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1

Design and testing of a mini Class A evaporation pan  

Microsoft Academic Search

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 used to design a mini Class A pan at a scale that would create an

A. Vassar; L. Pochop; V. Hasfurther

1987-01-01

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

Modeling of Daily Pan Evaporation  

Microsoft Academic Search

Daily pan evaporation estimations are achieved by a suitable Artificial Neural Network (ANN) model for the meteorological data recorded from Automated GroWheather meteorological station near Lake Egirdir which lies in the Lake District of western Turkey. In this station six meteorological variables are measured simultaneously, namely, air temperature, water temperature, solar radiation, air pressure, wind speed and relative humidity. Since

Özlem Terzi; M. Erol Keskin

2005-01-01

4

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

Microsoft Academic Search

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

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

2009-01-01

5

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

6

On the attribution of changing pan evaporation  

Microsoft Academic Search

Evaporative demand, measured by pan evaporation, has declined in many regions over the last several decades. It is important to understand why. Here we use a generic physical model based on mass and energy balances to attribute pan evaporation changes to changes in radiation, temperature, humidity and wind speed. We tested the approach at 41 Australian sites for the period

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

2007-01-01

7

Pan Evaporation in the Southern Hemisphere: What is Happening ?  

Microsoft Academic Search

Pan evaporation has decreased throughout the northern hemisphere. The typical rate of decline is roughly 2 to 4 mm a-2, i.e., over the last 30 years the annual pan evaporation rate has decreased by between 60 to 120 mm a-1. However, whether this trend is restricted to the northern hemisphere, or whether it is a global trend is unknown because

M. L. Roderick; G. D. Farquhar

2004-01-01

8

Changes in New Zealand pan evaporation since the 1970s  

Microsoft Academic Search

Several previous studies have reported declines in pan evaporation rate throughout the Northern Hemisphere of about 2-4 mm a?2 for various periods since the 1950s. A recent analysis of Australian pan evaporation reported a similar decline and raises the possibility that part of the phenomenon may be related to the greenhouse effect. To assess that possibility, one needs to know

Michael L. Roderick; Graham D. Farquhar

2005-01-01

9

Mass Transfer Aspects of Pan Evaporation  

Microsoft Academic Search

Experimental evaporation data which were obtained with shallow, square pans of different sizes and colors, were studied by means of regression analysis relating evaporation with the difference between the water vapor pressure at the water surface and in the air, pan size, and wind speed at various elevations. These relationships are expressed by different equations for mass transfer whose functional

Wilfried Brutsaert; Shaw Lei Yu

1968-01-01

10

Detecting inhomogeneities in pan evaporation time series  

Microsoft Academic Search

There is increasingly growing demand for evaporation data for studies of surface water and energy fluxes, especially for studies which address the impacts of global warming. To serve this purpose, a homogeneous evaporation data are necessary. This paper describes the use of two tests for detecting and adjusting discontinuities in Class A pan evaporation time series for 28 stations across

D. G. C. Kirono

2009-01-01

11

PenPan: A general tool for the attribution of changing pan evaporation  

NASA Astrophysics Data System (ADS)

Evaporative demand is routinely measured using the evaporation of water from standardised pans. The most common are Class A pans: they are metal dishes 4 feet in diameter and 10 inches deep sitting on a wooden platform. Because of the practical importance in agriculture and engineering, there is a wealth of pan evaporation data. Analysis has shown that in most places, pan evaporation has declined over the last 30 to 50 years despite the well documented increases in near-surface air temperature. It is important to understand why this has occurred. Using generic principles of mass and energy balance, we developed the PenPan model of evaporation from a class A pan for attribution purposes. In this talk we briefly describe the PenPan model and then demonstrate its application at 41 sites, broadly scattered across Australia, for the period 1975-2004. We found that the decline in Australian pan evaporation was mostly due to declining wind speed with some regional contributions from declining radiation. In general, the observed changes in vapour pressure deficit and air temperature were too small to have an appreciable impact on pan evaporation rates. By a comparative analysis, we show that the general global trends of declining evaporative demand are most due to various combination of declining radiation and/or wind.

Farquhar, G. D.; Hobbins, M. T.; Roderick, M. L.; Rotstayn, L. D.

2007-12-01

12

Changing pan evaporation and its attribution in China  

NASA Astrophysics Data System (ADS)

Pan evaporation is an indicator of evaporation demand, which has declined in many regions over the past several decades. It is important to understand why and what dominant factors controlling pan evaporation are. We collected daily climate data from 122 meteorological stations across China for the past 50 years, including pan evaporation (with a diameter of 20cm), solar irradiance and etc. We approached pan evaporation using Penman equation, and quantified effect of climatic factors (namely radiation, temperature, humidity and wind speed) on pan evaporation using its partial derivations. We have a primary analysis according to the data from 9 stations, namely Harbin in Northeast, Aletai and Ruoqiang in Northwest, Germu and Changdu in Qinghai-Tibet Plateau, Taiyuan in North China, Chengdu in Southwest, Hangzhou in East China, and Guangzhou in South China. The result shows that pan evaporation has a downward trend (except Chengdu station), especially Aletai, Changdu and Guangzhou at a rate of over -10mm/yr2. Regarding the factors controlling pan evaporation change, declining wind speed is the major factor in 3 north stations (Harbin, Ruoqiang and Germu), at about -3~-5mm/yr2; change in vapor press deficit is most important in Aletai and Hangzhou, at about -3mm/yr2 and 3mm/yr2 respectively; decreasing solar irradiance is the key factor in Taiyuan, Changdu, Chengdu and Guangzhou, at about -4~-5mm/yr2. Generally, changing pan evaporation is controlled by weakening wind speed in the western part of China, and by declining solar irradiance in the eastern part. Further analysis on other stations will help to reveal regional variation in climatic drives of changing hydrologic cycle. In addition, comparing with the observed data, we found that decrease in net shortwave radiation was underestimated using empirical formula recommended in the Irrigation and Drainage Paper 56 by FAO. It is speculated that changing albedo and aerosols concentration have been altering regional energy balance.

Yang, H.; Yang, D.

2008-12-01

13

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

14

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

15

Changing pan evaporation and its attribution in China  

Microsoft Academic Search

Pan evaporation is an indicator of evaporation demand, which has declined in many regions over the past several decades. It is important to understand why and what dominant factors controlling pan evaporation are. We collected daily climate data from 122 meteorological stations across China for the past 50 years, including pan evaporation (with a diameter of 20cm), solar irradiance and

H. Yang; D. Yang

2008-01-01

16

Estimating Pan Evaporation from Limited Meteorological Observations from Turkey  

Microsoft Academic Search

Pan evaporation measurements are widely used to estimate evapotranspiration and free water evaporation. Pan evaporation measurements are critical to many applications including irrigation system design, irrigation scheduling, and hydrologic modeling. In many locations, reliable climate measurements consist of daily minimum screen temperature, daily maximum, rainfall, and windspeed. In many situations, it is advantageous to calculate rather than measure pan evaporation.

Fazli Ozturk; Halit Apaydin

1998-01-01

17

PenPan: A general tool for the attribution of changing pan evaporation  

Microsoft Academic Search

Evaporative demand is routinely measured using the evaporation of water from standardised pans. The most common are Class A pans: they are metal dishes 4 feet in diameter and 10 inches deep sitting on a wooden platform. Because of the practical importance in agriculture and engineering, there is a wealth of pan evaporation data. Analysis has shown that in most

G. D. Farquhar; M. T. Hobbins; M. L. Roderick; L. D. Rotstayn

2007-01-01

18

Study on Change Trend of Pan Evaporation in Recent Years of China  

NASA Astrophysics Data System (ADS)

Based on observational data of 664 meteorological stations in China from 1960 to 2000 and combined with the Geographic Information System of ArcGIS, the spatial and temporal distributions and their trends for pan evaporation in China are investigated. The results indicate that, from 1960 to 2000, the rate of pan evaporation has steadily decreased in China. Compared with the period of 1960s to 1970s, the rate of annual pan evaporation during 1980s to 1990s has decreased 99.8mm. Seasonal analysis show that the decrease of pan evaporation is mainly in spring, summer and winter. Spatial distribution of the rate of change shows that the decrease of pan evaporation is mainly occurred in East China and Central South China. Further analysis show that the decrease of pan evaporation is mainly related to reductions in solar irradiance resulting from sun-shine percentage decrease.

Zeng, Y.; Liu, C.; Qiu, X.

2007-12-01

19

Early Pan-African evolution of the basement around Elat, Israel, and the Sinai Peninsula revealed by single-zircon evaporation dating, and implications for crustal accretion rates  

SciTech Connect

The authors report {sup 207}Pb/{sup 206}Pb single-zircon evaporation ages for early Pan-African rocks from southern Israel and the northeastern Sinai Peninsula, the northernmost extension of the Arabian-Nubian shield. The oldest rocks are metamorphic schists of presumed island-arc derivation; detrital zircons date the source terrain at ca. 800-820 Ma. A major phase of tonalite-trondhjemite plutonism occurred at ca. 760-780 Ma; more evolved granitic rocks were emplaced at about 745 Ma. A metagabbro-metadiorite complex reflects the youngest igneous phase at ca. 640 Ma. We find no evidence for pre-Pan-African crust, and our data document important crust-forming events that correlate with similar episodes elsewhere in the shield. The widespread presence of early Pan-African juvenile rocks (i.e., ca. 760-850 Ma) in many parts of the Arabian-Nubian shield makes this period the most important in the magmatic history of the shield and supports earlier suggestions for unusually high crust-production rates.

Kroener, A. (Universitaet Mainz, Postfach (West Germany)); Eyal, M.; Eyal, Y. (Ben-Gurion Univ., Beer Sheva (Israel))

1990-06-01

20

Fortuitous Evaporation Pan Observations on the Alaskan North Slope  

Microsoft Academic Search

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

J. P. Mumm; D. L. Kane

2010-01-01

21

A critical overview of pan evaporation trends over the last 50 years  

Microsoft Academic Search

Despite the observed increases in global average temperature, observations across the world show that the rate of pan evaporation\\u000a at a regional scale has been steadily decreasing over the past 50 years. This is known as the pan evaporation paradox. This\\u000a paper reviews current reported pan evaporation trends, examines available theoretical explanations about this “paradox”, and\\u000a discusses current research gaps and

Guobin Fu; Stephen P. Charles; Jingjie Yu

2009-01-01

22

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

23

Moisture use by various plant species and its relation to pan evaporation and net radiation  

Microsoft Academic Search

Moisture use rates by 15 plant species representing cultivated crops, grasses, and legumes on a Greenville sandy loam were measured over the period from 1956 to 1962. Several irrigation regimes were used. Correlation of the data with open pan evaporation and net radiation measurements show that under conditions of ample moisture, either pan evaporation or net radiation may be used

B. D. Doss; O. L. Bennett; D. A. Ashley

1965-01-01

24

Study on Change Trend of Pan Evaporation in Recent Years of China  

Microsoft Academic Search

Based on observational data of 664 meteorological stations in China from 1960 to 2000 and combined with the Geographic Information System of ArcGIS, the spatial and temporal distributions and their trends for pan evaporation in China are investigated. The results indicate that, from 1960 to 2000, the rate of pan evaporation has steadily decreased in China. Compared with the period

Y. Zeng; C. Liu; X. Qiu

2007-01-01

25

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

26

Evolutionary neural networks for monthly pan evaporation modeling  

NASA Astrophysics Data System (ADS)

Evolutionary neural networks (ENN) is used for modeling pan evaporation.Data from two stations of Turkey are used in the study.ENN models are compared with fuzzy genetic, neuro-fuzzy and ANN methods.ENN models perform better than the other models.Pan evaporation can be successfully estimated by the ENN method.

Ki?i, Özgür

2013-08-01

27

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

Microsoft Academic Search

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

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

2009-01-01

28

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

29

A high-quality monthly pan evaporation dataset for Australia  

Microsoft Academic Search

A high-quality monthly pan evaporation dataset of 60 stations has been developed for monitoring long-term pan evaporation\\u000a trends over Australia. The quality control process involved examination of historical station metadata together with an objective\\u000a test comparing candidate series with neighboring stations. Identified points of discontinuity were located, including installations\\u000a of bird guards, site relocations and changes in exposure. Appropriate inhomogeneity

Branislava Jovanovic; David A. Jones; Dean Collins

2008-01-01

30

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

31

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

NASA Astrophysics Data System (ADS)

Theory relating changes in area-average evaporation with changes in the evaporation from pans or open water is developed. Such changes can arise by Type (a) processes related to large-scale changes in atmospheric concentrations and circulation that modify surface evaporation rates in the same direction, and Type (b) processes related to coupling between the surface and atmospheric boundary layer (ABL) at the landscape scale that usually modify area-average evaporation and pan evaporation in different directions. The interrelationship between evaporation rates in response to Type (a) changes is derived. They have the same sign and broadly similar magnitude but the change in area-average evaporation is modified by surface resistance. As an alternative to assuming the complementary evaporation hypothesis, the results of previous modeling studies that investigated surface-atmosphere coupling are parameterized and used to develop a theoretical description of Type (b) coupling via vapor pressure deficit (VPD) in the ABL. The interrelationship between appropriately normalized pan and area-average evaporation rates is shown to vary with temperature and wind speed but, on average, the Type (b) changes are approximately equal and opposite. Long-term Australian pan evaporation data are analyzed to demonstrate the simultaneous presence of Type (a) and (b) processes, and observations from three field sites in southwestern USA show support for the theory describing Type (b) coupling via VPD. England's victory over Australia in 2009 Ashes cricket test match series will not be mentioned.

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

2009-12-01

32

MODELUNG OF PAN EVAPORATION USING SUPPORT VECTOR MACHINES ALGORITHM  

Microsoft Academic Search

This paper present results of pan evaporation estimations using Support Vector Machines (SVMs) based approach for the meteorological data from Manasgaon climatic station near Anand Sagar Reservoir, Shegaon. At this station four meteorological variables are measured simultaneously, namely, air temperature, wind speed, sunshine hours and relative humidity. The SVMs architecture involves in using one output parameter (i.e. evaporation) and up

S. Deswal; Mahesh Pal

2008-01-01

33

From evaporating pans to transpiring plants (John Dalton Medal Lecture)  

NASA Astrophysics Data System (ADS)

The name of the original inventor of irrigated agriculture is lost to antiquity. Nevertheless, one can perhaps imagine an inquisitive desert inhabitant noting the greener vegetation along a watercourse and putting two and two together. Once water was being supplied and food was being produced it would be natural to ask a further question: how much water can we put on? No doubt much experience was gained down through the ages, but again, one can readily imagine someone inverting a rain gauge, filling it with water and measuring how fast the water evaporated. The inverted rain gauge measures the demand for water by the atmosphere. We call it the evaporative demand. I do not know if this is what actually happened but it sure makes an interesting start to a talk. Evaporation pans are basically inverted rain gauges. The rain gauge and evaporation pan measure the supply and demand respectively and these instruments are the workhorses of agricultural meteorology. Rain gauges are well known. Evaporation pans are lesser known but are in widespread use and are a key part of several national standardized meteorological networks. Many more pans are used for things like scheduling irrigation on farms or estimating evaporation from lakes. Analysis of the long records now available from standardized networks has revealed an interesting phenomenon, i.e., pan evaporation has increased in some places and decreased in other but when averaged over large numbers of pans there has been a steady decline. These independent reports from, for example, the US, Russia, China, India, Thailand, are replicated in the southern hemisphere in, for example, Australia, New Zealand and South Africa. One often hears the statement that because the earth is expected to warm with increasing greenhouse gas emissions then it follows that water will evaporate faster. The pan evaporation observations show that this widely held expectation is wrong. When expectations disagree with observations, it is the observations that win. That is the basis of science. In this Dalton Medal lecture we first examine pan evaporation observations and show why pan evaporation has declined. Armed with that knowledge we then investigate the consequences for plant water use and how this is directly coupled to the catchment water balance.

Roderick, Michael

2013-04-01

34

A simulation model for predicting hourly pan evaporation from meteorological data  

Microsoft Academic Search

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

J. M. Molina Martínez; V. Martínez Alvarez; M. M. González-Real; A. Baille

2006-01-01

35

Complementary relationship between daily evaporation in the environment and pan evaporation  

Microsoft Academic Search

Daily actual evaporation observed locally is compared to daily pan evaporation to clarify and test the validity of the complementary relationship at this timescale. For this purpose, use was made of actual evaporation measurements at two sites, namely, in the Konza Prairie, Kansas, during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment, and in the Little Washita

David M. Kahler; Wilfried Brutsaert

2006-01-01

36

A new two-Dimensional Physical Basis for the Complementary Relation Between Terrestrial and pan Evaporation  

NASA Astrophysics Data System (ADS)

Archived global measurements of water loss from evaporation pans constitute an important indirect measure of evaporative flux. Historical data from evaporation pans shows a decreasing trend over the last half century, but the relationship between pan evaporation and moisture-limited terrestrial evaporation is complex, leading to ambiguities in the interpretation of this data. Under energy-limited conditions, pan evaporation (Epan) and moisture-limited terrestrial evaporation (E) increase or decrease together, while in moisture- limited conditions these fluxes form a complementary relation in which increases in one rate accompany decreases in the other. This has lead to debate about the meaning of the observed trends in the context of changing climate. Here a two-dimensional numerical model of a wet pan in a drying landscape is used to demonstrate that, over a wide range of realistic atmospheric and surface conditions, the influence that changes in E have on Epan (1) are complementary and linear, (2) do not depend upon surface wind speed, and (3) are strikingly asymmetrical, in that a unit decrease in E causes approximately a five-fold increase in Epan, as found in a recent analysis of daily evaporation from US grasslands (Kahler and Brutsaert, 2006). Previous attempts to explain the CR have been based on one dimensional diffusion and energy balance arguments, leading to analytic solutions based on Penman-type bulk difference equations. But without acknowledging the spatially complex multidimensional humidity and temperature field around the pan, and specifically how these fields change as the contrast between the wet pan and the drying land surface increases, such integrated bulk difference equations are a priori incomplete (they ignore important divergence terms), and thus these explanations must be considered physically incomplete. Results of the present study improve the theoretical foundation of the CR, thus increasing the reliability with which it can be applied to estimate water balance and to understand the pan evaporation record of climate change.

Pettijohn, J. C.; Salvucci, G. D.

2008-12-01

37

Comparison of pan evaporation and actual evaporation estimated by land surface model in Xinjiang from 1960 to 2005  

Microsoft Academic Search

Pan evaporation, an indictor of potential evaporation, has decreased during the last several decades in many parts of the\\u000a world; the trend is contrary to the expectation that the increase of actual evaporation will accompany global warming, known\\u000a as the pan evaporation paradox. What is the essential relationship between pan evaporation and actual evaporation? This is\\u000a still an uncertain problem.

Bo Liu; Zhuguo Ma; Jingjing Xu; Ziniu Xiao

2009-01-01

38

A new two-Dimensional Physical Basis for the Complementary Relation Between Terrestrial and pan Evaporation  

Microsoft Academic Search

Archived global measurements of water loss from evaporation pans constitute an important indirect measure of evaporative flux. Historical data from evaporation pans shows a decreasing trend over the last half century, but the relationship between pan evaporation and moisture-limited terrestrial evaporation is complex, leading to ambiguities in the interpretation of this data. Under energy-limited conditions, pan evaporation (Epan) and moisture-limited

J. C. Pettijohn; G. D. Salvucci

2008-01-01

39

Solvent Evaporation Rates  

Microsoft Academic Search

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

DOUGLAS C. GRAY

1974-01-01

40

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

41

Trends in Thailand pan evaporation from 1970 to 2007  

NASA Astrophysics Data System (ADS)

One of the expected consequences of an anthropogenically warmed climate is the increase in evaporation. Paradoxically, terrestrial observations across the world show that the rates of pan evaporation (Epan) have been steadily decreasing since 1950s. In this study, we present a trend in Thailand Epan based on quality-controlled data from 28 weather stations from 1970 to 2007. Results indicated that, despite the annual mean air temperature increased by 0.91 °C over the past 38 years (0.024 °C per annum), the trend in annual Epan has steadily declined on average by ~ 7.7 mm a-2 (i.e. mm per annum per annum). By comparing, this change is larger than those previously reported for several countries. A further examination by Kendal's rank correlation and stepwise regression analysis based on some available weather data showed that reduction in wind speed and, to a lesser degree, sunshine duration were the likely causative meteorological factors affecting the Epan decrease in Thailand over the past 38 years. The findings of this study highlight local changes in aerodynamic and radiative drivers of the hydrological cycle, and their linkages to climate change could have important implications for Thailand's nature and society.

Limjirakan, Sangchan; Limsakul, Atsamon

2012-05-01

42

Changes in pan and visible evaporation over European Russia  

Microsoft Academic Search

Pan evaporation observations in the USSR began in the middle of 1950s. At the peak of the network extent (in the middle of 1980s) more than 150 stations performing these observations operated over European Russia. From 1990s the number of stations was significantly reduced, and at present data up to 2008 are available only for 25 stations, and up to

Nina Speranskaya

2010-01-01

43

Monthly pan evaporation modeling using linear genetic programming  

NASA Astrophysics Data System (ADS)

We develop monthly pan evaporation predictive models.We utilize linear genetic programming, which has not been applied yet.Our models perform better than blackbox models despite its simpler structure.We propose small empirical formulae driven from the proposed LGP models.This makes LGP models very practical in early design of hydraulic structures.

