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1

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

2

Changes in New Zealand pan evaporation since the 1970s  

NASA Astrophysics Data System (ADS)

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 whether the decline in evaporative demand is happening in other parts of the Southern Hemisphere. As a first step to addressing the latter question, we examined the trend in pan evaporation at 19 New Zealand sites. We found statistically significant declines in pan evaporation rate at 6 of the 19 sites. There were no sites with statistically significant increases in pan evaporation. When averaged across all 19 sites, the decline in pan evaporation rate was roughly 2 mm a-2 (i.e. mm per annum per annum) since the 1970s. Over a 30-year period, this is equivalent to a decline of about 60 mm a-1 in annual pan evaporation. These results are generally consistent with those reported throughout the Northern Hemisphere and in Australia. We conclude that the trend for decreasing evaporative demand previously reported throughout the Northern Hemisphere terrestrial surface may also be widespread in the Southern Hemisphere. This may be, in part, a greenhouse-related phenomenon.

Roderick, Michael L.; Farquhar, Graham D.

2005-12-01

3

Pan Evaporation in the Southern Hemisphere: What is Happening ?  

NASA Astrophysics Data System (ADS)

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 there have been no studies from the southern hemisphere. In this talk, we report data from Australia showing a decline in the pan evaporation rate over the last 30 years (- 4 mm a-2) of more or less the same magnitude as the northern hemisphere trends. These results show that regions of the southern hemisphere are becoming less arid just like the northern hemisphere. The most likely reason is the enhanced greenhouse effect.

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

2004-05-01

4

Changes in Australian pan evaporation from 1970 to 2002  

NASA Astrophysics Data System (ADS)

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 Hemisphere has until now been unknown because there have been no reports from the Southern Hemisphere. Here, we report a decrease in pan evaporation rate over the last 30 years across Australia of the same magnitude as the Northern Hemisphere trends (approximately -4 mm a-2). The results show that the terrestrial surface in Australia has, on average, become less arid over the recent past, just like much of the Northern Hemisphere.

Roderick, Michael L.; Farquhar, Graham D.

2004-07-01

5

Evaporation Rate on Tungsten  

E-print Network

Cesium Evaporation Rate on Tungsten Photocathodes Ameerah Jabr-Hamdan Introduction Motivation Research Objective Experiments Results Conclusions Cesium Evaporation Rate on Tungsten Photocathodes supported by IREAP, with funding from NSF and ONR #12;Cesium Evaporation Rate on Tungsten Photocathodes

Anlage, Steven

6

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

NASA Astrophysics Data System (ADS)

Oxygen and hydrogen isotope variations monitored in Lake Massaciuccoli (7 km2, 2 m deep, seasonally variable water level) during summer 2008, were compared with those observed in a Class A evaporation pan (diameter 120.6 cm, depth 25.4 cm) placed on the lake eastern shore. Air temperature, pressure, relative humidity, wind speed and direction, solar radiation, water temperature in the lake and the pan were also measured. The pluviometer indicated that no precipitation occurred during the study period. The pan was initially filled with groundwater up to the level of 19.2 cm (219 L), depleted in heavy isotopes with respect to tha lake water. Sodium chloride was added up to the concentration of 1 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

7

Detecting inhomogeneities in pan evaporation time series  

NASA Astrophysics Data System (ADS)

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 Australia, and illustrates the benefit of using corrected records in climate studies. The two tests being the bivariate test of Maronna and Yohai (1978), also known as the Potter method (WMO 2003), and the RHTest of Wang and Feng (2004). Overall, 58 per cent of the inhomogeneities detected by the bivariate test were also identified by the RHTest. The fact that the other 42 per cent of inhomogeneities were not consistently detected is due to different sensitivities of the two methods. Ninety-two per cent of the inhomogeneities detected by the bivariate test are consistent with documented changes that can be strongly associated with the discontinuity. Having identified inhomogeneities, the adjusments were only applied to records which contained inhomogeneities that could be verified as having a non-climatic origin. The benefit of using the original and adjusted pan evaporation records in a climate study were then investigated from two points of view: correlation analyses and trend analysis. As an illustration, the results show that the trend (1970-2004) in the all-stations average was -2.8±1.7 for the original data but only -0.7±1.6 mm/year/year for the adjusted data, demonstrating the importance of screening the data before their use in climate studies. References Maronna, R. and Yohai, V.J. 1978. A bivariate test for the detection of a systematic change in mean. J. Amer. Statis. Assoc., 73, 640-645. Wang, X.L. and Feng, Y. 2004. RHTest User manual. Available from http://cccma.seos.uvic.ca/ETCCDMI/RHTestUserManual.doc WMO. 2003. Guidelines on climate metadata and homogenization. WCDMP-No. 53, WMO-TD No. 1186, World Meteorological Organization, Geneva, Switzerland, 51 pp.

Kirono, D. G. C.

2009-04-01

8

Pan Evaporation, Relative Humidity and Daily Minimum/Maximum Temperatures  

NSDL National Science Digital Library

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

9

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

10

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

11

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture...and Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers...

2014-01-01

12

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...and Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers...

2010-01-01

13

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture...and Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers...

2013-01-01

14

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture...and Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers...

2012-01-01

15

7 CFR 58.217 - Evaporators and/or vacuum pans.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Evaporators and/or vacuum pans. 58.217 Section 58.217 Agriculture...and Utensils § 58.217 Evaporators and/or vacuum pans. Evaporators or vacuum pans or both, with open type condensers...

2011-01-01

16

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. PMID:23226984

Almedeij, Jaber

2012-01-01

17

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

18

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

E-print Network

Trends in pan evaporation and actual evapotranspiration across the conterminous U.S.: Paradoxical-century. Comparing trends in ETpan and water budget-derived actual evapotranspiration (ET*a), we observe the so between actual evapotranspiration (ETa) and potential evapotranspiration (ETp). Examining trends

Ramírez, Jorge A.

19

Utility of PenmanMonteith, PriestleyTaylor, reference evapotranspiration, and pan evaporation methods to estimate  

E-print Network

Utility of Penman­Monteith, Priestley­Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration David M. Sumnera,*, Jennifer M. Jacobsb,1 a United States October 2004; accepted 29 October 2004 Abstract Actual evapotranspiration (ETa) was measured at 30-min

20

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

21

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

22

Evaporation rate of water in hydrophobic confinement  

PubMed Central

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 nm2), 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 50kT and are predominantly enthalpic. Evaporation rates per unit area are found to be two orders of magnitude faster in confinement by the larger (9 nm2) than by the smaller (1 nm2) 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.

2012-01-01

23

Evaporation rate of emulsion and oil-base emulsion pheromones  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowledge of pheromone evaporation rate is critical to distribute pheromone containers effectively in the forest, orchard and field. There are several factors influencing the pheromone evaporation rate that include wind speed, container size and porosity, release area, temperature, humidity, pherom...

24

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.

James H. Kessler

2007-01-01

25

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

26

Vapor-based interferometric measurement of local evaporation rate and interfacial temperature of evaporating droplets.  

PubMed

The local evaporation rate and interfacial temperature are two quintessential characteristics for the study of evaporating droplets. Here, it is shown how one can extract these quantities by measuring the vapor concentration field around the droplet with digital holographic interferometry. As a concrete example, an evaporating freely receding pending droplet of 3M Novec HFE-7000 is analyzed at ambient conditions. The measured vapor cloud is shown to deviate significantly from a pure-diffusion regime calculation, but it compares favorably to a new boundary-layer theory accounting for a buoyancy-induced convection in the gas and the influence upon it of a thermal Marangoni flow. By integration of the measured local evaporation rate over the interface, the global evaporation rate is obtained and validated by a side-view measurement of the droplet shape. Advective effects are found to boost the global evaporation rate by a factor of 4 as compared to the diffusion-limited theory. PMID:24506092

Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

2014-03-01

27

Evaporation rate and vapor pressure of selected polymeric lubricating oils.  

NASA Technical Reports Server (NTRS)

A recently developed ultrahigh-vacuum quartz spring mass sorption microbalance has been utilized to measure the evaporation rates of several low-volatility polymeric lubricating oils at various temperatures. The evaporation rates are used to calculate the vapor pressures by the Langmuir equation. A method is presented to accurately estimate extended temperature range evaporation rate and vapor pressure data for polymeric oils, incorporating appropriate corrections for the increases in molecular weight and the change in volatility of the progressively evaporating polymer fractions. The logarithms of the calculated data appear to follow linear relationships within the test temperature ranges, when plotted versus 1000/T. These functions and the observed effusion characteristics of the fluids on progressive volatilization are useful in estimating evaporation rate and vapor pressure changes on evaporative depletion.

Gardos, M. N.

1973-01-01

28

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

PubMed

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

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

2013-11-01

29

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

30

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

31

Rate of Water Evaporation in Texas.  

E-print Network

.163 . Precipitation, inches 1 39 -49 .79 .84 1.73 2.82 2.84 3.20 2.39 1.72 1.05 .79 21.57 Mean max. temp. Mean min. temp. Mean mean temp. Av. rel. humidity Wind run, miles Big Spring: Evaporation, inches Precipitation, inches Mean max. temB. Mean min. temp....379 16.420 8.047 7.320 7.06818.580 6.178 6.890 6.864 7.167 5.643 4.816 7.780 6.688 7.859 8.773 7.807 7.123 8.184 7.573 8.500 7.200 6.260 7.403 4.746 6.775 5.664 6.477 6.855 7.000 8.494 6.400 6.144 6.017 6.907 8.586 6...

Karper, R. E. (Robert Earl)

1933-01-01

32

Regional rates of sweat evaporation during leg and arm cycling.  

PubMed Central

The rate of sweat evaporation from the arm, chest, back and thigh, aural temperature, skin temperature (arm, chest, back and thigh), heat production (derived from measurements of respiratory gas exchange) and heart rate were measured in 7 men during 15 minutes of leg or arm cycling at 32% of predicted maximum oxygen uptake (VO2 max). The regional sweat evaporation rates and changes in body temperature were similar during both forms of exercise. The peak rates of sweat evaporation from the arm, chest, back and thigh were 15.7 +/- 19.8, 25.0 +/- 21.6, 28.7 +/- 22.7 and 21.0 +/- 18.2 mg.cm-2 hr-1 during leg cycling and 13.2 +/- 11.6, 22.2 +/- 14.4, 27.6 +/- 14.7 and 19.2 +/- 13.3 (SD) mg.cm-2 hr-1 respectively during arm cycling. The sweat evaporation rates from the different body regions were not significantly different from one another. PMID:3697601

Ayling, J H

1986-01-01

33

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.

34

Mechanisms of solvent evaporation encapsulation processes: prediction of solvent evaporation rate.  

PubMed

The mechanism of organic solvent evaporation during microencapsulation and its role during microsphere hardening has been investigated. Evaporation and encapsulation studies were carried out in a jacketed beaker, filled with aqueous hardening solution, which was maintained at constant temperature and constant stirring rate in the turbulent regime. Evaporation of dissolved methylene chloride (MC), ethyl acetate (EA), and acetonitrile (ACN) was examined by the decline in organic solvent concentration in the hardening bath, which was monitored by gas chromatography. The evaporation from the bath followed first-order kinetics under dilute conditions (e.g., MC < 3 mg/mL), yielding an overall permeability coefficient, P. The value of P was theoretically related to the Kolmogorov length-scale of turbulence under conditions that favor liquid-side transport control. According to theory, factors that favored liquid-phase control (as opposed to gas-phase control) were those that favored a high Henry's law constant [i.e., elevated temperature near the normal boiling point (bp) of the organic solvent] and properties of the dissolved organic solvent (i.e., low normal bp and low aqueous solubility). These theoretical hypotheses were confirmed by (1) correlating the experimentally determined P with process variables raised to the appropriate power according to theory, r(2) = 0.95 (i.e., P approximately rotational speed, omega(3/4), impeller diameter, d (5/4), volume of hardening bath, V(-1/4), and the product of kinematic viscosity and diffusion coefficient, nu(-5/12)D (2/3)), and (2) illustrating that at constant temperature, the tendency of the evaporation system to obey liquid-side transport control follows the same order of increasing Henry's law constant (i.e., MC > EA > ACN). To establish the relationship of evaporation with microsphere hardening, the decline in MC concentration was determined in both the continuous and dispersed polymer phases during microencapsulation. By applying a mass balance with respect to MC in the hardening bath, the cumulative hardening profile of the microspheres was accurately predicted from the interpolating functions of the kinetics of MC loss from the bath with and without polymer added. These results have potential use for microsphere formulation, design of encapsulation apparatus, and scale up of microsphere production. PMID:10514360

Wang, J; Schwendeman, S P

1999-10-01

35

A comparison of methods for estimating open-water evaporation in small wetlands  

USGS Publications Warehouse

We compared evaporation measurements from a floating pan, land pan, chamber, and the Priestley-Taylor (PT) equation. Floating pan, land pan, and meteorological data were collected from June 6 to July 21, 2005, at a small wetland in the Canadian River alluvium in central Oklahoma, USA. Evaporation measured with the floating pan compared favorably to 12 h chamber measurements. Differences between chamber and floating pan rates ranged from ?0.2 to 0.3 mm, mean of 0.1 mm. The difference between chamber and land pan rates ranged from 0.8 to 2.0 mm, mean of 1.5 mm. The mean chamber-to-floating pan ratio was 0.97 and the mean chamber-to-land pan ratio was 0.73. The chamber-to-floating pan ratio of 0.97 indicates the use of a floating pan to measure evaporation in small limited-fetch water bodies is an appropriate and accurate method for the site investigated. One-sided Paired t-Tests indicate daily floating pan rates were significantly less than land pan and PT rates. A two-sided Paired t-Test indicated there was no significant difference between land pan and PT values. The PT equation tends to overestimate evaporation during times when the air is of low drying power and tends to underestimate as drying power increases.

Masoner, Jason R.; Stannard, David I.

2010-01-01

36

Studying biofuel aerosol evaporation rates with single particle manipulation  

NASA Astrophysics Data System (ADS)

The significant increase in the air pollution, and the impact on climate change due to the burning of fossil fuel has led to the research of alternative energies. Bio-ethanol obtained from a variety of feedstocks can provide a feasible solution. Mixing bio-ethanol with gasoline leads to a reduction in CO emission and in NOx emissions compared with the use of gasoline alone. However, adding ethanol leads to a change in the fuel evaporation. Here we present a preliminary investigation of evaporation times of single ethanol-gasoline droplets. In particular, we investigated the different evaporation rate of the droplets depending on the variation in the percentage of ethanol inside them. Two different techniques have been used to trap the droplets. One makes use of a 532nm optical tweezers set up, the other of an electrodynamics balance (EDB). The droplets decreasing size was measured using video analysis and elastic light scattering respectively. In the first case measurements were conducted at 293.15 K and ambient humidity. In the second case at 280.5 K and a controlled environment has been preserved by flowing nitrogen into the chamber. Binary phase droplets with a higher percentage of ethanol resulted in longer droplet lifetimes. Our work also highlights the advantages and disadvantages of each technique for such studies. In particular it is challenging to trap droplets with low ethanol content (such as pure gasoline) by the use of EDB. Conversely such droplets are trivial to trap using optical tweezers.

Corsetti, S.; Miles, R. E. H.; Reid, J. P.; Kiefer, J.; McGloin, D.

2014-09-01

37

Black Hole Evaporation Rates without Spacetime Samuel L. Braunstein and Manas K. Patra  

E-print Network

Black Hole Evaporation Rates without Spacetime Samuel L. Braunstein and Manas K. Patra Computer tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes

Braunstein, Samuel L.

38

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

NASA Technical Reports Server (NTRS)

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

Auer, S.

1976-01-01

39

Evaporation rates of pasture-mesquite vegetation in central Mexico  

NASA Astrophysics Data System (ADS)

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

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

2004-12-01

40

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

41

Evaporation Rates of Oxides from Undoped and Sb-Doped Si Melts under Atmospheres of Pure Ne, Ar, and Kr  

NASA Astrophysics Data System (ADS)

The effect of gaseous Ne, Ar, and Kr on the evaporation rates of oxides from undoped and Sb-doped Si melts was investigated. By measuring the weight loss of a melt using a thermogravimetric method, we determined the evaporation rate of different species from the melts. The measurements were done at a melt temperature of 1442° C and a background gas pressure of 1.02 atm. Because Ar is predominantly used as the background gas in the semiconductor industry, we report evaporation rates relative to the rates under an atmosphere of pure Ar. For the evaporation of SiO from an undoped Si melt, Ne enhanced the evaporation rate by 37% and Kr suppressed the evaporation rate by 13%. For the evaporation of antimony from an Sb-doped Si melt, Ne enhanced the evaporation rate by 18% and Kr suppressed the evaporation rate by 24%. For the evaporation of antimony oxide from an Sb-doped melt, Ne enhanced the evaporation rate by 4% and Kr suppressed the evaporation rate by 63%. We therefore conclude that, compared with Ar, Ne enhances and Kr suppresses the evaporation of oxides from undoped and Sb-doped Si melts. We show that the background gas affects evaporation through gas-phase diffusion; the diffusion coefficient of the evaporating species is the highest in Ne and the lowest in Kr. In addition, we show that the transport of the evaporating species in the melt to the surface also influences the overall evaporation rates.

Huang, Xinming; Terashima, Kazutaka; Tokizaki, Eiji; Kimura, Shigeyuki; Whitby, Evan

1994-07-01

42

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

43

The rates at which terrestrial animals lose water through evaporation across the skin and respiratory surfaces  

E-print Network

and respiratory surfaces have important consequences for their water balance, thermoregulation and survivalThe rates at which terrestrial animals lose water through evaporation across the skin required the minimization of evaporative water losses. In response to these demands, animals have evolved

Wolf, Blair O.

44

Effects on evaporation rates from different water-permeable pavement designs.  

PubMed

The urban water balance can be attenuated to the natural by water-permeable pavements (WPPs). Furthermore, WPPs have a 16% higher evaporation rate than impermeable pavements, which can lead to a better urban climate. Evaporation rates from pavements are influenced by the pavement surface and by the deeper layers. By a compared evaporation measurement between different WPP designs, the grain size distribution of the sub-base shows no influence on the evaporation rates in a significant way. On the contrary, a sub-base made of a twin-layer decreases the evaporation by 16% compared to a homogeneous sub-base. By a change in the colour of the paving stone, 19% higher evaporation rates could be achieved. A further comparison shows that the transpiration-effect of the grass in grass pavers increases the evaporation rates more than threefold to pervious concrete pavements. These high evapotranspiration rates can not be achieved with a pervious concrete paving stone. In spite of this, the broad field of application of the pervious concrete paving stone increases the importance in regard to the urban climate. PMID:22049757

Starke, P; Göbel, P; Coldewey, W G

2011-01-01

45

Does non-ionizing radiant energy affect determination of the evaporation rate by the gradient method?  

PubMed

A study was performed to investigate whether measurements of the evaporation rate from the skin of newborn infants by the gradient method are affected by the presence of non-ionizing radiation from phototherapy equipment or a radiant heater. The evaporation rate was measured experimentally with the measuring sensors either exposed to or protected from non-ionizing radiation. Either blue light (phototherapy) or infrared light (radiant heater) was used; in the former case the evaporation rate was measured from a beaker of water covered with a semipermeable membrane, and in the latter case from the hand of an adult subject, aluminium foil or with the measuring probe in the air. No adverse effect on the determinations of the evaporation rate was found in the presence of blue light. Infrared radiation caused an error of 0.8 g/m2h when the radiant heater was set at its highest effect level or when the ambient humidity was high. At low and moderate levels the observed evaporation rate was not affected. It is concluded that when clinical measurements are made from the skin of newborn infants nursed under a radiant heater, the evaporation rate can appropriately be determined by the gradient method. PMID:1897061

Kjartansson, S; Hammarlund, K; Oberg, P A; Sedin, G

1991-01-01

46

Evaporation Loss of Light Elements as a Function of Cooling Rate: Logarithmic Law  

NASA Technical Reports Server (NTRS)

Knowledge about the evaporation loss of light elements is important to our understanding of chondrule formation processes. The evaporative loss of light elements (such as B and Li) as a function of cooling rate is of special interest because recent investigations of the distribution of Li, Be and B in meteoritic chondrules have revealed that Li varies by 25 times, and B and Be varies by about 10 times. Therefore, if we can extrapolate and interpolate with confidence the evaporation loss of B and Li (and other light elements such as K, Na) at a wide range of cooling rates of interest based upon limited experimental data, we would be able to assess the full range of scenarios relating to chondrule formation processes. Here, we propose that evaporation loss of light elements as a function of cooling rate should obey the logarithmic law.

Xiong, Yong-Liang; Hewins, Roger H.

2003-01-01

47

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

48

The use of thermogravimetry to follow the rate of evaporation of an ingredient used in perfumes  

Microsoft Academic Search

Ingredients used in the manufacture of perfumes can be investigated by thermogravimetry. In this study the evaporation of\\u000a methyl benzoate was investigated using a simultaneous TG-DTA unit. A rising temperature method of thermal analysis was used\\u000a for the study. The rate of evaporation of the ingredient was calculated from a simple plot of percentage mass lossvs. time. A derivative plot

P. Aggarwal; D. Dollimore; K. Alexander

1997-01-01

49

High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation  

Microsoft Academic Search

Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm\\/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of

Tadatsugu Minami; Satoshi Ida; Toshihiro Miyata

2002-01-01

50

Influence of solvent evaporation rate and formulation factors on solid dispersion physical stability.  

PubMed

New chemical entities (NCEs) often show poor water solubility necessitating solid dispersion formulation. The aim of the current study is to employ design of experiments in investigating the influence of one critical process factor (solvent evaporation rate) and two formulation factors (PVP:piroxicam ratio (PVP:PRX) and PVP molecular weight (P(MW))) on the physical stability of PRX solid dispersion prepared by the solvent evaporation method. The results showed the rank order of an increase in factors contributing to a decrease in the extent of PRX nucleation being evaporation rate>PVP:PRX>P(MW). The same rank order was found for the decrease in the extent of PRX crystal growth in PVP matrices from day 0 up to day 12. However, after 12days the rank became PVP:PRX>evaporation rate>P(MW). The effects of an increase in evaporation rate and PVP:PRX ratio in stabilizing PRX were of the same order of magnitude, while the effect from P(MW) was much smaller. The findings were confirmed by XRPD. FT-IR showed that PRX recrystallization in the PVP matrix followed Ostwald's step rule, and an increase in the three factors all led to increased hydrogen bonding interaction between PRX and PVP. The present study showed the applicability of the Quality by Design approach in solid dispersion research, and highlights the need for multifactorial analysis. PMID:22024381

Wu, Jian X; Yang, Mingshi; Berg, Frans van den; Pajander, Jari; Rades, Thomas; Rantanen, Jukka

2011-12-18

51

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

PubMed

Although the requirements for heat dissipation during exercise are determined by the necessity for heat balance, few studies have considered them when examining sweat production and its potential modulators. Rather, the majority of studies have used an experimental protocol based on a fixed percentage of maximum oxygen uptake (% ). Using multiple regression analysis, we examined the independent contribution of the evaporative requirement for heat balance (Ereq) and % to whole-body sweat rate (WBSR) during exercise. We hypothesised that WBSR would be determined by Ereq and not by % . A total of 23 males performed two separate experiments during which they exercised for 90 min at different rates of metabolic heat production (200, 350, 500 W) at a fixed air temperature (30°C, n = 8), or at a fixed rate of metabolic heat production (290 W) at different air temperatures (30, 35, 40°C, n = 15 and 45°C, n = 7). Whole-body evaporative heat loss was measured by direct calorimetry and used to calculate absolute WBSR in grams per minute. The conditions employed resulted in a wide range of Ereq (131-487 W) and % (15-55%). The individual variation in non-steady-state (0-30 min) and steady-state (30-90 min) WBSR correlated significantly with Ereq (P < 0.001). In contrast, % correlated negatively with the residual variation in WBSR not explained by Ereq, and marginally increased (?2%) the amount of total variability in WBSR described by Ereq alone (non-steady state: R(2) = 0.885; steady state: R(2) = 0.930). These data provide clear evidence that absolute WBSR during exercise is determined by Ereq, not by % . Future studies should therefore use an experimental protocol which ensures a fixed Ereq when examining absolute WBSR between individuals, irrespective of potential differences in relative exercise intensity. PMID:23459754

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

2013-06-01

52

Accurate evaporation rates of pure and doped water clusters in vacuum: A statistico-dynamical approach  

NASA Astrophysics Data System (ADS)

Unimolecular evaporation of selected pure (H2O)n and heterogeneous (H2O)n-1X+ water clusters containing a single hydronium or ammonium impurity is investigated in the framework of phase space theory (PST) in its orbiting transition state version. Using the many-body polarizable Kozack-Jordan potential and its extensions for X+=H3O+ and NH4+, the thermal evaporation of clusters containing 21 and 50 molecules is simulated at several total energies. Numerous molecular dynamics (MD) trajectories at high internal energies provide estimates of the decay rate constant, as well as the kinetic energy and angular momentum released upon dissociation. Additional Monte Carlo simulations are carried out to determine the anharmonic densities of vibrational states, which combined with suitable forms for the rotational densities of states provide expressions for the energy-resolved differential rates. Successful comparison between the MD results and the independent predictions of PST for the distributions of kinetic energy and angular momentum released shows that the latter statistical approach is quantitative. Using MD data as a reference, the absolute evaporation rates are calculated from PST over broad energy and temperature ranges. Based on these results, the presence of an ionic impurity is generally found to decrease the rate, however the effect is much more significant in the 21-molecule clusters. Our calculations also suggest that due to backbendings in the microcanonical densities of states the variations of the evaporation rates may not be strictly increasing with energy or temperature.

Calvo, F.; Douady, J.; Spiegelman, F.

2010-01-01

53

Influence of a wick lining on the evaporation rate of lithium from a charge exchange canal  

NASA Astrophysics Data System (ADS)

A wick lining is used with a lithium charge exchange canal for reducing the consumption of lithium. The wick helps to condense the lithium vapour more effectively and to make it flow back to the main oven. For its efficient functioning, the temperature gradient along the wick has to be properly maintained. The present studies were carried out to assess the extent of reduction in lithium loss when using the wick and to determine the optimum temperature settings. The evaporation rate of lithium vapour from a charge exchange canal (General Ionex Model-712) has been investigated in the temperature range from 470 to 575° C. The measurements were carried out with and without a stainless steel wire mesh wick lining, inside the canal. A quartz crystal oscillator type rate meter was used for monitoring the evaporation rate. The results indicate that, when the wick lining is inserted, the reduction in evaporation rate of lithium is only 20%. This differs much from the result of Greenway [Report 85/11, Oxford University, Nuclear Physics Laboratory (1985)] who reported a reduction by a factor of 8. The evaporation rate is also found to depend on the canal end heater temperature, maintained high enough to keep the condensing vapour in liquid state. The optimum temperature settings for the end heaters have been found to be 300 ° C. The experimental arrangements and results are presented in this paper.

Thampi, N. S.; Berger, S.; Dworschak, F.

1992-02-01

54

Evaporation rate from square capillaries limited by corner flow viscous losses  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

55

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...

56

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

57

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...

58

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

59

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

60

Evaporation Rates for Liquid Water and Ice Under Current Martian Conditions  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

61

Maximum Evaporation Rates of Water Droplets Approaching Obstacles in the Atmosphere Under Icing Conditions  

NASA Technical Reports Server (NTRS)

When a closed body or a duct envelope moves through the atmosphere, air pressure and temperature rises occur ahead of the body or, under ram conditions, within the duct. If cloud water droplets are encountered, droplet evaporation will result because of the air-temperature rise and the relative velocity between the droplet and stagnating air. It is shown that the solution of the steady-state psychrometric equation provides evaporation rates which are the maximum possible when droplets are entrained in air moving along stagnation lines under such conditions. Calculations are made for a wide variety of water droplet diameters, ambient conditions, and flight Mach numbers. Droplet diameter, body size, and Mach number effects are found to predominate, whereas wide variation in ambient conditions are of relatively small significance in the determination of evaporation rates. The results are essentially exact for the case of movement of droplets having diameters smaller than about 30 microns along relatively long ducts (length at least several feet) or toward large obstacles (wings), since disequilibrium effects are then of little significance. Mass losses in the case of movement within ducts will often be significant fractions (one-fifth to one-half) of original droplet masses, while very small droplets within ducts will often disappear even though the entraining air is not fully stagnated. Wing-approach evaporation losses will usually be of the order of several percent of original droplet masses. Two numerical examples are given of the determination of local evaporation rates and total mass losses in cases involving cloud droplets approaching circular cylinders along stagnation lines. The cylinders chosen were of 3.95-inch (10.0+ cm) diameter and 39.5-inch 100+ cm) diameter. The smaller is representative of icing-rate measurement cylinders, while with the larger will be associated an air-flow field similar to that ahead of an airfoil having a leading-edge radius comparable with that of the cylinder. It is found that the losses are less than 5 percent. It is concluded that such losses are, in general, very small (less than 1 percent) in the case of smaller obstacles (of icing-rate measurement- cylinder size); the motional dynamics are such, however, that exceptions will occur by reason of failure of very small droplets (moving along stagnation lines) to impinge upon obstacle surfaces. In such cases, the droplets will evaporate completely.

Lowell, H. H.

1953-01-01

62

Mechanical tuning of the evaporation rate of liquid on crossed fibers.  

PubMed

We investigate experimentally the drying of a small volume of perfectly wetting liquid on two crossed fibers. We characterize the drying dynamics for the three liquid morphologies that are encountered in this geometry: drop, column, and a mixed morphology, in which a drop and a column coexist. For each morphology, we rationalize our findings with theoretical models that capture the drying kinetics. We find that the evaporation rate significantly depends upon the liquid morphology and that the drying of the liquid column is faster than the evaporation of the drop and the mixed morphology for a given liquid volume. Finally, we illustrate that shearing a network of fibers reduces the angle between them, changes the morphology toward the column state, and therefore, enhances the drying rate of a volatile liquid deposited on it. PMID:25716158

Boulogne, François; Sauret, Alban; Soh, Beatrice; Dressaire, Emilie; Stone, Howard A

2015-03-17

63

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

John Eichinger

2009-05-15

64

Finite-mass correction to 2D black-hole evaporation rate  

NASA Astrophysics Data System (ADS)

We numerically analyze the evolution of a two-dimensional dilatonic black hole, within the Callan-Giddings-Harvey-Strominger model. We focus our attention on the finite-mass corrections to the universal evaporation rate which applies at the large-mass limit. Our numerical results confirm a previous theoretical prediction for the first-order (?1/M) correction. In addition, our results strongly suggest that the next-order (?1/M2) term vanishes and provide a rough estimate for the third-order term.

