SSTs), and AMIPfuture (where a patterned SST perturbation is added to the AMIP SSTs) experiment data simulated by the MRI-CGCM3 (Yukimoto et al. 2012), which was used for CMIP5 runs. First, the representation of the fog in the model was examined using ship observation data and cloud mask data retrieved from CALIPSO satellite data (Kawai et al. 2015). The comparison showed that the MRI-CGCM3 can represent the climatological global distribution of marine fog relatively well. Basically marine fog represented by the model is warm air advection fog, and it was found that the change in the horizontal temperature advection near the surface mostly determines the changes in marine fog in a warmer climate. Therefore, the changes in marine fog can be almost explained by the large-scale circulation changes. On the other hand, in-cloud LWC (liquid water content) of the fog is consistently increased in a warmer climate for the same horizontal surface temperature advection. The changes in mid-latitude marine fog in both the northern and southern hemispheres and for both summer and winter seasons are discussed in connection with the large-scale circulation changes.

  1. Fatty acid effects on fibroblast cholesterol synthesis

    SciTech Connect

    Shireman, R.B.; Muth, J.; Lopez, C.

    1987-05-01

    Two cell lines of normal (CRL 1475, GM5565) and of familial hypercholesterolemia (FH) (CM 486,488) fibroblasts were preincubated with medium containing the growth factor ITS, 2.5 mg/ml fatty acid-free BSA, or 35.2 ..mu..mol/ml of these fatty acids complexed with 2.5 mg BSA/ml: stearic (18:0), caprylic (8:0), oleic (18:1;9), linoleic (18:2;9,12), linolenic (18:3;9,12,15), docosahexaenoic (22:6;4,7,10,13,16,19)(DHA) or eicosapentaenoic (20:5;5,8,11,14,17)(EPA). After 20 h, cells were incubated for 2 h with 0.2 ..mu..Ci (/sup 14/C)acetate/ml. Cells were hydrolyzed; an aliquot was quantitated for radioactivity and protein. After saponification and extraction with hexane, radioactivity in the aqueous and organic phases was determined. The FH cells always incorporated 30-90% more acetate/mg protein than normal cells but the pattern of the fatty acid effects was similar in both types. When the values were normalized to 1 for the BSA-only group, cells with ITS had the greatest (/sup 14/C)acetate incorporation (1.45) followed by the caprylic group (1.14). Cells incubated with 18:3, 20:6 or 22:6 incorporated about the same amount as BSA-only. Those preincubated with 18:2, 18:1, 18:0 showed the least acetate incorporation (0.87, 0.59 and 0.52, respectively). The percentage of total /sup 14/C counts which extracted into hexane was much greater in FH cells; however, these values varied with the fatty acid, e.g., 1.31(18:0) and 0.84(8:0) relative to 1(BSA).

  2. Studies of the effect of gibberellic acid on algal growth.

    NASA Technical Reports Server (NTRS)

    Evans, W. K.; Sorokin, C.

    1971-01-01

    The effect of gibberellic acid on exponential growth rate of four strains of Chlorella was investigated under variety of experimental conditions. In concentrations from 10 ppm to 100 ppm, gibberellic acid was shown to have no effect on Chlorella growth. In concentration of 200 ppm, gibberellic acid exerted some unfavorable effect on algal growth.

  3. The greenhouse effect and acid rain

    SciTech Connect

    Traeger, R.K.

    1990-01-01

    The concentrations of carbon dioxide, methane, sulfur dioxide, nitrous oxides and chlorofluorocarbons is increasing in the earth's atmosphere. Increased concentrations of these trace gases could lead to global warming, increased acid rain and increased UV radiation on the earth's surface; however, the actual impacts are still uncertain and are also the subject of great debate. Application of clean'' energy sources such as geothermal are obviously desirable for decreasing these effects and improving our overall general environment. This paper briefly summarizes the global environment concerns, providing a backdrop for the following papers which describe the geothermal role in future environmental considerations. 5 refs., 2 figs., 1 tab.

  4. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production. PMID:26658985

  5. Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-03-01

    In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

  6. Understanding fog-plant interactions at the ecosystem scale using atmospheric carbonyl sulfide

    NASA Astrophysics Data System (ADS)

    Campbell, J. E.; Whelan, M.; Stinecipher, J.; Zumkehr, A. L.; Berry, J. A.; Dawson, T. E.; Seibt, U.; Hilton, T. W.; Kulkarni, S.; Commane, R.; Angevine, W. M.; Lu, Y.; Herndon, S. C.; Zahniser, M. S.

    2015-12-01

    Ecosystem metabolism is thought to have powerful feedbacks with the climate system as well as direct impacts on individual taxa that rely on ecosystems for food, water, and shelter. Despite the importance of an ecosystem level understanding, climate change impacts on whole ecosystems remains highly uncertain. In particular, coastal fog-dominated regions are a blind spot for whole ecosystem measurements of the land-air-sea exchange of carbon, water, and energy. To address this critical knowledge gap, our inter-displicary team from the University of California's new Institute for the Study of Ecological Effects of Climate Impacts (ISEECI) has launched a next-generation monitoring program along a gradient of UC Natural Reserve System (NRS) sites. We leverage recent breakthroughs in atmospheric spectroscopy and mechanistic ecosystem models of carbonyl sulfide that provide an unprecedented opportunity to explore the sustainability of coastal systems. Here we present our next-generation monitoring and regional analysis across a North/South transect of UC-NRS sites that has the potential to provide a new window into fog-dominated ecosystems, both currently and under climate change scenarios.

  7. Impact of haze-fog days to radon progeny equilibrium factor and discussion of related factors.

    PubMed

    Hou, Changsong; Shang, Bing; Zhang, Qingzhao; Cui, Hongxing; Wu, Yunyun; Deng, Jun

    2015-11-01

    The equilibrium factor F between radon and its short-lived progenies is an important parameter to estimate radon exposure of humans. Therefore, indoor and outdoor concentrations of radon and its short-lived radon progeny were measured in Beijing area using a continuously measuring device, in an effort to obtain information on the F value. The results showed that the mean values of F were 0.58 ± 0.13 (0.25-0.95, n = 305) and 0.52 ± 0.12 (0.31-0.91, n = 64) for indoor and outdoor, respectively. The indoor F value during haze-fog days was higher than the typical value of 0.4 recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation, and it was also higher than the values of 0.47 and 0.49 reported in the literature. A positive correlation was observed between indoor F values and PM2.5 concentrations (R (2) = 0.71). Since 2013, owing to frequent heavy haze-fog events in Beijing and surrounding areas, the number of the days with severe pollution remains at a high level. Future studies on the impact of the ambient fine particulate matter on indoor radon progeny equilibrium factor F could be important. PMID:26143065

  8. Impact of haze-fog days to radon progeny equilibrium factor and discussion of related factors.

    PubMed

    Hou, Changsong; Shang, Bing; Zhang, Qingzhao; Cui, Hongxing; Wu, Yunyun; Deng, Jun

    2015-11-01

    The equilibrium factor F between radon and its short-lived progenies is an important parameter to estimate radon exposure of humans. Therefore, indoor and outdoor concentrations of radon and its short-lived radon progeny were measured in Beijing area using a continuously measuring device, in an effort to obtain information on the F value. The results showed that the mean values of F were 0.58 ± 0.13 (0.25-0.95, n = 305) and 0.52 ± 0.12 (0.31-0.91, n = 64) for indoor and outdoor, respectively. The indoor F value during haze-fog days was higher than the typical value of 0.4 recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation, and it was also higher than the values of 0.47 and 0.49 reported in the literature. A positive correlation was observed between indoor F values and PM2.5 concentrations (R (2) = 0.71). Since 2013, owing to frequent heavy haze-fog events in Beijing and surrounding areas, the number of the days with severe pollution remains at a high level. Future studies on the impact of the ambient fine particulate matter on indoor radon progeny equilibrium factor F could be important.

  9. Real-time assessment of fog-related crashes using airport weather data: a feasibility analysis.

    PubMed

    Ahmed, Mohamed M; Abdel-Aty, Mohamed; Lee, Jaeyoung; Yu, Rongjie

    2014-11-01

    The effect of reduction of visibility on crash occurrence has recently been a major concern. Although visibility detection systems can help to mitigate the increased hazard of limited-visibility, such systems are not widely implemented and many locations with no systems are experiencing considerable number of fatal crashes due to reduction in visibility caused by fog and inclement weather. On the other hand, airports' weather stations continuously monitor all climate parameters in real-time, and the gathered data may be utilized to mitigate the increased risk for the adjacent roadways. This study aims to examine the viability of using airport weather information in real-time road crash risk assessment in locations with recurrent fog problems. Bayesian logistic regression was utilized to link six years (2005-2010) of historical crash data to real-time weather information collected from eight airports in the State of Florida, roadway characteristics and aggregate traffic parameters. The results from this research indicate that real-time weather data collected from adjacent airports are good predictors to assess increased risk on highways.

  10. Occult precipitation as an input to the small catchment: observation, evaluation and new technics of fog water collection in the Czech Republic

    NASA Astrophysics Data System (ADS)

    Tesar, M.; Fisak, J.; M., Sir; Bartunkova, K.

    2010-07-01

    the 16-years period proved high acidity of fog water and high values of enrichment factors. The compounds NH4+, SO42- and NO3- are the dominant species both in fog water and in precipitation. In order to collect cloud water samples, the active and passive sample-taking devices were constructed. Besides the collectors, as described in literature, both passive and active fog water collectors of the new design were developed and installed at the selected localities.

  11. Catheter for Cleaning Surgical Optics During Surgical Procedures: A Possible Solution for Residue Buildup and Fogging in Video Surgery.

    PubMed

    de Abreu, Igor Renato Louro Bruno; Abrão, Fernando Conrado; Silva, Alessandra Rodrigues; Corrêa, Larissa Teresa Cirera; Younes, Riad Nain

    2015-05-01

    Currently, there is a tendency to perform surgical procedures via laparoscopic or thoracoscopic access. However, even with the impressive technological advancement in surgical materials, such as improvement in quality of monitors, light sources, and optical fibers, surgeons have to face simple problems that can greatly hinder surgery by video. One is the formation of "fog" or residue buildup on the lens, causing decreased visibility. Intracavitary techniques for cleaning surgical optics and preventing fog formation have been described; however, some of these techniques employ the use of expensive and complex devices designed solely for this purpose. Moreover, these techniques allow the cleaning of surgical optics when they becomes dirty, which does not prevent the accumulation of residue in the optics. To solve this problem we have designed a device that allows cleaning the optics with no surgical stops and prevents the fogging and residue accumulation. The objective of this study is to evaluate through experimental testing the effectiveness of a simple device that prevents the accumulation of residue and fogging of optics used in surgical procedures performed through thoracoscopic or laparoscopic access. Ex-vivo experiments were performed simulating the conditions of residue presence in surgical optics during a video surgery. The experiment consists in immersing the optics and catheter set connected to the IV line with crystalloid solution in three types of materials: blood, blood plus fat solution, and 200 mL of distilled water and 1 vial of methylene blue. The optics coupled to the device were immersed in 200 mL of each type of residue, repeating each immersion 10 times for each distinct residue for both thirty and zero degrees optics, totaling 420 experiments. A success rate of 98.1% was observed after the experiments, in these cases the device was able to clean and prevent the residue accumulation in the optics.

