Sample records for pan evaporation rates

  1. Temporal and spatial patterns of pan evaporation in South Korea

    NASA Astrophysics Data System (ADS)

    Jeon, S.; Ryu, Y.

    2012-12-01

    Pan evaporation determines atmospheric demand for evaporation. Several studies reported the decrease of pan evaporation in China in conjunction with global dimming in last several decades. In this study, we investigate the temporal and spatial patterns of pan evaporation measured at 16 stations in South Korea. The data records span 20 to 40 years and we conducted the trend analysis from 1973. We found that pan evaporation has decreased -1.47 mm yr-2 (p<0.05). Solar radiation has increased which does not indicate global dimming. Wind speed has decreased, which was the main factor that decreased pan evaporation. We found that reduction in pan evaporation was stronger in summer and coastal areas. The reduction of pan evaporation was similar in South Korea and China, but with different reasons. Thorough attribution of the reduction in pan evaporation is discussed.

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

    Microsoft Academic Search

    Guobin Fu; Stephen P. Charles; Jingjie Yu

    2009-01-01

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

  3. Pan Evaporation, Relative Humidity and Daily Minimum/Maximum Temperatures

    NSDL National Science Digital Library

    2012-08-03

    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.

  4. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Grading Service 1 Equipment and Utensils § 58.913 Evaporators and vacuum pans. All equipment used in the removal of moisture from milk or milk products for the purpose of concentrating the solids should comply with the requirements of the...

  5. A high-quality monthly pan evaporation dataset for Australia

    Microsoft Academic Search

    Branislava Jovanovic; David A. Jones; Dean Collins

    2008-01-01

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

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

    Microsoft Academic Search

    Hossein Tabari; Safar Marofi; Ali-Akbar Sabziparvar

    2010-01-01

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

  7. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...pans or both, with open type condensers shall be...Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers are used...condensing of product (cow water) in this...

  8. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...pans or both, with open type condensers shall be...Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers are used...condensing of product (cow water) in this...

  9. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...pans or both, with open type condensers shall be...Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers are used...condensing of product (cow water) in this...

  10. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...pans or both, with open type condensers shall be...Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers are used...condensing of product (cow water) in this...

  11. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...pans or both, with open type condensers shall be...Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans. When enclosed type condensers are used...condensing of product (cow water) in this...

  12. Modeling Pan Evaporation for Kuwait by Multiple Linear Regression

    PubMed Central

    Almedeij, Jaber

    2012-01-01

    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

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

    Microsoft Academic Search

    O. Terzi

    2011-01-01

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

  14. Rate of runaway evaporative cooling

    SciTech Connect

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

    2011-09-15

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

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

    Microsoft Academic Search

    J. Vila; C. van Heerwaarden

    2009-01-01

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

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

    Microsoft Academic Search

    Ali Rahimi Khoob

    2008-01-01

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

  17. Inconsistency in Chinese solar radiation data caused by instrument replacement: Quantification based on pan evaporation observations

    NASA Astrophysics Data System (ADS)

    Yang, Hanbo; Li, Zhe; Li, Mingliang; Yang, Dawen

    2015-04-01

    Solar radiation determines our climate and hydrological cycle, and it has been widely measured by pyrometers at meteorological stations. In the early 1990s, a large-scale instrument replacement occurred across China, leading to inconsistent solar radiation observations. Fortunately, China has consistent pan evaporation (Epan) observations from Chinese micropans (with a diameter of 20 cm) from the 1950s to 2001. This study parameterized the PenPan-20 model for estimating Epan from these pans using a Bayesian approach. Furthermore, based on the PenPan-20 model, a shift in the solar radiation data (~1.4 ± 0.5 MJ/(d m2) or 16 ± 7 W/m2) in the early 1990s was revealed; this change was likely due to the large-scale retrofitting of new instruments and irregular calibration operations.

  18. Evaporation rate of water in hydrophobic confinement

    PubMed Central

    Sharma, Sumit; Debenedetti, Pablo G.

    2012-01-01

    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

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

    Microsoft Academic Search

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

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

  20. 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...

  1. Black hole evaporation rates without spacetime.

    PubMed

    Braunstein, Samuel L; Patra, Manas K

    2011-08-12

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

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

    NASA Astrophysics Data System (ADS)

    Mosaedi, Abolfazl; Ghabaei S., Mohammad

    2010-05-01

    Evaporation and Evapotranspiration Process are the major components of the hydrologic cycle which play an important role in agricultural studies such as design of irrigation and drainage systems, and irrigation scheduling. Evapotranspiration is a complex non-linear phenomenon which depends on several climatologic factors. It can be measured directly by high-cost micrometeorological techniques. Hence, many mathematical models and empirical equations were developed to estimate this phenomenon. One conventional method to estimate reference crop evapotranspiration (ET0) is converting the class A pan evaporation (EPan) into ETo by using a pan coefficient (KPan) according to following this equation. ETo = Kpan * Epan PIC Another alternative method to estimate ETo is the application of mathematical models like artificial neural networks (ANNs). ANNs are mathematical models whose architecture has been inspired by biological neural networks. ANNs are very appropriate for the modeling of nonlinear processes, i.e. the case of ETo.Kpan is the important factor for computation of ETo from Epan, There for several empirical equations purposed to determine KPan, using wind speed, relative humidity and fetch length conditions by many researchers. The main objective of this study was to comparison between ability of ANNs and empirical equations for estimation daily ET0 from Epan. For this object Daily measured weather data for a 16 year (from 1992 to 2007) period were obtained from the Shiraz synoptic station (latitude 29o 36' N, longitude 52o 32' E, elevation 1480 m) that located in Fars province of Iran. The climate in the study area is semi-arid with an average annual rainfall of 346 mm year-1. In This paper first, we use seven empirical equations: Cuenca (1989), Snyder (1992), Modified Snyder (1992), Doorenbos and Pruitt (1977), Pereira et al. (1995), Orang (1998) and Raghuwanshi and Wallender (1998) for estimation KPan values and second then we use ANNs for converting Epan to estimate ET0 as a function of the wind speed and relative humidity for the mentioned station. The comparisons and performance of both ANN and the conventional method have been based on statistical error techniques, using FAO Penman Monteith method (PM56) daily ETo values as a reference. The PM56 is the standard method for the calibration of other ETo estimation equations when there is no measured lysimeter data. The results show that among the seven approaches Snayder (1992) gave a better performance values (R2=0.45 and RMSE=3.36 mm day-1) and Pereira et al. (1995) gave a poor performance under the case study. ANNs have obtained better results than the seven empirical equations values (R2=0.901 and RMSE=0.96 mm day-1). Keywords: evapotranspiration, pan evaporation, ANN, empirical equations, Shiraz

  3. Evaporation

    NSDL National Science Digital Library

    James H. Kessler

    2007-01-01

    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.

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

    Microsoft Academic Search

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

    2011-01-01

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

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

    USGS Publications Warehouse

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

    2005-01-01

    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.

  6. Absolute evaporation rates of non-rotating neutral PAH clusters

    E-print Network

    Montillaud, Julien

    2014-01-01

    Clusters of polycyclic aromatic hydrocarbons (PAHs) have been proposed as candidates for evaporating very small grains, which are thought to be precursors of free-flying PAHs. Evaporation rates have been calculated so far only for species containing up to a few 100 C atoms, whereas interstellar PAH clusters could contain up to ~1000 C atoms. We present a method that generalises the calculation of the statistical evaporation rate of large PAH clusters and provides rates for species containing up to ~1000 C-atoms. The evaporation of non-rotating neutral homo-molecular PAH clusters containing up to 12 molecules from a family of highly symmetric compact PAHs is studied. Statistical calculations were performed and completed with molecular dynamics simulations at high internal energies to provide absolute values for the evaporation rate and distributions of kinetic energy released. The calculations used explicit atom-atom Lennard-Jones potentials in the rigid molecule approximation. A new method is proposed to take...

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

    SciTech Connect

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

    1995-03-01

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

  8. Priority of the Mn Deposition Rate in Reactive Evaporation Conditions

    Microsoft Academic Search

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

    2000-01-01

    Manganese (Mn) oxide films used in lithium secondary batteries were prepared using the reactive evaporation method. One of the problems of using this method is that the manganese evaporant in the crucible suffers oxidation in an oxygen atmosphere. This deteriorates the Mn deposition rate with increasing the deposition run. A separator was introduced in the bottom of the Mn crucible.

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

    E-print Network

    . Several such methods (Penman­Monteith (PM), modified Priestley­Taylor (PT), reference evapotranspiration bulk surface conductance, PT a, ET0 vegetation coefficient, and Ep pan coefficient. The PT method relation with ETa (standard error (SE) for daily ETa of 0.11 mm). The PM method, in which the bulk surface

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  11. Rate of Water Evaporation in Texas. 

    E-print Network

    Karper, R. E. (Robert Earl)

    1933-01-01

    . Av. rel. humidity Wind run, miles Winter Haven : 18 7 7 5 63 32 47 3629 3.346 i -94 76.8 52.8 64.8 80.4 4343 Evaporation, inches Precipitation, inches 5.520 1.11 80.1 57.2 68.7 75.6 5558 2.252 .82 2 1 1.824 11 1 1.16 4....560 7.341 8.897 8.152 9.196 8.725 8.469 6.825 7.965 5.280 7.241 5.468 7.435 4.221 5.526 5.011 5.991 4.454 5.797 6.044 5.671 6.167 5.684 '7.377 4.801 5.052 6.216 4.086 2.912 3.891 5.557 4.850 13.820 3.804 3.956 4.173 6...

  12. Urban evaporation rates for water-permeable pavements.

    PubMed

    Starke, P; Göbel, P; Coldewey, W G

    2010-01-01

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

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

    Microsoft Academic Search

    Abolfazl Mosaedi; Mohammad Ghabaei S

    2010-01-01

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

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

    Microsoft Academic Search

    Merv F. Fingas

    1997-01-01

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

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

    Microsoft Academic Search

    Akira Tsuchiyama; Shogo Tachibana; Toshio Takahashi

    1999-01-01

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

  16. Priority of the Mn Deposition Rate in Reactive Evaporation Conditions

    NASA Astrophysics Data System (ADS)

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

    2000-12-01

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

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

    USGS Publications Warehouse

    Masoner, Jason R.; Stannard, David I.

    2010-01-01

    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.

  18. Calculation of Reactive-evaporation Rates of Chromia

    SciTech Connect

    Holcomb, G.R.

    2008-04-01

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

  19. Correlation of chemical evaporation rate with vapor pressure.

    PubMed

    Mackay, Donald; van Wesenbeeck, Ian

    2014-09-01

    A new one-parameter correlation is developed for the evaporation rate (ER) of chemicals as a function of molar mass (M) and vapor pressure (P) that is simpler than existing correlations. It applies only to liquid surfaces that are unaffected by the underlying solid substrate as occurs in the standard ASTM evaporation rate test and to quiescent liquid pools. The relationship has a sounder theoretical basis than previous correlations because ER is correctly correlated with PM rather than P alone. The inclusion of M increases the slope of previous log ER versus log P regressions to a value close to 1.0 and yields a simpler one-parameter correlation, namely, ER (?g m(-1) h(-1)) = 1464P (Pa) × M (g mol(-1)). Applications are discussed for the screening level assessment and ranking of chemicals for evaporation rate, such as pesticides, fumigants, and hydrocarbon carrier fluids used in pesticide formulations, liquid consumer products used indoors, and accidental spills of liquids. The mechanistic significance of the single parameter as a mass-transfer coefficient or velocity is discussed. PMID:25105222

  20. Aerosol synthesis of lipid nanoparticles: Relating crystallinity to simulated evaporation rates

    Microsoft Academic Search

    Manish Shetty; Amol A. Pawar; Anurag Mehra; Chandra Venkataraman

    2012-01-01

    The degree of crystallinity of nanometre size lipid matrices governs drug loading and release rates. Recently, droplet-phase aerosol synthesis was used to prepare lipid nanoparticles of stearic acid and achieve control over their crystallinity using precursor solvents with differing vapour pressures. The present work aims at examining relationships between solvent evaporation rate and extent of evaporative cooling, during drop evaporation,

  1. A Mass Function Constraint on Extrasolar Giant Planet Evaporation Rates

    E-print Network

    W. B Hubbard; M. Hattori; A. Burrows; I. Hubeny

    2007-02-09

    The observed mass function for all known extrasolar giant planets (EGPs) varies approximately as M^{-1} for mass M between 0.2 Jupiter masses (M_J) and 5 M_J. In order to study evaporation effects for highly-irradiated EGPs in this mass range, we have constructed an observational mass function for a subset of EGPs in the same mass range but with orbital radii mass function for such highly-irradiated EGPs agrees quantitatively with the M^{-1} law, implying that the mass function for EGPs is preserved despite migration to small orbital radii. Unless there is a remarkable compensation of mass-dependent orbital migration for mass-dependent evaporation, this result places a constraint on orbital migration models and rules out the most extreme mass loss rates in the literature. A theory that predicts more moderate mass loss gives a mass function that is closer to observed statistics but still disagrees for M < 1 M_J.

  2. WilsonBull., 105(4), 1993, pp. 645-656 METABOLIC RATE AND EVAPORATIVE WATER

    E-print Network

    to dissipate heat via evaporative cooling may partially explain its tendency to use habitats featuring coolWilsonBull., 105(4), 1993, pp. 645-656 METABOLIC RATE AND EVAPORATIVE WATER LOSS OF MEXICAN SPOTTED of oxygen consumption and evaporative water loss (EWL) of Mexican Spotted (Strix occidentalislucida

  3. Evaporation rates of alkanes and alkanols from acoustically levitated drops

    Microsoft Academic Search

    Rudolf Tuckermann; Sigurd Bauerecker; Bernd Neidhart

    2002-01-01

    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

  4. The development of a new evaporation formula for Texas 

    E-print Network

    Moe, R. D

    1965-01-01

    computers are now used to deduce the best man- agement of the water in the reservoirs. An engineer must choose a dam site with the greatest care. Shallow lakes in an area with a high evaporation rate are uneconomical because ot the large surface area... pans than from lakes. The Young screen pan was first used by the Division of Irrigation in 1936. Evaporation from this pan occurs at about the same rate as from a reservoir [2] . The Texas Board of Water Engineers, in cooperation with the Texas...

  5. Atmospheric evaporative demand observations, estimates and driving factors in Spain (1961-2011)

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, Cesar; Vicente-Serrano, Sergio M.; Sanchez-Lorenzo, Arturo; McVicar, Tim R.; Morán-Tejeda, Enrique; Revuelto, Jesús; El Kenawy, Ahmed; Martín-Hernández, Natalia; Tomas-Burguera, Miquel

    2015-04-01

    We analyzed the spatio-temporal evolution of evaporation observations from Piché atmometers (1961-2011; 56 stations) and Pan evaporimeters (1984-2011; 21 stations) across Spain, and compared both measurements with evaporation estimates obtained by four physical models: i.e., Food and Agricultural Organization-56 Penman-Monteith, Food and Agricultural Organization-Pan, PenPan and Penman, based on climate data. In this study we observed a positive and statistically significant correlation between Piché and Pan evaporation measurements during the common period (1984-2011; 19 stations), mainly in summer. When evaporation observations and estimates were compared, we detected positive and statistically significant correlations with the four methods, except for winter. Among the four physical models, the FAO-Pan showed the best fitting to both Piché and Pan evaporation measurements; the PenPan model overestimated evaporation rates; and the FAO-Penman-Monteith and Penman methods underestimated evaporation observations. We also observed a better spatial agreement between Pan evaporation and estimates than that obtained by Piché measurements. Annual and seasonal trends of evaporation estimates show a statistically significant increase for 1961-2011, which do not agree with long-term Piché evaporation trends; e.g. a discontinuity was found around the 1980s. Radiative and aerodynamic driving factors suggest that this discontinuity, and the observed evaporation trends across Spain could be associated with the abrupt increase in air temperature observed during last few decades (i.e., global warming). Further investigations using available Piché evaporation observations for other regions are needed to better understand physical components influencing long-term trends of evaporation.

  6. Water budgets of Italian and Dutch gravel pit lakes: a study using a fen as a natural evaporation pan, stable isotopes and conservative tracer modeling.

    NASA Astrophysics Data System (ADS)

    Nella Mollema, Pauline; Antonellini, Marco

    2015-04-01

    Gravel pits are excavated in aquifers to fulfill the need for construction materials. Flow-through lakes form where the gravel pits are below the water table and fill with groundwater. Their presence changes the drainage patterns, water- and hydrochemical budgets of a watershed. We have studied the water budget of two gravel pit lakes systems using stable H and O isotopes of water as well as conservative tracer (Cl) modeling. The Dutch gravel pit lakes are a fluvial fresh water system of 70 lakes along the Meuse River and the Italian gravel pit lakes are a brackish system along the Adriatic coast. Surface water evaporation from the gravel pit lakes is larger than the actual evapotranspiration of the grass land and forests that were replaced. The ratio of evaporation to total flow into the Dutch lakes was determined by using a Fen as a natural evaporation pan: the isotope content of the Tuspeel Fen, filled with rain water and sampled in a dry and warm summer period (August 2012), is representative for the limiting isotopic enrichment under local hydro meteorological conditions. The Local Evaporation line (LEL) was determined ?2 H = 4.20 ? 18O - 14.10 (R² = 0.99) and the ratio of total inflow to evaporation for three gravel pit lakes were calculated to be 22.6 for the De Lange Vlieter lake used for drinking water production, 11.3 for the Boschmolen Lake and 8.9 for the Anna's Beemd lake showing that groundwater flow is much larger than evaporation. The Italian gravel pit lakes are characterized by high salinity (TDS = 4.6-12.3 g L-1). Stable isotope data show that these latter gravel pit lakes are fed by groundwater, which is a mix between fresh Apennine River water and brackish (Holocene) Adriatic Sea water. The local evaporation line is determined: ?2H = 5.02 ?18O - 10.49. The ratio of total inflow to evaporation is 5. Conservative tracer modeling indicates that the chloride concentration in the Italian gravel pit lakes stabilizes after a short period of rapid increase, because water leaving the lake via groundwater flow, driven by the drainage system, removes part of the Cl that accumulates in the lake due to evapo-concentration. Under climate change, rising sea levels and continuing land subsidence as well as increasing precipitation would increase the need for drainage which would enhance groundwater flow through the lake. The resulting steady-state Cl concentration of the lakes could become less than the current Cl concentration. This effect would be larger than increasing evapo- concentration. Both gravel pit lake systems have a large flux of groundwater into and out of the lakes driven by evaporation and (artificial) drainage with important consequences for the water- and hydrochemical budgets of the whole watershed and in particular on freshwater quantity and groundwater salinity.

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

    NASA Astrophysics Data System (ADS)

    Montillaud, J.; Joblin, C.

    2014-07-01

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

  8. Effect of UV irradiation on the evaporation rate of alcohols droplets

    NASA Astrophysics Data System (ADS)

    Korobko, O. V.; Britan, A. V.; Verbinskaya, G. H.; Gavryushenko, D. A.

    2015-06-01

    The effect of ultraviolet irradiation with a wavelength of 390 nm on the evaporation of droplets of the homologous series of alcohols ( n-propanol, n-butanol, n-pentanol, n-heptanol, n-octanol, and n-decanol) at 10, 30, 50, 100, and 200 mm Hg in an atmosphere of dry nitrogen is studied. The values of the evaporation rate of alcohols are calculated with and without irradiation. Starting from n-pentanol, the rate of evaporation grows strongly for droplets of higher alcohols under the effect of low-power irradiation not associated with the heating of the evaporating droplets of alcohols. The obtained results are analyzed by comparing them to experimental data on neutron scattering by alcohols. It is shown that free convection must be considered in order to describe the evaporation process. Expressions of different authors for describing this effect are analyzed.

  9. High Rate Preparation of aSi:H by Reactive Evaporation Method

    Microsoft Academic Search

    Masanari Shindo; Shigeru Sato; Isao Myokan; Shigeru Mano; Takuji Shibata

    1984-01-01

    A high rate deposition method of a-Si: H based on reactive evaporation is described. a-Si: H prepared at a deposition rate of 30 Å\\/sec has much the same photoconductivity as films prepared by the glow discharge (GD) method. It is revealed that silicon oxidation due to residual oxygen gas is suppressed using a method of silicon evaporation to supply hydrogen

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

    NASA Technical Reports Server (NTRS)

    Xiong, Yong-Liang; Hewins, Roger H.

    2003-01-01

    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.

  11. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    NASA Astrophysics Data System (ADS)

    Bilde, M.; Zardini, A. A.; Hong, J.; Tschiskale, M.; Emanuelsson, E.

    2014-12-01

    The atmospheric partitioning between gas and condensed phase of organic molecules is poorly understood, and discrepancies exist between predicted and observed concentrations of secondary organic aerosols. A key problem is the lack of information about thermodynamic properties of semi- and low volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar alcohols. These polyols are common in the water soluble fraction of atmospheric aerosols. In our experimental system sub-micron particles are generated by nebulization from aqueous solution, and a mono disperse fraction of the aerosol is selected using a differential mobility analyzer. The particles are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using thermodynamic modeling. Results are presented and discussed in context of atmospheric gas to particle partitioning.

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

    Microsoft Academic Search

    Tadatsugu Minami; Satoshi Ida; Toshihiro Miyata

    2002-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  14. Evaporation rates of freely falling liquid nitrogen droplets in air

    SciTech Connect

    Awonorin, S.O.

    1989-01-01

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

  15. Evaporation rate and composition monitoring of electron beam PVD processes

    SciTech Connect

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

    1995-03-01

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

  16. Evaporation rate from square capillaries limited by corner flow viscous losses

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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.

  17. 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...

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

    SciTech Connect

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

    2007-06-15

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

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

    Microsoft Academic Search

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

    1993-01-01

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

  20. Combining the Penman-Monteith equation with measurements of surface temperature and reflectance to estimate evaporation rates of semiarid grassland

    Microsoft Academic Search

    A. F. Rahman; J. C. Washburne; M. A. Weltz; W. P. Kustas

    The Penman-Monteith equation is useful for computing evaporation rates of uniform surfaces, such as dense vegetation or bare soil. This equation becomes less useful for evaluation of evaporation rates at the regional scale, where surfaces are generally characterized by a patchy combination of vegetation and soil. This is particularly true in the arid and semi-arid regions of the world. The

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

    PubMed

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

    2015-03-17

    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

  2. Predictions of evaporative-loss rates of solutes in stagnant and turbulent waters in relation to rates of reference materials

    SciTech Connect

    Chiou, C.T.; Kohnert, R.L.; Freed, V.H.; Tonkyn, R.G.

    1983-01-01

    A previously published kinetic model for evaporative rates of substances into air leads to the estimation of the dependence of solute-transfer coefficients on turbulence applied to the system. The ratios of the transfer coefficients of all solutes become insensitive to air turbulence and to water mixing either when they have comparable Henry's law constants or when their Henry's law constants are sufficiently low, but not otherwise. Confirming data are presented and methods for simplifying the estimation of transfer coefficients are discussed.

  3. Effects Of Evaporation Rate of Some Common Organic Contaminants on Hydraulic Conductivity of Aquifer Sand

    NASA Astrophysics Data System (ADS)

    Saud, Q. J.; Hasan, S. E.

    2014-12-01

    As part of a larger study to investigate potential effects of hydrocarbons on the geotechnical properties of aquifer solids, a series of laboratory experiments were carried out to ascertain the influence of evaporation rate of some common and widespread organic contaminants on the hydraulic conductivity of aquifer sand. Gasoline and its constituent chemicals-benzene, toluene, ethylbenzene, xylene (BTEX), isooctane- and trichloroethylene (TCE) were used to contaminate sand samples collected from the aquifer and vadose zone, at varying concentrations for extended periods of time. The goal was to study any change in the chemical makeup of the contaminants and its control on hydraulic conductivity of the sand. It was found that: (a) gasoline breaks down into constituent compounds when subjected to evaporation, e.g. during oil spills and leaks; and (b) lighter compounds volatilize faster and in the following order: TCE> benzene > isooctane > toluene > gasoline> ethylbenzene > xylene. In addition, these contaminants also caused a decrease in hydraulic conductivity of sand by up to 60% as compared to the uncontaminated sand. The inherent differences in the chemical structure of contaminating chemicals influenced hydraulic conductivity such that the observed decrease was greater for aliphatic than aromatic and chlorinated hydrocarbons. The presentation includes details of the experimental set up; evaporation rate, and geotechnical tests; X-ray diffraction and scanning electron microscope studies; and data analyses and interpretation. Rate of evaporation test indicates that residual LNAPLs will occupy a certain portion of the pores in the soil either as liquid or vapor phase in the vadose zone, and will create a coating on the adjacent solid mineral grains in the aquifer. Replacement of air by the LNAPLs along with grain coatings and the intramolecular forces would impede groundwater movement, thus affecting overall permeability of contaminated aquifers. Keywords: aquifer sand, hydraulic conductivity, BTEX, gasoline, LNAPLs, isooctane

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  5. Novel in situ method for locating virtual source in high-rate electron-beam evaporation

    NASA Astrophysics Data System (ADS)

    Bhatia, M. S.

    1994-07-01

    The concept of virtual source simplifies calculation of thickness distribution on extended substrates in high rate vacuum coating employing electron-beam heating. The height of the point (virtual source), from which vapor can be assumed to emanate in accordance with Knudsen's cosine law, to yield the experimentally obtained thickness distribution, is calculated and this establishes the position of virtual source. Such as post facto determination is cumbersome as it is valid for the prescribed material evaporating at a certain rate in a specified geometry. A change in any of these entails a fresh measurement. Experimenters who use a large number of materials and deposit at different rates therefore have to carry out a number of trials before they can locate the virtual source at the desired deposition parameters. An in situ method for obtaining virtual source position can go a long way in reducing the labor of these experiments. A novel in situ method is described to locate the virtual source.

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

    NASA Astrophysics Data System (ADS)

    Jodat, Amin; Moghiman, Mohammad; Shirkhani, Golshad

    2013-12-01

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

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

    E-print Network

    Cao, Guozhong

    Nano-structured Li3V2(PO4)3/carbon composite for high-rate lithium-ion batteries Anqiang Pan a September 2010 Available online 22 September 2010 Keywords: Li-ion batteries Cathode Vanadium phosphate Li3V batteries. © 2010 Published by Elsevier B.V. 1. Introduction Rechargeable Li-ion batteries are the power

  8. Milagro limits and HAWC sensitivity for the rate-density of evaporating primordial black holes

    DOE PAGESBeta

    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.; et al

    2015-04-01

    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 × 10¹? 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 tomore »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.« less

  9. Influence of the stellar mass function of the evaporation rate of tidally limited postcollapse globular clusters

    NASA Astrophysics Data System (ADS)

    Lee, Hyung Mok; Goodman, Jeremy

    1995-04-01

    We study the rate of escape of stars (evaporation) from tidally limited postcollapse globular clusters having a power-law distribution of stellar masses. We use a multimass Fokker-Planck code and assume a steady tidal field. Stellar-dynamical processes cause the inner parts of the cluster to expand, which in turn causes stars to overflow the tidal boundary. Mass loss by stellar evolution is assumed to be unimportant in these later evolutionary stages. The fraction of the cluster mass lost per half-mass relaxation time trh is roughly constant, in agreement with simple homologous models with equal-mass stars. If trh is computed in the conventional way from the mean stellar mass, however, a broad stellar mass function can double the loss of mass per trh. We discuss implications of our results for the evolution of globular cluster systems in our own and other galaxies. In particular, the number of Galactic clusters destroyed by evaporation alone may be as large as or larger than the present population.

  10. OLPPS PAN Reviewer Who is a PAN

    E-print Network

    Yamamoto, Keith

    OLPPS PAN Reviewer Who is a PAN Reviewer? Each department identifies specific individuals to be PAN Reviewers. An individual may be designated to review PAN notices for EDB transactions, OPTRS transactions, or both. Departments are required to have at least one mandatory and one backup PAN Reviewer. Why is a PAN

  11. Growth rates of atmospheric molecular clusters determined from cluster appearance times and collision-evaporation fluxes

    NASA Astrophysics Data System (ADS)

    Kontkanen, Jenni; Olenius, Tinja; Lehtipalo, Katrianne; Vehkamäki, Hanna; Kulmala, Markku

    2015-04-01

    The probability of freshly formed particles to survive to climatically relevant sizes is determined by the competition between the coagulation loss rate and the particle growth rate. Therefore, various methods have been developed to deduce the growth rates from measured particle size distributions. Recently, the growth rates of sub-3nm clusters have been determined based on the appearance times of different cluster sizes. However, it is not clear to what extent these growth rates are consistent with the growth rates corresponding to molecular fluxes between clusters. In this work, we simulated the time evolution of a population of sub-3 nm molecular clusters and compared the growth rates determined (1) from the cluster appearance times and (2) from the collision-evaporation fluxes between different cluster sizes. We performed a number of simulations by varying the ambient conditions and the properties of the model substance. In the first simulation set, the Gibbs free energy of the formation of the clusters was assumed to have a single maximum and no minima, corresponding to a monotonically increasing stability as a function of cluster size. The saturation vapor pressure was selected so that the growth proceeded solely via monomer additions. The growth rates were determined separately for each cluster. However, to see the effect of finite size resolution, we also performed simulations where the clusters were grouped into size bins, for which we determined the growth rates. In the second simulation set, the saturation vapor pressure was lowered so that the collisions of small clusters significantly contributed to the growth. As the growth rate of a single cluster is ambiguous in this case, the growth rates were determined only for different size bins. We performed simulations using a similar free energy profile as in other simulations but we also used a free energy profile containing a local minimum, corresponding to small stable clusters. Our simulations show that there may be significant differences between the growth rates determined with the two approaches. The growth rates determined from the appearance times of clusters were generally higher than the flux-equivalent growth rates. The difference between the growth rates was largest for the smallest clusters but its magnitude varied depending on the properties of the model substance and on the ambient conditions, such as the external sink. The use of size bins increased the difference, especially if the width of the size bins was large. In the simulations where non-monomer collisions significantly contributed to the growth, the difference between the two growth rates was smallest in the conditions with high cluster concentrations. Furthermore, when the free energy profile had a minimum, the difference was generally smaller than in the simulations with no minima. While this work assesses the qualitative behavior of the size-dependent growth rates, and calls for caution in the interpretation of growth rates deduced from experiments, quantitative comparisons require information on the specific substance and conditions of interest.

  12. Differences in metabolic rate and evaporative water loss associated with sexual dimorphism in thynnine wasps.

    PubMed

    Tomlinson, Sean; Phillips, Ryan D

    2015-07-01

    Species with sexual dimorphism provide powerful study systems for understanding adaptation to different lifestyles as it removes the potentially confounding effects of phylogeny. Thynnine wasps have a stark sexual dimorphism where males fly patrols in search of the flightless, predominantly fossorial females with which to mate. Using flow-through respirometry, we tested the prediction that the highly active males of the thynnine wasp Zaspilothynnus nigripes would have high metabolic rates (VCO2) relative to females. Further, the females, which spend more time underground, were predicted to exhibit lower evaporative water loss (EWL) than males. Metabolic rate of both sexes increased exponentially between 12 and 28°C. As predicted, males had higher mass-corrected VCO2 at identical temperatures than females. Alternatively, there were no differences in the EWL at identical temperatures between sexes, suggesting that experiencing the same environmental conditions during mating may favour similar EWL. Interestingly, Z. nigripes were estimated to undergo a decrease in metabolism at approximately 30°C. It is proposed that Z. nigripes persist despite sensitivity to high temperatures using a combination of behavioural strategies and emergence during a period of relatively benign climate that ameliorates the impacts of high temperatures. PMID:25935839

  13. An Automatic Sensor-Controlled Evaporation and Rainfall Measurement System

    Microsoft Academic Search

    Turkay Onacak; Mehmet Tekin Yurur

    2011-01-01

    For the efficient management of water, meteorological and hydrological services need to know how much water evaporates from natural lakes and reservoirs during particularly hot summer months. Following the technical requirements of the World Meteorological Organization on use of an evaporation pan for this purpose, we improved the use of the classical evaporation pan to measure at any time, with

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

    Microsoft Academic Search

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

    1984-01-01

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

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

    PubMed

    Salvucci, Guido D; Gentine, Pierre

    2013-04-16

    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

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

    NASA Astrophysics Data System (ADS)

    Rafkin, Scot C. R.

    2012-10-01

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

  17. Evaporation Rate of Water as a Function of a Magnetic Field and Field Gradient

    PubMed Central

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

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Zhang, Nengli; Chao, David F.

    1999-01-01

    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.

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

    Microsoft Academic Search

    EUGENE H. STUDIER

    1976-01-01

    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

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

    Microsoft Academic Search

    K. V. Beard; H. R. Pruppacher

    1971-01-01

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

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

    Microsoft Academic Search

    Mahboubeh Fazaeli; Ghazale Hojjatpanah; Zahra Emam-Djomeh

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

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

    NASA Astrophysics Data System (ADS)

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

    1985-01-01

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

  3. Measuring forest evaporation and transpiration rates with fibre optic temperature sensing

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  4. Characteristics of Evaporation Rate of Water in Superheated Steam and Air

    NASA Astrophysics Data System (ADS)

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

    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.

  5. Quantifying the feedback of evaporation and transpiration rates to soil moisture dynamics and meteorological condition changes by a numerical model

    NASA Astrophysics Data System (ADS)

    Su, Ye; Shao, Wei; Vl?ek, Lukáš; Langhammer, Jakub

    2015-04-01

    Evapotranspiration drives the hydrological process through energy-driven water-phase changes between systems of soil-vegetation-atmosphere. Evapotranspiration performs a rather complex process attributable to the spatial and temporal variation of soil-vegetation-atmosphere system. For vegetation-covered land surfaces, the transpiration process is governed by the stomatal behavior and water uptake from the root zone, and evaporation is related with the interception of rainfall and radiation on the canopy and soil surface. This study is emphasized on describing the hydrological process and energy cycle in a basic hydrological response unit, a hillslope. The experimental hillslope is located in an experimental catchment of the Bohemian Forest Mountains' headwaters in the Czech Republic, where is mostly covered by dead Norway spruce forest (Picea abies) stands caused by balk beetle outbreak. High-frequency monitoring network of the hydro-climatic data, soil pore water pressure and soil temperature has been launched since 2012. To conceptualize the land-surface energy and water fluxes in a complex hillslope, a soil-vegetation-atmosphere transport (SVAT) model, coupled with a multi-phase soil physics process (i.e. the water, vapor and heat flow transport) is used. We selected an 8-week basis dataset from 2013 as a pilot for partitioning the evapotranspiration into three interactive components: transpiration (Et), canopy interception evaporation (Ei), and soil evaporation (Es), by using this numerical model. Within such model framework, the sensitive feedback of evapotranspiration rates to rainfall intensity, soil moisture, and solar radiation will be examined by conducting numerical experiments to better understand the mechanism of evapotranspiration process under various influencing factors. Such application study and followed numerical simulations provide a new path for quantifying the behaviors of the soil-vegetation-atmosphere system.