Dori, Liora; Ori, Amos

2012-06-01

65

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

66

Milagro limits and HAWC sensitivity for the rate-density of evaporating Primordial Black Holes  

NASA Astrophysics Data System (ADS)

Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations in the early universe and could have arbitrarily small masses down to the Planck scale. Hawking showed that due to quantum effects, a black hole has a temperature inversely proportional to its mass and will emit all species of fundamental particles thermally. PBHs with initial masses of ?5.0 × 1014 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV-TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.

Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B. T.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Aune, T.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carramiñana, A.; Castillo, M.; Christopher, G. E.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hays, E.; Hoffman, C. M.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kolterman, B. E.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-GarcIa, R.; MacGibbon, J. H.; Marinelli, A.; Marinelli, S. S.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Mincer, A. I.; Miranda-Romagnoli, P.; Moreno, E.; Morgan, T.; Mostafá, M.; Nellen, L.; Nemethy, P.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Rivière, C.; Rosa-González, D.; Ruiz-Velasco, E.; Ryan, J.; Salazar, H.; Salesa, F.; Sandoval, A.; Saz Parkinson, P. M.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Stump, D.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Vasileiou, V.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Williams, D. A.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.

2015-04-01

67

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

68

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

69

Waking to drink: rates of evaporative water loss determine arousal frequency in hibernating bats.  

PubMed

Bats hibernate to cope with low ambient temperatures (T(a)) and low food availability during winter. However, hibernation is frequently interrupted by arousals, when bats increase body temperature (T(b)) and metabolic rate (MR) to normothermic levels. Arousals account for more than 85% of a bat's winter energy expenditure. This has been associated with variation in T(b), T(a) or both, leading to a single testable prediction, i.e. that torpor bout length (TBL) is negatively correlated with T(a) and T(b). T(a) and T(b) were both found to be correlated with TBL, but correlations alone cannot establish a causal link between arousal and T(b) or T(a). Because hydration state has also been implicated in arousals from hibernation, we hypothesized that water loss during hibernation creates the need in bats to arouse to drink. We measured TBL of bats (Pipistrellus kuhlii) at the same T(a) but under different conditions of humidity, and found an inverse relationship between TBL and total evaporative water loss, independent of metabolic rate, which directly supports the hypothesis that hydration state is a cue to arousal in bats. PMID:23364570

Ben-Hamo, Miriam; Muñoz-Garcia, Agustí; Williams, Joseph B; Korine, Carmi; Pinshow, Berry

2013-02-15

70

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

PubMed

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 (C(surf)). C(surf) accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of C(surf) 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 C(surf) 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. PMID:23576717

Salvucci, Guido D; Gentine, Pierre

2013-04-16

71

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. PMID:23576717

Salvucci, Guido D.; Gentine, Pierre

2013-01-01

72

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

73

Metabolic rate and evaporative water loss in the silky starling (Sturnus sericeus).  

PubMed

To better understand the physiological characteristics of the silky starling (Sturnus sericeus), its body temperature (Tb), basal metabolic rate (BMR), evaporative water loss (EWL) and thermal conductance (C) elicited by different ambient temperatures (Ta) (5-30 ?) were determined in the present study. Our results showed that they have a high Tb (41.6 ± 0.1 ?), a wide thermal neutral zone (TNZ) (20-27.5?) and a relatively low BMR within the TNZ (3.37 ± 0.17 mL O?/g·h). The EWL was nearly stable below the TNZ (0.91 ± 0.07 mg H?O/g·h) but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14 ± 0.01 mL O?/g·h·?. These findings indicate that the BMR, Tb and EWL of the silky starling were all affected by Ta, especially when Ta was below 20 ? and the EWL plays an important role in thermal regulation. PMID:25017746

Bao, Huan-Huan; Liang, Qing-Jian; Zhu, Hong-Lei; Zhou, Xiao-Qiu; Zheng, Wei-Hong; Liu, Jin-Song

2014-07-01

74

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

PubMed

Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating, at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at 100, 38.5, and 7.3 kPa respectively by using a rotary evaporator. Applying microwave energy decreased required times to 115, 95, and 60 min. The changes in color, anthocyanin content during the concentration processes were investigated. Hunter parameters (L, a, and b) were measured to estimate the intensity of color loss. All Hunter color parameters decreased with time. Results showed that the degradation of color and consequently anthocyanins, was more pronounced in rotary evaporation compared to microwave heating method. PMID:24425885

Fazaeli, Mahboubeh; Hojjatpanah, Ghazale; Emam-Djomeh, Zahra

2013-02-01

75

A comparison of two techniques for measuring the relative rates of moisture evaporation from limited areas of the skin of Holstein, Jersey and Jersey-Brahman cattle  

E-print Network

gusbgf, groe4, age end 4ato of last salving of test aahaals ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 18 Average evaporation, respiration end pulse rates, rental aad skin tosperscuresl and aoeuaaalatlon of chlorides of breed-age groups fran Nsy 31... ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 31 gffesc of the lengths of tine antuals e?aice4 tesCing for evaporation rates . . . . . . . . . . . . . , . . . . . 34 sveraga races of evaporation in the three breo4 groups during periods ?hen neon daily tenpors- turos Nolo 'bole?snd above 80 9...

Motasem, Mohamed M

1964-01-01

76

Nano-structured Li3V2(PO4)3/carbon composite for high-rate lithium-ion batteries Anqiang Pan a,b  

E-print Network

Nano-structured Li3V2(PO4)3/carbon composite for high-rate lithium-ion batteries Anqiang Pan a2(PO4)3 High-power battery Nano-structured Li3V2(PO4)3/carbon composite (Li3V2(PO4)3/C) has been microscopy were used to characterize the structure of the composites. Li3V2(PO4)3 had particle sizes ofb50 nm

Cao, Guozhong

77

Effects of Carbonyl Bond and Metal Cluster Dissociation and Evaporation Rates on Predictions of Nanotube Production in HiPco  

NASA Technical Reports Server (NTRS)

The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNT) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the co-formation of CO2. It is shown that the production of CO2 is significantly greater for FeCO due to its lower bond energy as compared with that ofNiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

Scott, Carl D.; Smalley, Richard E.

2002-01-01

78

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

NASA Technical Reports Server (NTRS)

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

Zhang, Nengli; Chao, David F.

1999-01-01

79

Biology of Myotis thysanodes and M. lucifugus (Chiroptera: Vespertilionidae)—III. Metabolism, heart rate, breathing rate, evaporative water loss and general energetics  

Microsoft Academic Search

Oxygen consumption (OC), weight specific oxygen consumption (VO). heart rate (HR). breathing rate (RR) and evaporative water loss (EWL) differ in adult female Mrotis th.wrnodes and M. ~uc~~uficgus and are significantly related to thermoregulatory performance (regulating or conforming) and to reproductive condition but not to body composttion. spleen or adrenal weights or age class. 2. Multiple regression equation models of

EUGENE H. STUDIER

1976-01-01

80

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

PubMed

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

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

2013-11-01

81

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

82

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

83

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

NASA Technical Reports Server (NTRS)

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

Zhang, Neng-Li; Chao, David F.

2001-01-01

84

Evaporation Anisotropy of Forsterite  

NASA Astrophysics Data System (ADS)

Evaporation anisotropy of a synthetic single crystal of forsterite was investigated by high temperature vacuum experiments. The (001), (010), and (001) surfaces show microstructures characteristic for each surface. Obtained overall linear evaporation rates for the (001), (010), and (001) surfaces are ~17, ~7, and ~22 mm/hour, and the intrinsic evaporation rates, obtained by the change in surface microstructures, are ~10, ~4.5, and ~35 mm/hour, respectively. The difference between the intrinsic evaporation rates and overall rates can be regarded as contribution of dislocation, which is notable for the (100) and (010) surfaces and insignificant for the (001) surface. This is consistent with observed surface microstructures.

Ozawa, K.; Nagahara, H.; Morioka, M.

1996-03-01

85

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

86

Improved rate control for electron-beam evaporation and evaluation of optical performance improvements.  

PubMed

A new deposition-rate-control and electron-beam-gun (e-gun) strategy was developed that significantly reduces the growth-rate variations for e-beam-deposited SiO2 coatings. The resulting improvements in optical performance are evaluated for multilayer bandpass filters. The adverse effect of uneven silica-source depletion on coating spectral performances during long deposition runs is discussed. PMID:16539249

Gevelber, Michael; Xu, Bing; Smith, Douglas

2006-03-01

87

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

88

Data Mining Approach for Estimation Evaporation from Free Water Surface  

NASA Astrophysics Data System (ADS)

Evaporation is a fundamental parameter in the cycle of hydrology. In the present study, data mining method is used to developed evaporation models. Before modeling, air temperature, water temperature, solar radiation and relative humidity parameters are selected as parameters affecting evaporation. Decision Table, KStar, M5P, Pace Regression, M5`Rules, Neural Network, Regression, Simple Linear Regression and SMO Regression algorithms are used for modeling. Finally, the developed models are compared with measured daily pan evaporation values and Penman method. The comparisons show that there is a good agreement between results of M5P model and measured daily pan evaporation values.

Terzi, Ozlem

89

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

90

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

NASA Astrophysics Data System (ADS)

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

Oroud, Ibrahim M.

2011-12-01

91

Field-measured, hourly soil water evaporation stages in relation to reference evapotranspiration rate and soil air temperature ratio  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil water evaporation takes critical water supplies away from crops, especially in areas where both rainfall and irrigation water are limited. This study measured bare soil water evaporation from clay loam, silt loam, sandy loam, and fine sand soils. It found that on average almost half of the ir...

92

OLPPS PAN Reviewer Who is a PAN  

E-print Network

­ On-line Training, Module 5: Monitoring/Reviewing Prior to Check Date #12; OPTRS/EDB Online Processing Schedule] What does a PAN Reviewer do? PAN Reviewers review all transactions. The request must include: o Employee Name o Employee ID o Home Department o Employee Email Address o

Yamamoto, Keith

93

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

94

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

95

7-58 A commercial refrigerator with R-134a as the working fluid is considered. The evaporator inlet and exit states are specified. The mass flow rate of the refrigerant and the rate of heat rejected are to be  

E-print Network

7-22 7-58 A commercial refrigerator with R-134a as the working fluid is considered. The evaporator inlet and exit states are specified. The mass flow rate of the refrigerant and the rate of heat rejected are to be determined. Assumptions 1 The refrigerator operates steadily. 2 The kinetic and potential energy changes

Bahrami, Majid

96

Effects of carbonyl bond, metal cluster dissociation, and evaporation rates on predictions of nanotube production in high-pressure carbon monoxide  

NASA Technical Reports Server (NTRS)

The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the conformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

Scott, Carl D.; Smalley, Richard E.

2003-01-01

97

Evaporation Investigation  

NSDL National Science Digital Library

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

2012-08-03

98

Determination of evaporation rates and vapor pressures of very low volatility compounds: a study of the C4-C10 diacarboxylic acids  

NASA Astrophysics Data System (ADS)

A new method for the measurement of evaporation rates and vapor pressures of low volatility compounds was developed and was applied to the homologous C4-C10 dicarboxylic acids. Proton-transfer chemical ionization mass spectrometry was used to directly measure the temperature dependent evaporation rates of aerosol samples collected on a cold plate that could be heated at a known rate. The vapor pressures of the deposited compounds were derived from the observed evaporation rates through application of the Hertz-Knudsen equation. Temperature programmed desorption allows for quantification of the enthalpy (?Hvap) and entropy (?Svap) of vaporization of the diacids and will be described. A strong odd-even effect with respect to the total carbon number is observed in the derived diacid vapor pressures, consistent with previous measurements. However, the vapor pressures from this method tend to be lower than previous measurements. Though seen in the vapor pressure, no odd-even carbon chain length effect is discernible in the measured values of ?Hvap and ?Svap. Perhaps most importantly, these experimental results also suggest that residual solvent molecules (from the aerosol generation process) trapped in the diacid samples can have a considerable influence on the measured thermodynamic parameters and, if not properly accounted for, may give extraneous results.

Cappa, C. D.; Lovejoy, E. R.; Ravishankara, A. R.

2006-12-01

99

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

100

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

101

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

102

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.

Jeff DeLaBeaujardiere

2005-05-27

103

PanDAR: a wide-area, frame-rate, and full color lidar with foveated region using backfilling interpolation upsampling  

NASA Astrophysics Data System (ADS)

LIDAR devices for on-vehicle use need a wide field of view and good fidelity. For instance, a LIDAR for avoidance of landing collisions by a helicopter needs to see a wide field of view and show reasonable details of the area. The same is true for an online LIDAR scanning device placed on an automobile. In this paper, we describe a LIDAR system with full color and enhanced resolution that has an effective vertical scanning range of 60 degrees with a central 20 degree fovea. The extended range with fovea is achieved by using two standard Velodyne 32-HDL LIDARs placed head to head and counter rotating. The HDL LIDARS each scan 40 degrees vertical and a full 360 degrees horizontal with an outdoor effective range of 100 meters. By positioning them head to head, they overlap by 20 degrees. This creates a double density fovea. The LIDAR returns from the two Velodyne sensors do not natively contain color. In order to add color, a Point Grey LadyBug panoramic camera is used to gather color data of the scene. In the first stage of our system, the two LIDAR point clouds and the LadyBug video are fused in real time at a frame rate of 10 Hz. A second stage is used to intelligently interpolate the point cloud and increase its resolution by approximately four times while maintaining accuracy with respect to the 3D scene. By using GPGPU programming, we can compute this at 10 Hz. Our backfilling interpolation methods works by first computing local linear approximations from the perspective of the LIDAR depth map. The color features from the image are used to select point cloud support points that are the best points in a local group for building the local linear approximations. This makes the colored point cloud more detailed while maintaining fidelity to the 3D scene. Our system also makes objects appearing in the PanDAR display easier to recognize for a human operator.

Mundhenk, T. Nathan; Kim, Kyungnam; Owechko, Yuri

2015-01-01

104

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

105

Effect of argon gas flow rate on properties of film electrodes prepared by thermal vacuum evaporation from synthesized Cu{sub 2}SnSe{sub 3} source  

SciTech Connect

This work describes a new technique to enhance photoresponse of metal chalcogenide-based semiconductor film electrodes deposited by thermal vacuum evaporation under argon gas flow from synthesized Cu{sub 2}SnSe{sub 3} sources. SnSe formation with Cu-doped was obtained under higher argon gas flow rate (V{sub A} = 25 cm{sup 3}/min). Higher value of photoresponse was observed for films deposited under V{sub A} = 25 cm{sup 3}/min which was 9.1%. This finding indicates that Cu atoms inside the SnSe film were important to increase carrier concentrations that promote higher photoresponse.

Sabli, Nordin; Talib, Zainal Abidin; Yunus, Wan Mahmood Mat [Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang (Malaysia); Zainal, Zulkarnain [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang (Malaysia); Hilal, Hikmat S. [SSERL, Department of Chemistry An-Najah N. University, PO Box 7, Nablus, West Bank (Country Unknown); Fujii, Masatoshi [Department of Molecular Science, School of Medicine, Shimane University, Izumo, Shimane, 693-8501 (Japan)

2014-03-05

106

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

107

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

108

Pan Balance - Numbers  

NSDL National Science Digital Library

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

National Council of Teachers of Mathematics

2009-07-22

109

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

110

Evaporative Cooler  

NSDL National Science Digital Library

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

2012-07-19

111

Evaporating firewalls  

NASA Astrophysics Data System (ADS)

In this note, we begin by presenting an argument suggesting that large AdS black holes dual to typical high-energy pure states of a single holographic CFT must have some structure at the horizon, i.e. a fuzzball/firewall, unless the procedure to probe physics behind the horizon is state-dependent. By weakly coupling the CFT to an auxiliary system, such a black hole can be made to evaporate. In a case where the auxiliary system is a second identical CFT, it is possible (for specific initial states) that the system evolves to precisely the thermofield double state as the original black hole evaporates. In this case, the dual geometry should include the "late-time" part of the eternal AdS black hole spacetime which includes smooth spacetime behind the horizon of the original black hole. Thus, if a firewall is present initially, it evaporates. This provides a specific realization of the recent ideas of Maldacena and Susskind that the existence of smooth spacetime behind the horizon of an evaporating black hole can be enabled by maximal entanglement with a Hawking radiation system (in our case the second CFT) rather than prevented by it. For initial states which are not finely-tuned to produce the thermofield double state, the question of whether a late-time infalling observer experiences a firewall translates to a question about the gravity dual of a typical high-energy state of a two-CFT system.

Van Raamsdonk, Mark

2014-11-01

112

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

113

Streamer Evaporation  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

114

PAN Pesticide Database  

NSDL National Science Digital Library

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

0000-00-00

115

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

116

Marangoni Convection and Deviations from Maxwells' Evaporation Model  

NASA Technical Reports Server (NTRS)

We investigate the convective dynamics of evaporating pools of volatile liquids using an ultra-sensitive thermal imaging camera. During evaporation, there are significant convective flows inside the liquid due to Marangoni forces. We find that Marangoni convection during evaporation can dramatically affect the evaporation rates of volatile liquids. A simple heat balance model connects the convective velocities and temperature gradients to the evaporation rates.

Segre, P. N.; Snell, E. H.; Adamek, D. H.

2003-01-01

117

49 CFR 230.69 - Ash pans.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans § 230.69 Ash pans. Ash pans shall be securely supported from mud-rings or frames with no part less...

2010-10-01

118

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

119

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

120

Tear Water Evaporation and Eye Surface Diseases  

Microsoft Academic Search

The water evaporation rate from the tear film of eyes with anterior surface pathology (corneal and\\/or conjunctival scars, meibomitis) was tested by means of the ‘Rolando-Refojo tear evaporimeter’, which allows noninvasive and reproducible test conditions. These eyes show a statistically significant increase in tear evaporation rate compared to normal eyes. The clinical implications of this finding are discussed.

Maurizio Rolando; Miguel F. Refojo; Kenneth R. Kenyon

1985-01-01

121

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

122

The Pan-STARRS Moving Object Processing System  

E-print Network

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 non-physical 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 >99.5% efficient at detecting objects on a single night but drops to 80% efficiency at producing orbits for objects detected on multiple nights. This loss is primarily due to co...

Denneau, Larry; Grav, Tommy; Granvik, Mikael; Kubica, Jeremy; Milani, Andrea; Veres, 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

2013-01-01

123

The Imager for Mars Pathfinder Insurance Pan  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

124

Nanofluid Drop Evaporation: Experiment, Theory, and Modeling  

NASA Astrophysics Data System (ADS)

Nanofluids, stable colloidal suspensions of nanoparticles in a base fluid, have potential applications in the heat transfer, combustion and propulsion, manufacturing, and medical fields. Experiments were conducted to determine the evaporation rate of room temperature, millimeter-sized pendant drops of ethanol laden with varying amounts (0-3% by weight) of 40-60 nm aluminum nanoparticles (nAl). Time-resolved high-resolution drop images were collected for the determination of early-time evaporation rate (D2/D 02 > 0.75), shown to exhibit D-square law behavior, and surface tension. Results show an asymptotic decrease in pendant drop evaporation rate with increasing nAl loading. The evaporation rate decreases by approximately 15% at around 1% to 3% nAl loading relative to the evaporation rate of pure ethanol. Surface tension was observed to be unaffected by nAl loading up to 3% by weight. A model was developed to describe the evaporation of the nanofluid pendant drops based on D-square law analysis for the gas domain and a description of the reduction in liquid fraction available for evaporation due to nanoparticle agglomerate packing near the evaporating drop surface. Model predictions are in relatively good agreement with experiment, within a few percent of measured nanofluid pendant drop evaporation rate. The evaporation of pinned nanofluid sessile drops was also considered via modeling. It was found that the same mechanism for nanofluid evaporation rate reduction used to explain pendant drops could be used for sessile drops. That mechanism is a reduction in evaporation rate due to a reduction in available ethanol for evaporation at the drop surface caused by the packing of nanoparticle agglomerates near the drop surface. Comparisons of the present modeling predictions with sessile drop evaporation rate measurements reported for nAl/ethanol nanofluids by Sefiane and Bennacer [11] are in fairly good agreement. Portions of this abstract previously appeared as: W. J. Gerken, A. V. Thomas, N. Koratkar and M. A. Oehlschlaeger, Int. J. Heat Mass Transfer, vol. 74, no. 1, pp. 263-268, July 2014. W. J. Gerken, M. A. Oehlschlaeger, "Nanofluid Pendant Droplet Evaporation", in Proceedings of the ASME 2013 Summer Heat Transfer Conference, Minneapolis, MN, 2013, pp. V001T03A018.

Gerken, William James

125

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

Federal Register 2010, 2011, 2012, 2013, 2014

...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

126

Mapping the Amazon: Mosaic pan  

NSDL National Science Digital Library

Pan across Amazon rainforest mosaic showing low water season (blue) and high water season (yellow). Together, these snapshots reveal conditions on the ground. Scientists listed worked as a team on Mosaicking Software and Mosaic Production.

Stuart Snodgrass

2002-03-14

127

Relationships between PAN and ozone at sites in eastern North America  

NASA Astrophysics Data System (ADS)

Measurements of ozone and PAN (peroxyacetic nitric anhydride) were made at four sites in eastern North America; Bondville, Illinois, Egbert, Ontario, Scotia, Pennsylvania, and Whitetop Mountain, Virginia., in July and August of 1988 as part of a study of regional oxidant photochemistry. The concentrations of PAN ranged from <0.010 to 9.2 parts-per-billion by volume (ppbv) and those of O3 ranged from <2 to 139 ppbv. Diurnal concentration profiles showed PAN and O3 to be removed within nocturnal boundary layers, especially if nitric oxide was present, and that O3 was, for most sites, more rapidly removed than PAN. The only mountain top site at which PAN was measured showed distinctly different diurnal profiles in which O3 was actually higher at night, suggesting that convective flow driven by surface cooling served to transport air down from higher in the mixed layer at night. The afternoon production of PAN and O3 was also apparent and led to an overall linear correlation of O3 and PAN between the hours of 1300 and 1800. The comparison of this result with other measurements, estimates of PAN formation rates, and model calculations indicates that the production of PAN relative to ozone is far greater (x3) than can be accounted for by acetaldehyde reactions with OH, there is a wide disparity in model descriptions of PAN production, and confirms the non-linear dependence of O3 production on NOx.

Roberts, J. M.; Tanner, R. L.; Newman, L.; Bowersox, V. C.; Bottenheim, J. W.; Anlauf, K. G.; Brice, K. A.; Parrish, D. D.; Fehsenfeld, F. C.; Buhr, M. P.; Meagher, J. F.; Bailey, E. M.

1995-11-01

128

Evaporation Induced Isothermal Crystallization of Silicate Melt  

NASA Astrophysics Data System (ADS)

In order to investigate and role of evaporation and crystallization kinetics for silicate melt, isothermal vacuum experiments were carried out in the system MgO-SiO2. Due to successive evaporation, melt crystallized olivine at a fixed temperature. The evaporation rates and bulk chemical composition of residues varied with time, and reached a steady state. The pressure-composition phase diagram for the system at a fixed temperature well explains the experimental results. The results suggest a possibility of isothermal formation of chondrules (and some CAIs) at low pressures where evaporation takes place continuously.

Nagahara, H.

1996-03-01

129

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.

Amy Townsend-Small

130

Development of PAN-based absorbers for treating waste problems at U.S. DOE facilities  

SciTech Connect

Polyacrylonitrile (PAN) can be used to bind together very small particles of absorbers into porous aggregates that can be used conveniently in packed columns. While binding the small particles together, the PAN allows substantial diffusion and even flow through the aggregates to give high effective mass transfer rates. Although PAN has been used or proposed for several applications, its capabilities for use with the US Department of Energy (DOE) radioactive wastes have not been determined. This paper summaries studies at the Czech Technical University on the stability of PAN-based absorbers under the radiation, chemical, and physical conditions needed for DOE wastes and assessments of their potential performance with selected US wastes.

Sebesta, F.; John, J.; Motl, A. [Czech Technical Univ., Prague (Czech Republic). Dept. of Nuclear Chemistry; Watson, J.S. [Oak Ridge National Lab., TN (United States)

1995-12-31

131

PanSNPdb: the Pan-Asian SNP genotyping database.  

PubMed

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

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

2011-01-01

132

Inhibiting ventilatory evaporation produces an adaptive increase in cutaneous evaporation in mourning doves Zenaida macroura.  

PubMed

We tested the hypothesis that birds can rapidly change the conductance of water vapor at the skin surface in response to a changing need for evaporative heat loss. Mourning doves (Zenaida macroura) were placed in a two-compartment chamber separating the head from the rest of the body. The rate of cutaneous evaporation was measured in response to dry ventilatory inflow at three ambient temperatures and in response to vapor-saturated ventilatory inflow at two ambient temperatures. At 35 degrees C, cutaneous evaporation increased by 72 % when evaporative water loss from the mouth was prevented, but no increase was observed at 45 degrees C. For both dry and vapor-saturated treatments, cutaneous evaporation increased significantly with increased ambient temperature. Changes in skin temperature made only a minor contribution to any observed increase in cutaneous evaporation. This indicates that Z. macroura can effect rapid adjustment of evaporative conductance at the skin in response to acute change in thermoregulatory demand. PMID:10518483

Hoffman; Walsberg

1999-01-01

133

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

134

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

135

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. PMID:19861551

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

2009-01-01

136

On the evaporation of ammonium sulfate solution  

SciTech Connect

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

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

2009-07-16

137

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

138

An electronic pan/tilt/zoom camera system  

NASA Technical Reports Server (NTRS)

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

Zimmermann, Steve; Martin, H. L.

1992-01-01

139

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

140

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

141

Dynamics of evaporative colloidal patterning  

E-print Network

Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying colloidal solution. Direct observations allow us to visualize the dynamics of the band and film deposition, and the transition in between when the colloidal concentration is varied. A minimal theory of the liquid meniscus motion along the plate reveals the dynamics of the banding and its transition to the filming as a function of the ratio of deposition and evaporation rates. We also provide a complementary multiphase model of colloids dissolved in the liquid, which couples the inhomogeneous evaporation at the evolving meniscus to the fluid and particulate flows and the transition from a dilute suspension to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the deposition rate. Together, our findings allow for the control of drying-induced patterning as a function of the colloidal concentration and evaporation rate.

C. Nadir Kaplan; Ning Wu; Shreyas Mandre; Joanna Aizenberg; L. Mahadevan

2014-12-04

142

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

143

Helicity transfer in rotary evaporator flow  

NASA Astrophysics Data System (ADS)

Mechanical rotation of a magnetic stirrer or a rotary evaporator can induce an enantiomeric excess of supramolecular species. In this study, we investigate the effect of fluid motion in a rotary evaporator on chiral supramolecular species. It is shown theoretically that the twisting effect of fluid motion on cylindrical particles is expressed in terms of helicity dissipation rate. Helicity dissipation can be interpreted as the helicity transfer from helical fluid motion to chiral supramolecular structures. A numerical simulation of flow in a rotary evaporator was carried out to evaluate the helicity and its dissipation rate. The volume integral of the helicity dissipation in the computational domain showed a positive value; its sign agrees with experiment in which the right-handed helical structures of J-aggregates were induced by the counter-clockwise rotation of a rotary evaporator. Furthermore, terms in the transport equation for the helicity were evaluated for investigating the helicity behavior.

Hamba, Fujihiro; Niimura, Kazuhiro; Kitagawa, Yuichi; Ishii, Kazuyuki

2014-01-01

144

Evaporative Deposition in Receding Drops  

E-print Network

We present a framework for calculating the surface density profile of a stain deposited by a drop with a receding contact line. Unlike a pinned drop, a receding drop pushes fluid towards its interior, continuously deposits mass across its substrate as it evaporates, and does not produce the usual "coffee ring." For a thin, circular drop with a constant evaporation rate, we find the surface density of the stain goes as $\\eta(r) \\propto \\left(\\left(r/a_0\\right)^{-1/2}-r/a_0\\right)$, where $r$ is the radius from the drop center and $a_0$ is the initial outer radius. Under these conditions, the deposited stain has a mountain-like morphology. Our framework can easily be extended to investigate new stain morphologies left by drying drops.

Julian Freed-Brown

2014-10-09

145

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

146

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 ...

Miss Brown

2009-10-21

147

Flash evaporator systems test  

NASA Technical Reports Server (NTRS)

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

Dietz, J. B.

1976-01-01

148

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

149

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

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

150

CAPSULE REPORT: EVAPORATION PROCESS  

EPA Science Inventory

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

151

Metallurgical and acoustical comparisons for a brass pan with a Caribbean steel pan standard  

Microsoft Academic Search

The development and fabrication of a-brass pans, including the sinking of the pan head in the traditional manner using a hammer and patterning musical notes and their turning is compared with a low-carbon steel (Caribbean-type) pan as a standard. In this study these experimental pans are fabricated by welding the a-brass or low-carbon steel platforms to a low-carbon steel hoop

L. E. Murr; E. V. Esquivel; A. A. Bujanda; N. E. Martinez; K. F. Soto; A. S. Tapia; S. Lair; A. C. Somasekharan; C. A. C. Imbert; R. Kerns; S. Irvine; S. Lawrie

2004-01-01

152

Visualization of an evaporating thin layer during the evaporation of a nanofluid droplet.  

PubMed

During the evaporation of a droplet, there exists an evaporating thin layer that is difficult to visualize because of optical restrictions. The present study visualized this thin layer by using a reflective-mode, confocal microscope that can provide improved signal-to-noise focal plane imaging over traditional optical microscopy while simultaneously serving as an interferometer when imaging thin liquid films. The spatial distribution of the evaporating thin layer thickness was determined from interferometric fringe analysis. Three distinct fringe patterns, or regions, were observed depending on the nanoparticle concentration. These regions are referred to as uniform, slow extension, and rapid extension. The formation of the three regions is closely associated with the variation of the evaporating thin layer thickness of a nanofluid droplet. The nanoparticle bank formed near the contact line region substantially affects the rate of change in the evaporating thin layer thickness that increases with the nanoparticle concentration. PMID:25586137

Shin, Dong Hwan; Allen, Jeffrey S; Choi, Chang Kyoung; Lee, Seong Hyuk

2015-02-01

153

Study of environmental isotope distribution in the Aswan High Dam Lake (Egypt) for estimation of evaporation of lake water and its recharge to adjacent groundwater.  