  12. Spectral properties of fog over the Malaspina Glacier, Alaska, in comparison to snow, ice, and clouds

    NASA Technical Reports Server (NTRS)

    Ormsby, James P.; Hall, Dorothy D.

    1991-01-01

    Analysis of Landsat 5 Thematic Mapper (TM) data of the Malaspina Glacier in southeastern Alaska has shown that fog overlying the glacier ice has reflectance characteristics similar to the ice below and that the spectral reflectance of fog can be different from other types of clouds. Fog is more reflective in the visible and near-infrared wavelengths compared to snow, ice, and cumulus clouds. The differentiation between clouds, fog, and the ice below can be enhanced by combining TM bands in the visible part of the spectrum.

  13. Vertical distribution of microphysical properties in radiation fogs - A case study

    NASA Astrophysics Data System (ADS)

    Egli, S.; Maier, F.; Bendix, J.; Thies, B.

    2015-01-01

    The present study investigates the validity of a theoretical liquid water content (LWC) profile in fog layers currently used for satellite based ground fog detection, with a special focus on the temporal dynamics during fog life cycle. For this purpose, LWC profiles recorded during two different fog events by means of a tethered balloon borne measurement system are presented and discussed. The results indicate a good agreement in trend and gradient between measured and theoretical LWC profiles during the mature stage of the fog life cycle. The profile obtained during the dissipation stage shows less accordance with the theoretical profile. To improve the agreement between theoretical and measured LWC profiles, the evolutionary stages during the fog life cycle should be incorporated. However, the variability within the prenoted measurements points out that more LWC profiles during a great variety of different fog events have to be collected for a well-justified adaptation of the theoretical LWC profile, considering fog life cycle phases in the future. In general, this underlines the existing knowledge gap regarding the vertical distribution of microphysical properties in natural fogs.

  14. Two typical boundary layer structures in sea fog on the coast of southern China

    NASA Astrophysics Data System (ADS)

    Huang, H.; Huang, J.; Mao, W.; Bi, X.

    2013-12-01

    Two kinds of sea fog exist on the coast of southern China according to our observations. The predominant one is advection fog. This kind of sea fog has the typical feature that the surface air temperature (SAT) is higher than the sea surface temperature (SST). The formation mechanism is that the eddy diffusion (mechanical turbulence) transports the upper saturation air and liquid water content to the sea surface. The maintain factor is the warm and moist transportation along the thermal turbulence interface. The other kind is the advection-radiative fog, is familiar to the sea fog on the west coast of USA and the Haar. In this kind of fog, the SAT is lower than the SST. This kind of sea fog is initially cooled by contact with the cold sea via advection, and then the mainly maintain mechanism is the radiation from the top of the sea fog and the evaporation from the sea. These two kinds of sea fog are interacted with the low cloud, and could transform from one to the other kind under certain conditions.

  15. Numerical simulation of diurnally varying thermal environment in a street canyon under haze-fog conditions

    NASA Astrophysics Data System (ADS)

    Tan, Zijing; Dong, Jingliang; Xiao, Yimin; Tu, Jiyuan

    2015-10-01

    The impact of haze-fog on surface temperature, flow pattern, pollutant dispersion and pedestrian thermal comfort are investigated using computational fluid dynamics (CFD) approach based on a three-dimensional street canyon model under different haze-fog conditions. In this study, light extinction coefficient (Kex) is adopted to represent haze-fog pollution level. Numerical simulations are performed for different Kex values at four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST). The numerical results suggest that the surface temperature is strongly affected by the haze-fog condition. Surface heating induced by the solar radiation is enhanced by haze-fog, as higher surface temperature is observed under thicker haze-fog condition. Moreover, the temperature difference between sunlit and shadow surfaces is reduced, while that for the two shadow surfaces is slightly increased. Therefore, the surface temperature among street canyon facets becomes more evenly distributed under heavy haze-fog conditions. In addition, flow patterns are considerably altered by different haze-fog conditions, especially for the afternoon (1600 LST) case, in which thermal-driven flow has opposite direction as that of the wind-driven flow direction. Consequently, pollutants such as vehicular emissions will accumulate at pedestrian level, and pedestrian thermal comfort may lower under thicker haze-fog condition.

  16. Processing of atmospheric polycyclic aromatic hydrocarbons by fog in an urban environment.

    PubMed

    Ehrenhauser, Franz S; Khadapkar, Kalindi; Wang, Youliang; Hutchings, James W; Delhomme, Olivier; Kommalapati, Raghava R; Herckes, Pierre; Wornat, Mary J; Valsaraj, Kalliat T

    2012-10-26

    Polycyclic aromatic hydrocarbons (PAH) are ubiquitous pollutants in the atmosphere, predominantly known for their toxicity. Although there has been substantial work on the atmospheric degradation of PAH, little is known about how the presence of atmospheric droplets (e.g., a fog cloud) affects the fate of PAH. In order to assess the processing of PAH and their corresponding oxidation products during a fog event, two field-sampling campaigns in Fresno, CA and Davis, CA were conducted. The simultaneous evaluation of concentrations of the PAH and oxygenated polycyclic aromatic compounds (OPAC) in the gas phase, particulate matter and fog water droplets before, during and after fog allows for the characterization of transformative and transport processes in a fog cloud. By tracking the ratio of OPAC to PAH in the individual atmospheric phases, two major polycyclic aromatic compounds-processing pathways can be identified: (i) the dissolution of OPAC from particulate matter and (ii) the uptake and oxidation of PAH in the fog water droplets. Wet deposition steadily decreases the pollutant concentration in the fog cloud droplets during a fog event; however, uptake and concentration via evaporative water loss upon the dissipation of a fog cloud cause an increase in the atmospheric pollutant concentration.

  17. Daytime sea fog retrieval based on GOCI data: a case study over the Yellow Sea.

    PubMed

    Yuan, Yibo; Qiu, Zhongfeng; Sun, Deyong; Wang, Shengqiang; Yue, Xiaoyuan

    2016-01-25

    In this paper, a new daytime sea fog detection algorithm has been developed by using Geostationary Ocean Color Imager (GOCI) data. Based on spectral analysis, differences in spectral characteristics were found over different underlying surfaces, which include land, sea, middle/high level clouds, stratus clouds and sea fog. Statistical analysis showed that the Rrc (412 nm) (Rayleigh Corrected Reflectance) of sea fog pixels is approximately 0.1-0.6. Similarly, various band combinations could be used to separate different surfaces. Therefore, three indices (SLDI, MCDI and BSI) were set to discern land/sea, middle/high level clouds and fog/stratus clouds, respectively, from which it was generally easy to extract fog pixels. The remote sensing algorithm was verified using coastal sounding data, which demonstrated that the algorithm had the ability to detect sea fog. The algorithm was then used to monitor an 8-hour sea fog event and the results were consistent with observational data from buoys data deployed near the Sheyang coast (121°E, 34°N). The goal of this study was to establish a daytime sea fog detection algorithm based on GOCI data, which shows promise for detecting fog separately from stratus.

  18. 1995 Integrated Monitoring Study: Fog measurements in the Northern San Joaquin Valley - preliminary results

    SciTech Connect

    Collett, J. Jr.; Bator, A.; Sherman, D.E.

    1996-12-31

    Vertical gradients in fog chemistry and physics were measured from a 430 m television broadcast tower in the northern San Joaquin Valley near Walnut Grove, California. Fog was collected on the ground and at two elevations on the tower using Caltech Active Strand Cloudwater Collectors Version 2 (CASCC2). Work was conducted as part of the 1995 Integrated Monitoring Study (IMS95). Results will be used to evaluate the need to make measurements aloft in future regional studies of fog processing of atmospheric particles and for testing whether vertically resolved fog models provide realistic simulations of fog physics and chemistry above the ground. Two fog/low cloud events were sampled during the tower study. Preliminary results show concentrations of major species in the fogwater typically decreasing with altitude, while liquid water contents increase. Fogwater loadings of major species, the total amount of a species in the aqueous phase per unit air volume, were observed to increase with altitude. Major species concentrations were typically quite stable at a given elevation, while significant decreases were observed over time in liquid water content. Fogwater concentrations of soluble hydroperoxides were highest near the surface and increased with time after sunrise and were observed to coexist in the high pH fog with S(IV). Time lapse video footage of the top of the fog/cloud layer revealed a very dynamic interface, suggesting entrainment of material from the clear air into the fog/cloud may be significant. 12 refs., 7 figs.

  19. On Study of Sea Fog over the Yellow and Bohai Seas in China

    NASA Astrophysics Data System (ADS)

    Fu, G.; Gao, S.; Yang, Y.; Xu, X.; Wang, X.; Chen, Y.; Xue, D.; Shen, J.

    2010-07-01

    A ubiquitous feature of the Yellow and Bohai Sea (YBS) in the eastern Asian region is the frequent occurrence of the sea fog in spring and summer season. The pioneer work on sea fog over YBS can be traced back to Prof. Binhua Wang as early as 1940's. He investigated sea fog systematically and published his book Sea Fog in 1985 (by China Ocean Press and Springer-Verlag). Recently, a research group in the Department of Marine Meteorology at Ocean University of China (OUC) continued sea fog research collaborated with Shandong Meteorological Bureau and Qingdao Meteorological Bureau under the financial supports of National Natural Science Foundation of China and China Meteorological Administration. Their researches involved in both observation analyses and high-resolution modeling of sea fog over YBS. In this talk, the brief history of sea fog research in China will be reviewed firstly. Then, a typical heavy sea fog event over YBS occurred in the morning of 11 April 2004 will be documented by using all available observational data and high-resolution Regional Atmospheric Modeling System (RAMS) modeling results. Finally, the applications of a quasi-operational sea fog forecasting system which was mainly based on RAMS model will be introduced.

