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1

Evaporation rate of water in hydrophobic confinement.  

PubMed

The drying of hydrophobic cavities is believed to play an important role in biophysical phenomena such as the folding of globular proteins, the opening and closing of ligand-gated ion channels, and ligand binding to hydrophobic pockets. We use forward flux sampling, a molecular simulation technique, to compute the rate of capillary evaporation of water confined between two hydrophobic surfaces separated by nanoscopic gaps, as a function of gap, surface size, and temperature. Over the range of conditions investigated (gaps between 9 and 14 ? and surface areas between 1 and 9 nm(2)), the free energy barrier to evaporation scales linearly with the gap between hydrophobic surfaces, suggesting that line tension makes the predominant contribution to the free energy barrier. The exponential dependence of the evaporation rate on the gap between confining surfaces causes a 10 order-of-magnitude decrease in the rate when the gap increases from 9 to 14 ?. The computed free energy barriers are of the order of 50 kT and are predominantly enthalpic. Evaporation rates per unit area are found to be two orders of magnitude faster in confinement by the larger (9 nm(2)) than by the smaller (1 nm(2)) surfaces considered here, at otherwise identical conditions. We show that this rate enhancement is a consequence of the dependence of hydrophobic hydration on the size of solvated objects. For sufficiently large surfaces, the critical nucleus for the evaporation process is a gap-spanning vapor tube. PMID:22392972

Sharma, Sumit; Debenedetti, Pablo G

2012-03-05

2

Instructions for measuring the rate of evaporation from water surfaces  

USGS Publications Warehouse

The ·rate of evaporation from water surfaces varies with the temperature of the water, the velocity of the wind at the water surface, and the dryness of the air. Consequently, the rate of evaporation from rivers, lakes, canals, or reservoirs varies widely in different localities and for the same locality in different seasons.

U.S. Geological Survey

1898-01-01

3

Evaporation rate as a function of water salinity  

Microsoft Academic Search

Water evaporation is an important physical phenomenon that occurs in nature and in several industrial applications. Many researchers are working in this area to establish a good correlation that can be used to measure evaporation rates precisely. In this article, we review previous experience by describing the instrument used, method of measurement, conditions of experimentation and correlations resulting from these

M. Al-Shammiri

2002-01-01

4

Evaporation rate of graphite liquid marbles: comparison with water droplets.  

PubMed

Liquid marbles are liquid drops made completely nonwetting by encapsulating the drop with a hydrophobic powder. The absence of contact with the substrate avoids contamination problems and produces high marble displacement velocities. Liquid marbles behave as microreservoirs of liquids able to move without any leakage and are promising candidates to be applied in biomedical and genetic analysis where 2D microfluidics and lab-on-a-chip methods are used. The lifetime of a liquid marble depends on the chemical nature and particle size of the hydrophobic powder as well as the liquid used to form it. There is a need for chemically inert liquid marbles, which can be used over sufficiently long periods for industrial applications. In this work, we successfully synthesized graphite liquid marbles for the first time by encapsulating graphite micropowder on water droplets and determined their evaporation periods and useful lifetimes in constant relative humidity and temperature conditions in a closed chamber. The evaporation rates of graphite liquid marbles were compared with the rates of pure water droplets in the same conditions, and it was found that they had nearly twice the lifetime of pure water droplets. The use of chemically inert graphite particles having electrical conductivity and dry lubrication properties to form a liquid marble may be a starting point for their successful use in microfluidics, genetic analysis, antifouling, wear-free micromachine, electromechanical actuator, and valve applications. PMID:19499944

Dandan, Merve; Erbil, H Yildirim

2009-07-21

5

On laboratory simulation and the evaporation rate of water on Mars  

Microsoft Academic Search

In order to better understand the stability of water on Mars, and factors likely to affect that stability, we have measured the evaporation rate of water in a CO2 atmosphere at 7 mbar and ?0°C in a large environmental chamber that minimizes fluctuation in conditions. The average evaporation rate we measured was 1.01 ± 0.19 mm\\/h. This includes correction for

Derek W. G. Sears; Shauntae R. Moore

2005-01-01

6

Flash evaporation from a water pool: Influence of the liquid height and of the depressurization rate  

Microsoft Academic Search

This article presents a study about the influence of the initial water height and of the depressurization rate on the flash evaporation of a water film. Experimental study is carried out with initial water height ranging from 25 to 250 mm, superheats between 2 and 44 K, and an initial liquid temperature from 45 to 85?°C. Visualization of the phenomenon

D. Saury; S. Harmand; M. Siroux

2005-01-01

7

Estimating steady-state evaporation rates from bare soils under conditions of high water table  

USGS Publications Warehouse

A procedure that combines meteorological and soil equations of water transfer makes it possible to estimate approximately the steady-state evaporation from bare soils under conditions of high water table. Field data required include soil-water retention curves, water table depth and a record of air temperature, air humidity and wind velocity at one elevation. The procedure takes into account the relevant atmospheric factors and the soil's capability to conduct 'water in liquid and vapor forms. It neglects the effects of thermal transfer (except in the vapor case) and of salt accumulation. Homogeneous as well as layered soils can be treated. Results obtained with the method demonstrate how the soil evaporation rates·depend on potential evaporation, water table depth, vapor transfer and certain soil parameters.

Ripple, C.D.; Rubin, J.; Van Hylckama, T.E.A

1970-01-01

8

Study of Evaporation Rate of Water in Hydrophobic Confinement using Forward Flux Sampling  

NASA Astrophysics Data System (ADS)

Drying of hydrophobic cavities is of interest in understanding biological self assembly, protein stability and opening and closing of ion channels. Liquid-to-vapor transition of water in confinement is associated with large kinetic barriers which preclude its study using conventional simulation techniques. Using forward flux sampling to study the kinetics of the transition between two hydrophobic surfaces, we show that a) the free energy barriers to evaporation scale linearly with the distance between the two surfaces, d; b) the evaporation rates increase as the lateral size of the surfaces, L increases, and c) the transition state to evaporation for sufficiently large L is a cylindrical vapor cavity connecting the two hydrophobic surfaces. Finally, we decouple the effects of confinement geometry and surface chemistry on the evaporation rates.

Sharma, Sumit; Debenedetti, Pablo G.

2012-02-01

9

Soil Effect on the Evaporation Rate of Pure Water Ice Under Martian Conditions  

Microsoft Academic Search

In order to understand the possibility of increasing the likelihood of liquid water on the surface of ice on Mars, we have measured the effect of a 0-10 cm dust layer. We find that such a layer decreases the evaporation rate by a factor of 5.

J. D. Chittenden; D. W. G. Sears; V. Chevrier; J. Hanley; L. A. Roe

2006-01-01

10

Effect of Thickness of a Water Repellent Soil Layer on Soil Evaporation Rate  

NASA Astrophysics Data System (ADS)

A water repellent soil layer overlying wettable soil is known to affect soil evaporation. This effect can be beneficial for water conservation in areas where water is scarce. Little is known, however, about the effect of the thickness of the water repellent layer. The thickness of this layer can vary widely, and particularly after wildfire, with the soil temperature reached and the duration of the fire. This study was conducted to investigate the effect of thickness of a top layer of water repellent soil on soil evaporation rate. In order to isolate the thickness from other possible factors, fully wettable standard sand (300~600 microns) was used. Extreme water repellency (WDPT > 24 hours) was generated by 'baking' the sand mixed with oven-dried pine needles (fresh needles of Pinus densiflora) at the mass ratio of 1:13 (needle:soil) at 185°C for 18 hours. The thicknesses of water repellent layers were 1, 2, 3 and 7 cm on top of wettable soil. Fully wettable soil columns were prepared as a control. Soil columns (8 cm diameter, 10 cm height) were covered with nylon mesh. Tap water (50 ml, saturating 3 cm of a soil column) was injected with hypoderm syringes from three different directions at the bottom level. The injection holes were sealed with hot-melt adhesive immediately after injection. The rate of soil evaporation through the soil surface was measured by weight change under isothermal condition of 40°C. Five replications were made for each. A trend of negative correlation between the thickness of water repellent top layer and soil evaporation rate is discussed in this contribution.

Ahn, S.; Im, S.; Doerr, S.

2012-04-01

11

METABOLIC RATE AND EVAPORATIVE WATER LOSS OF MEXICAN SPOTTED AND GREAT HORNED OWLS  

Microsoft Academic Search

AaSraAcr. -We measured rates of oxygen consumption and evaporative water loss (EWL) of Mexican Spotted (Strix occidentalis lucida) and Great Homed (Bubo virginianus) owls in Arizona. Basal metabolic rate averaged 0.84 ccO,gl .h-' for the Spotted Owl and 0.59 cc0, .g- I h- ' for the Great Homed Owl, with apparent thermoneutral zones extending from 17.0-25.2\\

JOSEPH L. GANIZY; RUSSELL P. BALDA; RUDY M. KINGS

1993-01-01

12

Oil shale process water evaporation  

SciTech Connect

The primary objectives of this research program were to study chemical, microclimatological, and interactive effects on the evaporation of low-quality oil shale process wastewaters to develop more applicable evaporation models and evaporation design criteria for the disposal of oil shale process waters and to analyze the processes associated with the release of potentially toxic emissions from these low-quality effluents. The research program incorporated field and laboratory studies analyzing microclimatic and chemical effects on the evaporation of oil shale process wastewaters. Field studies at Laramie, Wyoming were designed to continuously monitor microclimatological conditions and the evaporation from three low-quality effluents using Class A evaporation pans. Fresh water evaporation was monitored as a control. Process waters were routinely monitored for concentrations of organic and inorganic constituents. Laboratory studies were designed to isolate and describe significant climatic, chemical, and interactive effects on evaporation rates. Results from the above studies were utilized to develop a regression model to predict evaporation from these low quality effluents. This model was then compared to commonly utilized models to estimate evaporation. A stochastic model was developed using a first order markov process to generate 1000 20-year climatological records. Mass balance techniques were then used to evaluate the new data sets for evaporation processes and determine critical design parameters for evaporation disposal ponds. Laboratory studies were conducted to determine significant effects on the Henry's Law Constant for eight organic compounds in two process waters. 69 refs., 16 figs., 51 tabs.

Hasfurther, V.R.; Reeves, T.

1990-01-01

13

Hypotheses of calculation of the water flow rate evaporated in a wet cooling tower  

SciTech Connect

The method developed by Poppe at the University of Hannover to calculate the thermal performance of a wet cooling tower fill is presented. The formulation of Poppe is then validated using full-scale test data from a wet cooling tower at the power station at Neurath, Federal Republic of Germany. It is shown that the Poppe method predicts the evaporated water flow rate almost perfectly and the condensate content of the warm air with good accuracy over a wide range of ambient conditions. The simplifying assumptions of the Merkel theory are discussed, and the errors linked to these assumptions are systematically described, then illustrated with the test data.

Bourillot, C.

1983-08-01

14

Solvent Evaporation Rates  

Microsoft Academic Search

A system of equations for predicting the evaporation rates of solvents is presented. These equations may be used by the industrial hygienist, in conjunction with the diffusion equations developed elsewhere, to predict the atmospheric concentrations of vapors from spilled toxic liquids. The equations are derived from wind tunnel tests and applied to predictions for spills both indoors and outdoors.

DOUGLAS C. GRAY

1974-01-01

15

An experimental investigation on the effects of surface gravity waves on the water evaporation rate in different air flow regimes  

NASA Astrophysics Data System (ADS)

Estimating rate of evaporation from undisturbed water surfaces to moving and quiet air has been the topic a vast number of research activities. The obvious presence of various shapes of gravity waves on the water body surfaces was the motivation of this experimental investigation. In this investigation experimental measurements have been done to quantify evaporation rate from wavy water surfaces in free, mixed and forced convection regimes. The effects of a wide range of surface gravity waves from low steepness, round shaped crest with slow celerity, to steep and very slight spilling crest waves, on the water evaporation rate have been investigated. A wide range of {{Gr}}/{{Re}}2 (0.01 ? {{Gr}}/{{Re}}2 ? 100) was achieved by applying different air flow velocities on a large heated wave flume equipped with a wind tunnel. Results reveal that wave motion on the water surface increase the rate of evaporation for all air flow regimes. For free convection, due to the effect of wave motion for pumping rotational airflows at the wave troughs and the dominant effect of natural convection for the air flow advection, the maximum evaporation increment percentage from wavy water surface is about 70 %. For mixed and forced convection, water evaporation rate increment is more sensitive to the air flow velocity for the appearance of very slight spilling on the steep wave crests and the leeward air flow structures.

Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

2013-08-01

16

Role of Water Activity of Liquid in Controlling Evaporation Rate of Low-Viscosity Liquids  

Microsoft Academic Search

Viscosity of liquid is normally the most critical factor when operating an evaporator in an industrial process. This study shows that the dewatering capacity during evaporation for a low-viscosity peptone solution was reduced 40% for water activity (aw) = 0.8 and 80% for aw = 0.45. Designers of evaporators should be aware of this phenomenon if the aim is to get a high degree

Øistein Høstmark; Sigurd Teigland

2009-01-01

17

Evaporation rate of water as a function of a magnetic field and field gradient.  

PubMed

The effect of magnetic fields on water is still a highly controversial topic despite the vast amount of research devoted to this topic in past decades. Enhanced water evaporation in a magnetic field, however, is less disputed. The underlying mechanism for this phenomenon has been investigated in previous studies. In this paper, we present an investigation of the evaporation of water in a large gradient magnetic field. The evaporation of pure water at simulated gravity positions (0 gravity level (ab. g), 1 g, 1.56 g and 1.96 g) in a superconducting magnet was compared with that in the absence of the magnetic field. The results showed that the evaporation of water was indeed faster in the magnetic field than in the absence of the magnetic field. Furthermore, the amount of water evaporation differed depending on the position of the sample within the magnetic field. In particular, the evaporation at 0 g was clearly faster than that at other positions. The results are discussed from the point of view of the evaporation surface area of the water/air interface and the convection induced by the magnetization force due to the difference in the magnetic susceptibility of water vapor and the surrounding air. PMID:23443127

Guo, Yun-Zhu; Yin, Da-Chuan; Cao, Hui-Ling; Shi, Jian-Yu; Zhang, Chen-Yan; Liu, Yong-Ming; Huang, Huan-Huan; Liu, Yue; Wang, Yan; Guo, Wei-Hong; Qian, Ai-Rong; Shang, Peng

2012-12-11

18

Experimental Determination of the Kinetic Coefficients for Water Using Nucleation and Evaporation Rates: Sensitivity to Vapor Pressure  

Microsoft Academic Search

If we are to understand the growth\\/evaporation rates, nucleation rates, and activation rates of atmospheric aerosol particles, we must have an understanding of the kinetics of mass and energy exchange between the surface of an aerosol particle and the surrounding gas. Laboratory experiments to determine the thermal accommodation alpha t coefficient and condensation coefficient alpha c of liquid water have

R. A. Shaw; D. Lamb

2001-01-01

19

Characteristics of Evaporation Rate of Water in Superheated Steam and Air  

NASA Astrophysics Data System (ADS)

Superheated steam drying and highly humid air drying have been applied in many industrial drying fields, such as drying of by-products of food industry. The most significant reason for this wide range of applications of superheated steam is that more water evaporates in this steam or highly humid air than in dry air above the inversion point temperature. As compared with these wide practical applications, fundamental research for determining controlled operating conditions or optimum design conditions for a superheated steam drying system have not been sufficiently performed. From this viewpoint, in experimenting for drying water in the closed circuit dryer, by changing drying variables, such as the mass velocity of heat transfer of the steam,the existance of the inversion point temperature was confirmed and the locus of the temperature were found. The behavior of the locus enables one to specify the drying variables for a controlled drying system. The difference of the evaporation phenomenon between superheated steam drying and conventional air drying was examined from the heat convection standpoint. The reliability of the data obtained from the experiment was too checked by comparing the data with another reported data.

Nomura, Tomihiro; Nishimura, Nobuya; Hyodo, Tsutomu; Kashiwagi, Takao

20

Evaporation rates for liquid clusters  

Microsoft Academic Search

An expression for the evaporation rate of neutral atoms from a hot liquid cluster is suggested. It combines Weisskopf's statistical model with a level density that is derived from the experimentally known free energy of a macroscopic droplet of the cluster material. For the case of sodium clusters, it is compared with the rate based on the level density of

S. Frauendorf

1995-01-01

21

Evaporation rate of nucleating clusters.  

PubMed

The Becker-Döring kinetic scheme is the most frequently used approach to vapor liquid nucleation. In the present study it has been extended so that master equations for all cluster configurations are included into consideration. In the Becker-Döring kinetic scheme the nucleation rate is calculated through comparison of the balanced steady state and unbalanced steady state solutions of the set of kinetic equations. It is usually assumed that the balanced steady state produces equilibrium cluster distribution, and the evaporation rates are identical in the balanced and unbalanced steady state cases. In the present study we have shown that the evaporation rates are not identical in the equilibrium and unbalanced steady state cases. The evaporation rate depends on the number of clusters at the limit of the cluster definition. We have shown that the ratio of the number of n-clusters at the limit of the cluster definition to the total number of n-clusters is different in equilibrium and unbalanced steady state cases. This causes difference in evaporation rates for these cases and results in a correction factor to the nucleation rate. According to rough estimation it is 10(-1) by the order of magnitude and can be lower if carrier gas effectively equilibrates the clusters. The developed approach allows one to refine the correction factor with Monte Carlo and molecular dynamic simulations. PMID:22112089

Zapadinsky, Evgeni

2011-11-21

22

Evaporation  

NSDL National Science Digital Library

This three-part activity consists of an activity that groups of learners develop themselves, a given procedure, and an optional demonstration. First, learners discuss examples of evaporation and then design and conduct their own test to find out whether heating water has an effect on the rate of evaporation. While waiting for their results, learners conduct another evaporation activity using single drops of water on 2 paper towels, one of which is heated. The optional demonstration compares the rate of evaporation of hot and cold water using a sensitive scale or balance. In each of these experiences with evaporation, learners will identify variables, consider how to best control them, and use their observations to conclude that heating water increases the rate of evaporation.

Kessler, James H.; Galvan, Patricia M.

2007-01-01

23

Rate of runaway evaporative cooling  

SciTech Connect

Evaporative cooling is a process that is essential in creating Bose-Einstein condensates in dilute atomic gasses. This process has often been simulated based on a model using a truncated Boltzmann distribution. This model assumes that the energy distribution up to the threshold energy can still be described by a Boltzmann distribution: it assumes detailed balance up to the threshold energy. However, the evolution of the distribution function in time is not taken into account. Here we solve the kinetic Boltzmann equation for a gas undergoing evaporative cooling in a harmonic and linear trap in order to determine the evolution of the energy distribution. The magnitude of the discrepancy with the truncated Boltzmannmodel is calculated by including a polynomial expansion of the distribution function. We find that up to 35% fewer particles are found in the high-energy tail of the distribution with respect to the truncated Boltzmann distribution and up to 15% more collisions are needed to reach quantum degeneracy. Supported by a detailed investigation of the particle loss rate at different energies, we conclude that the limited occupation of high-energy states during the evaporation process causes the lowering of the evaporation speed and efficiency.

Groep, J. van de; Straten, P. van der; Vogels, J. M. [Atom Optics and Ultrafast Dynamics, Utrecht University, P.O. Box 80, 000, NL-3508 TA Utrecht (Netherlands)

2011-09-15

24

Increasing the evaporation rate for fresh water production—Application to energy saving in renew able energy sources  

Microsoft Academic Search

This paper is centered on the study of the energy saving in the obtaining of drinking water from salty or contaminated water by reduction of the latent heat of evaporation. This is procured by a reduction of the surface tension of the liquid mixture by adding nonvolatile surfactants to the water to be distilled. It has been proven that there

C. Armenta-Deu

1997-01-01

25

Water evaporation on highly viscoelastic polymer surfaces.  

PubMed

Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film. PMID:22647193

Pu, Gang; Severtson, Steven J

2012-06-19

26

Evaporation of water droplets containing carbon nanotubes  

NASA Astrophysics Data System (ADS)

The evaporation of water droplets containing carbon nanotubes has been experimentally studied. The droplets were evaporated in a flow of dry air at temperatures in a range of T 0 = 20-200°C and Reynolds numbers designed on the initial diameter were Re = 500-2000. The results of measurements of the droplet surface temperature and evaporation rate show that the addition of ˜0.1 wt % nanoparticles to the base liquid (water) virtually does not change the laws of heat and mass transfer.

Terekhov, V. I.; Shishkin, N. E.

2012-01-01

27

Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure  

Microsoft Academic Search

This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written responses and to further probe their understandings of the questions asked in

Nurtaç Canpolat

2006-01-01

28

Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure  

ERIC Educational Resources Information Center

This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

Canpolat, Nurtac

2006-01-01

29

Quantifying nonisothermal subsurface soil water evaporation  

NASA Astrophysics Data System (ADS)

Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB.

Deol, Pukhraj; Heitman, Josh; Amoozegar, Aziz; Ren, Tusheng; Horton, Robert

2012-11-01

30

Experimental study on isotopic fractionation factor and evaporation rate  

Microsoft Academic Search

Isotopic fractionation is the foundation of tracing water cycle using hydrogen and oxygen isotopes. Isotopic fractionation factors in evaporation from free water body are mainly affected by temperature and relative humidity, and greatly vary with these atmospheric factors in a day. Evaporation rate can properly reveal the effects of atmospheric factors. Therefore, there should be a certain function relationship existing

T. Wang; W. Bao; H. Hu; S. Qu; Z. Yu

2009-01-01

31

Evaporation of water from agitated freezing slurries at low pressure  

Microsoft Academic Search

In an absorptive vacuum freezing process, water evaporates from the freezing solution and condenses on a cold salt solution. Given sufficient condensing capacity, the evaporation rate will be controlled by the freezing solution vapor pressure. The size of the condensing equipment which matches a given evaporation system can be estimated using rate measurements made with low vapor pressure freezing solutions.

L. C. Dickey

1996-01-01

32

Fuel evaporation rate in intense recirculation zones  

Microsoft Academic Search

An expression is derived for the mean liquid fuel concentration in a flow region with intense recirculation rates. The expression makes it possible to evaluate liquid fuel evaporation rates. Finite fuel concentrations are predicted even for residence times greater than the critical value for single drops. The mean fuel evaporation rate may, therefore, be significantly smaller than that for single

I. T. Osgerby

1975-01-01

33

New Instrument for Measuring Evaporation; Application to Evaporation of Water through Thin Films  

Microsoft Academic Search

A new instrument quickly and accurately determines evaporation rates of water. A probe passes helium over a small area of the water surface; the vapor picked up by the helium returns through the probe and is continuously measured by a thermal conductivity cell. Accuracy and repeatability are within 1% absolute. The apparatus is sensitive to a change in evaporation rate

Donald C. Walker

1963-01-01

34

Direct Observation of Evaporation from Quiescent Water  

Microsoft Academic Search

The color change of a filter paper impregnated with cobaltous chloride and held just above the surface of water gives a good indication of the rate at which evaporation proceeds from individual regions of the surface. The marked effect of some monolayers on thermal convection currents within the liquid can be thus shown.

Karol J. Mysels

1959-01-01

35

Wettability and the evaporation rates of fluids from solid surfaces  

Microsoft Academic Search

The interfacial forces which determine the interaction between a fluid and a solid surface have been investigated under dynamic conditions. The evaporation characteristics of fluid drops placed on solid surfaces have also been investigated. The rate of evaporation of drops of liquids placed on smooth solid surfaces with wetting characteristics, i.e. contact angle, , < 90° (water on glass), was

K. S. Birdi; D. T. Vu

1993-01-01

36

Experimental comparison of the ability of Dalton based and similarity theory correlations to predict water evaporation rate in different convection regimes  

NASA Astrophysics Data System (ADS)

This paper investigates the ability of two widely used evaporation models: Dalton based correlations and similarity theory results by comparing with experimental measurements. A series of experimental investigations are carried out over a wide range of water temperatures and air velocities for 0.01 ? Gr/ Re 2 ? 100 in a rectangular heated pool. The results show that for forced convection regime satisfactory results can be achieved by using the modified Dalton correlations, while, due to ripples appear on the water free surface, similarity theory under predicts the evaporation rate. In the free convection regime, Dalton based correlations even with modification are not able to predict acceptable results. For mixed convection regime, although both the similarity theory and Dalton based correlations without modification are not able to predict the mild non-linearity behavior between water evaporation rate and vapor pressure difference, but they obtain relatively satisfactory results. A dimensionless correlation using the experimental data of all convection regimes is proposed to cover different water surface geometries and air flow conditions.

Jodat, Amin; Moghiman, Mohammad; Anbarsooz, Morteza

2012-08-01

37

EVAPORATION FROM SHALLOW WATER TABLE THROUGH LAYERED SOIL PROFILES  

Microsoft Academic Search

The purpose of this study is to estimate the steady state evaporation rates from layered soils in the presence of high water table under isothermal conditions. A finite difference numerical scheme based upon the one-dimensional Richards equation has been employed to estimate the evaporation rates from a two-layered soil profile overlying a shallow water for appropriate initial and boundary conditions.

C. P. Kumar

1999-01-01

38

Evaporation  

NSDL National Science Digital Library

The representation is an animation of the water cycle. It shows water evaporating from a large body of water with a descriptive text describing the water cycle process including evaporation, condensation and precipitation. An additional diagram on transport is included.

39

Flash evaporation from turbulent water jets  

Microsoft Academic Search

Results of an experimental investigation of flash evaporation from turbulent planar and axisymmetric water jets are reported. In the range of jet thicknesses tested, for planar jets, due to shattering, evaporation is found to be nearly independent of the jet thickness. Evaporation from the planar jets was found to be dependent on the initial level of turbulence in the water

D. Bharathan; T. Penney

1983-01-01

40

Flash evaporation from turbulent water jets  

Microsoft Academic Search

Results of an experimental investigation of flash evaporation from turbulent planar and axisymmetric water jets are reported. In the range of jet thicknesses tested, for planar jets, due to shattering, evaporation if found to be nearly independent of the jet thickness. Evaporation from the planar jets was found to be dependent on the initial level of turbulence in the water

D. Bharathan; T. Penney

1984-01-01

41

Flash Evaporation from Turbulent Water Jets.  

National Technical Information Service (NTIS)

Results of an experimental investigation of flash evaporation from turbulent planar and axisymmetric water jets are reported. In the range of jet thicknesses tested, for planar jets, due to shattering, evaporation is found to be nearly independent of the ...

D. Bharathan T. Penney

1983-01-01

42

Vegetation Cover Decreases Evaporative Water Loss in a Wetland Ecosystem  

NASA Astrophysics Data System (ADS)

Analysis of oxygen and hydrogen isotope ratios of water is a useful tool for quantitative measurements of water evaporation. Water molecules with the lighter isotopes, H216O, evaporate faster than H218O and DH16O, leaving the residual water enriched in D and 18O. Therefore, the greater the evaporation, the higher the ?18O and ?D values in the remaining water body. Here we used stable isotope analyses to study evaporative processes in the a wetland water conservation area (WCA-1, South Florida Water Management District) where the primary purpose is to conserve regional water resources. Evaporation is one of the major paths of water loss in WCA-1. We collected water from 50 sampling stations located in the 145,920 acres of WCA-1 area for the months of August, September, and November 2006 and January 2007. Water samples were analyzed for oxygen and hydrogen isotope ratios. The results confirm that the water in this area is enriched by evaporation since a plot of water ?D versus ?18O lies off the meteoric water line. However, the enrichment of 18O and D within WCA-1 is not homogeneous, with differences in ?18O values between stations of up to 2‰. We GIS mapped the ?18O values of water for the entire area and found the isotopic enrichment pattern is consistent through time. This result suggests that water at different locations in WCA-1 has different evaporation rates. Possible factors that contribute to this evaporation pattern are: distance to the peripheral canal discharge station, water depth, and vegetation coverage. To find out which is (are) the determining factor(s) affecting water evaporation of the area, we mapped ?18O values of water with elevation and vegetation type of WCA-1 and calculated average elevation and percentage of vegetation coverage of a 100m2 area around each sampling station. A multiple linear regression between ?18O values of water and average distance from the discharge gates, elevation, and percentage coverage indicate that the observed evaporation pattern is not caused by water depth. Distance from the discharge gates and percentage vegetation coverage are both significantly correlated with ?18O values of water. The effect of distance is related to the water turnover rate, i.e. the further the location is to a discharge station the greater the time the water at that location has been exposed to evaporation. In contrast, the higher the vegetation coverage the lower the loss of water through evaporation. In the future, we will determine if the effect of vegetation coverage in diminishing water loss by evaporation is annulled by the loss through transpiration.

Wang, X.; Sternberg, L. O.; Miralles-Wilhelm, F. R.

2007-12-01

43

Condensation and evaporation of water vapor in mixed aerosols of liquid droplets and ice: numerical comparison of growth rate expressions  

Microsoft Academic Search

We compare four different H2O mass flux descriptions in simulations of the evolution of mixed water\\/ice aerosol populations undergoing condensational growth. It is shown that the Maxwellian description, ignoring condensation heat release, overestimates the growth rates severely when compared with an exact numerical description. The well-known Mason equation predicts the growth rates somewhat better, but still in an inadequate manner

Jukka Hienola; Markku Kulmala; Ari Laaksonen

2001-01-01

44

Water Purification by Evaporation and Condensation  

NSDL National Science Digital Library

This demonstration illustrates how the water cycle helps to purify water. Students are introduced to the key terms, which are evaporation and condensation. They discover that evaporation is defined as the process through which a liquid becomes a vapor, while condensation is simply the reverse. Students also learn that in the case of water, the main mechanisms for evaporation and condensation are heating and cooling, respectively.

45

Pan Evaporation Trends and the Terrestrial Water Balance. I. Principles and Observations  

Microsoft Academic Search

Pan evaporation is just that - it is the evaporation rate of water from a small dish located at the ground-surface. Pan evaporation is a measure of the evaporative demand over terrestrial surfaces. Declines in pan evaporation have now been reported in many regions of the world. The trends vary from one pan to the next, but when averaged over

Michael L. Roderick; Michael T. Hobbins; Graham D. Farquhar

2009-01-01

46

Evaporation rate of nucleating clusters  

Microsoft Academic Search

The Becker-Do¨ring kinetic scheme is the most frequently used approach to vapor liquid nucleation. In the present study it has been extended so that master equations for all cluster configurations are included into consideration. In the Becker-Do¨ring kinetic scheme the nucleation rate is calculated through comparison of the balanced steady state and unbalanced steady state solutions of the set of

Evgeni Zapadinsky

2011-01-01

47

A calorimeter for measuring liquid evaporation rates  

Microsoft Academic Search

Describes a simple calorimetric procedure which allows the measurement of evaporation rates of liquids over a range of temperatures and hydrodynamic conditions. The method is rapid, its accuracy is about +or-3% and it may be used with small volumes of sample (100 mu l and less). Results obtained for a representative group of substances are presented.

C. A. Reading; A. Reiser

1977-01-01

48

Surface acoustic wave measurements of evaporation rate  

Microsoft Academic Search

Measurements of the surface acoustic wave (SAW) attenuation versus time have been performed in liquids with a relatively high evaporation rate (acetone, ethyl acetate, etc.). The linear dependence of the SAW attenuation versus time has been observed. The possibility of determining the ‘unknown’ molecular mass of the liquid from the SAW attenuation versus time dependence is presented. The special experimental

Pavol Koštial

1996-01-01

49

Evaporation rate of volatile liquids. Final report, Second edition  

Microsoft Academic Search

The research was designed to determine whether the evaporation rate of a volatile liquid could be adequately predicted from its common 'handbook' properties over a narrow range of environmental conditions. An experimental apparatus to measure the evaporation rate under controlled conditions and nearly ideal presentation of the evaporation surface to the controlled airflow was developed. The evaporation rate for a

K. O. Braun; K. J. Caplan

1989-01-01

50

Water Evaporation and Conformational Changes from Partially Solvated Ubiquitin  

PubMed Central

Using molecular dynamics simulation, we study the evaporation of water molecules off partially solvated ubiquitin. The evaporation and cooling rates are determined for a molecule at the initial temperature of 300?K. The cooling rate is found to be around 3?K/ns, and decreases with water temperature in the course of the evaporation. The conformation changes are monitored by studying a variety of intermediate partially solvated ubiquitin structures. We find that ubiquitin shrinks with decreasing hydration shell and exposes more of its hydrophilic surface area to the surrounding.

Thirumuruganandham, Saravana Prakash; Urbassek, Herbert M.

2010-01-01

51

Evaporation Rate of Liquid Helium. I  

Microsoft Academic Search

In connection with a study of the emissivity of metals at low temperatures, a quantitative analysis has been made of the factors involved in the design of storage containers for liquid helium. Experiments confirm the analysis, which has resulted in an exceedingly simple liquid-nitrogen-protected liquid helium container having a helium evaporation rate of 1 percent per day.The hemispherical emissivity of

Aaron Wexler

1951-01-01

52

Experimental determination of sodium evaporation rates. [LMFBR  

Microsoft Academic Search

Sodium evaporation rates from Karlsruhe Nuclear Research Center-NALA experiments (experiments on aerosol release from a contaminated sodium pool into an argon or a nitrogen atmosphere) are presented. Pool temperatures were varied between 700 and 1000 K at different geometrical and convective conditions. Technical scale experiments with a 531-cm² pool surface area were performed at natural convection in a 2.2-m³ heated

W. Schuetz; H. Sauter

1982-01-01

53

A study of the Sherwood–Rayleigh relation for water undergoing natural convection-driven evaporation  

Microsoft Academic Search

An experimental study is presented of evaporative free-surface natural convection. A power law relationship is developed between the Sherwood number for evaporation (Sh) and the Rayleigh number for air-side natural convection (Ra). Evaporation of water was investigated in sixteen different tanks having four depths and four widths. Evaporation rates and the relevant temperatures and relative humidity were measured, from which

S. M. Bower; J. R. Saylor

2009-01-01

54

Investigation of the effect of dissolved salts, soil layers, and wind on the evaporation rate of water on Mars  

Microsoft Academic Search

Laboratory simulation experiments have been performed to study the stability of water under martian conditions. The first chapter of this thesis is a background introduction into the history of Mars and a description of the evidence for past and present water on Mars. The second chapter describes experiments that were performed on low concentration brine solutions, but were never published.

Julie Diane Chittenden

2007-01-01

55

Evaporation from soil in relation to residue rate, mixing depth, soil texture and evaporativity  

Microsoft Academic Search

The role of crop residues as a surface mulch on evaporation has been widely studied. But information on evaporation and its reduction by crop residues mixed in surface soil to different depths particularly in relation to soil texture and evaporativity (Eo) is lacking. We studied the effect of four rates of paddy straw, viz. 0, 2, 4 and 8 Mg

B. S. Gill; S. K. Jalota

1996-01-01

56

242-A Evaporator water hammer event investigation  

Microsoft Academic Search

On February 28, 1992, at approximately 1053 hours, a water hammer occurred at the 242-A Evaporator Facility located in the 200 East Area of the Hanford Site. The facility's Raw Water\\/Used Raw Water (RW\\/URW) system was undergoing operational testing at the time of the event. While trying to establish system water pressure, a downstream pressure control valve was overcome by

1992-01-01

57

242-A Evaporator water hammer event investigation  

Microsoft Academic Search

On February 28, 1992, at approximately 1053 hours, a water hammer occurred at the 242-A Evaporator Facility located in the 200 East Area of the Hanford Site. The facility`s Raw Water\\/Used Raw Water (RW\\/URW) system was undergoing operational testing at the time of the event. While trying to establish system water pressure, a downstream pressure control valve was overcome by

1992-01-01

58

Thermal effects of the substrate on water droplet evaporation  

NASA Astrophysics Data System (ADS)

We experimentally investigate the behavior of a pinned water droplet evaporating into air. The influence of the substrate temperature and substrate thermal properties on the evaporation process are studied in both hydrophilic and hydrophobic conditions. Our objective is to understand the effect of thermal mechanisms on the droplet evaporation process. The experimental results are compared with the quasisteady, diffusion-driven evaporation model, which is implemented under the influence of the temperature; the model assumes the isothermia of the droplet at the substrate temperature. The results highlight a favorable correlation between the model and the experimental data at ambient temperatures for most situations considered here. The model works to qualitatively describe the influence of the substrate temperature on the evaporation process. However, with an increase in the substrate temperature, the role of the thermal-linked mechanisms becomes increasingly important; this experiment highlights the need for more accurate models to account for the buoyant convection in vapor transport and the evaporative cooling and heat conduction between the droplet and the substrate. Finally, the experimental data reveal the modification of contact angle evolution as the temperature increases and the crucial role played by the nature of the substrate in the evaporation of a sessile droplet. The influence of the substrate thermal properties on the global evaporation rate is explained by the parallel thermal effusivity of the liquid and solid phases.

Sobac, B.; Brutin, D.

2012-08-01

59

Thermal effects of the substrate on water droplet evaporation.  

PubMed

We experimentally investigate the behavior of a pinned water droplet evaporating into air. The influence of the substrate temperature and substrate thermal properties on the evaporation process are studied in both hydrophilic and hydrophobic conditions. Our objective is to understand the effect of thermal mechanisms on the droplet evaporation process. The experimental results are compared with the quasisteady, diffusion-driven evaporation model, which is implemented under the influence of the temperature; the model assumes the isothermia of the droplet at the substrate temperature. The results highlight a favorable correlation between the model and the experimental data at ambient temperatures for most situations considered here. The model works to qualitatively describe the influence of the substrate temperature on the evaporation process. However, with an increase in the substrate temperature, the role of the thermal-linked mechanisms becomes increasingly important; this experiment highlights the need for more accurate models to account for the buoyant convection in vapor transport and the evaporative cooling and heat conduction between the droplet and the substrate. Finally, the experimental data reveal the modification of contact angle evolution as the temperature increases and the crucial role played by the nature of the substrate in the evaporation of a sessile droplet. The influence of the substrate thermal properties on the global evaporation rate is explained by the parallel thermal effusivity of the liquid and solid phases. PMID:23005772

Sobac, B; Brutin, D

2012-08-20

60

Undersaturation dependence of the evaporation rate of potassium chloride  

Microsoft Academic Search

Theories of ledge dynamics for crystals evaporating by the stepwise mechanism predict a change from crystal edge control to dislocation control of the evaporation kinetics as the gas phase saturation is reduced. This effect was studied by measuring the rate of evaporation from the (100) face of high purity KCl crystals vs gas phase saturation with a specially designed spherical

Paul C. Nordine; Paul W. Gilles

1981-01-01

61

Soil water evaporation and crop residues  

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop residues have value when left in the field and also when removed from the field and sold as a commodity. Reducing soil water evaporation (E) is one of the benefits of leaving crop residues in place. E was measured beneath a corn canopy at the soil suface with nearly full coverage by corn stover...

62

Predicting evaporation rates and times for spills of chemical mixtures  

Microsoft Academic Search

Spreadsheet and short-cut methods have been developed for predicting evaporation rates and evaporation times for spills and constrained baths of chemical mixtures. Steady-state and time-varying predictions of evaporation rates can be made for six-component mixtures, including liquid-phase non-idealities as expressed through the UNIFAC method for activity coefficients. A group-contribution method is also used to estimate vapor-phase diffusion coef- ficients, which

RAYMOND L. SMITH

2001-01-01

63

242-A Evaporator water hammer event investigation  

SciTech Connect

On February 28, 1992, at approximately 1053 hours, a water hammer occurred at the 242-A Evaporator Facility located in the 200 East Area of the Hanford Site. The facility's Raw Water/Used Raw Water (RW/URW) system was undergoing operational testing at the time of the event. While trying to establish system water pressure, a downstream pressure control valve was overcome by water pressure and abruptly shut. Approximately 2300 gal/min of raw water flow was established before the valve closed. Supply water pressure was determined to be approximately 105 psig. During preliminary damage assessments a pressure gauge was found overranged and water was observed leaking from various components. Detailed evaluations are being conducted to assess potential damage to the EC-1 Condenser and other equipment associated with the RW/URW systems.

Wegener, D.L.

1992-04-01

64

242-A Evaporator water hammer event investigation  

SciTech Connect

On February 28, 1992, at approximately 1053 hours, a water hammer occurred at the 242-A Evaporator Facility located in the 200 East Area of the Hanford Site. The facility`s Raw Water/Used Raw Water (RW/URW) system was undergoing operational testing at the time of the event. While trying to establish system water pressure, a downstream pressure control valve was overcome by water pressure and abruptly shut. Approximately 2300 gal/min of raw water flow was established before the valve closed. Supply water pressure was determined to be approximately 105 psig. During preliminary damage assessments a pressure gauge was found overranged and water was observed leaking from various components. Detailed evaluations are being conducted to assess potential damage to the EC-1 Condenser and other equipment associated with the RW/URW systems.

Wegener, D.L.

1992-04-01

65

Surface wetness limit high evaporation rates from porous media into convective air flows  

NASA Astrophysics Data System (ADS)

Evaporation rate from a porous media reflect a balance between energy input and mass transfer to adjacent air (atmospheric demand) and internal transport mechanisms. For moderate atmospheric demand (<6 mm/day) a constant evaporation rate period is observed (termed stage-1) in which the evaporative flux is supplied by capillary flow from the receding drying front to the surface. Interestingly, increasing atmospheric demand (e.g., higher convective air stream) results in a gradual decrease in evaporation rate during stage-1. Hence, for similar surface water contents the relative evaporation rate decreases under high atmospheric demand. We extended the formulation of Suzuki and Maeda [1968] from static diffusion-convection at the surface adding links with internal transport mechanisms to account for gradual surface drying. Experiments in wind tunnel support the transition in surface wetness to simultaneously accommodate the atmospheric demand with porous media supply rates. The resulting balance is reflected by evaporation rate lower than potential rate over free water surface and different dynamic equilibrium states are reversible as confirmed experimentally. We conducted high resolution Infrared imaging (IR) to identify the structure and persistence of evaporative sites that support the equilibrium evaporation rate. The results are potentially useful for modern numerical models that couple surface and atmospheric flows at small scales, and could be useful for devising efficient drying strategies in industrial applications.

Shahraeeni, E.; Or, D.

2010-12-01

66

The fate of evaporated water from the Ganges basin  

NASA Astrophysics Data System (ADS)

This research studies river basin moisture recycling rates in order to determine the atmospheric part of the water cycle and the influence of the land surface there on. For river basins in India (Ganges and Indus), the fraction of evaporation that falls again as precipitation in the same river basin (the moisture recycling) is determined. Furthermore, the seasonal variance of moisture recycling and the fraction of precipitation that originates from evaporation from the same river basin is quantified. Using a quasi-isentropic moisture tracking scheme, evaporation from land surfaces in India is tracked through the atmosphere until precipitation brings it back to the land surface. This scheme is forced with ERA-Interim reanalysis data from 1990 to 2009. With the information about the atmospheric paths of water vapor, the distance between evaporation and precipitation location is determined. To get an approximation of the influence of land use on the atmospheric moisture budget, the atmospheric paths of water vapor from two bordering areas with different evaporative regimes are compared. Results show a strong annual cycle in the recycling ratio. For the Ganges basin, the recycling ranges from 5% during the winter months (November-March) to 60% during the June-July-August season. The comparison of two focus areas in the Ganges basin with a difference in March-August evaporation shows that during the premonsoon months (March-May), up to 70% of the evaporation difference between the two areas recycles within the Ganges basin. Analysis of the soil moisture nudging terms in ERA-Interim compared to independent irrigation data strongly suggest this evaporation difference can be attributed to large-scale irrigation. The importance of basin moisture recycling for precipitation shows an annual cycle as well. An annual average of 4.5% of Ganges precipitation originates from water evaporating in the Ganges basin. During the dry winter monsoon, any precipitation originates from sources outside the basin. During March-April-May and October-November, 10% of the precipitation originates from evaporation within the basin. During the summer monsoon season, the large influx of moisture from the Indian Ocean dominates the precipitation, and recycling is 5% of precipitation.