Guven, Aytac; Kisi, Ozgur

2013-10-01

44

A spatial analysis of pan evaporation trends in China, 1955–2000  

Microsoft Academic Search

Pan evaporation, an indicator of potential evaporation, has decreased during the last several decades in many parts of the world. This trend is contrary to the expectation that global warming will be accompanied by an increase in terrestrial evaporation, known as the pan evaporation paradox. In this paper we present an analysis of changes in the spatial patterns of pan

Binhui Liu; Ming Xu; Mark Henderson; Weiguang Gong

2004-01-01

45

A spatial analysis of pan evaporation trends in China, 1955-2000  

Microsoft Academic Search

Pan evaporation, an indicator of potential evaporation, has decreased during the last several decades in many parts of the world. This trend is contrary to the expectation that global warming will be accompanied by an increase in terrestrial evaporation, known as the pan evaporation paradox. In this paper we present an analysis of changes in the spatial patterns of pan

Binhui Liu; Ming Xu; Mark Henderson; Weiguang Gong

2004-01-01

46

Pan Evaporation, Potential and Actual Evapotranspiration  

Microsoft Academic Search

A formula for estimating the evapotranspiration rate from temperature and relative humidity data is given. Results of some tests of the accuracy of the equation indicate that it is better than other equations based on a similar number of variables. The accuracy was not as good as equations requiring more variables for their utilization, however. It was found from an

Joe R. Eagleman

1967-01-01

47

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

48

Estimation of daily pan evaporation using artificial neural network and multivariate non-linear regression  

Microsoft Academic Search

Measurement of evaporation (E) rate from various natural surfaces is known as the key element in any hydrological cycle and hydrometeorological studies.\\u000a Due to the shortage of pan evaporation (E\\u000a P) data, the estimation of E\\u000a P for such studies seems necessary. The main aim of this paper was to estimate daily E\\u000a P using artificial neural network (ANN) and

Hossein Tabari; Safar Marofi; Ali-Akbar Sabziparvar

2010-01-01

49

Modeling monthly pan evaporations using fuzzy genetic approach  

NASA Astrophysics Data System (ADS)

We estimate monthly pan evaporation (PE) by using fuzzy genetic (FG) approach. FG estimates are compared with neuro-fuzzy (NF) and neural network (NN) techniques. Comparison results indicate the superiority of FG models to the NF and NN models. Models are also compared in estimating one station's PE using nearby station's data. Results reveal that monthly PE can be successfully estimated by FG approach.

Ki?i, Özgür; Tombul, Mustafa

2013-01-01

50

Identification of dominant climate factor for pan evaporation trend in the Tibetan Plateau  

Microsoft Academic Search

Despite the observed increase in global temperature, observed pan evaporation in many regions has been decreasing over the\\u000a past 50 years, which is known as the “pan evaporation paradox”. The “pan evaporation paradox” also exists in the Tibetan Plateau,\\u000a where pan evaporation has decreased by 3.06 mm a?2 (millimeter per annum). It is necessary to explain the mechanisms behind the

Xiaomang Liu; Hongxing Zheng; Minghua Zhang; Changming Liu

2011-01-01

51

Changes of pan evaporation in the upper reach of the Yangtze River  

Microsoft Academic Search

The upper reach of the Yangtze River, 4 511 km long from west to east, contains a great amount of water resources of the Yangtze River Basin. This article studies the characteristics of the pan evaporation, the related meteorological variables, and their effects on the pan evaporation, based on the data of the daily pan evaporation (1980-2008) and other meteorological

Yan-shu RONG; Wen WANG; Hai-yan JIANG

2011-01-01

52

Developing Pan Evaporation to Grass Reference Evapotranspiration Conversion Model a Case Study in Khuzestan Province  

Microsoft Academic Search

In the present study, pan evaporation data and the data required for estimating reference evapotranspiration were collected from 10 meteorological stations in Khuzestan Province using the Penman-Monteith method. Three first, second and third order polynomial models were studied for conversion of pan evaporation data to grass reference evapotranspiration with pan evaporation, wind speed and air humidity as the main variables.

Ali Rahimi Khoob; Seyedmahmoudreza Behbahani; Mohammad Hadi Nazarifar

2007-01-01

53

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

54

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

55

Modeling pan evaporation for Kuwait by multiple linear regression.  

PubMed

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. PMID:23226984

Almedeij, Jaber

2012-11-22

56

A simple pan-evaporation model for analysis of climate simulations: Evaluation over Australia  

Microsoft Academic Search

We show that a simple model of pan evaporation (“PenPan”) can be used to analyze monthly mean output from a global climate model (GCM). PenPan is based on a modified version of Penman's potential evapotranspiration equation. Very good agreement is obtained with observed annual pan evaporation for Australian sites when PenPan is forced by surface observations of radiation, wind speed,

Leon D. Rotstayn; Michael L. Roderick; Graham D. Farquhar

2006-01-01

57

Estimating U.S. Class A Pan Evaporation from Few Climate Data  

Microsoft Academic Search

In view of the shortage of good measurements of lake evaporation for testing a new estimation formula, a modification of the formula has been devised that can be compared with U.S. Class A pan measurements. which are available widely. Both formulae, for lake and pan evaporation respectively, are based on Penman's evaporation equation and are for use when the only

Edward T. Linacre

1994-01-01

58

Applicability of a User-Oriented Evaporation Pan for Low frequency Irrigation of Cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

The evaporation pan is one field device used to support irrigation scheduling. This device integrates environmental effects and measures evaporation to give an indication of crop water use. However, conventional evaporation pans are sometimes difficult to set up, interpret, and access for field read...

59

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

Microsoft Academic Search

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

I. Baneschi; R. Gonfiantini; M. Guidi

2009-01-01

60

Trend in pan evaporation and its attribution over the past 50 years in China  

Microsoft Academic Search

Trends in pan evaporation are widely relevant to the hydrological community as indicators of hydrological and climate change.\\u000a Pan evaporation has been decreasing in the past few decades over many large areas with differing climates globally. This study\\u000a analyzes pan evaporation data from 671 stations in China over the past 50 years in order to reveal the trends of it

Min Liu; Yanjun Shen; Yan Zeng; Changming Liu

2010-01-01

61

Analysis of pan evaporation trend and its impact factors in Guizhou Province  

Microsoft Academic Search

Based on daily meteorological data of 18 observations from 1961 to 2001 within Guizhou Province, Mann-Kendall trend test, correlation analysis and principal component analysis were applied to determine trend of pan evaporation and its relation with meteorological factors (net solar radiation, temperature, relative humid, wind speed etc.). Analysis results demonstrate: pan evaporation presents a significant decrease trend in the 41

QIN Nianxiu; CHEN Xi; XUE Xianwu; ZHANG Zhicai

62

Modeling of daily pan evaporation of Lake E?irdir using data-driven techniques  

Microsoft Academic Search

Gene Expression Programming (GEP) and Radial Basis Function Network (RBFN) models are developed to estimate daily pan evaporation which is an important parameter in hydrological and meteorological studies. Meteorological parameters used to estimate daily pan evaporation from Lake E?irdir at the southwestern part of Turkey are air temperature (Ta), water temperature (Tw), solar radiation (RC )a nd relative humidity (Rh).

O. Terzi

2011-01-01

63

The influence of heat conduction on evaporation from sunken pans in hot, dry environment  

NASA Astrophysics Data System (ADS)

Lateral heat conduction across a large circular sunken pan located in a hot, dry environment is evaluated using a numerical procedure. Heat flow across the sunken pan—adjacent soil boundary is calculated using a two-dimensional soil plane. Calculations show that a large temperature differential across the pan—substrate boundary develops during the entire diurnal cycle during January and July, leading to consistently positive heat flow from the soil towards the sunken pan. Heat conduction across the pan—substrate boundary represents 10 and 34% of net radiation over the sunken pan during July and January, respectively. This additional heat source, which is not available for shallow lakes, increases annual evaporation from the sunken pan by about 5 8% in July and January, respectively. In hot arid environments, a sunken pan will overestimate evaporation from a nearby shallow lake/dam due to a larger surface roughness and consistently positive conduction heat flow across the pan—substrate boundary.

Oroud, I. M.

1998-09-01

64

Evaporation rates for liquid clusters  

Microsoft Academic Search

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

S. Frauendorf

1995-01-01

65

Trends in pan evaporation and actual evapotranspiration across the conterminous U.S.: Paradoxical or complementary?  

Microsoft Academic Search

Pan evaporation (ETpan) has decreased at 64% of pans in the conterminous U.S. over the past half-century. Comparing trends in ETpan and water budget-derived actual evapotranspiration (ET*a), we observe the so-called “Pan Evaporation Paradox,” which we confirm is no more than a manifestation of the complementarity between actual evapotranspiration (ETa) and potential evapotranspiration (ETp). Examining trends in the components of

Michael T. Hobbins; Jorge A. Ramírez; Thomas C. Brown

2004-01-01

66

Evaporation rate of nucleating clusters.  

PubMed

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

Zapadinsky, Evgeni

2011-11-21

67

Variation trends of meteorological variables in the Laoha river basin and their impacts on pan evaporation  

Microsoft Academic Search

Evaporation, which is an important component of water cycle, is a critical variable in determination of local water resources available, and the accuracy of evaporation computation is of vital importance to hydrological simulation. Since pan evaporation is often used in rainfall-runoff simulation, which is mainly by influenced by meteorological variables, it is necessary to investigate the extents to which different

X. Wang

2009-01-01

68

Rate of runaway evaporative cooling  

SciTech Connect

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

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

2011-09-15

69

Changes of pan evaporation and reference evapotranspiration in the Yangtze River basin  

Microsoft Academic Search

Summary  For the upper and mid-lower Yangtze River basin trends of pan evaporation and reference evapotranspiration are analysed from\\u000a 1961 to 2000 using daily data of 115 stations. Both pan evaporation and reference evapotranspiration decreased during the\\u000a summer months contributing most to the total annual reduction. This trend is more significant in the mid-lower than in the\\u000a upper Yangtze reaches. The

Y. Wang; T. Jiang; O. Bothe; K. Fraedrich

2007-01-01

70

Important factors governing the incompatible trends of annual pan evaporation: evidence from a small scale region  

Microsoft Academic Search

Many studies reported the coexisting trends of decreasing and increasing pan evaporation in some large scale regions. This\\u000a study proved that the coexisting trends also occurred in small scale region as well as in large scale region. To discover\\u000a the important factors governing the incompatible trends of annual pan evaporation, annual climatic data of ten meteorological\\u000a stations at the Liaohe

Yuhe Ji; Guangsheng Zhou

2011-01-01

71

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

Microsoft Academic Search

The objective of this study was to test an artificial neural network (ANN) for estimating the evaporation from pan (E\\u000a Pan) as a function of air temperature data in the Safiabad Agricultural Research Center (SARC) located in Khuzestan plain in\\u000a the southwest of Iran. The ANNs (multilayer perceptron type) were trained to estimate E\\u000a Pan as a function of the

Ali Rahimikhoob

2009-01-01

72

Variation trends of meteorological variables in the Laoha river basin and their impacts on pan evaporation  

NASA Astrophysics Data System (ADS)

Evaporation, which is an important component of water cycle, is a critical variable in determination of local water resources available, and the accuracy of evaporation computation is of vital importance to hydrological simulation. Since pan evaporation is often used in rainfall-runoff simulation, which is mainly by influenced by meteorological variables, it is necessary to investigate the extents to which different meteorological variables affect pan evaporation. The aim of this paper is to explore the variation trends of different meteorological variables, including air temperature, net radiation, relative humidity, wind speed, and their impacts on pan evaporation. This paper selected one subbasin of the Laoha river basin (i.e. Chutoulang) as case study site. The Laoha river basin is situated located in a semi-arid and semi-humid region between latitudes of 40.9°and 42.9°North and between longitudes of 117.2° and 120° East. Chutoulang subbasin is located in the northern Laoha River Basin with a catchment of 3,009 km2, an average annul rainfall of 370mm and an average annul evaporation of 910mm (E601). Based on the daily observed meteorological data from closer meteorological stations during 1970 to 2005, the inverse distance-squared weighted method was used to obtain the meteorological data where evaporation station is situated. Annual and seasonal values of air temperature, net radiation, relative humidity, wind speed, and pan evaporation were computed and the variation trends were analyzed by the nonparametric Mann-Kendall test. The correlation between pan evaporation and each meteorological variable at different scales (i.e. annual and seasonal scales) was analyzed respectively. The results revealed that annual and seasonal pan evaporation and wind speed show decreasing trends, whereas the changing trends of air temperature, net radiation and relative humidity vary with time scales and seasons. Among the meteorological variables, wind speed and relative humidity are the key factors that affect pan evaporation, and the impacts of other meteorological variables on pan evaporation are not significant and vary with time scales and seasons. The output of this paper provides a valuable reference for the forecast of future water resource available, evaporation computation and the sustainable development and utilization of water resources in the Laoha river basin.

Wang, X.

2009-12-01

73

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

Microsoft Academic Search

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

Nurtaç Canpolat

2006-01-01

74

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

ERIC Educational Resources Information Center

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

Canpolat, Nurtac

2006-01-01

75

Estimating daily pan evaporation using adaptive neural-based fuzzy inference system  

NASA Astrophysics Data System (ADS)

Estimation of evaporation is important for water planning, management, and hydrological practices. There are many available methods to estimate evaporation from a water surface, comprising both direct and indirect methods. All the evaporation models are based on crisp conceptions with no uncertainty element coupled into the model structure although in daily evaporation variations there are uncontrollable effects to a certain extent. The probabilistic, statistical, and stochastic approaches require large amounts of data for the modeling purposes and therefore are not practical in local evaporation studies. It is therefore necessary to adopt a better approach for evaporation modeling, which is the fuzzy sets and adaptive neural-based fuzzy inference system (ANFIS) as used in this paper. ANFIS and fuzzy sets have been evaluated for its applicability to estimate evaporation from meteorological data which is including air and water temperatures, solar radiation, and air pressure obtained from Automated GroWheather meteorological station located near Lake E?irdir and daily pan evaporation values measured by XVIII. District Directorate of State Hydraulic Works. Results of ANFIS and fuzzy logic approaches were analyzed and compared with measured daily pan evaporation values. ANFIS approach could be employed more successfully in modeling the evaporation process than fuzzy sets.

Keskin, M. Erol; Terzi, Özlem; Taylan, Dilek

2009-09-01

76

Artificial neural network estimation of reference evapotranspiration from pan evaporation in a semi-arid environment  

Microsoft Academic Search

The objective of this study was to test an artificial neural network (ANN) for converting pan evaporation data (E\\u000a p) to estimate reference evapotranspiration (ET0) as a function of the maximum and minimum air temperature. The conventional method that uses Pan coefficient (K\\u000a p) as a factor to convert E\\u000a p to ET0, is also considered for the comparison. The

Ali Rahimi Khoob

2008-01-01

77

A Comparative Study of Daily Pan Evaporation Estimation Using ANN, Regression and Climate Based Models  

Microsoft Academic Search

Evaporation estimates are needed for efficient management of water resources at a farm scale as well as at a regional or catchment\\u000a scale. This paper presents application of artificial neural networks (ANN), statistical regression and climate based models\\u000a viz.: Penman, Priestley–Taylor and Stephens and Stewart, for estimation of daily pan evaporation. Six different measured weather\\u000a variables comprising various combinations of

Paresh Bhaskar Shirsath; Anil Kumar Singh

2010-01-01

78

Fuel evaporation rate in intense recirculation zones  

Microsoft Academic Search

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

I. T. Osgerby

1975-01-01

79

An explanation for decreasing trends in pan evaporation based on research on interactions between surface evaporation and the atmospheric boundary layer  

Microsoft Academic Search

The explanation for decreasing trends in long term data sets of pan evaporation has been the subject of many studies over the last two decades. In this research, we formulated a theory that explains the trends in pan evaporation, radiation, temperature and vapor pressure deficit consistently, considering all interactions and feedbacks between the land surface and the atmospheric boundary layer.

J. Vila; C. van Heerwaarden

2009-01-01

80

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 conceptual models of potential evaporation of Penman, Penman-Monteith and Priestley-Taylor, and discussions of reference crop evaporation and then 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) hard-wired evaporation estimates, (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 supplementary material that includes 21 appendices 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.

2012-10-01

81

Trends in Pan Evaporation and Application of the Complimentary Relationship of Evaporation in the Great Basin, USA  

NASA Astrophysics Data System (ADS)

Evaluating available water resources in the Great Basin is an increasing topic of discussion by several local, State, and Federal government agencies due to proposals for water importation into areas of rapid population growth. In estimating a water budget for a particular flow system in the Great Basin, groundwater evapotranspiration (ET) from phreatophyte vegetation is often the most important as it is the only water budget component that can be estimated with some certainty, opposed to mountain block recharge and interbasin subsurface flow. Bouchet's complimentary relationship of evaporation has drawn noteworthy attention in recent years, not only because of its use in explaining observed changes in the hydrologic cycle, but also for its use in predicting ET using readily available meteorological data. The objective of this presentation is twofold: 1) to discuss pan evaporation trends in the Great Basin, and 2) discuss results from the application of the complimentary relationship for predicting evapotranspiration from phreatophyte shrubs when compared to measured ET at several U.S. Geological Survey eddy correlation and Bowen ratio sites. Initial findings indicate a decrease of pan evaporation in Death Valley, CA, the lowest, hottest, and driest location in North America, an opposite trend from analysis of several other sites in the Great Basin that indicate an increase of pan evaporation. It is believed that these opposing trends are likely the result of local water availability surrounding the pan, and or data quality. The application of a symmetric complimentary relationship indicate satisfactory results when compared to measured evapotranspiration, however, during the hottest months of the year the predicted ET over estimates the measured. Further investigation of micrometeorological data suggests that an asymmetric complimentary relationship between potential and actual ET exists, and when taken into account, improves the predictions markedly.

Huntington, J. L.; Caldwell, T.; Naranjo, R.; Burak, S.; Tyler, S.

2007-12-01

82

Changes of Pan Evaporation in the Recent 40 Years in the Yellow River Basin  

Microsoft Academic Search

Based on monitoring data of 123 meteorological stations from 1960 to 2000 near or in the Yellow River Basin, the spatial and temporal distributions and their trends for pan evaporation (PE) are investigated in this study. The results indicate that, despite the annual mean air temperature over the Yellow River Basin has, on average, increased by 0.6° over the past

Changming Liu; Yan Zeng

2004-01-01

83

Estimates of Pan Evaporation from Mean Maximum Temperature and Vapor Pressure  

Microsoft Academic Search

An equation for estimating pan evaporation has been derived by regression analysis from climatic data of a number of widely separated stations in Australia. The required data are mean maximum temperature, mean vapor pressure, and day length. The equation resembles the bulk aerodynamic (mass transfer) expression, but does not contain a wind parameter.An empirical variate was postulated and compared with

Eugene A. Fitzpatrick

1963-01-01

84

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

85

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

86

Evaporation rate of water in hydrophobic confinement.  

PubMed

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

Sharma, Sumit; Debenedetti, Pablo G

2012-03-05

87

Irrigation of potatoes by sprinklers or tricklers on the basis of pan evaporation in a semi-arid region  

Microsoft Academic Search

Both the amount and frequency of irrigation were based on evaporation from a screened USWB Class A pan. From the time tuber initiation had been completed, and full cover had been attained (about 60 days after planting), until the crop was lifted, 40–60 days later, sprinkler irrigation with the equivalent of 0.7–0.8 of pan evaporation was sufficient for maximum yields.

Y. Stylianou; P. I. Orphanos

1981-01-01

88

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

89

Evaporation rate of nucleating clusters  

Microsoft Academic Search

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

Evgeni Zapadinsky

2011-01-01

90

A calorimeter for measuring liquid evaporation rates  

Microsoft Academic Search

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

C. A. Reading; A. Reiser

1977-01-01

91

Surface acoustic wave measurements of evaporation rate  

Microsoft Academic Search

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

Pavol Koštial

1996-01-01

92

An explanation for decreasing trends in pan evaporation based on research on interactions between surface evaporation and the atmospheric boundary layer  

NASA Astrophysics Data System (ADS)

The explanation for decreasing trends in long term data sets of pan evaporation has been the subject of many studies over the last two decades. In this research, we formulated a theory that explains the trends in pan evaporation, radiation, temperature and vapor pressure deficit consistently, considering all interactions and feedbacks between the land surface and the atmospheric boundary layer. To be able to do this, we used a coupled land-atmosphere model to perform a large set of simulations. We evaluated the two existing hypotheses for the decreasing trends: an accelerated hydrologic cycle due to global warming, and global dimming. For this evaluation we have set up our coupled land-atmosphere model to reproduce the surface evaporation, atmospheric temperature, humidity and wind for a characteristic day at the Southern Great Plains, USA. Based on the model output we calculated the daily evaporation, the daily pan evaporation and the average vapor pressure deficit over that day, which we use in our analysis. Subsequently, we created a large set of scenarios that could mimic the effects of global warming, an increased hydrologic cycle and global dimming, by modifying the initial or boundary conditions of our model runs. The collection of model runs allows us to perform an analysis of each of the three elements of climate change separately and of combination of the elements. The most important finding is that over large parts of the USA the enhanced hydrologic cycle is the dominant cause of decreasing pan evaporation and that the effects of global dimming are only marginal. Our analysis shows that evaporation must have increased over the region to be consistent with the measurements of vapor pressure deficit. However, in conditions which are typically found in large parts of China, the opposite effect is found. Here, there is barely an accelerated hydrologic cycle and global dimming causes a decrease in both pan and actual evaporation.