  20. The influence of microclimates and fog on stable isotope signatures used in interpretation of regional hydrology: East Maui, Hawaii

    USGS Publications Warehouse

    Scholl, M.A.; Gingerich, S.B.; Tribble, G.W.

    2002-01-01

    Stable isotopes of precipitation, ground water and surface water measured on the windward side of East Maui from 0 to 3055 m altitude were used to determine recharge sources for stream flow and ground water. Correct interpretation of the hydrology using rainfall ??18O gradients with altitude required consideration of the influence of fog, as fog samples had isotopic signatures enriched by as much as 3??? in ??18O and 21??? in ??D compared to volume-weighted average precipitation at the same altitude. The isotopic analyses suggested that fog drip was a major component of stream flow and shallow ground water at higher altitudes in the watershed. 18O/altitude gradients in rainfall were comparable for similar microclimates on Maui (this study) and Hawaii Island (1990-1995 study), however, East Maui ??18O values for rain in trade-wind and high-altitude microclimates were enriched compared to those from Hawaii Island. Isotopes were used to interpret regional hydrology in this volcanic island aquifer system. In part of the study area, stable isotopes indicate discharge of ground water recharged at least 1000 m above the sample site. This deep-flowpath ground water was found in springs from sea level up to 240 m altitude, indicating saturation to altitudes much higher than a typical freshwater lens. These findings help in predicting the effects of ground water development on stream flow in the area. Published by Elsevier Science B.V.

  1. [Effects of low molecular weight organic acids on speciation of exogenous Cu in an acid soil].

    PubMed

    Huang, Guo-Yong; Fu, Qing-Ling; Zhu, Jun; Wan, Tian-Ying; Hu, Hong-Qing

    2014-08-01

    In order to ascertain the effect of LMWOA (citric acid, tartaric acid, oxalic acid) on Cu-contaminated soils and to investigate the change of Cu species, a red soil derived from quartz sandstone deposit was added by Cu (copper) in the form of CuSO4 x 5H2O so as to simulate soil Cu pollution, keeping the additional Cu concentrations were 0, 100, 200, 400 mg x kg(-1) respectively. After 9 months, different LMWOA was also added into the simulated soil, keeping the additional LMWOAs in soil were 0, 5, 10, 20 mmol x kg(-1) respectively. After 2 weeks incubation, the modified sequential extraction method on BCR (European Communities Bureau of Reference) was used to evaluate the effects of these LMWOAs on the changes of copper forms in soil. The result showed that the percentage of weak acid dissolved Cu, the most effective form in the soil increased with three organic acids increase in quantity in the simulated polluted soil. And there was a good activation effect on Cu in the soil when organic acid added. Activation effects on Cu increased with concentration of citric acid increasing, but it showed a rise trend before they are basically remained unchanged in the case of tartaric acid and oxalic acid added in the soil. On the contrary, the state of the reduction of copper which was regarded as a complement for effective state decreased with the increased concentration of organic acid in the soil, especially with citric acid. When 20 mmol x kg(-1) oxalic acid and citric acid were added into the soil, the activation effect was the best; whereas for tartaric, the concentration was 10 mmol x kg(-1). In general, the effect on the changes of Cu forms in the soil is citric acid > tartaric acid > oxalic acid.

  2. Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

    PubMed

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-09-01

    An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

  3. Can fog contribute to the nutrition of Chamaecyparis obtusa var. formosana? Uptake of a fog solute tracer into foliage and transport to roots.

    PubMed

    Lai, I-Ling; Schroeder, Walter H; Wu, Jiunn-Tzong; Kuo-Huang, Ling-Long; Mohl, Carola; Chou, Chang-Hung

    2007-07-01

    Yellow cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl. var. formosana (Hayata) Rehder) is the predominant tree species of Taiwan's nutrient-poor, mountain fog forests. Little is known about the potential contribution of solute uptake from fog to the overall nutrition of these trees. Shoots of yellow cypress seedlings were misted with artificial fog containing the tracer rubidium (Rb) in laboratory and field experiments to determine if there is solute uptake from the fog. After misting shoots for six weeks, substantial amounts of tracer were detected in unexposed roots by inductively coupled plasma mass spectroscopy bulk analysis. Possible routes of entry were examined by element imaging with energy dispersive X-ray analysis. Direct uptake of the tracer into leaves across the cuticle and epidermis was small, excluding this as the major uptake path. Accumulations of Rb were found on leaf surfaces along the edges of the leaves. The almost daily changes in fog coverage and air humidity may enhance the accumulation of fog solutes at leaf edges. Accumulation of Rb was also found in narrow clefts between opposite leaves and between the outermost and underlying alternating stacked leaves. The clefts provide a direct passage from the leaf surface to the space beneath the imbricate leaves and the underlying alternate leaves, possibly facilitating solute uptake from fog, which in turn may contribute to the nutrition of yellow cypress. PMID:17403653

  4. Can fog contribute to the nutrition of Chamaecyparis obtusa var. formosana? Uptake of a fog solute tracer into foliage and transport to roots.

    PubMed

    Lai, I-Ling; Schroeder, Walter H; Wu, Jiunn-Tzong; Kuo-Huang, Ling-Long; Mohl, Carola; Chou, Chang-Hung

    2007-07-01

    Yellow cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl. var. formosana (Hayata) Rehder) is the predominant tree species of Taiwan's nutrient-poor, mountain fog forests. Little is known about the potential contribution of solute uptake from fog to the overall nutrition of these trees. Shoots of yellow cypress seedlings were misted with artificial fog containing the tracer rubidium (Rb) in laboratory and field experiments to determine if there is solute uptake from the fog. After misting shoots for six weeks, substantial amounts of tracer were detected in unexposed roots by inductively coupled plasma mass spectroscopy bulk analysis. Possible routes of entry were examined by element imaging with energy dispersive X-ray analysis. Direct uptake of the tracer into leaves across the cuticle and epidermis was small, excluding this as the major uptake path. Accumulations of Rb were found on leaf surfaces along the edges of the leaves. The almost daily changes in fog coverage and air humidity may enhance the accumulation of fog solutes at leaf edges. Accumulation of Rb was also found in narrow clefts between opposite leaves and between the outermost and underlying alternating stacked leaves. The clefts provide a direct passage from the leaf surface to the space beneath the imbricate leaves and the underlying alternate leaves, possibly facilitating solute uptake from fog, which in turn may contribute to the nutrition of yellow cypress.

  5. Effect of chloroacetic acids on the kidneys

    SciTech Connect

    Davis, M.E.

    1986-11-01

    The effects of dichloroacetate (DCA) and trichloroacetate (TCA) administered in drinking water were studied. At high concentrations of either compound, weight loss, or failure to gain weight, was observed. Food consumption was also decreased; both effects were attributed to decreased water consumption. Renal phosphate-dependent glutaminase activity was increased at the highest concentration, and urinary ammonia was also increased. These changes indicated renal adaptation to an acid load. DCA, in pharmacological doses, impairs glucoenogenesis from lactate in part by decreasing lactate availability. Similar tendencies were observed in the present studies; however, female rats showed a biphasic response. At lower DCA concentrations, tissue lactate and plasma glucose concentrations were increased, whereas at higher concentrations of DCA, the expected decreases were observed.

  6. Characterizing Spatial Patterns of Cloud Cover And Fog Inundation in the California Channel Islands

    NASA Astrophysics Data System (ADS)

    Rastogi, B.; Fischer, D. T.; Williams, P.; Iacobellis, S.; McEachern, K.; Still, C. J.

    2013-12-01

    Coastal forests in Mediterranean climates are frequently covered by clouds or immersed in fog. Previous studies suggest that clouds strongly modulate forest distributions as well as carbon and water budgets in these semi-arid environments. Both low level stratocumulus cloud cover and fog can enhance the water status of vegetation along the Californian coast and the Channel Islands by reducing insolation and raising relative humidity and thus reducing evapotranspiration, while also potentially supplying water directly to the landscape from fog-drip during otherwise warm and rainless summers. While cloud cover and fog can ameliorate summer drought stress and enhance soil water budgets, they often have different spatial and temporal patterns. The resulting shifts in relative ecological importance of fog and stratus are largely unknown. The overall objective of this project was to map spatial and temporal distributions of daytime cloud cover frequency for the California Channel Islands, and to predict probabilities of surface cloud (fog) contact and immersion for these islands. Daytime cloud cover maps were generated for the northern Channel Islands using GOES satellite imagery for the years 1996-2012. To discriminate fog from stratus the base of the cloud height was constrained by using airport cloud ceiling data and topographic information. In order to observe variation in fog frequency at scales relevant to species distributions on the Channel Islands the native GOES resolution was downscaled by using radiosonde and reanalysis data. Satellite derived estimates of cloud cover and fog were correlated with field measurements of insolation, fog drip and leaf wetness on Santa Rosa and Santa Cruz islands. This enabled spatial and temporal extrapolation to understand seasonal and inter-annual variations in cloud cover frequency and fog inundation and drip and will be important for future water balance modeling, studies of coastal vegetation distributions and for better

  7. Observation of coastal fogs using a suite of ground based remote sensing instruments

    NASA Astrophysics Data System (ADS)

    Song, J. I.; Yum, S. S.; Kim, K. H.; Kim, Y. H.; Cho, C. H.; Oh, S. B.

    2014-12-01

    Fog is the cloud of which the base is at the earth surface. Because of severely reduced visibility when fog is present, on-road traffics, maritime transport and aircraft operations are often hampered by fog occurrence. Therefore, accurate prediction of fog has been of high priority in traffic safety. The first step towards the accurate prediction of fog would be to detect the fog formation and monitor the evolution of fog in a continuous manner so that we can better characterize the fog formation mechanism. However, observing the evolution of fog has been difficult due to its nature of local meteorological scale and the lack of proper measurement of such scale. In situ measurements can provide us the most accurate data, but these measurements are limited to a very small spatial coverage. Satellite remote sensing can cover a wider spatial scale but detailed structure cannot be detected, In contrast, ground based remote sensing has advantages in spatial and temporal coverages. Here we present the data measured using a suite of ground based remote sensing instruments at the National Center for Intensive Observation of severe weather (NCIO), located at a southern coastal rural town of Boseong, Korea (34.76 ̊ N, 127.16 ̊ E), which include a scanning Ka-band cloud radar, wind profiler, microwave radiometer, ceilometer and lidar. Analysis of these data will be complemented by the basic meteorological (temperature, relative humidity, wind speed and direction) data measured at 11 different altitudes on a 300m meteorological observation tower installed at NCIO. With the sea to the south, the hilly topographical setting to the north, and the ragged coastal line in between, fog formation mechanisms in this region are expected to be very complex. Our eventual goal is to obtain an insight on the formation mechanisms of the coastal fogs in this region through the analysis of these comprehensive dataset. Some preliminary results from this effort will be presented at the

  8. Electrostatic effects on hyaluronic acid configuration

    NASA Astrophysics Data System (ADS)

    Berezney, John; Saleh, Omar

    2015-03-01

    In systems of polyelectrolytes, such as solutions of charged biopolymers, the electrostatic repulsion between charged monomers plays a dominant role in determining the molecular conformation. Altering the ionic strength of the solvent thus affects the structure of such a polymer. Capturing this electrostatically-driven structural dependence is important for understanding many biological systems. Here, we use single molecule manipulation experiments to collect force-extension behavior on hyaluronic acid (HA), a polyanion which is a major component of the extracellular matrix in all vertebrates. By measuring HA elasticity in a variety of salt conditions, we are able to directly assess the contribution of electrostatics to the chain's self-avoidance and local stiffness. Similar to recent results from our group on single-stranded nucleic acids, our data indicate that HA behaves as a swollen chain of electrostatic blobs, with blob size proportional to the solution Debye length. Our data indicate that the chain structure within the blob is not worm-like, likely due to long-range electrostatic interactions. We discuss potential models of this effect.