Tuinenburg, O. A.; Hutjes, R. W. A.; Kabat, P.

2012-01-01

67

DIVISION S-1—SOIL PHYSICS Modeling Soil Water Redistribution during Second-Stage Evaporation  

Microsoft Academic Search

practices such as irrigation scheduling (Lascano and Hatfield 1992; Chanzy and Bruckler, 1993; Bonsu, 1997). Calculating the dynamics of soil water content () near the surface Water evaporation from a soil surface can be divided and modeling soil water evaporation (Es) are critical for many agricul- into two stages: (i) the constant-rate stage in which Es tural management strategies. This

A. A. Suleiman; J. T. Ritchie

68

Isotope Fractionation of Water During Evaporation WithoutCondensation  

SciTech Connect

The microscopic events engendering liquid water evaporation have received much attention over the last century, but remain incompletely understood. We present measurements of isotope fractionation occurring during free molecular evaporation from liquid microjets and show that the isotope ratios of evaporating molecules exhibit dramatic differences from equilibrium vapor values, strong variations with the solution deuterium mole fraction, and a clear temperature dependence. These results indicate the existence of an energetic barrier to evaporation and that the evaporation coefficient of water is less than unity. These new insights into water evaporation promise to advance our understanding of the processes that control the formation and lifetime of clouds in the atmosphere.

Cappa, Christopher D.; Drisdell, Walter S.; Smith, Jared D.; Saykally, Richard J.; Cohen, Ronald C.

2005-10-19

69

THE ROLE OF AQUEOUS THIN FILM EVAPORATIVE COOLING ON RATES OF ELEMENTAL MERCURY AIR-WATER EXCHANGE UNDER TEMPERATURE DISEQUILIBRIUM CONDITIONS  

EPA Science Inventory

The technical conununity has only recently addressed the role of atmospheric temperature variations on rates of air-water vapor phase toxicant exchange. The technical literature has documented that: 1) day time rates of elemental mercury vapor phase air-water exchange can exceed ...

70

Oil shale process water evaporation. Final report.  

National Technical Information Service (NTIS)

The primary objectives of this research program were to study chemical, microclimatological, and interactive effects on the evaporation of low-quality oil shale process wastewaters to develop more applicable evaporation models and evaporation design crite...

V. R. Hasfurther T. Reeves

1990-01-01

71

Monthly Reservoir Evaporation Rates for Texas, 1940 Through 1965.  

National Technical Information Service (NTIS)

This revised report contains the gross and net monthly evaporation rates for the period 1940 through 1957 inclusive of all the existing evaporation and climatological stations for the entire state of Texas. It also includes a base State map showing applic...

J. W. Kane

1967-01-01

72

Increasing Water Supplies by Suppression of Reservoir Evaporation.  

National Technical Information Service (NTIS)

Water supplies in Southwestern reservoirs are seriously affected by evaporation. Chemical evaporation suppressants are only 35% to 40% efficient and are seriously affected by the wind. As an alternative, floating covers of solid or flexible materials offe...

F. R. Crow

1973-01-01

73

Impact of nitric acid on ice evaporation rates  

Microsoft Academic Search

Recent studies have suggested that nitric acid uptake by ice clouds may decrease ice evaporation rates and thereby prolong the cloud lifetimes. To test this suggestion, ice desorption rates were studied as a function of HNO3 partial pressure (10-6-10-5Torr), relative humidity (28-92%), and temperature (192-204 K) using optical interference of a helium neon laser. Ice evaporation rates in the presence

Matthew S. Warshawsky; Mark A. Zondlo; Margaret A. Tolbert

1999-01-01

74

Calculation of evaporation rates during the transition from energy-limiting to soil-limiting phases using albedo data  

Microsoft Academic Search

A method is presented that utilizes albedo measurements to partition the fraction of the soil surface area exhibiting energy-limiting (potential) evaporation and the fraction exhibiting soil-limiting evaporation to calculate actual evaporation rates during the transition phase (energy limiting to soil limiting). Since albedo is proportional to the surface water content, the change in albedo from day to day is indicative

R. D. Jackson; S. B. Idso; R. J. Reginato

1976-01-01

75

Evaporation Rate of Volatile Liquids. Final Report, Second Edition.  

National Technical Information Service (NTIS)

The research was designed to determine whether the evaporation rate of a volatile liquid could be adequately predicted from its common 'handbook' properties over a narrow range of environmental conditions. An experimental apparatus to measure the evaporat...

K. J. Caplan K. O. Braun

1989-01-01

76

What determines drying rates at the onset of diffusion controlled stage-2 evaporation from porous media?  

Microsoft Academic Search

A new model to estimate the evaporation rate at the onset of stage-2 evaporationBetter understanding of the evaporation from porous mediaAnalysis of liquid and vapor transport during evaporation from porous media

N. Shokri; D. Or

2011-01-01

77

Experimental study of flash evaporation of a water film  

Microsoft Academic Search

This experimental study of the flash evaporation phenomenon of a water film was carried out with an initial water height of 15 mm, superheats ranging from 1 to 35 K and initial temperatures from 30 to 75 °C. During a sudden pressure drop, temperature measurements of the water film allowed us to determine the water mass evaporated by this phenomenon

D. Saury; S. Harmand; M. Siroux

2002-01-01

78

Nonideal statistical rate theory formulation to predict evaporation rates from equations of state.  

PubMed

A method of including nonideal effects in the statistical rate theory (SRT) formulation is presented and a generic equation-of-state based SRT model was developed for predicting evaporation rates. Further, taking the Peng-Robinson equation of state as an example, vapor phase pressures at which particular evaporation rates are expected were calculated, and the predictions were found to be in excellent agreement with the experimental observations for water and octane. A high temperature range (near the critical region) where the previously existing ideal SRT model is expected to yield inaccurate results was identified and predictions (for ethane and butane) were instead made with the Peng-Robinson based SRT model to correct for fluid nonidealities at high temperatures and pressures. PMID:18954106

Kapoor, Atam; Elliott, Janet A W

2008-11-27

79

Impact of nitric acid on ice evaporation rates  

NASA Astrophysics Data System (ADS)

Recent studies have suggested that nitric acid uptake by ice clouds may decrease ice evaporation rates and thereby prolong the cloud lifetimes. To test this suggestion, ice desorption rates were studied as a function of HNO3 partial pressure (10-6-10-5 Torr), relative humidity (28-92%), and temperature (192-204 K) using optical interference of a helium neon laser. Ice evaporation rates in the presence of 1 × 10-6 Torr HNO3 were indistinguishable from those of pure ice. In contrast, ice evaporation in the presence of 8 × 10-6 Torr HNO3 resulted in lower evaporation rates by 33% relative to pure ice. Higher partial pressures of HNO3 result in a supercooled H2O/HNO3 liquid layer over ice, which may freeze to form a sealed NAT coating. This causes a lowering of the ice evaporation rate and prolongs the lifetime of ice. Ice exposed to lower partial pressures of HNO3 will not form a liquid layer and will thus evaporate at the same rate as pure ice.

Warshawsky, Matthew S.; Zondlo, Mark A.; Tolbert, Margaret A.

80

Soil-Water Evaporation Dynamics Determined From Soil Sensible Heat Transfer Measurements  

NASA Astrophysics Data System (ADS)

Soil-water evaporation is important in both the hydrologic cycle and the surface energy balance and for processes ranging from microbial ecology to global climate change. Yet, routine measurements are unable to capture rapidly shifting near-surface soil heat and water transfer processes involved in soil-water evaporation. Recent advancements in fine-scale measurement of soil thermal properties provide a new opportunity to observe heat transfer associated with soil-water evaporation in the upper centimeters of the vadose zone. The objective of this study was to determine the depth and location of the evaporation zone within soil using observations of sensible heat transfer. Three-needle heat-pulse sensors were used to monitor soil heat capacity, thermal conductivity, water content, and temperature below a bare soil surface in Central Iowa during natural wetting/drying cycles. Soil heat flux and changes in heat storage were calculated from these data to obtain a balance of sensible heat components. The residual from this balance (i.e., the net heat flux minus the change in heat storage) was attributed to latent heat from water evaporation, and thus, provided estimates of in situ water evaporation. As the soil dried following rainfall, results showed divergence in the soil sensible heat flux with depth. Divergence in the heat flux indicated the location of a heat sink associated with soil-water evaporation. Evaporation estimates from the sensible heat balance provided depth and time patterns consistent with observed soil-water depletion patterns. Evaporation occurred near the soil surface immediately after rainfall and the evaporation zone proceeded below 3 mm in the profile within 2-3 d of rainfall events. As the soil dried, the evaporation zone continued to penetrate deeper into the soil extending below 13 mm within 6 d after rainfall. Peak evaporation rates as high as 0.42 mm/h were observed at the 3-mm depth near midday, with evaporation declining by late afternoon. Evaporation occurred simultaneously at multiple soil depth increments, but with time lag between peak evaporation rates for the deeper depths. Daily heat-balance evaporation estimates compared well with microlysimeter evaporation estimates taken 3 or more d after rainfall providing root mean square error of 0.11 mm/d and r2 = 0.90. Implementation of fine-scale measurement techniques for the soil sensible heat balance provides a new opportunity to improve understanding of soil-water evaporation.

Heitman, J. L.; Horton, R.; Sauer, T. J.; Desutter, T. M.

2007-12-01

81

Evaporation rates of alkanes and alkanols from acoustically levitated drops  

Microsoft Academic Search

Evaporation constants of acoustically levitated drops from the homologue series of n-alkanes and 1-alkanols in ambient air have been evaluated by size and temperature measurements. The size of the pure liquid drops, within a diameter range of 0.1 to 2.5 mm, was monitored using a CCD camera, while temperature measurements were carried out by IR thermography. During drop evaporation, water

Rudolf Tuckermann; Sigurd Bauerecker; Bernd Neidhart

2002-01-01

82

Sensible heat observations reveal soil-water evaporation dynamics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil water evaporation is important at scales ranging from microbial ecology to large-scale climate. Yet, routine measurments are unable to capture rapidly shifting near-surface soil heat and water processes involved in soil-water evaporation. The objective of this study was to determine the depth a...

83

Investigating the Water Cycle: Using Plants to Study Evaporation  

NSDL National Science Digital Library

In this science activity, students investigate the water cycle by testing the water evaporated from leaves (transpiration) in a field experience. Students use elements of this information to track the water cycle through it's various stages.

84

Temporary skin substitutes and evaporative water loss.  

PubMed

The authors worked out a simple method, which enables an orientative evaluation of different skin substitutes as to their effectiveness in preventing gross evaporative water loss from decorticated dermis. The method is based on the loss of weight of decorticated dermis samples (covered by different materials) incubated in a thermostat for 1, 2, 3 and 4 hours at 37 degrees C. Following skin substitutes were tested: Lyofoam; Epigard; collagen foil; freeze dried amniotic membrane; freeze dried porcine xenografts; deep frozen porcine xenografts; and fresh porcine xenografts. Controls lost during 4 hours incubation at 37 degrees C 61.34% of the original weight (similarly as samples covered by synthetic skin substitutes or amniotic membrane). Samples covered by freeze dried xenografts lost only 33.07%, samples covered by deep frozen xenografts 13.20% and by fresh xenografts, 6.06%. PMID:377464

Moserová, J; B?hounková-Housková, E

1979-01-01

85

PROCESS WATER BUILDING, TRA605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), ...  

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

PROCESS WATER BUILDING, TRA-605. FLASH EVAPORATOR, CONDENSER (PROJECT FROM EVAPORATOR), AND STEAM EJECTOR (ALONG REAR WALL). INL NEGATIVE NO. 4377. M.H. Bartz, Photographer, 3/5/1952 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

86

Turbulent transition of thermocapillary flow induced by water evaporation  

NASA Astrophysics Data System (ADS)

Water has been examined for thermocapillary convection while maintained just outside the mouth of a stainless-steel, conical funnel where it evaporated at different but steady rates. Evaporation at a series of controlled rates was produced by reducing the pressure in the vapor-phase to different but constant values while maintaining the temperature of the water a few millimeters below the interface at 3.56±0.03 °C in each case. Since water has its maximum density at 4 °C , these conditions ensured there would be no buoyancy-driven convection. The measured temperature profile along the liquid-vapor interface was found to be approximately axisymmetric and parabolic with its minimum on the center line and maximum at the periphery. The thermocapillary flow rate was determined in two ways: (1) It was calculated from the interfacial temperature gradient measured along the interface. (2) The deflection of a 12.7-?m -diameter, cantilevered probe inserted into the flow was measured and the liquid velocity required to give that deflection determined. The values determined by the two methods agree reasonably. As the vapor-phase pressure was reduced, the thermocapillary flow rate increased until a limiting value was reached. When the pressure was reduced further, certain of the variable relations underwent a bifurcation and the power spectrum of the probe displacement indicated it was a periodic function with frequency locking. These results suggest that thermocapillary flow plays an important role in the energy transport near the interface of evaporating water. In particular, it appears that the subinterface, uniform-temperature layer, reported in earlier studies, results from the mixing produced by the thermocapillary flow. The Stefan boundary condition is often applied to determine the energy flux to an interface where phase change is occurring; however, when there is strong convective flow parallel to the interface, the normal Stefan condition does not give an adequate description of the energy transport.

Ward, C. A.; Duan, Fei

2004-05-01

87

Turbulent transition of thermocapillary flow induced by water evaporation.  

PubMed

Water has been examined for thermocapillary convection while maintained just outside the mouth of a stainless-steel, conical funnel where it evaporated at different but steady rates. Evaporation at a series of controlled rates was produced by reducing the pressure in the vapor-phase to different but constant values while maintaining the temperature of the water a few millimeters below the interface at 3.56+/-0.03 degrees C in each case. Since water has its maximum density at 4 degrees C, these conditions ensured there would be no buoyancy-driven convection. The measured temperature profile along the liquid-vapor interface was found to be approximately axisymmetric and parabolic with its minimum on the center line and maximum at the periphery. The thermocapillary flow rate was determined in two ways: (1) It was calculated from the interfacial temperature gradient measured along the interface. (2) The deflection of a 12.7-microm-diameter, cantilevered probe inserted into the flow was measured and the liquid velocity required to give that deflection determined. The values determined by the two methods agree reasonably. As the vapor-phase pressure was reduced, the thermocapillary flow rate increased until a limiting value was reached. When the pressure was reduced further, certain of the variable relations underwent a bifurcation and the power spectrum of the probe displacement indicated it was a periodic function with frequency locking. These results suggest that thermocapillary flow plays an important role in the energy transport near the interface of evaporating water. In particular, it appears that the subinterface, uniform-temperature layer, reported in earlier studies, results from the mixing produced by the thermocapillary flow. The Stefan boundary condition is often applied to determine the energy flux to an interface where phase change is occurring; however, when there is strong convective flow parallel to the interface, the normal Stefan condition does not give an adequate description of the energy transport. PMID:15244933

Ward, C A; Duan, Fei

2004-05-25

88

RATES OF EVAPORATION. Nuclear Reactor Containment Bimonthly Report No. 14  

Microsoft Academic Search

In a study of the maximum heat transfer rates for forced convective two-; phase flow, knowledge of the conditions under which the net evaporation rates ; from a liquid surface would sustain the heat fluxes in the range of burnout is ; desirable. The results of an analytical investigation in this area are presented. ; The theoretical expressions for the

Gavalas

1962-01-01

89

Evaporation from a shallow water table: Diurnal dynamics of water and heat at the surface of drying sand  

NASA Astrophysics Data System (ADS)

Accurate estimates of water losses by evaporation from shallow water tables are important for hydrological, agricultural, and climatic purposes. An experiment was conducted in a weighing lysimeter to characterize the diurnal dynamics of evaporation under natural conditions. Sampling revealed a completely dry surface sand layer after 5 days of evaporation. Its thickness was <1 cm early in the morning, increasing to reach 4-5 cm in the evening. This evidence points out fundamental limitations of the approaches that assume hydraulic connectivity from the water table up to the surface, as well as those that suppose monotonic drying when unsteady conditions prevail. The computed vapor phase diffusion rates from the apparent drying front based on Fick's law failed to reproduce the measured cumulative evaporation during the sampling day. We propose that two processes rule natural evaporation resulting from daily fluctuations of climatic variables: (i) evaporation of water, stored during nighttime due to redistribution and vapor condensation, directly into the atmosphere from the soil surface during the early morning hours, that could be simulated using a mass transfer approach and (ii) subsurface evaporation limited by Fickian diffusion, afterward. For the conditions prevailing during the sampling day, the amount of water stored at the vicinity of the soil surface was 0.3 mm and was depleted before 11:00. Combining evaporation from the surface before 11:00 and subsurface evaporation limited by Fickian diffusion after that time, the agreement between the estimated and measured cumulative evaporation was significantly improved.

Assouline, S.; Tyler, S. W.; Selker, J. S.; Lunati, I.; Higgins, C. W.; Parlange, M. B.

2013-07-01

90

Exploring Evaporation  

NSDL National Science Digital Library

Students learn what evaporation is and how various factors--time, heat, surface area, and wind--affect it. They also discover that water does not always evaporate at the same rate and saltwater leaves something behind when it evaporates. Finally, students a

Eichinger, John

2009-05-15

91

Water storage and evaporation as constituents of rainfall interception  

Microsoft Academic Search

Intercepted rainfall may be evaporated during or after the rain event. Intercepted rain is generally determined as the difference between rainfall measurements outside and inside the forest. Such measurements are often used to discriminate between water storage and evaporation during rain as well. Two well-accepted methods underestimate water storage by a factor two as compared to direct observations. The underestimation

Wim Klaassen; Fred Bosveld; E. de Water

1998-01-01

92

Evaporative water loss, relative water economy and evaporative partitioning of a heterothermic marsupial, the monito del monte (Dromiciops gliroides).  

PubMed

We examine here evaporative water loss, economy and partitioning at ambient temperatures from 14 to 33°C for the monito del monte (Dromiciops gliroides), a microbiotheriid marsupial found only in temperate rainforests of Chile. The monito's standard evaporative water loss (2.58 mg g(-1) h(-1) at 30°C) was typical for a marsupial of its body mass and phylogenetic position. Evaporative water loss was independent of air temperature below thermoneutrality, but enhanced evaporative water loss and hyperthermia were the primary thermal responses above the thermoneutral zone. Non-invasive partitioning of total evaporative water loss indicated that respiratory loss accounted for 59-77% of the total, with no change in respiratory loss with ambient temperature, but a small change in cutaneous loss below thermoneutrality and an increase in cutaneous loss in and above thermoneutrality. Relative water economy (metabolic water production/evaporative water loss) increased at low ambient temperatures, with a point of relative water economy of 15.4°C. Thermolability had little effect on relative water economy, but conferred substantial energy savings at low ambient temperatures. Torpor reduced total evaporative water loss to as little as 21% of normothermic values, but relative water economy during torpor was poor even at low ambient temperatures because of the relatively greater reduction in metabolic water production than in evaporative water loss. The poor water economy of the monito during torpor suggests that negative water balance may explain why hibernators periodically arouse to normothermia, to obtain water by drinking or via an improved water economy. PMID:22837452

Withers, Philip C; Cooper, Christine E; Nespolo, Roberto F

2012-08-15

93

Measurement of Evaporation Rates of Organic Liquids by Optical Interference  

Microsoft Academic Search

The He-Ne laser and the solid state laser pointer are inexpensive sources of collimated light which can be used in undergraduate laboratory experiments. In this article, the rate of evaporation is measured for several volatile organic liquids by optical interference. The laser light reflects and refracts at the air-surface interface; the latter beam then reflects at the lower liquid glass

Scott A. Riley; Nathan R. Franklin; Bobbie Oudinarath; Sally Wong; David Congalton; A. M. Nishimura

1997-01-01

94

Experimental Determination of Liquid Evaporation Rates in Superheated Fluidized Beds  

Microsoft Academic Search

Important applications of fast fluidized beds include reactors where liquid feed is sprayed into the co-current flow of solid particles and gas. When the gas and the solid particles are superheated relative to the saturation temperature of the liquid, the liquid drops evaporate at a rate governed by interfacial heat and mass transfer. This article describes an experimental method to

W. K. Gu; John C. Chen

1997-01-01

95

Measurement of spray droplet evaporation rate constant by laser diffraction  

Microsoft Academic Search

A technique for measuring the droplet evaporation rate constant for a spray is shown, and a novel laser diffraction technique is applied to the investigation of spray vaporizations. Local spatial size and distribution were measured in volume elements within a quasi two dimensional spray injected from the fan spray nozzle. The diffracted total light energy and its relative diffracted light

M. Nakayama; T. Arai

1985-01-01

96

Measuring Evaporation Rates of Methane Under Simulated Titan Conditions  

Microsoft Academic Search

It has been shown before that liquids exist on present-day Titan. In this work, Titan conditions are generated in our simulation chamber, and the evaporation rate of liquid methane is measured under surface temperatures of 90-94 K.

A. Luspay-Kuti; F. C. Wasiak; V. F. Chevrier; D. G. Blackburn; L. Roe

2011-01-01

97

Interpreting the H/D Isotope Fractionation of Liquid Water DuringEvaporation Without Condensation  

SciTech Connect

A theoretical model of liquid water evaporation has been developed to interpret results from a recent experimental investigation of isotope fractionation during free evaporation. It is established that the free evaporation isotope fractionation factors ({alpha}{sub evap}) are primarily influenced by the nature of the intermolecular interactions between water molecules, namely, the condensed phase hindered translational and librational frequencies at the surface. The dependence of {alpha}{sub evap} on the isotopic composition of the liquid can be understood in terms of small variations in these frequencies with isotopic composition. This result suggests that the explicit nature of the solvation environment directly influences evaporation rates from liquids. The sensitivity of the calculated evaporation coefficient for liquid water to both temperature and isotope composition is also explored.

Cappa, Christopher D.; Smith, Jared D.; Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

2007-03-15

98

Charge separation at evaporation and vapor growth of ice and water  

SciTech Connect

A mathematical model of the interface charging at evaporation and growth of ice and water phases from vapor is proposed. This model takes into account the competition between the two mechanisms of charge separation, one of which is based on protons and the other involves orientational defects. The first mechanism leads to the accumulation of a positive charge by ice and water during evaporation, while the second one provides negative charge accumulation. The protonic mechanism dominates at low velocities of the evaporation front with respect to the condensed phase material (lower than 10{sup -11}-10{sup -9} m/s). At high rates, the mechanism based on orientational defects is dominant. When vapor is condensed, and, correspondingly, the ice and water phases grow, the charge polarity is opposite to the polarity in the case of evaporation. The proposed model adequately describes the experimentally observed interface electric current and the signs of phase charges during evaporation and condensation.

Shavlov, A. V., E-mail: shavlov@ikz.ru [Russian Academy of Sciences, Earth Cryosphere Institute, Siberian Branch (Russian Federation)

2008-11-15

99

Priority of the Mn Deposition Rate in Reactive Evaporation Conditions  

NASA Astrophysics Data System (ADS)

Manganese (Mn) oxide films used in lithium secondary batteries were prepared using the reactive evaporation method. One of the problems of using this method is that the manganese evaporant in the crucible suffers oxidation in an oxygen atmosphere. This deteriorates the Mn deposition rate with increasing the deposition run. A separator was introduced in the bottom of the Mn crucible. It could successfully isolate Mn evaporant from incoming oxygen atoms. The film properties depend on the oxygen flow rate, Mn deposition rate, and substrate temperature. These three parameters correlate closely with each other. The importance of Mn deposition rate compared to the rest of the parameters was recognized. The Mn deposition rate is governed by two parameters. One is the source temperature, and the other is the aperture size of the separator. The Mn3O4 films with a hausmannite structure can be prepared under the conditions of Mn deposition rate of 3-10 Å/s, separator aperture size of 6 mm?, source temperature of 960°C, wall temperature of 900°C and oxygen flow rate of 5 sccm.

Isai, Masaaki; Ichikawa, Hiroshi; Shimada, Takeyoshi; Morimoto, Keiichiro; Fujiyasu, Hiroshi; Ito, Yasumitsu

2000-12-01

100

Tube-side fouling in water chiller-flooded evaporators  

Microsoft Academic Search

This article reports on a two-part research project which analyzed chiller water samples and measured the fouling thermal resistance of evaporator tubes. In ASHRAE Research project RP-560, the objective was to determine the seasonal fouling resistances using actual field quality water under conditions typical of those experienced in field-instilled, water chiller-flooded evaporators. The research was divided into two parts. In

S. I. Haider; R. L. Webb; A. K. Meitz

1993-01-01

101

Wetland versus open water evaporation: An analysis and literature review  

NASA Astrophysics Data System (ADS)

Is the total evaporation from a wetland surface (including: open water evaporation, plant transpiration and wet/dry soil evaporation) similar, lower, or higher than evaporation from an open water surface under the same climatic conditions? This question has been the subject of long debate; the literature does not show a consensus. In this paper we contribute to the discussion in two steps. First, we analyse the evaporation from a wetland with emergent vegetation (Ea) versus open water evaporation (Ew) by applying the Penman-Monteith equation to identical climate input data, but with different biophysical characteristics of each surface. Second, we assess the variability of measured Ea/Ew through a literature review of selected wetlands around the globe.We demonstrate that the ratio Ea/Ew is site-specific, and a function of the biophysical properties of the wetland surface, which can also undergo temporal variability depending on local hydro-climate conditions. Second, we demonstrate that the Penman-Monteith model provides a suitable basis to interpret Ea/Ew variations. This implies that the assumption of wetland evaporation to behave similar to open water bodies is not correct. This has significant implications for the total water consumption and water allocation to wetlands in river basin management.

Mohamed, Y. A.; Bastiaanssen, W. G. M.; Savenije, H. H. G.; van den Hurk, B. J. J. M.; Finlayson, C. M.

102

Calculation of Reactive-evaporation Rates of Chromia  

SciTech Connect

A methodology is developed to calculate Cr-evaporation rates from Cr2O3 with a flat planar geometry. Variables include temperature, total pressure, gas velocity, and gas composition. The methodology was applied to solid-oxide, fuel cell conditions for metallic interconnects and to advanced-steam turbines conditions. The high velocities and pressures of the advanced steam turbine led to evaporation predictions as high as 5.18 9 10-8 kg/m2/s of CrO2(OH)2(g) at 760 °C and 34.5 MPa. This is equivalent to 0.080 mm per year of solid Cr loss. Chromium evaporation is expected to be an important oxidation mechanism with the types of nickel-base alloys proposed for use above 650 °C in advanced-steam boilers and turbines. It is shown that laboratory experiments, with much lower steam velocities and usually much lower total pressure than found in advanced steam turbines, would best reproduce chromium-evaporation behavior with atmospheres that approach either O2 + H2O or air + H2O with 57% H2O.

Holcomb, G.R.

2008-04-01

103

Solvated Ion Evaporation from Charged Water Nanodroplets  

Microsoft Academic Search

The behavior of electrified droplets in an atmospheric environment and the mechanism of ion formation in electrospray ionization are the subject of continuing debate. Experimental evidence to decide between the various models of ion formation (e.g., ion evaporation, Coulomb explosion, and charge residue model) is not readily available and is especially scarce for nanometer-sized droplets. Even the morphology, the structure,

Vasiliy Znamenskiy; Ioan Marginean; Akos Vertes

2003-01-01

104

Physically modeling operative temperatures and evaporation rates in amphibians  

USGS Publications Warehouse

(1) We designed a physical model that simulates the thermal and evaporative properties of live Western toads (Bufo boreas). (2) In controlled tests, the model tracked the body temperature of live toads with an average error of 0.3??0.03??C (test range=4-30??C). (3) It estimated the evaporative water loss of live toads with an average error of 0.35-0.65 g/h, or about 14% (test range=0.7-9 g/h). (4) Data collected with this physical model should provide an effective way for biologists to better understand habitat selection in toads and other amphibians. ?? 2004 Elsevier Ltd. All rights reserved.

Bartelt, P. E.; Peterson, C. R.

2005-01-01

105

Evaporation measurements by eddy covariance from an urban tropical water reservoir  

NASA Astrophysics Data System (ADS)

One of the major problems in the management of water reservoirs is the accurate estimation of water loss by evaporation. This is particularly true for countries where the water supply relies on imported and recycled water, seawater desalination, and rainfall collected in reservoirs, such as Singapore. Within this context, an eddy covariance system was deployed on the shore of an urban water body in Singapore (Bedok reservoir) with sufficient fetch to measure the upwind evaporation during a period of two weeks. This was likely the first such study for a small urban tropical water catchment. Evaporation was found to follow a clear diurnal pattern, ranging from 0.03 mm h-1 during nighttime to an early afternoon peak of 0.25 mm h-1. These values are similar to the summertime evaporation rates reported for larger lakes in subtropical or mid-latitude locations. The evaporation shows a strong correlation with atmospheric turbulence u* (friction velocity) which is related to wind speed. However, the heat stored in the water appears to be the main parameter driving the evaporation from the reservoir because of the relatively calm winds (< 2.5 m s-1) observed during most of the study. The surface water temperature was consistently (between 2 - 3.5 degC) warmer than air temperature throughout the diurnal course. Much of the net radiation received during daytime is channeled into heating the water which results in the higher water temperatures. The high humidity (> 65%) during the study appears, on the other hand, to work to reduce evaporation. These results are preliminary and a longer observation period is needed to be able to carry out a more thorough analysis. The results, however, are useful to test simple predictive evaporation models based on similarity theory and which require only basic meteorological input data.

Velasco, E.; Roth, M.

2010-12-01

106

Porous multiphase approach for baking process – Explicit formulation of evaporation rate  

Microsoft Academic Search

A multiphase model for simultaneous heat and mass transfer in porous medium was developed to simulate the baking process of a bread product. The model was based on Fourier’s law for conductive heat transfer and Darcy’s and Fick’s laws for mass transfer of liquid (water) and gas (water vapour and CO2) phases. Explicit formulation was adopted for the evaporation rate

A. Ousegui; C. Moresoli; M. Dostie; B. Marcos

2010-01-01

107

On laboratory simulation and the temperature dependence of the evaporation rate of brine on Mars  

Microsoft Academic Search

We have determined the evaporation rate of brine under simulated martian conditions at temperatures from 0°C to -26.0°C as part of our efforts to better understand the stability of water on Mars. Correcting for the effect of water build-up in the atmosphere and the lower gravity on Mars relative to Earth we observed a factor of almost 30 decrease in

Derek W. G. Sears; Julie D. Chittenden

2005-01-01

108

On laboratory simulation and the temperature dependence of the evaporation rate of brine on Mars  

Microsoft Academic Search

We have determined the evaporation rate of brine under simulated martian conditions at temperatures from 0°C to ?26.0°C as part of our efforts to better understand the stability of water on Mars. Correcting for the effect of water build-up in the atmosphere and the lower gravity on Mars relative to Earth we observed a factor of almost 30 decrease in

Derek W. G. Sears; Julie D. Chittenden

2005-01-01

109

EVAPORATIVE COOLING AND WATER BALANCE DURING FLIGHT IN BIRDS  

Microsoft Academic Search

SUMMARY The rate of evaporative cooling was calculated from the rate of mass loss in starlings (Sturnus vulgaris) during 90 min flights in a wind-tunnel. Evapo- rative heat loss ranged from 5 % of the metabolic rate at — 5 °C to 19% of the metabolic rate at 29 °C. Radiation and convection accounted for the balance of the heat

JOSE R. TORRE-BUENO

110

Tillage effects on soil water redistribution and bare soil evaporation throughout a season  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tillage-induced changes in soil properties are difficult to predict, yet can influence how water is redistributed within the profile after precipitation and subsequent evaporation rates. We evaluated the effects of sweep tillage (ST) on near surface soil water dynamics as compared with an untilled (...

111

Selective Adsorption of Ions to Aqueous Interfaces and its Effects on Evaporation Rates  

NASA Astrophysics Data System (ADS)

By exploiting the strong UV charge-transfer-to-solvent (CTTS) resonances of selected anions in aqueous electrolytes, their interfacial adsorption properties are measured by UV-SHG spectroscopy. Temperature and concentration dependences are determined, with the goal of establishing a molecular description of selective ion adsorption. A study of prototypical chaotrope thiocyanate reveals that its strong adsorption is driven by enthalpic forces and impeded by entropy. A study of nitrite indicates even stronger adsorption as an ion pair with sodium. Evaporation rates are measured by combining liquid microjet technology and Raman thermometry. The relationship between surface propensities of ions and evaporation rates is investigated. A detailed molecular mechanism for aqueous evaporation is sought. W. S. Drisdell, R. J. Saykally, R. C. Cohen Effect of Surface Active Ions on the Rate of Water Evaporation, J. Phys. Chem. C 114, 11880-11885 (2010). D.E. Otten, R. Onorato, R. Michaels, J. Goodknight, R. J. Saykally "Strong Surface Adsorption of Aqueous Sodium Nitrite as an Ion Pair," Chem. Phys. Lett. 519-520, 45-48 (2012). D.E. Otten, P. Shaffer, P. Geissler, R.J. Saykally "Elucidating the Mechanism of Selective Ion Adsorption to the Liguid Water Surface," PNAS 109 (3), 701-705 (2012).

Saykally, Richard J.

2012-06-01

112

Influence of evaporation space geometry on rate of distillation in high-vacuum evaporator  

Microsoft Academic Search

The problem of calculation of a necessary evaporation surface area in a high-vacuum distillation apparatus with complicated geometry has not been fully resolved yet. Surface evaporation ranges (molecular distillation, the intermediate range, equilibrium distillation), in which different conditions of collisions between vapor particles exist, and their influences on effective evaporation still remain to be taken into account. An example of

Zdzis?aw Kawala; Pawe? Dakiniewicz

2002-01-01

113

Large Eddy Simulation investigation of evaporation from open water bodies  

Microsoft Academic Search

In regional hydrological systems, open water bodies such as lakes or wetlands are important components of the landscape. Atmospheric flows above such systems can rarely be approximated as stationary and homogeneous. Thus, the quantification of their evaporation is a challenge. In this work we use Large Eddy Simulations to explore the turbulence statistics of temperature and water vapor that are

N. Vercauteren; M. Froidevaux; C. Higgins; E. Bou-Zeid; M. B. Parlange

2010-01-01

114

Evaporative chemical evolution of natural waters at Yucca Mountain, Nevada  

Microsoft Academic Search

The authors report results from experiments on the evaporative chemical evolution of the two major types of natural waters present at Yucca Mountain, Nevada. The first is represented by J13 well water, a dilute Na–HCO3–CO3 water similar to saturated horizons in volcanic tuffs across the western United States. The second is represented by Ca–C1–SO4-rich pore water that has a higher

N. D Rosenberg; G. E Gdowski; K. G Knauss

2001-01-01

115

Numerical simulation of water evaporation inside vertical circular tubes  

NASA Astrophysics Data System (ADS)

In this paper the results of simplified numerical analysis of water evaporation in vertical circular tubes are presented. The heat transfer in fluid domain (water or wet steam) and solid domain (tube wall) is analyzed. For the fluid domain the temperature field is calculated solving energy equation using the Control Volume Method and for the solid domain using the Finite Element Method. The heat transfer between fluid and solid domains is conjugated using the value of heat transfer coefficient from evaporating liquid to the tube wall. It is determined using the analytical Steiner-Taborek correlation. The pressure changes in fluid are computed using Friedel model.

Oc?o?, Pawe?; Nowak, Marzena; Majewski, Karol

2013-10-01

116

Evaporation rates of pure hydrocarbon liquids under the influences of natural convection and diffusion  

Microsoft Academic Search

Evaporation of liquid hydrocarbons was studied in order to better understand the relative influences of diffusion and buoyancy-induced convection of the vapors on the evaporation rate. Evaporation rates were measured using a simple gravimetric technique and the behavior of the vapor layer that quickly forms above the film was observed using schlieren imaging. Even for conditions for which the influence

Peter L. Kelly-Zion; Christopher J. Pursell; Ryan S. Booth; Alec N. VanTilburg

2009-01-01

117

Determination of Evaporation Rate and Vapor Pressure of Organic Monomers Used for Vapor Deposition Polymerization  

Microsoft Academic Search

Thermogravimetry (TG) and the Langmuir equation have been employed for the determination of the temperature dependence of the evaporation rate and saturated pressure of monomers used in vapor deposition polymerization (VDP). The measuring process utilizes the evaporation of monomers in vacuum. The ranges of the evaporation rate and saturated pressure of monomers as determined by the TG technique are from

Yoshikazu Takahashi; Kanenori Matsuzaki; Masayuki Iijima; Eiichi Fukada; Sonoko Tsukahara; Yukimasa Murakami; Akikazu Maesono

1993-01-01

118

Evaporator analysis for application to water-source and ice-maker heat pumps  

SciTech Connect

Water-source and ice-maker heat pumps share many characteristics. However, each presents different technical difficulties that have prevented them from being used more widely. In a water-source heat pump a very important consideration is to reduce water consumption, while in an ice-maker heat pump a major concern is to reduce the number of deicing cycles while keeping a high performance. Previous research by this author has indicated that the use of the flow reversal method (reversing periodically the water flow direction in the evaporator) has the effect of partly deicing the evaporator, reducing pressure drop and enhancing heat transfer. This thesis shows the development and application of analytical and numerical models to study the effect of different evaporator parameters on heat pump efficiency, as well as the possible advantages of using the flow reversal method in a water-source or ice-maker heat pump. The conclusion reached from these studies is that periodic water flow reversals inside an evaporator with freezing help improve the performance of a heat pump system in two different ways. First, periodic water flow direction reversals serve to enhance heat transfer in the evaporator. Second, reversing the water flow direction also delays ice blockage in the evaporator, or totally prevents blockage from happening. Delaying ice blockage represents a substantial improvement for ice-maker heat pumps, since these may then operate for a longer time without deicing. Preventing ice blockage represents a substantial improvement for water-source heat pumps, since these may then operate at lower water flow rates.

Aceves-Saborio, S.M.

1989-01-01

119

49. LOOKING NORTH AT EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS, ...  

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

49. LOOKING NORTH AT EVAPORATIVE WASTE WATER TREATMENT COOLING TOWERS, WITH BLOW ENGINE HOUSE No. 3 ON RIGHT, AND FILTER CAKE HOUSE IN FOREGROUND. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

120

Changes in evaporation rate and vapor pressure of gasoline with progress of evaporation  

Microsoft Academic Search

The evaporation properties of motor gasoline are expected to change markedly with the progress of evaporation because gasoline is a multi-component fuel. The aim of this paper was to develop a prediction model of the amount of vapor generated from gasoline spill. The risks associated with gasoline spills can be accurately evaluated by the models. Degraded samples of regular gasoline

Katsuhiro Okamoto; Norimichi Watanabe; Yasuaki Hagimoto; Koji Miwa; Hideo Ohtani

2009-01-01

121

Large Eddy Simulation investigation of evaporation from open water bodies  

NASA Astrophysics Data System (ADS)

In regional hydrological systems, open water bodies such as lakes or wetlands are important components of the landscape. Atmospheric flows above such systems can rarely be approximated as stationary and homogeneous. Thus, the quantification of their evaporation is a challenge. In this work we use Large Eddy Simulations to explore the turbulence statistics of temperature and water vapor that are relevant to evaporation. Specifically, we investigate the effect of dry air entrainment above a water body on the transport characteristics of temperature and water vapor. The vertical transport efficiencies of the two scalars are compared for a simulation of an infinite lake, the transition between a wet and a dry surface with varying temperatures. The spectral similarity of the scalars is analyzed in the different examples. The analysis focuses on how the relative transport efficiencies RwT/Rwq are perturbed from unity with increased advection or the atmospheric stability. Results are compared with an experimental study performed over three water bodies of different sizes and climates by (Assouline, Tyler et al. 2008). Assouline, S., S. W. Tyler, et al. (2008). "Evaporation from three water bodies of different sizes and climates: Measurements and scaling analysis." Advances in Water Resources 31(1): 160-172.

Vercauteren, N.; Froidevaux, M.; Higgins, C.; Bou-Zeid, E.; Parlange, M. B.

2010-09-01

122

Estimates of Evaporation From Terrestrial Surface Water Bodies Using the Global Lakes and Wetlands Database  

NASA Astrophysics Data System (ADS)

Land surface modeling has led to significant advances in the understanding the role of the terrestrial hydrologic cycle in the Earth system. However, the representation of land surface of in these modeling approaches suffers from drawbacks such as lack of representation of terrestrial surface water bodies. These water bodies play an important role in the hydrological and biogeochemical cycles and thus should be included in the computation of the hydrologic budget. To emphasize the contribution of surface water bodies towards the total terrestrial evaporative flux, we present global estimates of monthly evaporation rates from lakes, rivers and reservoirs. The identification of lakes, river and reservoirs follows from the Global Lakes and Wetlands Database (Lehner and Doll [2004]). Evaporation is estimated using the Penman formulation, using observed global net radiation and temperature data from Langley Surface Radiation Budget data. We compare our estimates with those from other studies for different hydrologic regions of the world (such as the Mississippi and the Congo basins).

Ortiz, V.; Goteti, G.; Famiglietti, J.

2005-12-01

123

Water–zeolite adsorption heat pump combined with single effect evaporation desalination process  

Microsoft Academic Search

The single effect evaporation desalination process combined with adsorption heat pump (ADVC) is modeled analyzed as a function of the system design and operating parameters. The analysis gives variations in the thermal performance ratio, the specific heat transfer area, and the specific flow rate of cooling water. The performance evaluation is made as a function of the brine boiling temperature,

Ahmad Al-Ansari; Hisham Ettouney; Hisham El-Dessouky

2001-01-01

124

Cold-hardiness and evaporative water loss in hatchling turtles.  

