Science.gov

Sample records for pan evaporation rates

  1. Differences in evaporation between a floating pan and class a pan on land

    USGS Publications Warehouse

    Masoner, J.R.; Stannard, D.I.; Christenson, S.C.

    2008-01-01

    Research was conducted to develop a method for obtaining floating pan evaporation rates in a small (less than 10,000 m2) wetland, lagoon, or pond. Floating pan and land pan evaporation data were collected from March 1 to August 31, 2005, at a small natural wetland located in the alluvium of the Canadian River near Norman, Oklahoma, at the U.S. Geological Survey Norman Landfill Toxic Substances Hydrology Research Site. Floating pan evaporation rates were compared with evaporation rates from a nearby standard Class A evaporation pan on land. Floating pan evaporation rates were significantly less than land pan evaporation rates for the entire period and on a monthly basis. Results indicated that the use of a floating evaporation pan in a small free-water surface better simulates actual physical conditions on the water surface that control evaporation. Floating pan to land pan ratios were 0.82 for March, 0.87 for April, 0.85 for May, 0.85 for June, 0.79 for July, and 0.69 for August. ?? 2008 American Water Resources Association.

  2. Wind-induced splash in Class A evaporation pan

    NASA Astrophysics Data System (ADS)

    Chu, Chia-Ren; Li, Ming-Hsu; Chang, Yu-Feng; Liu, Tsung-Chiang; Chen, Yi-Ying

    2012-06-01

    This study investigates the wind-induced splash in the Class A evaporation pan through a series of wind tunnel experiments. The experimental results revealed that high wind speed can generate seiche wave inside the pan and splash water out of the pan in several minutes. The splash loss increases as the wind speed increases, and the loss rate is at least one order of magnitude greater than the evaporation rate. In other words, the water loss from the pan is not entirely due to evaporation, and the evaporation rates under high wind speeds are over-estimated. By checking the wind speeds and evaporation rates from a four-year (2004-2008) field observation collected in northern Taiwan, it is found that the hourly evaporation rate was unusually high when wind speed was larger than 7 m s-1. The splash-out criterion is set as: hourly average wind speed U ? 7 m s-1 and evaporation rate E > 1.64 mm hr-1. The ratio of the splash-out to the average evaporation rate is 0.75% at this site. In addition, this study examines the influence of the initial water depth in the pan on the evaporation rate. The results demonstrate that, because of the shelter effect caused by the rim of the pan, the evaporation rates for water depth less than 8 cm are lower than that of standard water depth (20 cm) when wind speed U = 4 and 6 m s-1. However, the shelter effect becomes insignificant when wind speed was U = 2 m s-1.

  3. Changing pan evaporation and its attribution in China

    NASA Astrophysics Data System (ADS)

    Yang, H.; Yang, D.

    2008-12-01

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

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

    SciTech Connect

    Kroener, A. ); Eyal, M.; Eyal, Y. )

    1990-06-01

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

  5. Groundwater evaporation from salt pans: Examples from the eastern Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Schulz, Stephan; Horovitz, Marcel; Rausch, Randolf; Michelsen, Nils; Mallast, Ulf; Köhne, Maximilian; Siebert, Christian; Schüth, Christoph; Al-Saud, Mohammed; Merz, Ralf

    2015-12-01

    The major groundwater resources of the Arabian Peninsula are stored in the large sedimentary basins in its eastern part. Evaporation from continental salt pans (playas) is an important process in water resources assessments of its upper principal aquifers - the Upper Mega Aquifer system - as it constitutes a significant sink. However, literature values on evaporation rates vary widely and usually report about coastal salt pans where seawater evaporation is assumed. The present study applies different methods to provide a comprehensive picture of groundwater evaporation from salt pans of the Upper Mega Aquifer system. A remote sensing approach provided the spatial distribution and total salt pan area of about 36,500 km2. Hydrochemical and isotopic investigations revealed that from about 10% (3600 km2 ± 1600 km2) of the mapped salt pan area seawater evaporates. To estimate the groundwater evaporation rate from continental salt pans a laboratory column experiment was set up, implying a mean annual evaporation rate of about 42 mm ± 13 mm. In-situ analysis of water table fluctuations in the field suggested about 3 mm a-1 originate from recently infiltrated rainwater leading to an annual net groundwater evaporation of 39 mm ± 13 mm. Relating this number to the mapped salt pan area, from which groundwater evaporates, provides a total annual groundwater loss of 1.3 km3 ± 0.5 km3 for the Upper Mega Aquifer system.

  6. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ....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 3-A Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans....

  7. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....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 3-A Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans....

  8. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....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 3-A Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans....

  9. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....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 3-A Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans....

  10. 7 CFR 58.913 - Evaporators and vacuum pans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....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 3-A Sanitary Standards for Milk and Milk Products Evaporators and Vacuum Pans....

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Roderick, Michael

    2013-04-01

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

  13. Application of thermal model for pan evaporation to the hydrology of a defined medium, the sponge

    NASA Technical Reports Server (NTRS)

    Trenchard, M. H.; Artley, J. A. (Principal Investigator)

    1981-01-01

    A technique is presented which estimates pan evaporation from the commonly observed values of daily maximum and minimum air temperatures. These two variables are transformed to saturation vapor pressure equivalents which are used in a simple linear regression model. The model provides reasonably accurate estimates of pan evaporation rates over a large geographic area. The derived evaporation algorithm is combined with precipitation to obtain a simple moisture variable. A hypothetical medium with a capacity of 8 inches of water is initialized at 4 inches. The medium behaves like a sponge: it absorbs all incident precipitation, with runoff or drainage occurring only after it is saturated. Water is lost from this simple system through evaporation just as from a Class A pan, but at a rate proportional to its degree of saturation. The contents of the sponge is a moisture index calculated from only the maximum and minium temperatures and precipitation.