  9. The Influence of Asian Dust, Haze, Mist, and Fog on Hospital Visits for Airway Diseases

    PubMed Central

    Park, Jinkyeong; Lim, Myoung Nam; Hong, Yoonki

    2015-01-01

    Background Asian dust is known to have harmful effects on the respiratory system. Respiratory conditions are also influenced by environmental conditions regardless of the presence of pollutants. The same pollutant can have different effects on the airway when the air is dry compared with when it is humid. We investigated hospital visits for chronic obstructive pulmonary disease (COPD) and asthma in relation to the environmental conditions. Methods We conducted a retrospective study using the Korean National Health Insurance Service claims database of patients who visited hospitals in Chuncheon between January 2006 and April 2012. Asian dust, haze, mist, and fog days were determined using reports from the Korea Meteorological Administration. Hospital visits for asthma or COPD on the index days were compared with the comparison days. We used two-way case-crossover techniques with one to two matching. Results The mean hospital visits for asthma and COPD were 59.37 ± 34.01 and 10.04 ± 6.18 per day, respectively. Hospital visits for asthma significantly increased at lag0 and lag1 for Asian dust (relative risk [RR], 1.10; 95% confidence interval [CI], 1.01-1.19; p<0.05) and haze (RR, 1.13; 95% CI, 1.06-1.22; p<0.05), but were significantly lower on misty (RR, 0.89; 95% CI, 0.80-0.99; p<0.05) and foggy (RR, 0.89; 95% CI, 0.84-0.93; p<0.05) days than on control days. The hospital visits for COPD also significantly increased on days with Asian dust (RR, 1.29; 95% CI, 1.05-1.59; p<0.05), and were significantly lower at lag4 for foggy days, compared with days without fog (RR, 0.85; 95% CI, 0.75-0.97; p<0.05). Conclusion Asian dust showed an association with airway diseases and had effects for several days after the exposure. In contrast to Asian dust, mist and fog, which occur in humid air conditions, showed the opposite effects on airway diseases, after adjusting to the pollutants. It would require more research to investigate the effects of various air conditions on

  10. LC/TOF-MS Identification of Organic Components in Cloud and Fog Water Samples

    NASA Astrophysics Data System (ADS)

    Rinehart, L. R.; Shen, X.; Collett, J. L.

    2006-12-01

    The nature and identity of organic compounds in cloud and fog droplets are not well understood. Approximately 80 percent of the total organic carbon remains unidentified due to several confounding factors. Traditionally, many of the organic compound analyses have been accomplished by the use of gas chromatography (GC) / mass spectrometry (MS) methods. These methods require analytes to be extracted from water and introduced into the GC by the use of organic solvents. Extraction efficiencies of the water- soluble organic components vary widely depending upon molecular size and polarity. Additionally, many polar compounds are thermally labile and require derivatization to make them more amenable for GC/MS analysis. Liquid chromatography (LC) methods which allow for sample introduction in water have also been used widely for organic analyses. However, commonly used detection methods such as conductivity, UV absorbance, and fluorescence limit the identification of organic components based on detection specific associated physical properties. Recently, electrospray ionization has allowed for MS detection to be paired with LC. There exist several types of MS each with their own specific advantages and disadvantages. In this study, we used LC with accurate mass time of flight (TOF) MS. The distinct advantage of accurate mass TOF is that it may be used to identify unknown organic compounds. Here we present results from our search for novel organic components (including organic nitrogen and organosulfates) in a variety of cloud and fog water samples from polluted and rural environments. These results are paired with established measurement methods for liquid water content, pH, and concentrations of total organic carbon (TOC), dissolved organic carbon (DOC), carbohydrates, formaldehyde, low molecular weight organic acids, carbonyls, and organic nitrogen.

  11. Cosmetotextiles with Gallic Acid: Skin Reservoir Effect

    PubMed Central

    Alonso, Cristina; Martínez, Vanessa; Lis, Manel; de la Maza, Alfons; Parra, José L.; Coderch, Luisa

    2013-01-01

    The antioxidant gallic acid (GA) has been incorporated into cotton (CO) and polyamide (PA) through two different vehicles, that is, liposomes and mixed micelles, and their respective absorption/desorption processes have been studied. Moreover, in vitro percutaneous absorption tests of different cosmetotextiles have been performed to demonstrate antioxidant penetration within the layers of the skin. When GA was embedded into the cosmetotextiles, it always promoted a reservoir effect that was much more marked than that observed for polyamide. Similar penetration was observed in the textiles treated with GA in mixed micelles or liposomes in such compartments of the skin as the stratum corneum, epidermis, and even the dermis. GA was detected in receptor fluid only when CO was treated with MM. This methodology may be useful in verifying how encapsulated substances incorporated into textile materials penetrate human skin. Indeed, such materials can be considered strategic delivery systems that release a given active compound into the skin at specific doses. PMID:23691326

  12. More on Effects Controlling Carboxylic Acidity.

    ERIC Educational Resources Information Center

    Schwartz, Lowell M.

    1981-01-01

    Gas phase acidity data shown are offered to writers of elementary organic chemistry texts for replacement of the aqueous phase data that are universally used. Relative acidities in the gas phase are controlled virtually exclusively by enthalpic factors. Structural-energetic explanations of acidic trends can therefore be used. (SK)

  13. Ethanol Effects On Physiological Retinoic Acid Levels

    PubMed Central

    Napoli, Joseph L.

    2011-01-01

    Summary All-trans-retinoic acid (atRA) serves essential functions during embryogenesis and throughout post-natal vertebrate life. Insufficient or excess atRA causes teratogenic and/or toxic effects in the developing embryo: interference with atRA biosynthesis or signaling likely underlies some forms of cancer. Many symptoms of vitamin A (atRA precursor) deficiency and/or toxicity overlap with those of another pleiotropic agent—ethanol. These overlapping symptoms have prompted research to understand whether interference with atRA biosynthesis and/or action may explain (in part) pathology associated with excess ethanol consumption. Ethanol affects many aspects of retinoid metabolism and mechanisms of action site-specifically, but no robust data support inhibition of vitamin A metabolism, resulting in decreased atRA in vivo during normal vitamin A nutriture. Actually, ethanol either has no effect on or increases atRA at select sites. Despite this realization, insight into whether interactions between ethanol and retinoids represent cause vs. effect requires additional research. PMID:21766417

  14. An Effective Acid Combination for Enhanced Properties and Corrosion Control of Acidizing Sandstone Formation

    NASA Astrophysics Data System (ADS)

    Umer Shafiq, Mian; Khaled Ben Mahmud, Hisham

    2016-03-01

    To fulfill the demand of the world energy, more technologies to enhance the recovery of oil production are being developed. Sandstone acidizing has been introduced and it acts as one of the important means to increase oil and gas production. Sandstone acidizing operation generally uses acids, which create or enlarge the flow channels of formation around the wellbore. In sandstone matrix acidizing, acids are injected into the formation at a pressure below the formation fracturing pressure, in which the injected acids react with mineral particles that may restrict the flow of hydrocarbons. Most common combination is Hydrofluoric Acid - Hydrochloric with concentration (3% HF - 12% HCl) known as mud acid. But there are some problems associated with the use of mud acid i.e., corrosion, precipitation. In this paper several new combinations of acids were experimentally screened to identify the most effective combination. The combinations used consist of fluoboric, phosphoric, formic and hydrofluoric acids. Cores were allowed to react with these combinations and results are compared with the mud acid. The parameters, which are analyzed, are Improved Permeability Ratio, strength and mineralogy. The analysis showed that the new acid combination has the potential to be used in sandstone acidizing.

  15. Ancillary effects of selected acid deposition control policies

    SciTech Connect

    Moe, R.J.; Lyke, A.J.; Nesse, R.J.

    1986-08-01

    NAPAP is examining a number of potential ways to reduce the precursors (sulfur dioxide and nitrogen oxides) to acid deposition. However, the policies to reduce acid deposition will have other physical, biological and economic effects unrelated to acid deposition. For example, control policies that reduce sulfur dioxide emissions may also increase visibility. The effects of an acid deposition policy that are unrelated to acid deposition are referred to as ''ancillary'' effects. This reserch identifies and characterizes the principle physical and economic ancillary effects associated with acid deposition control and mitigation policies. In this study the ancillary benefits associated with four specific acid deposition policy options were investigated. The four policy options investigated are: (1) flue gas desulfurization, (2) coal blending or switching, (3) reductions in automobile emissions of NO/sub x/, and (4) lake liming. Potential ancillary benefits of each option were identified and characterized. Particular attention was paid to the literature on economic valuation of potential ancillary effects.

  16. Drop size distributions and related properties of fog for five locations measured from aircraft

    NASA Technical Reports Server (NTRS)

    Zak, J. Allen

    1994-01-01

    Fog drop size distributions were collected from aircraft as part of the Synthetic Vision Technology Demonstration Program. Three west coast marine advection fogs, one frontal fog, and a radiation fog were sampled from the top of the cloud to the bottom as the aircraft descended on a 3-degree glideslope. Drop size versus altitude versus concentration are shown in three dimensional plots for each 10-meter altitude interval from 1-minute samples. Also shown are median volume radius and liquid water content. Advection fogs contained the largest drops with median volume radius of 5-8 micrometers, although the drop sizes in the radiation fog were also large just above the runway surface. Liquid water content increased with height, and the total number of drops generally increased with time. Multimodal variations in number density and particle size were noted in most samples where there was a peak concentration of small drops (2-5 micrometers) at low altitudes, midaltitude peak of drops 5-11 micrometers, and high-altitude peak of the larger drops (11-15 micrometers and above). These observations are compared with others and corroborate previous results in fog gross properties, although there is considerable variation with time and altitude even in the same type of fog.