PubMed

North American turtles hatch in late summer and spend their first winter either on land or underwater. Adaptations for terrestrial overwintering of hatchlings in northern regions, where winter thermal and hydric regimes are harsh, have not been systematically investigated in many species. We measured intrinsic supercooling capacity, resistance to inoculative freezing, and desiccation resistance in hatchlings of terrestrial and aquatic turtles collected from northern (Terrapene ornata, Chrysemys picta bellii, Kinosternon flavescens, Chelydra serpentina) and southern (Chrysemys picta dorsalis, Trachemys scripta, Sternotherus odoratus, Sternotherus carinatus) locales. Supercooling capacity was estimated from the crystallization temperature of turtles cooled in the absence of external ice nuclei. Mean values ranged from -8.1 degrees to -15.5 degrees C and tended to be lower in terrestrial hibernators. Inoculation resistance was estimated from the crystallization temperature of turtles cooled in a matrix of frozen soil. These values (range of means: -0.8 degrees to -13.6 degrees C) also tended to be lower in the terrestrial hibernators, especially C. picta bellii. Mean rates of evaporative water loss varied markedly among the species (0.9-11.4 mg g(-1) d(-1)) and were lowest in the terrestrial hibernators. Most species tolerated the loss of a modest amount of body water, although half of the sample of S. carinatus died from desiccation. In general, turtles did not regain lost body water from wet soil, and immersion in free water was required for rehydration. Therefore, desiccation resistance may be an important adaptation to terrestrial hibernation. Resistances to inoculative freezing and desiccation were directly correlated, perhaps because they are governed by the same morphological characteristics. PMID:11436135

Costanzo, J P; Litzgus, J D; Iverson, J B; Lee, R E

125

Benefits of evaporating FGD purge water  

SciTech Connect

In the US and the European Union, scrubbers are installed on all new coal-fired power plants because their technology is considered the best available for removing SO{sub 2}. A zero liquid discharge (ZLD) system is the best technology for treating wet scrubber wastewate. With the future promising stricter limits on power plants' water use, ZLD systems that concentrate scrubber purge streams are sure to become as common as ZLD cooling tower blowdonw systems. 7 figs.

Shaw, W.A. [HPD, Plainfield, IL (United States)

2008-03-15

126

Influence of Soil Water Stress on Evaporation, Root Absorption, and Internal Water Status of Cotton 1  

PubMed Central

Diurnal variations in leaf water potential, diffusion resistance, relative water content, stem diameter, leaf temperature, and energy balance components were measured in cotton (Gossypium hirsutum L. var. Lankart 57) during drought stress under field conditions. A plot of leaf water potential against either relative water content or stem diameter during the 24-hour period yielded a closed hysteresis loop. The relation between cell hydration and evaporation is discussed. Despite low soil water potential in the main root zone, significant plant evaporation rates were maintained. Root absorption rates as a function of soil depth were calculated from water content profiles measured with a neutron probe. The maximal root absorption rate of 3.5 × 10?3 day?1 occurred at the 75-centimeter depth, well below the main root zone. Stomatal resistance of individual leaves during the daylight hours remained nearly constant at 2.5 seconds centimeter?1 even though leaf water potentials approached ?30 bars. A growth chamber study indicated stomatal closure occurred at potentials near ?16 bars. Possible implications of high soil water stress in relation to stomatal function and growth are discussed. Based on an energy balance method, the actual to potential plant evapotranspiration ratio was 0.43 for the 24-hour period, indicating partial stomatal closure. A surface resistance, rs, of 4.0 seconds centimeter?1 was calculated for the incomplete canopy with the use of the energy balance data. Alternatively, a canopy resistance of 1.3 seconds centimeter?1 was attained from a relationship between leaf area and stomatal resistance of individual leaves. If the soil resistance was assumed to be very large and the canopy resistance was weighted for the fractional ground cover of the crop, the calculated surface resistance was 4.3 seconds centimeter?1. Under these conditions, the two independent estimates of rs were in essential agreement.

Jordan, Wayne R.; Ritchie, Joe T.

1971-01-01

127

The Economic Impact of Water Evaporation Losses from Water Reservoirs in the Segura Basin, SE Spain  

Microsoft Academic Search

In this paper we assess the economic impact of evaporation losses from great dams (GDs) and on-farm agricultural water reservoirs\\u000a (AWRs) in the semi-arid Segura River basin, SE Spain. Evaporation losses from water reservoirs reduce the high water use efficiency\\u000a reached in agriculture by means of other techniques such as well-built water pipes or drip irrigation and have a substantial

David Martínez-Granados; José Francisco Maestre-Valero; Javier Calatrava; Victoriano Martínez-Alvarez

128

Evaporation Correction Methods for Microwave Retrievals of Surface Precipitation Rate  

Microsoft Academic Search

Active and passive microwave remote sensing esti- mates of surface precipitation based on signals from hydrometeors aloft require correction for evaporated precipitation that would otherwise reach the ground. This paper develops and compares two near-surface evaporation correction methods using two years of data from 509 globally distributed rain gauges and three passive millimeter-wave Advanced Microwave Sounding Units (AMSUs) aboard National

Chinnawat Surussavadee; David H. Staelin

2011-01-01

129

Effect of Aquasorb and Organic Compost Amendments on Soil Water Retention and Evaporation with Different Evaporation Potentials and Soil Textures  

Microsoft Academic Search

Aquasorb PR3005A, a hydrophilic polymer (a salt copolymer polyacrylamide), and garden waste compost were added to a loamy sand and a loam soil in pots to assess their impact upon soil physical properties at two different evaporation potentials. Compost was mulched and incorporated, the Aquasorb was incorporated, and their effect on temperature and amelioration of soil water content and evaporation

M. Taban; S. A. R. Movahedi Naeini

2006-01-01

130

Evaporation of sessile water droplets: Universal behaviour in presence of contact angle hysteresis  

Microsoft Academic Search

A theory is presented, which describes the diffusion limited evaporation of sessile water droplets in presence of contact angle hysteresis. Theory describes two stages of evaporation process: (I) evaporation with a constant radius of the droplet base; and (II) evaporation with a constant contact angle. During stage (I) the contact angles decreases from static advancing contact angle to static receding

S. Semenov; V. M. Starov; R. G. Rubio; H. Agogo; M. G. Velarde

131

Oxygen consumption and evaporative water loss in infants with congenital heart disease  

Microsoft Academic Search

The relation between environmental temperature, heat production, oxygen consumption, and evaporative water loss was studied in 67 infants with congenital heart disease. The majority of the cyanosed infants had a low minimum oxygen consumption, a low evaporative water loss, and a diminished metabolic response to cold stress. Minimum oxygen consumption and evaporative water loss rose in 6 of these infants

D L Kennaird

1976-01-01

132

Numerical Evaluation of Heat Pulse Technology for Estimation of Evaporation Rates from a Subsurface Drying Front  

Microsoft Academic Search

Soil water evaporation plays a crucial role for both the soil surface energy balance and the hydrologic cycle. Recently introduced heat pulse probes (HPP) allow in-situ measurements of subsurface soil water evaporation. The sensible heat component is calculated from soil heat flux densities measured at two depths and the change in sensible heat storage between these depths is measured by

M. Sakai; S. B. Jones; M. Tuller

2009-01-01

133

Analysis of condensation and evaporation of ammonia/water mixtures in matrix heat-exchangers  

SciTech Connect

A theoretical analysis is carried out for the condensation and evaporation of water/ammonia mixtures in matrix heat-exchangers. A set of equations is formulated and a calculation algorithm is developed to predict the local rate of heat and mass transfer for binary-component systems. A thermodynamic property model is developed for ammonia/water mixtures on the basis of the Peng-Robinson equation for state. The two-phase flow heat-transfer coefficient for matrix heat-exchangers is calculated by using the analytical method developed in a previous study. The experimental data are analyzed to determine the effects of small amounts of water in ammonia on the rate of evaporation. The role of diffusion in simultaneous heat and mass transfer associated with condensation and evaporation processes are analyzed by comparing the results from three limiting cases, which include equilibrium conditions, and liquid-phase diffusion- resistance of finite and infinite values. The results show that the vapor-phase mass-transfer resistance is the controlling mechanism for condensation, and the liquid-phase mass-transfer resistance is the controlling mechanism for evaporation. 23 refs., 9 figs., 2 tabs.

Panchal, C.B.; Arman, B.

1991-01-01

134

Analysis of condensation and evaporation of ammonia/water mixtures in matrix heat-exchangers  

NASA Astrophysics Data System (ADS)

A theoretical analysis is carried out for the condensation and evaporation of water/ammonia mixtures in matrix heat-exchangers. A set of equations is formulated and a calculation algorithm is developed to predict the local rate of heat and mass transfer for binary-component systems. A thermodynamic property model is developed for ammonia/water mixtures on the basis of the Peng-Robinson equation of state. The two-phase flow heat-transfer coefficient for matrix heat-exchangers is calculated by using the analytical method developed in a previous study. The experimental data are analyzed to determine the effects of small amounts of water in ammonia on the rate of evaporation. The role of diffusion in simultaneous heat and mass transfer associated with condensation and evaporation processes are analyzed by comparing the results from three limiting cases, which include equilibrium conditions, and liquid-phase diffusion- resistance of finite and infinite values. The results show that the vapor-phase mass-transfer resistance is the controlling mechanism for condensation, and the liquid-phase mass-transfer resistance is the controlling mechanism for evaporation.

Panchal, C. B.; Arman, B.

135

Influence of changes in atmospheric pressure on evaporation rates of low-loss helium cryostats  

Microsoft Academic Search

Experimental equipment for pressure control and evaporation rate measurement of a low-loss helium cryostat is described. The dependence of the helium gas outflow on the linearly varying pressure is presented for an NMR cryostat. The variations in measured helium evaporation rate were significantly high during experiments simulating usual atmospheric pressure changes. The measured quantities are compared to those evaluated by

P. Hanzelka; V. Musilová

1995-01-01

136

Evaporation Rate and Lifetimes of Clouds and Sprays in Air—The Cellular Model  

Microsoft Academic Search

A simple, yet effective, mathematical model based on the cellular method is proposed for the study of the evaporation rate of liquid droplets in assemblages in air. It has been found that the modified cellular model is adequate for the determination of the rate of evaporation, the saturation point, and the lifetime of a monodisperse system of droplets. All characteristic

Joseph T. Zung

1967-01-01

137

Coupling effect between thermal and dynamic factors on water surface evaporation and in-situ observation  

Microsoft Academic Search

Water surface evaporation is an important indicator of atmospheric circulation and hydrological cycle. This paper, after selecting representative alluvial plain in north of Haihe River Basin as the experimental point, designs in-situ observation experiment to explore the influence of wind speed on water surface evaporation and puts forward the coupling effect between thermal and air dynamic factors on evaporation, which

Xuerui Gao; Dayong Qin; Jiahong Liu; Chuiyu Lu

2011-01-01

138

Numerical evaluation of subsurface soil water evaporation derived from sensible heat balance  

Microsoft Academic Search

A recently introduced measurement approach allows in situ determination of subsurface soil water evaporation by means of heat-pulse probes (HPP). The latent heat component of subsurface evaporation is estimated from the residual of the sensible heat balance. This heat balance method requires measurement of vertical soil temperature and estimates of thermal properties for soil water evaporation determination. Our objective was

Masaru Sakai; Scott B. Jones; Markus Tuller

2011-01-01

139

Water loss through evaporation from water surfaces of lakes and reservoirs in Turkey  

Microsoft Academic Search

The objective of this study2 was to estimate the amount of evaporative loss from fresh water lake and reservoir surfaces in Turkey and to compare it with supplied water in Turkey. In this study 129 lakes and 223 reservoirs were subjected to evaporation estimates. The total surface area was 3213.97 km2 and 4026.16 km2 for the lakes and the reservoirs,

Ferhat Gökbulak; Süleyman Özhan

2006-01-01

140

Evaporation from porous media in the presence of a water table  

Microsoft Academic Search

Improved understanding of soil evaporation in presence of a water table is important in many hydrological processes such as analysis of water and energy balance at land surface, and soil salinization. During evaporation, liquid water is transported from water table toward the surface by capillary forces opposed by the downward gravity and viscous forces. In presence of a shallow water

N. Shokri; G. Salvucci

2010-01-01

141

The effect of dioctyl phthalate films on the ammonium nitrate aerosol evaporation rate  

Microsoft Academic Search

The evaporation of submicrometer ammonium nitrate (NH4NO3) aerosol coated with an organic film was measured in order to determine the effect of the film on mass transfer rate and equilibration time of the semi-volatile inorganic. Ammonium nitrate (NH4NO3) particles 100–200nm in diameter were coated with dioctyl phthalate (DOP) and allowed to evaporate in a constant temperature laminar flow reactor. Evaporation

Celia N. Cruz; Konstandinos G. Dassios; Spyros N. Pandis

2000-01-01

142

Al/Si Metallization by Rate Controlled Dual EB-Gun Evaporation.  

National Technical Information Service (NTIS)

An industrial process for aluminium-silicon metallization using two rate controlled electron beam evaporators will be described. The two sources are operated simultaneously. The silicon source rate control is achieved by the direct measurement of the depo...

F. Hegner A. Feuerstein

1985-01-01

143

Experimental determination of fuel evaporation rates using IR-Thermography  

Microsoft Academic Search

The scope of the present work is to experimentally investigate the heat and mass transfer phenomena occurring in the case of pure liquid as well as FAME-diesel fuel mixture droplets evaporating in a constant temperature and constant air velocity environment. Experiments have been performed to record the time evolution of droplet diameter and surface temperature. An ultrasonic droplet acoustic levitator

M. Founti; D. Kolaitis; G. Zannis; O. Kastner; D. Trimis

144

Simulation of lake ice and its effect on the late-Pleistocene evaporation rate of Lake Lahontan  

USGS Publications Warehouse

A model of lake ice was coupled with a model of lake temperature and evaporation to assess the possible effect of ice cover on the late-Pleistocene evaporation rate of Lake Lahontan. The simulations were done using a data set based on proxy temperature indicators and features of the simulated late-Pleistocene atmospheric circulation over western North America. When a data set based on a mean-annual air temperature of 3?? C (7?? C colder than present) and reduced solar radiation from jet-stream induced cloud cover was used as input to the model, ice cover lasting ??? 4 months was simulated. Simulated evaporation rates (490-527 mm a-1) were ??? 60% lower than the present-day evaporation rate (1300 mm a-1) of Pyramid Lake. With this reduced rate of evaporation, water inputs similar to the 1983 historical maxima that occurred in the Lahontan basin would have been sufficient to maintain the 13.5 ka BP high stand of Lake Lahontan. ?? 1991 Springer-Verlag.

Hostetler, S. W.

1991-01-01

145

Respiratory evaporative water loss during hovering and forward flight in hummingbirds.  

PubMed

Hummingbirds represent an end point for small body size and water flux in vertebrates. We explored the role evaporative water loss (EWL) plays in management of their large water pool and its use in dissipating metabolic heat. We measured respiratory evaporative water loss (REWL) in hovering hummingbirds in the field (6 species) and over a range of speeds in a wind tunnel (1 species) using an open-circuit mask respirometry system. Hovering REWL during the active period was positively correlated with operative temperature (T(e)) likely due to some combination of an increase in the vapor-pressure deficit, increase in lung ventilation rate, and reduced importance of dry heat transfer at higher T(e). In rufous hummingbirds (Selasphorus rufus; 3.3g) REWL during forward flight at 6 and 10 m/s was less than half the value for hovering. The proportion of total dissipated heat (TDH) accounted for by REWL during hovering at T(e)> 40°C was <40% in most species. During forward flight in S. rufus the proportion of TDH accounted for by REWL was ~35% less than for hovering. REWL in hummingbirds is a relatively small component of the water budget compared with other bird species (<20%) so cutaneous evaporative water loss and dry heat transfer must contribute significantly to thermal balance in hummingbirds. PMID:22123217

Powers, Donald R; Getsinger, Philip W; Tobalske, Bret W; Wethington, Susan M; Powers, Sean D; Warrick, Douglas R

2011-11-21

146

Development of an evaporation-optimized and water-permeable pavement  

Microsoft Academic Search

During recent decades, urban areas have been threatened more frequently by flood events. Furthermore, the potential for damage from these events has increased on average. The construction of houses, streets and parking lots has caused this trend by sealing the ground surface, i.e. these water-impermeable areas reduce the natural infiltration and evaporation-rates, and in some cases it is even completely

P. Starke; P. Göbel; W. G. Coldewey

2009-01-01

147

Drying front and water content dynamics during evaporation from sand delineated by neutron radiography  

Microsoft Academic Search

Evaporative drying of porous media is jointly controlled by external (atmospheric) conditions and by media internal transport properties. Effects of different atmospheric potential evaporative demand on observed drying rates were studied in a series of laboratory experiments using sand-filled Hele-Shaw cells. We examined two potential evaporation rates of about 8 and 40 mm per day. The evolution and geometry of

N. Shokri; P. Lehmann; P. Vontobel; D. Or

2008-01-01

148

Dew-point hygrometry system for measurement of evaporative water loss in infants.  

PubMed

Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0 degree C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of approximately 0.02 mgH2O.cm-2.min-1 for normothermic baseline conditions and values up to 0.4 mgH2O.cm-2. min-1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss. PMID:9074995

Ariagno, R L; Glotzbach, S F; Baldwin, R B; Rector, D M; Bowley, S M; Moffat, R J

1997-03-01

149

Lumped modeling of solar-evaporative ponds charged from the water of the Dead Sea  

Microsoft Academic Search

Solar evaporators are widely used in salt mining from seawaters or saline waters. The potash industry in Jordan and other countries utilized solar energy in the evaporation process to concentrate seawater where salt starts to deposit. In this work, the thermal performance of such evaporators was analyzed and modeled on lumped basis. The developed model indicates that the efficiency of

A. Tamimi; K. Rawajfeh

2007-01-01

150

PHYSICAL EVALUATION OF EFFECTIVE EVAPORATIVE DEMAND WITH REFERENCE TO PLANT WATER RELATIONS  

Microsoft Academic Search

KITANO M., HAMAKOGA M. and EGUCHI H. Physical evaluation of effective evaporative demand with reference to plant water relations. BIOTRONICS 19, 109-119, 1990. Evaporative demand on a transpiring leaf was evaluated by en­ vironmental factors of radiation, ambient air temperature, humidity and wind velocity. Under different environmental conditions, a constant linear relation­ ship was found between the evaluated evaporative demand

M. KITANO; M. HAMAKOGA; H. EGUCHI

151

Evolution of surface area-to-volume ratio for a water meniscus evaporating between contacting silica spheres  

Microsoft Academic Search

An experimental investigation was performed under isothermal conditions to quantify the rate of evaporation of water from a receding pendular meniscus connecting two silica spheres. Optically based measurements were used to determine the relevant meniscus dimensions, and the meniscus was modeled using a toroidal approximation. The rate of change of meniscus surface area and volume was then predicted using mathematical

R. E. Cutts; S. E. Burns

2010-01-01

152

Leveraging Process Knowledge to Improve Modeling of Evaporation Rate Data for Agent Fate Wind Tunnels.  

National Technical Information Service (NTIS)

PURPOSE OF TALK: (1) Demonstrate how the modeling (regression analysis) of evaporation rate data can be improved by rescaling the variables based on knowledge of the process (2) Describe how running the experimental design trials in specific randomized bl...

T. A. Donnelly

2007-01-01

153

Theoretical investigation of the injection and evaporation of water in a hydrogen/oxygen steam generator  

NASA Astrophysics Data System (ADS)

Water is injected into the gas stream for the purpose of cooling the reaction products resulting from the stochiometric combustion of hydrogen with oxygen. The penetration of the jet decisively influences the temperature profile across the flow cross section in the water vapor. The penetration of the water jet into the stream is calculated using the jet shedding model and compared with the garden hose model. Models for the evaporation of water droplets in superheated steam are developed for calculating the evaporation paths. The parameters which influence the injection and evaporation process are subjected to variation and their effects in the evaporation paths are analyzed.

Beer, Stefan

1991-07-01

154

Role of transpiration suppression by evaporation of intercepted water in improving irrigation efficiency  

Microsoft Academic Search

Sprinkler irrigation efficiency declines when applied water intercepted by the crop foliage, or gross interception (Igross), as well as airborne droplets and ponded water at the soil surface evaporate before use by the crop. However, evaporation of applied water can also supply some of the atmospheric demands usually met by plant transpiration. Any suppression of crop transpiration from the irrigated

J. A. Tolk; T. A. Howell; J. L. Steiner; D. R. Krieg; A. D. Schneider

1995-01-01

155

EVAPORATION FROM WATER SURFACES IN MOUNTAIN AREAS OF WESTERN UNITED STATES  

Microsoft Academic Search

Large amounts of water are lost from reservoirs and lakes by evaporation. Thus, measurements are being made of evaporation from free-water surfaces throughout the world. In the Western United States the storage of stream flow from mountain watersheds in reservoirs has made possible the development of much of the irrigated agriculture. These reservoirs help to prevent floods, conserve a water

HARRY F. BLANEY

1960-01-01

156

Arsenic resistant microorganisms isolated from agricultural drainage water and evaporation pond sediments  

Microsoft Academic Search

Elevated levels of As in contaminated water and soil could pose a major threat to the environment. Relatively high levels of As have been reported in agricultural drainage water and in evaporation pond sediments in Kern County, California. The objective of this study was to enumerate and isolate As-resistant microorganisms from agricultural drainage water and evaporation pond sediments and to

K. Davis Huysmans; W. T. Frankenberger

1990-01-01

157

Evaporation From Lake Superior  

NASA Astrophysics Data System (ADS)

Evaporation is a critical component of the water balance of each of the Laurentian Great Lakes, and understanding the magnitude and physical controls of evaporative water losses are important for several reasons. Recently, low water levels in Lakes Superior and Michigan/Huron have had socioeconomic, ecological, and even meteorological impacts (e.g. water quality and quantity, transportation, invasive species, recreation, etc.). The recent low water levels may be due to increased evaporation, but this is not known as operational evaporation estimates are currently calculated as the residual of water or heat budgets. Perhaps surprisingly, almost nothing is known about evaporation dynamics from Lake Superior and few direct measurements of evaporation have been made from any of the Laurentian Great Lakes. This research is the first to attempt to directly measure evaporation from Lake Superior by deploying eddy covariance instrumentation. Results of evaporation rates, their patterns and controlling mechanisms will be presented. The direct measurements of evaporation are used with concurrent satellite and climate model data to extrapolate evaporation measurements across the entire lake. This knowledge could improve predictions of how climate change may impact the lake's water budget and subsequently how the water in the lake is managed.

Spence, C.; Blanken, P.; Hedstrom, N.; Leshkevich, G.; Fortin, V.; Charpentier, D.; Haywood, H.

2009-05-01

158

Contrasting the Evaporation and Condensation of Water from Glassy and Amorphous Aerosol Particles  

NASA Astrophysics Data System (ADS)

The partitioning of water between the condensed and gas phases in atmospheric aerosol is usually assumed to occur instantaneously and to be regulated by solution thermodynamics. However, the persistence of high viscosity, glassy and amorphous aerosol to low relative humidity without crystallisation occurring is now widely recognised, suggesting that the timescale for water transport to or from the particle during condensation or evaporation may be significant. A kinetic limitation on water transport could have important implications for understanding hygroscopic growth measurements made on ambient particles, the ability of particles to act as ice nuclei or cloud condensation nuclei, the kinetics of chemical aging/heterogeneous chemistry, and the rate or condensation/evaporation of semi-volatile organic components. In this study we will report on measurements of the timescale of water transport to and from glassy aerosol and ultra-high viscosity solution droplets using aerosol optical tweezers to investigate the time-response of single particles to changes in relative humidity. As a benchmark system, mixed component aerosol particles containing sucrose and sodium chloride have been used; varying the mole fractions of the two solutes allows a wide range of solution viscosities to be studied. We will show that coarse particles can take many thousands of seconds to equilibrate in size and that the timescale correlates with the estimated bulk viscosity of the particle. We will also confirm that significant inhomogeneities in particle composition can be established during evaporation or condensation. Using the experimental data to benchmark a model for equilibration time, predictions can be made of the timescale for the equilibration of accumulation mode particles during water condensation or evaporation and these predictions will be described and their significance explored. Finally, the coalescence dynamics of highly viscous aerosol particles will be reported, reporting for the first time the timescale required for coalesced particles to relax to an equilibrium morphology and size.

Reid, J. P.; Bones, D. L.; Power, R.; Lienhard, D.; Krieger, U. K.

2012-04-01

159

Evaluation of the correlations for predicting evaporative loss from water body  

SciTech Connect

Water evaporation (evaporation from here on) is a natural phenomenon that is important for system design and system safety in many engineering branches. Indeed, evaporative heat and mass loss are observed and calculated in very diverse situations, such as irrigation plants, water purification plants, cooling ponds, lakes, dams, swimming pools, health spas, management of liquid wastes as in evaporation pools, and spent fuel pools in nuclear power plants. There are a number of correlations obtained from experimental studies that predict the evaporative heat and mass loss from a water body. This study aims to summarize and to compare the existing evaporation correlations to determine the upper and lower bounding correlations for use in various thermal-hydraulic analyses of systems. Currently and widely used, six correlations found in the literature have been selected and tested using the major parameters of evaporation such as water temperature, air relative humidity, air velocity, and temperature. The comparison test cases show that ASHRAE (1991) and Ryan et al. (1974) equations result in the highest evaporative loss, while the Brady et al. (1969) equation provides the lowest evaporative loss in most conditions. Engineering designers may sometimes need the upper bound value of evaporative loss or sometimes the lower bound value for a conservative calculation. The authors conclude that using a single equation does not provide the conservative calculation for every situation and show which correlation gives the lower or upper bound for different conditions.

Yilmaz, T.P.; Aybar, H.S.

1999-07-01

160

PHASE EQUILIBRIA AND EVAPORATION RATES IN A FOUR COMPONENT EMULSION  

Microsoft Academic Search

The cosmetic system of water, lecithin, polyethylene glycol (M. W. 5000), and white oil was studied and the phase diagram determined using visual observation, low angle x-ray diffraction and chemical analysis.The results showed the lecithin \\/ water lamellar liquid crystal to be retained when the polyethylene glycol was gradually replaced by white oil. The polyethylene glycol was solubilized in the

Teanoosh Moaddel; Stig E. Friberg

1995-01-01

161

Emergent relation between surface vapor conductance and relative humidity profiles yields evaporation rates from weather data  

PubMed Central

The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (Csurf). Csurf accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of Csurf to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that land–atmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (arid–humid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and Csurf can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle.

Salvucci, Guido D.; Gentine, Pierre

2013-01-01

162

Orientation Dependence of the Evaporation Rate of CdS Single Crystals  

Microsoft Academic Search

The vacuum evaporation characteristics of the (0001), (112¯0), and (101¯0) crystal faces of CdS single crystals have been measured in the temperature range of 680°–760°C. From the temperature dependence of the rate, the activation energy of the surface reaction which controls the vaporization of (0001) and (112¯0) faces has been determined. Semisphere shaped crystals are used to study the evaporation

G. A. Somorjai; N. R. Stemple

1964-01-01

163

Performance of constructed evaporation ponds for disposal of smelter waste water  

Microsoft Academic Search

The construction of evaporative ponds and wetlands for the disposal of waste water high in ionic concentrations is a waste disposal strategy currently considered by many industries. However, the design, construction and management of these ponds and wetlands are not straightforward as complex chemical interactions result in both spatial and temporal changes in water quality. The effects of evaporation and

S. A Salzman; G Allinson; F Stagnitti; M Coates; R. J Hill

2001-01-01

164

Measurement of Evaporation from Lakes and Ponds in Florida.  

National Technical Information Service (NTIS)

Hydrological models often calculate evaporation in terms of corrections to evaporation pan data. A more satisfactory approach would be to estimate evaporation rates in terms of the turbulent transport processes which govern the diffusion of water vapor in...

J. F. Bartholic R. G. Bill L. H. Allen

1978-01-01

165

Treatment of a waste oil-in-water emulsion from a copper-rolling process by ultrafiltration and vacuum evaporation.  

PubMed

A process is proposed for the treatment of a waste oil-in-water (O/W) emulsion generated in an industrial copper-rolling operation. The use of demulsifier agents improves the subsequent treatment by techniques such as ultrafiltration (UF) or evaporation. The effluent COD is reduced up to 50% when the O/W emulsion is treated by UF using a flat 30 nm TiO(2) ceramic membrane (?P = 0.1 MPa) and up to 70% when it is treated by vacuum evaporation, after an emulsion destabilization pretreatment in both cases. Increases in the UF permeate flux and in the evaporation rate are observed when a chemical demulsifier is used in the pretreatment step. A combined process consisting of destabilization/settling, UF, and vacuum evaporation can yield a very high-quality aqueous effluent that could be used for process cooling or emulsion reformulation. PMID:21112152

Gutiérrez, Gemma; Lobo, Alberto; Benito, José M; Coca, José; Pazos, Carmen

2010-11-02

166

Bioheat model evaluations of laser effects on tissues: role of water evaporation and diffusion  

NASA Astrophysics Data System (ADS)

A two-dimensional, time-dependent bioheat model is applied to evaluate changes in temperature and water content in tissues subjected to laser irradiation. Our approach takes account of liquid-to-vapor phase changes and a simple diffusive flow of water within the biotissue. An energy balance equation considers blood perfusion, metabolic heat generation, laser absorption, and water evaporation. The model also accounts for the water dependence of tissue properties (both thermal and optical), and variations in blood perfusion rates based on local tissue injury. Our calculations show that water diffusion would reduce the local temperature increases and hot spots in comparison to simple models that ignore the role of water in the overall thermal and mass transport. Also, the reduced suppression of perfusion rates due to tissue heating and damage with water diffusion affect the necrotic depth. Two-dimensional results for the dynamic temperature, water content, and damage distributions will be presented for skin simulations. It is argued that reduction in temperature gradients due to water diffusion would mitigate local refractive index variations, and hence influence the phenomenon of thermal lensing. Finally, simple quantitative evaluations of pressure increases within the tissue due to laser absorption are presented.

Nagulapally, Deepthi; Joshi, Ravi P.; Thomas, Robert J.

2011-02-01

167

Evaporation of water from air-fluidized porous particles  

Microsoft Academic Search

The drying rate of wetted porous silica–alumina particles, FCC catalyst, was measured in a 15cm diameter air-fluidized bed with a cloth distributor, containing about 1.5kg catalyst. The particles tolerated the addition of remarkably large quantities of liquid water, up to 50% of the dry weight, without upsetting the fluidization characteristics: evidently the water was accommodated within the porous particle structure.

J. F Davidson; R. B Thorpe; O Al-Mansoori; H Kwong; M Peck; R Williamson

2001-01-01

168

What determines drying rates at the onset of diffusion controlled stage-2 evaporation from porous media?  

NASA Astrophysics Data System (ADS)

Early stages of evaporation from porous media are marked by relatively high evaporation rates supplied by capillary liquid flow from a receding drying front to vaporization surface. At a characteristic drying front depth, hydraulic continuity to the surface is disrupted marking the onset of stage-2 evaporation where a lower evaporative flux is supported by vapor diffusion. Observations suggest that in some cases the transition is accompanied by a jump in the vaporization plane from the surface to a certain depth below. The resulting range of evaporation rates at the onset of stage-2 is relatively narrow (0.5-2.5 mm d-1). The objective is to estimate the depth of the vaporization plane that defines vapor diffusion length at the onset of stage-2. The working hypothesis is that the jump length is determined by a characteristic length of connected clusters at the secondary drying front that obeys a power law with the system's Bond number. We conducted evaporation experiments using sands and glass beads of different particle size distributions and extracted experimental data from the literature for model comparison. Results indicate the jump length at the end of stage-1 was affected primarily by porous media properties and less so by boundary conditions. Results show power law relationships between the length of the vaporization plane jump and Bond number with an exponent of -0.48 in good agreement with the percolation theory theoretical exponent of -0.47. The results explain the origins of a relatively narrow range of evaporation rates at the onset of stage-2, and provide a means for estimating these rates.

Shokri, N.; Or, D.

2011-09-01

169

Sonolysis of organic liquid: effect of vapour pressure and evaporation rate  

Microsoft Academic Search

Various kinds of organic liquids, such as hydrocarbons, ethers, ketones and alcohols, were subjected to ultrasonic irradiation and the effects of vapour pressure and evaporation rate of the liquids on decomposition rates and the distribution of decomposition products were investigated. The main decomposition products from hydrocarbons were hydrogen, methane, ethylene and acetylene, and hydrogen, methane, ethylene, carbon monoxide and aldehydes

Yoshiteru Mizukoshi; Hiroshi Nakamura; Hiroshi Bandow; Yasuaki Maeda; Yoshio Nagata

1999-01-01

170

The influence of evaporation rate on the domain structures of permalloy and cobalt small magnetic particles  

NASA Astrophysics Data System (ADS)

The magnetic properties of regular particles of cobalt and permalloy fabricated by electron beam lithography and evaporation, have been studied as a function of their growth rate. As the growth rate is decreased, the very regular multi-domain structures normally supported by the particles are replaced by a single domain state perturbed by magnetization ripple.

Wong, H. Y.; Chapman, J. N.; McVitie, S.; Hefferman, S. J.

1992-02-01

171

TEE EFFECIS OF EXTENDED THIN FILM EVAPORATION AND EXPWNAL DIFFUSION RESISTANCE DURING THE CONSTANT DRYING RATE PERIOD  

Microsoft Academic Search

Extended thin film evaporation with external diffusion resistance is analyzed for the constant rate period of the drying process, in which a polar liquid evaporates from porous bodies made of glass. The extended thin film is defined as the Liquid film in which the disjoining pressure dominates the fluid flar field and works as the driving force replenishing the evaporating

Maw Tien Lee; Jer Ru Maa

1992-01-01

172

Measurement of the evaporation mass flow rate in a horizontal liquid layer partly opened into flowing gas  

NASA Astrophysics Data System (ADS)

The dynamics of evaporation from a local surface of a horizontal liquid layer under a gas flow is studied experimentally. The average evaporation mass flow rate of a liquid layer (HFE-7100) induced by inert gas (nitrogen) is measured using two independent methods. The influence of the average gas flow rate, gas and liquid temperature, and the layer depth upon the evaporation rate and convection in the liquid layer is investigated. Correlation dependences of the evaporation rate vs. the inert gas flow rate and temperature are obtained. It is found that the average evaporation-rate curve has a local maximum with a growth of the liquid layer depth. With the growth of the gas and liquid temperature, the local maximum in an evaporation flow rate of the liquid layer is shifted to the larger value of the liquid depth.

Lyulin, Yu. V.; Kabov, O. A.

2013-09-01

173

Effects of the Al cathode evaporation rate on the performance of organic solar cells  

NASA Astrophysics Data System (ADS)

In this study, the effects of the interface structure between Al cathode and polymer photo-active thin film are investigated regarding the performance of bulk heterojunction polymer solar cells by changing the Al cathode e-beam evaporation rate. The formation of Al-polymer complex interlayers increases open circuit voltage (Voc) above 0.7 V while decreasing the short circuit current and fill factor. These can be improved, however, without much loss of Voc by increasing the evaporation rate, which results in power conversion efficiency enhancement from 1.35% to 3.6%.

Kim, Junwoo; Kim, Jung-Su; Kwak, Sun-Woo; Yu, Jong-Su; Jang, Yunseok; Jo, Jeongdai; Lee, Taik-Min; Kim, Inyoung

2012-11-01

174

Evaporation rate and composition monitoring of electron beam PVD processes  

SciTech Connect

Lawrence Livermore National Laboratory (LLNL) is developing sensor and control technology to improve the quality and range of applicability of electron beam PVD. The approach being developed uses tunable lasers to measure, the density and composition of the vapor plume. This paper reviews the principles of operation of laser based sensors and discusses data from experiments in which titanium and niobium are co-vaporized. Laser data agreed well with deposited film compositions and spatial variations in deposited film cross sections. Laser based vapor monitoring appears to have broad applicability and has the potential to extend the use of high rate electron beam PVD.

Anklam, T.M.; Berzins, L.V.; Braun, D.G.; Haynam, C.; Meier, T.; McClelland, M.A.

1995-03-01

175

Indirect evaporative cooling potential in air–water systems in temperate climates  

Microsoft Academic Search

Recent developments have prompted a review of evaporative cooling technology as an effective means of cooling modern deep plan buildings. Prominent among these developments is the success of high temperature sensible cooling systems, particularly, chilled ceilings, which require a supply of cooling water at 14–18°C. Crucial to the success of evaporative cooling technology, as a significant means of cooling in

Ben Costelloe; Donal Finn

2003-01-01

176

Evaporative heat transfer characteristics of a water spray on micro-structured silicon surfaces  

Microsoft Academic Search

Experiments were performed to evaluate the evaporative heat transfer characteristics of spray cooling of water on plain and micro-structured silicon surfaces at very low spray mass fluxes. The textured surface is made of an array of square micro-studs. It was found that the Bond number of the microstructures is the primary factor responsible for the heat transfer enhancement of evaporative

Cheng-Chieh Hsieh; Shi-Chune Yao

2006-01-01

177

Evaporation from seven reservoirs in the Denver water-supply system, central Colorado  

USGS Publications Warehouse

Seven reservoirs in central Colorado, operated by the Denver Board of Water Commissioners, were studied during 1967-73 to determine evaporation losses. These reservoirs, Elevenmile Canyon, Dillon, Gross, Antero, Cheesman, Williams Fork, and Ralston, are located on both sides of the Continental Divide. Methods for computing evaporation include energy-budget, mass-transfer, and pan relationships. Three reservoirs, Elevenmile Canyon, Dillon, and Gross, had mass-transfer coefficients calibrated by energy-budget studies. At the remaining reservoirs, an empirical technique was used to estimate the mass-transfer coefficient. The enery-budget-calibrated methods give the most accurate evaporation values; the empirical coefficients give only a best estimate of evaporation. All reservoirs should be calibrated by energy-budget studies. The pan method of computing evaporation is the least reliable method because of problems of advected energy through the sides of the pan, representative pan exposure , and the irregularity of ratios of reservoir to pan evaporation. (Woodard-USGS)

Ficke, John F.; Adams, D. Briane; Danielson, T. W.

1977-01-01

178

Single-droplet evaporation kinetics and particle formation in an acoustic levitator. Part 1: evaporation of water microdroplets assessed using boundary-layer and acoustic levitation theories.  

PubMed

The suitability of a single droplet drying acoustic levitator as a model for the spray drying of aqueous, pharmaceutically-relevant solutes used to produce protein-loaded particles has been examined. The acoustic levitator was initially evaluated by measuring the drying rates of droplets of pure water in dependence of drying-air temperature and flow rate. The measured drying rates were higher than those predicted by boundary layer theory because of the effects of primary acoustic streaming. Sherwood numbers of 2.6, 3.6, and 4.4 at drying-air temperatures of 25 degrees C, 40 degrees C, and 60 degrees C were determined, respectively. Acoustic levitation theory could predict the measured drying rates and Sherwood numbers only when a forced-convection drying-air stream was used to neuralize the retarding effect of secondary acoustic streaming on evaporation rate. At still higher drying-air flow rates, the Ranz-Marshall correlation accurately predicts Sherwood number, provided a stable droplet position in the standing acoustic wave is maintained. The measured Sherwood numbers and droplet Reynolds numbers show that experiments performed in the levitator in still air are taking place effectively under conditions of substantial forced convection. The similitude of these values to those occurring in spray dryers is fortuitous for the suitability of the acoustic levitator as a droplet evaporation model for spray drying. PMID:17582811

Schiffter, Heiko; Lee, Geoffrey

2007-09-01

179

Characteristics of the Self-evaporation Behavior of Sprinkled Water near the Triple Point  

NASA Astrophysics Data System (ADS)

For the sake of capturing the basic data in concern with the designing of vacuum evaporation apparatus, characteristics of the self-evaporation behavior of sprinkled water near the triple point has been investigated experimentally. The relationship between the amount of the vaporized water and the pressure in the vessel was elucidated quantitatively on the condition that over-heated water was sprinkled from water supplying nozzles of diameter of 4 mm into the center of the steam area in the heat insulation glass evaporation vessel having diameter of 200 mm and height of 1100 mm. Even under the mild water sprinkling conditions such as no small particle formation, small Reynolds number, and small Weber number, the temperature effectiveness of the self-evaporation in the center of the steam was as high as 80%, which clearly shows the effectiveness of this water-sprinkling method. In addition, the basic data for system designing such as water evaporation coefficient from water layer surface and temperature effectiveness of self-evaporation during the f1ight in the steam space were obtained.

Aizawa, Kazuo; Hayashi, Kanetoshi; Ogoshi, Hidemasa; Maeyama, Katsuya; Yonezawa, Noriyuki

180

Finite size effects in the evaporation rate of 3 He clusters  

Microsoft Academic Search

We have computed the density of states and the evaporation rate of3He clusters, paying special attention to finite size effects which modify the3He level density parameter and chemical potential from their bulk values. Ready-to-use liquid-drop expansions of these quantities are given.

A. Guirao; M. Pi; M. Barranco

1991-01-01

181

Convection and evaporation rate of planar liquid films subjected to impulsive superheating  

Microsoft Academic Search

The interfacial stability, convective structure, and evaporation rate of upward-facing, thin liquid films were studied experimentally. Four different working fluids were used. Films initially 5 mm to 100 mum thick were subjected to impulsive superheating. The films resided on a temperature controlled, gold-plated copper surface in a closed, initially degassed test chamber. Superheating was achieved by suddenly dropping the pressure

J. T. Kimball; J. C. Hermanson; J. S. Allen

2010-01-01

182

Two-layer integral model for calculating the evaporation rate from a liquid surface  

Microsoft Academic Search

An integral model is presented for predicting the evaporation rate from a single component liquid layer exposed to wind. This approach simplifies the solution of the convection–diffusion equation by averaging over the height of the concentration boundary-layer thickness. The model is valid for hydraulically smooth as well as rough surfaces and yields results which are in good agreement with those

J. P. Kunsch

1998-01-01

183

Steady-State and Extinction Analyses of Counterflow Spray Diffusion Flames with Arbitrary Finite Evaporation Rate  

Microsoft Academic Search

We present a new analysis of the behavior of counterflow spray diffusion flames in which the droplets are permitted to evaporate at a finite rate. The effects of fuel volatility, droplet size, and liquid fuel loading on steady-state combustion and conditions for extinction are investigated. We treat instances in which (1) the flame front is located beyond the stagnation plane

A. Dvorjetski; J. B. Greenberg

2002-01-01

184

Investigation of annular flow at high evaporation rates in view of liquid film cooling  

Microsoft Academic Search

The process of liquid film cooling of combustion chamber walls which are subjected to extremely high heat rates was investigated. A theoretical model was developed for a reliable prediction of the film cooling length. The mass transfer at the liquid-gas interface results from evaporated liquid and entrained liquid droplets. The film cooling length analysis, which includes the physical effects in

Juergen Nahstoll

1988-01-01

185

Technique for Measurements of the Evaporation Rate of Single, Freely Falling, Droplets  

Microsoft Academic Search

An ex perimental setup has been developed in order to determine evaporation rates of freely falling droplets. The droplets may consist of pure liquids, of a mixture of different liquids, or of a solution. After a droplet has been produced by a droplet on deman d generator, it falls downwards along a vertical observation channel. Meanwhile a laser beam is

N. Roth; J. Wilms; B. Weigand

186

The temperature variance method: a powerful tool in the estimation of actual evaporation rates  

Microsoft Academic Search

The usefulness of the temperature variance technique for the estimation of actual evaporation rates under humid tropical conditions was tested with a set of micrometerolo gical data collected above a 6- year-old pine plantation in Viti Levu, Fiji. Values for the sensible and latent heat fluxes obtained from the standard deviations of fast responding dry and wet bulb thermocouples during

H. F. VUGTS; M. J. WATERLOO; F. J. BEEKMAN; K. F. A. FRUMAU; L. A. BRUUNZEEL

1993-01-01

187

EFFECT OF HEATING RATE ON EVAPORATIVE HEAT LOSS IN THE MICROWAVE-EXPOSED MOUSE  

EPA Science Inventory

Male CBA/J mice were administered heat loads of 0-28 J. per g at specific absorption rates (SARs) of either 47 or 93 W. per kg by exposure to 2,450-MHz microwave radiation at an ambient temperature of 30 C while evaporative heat loss (EHL) was continuously monitored with dew-poin...

