Dew

Cations (pH, potassium, sodium, calcium, magnesium, and ammonium) and anions (sulfate, nitrate, nitrite, and chloride) concentrations were measured in Santiago city rain and dew waters collected during the 1995 to 1999. Concentrations measured in dews are considerably higher than those measured in rains. The high ionic concentration present in dew waters could contribute to their corrosion potential. Natural dust makes an important contribution to the ions present in dews, but the presence of rather high sulfate concentrations (up to 900 meq/l) indicate a significant contribution of anthropogenic sources.

Although the Namib Desert is classified as hyperarid, with rainfall extremely rare, there are several other sources of atmospheric moisture, namely, humidity, dew and fog, which make it possible for organisms to live there. Methods to use these sources include locating moist micro-climates, drinking from wet surfaces, consuming moist food, collecting water on the body, and absorbing water vapour. In describing these mechanisms from published sources, we highlight the work of Professor Gideon Louw, to whom we dedicate this paper. Louw's pioneering work on water relations and economy, which includes osmoregulation in desert plants and animals such as grass, beetles, and springbok, established a foundation that inspired numerous studies by colleagues and students. Ecophysiology provides many more lessons that have potential to be mimicked and applied in the occult collection of water in arid regions.

Twenty-six dew samples were collected on a glass surface from an urbanized area in Amman Ž city during the period October 1999 to June 2000. They were analyzed for the major ions Cl, . Ž . SO , NO , Ca, Mg, Na, K and NH in addition to three heavy metals Pb, Cd and Co . Rain 4 3 4 samples were collected for the same period and compared to the chemical constituents of dew. It was found that both rain and dew samples were of almost neutral acidity due to the buffering effect of CaCO . Dew composition was mainly from CaSO solution due to conversion of CaCO 3 4 3

ABSTRACT Summary • The effects of free radicals, ·OH and ·NO, generated in polluted dew water on needles of Pinus densiflora (Japanese Red pine) were investigated. • ·OH-generating solutions (HOOH with Fe(III) and oxalate ion; ·OH treatment) and ·OH- and ·NO-generating solutions (NO2−; ·OH/·NO treatment) were regulated at 25, 50 and 100 µmol and pH 4.4. HOOH only (HOOH treatment) was used as a control solution. Solutions were applied as a mist to the needle surface of P. densiflora seedlings before dawn twice a week for 3 months. • Within a month, net photosynthesis at near saturating irradiance (Pn) and stomatal conductance (gl) of ·OH-treated needles decreased with increasing solution concentration. The HOOH treatment had no effects on any of the measured parameters. Therefore, ·OH in the artificial dews caused the decreases in Pn and gl. In ·OH/·NO-treated needles, gl increased during the experiment, but Pn was unchanged. In all experiments, the characteristics of PSII were not significantly altered. • Free radicals in polluted dew water have harmful effects on the photosynthesis of P. densiflora and compound effects of ·OH and ·NO are different.

Although lichens are important components of arid ecosystems, the influence of microclimatic factors (particularly dew) conducive to their distribution on rock habitats in the Negev Desert are still not sufficiently investigated. Here, we present a study on adjacent lichen communities inhabiting slightly acidic flint (chert) and slightly alkaline limestone cobbles in the north-facing slopes of two sites in the Negev Desert, Nizzana, NIZ (with long-term mean precipitation of 95 mm and average daily dew amount of 0.1 mm) and Sede Boqer, SB (with long-term mean precipitation of 95 mm and average daily dew amount of 0.2 mm). The communities on flint consisted of either scarce or lush cover of exclusively epilithic species, while endolithic lichens predominated on limestone. Following previous measurements that indicated that similar dew amounts characterize limestone and flint cobbles, we hypothesized that differences in the flint-and limestone-lichen communities may stem from differences in dew duration. Our results pointed indeed to the fact that while non-significant differences characterized the amounts of dew condensed on both substrates, dew duration on some of the flint cobbles (such as flat cobbles that readily permits long-lasting condensation) was by ∼1.2 longer. With longer dew duration, the cover of the epilithic lichens Aspicilia contorta subsp. hoffmanniana and Buellia sorediosa on flint increased along with the cover of the fruticose lichen Ramalina maciformis. Some of the species (Caloplaca circumalbata var. circumalbata, Caloplaca flavocitrina, Caloplaca oasis, Candelariella minuta, Diplotomma epipolium) inhabited both substrates pointing to the possibility that dew duration rather than alkalinity determines their distribution. While not explaining the higher lichen cover on limestone, dew duration explains the significantly higher cover of epilithic lichens and chlorophyll content (per inhabited surface) on flint in comparison to limestone.