  6. Effects of oxygen flow rate on microstructure and optical properties of aluminum oxide films deposited by electron beam evaporation technique

    Microsoft Academic Search

    Namita Maiti; A. Biswas; R. B. Tokas; D. Bhattacharyya; S. N. Jha; U. P. Deshpande; U. D. Barve; M. S. Bhatia; A. K. Das

    2010-01-01

    Reactive evaporation technique has been used to deposit thin films of alumina (Al2O3) on crystalline Si substrates at ambient temperatures in an electron beam (e-beam) evaporation system using alumina granules as evaporant material. The loss of oxygen due to dissociation of alumina has been compensated by bleeding high purity oxygen gas into the system during evaporation. A set of samples

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

    SciTech Connect

    Hsu, Irving; Mills, Bernice E.

    2010-08-01

    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.

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

    PubMed

    Gevelber, Michael; Xu, Bing; Smith, Douglas

    2006-03-01

    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

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

    SciTech Connect

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

    1984-01-01

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

  10. Group evaporation

    NASA Technical Reports Server (NTRS)

    Shen, Hayley H.

    1991-01-01

    Liquid fuel combustion process is greatly affected by the rate of droplet evaporation. The heat and mass exchanges between gas and liquid couple the dynamics of both phases in all aspects: mass, momentum, and energy. Correct prediction of the evaporation rate is therefore a key issue in engineering design of liquid combustion devices. Current analytical tools for characterizing the behavior of these devices are based on results from a single isolated droplet. Numerous experimental studies have challenged the applicability of these results in a dense spray. To account for the droplets' interaction in a dense spray, a number of theories have been developed in the past decade. Herein, two tasks are examined. One was to study how to implement the existing theoretical results, and the other was to explore the possibility of experimental verifications. The current theoretical results of group evaporation are given for a monodispersed cluster subject to adiabatic conditions. The time evolution of the fluid mechanic and thermodynamic behavior in this cluster is derived. The results given are not in the form of a subscale model for CFD codes.

  11. Evaporative climate changes at Bet Dagan, Israel, 1964–1998

    Microsoft Academic Search

    S. Cohen; A. Ianetz; G. Stanhill

    2002-01-01

    Analysis of evaporation measurements made between 1964 and 1998 at Bet Dagan in Israel’s central coastal plain shows a small but statistically significant increase in screened Class A pan evaporation, mainly in the dry, summer half of the year. No changes were found in the total open water evaporation or reference crop evapotranspiraton estimated with Penman’s combined heat balance and

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

    NASA Astrophysics Data System (ADS)

    Oroud, Ibrahim M.

    2011-12-01

    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.

  13. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  14. The contribution of evapotranspiration and evaporation to the water budget of a treatment wetland in Phoenix, AZ, USA

    E-print Network

    Hall, Sharon J.

    loss was much higher than open water evaporative losses measured with evaporation pans. EvaporationThe contribution of evapotranspiration and evaporation to the water budget of a treatment wetland important aspects of any wetland is the water budget. Quantifying how evaporation and evapotranspiration

  15. (10:1, 55 nm) and was deposited by the co-evaporation of magnesium and silver metals, with deposition rates of 5 and 0.5 s1

    E-print Network

    Wang, Zhong L.

    of 3 s±1 . The effective area of the emitting diode was 9.00 mm2 . Current, voltage, and light evaporating LiF (0.5 nm) at a deposition rate of 0.1 s±1 and then evaporating aluminum (400 nm) at a rate

  16. Pan Balance-Numbers

    NSDL National Science Digital Library

    2011-01-01

    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.

  17. 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

    Motasem, Mohamed M

    1964-01-01

    in psrtisl fulfilhasat of the reqoireaests for the deSree of hoSuat 1964 Eager Subject! Hairy Seiessa A ORFkllSW OF TNO TRC8NXQOES FOR NRASORIIO THE REtdXWE RATES OF lOISXORE EFAFORATTON ISO' LQCTEO AREAS OF TNE SHIN OF HOLSTEIN~ JENNET ANO JRRSET... Holstein cows, but that the resistance was not the result of an 1ncreased capacity to evaporate water. Bauer)ee and co~rkers (2) modified the technique of NcDowell et al. (17). They reported that sweating rate, rectal teaperature, respiration rate...

  18. Evaluation of Pan Coefficients for Estimating Reference Evapotranspiration in Southern Taiwan

    NASA Astrophysics Data System (ADS)

    Yeh, H.

    2006-12-01

    Evapotranspiration is an important process of water transfer in the hydrosphere and atmosphere, which plays an active role in the hydrological cycle. Evaporation pan (Epan) data are often used to estimate reference evapotranspiration (ETref) for use in water resource planning. Generally, ETref is estimated as the product of the Epan data and a pan coefficient (Kpan). However, reliable estimation of ETref using Epan depends on the accurate determination of pan coefficients Kpan. Many different methods for estimating ETref have been developed, among which the Penman-Monteith method is demonstrated to be especially excellent by the Food and Agriculture Organization (FAO). In this study, the Penman-Monteith reference evapotranspiration, pan evaporation, and pan coefficient are calculated, compared and regionally mapped at nine meteorological stations during 1990-2004 in Southern Taiwan. The results show the reference evapotranspiration and pan evaporation have similar regional distribution patterns in the southern Taiwan both with the highest values being in the lower region and the lowest values being in the upper region. In addition, the pan coefficient, Kpan, varies both regionally and seasonally. Smallest Kpan values are found in the upper reach of the southern Taiwan, meaning that the relative difference between the reference evapotranspiration and pan evaporation is the biggest in the region, the largest Kpan values are obtained in the western area of southern Taiwan. This distribution pattern provides valuable information for regional hydrological studies since it is one of the most important factors determining regional actual evapotranspiration.

  19. {The rate of water vapor evaporation from ice substrates in the presence of HCl and HBr: implications for the lifetime of atmospheric ice particles

    Microsoft Academic Search

    C. Delval; B. Fluckiger; M. J. Rossi

    2003-01-01

    The rate of evaporation of H_2O, Rev, and its condensation, kcond, on a 1mum thick ice film has been studied in the temperature range 190 to 240K as well as in the presence of small amounts of HCl and HBr that left the vapor pressure of H_2O on ice unchanged. The resulting Arrhenius expressions for pure ice are Rev=8.0\\\\cdot1029± 1\\\\cdot

  20. Evaporation and reference evapotranspiration trends in Spain

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, Arturo; Vicente-Serrano, Sergio M.; Wild, Martin; Azorin-Molina, Cesar; Calbó, Josep; Revuelto, Jesús; López-Moreno, Juan I.; Moran-Tejeda, Enrique; Martín-Hernández, Natalia; Peñuelas, Josep

    2015-04-01

    Interest is growing in the trends of atmospheric evaporation demand, increasing the need for long-term time series. In this study, we first describe the development of a dataset on evaporation in Spain based on long-term series of Piché and pan measurement records. Piché measurements have been reported for >50 stations since the 1960s. Measurements of pan evaporation, which is a much more widely studied variable in the literature, are also available, but only since 1984 for 21 stations. Particular emphasis was placed on the homogenization of this dataset (for more details, we refer to Sanchez-Lorenzo et al., 2014, Clim Res, 61: 269-280). Both the mean annual Piché and pan series over Spain showed evaporative increases during the common study period (1985?2011). Furthermore, using the annual Piché records since the 1960s, an evaporation decline was detected from the 1960s to the mid-1980s, which resulted in a non-significant trend over the entire 1961?2011 period. Our results indicate agreement between the decadal variability of reference evapotranspiration (Vicente-Serrano et al., 2014, Glob Planet Chang, 121: 26-40) and surface solar radiation (Sanchez-Lorenzo et al., 2013, Glob Planet Chang, 100: 343-352) and the evaporation from Piché and pan measurements since the mid-1980s, especially during summer. Nevertheless, this agreement needs attention, as Piché evaporimeters are inside meteorological screens and not directly exposed to radiation. Thus, as Piché readings are mainly affected by the aerodynamic term in Penman's evaporation equation and pan records are affected by both the heat balance and aerodynamic terms, the results suggest that both terms must be highly and positively correlated in Spain. In order to check this hypothesis, the radiative and aerodynamic components were estimated using the Penman's equation. The results show that the relationship with the radiative components is weaker than that with the aerodynamic component for both pan and Piché evaporation measurements. In addition, both component series show an increase during the period 1985?2011, but the aerodynamic term is larger than the radiative term. These results indicate that the increase in evaporation over Spain since the mid-1980s can be related to changes in both terms of the Penman's equation, especially the aerodynamic component, possibly due to a strong decrease in relative humidity in the last decades and a noticeable increase in air temperature (Vicente-Serrano et al. 2014, Water Resour Res 50: 8458-8480)

  1. 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)

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

    2013-11-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Crago, R. D.

    2011-12-01

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

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

    Microsoft Academic Search

    Wilfried Brutsaert

    2006-01-01

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

  4. Prevention against Oxidation of Mn Evaporant during Reactive Evaporation Process

    Microsoft Academic Search

    Masaaki Isai; Hiroshi Fujiyasu

    2001-01-01

    Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, during which its deposition rate deteriorates with increasing deposition run. So it is difficult to maintain the stoichiometry of films from run to run. To prevent deteriorations, a quartz ampoule has been

  5. PAN Pesticide Database

    NSDL National Science Digital Library

    0000-00-00

    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.

  6. Reservoir evaporation in Texas, USA

    NASA Astrophysics Data System (ADS)

    Wurbs, Ralph A.; Ayala, Rolando A.

    2014-03-01

    The role of reservoir surface evaporation in river/reservoir water budgets and water management is explored using a modeling system that combines historical natural hydrology with current conditions of water resources development and management. The long-term mean evaporation from the 3415 reservoirs in the Texas water rights permit system is estimated to be 7.53 billion m3/year, which is equivalent to 61% of total agricultural or 126% of total municipal water use in the state during the year 2010. Evaporation varies with the hydrologic conditions governing reservoir surface areas and evaporation rates. Annual statewide total evaporation volumes associated with exceedance probabilities of 75%, 50%, and 25% are 7.07, 7.47, and 7.95 billion m3/year, respectively. Impacts of evaporation are greatest during extended severe droughts that govern water supply capabilities.

  7. Carrier Gas Dependent Evaporation Energy of GaN Estimated from Spiral Growth Rates in Selective-Area Metalorganic Vapor Phase Epitaxy

    NASA Astrophysics Data System (ADS)

    Akasaka, Tetsuya; Kobayashi, Yasuyuki; Kasu, Makoto; Yamamoto, Hideki

    2013-10-01

    GaN was grown in spiral growth mode by metalorganic vapor phase epitaxy in selective areas having screw-type dislocations. Relationships between the growth rate and supersaturation provide a novel way to estimate the evaporation energy of GaN, which turns out to be carrier gas dependent: 4.3±0.9 eV for N2 and 2.1±0.4 eV for H2. The latter is significantly smaller, probably due to enhanced etching by H2. Suppression of excessive nucleation by etching in H2 may be responsible for the formation of step-free GaN surfaces at low temperatures in selective areas free from screw-type dislocations.

  8. New findings about the complementary relationship-based evaporation estimation methods

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef; Jozsa, Janos

    2008-06-01

    SummaryA novel approach has been found to estimate the equilibrium surface temperature ( Te) of wet environment evaporation ( Ew) on a daily basis. Employing this temperature in the Priestley-Taylor equation as well as in the calculation of the slope of the saturation vapor pressure curve with pan measurements improved the accuracy of long-term mean evaporation ( E) estimation of the Advection-Aridity (AA) model when validated by Morton's approach. Complementarity of the potential evaporation ( Ep) and E terms was considered both on a daily and a monthly basis with the involved terms always calculated daily from 30 yr of hourly meteorological measurements of the 1961-1990 period at 210 SAMSON stations across the contiguous US. The followings were found: (a) only the original Rome wind function of Penman yields a truly symmetric Complementary Relationship between E and Ep which makes the so-obtained Ep estimates true potential evaporation values; (b) the symmetric version of the modified AA model requires no additional parameters to be optimized; (c) for a long-term mean value of evaporation the modified AA model becomes on a par with Morton's approach not only in practical applicability but also in its improved accuracy, especially in arid environments with possible strong convection; (d) the latter two models yielded long-term mean annual evaporation estimates with an R2 of 0.95 for the 210 stations, which is all the more remarkable since they employ very different approaches for their Ep calculations; (e) with identical apparent Ep values the two models yielded practically identical long-term mean annual evaporation rates; (f) with the proper choice of the wind function to estimate apparent Ep the long-term mean annual E estimates of the modified AA model are still very close ( R2 = 0.93) to those of the Morton approach.

  9. Electronic pan/tilt/zoom camera system

    NASA Astrophysics Data System (ADS)

    Zimmermann, Steven D.; Martin, H. Lee

    1993-02-01

    A camera system for omnidirectional image viewing applications that provides pan, tilt, zoom, and rotational orientation within a hemispherical field-of-view utilizing no moving parts has been developed. The imaging device is based on the effect that the image from a fisheye lens, which produces a circular image of an entire hemispherical field-of-view, can be mathematically corrected using high speed electronic circuitry. More specifically, an incoming fisheye image from an 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 field-of-view 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-rotate 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. The device can be used for may applications where a conventional mechanical pan-and-tilt orientation mechanism might be considered including inspection, monitoring, surveillance, and target acquisition. Omniview is ideal for multiple target acquisition and image stabilization in military applications due to its multiple image handling and fast response capabilities.

  10. 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)

    Hsu, Jin-Cherng; Chiang, Yueh-Sheng; Ma, Yu-Sheng

    2013-03-01

    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.

  11. Evaporation of forsterite in H 2 gas

    Microsoft Academic Search

    Hiroko Nagahara; Kazuhito Ozawa

    1996-01-01

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

  12. The rate of water vapor evaporation from ice substrates in the presence of HCl and HBr: implications for the lifetime of atmospheric ice particles

    NASA Astrophysics Data System (ADS)

    Delval, C.; Fluckiger, B.; Rossi, M. J.

    2003-08-01

    Using a multidiagnostic approach the rate Rev [ molec cm-3 s-1] or flux Jev [ molec cm-2 s-1] of evaporation of H2O and its corresponding rate constant for condensation, kcond [s-1 ], on a 1 µm thick ice film have been studied in the temperature range 190 to 240 K as well as in the presence of small amounts of HCl and HBr that left the vapor pressure of H2O on ice unchanged. The resulting Arrhenius expressions for pure ice are Jev = 1.6 · 10 28 ± 1 · exp (- 10.3 ± 1.2/ RT) [ molec cm-2 s-1] , kcond = 1.7 · 10 - 2 ± 1 · exp (+ 1.6 ± 1.5/ RT ) [s -1], in the presence of a HCl mole fraction in the range 3.2 · 10 - 5 - 6.4 · 10 - 3 : Jev = 6.4 · 10 26 ± 1 · exp (- 9.7 ± 1.2/ RT) [ molec cm-2 s-1] , kcond = 2.8 · 10 - 2 ± 1 · exp ( + 1.5 ± 1.6 /RT) [s -1], and a HBr mole fraction smaller than 6.4 · 10 - 3 : Jev = 7.4 · 10 25 ± 1 · exp ( - 9.1 ± 1.2 /RT) [ molec cm-2 s-1] , kcond = 7.1 · 10 - 5 ± 1 · exp (+ 2.6 ± 1.5/ RT) [s -1]. The small negative activation energy for H2O condensation on ice points to a precursor mechanism. The corresponding enthalpy of sublimation is DHsubl = Eev - Econd = 11.9 ± 2.7 kcal mol-1 , DHsubl = 11.2 ± 2.8 kcal mol-1, and DHsubl = 11.7 ± 2.8 kcal mol-1 whose values are identical within experimental uncertainty to the accepted literature value of 12.3 kcal mol-1 . Interferometric data at 633 nm and FTIR absorption spectra in transmission support the kinetic results. The data are consistent with a significant lifetime enhancement for HCl- and HBr-contaminated ice particles by a factor of 3-6 and 10-20, respectively, for submonolayer coverages of HX once the fraction of the ice not contaminated by HX has evaporated.

  13. Electrically controllable artificial PAN muscles

    Microsoft Academic Search

    Karim Salehpoor; Mohsen Shahinpoor; Mehran Mojarrad

    1996-01-01

    Artificial muscles made with polyacrylonitrile (PAN) fibers are traditionally activated in electrolytic solution by changing the pH of the solution by the addition of acids and\\/or bases. This usually consumes a considerable amount of weak acids or bases. Furthermore, the synthetic muscle (PAN) itself has to be impregnated with an acid or a base and must have an appropriate enclosure

  14. Dynamic analysis of evaporator characteristics

    Microsoft Academic Search

    Jae-Dol Kim; Jung-In Yoon; Hag-Geun Ku

    1997-01-01

    An analysis of the dynamic characteristics in an evaporator was numerically performed for control and design of the refrigeration\\u000a and air conditioning systems. The important factors, such as refrigerant flow rate, inlet enthalpy, inlet air velocity and\\u000a air temperature, are incorporated with this analysis. An evaporator is modeled for the dynamic characteristics analysis separated\\u000a into three regions which are the

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  16. A comparison between direct and pan-derived measurements of the isotopic composition of atmospheric

    E-print Network

    Evans, Jason

    , transpiration and surface-waters. However, obtaining extensive and ongoing time series data of the isotopic period such as the relative humidity of air and the air and pan temperatures. Inverting the model to use the isotopic composition of evaporated and transpired waters. It will vary with the origin of the moisture

  17. Flexible microprocessor-based evaporation controller

    Microsoft Academic Search

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

    2004-01-01

    Electron beam evaporation sources require two power supplies, one each for the filament current and the electron acceleration. To obtain a stable deposition rate, the emission current between filament and target must remain constant. During film deposition, slight geometry changes in the evaporator cause significant rate variations, making constant readjustment of the emission current necessary. While in commercial solutions, analog

  18. The rate of water vapor evaporation from ice substrates in the presence of HCl and HBr: Implications for the lifetime of atmospheric ice particles

    NASA Astrophysics Data System (ADS)

    Delval, C.; Fluckiger, B.; Rossi, M. J.

    2003-05-01

    Using a multidiagnostic approach the rate Rev or flux Jevof evaporation of H2O and its condensation, kcond, on a 1mm thick ice film have been studied in the temperature range 190 to 240 K as well as in the presence of small amounts of HCl and HBr that left the vapor pressure of H2O on ice unchanged. The resulting Arrhenius expressions with RT in kcal mol-1 for pure ice are Jev=1.6×1028+/-1·exp({-10.3+-1.2}/{RT}) [molec cm-2 s-1], kcond=1.7×10-2+1×exp({+1.6+-1.5}/{RT}) [s-1], in the presence of an HCl mole fraction in the range 3.2×10-5-6.4×10-3: Jev=6.4×1026+/-1×exp({-9.7+/-1.2}/{RT}) [molec cm-2 s-1], kcond=2.8×10-2+/-1×exp({+1.5+/-1.6}/{RT}) [s-1], and an HBr mole fraction smaller than 6.4×10-3:Jev=7.4×1025+/-1×exp({-9.1+/-1.2}/{RT}) [molec cm-2 s-1], kcond=7.1×10-5+-1×exp({+2.6+/-1.5}/{RT}) [s-1]}. The small negative activation energy for H2O condensation on ice points to a precursor mechanism. The corresponding enthalpy of sublimation is DHsubl=Eev-Econd=11.9+/-2.7 kcal mol-1, DHsubl=11.2+/-2.8 kcal mol-1, and DHsubl=11.7+/-2.8 kcal mol-1 whose values are identical within experimental uncertainty to the accepted literature value of 12.3 kcal mol-1. Interferometric data at 633 nm and FTIR absorption spectra in transmission support the kinetic results. The data are consistent with a significant lifetime enhancement for HCl- and HBr-contaminated ice particles by a factor of 3-6 and 10-20, respectively, for submonolayer coverages of HX.

  19. 78 FR 23101 - Pan American Day and Pan American Week, 2013

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-17

    ...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...

  20. Nanofluid Drop Evaporation: Experiment, Theory, and Modeling

    NASA Astrophysics Data System (ADS)

    Gerken, William James

    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.

  1. The Pan-STARRS1 medium-deep survey: The role of galaxy group environment in the star formation rate versus stellar mass relation and quiescent fraction out to z ? 0.8

    SciTech Connect

    Lin, Lihwai; Chen, Chin-Wei; Coupon, Jean; Hsieh, Bau-Ching [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 106, Taiwan, R.O.C. (China); Jian, Hung-Yu [Department of Physics, National Taiwan University, Taipei 106, Taiwan, R.O.C. (China); Foucaud, Sebastien [Department of Earth Sciences, National Taiwan Normal University, N°88, Tingzhou Road, Sec. 4, Taipei 11677, Taiwan, R.O.C. (China); Norberg, Peder; Bower, R. G.; Cole, Shaun; Arnalte-Mur, Pablo; Draper, P. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Heinis, Sebastien [Department of Astronomy, University of Maryland, MD 20742 (United States); Phleps, Stefanie [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, D-85748 Garching (Germany); Chen, Wen-Ping [Graduate Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan, R.O.C. (China); Lee, Chien-Hsiu [University Observatory Munich, Scheinerstrasse 1, D-81679 Munich (Germany); Burgett, William; Chambers, K. C.; Denneau, L.; Flewelling, H.; Hodapp, K. W., E-mail: lihwailin@asiaa.sinica.edu.tw [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); and others

    2014-02-10

    Using a large optically selected sample of field and group galaxies drawn from the Pan-STARRS1 Medium-Deep Survey (PS1/MDS), we present a detailed analysis of the specific star formation rate (SSFR)—stellar mass (M {sub *}) relation, as well as the quiescent fraction versus M {sub *} relation in different environments. While both the SSFR and the quiescent fraction depend strongly on stellar mass, the environment also plays an important role. Using this large galaxy sample, we confirm that the fraction of quiescent galaxies is strongly dependent on environment at a fixed stellar mass, but that the amplitude and the slope of the star-forming sequence is similar between the field and groups: in other words, the SSFR-density relation at a fixed stellar mass is primarily driven by the change in the star-forming and quiescent fractions between different environments rather than a global suppression in the star formation rate for the star-forming population. However, when we restrict our sample to the cluster-scale environments (M > 10{sup 14} M {sub ?}), we find a global reduction in the SSFR of the star-forming sequence of 17% at 4? confidence as opposed to its field counterpart. After removing the stellar mass dependence of the quiescent fraction seen in field galaxies, the excess in the quiescent fraction due to the environment quenching in groups and clusters is found to increase with stellar mass, although deeper and larger data from the full PS1/MDS will be required to draw firm conclusions. We argue that these results are in favor of galaxy mergers to be the primary environment quenching mechanism operating in galaxy groups whereas strangulation is able to reproduce the observed trend in the environment quenching efficiency and stellar mass relation seen in clusters. Our results also suggest that the relative importance between mass quenching and environment quenching depends on stellar mass—the mass quenching plays a dominant role in producing quiescent galaxies for more massive galaxies, while less massive galaxies are quenched mostly through the environmental effect, with the transition mass around 1-2 × 10{sup 10} M {sub ?} in the group/cluster environment.

  2. Changes in the atmospheric evaporative demand in Mexico

    NASA Astrophysics Data System (ADS)

    Agustin Brena-Naranjo, Jose; Pedrozo-Acuña, Adrian; Laverde-Barajas, Miguel

    2015-04-01

    An important driver of the hydrological cycle is the atmospheric evaporative demand (AED). Previous studies using measurements of evaporation in pans have found evidence that AED has been declining over the second half of the 20th century. Such trends have been mostly attributed to a global decline in near surface wind speed (mainly driven by changes in land cover such as the terrestrial surface roughness) whereas other variables controlling AED such as the vapor pressure deficit, solar radiation and air temperature having a more limited role (such changes are driven by long-term climatic variations). The objective of this work is to assess the temporal and spatial observed changes in pan evaporation in 151 meteorological stations located across Mexico for the period 1961-2010. The stations were located on a climatic gradient, with aridity indexes ranging between 0.3 and 10. The radiative and aerodynamic controls attributed to the observed trends are analyzed with outputs by the Noah model from the Global Land Data Assimilation System (GLDAS). The results show a consistent decline in annual pan evaporation between 1961 and 1992 whereas the trend was reverted from 1992 until 2010. Statistically significant negative changes using the non-parametric Mann-Kendall test were found in 43% of the stations for the 1961-1992 and 20% for 1992-2010, respectively. Among the climatological variables extracted from GLDAS, it was the annual wind speed that gave the highest statistical correlation. This work agrees with previous studies in other regions of the world suggesting that pan evaporation has been on average declining until 1990 followed by a slightly positive trend during the last twenty years. Finally, we show that the magnitude of change in those regions dominated by wind and those dominated by radiative processes are strongly different.

  3. The Role of Hysteresis in Reducing Evaporation from Soils in Contact with a Water Table

    Microsoft Academic Search

    Richard A. Schleusener; A. T. Corey

    1959-01-01

    Evaporation studies were conducted on three soil types in contact with a water table. For conditions of high evaporativity or increased depth to the water table, it was found that evaporation from the soils was not always in proportion to the rate of evaporation from a free-water surface. Under some conditions there was an inverse relation between evaporation from the

  4. 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)

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

    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.

  5. Evaporation of petroleum products from contaminated soils

    Microsoft Academic Search

    Seon-Hong Kang; Charles S. Oulman

    1996-01-01

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

  6. A search for fast optical transients in the Pan-STARRS1 medium-deep survey: M-dwarf flares, asteroids, limits on extragalactic rates, and implications for LSST

    SciTech Connect

    Berger, E.; Leibler, C. N.; Chornock, R.; Foley, R. J.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Tonry, J. L. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Metcalfe, N. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Stubbs, C. W. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States)

    2013-12-10

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

  7. Preciptation, Evaporation, and Transpiration Activity

    NSDL National Science Digital Library

    Amy Townsend-Small

    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.

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

    PubMed

    Hoffman; Walsberg

    1999-01-01

    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

  9. PAN-on-Demand: Leveraging multiple radios to build self-organizing, energy-efficient PANs

    E-print Network

    Flinn, Jason

    PAN-on-Demand: Leveraging multiple radios to build self-organizing, energy-efficient PANs Manish Arbor, MI jflinn@eecs.umich.edu ABSTRACT We present PAN-on-Demand, a self-organizing wireless personal- area network (PAN) that balances performance and energy con- cerns by scaling the structure

  10. An electronic pan/tilt/zoom camera system

    NASA Technical Reports Server (NTRS)

    Zimmermann, Steve; Martin, H. L.

    1992-01-01

    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.

  11. Salt stains from evaporating droplets

    PubMed Central

    Shahidzadeh, Noushine; Schut, Marthe F. L.; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  12. Salt stains from evaporating droplets.

    PubMed

    Shahidzadeh, Noushine; Schut, Marthe F L; Desarnaud, Julie; Prat, Marc; Bonn, Daniel

    2015-01-01

    The study of the behavior of sessile droplets on solid substrates is not only associated with common everyday phenomena, such as the coffee stain effect, limescale deposits on our bathroom walls , but also very important in many applications such as purification of pharmaceuticals, de-icing of airplanes, inkjet printing and coating applications. In many of these processes, a phase change happens within the drop because of solvent evaporation, temperature changes or chemical reactions, which consequently lead to liquid to solid transitions in the droplets. Here we show that crystallization patterns of evaporating of water drops containing dissolved salts are different from the stains reported for evaporating colloidal suspensions. This happens because during the solvent evaporation, the salts crystallize and grow during the drying. Our results show that the patterns of the resulting salt crystal stains are mainly governed by wetting properties of the emerging crystal as well as the pathway of nucleation and growth, and are independent of the evaporation rate and thermal conductivity of the substrates. PMID:26012481

  13. Evaporator Cleaning Studies

    SciTech Connect

    Wilmarth, W.R.

    1999-04-15

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

  14. Pan-Private Streaming Algorithms Cynthia Dwork

    E-print Network

    Pan-Private Streaming Algorithms Cynthia Dwork Moni Naor Toniann Pitassi Guy N. Rothblum§ Sergey they were collected. To support the data curators, we initiate a study of pan-private algorithms; roughly the privacy of the sampled individuals. We therefore initiate a study of pan-private algorithms; roughly

  15. 5, 56695685, 2005 Low temperature PAN

    E-print Network

    Paris-Sud XI, Université de

    ACPD 5, 5669­5685, 2005 Low temperature PAN cross-sections G. Allen et al. Title Page Abstract temperature mid-infrared cross-sections for peroxyacetyl nitrate (PAN) vapour G. Allen 1 , J. J. Remedios 1 License. 5669 #12;ACPD 5, 5669­5685, 2005 Low temperature PAN cross-sections G. Allen et al. Title Page

  16. 7, 56175645, 2007 Seasonality of PAN in

    E-print Network

    Boyer, Edmond

    ACPD 7, 5617­5645, 2007 Seasonality of PAN in coastal antarctica G. P. Mills et al. Title Page Chemistry and Physics Discussions Seasonal variation of peroxyacetylnitrate (PAN) in coastal Antarctica measured with a new instrument for the detection of sub-part per trillion mixing ratios of PAN G. P. Mills1

  17. Evaporative cooling in insects

    Microsoft Academic Search

    Henry D. Prange

    1996-01-01

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

  18. Modeling monthly evaporation using two different neural computing techniques

    Microsoft Academic Search

    Özgür Ki?i

    2009-01-01

    Two different artificial neural network (ANN) techniques, multi-layer perceptrons (MLP) and radial basis neural networks (RBNN),\\u000a are employed in the estimation of monthly pan evaporation. The monthly climatic data, air temperature, solar radiation, wind\\u000a speed, pressure and humidity, of three stations operated by the U.S. Environmental Protection Agency in California are used\\u000a as inputs to the ANN models to estimate

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

    Microsoft Academic Search

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

    2007-01-01

    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

  20. Electrically controllable artificial PAN muscles

    NASA Astrophysics Data System (ADS)

    Salehpoor, Karim; Shahinpoor, Mohsen; Mojarrad, Mehran

    1996-02-01

    Artificial muscles made with polyacrylonitrile (PAN) fibers are traditionally activated in electrolytic solution by changing the pH of the solution by the addition of acids and/or bases. This usually consumes a considerable amount of weak acids or bases. Furthermore, the synthetic muscle (PAN) itself has to be impregnated with an acid or a base and must have an appropriate enclosure or provision for waste collection after actuation. This work introduces a method by which the PAN muscle may be elongated or contracted in an electric field. We believe this is the first time that this has been achieved with PAN fibers as artificial muscles. In this new development the PAN muscle is first put in close contact with one of the two platinum wires (electrodes) immersed in an aqueous solution of sodium chloride. Applying an electric voltage between the two wires changes the local acidity of the solution in the regions close to the platinum wires. This is because of the ionization of sodium chloride molecules and the accumulation of Na+ and Cl- ions at the negative and positive electrode sites, respectively. This ion accumulation, in turn, is accompanied by a sharp increase and decrease of the local acidity in regions close to either of the platinum wires, respectively. An artificial muscle, in close contact with the platinum wire, because of the change in the local acidity will contract or expand depending on the polarity of the electric field. This scheme allows the experimenter to use a fixed flexible container of an electrolytic solution whose local pH can be modulated by an imposed electric field while the produced ions are basically trapped to stay in the neighborhood of a given electrode. This method of artificial muscle activation has several advantages. First, the need to use a large quantity of acidic or alkaline solutions is eliminated. Second, the use of a compact PAN muscular system is facilitated for applications in active musculoskeletal structures. Third, the PAN muscles become electrically controllable and therefore the use of such artificial muscles in robotic structures and applications becomes more feasible. A muscle is designed such that it is exposed to either Na+ or Cl- ions effectively. Muscle contraction or expansion characteristics under the effect of the applied electric field are discussed.

  1. On the evaporation of ammonium sulfate solution

    SciTech Connect

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

    2009-07-16

    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.

  2. Evaporator film coefficients of grooved heat pipes

    NASA Technical Reports Server (NTRS)

    Kamotani, Y.

    1978-01-01

    The heat transfer rate in the meniscus attachment region of a grooved heat pipe evaporator is studied theoretically. The analysis shows that the evaporation takes place mainly in the region where the liquid changes its shape sharply. However, comparisons with available heat transfer data indicate that the heat transfer rate in the meniscus varying region is substantially reduced probably due to groove wall surface roughness.

  3. Measurements of Evaporation Kinetics of Aqueous Aerosols

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  4. Vapor compression evaporator concentrates, recovers alcohol

    SciTech Connect

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

    1982-11-01

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

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

    Microsoft Academic Search

    Masaaki Isai; Takeyoshi Shimada; Takaaki Matsui; Hiroshi Fujiyasu

    2001-01-01

    Manganese oxide films for lithium secondary batteries were prepared using a reactive evaporation method. The Mn metal in the crucible suffers severe oxidation during the reactive evaporation process, which deteriorates it's deposition rate with increasing deposition run. It is also difficult to maintain the stoichiometry of films from run to run. This paper shows a new technique which keeps off

  6. Evaporation from the free water surface of a flooded forest

    NASA Astrophysics Data System (ADS)

    Newman, A.; Keim, R.; Hiscox, A.

    2011-12-01

    Controls on evaporation rates from the free water surface of flooded forests have received little attention despite being an important component of the water balance in wetlands. In flooded forests, the tree canopy reduces solar radiation and turbulent exchange, so evaporation rates are lower than from an open water body. We measured evaporation from the free water surface in a flooded cypress/tupelo forest in southern Louisiana, USA, using both Bowen-ratio energy balance and eddy covariance methods. We compare results, which to our knowledge comprise the first experimental data set of evaporation rates in a flooded forest, to rates predicted by a simple empirical model.

  7. Pan American Health Organization (PAHO)

    NSDL National Science Digital Library

    1997-01-01

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

  8. Evaporation from flowing channels

    SciTech Connect

    Fulford, J.M.; Sturm, T.W.

    1984-03-01

    Stability-dependent and Dalton-type mass transfer formulas are determined from experimental evaporation data in ambient and heated channels and are shown to have similar performance in prediction of evaporation. The formulas developed are compared with those proposed by other investigators for lakes and flowing channels. The evaporation data were obtained from a heat-budget analysis of two large outdoor channels, one of which received ambient-temperature water from an adjacent reservoir while the other received an artificially-heated discharge. Daily evaporation was calculated from bihourly values of water temperature and hourly values of meteorological variables for a 63-day study period in the summer. The evaporation data were then used to derive mass transfer evaporation formulas for heated and ambient flowing channels.

