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1

Objective Forecasting of Pan Evaporation - Two Contributions.  

National Technical Information Service (NTIS)

This memorandum consists of two articles on forecasting of pan evaporation. The first, An Aid to Agricultural Evaporation Forecasting, offers a linear equation which estimates 24-hour pan evaporation as a function of means of temperature, relative humidit...

N. P. Cimino J. B. Graham

1976-01-01

2

Design and Testing of a Mini Class A Evaporation Pan.  

National Technical Information Service (NTIS)

This report presents the results of a design and testing effort to develop an evaporation pan which is smaller than the Class A evaporation pan but which will produce an evaporation rate similar to that from a Class A pan. An energy balance simulation was...

A. Vassar L. Pochop V. Hasfurther

1987-01-01

3

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

4

7 CFR 58.913 - Evaporators and vacuum pans.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913 Agriculture... § 58.913 Evaporators and vacuum pans. All equipment used in the removal...and Milk Products Evaporators and Vacuum...

2009-01-01

5

7 CFR 58.913 - Evaporators and vacuum pans.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Evaporators and vacuum pans. 58.913 Section 58.913 Agriculture... § 58.913 Evaporators and vacuum pans. All equipment used in the removal...and Milk Products Evaporators and Vacuum...

2010-01-01

6

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 gL-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

7

Changes in Australian pan evaporation from 1970 to 2002  

Microsoft Academic Search

Contrary to expectations, measurements of pan evaporation show decreases in many parts of the Northern Hemisphere over the last 50 years. When combined with rainfall measurements, these data show that much of the Northern Hemisphere's terrestrial surface has become less arid over the last 50 years. However, whether the decrease in pan evaporation is a phenomenon limited to the Northern

Michael L. Roderick; Graham D. Farquhar

2004-01-01

8

Pan Evaporation, Relative Humidity and Daily Minimum/Maximum Temperatures  

NSDL National Science Digital Library

This activity will show students how to determine rate of evaporation and the atmospheric factors that can affect this rate. Laboratory equipment needed for this investigation includes: a digital balance or triple beam balance, metric ruler in millimeter graduations, level, 2 metal pans, barograph (or barometer), hydrograph (or hygrometer), thermograph (or thermometer), anemometer, rain gauges and quart jar. Teacher background information, assessment suggestions, and a scoring rubric are included. This is Activity 1, in the learning module, Water: Here, There and Everywhere, part of the lesson series, The Potential Consequences of Climate Variability and Change.

9

Fortuitous Evaporation Pan Observations on the Alaskan North Slope  

NASA Astrophysics Data System (ADS)

Evapotranspiration (ET) plays a significant role in the hydrologic cycle of all basins, yet is only occasionally measured in the Arctic. The energy environment surrounding the simple evaporation pan varies considerably from that of the natural environment. Yet, an evaporation pan, although simple in concept, is a sound way to estimate the potential ET and also determine an ET pan coefficient assuming there is also a complementary estimate of actual ET. The few existing ET estimates in the Arctic are based on water balance, energy balance and methods like the Priestley-Taylor method that require less input data. An evaporation pan was installed in 1986 on the North Slope of Alaska with the intention of collecting data for only 3 years; but in reality, pan evaporation data has been collected for 22 years at this Arctic site. The summer maximum, average, minimum and standard deviation are 420 mm, 324 mm, 280 mm and 40 mm, respectively from 1986 to 2008 (1989 missing). Both the water balance of the 2.2 km2 Imnavait Creek catchment and the Priestley-Taylor method were used to produce seasonal estimates of actual evapotranspiration. When used in conjunction with the pan evaporation measurements, a pan coefficient of 0.55 was found in both cases; a typical value for the pan coefficient in temperate regions is 0.5. The pan evaporation results can also be correlated with other measured variables (such as air temperature, net radiation, summer precipitation, etc.). For example, we see a very strong correlation (r2 > 0.94 for each of the 22 summer seasons) between pan evaporation amount and thawing degree days (TDD). This should not be too surprising as TDD is an indicator of the thermal regime side of the equation, but it does not account for the amount and timing of summer precipitation that has ranged from a seasonal low of 53 mm to a high of 342 mm at Imnavait Creek.

Mumm, J. P.; Kane, D. L.

2010-12-01

10

Modeling of daily pan evaporation using partial least squares regression  

Microsoft Academic Search

This study presented the application of partial least squares regression (PLSR) in estimating daily pan evaporation by utilizing\\u000a the unique feature of PLSR in eliminating collinearity issues in predictor variables. The climate variables and daily pan\\u000a evaporation data measured at two weather stations located near Elephant Butte Reservoir, New Mexico, USA and a weather station\\u000a located in Shanshan County, Xinjiang,

Shalamu Abudu; ChunLiang Cui; J. Phillip King; Jimmy Moreno; A. Salim Bawazir

2011-01-01

11

Changes of Pan Evaporation in the West of Iran  

Microsoft Academic Search

Evaporation is an important component of the hydrological cycle and its change would be of great significance for water resources\\u000a planning, irrigation control and agricultural production. The main purpose of this study was to investigate temporal variations\\u000a in pan evaporation (Epan) and the associated changes in maximum (Tmax), mean (Tmean) and minimum (Tmin) air temperatures and precipitation (P) for 12

Hossein Tabari; Safar Marofi

2011-01-01

12

Use of pan evaporation to estimate terrestrial evaporation trends: The case of the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

There is still no general agreement on the relationship between the evaporation of open water from a small pan and the terrestrial evaporation from the surrounding landscape under drying conditions. A possible way out of this impasse is reviewed and applied to the harsh and extreme climatic conditions of the Tibetan Plateau. It is confirmed herein that during 1966-2000 with a pan evaporation trend of -4.57 mm a-2, the terrestrial evaporation trend was +0.7 mm a-2, in agreement with the experimental findings of Zhang et al. (2007).

Brutsaert, Wilfried

2013-05-01

13

Modeling Pan Evaporation for Kuwait by Multiple Linear Regression  

PubMed Central

Evaporation is an important parameter for many projects related to hydrology and water resources systems. This paper constitutes the first study conducted in Kuwait to obtain empirical relations for the estimation of daily and monthly pan evaporation as functions of available meteorological data of temperature, relative humidity, and wind speed. The data used here for the modeling are daily measurements of substantial continuity coverage, within a period of 17 years between January 1993 and December 2009, which can be considered representative of the desert climate of the urban zone of the country. Multiple linear regression technique is used with a procedure of variable selection for fitting the best model forms. The correlations of evaporation with temperature and relative humidity are also transformed in order to linearize the existing curvilinear patterns of the data by using power and exponential functions, respectively. The evaporation models suggested with the best variable combinations were shown to produce results that are in a reasonable agreement with observation values.

Almedeij, Jaber

2012-01-01

14

A simulation model for predicting hourly pan evaporation from meteorological data  

NASA Astrophysics Data System (ADS)

The objective of this study was to develop and validate a simulation model of the evaporation rate of a Class A evaporimeter pan ( Epan). A multilayer model was first developed, based on the discretization of the pan water volume into several layers. The energy balance equations established at the water surface and within the successive in-depth layers were solved using an iterative numerical scheme. The wind function at the pan surface was identified from previous experiments, and the convective processes within the tank were accounted for by introducing an internal 'mixing' function which depends on the wind velocity. The model was calibrated and validated using hourly averaged measurements of the evaporation rate and water temperature, collected in a Class A pan located near Cartagena (Southeast Spain). The simulated outputs of both water temperature and Epan proved to be realistic when compared to the observed values. Experimental data evidenced that the convective mixing process within the water volume induced a rapid homogenization of the temperature field within the whole water body. This result led us to propose a simplified version of the multilayer model, assuming an isothermal behavior of the pan. The outputs of the single layer model are similar to those supplied by the multilayer model although slightly less accurate. Due to its good predictive performances, facility of use and implementation, the simplified model may be proposed for applied purposes, such as routine prediction of Class A pan evaporation, while the multilayer model appears to be more appropriate for research purposes.

Molina Martnez, J. M.; Martnez Alvarez, V.; Gonzlez-Real, M. M.; Baille, A.

2006-03-01

15

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture ...Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers shall...

2010-01-01

16

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture ...Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers shall...

2009-01-01

17

Rate of runaway evaporative cooling  

NASA Astrophysics Data System (ADS)

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.

van de Groep, J.; van der Straten, P.; Vogels, J. M.

2011-09-01

18

Preliminary results of comparative measurements of different types of internationally employed evaporation pans  

Microsoft Academic Search

Using 5-year measuring series carried out within the scope of the International Hydrological Decade at the stations Stechlinsee and Goldberg, comparison measurements were made between international types of evaporation pans and preliminary results concerning the typical behavior of the various pans have been found, with the locality features being taken into account. The major concern of the studies were the

D. Richter

1975-01-01

19

Estimating actual, potential, reference crop and pan evaporation using standard meteorological data: a pragmatic synthesis  

NASA Astrophysics Data System (ADS)

This guide to estimating daily and monthly actual, potential, reference crop and pan evaporation covers topics that are of interest to researchers, consulting hydrologists and practicing engineers. Topics include estimating actual evaporation from deep lakes and from farm dams and for catchment water balance studies, estimating potential evaporation as input to rainfall-runoff models, and reference crop evapotranspiration for small irrigation areas, and for irrigation within large irrigation districts. Inspiration for this guide arose in response to the authors' experiences in reviewing research papers and consulting reports where estimation of the actual evaporation component in catchment and water balance studies was often inadequately handled. Practical guides using consistent terminology that cover both theory and practice are not readily available. Here we provide such a guide, which is divided into three parts. The first part provides background theory and an outline of the conceptual models of potential evaporation of Penman, Penman-Monteith and Priestley-Taylor, as well as discussions of reference crop evapotranspiration and Class-A pan evaporation. The last two sub-sections in this first part include techniques to estimate actual evaporation from (i) open-surface water and (ii) landscapes and catchments (Morton and the advection-aridity models). The second part addresses topics confronting a practicing hydrologist, e.g. estimating actual evaporation for deep lakes, shallow lakes and farm dams, lakes covered with vegetation, catchments, irrigation areas and bare soil. The third part addresses six related issues: (i) automatic (hard wired) calculation of evaporation estimates in commercial weather stations, (ii) evaporation estimates without wind data, (iii) at-site meteorological data, (iv) dealing with evaporation in a climate change environment, (v) 24 h versus day-light hour estimation of meteorological variables, and (vi) uncertainty in evaporation estimates. This paper is supported by a Supplement that includes 21 sections enhancing the material in the text, worked examples of many procedures discussed in the paper, a program listing (Fortran 90) of Morton's WREVAP evaporation models along with tables of monthly Class-A pan coefficients for 68 locations across Australia and other information.

McMahon, T. A.; Peel, M. C.; Lowe, L.; Srikanthan, R.; McVicar, T. R.

2013-04-01

20

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

NASA Astrophysics Data System (ADS)

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 the test. The findings revealed a number of misconceptions, many of which have not been previously documented. The results have implications for tertiary level teaching suggesting that a substantial review of teaching strategies is needed.

Canpolat, Nurta

2006-12-01

21

Assessment of alkaliphilic haloarchaeal diversity in Sua pan evaporator ponds in Botswana  

Microsoft Academic Search

Cultivation-dependent and molecular-based culture-independent methods were used to assess alkaliphilic haloarchaeal diversity at Sua pan evaporator ponds in Botswana. Isolates belonging to the genera Natrialba, Natronococcus and Natronorubrum were recovered from brine samples by enrichment and identified through a series of biochemical tests as well as sequencing of 16S rRNA fragments. In addition, an environmental 16S rRNA library was constructed

Ashant Pravin Gareeb; Mathabatha Evodia Setati

2009-01-01

22

Estimating daily pan evaporation using artificial neural network in a semi-arid environment  

NASA Astrophysics Data System (ADS)

The objective of this study was to test an artificial neural network (ANN) for estimating the evaporation from pan ( E Pan) as a function of air temperature data in the Safiabad Agricultural Research Center (SARC) located in Khuzestan plain in the southwest of Iran. The ANNs (multilayer perceptron type) were trained to estimate E Pan as a function of the maximum and minimum air temperature and extraterrestrial radiation. The data used in the network training were obtained from a historical series (1996-2001) of daily climatic data collected in weather station of SARC. The empirical Hargreaves equation (HG) is also considered for the comparison. The HG equation calibrated for converting grass evapotranspiration to open water evaporation by applying the same data used for neural network training. Two historical series (2002-2003) were utilized to test the network and for comparison between the ANN and calibrated Hargreaves method. The results show that both empirical and neural network methods provided closer agreement with the measured values ( R 2 > 0.88 and RMSE < 1.2 mm day-1), but the ANN method gave better estimates than the calibrated Hargreaves method.

Rahimikhoob, Ali

2009-09-01

23

Black Hole Evaporation Rates without Spacetime  

NASA Astrophysics Data System (ADS)

Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobsons 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem.

Braunstein, Samuel L.; Patra, Manas K.

2011-08-01

24

Black hole evaporation rates without spacetime.  

PubMed

Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson's 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem. PMID:21902381

Braunstein, Samuel L; Patra, Manas K

2011-08-12

25

Evaluation of pan evaporation modeling with two different neural networks and weather station data  

NASA Astrophysics Data System (ADS)

This study evaluates neural networks models for estimating daily pan evaporation for inland and coastal stations in Republic of Korea. A multilayer perceptron neural networks model (MLP-NNM) and a cascade correlation neural networks model (CCNNM) are developed for local implementation. Five-input models (MLP 5 and CCNNM 5) are generally found to be the best for local implementation. The optimal neural networks models, including MLP 4, MLP 5, CCNNM 4, and CCNNM 5, perform well for homogeneous (cross-stations 1 and 2) and nonhomogeneous (cross-stations 3 and 4) weather stations. Statistical results of CCNNM are better than those of MLP-NNM during the test period for homogeneous and nonhomogeneous weather stations except for MLP 4 being better in BUS-DAE and POH-DAE, and MLP 5 being better in POH-DAE. Applying the conventional models for the test period, it is found that neural networks models perform better than the conventional models for local, homogeneous, and nonhomogeneous weather stations.

Kim, Sungwon; Singh, Vijay P.; Seo, Youngmin

2013-08-01

26

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

27

PREDICTING EVAPORATION RATES AND TIMES FOR SPILLS OF CHEMICAL MIXTURES  

EPA Science Inventory

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, includ...

28

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

29

Evaporation Rates of Brine on Mars  

NASA Technical Reports Server (NTRS)

While Mars is now largely a dry and barren place, recent data have indicated that water has flowed at specific locations within the last approx. 10(exp 6) y. This had led to a resurgence of interest in theoretical and experimental work aimed at understanding the behavior of water on Mars. There are several means whereby the stability of liquid water on Mars could be increased, one being the presence solutes that would depress the freezing point. Salt water on Earth is about 0.5M NaCl, but laboratory experiments suggest that martian salt water is quite different. We recently began a program of laboratory measurements of the stability of liquid water, ice and ice-dust mixtures under martian conditions and here report measurements of the evaporation rate of 0.25M brine.

Sears, D. W. G.; Chittenden, J.; Moore, S. R.; Meier, A.; Kareev, M.; Farmer, C. B.

2004-01-01

30

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

31

[Optimal irrigation index for cotton drip irrigation under film mulching based on the evaporation from pan with constant water level].  

PubMed

A field experiment with two irrigation cycles and two irrigating water quotas at squaring stage and blossoming-boll forming stage was conducted in Urumqi of Xinjiang Autonomous Region, Northwest China in 2008-2009, aimed to explore the high-efficient irrigation index of cotton drip irrigation under film mulching. The effects of different water treatments on the seed yield, water consumption, and water use efficiency (WUE) of cotton were analyzed. In all treatments, there was a high correlation between the cotton water use and the evaporation from pan installed above the plant canopy. In high-yield cotton field (including the treatment T4 which had 10 days and 7 days of irrigation cycle with 30.0 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2008, and the treatment T1 having 7 days of irrigation cycle with 22.5 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2009), the pan-crop coefficient (Kp) at seedling stage, squaring stage, blossoming-boll forming stage, and boll opening stage was 0.29-0.30, 0.52-0.53, 0.74-0.88, and 0.19-0.20, respectively. As compared with the other treatments, T4 had the highest seed cotton yield (5060 kg x hm(-2)) and the highest WUE (1.00 kg x m(-3)) in 2008, whereas T1 had the highest seed cotton yield (4467 kg x hm(-2)) and the highest WUE (0.99 kg x m(-3)) in 2009. The averaged cumulative pan evaporation in 7 days and 10 days at squaring stage was 40-50 mm and 60-70 mm, respectively, and that in 7 days at blossoming-boll forming stage was 40-50 mm. It was suggested that in Xinjiang cotton area, irrigating 45 mm water for seedling emergence, no irrigation both at seedling stage and at boll opening stage, and irrigation was started when the pan evaporation reached 45-65 mm and 45 mm at squaring stage and blossoming-boll stage, respectively, the irrigating water quota could be determined by multiplying cumulative pan evaporation with Kp (the Ko was taken as 0.5, 0.75, 0.85, and 0.75 at squaring stage, early blossoming, full-blossoming, and late blossoming stage, respectively), which could be the high efficient irrigation index to obtain high yield and WUE in drip irrigation cotton field and to save irrigation water resources. PMID:24564144

Shen, Xiao-Jun; Zhang, Ji-Yang; Sun, Jing-Sheng; Gao, Yang; Li, Ming-Si; Liu, Hao; Yang, Gui-Sen

2013-11-01

32

Fuzzy logic model approaches to daily pan evaporation estimation in western Turkey  

Microsoft Academic Search

Evaporation is one of the fundamental elements in the hydrological cycle, which affects the yield of river basins, the capacity of reservoirs, the consumptive use of water by crops and the yield of underground supplies. In general, there are two approaches in the evaporation estimation, namely, direct and indirect. The indirect methods such as the Penman and Priestley-Taylor methods are

M. EROL

33

PLS regression-based pan evaporation and minimum-maximum temperature projections for an arid lake basin in India  

NASA Astrophysics Data System (ADS)

Climate change information required for impact studies is of a much finer scale than that provided by Global circulation models (GCMs). This paper presents an application of partial least squares (PLS) regression for downscaling GCMs output. Statistical downscaling models were developed using PLS regression for simultaneous downscaling of mean monthly maximum and minimum temperatures ( T max and T min) as well as pan evaporation to lake-basin scale in an arid region in India. The data used for evaluation were extracted from the NCEP/NCAR reanalysis dataset for the period 1948-2000 and the simulations from the third-generation Canadian Coupled Global Climate Model (CGCM3) for emission scenarios A1B, A2, B1, and COMMIT for the period 2001-2100. A simple multiplicative shift was used for correcting predictand values. The results demonstrated that the downscaling method was able to capture the relationship between the premises and the response. The analysis of downscaling models reveals that (1) the correlation coefficient for downscaled versus observed mean maximum temperature, mean minimum temperature, and pan evaporation was 0.94, 0.96, and 0.89, respectively; (2) an increasing trend is observed for T max and T min for A1B, A2, and B1 scenarios, whereas no trend is discerned with the COMMIT scenario; and (3) there was no trend observed in pan evaporation. In COMMIT scenario, atmospheric CO2 concentrations are held at year 2000 levels. Furthermore, a comparison with neural network technique shows the efficiency of PLS regression method.

Goyal, Manish Kumar; Ojha, C. S. P.

2011-10-01

34

A Moisture-limited ET Upper Bound and Its Application in an Evaporation Pan Based Complementary-relationship Model for ET Estimation  

NASA Astrophysics Data System (ADS)

Long-term evaporation pan observations worldwide constitute a good database to study effects of climate change. In many cases, however, actual evapotranspiration rather than pan evapotranspiration is of interest. In order to estimate land surface evapotranspiration based on pan observations, a relationship between pan evaporation and its surrounding actual evapotranspiration (ET) must be found. A complementary relationship has been developed in previous studies and is formulated as Epan = Ep + b(Ep-Ea), where Epan, Ep and Ea are pan evaporation, potential evaporation due to local radiation energy input, and actual areal evapotranspiration, respectively. We explore this model, based on long-term observations at seven evaporation pan sites in South Australia. Interestingly, we observe a clear edge in the lower-left corner of the data cloud in the (1/Ep, Epan/Ep) space for most months. This clear edge line is most likely caused by an upper bound in daily ET, which is observed at multiple AmeriFlux sites of various land covers. This upper bound in daily ET is likely associated with radiative energy partitioning and different timing of surface and root-zone soil wetting. It is simulated with physically-based numerical modelling at a vegetated semiarid environment. This upper bound in daily ET provides a mathematical basis for the lower edge in the (1/Ep, Epan/Ep) space. This edge line, when determined, can be used to estimate monthly b values. An automatic regression approach is presented to objectively determine the lower-left edge line. Preliminary calculation of Ea with the estimated b, appears to provide reasonable values for the three pan sites in areas with mean annual precipitation around and above 500 mm. We also examine under what a range of climate and surface conditions this upper ET bound exists. The significance of this phenomenon is not only in application of this evaporation pan based complementary-relationship method, but also in application of remote sensing ET methods with temporal extrapolation using the evaporative fraction, and in understanding catchment water balance and ecosystem water use efficiency. The regression-fit lower-left edge lines for estimating monthly b values at an evaporation pan site (Australia Bureau of Meteorology ID 26021). The intercept of each line is equal to b+1. The upper bound of daily ET for the month can be calculated from the slope (= -b*Ea).(The lines of positive slopes for some winter months are artefact of low resolution of pan evaporation measurements).

Guan, H.; Cook, P. G.; Simmons, C. T.; Brunner, P.; Gutierrez-Jurado, H. A.; Wang, H.

2013-12-01

35

Simulation of temporal and spatial distribution of required irrigation water by crop models and the pan evaporation coefficient method  

NASA Astrophysics Data System (ADS)

Hebei Plain is the most important agricultural belt in North China. Intensive irrigation, low and uneven precipitation have led to severe water shortage on the plain. This study is an attempt to resolve this crucial issue of water shortage for sustainable agricultural production and water resources management. The paper models distributed regional irrigation requirement for a range of cultivated crops on the plain. Classic crop models like DSSAT- wheat/maize and COTTON2K are used in combination with pan-evaporation coefficient method to estimate water requirements for wheat, corn, cotton, fruit-trees and vegetables. The approach is more accurate than the static approach adopted in previous studies. This is because the combination use of crop models and pan-evaporation coefficient method dynamically accounts for irrigation requirement at different growth stages of crops, agronomic practices, and field and climatic conditions. The simulation results show increasing Required Irrigation Amount (RIA) with time. RIA ranges from 5.08109 m3 to 14.42109 m3 for the period 1986~2006, with an annual average of 10.6109 m3. Percent average water use by wheat, fruit trees, vegetable, corn and cotton is 41%, 12%, 12%, 11%, 7% and 17% respectively. RIA for April and May (the period with the highest irrigation water use) is 1.78109 m3 and 2.41109 m3 respectively. The counties in the piedmont regions of Mount Taihang have high RIA while the central and eastern regions/counties have low irrigation requirement.

Yang, Yan-Min; Yang, Yonghui; Han, Shu-Min; Hu, Yu-Kun

2009-07-01

36

Modelling a model?!! Prediction of observed and calculated daily pan evaporation in New Mexico, U.S.A.  

NASA Astrophysics Data System (ADS)

Data-driven modelling is most commonly used to develop predictive models that will simulate natural processes. This paper, in contrast, uses Gene Expression Programming (GEP) to construct two alternative models of different pan evaporation estimations by means of symbolic regression: a simulator, a model of a real-world process developed on observed records, and an emulator, an imitator of some other model developed on predicted outputs calculated by that source model. The solutions are compared and contrasted for the purposes of determining whether any substantial differences exist between either option. This analysis will address recent arguments over the impact of using downloaded hydrological modelling datasets originating from different initial sources i.e. observed or calculated. These differences can be easily be overlooked by modellers, resulting in a model of a model developed on estimations derived from deterministic empirical equations and producing exceptionally high goodness-of-fit. This paper uses different lines-of-evidence to evaluate model output and in so doing paves the way for a new protocol in machine learning applications. Transparent modelling tools such as symbolic regression offer huge potential for explaining stochastic processes, however, the basic tenets of data quality and recourse to first principles with regard to problem understanding should not be trivialised. GEP is found to be an effective tool for the prediction of observed and calculated pan evaporation, with results supported by an understanding of the records, and of the natural processes concerned, evaluated using one-at-a-time response function sensitivity analysis. The results show that both architectures and response functions are very similar, implying that previously observed differences in goodness-of-fit can be explained by whether models are applied to observed or calculated data.

Beriro, D. J.; Abrahart, R. J.; Nathanail, C. P.

2012-04-01

37

Urban evaporation rates for water-permeable pavements.  

PubMed

In urban areas the natural water balance is disturbed. Infiltration and evaporation are reduced, resulting in a high surface runoff and a typical city climate, which can lead to floods and damages. Water-permeable pavements have a high infiltration rate that reduces surface runoff by increasing the groundwater recharge. The high water retention capacity of the street body of up to 51 l/m(2) and its connection via pores to the surface lead to higher evaporation rates than impermeable surfaces. A comparison of these two kinds of pavements shows a 16% increase in evaporation levels of water-permeable pavements. Furthermore, the evaporation from impermeable pavements is linked directly to rain events due to fast-drying surfaces. Water-permeable pavements show a more evenly distributed evaporation after a rain event. Cooling effects by evaporative heat loss can improve the city climate even several days after rain events. On a large scale use, uncomfortable weather like sultriness or dry heat can be prevented and the urban water balance can be attenuated towards the natural. PMID:20818060

Starke, P; Gbel, P; Coldewey, W G

2010-01-01

38

Ultra-high cooling rate utilizing thin film evaporation  

PubMed Central

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50??m. Experimental results showed that a cooling rate of approximately 5104?C/min was achieved in a temperature range from 10?C to ?187?C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants.

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-hung; Tian, Bohan

2012-01-01

39

Ultra-high cooling rate utilizing thin film evaporation.  

PubMed

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50??m. Experimental results showed that a cooling rate of approximately 5[Formula: see text]10(4)?C/min was achieved in a temperature range from 10?C to -187?C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants. PMID:23093807

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-Hung; Tian, Bohan

2012-09-10

40

Ultra-high cooling rate utilizing thin film evaporation  

NASA Astrophysics Data System (ADS)

This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50 ?m. Experimental results showed that a cooling rate of approximately 5104 C/min was achieved in a temperature range from 10 C to -187 C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants.

Su, Fengmin; Ma, Hongbin; Han, Xu; Chen, Hsiu-hung; Tian, Bohan

2012-09-01

41

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

42

Studies on the evaporation of crude oil and petroleum products: I. the relationship between evaporation rate and time  

Microsoft Academic Search

The time dependance of evaporation was studied for several crude oils and petroleum oil products. Evaporation was determined by weight loss measured on a balance and recorded constantly on a computer. Examination of the data shows that most oil and petroleum products evaporate at a logarithmic rate with respect to time. This is attributed to the overall logarithmic appearance of

Merv F. Fingas

1997-01-01

43

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

44

Evaporation of forsterite in the primordial solar nebula; rates and accompanied isotopic fractionation  

Microsoft Academic Search

Evaporation rates of forsterite in the primordial solar nebula were modeled. There are 3 evaporation regimes expected: 1. free evaporation-dominated (FED) regime, where forsterite evaporates as free evaporation, 2. hydrogen reaction-dominated (HRD) regime, where the evaporation is affected by H2 gas, and 3. H2O\\/H2 buffer-dominated (HBD) regime, where the evaporation is controlled by redox states buffered by the H2O\\/H2 ratio

Akira Tsuchiyama; Shogo Tachibana; Toshio Takahashi

1999-01-01

45

Soil water management implications during the constant rate and the falling rate stages of soil evaporation  

Microsoft Academic Search

Desorptivity is a soil physical term used to describe the ability of soil to lose water by evaporation. Theoretically, it has been established that evaporation of water from soil during the falling rate stage, when water becomes limiting, is proportional to the square root of time. The proportionality constant is called desorptivity. Using ten soils with different textures from different

Mensah Bonsu

1997-01-01

46

On the remote measurement of evaporation rates from bare wet soil under variable cloud cover  

NASA Technical Reports Server (NTRS)

Evaporation rates from a natural wet soil surface are calculated from an energy balance equation at 0.1-hour intervals. A procedure is developed for calculating the heat flux through the soil surface from a harmonic analysis of the surface temperature curve. The evaporation integrated over an entire 24-hour period is compared with daily evaporation rates obtained from published models.

Auer, S.

1976-01-01

47

Evaporation rates of pasture-mesquite vegetation in central Mexico  

NASA Astrophysics Data System (ADS)

The semiarid highlands of Queretaro, in central Mexico, are characterized by booming urban and industrial developments with increasing demand for water. Agriculture takes place in the valleys and the surrounding hills have different types of xeric to subtropical rangeland. Hills are unfit for agriculture and usually are managed for cattle production and fuelwood. However, recent studies suggest that some hill areas are important for groundwater recharge and if they are not protected, important water shortages are envisioned. A critical question involves the effects of land management practices on rangeland hydrologic processes. Evaporation (E), which includes plant and soil evaporation is the largest water loss from rangelands and few data are available for central Mexico. The objective of this study was to estimate E from a mesquite (Prosopis sp.) dominated vegetation using the eddy correlation and the Pennman-Monteith models. Measurements were made during 24 summer days of 2004 at a piedmont site at Amascala, Queretaro (1919 m, 20 41' N, 100 16' W). Long term annual rainfall is 568 137 mm. Shrub density was 770 plants per hectare and mean height was 1.8 m. The understory was composed by a mixture of annual and perennial grasses but their biomass was negligible. Agroforestry was the current land use of the site. Shrubs were pruned every 2 or 3 years to maintain its height and promote leafty regrowth. Goats usually browsed the mesquite canopy, but during the time of the study they were excluded from the area.The rainy season started on 15 May and measurements initiated on 1 June, five days after a severe hail storm. Although the mesquite canopy had a full developed canopy with leaf area index of 3.2 by this time, they lost approximately 70% of leaf area. May and June rainfall was 146 mm and 46 mm occurred during the measuring period. Throughout the measurement period E was coupled to global radiation and total evaporation was 73.8 mm. On cloudy days E ranged from 1.1 to 2.0 mm d-1, maximum E was 4.3 mm d-1 on sunny days and the average E was 3.1 mm d-1. Average daily E increased during the measuring period at a rate of 0.05 mm d-1 (r2=0.2, p<0.05). Data suggest that evaporation from a pasture-mesquite vegetation is an important component in the water balance considering the limited rainfall occurring.

Sosa, E. G.; Escobar, A. G.

2004-12-01

48

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

49

Distribution of evaporation rate on human body surface.  

PubMed

Relative humidity (R. H), vapour pressure (Psk) and evaporation rate (Esk) of the human skin surface were measured at 29 points by an evaporimeter at 25 degrees C, 28 degrees C, 31 degrees C, 34 degrees C and 37 degrees C of air temperature (Ta), with 35 +/- 10 % R. H and air velocity of less than 0.2 m/s. The skin temperatures and the body weight loss were also measured by thermography and electronic balance. Ten healthy female subjects aged 22-34 years, wearing brassiere and shorts, took a supine and a prone posture during experiment. Comparisons of the obtained Esk with the previous results of other studies showed that there were no definite differences among the measuring methods of Esk, while it is ascertained that the calibration of the results to some standard values such as weight loss were more important to get accurate values of Esk. Distribution patterns of Esk were almost the same in the insensible zone but they remarkably changed in the sweating zone. According to the regression analysis of Esk and Ta, 29 regions were classified into the following 9 groups which showed similar values and changes of Esk with the air temperature: 1) face, 2) front upper trunk, 3) back upper trunk, 4) front lower trunk, 5) back lower trunk, 6) arm, 7) leg, 8) hand and foot and 9) palm, sole and axilla. These results were discussed in relation to the contributing factors such as the number and the capacity of the sweat gland, the regional skin temperature and the pressure-sweat response and also in relation to the skin wettedness. PMID:1476561

Park, S J; Tamura, T

1992-11-01

50

Electron Beam Evaporation Source with Integrated Rate Control.  

National Technical Information Service (NTIS)

A certain portion of the vapour atoms produced in the electron beam evaporation source is ionized by the electron beam and, by means of the deflecting magnetic field around the beam source, projected to a measuring probe. Because of an ion current in the ...

G. Wulff

1985-01-01

51

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

52

Absolute evaporation rates of non-rotating neutral polycyclic aromatic hydrocarbon clusters  

NASA Astrophysics Data System (ADS)

Context. Clusters of polycyclic aromatic hydrocarbons (PAHs) have been proposed as candidates for evaporating very small grains, which are thought to be precursors of free-flying PAHs. Evaporation rates have been calculated so far only for species containing up to a few 100-C atoms, whereas interstellar PAH clusters could contain up to ~1000 C atoms. Aims: We present a method that generalises the calculation of the statistical evaporation rate of large PAH clusters and provides rates for species containing up to ~1000 C-atoms. Methods: The evaporation of non-rotating neutral homo-molecular PAH clusters containing up to 12 molecules from a family of highly symmetric compact PAHs is studied. Statistical calculations were performed and completed with molecular dynamics simulations at high internal energies to provide absolute values for the evaporation rate and distributions of kinetic energy released. The calculations used explicit atom-atom Lennard-Jones potentials in the rigid molecule approximation. A new method is proposed to take both inter- and intra-molecular vibrations into account. Results: Without any parameter adjustment, the calculated evaporation rates agree well with available experimental data. We find that the non-rotation assumption has a limited impact on the evaporation rates. The photostability of PAH clusters increases dramatically with the size of molecules in the clusters, and to a lesser extent with the number of molecules in the clusters. For values of the UV radiation field that are typical of the regions where evaporating very small grains are observed, the smallest clusters in this study (~50 C-atoms) are found to be quickly photo-evaporated, whereas the largest clusters (~1000 C-atoms) are photostable. Conclusions: Our results support the idea that large PAH clusters are good candidates for evaporating very small grains.

Montillaud, J.; Joblin, C.

2014-07-01

53

The influence of droplet evaporation on fuel-air mixing rate in a burner  

NASA Technical Reports Server (NTRS)

Experiments involving combustion of a variety of hydrocarbon fuels in a simple atmospheric pressure burner were used to evaluate the role of droplet evaporation in the fuel/air mixing process in liquid fuel spray flames. Both air-assist atomization and pressure atomization processes were studied; fuel/air mixing rates were determined on the basis of cross-section average oxygen concentrations for stoichiometric overall operation. In general, it is concluded that droplets act as point sources of fuel vapor until evaporation, when the fuel jet length scale may become important in determining nonuniformities of the fuel vapor concentration. In addition, air-assist atomizers are found to have short droplet evaporation times with respect to the duration of the fuel/air mixing process, while for the pressure jet atomizer the characteristic evaporation and mixing times are similar.

Komiyama, K.; Flagan, R. C.; Heywood, J. B.

1977-01-01

54

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

NASA Astrophysics Data System (ADS)

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 the HPP. The latent heat component detectable during stage 2 evaporation is then estimated from the heat balance residual. Although the accuracy of the estimated evaporation rate depends on many factors (i.e., location of sensor needles, soil texture), the theoretical limits of the HPP method have not been thoroughly evaluated. In the study presented, numerical simulations of the soil water evaporation process were conducted for a heat pulse line source to evaluate the capabilities of the HPP method using a high resolution grid (i.e., mm scale). Calculated temperatures at the depths of virtual sensor needles were used for the HPP method and measured subsurface evaporation rates were compared with simulated ones. The impacts of sensor needle depths were also evaluated for tri-needle (THPP) and penta-needle (PHPP) heat pulse probe configurations. Furthermore, the impact of soil texture was evaluated using coarse- and fine-textured soils. Numerical simulations including liquid water, soil water vapor flux and heat transport were conducted using the HYDRUS-1D code.

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

2009-12-01

55

The evaporative requirement for heat balance determines whole-body sweat rate during exercise under conditions permitting full evaporation  

PubMed Central

Although the requirements for heat dissipation during exercise are determined by the necessity for heat balance, few studies have considered them when examining sweat production and its potential modulators. Rather, the majority of studies have used an experimental protocol based on a fixed percentage of maximum oxygen uptake (%). Using multiple regression analysis, we examined the independent contribution of the evaporative requirement for heat balance (Ereq) and % to whole-body sweat rate (WBSR) during exercise. We hypothesised that WBSR would be determined by Ereq and not by %. A total of 23 males performed two separate experiments during which they exercised for 90 min at different rates of metabolic heat production (200, 350, 500 W) at a fixed air temperature (30C, n= 8), or at a fixed rate of metabolic heat production (290 W) at different air temperatures (30, 35, 40C, n= 15 and 45C, n= 7). Whole-body evaporative heat loss was measured by direct calorimetry and used to calculate absolute WBSR in grams per minute. The conditions employed resulted in a wide range of Ereq (131487 W) and % (1555%). The individual variation in non-steady-state (030 min) and steady-state (3090 min) WBSR correlated significantly with Ereq (P < 0.001). In contrast, % correlated negatively with the residual variation in WBSR not explained by Ereq, and marginally increased (?2%) the amount of total variability in WBSR described by Ereq alone (non-steady state: R2= 0.885; steady state: R2= 0.930). These data provide clear evidence that absolute WBSR during exercise is determined by Ereq, not by %. Future studies should therefore use an experimental protocol which ensures a fixed Ereq when examining absolute WBSR between individuals, irrespective of potential differences in relative exercise intensity.

Gagnon, Daniel; Jay, Ollie; Kenny, Glen P

2013-01-01

56

Evaporation rates of freely falling liquid nitrogen droplets in air  

SciTech Connect

The rates of heat transfer to individual droplets of liquid nitrogen falling freely in air were measured under different air temperatures similar to the conditions in a cryogenic freezing system. High-speed cinephotography was used to measure drop size and velocity. Experimental results of heat transfer rates to individual droplets were analyzed and the data were compared to those obtainable using other types of dimensionless correlations. Droplets of initial size range investigated (2.5-0.72 mm diameter) attained terminal velocities at distances of 4-6 cm freefall away from the drop generator tip. The velocity values used in the correlation of heat transfer data were averaged over the time traveled by individual droplet.

Awonorin, S.O.

1989-01-01

57

Evaporation rate from square capillaries limited by corner flow viscous losses  

NASA Astrophysics Data System (ADS)

High evaporation rates from soil surfaces are sustained by capillary flows drawing water from the receding drying front along liquid pathways in crevices of the pore space. With increasing depth of the drying front viscous losses add to growing gravitational head and at a certain depth overcome capillary drive and disrupt liquid pathways. Viscous losses are significant in fine textured media resulting in earlier capillary failure than predicted by gravity-capillary force balance. To reproduce limitations of viscous corner flow on evaporation rates from angular pores (capillaries) we imaged drying dynamics from a square shaped glass capillary using a high speed camera, to provide for detailed record on receding menisci and thickness of liquid corner films including detachment dynamics at the top of the capillary. Additionally, deposition patterns of dye delineated regions of high rates of phase change (evaporation) showing a decrease in drying rate with recession of menisci and films into the capillary due to increasing diffusive path and reduced gradients. Effects of viscous losses on evaporation dynamics were systematically evaluated by varying ratio of viscous, gravity and capillary forces using different liquids (water, ethanol and octane), capillary geometry (0.5 and 1.0 mm width), and flow rate and direction with respect to gravity (horizontal and vertical arrangement). Experimental results were compared with analytical solutions for corner flow considering viscous losses. Preliminary results indicate that the maximum (main) meniscus depth supporting corner flow is not only dependent on the effective conductivity behind the interfaces, but also on interfacial processes taking place at the very top of the capillary. The pore scale findings will be incorporated into macroscopic models for determining viscous losses from soils and for estimating elapsed times for transition from high capillary-sustained evaporation rates to diffusion limited rates.

Hoogland, F.; Lehmann, P.; Yiotis, A.; Or, D.

2012-04-01

58

RESEARCH NOTES: Rate of evaporation of thorium from carburized thoriated tungsten cathodes measured by activation analysis  

Microsoft Academic Search

The rate of evaporation of thorium from carburized thoriated tungsten cathodes has been measured by means of activation analysis at different temperatures. Values found are about ten times higher than those from previous measurements based on the saturated emission of a receptor wire.

H. Schmied; M. Dek

1965-01-01

59

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...

60

PREDICTIONS OF EVAPORATIVE LOSS RATES OF SOLUTES IN STAGNANT AND TURBENT WATERS IN RELATION TO RATES OF REFERENCE MATERIALS  

EPA Science Inventory

A previously published kinetic model for evaporative rates of substances into air leads to the estimation of the dependence of solute transfer coefficients on turbulence applied to the system. The ratios of the transfer coefficients of all solutes become insensitive to air turbul...

61

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 ratesdepend 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

62

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

63

Evaporation Rates for Liquid Water and Ice Under Current Martian Conditions  

NASA Technical Reports Server (NTRS)

A number of studies have been concerned with the evaporation rates under martian conditions in order to place limits on the possible survival time of both liquid water and ice exposed on the surface of Mars. Such studies also aid in assessing the efficacy of an overlying layer of dust or loose regolith material in providing a barrier to free evaporation and thus prolong the lifetime of water in locations where its availability to putative living organisms would be significant. A better quantitative understanding of the effects of phase changes of water in the near surface environment would also aid the evaluation of the possible role of water in the formation of currently observed features, such as gullies in cliff walls and relatively short-term changes in the albedo of small surface areas ('dark stains'). Laboratory measurements aimed at refinement of our knowledge of these values are described here. The establishment of accurate values for evaporation rates and their dependence on the physical conditions of temperature, pressure and energy input, is an important benchmark for the further investigation of the efficacy of barriers to free evaporation in providing a prolonged period of survival of the water, particularly as a liquid.

Sears, D. W. G.; Moore, S. R.; Meier, A.; Chittenden, J.; Kareev, M.; Farmer, C. B.

2004-01-01

64

Evaporation Rates of Chemical Warfare Agents Measured Using 5 CM Wind Tunnels. 2. Munitions Grade Sulfur Mustard From Sand.  

National Technical Information Service (NTIS)

The evaporation of sulfur mustard from sand was studied as a function of temperature, drop size and air flow rate, using the same instrumentation as prior studies on glass. The evaporation rate increased with higher temperature, drop size, and wind speed;...