  14. Trends in Thailand pan evaporation from 1970 to 2007

    NASA Astrophysics Data System (ADS)

    Limjirakan, Sangchan; Limsakul, Atsamon

    2012-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

    We show that a simple model of pan evaporation (``PenPan'') can be used to analyze monthly mean output from a global climate model (GCM). PenPan is based on a modified version of Penman's potential evapotranspiration equation. Very good agreement is obtained with observed annual pan evaporation for Australian sites when PenPan is forced by surface observations of radiation, wind speed, humidity and air temperature. When PenPan is forced with monthly mean output from the CSIRO GCM, the results are still satisfactory, but pan evaporation is overestimated over southern Australia, primarily due to excessive surface solar radiation simulated by the GCM. The results suggest that PenPan will be a valuable tool for reconciling observed pan-evaporation trends with climate-model simulations.

  16. Evaporation variability under climate warming in five reanalyses and its association with pan evaporation over China

    NASA Astrophysics Data System (ADS)

    Su, Tao; Feng, Taichen; Feng, Guolin

    2015-08-01

    With the motivation to identify actual evapotranspiration (AE) variability under climate warming over China, an assessment is made from five sets of reanalysis data sets [National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR), NCEP-Department of Energy (NCEP-DOE), Modern-Era Retrospective Analysis for Research and Applications (MERRA), Interim Reanalysis, and Japanese 55-year Reanalysis (JRA-55)]. Based on comparison with AE estimates calculated using the Budyko equation, all five reanalysis data sets reasonably reproduce the spatial patterns of AE over China, with a clearly southeast-northwest gradient. Overall, JRA-55 (NCEP-DOE) gives the lowest (highest) reanalysis evaporation (RE) values. From 1979 to 2013, dominant modes of RE among five reanalyses are extracted using multivariate empirical orthogonal function analysis. Accordingly, the interdecadal variation of RE is likely driven by the change of temperature, and the interannual variation is constrained by the water supply conditions. Under climate warming, RE increase in the Northwest China, Yangtze-Huaihe river basin, and South China, while they decrease in Qinghai-Tibet Plateau, and northern and Northeast China. Moreover, the relationship between RE and pan evaporation (PE) are comprehensively evaluated in space-time. Negative correlations are generally confirmed in nonhumid environments, while positive correlations exist in the humid regions. Our analysis supports the interpretation that the relationship between PE and AE was complementary with water control and proportional with energy control. In view of data availability, important differences in spatial variability and the amount of RE can be found in Northwest China, the Qinghai-Tibet Plateau, and the Yangtze River Basin. Generally speaking, NCEP-NCAR and MERRA have substantial problems on describing the long-term change of RE; however, there are some inaccuracies in the JRA-55 estimates when focusing on the year-to-year variation.

  17. Temporal and spatial characteristics of pan evaporation trends and their attribution to meteorological drivers in the Three-River Source Region, China

    NASA Astrophysics Data System (ADS)

    Wang, Jianhua; Wang, Qingming; Zhao, Yong; Li, Haihong; Zhai, Jiaqi; Shang, Yizi

    2015-07-01

    Pan evaporation is an important indicator of atmospheric evaporative demand, and its long-term variation is of much concern in studies of climate change. Based on data from 33 meteorological stations from 1962 to 2012, this work considered the temporal and spatial trends of pan evaporation and the meteorological variables that affect them in the Three-River Source Region (TRSR) of southwestern China. Pan evaporation in the TRSR has decreased significantly since 1988 with an obvious abrupt change from 1993 to 2003. Furthermore, a 27 year period of oscillation has existed over the past 51 years. Pan evaporation reflects the combined effects of four meteorological variables: net radiation (Rn), wind speed (u2), actual vapor pressure (ea), and air temperature (Ta). Based on this research, a number of conclusions were drawn. (1) The pace of climate change increased after 1980 and pan evaporation decreased at a rate of -13.3 mm/a2 from 1980 to 2012, which is much faster than the rate of -1.2 mm/a2 from 1962 to 1979. (2) For the decrease of pan evaporation from 1980 to 2012, the quantifying contributions of Rn, u2, ea, and Ta were -8.7, -6.4, -1.8, and +3.6 mm/a2, respectively. Thus, it was established for the TRSR that "global dimming" was the main reason, and "wind stilling" was a close second to global dimming for the decrease in pan evaporation. (3) Different regions of the TRSR are affected differently by the effects of the meteorological variables. Low-elevation regions in the TRSR are more susceptible to the effects of net radiation and wind speed, whereas high-elevation regions are affected more by actual vapor pressure and air temperature.

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

    ERIC Educational Resources Information Center

    Canpolat, Nurtac

    2006-01-01

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

  19. Long-Term Trends of Pan Evaporation and an Analysis of Its Causes in Finland

    NASA Astrophysics Data System (ADS)

    Moroizumi, T.; Ito, N.; Koskiaho, J.; Tattari, S.

    2014-12-01

    The recent global warming affects the evapotranspiration which is an important factor of hydrologic cycle and water resources management. Many of the previous studies have reported the decreasing trends of pan evaporation in the area of the continental climate of the middle latitude. However, few studies in the region in a high latitude area such as Finland haven't been carried out so far. The purpose of this study is to investigate the long term variations of pan evaporation in Finland located in high latitude using a trend analysis. The causes of the trends of pan evaporation were discussed from two points of view: a complementary relationship and Penman's equation (1948). The results were summarized as follows: (1) The variations of pan evaporation showed decreasing trends at 5 stations and increasing ones at 2 stations. (2) The mechanistic causes for the decreasing trends at 5 stations were mainly the increases of precipitation and the aerodynamic term in Penman's equation. (3) The mechanistic causes for the increasing trends at 2 stations couldn't be revealed. H. L. Penman. 1948. Natural evaporation from open water, bare soil and grass, Proceedings of the Royal Society of London, Series A, Mathematical and Physical Science, 193, 1032, 129-145.

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

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

  1. 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...

  2. PREDICTING EVAPORATION RATES AND TIMES FOR SPILLS OF CHEMICAL MIXTURES

    EPA Science Inventory


    Spreadsheet and short-cut methods have been developed for predicting evaporation rates and evaporation times for spills (and constrained baths) of chemical mixtures. Steady-state and time-varying predictions of evaporation rates can be made for six-component mixtures, includ...