Vila, J.; van Heerwaarden, C.

2009-12-01

93

Evaporation rate of volatile liquids. Final report, Second edition  

Microsoft Academic Search

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

K. O. Braun; K. J. Caplan

1989-01-01

94

Evaporation Rate of Liquid Helium. I  

Microsoft Academic Search

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

Aaron Wexler

1951-01-01

95

Experimental determination of sodium evaporation rates. [LMFBR  

Microsoft Academic Search

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

W. Schuetz; H. Sauter

1982-01-01

96

Spatio-temporal variations of reference crop evapotranspiration and pan evaporation in the West Songnen Plain of China  

Microsoft Academic Search

The spatio-temporal variations of reference crop evapotranspiration (ETref) reflect the combined effects of meteorological variables, primarily wind speed, relative humidity, net radiation and air temperature. This study investigated the spatial distribution and temporal trends of ETref (calculated by the FAO-56 Penman-Monteith equation), pan evaporation (Epan) and pan coefficient (Kp) in a 140?×?10 km semi-humid to semi-arid area in China. The

Liqiao Liang; Lijuan Li; Qiang Liu

2011-01-01

97

A comparative study on the estimation of evapotranspiration using backpropagation neural network: Penman–Monteith method versus pan evaporation method  

Microsoft Academic Search

The study compares the prediction performances of evapotranspiration by the FAO56 Penman–Monteith method and the pan evaporation\\u000a method using the artificial neural network. A backpropagation neural network was adopted to determine the relationship between\\u000a meteorological factors and evapotranspiration or evaporation. The evapotranspiration in the ChiaNan irrigated area of Tainan\\u000a was considered. Weather data compiled by Irrigation Experiment Station of ChiaNan

Sheng-Feng Kuo; Feng-Wen Chen; Pei-Yu Liao; Chen-Wuing Liu

98

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

99

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

100

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

101

Statistical downscaling of daily mean temperature, pan evaporation and precipitation for climate change scenarios in Haihe River of China  

NASA Astrophysics Data System (ADS)

The applicability of the Statistical DownScaling Method (SDSM) in the Haihe River basin of China was evaluated, and its strengths and weaknesses in simultaneously downscaling air temperature, evaporation and precipitation were discussed. The used large scale atmospheric data were daily NCEP/NCAR reanalysis data and the daily emissions scenarios A2 and B2 of the HadCM3 model. Measured daily mean air temperature, pan evaporation and precipitation data (1961-2000) from 11 weather stations in the Haihe River basin were selected as climate variables to be downscaled. The results showed that: (1) the amount and change pattern of the climate variables could be reasonably simulated; the determination coefficients between observed and downscaled mean temperature, pan evaporation and precipitation were 99%, 93% and 73%, respectively; (2) there were some systematic errors in simulating extreme events, but the results were considered to be acceptable for practical use; and (3) in the future 2011~2040, the mean air temperature would increase about 0.6°C; there were no obvious changes in pan evaporation, and the total annual precipitation would decrease by about 4?. It was concluded that in the future 30 years, the climate would be warmer and drier, extreme events could be more intense, and the autumn might be the most distinct season for all of these changes.

Chu, J.

2009-04-01

102

Statistical downscaling of daily mean temperature, pan evaporation and precipitation for climate change scenarios in Haihe River, China  

NASA Astrophysics Data System (ADS)

A statistical downscaling method (SDSM) was evaluated by simultaneously downscaling air temperature, evaporation, and precipitation in Haihe River basin, China. The data used for evaluation were large-scale atmospheric data encompassing daily NCEP/NCAR reanalysis data and the daily mean climate model results for scenarios A2 and B2 of the HadCM3 model. Selected as climate variables for downscaling were measured daily mean air temperature, pan evaporation, and precipitation data (1961-2000) from 11 weather stations in the Haihe River basin. The results obtained from SDSM showed that: (1) the pattern of change in and numerical values of the climate variables can be reasonably simulated, with the coefficients of determination between observed and downscaled mean temperature, pan evaporation, and precipitation being 99%, 93%, and 73%, respectively; (2) systematic errors existed in simulating extreme events, but the results were acceptable for practical applications; and (3) the mean air temperature would increase by about 0.7°C during 2011~2040; the total annual precipitation would decrease by about 7% in A2 scenario but increase by about 4% in B2 scenario; and there were no apparent changes in pan evaporation. It was concluded that in the next 30 years, climate would be warmer and drier, extreme events could be more intense, and autumn might be the most distinct season among all the changes.

Chu, J. T.; Xia, J.; Xu, C.-Y.; Singh, V. P.

2010-01-01

103

Utility of coactive neuro-fuzzy inference system for pan evaporation modeling in comparison with multilayer perceptron  

NASA Astrophysics Data System (ADS)

Estimation of pan evaporation ( E pan) using black-box models has received a great deal of attention in developing countries where measurements of E pan are spatially and temporally limited. Multilayer perceptron (MLP) and coactive neuro-fuzzy inference system (CANFIS) models were used to predict daily E pan for a semi-arid region of Iran. Six MLP and CANFIS models comprising various combinations of daily meteorological parameters were developed. The performances of the models were tested using correlation coefficient ( r), root mean square error (RMSE), mean absolute error (MAE) and percentage error of estimate (PE). It was found that the MLP6 model with the Momentum learning algorithm and the Tanh activation function, which requires all input parameters, presented the most accurate E pan predictions ( r = 0.97, RMSE = 0.81 mm day-1, MAE = 0.63 mm day-1 and PE = 0.58 %). The results also showed that the most accurate E pan predictions with a CANFIS model can be achieved with the Takagi-Sugeno-Kang (TSK) fuzzy model and the Gaussian membership function. Overall performances revealed that the MLP method was better suited than CANFIS method for modeling the E pan process.

Tabari, Hossein; Hosseinzadeh Talaee, P.; Abghari, Hirad

2012-05-01

104

Undersaturation dependence of the evaporation rate of potassium chloride  

Microsoft Academic Search

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

Paul C. Nordine; Paul W. Gilles

1981-01-01

105

Characteristics of climatic trends and correlation between pan-evaporation and environmental factors in the last 40 years over China  

Microsoft Academic Search

Using the data observed by 62 Chinese Routine Meteorological Stations (CRMS) with long term radiation observation, the climatic\\u000a trends and the relationship between pan-evaporation and its environmental factors are analyzed comprehensively. The results\\u000a show that during the last 40 years, the relative humidity is uptrend in west China, downtrend in east China, and their extrema\\u000a are 0.20%\\/a and ?0.22 %\\/a

Hongchao Zuo; Dongliang Li; Yinqiao Hu; Yan Bao; Shihua Lü

2005-01-01

106

Estimating daily pan evaporation using adaptive neural-based fuzzy inference system  

Microsoft Academic Search

Estimation of evaporation is important for water planning, management, and hydrological practices. There are many available\\u000a methods to estimate evaporation from a water surface, comprising both direct and indirect methods. All the evaporation models\\u000a are based on crisp conceptions with no uncertainty element coupled into the model structure although in daily evaporation\\u000a variations there are uncontrollable effects to a certain

M. Erol Keskin; Özlem Terzi; Dilek Taylan

2009-01-01

107

Does evaporation paradox exist in China?  

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

108

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

109

Predicting evaporation rates and times for spills of chemical mixtures  

Microsoft Academic Search

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

RAYMOND L. SMITH

2001-01-01

110

Instructions for measuring the rate of evaporation from water surfaces  

USGS Publications Warehouse

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

U.S. Geological Survey

1898-01-01

111

Pan evaporation and wind run decline in the Cape Floristic Region of South Africa (1974–2005): implications for vegetation responses to climate change  

Microsoft Academic Search

In many regions of the world, increasing temperatures in recent decades are paradoxically associated with declining pan evaporation,\\u000a but evidence is sparse for this trend from the southern hemisphere in general and sub-Saharan Africa in particular. In this\\u000a study, we examined changes in pan evaporation and four other meteorological variables (rainfall, wind run, temperature and\\u000a vapour pressure deficit) at 20

M. Timm Hoffman; Michael D. Cramer; Lindsey Gillson; Michael Wallace

2011-01-01

112

Daily pan evaporation modelling using a neuro-fuzzy computing technique  

Microsoft Academic Search

Evaporation, as a major component of the hydrologic cycle, is important in water resources development and management. This paper investigates the abilities of neuro-fuzzy (NF) technique to improve the accuracy of daily evaporation estimation. Five different NF models comprising various combinations of daily climatic variables, that is, air temperature, solar radiation, wind speed, pressure and humidity are developed to evaluate

Özgür Kisi

2006-01-01

113

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

114

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

Microsoft Academic Search

Abstract 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-Taylormethods,are based

M. Erol Keskin; Özlem Terzi; Dilek Taylan

115

Wettability and the evaporation rates of fluids from solid surfaces  

Microsoft Academic Search

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

K. S. Birdi; D. T. Vu

1993-01-01

116

Experimental study on isotopic fractionation factor and evaporation rate  

Microsoft Academic Search

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

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

2009-01-01

117

Monthly Reservoir Evaporation Rates for Texas, 1940 Through 1965.  

National Technical Information Service (NTIS)

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

J. W. Kane

1967-01-01

118

Evaporation rate as a function of water salinity  

Microsoft Academic Search

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

M. Al-Shammiri

2002-01-01

119

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

120

Utility of Penman-Monteith, Priestley-Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration  

USGS Publications Warehouse

Actual evapotranspiration (ETa) was measured at 30-min resolution over a 19-month period (September 28, 2000-April 23, 2002) from a nonirrigated pasture site in Florida, USA, using eddy correlation methods. The relative magnitude of measured ETa (about 66% of long-term annual precipitation at the study site) indicates the importance of accurate ET a estimates for water resources planning. The time and cost associated with direct measurements of ETa and the rarity of historical measurements of ETa make the use of methods relying on more easily obtainable data desirable. Several such methods (Penman-Monteith (PM), modified Priestley-Taylor (PT), reference evapotranspiration (ET 0), and pan evaporation (Ep)) were related to measured ETa using regression methods to estimate PM bulk surface conductance, PT ??, ET0 vegetation coefficient, and Ep pan coefficient. The PT method, where the PT ?? is a function of green-leaf area index (LAI) and solar radiation, provided the best relation with ET a (standard error (SE) for daily ETa of 0.11 mm). The PM method, in which the bulk surface conductance was a function of net radiation and vapor-pressure deficit, was slightly less effective (SE=0.15 mm) than the PT method. Vegetation coefficients for the ET0 method (SE=0.29 mm) were found to be a simple function of LAI. Pan coefficients for the Ep method (SE=0.40 mm) were found to be a function of LAI and Ep. Historical or future meteorological, LAI, and pan evaporation data from the study site could be used, along with the relations developed within this study, to provide estimates of ETa in the absence of direct measurements of ETa. Additionally, relations among PM, PT, and ET0 methods and ETa can provide estimates of ETa in other, environmentally similar, pasture settings for which meteorological and LAI data can be obtained or estimated. ?? 2004 Elsevier B.V. All rights reserved.

Sumner, D. M.; Jacobs, J. M.

2005-01-01

121

Impact of nitric acid on ice evaporation rates  

Microsoft Academic Search

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

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

1999-01-01

122

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

National Technical Information Service (NTIS)

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

K. J. Caplan K. O. Braun

1989-01-01

123

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

Microsoft Academic Search

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

N. Shokri; D. Or

2011-01-01

124

Measurement of Evaporation from Lakes and Ponds in Florida.  

National Technical Information Service (NTIS)

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

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

1978-01-01

125

Impact of nitric acid on ice evaporation rates  

NASA Astrophysics Data System (ADS)

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

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

126

Comparison of artificial neural network and empirical equations for daily reference evapotranspiration estimation from pan evaporation  

Microsoft Academic Search

Evaporation and Evapotranspiration Process are the major components of the hydrologic cycle which play an important role in agricultural studies such as design of irrigation and drainage systems, and irrigation scheduling. Evapotranspiration is a complex non-linear phenomenon which depends on several climatologic factors. It can be measured directly by high-cost micrometeorological techniques. Hence, many mathematical models and empirical equations were

Abolfazl Mosaedi; Mohammad Ghabaei S

2010-01-01

127

Trends in pan evaporation and reference and actual evapotranspiration across the Tibetan Plateau  

Microsoft Academic Search

The Tibetan Plateau is one of the areas of the world where humans have had a relatively minor impact. The plateau thus provides ideal conditions for investigating evapotranspiration (In this paper, evapotranspiration terms are defined as follows: (1) “Actual evapotranspiration” includes evaporation from water and soil and transpiration from the vegetation of a specific region; (2) “potential evapotranspiration” includes the

Yongqiang Zhang; Changming Liu; Yanhong Tang; Yonghui Yang

2007-01-01

128

Trends in pan evaporation and reference and actual evapotranspiration across the Tibetan Plateau  

Microsoft Academic Search

The Tibetan Plateau is one of the areas of the world where humans have had a relatively minor impact. The plateau thus provides ideal conditions for investigating evapotranspiration (In this paper, evapotranspiration terms are defined as follows: (1) ``Actual evapotranspiration'' includes evaporation from water and soil and transpiration from the vegetation of a specific region; (2) ``potential evapotranspiration'' includes the

Yongqiang Zhang; Changming Liu; Yanhong Tang; Yonghui Yang

2007-01-01

129

Surface heat balance and pan evaporation trends in Eastern Asia in the period 1971-2000  

Microsoft Academic Search

Climatic variations over Eastern Asia, including the Tibetan Plateau, were analysed using meteorological data for 32 points in the period 1971 to 2000. Changes in heat and water balances were examined using potential evaporation EP, and a wetness index WI, as suggested by Kondo and Xu ([1997a,b]). Climate zones, including the humid, semi-humid, semi-arid and arid climate types, in Eastern

Jianqing Xu; Shigenori Haginoya; Kazuyuki Saito; Ken Motoya

2005-01-01

130

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

Microsoft Academic Search

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

Gavalas

1962-01-01

131

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

132

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

133

APPRAISAL OF SEASONAL VARIATION IN PAN COEFFICIENTS  

Microsoft Academic Search

SUMMARY The purpose ot this paper is to clarify the application of pan evaporation coeffi­ cients to obtain estimates of lake evaporation. Reliable estimates of annual lake evaporation may usually be obtained by use of annual pan evaporation and the appropriate pan coefficient. It is more difficult to derive accurate monthly values of lake evaporation from monthly pan evaporation data.

Tor J. NORDENSON

134

Measurement of Evaporation Rates of Organic Liquids by Optical Interference  

Microsoft Academic Search

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

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

1997-01-01

135

Experimental Determination of Liquid Evaporation Rates in Superheated Fluidized Beds  

Microsoft Academic Search

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

W. K. Gu; John C. Chen

1997-01-01

136

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

137

Measuring Evaporation Rates of Methane Under Simulated Titan Conditions  

Microsoft Academic Search

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

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

2011-01-01

138

The Rate of Evaporation of Liquids in a Current of Air  

Microsoft Academic Search

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

T. B. Hine

1924-01-01

139

Priority of the Mn Deposition Rate in Reactive Evaporation Conditions  

NASA Astrophysics Data System (ADS)

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

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

2000-12-01

140

Evaporation  

NSDL National Science Digital Library

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

141

Calculation of Reactive-evaporation Rates of Chromia  

SciTech Connect

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

Holcomb, G.R.

2008-04-01

142

Does evaporation paradox exist in China?  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

143

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

Microsoft Academic Search

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

Zdzis?aw Kawala; Pawe? Dakiniewicz

2002-01-01

144

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

PubMed

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

Dandan, Merve; Erbil, H Yildirim

2009-07-21

145

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

Microsoft Academic Search

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

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

2009-01-01

146

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

Microsoft Academic Search

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

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

1993-01-01

147

Does evaporation paradox exist in China?  

Microsoft Academic Search

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

Z. T. Cong; D. W. Yang

2008-01-01

148

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

Microsoft Academic Search

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

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

2009-01-01

149

Evaporation Correction Methods for Microwave Retrievals of Surface Precipitation Rate  

Microsoft Academic Search

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

Chinnawat Surussavadee; David H. Staelin

2011-01-01

150

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

151

Henry's law and hydrolysis-rate constants for peroxyacyl nitrates (PANs) using a homogeneous gas-phase source  

Microsoft Academic Search

The solubilities and hydrolysis rates of PAN (peroxyacetyl nitrate) and its homologues PPN (peroxypropionyl nitrate), PnBN (peroxy-n-butyl nitrate), PiBN (peroxy-isobutyl nitrate) and MPAN (peroxymethacryloyl nitrate) in liquid water have been studied at 20 °C. Temperature dependencies were measured for PAN and PPN. The solubilities of peroxyacyl nitrates decrease smoothly with increasing carbon-chain length fromH (293 K)=4.1 M atm-1 (PAN) toH

Jost Kames; Ulrich Schurath

1995-01-01

152

Evaporation rates of alkanes and alkanols from acoustically levitated drops  

Microsoft Academic Search

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

Rudolf Tuckermann; Sigurd Bauerecker; Bernd Neidhart

2002-01-01

153

Subjective assessment of chimpanzee (Pan troglodytes) personality: reliability and stability of trait ratings.  

PubMed

A 46-item rating scale was used to obtain personality ratings from 75 captive chimpanzees (Pan troglodytes) from 7 zoological parks. Factor analysis revealed five personality dimensions similar to those found in previous research on primate personality: Agreeableness, Dominance, Neuroticism, Extraversion and Intellect. There were significant sex and age differences in ratings on these dimensions, with males rated more highly on Dominance and older chimpanzees rated as more agreeable but less extraverted than younger chimpanzees. Interobserver agreement for most individual trait items was high, but tended to be less reliable for trait terms expressing more subtle social or cognitive abilities. Personality ratings for one zoo were found to be largely stable across a 3-year period, but highlighted the effects of environmental factors on the expression of personality in captive chimpanzees. PMID:18668303

Dutton, Diane M

2008-08-01

154

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

Microsoft Academic Search

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

P. Hanzelka; V. Musilová

1995-01-01

155

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

Microsoft Academic Search

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

Joseph T. Zung

1967-01-01

156

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

NASA Astrophysics Data System (ADS)

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

Shahraeeni, E.; Or, D.

2010-12-01

157

Statistical downscaling of daily mean temperature, pan evaporation and precipitation for climate change scenarios in Haihe River of China  

Microsoft Academic Search

The applicability of the Statistical DownScaling Method (SDSM) in the Haihe River basin of China was evaluated, and its strengths and weaknesses in simultaneously downscaling air temperature, evaporation and precipitation were discussed. The used large scale atmospheric data were daily NCEP\\/NCAR reanalysis data and the daily emissions scenarios A2 and B2 of the HadCM3 model. Measured daily mean air temperature,

J. Chu

2009-01-01

158

Statistical downscaling of daily mean temperature, pan evaporation and precipitation for climate change scenarios in Haihe River, China  

Microsoft Academic Search

A statistical downscaling method (SDSM) was evaluated by simultaneously downscaling air temperature, evaporation, and precipitation in Haihe River basin, China. The data used for evaluation were large-scale atmospheric data encompassing daily NCEP\\/NCAR reanalysis data and the daily mean climate model results for scenarios A2 and B2 of the HadCM3 model. Selected as climate variables for downscaling were measured daily mean

J. T. Chu; J. Xia; C.-Y. Xu; V. P. Singh

2010-01-01

159

Statistical downscaling of daily mean temperature, pan evaporation and precipitation for climate change scenarios in Haihe River, China  

Microsoft Academic Search

A statistical downscaling method (SDSM) was evaluated by simultaneously downscaling air temperature, evaporation, and precipitation\\u000a in Haihe River basin, China. The data used for evaluation were large-scale atmospheric data encompassing daily NCEP\\/NCAR reanalysis\\u000a data and the daily mean climate model results for scenarios A2 and B2 of the HadCM3 model. Selected as climate variables for\\u000a downscaling were measured daily mean

J. T. Chu; J. Xia; C.-Y. Xu; V. P. Singh

2010-01-01

160

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

Microsoft Academic Search

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

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

2000-01-01

161

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

162

Experimental determination of fuel evaporation rates using IR-Thermography  

Microsoft Academic Search

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

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

163

Physically modeling operative temperatures and evaporation rates in amphibians  

USGS Publications Warehouse

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

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

2005-01-01

164

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

Microsoft Academic Search

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

K. Srithar; A. Mani

2007-01-01

165

Does evaporation paradox exist in China?  

Microsoft Academic Search

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

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

2009-01-01

166

Modern Evaporation Formulae Adapted to Computer Use  

Microsoft Academic Search

Several graphical solutions for computing pan and lake evaporation have been published, ljiit because of the advantages of using a high-speed digital computer in processing masses of data, the graphical representations by Kohler et al. are reduced to mathematical expressions adaptable to computer use and in terms of readily available input data. A measure of the evaporation rat'e has long

Wallace W. Lamoreux

1962-01-01

167

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

National Technical Information Service (NTIS)

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

T. A. Donnelly

2007-01-01

168

On laboratory simulation and the evaporation rate of water on Mars  

Microsoft Academic Search

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

Derek W. G. Sears; Shauntae R. Moore

2005-01-01

169

Witnessing Evaporation  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

170

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

NASA Astrophysics Data System (ADS)

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

Sharma, Sumit; Debenedetti, Pablo G.