C. A. Brevett C. V. Giannaras E. L. Maloney J. P. Myers R. G. Nickol

2009-01-01

65

Evaporative rate model for a natural convection glazed collector\\/regenerator  

Microsoft Academic Search

In this paper, a numerical method has been applied to model the water evaporation rate of a glazed collector\\/regenerator component of an open-cycle absorption refrigeration system. This two-dimensional model calculates local heat and mass-transfer coefficients as part of the solution. The air flow in the glazed channel is driven by the combined buoyancy of both heat and mass transfer (water

D. J. Nelson; B. D. Wood

1990-01-01

66

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 185C 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 40C. 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

67

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

68

76 FR 362 - Pan American Energy, LLC ; Supplemental Notice That Initial Market-Based Rate Filing Includes...  

Federal Register 2010, 2011, 2012, 2013

...Energy Regulatory Commission [Docket No. ER11-2398-000] Pan American Energy, LLC ; Supplemental Notice That Initial Market-Based...a supplemental notice in the above-referenced proceeding of Pan American Energy, LLC's application for market-based...

2011-01-04

69

Evaporation Rate Study and NDMA Formation from UDMH/NO2 Reaction Products  

NASA Technical Reports Server (NTRS)

Laboratory samples of uns-dimethylhydrazine (UDMH) fuel/oxidizer (nitrogen dioxide) non-combustion reaction products (UFORP) were prepared using a unique permeation tube technology. Also, a synthetic UFORP was prepared from UDMH, N-nitrosodimethylamine (NDMA), dimethylammonium nitrate, sodium nitrite and purified water. The evaporation rate of UFORP and synthetic UFORP was determined under space vacuum (approx 10(exp -3) Torr) at -40 ?C and 0 ?C. The material remaining was analyzed and showed that the UFORP weight and NDMA concentration decreased over time; however, NDMA had not completely evaporated. Over 85% of the weight was removed by subjecting the UFORP to 10(-3) Torr for 7 hours at -40 ?C and 4 hours at 0 ?C. A mixture of dimethylammonium nitrate and sodium nitrite formed NDMA at a rapid rate in a moist air environment. A sample of UFORP residue was analyzed for formation of NDMA under various conditions. It was found that NDMA was not formed unless nitrite was added.

Buchanan, Vanessa D.; Dee, Louis A.; Baker, David L.

2003-01-01

70

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 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

2013-12-01

71

Habitat-mediated shifts and plasticity in the evaporative water loss rates of two congeneric pit vipers (Squamata, Viperidae, Agkistrodon)  

Microsoft Academic Search

Question: Are increased rates of total evaporative water loss (TEWL) associated with evolutionary transitions from terrestrial to aquatic habitats? Do individuals acclimated to wet conditions demonstrate higher TEWL rates than those acclimated to dry conditions? Organisms: Individuals of the snake species Agkistrodon piscivorus (Viperidae; semi-aquatic) and Agkistrodon contortrix (terrestrial) collected from the Savannah River Site, Aiken, SC, USA. Methods: We

Daniel S. Moen; Christopher T. Winne; Robert N. Reed

72

Environmental and Groundwater Controls on Evaporation Rates of A Shallow Saline Lake in the Western Sandhills Nebraska, USA  

NASA Astrophysics Data System (ADS)

The western Sand Hills of Nebraska exhibit many shallow saline lakes that actively mediate groundwater-lake-atmospheric exchanges. The region is home to the largest stabilized dune field in the western hemisphere. Most of the lakes in the western Sand Hills region are saline and support a wide range of ecosystems. However, they are also highly sensitive to variability in evaporative and groundwater fluxes, which makes them a good laboratory to examine the effects of climate on the water balance of interdunal lakes. Despite being semiarid, little is known about the importance of groundwater-surface water interactions on evaporative rates, or the effects of changes in meteorological and energy forcings on the diel, and seasonal dynamics of evaporative fluxes. Our study is the first to estimate evaporation rates from one of the hundreds of shallow saline lakes that occur in the western Sand Hills region. We applied the energy balance Bowen ratio method at Alkali Lake, a typical saline western Sand Hills lake, over a three-year period (2007-2009) to quantify summer evaporation rates. Daily evaporation rates averaged 5.5 mm/day from July through September and were largely controlled by solar radiation on a seasonal and diel scales. Furthermore, the range of annual variability of evaporation rates was low. Although less pronounced, groundwater level effects on evaporation rates were also observed, especially from August through October when solar radiation was lower. The lake exhibits significant fluctuation in lake levels and combined with a shallow lake bed, large changes in lake surface area are observed. Our findings also show that with the onset of summer conditions, lake surface area can change very rapidly (e.g. 24% of its surface area or ~16.6 hectares were lost in less than ~2 months). In every year summer evaporation exceeded annual rainfall by an average of 28.2% suggesting that groundwater is a significant component of the lake water balance, it is important for sustaining life of surrounding ecosystems, and during the growing season it is transiently stored in the lake before it is rapidly lost to the atmosphere.

Peake, C.; Riveros-Iregui, D.; Lenters, J. D.; Zlotnik, V. A.; Ong, J.

2013-12-01

73

Field investigation of evaporation from freshwater tailings  

SciTech Connect

Safe and economical storage of tailings is now a major consideration in the operation of many mining operations. Tailings in slurried form, particularly if they have a significant clay content, can take a very long time to consolidate under the action of self-weight consolidation alone. However, if the operation is located in an area of high potential evaporation, this can be used to accelerate the rate of tailings densification. This paper presents a study of the evaporation behavior of a clayey tailings slurry deposited into an evaporation pond in the southwest of Western Australia. Over a six-month period, the rate of evaporation from the tailings surface was monitored using the Bowen Ratio method and the microlysimeter method. This was compared with the evaporation from a Class A pan located nearby. The tailings underwent very significant cracking as drying proceeded, and it was found that these cracks had a significant influence on the overall rate of evaporation once the top surface of the deposit started to desaturate. A large strain consolidation model was used to model the behavior, and the algorithm used in this model to include the effects of evaporation is shown to provide a reasonable prediction of the observed evaporation behavior.

Fujiyasu, Yoshimasa; Fahey, M.; Newson, T.

2000-06-01

74

Stable isotopes in pedogenic calcite: Can the positive linear covariant trends be used to quantify paleo-evaporation rates?  

NASA Astrophysics Data System (ADS)

Paleoclimatological models suggest enhanced evaporation rates in subtropical regions during greenhouse- world conditions. Laboratory evaporation experiments show that calcites precipitated from variably saturated solutions yield a positive linear covariant trend (PLCT) in ?18O vs ?13C values. This investigation experimentally quantifies calcite PLCT so that ?13C of subtropical paleosol calcretes may be used as a regional proxy of paleo-evaporation rates. A series of powdered CaCO3 samples with ?18O and ?13C values of -19.6 and -37.2 VPDB respectively were dissolved in deionized water in a pressure sealed container; it also contained separate vials of calcite reacted with HCl to generate a range of pCO2 environments, thus simulating a soil atmosphere. The variable pCO2 conditions simulate expected soil atmosphere pCO2 conditions in a calcrete horizon during alternative phases of calcite dissolution and precipitation. After 24 hrs, the solutions were placed in an open beaker in an incubator at 36C and allowed to evaporate. Aliquots of 100 ?L were removed at 24 hr intervals and the time of calcite crystal nucleation was also noted. Water analyses yielded ?18O enrichments ranging from an initial value of -4.8 VSMOW to a range of +10.0 to +14.8 VSMOW after an evaporation period of 75 hrs. The most enriched water values were attained from the solutions formed under lower pCO2 conditions (more enriched calcite ?18O, ?13C). The array of calcite ?18O vs ?13C values fall upon a PLCT that projects from a theoretical meteoric calcite line (MCL) calculated from the incubation temperature and deionized water ?18O and ?13C values. The precipitated calcite ?18O values range from the MCL value of -8.8 VPDB to +0.5 VPDB. The higher pCO2 waters precipitated calcite very early during evaporation, and thus the ?18O and ?13C calcite values are slightly enriched relative to the theoretical MCL. The lower pCO2 conditions precipitated calcite late in the evaporation of the fluids, and thus yield more enriched calcite ?18O and ?13C values. Ongoing experiments under warmer and cooler evaporation temperatures will aid in the development of a quantitative model for paleo-evaporation rates from paleosol calcretes.

Grcke, D.; Ufnar, D.; Beddows, P. A.

2007-12-01

75

Evaporation Rates of Chemical Warfare Agents using 5 CM Wind Tunnels. 5. VX From Sand and Concrete.  

National Technical Information Service (NTIS)

The evaporation of VX from sand and concrete was studied as a function of temperature, drop size and air flow rate. One sand substrate and five carefully controlled concrete compositions were used in this study. For VX on sand and concrete, an equation wa...

C. A. Brevett C. V. Giannaras J. J. Pence J. P. Myers R. G. Nickol

2010-01-01

76

Effects of viscosity, surface tension, and evaporation rate of solvent on dry colloidal structures: A lattice Boltzmann study  

NASA Astrophysics Data System (ADS)

Understanding the mechanisms of how colloidal solution properties and drying processes result in dry colloidal structures is essential for industrial applications such as paint, ceramics, and electrodes. In this study, we develop a computational method to simulate the drying process of colloidal suspensions containing solid particles and polymers. The method consists of a solvent evaporation model, a fluid particle dynamics method, and a two-phase lattice Boltzmann method. We determine that a high-viscosity solvent, small surface tension, and a high evaporation rate of the solvent lead to a structure with dispersed particles and interconnected pores. When these conditions are not present, the particles agglomerate and the pores are disconnected.

Munekata, Toshihisa; Suzuki, Takahisa; Yamakawa, Shunsuke; Asahi, Ryoji

2013-11-01

77

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

78

A New Approach to Measure Contact Angle and Evaporation Rate with Flow Visualization in a Sessile Drop  

NASA Technical Reports Server (NTRS)

The contact angle and the spreading process of sessile droplet are very crucial in many technological processes, such as painting and coating, material processing, film-cooling applications, lubrication, and boiling. Additionally, as it is well known that the surface free energy of polymers cannot be directly, measured for their elastic and viscous restraints. The measurements of liquid contact angle on the polymer surfaces become extremely important to evaluate the surface free energy of polymers through indirect methods linked with the contact angle data. Due to the occurrence of liquid evaporation is inevitable, the effects of evaporation on the contact angle and the spreading become very important for more complete understanding of these processes. It is of interest to note that evaporation can induce Marangoni-Benard convection in sessile drops. However, the impacts of the inside convection on the wetting and spreading processes are not clear. The experimental methods used by previous investigators cannot simultaneously measure the spreading process and visualize the convection inside. Based on the laser shadowgraphic system used by the present author, a very simple optical procedure has been developed to measure the contact angle, the spreading speed, the evaporation rate, and to visualize inside convection of a sessile drop simultaneously. Two CCD cameras were used to synchronously record the real-time diameter of the sessile drop, which is essential for determination of both spreading speed and evaporation rate, and the shadowgraphic image magnified by the sessile drop acting as a thin plano-convex lens. From the shadowgraph, the inside convection of the drop can be observed if any and the image outer diameter, which linked to the drop profile, can be measured. Simple equations have been derived to calculate the drop profile, including the instantaneous contact angle, height, and volume of the sessile drop, as well as the evaporation rate. The influence of the inside convection on the wetting and spreading processes can be figured out through comparison of the drop profiles with and without inside convection when the sessile drop is placed at different evaporation conditions.

Zhang, Nengli; Chao, David F.

1999-01-01

79

A Wind Tunnel Investigation of the Rate of Evaporation of Small Water Drops Falling at Terminal Velocity in Air  

Microsoft Academic Search

An experimental study of the effect of ventilation on the rate of evaporation of small water drops falling at terminal velocity in air has been carried out in a wind tunnel where water drops could he suspended freely in the tunnel airstream. For Reynolds numbers NRe2 it was found that the Sherwood number NSh was linearly related to NRe1\\/2NI, in

K. V. Beard; H. R. Pruppacher

1971-01-01

80

Effects of viscosity, surface tension, and evaporation rate of solvent on dry colloidal structures: a lattice Boltzmann study.  

PubMed

Understanding the mechanisms of how colloidal solution properties and drying processes result in dry colloidal structures is essential for industrial applications such as paint, ceramics, and electrodes. In this study, we develop a computational method to simulate the drying process of colloidal suspensions containing solid particles and polymers. The method consists of a solvent evaporation model, a fluid particle dynamics method, and a two-phase lattice Boltzmann method. We determine that a high-viscosity solvent, small surface tension, and a high evaporation rate of the solvent lead to a structure with dispersed particles and interconnected pores. When these conditions are not present, the particles agglomerate and the pores are disconnected. PMID:24329271

Munekata, Toshihisa; Suzuki, Takahisa; Yamakawa, Shunsuke; Asahi, Ryoji

2013-11-01

81

Makgadikgadi Salt Pan, Botswana, Africa  

NASA Technical Reports Server (NTRS)

The Makgadikgadi Salt Pan of Botswana, an ancient lake bed, (19.0S, 26.0E) is one of the largest features in Botswana visible from orbit. Any water that spills out of the Okavango Swamplands flows into the Makagadikgadi where it evaporates. An ancient beach line can be seen as a smooth line around the west side of the pan and to the south, the Orapa diamond mine is seen as a small rectangle. Far to the east, can be seen the Great Dike of Zimbabwe.

1992-01-01

82

Measuring forest evaporation and transpiration rates with fibre optic temperature sensing  

NASA Astrophysics Data System (ADS)

Evaporation is one of the most important fluxes of the water balance as it accounts for 55-80% of the precipitation. However, measuring evaporation remains difficult and requires sophisticated and expensive equipment. In this paper we propose a new measuring technique based on the existing Bowen ratio method. With a fibre optic cable a temperature and a vapour pressure profile can be measured by the principle of a psychrometer and combined with the net radiation (and ground heat flux) the latent heat can be calculated. Compared to the conventional Bowen ratio method the advantages of this method is that the profiles are measured with a single sensor (resulting in a smaller error), and contain more measuring points in the vertical and therefore give more insight into the developed profiles. The method also allows to measure through a forest canopy. Applying the Bowen ratio above and below the canopy an estimation of the transpiration flux can be obtained. As a first test, we compared in a pine forest in The Netherlands (Loobos) the transpiration estimates of the fibre optic cable with sapflow measurements, and eddy covariance measurements above and below the canopy. The experiment was carried out on three days in September 2013 and the preliminary results show reasonable correlation with the eddy covariance estimates, but not with the sapflow observations. To explain the differences further investigation is needed and a longer measuring period is required.

Coenders-Gerrits, Miriam; Luxemburg, Wim; Hessels, Tim; de Kloe, Arjan; Elbers, Jan

2014-05-01

83

Evaporation in the Atacama Desert: An empirical study of spatio-temporal variations and their causes  

NASA Astrophysics Data System (ADS)

SummaryThe Atacama Desert is hyper-arid, and areas where adequate moisture exists for evaporation are spatially highly restricted. Nevertheless, water resources exist and their evaluation requires knowledge of this elusive but important component of the hydrological cycle. Evaporation may occur in four typical areas: rivers and associated riparian zones, localized springs, large playas and extensive areas of bare soil after infrequent precipitation events. Transpiration is locally possible where moisture is sufficiently close to the surface to allow phreatophytes or scarce grass cover to grow, but virtually no information is available for quantification. Pan evaporation data from 11 stations for the period 1977-1991 is analyzed and complemented by analysis of an evaporation study conducted in the Salar de Atacama during 1987/1988. The results show that pan evaporation, and hence maximum potential evaporation may be considered largely a function of maximum temperature and elevation as well as density of the evaporating fluid. Actual evaporation is limited by available moisture and diminishes rapidly as the level of soil moisture saturation drops below the soil surface, extinguishing at ca. 2 m depth. Evaporation is greatest during the summer, but at higher elevations convective cloudiness develops during January and February reducing evaporating rates at a time when significant precipitation may occur. Inter-annual variations in pan evaporation are considerable and weakly correlated with ENSO, but variations in actual evaporation are damped by comparison. Regression equations are developed which have widespread applicability and may be used to estimate evaporation in areas where no site-specific data exists.

Houston, John

2006-11-01

84

Flow Visualization in Evaporating Liquid Drops and Measurement of Dynamic Contact Angles and Spreading Rate  

NASA Technical Reports Server (NTRS)

A new hybrid optical system, consisting of reflection-refracted shadowgraphy and top-view photography, is used to visualize flow phenomena and simultaneously measure the spreading and instant dynamic contact angle in a volatile-liquid drop on a nontransparent substrate. Thermocapillary convection in the drop, induced by evaporation, and the drop real-time profile data are synchronously recorded by video recording systems. Experimental results obtained from this unique technique clearly reveal that thermocapillary convection strongly affects the spreading process and the characteristics of dynamic contact angle of the drop. Comprehensive information of a sessile drop, including the local contact angle along the periphery, the instability of the three-phase contact line, and the deformation of the drop shape is obtained and analyzed.

Zhang, Neng-Li; Chao, David F.

2001-01-01

85

Control of Leaf Expansion Rate of Droughted Maize Plants under Fluctuating Evaporative Demand (A Superposition of Hydraulic and Chemical Messages?).  

PubMed Central

We have analyzed the possibility that chemical signaling does not entirely account for the effect of water deficit on the maize (Zea mays L.) leaf elongation rate (LER) under high evaporative demand. We followed time courses of LER (0.2-h interval) and spatial distribution of elongation rate in leaves of either water-deficient or abscisic acid (ABA)-fed plants subjected to varying transpiration rates in the field, in the greenhouse, and in the growth chamber. At low transpiration rates the effect of the soil water status on LER was related to the concentration of ABA in the xylem sap and could be mimicked by feeding artificial ABA. Transpiring plants experienced a further reduction in LER, directly linked to the transpiration rate or leaf water status. Leaf zones located at more than 20 mm from the ligule stopped expanding during the day and renewed expansion during the night. Neither ABA concentration in the xylem sap, which did not appreciably vary during the day, nor ABA flux into shoots could account for the effect of evaporative demand. In particular, maximum LER was observed simultaneously with a minimum ABA flux in the droughted plants, but with a maximum ABA flux in ABA-fed plants. All data were interpreted as the superposition of two additive effects: the first involved ABA signaling and was observed during the night and in ABA-fed plants, and the second involved the transpiration rate and was observed even in well-watered plants. We suggest that a hydraulic signal is the most likely candidate for this second effect.

Salah, HBH.; Tardieu, F.

1997-01-01

86

PANs in the Atmosphere.  

National Technical Information Service (NTIS)

The types of peroxyacetyl nitrates (PANs) and peroxybenzyl nitrates (PBzNs) present or possibly present in the ambient atmosphere are discussed. Biological activities of the PANs and PBzNs are briefly considered. The concentration and composition of PANs ...

A. P. Altshuller

1993-01-01

87

Analysis of rate-limiting processes in soil evaporation with implications for soil resistance models  

Microsoft Academic Search

Numerical integrations of coupled equations of moisture, vapor and heat diffusion in soil are analyzed to explore the relative roles of vapor and liquid fluxes in rate-limiting the transfer of water to the soilatmosphere interface. Approximate analytical integrations of a simpler isothermal system are then introduced to explore the interactions of vapor and liquid transport. Although vapor diffusion dominates total

Thambirajah Saravanapavan; Guido D. Salvucci

2000-01-01

88

Global distribution of moisture, evaporation-precipitation, and diabatic heating rates  

NASA Technical Reports Server (NTRS)

Global archives were established for ECMWF 12-hour, multilevel analysis beginning 1 January 1985; day and night IR temperatures, and solar incoming and solar absorbed. Routines were written to access these data conveniently from NASA/MSFC MASSTOR facility for diagnostic analysis. Calculations of diabatic heating rates were performed from the ECMWF data using 4-day intervals. Calculations of precipitable water (W) from 1 May 1985 were carried out using the ECMWF data. Because a major operational change on 1 May 1985 had a significant impact on the moisture field, values prior to that date are incompatible with subsequent analyses.

Christy, John R.

1989-01-01

89

Evaluation of evaporation estimation methods for a covered reservoir in a semi-arid climate (south-eastern Spain)  

NASA Astrophysics Data System (ADS)

SummaryThe main purpose of this study was to evaluate different methods of evaporation estimation for covered water reservoirs. A reservoir equipped with a suspended cover was fully monitored to register the evaporation rate and microclimate below the cover. The datasets were used to evaluate the performance of commonly used evaporation methods, namely energy budget, mass-transfer, combination (Penman and FAO-56 Penman-Monteith) and floating class-A pan. The mass-transfer formula based on the Sherwood number proposed for free convection conditions, which were observed to prevail below the cover, supplied reasonably good estimates of covered reservoir evaporation and it is a good option from a practical point of view, with low input data requirements. Detailed input data and modifications in the calculation of energy fluxes are required to get good evaporation estimations of covered surfaces with the energy budget and FAO-56 Penman-Monteith methods. Besides, some of the standard meteorological input data (such as wind speed at 2 m height) cannot be registered below the cover. Penman equation presented a poor performance related to the overestimation of the advective component for free convection conditions. The pan evaporation was found to be substantially higher than the reservoir evaporation, due to the particular characteristics of the tank, that increased surface temperature and hence evaporation rate. A simplified empirical mass-transfer formula was also proposed to estimate evaporation of covered water bodies from the only knowledge of the surface-to-air mixing ratio gradient.

Gallego-Elvira, B.; Baille, A.; Martn-Gorriz, B.; Maestre-Valero, J. F.; Martnez-Alvarez, V.

2012-08-01

90

Repeatability and individual correlates of basal metabolic rate and total evaporative water loss in birds: A case study in European stonechats  

Microsoft Academic Search

Basal metabolic rate (BMR) and total evaporative water loss (TEWL) are thought to have evolved in conjunction with life history traits and are often assumed to be characteristic features of an animal. Physiological traits can show large intraindividual variation at short and long timescales, yet natural selection can only act on a trait if it is a characteristic feature of

Maaike A. Versteegh; Barbara Helm; Niels J. Dingemanse; B. Irene Tieleman

2008-01-01

91

Evaporative Cooling Membrane Device  

NASA Technical Reports Server (NTRS)

An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

Lomax, Curtis (Inventor); Moskito, John (Inventor)

1999-01-01

92

PANS IN THE ATMOSPHERE  

EPA Science Inventory

The types of PANs and PBzN's present or possibly present in the ambient atmosphere are discussed. iological activities of the PAN's and PBzN's are briefly considered. he concentration and composition of PANs in the atmosphere are discussed and calculations made of the production ...

93

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

94

Evaporation Investigation  

NSDL National Science Digital Library

This is a hands-on lab activity about evaporation. Learners will conduct experiments to observe the process of evaporation. They will then describe the process of evaporation, and the general water cycle, through discussion and pictures. Background information, common preconceptions, a glossary and more is included. This activity is part of the Aquarius Hands-on Laboratory Activities.

95

A Comparison of Methods for Estimating Open-Water Evaporation in Small Wetlands  

Microsoft Academic Search

We compared evaporation measurements from a floating pan, land pan, chamber, and the Priestley-Taylor (PT) equation. Floating\\u000a pan, land pan, and meteorological data were collected from June 6 to July 21, 2005, at a small wetland in the Canadian River\\u000a alluvium in central Oklahoma, USA. Evaporation measured with the floating pan compared favorably to 12h chamber measurements.\\u000a Differences between chamber

Jason R. Masoner; David I. Stannard

2010-01-01

96

Development of Statistical Typhoon Intensity Prediction: Application to Satellite-Observed Surface Evaporation and Rain Rate (STIPER)  

NASA Astrophysics Data System (ADS)

A statistical-dynamical model has been used for operational guidance for tropical cyclone (TC) intensity prediction. In this study, several multiple linear regression models and neural network (NN) models are developed for the intensity prediction of western North Pacific TCs at 24-, 48-, and 72-h intervals. The multiple linear regression models include a model of climatology and persistence (CLIPER), a model based on the Statistical Typhoon Intensity Prediction System (STIPS), which serves as the base regression model (BASE), and a model of STIPS with additional satellite estimates of surface evaporation (SLHF) and innercore rain rate (IRR, STIPER model). A revised equation for the TC maximum potential intensity is derived using Tropical Rainfall Measuring Mission Microwave Imager optimally interpolated sea surface temperature data, which have higher temporal and spatial resolutions. Analyses of the resulting models show the marginal improvement of STIPER over BASE. However, IRR and SLHF are found to be significant predictors in the predictor pool. Neural network models using the same predictors as STIPER show reductions of the mean absolute errors of 7%, 11%, and 16% relative to STIPER for 24-, 48-, and 72-h forecasts, respectively. The largest improvement is found for the intensity forecasts of the rapidly intensifying and rapidly decaying TCs. (top) The 24-h BASE, STIPER, and NN24 model mean absolute errors (MAEs) stratified by best-track initial intensity (MWS0) in 5-kt bins and (bottom) 24-h intensity change (DELV) in 5-kt bins for all nine verification years. Lower values of MAEs represent better forecasts. Dashed dotted lines represent the numbers of valid observations within a particular bin.

Gao, S.; Chiu, L.

2012-12-01

97

Pan Balance-Numbers  

NSDL National Science Digital Library

This Java tool is used to strengthen student understanding of equality and computation of numerical expressions. The applet also helps students understand that equality is a relationship, not an operation. After entering an expression in both the red and blue pan, the pans will move up and down depending on which expression is greater. When the expressions are equivalent, the pans will balance and the full equation will be entered into the Balanced Equations table. Instructions and exploration directions and questions are included.

2011-01-01

98

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 Gaud; Gabriel Abadal; Jaume Verd; Jordi Teva; Francesc Prez-Murano; Eduardo Figueras Costa; Josep Montserrat; Arantxa Uranga; Jaume Esteve; Nria Barniol

2007-01-01

99

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

100

Quantitative microbiological analysis of bacterial community shifts in a high-rate anaerobic bioreactor treating sulfite evaporator condensate.  

PubMed

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 x 10 to 7 x 10 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 x 10 to 7.5 x 10 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 x 10 to 2.6 x 10 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 x 10 to 5.8 x 10 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. PMID:16348253

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

1990-08-01

101

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

Evaporation is the consequence of slow plasma heating near the tops of streamers where the plasma is only weakly contained by the magnetic field. The form it takes is the slow opening of field lines at the top of the streamer and transient formation of new solar wind. It was discovered in polytropic model calculations, where due to the absence of other energy loss mechanisms in magnetostatic streamers, its ultimate endpoint is the complete evaporation of the streamer. This takes, for plausible heating rates, weeks to months in these models. Of course streamers do not behave this way, for more than one reason. One is that there are losses due to thermal conduction to the base of the streamer and radiation from the transition region. Another is that streamer heating must have a characteristic time constant and depend on the ambient physical conditions. We use our global Magnetohydrodynamics (MHD) model with thermal conduction to examine a few examples of the effect of changing the heating scale height and of making ad hoc choices for how the heating depends on ambient conditions. At the same time, we apply and extend the analytic model of streamers, which showed that streamers will be unable to contain plasma for temperatures near the cusp greater than about 2xl0(exp 6) K. Slow solar wind is observed to come from streamers through transient releases. A scenario for this that is consistent with the above physical process is that heating increases the near-cusp temperature until field lines there are forced open. The subsequent evacuation of the flux tubes by the newly forming slow wind decreases the temperature and heating until the flux tubes are able to reclose. Then, over a longer time scale, heating begins to again refill the flux tubes with plasma and increase the temperature until the cycle repeats itself. The calculations we report here are first steps towards quantitative evaluation of this scenario.

Suess, Steven T.; Wang, A. H.; Wu, Shi T.; Nerney, S.

1998-01-01

102

Loving Peter Pan.  

ERIC Educational Resources Information Center

Explores the story of "Peter Pan." Considers its creation, its role on the stage, and its impact on society. Considers how "Peter Pan" is about the inability to have make-believe and the true stick together: it dramatizes an artistic failure, the failure to make the vision of the play successful. (SG)

Kinkaid, James R.

2003-01-01

103

Evaporation estimates from the Dead Sea and their implications on its water balance  

NASA Astrophysics Data System (ADS)

The Dead Sea (DS) is a terminal hypersaline water body situated in the deepest part of the Jordan Valley. There is a growing interest in linking the DS to the open seas due to severe water shortages in the area and the serious geological and environmental hazards to its vicinity caused by the rapid level drop of the DS. A key issue in linking the DS with the open seas would be an accurate determination of evaporation rates. There exist large uncertainties of evaporation estimates from the DS due to the complex feedback mechanisms between meteorological forcings and thermophysical properties of hypersaline solutions. Numerous methods have been used to estimate current and historical (pre-1960) evaporation rates, with estimates differing by 100%. Evaporation from the DS is usually deduced indirectly using energy, water balance, or pan methods with uncertainty in many parameters. Accumulated errors resulting from these uncertainties are usually pooled into the estimates of evaporation rates. In this paper, a physically based method with minimum empirical parameters is used to evaluate historical and current evaporation estimates from the DS. The more likely figures for historical and current evaporation rates from the DS were 1,500-1,600 and 1,200-1,250 mm per annum, respectively. Results obtained are congruent with field observations and with more elaborate procedures.

Oroud, Ibrahim M.

2011-12-01

104

Vacuum Evaporation of Pure Metals  

NASA Astrophysics Data System (ADS)

Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision length from the evaporating surface, the Hertz-Knudsen equation applies. For a case where the condensing surface is not close to the evaporating surface, a pressure criterion for intensive evaporation is introduced, called the effective vacuum pressure, p eff. It is a fraction of the vapor pressure of the pure metal. The vacuum evaporation rate should not be affected by pressure changes below p eff, so that in lower pressures below p eff, the evaporation flux is constant and equal to a fraction of the maximum evaporation flux given by Hertz-Knudsen equation as 0.844 dot{n}_{Max } . Experimental data on the evaporation of liquid and solid metals are included.

Safarian, Jafar; Engh, Thorvald A.

2013-02-01

105

Evaporation from soybeans  

NASA Astrophysics Data System (ADS)

During the 1974 growing season, a micrometeorological measurement program was conducted at Simcoe, Ontario, Canada to study atmospheric and surface control on hourly and daytime evaporation from soybeans. For days when leaf area index exceeded unity, daytime evaporation varied linearly with volumetric soil moisture content when the latter was less than 0.12. At larger volumetric soil moisture contents, evaporation proceeded at a potential rate. The data confirm the usefulness of the Priestley and Taylor model with a proportionality constant of 1.26.

Bailey, W. G.; Davies, J. A.

1981-06-01

106

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

107

Determining the virtual surface in the thermal evaporation process of magnesium fluoride from a tungsten boat for different deposition rates, to be used in precision optical components  

NASA Astrophysics Data System (ADS)

Vacuum thermal evaporation has, for some time now, been the principal method for the deposition of thin films, given, among other aspects, its simplicity, flexibility, and relatively low cost. Therefore, the development of models attempting to predict the deposition patterns of given thin film materials in different locations of a vacuum evaporation chamber are arguably important. With this in mind, we have designed one of such models for the thermal evaporation process of magnesium fluoride (MgF2), a common material used in optical thin films, originating from a tungsten boat source. For this we took several deposition samples in glass slide substrates at different locations in the vacuum chamber, considering as independent variables the mean deposition rate, and the axial and vertical distances of the source to the substrate. After a careful analysis by matrix method from the spectral transmittance data of the samples, while providing as output data the spectral transmittance, as well as the physical thickness of the films, both as functions of the aforementioned variables, the virtual surface of the source was determined.

Tejada Esteves, A.; Glvez de la Puente, G.

2013-11-01

108

Pan Balance - Numbers  

NSDL National Science Digital Library

Use this tool to find numerical expressions that are equivalent to one another. If equivalent expressions are placed in the blue and red pans, the scale will balance and the equation will show in the table next to the balance.

Mathematics, National C.

2009-07-22

109

Effect of argon gas flow rate on properties of film electrodes prepared by thermal vacuum evaporation from synthesized Cu2SnSe3 source  

NASA Astrophysics Data System (ADS)

This work describes a new technique to enhance photoresponse of metal chalcogenide-based semiconductor film electrodes deposited by thermal vacuum evaporation under argon gas flow from synthesized Cu2SnSe3 sources. SnSe formation with Cu-doped was obtained under higher argon gas flow rate (VA = 25 cm3/min). Higher value of photoresponse was observed for films deposited under VA = 25 cm3/min which was 9.1%. This finding indicates that Cu atoms inside the SnSe film were important to increase carrier concentrations that promote higher photoresponse.

Sabli, Nordin; Talib, Zainal Abidin; Yunus, Wan Mahmood Mat; Zainal, Zulkarnain; Hilal, Hikmat S.; Fujii, Masatoshi

2014-03-01

110

A Scanning Electron and Atomic Force Microscopy Study of the Surface Morphology and Composition of CsI Films as Affected by Evaporation Rate and Humid-Air Exposure  

Microsoft Academic Search

Evaporation rate and subsequent exposure to humid air affect the surface morphology and composition of cesium iodide (CsI) films and, in turn, their photoemissive efficiency when used as photocathodes. The surface morphology and elemental composition of 300-nm-thick CsI films grown at two different rates (1 nm\\/s and 0.04 nm\\/s), both freshly evaporated and after 24-h exposure to humid air were

Giorgio S. Senesi; Mariangela A. Nitti; Antonio Valentini

2005-01-01

111

Pan Balance-Expressions  

NSDL National Science Digital Library

This interactive pan balance allows students to enter numeric or algebraic expressions and investigate the important concept of equivalence as well as practice arithmetic and algebraic skills. Users place an expression in each of the red and blue pans. These expressions may or may not include the variable x. If the expression is algebraic, a value for x is entered or adjusted by moving the slider. As the value of x changes, the results will be weighed and graphed. Instructions and exploration directions and questions are included.

2011-01-01

112

Electrochemical treatment of evaporated residue of soak liquor generated from leather industry.  

PubMed

The organic and suspended solids present in soak liquor, generated from leather industry, demands treatment. The soak liquor is being segregated and evaporated in solar evaporation pans/multiple effect evaporator due to non availability of viable technology for its treatment. The residue left behind in the pans/evaporator does not carry any reuse value and also faces disposal threat due to the presence of high concentration of sodium chloride, organic and bacterial impurities. In the present investigation, the aqueous evaporated residue of soak liquor (ERSL) was treated by electrochemical oxidation. Graphite/graphite and SS304/graphite systems were used in electrochemical oxidation of organics in ERSL. Among these, graphite/graphite system was found to be effective over SS304/graphite system. Hence, the optimised conditions for the electrochemical oxidation of organics in ERSL using graphite/graphite system was evaluated by response surface methodology (RSM). The mass transport coefficient (km) was calculated based on pseudo-first order rate kinetics for both the electrode systems (graphite/graphite and SS304/graphite). The thermodynamic properties illustrated the electrochemical oxidation was exothermic and non-spontaneous in nature. The calculated specific energy consumption at the optimum current density of 50 mA cm(-2) was 0.41 kWh m(-3) for the removal of COD and 2.57 kWh m(-3) for the removal of TKN. PMID:23770619

Boopathy, R; Sekaran, G

2013-09-15

113

The Pan Zhichang Incident  

ERIC Educational Resources Information Center

This article examines why Pan Zhichang, a well-known professor and Ph.D. candidate supervisor at Nanjing University, has repeatedly been accused of plagiarism. It may not be difficult to check whether he has committed plagiarism, but seeking the deeper social and systemic reasons for a person's repeated "negligence" is indeed a thought-provoking

Yuchen, Zhu

2007-01-01

114

PAN Pesticide Database  

NSDL National Science Digital Library

The Pesticide Action Network (PAN) Pesticide Database is your one-stop location for toxicity and regulatory information for pesticides. This is a comprehensive search enabled database of pesticide chemicals and also trade names. An easy to navigate sidebar takes you through toxicity, uses, registration, company, and distributor. Other links take you to less toxic alternatives, and pesticide tutorial and references.

0002-11-30

115

Pan Balance - Shapes  

NSDL National Science Digital Library

This resource provides a virtual manipulative pan balance to explore and practice equality with geometric shapes. Each shape is assigned a certain weight. The pictorial representation is entered in a table and the items on each side of the balance can be represented by an algebraic expression.

Mathematics, Illuminations N.

2009-03-04

116

Evaporative Cooler  

NSDL National Science Digital Library

Explore the concept of evaporative cooling through a hands-on experiment. Use a wet cloth and fan to model an air-conditioner and use temperature and relative humidity sensors to collect data. Then digitally plot the data using graphs in the activity. In an optional extension, make your own modifications to improve the cooler's efficiency.

Consortium, The C.

2011-12-12

117

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

118

The Analysis of 6LowPAN Technology  

Microsoft Academic Search

IPv6 over IEEE802.15.4 (a.k.a. 6LowPAN), has become the standard for low-rate wireless personal area networks (LR-WPAN). IPv6 is taken as an interconnection scheme for IEEE802.15.4 equipments at network layer, 6LowPAN technology has attracted extensive attention. This paper introduced IEEE802.15.4 standard and 6LowPAN technology, discussed 6LowPAN's advantages, analyzed its key technologies, and the applications of 6LowPAN were explored.

Xin Ma; Wei Luo

2008-01-01

119

Spatial distributions of expansion rate, cell division rate and cell size in maize leaves: a synthesis of the effects of soil water status, evaporative demand and temperature  

Microsoft Academic Search

extent. Conversely, cell size of epidermis and mesophyll were reduced by water deficit in mature The spatial distributions of leaf expansion rate, cell parts of the leaf. division rate and cell size was examined under con-

Francois Tardieu; Matthieu Reymond; Philippe Hamard; Christine Granier; Bertrand Muller

2000-01-01

120

Thermal evaporation-induced anhydrous synthesis of Fe3O4-graphene composite with enhanced rate performance and cyclic stability for lithium ion batteries.  

PubMed

We present a high-yield and low cost thermal evaporation-induced anhydrous strategy to prepare hybrid materials of Fe3O4 nanoparticles and graphene as an advanced anode for high-performance lithium ion batteries. The ~10-20 nm Fe3O4 nanoparticles are densely anchored on conducting graphene sheets and act as spacers to keep the adjacent sheets separated. The Fe3O4-graphene composite displays a superior battery performance with high retained capacity of 868 mA h g(-1) up to 100 cycles at a current density of 200 mA g(-1), and 539 mA h g(-1) up to 200 cycles when cycling at 1000 mA g(-1), high Coulombic efficiency (above 99% after 200 cycles), good rate capability, and excellent cyclic stability. The simple approach offers a promising route to prepare anode materials for practical fabrication of lithium ion batteries. PMID:23558566

Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Yang, Qingdan; Li, Yang Yang; Zapien, Juan Antonio

2013-05-21

121

Analysis of energy use in tomato evaporation  

SciTech Connect

Field performance data for four tomato product evaporators are presented and analyzed. Steam and feed flow rates along with steam economies were measured and are compared to steady state theoretical evaporator models.

Rumsey, T.; Conant, T.

1980-01-01

122

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

Evaporation is the consequence of heating near the top of streamers in ideal Magnetohydrodynamics (MHD) models, where the plasma is weakly contained by the magnetic field. Heating causes slow opening of field lines and release of new solar wind. It was discovered in simulations and, due to the absence of loss mechanisms, the ultimate end point is the complete evaporation of the streamer. Of course streamers do not behave in this way because there are losses by thermal conduction and radiation. Physically, heating is also expected to depend on ambient conditions. We use our global MHD model with thermal conduction to examine the effect of changing the heating scale height. We also apply and extend an analytic model of streamers developed by Pneuman (1968) to show that steady streamers are unable to contain plasma for temperatures near the cusp greater than approximately 2 x 10(exp 6) K.

Suess, S. T.; Wang, A.-H.; Wu, S. T.; Nerney, S. F.

1998-01-01

123

Skeletal development in Pan paniscus with comparisons to Pan troglodytes.  

PubMed

Fusion of skeletal elements provides markers for timing of growth and is one component of a chimpanzee's physical development. Epiphyseal closure defines bone growth and signals a mature skeleton. Most of what we know about timing of development in chimpanzees derives from dental studies on Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a wild range restricted to central Africa. Here, we report on the timing of skeletal fusion for female captive P. paniscus (n = 5) whose known ages range from 0.83 to age 11.68 years. Observations on the skeletons were made after the individuals were dissected and bones cleaned. Comparisons with 10 female captive P. troglodytes confirm a generally uniform pattern in the sequence of skeletal fusion in the two captive species. We also compared the P. paniscus to a sample of three unknown-aged female wild P. paniscus, and 10 female wild P. troglodytes of known age from the Ta National Park, Cte d'Ivoire. The sequence of teeth emergence to bone fusion is generally consistent between the two species, with slight variations in late juvenile and subadult stages. The direct-age comparisons show that skeletal growth in captive P. paniscus is accelerated compared with both captive and wild P. troglodytes populations. The skeletal data combined with dental stages have implications for estimating the life stage of immature skeletal materials of wild P. paniscus and for more broadly comparing the skeletal growth rates among captive and wild chimpanzees (Pan), Homo sapiens, and fossil hominins. PMID:22331605

Bolter, Debra R; Zihlman, Adrienne L

2012-04-01

124

A Scanning Electron and Atomic Force Microscopy Study of the Surface Morphology and Composition of CsI Films as Affected by Evaporation Rate and Humid-Air Exposure  

NASA Astrophysics Data System (ADS)

Evaporation rate and subsequent exposure to humid air affect the surface morphology and composition of cesium iodide (CsI) films and, in turn, their photoemissive efficiency when used as photocathodes. The surface morphology and elemental composition of 300-nm-thick CsI films grown at two different rates (1 nm/s and 0.04 nm/s), both freshly evaporated and after 24-h exposure to humid air were investigated by means of atomic force microscopy and scanning electron microscopy/electron diffraction spectroscopy. The CsI film freshly evaporated at a slow rate exhibited a granular surface presenting circular holes or craters where the CsI material was moved from the center to the boundaries. After 24-h exposure to humid air, this film coalesced in large grain showing a marked increase of surface roughness. Conversely, the CsI film grown at a fast rate mostly retained its original surface uniformity and homogeneity with no presence of holes and craters after 24-h exposure to humid air. Further, surface roughness and average peak height decreased, but the surface coalesced in large grains spaced by small fractures where the CsI coverage was almost lost. In conclusion, the films grown at a fast evaporation rate were affected by 24-h exposure to humid air less than those grown at a slow rate, and are thus expected to possess a greater long-term stability.

Senesi, Giorgio S.; Nitti, Mariangela A.; Valentini, Antonio

2005-04-01

125

A scanning electron and atomic force microscopy study of the surface morphology and composition of CsI films as affected by evaporation rate and humid-air exposure.  

