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F N Scatena - One of the best experts on this subject based on the ideXlab platform.
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comparison of passive Fog gauges for determining Fog duration and Fog interception by a puerto rican elfin cloud forest
Hydrological Processes, 2011Co-Authors: F Holwerda, L A Bruijnzeel, F N ScatenaAbstract:Between 5 March and 10 May 2001, the performance of three types of passive Fog gauges (wire harp WH, standard Fog collector SC and Juvik gauge JU) was compared at a wind-exposed Puerto Rican elfin cloud forest site. The gauges were used to determine the timing and duration of Fog, as well as Fog-induced crown drip using gauge to canopy conversions factors. The latter were calculated as the average ratio between throughfall, and Fog collected by the respective gauges during periods with Fog-only and negligible evaporation loss. The Fog gauges indicated very similar timing and Fog duration, presumably because dense Fog prevailed for 75–80% of the time whereas winds were generally sufficiently strong (4–5 m s−1) and from a nearly constant direction. Resulting gauge to canopy factors were 0·12 for WH and SC, and 0·10 for JU. Estimating Fog interception by the elfin forest canopy using these conversion factors gave very similar values for the three gauge types (mean rates of 0·15 ± 0·01 mm h−1). Throughfall typically started about 5 h after the Fog gauges indicated the beginning of a Fog event. This time lag probably reflects the filling of the canopy storage capacity. Integrating the estimated Fog interception rates over the time lag suggested an average value of 0·4 mm for the canopy storage capacity during Fog-only events. The present results are expected to apply to sites with comparable wind and Fog conditions. Copyright © 2010 John Wiley & Sons, Ltd.
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Comparison of passive Fog gauges for determining Fog duration and Fog interception by a Puerto Rican elfin cloud forest
Hydrological Processes, 2010Co-Authors: F Holwerda, L A Bruijnzeel, F N ScatenaAbstract:Between 5 March and 10 May 2001, the performance of three types of passive Fog gauges (wire harp WH, standard Fog collector SC and Juvik gauge JU) was compared at a wind-exposed Puerto Rican elfin cloud forest site. The gauges were used to determine the timing and duration of Fog, as well as Fog-induced crown drip using gauge to canopy conversions factors. The latter were calculated as the average ratio between throughfall, and Fog collected by the respective gauges during periods with Fog-only and negligible evaporation loss. The Fog gauges indicated very similar timing and Fog duration, presumably because dense Fog prevailed for 75–80% of the time whereas winds were generally sufficiently strong (4–5 m s−1) and from a nearly constant direction. Resulting gauge to canopy factors were 0·12 for WH and SC, and 0·10 for JU. Estimating Fog interception by the elfin forest canopy using these conversion factors gave very similar values for the three gauge types (mean rates of 0·15 ± 0·01 mm h−1). Throughfall typically started about 5 h after the Fog gauges indicated the beginning of a Fog event. This time lag probably reflects the filling of the canopy storage capacity. Integrating the estimated Fog interception rates over the time lag suggested an average value of 0·4 mm for the canopy storage capacity during Fog-only events. The present results are expected to apply to sites with comparable wind and Fog conditions. Copyright © 2010 John Wiley & Sons, Ltd.
J.a. Moreto - One of the best experts on this subject based on the ideXlab platform.