  3. Evaporation Rates of Brine on Mars

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    PubMed

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

    2013-11-01

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

  5. Evaporation rate and vapor pressure of selected polymeric lubricating oils.

    NASA Technical Reports Server (NTRS)

    Gardos, M. N.

    1973-01-01

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

  6. 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.

  7. Instructions for measuring the rate of evaporation from water surfaces

    USGS Publications Warehouse

    U.S. Geological Survey

    1898-01-01

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

  8. Factors influencing mercury evaporation rate from dental amalgam fillings.

    PubMed

    Bjrkman, L; Lind, B

    1992-12-01

    Factors influencing mercury evaporation from dental amalgam fillings were studied in 11 volunteers. Air was drawn from the oral cavity for 1 min and continuously analyzed with a mercury detector. In six volunteers the median unstimulated evaporation rate was 0.1 ng Hg/s, range 0.09-1.3 ng Hg/s. After chewing gum for 5 min the highest evaporation rate was 2.7 ng Hg/s. Chewing paraffin wax gave only a small increase in evaporation rate. Changes in airflow rates between 1.5 and 2.5 1/min during the 1 min sampling did not change the amount of mercury drawn from the oral cavity. Sampling with different mouthpieces and closed mouth was compared to open mouth sampling with a thin plastic tube. It was found that the latter method could result in lower values for some volunteers due to simultaneous mouth breathing. After placing individual plastic teeth covers in the mouth, the intraoral evaporation of mercury decreased immediately by 89-100% of previous levels. This technique could be used to detect mercury evaporation from separate amalgam fillings or to reduce the intraoral mercury vapor concentration. Rinsing the mouth with heated water for 1 min increased the mean evaporation rate by a factor of 1.7 when the water temperature increased from 35 degrees C to 45 degrees C. PMID:1465570

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

    NASA Astrophysics Data System (ADS)

    Yang, Yan-min; Yang, Yonghui; Han, Shu-min; Hu, Yu-kun

    2009-07-01

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

  10. Ultra-high cooling rate utilizing thin film evaporation

    PubMed Central

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

    2012-01-01

    This research introduces a cell cryopreservation method, which utilizes thin film evaporation and provides an ultra-high cooling rate. The microstructured surface forming the thin film evaporation was fabricated from copper microparticles with an average diameter of 50??m. Experimental results showed that a cooling rate of approximately 5104?C/min was achieved in a temperature range from 10?C to ?187?C. The current investigation will give birth to a cell cryopreservation method through vitrification with relatively low concentrations of cryoprotectants. PMID:23093807

  11. 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.

  12. 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

  13. Studying biofuel aerosol evaporation rates with single particle manipulation

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  14. 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.

  15. Evaporation rates of pasture-mesquite vegetation in central Mexico

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  16. Effect of Concentration on Evaporation Rate for Lithium Bromide Aqueous Solution in a Falling Film Heater

    NASA Astrophysics Data System (ADS)

    Matsuda, Akira; Ide, Tetsuo

    Experiments on evaporation for lithium bromide aqueous solution (0-55 wt% LiBr) were made in Summary a externally heated wetted-wall column under reduced pressures. The evaporation rates of 5 and 8 wt% LiBr-water solutions were similar to those of water. The evaporation rates, however, owered with further increase of the concentration of LiBr, and at low feed rates the evaporation rates lowered with decrease of the feed rate because the temperature of the falling film rose. On the other hand, at high feed rates the evaporation rates lowered with increase of feed rates because the heat transfer coefficients of the falling film decreased. Therefore, a maximum evaporation rate existed and it was supposed that there is the optimum feed rate. The experimental data agreed with the values that were calculated numerically based on the unidirectional model that lithium bromide didn't move through falling film.

  17. An investigation on the effect of evaporation rate on protein crystallization

    NASA Astrophysics Data System (ADS)

    Zhang, Chen-Yan; Dong, Chen; Liu, Yue; Jiang, Bin-Bin; Wang, Meng-Ying; Cao, Hui-Ling; Guo, Wei-Hong; Yin, Da-Chuan

    2015-05-01

    One well-known prerequisite for successful crystallization from solution is a supersaturated solution. To achieve supersaturation, many methods are known, among which solvent evaporation is a common approach. For protein crystallization, the most widely used method is vapor diffusion, in which solvent evaporation from the crystallization solution is the major reason for achieving supersaturation. The solvent evaporation rate may affect the actual concentration distribution in the crystallization solution, thereby influencing the crystallization process. To explore the effect of evaporation rate on protein crystallization, we used lysozyme as a model protein and studied the crystallization success rate at different evaporation conditions. Successful crystallization occurred only when both supersaturation and evaporation rates were in suitable ranges. This study demonstrates that both supersaturation level and the rate of reaching supersaturation (or solvent evaporation rate) are important for lysozyme crystallization. To increase the chance of obtaining crystals, manipulation of solvent evaporation rate is one choice. According to this assumption, we performed crystallization screening trials at different evaporation rates using three model proteins. The trials demonstrate that control of the evaporation rate during crystallization may provide more opportunities to obtain crystals.

  18. Strengthened PAN-based carbon fibers obtained by slow heating rate carbonization

    PubMed Central

    Kim, Min-A; Jang, Dawon; Tejima, Syogo; Cruz-Silva, Rodolfo; Joh, Han-Ik; Kim, Hwan Chul; Lee, Sungho; Endo, Morinobu

    2016-01-01

    Large efforts have been made over the last 40 years to increase the mechanical strength of polyacrylonitrile (PAN)-based carbon fibers (CFs) using a variety of chemical or physical protocols. In this paper, we report a new method to increase CFs mechanical strength using a slow heating rate during the carbonization process. This new approach increases both the carbon sp3 bonding and the number of nitrogen atoms with quaternary bonding in the hexagonal carbon network. Theoretical calculations support a crosslinking model promoted by the interstitial carbon atoms located in the graphitic interlayer spaces. The improvement in mechanical performance by a controlled crosslinking between the carbon hexagonal layers of the PAN based CFs is a new concept that can contribute further in the tailoring of CFs performance based on the understanding of their microstructure down to the atomic scale. PMID:27004752