Dew water samples were collected during the winter season (December, 2014 to January, 2015) at an outflow location from the Indo-Gangetic Plain (IGP) to the Bay of Bengal (Coastal Bhola, Bangladesh). Physical properties of the dew water, including pH and electrical conductivity (EC), were measured. The concentrations of water soluble ions (Cl − , SO 4 2− , NO 3 − , HCO 3 − , Na + , K + , Ca 2+ , and Mg 2+) and trace metals (Zn, Fe, Mn, Cu, Cr, Pd, and Ni) were also measured. Source characterization of the chemical species was done by correlation analysis, enrichment factor analysis, percent source contribution calculation, and air mass trajecto-ry analysis. The average pH and

Biomaterials from olive tree pruning are an abundant agricultural residue in various Mediterranean regions. A suggested use of this residue is its separation in a main fraction (trunks and stems with diameter > 1 cm) and a residual fraction (leaves and stems with diameter 1 < cm), using biorefinery procedures. The main fraction is cooked with ethanol, giving rise to a pulp, which can be used either in paper or in bioethanol production if before pulping the main fraction is subjected to a hydrothermal treatment. Pulping with 70% ethanol concentration, 185 °C for 80 min resulted in a pulp with a yield of 46.30% and a content of holocellulose, α-cellulose, and lignin of 77.17%, 62.49%, and 21.73%, respectively. The paper sheets obtained had a breaking length of 1168 m, a burst index of 0.44 kN /g, a tear index of 2.25 mN.m 2 /g, and a brightness of 43.66%. The pulp converted into bioethanol (by simultaneous hydrolysis and fermentation) achieved a conversion of 70 g bioethanol/100 g potential bioethanol. The residual fraction of olive tree prunings was subjected to combustion to produce thermal energy. The heating value was 18700 kJ/kg, the flame temperature range was 1094 to 2013 ºC, and the dew point temperature range of the flue gases was 47 to 53 °C.

Leaf wetness duration (LWD) estimation models developed in the midwestern U.S. were assessed for portability to northwestern Costa Rica during wet and dry seasons. The CART/SLD/Wind (CART) model overestimated LWD by 5.4 h at five sites in northwestern Costa Rica during the 1999 wet season. The Fuzzy (FL) model, in contrast, estimated LWD at the same sites within 3 h. During the 2000-2001 and 2002-2003 dry seasons, both models underestimated LWD at most sites, probably due to the prevalence of less humid conditions than in the temperate climate of the midwestern U.S. However, accuracy of the FL model was substantially improved when a correction factor was utilized during the 2002-2003 dry season, indicating that this model could be adjusted to estimate LWD in a semi-arid climate with acceptable accuracy. The results suggested that the adjusted FL model could estimate LWD accurately in other tropical regions with climate regimes similar to northwestern Costa Rica.

Knowledge regarding dew and fog precipitation in relation to angle and aspect may be of great importance to plant photosynthesis and to rock dwelling microorganisms, especially in arid land where water is highly limited. Measurements of dew and fog were carried out periodically during the fall of two years (1989, 1992) at a hilltop in the Negev Desert Highlands, Israel. Measurements were carried out using velvet-like cloths (6!6!0.15 cm) attached to the center of different angle sides of 5 pairs of wooden boxes (50!50!10 cm) and to the top of an additional pair (10!10!5 cm) that served as a control (horizontal surface). The sides of each pair of boxes had angles of 30, 45, 60, 75 and 908 facing north, east, south and west.

Concentrations of several major rainwater components were determined in rain events occurring during the early morning hours (12:00 midnight to 6:00 am) and during the afternoon (12:00 noon to 6:00 pm) to examine possible diurnal variations. Generally, rainwater components with ...

Water availability is the most important limiting factor in arid lands. Any additional source of water, such as dew and fog, may have a positive impact upon the ecosystem. Dew and fog precipitation are largely dictated by weather conditions and habitat.Dew and fog measurements were carried out for 29 days in the fall of 1987–1989 at three distinctive habitats within

This study reconsidered the cause of forest decline of Japanese red pine (Pinus densiflora Sieb. et Zucc.) in the Seto Inland Sea area, western Japan. Although the decline in pine forests was attributed to pine-wood nematode infection, the stress of air pollution was also shown to have negative physiological effects on pine needles. Secondary pollutants related to NOx accumulate in the morning dew then liquid-phase free radicals (•OH) form by photochemical reactions on the needle surface. The stress of polluted dew induces faster needle senescence and defective needle gas exchange. The influence of atmospheric O3 and SO2 was not significant. Understory vegetation also had negative physiological effects on the overstory pine needles through competition of roots for water and nutrients. Abandonment of management accelerates growth of understory vegetation causing decline of P. densiflora plantations. Each of these stresses was shown to independently and significantly reduce needle pho...