  17. Failure of megakaryopoiesis and arrested erythropoiesis in mice lacking the GATA-1 transcriptional cofactor FOG

    PubMed Central

    Tsang, Alice P.; Fujiwara, Yuko; Hom, Dennis B.; Orkin, Stuart H.

    1998-01-01

    GATA transcription factors are required for the differentiation of diverse cell types in several species. Recent evidence suggests that their biologic activities may be modulated through interaction with multitype zinc finger proteins, such as Friend of GATA-1 (FOG) and U-shaped (Ush). In cell culture, FOG cooperates with the hematopoietic transcription factor GATA-1 to promote erythroid and megakaryocytic differentiation. We show here that mice lacking FOG die during mid-embryonic development with severe anemia. FOG−/− erythroid cells display a marked, but partial, blockage of maturation, reminiscent of GATA-1− erythroid precursors. In contrast to GATA-1 deficiency, however, megakaryocytes fail to develop in the absence of FOG. Although the FOG−/− erythroid phenotype supports the proposed role of FOG as a GATA-1 cofactor in vivo, the latter finding points to a pivotal, GATA-1-independent requirement for FOG in megakaryocyte development from the bipotential erythroid/megakaryocytic progenitor. We speculate that FOG and other FOG-like proteins serve as complex cofactors that act through both GATA-dependent and GATA-independent mechanisms. PMID:9553047

  18. Bioinspired conical copper wire with gradient wettability for continuous and efficient fog collection.

    PubMed

    Ju, Jie; Xiao, Kai; Yao, Xi; Bai, Hao; Jiang, Lei

    2013-11-01

    Inspired by the efficient fog collection on cactus spines, conical copper wires with gradient wettability are fabricated through gradient electrochemical corrosion and subsequent gradient chemical modification. These dual-gradient copper wires' fog-collection ability is demonstrated to be higher than that of conical copper wires with pure hydrophobic surfaces or pure hydrophilic surfaces, and the underlying mechanism is also analyzed.

  19. Can we estimate the fog-top height from atmospheric turbulent measurements at surface?

    NASA Astrophysics Data System (ADS)

    Román-Cascón, Carlos; Yagüe, Carlos; Steeneveld, Gert-Jan; Sastre, Mariano; Arrillaga, Jon A.; Maqueda, Gregorio

    2016-04-01

    The knowledge of the fog-top height (fog thickness) can be very meaningful for aircraft maneuvers, data assimilation/validation of Numerical Weather Prediction models or nowcasting of fog dissipation. However, its value is usually difficult to determine and it is sometimes approximated with satellite data, ground remote-sensing instruments or atmospheric soundings. These instruments are expensive and their data not always available. In this work, we show how the fog-top height shows a linear correlation with atmospheric turbulent variables measured close to the surface. This relation is statistically calculated from observational data of several radiation-fog events at two research sites: The Research Centre for the Lower Atmosphere (CIBA) in Spain and the Cabauw Experimental Site for Atmospheric Research (CESAR) in The Netherlands. Thus, surface friction velocity and buoyancy heat flux are presented as potential indicators of fog thickness. These methods are also evaluated over a long-lasting radiation-fog event at CESAR. The proposed methods could be operationally implemented for providing a continuous estimation of fog-top height through the deployment of a sonic anemometer close to the surface.

  20. Factors That Influence Properties of FOG Deposits and Their Formation in Sewer Collection Systems.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages, which eventually lead to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer ...

  1. Fog simulation using a mesoscale model in and around the Yodo River Basin, Japan.

    PubMed

    Hikari, Shimadera; Kundan, Lal Shrestha; Akira, Kondo; Akikazu, Kaga; Yoshio, Inoue

    2008-01-01

    In this study, fog simulations were conducted using the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) in and around the Yodo River Basin, Japan. The purpose is to investigate the MM5 performance of fog simulation for long-term periods. The simulations were performed for January, February, March, and July, 2005 with a coarse 3-km and a nested fine 1-km grid domains. Results of the simulations were compared with data from ten meteorological observatories, fog sampling site in Mt. Rokko, and visibility measurement sites along the Second Meishin Expressway. At the meteorological observatories, the MM5 predictions agreed well with the observed temperature and specific humidity. In the Mt. Rokko region, MM5 generally reproduced the occurrence of relatively thick fog events but tended to overestimate liquid water content (LWC) of fog (by factors of 2.2-3.3 in terms of monthly mean LWC). In the Second Meishin Expressway region, while MM5 identified the specific sites at which fog either frequently or seldom occurs, the model underestimated the monthly fog frequencies by factors of more than 1.5. Overall, MM5 reproduced the general trend of fog events, and the model performance may be improved by using more adequate land surface data and suitable physics options for our study.

  2. 1995 Integrated Monitoring Study: Fog measurements in the Southern San Joaquin Valley - preliminary results

    SciTech Connect

    Collett, J. Jr.; Bator, A.; Sherman, D.E.

    1996-12-31

    Fogs were sampled at three ground-based stations in the southern portion of California`s San Joaquin Valley as part of the winter component of the 1995 Integrated Monitoring Study (IMS95). The three sampling sites included two urban locations (Bakersfield and Fresno) and one rural location (near the Kern Wildlife Refuge). Both bulk and drop size-fractionated samples were collected at each site. Several fog events were sampled, with three periods of extensive fog coverage that included all three sampling sites. Results of preliminary data analysis are presented. Fog collected at the sites was generally quite basic. Most bulk fog samples had pH values above 6 reflecting strong inputs from ammonia. Occasional strong sulfur plumes at Bakersfield, however, tended to lower the fog pH. Aside from these periods, nitrate was generally present at much higher concentrations in the fog than sulfate. Decreases in fogwater loadings of major species over the course of one extended fog episode at Fresno suggest significant deposition was occurring to the surface, consistent with observations of substantial droplet fluxes to exposed surfaces during that period. 16 refs., 7 figs., 1 tab.

  3. Fog and Cloud Induced Aerosol Modification Observed by AERONET

    NASA Technical Reports Server (NTRS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M. A.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Platnick, S. E.; Arnold, G. T.; Krotkov, N. A.; Carn, S. A.; Sinyuk, A.; Dubovik, O.; Arola, A.; Schafer, J. S.; Artaxo, P.; Smirnov, A.; Chen, H.; Goloub, P.

    2011-01-01

    Large fine mode (sub-micron radius) dominated aerosols in size distributions retrieved from AERONET have been observed after fog or low-altitude cloud dissipation events. These column-integrated size distributions have been obtained at several sites in many regions of the world, typically after evaporation of low altitude cloud such as stratocumulus or fog. Retrievals with cloud processed aerosol are sometimes bimodal in the accumulation mode with the larger size mode often approx.0.4 - 0.5 microns radius (volume distribution); the smaller mode typically approx.0.12 to aprrox.0.20 microns may be interstitial aerosol that were not modified by incorporation in droplets and/or aerosol that are less hygroscopic in nature. Bimodal accumulation mode size distributions have often been observed from in situ measurements of aerosols that have interacted with clouds, and AERONET size distribution retrievals made after dissipation of cloud or fog are in good agreement with particle sizes measured by in situ techniques for cloud-processed aerosols. Aerosols of this type and large size range (in lower concentrations) may also be formed by cloud processing in partly cloudy conditions and may contribute to the shoulder of larger size particles in the accumulation mode retrievals, especially in regions where sulfate and other soluble aerosol are a significant component of the total aerosol composition. Observed trends of increasing aerosol optical depth (AOD) as fine mode radius increased suggests higher AOD in the near cloud environment and therefore greater aerosol direct radiative forcing than typically obtained from remote sensing, due to bias towards sampling at low cloud fraction.

  4. Bionic development of textile materials for harvesting water from fog

    NASA Astrophysics Data System (ADS)

    Sarsour, J.; Stegmaier, Th.; Linke, M.; Planck, H.

    2010-07-01

    The supply of drinking water is one of the great challenges for mankind in the future. At present about one billion people have no access to clean drinking water. Particularly in developing countries the supply of potable water is often insufficient. A centralized water supply can often not be implemented because of technical and logistical problems. In certain remote areas, a connection to a public water supply net is economically or technically not feasible, e.g. in settlements on small islands, in isolated sea bays or in mountainous areas. Water supply represents a fundamental problem for terrestrial organisms. In fact, plants and animals of dry areas have developed various methods for obtaining water. The potential for a technical transfer of these natural solutions is far from being well evaluated. An example for obtaining water in arid environments is fog harvesting. Particularly in environments which receive extremely low rates of precipitation, organisms can be found which are capable of obtaining water from fog. The goal of this project is a detailed study of the underlying strategies and mechanisms and their application in technical devices for fog harvesting of drinking water. The project concentrates on the development of textile materials which are optimized for their use in large harvesting collector arrays that are able to supply multi-family houses and/or schools up to smaller villages with water. We expect that techniques can also be used in irrigation systems. The lecture presents the transfer strategy of biological strategies into textile-based devices and first successful field studies.

  5. Atmospheric dispersion of ammonia: an ammonia fog model

    SciTech Connect

    Kansa, E.J.; Rodean, H.C.; Chan, S.T.; Ermak, D.L.

    1983-01-01

    A simplification to the two-phase ammonia vapor-droplet fog problem has been implemented to study the dispersion of a spill of 40 tons of ammonia. We have circumvented the necessity of adding the partial differential equations for mass, momentum, and energy for the ammonia in the liquid phase by certain assumptions. It is assumed that the ammonia fog behaves as an ideal gas including the droplets. A temperature-dependent molecular weight was introduced to simulate the transition from a vapor-droplet cloud to a pure vapor cloud of ammonia. Likewise, the vaporization of ammonia was spread out over a temperature range. Mass, momentum, energy, and total ammonia is conserved rigorously. The observed features of the ammonia spill simulation have pointed out phenomena that could not be predicted in simpler calculations. Perhaps the most obvious feature is the cloud bifurcation due to the strength of the gravity current relative to the ambient wind. The gravity spreading of the denser ammonia fog significantly perturbs the unidirectional windfield in the vicinity of the spill, setting up complex eddy patterns in the cloud which are enhanced by ground heating and warm dry air entrainment. The lower concentrations appear to lift off by a buoyancy-induced flow. The ammonia cloud, rather than being cigar shaped as assumed in simpler models, ranges from pancake shaped to pear shaped, depending upon the ambient windfield. The fact that the ammonia cloud remains cold, very low, and wide is in qualitative agreement with some of the large-scale ammonia spill accidents. 14 figures.