  9. Laboratory prototype flash evaporator

    NASA Technical Reports Server (NTRS)

    Gaddis, J. L.

    1972-01-01

    A laboratory prototype flash evaporator that is being developed as a candidate for the space shuttle environmental control system expendable heat sink is described. The single evaporator configuration uses water as an evaporant to accommodate reentry and on-orbit peak heat loads, and Freon 22 for terrestrial flight phases below 120,000 feet altitude. The design features, fabrication techniques used for the prototype unit, redundancy considerations, and the fluid temperature control arrangement are reported in detail. The results of an extensive test program to determine the evaporator operational characteristics under a wide variety of conditions are presented.

  10. Helicity transfer in rotary evaporator flow

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  11. Pan European Socially Responsible Investment Policy

    E-print Network

    Glasgow, University of

    (SRI) in the Pan European Market. Schroders believes that companies have the ability to enhance responsibility and corporate governance activities and their economic impact, providing consistent information

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

    SciTech Connect

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

    1984-01-01

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

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

    EPA Science Inventory

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

  14. Coupling of evaporative fluxes from drying porous surfaces with air boundary layer: Characteristics of evaporation from discrete pores

    NASA Astrophysics Data System (ADS)

    Shahraeeni, Ebrahim; Lehmann, Peter; Or, Dani

    2012-09-01

    Prediction of drying rates from porous media remains a challenge due to complex interactions between ambient conditions and porous medium properties. Evaporation from a gradually drying porous surface across air boundary layer exhibits nonlinear behavior due to enhanced diffusive fluxes from increasingly isolated active pores. These nonlinear interactions were quantified by modeling evaporation from surfaces composed of individual pores considering surface water content dynamics and internal transport within the medium. Wind tunnel experiments show that in contrast with nearly constant evaporation rates obtained at low atmospheric demand (typically <5 mm/d), evaporation fluxes under high atmospheric demand (high air velocities) exhibit a continuous decrease with surface drying even in the absence of internal capillary flow limitations. The isolated pore evaporation model captures surface drying dynamics for a range of atmospheric demands associated with air velocity and boundary layer thickness. As a surface dries under low atmospheric demand (low air speed, thick boundary layer), the remaining active pores become gradually isolated with a conforming vapor concentration field becoming increasingly three-dimensional thereby enhancing evaporative flux per pore. Such enhancement may fully compensate for reduced evaporative surface area leading to observed constant evaporation rate under low demand. For high evaporative demand, limitations to vapor field configuration within thin boundary layer limit flux compensation efficiency and leads to decreasing evaporative flux with surface drying irrespective of internal supply capacity. The model provides new insights into the intrinsic links between surface properties and atmospheric conditions in determining a range of evaporative dynamics for similar surface wetness conditions.

  15. Evaporation, Boiling and Bubbles

    ERIC Educational Resources Information Center

    Goodwin, Alan

    2012-01-01

    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…

  16. Modelling evaporation from reservoirs

    Microsoft Academic Search

    B. HENDERSON-SELLERS

    It is shown that a numerical model for predicting the depth time variation of water temperature in a fresh water lake or reservoir can be used also for prediction of water losses due to evaporation. The seasonal change in peak evaporation from summer (in small lakes) to winter (in large lakes) is satisfactorily simulated.

  17. Does (Multi-)Touch Aid Users' Spatial Memory and Navigation in `Panning' and in `Zooming & Panning' UIs?

    E-print Network

    Reiterer, Harald

    Does (Multi-)Touch Aid Users' Spatial Memory and Navigation in `Panning' and in `Zooming & Panning to master a system than we typically believe ­ especially for spatial panning or zooming & panning user' spatial memory and navigation performance for such UIs. We observed increased performances for panning UIs

  18. 1. Pan W et al. Control and Decision conference 2012, submitted. 2. Pan W et al. Physical Review Letters, submitted.

    E-print Network

    Chaudhuri, Surajit

    References 1. Pan W et al. Control and Decision conference 2012, submitted. 2. Pan W et al. Physical Review Letters, submitted. Contact details Wei Pan, w.pan11@imperial.ac.uk. Acknowledgements parameters can be reconstructed. Method Wei Pan1 , Ye Yuan1,2, Guy-Bart Stan1 1. Centre for Synthetic Biology

  19. 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

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

    1993-03-01

    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

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

    Microsoft Academic Search

    Concepción Collar; Clara Bollaín

    2005-01-01

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

  1. Evaporative Cooling of Trapped Atoms

    Microsoft Academic Search

    Wolfgang Ketterle; N. J. Van Druten

    1996-01-01

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

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

    PubMed

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

    2015-02-01

    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

  3. Evaporation, Condensation, and Precipitation

    NSDL National Science Digital Library

    Miss Brown

    2009-10-21

    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 ...

  4. Sheet Membrane Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  5. Mixed feed evaporator

    DOEpatents

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

    1982-01-01

    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.

  6. Evaporation of germanium nitride

    Microsoft Academic Search

    É. A. Ryklis; A. S. Bolgar; M. D. Lyutaya; V. V. Fesenko

    1968-01-01

    1.A study was made, using Knudsen's effusion method, of the evaporation of germanium nitride over the temperature range 923–963°K. It is shown that, on evaporation, this compound dissociates into solid germanium and nitrogen.2.The vapor pressure above germanium nitride depends on test duration and on the surface area of the effusion orifice.3.The equilibrium values of vapor pressure above Ge3N4 and the

  7. Evaporated Cermet Materials

    Microsoft Academic Search

    G. Riddle

    1967-01-01

    Both resistive and insulating cermets were obtained from experiments on co-evaporated materials. Stable resistivities in the 1000 micro-ohm-centimeter range were obtained from mixtures of germanium and chromium, and from a reaction product of aluminum and alumina. Glassy dielectric films were obtained from reaction products of aluminum and alumina, and from aluminum and silicon monoxide. The factors that control these co-evaporation

  8. Nonlinear effects of salt concentrations on evaporation from porous media

    NASA Astrophysics Data System (ADS)

    Norouzi Rad, Mansoureh; Shokri, Nima

    2012-02-01

    Evaporation from porous media saturated with salt solution is influenced by the interactions among the transport properties of porous media, thermodynamics of the evaporating solution and environmental conditions. To study the effects of salt concentrations on the evaporation dynamics, we conducted a series of evaporation experiments under constant atmospheric conditions using columns packed with sand particles saturated with various NaCl solutions differing in concentrations. Results show that the evaporation rate decreases as NaCl concentration increases only up to a certain level. When exceeding this level, any further increase of NaCl concentration results in higher evaporation rates which is described theoretically using the thermodynamics of the solution. Results also reveal a nonlinear relation between NaCl concentrations and onset of efflorescence which is described by the numerical solution of the classical convection-diffusion equation. Moreover, we found a strong correlation between the growth dynamics of precipitated salt at the surface and the evaporation rate such that the maximum rate of surface coverage by salt coincide with the end of stage-1 evaporation. This potentially offers a new method to nondestructively study the evaporation process from saline porous media.

  9. Combined Evaporation and Salt Precipitation in Porous Media

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  10. Raman Thermometry Measurements of Free Evaporation from LiquidWater Droplets

    SciTech Connect

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

    2006-05-22

    Recent theoretical and experimental studies of evaporation have suggested that on average, molecules in the higher-energy tail of the Boltzmann distribution are more readily transferred into the vapor during evaporation. To test these conclusions, the evaporative cooling rates of a droplet train of liquid water injected into vacuum have been studied via Raman thermometry. The resulting cooling rates are fit to an evaporative cooling model based on Knudsen's maximum rate of evaporation, in which we explicitly account for surface cooling. We have determined that the value of the evaporation coefficient ({gamma}{sub e}) of liquid water is 0.62 {+-} 0.09, confirming that a rate-limiting barrier impedes the evaporation rate. Such insight will facilitate the formulation of a microscopic mechanism for the evaporation of liquid water.

  11. Bioanalysis young investigator: Pan Deng.

    PubMed

    Deng, Pan

    2012-05-01

    I would like to nominate Pan Deng for the Bioanalysis Young Investigator Award 2012. Her research projects include developing LC-MS/MS methods for the quantification of small and large molecules to support drug pharmacokinetic studies. During her PhD training in my laboratory, she has gained much experience in developing sensitive LC-MS/MS methods for the measurement of various compounds, especially polar analytes, and published several research and review papers. As part of her PhD project, she also investigated the metabolism of drugs utilizing UPLC-Q/TOF MS. Her efforts in studying drug metabolism study have led to the finding of new metabolites, and unveiling the metabolic pathways of several new drug candidates. She is currently expanding her research into the area of drug toxicity. Hopefully this Young Investigator Award will encourage Deng to have greater achievements. PMID:22612679

  12. Panning for Gold and Magnetite

    NSDL National Science Digital Library

    Eleanora Robbins

    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.

  13. Ionic strength-sensitive pullulan acetate nanoparticles (PAN) for intratumoral administration of radioisotope: ionic strength-dependent aggregation behavior and (99m)Technetium retention property.

    PubMed

    Park, Keun-Hong; Song, Ho-Chun; Na, Kun; Bom, Hee-Seung; Lee, Kwang Hee; Kim, Sungwon; Kang, Dongmin; Lee, Don Haeng

    2007-09-01

    In order to design an effective intratumoral radioisotope carrier, a self-assembled nanoparticle evidencing ionic strength (IS)-sensitivity from a polysaccharide derivative (pullulan acetate nanoparticle (PAN)) was prepared via dialysis. The PAN had a spherical shape in a range of size of 50-130 nm and a low critical aggregation concentration (CAC) (<8 microg/mL). With increases in the IS of the dialysis media (IS(dia)), the CAC of PAN was reduced gradually and the rigidity of the hydrophobic core in PAN was increased. This suggests that the property of PAN was altered more hydrophobically at high IS values. The stabilities of PANs prepared from various IS(dia) were also monitored with changes in the turbidity and particle size in different IS solutions. In the case of PAN prepared at an IS(dia)=0.0, the turbidity was dramatically reduced with increasing IS due to the facilitation of aggregation between the particles, whereas in the other cases, these changes were negligible. This finding indicates that PAN prepared in distilled water (IS=0.0) can be readily injected as the consequence of its nano-size, and accumulates quickly, then remains in the tumor site for a considerable period (IS=0.15). In order to closely estimate the potential of PAN as a radioisotope carrier, the radioisotope labeling efficiency of PAN with no chelating agents was evaluated. PAN evidenced a high degree of (99m)Technetium ((99m)Tc) labeling efficiency (approximately 98%). The percentage retention rate (%RR) of the (99m)Tc-labeled PAN was significantly longer than that of the free (99m)Tc (p<0.05), due largely to PAN's IS-sensitivity. In conclusion, PAN may constitute a new approach to the achievement of maximal radioisotope efficiency with regard to intratumoral administration. PMID:17532195

  14. The continuous similarity model of bulk soil-water evaporation

    NASA Technical Reports Server (NTRS)

    Clapp, R. B.

    1983-01-01

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

  15. Thermocapillary transport of energy during water evaporation.

    PubMed

    Duan, Fei; Badam, V K; Durst, F; Ward, C A

    2005-11-01

    When evaporation occurs at a spherical water-vapor interface maintained at the circular mouth of a small funnel, studies of the energy transport have indicated that thermal conduction alone does not provide enough energy to evaporate the liquid at the observed rate. If the Gibbs model of the interface is adopted and the "surface-thermal capacity" is assigned a value of 30.6+/-0.8 kJ/(m2 K), then for evaporation experiments with the interfacial temperature in the range -10 degrees C< or =TLV< or =3.5 degrees C and Marangoni number (Ma) in the range 100evaporated at cylindrical interfaces that were, on average, 4.4 times larger in area than that of the spherical interfaces used to measure the surface-thermal capacity initially. It is shown that using the value of the surface-thermal capacity determined at a spherical interface, the energy transported by thermocapillary convection and thermal conduction at a cylindrical interface is sufficient to evaporate the liquid at the observed rate. Knowing the value of the surface-thermal capacity also allows the local evaporation flux to be calculated from the measured temperature profiles in the liquid and vapor phases. The calculated local evaporation flux can then be used with statistical rate theory to calculate the vapor-phase pressure along the interface. The predicted mean vapor-phase pressure is in close agreement with that measured, and the predicted pressure gradient is consistent with that expected when thermocapillary convection is present. PMID:16383741

  16. Evaporative Cooling for Energy Conservation 

    E-print Network

    Meyer, J. R.

    1983-01-01

    be required. Description 1) Reciprocating Air-Cooled chiller supplying coil added to each existing fan. 2) City water coil added to each existing fan. 3) Evaporative cooler added to each existing fan. A. E!.>umate.d CoM B ? Ac..:tw:Le. Co!.>.t. C.... E!.>umate.d Adc:LULolw..t OjOeJta..ti.ng Co!.>.t due. .to ne.w e.qLUjOme.nt Assuming the original fans could be reused at the existing flow rate of 8000 CFM with an 80 F. discharge temperature, 86 tons of cooling would be required. Since budget...

  17. The Upper Tropospheric Budget of PAN

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  18. Evaporation-induced cavitation in nanofluidic channels

    PubMed Central

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

    2012-01-01

    Cavitation, known as the formation of vapor bubbles when liquids are under tension, is of great interest both in condensed matter science as well as in diverse applications such as botany, hydraulic engineering, and medicine. Although widely studied in bulk and microscale-confined liquids, cavitation in the nanoscale is generally believed to be energetically unfavorable and has never been experimentally demonstrated. Here we report evaporation-induced cavitation in water-filled hydrophilic nanochannels under enormous negative pressures up to -7 MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro- and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale. PMID:22343530

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

    Microsoft Academic Search

    Merv F. Fingas

    1998-01-01

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

  20. Comparison of techniques for estimating evaporation from an irrigation water storage

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  1. Pan-Sharpening Using Induction Muhammad Murtaza Khan, Jocelyn Chanussot

    E-print Network

    Condat, Laurent

    Pan-Sharpening Using Induction Muhammad Murtaza Khan, Jocelyn Chanussot and Annick Montanvert GIPSA: laurent.condat@gsf.de Abstract--Pan-sharpening is the process of improving spatial resolution of multi-spectral (MS) satellite images using the spatial details of a high resolution Panchromatic (PAN) image. Pan

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

    E-print Network

    Masci, Frank

    Pan-STARRS Document Control PSDC-002-011-xx UNIVERSITY OF HAWAII AT MANOA Institute for Astrononmy Pan-STARRS Project Management System Addition of Images with Varying Seeing Nick Kaiser Pan, Hawaii 96822 An Equal Opportunity/Affirmative Action Institution #12;Pan-STARRS PSDC-002-011-xx Revision

  3. Structuring of polymer solutions upon solvent evaporation

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

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

    USGS Publications Warehouse

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

    2003-01-01

    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.

  5. Evaporation over fresh and saline water surfaces

    NASA Astrophysics Data System (ADS)

    Abdelrady, Ahmed; Timmermans, Joris; Vekerdy, Zoltan

    2013-04-01

    Evaporation over large water bodies has a crucial role in the global hydrological cycle. Evaporation occurs whenever there is a vapor pressure deficit between a water surface and the atmosphere, and the available energy is sufficient. Salinity affects the density and latent heat of vaporization of the water body, which reflects on the evaporation rate. Different models have been developed to estimate the evaporation process over water surfaces using earth observation data. Most of these models are concerned with the atmospheric parameters. However these models do not take into account the influence of salinity on the evaporation rate; they do not consider the difference in the energy needed for vaporization. For this purpose an energy balance model is required. Several energy balance models that calculate daily evapotranspiration exist, such as the surface energy balance system (SEBS). They estimate the heat fluxes by integration of satellite data and hydro-meteorological field data. SEBS has the advantage that it can be applied over a large scale because it incorporates the physical state of the surface and the aerodynamic resistances in the daily evapotranspiration estimation. Nevertheless this model has not used over water surfaces. The goal of this research is to adapt SEBS to estimate the daily evaporation over fresh and saline water bodies. In particular, 1) water heat flux and roughness of momentum and heat transfer estimation need to be updated, 2) upscaling to daily evaporation needs to be investigated and finally 3) integration of the salinity factor to estimate the evaporation over saline water needs to be performed. Eddy covariance measurements over the Ijsselmeer Lake (The Netherlands) were used to estimate the roughness of momentum and heat transfer at respectively 0.0002 and 0.0001 m. Application of these values over Tana Lake (freshwater), in Ethiopia showed latent heat to be in a good agreement with the measurements, with RMSE of 35.5 Wm-2and rRMSE of 4.7 %. Afterwards the validity of salinity adapted model was tested over different study areas using ECMWF data. It was found that for the original SEBS model and salinity-adapted model over Great Salt Lake, the RMSE were 0.62 and 0.24 mm respectively and the rRMSE 19% and 24%. The evaporation reduction of the Great Salt Lake and the oceans are 27% and 1 %, respectively. In conclusion, SEBS model is adapted to calculate the daily evaporation over fresh water and salt water by integration the salinity factor in the model.

  6. An electronic pan/tilt/zoom camera system

    NASA Technical Reports Server (NTRS)

    Zimmermann, Steve; Martin, H. Lee

    1991-01-01

    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.

  7. How do drops evaporate?

    NASA Astrophysics Data System (ADS)

    Murisic, Nebojsa; Kondic, Lou

    2007-11-01

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

  8. The Pan-STARRS discovery machine

    NASA Astrophysics Data System (ADS)

    Chambers, Kenneth C.

    2014-11-01

    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).

  9. 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)

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

    2012-10-01

    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.

  10. Analytical solution for soil water redistribution during evaporation process.

    PubMed

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

    2013-01-01

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

  11. Atmospheric impacts of evaporative cooling systems

    Microsoft Academic Search

    1976-01-01

    The report summarizes available information on the effects of various power plant cooling systems on the atmosphere. While evaporative cooling systems sharply reduce the biological impacts of thermal discharges in water bodies, they create (at least, for heat-release rates comparable to those of two-unit nuclear generating stations) atmospheric changes. For an isolated site such as required for a nuclear power

  12. EVAPORATIVE WATER LOSS IN SCALELESS SNAKES

    E-print Network

    Bennett, Albert F.

    EVAPORATIVE WATER LOSS IN SCALELESS SNAKES ALBERTF. BENNETT*AND PAULLICHT Department of Zoology, University of California, Berkeley, CA 94720, U.S.A. (Received 19 June 1974) Abstract-1. Rates of water loss. Pulmocutaneous water loss of the scaleless animals was equal to or less than that of the controls at 20, 27

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  14. 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

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

    2006-01-01

    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

  15. Color of Evaporated Milks

    Microsoft Academic Search

    Byron H. Webb; George E. Holm

    1930-01-01

    Agriculture The color of evaporated milk is of considerable commercial im- portance since it is one of the fundamental characteristics by which the consumer judges the product. Some of the various factors concerned in the production of color are recognized in a general qualitative way by the producer. No data, however, are available dealing with the factors concerned in the

  16. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

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

  17. Evaporative cooling of antiprotons to cryogenic temperatures.

    PubMed

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

    2010-07-01

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

  18. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    E-print Network

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

    2010-09-23

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

  19. Evaporative cooling of magnetically trapped atomic molybdenum

    SciTech Connect

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

    2005-03-01

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

  20. Evaporative Cooling of Antiprotons to Cryogenic Temperatures

    SciTech Connect

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

    2010-07-02

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

  1. Seasonal Transpacific Transport of Asian Ozone and PAN Using Aura TES PAN Retrievals

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Worden, J.; Payne, V.; Fischer, E. V.; Walker, T. W.; Jones, D. B. A.; Henze, D. K.

    2014-12-01

    Long range transport of Asian ozone pollution depends on the conversion of surface NOx emissions into Peroxyacyl Nitrate (PAN) and subsequent transpacific transport of PAN in the free-troposphere where it is stable because of cold temperatures. Once PAN subsides into the warmer lower troposphere it is converted back into NOx, which can in turn form ozone. In this presentation we use new PAN retrievals from the Aura TES instrument to characterize the seasonal cycle of free-tropospheric PAN from Asian emissions and its subsequent transport to North America. The GEOS-Chem chemical transport model and its adjoint are used to quantify the intercontinental source attribution of ozone pollution at western United States.

  2. Intensification of evaporation processes using surfactants

    NASA Astrophysics Data System (ADS)

    Sharifullin, V. N.; Sharifullin, A. V.

    2015-06-01

    The effect of a group of low molecular surfactants on the evaporation rate during nucleate boiling of water is investigated. It is found that the vaporization rate and heat flux from the heater increase by 4-8% in an electric boiler with surfactants. The analysis of the process based on the model of the phase contact surface restoration made it possible to formulate the mechanism of the effect of considered surfactants.

  3. 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).

  4. Lake Evaporation: a Model Study

    Microsoft Academic Search

    Jumah Ahmad Amayreh

    1995-01-01

    Reliable evaporation data are an essential requirement in any water and\\/or energy budget studies. This includes operation and management of both urban and agricultural water resources. Evaporation from large, open water surfaces such as lakes and reservoirs may influence many agricultural and irrigation decisions. In this study evaporation from Bear Lake in the states of Idaho and Utah was measured

  5. Characteristic lengths for evaporation suppression from patchy porous surfaces

    NASA Astrophysics Data System (ADS)

    Lehmann, Peter; Or, Dani

    2014-05-01

    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.

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

    PubMed

    Schäfer, Ingmar B; Rode, Michaela; Bonneau, Fabien; Schüssler, Steffen; Conti, Elena

    2014-07-01

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

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

    Microsoft Academic Search

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

    1984-01-01

    The Bureau of Mines investigated energy-efficient methods for recovering potash values from process and waste brines. Laboratory pan evaporation of four chloride brines produced crude salts containing predominantly sylvite, halite, and carnallite. Six sulfate-chloride brines produced crude salts containing primarily schoenite, kainite, leonite, sylvite, carnallite, and halite. Potash grades ranged from 7.2 to 22.2% KâO, and recoveries from 84 to

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

    E-print Network

    Mottram, Nigel

    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

  9. Biology 390 Problem: Evaporative Water Loss and Temp Reg. thanks to Dr. J.F. Anderson,

    E-print Network

    Prestwich, Ken

    by evaporative cooling during one day by a 70 kg mammal whose rate of metabolism is 3,000 Kcal/day. Assume evaporative cooling is the only mode of heat exchange this mammal can use to regulate its body temperature, iBiology 390 Problem: Evaporative Water Loss and Temp Reg. thanks to Dr. J.F. Anderson, Dept Zoology

  10. Biology 390 Problem: Evaporative Water Loss and Temp Reg. thanks to Dr. J.F. Anderson,

    E-print Network

    Prestwich, Ken

    by evaporative cooling during one day by a 70 kg mammal whose rate of metabolism is 3,000 Kcal/day. Assume evaporative cooling is the only mode of heat exchange this mammal can use to regulate its body temperature, i need rely less on evaporative cooling. Provided that they have an effective way to reduce respiratory

  11. ccsd-00005011,version1-30May2005 Evaporative Cooling of a Guided Rubidium Atomic Beam

    E-print Network

    ccsd-00005011,version1-30May2005 Evaporative Cooling of a Guided Rubidium Atomic Beam T. Lahaye, Z an upward slope. The relatively high collision rate (5 s-1 ) allows us to start forced evaporative cooling of the on-axis phase-space density. PACS numbers: 32.80.Pj,03.75.Pp I. INTRODUCTION Evaporative cooling

  12. EVAPORATIVE COOLING AND WATER BALANCE DURING FLIGHT IN BIRDS

    Microsoft Academic Search

    JOSE R. TORRE-BUENO

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

  13. KEPLER PLANETS: A TALE OF EVAPORATION

    SciTech Connect

    Owen, James E. [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Wu, Yanqin, E-mail: jowen@cita.utoronto.ca, E-mail: wu@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

    2013-10-01

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

  14. Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Almlie, Jay C.

    2010-01-01

    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.

  15. Fundamental study of evaporation model in micron pore 

    E-print Network

    Oinuma, Ryoji

    2004-11-15

    ? ........................................................................ 88 4-4 Bottom Curvature and Evaporation Rate per Pore (n=10)............................113 4-5 Bottom Curvature and Evaporation Rate per Pore (n=20)............................113 xiii LIST OF FIGURES FIGURE Page 2-1. Classification... e T P T T Mkm ? ? ? ? ? 5.01 ) 52 1& (2-6) where m is the mass flux, M is the molecular weight, k is Boltzmann?s constant, e? and c? are the evaporation and condensation coefficients, eP is the equilibrium pressure which is given as...

  16. Control of solvent evaporation in hen egg white lysozyme crystallization

    NASA Technical Reports Server (NTRS)

    Wilson, L. J.; Suddath, F. L.

    1992-01-01

    An investigation of the role of solvent evaporation in tetragonal lysozyme crystallization was preformed with a device that employs N2(g) to control the evaporation of solvent from a micro-volume crystallization hanging drop. The number of crystals was found to vary with the rate at which the final supersaturation level was achieved. It was found that the more rapid the approach to supersaturation the larger the number of crystals. Accordingly, the crystals reached a smaller terminal size. Elongation of the (110) face parallel to the four-fold axis was observed with the slower evaporation rates.

  17. Evaporation and canopy characteristics of coniferous forests and grasslands

    Microsoft Academic Search

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

    1993-01-01

    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

  18. Normal evaporation of binary alloys

    NASA Technical Reports Server (NTRS)

    Li, C. H.

    1972-01-01

    In the study of normal evaporation, it is assumed that the evaporating alloy is homogeneous, that the vapor is instantly removed, and that the alloy follows Raoult's law. The differential equation of normal evaporation relating the evaporating time to the final solute concentration is given and solved for several important special cases. Uses of the derived equations are exemplified with a Ni-Al alloy and some binary iron alloys. The accuracy of the predicted results are checked by analyses of actual experimental data on Fe-Ni and Ni-Cr alloys evaporated at 1600 C, and also on the vacuum purification of beryllium. These analyses suggest that the normal evaporation equations presented here give satisfactory results that are accurate to within an order of magnitude of the correct values, even for some highly concentrated solutions. Limited diffusion and the resultant surface solute depletion or enrichment appear important in the extension of this normal evaporation approach.

  19. Evaporation of Liquid Hydrocarbon Mixtures on Titan

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  20. Evaporation of water from sodium chloride solutions under controlled climatic conditions

    E-print Network

    Moore, Jaroy

    1967-01-01

    nations 21 IV EXPERIMENTAL RESULTS 23 A. Evaporation Investigations B. Physical Model for Evaporation l. Evaporation rates 2. Vapor pressure of the solution 3. Vapor pressure of the air 4. Constant for wind speed C. Statistical Model... for Evaporation 23 27 27 27 28 28 34 D. Relation Between the Statistical and Physical Models 37 E. Effects of the Variables Employed l. Air temperature'e 2. Relative humidity 3 ~ Wind speed 4. Salt concentration 38 39 40 41 Chapter F. Reduction...

  1. Energy conservation in existing caustic evaporator house

    SciTech Connect

    Varshney, B.S.; Mathur, T.N.S.

    1983-12-01

    Process industries consume a major portion of the total energy used in industrial sector. Amongst the many other process industries 'Caustic Soda Manufacture' is the one which is highly energy-intensive. As a matter of fact it consumes fuel worth many millions of rupees in a year. Over the years the mercury cells have been replaced by diaphragm cells. One of the important factors contributing to this has been the availability of power and steam at cheap rates. In the diaphragm cells, the caustic soda produced comes out mixed with unelectrolysed salt and water known as cell liquor. The cell liquor contains varying percentage of NaOH, NaCl and water. It has a large amount of water (about 75% of the cell liquor) which is subsequently evaporated by steam in the multiple effect evaporator system depending upon the end-product concentration. Due to the large quantities of the water to be evaporated the cost of steam required for evaporation becomes so large that it controls the cost of caustic soda manufacture. Owing to many-fold escalation in the cost of fuel, over the last decade, the contribution of steam cost on the total cost of the product has further enhanced. This calls for a fresh look on the existing evaporators in order to reduce the steam consumption per tonne of caustic soda. In this paper, the important factors contributing to reduce the steam consumption for the economic operation of caustic evaporator from cell liquor concentration to 50% NaOH concentration are analysed.

  2. Metastatic insulinoma: current molecular and cytotoxic therapeutic approaches for metastatic well-differentiated panNETs.

    PubMed

    Giuroiu, Iulia; Reidy-Lagunes, Diane

    2015-02-01

    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

  3. Influence of Electron Evaporative Cooling on Ultracold Plasma Expansion

    E-print Network

    Wilson, Truman; Roberts, Jacob

    2013-01-01

    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. At lower densities (less than 10$^8$ /cm$^3$), evaporative cooling has a significant influence on the UCP expansion rate. 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.

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

    USGS Publications Warehouse

    Jobson, Harvey E.

    1980-01-01

    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)

  5. FIrDA-SSL: experiments with securing communication in PANs

    Microsoft Academic Search

    Diana Berbecaru

    2005-01-01

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

  6. The IPI PAN Corpus in Numbers Adam Przepirkowski

    E-print Network

    Przepiórkowski, Adam

    The IPI PAN Corpus in Numbers Adam Przepiórkowski Institute of Computer Science Polish Academy the IPI PAN Corpus (cf. http://korpus.pl/), a large morphosyntactically annotated XML encoded corpus and frequencies of grammatical classes and some grammatical categories. 1. Introduction The IPI PAN Corpus

  7. STEREO PANNING FEATURES FOR CLASSIFYING RECORDING PRODUCTION STYLE

    E-print Network

    Tzanetakis, George

    STEREO PANNING FEATURES FOR CLASSIFYING RECORDING PRODUCTION STYLE George Tzanetakis, Randy Jones stereo panning infor- mation is an important component of the production pro- cess. Audio classification information related to stereo panning. In this pa- per we propose a set of audio features that can be used

  8. Peroxyacetyl Nitrate (PAN) Measurements During the POPCORN Campaign

    Microsoft Academic Search

    W. Schrimpf; K. Linaerts; K. P. Müller; R. Koppmann; J. Rudolph

    1998-01-01

    During the POPCORN campaign between 3 and 24 August 1994 we measured peroxyacetyl nitrate (PAN) in a rural area of Mecklenburg-Vorpommern (North-Eastern Germany) above a corn field. A total of about 5000 PAN measurements were carried out within the three weeks of the campaign. Measured PAN mixing ratios ranged from below the detection limit of 10 ppt up to an

  9. Method of evaporation

    NASA Technical Reports Server (NTRS)

    Dufresne, Eugene R.

    1987-01-01

    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.

  10. Numerical competence in a chimpanzee (Pan troglodytes)

    Microsoft Academic Search

    Sarah T. Boysen; Gary G. Berntson

    1989-01-01

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

  11. The PAN-DA data acquisition system

    SciTech Connect

    Petravick, D.; Berg, D.; Berman, E.; Bernett, M.; Constanta-Fanourakis, P.; Dorries, T.; Haire, M.; Kaczar, K; MacKinnon, B.; Moore, C.; Nicinski, T.; Oleynik, G.; Pordes, R.; Sergey, G.; Votava, M.; White, V.

    1989-05-01

    The Online and Data Acquisition software groups at Fermi National Accelerator Laboratory have extended the VAXONLINE data acquisition package to include a VME based data path. The resulting environment, PAN-DA, provides a high throughput for logging, filtering, formatting and selecting events. 10 refs., 1 fig.

  12. Pan-Sharpening Based on QNR Optimization

    Microsoft Academic Search

    Muhammad Murtaza Khan; Luciano Alparone; Jocelyn Chanussot

    Quality Without Reference (QNR) index can be used to globally assess the quality of pan-sharpened images without the need of a reference high resolution multi-spectral (MS) image. The same index can be used on a local area if the area size is signiøcant as compared to the spatial resolution of the image. Exploiting this ability of QNR index, we propose

  13. Pattern formation in evaporating drops

    NASA Astrophysics Data System (ADS)

    Li, Fang-I.

    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.

  14. Droplet evaporation on heated hydrophobic and superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Dash, Susmita; Garimella, Suresh V.

    2014-04-01

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

  15. Small Scale Evaporation Kinetics of a Binary Fluid Mixture

    NASA Astrophysics Data System (ADS)

    Basdeo, Carl; Ye, Dezhuang; Kalonia, Devendra; Fan, Tai-Hsi; Mechanical Engineering Team; Pharmaceutical Sciences Collaboration

    2013-03-01

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

  16. Droplet evaporation on heated hydrophobic and superhydrophobic surfaces.

    PubMed

    Dash, Susmita; Garimella, Suresh V

    2014-04-01

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

  17. Thermal effects of the substrate on water droplet evaporation.

    PubMed

    Sobac, B; Brutin, D

    2012-08-01

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

  18. Multilayer composite material and method for evaporative cooling

    NASA Technical Reports Server (NTRS)

    Buckley, Theresa M. (Inventor)

    2002-01-01

    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.

  19. The saliva microbiome of Pan and Homo

    PubMed Central

    2013-01-01

    Background It is increasingly recognized that the bacteria that live in and on the human body (the microbiome) can play an important role in health and disease. The composition of the microbiome is potentially influenced by both internal factors (such as phylogeny and host physiology) and external factors (such as diet and local environment), and interspecific comparisons can aid in understanding the importance of these factors. Results To gain insights into the relative importance of these factors on saliva microbiome diversity, we here analyze the saliva microbiomes of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) from two sanctuaries in Africa, and from human workers at each sanctuary. The saliva microbiomes of the two Pan species are more similar to one another, and the saliva microbiomes of the two human groups are more similar to one another, than are the saliva microbiomes of human workers and apes from the same sanctuary. We also looked for the existence of a core microbiome and find no evidence for a taxon-based core saliva microbiome for Homo or Pan. In addition, we studied the saliva microbiome from apes from the Leipzig Zoo, and found an extraordinary diversity in the zoo ape saliva microbiomes that is not found in the saliva microbiomes of the sanctuary animals. Conclusions The greater similarity of the saliva microbiomes of the two Pan species to one another, and of the two human groups to one another, are in accordance with both the phylogenetic relationships of the hosts as well as with host physiology. Moreover, the results from the zoo animals suggest that novel environments can have a large impact on the microbiome, and that microbiome analyses based on captive animals should be viewed with caution as they may not reflect the microbiome of animals in the wild. PMID:24025115

  20. Evaporative cooling of the dipolar radical OH

    E-print Network

    Benjamin K. Stuhl; Matthew T. Hummon; Mark Yeo; Goulven Quéméner; John L. Bohn; Jun Ye

    2012-09-27

    Atomic physics was revolutionized by the development of forced evaporative cooling: it led directly to the observation of Bose-Einstein condensation, quantum-degenerate Fermi gases, and ultracold optical lattice simulations of condensed matter phenomena. More recently, great progress has been made in the production of cold molecular gases, whose permanent electric dipole moment is expected to generate rich, novel, and controllable phases, dynamics, and chemistry in these ultracold systems. However, while many strides have been made in both direct cooling and cold-association techniques, evaporative cooling has not yet been achieved due to unfavorable elastic-to-inelastic ratios and impractically slow thermalization rates in the available trapped species. We now report the observation of microwave-forced evaporative cooling of hydroxyl (OH) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least an order of magnitude in temperature and three orders in phase-space density, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique. With evaporative cooling and sufficiently large initial populations, much colder temperatures are possible, and even a quantum-degenerate gas of this dipolar radical -- or anything else it can sympathetically cool -- may now be in reach.