PubMed

Evaporation rate and subsequent exposure to humid air affect the surface morphology and composition of cesium iodide (CsI) films and, in turn, their photoemissive efficiency when used as photocathodes. The surface morphology and elemental composition of 300-nm-thick CsI films grown at two different rates (1 nm/s and 0.04 nm/s), both freshly evaporated and after 24-h exposure to humid air were investigated by means of atomic force microscopy and scanning electron microscopy/electron diffraction spectroscopy. The CsI film freshly evaporated at a slow rate exhibited a granular surface presenting circular holes or craters where the CsI material was moved from the center to the boundaries. After 24-h exposure to humid air, this film coalesced in large grain showing a marked increase of surface roughness. Conversely, the CsI film grown at a fast rate mostly retained its original surface uniformity and homogeneity with no presence of holes and craters after 24-h exposure to humid air. Further, surface roughness and average peak height decreased, but the surface coalesced in large grains spaced by small fractures where the CsI coverage was almost lost. In conclusion, the films grown at a fast evaporation rate were affected by 24-h exposure to humid air less than those grown at a slow rate, and are thus expected to possess a greater long-term stability. PMID:15817141

Senesi, Giorgio S; Nitti, Mariangela A; Valentini, Antonio

2005-04-01

126

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

127

High-rate and low-temperature growth of ZnO:Ga thin films by steered cathodic arc plasma evaporation  

NASA Astrophysics Data System (ADS)

Ga-doped ZnO (GZO) thin films with various thicknesses (120-520 nm) are deposited on the glass substrate at a high growth rate of 220 nm/min and a low temperature of 120 C by a steered cathodic arc plasma evaporation (steered CAPE). The growth mechanism, microstructure, residual stress, surface morphology, electrical and optical properties, chemical states, electron transport behaviors and thickness effect of the GZO films are investigated. The film stress is gradually relaxed from -0.516 GPa to -0.090 GPa with thickness increasing. Transmission electron microscopy (TEM) images show that the GZO microstructure consists of c-axis textured columnar grains accompanied by some embedded nanodroplets. The droplet size is significantly reduced when a high-melting-point (1975 C) GZO ceramic target is adopted. High-resolution TEM image shows the GZO crystallites nucleated directly onto the amorphous substrate. The electrical properties improve with increasing thickness. The lowest resistivity (4.72 10-4 ? cm) is achieved at the thickness of 520 nm, with a corresponding transmittance of 89% in the visible region. Temperature-dependent resistivity measurements show that metal-semiconductor transition temperature increases from 136 K to 225 K when decreasing the thickness, which is due to the increasing the localized states caused by the defects and chemisorbed oxygen in thinner film.

Liang, Chih-Hao; Wang, Wei-Lin; Hwang, Weng-Sing

2013-01-01

128

Evaporation of forsterite in H 2 gas  

Microsoft Academic Search

Kinetics of evaporation of forsterite in hydrogen gas was investigated by high temperature vacuum experiments in the pressure range plausible for the solar nebula. The evaporation rate at total pressure (Ptot) below 10?6 bar is nearly constant and is similar to that in vacuum, whereas the rate at 10?6 to 10?3 bar is dependent on Ptot. The evaporation rate, JexpFo,

Hiroko Nagahara; Kazuhito Ozawa

1996-01-01

129

Evaporation from open microchannel grooves.  

PubMed

The evaporation of water from open u-shaped microchannel grooves was investigated with particular emphasis on the roles of channel width and air flow conditions. Given the small dimensions of the microchannels, all measurements were conducted in a range where convection and diffusion are of equal importance and known correlations for the calculation of mass transfer coefficients cannot be applied. The evaporation rates were measured using a new optical method and a gravimetric method. Both measurement methods yielded mass transfer coefficients that are in agreement with each other. The observed relation between mass transfer coefficient, air velocity and channel width vastly differs from the predictions obtained from macroscopic structures. With respect to diagnostic devices we conclude that analyte concentration in an open microchannel groove strongly increases even within short times due to the evaporation process and we show that wider channels are more favourable in terms of minimizing the relative evaporation rate. PMID:24345870

Kachel, Sibylle; Zhou, Ying; Scharfer, Philip; Vran?i?, Christian; Petrich, Wolfgang; Schabel, Wilhelm

2014-02-21

130

Evaporation of extrasolar planets  

NASA Astrophysics Data System (ADS)

This article presents a review on the observations and theoretical modeling of the evaporation of extrasolar planets. The observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the ``hot-Jupiters'' are described. The early observations of the first discovered transiting extrasolar planet, HD209458b, allowed the discovery that this planet has an extended atmosphere of escaping hydrogen. Subsequent observations showed the presence of oxygen and carbon at very high altitude. These observations give unique constraints on the escape rate and mechanism in the atmosphere of hot-Jupiters. The most recent Lyman-alpha HST observations of HD189733b and MgII observations of Wasp-12b allow for the first time a comparison of the evaporation from different planets in different environments. Models to quantify the escape rate from the measured occultation depths, and an energy diagram to describe the evaporation state of hot-Jupiters are presented. Using this diagram, it is shown that few already known planets like GJ876d or CoRot-7b could be remnants of formerly giant planets.

Lecavelier Des Etangs, A.

2010-12-01

131

A Search for Fast Optical Transients in the Pan-STARRS1 Medium-Deep Survey: M-Dwarf Flares, Asteroids, Limits on Extragalactic Rates, and Implications for LSST  

NASA Astrophysics Data System (ADS)

We present a search for fast optical transients (? ~ 0.5 hr-1 day) using repeated observations of the Pan-STARRS1 Medium-Deep Survey (PS1/MDS) fields. Our search takes advantage of the consecutive g P1 r P1 observations (16.5 minutes in each filter), by requiring detections in both bands, with non-detections on preceding and subsequent nights. We identify 19 transients brighter than 22.5 AB mag (S/N >~ 10). Of these, 11 events exhibit quiescent counterparts in the deep PS1/MDS templates that we identify as M4-M9 dwarfs at d ? 0.2-1.2 kpc. The remaining eight transients lack quiescent counterparts, exhibit mild but significant astrometric shifts between the g P1 and r P1 images, colors of (g - r)P1 ? 0.5-0.8 mag, non-varying light curves, and locations near the ecliptic plane with solar elongations of about 130, which are all indicative of main-belt asteroids near the stationary point of their orbits. With identifications for all 19 transients, we place an upper limit of R FOT(? ~ 0.5 hr) <~ 0.12 deg-2 day-1 (95% confidence level) on the sky-projected rate of extragalactic fast transients at <~ 22.5 mag, a factor of 30-50 times lower than previous limits; the limit for a timescale of ~1 day is R FOT <~ 2.4 10-3 deg-2 day-1. To convert these sky-projected rates to volumetric rates, we explore the expected peak luminosities of fast optical transients powered by various mechanisms, and find that non-relativistic events are limited to M ? -10 to ? - 14 mag for a timescale of ~0.5 hr to ~1 day, while relativistic sources (e.g., gamma-ray bursts, magnetar-powered transients) can reach much larger luminosities. The resulting volumetric rates are <~ 13 Mpc-3 yr-1 (M ? -10 mag), <~ 0.05 Mpc-3 yr-1 (M ? -14 mag), and <~ 10-6 Mpc-3 yr-1 (M ? -24 mag), significantly above the nova, supernova, and gamma-ray burst rates, respectively, indicating that much larger surveys are required to provide meaningful constraints. Motivated by the results of our search, we discuss strategies for identifying fast optical transients in the Large Synoptic Survey Telescope main survey, and reach the optimistic conclusion that the veil of foreground contaminants can be lifted with the survey data, without the need for expensive follow-up observations.

Berger, E.; Leibler, C. N.; Chornock, R.; Rest, A.; Foley, R. J.; Soderberg, A. M.; Price, P. A.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Metcalfe, N.; Stubbs, C. W.; Tonry, J. L.

2013-12-01

132

PanSNPdb: the Pan-Asian SNP genotyping database.  

PubMed

The HUGO Pan-Asian SNP consortium conducted the largest survey to date of human genetic diversity among Asians by sampling 1,719 unrelated individuals among 71 populations from China, India, Indonesia, Japan, Malaysia, the Philippines, Singapore, South Korea, Taiwan, and Thailand. We have constructed a database (PanSNPdb), which contains these data and various new analyses of them. PanSNPdb is a research resource in the analysis of the population structure of Asian peoples, including linkage disequilibrium patterns, haplotype distributions, and copy number variations. Furthermore, PanSNPdb provides an interactive comparison with other SNP and CNV databases, including HapMap3, JSNP, dbSNP and DGV and thus provides a comprehensive resource of human genetic diversity. The information is accessible via a widely accepted graphical interface used in many genetic variation databases. Unrestricted access to PanSNPdb and any associated files is available at: http://www4a.biotec.or.th/PASNP. PMID:21731755

Ngamphiw, Chumpol; Assawamakin, Anunchai; Xu, Shuhua; Shaw, Philip J; Yang, Jin Ok; Ghang, Ho; Bhak, Jong; Liu, Edison; Tongsima, Sissades

2011-01-01

133

The Imager for Mars Pathfinder Insurance Pan  

NASA Technical Reports Server (NTRS)

The Imager for Mars Pathfinder (IMP) obtained a full panorama of the Sagan Memorial Station landing site on Sol 2, before the IMP mast was deployed. The images in this panorama were taken in 4 filters (including stereo) and losslessly compressed to provide a high-quality multispectral survey of the landing site even if the IMP mast did not successfully deploy; this data set was therefore called the Insurance Pan. It was completed late in the afternoon of Sol 2, just before the IMP mast was (successfully) deployed. The data were stored in memory and returned to Earth after it became clear that downlink rates were higher than expected. The Insurance Pan horizontal (azimuth) coverage is nearly complete, with gaps caused by pointing errors and data packet losses. Stereo data were acquired in the blue (445 nm) filter, as well as right-eye green (531 nm), orange (600 nm), and near-infrared (752 nm) data.

Herkenhoff, K. E.; Johnson, J. R.; Weller, L. A.

2003-01-01

134

An eye on small reservoirs: remote sensing of storage volumes, their use as remotely sensed runoff gauges, and evaporation losses  

NASA Astrophysics Data System (ADS)

Small reservoirs are important sources of water supply for the scattered rural population in semi-arid areas. Due to their small size, and their existence in large numbers, such reservoirs have not been studied much. Little is known about their storage volumes, their impact on their watershed's contribution to runoff downstream, and their evaporation losses are frequently stated to be prohibitive. Satellite remote sensing can be used to assess and monitor small reservoirs' storage volumes with regional area-volume equations. Radar remote sensing of small reservoirs was found suitable especially during the rainy season due to its capability to penetrate clouds, but is affected by wind and lack of vegetation context during the dry season. Reservoirs were extracted most often successfully with a quasi-manual classification approach, as stringent classification rules often failed under less than optimal conditions. Especially wind speeds above 2.6 m s-1 at the time of image acquisition were detrimental (Bragg scattering) to the extraction of reservoirs. Due to lower wind speeds, the use of night time acquisitions was more effective than the use of daytime images. With a time series of radar images, small reservoirs were used as remotely sensed runoff gauges, and to calibrate hydrological rainfall-runoff models. Eight small reservoirs in the Upper East Region of Ghana, and Togo, were monitored to calibrate modified Thornthwaite-Mather models, in which increasing precipitation leads to exponentially increasing contributing areas. Model results indicate that the reservoirs captured, on the average, 34% of the quick flow, and 15% of overall runoff from their watersheds. Reservoir evaporation losses were measured directly with a floating evaporation pan and were compared to evaporation rates determined from the reservoir's energy budget, and Penman's equation. The direct pan measurements were generally lower than the evaporation determined with the energy budget or Penman. Compared to land based potential evaporation, the reservoir evaporation was not excessive. Regional wind patterns influence evaporation dynamics from the reservoir. Northeast winds with a high saturation deficit lead to significant evaporation losses, while the evaporation losses under moister, more prevalent southwest winds were moderate.

Liebe, J. R.; van de Giesen, N.; Andreini, M. S.; Walter, M. T.; Steenhuis, T. S.

2009-04-01

135

Can the worldwide changes in evaporative demand be reconciled with changes expected due to global warming?  

Microsoft Academic Search

Evaporation pans are devices, often used by agricultural scientists and engineers to schedule irrigation. They are also widely used by ecologists who recognise the ratio of 'actual to potential' as being of fundamental significance. Because of the practical importance, many organisations, in many countries, maintain standardised networks of pan evaporimeters. Using those data, the scientific community now has a reasonably

M. L. Roderick; G. D. Farquhar

2007-01-01

136

Evaporation of petroleum products from contaminated soils  

Microsoft Academic Search

Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular

Seon-Hong Kang; Charles S. Oulman

1996-01-01

137

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2013 CFR

... 4 2013-10-01 2013-10-01 false Ash pans. 230.69 Section 230.69 Transportation...MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans § 230.69 Ash pans. Ash pans shall be securely supported from...

2013-10-01

138

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2010 CFR

... 4 2009-10-01 2009-10-01 false Ash pans. 230.69 Section 230.69 Transportation...MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans § 230.69 Ash pans. Ash pans shall be securely supported from...

2009-10-01

139

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2010 CFR

... 4 2010-10-01 2010-10-01 false Ash pans. 230.69 Section 230.69 Transportation...MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans § 230.69 Ash pans. Ash pans shall be securely supported from...

2010-10-01

140

Evaporation in space manufacturing  

NASA Technical Reports Server (NTRS)

'Normal evaporation' equations for predicting the compositional changes with time and temperature have been developed and correlated with actual experimental data. An evaporative congruent temperature is defined and used to explain, predict, or plan space experiments on anomalous constitutional melting (on cooling) or solidification (on heating). Uneven evaporation causes reactive jetting forces capable of initiating new convection currents, nongravitational accelerations, surface vibrations, or other disturbances. Applications of evaporation to space manufacturing are described concerning evaporative purification, surface cooling, specimen selection, particles splitting, freezing data interpretation, material loss and dimensional control, and surface contamination or compositional changes.

Li, C. H.

1974-01-01

141

Measuring sub-canopy evaporation in a forested wetland using an ensemble of methods  

NASA Astrophysics Data System (ADS)

Evaporation from the sub-canopy water surface is an integral but understudied component of the water balance in forested wetlands. Previous studies have used eddy covariance, energy balance approaches, and water-table fluctuations to assess whole-system evapotranspiration. However, partitioning evaporation from transpiration is necessary for modeling the system because of different controls over each process. Sub-canopy evaporation is a physically controlled process driven by relatively small gradients in residual energy transmitted through the canopy. The low-energy sub-canopy environment is characterized by a spatiotemporally varying light environment due to sunflecks, small and often inverse temperature and vapor gradients, and a high capacity for heat storage in flood water, which each present challenges to common evapotranspiration measurement techniques. Previous studies have examined wetland surface evaporation rates with small lysimeter experiments, but this approach does not encapsulate micrometeorological processes occurring at the scale of natural wetlands. In this study, we examine a one year time series of in situ sub-canopy flux measurements from a seasonally flooded cypress-tupelo swamp in southeast Louisiana. Our objective is to apply these data towards modeling sub-canopy energy flux responses to intra-annual hydrologic, phenologic, and climatic cycles. To assess and mitigate potential errors due to the inherent measurement challenges of this environment, we utilized multiple measurement approaches including eddy covariance, Bowen ratio energy balance (with both air to air gradients and water surface to air gradients) and direct measurement using a floating evaporation pan. Preliminary results show that Bowen ratio energy balance measurements are useful for constraining evaporation measurements when low wind speed conditions create a non-ideal setting for eddy covariance. However, Bowen ratios were often highly erratic due to the weak temperature and humidity gradients. This suggests the need to use combined methods during periods with problematic boundary layer conditions.

Allen, S. T.; Edwards, B.; Reba, M. L.; Keim, R.

2013-12-01

142

Optimized evaporation from a microchannel heat sink  

NASA Astrophysics Data System (ADS)

Two-phase heat transfer devices, benefiting the unique thermal capacities of phase- change, are considered as the top choice for a wide range of applications involving cooling and temperature control. Evaporation and condensation in these devices usually take place on porous structures. It is widely accepted that they improve the evaporation rates and the overall performance of the device. The liquid menisci formed on the pores of a porous material can be viewed as the active sites of evaporation. Therefore, quantifying the rate of evaporation from a single pore can be used to calculate the total evaporation taking place in the evaporator given the density and the average size of the pores. A microchannel heat sink can be viewed as an structured porous material. In this work, an analytical model is developed to predict the evaporation rate from a liquid meniscus enclosed in a microchannel. The effects of the wall superheat and the width of the channel on the evaporation profile through the meniscus are studied. The results suggest that there is an optimum size for the width of the channel in order to maximize the thermal energy absorbed by the unit area of the heat sink as an array of microchannels.

Monazami, Reza; Haj-Hariri, Hossein

2011-11-01

143

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

144

The evaporation of a drop of mercury  

NASA Astrophysics Data System (ADS)

The evaporative rates of two drops of mercury at room temperature are determined experimentally and theoretically. The resulting mercury vapor levels are estimated and measured, compared with the OSHA permissible exposure limit, and found to be small by comparison.

Winter, Thomas G.

2003-08-01

145

On the evaporation of ammonium sulfate solution  

SciTech Connect

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.

2009-07-16

146

On the evaporation of ammonium sulfate solution.  

PubMed

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. PMID:19861551

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

2009-11-10

147

Pan American Health Organization (PAHO)  

NSDL National Science Digital Library

The Pan American Health Organization (PAHO) is the World Health Organization's regional office for Latin America and the Caribbean. The PAHO Gopher offers a wealth of information specific to health in the 37 member nations of PAHO. Currently, the gopher contains data files on PAHO publications, news and press releases, emergency preparedness and disaster relief, and human resources development, as well as pointers to a variety of health resources.

1997-01-01

148

Experimental performance of new evaporative cooling pad materials  

Microsoft Academic Search

This paper presents performance analysis of two new evaporative cooling pad materials. Now-a-days evaporative cooling pads are commonly made from aspen and khus fibers. These two materials along with new materials namely coconut fibers and palash fibers have been tested in a laboratory using suitably fabricated test set up. Air flow rate was kept constant. Evaporative cooling effectiveness was obtained

J. K. Jain; D. A. Hindoliya

2011-01-01

149

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

150

Water evaporation in silica colloidal deposits.  

PubMed

The results of an experimental study on the evaporation and boiling of water confined in the pores of deposits made of mono-dispersed silica colloidal micro-spheres are reported. The deposits are studied using scanning electron microscopy, adsorption of nitrogen, and adsorption of water through attenuated total reflection-infrared spectroscopy. The evaporation is characterized using differential scanning calorimetry and thermal gravimetric analysis. Optical microscopy is used to observe the patterns on the deposits after evaporation. When heating at a constant rate and above boiling temperature, the release of water out of the deposits is a two step process. The first step is due to the evaporation and boiling of the surrounding and bulk water and the second is due to the desorption of water from the pores. Additional experiments on the evaporation of water from membranes having cylindrical pores and of heptane from silica deposits suggest that the second step is due to the morphology of the deposits. PMID:23928488

Peixinho, Jorge; Lefvre, Grgory; Coudert, Franois-Xavier; Hurisse, Olivier

2013-10-15

151

Measurements of Evaporation Kinetics of Aqueous Aerosols  

NASA Astrophysics Data System (ADS)

The rates of water evaporation and condensation govern the growth, size distribution, and number concentration of cloud droplets, yet the details of these fundamental processes remain poorly understood. In this work, the effect of acetic acid on the evaporation rate of water is studied using a liquid microjet technique. A collimated train of micron-sized droplets containing 1M acetic acid is injected into a vacuum chamber, and their temperature is measured at various distances from the jet nozzle using Raman thermometry. The data are compared to an evaporative cooling model to determine the evaporation coefficient, ?. In previous studies, ? was determined for pure water, D2O, 3M ammonium sulfate, and 4M sodium perchlorate to be 0.62 0.09, 0.57 0.06, 0.58 0.05, and 0.47 0.02, respectively. It is hypothesized that more surface-active species have a greater effect on evaporation rates. Acetic acid has been shown to be surface-active and is therefore representative of the small, surfactant-like molecules often found in aerosols. Preliminary results show a slight reduction in the evaporation coefficient for acetic acid compared to pure water. These experimental findings are being compared with calculations from the Chandler group at UC Berkeley in order to better understand the molecular mechanism of water evaporation.

Duffey, K.; Shih, O.; Liu, F.; Saykally, R.; Cohen, R. C.

2011-12-01

152

Pan-Canadian Study of Reading Volumes  

Cancer.gov

Pan Pan - -Canadian Study of Canadian Study of Reading Volumes Reading Volumes Andrew J. Coldman Diane Major Gregory Doyle Yulia Dyachkova Norm Phillips Jay Onysko Rene Shumak Norah Smith Nancy Wadden Measuring Radiologist Skill Measuring Radiologist

153

The Effect of Nitrogen Gas Flow Rate on the Properties of TiN-COATED High-Speed Steel (hss) Using Cathodic Arc Evaporation Physical Vapor Deposition (pvd) Technique  

NASA Astrophysics Data System (ADS)

Cathodic arc evaporation (CAE) is a widely-used technique for generating highly ionized plasma from which hard and wear resistant physical vapor deposition (PVD) coatings can be deposited. A major drawback of this technique is the emission of micrometer-sized droplets of cathode material from the arc spot, which are commonly referred to as "macroparticles." In present study, titanium nitride (TiN) coatings on high-speed steel (HSS) coupons were produced with a cathodic arc evaporation technique. We studied and discussed the effect of various nitrogen gas flow rates on microstructural and mechanical properties of TiN-coated HSS coupons. The coating properties investigated in this work included the surface morphology, thickness of deposited coating, adhesion between the coating and substrate, coating composition, coating crystallography, hardness and surface characterization using a field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD) with glazing incidence angle (GIA) technique, scratch tester, hardness testing machine, surface roughness tester, and atomic force microscope (AFM). An increase in the nitrogen gas flow rate showed decrease in the formation of macro-droplets in CAE PVD technique. During XRD-GIA studies, it was observed that by increasing the nitrogen gas flow rate, the main peak [1,1,1] shifted toward the lower angular position. Surface roughness decreased with an increase in nitrogen gas flow rate but was higher than the uncoated polished sample. Microhardness of TiN-coated HSS coupons showed more than two times increase in hardness than the uncoated one. Scratch tester results showed good adhesion between the coating material and substrate. Considerable improvement in the properties of TiN-deposited thin films was achieved by the strict control of all operational steps.

Mubarak, Ali; Hamzah, Esah Binti; Mohd Toff, Mohd Radzi Hj.; Hashim, Abdul Hakim Bin

154

African Drum and Steel Pan Ensembles.  

ERIC Educational Resources Information Center

Discusses how to develop both African drum and steel pan ensembles providing information on teacher preparation, instrument choice, beginning the ensemble, and lesson planning. Includes additional information for the drum ensembles. Lists references and instructional materials, sources of drums and pans, and common note layout/range for steel pan

Sunkett, Mark E.

2000-01-01

155

Evaporation, Boiling and Bubbles  

ERIC Educational Resources Information Center

Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The

Goodwin, Alan

2012-01-01

156

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 ...

157

Flexible microprocessor-based evaporation controller  

NASA Astrophysics Data System (ADS)

Electron beam evaporation sources require two power supplies, one each for the filament current and the electron acceleration. To obtain a stable deposition rate, the emission current between filament and target must remain constant. During film deposition, slight geometry changes in the evaporator cause significant rate variations, making constant readjustment of the emission current necessary. While in commercial solutions, analog feedback regulators are often used to perform this task, these controllers cannot easily be adapted to home-built evaporation sources. The microcontrolled feedback controller presented here is more flexible and versatile than the commercial solutions. The controller can be easily modified to work with different external power supplies and allows the easy upgrade of most existing electron beam evaporation setups. A serial-port computer interface completely integrates the controller into the automated laboratory environment.

Meyer Zu Heringdorf, F.-J.; Belton, A. C.

2004-12-01

158

Flash evaporator systems test  

NASA Technical Reports Server (NTRS)

A flash evaporator heat rejection system representative of that proposed for the space shuttle orbiter underwent extensive system testing at the NASA Johnson Space Center (JSC) to determine its operational suitability and to establish system performance/operational characteristics for use in the shuttle system. During the tests the evaporator system demonstrated its suitability to meet the shuttle requirements by: (1) efficient operation with 90 to 95% water evaporation efficiency, (2) control of outlet temperature to 40 + or - 2 F for partial heat load operation, (3) stability of control system for rapid changes in Freon inlet temperature, and (4) repeated dormant-to-active device operation without any startup procedures.

Dietz, J. B.

1976-01-01

159

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

160

CAPSULE REPORT: EVAPORATION PROCESS  

EPA Science Inventory

Evaporation has been an established technology in the metal finishing industry for many years. In this process, wastewaters containing reusable materials, such as copper, nickel, or chromium compounds are heated, producing a water vapor that is continuously removed and condensed....

161

Polarization (ellipsometric) measurements of liquid condensate deposition and evaporation rates and dew points in flowing salt/ash-containing combustion gases  

NASA Technical Reports Server (NTRS)

An application of an optical polarization technique in a combustion environment is demonstrated by following, in real-time, growth rates of boric oxide condensate on heated platinum ribbons exposed to seeded propane-air combustion gases. The results obtained agree with the results of earlier interference measurements and also with theoretical chemical vapor deposition predictions. In comparison with the interference method, the polarization technique places less stringent requirements on surface quality, which may justify the added optical components needed for such measurements.

Seshadri, K.; Rosner, D. E.

1985-01-01

162

The Pan-STARRS Moving Object Processing System  

NASA Astrophysics Data System (ADS)

We describe the Pan-STARRS Moving Object Processing System (MOPS), a modern software package that produces automatic asteroid discoveries and identifications from catalogs of transient detections from next-generation astronomical survey telescopes. MOPS achieves >99.5% efficiency in producing orbits from a synthetic but realistic population of asteroids whose measurements were simulated for a Pan-STARRS4-class telescope. Additionally, using a nonphysical grid population, we demonstrate that MOPS can detect populations of currently unknown objects such as interstellar asteroids. MOPS has been adapted successfully to the prototype Pan-STARRS1 telescope despite differences in expected false detection rates, fill-factor loss, and relatively sparse observing cadence compared to a hypothetical Pan-STARRS4 telescope and survey. MOPS remains highly efficient at detecting objects but drops to 80% efficiency at producing orbits. This loss is primarily due to configurable MOPS processing limits that are not yet tuned for the Pan-STARRS1 mission. The core MOPS software package is the product of more than 15 person-years of software development and incorporates countless additional years of effort in third-party software to perform lower-level functions such as spatial searching or orbit determination. We describe the high-level design of MOPS and essential subcomponents, the suitability of MOPS for other survey programs, and suggest a road map for future MOPS development.

Denneau, Larry; Jedicke, Robert; Grav, Tommy; Granvik, Mikael; Kubica, Jeremy; Milani, Andrea; Vere, Peter; Wainscoat, Richard; Chang, Daniel; Pierfederici, Francesco; Kaiser, N.; Chambers, K. C.; Heasley, J. N.; Magnier, Eugene A.; Price, P. A.; Myers, Jonathan; Kleyna, Jan; Hsieh, Henry; Farnocchia, Davide; Waters, Chris; Sweeney, W. H.; Green, Denver; Bolin, Bryce; Burgett, W. S.; Morgan, J. S.; Tonry, John L.; Hodapp, K. W.; Chastel, Serge; Chesley, Steve; Fitzsimmons, Alan; Holman, Matthew; Spahr, Tim; Tholen, David; Williams, Gareth V.; Abe, Shinsuke; Armstrong, J. D.; Bressi, Terry H.; Holmes, Robert; Lister, Tim; McMillan, Robert S.; Micheli, Marco; Ryan, Eileen V.; Ryan, William H.; Scotti, James V.

2013-04-01

163

Evaporation of Lennard-Jones fluids.  

PubMed

Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature T/T(c), where T(c) is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase. PMID:21682530

Cheng, Shengfeng; Lechman, Jeremy B; Plimpton, Steven J; Grest, Gary S

2011-06-14

164

On modeling evaporation  

Microsoft Academic Search

We develop a theoretical model for evaporation of a pure liquid drop on a thermally conductive solid substrate. We discuss\\u000a a variety of effects regarding evaporation regime, the state of the liquid\\/gas interface and the content of gas phase. Then,\\u000a we further consider two models: the one resulting from the one-sided non-equilibrium assumption and the other that assumes\\u000a diffusion-limited regime

Nebojsa Murisic; Lou Kondic

2008-01-01

165

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) [Schenectady, NY; Kosky, Philip G. (Ballston Lake, NY) [Ballston Lake, NY

1982-01-01

166

An electronic pan/tilt/zoom camera system  

NASA Astrophysics Data System (ADS)

A small camera system is described for remote viewing applications that employs fisheye optics and electronics processing for providing pan, tilt, zoom, and rotational movements. The fisheye lens is designed to give a complete hemispherical FOV with significant peripheral distortion that is corrected with high-speed electronic circuitry. Flexible control of the viewing requirements is provided by a programmable transformation processor so that pan/tilt/rotation/zoom functions can be accomplished without mechanical movements. Images are presented that were taken with a prototype system using a CCD camera, and 5 frames/sec can be acquired from a 180-deg FOV. The image-tranformation device can provide multiple images with different magnifications and pan/tilt/rotation sequences at frame rates compatible with conventional video devices. The system is of interest to the object tracking, surveillance, and viewing in constrained environments that would require the use of several cameras.

Zimmermann, Steve; Martin, H. L.

1992-08-01

167

Sheet Membrane Spacesuit Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

A document describes a sheet membrane spacesuit water membrane evaporator (SWME), which allows for the use of one common water tank that can supply cooling water to the astronaut and to the evaporator. Test data showed that heat rejection performance dropped only 6 percent after being subjected to highly contaminated water. It also exhibited robustness with respect to freezing and Martian atmospheric simulation testing. Water was allowed to freeze in the water channels during testing that simulated a water loop failure and vapor backpressure valve failure. Upon closing the backpressure valve and energizing the pump, the ice eventually thawed and water began to flow with no apparent damage to the sheet membrane. The membrane evaporator also serves to de-gas the water loop from entrained gases, thereby eliminating the need for special degassing equipment such as is needed by the current spacesuit system. As water flows through the three annular water channels, water evaporates with the vapor flowing across the hydrophobic, porous sheet membrane to the vacuum side of the membrane. The rate at which water evaporates, and therefore, the rate at which the flowing water is cooled, is a function of the difference between the water saturation pressure on the water side of the membrane, and the pressure on the vacuum side of the membrane. The primary theory is that the hydrophobic sheet membrane retains water, but permits vapor pass-through when the vapor side pressure is less than the water saturation pressure. This results in evaporative cooling of the remaining water.

Bue, Grant; Trevino, Luis; Zapata, Felipe; Dillion, Paul; Castillo, Juan; Vonau, Walter; Wilkes, Robert; Vogel, Matthew; Frodge, Curtis

2013-01-01

168

Mobile evaporator corrosion test results  

SciTech Connect

Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

Rozeveld, A.; Chamberlain, D.B.

1997-05-01

169

Pan-information Location Map  

NASA Astrophysics Data System (ADS)

A huge amount of information, including geographic, environmental, socio-economic, personal and social network information, has been generated from diverse sources. Most of this information exists separately and is disorderly even if some of it is about the same person, feature, phenomenon or event. Users generally need to collect related information from different sources and then utilize them in applications. An automatic mechanism, therefore, for establishing a connection between potentially-related information will profoundly expand the usefulness of this huge body of information. A connection tie is semantic location describing semantically concepts and attributes of locations as well as relationships between locations, since 80% of information contains some kind of geographic reference but not all of geographic reference has explicit geographic coordinates. Semantic location is an orthogonal form of location representation which can be represented as domain ontology or UML format. Semantic location associates various kinds of information about a same object to provide timely information services according to users' demands, habits, preferences and applications. Based on this idea, a Pan-Information Location Map (PILM) is proposed as a new-style 4D map to associates semantic location-based information dynamically to organize and consolidate the locality and characteristics of corresponding features and events, and delivers on-demand information with a User-Adaptive Smart Display (UASD).

Zhu, X. Y.; Guo, W.; Huang, L.; Hu, T.; Gao, W. X.

2013-11-01

170

Dry deposition of PAN to grassland vegetation.  

National Technical Information Service (NTIS)

Peroxyacetyl nitrate or PAN (CH(sub 3)C(O)OONO(sub 2)) is formed in the lower troposphere via photochemical reactions involving nitrogen oxides (NO(sub x)) and non-methane hydrocarbons (NMHCs). PAN has a lifetime in the free troposphere of about three mon...

P. V. Doskey M. L. Wesely D. R. Cook W. Gao

1994-01-01

171

A Hundred Years of Peter Pan  

ERIC Educational Resources Information Center

The centenary of the first performance of J. M. Barrie's Peter Pan was celebrated in December 2004. Taking account of the various events in Britain to mark the occasion--newspaper articles, radio and television programmes, retrospects in the original theatre--this article examines the status and popularity of Peter Pan after a hundred years. The

Hollindale, Peter

2005-01-01

172

Peroxyacetyl nitrate (PAN) in the urban atmosphere.  

PubMed

Peroxyacetyl nitrate (PAN) in air has been well known as the indicator of photochemical smog due to its frequent occurrences in Seoul metropolitan area. This study was implemented to assess the distribution characteristics of atmospheric PAN in association with relevant parameters measured concurrently. During a full year period in 2011, PAN was continuously measured at hourly intervals at two monitoring sites, Gwang Jin (GJ) and Gang Seo (GS) in the megacity of Seoul, South Korea. The annual mean concentrations of PAN during the study period were 0.640.49 and 0.570.46 ppb, respectively. The seasonal trends of PAN generally exhibited dual peaks in both early spring and fall, regardless of sites. Their diurnal trends were fairly comparable to each other. There was a slight time lag (e.g., 1 h) in the peak occurrence pattern between O3 and PAN, as the latter trended to peak after the maximum UV irradiance period (16:00 (GJ) and 17:00 (GS)). The concentrations of PAN generally exhibited strong correlations with particulates. The results of this study suggest that PAN concentrations were affected sensitively by atmospheric stability, the wet deposition of NO2, wind direction, and other factors. PMID:23838043

Lee, Jun-Bok; Yoon, Joong-Sup; Jung, Kweon; Eom, Seok-Won; Chae, Young-Zoo; Cho, Seog-Ju; Kim, Shin-Do; Sohn, Jong Ryeul; Kim, Ki-Hyun

2013-11-01

173

A variational approach for pan-sharpening.  

PubMed

Pan-sharpening is a process of acquiring a high resolution multispectral (MS) image by combining a low resolution MS image with a corresponding high resolution panchromatic (PAN) image. In this paper, we propose a new variational pan-sharpening method based on three basic assumptions: 1) the gradient of PAN image could be a linear combination of those of the pan-sharpened image bands; 2) the upsampled low resolution MS image could be a degraded form of the pan-sharpened image; and 3) the gradient in the spectrum direction of pan-sharpened image should be approximated to those of the upsampled low resolution MS image. An energy functional, whose minimizer is related to the best pan-sharpened result, is built based on these assumptions. We discuss the existence of minimizer of our energy and describe the numerical procedure based on the split Bregman algorithm. To verify the effectiveness of our method, we qualitatively and quantitatively compare it with some state-of-the-art schemes using QuickBird and IKONOS data. Particularly, we classify the existing quantitative measures into four categories and choose two representatives in each category for more reasonable quantitative evaluation. The results demonstrate the effectiveness and stability of our method in terms of the related evaluation benchmarks. Besides, the computation efficiency comparison with other variational methods also shows that our method is remarkable. PMID:23613044

Fang, Faming; Li, Fang; Shen, Chaomin; Zhang, Guixu

2013-07-01

174

Surface energy partitioning during evaporation from drying porous media (Invited)  

NASA Astrophysics Data System (ADS)

The partitioning of incoming radiative energy over evaporating natural surfaces affects mass and energy exchange rates with the atmosphere, and surface temperature often used for remote estimation of fluxes. The coupling between evaporation flux and surface temperature is modeled in a representative unit cell composed of a pore and surrounding dry surface. An analytical solution for the surface temperature was derived based on pore scale diffusion model for the evaporative flux coupled with surface energy balance including heat exchange across pore walls. Model predictions for evaporative flux and thermal field during drying were in good agreement with experimental results. The analysis shows that commonly assumed isothermal evaporation conditions (where surface and air temperatures are similar) may yield 15 to 40% overestimation in evaporation rates relative to non-isothermal conditions (where evaporation rates affect surface temperature). Theoretical results suggest that for high shortwave radiation values, most evaporating surfaces will gradually warm up and enhance evaporation rates relative to isothermal conditions. The model was used to predict the evolution of surface energy partitioning and concurrent changes in the Bowen ratio and ? parameter of the Priestley-Taylor relations for a range of surfaces and climatic conditions. Applications for remote sensing and large scale inferences will be discussed.

Or, D.; Aminzadeh, M.

2013-12-01

175

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

176

Evaporation-induced cavitation in nanofluidic channels.  

PubMed

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 -7MPa. 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. PMID:22343530

Duan, Chuanhua; Karnik, Rohit; Lu, Ming-Chang; Majumdar, Arun

2012-03-01

177

Thermal signatures help deduce evaporative fluxes into turbulent airflows  

NASA Astrophysics Data System (ADS)

Evaporative fluxes and energy balance of terrestrial surfaces are affected by interplay between water availability, energy input, and exchange across the air boundary layer. Commonly occurring turbulent airflows impose complex and highly dynamic boundary conditions that challenge prediction of surface evaporation rates. During stage-I evaporation where the vaporization plane is at the surface, intermittent turbulent interactions with the surface give rise to distinct thermal signatures that could be recorded using infrared thermography (IRT). The study links measured thermal signatures with spatio-temporal distribution of eddy-induced localized evaporation rates towards characterization of turbulent momentum field and estimation of overall evaporative fluxes. Results highlight potential of the approach for remote quantification of interactions between turbulent eddies and evaporating surfaces. Surface thermal inertia present a challenge to high resolution implementation, and strategies for overcoming these are presented including applications to plant canopies (low thermal inertia surfaces). Applications for larger scales will be discussed.

Haghighi, E.; Or, D.

2013-12-01

178

Control of the thickness distribution of evaporated functional electroceramic NTC thermistor thin films  

Microsoft Academic Search

In this work the thickness distribution of NTC thermistor thin films produced by low deposition rate (0.8nms?1) electron-beam evaporation is investigated. The target preparation, deposition conditions and geometrical set-up of the evaporation mechanism are described in detail. The evaporation geometry is shown to be critical for the thickness distribution of evaporated films. The film thickness distribution of evaporated layers was

R. Schmidt; M. Parlak; A. W. Brinkman

2008-01-01

179

The continuous similarity model of bulk soil-water evaporation  

NASA Technical Reports Server (NTRS)

The continuous similarity model of evaporation is described. In it, evaporation is conceptualized as a two stage process. For an initially moist soil, evaporation is first climate limited, but later it becomes soil limited. During the latter stage, the evaporation rate is termed evaporability, and mathematically it is inversely proportional to the evaporation deficit. A functional approximation of the moisture distribution within the soil column is also included in the model. The model was tested using data from four experiments conducted near Phoenix, Arizona; and there was excellent agreement between the simulated and observed evaporation. The model also predicted the time of transition to the soil limited stage reasonably well. For one of the experiments, a third stage of evaporation, when vapor diffusion predominates, was observed. The occurrence of this stage was related to the decrease in moisture at the surface of the soil. The continuous similarity model does not account for vapor flow. The results show that climate, through the potential evaporation rate, has a strong influence on the time of transition to the soil limited stage. After this transition, however, bulk evaporation is independent of climate until the effects of vapor flow within the soil predominate.

Clapp, R. B.

1983-01-01

180

Combined Evaporation and Salt Precipitation in Porous Media  

NASA Astrophysics Data System (ADS)

The vadose zone pore water contains dissolved salts and minerals; therefore, evaporation results in high rates of salt accumulation that may change the physical and chemical properties of the porous media. Here, a series of experiments, together with a mathematical model, are presented to shed new light on these processes. Experiments included: (1) long-term column evaporation experiments to quantify changes in evaporation rates due to salt precipitation; (2) CT scans of evaporated porous media samples saturated with salt solutions, to observe salt precipitation from micro to macro scales; and (3) Infrared thermography analysis to quantify evaporation rates from porous media surfaces for homogeneous and heterogeneous conditions and constant water table, in the presence of salt precipitation. As expected, the majority of salt crystallization occurs in the upper parts of the matrix, near the evaporation front. For heterogeneous porous matrices, salt precipitation will occur mainly in the fine pore regions as preferential evaporation takes place in these locations. In addition, it was found that the precipitated NaCl salt crust diffusion coefficient for water vapor is one to two orders of magnitude lower than the vapor diffusion coefficient in free air, depending on environmental conditions and salt crystallization rates. Three new stages of evaporation were defined for saline solutions: SS1, SS2 and SS3. SS1 exhibits a low and gradual decrease in the evaporation rate due to osmotic pressure. During SS2, the evaporation rate falls progressively due to salt precipitation; SS3 is characterized by a constant low evaporation rate and determined by the diffusion rate of water vapor through the precipitated salt layer. Even though phenomenologically similar to the classical evaporation stages of pure water, these stages correspond to different mechanisms and the transition between stages can occur regardless the hydraulic conditions. As well, it was shown that matrix heterogeneity lessens the salt effect on evaporation as coarse pore regions are relatively free of salt crystals, facilitating vapor transport towards the atmosphere. This was verified by the thermography analysis that enabled independent quantification of evaporation rates from coarse and fine sections of the media during salt precipitation. This is in contrast to homogeneous conditions, where the salt is distributed homogeneously in the matrix's upper parts, resulting in an increase in matrix resistivity to vapor flow. This research sheds new light on the dynamics of the evaporation process of a saline solution and the importance of considering that natural pore solutions typically include electrolytes.

Weisbrod, N.; Dragila, M. I.; Nachshon, U.; Or, D.; Shaharani, E.; Grader, A.