188

PREDICTING EVAPORATION RATES AND TIMES FOR SPILLS OF CHEMICAL MIXTURES: JOURNAL ARTICLE  

EPA Science Inventory

NRMRL-CIN-0988 Smith*, R.L. Predicting Evaporation Rates and Times for Spills of Chemical Mixtures. The Annals of Occupational Hygiene (Ogden, T. (Ed.), Elsevier) 45 (6):437-445 (2001). EPA/600/J-00/125. 03/16/2000 Spreadsheet and short-cut methods have been developed for p...

189

Estimates of spatial variation in evaporation using satellite-derived surface temperature and a water balance model  

Microsoft Academic Search

Evaporation dominates the water balance in arid and semi-arid areas. The estimation of evaporation by land-cover type is important for proper management of scarce water resources. Here, we present a method to assess spatial and temporal patterns of actual evaporation by relating water balance evaporation estimates to satellite-derived radiometric surface temperature. The method is applied to a heterogeneous landscape in

Laurens M. Bouwer; Trent W. Biggs; Jeroen C. J. H. Aerts

2008-01-01

190

Experimental investigation on some key variables during pool water flash evaporation  

NASA Astrophysics Data System (ADS)

An experimental study has been performed to investigate pool water flash evaporation in a rectangle chamber. The water level was at 40 mm, 60 mm, 100 mm, and 150 mm. Initial conditions of the liquid varied from 36 to 88° C temperature and 2.1 to 48° C superheat. The experimental results showed that the initial water temperature, the superheat and the water level are significant to the water temperature transients in flashing process and the value of NEF when flash evaporation calm down. Experimental study allows us to correlate the evolution of water temperature.

Guo, Y. L.; Yan, J. J.; Chong, D. T.; Liu, J. P.

2010-03-01

191

Effect of water vapor diffusion enhancement on soil moisture\\/temperature and evaporation - A numerical study  

Microsoft Academic Search

Experimental and numerical studies concerning the coupled flow of liquid water and water vapor in porous media have shown differences in observed and Fickian diffusion-based modeled water vapor fluxes. Early studies explain these differences with evaporation-condensation effects in liquid islands in the variably saturated zone and enhanced water vapor flux due to local thermal gradients which differ between the different

Christian Steenpass; Jan Vanderborght; Johan Alexander Huisman

2010-01-01

192

Cold {sup 52}Cr elastic and inelastic collision-rate determination using evaporative cooling analysis  

SciTech Connect

Elastic and inelastic collision-rate constants of {sup 52}Cr in the temperature range of 20 mK to 1 K are inferred from the evaporative cooling of buffer gas loaded atomic chromium. Using a model that describes the dynamics of the trapped chromium cloud during evaporation, we find g{sub el}=2.15(+2.5,-1.2)x10{sup -10} cm{sup 3}/s and g{sub in}=1.36(+1.2,-0.7)x10{sup -12} cm{sup 3}/s, consistent with theory but in disagreement with previously reported measurements.

Nguyen, Scott V.; Carvalho, Robert de; Doyle, John M. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2007-06-15

193

Investigation of annular flow at high evaporation rates in view of liquid film cooling  

NASA Astrophysics Data System (ADS)

The process of liquid film cooling of combustion chamber walls which are subjected to extremely high heat rates was investigated. A theoretical model was developed for a reliable prediction of the film cooling length. The mass transfer at the liquid-gas interface results from evaporated liquid and entrained liquid droplets. The film cooling length analysis, which includes the physical effects in detail, is separated into two regions: heating the liquid and evaporating the liquid. The theoretical results were experimentally verified at high pressures and temperatures using a modified H2/O2-rocket motor. There is a good agreement between the theoretical and the experimental results over the experimental range.

Nahstoll, Juergen

1988-01-01

194

Comparison of techniques for estimating evaporation from an irrigation water storage  

NASA Astrophysics Data System (ADS)

With the emergence of water supply and food security issues as a result of increasing population and climate change pressures, the need for efficient use of available water supplies is paramount. Management of available resources and improved efficiency require accurate specification of evaporation, which is a major water loss pathway, yet evaporation remains difficult to accurately quantify. This study uses scintillometry-derived measurements of evaporation to test the performance of water balance, pan coefficient, and combination modeling techniques, which might commonly be used by resource managers. Both pan coefficient and water balance techniques performed poorly, but the Penman-Monteith model with local site data and site-specific wind function produced estimates within 2% of those measured. Recognizing that such a model parameterization would rarely be a possibility in most environments, further testing involving the range of data sets that might be available for a location was undertaken. Modeling using over-water measurements and, generally, applicable wind functions from the literature produced estimates 26% greater than those measured. Estimates within 12% of those measured were made for the equivalent model setup using over-land meteorological data; however, when data from the nearest meteorological station was used, this difference increased to 27%. The different evaporation estimation techniques tested were shown to produce a range of estimates of water availability, which varied by nearly 30%. The large differences between measured and predicted evaporation highlight the uncertainty that still exists in evaporation estimation and the sensitivity of predictions to the source of input data.

McJannet, D. L.; Cook, F. J.; Burn, S.

2013-03-01

195

PROCESS WATER BUILDING, TRA605. INSIDE A FLASH EVAPORATOR. INL NEGATIVE ...  

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

PROCESS WATER BUILDING, TRA-605. INSIDE A FLASH EVAPORATOR. INL NEGATIVE NO. 3323. Unknown Photographer, 9/12/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

196

Development of a new laboratory evaporation measurement device as decision support for evaporation-optimized building  

Microsoft Academic Search

A new laboratory evaporation measurement device (LEMD) was developed to estimate the evaporation rates of urban surface materials. Here, evaporation is induced by means of a constant heat input and airflow. The evaporation can be measured using two different methods concurrently. Method 1 is based on a balance, which measures the mass loss over time. In method 2 the water

P. Starke; C. Wallmeyer; S. Rölver; P. Göbel; W. G. Coldewey

197

Reaction and Evaporation Rates of High Temperature Candidate Fluids from a TFOST Test  

Microsoft Academic Search

Five high temperature fluids have been evaluated in a thin-film oxidation sealed tube (TFOST) test at 300°C to assess their capability for high temperature application. Degradation maps were constructed for each individual lubricant based on the amount of fresh lubricant remaining. Liquid-phase and gas-phase reaction rates and evaporation rate were then calculated and plotted against test time to illustrate their

Kenneth K. Chao; Costandy S. Saba

1997-01-01

198

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable climatic conditions.

J. Boysen; J. Morotti

1993-01-01

199

Monitoring near surface soil water and associated dynamics of infiltration and evaporation fluxes  

Technology Transfer Automated Retrieval System (TEKTRAN)

In-situ monitoring of soil water has the advantage of integrating the precipitation, evaporation history, and gradual changes in hydraulic properties on the aggregate response of the system, which is manifested as soil water storage. Near-surface soil water and temperature dynamics were monitored th...

200

Reduced energy consumption evaporator for use in desalting impaired waters. Technical completion report (Final)  

Microsoft Academic Search

The basic objective of this program is to demonstrate significant savings in energy consumption by the use of the wiped film rotating disk (WFRD) evaporator in a five-effect vapor compression distillation (MEVCD) system to recover the maximum amount of water from agricultural drainage water and other impaired waters. Tests were conducted using a 10,000 ppm aqueous solution of sodium sulfate

B. W. Tleimat; M. C. Tleimat

1995-01-01

201

Experimental Study of the Thermophoretic Force and Evaporation Rates for Single Microparticles in Knudsen Regime  

Microsoft Academic Search

Elastic and inelastic light scattering techniques were used to explore the processes of Knudsen evaporation, thermophoresis and gas\\/droplet reaction related to single microparticles. The reaction between single titanium ethoxide (TTE) droplets with water vapor was investigated. It was found that the fast surface reaction led to the formation of a coated microsphere consisting of a TiO_2 shell and an unreacted

Wanguang Li

1995-01-01

202

Hydroclimatology of Illinois: A comparison of monthly evaporation estimates based on atmospheric water balance and soil water balance  

Microsoft Academic Search

Here we describe the regional-scale hydrological cycle of Illinois, including both the land and atmospheric branches, using a data set on most of the hydrological variables, i.e., precipitation, streamflow, soil water content, snow depth, groundwater level, and atmospheric flux of water vapor. Since direct observations of evaporation are not available, two different approaches, soil water balance and atmospheric water balance,

Pat Jen-Feng Yeh; Michelle Irizarry; Elfatih A. B. Eltahir

1998-01-01

203

Variation of Phreatic Evaporation of Bare Soil and Integration Application in Water Allocation in Shule Basin  

NASA Astrophysics Data System (ADS)

Phreatic evaporation is a key element in regional water balance, but it is hardly measured directly. Recently the development of some new technologies brings new dawn to phreatic evaporation measurement, such as eddy covariance, remote sensing ET and so on. But the new technologies have no ability to connect to groundwater yet. Conventional groundwater balance equipment was set up in Shule basin in northwestern China, with located E97°01', N45°13' , altitude 1520m, annual average precipitation 61.8mm and annual evaporation 2600mm (pan 20cm). The experiment field contains 45 lysimeters (65cm diameter). 11 different water table depths are set in the lysimeters, which are 0.5m, 0.75m, 1.0m, 1.25m, 1.5m, 2.0m, 2.5m, 3.0m, 4.0m, 5.0m and 6.0m. The water table in the lysimeter is controlled by Marriott Bottle System. The evaporation and percolation is measured for three different soil types (silt sandy soil, loam soil and clay soil) in the 11 different water table depths. Based on the data from 2006 to 2010, the influences of atmosphere evaporation capacity, phreatic water depth and soil textures are analyzed. Empirical formulae for estimating phreatic evaporation are regressed. The fitting precision of the different formulae are evaluated. The results show that, fitting effect of common empirical formulae is good in Shule river basin. For the different soil types, fitting effect of silt soil is the best, while that of clay soil is relatively low. At last, formulae fitted in other areas and phreatic evaporation tests are summarized. The reasons of difference of fitted coefficients lie in three aspects: the range of depth of groundwater, choice of the value of water evaporation, method to optimize coefficients. Physical meaning of the coefficients in empirical formulae is analyzed. The features, fitting effect and notes in application of formulae are evaluated. The results are applied in water requirement calculation of ecological conservation Dunhuang Xihu Nature Reserve. Water sources, plant transpiration, and phreatic evaporation are simulated by the groundwater numerical model and the total ET of nature reserve is calculated. The supplementary water requirement is advanced. Key words: phreatic evaporation; empirical formulae; fitting precision; Shule river basin

Wang, Z.; Huang, P.; Gong, G.

2011-12-01

204

Wet canopy evaporation rate of three stands in Western Sichuan, China  

Microsoft Academic Search

The wet canopy evaporation rate (Er) was calculated by Penman-Monteith combination model based on three assumptions and with meteorological variables 2 m above\\u000a the canopy in three stands, dominated by spruce (SF), fir (FF) and birch (BF) trees, respectively, in the subalpine forests\\u000a in western Sichuan, China over a growing season. The total amount of theE was 44.5 mm for

Yang Wanqin; Wang Kaiyun; Seppo Kellomäki; Xiao Ling

2004-01-01

205

Effect of contact angle hysteresis on water droplet evaporation from super-hydrophobic surfaces  

Microsoft Academic Search

Small water drops demonstrate different evaporation modes on super-hydrophobic polymer surfaces with different hysteresis of contact angle. While on the high-hysteresis surface evaporation follows the constant-contact-diameter mode, the constant-contact-angle mode dominates on the low-hysteresis surface. These modes were previously reported for smooth hydrophilic and hydrophobic surfaces, respectively. The experimental data are compared to the previous models describing spherical cap drops

S. A. Kulinich; M. Farzaneh

2009-01-01

206

Airborne exposure to trihalomethanes from tap water in homes with refrigeration-type and evaporative cooling systems.  

PubMed

This study evaluates airborne concentrations of common trihalomethane compounds (THM) in selected living spaces of homes supplied with chlorinated tap water containing >85 ppb total THM. Three small homes in an arid urban area were selected, each having three bedrooms, a full bath, and approximately 1000 square feet; two homes had standard (refrigeration-type) central air conditioning and the third had a central evaporative cooling system ("swamp cooler"). A high-end water-use pattern was used at each home in this exposure simulation. THM were concurrently measured on 4 separate test days in tap water and air in the bathroom, living room, the bedroom closest to the bathroom, and outside using Summa canisters. Chloroform (trichloromethane, TCM), bromodichloromethane (BDCM), and dibromochloromethane (DBCM) concentrations were quantified using U.S. EPA Method TO-14. The apparent volatilization fraction consistently followed the order: TCM > BDCM > DBCM. Relatively low airborne THM concentrations (similar to outdoors) were found in the living room and bedroom samples for the home with evaporative cooling, while the refrigeration-cooled homes showed significantly higher THM levels (three- to fourfold). This differential remained after normalizing the air concentrations based on estimated THM throughput or water concentrations. These findings indicate that, despite higher throughput of THM-containing water in homes using evaporative coolers, the higher air exchange rates associated with these systems rapidly clears THM to levels similar to ambient outdoor concentrations. PMID:15799243

Kerger, Brent D; Suder, David R; Schmidt, Chuck E; Paustenbach, Dennis J

2005-03-26

207

Measurement of evaporative water loss in small animals by dew-point hygrometry.  

PubMed

This paper presents the procedures and equations to be utilized for measurement of evaporative water loss (mw), by use of the dew-point hygrometer, in small animals exposed to air containing water vapor in an open-flow system. The system accounted accurately for the water evaporated from a bubble flask. In addition, hygrometric measurements of pulmocutaneous mw in pigeons (Columba livia, mean mass 0.31 kg) agreed closely with simultaneous gravimetric measurements, utilizing a desiccant in the sample stream, in a manner independently of air temperature (Ta, 20 or 40 degrees C), ambient water vapor pressure (PW, 4-16 10(2) Pa), or mw (5-66 mg-min-1). Evaporation in pigeons was independent of PW at 20 degrees C, but increased with decreasing PW at 40 degrees C, suggesting differences in ventilatory adjustments to changes in PW at the two temperatures. PMID:893300

Bernstein, M H; Hudson, D M; Stearns, J M; Hoyt, R W

1977-08-01

208

Epiphyte Water Retention and Evaporation in Native and Invaded Tropical Montane Cloud Forests in Hawaii  

NASA Astrophysics Data System (ADS)

Epiphyte water retention was quantified at two montane cloud forest sites in Hawai'i Volcanoes National Park, one native and the other invaded by an alien tree species. Water storage elements measured included all epiphytic mosses, leafy liverworts, and filmy ferns. Tree surface area was estimated and a careful survey was taken to account for all epiphytes in the sample area of the forest. Samples were collected and analyzed in the lab for epiphyte water retention capacity (WRC). Based on the volume of the different kinds of epiphytes and their corresponding WRC, forest stand water retention capacity for each survey area was estimated. Evaporation from the epiphyte mass was quantified using artificial reference samples attached to trees that were weighed at intervals to determine changes in stored water on days without significant rain or fog. In addition, a soil moisture sensor was wrapped in an epiphyte sample and left in the forest for a 6-day period. Epiphyte biomass at the Native Site and Invaded Site were estimated to be 2.89 t ha-1 and 1.05 t ha-1, respectively. Average WRC at the Native Site and Invaded Site were estimated at 1.45 mm and 0.68 mm, respectively. The difference is likely due to the presence of the invasive Psidium cattleianum at the Invaded Site because its smooth stem surface is unable to support a significant epiphytic layer. The evaporation rate from the epiphyte mass near WSC for the forest stand at the Native Site was measured at 0.38 mm day-1, which represented 10.6 % of the total ET from the forest canopy at the Native Site during the period. The above research has been recently complemented by a thorough investigation of the WSC of all water storage elements (tree stems, tree leaves, shrubs, grasses, litter, fallen branches, and epiphytes) at six forested sites at different elevations within, above, and below the zone of frequent cloud-cover. The goal of this study was to create an inexpensive and efficient methodology for acquiring estimates of above-ground water retention in different types of forests by means of minimally-destructive sampling and surveying. The results of this work serve as baseline data providing a range of possible values of the water retention of specific forest elements and the entire above-ground total where no values have been previously recorded.

Mudd, R. G.; Giambelluca, T. W.

2006-12-01

209

The effects of possible future climate change on evaporation losses from four contrasting UK water catchment areas  

Microsoft Academic Search

Evaporation losses from four water catchment areas under different land uses and climatic conditions were calculated using formulations developed from small plot studies. These formulations, dependent on rainfall inputs, potential evaporation and air temperature, were extrapolated to the catchment scale using land classifications based on analysing remotely sensed imagery. The approach adopted was verified by comparing the estimated annual evaporation

Gareth Roberts

1998-01-01

210

Using water stable isotopes to assess evaporation and water residence time of lakes in EPA’s National Lakes Assessment.  

EPA Science Inventory

Stable isotopes of water (?18O and ?2H) can be very useful in large-scale monitoring programs because water samples are easy to collect and water isotopes integrate information about basic hydrological processes such as evaporation as a percentage of inflow (E/I), w...

211

Toxicity assessment of oil field produced water treated by evaporative processes to produce water to irrigation.  

PubMed

During the productive life of an oil well, a high quantity of produced water is extracted together with the oil, and it may achieve up to 99% in the end of the well's economical life. Desalination is one of mankind's earliest forms of saline water treatment, and nowadays, it is still a common process used throughout the world. A single-effect mechanical vapor compression (MVC) process was tested. This paper aims to assess the potential toxicity of produced water to be re-used in irrigation. Samples of both produced and distilled water were evaluated by 84 chemical parameters. The distilled produced water presented a reduction up to 97% for the majority of the analyzed parameters, including PAHs. Toxicity bioassays were performed with distilled produced water to evaluate the growth inhibition of Pseudokirchneriella subcapitata algae, the acute toxicity to Danio rerio fish, the germination inhibition of Lactuca sativa vegetable and the severity of toxicity, as well as behavior test with Lumbricid Earthworm Eisenia fetida. The ecotoxicological assays results showed no toxicity, indicating that the referred evaporative process can produce water to be reused in irrigation. PMID:20706017

Andrade, V T; Andrade, B G; Costa, B R S; Pereira, O A; Dezotti, M

2010-01-01

212

Evaporation of single atoms from an adsorbate island or a step to a terrace: Evaporation rate and the underlying atomic-level mechanism  

NASA Astrophysics Data System (ADS)

We examine the kinetics of atom ``evaporation'' from an adsorbate island onto the surrounding single-crystal surface. In our model the atoms forming the island move on a square lattice with rate constants qualitatively consistent with the values found for metal-on-metal systems. At the temperatures of interest here the rates are such that only atoms having no neighbors along the island's edge can evaporate. The rate constant of this elementary evaporation step is denoted by ke. Our simulations show that an atom leaves an N-particle island at a time t with a probability proportional to exp[-kNt]. The rate constant kN is determined by simulations and has several very interesting properties. (1) It depends on temperature according to the Arrhenius formula, but with an activation energy that is substantially higher than that of ke. (2) The rate constants kN and ke are connected through kN/ke=, where is the mean number of single edge atoms per island. (3) In most cases one can use for in this relationship a value calculated from an equilibrium ensemble; this leads to a very efficient method for calculating kN. (4) The size dependence of kN is unexpected: we find that kN is proportional to N0.36 for all temperatures, and for several values of ke. These findings provide insights into the statistical properties of evaporation and also lead to a substantial simplification of simulations of particle transport between islands; rather than simulate all atomic events in detail, one can perform preliminary calculations to obtain the evaporation rates kN, for all the island sizes N of interest, and then use these rates to simulate the atom exchange kinetics.

Shao, Hongxiao; Weakliem, Paul C.; Metiu, Horia

1996-06-01

213

The Rate of Unsteady-State Evaporation of a Quiescent Liquid Layer in the Open and Closed Systems  

Microsoft Academic Search

The influence of natural convection on the unsteady-state evaporation rate is analyzed theoretically on the basis of Fick's law. The observed and calculated data for propyl acetate, propyl formate, methyl acetate, and methyl formate evaporation in nitrogen are in satisfactory agreement.

V. V. Dil'man; V. A. Lotkhov; D. I. Vasilevskii

2001-01-01

214

Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity.  

National Technical Information Service (NTIS)

The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent he...

D. L. Dietrich F. A. Williams M. C. Hicks V. Nayagam

2012-01-01

215

Evaporation from porous media in the presence of a water table  

NASA Astrophysics Data System (ADS)

Improved understanding of soil evaporation in presence of a water table is important in many hydrological processes such as analysis of water and energy balance at land surface, and soil salinization. During evaporation, liquid water is transported from water table toward the surface by capillary forces opposed by the downward gravity and viscous forces. In presence of a shallow water table, the capillary forces may be strong enough to maintain liquid continuity extending from water table to the surface where the liquid vaporization occurs. However, when the water table depth is deep, capillary forces may not be able to overcome the resistive forces resulting in interruption of the liquid continuity. In such cases, using hydraulic conductivity and Richard’s equation across the entire soil profile to estimate the evaporative flux causes overlooking the physical mechanisms governing the process, though good agreements might be obtained by applying some fitting parameters in unsaturated hydraulic conductivity to match the prediction with the experimental data. The main objective of the present study is to enhance the awareness of limitation of rather automatic assumption of hydraulic continuity through unsaturated zone across large distances above the water table. We used the concept of evaporation characteristic lengths to predict the maximum height of liquid continuity above the water table. When the depth of water table exceeds this characteristic length deduced from the pore size distribution, the hydraulic connection with surface is interrupted resulting in considerable suppression of evaporation due to the evolution of vaporization plane from the surface to a level below the surface defined by the maximum height of the liquid continuity above the water table. To test this model, laboratory evaporation experiments were conducted using Plexiglas columns (600 mm in height and 70 mm in diameter) packed with sand initially saturated with water exposed to evaporation from top boundary. For water supply, Mariotte bottles mounted on digital balances were connected to the bottom of the columns. We used three types of sand differing in particle size distribution. To maintain constant levels of water table, Mariotte bottles were fixed at different depths below the sand surface. The mass loss from the columns and relative humidity and temperature above the columns were recorded digitally each five minutes for nearly 500 hours. Our results confirmed the critical role of liquid continuity above the water table on the evaporative water losses from porous media. The predicted maximum water table depths marking the transition from atmospheric-limited fluxes to the much lower fluxes limited by the transport properties of the porous medium were in good agreement with the experimental results. In addition to the detailed analysis of the relation between water table depths and evaporative water losses, our results provide new insights regarding solute transports and deposition patterns affected by the depth of water table during evaporation.

Shokri, N.; Salvucci, G.

2010-12-01

216

A general method of parameterizing the big-leaf model to predict the dry-canopy evaporation rate of individual coniferous forest stands  

NASA Astrophysics Data System (ADS)

This study proposes a general method of parameterizing the big-leaf model that is applicable to estimation of daytime dry-canopy evaporation (hereafter, evaporation) rates of coniferous forest stands without observed flux data. The method considers variation in the reference value of surface conductance Gs between individual stands by incorporating a relationship between canopy height and reference Gs values reported by Komatsu (2003c) [Hydrological Processes 17: 2503-2512]. However, the method does not consider variation in modifier functions of Gs and in aerodynamic conductance Ga between individual stands. We examined the validity of the method based on daytime evaporation rate data for 26 coniferous stands. The method showed greater predictability than another method that ignores variation in reference Gs values between individual stands. This illustrates the validity of considering variation in reference Gs values between individual stands. Model predictability was not enhanced by considering variation in modifier functions of Gs and Ga between individual stands. This illustrates the validity of ignoring variation in modifier functions of Gs and Ga between individual stands. The method is applicable to stands with projected LAI ? 3.0 and canopy height evaporation rates of coniferous stands, as many stands fall within these limitations. The method is applicable to evaporation rate estimates in growing seasons without soil water stress when dry-canopy evaporation significantly affects the forest water cycle. At this stage, the method can result in errors when applied outside this limitation. However, the method should be valuable as a basis for developing a more comprehensive method applicable outside this limitation.

Komatsu, Hikaru

2004-11-01

217

Radiator/water evaporator heat rejection system for an advanced extravehicular mobility unit  

NASA Astrophysics Data System (ADS)

A study is being conducted on the design, development, fabrication, integration, and testing of subsystems for an advanced extravehicular mobility unit portable life support system for evolutionary Space Station Freedom or other applications. The subsystem discussed in this paper is the heat rejection system (HRS). The function of the HRS is to remove metabolic and equipment heat loads and provide a comfortable thermal environment for a crewperson during extravehicular activity. The HRS comprises a radiator and a water evaporator. Use of this HRS results in the venting of the evaporated water. This combination of components, however, offers a significant reduction in water usage compared to a standalone evaporator or sublimator, and a significant reduction in weight compared to nonventing configurations.

Strumpf, Hal J.; Vuigner, A. A.

1992-07-01

218

Witnessing Evaporation  

NSDL National Science Digital Library

The engineers at Splash Engineering (the students) have been commissioned by Thirsty County to conduct a study of evaporation and transpiration in their region. During one week, students observe and measure (by weight) the ongoing evaporation of water in pans set up with different variables, and then assess what factors may affect evaporation. Variables include adding to the water an amount of soil and an amount of soil with growing plants.

Integrated Teaching And Learning Program

219

Mass Transfer and Thermodynamic Studies of Evaporative Freezing of Water.  

National Technical Information Service (NTIS)

Some of the key technical problems inherent in the design of equipment for the absorption, freezing, vapor-compression process for the production of pure water from salt water were investigated in laboratory studies. These included the comparison of vario...

R. L. Pigford

1983-01-01

220

Non-isothermal soil water transport and evaporation  

Microsoft Academic Search

A detailed model was formulated to describe the non-isothermal transport of water in the unsaturated soil zone. The model consists of the coupled equations of mass conservation for the liquid phase, gas phase and water vapor and the energy conservation equation. The water transport mechanisms considered are convection in the liquid phase, and convection, diffusion and dispersion of vapor in

Jordi Grifoll; Josep Ma. Gastoa; Yoram Cohen

2005-01-01

221

Operation of a low temperature absorption chiller at rating point and at reduced evaporator temperature  

NASA Astrophysics Data System (ADS)

The returned fifteen ton Solar Absorption Machine (SAM) 015 chiller was given a cursory visual inspection, some obvious problems were remedied, and then it was placed on a test stand to get a measure of dirty performance. It was then given a standard acid clean, the water side of the tubes was brushed clean, and then the machine was retested. The before and after cleaning data were compared to equivalent data taken before the machine was shipped. The second part of the work statement was to experimentally demonstrate the technical feasibility of operating the chiller at evaporator temperatures below 0(0)C (32(0)F) and identify any operational problems.

Best, R.; Biermann, W.; Reimann, R. C.

1985-01-01

222

Leaf growth and turgor in growing cells of maize (Zea mays L.) respond to evaporative demand under moderate irrigation but not in water-saturated soil.  

PubMed

To test whether the inhibition of leaf expansion by high evaporative demand is a result of hydraulic processes, we have followed both leaf elongation rate (LER) and cell turgor in leaves of maize plants either normally watered or in water-saturated soil in which hydraulic resistance at the soil-root interface was abolished. Cell turgor was measured in situ with a pressure probe in the elongating zone of the first and sixth leaves, and LERs of the same leaves were measured continuously with transducers or by following displacements of marks along the growing leaves. Both variables displayed spatial variations along the leaf and positively correlated within the elongating zone. Values peaked at mid-distance of this zone, where the response of turgor to evaporative demand was further dissected. High evaporative demand decreased both LER and turgor for at least 5 h, with dose-effect linear relations. This was observed in five genotypes with appreciable differences in turgor maintenance among genotypes. In contrast, the depressing effects of evaporative demand on both turgor and LER disappeared when the soil was saturated, thereby opposing a negligible resistance to water flow at the soil-root interface. These results suggest that the response of LER to evaporative demand has a hydraulic origin, enhanced by the resistance to water flux at the soil-root interface. They also suggest that turgor is not completely maintained under high evaporative demand, and may therefore contribute to the reductions in LER observed in non-saturated soils. PMID:17080939

Bouchabké, Oumaya; Tardieu, François; Simonneau, Thierry

2006-06-01

223

Does evaporation paradox exist in China?  

Microsoft Academic Search

One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called the evaporation paradox. Based on data from 317 weather stations in China from

Z. T. Cong; D. W. Yang

2008-01-01

224

A Study of the Velocity Field during Evaporation of Sessile Water and Water\\/Ethanol Drops  

Microsoft Academic Search

Many studies have investigated evaporation of sessile drops in an attempt to understand the effect of wetting on the evaporation process. Recently interest has also increased in the deposition of particles from such drops, with evaporative mass flux being deemed to be responsible for ring-like deposits, and counteraction of the mass flux by Marangoni convection explaining more uniform deposition patterns.

John R. E. Christy; Khellil Sefiane; Euan Munro

2010-01-01

225

Experimental investigation on the characteristics of flash evaporation from superheated water jets for desalination  

Microsoft Academic Search

A promising method of desalination suitable for low-populated islands and remote areas is experimentally investigated at a small desalination plant capable of producing 15.2tons of fresh water per day based on the flash evaporation from superheated water jets. In this method, water at a temperature ranging from 24 to 40°C is brought to superheat condition through the injection into a

Sami Mutair; Yasuyuki Ikegami

2010-01-01

226

PMMA microcapsules containing water-soluble dyes obtained by double emulsion\\/solvent evaporation technique  

Microsoft Academic Search

Summary  \\u000a The aim of this study was to prepare microcaspules containing a water-soluble dye used in textile industry. These microcapsules\\u000a must be stable during the time and no release of the dye must be observed during their stocking. The difficulty of this work\\u000a lies in the water-solubility of the dye which does not allow a classical oil-in-water solvent evaporation and

N. Zydowicz; E. Nzimba-Ganyanad

2002-01-01

227

New limit on the rate-density of evaporating black holes  

NASA Astrophysics Data System (ADS)

Data taken with the CYGNUS detector between 1989 September and 1993 January have been used to search for 1 s bursts of ultrahigh-energy gamma rays from point sources at arbitrary locations in the northern sky. We find no evidence for such bursts. We set a theory-dependent upper limit on the rate-density of evaporating black holes of 8.5×105 pc-3 yr-1 at the 99% C.L. When the same emission spectrum is used to recalculate previous upper limits based on direct searches, this limit is the most restrictive by nearly 2 orders of magnitude.

Alexandreas, D. E.; Allen, G. E.; Berley, D.; Biller, S.; Burman, R. L.; Cavalli-Sforza, M.; Chang, C. Y.; Chen, M. L.; Chumney, P.; Coyne, D.; Dion, C.; Dion, G. M.; Dorfan, D.; Ellsworth, R. W.; Goodman, J. A.; Haines, T. J.; Harmon, M.; Hoffman, C. M.; Kelley, L.; Klein, S.; Nagle, D. E.; Schmidt, D. M.; Schnee, R.; Sinnis, C.; Shoup, A.; Stark, M. J.; Weeks, D. D.; Williams, D. A.; Wu, J. P.; Yang, T.; Yodh, G. B.; Zhang, W. P.

1993-10-01

228

A New Limit on the Rate-Density of Evaporating Black Holes  

NASA Astrophysics Data System (ADS)

Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1times 10(5) pc(-3}yr({-1)) at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude.

Coyne, D.; Biller, S.; Chumney, P.; Harmon, M.; Shoup, A.; Yodh, G. B.; Alexandreas, D. E.; Allen, G. E.; Chang, C. Y.; Chen, M. L.; Dion, C.; Goodman, J. A.; Haines, T. J.; Stark, M. J.; Dion, G. M.; Berley, D.; Burman, R. L.; Hoffman, C. M.; Nagle, D. E.; Schmidt, D. M.; Sinnis, C.; Weeks, D. D.; Zhang, W. P.; Ellsworth, R. W.; Cavalli-Sforza, M.; Coyne, D.; Dorfan, D.; Kelley, L.; Klein, S.; Schnee, R.; Williams, D. A.; Yang, T.; Wu, J.-P.

1993-05-01

229

A new limit on the rate-density of evaporating black holes  

SciTech Connect

Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1 {times} 10{sup 5}pc{sup {minus}3}yr{sup {minus}1} at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude.

The CYGNUS Collaboration

1993-05-01

230

A new limit on the rate-density of evaporating black holes  

SciTech Connect

Data taken with the CYGNUS detector between 1989 and 1993 have been used to search for 1 second bursts of ultra-high energy (UHE) gamma rays from any point in the northern sky. There is no evidence for such bursts. Therefore the theory-dependent upper limit on the rate-density of evaporating black holes is 6.1 [times] 10[sup 5]pc[sup [minus]3]yr[sup [minus]1] at the 99% C.L.. After renormalizing previous direct searches to the same theory, this limit is the most restrictive by more than 2 orders of magnitude.

Not Available

1993-01-01

231

Controlling Dopant Profiles in Hyperdoped Silicon by Modifying Dopant Evaporation Rates During Pulsed Laser Melting  

SciTech Connect

We describe a method to control the sub-surface dopant profile in 'hyperdoped' silicon fabricated by ion implantation and pulsed laser melting. Dipping silicon ion implanted with sulfur into hydrofluoric acid prior to nanosecond pulsed laser melting leads to a tenfold increase in the rate of sulfur evaporation from the surface of the melt. This results in an 80% reduction of the near-surface dopant concentration, effectively embedding the hyperdoped region in a layer up to 180 nm beneath the surface. This method should facilitate the development of blocked impurity band devices.

Recht, D.; Sullivan, J. T.; Reedy, R.; Buonassisi, T.; Aziz, M. J.

2012-03-12

232

Controlling dopant profiles in hyperdoped silicon by modifying dopant evaporation rates during pulsed laser melting  

NASA Astrophysics Data System (ADS)

We describe a method to control the sub-surface dopant profile in ``hyperdoped'' silicon fabricated by ion implantation and pulsed laser melting. Dipping silicon ion implanted with sulfur into hydrofluoric acid prior to nanosecond pulsed laser melting leads to a tenfold increase in the rate of sulfur evaporation from the surface of the melt. This results in an 80% reduction of the near-surface dopant concentration, effectively embedding the hyperdoped region in a layer up to 180 nm beneath the surface. This method should facilitate the development of blocked impurity band devices.

Recht, Daniel; Sullivan, Joseph T.; Reedy, Robert; Buonassisi, Tonio; Aziz, Michael J.

2012-03-01

233

FIELD DEPLOYMENT EVALUATION OF THE FREEZE-THAW/EVAPORATION (FTE) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS. Task 45. Final topical report.  

National Technical Information Service (NTIS)

TASK 45 FIELD DEPLOYMENT EVALUATION OF THE FREEZE THAW/ EVAPORATION (FTE ) PROCESS TO TREAT OIL AND GAS PRODUCED WATERS coupling evaporation with freezing. This offers operators a year- round method for treating produced water. Treating water with the FTE...

A. A. Grisanti J. A. Sorensen

1999-01-01

234

The isotopic composition of evaporating waters - review of the historical evolution leading up to the Craig-Gordon model.  

PubMed

Attempts to explain the variations in the abundance of heavy isotopic species of water throughout the hydrologic cycle solely by means of the classical equilibrium-fractionation processes could not be reconciled with measured abundances of the isotopic species in residues of "evaporation systems". Focusing on the evaporation of surface waters, the paper follows the evolution of the concepts during the 1950-ties and early 1960-ties leading up to the formulation of the Craig-Gordan Evaporation Model in 1965. PMID:18320424

Gat, Joel R

2008-03-01

235

Climate Processes of Lake Evaporation and Snowmelt Runoff: Part I. Evaporation Rates from Temperature-Stratified Saline - Lake as a Case Study. Part II. Snowmelt Runoff and Climate - Lake Basin as a Case Study  

NASA Astrophysics Data System (ADS)

In part I, a methodology for determining the evaporation rates from temperature-stratified saline lakes has been developed. The initial motivation was to develop a technique which would be more accurate than the widely used evaporation pan method, and which would use meteorological data inputs that are normally available at weather stations, or are otherwise easy and inexpensive to gather. Four functional modules are combined in the model: a modified mass transfer function, a simulated solar radiation function, a simulated surface energy balance function, and simulated water thermocline function. The outputs of the model are the lake evaporation rate and the lake water temperature. In this study, the model is validated and applied to Mono Lake to simulate saline water evaporation rates. The results compared favorably with results of other saline water evaporation studies, both in economy and accuracy. In part II, an energy-, momentum-, and mass-balanced snowmelt runoff model was developed to study an alpine watershed with an elevation of 3000 m in the Sequoia National Forest, California. The methodology successfully simulates the snow water equivalent and the daily snowmelt runoff. The benefits of this model are reduction in both data requirement and computer time. Only meteorologic data are required in this model. In order to develop a computationally efficient code, this snowmelt runoff model is discretized into two layers only. This model is at least 20 times faster than Anderson's (1976) model. Furthermore, an attempt to determine snowmelt runoff from a watershed by using the developed energy-based model is conducted. The preliminary results are excellent. Snowmelt runoff processes in an alpine watershed in the Sequoia National Forest under long-term global warming are analyzed using the above energy based snowmelt runoff model. Under global warming, although there might be more precipitation, the hydrograph of snowmelt runoff would shift between 19 and 93 days earlier and snow season would end between 25 and 68 days earlier at an elevation of 2800 m. The most striking change would be the dramatic decrease in the snow/precipitation ratio at elevations below 2300 m, where the ecological balance would suffer a major impact.

Tsuang, Ben Jei

236

Urban Signatures: Evaporation (WMS)  

NSDL National Science Digital Library

Big cities influence the environment around them. For example, urban areas are typically warmer than their surroundings. Cities are strikingly visible in computer models that simulate the Earths land surface. This visualization shows evaporation rates predicted by the Land Information System (LIS) for a day in June 2001. Evaporation is lower in the cities because water tends to run off pavement and into drains, rather than being absorbed by soil and plants from which it later evaporates. Only part of the global computation is shown, focusing on the highly urbanized northeast corridor in the United States, including the cities of Boston, New York, Philadelphia, Baltimore, and Washington.

Delabeaujardiere, Jeff

2005-05-27

237

Evaporation from three water bodies of different sizes and climates: Measurements and scaling analysis  

Microsoft Academic Search

Evaporation from small reservoirs, wetlands, and lakes continues to be a theoretical and practical problem in surface hydrology and micrometeorology because atmospheric flows above such systems can rarely be approximated as stationary and planar-homogeneous with no mean subsidence (hereafter referred to as idealized flow state). Here, the turbulence statistics of temperature (T) and water vapor (q) most pertinent to lake

S. Assouline; S. W. Tyler; J. Tanny; S. Cohen; E. Bou-Zeid; M. B. Parlange; G. G. Katul

2008-01-01

238

Development of an Evaporation Prediction Model for Open Water Bodies of South Carolina and Similar Regions.  

National Technical Information Service (NTIS)

The purpose of this study is to upgrade the predictive capability for evaporation in South Carolina and in similar geographical regions and to present the results in a manner which can be used for water resource planning. The final product is a menu-drive...

J. L. Reck W. T. Robinson B. L. Sill

1995-01-01

239

EFFECT OF HYDROPHILIC ZEIN FILMS ON THE GROWTH OF TOMATO PLANTS AND EVAPORATIVE WATER LOSS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of ground cover films prepared from zein on the growth of tomato plants and corresponding evaporative water loss was investigated in greenhouse experiments. Zein is an alcohol soluble protein isolated from corn. Films were prepared both from an experimental zein isolate (a zein-lipid mi...

240

EFFECT OF HYDROPHILIC ZEIN FILMS ON THE GROWTH OF TOMATO PLANTS AND EVAPORATIVE WATER LOSS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Non-biodegradable, polymeric materials presently used as ground cover to control weeds and contain or reduce water evaporation are inexpensive to manufacture but expensive to use because of additional cost in collecting the material after the growing season. In addition, polymer materials, which can...

241

Monitoring near surface soil water and associated dynamics of infiltration and evaporation fluxes  

Technology Transfer Automated Retrieval System (TEKTRAN)

In-situ monitoring of soil water has the advantage of integrating the precipitation and evaporation history and gradual changes in hydraulic properties on the aggregate response of the soil-plant-atmosphere system. A paired field study in Bushland, Texas, and Tribune, Kansas, evaluated infiltration ...

242

PROCESS WATER BUILDING, TRA605. ONE OF THREE EVAPORATORS BEFORE IT ...  

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

PROCESS WATER BUILDING, TRA-605. ONE OF THREE EVAPORATORS BEFORE IT IS INSTALLED IN UPPER LEVEL OF EAST HALF OF BUILDING. INL NEGATIVE NO. 1533. Unknown Photographer, 3/1/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

243

PROCESS WATER BUILDING, TRA605. FLASH EVAPORATORS ARE PLACED ON UPPER ...  

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

PROCESS WATER BUILDING, TRA-605. FLASH EVAPORATORS ARE PLACED ON UPPER LEVEL OF EAST SIDE OF BUILDING. WALLS WILL BE FORMED AROUND THEM. WORKING RESERVOIR BEYOND. CAMERA FACING EASTERLY. EXHAUST AIR STACK IS UNDER CONSTRUCTION AT RIGHT OF VIEW. INL NEGATIVE NO. 2579. Unknown Photographer, 6/18/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

244

Expanding the Bioheat Equation to Include Tissue Internal Water Evaporation During Heating  

Microsoft Academic Search

We propose a new method to study high temperature tissue ablation using an expanded bioheat diffusion equation. An extra term added to the bioheat equation is combined with the specific heat into an effective (temperature dependent) specific heat. It replaces the normal specific heat term in the modified bioheat equation, which can then be used at temperatures where water evaporation

Deshan Yang; Mark C. Converse; David M. Mahvi; John G. Webster

2007-01-01

245

Salt-Formation by Progressive Evaporation of Brine Waters in the Endurance Crater Basin at Meridiani  

NASA Astrophysics Data System (ADS)

The sulfate/chloride vs. Cl and chloride/bromide vs. Br relationships in the salt-assemblages on Meridiani (RAT) rock-rinds indicate that these salts likely formed by progressive evaporative concentration of brine waters filling the Endurance Crater basin

Rao, M. N.; Nyquist, L. E.; Wentworth, S. J.; Garrison, D. H.; Herrin, J. S.