  1. Representative shuttle evaporative heat sink

    NASA Technical Reports Server (NTRS)

    Hixon, C. W.

    1978-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Xu, Xuefeng; Ma, Liran

    2015-02-01

    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.

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

    PubMed

    Xu, Xuefeng; Ma, Liran

    2015-01-01

    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. PMID:25721987

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

    PubMed Central

    Xu, Xuefeng; Ma, Liran

    2015-01-01

    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. PMID:25721987

  5. The desorptivity model of bulk soil-water evaporation

    NASA Technical Reports Server (NTRS)

    Clapp, R. B.

    1983-01-01

    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.

  6. Evaporative cooling of spin-polarized atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Masuhara, Naoto; Doyle, John M.; Sandberg, Jon C.; Kleppner, Daniel; Greytak, Thomas J.; Hess, Harald F.; Kochanski, Greg P.

    1988-08-01

    A gas hydrogen atoms, confined in a static magnetic trap, has been evaporatively cooled to temperatures of a few millikelvin. The initial trap configuration held the gas at 38 mK for as long as 5 h. Evaporative cooling reduced the temperature to 3.0 mK while maintaining the central density at 7.6×1012 cm-3. These values were determined by measurement of the rate of electronic spin relaxation and are in agreement with model calculations. Further cooling to 1 mK (inferred from the model) has been achieved. Measurements were made of the efficiency of the evaporative cooling process.

  7. Estimating evaporative vapor generation from automobiles based on parking activities.

    PubMed

    Dong, Xinyi; Tschantz, Michael; Fu, Joshua S

    2015-07-01

    A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade-Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5-8% less than calculation without considering parking activity. PMID:25818089

  8. Kinetic approach to the evaporation and condensation problem

    NASA Technical Reports Server (NTRS)

    Murakami, M.; Oshima, K.

    1974-01-01

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

  9. Evaporation and Thermal Balance of Tiny HI Clouds

    E-print Network

    Jonathan D. Slavin

    2006-10-10

    We discuss the thermal evaporation of tiny HI clouds in the interstellar medium. Cold neutral clouds will take ~10^6 - 10^7 yr to evaporate if they are embedded in warm neutral gas and about half as long if embedded in hot gas. Heat flux saturation effects severely reduce the evaporation rate of tiny cold neutral medium (CNM) clouds into hot gas. For CNM clouds embedded in warm neutral medium (WNM) the much lower conductivity results in slower evaporation. This mass loss rate could still be significant, however, if the environment is relatively quiescent. Partial ionization of the WNM gas would substantially reduce the conductivity and lengthen the lifetime of the tiny HI clouds. The ultimate importance of thermal conduction to cloud evolution will depend on the role of turbulence and the characteristics of the medium in which the clouds are embedded.

  10. Assessment of water droplet evaporation mechanisms on hydrophobic and superhydrophobic substrates.

    PubMed

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

    2013-12-23

    Evaporation rates are predicted and important transport mechanisms identified for evaporation of water droplets on hydrophobic (contact angle ~110°) and superhydrophobic (contact angle ~160°) substrates. Analytical models for droplet evaporation in the literature are usually simplified to include only vapor diffusion in the gas domain, and the system is assumed to be isothermal. In the comprehensive model developed in this study, evaporative cooling of the interface is accounted for, and vapor concentration is coupled to local temperature at the interface. Conjugate heat and mass transfer are solved in the solid substrate, liquid droplet, and surrounding gas. Buoyancy-driven convective flows in the droplet and vapor domains are also simulated. The influences of evaporative cooling and convection on the evaporation characteristics are determined quantitatively. The liquid-vapor interface temperature drop induced by evaporative cooling suppresses evaporation, while gas-phase natural convection acts to enhance evaporation. While the effects of these competing transport mechanisms are observed to counterbalance for evaporation on a hydrophobic surface, the stronger influence of evaporative cooling on a superhydrophobic surface accounts for an overprediction of experimental evaporation rates by ~20% with vapor diffusion-based models. The local evaporation fluxes along the liquid-vapor interface for both hydrophobic and superhydrophobic substrates are investigated. The highest local evaporation flux occurs at the three-phase contact line region due to proximity to the higher temperature substrate, rather than at the relatively colder droplet top; vapor diffusion-based models predict the opposite. The numerically calculated evaporation rates agree with experimental results to within 2% for superhydrophobic substrates and 3% for hydrophobic substrates. The large deviations between past analytical models and the experimental data are therefore reconciled with the comprehensive model developed here. PMID:24320680

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

    PubMed

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

    2014-08-19

    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

  12. The evaporative function of cockroach hygroreceptors.

    PubMed

    Tichy, Harald; Kallina, Wolfgang

    2013-01-01

    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

  13. Vegetation Cover Decreases Evaporative Water Loss in a Wetland Ecosystem

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  14. Impact of ambient conditions on evaporation from porous media

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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.

  15. Onset of Marangoni convection for evaporating liquids with spherical interfaces and finite boundaries.

    PubMed

    MacDonald, Brendan D; Ward, C A

    2011-10-01

    We examine the stability of liquids with spherical interfaces evaporating from funnels constructed of different materials. A linear stability analysis predicts stable evaporation for funnels constructed of insulating materials and introduces a stability parameter for funnels constructed of conducting materials. The stability parameter is free of fitting variables since we use the statistical rate theory expression for the evaporation flux. The theoretical predictions are found to be consistent with experimental observations for H(2)O evaporating from a funnel constructed of poly(methyl methacrylate) and for H(2)O and D(2)O evaporating from a funnel constructed of stainless steel. PMID:22181273

  16. Understanding the role of monolayers in retarding evaporation from water storage bodies

    NASA Astrophysics Data System (ADS)

    Fellows, Christopher M.; Coop, Paul A.; Lamb, David W.; Bradbury, Ronald C.; Schiretz, Helmut F.; Woolley, Andrew J.

    2015-03-01

    Retardation of evaporation by monomolecular films by a 'barrier model' does not explain the effect of air velocity on relative evaporation rates in the presence and absence of such films. An alternative mechanism for retardation of evaporation attributes reduced evaporation to a reduction of surface roughness, which in turn increases the effective vapour pressure of water above the surface. Evaporation suppression effectiveness under field conditions should be predictable from measurements of the surface dilational modulus of monolayers and research directed to optimising this mechanism should be more fruitful than research aimed at optimising a monolayer to provide an impermeable barrier.

  17. Climatological estimates of lake evaporation

    Microsoft Academic Search

    F. I. Morton

    1979-01-01

    A model for estimating areal evaporation and transpiration is modified slightly to provide estimates of annual lake evaporation from monthly observations of temperature, humidity, and sunshine duration (or radiation) in the land environment. The model estimates tend to be higher than the more conventional estimates in humid areas and lower in arid areas, with the latter tendency particularly noticeable in

  18. Evaporative cooling of sodium atoms

    Microsoft Academic Search

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

    1995-01-01

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

  19. DWPF Recycle Evaporator Simulant Tests

    Microsoft Academic Search

    2005-01-01

    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

  20. Modeling the motion and orientation of various pharmaceutical tablet shapes in a film coating pan using DEM.

    PubMed

    Ketterhagen, William R

    2011-05-16

    Film coating uniformity is an important quality attribute of pharmaceutical tablets. Large variability in coating thickness can limit process efficiency or cause significant variation in the amount or delivery rate of the active pharmaceutical ingredient to the patient. In this work, the discrete element method (DEM) is used to computationally model the motion and orientation of several novel pharmaceutical tablet shapes in a film coating pan in order to predict coating uniformity. The model predictions are first confirmed with experimental data obtained from an equivalent film coating pan using a machine vision system. The model is then applied to predict coating uniformity for various tablet shapes, pan speeds, and pan loadings. The relative effects of these parameters on both inter- and intra-tablet film coating uniformity are assessed. The DEM results show intra-tablet coating uniformity is strongly influenced by tablet shape, and the extent of this can be predicted by a measure of the tablet shape. The tablet shape is shown to have little effect on the mixing of tablets, and thus, the inter-tablet coating uniformity. The pan rotation speed and pan loading are shown to have a small effect on intra-tablet coating uniformity but a more significant impact on inter-tablet uniformity. These results demonstrate the usefulness of modeling in guiding drug product development decisions such as selection of tablet shape and process operating conditions. PMID:21356296

  1. Experimental Investigation of Microstructured Evaporators

    NASA Astrophysics Data System (ADS)

    Wibel, W.; Westermann, S.; Maikowske, S.; Brandner, J. J.

    2012-11-01

    Microfluidic devices have become more and more popular over the last decades [1]. Cooling is a topic where microstructures offer significant advantages compared to conventional techniques due the much higher possible surface to volume ratios and short heat transfer lengths. By evaporating of a fluid in microchannels, compact, fast and powerful cooling devices become possible [2]. Experimental results for different designs of microstructured evaporators are presented here. They have been obtained either using water as evaporating coolant or the refrigerant R134a (Tetrafluoroethane). A new microstructured evaporator design consisting of bended microchannels instead of straight channels for a better performance is shown and compared to previous results [2] for the evaporation of R134a in straight microchannels.

  2. BRDF of Salt Pan Regolith Samples

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

  4. Estimation of evaporative loss based on the stable isotope composition of water using Hydrocalculator

    NASA Astrophysics Data System (ADS)

    Skrzypek, Grzegorz; Myd?owski, Adam; Dogramaci, Shawan; Hedley, Paul; Gibson, John J.; Grierson, Pauline F.

    2015-04-01

    Accurate quantification of evaporative losses to the atmosphere from surface water bodies is essential for calibration and validation of hydrological models, particularly in remote arid and semi-arid regions, where intermittent rivers are generally minimally gauged. Analyses of the stable hydrogen and oxygen isotope composition of water can be used to estimate evaporative losses from individual pools in such regions in the absence of instrumental data but calculations can be complex, especially in highly variable systems. In this study, we reviewed and combined the most recent equations required for estimation of evaporative losses based on the revised Craig-Gordon model. The updated procedure is presented step-by-step, increasing ease of replication of all calculations. The main constraints and sources of uncertainties in the model were also evaluated. Based on this procedure we have designed a new software, Hydrocalculator, that allows quick and robust estimation of evaporative losses based on isotopic composition of water. The software was validated against measures of field pan evaporation under arid conditions in northwest Australia as well as published data from other regions. We found that the major factor contributing to the overall uncertainty in evaporative loss calculations using this method is uncertainty in estimation of the isotope composition of ambient air moisture.

  5. CHEMISTRY IN EVAPORATING ICES-UNEXPLORED TERRITORY

    SciTech Connect

    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

    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.

  6. Thermoelectric integrated membrane evaporation water recovery technology

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  7. Rapid Evaporation of microbubbles

    NASA Astrophysics Data System (ADS)

    Gautam, Jitendra; Esmaeeli, Asghar

    2008-11-01

    When a liquid is heated to a temperature far above its boiling point, it evaporates abruptly. Boiling of liquid at high temperatures can be explosive and destructive, and poses a potential hazard for a host of industrial processes. Explosive boiling may occur if a cold and volatile liquid is brought into contact with a hot and non-volatile liquid, or if a liquid is superheated or depressurized rapidly. Such possibilities are realized, for example, in the depressurization of low boiling point liquefied natural gas (LNG) in the pipelines or storage tanks as a result of a leak. While boiling of highly heated liquids can be destructive at macroscale, the (nearly) instantaneous pace of the process and the release of large amount of kinetic energy make the phenomena extremely attractive at microscale where it is possible to utilize the released energy to derive micromechanical systems. For instance, there is currently a growing interest in micro-explosion of liquid for generation of micro bubbles for actuation purposes. The aim of the current study is to gain a fundamental understanding of the subject using direct numerical simulations. In particular, we seek to investigate the boundary between stable and unstable nucleus growth in terms of the degree of liquid superheat and to compare the dynamics of unstable and stable growth.

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

    PubMed

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

    2014-01-01

    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

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

    PubMed

    Erbil, H Yildirim

    2012-01-15

    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

  10. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  11. Evaporative cooling of flare plasma

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  12. Microdroplet evaporation with a forced pinned contact line.

    PubMed

    Gleason, Kevin; Putnam, Shawn A

    2014-09-01

    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

  13. EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS

    SciTech Connect

    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

    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.

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

    SciTech Connect

    Woods, J.; Kozubal, E.

    2012-10-01

    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.

  15. WEB-BASED PPS 9.3 WEB-BASED PAN

    E-print Network

    Lee, Herbie

    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

  16. Detection and Behavior of Pan Wakes in Saturn's A Ring

    NASA Technical Reports Server (NTRS)

    Horn, L. J.; Showalter, M. R.; Russell, C. T.

    1996-01-01

    Six previously unseen Pan wakes are found interior and exterior to the Encke gap in Saturn's A ring, one in the Voyager 2 photopolarimeter (PPS) stellar occultation data and five in the Voyager 1 radio science (RSS) Earth occultation data. Pan orbits at the center of the Encke gap and maintains it...The detection of Pan wakes at longitudes greater than 360(deg) demonstrates that wakes persist for much longer than originally hypothesized and may interact with one another.

  17. Characteristic lengths affecting evaporative drying of porous media.

    PubMed

    Lehmann, Peter; Assouline, Shmuel; Or, Dani

    2008-05-01

    Evaporation from porous media involves mass and energy transport including phase change, vapor diffusion, and liquid flow, resulting in complex displacement patterns affecting drying rates. Force balance considering media properties yields characteristic lengths affecting the transition in the evaporation rate from a liquid-flow-based first stage limited only by vapor exchange with air to a second stage controlled by vapor diffusion through the medium. The characteristic lengths determine the extent of the hydraulically connected region between the receding drying front and evaporating surface (film region) and the onset of flow rate limitations through this film region. Water is displaced from large pores at the receding drying front to supply evaporation from hydraulically connected finer pores at the surface. Liquid flow is driven by a capillary pressure gradient spanned by the width of the pore size distribution and is sustained as long as the capillary gradient remains larger than gravitational forces and viscous dissipation. The maximum extent of the film region sustaining liquid flow is determined by a characteristic length L_{C} combining the gravity characteristic length L_{G} and viscous dissipation characteristic length L_{V} . We used two sands with particle sizes 0.1-0.5 mm ("fine") and 0.3-0.9 mm ("coarse") to measure the evaporation from columns of different lengths under various atmospheric evaporative demands. The value of L_{G} determined from capillary pressure-saturation relationships was 90 mm for the coarse sand and 140 mm for the fine sand. A significant decrease in drying rate occurred when the drying front reached the predicted L_{G} value (viscous dissipation was negligibly small in sand and L_{C} approximately L_{G} ). The approach enables a prediction of the duration of first-stage evaporation with the highest water losses from soil to the atmosphere. PMID:18643163

  18. A theoretical study of the spheroidal droplet evaporation in forced convection

    NASA Astrophysics Data System (ADS)

    Li, Jie; Zhang, Jian

    2014-11-01

    In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time.

  19. Heat Transfer Performance for Evaporator of Absorption Refrigerating Machine

    NASA Astrophysics Data System (ADS)

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

    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.

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

    PubMed

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

    2013-03-15

    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

  1. Explosive evaporation in solar flares

    NASA Technical Reports Server (NTRS)

    Fisher, George H.

    1987-01-01

    This paper develops a simple analytical model for the phenomenon of 'explosive evaporation' driven by nonthermal electron heating in solar flares. The model relates the electron energy flux and spectrum, plus details of the preflare atmosphere, to the time scale for explosive evaporation to occur, the maximum pressure and temperature to be reached, rough estimates for the UV pulse emission flux and duration, and the evolution of the blueshifted component of the soft X-ray lines. An expression is given for the time scale for buildup to maximum pressures and the onset of rapid motion of the explosively evaporating plasma. This evaporation can excite a rapid response of UV line and continuum emission. The emission lines formed in the plasma approach a given emissivity-weighted blueshift speed.

  2. Dual manifold heat pipe evaporator

    DOEpatents

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

    1994-01-04

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

  3. Dual manifold heat pipe evaporator

    DOEpatents

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

    1994-01-01

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

  4. Evaporation Tower With Prill Nozzles

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1984-01-01

    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.

  5. Evaporated Lithium Surface Coatings in NSTX

    SciTech Connect

    Kugel, H. W. [Princeton Plasma Physics Laboratory (PPPL); Mansfield, D. [Princeton Plasma Physics Laboratory (PPPL); Maingi, Rajesh [ORNL; Bell, M. G. [Princeton Plasma Physics Laboratory (PPPL); Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Allain, J. P. [Purdue University; Gates, D. [Princeton Plasma Physics Laboratory (PPPL); Gerhardt, S. P. [Princeton Plasma Physics Laboratory (PPPL); Kaita, R. [Princeton Plasma Physics Laboratory (PPPL); Kallman, J. [Princeton Plasma Physics Laboratory (PPPL); Kaye, S. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B. P. [Princeton Plasma Physics Laboratory (PPPL); Majeski, R. [Princeton Plasma Physics Laboratory (PPPL); Menard, J. [Princeton Plasma Physics Laboratory (PPPL); Mueller, D. [Princeton Plasma Physics Laboratory (PPPL); Ono, M. [Princeton Plasma Physics Laboratory (PPPL); Paul, S. [Princeton Plasma Physics Laboratory (PPPL); Raman, R. [University of Washington, Seattle; Roquemore, A. L. [Princeton Plasma Physics Laboratory (PPPL); Ross, P. W. [Princeton Plasma Physics Laboratory (PPPL); Sabbagh, S. A. [Columbia University; Schneider, H. [Princeton Plasma Physics Laboratory (PPPL); Skinner, C. H. [Princeton Plasma Physics Laboratory (PPPL); Soukhanovskii, V. [Lawrence Livermore National Laboratory (LLNL); Stevenson, T. [Princeton Plasma Physics Laboratory (PPPL); Timberlake, J. [Princeton Plasma Physics Laboratory (PPPL); Wampler, W. R. [Sandia National Laboratories (SNL); Wilgen, John B [ORNL; Zakharov, L. E. [Princeton Plasma Physics Laboratory (PPPL)

    2009-01-01

    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. (C) 2009 Elsevier B.V. All rights reserved

  6. Evaporated lithium surface coatings in NSTX.

    SciTech Connect

    Zakharov, L. (Princeton Plasma Physics Laboratory, Princeton, NJ); Gates, D. (Princeton Plasma Physics Laboratory, Princeton, NJ); Menard, J. (Princeton Plasma Physics Laboratory, Princeton, NJ); Maingi, R. (Oak Ridge National Laboratory, Oak Ridge, TN); Schneider, H. (Princeton Plasma Physics Laboratory, Princeton, NJ); Mueller, D. (Princeton Plasma Physics Laboratory, Princeton, NJ); Wampler, William R.; Roquemore, A. L. (Princeton Plasma Physics Laboratory, Princeton, NJ); Kallman, Jeffrey K. (Princeton Plasma Physics Laboratory, Princeton, NJ); Sabbagh, S. (Columbia University, New York, NY); LeBlanc, B. (Princeton Plasma Physics Laboratory, Princeton, NJ); Raman, R. (University of Washington, Seattle, WA); Ono, M. (Princeton Plasma Physics Laboratory, Princeton, NJ); Wilgren, J. (Oak Ridge National Laboratory, Oak Ridge, TN); Allain, J.P. (Purdue University, West Lafayette, IN); Timberlake, J. (Princeton Plasma Physics Laboratory, Princeton, NJ); Stevenson, T. (Princeton Plasma Physics Laboratory, Princeton, NJ); Ross, P. W. (Princeton Plasma Physics Laboratory, Princeton, NJ); Majeski, R. (Princeton Plasma Physics Laboratory, Princeton, NJ); Kugel, Henry W. (Princeton Plasma Physics Laboratory, Princeton, NJ); Skinner, C. H. (Princeton Plasma Physics Laboratory, Princeton, NJ); Gerhardt, S. (Princeton Plasma Physics Laboratory, Princeton, NJ); Paul, S. (Princeton Plasma Physics Laboratory, Princeton, NJ); Bell, R. (Princeton Plasma Physics Laboratory, Princeton, NJ); Kaye, S. M. (Princeton Plasma Physics Laboratory, Princeton, NJ); Kaita, R. (Princeton Plasma Physics Laboratory, Princeton, NJ); Soukhanovskii, V. (Lawrence Livermore National Laboratory, Livermore, CA); Bell, Michael G. (Princeton Plasma Physics Laboratory, Princeton, NJ); Mansfield, D. (Princeton Plasma Physics Laboratory, Princeton, NJ)

    2008-08-01

    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.

  7. Summertime distributions of peroxyacetyl nitrate (PAN) and peroxypropionyl nitrate (PPN) in Beijing: Understanding the sources and major sink of PAN

    NASA Astrophysics Data System (ADS)

    Zhang, Gen; Mu, Yujing; Zhou, Lingxi; Zhang, Chenglong; Zhang, Yuanyuan; Liu, Junfeng; Fang, Shuangxi; Yao, Bo

    2015-02-01

    Peroxyacetyl nitrate (PAN), a major secondary pollutant in the atmosphere, has received much concern for its particular importance in atmospheric chemistry and adverse effects on human and plants. Atmospheric PAN and PPN were measured by using a gas chromatograph equipped with electron capture detector (GC-ECD) from June to September 2010, and the source and major sink for PAN were firstly studied in Beijing. The distinct diurnal variations of PAN and PPN with maximum in the afternoon were observed, and the mean and maximum values were 2.61 ± 2.57 ppbv (N = 839) and 12.5 ppbv for PAN and 0.52 ± 0.38 ppbv (N = 152) and 2.16 ppbv for PPN during the measuring period, respectively. Good correlation (R = 0.85) between PAN and PPN with a slope (?PPN/?PAN) of 0.134 indicated that anthropogenic volatile organic compounds (AVOCs) dominated the photochemical formation of PANs in Beijing. Further, we found acetaldehyde was the predominant carbonyl precursor of PAN with the contribution of 59.7% to the total peroxyacetyl (PA) radical. Methyl glyoxal, methacrolein, acetone, methyl vinyl ketone, and biacetyl contributed 7.1%, 8.8%, 19.7%, 3.4%, and 1.3% to total PA radical, respectively. Anti-correlation between PAN concentrations and the NO/NO2 ratios was found during the whole investigating period. In addition, the amount of PAN lost by thermal decomposition (TPAN) accounted for remarkable fractions of PAN observed under high temperature during both daytime and nighttime.

  8. Modelling sub-daily evaporation from a small reservoir.

    NASA Astrophysics Data System (ADS)

    McGloin, Ryan; McGowan, Hamish; McJannet, David; Burn, Stewart

    2013-04-01

    Accurate quantification of evaporation from small water storages is essential for water management and is also required as input in some regional hydrological and meteorological models. Global estimates of the number of small storages or lakes (< 0.1 kilometers) are estimated to be in the order of 300 million (Downing et al., 2006). However, direct evaporation measurements at small reservoirs using the eddy covariance or scintillometry techniques have been limited due to their expensive and complex nature. To correctly represent the effect that small water bodies have on the regional hydrometeorology, reliable estimates of sub-daily evaporation are necessary. However, evaporation modelling studies at small reservoirs have so far been limited to quantifying daily estimates. In order to ascertain suitable methods for accurately modelling hourly evaporation from a small reservoir, this study compares evaporation results measured by the eddy covariance method at a small reservoir in southeast Queensland, Australia, to results from several modelling approaches using both over-water and land-based meteorological measurements. Accurate predictions of hourly evaporation were obtained by a simple theoretical mass transfer model requiring only over-water measurements of wind speed, humidity and water surface temperature. An evaporation model that was recently developed for use in small reservoir environments by Granger and Hedstrom (2011), appeared to overestimate the impact stability had on evaporation. While evaporation predictions made by the 1-dimensional hydrodynamics model, DYRESM (Dynamic Reservoir Simulation Model) (Imberger and Patterson, 1981), showed reasonable agreement with measured values. DYRESM did not show any substantial improvement in evaporation prediction when inflows and out flows were included and only a slighter better correlation was shown when over-water meteorological measurements were used in place of land-based measurements. Downing, J. A., Y. T. Prairie, J. J. Cole, C. M. Duarte, L. J. Tranvik, R. G. Striegl, W. H. McDowell, P. Kortelainen, N. F. Caraco, J. M. Melack and J. J. Middelburg (2006), The global abundance and size distribution of lakes, ponds, and impoundments, Limnology and Oceanography, 51, 2388-2397. Granger, R.J. and N. Hedstrom (2011), Modelling hourly rates of evaporation from small lakes, Hydrological and Earth System Sciences, 15, doi:10.5194/hess-15-267-2011. Imberger, J. and J.C. Patterson (1981), Dynamic Reservoir Simulation Model - DYRESM: 5, In: Transport Models for Inland and Coastal Waters. H.B. Fischer (Ed.). Academic Press, New York, 310-361.

  9. Insights into the Maize Pan-Genome and Pan-Transcriptome[W][OPEN

    PubMed Central

    Hirsch, Candice N.; Foerster, Jillian M.; Johnson, James M.; Sekhon, Rajandeep S.; Muttoni, German; Vaillancourt, Brieanne; Peñagaricano, Francisco; Lindquist, Erika; Pedraza, Mary Ann; Barry, Kerrie; de Leon, Natalia; Kaeppler, Shawn M.; Buell, C. Robin

    2014-01-01

    Genomes at the species level are dynamic, with genes present in every individual (core) and genes in a subset of individuals (dispensable) that collectively constitute the pan-genome. Using transcriptome sequencing of seedling RNA from 503 maize (Zea mays) inbred lines to characterize the maize pan-genome, we identified 8681 representative transcript assemblies (RTAs) with 16.4% expressed in all lines and 82.7% expressed in subsets of the lines. Interestingly, with linkage disequilibrium mapping, 76.7% of the RTAs with at least one single nucleotide polymorphism (SNP) could be mapped to a single genetic position, distributed primarily throughout the nonpericentromeric portion of the genome. Stepwise iterative clustering of RTAs suggests, within the context of the genotypes used in this study, that the maize genome is restricted and further sampling of seedling RNA within this germplasm base will result in minimal discovery. Genome-wide association studies based on SNPs and transcript abundance in the pan-genome revealed loci associated with the timing of the juvenile-to-adult vegetative and vegetative-to-reproductive developmental transitions, two traits important for fitness and adaptation. This study revealed the dynamic nature of the maize pan-genome and demonstrated that a substantial portion of variation may lie outside the single reference genome for a species. PMID:24488960

  10. Low-Volatility Compound Evaporation from the Deepwater Horizon Oil Spill

    NASA Astrophysics Data System (ADS)

    Koss, A.; De Gouw, J. A.; Warneke, C.

    2011-12-01

    The Deepwater Horizon (DWH) oil spill in April-August 2010 provided an unusual opportunity to study secondary organic aerosol (SOA) formation on a large scale. Chemicals with differing volatility, evaporating at different rates, were spatially separated and released to the atmosphere at different locations. The resulting distribution of vapor and aerosol phase organic compounds were measured during research flights of the NOAA WP-3D aircraft over the Gulf in June 2010 (de Gouw et al., 2011). Known volatile SOA precursors (C8 to C11 hydrocarbons) were measured in a thin plume downwind of DWH. SOA was measured in a much wider plume, indicating contributions from less volatile compounds evaporating further from the source. Estimates of semi- and intermediate- volatile compound evaporation rates from the oil spill have been improved using a component-wise first-order kinetics model in which the evaporation rate of a compound is proportional to both its vapor pressure and mole fraction. The model was validated through proton-transfer-reaction ion-trap mass spectrometer measurements of evaporating South Louisiana crude oil and calibration mixtures of aromatic compounds. These new evaporation rate estimates highlight several concepts important to a revised interpretation of the June 2010 aerosol measurements. The rates of evaporation (and thus atmospheric concentrations) of low-volatility compounds did not necessarily reflect surface distribution. Low volatility compounds reached peak evaporation rates at appreciable distances from the source, and the area from which significant amounts of chemical were emitted was larger than previously thought.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  13. Evaluation of a two-stage evaporation approximation for contrasting vegetation cover

    Microsoft Academic Search

    G. Boulet; A. Chehbouni; I. Braud; B. Duchemin; A. Lakhal

    2004-01-01

    For a regional assessment of water needs and consumption in semiarid agricultural zones, one needs robust and simple tools that provide space-time estimates of evaporation losses. Most operational evaporation estimates rely on semiempirical relationships that are not generally applicable. Several authors have proposed physically based simple expressions to model the “energy-limited” (stage-one) and the “supply-limited” (stage-two) evaporation rates during a

  14. Evaluation of a two-stage evaporation approximation for contrasting vegetation cover

    Microsoft Academic Search

    G. Boulet; A. Chehbouni; I. Braud; B. Duchemin; A. Lakhal

    2004-01-01

    For a regional assessment of water needs and consumption in semiarid agricultural zones, one needs robust and simple tools that provide space-time estimates of evaporation losses. Most operational evaporation estimates rely on semiempirical relationships that are not generally applicable. Several authors have proposed physically based simple expressions to model the ``energy-limited'' (stage-one) and the ``supply-limited'' (stage-two) evaporation rates during a

  15. Quantifying thick liquid films and their role in evaporative drying of porous media

    NASA Astrophysics Data System (ADS)

    Lehmann, P.; Willson, C.; Shokri, N.; Stampanoni, M.; Or, D.

    2007-12-01

    Evaporation rate from porous media is determined by a combination of driving forces and external conditions interacting with liquid and vapor within complex pore spaces. The evaporation rate during first stage of a drying process is controlled primarily by atmospheric demand and generally is not limited by medium transport properties. Liquid connections between the evaporation surface and the receding drying front sustain sufficient water supply to maintain a constant evaporation rate. When hydraulic connections are disrupted, water transport to the surface becomes limited to rates supported by vapor diffusion. To improve our understanding of the properties of stage-one supporting liquid connections, we delineated pore geometry and liquid configuration in sand samples imaged using synchrotron X-rays tomography. As air invades large pores, remaining liquid in crevices and grain contacts form a network of thick films. We compared evaporation rates with liquid phase configuration above the drying front in an attempt to relate the end of the first stage of drying with liquid films connectivity. The dependency of high evaporation rates on residual liquid continuity implies sensitivity to surface wettability properties. These effects were examined using different mixtures of hydrophobic and hydrophilic particles and their impact on drying rates and liquid phase distribution. Improved understanding of relationships between pore scale effects, liquid configuration and evaporation processes enhances predictability of drying rates and may enable alterations or design of porous media with prescribed drying behavior.

  16. Process-Aggravated Noise (PAN): New Validation and Test Problems

    Microsoft Academic Search

    Melvin A. Breuer; Sandeep K. Gupta

    1996-01-01

    How the trends in circuit design are increasing the significance of noise effects, such as crosstalk and ground bounce, is demonstrated. Further aggravated by process variations, these process aggravated noise (PAN) effects must be considered as an integral part of the design validation methodology. It is shown that the validation of a design in the presence of PAN effects requires

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  18. Detecting Earth-impacting asteroids Pan-STARRS prototype telescope

    E-print Network

    Veres, Peter

    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

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    Leeper, R. D.; Kochendorfer, J.

    2015-06-01

    Evaporation from a precipitation gauge can cause errors in the amount of measured precipitation. For automated weighing-bucket gauges, the World Meteorological Organization (WMO) suggests the use of evaporative suppressants and frequent observations to limit these biases. 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 U.S. Climate Reference Network (USCRN) stations. Two Geonor gauges were collocated, with one gauge using an evaporative suppressant (referred to as Geonor-NonEvap) and the other with no suppressant (referred to as Geonor-Evap) to evaluate evaporative losses and evaporation biases on precipitation measurements. From June to August, evaporative losses from the Geonor-Evap gauge exceeded accumulated precipitation, with an average loss of 0.12 mm h-1. The impact of evaporation on precipitation measurements was sensitive to the choice of calculation method. In general, the pairwise method that utilized a longer time series to smooth out sensor noise was more sensitive to gauge evaporation (-4.6% bias with respect to control) than the weighted-average method that calculated depth change over a smaller window (<+1% bias). These results indicate that while climate and gauge design affect gauge evaporation rates, computational methods also influence the magnitude of evaporation biases on precipitation measurements. This study can be used to advance quality insurance (QA) techniques used in other automated networks to mitigate the impact of evaporation biases on precipitation measurements.

  1. Combined flow and evaporation of fluid on a spinning disk

    NASA Astrophysics Data System (ADS)

    Birnie, Dunbar P., III; Manley, Manuel

    1997-04-01

    Fluid flow and fluid evaporation both contribute to the overall rate of thinning during spinning of a fluid on a disk. Laser interferometry of solvent thinning behavior on spinning silicon wafers was performed to yield plots of solvent thickness evolution. These plots of thickness versus time were then analyzed to understand the respective contributions of viscous flow and evaporation to the thinning. A technique is described for extracting both the viscosity and the evaporation rate from the interference data. Well understood solvent systems are examined as test cases for this deconvolution. It is also demonstrated that nonevaporating fluids can be analyzed, even though their thickness evolution has no easily referenced endpoint to the thinning, in contrast to the volatile solvents which are rapidly spun dry.

  2. Photodegradation studies of silver-backed polyacrylonitrile (PAN) films

    NASA Astrophysics Data System (ADS)

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

    1985-12-01

    Fourier transform infrared (IR) reflection-absorbance (RA) measurements are obtained to examine Ag-backed polyacrylonitrile (PAN) films, and the photodegradation of PAN is studied under oxidative and nonoxidative atmospheres in two experimental test chambers. The n and k optical constant values of the complex refractive index of PAN were determined as a function of wavenumber in the IR region, and the dependence of RA values on polymer functionality concentration is calculated as a function of film thickness. Derived IR-RA values are shown to be nearly linear with the concentration of functionalities for film thicknesses of up to 0.1 microns, and oxidative photodegradation pathways are proposed. A polyimine structure is generated at wavelengths of greater than 250 nm. PAN films of 1.0 wt. pct. Irganox 1010 and 0.5 wt. pct. Irgastab 2002 are seen to significantly retard the polymer photodegradation without affecting the PAN/Ag surface specularity.