  19. Strengthened PAN-based carbon fibers obtained by slow heating rate carbonization.

    PubMed

    Kim, Min-A; Jang, Dawon; Tejima, Syogo; Cruz-Silva, Rodolfo; Joh, Han-Ik; Kim, Hwan Chul; Lee, Sungho; Endo, Morinobu

    2016-01-01

    Large efforts have been made over the last 40 years to increase the mechanical strength of polyacrylonitrile (PAN)-based carbon fibers (CFs) using a variety of chemical or physical protocols. In this paper, we report a new method to increase CFs mechanical strength using a slow heating rate during the carbonization process. This new approach increases both the carbon sp(3) bonding and the number of nitrogen atoms with quaternary bonding in the hexagonal carbon network. Theoretical calculations support a crosslinking model promoted by the interstitial carbon atoms located in the graphitic interlayer spaces. The improvement in mechanical performance by a controlled crosslinking between the carbon hexagonal layers of the PAN based CFs is a new concept that can contribute further in the tailoring of CFs performance based on the understanding of their microstructure down to the atomic scale. PMID:27004752

  20. On the effect of marangoni flow on evaporation rates of heated water drops.

    PubMed

    Girard, F; Antoni, M; Sefiane, K

    2008-09-01

    In this letter we show that the Marangoni flow contribution to the evaporation rate of small heated water droplets resting on hot substrates is negligible. We compare data of evaporating droplet experiments with numerical results and assess the effect of Marangoni flow and its contribution to the evaporation process. We demonstrate that heat conduction inside these water droplets is sufficient to give an accurate estimate of evaporation rates. Although convection in evaporating water droplets remains an open problem, our aim in this study is to demonstrate that these effects can be neglected in the investigation of evaporation rate evaluation. It is worth noting that the presented results apply to volatile heated drops which might differ from spontaneously evaporating cases. PMID:18671417

  1. Effect of the rate of temperature increase on water quality during heating in electromagnetic- and gas-heated pans.

    PubMed

    Hiratsuka, Hiroshi; Sasaki, Ken

    2004-04-01

    More rapid increases in the pH value and hardness during electromagnetic heating of a pan of water were observed than when the pan was heated by LNG or LPG. The water quality changed universally in several tap water samples across Japan. This quality change was closely correlated with the rate of temperature increase, irrespective of heating by electromagnetic induction, LNG or LPG. PMID:15118325

  2. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    NASA Astrophysics Data System (ADS)

    Ponomarev, Konstantin; Orlova, Evgeniya; Feoktistov, Dmitry

    2016-02-01

    This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass). A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  3. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

    PubMed Central

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-01-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

  4. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

    NASA Astrophysics Data System (ADS)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-03-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

  5. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

    PubMed

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-01-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

  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 δ2 H = 4.20 δ 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: δ2H = 5.02 δ18O - 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. Effects on evaporation rates from different water-permeable pavement designs.

    PubMed

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

    2011-01-01

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

  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. 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.; Morn-Tejeda, Enrique; Revuelto, Jess; El Kenawy, Ahmed; Martn-Hernndez, Natalia; Tomas-Burguera, Miquel

    2015-04-01

    We analyzed the spatio-temporal evolution of evaporation observations from Pich 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 Pich 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 Pich 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 Pich measurements. Annual and seasonal trends of evaporation estimates show a statistically significant increase for 1961-2011, which do not agree with long-term Pich 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 Pich evaporation observations for other regions are needed to better understand physical components influencing long-term trends of evaporation.

  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. Modeling the evaporation rate of cesium off tungsten based controlled porosity dispenser photocathodes

    NASA Astrophysics Data System (ADS)

    Pan, Z.; Jensen, K. L.

    2013-04-01

    The evaporation of cesium from a tungsten surface is modeled using an effective one-dimensional potential well representation of the binding energy. The model accounts for both local and global interactions of cesium with the surface metal as well as with other cesium atoms. The theory is compared with the data of Taylor and Langmuir [Phys. Rev. 44, 423 (1933), 10.1103/PhysRev.44.423] comparing evaporation rates to sub-monolayer surface coverage of cesium, gives good agreement, and reproduces the nonlinear behavior of evaporation with varying coverage and temperature.

  12. Reservoir evaporation in central Colorado

    USGS Publications Warehouse

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

    1983-01-01

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

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

    PubMed Central

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

    2013-01-01

    Although the requirements for heat dissipation during exercise are determined by the necessity for heat balance, few studies have considered them when examining sweat production and its potential modulators. Rather, the majority of studies have used an experimental protocol based on a fixed percentage of maximum oxygen uptake (%). Using multiple regression analysis, we examined the independent contribution of the evaporative requirement for heat balance (Ereq) and % to whole-body sweat rate (WBSR) during exercise. We hypothesised that WBSR would be determined by Ereq and not by %. A total of 23 males performed two separate experiments during which they exercised for 90 min at different rates of metabolic heat production (200, 350, 500 W) at a fixed air temperature (30C, n= 8), or at a fixed rate of metabolic heat production (290 W) at different air temperatures (30, 35, 40C, n= 15 and 45C, n= 7). Whole-body evaporative heat loss was measured by direct calorimetry and used to calculate absolute WBSR in grams per minute. The conditions employed resulted in a wide range of Ereq (131487 W) and % (1555%). The individual variation in non-steady-state (030 min) and steady-state (3090 min) WBSR correlated significantly with Ereq (P < 0.001). In contrast, % correlated negatively with the residual variation in WBSR not explained by Ereq, and marginally increased (?2%) the amount of total variability in WBSR described by Ereq alone (non-steady state: R2= 0.885; steady state: R2= 0.930). These data provide clear evidence that absolute WBSR during exercise is determined by Ereq, not by %. Future studies should therefore use an experimental protocol which ensures a fixed Ereq when examining absolute WBSR between individuals, irrespective of potential differences in relative exercise intensity. PMID:23459754

  14. A generalized complementary relationship between actual and potential evaporation defined by a reference surface temperature

    NASA Astrophysics Data System (ADS)