PubMed

Oxygen-18 ((18)0) and deuterium isotopes were used to estimate the evaporation from the Aswan High Dam Lake and to investigate the inter-relation between the lake water and adjacent groundwater.According to stable isotopic analysis of samples taken in 1988 and 1989, the lake can be divided into two sections. In the first section extending between Abu Simbel and a point between EI-Alaki and Krosko, a remarkable vertical gradient of (18)0 and deuterium isotopic composition was observed. The second northern sector extending to the High Dam is characterised by a lower vertical isotopic gradient. In this sector in general, higher values of (18)O and deuterium contents were found at the top and lower values at the bottom. Also a strong horizontal increase of the heavy isotope content was observed. Thus, in the northern section evaporation is of dominating influence on the isotopic composition of the lake water.With the help of an evaporation pan experiment it was possible to calibrate the evaporative isotope enrichment in the lake and to facilitate a preliminary estimate of evaporative losses of lake water. The evaporation from the lake was estimated to be about 19% of the input water flow rate.The groundwater around the lake was investigated and samples from production wells and piezometers were subjected to isotopic analysis. The results indicate that recent recharge to the groundwater aquifer is limited to wells near to the lake and up to a maximum distance of about 10 km. The contribution of recent Nile water to the groundwater in these wells was estimated to range between 23 and 70%. Beyond this distance, palaeowater was observed with highly depleted deuterium and (18)0 contents, which was also confirmed by 14c dating. The age of palaeo groundwater in this area can reach values of more than 26,000 years.Recommendations are given for efficient water management of the lake water. PMID:24198080

Aly, A I; Froehlich, K; Nada, A; Awad, M; Hamza, M; Salem, W M

1993-03-01

154

Sheet Membrane Spacesuit Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

155

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

156

Measure Guideline: Evaporative Condensers  

SciTech Connect

The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

German, A.; Dakin, B.; Hoeschele, M.

2012-03-01

157

Turbulent Sprays Evaporating Under  

Microsoft Academic Search

An “in-house” computational fluid dynamics code implementing a Euler-Lagrange approach is extended by incorporating the Euler-Euler (two-fluid model) approach, to improve prediction capabilities of flow and thermal characteristics of turbulent evaporating sprays. The performance of both approaches is assessed by comparing predictions with experimental data for a variety of evaporating-spray test cases. The applicability of the Euler-Lagrange and Euler-Euler approach

Maria A. Founti; Dimitrios I. Katsourinis; Dionysios I. Kolaitis

2007-01-01

158

Effects of Evaporation and Thermocapillary Convection on Spreading and Contact Angle of Volatile Liquid Droplets  

NASA Technical Reports Server (NTRS)

Results of an experimental investigation of evaporating sessile drops on a glass-slide surface for three volatile liquids show that both evaporation and thermocapillary convection in the sessile drop strongly affect the drop spreading and contact angle. The evolution of contact diameter of the drops can be divided into four stages: (1) initial spreading; (2) spreading-evaporation balance; (3) evaporation-dominating contraction; and (4) final rapid contraction. Molecular-kinetic spreading always occurs in the early first stage and is rapidly restrained and then taken over by the effects of evaporation. Thermocapillary convection, induced by the evaporation, promotes the competition of evaporation over the spreading and shortens the spreading-evaporation balance stage to become undetectable. Evaporation may increase or decrease the contact angle of the evaporating sessile drops, depending on the evaporation rate.

Chao, David F.; Zhang, Nengli

2000-01-01

159

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

NASA Technical Reports Server (NTRS)

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

Seshadri, K.; Rosner, D. E.

1985-01-01

160

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

161

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

PubMed

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

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

2013-12-01

162

An automated tunnel evaporation measurement system for confined spaces  

NASA Astrophysics Data System (ADS)

An automated tunnel evaporation-rate measurement system (TEMS) has been designed to measure automatically the evaporation from a cylinder 0·30 m in diameter and 0·10 m tall. This cylinder continuously maintains a constant height of water, with losses to evaporation replenished from a stilling cylinder connected to a water reservoir. The evaporation rate is measured by a transducer located at the bottom of the stilling well. The TEMS was tested over a period of 3 months in an underground research facility with relatively strong wind effects, changing temperature, and changing humidity. During this period, the TEMS continued to function uninterrupted, automatically measuring the evaporation amounts along a tunnel and an enclosed niche. These observations suggest that this tool can be useful for investigations of evaporation processes both in enclosed and ventilated environments. Published in 2002 by John Wiley & Sons, Ltd.

Salve, Rohit

2002-04-01

163

Disruption of tillage pans by slot tillage  

Technology Transfer Automated Retrieval System (TEKTRAN)

In some areas of the central Great Plains, traditional sweep tillage for weed control has led to a root-restrictive tillage pan approximately 10 to 15 cm beneath the soil surface. Producers have shown interest in methods to disrupt this tillage pan prior to transitioning to no-till soil management. ...

164

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±0.46 ppb, respectively. The seasonal trends of PAN generally exhibited dual peaks in both early spring and fall, regardless of sites. Their diurnal trends were fairly comparable to each other. There was a slight time lag (e.g., 1 h) in the peak occurrence pattern between O3 and PAN, as the latter trended to peak after the maximum UV irradiance period (16:00 (GJ) and 17:00 (GS)). The concentrations of PAN generally exhibited strong correlations with particulates. The results of this study suggest that PAN concentrations were affected sensitively by atmospheric stability, the wet deposition of NO2, wind direction, and other factors. PMID:23838043

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

2013-11-01

165

Combined Evaporation and Salt Precipitation in Porous Media  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

166

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

SciTech Connect

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 isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tank toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.

Tamburello, D; Richard Dimenna, R; Si Lee, S

2009-01-27

167

Dry deposition of pan to grassland vegetation  

SciTech Connect

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 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 process is slow. Measurements of the uptake of PAN by alfalfa in growth chambers indicated that the dry deposition velocity (downward flux divided by concentration at a specified height) was 0.75 cm s{sup {minus}1}. Garland and Penkett measured a dry deposition velocity of 0.25 cm s{sup {minus}1} for PAN to grass and soil in a return-flow wind tunnel. Shepson et al. (1992) analyzed trends of PAN and O{sub 3} concentrations in the stable nocturnal boundary layer over mixed deciduous/coniferous forests at night, when leaf stomata were closed, and concluded that the deposition velocity for PAN was at least 0.5 cm s{sup {minus}1}. We measured the dry deposition velocity of PAN to a grassland site in the midwestern United States with a modified Bowen ratio technique. Experiments were conducted on selected days during September, October, and November of 1990. An energy balance Bowen ratio station was used to observe the differences in air temperature and water vapor content between heights of 3.0 and 0.92 m and to evaluate the surface energy balance. Air samples collected at the same two heights in Teflon {reg_sign} bags were analyzed for PAN by a gas chromatographic technique. We present an example of the variations of PAN concentrations and gradients observed during the day and compare measurements of the dry deposition velocity to expectations based on the physicochemical properties of PAN.

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

1994-01-01

168

Structuring of polymer solutions upon solvent evaporation  

NASA Astrophysics Data System (ADS)

The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench involving immiscible blends, the spinodal instability initially develops slowly and the associated length scale is not time invariant but decreases with time as t-1 /2. After a time lag, phase separation accelerates. Time lag and characteristic length exhibit power-law behavior as a function of the evaporation rate with exponents of -2 /3 and -1 /6 . Interestingly, at later stages the spinodal structure disappears completely while a second length scale develops. The associated structure coarsens but does not follow the usual Lifshitz-Slyozov-Wagner kinetics.

Schaefer, C.; van der Schoot, P.; Michels, J. J.

2015-02-01

169

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

170

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

171

Panning for Gold and Magnetite  

NSDL National Science Digital Library

In this activity, students can learn to pan for gold and magnetite. They will learn skills such as making observations under field conditions and watching out for poison ivy. They will see the effects of stream flow on sediments and observe sedimentary structures such as stream bars and islands, observe that different sizes of sediment are located in different parts of the stream, distinguish between different sizes of sediment, and recognize that different minerals are different colors. In addition, they can estimate and weigh the content of magnetite and nonmagnetite, observe crystal shapes of some of the mineral grains, and discuss why magnets pick up magnetite but not nonmagnetic grains. Choose desired title from main listing of activities to access individual exercises.

Eleanora Robbins

172

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

173

An investigation of electrochemomechanical actuation of conductive Polyacrylonitrile (PAN) nanofiber composites  

NASA Astrophysics Data System (ADS)

A polymer-based nanofiber composite actuator designed for contractile actuation was fabricated by electrospinning, stimulated by electrolysis, and characterized by electrochemical and mechanical testing to address performance limitations and understand the activation processing effects on actuation performance. Currently, Electroactive polymers (EAPs) have provided uses in sensory and actuation technology, but have either low force output or expand rather than contract, falling short in capturing the natural kinetics and mechanics of muscle needed to provide breakthroughs in the bio-medical and robotic fields. In this study, activated Polyacrylonitrile (PAN) fibers have demonstrated biomimetic functionalities similar to the sarcomere contraction responsible for muscle function. Activated PAN has also been shown to contract and expand by electrolysis when in close vicinity to the anode and cathode, respectively. PAN nanofibers (~500 nm) especially show faster response to changes in environmental pH and improved mechanical properties compared to larger diameter fibers. Tensile testing was conducted to examine changes in mechanical properties between annealing and hydrolysis processing. Voltage driven transient effects of localized pH were examined to address pHdefined actuation thresholds of PAN fibers. Electrochemical contraction rates of the PAN/Graphite composite actuator demonstrated up to 25%/min. Strains of 58.8%, ultimate stresses up to 77.1 MPa, and moduli of 0.21 MPa were achieved with pure PAN nanofiber mats, surpassing mechanical properties of natural muscles. Further improvements, however, to contraction rates and Young's moduli were found essential to capture the function and performance of skeletal muscles appropriately.

Gonzalez, Mark A.; Walter, Wayne W.

2014-03-01

174

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

NASA Astrophysics Data System (ADS)

Characterizing hydrological processes within tropical wetlands is challenging due to their remoteness, complexity and heterogeneity. In particular, estimates of evaporative water loss are inherently uncertain. In view of the large influence on the local and regional climate, the quantification of evaporation is essential for the determination of the water balance of permanent and intermittent water bodies. Data for tropical wetlands are scarce where their remoteness impedes direct evaporation measurements. Seasonal inundation dynamics affect evaporation processes in tropical wetlands, which can be analysed in two stages: the first stage during the wet season and the second stage during the dry season. As yet no adequate method exists for determining second-stage evaporation in a data-scarce environment that additionally allows for a transfer of simulated actual evaporation (AET) to other locations. Our study aimed at developing a process-based model to simulate first- and second-stage evaporation in tropical wetlands. We selected a set of empirical potential evaporation (PET) models of varying complexity, each based on different assumptions and available data sets, and evaluated the models with pan evaporation observations in the Pantanal of South America, one of the largest tropical wetlands in the world. We used high-resolution measurements of surface and groundwater levels at different locations to determine the water available for evaporation. AET was derived by constraining simulated PET based on available water. The model of best fit was applied to different types of water bodies with varying hydroperiods to capture first- and second-stage evaporation across a range of wetland types. With our new model we could quantify evaporative water loss in the dry and the wet season for different locations in the Pantanal. This new spatially explicit approach represents an improvement in our understanding of the role of evaporation in the water balance of the Pantanal. We recommend the application of this model in other remote tropical wetlands, since only a minimum of input data is necessary.

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

2014-11-01

175

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

176

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, A.M., Jr.; Mau, D.P.

2003-01-01

177

Early science from the Pan-STARRS1 Optical Galaxy Survey (POGS): Maps of stellar mass and star formation rate surface density obtained from distributed-computing pixel-SED fitting  

NASA Astrophysics Data System (ADS)

To measure resolved galactic physical properties unbiased by the mask of recent star formation and dust features, we are conducting a citizen-scientist enabled nearby galaxy survey based on the unprecedented optical (g,r,i,z,y) imaging from Pan-STARRS1 (PS1). The PS1 Optical Galaxy Survey (POGS) covers 3? steradians (75% of the sky), about twice the footprint of SDSS. Whenever possible we also incorporate ancillary multi-wavelength image data from the ultraviolet (GALEX) and infrared (WISE, Spitzer) spectral regimes. For each cataloged nearby galaxy with a reliable redshift estimate of z < 0.05 - 0.1 (dependent on donated CPU power), publicly-distributed computing is being harnessed to enable pixel-by-pixel spectral energy distribution (SED) fitting, which in turn provides maps of key physical parameters such as the local stellar mass surface density, crude star formation history, and dust attenuation. With pixel SED fitting output we will then constrain parametric models of galaxy structure in a more meaningful way than ordinarily achieved. In particular, we will fit multi-component (e.g. bulge, bar, disk) galaxy models directly to the distribution of stellar mass rather than surface brightness in a single band, which is often locally biased. We will also compute non-parametric measures of morphology such as concentration, asymmetry using the POGS stellar mass and SFR surface density images. We anticipate studying how galactic substructures evolve by comparing our results with simulations and against more distant imaging surveys, some of which which will also be processed in the POGS pipeline. The reliance of our survey on citizen-scientist volunteers provides a world-wide opportunity for education. We developed an interactive interface which highlights the science being produced by each volunteer’s own CPU cycles. The POGS project has already proven popular amongst the public, attracting about 5000 volunteers with nearly 12,000 participating computers, and is growing rapidly.

Thilker, David A.; Vinsen, K.; Galaxy Properties Key Project, PS1

2014-01-01

178

Temperature field beneath evaporating surface resolved by infrared thermography  

NASA Astrophysics Data System (ADS)

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

Shahraeeni, Ebrahim; Or, Dani

2010-05-01

179

Evaporation-induced self-assembled silica colloidal particle-assisted nanoporous structural evolution of poly(ethylene terephthalate) nonwoven composite separators for high-safety/high-rate lithium-ion batteries  

NASA Astrophysics Data System (ADS)

A facile approach to the fabrication of nanoporous structure-tuned nonwoven composite separators is demonstrated for application in high-safety/high-rate lithium-ion batteries. This strategy is based on the construction of silica (SiO2) colloidal particle-assisted nanoporous structure in a poly(ethylene terephthalate) (PET) nonwoven substrate. The nanoparticle arrangement arising from evaporation-induced self-assembly of SiO2 colloidal particles allows the evolution of the unusual nanoporous structure, i.e. well-connected interstitial voids formed between close-packed SiO2 particles adhered by styrene-butadiene rubber (SBR) binders. Meanwhile, the PET nonwoven serves as a mechanical support that contributes to suppressing thermal shrinkage of the nonwoven composite separator. The aforementioned structural novelty of the nonwoven composite separator plays a key role in providing the separator with advantageous characteristics (specifically, good electrolyte wettability, high ionic conductivity, and benign compatibility with electrodes), which leads to the better cell performance than a commercialized polyethylene (PE) separator.

Lee, Jung-Ran; Won, Ji-Hye; Kim, Jong Hun; Kim, Ki Jae; Lee, Sang-Young

2012-10-01

180

Evaporative cooling of antiprotons for the production of trappable antihydrogen  

SciTech Connect

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

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

2013-03-19

181

EFFECT OF FRACTIONAL CRYSTALLIZATION ON 25 MG OF EVAPORATION  

E-print Network

EFFECT OF FRACTIONAL CRYSTALLIZATION ON 25 MG OF EVAPORATION RESIDUES OF CMAS LIQUIDS. A. V. FedkinO-MgO-Al2O3-SiO2 (CMAS) liquids during simultaneous crystallization and evaporation was studied to fractional crystallization. In this work, the effects of ambient total pressure and cooling rate

Grossman, Lawrence

182

Experimental study on water evaporation from sand using environmental chamber  

E-print Network

and various drying durations were imposed on the soil sample. Atmospheric parameters (air flow rate, relative. The results show that the air and soil temperatures depend on the evaporation process and atmospheric Fontainebleau, succion a` la surface du sol. Introduction Soil water evaporation at the air­soil interface

Paris-Sud XI, Université de

183

Preferential Evaporation From Heterogeneous Porous Media With Vertical Textural Contrasts  

Microsoft Academic Search

High evaporative drying rates of porous media are typically sustained by capillary water flow to vaporization plane from wet zones below (stage-1 evaporation). The extent of the hydraulically connected region depends on width of the pore size distribution and the interplay between capillarity, gravity and viscous forces. In heterogeneous soils the effective range of hydraulically-connected pore sizes may be enhanced

D. Or; P. Lehmann; N. Shokri; E. Shahraeeni

2008-01-01

184

Physiological adjustments of sand gazelles (Gazella subgutturosa) to a boom-or-bust economy: standard fasting metabolic rate, total evaporative water loss, and changes in the sizes of organs during food and water restriction.  

PubMed

To test the hypothesis that desert ungulates adjust their physiology in response to long-term food and water restriction, we established three groups of sand gazelles (Gazella subgutturosa): one that was provided food and water (n = 6; CTRL) ad lib. for 4 mo, one that received ad lib. food and water for the same period but was deprived of food and water for the last 4.5 d (n = 6; EXPT(1)), and one that was exposed to 4 mo of progressive food and water restriction, an experimental regime designed to mimic conditions in a natural desert setting (n = 6; EXPT(2)). At the end of the 4-mo experiment, we measured standard fasting metabolic rate (SFMR) and total evaporative water loss (TEWL) of all sand gazelles and determined lean dry mass of organs of gazelles in CTRL and EXPT(2). Gazelles in CTRL had a mean SFMR of 2,524 +/- 194 kJ d(-1), whereas gazelles in EXPT(1) and EXPT(2) had SFMRs of 2,101+/- 232 and 1,365 +/- 182 kJ d(-1), respectively, values that differed significantly when we controlled for differences in body mass. Gazelles had TEWLs of 151.1 +/- 18.2, 138.5 +/- 17.53, and 98.4 +/- 27.2 g H(2)O d(-1) in CTRL, EXPT(1), and EXPT(2), respectively. For the latter group, mass-independent TEWL was 27.1% of the value for CTRL. We found that normally hydrated sand gazelles had a low mass-adjusted TEWL compared with other arid-zone ungulates: 13.6 g H(2)O kg(-0.898) d(-1), only 17.1% of allometric predictions, the lowest ever measured in an arid-zone ungulate. After 4 mo of progressive food and water restriction, dry lean mass of liver, heart, and muscle of gazelles in EXPT(2) was significantly less than that of these same organs in CTRL, even when we controlled for body mass decrease. Decreases in the dry lean mass of liver explained 70.4% of the variance of SFMR in food- and water-restricted gazelles. As oxygen demands decreased because of reduced organ sizes, gazelles lost less evaporative water, probably because of a decreased respiratory water loss. PMID:16826507

Ostrowski, Stephane; Mesochina, Pascal; Williams, Joseph B

2006-01-01

185

Evaporation of stationary alcohol layer in minichannel under air flow  

NASA Astrophysics Data System (ADS)

This paper presents experimental investigation of effect of the gas flow rate moving parallel to the stationary liquid layer on the evaporation rate under the conditions of formation of a stable plane "liquid-gas" interface. The average evaporation flow rate of liquid layer (ethanol) by the gas flow (air) has been calculated using two independent methods. Obtained results have been compared with previously published data.

Afanasyev, Ilya; Orlova, Evgenija; Feoktistov, Dmitriy

2015-01-01

186

Comparison of steady-state evaporation models for toxic chemical spills: Development of a new evaporation model. Environmental research papers  

Microsoft Academic Search

The United States Air Force handles and stores a number of toxic and hazardous chemicals. Associated with this activity is the threat of accidental release. To determine the downwind threat of a spilled liquid chemical, one must estimate the evaporation rate of the spilled chemical. A steady state evaporation model is one that calculates the temperature of the spilled chemical

Vossler

1989-01-01

187

Disk-Evaporation Fed Corona: Structure and Evaporation Feature with Magnetic Field  

E-print Network

The disk-corona evaporation model naturally interprets many observational phenomena in black hole X-ray binaries, such as the truncation of an accretion disk and the spectral state transitions. On the other hand, magnetic field is known to play an important role in transporting angular momentum and producing viscosity in accretion flows. In this work, we explicitly take the magnetic field in the accretion disk corona into account and numerically calculate the coronal structure on the basis of our two-temperature evaporation code. We show that the magnetic field influences the coronal structure by its contribution to the pressure, energy and radiative cooling in the corona and by decreasing the vertical heat conduction. We found that the maximal evaporation rate keeps more or less constant ($\\sim 0.03$ Eddington rate) while the strength of magnetic fields changes, but that the radius corresponding to the maximal evaporation rate decreases with increasing magnetic field. This predicts that the spectral state transition always occurs at a few percent of Eddington accretion rate, while the inner edge of thin disk can be at $\\sim 100 R_{\\rm S} $ or even less in the hard state before the transition to the soft state. These results alleviate the problem that previous evaporation models predict too large a truncation radius, and are in better agreement with the observational results of several black hole X-ray binaries, though discrepancies remain.

Lei Qian; B. F. Liu; Xue-Bing Wu

2007-07-03

188

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

189

Bubble vortex at surfaces of evaporating liquids.  

PubMed

Air bubble in volatile liquid on exiting to the surface spins a vortex maintaining integrity of the film over an indefinite period of time. The shear stress associated with the surface tension increase in the adiabatic evaporation cooling drags the warmer liquid inwards into the film counteracting its capillary drainage out under gravity. The chaotic patterns, visualized with the aid of light interferometry, depend on liquid volatility, degree of vapor saturation, and air convection. The circulation intensifies and the frequency of hydrodynamic instabilities in the multiphase flow increases on the transition to strong turbulent regimes with increasing evaporation rate. Self-consistency of the physical mechanisms of solute and evaporation inhibition of bubble coalescence is verified through dimensional parametric analysis. PMID:16297397

Yaminsky, V V

2006-05-01

190

Formation and Evaporation of Charged Black Holes  

E-print Network

We investigate the dynamical formation and evaporation of a spherically symmetric charged black hole. We study the self-consistent one loop order semiclassical back-reaction problem. To this end the mass-evaporation is modeled by an expectation value of the stress-energy tensor of a neutral massless scalar field, while the charge is not radiated away. We observe the formation of an initially non extremal black hole which tends toward the extremal black hole $M=Q$, emitting Hawking radiation. If also the discharge due to the instability of vacuum to pair creation in strong electric fields occurs, then the black hole discharges and evaporates simultaneously and decays regularly until the scale where the semiclassical approximation breaks down. We calculate the rates of the mass and the charge loss and estimate the life-time of the decaying black holes.

Evgeny Sorkin; Tsvi Piran

2001-03-25

191

Evaporation of Two Dimensional Black Holes  

E-print Network

Callan, Giddings, Harvey and Strominger have proposed an interesting two dimensional model theory that allows one to consider black hole evaporation in the semi-classical approximation. They originally hoped the black hole would evaporate completely without a singularity. However, it has been shown that the semi-classical equations will give a singularity where the dilaton field reaches a certain critical value. Initially, it seems this singularity will be hidden inside a black hole. However, as the evaporation proceeds, the dilaton field on the horizon will approach the critical value but the temperature and rate of emission will remain finite. These results indicate either that there is a naked singularity, or (more likely) that the semi-classical approximation breaks down when the dilaton field approaches the critical value.

S. W. Hawking

1992-03-18

192

An electronic pan/tilt/zoom camera system  

NASA Technical Reports Server (NTRS)

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

Zimmermann, Steve; Martin, H. Lee

1991-01-01

193

The Pan-STARRS Large Survey Telescope Project  

NASA Astrophysics Data System (ADS)

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. The Pan-STARRS project is funded by the US Air Force and will consist of an array of four 1.8m telescopes with very large (7 square degree) field of view, giving it an etendue larger than all existing survey instruments combined. Each telescope will be equipped with a 1.4 billion pixel CCD camera with low noise and rapid read-out, and the data will be reduced in near real time to produce both cumulative static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to scan the entire visible sky to a detection limit of approximately 24th magnitude in less than a week. This unique combination of sensitivity and cadence will dramatically increase the discovery rate for moving objects and will thereby enable a wide range of solar system science goals. In particular, a major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. A single telescope system will be deployed on Haleakala, with first light early in 2006, and the full 4 telescope system will become operational towards the end of the decade.

Kaiser, N.; Pan-STARRS Project Team

2005-08-01

194

3 CFR 8361 - Proclamation 8361 of April 14, 2009. Pan American Day and Pan American Week, 2009  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Proclamation 8361 of April 14, 2009. Pan American Day and Pan American... Proclamations Proclamation 8361 of April 14, 2009 Proc. 8361 Pan American...the United States, do hereby proclaim April 14, 2009, as Pan American Day and...

2010-01-01

195

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

PubMed

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

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

2014-07-17

196

Pan-information Location Map  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

197

The Pan-STARRS discovery machine  

NASA Astrophysics Data System (ADS)

The Pan-STARRS System has proven to be a remarkable machine for discovery. The PS1 Science Mission has drawn to a close, and the second Pan-STARRS survey, optimized for NEO's has begun. PS2 is in the commissioning stages and will eventually support NEO discovery as well. The performance of the PS1 system, sky coverage, cadence, and data quality of the Pan-STARRS1 Surveys will be presented as well as progress in reprocessing of the data taken to date and the plans for the public release of all Pan-STARRS1 data products in the spring of 2015. Science results related to planetary studies and the dust will be presented. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE).

Chambers, Kenneth C.

2014-11-01

198

Vertical counterflow evaporative cooler  

DOEpatents

An evaporative heat exchanger having parallel plates that define alternating dry and wet passages. A water reservoir is located below the plates and is connected to a water distribution system. Water from the water distribution system flows through the wet passages and wets the surfaces of the plates that form the wet passages. Air flows through the dry passages, mixes with air below the plates, and flows into the wet passages before exiting through the top of the wet passages.

Bourne, Richard C.; Lee, Brian Eric; Callaway, Duncan

2005-01-25

199

An indirect evaporative chiller  

Microsoft Academic Search

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

Xiaoyun Xie; Yi Jiang

2010-01-01

200

Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

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

Ungar, Eugene K.; Almlie, Jay C.

2010-01-01

201

Monthly evaporation forecasting using artificial neural networks and support vector machines  

NASA Astrophysics Data System (ADS)

Evaporation is one of the most important components of the hydrological cycle, but is relatively difficult to estimate, due to its complexity, as it can be influenced by numerous factors. Estimation of evaporation is important for the design of reservoirs, especially in arid and semi-arid areas. Artificial neural network methods and support vector machines (SVM) are frequently utilized to estimate evaporation and other hydrological variables. In this study, usability of artificial neural networks (ANNs) (multilayer perceptron (MLP) and radial basis function network (RBFN)) and ?-support vector regression (SVR) artificial intelligence methods was investigated to estimate monthly pan evaporation. For this aim, temperature, relative humidity, wind speed, and precipitation data for the period 1972 to 2005 from Beysehir meteorology station were used as input variables while pan evaporation values were used as output. The Romanenko and Meyer method was also considered for the comparison. The results were compared with observed class A pan evaporation data. In MLP method, four different training algorithms, gradient descent with momentum and adaptive learning rule backpropagation (GDX), Levenberg-Marquardt (LVM), scaled conjugate gradient (SCG), and resilient backpropagation (RBP), were used. Also, ?-SVR model was used as SVR model. The models were designed via 10-fold cross-validation (CV); algorithm performance was assessed via mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R 2). According to the performance criteria, the ANN algorithms and ?-SVR had similar results. The ANNs and ?-SVR methods were found to perform better than the Romanenko and Meyer methods. Consequently, the best performance using the test data was obtained using SCG(4,2,2,1) with R 2 = 0.905.

Tezel, Gulay; Buyukyildiz, Meral

2015-02-01

202

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.

Richard Hand

2006-03-01

203

Characteristic lengths for evaporation suppression from patchy porous surfaces  

NASA Astrophysics Data System (ADS)

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

Lehmann, Peter; Or, Dani

2014-05-01

204

Evaporation and transport of water isotopologues from Greenland lakes  

NASA Astrophysics Data System (ADS)

Water isotopes are a vital tracer for determining the evaporative source of precipitated water. However, estimates of the isotopic composition of evaporated moisture remain poorly constrained. Our goals were to show that isotopic profiles from a single lake source are observable, simulate these profiles with a simple mass conservation model, better constrain estimates of turbulent diffusion and evaporation using isotopes, and determine if a previously developed model can predict the observed isotopic flux of evaporated moisture accurately under our study conditions. Using an LGR water vapor isotope analyzer, we recorded vertical and horizontal vapor gradients over Greenland lakes 150 m to 5.5 km across under steady-state dominated conditions. We compared model simulations with field observations of humidity and isotopic profiles to determine the best-fit value for the model's turbulent diffusion parameter, allowing us to calculate evaporation rates. The model produced plausible profiles of vapor concentrations above 0.5 m, but overestimated humidity near the water surface. Our calculated evaporation rate decreased as fetch increased contrary to previous studies that show relatively constant evaporation with distance. Part of this discrepancy might have been caused by model simplifications such as assuming horizontally uniform wind speed. Our results also showed that, during gusts, wind speed and vapor concentrations are positively correlated indicating that concentration increase caused by greater turbulence transport outweighed the concentration decrease caused by shorter transit time of advection. Incorporating isotopic data reduced statistical error in evaporation estimates by a factor of two. Estimated evaporation rates, although lower than expected, are within error of rates estimated using an empirical model based on previous Arctic lake studies. We also showed that a model for predicting isotopic ratios of the evaporative flux over ocean produced inaccurate results when applied to lakes due to their smaller fetch. The methods used in our study present a more adequate alternative in lake studies.

Lauder, Alex

205

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

206

Evaporation Dynamics of Moss and Bare Soil in Boreal Forests  

NASA Astrophysics Data System (ADS)

Evaporation dynamics of mosses is a critical process in boreal and arctic systems and represents a key uncertainty in hydrology and climate models. At this point, moss evaporation is not well quantified at the plot or landscape scale. Relative to bare soil or litter evaporation, moss evaporation can be challenging to predict because the water flux is not isolated to the moss surface. Evaporation can originate from nearly 10 cm below the surface. Some mosses can wick moisture from even deeper than 10 cm, which subsequently evaporates. The goal of this study was to use field measurements to quantify the moss evaporation dynamics in a coniferous forest relative to bare ground or litter evaporation dynamics in a deciduous forest in Interior Alaska. Measurements were made in two ecosystem types within the boreal forest of Interior Alaska: a deciduous forest devoid of moss and a coniferous forest with a thick moss layer. A small clear chamber was attached to a LiCor 840 infrared gas analyzer in a closed loop system with a low flow rate. Water fluxes were measured for ~ 90 seconds on each plot in dry and wet soil and moss conditions. Additional measurements included: soil temperature, soil moisture, air temperature, barometric pressure, dew point, relative humidity, and wind speed. Thermal infrared images were also captured in congruence with water flux measurements to determine skin temperature. We found that the moss evaporation rate was over 100% greater than the soil evaporation rate (0.057 g/min vs. 0.024 g/min), and evaporation rates in both systems were most strongly driven by relative humidity and surface temperature. Surface temperature was lower at the birch site than the black spruce site because trees shade the surface beneath the birch. High fluxes associated with high water content were sustained for a longer period of time over the mosses compared to the bare soil. The thermal IR data showed that skin temperature lagged the evaporation flux, such that the evaporation would peak immediately following wetting of the surface but the skin temperatures responded by decreasing 20 minutes later. This study shows the evaporation dynamics of moss and bare ground, which will be incorporated into a hydrology model evaluating freshwater generation from the boreal forest.