  3. Theoretical and testing performance of an innovative indirect evaporative chiller

    SciTech Connect

    Jiang, Yi; Xie, Xiaoyun [Department of Building Science and Technology, Tsinghua University, Beijing (China)

    2010-12-15

    An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller successfully satisfy the indoor air conditioning load for the demo building. The indirect evaporative chiller has a potentially wide application in dry regions, especially for large scale commercial buildings. Finally, this paper presented the geographic regions suitable for the technology worldwide. (author)

  4. Evaporation Estimation of Rift Valley Lakes: Comparison of Models

    PubMed Central

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

    2009-01-01

    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

  5. Clinical evaluation of youth with pediatric acute-onset neuropsychiatric syndrome (PANS): recommendations from the 2013 PANS Consensus Conference.

    PubMed

    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

    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

  6. Numerical modeling of water flow and salt transport in bare saline soil subjected to evaporation

    NASA Astrophysics Data System (ADS)

    Geng, Xiaolong; Boufadel, Michel C.

    2015-05-01

    A numerical study, based on a density-dependent variably saturated groundwater flow model MARUN, was conducted to investigate subsurface flow and salt transport in bare saline aquifers subjected to evaporation, which was simulated using the bulk aerodynamic formulation. As evaporation was assumed to depend on the pore moisture, the evaporation flux evolved gradually causing a gradual increase in the pore salinity. This is in contrast to prior studies where the high salinity was imposed instantaneously on the ground surface. Key factors likely affecting subsurface hydrodynamics were investigated, including saturated hydraulic conductivity, capillary drive, relative humidity in the air, and surrounding groundwater replenishment. The simulations showed two temporal regimes where the first consists of rapid evaporation for a duration of hours followed by slow evaporation, until evaporation ceases. In the absence of surrounding groundwater replenishment, evaporation-induced density gradient generated an upward water flow initially, and then the flow decreased at which time a high density salt "finger" formed and propagated downwards. Capillary properties and atmospheric condition had significant impacts on subsurface moisture distribution and salt migration in response to the evaporation. The results also suggested that the presence of subsurface water replenishment to the evaporation zone tended to produce a steady evaporation rate at the ground surface.

  7. Water Evaporation Studies in Texas. 

    E-print Network

    Patterson, R. E. (Raleigh Elwood); Bloodgood, Dean W.; Smith, R. L.

    1954-01-01

    Water Evaporation Studies In Texas Isogram showing the relationship and comparison of evapor- ation losses from free-water surfaces and rainfall in Texas. in cooperation with the TEXAS BOARD OF WATER ENGINEERS and the U. S. DEPARTMENT... Brewster 2,100 29' 05' 103' 25' Maravillus Brewster 1,760 29' 30' 102' 50' Presidio Presidio 2,594 29' 30' 104' 25' 11) In cooperation with Lower Colorado River Authority, Austin 12) In cooperation with Water Department, City of Wichita Falls. 13...

  8. Evaporation heat transfer characteristics of a grooved heat pipe with micro-trapezoidal grooves

    Microsoft Academic Search

    A. J. Jiao; H. B. Ma; J. K. Critser

    2007-01-01

    A detailed mathematical model predicting the effect of contact angle on the meniscus radius, thin film profile and heat flux distribution occurring in the micro-trapezoidal grooves of a heat pipe has been presented. The model can be used to determine the maximum evaporating heat transfer rate in the evaporator including the effects of disjoining pressure and surface tension. The equation

  9. Physiological evaluation of the resistance to evaporative heat transfer by clothing

    Microsoft Academic Search

    INGVAR HOLMÉR; STURE ELNÄS

    1981-01-01

    A new method has been developed to determine the ‘effective’ evaporative resistance of clothing in vivo. It is based on direct measurements of the water vapour pressure gradient between skin and ambient air and of the steady state rate of evaporative heat loss. Air is sampled by a system of tubes terminating at six different loci on the skin surface

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

    PubMed Central

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

    2013-01-01

    The aim of this study was to evaluate a new type of occluder for patent ductus arteriosus. Patent ductus arteriosus was established in a canine model by anastomosing a length of autologous jugular vein to the descending aorta and the left pulmonary artery in an end-to-side fashion. Transcatheter closure of each patent ductus arteriosus was performed on 10 dogs, which were then monitored for as long as 6 months with aortography, echocardiography, and histologic evaluation. Transcatheter closure with use of the novel pan-nitinol device was successful in all canine models. Postoperative echocardiography showed that the location and shape of the occluders were normal, without any residual shunting. Further histologic evaluation confirmed that the occluder surface was completely endothelialized 3 months after implantation. Transcatheter patent ductus arteriosus closure with the pan-nitinol occluder can be performed safely and successfully in a canine model and shows good biological compatibility and low mortality rates. PMID:23466429

  11. Two-phase heat transfer analysis of evaporators

    Microsoft Academic Search

    José M. Corberán; José Gonzálvez

    2002-01-01

    Customary evaporator or condenser characterisation provides data concerning the circulating mass flow rate and inlet and outlet conditions for each fluid flow. This paper analyses the estimation, from those typical experimental results, of the average heat transfer coefficient (HTC) taking place during the phase change region and its corresponding uncertainty.This analysis shows the influence of the typical measurement uncertainties of

  12. Probing Light Dark Matter via Evaporation from the Sun

    E-print Network

    Chris Kouvaris

    2015-06-13

    Dark matter particles can be captured by the sun with rates that depend on the dark matter mass and the DM-nucleon cross section. However, for masses below $\\sim 3.3$ GeV, the captured dark matter particles evaporate, leading to an equilibrium where the rate of captured particles is equal to the rate of evaporating ones. Unlike dark matter particles from the halo, the evaporating dark matter particles have velocities that are not limited to values below the escape velocity of the galaxy. Despite the fact that high velocities are exponentially suppressed, I demonstrate here that current underground detectors have the possibility to probe/constrain low dark matter parameter space by (not)-observing the high energy tail of the evaporating dark matter particles from the sun. I also show that the functional form of the differential rate of counts with respect to the recoil energy in earth based detectors can identify precisely the mass and the cross section of the dark matter particle in this case.

  13. Wind effects on leaf transpiration challenge the concept of "potential evaporation"

    NASA Astrophysics Data System (ADS)

    Schymanski, S. J.; Or, D.

    2015-06-01

    Transpiration is commonly conceptualised as a fraction of some potential rate, driven by so-called "atmospheric evaporative demand". Therefore, atmospheric evaporative demand or "potential evaporation" is generally used alongside with precipitation and soil moisture to characterise the environmental conditions that affect plant water use. Consequently, an increase in potential evaporation (e.g. due to climate change) is believed to cause increased transpiration and/or vegetation water stress. In the present study, we investigated the question whether potential evaporation constitutes a meaningful reference for transpiration and compared sensitivity of potential evaporation and leaf transpiration to atmospheric forcing. A physically-based leaf energy balance model was used, considering the dependence of feedbacks between leaf temperature and exchange rates of radiative, sensible and latent heat on stomatal resistance. Based on modelling results and supporting experimental evidence, we conclude that stomatal resistance cannot be parameterised as a factor relating transpiration to potential evaporation, as the ratio between transpiration and potential evaporation not only varies with stomatal resistance, but also with wind speed, air temperature, irradiance and relative humidity. Furthermore, the effect of wind speed in particular implies increase in potential evaporation, which is commonly interpreted as increased "water stress", but at the same time can reduce leaf transpiration, implying a decrease in water demand at leaf scale.

  14. [Mineral migration from stainless steel, cast iron and soapstone (steatite) Brazilian pans to food preparations].

    PubMed

    Quintaes, Késia Diego; Farfan, Jaime Amaya; Tomazini, Fernanda Mariana; Morgano, Marcelo Antônio

    2006-09-01

    Culinary utensils may release some inorganic elements during food preparation. Mineral migration can be beneficial for as long as it occurs in amounts adequate to the needs of the consumer or no toxicological implications are involved. In this study, the migrations of Fe, Mg, Mn, Cr, Ni and Ca, along seven cooking cycles were evaluated for two food preparations (polished rice and commercial tomato sauce, the latter as an acid food), performed in unused stainless steel, cast iron and soapstone pans, taking refractory glass as a blank. Minerals were determined by inductively coupled plasma optical emission spectrometry (ICP OES). The utensils studied exhibited different rates, patterns and variability of migration depending on the type of food. Regression analysis of the data revealed that, as a function of the number of cycles, the iron pans released increasing amounts of iron when tomato sauce was cooked (y = 70.76x + 276.75; R2 = 0.77). The soapstone pans released calcium (35 and 26 mg/kg), magnesium (25 and 15 mg/kg) into the tomato sauce and rice preparations, respectively. Additionally, the commercial tomato sauce drew manganese (3.9 and 0.6 mg/kg) and some undesirable nickel (1.0 mg/kg) from the soapstone material, whereas the stainless steel pans released nickel at a lower rate than steatite and in a diminishing fashion with the number o cooking cycles, while still transferring some iron and chromium to the food. We conclude that while cast iron and glass could be best for the consumer's nutritional health, stainless steel and steatite can be used with relatively low risk, provided acid foods are not routinely prepared in those materials. PMID:17249489

  15. A diagram for the evaporation status of extrasolar planets

    E-print Network

    A. Lecavelier des Etangs

    2006-09-27

    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.

  16. Study on evaporation characteristics of a sessile drop of sulfur mustard on glass.

    PubMed

    Jung, Hyunsook; Myung, Sung Min; Park, Myung Kyu; Lee, Hae Wan; Ryu, Sam Gon

    2012-05-01

    The evaporation characteristics (evaporation rates and process) of a sessile drop of sulfur mustard on glass has been studied using a laboratory-sized wind tunnel, gas chromatograph mass spectrometry, and drop shape analysis. It showed that the evaporation rates of the droplet increased with temperature and air flow. The effect of temperature on the rates was more pronounced at lower air flow. Air flow was less effective at lower temperature. The contact angle of the droplet was initially observed as ? = 19.5° ± 0.7 and decreased linearly with time until it switched to a constant mode. PMID:22411175

  17. Evaporative cooling of speleothem drip water

    PubMed Central

    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

    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

  18. Evaporative cooling of speleothem drip water.

    PubMed

    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

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

  19. Pan1 is an intrinsically disordered protein with homotypic interactions

    PubMed Central

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

    2013-01-01

    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

  20. Thermal Evaporator (Edwards Auto 306)

    E-print Network

    Subramanian, Venkat

    Thermal Evaporator (Edwards Auto 306) Basic User Manual 3rd Edition Aug 2012 NR #12;Before Getting page of manual for start up instructions #12;Load the Chamber · Open chamber door. · Affix sample to sample and xtal #12;Load the Chamber · Press CYCLE · Wait for the display to read: FINE PUMPING · When

  1. Membrane evaporator/sublimator investigation

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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.

  2. Micromachined evaporators for AMTEC cells

    SciTech Connect

    Izenson, M.G.; Crowley, C.J. [Creare Inc., Hanover, NH (United States)

    1996-12-31

    To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads to very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.

  3. Operational estimates of lake evaporation

    Microsoft Academic Search

    F. I. MORTON

    1983-01-01

    Morton, F.I., 1983. Operational estimates of lake evaporation. J. Hydrol., 66: 77-- 100. The complementary relationship between areal and potential evapotranspiration takes into account the changes in the temperature and humidity of the air as it passes from a land environment to a lake environment. Minor changes convert the latest version of the complementary relationship areal evapotranspiration (CRAE) models to

  4. Forced-Flow Evaporative Cooler

    NASA Technical Reports Server (NTRS)

    Ellis, Wilbert E.; Niggemann, Richard E.

    1987-01-01

    Evaporative cooler absorbs heat efficiently under unusual gravitational conditions by using centrifugal force and vapor vortexes to maintain good thermal contact between heat-transfer surface and vaporizable coolant. System useful for cooling electronic or other equipment under low gravity encountered in spacecraft or under multiple-gravity conditions frequently experienced in high-performance airplanes.

  5. Fluid evaporation monitoring with suspended-core fibers

    NASA Astrophysics Data System (ADS)

    Moura, J. P.; Baierl, H.; Auguste, J.-L.; Jamier, R.; Roy, P.; Santos, J. L.; Frazão, O.

    2014-08-01

    A new configuration for volatile organic compound sensing is proposed. A sub-milimiter four-hole suspended core optical fiber tip, spliced to a standard single mode fiber, is dipped in a liquid volatile compound and the reflected signal is continuously interrogated. When the fiber is immersed in acetone it suffers a 14 dB signal drop. Different menisci form in each cladding cavity, with different evaporation times and rates. The signal restores its initial state not when the evaporation process is complete but after the collapse of a dominant meniscus.

  6. Evaporation and condensation at a liquid surface. II. Methanol

    NASA Astrophysics Data System (ADS)

    Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

    1994-11-01

    The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

  7. Modelling of lake mixing induced by air-bubble plumes and the effects on evaporation

    NASA Astrophysics Data System (ADS)

    Helfer, Fernanda; Zhang, Hong; Lemckert, Charles

    2011-09-01

    SummaryOne of the main concerns regarding water storage in Australia, and other semi-arid countries, is the high rate of evaporation that inevitably leads to significant water loss. In this paper, the use of air-bubble plume systems to reduce evaporation from large reservoirs is assessed. A destratification system was designed for a large dam based on its depth and stratification strength with the intention of destratifying the reservoir in a short time period. The model DYRESM was then used to simulate the water dynamics under destratification conditions. Different strategies for the operation of the aeration system were assessed, from 10-days operation periods at times of high evaporation rates to continuous operation over longer time spans. The modelled water column temperatures and evaporation rates were analysed and it was found that artificial destratification was only effective in reducing evaporation in spring. In summer, heat is added to the water at a rapid rate, and artificial destratification only helps reduce evaporation in the initial days of operation. The effect of artificial destratification in reducing evaporation in autumn depends on the operation of the system during summer. If operated in summer, the rates of evaporation in autumn will increase due to the additional heat added to the water during the summer. In winter, overturn takes place and artificial destratification has no influence on water temperatures and evaporation. It was concluded that aeration by air-bubble plumes would only be effective in reducing evaporation if the hypolimnetic water does not become warm when mixing takes place. This is an ideal situation, but is unlikely to happen in practice.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  9. PanCam for the ESA Lunar Lander 28 October 2011

    E-print Network

    Anand, Mahesh

    PanCam for the ESA Lunar Lander 28 October 2011 RAS, Picadilly UCL-MSSL Presented by: , A Aerospace Centre (DLR), Institute of Planetary Research, Germany 4Space Exploration Institute (SPACE Attributes of PanCam PanCam plays a key role as part of the lander payload: · PanCam sets the geological

  10. Practical Pure Pan and Pure Tilt Camera Calibration Imran N. Junejo

    E-print Network

    Foroosh, Hassan

    Practical Pure Pan and Pure Tilt Camera Calibration Imran N. Junejo IRISA/INRIA Rennes, France@cs.ucf.edu Abstract Often the deployed pan-tilt-zoom (PTZ) cameras un- dergo a pure pan or pure tilt rotation to estimate five cam- era parameters from these pure pan/tilt cameras by us- ing only two images. Our solution

  11. Electronic Pan-Tilt-Zoom: A Solution for Intelligent Room Systems Mircea Nicolescu and Grard Medioni

    E-print Network

    Nicolescu, Mircea

    Electronic Pan-Tilt-Zoom: A Solution for Intelligent Room Systems Mircea Nicolescu and Gérard component that uses an electronic pan-tilt-zoom camera array, a background learning and foreground these principles to compare our electronic pan-tilt-zoom camera with two other current solutions ­ mobile pan

  12. Soybean root morphology in soils with and without tillage pans in the lower Mississippi river valley

    Microsoft Academic Search

    T. C. Keisling; J. T. Batchelor; O. A. Porter

    1995-01-01

    During 1980, an extremely dry growing season, soybean (Glycine max L. Merrill) root morphologies were characterized at the R2 growth stage in Steele, Sharkey, Rilla, Calloway, and Stuttgart soils with a tillage pan and with a disrupted tillage pan. Results showed that the presence or absence of tillage pans resulted in dramatic changes in the soybean root morphology. Without pans,

  13. Synthesis on evaporation partitioning using stable isotopes

    NASA Astrophysics Data System (ADS)

    Coenders-Gerrits, Miriam; Bogaard, Thom; Wenninger, Jochen; Jonson Sutanto, Samuel

    2015-04-01

    Partitioning of evaporation into productive (transpiration) and non-productive evaporation (interception, soil evaporation) is of highest importance for water management practices, irrigation scheme design, and climate modeling. Despite this urge, the magnitude of the ratio of transpiration over total evaporation is still under debate and poorly understood due to measuring difficulties. However, with the current development in isotope measuring devices, new opportunities arise to untangle the partitioning of evaporation. In this paper we synthesize the opportunities and limitations using stable water isotopes in evaporation partitioning. We will analyze a set of field as well as laboratory studies to demonstrate the different evaporation components for various climate and vegetation conditions using stable isotopes 18O/16O and 2H/1H. Experimental data on evaporation partitioning of crops, grass, shrubs and trees are presented and we will discuss the specific experimental set-ups and data collection methods. The paper will be a synthesis of these studies.

  14. Steam Oxidation and Chromia Evaporation in Ultra-Supercritical Steam Boilers and Turbines

    SciTech Connect

    Gordon H. Holcomb

    2009-01-01

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

  15. Influence of Oil on Refrigerant Evaporator Performance

    NASA Astrophysics Data System (ADS)

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

    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.

  16. Measurements of PANs during the New England Air Quality Study 2002

    NASA Astrophysics Data System (ADS)

    Roberts, J. M.; Marchewka, M.; Bertman, S. B.; Sommariva, R.; Warneke, C.; de Gouw, J.; Kuster, W.; Goldan, P.; Williams, E.; Lerner, B. M.; Murphy, P.; Fehsenfeld, F. C.

    2007-10-01

    Measurements of peroxycarboxylic nitric anhydrides (PANs) were made during the New England Air Quality Study 2002 cruise of the NOAA RV Ronald H Brown. The four compounds observed, PAN, peroxypropionic nitric anhydride (PPN), peroxymethacrylic nitric anhydride (MPAN), and peroxyisobutyric nitric anhydride (PiBN) were compared with results from other continental and Gulf of Maine sites. Systematic changes in PPN/PAN ratio, due to differential thermal decomposition rates, were related quantitatively to air mass aging. At least one early morning period was observed when O3 seemed to have been lost probably due to NO3 and N2O5 chemistry. The highest O3 episode was observed in the combined plume of isoprene sources and anthropogenic volatile organic compounds (VOCs) and NOx sources from the greater Boston area. A simple linear combination model showed that the organic precursors leading to elevated O3 were roughly half from the biogenic and half from anthropogenic VOC regimes. An explicit chemical box model confirmed that the chemistry in the Boston plume is well represented by the simple linear combination model. This degree of biogenic hydrocarbon involvement in the production of photochemical ozone has significant implications for air quality control strategies in this region.

  17. Important pharmacophoric features of pan PPAR agonists: common chemical feature analysis and virtual screening.

    PubMed

    Sundriyal, Sandeep; Bharatam, Prasad V

    2009-09-01

    HipHop program was used to generate a common chemical feature hypothesis for pan Peroxisome Proliferator-Activated Receptor (PPAR) agonists. The top scoring hypothesis (hypo-1) was found to differentiate the pan agonists (actives) from subtype-specific and dual PPAR agonists (inactives). The importance of individual features in hypo-1 was assessed by deleting a particular feature to generate a new hypothesis and observing its discriminating ability between 'actives' and 'inactives'. Deletion of aromatic features AR-1 (hypo-1b), AR-2 (hypo-1e) and a Hydrophobic feature HYD-1 (hypo-1c) individually did not affect the discriminating power of the hypo-1 significantly. However, deletion of a Hydrogen Bond Acceptor (HBA) feature (hypo-1f) in the hydrophobic tail group was found to be highly detrimental for the specificity of hypo-1 leading to high hit rate of 'inactives'. Since hypo-1 did not produce any useful hits from the database search, hypo-1b, hypo-1c and hypo-1e were used for virtual screening leading to the identification of new potential pan PPAR ligands. The docking studies were used to predict the binding pose of the proposed molecules in PPARgamma active site. PMID:19268404

  18. Black Hole Evaporation as a Nonequilibrium Process

    Microsoft Academic Search

    Hiromi Saida

    2008-01-01

    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

  19. Laser evaporation of metal in gaseous atmosphere

    NASA Astrophysics Data System (ADS)

    Igoshin, V. I.; Kurochkin, V. I.

    1985-08-01

    A gasdynamic theory is presented of the evaporation of metals by laser radiation in a wide range of external pressures for power densities of 1 to 100 MW/sq cm. The boundary between the supersonic gasdynamic and the diffusive evaporation regimes is established. The results of numerical calculations of the evaporation of aluminum and iron are presented.

  20. Isotopic Compositions of Evaporative Fluxes

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  1. RESEARCH ARTICLE Parasitological Analyses of the Male Chimpanzees (Pan

    E-print Network

    Muehlenbein, Michael

    RESEARCH ARTICLE Parasitological Analyses of the Male Chimpanzees (Pan troglodytes schweinfurthii of primate ecological parasitology are warranted. For meaningful comparisons to be made, it is important Wiley-Liss, Inc. Key words: intestinal parasites; chimpanzee; parasite richness; ecological parasitology

  2. Localization of pan-cadherin immunoreactivity in adult rat tissues.

    PubMed

    Filiz, Serdar; Dalcik, Hakki; Yardimoglu, Melda; Gonca, Suheyla; Ceylan, Sureyya

    2002-01-01

    Cadherins, being responsible for selective cell recognition and normal tissue integrity in adults, regulate morphogenesis in a variety of organs during development. In this study, anti-rat pan-cadherin antibody, specific to all subgroups of the cadherin family, was used to map the distribution of the pan-cadherin immunoreactivity in adult rat organs. Pan-cadherin immunoreactivity positive tissues were: secretory cells of the adenohypophysis, autonomic nerve, corneal epithelium, oesophageal nerve plexus, stomach and pyloric glandular cells, epithelium of the ileum and its nerve plexus, alveolar cells of the lung, proximal convoluted tubules of the kidney, islet cells of Langerhans, and the acinar cells of the exocrine pancreas. For the first time, positive pan-cadherin immunoreactivity was demonstrated in the epithelial cells of the corpus ciliaris and in the nerve plexus of corpus cavernosum of the penis. In conclusion, our results suggest that cells in many tissues and organs of the adult rat synthesize cadherins. PMID:12468390

  3. Towards a Pan-European property index : methodological opportunities

    E-print Network

    Helfer, Friederike, 1976-

    2004-01-01

    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 ...

  4. STEREO Sees Comet Pan-STARRS - Duration: 33 seconds.

    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...

  5. Photodegradation studies of silver-backed polyacrylonitrile (PAN) films

    SciTech Connect

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

    1985-07-01

    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.

  6. Field trial of three different Plasmodium vivax-detecting rapid diagnostic tests with and without evaporative cool box storage in Afghanistan

    PubMed Central

    2011-01-01

    Background Accurate parasitological diagnosis of malaria is essential for targeting treatment where more than one species coexist. In this study, three rapid diagnostic tests (RDTs) (AccessBio CareStart (CSPfPan), CareStart PfPv (CSPfPv) and Standard Diagnostics Bioline (SDBPfPv)) were evaluated for their ability to detect natural Plasmodium vivax infections in a basic clinic setting. The potential for locally made evaporative cooling boxes (ECB) to protect the tests from heat damage in high summer temperatures was also investigated. Methods Venous blood was drawn from P. vivax positive patients in Jalalabad, Afghanistan and tested against a panel of six RDTs. The panel comprised two of each test type; one group was stored at room temperature and the other in an ECB. RDT results were evaluated against a consensus gold standard based on two double-read reference slides and PCR. The sensitivity, specificity and a measure of global performance for each test were determined and stratified by parasitaemia level and storage condition. Results In total, 306 patients were recruited, of which 284 were positive for P. vivax, one for Plasmodium malariae and none for Plasmodium falciparum; 21 were negative. All three RDTs were specific for malaria. The sensitivity and global performance index for each test were as follows: CSPfPan [98.6%, 95.1%], CSPfPv [91.9%, 90.5%] and SDBPfPv [96.5%, 82.9%], respectively. CSPfPv was 16% less sensitive to a parasitaemia below 5,000/?L. Room temperature storage of SDBPfPv led to a high proportion of invalid results (17%), which reduced to 10% in the ECB. Throughout the testing period, the ECB maintained ~8°C reduction over ambient temperatures and never exceeded 30°C. Conclusions Of the three RDTs, the CSPfPan test was the most consistent and reliable, rendering it appropriate for this P. vivax predominant region. The CSPfPv test proved unsuitable owing to its reduced sensitivity at a parasitaemia below 5,000/?L (affecting 43% of study samples). Although the SDBPfPv device was more sensitive than the CSPfPv test, its invalid rate was unacceptably high. ECB storage reduced the proportion of invalid results for the SDBPfPv test, but surprisingly had no impact on RDT sensitivity at low parasitaemia. PMID:21696587

  7. Pan-cancer patterns of somatic copy-number alteration

    PubMed Central

    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

    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

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

    Microsoft Academic Search

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

    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

  9. A Pan-Indigenous Vision of Indigenous Studies

    E-print Network

    Masaquiza, Martina (Salaska Kechwa); B'alam, Pakal (Kaqchikel Mayan)

    2000-03-01

    A Pan-Indigenous Vision of Indigenous Studies Martina Masaquiza (Salasaka Kechwa) and Pakal B'alam (Kaqchikel Mayan) Ethnic identity in an economically integrating world is a complicated matter. A friend told us this story: There was a... of radio, television and technical materials that are practical, educational and culturally appropriate. And we need leaders who will fashion an inspiring vision of where we as indigenous peoples hope to go. Perhaps the greatest barrier to building a Pan...

  10. Dynamical evaporation of quantum horizons

    NASA Astrophysics Data System (ADS)

    Pranzetti, Daniele

    2013-08-01

    We describe the black hole evaporation process driven by the dynamical evolution of the quantum gravitational degrees of freedom resident at the horizon, as identified by the loop quantum gravity kinematics. Using a parallel with the Brownian motion, we interpret the first law of the quantum-dynamical horizon in terms of a fluctuation-dissipation relation applied to this fundamental discrete structure. In this way, the horizon evolution is described in terms of relaxation to an equilibrium state balanced by the excitation of Planck scale constituents of the horizon. We investigate the final stage of the evaporation process and show how, from this setting, the emergence of several conservative scenarios for the information paradox can be microscopically derived. Namely, the leakage of part of the horizon quantum geometry information prior to the Planckian phase and the stabilization of the hole surface shrinkage forming a massive remnant, which can eventually decay, are described.

  11. Dynamical evaporation of quantum horizons

    E-print Network

    Pranzetti, Daniele

    2013-01-01

    We describe the black hole evaporation process driven by the dynamical evolution of the quantum gravitational degrees of freedom resident at the horizon, as identified by the Loop Quantum Gravity kinematics. Using a parallel with the Brownian motion, we interpret the first law of quantum dynamical horizon in terms of a fluctuation-dissipation relation applied to this fundamental discrete structure. In this way, the horizon evolution is described in terms of relaxation to an equilibrium state balanced by the excitation of Planck scale constituents of the horizon. We investigate the final stage of the evaporation process and show how, from this setting, the emergence of several conservative scenarios for the information paradox can be microscopically derived. Namely, the leakage of part of the horizon quantum geometry information prior to the Planckian phase and the stabilization of the hole surface shrinkage forming a massive remnant, which can eventually decay, are described.

  12. Evaporative cooling of a guided rubidium atomic beam T. Lahaye, Z. Wang, G. Reinaudi, S. P. Rath, J. Dalibard, and D. Gury-Odelin

    E-print Network

    Dalibard, Jean

    Evaporative cooling of a guided rubidium atomic beam T. Lahaye, Z. Wang, G. Reinaudi, S. P. Rath, J. The relatively high collision rate 5 s-1 allows us to start forced evaporative cooling of the beam, leading the technique of evaporative cooling to an atomic beam. A high-flux, slow, and cold atomic beam, transversely

  13. Mobile evaporator corrosion test results

    Microsoft Academic Search

    A. Rozeveld; D. B. Chamberlain

    1997-01-01

    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,

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

    PubMed

    Zhong, Xin; Duan, Fei

    2014-11-26

    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

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

    NASA Astrophysics Data System (ADS)

    Ozawa, K.; Nagahara, H.

    2009-04-01

    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

  16. Manning Counterion Condensation and Evaporation

    NASA Astrophysics Data System (ADS)

    Yang, Qingbo; O'Shaughnessy, Ben

    2003-03-01

    Interactions between highly charged macromolecules are complicated by their counterions whose behavior is crucial to biological processes such as DNA hybridization and ligand binding to charged biomolecules. Counterions are central to fundamental properties of polyelectrolyte solutions and interfacial assemblies. One of the most dramatic and important phenomena in these situations is Manning counterion condensation: Manning found stiff highly charged polymers such as DNA are so attractive to their counterions that a certain fraction latter condense onto the polymer backbone, reducing the effective polymer charge density to a critical value and modifying its interactions with other charged objects. Numerics and experiments show this rather simple theory frequently works surprisingly well. Here we present theory analyzing the condensation phenomenon: we find that depending on conditions the condensation can be complete, partial or may entirely evaporate. In solutions of charged macromolecules, we find critical concentrations of polymers and salt where counterion evaporation onsets, modifying effective polymer charge densities. This impacts osmotic pressures, equilibrium constants of reacting polymers and other physical properties. We discuss how the Donnan Effect is modified as an illustration of counterion evaporation.

  17. 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

    ...preventing acts of terrorism, every country has a stake in regional security. The Pan American community also supports strong democracies and the development of alternative energy sources. The promotion of transparent and enduring democratic governance...

  18. 3 CFR 8495 - Proclamation 8495 of April 9, 2010. Pan American Day and Pan American Week, 2010

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...States' headquarters, the Pan American Union Building; and the bicentennials of four of our fellow republics: Argentina, Colombia, Mexico, and Chile. These milestones remind us of our shared histories of independence and interdependence,...

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

    NASA Astrophysics Data System (ADS)

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

    1989-03-01

    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).

  20. Chemical evolution of multicomponent aerosol particles during evaporation

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

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

    Microsoft Academic Search

    Shan Jin; Yuansuo Zheng; Guoxin Gao; Zhihao Jin

    2008-01-01

    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

  2. Pan Air Geometry Management System (PAGMS): A data-base management system for PAN AIR geometry data

    NASA Technical Reports Server (NTRS)

    Hall, J. F.

    1981-01-01

    A data-base management system called PAGMS was developed to facilitate the data transfer in applications computer programs that create, modify, plot or otherwise manipulate PAN AIR type geometry data in preparation for input to the PAN AIR system of computer programs. PAGMS is composed of a series of FORTRAN callable subroutines which can be accessed directly from applications programs. Currently only a NOS version of PAGMS has been developed.

  3. PAN’s Labyrinth: Molecular Biology of Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) PAN RNA, a Multifunctional Long Noncoding RNA

    PubMed Central

    Rossetto, Cyprian C.; Pari, Gregory S.

    2014-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic ?-herpesivrus, the causative agent of Kaposi’s sarcoma and body cavity lymphomas. During infection KSHV produces a highly abundant long non-coding polyadenylated RNA that is retained in the nucleus known as PAN RNA. Long noncoding RNAs (lncRNA) are key regulators of gene expression and are known to interact with specific chromatin modification complexes, working in cis and trans to regulate gene expression. Data strongly supports a model where PAN RNA is a multifunctional regulatory transcript that controls KSHV gene expression by mediating the modification of chromatin by targeting the KSHV repressed genome. PMID:25375885

  4. Welcome to the new Toronto Pan Am Sports Centre! At approximately 365,000 sq. ft. of athletic and recreational space, the Toronto Pan Am Sports Centre

    E-print Network

    Boonstra, Rudy

    Welcome to the new Toronto Pan Am Sports Centre! At approximately 365,000 sq. ft. of athletic and recreational space, the Toronto Pan Am Sports Centre (TPASC) will offer a wide range of world-class athletic to the Toronto Pan Am Sports Centre through payroll deduction, you will be eligible to access all

  5. Evaporator Development for an Evaporative Heat Pipe System

    NASA Technical Reports Server (NTRS)

    Peters, Leigh C.

    2004-01-01

    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.

  6. Sensitivity of potential evaporation estimates to 100 years of climate variability

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Ruud; Stagge, James; Tallaksen, Lena; Witte, Jan-Philip

    2015-04-01

    Evaporation from the vegetated surface is the largest loss term in many, if not the most, water balance studies on earth. As a consequence, an accurate representation of evaporation fluxes is required for appropriate quantification of surface runoff, the soil moisture budget, transpiration, recharge and groundwater processes. However, despite being a key component of the water balance, evaporation figures are usually associated with large uncertainties, as this term is difficult to measure or estimate by modeling. Many modeling frameworks have used the concept of potential evaporation, often estimated for different vegetation classes by multiplying the evaporation from a reference surface ('reference evaporation') with 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. We quantified 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. Our hydrological models are to varying extent regression models, which limits their general applicability, and the estimation of potential evaporation is closely linked to climate variability. With our analysis, we want to raise awareness and to provide a quantification of possible systematic errors that may be introduced in estimates of potential evaporation and in hydrological modeling studies due to straightforward application of i) the common two-step approach for potential evaporation specifically, and ii) fixed instead of time-variant model parameters in general. 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-analogue climate conditions.

  7. Multipartite model of evaporative cooling in optical dipole traps

    NASA Astrophysics Data System (ADS)

    Williams, Matthew J.; Fertig, Chad

    2015-02-01

    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 ? .

  8. Assessment of the Multi-Fluid Evaporator Technology

    NASA Astrophysics Data System (ADS)

    Quinn, Gregory; O'Connor, Edward

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    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.

  10. PEP725 Pan European Phenological Database

    NASA Astrophysics Data System (ADS)

    Koch, Elisabeth; Adler, Silke; Ungersböck, Markus; Zach-Hermann, Susanne

    2010-05-01

    Europe is in the fortunate situation that it has a long tradition in phenological networking: the history of collecting phenological data and using them in climatology has its starting point in 1751 when Carl von Linné outlined in his work Philosophia Botanica methods for compiling annual plant calendars of leaf opening, flowering, fruiting and leaf fall together with climatological observations "so as to show how areas differ". The Societas Meteorologicae Palatinae at Mannheim well known for its first European wide meteorological network also established a phenological network which was active from 1781 to 1792. Recently in most European countries, phenological observations have been carried out routinely for more than 50 years by different governmental and non governmental organisations and following different observation guidelines, the data stored at different places in different formats. This has been really hampering pan European studies, as one has to address many National Observations Programs (NOP) to get access to the data before one can start to bring them in a uniform style. From 2004 to 2005 the COST-action 725 was running with the main objective to establish a European reference data set of phenological observations that can be used for climatological purposes, especially climate monitoring, and detection of changes. So far the common database/reference data set of COST725 comprises 7687248 data from 7285 observation sites in 15 countries and International Phenological Gardens (IPG) spanning the timeframe from 1951 to 2000. ZAMG is hosting the database. In January 2010 PEP725 has started and will take over not only the part of maintaining, updating the database, but also to bring in phenological data from the time before 1951, developing better quality checking procedures and ensuring an open access to the database. An attractive webpage will make phenology and climate impacts on vegetation more visible in the public enabling a monitoring of vegetation development.