  6. Fog Induced Aerosol Modification Observed by AERONET, Including Occurrences During Major Air Pollution Events

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Li, Z.; Platnick, S. E.; Arnold, T.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.; Kim, J.; Kim, Y. J.; Sinyuk, A.; Dubovik, O.; Arola, A. T.; Schafer, J.; Artaxo, P.; Smirnov, A.; Chen, H.; Goloub, P.

    2014-12-01

    The modification of aerosol optical properties due to interaction with fog is examined from measurements made by sun/sky radiometers at several AERONET sites. Retrieved total column volume size distributions for cases identified as aerosol modified by fog often show very a large 'middle mode' submicron radius (~0.4 to 0.5 microns), which is typically seen as a component of a bimodal sub-micron distribution. These middle mode sized particles are often called cloud-processed or residual aerosol. This bimodal accumulation mode distribution may be due to one mode (the larger one) from fog-processed aerosol and the other from interstitial aerosol, or possibly from two different aerosol species (differing chemical composition) with differing hygroscopic growth factors. The size of the fine mode particles from AERONET retrieved for these cases exceeds the size of sub-micron sized particles retrieved for nearly all other aerosol types, suggesting significant modification of aerosols within the fog or cloud environment. In-situ measured aerosol size distributions made during other fog events are compared to the AERONET retrievals, and show close agreement in the residual mode particle size. Almucantar retrievals are analyzed from the Kanpur site in the Indo-Gangetic Plain in India (fog in January), Beijing (fog in winter), Fresno, CA in the San Joaquin Valley (fog in winter), South Korea (Yellow Sea fog in spring), Arica on the northern coast of Chile (stratocumulus), and several other sites with aerosol observations made after fog dissipated. Additionally, several major air pollution events are discussed where extremely high aerosol concentrations were measured at the surface and during which fog also occurred, resulting in the detection very large fine mode aerosols (residual mode) from AERONET retrievals in some of these events. Low wind speeds that occurred during these events were conducive to both pollutant accumulation and also fog formation. The presence of fog then

  7. FOG-2 mediated recruitment of the NuRD complex regulates cardiomyocyte proliferation during heart development.

    PubMed

    Garnatz, Audrey S; Gao, Zhiguang; Broman, Michael; Martens, Spencer; Earley, Judy U; Svensson, Eric C

    2014-11-01

    FOG-2 is a multi-zinc finger protein that binds the transcriptional activator GATA4 and modulates GATA4-mediated regulation of target genes during heart development. Our previous work has demonstrated that the Nucleosome Remodeling and Deacetylase (NuRD) complex physically interacts with FOG-2 and is necessary for FOG-2 mediated repression of GATA4 activity in vitro. However, the relevance of this interaction for FOG-2 function in vivo has remained unclear. In this report, we demonstrate the importance of FOG-2/NuRD interaction through the generation and characterization of mice homozygous for a mutation in FOG-2 that disrupts NuRD binding (FOG-2(R3K5A)). These mice exhibit a perinatal lethality and have multiple cardiac malformations, including ventricular and atrial septal defects and a thin ventricular myocardium. To investigate the etiology of the thin myocardium, we measured the rate of cardiomyocyte proliferation in wild-type and FOG-2(R3K5A) developing hearts. We found cardiomyocyte proliferation was reduced by 31±8% in FOG-2(R3K5A) mice. Gene expression analysis indicated that the cell cycle inhibitor Cdkn1a (p21(cip1)) is up-regulated 2.0±0.2-fold in FOG-2(R3K5A) hearts. In addition, we demonstrate that FOG-2 can directly repress the activity of the Cdkn1a gene promoter, suggesting a model by which FOG-2/NuRD promotes ventricular wall thickening by repression of this cell cycle inhibitor. Consistent with this notion, the genetic ablation of Cdkn1a in FOG-2(R3K5A) mice leads to an improvement in left ventricular function and a partial rescue of left ventricular wall thickness. Taken together, our results define a novel mechanism in which FOG-2/NuRD interaction is required for cardiomyocyte proliferation by directly down-regulating the cell cycle inhibitor Cdkn1a during heart development.

  8. Fog Induced Aerosol Modification Observed by AERONET, Including Occurrences During Major Air Pollution Events

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Giles, D. M.; Rivas, M.; Singh, R. P.; Tripathi, S. N.; Bruegge, C. J.; Li, Z.; Platnick, S. E.; Arnold, T.; Ferrare, R. A.; Hostetler, C. A.; Burton, S. P.; Kim, J.; Kim, Y. J.; Sinyuk, A.; Dubovik, O.; Arola, A. T.; Schafer, J.; Artaxo, P.; Smirnov, A.; Chen, H.; Goloub, P.

    2015-12-01

    The modification of aerosol optical properties due to interaction with fog is examined from measurements made by sun/sky radiometers at several AERONET sites. Retrieved total column volume size distributions for cases identified as aerosol modified by fog often show very a large 'middle mode' submicron radius (~0.4 to 0.5 microns), which is typically seen as a component of a bimodal sub-micron distribution. These middle mode sized particles are often called cloud-processed or residual aerosol. This bimodal accumulation mode distribution may be due to one mode (the larger one) from fog-processed aerosol and the other from interstitial aerosol, or possibly from two different aerosol species (differing chemical composition) with differing hygroscopic growth factors. The size of the fine mode particles from AERONET retrieved for these cases exceeds the size of sub-micron sized particles retrieved for nearly all other aerosol types, suggesting significant modification of aerosols within the fog or cloud environment. In-situ measured aerosol size distributions made during other fog events are compared to the AERONET retrievals, and show close agreement in the residual mode particle size. Almucantar retrievals are analyzed from the Kanpur site in the Indo-Gangetic Plain in India (fog in January), Beijing (fog in winter), Fresno, CA in the San Joaquin Valley (fog in winter), South Korea (Yellow Sea fog in spring), Arica on the northern coast of Chile (stratocumulus), and several other sites with aerosol observations made after fog dissipated. Additionally, several major air pollution events are discussed where extremely high aerosol concentrations were measured at the surface and during which fog also occurred, resulting in the detection very large fine mode aerosols (residual mode) from AERONET retrievals in some of these events. Low wind speeds that occurred during these events were conducive to both pollutant accumulation and also fog formation. The presence of fog then

  9. Urbanization Causes Increased Cloud Base Height and Decreased Fog in Coastal Southern California

    NASA Technical Reports Server (NTRS)

    Williams, A. Park; Schwartz, Rachel E.; Iacobellis, Sam; Seager, Richard; Cook, Benjamin I.; Still, Christopher J.; Husak, Gregory; Michaelsen, Joel

    2015-01-01

    Subtropical marine stratus clouds regulate coastal and global climate, but future trends in these clouds are uncertain. In coastal Southern California (CSCA), interannual variations in summer stratus cloud occurrence are spatially coherent across 24 airfields and dictated by positive relationships with stability above the marine boundary layer (MBL) and MBL height. Trends, however, have been spatially variable since records began in the mid-1900s due to differences in nighttime warming. Among CSCA airfields, differences in nighttime warming, but not daytime warming, are strongly and positively related to fraction of nearby urban cover, consistent with an urban heat island effect. Nighttime warming raises the near-surface dew point depression, which lifts the altitude of condensation and cloud base height, thereby reducing fog frequency. Continued urban warming, rising cloud base heights, and associated effects on energy and water balance would profoundly impact ecological and human systems in highly populated and ecologically diverse CSCA.

  10. Shifts in microbial communities in bioaugmented grease interceptors removing fat, oil, and grease (FOG).

    PubMed

    He, Xia; So, Mark Jason; de Los Reyes, Francis L

    2016-08-01

    To understand the effect of daily bioaugmentation in full-scale grease interceptors (GIs), we compared the microbial communities occurring in two full-scale GIs during bioaugmented and non-bioaugmented cycles. The changes in microbial communities were determined using terminal restriction fragment length polymorphism (T-RFLP) and 16S rRNA gene clone library construction. Differences in the microbial community structure between control and bioaugmented cycles were observed in all cases, although the dominant terminal restriction fragments in the biological product were not detected. The addition of bioaugmentation products and changes in the GI microbial ecology were related to differences in GI performance. Understanding the shifts due to bioaugmentation will result in more informed assessments of the benefits of bioadditives on FOG removal in GIs as well as the effects on downstream sewer lines.

  11. Urbanization causes increased cloud base height and decreased fog in coastal Southern California

    NASA Astrophysics Data System (ADS)

    Williams, A. Park; Schwartz, Rachel E.; Iacobellis, Sam; Seager, Richard; Cook, Benjamin I.; Still, Christopher J.; Husak, Gregory; Michaelsen, Joel

    2015-03-01

    Subtropical marine stratus clouds regulate coastal and global climate, but future trends in these clouds are uncertain. In coastal Southern California (CSCA), interannual variations in summer stratus cloud occurrence are spatially coherent across 24 airfields and dictated by positive relationships with stability above the marine boundary layer (MBL) and MBL height. Trends, however, have been spatially variable since records began in the mid-1900s due to differences in nighttime warming. Among CSCA airfields, differences in nighttime warming, but not daytime warming, are strongly and positively related to fraction of nearby urban cover, consistent with an urban heat island effect. Nighttime warming raises the near-surface dew point depression, which lifts the altitude of condensation and cloud base height, thereby reducing fog frequency. Continued urban warming, rising cloud base heights, and associated effects on energy and water balance would profoundly impact ecological and human systems in highly populated and ecologically diverse CSCA.

  12. Fog Water Systems in South Africa: An Update.

    NASA Astrophysics Data System (ADS)

    van Heerden, J.; Olivier, J.; van Schalkwyk, L.