Dempster, S.; Young, J. M.; Barron, C. G.; Bolton, W. R.

2013-12-01

207

Convective flows in evaporating sessile droplets.  

PubMed

The evaporation rate and internal convective flows of a sessile droplet with a pinned contact line were formulated and investigated numerically. We developed and analyzed a unified numerical model that includes the effects of temperature, droplet volume, and contact angle on evaporation rate and internal flows. The temperature gradient on the air/liquid interface causes an internal flow due to Marangoni stress, which provides good convective mixing within the droplet, depending upon Marangoni number. As the droplet volume decreases, the thermal gradient becomes smaller and the Marangoni flow becomes negligible. Simultaneously, as the droplet height decreases, evaporation-induced flow creates a large jet-like flow radially toward the contact line. For a droplet containing suspended particles, this jet-like convective flow carries particles toward the contact line and deposits them on the surface, forming the so-called "coffee ring stain". In addition, we reported a simple polynomial correlation for dimensionless evaporation time as a function of initial contact angle of the pinned sessile droplet which agrees well with the previous experimental and numerical results. PMID:24512008

Barmi, Meysam R; Meinhart, Carl D

2014-03-01

208

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

209

On the Effect of the Atmosphere on the Evaporation of Sessile Droplets of Water  

E-print Network

On the Effect of the Atmosphere on the Evaporation of Sessile Droplets of Water K. Sefiane1 , S. K into the effect of the atmosphere on the evaporation of pinned sessile droplets of water is described. The experimental work investigated the evaporation rates of sessile droplets in atmospheres of three different

Mottram, Nigel

210

Dynamic evaporating evolution of profiles for micro droplets on flat surfaces with hydrophilic and hydrophobic treatments  

Microsoft Academic Search

We report the experimental and analysis results of evaporation rates for micro droplets deposited onto flat surfaces that exhibit various hydrophobic and hydrophilic properties. These droplets are pure water regularly used as solvents of evaporative liquid solutions, in which different solid solutes can form versatile microstructures for patterning after dried. Evaporation tests have demonstrated that these micro droplets show significantly

Kun-Ze Tu; Chin-Tai Chen

2011-01-01

211

The effect of evaporation on the capillary pressure in heat pipes  

Microsoft Academic Search

The study deals with the dynamics of the evaporation process in the pores of heat pipe wicks. The qualitative effect of increasing evaporation rates in capillary pumped devices on the capillary pressure is measured near the contact line within the representative pores in the wick. A wedgelike approximation of an evaporating meniscus is employed in the analysis along with a

K. P. Hallinan; W. S. Chang

1991-01-01

212

A Mathematical Model of the Evaporation of a Thin Sessile Liquid Droplet: Comparison  

E-print Network

, and on the atmospheric pressure. Key words: Evaporation; Liquid Droplet; Evaporative Cooling; Atmospheric Pressure. 1 and the substrate, and the atmospheric pressure can have a sig- nificant effect on the total evaporation rate on the atmospheric pressure. For simplicity, the present initial model is, however, restricted to the special case

Mottram, Nigel

213

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

214

Method of evaporation  

NASA Technical Reports Server (NTRS)

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

Dufresne, Eugene R.

1987-01-01

215

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).

216

Pan-STARRS Moving Object Processing System  

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

217

Pattern formation in evaporating drops  

NASA Astrophysics Data System (ADS)

The redistribution of organic solutes during drop evaporation is a nanoscale self assembly process with relevance to technologies ranging from inkjet printing of organic displays to synthesis of bio-smart interfaces for sensing and screening. Atomic force microscopy studies comparing the behavior of different generation dendrimers with different surface chemistry in two solvent alcohols on mica substrates confirm that the detailed morphologies of condensed dendrimer ring structures resulting from micro-droplet evaporation sensitively depend on the surface chemistry, the solute evaporation rate and the dendrimer generation. For the dilute concentration studied here the presence of periodically 'scalloped' molecular rings is ubiquitous. The instability wavelength of the scalloped rings is found to be proportional to the width of the ring, similar to observations of the rim instability in dewetting holes. The effect of the surface chemistry of the dendrimer molecules is obvious in the detailed structure of the self assembled rings. Varying the chain length of solvent alcohol leads to modification of ring patterns. The influence of dendrimer generation on ring structure primarily reflects the increase in dendrimer density with generation number. The evolution of G2-50%C12 -pentanol rings as a function of dendrimer concentration is also described. High surface mobility and phase transformation phenomena in condensed, micro-scale dendrimer structures are documented, again using atomic force microscopy. Stratified dendrimer rings undergo dramatic temperature, time and dendrimer generation dependent morphological changes associated with large-scale molecular rearrangements and partial melting. These transformations produce ring structures consisting of a highly stable first monolayer of the scalloped structure in equilibrium with spherical cap shaped dendrimer islands that form at the center of each pre-existing scallop (creating a 'pearl necklace' structure). Analysis of the dendrimer island shapes reveals a dependence of island contact angle on contact line curvature (island size) that varies systematically with dendrimer generation. The morphological transformations in this system indicate the potential for creating complex, dendrimer-based multilevel structures and macroscopic scale arrays using, for example, droplet-on-demand or dip pen nanolithography techniques, coupled with appropriate annealing and stabilizing treatments.

Li, Fang-I.

218

Soil, Water and Atmospheric Processes 2h Tutorial Evaporation Simulation of Evaporation.  

E-print Network

form to Ohm's Law ­ for a given potential difference (voltage), current will flow at a rate determined transfer processes. You will use a simulation model of the evaporation process (essentially the PenmanKeating. Activities Log on to the university network and use the FireFox browser to navigate to one of the pages

Moncrieff, John B.

219

Representative shuttle evaporative heat sink  

NASA Technical Reports Server (NTRS)

The design, fabrication, and testing of a representative shuttle evaporative heat sink (RSEHS) system which vaporizes an expendable fluid to provide cooling for the shuttle heat transport fluid loop is reported. The optimized RSEHS minimum weight design meets or exceeds the shuttle flash evaporator system requirements. A cold trap which cryo-pumps flash evaporator exhaust water from the CSD vacuum chamber test facility to prevent water contamination of the chamber pumping equipment is also described.

Hixon, C. W.

1978-01-01

220

The Pan-STARRS1 Surveys  

NASA Astrophysics Data System (ADS)

Pan-STARRS1 is approaching the completion of the PS1 Science Mission. Operations of the PS1 System include the Observatory, Telescope, 1.4 Gigapixel Camera, Image Processing Pipeline , PSPS relational database and reduced science product software servers. The Pan-STARRS1 Surveys include: (1) A 3pi Steradian Survey, (2) A Medium Deep survey of 10 PS1 footprints spaced around the sky; (3) A solar system survey optimized for Near Earth Objects, (4) a Stellar Transit Survey; and (5) a Deep Survey of M31. The PS1 3pi Survey has now covered the sky north of dec=-30 with more than 12 visits in five bands: g,r,i,z and y or over ~60 epochs per 0.25 arcsec resolution element on the sky. The performance of the PS1 system, sky coverage, cadence, and data quality of the Pan-STARRS1 Surveys will be presented as well as progress in reprocessing of the data taken to date and the plans for the public release of all Pan-STARRS1 data products in the spring of 2015. The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation under Grant No. AST-1238877, the University of Maryland, and Eotvos Lorand University (ELTE).

Chambers, Kenneth C.

2014-01-01

221

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

222

Facile approach to synthesize g-PAN/g-C3N4 composites with enhanced photocatalytic H2 evolution activity.  

PubMed

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

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

2014-05-28

223

Ten years of pan-genome analyses.  

PubMed

Next generation sequencing technologies have engendered a genome sequence data deluge in public databases. Genome analyses have transitioned from single or few genomes to hundreds to thousands of genomes. Pan-genome analyses provide a framework for estimating the genomic diversity of the dataset at hand and predicting the number of additional whole genomes sequences that would be necessary to fully characterize that diversity. We review recent implementations of the pan-genome approach, its impact and limits, and we propose possible extensions, including analyses at the whole genome multiple sequence alignment level. PMID:25483351

Vernikos, George; Medini, Duccio; Riley, David R; Tettelin, Hervé

2015-02-01

224

Multilayer composite material and method for evaporative cooling  

NASA Technical Reports Server (NTRS)

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

Buckley, Theresa M. (Inventor)

2002-01-01

225

Capillary evaporation in pores  

NASA Astrophysics Data System (ADS)

We combine a density functional theory (DFT) treatment of capillary evaporation in a cylindrical pore with the morphometric approach in order to study the formation and breaking of bubbles in a hydrophobically lined part of a cone. The morphometric approach, in which the grand potential of a system is described in four geometrical terms with corresponding thermodynamical coefficients, allows extrapolation or scaling from macroscopic system sizes to nanoscales. Since only a small number of fluid particles are involved in bubble formation, it is a pseudo phase transition, and the system is subjected to fluctuations between states with and without a bubble. Fluctuations are not included in a DFT treatment, which makes it possible to explore both states of the system in great detail, in contrast to computer simulations, in which averages might be obscured by fluctuations.

Roth, R.; Kroll, K. M.

2006-07-01

226

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

227

Evaporation-driven instability of the precorneal tear film.  

PubMed

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

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

2014-04-01

228

Analysis of the effects of evaporative cooling on the evaporation of liquid droplets using a combined field approach  

NASA Astrophysics Data System (ADS)

During liquid evaporation, the equations for the vapor concentration in the atmosphere and for the temperature in the liquid are coupled and must be solved in an iterative manner. In the present paper, a combined field approach which unifies the coupled fields into one single hybrid field and thus makes the iteration unnecessary is proposed. By using this approach, the influences of the evaporative cooling on the evaporation of pinned sessile droplets are investigated, and its predictions are found in good agreement with the previous theoretical and experimental results. A dimensionless number Ec which can evaluate the strength of the evaporative cooling is then introduced, and the results show that both the evaporation flux along the droplet surface and the total evaporation rate of the droplet decrease as the evaporative cooling number Ec increases. For drying droplets, there exists a critical value EcCrit below which the evaporative cooling effect can be neglected and above which the significance of the effect increases dramatically. The present work may also have more general applications to coupled field problems in which all the fields have the same governing equation.

Xu, Xuefeng; Ma, Liran

2015-02-01

229

The Pan-STARRS search for Near Earth Objects  

NASA Astrophysics Data System (ADS)

The two Pan-STARRS telescopes, located on Haleakala, Maui, Hawaii, are 1.8-meter diameter telescopes equipped with 1.4 Gigapixel cameras that deliver 7 square degree fields of view. The first of these telescopes, Pan-STARRS1 (PS1), is now conducting a dedicated survey for Near-Earth Objects. The second telescope, Pan-STARRS2 (PS2) is being commissioned. It will initially supplement the PS1 search by targeting Near Earth Objects (NEO) candidates from PS1. As its efficiency grows, PS2 also will search for NEOs, and will increase the sky coverage and cadence.PS1 is cooperating with the G96 telescope of the Catalina Sky Survey in terms of field selection. Between declinations of -30 and +40 degrees, the telescopes alternate 1 hour-wide RA stripes each night. This strategy has led to increased productivity, and eliminated accidental repeats of fields. The PS1 survey area has been extended south to -47.5 degrees declination. The image quality in the deep south sky from Haleakala is good, and the new southern extension to the survey area has been very productive.PS1 has discovered more than half of the larger NEOs and PHAs in 2014 to date, and has become the leading NEO discovery telescope. PS1 delivers excellent astrometry and photometry. PS1 continues to discover a significant number of large (> 1km) NEOs.The present discovery rate of NEO candidates by PS1 is now overwhelming the external NEO followup resources. particularly for fainter NEOs. It has required that PS1 repeat fields to recover NEO candidates. As PS2 matures, and when G96 has its new camera, the combination of these three telescopes will facilitate a higher NEO discovery rate, and a better census of the NEOs in the sky. This will in turn lead to a better understanding of the size and orbit distribution of NEOs. The Pan-STARRS NEO survey is also likely to discover asteroids suitable for the NASA asteroid retrieval mission.

Wainscoat, Richard J.; Bolin, Bryce; Chambers, Kenneth; Chastel, Serge; Denneau, Larry; Micheli, Marco; Schunova, Eva; Veres, Peter

2014-11-01

230

The desorptivity model of bulk soil-water evaporation  

NASA Technical Reports Server (NTRS)

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

Clapp, R. B.

1983-01-01

231

Characterization and sequence of the Escherichia coli panBCD gene cluster  

Microsoft Academic Search

A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of aspartate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by

William K. Merkel; Brian P. Nichols

1996-01-01

232

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

USGS Publications Warehouse

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

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

2000-01-01

233

Modeling of the Cryogenic Liquid Pool Evaporation and the Effect of the Convective Heat Transfer from Atmosphere  

E-print Network

on the role of evaporation and convection phenomena on the cryogenic pool temperature and its vaporization rate. Various models describing heat transfer by evaporation were compared. The models differ from each other in terms of mass transfer coefficient...

Nawaz, Waqas

2014-04-25

234

Externally Induced Evaporation of Young Stellar Disks in Orion  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

235

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

236

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, John D. (Kennewick, WA); Gross, Mark E. (Pasco, WA)

1997-01-01

237

Metastatic Insulinoma: Current Molecular and Cytotoxic Therapeutic Approaches for Metastatic Well-Differentiated panNETs.  

PubMed

Pancreatic neuroendocrine tumors (panNETs) are a type of neuroendocrine tumor with 5-year overall survival rates of approximately 50% when metastasis is present at diagnosis. Tumor grade, as defined by Ki-67 proliferation index, influences overall survival, with low-grade tumors portending a better outcome than intermediate- and high-grade tumors. This case report follows the clinical course and management of a patient with an insulin-secreting metastatic panNET who died 10 years after diagnosis after a treatment course with regional therapy and multiple forms of cytotoxic and molecularly targeted agents. This report presents the various treatment options available for patients with insulin-secreting metastatic panNETs. PMID:25691605

Giuroiu, Iulia; Reidy-Lagunes, Diane

2015-02-01

238

Pan-STARRS Document Control PSDC-002-011-xx  

E-print Network

Pan-STARRS Document Control PSDC-002-011-xx UNIVERSITY OF HAWAII AT MANOA Institute for Astrononmy, Hawaii 96822 An Equal Opportunity/Affirmative Action Institution #12;Pan-STARRS PSDC-002-011-xx Revision, 2004 #12;Pan-STARRS PSDC-002-011-xx Abstract We consider the problem of combining astronomical images

Masci, Frank

239

Diophantine Analysis and Brownie Pan Optimization Michael Wilson  

E-print Network

Diophantine Analysis and Brownie Pan Optimization Michael Wilson Department of Mathematics, fold up the resulting flaps, and (after some welding, one presumes) make a brownie pan. The question is to be a square, measuring L Ã? L. If we cut out corner squares measuring t Ã? t, where 0 t L/2, the brownie pan

Wilson, J. Michael

240

Pan-STARRS1, Pan-STARRS2, ATLAS and the future of optical transient searches  

E-print Network

QE ­ Construction funded by AFRL ­ First light Aug 07, science ops ~Jun 09 ­ Current operations% of time) ­ Nightly observations of North Celestial Pole ­ Pandromeda ­ PanPlanets ­ AFRL GEO observations

Hinton, Jim

241

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

Federal Register 2010, 2011, 2012, 2013, 2014

...we partner with friends and neighbors across the Americas. Our combined response to this year's devastating earthquakes in Haiti and Chile demonstrates the enduring strength of Pan American solidarity. As we mourn these tragic losses of...

2010-04-14

242

*** How PAN based Carbon Fibers are  

E-print Network

*** How PAN based Carbon Fibers are Manufactured *** How Carbon Fiber Material Properties was the lead engineer in manufacturing of numerous advanced composite structures for the AV8B Jump Jet, F16, F as a Business Development Manager for Amoco's carbon fiber business unit (manufacturers of T-300 carbon fiber

Hu, Hui

243

Polyacrylonitrile (PAN) membranes for ultra- and microfiltration  

Microsoft Academic Search

Polyacrylonitrile (PAN) membranes for ultra- and microfiltration were developed by GKSS. They are fabricated on a non-woven by a phase inversion process. It is shown that the formation process mainly depends on the polymer concentration of the casting solution as well as on the temperature of the precipitation bath. Therefore, different membrane morphologies can be obtained. They vary from large

Nico Scharnagl; Heinz Buschatz

2001-01-01

244

Pan-STARRS1 3Pi transients  

NASA Astrophysics Data System (ADS)

The Pan-STARRS1 telescope has been carrying out the "3Pi" survey of the whole sky north of -30 degrees since 2010 in grizy (PS1 specific filters). Each region on the sky is typically visited four times a year in each filter.

Smartt, S. J.; Smith, K. W.; Wright, D.; Young, D. R.; Kotak, R.; Nicholl, M.; Polshaw, J.; Inserra, C.; Chen, T.-W.; Terreran, G.; Gall, E.; Fraser, M.; McCrum, M.; Valenti, S.; Foley, R.; Lawrence, A.; Gezari, S.; Burgett, W.; Chambers, K.; Huber, M.; Kudritzki, R. P.; Magnier, E.; Morgan, J.; Tonry, J.; Sweeney, W.; Stubbs, C. Waters C.; Kirshner, R.; Metcalfe, N.; Rest, P. Draper A.

2014-02-01

245

The Pan-STARRS Survey Telescope Project  

NASA Astrophysics Data System (ADS)

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 consist of an array of four 1.8m telescopes with very large (7 square degree) field of view, giving it an etendue larger than all existing survey instruments combined. Each telescope will be equipped with a 1.4 billion pixel CCD camera with low noise and rapid read-out, and the data will be reduced in near real time to produce both cumulative static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to scan the entire visible sky to approximately 24th magnitude in less than a week, and this unique combination of sensitivity and cadence will open up many new possibilities in time domain astronomy. A major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. In addition, the Pan-STARRS data will used to address a wide range of astronomical problems in the Solar System, the Galaxy, and the Cosmos at large.

Kaiser, N.; Pan-STARRS Team

2005-12-01

246

Placental retention in a bonobo ( Pan paniscus )  

Microsoft Academic Search

Background This case report describes the first placental retention in an 11- year-old female bonobo (Pan paniscus) following the delivery of a healthy infant. Methods After unsuccessful medical treatment with oxytocin, the placenta was manually extracted. Results and conclusions Both the dam and infant survived.

Michel Halbwax; Crispin Kamate Mahamba; Anne-Marie Ngalula; Claudine André

2009-01-01

247

Charge consequences in electrospun polyacrylonitrile (PAN) nanofibers  

Microsoft Academic Search

During the last 10 years extensive research has been conducted on various aspects of electrospinning. These efforts include spinning many different polymer and solvent pairs, varying fiber forming conditions, fiber characterization and process modeling. In this work we explore some issues related to charging of the polymer solution, namely charge quantification of electrospun fibers and different charge delivery designs. PAN

Veli E. Kalayci; Prabir K. Patra; Yong K. Kim; Samuel C. Ugbolue; Steven B. Warner

2005-01-01

248

Optimization of the Brownie Pan Briana Oshiro  

E-print Network

Optimization of the Brownie Pan Briana Oshiro bsoshiro@uw.edu Patrick Larson palarson@uw.edu Sunjay that Lam´e Curves approach a square 7 1 Introduction A brownie is a terrible thing to waste. It is a shame is no longer used efficiently, and again, a brownie is a terrible thing to waste. It is with these issues

Morrow, James A.

249

Rotatable prism for pan and tilt  

NASA Technical Reports Server (NTRS)

Compact, inexpensive, motor-driven prisms change field of view of TV camera. Camera and prism rotate about lens axis to produce pan effect. Rotating prism around axis parallel to lens produces tilt. Size of drive unit and required clearance are little more than size of camera.

Ball, W. B.

1980-01-01

250

The evaporative function of cockroach hygroreceptors.  

PubMed

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

Tichy, Harald; Kallina, Wolfgang

2013-01-01

251

ENSO and multi-decadal 'trends' in continental evaporation  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

252

Influence of surface wettability on transport mechanisms governing water droplet evaporation.  

PubMed

Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ? 60°), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ? CA ? 90°), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ? 90°), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ? 90°) when evaporative cooling is strong and the temperature gradient along the interface determines the peak local evaporation flux. PMID:25105726

Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

2014-08-19

253

The Pan-STARRS Survey Telescope Project  

NASA Astrophysics Data System (ADS)

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. The project is proceeding in two phases: PS1 is a single aperture system that has been deployed on Haleakala on Maui and the full 4-aperture system PS4 will be sited on Mauna Kea and is scheduled to become operational in late 2010. The data from Pan-STARRS will be reduced in near real time to produce both a cumulative image of the static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to scan the entire visible sky to approximately 24th magnitude in less than a week, and this unique combination of sensitivity and cadence will open up many new possibilities in time domain astronomy. A major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. In addition, the Pan-STARRS data will provide a dramatic leap in data quality and extent over existing wide-field image durvey data that will be used to advance our understanding of the formation of the Solar System, the Galaxy, and the Cosmos at large. In this talk I will describe the science drivers for the project; review the technical design and performance metrics for various scientific gols; and give an update on the current status and future time-line of the project.

Kaiser, N.

254

Impact of ambient conditions on evaporation from porous media  

NASA Astrophysics Data System (ADS)

The complexity of soil evaporation, depending on the atmospheric conditions, emphasizes the importance of its quantification under potential changes in ambient air temperature, Ta, and relative humidity, RH. Mass loss, soil matric tension, and meteorological measurements, carried out in a climate-controlled laboratory, were used to study the effect of ambient conditions on the drying rates of a porous medium. A set of evaporation experiments from initially saturated sand columns were carried out under constant Ta of 6, 15, 25, and 35°C and related RH (0.66, 0.83, 1.08, and 1.41 kPa, respectively). The results show that the expected increase of the stage 1 (S1) evaporation rate with Ta but also revealed an exponential-like reduction in the duration of S1, which decreased from 29 to 2.3 days (at Ta of 6 and 35°C, respectively). The evaporation rate, e(t), was equal to the potential evaporation, ep(t), under Ta = 6°C, while it was always smaller than ep(t) under higher Ta. The cumulative evaporation during S1 was higher under Ta = 6°C than under the higher temperatures. Evaporation rates during S2 were practically unaffected by ambient conditions. The results were analyzed using a mass transfer formulation linking e(t) with the vapor pressure deficit through a resistance coefficient r. It was shown that rS1 (the resistance during S1) is constant, indicating that the application of such an approach is straightforward during S1. However, for evaporation from a free water surface and S2, the resistances, rBL and rS2, were temperature-dependent, introducing some complexity for these cases.

Ben Neriah, Asaf; Assouline, Shmuel; Shavit, Uri; Weisbrod, Noam

2014-08-01

255

A spatially explicit model of runoff, evaporation, and lake extent: Application to modern and late Pleistocene lakes in the Great Basin region, western United States  

Microsoft Academic Search

A spatially explicit hydrological model was applied to the Great Basin in the western United States to predict runoff magnitude and lake distributions under modern and late Pleistocene conditions. The model iteratively routes runoff through depression to find a steady state solution and was calibrated with mean annual precipitation, pan evaporation, temperature, and stream runoff data. The predicted lake distribution

Yo Matsubara; Alan D. Howard

2009-01-01

256

Trends in evaporation and surface cooling in the Mississippi River basin  

USGS Publications Warehouse

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

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

2001-01-01

257

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

258

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

259

Thermoelectric integrated membrane evaporation water recovery technology  

NASA Technical Reports Server (NTRS)

The recently developed Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) offers a highly competitive approach to water recovery from waste fluids for future on-orbit stations such as the Space Operations Center. Low power, compactness and gravity insensitive operation are featured in this vacuum distillation subsystem that combines a hollow fiber membrane evaporator with a thermoelectric heat pump. The hollow fiber elements provide positive liquid/gas phase control with no moving parts other than pumps and an accumulator, thus solving problems inherent in other reclamation subsystem designs. In an extensive test program, over 850 hours of operation were accumulated during which time high quality product water was recovered from both urine and wash water at an average steady state production rate of 2.2 pounds per hour.

Roebelen, G. J., Jr.; Winkler, H. E.; Dehner, G. F.

1982-01-01

260

Personality assessment in the Great Apes: Comparing ecologically valid behavior measures, behavior ratings, and adjective ratings  

Microsoft Academic Search

Three methods of personality assessment (behavior measures, behavior ratings, adjective ratings) were compared in 20 zoo-housed Great Apes: bonobos (Pan paniscus), chimpanzees (Pan troglodytes verus), gorillas (Gorilla gorilla gorilla), and orangutans (Pongo pygmaeus abelii). To test a new bottom-up approach, the studied trait constructs were systematically generated from the species’ behavioral repertoires. The assessments were reliable, temporally stable, and showed

Jana Uher; Jens B. Asendorpf

2008-01-01

261

PAN/PS elctrospun fibers for oil spill cleanup  

NASA Astrophysics Data System (ADS)

A high-capacity oil sorbent was fabricated by electrospinning using PS/PAN blend. Morphology, contact angle and oil adsorption of PAN/PS fiber and PP nonwoven fabric were studied. It was found that the PAN/PS fiber had a smaller diameter than PP, and the maximum sorption capacities of the PAN/PS sorbent for pump oil, peanut oil, diesel, and gasoline were 194.85, 131.7, 66.75, and 43.38 g/g, which were far higher than those of PP. The sorbent PS/PAN fiber showed a contact angle of water144.32° and diesel oil 0°. The sorption kinetics of PAN/PS and PP sorbent were also investigated. Compared with the commercial PP fabric, the PAN/PS fiber seems to have the ability to be used in oil-spill cleanup application.

Ying, Qiao; Lili, Zhao; Haixiang, Sun; Peng, Li

2014-08-01

262

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

263

Evaporative cooling of flare plasma  

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

264

IMPROVEMENTS TO NVIZ Haiping Pan  

E-print Network

3.3.3 Pick Button and Reset Button 3.3.4 Time Slider 3.3.5 Control Button Group 3.3.6 Message Box 3 for Statistics Menu 3.7.1 Plot Interval Histogram 3.7.2 Plot Cell Firings 3.7.3 Rate Meter Plot 3.7.4 Cell Correlation 3.7.5 From (soma)-Time Plot to PotCnod(Dendr)-Time Plot Chapter 4 - New Features in NVIZ 4.1 Ruler

Subramanian, Kalpathi R.

265

Pan-STARRS: a wide-field optical survey telescope array  

NASA Astrophysics Data System (ADS)

The Institute for Astronomy at the University of Hawaii is developing a large optical synoptic survey telescope system; the Panoramic Survey Telescope and Rapid Response System. Pan-STARRS will consist of an array of four 1.8m telescopes with very large (7 square degree) field of view, giving it an etendue larger than all existing survey instruments combined. Each telescope will be equipped with a 1 billion pixel CCD camera with low noise and rapid read-out, and the data will be reduced in near real time to produce both cumulative static sky and difference images, from which transient, moving and variable objects can be detected. Pan-STARRS will be able to survey up to ?6,000 square degrees per night to a detection limit of approximately 24th magnitude. This unique combination of sensitivity and rate of area coverage will open up many new possibilities in time domain astronomy. A major goal for the project is to survey potentially dangerous asteroids, where Pan-STARRS will be able to detect most objects down to 300m size, much smaller than the km size objects accessible to existing search programs. In addition, the Pan-STARRS data products will used to address a wide range of astronomical problems in the Solar System, the Galaxy, and the Cosmos at large. Here, we first outline the Pan-STARRS science goals and describe the survey modes needed to support these. We then describe the design and performance goals, the data processing pipeline, and we review the basic data products. Finally, we present results from simulations that demonstrate Pan-STARRS' capability for detecting potentially hazardous asteroids.

Kaiser, Nicholas

2004-10-01

266

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

2013-03-15

267

Evaporation Tower With Prill Nozzles  

NASA Technical Reports Server (NTRS)

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

Du Fresne, E. R.

1984-01-01

268

BRDF of Salt Pan Regolith Samples  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

269

Microdroplet evaporation with a forced pinned contact line.  

PubMed

Experimental and numerical investigations of water microdroplet evaporation on heated, laser patterned polymer substrates are reported. The study is focused on both (i) controlling a droplet's contact line dynamics during evaporation to identifying how the contact line influences evaporative heat transfer and (ii) validating numerical simulations with experimental data. Droplets are formed on the polymer surface using a bottom-up methodology, where a computer-controlled syringe pump feeds water through a 200 ?m diameter fluid channel within the heated polymer substrate. This methodology facilitates precise control of the droplet's growth rate, size, and inlet temperature. In addition to this microchannel supply line, the substrate surfaces are laser patterned with a moatlike trench around the fluid-channel outlet, adding additional control of the droplet's contact line motion, area, and contact angle. In comparison to evaporation on a nonpatterned polymer surface, the laser patterned trench increases contact line pinning time by ?60% of the droplet's lifetime. Numerical simulations of diffusion controlled evaporation are compared the experimental data with a pinned contact line. These diffusion based simulations consistently over predict the droplet's evaporation rate. In efforts to improve this model, a temperature distribution along the droplet's liquid-vapor interface is imposed to account for the concentration distribution of saturated vapor along the interface, which yields improved predictions within 2-4% of the experimental data throughout the droplet's lifetime on heated substrates. PMID:25102248

Gleason, Kevin; Putnam, Shawn A

2014-09-01

270

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

Microsoft Academic Search

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

D. Wallace; C. Sagan

1979-01-01

271

Pan abode naturally passive solar homes  

SciTech Connect

Currently Pan Abode markets 30 stock models of solid timber homes. In these homes the interior and exterior walls are of solid timber construction. Wall timbers, made from Western Red Cedar, are precut at the factory in Renton, Washington and then shipped to the site for assembly. Once at the site, the wall timbers are stacked according to the approved plans with timbers laid up throughout the house one course at a time. Ceilings in the Pan Abode homes are exposed beam with 2'' x 6'' sheathing. The large amount of exposed wood in the Pan Abode homes naturally provides the thermal mass necessary for a high performance passive solar home. The best selling stock model for Pan Abode is the Standard Cavalier. Because this home is the best selling model, it is selected as the base case for the development of a passive solar product line. The design objective is to modify the Standard Cavalier making use of its natural thermal mass to provide significantly improved thermal performance while minimizing any increases in the first costs attributed to passive solar design. Two generic passive solar systems are considered in the design process. The first system is ''direct gain.'' In this system the south windows are used to collect winter sun and the natural thermal mass inside the home is used to moderate the interior temperatures, storing and releasing solar heat, as necessary. The second system provides for a room addition to the basic house of an Energy Wing Solarium. The Energy Wing provides improved thermal performance to the Cavalier and provides a sun room, as well. In this system south facing windows on the Energy Wing collect sunlight in the winter. The design options, thermal performance, market and cost are discussed.