  11. Evaporation of a thin binary liquid film by forced convection into air and superheated steam

    NASA Astrophysics Data System (ADS)

    Nasr, Abdelaziz; Debbissi, Chokri; Nasrallah, Sassi Ben

    2010-08-01

    This paper deals with a numerical analysis of the evaporation of a thin binary liquid film by forced convection inside a channel constituted by two plates. The first plate is externally insulated and wetted by a thin water ethylene glycol film while the second is dry and isothermal. The first part is concerned with the effects of inlet ambiance conditions and the liquid concentration of ethylene glycol on the distribution of the velocity, temperature, concentrations profiles and the axial variation of the evaporation rate. The second part is focused on the inversion temperature point of the evaporation of binary liquid film. Results show that the inversion temperature phenomenon for the evaporation of binary liquid mixture is observed for high liquid concentration of ethylene glycol. The present results show that in the inlet temperature range considered here, the inversion temperature does not exit for the evaporation of pure ethylene glycol.

  12. Evaporative oxidation treatability test report

    SciTech Connect

    NONE

    1995-04-01

    In 1992, Congress passed the Federal Facilities Compliance Act that requires the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with the Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). In response to the need for mixed-waste treatment capacity where available off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed wastes with treatment options and develop a strategy for treatment of its mixed wastes. DOE-AL manages operations at nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment capacity to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste not only must address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. On the basis of recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (GJPO) are evaporative oxidation, thermal desorption, and treated wastewater evaporation. Rust Geotech, the DOE-GJPO prime contractor, was assigned to design and fabricate mobile treatment units (MTUs) for these three technologies and to deliver the MTUs to selected DOE-AL sites. To conduct treatability tests at the GJPO, Rust leased a pilot-scale evaporative oxidation unit from the Clemson Technical Center (CTC), Anderson, South Carolina. The purpose of this report is to document the findings and results of tests performed using this equipment.

  13. Solar Roof Cooling by Evaporation 

    E-print Network

    Patterson, G. V.

    1982-01-01

    : BLISTERS: o Bliste6s form when the roof temperatures reach 150 to 165. The gravel falls off the blister a~d this allows the ultra violet rays of the sun to dlrectly attack the asphalt. This causes the oils to dry out, cracking occurs, and roof problems... intermit the roof, then allowing it to eva8orate, we can tently, then allowing it to evaporate, we can pro cool the soof to within 10 0 to 12 of wet bulb. duce the same effect of cooling the interior of the With a 76 wet bulb, this means that we can...

  14. Night-time evaporation from a short-rotation willow stand

    NASA Astrophysics Data System (ADS)

    Iritz, Zinaida; Lindroth, Anders

    1994-05-01

    The aim of the present study was to quantify and analyse the evaporation during night-time in a willow ( Salix viminalis L.) short-rotation stand. Evaporation measurements were made throughout the 24 h period on 76 days during the 1988 growing season using the energy-balance/Bowen-ratio method. Canopy conductance was estimated using a rearranged form of the Penman combination equation. The mean hourly evaporation rate during daytime was 0.18 mm h -1 and the corresponding value during night-time was 0.013 mm h -1, about 7% of the daytime rate. The mean cumulative night-time evaporation was 0.12 mm per night or 4.3% of the mean daytime evaporation. The highest night-time evaporation occurred in September and October with 0.21 mm and 0.36 mm per night, respectively, some 30-35% of the daytime evaporation during these periods. Total night-time evaporation for the growing season was estimated as 21 mm. Night-time evaporation was controlled mainly by vapour pressure deficit and ventilation whereas net radiation had only a minor influence. The night-time canopy resistance was estimated for a shorter period when the canopy was completely closed (leaf area index around 5) and the soil evaporation could be assumed negligible. The canopy resistance ranged between 10 and 220 s m -1 depending on vapour pressure deficit. The dependence on vapour pressure deficit during night-time was similar to the dependence during daytime but with a much larger sensitivity during the dark period.

  15. PAN Among the Peaks: A preliminary analysis of new peroxyacetyl nitrate (PAN) measurements in Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    Callahan, S. L.; Fischer, E. V.; Zhou, Y.; Sive, B. C.

    2014-12-01

    Several different classes of organic nitrogen compounds are produced when volatile organic compounds (VOCs) are oxidized in the presence of nitrogen oxide radicals (NOx). The peroxyacyl nitrates and organic nitrates are particularly important as they serve as temporary or permanent sinks for NOx. PAN (peroxyacetyl nitrate, CH3C(O)O2NO2) is the most important NOx reservoir, and its eventual decomposition acts as a pathway by which NOx reaches the remote troposphere. The emissions from oil and gas extraction represent a new VOC regime that could change the local fate of NOx because the particular mix of VOCs emitted from oil and gas operations should favor PAN formation. We present new PAN observations from Rocky Mountain National Park (ROMO) for the period 11 July to 15 August. The observations were collected during the Colorado Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ). PAN was measured at ROMO with a custom built gas chromatograph with an electron capture detector (GC-ECD). At the time of submission, preliminary campaign mean and maximum PAN mixing ratios were 170 pptv and 1345 pptv respectively. Initial analyses of the data collected to date suggest that the maximum PAN mixing ratios at ROMO occurred on the afternoons of 22 and 23 July. Co-located measurements of VOCs on 22 July indicate that the elevated PAN coincided with elevated abundances light alkanes and other secondary species (O3 and alkyl nitrates). The ratio of i-pentane to n- pentane (?1) indicates that this air mass was strongly impacted by oil and gas production operations.

  16. Overview of ATLAS PanDA Workload Management

    SciTech Connect

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

    2011-01-01

    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.

  17. Enhancement of metallic silver monomer evaporation by the adhesion of polar molecules to silver nanocluster ions

    SciTech Connect

    Fagerquist, C.K.; Sensharma, D.K.; El-Sayed, M.A. [Univ. of California, Los Angeles, CA (United States); Rubio, A.; Cohen, M.L. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

    1995-05-11

    We have compared the metallic evaporation channels from metastable [Ag{sub X=5,7,11}(AgI){sub Y=1-4}]{sup +} clusters in the first field free region of a double focusing mass spectrometer with that of the corresponding pure metallic clusters, [Ag{sub X=5,7,11}]{sup +}. It is found that the presence of the polar AgI molecules increases the rate of silver monomer evaporation relative to that of silver dimer evaporation. Using thermodynamic expressions for the heat of evaporation of the different evaporation processes and assuming the absence of reverse activation energies, an expression for the difference between the activation energy of silver monomer and dimer evaporation is derived. It is shown that dipole/induced-dipole forces resulting from the presence of AgI polar molecules lead to an enhancement of silver monomer evaporation if the polarizability of the pure metallic cluster ions increases with the number of Jellium electrons. Our theoretical calculations of the static polarizabilities of [Ag{sub x}]{sup +}, using time dependent density functional theory within the local density approximation, shows a smooth increase in the polarizabilities with the number of the Jellium electrons in these clusters. Finally, we observe that the enhancement of Ag monomer evaporation per AgI needed is smaller for clusters with an even number of AgI molecules than with an odd number of them. 46 refs., 5 figs., 2 tabs.

  18. Aircraft measured oil evaporating from Gulf oil spill

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-05-01

    Following the Gulf of Mexico oil spill in April 2010, some hydrocarbons dissolved in the ocean, while other leaked hydrocarbons that did not dissolve evaporated into the atmosphere. Ryerson et al. describe airborne in situ measurements of the hydrocarbons in the atmosphere after the oil spill, during initial cleanup operations. By comparing the amounts of chemicals in the atmosphere with those in crude oil, they determined which compounds dissolved in the ocean and which evaporated; by measuring the rate at which the compounds reached the atmosphere, they could estimate that oil and gas were leaking into the Gulf at a rate of at least 32,600-47,700 barrels of fluid per day.

  19. Surface Evaporation Index Derived from Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Nishida, K.; Nemani, R. R.; Running, S. W.

    2001-12-01

    An algorithm for estimating surface evaporation index (EI), which is defined as a ratio of actual evapotranspiration rate (AET) to potential evapotranspiration rate (PET), was developed for a global periodic product by the Agua/MODIS sensor. It depends on a simple 2-source model of evaporation and transpiration over vegetated surfaces. EI of full vegetation is estimated from the canopy conductance model of Jarvis (1976), whereas EI of soil is estimated by the vegetation index - brightness temperature slope concept (VI-Ts). The actual EI for each pixel is determined by weighting average of these two. We produced prototype products by using NOAA/AVHRR conterminous US 14-day composites and validated them with field observations over the continent carried out by the AmeriFlux towers.

  20. Observations on an evaporative, elbow thermosyphon

    SciTech Connect

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

    1993-05-01

    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.

  1. Field trial of three different Plasmodium vivax- detecting rapid diagnostic tests with and without evaporative cool box storage in Afghanistan

    Microsoft Academic Search

    Amy FW Mikhail; Toby J Leslie; Mohammad I Mayan; Rohullah Zekria; Nader Mohammad; Mohammad A Hasanzai; Najibullah Safi; Christopher JM Whitty; Mark Rowland

    2011-01-01

    Background  Accurate parasitological diagnosis of malaria is essential for targeting treatment where more than one species coexist. In\\u000a this study, three rapid diagnostic tests (RDTs) (AccessBio CareStart (CSPfPan), CareStart PfPv (CSPfPv) and Standard Diagnostics\\u000a Bioline (SDBPfPv)) were evaluated for their ability to detect natural Plasmodium vivax infections in a basic clinic setting. The potential for locally made evaporative cooling boxes (ECB)

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

    NASA Astrophysics Data System (ADS)

    Murakami, Shigeki

    2010-05-01

    An enormous amount of evaporation from forest canopy is observed during rainfall as canopy interception. The evaporation rate often exceeds well over 10 mm h-1 that requires latent heat of five times solar constant (6814 W m-2 at 20°C). On top of that, evaporation rate is proportional to the rainfall intensity. Namely, once the saturation of canopy is reached, the ratio of canopy interception to gross rainfall remains constant during the rainfall regardless of the intensity of the storm, e.g. approximately 20% of the rainfall in a Japanese cypress stand. This enigmatic phenomenon includes several cardinal problems to solve. As for the mechanism of a huge amount of evaporation, Murakami (2006, 2007; J. Hydrol.) proposed splash droplet evaporation, and is supported by Dunkerley (2009; J. Hydrol.). As the size and the number of raindrops increase with rainfall intensity (Marshall-Palmer distribution), so does the number of splash droplets produced by raindrops hitting the canopy. A host of small droplets with huge combined surface area highly boost evaporation, which means water evaporates from the splash droplets as well as the canopy. However, unless water vapor above canopy is removed and transported somewhere else, water vapor saturates and evaporation stops. Makarieva and Gorshkov (2007; HESS) advocated a new theory that can elucidate an enormous amount of evaporation and water vapor transport termed "evaporative force" or "the Biotic Pump Theory"(BPT). Though they do not deal with evaporation during rain events explicitly, it is applicable to the evaporation for the period of rainfall, i.e. canopy interception. Molecular weight of H2O, 18, is smaller than the average value of air 29 that works for water vapor as buoyancy. As a result, water vapor is removed since it goes up by itself and condenses at the bottom of cloud. In the cloud latent heat is released that will be transported down to the canopy being pulled down with raindrops or in exchange for water vapor ascending from the canopy. It is postulated that both latent heat and water circulate between the canopy and the cloud. Though Makarieva and Gorshkov (2007) claims that forest makes rain inland due to the strong evaporation from forest that "sucks in" water vapor from the ocean, they give canopy interception only a one-line mention. Canopy interception is a major component of evapotranspiration from forest that enables forest to evaporate larger amount of water than other surfaces on the earth, and the Biotic Pump does not function without canopy interception. Conversely, the mechanism of canopy interception is not explainable without evaporative force, and the fundamental cause of canopy interception is evaporative force. BPT is strongly supported by the observational facts of canopy interception and the splash droplet evaporation hypothesis. The study of canopy interception can be used as the tool to verify evaporative force that has the high potential of the development in the atmospheric boundary layer study.

  3. Evaporation kinetics of CO2 laser heated fused silica

    NASA Astrophysics Data System (ADS)

    Elhadj, Selim; Matthews, M. J.; Yang, S. T.; Cooke, D.; Stolken, J. S.; Feit, M. D.

    2011-03-01

    Laser-based machining strategies of optical surfaces remain mostly empirical, yet, systematic and controlled studies that relate gas chemistry and surface temperature to evaporation kinetics are limited, especially at extreme temperatures (> 2800 K) reachedduringlaserirradiation . WepresentexperimentalresultsofCO 2 laser heating of silica in oxidizing and non-oxidizing environments, along with analysis of surface shape from which a near-equilibrium evaporation model is derived. Based on this model, temperature dependent enthalpies of evaporation are determined and compared to published results. This model reproduces experimental laser-etch rates, while still accounting for laser, mass transport, and gas chemistry parameters. Although heat and mass transport processes are complex and tightly coupled, general conditions for which such an approach can be used to guide laser-based evaporation will be presented. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.

  4. Modeling evaporation from porous media influenced by atmospheric processes

    NASA Astrophysics Data System (ADS)

    Mosthaf, K.; Baber, K.; Flemisch, B.; Helmig, R.

    2012-04-01

    Modeling evaporation processes from partially saturated soils into the ambient air is a challenging task. It involves usually a variety of interacting processes and depends on the multitude of properties of the fluids and of the porous medium. Often, the ambient free-flow and the porous-medium compartments are modeled separately with a specification of the evaporation rate as boundary condition. We have developed a coupling concept, which allows the combined modeling of a free-flow and a porous-medium system under non-isothermal conditions with the evaporative fluxes across the soil-atmosphere interface as model output. It is based on flux continuity and local thermodynamic equilibrium at the interface. Darcy's law for multiple phases is used in the porous medium, whereas the ambient air flow is modeled as a compositional single-phase Stokes system. The concept has been implemented in the numerical simulator DuMux. A comparison of simulated and measured data from wind tunnel experiments performed in the group of D. Or (ETH Zürich) will be shown. Furthermore, the impact of several parameters, such as a varying wind velocity, temperature or different soil properties on the evaporation process has been analyzed in a numerical parameter study. The results will be presented and discussed.

  5. Hydrodynamic Instabilities Produced by Evaporation

    NASA Astrophysics Data System (ADS)

    Romo-Cruz, Julio Cesar Ruben; Hernandez-Zapata, Sergio; Ruiz-Chavarria, Gerardo

    2012-11-01

    When a liquid layer (alcohol in the present work) is in an environment where its relative humidity is less than 100 percent evaporation appears. When RH is above a certain threshold the liquid is at rest. If RH decreases below this threshold the flow becomes unstable, and hydrodynamic cells develop. The aim of this work is to understand the formation of those cells and its main features. Firstly, we investigate how the cell size depends on the layer width. We also study how temperature depends on the vertical coordinate when the cells are present. An inverse temperature gradient is found, that is, the bottom of liquid layer is colder than the free surface. This shows that the intuitive idea that the cells are due to a direct temperature gradient, following a Marangoni-like process, does not work. We propose the hypothesis that the evaporation produce a pressure gradient that is responsible of the cell development. On the other hand, using a Schlieren technique we study the topography of the free surface when cells are present. Finally the alcohol vapor layer adjacent to the liquid surface is explored using scattering experiments, giving some insight on the plausibility of the hypothesis described previously. Authors acknowledge support by DGAPA-UNAM under project IN116312 ``Vorticidad y ondas no lineales en fluidos.''

  6. Conductive Thermal Interaction in Evaporative Cooling Process

    E-print Network

    Kim, B. S.; Degelman, L. O.

    1990-01-01

    BYUNGSEON S. KIM PhD Candidate Department of Architecture Texas ALM University College Station, Texas ABSTRACT It has long been recognized that evaporative cooling is an effective and logical substitute for mechanical cooling in hot.... Yellott , J. I., "Evaporative Cooling1', Proc. 5th National Passive Sola Conference, American Solar Energy Society, Portland, OR, 1981. 3. Kim, B.S., L.O. Degelman and H. Wu , "The Performance Calibration of the Evaporative Cooler due to Thermal...

  7. Evaporation from a sphagnum moss surface

    Microsoft Academic Search

    DALE S. NICHOLS; JAMES M. BROWN

    1980-01-01

    Nichols, D.S. and Brown, J.M., 1980. Evaporation from a sphagnum moss surface. J. Hydrol., 48: 289--302. Peat cores, 45cm in diameter, were collected from a sphagnum bog in northern Minnesota, and used to measure the effects of different temperatures and water levels on evaporation from a sphagnum moss surface in a growth chamber. Under all conditions, evaporation from the moss

  8. Spatially Resolved Evaporative Patterns from Water

    E-print Network

    Ienna, Federico; Pollack, Gerald H

    2011-01-01

    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.

  9. Nickel determination in saline matrices by ICP-AES after sorption on Amberlite XAD-2 loaded with PAN

    Microsoft Academic Search

    Sérgio L. C. Ferreira; Cristiane F. de Brito; Alailson F. Dantas; Neyla M. Lopo de Araújo; A. C. Spinola Costa

    1999-01-01

    In the present paper, a solid phase extraction system for separation and preconcentration of nickel (ng g?1) in saline matrices is proposed. It is based on the adsorption of nickel(II) ions onto an Amberlite XAD-2 resin loaded with 1-(2-pyridylazo)-2-naphthol (PAN) reagent. Parameters such as the pH effect on the nickel extraction, the effect of flow rate and sample volume on

  10. OPTIMAL SLICE SIZE FOR STREAMING REGIONS OF HIGH RESOLUTION VIDEO WITH VIRTUAL PAN\\/TILT\\/ZOOM FUNCTIONALITY

    Microsoft Academic Search

    Aditya Mavlankar; Pierpaolo Baccichet; David Varodayan; Bernd Girod

    High resolution digital imaging sensors are becoming more widespread. The challenges in delivering this high resolution content to the client are posed by limited resolu- tion of display panels and\\/or limited bit-rate for communi- cations. We propose a video coding scheme which enables virtual pan\\/tilt\\/zoom functionality during the streaming ses- sion. This way the server can adaptand stream only those

  11. 11Chandra 'Sees' a Distant Planet Evaporating NASA's Chandra Observatory

    E-print Network

    that the star CoRot-2a is a powerful X-ray source. This is unfortunate because it is also known that a planet as 50% the mass of the planet. By comparison, the mass of Jupiter is about 1.9 x 10 27 kilograms or 315) = 2.9 x 10 27 kilograms Problem 2 - Based on the rate at which the planet is being evaporated, about

  12. Radial Photon Trajectories Near an Evaporating Black Hole

    E-print Network

    Beth A. Brown; James Lindesay

    2008-02-12

    The radial motion of photons emitted near the horizon of a black hole that evaporates at a steady rate is examined. The space-time of the black hole is generated using non-orthogonal coordinates. It is shown that some photons that are initially drawn towards the singularity can escape falling into the horizon. The behaviors of various outgoing and ingoing photons are clearly demonstrated through the use of a Penrose diagram.

  13. 40 CFR 428.90 - Applicability; description of the pan, dry digestion, and mechanical reclaimed rubber subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...description of the pan, dry digestion, and mechanical reclaimed rubber subcategory. 428...CATEGORY Pan, Dry Digestion, and Mechanical Reclaimed Rubber Subcategory § 428...description of the pan, dry digestion, and mechanical reclaimed rubber subcategory....

  14. Recharge Rates and Chemistry Beneath Playas of the High Plains Aquifer - A Literature Review and Synthesis

    USGS Publications Warehouse

    Gurdak, Jason J.; Roe, Cassia D.

    2009-01-01

    Playas are ephemeral, closed-basin wetlands that are important zones of recharge to the High Plains (or Ogallala) aquifer and critical habitat for birds and other wildlife in the otherwise semiarid, shortgrass prairie and agricultural landscape. The ephemeral nature of playas, low regional recharge rates, and a strong reliance on ground water from the High Plains aquifer has prompted many questions regarding the contribution of recharge from playas to the regional aquifer. To address these questions and concerns, the U.S. Geological Survey, in cooperation with the Playa Lakes Joint Venture, present a review and synthesis of the more than 175 publications about recharge rates and chemistry beneath playas and interplaya settings. Although a number of questions remain regarding the controls on recharge rates and chemistry beneath playas, the results from most published studies indicate that recharge rates beneath playas are substantially (1 to 2 orders of magnitude) higher than recharge rates beneath interplaya settings. The synthesis presented here supports the conceptual model that playas are important zones of recharge to the High Plains aquifer and are not strictly evaporative pans. The major findings of this synthesis yield science-based implications for the protection and management of playas and ground-water resources of the High Plains aquifer and directions for future research.

  15. Turbulence And Evaporation In Clusters Of Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1989-01-01

    Report presents theoretical model of evaporation of cluster of drops of single-component liquid fuel in and of processes of exchange between cluster and gas surrounding it. Formulation of model has three components: description of conservation of mass, molecular species, and enthalpy in sphere of influence of each drop; description of conservation of mass, molecular species, and enthalpy in cluster volume; description of convective effects by use of differential equations expressing conservation of momentum for gases and drops. Results obtained from analysis show turbulence enhances evaporation and controlling factor in evaporation of very dense clusters. Practical implication of findings evaporation of fuel controlled more readily near fuel injector than farther along combustor.

  16. Apparatus and method for evaporator defrosting

    DOEpatents

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

    2001-01-01

    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.

  17. Structural Oil Pan With Integrated Oil Filtration And Cooling System

    DOEpatents

    Freese, V, Charles Edwin (Westland, MI)

    2000-05-09

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

  18. PanDA's Role in ATLAS Computing Model Evolution

    E-print Network

    Maeno, T; The ATLAS collaboration

    2014-01-01

    During Run 1 at the Large Hadron Collider from 2009-2013, the ATLAS experiment successfully met the computing challenge of accumulating, managing and analyzing a volume of data now exceeding 140 PB, processed at over 100 sites around the world, and accessed by thousands of physicists. This accomplishment required nimbleness and flexibility in the distributed computing infrastructure, both hardware and software, as the operational computing model evolved during the run based on experience. A critical enabler for this evolution was PanDA, the ATLAS workload management system used for production and distributed analysis. PanDA's capabilities were utilized and extended to dynamically and intelligently distribute data and processing workloads across ATLAS resources based on data popularity and resource availability, thereby 'flattening' an originally hierarchical computing model, in order to use resources more efficiently. A new round of PanDA development now taking place will continue to evolve the model for bett...

  19. Optimization of Pan Bread Prepared with Ramie Powder and Preservation of Optimized Pan Bread Treated by Gamma Irradiation during Storage.

    PubMed

    Lee, Heejeong; Joo, Nami

    2012-03-01

    This study was conducted to develop an optimal composite recipe for pan bread with ramie powder that has high sensory approval with all age groups and to estimate the DPPH radical scavenging activity and the pan bread shelf life after gamma irradiation. The sensory evaluation results showed significant differences in flavor (p<0.05), appearance (p<0.01), color (p<0.01), moistness (p<0.01), and overall quality (p<0.05) based on the amount of ramie powder added. As a result, the optimum formulations by numerical and graphical methods were calculated to be as follows: ramie powder 2.76 g (0.92%) and water 184.7 mL. Optimized pan bread with ramie powder and white pan bread were irradiated with gamma-rays at doses of 0, 10, 15, and 20 kGy. The total bacterial growth increased with the longer storage time and the least amount of ramie powder added. Consequently, these results suggest that the addition of ramie powder to pan bread provides added value to the bread in terms of increased shelf life. PMID:24471063

  20. Drop evaporation on superhydrophobic PTFE surfaces driven by contact line dynamics.

    PubMed

    Ramos, S M M; Dias, J F; Canut, B

    2015-02-15

    In the present study, we experimentally study the evaporation modes and kinetics of sessile drops of water on highly hydrophobic surfaces (contact angle ?160°), heated to temperatures ranging between 40° and 70 °C. These surfaces were initially constructed by means of controlled tailoring of polytetrafluoroethylene (PTFE) substrates. The evaporation of droplets was observed to occur in three distinct phases, which were the same for the different substrate temperatures. The drops started to evaporate in the constant contact radius (CCR) mode, then switched to a more complex mode characterized by a set of stick-slip events accompanied by a decrease in contact angle, and finally shifted to a mixed mode in which the contact radius and contact angle decreased simultaneously until the drops had completely evaporated. It is shown that in the case of superhydrophobic surfaces, the energy barriers (per unit length) associated with the stick-slip motion of a drop ranges in the nJ m(-1) scale. Furthermore, analysis of the evaporation rates, determined from experimental data show that, even in the CCR mode, a linear relationship between V(2/3) and the evaporation time is verified. The values of the evaporation rate constants are found to be higher in the pinned contact line regime (the CCR mode) than in the moving contact line regime. This behavior is attributed to the drop's higher surface to volume ratio in the CCR mode. PMID:25460699

  1. Net-rainfall and wet-canopy evaporation in a small selectively-logged rainforest catchment, Sabah, Malaysia.

    E-print Network

    Chappell, Nick A

    Net-rainfall and wet-canopy evaporation in a small selectively-logged rainforest catchment, Sabah of the selective removal of trees from a tropical rainforest on the rate of wet-canopy evaporation for an area reached the forest floor beneath the undisturbed remnants of rainforest (i.e., the protected areas), than

  2. CONTROL OF EVAPORATIVE DEMAND ON TRANSPIRING PLANTS I. SENSITIVITIES OF EVAPORATIVE DEMAND TO ENVIRONMENTAL FACTORS

    Microsoft Academic Search

    M. KITANO; H. ECUCHI

    KITANO M. and EGUCHI H. Control of evaporative demand on transpiring plants 1. Sensitivities of evaporative demand to environmental factors. BIOTRONICS 20, 53-64, 1991. Effects of environmental factors on evaporative demand (ED) were analyzed, and control characteristics of ED were simulated. ED was affected by the respective environmental factors of irradiance, air temperature, humidity and wind velocity, and the respective

  3. Mass spectral determination of phenylacetonitrile (PAN) levels in body tissues of adult desert locust, Schistocerca gregaria.

    PubMed

    Amwayi, Peris W; Masiga, Daniel K; Govender, Prem; Teal, Peter E A; Torto, Baldwyn

    2012-08-01

    Wings and legs of the gregarious desert locust, Schistocerca gregaria have been shown to be release sites of phenylacetonitrile (PAN), the major adult male-produced pheromone. However, there is limited information on the distribution of PAN within the locust. Here we show, using gas chromatography-mass spectrometry (GC-MS), that PAN occurs in nearly all body parts of both adult males and females of the locust in varying amounts. PAN was 20-fold more concentrated in males than in females. In females, PAN was concentrated more in the tarsal segments. The greatest amounts of PAN were in 2- and 3-week old female and male body parts, respectively. No trace of PAN was found in similar ages and sexes of the solitarious phase desert locust. Our results show that PAN is distributed in the body matrix of both sexes of gregarious phase locusts and suggest that no specific tissue is responsible for biosynthesis of the pheromone. PMID:22609420

  4. Pan-Cancer Analysis of APOBEC Mutagenesis - Dmitry A. Gordenin, TCGA Scientific Symposium 2014

    Cancer.gov

    Home News and Events Multimedia Library Videos Pan-Cancer Analysis of APOBEC Mutagenesis - Dmitry A. Gordenin Pan-Cancer Analysis of APOBEC Mutagenesis - Dmitry A. Gordenin, TCGA Scientific Symposium 2014 You will need Adobe Flash Player 8 or later

  5. MARKETING APPLICATIONS: Tourism Marketing, Pan-European Marketing and Brand Management

    E-print Network

    Escolano, Francisco

    Syllabus MARKETING APPLICATIONS: Tourism Marketing, Pan-European Marketing and Brand Management Summer 2011 Alicante, Spain Course MARKETING APPLICATIONS: Tourism Marketing, Pan-European Marketing Objectives This course examines three relevant applications of Marketing principles. Tourism Marketing

  6. Evaporation Mechanism of Sn and SnS from Liquid Fe: Part I: Experiment and Adsorption of S on Reaction Site

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    In order to evaluate feasibility of Sn-containing ferrous scrap recycling by evaporation of Sn, a number of liquid-gas experiments were carried out using an electromagnetic levitation melting technique. Rate of decrease of Sn concentration in liquid steel droplets by evaporation in Ar-H2 gas mixture was determined at 1873 K (1600 °C). Evaporation rate of the Sn under various conditions (various flow rates of the gas mixture, initial S concentration, [pct Sn]0) was examined using previously reported rate equations. Increasing flow rate increased the evaporation rate of Sn initially, but the rate became constant at higher flow rate, which indicates that the rate-controlling step is the chemical reaction at the liquid/gas interface. Increasing initial S concentration significantly increased the evaporation rate of Sn, which is in good agreement with previous understanding that Sn could be evaporated as SnS(g). It was found in the present study that neither a simple first-order reaction (rate proportional to [pct Sn]) nor a second-order reaction (rate proportional to [pct Sn] × [pct S]) could account for the Sn evaporation under a chemical-reaction-controlled regime. It is proposed in the present study that surface adsorption of S should be taken into account in order to interpret the evaporation rate of Sn in such a way that S blocks available sites for SnS evaporation on the liquid steel. The ideal Langmuir isotherm was applied in order to better represent evaporation rate constant k SnS as a function of [pct S] (0.06 < [pct S]0 < 0.29). The obtained rate constant of a reaction Sn i + S i = SnSi(g), , is 2.57 × 10-8 m4 mol-1 s-1.

  7. Heat Transfer and Convective Structure of Evaporating Films under Pressure-Modulated Conditions

    NASA Astrophysics Data System (ADS)

    Gonzalez, Juan Carlos

    This work examines the fluid mechanical and heat transfer characteristics of evaporating films under cyclical superheat conditions. This research was motivated by the need to further understand the instability drivers in films undergoing unsteady and cyclical evaporation. The superheat was controlled modulating the system pressure. An isolated test cell allowed the films to evaporate into their own vapor without non-condensable present. A non-intrusive thickness measurement technique was used to yield dynamic heat flux measurements. A double pass schlieren system was employed to capture convective structures. System temperature and pressure measurements completed the diagnostics. The primary conclusions are briefly summarized as follows: • The evolution of thermal profile within evaporating films has a strong impact on the development of convective structure and heat transfer. In some cases convective structure appears within the film under pressure-modulated conditions even when the evaporation intervals are sufficiently short that conduction is expected to be the only heat transfer mode within the film. • Convective structure appears to persist in many cases even after evaporation is stopped. • Stopping the evaporation for short time intervals appears to have a negligible effect on the temperature profile in the film based on the subsequent evaporation behavior. • Complex, multi-wavelength convective structure behavior can be induced through cyclical superheating of the films. • A modest gain in short-term heat flux is achievable under some pressure-modulated conditions. • Surface instabilities of quasi-steady evaporating films do not lead to an increase in the evaporation rate. • Reduced gravity tests were seriously compromised by unsteady g-levels and g-jitter.

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

    USGS Publications Warehouse

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

    2013-01-01

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

  9. Historical satellite data used to map Pan-Amazon forest cover

    NASA Astrophysics Data System (ADS)

    Kalluri, Satya; Desch, Arthur; Curry, Troy; Altstatt, Alice; Devers, Didier; Townshend, John; Tucker, Compton

    Deforestation in the Brazilian Amazon is well documented and the contributions of Brazilian deforestation to global change have been extensively discussed in both scientific and popular literature [e.g., Skole and Tucker, 1993]. However, deforestation within the non-Brazilian tropics of South America has received much less attention. The Pan-Amazon region covering Venezuela, Colombia, Ecuador, Peru, and Bolivia comprises ˜2 million km2 of tropical forest that is under increasing pressure from logging and development. Wall-to-wall high-resolution forest cover maps are needed to properly document the complex distribution patterns of deforestation in the Pan-Amazon [Tucker and Townshend, 2000]. The Deforestation Mapping Group at the University of Marylands Global Land Cover Facility is using Landsat data to generate tropical forest cover maps in this region (Figure l). The study shows that while rates of forest loss are generally lower than those in Brazil, there are hot spots where deforestation rates run as high as 2,200 km2 yr1.

  10. Evaporating Global Charges in Braneworld

    NASA Astrophysics Data System (ADS)

    Dvali, Gia; Gabadadze, Gregory

    2002-09-01

    In braneworld models the global charges, such as baryon or lepton number, are not conserved. The global-charge non-conservation is a rather model-independent feature which arises due to quantum fluctuations of the brane worldvolume. These fluctuations create ``baby branes'' that can capture some global charges and carry them away into the bulk of higher-dimensional space. Such processes are exponentially suppressed at low-energies, but can be significant at high enough temperatures or energies. These effects can lead to a new, intrinsically high-dimensional mechanism of baryogenesis. Baryon asymmetry might be produced due either to evaporation into the baby branes, or creation of the baryon number excess in collisions of two Brane Universes.

  11. Optical and structural properties of two-sourced evaporated ZnTe thin films

    NASA Astrophysics Data System (ADS)

    Aqili, Akram K. S.; Ali, Zulfiqar; Maqsood, Asghari

    2000-10-01

    Optical properties of ZnTe films, deposited by thermal evaporation of Zn and Te sources, were studied in the range of 400-2000 nm by UV-VIS-NIR spectrophotometer. Variations of refractive index with incident photon energy are fitted to a single oscillator model. Optical band gap and X-ray diffraction (XRD) have been reported for ZnTe films formed at substrate temperature of 300°C with different evaporation rates.

  12. Large-Eddy Simulation of Interactions Between a Reacting Jet and Evaporating Droplets

    Microsoft Academic Search

    Jun Xia; Kai H. Luo; Suresh Kumar

    2008-01-01

    Large-eddy simulation of a turbulent reactive jet with and without evaporating droplets is performed to investigate the interactions\\u000a among turbulence, combustion, heat transfer and evaporation. A hybrid Eulerian–Lagrangian approach is used for the gas–liquid\\u000a flow system. Arrhenius-type finite-rate chemistry is employed for the chemical reaction. To capture the highly local interactions,\\u000a dynamic procedures are used for all the subgrid-scale models,

  13. CHROMOSPHERIC EVAPORATION VIA ALFVEN WAVES

    SciTech Connect

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

    2009-12-20

    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.