2012-02-01

171

Orientation Dependence of the Evaporation Rate of CdS Single Crystals  

Microsoft Academic Search

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

G. A. Somorjai; N. R. Stemple

1964-01-01

172

Oil shale process water evaporation  

SciTech Connect

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

Hasfurther, V.R.; Reeves, T.

1990-01-01

173

Measurement of the Henry's law coefficient and first order loss rate of PAN in n-octanol  

NASA Astrophysics Data System (ADS)

The Henry's Law solubility and first order loss rates of PAN (peroxyacetic nitric anhydride, CH3C(O)OONO2) in a model non-polar solvent, n-octanol, were measured for a range of temperatures pertinent to the lower troposphere (273-298 °K). The solubility was found to be factors of 6 to 12 higher than those measured previously for pure water, ranging between 110 +/- 7.5 M/atm at 273°K and 34 +/- 1.7 M/atm at 298°K. The loss rates were found to vary from below 0.5 × 10-5 sec-1 at 273°K to 5.2 +/- 1.9 × 10-5 sec-1 at 298°K. Several simple approaches were used to estimate that the uptake of PAN on organic aerosol has a negligible impact on ambient PAN concentrations.

Roberts, James M.

2005-04-01

174

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

NASA Astrophysics Data System (ADS)

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

Shokri, N.; Or, D.

2011-09-01

175

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

Microsoft Academic Search

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

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

1999-01-01

176

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

NASA Astrophysics Data System (ADS)

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

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

1992-02-01

177

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

Microsoft Academic Search

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

Maw Tien Lee; Jer Ru Maa

1992-01-01

178

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

Microsoft Academic Search

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

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

1976-01-01

179

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

180

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

181

Evaporation rate and composition monitoring of electron beam PVD processes  

SciTech Connect

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

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

1995-03-01

182

Finite size effects in the evaporation rate of 3 He clusters  

Microsoft Academic Search

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

A. Guirao; M. Pi; M. Barranco

1991-01-01

183

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

Microsoft Academic Search

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

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

2010-01-01

184

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

Microsoft Academic Search

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

J. P. Kunsch

1998-01-01

185

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

Microsoft Academic Search

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

A. Dvorjetski; J. B. Greenberg

2002-01-01

186

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

Microsoft Academic Search

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

Juergen Nahstoll

1988-01-01

187

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

Microsoft Academic Search

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

N. Roth; J. Wilms; B. Weigand

188

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

Microsoft Academic Search

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

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

2006-01-01

189

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

Microsoft Academic Search

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

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

1993-01-01

190

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

Microsoft Academic Search

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

D. Saury; S. Harmand; M. Siroux

2005-01-01

191

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

EPA Science Inventory

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

192

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...

193

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

SciTech Connect

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

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

2007-06-15

194

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

NASA Astrophysics Data System (ADS)

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

Nahstoll, Juergen

1988-01-01

195

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

USGS Publications Warehouse

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

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

1970-01-01

196

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

197

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

Microsoft Academic Search

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

Kenneth K. Chao; Costandy S. Saba

1997-01-01

198

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

Microsoft Academic Search

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

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

1993-01-01

199

Peter Pan.  

ERIC Educational Resources Information Center

|Offers a contemporary view of J. M. Barrie's life and his classic story, "Peter Pan." Suggests that "Peter Pan" does not really speak for today's children and that the time for Peter Pan's retirement has come. (PRA)|

Storr, Catherine

1992-01-01

200

Reservoir evaporation in central Colorado  

USGS Publications Warehouse

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

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

1983-01-01

201

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

Microsoft Academic Search

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

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

2010-01-01

202

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

Microsoft Academic Search

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

Derek W. G. Sears; Julie D. Chittenden

2005-01-01

203

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

Microsoft Academic Search

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

Derek W. G. Sears; Julie D. Chittenden

2005-01-01

204

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

Microsoft Academic Search

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

Yang Wanqin; Wang Kaiyun; Seppo Kellomäki; Xiao Ling

2004-01-01

205

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

NASA Astrophysics Data System (ADS)

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

Tsuang, Ben Jei

206

Exploring Evaporation  

NSDL National Science Digital Library

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

Eichinger, John

2009-05-15

207

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

208

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

209

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

Microsoft Academic Search

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

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

2001-01-01

210

New limit on the rate-density of evaporating black holes  

NASA Astrophysics Data System (ADS)

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

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

1993-10-01

211

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

NASA Astrophysics Data System (ADS)

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

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

1993-05-01

212

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

SciTech Connect

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

The CYGNUS Collaboration

1993-05-01

213

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

SciTech Connect

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

Not Available

1993-01-01

214

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

SciTech Connect

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

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

2012-03-12

215

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

SciTech Connect

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

Bourillot, C.

1983-08-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

217

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

218

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

NASA Astrophysics Data System (ADS)

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

Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

2013-08-01

219

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

Microsoft Academic Search

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

R. A. Shaw; D. Lamb

2001-01-01

220

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

USGS Publications Warehouse

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

Hostetler, S. W.

1991-01-01

221

Reservoir Evaporation Prediction Using Data Driven Techniques  

Microsoft Academic Search

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

R. Arunkumar; V. Jothiprakash

2013-01-01

222

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

Microsoft Academic Search

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

Øistein Høstmark; Sigurd Teigland

2009-01-01

223

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

224

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

PubMed Central

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

Salvucci, Guido D.; Gentine, Pierre

2013-01-01

225

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

Microsoft Academic Search

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

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

2009-01-01

226

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

PubMed

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

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

2012-12-11

227

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

NASA Astrophysics Data System (ADS)

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

Rafkin, Scot C. R.

2012-10-01

228

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

SciTech Connect

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

Poirier, M.R.

2000-09-21

229

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

230

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

Microsoft Academic Search

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

Gyoko Nagayama; Masako Kawagoe; Atsushi Tokunaga; Takaharu Tsuruta

2010-01-01

231

TEMPORAL VARIATIONS IN MODEL-DERIVED EVAPORATION IN THE NORTHEASTERN AND MIDWESTERN U.S  

Microsoft Academic Search

Since Peterson et al. (1995) identified a con- sistent downward trend in pan evaporation at sites in the United States and former Soviet Union, there has been considerable debate in the literature as to the relationship between trends in pan evaporation and actual evaporation. In the United States, the trend in pan evaporation was reported as -3.2 standard anoma- ly

Arthur T. DeGaetano; Keith L. Eggleston

232

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

Microsoft Academic Search

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

Wanguang Li

1995-01-01

233

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

PubMed

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

Fujii, Mikiya; Takatsuka, Kazuo

2007-02-06

234

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

PubMed

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

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

2006-10-01

235

Evaporation of an iodine sphere: hindered diffusion and Langmuir's conjecture.  

PubMed

Here we examine Langmuir's conjecture (1918) regarding hindered diffusion in the context of the computation of a diffusion coefficient for iodine in air from experimental results. Using an expression that he derived for diffusion from a small sphere in an infinite nonabsorbing medium, Langmuir calculated a diffusion coefficient based on the measured (Morse, 1910) rate of mass loss from a small sphere of iodine sitting on the flat pan of a microbalance. He obtained a diffusion coefficient of 0.053 cm(2)/s under the experimental conditions but noted that due to the pan of the microbalance, diffusion in all directions was hindered, and that the actual diffusion coefficient was more likely closer to 0.07 cm(2)/s. To examine how the pan of the microbalance might have hindered the evaporation, we have considered a two-sphere model in which one sphere is evaporating. The other sphere is purely absorbing and comparatively large compared to the evaporating sphere so a flat surface can be approximated. For generality in future applications with arbitrary geometries, we solve the diffusion equation in the volume surrounding the spheres using Green's function to obtain the normalized evaporation rate of the sphere and compare it to that of an evaporating sphere surrounded by a large volume of air. In doing so, we have reinterpreted the experimental data, accounting for the hindered diffusion, obtaining a diffusion coefficient of 0.072 cm(2)/s, which supports Langmuir's conjecture. PMID:19891456

Smith, Zebadiah M; Loyalka, Sudarshan K

2010-01-19

236

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

NASA Astrophysics Data System (ADS)

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

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

1985-01-01

237

Characteristics of Evaporation Rate of Water in Superheated Steam and Air  

NASA Astrophysics Data System (ADS)

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

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

238

Evaporative instabilities  

NASA Astrophysics Data System (ADS)

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

Ozen, O.

239

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

Microsoft Academic Search

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

Mahboubeh Fazaeli; Ghazale Hojjatpanah; Zahra Emam-Djomeh

240

Fuzzy logic model approaches to daily pan evaporation estimation in western Turkey \\/ Estimation de l’évaporation journalière du bac dans l’Ouest de la Turquie par des modèles à base de logique floue  

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 Keskin; Özlem Terzi; Dilek Taylan

2004-01-01

241

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

Microsoft Academic Search

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

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

2009-01-01

242

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

Microsoft Academic Search

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

G. Myburg; F. D. Auret

1992-01-01

243

Evaporation changes over the contiguous United States and the former USSR: A reassessment  

NASA Astrophysics Data System (ADS)

Observed decreases in pan evaporation over most of the United States and the former USSR during the post-WWII period, if interpreted as a decrease in actual evaporation, are at odds with increases in temperature and precipitation over many regions of these two countries. Using parallel observations of actual and pan evaporation at six Russian, one Latvian, and one U.S. experimental sites, we recalibrate trends in pan evaporation to make them more representative of actual evaporation changes. After applying this transformation, pan evaporation time series over southern Russia and most of the United States reveal an increasing trend in actual evaporation during the past forty years.

Golubev, Valentin S.; Lawrimore, Jay H.; Groisman, Pavel Ya.; Speranskaya, Nina A.; Zhuravin, Sergey A.; Menne, Matthew J.; Peterson, Thomas C.; Malone, Robert W.

244

Actual and Apparent Evapotranspiration in the Environment: A Study Toward the Resolution of the Evaporation Paradox  

Microsoft Academic Search

Over the past 50 years evaporation from pans has been shown to be decreasing. Until recently, pan evaporation was widely accepted to be proportional to landscape evapotranspiration. This decrease stands out against data that show an increase in global precipitation. This paradox can be explained using Bouchet's complimentary relationship. At the root of the paradox is that evaporation pans measure

D. M. Kahler; W. Brutsaert

2005-01-01

245

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

SciTech Connect

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

Hsu, Irving; Mills, Bernice E.

2010-08-01

246

Soil Evaporation  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

247

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

248

On Maximum Evaporation Rates of Liquid Droplets in Rocket Motors 1  

Microsoft Academic Search

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

S. S. PENNER

1953-01-01

249

Mechanics of PAN Nanofibers  

NASA Astrophysics Data System (ADS)

Novel and scalable fabrication methods, such as electrospinning and pulsed laser deposition, provide low-cost polymeric nanofibers for structural applications. However, there is insufficient knowledge about the structural and mechanical behavior of polymeric nanostructures, which, in turn, limits their potential as enabling materials. The knowledge void in the systematic mechanical characterization of polymeric nanofibers is addressed in this chapter with focus on the room-temperature temporal and scale-dependent mechanical response of polyacry-lonitrile (PAN) nanofibers. Their molecular structure and deformation processes are intimately related to their fabrication conditions, and this chapter describes the first effort in literature to establish fabrication—structure-properties interrelations. The nanoscale experiments presented here demonstrate strong diameter dependence of the elastic modulus and tensile strength of PAN nanofibers for a variety of electro-spinning conditions, while for particular fabrication conditions, the applied strain rate is shown to result in non-monotonic mechanical behaviors and very unusual deformation profiles during cold drawing.

Naraghi, Mohammad; Chasiotis, Ioannis

250

Instrument for Measuring Evaporation.  

National Technical Information Service (NTIS)

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

A. H. Schooley

1965-01-01

251

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

PubMed

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

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

2010-11-18

252

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

NASA Astrophysics Data System (ADS)

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

Komatsu, Hikaru

2004-11-01

253

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

254

PANs in the atmosphere  

SciTech Connect

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 in the atmosphere are discussed and calculations made of the production of RCO radicals from precursor alkanes, alkenes and aromatic hydrocarbons present in the atmosphere. Lifetimes of PANs are estimated, and the effects of transport on the composition of PANs has been evaluated.

Altshuller, A.P.

1993-09-01

255

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

National Technical Information Service (NTIS)

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

A. B. Rosencrance E. E. Brueggemann

1993-01-01

256

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

Microsoft Academic Search

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

Hassan E. S. Fath

1997-01-01

257

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

Microsoft Academic Search

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

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

258

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

259

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 ...

260

14. RW Meyer Sugar Mill: 18761889. Sorghum Pan. Manufactured by ...  

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

14. RW Meyer Sugar Mill: 1876-1889. Sorghum Pan. Manufactured by John Nott & Co., Honolulu, Hawaii, 1878. View: In the sorghum pan, heat was applied to the cane juice to clarify it, evaporate its water content, and concentrate the sugar crystals. The pan was set on a slope so that the juice would move through the compartments by gravity. The hand-lever sluice valves in the partition walls between the compartments permitted the sugar boiler to regulate the movement of batches of cane juice flowing through the pan. The metal fins projecting from the bottom of the pan imparted a circuitous route to the juice as it flowed through the pan--this made it flow over a much greater heated surface. The fins also supplemented the pan's heating surface by ... - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

261

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

Microsoft Academic Search

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

C. Armenta-Deu

1997-01-01

262

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

Microsoft Academic Search

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

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

2004-01-01

263

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

Microsoft Academic Search

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

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

2007-01-01

264

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

Microsoft Academic Search

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

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

2008-01-01

265

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

Microsoft Academic Search

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

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

2008-01-01

266

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

267

Evaporating apparatus  

SciTech Connect

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

Sumitomo, H.

1988-06-28

268

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

NASA Astrophysics Data System (ADS)

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

Jodat, Amin; Moghiman, Mohammad; Anbarsooz, Morteza

2012-08-01

269

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

270

Comparison of energy-budget evaporation losses from two morphometrically different Florida seepage lakes  

USGS Publications Warehouse

Evaporation was computed by the energy-budget method for two north Florida lakes with similar surface areas but different depths, for the period May 1989 to December 1990. Lake Barco, in north-central Florida, is shallow, with an average depth of 3 m; Lake Five-O, in the Florida panhandle, is considerably deeper, with an average depth of 9.5 m. As a result, the thermal regime and seasonal evaporation rates of the lakes are different. Evaporation from the shallower lake was higher than that from the deeper lake in the winter and spring. In the late summer and autumn, however, the situation is reversed. Evaporation from the shallow lake is directly related to the amount of incoming shortwave radiation because of its limited ability to store energy. The lag in evaporation at the deeper lake is a function of the greater amount of heat that it seasonally stores and releases. The difference in annual evaporation between Lake Barco (151 cm year-1) and Lake Five-O (128 cm year-1) is related to differences in regional climatic conditions between the two sites. Additionally, higher than normal evaporation rates at the two lakes are probably related to drought conditions experienced in north Florida during 1990, which resulted in higher temperatures and more incoming radiation. Monthly evaporation at Lake Barco could usually be estimated within 10% of the energy-budget evaporation using a constant pan coefficient. This lake may be representative of other shallow lakes that do not store considerable heat. Monthly evaporation at Lake Five-O, however, could not be estimated accurately by using an annual pan coefficient because of the large seasonal influence of change in stored heat. Monthly mass-transfer evaporation compared well with energy-budget evaporation at Lake Barco, but did not compare well at Lake Five-O. These errors may also be associated with changes in heat storage. Thus, the thermal regime of the lake must be considered to estimate accurately the seasonal evaporation rates from a deep lake. ?? 1994.

Sacks, L. A.; Lee, T. M.; Radell, M. J.

1994-01-01

271

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

272

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

273

Potash recovery from process and waste brines by solar evaporation and flotation. Report of Investigations/1984  

SciTech Connect

The Bureau of Mines investigated energy-efficient methods for recovering potash values from process and waste brines. Laboratory pan evaporation of four chloride brines produced crude salts containing predominantly sylvite, halite, and carnallite. Six sulfate-chloride brines produced crude salts containing primarily schoenite, kainite, leonite, sylvite, carnallite, and halite. An economic evaluation suggested a rate of return of 3 pct for a new facility and 9 pct if the process is adapted to fit an existing plant.

Foot, D.G.; Huiatt, J.L.; Froisland, L.J.

1984-01-01

274

Metallization: Evaporation  

NSDL National Science Digital Library

This website includes an animation depicting an overview of the metallization evaporation processes. Objective: Identify the process of evaporation. This simulation is from Module 061 of the Process & Equipment II Cluster of the MATEC Module Library (MML). You can find this animation under the section "Process & Equipment II." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtml

2012-10-05

275

EFFECTS OF ADDITION RATE AND ACID MATRIX ON THE DESTRUCTION OF AMMONIUM BY THE SEMI-CONTINUOUS ADDITION OF SODIUM NITRITE DURING EVAPORATION  

SciTech Connect

The destruction of ammonium by the semi-continuous addition of sodium nitrite during acidic evaporation can be achieved with a wide range of waste compositions. The efficiency of nitrite utilization for ammonium destruction was observed to vary from less than 20% to 60% depending on operating conditions. The effects of nitric acid concentration and nitrite addition rate are dominant factors that affect the efficiency of nitrite utilization for ammonium destruction. Reducing the acid concentration by performing acid recovery via steam stripping prior to performing nitrite destruction of ammonium will require more nitrite due to the low destruction efficiency. The scale-up of the baseline rate nitrite addition rate from the 100 mL to the 1600 gallon batch size has significant uncertainty and poses the risk of lower efficiency at the plant scale. Experience with plant scale processing will improve confidence in the application of nitrite destruction of ammonium to different waste streams.

Kyser, E

2007-08-27

276

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

277

The pipes of pan.  

PubMed

The pipes of pan is the crowning achievement of Pablo Picasso's neoclassical period of the 1920s. This monumental canvas depicts a mythological Mediterranean scene in which two sculpted classical giants stare out, seemingly across the centuries, toward a distant and lost Arcadia. Picasso was influenced by Greco-Roman art during his travels in Italy, and his neoclassical works typically portray massive, immobile, and pensive figures. Pan and his pipes are taken directly from Greek mythological lore by Picasso and placed directly into 20th century art. He frequently turned to various mythological figures throughout his metamorphosing periods. The Pipes of Pan was also influenced by the painter's infatuation with the beautiful American expatriate Sara Murphy, and the finished masterpiece represents a revision of a previously conceived neoclassical work. The Pipes of Pan now hangs in the Musee Picasso in Paris. PMID:15574231

Chalif, David J

2004-12-01

278

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

USGS Publications Warehouse

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

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

1977-01-01

279

Evaporating droplets  

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

280

3. RW Meyer Sugar Mill: 18761889. Sorghum pan and boiling ...  

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

3. RW Meyer Sugar Mill: 1876-1889. Sorghum pan and boiling range flue. Manufactured by John Nott & Co., Honolulu, Hawaii, 1878. View: South side of sorghum pan and boiling range flue. In the sorghum pan heat was applied to the cane juice to clarify it, evaporate its water content, and concentrate the sugar crystals. Hot gasses moved through the flue underneath the entire copper bottom of the sorghum pan from the furnace (east) end to the smokestack (west) end of the boiling range. The sorghum pan sides are of redwood. The flue is built of fire-brick, masonry, and portland cement. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

281

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

Microsoft Academic Search

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

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

282

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

283

Spin coating with slow evaporation  

Microsoft Academic Search

The spin coating of polymer solutions is discussed, with emphasis on the nature of the evaporation boundary condition. A dimensional analysis reveals that the appropriate condition is a constant small evaporation rate, which is determined by the mass transfer in the adjacent atmosphere. An error in previous work [Phys. Fluids 31, 2786 (1988)] is brought to light, and it is

C. J. Lawrence

1990-01-01

284

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

285

A femtogram resolution mass sensor platform based on SOI electrostatically driven resonant cantilever. Part II: sensor calibration and glycerine evaporation rate measurement.  

PubMed

This paper presents mass measurements of glycerine beads performed by means of laterally resonant micro-cantilevers. The transducer architecture is based on a resonant cantilever electrostatically coupled by two parallel placed electrodes. Previous to glycerine measurements, a calibration of the mass sensor has been performed by measuring a standard mass based on latex spheres. From these measurements, a value of the mass responsivity is deduced. In addition, a study of the transducer phase noise has been carried out in order to determine the minimum detectable mass. Mass measurements experiments have been performed by detecting the change on the resonance frequency of the on-plane cantilever resonant mode, produced by locally deposited mass. Additionally, the mass losses detected on the calibrated transducer after glycerine drop deposition allowed determining its evaporation rate. PMID:16677762

Teva, J; Abadal, G; Torres, F; Verd, J; Pérez-Murano, F; Barniol, N

2006-04-18

286

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

287

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

288

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

NASA Astrophysics Data System (ADS)

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 clear picture of worldwide changes in evaporative demand over the last 30 to 50 years. We are also starting to gain a picture of how the observed changes in pan evaporation are related to changes in radiation, humidity and wind, as well as with changes in actual evapotranspiration. In this paper we attempt to reconcile the observed trends in pan evaporation observations with (1) generic expectations for evaporative demand in a warmer world, (2) GCM model output and (3) oceanic observations of changing evaporation and rainfall.

Roderick, M. L.; Farquhar, G. D.