Steel, G.B.

1981-03-01

272

EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS  

SciTech Connect

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

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

2013-02-20

273

Desiccant Enhanced Evaporative Air Conditioning: Parametric Analysis and Design; Preprint  

SciTech Connect

This paper presents a parametric analysis using a numerical model of a new concept in desiccant and evaporative air conditioning. The concept consists of two stages: a liquid desiccant dehumidifier and a dew-point evaporative cooler. Each stage consists of stacked air channel pairs separated by a plastic sheet. In the first stage, a liquid desiccant film removes moisture from the process (supply-side) air through a membrane. An evaporatively-cooled exhaust airstream on the other side of the plastic sheet cools the desiccant. The second-stage indirect evaporative cooler sensibly cools the dried process air. We analyze the tradeoff between device size and energy efficiency. This tradeoff depends strongly on process air channel thicknesses, the ratio of first-stage to second-stage area, and the second-stage exhaust air flow rate. A sensitivity analysis reiterates the importance of the process air boundary layers and suggests a need for increasing airside heat and mass transfer enhancements.

Woods, J.; Kozubal, E.

2012-10-01

274

Silicon anode prepared by rotary evaporation for lithium ion batteries  

NASA Astrophysics Data System (ADS)

A rotary evaporation process was applied to improve electrical contact between acetylene black (AB) and Si electrode. Morphologies and electrochemical properties of the Si electrode were compared with those of conventionally prepared Si electrode. In the evaporated Si electrode, AB particles consisted of network-like structure surrounding the surface of Si particle, while in the conventional one, AB particles partially stuck on the Si surface. Increasing the current density from 0.1 to 0.5 C, stable cycle behavior with a slight decrease in discharge capacity was found in the evaporated electrode, while unstable cycle behavior with a significantly decreased capacity was observed in the conventional electrode. At high-current density (0.5 C rate), the discharge capacity of the evaporated Si electrode was maintained over 480 mAh g-1 after 100 cycles. The good cycle performance was attributed to the low resistance induced by the improved interfacial contact between AB and Si particles.

Shin, D. H.; Cho, G. B.; Song, M. G.; Choi, Y. J.; Gu, H. B.; Kim, K. W.

2007-12-01

275

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

SciTech Connect

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

Not Available

1993-02-01

276

The Pan-STARRS solar system survey  

NASA Astrophysics Data System (ADS)

The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) at the University of Hawaii's Institute for Astronomy is a funded project to repeatedly survey the entire visible sky to faint limiting magnitudes (m_R ˜ 24). It will be composed of four 1.8m diameter telescopes each outfitted with fast readout orthogonal transfer Giga-pixel CCD cameras. One of the four telescopes is scheduled for first-light within two years with the other telescopes becoming available a couple years later. Roughly 30% of the surveying will be devoted to a solar system mode in a wide-open filter emphasizing the ecliptic, opposition and low solar-elongation regions. In a single lunation Pan-STARRS will detect about five times more solar system objects than the entire currently known sample. Within the first year it will have detected ˜20,000 Kuiper Belt Objects, by the end of its anticipated ten year operational lifetime we expect to find 10^7 Main Belt objects, and we expect that it will eventually achieve ˜90% observational completeness for all NEOs larger than ˜300m diameter. With these data in hand Pan-STARRS will revolutionize our knowledge of the contents and dynamical structure of the solar sytem.

Jedicke, R.; Pan-Starrs Collaboration

277

Weak Lensing Cosmology with Pan-STARRS  

NASA Astrophysics Data System (ADS)

The Pan-STARRS wide-field imaging system will provide a dramatic leap in performance for cosmological studies using weak lensing of faint background galaxies. Pan-STARRS will use 1.8m diameter optical systems with revolutionary 1.4 giga-pixel CCD cameras, and has been designed from the outset with high precision photometry, astrometry and shape measurements as drivers. The project is proceeding in two phases: PS1 is a single aperture system that has been deployed on Haleakala on Maui and which will become fully operational this year. PS1 will operate for 3.5 years to perform a number of surveys, with the majority of the time assigned to a "3-pi" survey that will give powerful constraints on the large-scale matter power spectrum and its evolution. The full-scale four aperture system PS4 is planned to be deployed on Mauna Kea ca. 2010 with a nominal 10 year survey mission. In this talk I will describe the features of the hardware and survey design that support the challenge of high-precision cosmology from weak lensing and provide forecasts for the constraints that the Pan-STARRS surveys will provide on cosmology.

Kaiser, Nick

2007-05-01

278

Removal of aluminium from aqueous solutions using PAN-based adsorbents: characterisation, kinetics, equilibrium and thermodynamic studies.  

PubMed

Economic adsorbents in bead form were fabricated and utilised for the adsorption of Al(3+) from aqueous solutions. Polyacrylonitrile (PAN) beads, PAN powder and the thermally treated PAN beads (250 °C/48 h/Ar and 600 °C/48 h/Ar-H2) were characterised using different techniques including Fourier transform infrared spectroscopy, X-ray diffraction, specific surface analysis (Brunauer-Emmett-Teller), thermogravimetric analysis as well as scanning electron microscopy. Effects of pH, contact time, kinetics and adsorption isotherms at different temperatures were investigated in batch mode experiments. Aluminium kinetic data best fit the Lagergren pseudo-second-order adsorption model indicating a one-step, surface-only, adsorption process with chemisorption being the rate limiting step. Equilibrium adsorption data followed a Langmuir adsorption model with fairly low monolayer adsorption capacities suitable for freshwater clean-up only. Various constants including thermodynamic constants were evaluated from the experimental results obtained at 20, 40 and 60 °C. Positive values of ?H° indicated that the adsorption of Al(3+) onto all three adsorbents was endothermic with less energy input required for PAN powder compared to PAN beads and low-temperature thermally treated PAN. Negative ?G° values indicated that the aluminium adsorption process was spontaneous for all adsorbents examined. PMID:24297464

Aly, Zaynab; Graulet, Adrien; Scales, Nicholas; Hanley, Tracey

2014-03-01

279

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

280

Evaporation of pure liquid sessile and spherical suspended drops: a review.  

PubMed

A sessile drop is an isolated drop which has been deposited on a solid substrate where the wetted area is limited by a contact line and characterized by contact angle, contact radius and drop height. Diffusion-controlled evaporation of a sessile drop in an ambient gas is an important topic of interest because it plays a crucial role in many scientific applications such as controlling the deposition of particles on solid surfaces, in ink-jet printing, spraying of pesticides, micro/nano material fabrication, thin film coatings, biochemical assays, drop wise cooling, deposition of DNA/RNA micro-arrays, and manufacture of novel optical and electronic materials in the last decades. This paper presents a review of the published articles for a period of approximately 120 years related to the evaporation of both sessile drops and nearly spherical droplets suspended from thin fibers. After presenting a brief history of the subject, we discuss the basic theory comprising evaporation of micrometer and millimeter sized spherical drops, self cooling on the drop surface and evaporation rate of sessile drops on solids. The effects of drop cooling, resultant lateral evaporative flux and Marangoni flows on evaporation rate are also discussed. This review also has some special topics such as drop evaporation on superhydrophobic surfaces, determination of the receding contact angle from drop evaporation, substrate thermal conductivity effect on drop evaporation and the rate evaporation of water in liquid marbles. PMID:22277832

Erbil, H Yildirim

2012-01-15

281

The impact of humidity on evaporative cooling in small desert birds exposed to high air temperatures.  

PubMed

Environmental temperatures that exceed body temperature (Tb) force endothermic animals to rely solely on evaporative cooling to dissipate heat. However, evaporative heat dissipation can be drastically reduced by environmental humidity, imposing a thermoregulatory challenge. The goal of this study was to investigate the effects of humidity on the thermoregulation of desert birds and to compare the sensitivity of cutaneous and respiratory evaporation to reduced vapor density gradients. Rates of evaporative water loss, metabolic rate, and Tb were measured in birds exposed to humidities ranging from ?2 to 30 g H2O m(-3) (0%-100% relative humidity at 30°C) at air temperatures between 44° and 56°C. In sociable weavers, a species that dissipates heat primarily through panting, rates of evaporative water loss were inhibited by as much as 36% by high humidity at 48°C, and these birds showed a high degree of hyperthermia. At lower temperatures (40°-44°C), evaporative water loss was largely unaffected by humidity in this species. In Namaqua doves, which primarily use cutaneous evaporation, increasing humidity reduced rates of evaporative water loss, but overall rates of water loss were lower than those observed in sociable weavers. Our data suggest that cutaneous evaporation is more efficient than panting, requiring less water to maintain Tb at a given temperature, but panting appears less sensitive to humidity over the air temperature range investigated here. PMID:25461643

Gerson, Alexander R; Smith, Eric Krabbe; Smit, Ben; McKechnie, Andrew E; Wolf, Blair O

2014-01-01

282

Transient Marangoni convection in hanging evaporating drops  

NASA Astrophysics Data System (ADS)

A combined experimental and numerical analysis has been carried out to study Marangoni effects during the evaporation of droplets. The experiments are performed with pendant drops of silicone oils (with different viscosities) and hydrocarbons. The temperature of the disk sustaining the drop is rapidly increased or decreased in order to study transient heating or cooling processes. The velocity field in the droplet is evaluated monitoring the motion of tracers in the meridian plane, using a laser sheet illumination system and a video camera. Surface temperature distributions of the drops are detected by infrared thermocamera. The numerical model is based on axisymmetric Navier-Stokes equations, taking into account the presence of Marangoni shear stresses and evaporative cooling at the liquid-air interface. Marangoni flows cause a larger, more uniform surface temperature, increasing heat transfer from disk to droplet, as well as evaporation rate. When Marangoni effects are negligible, larger surface temperature differences occur along the drop surface and heat transfer is relatively small. The role of Marangoni and buoyancy flows in silicone oils with different viscosities and hydrocarbons is discussed and correlations are presented between experimental and numerical results.

Savino, R.; Fico, S.

2004-10-01

283

Evaporated Lithium Surface Coatings in NSTX  

SciTech Connect

Two lithium evaporators were used to evaporate more than 100 g of lithium on to the NSTX lower divertor region. Prior to each discharge, the evaporators were withdrawn behind shutters, where they also remained during the subsequent HeGDC applied for periods up to 9.5 min. After the HeGDC, the shutters were opened and the LITERs were reinserted to deposit lithium on the lower divertor target for 10 min, at rates of 10-70 mg/min, prior to the next discharge. The major improvements in plasma performance from these lithium depositions include: 1) plasma density reduction as a result of lithium deposition; 2) suppression of ELMs; 3) improvement of energy confinement in a low-triangularity shape; 4) improvement in plasma performance for standard, high-triangularity discharges; 5) reduction of the required HeGDC time between discharges; 6) increased pedestal electron and ion temperature; 7) reduced SOL plasma density; and 8) reduced edge neutral density.

Kugel, H. W.; Mansfield, D.; Maingi, R.; Bel, M. G.; Bell, R. E.; Allain, J. P.; Gates, D.; Gerhardt, S.; Kaita, R.; Kallman, J.; Kaye, S.; LeBlanc, B.; Majeski, R.; Menard, J.; Mueller, D.; Ono, M.

2009-04-09

284

The Performance of Refrigeration Cycle with Vapor Re-circulation Evaporator Using an Ejector  

NASA Astrophysics Data System (ADS)

We have proposed new method that re-circulates vapor refrigerant into the evaporator using an ejector to enhance the evaporating heat transfer in the refrigeration cycle. It makes the evaporating heat transfer coefficient higher by increase of the dryness-quality at the inlet of evaporator. We investigated experimentally the coefficient of performance (COP) of the refrigeration cycle and the evaporating heat transfer coefficient with a proposal means, under various evaporating and condensing temperatures and heat loads. As a result, the COP of proposed cycle is 5-13% higher than the conventional cycle with a D.C. inverter compressor by re-circulation of refrigerant. Furthermore, we investigated the dry-out length in the evaporator by authorized empirical equation and evaluated the optimum flow rate of re-circulation.

Man'o, Tatsunori; Tanino, Masayuki; Okazaki, Takashi; Koyama, Shigeru

285

Evaporation kinetics of acetic acid-water solutions  

NASA Astrophysics Data System (ADS)

The transport of water molecules across vapor-liquid interfaces in the atmosphere is a crucial step in the formation and evolution of cloud droplets. Despite decades of study, the effects of solutes on the mechanism and rate of evaporation and condensation remain poorly characterized. The present work aims to determine the effect of atmospherically-relevant solutes on the evaporation rate of water. In our experiments, we create a train of micron-sized droplets and measure their temperature via Raman thermometry as they undergo evaporation without condensation. Analysis of the cooling rate yields the evaporation coefficient (?). Previous work has shown that inorganic salts have little effect on ?, with surface-adsorbing anions causing a slight reduction in the coefficient from that measured for pure water. Organic acids are ubiquitous in aqueous aerosol and have been shown to disrupt the surface structure of water. Here we describe measurements of the evaporation rate of acetic acid solutions, showing that acetic acid reduces ? to a larger extent than inorganic ions, and that ? decreases with increasing acetic acid concentration.

Duffey, K.; Wong, N.; Saykally, R.; Cohen, R. C.

2012-12-01

286

DWPF Recycle Evaporator Simulant Tests  

SciTech Connect

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

Stone, M

2005-04-05

287

Heat Transfer Performance for Evaporator of Absorption Refrigerating Machine  

NASA Astrophysics Data System (ADS)

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

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

288

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

289

Pore scale model for evaporation dynamics from soil surfaces with patchy wetness  

NASA Astrophysics Data System (ADS)

The gradual reduction in drying rates from soil surfaces under high atmospheric demand is often attributed to constraints imposed by internal transport mechanisms limiting capillary flows from soil interior towards vaporization plane at the surface. Experimental evidence for high evaporation rates under non-limiting capillary flow conditions suggests that interactions between pore-scale diffusive fluxes from gradually drying porous surfaces and diffusive resistance across air boundary layer thickness, play a crucial role in shaping evaporation dynamics. Results from evaporation experiments using sand columns subjected to potential drying rates ranging from 2 to 30 mm/day (defined by prescribed air velocities) show that for high evaporative demands (>5 mm/day), evaporation rates decreased gradually until a transition to diffusion-controlled stage-II evaporation. In contrast, under low air velocities, a constant drying rate was established and maintained irrespective of drying of the surface or receding drying front. A pore scale model for surface coupling shows evolution of vapor density field from 1-D stratified pattern for the uniformly wet surface to 3-D vapor shells forming over active pores as the surface dries. Calculations show that per-pore vapor diffusion flux increases with increased pore spacing, reduced pore size, and boundary layer thickness. Consequently, for low evaporative demand and thick boundary layer, the resulting flux from isolated pores may fully compensate for reduced surface water content (evaporating area) resulting in constant evaporation rates. These results also suggest that flux compensation for patchy wetness is likely to be less efficient than for spatially (uniformly) distributed pores and thus results in reduced evaporation rates even for low atmospheric demand. The study will address the additional key parameter of wetness patch size and the patchiness spatial structure in relation to boundary layer thickness and impact on evaporation dynamics from heterogeneous surfaces.

Shahraeeni, E.; Lehmann, P.; Or, D.

2012-04-01

290

Sensitivity of potential evaporation estimates to 100 years of climate variability  

NASA Astrophysics Data System (ADS)

Hydrological modeling frameworks require an accurate representation of evaporation fluxes for appropriate quantification of, e.g., the water balance, soil moisture budget, recharge and groundwater processes. Many frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ("reference evaporation") by crop-specific scaling factors ("crop factors"). Though this two-step potential evaporation approach undoubtedly has practical advantages, the empirical nature of both reference evaporation methods and crop factors limits its usability in extrapolations under non-stationary climatic conditions. In this paper, rather than simply warning about the dangers of extrapolation, we quantify the sensitivity of potential evaporation estimates for different vegetation classes using the two-step approach when calibrated using a non-stationary climate. We used the past century's time series of observed climate, containing non-stationary signals of multi-decadal atmospheric oscillations, global warming, and global dimming/brightening, to evaluate the sensitivity of potential evaporation estimates to the choice and length of the calibration period. We show that using empirical coefficients outside their calibration range may lead to systematic differences between process-based and empirical reference evaporation methods, and systematic errors in estimated potential evaporation components. Quantification of errors provides a possibility to correct potential evaporation calculations and to rate them for their suitability to model climate conditions that differ significantly from the historical record, so-called no-analog climate conditions.

Bartholomeus, R. P.; Stagge, J. H.; Tallaksen, L. M.; Witte, J. P. M.

2015-02-01

291

Pan-STARRS NEO surveying: The preliminary orbit problem  

NASA Astrophysics Data System (ADS)

The University of Hawaii's Pan-STARRS project will be a deep (R ˜ 24) wide field ( ˜ 7 deg2) survey, with the goal of cataloging 90% of Potentially Hazardous Objects that are larger than about 300m diameter. It will be capable of surveying 6000 deg2/night enabling discovery rates almost two orders of magnitude greater than all existing surveys combined. No existing PHO follow-up facility can match the expected depth and discovery rate. With this in mind, it is important to select an intelligent discovery and follow-up cadence, not only for easy night-to-night linking, but also for high-quality orbit determination and efficient use of telescope time. With these concerns, we simulated a typical set of Pan-STARRS NEO observations using the Bottke et al. [1] NEO model, 0".1 RMS astrometry, and standard horizon and magnitude limits for Mauna Kea. Various cadences were investigated, including 2, 3, and 4-night data sets, with each observation night separated by four days. In addition, we varied the number of observations each night between 2 and 3 visits, with visits separated by 30 minutes. The impact of these choices on preliminary orbit determination, post-fit element uncertainties, and sky-plane uncertainties was studied. These simulations indicate that 3 observations per night is largely unnecessary, and that orbit determination using only two nights of data is not acceptable for our needs. Pairs of observations spaced by 30 minutes, and 3 or 4 separate nights of data over the corresponding 8 or 12-night interval provide well-determined orbital elements and small sky-plane uncertainties. [1] W.F. Bottke, R. Jedicke, A. Morbidelli, J.-M. Petit, B. Gladman, Science, 288, 2190-2194 (2000).

Spahr, T.; Chesley, S.; Heasley, J.; Jedicke, R.

2004-11-01

292

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

NASA Astrophysics Data System (ADS)

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

Gonzalez, Mark A.

293

Characteristic behavior of peroxyacetyl nitrate (PAN) in Seoul megacity, Korea  

Microsoft Academic Search

We measured the concentrations of peroxyacetyl nitrate (PAN) and other photochemically reactive species, including O3, NO2, and non-methane hydrocarbons (NMHCs), in the Seoul Metropolitan area (SMA) during May through June in 2004 and 2005. PAN was determined using a fast chromatograph with luminol-based chemiluminescence detection. Mixing ratios of PAN ranged from below the detection limit (0.1ppbv) to 10.4ppbv with an

Gangwoong Lee; Yuwoon Jang; Heayoung Lee; Jin-Seok Han; Kyung-Ryul Kim; Meehye Lee

2008-01-01

294

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

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

22. RW Meyer Sugar Mill: 1876-1889. Sorghum Pan. Manufactured by John Nott & Co., Honolulu, Hawaii, 1878. View: Historical view, 1934, T.T. Waterman Collection, Hawaiian Sugar Planters' Association, Oahu, Hawaii. View looking toward east end of sorghum pan and interior of east end of the boiling house. Walls and final compartment of the sorghum pan are still intact. - R. W. Meyer Sugar Mill, State Route 47, Kualapuu, Maui County, HI

295

Investigating the Spinnability in the Dry-Jet Wet Spinning of PAN Precursor Fiber  

E-print Network

fiber.1 In preparing PAN solutions for manufacturing PAN precursor fibers, the first issueInvestigating the Spinnability in the Dry-Jet Wet Spinning of PAN Precursor Fiber Lianjiang Tan,1 Huifang Chen,1 Ding Pan,1 Ning Pan2 1 State Key Laboratory for Chemical Fibers Modification and Polymer

Pan, Ning

296

WEB-BASED PPS 9.3 WEB-BASED PAN  

E-print Network

WEB-BASED PPS 9.3 WEB-BASED PAN 9.3--1 Payroll/Personnel System Web-Based PAN January 2010, University of California, Santa Cruz PPS User Manual Post Authorization Notification Functions (Web PAN) Note: This section covers web PAN features, but not general background or information about PAN. For detailed

Lee, Herbie

297

Global sources and significance of peroxyacetyl nitrate (PAN)  

NASA Astrophysics Data System (ADS)

Peroxyacetyl nitrate (PAN), formed in the atmospheric oxidation of non-methane volatile organic compounds (NMVOCs) serves as a thermally unstable reservoir for nitrogen oxide radicals (NO and NO2, collectively termed NOx). PAN permits NOx to impact the global distribution of the two most important atmospheric oxidants, ozone (O3) and the OH radical. PAN is also a critical channel through which climate-driven changes to the biosphere will affect atmospheric composition, notably through biogenic NMVOC emissions and fires. We use a 3-D chemical transport model (GEOS-Chem) constrained by a global suite of observations to evaluate the sources and significance of PAN. We quantify individual NMVOC and NOX contributions to PAN formation, and we identify where PAN has a significant impact on remote O3, OH and nitrogen deposition. We find that a simulation with improved budgets for key NMVOCs (ethane, acetaldehyde, ethanol, acetone and select aromatic species) is able to reproduce the main features of the global PAN distribution. We also show that the treatment of PAN formation in fires plays an important role in determining the global impact of this PAN source. The contributions of acetaldehyde, acetone and methylglyoxal to PAN formation reflect the sources and lifetimes of these immediate precursors. Acetaldehyde, which is emitted directly from biogenic sources and formed via hydrocarbon oxidation, is the most important peroxyacetyl radical precursor globally. Methylglyoxal, an oxidation product of both isoprene and aromatic species, is responsible for about a third of peroxyactyl radical formation in the lower troposphere. Isoprene oxidation products, other than methylglyoxal, are also significant for the global PAN budget. With updated (lower) photolysis yields, acetone is less important for PAN formation than previously thought. It is responsible for less peroxyactyl radical formation globally than each of the other immediate precursors below 200 hPa. Lightning contributes to a uniform upper tropospheric PAN distribution in the southern hemisphere tropics where it is the most important NOx source for PAN formation. We estimate that PAN acts to increase lower tropospheric summertime O3 over the remote oceans by ~15% at mid-latitudes. The impact of PAN on remote OH is complex. The direction and magnitude of the impact varies geographically and vertically.

Fischer, E. V.; Jacob, D. J.; Yantosca, R. M.; Payer, M.

2012-12-01

298

Evaporation control research, 1959-60  

USGS Publications Warehouse

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

U.S. Geological Survey

1963-01-01

299

PanSNPdb: The Pan-Asian SNP Genotyping Database Chumpol Ngamphiw1,2  

E-print Network

Institute of Bioscience and Biotechnology (KRIBB), Yuseong-gu, Deajeon, South Korea, 5 Personal Genomics Institute, Genome Research Foundation, Suwon, South Korea, 6 Theragen BiO Institute, TheragenEtex, Suwon, South Korea, 7 Genome Institute of Singapore, Singapore, Singapore Abstract The HUGO Pan-Asian SNP

Xu, Shuhua

300

Transient Detections from Pan-STARRS  

NASA Astrophysics Data System (ADS)

The first Pan-STARRS telescope, PS1, is now collecting survey data on a nightly basis, for the first time producing new transient detections. One of the primary branches of the PS1 science strategy is the Medium Deep survey, which will detect thousands of supernovae and other explosive transients. This extraordinary yield from a single survey will allow us to put new constraints on the nature of Dark Energy and to improve our understanding of the progenitor systems that produce Type Ia Supernovae. We present early detections from the Fall 2008 PS1 campaign.

Rodney, Steven A.

2009-01-01

301

Development of a Water Cluster Evaporation Model using Molecular Dynamics  

NASA Astrophysics Data System (ADS)

A Monte Carlo simulation using the SPC potential model has been used to determine the potential energy and constant volume heat capacity of water dimers and trimers. It was found that the potential energy almost follows a linear trend versus temperature. The heat capacity fluctuates around 10 cal/mol/K and reaches a maximum around 220 K for the dimer and 240 K for the trimer. The Molecular Dynamics simulation has been used to evaporate water dimers and trimers. The cumulative evaporation probabilities were calculated for temperatures ranging from 240 K to 300 K. The cluster evaporation rates were calculated using Weerashinge's equation, and they were compared with the UDT rates. Both values were found to be in good agreement. Finally, vibrational frequencies were computed.

Borner, Arnaud; Li, Zheng; Levin, Deborah A.

2011-05-01

302

Evaporation from weighing precipitation gauges: impacts on automated gauge measurements and quality assurance methods  

NASA Astrophysics Data System (ADS)

The effects of evaporation on precipitation measurements have been understood to bias total precipitation lower. For automated weighing-bucket gauges, the World Meteorological Organization (WMO) suggests the use of evaporative suppressants with frequent observations. However, the use of evaporation suppressants is not always feasible due to environmental hazards and the added cost of maintenance, transport, and disposal of the gauge additive. In addition, research has suggested that evaporation prior to precipitation may affect precipitation measurements from auto-recording gauges operating at sub-hourly frequencies. For further evaluation, a field campaign was conducted to monitor evaporation and its impacts on the quality of precipitation measurements from gauges used at US Climate Reference Network (USCRN) stations. Collocated Geonor gauges with (nonEvap) and without (evap) an evaporative suppressant were compared to evaluate evaporative losses and evaporation biases on precipitation measurements. From June to August, evaporative losses from the evap gauge exceeded accumulated precipitation, with an average loss of 0.12 mm h-1. However, the impact of evaporation on precipitation measurements was sensitive to calculation methods. In general, methods that utilized a longer time series to smooth out sensor noise were more sensitive to gauge (-4.6% bias with respect to control) evaporation than methods computing depth change without smoothing (< +1% bias). These results indicate that while climate and gauge design affect gauge evaporation rates computational methods can influence the magnitude of evaporation bias on precipitation measurements. It is hoped this study will advance QA techniques that mitigate the impact of evaporation biases on precipitation measurements from other automated networks.

Leeper, R. D.; Kochendorfer, J.

2014-12-01

303

Transpiration and evaporation from heather Moorland  

NASA Astrophysics Data System (ADS)

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

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

1984-03-01

304

Characteristic behavior of peroxyacetyl nitrate (PAN) in Seoul megacity, Korea.  

PubMed

We measured the concentrations of peroxyacetyl nitrate (PAN) and other photochemically reactive species, including O3, NO2, and non-methane hydrocarbons (NMHCs), in the Seoul Metropolitan area (SMA) during May through June in 2004 and 2005. PAN was determined using a fast chromatograph with luminol-based chemiluminescence detection. Mixing ratios of PAN ranged from below the detection limit (0.1ppbv) to 10.4ppbv with an average of 0.8ppbv. O3 concentrations ranged from 0 to 141ppbv. The average PAN/O3 ratio of 0.07 was higher than that observed in cities of Europe and North America (0.02) where control strategies have been enforced to reduce hydrocarbon emissions through extensively reformulated gasoline programs. Strong positive correlations between daily PAN and O3 maxima during the day demonstrate that similar photochemical factors controlled the production of these two chemicals. However, relationships between PAN and its precursors, NO2 and NMHCs, suggest that PAN production was more sensitive to NO2 than NMHCs levels whereas O3 production was limited by the overall availability of NMHCs. It is likely that the compositions of NMHCs in SMA were favorable for PAN production because of the low fractions of oxygenated compounds in automobile fuels. PAN maxima were observed around noon, which was 2-3h earlier than the much broader O3 maxima that occurred in the midafternoon. After reaching the maximum, PAN concentrations rapidly dropped within a few hours, which could be largely due to thermal destruction and to limited production under the typically low NO2 levels that occurred in the early afternoon. The heterogeneous destruction of particulate matter could be an additional sink for PAN in SMA. PMID:18632134

Lee, Gangwoong; Jang, Yuwoon; Lee, Heayoung; Han, Jin-Seok; Kim, Kyung-Ryul; Lee, Meehye

2008-09-01

305

Evaporation Estimation of Rift Valley Lakes: Comparison of Models  

PubMed Central

Evapotranspiration (ET) accounts for a substantial amount of the water flux in the arid and semi-arid regions of the World. Accurate estimation of ET has been a challenge for hydrologists, mainly because of the spatiotemporal variability of the environmental and physical parameters governing the latent heat flux. In addition, most available ET models depend on intensive meteorological information for ET estimation. Such data are not available at the desired spatial and temporal scales in less developed and remote parts of the world. This limitation has necessitated the development of simple models that are less data intensive and provide ET estimates with acceptable level of accuracy. Remote sensing approach can also be applied to large areas where meteorological data are not available and field scale data collection is costly, time consuming and difficult. In areas like the Rift Valley regions of Ethiopia, the applicability of the Simple Method (Abtew Method) of lake evaporation estimation and surface energy balance approach using remote sensing was studied. The Simple Method and a remote sensing-based lake evaporation estimates were compared to the Penman, Energy balance, Pan, Radiation and Complementary Relationship Lake Evaporation (CRLE) methods applied in the region. Results indicate a good correspondence of the models outputs to that of the above methods. Comparison of the 1986 and 2000 monthly lake ET from the Landsat images to the Simple and Penman Methods show that the remote sensing and surface energy balance approach is promising for large scale applications to understand the spatial variation of the latent heat flux. PMID:22303142

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

2009-01-01

306

Evaporation from Lake Mead, Arizona and Nevada, 1997-99  

USGS Publications Warehouse

Lake Mead is one of a series of large Colorado River reservoirs operated and maintained by the Bureau of Reclamation. The Colorado River system of reservoirs and diversions is an important source of water for millions of people in seven Western States and Mexico. The U.S. Geological Survey, in cooperation with the Bureau of Reclamation, conducted a study from 1997 to 1999 to estimate evaporation from Lake Mead. For this study, micrometeorological and hydrologic data were collected continually from instrumented platforms deployed at four locations on the lake, open-water areas of Boulder Basin, Virgin Basin, and Overton Arm and a protected cove in Boulder Basin. Data collected at the platforms were used to estimate Lake Mead evaporation by solving an energy-budget equation. The average annual evaporation rate at open-water stations from January 1998 to December 1999 was 7.5 feet. Because the spatial variation of monthly and annual evaporation rates was minimal for the open-water stations, a single open-water station in Boulder Basin would provide data that are adequate to estimate evaporation from Lake Mead.

Westenburg, Craig L.; DeMeo, Guy A.; Tanko, Daron J.