2007-03-01

246

RELATIONSHIP BETWEEN A SOLAR DRYING MODEL OF RED PEPPER AND THE KINETICS OF PURE WATER EVAPORATION (I)  

Microsoft Academic Search

Drying of red pepper under solar radiation was investigated, and a simple model related to water evaporation was developed. Drying experiments at constant laboratory conditions were undertaken where solar radiation was simulated by a 1000 W lamp.In this first part of the work, water evaporation under radiation is studied and laboratory experiments are presented with two objectives: to verify Penman's

Victor Passamai; Luis Saravia

1997-01-01

247

The hydrogen and oxygen isotopic composition of precipitation, evaporated mine water, and river water in Montana, USA  

NASA Astrophysics Data System (ADS)

The isotopic composition of 42 samples of rain and snow collected in 2004 were used to construct a local meteoric water line (LMWL) for Butte, Montana. The derived equation (?D = 7.31?18O - 7.5, r2 = 0.987), represents one of the first published LMWLs based on direct precipitation for any location in the northern Rocky Mountains. Samples of underground and surface mine waters in Butte, including the Berkeley pit-lake and a nearby tailings pond, define a linear trend with a much lower slope and intercept than the LMWL (?D = 5.00?18O - 49.5, r2 = 0.991), consistent with non-equilibrium evaporation at an average relative humidity of roughly 65%. Detailed evaporation calculations are presented which indicate that the shallow Berkeley pit-lake was approximately 25% evaporated in October, 2003, whereas the surface of the tailings pond was at least 50% evaporated. The intersection of the LMWL and mine water evaporation trend was used to calculate the average composition of recharge water to the flooded mine complex (?D = -139‰, ?18O = -18.0‰). These values are considerably lighter than the weighted total of precipitation for the 2004 calendar year (?D = -118‰, ?18O = -15.3‰), which is partly explained by the unusually low snowfall that Montana experienced in 2004. Based on this study, the LMWL recently proposed by Kendall and Coplen (2001) [Kendall, C., Coplen, T.B., 2001. Distribution of oxygen-18 and deuterium in river waters across the United States, Hydrological Processes 15, 1363 1393] from regression of isotopic data from a number of Montana rivers is more accurately interpreted as an evaporation line. Isotopic trends based on river data should be treated with caution, particularly in a semi-arid region such as Montana where rivers are often influenced by dams and irrigation withdrawals.

Gammons, Christopher H.; Poulson, Simon R.; Pellicori, Damon A.; Reed, Pamela J.; Roesler, Amber J.; Petrescu, Eugene M.

2006-08-01

248

Isotope effects in the evaporation of water: a status report of the Craig–Gordon model  

Microsoft Academic Search

The Craig–Gordon model (C–G model) [H. Craig, L.I. Gordon. Deuterium and oxygen 18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperatures, E. Tongiorgi (Ed.), pp. 9–130, Laboratorio di Geologia Nucleare, Pisa (1965).] has been synonymous with the isotope effects associated with the evaporation of water from surface waters, soils, and vegetations, which

Juske Horita; Kazimierz Rozanski; Shabtai Cohen

2008-01-01

249

Isotope Effects in the Evaporation of Water: A Status report of the Craig - Gordon Model  

SciTech Connect

The Craig-Gordon model (C-G model) has been synonymous with the isotope effects associated with the evaporation of water from surface waters, soils, and vegetations, which in turn constitutes a critical component of the global water cycle. On the occasion of the four decades of its successful applications to isotope geochemistry and hydrology, an attempt is made to: (a) examine its physical background within the framework of modern evaporation models, (b) evaluate our current knowledge of the environmental parameters of the C-G model, and (c) comment on a general strategy for the use of these parameters in field applications. Despite its simplistic representation of evaporation processes at the water-air interface, the C-G model appears to be adequate to provide the isotopic composition of the evaporation flux. This is largely due to its nature for representing isotopic compositions (a ratio of two fluxes of different isotopic water molecules) under the same environmental conditions. Among many environmental parameters that are included in the C-G model, accurate description and calculations are still problematic of the kinetic isotope effects that occur in a diffusion-dominated thin layer of air next to the water-air interface. In field applications, it is of importance to accurately evaluate several environmental parameters, particularly the relative humidity and isotopic compositions of the 'free-atmosphere', for a system under investigation over a given time-scale of interest (e.g., hourly to daily to seasonally). With a growing interest in the studies of water cycles of different spatial and temporal scales, including paleoclimate and water resource studies, the importance and utility of the C-G model is also likely to grow in the future.

Horita, Juske [ORNL; Rozanski, K. [AGH University of Science and Technology, Krakow, Poland; Cohen, S. [Volcani Center, Agricultural Research Organization, Bet Dagan Israel

2008-01-01

250

Isotope effects in the evaporation of water: a status report of the Craig-Gordon model.  

PubMed

The Craig-Gordon model (C-G model) [H. Craig, L.I. Gordon. Deuterium and oxygen 18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperatures, E. Tongiorgi (Ed.), pp. 9-130, Laboratorio di Geologia Nucleare, Pisa (1965).] has been synonymous with the isotope effects associated with the evaporation of water from surface waters, soils, and vegetations, which in turn constitutes a critical component of the global water cycle. On the occasion of the four decades of its successful applications to isotope geochemistry and hydrology, an attempt is made to: (a) examine its physical background within the framework of modern evaporation models, (b) evaluate our current knowledge of the environmental parameters of the C-G model, and (c) comment on a general strategy for the use of these parameters in field applications. Despite its simplistic representation of evaporation processes at the water-air interface, the C-G model appears to be adequate to provide the isotopic composition of the evaporation flux. This is largely due to its nature for representing isotopic compositions (a ratio of two fluxes of different isotopic water molecules) under the same environmental conditions. Among many environmental parameters that are included in the C-G model, accurate description and calculations are still problematic of the kinetic isotope effects that occur in a diffusion-dominated thin layer of air next to the water-air interface. In field applications, it is of importance to accurately evaluate several environmental parameters, particularly the relative humidity and isotopic compositions of the 'free-atmosphere', for a system under investigation over a given time-scale of interest (e.g., hourly to daily to seasonally). With a growing interest in the studies of water cycles of different spatial and temporal scales, including paleoclimate and water resource studies, the importance and utility of the C-G model is also likely to grow in the future. PMID:18320426

Horita, Juske; Rozanski, Kazimierz; Cohen, Shabtai

2008-03-01

251

Evaporation and wetting dynamics of sessile water droplets on submicron-scale patterned silicon hydrophobic surfaces  

SciTech Connect

The evaporation characteristics of 1 l sessile water droplets on hydrophobic surfaces are experimentally examined. The proposed hydrophobic surfaces are composed of submicron diameter and 4.2- m-height silicon post arrays. A digital image analysis algorithm was developed to obtain time-dependent contact angles, contact diameters, and center heights for both non-patterned polydimethylsiloxane (PDMS) surfaces and patterned post array surfaces, which have the same hydrophobic contact angles. While the contact angles exhibit three distinct stages during evaporation in the non-patterned surface case, those in the patterned silicon post array surface case decrease linearly. In the case of post array hydrophobic surfaces, the initial contact diameter remains unchanged until the portion of the droplet above the posts completely dries out. The edge shrinking velocity of the droplet shows nonlinear characteristics, and the velocity magnitude increases rapidly near the last stage of evaporation.

Choi, Chang Kyoung [Michigan Technological University; Shin, Dong Hwan [Chung-Ang University; Lee, Seong Hyuk [Chung-Ang University; Retterer, Scott T [ORNL

2010-01-01

252

Variable Subduction Rates of North Atlantic Salinity Maximum Water  

NASA Astrophysics Data System (ADS)

Data from programs back to 1982, and most recently the 2003-04 Repeat Hydrography, Tracer, CO2 program are used to highlight the role tracer data can have in monitoring decadal variability of ocean circulation. The CFC data are used to document changes in thermocline ventilation, and specifically the affect increased thermocline salinity is having, if any, on Salinity Maximum Water (SMW) subduction rates in the North Atlantic Ocean. Hydrobase data show a long term trend of increasing salinity in the North Atlantic thermocline since the 1950s, and in particular in SMW. SMW is located in the subtropical/tropical north Atlantic under the evaporation minus precipitation maximum. Since SMW are the most saline of the thermocline waters, no source for additional salt exists within the ocean. Subduction rates have been calculated for SMW from 1982-2004 CFC data at stations where there was a subsurface salinity maximum present. The subduction rate for an isopycnal projected back to its outcrop, is calculated from the inverse tracer age gradient corrected for vortex stretching. Subduction rates vary from 10 to 40 m/year. The results show a pattern of changing subduction rates that correlate well with the NAO index. Since salinity seems to have been steadily increasing, though at different rates, it appears that local fresh water variability is not the major forcing effect on the subduction process. The 1990s rise in evaporation rate coincided with a prolonged high state of the North Atlantic Oscillation index (NAO). The associated increase in trade winds will have enhanced both evaporation and Ekman pumping of waters into the upper ventilated thermocline. Consistent with model results, the observational based calculations suggest that increased (decreased) wind stress curl accompanying an increased (decreased) NAO has the major forcing effect on SMW subduction variability.

Fine, R. A.; Willey, D. A.; Happell, J.

2004-12-01

253

Laboratory Prototype Flash Evaporator.  

National Technical Information Service (NTIS)

A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and ...

J. L. Gaddis

1972-01-01

254

Effects of crop residue on soil and plant water evaporation in a dryland cotton system  

NASA Astrophysics Data System (ADS)

Dryland agricultural cropping systems emphasize sustaining crop yields with limited use of fertilizer while conserving both rain water and the soil. Conservation of these resources may be achieved with management systems that retain residues at the soil surface simultaneously modifying both its energy and water balance. A conservation practice used with cotton grown on erodible soils of the Texas High Plains is to plant cotton into chemically terminated wheat residues. In this study, the partitioning of daily and seasonal evapotranspiration ( E t) into soil and plant water evaporation was compared for a conventional and a terminated-wheat cotton crop using the numerical model ENWATBAL. The model was configured to account for the effects of residue on the radiative fluxes and by introducing an additional resistance to latent and sensible heat fluxes derived from measurements of wind speed and vapor conductance from a soil covered with wheat-stubble. Our results showed that seasonal E t was similar in both systems and that cumulative soil water evaporation was 50% of E t in conventional cotton and 31% of E t in the wheat-stubble cotton. Calculated values of E t were in agreement with measured values. The main benefit of the wheat residues was to suppress soil water evaporation by intercepting irradiance early in the growing season when the crop leaf area index (LAI) was low. In semiarid regions LAI of dryland cotton seldom exceeds 2 and residues can improve water conservation. Measured soil temperatures showed that early in the season residues reduced temperature at 0.1 m depth by as much as 5°C and that differences between systems diminished with depth and over time. Residues increased lint yield per unit of E t while not modifying seasonal E t and reducing cumulative soil water evaporation.

Lascano, R. J.; Baumhardt, R. L.

1996-03-01

255

Evaporation and Infiltration from Water Bodies in the Lerma-Chapala Basin, Mexico  

NASA Astrophysics Data System (ADS)

Reservoirs and ponds significantly influence the hydrology of the Lerma-Chapala river basin in Mexico and affect inflows to the receiving waters of Lake Chapala. This paper reports on remote sensing and GIS assessment of the 55,511 km2 basin, in which 81 lakes and reservoirs, and 28,895 ponds were identified from post-rainy season 1998 Thematic Mapper imagery. Digital terrain analysis coupled with sedimentation estimates from soil and land cover data were used to estimate impounded volumes in ponds, and in reservoirs for which storage data were unreported. Open water surface evaporation (3.2 - 7.4 mm/day) was determined using a surface energy balance model, Penman-Monteith, and corrected pan evaporation methods. Sediment samples were analyzed, and a pedo-transfer function was used to estimate saturated hydraulic conductivity (0.2 - 6.6 mm/day) of the bed sediments, which are assumed to be the layer that limits percolation recharge to groundwater. The ponds' shallow depths and sediments with high clay and low organic matter contents result in evaporation to infiltration ratios of approximately 2:1 over the dry season. Increasing irrigation from ponds or permitting this water to flow downstream to deeper reservoirs may result in less water loss than allowing impounded water to recharge and subsequently withdrawing groundwater.

Scott, C. A.; Flores-Lopez, F. F.

2001-05-01

256

Homogeneous nucleation rates for water  

NASA Astrophysics Data System (ADS)

Homogeneous nucleation rates of light (H2O) and heavy (D2O) water have been measured under identical conditions. Comparing the nucleation rates for H2O and D2O at the same respective vapor pressure pv and temperature T the rates differ by a factor of 2500. However, the individual data points superimpose, if compared at the same supersaturation, i.e., they are the same within experimental scatter. Onset supersaturations S0 for H2O at nucleation rates of J0=107 cm-3 s-1 compared with previous measurements by Viisanen et al.(Viisanen, Y., Strey, R., and Reiss, H., J. Chem. Phys., 99, 4680 (1993); Erratum: Viisanen, Y., Strey, R., and Reiss, H., J. Chem. Phys., (2000) in press) show fair agreement. Predictions by the classical nucleation theory-using the most recent expressions for temperature-dependent vapor pressure, surface tension and density-are compared to the experimental data. While the predictions correctly yield the slope of the experimental nucleation rate curves and for one temperature (for H2O T=240 K) even the correct absolute rate, the temperature dependence is experimentally shown to be weaker. .

Wölk, Judith; Viisanen, Yrjö; Strey, Reinhard

2000-08-01

257

Absence of Marangoni convection at Marangoni numbers above 27,000 during water evaporation.  

PubMed

Two mechanisms by which Marangoni convection can be produced at the interface of water with its vapor are: (1) by imposing a temperature gradient parallel to the water-vapor interface, and (2) by imposing a temperature gradient perpendicular to the interface that results in the liquid becoming unstable. A series of evaporation experiments conducted with H2O and with D2O maintained at the mouth of a stainless-steel funnel indicated the presence of Marangoni convection, but the mechanism producing the convection was unclear. We have investigated the mechanism using a funnel constructed with a polymethyl methacrylate that has a small thermal conductivity relative to that of water and repeating the evaporation experiments. Marangoni convection was eliminated with this funnel even though the Marangoni number, Ma, was in the range 8277< or =Ma< or =27 847 . A comparison of the assumptions made in the theories available to predict the onset of Marangoni convection with the observations made in this study indicates some of the assumptions are invalid: although generally neglected, energy transport through the vapor to the interface of evaporating water is significant; there is an interfacial temperature discontinuity, but it is in the opposite direction of that assumed in the existing theories: the interfacial-vapor temperature is greater than that of the liquid during evaporation; and the prediction of the critical Marangoni number is based on an arbitrarily chosen value of the heat-transfer coefficient. When the temperature gradient is perpendicular to the water-vapor interface, these invalid assumptions indicate present theories do not apply to volatile liquids. PMID:20365074

Thompson, Ian; Duan, Fei; Ward, C A

2009-11-16

258

Absence of Marangoni convection at Marangoni numbers above 27,000 during water evaporation  

NASA Astrophysics Data System (ADS)

Two mechanisms by which Marangoni convection can be produced at the interface of water with its vapor are: (1) by imposing a temperature gradient parallel to the water-vapor interface, and (2) by imposing a temperature gradient perpendicular to the interface that results in the liquid becoming unstable. A series of evaporation experiments conducted with H2O and with D2O maintained at the mouth of a stainless-steel funnel indicated the presence of Marangoni convection, but the mechanism producing the convection was unclear. We have investigated the mechanism using a funnel constructed with a polymethyl methacrylate that has a small thermal conductivity relative to that of water and repeating the evaporation experiments. Marangoni convection was eliminated with this funnel even though the Marangoni number, Ma, was in the range 8277?Ma?27847 . A comparison of the assumptions made in the theories available to predict the onset of Marangoni convection with the observations made in this study indicates some of the assumptions are invalid: although generally neglected, energy transport through the vapor to the interface of evaporating water is significant; there is an interfacial temperature discontinuity, but it is in the opposite direction of that assumed in the existing theories: the interfacial-vapor temperature is greater than that of the liquid during evaporation; and the prediction of the critical Marangoni number is based on an arbitrarily chosen value of the heat-transfer coefficient. When the temperature gradient is perpendicular to the water-vapor interface, these invalid assumptions indicate present theories do not apply to volatile liquids.

Thompson, Ian; Duan, Fei; Ward, C. A.

2009-11-01

259

Theoretical investigation of the injection and evaporation of water in a hydrogen/oxygen steam generator  

NASA Astrophysics Data System (ADS)

For the cooling of the reaction products resulting from a stoichiometric hydrogen/oxygen combustion, water is injected normal to the gas stream. The penetration of the jet strongly influences the temperature distribution across the streaming water vapor. The penetration of the jet is calculated by using the jet shedding model. The results are compared with the data of the garden hose model. To calculate the lifetime of a water droplet in super heated stream, several models are developed. The parameters of the injection and evaporation process are varied and analyzed.

Beer, Stefan

1990-05-01

260

Characterization of the LGFSTF wind tunnel in preparation for the DOE/EPA hazardous chemical evaporation rate experiments  

SciTech Connect

The Environmental Protection Agency and the Department of Energy are conducting chemical evaporation rate experiments in the DOE`s Liquefied Gaseous Fuels Spill Test Facility (LGFSTF) wind tunnel to determine the effect on evaporation rate of pool temperature and wind speed. Evaporation rates measured in these tests will be used to verify mathematical models used to define the source (gas) rate inputs to dispersion models. In preparation for the experiments the LGFSTF tunnel has been modified to provide for the simulation of an atmospheric boundary layer flow on the tunnel floor. This report describes work performed by the DOE Modeling Support Center at the University of Arkansas to define (characterize) the turbulence properties in the boundary layer of the (modified) wind tunnel test section. Hot wire anemometry measurements were made to characterize the boundary layer flow over the evaporation test pan. Mean velocity and turbulence statistics were measured along a verticle line (extending from 0.5 cm to 60 cm above the tunnel floor) located on the tunnel centerline immediately upwind of the evaporation pan. The x-direction mean velocity data were analyzed to estimate the applicable values of the surface roughness and friction velocity for four tunnel (variable frequency controller) speed settings: 15 Hz, 30 Hz, 45 Hz, and 60 Hz.

Havens, J.; Walker, H.; Spicer, T.

1995-03-01

261

Formation of Nitrogen and Sulfur-Containing Light-Absorbing Compounds Accelerated by Evaporation of Water from Secondary Organic Aerosols  

Microsoft Academic Search

Aqueous extracts of secondary organic aerosols (SOA) generated from the ozonolysis of dlimonene were subjected to dissolution, evaporation, and re-dissolution in the presence and absence of ammonium sulfate (AS). Evaporation with AS at pH 4-9 produced chromophores that were stable with respect to hydrolysis and had a distinctive absorption band at 500 nm. Evaporation accelerated the rate of chromophore formation

Tran B. Nguyen; Paula B. Lee; Katelyn M. Updyke; David L. Bones; Julia Laskin; Alexander Laskin; Sergey Nizkorodov

2012-01-01

262

Evaporation and heating of a single suspended coal-water slurry droplet in hot gas streams  

SciTech Connect

The evaporation, heating, and burning of single coal-water slurry droplets are studied. The coal selected in this study is Pittsburgh Seam number 8 coal which is a medium volatile caking bituminous coal. The droplet is suspended on a microthermocouple and exposed to a hot gas stream. Temperature measurement and microscopic observation are performed in the parametric studies. The duration of water evaporation in CWS droplets decreases with the reduction of the droplet size, increasing of coal weight fraction, and increasing of gas temperature and velocity. The duration of heat-up is always significant due to the agglomeration. The CWS droplets are generally observed to swell like popcorn during heating. A model for the formation of the popped swelling is proposed and discussed.

Shi-chune, Y.; Liu, L.

1982-01-01

263

Using long-term water balances to parameterize surface conductances and calculate evaporation at 0.05° spatial resolution  

Microsoft Academic Search

Evaporation from the land surface, averaged over successive 8 day intervals and at 0.05° (?5 km) spatial resolution, was calculated using the Penman-Monteith (PM) energy balance equation, gridded meteorology, and a simple biophysical model for surface conductance. This conductance is a function of evaporation from the soil surface, leaf area index, absorbed photosynthetically active radiation, atmospheric water vapor pressure deficit,

Yongqiang Zhang; Ray Leuning; Lindsay B. Hutley; Jason Beringer; Ian McHugh; Jeffrey P. Walker

2010-01-01

264

Involvement of root ABA and hydraulic conductivity in the control of water relations in wheat plants exposed to increased evaporative demand  

Microsoft Academic Search

We studied the possible involvement of ABA in the control of water relations under conditions of increased evaporative demand.\\u000a Warming the air by 3°C increased stomatal conductance and raised transpiration rates of hydroponically grown Triticum durum plants while bringing about a temporary loss of relative water content (RWC) and immediate cessation of leaf extension. However,\\u000a both RWC and extension growth

Guzel Kudoyarova; Svetlana Veselova; Wolfram Hartung; Rashit Farhutdinov; Dmitry Veselov; Guzyal Sharipova

2011-01-01

265

Limited water-to-air bacterial transfer from a residential evaporative air cooler  

Microsoft Academic Search

The sump of an evaporative air cooler (EAC) artificially was contaminated with ? 106 colony-forming units (CFU) mL?1 of Micrococcus luteus, a pigmented, gram-positive, coccoid bacterium. Air in the room served by the EAC was sampled during EAC operation to detect water-to-air transfer of the test bacterium. Median indoor air concentrations of the tracer bacterium were 2.4 and 1.2 CFU

J. M. Macher; J. R. Girman; L. A. Alevantis

1995-01-01

266

Evaporative Cooling of Water in a Small Vessel Under Varying Ambient Humidity  

Microsoft Academic Search

Evaporative cooling of water in a small porous clay vessel was studied under controlled humidity conditions. In steady-state experiments performed at an ambient temperature of 23 °C, the cooling effect increased from 4.7 to 8.3 °C as the ambient relative humidity decreased from 60 to 15%. External heat and mass transfer coefficients, estimated from the steady-state measurements, were used in

Ashutosh Mittal; Tarun Kataria; Gautam K. Das; Siddharth G. Chatterjee

2006-01-01

267

DEFROSTING THE FIN TUBE EVAPORATORS OF AIR\\/WATER HEAT PUMPS USING AMBIENT AIR  

Microsoft Academic Search

Air\\/water heat pumps for heating systems are becoming increasingly popular. A major challenge for these systems is the formation of ice and frost in the fin-tube evaporator. Defrosting is usually accomplished by the reverse-cycle or hot-gas defrosting technique. In both defrosting modes, the compressor is in operation. An alternative method is ambient-air defrosting, where the heat pump's compressor is simply

B. Wellig; M. Imholz; M. Albert; K. Hilfiker

268

Effect of water vapor diffusion enhancement on soil moisture/temperature and evaporation - A numerical study  

NASA Astrophysics Data System (ADS)

Experimental and numerical studies concerning the coupled flow of liquid water and water vapor in porous media have shown differences in observed and Fickian diffusion-based modeled water vapor fluxes. Early studies explain these differences with evaporation-condensation effects in liquid islands in the variably saturated zone and enhanced water vapor flux due to local thermal gradients which differ between the different phases (air, water and solid) due to non-equilibrium effects at the pore scale. Consequently, an "enhancement factor" was introduced to correct for differences between model simulations and observations. Although widely used, recent studies question the existence of enhanced vapor diffusion because enhanced vapor-phase diffusion has never been measured or observed directly. In this contribution, we present results from numerical experiments in which we simulate coupled water and heat flow. The impact of the enhancement factor was evaluated by including or excluding it in the parameterization of the systems' properties. We designed three different model scenarios: one scenario with boundary conditions that represent field conditions and two scenarios representing different kinds of laboratory soil column experiments, to investigate under which conditions the impact of the enhancement factor could be observed in experiments. Finally, we tested with model simulations whether liquid water flow in films, which is not considered in the classical Mualem- van Genuchten parameterization of the hydraulic conductivity curve, can be an alternative explanation for larger than expected evaporation fluxes.

Steenpass, Christian; Vanderborght, Jan; Huisman, Johan Alexander

2010-05-01

269

Arsenic speciation and accumulation in evapoconcentrating waters of agricultural evaporation basins.  

PubMed

To sustain agricultural productivity, evaporation basins (or ponds) have been widely used for the disposal of agricultural drainage in areas requiring subsurface drainage in the San Joaquin Valley of California, USA. The drainage water contains elevated concentration of trace elements including selenium (Se) and arsenic (As). Unlike Se, little information is available about As, a potentially high risk element. The objective of this study was to characterize the chemical behavior of As and acquire data for better understanding of biogeochemical processes and conditions affecting As fate in evaporation ponds. The study site was a 726 ha evaporation basin facility (containing 10 cells with water flowing in series) in the hydrologically closed Tulare Basin of California. We examined water chemistry, As concentration and speciation along the water flow path between cells as well as within the cells. Arsenic concentrations in the water increased linearly with Cl(-), a conservative ion from evapoconcentration. Reduced As species as arsenite [As(III)] and organic arsenic (org-As) also increased with increases in Cl(-) and salinity. Water samples with elevated EC (i.e., towards the end of flow path) had high dissolved organic matter, low dissolved oxygen, and elevated sulfide concentrations, indicating the development of reducing conditions. We hypothesize that such changes could facilitate the reduction of arsenate [As(V)] to As(III) and org-As. Elevated As in sediment profiles indicate a solid phase sink mechanism, but not significant enough to remove and reduce As concentrations in the water columns. These findings help us better define the processes that affect As in drainage facilities and contribute to our understanding of how As behaves in other regions of the world that have similar climatic and hydrogeochemical conditions. PMID:17215022

Gao, S; Ryu, J; Tanji, K K; Herbel, M J

2007-01-09

270

Does evaporation paradox exist in China?  

NASA Astrophysics Data System (ADS)

One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called the evaporation paradox. Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The following conclusions were made: (1) From 1956 to 2005, pan evaporation paradox exists in China as a whole with decreasing in pan evaporation and the warming though it does not exist in Northeast and Southeast; (2) From 1956 to 1985, pan evaporation paradox exists narrowly as a whole with unobvious warming though it does not exist in Northeast (3) From 1986 to 2005, in the past 50 years, the precipitation and the pan evaporation exhibit contrary trend in most areas. Furthermore, pan evaporation paradox does not exist as a whole with increasing in pan evaporation though it exists in South. Furthermore, the trend of other weather factors including sunlight time, windspeed, humidity and vapor pressure deficit and their relation with pan evaporation are discussed. It can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the deceasing in vapor pressure deficit due to strong warming after 1986.

Cong, Z. T.; Yang, D. W.

2008-08-01

271

Waste Water Evaporation Process for Fertilizer Production Technology by the ODDA Method. Compendium on Low- and Non-Waste Technology.  

National Technical Information Service (NTIS)

NPK fertilizers, a nitro-phosphate type fertilizer, is produced through the Norsk-Hydro-ODDA technology. This technology has been modified to incorporate an effective wastewater evaporator system which reduces the amount of contaminated cooling water disc...

1982-01-01

272

Climate Processes of Lake Evaporation and Snowmelt Runoff: Part I. Evaporation Rates from Temperature-Stratified Saline - Lake as a Case Study. Part II. Snowmelt Runoff and Climate - Lake Basin as a Case Study  

Microsoft Academic Search

In part I, a methodology for determining the evaporation rates from temperature-stratified saline lakes has been developed. The initial motivation was to develop a technique which would be more accurate than the widely used evaporation pan method, and which would use meteorological data inputs that are normally available at weather stations, or are otherwise easy and inexpensive to gather. Four

Ben Jei Tsuang

1990-01-01

273

Water Vapor Emission From Rigid Mesoporous Materials during the Constant Drying Rate Period  

Microsoft Academic Search

It has long been thought that the evaporation rate from mesoporous materials during the constant drying rate period (CDRP) is equal to that of a free-water surface, due to the presence of a liquid film covering the surface of the material. In this article we review several early articles and demonstrate that the experimental scrutiny this hypothesis has received is

T. Diaz Gonçalves; V. Brito; L. Pel

2012-01-01

274

Is the Evaporation Rate of Methane from Titan's Lakes Greatly Overestimated?  

NASA Astrophysics Data System (ADS)

The only certain and known source of methane for the atmosphere of Titan on short timescales is the volatile organic lake reservoirs. In general, there will be a turbulent exchange of methane and sensible heat between the atmosphere and the surface of these lakes. The turbulent fluxes of methane and heat are controlled by a variety of factors that includes: the temperature of the lake and atmosphere, the molar fraction of methane in the lake, the methane vapor pressure of the air, the wind speed, the atmospheric stability, and the solar and infrared heat available to drive the system. In addition, the dynamics of both the lake and the atmosphere influence how the turbulent fluxes evolve over time. We present results from numerical simulations that explicitly calculate the turbulent fluxes of methane and energy at a lake surface under a variety of conditions. Results show that evaporative cooling of the lakes results in the production of a low level atmospheric inversion that drastically diminishes the magnitude of the fluxes by suppressing turbulent winds and lowering the bulk exchange coefficient. These results suggest that the rate at which lakes can supply methane to the atmosphere has been greatly overestimated. This work was supported by the NASA Planetary Atmospheres Program under Grant NNX10AB97G.

Rafkin, Scot C. R.

2012-10-01

275

Reduced energy consumption evaporator for use in desalting impaired waters. Technical completion report (Final)  

SciTech Connect

The basic objective of this program is to demonstrate significant savings in energy consumption by the use of the wiped film rotating disk (WFRD) evaporator in a five-effect vapor compression distillation (MEVCD) system to recover the maximum amount of water from agricultural drainage water and other impaired waters. Tests were conducted using a 10,000 ppm aqueous solution of sodium sulfate and sodium chloride to simulate the composition of agricultural drainage water in the San Joaquin Valley, California. The feed was concentrated by a factor ranging from 15 to 20 resulting in a blowdown salinity of 150,000 to 200,000 ppm. The results showed the presence of dissolved salts has significant influence on energy consumption by the compressor of a commercial 60,000 gal/day VCD unit tested at Los Banos, California.

Tleimat, B.W.; Tleimat, M.C.

1995-06-01

276

Minimum Sparge Rate to Suspend Solid Particles in the 2H-Evaporator  

SciTech Connect

SRS High Level Waste (HLW) requested Savannah River Technology Center to determine the requirements for suspending insoluble solids in the 2H-evaporator pot. The evaporator pot is a cylindrical vessel with a conical bottom, an air lance, and the suction line to a transfer pump. The air lance and pump suction are located at the bottom of the pot, which will contain insoluble sodium aluminosilicate and sodium diuranate particles.

Poirier, M.R.

2000-09-21

277

Minihalo photoevaporation during cosmic reionization: evaporation times and photon consumption rates  

NASA Astrophysics Data System (ADS)

The weak, R-type ionization fronts (I-fronts) which swept across the intergalactic medium during the reionization of the Universe often found their paths blocked by cosmological minihaloes (haloes with virial temperatures Tvir<= 104 K). When this happened, the neutral gas which filled each minihalo was photoevaporated. In a cold dark matter universe, minihaloes formed in abundance before and during reionization and, thus, their photoevaporation is an important, possibly dominant, feature of reionization, which slowed it down and cost it many ionizing photons. In a previous paper, we described this process and presented our results of the first simulations of it by numerical gas dynamics with radiation transport in detail. In view of the importance of minihalo photoevaporation, both as a feedback mechanism on the minihaloes and as an effect on cosmic reionization, we have now performed a larger set of high-resolution simulations to determine and quantify the dependence of minihalo photoevaporation times and photon consumption rates on halo mass, redshift, ionizing flux level and spectrum. We use these results to derive simple expressions for the dependence of the evaporation time and photon consumption rate on these halo and external flux parameters. These can be conveniently applied to estimate the effects of minihaloes on the global reionization process in both semi-analytical calculations and larger-scale, lower-resolution numerical simulations, which cannot adequately resolve the minihaloes and their photoevaporation. We find that the average number of ionizing photons each minihalo atom absorbs during its photoevaporation is typically in the range 2-10. For the collapsed fraction in minihaloes expected during reionization, this can add about one photon per total atom to the requirements for completing reionization, potentially doubling the minimum number of photons required to reionize the Universe.

Iliev, Ilian T.; Shapiro, Paul R.; Raga, Alejandro C.

2005-08-01

278

Concurrent Comparisons of Stomatal Behavior, Water Status, and Evaporation of Maize in Soil at High or Low Water Potential  

PubMed Central

Concurrent measurements of evaporation, leaf conductance, irradiance, leaf water potential, and osmotic potential of maize (Zea mays L. cv. Pa602A) in soil at either high or low soil water potential were compared at several hours on two consecutive days in July. Hourly evaporation, measured on two weighing lysimeters, was similar until 1000 hours Eastern Standard Time, but thereafter evaporation from the maize in the dry soil was always less than that in the wet soil; before noon it was 62% and by midafternoon, only 35% of that in the wet soil. The leaf water potential, measured with a pressure chamber, was between ?1.2 and ?2.5 bars and between ?6.8 and ?8 bars at sunrise (about 0530 hours Eastern Standard Time) in the plants in the wet and dry soil, respectively, but decreased quickly to between ?8 and ?13 bars in the plants in the wet soil and to less than ?15 bars in the plants in the dry soil by 1100 to 1230 hours Eastern Standard Time. At this time, the leaf conductance of all leaves was less than 0.1 cm sec?1 in the maize in the dry soil, whereas the conductance was 0.3 to 0.4 cm sec?1 in the leaves near the top of the canopy in the wet soil. The osmotic potential, measured with a vapor pressure osmometer, also decreased during the morning but to a smaller degree than leaf water potential, so that by 1100 to 1230 hours Eastern Standard Time the leaf turgor potential was 1 to 2 bars in all plants. Thereafter, leaf turgor potential increased, particularly in the plants in soil at a high water potential, whereas leaf water potential continued to decrease even in the maize leaves with partly closed stomata. Evidently maize can have values of leaf conductance differing 3- to 4- fold at the same leaf turgor potential, which suggests that stomata do not respond primarily to bulk leaf turgor potential. Evidence for some osmotic adjustment in the plants at low soil water potential is presented. Although the degree of stomatal closure in the maize in dry soil did not prevent further development of stress, it did decrease evaporation in proportion to the decrease in canopy conductance.

Turner, Neil C.

1975-01-01

279

A laboratory study on the uptake of HCl, HNO 3, and SO 2 gas by ice crystals and the effect of these gases on the evaporation rate of the crystals  

Microsoft Academic Search

The results of our new and earlier laboratory studies on the uptake of gases by ice crystals are summarized in terms of (1) the equilibrium phase diagram for a system gas\\/H2O, (2) the effect of these gases on the evaporation rate of ice crystals, and (3) in terms of the uptake of the gases by water drops. It is shown

K Diehl; S. K Mitra; H. R Pruppacher

1998-01-01

280

Evaporating droplets  

NASA Astrophysics Data System (ADS)

In our everyday life we are constantly confronted with evaporating drops and the consequences of it. The seemingly simple problem of an evaporating droplet has attracted a great deal of attention over the past years. The problem is complicated due to the fact that the form of the droplet during the evaporation is a priori unknown, and due to the large number of effects that have to be taken into account (temperature, convection, Marangoni effects). We consider the very simple situation of the evaporation of a perfectly wetting liquid on a molecularly smooth surface. The radius R(t) of the droplet is followed in time until it reaches zero. If the evaporation is purely diffusive, a radius that decreases as the square root of time is expected; this is indeed found for organic liquids, but water has a different exponent. We show that the difference is likely to be due to the fact that water vapor is lighter than air, and the vapor of other liquids more dense. If we carefully confine the water so that the diffusive boundary layer may develop, we retrieve the square root of time behavior. On the other hand, if we force convection for an organic liquid, we retrieve the anomalous exponent for water.

Shahidzadeh-Bonn, Noushine; Rafai, Salima; Azouni, Aza; Bonn, Daniel

2006-03-01

281

Some critical transitions in pool flash evaporation  

Microsoft Academic Search

To improve the fundamental understanding of the physics of the flash evaporation process, pool flash evaporation experiments were conducted in a 152 mm diameter chamber with initial water temperatures of 40–80°C, and superheats of 2–7°C. Several critical transition points were identified or discovered: (1) a critical time at which the rate of ebullition and evaporation diminishes abruptly, (2) an initial

Noam Lior

1997-01-01

282

Water retention curves of loamy-sandy soils: Transient evaporation method versus steady-state tension and pressure techniques  

Microsoft Academic Search

Water retention curves of loamy-sandy soils at the agricultural test site Wagna (Austria) were measured using both the simplified evaporation method according to Schindler (Arch. Acker- u. Pflanzenbau u. Bodenkd. Berlin 24, 1-7, 1980) and steady-state tension and pressure techniques. The soil was sampled with 250-ccm and 100-ccm steel pipes for the evaporation method and the steady-state technique, respectively. In

G. Winkler; E. Eberhard; J. Fank; S. Birk

2009-01-01

283

Water Requirements and Application Rates for Lawns.  

National Technical Information Service (NTIS)

Lawn water application rates were measured for 55 homes in Laramie and Wheatland, Wyoming, during 1975 and 1976. In addition, evapotranspiration rates were measured at both cities during 1976. Lawn water application rates in 1976 were 122 percent of the a...

L. O. Pochop J. Borrelli J. R. Barnes P. K. O'Neill

1978-01-01

284

Does evaporation paradox exist in China?  

Microsoft Academic Search

One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called \\

Z. T. Cong; D. W. Yang; G. H. Ni

2009-01-01

285

Disposal of Brine by Solar Evaporation.  

National Technical Information Service (NTIS)

An investigation was made to determine the rate of evaporation of brine in solar ponds by methods of energy budget, water budget and mass transfer. The investigation included the effect of salinity and dyes on solar evaporation of brine at Roswell, New Me...

C. G. Keyes N. N. Gunaji

1968-01-01

286

Open fibre reinforced plastic (FRP) flat plate collector (FPC) and spray network systems for augmenting the evaporation rate of tannery effluent (soak liquor)  

Microsoft Academic Search

Presently, tanneries in Tamilnadu, India are required to segregate the effluent of soaking and pickling sections from other wastewater streams and send it to shallow solar pans for evaporation to avoid land pollution. A large area of solar pans is required for evaporating the water in the effluent at salt concentration in the range of 4–5%. An experimental study has

K. Srithar; A. Mani

2007-01-01

287

Preliminary evaluation of the performance, water use, and current application trends of evaporative coolers in California climates  

SciTech Connect

This paper describes the latest results of an ongoing analysis investigating the potential for evaporative cooling as an energy-efficient alternative to standard air-conditioning in California residences. In particular, the study uses detailed numerical models of evaporative coolers linked with the DOE-2 building energy simulation program to study the issues of indoor comfort, energy and peak demand savings with and without supplemental air-conditioning and consumptive water use. In addition, limited surveys are used to assess the current market availability of evaporative cooling in California, typical contractor practices and costs, and general acceptance of the technology among engineers, contractors, and manufacturers. The results show that evaporative coolers can provide significant energy and peak demand savings in California residences, but the impact of the increased indoor humidity on human comfort remains an unanswered question that requires further research and clarification. Evaluated against ASHRAE comfort standards developed primarily for air-conditioning both direct and two-stage evaporative coolers would not maintain comfort at peak cooling conditions due to excessive humidity. However, using bioclimatic charts that place human comfort at the 80% relative humidity line, the study suggests that direct evaporative coolers will work in mild coastal climates, while two-stage models should provide adequate comfort in Title 24 houses throughout California, except in the Imperial Valley. The study also shows that evaporative coolers will increase household water consumption by less than 6% on an annual basis, and as much as 23% during peak cooling months, and that the increases in water cost are minimal compared to the electricity savings. Lastly, a survey of engineers and contractors revealed generally positive experiences with evaporative coolers, with operational cost savings, improved comfort, unproved air quality as the primary benefits in their use.

Huang, Y.J.; Hanford, J.W.; Wu, H.F.

1992-09-01

288

The Rate of Evaporation of Liquids in a Current of Air  

Microsoft Academic Search

The experiments were made in a large ventilating tunnel at Edgewood Arsenal near the end of a 280 ft straight section, 6 ft square. The liquid being studied was pumped continuously into a copper pan mounted flush with the floor, over the edge of which it overflowed into a lower pan. The amount of evaporation in several hours was determined

T. B. Hine

1924-01-01

289

On the evaporation rate of ultra-thin liquid film at the nanostructured surface: A molecular dynamics study  

Microsoft Academic Search

Molecular dynamic (MD) simulations have been carried out to study the effect of the nanostructures on the evaporation rate of the ultra-thin liquid film at the solid surface. Simple Lennard-Jones (LJ) fluids are simulated as the ultra-thin liquid film in the non-equilibrium simulation system. The liquid film is confined in a nanochannel composed of two solid surfaces designed with nanostructures

Gyoko Nagayama; Masako Kawagoe; Atsushi Tokunaga; Takaharu Tsuruta

2010-01-01

290

Measurement of total and condensed water mixing ratios in warm-based cumulus clouds by a jet engine evaporation technique  

Microsoft Academic Search

A technique has been developed for measuring total water mixing ratio and condensed water mixing ratio in warm-based convective clouds. The jet engine compressor on a Learjet 24 is employed as an evaporator to convert all cloud condensate to vapour and the vapour density in the compressed (bleed) air is measured with a Lyman-alpha humidiometer.

G. Morgan; B. J. Morrison; G. K. Mather

1989-01-01

291

Horizontal convection in water heated by infrared radiation and cooled by evaporation: scaling analysis and experimental results  

Microsoft Academic Search

An experimental study of horizontal convection with a free surface has been conducted. Fresh water was heated from above by an infrared lamp placed at one end of a tank, and cooled by evaporation as the water moved away from the heat source. The heat radiated from the lamp was absorbed in a thin (less than 1 mm) layer next

A. K. Wåhlin; A. M. Johansson; E. Aas; G. Broström; J. E. H. Weber; J. Grue

2010-01-01

292

Evaporative cooling in insects  

Microsoft Academic Search

Insects commonly use behavior to avoid the heat stress and consequent water loss of hot environments. It has been assumed by many to be impossible or impractical for insects to employ evaporative cooling. Despite this assumption, there have been many instances, historically and recently where insects are reported to survive otherwise lethal temperatures by evaporating water. The site of evaporation

Henry D. Prange

1996-01-01

293

State-of-the-art evaporation technology: Topical report  

SciTech Connect

This report discusses evaporation theory, measurement and estimation as well as the effects of water quality on evaporation. Emissions from waste effluents is also mentioned. The theory and equations to represent evaporation using energy balances, mass transport and the combination of these two methods of analysis are presented in detail. Evaporation meters and other techniques for measuring evaporation are reviewed. A discussion of ways to estimate areal evaporation is presented along with criteria which affects evaporation pond design. The effects of chemical monolayers and salinity on the rate of evaporation is cited and discussed to indicated problems associated with most industrial waste effluents. The problem of monitoring emissions resulting from evaporation ponds associated with industrial waste emissions is also presented.

Hasfurther, V.R.; Haass, M.J.

1986-09-01

294

Nonempirical statistical theory for atomic evaporation from nonrigid clusters: applications to the absolute rate constant and kinetic energy release.  