2012-12-01

181

MEASURING EVAPORATION AND SEEPAGE LOSSES FROM LAGOONS USED TO CONTAIN ANIMAL WASTE  

Microsoft Academic Search

Seepage (S) from animal-waste lagoons was estimated using a water balance approach by measuring changes in waste level (i.e., depth) (?D) and evaporation (E) over brief periods (e.g., 6 days) when all other inflow and outflow were precluded. Data were collected at commercial swine and cattle feedlots in southwestern Kansas. Precision waste level recorders, floating evaporation pans, and meteorological models

J. M. Ham

1999-01-01

182

Mass Balance Analyses of Flushing, Evaporation, Infiltration, and Biological Activity in California Park Lakes, Butte County, California  

NASA Astrophysics Data System (ADS)

California Park Lakes are retained by dams on Dead Horse Slough, an ephemeral stream network, which flows over volcanic/sedimentary rocks of the Tuscan Formation at the eastern margin of the Sacramento Valley, Butte County, California. Surface area of the lakes is approximately 0.2 km2, maximum depth is 8 m, and approximate lake volume is 700,000 m3. Flow rate and depth measurements in Dead Horse Slough indicate that discharges associated with winter storms flush the lakes repeatedly. During dry summer months no surface water discharges from the lakes and water is pumped from the underlying aquifer to maintain the water level. Average pumping rates are approximately 1250 m3/day. Surface and storm drain runoff, mainly from nearby lawn irrigation, also supply water at fluctuating rates estimated to equal a fraction (e.g., 35 percent) of well water supply. Reported pan evaporation data indicate that summer evaporation from lake surfaces is 1000 to 1500 m3/day. Thus, the estimated evaporation rate approximately equals the well water and runoff supply rate. Periodic chemical analyses of water supplies and lake water have been conducted primarily to evaluate nutrient sources. Typical nitrate and chloride concentrations are 2 to 10 mg/liter, and typical phosphate concentrations are 0.2 to 1 mg/liter. Chloride concentrations in lake water during summer 2002 increased slightly corresponding closely to mass balance calculations for evaporative concentration. Infiltration (including leakage through the terminal dam) is small relative to evaporation and difficult to measure within the uncertainty of chloride measurements and water mass balance estimates. Lake concentrations of nitrate and phosphate are generally lower than source water concentrations consistent with biological consumption. Mass balance analyses of dissolved nutrients in lakes and water sources compared to chloride provide a measure of the rate of biological activity in the lakes, which is a water quality management issue. Characterization of flushing, evaporation, and biological activity in California Park Lakes using water and chemical mass balance analyses contributes to water quality management and provides constraints on infiltration into the Tuscan Formation, which is the primary regional aquifer for domestic water supplies.

Murphy, W. M.; Sundermann, C. R.

2002-12-01

183

High Vacuum Evaporation System.  

National Technical Information Service (NTIS)

The primary objective of the electron beam evaporator is to apply high quality optical coatings for lasers operating in the midinfrared region (2-5 micron) band, as well as lasers emitting in the range of 0.7 - 1.0 micron wavelength. The electron beam eva...

M. Razeghi

1996-01-01

184

Incorporated evaporative condenser  

Microsoft Academic Search

The incorporated evaporative condenser developed in this work comprises of a system of fins, basin of water condensates, circuit pump and system of drop cloud via spraying. In the whole provision a system of drop collector is also included for the minimisation of water escapes now essential for the operation of system. Actually, the present work aims on the development

Michalis Gr. Vrachopoulos; Andronikos E. Filios; Georgios T. Kotsiovelos; Eleftherios D. Kravvaritis

2007-01-01

185

Evaporative roof cooling system  

Microsoft Academic Search

An evaporative roof cooling system is described for placement upon a roof surface exposed to relatively high levels of solar radiation causing high under roof temperatures and comprising: (a) water distribution mist\\/spray nozzles positioned on the roof surface for supplying substantially uniform mist\\/sprays of water to lay down a substantially uniform thin film of water on the roof surface; (b)

Viner

1988-01-01

186

Water Evaporation Test  

NSDL National Science Digital Library

In this activity, learners conduct an experiment to measure the temperature of a dry cotton ball versus a wet one. Explore water evaporation and investigate why swimming and drinking water keeps your body cool. This activity guide includes a step-by-step instructional video.

Center, Saint L.

2013-01-17

187

Evaporation of extrasolar planets  

Microsoft Academic Search

This article presents a review on the observations and theoretical modeling of the evaporation of extrasolar planets. The observations and the resulting constraints on the upper atmosphere (thermosphere and exosphere) of the ``hot-Jupiters'' are described. The early observations of the first discovered transiting extrasolar planet, HD209458b, allowed the discovery that this planet has an extended atmosphere of escaping hydrogen. Subsequent

A. Lecavelier Des Etangs

2010-01-01

188

Spacesuit Evaporator-Absorber-Radiator (SEAR)  

NASA Technical Reports Server (NTRS)

For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

2011-01-01

189

Pan coefficient ( K p) estimation under uncertainty on fetch  

NASA Astrophysics Data System (ADS)

The FAO Penman-Monteith (F-PM) method is a frequently applied approach for calculating the daily reference evapotranspiration (ET0). This method requires long records of meteorological data, which makes it quite hard to employ in locations with no or limited available data. Evaporation pans are widely used to estimate the reference ET0, but this method requires reliable estimates of the pan coefficient ( K p). The objectives of this study were to determine the proper values of monthly and annual K p, as well as the best method among those available for the estimation of K p values in the study area. Measured weather data from 1992 to 2006 were obtained from 18 stations in the North and Northwest of Iran. Daily ET0 calculated using methods by Bernardo et al. and Pereira et al. were compared with those calculated by the F-PM method. The employed methods at all stations, except those located in the north of the study area with high relative humidity, overestimated the ET0 compared to the F-PM method. The constant parameters of these methods were optimized by a trial and error scheme to minimize the root mean square error. The results indicated that modified K p coefficients from Bernardo et al.'s method ranged between 0.41 and 0.87 and the optimal coefficient of Pereira et al.'s method ranged between 0.49 and 0.95. Modified monthly K p from Bernardo et al.'s method ranged between 0.3 and 1.07 and those from Pereira et al.'s method ranged between 0.4 and 1.18. Modified K p of the methods by Bernardo et al. and Pereira et al. showed the higher estimation accuracy of daily ET0 values. In general, the performance of the modified K p of Bernardo et al.'s method was higher than Pereira et al.'s method for all stations. Thus, in the study region and under the same climatic conditions [in areas with only pan evaporation ( E p) records], the use of climatic monthly modified K p to calculate ET0 based on class A E p is recommended.

Mohammadi, M.; Ghahraman, B.; Davary, K.; Liaghat, A. M.; Bannayan, M.

2012-07-01

190

Studies on the evaporation of crude oil and petroleum products II. Boundary layer regulation  

Microsoft Academic Search

Experiments were conducted to determine if oil and petroleum evaporation is regulated by the saturation of the air boundary layer. Experiments included the examination of the evaporation rate with and without wind. It was found that evaporation rates were similar for all wind conditions, but lower for the no-wind conditions. Experiments where the area and mass varied showed that boundary

Merv F. Fingas

1998-01-01

191

Temperature field beneath evaporating surface resolved by infrared thermography  

NASA Astrophysics Data System (ADS)

Land-atmosphere mass exchange is intimately linked with radiation and energy balance of terrestrial surfaces. Surface evaporation is a key hydrologic flux affected by interplay between water supply from below, surface energy input, and exchange across air boundary layer. The thermal signature depression of an evaporating surface is proportional to the magnitude of the flux which makes remote monitoring of fluxes from heterogeneous surface feasible using advanced Infrared thermography (IRT). Inversion of IRT data to evaporation fluxes relies on knowledge of thickness of thermal depression beneath evaporation zone. We develop a mathematical model for 3D temperature field induced by evaporation from a patchy evaporative surface and compare the results with direct IRT measurements of cross section beneath an evaporating surface. Results yield a universal description of evaporative temperature depression that could serve for predicting spatial and temporal evaporation rates distributions based on IRT data. The thickness of thermo-evaporative zone is typically in the range of 10-40 mm for a wide range of soil properties and fluxes.

Shahraeeni, Ebrahim; Or, Dani

2010-05-01

192

Evaporative cooling of antiprotons for the production of trappable antihydrogen  

SciTech Connect

We describe the implementation of evaporative cooling of charged particles in the ALPHA apparatus. Forced evaporation has been applied to cold samples of antiprotons held in Malmberg-Penning traps. Temperatures on the order of 10 K were obtained, while retaining a significant fraction of the initial number of particles. We have developed a model for the evaporation process based on simple rate equations and applied it succesfully to the experimental data. We have also observed radial re-distribution of the clouds following evaporation, explained by simple conservation laws. We discuss the relevance of this technique for the recent demonstration of magnetic trapping of antihydrogen.

Silveira, D. M.; Cesar, C. L. [Instituto de Fisica - Universidade Federal do Rio de Janeiro, 21941-972, Rio de Janeiro (Brazil); Andresen, G. B.; Bowe, P. D.; Hangst, J. S. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M. D.; Hayden, M. E. [Department of Physics, Simon Fraser University, Burnaby BC, V5A 1S6 (Canada); Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S. [Department of Physics, University of California, Berkeley, California 94720-7300 (United States); Bertsche, W. [School of Physics and Astronomy, University of Manchester, M13 9PL Manchester (United Kingdom) and Cockroft Institute, WA4 4AD Warrington (United Kingdom); Butler, E. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Charlton, M.; Madsen, N.; Werf, D. P. van der [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Friesen, T.; Hydomako, R. [Department of Physics and Astronomy, University of Calgary AB, T2N 1N4 (Canada); and others

2013-03-19

193

Modeling of Droplet Evaporation from a Nebulizer in an Inductively Coupled Plasma.  

National Technical Information Service (NTIS)

The evaporation rate of sample droplets in an inductively coupled plasma is investigated through the development of two models using the direct simulation Monte Carlo technique. A standard continuum evaporation model is contrasted with a kinetic technique...

C. M. Benson S. F. Gimelshein D. A. Levin A. Montaser

2000-01-01

194

Analytical solution for soil water redistribution during evaporation process.  

PubMed

Simulating the dynamics of soil water content and modeling soil water evaporation are critical for many environmental and agricultural strategies. The present study aims to develop an analytical solution to simulate soil water redistribution during the evaporation process. This analytical solution was derived utilizing an exponential function to describe the relation of hydraulic conductivity and water content on pressure head. The solution was obtained based on the initial condition of saturation and an exponential function to model the change of surface water content. Also, the evaporation experiments were conducted under a climate control apparatus to validate the theoretical development. Comparisons between the proposed analytical solution and experimental result are presented from the aspects of soil water redistribution, evaporative rate and cumulative evaporation. Their good agreement indicates that this analytical solution provides a reliable way to investigate the interaction of evaporation and soil water profile. PMID:24355839

Teng, Jidong; Yasufuku, Noriyuki; Liu, Qiang; Liu, Shiyu

2013-01-01

195

STEREO Sees Comet Pan-STARRS  

NASA Video Gallery

In early March 2013, Comet PanSTARRS became visible to the naked eye in the night sky in the Northern Hemisphere, appearing with a similar shape and brightness as a star, albeit with a trailing tai...

196

White Pan Bread Marketing Spreads Methodology.  

National Technical Information Service (NTIS)

Explained is the methodology used in the USDA marketing spreads series for white pan bread which involves price spreads, farm value of ingredients, and cost of farm ingredients to flour millers and bakeries. Ingredients have changed in relation to changes...

L. D. Schnake

1983-01-01

197

Making alloy foils by electron-beam evaporation  

Microsoft Academic Search

The electron beam evaporation of various metals and alloys, including Ti-; -6 Al--4 V, Inconel 800, zirconium, and stainless steel is discussed. The ; condensation of such evaporants to a freestanding foil is examined with regard to ; alloy composition control and foil metallurgy. Operating experience is also ; covered with consideration of source power efficiencies, deposition rates, and ;

1974-01-01

198

Hybrid Evaporative - Condenser Cooling Tower  

Microsoft Academic Search

The need to save energy in power producing and power consuming systems and the fact that evaporative cooling is the most efficient method for heat rejection led to the design and testing of a model of a special cooling tower, fn this hybrid system an evaporative condenser is being built into the cooling tower and the advantages of evaporative cooling

Uriyel Fisher; Wolfgang Leidenfrost; Jiashang Li

1981-01-01

199

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

200

Evaporative Cooling of Antiprotons to Cryogenic Temperatures  

SciTech Connect

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal.

Andresen, G. B.; Bowe, P. D.; Hangst, J. S. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M. D.; Hayden, M. E. [Department of Physics, Simon Fraser University, Burnaby BC, V5A 1S6 (Canada); Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S. [Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300 (United States); Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A.; Madsen, N.; Werf, D. P. van der; Wilding, D. [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); Cesar, C. L.; Lambo, R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil)

2010-07-02

201

Evaporative cooling of antiprotons to cryogenic temperatures.  

PubMed

We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future experiments. The technique opens up new possibilities for cooling of trapped ions and is of particular interest in antiproton physics, where a precise CPT test on trapped antihydrogen is a long-standing goal. PMID:20867439

Andresen, G B; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A; Hydomako, R; Jonsell, S; Kurchaninov, L; Lambo, R; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wilding, D; Wurtele, J S; Yamazaki, Y

2010-07-01

202

An indirect evaporative chiller  

Microsoft Academic Search

A novel indirect evaporative chiller driven by outdoor dry air to produce cold water as the cooling source for air conditioning\\u000a systems is introduced, and the principle and the structure of the chiller is presented. The cold water can be produced almost\\u000a reversibly under ideal working conditions, with its temperature infinitely close to the dew point temperature of the inlet

Xiaoyun Xie; Yi Jiang

2010-01-01

203

Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

Ungar, Eugene K.; Almlie, Jay C.

2010-01-01

204

A comparison of several methods of estimating the evaporation of Lake Flevo  

Microsoft Academic Search

Evaporation has been computed for a large shallow lake according to the water balance method, the energy budget method, the bulk aerodynamic method, Penman's method and the pan factor method. Data for all meteorological methods were collected at one main station in the centre of the lake. At several other recording stations in and around the lake data for the

J. Q. Keijman; R. W. R. Koopmans

205

Evaluation and generalization of radiation-based methods for calculating evaporation  

NASA Astrophysics Data System (ADS)

Eight radiation-based equations for determining evaporation were evaluated and expressed in five generalized forms. Five evaporation equations (Abtew, Hargreaves, Makkink, Priestley and Taylor and Turc), where each represents one generalized form, were then compared with pan evaporation measured at Changins station in Switzerland. The comparison was first made using the original constant values involved in each equation, and then using the recalibrated constant values. Evaluation of the Priestley and Taylor equation requires net radiation data as input, in this study, net radiation was estimated using Equation (16) owing to the lack of observation data. The results showed that when the original constant values were used, large errors resulted for most of the equations. When recalibrated constant values were substituted for the original constant values, four of the five equations improved greatly, and all five equations performed well for determining mean annual evaporation. For seasonal and monthly evaporation, the Hargreaves and Turc equations showed a significant bias, especially for cold months. With properly determined constant values, the Makkink and modified Priestley and Taylor equations resulted in monthly evaporation values that agreed most closely with pan evaporation in the study region. The simple Abtew equation can also be used when other meteorological data except radiation are not available.

Xu, C.-Y.; Singh, V. P.

2000-02-01

206

Infrared thermography of evaporative fluxes and dynamics of salt deposition on heterogeneous porous surfaces  

NASA Astrophysics Data System (ADS)

Evaporation of saline solutions from porous media, common in arid areas, involves complex interactions between mass transport, energy exchange and phase transitions. We quantified evaporation of saline solutions from heterogeneous sand columns under constant hydraulic boundary conditions to focus on effects of salt precipitation on evaporation dynamics. Mass loss measurements and infrared thermography were used to quantify evaporation rates. The latter method enables quantification of spatial and temporal variability of salt precipitation to identify its dynamic effects on evaporation. Evaporation from columns filled with texturally-contrasting sand using different salt solutions revealed preferential salt precipitation within the fine textured domains. Salt precipitation reduced evaporation rates from the fine textured regions by nearly an order of magnitude. In contrast, low evaporation rates from coarse-textured regions (due to low capillary drive) exhibited less salt precipitation and consequently less evaporation rate suppression. Experiments provided insights into two new phenomena: (1) a distinct increase in evaporation rate at the onset of evaporation; and (2) a vapor pumping mechanism related to the presence of a salt crust over semidry media. Both phenomena are related to local vapor pressure gradients established between pore water and the surface salt crust. Comparison of two salts: NaCl and NaI, which tend to precipitate above the matrix surface and within matrix pores, respectively, shows a much stronger influence of NaCl on evaporation rate suppression. This disparity reflects the limited effect of NaI precipitation on matrix resistivity for solution and vapor flows.

Nachshon, Uri; Shahraeeni, Ebrahim; Or, Dani; Dragila, Maria; Weisbrod, Noam

2011-12-01

207

Reference evapotranspiration based on Class A pan evaporation via wavelet regression technique  

Microsoft Academic Search

Accurate estimation of reference evapotranspiration (ET0) is important for water resources engineering. Therefore, a large number of empirical or semi-empirical equations have been\\u000a developed for assessing ET0 from numerous meteorological data. However, records of such weather variables are often incomplete or not always available\\u000a for many locations, which is a shortcoming of these complex models. Therefore, practical and simpler methods

Murat Cobaner

208

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

209

[Measurement and estimation methods and research progress of snow evaporation in forests].  

PubMed

Accurate measurement and estimation of snow evaporation (sublimation) in forests is one of the important issues to the understanding of snow surface energy and water balance, and it is also an essential part of regional hydrological and climate models. This paper summarized the measurement and estimation methods of snow evaporation in forests, and made a comprehensive applicability evaluation, including mass-balance methods (snow water equivalent method, comparative measurements of snowfall and through-snowfall, snow evaporation pan, lysimeter, weighing of cut tree, weighing interception on crown, and gamma-ray attenuation technique) and micrometeorological methods (Bowen-ratio energy-balance method, Penman combination equation, aerodynamics method, surface temperature technique and eddy covariance method). Also this paper reviewed the progress of snow evaporation in different forests and its influencal factors. At last, combining the deficiency of past research, an outlook for snow evaporation rearch in forests was presented, hoping to provide a reference for related research in the future. PMID:24697085

Li, Hui-Dong; Guan, De-Xin; Jin, Chang-Jie; Wang, An-Zhi; Yuan, Feng-Hui; Wu, Jia-Bing

2013-12-01

210

Characteristic lengths for evaporation suppression from patchy porous surfaces  

NASA Astrophysics Data System (ADS)

For non-uniformly wet porous surfaces, evaporation rates vary nonlinearly with mean surface water content and with the areal fraction of wet patches. The nonlinearity stems from the complex vapor field forming over individual pores and patches that could enhance vapor fluxes from pores surrounded by dry area (relative to fluxes from the same area of free water surface). The resulting evaporation rates from such a surface are similar to free water surface evaporation despite considerably lower evaporating area (low surface water content). Theoretically, such flux compensation could be suppressed by lumping isolated pores into clusters with equal mean water content. The resulting arrangement in wet patches ensures nearly 1D conditions within the patch and some flux enhancement at the periphery. The interplay between patch water content, patch size, and mean surface water content within a prescribed air flow boundary layer was modeled analytically using single pore diffusion as a building block. Results show existence of a characteristic cluster size that yields the largest evaporation suppression for a given boundary layer thickness and spacing between patches. For patches larger than this size, the relative evaporation rate from patchy surface (relative to free water surface evaporation) reaches a predictable rate equal to the fractional area of clusters. Model predictions for the relation between pore cluster size and evaporation suppression were evaluated numerically and in a series of wind tunnel experiments using porous surfaces with different pore clusters. The findings could be used for the design of optimal porous covers for suppressing evaporation losses from water reservoirs, or for controlling evaporative drying from engineered porous surfaces.

Lehmann, Peter; Or, Dani

2014-05-01

211

Pan-STARRS Moving Object Processing System  

NASA Astrophysics Data System (ADS)

The Institute for Astronomy at the University of Hawaii is developing a large optical astronomical surveying system - the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The Moving Object Processing System (MOPS) client of the Pan-STARRS image processing pipeline is developing software to automatically discover and identify >90% of near-Earth objects (NEOs) 300m in diameter and >80% of other classes of asteroids and comets. In developing its software, MOPS has created a synthetic solar system model (SSM) with over 10 million objects whose distributions of orbital characteristics matches those expected for objects that Pan-STARRS will observe. MOPS verifies its correct operation by simulating the survey and subsequent discovery of synthetically generated objects. MOPS also employs novel techniques in handling the computationally difficult problem of linking large numbers of unknown asteroids in a field of detections. We will describe the creation and verification of the Pan-STARRS MOPS SSM, demonstrate synthetic detections and observations by the MOPS, describe the MOPS asteroid linking techniques, describe accuracy and throughput of the entire MOPS system, and provide predictions regarding the numbers and kinds of objects, including as yet undiscovered "extreme objects", that the MOPS expects to find over its 10-year lifetime. Pan-STARRS is funded under a grant from the U.S. Air Force.

Jedicke, R.; Denneau, L.; Grav, T.; Heasley, J.; Kubica, Jeremy; Pan-STARRS Team

2005-12-01

212

Method of evaporation  

NASA Technical Reports Server (NTRS)

Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly and deploying the droplets in free fall downwardly as a central column within an evacuated column with cool walls. A portion of the solvent evaporates. The vapor flows to the wall, condenses, and usually flows down the wall as a film to condensate collector and drain. The vertical column of freely falling droplets enters the splash guard. The condensate can be collected, sent to other towers or recycled.

Dufresne, Eugene R.

1987-01-01

213

PANs measurements on board theNOAA P-3 during TexAQS-II  

NASA Astrophysics Data System (ADS)

Measurements of peroxycarboxylic nitric anhydrides (PANs, i.e. PAN, PPN, PiBN, APAN, MPAN, and MoPAN) were made using the NCAR PAN-CIGARette chemical ionization mass spectrometer on board the NOAA P-3 aircraft during the 2006 Texas Air Quality Study II (TexAQS-II). In this poster, we present the PANs measurements made during the flight on September 27th as a case study. Two separate plumes from Downtown Houston and the Houston Ship Channel were transported in parallel to the north on that day. The flight track crossed these plumes 8 times at increasing distances downwind, and according to the CO distribution, dilution with surrounding air masses was very slow. These conditions make this very nice case for a pollutant transport and chemistry study. The PAN/PPN ratio increased about 18% as the air mass moved away from the pollution source to the furthest leg which is about 130 km north of downtown Houston. As the photolysis rates for PAN and PPN are similar to each other and the thermal decomposition of PAN is faster than PPN, this ratio change is most likely owing to the difference in the chemistry of the source hydrocarbons for these two PAN species, and indicates a faster depletion of PPN precursors (mainly propanal and 1-butene) as the air masses get older. Also, the relative production of ozone and PANs for the Houston city plume and the ship channel plume are analyzed and compared for this flight, demonstrating the difference in the photochemical processes for urban pollution vs. petroleum industry emissions.

Zheng, W.; Flocke, F. M.; Ryerson, T. B.; Trainer, M. K.; Atlas, E. L.; Schauffler, S.; Donnelly, S.; Holloway, J. S.

2007-12-01

214

Inundation and groundwater dynamics for quantification of evaporative water loss in tropical wetlands  

NASA Astrophysics Data System (ADS)

The remoteness, complexity and heterogeneity of tropical wetlands make the characterisation of their hydrological processes challenging. In particular estimates of evaporative water loss are inherently uncertain. In view of the large influence on the local and regional climate, the quantification of evaporation is essential for the determination of the water balance of permanent and intermittent water bodies. Data for tropical wetlands are scarce where their remoteness impedes direct evaporation measurements. Seasonal inundation dynamics affect evaporation processes in tropical wetlands, which can be analysed in two stages: the first stage during the wet season and the second stage during the dry season. As yet no adequate method exists for determining second stage evaporation without soil moisture data, which are usually unavailable for the remote tropical wetlands. Our study aimed at developing a process-based model to simulate first and second stage evaporation in tropical wetlands. We selected a set of empirical potential evaporation (PET) models of varying complexity, each based on different assumptions and available datasets, and evaluated the models with pan evaporation observations in the Pantanal of South America, one of the largest tropical wetlands in the world. We used high-resolution measurements of surface and groundwater levels at different locations to determine the water available for evaporation. Actual evaporation (AET) was derived by constraining simulated PET based on available water. The model of best fit was applied to different types of water bodies with varying inundation durations and captured first and second stage evaporation. With our new model we could quantify evaporative water loss in the dry and the wet season for different locations in the Pantanal. This new spatially-explicit approach represents an improvement in our understanding of the role of evaporation in the water balance of the Pantanal. We recommend the application of this model in other remote tropical wetlands, since only a minimum of input data is necessary.

Schwerdtfeger, J.; Johnson, M. S.; Couto, E. G.; Amorim, R. S. S.; Sanches, L.; Campelo Jnior, J. H.; Weiler, M.

2014-04-01

215

Evaporation of Liquid Hydrocarbon Mixtures on Titan  

NASA Astrophysics Data System (ADS)

Besides Earth, Titan is the only other known planetary body with proven stable liquids on its surface. The hydrological cycle of these liquid hydrocarbon mixtures is critical in understanding Titans atmosphere and surface features. Evaporation of liquid surface bodies has been indirectly observed as shoreline changes from measurements by Cassini ISS and RADAR (Hayes et al. 2011, Icarus 211, 655-671; Turtle et al. 2011, Science 18, 1414-1417.), but the long seasons of Saturn strongly limit the time span of these observations and their validity over the course of an entire Titan year. Using a novel Titan simulation chamber, the evaporation rate of liquid methane and dissolved nitrogen mixture under Titan surface conditions was derived (Luspay-Kuti et al. 2012, GRL 39, L23203), which is especially applicable to low latitude transient liquids. Polar lakes, though, are expected to be composed of a variety of hydrocarbons, primarily a mixture of ethane and methane (e.g. Cordier et al. 2009, ApJL 707, L128-L131). Here we performed laboratory simulations of ethane-methane mixtures with varying mole fraction under conditions suitable for the polar regions of Titan. We will discuss results specifically addressing the evaporation behavior as the solution becomes increasingly ethane dominated, providing quantitative values for the evaporation rate at every step. These laboratory results are relevant to polar lakes, such as Ontario Lacus, and can shed light on their stability.

Luspay-Kuti, Adrienn; Chevrier, V. F.; Rivera-Valentin, E. G.; Singh, S.; Roe, L. A.; Wagner, A.

2013-10-01

216

Lunar PanCam: Adapting ExoMars PanCam for the ESA Lunar Lander  

NASA Astrophysics Data System (ADS)

A scientific camera system would provide valuable geological context from the surface for lunar lander missions. Here, we describe the PanCam instrument from the ESA ExoMars rover and its possible adaptation for the proposed ESA lunar lander. The scientific objectives of the ESA ExoMars rover are designed to answer several key questions in the search for life on Mars. The ExoMars PanCam instrument will set the geological and morphological context for that mission. We describe the PanCam scientific objectives in geology, and atmospheric science, and 3D vision objectives. We also describe the design of PanCam, which includes a stereo pair of Wide Angle Cameras (WACs), each of which has a filter wheel, and a High Resolution Camera for close up investigations. The cameras are housed in an optical bench (OB) and electrical interface is provided via the PanCam Interface Unit (PIU). Additional hardware items include a PanCam Calibration Target (PCT). We also briefly discuss some PanCam testing during field trials. In addition, we examine how such a 'Lunar PanCam' could be adapted for use on the Lunar surface on the proposed ESA lunar lander.

Coates, A. J.; Griffiths, A. D.; Leff, C. E.; Schmitz, N.; Barnes, D. P.; Josset, J.-L.; Hancock, B. K.; Cousins, C. R.; Jaumann, R.; Crawford, I. A.; Paar, G.; Bauer, A.; the PanCam Team

2012-12-01

217

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\\ Nn, Amable; Lasheras, Juan C.

2009-11-01

218

PanGP: a tool for quickly analyzing bacterial pan-genome profile.  

PubMed

Pan-genome analyses have shed light on the dynamics and evolution of bacterial genome from the point of population. The explosive growth of bacterial genome sequence also brought an extremely big challenge to pan-genome profile analysis. We developed a tool, named PanGP, to complete pan-genome profile analysis for large-scale strains efficiently. PanGP has integrated two sampling algorithms, totally random (TR) and distance guide (DG). The DG algorithm drew sample strain combinations on the basis of genome diversity of bacterial population. The performance of these two algorithms have been evaluated on four bacteria populations with strain numbers varying from 30 to 200, and the DG algorithm exhibited overwhelming advantage on accuracy and stability than the TR algorithm. PMID:24420766

Zhao, Yongbing; Jia, Xinmiao; Yang, Junhui; Ling, Yunchao; Zhang, Zhang; Yu, Jun; Wu, Jiayan; Xiao, Jingfa

2014-05-01

219

Water evaporation and conformational changes from partially solvated ubiquitin.  

PubMed

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. PMID:21188070

Thirumuruganandham, Saravana Prakash; Urbassek, Herbert M

2010-01-01

220

LNA for Low-Power, Low Data Rate PAN Applications  

NASA Astrophysics Data System (ADS)

In this paper a common-gate LNA is presented, which is used in a low-power IEEE 802.15.4 receiver with severer requirements on the current consumption. The LNA is designed in a 0.25 ?m CMOS technology and consumes only 831 ?A. The LNA achieves a voltage gain of 12.89 dB, a NF of 4.86 dB, and an IIP3 of -6.0 dBm.

Stcke, T.; Christoffers, N.; Kokozinski, R.; Kolnsberg, S.; Hosticka, B. J.

2006-09-01

221

An electronic pan/tilt/zoom camera system  

NASA Technical Reports Server (NTRS)

A camera system for omnidirectional image viewing applications that provides pan, tilt, zoom, and rotational orientation within a hemispherical field of view (FOV) using no moving parts was developed. The imaging device is based on the effect that from a fisheye lens, which produces a circular image of an entire hemispherical FOV, can be mathematically corrected using high speed electronic circuitry. An incoming fisheye image from any image acquisition source is captured in memory of the device, a transformation is performed for the viewing region of interest and viewing direction, and a corrected image is output as a video image signal for viewing, recording, or analysis. As a result, this device can accomplish the functions of pan, tilt, rotation, and zoom throughout a hemispherical FOV without the need for any mechanical mechanisms. A programmable transformation processor provides flexible control over viewing situations. Multiple images, each with different image magnifications and pan tilt rotation parameters, can be obtained from a single camera. The image transformation device can provide corrected images at frame rates compatible with RS-170 standard video equipment.

Zimmermann, Steve; Martin, H. Lee

1991-01-01

222

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

223

Experimental investigation of evaporation-induced convection in water using laser based measurement techniques  

Microsoft Academic Search

Recent studies have shown that the evaporation of water can induce surface tension gradients along the water surface that ultimately lead to a surface driven flow, known as Marangoni convection. To visualize and characterize the Marangoni convection in water, this study generated evaporation driven convection in pure water with a vacuum pump to control and increase the evaporation rate of

Xudong Song; David S. Nobes

2011-01-01

224

Optimizing the sound radiation of oil pan based on ANSYS  

Microsoft Academic Search

Based on FEM\\/BEM method, the oil pan models on the finite element and the semi-anechoic chamber boundary element were established. Based on the oil pan models and the engine operating conditions, the oil pan structure had been improved. Using ANSYS software, the oil pan models were optimized, the effect on reducing vibration and sound radiation were predicted by increasing the

Hu Ming-jiang; Qi Li-qiao

2010-01-01

225

Pan-sharpening high spatial resolution ratio images using optimization  

Microsoft Academic Search

Among most of current Pan-sharpening methods, resampling is generally required to make panchromatic (Pan) and multispectral (MS) images matched correctly pixel by pixel. However, few methods have focused on spectral distortions caused by shape distortions of real features during resampling. This paper proposes a new Pan-sharpening algorithm based on the gray and spectral relationships between Pan, MS and the fused

Fangjun Li; Fu Chen; Jianbo Liu

2009-01-01

226

Nanoparticle-mediated evaporation at liquid-vapor interface  

NASA Astrophysics Data System (ADS)

Solution-processed electronic materials for printed electronics frequently take the form of nano-colloidal dispersions of inorganic materials. In standard printing processes, evaporation of the solvent plays a critical role in the deposition of the dispersed nanoparticles. To date, there is no quantitative study of the effects of particles on the interface on the evaporative flux. We provide experimental evidence that nanoparticles present at the interface attenuate evaporation relative to the pure solvent case. To avoid the effects of the complex interfacial shapes attending patterned deposition by printing, we regularize the interface by conducting evaporation experiments in circular-bore cylindrical glass crucibles. The crucible was initially charged with water, and the silica particles were placed on the interface using a modified Langmuir-Blodgett technique. Evaporation rates were measured as a function of surface coverage, contact angle, and surface properties of the nanoparticles.

Fan, Wenxiong

227

Evaporation and skin penetration characteristics of mosquito repellent formulations  

SciTech Connect

Formulations of the mosquito repellent N,N-diethyl-3-methylbenzamide (deet) in combination with a variety of additives were developed to control repellent evaporation and percutaneous penetration. Deet was also formulated with the repellent dimethyl phthalate to study the interaction of the two compounds on the skin. The evaporation and penetration processes were evaluated on whole and split-thickness pig skin using radiolabeled repellents with an in vitro apparatus. Under essentially still air and air flow conditions, one of the deet formulations resulted in significantly reduced total evaporation and percutaneous penetration of deet as compared to unformulated repellent. When deet and dimethyl phthalate were combined, neither repellent affected the total amount of evaporation and penetration of the other compound. However, initial percutaneous penetration and evaporation rates were slightly less and decayed less rapidly than when both chemicals were tested separately at the same dose. These results indicated a degree of competition of the two compounds for the same avenues of loss.

Reifenrath, W.G.; Hawkins, G.S.; Kurtz, M.S.

1989-03-01

228

Structural basis for Pan3 binding to Pan2 and its function in mRNA recruitment and deadenylation.  

PubMed

The conserved eukaryotic Pan2-Pan3 deadenylation complex shortens cytoplasmic mRNA 3' polyA tails to regulate mRNA stability. Although the exonuclease activity resides in Pan2, efficient deadenylation requires Pan3. The mechanistic role of Pan3 is unclear. Here, we show that Pan3 binds RNA directly both through its pseudokinase/C-terminal domain and via an N-terminal zinc finger that binds polyA RNA specifically. In contrast, isolated Pan2 is unable to bind RNA. Pan3 binds to the region of Pan2 that links its N-terminal WD40 domain to the C-terminal part that contains the exonuclease, with a 2:1 stoichiometry. The crystal structure of the Pan2 linker region bound to a Pan3 homodimer shows how the unusual structural asymmetry of the Pan3 dimer is used to form an extensive high-affinity interaction. This binding allows Pan3 to supply Pan2 with substrate polyA RNA, facilitating efficient mRNA deadenylation by the intact Pan2-Pan3 complex. PMID:24872509

Wolf, Jana; Valkov, Eugene; Allen, Mark D; Meineke, Birthe; Gordiyenko, Yuliya; McLaughlin, Stephen H; Olsen, Tayla M; Robinson, Carol V; Bycroft, Mark; Stewart, Murray; Passmore, Lori A

2014-07-17

229

3 CFR 8236 - Proclamation 8236 of April 10, 2008. Pan American Day and Pan American Week, 2008  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Proclamation 8236 of April 10, 2008. Pan American Day and Pan American Week, 2008 8236 Proclamation 8236 Presidential...Proclamation 8236 of April 10, 2008 Proc. 8236 Pan American Day and Pan American Week, 2008By the...

2009-01-01

230

THE Pan-STARRS1 PHOTOMETRIC SYSTEM  

SciTech Connect

The Pan-STARRS1 survey is collecting multi-epoch, multi-color observations of the sky north of declination -30 Degree-Sign to unprecedented depths. These data are being photometrically and astrometrically calibrated and will serve as a reference for many other purposes. In this paper, we present our determination of the Pan-STARRS1 photometric system: g{sub P1}, r{sub P1}, i{sub P1}, z{sub P1}, y{sub P1}, and w{sub P1}. The Pan-STARRS1 photometric system is fundamentally based on the Hubble Space Telescope Calspec spectrophotometric observations, which in turn are fundamentally based on models of white dwarf atmospheres. We define the Pan-STARRS1 magnitude system and describe in detail our measurement of the system passbands, including both the instrumental sensitivity and atmospheric transmission functions. By-products, including transformations to other photometric systems, Galactic extinction, and stellar locus, are also provided. We close with a discussion of remaining systematic errors.

Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Morgan, J. S.; Wainscoat, R. J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Stubbs, C. W.; Shivvers, I. S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lykke, K. R. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States); Doherty, P. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2012-05-10

231

Imitation in Neonatal Chimpanzees ("Pan Troglodytes")  

ERIC Educational Resources Information Center

This paper provides evidence for imitative abilities in neonatal chimpanzees ("Pan troglodytes"), our closest relatives. Two chimpanzees were reared from birth by their biological mothers. At less than 7 days of age the chimpanzees could discriminate between, and imitate, human facial gestures (tongue protrusion and mouth opening). By the time

Myowa-Yamakoshi, Masako; Tomonaga, Masaki; Tanaka, Masayuki; Matsuzawa, Tetsuro

2004-01-01

232

Numerical competence in a chimpanzee (Pan troglodytes)  

Microsoft Academic Search

A chimpanzee (Pan troglodytes), trained to count foods and objects by using Arabic numbers, demonstrated the ability to sum arrays of 0-4 food items placed in 2 of 3 possible sites. To address representational use of numbers, we next baited sites with Arabic numbers as stimuli. In both cases performance was significantly above chance from the first sessions, which suggests

Sarah T. Boysen; Gary G. Berntson

1989-01-01

233

Controllable evaporation of cesium from a dispenser oven  

NASA Astrophysics Data System (ADS)

This instrument allows controlled evaporation of the alkali metal cesium over a wide range of evaporation rates. The oven has three unique features. The first is an alkali metal reservoir that uses a dispenser as a cesium source. The heating current of the dispenser controls the evaporation rate allowing generation of an adjustable and stable flow of pure cesium. The second is a blocking valve, which is fully metallic as is the body of the oven. This construction both reduces contamination of the dispenser and enables the oven to be operated up to 300 C, with only small temperature variations (<5 C). By minimizing the temperature variation, the built up of the alkali metal at a cold spot is significantly hindered. The last feature is an integral surface ionization detector for measuring and controlling the evaporation rate. The dispenser oven can be easily transferred to the other alkali-metals.

Fantz, U.; Friedl, R.; Frschle, M.

2012-12-01

234

Controllable evaporation of cesium from a dispenser oven.  

PubMed

This instrument allows controlled evaporation of the alkali metal cesium over a wide range of evaporation rates. The oven has three unique features. The first is an alkali metal reservoir that uses a dispenser as a cesium source. The heating current of the dispenser controls the evaporation rate allowing generation of an adjustable and stable flow of pure cesium. The second is a blocking valve, which is fully metallic as is the body of the oven. This construction both reduces contamination of the dispenser and enables the oven to be operated up to 300 C, with only small temperature variations (<5 C). By minimizing the temperature variation, the built up of the alkali metal at a cold spot is significantly hindered. The last feature is an integral surface ionization detector for measuring and controlling the evaporation rate. The dispenser oven can be easily transferred to the other alkali-metals. PMID:23277980

Fantz, U; Friedl, R; Frschle, M

2012-12-01

235

Characterization of lithium evaporators for LTX  

NASA Astrophysics Data System (ADS)

The presence of lithium on the internal components of fusion devices has proven to be beneficial for reactor performance. The Lithium Tokamak Experiment (LTX) will be the first experimental fusion device operating with a significant portion of its internal surface coated with lithium. One of the key capabilities in the device is the reliable production of lithium films inside the reactor. This task is accomplished with the use of lithium evaporators, specially designed for LTX using resistively heated yttria crucibles. In the present work, results from the operation of one of these evaporators on a separate test stand are presented. Deposition measurements at different power levels were performed using a quartz crystal deposition monitor, and temperature distributions in the evaporator crucible and its content were obtained using an infrared camera and a dip-in thermocouple probe. Modeling of the evaporation cloud was done with the raytracing software OptiCAD, and comparisons between the computations and the temperature and flux measurements were performed, in order to accurately predict spatial lithium deposition rates in different locations of the LTX device.

Nieto-Perez, M.; Majeski, R.; Timberlake, J.; Lundberg, D.; Kaita, R.; Arevalo-Torres, B.

2010-11-01

236

Multilayer composite material and method for evaporative cooling  

NASA Technical Reports Server (NTRS)

A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.

Buckley, Theresa M. (Inventor)

2002-01-01

237

Advances in Sensible Heat Balance Characterization of Soil Water Evaporation  

NASA Astrophysics Data System (ADS)

Soil water evaporation intimately couples the hydrological cycle with the land-surface energy balance, making it an important driver for a wide range of terrestrial processes. To date, few methods have been available characterize soil water evaporation in detail, which has, in turn, limited capability to predict soil water evaporation processes in local and large scale models. Recent work has developed a measurement-based soil sensible heat balance (SHB) approach, capable of quantifying evaporation time and depth dynamics at a vertical scale of millimeters, near the soil surface. The SHB approach does not require detailed characterization or estimation of soil hydraulic properties, which has been a limitation in previous work. Rather it utilizes detailed measurements of the soil temperature profile and soil thermal properties from heat-pulse sensors in order to derive evaporation front dynamics. Laboratory experiments indicate that the SHB approach is precise to within <10% of independent mass balance measurements. Field tests indicate that the SHB is well correlated to lysimeter and Bowen ratio measurement approaches for bare surface conditions. Using SHB, laboratory and field experiments have characterized migration of the soil water evaporation front during multi-day drying events, and linked the shift between potential evaporation and falling rate evaporation to changes in soil surface albedo and soil moisture.

Heitman, J.; Xiao, X.; Deol, P. K.; Horton, R.; Ren, T.

2013-05-01

238

Small Scale Evaporation Kinetics of a Binary Fluid Mixture  

NASA Astrophysics Data System (ADS)

Evaporation induces a concentrating effect in liquid mixtures. The transient process has significant influence on the dynamic behaviors of a complex fluid. To simultaneously investigate the fluid properties and small-scale evaporation kinetics during the transient process, the quartz crystal microbalance is applied to a binary mixture droplet of light alcohols including both a single volatile component (a fast evaporation followed by a slow evaporation) and a mixture of two volatile components with comparable evaporation rates. The density and viscosity stratification are evaluated by the shear wave, and the evaporation kinetics is measured by the resonant signature of the acoustic p-wave. The evaporation flux can be precisely determined by the resonant frequency spikes and the complex impedance. To predict the concentration field, the moving interface, and the precision evaporation kinetics of the mixture, a multiphase model is developed to interpret the complex impedance signals based on the underlying mass and momentum transport phenomena. The experimental method and theoretical model are developed for better characterizing and understanding of the drying process involving liquid mixtures of protein pharmaceuticals.

Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi

2013-03-01

239

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

2012-08-01

240

Droplet evaporation on heated hydrophobic and superhydrophobic surfaces.  

PubMed

The evaporation characteristics of sessile water droplets on smooth hydrophobic and structured superhydrophobic heated surfaces are experimentally investigated. Droplets placed on the hierarchical superhydrophobic surface subtend a very high contact angle (?160) and demonstrate low roll-off angle (?1), while the hydrophobic substrate supports corresponding values of 120 and ?10. The substrates are heated to different constant temperatures in the range of 40-60?C, which causes the droplet to evaporate much faster than in the case of natural evaporation without heating. The geometric parameters of the droplet, such as contact angle, contact radius, and volume evolution over time, are experimentally tracked. The droplets are observed to evaporate primarily in a constant-contact-angle mode where the contact line slides along the surface. The measurements are compared with predictions from a model based on diffusion of vapor into the ambient that assumes isothermal conditions. This vapor-diffusion-only model captures the qualitative evaporation characteristics on both test substrates, but reasonable quantitative agreement is achieved only for the hydrophobic surface. The superhydrophobic surface demonstrates significant deviation between the measured evaporation rate and that obtained using the vapor-diffusion-only model, with the difference being amplified as the substrate temperature is increased. A simple model considering thermal diffusion through the droplet is used to highlight the important role of evaporative cooling at the droplet interface in determining the droplet evaporation characteristics on superhydrophobic surfaces. PMID:24827255

Dash, Susmita; Garimella, Suresh V

2014-04-01

241

Contaminated Water Evaporation System Design for the Tailing Facility  

NASA Astrophysics Data System (ADS)

The treatment and disposal of contaminated water is a major issue for the mining industry. A common approach to this issue is through the process of evaporation and evapotranspiration. This process is commonly done simply by spreading the contaminated water over a given area and exposing it to the sun. This causes the water to evaporate and be returned into the hydrological cycle as clean water, leaving the contaminants behind. Evaporation systems are based on the continuity principle for conservation of mass, so that the rate of evaporation is greater than the inflow. Evaporation systems are by no means a new method, but the design criteria, procedures, and methodology have not been documented. Without design criteria there are no guidelines to creating a successful evaporation system for water treatment. This paper describes the methodology of designing a water evaporation system based on the continuity principle and conservation of mass. This paper also presents how incorporating a time series model can utilize historical data to predict future requirements for the evaporation area and contaminated water storage. With this methodology, the mining industry can have guidelines and design standards to follow for a sustainable alternative for the treatment of contaminated water.; ;

Langer, J. M.; Cheng, J.

2012-12-01

242

Divergent roles for maize PAN1 and PAN2 receptor-like proteins in cytokinesis and cell morphogenesis.  

PubMed

Pangloss1 (PAN1) and PAN2 are leucine-rich repeat receptor-like proteins that function cooperatively to polarize the divisions of subsidiary mother cells (SMCs) during stomatal development in maize (Zea mays). PANs colocalize in SMCs, and both PAN1 and PAN2 promote polarization of the actin cytoskeleton and nuclei in these cells. Here, we show that PAN1 and PAN2 have additional functions that are unequal or divergent. PAN1, but not PAN2, is localized to cell plates in all classes of dividing cells examined. pan1 mutants exhibited no defects in cell plate formation or in the recruitment or removal of a variety of cell plate components; thus, they did not demonstrate a function for PAN1 in cytokinesis. PAN2, in turn, plays a greater role than PAN1 in directing patterns of postmitotic cell expansion that determine the shapes of mature stomatal subsidiary cells and interstomatal cells. Localization studies indicate that PAN2 impacts subsidiary cell shape indirectly by stimulating localized cortical actin accumulation and polarized growth in interstomatal cells. Localization of PAN1, Rho of Plants2, and PIN1a suggests that PAN2-dependent cell shape changes do not involve any of these proteins, indicating that PAN2 function is linked to actin polymerization by a different mechanism in interstomatal cells compared with SMCs. Together, these results demonstrate that PAN1 and PAN2 are not dedicated to SMC polarization but instead play broader roles in plant development. We speculate that PANs may function in all contexts to regulate polarized membrane trafficking either directly or indirectly via their influence on actin polymerization. PMID:24578508

Sutimantanapi, Dena; Pater, Dianne; Smith, Laurie G

2014-04-01

243

Evaporative Cooling of Sodium Atoms  

Microsoft Academic Search

Results of experiments on evaporative cooling of sodium atoms are presented. Atoms are loaded into a spherical quadrupole magnetic trap and are cooled by a novel technique, rf induced evaporation. The elastic collision cross section for cold sodium atoms is measured to be 6 10^{-12} cm^2 . These initial experiments result in an increase of phase space density of 190.

Kendall Bruce Davis

1995-01-01

244

Black hole evaporation: a paradigm  

Microsoft Academic Search

A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing

Abhay Ashtekar; Martin Bojowald

2005-01-01

245

Vacuum flash evaporated polymer composites  

DOEpatents

A method for fabrication of polymer composite layers in a vacuum is disclosed. More specifically, the method of dissolving salts in a monomer solution, vacuum flash evaporating the solution, condensing the flash evaporated solution as a liquid film, and forming the condensed liquid film into a polymer composite layer on a substrate is disclosed.

Affinito, J.D.; Gross, M.E.

1997-10-28

246

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

247

The Missing Link in Coenzyme A Biosynthesis: PanM (formerly YhhK), a Yeast GCN5 Acetyltransferase Homolog Triggers Aspartate Decarboxylase (PanD) Maturation in Salmonella enterica  

PubMed Central

Summary Coenzyme A (CoA) is an essential cofactor for all forms of life. The biochemistry underpinning the assembly of CoA in Escherichia coli and other enterobacteria is well understood, except for the events leading to maturation of the L-aspartate-?-decarboxylase (PanD) enzyme that converts pantothenate to ?-alanine. PanD is synthesized as pro-PanD, which undergoes an auto-proteolytic cleavage at residue Ser25 to yield the catalytic pyruvoyl moiety of the enzyme. Since 1990, it has been known that Escherichia coli yhhK strains are pantothenate auxotrophs, but the role of YhhK in pantothenate biosynthesis remained an enigma. Here we show that Salmonella enterica yhhK strains are also pantothenate auxotrophs. In vivo and in vitro evidence show that YhhK interacts directly with PanD, and that such interactions accelerate pro-PanD maturation. We also show that S. enterica yhhK strains accumulate pro-PanD,and that not all pro-PanD proteins require YhhK for maturation. For example, the Corynebacterium glutamicum panD+ gene corrected the pantothenate auxtrophy of a S. enterica yhhK strain, supporting in vitro evidence obtained by others that some pro-PanD proteins autocleave at faster rates. We propose the name PanM for YhhK to reflect its role as a trigger of pro-PanD maturation by stabilizing pro-PanD in an autocleavage-prone conformation.

Stuecker, Tara N.; Hodge, Kelsey M.; Escalante-Semerena, Jorge C.

2012-01-01

248

A stochastic assessment of climate change impacts on precipitation and potential evaporation in Alberta  

NASA Astrophysics Data System (ADS)

In many climate change investigations, changes in precipitation are projected under various scenarios; however, changes in evaporation have received relatively less attention. For irrigation and water resources management, the difference between potential evaporation and precipitation can provide better quantification of local water availability and drought conditions. Therefore, projecting joint variations in precipitation and potential evaporation can provide better information for climate change adaptation. A stochastic approach based on a Generalised Linear Model (GLM) framework is proposed to study these together at a station scale. Eight stations in Alberta are selected for which historical pan evaporation records and up-to-date meteorological information are available. Results show that potential evaporation estimated from Global Circulation Models directly can be unreliable. The evaporation ensemble simulated by the GLM approach can represent observed evaporation more realistically and provide better uncertainty quantification. If only simulated precipitation is considered, the projected drought conditions in the 2080s are likely to be less severe than that in the 2000s. However, the projected difference between precipitation and evaporation (water deficit) shows that the future drought conditions may be higher or lower, varying between the stations. Implications of the results and further development of the proposed approach to address spatial dependence between stations are also discussed.

Vashchyshyn, I.; Wheater, H. S.; Chun, K.

2012-12-01

249

Evaporation-driven instability of the precorneal tear film.  

PubMed

Tear-film instability is widely believed to be a signature of eye health. When an interblink is prolonged, randomly distributed ruptures occur in the tear film. "Black spots" and/or "black streaks" appear in 15 to 40 s for normal individuals. For people who suffer from dry eye, tear-film breakup time (BUT) is typically less than a few seconds. To date, however, there is no satisfactory quantitative explanation for the origin of tear rupture. Recently, it was proposed that tear-film breakup is related to locally high evaporative thinning. A spatial variation in the thickness of the tear-film lipid layer (TFLL) may lead to locally elevated evaporation and subsequent tear-film breakup. We examine the local-evaporation-driven tear-film-rupture hypothesis in a one-dimensional (1-D) model for the evolution of a thin aqueous tear film overriding the cornea subject to locally elevated evaporation at its anterior surface and osmotic water influx at its posterior surface. Evaporation rate depends on mass transfer both through the coating lipid layer and through ambient air. We establish that evaporation-driven tear-film breakup can occur under normal conditions but only for higher aqueous evaporation rates. Predicted roles of environmental conditions, such as wind speed and relative humidity, on tear-film stability agree with clinical observations. More importantly, locally elevated evaporation leads to hyperosmolar spots in the tear film and, hence, vulnerability to epithelial irritation. In addition to evaporation rate, tear-film instability depends on the strength of healing flow from the neighboring region outside the breakup region, which is determined by the surface tension at the tear-film surface and by the repulsive thin-film disjoining pressure. This study provides a physically consistent and quantitative explanation for the formation of black streaks and spots in the human tear film during an interblink. PMID:23842140

Peng, Cheng-Chun; Cerretani, Colin; Braun, Richard J; Radke, C J

2014-04-01

250

The desorptivity model of bulk soil-water evaporation  

NASA Technical Reports Server (NTRS)

Available models of bulk evaporation from a bare-surfaced soil are difficult to apply to field conditions where evaporation is complicated by two main factors: rate-limiting climatic conditions and redistribution of soil moisture following infiltration. Both factors are included in the "desorptivity model', wherein the evaporation rate during the second stage (the soil-limiting stage) of evaporation is related to the desorptivity parameter, A. Analytical approximations for A are presented. The approximations are independent of the surface soil moisture. However, calculations using the approximations indicate that both soil texture and soil moisture content at depth significantly affect A. Because the moisture content at depth decreases in time during redistribution, it follows that the A parameter also changes with time. Consequently, a method to calculate a representative value of A was developed. When applied to field data, the desorptivity model estimated cumulative evaporation well. The model is easy to calculate, but its usefulness is limited because it requires an independent estimate of the time of transition between the first and second stages of evaporation. The model shows that bulk evaporation after the transition to the second stage is largely independent of climatic conditions.

Clapp, R. B.

1983-01-01

251

The Evaporative Function of Cockroach Hygroreceptors  

PubMed Central

Insect hygroreceptors associate as antagonistic pairs of a moist cell and a dry cell together with a cold cell in small cuticular sensilla on the antennae. The mechanisms by which the atmospheric humidity stimulates the hygroreceptive cells remain elusive. Three models for humidity transduction have been proposed in which hygroreceptors operate either as mechanical hygrometers, evaporation detectors or psychrometers. Mechanical hygrometers are assumed to respond to the relative humidity, evaporation detectors to the saturation deficit and psychrometers to the temperature depression (the difference between wet-bulb and dry-bulb temperatures). The models refer to different ways of expressing humidity. This also means, however, that at different temperatures these different types of hygroreceptors indicate very different humidity conditions. The present study tested the adequacy of the three models on the cockroachs moist and dry cells by determining whether the specific predictions about the temperature-dependence of the humidity responses are indeed observed. While in previous studies stimulation consisted of rapid step-like humidity changes, here we changed humidity slowly and continuously up and down in a sinusoidal fashion. The low rates of change made it possible to measure instantaneous humidity values based on UV-absorption and to assign these values to the hygroreceptive sensillum. The moist cell fitted neither the mechanical hygrometer nor the evaporation detector model: the temperature dependence of its humidity responses could not be attributed to relative humidity or to saturation deficit, respectively. The psychrometer model, however, was verified by the close relationships of the moist cells response with the wet-bulb temperature and the dry cells response with the dry-bulb temperature. Thus, the hygroreceptors respond to evaporation and the resulting cooling due to the wetness or dryness of the air. The drier the ambient air (absolutely) and the higher the temperature, the greater the evaporative temperature depression and the power to desiccate.

Tichy, Harald; Kallina, Wolfgang

2013-01-01

252

The evaporative function of cockroach hygroreceptors.  

PubMed

Insect hygroreceptors associate as antagonistic pairs of a moist cell and a dry cell together with a cold cell in small cuticular sensilla on the antennae. The mechanisms by which the atmospheric humidity stimulates the hygroreceptive cells remain elusive. Three models for humidity transduction have been proposed in which hygroreceptors operate either as mechanical hygrometers, evaporation detectors or psychrometers. Mechanical hygrometers are assumed to respond to the relative humidity, evaporation detectors to the saturation deficit and psychrometers to the temperature depression (the difference between wet-bulb and dry-bulb temperatures). The models refer to different ways of expressing humidity. This also means, however, that at different temperatures these different types of hygroreceptors indicate very different humidity conditions. The present study tested the adequacy of the three models on the cockroach's moist and dry cells by determining whether the specific predictions about the temperature-dependence of the humidity responses are indeed observed. While in previous studies stimulation consisted of rapid step-like humidity changes, here we changed humidity slowly and continuously up and down in a sinusoidal fashion. The low rates of change made it possible to measure instantaneous humidity values based on UV-absorption and to assign these values to the hygroreceptive sensillum. The moist cell fitted neither the mechanical hygrometer nor the evaporation detector model: the temperature dependence of its humidity responses could not be attributed to relative humidity or to saturation deficit, respectively. The psychrometer model, however, was verified by the close relationships of the moist cell's response with the wet-bulb temperature and the dry cell's response with the dry-bulb temperature. Thus, the hygroreceptors respond to evaporation and the resulting cooling due to the wetness or dryness of the air. The drier the ambient air (absolutely) and the higher the temperature, the greater the evaporative temperature depression and the power to desiccate. PMID:23342058

Tichy, Harald; Kallina, Wolfgang

2013-01-01

253

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.

Menking, Kirsten M.; Anderson, Roger Y.; Brunsell, Nathaniel A.; Allen, Bruce D.; Ellwein, Amy L.; Loveland, Thomas A.; Hostetler, Steven W.

2000-01-01

254

Laser induced fluorescence of barium evaporating from a dispenser cathode  

NASA Astrophysics Data System (ADS)

A continuous wave dye laser is used to induce resonance fluorescence in Ba atoms evaporating from a thermionic dispenser cathode. The laser is tuned to the 553.5 microns Ba I line by making use of the optogalvanic effect in a hollow cathode discharge tube. Photon counting equipment is used to measure the Ba fluorescent intensity as a function of cathode temperature and laser power. Ba concentrations and evaporation rates as functions of temperature are derived from the fluorescent intensity. Laser induced fluorescence is established as a technique for examining various species evaporating from cathodes. The technique can be used in attempts to determine cathode failure mechanisms.

Zemyan, S. M.

1982-03-01

255

Evaporation of iron during steelmaking in arc furnaces  

NASA Astrophysics Data System (ADS)

The problems of iron evaporation during steelmaking in an arc steel-melting furnace are considered. A procedure is developed for the calculation of the specific iron evaporation rate and the heat losses during evaporation. More complete absorption of the heat of condensation by a charge and the oxidation of iron vapors are shown to be promoted by the following factors: the presence of a slag coating, a decrease in the well diameter, an increase in the well depth, an increase in the electrode failure diameter, and directional supply of an oxidizer to the near-electrode zone.

Karasev, V. P.; Sutyagin, K. L.

2009-12-01

256

Externally Induced Evaporation of Young Stellar Disks in Orion  

NASA Technical Reports Server (NTRS)

In this paper we propose a model for the evaporation of disks around young low-mass stars by external sources of high energy photons. Two evaporation techniques are possible. Lyman continuum radiation can ionize hydrogen at the disk surface powering a steady thermal ionized disk-wind, or FUV radiation can heat the disk through photo-electric grain processes powering a slower thermal neutral disk-wind. Applying these two models to the evaporating objects in the Trapezium produces a satisfactory solution to both the mass-loss rate and size of the ionized envelopes.

Johnstone, D.; Hollenbach, D.; Shu, F.

1996-01-01

257

Evaporative roof cooling system  

SciTech Connect

An evaporative roof cooling system is described for placement upon a roof surface exposed to relatively high levels of solar radiation causing high under roof temperatures and comprising: (a) water distribution mist/spray nozzles positioned on the roof surface for supplying substantially uniform mist/sprays of water to lay down a substantially uniform thin film of water on the roof surface; (b) conduit means on the one roof surface for supplying the nozzles with water; (c) solenoid-controlled valve means in water flow communication with the conduit means to supply controlled quantities of water to the nozzles through the conduit means over periods during which the temperature of the roof surface is measured to be within a predetermined temperature range; (d) temperature measurement means comprised of a thermistor encapsulated in an epoxy block in direct contact with the roof surface for monitoring and measuring the actual temperature of the surface substantially by thermal conductivity and developing an electrical resistance value in direct relationship with the temperature of the surface; and (e) cooling system control means in electric communication with the temperature measurement means for comparing the electric resistance value developed by the temperature measurement means and a range of current values related to the predetermined temperature range.

Viner, S.G.

1988-08-09

258

Kinetic approach to the evaporation and condensation problem  

NASA Technical Reports Server (NTRS)

In the paper, the Boltzmann equation governing the evaporation and condensation phenomena is solved by the Monte Carlo method. Based on the kinetic theory of gas the role of the non-equilibrium Knudsen layer and the growth of the hydrodynamic region outside the layer as time proceeds are simulated. Results show two possible types of transient developments in the vapor phase. The effects of the molecular absorption coefficient of the phase surface are examined. Except in the case of very strong evaporation the kinematic effects of binary collisions among vapor molecules on the mass flux rate are not serious. The limiting case of the quasi-steady evaporation and the maximal value of the evaporation rate are obtained.

Murakami, M.; Oshima, K.

1974-01-01

259

BRDF of Salt Pan Regolith Samples  

NASA Technical Reports Server (NTRS)

Laboratory Bi-directional Reflectance Distribution Function (BRDF) measurements of salt pan regolith samples are presented in this study in an effort to understand the role of spatial and spectral variability of the natural biome. The samples were obtained from Etosha Pan, Namibia (19.20 deg S, 15.93 deg E, alt. 1100 m). It is shown how the BRDF depends on the measurement geometry - incident and scatter angles and on the sample particle sizes. As a demonstration of the application of the results, airborne BRDF measurements acquires with NASA's Cloud Absorption Radiometer (CAR) over the same general site where the regolith samples were collected are compared with the laboratory results. Good agreement between laboratory measured and field measured BRDF is reported.

Georgiev, Georgi T.; Gatebe, Charles K.; Butler, James J.; King, Michael D.

2008-01-01

260

ENSO and multi-decadal 'trends' in continental evaporation  

NASA Astrophysics Data System (ADS)

While the hydrological cycle is expected to intensify in response to global warming, little unequivocal evidence of such an acceleration has yet been found on a global scale. This holds in particular for terrestrial evaporation, the crucial return flow of water from continents to atmosphere. Counterintuitively, the few studies that have applied satellite and in situ observations to evaluate multi-decadal trends have uncovered prolonged declines in global average continental evaporation. A priori, these reductions contradict the expectations of an intensifying water cycle. Up to date, the question of whether these declines in evaporation reflect a more permanent feature of global warming or they result from internal climate variability, has been left unanswered. Here, we attempt to answer that question by analyzing global satellite-based datasets of evaporative fluxes, soil moisture and NDVI. Our findings reveal that the reported recent declines in global continental evaporation are not a consequence of a persistent reorganization of the water cycle, but a consequence of internal climate variability. During El Nio, limitations in the supply of moisture in central Australia, southern Africa and eastern South America cause vegetation water-stress and reduced terrestrial evaporation. These regional terrestrial evaporation declines are so pronounced that that determine the total annual volumes of water vapour from continental land surfaces into the atmosphere. Meanwhile, in northern latitudes (where the effects of ENSO are weaker) continental evaporation has raised since the '80s at rates that are consistent with the expectations calculated from air temperature trends. Future changes in continental evaporation will be determined by the response of ENSO to changes in global radiative forcing, which still remains highly uncertain. Opportunely, the increasing timespan of satellite observation records will enable a more significant assessment of the trends in global evaporation in coming years.

Miralles, Diego; Teuling, Ryan; van den Berg, Martinus; Gash, John; Parinussa, Robert; De Jeu, Richard; Beck, Hylke; Holmes, Thomas; Jimnez, Carlos; Verhoest, Niko; Dorigo, Wouter; Dolman, Han

2014-05-01

261

The structure of the Pan2-Pan3 core complex reveals cross-talk between deadenylase and pseudokinase.  

PubMed

Pan2-Pan3 is a conserved complex involved in the shortening of mRNA poly(A) tails, the initial step in eukaryotic mRNA turnover. We show that recombinant Saccharomyces cerevisiae Pan2-Pan3 can deadenylate RNAs in vitro without needing the poly(A)-binding protein Pab1. The crystal structure of an active ~200-kDa core complex reveals that Pan2 and Pan3 interact with an unusual 1:2 stoichiometry imparted by the asymmetric nature of the Pan3 homodimer. An extended region of Pan2 wraps around Pan3 and provides a major anchoring point for complex assembly. A Pan2 module formed by the pseudoubiquitin-hydrolase and RNase domains latches onto the Pan3 pseudokinase with intertwined interactions that orient the deadenylase active site toward the A-binding site of the interacting Pan3. The molecular architecture of Pan2-Pan3 suggests how the nuclease and its pseudokinase regulator act in synergy to promote deadenylation. PMID:24880344

Schfer, Ingmar B; Rode, Michaela; Bonneau, Fabien; Schssler, Steffen; Conti, Elena

2014-07-01

262

Computations of turbulent evaporating sprays  

NASA Technical Reports Server (NTRS)

A computational study of turbulent evaporating sprays is reported. The major focus is to examine the sensitivity of the vaporization behavior of turbulent sprays to the transient liquid-phase processes. Three models considered to represent these processes are the thin skin, infinite diffusion, and diffusion limit models. Favre-averaged equations with k-epsilon-g turbulence model are employed for the gas phase. The Lagrangian approach with a stochastic separated flow method is used for the liquid phase where the effects of gas turbulence on droplet trajectories and interphase transport rates are considered using random-walk computations. Also the variable-property effects are considered in detail. Results indicate that, depending upon the boiling temperature and heat of vaporization of the fuel considered, the vaporization behavior of turbulent sprays may be quite sensitive to the modeling of transient liquid-phase processes. Thus, it is important that for most hydrocarbon fuels these processes be adequately represented in any comprehensive spray computations. The present results also provide further support to the conclusions of earlier studies which have been based on simplified spray configurations.

Aggarwal, S. K.; Chitre, S.

1989-01-01

263

Evaporative cooling of flare plasma  

NASA Technical Reports Server (NTRS)

A one-dimensional loop model for the evaporative cooling of the coronal flare plasma was investigated. Conductive losses dominated radiative cooling, and the evaporative velocities were small compared to the sound speed. The profile and evolution of the temperature were calculated. The model was in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation was to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

Antiochos, S. K.; Sturrock, P. A.

1976-01-01

264

Evaporative cooling of flare plasma  

NASA Technical Reports Server (NTRS)

We investigate a one-dimensional loop model for the evaporative cooling of the coronal flare plasma. The important assumptions are that conductive losses dominate radiative cooling and that the evaporative velocities are small compared with the sound speed. We calculate the profile and evolution of the temperature and verify the accuracy of our assumptions for plasma parameters typical of flare regions. The model is in agreement with soft X-ray observations on the evolution of flare temperatures and emission measures. The effect of evaporation is to greatly reduce the conductive heat flux into the chromosphere and to enhance the EUV emission from the coronal flare plasma.

Antiochos, S. K.; Sturrock, P. A.

1978-01-01

265

Production of stable tellurium evaporated targets  

NASA Astrophysics Data System (ADS)

Due to the low melting point of tellurium metal, self-supporting Te targets degrade quickly when exposed to particle beams. This situation is greatly improved if the tellurium material is evaporated onto C foil backings. Elastic scattering in target and backing layers broadens the Te peak, making measurements difficult, while too little material reduces the reaction rate. Therefore, it is necessary to optimize the target thickness. Evaporated metallic and oxide Te targets were prepared at Argonne National Laboratory by vacuum deposition from a resistively heated source boat. The stability of the targets was then tested by exposing them to a varying intensity alpha beam with an energy range from 17 to 27 MeV using the FN Tandem Van de Graaff accelerator at the University of Notre Dame. Optimal target thicknesses and beam currents were then obtained for p-process experiments. A description of the apparatus and production method will be presented.

Greene, John P.; Palumbo, Annalia; Tan, Wanpeng; Grres, Joachim; Wiescher, Michael C.

2008-06-01

266

Coupling dynamic blow down and pool evaporation model for LNG.  

PubMed

Treating the dynamic effects of accidental discharges of liquefied natural gas (LNG) is important for realistic predictions of pool radius. Two phenomena have important influence on pool spread dynamics, time-varying discharge (blow down) and pool ignition. Time-varying discharge occurs because a punctured LNG tanker or storage tank drains with a decreasing liquid head and decreasing head-space pressure. Pool ignition increases the evaporation rate of a pool and consequently decreases the ultimate pool area. This paper describes an approach to treat these phenomena in a dynamic pool evaporation model. The pool evaporation model developed here has two separate regimes. Early in the spill, momentum forces dominate and the pool spreads independently of pool evaporation rate and the corresponding heat transfer rate. After the average pool depth drops below a minimum value, momentum forces are largely dissipated and the thin edges of the pool completely evaporate, so pool area is established by the heat transfer rate. The maximum extent of a burning pool is predicted to be significantly less than that of an unignited pool because the duration of the first regime is reduced by higher heat transfer rates. The maximum extent of an LNG pool is predicted to be larger upon accounting for blow down compared with using a constant average discharge rate. However, the maximum pool extent occurs only momentarily before retreating. PMID:17184912

Woodward, John L

2007-02-20

267

On the inherent asymmetric nature of the complementary relationship of evaporation  

NASA Astrophysics Data System (ADS)

New theoretical considerations indicate that the complementary relationship (CR) of evaporation is inherently asymmetric when the time rate of change between actual and apparent potential evaporations is considered. The theory also estimates the extent of this asymmetry as a function of the surface temperature and predicts that a symmetric CR, independent of the surface temperature, can only be expected when no energy exchange between the source of the apparent potential evaporation process and its surroundings occurs, a rather unrealistic situation. The derived asymmetric CR is employed for operational evaporation estimations. The parameters of the proposed practical evaporation estimation model are from the Priestley-Taylor and Penman equations.

Szilagyi, Jozsef

2007-01-01

268

Marangoni instability induced convection in an evaporating liquid droplet  

NASA Technical Reports Server (NTRS)

The processes occurring when a liquid drop undergoes evaporation are described. When a liquid drop undergoes evaporation, its surface temperature decreases. If the droplet is free floating in a microgravity environment, the heat transfer process inside the droplet is initially condition controlled. As the process continues, a radial temperature gradient builds up at the free surface until the critical Marangoni number is exceeded. Then the onset of instability induces thermocapillary convective flows, which in turn speed up the evaporation. The convective flows will subside when the interior of the droplet reaches a certain equilibrium temperature, and the process will return to the diffusion controlled mode. Both preliminary modeling and recent laboratory data have confirmed that Marangoni instability induced convection can and does occur in the droplet evaporation process. Mathematical models representing Marangoni instability in an evaporating liquid drop are presented. An ideal space experiment to study and characterize the onset of Marangoni instability in an evaporating liquid droplet and to establish the effect of Marangoni instability induced convection on the droplet evaporation rate is outlined and the need for conducting such experiments in space is highlighted. However, before an opportunity to conduct experiments in space arises, ground based experiments have to be conducted to study feasibility issues and proof of concept. A ground based experiment of this type is outlined.

Chai, An-Ti; Rashidnia, N.; Arpaci, V. S.

1992-01-01

269

Evaporation Tower With Prill Nozzles  

NASA Technical Reports Server (NTRS)

Tower more efficient than conventional evaporation equipment. Liquids such as milk and fruit juice concentrated by passing them through tiny nozzle to form droplets, then allowing droplets to fall through evacuated tower with cooled walls.

Du Fresne, E. R.

1984-01-01

270

Electrostatic Deflection Binary Alloy Evaporator.  

National Technical Information Service (NTIS)

A new technique for producing thin film binary alloys is discussed which used periodic deflection of an electron beam between two sources in a vacuum evaporator. This technique makes it possible to produce high quality binary alloys of predetermined ratio...

E. A. Stern J. L. Erskine J. M. Tracy

1970-01-01

271

Generator with Direct Evaporative Cooling.  

National Technical Information Service (NTIS)

The design of an electrical machine with high intensity evaporative cooling is described. Experimental data and relationships describing the process of cooling the machine, taking account of the effect of external conditions, are presented. The basic calc...

V. I. Naumenko V. A. Mochalov

1974-01-01

272

Evaporative Losses from Cooling Ponds.  

National Technical Information Service (NTIS)

Cooling ponds have been routinely utilized for the dissipation of industrial waste heat. The present study describes some analyses of this evaporation and means to measure and/or calculate it. Mathematical models using an energy budget approach are shown ...

B. L. Sill

1983-01-01

273

Dual manifold heat pipe evaporator  

DOEpatents

An improved evaporator section is described for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes. 1 figure.

Adkins, D.R.; Rawlinson, K.S.

1994-01-04

274

Dual manifold heat pipe evaporator  

DOEpatents

An improved evaporator section for a dual manifold heat pipe. Both the upper and lower manifolds can have surfaces exposed to the heat source which evaporate the working fluid. The tubes in the tube bank between the manifolds have openings in their lower extensions into the lower manifold to provide for the transport of evaporated working fluid from the lower manifold into the tubes and from there on into the upper manifold and on to the condenser portion of the heat pipe. A wick structure lining the inner walls of the evaporator tubes extends into both the upper and lower manifolds. At least some of the tubes also have overflow tubes contained within them to carry condensed working fluid from the upper manifold to pass to the lower without spilling down the inside walls of the tubes.

Adkins, Douglas R. (Albuquerque, NM) [Albuquerque, NM; Rawlinson, K. Scott (Albuquerque, NM) [Albuquerque, NM

1994-01-01

275

Modeling of droplet evaporation from a nebulizer in an inductively coupled plasma  

NASA Astrophysics Data System (ADS)

The evaporation rate of sample droplets in an inductively coupled plasma is investigated through the development of two models using the direct simulation Monte Carlo technique. A standard continuum evaporation model is contrasted with a kinetic technique designed to obtain correct results over a large range of Knudsen numbers. The droplet evaporation rates predicted by the continuum desolvation model are found to be in agreement with those of previous studies. We present the first predicted spatial distribution of droplet concentrations and evaporation rates in an ICP flow. .

Benson, Craig M.; Gimelshein, Sergey F.; Levin, Deborah A.; Montaser, Akbar

2001-08-01

276

FIrDA-SSL: experiments with securing communication in PANs  

Microsoft Academic Search

In personal area networks (PANs), a personal operating space (POS) surrounds the person up to 10 meters in all directions and it contains several types of wireless devices exchanging data between them (intra-PAN communication), or with devices from another POS or as part of broader networks (inter-PAN communication). Security is seen as a \\

Diana Berbecaru

2005-01-01

277

The role of pore clusters (wet patches) on evaporation dynamics from drying porous surfaces  

NASA Astrophysics Data System (ADS)

Theoretical and experimental evidence suggests that the relationship between evaporative flux and porous surface water content is nonlinear (i.e., the reduction in flux is not proportional to reduction in water content). These nonlinearities are attributed to flux compensation due to interactions between evaporation from discrete pores whose spacing increases with surface drying and air boundary layer. Motivated by recent insights on the interplay between boundary layer thickness, pore size and spacing on surface fluxes, we examine effects of pore clustering on evaporation rates, addressing the question do pore clusters behave like large pores? Evaporation rate from clustered surfaces was determined theoretically using analytical and numerical methods, and results were compared to experiments. We exposed porous surfaces with different pore clusters arranged in different patterns to prescribed evaporative conditions in a wind tunnel with air velocities between 1 and 4 m/s (to vary the thickness of viscous boundary layer). The water saturated porous plates were covered by impervious plates with fixed evaporating area distributed between 1 to 169 clusters. The evaporation rate (relative to free water evaporation) decreased with increasing cluster size ("big pores") and decreasing boundary layer thickness. Experimental findings suggest that clustering reduces evaporation rates relative to distributed pores, however this effect is limited to cluster sizes of about 10 mm (of the order of maximum boundary layer thickness studied). The results were in agreement with model predictions that yield a universal scaling function for estimation of evaporation reduction by pore clustering for different boundary conditions.

Or, Dani; Breitenstein, Daniel; Lehmann, Peter

2013-04-01

278

DWPF Recycle Evaporator Simulant Tests  

SciTech Connect

Testing was performed to determine the feasibility and processing characteristics of an evaporation process to reduce the volume of the recycle stream from the Defense Waste Processing Facility (DWPF). The concentrated recycle would be returned to DWPF while the overhead condensate would be transferred to the Effluent Treatment Plant. Various blends of evaporator feed were tested using simulants developed from characterization of actual recycle streams from DWPF and input from DWPF-Engineering. The simulated feed was evaporated in laboratory scale apparatus to target a 30X volume reduction. Condensate and concentrate samples from each run were analyzed and the process characteristics (foaming, scaling, etc) were visually monitored during each run. The following conclusions were made from the testing: Concentration of the ''typical'' recycle stream in DWPF by 30X was feasible. The addition of DWTT recycle streams to the typical recycle stream raises the solids content of the evaporator feed considerably and lowers the amount of concentration that can be achieved. Foaming was noted during all evaporation tests and must be addressed prior to operation of the full-scale evaporator. Tests were conducted that identified Dow Corning 2210 as an antifoam candidate that warrants further evaluation. The condensate has the potential to exceed the ETP WAC for mercury, silicon, and TOC. Controlling the amount of equipment decontamination recycle in the evaporator blend would help meet the TOC limits. The evaporator condensate will be saturated with mercury and elemental mercury will collect in the evaporator condensate collection vessel. No scaling on heating surfaces was noted during the tests, but splatter onto the walls of the evaporation vessels led to a buildup of solids. These solids were difficult to remove with 2M nitric acid. Precipitation of solids was not noted during the testing. Some of the aluminum present in the recycle streams was converted from gibbsite to aluminum oxide during the evaporation process. The following recommendations were made: Recycle from the DWTT should be metered in slowly to the ''typical'' recycle streams to avoid spikes in solids content to allow consistent processing and avoid process upsets. Additional studies should be conducted to determine acceptable volume ratios for the HEME dissolution and decontamination solutions in the evaporator feed. Dow Corning 2210 antifoam should be evaluated for use to control foaming. Additional tests are required to determine the concentration of antifoam required to prevent foaming during startup, the frequency of antifoam additions required to control foaming during steady state processing, and the ability of the antifoam to control foam over a range of potential feed compositions. This evaluation should also include evaluation of the degradation of the antifoam and impact on the silicon and TOC content of the condensate. The caustic HEME dissolution recycle stream should be neutralized to at least pH of 7 prior to blending with the acidic recycle streams. Dow Corning 2210 should be used during the evaporation testing using the radioactive recycle samples received from DWPF. Evaluation of additional antifoam candidates should be conducted as a backup for Dow Corning 2210. A camera and/or foam detection instrument should be included in the evaporator design to allow monitoring of the foaming behavior during operation. The potential for foam formation and high solids content should be considered during the design of the evaporator vessel.

Stone, M

2005-04-05

279

A model of the biogeographical journey from Proto-pan to Pan paniscus.  

PubMed

Pan paniscus is unique in the group of African apes because of its range south of the Congo River. Examination of the bio-geographical journey of the genus Pan to the species P. paniscus is important when discussing the evolution of African apes. This paper is a review of the paleo-geographic events, the zoogeography, and faunal sorting which influenced P. paniscus divergence from the Proto-pan ancestor within the recent Miocene through Pliocene Epochs, approximately 10-2 MYA. Finally, by elucidating modern day evidence of food plant forms in the southern periphery exploited by P. paniscus in the forest/savanna mosaic habitat, we are able to conclude with those extrinsic events that most influenced the occurrence and distribution of P. paniscus. PMID:12687485

Myers Thompson, Jo A

2003-04-01

280

Pan Eurasian Experiment (PEEX): a new research initiative focused on the Northern Pan-Eurasian Region  

NASA Astrophysics Data System (ADS)

The increasing human activities are changing the environment and the humanity is we are pushing the safe boundaries of the globe. It is of utmost importance to gauge with a comprehensive research program on the current status of the environment, particularly in the most vulnerable locations. Pan-Eurasian Experiment (PEEX) is a new multidisciplinary research approach aiming at resolving the major uncertainties in the Earth system science and global sustainability questions in the Arctic and boreal Pan-Eurasian regions. The PEEX program aims (i) to understand the Earth system and the influence of environmental and societal changes in pristine and industrialized Pan-Eurasian environments, (ii) to establish and sustain long-term, continuous and comprehensive ground-based airborne and seaborne research infrastructures, and to utilize satellite data and multi-scale model frameworks, (iii) to contribute to regional climate scenarios in the northern Pan-Eurasia and determine the relevant factors and interactions influencing human and societal wellbeing (iv) to promote the dissemination of PEEX scientific results and strategies in scientific and stake-holder communities and policy making, (v) to educate the next generation of multidisciplinary global change experts and scientists, and (vi) to increase the public awareness of climate change impacts in the Pan-Eurasian region. The development of PEEX research infrastructure will be one of the first activities of PEEX. PEEX will find synergies with the major European land-atmosphere observation infrastructures such as ICOS a research infrastructure to decipher the greenhouse gas balance of Europe and adjacent regions, ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network-project), and ANAEE (The experimentation in terrestrial ecosystem research) networks and with the flag ship stations like the SMEARs (Station for Measuring Ecosystem-Atmosphere Relations) when design, re-organizing and networking existing stations networks in the Northern Pan-Eurasian region.

Petj, Tuukka; Lappalainen, Hanna; Zaytseva, Nina; Shvidenko, Anatoli; Kujansuu, Joni; Kerminen, Veli-Matti; Viisanen, Yrj; Kotlyakov, Vladimir; Kasimov, Nikolai; Bondur, Valery; Matvienko, Gennadi; Zilitinkevich, Sergej; Kulmala, Markku

2014-05-01

281

EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS  

SciTech Connect

We present the novel concept of evaporation of planetesimals as a result of bow shocks associated with planetesimals orbiting with supersonic velocities relative to the gas in a protoplanetary disk. We evaluate the evaporation rates of the planetesimals based on a simple model describing planetesimal heating and evaporation by the bow shock. We find that icy planetesimals with radius {approx}>100 km evaporate efficiently even outside the snow line in the stage of planetary oligarchic growth, where strong bow shocks are produced by gravitational perturbations from protoplanets. The obtained results suggest that the formation of gas giant planets is suppressed owing to insufficient accretion of icy planetesimals onto the protoplanet within the {approx}<5 AU disk region.

Tanaka, Kyoko K.; Yamamoto, Tetsuo; Tanaka, Hidekazu [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan)] [Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819 (Japan); Miura, Hitoshi [Department of Earth Sciences, Tohoku University, Sendai 980-8578 (Japan)] [Department of Earth Sciences, Tohoku University, Sendai 980-8578 (Japan); Nagasawa, Makiko; Nakamoto, Taishi [Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)] [Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

2013-02-20

282

Evaporative Emission Model (EVAP 3. 0) (for microcomputers). Software  

SciTech Connect

The potential role of automotive evaporative emissions in the formation of photochemical smog has underscored the need for an accurate evaluation of real-world motor vehicle evaporative emission rates. Two general categories of information are needed to predict evaporative emissions for vehicles in actual use. The first category defines the environment that a vehicle experiences in the real world. This includes conditions such as driving pattern, ambient temperature, refueling behavior, and gasoline Reid vapor pressure (RVP). The second category describes how the vehicle responds to these conditions. This includes weathering of the fuel in the fuel tank and how evaporative emissions vary as a function of RVP, ambient temperature, and fuel tank level.

Not Available

1993-02-01

283

Mathematical simulation for non-equilibrium droplet evaporation  

NASA Astrophysics Data System (ADS)

Investigations of acute problems of phase transitions in continua mechanics need adequate modeling of evaporation, which is extremely important for the curved surfaces in the presence of strong heat and mass diffusion fluxes. Working cycle of heat pipes is governed by the active fluid evaporation rate. Combustion of most widely spread hydrocarbon fuels takes place in a gas-phase regime. Thus, evaporation of fuel from the surface of droplets turns to be one of the limiting factors of the process as well. In the present paper processes of non-equilibrium evaporation of small droplets in a quiescent air and in streaming gas flows were investigated theoretically. The rate of droplet evaporation is characterized by a dimensionless Peclet number ( Pe). A new dimensionless parameter I characterizing the deviation of phase transition from the equilibrium was introduced, which made it possible to investigate its influence on variations of the Peclet number and to determine the range of applicability for the quasi-equilibrium model. As it follows from the present investigations accounting for non-equilibrium effects in evaporation for many types of widely used liquids is crucial for droplets diameters less than 100?m, while the surface tension effects essentially manifest only for droplets below 0.1?m. The effects of velocity non-equilibrium and droplet atomization were taken into account.

Dushin, V. R.; Kulchitskiy, A. V.; Nerchenko, V. A.; Nikitin, V. F.; Osadchaya, E. S.; Phylippov, Yu. G.; Smirnov, N. N.