2006-01-01

307

Ratosa playa lake in southern Spain. Karst pan or compound sink?  

PubMed

In Andalusia (Spain), there are more than 45 semiarid playa lakes protected as natural reserves and related to karstic outcrops. Some of them are located over regional karstic aquifers and have internal drainage networks with sporadic surface outlets, such as sinkholes (compound sinks), but the majority of such playas have no internal drainage systems, so the only water output is evaporation (karst pans). Karst pans are perched and disconnected from the groundwater system. The fact that the Ratosa playa lake is partially located over a karstic Sierra, as well as other hydromorphological observations, it is suggested that the system could be of a compound type, but a detailed hydrogeological analysis showed that the playa is disconnected from the aquifer, so it is in fact a karst pan. Once the hydrological functioning had been established, a monthly water balance for a 10-year period (1998-2008), enabled us to reproduce the evolution of the water level of the playa lake. Estimations of runoff were carried out by a soil water estimate for a water holding capacity in the soil of 191 mm. Results show a good correlation (>90 %) after calibration with the time series of water level in the lake for the same period confirming geological observations. Our results highlight that this water body is extremely vulnerable to hydrological alterations of its watershed caused by human activities, particularly those related to land-use change for agriculture. For this reason, we propose a new protection zone, based on hydrological knowledge, instead of the present Peripheral Area of Protection. PMID:25810083

Rodríguez-Rodríguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio; Benavente-Herrera, José

2015-04-01

308

The Salmonella enterica pan-genome.  

PubMed

Salmonella enterica is divided into four subspecies containing a large number of different serovars, several of which are important zoonotic pathogens and some show a high degree of host specificity or host preference. We compare 45 sequenced S. enterica genomes that are publicly available (22 complete and 23 draft genome sequences). Of these, 35 were found to be of sufficiently good quality to allow a detailed analysis, along with two Escherichia coli strains (K-12 substr. DH10B and the avian pathogenic E. coli (APEC O1) strain). All genomes were subjected to standardized gene finding, and the core and pan-genome of Salmonella were estimated to be around 2,800 and 10,000 gene families, respectively. The constructed pan-genomic dendrograms suggest that gene content is often, but not uniformly correlated to serotype. Any given Salmonella strain has a large stable core, whilst there is an abundance of accessory genes, including the Salmonella pathogenicity islands (SPIs), transposable elements, phages, and plasmid DNA. We visualize conservation in the genomes in relation to chromosomal location and DNA structural features and find that variation in gene content is localized in a selection of variable genomic regions or islands. These include the SPIs but also encompass phage insertion sites and transposable elements. The islands were typically well conserved in several, but not all, isolates--a difference which may have implications in, e.g., host specificity. PMID:21643699

Jacobsen, Annika; Hendriksen, Rene S; Aaresturp, Frank M; Ussery, David W; Friis, Carsten

2011-10-01

309

Biogeomorphically driven salt pan formation in Sarcocornia-dominated salt-marshes  

NASA Astrophysics Data System (ADS)

Salt-marshes are under increasing threat, particularly from sea-level rise and increased wave action associated with climate change. The development and stability of these valuable habitats largely depend on complex interactions between biotic and abiotic processes operating at different scales. Also, interactions between biotic and abiotic processes drive internal morphological change in salt-marshes. In this paper we used a biogeomorphological approach to assess the impact of biological activities and interactions on salt pan formation in Sarcocornia-dominated salt marshes. Salt pans represent a key physiographic feature of salt-marshes and recent studies hypothesized that biogeomorphic processes could be related to salt pan formation in SW Atlantic salt-marshes. The glasswort Sarcocornia perennis is one of the dominant plants in the salt-marshes of the Bahía Blanca Estuary (Argentina) where they form patches up to 8 m in diameter. These salt-marshes are also inhabited in great densities by the burrowing crab Neohelice (Chasmagnathus) granulata whose bioturbation rates are among the highest reported for salt-marshes worldwide. A set of biological interactions between N. granulata and S. perennis appears to be responsible for salt pan development in these areas which has not been described elsewhere. The main objective of this work was to determine the ecological interactions occurring between plants and crabs that lead to salt pan formation by using field-based sampling and manipulative experiments. Our results showed that S. perennis facilitated crab colonization of the salt-marsh by buffering otherwise stressful physical conditions (e.g., temperature, desiccation). Crabs preferred to construct burrows underneath plants and, once they reach high densities (up to 40 burrows m- 2), the sediment reworking caused plant die-off in the central area of patches. At this state, the patches lose elevation and become depressed due to the continuous bioturbation by crabs. Thus, salt pans are generated in this case by a set of biogeomorphic processes that include pure ecological interactions such as plant facilitation of crab settlement and also indirect negative effects of crabs on plant survival. Furthermore, crab bioturbation affects sediment structure due to concentration of burrowing activity under plant canopies promoting elevation loss and leading, after a few years, to salt pan formation in a previously vegetated substrate.

Escapa, Mauricio; Perillo, Gerardo M. E.; Iribarne, Oscar

2015-01-01

310

Membrane evaporator/sublimator investigation  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

311

Color Evaporation Induced Rapidity Gaps  

E-print Network

We show that soft color rearrangement of final states can account for the appearance of rapidity gaps between jets. In the color evaporation model the probability to form a gap is simply determined by the color multiplicity of the final state. This model has no free parameters and reproduces all data obtained by the ZEUS, H1, D0, and CDF collaborations.

O. J. P. Eboli; E. M. Gregores; F. Halzen

1999-08-16

312

Evaporative cooling of speleothem drip water  

PubMed Central

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

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

2014-01-01

313

VIGNETTING CORRECTION FOR PAN-TILT SURVEILLANCE CAMERAS  

E-print Network

VIGNETTING CORRECTION FOR PAN-TILT SURVEILLANCE CAMERAS Ricardo Galego, Alexandre Bernardino, Jos-tilt cameras, with applications to visual surveillance in a cube (mosaicked) visual field representation.galego@gmail.com, {alex,jag}@isr.ist.utl.pt Keywords: Image formation, Vignetting correction, Pan-Tilt cameras, Visual

Instituto de Sistemas e Robotica

314

Detecting Earth-impacting asteroids Pan-STARRS prototype telescope  

E-print Network

Detecting Earth-impacting asteroids with the Pan-STARRS prototype telescope (Based on MS. Grav #12;10/14/2008 DPS, Ithaca, NY Granvik: Earth-impacting asteroids with PS1 Pan-STARRS 1 (PS1) Moving Object Processing System (MOPS) #12;10/14/2008 DPS, Ithaca, NY Granvik: Earth-impacting asteroids

Veres, Peter

315

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

316

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

317

On the evaporation of ammonium sulfate solution Walter S. Drisdella,b  

E-print Network

On the evaporation of ammonium sulfate solution Walter S. Drisdella,b , Richard J. Saykallya climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via aqueous ammonium sulfate, which is the most abun- dant inorganic component of atmospheric aerosol, does

Cohen, Ronald C.

318

Study of water evaporation and condensation in a domestic refrigerator loaded by wet product  

Microsoft Academic Search

This study was carried out to gain a better insight into evaporation and condensation phenomena due to natural convection in a domestic refrigerator. An experiment was undertaken in a refrigerator loaded with 40humid plaster cylinders (50mm diameter). The weight variation of the cylinders was followed over 12days and the rate of water evaporation (or condensation for some cylinders) was calculated.

O. Laguerre; S. Benamara; D. Flick

2010-01-01

319

Analysis of defrosted water evaporation from three water trays in refrigerators  

Microsoft Academic Search

The evaporation of defrosted water from vapour compression domestic refrigerators can be a real problem in tropical countries with hot and humid ambient conditions. This poses a challenge to the refrigerator manufacturers to design a water tray with minimal additional cost but with significantly improved evaporation rates. This paper, therefore, analyses the performance of three types of water trays that

G. Xie; P. K. Bansal

2000-01-01

320

REAR-SIDE POINT-CONTACTS BY INLINE THERMAL EVAPORATION OF ALUMINUM Christoph Mader  

E-print Network

REAR-SIDE POINT-CONTACTS BY INLINE THERMAL EVAPORATION OF ALUMINUM Christoph Mader 1 , Jens Müller of point-contacted aluminum rear-sides for silicon solar cells that are metalized by inline thermal evaporation. We deposit aluminum layers of 2 µm thickness at dynamic deposition rates of 1.0, 2.9 and 5.0 µm

321

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

Microsoft Academic Search

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

K. Ozawa; H. Nagahara

2009-01-01

322

Is the evaporation water loss of Knot Calidris canutus higher in tropical than in temperate climates?  

Microsoft Academic Search

To test whether Knot Calidris canutus wintering in the tropics suffer higher rates of water loss through evaporation than do Knot wintering at temperate latitudes, we tried to develop a physically realistic model to predict evaporative heat loss from air temperature, wind and humidity. In separate experiments, involving respirometry and double-labelled water, we tried to estimate relevant parameters, In both

N. Verboven; T. Piersma

1995-01-01

323

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

PubMed Central

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

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

2014-01-01

324

A diagram for the evaporation status of extrasolar planets  

E-print Network

To describe the evaporation status of the extrasolar planets, we propose to consider an energy diagram in which the potential energy of the planets is plotted versus the energy received by the upper atmosphere. Here we present a basic method to estimate these quantities. For the potential energy, we include the modification of the gravity field by the tidal forces from the parent stars. This description allows a quick estimate of both the escape rate of the atmospheric gas and the lifetime of a planet against the evaporation process. In the energy diagram, we find an evaporation-forbidden region in which a gaseous planet would evaporate in less than 5 billion years. With their observed characteristics, all extrasolar planets are found outside this evaporation-forbidden region. The escape rates are estimated to be in the range 10^5 g/s to 10^{12} g/s, with few cases above 10^{11} g/s. The estimated escape rate for HD209458b is found to be consistent with the lower limit of 10^{10} g/s obtained from interpretation of the HI Lyman-alpha observations. Finally, this diagram suggests possibilities for the nature of the recently discovered Neptune-mass planets. We find that GJ436b, 55Cnc_e and HD69830b cannot be low mass gaseous planets. With density necessarily above 0.5g/cm3 to survive evaporation, these planets must contain a large fraction of solid/liquid material. Concerning GJ876d, we find that it must have a density larger than ~3g/cm3 to survive the strong EUV energy flux from its nearby parent star. GJ876d must contain a large fraction of massive elements.

A. Lecavelier des Etangs

2006-09-27

325

21 CFR 131.130 - Evaporated milk.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Evaporated milk. 131.130 Section 131.130 Food and...CONTINUED) FOOD FOR HUMAN CONSUMPTION MILK AND CREAM Requirements for Specific Standardized Milk and Cream § 131.130 Evaporated...

2013-04-01

326

Analysis of the e-beam evaporation of titanium and Ti-6Al-4V  

SciTech Connect

An experimental and finite element analysis was performed for the electron-beam evaporation of Ti and Ti-6Al-4V from a bottom-feed system. The bulk evaporation rate was measured by feed consumption, and the pool elevation was held constant by adjusting the feed rate in a closed-loop control system. The instantaneous titanium and aluminum evaporation rates were determined by laser absorption in the vapor plume. Water temperature rises in cooling water circuits provided heat flows, and post-run cross sections revealed the location of the solidification zone. The MELT finite element code was applied to model the steady-state two-dimensional fluid flow and energy transport in the rod. There was good agreement between model and measured values of the heat flows and solidification boundaries for Ti. Measured bulk evaporation rates were similar for Ti and Ti-6-4 with greater variation observed for the Ti values. The model evaporation rates were higher than the measured values, but a similar linear dependence on e-beam power was observed in all cases. In a Ti-6-4 evaporation experiment with steady process conditions, laser absorption measurements showed much larger fluctuations in the evaporation rate for Al than Ti.

Westerberg, K.W.; Merier, T.C.; McClelland, M.A.; Braun, D.G.; Berzins, L.V.; Anklam, T.M.; Storer, J.

1998-02-11

327

Collective Difference: The Pan-American Association of Composers and Pan-American Ideology in Music, 1925-1945  

Microsoft Academic Search

This dissertation probes the relationship between Pan-Americanism and musical production in its cultural and historic context through close analysis of the music, concert programming, and publications of the Pan-American Association of Composers. The PAAC presented concerts of new music from the Americas between 1928 and 1934 in New York City, Havana, and Europe. Purposeful diversity, or “collective difference,” was the

Stephanie N. Stallings

2009-01-01

328

Inferences About the Location of Food in the Great Apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus )  

Microsoft Academic Search

Bonobos (Pan paniscus; n = 4), chimpanzees (Pan troglodytes; n = 12), gorillas (Gorilla gorilla; n = 8), and orangutans (Pongo pygmaeus; n = 6) were presented with 2 cups (1 baited) and given visual or auditory information about their contents. Visual information consisted of letting subjects look inside the cups. Auditory information consisted of shaking the cup so that

Josep Call

2004-01-01

329

The role of evaporation in spatiotemporal variability of beach surface moisture  

NASA Astrophysics Data System (ADS)

Surficial moisture is a critical control of aeolian sediment transport on sandy beaches. Several recent studies have monitored meso-scale spatiotemporal trends in beach surface moisture, but do not provide a strong basis for linking trends to underlying processes. Previous research has modeled tidal forcing on water table elevation in beaches, and some data are available on capillary moisture dynamics above the water table. Few data are available, however, on the relative role of atmospheric vs. groundwater processes in beach surface moisture variability. This paper presents results from two field studies designed to quantify evaporation from a fine-grained beach and model the surface energy budget. Atmospheric fluxes were measured using the Bowen ratio energy balance method and a modified Bowen ratio energy balance method (using sensible heat flux measurements from a sonic anemometer). Evaporation estimates were also made using a standard USDA evaporation pan and a series of pans (isolated from groundwater) containing saturated sediment samples (6 cm deep) in the beach face, and changes in the natural surface moisture were recorded from surface scrapings. Stable isotope analysis was conducted on soil water samples collected periodically in a profile from the water table to the surface. Results suggest that evaporation from the beach surface is a strong control on surface moisture when the water table is low, but high water tables maintain surface moisture by capillary rise. Thus, periodicity of water table fluctuations with respect to day/night energy availability is a key predictor of moisture at the surface, especially in the absence of significant precipitation.

Edwards, B. L.; Namikas, S. L.; Keim, R.

2013-12-01

330

Clinical Evaluation of Youth with Pediatric Acute-Onset Neuropsychiatric Syndrome (PANS): Recommendations from the 2013 PANS Consensus Conference.  

PubMed

On May 23 and 24, 2013, the First PANS Consensus Conference was convened at Stanford University, calling together a geographically diverse group of clinicians and researchers from complementary fields of pediatrics: General and developmental pediatrics, infectious diseases, immunology, rheumatology, neurology, and child psychiatry. Participants were academicians with clinical and research interests in pediatric autoimmune neuropsychiatric disorder associated with streptococcus (PANDAS) in youth, and the larger category of pediatric acute-onset neuropsychiatric syndrome (PANS). The goals were to clarify the diagnostic boundaries of PANS, to develop systematic strategies for evaluation of suspected PANS cases, and to set forth the most urgently needed studies in this field. Presented here is a consensus statement proposing recommendations for the diagnostic evaluation of youth presenting with PANS. PMID:25325534

Chang, Kiki; Frankovich, Jennifer; Cooperstock, Michael; Cunningham, Madeleine W; Latimer, M Elizabeth; Murphy, Tanya K; Pasternack, Mark; Thienemann, Margo; Williams, Kyle; Walter, Jolan; Swedo, Susan E

2015-02-01

331

Evaporation of Molten Salts by Plasma Torch  

NASA Astrophysics Data System (ADS)

Archimedes Technology Group is developing a plasma nuclear waste separation technology, called the Plasma Mass Filter. The experimental results on thermal evaporation of molten NaOH based surrogates for the Filter are presented. The main goal of the experiments was the study of high-density plasma discharges in NaOH vapor with the aim to minimize injection of additional working gas in the plasma torch. In these experiments NaOH vapor has been produced either by evaporation of the melt from a crucible introduced inside the plasma torch, or by injection of the melt droplets inside the torch. In the latter case, the melt was first atomized by an ultrasonic nebulizer at a flow rate of up to 2g/s with a droplet size of ˜50um. Plasma composition has been monitored by optical measurements. An optical diagnostic for droplet size measurement is presented together with results of the measurements of the size spectrum of the NaOH droplets.

Putvinski, S.; Agnew, S. F.; Chamberlain, F.; Freeman, R. L.; Litvak, A.; Meekins, M.; Schwedock, T.; Umstadter, K. R.; Yung, S.; Bakharev, V.; Dresvin, S.; Egorov, S.; Feygenson, O.; Gabdullin, P.; Ivanov; Kizevetter, D.; Kostrukov, A.; Kuteev, B.; Malugin, V.; Zverev, S.

2003-10-01

332

Influence of Oil on Refrigerant Evaporator Performance  

NASA Astrophysics Data System (ADS)

To explore the quantitative effect of the lubrication oil on the thermal and hydraulic evaporator performance, the detailed structure of two-phase refrigerant (R11) and lubrication oil (Suniso 5GS) flow has been investigated. Experiment has been performed using a transparent tube 20mm in inner diameter and 2600mm in total length as main test section, which was heated by surrounding hot water bath. This water bath also functioned as the visual observation section of the transition of two-phase flow pattern. Oil mass concentration was controlled initially, and circulated into the system. The void fraction at the main test section was measured by direct volume measurement using so-called "Quick Closing Valve" method. Since the effect of oil on the transition of two-phase flow pattern is emphasized at the low flow rate, operation was made at relatively low mass velocity, 50 and 100 kg/m2·s, five different oil concentrations were taken. Throughout the experiment, the evaporation pressure was kept at 105 kPa. In general, when contamination of the lubrication oil happened, the void fraction was decreasing due to the change of viscosity and surface tension and the occurence of the foaming. To correlate the void fraction as function of quality, Zivi's expression was modified to include the effect of oil concentration. The agreement between the data and this proposed correlation was favorable. Finally, to take into account the effect of lubrication oil, the new flow pattern diagram was proposed.

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

333

Multispectral remote sensing contribution to land surface evaporation  

NASA Technical Reports Server (NTRS)

The global water cycle is perhaps the most important of all the biogeochemical cycles and evaporation, which is a significant component of the water cycle, is also linked with the energy and carbon cycles. Long-term evaporation over large areas has generally been computed as the difference of precipitation and river runoff. Analysis of short-term evaporation rate and its spatial pattern, however, is extremely complex, and multispectral remotely sensed data could aid in such analysis. Multispectral data considered here are visible and near-infrared reflectances, infrared surface temperature and the 37 GHz brightness temperatures. These observations are found to be not totally independent of each other. A few of their relationships are established and discussed considering physically-based models.

Choudhury, B. J.

1990-01-01

334

Negative pressure characteristics of an evaporating meniscus at nanoscale.  

PubMed

This study aims at understanding the characteristics of negative liquid pressures at the nanoscale using molecular dynamics simulation. A nano-meniscus is formed by placing liquid argon on a platinum wall between two nano-channels filled with the same liquid. Evaporation is simulated in the meniscus by increasing the temperature of the platinum wall for two different cases. Non-evaporating films are obtained at the center of the meniscus. The liquid film in the non-evaporating and adjacent regions is found to be under high absolute negative pressures. Cavitation cannot occur in these regions as the capillary height is smaller than the critical cavitation radius. Factors which determine the critical film thickness for rupture are discussed. Thus, high negative liquid pressures can be stable at the nanoscale, and utilized to create passive pumping devices as well as significantly enhance heat transfer rates. PMID:21711621

Maroo, Shalabh C; Chung, Jn

2011-01-01

335

SEWAGE DISPOSAL BY EVAPORATION-TRANSPIRATION  

EPA Science Inventory

One of the methods for on-site disposal of wastewater from individual homes is by evaporation. Two types of evaporative disposal systems have been investigated in this study; evapo-transpiration (ET) beds and mechanical evaporation units. Twenty nine test lysimeters of 0.22 cubic...

336

Improved Evaporation Measurements from Lake Tahoe, California  

Microsoft Academic Search

Accurate measurements of evaporation are important to management of water storage as well as to understanding turnover and nutrient storage in lakes. Evaporation has been a poorly constrained component of past water budget studies of Lake Tahoe, California and is the last major unknown for effective management of the Truckee River basin under the Truckee River Operating Agreement (TROA). Evaporation

G. L. Dana; J. C. Trask

2001-01-01

337

Black Hole Evaporation as a Nonequilibrium Process  

Microsoft Academic Search

When a black hole evaporates, there arises a net energy flow from the black hole into its outside environment due to the Hawking radiation and the energy accretion onto black hole. Exactly speaking, due to the net energy flow, the black hole evaporation is a nonequilibrium process. To study details of evaporation process, nonequilibrium effects of the net energy flow

Hiromi Saida

2008-01-01

338

Apparatus and method for evaporator defrosting  

Microsoft Academic Search

An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second

Viung C. Mei; Fang C. Chen; Ronald E. Domitrovic

2001-01-01

339

Tank 26 Evaporator Feed Pump Transfer Analysis  

Microsoft Academic Search

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the

David Tamburello; Richard Dimenna; Si Lee

2009-01-01

340

TANK 26 EVAPORATOR FEED PUMP TRANSFER ANALYSIS  

Microsoft Academic Search

The transfer of liquid salt solution from Tank 26 to an evaporator is to be accomplished by activating the evaporator feed pump, located approximately 72 inches above the sludge layer, while simultaneously turning on the downcomer. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the

D Tamburello; S Si Lee; R Richard Dimenna

2008-01-01

341

Evaporation as the transport mechanism of metals in arid regions.  

PubMed

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

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

2014-09-01

342

Study of evaporating droplet temperature in low pressure plasma  

NASA Astrophysics Data System (ADS)

A key parameter of misty plasmas is the temperature (Td) of the liquid droplets in the plasma. Td determines the rate at which droplets evaporate and is a consequence of the energy balance between plasma species which bring thermal energy and droplet evaporative cooling. We are using Rhodamine B (RhB) to estimate Td because the spectrum of this dye is known to be Td dependent. For example: RhB has been used to study the temperature of dust in plasmas and fuel droplets in combustion. A complication is that there are at least two major differences between dust particles and liquid droplets in plasmas: [1] droplets evaporate which changes their RhB concentration in time and [2] droplets are expected to be as much as 150 C cooler than dust grains. Both make calibration more difficult. In this poster, we will present our progress in using this technique to estimate the temperature of evaporating droplets in low pressure plasma. This will include our calibration procedures, the RhB spectral dependencies (concentration, and T) and measurements of both droplet evaporation kinetics as well as RhB spectra in vacuum and plasma.

Ogawa, Daisuke; Goeckner, Matthew; Overzet, Lawrence

2011-11-01

343

Influence of electron evaporative cooling on ultracold plasma expansion  

SciTech Connect

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

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

2013-07-15

344

Hydrodynamics and evaporation of a sessile drop of capillary size  

NASA Astrophysics Data System (ADS)

Several dynamical stages of the Marangoni convection of an evaporating sessile drop are obtained. We jointly take into account the hydrodynamics of an evaporating sessile drop, effects of the thermal conduction in the drop and the diffusion of vapor in air. The stages are characterized by different number of vortices in the drop and the spatial location of vortices. During the early stage the array of vortices arises near a surface of the drop and induces a non-monotonic spatial distribution of the temperature over the drop surface. The number of near-surface vortices in the drop is controlled by the Marangoni cell size, which is calculated similar to that given by Pearson for flat fluid layers. The number of vortices quickly decreases with time, resulting in three bulk vortices in the intermediate stage. The vortex structure finally evolves into the single convection vortex in the drop, existing during about 1/2 of the evaporation time. Simulation results agree well with the data of evaporation rate measurements for the toluene drop. Computed dependence of contact angle of colloidal sessile droplet during evaporation coincide well with available experimental time dependence of angle of nanocrystal superlattice domains orientation.

Barash, Lev; Bigioni, Terry; Vinokur, Valerii; Shchur, Lev

2010-11-01

345

Evaporation Mechanism of Sn and SnS from Liquid Fe: Part II: Residual Site and Evaporation Kinetics via Sn(g) and SnS(g)  

NASA Astrophysics Data System (ADS)

Evaporation of Sn from molten steel was experimentally investigated for Fe-Sn-S alloy with low initial S (0.0007 < [pct S]0 < 0.05) or with high initial S (0.55 < [pct S]0 < 0.894) at 1873 K (1600 °C) using an electromagnetic levitation melting technique, in order to clarify the role of S on the evaporation mechanism of Sn. It was found that increasing initial S concentration, [pct S]0, decreased the second-order evaporation rate constant of Sn ( k SnS), but there was a residual rate for the evaporation even at high [pct S]0. The obtained residual rate constant, , was 1.4 × 10-9 m4 mol-1 s-1 at 1873 K (1600 °C). Evaporation of Sn under virtually no S condition ([pct S]0 = 0.0007) was also measured and corresponding first-order rate constant was determined to be 3.49 × 10-7 m s-1 at 1873 K (1600 °C). A comprehensive model for the Sn evaporation from molten Fe-Sn-S alloy was developed in the present study, under the condition where mass transfer in gas and liquid phases were fast and interfacial chemical reaction controlled the evaporation of Sn. The model equation is able to represent the evaporation of Sn in the forms of Sn(g) and SnS(g) simultaneously, from very low S melt (when there is no S) to very high S melt investigated in the present study up to ~0.9 mass pct. Gradual transition of major evaporation species from SnS(g) to Sn(g) was well accounted for by the developed model.

Jung, Sung-Hoon; Kang, Youn-Bae; Seo, Jeong-Do; Park, Joong-Kil; Choi, Joo

2015-02-01

346

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

PubMed Central

Pancreatic cancer is still a dismal disease. The high mortality rate is mainly caused by the lack of highly sensitive and specific diagnostic tools, and most of the patients are diagnosed in an advanced and incurable stage. Knowledge about precursor lesions for pancreatic cancer has grown significantly over the last decade, and nowadays we know that mainly three lesions (PanIN, and IPMN, MCN) are responsible for the development of pancreatic cancer. The early detection of these lesions is still challenging but provides the chance to cure patients before they might get an invasive pancreatic carcinoma. This paper focuses on PanIN, IPMN, and MCN lesions and reviews the current level of knowledge and clinical measures. PMID:24783207

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

2014-01-01

347

An energy partition evaporation recorder  

Microsoft Academic Search

A description is given of an instrument which provides a near-continuous measurement of evaporation from natural surfaces. This instrument employs a resistive bridge technique to sense net radiation, ambient wet-bulb temperature and dry- and wet-bulb temperature differences, and employs a servobalance system to combine the corresponding electrical signals according to a modified version of the energy balance formula. Details are

A. C. Dilley

1974-01-01

348

Evaporation by mechanical vapor recompression  

NASA Astrophysics Data System (ADS)

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

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

1980-04-01

349

Pan-sharpening high spatial resolution ratio images using optimization  

NASA Astrophysics Data System (ADS)

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

Li, Fangjun; Chen, Fu; Liu, Jianbo

2009-10-01

350

Summertime PAN on boundary layer over the Northern Pacific Ocean  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

351

Pan1 is an intrinsically disordered protein with homotypic interactions  

PubMed Central

The yeast scaffold protein Pan1 contains two EH domains at its N-terminus, a predicted coiled-coil central region, and a C-terminal proline-rich domain. Pan1 is also predicted to contain regions of intrinsic disorder, characteristic of proteins that have many binding partners. In vitro biochemical data suggest that Pan1 exists as a dimer, and we have identified amino acids 705–848 as critical for this homotypic interaction. Tryptophan fluorescence was used to further characterize Pan1 conformational states. Pan1 contains four endogenous tryptophans, each in a distinct region of the protein: Trp312 and Trp642 are each in an EH domain, Trp957 is in the central region, and Trp1280 is a critical residue in the Arp2/3 activation domain. To examine the local environment of each of these tryptophans, three of the four tryptophans were mutagenized to phenylalanine to create four proteins, each with only one tryptophan residue. When quenched with acrylamide, these single tryptophan mutants appeared to undergo collisional quenching exclusively and were moderately accessible to the acrylamide molecule. Quenching with iodide or cesium, however, revealed different Stern-Volmer constants due to unique electrostatic environments of the tryptophan residues. Time-resolved fluorescence anisotropy data confirmed structural and disorder predictions of Pan1. Further experimentation to fully develop a model of Pan1 conformational dynamics will assist in a deeper understanding of the mechanisms of endocytosis. PMID:23801378

Pierce, B. D.; Toptygin, D.; Wendland, B.

2013-01-01

352

Effect of soil type patterns on the variability of bare soil evaporation within a field: comparison of eddy covariance measurements with potential and actual evaporation calculations  

NASA Astrophysics Data System (ADS)

Bare soil evaporation was measured with the eddy-covariance method at the Selhausen field site. The site has a distinct gradient in soil texture with a considerably higher stone content at the upper part of the field. Because of this gradient, a spatial variation in evaporation fluxes in the field is expected. Because of the higher stone content at the upper part of the field, it is expected that the water that is stored in the soil surface layer and can be evaporated at a maximal evaporation rate, which is determined by the energy that is available for evaporation, is considerable smaller in the upper than in the lower part of the field. We investigated whether this hypothesis is supported by eddy covariance (EC) measurements of the evaporation fluxes at the field site. The EC measurements were combined with a footprint model that predicts the location of the soil surface that contributes to the measured evaporation flux. In this way, evaporation measurements of the two parts of the field site could be distinguished. However, since only one EC station was available, simultaneous evaporation measurements for the two field parts were not available. As a consequence, the datasets of measurements had to be interpreted and put into context of the meteorological and soil hydrological conditions. The potential evapotranspiration was calculated using the FAO method (Allen et al., 1998) to represent the meteorological conditions whereas a simple soil evaporation model (Boesten and Stroosnijder, 1986) was used to represent the influence of the precipitation and soil hydrological conditions on the actual evaporation rate. Since different soil parameters were required to describe the evaporation measurements for the upper and lower part of the plot, our starting hypothesis that more water is evaporated in the lower part of the field could be confirmed. Allen, R. G., L. S. Pereira, D. Raes, and M. Smith (1998), Crop evapotranspiration: Guidelines for computing crop water requirements, FAO, Rome (Italy). Boesten, J., and L. Stroosnijder (1986), Simple model for daily evaporation from fallow tilled soil under spring conditions in a temperate climate, Neth. J. Agric. Sci., 34(1), 75-90.

Vanderborght, J.; Graf, A.; Steenpass, C.; Scharnagl, B.; Prolingheuer, N.; Herbst, M.; Vereecken, H.

