Field-scale water transport in unsaturated crystalline rock

Safe disposal of toxic wastes in geologic formations requires minimal water and gas movement in the vicinity of storage areas, Ventilation of repository tunnels or caverns built in solid rock can desaturate the near field up to a distance of meters from the rock surface, even when the surrounding geological formation is saturated and under hydrostatic pressures. A tunnel segment at the Grimsel test site located in the Aare granite of the Bernese Alps (central Switzerland) has been subjected to a resaturation and, subsequently, to a controlled desaturation, Using thermocouple psychrometers (TP) and time domain reflectometry (TDR), the water potentials psi and water contents theta were measured within the unsaturated granodiorite matrix near the tunnel wall at depths between 0 and 160 cm. During the resaturation the water potentials in the first 30 cm from the rock surface changed within weeks from values of less than -1.5 MPa to near saturation. They returned to the negative initial values during desaturation, The dynamics of this saturation-desaturation regime could be monitored very sensitively using the thermocouple psychrometers, The TDR measurements indicated that water contents changed dose to the surface, but at deeper installation depths the observed changes were within the experimental noise. The field-measured data of the desaturation cycle were used to test the predictive capabilities of the hydraulic parameter functions that were derived from the water retention characteristics psi(theta) determined in the laboratory. A depth-invariant saturated hydraulic conductivity k(s) = 3.0 x 10(-11) m s(-1) was estimated from the psi(t) data at all measurement depths, using the one-dimensional, unsaturated water flow and transport model HYDRUS Vogel er al., 1996, For individual measurement depths, the estimated k(s) varied between 9.8 x 10(-12) and 6.1 x 10(-11) The fitted k(s) values fell within the range of previously estimated k(s) for this location and led to a satisfactory description of the data, even though the model did not include transport of water vapor.

Stable Water Isotopologue data collected during HCCT-2010

Cloud samples for the isotopic analysis were collected in the framework of the Hill Cap Cloud Thuringia 2010 (HCCT-2010) campaign on Schmücke (50° 39'N/ 10° 46'E, 937 m a.s.l.; Germany) in September and October 2010 with a three-stage Caltech Active Strand Cloudwater Collector (CASCC) during 13 different cloud events with a temporal resolution of 1 to 3 hours. In a first step, we ensured that no additional fractionation occurred during sampling with the CASCC. The d values of the three sizes classes of the CASCC (4 µm to 16 µm, 16 µm to 22 µm and >22 µm) did not differ significantly, revealing that the cloud droplets of different sizes quickly equilibrate their delta value with the one of the surrounding vapor. delta values in the cloud droplets varied from -77 per mil to -15 per mil in d2H and from -12.1 per mil to -3.9 per mil in d18O and were fitted by d2H =7.8*d18O +13*10**-3. delta values decreased with temperature as well as towards the end of the campaign, representing a seasonal trend which is known from d values in precipitation. The deuterium excess of the cloud samples was generally higher than the Local Meteoric Water Line of the closest GNIP (Global Network of Isotopes in Precipitation) station. Rain decreases its deuterium excess during falling through an unsaturated air column, while the cloud droplets conserve the deuterium excess of the initial evaporation and thus have been found to be a good indicator for the airmass source region: higher deuterium excess was measured for polar air masses and lower deuterium excess for Mediterranean air masses. Changes in d values during one cloud event were up to 3.6 per mil (d2H) and 0.23 per mil (d18O), except for frontal passages, which were associated with increases of ~6 per mil per hour (d2H) and ~0.6 per mil per hour (d18O). Using a box model, we showed that the influence of condensation only was able to explain the variation in the isotope signal of two cloud passages. Consequently, we deduced that the water vapor "feeding" the cloud advected the measured changes. A trajectory analysis and moisture source diagnostic revealed that it is very likely that the variations were either related to rain out along the trajectories or to meteorological changes in the moisture source region. This was the first study using stable water isotopologues in cloud water manifesting their potential in the context of atmospheric water vapor circulation.