2008-12-01

284

The interaction of evaporative and convective instabilities  

NASA Astrophysics Data System (ADS)

Evaporative convection arises in a variety of natural and industrial processes, such as drying of lakebeds, heat pipe technology and dry-eye syndrome. The phenomenon of evaporative convection leads to an interfacial instability where an erstwhile flat surface becomes undulated as a control variable, such as temperature drop, exceeds a critical value. This instability has been investigated by others assuming that the vapor phase is infinitely deep and passive, i.e. vapor fluid dynamics has been ignored. However, when we look at some engineering processes, such as distillation columns, heat pipes and drying technologies where phase change takes place we might imagine that the assumption of an infinitely deep vapor layer or at least that of a passive vapor is inappropriate. Previous work on convection in bilayer systems with no phase-change suggests that active vapor layers play a major role in determining the stability of an interface. Hence, for the case of convection with phase-change, we will address this issue and try to answer the question whether the infinitely deep and passive vapor layer is a valid assumption. We have also 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 and the finiteness of the domains of each phase, i.e. 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 physically different problems.

Ozen, O.

285

Evaporation of volatile organic compounds from human skin in vitro.  

PubMed

The specific evaporation rates of 21 volatile organic compounds (VOCs) from either human skin or a glass substrate mounted in modified Franz diffusion cells were determined gravimetrically. The diffusion cells were positioned either on a laboratory bench top or in a controlled position in a fume hood, simulating indoor and outdoor environments, respectively. A data set of 54 observations (34 skin and 20 glass) was assembled and subjected to a correlation analysis employing 5 evaporative mass transfer relationships drawn from the literature. Models developed by Nielsen et al. (Prediction of isothermal evaporation rates of pure volatile organic compounds in occupational environments: a theoretical approach based on laminar boundary layer theory. Ann Occup Hyg 1995;39:497-511.) and the U.S. Environmental Protection Agency (Peress, Estimate evaporative losses from spills. Chem Eng Prog 2003; April: 32-34.) were found to be the most effective at correlating observed and calculated evaporation rates under the various conditions. The U.S. EPA model was selected for further use based on its simplicity. This is a turbulent flow model based only on vapor pressure and molecular weight of the VOC and the effective air flow rate u. Optimum values of u for the two laboratory environments studied were 0.23 m s(-1) (bench top) and 0.92 m s(-1) (fume hood). PMID:23609116

Gajjar, Rachna M; Miller, Matthew A; Kasting, Gerald B

2013-08-01

286

Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop  

NASA Technical Reports Server (NTRS)

Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation -retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 min and less till drying up, though the evaporation rate is gradually slowing down.

Zhang, Nengli; Chao, David F.; Singh, Bhim S. (Technical Monitor)

2000-01-01

287

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

2012-01-15

288

Heat Transfer Performance for Evaporator of Absorption Refrigerating Machine  

NASA Astrophysics Data System (ADS)

An experiment was conducted to check the heat transfer performance of evaporators with grooved tubes for absorption refrigerating machines. Heat transfer rate of evaporators were 35kW and 70kW. The range of the flow rate of the sprayed refrigerant per unit length ? was 1 to 50kg/hm, and the outside diameters of the tubes, D0 were 16 and 19.6 mm. About 80 to 100 % increase of heat transfer rate over a plane surfaced tube is obtained by using grooved tube. The heat transfer coefficients for evaporation are correlated by the equation ?E0=(?/D0)1/2. The substantial surface area, which is about three times larger than that of plane surfaced tube, is used in the above correlation.

Kunugi, Yoshifumi; Usui, Sanpei; Ouchi, Tomihisa; Fukuda, Tamio

289

Some limnological observations of a temporary West Coast pan in Southern Africa: Rocher Pan  

Microsoft Academic Search

The mineral contents and some of the primary consumers of a temporary pan along the west coast of southern Africa are reported\\u000a on. Tendential evidence suggests a change in composition and abundance of the entomostraca which could probably be related\\u000a to floristic changes caused by the accumulation of salts.

A. Coetzer

1981-01-01

290

Phase 2 report on the evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes  

Microsoft Academic Search

The performance of PAN-based composite absorbers was evaluated in dynamic experiments at flow rates ranging from 25--100 bed volumes (BV) per hour. Composite absorbers with active components of ammonium molybdophosphate (AMP) PAN and K-Co ferrocyanide (KCoFC) PAN were used for separating Cs from a 1 M HNO + 1 M NaNO + 2 10⁻⁵ M CsCl acidic simulant solution.

F. Sebesta; J. John; A. Motl

1996-01-01

291

In-air PIXE for analyzing heavy metals in water boiled in pans  

Microsoft Academic Search

The release rates of heavy metals from pans were measured for boiling water as well as for an acidic solution prior to an investigation on the release or sorption of trace elements due to cooking of food by boiling. The boiled samples were condensed and analyzed by means of in-air PIXE. The release of heavy metals was measured for five

M. Tomita; Y. Haruyama; M. Saito

1993-01-01

292

Improving the conceptualization of the evaporation flux in conceptual rainfall-runoff models by using remotely sensed catchment scale evaporation estimates.  

NASA Astrophysics Data System (ADS)

If we look at how evaporation is modelled in commonly used lumped conceptual rainfall-runoff models, the static nature of the conceptualization is striking. In this conceptualization the evaporation flux usually is linearly related to the relative soil moisture content until a certain threshold is reached, after which evaporation takes place at the potential rate. The potential evaporation is a function of meteorological parameters, sometimes it includes a surface resistance term or a scaling factor to account for different land use types in the catchment. Vegetation specific variables and the dynamics associated with the seasons (e.g. phenology, effects of soil temperature) are generally not explicitly taken into account. This means that the dynamic character of evaporation in these lumped rainfall-runoff models is only expressed by the dynamics in water availability - i.e. a function of precipitation (model input) and the partitioning of water - and a form of available energy for vaporization. Moreover, the modeled evaporation flux is the aggregated flux over the entire catchment. How can spatial variability in the temporal dynamics be expressed in these models? In other words, to what extent does the modeled evaporation flux represent the 'real' evaporation integrated over the entire catchment? Since temporally continuous evaporation observations are not available at the scale of the catchment this cannot be tested straightforwardly. What is available is a range of remote sensing techniques for upscaling point measurements of evaporation to the catchment scale or to estimate evaporation from thermal images. In this research catchment scale evaporation estimates from the SEBS algorithm combined with optical remote sensing data are explored. This provides snapshots of the spatial variability of evaporation throughout the year, which can be used to determine homogeneous functional areas within the catchment with comparable temporal dynamics in evaporation. With that information the switch to a semi-distributed model can be made, providing the possibility to capture more of the spatial and temporal character of evaporation by adjusting the conceptualization and/or parameterization of the evaporation flux per 'functional area'. We analyze the value of the ancillary remote sensing evaporation data and whether we can use this data to actually improve the conceptualization of the evaporation flux and therewith model performance.

Aalbers, Emma; Coenders-Gerrits, Miriam; Savenije, Hubert

2014-05-01

293

Electrical activation of PAN-Pt artificial muscles  

NASA Astrophysics Data System (ADS)

Activated polyacrylonitrile (PAN) fibers are known to elongate and contract when immersed in caustic and acidic solutions, respectively. The change in length for these pH activated fibers is greater than 100% and are comparable in strength to human muscle, yet need of strong acids and bases for actuation has limited the use of PAN fibers as linear actuators or artificial muscles. Increasing the conductivity of PAN by depositing platinum within the fibers has allowed for electrical activation of PAN artificial muscles when it is placed in an electrochemical cell. The electrolysis of water in such a cell produces hydrogen ions at a PAN anode, thus locally decreasing the pH and causing the PAN muscle to contract. Reversing the electric field allows the PAN muscle to elongate. A 40% change in PAN muscle length in less than 10 minutes is observed when it is placed as an electrode in a 10 mM NaCl electrolyte solution and connected to a 20 volt power supply. These initial results indicate potential in developing electrically activated PAN muscles and linear actuators, which would be much more applicable than chemically activated PAN.

Schreyer, H. Brett; Shahinpoor, Mohsen; Kim, Kwang J.

1999-05-01

294

First Results from Pan-STARRS 1  

NASA Astrophysics Data System (ADS)

We will present the first solar system results from the prototype telescope (PS1) for the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The PS1 1.8m telescope is located on Haleakala, Maui, Hawaii. The telescope and camera system provide a 3 deg wide circular field of view that has been instrumented with a 1.4 billion pixel camera at about 0.3"/pixel. Despite the large number of pixels we read the camera out in ? seconds with a read noise of about 6 electrons. The large field of view and rapid readout at low noise is achieved at reasonable cost using orthogonal transfer array (OTA) CCDs. When fully operational we expect PS1 to image about 3000 sq. deg. twice/night on three nights per lunation in a large opposition region area and two smaller 'sweet-spot' areas at small solar elongation.

Jedicke, Robert; Pan-STARRS PS1 Science Consortium

2009-09-01

295

The Pan-STARRS Moving Object Pipeline  

NASA Astrophysics Data System (ADS)

The Moving Object Processing System (MOPS) team of the University of Hawaii's Pan-STARRS telescope is developing software to automatically discover and identify >90% of near-Earth objects (NEOs) larger than 300 m, and >80% of other classes of asteroids and comets. MOPS relies on new, efficient, multiple-hypothesis KD-tree and variable-tree search algorithms to search the 10^{12} detection pairs that are expected per night. Candidate intra- and inter-night associations of detections are evaluated for consistency with a real solar system object, and orbits are computed. We describe the basic operation of the MOPS pipeline, identify pipeline processing steps that are candidates for multiple-hypothesis spatial searches, describe our implementation of those algorithms, and provide preliminary results for MOPS.

Denneau, L., Jr.; Kubica, J.; Jedicke, R.

2007-10-01

296

Evaporation control research, 1959-60  

USGS Publications Warehouse

Two hundred and forty-five dispersions of long-chain alkanols were formulated by using various emulsifiers and alkanols. The dispensing and spreading ability of each of these formulations was tested. The most promising emulsifier that could be used with any of the alkanols was glyceryl monostearate (self-emulsifying). However, the concentration of the alkanol in the dispersion form varied somewhat: with the length of the carbon chain. A maximum concentration of 16 percent was obtained using the longer chain alkanols in the dispersion form without losing any of the properties of a fluid. Nine field tests were undertaken on small stock tanks. The retardant materials used in these tests were dodecanol, hexadecanol, and octadecanol. These materials were applied in either liquid or dispersion form. Four types of dispensing equipment were tested. The first type used a pressure system which sprayed a liquid onto the surface of the water. An anemometer and wind-controlled vane, operated by an electrical system, determined the length End frequency of application. The second type was similar to the first except that gravity was utilized to force the liquid onto the surface. The third type. used a drip system with rates of about 10 drops per minute. The fourth type used a gravity feed and a wind-controlled valve which allowed the dispersion material to flow onto the surface of the water when the wind was in the proper direction. In the field tests, the best reduction in evaporation was obtained using octadecanol in dispersion form and dispensed with the wind-controlled valve and gravity feed system. The maximum reduction in evaporation for a 2-week period was 27 percent. However, the economics of suppressing evaporation from stock tanks is questionable because of the short travel time across the tank by the film. There are still many problems unsolved. Some of these can be resolved in the laboratory whereas others can be resolved only in the field. Some of the more serious problems are the effect of impurities in the alkanols; the rate of cooling of the alkanol from a liquid to a solid state ; the effect of the film on the exchange of water molecules between the air and water; whether the film remains effective in suppressing evaporation for any rate of movement downwind; and the possible use of dodecanol and eicosanol as suppressants.

Geological Survey (U.S.)

1963-01-01

297

On-board Processing to Advance the PanFTS Imaging System for GEO-CAPE  

NASA Astrophysics Data System (ADS)

The Panchromatic Fourier Transform Spectrometer (PanFTS) is an imaging instrument designed to record atmospheric spectra of the Earth from the vantage point of a geosynchronous orbit. Each observation covers a scene of 128x128 pixels. In order to retrieve multiple chemical families and perform passive vertical profiling, the recorded spectra will cover a wide wavelength range, from the thermal infrared to the near ultraviolet. The small size of the nadir ground-sampling distance and the desire to re-visit each scene hourly result in a PanFTS design that challenges the downlink capabilities of current radio communication. The PanFTS on-board processing will reduce downlink rates by converting time-domain interferograms to band-limited spectra, hence achieving a factor 20 in data reduction. In this paper, we report on the first year progress of this NASA AIST-11 task and on the adaptation of existing Virtex-5 FPGA designs to support the PanFTS Focal Plane Array control and data interfaces. We have produced a software demonstration of the current PanFTS data reduction algorithms. The real-time processing of the interferometer metrology laser signal is the first step required for the conversion of time-domain interferograms to path difference. This laser processing is now performed entirely as digital signal processing inside the Virtex-5 FPGA and also allows for tip/tilt correction of the interferometer mirrors, a task that was previously performed only with complicated and inflexible analog electronics.

Sander, S. P.; Pingree, P.; Bekker, D. L.; Blavier, J. L.; Bryk, M.; Franklin, B.; Hayden, J.; Ryan, M.; Werne, T. A.

2013-12-01

298

Rain scavenging of soluble gases by non-evaporating and evaporating droplets from inhomogeneous atmosphere  

NASA Astrophysics Data System (ADS)

We suggest a one-dimensional model of precipitation scavenging of soluble gaseous pollutants by non-evaporating and evaporating droplets that is valid for arbitrary initial vertical distribution of soluble trace gases in the atmosphere. It is shown that for low gradients of soluble trace gases in the atmosphere, scavenging of gaseous pollutants is governed by a linear wave equation that describes propagation of a wave in one direction. The derived equation is solved by the method of characteristics. Scavenging coefficient and the rates of precipitation scavenging are calculated for wet removal of sulfur dioxide (SO2) and ammonia (NH3) using measured initial distributions of trace gases. It is shown that scavenging coefficient for arbitrary initial vertical distribution of soluble trace gases in the atmosphere is non-stationary and height-dependent. In case of exponential initial distribution of soluble trace gases in the atmosphere, scavenging coefficient for non-evaporating droplets in the region between the ground and the position of a scavenging front is a product of rainfall rate, solubility parameter, and the growth constant in the formula for the initial profile of a soluble trace gas in the atmosphere. This expression yields the same estimate of scavenging coefficient for sulfur dioxide scavenging by rain as field estimates presented in McMahon and Denison (1979). It is demonstrated that the smaller the slope of the concentration profile the higher the value of a scavenging coefficient.

Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

2013-11-01

299

Optimization of thermoelectric thin-films deposited by co-evaporation on plastic substrates  

Microsoft Academic Search

The optimization of the thermal co-evaporation process for n- type Bismuth Telluride and p-type Antimony Telluride onto plastic substrates (Kapton polyimide) for thermoelectric applications is reported. Films were co-evaporated from Bismuth and Tellurium or Antimony and Tellurium to obtain Bi2Te3 or Sb2Te3, respectively. The evaporation rate of each material was monitorized using a crystal oscillator sensor and the power applied

L. M. Goncalves; C. Couto; J. H. Correia; P. Alpuim; Gao Min; D. M. Rowe

300

An investigation on the estimation of evaporation by combining artificial neural network and dynamic factor analysis  

NASA Astrophysics Data System (ADS)

Evaporation is a substantial factor in hydrological circle, moreover a significant reference to the management of both water resources and agricultural irrigation. In general, evaporation can be directly measured by evaporation pan. As for its estimation, the accuracy of traditional empirical equation is not very precise. Therefore, in this study the Dynamic Factor Analysis (DFA) is first applied to investigating the interaction and the tendency of each gauging station. Additionally, the analysis can effectively establish the common trend at each gauging station by evaluating the corresponding AIC (Akaike Information Criterion) values. Furthermore, the meteorological factors such as relative humidity and temperature are also conducted to identify the explanatory variables which have higher relation to evaporation. These variables are further used as inputs to the Back-Propagation Neural Network (BPNN) and are expected to provide meaningful information for successfully estimating evaporation. The applicability and reliability of the BPNN was demonstrated by comparing its performance with that of empirical formula. Keywords: Evaporation, Dynamic Factor Analysis, Artificial Neural Network.

Sun, W.; Chiang, Y.; Chang, F.

2010-12-01

301

Trends in evaporation and surface cooling in the Mississippi River basin  

USGS Publications Warehouse

A synthesis of available data for the Mississippi River basin (area 3 ?? 106 km2) reveals an upward trend in evaporation during recent decades, driven primarily by increases in precipitation and secondarily by human water use. A cloud-related decrease in surface net radiation appears to have accompanied the precipitation trend. Resultant evaporative and radiative cooling of the land and lower atmosphere quantitatively explains downward trends in observed pan evaporation. These cooling tendencies also reconcile the observed regional atmospheric cooling with the anticipated regional "greenhouse warming." If recent high levels of precipitation (which correlate with the North Atlantic Oscillation) are mainly caused by an internal climatic fluctuation, an eventual return to normal precipitation could reveal heretofore-unrealized warming in the basin. If, instead, they are caused by some unidentified forcing that will continue to grow in the future, then continued intensification of water cycling and suppression of warming in the basin could result.

Milly, P. C. D.; Dunne, K. A.

2001-01-01

302

Correlations for Saturation Efficiency of Evaporative Cooling Pads  

NASA Astrophysics Data System (ADS)

This paper presents some experimental investigations to obtain correlations for saturation efficiency of evaporative cooling pads. Two commonly used materials namely aspen and khus fibers along with new materials namely coconut fibers and palash fibers were tested in a laboratory using suitably fabricated test setup. Simple mathematical correlations have been developed for calculating saturation efficiency of evaporating cooling pads which can be used to predict their performance at any desired mass flow rate. Performances of four different pad materials were also compared using developed correlations. An attempt was made to test two new materials (i.e. fibers of palash wood and coconut) to check their suitability as wetted media for evaporative cooling pads. It was found that Palash wood fibers offered highest saturation efficiency compared to that of other existing materials such as aspen and khus fibers at different mass flow rate of air.

Jain, J. K.; Hindoliya, D. A.

2014-01-01

303

Floating-roof tank evaporation  

SciTech Connect

The book describes an improved method for estimating the total evaporative losses of the equivalent atmospheric hydrocarbon emissions from external floating-roof tanks that contain multicomponent hydrocarbon mixtures (such as gasolines and crude oils) or single-component stocks (such as petro-chemicals).

Not Available

1989-01-01

304

Membrane evaporator/sublimator investigation  

NASA Technical Reports Server (NTRS)

Data are presented on a new evaporator/sublimator concept using a hollow fiber membrane unit with a high permeability to liquid water. The aim of the program was to obtain a more reliable, lightweight and simpler Extra Vehicular Life Support System (EVLSS) cooling concept than is currently being used.

Elam, J.; Ruder, J.; Strumpf, H.

1974-01-01

305

Rapid Evaporation of Binary Mixture Injections  

NASA Astrophysics Data System (ADS)

When a fuel under pressure is heated above its normal boiling point and expanded through a nozzle into atmospheric conditions, rapid evaporation can occur. The resulting sprays typically exhibit increased atomization and shorter liquid penetration lengths. When heavy fuels with high specific heats are used, complete evaporation is theoretically possible. This is a continuation of work done by Sloss and McCahan (APS/DFD meeting 1996), in which dodecane, fuel oil, kerosene, and diesel oil were studied, and McCahan and Kessler (APS/DFD meeting 1997), in which preliminary results were presented on decane and tetradecane. At a pressure of 10 bar, the working fluid (decane/tetradecane mixture) is preheated to temperatures ranging from room temperature to the decane saturation temperature and then expanded through a simple converging nozzle into a chamber at 1 bar. From the photographic and mass flow rate data, the effect of degree of superheat on the spray cone angle and mass flow rate is observed. Results show that the addition of a heavier hydrocarbon has the expected damping effects on the spray characteristics.

McCahan, S.; Kessler, C.

1998-11-01

306

Transpiration and evaporation from heather Moorland  

NASA Astrophysics Data System (ADS)

The energy balance of an upland heath dominated by heather ( Calluna vulgaris) was measured in dry and wet weather. Median values of both transpiration and evaporation rates were ca. 2 mm hr-1. The median Bowen ratio for the dry canopy was 2.0 and for the wet canopy 0.6. On dry days the median value of the saturation deficit was only 3.8 mb and that of the climatological resistance was 30 s m-1. The bulk stomatal resistance increased from ca. 50 s m -2 in the morning to over 290 s m-1 in the afternoon with an overall median value of 110 s m-1. Transpiration from the dry canopy was controlled by a combination of small saturation deficits and large stomatal resistances. The median value of the boundary-layer resistance of the canopy was 22 s m-1 and was low partly because of a large low-level drag coefficient. Saturation deficits on wet days were close to zero and evaporation of intercepted water proceeded at close to the equilibrium rate, being largely limited by the low fluxes of available energy. The water loss from heather was compared with simulated losses from coniferous forest, herbaceous crops and grassland in the same conditions to evaluate the effects of vegetation on water loss from catchments.

Miranda, A. C.; Jarvis, P. G.; Grace, J.

1984-03-01

307

The ATLAS PanDA Monitoring System and its Evolution  

Microsoft Academic Search

The PanDA (Production and Distributed Analysis) Workload Management System is used for ATLAS distributed production and analysis worldwide. The needs of ATLAS global computing imposed challenging requirements on the design of PanDA in areas such as scalability, robustness, automation, diagnostics, and usability for both production shifters and analysis users. Through a system-wide job database, the PanDA monitor provides a comprehensive

A Klimentov; P Nevski; M Potekhin; T Wenaus

2011-01-01

308

Inter-PAN Mobility Support for 6LoWPAN  

Microsoft Academic Search

This paper proposes Inter PAN mobility support for 6LoWPANs moving within an IP domain. In order to reduce the processing and signaling load on the mobile node (MN) caused by the movement, the mobility related processing of 6LoWPAN nodes is delegated to the existing PAN entities with less power constraints. Also this mobility support mechanism aims to reduce Inter-PAN Handover

Gargi Bag; Hamid Mukhtar; S. M. S. Shams; Ki Hyung Kim; Seung-wha Yoo

2008-01-01

309

Facile Approach to Synthesize g-PAN/g-C3N4 Composites with Enhanced Photocatalytic H2 Evolution Activity.  

PubMed

Novel composites consisting of graphitized polyacrylonitrile (g-PAN) nanosheets grown on layered g-C3N4 sheets were synthesized through a facile one-step thermal condensation of PAN and melamine for the first time. Photoluminescence spectroscopy and the photoelectrochemical measurements reveal that g-PAN nanosheets act as effective electron transfer channels to facilitate charge carrier separation in g-PAN/g-C3N4 composites. The g-PAN/g-C3N4 composites exhibit significantly enhanced visible-light photocatalytic performance for H2 evolution over pristine g-C3N4. The 5.0 wt % g-PAN/g-C3N4 composite has optimal H2 evolution rate of 37 ?mol h(-1), exceeding 3.8 times over pristine g-C3N4. We have proposed a possible mechanism for charge separation and transfer in the g-PAN/g-C3N4 composites to explain the enhanced photocatalytic performance. PMID:24797448

He, Fang; Chen, Gang; Yu, Yaoguang; Hao, Sue; Zhou, Yansong; Zheng, Yi

2014-05-28

310

Heterochrony and geometric morphometrics: a comparison of cranial growth in Pan paniscus versus Pan troglodytes.  

PubMed

Heterochrony, the classic framework in which to study ontogeny and phylogeny, in essence relies on a univariate concept of shape. Though principal component (PC) plots of multivariate shape data seem to resemble classical bivariate allometric plots, the language of heterochrony cannot be translated directly into general multivariate methodology. We simulate idealized multivariate ontogenetic trajectories and explore their appearance in PC plots of shape space and size-shape space. Only if the trajectories of two related species lie along exactly the same path in shape space can the classic terminology of heterochrony apply and pure dissociation of size change against shape change be detected. Regional heterochrony--the variation of apparent heterochrony by region--implies a dissociation of local growth fields and cannot be identified in an overall PC analysis. We exemplify a geometric morphometric approach to these issues using adult and subadult crania of 48 Pan paniscus and 47 Pan troglodytes specimens. On each specimen, we digitized 47 landmarks and 144 semilandmarks on facial curves and the external neurocranial surface. We reject the hypothesis of global heterochrony in the cranium of Pan as well as regional heterochrony for the lower face, the upper face, and the neurocranium. PMID:15876197

Mitteroecker, Philipp; Gunz, Philipp; Bookstein, Fred L

2005-01-01

311

The influence of chelating reagents on plumbane generation: Determination of lead in the presence of PAN-S.  

PubMed

A series of 22 chelating reagents were tested for plumbane generation. Besides nitroso R salt, the reagents Bromo Pyrogallol Red, Pyrocatechol Violet, Alizarine Red-S, 5-Br-PADAP and PAN-S could significantly enhance the lead signal. The PAN-S system has been optimized. The characteristic concentration (5 ml sample) is 1.3 ng/ml, and the RSD at the 50 ng/ml level is 3.9%. Lead spiked into tap water and natural water was determined by HG-AAS in the presence of PAN-S. Recoveries of spiked lead were between 90 and 105 %. Study of the mechanism suggests that the lead hydride might be directly generated from the chelated Pb(II) instead of the metastable Pb(IV). PMID:18965761

Chen, H; Tang, F; Gu, C; Brindle, I D

1993-08-01

312

Phase 2 report on the evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes.  

National Technical Information Service (NTIS)

The performance of PAN-based composite absorbers was evaluated in dynamic experiments at flow rates ranging from 25--100 bed volumes (BV) per hour. Composite absorbers with active components of ammonium molybdophosphate (AMP) PAN and K-Co ferrocyanide (KC...

F. Sebesta J. John A. Motl

1996-01-01

313

Pan-African granulite formation in the Kabye Massif of northern Togo (West Africa): Pb-Pb zircon ages  

NASA Astrophysics Data System (ADS)

Metamorphic zircons from seven granulite facies orthogneisses of tonalitic composition (enderbites), collected from four different nappes of the Kabye Massif in the Dahomeyide belt of northern Togo, were dated by the Pb-Pb evaporation method. They yielded consistent Neoproterozoic ages with a mean of 612.5 +/-0.8Ma, interpreted to reflect the peak of regional granulite facies metamorphism following Pan-African continental collision between the West African and Benin-Nigerian plates. These results support previous ages obtained by various chronometers on high-grade rocks from the same suture zone and from surrounding units in Togo, Benin and Ghana. They are also similar to zircon ages from granulites in the Mozambique belt of souteastern Africa. These Pan-African metamorphic ages reflect continental amalgamation resulting in the formation of the Gondwana supercontinent towards the end of the Neoproterozoic.

Affaton, P.; Krner, A.; Seddoh, K. F.

314

Evaporative cooling of speleothem drip water  

PubMed Central

This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as ?18O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change.

Cuthbert, M. O.; Rau, G. C.; Andersen, M. S.; Roshan, H.; Rutlidge, H.; Marjo, C. E.; Markowska, M.; Jex, C. N.; Graham, P. W.; Mariethoz, G.; Acworth, R. I.; Baker, A.

2014-01-01

315

Evaporative cooling of speleothem drip water.  

PubMed

This study describes the first use of concurrent high-precision temperature and drip rate monitoring to explore what controls the temperature of speleothem forming drip water. Two contrasting sites, one with fast transient and one with slow constant dripping, in a temperate semi-arid location (Wellington, NSW, Australia), exhibit drip water temperatures which deviate significantly from the cave air temperature. We confirm the hypothesis that evaporative cooling is the dominant, but so far unattributed, control causing significant disequilibrium between drip water and host rock/air temperatures. The amount of cooling is dependent on the drip rate, relative humidity and ventilation. Our results have implications for the interpretation of temperature-sensitive, speleothem climate proxies such as ?(18)O, cave microecology and the use of heat as a tracer in karst. Understanding the processes controlling the temperature of speleothem-forming cave drip waters is vital for assessing the reliability of such deposits as archives of climate change. PMID:24895139

Cuthbert, M O; Rau, G C; Andersen, M S; Roshan, H; Rutlidge, H; Marjo, C E; Markowska, M; Jex, C N; Graham, P W; Mariethoz, G; Acworth, R I; Baker, A

2014-01-01

316

Effects of Lily Pads on Evaporation  

NASA Astrophysics Data System (ADS)

Measurements of evaporation from open water and water partially covered by lily pads have indicated that for the portion of the surface area covered by lily pads, evaporation is reduced to about 84% of that occurring from open water.

Cooley, Keith R.; Idso, Sherwood B.

1980-06-01

317

Isotopic Compositions of Evaporative Fluxes  

NASA Astrophysics Data System (ADS)

The isotopic fluxes of evaporation from a water surface are typically computed using a one-dimensional model, originally conceptualized by Craig and Gordon (1965) and further developed and adapted to different natural settings (such as transpiration, open surface evaporation, etc.) by various investigators. These models have two distinguishing characteristics. First, there exists a laminar layer where molecular diffusion away from the water-air interface causes kinetic isotopic fractionation. The magnitude of this fractionation is controlled by the diffusion/transport coefficient of each vapor isotopologue in air and their concentration gradients, the latter being controlled by relative humidity, isotopic ratios of ambient air, and turbulent conditions (such as wind and surface roughness). Second, the horizontal variations are ignored. In particular, the effect of horizontal advection on isotopic variations in the ambient air is not considered. The research reported here addresses the effects of relinquishing the simplifying assumptions in both of these areas. We developed a model, in which the simplification of a purely laminar layer is dropped. Instead, we express the vertical transport coefficient as the sum of the molecular diffusivity, that differs for each water isotopologue, and the turbulent diffusivity that increases linearly with height but does not vary among water isotopologues. With this model, the kinetic isotopic effect reduces with height in the vicinity of the water surface, and the net isotopic fractionation through the boundary layer can be integrated. The advantage of this conceptualization is that the magnitude of kinetic isotopic fractionation can be assessed directly with changing environmental conditions, such as humidity and wind speed, rather than approximated by discontinuous empirical functions of the environmental conditions, as in the conventional models mentioned above. To address the effect of lateral heterogeneity, we expanded the model to 2-D and incorporated horizontal advection. The effect of advection was tested and modeled with data collected at several lakes located near Kangerlussuaq, Greenland. As predicted by the model, we observed both vertical as well as horizontal gradients as relatively dry and isotopically depleted air advects over a lake surface. Compared to the standard 1-D model, the 2-D model produced more realistic but significantly depleted isotopic fluxes of evaporation within 500 meters from the upwind shore. This is because of the time and/or distance needed for the dry air to equilibrate with vapor evaporated from the lake. The results suggest that the 1-D model is not adequate for simulating evaporation when the fetch over the water surface is small. This result is important for lake hydrological studies and for understanding and modeling isotopic fluxes of evaporation from sea ice leads that are of limited fetch.

Feng, X.; Lauder, A. M.; Kopec, B. G.; Dade, W. B.; Virginia, R. A.; Posmentier, E. S.

2013-12-01

318

How to Pan-Sharpen Images Using the Gram-Schmidt Pan-Sharpen Method - a Recipe  

NASA Astrophysics Data System (ADS)

Since its publication in 1998 (Laben and Brower, 2000), the Gram-Schmidt pan-sharpen method has become one of the most popular algorithms to pan-sharpen multispectral (MS) imagery. It outperforms most other pan-sharpen methods in both maximizing image sharpness and minimizing color distortion. It is, on the other hand, also more complex and computationally expensive than most other methods, as it requires forward and backward transforming the entire image. Another complication is the lack of a clear recipe of how to compute the sensor dependent MS to Pan weights that are needed to compute the simulated low resolution pan band. Estimating them from the sensor's spectral sensitivity curves (in different ways), or using linear regression or least square methods are typical candidates which can include other degrees of freedom such as adding a constant offset or not. As a result, most companies and data providers do it somewhat differently. Here we present a solution to both problems. The transform coefficients can be computed directly and in advance from the MS covariance matrix and the MS to Pan weights. Once the MS covariance matrix is computed and stored with the image statistics, any small section of the image can be pan-sharpened on the fly, without having to compute anything else over the entire image. Similarly, optimal MS to Pan weights can be computed directly from the full MS-Pan covariance matrix, guaranteeing optimal image quality and consistency.

Maurer, T.

2013-05-01

319

A pan-African Flood Forecasting System  

NASA Astrophysics Data System (ADS)

The African Flood Forecasting System (AFFS) is a probabilistic flood forecast system for medium- to large-scale African river basins, with lead times of up to 15 days. The key components are the hydrological model LISFLOOD, the African GIS database, the meteorological ensemble predictions of the ECMWF and critical hydrological thresholds. In this paper the predictive capability is investigated in a hindcast mode, by reproducing hydrological predictions for the year 2003 where important floods were observed. Results were verified with ground measurements of 36 subcatchments as well as with reports of various flood archives. Results showed that AFFS detected around 70% of the reported flood events correctly. In particular, the system showed good performance in predicting riverine flood events of long duration (>1 week) and large affected areas (>10 000 km2) well in advance, whereas AFFS showed limitations for small-scale and short duration flood events. The case study for "Save flooding" illustrated the good performance of AFFS in forecasting timing and severity of the floods, gave an example of the clear and concise output products, and showed that the system is capable of producing flood warnings even in ungauged river basins. Hence, from a technical perspective, AFFS shows a large potential as an operational pan-African flood forecasting system, although issues related to the practical implication will still need to be investigated.

Thiemig, V.; Bisselink, B.; Pappenberger, F.; Thielen, J.

2014-05-01

320

Survivability of cosmological quark nuggets in the chromoelectric flux-tube fission model of baryon evaporation  

SciTech Connect

The question of the survivability of quark nuggets against the process of baryon evaporation from their surfaces is studied within the context of a dynamical model, namely, the chromoelectric flux-tube fission model of baryon formation and evaporation. Depending on the temperature at which nuggests are formed in the early Universe and the value of the bag constant [ital B], our conservative estimates (we overestimate the baryon evaporation rate) show that quark nuggets with an initial baryon number [similar to]10[sup 44] or more can survive the evaporation process and be present in the Universe today.

Bhattacharjee, P. (Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Calcutta-700 064 (India) Indian Institute of Astrophysics, Bangalore-560 034 (India)); Alam, J. (Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Calcutta-700 064 (India)); Sinha, B. (Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Calcutta-700 064 (India) Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Calcutta-700 064 (India)); Raha, S. (Bose Institute, 93/1 A.P.C. Road, Calcutta-700 009 (India))

1993-11-15

321

Some problems related to the performance of an evaporator as a vapor delivery system  

NASA Astrophysics Data System (ADS)

The complex interaction among the thermodynamic and transport characteristics of an evaporator used as a vapor delivery system is explored in a steady-state model. An example is presented which show how one may calculate the operating temperature required to yield a specified delivery rate, as a function of vapor pressure of the liquid, and the conductance of the flow path downstream of the evaporator. Under some conditions, liquid droplets may be entrained with the vapor flow. A model is presented for the distance downstream of the evaporator required for evaporation of these droplets.

Middleman, Stanley

1991-10-01

322

Evaporation of thorium from carburized thoriated tungsten cathodes  

Microsoft Academic Search

The evaporation of thorium from carburized thoriated tungsten cathodes is shown experimentally to be approximately the same as that from similar uncarburized cathodes at the same temperature. The thorium in a carburized cathode is, however, produced continuously at an adequate rate at the operating temperature of 2000 K by reduction of the thoria by the tungsten carbide. The uncarburized cathode

R O Jenkins; W G Trodden

1959-01-01

323

A diagram to determine the evaporation status of extrasolar planets  

NASA Astrophysics Data System (ADS)

Aims:To describe the evaporation status of extrasolar planets, we consider an energy diagram in which the potential energy of the planets is plotted versus the energy received by the upper atmosphere. Methods: Here we present a basic method to estimate these quantities. For the potential energy, we include the modification of the gravity field by the tidal forces from the parent stars. Results: This description allows a rapid estimate of both the escape rate of the atmospheric gas and the lifetime of a planet against the evaporation process. In the energy diagram, we find an evaporation-forbidden region in which a gaseous planet would evaporate in less than 5 billion years. With their observed characteristics, all extrasolar planets are found outside this evaporation-forbidden region. The escape rates are estimated to be in the range 105 g s-1 to 1012 g s-1, with a few cases above 1011 g s-1. The estimated escape rate for HD 209458 b is consistent with the lower limit of 1010 g s-1 obtained from interpretation of the H i Lyman-? observations. This diagram suggests possibilities for the nature of the recently discovered Neptune-mass planets. We find that GJ 436 b, 55 Cnc e and HD 69830 b cannot be low mass gaseous planets. With a density that must be above 0.5 g cm-3 to survive evaporation, these planets must contain a large fraction of solid/liquid material. We find that GJ 876 d must have a density greater than ~3 g cm-3 to survive the strong EUV energy flux from its nearby parent star. GJ 876 d must contain a large fraction of massive elements.

Lecavelier Des Etangs, A.

2007-01-01

324

Kinetics of evaporation of forsterite and Fe-Mg olivine in vacuum  

Microsoft Academic Search

Evaporation of forsterite, which plays an important role in chemical and isotope fractionation in the early solar nebula, is governed by surface kinetics strongly affected by surface conditions, such as surface roughness as well as density and orientation of dislocation outcrops. We have revealed anisotropies in evaporation rate and surface microstructure of forsterite and Fe-Mg olivine [1-3]. In order to

K. Ozawa; H. Nagahara

2009-01-01

325

Dynamics of soil water evaporation during soil drying: laboratory experiment and numerical analysis.  

PubMed

Laboratory and numerical experiments were conducted to investigate the evolution of soil water evaporation during a continuous drying event. Simulated soil water contents and temperatures by the calibrated model well reproduced measured values at different depths. Results show that the evaporative drying process could be divided into three stages, beginning with a relatively high evaporation rate during stage 1, followed by a lower rate during transient stage and stage 2, and finally maintaining a very low and constant rate during stage 3. The condensation zone was located immediately below the evaporation zone in the profile. Both peaks of evaporation and condensation rate increased rapidly during stage 1 and transition stage, decreased during stage 2, and maintained constant during stage 3. The width of evaporation zone kept a continuous increase during stages 1 and 2 and maintained a nearly constant value of 0.68?cm during stage 3. When the evaporation zone totally moved into the subsurface, a dry surface layer (DSL) formed above the evaporation zone at the end of stage 2. The width of DSL also presented a continuous increase during stage 2 and kept a constant value of 0.71?cm during stage 3. PMID:24489492

Han, Jiangbo; Zhou, Zhifang

2013-01-01

326

Simultaneously Maintaining the Complementary Relationship and the Conservation of Evaporative Fraction During the Daytime  

NASA Astrophysics Data System (ADS)

The Complementary Relationship CR between actual and potential evaporation and the self-preservation of the evaporative fraction EF during the daytime have both been extensively explored and applied. The CR says that increases in potential evaporation Ep (e.g., pan evaporation or evaporation from Penman's equation) above the wet surface value E0, indicate decreases in actual regional evaporation E. That is, as the regional surface dries, regional evaporation E decreases, leading to drier, warmer air and higher potential evaporation Ep. This fact can be used (e.g., in the Advection-Aridity approach, AA) to estimate regional evaporation E knowing only available energy (Rn-G, where Rn is net radiation and G is ground heat flux) and measurements at one height of wind speed, temperature and humidity. Self-preservation of EF means that EF [LE/(Rn-G), where LE is the latent heat flux] tends to remain relatively constant during much of the daytime on a single day. Thus a single daytime estimate of EF can be used to estimate daily or daytime total evaporation if daytime available energy is known. CR and self-preservation of EF are both supported by substantial empirical evidence under a range of 'typical' conditions. Yet, no definitive proof of either concept has been found--they remain intuitive concepts. Their usefulness as concepts is that they help researchers to develop a mental framework of the evaporation process, at the same time providing a powerful way to leverage sparse data. To explore how the two concepts work together on a single day, a 3-dimensional surface representing dimensionless E is developed based on the Penman-Monteith equation. Lines corresponding to constant EF and to the AA equation can be traced along the evaporation surface. Since these two lines do not follow the same trajectory, simultaneously following the AA trajectory and maintaining a constant EF during a day on which weather conditions are constantly changing seems problematic. However, a slightly different graph shows that trajectories exist for which EF is constant and the AA equation is maintained, even as weather conditions change. Thus, conservation of EF and the CR are compatible concepts. A case study using field data illustrates these concepts.

Crago, R. D.; Qualls, R. J.

2013-12-01

327

Evaporators with hydrophobic heat-transfer agents  

Microsoft Academic Search

Contact evaporators with HHTAs differ from other types of evaporators by their simplicity of construction. They can also be used to capture waste heat from exit gases coming from industrial furnaces. A column type apparatus was proposed as an evaporator with a HHTA in which the heated heat-transfer agent is atomized into drops in order to create a large surface

A. G. Konnov; P. G. Udyma

1992-01-01

328

Carbothermal synthesis of boron nitride coating on PAN carbon fiber  

Microsoft Academic Search

Boron nitride (BN) thin coating has been formed on the surface of chemically activated polyacrylonitrile (PAN) carbon fiber by dip coating method. Dip coating was carried out in saturated boric acid solution followed by nitridation at a temperature of 1200C in nitrogen at atmospheric pressure to produce BN coating. Chemical activation improved surface area of PAN fiber which favours in

M. Das; A. K. Basu; S. Ghatak; Amish G. Joshi

2009-01-01

329

Atmospheric peroxyacetyl nitrate (PAN): a global budget and source attribution  

NASA Astrophysics Data System (ADS)

Peroxyacetyl nitrate (PAN) formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) is the principal tropospheric reservoir for nitrogen oxide radicals (NOx = NO + NO2). PAN enables the transport and release of NOx to the remote troposphere with major implications for the global distributions of ozone and OH, the main tropospheric oxidants. Simulation of PAN is a challenge for global models because of the dependence of PAN on vertical transport as well as complex and uncertain NMVOC sources and chemistry. Here we use an improved representation of NMVOCs in a global 3-D chemical transport model (GEOS-Chem) and show that it can simulate PAN observations from aircraft campaigns worldwide. The immediate carbonyl precursors for PAN formation include acetaldehyde (44% of the global source), methylglyoxal (30%), acetone (7%), and a suite of other isoprene and terpene oxidation products (19%). A diversity of NMVOC emissions is responsible for PAN formation globally including isoprene (37%) and alkanes (14%). Anthropogenic sources are dominant in the extratropical Northern Hemisphere outside the growing season. Open fires appear to play little role except at high northern latitudes in spring, although results are very sensitive to plume chemistry and plume rise. Lightning NOx is the dominant contributor to the observed PAN maximum in the free troposphere over the South Atlantic.

Fischer, E. V.; Jacob, D. J.; Yantosca, R. M.; Sulprizio, M. P.; Millet, D. B.; Mao, J.; Paulot, F.; Singh, H. B.; Roiger, A.; Ries, L.; Talbot, R. W.; Dzepina, K.; Pandey Deolal, S.