PubMed

A high energy atomic cluster undergoing frequent structural isomerization behaves like a liquid droplet, from which atoms or molecules can be emitted. Even after evaporation, the daughter cluster may still keep changing its structure. We study the dynamics of such an evaporation process of atomic evaporation. To do so, we develop a statistical rate theory for dissociation of highly nonrigid molecules and propose a simple method to calculate the absolute value of classical phase-space volume for a potential function that has many locally stable basins. The statistical prediction of the final distribution of the released kinetic energy is also developed. A direct application of the Rice-Ramsperger-Kassed-Marcus (RRKM) theory to this kind of multichannel chemical reaction is prohibitively difficult, unless further modeling and/or assumptions are made. We carry out a completely nonempirical statistical calculation for these dynamical quantities, in that nothing empirical is introduced like remodeling (or reparametrization) of artificial potential energy functions or recalibration of the phase-space volume referring to other "empirical" values such as those estimated with the molecular dynamics method. The so-called dividing surface is determined variationally, at which the flux is calculated in a consistent manner with the estimate of the phase-space volume in the initial state. Also, for the correct treatment of a highly nonrigid cluster, the phase-space volume and flux are estimated without the separation of vibrational and rotational motions. Both the microcanonical reaction rate and the final kinetic energy distribution thus obtained have quite accurately reproduced the corresponding quantities given by molecular dynamics calculations. This establishes the validity of the statistical arguments, which in turn brings about the deeper physical insight about the evaporation dynamics. PMID:17279737

Fujii, Mikiya; Takatsuka, Kazuo

2007-02-06

295

Evaporative tunnel cooling of dairy cows in the southeast. I: effect on body temperature and respiration rate.  

PubMed

The techniques used to mitigate the effects of heat stress on lactating dairy cows are often overwhelmed in the southeastern United States, where elevated heat and humidity often persist for extended periods. A model free-stall barn located at the North Mississippi Branch Experiment Station in Holly Springs was used to evaluate the potential of tunnel ventilation with evaporative cooling to alleviate heat stress in lactating dairy cows. Two studies were conducted using 2 groups of 10 lactating Holsteins housed in the tunnel barn (inside) and 2 groups of matched herdmates housed in an adjacent covered free-stall barn (outside), which was cooled by fans and sprinklers during 2001 or by shade and fans alone in 2003. Peak daytime temperatures inside were 5.2 +/- 0.18 degrees C below that outside in 2001 and 3.1 +/- 0.20 degrees C lower in 2003. Although evaporative cooling increased humidity by 22%, cows housed in the tunnel barn received 84% less exposure to moderate heat stress (temperature-humidity index > 80) in both years. Cooling cows with evaporative tunnel ventilation reduced respiration rates by 15.5 +/- 0.56 breaths/min and rectal temperatures by 0.6 +/- 0.02 degrees C compared with shade and fans alone in 2003. Cooling cows with evaporative tunnel ventilation reduced respiration rates by 13.1 +/- 0.78 breaths/min and rectal temperatures by 0.4 +/- 0.03 degrees C compared with fans and sprinklers in 2001. Thus, tunnel ventilation cooling dramatically reduced the exposure to heat stress and improved the comfort of lactating dairy cows when compared with traditional cooling technologies under the conditions present in the southeastern United States. PMID:16960066

Smith, T R; Chapa, A; Willard, S; Herndon, C; Williams, R J; Crouch, J; Riley, T; Pogue, D

2006-10-01

296

Determination of evaporation from a catchment water balance at a monthly time scale  

NASA Astrophysics Data System (ADS)

A method is presented to determine total evaporation from the earth's surface at a spatial scale that is adequate for linkage with climate models. The method is based on the water balance of catchments, combined with a calibrated autoregressive rainfall-runoff model. The time scale used is in the order of decades (10 days) to months. The rainfall-runoff model makes a distinction between immediate processes (interception and short term storage) and the remaining longer-term processes. Besides the calibrated rainfall-runoff model and the time series of observed rainfall and runoff, the method requires a relation between transpiration and soil moisture storage. The method is applied to data of the Bani catchment in Mali, a sub-catchment of the Niger river basin.

Savenije, H. H. G.

297

Evolution of trimethylarsine by a Penicillium sp. isolated from agricultural evaporation pond water.  

PubMed

Arsenicals are used in agriculture as pesticides and defoliants. In the Central Valley of California, arsenic is present in soil at naturally high concentrations, being derived from marine sedimentary parent material of the Coastal Range. Due to intense agricultural irrigation, soluble arsenic is leached from the soil and accumulates in evaporation ponds where it may pose an environmental threat to the waterfowl and wildlife. A Penicillium sp. isolated from evaporation pond water was found to be capable of methylating and subsequently volatilizing organic arsenic. The major focus of this study was to characterize the environmental conditions, including culture media, arsenic substrates, pH, temperature, and the presence of phosphates, carbohydrates and amino acids on the methylation of arsenic. Trimethylarsine was monitored by gas chromatography (GC)-flame ionization detection and identified by GC-mass spectrometry. The conditions or additions for optimum trimethylarsine production were: a minimal medium in which 100 mgl-1 methylarsonic acid served as the arsenic source, pH 5-6, temperature of incubation 20 degrees C, and phosphate concentration of 0.1-50 mM (KH2PO4). The addition of carbohydrates and sugar acids to the minimal medium suppressed trimethylarsine production. The amino acids phenylalanine, isoleucine, and glutamine promoted trimethylarsine production with an enhancement ranging from 10.2- to 11.6-fold over the control without amino acid supplementation. The information obtained from this study may be useful in developing a bioremediation approach in trapping the arsenic gas evolved from soil or water as a mitigation alternative in the cleanup of arsenic contamination. PMID:1925518

Huysmans, K D; Frankenberger, W T

1991-06-01

298

On the evaporation of ammonium sulfate solution  

PubMed Central

Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 ± 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor–liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

2009-01-01

299

Tried and True: Evaporating is cool  

NSDL National Science Digital Library

Many students hold misconceptions about evaporation. In this short exercise, students will apply the kinetic molecular theory to explain how cold water can evaporate and to observe the cooling effect of evaporation, and develop their own evaporation experiments.

Hand, Richard

2006-03-01

300

Reservoir Evaporation Prediction Using Data Driven Techniques  

Microsoft Academic Search

Evaporation in reservoirs plays a prominent role in water resources planning, operation, and management because a considerable amount of water is lost through evaporation, especially in large reservoirs. Estimating evaporation from surface water usually requires ample data that are not easily measurable. At present, in India, reservoir evaporation is estimated from the pan evaporation and average water spread area. Because

R. Arunkumar; V. Jothiprakash

2013-01-01

301

Reaction rate constant for uranium in water and water vapor  

SciTech Connect

The literature on uranium oxidation in water and oxygen free water vapor was reviewed. Arrhenius rate equations were developed from the review data. These data and equations will be used as a baseline from which to compare reaction rates measured for K Basin fuel.

TRIMBLE, D.J.

1998-11-09

302

Evaporation measurements on enhanced water-permeable paving in urban areas  

Microsoft Academic Search

Pavements consisting of water-permeable paving stone have a certain retention and storage capability for rainwater in the event of intense rain. Applied on a large surface, this results in a mitigation of flood events. Compared to an impermeable surface area, the surface flow rate decreases while groundwater regeneration increases. To date, the actual change in the third water balance parameter,

Patricia Göbel; Phillip Starke; Wilhelm G. Coldewey

303

Boron isotope variations during fractional evaporation of sea water: New constraints on the marine vs. nonmarine debate  

NASA Astrophysics Data System (ADS)

Examination of boron isotopes, elemental B, Br, and Li in brines, and coprecipitated salts during fractional evaporation of sea water shows that Br, Li, and B in the evaporated sea water have lower concentrations than expected, as determined from mass-balance calculations. The deficiency is found beyond a degree of evaporation of ˜30 and is associated with a gradual increase in the ?11B values of the evaporated sea water, from 39‰ to 54.7‰ (relative to standard NBS 951). The high ?11B values of the brines and the relatively lower ?11B values of the coexisting precipitates (MgSO4 and K-MgSO4 salts; ?11B = 11.4‰ to 36.0‰) suggest selective uptake of 10B by the salts. Applying Rayleigh distillation equations, the empirical fractionation factors for the depletion of the salts in 11B are estimated as 30‰ (? = 0.969) for the early stages of precipitation (gypsum and halite range) and 20‰ (? = 0.981) for the late stages (K-MgSO4 minerals). Coprecipitation of B(OH)4- species with the salts, and/or precipitation of Mg-borate minerals with a coordination number of 4 are the proposed mechanisms for boron isotope fractionation during fractional evaporation of sea water. The boron isotope composition of sea water (?11B = 39‰) is significantly higher than that of continental water (?11B = -3‰ ±5‰). Our study shows that salt deposits may be depleted in 11B by 20‰ to 30‰ relative to their parent brines. These variations suggest that boron isotopes can be used to determine the origin (marine vs. nonmarine) of brines and ancient evaporitic environments.

Vengosh, Avner; Starinsky, Abraham; Kolodny, Yehoshua; Chivas, Allan R.; Raab, Menahem

1992-09-01

304

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996.  

National Technical Information Service (NTIS)

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced w...

J. A. Harju J. E. Boysen J. L. Mefford J. R. Kirsch K. L. Walker

1996-01-01

305

RELATIONSHIP BETWEEN A SOLAR DRYING MODEL OF RED PEPPER AND THE KINETICS OF PURE WATER EVAPORATION (II)  

Microsoft Academic Search

In part one, a simple drying model of red pepper related to water evaporation was developed. In this second part the drying model is applied by means of related experiments.Both laboratory and open air drying experiments were carried out to validate the model and simulation results are presented.

Victor Passamai; Luis Saravia

1997-01-01

306

Evaporative instabilities  

NASA Astrophysics Data System (ADS)

Evaporation plays a major role in many industrial and physical processes ranging from heat pipes and the drying of magnetic films to the drying of the tear film in the eye. We investigated, theoretically, the gravity and surface tension gradient-driven instabilities occurring during the evaporation of a liquid into its own vapor taking into account the fluid dynamics of both phases. The liquid and its vapor are assumed to be confined between two horizontal plates, and different heating arrangements are applied. The effects of fluid layer depths, the evaporation rate and the temperature gradient applied across the fluids on the stability of the interface are studied. The modes of the flow pattern are determined for each scenario. The physics of the instability are explained and a comparison is made with the results of similar, yet different problems.

Ozen, O.

307

Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry ( Morus nigra ) juice concentrate  

Microsoft Academic Search

Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating,\\u000a at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes\\u000a of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at\\u000a 100, 38.5, and 7.3 kPa respectively by using

Mahboubeh Fazaeli; Ghazale Hojjatpanah; Zahra Emam-Djomeh

308

Performance of constructed evaporation ponds for disposal of smelter waste water: a case study at Portland Aluminum, Victoria, Australia.  

PubMed

The construction of evaporative ponds and wetlands for the disposal of waste water high in ionic concentrations is a waste disposal strategy currently considered by many industries. However, the design, construction and management of these ponds and wetlands are not straightforward as complex chemical interactions result in both spatial and temporal changes in water quality. The effects of evaporation and drainage on the water quality in two constructed ponds, an adjacent man-made wetland and local groundwater at Portland Aluminium were investigated. The minimum volume of water entering the ponds during the study period was 0.96 +/- 0.16 ML per month. The predicted theoretical evaporative capacity of the two ponds was calculated to be 0.30 +/- 0.07 ML per month. More water enters the ponds than it is theoretically possible to evaporate under the ambient weather conditions at Portland, yet the ponds do not overflow, suggesting percolation through the pond lining. No spatial differences in solute concentrations (fluoride, sulphate, bicarbonate, carbonate, sodium, potassium, calcium, and magnesium ions) were found within the waters of either pond, although temporal differences were apparent. The results support the conclusion that the ponds are not impermeable, and that much of the waste water entering the ponds is being lost through seepage. The impacts on local groundwater chemistry of this seepage are addressed. Significant correlations exist between solute presence within and between the ponds. wetland and groundwater. Fluoride and sulphate concentrations were significantly higher in pond waters throughout the duration of the experiment. Pond sediments revealed a high degree of spatial and temporal heterogeneity in the concentration of all monitored ions resulting from the chemical heterogeneity of the material making up the pond linings. Adsorption isotherms for fluoride indicate that the adsorption capacity of the pond linings remains high for this ion. Implications for the management of waste water by this strategy are discussed. PMID:11358290

Salzman, S A; Allinson, G; Stagnitti, F; Coates, M; Hill, R J

2001-06-01

309

Evaporative water loss: thermoregulatory requirements and measurements in the deer mouse and white rabbit  

Microsoft Academic Search

Using a physical model of the capacity for non-evaporative heat loss and measurements of metabolic heat production, I evaluated the evaporative requirements for thermoregulation in the deer mouse,Peromyscus maniculatus, and the white rabbit,Oryctolagus cuniculus. The physical limit to non-evaporative heat loss was calculated from the heat transfer properties of the two animals and expressed as a maximum thermal conductance (Cmax).

Kevin E. Conley

1985-01-01

310

Experimental and theoretical investigations on interfacial temperature jumps during evaporation  

Microsoft Academic Search

Experimental results are summarized on investigations of positive temperature jumps at water–vapor interfaces during steady-state evaporation under low-pressure. Steady-state evaporation of water experiments were carried out to measure the interfacial properties and to obtain the evaporation rate. The interfacial vapor temperature close to the interface was always found to be higher than the interfacial liquid temperature. To study the influence

V. K. Badam; V. Kumar; F. Durst; K. Danov

2007-01-01

311

Concentrating solar collector system for the evaporation of low-level radioactive waste water  

SciTech Connect

The Los Alamos National Laboratory has recently been awarded a grant under the Solar Federal Buildings Program to design, construct, and operate a high-temperature solar energy system for the processing of low-level radioactive waste water. Conceptual design studies have been completed, and detailed design work is under way for a solar system to produce process heat to evaporate 38,000 gal (143,830 L) of waste water per month. The system will use approximately 11,000 ft/sup 2/ (1022 m/sup 2/) of concentrating parabolic trough collectors operating at about 500/sup 0/F (262/sup 0/C). Construction of the system is anticipated to begin in 1981. Performance optimization of collector array size and configuration, storage medium and capacity, system operation, and control schemes are done using the active solar system simulator in the DOE-2 building energy analysis computer program. Results of this optimization are reported. This project represents a unique application of solar energy to an increasingly significant problem area in the energy field.

Diamond, S.C.; Cappiello, C.C.

1981-01-01

312

[Method for study of phase transitions in evaporating drop and its application for evaluation of physical-chemical properties of water and water solutions].  

PubMed

Spatial-temporal crystallization features of inorganic chlorides in evaporating drops of water solutions, considering solid surface wettability, were studied using a microscopic technique and the acoustical impedansometry. Physical-chemical mechanisms responsible for the difference in "dynamical portraits" of distilled water and salt solutions, as well as relaxation effects in water were discussed. The study demonstrated the potential use of a drying drop method in registration of changes in water properties under the action of physical and chemical factors. PMID:23272573

Iakhno, T A; Sanin, A G; Sanina, O A; Iakhno, V G

313

Does evaporation paradox exist in China?  

NASA Astrophysics Data System (ADS)

One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called "evaporation paradox". Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The conclusions include: (1) From 1956 to 2005, pan evaporation paradox existed in China as a whole while pan evaporation kept decreasing and air temperature became warmer and warmer, but it does not apply to Northeast and Southeast China; (2) From 1956 to 1985, pan evaporation paradox existed narrowly as a whole with unobvious climate warming trend, but it does not apply to Northeast China; (3) From 1986 to 2005, in the past 20 years, pan evaporation paradox did not exist for the whole period while pan evaporation kept increasing, although it existed in South China. Furthermore, the trend of other weather factors including sunshine duration, windspeed, humidity and vapor pressure deficit, and their relations with pan evaporation are discussed. As a result, it can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the decreasing in vapor pressure deficit due to strong warming after 1986. With the Budyko curve, it can be concluded that the actual evaporation decreased in the former 30 years and increased in the latter 20 year for the whole China.

Cong, Z. T.; Yang, D. W.; Ni, G. H.

2009-03-01

314

Potential evaporation functions compared on US watersheds: Possible implications for global-scale water balance and terrestrial ecosystem modeling  

Microsoft Academic Search

Estimates of potential evaporation Ep are commonly employed in terrestrial water balance and net primary productivity models. This study compared a set of 11 Ep methods in a global-scale water balance model (WBM) applied to 3265 0.5° (lat. × long.) grid cells representing the conterminous US. The Ep methods ranged from simple temperature-driven equations to physically-based combination approaches and include

C. J. Vörösmarty; C. A. Federer; A. L. Schloss

1998-01-01

315

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Final report, August 1992August 1996  

Microsoft Academic Search

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil

J. E. Boysen; K. L. Walker; J. L. Mefford; J. R. Kirsch; J. A. Harju

1996-01-01

316

Effects of Changes in Meteorological Conditions on Lake Evaporation, Water Temperature, and Heat Budget in a Deep Lake  

NASA Astrophysics Data System (ADS)

To reveal effects of changes in meteorological conditions on lake evaporation, water temperature, and heat budget in a deep lake, sensitivity analyses have been performed for Lake Ikeda, Kagoshima prefecture. In the study, the sensitivities of three aspects to the 10%-increased solar radiation, air temperature, relative humidity, and wind speed were estimated based on numerical calculations for 1981-2005 with the verified one-dimensional mathematical model that computes thermal transfer in the lake. The results demonstrated that the meteorological component which gives the largest evaporation-promoting effect was solar radiation and the component which brings the largest lake-heating was air temperature. When solar radiation was increased, the vapor pressure difference between lake-surface and atmosphere was increased and the atmospheric stability was decreased, which present the desirable condition for evaporation. Air temperature being higher, the lake-surface was intensively heated by increased atmospheric radiation. As for the humidity case, lake evaporation was decreased in any season due to decrease in vapor pressure difference. Although rise in water temperature was caused by decrease in latent heat, it was inhibited with cooling by sensible heat. Wind being up, water temperature was fallen at the lake-surface and risen around the 20 m depth by vertical thermal mixing effect. The mixing effect prevented from releasing heat to atmosphere, resulting in the secondary large lake-heating but smaller than air temperature case.

Ito, Yuji; Momii, Kazuro

317

Estimation of evaporation from open water - A review of selected studies, summary of U.S. Army Corps of Engineers data collection and methods, and evaluation of two methods for estimation of evaporation from five reservoirs in Texas  

USGS Publications Warehouse

Organizations responsible for the management of water resources, such as the U.S. Army Corps of Engineers (USACE), are tasked with estimation of evaporation for water-budgeting and planning purposes. The USACE has historically used Class A pan evaporation data (pan data) to estimate evaporation from reservoirs but many USACE Districts have been experimenting with other techniques for an alternative to collecting pan data. The energy-budget method generally is considered the preferred method for accurate estimation of open-water evaporation from lakes and reservoirs. Complex equations to estimate evaporation, such as the Penman, DeBruin-Keijman, and Priestley-Taylor, perform well when compared with energy-budget method estimates when all of the important energy terms are included in the equations and ideal data are collected. However, sometimes nonideal data are collected and energy terms, such as the change in the amount of stored energy and advected energy, are not included in the equations. When this is done, the corresponding errors in evaporation estimates are not quantifiable. Much simpler methods, such as the Hamon method and a method developed by the U.S. Weather Bureau (USWB) (renamed the National Weather Service in 1970), have been shown to provide reasonable estimates of evaporation when compared to energy-budget method estimates. Data requirements for the Hamon and USWB methods are minimal and sometimes perform well with remotely collected data. The Hamon method requires average daily air temperature, and the USWB method requires daily averages of air temperature, relative humidity, wind speed, and solar radiation. Estimates of annual lake evaporation from pan data are frequently within 20 percent of energy-budget method estimates. Results of evaporation estimates from the Hamon method and the USWB method were compared against historical pan data at five selected reservoirs in Texas (Benbrook Lake, Canyon Lake, Granger Lake, Hords Creek Lake, and Sam Rayburn Lake) to evaluate their performance and to develop coefficients to minimize bias for the purpose of estimating reservoir evaporation with accuracies similar to estimates of evaporation obtained from pan data. The modified Hamon method estimates of reservoir evaporation were similar to estimates of reservoir evaporation from pan data for daily, monthly, and annual time periods. The modified Hamon method estimates of annual reservoir evaporation were always within 20 percent of annual reservoir evaporation from pan data. Unmodified and modified USWB method estimates of annual reservoir evaporation were within 20 percent of annual reservoir evaporation from pan data for about 91 percent of the years compared. Average daily differences between modified USWB method estimates and estimates from pan data as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 98 percent of the months. Without any modification to the USWB method, average daily differences as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 73 percent of the months. Use of the unmodified USWB method is appealing because it means estimates of average daily reservoir evaporation can be made from air temperature, relative humidity, wind speed, and solar radiation data collected from remote weather stations without the need to develop site-specific coefficients from historical pan data. Site-specific coefficients would need to be developed for the modified version of the Hamon method.

Harwell, Glenn R.

2012-01-01

318

Importance of rain evaporation and continental convection in the tropical water cycle  

Microsoft Academic Search

Atmospheric moisture cycling is an important aspect of the Earth's climate system, yet the processes determining atmospheric humidity are poorly understood. For example, direct evaporation of rain contributes significantly to the heat and moisture budgets of clouds, but few observations of these processes are available. Similarly, the relative contributions to atmospheric moisture over land from local evaporation and humidity from

John Worden; David Noone; Kevin Bowman; Reinhard Beer; Annmarie Eldering; Brendan Fisher; Michael Gunson; Aaron Goldman; Robert Herman; Susan S. Kulawik; Michael Lampel; Gregory Osterman; Curtis Rinsland; Clive Rodgers; Stanley Sander; Mark Shephard; Christopher R. Webster; Helen Worden

2007-01-01

319

TDR water content inverse profiling in layered soils during infiltration and evaporation  

NASA Astrophysics Data System (ADS)

During the last three decades, time domain reflectometry (TDR) has become one of the most commonly used tools for soil water content measurements either in laboratory or in the field. Indeed, TDR provides easy and cheap water content estimations with relatively small disturbance to the investigated soil. TDR measurements of soil water content are based on the strong correlation between relative dielectric permittivity of wet soil and its volumetric water content. Several expressions of the relationship between relative dielectric permittivity and volumetric water content have been proposed, empirically stated (Topp et al., 1980) as well as based on semi-analytical approach to dielectric mixing models (Roth et al., 1990; Whalley, 1993). So far, TDR field applications suffered the limitation due to the capability of the technique of estimating only the mean water content in the volume investigated by the probe. Whereas the knowledge of non homogeneous vertical water content profiles was needed, it was necessary to install either several vertical probes of different length or several horizontal probes placed in the soil at different depths, in both cases strongly increasing soil disturbance as well as the complexity of the measurements. Several studies have been recently dedicated to the development of inversion methods aimed to extract more information from TDR waveforms, in order to estimate non homogeneous moisture profiles along the axis of the metallic probe used for TDR measurements. A common feature of all these methods is that electromagnetic transient through the wet soil along the probe is mathematically modelled, assuming that the unknown soil water content distribution corresponds to the best agreement between simulated and measured waveforms. In some cases the soil is modelled as a series of small layers with different dielectric properties, and the waveform is obtained as the result of the superposition of multiple reflections arising from impedance discontinuities between the layers (Nguyen et al., 1997; Todoroff et al., 1998; Heimovaara, 2001; Moret et al., 2006). Other methods consider the dielectric properties of the soil as smoothly variable along probe axis (Greco, 1999; Oswald et al., 2003; Greco, 2006). Aim of the study is testing the applicability to layered soils of the inverse method for the estimation of water content profiles along vertical TDR waveguides, originally applied in laboratory to homogeneous soil samples with monotonic moisture distributions (Greco, 2006), and recently extended to field measurements with more general water content profiles (Greco and Guida, 2008). Influence of soil electrical conductivity, uniqueness of solution, choices of parametrization, parameters identifiabilty, sensitivity of the method to chosen parameters variations are discussed. Finally, the results of the application of the inverse method to a series of infiltration and evaporation experiments carried out in a flume filled with three soil layers of different physical characteristics are presented. ACKNOWLEDGEMENTS The research was co-financed by the Italian Ministry of University, by means of the PRIN 2006 PRIN program, within the research project entitled ‘Definition of critical rainfall thresholds for destructive landslides for civil protection purposes'. REFERENCES Greco, R., 1999. Measurement of water content profiles by single TDR experiments. In: Feyen, J., Wiyo, K. (Eds.), Modelling of Transport Processes in Soils. Wageningen Pers, Wageningen, the Netherlands, pp. 276-283. Greco, R., 2006. Soil water content inverse profiling from single TDR waveforms. J. Hydrol. 317, 325-339. Greco R., Guida A., 2008. Field measurements of topsoil moisture profiles by vertical TDR probes. J. Hydrol. 348, 442- 451. Heimovaara, T.J., 2001. Frequency domain modelling of TDR waveforms in order to obtain frequency dependent dielectric properties of soil samples: a theoretical approach. In: TDR 2001 - Second International Symposium on Time Domain Reflectometry for Innovative Geotechnical Applications. Northwestern Univer

Greco, R.; Guida, A.

2009-04-01

320

Field evaporation of doubly charged ions from a polar liquid  

NASA Astrophysics Data System (ADS)

The effect of charge on field evaporation of ions from polar liquids is considered. Using the electromembrane ion source, we performed mass-spectral analysis of field evaporation of ions from the solution of sodium sulfate in a water-glycerol mixture. The composition of doubly charged cluster ions in the field evaporation from glycerol is determined. The rates of the field evaporation of doubly charged ions and singly charged ions are compared. It is shown that the ion charge as well as its localization considerably influences the efficiency of field evaporation of ions from polar liquids.

Balakin, A. A.; Novikova, L. I.

2012-11-01

321

Evaporative dense water formation and cross-shelf exchange over the northwest Australian inner shelf  

NASA Astrophysics Data System (ADS)

High-resolution surveys of oceanographic and atmospheric conditions made during the winter over the inner shelf off northwest Australia are used to examine the coastal ocean response to large outgoing heat and freshwater fluxes. Relatively cool, low-humidity air blows off the Australian continent out over the tropical continental shelf, resulting in a large mean latent heat flux (-177 W m-2) that overwhelms insolation and, along with the outgoing long-wave radiation, results in substantial net cooling (-105 W m-2) and evaporative freshwater flux (0.6 cm d-1). The inner shelf is characterized by increasingly cool, salty, and dense waters onshore, with a strong front near the 25 m isobath. The front is evident in satellite sea surface temperature (SST) imagery along the majority of the northwest Australian shelf, exhibiting a complex filamentary and eddy structure. Cross-shelf buoyancy fluxes estimated from the mean, two-dimensional heat and salt budgets are comparable to parameterizations of cross-shelf eddy driven fluxes; however, the same fluxes can be achieved by cross-shelf transports in the bottom boundary layer of about 0.5 m2 s-1 (and an overlying return flow).

Shearman, R. Kipp; Brink, Kenneth H.

2010-06-01

322

Evaporation determined by the energy-budget method for Mirror Lake, New Hampshire  

USGS Publications Warehouse

Evaporation was determined by the energy-budget method for Mirror Lake during the open water periods of 1982-1987. For all years, evaporation rates were low in spring and fall and highest during the summer. However, the times of highest evaporation rates varied during the 6 yr. Evaporation reached maximum rates in July for three of the years, in June for two of the years, and in August for one of the years. The highest evaporation rate during the 6-yr study was 0.46 cm d-1 during 27 May-4 June 1986 and 15-21 July 1987. Solar radiation and atmospheric radiation input to the lake and long-wave radiation emitted from the lake were by far the largest energy fluxes to and from the lake and had the greatest effect on evaporation rates. Energy advected to and from the lake by precipitation, surface water, and ground water had little effect on evaporation rates. In the energy-budget method, average evaporation rates are determined for energy-budget periods, which are bounded by the dates of thermal surveys of the lake. Our study compared evaporation rates calculated for short periods, usually ???1 week, with evaporation rates calculated for longer periods, usually ???2 weeks. The results indicated that the shorter periods showed more variability in evaporation rates, but seasonal patterns, with few exceptions, were similar.

Winter, T. C.; Buso, D. C.; Rosenberry, D. O.; Likens, G. E.; Sturrock, Jr. , A. M.; Mau, D. P.

2003-01-01

323

Study of the vapour pressure of saturated salt solutions and their influence on evaporation rate at room temperature  

Microsoft Academic Search

Brine disposal is an important problem in desalination facilities, especially in inland plants. Nowadays, the management alternatives to treat these brines are focused on reducing brine volume to solid state. There are different treatments to reduce brine volume such as evaporation ponds, brine evaporators, evaporation with extended surfaces and zero liquid discharge technologies. With reference to the treatments based on

M. C. León-Hidalgo; J. M. Gozálvez-Zafrilla; J. Lora-García; J. M. Arnal-Arnal

2009-01-01

324

Influence of the electron beam evaporation rate of Pt and the semiconductor carrier density on the characteristics of Pt\\/n-GaAs Schottky contacts  

Microsoft Academic Search

Schottky barrier diodes (SBDs) were fabricated on epitaxially grown n-GaAs materials, with different free carrier densities, by electron beam (e-beam) evaporation of Pt at various rates. The quality of the SBDs was evaluated by standard current-voltage (I-V) measurements, while the defects introduced during e-beam evaporation were characterized by deep level transient spectroscopy (DLTS). The results showed that if the GaAs

G. Myburg; F. D. Auret

1992-01-01

325

Correction to “Numerical evaluation of subsurface soil water evaporation derived from sensible heat balance”  

Microsoft Academic Search

Heat balance method for subsurface evaporation determination was evaluatedImproved accuracy from tighter near-surface temperature measurement spacingHeat pulse probe is more accurate using locally determined thermal conductivity

Masaru Sakai; Scott B. Jones; Markus Tuller

2011-01-01

326

Evaluation of the Ground-Water Contaminant Plume Extending from the 183-H Solar Evaporation Basins.  

National Technical Information Service (NTIS)

The 183-H Solar Evaporation Basins, located on the Hanford Site in southeastern Washington State, were used for solar concentration and storage of process wastes that consisted of nitric, sulfuric, and hydrofluoric acids, contaminated by heavy metals and ...

S. H. Hall

1989-01-01

327

Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process  

NASA Astrophysics Data System (ADS)

This paper shows an influence of evaporative cooler at the inlet of regeneration air stream of an adsorptive desiccant cooling process on the cooling/dehumidifying performance. This evaporative cooling was expected to cause humidity increase in regeneration air reducing the dehumidifying performance of the honeycomb absorber, while the evaporative cooling plays an important role to produce a lower temperature in supply air. Two different airs to be used for the regeneration of the desiccant wheel were considered. One was fresh outside air (OA mode) and the other was air ventilated from the room (RA mode). Experimental results showed that the amount of dehumidified water obtained at the process without water spray evaporative cooler was actually larger than that of process with water spray evaporative cooler. This behavior was mainly due to increase of humidity or relative humidity in the regeneration air as expected. However, temperature of supply air produced by the process with the evaporator was rather lower than that of the other because of the cooled return air, resulting higher CE value. Regarding the operating mode, the evaporative cooler at the OA-mode was no longer useful at higher ambient humidity because of the difficulty of the evaporation of the water in such high humidity. It was also found that its dehumidifying performance was remarkably decreased at higher ambient humidity and lower regeneration temperature since the effective adsorption capacity at the resulting high relative humidity of the regeneration air decreased.

Ando, Kosuke; Kodama, Akio; Hirose, Tsutomu; Goto, Motonobu; Okano, Hiroshi

328

Investigation of the process of liquid evaporation from a porous metal under vacuum conditions  

Microsoft Academic Search

The method and results of an investigation of the evaporation of water into a vacuum are described. The steady-state regime of evaporation in a porous metal is examined. The dependence of the evaporation rate on the parameters of the porous metal and the heat flux density has been experimentally determined. The temperature distribution in the porous plate is determined theoretically.

V. I. Balakhonova; P. A. Novikov; B. M. Smol'skii; V. V. Selivanov; V. N. Shmigora

1968-01-01

329

On the theory relating changes in area-average and pan evaporation (Invited)  

Microsoft Academic Search

Theory relating changes in area-average evaporation with changes in the evaporation from pans or open water is developed. Such changes can arise by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation that modify surface evaporation rates in the same direction, and Type (b) processes related to coupling between the surface and atmospheric boundary layer (ABL) at

W. Shuttleworth; A. Serrat-Capdevila; M. L. Roderick; R. Scott

2009-01-01

330

Hydrogen capacity and absorption rate of the SAES St707 non-evaporable getter at various temperatures.  

SciTech Connect

A prototype of a tritium thermoelectric generator (TTG) is currently being developed at Sandia. In the TTG, a vacuum jacket reduces the amount of heat lost from the high temperature source via convection. However, outgassing presents challenges to maintaining a vacuum for many years. Getters are chemically active substances that scavenge residual gases in a vacuum system. In order to maintain the vacuum jacket at approximately 1.0 x 10{sup -4} torr for decades, nonevaporable getters that can operate from -55 C to 60 C are going to be used. This paper focuses on the hydrogen capacity and absorption rate of the St707{trademark} non-evaporable getter by SAES. Using a getter testing manifold, we have carried out experiments to test these characteristics of the getter over the temperature range of -77 C to 60 C. The results from this study can be used to size the getter appropriately.

Hsu, Irving; Mills, Bernice E.

2010-08-01

331

Soil Evaporation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

332

Evaporation, Condensation, and Precipitation  

NSDL National Science Digital Library

After completion of this project students should have an understanding of evaporation, condensation, and precipitation in the water cycle. Use the websites provided to answer the questions. Record your answers on the spreadsheet provided. Do you understand how the water cycle works? Begin by watching this short video about the water cycle.water cycle video Use the website to define condensation, precipitation, and evaporation?water cycle List the different types of precipitation from the site.types of precipitation Follow the directions to the experiment on this website to get a better understanding of how evaporation takes ...

Brown, Miss

2009-10-21

333

On Maximum Evaporation Rates of Liquid Droplets in Rocket Motors 1  

Microsoft Academic Search

Upper lilllits have been estimated for the rate of evapo­ ration of slllall liquid droplets in representative rocket cOlllbustion challlbers. The droplets are assullled to be isotherlllal at all tillles. The droplet telllperature as a function of tillle is deterlllined by an appropriate heat balance. The calculations are useful in deterlllining the significance of inelastic collisions between liquid droplets for

S. S. PENNER

1953-01-01

334

The Case of the Disappearing Water  

NSDL National Science Digital Library

In this experiment, students investigate the evaporation of water as part of a solution to a simulated mystery. They will compare rates of evaporation under different conditions, demonstrate knowledge of the concepts of evaporation, and be able to explain evaporation in the context of the water cycle.

335

Reservoir evaporation in central Colorado  

USGS Publications Warehouse

Evaporation losses from seven reservoirs operated by the Denver Water Department in central Colorado were determined during various periods from 1974 to 1980. The reservoirs studies were Ralston, Cheesman, Antero, Williams Fork, Elevenmile Canyon, Dillon, and Gross. Energy-budget and mass-transfer methods were used to determine evaporation. Class-A pan data also were collected at each reservoir. The energy-budget method was the most accurate of the methods used to determine evaporation. At Ralston, Cheesman, Antero, and Williams Fork Reservoirs the energy-budget method was used to calibrate the mass-transfer coefficients. Calibrated coefficients already were available for Elevenmile Canyon, Dillon, and Gross Reservoirs. Using the calibrated coefficients, long-term mass-transfer evaporation rates were determined. Annual evaporation values were not determined because the instrumentation was not operated for the entire open-water season. Class-A pan data were used to determine pan coefficients for each season at each reservoir. The coefficients varied from season to season and between reservoirs, and the seasonal values ranged from 0.29 to 1.05. (USGS)

Spahr, N. E.; Ruddy, B. C.

1983-01-01

336

Trace Elements and Petroleum Hydrocarbons in the Aquatic Bird Food Chain Of Process Water Evaporation Ponds at the Little American Refinery, Casper, Wyoming.  

National Technical Information Service (NTIS)

This study determined the nature and extent of trace elements, metals, and petroleum hydrocarbons in evaporation ponds used for the disposal of process water from Sinclair Oil Corporations LARCO oil refinery in Evansville, Wyoming. This study was conducte...

P. Ramirez

2008-01-01

337

Formation of Nitrogen- and Sulfur-Containing Light-Absorbing Compounds Accelerated by Evaporation of Water from Secondary Organic Aerosols  

SciTech Connect

Aqueous extracts of secondary organic aerosols (SOA) generated from the ozonolysis of dlimonene were subjected to dissolution, evaporation, and re-dissolution in the presence and absence of ammonium sulfate (AS). Evaporation with AS at pH 4-9 produced chromophores that were stable with respect to hydrolysis and had a distinctive absorption band at 500 nm. Evaporation accelerated the rate of chromophore formation by at least three orders of magnitude compared to the reaction in aqueous solution, which produced similar compounds. Absorption spectroscopy and high-resolution nanospray desorption electrospray ionization (nano-DESI) mass spectrometry experiments suggested that the molar fraction of the chromophores was small (< 2%), and that they contained nitrogen atoms. Although the colored products represented only a small fraction of SOA, their large extinction coefficients (>10{sup 5} L mol{sup -1} cm{sup -1} at 500 nm) increased the effective mass absorption coefficient of the residual organics in excess of 10{sup 3} cm{sup 2} g{sup -1} - a dramatic effect on the optical properties from minor constituents. Evaporation of SOA extracts in the absence of AS resulted in the production of colored compounds only when the SOA extract was acidified to pH {approx} 2 with sulfuric acid. These chromophores were produced by acid-catalyzed aldol condensation, followed by a conversion into organosulfates. The presence of organosulfates was confirmed by high resolution mass spectrometry experiments. Results of this study suggest that evaporation of cloud or fog droplets containing dissolved organics leads to significant modification of the molecular composition and serves as a potentially important source of light-absorbing compounds.

Nguyen, Tran B.; Lee, Paula B.; Updyke, Katelyn M.; Bones, David L.; Laskin, Julia; Laskin, Alexander; Nizkorodov, Sergey

2012-01-14

338

Formation of nitrogen- and sulfur-containing light-absorbing compounds accelerated by evaporation of water from secondary organic aerosols  

NASA Astrophysics Data System (ADS)

Aqueous extracts of secondary organic aerosols (SOA) generated from the ozonolysis of d-limonene were subjected to dissolution, evaporation, and re-dissolution in the presence and absence of ammonium sulfate (AS). Evaporation with AS at pH 4-9 produced chromophores that were stable with respect to hydrolysis and had a distinctive absorption band at 500 nm. Evaporation accelerated the rate of chromophore formation by at least three orders of magnitude compared to the reaction in aqueous solution, which produced similar compounds. Absorption spectroscopy and high-resolution nanospray desorption electrospray ionization (nano-DESI) mass spectrometry experiments suggested that the molar fraction of the chromophores was small (<2%), and that they contained nitrogen atoms. Although the colored products represented only a small fraction of SOA, their large extinction coefficients (>105 L mol-1 cm-1 at 500 nm) increased the effective mass absorption coefficient of the residual organics in excess of 103 cm2 g-1 - a dramatic effect on the optical properties from minor constituents. Evaporation of SOA extracts in the absence of AS resulted in the production of colored compounds only when the SOA extract was acidified to pH ˜ 2 with sulfuric acid. These chromophores were produced by acid-catalyzed aldol condensation, followed by a conversion into organosulfates. The presence of organosulfates was confirmed by high resolution mass spectrometry experiments. Results of this study suggest that evaporation of cloud or fog droplets containing dissolved organics leads to significant modification of the molecular composition and serves as a potentially important source of light-absorbing compounds.

Nguyen, Tran B.; Lee, Paula B.; Updyke, Katelyn M.; Bones, David L.; Laskin, Julia; Laskin, Alexander; Nizkorodov, Sergey A.

2012-01-01

339

Wetting mode transition of nanoliter scale water droplets during evaporation on superhydrophobic surfaces with random roughness structure  

NASA Astrophysics Data System (ADS)

During evaporation, shape changes of nanoliter-scale (80-100 nL) water droplets were evaluated on two superhydrophobic surfaces with different random roughness (nm-coating, ?m-coating). The square of the contact radius and the square of the droplet height decreased linearly with evaporation time. However, trend changes were observed at around 170 s (nm-coating) and around 150 s (?m-coating) suggesting a wetting mode transition. The calculated droplet radii for the wetting mode transition from the average roughness distance and the average roughness height of these surface structures were approximately equal to the experimental values at these trend changes. A certain level of correlation between the roughness size and droplet radius at the wetting mode transition was confirmed on surfaces with random roughness.

Furuta, Tsutomu; Isobe, Toshihiro; Sakai, Munetoshi; Matsushita, Sachiko; Nakajima, Akira

2012-01-01

340

Instrument for Measuring Evaporation.  

National Technical Information Service (NTIS)

An evaporation rate meter, or evaporimeter, has been devised that shows promise of directly measuring the rate of evaporation near the sea surface. The simplicity of the instrument indicates that it may be of interest to oceanographers, and possibly to me...

A. H. Schooley

1965-01-01

341

Quantitative evaluation of evaporation rate during spin-coating of polymer blend films: Control of film structure through defined-atmosphere solvent-casting.  

PubMed

Thin films of polymer mixtures made by spin-coating can phase separate in two ways: by forming lateral domains, or by separating into distinct layers. The latter situation (self-stratification or vertical phase separation) could be advantageous in a number of practical applications, such as polymer optoelectronics. We demonstrate that, by controlling the evaporation rate during the spin-coating process, we can obtain either self-stratification or lateral phase separation in the same system, and we relate this to a previously hypothesised mechanism for phase separation during spin-coating in thin films, according to which a transient wetting layer breaks up due to a Marangoni-type instability driven by a concentration gradient of solvent within the drying film. Our results show that rapid evaporation leads to a laterally phase-separated structure, while reducing the evaporation rate suppresses the interfacial instability and leads to a self-stratified final film. PMID:21086015

Mokarian-Tabari, P; Geoghegan, M; Howse, J R; Heriot, S Y; Thompson, R L; Jones, R A L

2010-11-18

342

A molecular beam study of the evaporation of water from a liquid jet  

Microsoft Academic Search

A method to maintain a clean surface of a liquid in a high vacuum is described. Using a very thin and fast liquid jet it is not only possible to prevent freezing of the liquid but also to reduce the number of collisions between evaporating molecules to negligibly small values. Thus many of the standard, vacuum dependent, particle probing techniques

M. Faubel; S. Schlemmer; J. P. Toennies

1988-01-01

343

Export Rates of North Atlantic Deep Water  

NASA Astrophysics Data System (ADS)

The concept from Bolin and Rhode (1973) of transit time distributions (TTDs)newline for reservoirs is applied to North Atlantic Deep Water (NADW) in the subpolar North Atlantic. The reservoirs are the different density classes of NADW, i.e. Upper Labrador Sea Water (ULSW), Labrador Sea Water (LSW), Gibbs Fracture Zone Water(GFZW) and Denmark Strait Overflow Water (DSOW). The TTDs for these reservoirs are computed as volume integral of pointwise TTDs, which are inferred from CFC data collected between 1997 and 2005. It will be discussed, in how far these TTDs and their temporal derivatives can be used to infer ventilation and export rates for NADW. These results will be compared with direct observational data, e.g. the export of NADW from the subpolar North Atlantic in the deep western boundary current as reported in Schott et al. (2006). Bolin, B., and H. Rohde, A note on the concepts of age distribution and transit time in natural reservoirs, Tellus XXV, 1, 1973. Schott, F. A., J. Fischer, M. Dengler, and R. Zantopp,Variability of the Deep Western Boundary Current east of the Grand Banks, Geophys. Res. Lett., 33, L21S07, doi:10.1029/2006GL026563, 2006.