2007-12-01

289

Substate and evaporation rate dependent orientation and crystalline organization of sexithiophene films vacuum deposited onto Au and HOPG  

NASA Astrophysics Data System (ADS)

The orientation and the crystalline organization of the films depend largely on the nature of the substrate and the deposition rate. The substrate effect is related to its interactions with the oligomers and also to the molecular mobility at the surface. It depends also largely on the deposition rate. L'orientation et l'organisation structurale des films de sexithiophène évaporés sous vide sont fortement liées à la nature du substrat (Au, HOPG) et à la vitesse de dépôt. L'effet du substrat est lié aux interactions avec les oligomères ainsi qu'à la mobilité de ces derniers sur la surface. Cet effet dépend largement de la vitesse d'évaporation.

El Ardhaoui, M.; Lang, P.; Garnier, F.; Roger, J. P.

1998-06-01

290

Molecular Distillation of Palm Oil Distillates: Evaporation Rates, Relative Volatility, and Distribution Coefficients of Tocotrienols and other Minor Components  

Microsoft Academic Search

The effects of feed flow rate and temperature of distillation on extraction of minor components from PFAD were studied in terms of concentration, distribution coefficient and relative volatilities. The order of volatilities for tocotrienols, based on the distribution coefficients, was desmethyl tocotrienols (??T3)>??tocotrienols (??T3)>??tocotrienols (??T3). The separation of tocotrienols from FFA approached maximum values only at low temperatures and fell

John Shi; Luidy Rodríguez Posada; Yukio Kakuda; Sophia Jun Xue

2007-01-01

291

Prevention against Oxidation of Mn Evaporant during Reactive Evaporation Process  

NASA Astrophysics Data System (ADS)

Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, during which its deposition rate deteriorates with increasing deposition run. So it is difficult to maintain the stoichiometry of films from run to run. To prevent deteriorations, a quartz ampoule has been installed at the bottom of the Mn crucible, which isolated successfully the Mn evaporant from incoming oxygen atoms. It improved the reproducibility of film composition because of stabilizing of the deposition rate. The performance of quartz ampoule was compared with that of Mo separator and stainless steel (SUS) cell.

Isai, Masaaki; Fujiyasu, Hiroshi

2001-11-01

292

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 Taï National Park, Côte 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

2012-02-13

293

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

Microsoft Academic Search

The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an

D Tamburello; R Richard Dimenna; S Si Lee

2009-01-01

294

15. RW Meyer Sugar Mill: 18761889. Sorghum pan and boiling ...  

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

15. RW Meyer Sugar Mill: 1876-1889. Sorghum pan and boiling range flue. Manufactured by John Nott & Co., Honolulu, Hawaii, 1878. View: North side of sorghum pan and boiling range flue, with furnace-end in background. In the sorghum pan heat was applied to the cane juice to clarify it, evaporate its water content, and concentrate the sugar crystals. Hot gasses moved through the flue underneath the entire copper bottom of the sorghum pan from the furnace end (in background) to the smokestack end (in foreground). After the hot cane juice moved through the separate compartments until it reached the final compartment (now missing two sides) where it was drawn out from the copper lip in the corner. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

295

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

296

Indications of increasing land surface evaporation during the second half of the 20th century  

Microsoft Academic Search

It is generally agreed that the evaporation from pans has been decreasing for the past half century over many regions of the Earth. However, the significance of this negative trend, as regards terrestrial evaporation, is still somewhat controversial, and its implications for the global hydrologic cycle remain unclear. The controversy stems from the alternative views that these evaporative changes resulted,

Wilfried Brutsaert

2006-01-01

297

A Graphical Representation of the Evaporation Solution Space and the Complementary Relationship  

NASA Astrophysics Data System (ADS)

The Complementary Relationship (CR) between regional evapotranspiration E and potential or pan evaporation Ep can be written as Ep-E0 = b(E0-E), where E0 is the evaporation rate if the entire regional surface was wet. The CR corresponds to the idea that reduced evaporation due to drying of the land surface results in increased sensible heat fluxes and an increased potential for evaporation. Recent (2009) contributions to the theory behind the CR by Pettijohn and Salvucci and by Szilagyi and Jozsa led to a much clearer grasp of the physics behind the CR by examining the role of two-dimensional heat and vapor transport. Recent papers such as those mentioned above have questioned the traditional idea that b=1, while at the same time raising questions about the proper representations of E0 and Ep. As a result, the conceptual simplicity of the original CR models by Bouchet, Morton, and Brutsaert and Stricker is no longer obvious. The goal of this work was to provide a visual representation of local evaporation as defined by the Penman-Monteith equation, and to illustrate different CR models by highlighting those parts of the Penman-Monteith evaporation solution-space that are also part of a CR model solution-space. Specifically, EF is found for a wide range of values of rs/ra and EA/Qn, where EF=E/Qn, Qn is the available energy, rs is the stomatal resistance, ra is the aerodynamic resistance, and EA is the drying power of the air. These results are used to create a 3-dimensional EF surface as a function of rs/ra and EA/Qn. Representations of several CR models based on different values of b, E0 and Ep are represented as curves drawn on the 3-D EF surface. Variations in models include those for which b=1 or b=5; for which E0 is defined with the Priestley Taylor ?=1 or ?=1.26; and for which Ep is found from Penman's equation or from simulated pan evaporation. Differences in the curves for different versions of the CR are noted. One conclusion is that, while b tends to be in the range of 3 to 6 for Ep determined from pan evaporation, a close reading of the paper by Pettijohn and Salvucci suggests it is much closer to 1 for Ep from the Penman equation. This helps to reconcile the generally good results that have been found in the literature using the Advection-Aridity approach, with the more recent reports of strong asymmetry in the CR (that is, of values of b much larger than 1).

Crago, R. D.

2011-12-01

298

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

Microsoft Academic Search

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

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

1998-01-01

299

Counterion evaporation  

SciTech Connect

We study the adsorption behavior of a highly charged rodlike polyelectrolyte approaching an oppositely charged planar wall in an unbounded electrolyte solution. The grand potential, the entropy, and the total number of screening particles are calculated as functions of the rod-wall distance, using input parameters that are typical of a DNA-molecule and charged lipid bilayers. It is found that counterions which are bound to the polyelectrolyte at infinite rod-wall distances will be released, or {open_quotes}evaporated,{close_quotes} as the DNA molecule moves closer to the charged wall. This effect can be regarded as the opposite of the ion-condensation process. The transition of ions from the system of screening ions into the reservoir of bulk ions can lead to an increase of the enthalpy. This gain of enthalpy for the whole system manifests itself as an attractive contribution to the effective interaction between the wall and the polyelectrolyte.

Fleck, C.; von Grunberg, H. H.

2001-06-01

300

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

301

Laboratory Prototype Flash Evaporator.  

National Technical Information Service (NTIS)

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

J. L. Gaddis

1972-01-01

302

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

303

PanSNPdb: The Pan-Asian SNP Genotyping Database  

PubMed Central

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.

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

2011-01-01

304

Analysis of pump oil and alkanes evaporation  

Microsoft Academic Search

There are many products, including hard drives, which require trace amounts, on the order of several mg, of lubricants for proper operation. The following study investigated the evaporation rates of pump oil and several alkanes, which have a wide range of applications, using a thermogravimetric machine. Both static and dynamic temperature tests were conducted. The rate of evaporation of the

Nathaniel A Waldstein

2008-01-01

305

Pan paniscus and human evolution  

Microsoft Academic Search

Detailed comparisons of the postcranium, cranium, and den- tition of Pan paniscus, Pan troglodytes, and Homo reveal that except for slight differences in fore- and hindlimb proportions and the morphology of the shoulder, the postcranium of the two species of Pun are allometrically scaled variants of the same animal and one does not resemble Homo more than the other. Nor

Henry M. McHenry; Robert S. Corruccini

1981-01-01

306

Snap-on oil pan  

Microsoft Academic Search

A clip-on type oil pan is described for attachment to the bottom edge of the skirt of an engine block. The edge includes a horizontal ledge extending circumferentially around and outwardly from the skirt. The pan is formed adjacent its upper portion with a trough shaped portion with vertical side walls adapted to receive the ledge for attachment of the

A. H. Berger; R. E. Diehl

1987-01-01

307

Pan 13th Annual Forum.  

National Technical Information Service (NTIS)

This conference grant supported the Parkinson's Action Network (PAN)'s 13th Annual Research and Education Forum for Parkinson's patients, their families/caretakers and advocates held February 11 to 13, 2007 at the Washington Plaza Hotel, Washington, DC. T...

A. Comstock Rick

2007-01-01

308

High Temperature Pan Granulation of Fertilizer Materials. Compendium on Low- and Non-Waste Technology.  

National Technical Information Service (NTIS)

The company uses pan granulation of an essentially water-free melt at high temperature. High temperature pan granulation gives a high particle growth rate with a low recycle ratio compared to other granulation techniques. Energy requirements are favorable...

1981-01-01

309

Tear film dynamics with evaporation and osmolarity  

NASA Astrophysics Data System (ADS)

We consider a model problem for the evaporation and breakup up of tear film. The model includes the effects of surface tension, Marangoni stresses, insoluble surfactant transport, evaporation, osmolarity transport, osmosis and wetting of corneal surface. Evaporation is made dependent on surface concentration in order to mimic the lipid layer of the tear film when there is a single fluid layer in the model. In many cases for a single layer, the Marangoni effect seems to eliminate a localized area of increased evaporation due to reduced surfactant concentration. In this model the osmolarity in the tear film increases because of average evaporation rate rather than by a locally increased evaporation rate. If time permits, the effect of having a second fluid layer, representing the lipid layer, will be explored as well.

Siddique, Javed; Braun, Richard

2011-11-01

310

Some critical transitions in pool flash evaporation  

Microsoft Academic Search

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

Noam Lior

1997-01-01

311

The Relation of External Evaporative Conditions to the Drying of Soils  

Microsoft Academic Search

Evaporation from laboratory soil columns was studied as a function of potential evaporative conditions. The length of time a given evaporation rate could be maintained by the soil was in good agreement with an approximate solution of the isothermal equation for unsatu- rated flow. During the falling-rate period of drying, the evaporation rate was found to approach very nearly a

W. R. Gardner; D. I. Hillel

1962-01-01

312

Estimation of banana ( Musa sp.) plant transpiration using a standard 20 cm pan in a greenhouse  

Microsoft Academic Search

An experiment was carried out in a naturally ventilated greenhouse to study the relationship between banana (Musa sp.) plant transpiration (Tr) measured with load cells, reference crop evapotranspiration (ETo) calculated with five widely used models (i.e. the Priestley-Taylor, FAO radiation, Hargreaves, FAO Penman and FAO Penman-Monteith\\u000a models) and pan evaporation (Epan) measured with a standard Chinese 20 cm pan. Microclimatic conditions

Hai-Jun Liu; Shabtai Cohen; Josef Tanny; Jorge Hugo Lemcoff; GuanHua Huang

2008-01-01

313

Evaporation of water from agitated freezing slurries at low pressure  

Microsoft Academic Search

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

L. C. Dickey

1996-01-01

314

The CEPHEUS Pan-Asian survey: high low-density lipoprotein cholesterol goal attainment rate among hypercholesterolaemic patients undergoing lipid-lowering treatment in a Hong Kong regional centre.  

PubMed

OBJECTIVES. To evaluate attainment of low-density lipoprotein cholesterol goals among hypercholesterolaemic patients undergoing lipid-lowering drug treatment in Hong Kong and to identify potential determinants of treatment outcomes. DESIGN. Cross-sectional observational study. SETTING. A single site in Hong Kong, as part of the CEPHEUS Pan-Asian survey. PATIENTS. Subjects with hypercholesterolaemia aged 18 years or above, who had been on lipid-lowering drug treatment for at least 3 months with no dose adjustment for at least 6 weeks. RESULTS. A total of 561 such patients (mean age, 65.3; standard deviation, 9.7 years) were evaluated. Most had major cardiovascular risk factors; 534 (95.2%) of 561 patients had coronary heart disease and 534 (95.4%) of 560 patients had low-density lipoprotein cholesterol goals set at lower than 70 mg/dL. In all, 465 (82.9%) patients attained their respective low-density lipoprotein cholesterol goals. Among 75 patients who had coronary heart disease or equivalent risk, and multiple risk factors with a 10-year coronary heart disease risk of over 20%, 62 (82.7%) attained their respective low-density lipoprotein cholesterol goals. Significant predictors of low-density lipoprotein cholesterol goal attainment included the patient's baseline lipid profile (total cholesterol and low-density lipoprotein cholesterol levels), blood pressure, and drugs (statin/non-statin) used for treatment. CONCLUSIONS. Hypercholesterolaemic patients undergoing lipid-lowering drug treatment in the present Hong Kong study were able to achieve a very high attainment rate for the low-density lipoprotein cholesterol goal, despite the fact that most of them had major cardiovascular risk factors. PMID:23018067

Chan, Raymond H W; Chan, P H; Chan, Kelvin K W; Lam, Simon C C; Hai, Jo Jo; Wong, Michael K L; Tam, Frankie C C; Lam, Linda; Chan, Carmen W S; Lam, Y M; Siu, David C W; Tse, H F; Lee, Stephen W L

2012-10-01

315

Evaporative Emission Model (EVAP 3.0) (for Microcomputers).  

National Technical Information Service (NTIS)

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 p...

1993-01-01

316

Worldwide Evaporation Maps.  

National Technical Information Service (NTIS)

World maps are given showing evaporation for the year and for each separate month. The method used for calculating the evaporation was developed at the Main Geophysical Observatory. The calculations were made for 1460 points located on all continents exce...

L. I. Zubenok

1968-01-01

317

Measuring liquid evaporation from micromachined wells  

Microsoft Academic Search

The evaporation process of liquids from sub-nanoliter wells is studied using both optical microscopy and electrical impedance measurement utilizing integrated electrodes. The wells are manufactured on silicon wafers using conventional photolithography and etching techniques. The volumes of the wells vary from 15 to 540 pl. The evaporation rate of glycol from wells of various sizes is determined to vary from

Kari T Hjelt; Richard van den Doel; Wijnand Lubking; Michiel J Vellekoop

2000-01-01

318

Evaporation of Lennard-Jones fluids  

Microsoft Academic Search

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

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

2011-01-01

319

Disposal of Brine by Solar Evaporation.  

National Technical Information Service (NTIS)

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

C. G. Keyes N. N. Gunaji

1968-01-01

320

Preciptation, Evaporation, and Transpiration Activity  

NSDL National Science Digital Library

The students must use crayons or colored pencils to create maps of global precipitation and evaporation rates. One worksheet is provided to each group of students. Then a representative from each group explains their map to the rest of the class, and the instructor shows a similar map from NOAA or NASA.

Townsend-Small, Amy

321

Evaporator Cleaning Studies  

SciTech Connect

Operation of the 242-16H High Level Waste Evaporator proves crucial to liquid waste management in the H-Area Tank Farm. Recent operational history of the Evaporator showed significant solid formation in secondary lines and in the evaporator pot. Additional samples remain necessary to ensure material identity in the evaporator pot. Analysis of these future samples will provide actinide partitioning information and dissolution characteristics of the solid material from the pot to ensure safe chemical cleaning.

Wilmarth, W.R.

1999-04-15

322

Comparison of different methods for estimating soil surface evaporation in a bare field  

NASA Astrophysics Data System (ADS)

In this paper, three methods for estimating soil evaporation in a bare field were evaluated: evaporation ratio method ( k ratio), complementary relationship and bulk equation. Micro-lysimeters were used to measure the actual evaporation for validation of the three methods. For the k ratio method, pan evaporation was used as the reference evaporation instead of the value obtained from the Penman-Monteith equation. This result is important for areas where meteorological data are unavailable. The results showed that, for daytime evaporation, the k ratio and bulk equation produced a good fit with the observation data, while the complementary relationship generated a larger deviation from the measured data. We recommend that the k ratio method and bulk equation could be used to calculate daytime soil evaporation with high accuracy when soil water content and pan evaporation data or meteorological data are available, while the complementary relationship could be used for a rough estimation when pan evaporation is available. All the methods could be applied to calculate cumulative evaporation.

Yan, Haofang; Zhang, Chuan; Oue, Hiroki; Sugimoto, Hideki

2012-11-01

323

Evaporative cooling in insects  

Microsoft Academic Search

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

Henry D. Prange

1996-01-01

324

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

Microsoft Academic Search

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

Donald C. Walker

1963-01-01

325

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

Microsoft Academic Search

Measurements of pan evaporation were made during the summers of 1957 and 1958 on an ice station drifting between 80° and 86°N. 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

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

2010-01-01

326

Evaporation Data in Texas, Compilation Report, January 1907-December 1970.  

National Technical Information Service (NTIS)

This report presents a complete compilation of all available historical pan-evaporation data which have been obtained in Texas, spanning a 64-year period. The data was gathered from 114 stations which have been in operation in Texas during some part of th...

J. P. Dougherty

1975-01-01

327

Evaporation Atlas for the Contiguous 48 United States.  

National Technical Information Service (NTIS)

Maps are presented showing the areal distribution in the contiguous 48 states of evaporation (1) observed from Class A pans from May through October, (2) estimated for a free water surface (FWS) with negligible heat storage from May through October, and (...

R. K. Farnsworth E. S. Thompson E. L. Peck

1982-01-01

328

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

329

PanAmAir.org  

NSDL National Science Digital Library

On January 16, 1928, seven passengers riding aboard a Fokker-7 inaugurated Pan American World Airlines passenger services as they flew from Key West to Havana. Over the next six decades, PanAm would grow and prosper, as it created an extensive system of routes that took early jet-setters all around the world. While the airline did experience a rebirth in the mid-1990s, its demise was hastened after the tragedy onboard Flight 103 over Lockerbie, Scotland in 1988.Created by Beth Cozzi-Stewart, this site provides interested parties with access to a great deal of colorful material on the history of the company. Some of the offerings include a detailed history spanning PanAm's years, a chronology of the aircraft they utilized, and information about the various accidents that befell the company. Perhaps the most enjoyable part of the site is the "Multimedia" section, which includes the PanAm jingles "Just Say Hello to PanAm" and "We Fly the Way the World Wants to Fly".

Cozzi-Stewart, Beth

2004-01-01

330

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

SciTech Connect

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

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

1986-09-01

331

Evaluation and generalization of radiation?based methods for calculating evaporation  

Microsoft Academic Search

Abstract: 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

V. P. Singh

2000-01-01

332

Evaporation and potential evapotranspiration in India under conditions of recent and future climate change  

Microsoft Academic Search

Long-term changes in evaporation and potential evapotranspiration can have profound implications for hydrologic processes as well as for agricultural crop performance. This paper analyses evaporation time series data for different stations in India, and for the country as a whole, for different seasons on both a short-term (15 years) and long-term (32 years) basis for pan evaporation and on a

N. Chattopadhyay; M. Hulme

1997-01-01

333

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

334

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2012 CFR

... 4 2012-10-01 2012-10-01 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...

2012-10-01

335

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2011 CFR

... 4 2011-10-01 2011-10-01 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...

2011-10-01

336

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

337

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

338

Effects of hydrophobic layers on evaporation from porous media  

NASA Astrophysics Data System (ADS)

Early stages of evaporation from initially-saturated porous media are marked by relatively high and constant evaporation rate (``stage 1'') supplied by capillary flow from the receding drying front to evaporating surface. At a characteristic front depth defined by pore size distribution, gravity exceeds capillary-drive and interrupts liquid flow. Subsequently, evaporation falls to rates supported by vapor diffusion (``stage 2''). We investigated the role of thin hydrophobic layers on liquid phase continuity and on evaporative losses. Results confirm interruption of capillary flow by hydrophobic layers and overall reduction in evaporation mass loss. Persistence of capillary flow to the bottom of hydrophobic layer was evident by accumulation of dye tracer indicating formation of vaporization plane. Dye was not deposited on hydrophobic surfaces due to contact line configuration that promote evaporation away from pore walls. Evaporation flux across the hydrophobic layer was purely diffusive and proportional to diffusion length to the surface.

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

2008-10-01

339

Liquid Hydrocarbon Evaporation Under Simulated Titan Conditions  

NASA Astrophysics Data System (ADS)

Ethane and methane-ethane mixtures are condensed and monitored in our Titan simulation chamber, under Titan surface conditions. Results on the evaporation rate of these liquids that are most probably the main components of the lakes are presented.

Luspay-Kuti, A.; Wasiak, F. C.; Chevrier, V. F.; Welivitiya, W. D. D. P.; Roe, L. A.; Cornet, T.; Magar, S. S.

2012-03-01

340

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

341

Evaporation of Sessile Droplets of Liquid on Solid Substrates  

NASA Astrophysics Data System (ADS)

Evaporation of sessile droplets of liquid on solid substrates is considered here. Different parameters and processes influencing the evaporation rate are discussed. Cases of complete wetting and partial wetting with contact angle hysteresis are described mathematically. The influence of Kelvin's and kinetic effects and subsequent deviation from diffusion-limited evaporation is shown by means of computer simulations.

Semenov, S.; Starov, V. M.; Velarde, M. G.; Rubio, R. G.