2014-03-01

330

Southern California Air Quality Study: Peroxyacetyl Nitrate (PAN) Measurements.  

National Technical Information Service (NTIS)

Measurements of peroxyacetyl nitrate (PAN) have been carried out as part of the 1987 Southern California Air Quality Study. While PAN has long been observed in Southern California air, the authors study yielded for the first time information on the spatia...

E. L. Williams D. Grosjean

1989-01-01

331

A Pan-Indigenous Vision of Indigenous Studies.  

ERIC Educational Resources Information Center

Identifies four groups with conflicting interests in indigenous studies programs and the nature of the conflicts. Proposes the formation of a pan-indigenous intellectual network. Describes the ideal indigenous studies program devoted to building a pan-indigenous infrastructure that indigenous nations would direct and use as a tool to strengthen

Masaquiza, Martina; B'alam, Pakal

2000-01-01

332

Pan-Sharpening Using an Adaptive Linear Model  

Microsoft Academic Search

In this paper, we propose an algorithm to synthesize high-resolution multispectral images by fusing panchromatic (Pan) images and multispectral (MS) images. The algorithm is based on an adaptive linear model, which is automatically estimated by least square fitting. In this model, a virtual difference band is appended to the MS to guarantee the correlation between the Pan and MS. Then,

Lining Liu; Yiding Wang; Yunhong Wang; Haiyan Yu

2010-01-01

333

Evaporation by mechanical vapor recompression  

NASA Astrophysics Data System (ADS)

Progress in the development of a study of the application of the technologies of mechanical vapor recompression and falling film evaporation as applied to the beet sugar industry is reported. Progress is reported in the following areas: technical literature search; report on visit to European factories using these technologies; energy balance studies of factories offered by the industry as candidates for the demonstration plants; and report on energy balance studies and the recommendations as to the site for the demonstration plant.

Iverson, C. H.; Coury, G. E.

1980-04-01

334

Influence of Oil on Refrigerant Evaporator Performance  

NASA Astrophysics Data System (ADS)

To explore the quantitative effect of the lubrication oil on the thermal and hydraulic evaporator performance, the detailed structure of two-phase refrigerant (R11) and lubrication oil (Suniso 5GS) flow has been investigated. Experiment has been performed using a transparent tube 20mm in inner diameter and 2600mm in total length as main test section, which was heated by surrounding hot water bath. This water bath also functioned as the visual observation section of the transition of two-phase flow pattern. Oil mass concentration was controlled initially, and circulated into the system. The void fraction at the main test section was measured by direct volume measurement using so-called "Quick Closing Valve" method. Since the effect of oil on the transition of two-phase flow pattern is emphasized at the low flow rate, operation was made at relatively low mass velocity, 50 and 100 kg/m2s, five different oil concentrations were taken. Throughout the experiment, the evaporation pressure was kept at 105 kPa. In general, when contamination of the lubrication oil happened, the void fraction was decreasing due to the change of viscosity and surface tension and the occurence of the foaming. To correlate the void fraction as function of quality, Zivi's expression was modified to include the effect of oil concentration. The agreement between the data and this proposed correlation was favorable. Finally, to take into account the effect of lubrication oil, the new flow pattern diagram was proposed.

Jong-Soo, Kim; Nagata, Katsuya; Katsuta, Masafumi; Tomosugi, Hiroyuki; Kikuchi, Kouichiro; Horichi, Toshiaki

335

Identification of PAN2 by quantitative proteomics as a leucine-rich repeat-receptor-like kinase acting upstream of PAN1 to polarize cell division in maize.  

PubMed

Mechanisms governing the polarization of plant cell division are poorly understood. Previously, we identified pangloss1 (PAN1) as a leucine-rich repeat-receptor-like kinase (LRR-RLK) that promotes the polarization of subsidiary mother cell (SMC) divisions toward the adjacent guard mother cell (GMC) during stomatal development in maize (Zea mays). Here, we identify pangloss2 (PAN2) as a second LRR-RLK promoting SMC polarization. Quantitative proteomic analysis identified a PAN2 candidate by its depletion from membranes of pan2 single and pan1;pan2 double mutants. Genetic mapping and sequencing of mutant alleles confirmed the identity of this protein as PAN2. Like PAN1, PAN2 has a catalytically inactive kinase domain and accumulates in SMCs at sites of GMC contact before nuclear polarization. The timing of polarized PAN1 and PAN2 localization is very similar, but PAN2 acts upstream because it is required for polarized accumulation of PAN1 but is independent of PAN1 for its own localization. We find no evidence that PAN2 recruits PAN1 to the GMC contact site via a direct or indirect physical interaction, but PAN2 interacts with itself. Together, these results place PAN2 at the top of a cascade of events promoting the polarization of SMC divisions, potentially functioning to perceive or amplify GMC-derived polarizing cues. PMID:23175742

Zhang, Xiaoguo; Facette, Michelle; Humphries, John A; Shen, Zhouxin; Park, Yeri; Sutimantanapi, Dena; Sylvester, Anne W; Briggs, Steven P; Smith, Laurie G

2012-11-01

336

Token transfers among great apes (Gorilla gorilla, Pongo pygmaeus, Pan paniscus, and Pan troglodytes): species differences, gestural requests, and reciprocal exchange.  

PubMed

Great apes appear to be the nonhuman primates most capable of recognizing trading opportunities and engaging in transfers of commodities with conspecifics. Spontaneous exchange of goods between them has not yet been reported. We tested gorillas (Gorilla gorilla), orangutans (Pongo pygmaeus), bonobos (Pan paniscus), and chimpanzees (Pan troglodytes) in a token-exchange task involving two conspecifics and a human experimenter. Tested in pairs, subjects had to exchange tokens with a partner to obtain food from the experimenter. We observed 4, 5, 264, and 328 transfers of tokens in gorillas, chimpanzees, orangutans, and bonobos, respectively. Most gifts were indirect in gorillas, chimpanzees, and bonobos, whereas most were direct in orangutans. The analysis showed no evidence of calculated reciprocity in interactions. A main finding of the study was the high rate of repeated gifts and begging gestures recorded in orangutans. This raises the question of the meaning of pointing in great apes and their ability to understand the communicative intent of others. PMID:19929106

Pel, Marie; Dufour, Valrie; Thierry, Bernard; Call, Josep

2009-11-01

337

Fabrication of Micropatterns using Salt Crystals from Solvent Evaporation  

NASA Astrophysics Data System (ADS)

Herein, we investigated the crystallization behaviors of sodium carbonate (Na2CO3) from highly diluted aqueous solutions. Aqueous Na2CO3 solutions which were applied on substrate surfaces by either dropping or draining exhibited a variety of well-defined crystal structures over large areas during water evaporation. It was also found that both sizes and shapes of salt crystals could be effectively controlled by the experimental conditions such as their concentration, evaporation rate, temperature and humidity. Furthermore, it was observed that the salt crystals could be oriented to specific direction as the evaporation of water occurred on the tilted substrates. The crystals of Na2CO3were then employed as the master pattern to fabricate the soft mold of poly(dimethyl siloxane) (PDMS). Then silver (Ag) inks were filled into the pores of PDMS molds and transferred to various substrates by imprinting techniques to produce electrically conductive electrodes for potential electric devices.

Lee, Dong-Eun; Go, Seung Jae; Lee, Dong Hyun

2013-03-01

338

PEP725 Pan European Phenological Database  

NASA Astrophysics Data System (ADS)

PEP725 is a 5 years project with the main object to promote and facilitate phenological research by delivering a pan European phenological database with an open, unrestricted data access for science, research and education. PEP725 is funded by EUMETNET (the network of European meteorological services), ZAMG and the Austrian ministry for science & research bm:w_f. So far 16 European national meteorological services and 7 partners from different nati-onal phenological network operators have joined PEP725. The data access is very easy via web-access from the homepage www.pep725.eu. Ha-ving accepted the PEP725 data policy and registry the data download can be done by different criteria as for instance the selection of a specific plant or all data from one country. At present more than 300 000 new records are available in the PEP725 data-base coming from 31 European countries and from 8150 stations. For some more sta-tions (154) META data (location and data holder) are provided. Links to the network operators and data owners are also on the webpage in case you have more sophisticated questions about the data. Another objective of PEP725 is to bring together network-operators and scientists by organizing workshops. In April 2012 the second of these workshops will take place on the premises of ZAMG. Invited speakers will give presentations spanning the whole study area of phenology starting from observations to modelling. Quality checking is also a big issue. At the moment we study the literature to find ap-propriate methods.

Koch, E.; Lipa, W.; Ungersbck, M.; Zach-Hermann, S.

2012-04-01

339

Evaporation as the transport mechanism of metals in arid regions.  

PubMed

Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high evaporation rates in arid regions, groundwater quality is not threatened and all soil contamination issues tend to be overlooked. But if soil contamination happens, where do contaminants go? This study tests the hypothesis of upward metal movement in soils when evaporation is the main transport mechanism. Laboratory evaporation tests were carried out with heavy metal spiked Saudi soil, using circulation of air as the driving force (Fig. 1). Main results show that loamy soil retains heavy metals quite well while evaporation drives heavy metals to the surface of a sandy soil. Evaporation transports heavy metals upward in sandy soils of arid regions, making them accumulate at the soil surface. Sand being the dominating type of soil in arid regions, soils can then be a potential source of contaminated aerosols and atmospheric pollution - a transboundary problem. Some other repercussions for this problem are foreseen, such as the public ingestion or inhalation of dust. PMID:24997976

Lima, Ana T; Safar, Zeinab; Loch, J P Gustav

2014-09-01

340

Influence of electron evaporative cooling on ultracold plasma expansion  

SciTech Connect

The expansion of ultracold neutral plasmas (UCP) is driven primarily by the thermal pressure of the electron component and is therefore sensitive to the electron temperature. For typical UCP spatial extents, evaporative cooling has a significant influence on the UCP expansion rate at lower densities (less than 10{sup 8}/cm{sup 3}). We studied the effect of electron evaporation in this density range. Owing to the low density, the effects of three-body recombination were negligible. We modeled the expansion by taking into account the change in electron temperature owing to evaporation as well as adiabatic expansion and found good agreement with our data. We also developed a simple model for initial evaporation over a range of ultracold plasma densities, sizes, and electron temperatures to determine over what parameter range electron evaporation is expected to have a significant effect. We also report on a signal calibration technique, which relates the signal at our detector to the total number of ions and electrons in the ultracold plasma.

Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)] [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

2013-07-15

341

Membrane-Based Water Evaporator for a Space Suit  

NASA Technical Reports Server (NTRS)

A membrane-based water evaporator has been developed that is intended to serve as a heat-rejection device for a space suit. This evaporator would replace the current sublimator that is sensitive to contamination of its feedwater. The design of the membrane-based evaporator takes advantage of recent advances in hydrophobic micropore membranes to provide robust heat rejection with much less sensitivity to contamination. The low contamination sensitivity allows use of the heat transport loop as feedwater, eliminating the need for the separate feedwater system used for the sublimator. A cross section of the evaporator is shown in the accompanying figure. The space-suit cooling loop water flows into a distribution plenum, through a narrow annulus lined on both sides with a hydrophobic membrane, into an exit plenum, and returns to the space suit. Two perforated metal tubes encase the membranes and provide structural strength. Evaporation at the membrane inner surface dissipates the waste heat from the space suit. The water vapor passes through the membrane, into a steam duct and is vented to the vacuum environment through a back-pressure valve. The back-pressure setting can be adjusted to regulate the heat-rejection rate and the water outlet temperature.

Ungar, Eugene K.; McCann, Charles J.; O'Connell, Mary K.; Andrea, Scott

2004-01-01

342

Evaporator Development for an Evaporative Heat Pipe System  

NASA Technical Reports Server (NTRS)

As fossil fuel resources continue to deplete, research for alternate power sources continues to develop. One of these alternate technologies is fuel cells. They are a practical fuel source able to provide significant amounts of power for applications from laptops to automobiles and their only byproduct is water. However, although this technology is over a century old and NASA has been working with it since the early 1960 s there is still room for improvement. The research I am involved in at NASA's Glenn Research Center is focusing on what is called a regenerative fuel cell system. The unique characteristic of this type of system is that it used an outside power source to create electrolysis of the water it produces and it then reuses the hydrogen and oxygen to continue producing power. The advantage of this type of system is that, for example, on space missions it can use solar power to recharge its gas supplies between periods when the object being orbited blocks out the sun. This particular system however is far from completion. This is because of the many components that are required to make up a fuel cell that need to be tested individually. The specific part of the system that is being worked on this summer of 2004 is the cooling system. The fuel cell stack, that is the part that actually creates the power, also produces a lot of heat. When not properly cooled, it has been known to cause fires which, needless to say are not conducive to the type of power that is trying to be created. In order to cool the fuel cell stack in this system we are developing a heat pipe cooling system. One of the main components of a heat pipe cooling system is what is known as the evaporator, and that is what happens to be the part of the system we are developing this summer. In most heat pipe systems the evaporator is a tube in which the working fluid is cooled and then re-circulated through the system to absorb more heat energy from the fuel cell stack. For this system, instead of a tube, the evaporator is made up of a stack-up of screen material and absorbent membranes inside a stainless steel shell and held together by a film adhesive and epoxy. There is an initial design for this flat plate evaporator, however is has not yet been made. The components of the stack-up are known, so all testing is focused on how it will all go together. This includes finding an appropriate epoxy to make the evaporator conductive all the way through and finding a way to hold the required tight tolerances as the stainless steel outer shell is put together. By doing the tests on smaller samples of the stack-ups and then testing the fill size component, the final flat plate evaporator will reach its final design so that research can continue on other parts of the regenerative fue1 cell system, and another step in the improvement of fue1 cell technology can be made.

Peters, Leigh C.

2004-01-01

343

Shaping Titan's Landscapes by Dissolution and Evaporation: The Case of Ontario Lacus, a High-Latitude Semi-Arid Karst-Playa Landsystem  

NASA Astrophysics Data System (ADS)

The comparison between Ontario Lacus (Titan) and the Etosha Pan (Namibia), a semi-arid karst-playa landsystem, infer that dissolution/evaporation processes shaped Ontario Lacus' region until the present day, and perhaps as a whole, other Titan's lakes.

Cornet, T.; Bourgeois, O.; Le Moulic, S.; Rodriguez, S.; Sotin, C.; Lefvre, A.; Barnes, J. W.; Brown, R. H.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P. D.

2012-03-01

344

Dynamics of transition from stage-1 to stage-2 evaporation from porous media  

NASA Astrophysics Data System (ADS)

The early stages of evaporation from porous media are marked by a relatively high and constant evaporation rate (the so-called stage-1 evaporation) sustained by capillary liquid flow from the porous medium interior. Following interruption of hydraulic connections at a certain drying front depth, the vaporization plane migrates below the surface leading to transition to stage-2 evaporation limited by vapour diffusion through the porous medium. The nature of the transition and the wide range of transition dynamics from stage-1 to stage-2 were studied using evaporation experiments from sand-filled Hele-Shaw cells (172x81x4 mm) with three mean particle sizes of 0.27, 0.46, and 0.84 mm. The initially water saturated cells were placed on digital balances (cell top exposed to air) to record evaporation rates. Experiments were conducted in an environmental chamber where the relative humidity and temperature could be varied and controlled accurately. The effects of grains size, ambient temperature and relative humidity (both affecting potential evaporation rates) on transition dynamics were systematically evaluated. The results illustrate the role of potential evaporation rate on transition duration and shape transcending the expected scaling with cumulative mass loss that defines the evaporative characteristic length. The transition becomes more abrupt at higher atmospheric demand perhaps due to enhanced role of viscous effects that accelerate pore disconnection. Pore size did not affect the shape of transition much except for the medium sand with prolonged transition (the exact pore size distribution needs to be examined). Interestingly the evaporation rate at the onset of stage 2 was not affected by atmospheric conditions (Shokri and Or, 2011).

Shokri, Nima; Shahraeeni, Ebrahim; Shahabdeen, Rumeena; Or, Dani

2014-05-01

345

Evaporation for Lithium Bromide Aqueous Solution in a Falling Film Heater under Reduced Pressures  

NASA Astrophysics Data System (ADS)

Experiments on evaporation for water and lithium bromide (LiBr) aqueous solution were made in a externally heated wetted-wall column under reduced pressures. For water, evaporation rate increased slightly as feed rate decreased. The heat transfer coefficients of falling film agreed with those for filmwise condensation. For LiBr solution, evaporation rate decreased and outlet temperature of LiBr solution increased as feed rate decreased. The equations of continuity, diffusion and energy which assume that only water moves to the surface and LiBr doesn't move through falling film of LiBr solution were solved numerically. Calculated values of evaporation rate and outlet temperature of solution agreed with experimental results. The results of this work were compared with pool boiling data reported previously, and it was shown that falling film heater is superior to pool boiling heater concerning heat transfer.

Matsuda, Akira; Ide, Tetsuo; Yukino, Keiji

346

An Investigation of Electrochemomechanical Actuation of Conductive Polyacrylonitrile (PAN) Nanofiber Composites  

NASA Astrophysics Data System (ADS)

A polymer-based nanofiber composite actuator designed for linear actuation was fabricated by electrospinning, actuated by electrolysis, and characterized by electrical and mechanical testing to address performance limitations and understand the activation processing effects on actuation performance. Currently, Electroactive polymers (EAPs) have provided uses in sensory and actuation technology, but have either low force output or expand rather than contract, falling short in capturing the natural motion and function of muscle desperately needed to provide breakthroughs in the bio-medical and robotic fields. Previous research has shown activated Polyacrylonitrile (PAN) fibers having biomimetic functionalities similar to the sarcomere contraction responsible for muscle function. Activated PAN is also known to contract and expand by electrolysis when in close vicinity to the anode and cathode, respectively. PAN nanofibers especially show faster response to changes in environmental pH and improved mechanical properties over larger diameter fibers. Conductive additives were introduced to the electrospinning solution and activated in an attempt to create composite PAN nanofiber gel actuators with improved conductivity and eliminate the need of stiff electrodes. Tensile testing was conducted to examine changes in mechanical properties between annealing and hydrolysis processing. Introducing conductive additives did not show a significant increase in conductivity and created unusable samples, requiring alternative electrode materials. Electrochemical contraction rates up to 25%/ min were achieved. Strains of 58.8%, ultimate stresses up to 77.1 MPa, and moduli of 0.21 MPa were achieved with pure PAN nanofiber mats, surpassing mechanical properties of natural muscles. Improvements to contraction rates and young's moduli are necessary to capture the function and performance of skeletal muscles properly.

Gonzalez, Mark A.

347

Evaporation Estimation of Rift Valley Lakes: Comparison of Models  

PubMed Central

Evapotranspiration (ET) accounts for a substantial amount of the water flux in the arid and semi-arid regions of the World. Accurate estimation of ET has been a challenge for hydrologists, mainly because of the spatiotemporal variability of the environmental and physical parameters governing the latent heat flux. In addition, most available ET models depend on intensive meteorological information for ET estimation. Such data are not available at the desired spatial and temporal scales in less developed and remote parts of the world. This limitation has necessitated the development of simple models that are less data intensive and provide ET estimates with acceptable level of accuracy. Remote sensing approach can also be applied to large areas where meteorological data are not available and field scale data collection is costly, time consuming and difficult. In areas like the Rift Valley regions of Ethiopia, the applicability of the Simple Method (Abtew Method) of lake evaporation estimation and surface energy balance approach using remote sensing was studied. The Simple Method and a remote sensing-based lake evaporation estimates were compared to the Penman, Energy balance, Pan, Radiation and Complementary Relationship Lake Evaporation (CRLE) methods applied in the region. Results indicate a good correspondence of the models outputs to that of the above methods. Comparison of the 1986 and 2000 monthly lake ET from the Landsat images to the Simple and Penman Methods show that the remote sensing and surface energy balance approach is promising for large scale applications to understand the spatial variation of the latent heat flux.

Melesse, Assefa M.; Abtew, Wossenu; Dessalegne, Tibebe

2009-01-01

348

Steam oxidation and chromia evaporation in ultrasupercritical steam boilers and turbines  

SciTech Connect

The U.S. Department of Energy's goals include power generation from coal at 60% efficiency, which requires steam conditions of up to 760 {sup o}C and 340 atm, so-called ultrasupercritical conditions. Evaporation of protective chromia scales is a primary corrosion mechanism. A methodology to calculate Cr evaporation rates from chromia scales was developed and combined with Cr diffusion calculations within the alloy (with a constant flux of Cr leaving the alloy from evaporation) to predict Cr concentration profiles and to predict the time until breakaway oxidation. At the highest temperatures and pressures, the time until breakaway oxidation was quite short for the turbine blade, and of concern within the steam pipe and the higher temperature portions of the superheater tube. Alloy additions such as Ti may allow for a reduction in evaporation rate with time, mitigating the deleterious effects of chromia evaporation.

Holcomb, G.R. [US DOE, Albany, OR (United States)

2009-07-01

349

Volumetric and Lateralized Differences in Selected Brain Regions of Chimpanzees (Pan troglodytes) and Bonobos (Pan paniscus)  

PubMed Central

The two species of Pan, bonobos and common chimpanzees, have been reported to have different social organization, cognitive and linguistic abilities and motor skill, despite their close biological relationship. Here, we examined whether bonobos and chimpanzee differ in selected brain regions that may map to these different social and cognitive abilities. Eight chimpanzees and eight bonobos matched on age, sex and rearing experiences were magnetic resonance images scanned and volumetric measures were obtained for the whole brain, cerebellum, striatum, motor-hand area, hippocampus, inferior frontal gyrus and planum temporale. Chimpanzees had significantly larger cerebellum and borderline significantly larger hippocampus and putamen, after adjusting for brain size, compared with bonobos. Bonobos showed greater leftward asymmetries in the striatum and motor-hand area compared with chimpanzees. No significant differences in either the volume or lateralization for the so-called language homologs were found between species. The results suggest that the two species of Pan are quite similar neurologically, though some volumetric and lateralized differences may reflect inherent differences in social organization, cognition and motor skills.

Hopkins, William D.; Lyn, Heidi; Cantalupo, Claudio

2009-01-01

350

Spontaneous triadic engagement in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes).  

PubMed

Humans are believed to have evolved a unique motivation to participate in joint activities that first develops during infancy and supports the development of shared intentionality. We conducted five experiments with bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) (Total n = 119) to assess their motivation to spontaneously participate in joint activities with a conspecific or a human. We found that even the youngest subjects preferred to interact together with a human and a toy rather than engaging in an identical game alone. In addition, we found that subjects could spontaneously interact with a human in a turn-taking game involving passing a ball back and forth and used behaviors to elicit additional interaction when the game was disrupted. However, when paired with a conspecific, subjects preferred to interact with an object individually rather than together. Our results indicate that nonhuman apes are motivated to engage in triadic activities if they occur spontaneously with humans and require a minimum amount of coordination. These findings leave open the question of whether these activities are coordinated through shared intentions. PMID:23339560

MacLean, Evan; Hare, Brian

2013-08-01

351

Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) quantify split solid objects.  

PubMed

Recent research suggests that gorillas' and orangutans' object representations survive cohesion violations (e.g., a split of a solid object into two halves), but that their processing of quantities may be affected by them. We assessed chimpanzees' (Pan troglodytes) and bonobos' (Pan paniscus) reactions to various fission events in the same series of action tasks modelled after infant studies previously run on gorillas and orangutans (Cacchione and Call in Cognition 116:193-203, 2010b). Results showed that all four non-human great ape species managed to quantify split objects but that their performance varied as a function of the non-cohesiveness produced in the splitting event. Spatial ambiguity and shape invariance had the greatest impact on apes' ability to represent and quantify objects. Further, we observed species differences with gorillas performing lower than other species. Finally, we detected a substantial age effect, with ape infants below 6 years of age being outperformed by both juvenile/adolescent and adult apes. PMID:22875724

Cacchione, Trix; Hrubesch, Christine; Call, Josep

2013-01-01

352

Optimization of Flow Coefficient for Pan Check Valve by Fluid Dynamic Analysis  

NASA Astrophysics Data System (ADS)

This paper describes the optimization of flow coefficient for pan check valve by computational fluid dynamic analysis. This work is focused on determine the length of supporting beam by pressure drop analysis and evaluate flow coefficient. And then in case of optimum design of pan check valve, predict flow head loss with different flow rate. The application of CFD method provided a greater insight into the flow visualization aspects throught this pan check valve. By using CFD analysis, pressure and velocity distribition can be easily observed and the pressure drop and flow coefficient can be exactly predicted. The lenght of supporting beam gives an important effect on the fluid performance of the check valve and the optimum length for the supporting beam is 32 mm, the pan disc supported at this distance yields the minimum pressure drop and maximum flow coefficient. This resarch improved the understanding of the fluid flow performance of check valve, the method can also be applied to optimize the other part of this valve and/or other different valves.

Lee, Joon-Ho; Song, Xue-Guan; Kang, San-Mo; Park, Young-Chul

2010-06-01

353

Pan-sharpening high spatial resolution ratio images using optimization  

NASA Astrophysics Data System (ADS)

Among most of current Pan-sharpening methods, resampling is generally required to make panchromatic (Pan) and multispectral (MS) images matched correctly pixel by pixel. However, few methods have focused on spectral distortions caused by shape distortions of real features during resampling. This paper proposes a new Pan-sharpening algorithm based on the gray and spectral relationships between Pan, MS and the fused images. In the algorithm, Pan-sharpening is defined as an optimization of a linear overdetermined system. It takes Pan and original MS images as input datasets without resampling. The Least square technique is applied to calculate the optimum values (quality fused images). QuickBird image datasets are tested, and the results are compared with the fused images of IHS, PCA and Gram-Schmidt using interpolated MS image. The result shows that the proposed method is more efficient than IHS, PCA and Gram-Schmidt in preserving spectral characteristics and increasing spatial resolution, especially for high spatial resolution ratio (SRR > 4:1, spatial resolution ratio is the ratio of the spatial resolution of MS image to that of Pan image.) images.

Li, Fangjun; Chen, Fu; Liu, Jianbo

2009-10-01

354

Summertime PAN on boundary layer over the Northern Pacific Ocean  

NASA Astrophysics Data System (ADS)

As a part of SHIPPO ( Shipborne Pole to Pole Observation), peroxyacetyl nitrate (PAN) and NO2 have been measured at aboard the R/V Araon during the ship track from Inchon, South Korea to Norm, Alaska, USA from July 14th to 30th, 2012. PAN and NO2 were sampled every 2 minute by a fast chromatograph with luminol-based chemiluminescence detection. In order to assure their detections in remote background airs, we successfully reduced random noise mainly from PMT using ensemble averaging from the 2 min chromatograms in each one hour time interval. With this post-processing analysis, we were able to lower detection limits to 0.01 ppbv and 0.04 ppbv for PAN and NO2, respectively. The preliminary results indicate that the background values ranged from the below the detection limit to 0.37 ppbv (average of 0.06 ppbv) for PAN and 2.05 ppbv (average of 0.24 ppbv) for NO2. It was confirmed that PAN was significant portions of reactive nitrogens in remote marine boundary airs. Occasional enhancements of PAN and NO2 were mainly attributed to the air masses originated from nearby source regions in the Northestern Asia and influenced by ships exhausts. We were able to observe the shifting of equilibrium between PAN and NO2 according to air temperature changes in very clean air masses.

Song, D.; Lee, S.; Lee, G.; Rhee, T. S.

2012-12-01

355

On the role of physiochemical properties on evaporation behavior of DISI biofuel sprays  

NASA Astrophysics Data System (ADS)

Biofuels and alternative fuels are increasingly being blended to conventional gasoline fuel to reduce the overall CO2 emissions. The effect on NOx and soot formation is still unclear as the atomization and evaporation of gasoline with biocomponents differ depending on fuel specific physiochemical properties. This work focuses on describing the biofuel evaporation behavior of gasoline sprays at homogeneous charge (early injection timing) and stratified-charge conditions (late injection timing mode) used in modern direct injection spark ignition engines (DISI). A spray plume of a 6-hole solenoid injector is analyzed in terms of liquid spray propagation, and local droplet sizes studied in an injection chamber. Depending on the operating conditions, different physiochemical properties are found to dominate the atomization and evaporation processes: For low and moderate ambient temperature and pressure, high-boiling point components show a strong influence on the spray droplet size distribution. However, at elevated temperature and pressure, the evaporation behavior changes completely. Due to a high degree of evaporation, the evaporation cooling effect dominates the local droplet sizes. Fuel mixtures owing a larger heat of vaporization show larger droplet sizeseven if these fuels have a lower boiling point. Depending on the local evaporation behavior, the different remaining droplet momentum in the spray controls the air entrainment and the subsequent progress of evaporation and mixing. Overall, it can be stated that the heat of vaporization is a dominating physiochemical property for the droplet evaporation rate at high-level supercharged conditions.

Knorsch, Tobias; Heldmann, Markus; Zigan, Lars; Wensing, Michael; Leipertz, Alfred

2013-06-01

356

Organic Evaporator steam valve failure  

SciTech Connect

DWPF Technical has requested an analysis of the capacity of the organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS).

Jacobs, R. A.

1992-09-29

357

Experimental and theoretical investigations of falling film evaporation  

NASA Astrophysics Data System (ADS)

In this study, a mathematical model was developed for falling film evaporation in vacuum using heat transfer relations. An experimental device was designed. experimental set-up which was used was equipped with a triangular weir distribution device and it had the ability to record data up to 3 m. Experiments were performed in a single-effect process with sucrose-water solution varying from 3 to 20% concentration rate of sucrose and we used a vertical tube evaporator with the dimensions of laboratory scale. The model that was developed considers convection, shear stress, viscosity and conjugate heat transfer while most of the previous works ignored these factors. The main factors influencing the heat transfer mechanism performance of the unit were investigated and analyzed. We concluded that the experimental studies are verified by the developed model. Furthermore, it was also concluded that, the heat transfer is affected by the mass flow rate, sucrose concentration rate in solution, film thickness and pressure.

Pehlivan, Hseyin; zdemir, Mustafa

2012-06-01

358

Testing of the Multi-Fluid Evaporator Engineering Development Unit  

NASA Technical Reports Server (NTRS)

Hamilton Sundstrand is under contract with the NASA Johnson Space Center to develop a scalable, evaporative heat rejection system called the Multi-Fluid Evaporator (MFE). It is being designed to support the Orion Crew Module and to support future Constellation missions. The MFE would be used from Earth sea level conditions to the vacuum of space. The current Shuttle configuration utilizes an ammonia boiler and flash evaporator system to achieve cooling at all altitudes. The MFE system combines both functions into a single compact package with significant weight reduction and improved freeze-up protection. The heat exchanger core is designed so that radial flow of the evaporant provides increasing surface area to keep the back pressure low. The multiple layer construction of the core allows for efficient scale up to the desired heat rejection rate. The full scale MFE prototype will be constructed with four core sections that, combined with a novel control scheme, manage the risk of freezing the heat exchanger cores. A sub-scale MFE engineering development unit (EDU) has been built, and is identical to one of the four sections of a full scale prototype. The EDU has completed testing at Hamilton Sundstrand. The overall test objective was to determine the thermal performance of the EDU. The first set of tests simulated how each of the four sections of the prototype would perform by varying the chamber pressure, evaporant flow rate, coolant flow rate and coolant temperature. A second set of tests was conducted with an outlet steam header in place to verify that the outlet steam orifices prevent freeze-up in the core while also allowing the desired thermal turn-down ratio. This paper discusses the EDU tests and results.

Quinn, Gregory; O'Connor, Ed; Riga, Ken; Anderson, Molly; Westheimer, David

2007-01-01

359

Investigation of evaporate deposits in the Great Ear area of Lop Nor salt plain, Xinjiang Province, China  

NASA Astrophysics Data System (ADS)

In arid regions of the world, salt pans are common features occupying the lowest areas of closed interior basin. The Lop Nor salt plain is located at the east end of the Tarim Basin, Xinjiang Province, China. Widespread Holocene salt deposits were known to cover thousands of square kilometers and up to hundreds of meters thick. However, the salt pans in the central-eastern sector of the Lop Nor salt plain is unusually represented by successive concentric black-and-white rings that closely resembled a big human ear in satellite images. The total area of the Great Ear is approximately 5,500 km2, and the internal morphology is considered essentially flat with an elevation of 800 m. A series of detailed field investigations on the Great Ear salt pans involved describing evaporates and surface morphologies, measuring chemical compositions, and groundwater depths. The deposits show clear lateral variations in salt content, water content, evaporate mineralogy, as well as the microrelief of salt crust in the Great Ear area. Spatially, spectral imaging variation corresponds to color variation in the Great Ear, which suggests surface moist conditions of a salt pan: dark-toned areas are wet and the bright-toned areas are dry. In the wet zone, capillary fringing of groundwater brines control the precipitation of evaporites and microrelief genesis. The salt pans are marked by pressure-ridge and well-developed hexagonal honeycomb polygons structures, where the microrelief of salt crust ranges from 30 to 80 cm. In the dry salt pans zone, groundwater discharge was not observed on the surface and the salt crust is characterized by low relief, low salinity, a lack of efflorescences crusts, and significant amounts of detrital sediments. This zone shows bright-tone in the satellite images due to higher reflectance of dry salt-encrusted pans surface. Though, the sediment beneath the surface typically is saturated with concentrated brines and displacive evaporites. The main minerals of evaporites are halite (NaCl), anhydrite (CaSO4), and gypsum (CaSO4. 2H2O) in the Great Ear salt pan. Other minerals like bischofite, picromerite were found on the surface of the wet salt pan zone due to discharge of concentrated groundwater brine. Conversely, carbonate minerals such as calcite and dolomite were identified on the dry salt pan zone accompanied by relatively higher abundances of gypsum, which is derived by fluvial and aeolian erosion and transport

Ma, L.; Li, B.; Jiang, P.; Lowenstein, T. K.; Zhong, J.; Sheng, J.; Wu, H.

2009-12-01

360

Numerical study of heat and mass transfer of ammonia-water in falling film evaporator  

NASA Astrophysics Data System (ADS)

To investigate the performance of the heat and mass transfer of ammonia water during the process of falling film evaporation in vertical tube evaporator, a mathematical model of evaporation process was developed and solved based on stream function. Then an experimental study of falling film evaporation was carried out in order to validate the mathematical model. A series of parameters, such as velocity, film thickness and concentration, etc., were obtained from the mathematical model. The calculated results show that the average velocity and the film thickness change sharp at the entrance region when x < 100 mm, while they vary slightly in the fully developed region when x > 100 mm. The film thickness depends largely on the flow rate of solution. It is observed that the heating power and mass flow of solution significantly affect the concentration difference between the inlet and outlet of evaporation tube. The calculated results reveal that the tube length has a significant impact on the amounts of ammonia vapor evaporated. It is suggested that the roll-worked enhanced tube should be used in order to decrease the concentration gradient in the film thickness direction and enhance the heat and mass transfer rate. Furthermore, the experimental and calculated results indicate that the inlet solution concentration has a great influence on the heat exchange capacity, the amounts of ammonia vapor evaporated and the evaporation pressure.

Bu, Xianbiao; Ma, Weibin; Huang, Yuanfeng

2012-05-01

361

Physical characterization of radioactive sludges in selected Melton Valley and evaporator facility storage tanks.  

National Technical Information Service (NTIS)

Physical measurements were performed on typical radioactive sludge samples from selected Melton Valley Storage Tanks (MVSTs) and evaporator facility storage tanks at ORNL. These measurements included viscosity, particle size, density, sedimentation rate, ...

R. N. Ceo M. B. Sears J. T. Shor

1990-01-01

362

Formation, levitation and evaporation of unsupported liquid fuel droplet clusters  

NASA Astrophysics Data System (ADS)

Evaporation and combustion experiments using arrays of droplets seek to provide a link between single droplet phenomena and the behavior of complex spray systems. Both single droplet and droplet array studies have been conducted in microgravity to better isolate the droplet interaction phenomena and eliminate or reduce the confounding effects of buoyancy-induced convection. In most experiments involving droplet arrays, the droplets are supported on fibers to keep them stationary and close together prior to combustion. The presence of the fiber, however, disturbs the combustion process by introducing a source of heat transfer and asymmetry into the configuration. As the number of drops in a droplet array increases, supporting the drops on fibers becomes less practical because of the cumulative effect of the fibers on the combustion process. In this thesis, recent works related to the single drop and droplet array evaporation and combustion, unsupported droplet and droplet cluster formation, and microgravity combustion experiments are reviewed. A unique experiment in which unsupported droplet clusters are formed in normal gravity has been developed and the design concepts and test results are presented and discussed. The results of droplet cluster formation and levitation tests and investigations of the acoustic field are also presented. The current 1-g equipment has been used to investigate the inter-droplet effects of a droplet cluster supported in an acoustic field. Droplet size, inter-droplet distance and evaporation rate were measured and compared with theoretical models. It was found that the single droplet evaporation results are consistent with previous studies and compared well with the single droplet evaporation models. Direct experimental results of multiple droplet evaporation were obtained and compared with a point source method. Based on the 1-g test results, the experimental apparatus will be incorporated into a drop tower rig where experiments can be performed in a microgravity environment.

Liu, Song

363

Evaporation of water droplets on soft patterned surfaces.  

PubMed

The evaporation process of a sessile drop of water on soft patterned polydimethylsiloxane (PDMS) substrates is investigated in this study. Different softness of a regular pillar-like patterned PDMS substrate can be achieved by controlling the mixing ratio of a PDMS's prepolymer base and a curing agent at 10?:?1, 20?:?1 and 30?:?1. The receding contact angle is smaller for softer pillar-like patterned substrates. Consequently, the evaporation rate is faster on softer pillar-like substrates. A sessile drop on the regular pillar-like PDMS substrates, prepared at the mixing ratio of a base to a curing agent of 10?:?1 and 20?:?1, is observed to start evaporating in the constant contact radius (CCR) mode then switching to the constant contact angle (CCA) mode via stepwise jumping of the contact line, and finally shifting to the mixed mode sequentially. During the evaporation, a wetting transition from the Cassie to the Wenzel state occurs earlier for the softer substrate because softer pillars relatively cannot stand the increasingly high Laplace pressure. For the softest regular pillar-like PDMS substrate prepared at the mixing ratio of the base to the curing agent of 30?:?1 (abbreviated by PDMS-30?:?1 substrate), the pillars collapse irreversibly after the sessile drop exhibits the wetting transition into the Wenzel state. Furthermore, it is interesting to find out that the initial stage of evaporation of a sessile drop on the PDMS-30?:?1 substrate in the Cassie state is in the CCR mode followed by the CCA mode with stepwise retreatment of the contact line. Further evaporation would induce the wetting transition from the Cassie to the Wenzel state (due to the collapse of pillars) and resume the CCR mode followed by the CCA mode again sequentially. PMID:24643481

Chuang, Yu-Chen; Chu, Che-Kang; Lin, Shih-Yao; Chen, Li-Jen

2014-05-21

364

Assessment of the Multi-Fluid Evaporator Technology  

NASA Astrophysics Data System (ADS)

Hamilton Sundstrand has developed a scalable evaporative heat rejection system called the Multi-Fluid Evaporator (MFE). It was designed to support the Orion Crew Module and to support future Constellation missions. The MFE would be used as a heat sink from Earth sea level conditions to the vacuum of space. The current shuttle configuration utilizes an ammonia boiler and water based flash evaporator system to achieve cooling at all altitudes. This system combines both functions into a single compact package with improved freeze-up protection. The heat exchanger core is designed so that radial flow of the evaporant provides increasing surface area to keep the back pressure low. The multiple layer construction of the core allows for efficient scale up to the desired heat rejection rate. A full-scale system uses multiple core sections that, combined with a novel control scheme, manage the risk of freezing the heat exchanger cores. A single-core MFE engineering development unit (EDU) was built in 2006, followed by a full scale, four-core prototype in 2007. The EDU underwent extensive thermal testing while the prototype was being built. Lessons learned from the EDU were incorporated into the prototype and proven out in check-out testing. The EDU and prototype testing proved out the MFE's ability to passively control back-pressure, avoid unwanted icing, tolerate icing if it should occur, provide a three-to-one turn down ratio in heat load and scale up efficiently. Some issues with these first designs of the MFE have limited its ability to reject heat without liquid evaporant carry-over. However, they are due to the implementation of the design rather than the fundamentals of the technology. This paper discusses the background, development and present state of the Multi-Fluid Evaporator technology and concludes with efforts underway to advance the state-of-the-art.

Quinn, Gregory; O'Connor, Edward

2008-01-01

365

PLS regression-based pan evaporation and minimummaximum temperature projections for an arid lake basin in India  

Microsoft Academic Search

Climate change information required for impact studies is of a much finer scale than that provided by Global circulation models\\u000a (GCMs). This paper presents an application of partial least squares (PLS) regression for downscaling GCMs output. Statistical\\u000a downscaling models were developed using PLS regression for simultaneous downscaling of mean monthly maximum and minimum temperatures\\u000a (T\\u000a max and T\\u000a min) as

Manish Kumar Goyal; C. S. P. Ojha

366

PLS regression-based pan evaporation and minimum-maximum temperature projections for an arid lake basin in India  

Microsoft Academic Search

Climate change information required for impact studies is of a much finer scale than that provided by Global circulation models (GCMs). This paper presents an application of partial least squares (PLS) regression for downscaling GCMs output. Statistical downscaling models were developed using PLS regression for simultaneous downscaling of mean monthly maximum and minimum temperatures ( T max and T min)

Manish Kumar Goyal; C. S. P. Ojha

2011-01-01

367

MANUAL SPOT WELDING STATION IN THE REAR PAN SCRAP REWORK ...  

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

MANUAL SPOT WELDING STATION IN THE REAR PAN SCRAP REWORK AREA FACING S. NORTH END OF HISTORIC PORTION OF ASSEMBLY PLANT, FIRST FLOOR, X7, COLUMN 17. - B Building, 3001 Miller Road, Dearborn, Wayne County, MI

368

12. Level 6 gringing pans, pump above dorr thickener. View ...  

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

12. Level 6 gringing pans, pump above dorr thickener. View to west. - Kennecott Copper Corporation, Concentration Mill, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

369

Pan Air Summary Document (Version 1.0).  

National Technical Information Service (NTIS)

The capabilities and limitations of the panel aerodynamics (PAN AIR) computer program system are summarized. This program uses a higher order panel method to solve boundary value problems involving the Prandtl-Glauert equation for subsonic and supersonic ...