Steinfeldt, R.; Rhein, M.

2009-04-01

344

Vapor compression evaporator concentrates, recovers alcohol  

SciTech Connect

This article focuses on presenting a solution to the high energy cost of operating a steam heated, single effect evaporator used by Monsanto Industrial Chemical Company at a plant in Seattle, Wash., to produce vanillin from pulp and paper mill sulfite. Use of the single effect flash evaporator resulted in high energy usage due not only to the ''single effect'' use of steam, but also because energy consumption was reduced only slightly at low operating rates. The solution to this problem was the replacement of the single effect evaporator with a vapor recompression evaporator. Operating for over 1 1/2 years, the vapor recompression evaporator system has had no significant maintenance problems. The system operates with only 1/60th the steam consumption and 15% of the total energy consumption of the previous evaporator and has had no tube fouling. Also, since the distillate is condensed within the evaporator, less cooling water is required, allowing two heat exchangers to be taken out of service. When operating at less than design capacity, the energy consumption drops almost linearly with the feed rate. At low feed rates, a by-pass valve unloads the compressor to reduce energy consumption. Total energy consumption, now 15% of the previous level, results in an estimated pay-back of less than three years.

Miller, M.N. (Monsanto, Seattle); Robe, K.; Bacchetti, J.A.

1982-11-01

345

Effect of nitrogen flow rate on the properties of TiN film deposited by e beam evaporation technique  

NASA Astrophysics Data System (ADS)

In this work, titanium nitride (TiN) films have been deposited by e beam evaporation technique on Si/SiO2 (1 0 0) substrates at room temperature. The influence of nitrogen flow rate (N2 = 0, 4, 6, 8 and 10 sccm (standard cubic centimeter per minute)) on the structural, morphological and electrical properties of the TiN films has been studied. The deposited TiN films have been characterized using X-ray diffraction (XRD), XPS (X-ray photoelectron spectroscopy), FESEM (Field emission scanning electron microscopy) and four-point probe resistivity measurement techniques. XRD patterns reveal FCC symmetry of the film with (1 1 1) preferred orientations for Ti film (N2 = 0 sccm) and (2 0 0) preferred orientations for TiN film (N2 = 4, 6, 8 and 10 sccm), respectively. The lattice parameters for TiN films are found to increase from 4.237 Å to 4.239 Å with the increase in nitrogen flow rate. The presence of different phases such as TiN, TiON and TiO2 were confirmed by XPS analysis. The FESEM images of the TiN films showed a smooth morphology with columnar grain structures. The grain size of the TiN films was found to increase as the nitrogen flow rate was increased from 4 to 10 sccm. The electrical resistivity measurement showed that the resistivity of the film decreased from 333 ?? cm to 111 ?? cm on increasing nitrogen flow rate from 4 to10 sccm.

Arshi, Nishat; Lu, Junqing; Koo, Bon Heun; Lee, Chan Gyu; Ahmed, Faheem

2012-09-01

346

Numerical modeling studies on the alternately pulsed infiltration and subsequent evaporation of water in a dry high desert alluvial soil  

SciTech Connect

The concept of no liquid-phase migration of low-level radionuclides is extremely important for the U.S. Department of Energy, Nevada Operations Office (USDOE/NV) Low-Level Radioactive Waste Management Sites (RWMS) in Areas 3 and 5 of the Nevada Test Site (NTS). Each site location is situated in an area known for its dry conditions. A series of computer modeling problems were set up to study the effects of pulsing the desert surface with large amounts of water, followed by intense evaporative conditions. The pulsed-water scenarios were run using an in-house model, named {open_quotes}ODRECHB,{close_quotes} which is briefly described. ODRECHB is particularly adapted to model the dry desert alluvium and extreme evaporative conditions found at NTS. Comparable results were obtained using the well known Battelle NW code {open_quotes}UNSAT-H 2.0,{close_quotes} by Fayer and Jones. The realistic-to-overly conservative water applications to a bare soil surface did not cause water to infiltrate below ten meters. The results are shown on the accompanying video tape.

Cawlfield, D.E.; Lindstrom, F.T.; Weaver, H.

1993-12-31

347

Mixed feed evaporator  

DOEpatents

In the preparation of the gaseous reactant feed to undergo a chemical reaction requiring the presence of steam, the efficiency of overall power utilization is improved by premixing the gaseous reactant feed with water and then heating to evaporate the water in the presence of the gaseous reactant feed, the heating fluid utilized being at a temperature below the boiling point of water at the pressure in the volume where the evaporation occurs.

Vakil, Himanshu B. (Schenectady, NY); Kosky, Philip G. (Ballston Lake, NY)

1982-01-01

348

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, January 1March 31, 1993  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable climatic conditions.

J. Boysen; J. Morotti

1993-01-01

349

Evaluation of the freeze-thaw\\/evaporation process for the treatment of produced waters. Quarterly technical progress report, April 1June 30, 1993  

Microsoft Academic Search

Water purification by using natural conditions to promote freezing appears to be an extremely attractive natural conditions freeze-crystallization process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions with favorable

J. Boysen; J. Morotti

1993-01-01

350

Experimental Method for Determination of the Rate of Evaporation of 2,4,6-Trinitrotoluene (TNT) and 2,4-Dinitrotoluene (2,4-DNT).  

National Technical Information Service (NTIS)

The rate of evaporation of 1,3,5-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) into air under ambient conditions was determined. This was accomplished by making cast pipes of TNT and 2,4-DNT. Nitrogen was passed through a pipe and then through a cold...

A. B. Rosencrance E. E. Brueggemann

1993-01-01

351

The non-equilibrium factor and the flashing evaporation rate inside the flash chamber of a multi-stage flash desalination plant  

Microsoft Academic Search

A study was undertaken to measure the non-equilibrium factor and to correlate the flashing evaporation rate inside the flash chamber of a multi-stage flash (MSF) desalination plant. A computer code was developed to quantitatively simulate the MSF desalination plant operation and solve the mass, heat and salt balance equations. The simulator was tested against an MSF pilot plant with a

Hassan E. S. Fath

1997-01-01

352

EFFECT OF UTILIZING EVAPORATIVE COOLING IN TIESTALL DAIRY BARNS EQUIPPED WITH TUNNEL VENTILATION ON RESPIRATION RATES AND BODY TEMPERATURE OF LACTATING DAIRY CATTLE  

Microsoft Academic Search

During the summer of 2001, six tie-stall dairy barns in northeast Missouri were monitored to determine the effects of evaporative cooling on the environment, respiration rate and body temperature of lactating dairy cattle housed in barns equipped with tunnel ventilation. Temperature and relative humidity were continuously monitored and recorded every 15 minutes in six barns (3 with and 3 without

M. J. Brouk; J. F. Smith; J. P. Harner

353

Evaporation from the shallow Lake Massaciuccoli (Tuscany, Italy) studied using stable isotopes and evaporation pan data  

NASA Astrophysics Data System (ADS)

Oxygen and hydrogen isotope variations monitored in Lake Massaciuccoli (7 km2, 2 m deep, seasonally variable water level) during summer 2008, were compared with those observed in a Class A evaporation pan (diameter 120.6 cm, depth 25.4 cm) placed on the lake eastern shore. Air temperature, pressure, relative humidity, wind speed and direction, solar radiation, water temperature in the lake and the pan were also measured. The pluviometer indicated that no precipitation occurred during the study period. The pan was initially filled with groundwater up to the level of 19.2 cm (219 L), depleted in heavy isotopes with respect to tha lake water. Sodium chloride was added up to the concentration of 1 g×L-1, which is assumed do not affect significantly the evaporation rate till the water volume is reduced to less than 10 %. The Cl- concentration was used to provide an estimation of the evaporated water fraction, in addition to the micrometer measuring the water level variations. The pan water was sampled every 2-3 days and Cl- and stable isotopes determined. The set of stable isotope and evaporation data enabled us to compute the parameters governing the evaporation process and the isotopic exchanges with the atmospheric moisture, according to the procedure proposed by Gonfiantini (1986). The values were applied to test three working hypotheses of water balance of Lake Massaciuccoli: (i) surface inflow and outflow of liquid water are negligible and only evaporation is important; (ii) the inflow is negligible and outflow and evaporation are both significant; (iii) the three terms of balance are all important but the losses by evaporation and outflow exceed inflow (as the lake water level was decreasing). Water exchanges with groundwater are considered negligible. The best agreement between lake and pan data was obtained with the second hypothesis, for which the fraction of water removed by evaporation was estimated to be about 40 % ot he total water losses. This residual 60 % of losses consists essentially of water pumped from the lake for irrigation, in rough agreement with independent estimations. In the final stages of pan water evaporation, the well known hook trend of heavy isotope delta values versus residual water fraction was observed. The data elaboration is being continued and refined. Correction factors for the so called pan effect will also be applied. Collection of atmospheric vapour samples has been started. R. Gonfiantini, 1986. Isotopes in lake studies, in Handbook of Environmental Isotope Geochemistry (P. Fritz and J-Ch. Fontes, Eds.), Vol. 2, pp.113-168.

Baneschi, I.; Gonfiantini, R.; Guidi, M.

2009-04-01

354

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Final report, August 1992--August 1996  

SciTech Connect

The use of freeze-crystallization is becoming increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year round in regions where subfreezing temperatures seasonally occur. The climates typical of Colorado`s San Juan Basin and eastern slope, as well as the oil and gas producing regions of Wyoming, are well suited for application of these processes in combination. Specifically, the objectives of this research are related to the development of a commercially-economic FTE (freeze-thaw/evaporation) process for the treatment and purification of water produced in conjunction with oil and natural gas. The research required for development of this process consists of three tasks: (1) a literature survey and process modeling and economic analysis; (2) laboratory-scale process evaluation; and (3) field demonstration of the process. Results of research conducted for the completion of these three tasks indicate that produced water treatment and disposal costs for commercial application of the process, would be in the range of $0.20 to $0.30/bbl in the Rocky Mountain region. FTE field demonstration results from northwestern New Mexico during the winter of 1995--96 indicate significant and simultaneous removal of salts, metals, and organics from produced water. Despite the unusually warm winter, process yields demonstrate disposal volume reductions on the order of 80% and confirm the potential for economic production of water suitable for various beneficial uses. The total dissolved solids concentrations of the FTE demonstration streams were 11,600 mg/L (feed), 56,900 mg/L (brine), and 940 mg/L (ice melt).

Boysen, J.E.; Walker, K.L.; Mefford, J.L.; Kirsch, J.R. [Resource Technology Corp., Laramie, WY (United States); Harju, J.A. [North Dakota Univ., Grand Forks, ND (United States). Energy and Environmental Research Center

1996-06-01

355

Influence of evaporation, ground water, and uncertainty in the hydrologic budget of Lake Lucerne, a seepage lake in Polk County, Florida  

USGS Publications Warehouse

A detailed hydrologic budget was constructed of a seepage lake of sinkhole origin in the karst terrain of central Florida. During the drought period studied, lake evaporation computed by the energy-budget and mass-transfer methods was the largest component in the budget, followed by rainfall. Ground-water inflow contributed about one-third of the total inflow. Lake leakage was about one-fourth of the evaporative losses and was increased substantially by pumping from the Upper Floridan aquifer.

Lee, Terrie Mackin; Swancar, Amy

1997-01-01

356

Water-quality and sediment-chemistry data of drain water and evaporation ponds from Tulare Lake Drainage District, Kings County, California March 1985 to March 1986  

USGS Publications Warehouse

Trace element and major ion concentrations were measured in water samples collected monthly between March 1985 and March 1986 at the MD-1 pumping station at the Tulare Lake Drainage District evaporation ponds, Kings County, California. Samples were analyzed for selected pesticides several times during the year. Salinity, as measured by specific conductance, ranged from 11,500 to 37,600 microsiemens/centimeter; total recoverable boron ranged from 4,000 to 16,000 micrg/L; and total recoverable molybdenum ranged from 630 to 2,600 microg/L. Median concentrations of total arsenic and total selenium were 97 and 2 microg/L. Atrazine, prometone, propazine, and simazine were the only pesticides detected in water samples collected at the MD-1 pumping station. Major ions, trace elements, and selected pesticides also were analyzed in water and bottom-sediment samples from five of the southern evaporation ponds at Tulare Lake Drainage District. Water enters the ponds from the MD-1 pumping station at pond 1 and flows through the system terminating at pond 10. The water samples increased in specific conductance (21,700 to 90,200 microsiemens/centimeter) and concentrations of total arsenic (110 to 420 microg/L), total recoverable boron (12,000 to 80,000 microg/L) and total recoverable molybdenum (1,200 to 5,500 microg/L) going from pond 1 to pond 10, respectively. Pesticides were not detected in water from any of the ponds sampled. Median concentrations of total arsenic and total selenium in the bottom sediments were 4.0 and 0.9 microg/g, respectively. The only pesticides detected in bottom sediment samples from the evaporation ponds were DDD and DDE, with maximum concentration of 0.8 microg/kilogram. (Author 's abstract)

Fujii, Roger

1988-01-01

357

Interannual variability in the surface energy budget and evaporation over a large southern inland water in the United States  

NASA Astrophysics Data System (ADS)

Understanding how the surface energy budget and evaporation over inland waters respond to climate change and variability remains limited. Here we report 2 year measurements of the surface energy budget using the eddy covariance method over Ross Barnett Reservoir, Mississippi, USA, for 2008 and 2009. Annual mean sensible (H) and latent (LE) heat fluxes in 2008 were 9.5%, and 10.0% greater than in 2009, respectively. Most of the interannual variations in the surface energy fluxes and meteorological variables primarily occurred in the cool seasons from October to March, which was enhanced by frequent large wind events associated with cold front passages. These large wind events greatly promoted H and LE exchange and produced H and LE pulses that increased variations in H and LE between these two cool seasons. In the warm seasons from April to September, H and LE pulses were also present, which largely increased variations in LE and dampened those in H between the two warm seasons. The H and LE pulses contributed to approximately 50% of the annual H and 28% of the annual LE, although they only covered about 16% of the entire year. The interannual variations in H and LE pulses contributed to about 78% of the interannual variations in H and 40% of those in LE. Our results imply that the increased interannual variability in cold front activities as a result of climate change would amplify interannual variations in the evaporation and the surface energy exchange over inland waters in this region.

Zhang, Qianyu; Liu, Heping

2013-05-01

358

Evaporative estimation using data fusion  

Microsoft Academic Search

This paper present evaporative estimation of water using data fusion technique. There are many factors in evaporative locating process that provided for consideration together. So this paper will be study about factors with concerning in meteorology that influential to evaporation and explained about relation of these factors by statistical method. The used data obtained from Thai Meteorological Department which collects

P. Roengruen; V. Tipsuwannaporn; A. Numsomran; Sh. Harnnarong

2008-01-01

359

Involvement of root ABA and hydraulic conductivity in the control of water relations in wheat plants exposed to increased evaporative demand.  

PubMed

We studied the possible involvement of ABA in the control of water relations under conditions of increased evaporative demand. Warming the air by 3°C increased stomatal conductance and raised transpiration rates of hydroponically grown Triticum durum plants while bringing about a temporary loss of relative water content (RWC) and immediate cessation of leaf extension. However, both RWC and extension growth recovered within 30 min although transpiration remained high. The restoration of leaf hydration and growth were enabled by increased root hydraulic conductivity after increasing the air temperature. The use of mercuric chloride (an inhibitor of water channels) to interfere with the rise on root hydraulic conductivity hindered the restoration of extension growth. Air warming increased ABA content in roots and decreased it in shoots. We propose this redistribution of ABA in favour of the roots which increased the root hydraulic conductivity sufficiently to permit rapid recovery of shoot hydration and leaf elongation rates without the involvement of stomatal closure. This proposal is based on known ability of ABA to increase hydraulic conductivity confirmed in these experiments by measuring the effect of exogenous ABA on osmotically driven flow of xylem sap from the roots. Accumulation of root ABA was mainly the outcome of increased export from the shoots. When phloem transport in air-warmed plants was inhibited by cooling the shoot base this prevented ABA enrichment of the roots and favoured an accumulation of ABA in the shoot. As a consequence, stomata closed. PMID:20924765

Kudoyarova, Guzel; Veselova, Svetlana; Hartung, Wolfram; Farhutdinov, Rashit; Veselov, Dmitry; Sharipova, Guzyal

2010-10-06

360

Differing source water inputs, moderated by evaporative enrichment, determine the contrasting ?18OCELLULOSE signals in maritime Antarctic moss peat banks  

NASA Astrophysics Data System (ADS)

Oxygen isotope palaeoclimate records, preserved in moss tissue cellulose, are complicated by environmental influences on the relationships between source water inputs and evaporative conditions. We carried out stable isotope analyses of precipitation collected from the maritime Antarctic and cellulose extracted from co-located Chorisodontium aciphyllum dominated moss peat bank deposits accumulated since 1870 A.D. Analyses of stable oxygen and hydrogen isotope composition of summer precipitation on Signy Island (60.7°S, 45.6°W) established a local meteoric water line (LMWL) similar to both the global MWL and other LMWLs, and almost identical to the HadAM3 isotope-enabled global circulation model output. The oxygen isotopic composition of cellulose (?18OC) revealed little temporal variation between four moss peat banks on Signy Island since 1870. However, ?18OC followed two patterns with Sites A and D consistently 3‰ enriched relative to ?18OC values from Sites B and C. The growing moss surfaces at Sites A and D are likely to have been hydrated by isotopically heavier summer precipitation, whilst at Sites B and C, the moss banks are regularly saturated by the isotopically depleted snow melt streams. Laboratory experiments revealed that evaporative enrichment of C. aciphyllum moss leaf water by 5‰ occurred rapidly following saturation (ecologically equivalent to post-rainfall or snow melt periods). In addition to the recognized source water-cellulose fractionation extent of 27 ± 3‰, such a shift would account for the 32‰ difference measured between ?18O of Signy Island precipitation and cellulose.

Royles, Jessica; Sime, Louise C.; Hodgson, Dominic A.; Convey, Peter; Griffiths, Howard

2013-03-01

361

Fallow soil evaporation and water storage as affected by stubble in sub-humid (Argentina) and semi-arid (Australia) environments  

Microsoft Academic Search

The effect of stubble mulch on soil water storage during fallow is highly variable. In environments with low rainfall and coarse-textured soil, contribution of stubble to gains in water storage is often smaller than in wetter environments with heavier soil. While this pattern is recognised, the effect of rainfall, evaporative demand and soil remains confounded.This paper investigates the effect of

J. P. Monzon; V. O. Sadras; F. H. Andrade

2006-01-01

362

Development of synchronized, autonomous, and self-regulated oscillations in transpiration rate of a whole tomato plant under water stress  

PubMed Central

Plants respond to many environmental changes by rapidly adjusting their hydraulic conductivity and transpiration rate, thereby optimizing water-use efficiency and preventing damage due to low water potential. A multiple-load-cell apparatus, time-series analysis of the measured data, and residual low-pass filtering methods were used to monitor continuously and analyse transpiration of potted tomato plants (Solanum lycopersicum cv. Ailsa Craig) grown in a temperature-controlled greenhouse during well-irrigated and drought periods. A time derivative of the filtered residual time series yielded oscillatory behaviour of the whole plant's transpiration (WPT) rate. A subsequent cross-correlation analysis between the WPT oscillatory pattern and wet-wick evaporation rates (vertical cotton fabric, 0.14 m2 partly submerged in water in a container placed on an adjacent load cell) revealed that autonomous oscillations in WPT rate develop under a continuous increase in water stress, whereas these oscillations correspond with the fluctuations in evaporation rate when water is fully available. The relative amplitude of these autonomous oscillations increased with water stress as transpiration rate decreased. These results support the recent finding that an increase in xylem tension triggers hydraulic signals that spread instantaneously via the plant vascular system and control leaf conductance. The regulatory role of synchronized oscillations in WPT rate in eliminating critical xylem tension points and preventing embolism is discussed.

Wallach, Rony; Da-Costa, Noam; Raviv, Michael; Moshelion, Menachem

2010-01-01

363

Spatial Variation of "Non-Rainfall" Water Input and the Effect of Mechanical Soil Crusts on Input and Evaporation  

NASA Astrophysics Data System (ADS)

"Non-rainfall" water is important to the soil water balance and ecology of arid ecosystems. A component of this "non-rainfall" water in the Namib Desert, fog, exhibits spatial variation implying variability in composition and significance of each vector (dew, fog, vapour adsorption) to ecology at different locations. The composition of "non -rainfall" water input directly into soil was investigated at two sites in the Central Namib Desert, Kleinberg and Gobabeb. Results showed spatial variation in composition between the sites, although vapour adsorption dominated input at both sites. Fog contributed more to total "non rainfall" atmospheric water closer to the coast (Kleinberg) compared to further inland (Gobabeb) but was lower than expected at both sites. Absolute values of fog input at both sites showed the opposite trend, Kleinberg 0.38 mm per night compared to Gobabeb 8.7 mm per night. This difference was attributed to the development of a mechanical crust on the soil surface at Kleinberg, which resulted in a significant reduction of vapour adsorption compared to Gobabeb. The crust also led to a significant reduction in evaporation from the sample at Kleinberg compared to the one at Gobabeb. Ecological differences between the two sites can be attributed to the development of the soil crust on the sample at Kleinberg and not on the sample at Gobabeb.

Kaseke, K. F.; Mills, A. J.; Esler, K.; Henschel, J.; Seely, M. K.; Brown, R.

2012-12-01

364

Water-quality and sediment-chemistry data of drain water and evaporation ponds from Tulare Lake Drainage District, Kings County, California, March 1985 to March 1986  

SciTech Connect

Trace element and major ion concentrations were measured in water samples collected monthly between March 1985 and March 1986 at the MD-1 pumping station at the Tulare Lake Drainage District evaporation ponds, Kings County, California. Samples were analyzed for selected pesticides several times during the year. Salinity, as measured by specific conductance, ranged from 11,500 to 37,600 microsiemens/centimeter; total recoverable boron ranged from 4,000 to 16,000 micrg/L; and total recoverable molybdenum ranged from 630 to 2,600 microg/L. Median concentrations of total arsenic and total selenium were 97 and 2 microg/L. Atrazine, prometone, propazine, and simazine were the only pesticides detected in water samples collected at the MD-1 pumping station. Major ions, trace elements, and selected pesticides also were analyzed in water and bottom-sediment samples from five of the southern evaporation ponds at Tulare Lake Drainage District. The water samples increased in specific conductance and concentrations of total arsenic, total recoverable boron and total recoverable molybdenum going from pond 1 to pond 10, respectively. Median concentrations of total arsenic and total selenium in the bottom sediments were 4.0 and 0.9 microg/g, respectively. 6 refs., 2 figs., 12 tabs.

Fujii, R.

1988-01-01

365

Daily Energy-Budget and Penman Evaporation From Upper Klamath Lake, Oregon  

Microsoft Academic Search

To better constrain the hydrologic budget of Upper Klamath Lake, open-water evaporation rates were calculated on a daily basis from 7-June-03 to 30-September-03 using the energy-budget method. Results show evaporation rates to range from as low as -0.8 mm d-1 to as high as 10.2 mm d-1 with an overall average of 4.5 mm d-1. Monthly evaporation totals compared to

K. D. Janssen; M. L. Cummings

2005-01-01

366

Energy Budget Evaporation From Williams Lake: A Closed Lake in North Central Minnesota  

Microsoft Academic Search

Evaporation from Williams Lake, computed by the energy budget method for the five open-water seasons of 1982-1986, varied from a maximum seasonal rate of 0.282 cm\\/d in 1983 to a minimum seasonal rate of 0.219 cm\\/d in 1982. The pattern of monthly values of evaporation is not consistent from year to year. The normally expected pattern of low evaporation values

A. M. Sturrock; T. C. Winter; D. O. Rosenberry

1992-01-01

367

Energy budget evaporation from Williams Lake: A closed lake in north central Minnesota  

Microsoft Academic Search

Evaporation from Williams Lake, computed by the energy budget method for the five open-water seasons of 1982–1986, varied from a maximum seasonal rate of 0.282 cm\\/d in 1983 to a minimum seasonal rate of 0.219 cm\\/d in 1982. The pattern of monthly values of evaporation is not consistent from year to year. The normally expected pattern of low evaporation values

A. M. Sturrock; T. C. Winter; D. O. Rosenberry

1992-01-01

368

Cracks as Evidence for Water Evaporation and Condensation Associated with Temperature Changes in Hydrous Sulfate Sands  

Microsoft Academic Search

Mineral-atmospheric water cycling promotes crack formation in the hydrous sulfate (gypsum) sands at White Sands National Monument, New Mexico. A similar water cycling process may promote crack formation in sulfate outcrops on Meridiani Planum, Mars.

G. V. Chavdarian; D. Y. Sumner

2007-01-01

369

Evaporation and canopy characteristics of coniferous forests and grasslands  

Microsoft Academic Search

Canopy-scale evaporation rate (E) and derived surface and aerodynamic conductances for the transfer of water vapour (gs and ga, respectively) are reviewed for coniferous forests and grasslands. Despite the extremes of canopy structure, the two vegetation types have similar maximum hourly evaporation rates (Emax) and maximum surface conductances (gsmax) (medians = 0.46 mm h-1 and 22 mm s-1). However, on

F. M. Kelliher; R. Leuning; E. D. Schulze

1993-01-01

370

Surface geometry and stomatal conductance effects on evaporation from aquatic macrophytes  

Microsoft Academic Search

Evaporative water loss rates of several floating and emergent aquatic macrophytes were studied over a 4-year period through comparison of daily evaporative water losses from similar-sized vegetated (E) and open water (E0) surfaces. Two species with planate floating leaves (water fern and water lily) yielded E\\/E0 values of 0.90 for one and four growing seasons, respectively, and displayed stomatal regulation

Michael G. Anderson; Sherwood B. Idso

1987-01-01

371

Evaporation of ice in planetary atmospheres - Ice-covered rivers on Mars  

Microsoft Academic Search

The existence of ice covered rivers on Mars is considered. It is noted that the evaporation rate of water ice on the surface of a planet with an atmosphere involves an equilibrium between solar heating and radiative and evaporative cooling of the ice layer. It is determined that even with a mean Martian insolation rate above the ice of approximately

D. Wallace; C. Sagan

1979-01-01

372

Spent-fuel pool thermal hydraulics: The evaporation question  

SciTech Connect

Many nuclear power plants are currently using dense fuel arrangements that increase the number of spent fuel elements stored in their spent-fuel pools (SFPs). The denser spent-fuel storage results in higher water temperatures, especially when certain event scenarios are analyzed. In some of these event scenarios, it is conservative to maximize the evaporation rate, while in other circumstances it is required to minimize the evaporation rates for conservatism. Evaporation is such a fundamental phenomenon that many branches of engineering developed various equations based on theory and experiments. The evaporation rates predicted by existing equations present a wide range of variation, especially at water temperatures >40{degrees}C. Furthermore, a study on which equations provide the highest and lowest evaporation rates has not been done until now. This study explores the sensitivity of existing evaporation equations to various parameters and recommends the limiting evaporation equations for use in the solution of SFP thermal problems. Note that the results of this study may be applicable to a much wider range of applications from irrigation ponds, cooling lakes, and liquid-waste management to calculating adequate air exchange rate for swimming pools and health spas.

Yilmaz, T.P. [Belcan Services, Lombard, IL (United States); Lai, J.C. [Public Service Electric & Gas Co., Berwick, PA (United States)

1996-12-31

373

Numerical investigation of the role of non-uniform evaporation rate in initiating Marangoni convection in capillary tubes  

Microsoft Academic Search

A computational model is developed to describe convection in volatile liquids evaporating in capillary tubes. Experimental work has demonstrated the existence of such convective structures. The correlation between this convection and the phase change process has been experimentally established. Temperature distribution on the liquid-vapour interface is considered in order to characterise the minimum of radial temperature gradient required to initiate

R. Bennacer; K. Sefiane; M. El-Ganaoui; C. Buffone

2004-01-01

374

Time-Resolved Evaporation Rate of Attoliter Glycerine Drops Using On-Chip CMOS Mass Sensors Based on Resonant Silicon Micro Cantilevers  

Microsoft Academic Search

The time-resolved evaporation rate of small glycerine drops (in the attoliter range) is determined by means of a mass sensor based on a resonant cantilever integrated in a CMOS chip. The cantilever is fabricated on crystalline silicon, using silicon-on-insulator (SOI) substrates for the integration of the CMOS-MEMS. Glycerine drops are deposited at the free end of the cantilever. The high

Maria Villarroya GaudÓ; Gabriel Abadal; Jaume Verd; Jordi Teva; Francesc Pérez-Murano; Eduardo Figueras Costa; Josep Montserrat; Arantxa Uranga; Jaume Esteve; Núria Barniol

2007-01-01

375

Cosolvent Evaporation Method for Enhancement of Solubility and Dissolution Rate of Poorly Aqueous Soluble Drug Simvastatin: In vitro – In vivo Evaluation  

Microsoft Academic Search

A number of synthesized chemical molecules suffer from low aqueous solubility problems. Enhancement of aqueous solubility,\\u000a dissolution rate, and bioavailability of drug is a very challenging task in drug development. In the present study, solubility\\u000a and dissolution of poorly aqueous soluble drug simvastatin (SIM) was enhanced using hydrophilic, low viscosity grade polymer\\u000a hydroxypropyl methylcellulose (HPMC K3LV). The co-solvent evaporation method

Priyanka Pandya; Surendra Gattani; Pankaj Jain; Lokesh Khirwal; Sanjay Surana

2008-01-01

376

Interaction between the effects of evaporation rate and amount of simulated rainfall on development of the free-living stages of Haemonchus contortus  

Microsoft Academic Search

A factorial experiment (3×4×2×3) was conducted in programmable incubators to investigate interaction between the effects of rainfall amount, rainfall distribution and evaporation rate on development of Haemonchus contortus to L3. Sheep faeces containing H. contortus eggs were incubated on sterilised soil under variable temperatures typical of summer in the Northern Tablelands of NSW, Australia. Simulated rainfall was applied in 1

Lauren J. O’Connor; Lewis P. Kahn; Stephen W. Walkden-Brown

2008-01-01

377

Evaporation pathways and solubility of Fe-Ca-Mg-rich salts in acid sulfate waters. A model for Martian ancient surface waters  

NASA Astrophysics Data System (ADS)

It has been suggested that Martian iron rich sulfate and oxyhydroxide deposits were precipitated from meltwaters[1], thought to have been acidic. Alternatively, iron(III)-rich hydrated sulfates from oxidized sulfides observed in the outcrops may occur as a result of long-term reactions[4]. Recent analysis of Martian materials support that they come from hydrothermal activity[5], which is highly consistent with the observation of enriched in iron, magnesium, silicon and calcium materials[2]. Independently of the nature of the sulfate formation paths on Mars, characterizing the interaction of saline mineral assemblages and the aqueous solutions necessary for their formation is significance in assessing Mars' hydrological and mineralogical evolution history. In this work we have characterized a layered deposit(Fig. 1) formed from the evaporation of stream water from Rio Tinto, Spain, a relevant Mars analog site[6]. The minerals detected in-situ, confirmed later via high resolution laser Raman spectroscopy in the laboratory, are, from bottom to top: (A) mixture of goethite and probably schwermannite; (B) goethite; (C) mixture of gypsum and highly hydrated ferric sulfates; (D) hexahydrite; and (E) mixture of hexahydrite and epsomite. What we observed in this deposit is the precipitation of relatively insoluble hydroxysulfates (schwermannite admixed with goethite), followed by the precipitation of other relatively insoluble ferric and gypsum, and finally the occurrence of the very soluble Mg-sulfates. We are currently investigating the correlation of this evaporite deposit with the hydrochemistry of the stream water from which it evaporated through dedicated laboratory analysis of natural mineral and aqueous samples. A solubility model including the minerals identified in this work will be reported at the conference. The study of this particular acid sulfate system (with analog mineralogy to that observed in Meridiani[3]) provides constraints on the evaporation pathways that may lead to a better understanding of the composition of ancient surface waters on Mars from which certain complex mineral assemblages are thought to have been formed.

Sobron, P.; Sansano, A.; Sanz, A.

2011-12-01

378

Quantitative Microbiological Analysis of Bacterial Community Shifts in a High-Rate Anaerobic Bioreactor Treating Sulfite Evaporator Condensate  

PubMed Central

The bacterial population of a high-rate, anaerobic, fixed-bed loop reactor treating sulfite evaporator condensate from the pulp industry was studied over a 14-month period. This period was divided into seven cycles that included a startup at the beginning of each cycle. Some 82% of the total biomass was immobilized on and between the porous glass rings filling the reactor. The range of the total number of microorganisms in these biofilms was 2 × 109 to 7 × 109 cells per ml. Enumeration and characterization by microbiological methods and by phase-contrast, epifluorescence, and electron microscopy showed that the samples consisted mainly of the following methanogens: a Methanobacterium sp., a Methanosarcina sp., a Methanobrevibacter sp., and a Methanothrix sp., as well as furfural-degrading sulfate-reducing bacteria resembling Desulfovibrio furfuralis. Viable counts of hydrogenotrophic methanogens were relatively stable (mostly within the range of 3.2 × 108 to 7.5 × 108 cells per ml), but Methanobrevibacter cells increased from <5 to 30% of the total hydrogenotrophic count after transfer of the fixed bed into a second reactor vessel. Acetotrophic methanogens reached their highest numbers of 1.3 × 108 to 2.6 × 108 cells per ml in the last fermentation cycles. They showed a morphological shift from sarcinalike packets in early samples to single coccoid forms in later phases of the fermentation. Furfural-degrading sulfate reducers reached counts of 1 × 107 to 5.8 × 107 cells per ml. The distribution of the chief metabolic groups between free fluid and biofilms was analyzed in the fifth fermentation cycle: 4.5 times more furfural degraders were found in the free fluid than in the biofilms. In contrast, 5.8 times more acetotrophic and 16.6 times more hydrogenotrophic methanogens were found in the biofilms than in the free liquid. The data concerning time shifts of morphotypes among the trophic groups of methanogens corroborated the trends observed by using immunological assays on the same samples. Images

Ney, U.; Macario, A. J. L.; de Macario, E. Conway; Aivasidis, A.; Schoberth, S. M.; Sahm, H.

1990-01-01

379

Evaluation of the freeze-thaw/evaporation process for the treatment of produced waters. Quarterly technical progress report, October 1, 1995--December 31, 1995  

SciTech Connect

The use of freeze-crystallization is being increasingly acknowledged as a low-cost, energy-efficient method for purifying contaminated water. Freeze-crystallization has been shown to be effective in removing a wide variety of contaminants from water. Water purification by using natural conditions to promote freezing appears to be an extremely attractive process for the treatment of contaminated water in many areas where natural climatic conditions will seasonally promote freezing. The natural freezing process can be coupled with natural evaporative processes to treat oil and gas produced waters year-round in regions where sub-freezing temperatures seasonally occur. The objectives of this research are related to development of a commercially-economic natural freeze-thaw/evaporation (FTE) process for the treatment and purification of water produced in conjunction with oil and gas.

Boysen, J.; Morotti, J.

1996-01-01

380

Precipitate formation in a porous rock through evaporation of saline water  

NASA Astrophysics Data System (ADS)

We examine the motion of a high-pressure aqueous solution, through a low-permeability fracture, towards a low-pressure well. As the liquid decompresses in the fractures it expands, and for sufficiently high initial temperature the liquid reaches the boiling point. A vaporization front then develops, so that vapour issues from the well. As the fluid evaporates near the well, the salt concentration of the residual fluid increases. If the salt concentration increases beyond the saturation limit, then the evaporation leads to precipitation of salt in the fracture. We find a new family of self-similar solutions to describe the boiling and precipitation in a single idealized fracture, which at long times remains approximately isothermal owing to the cross-fracture heat transfer. The solutions describe the mass of salt that precipitates as a function of the initial salt concentration, the reservoir temperature and pressure, and the well pressure. In fact, this family of self-similar solutions is multi-valued: we identify a liquid-advection-dominated regime, in which the boiling front advances slowly and the fracture porosity decreases significantly, and a boiling-dominated regime, in which the boiling front advances more rapidly, and less precipitate forms at each point in the fracture. As the pressure difference between the well and the far field reservoir increases, these solutions converge, and eventually coincide. Beyond this critical point, there is no similarity solution, since the advective flux of salt from the far-field would produce more precipitate than can be taken up in the fracture adjacent to the boiling front. Instead, the rock will become fully sealed through precipitation, thereby suppressing flow into the well. We extend the model to show that an analogous result also occurs within an extensive porous layer. However in that case, the system is not isothermal; instead, the heat flux is supplied in the direction of flow, while the cross-flow heat flux is small. We discuss the relevance of the work to the natural venting of steam in high-temperature geothermal systems.

Tsypkin, George G.; Woods, Andrew W.

2005-08-01

381

Evaporating apparatus  

SciTech Connect

A heat recovery system is described comprising in combination forming a closed loop, an evaporator means for converting a working fluid into vapor with a waste heat, a steam engine means for driving a load with the vapor produced in the evaporator means, a condensor means for liquefying the vapor coming out of the steam engine means, and a pump means for circulating the working fluid in the closed loop, the improvement of the evaporator means comprising a high temperature side evaporator and a low temperature side evaporator connected in series in a flowing direction of a heat source, a first and second pipe line for directing fluid being evaporated therethrough, and an ejector having a suction inlet and a discharge outlet of drive steam and an induction port of steam being sucked, wherein the first pipe is linked through the high temperature side evaporator to the suction inlet of the ejector, and the second pipe line is branched from the first pipe line at the upstream side of the high temperature side evaporator, and linked through the low temperature side evaporator to the induction port of the ejector.

Sumitomo, H.

1988-06-28

382

Effects of Interfacial Forces on the Evaporation of a Superheated Water Droplet in Hot Immiscible Oil.  

National Technical Information Service (NTIS)

The release of vapor bubbles from the surface of a superheated water droplet submerged in a hot immiscible oil was studied. Theoretical calculations indicate that the maximum bubble size and the residence time of the vapor bubble at the oil/water interfac...

F. C. H. Jongenelen F. Groeneweg J. H. Gouda

1977-01-01

383

Scale Control in Sea Water Evaporators, Point Loma I, San Diego, California.  

National Technical Information Service (NTIS)

The nature and importance of deposits of foreign matter, known as 'scale', on heat transfer surfaces of distillation equipment used to make fresh water from sea water are described. Methods of preventing, controlling, and/or removing scale deposits are di...

S. F. Mulford

1964-01-01

384

Scale Control in Sea Water Evaporators. (Point Loma I, San Diego, California).  

National Technical Information Service (NTIS)

The nature and importance of deposits of foreign matter, known as 'scale,' on heat transfer surfaces of distillation equipment used to make fresh water from sea water are described. Methods of preventing, controlling, and/or removing scale deposits are di...

S. F. Mulford

1964-01-01

385

Differences in evaporation between a floating pan and class a pan on land  

USGS Publications Warehouse

Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 31, 2005, at a small natural wetland located in the alluvium of the Canadian River near Norman, Oklahoma, at the U.S. Geological Survey Norman Landfill Toxic Substances Hydrology Research Site. Floating pan evaporation rates were compared with evaporation rates from a nearby standard Class A evaporation pan on land. Floating pan evaporation rates were significantly less than land pan evaporation rates for the entire period and on a monthly basis. Results indicated that the use of a floating evaporation pan in a small free-water surface better simulates actual physical conditions on the water surface that control evaporation. Floating pan to land pan ratios were 0.82 for March, 0.87 for April, 0.85 for May, 0.85 for June, 0.79 for July, and 0.69 for August. ?? 2008 American Water Resources Association.

Masoner, J. R.; Stannard, D. I.; Christenson, S. C.

2008-01-01

386

Development of New Chemical Additives and Treatments for Scale Control in Saline Water Evaporators.  

National Technical Information Service (NTIS)

Using laboratory procedures which simulated distillation conditions (including the presence of a heat-exchange surface), it was demonstrated that aminophosphonic acid additives in equivalent concentrations of 2-4.5 ppm in input sea water inhibited both al...

J. F. Miller J. L. Means A. E. Austin J. A. Eibling

1982-01-01

387

Evaporation estimates from the Dead Sea and their implications on its water balance  

Microsoft Academic Search

The Dead Sea (DS) is a terminal hypersaline water body situated in the deepest part of the Jordan Valley. There is a growing\\u000a interest in linking the DS to the open seas due to severe water shortages in the area and the serious geological and environmental\\u000a hazards to its vicinity caused by the rapid level drop of the DS. A

Ibrahim M. Oroud

388

Hot air drum evaporator  

DOEpatents

An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

Black, Roger L. (Idaho Falls, ID)

1981-01-01

389

Effects of discharging acid-mine drainage into evaporation ponds lined with clay on chemical quality of the surrounding soil and water  

Microsoft Academic Search

Compacted clay layers are commonly used as liners to limit acid-mine drainage (AMD) percolation into the surrounding environment from containment areas or ponds. In the long term, this practical and sometimes economical means of AMD disposal has often presented other considerable environmental challenges. The chemical quality of soil, river water and groundwater surrounding evaporation ponds lined with clay was determined

F. Mapanda; G. Nyamadzawo; J. Nyamangara; M. Wuta

2007-01-01

390

THE USE OF DI WATER TO MITIGATE DUSTING FOR ADDITION OF DWPF FRIT TO THE SLURRY MIX EVAPORATOR  

SciTech Connect

The Defense Waste Processing Facility (DPWF) presently is in the process to determine means to reduce water utilization in the Slurry Mix Evaporator (SME) process, thus reducing effluent and processing times. The frit slurry addition system mixes the dry frit with water, yielding approximately a 50 weight percent slurry containing frit and the other fraction water. This slurry is discharged into the SME and excess water is removed via boiling. To reduce this water load to the SME, DWPF has proposed using a pneumatic system in conveying the frit to the SME, in essence a dry delivery system. The problem associated with utilizing a dry delivery system with the existing frit is the generation of dust when discharged into the SME. The use of water has been shown to be effective in the mining industry as well in the DOE complex to mitigate dusting. The method employed by SRNL to determine the quantity of water to mitigate dusting in dry powders was effective, between a lab and bench scale tests. In those tests, it was shown that as high as five weight percent (wt%) of water addition was required to mitigate dust from batches of glass forming minerals used by the Waste Treatment Plant at Hanford, Washington. The same method used to determine the quantity of water to mitigate dusting was used in this task to determine the quantity of water to mitigate this dusting using as-received frit. The ability for water to mitigate dusting is due to its adhesive properties as shown in Figure 1-1. Wetting the frit particles allows for the smaller frit particles (including dust) to adhere to the larger frit particles or to agglomerate into large particles. Fluids other than water can also be used, but their adhesive properties are different than water and the quantity required to mitigate dusting is different, as was observed in reference 1. Excessive water, a few weight percentages greater than that required to mitigate dusting can cause the resulting material not to flow. The primary objective of this task is to perform bench scale testing on various frits that have been used at DWPF or in test programs at SRNL to determine the quantity of de-ionized (DI) water required to mitigate dusting per mass basis of frit. The quantity of DI water required was determined visually by observing the effluent port of the mixer, and DI water addition was made to the point where no visible dust was observed leaving the effluent port. A total of eight different frits were selected for testing. Secondary objectives in this task include the following: (1) Video taping of the de-dusting procedure, (2) Particle size distribution analyses of the dry and wetted frits at the weight fraction of water required for de-dusting, (3) Plate flow tests to determine angle of flow and quantity of material remaining on plate at 90 degrees, (4) Microscopy of dry and wetted frit, and (5) Effect of excess water for selected frits on plate flow. The above analyses were performed within one hour of water addition, to minimize the effect of evaporative water losses. To better understand the size of dust particles, perform settling tests on selected frits and capture the fines. Analyze the fines for particle size distribution. Finally, it is expected that the surface area of frit is an important parameter in the quantity of water required for dust mitigation. An analysis of particle size distribution (PSD) data of as-received frit analyzed by SRNL over the past two to three years will be performed to determine the variation in the distribution of as-received frit. The following objectives were stated in the Technical Task Request4 as objectives that given adequate time would provide insight in helping DWPF in assessing equipment or processes for de-dusting and processing of dry frit. Due to time constraints, commercial methods for dedusting are provided. These results are detailed in section 3.7. Obtain design information from Hanford with respective to equipment used for dedusting. Suggestions on enhanced design features, such as flush water, pipe air purges, humidified compresse

Hansen, E.