2009-12-01

353

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

SciTech Connect

The performance of PAN-based composite absorbers was evaluated in dynamic experiments at flow rates ranging from 25--100 bed volumes (BV) per hour. Composite absorbers with active components of ammonium molybdophosphate (AMP) PAN and K-Co ferrocyanide (KCoFC) PAN were used for separating Cs from a 1 M HNO{sub 3} + 1 M NaNO{sub 3} + 2 {times} 10{sup {minus}5} M CsCl acidic simulant solution. KCoFC-PAN and two other FC-based composite absorbers were tested for separating Cs from alkaline simulant solutions containing 0.01 M to 1 M NaOH and 1 M NaNO{sub 3} + x {times} 10{sup {minus}4} M CsCl. The efficiency of the Cs sorption on the AMP-PAN absorber from acidic simulant solutions was negatively influenced by the dissolution of the AMP active component. At flow rates of 50 BV/hr, the decontamination factor of about 10{sup 3} could be maintained for treatment of 380 BV of the feed. With the KCoFC-PAN absorber, the decontamination factor of about 10{sup 3} could be maintained for a feed volume as great as 1,800 BV. In alkaline simulant solutions, significant decomposition of the active components was observed, and the best performance was exhibited by the KCoFC-PAN absorber. Introductory experiments confirmed that Cs may be washed out of the composite absorbers. Regeneration of both absorbers for repetitive use was also found to be possible. The main result of the study is that PAN was proven to be a versatile polymer capable of forming porous composite absorbers with a large number of primary absorbers. The composite absorbers proved to be capable of withstanding the harsh acidic and alkaline conditions and significant radiation doses that may be expected in the treatment of US DOE wastes. A field demonstration is proposed as a follow-on activity.

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

1996-05-01

354

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

355

Evaporator Development for an Evaporative Heat Pipe System  

NASA Technical Reports Server (NTRS)

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

Peters, Leigh C.

2004-01-01

356

Chemical evolution of multicomponent aerosol particles during evaporation  

NASA Astrophysics Data System (ADS)

Atmospheric aerosol particles have an important but not well quantified effect on climate and human health. Despite the efforts made in the last decades, the formation and evolution of aerosol particles in the atmosphere is still not fully understood. The uncertainty is partly due to the complex chemical composition of the particles which comprise inorganic and organic compounds. Many organics (like dicarboxylic acids) can be present both in the gas and in the condensed phase due to their low vapor pressure. Clearly, an understanding of this partition is crucial to address any other issue in atmospheric physics and chemistry. Moreover, many organics are water soluble, and their influence on the properties of aqueous solution droplets is still poorly characterized. The solid and sub-cooled liquid state vapor pressures of some organic compounds have been previously determined by measuring the evaporation rate of single-compound crystals [1-3] or binary aqueous droplets [4-6]. In this work, we deploy the HTDMA technique (Hygroscopicity Tandem Differential Mobility Analyzer) coupled with a 3.5m laminar flow-tube and an Aerosol Mass Spectrometer (AMS) for determining the chemical evolution during evaporation of ternary droplets made of one dicarboxylic acid (succinic acid, commonly found in atmospheric samples) and one inorganic compound (sodium chloride or ammonium sulfate) in different mixing ratios, in equilibrium with water vapor at a fixed relative humidity. In addition, we investigate the evaporation of multicomponent droplets and crystals made of three organic species (dicarboxylic acids and sugars), of which one or two are semi-volatile. 1. Bilde M. and Pandis, S.N.: Evaporation Rates and Vapor Pressures of Individual Aerosol Species Formed in the Atmospheric Oxidation of alpha- and beta-Pinene. Environmental Science and Technology, 35, 2001. 2. Bilde M., et al.: Even-Odd Alternation of Evaporation Rates and Vapor Pressures of C3-C9 Dicarboxylic Acid Aerosols, Environmental. Science and Technology, 37, 2003. 5. Koponen I.K., et al.: Thermodynamic properties of malonic, succinic, and glutaric acids: Evaporation rates and saturation vapor pressures. Environmental Science and Technology, 41, 2007. 4. Zardini A.A., et al.: White light Mie resonance spectroscopy used to measure very low vapor pressures of substances in aqueous solution aerosol particles. Optics Express, 14, 2006. 3. Zardini A.A. and Krieger, U.K.: Evaporation kinetics of a non-spherical, levitated aerosol particle using optical resonance spectroscopy for precision sizing. Optics Express, 17, 2009. 6. Riipinen, I., et al.: Adipic and Malonic Acid Aqueous Solutions: Surface Tensions and Saturation Vapor Pressures, J. Phys. Chem., 111, 2007.

Zardini, Alessandro; Riipinen, Ilona; Pagels, Joakim; Eriksson, Axel; Worsnop, Douglas; Switieckli, Erik; Kulmala, Markku; Bilde, Merete

2010-05-01

357

Evaporation of sessile droplets affected by graphite nanoparticles and binary base fluids.  

PubMed

The effects of ethanol component and nanoparticle concentration on evaporation dynamics of graphite-water nanofluid droplets have been studied experimentally. The results show that the formed deposition patterns vary greatly with an increase in ethanol concentration from 0 to 50 vol %. Nanoparticles have been observed to be carried to the droplet surface and form a large piece of aggregate. The volume evaporation rate on average increases as the ethanol concentration increases from 0 to 50 vol % in the binary mixture nanofluid droplets. The evaporation rate at the initial stage is more rapid than that at the late stage to dry, revealing a deviation from a linear fitting line, standing for a constant evaporation rate. The deviation is more intense with a higher ethanol concentration. The ethanol-induced smaller liquid-vapor surface tension leads to higher wettability of the nanofluid droplets. The graphite nanoparticles in ethanol-water droplets reinforce the pinning effect in the drying process, and the droplets with more ethanol demonstrate the depinning behavior only at the late stage. The addition of graphite nanoparticles in water enhances a droplet baseline spreading at the beginning of evaporation, a pinning effect during evaporation, and the evaporation rate. However, with a relatively high nanoparticle concentration, the enhancement is attenuated. PMID:25372453

Zhong, Xin; Duan, Fei

2014-11-26

358

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

NASA Astrophysics Data System (ADS)

Evaporation of forsterite, which plays an important role in chemical and isotope fractionation in the early solar nebula, is governed by surface kinetics strongly affected by surface conditions, such as surface roughness as well as density and orientation of dislocation outcrops. We have revealed anisotropies in evaporation rate and surface microstructure of forsterite and Fe-Mg olivine [1-3]. In order to better understand the kinetics of evaporation of forsteriete and olivine, we carried out experiments in a wider range of temperature and examined evaporation mode on the basis of temperature dependence of evaporation rates and surface microstructures. Experiments were carried out in a vacuum chamber internally heated by W mesh heater. Starting materials are single crystals of synthetic forsterite and natural Fe-Mg olivine (Fo~90), which are cut into crystallographically oriented rectangular parallelepipeds. The experimental temperature in the present and our previous studies ranged from 1300 to 1600 °C for Fe-Mg olivine and from 1500 to 1800 °C for forsterite. Surface microstructures of experimental residues were observed with SEM and EBSD, and face-specific evaporation rates were calculated from sample sizes and weight losses on at least three parallelepipeds with different [001]:[010]:[001] ratios. Development of Fe-Mg zoning due to preferential evaporation of Fe and Fe-Mg lattice diffusion in the sample was taken into consideration in rate estimation for olivine evaporation. The experimental results for both forsterite and olivine experiments demonstrated systematic temperature dependence of anisotropy in evaporation rate: (010)>(001)>(010) above ~1750°C, (001)>(100)>(010) at temperatures between ~1750 and ~1500°C, and (001)>(010)>(100) below ~1500°C. The maximum anistoropy in the evaporation rate is factor of 5 below ~1750°C, but the anisotropy is significantly suppressed above ~1750°C, where the differences among three evaporation rates are within 70% at ~1800°C. These crossovers in evaporation rate were intimately associated with changes in surface microstructures not directly related to surface morphologies originated from dislocation outcrops. Facets of (010) disappear on the (010) surface above ~1750°C, and (100) facets appear on the (100) surface below ~1500°C, which is consistently observed both for forsterite and olivine. The facets observed in SEM were confirmed to be atomistically flat consisting of stacking of layers with one or few unit-cells height through STM observations. On the contrary, non-facetted surfaces were confirmed to be atomistically rough. Therefore, the rate crossovers are attributed to rough-smooth transitions [4-5] at ~1500°C for (100) and at ~1750°C for (010). Such rough-smooth transition for the (001) surface is expected to exist below ~1500°C. The anisotropy in the rough-smooth transition temperature identified for forsterite and olivine cannot be explained solely by the differences in slice energy or attachment energy (anisotropy in bond stength) for the three crystallographic faces [6], which predicts that the transition temperture decreases in the order of (010), (001), and (100). The presence of Fe notably enhances stoichiometric evaporation of Fe-Mg olivine at 1500°C without forming any reaction product [3]. This suggests that stoichiometric evaporation from olivine or congruent evaporation from forsterite is controlled by removal of Mg2+ and Fe2+ from either the M1 or M2 site followed by spontaneous destruction of SiO4 tetrahedron at least above 1500°C, which is required not to result in incongruent evaporation forming enstatite layer. On the contrary, Fe-Mg olivine evaporates nonstoichiometrically to form enstatite at the forsterite surface at ~1300°C (Ozawa and Nagahara, 2002), where removal of Fe2+ or Mg2+ is not the rate-controlling process but Si removal or breaking Si-O bonds governs the overall reaction. The slow removal of Si results in nonstoichiometric evaporation via reaction with olivine residue to produce enstatite on the sur

Ozawa, K.; Nagahara, H.

2009-04-01

359

Evaporation from Lake Mead, Nevada and Arizona, March 2010 through February 2012  

USGS Publications Warehouse

Evaporation from Lake Mead was measured using the eddy-covariance method for the 2-year period starting March 2010 and ending February 2012. When corrected for energy imbalances, annual eddy-covariance evaporation was 2,074 and 1,881 millimeters (81.65 and 74.07 inches), within the range of previous estimates. There was a 9-percent decrease in the evaporation rate and a 10-percent increase in the lake surface area during the second year of the study compared to the first. These offsetting factors resulted in a nearly identical 720 million cubic meters (584,000 acre feet) evaporation volume for both years. Monthly evaporation rates were best correlated with wind speed, vapor pressure difference, and atmospheric stability. Differences between individual monthly evaporation and mean monthly evaporation were as much as 20 percent. Net radiation provided most of the energy available for evaporative processes; however, advected heat from the Colorado River was an important energy source during the second year of the study. Peak evaporation lagged peak net radiation by 2 months because a larger proportion of the net radiation that reaches the lake goes to heating up the water column during the spring and summer months. As most of this stored energy is released, higher evaporation rates are sustained during fall months even though net radiation declines. The release of stored heat also fueled nighttime evaporation, which accounted for 37 percent of total evaporation. The annual energy-balance ratio was 0.90 on average and varied only 0.01 between the 2 years, thus implying that 90 percent of estimated available energy was accounted for by turbulent energy measured using the eddy-covariance method. More than 90 percent of the turbulent-flux source area represented the open-water surface, and 94 percent of 30-minute turbulent-flux measurements originated from wind directions where the fetch ranged from 2,000 to 16,000 meters. Evaporation uncertainties were estimated to be 5 to 7 percent. A secondary evaporation method, the Bowen ratio energy budget method, also was employed to measure evaporation from Lake Mead primarily as a validation of eddy-covariance evaporation measurements at annual timescales. There was good agreement between annual corrected eddy-covariance and Bowen ratio energy budget evaporation estimates, providing strong validation of these two largely independent methods. Annual Bowen ratio energy budget evaporation was 6 and 8 percent greater than eddy-covariance evaporation for the 2 study years, and both methods indicated there was a similar decrease in evaporation from the first to the second year. Both methods produced negative sensible heat fluxes during the same months, and there was a strong correlation between monthly Bowen ratios (R2 = 0.94). The correlation between monthly evaporation (R2 = 0.65), however, was not as strong. Monthly differences in evaporation were attributed primarily to heat storage estimate uncertainty.

Moreo, Michael T.; Swancar, Amy

2013-01-01

360

Kinetics of diffusion-controlled evaporation of Fe-Mg olivine: experimental study and implication for stability of Fe-rich olivine in the solar nebula  

Microsoft Academic Search

Evaporation is a process that caused chemical fractionation in the solar nebula. The evaporation rates of meteorite-forming minerals and silicate melts are key parameters for constraining the timescale of high temperature processes in the early solar nebula and for understanding the mechanisms of cosmochemical fractionation. The kinetics of evaporation of olivine (initial Fo = 92), the most common silicate in

Kazuhito Ozawa; Hiroko Nagahara

2000-01-01

361

Testing of the Multi-Fluid Evaporator Engineering Development Unit  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

362

A microfluidic device based on an evaporation-driven micropump.  

PubMed

In this paper we introduce a microfluidic device ultimately to be applied as a wearable sweat sensor. We show proof-of-principle of the microfluidic functions of the device, namely fluid collection and continuous fluid flow pumping. A filter-paper based layer, that eventually will form the interface between the device and the skin, is used to collect the fluid (e.g., sweat) and enter this into the microfluidic device. A controllable evaporation driven pump is used to drive a continuous fluid flow through a microfluidic channel and over a sensing area. The key element of the pump is a micro-porous membrane mounted at the channel outlet, such that a pore array with a regular hexagonal arrangement is realized through which the fluid evaporates, which drives the flow within the channel. The system is completely fabricated on flexible polyethylene terephthalate (PET) foils, which can be the backbone material for flexible electronics applications, such that it is compatible with volume production approaches like Roll-to-Roll technology. The evaporation rate can be controlled by varying the outlet geometry and the temperature. The generated flows are analyzed experimentally using Particle Tracking Velocimetry (PTV). Typical results show that with 1 to 61 pores (diameter?=?250 ?m, pitch?=?500 ?m) flow rates of 7.3?×?10(-3) to 1.2?×?10(-1) ?L/min are achieved. When the surface temperature is increased by 9.4°C, the flow rate is increased by 130 %. The results are theoretically analyzed using an evaporation model that includes an evaporation correction factor. The theoretical and experimental results are in good agreement. PMID:25804609

Nie, Chuan; Frijns, Arjan J H; Mandamparambil, Rajesh; den Toonder, Jaap M J

2015-04-01

363

A simple technique for modulating the output of a cw e-beam evaporator  

NASA Astrophysics Data System (ADS)

Modulation of evaporation rate is desirable as it significantly increases the signal detection capability by making it possible to use phase sensitive techniques. An easy method for achieving modulation of evaporation rate via control of focus coil current is described. This method avoids the expense as well as complexities involved in doing the same by switching the e-gun acceleration voltage (>10 kV) or switching the grid bias on the e-gun (>2 kV).

Bhatia, M. S.; Joshi, A.; Patel, K.; Chatterjee, U. K.

1989-03-01

364

Putting the "vap" into evaporation  

NASA Astrophysics Data System (ADS)

In the spirit of the Special Issue of HESS to which it contributes, this paper documents the origin and development of the science of natural evaporation from land surfaces over the last 30-35 years, since the symposium A View from the Watershed was held to commemorate the opening of the new Institute of Hydrology (IH) building in 1973. Important subsequent technical progress includes the ability to measure routinely the diurnal cycle of near-surface meteorological variables using automatic weather stations, and of surface energy and momentum exchanges using automated implementations of the Bowen Ratio/Energy Budget technique and the Eddy Correlation technique, along with the capability to estimate the "fetch" for which these measurements apply. These improvements have been complemented by new methods to measure the separate components of evaporation, including: the interception process using randomly relocated below-canopy gauges, transpiration fluxes from individual leaves/shoots using porometers and from plants/plant components using stem-flow gauges and soil evaporation using micro-lysimeters and soil moisture depletion methods. In recent years progress has been made in making theory-based area-average estimates of evaporation using scintillometers, and model-based area-average estimates by assembling many streams of relevant data into Land Data Assimilation Systems. Theoretical progress has been made in extending near-surface turbulence theory to accommodate the effect of the "excess" boundary layer resistance to leaf-to-air transfer of energy and mass fluxes relative to that for momentum, and to allow for observed shortcoming in stability factors in the transition layer immediately above vegetation. Controversy regarding the relative merits of multi-layer model and "big leaf" representations of whole-canopy exchanges has been resolved in favour of the latter approach. Important gaps in the theory of canopy-atmosphere interactions have been filled, including recognising the need, separately, to represent dry-canopy and wet-canopy evaporation in models and the capability to describe wet-to-dry canopy transitions as well as the ability to describe sparse vegetation canopies which only partly cover the underlying soil. There is progress in methods of estimating crop water requirements, but an important recommendation of this paper is that this progress should continue by introducing use of an effective stomatal resistance rather than crop factors. The paper draws attention to relevant theoretical insight on this issue. Progress in theoretical understanding of evaporation processes has been used in the creation of numerous Land Surface Parameterisations (LSPs), the models used to represent land-surface interaction in climate and weather forecast models, and there have been important advances in describing the behaviour of plant stomata in LSPs. A major investment over the last 25 years in conducting Large-Scale Field Experiments, the better to measure, understand and model coupled land-surface/atmosphere interactions, has resulted in improvements in the capabilities of global climate models and the ability of mesoscale meteorological models to describe the enhanced circulation resulting from different forms of land-surface heterogeneity. Progress in understanding why early equations for potential evapotranspiration can be adequate in certain conditions is reviewed. The paper concludes with recommendations for future research.

Shuttleworth, W. J.

2007-01-01

365

Towards a Pan-European property index : methodological opportunities  

E-print Network

This study examines the methodological opportunities of index construction for the Pan-European property index, whose release is planned by the company Investment Property Databank (IPD). To address the question of temporal ...

Helfer, Friederike, 1976-

2004-01-01

366

STEREO Sees Comet Pan-STARRS - Duration: 0:33.  

NASA Video Gallery

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

367

Afro-Americans and Early Pan-Africanism  

ERIC Educational Resources Information Center

History of the Pan-African movement, the roles of W.E.B.Du Bois and Marcus Garvey in the movement activities, and the shift to African based leadership of the movement in the 1940's are discussed. (KG)

Contee, Clarence G.

1970-01-01

368

Photodegradation studies of silver-backed polyacrylonitrile (PAN) films  

SciTech Connect

Fourier transform infrared (FT-IR) reflection-absorbance (RA) measurements have been used to characterize Ag-backed polyacrylonitrile (PAN) films and to study their photodegradation. The optical constants n and k for the polymers are determined in the mid-IR region, and the dependence of RA values on polymer functionality concentration as a function of film thickness calculated. The IR-RA values are nearly linear with the concentration of functionalities for PAN films of thicknesses up to 0.1 ..mu..m. Some oxidative photodegradation pathways have been proposed; with radiation of lambda greater than or equal to 250 nm, a polyimine structure is generated. A combination of 1.0% wt of Irganox 1010 and 0.5% wt of Irgastab 2002 in PAN films was found to significantly retard the photodegradation of the polymer without affecting the specularity of the PAN/Ag surface.

Smith, D.M.; Chugtai, A.R.; Sergides, C.A.; Schissel, P.

1985-07-01

369

Electrical conductivity of doped polyacrylonitrile (PAN). [Halogen doped polyacrylonitrile  

SciTech Connect

The electrical conductivity and optical absorption spectra of halogen doped PAN have been investigated. When films of PAN previously heated in vacuum to 280/sup 0/C are exposed to bromine or iodine vapor the conductivity rises suddenly. The conductivity is reduced by pumping off the vapor, but upon subsequent reheating the conductivity increases dramatically, with a transition occurring at about 270/sup 0/C. Undoped samples were previously reported to undergo a similar transition above 390/sup 0/C. All samples obey sigma ..cap alpha.. T/sup -1/4/ behavior, suggesting 3-dimensional variable range hopping as the conduction mechanism. The optical and infrared absorption spectra of doped PAN are compared to those previously reported for the undoped material. The stability of doped PAN in air is also discussed. 7 figures.

Teoh, H.; MacInnes, D.; Metz, P.D.

1982-01-01

370

Pan-STARRS PS1 Observatory, Telescope and Instrument Control  

NASA Astrophysics Data System (ADS)

An ultimate goal for the final Pan-STARRS array (PS4) is fully robotic facility operations. To facilitate that development, PS1 is a remotely operable observatory that includes many features of the future robotic Pan-STARRS. Both remote and robotic operational concepts require sufficient knowledge of environmental conditions to support survey scheduling, and this requires an auxiliary instrumentation suite to measure meteorological and atmospheric conditions in addition to the control systems for the observatory and telescope. For the Pan-STARRS PS1 prototype, the monitoring, control, and summit subsystem coordination are handled by the HW/SW within the Observatory, Telescope, and Instrumentation Subsystem (OTIS). In this talk, we present the functional capabilities of OTIS, and the HW and SW architectures designed to meet the subsystem operational requirements. OTIS performance through early commissioning is described as well as the future plans to incorporate the Pan-STARRS scheduler into system operations.

Pier, E.; Chambers, K.

371

Out-of-tank evaporator demonstration. Final report  

SciTech Connect

The project reported here was conducted to demonstrate a skid-mounted, subatmospheric evaporator to concentrate liquid low-level waste (LLLW) stored in underground tanks at Oak Ridge National Laboratory (ORNL). This waste is similar to wastes stored at Hanford and Savannah River. A single-stage subatmospheric evaporator rated to produce 90 gallons of distillate per hour was procured from Delta Thermal, Inc., of Pensacola, Florida, and installed in an existing building. During the 8-day demonstration, 22,000 gal of LLLW was concentrated by 25% with the evaporator system. Decontamination factors achieved averaged 5 x 10{sup 6} (i.e., the distillate contained five million times less Cesium 137 than the feed). Evaporator performance substantially exceeded design requirements and expectations based on bench-scale surrogate test data. Out-of tank evaporator demonstration operations successfully addressed the feasibility of hands-on maintenance. Demonstration activities indicate that: (1) skid-mounted, mobile equipment is a viable alternative for the treatment of ORNL LLLW, and (2) hands-on maintenance and decontamination for movement to another site is achievable. Cost analysis show that 10% of the demonstration costs will be immediately recovered by elimination of solidification and disposal costs. The entire cost of the demonstration can be recovered by processing the inventory of Melton Valley Storage Tank waste and/or sluice water prior to solidifications. An additional savings of approximately $200,000 per year can be obtained by processing newly generated waste through the system. The results indicate that this type of evaporator system should be considered for application across the DOE complex. 25 refs., 11 figs., 2 tabs.

Lucero, A.J.; Jennings, H.L.; VanEssen, D.C. [and others

1998-02-01

372

Multipartite model of evaporative cooling in optical dipole traps  

NASA Astrophysics Data System (ADS)

We propose and study a model of forced evaporation of atomic clouds in crossed-beam optical dipole traps that explicitly includes the growth of a population in the "wings" of the trap and its subsequent impact on dimple temperature and density. It has long been surmised that a large wing population is an impediment to the efficient production of Bose-Einstein condensates in crossed-beam traps. Understanding the effect of the wings is particularly important for ? =1.06 ? m traps, for which a large ratio of Rayleigh range to beam waist results in wings that are large in volume and extend far from the dimple. Key ingredients to our model's realism are (1) our explicit treatment of the nonthermal, time-dependent energy distribution of wing atoms in the full anharmonic potential and (2) our accurate estimations of transition rates among dimple, wing, and free-atom populations, obtained with Monte Carlo simulations of atomic trajectories. We apply our model to trap configurations in which neither, one, or both of the wing potentials are made unbound by applying a "tipping" gradient. We find that forced evaporation in a trap with two bound wing potentials produces a large wing population which can collisionally heat the dimple so strongly as to preclude reaching quantum degeneracy. Evaporation in a trap with one unbound wing, such as that made by crossing one vertical beam and one horizontal beam, also leads to a persistent wing population which dramatically degrades the evaporation process. However, a trap with both wings tilted so as to be just unbound enjoys a nearly complete recovery of efficient evaporation. By introducing to our physical model an ad hoc, tunable escape channel for wing atoms, we study the effect of partially filled wings, finding that a wing population caused by single-beam potentials can drastically slow down evaporative cooling and increase the sensitivity to the choice of ? .

Williams, Matthew J.; Fertig, Chad

2015-02-01

373

Predicting Capacity Demand on Sanctuaries for African Chimpanzees ( Pan troglodytes )  

Microsoft Academic Search

Wildlife sanctuaries rescue, rehabilitate, reintroduce, and provide life-long care for orphaned and injured animals. Understanding\\u000a a sanctuary’s patterns in arrival, mortality, and projected changes in population size can help managers plan carefully for\\u000a future needs, as well as illuminate patterns in source populations of wildlife. We studied these dynamics for chimpanzees\\u000a (Pan troglodytes) in 11 sanctuaries of the Pan African

Lisa J. Faust; Doug Cress; Kay H. Farmer; Stephen R. Ross; Benjamin B. Beck

374

Temporary Interconnection of ZigBee Personal Area Network (PAN)  

Microsoft Academic Search

ZigBee is popular for Wireless Sensor Network (WSN) devices because of its low power consumption, built-in security method and ratified specifications. With these features, it is also suitable to be used with medical sensor devices. Medical sensors in a human body self organize a ZigBee Personal Area Network (PAN). These PANs are interconnected and form a HealthNet. For the interconnection,

Sewook Jung; Alexander Chang; Mario Gerla

2007-01-01

375

Pan-European branding: CPC International and Knorr  

Microsoft Academic Search

European food manufacturers are switching to pan-European marketing and rationalizing manufacturing operations to achieve economies of scale as margins are squeezed by retailers and brand loyalty wanes. The US multinational CPC International appears to epitomize this trend. However, its focus on manufacturing efficiencies cannot compensate for long-standing marketing inefficiencies. It needs to recognize that although it has a pan-European approach

Michael C. McDermott

1997-01-01

376

Relationships between PAN and ozone at sites in eastern  

Microsoft Academic Search

Measurements of ozone and PAN (peroxyacetic nitric anhydride) were made at four sites in eastern North America; Bondville, Illinois, Egbert, Ontario, Scotia, Pennsylvania, and Whitetop Mountain, Virginia., in July and August of 1988 as part of a study of regional oxidant photochemistry. The concentrations of PAN ranged from <0.010 to 9.2 parts-per-billion by volume (ppbv) and those of 03 ranged

J. M. Roberts; R. L. Tanner; L. Newman; V. C. Bowersox; J. W. Bottenheim; K. G. Anlauf; K. A. Brice; D. D. Parrish; F. C. Fehsenfeld; M. P. Buhr; J. F. Meagher; E. M. Bailey

1995-01-01

377

Pan-cancer patterns of somatic copy-number alteration  

PubMed Central

Determining how somatic copy-number alterations (SCNAs) promote cancer is an important goal. We characterized SCNA patterns among 4934 cancers from The Cancer Genome Atlas Pan-Cancer dataset. Whole-genome doubling, observed in 37% of cancers, was associated with higher rates of every other type of SCNA, TP53 mutations, CCNE1 amplifications, and alterations of the PPP2R complex. SCNAs that were internal to chromosomes tended to be shorter than telomere-bounded SCNAs, suggesting different mechanisms of generation. Significantly recurrent focal SCNAs were observed in 140 regions, including 102 without known oncogene or tumor suppressor gene targets and 50 with significantly mutated genes. Amplified regions without known oncogenes are enriched for genes involved in epigenetic regulation. When levels of genomic disruption were accounted for, 7% of region pairs anticorrelated, and these tended to encompass genes whose proteins physically interact, suggesting related functions. These results provide insights into mechanisms of generation and functional consequences of cancer SCNAs. PMID:24071852

Zack, Travis I.; Schumacher, Steven E.; Carter, Scott L.; Cherniack, Andrew D.; Saksena, Gordon; Tabak, Barbara; Lawrence, Michael S.; Zhang, Cheng-Zhong; Wala, Jeremiah; Mermel, Craig H.; Sougnez, Carrie; Gabriel, Stacey B.; Hernandez, Bryan; Shen, Hui; Laird, Peter W.; Getz, Gad; Meyerson, Matthew; Beroukhim, Rameen

2013-01-01

378

A pan-African Flood Forecasting System  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

379

The Pan-STARRS Project in 2014  

NASA Astrophysics Data System (ADS)

The Pan-STARRS telescopes are a distributed aperture approach to rapid, multi-color wide-field surveys. The first of these telescopes, a prototype designated PS1, has been in operation now for over three years and has already obtained complete sky coverage of the full 3-? steradians visible from Haleakala in 5 broad passband filters at multiple epochs. On average the PS1 survey has obtained approximately 12 epochs though each filter. The second telescope, designated PS2, has been in its commissioning phase since August 2013 and will begin science operations in the second half of 2014. Several design and fabrication changes in both the telescope and the camera have been implemented in PS2. This talk will describe the science results that have been coming out of the PS1 survey, the design changes implemented on PS2, and the current performance of the PS2 telescope and camera. We will also describe the future missions for the PS1 and PS2 telescopes as of the current year.

Morgan, Jeffrey S.; Burgett, William; Onaka, Peter

2014-07-01

380

Origin and evolution of major salts in the Darling pans, Western Cape, South Africa  

Microsoft Academic Search

Sediment and water samples from 12 saline pans on the semi-arid west coast of South Africa were analysed to determine the origin of salts and geochemical evolution of water in the pans. Pans in the area can be subdivided into large, gypsiferous coastal pans with 79–150 g\\/kg total dissolved salt (TDS), small inland brackish to saline (2–64 g\\/kg TDS) pans

Meris Smith; John S. Compton

2004-01-01

381

Field evaporation mechanism of bulk oxides under ultra fast laser illumination  

NASA Astrophysics Data System (ADS)

The controlled field evaporation of single atoms from an oxide surface assisted by ultra fast laser pulses has recently been demonstrated. When UV light is used, a photoionization mechanism was proposed. However, experimental results observed when the laser intensity and wavelength are changed cannot be explained by this mechanism. Instead, a thermal assisted evaporation mechanism characterized by two evaporation times is proposed. The fast and slow evaporation rates are associated to two cooling processes inside the tip sample. Experiments are carried out on TiO2 and MgO field emitter tips to check the dependence of the evaporation process on structural properties of the oxide. A good agreement between the predictions of our model and the experimental data is found.

Vella, A.; Mazumder, B.; Da Costa, G.; Deconihout, B.

2011-08-01

382

The effect of evaporator operating parameters on the flow patterns inside horizontal pipes  

NASA Astrophysics Data System (ADS)

A general and simple model for simulating the steady state behaviors of air-to-refrigerant fin-and-tube evaporator is introduced with the focus on the detailed flow patterns inside the tubes. In order to simulate the heat transfer between air and the working fluid, the evaporator is divided into a number of control volumes. Empirical correlations from literature were also adopted to estimate the void fraction, the internal and external heat transfer coefficients, and the pressure drops. Simulations were performed to study the effects of varying inlet air temperature, refrigerant mass flow rate and evaporation pressure on the flow patterns inside the horizontal pipe of the evaporator. The simulation results indicate that the proposed model can be used to predict flow patterns well. The predicted results of the model agree well with experimental results, the difference is within ±3% for the cooling capacity, and is within ±0.2% for refrigerant evaporation temperature.