    Aminzadeh, Milad; Roderick, Michael L.; Or, Dani

    2016-01-01

    The definition of potential evaporation remains widely debated despite its centrality for hydrologic and climatic models. We employed an analytical pore-scale representation of evaporation from terrestrial surfaces to define potential evaporation using a hypothetical steady state reference temperature that is common to both air and evaporating surface. The feedback between drying land surfaces and overlaying air properties, central in the Bouchet (1963) complementary relationship, is implicitly incorporated in the hypothetical steady state where the sensible heat flux vanishes and the available energy is consumed by evaporation. Evaporation rates predicted based on the steady state reference temperature hypothesis were in good agreement with class A pan evaporation measurements suggesting that evaporation from pans occurs with negligible sensible heat flux. The model facilitates a new generalization of the asymmetric complementary relationship with the asymmetry parameter b analytically predicted for a wide range of meteorological conditions with initial tests yielding good agreement between measured and predicted actual evaporation.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  16. Estimates of evaporation rates from wounds for various dressing/support surface combinations.

    PubMed

    Lachenbruch, Charlie; VanGilder, Catherine

    2012-01-01

    The management of exudate is an essential aspect of wound care. The wound bed must remain moist to promote healing, but care must be taken to remove excess fluid to avoid maceration and subsequent breakdown of the periwound site, which could serve as a possible portal to infection. Excess fluid is typically absorbed into and/or evaporates through the wound dressing or may be managed by a powered vacuum-assisted closure device. Although the moisture vapor permeability has been studied for dressings, the rate of evaporation associated with wound's immediate treatment environment, or dressing/treatment surface interface, has not been addressed to date. It is essential for caregivers to have an understanding of how these 2 interventions work together in order to provide optimal care to the wound patient. The purpose of this study was to provide estimates of evaporative withdrawal rates for various wound dressings and therapeutic support surfaces. PMID:22218068

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

    NASA Astrophysics Data System (ADS)

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

    1992-02-01

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

  18. Morphological Evolution of Gyroid-Forming Block Copolymer Thin Films with Varying Solvent Evaporation Rate.

    PubMed

    Wu, Yi-Hsiu; Lo, Ting-Ya; She, Ming-Shiuan; Ho, Rong-Ming

    2015-08-01

    In this study, we aim to examine the morphological evolution of block copolymer (BCP) nanostructured thin films through solvent evaporation at different rates for solvent swollen polystyrene-block-poly(l-lactide) (PS-PLLA). Interesting phase transitions from disorder to perpendicular cylinder and then gyroid can be found while using a partially selective solvent for PS to swell PS-PLLA thin film followed by solvent evaporation. During the transitions, gyroid-forming BCP thin film with characteristic crystallographic planes of (111)G, (110)G, and (211)G parallel to air surface can be observed, and will gradually transform into coexisting (110)G and (211)G planes, and finally transforms to (211)G plane due to the preferential segregation of constituted block to the surface (i.e., the thermodynamic origin for self-assembly) that affects the relative amount of each component at the air surface. With the decrease on the evaporation rate, the disorder phase will transform to parallel cylinder and then directly to (211)G without transition to perpendicular cylinder phase. Most importantly, the morphological evolution of PS-PLLA thin films is strongly dependent upon the solvent removal rate only in the initial stage of the evaporation process due to the anisotropy of cylinder structure. Once the morphology is transformed back to the isotropic gyroid structure after long evaporation, the morphological evolution will only relate to the variation of the surface composition. Similar phase transitions at the substrate can also be obtained by controlling the ratio of PLLA-OH to PS-OH homopolymers to functionalize the substrate. As a result, the fabrication of well-defined nanostructured thin films with controlled orientation can be achieved by simple swelling and deswelling with controlled evaporation rate. PMID:26151809

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

    EPA Science Inventory

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

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

    USGS Publications Warehouse

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

    1970-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Saykally, Richard J.

    2012-06-01

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

  2. Evaporation Rates for Liquid Water and Ice Under Current Martian Conditions

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Lowell, H. H.

    1953-01-01

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

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

    PubMed

    Boulogne, Franois; 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

  5. Friction, Wear, and Evaporation Rates of Various Materials in Vacuum to 10(exp -7) mm Hg

    NASA Technical Reports Server (NTRS)

    Buckley, Donald H.; Swikert, Max; Johnson, Robert L.

    1961-01-01

    The requirements for bearings and seals to operate in the environment of space dictate a new area for lubrication research. The low ambient pressures encountered in space can be expected to influence the behavior of oil, grease, and solid-film lubricants. The property of these materials most significantly affected by low ambient pressures is the evaporation rate. Various investigators have therefore measured the evaporation rates of oils and greases in vacuum as one method of establishing their relative merit for space applications (1-3). The results of this work have given some indication as to the oils and greases with the greatest stability at reduced ambient pressures. Only limited experimental work, however, has been reported in the literature for inorganic solids and soft metals which have potential use as solid lubricant films or coatings for hard alloy substrates [e.g. Reference ( 4 )]. In general, the evaporation rates of these materials would be lower than those of oils and greases. These films might therefore be very attractive as lubricants for high vacuum service.

  6. Determination of barium and calcium evaporation rates from impregnated tungsten dispenser cathodes

    NASA Astrophysics Data System (ADS)

    Jones, G. L.; Grant, J. T.

    The evaporation rates of barium and calcium from impregnated tungsten dispenser cathodes have been determined by both a vapor-collect method and line-of-sight mass spectrometry. Cathodes having molar ratios of BaO, CaO, and Al 2O 3 of 4:1:1, 5:3:2, and 1:1:1 have been studied. All measurements were conducted in ultrahigh vacuum. For the vapor-collect method, a W(110) collector was found to be suitable for monolayer growth. The procedure involved plotting the ratio of the adsorbate Auger peak-to-peak height to that from the collector as a function of collection time. Break-points in these plots characterized the collection of one monolayer of adsorbate. A geometrical correction then allowed the evaporation rates to be determined. Evaporation rates were determined at cathode temperatures of 1050, 1100, and 1150C. For the line-of-sight mass spectrometry an Extranuclear quadrupole was used. The quadrupole was capable of measuring species up to 300 amu. Measurements with the quadrupole were made on a 5:3:2 and a 4:1:1 cathode. Results obtained using these two methods are compared.