Major ion concentrations in rain water and atmospheric moisture above the Atlantic Ocean

Concentratios of Cl-, Mg2+, Ca2+, and HCO3- ions were studied in rain waters and condensed atmospheric moisture above the Atlantic Ocean. Maximal number of samples was collected in the eastern tropical North Atlantic. Concentration of chloride ions ranged from 1 to 28 mg/l in rain waters (average 4.3 mg/l) and ranged from 0.3 to 2 mg/l in condensed atmospheric moisture with the average about one order of magnitude less than that for rain waters. Chloride normalized concentrations of magnesium and calcium are greater in rain waters and condensed atmospheric moisture than in ocean water due to more intensive subtraction of these ions as compared to chloride ions. Chloride normalized HCO3- concentration is one order of magnitude greater in atmospheric moisture than in seawater, possibly because of volatile component CO2 taking part in exchange between the ocean and the atmosphere.

Water harvesting for young trees using Peltier plates powered by photovoltaic solar energy

Young trees transplanted from nursery into open field require a minimum amount of soil moisture to successfully root in their new location, especially in dry-climate areas. One possibility is to obtain the required water from air moisture. This can be achieved by reducing the temperature of a surface below the air dew point temperature, inducing water vapor condensation on the surface. The temperature of a surface can be reduced by applying the thermoelectric effect, with Peltier modules powered by electricity. Here, we present a system that generates electricity with a solar photovoltaic module, stores it in a battery, and finally, it uses the electricity at the moment in which air humidity and temperature are optima to maximize water condensation while minimizing energy consumption. Also, a method to reduce the evaporation of the condensed water is proposed. The objective of the system, rather than irrigating young plants in such a degree as to boost their growth, is to maintain them alive in the dryer periods.

Water harvesting for young trees using Peltier modules powered by photovoltaic solar energy

Young trees transplanted from nursery into open field require a minimum amount of soil moisture to successfully root in their new location, especially in dry-climate areas. One possibility is to obtain the required water from air moisture. This can be achieved by reducing the temperature of a surface below the air dew point temperature, inducing water vapor condensation on the surface. The temperature of a surface can be reduced by applying the thermoelectric effect, with Peltier modules powered by electricity. Here, we present a system that generates electricity with a solar photovoltaic module, stores it in a battery, and finally, uses the electricity at the moment in which air humidity and temperature are optimal to maximize water condensation while minimizing energy consumption. Also, a method to reduce the evaporation of the condensed water is proposed. The objective of the system is to sustain young plants in drier periods, rather than exclusively irrigating young plants to boost their growth.

Análise da formulação em Monte Carlo dos pacotes de energia multiespectrais aplicada a meios constituídos por vapor d'água

The Monte Carlo method is accurate and is relatively simple to implement for the solution of problems involving complex geometries and anisotropic scattering of radiation as compared with other numerical techniques. In addition, differently of what happens for most of numerical techniques, for which the associated simulations computational time tends to increase exponentially with the complexity of the problems, in the Monte Carlo the increase of the computational time tends to be linear. Nevertheless, the Monte Carlo solution is highly computer time consuming for most of the interest problems. The Multispectral Energy Bundle model allows the reduction of the computational time associated to the Monte Carlo solution. The referred model is here analyzed for applications in media constituted for nonparticipating species and water vapor, which is an important emitting species formed during the combustion of hydrocarbon fuels. Aspects related to computer time optimization are investigated the model solutions are compared with benchmark line-by-line solutions

Reaproveitamento de condensado e vapor flash em uma planta têxtil com ênfase no setor de acabamento

This study focused object a steam generation system, steam distribution and condensate return a textile plant located in Rio Grande do Norte. The work was based on the following objectives: Knowing the use of saturated water vapor in the dyeing and finishing processes in a textile plant; To study the various aspects of a steam distribution system to identify the ways in which energy losses occur; Obtain quantitative information of the main loss in steam generation system and steam distribution and to measure the losses, water and steam system; Using the flash steam as a means of cost reduction. For it was made use of the calculation of financial gains made in their respective improvements. As a database for the development of working registers are used in industrial processes, data from utility systems, laboratory data analysis and on-line analyzers, covering the period 2013. Using the principles set conservation laws mass and energy, those data showed that the loss of water and energy in the steam system are significant and that the environmental and economic gains to be obtained with improvement actions are quite significant. Based on the data and results suggest that future studies deem the continuity approach to steam generation systems, distribution and mainly condensate return.