  14. Measured and calculated evaporation losses of two petroleum hydrocarbon herbicide mixtures under laboratory and field conditions

    SciTech Connect

    Woodrow, J.E.; Seiber, J.N.; Kim, Y.

    1986-08-01

    Evaporation rates of two weed oils were measured under laboratory and field conditions. Rates were also calculated by assuming first-order evaporation of the oil components (represented by hydrocarbon references). Beacon selective and Chevron nonselective weed oils exhibited evaporation rates 1.4-1.9 and 0.9 times the calculated rates, respectively, for 8-10 mg/cm/sup 2/ on inert surfaces in the laboratory. The relative rates were increased to 3-15 (Beacon) and 1.6 (Chevron) under a slight breeze (0.43 m/s) with turbulence. The half-life of Beacon oil applied at 6-7 mg/cm/sup 2/ to moist soil in an unplanted field was 51 min (10-20/sup 0/C), while the calculated half-life was 57 min. In an alfalfa field, 90% of the Chevron oil from a deposit of 0.15-0.22 mg/cm/sup 2/ (20-40/sup 0/C) evaporated in 26-45 and 53-127 min from glass plates and paper filters, respectively; average calculated time was 40 min. Evaporation rates from alfalfa foliage and glass plates compared well. 15 references, 6 figures, 8 tables.

  15. PAN's Labyrinth: Molecular biology of Kaposi's sarcoma-associated herpesvirus (KSHV) PAN RNA, a multifunctional long noncoding RNA.

    PubMed

    Rossetto, Cyprian C; Pari, Gregory S

    2014-11-01

    Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic ?-herpesivrus, the causative agent of Kaposi's sarcoma and body cavity lymphomas. During infection KSHV produces a highly abundant long non-coding polyadenylated RNA that is retained in the nucleus known as PAN RNA. Long noncoding RNAs (lncRNA) are key regulators of gene expression and are known to interact with specific chromatin modification complexes, working in cis and trans to regulate gene expression. Data strongly supports a model where PAN RNA is a multifunctional regulatory transcript that controls KSHV gene expression by mediating the modification of chromatin by targeting the KSHV repressed genome. PMID:25375885

  16. Odors from evaporation of acidified pig urine

    Microsoft Academic Search

    H. C. Willers; P. J. Hobbs; N. W. M. Ogink

    2004-01-01

    In the Dutch Hercules project feces and urine from pigs are collected separately underneath the slatted floor in a pig house and treated in two processes. Feces are composted and urine is concentrated by water evaporation in a packed bed. Exhaust air from the pig house is used for the evaporation in a packed bed scrubber. Before entering the scrubber,

  17. More About Evaporation In Clusters Of Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1990-01-01

    Report presents theoretical study of evaporation in clusters of spray drops in liquid fuel. Related to reports described in "Turbulence and Evaporation in Clusters of Drops" (NPO-17323) and "Effects of Turbulence on Ignition" (NPO-17335). Purpose of study to improve theoretical description of transport of molecular species, mass, and heat between cluster and its surroundings.

  18. Mars-Analog Evaporite Experiment: Evaporation Results

    Microsoft Academic Search

    J. M. Moore; M. A. Bullock; T. G. Sharp

    2007-01-01

    This research is part of a multi-year experimental investigation of brines and evaporates on Mars. Here we report the results from our evaporites apparatus in which two types of brine were subjected to evaporation under Mars-like conditions.

  19. Advanced evaporator technology progress report FY 1992

    SciTech Connect

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

    1995-01-01

    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.

  20. Practical application of an evaporation duct model

    Microsoft Academic Search

    R. A. Paulus

    1985-01-01

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

  1. DWPF Recycle Evaporator Shielded Cells Testing

    Microsoft Academic Search

    T. L. Fellinger; D. T. Herman; M. E Stone

    2005-01-01

    Testing was performed to determine the feasibility and processing characteristics of evaporation of actual Defense Waste Processing Facility (DWPF) recycle material. Samples of the Off Gas Condensate Tank (OGCT) and Slurry Mix Evaporator Condensate Tank (SMECT) were transferred from DWPF to the Savannah River National Lab (SRNL) Shielded Cells and blended with De-Ionized (DI) water and a small amount of

  2. August 15, 1997 Density of Evaporated Milk

    E-print Network

    Santner, Thomas

    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

  3. Modeling of over Lake Wind Profile for Estimating Water Surface Evaporation Using Land-based meteorological Data

    NASA Astrophysics Data System (ADS)

    Abbasi, Ali; van de Giesen, Nick

    2013-04-01

    Evaporation from reservoirs and small lakes plays an important role in water management. Estimating the evaporation from surface water resources such as small lakes and reservoirs requires extensive data. Evaporation is difficult and expensive to measure experimentally over the water surface. For operational purposes it would be attractive if evaporation from a lake could be estimated with acceptable accuracy from standard meteorological data taken at nearby land-based stations. Several techniques and models have been suggested and used to estimate evaporation from open water bodies. One of the most commonly used methods is the aerodynamic mass transfer method which gives reliable results for water bodies if suitable data are available. With the aerodynamic approach, evaporation rate is modeled as the product of a vapor pressure deficit between the water surface and upwind air and a wind function that depends on the wind profile over the water surface. As measuring wind speed, and other meteorological data, over a water surface is not easy, most literature uses land-based meteorological measurements. Using land-based meteorological stations data in estimating evaporation introduces significant errors in estimated values of evaporation. On the other hand, the aerodynamic method should account for the size or fetch of a desired water body as evaporation rate decreases with distance downwind from the land-water edge due to increased entrainment of water vapor. Neglecting the fetch effects in this method introduce errors in estimated evaporation values. In this paper, we use a CFD model (RANS Model) to simulate the wind profile over the water surface that utilizes land-based measurements. The modeled wind profile is used to estimate evaporation from water surface using the aerodynamic approach. This proposed model is tested for small lakes and reservoirs in arid and semi-arid regions. Results show a good agreement with the experimental measurements and can be used in water management plans to estimate evaporation from reservoirs and small water bodies.

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

    SciTech Connect

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

    1997-11-01

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

  5. Radioimmunodetection of human pancreatic tumor xenografts using DU-PAN II monoclonal antibody.

    PubMed

    Nakamura, K; Kubo, A; Hashimoto, S; Furuuchi, T; Takami, H; Abe, O

    1988-05-01

    The potential of DU-PAN II, monoclonal antibody (IgM), which was raised against the human tumor cell line, was evaluated for radioimmunodetection of human pancreatic tumors (PAN-5-JCK and EXP-58) grown in nude mice. 125I-labeled DU-PAN II was accumulated into PAN-5-JCK producing DU-PAN II antigen with a tumor-to-blood ratio of 2.72 +/- 3.00, but it did not localize in EXP-58 because of insufficient DU-PAN II. There was no significant uptake of 125I-nonimmunized IgM in PAN-5-JCK. These facts indicated the specific tumor uptake of DU-PAN II. Excellent images of the tumor PAN-5-JCK were obtained 3 days after the injection of 125I-DU-PAN II. Gel chromatography was also investigated with respect to the plasma taken from mice injected with antibody, or incubated with antibody in vitro. The results indicate that circulating antigen affected the tumor uptake of DU-PAN II: The more the tumor grew, the higher the amount of antigen excreted into the blood, leading to the degradation of DU-PAN II before it reached the tumor sites. Consequently, the immunoscintigram of the small tumor was remarkably clear. The catabolism and the radiolysis of the labeled IgM injected are critical points in applying immunoscintigraphy. PMID:3275099

  6. JIMAR, PFRP ANNUAL PROGRESS REPORT P.I. Name: Samuel Pooley and Minling Pan

    E-print Network

    Hawai'i at Manoa, University of

    JIMAR, PFRP ANNUAL PROGRESS REPORT FY 2003 P.I. Name: Samuel Pooley and Minling Pan NMFS Honolulu previously produced by the Leung's project (see Pan et al. 1999). Develop a couple of data processors to examine the model's predictability using the 1993 data because the previous study (Pan et al., 1999

  7. HYPERSPECTRAL PAN-SHARPENING: A CONVEX FORMULATION TO IMPOSE PARALLEL LEVEL LINES

    E-print Network

    Weiss, Pierre

    HYPERSPECTRAL PAN-SHARPENING: A CONVEX FORMULATION TO IMPOSE PARALLEL LEVEL LINES Alexis Huck is with is with CNES, Toulouse, France. ABSTRACT In this paper, we address the issue of hyperspectral pan- sharpening and the huge number of unknowns. Index Terms-- hyperspectral, fusion, pan-sharpening, ADMM 1. INTRODUCTION

  8. IMAGE-BASED PAN-TILT CAMERA CONTROL IN A MULTI-CAMERA SURVEILLANCE ENVIRONMENT

    E-print Network

    Davis, Larry

    IMAGE-BASED PAN-TILT CAMERA CONTROL IN A MULTI-CAMERA SURVEILLANCE ENVIRONMENT Ser-Nam Lim, Ahmed the cameras accurately. Each cam- era must be able to pan-tilt such that an object detected in the scene camera is assigned a pan-tilt zero- position. Position of an object detected in one camera is related

  9. PAN: A High-Performance Active Network Node Supporting Multiple Mobile Code Systems

    E-print Network

    PAN: A High-Performance Active Network Node Supporting Multiple Mobile Code Systems Erik Nygren, New York March 27, 1999 http://www.pdos.lcs.mit.edu/~nygren/pan/ Page 1 #12;Active Networks to be dynamically deployed Critical issues: performance, safety, security, resource management, interoperability PAN

  10. Computations Modulo Regular Chains Xin Li, Marc Moreno Maza and Wei Pan

    E-print Network

    Moreno Maza, Marc

    Computations Modulo Regular Chains Xin Li, Marc Moreno Maza and Wei Pan (University of Western Ontario) ISSAC 2009, Seoul July 30, 2009 Xin Li, Marc Moreno Maza and Wei Pan (University of Western) = (2 x - 1) y - 7 - x. Xin Li, Marc Moreno Maza and Wei Pan (University of Western Ontario

  11. Projective Rotations applied to a Pan-Tilt Stereo Head Andreas Ruf Radu Horaud

    E-print Network

    Paris-Sud XI, Université de

    One of the most useful sensors in computer vision is a pan and tilt stereo head. Such a sensorProjective Rotations applied to a Pan-Tilt Stereo Head Andreas Ruf Radu Horaud Andreas.Martin, France Abstract A non-metric pan-tilt stereo-head consists of a weakly calibrated stereo rig mounted

  12. Photodegradation inhibitors for polyacrylonitrile\\/Ag (PAN\\/Ag) films. Annual report

    Microsoft Academic Search

    C. A. Sergides; A. R. Chughtai; D. M. Smith

    1985-01-01

    Three types of UV stabilizers have been investigated for the photostabilization of PAN\\/Ag films. First, the effect of UV-absorber stabilizers, like the hydrohybenzophenone derivatives (UVINUL SERIES, BASF) absorbing UV radiation in the same region as PAN, was studied. Such additives generally had little effect, while in some cases, photodegradation of PAN was enhanced because of photosensitization. Second, the effect of

  13. Contribution of impervious surfaces to urban evaporation

    NASA Astrophysics Data System (ADS)

    Ramamurthy, P.; Bou-Zeid, E.

    2014-04-01

    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.

  14. Molecular Dynamics Simulations of Water Evaporation

    NASA Astrophysics Data System (ADS)

    Wen, Chengyuan; Grest, Gary; Cheng, Shengfeng

    2015-03-01

    The evaporation of water from the liquid/vapor interface is studied via large-scale molecular dynamics simulations for systems of more than a million atoms at 550K and 600K. The TIP4P-2005 water model whose liquid/vapor surface tension is in excellent agreement with experiments is used. Evaporative cooling at the interface is observed from temperature profiles determined from both translational and rotational kinetic energy. During evaporation, the density of water is slightly enhanced near the liquid-vapor interface. The velocity distribution of water molecules in the vapor phase during evaporation at various distances relative to the interface fit a Maxwell-Boltzmann distribution. While our results indicate an imbalance between evaporating and condensing water molecules, local thermal equilibrium is found to hold in addition to mechanical equilibrium. Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.

  15. Calcium and titanium isotopic fractionations during evaporation

    NASA Astrophysics Data System (ADS)

    Zhang, Junjun; Huang, Shichun; Davis, Andrew M.; Dauphas, Nicolas; Hashimoto, Akihiko; Jacobsen, Stein B.

    2014-09-01

    Isotope fractionations associated with high temperature evaporation provide important constraints on the physicochemical processes that affected planetary materials at the birth of the solar system. Previous evaporation experiments have focused on isotopic fractionation of moderately to highly volatile elements. Here, we investigate the isotope fractionation behavior of two highly refractory elements, calcium and titanium, during evaporation of perovskite (CaTiO3) in a vacuum furnace. In our experiments, isotope fractionation during evaporation follows the Rayleigh law, but not the commonly used exponential law, with the dominant evaporating species being Ca(g) and TiO2(g). If isotope fractionations in early solar system materials did follow the Rayleigh law, the common practice of using an exponential fractionation law to correct for mass-dependent fractionation in the study of mass-independent fractionations may introduce significant artificial isotope anomalies.

  16. Fast gas chromotography with luminol detection for measurement of nitrogen dioxide and PANs.

    SciTech Connect

    Gaffney, J. S.; Marley, N. A.; Drayton, P. J.

    1999-09-30

    Fast capillary gas chromatography has been coupled to a luminol-based chemiluminescence detection system for the rapid monitoring of nitrogen dioxide and peroxyacyl nitrates. A first-generation instrument was described recently (Gaffney et al., 1998). This system is capable of monitoring nitrogen dioxide and peroxyacyl nitrates (PANs; to and including the C4 species) with 1-min time resolution. This is an improvement by a factor of five over gas chromatography methods with electron capture detection. In addition, the luminol method is substantially less expensive than laser fluorescent detection or mass spectroscopic methods. Applications in aircraft-based research have been published electronically and will appear shortly in Environmental Science and Technology (Gaffney et al., 1999a). An improved version of the instrument that has been designed and built makes use of a Hammamatsu photon-counting system. Detection limits of this instrumentation are at the low tens of ppt. The range of the instrument can be adjusted by modifying sampling volumes and detection counting times. A review of past work and of recent application of the instrumentation to field measurements of nitrogen dioxide and PANs is presented. The data clearly indicate that the luminol approach can determine the target species with time resolution of less than 1 min. Examples of applications for estimation of peroxyacetyl radical concentrations and nitrate radical formation rates are also presented. This instrumentation can further be used for evaluation of surfaces for loss of nitrogen dioxide and PANs, phenomena of possible importance for sampling interfaces and chamber wall design. Our high-frequency field data clearly indicate that the ''real world'' is not well mixed and that turbulent mixing and plume-edge chemistries might play an important role in urban- and regional-scale interactions. Dynamic flow systems might be required to evaluate such effects in new-generation chamber studies.

  17. Model Estimates of Pan-Arctic Lake and Wetland Methane Emissions

    NASA Astrophysics Data System (ADS)

    Chen, X.; Bohn, T. J.; Glagolev, M.; Maksyutov, S.; Lettenmaier, D. P.

    2012-12-01

    Lakes and wetlands are important sources of the greenhouse gases CO2 and CH4, whose emission rates are sensitive to climate. The northern high latitudes, which are especially susceptible to climate change, contain about 50% of the world's lakes and wetlands. With the predicted changes in the regional climate for this area within the next century, there is concern about a possible positive feedback resulting from greenhouse gas emissions (especially of methane) from the region's wetlands and lakes. To study the climate response to emissions from northern hemisphere lakes and wetlands, we have coupled a large-scale hydrology and carbon cycling model (University of Washington's Variable Infiltration Capacity model; VIC) with the atmospheric chemistry and transport model (CTM) of Japan's National Institute for Environmental Studies and have applied this modelling framework over the Pan-Arctic region. In particular, the VIC model simulates the land surface hydrology and carbon cycling across a dynamic lake-wetland continuum. The model includes a distributed wetland water table that accounts for microtopography and simulates variations in inundated area that are calibrated to match a passive microwave based inundation product. Per-unit-area carbon uptake and methane emissions have been calibrated using extensive in situ observations. In this paper, the atmospheric methane concentrations from a coupled run of VIC and CTM are calibrated and verified for the Pan-Arctic region with satellite observations from Aqua's Atmospheric Infrared Sounder (AIRS) and Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) instruments. We examine relative emissions from lakes and wetlands, as well as their net greenhouse warming potential, over the last half-century across the Pan-Arctic domain. We also assess relative uncertainties in emissions from each of the sources.

  18. Determination of the Evaporation Coefficient of D2O

    SciTech Connect

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

    2008-03-26

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

  19. Evaporative spray cooling of plain and microporous coated surfaces.

    SciTech Connect

    Kim, J. H.; You, S. M.; Choi, S. U.-S.; Energy Technology; Univ. of Texas at Arlington

    2004-07-01

    Experiments were performed on air and evaporative spray cooling of plain and microporous coated surfaces on flat and cylindrical heaters. Micron-size aluminum particles were used to build the microporous structures on the heated surfaces. To analyze the evaporative cooling, heat transfer curves were obtained in the form of the wall temperature difference versus heat flux. The heat transfer coefficients were also determined as a function of heat flux. Three water flow rates (1.25, 1.75 and 2.40 ml/min) were tested for the flat heater and one rate (3.0 ml/min) for the cylindrical heater, maintaining the air pressure of 7 psig (48 kPa) at the inlet of the nozzle. The effect of different particle sizes in the coating was also tested to optimize the microporous coating technique. Spraying water droplets on the microporous coating surface enhanced the heat removal due to the capillary pumping phenomenon through the microporous cavities connecting each other. The evaporative spray cooling increased the heat transfer coefficient by up to 400% relative to that of the uncoated surface cooled by dry air, and this enhancement was maintained at high heat fluxes by using microporous surfaces.

  20. Measurement of an Evaporating Drop on a Reflective Substrate

    NASA Technical Reports Server (NTRS)

    Chao, David F.; Zhang, Nengli

    2004-01-01

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

  1. Special processing of Apollo 16 Pan Camera film

    Microsoft Academic Search

    M. S. Weinstein

    1972-01-01

    Due to the exposure conditions of the Apollo 16 Pan Camera imagery, a series of tests were run to determine if it was possible to: (1) maintain toe speed to preserve the normally exposed near-terminator imagery, and (2) retain an acceptable density range for the two stop overexposed portion of the imagery. A set of processing conditions (80 F, 15

  2. Pan-American Health Organization CD-ROM Pilot Project.

    ERIC Educational Resources Information Center

    Brito, Claudio J.

    1987-01-01

    Examines the difficulties faced by the implementors of information dissemination systems in developing nations and explores the possible use of optical data disk technologies to overcome them. A pilot project of the Pan American Health Organization for the production of a CD-ROM containing bibliographic references on public health is described.…

  3. 48Pan's Highway -Saturn's Rings The Encke Gap is a

    E-print Network

    48Pan's Highway - Saturn's Rings The Encke Gap is a prominent feature of Saturn's outer A 12 hours as it orbits Saturn! Problem 1 - This image was taken by Cassini in 2007 ring bands are about 0.1 mm wide, which is about 4 km. NASA/Cassini mages, top to bottom: Saturn Rings

  4. Maya Education and Pan Maya Ideology in the Yucatan.

    ERIC Educational Resources Information Center

    Burns, Allan

    1998-01-01

    A University of Yucatan (Mexico) professor who taught a Mayan linguistics course to indigenous teachers in Mayan discusses three issues that are central to understanding how indigenous education interacts with pan-Maya identity: the importance of locally developed Maya literature, the symbols used to define Maya culture, and a conflict over Maya…

  5. A fast variational fusion approach for pan-sharpening

    Microsoft Academic Search

    Ze-ming Zhou; Yuan-xiang Li; Han-qing Shi; Ning Ma; Chun He; Peng Zhang

    2010-01-01

    A fast variational fusion model based on partial differential equation (PDE) is presented for pan-sharpening. The functional is constructed with several energy terms. The gradient energy term is created by calculating the gradient vector field of the panchromatic image. The visualization energy term is used for improving the perceptual effect and the spectral preserving energy term is designed for enforcing

  6. Anomaly Based Web Phishing Page Detection Ying Pan, Xuhua Ding

    E-print Network

    Ding, Xuhua

    Anomaly Based Web Phishing Page Detection Ying Pan, Xuhua Ding School of Information Systems, Singapore Management University {ypan,xhding}@smu.edu.sg Abstract Many anti-phishing schemes have recently been pro- posed in literature. Despite all those efforts, the threat of phishing attacks

  7. Simulating the Pan. inian System of Sanskrit Grammar Anand Mishra

    E-print Network

    Boyer, Edmond

    Simulating the P¯an. inian System of Sanskrit Grammar Anand Mishra Department of Computational Linguistics Ruprecht Karls University, Heidelberg http://sanskrit.sai.uni-heidelberg.de Abstract We propose a model for the computer representation of the P¯an.inian system of sanskrit grammar. Based on this model

  8. Anisotropic electrical conductivity of MWCNT\\/PAN nanofiber paper

    Microsoft Academic Search

    Eun Ju Ra; Kay Hyeok An; Ki Kang Kim; Seung Yol Jeong; Young Hee Lee

    2005-01-01

    The electrospinning process has been used successfully to fabricate the multiwalled carbon nanotubes (MWCNTs)-embedded polyacrylonitrile (PAN) nanofiber paper. The diameters of nanofibers decreased with increasing CNT concentration. We found large anisotropic electrical conductivity, i.e., the electrical conductivity of the carbonized nanofiber paper along the spinning direction was about three times larger than that normal to the spinning direction, in good

  9. Relating Taxonomies with Regulations Chin Pang Cheng, Jiayi Pan

    E-print Network

    Stanford University

    Relating Taxonomies with Regulations Chin Pang Cheng, Jiayi Pan Stanford University Dept. of Civil government regulations and codes of practices, which are not always known to the industry practitioners. Although regulations and codes are now in digital forms and are often available online, it remains

  10. Enhancement of PANS model's performance by introducing advanced numerical techniques

    NASA Astrophysics Data System (ADS)

    Basara, Branislav

    2008-11-01

    The Partially-Averaged Navier-Stokes (PANS) approach is a recently proposed method by Girimaji (2003), which changes seamlessly from RANS to the direct numerical solution of the Navier-Stokes equations (DNS) as the unresolved-to-total ratios of kinetic energy and dissipation are varied. The parameter which determines the unresolved-to-total kinetic energy ratio fk is defined based on the grid spacing. The PANS asymptotic behaviour goes smoothly from RANS to DNS with decreasing fk. In the work of Basara, Krajnovic and Girimaji (2008), it was shown that a dynamic update of the PANS key parameter fk by changing at each point and at the end of every time step is the promising approach to provide the optimum modeling on employed computational meshes. This work is extended here by introducing numerical techniques which efficiently increase a grid resolution and with that, decrease the parameter fk. This is achieved by employment of the effective non-reflecting boundary conditions and cutting computational domains, and by adaptive grids which allow keeping in advance prescribed value of the parameter fk. The results will show benefits of using the advanced numerical techniques in conjunction with PANS method.

  11. 40 CFR 1060.605 - Exemptions from evaporative emission standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...evaporative emission standards based on the model year of the engine...Evaporative emission standards generally apply based on the model year of the equipment...evaporative emission standards based on the model year of the...

  12. Marangoni Effects on Evaporative Lithographic Patterning of Colloidal Films

    E-print Network

    Lewis, Jennifer

    to Marangoni stresses.28 Evaporative cooling andinefficientheattransferthroughthedropinducesatemperatureMarangoni Effects on Evaporative Lithographic Patterning of Colloidal Films Daniel J. Harris 12, 2008 We investigate the effects of Marangoni stresses on the evaporative lithographic patterning

  13. Nanoparticle agglomeration in an evaporating levitated droplet for different acoustic amplitudes

    NASA Astrophysics Data System (ADS)

    Tijerino, Erick; Basu, Saptarshi; Kumar, Ranganathan

    2013-01-01

    Radiatively heated levitated functional droplets with nanosilica suspensions exhibit three distinct stages namely pure evaporation, agglomeration, and finally structure formation. The temporal history of the droplet surface temperature shows two inflection points. One inflection point corresponds to a local maximum and demarcates the end of transient heating of the droplet and domination of vaporization. The second inflection point is a local minimum and indicates slowing down of the evaporation rate due to surface accumulation of nanoparticles. Morphology and final precipitation structures of levitated droplets are due to competing mechanisms of particle agglomeration, evaporation, and shape deformation. In this work, we provide a detailed analysis for each process and propose two important timescales for evaporation and agglomeration that determine the final diameter of the structure formed. It is seen that both agglomeration and evaporation timescales are similar functions of acoustic amplitude (sound pressure level), droplet size, viscosity, and density. However, we show that while the agglomeration timescale decreases with initial particle concentration, the evaporation timescale shows the opposite trend. The final normalized diameter can be shown to be dependent solely on the ratio of agglomeration to evaporation timescales for all concentrations and acoustic amplitudes. The structures also exhibit various aspect ratios (bowls, rings, spheroids) which depend on the ratio of the deformation timescale (tdef) and the agglomeration timescale (tg). For tdef

  14. An Intercomparison of Airborne VOC and PAN Measurements

    NASA Astrophysics Data System (ADS)

    Hansel, A.; Wisthaler, A.; Flocke, F.; Weinheimer, A.; Fall, R.; Goldan, P.; Hübler, G.; Fehsenfeld, F. C.

    2002-12-01

    As part of the Texas Air Quality Study (TexAQS 2000) an informal airborne intercomparison has been conducted to evaluate the state-of-the-art of fast-response, in-situ methods for analyzing Volatile Organic Compounds (VOCs) and peroxyacetyl nitrate (PAN). Instrumentation included a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS), the Tropospheric Airborne Chromatograph for Oxy-hydrocarbons and Hydrocarbons (TACOH) and a gas chromatograph for PAN detection using electron capture (GC/ECD). The measurements were made in the Greater Houston area and East Texas in August/September 2000 during 13 flights with the NSF/NCAR ELECTRA aircraft. The intercomparison was conducted mainly in the boundary layer but included some encounters with air masses from the free troposphere. Final results from the intercomparison show that measurements of acetaldehyde, isoprene, the sum\\textsuperscript{*} of acetone and propanal, the sum\\textsuperscript{*} methyl vinyl ketone and methacrolein (\\textsuperscript{*} PTR-MS does not distinguish between isobaric species) and toluene agree very well. Poor agreement was achieved in the case of methanol and the underlying sensitivity problem in the PTR-MS or TACOH system is under investigation. The results of the PAN intercomparison indicate that the PTR-MS technique suffered from an interference most likely associated with the presence of peracetic acid in photochemically aged air. If this interfering signal was traced by periodically inserting a selective PAN scrubber (thermal decomposition) into the sample air stream and subtracted from the original signal, the corrected PTR-MS PAN data are in very good agreement with the GC/ECD results.

  15. Experiments and numerical modeling to estimate the coating variability in a pan coater.

    PubMed

    Sahni, Ekneet; Chaudhuri, Bodhisattwa

    2011-10-14

    The purpose of this work is to investigate the effect of the coating process parameters on coating performance and coating variability, and hence determine the optimal operating conditions. Coating of particles is done to mask the unpleasant taste or odor of the drug, to control the bioavailability of the API, and to increase shelf-life. The coating solution is sprayed in specific locations of the granular bed and coating uniformity is achieved by interparticle collisions and overall mixing behavior in the coater. Thus, good understanding of particle flow and granular mixing in a pan coater is vital to optimize the process parameters to reduce coating variability. Coating experiments are performed at previously determined optimal mixing conditions using Lactose nonpareils. The coating fluid (aqueous solution of Opadry II) is sprayed intermittently at different flow rates and concentration. Vernier Caliper is used to measure the change in diameter and the coating of the particles. Moreover, DEM based numerical modeling of spray coating is also performed for same operational parameter set and spray characteristic (center and the radius of the spray zone) used in the experiments. DEM simulation provides the residence time distribution of all the particles passing through the spray zone. The coating variability in the experiments is estimated at different pan and spray variables. The coating variability decreases with the increase inpan tilt, coating time and an optimum speed. The spray characteristics does not seem to have much effect on the variability although better coating is observed under better mixing conditions of high tilt and pan speed for the same spray parameters. The mass distribution of coated particles is quantified in the numerical model by the total number of particles passing through the spray zone and also by the frequency distribution of the residence time of the coated particles. It is observed that the simulations are in good agreement with the experiments for the effect of orientation (tilt) of the pan coater on coating variability. However simulations over predicted the effect of speed as compared to the experiments to reach the minimum coating variability. In the current study, the experimental setup did not reflect the typical bead coating setup used in the industry; rather depict a simplified setup to validate the numerical model. PMID:21627984

  16. Adsorption Isotherms for Xenon and Krypton using INL HZ-PAN and AgZ-PAN Sorbents

    SciTech Connect

    Troy G. Garn; Mitchell Greenhalgh; Veronica J. Rutledge; Jack D. Law

    2014-08-01

    The generation of adsorption isotherms compliments the scale-up of off-gas processes used to control the emission of encapsulated radioactive volatile fission and activation products released during Used Nuclear Fuel (UNF) reprocessing activities. A series of experiments were conducted to obtain capacity results for varying Kr and Xe gas concentrations using HZ-PAN and AgZ-PAN engineered form sorbents. Gas compositions for Kr ranged from 150-40,000 ppmv and 250-5020 ppmv for Xe in a helium balance. The experiments were all performed at 220 K at a flowrate of 50 sccm. Acquired capacities were then respectively fit to the Langmuir equation using the Langmuir linear regression method to obtain the equilibrium parameters Qmax and Keq. Generated experimental adsorption isotherms were then plotted with the Langmuir predicted isotherms to illustrate agreement between the two. The Langmuir parameters were provided for input into the OSPREY model to predict breakthrough of single component adsorption of Kr and Xe on HZ-PAN and AgZ-PAN sorbents at the experimental conditions tested. Kr and Xe capacities resulting from model breakthrough predictions were then compared to experimental capacities for model validation.

  17. Stochastic modelling of evaporation based on copulas

    NASA Astrophysics Data System (ADS)

    Pham, Minh Tu; Vernieuwe, Hilde; De Baets, Bernard; Verhoest, Niko

    2015-04-01

    Evapotranspiration is an important process in the water cycle that represents a considerable amount of moisture lost through evaporation from the soil surface and transpiration from plants in a watershed. Therefore, an accurate estimate of evapotranspiration rates is necessary, along with precipitation data, for running hydrological models. Often, daily reference evapotranspiration is modelled based on the Penman, Priestley-Taylor or Hargraeves equation. However, each of these models requires extensive input data, such as daily mean temperature, wind speed, relative humidity and solar radiation. Yet, in design studies, such data is unavailable in case stochastically generated time series of precipitation are used to force a hydrologic model. In the latter case, an alternative model approach is needed that allows for generating evapotranspiration data that are consistent with the accompanying precipitation data. This contribution presents such an approach in which the statistical dependence between evapotranspiration, temperature and precipitation is described by three- and four-dimensional vine copulas. Based on a case study of 72 years of evapotranspiration, temperature and precipitation data, observed in Uccle, Belgium, it was found that canonical vine copulas (C-Vines) in which bivariate Frank copulas are employed perform very well in preserving the dependencies between variables. While 4-dimensional C-Vine copulas performed best in simulating time series of evapotranspiration, a 3-dimensional C-Vine copula (relating evapotranspiration, daily precipitation depth and temperature) still allows for modelling evapotranspiration, though with larger error statistics.

  18. Influence of Oil on Refrigerant Evaporator Performance

    NASA Astrophysics Data System (ADS)

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

    In vapor compression refrigeration system using oil-lubricated compressors, some amount of oil is always circulated through the system. Oil circulation can have a significant influence on the evaporator performance of automotive air conditioner which is especially required to cool quickly the car interior after a period standing in the sun. An experimental investigation was carried out an electrically heated horizontal tube to measure local heat transfer coefficients for various flow rates and heat fluxes during forced convection boiling of pure refrigerant R12 and refrigerant-oil mixtures (0-11% oil concentration by weight) and the results were compared with oil free performance. Local heat transfer coefficients increased at the region of low vapor quality by the addition of oil. On the other hand, because the oil-rich liquid film was formed on the heat transfer surface, heat transfer coefficients gradually decreased as the vapor quality became higher. Average heat transfer coefficient reached a maximum at about 4% oil concentration and this trend agreed well with the results of Green and Furse. Previous correlations, using the properties of the refrigerant-oil mixture, could not predict satisfactorily the local heat transfer coefficients data. New correlation modified by oil concentration factor was developed for predicting the corresponding heat transfer coefficient for refrigerant-oil mixture convection boiling. The maximum percent deviation between predicted and measured heat transfer coefficient was within ±30%.

  19. Developing a CFD-based Approach to Estimate Evaporation from Water Surfaces in (Semi-) Arid Regions

    NASA Astrophysics Data System (ADS)

    Abbasi, Ali; Annor, Frank; van de Giesen, Nick

    2015-04-01

    In arid and semi-arid regions where evaporation highly exceeds rainfall, approximately one half of the stored water in shallow lakes may be lost due to evaporation. Precisely estimating this for very shallow lakes is however a daunting tasks due to the complexity of lake thermodynamics and the interactions between the water surface and air. Evaporation in water is largely uncoupled from land based evapotranspiration and most methods used are case-specific equations which are usually not applicable for other lakes. In this study a Computational Fluid Dynamics(CFD) Evaporation Model is established to adequately quantify the evaporation losses by simulating the air flow and heat transfer in the atmospheric boundary layer. Consideration of the air flow and heat transfer is required to simulate the fetch effect. This model will help to understand the complexities involved in open water evaporation and consequently will lead to more accurate estimates and better strategies for managing and controlling the evaporative loss of fresh water in arid and semi-arid regions. The proposed approach is used to drive a convective mass-transfer coefficient (wind function) required for estimating evaporation of water bodies with the mass-transfer method. The model was applied for a small shallow (with a surface area of 45 hectares and 3m deep on the average) artificial lake in Ghana called Binaba. The heat and mass transfer coefficient over the water surface and their distributions were extracted from the CFD analysis. The results showed that the CFD-derived wind functions were very similar to those empirically derived from the measurements over the lake using Eddy Covariance(EC) System. The evaporation rates calculated with the synthetic wind functions were in good agreement with hourly and daily evaporation measurements for the lake. The established CFD-model is generalizable and cost effective, since it needs low input data. Besides, the model is able to provide additional parameters such as the spatial distribution of the evaporation rate over the water surface. The application of CFD to estimate water bodies evaporation looks very promising.

  20. 242-A evaporator safety analysis report

    SciTech Connect

    CAMPBELL, T.A.