342

Mechanistic study of the evaporation of liquids from porous microparticles  

Microsoft Academic Search

The objective of this study is to investigate the evaporation of volatile liquids from individual microparticles composed of an aggregate of primary porous particles. The evaporation of octyl alcohol from microparticles containing porous silica was measured using single particle electrodynamic levitation. Liquid evaporation rates were determined from changes in the particle- levitation electric field intensities. A class of Syloid silicas

Glenn O. Rubel

1995-01-01

343

On the evaporation of ammonium sulfate solution  

PubMed Central

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

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

2009-01-01

344

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

345

A multimodel simulation of pan-Arctic hydrology  

NASA Astrophysics Data System (ADS)

We compare the performance of five land surface models (Chameleon Surface Model (CHASM), Noah, Community Land Model (CLM), Variable Infiltration Capacity Model (VIC), European Centre for Medium Range Weather Forecasts (ECMWF)), in the simulation of hydrological processes across the terrestrial Arctic drainage system for the period 1980-2001. The models represent a wide range of model physics, particularly with respect to high-latitude processes, and are forced with surface meteorology derived from the ERA-40 reanalysis. Models offer great potential for enlightenment regarding large-scale hydrology in this poorly observed region; thus our objective is to assess the ability of the models to capture various aspects of pan-Arctic hydrology as well as identify those features that contain the largest uncertainty. Results reveal up to a 30% difference in annual partitioning of precipitation between evaporation and runoff with major Arctic watersheds such as the Lena. Capturing the correct base flow of the large rivers is a consistent problem. The model hydrographs are often out of phase, peaking too early in comparison to observations. However, allowing for a large uptake in soil moisture as well as moisture movement during frozen periods alleviates this discrepancy. A negative correlation exists between models and observations for annual runoff time series over the Yenesi basin, apparently mostly because of inconsistencies in the input data. Compared to station data, all models produce similar errors in snow water equivalent; yet they differ widely in their snow regimes in terms of snowfall quantity, estimated snow depths, and most importantly, sublimation rates. Additionally, model albedo is consistently higher than observations in the presence of snow. No single model is the best or worst performing when compared to a range of observations.

Slater, A. G.; Bohn, T. J.; McCreight, J. L.; Serreze, M. C.; Lettenmaier, D. P.

2007-12-01

346

Ground moisture evaporation in crawl spaces  

Microsoft Academic Search

Air change rate, humidity and temperature were monitored in a naturally and a mechanically ventilated crawl space of the test building, in order to determine the ground moisture evaporation rate and the mass transfer coefficient. The average value of the moisture evaporation with uncovered ground was 3.6–5.7 g\\/h m2, corresponding to the mass transfer coefficient 0.0012–0.0018 m\\/s. The mass transfer coefficient determined

Jarek Kurnitski

2001-01-01

347

Roll formed pan solar module  

Microsoft Academic Search

A solar module comprising a solar cell string laminated between layers of pottant material and a transparent superstrate and a steel substrate. The steel substrate is roll formed to provide stiffening flanges on its edges while simultaneously forming a pan-shaped structure to hold other portions of the laminate in position during the laminating process. An improved terminal provides high voltage

T. L. Jester; W. R. Bottenberg; C. F. Gay; J. W. Yerkes

1984-01-01

348

Hard-pan soils - Management  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard pans, hard layers, or compacted horizons, either surface or subsurface, are universal problems that limit crop production. Hard layers can be caused by traffic or soil genetic properties that result in horizons with high density or cemented soil particles; these horizons have elevated penetrati...

349

Peroxyacetyl nitrate (PAN): historical perspective.  

National Technical Information Service (NTIS)

This paper is an overview of the history of PAN's discovery and its connection to plant damage observed in the South Coast Air Basin of southern California. The focus will be the work done by pioneers in this research area, particularly the long-path infr...

J. S. Gaffney N. A. Marley

2000-01-01

350

78 FR 23101 - Pan American Day and Pan American Week, 2013  

Federal Register 2010, 2011, 2012, 2013

...8957--Pan American Day and Pan American Week, 2013 Presidential Documents Federal Register...2013 Pan American Day and Pan American Week, 2013 By the President of the United States...prosperity. As we celebrate those ties this week, we recognize the Pan American...

2013-04-17

351

Water evaporation on highly viscoelastic polymer surfaces.  

PubMed

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

Pu, Gang; Severtson, Steven J

2012-06-19

352

Vapor compression evaporator concentrates, recovers alcohol  

SciTech Connect

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

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

1982-11-01

353

Sodium Evaporation into a Forced Argon Flow, (I) Measurements of Evaporation under Condition of Fog Formation  

Microsoft Academic Search

Measurements were made on the rate of evaporation from a rectangular-shaped free surface of liquid sodium into argon flow. Tests were carried out at various levels of sodium temperature, of argon velocity and of argon temperature, under conditions where fog formation could be expected.To gain information on the enhancement of evaporation occasioned by fog formation, a supplementary experiment was performed

Toshiaki KUMADA; Fumio KASAHARA; Ryoji ISHIGURO

1976-01-01

354

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

355

Evaporation of water droplets containing carbon nanotubes  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

356

A New Technique Keeping off the Mn Evaporant from Oxygen Atmosphere during Reactive Evaporation Process  

NASA Astrophysics Data System (ADS)

Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, which deteriorates it’s deposition rate with increasing deposition run. It is also difficult to maintain the stoichiometry of films from run to run. This paper shows a new technique which keeps off the Mn evaporant from oxygen atmosphere during the reactive evaporation process. To achieve it a stainless steel cell has been installed in the bottom of the Mn crucible, which can successfully isolate Mn evaporant from incoming oxygen atoms. It improves the reproducibility of film composition because of stabilizing of the deposition rate.

Isai, Masaaki; Shimada, Takeyoshi; Matsui, Takaaki; Fujiyasu, Hiroshi

2001-08-01

357

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 ...

358

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 D’yachkova Norm Phillips Jay Onysko Rene Shumak Norah Smith Nancy Wadden Measuring Radiologist Skill Measuring Radiologist

359

Evaporative cooling of trapped atoms  

SciTech Connect

This report discusses the following topics on evaporative cooling of trapped atoms: Theoretical models for evaporative cooling; the role of collisions for real atoms; experimental techniques and summary of evaporative cooling experiments. 166 refs., 6 figs., 3 tabs.

Ketterle, W.; Van Druten, N.J. [Massachusetts Inst. of Technology, Cambridge, MA (United States)

1996-12-31

360

Evaporative Cooling of Trapped Atoms  

Microsoft Academic Search

This report discusses the following topics on evaporative cooling of trapped atoms: Theoretical models for evaporative cooling; the role of collisions for real atoms; experimental techniques and summary of evaporative cooling experiments. 166 refs., 6 figs., 3 tabs.

Wolfgang Ketterle; N. J. Van Druten

1996-01-01

361

Analysis of evaporation in laser welding  

Microsoft Academic Search

The evaporation process in CO2 laser welding was analyzed experimentally on the basis of evaporation and soot deposition rates, light scattering and plasma behavior. Heavier shielding gas results in more soot deposition by carrying the condensed particles to the work surface. At power density, 2-3 x 10(exp 5) W\\/sq cm), which is just below the critical value for deep penetration

Isamu Miyamoto

1995-01-01

362

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

363

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

364

Evaporation, Condensation, and Precipitation  

NSDL National Science Digital Library

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

Brown, Miss

2009-10-21

365

Maintenance strategy for a salt gradient solar pond coupled with an evaporation pond  

Microsoft Academic Search

In a previous study, the authors presented a simple mathematical model for predicting the ratio of the evaporation pond area to that of a salt gradient solar pond area. The evaporation pond idea provides a very attractive method of salt recycling by evaporation, especially in areas of high evaporation and low rates of rain as it is the case for

K. R. Agha; S. M. Abughres; A. M. Ramadan

2004-01-01

366

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

Microsoft Academic Search

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

S. M. Bower; J. R. Saylor

2009-01-01

367

Formation of Titan's Lakes by Episodic Dissolution and Precipitation of a Surface Layer Under Semi-Arid Conditions: Comparison with the Pans and Calcretes of Etosha (Namibia)  

NASA Astrophysics Data System (ADS)

Radar images from the Cassini spacecraft reveal closed, smooth and flat depressions above northern and southern latitudes of 60° on Titan, Saturn’s largest moon. These depressions have been interpreted as lakes of liquid hydro-carbons and dissolved nitrogen, resting on the icy crust that covers this moon. The depressions include large (over 100,000 square kilometers) seas with dendritic or poorly defined contours, small (1-10 km wide) circular steep-sided depressions, and medium-sized (20-50 km wide) depressions, the contours of which are composed of adjacent circular segments. Some depressions are completely filled with radar-dark material, while others are partially filled and some are empty. Most of these depressions lie in flat plains. By comparison with a terrestrial analogue located in the Etosha Basin (Namibia), we introduce here a dissolution-precipitation model for the formation of these lakes at the expense of a superficial soluble layer. The Etosha Basin is a flat sedimentary basin located at the western border of the Kalahari desert. The climate is semi-arid, with an average annual precipitation rate of 400 mm/yr and an average annual potential evaporation rate of 2200 mm/yr. Sediments in the basin include clays and silts; they are covered by a layer of soluble calcrete a few meters in thickness. The calcrete has formed by precipitation, in the subsurface, of calcium carbonate dissolved in groundwater. Precipitation of calcium carbonate from groundwater is due to the average annual dominance of groundwater evaporation over precipitation. The calcrete layer is dotted with dozens of so-called pans: these are closed, steep-sided, flat and smooth depressions, 1 to 200 km wide and a few meters deep. Relict boulders of calcrete rest on the silty, clayey and evaporitic floors of the pans and provide evidence that the pans grow by radial regressive dissolution of the calcrete layer. By comparison with the development of pans at the expense of the calcrete layer of Etosha, we infer that the small and medium-sized lakes of Titan grow by regressive radial dissolution, during flooding episodes associated with rainstorms, of a superficial soluble layer. The formation of this layer can be explained, as for the superficial calcrete layer of Namibia, by precipitation at or near the topographic surface of non-volatile materials, during evapo-ration after rainstorms of liquids accumulated in the ground.

Bourgeois, O.; Lopez, T.; Le Mouélic, S.; Fleurant, C.; Tobie, G.; Cornet, T.

2009-12-01

368

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

369

Flash Evaporator Systems Test.  

National Technical Information Service (NTIS)

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/o...

J. B. Dietz

1976-01-01

370

Mixed feed evaporator  

DOEpatents

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

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

1982-01-01

371

Potential evaporation trends over land between 1983-2008: driven by radiative or turbulent fluxes?  

NASA Astrophysics Data System (ADS)

We model the Penman potential evaporation (PE) over all land areas of the globe for the 25-year period 1983-2008, relying on radiation transfer models (RTMs) for the shortwave and longwave fluxes. Penman's PE is determined by two factors: available energy for evaporation and ground to atmosphere vapour transfer. Input to the PE model and RTMs comprises satellite cloud and aerosol data, as well as data from reanalyses. PE is closely linked to pan evaporation, whose trends have sparked controversy in the community, since the factors responsible for the observed pan evaporation trends are not determined with consensus. Our particular interest is the temporal evolution of PE, and the provided insight to the observed trends of pan evaporation. We examine the interannual trends of PE and various related physical quantities, such as net solar flux, net longwave flux, water vapour saturation deficit and wind speed. Our findings are the following: Global warming has led to a larger water vapour saturation deficit. Global dimming/brightening cycles in the last 25 years slightly increased the available energy for evaporation. PE trends seem to follow closely the trends of energy availability and not the trends of the atmospheric capability for vapour transfer, almost everywhere on the globe, with trends in the Northern hemisphere significantly larger than in the Southern. These results support the hypothesis that secular changes in the radiation fluxes, and not vapour transfer considerations, are responsible for potential evaporation trends.

Matsoukas, C.; Benas, N.; Hatzianastassiou, N.; Pavlakis, K. G.; Kanakidou, M.; Vardavas, I.

2011-04-01

372

Protein antifouling mechanisms of PAN UF membranes incorporating PAN g-PEO additive  

Microsoft Academic Search

The antifouling mechanism of a novel polyacrylonitrile (PAN) ultrafiltration (UF) membrane incorporating the amphiphilic comb copolymer additive, polyacrylonitrile-graft-polyethylene oxide (PAN-g-PEO), has been investigated using a laboratory-scale cross-flow test unit and atomic force microscopy (AFM). In fouling tests with a bovine serum albumin (BSA) solution, PAN UF membranes incorporating 20% PAN-g-PEO possessed excellent antifouling characteristics, whereas a commercial PAN UF membrane

Seoktae Kang; Ayse Asatekin; Anne M. Mayes; Menachem Elimelech

2007-01-01

373

Evaporation of petroleum products from contaminated soils  

SciTech Connect

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 diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions.

Kang, S.H. [Kwangwoon Univ., Seoul (Korea, Republic of). Dept. of Environmental Engineering; Oulman, C.S. [Iowa State Univ., Ames, IA (United States)

1996-05-01

374

A fundamental cause of an enormous amount of evaporation during rainfall by canopy interception: Evaporative force proposed by Makarieva and Gorshkov  

Microsoft Academic Search

An enormous amount of evaporation from forest canopy is observed during rainfall as canopy interception. The evaporation rate often exceeds well over 10 mm h-1 that requires latent heat of five times solar constant (6814 W m-2 at 20°C). On top of that, evaporation rate is proportional to the rainfall intensity. Namely, once the saturation of canopy is reached, the

Shigeki Murakami

2010-01-01

375

Measured Performance of Falling-Jet Flash Evaporators.  

National Technical Information Service (NTIS)

The rates of heat transfer and approach to thermal equilibrium of flash evaporators operating at pressures of 2 to 4 kPa are investigated. Experiments were performed to measure heat and mass transfer rates from falling jet evaporators operating in the tem...

H. J. Green D. A. Olson D. Bharathan D. H. Johnson

1981-01-01

376

EVAPORATION FROM SHALLOW WATER TABLE THROUGH LAYERED SOIL PROFILES  

Microsoft Academic Search

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

C. P. Kumar

1999-01-01

377

Evaporation and Surface Structure of Liquids  

Microsoft Academic Search

The condensation coefficient (C.C.) of a liquid is defined as the ratio of the observed rate of evaporation under given conditions to the 'expected' rate calculated from the known saturation vapour pressure, for the same conditions. Values of the C.C. less than 1 have been reported in the past, but the accuracy of the experiments has been criticized on various

G. Wyllie

1949-01-01

378

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; Vereš, 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

379

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

380

Evaporation-induced cavitation in nanofluidic channels  

PubMed Central

Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitation in the nanoscale is generally believed to be energetically unfavorable and has never been experimentally demonstrated. Here we report evaporation-induced cavitation in water-filled hydrophilic nanochannels under enormous negative pressures up to -7 MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro- and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale.

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

2012-01-01

381

How do drops evaporate?  

NASA Astrophysics Data System (ADS)

The problem of evaporating drops with non-pinned contact line, although seemingly trivial, so far lacks satisfactory theoretical description. In particular, there has been much discussion regarding appropriate evaporative mass flux model. We make an attempt to resolve this issue by comparing our experimental data with the results of several mathematical models for evaporating drops. After describing experimental procedure, we propose several models for mass flux and develop a governing equation for evolution of drop's thickness. Two-dimensional numerical results are then compared to the experimental results, and the most appropriate mass flux model is identified. Finally, we propose the governing equation for the full 3D system and present some new numerical results related to curious phenomena, where so-called ``octopus-shaped'' instabilities appear ahead of the contact line of volatile dropsootnotetextY. Gotkis, I. Ivanov, N. Murisic, L. Kondic, Phys. Rev. Lett. 97, 186101 (2006)..

Murisic, Nebojsa; Kondic, Lou

2007-11-01

382

Evaporatively driven morphological instability.  

PubMed

Simple observations of evaporating solutions reveal a complex hierarchy of spatiotemporal instabilities. We analyze one such instability suggested by the qualitative observations of Du and Stone and find that it is driven by a variant of the classical morphological instability in alloy solidification. In the latter case a moving solid-liquid interface is accompanied by a solutally enriched boundary layer that is thermodynamically metastable due to constitutional supercooling. Here, we consider the evaporation of an impure film adjacent to a solid composed of the nonvolatile species. In this case, constitutional supercooling within the film is created by evaporation at the solution-vapor interface and this drives the corrugation of the solid-solution interface across the thickness of the film. The principal points of this simple theoretical study are to suggest an instability mechanism that is likely operative across a broad range of technological and natural systems and to focus future quantitative experimental searches. PMID:17677459

Style, Robert W; Wettlaufer, J S

2007-07-16

383

Experimental and theoretical investigations on interfacial temperature jumps during evaporation  

Microsoft Academic Search

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

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

2007-01-01

384

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

385

Dry deposition of peroxyacetyl nitrate (PAN): Determination of its deposition velocity at night from measurements of the atmospheric PAN and 222Radon concentration gradient  

NASA Astrophysics Data System (ADS)

During the field campaign POPCORN (Photooxidant Formation by Plant Emitted Compounds and OH-Radicals in North-Eastern Germany) in August 1994 we measured the nighttime deposition velocities of PAN above a corn field. These are the first absolute measurements of PAN deposition velocities in the field. The deposition velocities were derived using a novel method, which uses measurements of the gradients of PAN and 222Rn and of the emission rates of 222Rn from the soil. A unique data set of about 250 field measurements of the PAN deposition velocity at night was thus obtained. The deposition velocity at night proved to be highly variable with an average of 0.54 cm/s and a standard deviation of 0.94 cm/s. Recent presumptions by Shepson et al. [1992] that the PAN deposition velocity is strongly reduced with increasing relative humidity could not be confirmed by our measurements.

Schrimpf, Wolfram; Lienaerts, Karlheinz; Müller, Klaus Peter; Rudolph, Jochen; Neubert, Rolf; Schüßler, Wolfram; Levin, Ingeborg

386

Trends in Pan Evaporation and Application of the Complimentary Relationship of Evaporation in the Great Basin, USA  

Microsoft Academic Search

Evaluating available water resources in the Great Basin is an increasing topic of discussion by several local, State, and Federal government agencies due to proposals for water importation into areas of rapid population growth. In estimating a water budget for a particular flow system in the Great Basin, groundwater evapotranspiration (ET) from phreatophyte vegetation is often the most important as

J. L. Huntington; T. Caldwell; R. Naranjo; S. Burak; S. Tyler

2007-01-01

387

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

388

Microscale Evaporation Heat Transfer  

Microsoft Academic Search

In this work, microscale evaporation heat transfer and capillary phenomena for ultra thin liquid film area are presented. The interface shapes of curved liquid film in rectangular minichannel and in vicinity of liquid-vapor-solid contact line are determined by a numerical solution of simplified conduction through liquid layer. The data of numerical calculation of local heat transfer in rectangular channel and

V. V. Kuznetsov; S. A. Safonov

389

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

Microsoft Academic Search

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

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

2008-01-01

390

WAIV - Wind aided intensified evaporation for brine volume reduction and generating mineral byproducts  

Microsoft Academic Search

In this study bench pilot WAIV units (? 1 m evaporation area loaded on 0.17 m footprint) were operated on two different desalination brines (RO and ED) as well as on a mineral brine concentrate under arid conditions of the Negev Highlands. The evaporation rate with the WAIV unit on these feeds often gave evaporation rates per footprint that were

Lilach Katzir; Y. Volkmann; N. Daltrophe; E. Korngold; R. Mesalem; Y. Oren; Jack Gilron

2010-01-01

391

Design methodology for a salt gradient solar pond coupled with an evaporation pond  

Microsoft Academic Search

This paper presents the results of a simple mathematical model for predicting the ratio of the evaporation pond (EP) area to that of a Salt Gradient Solar Pond (SGSP) area. The EP idea provides a very attractive method of salt recycling by evaporation, especially in areas of high rates of evaporation and low rates of rain as it is the

K. R. Agha; S. M. Abughres; A. M. Ramadan

2002-01-01

392

Distributed virtual network interfaces to support intra-PAN and PAN-to-infrastructure connectivity  

Microsoft Academic Search

In emerging personal area networks (PANs), consisting of heterogeneous devices and nodes, dynamic intra-PAN and PAN-to-infrastructure connectivity should be achieved transparently to end users and applications. This paper proposes a distributed virtual network interface (DVNI) solution for PAN device discovery, seamless handover and routing. DVNI is an extension of the VNI concept designed for seamless vertical handover in the case

Kaouthar Sethom; Mehdi Sabeur; Badii Jouaber; Hossam Afifi; Djamal Zeghlache

2005-01-01

393

Mexicantown Whole Issues Allergy Alert On Undeclared Pecans In Pan Nuez And Undeclared Milk In Magdalena, Pan De Maiz, YoyoPan Nuez, And Tacos De Pan Danes  

NASA Website

PAN DE MAIZ, YOYO and TACOS DE PAN DANES manufactured between 6/27/2010 and 12/28/2010, because they contain undeclared milk. People who have an allergy or severe sensitivity to milk run the risk of serious or life-threatening allergic reaction if ...