Premelting-Induced Smoothening of the Ice-Vapor Interface

We perform computer simulations of the quasiliquid layer of ice formed at the ice-vapor interface close to the ice Ih-liquid-vapor triple point of water. Our study shows that the two distinct surfaces bounding the film behave at small wavelengths as atomically rough and independent ice-water and water-vapor interfaces. For long wavelengths, however, the two surfaces couple, large scale parallel fluctuations are inhibited, and the ice-vapor interface becomes smooth. Our results could help explain the complex morphology of ice crystallites.

Premelting-Induced Smoothening of the Ice-Vapor Interface

We perform computer simulations of the quasi-liquid layer of ice formed at the ice/vapor interface close to the ice Ih/liquid/vapor triple point of water. Our study shows that the two distinct surfaces bounding the film behave at small wave-lengths as atomically rough and independent ice/water and water/vapor interfaces. For long wave-lengths, however, the two surfaces couple, large scale parallel fluctuations are inhibited and the ice/vapor interface becomes smooth. Our results could help explaining the complex morphology of ice crystallites.

Wave energy conversion of oscillating water column devices including air compressibility

This paper presents an investigation on air compressibility in the air chamber and its effects on the power conversion of oscillating water column (OWC) devices. As it is well known that for practical OWC plants, their air chambers may be large enough for accommodating significant air compressibility, the “spring effect,” an effect that is frequently and simply regarded to store and release energy during the reciprocating process of a wave cycle. Its insight effects on the device’s performance and power conversion, however, have not been studied in detail. This research will investigate the phenomena with a special focus on the effects of air compressibility on wave energy conversion. Air compressibility itself is a complicated nonlinear process in nature, but it can be linearised for numerical simulations under certain assumptions for frequency domain analysis. In this research work, air compressibility in the OWC devices is first linearised and further coupled with the hydrodynamics of the OWC. It is able to show mathematically that in frequency-domain, air compressibility can increase the spring coefficients of both the water body motion and the device motion (if it is a floating device), and enhance the coupling effects between the water body and the structure. Corresponding to these changes, the OWC performance, the capture power, and the optimised Power Take-off (PTO) damping coefficient in the wave energy conversion can be all modified due to air compressibility. To validate the frequency-domain results and understand the problems better, the more accurate time-domain simulations with fewer assumptions have been used for comparison. It is shown that air compressibility may significantly change the dynamic responses and the capacity of converting wave energy of the OWC devices if the air chamber is very large.

(Table 2) Composition of rain water collected over the Indian Ocean in 1967

Analytical data on the basic salt composition in evaporation products of sea (ocean) water and of rain water falling on the central area of the Indian Ocean are examined. Both hot and low-temperature (vacuum) distillation were used. When ocean water evaporates under calm conditions, sea salts in molecular-dispersed state, metamorphosed in the upper boundary layer, enter the atmosphere in addition to water vapor ("salt respiration of the ocean"). Concentration of these salts is about 0.5 mg per liter of water evaporated. Salts also enter the atmosphere from a foam-covered ocean surface as aerosols.

Silk Fibroin And Sodium Alginate Blend: Miscibility And Physical Characteristics.