2010-07-21

391

Evaporation-induced cavitation in nanofluidic channels  

PubMed Central

Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitation in the nanoscale is generally believed to be energetically unfavorable and has never been experimentally demonstrated. Here we report evaporation-induced cavitation in water-filled hydrophilic nanochannels under enormous negative pressures up to -7 MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro- and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale.

Duan, Chuanhua; Karnik, Rohit; Lu, Ming-Chang; Majumdar, Arun

2012-01-01

392

Measured soil water evaporation as a function of the square root of time and reference ET  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sunflower (Helianthus annuus L.) is a drought-adapted crop with a short growing season that reduces irrigation requirements and makes it ideal for regions with limited irrigation water supplies. Our objectives were a) to evaluate the yield potential of sunflower under deficit irrigation and b) det...

393

Northwest Australian Shelf Dynamics Experiment: Evaporative Dense Water Formation over the Inner-Shelf  

NASA Astrophysics Data System (ADS)

During the June-July 2003 Northwest Australian Shelf Dynamics Experiment, several high-resolution along- and cross-shelf sections of temperature, salinity, and currents were collected over the inner-shelf (20-50 m water depth), using a towed undulating instrument platform (MiniBat) and shipboard acoustic Doppler current profiler (ADCP). Additional ship-based sensors observed air temperature, sea surface temperature, relative humidity, precipitation, downward long and short wave radiation, and wind speed and direction - from these observations surface heat and freshwater fluxes were estimated. The inner-shelf is characterized by increasingly cool, salty and dense waters onshore, and a strong front is present near the 25 m isobath. Vertically, inner-shelf waters are characterized by a dramatic two-layer system; a well-mixed surface layer that shares characteristics with the offshore surface mixed layer and a cool, salty bottom layer that extends from the inner-shelf front, across the shelf, and detaches along the main thermocline at the shelf break. Analysis of the ship-based meteorological measurements reveal a large latent heat flux out of the ocean that overwhelms insolation and maintains the well-mixed surface layer and the cross-shelf structure (increasingly cool, salty and dense water onshore).

Shearman, R.; Brink, K. H.; Bahr, F.

2004-12-01

394

Evaporative Cooling by Mist and Sprinkle Irrigation and Conserving Water in Vegetable Irrigation in Arizona.  

National Technical Information Service (NTIS)

Temperature, yield response and water-use efficiency are given for eight cultivars of peppers, two of tomatoes and one of potatoes irrigated by dead-level furrow, regular and intermittent rotating sprinkling and micromist with bare soil, with black plasti...

A. J. Pratt F. C. Harper

1983-01-01

395

Horizontal convection in water heated by infrared radiation and cooled by evaporation: scaling analysis and experimental results  

NASA Astrophysics Data System (ADS)

An experimental study of horizontal convection with a free surface has been conducted. Fresh water was heated from above by an infrared lamp placed at one end of a tank, and cooled by evaporation as the water moved away from the heat source. The heat radiated from the lamp was absorbed in a thin (less than 1 mm) layer next to the surface, and then advected and diffused away from the lamp region. Latent heat loss dominated the surface cooling processes and accounted for at least 80% of the energy loss. The velocity and temperature fields were recorded with PIV technology, thermometers and an infrared camera. In similarity with previous horizontal convection experiments the measurements showed a closed circulation with a gradually cooling surface current moving away from the lamp. Below the surface current the water was stably stratified with a comparatively thick and slow return current. The thickness and speed, and hence the mass transport, of the surface- and the return current increased with distance from the lamp. The latent cooling at the free surface gives a heat flux which increases with the temperature difference between the surface water and the air above it. Hence the surface temperature relaxes towards an equilibrium value, for which the heat flux is zero. The main new result is a scaling law, taking into account this relaxation boundary condition for the surface temperature. The new scaling includes a (relaxation) length scale for the surface temperature, equivalent to the distance the surface current travels before it has lost the heat that was gained underneath the lamp. The length scale increases with the forcing strength and the (molecular) thermal diffusivity but decreases with the strength of the relaxation. Numerical simulations of this problem for a shallow tank have also been performed. The velocity and temperature in the laboratory and numerical experiments agree with the scaling laws in the upper part of the tank, but not in the lower.

Wåhlin, A. K.; Johansson, A. M.; Aas, E.; Broström, G.; Weber, J. E. H.; Grue, J.

2010-03-01

396

Evaluation of a two-stage evaporation approximation for contrasting vegetation cover  

Microsoft Academic Search

For a regional assessment of water needs and consumption in semiarid agricultural zones, one needs robust and simple tools that provide space-time estimates of evaporation losses. Most operational evaporation estimates rely on semiempirical relationships that are not generally applicable. Several authors have proposed physically based simple expressions to model the “energy-limited” (stage-one) and the “supply-limited” (stage-two) evaporation rates during a

G. Boulet; A. Chehbouni; I. Braud; B. Duchemin; A. Lakhal

2004-01-01

397

Improvement in the determination of 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be by gamma spectrometry on evaporated fresh water samples.  

PubMed

For the U-Th series radionuclides investigation in natural freshwater, a simple, fast, and not laboratory intensive method which consists of evaporating the water samples to dryness in the presence of carriers is presented. The small volume of the residue (1-2 cm3) leads to a good efficiency for gamma counting and limits the self-absorption effect for the low energy gamma rays (less than 200 keV). The best efficiency is obtained with a well-type Ge detector. To determine the evaporation yields a river with a common uranium content, the Seine river (France), was selected. By using internal spikes and more conventional techniques of investigation, we demonstrate that the evaporation is quantitative for U, Th, Ra, Pb, and Be. The residue of a 3 L, standard superficial freshwater, evaporated sample was analyzed in a high efficiency, low background Ge detector, which leads to a sufficient precision for most environmental studies. The method has been applied to rain, river, and lake waters to study the impact of disused uranium mine water inputs on the 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be river and lake contents in the U mining area of Limoges (France). PMID:14620828

Cazala, C; Reyss, J L; Decossas, J L; Royer, A

2003-11-01

398

An analysis on the rates and regulation of insensible water loss through the eccrine sweat glands.  

PubMed

An analysis is presented on insensible water loss from the human body at rest through exposed skin surfaces into still air. Possible sites of moisture release are identified as the stratum corneum of the skin, free surfaces of dilute sweat liquids perpetually present in the microscopic ducts of a large population of eccrine sweat glands, and moist microvillous processes which line part of the periductal surfaces in the glands, particularly in the helical coils within the stratum spinosum of the epidermis. Water supply to the sites involves transepidermal migration across skin tissue layers, secretion and partial reabsorption of solutes and water within eccrine glands, and transport across periductal lining of eccrine glands from the surrounding connective tissues respectively. Evaporation and gas phase diffusion within eccrine ducts were modelled. Basal loss rates of water (as regulated by the ambient temperature and relative humidity and by aspects of the anatomy of and physiological factors for eccrine glands, the epidermis and the dermis) were calculated at between 1 and 20 g hr-1 at an ambient temperature of 25 degrees C and a relative humidity of 60% as an example. Such rates are significant fractions of experimental values for insensible water loss rates reported at between 4 and 35 g hr-1 in air at 22-30 degrees C and a relative humidity of 30-60%. PMID:2630794

Jeje, A; Koon, D

1989-12-01

399

Enhancement of spray flash evaporation by means of the injection of bubble nuclei  

SciTech Connect

Spray flash evaporators are being used or considered for power systems utilizing solar energy, ocean thermal energy, and geothermal energy. As part of an attempt to develop a compact, efficient flash evaporator, an experimental study of the effect of injection of bubble nuclei has been conducted. The bubble nuclei were generated by electrolyzing warm water, which was ejected from a simple tubular nozzle into a low-pressure vapor zone. Effects of electrolytic current level, nozzle diameter, liquid flow rate, liquid temperature, and superheat were investigated. The evaporator rates attained were superior to those in conventional multistage flash evaporators with open channels.

Miyatake, O.; Ide, Y.; Tomimura, T.

1985-05-01

400

EHD-Enhanced Water Evaporation from Partially Wetted Glass Beads with Auxiliary Heating from Below  

Microsoft Academic Search

Earlier studies have shown that an electric field in the form of corona wind can significantly enhance drying rate. It is particularly effective in the early stage of drying when the material is fully wetted. However, the effectiveness of corona wind in drying a partially wetted material, which is commonly believed decreasing, has not been critically examined. For the present

F. C. Lai; C. C. Wang

2009-01-01

401

Morphology tunable pinning force and evaporation modes of water droplets on PDMS spherical cap micron-arrays  

Microsoft Academic Search

It is well known that three modes (the constant contact radius mode, the constant contact angle mode and the mixed mode) are existed during the droplet evaporation process. However, the mechanisms of these modes and their transitions are still in dispute. In this paper, pinning force is introduced and formulated to give a quantitative explanation to the evaporation modes and

Chi Zhang; Xiaolong Zhu; Luwei Zhou

2011-01-01

402

Metallization: Evaporation  

NSDL National Science Digital Library

This website includes an animation depicting an overview of the metallization evaporation processes. Objective: Identify the process of evaporation. This simulation is from Module 061 of the Process & Equipment II Cluster of the MATEC Module Library (MML). You can find this animation under the section "Process & Equipment II." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtml

2012-10-05

403

Isotopic Exchange Rate Constant between Snow and Liquid Water  

Microsoft Academic Search

Isotopic exchange rate between liquid water and ice is crucial in determining the isotopic evolution of a snowpack and its melt. The rate constant for oxygen isotopic exchange has been reported by Taylor et al. [2002] using three column melting experiments with different heights and melt rates. In this work, we obtained the hydrogen isotopic exchange rate constant using samples

J. Lee; X. Feng; E. S. Posmenrier; A. M. Faiia

2007-01-01

404

An Analysis of Residential Water Demand and Water Rates in Minnesota.  

National Technical Information Service (NTIS)

Price elasticity of demand for residential water in Minnesota is examined, along with policy implications. Common rate forms for pricing municipal water are described and analyzed. Recommendations for improving rate structures in Minnesota are made in rel...

R. L. Gardner

1977-01-01

405

EFFECTS OF ADDITION RATE AND ACID MATRIX ON THE DESTRUCTION OF AMMONIUM BY THE SEMI-CONTINUOUS ADDITION OF SODIUM NITRITE DURING EVAPORATION  

SciTech Connect

The destruction of ammonium by the semi-continuous addition of sodium nitrite during acidic evaporation can be achieved with a wide range of waste compositions. The efficiency of nitrite utilization for ammonium destruction was observed to vary from less than 20% to 60% depending on operating conditions. The effects of nitric acid concentration and nitrite addition rate are dominant factors that affect the efficiency of nitrite utilization for ammonium destruction. Reducing the acid concentration by performing acid recovery via steam stripping prior to performing nitrite destruction of ammonium will require more nitrite due to the low destruction efficiency. The scale-up of the baseline rate nitrite addition rate from the 100 mL to the 1600 gallon batch size has significant uncertainty and poses the risk of lower efficiency at the plant scale. Experience with plant scale processing will improve confidence in the application of nitrite destruction of ammonium to different waste streams.

Kyser, E

2007-08-27

406

Determination of Domestic Water Consumption Rates under Varying Water Pressures.  

National Technical Information Service (NTIS)

An experimental study of water consumption in Mayaguez, Puerto Rico determined that pressure is not related to domestic consumption. The cause of variations in the city's domestic consumption was not determined. Data used in the study are tabulated. A bri...

L. A. Nunez M. F. de Vera J. M. Fidalgo

1969-01-01

407

Evaporation from groundwater discharge playas, Estancia Basin, central New Mexico  

USGS Publications Warehouse

Bowen ratio meteorological stations have been deployed to measure rates of evaporation from groundwater discharge playas and from an adjacent vegetated bench in the Estancia Basin, in central New Mexico. The playas are remnants of late Pleistocene pluvial Lake Estancia and are discharge areas for groundwater originating as precipitation in the adjacent Manzano Mts. They also accumulate water during local precipitation events. Evaporation is calculated from measured values of net radiation, soil heat flux, atmospheric temperature, and relative humidity. Evaporation rates are strongly dependent on the presence or absence of standing water in the playas, with rates increasing more than 600% after individual rainstorms. Evaporation at site E-12, in the southeastern part of the playa Complex, measured 74 cm over a yearlong period from mid-1997 through mid-1998. This value compares favorably to earlier estimates from northern Estancia playas, but is nearly three times greater than evaporation at a similar playa in western Utah. Differences in geographical position, salt crust composition, and physical properties may explain some of the difference in evaporation rates in these two geographic regions. (C) 2000 Elsevier Science B.V.

Menking, K. M.; Anderson, R. Y.; Brunsell, N. A.; Allen, B. D.; Ellwein, A. L.; Loveland, T. A.; Hostetler, S. W.

2000-01-01

408

Improved Evaporation Measurements from Lake Tahoe, California  

Microsoft Academic Search

Accurate measurements of evaporation are important to management of water storage as well as to understanding turnover and nutrient storage in lakes. Evaporation has been a poorly constrained component of past water budget studies of Lake Tahoe, California and is the last major unknown for effective management of the Truckee River basin under the Truckee River Operating Agreement (TROA). Evaporation

G. L. Dana; J. C. Trask

2001-01-01

409

State-of-the-ART Evaporation Technology: Topical Report.  

National Technical Information Service (NTIS)

This report discusses evaporation theory, measurement and estimation as well as the effects of water quality on evaporation. Emissions from waste effluents is also mentioned. The theory and equations to represent evaporation using energy balances, mass tr...

V. R. Hasfurther M. J. Haass

1986-01-01

410

Thermal tolerance and evaporative water loss of the mangrove prosobranch Tympanotonus fuscatus var. radula L. (Cerithiacea: Potamididae).  

PubMed

Rate of weight loss and mortality, of the Nigerian periwinkle, Tympanotonus fuscatus var. radula L. were investigated during prolonged exposure to air for one month. Short term thermal tolerance in the laboratory was carried out by heating the water in which the animals are placed at the rate of 1 degree C every 10 min. The group exposed to air continued to lose weight; when the experiment was terminated after 4 weeks, 20% of body weight was lost and 5 out of 40 periwinkles died, while the control experimental snails lost 11% of body weight, due to starvation. The species has an upper lethal temperature of 46-48.5 degrees C, much higher than the temperature of its habitat. Survival of T. fuscatus var. radula out of water and adaptation to high temperature suggests the presence of highly adaptive mechanisms of water balance and metabolism. PMID:19070007

Egonmwan, Rosemary I

2007-01-01

411

Evaporation of pure liquid sessile and spherical suspended drops: a review.  

PubMed

A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by a contact line and characterized by contact angle, contact radius and drop height. Diffusion-controlled evaporation of a sessile drop in an ambient gas is an important topic of interest because it plays a crucial role in many scientific applications such as controlling the deposition of particles on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, drop wise cooling, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials in the last decades. This paper presents a review of the published articles for a period of approximately 120 years related to the evaporation of both sessile drops and nearly spherical droplets suspended from thin fibers. After presenting a brief history of the subject, we discuss the basic theory comprising evaporation of micrometer and millimeter sized spherical drops, self cooling on the drop surface and evaporation rate of sessile drops on solids. The effects of drop cooling, resultant lateral evaporative flux and Marangoni flows on evaporation rate are also discussed. This review also has some special topics such as drop evaporation on superhydrophobic surfaces, determination of the receding contact angle from drop evaporation, substrate thermal conductivity effect on drop evaporation and the rate evaporation of water in liquid marbles. PMID:22277832

Erbil, H Yildirim

2012-01-08

412

On the theory relating changes in area-average and pan evaporation (Invited)  

NASA Astrophysics Data System (ADS)

Theory relating changes in area-average evaporation with changes in the evaporation from pans or open water is developed. Such changes can arise by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation that modify surface evaporation rates in the same direction, and Type (b) processes related to coupling between the surface and atmospheric boundary layer (ABL) at the landscape scale that usually modify area-average evaporation and pan evaporation in different directions. The interrelationship between evaporation rates in response to Type (a) changes is derived. They have the same sign and broadly similar magnitude but the change in area-average evaporation is modified by surface resistance. As an alternative to assuming the complementary evaporation hypothesis, the results of previous modeling studies that investigated surface-atmosphere coupling are parameterized and used to develop a theoretical description of Type (b) coupling via vapor pressure deficit (VPD) in the ABL. The interrelationship between appropriately normalized pan and area-average evaporation rates is shown to vary with temperature and wind speed but, on average, the Type (b) changes are approximately equal and opposite. Long-term Australian pan evaporation data are analyzed to demonstrate the simultaneous presence of Type (a) and (b) processes, and observations from three field sites in southwestern USA show support for the theory describing Type (b) coupling via VPD. England's victory over Australia in 2009 Ashes cricket test match series will not be mentioned.

Shuttleworth, W.; Serrat-Capdevila, A.; Roderick, M. L.; Scott, R.

2009-12-01

413

Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water  

NASA Astrophysics Data System (ADS)

We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

2012-03-01

414

Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water  

NASA Astrophysics Data System (ADS)

We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol particles, we illustrate how the formation and evaporation of volatile reaction products like nonanal can cause a decrease in the size of oleic acid particles exposed to ozone.

Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

2011-12-01

415

COMPARISON OF METHODS USED TO ESTIMATE LAKE EVAPORATION FOR A WATER BUDGET OF LAKE SEMINOLE, SOUTHWESTERN GEORGIA AND NORTHWESTERN FLORIDA  

Microsoft Academic Search

Four empirical methods for calculating evaporation were compared with calculations of evapo- ration using the energy budget for Lake Seminole, south- western Georgia and northwestern Florida, for April 2000-September 2001. Methods compared were the Priestly-Taylor, Penman, DeBruin-Keijman, and Papa- dakis equations. Evaporation calculated using the energy budget and empirical methods then were compared with estimates published daily by the Georgia

Melinda S. Mosner; Brent T. Aulenbach

2003-01-01

416

Thermal tolerance, evaporative water loss, air-water oxygen consumption and zonation of intertidal prosobranchs: a new synthesis  

Microsoft Academic Search

Duration of emergence increases with tidal height on rocky shores therefore, emergence adaptations in intertidal species such as littorine and other prosobranch gastropods have been considered correlated with zonation patterns; temperature tolerance, desiccation resistance and aerial respiration rate all commonly assumed to increase progressively with increasing zonation level. Such direct correlations are rarely observed in nature. Maximal aerial gas exchange

Robert F. McMahon

1990-01-01

417

Impact of the Air Flow Pattern and the Thermal Load in a Room on the Heat and Mass Transfer Coefficient across a Person, especially on the Evaporation of Water from the Eyes  

Microsoft Academic Search

The evaporation of water from a small humidified area at head level of a heated dummy is measured. The aim is to find out the influence of the relative humidity and the local mass transfer coefficient on the local evaporation with respect to the behaviour of the tear film in eyes. It is obvious that not only the relative humidity,

KLAUS FITZNER; INGO GORES

418

Evaporation loss of dissolved volatile substances from ice surfaces.  

PubMed

Volatile acidic solutes were used to make dilute solutions, which were frozen by various methods. The concentration of solutes and the pH of the samples were measured before and after being frozen. When the sample solution is frozen from the bottom to the top, solutes are concentrated into the unfrozen solution (i.e., the upper part of the sample) due to the freeze concentration effect. Thereafter, concentrated anions combine with protons to form acids, and the amount of acids in the unfrozen solution increase as the ice formation progresses. At the end of freezing, the acid is saturated at the ice surface, and if the formed acid is volatile, then evaporation occurs. Frozen solutions were allowed to stand below 0 degrees C, where evaporation rates were obtained in the following order: formate > acetate > propionate > n-butyrate > chloride > nitrate. Except for nitrate, evaporation rates were enough to take place in frozen water of the natural environment (e.g., ice crystal, graupel, snow crystal, and frozen droplets). The relationship between the evaporation rate of volatile acids and their physical properties demonstrate that the evaporation rates of weak acids are faster than those of strong acids, and the evaporation rates among weak acids are the same as the volatility of weak acids. PMID:18661928

Sato, Keiichi; Takenaka, Norimichi; Bandow, Hiroshi; Maeda, Yasuaki

2008-07-29

419

Evaporation from Lake Mead, Arizona and Nevada, 1997-99  

USGS Publications Warehouse

Lake Mead is one of a series of large Colorado River reservoirs operated and maintained by the Bureau of Reclamation. The Colorado River system of reservoirs and diversions is an important source of water for millions of people in seven Western States and Mexico. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, conducted a study from 1997 to 1999 to estimate evaporation from Lake Mead. For this study, micrometeorological and hydrologic data were collected continually from instrumented platforms deployed at four locations on the lake, open-water areas of Boulder Basin, Virgin Basin, and Overton Arm and a protected cove in Boulder Basin. Data collected at the platforms were used to estimate Lake Mead evaporation by solving an energy-budget equation. The average annual evaporation rate at open-water stations from January 1998 to December 1999 was 7.5 feet. Because the spatial variation of monthly and annual evaporation rates was minimal for the open-water stations, a single open-water station in Boulder Basin would provide data that are adequate to estimate evaporation from Lake Mead.

Westenburg, Craig L.; DeMeo, Guy A.; Tanko, Daron J.

2006-01-01

420

COMPARING CONSTANT-RATE AND DECLINING-RATE DIRECT FILTRATION OF A SURFACE WATER  

EPA Science Inventory

Pilot-scale constant-rate and declining-rate direct filtration systems were evaluated for treating a high quality surface water, using two flow rates and alum or cationic polymer as the primary coagulant. Turbidity, particle count, and total coliform count were used to compare fi...

421

Corrosion Rates of Grinding Media in Mill Water.  

National Technical Information Service (NTIS)

This report presents data collected during research by the Bureau of Mines on corrosion of grinding media. Corrosion rates of eight alloys commonly used in grinding media were tested in synthetic mill water using an ultrasonic grinding device especially d...

W. K. Tolley I. L. Nichols J. L. Huiatt

1984-01-01

422

Rates, Constants, and Kinetics Formulations in Surface Water Quality Modeling.  

National Technical Information Service (NTIS)

Recent studies are reviewed to provide a comprehensive volume on state-of-the-art formulations used in surface water quality modeling along with accepted values for rate constants and coefficients. Topics covered include system geometric representation (s...

C. W. Chen D. Deimer S. W. Zison W. B. Mills

1978-01-01

423

Viscosity of Water at Low Rates of Shear  

Microsoft Academic Search

This Paper describes the determination of the coefficient of viscosity of water by a method in which water is forced along glass capillary tubes of about 1.5 to 2.0 mm. bore at rates of flow varying from 1 litre in two years to 1 litre in 24 years. The liquid fills a closed tubular circuit which for purposes of description

Albert Griffiths; Constance H. Griffiths

1920-01-01

424

Evaporation from a small prairie wetland in the Cottonwood Lake Area, North Dakota - An energy-budget study  

USGS Publications Warehouse

Evaporation from Wetland Pl in the Cottonwood Lake area of North Dakota, USA was determined by the energy-budget method for 1982-85 and 1987. Evaporation rates were as high as 0.672 cm day-1. Incoming solar radiation, incoming atmospheric radiation, and long-wave radiation emitted from the water body are the largest energy fluxes to and from the wetland. Because of the small heat storage of the water body, evaporation rates closely track solar radiation on short time scales. The effect of advected energy related to precipitation is small because the water quickly heats up by solar radiation following precipitation. Advected energy related to ground water is minimal because ground-water fluxes are small and groundwater temperature is only about 7 ??C. Energy flux related to sediment heating and thermal storage in the sediments, which might be expected to be large because the water is clear and shallow, affects evaporation rates by less than 5 percent.

Parkhurst, R. S.; Winter, T. C.; Rosenberry, D. O.; Sturrock, A. M.

1998-01-01

425

Spin coating with slow evaporation  

Microsoft Academic Search

The spin coating of polymer solutions is discussed, with emphasis on the nature of the evaporation boundary condition. A dimensional analysis reveals that the appropriate condition is a constant small evaporation rate, which is determined by the mass transfer in the adjacent atmosphere. An error in previous work [Phys. Fluids 31, 2786 (1988)] is brought to light, and it is

C. J. Lawrence

1990-01-01

426

A femtogram resolution mass sensor platform based on SOI electrostatically driven resonant cantilever. Part II: sensor calibration and glycerine evaporation rate measurement.  

PubMed

This paper presents mass measurements of glycerine beads performed by means of laterally resonant micro-cantilevers. The transducer architecture is based on a resonant cantilever electrostatically coupled by two parallel placed electrodes. Previous to glycerine measurements, a calibration of the mass sensor has been performed by measuring a standard mass based on latex spheres. From these measurements, a value of the mass responsivity is deduced. In addition, a study of the transducer phase noise has been carried out in order to determine the minimum detectable mass. Mass measurements experiments have been performed by detecting the change on the resonance frequency of the on-plane cantilever resonant mode, produced by locally deposited mass. Additionally, the mass losses detected on the calibrated transducer after glycerine drop deposition allowed determining its evaporation rate. PMID:16677762

Teva, J; Abadal, G; Torres, F; Verd, J; Pérez-Murano, F; Barniol, N

2006-04-18

427

Theoretical and testing performance of an innovative indirect evaporative chiller  

SciTech Connect

An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller successfully satisfy the indoor air conditioning load for the demo building. The indirect evaporative chiller has a potentially wide application in dry regions, especially for large scale commercial buildings. Finally, this paper presented the geographic regions suitable for the technology worldwide. (author)

Jiang, Yi; Xie, Xiaoyun [Department of Building Science and Technology, Tsinghua University, Beijing (China)

2010-12-15

428

WATER REQUIREMENTS AND SUPPLY FLOW RATES FOR BROILER PRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Surveys conducted recently revealed that a wide variety of nipple flow rates are being routinely used in broiler houses throughout the southern broiler producing states. A study was conducted to determine if the variety of nipple water flow rates found in industry has any effect on broiler performan...

429

Detecting inhomogeneities in pan evaporation time series  

Microsoft Academic Search

There is increasingly growing demand for evaporation data for studies of surface water and energy fluxes, especially for studies which address the impacts of global warming. To serve this purpose, a homogeneous evaporation data are necessary. This paper describes the use of two tests for detecting and adjusting discontinuities in Class A pan evaporation time series for 28 stations across

D. G. C. Kirono

2009-01-01

430

Effects of water flow rate, salt concentration and water temperature on efficiency of an electrolyzed oxidizing water generator  

Microsoft Academic Search

A three-factor central composite design was adopted to investigate the effects of water flow rate, water temperature and salt concentration on electrolysis efficiency and separation efficiency of an electrolyzed oxidizing water generator. Results indicated that electric potential (7.9–15.7 V) and power consumption (16–120 W) of the electrolysis cell were not affected by water flow rate, water temperature or salt concentration

S. Y. Hsu

2003-01-01

431

Evaporation and the mass and energy balances of the Dead Sea (Invited)  

NASA Astrophysics Data System (ADS)

The Dead Sea is a hypersaline terminal lake experiencing a water level drop of about 1 m/yr over the last decade. The existing estimations for the water balance of the lake are widely variable, reflecting the unknown subsurface water inflow, the rate of evaporation, and the rate of salt accumulation at the lake bottom. To estimate these we calculate the energy and mass balances for the Dead Sea utilizing measured meteorological and hydrographical data from 1996 to 2009. The data is measured from a buoy located in the Dead Sea 5, km from the nearest shore. The data includes solar radiation (incoming), long wave radiation (downward and upward looking), wind velocity, relative humidity, air temperature, air pressure and water temperature profile. Using energy balance we calculate the evaporation rate, taking into account the impact of lowered surface water activity. From mass balance considerations we calculate the salt precipitation rate, which was about 0.1 m/yr during this period. Using an overall mass balance we get the relation between water inflows, which are the least constrained quantity, and the evaporation rate. The average annual inflow is 265-325 mcm/yr, corresponding to an evaporation rate of 1.1-1.2 m/yr. Higher inflows, suggested in previous studies, call for increased evaporation rate and are therefore not in line with the energy balance. We also take into account the spatial variations and discuss how well the data measured in the buoy represent the Dead Sea surface conditions.

Lensky, N.; Gavrieli, I.; Gertman, I.; Nehorai, R.; Lensky, I. M.; Lyakhovsky, V.; Dvorkin, Y.

2009-12-01

432

Analysis of the e-beam evaporation of titanium and Ti-6Al-4V  

SciTech Connect

An experimental and finite element analysis was performed for the electron-beam evaporation of Ti and Ti-6Al-4V from a bottom-feed system. The bulk evaporation rate was measured by feed consumption, and the pool elevation was held constant by adjusting the feed rate in a closed-loop control system. The instantaneous titanium and aluminum evaporation rates were determined by laser absorption in the vapor plume. Water temperature rises in cooling water circuits provided heat flows, and post-run cross sections revealed the location of the solidification zone. The MELT finite element code was applied to model the steady-state two-dimensional fluid flow and energy transport in the rod. There was good agreement between model and measured values of the heat flows and solidification boundaries for Ti. Measured bulk evaporation rates were similar for Ti and Ti-6-4 with greater variation observed for the Ti values. The model evaporation rates were higher than the measured values, but a similar linear dependence on e-beam power was observed in all cases. In a Ti-6-4 evaporation experiment with steady process conditions, laser absorption measurements showed much larger fluctuations in the evaporation rate for Al than Ti.

Westerberg, K.W.; Merier, T.C.; McClelland, M.A.; Braun, D.G.; Berzins, L.V.; Anklam, T.M.; Storer, J.

1998-02-11

433

Thermal Loading of Hyco Lake, North Carolina. The Effect of Heated Water on Temperature and Evaporation, 1966-74.  

National Technical Information Service (NTIS)

Between May 1966 and December 1974, four phases of thermal loading from three steam-electric generators have resulted in higher temperatures and increased evaporation from Hyco Lake, a 4,350 acre (1,760 hectares) reservoir in north-central North Carolina....

G. L. Giese

1976-01-01

434

The Preparation and Characterization of Poly(lactide-co-glycolide) Microparticles. II. The Entrapment of a Model Protein Using a (Water-in-Oil)inWater Emulsion Solvent Evaporation Technique  

Microsoft Academic Search

Poly(lactide-co-glycolide) (PLG) microparticles with entrapped antigens have recently been investigated as controlled-release vaccines. This paper describes the preparation of PLG microparticles with an entrapped model antigen, ovalbumin (OVA), using a (water-in-oil)-in-water emulsion solvent evaporation technique. In a series of experiments, the effects of process parameters on particle size and OVA entrapment were investigated. It was found that smooth, spherical microparticles

Hayley Jeffery; Stanley S. Davis; Derek T. O'Hagan

1993-01-01

435

Substate and evaporation rate dependent orientation and crystalline organization of sexithiophene films vacuum deposited onto Au and HOPG  

NASA Astrophysics Data System (ADS)

The orientation and the crystalline organization of the films depend largely on the nature of the substrate and the deposition rate. The substrate effect is related to its interactions with the oligomers and also to the molecular mobility at the surface. It depends also largely on the deposition rate. L'orientation et l'organisation structurale des films de sexithiophène évaporés sous vide sont fortement liées à la nature du substrat (Au, HOPG) et à la vitesse de dépôt. L'effet du substrat est lié aux interactions avec les oligomères ainsi qu'à la mobilité de ces derniers sur la surface. Cet effet dépend largement de la vitesse d'évaporation.

El Ardhaoui, M.; Lang, P.; Garnier, F.; Roger, J. P.

1998-06-01

436

Molecular Distillation of Palm Oil Distillates: Evaporation Rates, Relative Volatility, and Distribution Coefficients of Tocotrienols and other Minor Components  

Microsoft Academic Search

The effects of feed flow rate and temperature of distillation on extraction of minor components from PFAD were studied in terms of concentration, distribution coefficient and relative volatilities. The order of volatilities for tocotrienols, based on the distribution coefficients, was desmethyl tocotrienols (??T3)>??tocotrienols (??T3)>??tocotrienols (??T3). The separation of tocotrienols from FFA approached maximum values only at low temperatures and fell

John Shi; Luidy Rodríguez Posada; Yukio Kakuda; Sophia Jun Xue

2007-01-01

437

Prevention against Oxidation of Mn Evaporant during Reactive Evaporation Process  

NASA Astrophysics Data System (ADS)

Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, during which its deposition rate deteriorates with increasing deposition run. So it is difficult to maintain the stoichiometry of films from run to run. To prevent deteriorations, a quartz ampoule has been installed at the bottom of the Mn crucible, which isolated successfully the Mn evaporant from incoming oxygen atoms. It improved the reproducibility of film composition because of stabilizing of the deposition rate. The performance of quartz ampoule was compared with that of Mo separator and stainless steel (SUS) cell.

Isai, Masaaki; Fujiyasu, Hiroshi

2001-11-01

438

Why is There an Evaporation Minimum at the Equator?  

Microsoft Academic Search

At all longitudes oceanic evaporation rates are lower on the equator than at latitudes to the north and south. Over the oceanic cold tongues this is related to the presence of cold water and divergence of heat by the ocean circulation. Herein is investigated why there is also a minimum over the Indo-Pacific warm pool. Model results confirm the recent

Richard Seager; Ragu Murtugudde; Amy Clement; Celine Herweijer

2003-01-01

439

An evaporation model of colloidal suspension droplets  

NASA Astrophysics Data System (ADS)

Colloidal suspensions of polymers in water or other solvents are widely used in the pharmaceutical industry to coat tablets with different agents. These allow controlling the rate at which the drug is delivered, taste or physical appearance. The coating is performed by simultaneously spraying and drying the tablets with the colloidal suspension at moderately high temperatures. The spreading of the coating on the pills surface depends on the droplet Webber and Reynolds numbers, angle of impact, but more importantly on the rheological properties of the drop. We present a model for the evaporation of a colloidal suspension droplet in a hot air environment with temperatures substantially lower than the boiling temperature of the carrier fluid. As the liquid vaporizes from the surface, a compacting front advances into the droplet faster than the liquid surface regresses, forming a shell of a porous medium where the particles reach their maximum packing density. While the surface regresses, the evaporation rate is determined by both the rate at which heat is transported to the droplet surface and the rate at which liquid vapor is diffused away from it. This regime continues until the compacting front reaches the center of the droplet, at which point the evaporation rate is drastically reduced.

Sartori, Silvana; Li\\ Nán, Amable; Lasheras, Juan C.

2009-11-01

440

Experimental Investigation of Microstructured Evaporators  

NASA Astrophysics Data System (ADS)

Microfluidic devices have become more and more popular over the last decades [1]. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible [2]. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results [2] for the evaporation of R134a in straight microchannels.

Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

2012-11-01

441

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

Microsoft Academic Search

The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an

D Tamburello; R Richard Dimenna; S Si Lee

2009-01-01

442

Effectiveness of Conservation-Oriented Water Rates in Tucson  

Microsoft Academic Search

In arid regions such as the American Southwest, various measures have been implemented to help reduce water use. In this article, the author examines the effectiveness of an inverted (increasing-block) rate structure as a means of enhancing an already ambitious water conservation program in Tucson, Ariz. Use patterns of single-family residential customers during a nine-year period are analyzed, with a

Richard W. Cuthbert

1989-01-01

443

Measurement of the rate of water translocation through carbon nanotubes.  

PubMed

We present an approach for measuring the water flow rate through individual ultralong carbon nanotubes (CNTs) using field effect transistors array defined on individual tubes. Our work exhibits a rate enhancement of 882-51 and a slip length of 53-8 nm for CNTs with diameters of 0.81-1.59 nm. We also found that the enhancement factor does not increase monotonically with shrinking tube diameter and there exists a discontinuous region around 0.98-1.10 nm. We believe that these single-tube level results would help understand the intrinsic nanofluidics of water in CNTs. PMID:21462938

Qin, Xingcai; Yuan, Quanzi; Zhao, Yapu; Xie, Shubao; Liu, Zhongfan

2011-04-04

444

Photoluminescence and anti-deliquesce of cesium iodide and its sodium-doped films deposited by thermal evaporation at high deposition rates  

NASA Astrophysics Data System (ADS)

Cesium iodide (CsI) and sodium iodide (NaI) are good scintillators due to their high luminescence efficiency. These alkali halides can be excited by ultra-violet or by ionizing radiation. In this study, CsI and its Na-doped films about 8 ?m thick were deposited by thermal evaporation boat without heating substrates at high deposition rates of 30, 50, 70, 90, and 110 nm/sec, respectively. The as-deposited films were sequentially deposited a silicon dioxide film to protect from deliquesce. And, the films were also post-annealed in vacuum at 150, 200, 250, and 300 °C, respectively. We calculated the packing densities of the samples according to the measurements of Fourier transform infrared spectroscopy (FTIR) and observed the luminescence properties by photoluminescence (PL) system. The surfaces and cross sections of the films were investigated by scanning electron microscope (SEM). From the above measurements we can find the optimal deposition rate of 90 nm/sec and post-annealing temperature of 250 °C in vacuum for the asdeposited cesium iodide and its sodium-doped films.

Hsu, Jin-Cherng; Chiang, Yueh-Sheng; Ma, Yu-Sheng

2013-03-01

445

DEGRADATION RATE OF WATER-SOLUBLE POLYMERS BY OZONE  

Microsoft Academic Search

Water-soluble polymers were degraded by ozone, and the degradation rate defined by the change of weight average polymerization degree per unit time was obtained. The degradation rate of poly(oxyethylene) (PEG) was proportional to the 1.5 to 2.0 power of the polymerization degree, and was 20 to 60 times that of poly(acrylamide) (PAAm). The experimental results of PEG and PAAm were

K. IKEMIZU; S. MOROOKA; Y. KATO

1985-01-01

446

Predicting oxygen transfer and water flow rate in airlift aerators  

Microsoft Academic Search

Water flow rate, gas-phase holdup, and dissolved oxygen (DO) profiles are measured in a full-scale airlift aerator as a function of applied air flow rate. A model that predicts oxygen transfer based on discrete-bubble principles is applied. The riser DO profiles are used to calculate the initial bubble size. The range of calculated bubble diameters obtained using the model is

Vickie L Burris; Daniel F McGinnis; John C Little

2002-01-01

447

HAPEX-MOBLIHY: A Hydrologic Atmospheric Experiment for the Study of Water Budget and Evaporation Flux at the Climatic Scale  

Microsoft Academic Search

The HAPEX-MOBILHY program is aimed at studying the hydrological budget and evaporation flux at the scale of a GCM (general circulation model) grid square, i.e., 104 km2. Different surface and subsurface networks will be operated during the year 1986, to measure and monitor soil moisture, surface-energy budget and surface hydrology, as well as atmospheric properties.A two-and-a-half-month special observing period will

Jean-Claude André; Jean-Paul Goutorbe; Alain Perrier

1986-01-01

448

Modelling of heat and mass transfer in a horizontal-tube falling-film evaporator for water desalination  

Microsoft Academic Search

In this study, heat and mass transfer in a horizontal-tube falling-film evaporator, destined to be used in a desalination plant functioning by aero-evapo-condensation process, is studied theoretically. The present exchanger is made of polypropylene and it was designed to work at low temperatures (60°C–90°C) utilising geothermal energy. The one-dimensional model developed, uses basic aerodynamic, hydrodynamic and heat\\/mass transfer information to

K. Bourouni; R. Martin; L. Tadrist; H. Tadrist

1998-01-01

449

RATES, CONSTANTS, AND KINETICS FORMULATIONS IN SURFACE WATER QUALITY MODELING  

EPA Science Inventory

Recent studies are reviewed to provide a comprehensive volume on state-of-the-art formulations used in surface water quality modeling along with accepted values for rate constants and coefficients. Topics covered include system geometric representation (spatial and temporal), phy...

450

Counterion evaporation  

SciTech Connect

We study the adsorption behavior of a highly charged rodlike polyelectrolyte approaching an oppositely charged planar wall in an unbounded electrolyte solution. The grand potential, the entropy, and the total number of screening particles are calculated as functions of the rod-wall distance, using input parameters that are typical of a DNA-molecule and charged lipid bilayers. It is found that counterions which are bound to the polyelectrolyte at infinite rod-wall distances will be released, or {open_quotes}evaporated,{close_quotes} as the DNA molecule moves closer to the charged wall. This effect can be regarded as the opposite of the ion-condensation process. The transition of ions from the system of screening ions into the reservoir of bulk ions can lead to an increase of the enthalpy. This gain of enthalpy for the whole system manifests itself as an attractive contribution to the effective interaction between the wall and the polyelectrolyte.

Fleck, C.; von Grunberg, H. H.

2001-06-01

451

Homogeneous nucleation rate measurements in supersaturated water vapor  

NASA Astrophysics Data System (ADS)

The rate of homogeneous nucleation in supersaturated vapors of water was studied experimentally using a thermal diffusion cloud chamber. Helium was used as a carrier gas. Our study covers a range of nucleation rates from 3×10-1 to 3×102 cm-3 s-1 at four isotherms: 290, 300, 310, and 320 K. The molecular content of critical clusters was estimated from the slopes of experimental data. The measured isothermal dependencies of nucleation rate of water on saturation ratio were compared with the prediction of the classical theory of homogeneous nucleation, the empirical prediction of Wölk et al. [J. Chem. Phys. 117, 10 (2002)], the scaled model of Hale [Phys. Rev. A 33, 4156 (1986)], and the former nucleation onset data.

Brus, David; Ždímal, Vladimír; Smolík, Ji?í

2008-11