394

Granulation of Urea in a Pan Granulator  

Microsoft Academic Search

Urea granulation is favored over prilling due to the problems associated with prilling. Tumbling agglomeration technique is employed in pan granulator. Product with wide size range can be produced by playing with only few parameters like binders (water and urea solution), ratio of binders, rpm of pan, granulation time and angle of inclination. Urea granulation is studied at laboratory scale

U. Irshad; M. N. Sharif; R. U. Khan; Z. H. Rizvi

395

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

396

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 0.64±0.49 and 0.57±0.46ppb, 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., 1h) 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

2013-07-06

397

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

398

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

2013-04-16

399

Evaporation rate of PTFE liquid marbles  

Microsoft Academic Search

Liquid marbles are hydrophilic liquid drops encapsulated with a hydrophobic powder. They behave as micro-reservoirs of liquids able to move rapidly without any leakage and are promising candidates to be applied in genetic analysis where 2D microfluidics and lab-on-a-chip methods are used. The manipulation of liquid marbles using gravitational, electrostatic and magnetic fields were recently investigated. In this work, we

A. Tosun; H. Y. Erbil

2009-01-01

400

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

401

NWCF Evaporator Tank System 2001 Offgas Emissions Inventory  

Microsoft Academic Search

An offgas emissions inventory and liquid stream characterization of the Idaho New Waste Calcining Facility (NWCF) Evaporator Tank System (ETS), formerly known as the High Level Liquid Waste Evaporator (HLLWE), has been completed. The emissions rates of volatile and semi-volatile organic compounds, multiple metals, particulate, and hydrochloric acid were measured in accordance with an approved Quality Assurance Project Plan (QAPjP)

R. D. Boardman; K. M. Lamb; L. A. Matejka; J. A. Nenni

2002-01-01

402

MICROLAYER FORMATION, EVAPORATION AND BUBBLE GROWTH IN NUCLEATE BOILING  

Microsoft Academic Search

A numerical study of microlayer formation and evaporation is reported in which computer programs developed in order to predict the isothermal (initial) and the instantaneous microlayer thicknesses as well as the time varying mass evaporated from the microlayer for any specified bubble growth rate are presented. The results of these programs show that the isothermal microlayer thickness (delta)(,0)(r) is of

HASSAN EL-BANNA SAAD FATH

1981-01-01

403

Microlayer Formation, Evaporation and Bubble Growth in Nucleate Boiling  

Microsoft Academic Search

A numerical study of microlayer formation and evaporation is reported in which computer programs developed in order to predict the isothermal (initial) and the instantaneous microlayer thicknesses as well as the time varying mass evaporated from the microlayer for any specified bubble growth rate are presented. The results of these programs show that the isothermal microlayer thickness ??(r) is of

Hassan El-Banna Saad Fath

1981-01-01

404

Evaporation in Equilibrium, in Vacuum, and in Hydrogen Gas.  

National Technical Information Service (NTIS)

Evaporation experiments were conducted for SiO2 in three different conditions: in equilibrium, in vacuum, and in hydrogen gas. Evaporation rate in vacuum is about two orders of magnitude smaller than that in equilibrium, which is consistent with previous ...

H. Nagahara

1993-01-01

405

Gas entrainment in an evaporating spray jet  

Microsoft Academic Search

Gas entrainment induced by a spray jet can be significantly affected by the spray evaporation rate. In this study, we have directly measured the air entrainment induced by a liquid nitrogen spray jet into an unbounded and stagnant room air. It is realized that the air entrainment is proportional to the axial gradient of oxygen mass flow in a pure

Muhammad Mushahid Rafique Qureshi; Chao Zhu

2006-01-01

406

Direct Observation of Evaporation from Quiescent Water  

Microsoft Academic Search

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

Karol J. Mysels

1959-01-01

407

Evaporative estimation using data fusion  

Microsoft Academic Search

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

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

2008-01-01

408

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 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. 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

2010-07-02

409

Evaporative cooling of magnetically trapped atomic molybdenum  

SciTech Connect

We have magnetically trapped and evaporatively cooled atomic molybdenum. Using a cryogenic helium buffer gas, 2x10{sup 10} molybdenum atoms are loaded into a magnetic trap at an initial temperature of 500 mK. The molybdenum atoms undergo two-body decay with a measured inelastic rate constant of g{sub in}=(1.2{+-}0.6)x10{sup -12} cm{sup 3} s{sup -1} for the initial conditions after loading. The molybdenum atoms are cooled by adiabatic expansion and forced evaporation to 200 mK.

Hancox, Cindy I.; Hummon, Matthew T.; Nguyen, Scott V.; Doyle, John M. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2005-03-01

410

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

411

PANNOTATOR: an automated tool for annotation of pan-genomes.  

PubMed

Due to next-generation sequence technologies, sequencing of bacterial genomes is no longer one of the main bottlenecks in bacterial research and the number of new genomes deposited in public databases continues to increase at an accelerating rate. Among these new genomes, several belong to the same species and were generated for pan-genomic studies. A pan-genomic study allows investigation of strain phenotypic differences based on genotypic differences. Along with a need for good assembly quality, it is also fundamental to guarantee good functional genome annotation of the different strains. In order to ensure quality and standards for functional genome annotation among different strains, we developed and made available PANNOTATOR (http://bnet.egr.vcu.edu/iioab/agenote.php), a web-based automated pipeline for the annotation of closely related and well-suited genomes for pan-genome studies, aiming at reducing the manual work to generate reports and corrections of various genome strains. PANNOTATOR achieved 98 and 76% of correctness for gene name and function, respectively, as result of an annotation transfer, with a similarity cut-off of 70%, compared with a gold standard annotation for the same species. These results surpassed the RAST and BASys softwares by 41 and 21% and 66 and 17% for gene name and function annotation, respectively, when there were reliable genome annotations of closely related species. PANNOTATOR provides fast and reliable pan-genome annotation; thereby allowing us to maintain the research focus on the main genotype differences between strains. PMID:24065654

Santos, A R; Barbosa, E; Fiaux, K; Zurita-Turk, M; Chaitankar, V; Kamapantula, B; Abdelzaher, A; Ghosh, P; Tiwari, S; Barve, N; Jain, N; Barh, D; Silva, A; Miyoshi, A; Azevedo, V

2013-08-16

412

Potash recovery from process and waste brines by solar evaporation and flotation  

SciTech Connect

The Bureau of Mines investigated energy-efficient methods for recovering potash values from process and waste brines. Laboratory pan evaporation of four chloride brines produced crude salts containing predominantly sylvite, halite, and carnallite. Six sulfate-chloride brines produced crude salts containing primarily schoenite, kainite, leonite, sylvite, carnallite, and halite. Potash grades ranged from 7.2 to 22.2% K/sub 2/O, and recoveries from 84 to 99%. Sylvite flotation from chloride evaporites, with amine collector, recovered 90 to 97% of the potash in a concentrate containing 54.3 to 60.3% K/sub 2/O. Fatty acid flotation of the high-sulfate evaporite recovered 78% of the sulfate minerals in a 27.8%-K/sub 2/O concentrate. Flotation of the chloride minerals with amine collector recovered 80% of the potash in a 59.7%-K/sub 2/O concentrate. Solar evaporation of 10,000 gal of brine recovered 99% of the potash in a crude evaporite containing 24.5% schoenite and 20 pct sylvite. Continuous flotation in a 100-lb/h process research unit recovered over 95% of the potash in schoenite and sylvite concentrates containing 28.0 and 62.3% K/sub 2/O, respectively. An economic evaluation suggested a rate of return of 3% for a new facility and 9% if the process is adapted to fit an existing plant.

Foot, D.G. Jr.; Huiatt, J.L.; Froisland, L.J.

1984-01-01

413

Analysis of evaporation in laser welding  

NASA Astrophysics Data System (ADS)

The evaporation process in CO2 laser welding was analyzed experimentally on the basis of evaporation and soot deposition rates, light scattering and plasma behavior. Heavier shielding gas results in more soot deposition by carrying the condensed particles to the work surface. At power density, 2-3 x 10(exp 5) W/sq cm), which is just below the critical value for deep penetration welding, the soot deposition becomes heaviest with accompanying violent fluctuation of the light emission of the plasma. A hypothetical mechanism of the soot deposition is proposed; at 2-3 x 10(exp 5) W/sq cm, the molten pool surface is hemispherically depressed by the recoil force of evaporation, and acts like a concave mirror to refocus the reflected laser beam within the plasma plume to heat it up. The adiabatic expansion of the plasma caused by the molten pool motion plays an important role to condense the vapor into the soot.

Miyamoto, Isamu

1995-04-01

414

The Upper Tropospheric Budget of PAN  

NASA Astrophysics Data System (ADS)

Peroxyacetyl nitrate (PAN) is a key species in tropospheric chemistry. It acts as a reservoir for NOx, allowing it to be transported over large distances in the cold upper troposphere (UT). When UT air masses descend and warm PAN breaks down and the NOx released can lead to O3 production. PAN therefore plays an important role in the long-range transport of pollution to remote clean areas. Recently, the first global measurements of upper tropospheric PAN and acetone have been retrieved from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on board ENVISAT. MIPAS is a Fourier transform spectrometer which detects limb emission spectra in the middle and upper atmosphere for the retrieval of atmospheric trace gases. Here, we present these new observations (along with other available species such as ozone and nitric acid) and compare them to simulated PAN from the TOMCAT 3-D chemical transport model (CTM). We will investigate the PAN budget in the upper troposphere through the combined use of satellite and aircraft observations together with model simulations of PAN, its precursors and degradation products.

Richards, N. A. D.; Chipperfield, M. P.; Arnold, S. R.; Moore, D. P.; Remedios, J. J.

2009-04-01

415

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

416

Spent-fuel pool thermal hydraulics: The evaporation question  

SciTech Connect

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

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

1996-12-31

417

Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest  

NASA Astrophysics Data System (ADS)

During the Biosphere Effects on AeRosols and Photochemistry EXperiment 2007 (BEARPEX-2007), we observed eddy covariance (EC) fluxes of speciated acyl peroxy nitrates (APNs), including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN) and peroxymethacryloyl nitrate (MPAN), above a Ponderosa pine forest in the western Sierra Nevada. All APN fluxes are net downward during the day, with a median midday PAN exchange velocity of -0.3 cm s-1; nighttime storage-corrected APN EC fluxes are smaller than daytime fluxes but still downward. Analysis with a standard resistance model shows that loss of PAN to the canopy is not controlled by turbulent or molecular diffusion. Stomatal uptake can account for 25 to 50% of the observed downward PAN flux. Vertical gradients in the PAN thermal decomposition (TD) rate explain a similar fraction of the flux, suggesting that a significant portion of the PAN flux into the forest results from chemical processes in the canopy. The remaining "unidentified" portion of the net PAN flux (~15%) is ascribed to deposition or reactive uptake on non-stomatal surfaces (e.g. leaf cuticles or soil). Shifts in temperature, moisture and ecosystem activity during the summer - fall transition alter the relative contribution of stomatal uptake, non-stomatal uptake and thermochemical gradients to the net PAN flux. Daytime PAN and MPAN exchange velocities are a factor of 3 smaller than those of PPN during the first two weeks of the measurement period, consistent with strong intra-canopy chemical production of PAN and MPAN during this period. Depositional loss of APNs can be 3-21% of the gross gas-phase TD loss depending on temperature. As a source of nitrogen to the biosphere, PAN deposition represents approximately 4-19% of that due to dry deposition of nitric acid at this site.

Wolfe, G. M.; Thornton, J. A.; Yatavelli, R. L. N.; McKay, M.; Goldstein, A. H.; Lafranchi, B.; Min, K.-E.; Cohen, R. C.

2009-01-01

418

Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN, and MPAN) above a Ponderosa pine forest  

NASA Astrophysics Data System (ADS)

During the Biosphere Effects on AeRosols and Photochemistry EXperiment 2007 (BEARPEX-2007), we observed eddy covariance (EC) fluxes of speciated acyl peroxy nitrates (APNs), including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN) and peroxymethacryloyl nitrate (MPAN), above a Ponderosa pine forest in the western Sierra Nevada. All APN fluxes are net downward during the day, with a median midday PAN exchange velocity of -0.3 cm s-1; nighttime storage-corrected APN EC fluxes are smaller than daytime fluxes but still downward. Analysis with a standard resistance model shows that loss of PAN to the canopy is not controlled by turbulent or molecular diffusion. Stomatal uptake contributes to 25 50% of the observed downward PAN flux. Vertical gradients in the PAN thermal decomposition (TD) rate explain a similar fraction of the flux, suggesting that a significant portion of the PAN flux into the forest results from chemical processes in the canopy. The remaining "unidentified" portion of the net PAN flux (~15%) is ascribed to deposition or reactive uptake on non-stomatal surfaces (e.g. leaf cuticles or soil). Shifts in temperature, moisture and ecosystem activity during the summer fall transition alter the relative contribution of stomatal uptake, non-stomatal uptake and thermochemical gradients to the net PAN flux. Daytime PAN and MPAN exchange velocities are a factor of 3 smaller than those of PPN during the first two weeks of the measurement period, consistent with strong intra-canopy chemical production of PAN and MPAN during this period. The depositional loss of APNs can be 3 21% of the gross gas-phase TD loss depending on temperature. As a source of nitrogen to the biosphere, PAN deposition is approximately 4 19% of that due to dry deposition of nitric acid at this site.

Wolfe, G. M.; Yatavelli, R. L. N.; Thornton, J. A.; McKay, M.; Goldstein, A. H.; Lafranchi, B.; Min, K.-E.; Cohen, R. C.

2008-09-01

419

Kepler Planets: A Tale of Evaporation  

NASA Astrophysics Data System (ADS)

Inspired by the Kepler mission's planet discoveries, we consider the thermal contraction of planets close to their parent star, under the influence of evaporation. The mass-loss rates are based on hydrodynamic models of evaporation that include both X-ray and EUV irradiation. We find that only low mass planets with hydrogen envelopes are significantly affected by evaporation, with evaporation being able to remove massive hydrogen envelopes inward of ~0.1 AU for Neptune-mass objects, while evaporation is negligible for Jupiter-mass objects. Moreover, most of the evaporation occurs in the first 100 Myr of stars' lives when they are more chromospherically active. We construct a theoretical population of planets with varying core masses, envelope masses, orbital separations, and stellar spectral types, and compare this population with the sizes and densities measured for low-mass planets, both in the Kepler mission and from radial velocity surveys. This exercise leads us to conclude that evaporation is the driving force of evolution for close-in Kepler planets. In fact, some 50% of the Kepler planet candidates may have been significantly eroded. Evaporation explains two striking correlations observed in these objects: a lack of large radius/low density planets close to the stars and a possible bimodal distribution in planet sizes with a deficit of planets around 2 R ?. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ~0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ? and the majority of them should have core masses of a few Earth masses.

Owen, James E.; Wu, Yanqin

2013-10-01

420

Dry deposition of pan to grassland vegetation  

Microsoft Academic Search

Peroxyacetyl nitrate or PAN (CHâC(O)OONOâ) is formed in the lower troposphere via photochemical reactions involving nitrogen oxides (NOâ) and non-methane hydrocarbons (NMHCs). PAN has a lifetime in the free troposphere of about three months and is removed by photolysis or reaction with OH. Dry deposition will decrease its lifetime, although the few measurements that have been made indicate that this

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

1994-01-01

421

Cosmological lensing with Pan-STARRS  

NASA Astrophysics Data System (ADS)

With 30,000 square degrees coverage, Pan-STARRS 1 will be the largest optical survey designed to be capable of cosmological studies through weak lensing. I report on the status of the cosmological lensing programme of Pan-STARRS. Although the full power of the project will only be apparent when the survey is complete, I will review the early data and the prospects for science.

Heavens, Alan

2011-05-01

422

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 Titan’s 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

423

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

Microsoft Academic Search

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

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

1968-01-01

424

Saturation and Cooling of Air Layers by Evaporation from Falling Rain  

Microsoft Academic Search

The changes in temperature and relative humidity caused by evaporation from raindrops are computed for several cases involving three different lapse rates and two rainfall intensities. Formulae for evaporation from stationary drops are modified to include the effects of relative velocity and continuously changing air temperature. It is found that saturation, due to evaporation alone, will not be produced in

Edward J. Dolezel

1944-01-01

425

Water Evaporation and Conformational Changes from Partially Solvated Ubiquitin  

PubMed Central

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

Thirumuruganandham, Saravana Prakash; Urbassek, Herbert M.

2010-01-01

426

An evaporation model of colloidal suspension droplets  

NASA Astrophysics Data System (ADS)

Colloidal suspensions of polymers in water or other solvents are widely used in the pharmaceutical industry to coat tablets with different agents. These allow controlling the rate at which the drug is delivered, taste or physical appearance. The coating is performed by simultaneously spraying and drying the tablets with the colloidal suspension at moderately high temperatures. The spreading of the coating on the pills surface depends on the droplet Webber and Reynolds numbers, angle of impact, but more importantly on the rheological properties of the drop. We present a model for the evaporation of a colloidal suspension droplet in a hot air environment with temperatures substantially lower than the boiling temperature of the carrier fluid. As the liquid vaporizes from the surface, a compacting front advances into the droplet faster than the liquid surface regresses, forming a shell of a porous medium where the particles reach their maximum packing density. While the surface regresses, the evaporation rate is determined by both the rate at which heat is transported to the droplet surface and the rate at which liquid vapor is diffused away from it. This regime continues until the compacting front reaches the center of the droplet, at which point the evaporation rate is drastically reduced.

Sartori, Silvana; Li\\ Nán, Amable; Lasheras, Juan C.

2009-11-01

427

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

428

Utility of Penman Monteith, Priestley Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration  

Microsoft Academic Search

Actual evapotranspiration (ETa) was measured at 30-min resolution over a 19-month period (September 28, 2000 April 23, 2002) from a nonirrigated pasture site in Florida, USA, using eddy correlation methods. The relative magnitude of measured ETa (about 66% of long-term annual precipitation at the study site) indicates the importance of accurate ETa estimates for water resources planning. The time and

David M. Sumner; Jennifer M. Jacobs

2005-01-01

429

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

430

Comparison of techniques for estimating evaporation from an irrigation water storage  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

431

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

432

EVAPORATIVE COOLING AND WATER BALANCE DURING FLIGHT IN BIRDS  

Microsoft Academic Search

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

JOSE R. TORRE-BUENO

433

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

SciTech Connect

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 prospective candidate for the treatment of acidic wastes) were studied. Aqueous 1M HNO{sub 3} + 1M NaNO{sub 3}, 1M NaOH + 1M NaNO{sub 3}, and 1M NaOH were chosen as simulants of DOE acidic and alkaline wastes. In addition,radiation stability was determined indistilled water. The chemical stability of B-PAN and AMP-PAN beads was tested for a period up to one month of contact with the solution at ambient temperature. The radiation stability of the beads was checked in a radiation dose range 10{sup 3}--10{sup 6} Gy (10{sup 5}--10{sup 8} rads). In acidic solutions the stability of PAN binder was proved not to be limited by either chemical or radiation decomposition. PAN binder may thus be used for preparing composite absorbers for treatment of acid wastes from DOE facilities. The same conclusion is valid for alkaline solutions with pH up to 13. In highly alkaline solutions (concentration of NAOH higher than I M) and in the presence of NaNO{sub 3}, the stability of the tested polyacrylonitrile polymer was sufficient for applications not extending over 10 days. Cross-linking of the polymer caused by ionizing radiation was found to have a positive influence on chemical stability. This effect enables a longer period of applicability of PAN-based composite absorbers. Because of the high sorption rate achievable with PAN-based absorbers, the stability achieved is sufficient for most applications in the DOE complex. The chemical stability of binding polymer may also be further improved by testing another, more suitable type of polymer from the broad family of polyacrylonitrile polymers.

Sebesta, F.; John, J.; Motl, A.; Stamberg, K. [Czech Technical University in Prague (Czech Republic). Dept. of Nuclear Chemistry

1995-11-01

434

Henry's law constant and hydrolysis of peroxyacetyl nitrate (PAN)  

Microsoft Academic Search

The effect of temperature on the solubility of PAN and on its hydrolysis rate in near-neutral and slightly acidic water were studied in a bubble column apparatus. The results obtained are a Henry's law coefficient H=10-9.04±0.6 exp[(6513±376)\\/T] M atm-1, and a first-order hydrolysis rate constant k=106.60±1.0 exp[(-6612±662)\\/T] s-1, which was independent of pH in the range 3.2=pH=6.7. The products formed

Jost Kames; Silke Schweighoefer; Ulrich Schurath

1991-01-01

435

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.; Fröschle, M.

2012-12-01

436

Thermal effects of the substrate on water droplet evaporation  

NASA Astrophysics Data System (ADS)

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

Sobac, B.; Brutin, D.

2012-08-01

437

Thermal effects of the substrate on water droplet evaporation.  

PubMed

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

Sobac, B; Brutin, D

2012-08-20

438

75 FR 19181 - Pan American Day and Pan American Week, 2010  

Federal Register 2010, 2011, 2012, 2013

...the enduring strength of Pan American solidarity. As we mourn these...expressed at the 1936 Inter-American Conference for the Maintenance...from our ancestors a great dream. We here offer it back as...proclaim April 14, 2010, as Pan American Day and April 11 through...

2010-04-14

439

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

440

Evaporation loss of dissolved volatile substances from ice surfaces.  

PubMed

Volatile acidic solutes were used to make dilute solutions, which were frozen by various methods. The concentration of solutes and the pH of the samples were measured before and after being frozen. When the sample solution is frozen from the bottom to the top, solutes are concentrated into the unfrozen solution (i.e., the upper part of the sample) due to the freeze concentration effect. Thereafter, concentrated anions combine with protons to form acids, and the amount of acids in the unfrozen solution increase as the ice formation progresses. At the end of freezing, the acid is saturated at the ice surface, and if the formed acid is volatile, then evaporation occurs. Frozen solutions were allowed to stand below 0 degrees C, where evaporation rates were obtained in the following order: formate > acetate > propionate > n-butyrate > chloride > nitrate. Except for nitrate, evaporation rates were enough to take place in frozen water of the natural environment (e.g., ice crystal, graupel, snow crystal, and frozen droplets). The relationship between the evaporation rate of volatile acids and their physical properties demonstrate that the evaporation rates of weak acids are faster than those of strong acids, and the evaporation rates among weak acids are the same as the volatility of weak acids. PMID:18661928

Sato, Keiichi; Takenaka, Norimichi; Bandow, Hiroshi; Maeda, Yasuaki

2008-07-29

441

Polymer patterns in evaporating droplets on dissolving substrates.  