Films of silk fibroin (SF) and sodium alginate (SA) blends were prepared by solution casting technique. The miscibility of SF and SA in those blends was evaluated and scanning electron microscopy (SEM) revealed that SF/SA 25/75 wt.% blends underwent microscopic phase separation, resulting in globular structures composed mainly of SF. X-ray diffraction indicated the amorphous nature of these blends, even after a treatment with ethanol that turned them insoluble in water. Thermal analyses of blends showed the peaks of degradation of pristine SF and SA shifted to intermediate temperatures. Water vapor permeability, swelling capacity and tensile strength of SF films could be enhanced by blending with SA. Cell viability remained between 90 and 100%, as indicated by in vitro cytotoxicity test. The SF/SA blend with self-assembled SF globules can be used to modulate structural and mechanical properties of the final material and may be used in designing high performance wound dressing.

Caracterização físico-química de filmes comestíveis de amido adicionado de acerola (Malphigia emarginata D.C.)

Edibles films are an alternative to synthetic materials used for packing food products. Barbados cherry is rich in vitamin C and carotenoids. The aim of this study was to characterize and develop films by casting from cassava starch, lyophilized Barbados cherry pulp and glycerol. The films were characterized with respect to thickness, water vapor permeability (WVP), water solubility, vitamin C, carotene and mechanical properties. The interaction of pulp and glycerol reduced film thickness. An increase in pulp concentration up to 60% increased WVP but beyond this concentration reduced both WVP and solubility leading to an increased level of vitamin C and β carotene in the films.

Observational Characterization of the Downward Atmospheric Longwave Radiation at the Surface in the City of Sao Paulo

This work describes the seasonal and diurnal variations of downward longwave atmospheric irradiance (LW) at the surface in Sao Paulo, Brazil, using 5-min-averaged values of LW, air temperature, relative humidity, and solar radiation observed continuously and simultaneously from 1997 to 2006 on a micrometeorological platform, located at the top of a 4-story building. An objective procedure, including 2-step filtering and dome emission effect correction, was used to evaluate the quality of the 9-yr-long LW dataset. The comparison between LW values observed and yielded by the Surface Radiation Budget project shows spatial and temporal agreement, indicating that monthly and annual average values of LW observed in one point of Sao Paulo can be used as representative of the entire metropolitan region of Sao Paulo. The maximum monthly averaged value of the LW is observed during summer (389 +/- 14 W m(-2): January), and the minimum is observed during winter (332 +/- 12 W m(-2); July). The effective emissivity follows the LW and shows a maximum in summer (0.907 +/- 0.032; January) and a minimum in winter (0.818 +/- 0.029; June). The mean cloud effect, identified objectively by comparing the monthly averaged values of the LW during clear-sky days and all-sky conditions, intensified the monthly average LW by about 32.0 +/- 3.5 W m(-2) and the atmospheric effective emissivity by about 0.088 +/- 0.024. In August, the driest month of the year in Sao Paulo, the diurnal evolution of the LW shows a minimum (325 +/- 11 W m(-2)) at 0900 LT and a maximum (345 12 W m-2) at 1800 LT, which lags behind (by 4 h) the maximum diurnal variation of the screen temperature. The diurnal evolution of effective emissivity shows a minimum (0.781 +/- 0.027) during daytime and a maximum (0.842 +/- 0.030) during nighttime. The diurnal evolution of all-sky condition and clear-sky day differences in the effective emissivity remain relatively constant (7% +/- 1%), indicating that clouds do not change the emissivity diurnal pattern. The relationship between effective emissivity and screen air temperature and between effective emissivity and water vapor is complex. During the night, when the planetary boundary layer is shallower, the effective emissivity can be estimated by screen parameters. During the day, the relationship between effective emissivity and screen parameters varies from place to place and depends on the planetary boundary layer process. Because the empirical expressions do not contain enough information about the diurnal variation of the vertical stratification of air temperature and moisture in Sao Paulo, they are likely to fail in reproducing the diurnal variation of the surface emissivity. The most accurate way to estimate the LW for clear-sky conditions in Sao Paulo is to use an expression derived from a purely empirical approach.