T. Derbyshire K. W. Sidwell

1982-01-01

370

SWNT/PAN Composite Film based SuperCapacitors  

NASA Astrophysics Data System (ADS)

Activated carbon powder and activated carbon fiber, due to their high specific surface area, porous characteristics, relatively high electrical conductivity and good chemical resistance, have been extensively investigated as the electrode materials for an electrochemical supercapacitor. In the present study, a core-shell structured SWNT/Polyacrylonitrile (PAN) composite film has been produced with 30 nm in diameter SWNT bundles as the core and 10 nm thick PAN polymers as the shell. SEM was used to investigate the evolution of the porous structure of SWNT/PAN composite film induced by heat-treatment and CO2 activation process. These composite films possess advantages of SWNT as well as that of the activated carbon for the supercapacitor electrode. The constant charging and discharging experiments show that these activated SWNT/PAN composite films are very promising electrode materials for high capacitance and power performance.

Liu, Tao; Sreekumar, T. V.; Kumar, Satish; Hauge, Robert H.; Smalley, Richard E.

2003-03-01

371

Divergent Roles for Maize PAN1 and PAN2 Receptor-Like Proteins in Cytokinesis and Cell Morphogenesis1[W][OPEN  

PubMed Central

Pangloss1 (PAN1) and PAN2 are leucine-rich repeat receptor-like proteins that function cooperatively to polarize the divisions of subsidiary mother cells (SMCs) during stomatal development in maize (Zea mays). PANs colocalize in SMCs, and both PAN1 and PAN2 promote polarization of the actin cytoskeleton and nuclei in these cells. Here, we show that PAN1 and PAN2 have additional functions that are unequal or divergent. PAN1, but not PAN2, is localized to cell plates in all classes of dividing cells examined. pan1 mutants exhibited no defects in cell plate formation or in the recruitment or removal of a variety of cell plate components; thus, they did not demonstrate a function for PAN1 in cytokinesis. PAN2, in turn, plays a greater role than PAN1 in directing patterns of postmitotic cell expansion that determine the shapes of mature stomatal subsidiary cells and interstomatal cells. Localization studies indicate that PAN2 impacts subsidiary cell shape indirectly by stimulating localized cortical actin accumulation and polarized growth in interstomatal cells. Localization of PAN1, Rho of Plants2, and PIN1a suggests that PAN2-dependent cell shape changes do not involve any of these proteins, indicating that PAN2 function is linked to actin polymerization by a different mechanism in interstomatal cells compared with SMCs. Together, these results demonstrate that PAN1 and PAN2 are not dedicated to SMC polarization but instead play broader roles in plant development. We speculate that PANs may function in all contexts to regulate polarized membrane trafficking either directly or indirectly via their influence on actin polymerization.

Sutimantanapi, Dena; Pater, Dianne; Smith, Laurie G.

2014-01-01

372

The Design of the Pan-STARRS Telescope #1  

Microsoft Academic Search

The Pan-STARRS project at the University of Hawaii Institute for Astronomy has recently begun commissioning a 1.8m Cassegrain telescope with a 7 square degree field of view at the Haleakala summit on Maui. This telescope is known as PS1, and is a prototype for the four optical subsystems comprising the final Pan-STARRS (PS4). For this wide field application, the optical

J. Morgan; W. Siegmund; C. Hude

2006-01-01

373

Application of Taguchi method for the optimization of system parameters of centrifugal evaporative air cooler  

NASA Astrophysics Data System (ADS)

A new evaporative cooling system based on the action of centrifugal forces is proposed. Such systems are suitable for cooling large air volumes in tropical climates. Effects of geometrical and operational parameters on system performance are optimized using Taguchi method. It is observed that disc speed, air flow rate and water flow rate are found to have major influence on system performance and other parameter, viz., disc diameter, pin geometry, evaporation chamber length and orientation of pin have less influence.

Senthilkumar, K.; Srinivasan, Pss.

2010-10-01

374

Well logging evaporative thermal protection system  

SciTech Connect

An evaporative thermal protection system for use in hostile environment well logging applications, the system including a downhole thermal protection cartridge disposed within a well logging sonde or tool to keep a payload such as sensors and support electronics cool, the cartridge carrying either an active evaporative system for refrigeration or a passive evaporative system, both exhausting to the surface through an armored flexible fluidic communication mechanical cable.

Lamers, M.D.; Martelli, V.P.

1981-02-03

375

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.

376

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 E9701', N4513' , 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

377

75 FR 61698 - Federal Consistency Appeal by Pan American Grain Co.  

Federal Register 2010, 2011, 2012, 2013

...Atmospheric Administration Federal Consistency Appeal by Pan American Grain Co. AGENCY: National Oceanic and Atmospheric...filed with the Secretary of Commerce (Secretary) by Pan American Grain Co. (Pan American) has closed. No additional...

2010-10-06

378

75 FR 47262 - Federal Consistency Appeal by Pan American Grain Co.  

Federal Register 2010, 2011, 2012, 2013

...Atmospheric Administration Federal Consistency Appeal by Pan American Grain Co. AGENCY: National Oceanic and Atmospheric...decision record in an administrative appeal filed by Pan American Grain Co. (Pan American). DATES: The decision record for the...

2010-08-05

379

Apparatus and method for evaporator defrosting  

DOEpatents

An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator. The apparatus is alternately embodied with a first refrigerant bypass and/or a second refrigerant bypass for selectively directing refrigerant to respectively bypass the first refrigerant expansion device and the second refrigerant expansion device, and with the defrosting control connected to the first refrigerant bypass and/or the second refrigerant bypass to selectively activate and deactivate the bypasses depending upon the current cycle of the refrigeration system. The apparatus alternately includes an accumulator for accumulating liquid and/or gaseous refrigerant that is then pumped either to a refrigerant receiver or the first refrigerant expansion device for enhanced evaporator defrosting capability. The inventive method of defrosting an evaporator in a refrigeration system includes the steps of compressing refrigerant in a compressor and cooling the refrigerant in the condenser such that the refrigerant is substantially in liquid form, passing the refrigerant substantially in liquid form through the evaporator, and expanding the refrigerant with a refrigerant expansion device after the refrigerant substantially passes through the evaporator.

Mei, Viung C. (Oak Ridge, TN); Chen, Fang C. (Knoxville, TN); Domitrovic, Ronald E. (Knoxville, TN)

2001-01-01

380

Molecular cloning and characterization of crustacean type-one dopamine receptors: D1?Pan and D1?Pan  

PubMed Central

Dopamine (DA) differentially modulates identified neurons in the crustacean stomatogastric nervous system (STNS). While the electrophysiological actions of DA have been well characterized, little is known about the dopaminergic transduction cascades operating in this system. As a first step toward illuminating the molecular underpinnings of dopaminergic signal transduction in the crustacean STNS, we have cloned and characterized two type-one DA receptors (DARs) from the spiny lobster (Panulirus interruptus): D1?Pan and D1?Pan. We found that the structure and function of these arthropod DARs are well conserved across species. Using a heterologous expression system, we determined that DA, but not serotonin, octopamine, tyramine or histamine activates these receptors. When stably expressed in HEK cells, the D1?Pan receptor couples with Gs, and DA elicits an increase in [cAMP]. The D1?Pan receptor responds to DA with a net increase in [cAMP] that is mediated by Gs and Gz.

Clark, Merry C.; Baro, Deborah J.

2014-01-01

381

Effect of relative humidity on contact angle of inkjet-printed evaporating colloidal drops  

NASA Astrophysics Data System (ADS)

The deposition behavior of inkjet-printed aqueous colloidal drops onto glass and polymer (PEN and PET) substrates has been investigated by using fluorescence microscopy, a high-resolution CCD camera, and scanning electron microscopy. Real-time side-view images show that the contact angle of an evaporating colloidal drop is a function of the ambient humidity. The relative humidity also affects the extent to which the drop is able to spread after impacting a substrate, the evaporation rate at the drop surface, and the evaporatively-driven flow inside the drop that drives the suspended particles towards the contact line. The difference between the contact line velocity and liquid velocity at the drop contact line induced by evaporation creates a larger contact angle compared to that of the case without evaporation. This increase in contact angle becomes more significant for a low ambient humidity. Results also show that the particle deposition area and pattern change with the ambient humidity.

Chhasatia, Viral; Joshi, Abhijit; Sun, Ying

2010-11-01

382

Dynamics of water evaporation fronts  

NASA Astrophysics Data System (ADS)

The evolution and shapes of water evaporation fronts caused by long-wave instability of vertical flows with a phase transition in extended two-dimensional horizontal porous domains are analyzed numerically. The plane surface of the phase transition loses stability when the wave number becomes infinite or zero. In the latter case, the transition to instability is accompanied with reversible bifurcations in a subcritical neighborhood of the instability threshold and by the formation of secondary (not necessarily horizontal homogeneous) flows. An example of motion in a porous medium is considered concerning the instability of a water layer lying above a mixture of air and vapor filling a porous layer under isothermal conditions in the presence of capillary forces acting on the phase transition interface.

Il'ichev, A. T.; Shargatov, V. A.

2013-09-01

383

Heat Transfer in the Evaporators of a Double-Evaporator Refrigerating System  

Microsoft Academic Search

This paper presents the heat transfer characteristics of the evaporators in a double-evaporator refrigerating system with an environment-friendly refrigerant, propane (R-290). Based on the Buckingham Pi theorem, dimensionless correlations are developed to predict the heat transfer coefficients of the refrigerant in high- and low-temperature evaporators (hH and hL) and the ratio of the cooling capacity of the high-temperature evaporator to

Chao-Jen Li; Jiung-Horng Lin; Chin-Chia Su

2006-01-01

384

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

NASA Technical Reports Server (NTRS)

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 10 to the -8th g per sq cm/sec, a flowing channel of liquid water will be covered by ice which evaporates sufficiently slowly that the water below can flow for hundreds of kilometers even with modest discharges. Evaporation rates are calculated for a range of frictional velocities, atmospheric pressures, and insolations and it is suggested that some subset of observed Martian channels may have formed as ice-choked rivers. Finally, the exobiological implications of ice covered channels or lakes on Mars are discussed.

Wallace, D.; Sagan, C.

1979-01-01

385

Evaporation from Arctic sea ice in summer during the International Geophysical Year, 1957-1958  

NASA Astrophysics Data System (ADS)

Measurements of pan evaporation were made during the summers of 1957 and 1958 on an ice station drifting between 80 and 86N. Using weather reports, measurements were either screened for absence of precipitation (to obtain evaporation, E) or not screened (to obtain P-E). Applying the screened data either to the entire month or only to the days without precipitation results in upper and lower limits to E. Monthly average values of E are positive in June and July, 3-5 and 5-8 mm/month, within the range of prior estimates, but are negative in August and September, indicating net deposition of frost or dew, at variance with prior estimates. The monthly averages of latent heat flux are small, 2-10 W m-2, by comparison to the individual components of net radiation, each on the order of 100-300 W m-2.

Froyland, Hugo K.; Untersteiner, Norbert; Town, Michael S.; Warren, Stephen G.

2010-08-01

386

Precursor Lesions for Sporadic Pancreatic Cancer: PanIN, IPMN, and MCN  

PubMed Central

Pancreatic cancer is still a dismal disease. The high mortality rate is mainly caused by the lack of highly sensitive and specific diagnostic tools, and most of the patients are diagnosed in an advanced and incurable stage. Knowledge about precursor lesions for pancreatic cancer has grown significantly over the last decade, and nowadays we know that mainly three lesions (PanIN, and IPMN, MCN) are responsible for the development of pancreatic cancer. The early detection of these lesions is still challenging but provides the chance to cure patients before they might get an invasive pancreatic carcinoma. This paper focuses on PanIN, IPMN, and MCN lesions and reviews the current level of knowledge and clinical measures.

Distler, M.; Aust, D.; Weitz, J.; Pilarsky, C.; Grutzmann, Robert

2014-01-01

387

Pan-Nitinol Occluder and Special Delivery Device for Closure of Patent Ductus Arteriosus  

PubMed Central

The aim of this study was to evaluate a new type of occluder for patent ductus arteriosus. Patent ductus arteriosus was established in a canine model by anastomosing a length of autologous jugular vein to the descending aorta and the left pulmonary artery in an end-to-side fashion. Transcatheter closure of each patent ductus arteriosus was performed on 10 dogs, which were then monitored for as long as 6 months with aortography, echocardiography, and histologic evaluation. Transcatheter closure with use of the novel pan-nitinol device was successful in all canine models. Postoperative echocardiography showed that the location and shape of the occluders were normal, without any residual shunting. Further histologic evaluation confirmed that the occluder surface was completely endothelialized 3 months after implantation. Transcatheter patent ductus arteriosus closure with the pan-nitinol occluder can be performed safely and successfully in a canine model and shows good biological compatibility and low mortality rates.

Jiang, Hai-bin; Bai, Yuan; Zong, Gang-jun; Han, Lin; Li, Wei-ping; Lu, Yang; Qin, Yong-wen; Zhao, Xian-xian

2013-01-01

388

Thermo-evaporative fluxes from heterogeneous porous surfaces resolved by infrared thermography  

NASA Astrophysics Data System (ADS)

Variations in evaporative fluxes from heterogeneous wet terrestrial surfaces may induce a distinct and spatially variable thermal signature detectable by modern infrared thermography (IRT) methods. Combining measured temperature distribution for an evaporative surface with surface energy balance offers a means for extraction of spatial and temporal distributions of evaporative flux as a function of surface temperature. Recent advances in IRT technology offer spatially resolved thermal images at unprecedented sensitivity for in situ estimation of surface evaporation flux distribution currently unobservable by other methods. We studied evaporation patterns from surfaces of initially saturated sand columns containing sharp vertical textural contrasts (fine-sand inclusion in coarse-sand background) to evaluate the performance of the proposed method. We examined several algorithms for model validation. Spatial and temporal IRT data are numerically inverted to obtain evaporation flux values that are compared with rates of mass loss from direct weighing of the samples. Analytical solutions of some special cases are also compared with the experimental data. We introduce a convenient approximation based on mean surface temperatures of similar textural regions to resolve spatial evaporative fluxes. Estimates are in good agreement with experimental results. Our results also confirm the occurrence of lateral capillary flows from coarse to fine sand in the presence of sharp heterogeneity during evaporation. The proposed method could under certain conditions be used to convert highly resolved temperature fields to deduce drying patterns of interest in various fields from hydrology to food processing and other engineering applications.

Shahraeeni, Ebrahim; Or, Dani

2010-09-01

389

Growth Mechanism of Zinc Oxide Nanostructures by Carbothermal Evaporation Technique  

Microsoft Academic Search

Zn\\/ZnO nanostructures such as nanowires and nanotetrapods have been prepared by carbothermal evaporation under flowing argon and oxygen gases. Morphology of ZnO structures has been controlled by changing the time\\/temperature of the inlet and flow rate of the oxygen gas. Mechanism for the growth of nanowires and tetrapods has been discussed. It is seen that the nanostructure of prepared material

Aditee Joshi; S. K. Gupta; Manmeet Kaur; J. B. Singh; J. V. Yakhmi

2009-01-01

390

A method for evaporating silicon to form low dimensional Si lattice structures  

NASA Astrophysics Data System (ADS)

Physical deposition by evaporation is a convenient and cost effective method for generating thin layers of material. In this work, we utilise an electron-beam evaporation system retrofitted with a rotating shutter to control and reduce the deposition rate of materials. Under normal conditions, the evaporator is able to achieve a typical deposition rate of 1 A/s. In order to reduce the deposition rate, a rotating shutter was designed and retrofitted to the evaporator. The rotating shutter consists of a metal plate with a slit opening of 6 and 36. When rotated during evaporation, a reduction in deposition rate of 1/60 and 1/10 onto a sample is expected. We can control the deposition to achieve a rate of 1 A/min. By using this modified system, we deposited Si and SiO2 onto Si substrates. In situ deposition is monitored using a quartz thickness monitor. After evaporation, film thickness is measured using AFM and verified with spectroscopic ellipsometer measurement. Using this method, we are able to reach a deposited film thickness of 3 nm. This work is expected to contribute significantly towards the fabrication of low dimensional silicon devices.

Ng, David C.; Ganesan, Kumar; Stacey, Alastair; Skafidas, Efstratios

2013-12-01

391

Hollow Fiber Ground Evaporator Unit Testing  

NASA Technical Reports Server (NTRS)

A candidate technology for 1-atmosphere suited heat rejection was developed and tested at NASA Johnson Space Center. The concept is to use a collection of microporous hydrophobic tubes potted between inlet and outlet headers with water as coolant. A pump provides flow between headers through the tubes which are subjected to fan driven cross flow of relatively dry air. The forced ventilation would sweep out the water vapor from the evaporation of the coolant rejecting heat from the coolant stream. The hollow fibers are obtained commercially (X50-215 Celgard) which are arranged in a sheet containing 5 fibers per linear inch. Two engineering development units were produced that vary the fold direction of the fiber sheets relative to the ventilation. These units were tested at inlet water temperatures ranging from 20 deg C to 30 deg C, coolant flow rates ranging from 10 to 90 kg/hr, and at three fan speeds. These results were used to size a system that could reject heat at a rate of 340 W.

Bue, Grant; Trevino, Luis; Tsioulos, Gus

2010-01-01

392

Evaporated Silicon Thin-Film Transistors.  

National Technical Information Service (NTIS)

The method of fabrication, the theory and properties of evaporated silicon thin-film transistors are discussed. The device consists of a p-type silicon film (0.5-2 microns thick) on a sapphire substrate, with aluminum source-drain electrodes evaporated on...

C. A. T. Salama L. Young

1966-01-01

393

Evaporated Silicon Thin-Film Transistors.  

National Technical Information Service (NTIS)

Preliminary results on thin-film transistors having evaporated silicon films on sapphire are described. The silicon is evaporated first onto the sapphire substrate and is followed by the aluminum source-drain electrodes. The silicon oxide SiOx insulator i...

C. A. T. Salama L. Young

1965-01-01

394

Practical application of an evaporation duct model  

Microsoft Academic Search

The application of an evaporation duct model in operational and climatological assessments of propagation and the sensitivity of the model to meteorological measurements are examined. The unexpectedly frequent occurrence of evaporation duct heights greater than 40 m is related to thermally stable conditions in the atmospheric surface layer. The existence of stable conditions over the ocean is analyzed in terms

R. A. Paulus

1985-01-01

395

Evaporation from porous surfaces into turbulent air flows-On the coupling of momentum and thermal signatures  

NASA Astrophysics Data System (ADS)

The ubiquitous and energy intensive mass transfer between evaporating surfaces and convective air streams is of great interest for various natural and industrial applications. Turbulent air flows above surfaces are common and are associated with complex and highly dynamic boundary conditions that must be considered for prediction of surface evaporation rates. During a certain period in the drying process where phase change takes place primarily at the surface (the so called stage-1 evaporation), one may use thermal signatures associated with the complex evaporation filed using infrared thermography (IRT) to characterize instantaneous evaporation rates. The study explores quantifiable links between the spatio-temporal distribution of eddy-induced localized evaporation rates and associated thermal signatures to deduce overall evaporative losses and to quantify characteristics of turbulent airflow. Preliminary results suggest that the methodology offers unique opportunities for directly linking turbulent eddies interacting with the surface and the resulting evaporative fluxes thereby providing the essential building blocks for upscaling results to field and landscape scales for a range of turbulent flow regimes. Keywords: Evaporative Drying, Turbulence, Surface Renewal, Infrared Thermography.

Haghighi, Erfan; Or, Dani

2013-04-01

396

Contribution of impervious surfaces to urban evaporation  

NASA Astrophysics Data System (ADS)

data and the Princeton urban canopy model, with its detailed representation of urban heterogeneity and hydrological processes, are combined to study evaporation and turbulent water vapor transport over urban areas. The analyses focus on periods before and after precipitation events, at two sites in the Northeastern United States. Our results indicate that while evaporation from concrete pavements, building rooftops, and asphalt surfaces is discontinuous and intermittent, overall these surfaces accounted for nearly 18% of total latent heat fluxes (LE) during a relatively wet 10 day period. More importantly, these evaporative fluxes have a significant impact on the urban surface energy balance, particularly during the 48 h following a rain event when impervious evaporation is the highest. Thus, their accurate representation in urban models is critical. Impervious evaporation after rainfall is also shown to correlate the sources of heat and water at the earth surface, resulting in a conditional scalar transport similarity over urban terrain following rain events.

Ramamurthy, P.; Bou-Zeid, E.

2014-04-01

397

The ATLAS PanDA Monitoring System and its Evolution  

NASA Astrophysics Data System (ADS)

The PanDA (Production and Distributed Analysis) Workload Management System is used for ATLAS distributed production and analysis worldwide. The needs of ATLAS global computing imposed challenging requirements on the design of PanDA in areas such as scalability, robustness, automation, diagnostics, and usability for both production shifters and analysis users. Through a system-wide job database, the PanDA monitor provides a comprehensive and coherent view of the system and job execution, from high level summaries to detailed drill-down job diagnostics. It is (like the rest of PanDA) an Apache-based Python application backed by Oracle. The presentation layer is HTML code generated on the fly in the Python application which is also responsible for managing database queries. However, this approach is lacking in user interface flexibility, simplicity of communication with external systems, and ease of maintenance. A decision was therefore made to migrate the PanDA monitor server to Django Web Application Framework and apply JSON/AJAX technology in the browser front end. This allows us to greatly reduce the amount of application code, separate data preparation from presentation, leverage open source for tools such as authentication and authorization mechanisms, and provide a richer and more dynamic user experience. We describe our approach, design and initial experience with the migration process.

Klimentov, A.; Nevski, P.; Potekhin, M.; Wenaus, T.

2011-12-01

398

The Pan-STARRS1 Small Area Survey 2  

NASA Astrophysics Data System (ADS)

The Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) survey is acquiring multi-epoch imaging in five bands (gP1, rP1, iP1, zP1, yP1) over the entire sky north of declination -30 (the 3? survey). In 2011 July a test area of about 70 deg2 was observed to the expected final depth of the main survey. In this, the first of a series of papers targeting the galaxy count and clustering properties of the combined multi-epoch test area data, we present a detailed investigation into the depth of the survey and the reliability of the Pan-STARRS1 analysis software. We show that the Pan-STARRS1 reduction software can recover the properties of fake sources, and show good agreement between the magnitudes measured by Pan-STARRS1 and those from Sloan Digital Sky Survey. We also examine the number of false detections apparent in the Pan-STARRS1 data. Our comparisons show that the test area survey is somewhat deeper than the Sloan Digital Sky Survey in all bands, and, in particular, the z band approaches the depth of the stacked Sloan Stripe 82 data.

Metcalfe, N.; Farrow, D. J.; Cole, S.; Draper, P. W.; Norberg, P.; Burgett, W. S.; Chambers, K. C.; Denneau, L.; Flewelling, H.; Kaiser, N.; Kudritzki, R.; Magnier, E. A.; Morgan, J. S.; Price, P. A.; Sweeney, W.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

2013-11-01

399

Detecting diminutive colorectal lesions at colonoscopy: a randomised controlled trial of pan-colonic versus targeted chromoscopy  

PubMed Central

Background: Diminutive and flat colorectal lesions can be difficult to detect using conventional colonoscopic techniques. Previous data have suggested that pan-chromoscopy may improve detection rates. No randomised control trial has been performed examining detection rates of such lesions while controlling for extubation time and lavage effect. Aim: We conducted a randomised controlled trial of pan-colonic chromoscopic colonoscopy for the detection of diminutive and flat colorectal lesions while controlling for extubation time and lavage effect. Methods: Consecutive patients attending for routine colonoscopy were randomised to either pan-chromoscopy using 0.5% indigo carmine (IC) or targeted chromoscopy (control group). A minimum diagnostic extubation time was set at eight minutes with controls undergoing a matched volume of saline wash. Results: A total of 260 patients were randomised; 132 controls and 128 to pan-colonic chromoscopy. Extubation times did not differ significantly between the control (median 15 minutes (range 841)) and chromoscopy (median 17 minutes (range 839)) groups. The volume of IC used in the pan-chromoscopy group (median 68 ml (range 6590)) and normal saline used in the control group (69 ml (range 6093)) did not differ significantly. There was a statistically significant difference between the groups regarding the total number of adenomas detected (p<0.05) with significantly more diminutive (<4 mm) adenomas detected in the pan-chromoscopy group (p?=?0.03). Pan-chromoscopy diagnosed more diminutive and flat lesions in the right colon compared with controls (p<0.05), with more patients with multiple adenomas (>3) detected using pan-chromoscopy (p<0.01). Hyperplastic lesions were more commonly detected in the pan-chromoscopy group compared with controls (p<0.001). More hyperplastic polyps were detected in the left colon (86% rectosigmoid) using chromoscopy compared with controls. Conclusion: Chromoscopy improves the total number of adenomas detected and enhances the detection of diminutive and flat lesions. Importantly, eight diminutive lesions had foci of high grade dysplasia. Chromoscopy may benefit patients, assuming a high risk of colorectal cancer, and help in risk stratification and planning follow up colonoscopy intervals.

Hurlstone, D P; Cross, S S; Slater, R; Sanders, D S; Brown, S

2004-01-01

400

Possible roles of consolation in captive chimpanzees (Pan troglodytes).  

PubMed

Empathy is a necessary prerequisite for the occurrence of consolation. The term "consolation" contains a hypothesis about function, which is distress alleviation. The present study aims to confirm the occurrence of consolation in captive chimpanzees via the post-conflict/matched-control method (PC-MC) and to suggest its possible roles. We collected 273 PC-MC pairs in the group of Pan troglodytes housed in the ZooParc de Beauval (France). We confirmed the presence of consolatory contacts (mean level of consolation, 49.5% +/- 22.3% SEM) in the colony. Consolation rates were significantly higher than reconciliation levels (mean level of reconciliation, 28.9% +/- 16.8% SEM). The level of consolation was greater in the absence of reconciliation than in the presence of it, suggesting that consolation might be an alternative behavior. As friendship and relatedness did not influence the occurrence of consolation, they did not seem to be the best prerequisites for this behavioral mechanism, at least in this chimpanzee colony. Affinitive contacts with third parties were significantly more frequent when the victim called attention to itself during severe aggressions by screaming. These high-pitched sounds seem to be useful in eliciting aid from conspecifics, as occurs in young humans. The occurrence of consolation reduced the likelihood of further attacks among group-members. From this perspective, both victims and consolers most likely gain potential advantages by interacting with each other when aggression is particularly severe, reconciliation is not immediate, and consequently social stress reaches high levels. PMID:16229027

Palagi, Elisabetta; Cordoni, Giada; Borgognini Tarli, Silvana

2006-01-01

401

Apparent evaporative resistance at critical conditions for five clothing ensembles.  

PubMed

A limiting factor for clothing ensembles inherent during heat stress exposures is the evaporative resistance, which can be used to compare candidate ensembles and in rational models of heat exchange. In this study, the apparent total evaporative resistance of five clothing ensembles (cotton work clothes, cotton coveralls, and coveralls made of Tyvek 1424 and 1427, NexGen and Tychem QC was estimated empirically from wear trials using a progressive heat stress protocol and from clothing insulation adjustments based on ISO 9920 (2007) and wetness. The metabolic rate was moderate at 165 W m(-2) and relative humidity was held at 50%. Twenty-nine heat-acclimated participants (20 men and 9 women) completed trials for all clothing ensembles. A general linear mixed effects model (ensemble and participants as a random effect) was used to analyze the data. Significant differences (p < 0.0001) among ensembles were observed for apparent total evaporative resistance. As expected, Tychem QC had the highest apparent total evaporative resistance at 0.033 kPa m(2) W(-1). NexGen was next at 0.017 kPa m(2) W(-1). These were followed by Tyvek 1424 at 0.015 kPa m(2) W(-1), and Tyvek 1427, Cotton Coveralls and Work Clothes all at 0.013 kPa m(2) W(-1). This wear test method improves on past methods using the progressive protocol to determine evaporative resistance by including the effects of movement, air motion and wetness on the estimate of clothing insulation. The pattern of evaporative resistance is the same as that for critical WBGTs and a linear relationship between apparent total evaporative resistance and WBGT clothing adjustment factor is suggested. With the large sample size, a good estimate of sample variance associated with progressive method can be made, where the standard error is 0.0044 kPa m(2) W(-1) with a 95% confidence interval of 0.0040-0.0050 kPa m(2) W(-1). PMID:18172671

Caravello, Victor; McCullough, Elizabeth A; Ashley, Candi D; Bernard, Thomas E

2008-09-01

402

Cardiovascular studies using the chimpanzee (Pan troglodytes)  

NASA Technical Reports Server (NTRS)

Despite the phylogenetic similarities between chimpanzees and man, there exists a paucity of reliable data on normal cardiovascular function and the physiological responses of the system to standard interventions. Totally implanted biotelemetry systems or hardwire analog techniques were used to examine the maximum number of cardiovascular variables which could be simultaneously monitored without significantly altering the system's performance. This was performed in order to acquire base-line data not previously obtained in this species, to determine cardiovascular response to specific forcing functions such as ventricular pacing, drug infusions, and lower body negative pressure. A cardiovascular function profile protocol was developed in order to adjust independently the three major factors which modify ventricular performance, namely, left ventricular performance, left ventricular preload, afterload, and contractility. Cardiac pacing at three levels above the ambient rate was used to adjust end diastolic volume (preload). Three concentrations of angiotensin were infused continuously to evaluate afterload in a stepwide fashion. A continuous infusion of dobutamine was administered to raise the manifest contractile state of the heart.

Hinds, J. E.; Cothran, L. N.; Hawthorne, E. W.

1977-01-01

403

Enhanced evaporation from surfaces of width comparable to that of the mass boundary layer thickness  

NASA Astrophysics Data System (ADS)

We investigate the optimal distribution of spacing and size of stomata on a leaf, which enhances net evaporation rate. Although evaporation flux is known to be maximal at contact lines, is diffusion of the vapor also enhanced by the accompanying increase in the total perimeter when the contact lines are adjacent? The evaporation rate from the stomata is analyzed using a 1-D model for stomata distributions on a leaf and a 2-D convection-diffusion equation in the surrounding space. A universal behavior is observed as a function of the Peclet number Pe and stomata size. For stomata much wider than the mass boundary layer thickness, evaporation rate increases as the stomata are made smaller; but below a critical size, the evaporation rate saturates to a constant value. This transition occurs when stomata size is comparable to the mass boundary layer thickness. We experimentally tested this behavior with liquid evaporating from micro-channels of varying channel widths in a wind tunnel providing a range of Pe.

Ip, Karine; Mandre, Shreyas

2011-11-01

404

Structural Oil Pan With Integrated Oil Filtration And Cooling System  

DOEpatents

An oil pan for an internal combustion engine includes a body defining a reservoir for collecting engine coolant. The reservoir has a bottom and side walls extending upwardly from the bottom to present a flanged lip through which the oil pan may be mounted to the engine. An oil cooler assembly is housed within the body of the oil pan for cooling lubricant received from the engine. The body includes an oil inlet passage formed integrally therewith for receiving lubricant from the engine and delivering lubricant to the oil cooler. In addition, the body also includes an oil pick up passage formed integrally therewith for providing fluid communication between the reservoir and the engine through the flanged lip.

Freese, V, Charles Edwin (Westland, MI)

2000-05-09

405

Thermal mapping of salt pans at the Dead Sea works  

NASA Astrophysics Data System (ADS)

Water of the Dead Sea is unique in its chemical composition, having a very high concentration of alkaline salts, mainly Na, K, Mg and Br. The very hot and arid climate of the Dead Sea region enables separation of the different salts of the solvent in shallow open pans. A project, financed by the Israeli ``Dead Sea Works'' potash plant has used multitemporal thermal mapping from LANDSAT TM images to monitor the process. Analysis has shown phenomena such as improper mixing of the solution in some pans and springs of brackish water, in others, which act as inhibitors to the proper settling of salts from the solution. Furthermore, apparent setting of potash early in the process in pans intended for NaCl deposition only, has also been shown.

Tal, A.; Issahary, D.

1992-07-01

406

Vacuum Evaporation of High Melting-Temperature Metal, Ti, by Handmade Electron Bombardment System  

NASA Astrophysics Data System (ADS)

A handmade electron bombardment system has been constructed to evaporate titanium metal with high melting temperature. The system is simply constructed from a spiral tungsten wire, a target of Ti rod and handmade power supply. Details of the electric power to melt the Ti rod target, the deposition rate on a substrate and the angular distribution of the evaporation direction are specified. Especially the shape of the head of the melted Ti rod is found to be very important to evaporate Ti atoms on a substrate effectively and uniformly.

Horio, Yoshimi; Hara, Yuichiro; Yamamoto, Yoshitaka; Morimoto, Hiroki

407

Mergers, cooling flows, and evaporation  

NASA Technical Reports Server (NTRS)

Mergers (the capture of cold gas, especially) can have a profound influence on the hot coronal gas of early-type galaxies and clusters, potentially inducing symptoms hitherto attributed to a cooling flow, if thermal conduction is operative in the coronal plasma. Heat can be conducted from the hot phase into the cold phase, simultaneously ionizing the cold gas to make optical filaments, while locally cooling the coronal gas to mimic a cooling-flow. If there is heat conduction, though, there is no standard cooling-flow since radiative losses are balanced by conduction and not mass deposition. Amongst the strongest observational support for the existence of cooling-flows is the presence of intermediate temperature gas with x-ray emission-line strengths in agreement with cooling-flow models. Here, x-ray line strengths are calculated for this alternative model, in which mergers are responsible for the observed optical and x-ray properties. Since gas around 10(exp 4) K is thermally stable, the cold cloud need not necessarily evaporate and hydrostatic solutions exist. Good agreement with the x-ray data is obtained. The relative strengths of intermediate temperature x-ray emission lines are in significantly better agreement with a simple conduction model than with published cooling-flow models. The good agreement of the conduction model with optical, infrared and x-ray data indicates that significantly more theoretical effort into this type of solution would be profitable.

Sparks, W. B.

1993-01-01

408

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

409

Evaporative losses from soils covered by physical and different types of biological soil crusts  

USGS Publications Warehouse

Evaporation of soil moisture is one of the most important processes affecting water availability in semiarid ecosystems. Biological soil crusts, which are widely distributed ground cover in these ecosystems, play a recognized role on water processes. Where they roughen surfaces, water residence time and thus infiltration can be greatly enhanced, whereas their ability to clog soil pores or cap the soil surface when wetted can greatly decrease infiltration rate, thus affecting evaporative losses. In this work, we compared evaporation in soils covered by physical crusts, biological crusts in different developmental stages and in the soils underlying the different biological crust types. Our results show that during the time of the highest evaporation (Day 1), there was no difference among any of the crust types or the soils underlying them. On Day 2, when soil moisture was moderately low (11%), evaporation was slightly higher in well-developed biological soil crusts than in physical or poorly developed biological soil crusts. However, crust removal did not cause significant changes in evaporation compared with the respective soil crust type. These results suggest that the small differences we observed in evaporation among crust types could be caused by differences in the properties of the soil underneath the biological crusts. At low soil moisture (<6%), there was no difference in evaporation among crust types or the underlying soils. Water loss for the complete evaporative cycle (from saturation to dry soil) was similar in both crusted and scraped soils. Therefore, we conclude that for the specific crust and soil types tested, the presence or the type of biological soil crust did not greatly modify evaporation with respect to physical crusts or scraped soils.

Chamizo, S.; Cantn, Y.; Domingo, F.; Belnap, J.

2013-01-01

410

Evaluation of polyacrylonitrile (PAN) as a binding polymer for absorbers used to treat liquid radioactive wastes.  

National Technical Information Service (NTIS)

The chemical and radiation stability of polyacrylonitrile (PAN) in the form of beads (B-PAN), similar to the beads of composite absorbers, and one selected composite absorber (ammonium molybdophosphate, the active component in PAN binder (AMP-PAN), a pros...

F. Sebesta J. John A. Motl K. Stamberg

1995-01-01

411

LABORATORY STUDIES OF THE DEPOSITION OF ALKALI SULFATE VAPORS FROM COMBUSTION GASES USING A FLASH-EVAPORATION TECHNIQUE  

Microsoft Academic Search

A relatively simple experimental technique is proposed and demonstrated for making measurements of absolute dewpoints and relative deposition rates from flowing combustion gases containing condensible inorganic vapors (here alkali sulfates). In using this flash evaporation technique, one first accumulates an inventory of condensate on a Pt-ribbon target maintained below the dewpoint and then flash-evaporates this condensate inventory into the filament

DANIEL. E. ROSNER; BAISHEN LIANG

1986-01-01

412

Measurement of an Evaporating Drop on a Reflective Substrate  

NASA Technical Reports Server (NTRS)

A figure depicts an apparatus that simultaneously records magnified ordinary top-view video images and laser shadowgraph video images of a sessile drop on a flat, horizontal substrate that can be opaque or translucent and is at least partially specularly reflective. The diameter, contact angle, and rate of evaporation of the drop as functions of time can be calculated from the apparent diameters of the drop in sequences of the images acquired at known time intervals, and the shadowgrams that contain flow patterns indicative of thermocapillary convection (if any) within the drop. These time-dependent parameters and flow patterns are important for understanding the physical processes involved in the spreading and evaporation of drops. The apparatus includes a source of white light and a laser (both omitted from the figure), which are used to form the ordinary image and the shadowgram, respectively. Charge-coupled-device (CCD) camera 1 (with zoom) acquires the ordinary video images, while CCD camera 2 acquires the shadowgrams. With respect to the portion of laser light specularly reflected from the substrate, the drop acts as a plano-convex lens, focusing the laser beam to a shadowgram on the projection screen in front of CCD camera 2. The equations for calculating the diameter, contact angle, and rate of evaporation of the drop are readily derived on the basis of Snell s law of refraction and the geometry of the optics.

Chao, David F.; Zhang, Nengli

2004-01-01

413

Determination of the Evaporation Coefficient of D2O  

SciTech Connect

The evaporation rate of D{sub 2}O has been determined by Raman thermometry of a droplet train (12-15 {micro}m diameter) injected into vacuum ({approx}10{sup -5} torr). The cooling rate measured as a function of time in vacuum was fit to a model that accounts for temperature gradients between the surface and the core of the droplets, yielding an evaporation coefficient ({gamma}{sub e}) of 0.57 {+-} 0.06. This is nearly identical to that found for H{sub 2}O (0.62 {+-} 0.09) using the same experimental method and model, and indicates the existence of a kinetic barrier to evaporation. The application of a recently developed transition state theory (TST) model suggests that the kinetic barrier is due to librational and hindered translational motions at the liquid surface, and that the lack of an isotope effect is due to competing energetic and entropic factors. The implications of these results for cloud and aerosol particles in the atmosphere are discussed.

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

2008-03-26

414

Synchrotron-radiation-stimulated evaporation and defect formation in a-SiO2  

Microsoft Academic Search

The vacuum ultraviolet-stimulated evaporation of a-SiO2 and formation of oxygen vacancy defects in a-SiO2 was found to be temperature dependent. Below a 500 C surface oxygen atoms are depleted, a SiOx layer is formed, and the a-SiO2 is etched at a constant rate by photon-stimulated desorption of constituent atoms. Between 500 and 700 C the a-SiO2 itself decomposes and evaporates

Housei Akazawa

1995-01-01

415

Evaporation of R134a in a horizontal herringbone microfin tube: heat transfer and pressure drop  

Microsoft Academic Search

An experimental investigation of in-tube evaporation of R134a has been carried out for a 4m long herringbone microfin tube with an outer diameter of 9.53mm. Measured local heat transfer coefficients and pressure losses are reported for evaporation temperatures between ?0.7 and 10.1C and mass flow rates between 162 and 366kgm?2s?1. Results from this work are compared to experimental results from

S. Wellsandt; L. Vamling

2005-01-01

416

Growth of shape controlled silicon nanowhiskers by electron beam evaporation  

NASA Astrophysics Data System (ADS)

We investigated the effect of the deposition rate on the surface morphology of Si nanowhiskers (NW) deposited by e-beam evaporation using the vapor-liquid-solid growth mechanism. The roles of deposition rate and corresponding surface diffusion on the Si NW growth kinetics were examined. Two growth regimes were observed within the investigated range of deposition rates. Films belonging to these two regimes were found to have characteristically different formations and surface morphologies. We found that the length-diameter curves of NWs switch from decreasing to increasing at a certain critical evaporation rate. The surface morphology is composed of long whiskers (~1 ?m) tapered with faceted sidewalls in the high deposition rate regimes (above 1.2 /s) due to their length which is comparable with the adatom diffusion and the direct adsorption of Si atoms on the sidewalls. The characteristic morphology was composed of shorter straight whiskers in the low deposition rate regimes (0.6-1 /s) because of the higher contribution of Si adatoms diffusing from the substrate to the NW growth.

Karakiz, Mehmet; Toydemir, Burcu; Unal, Bayram; Colakerol Arslan, Leyla

2014-02-01

417

Atmospheric dispersion of ammonia accidentally released from the 242-A Evaporator, Hanford Site, Richland, Washington  

SciTech Connect

Two errors have been identified in the authorization basis for the 242-A Evaporator at the Hanford Site. These errors, which appear in the 242-A Evaporator/Crystallizer Final Safety Analysis Report analysis of ammonia gas concentrations accidentally released from the 242-A Evaporator, are: (1) the vessel ventilation system flow rate used in the previous calculations is a factor of ten higher than the actual flow rate, and (2) the previous calculations did not account for the ammonia source term reduction that would occur via condensation of ammonia vapors, which will remove a large fraction of the ammonia from the exhaust gas stream. The purpose of this document is to correct these errors and recalculate the maximum ground-level concentrations of ammonia released to the environment as a result of potential errors in blending Evaporator feed. The errors offset each other somewhat, so it is unlikely that the 242-A Evaporator has operated outside its current authorization basis. However, the errors must be corrected and the results incorporated into a revision of the 242-A Evaporator/Crystallizer Safety Analysis Report, WHC-SD-WM-SAR-023. An EPA-approved atmospheric dispersion model, SCREEN3, was used to recalculate the maximum ground-level concentrations of ammonia that would be released from the 242-A Evaporator as a result of a feed-blending error. The results of the re-analysis of the 242-A Evaporator`s ammonia release scenario are as follows. The onsite receptor 100 m away from the release point (242-A vessel vent stack) is projected to be exposed to a maximum ground-level concentration of ammonia of 8.3 ppm. The maximally-exposed offsite receptor, located at the nearest Hanford Site boundary 16 km away from the 242-A vessel vent stack, will be exposed to a maximum ground-level concentration of 0.11 ppm ammonia.

Daling, P.M.; Lavender, J.C.

1997-11-01

418

Fundamental experiments on evaporation of cesium in ion sources.  

PubMed

Basic experiments are carried out to study the cesium evaporation