  7. 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

  8. 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 185C for 18 hours. The thicknesses of water repellent layers were 1, 2, 3 and 7 cm on top of wettable soil. Fully wettable soil columns were prepared as a control. Soil columns (8 cm diameter, 10 cm height) were covered with nylon mesh. Tap water (50 ml, saturating 3 cm of a soil column) was injected with hypoderm syringes from three different directions at the bottom level. The injection holes were sealed with hot-melt adhesive immediately after injection. The rate of soil evaporation through the soil surface was measured by weight change under isothermal condition of 40C. Five replications were made for each. A trend of negative correlation between the thickness of water repellent top layer and soil evaporation rate is discussed in this contribution.

  9. Does metabolic rate and evaporative water loss reflect differences in migratory strategy in sexually dimorphic hoverflies?

    PubMed

    Tomlinson, Sean; Menz, Myles H M

    2015-12-01

    A typical explanation for ecologically stable strategies that apply to only a proportion of a population, is bet hedging, where increased reproductive success offsets reduced reproductive rate. One such is partial migration, where only a proportion of a population moves seasonally to avoid inclement climatic conditions. Bet hedging may overlook unseen costs to maintain broad physiological resilience, implied by encountering a breadth of environmental conditions. We investigated the physiological correlates of partial migration by measuring standard metabolic rates, and rates of evaporative water loss, and then estimating upper and lower thermal tolerance in males and females of two hoverfly species, Episyrphus balteatus and Eristalis tenax. In central Europe, females of these species may either migrate or overwinter, whereas males may migrate south to the Mediterranean, but have not been found overwintering. Both species were sexually dimorphic; female Ep. balteatus were lighter than males, but female Er. tenax were heavier than males. While allometrically- corrected metabolic rate in both species increased with temperature, the most parsimonious models included no sex-specific differences in metabolic rate for either species. Evaporative water loss of both species also increased with temperature, but was higher for females of both species than males. Assuming that resting metabolism is congruent with the activity requirements of migration, highly consistent thermal tolerance and metabolic rate suggests that any given fly could migrate, although water loss patterns suggest that females may be less well-adapted to Mediterranean climates. We infer that partial migration probably results from the imperatives of their reproductive strategies. PMID:26384457

  10. In situ measurement and dynamic control of the evaporation rate in vapor diffusion crystallization of proteins

    NASA Astrophysics Data System (ADS)

    Shu, Zhan-Yong; Gong, Hai-Yun; Bi, Ru-Chang

    1998-08-01

    A special device with a weight-sensitive facility was designed for monitoring and controlling the water evaporation in vapor diffusion protein crystallization. The device made it possible to measure the weight of the drop in real time while the crystallization experiment was going on normally. The precise water equilibration curves under different crystallization conditions could be obtained automatically. By monitoring and controlling the evaporation rate, the crystallization of hen egg-white lysozyme and trichosanthin, a plant protein from Chinese herb, was optimized by regulating the reservoir solution dynamically. The experimental results of these two proteins indicate both the feasibility of the device and the usefulness of dynamic control technique. Compared with traditional crystallization experiments, dynamically controlled crystallization can reduce the number of nuclei, increase the crystal size and save experimental time effectively.

  11. Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures

    NASA Technical Reports Server (NTRS)

    Bolgar, A. S.; Verkhoglyadova, T. S.; Samsonov, G. V.

    1985-01-01

    The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  13. Field investigation of evaporation from freshwater tailings

    SciTech Connect

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

    2000-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Li, Wanguang

    Elastic and inelastic light scattering techniques were used to explore the processes of Knudsen evaporation, thermophoresis and gas/droplet reaction related to single microparticles. The reaction between single titanium ethoxide (TTE) droplets with water vapor was investigated. It was found that the fast surface reaction led to the formation of a coated microsphere consisting of a TiO_2 shell and an unreacted core. The thermophoretic force was measured over a wide range of Knudsen number (Kn = lambda/a) for dioctyl phthalate (DOP) droplets and microspheres of polystyrene latex (PSL), glass and nickel in air, helium and carbon dioxide. The data in the transition regime were used to examine existing theories for the thermophoretic force. It was found that the numerical solutions of Loyalka (1992) and the theory of Brock (1962) are in good agreement with measurements in air and carbon dioxide. The results in helium were found to be somewhat higher than most theoretical solutions for monatomic gasses. The effects of the thermal properties of the gases and particles on the thermophoretic force were also investigated. It was found that the force strongly depends on the thermal conductivity of gas and weakly on the thermal conductivity of particle. The effects of surface charge on force were studied in this research for the first time. Negatively -charged particles receive a larger force than those positively -charged. Knudsen evaporation measurements were made for single dioctyl phthalate droplets in air in the temperature regime 263-302 K. The evaporation rates near room temperature (297.7K) were used to evaluate the theories of Loyalka et al. (1989), Fuchs and Sutugin (1970) and Sitarski and Nowakowski (1979). The agreement between the measurements and the solutions of Loyalka et al. (1989) and Fuchs and Sutugin (1970) was good for all values of Kn, but the solution of Sitarski and Nowakowski (1979) did not agree with the experiments at large Kn.

  15. Milagro Limits and HAWC Sensitivity for the Rate-Density of Evaporating Primordial Black Holes

    NASA Technical Reports Server (NTRS)

    Abdo, A. A.; Abeysekara, A. U.; Alfaro, R.; Allen, B.T.; Alvarez, C.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; Ayala Solares, H. A.; Hays, E.

    2014-01-01

    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 approximately 5.0 x 10 (sup 14) grams should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the gigaelectronvolt - teraelectronvolt energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90 percent duty cycle and sensitivity up to 100 teraelectronvolt 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.

  16. Estimation of barium evaporation rate from emission measurement of dispenser cathodes

    NASA Astrophysics Data System (ADS)

    Ravi, M.; Bhat, K. S.