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Effect of Localized Corrosion on Fatigue–Crack Growth in 2524-T3 and 2198-T851 Aluminum Alloys Used as Aircraft Materials
Journal of Materials Engineering and Performance, 2018Co-Authors: J.a. Moreto, J. C.s. Fernandes, Luciana Sgarbi Rossino, Evandro Eduardo Broday, W. W. Bose-filhoAbstract:Corrosion and fatigue of aluminum alloys are major issues for the in-service life assessment of aircraft structures and for the management of aging air fleets. The aim of this work was to evaluate the effect of localized corrosion on fatigue crack growth (FCG) resistance of the AA2198-T851 Al-Li alloy (Solution Heat Treated, Cold Worked, and Artificially Aged), comparing it with the FCG resistance of AA2524-T3 (Solution Heat Treated and Cold Worked), considering the effect of seawater Fog environment. Before fatigue tests, the corrosion behavior of 2198-T851 and 2524-T3 aluminum alloys was verified using open circuit potential and potentiodynamic polarization techniques. Fatigue in air and corrosion fatigue tests were performed applying a stress ratio (R) of 0.1, 15 Hz (air) and 0.1 Hz (seawater Fog) frequencies, using a sinusoidal waveform in all cases. The results showed that the localized characteristics of the 2198-T851 and 2524-T3 aluminum alloys are essentially related to the existence of intermetallic compounds, which, due to their different nature, may be cathodic or anodic in relation to the aluminum matrix. The corrosive medium has affected the FCG rate of both aluminum alloys, in a quite similar way.Graphical Abstract
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effect of localized corrosion on fatigue crack growth in 2524 t3 and 2198 t851 aluminum alloys used as aircraft materials
Journal of Materials Engineering and Performance, 2018Co-Authors: J.a. Moreto, J. C.s. Fernandes, Luciana Sgarbi Rossino, Evandro Eduardo Broday, W Bose W FilhoAbstract:Corrosion and fatigue of aluminum alloys are major issues for the in-service life assessment of aircraft structures and for the management of aging air fleets. The aim of this work was to evaluate the effect of localized corrosion on fatigue crack growth (FCG) resistance of the AA2198-T851 Al-Li alloy (Solution Heat Treated, Cold Worked, and Artificially Aged), comparing it with the FCG resistance of AA2524-T3 (Solution Heat Treated and Cold Worked), considering the effect of seawater Fog environment. Before fatigue tests, the corrosion behavior of 2198-T851 and 2524-T3 aluminum alloys was verified using open circuit potential and potentiodynamic polarization techniques. Fatigue in air and corrosion fatigue tests were performed applying a stress ratio (R) of 0.1, 15 Hz (air) and 0.1 Hz (seawater Fog) frequencies, using a sinusoidal waveform in all cases. The results showed that the localized characteristics of the 2198-T851 and 2524-T3 aluminum alloys are essentially related to the existence of intermetallic compounds, which, due to their different nature, may be cathodic or anodic in relation to the aluminum matrix. The corrosive medium has affected the FCG rate of both aluminum alloys, in a quite similar way.
Jonathan S. Price - One of the best experts on this subject based on the ideXlab platform.
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sources and sinks of sea salt in a newfoundland blanket bog
Hydrological Processes, 1994Co-Authors: Jonathan S. PriceAbstract:Over an oceanic peatland, the concentration of Na in Fog averaged 38.1 mgl−1 compared with 1.8 mgl−1 in rain, resulting in a significant flux of mineral elements to the surface. Between 16 May and 20 June 1990 the average mass flux of Na to the bog surface by Fog, rain, and dry deposition was 21.9, 10.4 and 7.0 mg m−2 d−1. There was little long-term storage of Na within the peatland system, where Na losses measured in stream runoff averaged 34.8 mg m2 d−1, and deep groundwater losses 4 mg m−2 d−1. Calcium and Mg were preferentially retained in the organic soil, whereas K was relatively mobile. Potassium tended to become concentrated in the unsaturated zone. Stream runoff had a consistently higher pH than groundwater, corresponding to higher Ca and Mg concentrations, which may have been from mineral sources in the headwater ponds. Otherwise, the stream water chemistry was closely related to groundwater in the upper layers of the peat deposit.
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Blanket bog in Newfoundland. Part 2. Hydrological processes
Journal of Hydrology, 1992Co-Authors: Jonathan S. PriceAbstract:Abstract The water balance was calculated for a 9.4 ha blanket bog basin between 5 and 28 July 1989, and between 16 May and 24 June 1990. Rainfall for these periods was 174 mm and 231 mm, respectively, and Fog deposition added 31 mm and 23 mm of water to the inputs, respectively. Runoff was the largest loss, accounting for 70% and 63% of inputs in 1989 and 1990, respectively, compared with 24% and 28% for evaporation, and 6% for groundwater seepage. Fog simultaneously enhances the inputs and reduces the evaporative loss. Evaporation occurs at the potential rate for a very short period following Fog, but decreases quickly as the surface dries, making it difficult to predict. Pipe-flow and high near-stream gradients, coupled with the high transmissivity of the elevated water table, produce a flashy hydrograph. The maritime climate maintains a high water table, despite relatively steep gradients, which is essential to the development of blanket bog systems in Newfoundland.
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blanket bog in newfoundland part 1 the occurrence and accumulation of Fog water deposits
Journal of Hydrology, 1992Co-Authors: Jonathan S. PriceAbstract:Fog deposition on to a blanket bog near Cape Race, Newfoundland, was measured with a Fog collector and a lysimeter. Fog is most frequently produced by warm southwesterly air flow over cold offshore water, although cooler northeasterly air is also important. Between 21 June and 14 July 1989 Fog deposition was 50% of rainfall, averaging 1.8 mm day−1, with a maximum daily deposition of 10.2 mm. Evaporation was also restricted during Fog and rain events; evaporation on days with Fog or rain averaged <1.1 mm, compared with 2.5 mm when it was not Foggy or raining. The addition of water to the surface by Fog, combined with low evaporation rates may be critical to the development of blanket bog in this area.