    2010-07-01

    This paper reports on fog water harvesting in South Africa. Ten semi-operational fog water catchment systems were erected at rural schools in South Africa between 1999 and 2007. These systems copied the basic design features of the systems at El Tofo, Chili, modified for South African conditions. Major problems were experienced due to poor maintenance and vandalism. Another serious problem was the abrasion of the 40% shade cloth netting against the supporting cables. Gale force winds also led to the complete failure and collapse of the systems. It thus became obvious that the simple flat screen structure is not suitable for South African conditions. Co-operation with Mesh Concepts cc and Cloud Water Concepts cc resulted in the development of a new design for fog/cloud water collection. This design comprises three 40 m2 panels joined together to form the sides of an equilateral triangle. Four such triangles are linked together to form a 9 panel system. The six 6 m poles supporting the 9 panels are 11 m apart and all structure and net support cables are anchored, in line, with the sides of the panels. The system is 5.5 m high and the 9 panel system exposes 360m2 to the cloud/fog. The system is stable and wind forces are transferred to the anchors via nylon pulleys housed in brackets bolted to the poles. The mesh material is a poly yarn co-knitted with stainless steel that provides strength and stability to the mesh. An added advantage is that several 9 panel systems can be linked and expanded to cover the available space. There are currently three such systems in place - at Brook’s Nek (1650 m MSL) in the mountains of the Eastern Cape (684 m2) and at Lamberts Bay and Doring Bay (both 360 m2) on the West Coast. An experimental 3-panel system has been established on the Zondachsberg (1142m MSL), 35 km north of Plettenberg Bay. Preliminary data from this site indicate that orographic cloud forms against the mountain side soon after the wind turns to the south. Average

  13. Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog

    NASA Astrophysics Data System (ADS)

    Elias, T.; Dupont, J.-C.; Hammer, E.; Hoyle, C. R.; Haeffelin, M.; Burnet, F.; Jolivet, D.

    2015-06-01

    The study assesses the contribution of aerosols to the extinction of visible radiation in the mist-fog-mist cycle. Relative humidity is large in the mist-fog-mist cycle, and aerosols most efficient in interacting with visible radiation are hydrated and compose the accumulation mode. Measurements of the microphysical and optical properties of these hydrated aerosols with diameters larger than 0.4 μm were carried out near Paris, during November 2011, under ambient conditions. Eleven mist-fog-mist cycles were observed, with a cumulated fog duration of 96 h, and a cumulated mist-fog-mist cycle duration of 240 h. In mist, aerosols grew by taking up water at relative humidities larger than 93%, causing a visibility decrease below 5 km. While visibility decreased down from 5 to a few kilometres, the mean size of the hydrated aerosols increased, and their number concentration (Nha) increased from approximately 160 to approximately 600 cm-3. When fog formed, droplets became the strongest contributors to visible radiation extinction, and liquid water content (LWC) increased beyond 7 mg m-3. Hydrated aerosols of the accumulation mode co-existed with droplets, as interstitial non-activated aerosols. Their size continued to increase, and some aerosols achieved diameters larger than 2.5 μm. The mean transition diameter between the aerosol accumulation mode and the small droplet mode was 4.0 ± 1.1 μm. Nha also increased on average by 60 % after fog formation. Consequently, the mean contribution to extinction in fog was 20 ± 15% from hydrated aerosols smaller than 2.5 μm and 6 ± 7% from larger aerosols. The standard deviation was large because of the large variability of Nha in fog, which could be smaller than in mist or 3 times larger. The particle extinction coefficient in fog can be computed as the sum of a droplet component and an aerosol component, which can be approximated by 3.5 Nha (Nha in cm-3 and particle extinction coefficient in Mm-1. We observed an influence of

  14. A multi-structural and multi-functional integrated fog collection system in cactus.

    PubMed

    Ju, Jie; Bai, Hao; Zheng, Yongmei; Zhao, Tianyi; Fang, Ruochen; Jiang, Lei

    2012-01-01

    Multiple biological structures have demonstrated fog collection abilities, such as beetle backs with bumps and spider silks with periodic spindle-knots and joints. Many Cactaceae species live in arid environments and are extremely drought-tolerant. Here we report that one of the survival systems of the cactus Opuntia microdasys lies in its efficient fog collection system. This unique system is composed of well-distributed clusters of conical spines and trichomes on the cactus stem; each spine contains three integrated parts that have different roles in the fog collection process according to their surface structural features. The gradient of the Laplace pressure, the gradient of the surface-free energy and multi-function integration endow the cactus with an efficient fog collection system. Investigations of the structure-function relationship in this system may help us to design novel materials and devices to collect water from fog with high efficiencies.

  15. Field evaluation of fog dispersal tests at Elmira, NY: Final report

    SciTech Connect

    Rogers, C.W.; Wattle, B.J.; Mack, E.J.

    1987-06-01

    Calspan Corp., under contract to Energy Innovations, Inc., assisted in tests of the EGD Fog Precipiation System at Elmira/Corning Regional Airport in New York during the summer/fall fog season of 1986 by conducting an independent, objective evaluation of the EGD System during these tests. Specifically, Calspan's role was to: Establish and maintain a network of ground-based visibility monitors and supporting meteorological instrumentation for measuring fog characteristics during EGD System tests at Elmira; provide weather forecasts of the potential for fog at Elmira during the summer-fall fog season; analyze visibility and surface wind velocity measurements to determine the efficacy of the EGD system in producing visibility improvement during dispersal tests; and provide a final independent summary report documenting experiment protocol and the results of Calspan's analyses. 2 refs., 12 figs., 6 tabs.

  16. Comment on comment on ''acid precipitation in historical perspective and effects of acid precipitation''

    SciTech Connect

    Henriksen, A.; Richter, D.D.

    1984-01-01

    The author criticizes the fact that some soil scientists have difficulties in accepting that lakes and stream waters have become acid due to acid rain, because the natural production of acidity in ecosystems is large compared to the contribution from acid rain. He points out that Richter concludes that many of the reported changes, where real, may well result from natural processes with relatively minor contributions from acid precipitation. The author also disagrees with Krug and Frink who recently suggested that SO/sub 4/ from acid rain is exchanged with organic anions originally present in the water, leaving pH essentially unchanged. The author rebuts Henriksen who he says appears to have misunderstood the intent of the original correspondence, which was not to document evidence but rather to assert two generalities; (1) adverse effects of acid deposition on ecosystems are commonly overstated, and (2) the biogeochemistry of ecosystems is easily oversimplified, and natural sources of acidity are often ignored.

  17. Human health effects of exposure to airborne acid.

    PubMed

    Folinsbee, L J

    1989-02-01

    This paper summarizes and critiques a series of reports on the health effects of acid aerosol exposure, presented at the Symposium on the Health Effects of Acid Aerosols and compares these data to selected previous studies. The role of the two major defenses against acid aerosols, the conversion of acid to the ammonium salts by respiratory ammonia and buffering of acid by airway surface liquid are discussed in relation to airway acid burdens expected from typical inhalation exposures. The roles of particle size and hygroscopicity on airway deposition of aerosol are also included. The major health effects studied were the effects of acid aerosol on mucociliary clearance in healthy individuals and changes in lung function in asthmatics, an important sensitive subpopulation. The broad range of response in asthmatics suggests the need for further study.

  18. Bottling Fog? The Quest for Instructional Management

    ERIC Educational Resources Information Center

    Murphy, Joseph; Neumerski, Christine M.; Goldring, Ellen; Grissom, Jason; Porter, Andy

    2016-01-01

    Elsewhere, the authors have unpacked instructional leadership and have documented that such leadership is associated with more effective schools. Indeed, there has been for a considerable time nearly universal acceptance that learning-centered leadership should provide the central platform on which leadership is enacted. In this paper, a less…

  19. Vibrational Stark Effect Probes for Nucleic Acids

    PubMed Central

    Silverman, Lisa N.; Pitzer, Michael E.; Ankomah, Peter O.; Boxer, Steven G.; Fenlon, Edward E.

    2008-01-01

    The vibrational Stark effect (VSE) has proven to be an effective method for the study of electric fields in proteins via the use of infrared probes. In order to explore the use of VSE in nucleic acids, the Stark spectroscopy of nine structurally diverse nucleosides was investigated. These nucleosides contained nitrile or azide probes in positions that correspond to both the major and minor grooves of DNA. The nitrile probes showed better characteristics and exhibited absorption frequencies over a broad range; i.e., from 2253 cm−1 for 2′-O-cyanoethyl ribonucleosides 8 and 9 to 2102 cm−1 for a 13C-labeled 5-thiocyanatomethyl-2’-deoxyuridine 3c. The largest Stark tuning rate observed was |Δµ| = 1.1 cm−1/(MV/cm) for both 5-cyano-2′-deoxyuridine 1 and N2-nitrile-2′-deoxyguanosine 7. The latter is a particularly attractive probe because of its high extinction coefficient (ε = 412 M−1cm−1) and ease of incorporation into oligomers. PMID:17877390

  20. Effects of aerosol formulation to amino acids and fatty acids contents in Haruan extract.

    PubMed

    Febriyenti; Bai-Baie, Saringat Bin; Laila, Lia

    2012-01-01

    Haruan (Channa striatus) extract was formulated to aerosol for wound and burn treatment. Haruan extract is containing amino acids and fatty acids that important for wound healing process. The purpose of this study is to observe the effect of formulation and other excipients in the formula to amino acids and fatty acids content in Haruan extract before and after formulated into aerosol. Precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) method is used for amino acids analysis. Fatty acids in Haruan extract were esterified using transesterification method to form FAMEs before analyzed using GC. Boron trifluoride-methanol reagent is used for transesterification. Tyrosine and methionine concentrations were different after formulated. The concentrations were decrease. There are six fatty acids have amount that significantly different after formulated into concentrate and aerosol. Contents of these fatty acids were increase. Generally, fatty acids which had content increased after formulated were the long-chain fatty acids. This might be happen because of chain extension process. Saponification and decarboxylation would give the chain extended product. Therefore contents of long-chain fatty acids were increase. Generally, the aerosol formulation did not affect the amino acids concentrations in Haruan extract while some long-chain fatty acids concentrations were increase after formulated into concentrate and aerosol.

  1. Effects of acid rain on forest nutrient status

    SciTech Connect

    Johnson, D.W.; Turner, J.; Kelly, J.M.

    1982-06-01

    The paper presents an extensive literature review that deals with the assessment of the effects of acidic atmospheric inputs on forest nutrient status within the context of natural, internal acid production by carbonic and organic acids as well as the nutrient inputs and drains by management practices such as harvesting, fire and fertilization. 123 refs.

  2. Seasonal dynamics in photosynthesis of woody plants at the northern limit of Asian tropics: potential role of fog in maintaining tropical rainforests and agriculture in Southwest China.