    1999-05-17

    This report provides a revised safety analysis for the upgraded 242-A Evaporator (the Evaporator). This safety analysis report (SAR) supports the operation of the Evaporator following life extension upgrades and other facility and operations upgrades (e.g., Project B-534) that were undertaken to enhance the capabilities of the Evaporator. The Evaporator has been classified as a moderate-hazard facility (Johnson 1990). The information contained in this SAR is based on information provided by 242-A Evaporator Operations, Westinghouse Hanford Company, site maintenance and operations contractor from June 1987 to October 1996, and the existing operating contractor, Waste Management Hanford (WMH) policies. Where appropriate, a discussion address the US Department of Energy (DOE) Orders applicable to a topic is provided. Operation of the facility will be compared to the operating contractor procedures using appropriate audits and appraisals. The following subsections provide introductory and background information, including a general description of the Evaporator facility and process, a description of the scope of this SAR revision,a nd a description of the basic changes made to the original SAR.

  1. Pan-Genomic Analysis Provides Insights into the Genomic Variation and Evolution of Salmonella Paratyphi A

    PubMed Central

    Chen, Chunxia; Cui, Xiaoying; Yu, Jun; Xiao, Jingfa; Kan, Biao

    2012-01-01

    Salmonella Paratyphi A (S. Paratyphi A) is a highly adapted, human-specific pathogen that causes paratyphoid fever. Cases of paratyphoid fever have recently been increasing, and the disease is becoming a major public health concern, especially in Eastern and Southern Asia. To investigate the genomic variation and evolution of S. Paratyphi A, a pan-genomic analysis was performed on five newly sequenced S. Paratyphi A strains and two other reference strains. A whole genome comparison revealed that the seven genomes are collinear and that their organization is highly conserved. The high rate of substitutions in part of the core genome indicates that there are frequent homologous recombination events. Based on the changes in the pan-genome size and cluster number (both in the core functional genes and core pseudogenes), it can be inferred that the sharply increasing number of pseudogene clusters may have strong correlation with the inactivation of functional genes, and indicates that the S. Paratyphi A genome is being degraded. PMID:23028950

  2. Enhanced Evaporation and Condensation in Tubes

    NASA Astrophysics Data System (ADS)

    Honda, Hiroshi

    A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

  3. PII S0016-7037(01)00731-1 Formation of refractory inclusions by evaporation of condensate precursors

    E-print Network

    Grossman, Lawrence

    crystals, is directly proportional to evaporation rate, which is a sensitive function of PH2 solidified under an oxygen fugacity equal to that of a hydrogen-rich gas of solar composition (Beckett, 1986

  4. Effects of surface roughness on evaporation from porous surfaces into turbulent airflows

    NASA Astrophysics Data System (ADS)

    Haghighi, Erfan; Or, Dani

    2014-05-01

    The ubiquitous and energy intensive mass transfer between wet porous surfaces and turbulent airflows is of great importance for various natural and industrial applications. The roughness of natural surfaces is likely to influence the structure of adjacent boundary layer and thus affecting heat and mass fluxes from surfaces. These links were formalized in a new model that considers the intermittent turbulence-induced boundary layer with local mass and energy exchange rates. We conducted experiments with regular surface roughness patterns subjected to constant turbulent airflows and monitored mass loss and thermal signatures of localized evaporative fluxes using infrared thermography. The resulting patterns were in good agreement with model predictions for local and surface averaged turbulent exchange rates. Preliminary results obtained for evaporation from sinusoidal wavy soil surfaces reveal that evaporative fluxes can be either enhanced or suppressed (relative to a flat surface) owing to relative contribution of downstream (separation zone) and rising (reattachment zone) surfaces of the wave with thick and thin viscous sublayer thicknesses, respectively. For isolated roughness elements (bluff bodies) over a flat evaporating surface, the resulting fluxes are enhanced (relative to a smooth surface) due to formation of vortices that induce thinner boundary layer. Potential benefits of the study for interpretation and upscaling of evaporative and heat fluxes from natural (rough) terrestrial surfaces will be discussed. Keywords: Turbulent Evaporation, Porous Media, Surface Roughness, Infrared Thermography.

  5. Temperature dependence of the vapor pressure and evaporation coefficient of supercooled water

    NASA Astrophysics Data System (ADS)

    Davies, James F.; Miles, Rachael E. H.; Haddrell, Allen E.; Reid, Jonathan P.

    2014-09-01

    We report measurements of the vapor pressure of water over the supercooled temperature range 248 to 273 K derived from evaporation kinetics measurements of single water droplets. Accurate measurements of the relative humidity of the surrounding gas phase are derived from comparative and sequential measurements of the evaporation kinetics of droplets containing sodium chloride. The temperature dependence of the vapor pressure of supercooled water is shown to conform closely to the parameterization provided by Murphy and Koop (2005) once the uncertainties in experimental and thermophysical parameters are accounted for by ensuring an accurate representation of evaporation rates at temperatures above 273 K. Further, from a sensitivity analysis of all of the data over the full temperature range from 248 to 293 K, we can conclude that the evaporation coefficient of water, and thus the mass accommodation coefficient, is greater than, or equal to, 0.5.

  6. Pan-private Algorithms Via Statistics on Sketches Darakhshan Mir, S. Muthukrishnan, Aleksandar Nikolov, Rebecca N. Wright

    E-print Network

    Wright, Rebecca N.

    Pan-private Algorithms Via Statistics on Sketches Darakhshan Mir, S. Muthukrishnan, Aleksandar together with security, formulated recently as pan-privacy by Dwork et al. (ICS 2010). Informally, pan or law). We study pan-private algorithms for basic analyses, like estimating distinct count, moments

  7. Afring News online 38:24-27, 2009 A decade of tern ringing at Mile 4 salt pans, Namibia

    E-print Network

    de Villiers, Marienne

    24 Afring News online 38:24-27, 2009 A decade of tern ringing at Mile 4 salt pans, Namibia Mark Boorman felix@mweb.com.na The Mile 4 Salt Pans are a series of man-made pans created for the harvesting of salt for human consumption, situated just north of Swakopmund. These pans host resident birds, intra

  8. Aurlie Helmlinger, Pan Jumbie. Mmoire sociale et musicale dans les steelbands (Trinidad et Tobago), Nanterre, Socit d'ethnologie, 2012,

    E-print Network

    Paris-Sud XI, Université de

    Aurélie Helmlinger, Pan Jumbie. Mémoire sociale et musicale dans les steelbands (Trinidad et Tobago pan1 dans un orchestre de steelband2 . Comme toutes des pratiques musicales, jouer du pan à Trinidad britannique, puis érigée peu à peu en emblème national à partir de l'indépendance du pays, la pratique du pan

  9. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, SUBMITTED DECEMBER 19, 2008 1 Variational Wavelet Pan-Sharpening

    E-print Network

    Soatto, Stefano

    Wavelet Pan-Sharpening Michael Moeller, Todd Wittman, Andrea L. Bertozzi Abstract--Pan to obtain a high resolution multispectral image. We propose a new pan-sharpening method called Variational Wavelet Pan-sharpening (VWP) that combines wavelet fusion and the edges of the panchromatic image

  10. Turbulent transition of thermocapillary flow induced by water evaporation

    NASA Astrophysics Data System (ADS)

    Ward, C. A.; Duan, Fei

    2004-05-01

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

  11. Simultaneous ion and neutral evaporation in aqueous nanodrops: experiment, theory, and molecular dynamics simulations.

    PubMed

    Higashi, Hidenori; Tokumi, Takuya; Hogan, Christopher J; Suda, Hiroshi; Seto, Takafumi; Otani, Yoshio

    2015-06-28

    We use a combination of tandem ion mobility spectrometry (IMS-IMS, with differential mobility analyzers), molecular dynamics (MD) simulations, and analytical models to examine both neutral solvent (H2O) and ion (solvated Na(+)) evaporation from aqueous sodium chloride nanodrops. For experiments, nanodrops were produced via electrospray ionization (ESI) of an aqueous sodium chloride solution. Two nanodrops were examined in MD simulations: a 2500 water molecule nanodrop with 68 Na(+) and 60 Cl(-) ions (an initial net charge of z = +8), and (2) a 1000 water molecule nanodrop with 65 Na(+) and 60 Cl(-) ions (an initial net charge of z = +5). Specifically, we used MD simulations to examine the validity of a model for the neutral evaporation rate incorporating both the Kelvin (surface curvature) and Thomson (electrostatic) influences, while both MD simulations and experimental measurements were compared to predictions of the ion evaporation rate equation of Labowsky et al. [Anal. Chim. Acta, 2000, 406, 105-118]. Within a single fit parameter, we find excellent agreement between simulated and modeled neutral evaporation rates for nanodrops with solute volume fractions below 0.30. Similarly, MD simulation inferred ion evaporation rates are in excellent agreement with predictions based on the Labowsky et al. equation. Measurements of the sizes and charge states of ESI generated NaCl clusters suggest that the charge states of these clusters are governed by ion evaporation, however, ion evaporation appears to have occurred with lower activation energies in experiments than was anticipated based on analytical calculations as well as MD simulations. Several possible reasons for this discrepancy are discussed. PMID:26013735

  12. A Comparison of EPIcode and ALOHA Calculations for Pool Evaporation and Chemical Atmospheric Transport and Dispersion.

    SciTech Connect

    Andrew, VINCENT

    2005-04-22

    EPIcode (version 7.0) and ALOHA (version 5.2.3) are two of the designated toolbox codes identified in the Department of Energy's Implementation Plan for DNFSB Recommendation 2002-1 on Software Quality Assurance issues in the DOE Complex. Both have the capability to estimate evaporation rates from pools formed from chemical spills and to predict subsequent atmospheric transport and dispersion. This paper provides an overview of the algorithms used by EPIcode and ALOHA to calculate evaporation rates and downwind plume concentrations. The technical bases for these algorithms are briefly discussed, and differences in the EPIcode and ALOHA methodologies highlighted. In addition, sample calculations are performed using EPIcode and ALOHA for selected chemicals under various environmental conditions. Side-by-side comparisons of results from sample calculations are analyzed to illustrate the impact that the different methodologies used by EPIcode and ALOHA have on predicted evaporation rates and downwind concentrations.

  13. 21 CFR 131.130 - Evaporated milk.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...total milk solids. Evaporated milk contains added vitamin D as prescribed by paragraph (b) of this section...after sealing, as to prevent spoilage. (b) Vitamin addition. (1) Vitamin D shall be present in such quantity that...

  14. Conductive Thermal Interaction in Evaporative Cooling Process 

    E-print Network

    Kim, B. S.; Degelman, L. O.

    1990-01-01

    between water and entering air for thermal comfort. This hybrid system outperforms the two-stage evaporative cooler without employing a complicated heat exchanger (indirect system), if the temperature of underground water is lower than the ambient wet...

  15. Generalized Quantum Theory and Black Hole Evaporation

    E-print Network

    James B. Hartle

    1998-08-26

    Usually quantum theory is formulated in terms of the evolution of states through spacelike surfaces. However, a generalization of this formulation is needed for field theory in spacetimes not foliable by spacelike surfaces, or in quantum gravity where geometry is not definite but a quantum variable. In particular, a generalization of usual quantum theory is needed for field theory in the spacetimes that model the process of black hole evaporation. This paper discusses a spacetime generalization of usual quantum theory that is applicable to evaporating black hole spacetimes. In this generalization, information is not lost in the process of evaporation. Rather, complete information is distributed about four-dimensional spacetime. Black hole evaporation is thus not in conflict with the principles of quantum theory when suitably generally stated. (Talk presented at the 49th Yamada Conference: Black Holes and High Energy Astrophysics, Kyoto Japan, April 7-10, 1998.)

  16. New Directions for Evaporative Cooling Systems.

    ERIC Educational Resources Information Center

    Robison, Rita

    1981-01-01

    New energy saving technology can be applied to older cooling towers; in addition, evaporative chilling, a process that links a cooling tower to the chilling equipment, can reduce energy use by 80 percent. (Author/MLF)

  17. Heavy quark production in the black hole evaporation at LHC

    SciTech Connect

    Thiel, M.; Goncalves, V. P.; Sauter, W. K. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas (Brazil)

    2013-03-25

    The understanding of Quantum Chromodynamics (QCD) and Quantum Gravity are currently two of the main open questions in Physics. In order to understand these problems some authors proposed the existence of extra dimensions in the Nature. These extra dimensions would be compacted and not visible on the macroscopic world, but the effects would be manifest in ultrarelativistic colision process. In particular, black holes (BH) could be produced in proton-proton colisions in the Large Hadron Collider (LHC) and in future colliders. The BH is an object characterized by its mass and temperature wich also characterizes the evaporation process. All kind of particle should be produced in this process. Our goal in this contribution is to study the BH production in proton - proton collisions at LHC and its evaporation rate in heavy quarks. We present our estimate considering two scenarios (with and without trapped energy corrections) and compare our predictions with those obtained using perturbative QCD. Our results demonstrate that in both scenarios the charm and bottom production in the BH evaporation are smaller than the QCD prediction at LHC. In contrast, the top production is similar or larger than the QCD prediction, if the trapped energy corrections are disregarded.

  18. Evaporation loss from storage tanks

    SciTech Connect

    Wagoner, R.B. [Matrix Service, Inc., Tulsa, OK (United States)

    1995-12-01

    The loss of stored hydrocarbons has been a concern since the early days of the petroleum industry. Initially hydrocarbon liquids were stored in open tanks or in tanks with only fixed roof covers. The theory of storage tanks with floating roof was born in 1880. The initial concept was patented by William Birge of Franklin, Pennsylvania. Birge revealed his idea after the U.S.A. Petroleum industry suffered its first major industrial disaster. A tank with stored hydrocarbon liquid was struck directly by lightening. The results were catastrophic. After this incident a concept was revealed to the United States Patent office. The concept was noted as follows: {open_quotes}It is often the case that oil tanks are struck by lightning and when lightning stored beneath the roof is instantly ignited and explodes, the explosion either throwing the roof off from the tank or slivering it into pieces, thus exposing the oil and setting it afire. The result of such an accident is the loss of the tank itself which alone involves the loss of several thousand dollars. The object of my invention is to provide an oil tank such that the surface of oil in the tank will always be covered and protected regardless of the quantity of oil in the tank and no space be provided between the oil and cover for the accumulation of the escaping gases, and with these ends in view, my invention consists essentially, an oil tank with a floating cover{close_quotes}. Various concepts of floating roofs and seals have been presented over the last 100 years. Safety and conservation are still a primary concern for storage of hydrocarbon liquids. Environmental pollution from hydrocarbon emissions has become a major concern for the storage industry. This paper is an attempt to describe these devices and how to quantify the evaporation losses from stationary sources. The stationary losses from external floating roofs will primarily be addressed in this paper.

  19. Evaporative cooling of air in impinging streams

    Microsoft Academic Search

    B. Yao; Y. Berman; A. Tamir

    1995-01-01

    An experimental study was conducted on evaporative cooling of air in an impinging-stream reactor, in which two droplet gas streams flow in opposite directions and meet in the impingement zone. The air was cooled by evaporation of water droplets. Volumetric heat-transfer coefficients h{sub v} determined enabled the authors to evaluate the performance of the cooler. Maximum values of h{sub v}

  20. Modeling Evaporation of Drops of Different Kerosenes

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth

    2007-01-01

    A mathematical model describes the evaporation of drops of a hydrocarbon liquid composed of as many as hundreds of chemical species. The model is intended especially for application to any of several types of kerosenes commonly used as fuels. The concept of continuous thermodynamics, according to which the chemical composition of the evaporating multicomponent liquid is described by use of a probability distribution function (PDF). However, the present model is more generally applicable than is its immediate predecessor.

  1. Acoustic Signature of Evaporation from Porous Media

    NASA Astrophysics Data System (ADS)

    Grapsas, N. K.; Shokri, N.

    2012-12-01

    During evaporation from saturated porous media, rapid interfacial jumps at the pore scale, known as Haines jumps, occur as air invades the pore network and displaces the evaporating fluid. This process produces crackling noises that can be detected using an acoustic emission (AE) machine. In this study, we investigated the acoustic signature of evaporation from porous media using Hele-Shaw cells packed with seven types of sand and glass beads differing in particle size distribution and surface roughness. Each sample was saturated with dyed water, left to evaporate under constant atmospheric conditions on a digital balance in an environmental chamber, and digitally imaged every 20 minutes to quantify phase distribution. An AE sensor was fixed to each column to record the features of observed AE events (hits) such as amplitude, absolute energy, and duration. Results indicate that the cumulative number of hits is strongly related to evaporative mass loss through time in all configurations. Additionally, the cumulative number of hits shares an inverse relationship with particle size and roughness. Finally, image analysis of the liquid phase distribution during evaporation reveals a strong correlation between the area invaded by air and the cumulative AE hits detected in each column. This confirms that AEs are generated by receding liquid menisci and the propagation of drying fronts in porous media. These results suggest that AE techniques may potentially be used to non-invasively analyze the drying of porous media.

  2. Estimating soil water evaporation using radar measurements

    NASA Technical Reports Server (NTRS)

    Sadeghi, Ali M.; Scott, H. D.; Waite, W. P.; Asrar, G.

    1988-01-01

    Field studies were conducted to evaluate the application of radar reflectivity as compared with the shortwave reflectivity (albedo) used in the Idso-Jackson equation for the estimation of daily evaporation under overcast sky and subhumid climatic conditions. Soil water content, water potential, shortwave and radar reflectivity, and soil and air temperatures were monitored during three soil drying cycles. The data from each cycle were used to calculate daily evaporation from the Idso-Jackson equation and from two other standard methods, the modified Penman and plane of zero-flux. All three methods resulted in similar estimates of evaporation under clear sky conditions; however, under overcast sky conditions, evaporation fluxes computed from the Idso-Jackson equation were consistently lower than the other two methods. The shortwave albedo values in the Idso-Jackson equation were then replaced with radar reflectivities and a new set of total daily evaporation fluxes were calculated. This resulted in a significant improvement in computed soil evaporation fluxes from the Idso-Jackson equation, and a better agreement between the three methods under overcast sky conditions.

  3. Lithium Ion Polymer Electrolyte Based on Pva-Pan

    NASA Astrophysics Data System (ADS)

    Genova, F. Kingslin Mary; Selvasekarapandian, S.; Rajeswari, N.; Devi, S. Siva; Karthikeyan, S.; Raja, C. Sanjeevi

    2013-07-01

    The polymer blend electrolytes based on polyvinylalcohol(PVA) and polyacrylonitrile (PAN) doped with lithium per chlorate (LiClO4) have been prepared by solution casting technique using DMF as solvent. The complex formation between blend polymer and the salt has been confirmed by Fourier transform infrared spectroscopy. The amorphous nature of the blend polymer electrolyte has been confirmed by X-ray diffraction analysis. The ionic conductivity of the prepared blend polymer electrolyte has been found by ac impedence spectroscopic analysis. The highest ionic conductivity has been found to be 5.0 X10-4 S cm -1 at room temperature for 92.5 PVA: 7.5PAN: 20 molecular wt. % of LiClO4. The effect of salt concentration on the conductivity of the blend polymer electrolyte has been discussed.

  4. Lens technology incorporating internal pan/tilt and zoom

    NASA Astrophysics Data System (ADS)

    Rana, Harbinder S.

    2008-09-01

    A lens that incorporates an internal optical pan and tilt mechanism using a Risley prism has been designed. A zoom mechanism that provides various ratios up to 10x has also been incorporated. The design of the lens allows any object in the field of view to be brought into the centre of the field and then zoomed onto. The lens design is scalable. The first variant was designed with a focal range of 2-10mm with a pan/tilt of 46° within a field of view of 90° in a pinhole lens configuration. Importantly the lens has an external stationary entrance pupil that leads to a compact form. A technology demonstrator has been built and its performance is discussed. Further developments of the lens technology are also discussed, including a 120° field of view variant with a 10x zoom.

  5. The ExoMars PanCam Instrument

    Microsoft Academic Search

    Andrew Griffiths; Andrew Coates; Jan-Peter Muller; Ralf Jaumann; Jean-Luc Josset; Gerhard Paar; David Barnes

    2010-01-01

    The ExoMars mission has evolved into a joint European-US mission to deliver a trace gas orbiter and a pair of rovers to Mars in 2016 and 2018 respectively. The European rover will carry the Pasteur exobiology payload including the 1.56 kg Panoramic Camera. PanCam will provide multispectral stereo images with 34 deg horizontal field-of-view (580 microrad\\/pixel) Wide-Angle Cameras (WAC) and

  6. Improving Security in the ATLAS PanDA System

    NASA Astrophysics Data System (ADS)

    Caballero, J.; Maeno, T.; Nilsson, P.; Stewart, G.; Potekhin, M.; Wenaus, T.

    2011-12-01

    The security challenges faced by users of the grid are considerably different to those faced in previous environments. The adoption of pilot jobs systems by LHC experiments has mitigated many of the problems associated with the inhomogeneities found on the grid and has greatly improved job reliability; however, pilot jobs systems themselves must then address many security issues, including the execution of multiple users' code under a common 'grid' identity. In this paper we describe the improvements and evolution of the security model in the ATLAS PanDA (Production and Distributed Analysis) system. We describe the security in the PanDA server which is in place to ensure that only authorized members of the VO are allowed to submit work into the system and that jobs are properly audited and monitored. We discuss the security in place between the pilot code itself and the PanDA server, ensuring that only properly authenticated workload is delivered to the pilot for execution. When the code to be executed is from a 'normal' ATLAS user, as opposed to the production system or other privileged actor, then the pilot may use an EGEE developed identity switching tool called gLExec. This changes the grid proxy available to the job and also switches the UNIX user identity to protect the privileges of the pilot code proxy. We describe the problems in using this system and how they are overcome. Finally, we discuss security drills which have been run using PanDA and show how these improved our operational security procedures.

  7. Shelf life estimation of brown pan bread: A consumer approach

    Microsoft Academic Search

    Ana Giménez; Paula Varela; Ana Salvador; Gastón Ares; Susana Fiszman; Lorena Garitta

    2007-01-01

    In this study three different approaches—acceptability limit, failure cut-off point methodology, and survival analysis—to estimate the sensory shelf life of brown pan bread elaborated with different enzymes using consumer data were compared. The study was carried out in Spain and Uruguay independently, where four batches of bread were produced, with the same base formulation, one without enzyme, the others with

  8. PAN AIR summary document (version 1.0)

    NASA Technical Reports Server (NTRS)

    Derbyshire, T.; Sidwell, K. W.

    1982-01-01

    The capabilities and limitations of the panel aerodynamics (PAN AIR) computer program system are summarized. This program uses a higher order panel method to solve boundary value problems involving the Prandtl-Glauert equation for subsonic and supersonic potential flows. Both aerodynamic and hydrodynamic problems can be solved using this modular software which is written for the CDC 6600 and 7600, and the CYBER 170 series computers.

  9. Review of the ALOHA code pool evaporation model

    SciTech Connect

    Kalinich, D.A.

    1995-11-01

    The ALOHA computer code determines the evaporative mass transfer rate from a liquid pool by solving the conservation of mass and energy equations associated with the pool. As part of the solution of the conservation of energy equation, the heat flux from the ground to the pool is calculated. The model used in the ALOHA code is based on the solution of the temperature profile for a one-dimensional semi-infinite slab. This model is only valid for cases in which the boundary condition (pool temperature) is held constant. Thus, when the pool material temperature is not constant, the ALOHA ground-to-pool heat flux calculation may result in a non-conservative evaporation rate. The analytical solution for the temperature profile of a one-dimensional semi-infinite slab with a time-dependent boundary condition requires a priori knowledge of the boundary condition. Lacking such knowledge, a time-dependent finite-difference solution for the ground temperature profile was developed. The temperature gradient, and thus the ground-to-pool heat flux, at the ground-pool interface is determined from the results of the finite-difference solution. The evaporation rates over the conditions sampled using the ALOHA ground-to-pool heat flux model were up to 15% lower than those generated when the finite-difference model to calculate ground-to-pool heat flux. Overall ALOHA code estimates may compensate by judicious selection of input parameters and assumptions. Application to safety analyses thus must be performed cautiously to ensure that estimated chemical source term and its attendant downwind concentrations are bounding.

  10. Global satellite retrievals of Peroxy Acetyl Nitrate (PAN) in the troposphere

    NASA Astrophysics Data System (ADS)

    Payne, V.; Alvarado, M.; Cady-Pereira, K. E.; Worden, J.; Kulawik, S. S.; Fischer, E. V.

    2013-12-01

    Peroxyacetyl Nitrate (PAN) is a thermally unstable reservoir for NOx that allows NOx to be transported over large distances, enabling ozone formation far downwind from the original source. Satellite retrievals of PAN could potentially provide substantial information on the fate of NOx emissions from a range of sources including biomass burning and anthropogenic combustion. PAN has previously been retrieved in the upper troposphere and lower stratosphere on a global scale from limb-sounding satellite instruments. PAN signatures have also been detected in nadir-viewing satellite observations of smoke plumes from fires. However, to our knowledge, PAN has not yet been retrieved in the nadir view on a global scale. Here we present global observations of tropospheric PAN from the Tropospheric Emission Spectrometer (TES), a thermal infrared spectrometer flying on the Aura satellite since 2004. PAN can be detected in TES spectra for cases where the PAN signal is above the instrument noise. The detection limit for a single TES measurement is dependent on the atmospheric and surface conditions. For observations where the cloud optical depth is less than 0.5, we find that the TES detection limit for PAN is in the region of 200 to 300 pptv. We present example distributions of elevated PAN concentrations associated with (1) trans-Pacific transport of Asian pollution, (2) boreal biomass burning and (3) the Tropical South Atlantic in austral spring.

  11. Pan1 regulates transitions between stages of clathrin-mediated endocytosis

    PubMed Central

    Bradford, Mary Katherine; Whitworth, Karen; Wendland, Beverly

    2015-01-01

    Endocytosis is a well-conserved process by which cells invaginate small portions of the plasma membrane to create vesicles containing extracellular and transmembrane cargo proteins. Dozens of proteins and hundreds of specific binding interactions are needed to coordinate and regulate these events. Saccharomyces cerevisiae is a powerful model system with which to study clathrin-mediated endocytosis (CME). Pan1 is believed to be a scaffolding protein due to its interactions with numerous proteins that act throughout the endocytic process. Previous research characterized many Pan1 binding interactions, but due to Pan1's essential nature, the exact mechanisms of Pan1's function in endocytosis have been difficult to define. We created a novel Pan1-degron allele, Pan1-AID, in which Pan1 can be specifically and efficiently degraded in <1 h upon addition of the plant hormone auxin. The loss of Pan1 caused a delay in endocytic progression and weakened connections between the coat/actin machinery and the membrane, leading to arrest in CME. In addition, we determined a critical role for the central region of Pan1 in endocytosis and viability. The regions important for endocytosis and viability can be separated, suggesting that Pan1 may have a distinct role in the cell that is essential for viability. PMID:25631817

  12. Pan1 regulates transitions between stages of clathrin-mediated endocytosis.

    PubMed

    Bradford, Mary Katherine; Whitworth, Karen; Wendland, Beverly

    2015-04-01

    Endocytosis is a well-conserved process by which cells invaginate small portions of the plasma membrane to create vesicles containing extracellular and transmembrane cargo proteins. Dozens of proteins and hundreds of specific binding interactions are needed to coordinate and regulate these events. Saccharomyces cerevisiae is a powerful model system with which to study clathrin-mediated endocytosis (CME). Pan1 is believed to be a scaffolding protein due to its interactions with numerous proteins that act throughout the endocytic process. Previous research characterized many Pan1 binding interactions, but due to Pan1's essential nature, the exact mechanisms of Pan1's function in endocytosis have been difficult to define. We created a novel Pan1-degron allele, Pan1-AID, in which Pan1 can be specifically and efficiently degraded in <1 h upon addition of the plant hormone auxin. The loss of Pan1 caused a delay in endocytic progression and weakened connections between the coat/actin machinery and the membrane, leading to arrest in CME. In addition, we determined a critical role for the central region of Pan1 in endocytosis and viability. The regions important for endocytosis and viability can be separated, suggesting that Pan1 may have a distinct role in the cell that is essential for viability. PMID:25631817

  13. Pan-STARRS, ATLAS and optical transient searches.

    PubMed

    Tonry, J L

    2013-06-13

    The Pan-STARRS1 survey is collecting multi-epoch, multi-colour observations of the sky north of declination -30°, and has designated 70?deg(2) for nightly observations that are particularly useful for transient detection. A duplicate, Pan-STARRS2, is nearing completion that offers opportunities to improve the quality of transient search and observation, as well as simply increasing the number of detections. A new system, the Asteroid Terrestrial-impact Last Alert System (ATLAS), increases the search area to all-sky in return for diminished sensitivity, and highlights tension among optimization for static sky images, optimization for faint transients and optimization for an unbiased number of transients. ATLAS gives up sub-arcsecond images and full colour information to specialize in the third category, but should detect many more transients than the Pan-STARRS1 Medium Deep fields or the Palomar Transient Factory, with examples of transient classes that are considerably closer and brighter. PMID:23630375

  14. Convective heat and mass transfer from single evaporating water, methanol and ethanol droplets

    SciTech Connect

    Yearling, P.R.; Gould, R.D. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering

    1995-12-31

    The experimental measurements of convective heat and mass transfer rates from single evaporating water, methanol and ethanol droplets suspended in a turbulent air flow are considered. This study is a continuation of the work presented by Yearling and Gould (1993). Specifically, this paper considers the effects of Reynolds number, mass transfer number and turbulence intensity of the upstream air on the evaporation rate of liquid droplets. For a turbulence intensity of 5% these measurements show that the Nusselt number increases by up to 30% over that for a laminar flow at the same droplet Reynolds number. At 10% turbulence intensity the Nusselt number increases by up to 50%.

  15. Evaporation kinetics of Mg2SiO4 crystals and melts from molecular dynamics simulations

    NASA Technical Reports Server (NTRS)

    Kubicki, J. D.; Stolper, E. M.

    1993-01-01

    Computer simulations based on the molecular dynamics (MD) technique were used to study the mechanisms and kinetics of free evaporation from crystalline and molten forsterite (i.e., Mg2SiO4) on an atomic level. The interatomic potential employed for these simulations reproduces the energetics of bonding in forsterite and in gas-phase MgO and SiO2 reasonably accurately. Results of the simulation include predicted evaporation rates, diffusion rates, and reaction mechanisms for Mg2SiO4(s or l) yields 2Mg(g) + 20(g) + SiO2(g).

  16. Evaluation of a two-stage evaporation approximation for contrasting vegetation cover

    NASA Astrophysics Data System (ADS)

    Boulet, G.; Chehbouni, A.; Braud, I.; Duchemin, B.; Lakhal, A.

    2004-12-01

    For a regional assessment of water needs and consumption in semiarid agricultural zones, one needs robust and simple tools that provide space-time estimates of evaporation losses. Most operational evaporation estimates rely on semiempirical relationships that are not generally applicable. Several authors have proposed physically based simple expressions to model the "energy-limited" (stage-one) and the "supply-limited" (stage-two) evaporation rates during a dry down. They use the time compression approximation (TCA) to relate stage-one and stage-two drying. Two asymptotic approximations of the TCA corresponding to the diffusion-dominated and the drainage-dominated flows have been proposed in the literature. In this study a full analytical solution of the TCA is presented. The derived "supply-limited" evaporation rate is evaluated for a wide range of soil conditions and vegetation cover against a physically based complex soil-vegetation-atmosphere transfer model, the Simple Soil-Plant-Atmosphere Transfer scheme (SiSPAT). SiSPAT solves the differential equations of water flow in a vertical soil column and computes estimates of soil evaporation and transpiration. SiSPAT is used to evaluate the performance of the full solution as well as the two existing asymptotic approximations for the case of sparse to dense vegetation in a semiarid environment. The full analytical solution gives accurate predictions of first- to second-stage evaporation time series for the bare soil and vegetated cover conditions with a leaf area index of 3 or higher. The results of the full solution are closer to the evaporation rate time series simulated by SISPAT than the asymptotic approximations.

  17. Evaporation Into the Atmosphere: Theory, History, and Applications

    Microsoft Academic Search

    Harvey E. Jobson

    1982-01-01

    Evaporation is a topic that crosses several disciplines, and comprehensive texts on the subject are rare. Evaporation Into the Atmosphere is, therefore, a welcome addition to the literature. The approach to the determination of evaporation varies significantly depending upon the constraints that control the system of interest. The oceanographer, for example, is concerned with evaporation from large bodies of water

  18. A general mathematical model of evaporative cooling devices

    Microsoft Academic Search

    Boris Halasz

    1998-01-01

    In this paper a general nondimensional mathematical model for the description of all types of evaporative cooling devices in today's use (water cooling towers, evaporative condensers and evaporative fluid coolers, air washers, dehumidifying coils etc.) is presented. The system of differential equations describing nonadiabatic evaporation processes is transformed to a pure nondimensional form by the introduction of nondimensional coordinates and

  19. PanOCT: automated clustering of orthologs using conserved gene neighborhood for pan-genomic analysis of bacterial strains and closely related species

    PubMed Central

    Fouts, Derrick E.; Brinkac, Lauren; Beck, Erin; Inman, Jason; Sutton, Granger

    2012-01-01

    Pan-genome ortholog clustering tool (PanOCT) is a tool for pan-genomic analysis of closely related prokaryotic species or strains. PanOCT uses conserved gene neighborhood information to separate recently diverged paralogs into orthologous clusters where homology-only clustering methods cannot. The results from PanOCT and three commonly used graph-based ortholog-finding programs were compared using a set of four publicly available strains of the same bacterial species. All four methods agreed on ?70% of the clusters and ?86% of the proteins. The clusters that did not agree were inspected for evidence of correctness resulting in 85 high-confidence manually curated clusters that were used to compare all four methods. PMID:22904089

  20. Evaporation from a small prairie wetland in the Cottonwood Lake Area, North Dakota - An energy-budget study

    USGS Publications Warehouse

    Parkhurst, R.S.; Winter, T.C.; Rosenberry, D.O.; Sturrock, A.M.

    1998-01-01

    Evaporation from Wetland Pl in the Cottonwood Lake area of North Dakota, USA was determined by the energy-budget method for 1982-85 and 1987. Evaporation rates were as high as 0.672 cm day-1. Incoming solar radiation, incoming atmospheric radiation, and long-wave radiation emitted from the water body are the largest energy fluxes to and from the wetland. Because of the small heat storage of the water body, evaporation rates closely track solar radiation on short time scales. The effect of advected energy related to precipitation is small because the water quickly heats up by solar radiation following precipitation. Advected energy related to ground water is minimal because ground-water fluxes are small and groundwater temperature is only about 7 ??C. Energy flux related to sediment heating and thermal storage in the sediments, which might be expected to be large because the water is clear and shallow, affects evaporation rates by less than 5 percent.