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Blanket bog in Newfoundland. Part 1. The occurrence and accumulation of Fog-water deposits
Journal of Hydrology, 1992Co-Authors: Jonathan S. PriceAbstract:Fog deposition on to a blanket bog near Cape Race, Newfoundland, was measured with a Fog collector and a lysimeter. Fog is most frequently produced by warm southwesterly air flow over cold offshore water, although cooler northeasterly air is also important. Between 21 June and 14 July 1989 Fog deposition was 50% of rainfall, averaging 1.8 mm day−1, with a maximum daily deposition of 10.2 mm. Evaporation was also restricted during Fog and rain events; evaporation on days with Fog or rain averaged
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Evaporation from a blanket bog in a Foggy coastal environment
Boundary-Layer Meteorology, 1991Co-Authors: Jonathan S. PriceAbstract:Frequent Fog severely restricts evaporation from blanket bogs in Newfoundland because it more than halves the radiant energy input, and it eliminates the vapor pressure deficit, resulting in evaporation at the equilibrium rate (average α = 0.99 during Fog). During these periods, there is no surface resistance to evaporation because the bog has been wetted by Fog drip, and although the latent heat flux dominates over sensible heat (average β = 0.8), both are small. In contrast, the surface dries during clear periods, increasing the surface resistance to evaporation so that sensible heat becomes more important (β = 1.05). When the mosses are dry, evaporation is below the equilibrium rate (α = 0.87), although the higher available energy ensures that actual evaporation is higher. During clear periods, daily evaporation averaged 2.5 mm, compared to 1.1 and 0.7 mm for Fog and rain, respectively. The suppressed evaporation at this site is important in maintaining appropriate hydrological conditions for blanket bog development.
Gerd A Blobel - One of the best experts on this subject based on the ideXlab platform.
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Fog 1 recruits the nurd repressor complex to mediate transcriptional repression by gata 1
The EMBO Journal, 2005Co-Authors: Wei Hong, Minako Nakazawa, Yingyu Chen, Rajashree Kori, Christopher R Vakoc, Carrie Rakowski, Gerd A BlobelAbstract:Transcription factor GATA-1 and its cofactor Fog-1 coordinate erythroid cell maturation by activating erythroid-specific genes and repressing genes associated with the undifferentiated state. Here we show that Fog-1 binds to the NuRD corepressor complex in vitro and in vivo. The interaction is mediated by a small conserved domain at the extreme N-terminus of Fog-1 that is necessary and sufficient for NuRD binding. This domain defines a novel repression module found in diverse transcriptional repressors. NuRD is present at GATA-1/Fog-1-repressed genes in erythroid cells in vivo. Point mutations near the N-terminus of Fog-1 that abrogate NuRD binding block gene repression by Fog-1. Finally, the ability of GATA-1 to repress transcription was impaired in erythroid cells expressing mutant forms of Fog-1 that are defective for NuRD binding. Together, these studies show that Fog-1 and likely other Fog-like proteins are corepressors that link GATA factors to histone deacetylation and nucleosome remodeling.
W Bose W Filho - One of the best experts on this subject based on the ideXlab platform.
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effect of localized corrosion on fatigue crack growth in 2524 t3 and 2198 t851 aluminum alloys used as aircraft materials
Journal of Materials Engineering and Performance, 2018Co-Authors: J.a. Moreto, J. C.s. Fernandes, Luciana Sgarbi Rossino, Evandro Eduardo Broday, W Bose W FilhoAbstract:Corrosion and fatigue of aluminum alloys are major issues for the in-service life assessment of aircraft structures and for the management of aging air fleets. The aim of this work was to evaluate the effect of localized corrosion on fatigue crack growth (FCG) resistance of the AA2198-T851 Al-Li alloy (Solution Heat Treated, Cold Worked, and Artificially Aged), comparing it with the FCG resistance of AA2524-T3 (Solution Heat Treated and Cold Worked), considering the effect of seawater Fog environment. Before fatigue tests, the corrosion behavior of 2198-T851 and 2524-T3 aluminum alloys was verified using open circuit potential and potentiodynamic polarization techniques. Fatigue in air and corrosion fatigue tests were performed applying a stress ratio (R) of 0.1, 15 Hz (air) and 0.1 Hz (seawater Fog) frequencies, using a sinusoidal waveform in all cases. The results showed that the localized characteristics of the 2198-T851 and 2524-T3 aluminum alloys are essentially related to the existence of intermetallic compounds, which, due to their different nature, may be cathodic or anodic in relation to the aluminum matrix. The corrosive medium has affected the FCG rate of both aluminum alloys, in a quite similar way.