PubMed

Self-organized polymer patterns resulting from the evaporation of an organic solvent drop on a soluble layer of polymer are investigated. The patterns can be modulated by changing the rate of evaporation and also the rate of substrate dissolution controlled by its solubility. Both of these affect the contact zone motion and its instabilities, leading to spatially variable rates of substrate etching and redeposition that result from a complex interplay of several factors such as Rayleigh-Benard cells, thermocapillary flow, solutal Marangoni flow, flow due to differential evaporation, osmotic-pressure-induced flow, and contact-line pinning-depinning events. The most complex novel pattern, observed at relatively low rates of evaporation, medium solubility, and without macroscopic contact-line stick-slip, consists of a regularly undulating ring made up of a bundle of parallel spaghetti-like threads or striations and radially oriented fingerlike ridges. Increased rate of evaporation obliterates the polymer threads, producing more densely packed fingers and widely separated multiple rings due to a frequent macroscopic pinning-depinning of the contact line. Near-equilibrium conditions such as slow evaporation or increased solubility of the substrate engender a wider and less undulating single ring. PMID:15875882

Gonuguntla, Manoj; Sharma, Ashutosh

2004-04-13

442

Design of the Pan-STARRS telescopes  

NASA Astrophysics Data System (ADS)

Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System, is a project by the Institute for Astronomy, University of Hawaii, to first develop a single wide field synoptic survey telescope (Pan-STARRS-1) followed by a system of four such telescopes. It is designed to accomplish many of the science goals envisioned by the Decadal Review for the Large Synoptic Survey Telescope (LSST). The primary mission of Pan-STARRS is the detection of potentially hazardous asteroids (PHA), secondary science objectives are a (nearly) all-sky survey, a medium-deep survey, an ultra-deep survey, and studies of transients and variable objects. This paper presents the current status of the telescope system design, with emphasis on the optics.

Hodapp, K. W.; Kaiser, N.; Aussel, H.; Burgett, W.; Chambers, K. C.; Chun, M.; Dombeck, T.; Douglas, A.; Hafner, D.; Heasley, J.; Hoblitt, J.; Hude, C.; Isani, S.; Jedicke, R.; Jewitt, D.; Laux, U.; Luppino, G. A.; Lupton, R.; Maberry, M.; Magnier, E.; Mannery, E.; Monet, D.; Morgan, J.; Onaka, P.; Price, P.; Ryan, A.; Siegmund, W.; Szapudi, I.; Tonry, J.; Wainscoat, R.; Waterson, M.

2004-10-01

443

Impact of microbial transglutaminase on the staling behaviour of enzyme-supplemented pan breads  

Microsoft Academic Search

The effects of microbial transglutaminase (TGM) when added singly and in combination with amylolytic (?-amylase, NMYL) and non-amylolytic (xylanase) enzymes on the textural profile of fresh pan beads and pan breads stored for up to 20 days have been investigated in samples made with low and high extraction rate wheat flours following a sponge-dough process. White and whole-wheat enzyme-supplemented bread samples

Concepción Collar; Clara Bollaín

2005-01-01

444

Flash evaporation of chalcogenide thin films  

Microsoft Academic Search

CuInSe2 and CuGa1?xInxSe2, with x=0.25, 0.5 and 0.75, films have been grown by ‘flash’ evaporation. Films 2 ?m thick over Mo coated glass have shown columnar grains, single chalcopyrite phase and adequate optical and electrical properties as photovoltaic semiconductor. The film composition could be changed by modifying the deposition parameters, such as crucible and substrate temperatures and deposition rate. Inherent

J. M. Merino; M. León; F. Rueda; R. Diaz

2000-01-01

445

Evaporative cooling of sodium atoms  

Microsoft Academic Search

We have observed evaporative cooling of magnetically trapped sodium atoms. A novel technique, rf induced evaporation, was used to reduce the temperature by a factor of 12 and increase the phase space density by more than 2 orders of magnitude. The elastic collision cross section of cold sodium atoms in the {ital F}=1, {ital m}{sub {ital F}}=-1 hyperfine state was

Kendall B. Davis; Marc-Oliver Mewes; Michael A. Joffe; Michael R. Andrews; Wolfgang Ketterle

1995-01-01

446

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

447

Evaporators with inverted circulation loops  

Microsoft Academic Search

The evaporator operated under atmospheric pressure and under 620 mm Hg vacuum processing saturated solutions of sodium chloride (direct solubility: solubility increases at highertemperatur e) and sodium sulfate (inverse solubility: solubility decreases at higher temperature). These solutions were evaporated with crystal circulation and also with separation of crystals (clarification) by inserting a removable baffle into the separator to remove large

E. M. Kovalev; Z. F. Kostenko

1971-01-01

448

EVAPORATION OF FRUITS AND VEGETABLES  

PubMed Central

More and more the world is utilizing dried fruits and vegetables, the war having given impetus to the preparation of the latter. Here are plain statements of processes and values deduced from scientific institution investigations. Evaporation is in its infancy while sun drying is very ancient. Evaporated products are better looking but more costly. ImagesFigure 1Figure 2Figure 3

Cruess, W. V.

1921-01-01

449

An evaporation model of multicomponent solution drops  

NASA Astrophysics Data System (ADS)

Solutions of polymers are widely used in the pharmaceutical industry as tablets coatings. These allow controlling the rate at which the drug is delivered, taste or appearance. The coating is performed by spraying and drying the tablets at moderate temperatures. The wetting of the coating solution on the pill's surface depends on the droplet Webber and Re numbers, angle of impact and on the rheological properties of the droplet. We present a model for the evaporation of multicomponent solutions droplets in a hot air environment with temperatures substantially lower than the boiling temperature of the solvent. As the liquid vaporizes from the surface the fluid in the drop increases in concentration, until reaching its saturation point. After saturation, precipitation occurs uniformly within the drop. As the surface regresses, a compacting front formed by the precipitate at its maximum packing density advances into the drop, while the solute continues precipitating uniformly. This porous shell grows fast due to the double effect of surface regression and precipitation. The evaporation rate is determined by the rates at which heat is transported to the droplet surface and at which liquid vapor diffuses away from it. When the drop is fully compacted, the evaporation is drastically reduced.

Sartori, Silvana; Liñán, Amable; Lasheras, Juan C.

2010-11-01

450

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

451

Evaporation and instabilities of microscopic capillary bridges.  

PubMed

The formation and disappearance of liquid bridges between two surfaces can occur either through equilibrium or nonequilibrium processes. In the first instance, the bridge molecules are in thermodynamic equilibrium with the surrounding vapor medium. In the second, chemical potential gradients result in material transfer; mechanical instabilities, because of van der Waals force jumps on approach or a Rayleigh instability on rapid separation, may trigger irreversible film coalescence or bridge snapping. We have studied the growth and disappearance mechanisms of laterally microscopic liquid bridges of three hydrocarbon liquids in slit-like pores. At rapid slit-opening rates, the bridges rupture by means of a mechanical instability described by the Young-Laplace equation. Noncontinuum but apparently reversible behavior is observed when a bridge is held at nanoscopic surface separations H close to the thermodynamic equilibrium Kelvin length, 2r(K)costheta, where r(K) is the Kelvin radius and theta is the contact angle. During the course of slow evaporation (at H > 2r(K)costheta) and subsequent regrowth by capillary condensation (at H < 2r(K)costheta), the refractive index of the bridge may vary continuously and reversibly between that of the bulk liquid and vapor. The evaporation process becomes irreversible only at the very final stage of evaporation, when the refractive index of the fluid attains virtually that of the vapor. Measured refractive index profiles and the time-dependence of evaporating neck diameters also seem to differ from predictions based on a continuum picture of bridge evaporation far from the critical point. We discuss these findings in terms of the probable density profiles in evolving liquid bridges. PMID:12538868

Maeda, Nobuo; Israelachvili, Jacob N; Kohonen, Mika M

2003-01-21

452

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

2013-01-16

453

Evaporation from groundwater discharge playas, Estancia Basin, central New Mexico  

USGS Publications Warehouse

Bowen ratio meteorological stations have been deployed to measure rates of evaporation from groundwater discharge playas and from an adjacent vegetated bench in the Estancia Basin, in central New Mexico. The playas are remnants of late Pleistocene pluvial Lake Estancia and are discharge areas for groundwater originating as precipitation in the adjacent Manzano Mts. They also accumulate water during local precipitation events. Evaporation is calculated from measured values of net radiation, soil heat flux, atmospheric temperature, and relative humidity. Evaporation rates are strongly dependent on the presence or absence of standing water in the playas, with rates increasing more than 600% after individual rainstorms. Evaporation at site E-12, in the southeastern part of the playa Complex, measured 74 cm over a yearlong period from mid-1997 through mid-1998. This value compares favorably to earlier estimates from northern Estancia playas, but is nearly three times greater than evaporation at a similar playa in western Utah. Differences in geographical position, salt crust composition, and physical properties may explain some of the difference in evaporation rates in these two geographic regions. (C) 2000 Elsevier Science B.V.

Menking, K. M.; Anderson, R. Y.; Brunsell, N. A.; Allen, B. D.; Ellwein, A. L.; Loveland, T. A.; Hostetler, S. W.

2000-01-01

454

Vegetation Cover Decreases Evaporative Water Loss in a Wetland Ecosystem  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

455

A Flow Boiling Microchannel Evaporator Plate for Fuel Cell Thermal Management  

Microsoft Academic Search

In order to provide a high-power density thermal management system for PEM fuel cell applications, a flow boiling microchannel evaporator plate has been developed that operates in a closed loop two-phase thermosyphon. The flow is passively driven by gravity, and the flow rate initially increases with increasing evaporation rate and then decreases after reaching a peak flow rate. A microchannel

Patrick T. Garrity; James F. Klausner; Renwei Mei

2007-01-01

456

Handedness in Captive Bonobos (Pan paniscus)  

Microsoft Academic Search

Species level right-handedness is often considered to be unique to humans. Handedness is held to be interrelated to our language ability and has been used as a means of tracing the evolution of language. Here we examine handedness in 3 captive groups of bonobos (Pan paniscus) comprising 22 individuals. We found no evidence for species level handedness. Conclusions that can

Rebecca M. Harrison; Pia Nystrom

2008-01-01

457

Effect of pan on certain photosynthetic reactions  

Microsoft Academic Search

The effect of the atmospheric oxidant, peroxyacetyl nitrate (PAN) on photosynthetic phosphorylation, NADP plus reduction, and COâ fixation by chloroplasts prepared from spinach and bean plants has been studied. When this gaseous oxidant was passed through reaction mixtures in the light, inhibition of the photosynthetic reactions occurred. Inhibition in ATP and NADPH formation and the fixation of C-1402 was prevented

W. M. Jr. Dugger; J. B. Mudd; J. Koukol

1965-01-01

458

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

459

Oil shale process water evaporation. Final report.  

National Technical Information Service (NTIS)

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

V. R. Hasfurther T. Reeves

1990-01-01

460

Corrosion study of simulated evaporator components  

SciTech Connect

At the Los Alamos Plutonium Facility, ion exchange effluents and precipitation filtrates containing discardable levels of transuranic elements are concentrated using a thermosiphon evaporator before cement fixation for waste disposal. Because of changing process feed streams and scrap recovery requirements, trace amounts of free chloride ions (Cl/sup /minus//) are being introduced into the stainless steel (SS) evaporator, potentially increasing corrosion rates and thereby reducing its useful life. This study was performed to determine the effects of Cl/sup /minus// in simulated evaporator feed solutions that contain significant amounts of ferric ions (Fe/sup 3+/) in nitric acid (HNO/sub 3/). A simulated environment was produced by heating 316 SS cans that contained various tests solutions. The surface was monitored for signs of pitting or stress cracking, and vessel weight loss was measured on a daily basis to establish a rough corrosion rate. The final conclusion is that the nitric acid solution provides enough free nitrate ions (NO/sub 3//sup /minus//) to maintain minimal corrosion in a dilute ferric chloride environment. 3 refs., 5 figs., 10 tabs.

Schreiber, S.B.; Dunn, S.L.

1989-07-01

461

Pan American Health Organization: Country Health Profiles and Health  

NSDL National Science Digital Library

This site from the Pan American Health Organization (see the September 8, 1995 Scout Report) offers data and analysis on health and related sociological factors in the nations of the Americas. Users can click on the country of their choice via a map or list to access statistics on demographics, socioeconomic data, health risk factors, health care access, and mortality rates as well as an analysis of these and other data. Also available from this site is the text of Health in the Americas, a quadrennial publication that exhaustively "assesses the evolving health situation of the Americas-diseases, services, resources-at the regional and country levels" (free registration required).

462

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; Görres, Joachim; Wiescher, Michael C.

2008-06-01

463

Experimental simulations of CH4 evaporation on Titan  

NASA Astrophysics Data System (ADS)

We present the first experimental results on the evaporation of liquid CH4 under simulated Titan surface conditions similar to those observed at the Huygens landing site. An average evaporation rate of (3.1 ± 0.6) × 10-4 kg s-1 m-2 at 94 K and 1.5 bar was measured. While our results are generally higher than previous models based on energy balance, they show an excellent match with a theoretical mass transfer approach. Indeed, we find that evaporation in the Titan environmental chamber is predominantly diffusion driven and affected by the buoyancy of lighter CH4 in the heavier N2 atmosphere. After correcting for the difference in gravity of Earth and Titan, the resulting evaporation rate is (1.6 ± 0.3) × 10-4 kg s-1m-2 (or 1.13 ± 0.3 mm hr-1). Using our experimental evaporation rates, we determine that the low-latitude storm recently observed by Cassini ISS would have resulted in a maximum evaporated mass of (5.4 ± 1.2) × 1010 kg of CH4 equivalent to a 2.4 ± 0.5 m thick layer over 80 days. Based on our results, a sufficient amount of CH4 can accumulate in the otherwise arid equatorial regions to produce transient ponds and liquid flows.

Luspay-Kuti, A.; Chevrier, V. F.; Wasiak, F. C.; Roe, L. A.; Welivitiya, W. D. D. P.; Cornet, T.; Singh, S.; Rivera-Valentin, E. G.

2012-12-01

464

Superconducting tapes using ISD buffer layers produced by evaporation of MgO or reactive evaporation of magnesium  

Microsoft Academic Search

To avoid large angle grain boundaries in YBa2Cu3 O7 (YBCO) thin films, biaxially textured buffer layers were grown by inclined substrate deposition. We use MgO as buffer layer material, which can be grown at rates up to 300 mm\\/min using either e-beam evaporation of MgO or reactive thermal evaporation of magnesium. Employed substrates were Hastelloy C276 or stainless steel. Epitaxial

Ralf Metzger; Markus Bauer; Kai Numssen; Robert Semerad; Paul Berberich; Helmut Kinder

2001-01-01

465

CHEMISTRY IN EVAPORATING ICES-UNEXPLORED TERRITORY  

SciTech Connect

We suggest that three-body chemistry may occur in warm high-density gas evaporating in transient co-desorption events on interstellar ices. Using a highly idealized computational model we explore the chemical conversion from simple species of the ice to more complex species containing several heavy atoms, as a function of density and of adopted three-body rate coefficients. We predict that there is a wide range of densities and rate coefficients in which a significant chemical conversion may occur. We discuss the implications of this idea for the astrochemistry of hot cores.

Cecchi-Pestellini, Cesare [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, 09012 Capoterra (Italy); Rawlings, Jonathan M. C.; Viti, Serena; Williams, David A., E-mail: ccp@ca.astro.i, E-mail: jcr@star.ucl.ac.u, E-mail: sv@star.ucl.ac.u, E-mail: daw@star.ucl.ac.u [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2010-12-20

466

Inversion temperature for adiabatic evaporation of liquid into an air-steam mixture  

Microsoft Academic Search

This paper deals with adiabatic evaporation of various liquids into an air-steam mixture and pure superheated steam. The focus\\u000a is made on the inversion temperature, which means that the rate of liquid evaporation into an air-steam mixture (superheated\\u000a steam) becomes equal to the rate of evaporation into dry air. A simple analytical solution for finding of inversion temperature\\u000a was derived,

E. P. Volchkov; A. I. Leontiev; S. N. Makarova

2007-01-01

467

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

Microsoft Academic Search

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

K. D. Janssen; M. L. Cummings

2005-01-01

468

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

Microsoft Academic Search

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

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

1992-01-01

469

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

Microsoft Academic Search

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

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

1992-01-01

470

Thermal modeling of flow in the San Diego Aqueduct, California, and its relation to evaporation  

USGS Publications Warehouse

The thermal balance of the 26-kilometer long concrete-lined San Diego Aqueduct, a canal in southern California, was studied to determine the coefficients in a Dalton type evaporation formula. Meteorologic and hydraulic variables, as well as water temperature, were monitored continuously for a 1-year period. A thermal model was calibrated by use of data obtained during a 28-day period to determine the coefficients which best described the thermal balance of the canal. The coefficients applicable to the San Diego Aqueduct are similar to those commonly obtained from lake evaporation studies except that a greater evaporation at low windspeeds is indicated. The model was verified by use of data obtained during 113 days which did not include the calibration data. These data verified that the derived wind function realistically represents the canal evaporation. An annual evaporation of 2.08 meters was computed which is about 91 percent of the amount of water evaporated annually from nearby class A evaporation pans. (Kosco-USGS)

Jobson, Harvey E.

1980-01-01

471

Evaporative cooling: effective latent heat of evaporation in relation to evaporation distance from the skin.  

PubMed

Calculation of evaporative heat loss is essential to heat balance calculations. Despite recognition that the value for latent heat of evaporation, used in these calculations, may not always reflect the real cooling benefit to the body, only limited quantitative data on this is available, which has found little use in recent literature. In this experiment a thermal manikin, (MTNW, Seattle, WA) was used to determine the effective cooling power of moisture evaporation. The manikin measures both heat loss and mass loss independently, allowing a direct calculation of an effective latent heat of evaporation (?eff). The location of the evaporation was varied: from the skin or from the underwear or from the outerwear. Outerwear of different permeabilities was used, and different numbers of layers were used. Tests took place in 20°C, 0.5 m/s at different humidities and were performed both dry and with a wet layer, allowing the breakdown of heat loss in dry and evaporative components. For evaporation from the skin, ?eff is close to the theoretical value (2,430 J/g) but starts to drop when more clothing is worn, e.g., by 11% for underwear and permeable coverall. When evaporation is from the underwear, ?eff reduction is 28% wearing a permeable outer. When evaporation is from the outermost layer only, the reduction exceeds 62% (no base layer), increasing toward 80% with more layers between skin and wet outerwear. In semi- and impermeable outerwear, the added effect of condensation in the clothing opposes this effect. A general formula for the calculation of ?eff was developed. PMID:23329814

Havenith, George; Bröde, Peter; den Hartog, Emiel; Kuklane, Kalev; Holmer, Ingvar; Rossi, Rene M; Richards, Mark; Farnworth, Brian; Wang, Xiaoxin

2013-01-17

472

Note on Evaporation in Capillaries.  

National Technical Information Service (NTIS)

Factors are discussed which govern evaporation of liquid in small capillaries of greatly varying bore, such as might be encountered in porous media. If the escape of the vapor is relatively unobstructed, marked temperature gradients are found to be confin...

R. E. Meyer

1983-01-01

473

Thermal patterns in evaporating liquid  

Microsoft Academic Search

In this paper, some of the preparatory experiments of the ESA sponsored space program CIMEX-1 are presented. A liquid layer\\u000a of variable thickness is subject to a flow of inert gas. The non-uniform evaporation induced by the gas flow creates a temperature\\u000a gradient parallel to the interface triggering in that way thermocapillary convection. The combined action of evaporation,\\u000a thermocapillarity and

Carlo S. Iorio; Oleg A. Kabov; Jean-Claude Legros

2007-01-01

474

Outbreak of pan-susceptible Klebsiella pneumoniae in a neonatal intensive care unit.  

PubMed

Abstract We describe the outbreak of a pan-susceptible Klebsiella pneumoniae strain in a neonatal intensive care unit. A total of 7 neonates developed bacteraemia (37% attack rate), of whom 3 died (43% case fatality rate). A birth weight < 1500 g was the only statistically significant risk factor. Despite an extensive environmental investigation, the source was not identified. PMID:23902586

Maltezou, Helena C; Papacharalambous, Efthimia; Tryfinopoulou, Kyriaki; Ftika, Lemonia; Maragos, Antonios; Kyriakeli, Georgia; Katerelos, Panos; Trakateli, Christina; Polemis, Michalis; Roilides, Emmanuel; Vatopoulos, Alkiviadis; Nikolaidis, Nikolaos

2013-08-01

475

The Pan-STARRS Survey Telescope Project  

Microsoft Academic Search

The Institute for Astronomy at the University of Hawaii is developing a large optical\\/near-IR survey telescope system; the Panoramic Survey Telescope and Rapid Response System. Pan-STARRS will employ 1.8m optical imagers very large (7 square degree) field of view and revolutionary 1.4 billion pixel CCD cameras with low noise and rapid read-out to provide broad band imaging from 400-1000nm wavelength.

N. Kaiser

2007-01-01

476