    2003-06-01

    Dispenser cathodes of type M (Os-Ru coated) have been fabricated in the laboratory and tested for their emission characteristics in a sealed glass bulb in a closely spaced diode configuration. It is observed that the pulsed emission current in the temperature limited region decreased with time during the first few hours of operation and later stabilized at a constant value. This initial fall of emission current is attributed to the back bombardment of barium atoms from the anode resulting in an increase in the effective work function of the cathode surface. The decrease in emission current with time was found to follow a t1/2 relation. It was also observed that when the anode was baked at about 800 C B for a few minutes the original emission current was restored, thus suggesting that the barium evaporated on the anode was responsible for such a behavior. A theoretical model has been suggested for estimation of barium evaporation rate from the above time dependent emission phenomenon observed.

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

    SciTech Connect

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

    2015-04-01

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

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

    SciTech Connect

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

    2015-04-01

    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 10? g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV TeV energy range. The Milagro high energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field-of-view, more than 90% duty cycle and sensitivity up to 100 TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. Based on a search on the Milagro data, we report new PBH burst rate density upper limits over a range of PBH observation times. In addition, we report the sensitivity of the Milagro successor, the High Altitude Water Cherenkov (HAWC) observatory, to PBH evaporation events.

  19. 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.; Alvarez, J. D.; Arceo, R.; Arteaga-Velazquez, J. C.; Aune, T.; H. A. Ayala Solares; 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 × 10¹⁴ g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV – TeV energy range. The Milagro high energy observatory, which operated from 2000 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    USGS Publications Warehouse

    Hostetler, S.W.

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  3. Evaporation mitigation using floating modular devices

    NASA Astrophysics Data System (ADS)

    Hassan, M. Mahmudul; Peirson, William Leslie; Neyland, Bryce M.; Fiddis, Nicholas McQuistan

    2015-11-01

    Reducing evaporation losses from open water storages is of paramount importance in the improvement of water security in arid countries, including Australia. Widespread adoption of evaporation mitigation techniques has been prevented by their high capital and maintenance or operating costs. The use of clean, floating recycled materials to mitigate evaporation technique has been investigated systematically at sites within both the coastal and semi-arid zones of Australia. Evaporation reduction systematically increases with the proportion of covered surface. Evaporation is reduced by 43% at coastal site and 37% at arid zone site at the maximum packing densities achievable for a single layer of floating devices. The study highlights the importance of both long-term investigations and the climatic influences in the robust quantification of evaporation mitigation. The effects of solar radiation, temperature, wind speed and relative humidity on the evaporation rate at both study sites have been determined in terms of both the classical Penman model and FAO Penman Monteith model with corresponding pan coefficients quantified. FAO Penman Monteith model better estimates evaporation from the open reference tank.

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

    PubMed

    Ben-Hamo, Miriam; Muoz-Garcia, Agust; Williams, Joseph B; Korine, Carmi; Pinshow, Berry

    2013-02-15

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

  5. Pan-Svalbard growth rate variability and environmental regulation in the Arctic bivalve Serripes groenlandicus

    NASA Astrophysics Data System (ADS)

    Carroll, Michael L.; Ambrose, William G.; Levin, Benjamin S.; Locke V, William L.; Henkes, Gregory A.; Hop, Haakon; Renaud, Paul E.

    2011-11-01

    Growth histories contained in the shells of bivalves provide continuous records of environmental and biological information over lifetimes spanning decades to centuries, thereby linking ecosystem responses to both natural and anthropogenic climatic variations over a range of scales. We examined growth rates and temporal growth patterns of 260 individuals of the circumpolar Greenland Smooth Cockle ( Serripes groenlandicus) collected between 1997 and 2009 from 11 sites around the Svalbard Archipelago. These sites encompass a range of oceanographic and environmental conditions, from strongly Atlantic-influenced conditions on the west coast to high-Arctic conditions in northeast Svalbard. Absolute growth was up to three times greater at the most strongly Atlantic-influenced locations compared to the most Arctic-influenced areas, and growth performance was highest at sites closest to the West Spitsbergen Current. We also developed growth chronologies up to 34 years in length extending back to 1974. Standardized growth indices (SGI) exhibited substantial inter-site variability, but there were also common temporal features including steadily increasing growth from the late 1980's to the mid-1990's followed by a marked shift from relatively greater to poorer growth in the mid-1990's and from 2004 to 2008. This pattern was consistent with phase-shifts in large-scale climatic drivers. Interannual variability in SGI was also related to local manifestations of the large-scale drivers, including sea temperature and sea ice extent. The temporal growth pattern at Rijpfjorden, on northeast Svalbard, was broadly representative (R = 0.81) of the entire dataset. While there were site-related differences in the specific relationships between growth and environmental parameters, the aggregated dataset indicated an overriding regional driver of bivalve growth: the Arctic Climate Regime Index (ACRI). These results demonstrate that sclerochronological proxies can be useful retrospective analytical tools for establishing baselines of ecosystem variability and for identifying key ecosystem drivers across spatial and temporal scales.

  6. Laboratory studies in planetary science and quantitative analysis of evaporation rates under current Martian conditions

    NASA Astrophysics Data System (ADS)

    Moore, Shauntae

    2005-12-01

    Laboratory measurements have been performed that are intended to shed light on several problems in planetary science. Thermoluminescence measurements of ordinary chondrites have been performed as part of an effort to identify the most primitive materials in the solar system. Experiments to study the fractionation of metal and silicate grains on asteroid surfaces have been performed on NASA's microgravity facility because of its relevance to meteorite origins and the exploration of asteroids by robotic spacecraft. The results of these studies are presented in this thesis as a conference presentation whose summary appeared in the journal Meteoritics and Planetary Science and a paper that appeared in the journal Geophysical Research Letters. The rest of the thesis describes measurements on the stability of water on the surface of Mars and is submitted in normal thesis format, although at the time of submission some of this work has appeared in Geophysical Research Letters and some has been submitted to the journal Astrobiology. The thermoluminescence studies were used to derive petrologic classifications for several type 3 ordinary chondrites from North Africa, some of which are very low and have the potential to provide new insights to the early solar system and its formation. The metal-silicate fractionation work suggests that the differences in composition observed among the major chondrite groups, the H, L and LL chondrites, could be the result of processes occurring on the surface of the meteorite parent body, probably an asteroid. They also suggest that minor disturbances of the surface will cause separation of components in the asteroid regolith and this should be borne in mind in robotics exploration of asteroids. The stability of water on Mars was investigated by measuring the evaporation rate of liquid water in a Mars-like environment produced in a large chamber on Earth. The evaporation rates measured are in good agreement with model-dependent theoretical treatments described in the literature in which Fick's Law is adjusted to allow for the greater buoyancy of water relative to carbon dioxide, the major constituent of the martian atmosphere. The results have implications for possible locations of water on Mars.