Tong, Lige; Li, Haiyan; Wang, Li; Sun, Xinxing; Xie, Yunfei

2011-08-01

383

Evaluating evaporation from field crops using airborne radiometry and ground-based meteorological data  

USGS Publications Warehouse

Airborne measurements of reflected solar and emitted thermal radiation were combined with ground-based measurements of incoming solar radiation, air temperature, windspeed, and vapor pressure to calculate instantaneous evaporation (LE) rates using a form of the Penman equation. Estimates of evaporation over cotton, wheat, and alfalfa fields were obtained on 5 days during a one-year period. A Bowen ratio apparatus, employed simultaneously, provided ground-based measurements of evaporation. Comparison of the airborne and ground techniques showed good agreement, with the greatest difference being about 12% for the instantaneous values. Estimates of daily (24 h) evaporation were made from the instantaneous data. On three of the five days, the difference between the two techniques was less than 8%, with the greatest difference being 25%. The results demonstrate that airborne remote sensing techniques can be used to obtain spatially distributed values of evaporation over agricultural fields. ?? 1987 Springer-Verlag.

Jackson, R. D.; Moran, M.S.; Gay, L.W.; Raymond, L.H.

1987-01-01

384

Observations on an evaporative, elbow thermosyphon  

SciTech Connect

The performance of the evaporative elbow system was found to be superior to that of the nonevaporative system, but comparable to the performance of the linear system. The parametric role of the evaporator wall temperature, the condenser wall temperature, and the vapor saturation temperature was demonstrated, each revealing a similar monotonic effect. With the evaporator upright, the data were found to be similar to, but displaced from, the upright condenser data. The upright evaporator gave the better performance, but not overwhelmingly so. The limit of performance with the condenser upright was found to be dictated by evaporator dryout. In the upright evaporator configuration, the limit may be attributed to flooding in the poorly draining condenser; this limit was indistinguishable from geyser behavior at low vapor pressures. 16 refs., 3 figs.

Lock, G.S.H.; Fu, J. (Univ. of Alberta, Edmonton (Canada))

1993-05-01

385

Effect of polyacrylonitrile (PAN) short fiber on the mechanical properties of PAN\\/EPDM thermal insulating composites  

Microsoft Academic Search

Polyacrylonitrile short fibers\\/ethylene–propylene–diene terpolymer rubber (PAN\\/EPDM) composites are prepared for the first time by mechanical mixing and subsequent vulcanization at 150°C for 50min to substitute for composites reinforced with aramid short fibers, as thermal insulating materials. The relationships between fiber content and the mechanical performances of the two kinds of composites are investigated. To PAN\\/EPDM composites and aramid\\/EPDM composites, as

Shan Jin; Yuansuo Zheng; Guoxin Gao; Zhihao Jin

2008-01-01

386

Experimental search for evaporating primordial black holes  

NASA Astrophysics Data System (ADS)

Primordial black holes (PBHs) are black holes which may form in the early Universe through the gravitational collapse of primordial cosmological density fluctuations. Due to Hawking radiation these PBHs are supposed to evaporate by emitting particles. Recent developments in the experimental searching for evaporating PBHs in the local Universe are reviewed. The technique of searching for the gamma-ray bursts (GRBs) from evaporating PBHs on shower arrays is discussed.

Petkov, V. B.

2015-03-01

387

Spatially Resolved Evaporative Patterns from Water  

E-print Network

Unexpectedly distinct patterns in evaporation were observed over heated water. Although the patterns had chaotic aspects, they often showed geometric patterns. These patterns bore strong resemblance to the infrared emission patterns observable with a mid-infrared camera focused on the water surface. This similarity puts constraints on the mechanism of evaporation, and leads to a general hypothesis as to the nature of the evaporative process.

Ienna, Federico; Pollack, Gerald H

2011-01-01

388

Water Purification by Evaporation and Condensation  

NSDL National Science Digital Library

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

389

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

PubMed Central

The two species of Pan, bonobos and common chimpanzees, have been reported to have different social organization, cognitive and linguistic abilities and motor skill, despite their close biological relationship. Here, we examined whether bonobos and chimpanzee differ in selected brain regions that may map to these different social and cognitive abilities. Eight chimpanzees and eight bonobos matched on age, sex and rearing experiences were magnetic resonance images scanned and volumetric measures were obtained for the whole brain, cerebellum, striatum, motor-hand area, hippocampus, inferior frontal gyrus and planum temporale. Chimpanzees had significantly larger cerebellum and borderline significantly larger hippocampus and putamen, after adjusting for brain size, compared with bonobos. Bonobos showed greater leftward asymmetries in the striatum and motor-hand area compared with chimpanzees. No significant differences in either the volume or lateralization for the so-called language homologs were found between species. The results suggest that the two species of Pan are quite similar neurologically, though some volumetric and lateralized differences may reflect inherent differences in social organization, cognition and motor skills. PMID:19760676

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

2009-01-01

390

Evaluation of a locally homogeneous model of spray evaporation  

NASA Technical Reports Server (NTRS)

A model of spray evaporation which employs a second-order turbulence model in conjunction with the locally homogeneous flow approximation, which implies infinitely fast interphase transport rates is presented. Measurements to test the model were completed for single phase constant and variable density jets, as well as an evaporating spray in stagnant air. Profiles of mean velocity, composition, temperature and drop size distribution as well as velocity fluctuations and Reynolds stress, were measured within the spray. Predictions were in agreement with measurements in single phase flows and also with many characteristics of the spray, e.g. flow width, radial profiles of mean and turbulent quantities, and the axial rate of decay of mean velocity and mixture fraction.

Shearer, A. J.; Faeth, G. M.

1979-01-01

391

Portable brine evaporator unit, process, and system  

DOEpatents

The present invention discloses a comprehensive, efficient, and cost effective portable evaporator unit, method, and system for the treatment of brine. The evaporator unit, method, and system require a pretreatment process that removes heavy metals, crude oil, and other contaminates in preparation for the evaporator unit. The pretreatment and the evaporator unit, method, and system process metals and brine at the site where they are generated (the well site). Thus, saving significant money to producers who can avoid present and future increases in transportation costs.

Hart, Paul John (Indiana, PA); Miller, Bruce G. (State College, PA); Wincek, Ronald T. (State College, PA); Decker, Glenn E. (Bellefonte, PA); Johnson, David K. (Port Matilda, PA)

2009-04-07

392

Apparatus and method for evaporator defrosting  

DOEpatents

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

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

2001-01-01

393

Variability of Pan-based and Penman-based Evapotranspiration Estimates in California  

NASA Astrophysics Data System (ADS)

Daily data from 29 meteorological stations from the California Irrigation Management Information System (CIMIS) covering the period from 1990 to 2002, and from 7 pan-evaporation stations from the National Climatic Data Center (NCDC), were used to characterize variability and trends in reference evapotranspiration (ETo) in California. ETo daily anomalies in California exhibited higher variance during the spring compared to other seasons. The higher variance is associated with larger ETo seasonal values -due to the higher spring irradiance- compared to winter and autumn, combined with large ETo reductions associated with relatively common cloudy days. Although the irradiance is also high during the summer, ETo estimates during this season are very close to the seasonal -clear sky- medians and therefore have low variance, due to the much lower frequency of occurrence of cloudy days. The combination of high seasonal values and relatively frequent cloudy days is only observed during the spring, the most variable season in terms of ETo. Atmospheric circulations at 700 mbar pressure levels (Z700) over a region off the West Coast of North America, approximately between 30 and 45 latitude, are most closely associated with the historical ETo variations. ETo is significantly positively correlated (r=+0.7) with Z700 in this region at daily, monthly and seasonal time scales, especially during the spring, through atmospheric circulation influences on the variability of radiation, relative humidity and cloudiness. This correlation pattern was identified using the CIMIS data (1990 to 2002) and its robustness was verified using the pan data (1965 to 2000). This pattern is consistent with other studies that have showed connections between atmospheric circulation in the eastern Pacific and precipitation and streamflow variations in California. Estimates of spring actual evapotranspiration from 1984 to 2002 computed based on the CIMIS data showed moderate, but significant increasing trends in most of the Central Valley, generally associated with increasing trends in minimum temperature. Future work will verify these trends using the NCDC data.

Hidalgo, H. G.; Dettinger, M. D.; Cayan, D. R.

2003-12-01

394

Pan-STARRS - A New Generation Survey Telescope System  

NASA Astrophysics Data System (ADS)

The University of Hawaii Institute for Astronomy is developing a large optical synoptic survey telescope system: the Panoramic Survey Telescope and Rapid Response System. When completed, Pan-STARRS will consist of an array of four 1.8m optical subsystems with a very large field of view (7 square degrees). Each optical system will be equipped with a 1.4 billion pixel CCD camera possessing low noise and rapid readout features. The collected image data will be reduced in near real time to produce both cumulative static sky and difference images from which stationary transients or variables and moving objects can be detected. Pan-STARRS will be capable of surveying up to ?6000 square degrees per night to a detection limit of approximately 24th magnitude. A major goal of the project is to survey for potentially hazardous objects (PHOs) with Pan-STARRS capable of detecting and establishing orbits for most objects down to 300m size, a 3x improvement over the current best asteroid search programs. In addition, Pan-STARRS data will be used to address a wide range of astronomical questions in the Solar System, the Galaxy, and the Cosmos at large. This talk is intended to outline the Pan-STARRS science goals, the top-level science requirements, and the various survey modes needed to support these goals. A detailed comparison is made between the performance metric for Pan-STARRS and the future LSST design. We show simulated projected completeness for detection of PHOs of various impact energies, and indicate the capability of Pan-STARSR to conduct dark energy science in anticipation of future programs such as LSST or JEDI.

Kaiser, N.

395

The third climate state: Proterozoic pan-glacial events  

NASA Astrophysics Data System (ADS)

In Climate Through the Ages (1926), C.E.P. Brooks distinguished two discrete climate states in the Phanerozoic, non-glacial (no continental ice sheets) and glacial-interglacial (1-4 continental ice sheets). It now appears that pan-glacial climate states (ice sheets on all continents) existed near the beginning and end of the Proterozoic eon, around 0.64, 0.71 and 2.22 Ga. Their existence is inferred from (1) integrated paleomagnetic and sedimentologic evidence for tidewater glaciers at paleolatitudes <20°, (2) submarine ice grounding-line wedges within carbonate-dominated successions, (3) synglacial banded iron-formations, and (4) distinctive syndeglacial cap carbonates. Pan-glacial models envision tropical oceans either ice-covered (snowball) or ice-free (slushball). The latter are biologically more benign but do not explain the iron-formations or cap carbonates. Glacioeustatic changes of ~1.5 km provide fresh support for the 0.64-Ga pan-glacial event and new evidence for high pCO2 from boron, calcium, carbon and sulfate triple-oxygen isotopes in cap carbonates favors the snowball option. Microfossils and biomarkers suggest that the advent of multicellular animal life was nearly coincident with the same pan-glacial event. Some view this as favoring the slushball option, while others infer that the environmental stress of a snowball drove the biological revolution. Future research directions include causation in light of pronounced negative ?13C excursions that precede the two younger pan- glacial events, geochemical cycling in variably ice-covered low-pH oceans, apparent hyperfast geomagnetic field reversals during the last pan-glacial event, atmosphere-ocean dynamics attending deglaciation, depauperate planktonic microbiota between the younger pan-glacial events, and the 1.5-billion-year non- glacial interval following the 2.22-Ga event. The author thanks geologist-paleomagnetist Edward (Ted) Irving for bringing to his attention the book by Brooks.

Hoffman, P. F.

2008-12-01

396

Cooling towers and evaporative condensers.  

PubMed

By 31 October 1978 there had been four confirmed instances where the Legionnaires' disease bacterium had been isolated from water samples taken from cooling towers or evaporative condensers located near the site of an epidemic of Legionnaires' disease. These devices are widely used to reject unwanted heat into the atmosphere and vary greatly in size and configuration. However, the operation of all towers and condensers depends on intimate contact between the circulating water and ambient air. Airborne contaminants in the vicinity of these devices are likely to be absorbed to some degree by the circulating water. The airstream leaving a cooling tower is saturated with water vapor and may also contain a relatively minute portion of the circulating water in the form of fine droplets known as drift. It is common practice to bleed a small portion of the circulating water, including all contaminants, from the tower into a storm sewer, sanitary sewer, or even a nearby body of water. PMID:434654

Miller, R P

1979-04-01

397

Hollow Fiber Ground Evaporator Unit Testing  

NASA Technical Reports Server (NTRS)

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

Bue, Grant; Trevino, Luis; Tsioulos, Gus

2010-01-01

398

Century Scale Evaporation Trend: An Observational Study  

NASA Technical Reports Server (NTRS)

Several climate models with different complexity indicate that under increased CO2 forcing, runoff would increase faster than precipitation overland. However, observations over large U.S watersheds indicate otherwise. This inconsistency between models and observations suggests that there may be important feedbacks between climate and land surface unaccounted for in the present generation of models. We have analyzed century-scale observed annual runoff and precipitation time-series over several United States Geological Survey hydrological units covering large forested regions of the Eastern United States not affected by irrigation. Both time-series exhibit a positive long-term trend; however, in contrast to model results, these historic data records show that the rate of precipitation increases at roughly double the rate of runoff increase. We considered several hydrological processes to close the water budget and found that none of these processes acting alone could account for the total water excess generated by the observed difference between precipitation and runoff. We conclude that evaporation has increased over the period of observations and show that the increasing trend in precipitation minus runoff is correlated to observed increase in vegetation density based on the longest available global satellite record. The increase in vegetation density has important implications for climate; it slows but does not alleviate the projected warming associated with greenhouse gases emission.

Bounoui, Lahouari

2012-01-01

399

CHROMOSPHERIC EVAPORATION VIA ALFVEN WAVES  

SciTech Connect

This paper presents a scenario for the chromospheric evaporation during solar flares, which is inspired by the chain of events leading to the formation of auroral arcs and ionospheric evacuation during magnetospheric substorms. The plasma, ejected from high coronal altitudes during a flare reconnection event, accumulates at the tops of coronal loops by braking of the reconnection flow, possibly by fast shock formation. A high-beta layer forms and distorts the magnetic field. Energy contained in magnetic shear stresses is transported as Alfven waves from the loop-top toward the chromosphere. It is shown that under these conditions the Alfven waves carry enough energy to feed the chromospheric evaporation process. The second subject of this investigation is identification of the most effective energy dumping or wave dissipation process. Several processes are being analyzed: ion-neutral collisions, classical and anomalous field-aligned current dissipation, and critical velocity ionization. All of them are being discarded, either because they turn out to be insufficient or imply very unlikely physical properties of the wave modes. It is finally concluded that turbulent fragmentation of the Alfven waves entering the chromosphere can generate the required damping. The basic process would be phase mixing caused by a strongly inhomogeneous distribution of Alfvenic phase speed and laminar flow breakup by Kelvin-Helmholtz (K-H) instability. The filamentary (fibril) structure of the chromosphere thus appears to be essential for the energy conversion, in which the K-H instability is the first step in a chain of processes leading to ion thermalization, electron heating, and neutral particle ionization. Quantitative estimates suggest that a transverse structure with scales not far below 100 km suffices to produce strong wave damping within a few seconds. Nonthermal broadening of some metallic ion lines observed during the pre-impulsive rise phase of a flare might be a residue of the turbulent breakup process.

Haerendel, Gerhard, E-mail: hae@mpe.mpg.d [Max Planck Institute for Extraterrestrial Physics, P.O. Box 1312, 85741 Garching (Germany)

2009-12-20

400

The ATLAS PanDA Monitoring System and its Evolution  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

401

The Pan-STARRS1 Small Area Survey 2  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

402

Overview of ATLAS PanDA Workload Management  

SciTech Connect

The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in addition to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.

Maeno T.; De K.; Wenaus T.; Nilsson P.; Stewart G. A.; Walker R.; Stradling A.; Caballero J.; Potekhin M.; Smith D.

2011-01-01

403

Overview of ATLAS PanDA Workload Management  

NASA Astrophysics Data System (ADS)

The Production and Distributed Analysis System (PanDA) plays a key role in the ATLAS distributed computing infrastructure. All ATLAS Monte-Carlo simulation and data reprocessing jobs pass through the PanDA system. We will describe how PanDA manages job execution on the grid using dynamic resource estimation and data replication together with intelligent brokerage in order to meet the scaling and automation requirements of ATLAS distributed computing. PanDA is also the primary ATLAS system for processing user and group analysis jobs, bringing further requirements for quick, flexible adaptation to the rapidly evolving analysis use cases of the early datataking phase, in addition to the high reliability, robustness and usability needed to provide efficient and transparent utilization of the grid for analysis users. We will describe how PanDA meets ATLAS requirements, the evolution of the system in light of operational experience, how the system has performed during the first LHC data-taking phase and plans for the future.

Maeno, T.; De, K.; Wenaus, T.; Nilsson, P.; Stewart, G. A.; Walker, R.; Stradling, A.; Caballero, J.; Potekhin, M.; Smith, D.; ATLAS Collaboration

2011-12-01

404

The Potential of panHER Inhibition in Cancer  

PubMed Central

Purpose: Hyper-activation of the HER (erbB) family receptors, HER 1-4, leads to up-regulation of the three vital signaling pathways: mitogen activated protein kinase, phosphoinositide 3-kinase/AKT, and Janus kinase/signal transducer and activator of transcription pathways. Blocking HER1/EGFR has a limited anticancer effect due to either secondary mutation e.g., T790M or by-pass signaling of other HER members. The emergence of an anti-panHER approach to blockade of these pathways as a cancer treatment may provide a solution to this resistance. This review aimed to provide an overview of the HER signaling pathways and their involvement in tumor progression and examine the current progress in panHER inhibition. Methods: Recent literature associated with HER signaling pathways and panHER inhibition was reviewed through PubMed and Medline database, followed by critical comparison and analysis. Results: Pre-clinical studies and clinical trials of panHER inhibitors show promising results, and the potential to improve patient outcomes in solid cancers. Conclusion:?The use of panHER inhibitors in cancers with HER-family hyper-activation, such as other epithelial cancers and sarcoma, is a new direction to research and has potential in clinical cancer therapy in the future. PMID:25674538

Wang, Xiaochun; Batty, Kathleen M.; Crowe, Philip J.; Goldstein, David; Yang, Jia-Lin

2015-01-01

405

Analysis of organic solvents and liquid mixtures using a fiber-tip evaporation sensor  

NASA Astrophysics Data System (ADS)

The instantaneous size and rate of evaporation of pendant liquid droplets placed on the cleaved facet of a standard fiber are reconstructed based on reflected optical power. Using the evaporation dynamics, the relative contents of ethanol in ethanol-water binary mixtures are assessed with 1% precision and different blends of methanol in gasoline are properly recognized. The latter application, in particular, is significant for the use of alternative fuels in the automotive sector. Also, ten organic solvents are identified based on their evaporation from a fiber facet coated with a hydrophobic, selfassembled monolayer.

Preter, Eyal; Donlagic, Denis; Artel, Vlada; Katims, Rachel A.; Sukenik, Chaim N.; Zadok, Avi

2014-05-01

406

Twenty Years of Evaporative Light Scattering Detection  

Microsoft Academic Search

Evaporative light scattering detector (ELSD) is a quasi-universal detector for liquid, countercurrent and supercritical fluid chromatography, since it can detect any analyte less volatile than the mobile phase. Operation principle mainly consists of three successive processes: nebulization of the chromatographic effluent; evaporation of the mobile phase; measurement of the scattered light. After 20 years of development, its usage appears significant

Nikolaos C. Megoulas; Michael A. Koupparis

2005-01-01

407

Representational Issues in Students Learning about Evaporation  

ERIC Educational Resources Information Center

This study draws on recent research on the central role of representation in learning. While there has been considerable research on students' understanding of evaporation, the representational issues entailed in this understanding have not been investigated in depth. The study explored students' engagement with evaporation phenomena through…

Tytler, Russell; Prain, Vaughan; Peterson, Suzanne

2007-01-01

408

Advanced evaporator technology progress report FY 1992  

SciTech Connect

This report summarizes the work that was completed in FY 1992 on the program {open_quotes}Technology Development for Concentrating Process Streams.{close_quotes} The purpose of this program is to evaluate and develop evaporator technology for concentrating radioactive waste and product streams such as those generated by the TRUEX process. Concentrating these streams and minimizing the volume of waste generated can significantly reduce disposal costs; however, equipment to concentrate the streams and recycle the decontaminated condensates must be installed. LICON, Inc., is developing an evaporator that shows a great deal of potential for this application. In this report, concepts that need to be incorporated into the design of an evaporator operated in a radioactive environment are discussed. These concepts include criticality safety, remote operation and maintenance, and materials of construction. Both solubility and vapor-liquid equilibrium data are needed to design an effective process for concentrating process streams. Therefore, literature surveys were completed and are summarized in this report. A model that is being developed to predict vapor phase compositions is described. A laboratory-scale evaporator was purchased and installed to study the evaporation process and to collect additional data. This unit is described in detail. Two new LICON evaporators are being designed for installation at Argonne-East in FY 1993 to process low-level radioactive waste generated throughout the laboratory. They will also provide operating data from a full-sized evaporator processing radioactive solutions. Details on these evaporators are included in this report.

Chamberlain, D.; Hutter, J.C.; Leonard, R.A. [and others

1995-01-01

409

Water evaporation: a transition path sampling study.  

PubMed

We use transition path sampling to study evaporation in the SPC/E model of liquid water. On the basis of thousands of evaporation trajectories, we characterize the members of the transition state ensemble (TSE), which exhibit a liquid-vapor interface with predominantly negative mean curvature at the site of evaporation. We also find that after evaporation is complete, the distributions of translational and angular momenta of the evaporated water are Maxwellian with a temperature equal to that of the liquid. To characterize the evaporation trajectories in their entirety, we find that it suffices to project them onto just two coordinates: the distance of the evaporating molecule to the instantaneous liquid-vapor interface and the velocity of the water along the average interface normal. In this projected space, we find that the TSE is well-captured by a simple model of ballistic escape from a deep potential well, with no additional barrier to evaporation beyond the cohesive strength of the liquid. Equivalently, they are consistent with a near-unity probability for a water molecule impinging upon a liquid droplet to condense. These results agree with previous simulations and with some, but not all, recent experiments. PMID:23294322

Varilly, Patrick; Chandler, David

2013-02-01

410

Water Evaporation: A Transition Path Sampling Study  

E-print Network

We use transition path sampling to study evaporation in the SPC/E model of liquid water. Based on thousands of evaporation trajectories, we characterize the members of the transition state ensemble (TSE), which exhibit a liquid-vapor interface with predominantly negative mean curvature at the site of evaporation. We also find that after evaporation is complete, the distributions of translational and angular momenta of the evaporated water are Maxwellian with a temperature equal to that of the liquid. To characterize the evaporation trajectories in their entirety, we find that it suffices to project them onto just two coordinates: the distance of the evaporating molecule to the instantaneous liquid-vapor interface, and the velocity of the water along the average interface normal. In this projected space, we find that the TSE is well-captured by a simple model of ballistic escape from a deep potential well, with no additional barrier to evaporation beyond the cohesive strength of the liquid. Equivalently, they are consistent with a near-unity probability for a water molecule impinging upon a liquid droplet to condense. These results agree with previous simulations and with some, but not all, recent experiments.

Patrick Varilly; David Chandler

2012-12-12

411

Formation and evaporation of charged black holes  

Microsoft Academic Search

We investigate the dynamical formation and evaporation of a spherically symmetric charged black hole. We study the self-consistent one loop order semiclassical back reaction problem. To this end the mass evaporation is modeled by an expectation value of the stress-energy tensor of a neutral massless scalar field, while the charge is not radiated away. We observe the formation of an

Evgeny Sorkin; Tsvi Piran

2001-01-01

412

Evaporation of two-dimensional black holes  

Microsoft Academic Search

An interesting two-dimensional model theory has been proposed that allows one to consider black-hole evaporation in the semiclassical approximation. The semiclassical equations will give a singularity where the dilation field reaches a certain critical value. This singularity will be hidden behind a horizon. As the evaporation proceeds, the dilation field on the horizon will approach the critical value but the

S. W. Hawking

1992-01-01

413

August 15, 1997 Density of Evaporated Milk  

E-print Network

August 15, 1997 1 Density of Evaporated Milk Report prepared by: Panickos N. Palettas, Director milk, given the milk's Percent Butterfat and Percent Milk Solids (other than fat). The standard for evaporated milk is 6.5% Fat and 23.0% Total Milk Solids (including fat). To facilitate the development

Santner, Thomas

414

Evolution of Energy Transfer Process between Quantum Dots of Two Different Sizes during the Evaporation of Solvent  

NASA Astrophysics Data System (ADS)

CdSe quantum dots (QDs) of two different sizes were dispersed in toluene solvent. We observed that the photoluminescence (PL) intensity of smaller QDs was gradually depressed by larger QDs during the evaporation of solvent. This is attributed to fluorescence resonance energy transfer (FRET) between two different sized QDs, when the distance between QDs is enough small to ensure close proximity. From PL intensity ratio of smaller to larger QDs, three stages can be distinguished during the evaporation and FRET rate begin to increase in the gel like stage. We estimated the mean distance variation between smaller and larger QDs during the evaporation from PL measurement and Dexter theory. In the solid resulted from the evaporation, FRET rate from smaller to larger dots and FRET rate within smaller QDs were quantitatively estimated to be 0.13 and 0.08 ns-1, respectively. The change in PL properties due to the aggregation of QDs by evaporation is discussed.

Lü, Wei; Umezu, Ikurou; Sugimura, Akira

2008-08-01

415

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

416

Factors controlling the drop evaporation constant.  

PubMed

In this paper, we discuss the factors affecting drop evaporation. We found that the droplet morphology at a specific temperature was controlled by the physical properties of the liquid itself, such as the molecular weight, density, diffusion coefficient in air, and heat of vaporization. Two processes are included in drop evaporation: diffusion of liquid molecules into the air (diffusion part) and flow of the liquid molecules from inside the drop to the free outer shell liquid layer within the liquid-vapor interface (evaporation part). The diffusion part remained steady during drying and was not sensitive to the variation of temperature. The evaporation part, however, was an active factor and determined the differences in drop evaporation behaviors. PMID:16853660

Fang, Xiaohua; Li, Bingquan; Petersen, Eric; Ji, Yuan; Sokolov, Jonathan C; Rafailovich, Miriam H

2005-11-01

417

Multi-leg heat pipe evaporator  

NASA Technical Reports Server (NTRS)

A multileg heat pipe evaporator facilitates the use and application of a monogroove heat pipe by providing an evaporation section which is compact in area and structurally more compatible with certain heat exchangers or heat input apparatus. The evaporation section of a monogroove heat pipe is formed by a series of parallel legs having a liquid and a vapor channel and a communicating capillary slot therebetween. The liquid and vapor channels and interconnecting capillary slots of the evaporating section are connected to the condensing section of the heat pipe by a manifold connecting liquid and vapor channels of the parallel evaporation section legs with the corresponding liquid and vapor channels of the condensing section.

Alario, J. P.; Haslett, R. A. (inventors)

1986-01-01

418

Contribution of impervious surfaces to urban evaporation  

NASA Astrophysics Data System (ADS)

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

Ramamurthy, P.; Bou-Zeid, E.

2014-04-01

419

Portion of Enhanced 360-degree Gallery Pan  

NASA Technical Reports Server (NTRS)

This is a sub-section of the 'geometrically improved, color enhanced' version of the 360-degree panorama heretofore known as the 'Gallery Pan', the first contiguous, uniform panorama taken by the Imager for Mars Pathfinder (IMP) over the course of Sols 8, 9, and 10. Different regions were imaged at different times over the three Martian days to acquire consistent lighting and shadow conditions for all areas of the panorama.

The IMP is a stereo imaging system that, in its fully deployed configuration, stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters. In this geometrically improved version of the panorama, distortion due to a 2.5 degree tilt in the IMP camera mast has been removed, effectively flattening the horizon.

The IMP has color capability provided by 24 selectable filters -- twelve filters per 'eye'. Its red, green, and blue filters were used to take this image. The color was digitally balanced according to the color transmittance capability of a high-resolution TV at the Jet Propulsion Laboratory (JPL), and is dependent on that device. In this color enhanced version of the panorama, detail in surface features are brought out via changes to saturation and intensity, holding the original hue constant. A threshold was applied to avoid changes to the sky.

At left is a Lander petal and a metallic mast which is a portion of the low-gain antenna. Misregistration in the antenna and other Lander features is due to parallax in the extreme foreground. Another Lander petal is at the right, showing the fully deployed forward ramp.

Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

1997-01-01

420

Mortality patterns following downsizing at Pan American World Airways.  

PubMed

There are only a small number of studies on the health effects of involuntary unemployment (e.g., downsizing), and results are contradictory. The authors studied the mortality through 2002 of 13,370 Pan American World Airways employees who were born before 1940 and whose records were available after the company's bankruptcy in 1991. The cohort was divided into those who left work voluntarily (55%), involuntarily (39%), and because of illness (6%). The mean year of first employment was 1963, the mean year of last employment was 1987, and the mean age at leaving the company was 55 years. Of those who left involuntarily, 56% left at the time of bankruptcy in December 1991 or later. Twenty-two percent of the cohort died during follow-up, which began at the time of leaving the company. Standardized mortality ratios relative to the US population for all causes for those who left voluntarily, involuntarily, and because of illness were 0.72 (95% confidence interval (CI): 0.69, 0.76), 0.69 (95% CI: 0.65, 0.74), and 2.40 (95% CI: 2.22, 2.60), respectively. Ischemic heart disease mortality showed a similar pattern. Internal analyses comparing involuntary to voluntary leavers after adjusting for age, race, sex, calendar time, and education yielded all-cause and ischemic heart disease rate ratios of 0.96 (95% CI: 0.87, 1.07) and 1.11 (95% CI: 0.93, 1.35), respectively. Subanalyses of those who left involuntarily at age >/=60 years, or those who left involuntarily at the time of bankruptcy, did not indicate any excess mortality (all-cause standardized mortality ratios = 0.69 and 0.64, respectively). These data do not indicate that mortality among those who left involuntarily was higher than for those who left voluntarily. Both groups showed a strong healthy worker effect. PMID:18006901

Steenland, Kyle; Pinkerton, Lynne E

2008-01-01

421

Structural Oil Pan With Integrated Oil Filtration And Cooling System  

DOEpatents

An oil pan for an internal combustion engine includes a body defining a reservoir for collecting engine coolant. The reservoir has a bottom and side