Dew is a phenomenon that is experienced daily. It is formed of water droplets that imperfectly wet the substrate on which they condense. The formation of dew is connected to rich and numerous physical phenomena: heterogeneous nucleation, phase transitions, heat transfer, wetting. Although the growth of an isolated droplet still remains imperfectly understood, growth of an assembly of drops is

Airborne high-speed synchronous generators rated in the power range of megawatts have been discussed. These generators are nowadays necessary for new aerospace missions, such as directed energy weapon (DEW) and airborne radar (AR). Requirements, ferromagnetic materials for magnetic circuits, electromagnetic design and cooling techniques for highspeed multimegawatt generators have been discussed. New sizing procedure has been proposed. First prototypes (1 MW and 2.5 MW) have been outlined.

An optical wetness sensor (OWS) was developed for continuous surface wetness measurements. The sensor is an all-weather instrument that does not interfere with the surface wetting and drying process and is unaffected by solar radiation. It is equipped with its own light source with which it can scan a surface and analyse its spectral reflectance. The backscattered radiation is detected around two wave bands: 1.70 mm (170 nm waveband) and 1.94 mm (80 nm waveband). The optical design is such that the ratio of the two signals is not dependent on the sampling distance, hence making it possible to study leaves under field conditions. Field and lab testing showed that the OWS was also capable of resolving small changes in surface soil water content such as from dew. In addition, the change of leaf water content could be detected (accuracy 5%). The OWS was also capable of measuring small changes in water content in the upper soil layer (<2 mm) of a loamy and fine sandy soil. For plant leaves it must be noted that the OWS responds to both internal and external water and thus cannot always discern between them.

Kogan & Trahtman (2003) analyzed the functioning of a passive dew condenser built by F.I. Zibold in 1912 in Feodosia, and proposed a model to explain how thousands of litres of condensed water might be generated per day based on Zibold"s design. In a previous publication, some of the present co-authors explained why it was not possible to obtain high water yields with Zibold-style dew condensers and that Zibold was apparently unaware that the stone heaps in Feodosia were in fact ancient Scythian and Greek tombs. Kogan & Trahtman (2003) take issue with our findings, thus the reason for this comment.

Wetness is a key factor in the development of various foliar pathogens on turfgrass. A spectroradiometric approach was used to measure dew and precipitation in short turfgrass (creeping bentgrass and bluegrass) canopies, because of the unavailability of sensors representing the leaf size and the need not to disturb such a short canopy environment. Measurements of reflectance, between 400 and 2250 nm with a field portable spectroradiometer, showed that the erectophile rough bluegrass (about 4 cm height) trapped more radiation within the canopy, hence lowering the reflectance, than the planophile homogeneous bentgrass (about 1 cm height). For both dew and rain-covered bentgrass canopies, reflectance increased in the visible (VIS), about 50 and 16%, respectively, and decreased in the middle-infrared (MIR), about 45 and 28%, respectively. However, changes in dew reflectance on the bluegrass canopy were mainly observed in the near-infrared (NIR) and MIR (9 and 19% decrease, respectively), as the reflectance in the VIS was almost unaffected (about 4% increase). The light precipitation affected the bluegrass reflectance by mainly decreasing NIR (765-960 nm) wavelengths. Relationships were generally weak for the dew-covered bluegrass reflectance, but a strong quadratic relationship at 1165 nm reflectance was found under rainy conditions. Strong quadratic relationships were found between dew-covered bentgrass and MIR/green and MIR/red ratios. The reflectance at 1165 nm (r 2 = 0.95) showed the greatest response to increasing wetness either for dew or rainfall, suggesting that the reflectance at this wavelength may be used on a remote sensor to measure wetness on bentgrass canopies.