    PubMed

    Zhang, Yong-Jiang; Holbrook, N Michele; Cao, Kun-Fang

    2014-10-01

    The lowland tropical rainforests in Xishuangbanna, Southwest (SW) China, mark the northern limit of Asian tropics. Fog has been hypothesized to play a role in maintaining rainforests and tropical crop production in this region, but the physiological mechanism has not been studied. The goals of this study were to characterize the seasonal dynamics in photosynthesis and to assess the potential for fog to mitigate chilling-induced photodamage for tropical trees and crops in Xishuangbanna. We measured seasonal dynamics in light-saturated net photosynthetic rate (Aa), stomatal conductance (gs), intercellular CO2 concentration, quantum yield of Photosystem II (Fv/Fm) and maximum P700 changes (Pm; indicates the amount of active PSI complex), as well as chilling resistance and fog (light/shading) effects on low temperature-induced decline in Fv/Fm and Pm for native tree and introduced lower latitude tree or woody shrub species grown in a tropical botanical garden. Despite significant decreases in Aa, gs, Pm and Fv/Fm, most species maintained considerably high Aa during the cool season (2.51-14.6 μmol m(-2) s(-1)). Shaded leaves exposed to seasonal low temperatures had higher Fv/Fm than sun-exposed leaves in the cool season. All species could tolerate 1.4 °C in the dark, whereas a combined treatment of low temperature and high light caused a distinctly faster decline in Pm and Fv/Fm compared with low temperature treatment alone. Because fog persistence avoids or shortens the duration of high light condition in the morning when the temperatures are still low, our results provide support for the hypothesis that fog reduces chilling damage to tropical plants in this region and thus plays a role in maintaining tropical rainforests and agriculture in SW China.

  3. Hair and amino acids: the interactions and the effects.

    PubMed

    Oshimura, Eiko; Abe, Hiroshi; Oota, Rina

    2007-01-01

    The interaction and the function of some amino acids in hair care applications are discussed. When amino acids are applied to hair in the form of simple aqueous solution, uptake of the amino acids is mainly controlled by ionic equilibrium. When amino acids were incorporated in a hair conditioner, the result was quite different, suggesting the importance of interaction between the amino acids and the cationic surfactants. Uptake of pyrrolidone carboxylic acid (PCA), a derivative of glutamic acid, is enhanced by combining with arginine, an amino with strong affinity towards hair. Effects of some amino acids on bleached/dyed hair are described. A hair conditioner incorporated with alanine improves hair surface hydrophobicity of bleach-damaged hair. Histidine and phenylalanine improve tensile strength. PCA was proved to be effective to improve color-retention of dyed hair.

  4. Hair and amino acids: the interactions and the effects.

    PubMed

    Oshimura, Eiko; Abe, Hiroshi; Oota, Rina

    2007-01-01

    The interaction and the function of some amino acids in hair care applications are discussed. When amino acids are applied to hair in the form of simple aqueous solution, uptake of the amino acids is mainly controlled by ionic equilibrium. When amino acids were incorporated in a hair conditioner, the result was quite different, suggesting the importance of interaction between the amino acids and the cationic surfactants. Uptake of pyrrolidone carboxylic acid (PCA), a derivative of glutamic acid, is enhanced by combining with arginine, an amino with strong affinity towards hair. Effects of some amino acids on bleached/dyed hair are described. A hair conditioner incorporated with alanine improves hair surface hydrophobicity of bleach-damaged hair. Histidine and phenylalanine improve tensile strength. PCA was proved to be effective to improve color-retention of dyed hair. PMID:17728935

  5. Effects of oral eicosapentaenoic acid versus docosahexaenoic acid on human peripheral blood mononuclear cell gene expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have beneficial effects on inflammation and cardiovascular disease (CVD). Our aim was to assess the effect of a six-week supplementation with either olive oil, EPA, or DHA on gene expression in peripheral blood mononuclear cells (...

  6. Enhanced extinction of visible radiation due to hydrated aerosols in mist and fog

    NASA Astrophysics Data System (ADS)

    Elias, T.; Dupont, J.-C.; Hammer, E.; Hoyle, C. R.; Haeffelin, M.; Burnet, F.; Jolivet, D.

    2015-01-01

    The study assesses the contribution of aerosols to the extinction of visible radiation in the mist-fog-mist cycle. Measurements of the microphysical and optical properties of hydrated aerosols with diameters larger than 400 nm, composing the accumulation mode, which are the most efficient to interact with visible radiation, were carried out near Paris, during November 2011, in ambient conditions. Eleven mist-fog-mist cycles were observed, with cumulated fog duration of 95 h, and cumulated mist-fog-mist duration of 240 h. In mist, aerosols grew up by taking up water at relative humidities larger than 93%, causing a visibility decrease below 5 km. While visibility decreased down to few km, the mean size of the hydrated aerosols increased, and their number concentration (Nha) increased from approximately 160 to approximately 600 cm-3. When fog formed, droplets became the strongest contributors to visible radiation extinction, and liquid water content (LWC) increased beyond 7 mg m-3. Hydrated aerosols of the accumulation mode co-existed with droplets, as interstitial non-activated aerosols. Their size continued to increase, and a significant proportion of aerosols achieved diameters larger than 2.5 μm. The mean transition diameter between the accumulation mode and the small droplet mode was 4.0 ± 1.1 μm. Moreover Nha increased on average by 60% after fog formation. Consequently the mean aerosol contribution to extinction in fog was 20 ± 15% for diameter smaller than 2.5 μm and 6 ± 7% beyond. The standard deviation is large because of the large variability of Nha in fog, which could be smaller than in mist or three times larger. The particle extinction coefficient in fog can be computed as the sum of a droplet component and an aerosol component, which can be approximated by 3.5 Nha (Nha in cm-3 and particle extinction coefficient in Mm-1). We observed an influence of the main formation process on Nha, but not on the contribution to fog extinction by aerosols

  7. Regional deposition of inhaled fog droplets: preliminary observations.

    PubMed

    Bowes, S M; Laube, B L; Links, J M; Frank, R

    1989-02-01

    The regional deposition of a monodisperse 10-micron mass median aerodynamic diameter fog was studied in four healthy adult male nonsmokers. The fog was radiolabeled with technetium-99m sulfur colloid to enable detection by an Anger camera of deposited activity in the following regions of the respiratory tract: oropharynx, larynx, trachea, and intrapulmonary airways. Intrapulmonary deposition was further analyzed by computer with inner, intermediate, and outer zones, and within apical, intermediate and basal zones of the right lung. The radiolabeled aerosol was inhaled by mouth through a face-mask with the nasal airway occluded. Respiratory frequency, tidal volume, and jaw position were controlled and were commensurate with the oral component of oronasal breathing during moderate exercise. Deposition in the larynx, trachea, and intrapulmonary airways was a function of the scrubbing efficiency of the oropharynx, which differed substantially among subjects, and ranged from 72 to 99%. The density of the aerosol deposit in the larynx probably exceeded that of any of the subdivisions of the tracheobronchial tree and lung. Within the lung, deposition favored the inner zone (assumed to contain the larger airways) over the outer zone (assumed to be dominated by smaller airways and alveoli). Intrapulmonary aerosol distribution in an elderly subject with borderline evidence of airway obstruction differed from that observed in younger subjects. The possible consequences of altered lung elastic recoil, as may occur with aging, for regional dosimetry is discussed.

  8. Regional deposition of inhaled fog droplets: preliminary observations.

    PubMed Central

    Bowes, S M; Laube, B L; Links, J M; Frank, R

    1989-01-01

    The regional deposition of a monodisperse 10-micron mass median aerodynamic diameter fog was studied in four healthy adult male nonsmokers. The fog was radiolabeled with technetium-99m sulfur colloid to enable detection by an Anger camera of deposited activity in the following regions of the respiratory tract: oropharynx, larynx, trachea, and intrapulmonary airways. Intrapulmonary deposition was further analyzed by computer with inner, intermediate, and outer zones, and within apical, intermediate and basal zones of the right lung. The radiolabeled aerosol was inhaled by mouth through a face-mask with the nasal airway occluded. Respiratory frequency, tidal volume, and jaw position were controlled and were commensurate with the oral component of oronasal breathing during moderate exercise. Deposition in the larynx, trachea, and intrapulmonary airways was a function of the scrubbing efficiency of the oropharynx, which differed substantially among subjects, and ranged from 72 to 99%. The density of the aerosol deposit in the larynx probably exceeded that of any of the subdivisions of the tracheobronchial tree and lung. Within the lung, deposition favored the inner zone (assumed to contain the larger airways) over the outer zone (assumed to be dominated by smaller airways and alveoli). Intrapulmonary aerosol distribution in an elderly subject with borderline evidence of airway obstruction differed from that observed in younger subjects. The possible consequences of altered lung elastic recoil, as may occur with aging, for regional dosimetry is discussed. Images FIGURE 3. A FIGURE 3. B PMID:2539988

  9. Research Spotlight: Lost in a fog on Mars

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2011-04-01

    A pair of cameras mounted on the back of the Phoenix Mars Lander were used to capture how laser light, emitted by the lander's light detection and ranging (lidar) system, was scattered by water ice in the red planet's thin atmosphere. Moores et al. used the unique technique during four nights in 2008 to give the first detailed profile of the ice water content in the Martian near-surface atmosphere. The authors found that the icy fog is thickest around 50 meters above the surface, with a maximum concentration of 1.7 milligrams per cubic meter. They also found that the fog is not uniform but tends to decrease in thickness toward the surface. As the Martian night wears on, the surface of the planet cools below the frost point and water vapor in the atmosphere gets deposited on the ground. As the atmosphere is mixed by turbulence, more water is brought to lower altitudes, adding to the growing frost layer. Ice crystals also form in the air and precipitate to the ground from successively higher altitudes. The researchers estimate that by the time the Sun starts to rise in the morning, 2.5 micrometers of snow and frost have coated the surface of Mars in the northerly region around the Phoenix Lander. (Geophysical Research Letters, doi:10.1029/2010GL046315, 2011)

  10. Regional deposition of inhaled fog droplets: preliminary observations

    SciTech Connect

    Bowes, S.M. III; Laube, B.L.; Links, J.M.; Frank, R.

    1989-02-01

    The regional deposition of a monodisperse 10-micron mass median aerodynamic diameter fog was studied in four healthy adult male nonsmokers. The fog was radiolabeled with technetium-99m sulfur colloid to enable detection by an Anger camera of deposited activity in the following regions of the respiratory tract: oropharynx, larynx, trachea, and intrapulmonary airways. Intrapulmonary deposition was further analyzed by computer with inner, intermediate, and outer zones, and within apical, intermediate and basal zones of the right lung. The radiolabeled aerosol was inhaled by mouth through a face-mask with the nasal airway occluded. Respiratory frequency, tidal volume, and jaw position were controlled and were commensurate with the oral component of oronasal breathing during moderate exercise. Deposition in the larynx, trachea, and intrapulmonary airways was a function of the scrubbing efficiency of the oropharynx, which differed substantially among subjects, and ranged from 72 to 99%. The density of the aerosol deposit in the larynx probably exceeded that of any of the subdivisions of the tracheobronchial tree and lung. Within the lung, deposition favored the