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Peroxides present in Santiago City dew waters readily decompose with first order kinetics. In order to minimize the loss of peroxides during the time elapsed between deposition and collection, the collectors were pre-treated with a mercury chloride solution. This reduces, but not completely eliminates, the decomposition. A correction is introduced by a comparison of the levels and decomposition kinetics of the samples collected in treated and untreated collectors. The average concentration estimated by this procedure was 8.1 mM. The mechanism of peroxide decomposition and its stabilization is discussed. ᮊ

Dew was collected in Santiago City at different locations and over different surfaces. High pHs (ca 7.0) and nitrite concentrations were observed in all the samples, irrespective of the location of the sampler and the material of the collecting surface. pH of the samples correlates with sulfate, nitrate and ammonium concentrations. This parameter is the most important determinant of the amount of nitrite present in the collected dew. This suggests that transfer from the gas phase could be relevant in HONO capture. The increase in nitrite concentrations in dew collected during the period from 1995 to 2006 can be explained in terms of an increase in the average samples' pH along this period.

Series of tethered balloon soundings of temperature and humidity in Austria’s Gruenloch basin (floor elevation 1270 m MSL) on two June days showed that the water vapor mixing ratio fell by 2–3 g kg−1 overnight as dew or frost formed in the basin. After sunrise, the basin atmosphere remoistened as higher humidity was brought down into the basin from above and as evapotranspiration occurred from the basin floor and sidewalls. The latent heat released at night by the dewfall/frostfall was 33%–53% of the overall observed basin sensible heat loss, illustrating the important role of dew and frost formation on the nighttime heat budget of the basin atmosphere. An energy budget equation illustrates the decreasing importance of the latent heat release on the overall basin heat budget as ambient temperatures fall from summer to winter. Because the diurnal temperature range is frequently larger than the late-afternoon dewpoint depression, fog and clouds often form in this basin. The extreme te...

Physicochemical (i.e., sulfhydryl group, protein, and total solubility) as well as functional properties (i.e., water-holding and fat-absorption capacity, foaming and emulsification capacity, and stability) of commercial buttermilk solids (BMS) were compared to nonfat dried milk, soy protein isolate, and dried egg yolk and egg white powders on an equivalent protein basis. BMS showed limited functional properties in water-holding capacity (0.75 g water/g protein) and fat-absorption capacity (1.2 g of oil/g of protein), and foaming capacity (0.5 ml of foam/ml of solution) and stability. However, emulsifying capacity and stability of BMS was not significantly different from other dried protein powders. Results indicated that 0.9 g of protein (approximately 0.45%, wt/vol, concentration) from BMS was needed to emulsify a maximum oil concentration of 50% in water at temperatures up to 50 degrees C. Denaturation of protein, quantified by free sulfhydryl groups, was a critical factor affect...

Samples of White and Green Carrara marble, and three types of limestone and brick exposed in the field vertically and horizontally were used to evaluate condensation on monuments during clear sky nights. Experiments in a simulation chamber under controlled conditions led to a general equation for the actual amount of water deposited on a surface by dew. This is determined by: How much and for how long the surface temperature falls below the dew point, the moisture content in the air and the ventilation. On clear nights, the condensation on building structures facing the sky may reach some 0.2 kg m −2 (or 0.2 mm), whereas condensation on vertical surfaces is very small. Computation of the seasonal trend of night-time condensation showed that the maximum amount of water condensed per night occurs in the autumn, with the more abundant concentration of moisture in the air. The total amount of water condensed per month is found to be a maximum in the summerautumn period. Morning condensation for the thermal inertia of monuments is also relevant, and has been calculated to reach the same order of magnitude as the nocturnal dew. A detailed analysis of the temperature and mixing ratio profiles near a condensing surface has shown two different situations. In still air, the two profiles follow an exponential law and the thermal and the concentration layers lie within a few tens of millimetres. In the presence of turbulence, the thickness of these two layers is dramatically reduced. In still air, in front of a vertical, chilly surface, the deposition rate of air pollutants by thermophoresis and/or Stefan flow is increased by 3 or 4 times in comparison with a horizontal surface. In the presence of turbulence, the thickness of the thermal and concentration layers was dramatically reduced, making these two kinds of deposition much faster.

Dew is the condensation into liquid droplets of water vapor on a substrate. The presence of a substrate is the origin of the peculiarities and richness of the phenomenon. We review the aspects related to heterogeneous nucleation and subsequent growth of water droplets. A key point is the drop interaction through drop fusion or coalescence, which leads to scaling in the growth and gives universality to the process. The effects of substrate heterogeneity and gravity effects are also considered. Coalescence events lead to temporal and spatio-temporal fluctuations in the substrate coverage, drop configuration, etc., which give rise to a very peculiar dynamics. When the substrate is a liquid or a liquid crystal, the drop pattern can exhibit special spatial orders, such as crystalline, hexatic phases and fractal contours. And condensation on a solid substrate near its melting point can make the drop jump. The applications of monitoring dew formation are manyfold. Examples can be found in nanoelectronics and optics (vapor deposition and thin films), medicine (sterilization process), agriculture (green houses). We here discuss in greater details the production of clean water by "atmospheric wells".

Nitrite was measured in atmospheric liquid phase samples between 1998 and 2005 to investigate the heterogeneous formation of nitrous acid in the lower atmosphere, as well as to assess the quality of water recovered from dew. The samples were collected during ground-based cloud field experiments at different German mountain sites (Brocken, Schmücke, and Hohenpeissenberg) and at a site south of the Bordeaux urban area (France). Concentrations found in Bordeaux dew samples (up to 2800 μg l − 1) are comparable to those found elsewhere in urban fog and dew water and considerably higher than those detected in cloud water or rain. Particulate nitrite (and nitrate) as well as HNO 2 (HNO 3) data in air masses from a foothill site of Mt. Schmücke, before involved in cloud processing, are also presented. In clouds at Mt. Brocken, both the interstitial HNO 2 gas and the aqueous phase nitrite concentration have been measured simultaneous. Significant deviations from Henry's law have been observed, indicating that a calculation of HNO 2 from measured solute nitrite concentrations in bulk samples will overestimate the gasphase concentration. Besides the heterogeneous HNO 2 production on wetted surfaces with contact to atmospheric air, a fraction of nitrite measured in cloud droplets or dew will arise from the dissolution of gasphase HNO 2 , the particle scavenging processes or the dissolution of surface substrates. HNO 2 is a dominant hydroxyl radical source during daytime due to its effective photolysis and after water evaporation the released nitrite can significantly contribute to the total OH production and therefore to photochemical smog conditions in the lower atmosphere.

Bibliography Adams, Percy G. Travel Literature and the Evolution of the Novel. Lexington: University Press of Kentucky, 1983. Agnew, John. Geopolitics: Re-visioning World Politics. London and New York: Routledge, 1998. Anderegg, Michael, ed. Inventing Vietnam: The War in Film ...

During summer and autumn 2007, a 11 GHz microwave radiometer was deployed in an experimental tree plantation in Sardinilla, Panama. The opacity of the tree canopy was derived from incoming brightness temperatures received on the ground. A collocated eddy-covariance flux tower measured water vapor fluxes and meteorological variables above the canopy. In addition, xylem sapflow of trees was measured within the flux tower footprint. We observed considerable diurnal differences between measured canopy opacities and modeled theoretical opacities that were closely linked to xylem sapflow. It is speculated that dielectric changes in the leaves induced by the sapflow are causing the observed diurnal changes. In addition, canopy intercepted rain and dew formation also modulated the diurnal opacity cycle. With an enhanced canopy opacity model accounting for water deposited on the leaves, we quantified the influence of canopy stored water (i.e. intercepted water and dew) on the opacity. A time series of dew formation and rain interception was directly monitored during a period of two weeks. We found that during light rainfall up to 60% of the rain amount is intercepted by the canopy whereas during periods of intense rainfall only 4% were intercepted. On average, 0.17 mm of dew was formed during the night. Dew evaporation contributed 5% to the total water vapor flux measured above the canopy.

Dew and rainwater samples were collected during winter and monsoon periods in 1997-1998 at Rampur, India, a semiarid site with minimal anthropogenic activities. The study revealed that the decreasing order of ionic concentration in dew is Ca 2+ N SO 4 2À À , SO 4 2À , HCOO À and CH 3 COO À from soil or they are associated with Ca 2+ , Mg 2+ and K + after neutralization. At the present site, in dew, NH 4 + is 6 times, Ca 2+ and Mg 2+ more than 7 times, K + and Na + greater than 10 times and Cl À , NO 3 À , and SO 4 2À are more than 9 times higher than those of rainwater. The steps governing dew composition are: (i) formation on dry deposition solids, (ii) dissolution of the soluble portion of the dry deposition by dew water, and (iii) sorption of gaseous NH 3 , formate and acetate into dew water. D

a g r i c u l t u r a l a n d f o r e s t m e t e o r o l o g y 1 4 8 ( 2 0 0 8 ) 3 9 2 -4 0 0 Temperature Empirical models Epidemiological models a b s t r a c t Leaf wetness duration (LWD) is a key parameter in agricultural meteorology since it is related to epidemiology of many important crops, controlling pathogen infection and development rates. Because LWD is not widely measured, several methods have been developed to estimate it from weather data. Among the models used to estimate LWD, those that use physical principles of dew formation and dew and/or rain evaporation have shown good portability and sufficiently accurate results, but their complexity is a disadvantage for operational use.