  7. Effect of temperature-increase rate on drug release characteristics of dextran microspheres prepared by emulsion solvent evaporation process.

    PubMed

    Miyazaki, Yasunori; Onuki, Yoshinori; Yakou, Shigeru; Takayama, Kozo

    2006-11-01

    Microspheres containing theophylline (TH) were prepared from a hydrophobic dextran derivative by an emulsion solvent evaporation process using an acetone/liquid paraffin system. The effects of solvent evaporation rate on particle properties and drug release characteristic of the microspheres were evaluated. The solvent evaporation rate was controlled by the rate of increase in temperature of the water bath, ranging 7.5-30 degrees C/h. Drug release from the microspheres was examined using JPXIV 2nd fluid (pH 6.8) containing 0.1% Tween 80, and was found to be greatly affected by the solvent evaporation rate. The percentage of drug released until 8h varied; from 28% to 84% for 30 and 7.5 degrees C, respectively. Differential scanning calorimetry and powder X-ray diffraction studies revealed that TH partially interacted with the polymer and drug crystallinity was maintained intact in the microspheres. According to scanning electron microscopy observations, all microspheres showed a well-formed spherical particle with a solid interior. The appearances of the microspheres were, however, extremely different. Microspheres prepared at 30 degrees C/h had a very smooth surface, while those prepared at 7.5-15 degrees C/h had a rough surface with large craters. These findings demonstrated that the surface morphology and drug release characteristic were controlled by the rate of increase of temperature. PMID:16828994

  8. 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

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

    PubMed Central

    Salvucci, Guido D.; Gentine, Pierre

    2013-01-01

    The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (Csurf). Csurf accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of Csurf to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that landatmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (aridhumid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and Csurf can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle. PMID:23576717

  10. Out of the frying pan into the air--emersion behaviour and evaporative heat loss in an amphibious mangrove fish (Kryptolebias marmoratus).

    PubMed

    Gibson, Daniel J; Sylvester, Emma V A; Turko, Andy J; Tattersall, Glenn J; Wright, Patricia A

    2015-10-01

    Amphibious fishes often emerse (leave water) when faced with unfavourable water conditions. How amphibious fishes cope with the risks of rising water temperatures may depend, in part, on the plasticity of behavioural mechanisms such as emersion thresholds. We hypothesized that the emersion threshold is reversibly plastic and thus dependent on recent acclimation history rather than on conditions during early development. Kryptolebias marmoratus were reared for 1 year at 25 or 30°C and acclimated as adults (one week) to either 25 or 30°C before exposure to an acute increase in water temperature. The emersion threshold temperature and acute thermal tolerance were significantly increased in adult fish acclimated to 30°C, but rearing temperature had no significant effect. Using a thermal imaging camera, we also showed that emersed fish in a low humidity aerial environment (30°C) lost significantly more heat (3.3°C min(-1)) than those in a high humidity environment (1.6°C min(-1)). In the field, mean relative humidity was 84%. These results provide evidence of behavioural avoidance of high temperatures and the first quantification of evaporative cooling in an amphibious fish. Furthermore, the avoidance response was reversibly plastic, flexibility that may be important for tropical amphibious fishes under increasing pressures from climatic change. PMID:26490418

  11. 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

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

    PubMed

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

    2013-02-01

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

  13. Comparison of diurnal dynamics in evaporation rate between bare soil and moss-crusted soil within a revegetated desert ecosystem of northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Ya-Feng; Wang, Xin-Ping; Pan, Yan-Xia; Hu, Rui

    2016-02-01

    Effects of biological soil crusts (BSCs) on soil evaporation is quite controversial in literature, being either facilitative or inhibitive, and therein few studies have actually conducted direct evaporation measurements. Continuous field measurements of soil water evaporation were conducted on two microlysimeters, i.e., one with sand soil collected from bare sand dune area and the other with moss-crusted soil collected from an area that was revegetated in 1956, from field capacity to dry, at the southeastern edge of the Tengger Desert. We mainly aimed to quantify the diurnal variations of evaporation rate from two soils, and further comparatively discuss the effects of BSCs on soil evaporation after revegetation. Results showed that in clear days with high soil water content (Day 1 and 2), the diurnal variation of soil evaporation rate followed the typical convex upward parabolic curve, reaching its peak around mid-day. Diurnal evaporation rate and the accumulated evaporation amount of moss-crusted soil were lower (an average of 0.90 times) than that of sand soil in this stage. However, as soil water content decreased to a moderately low level (Day 3 and 4), the diurnal evaporation rate from moss-crusted soil was pronouncedly higher (an average of 3.91 times) than that of sand soil, prolonging the duration of this higher evaporation rate stage; it was slightly higher in the final stage (Day 5 and 6) when soil moisture was very low. We conclude that the effects of moss crusts on soil evaporation vary with different evaporation stages, which is closely related to soil water content, and the variation and transition of evaporation rate between bare soil and moss-crusted soil are expected to be predicted by soil water content.

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

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.; Smalley, Richard E.

    2002-01-01

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

  15. Headspace analysis study of evaporation rate of perfume ingredients applied onto skin.

    PubMed

    Vuilleumier, C; Flament, I; Sauvegrain, P

    1995-04-01

    Synopsis Diffusion of perfume ingredients from skin or hair is measured using an original method based on dynamic headspace technology. This has been used for pure odorants, fine fragrances, as well as for perfumed cosmetic applications such as soaps, creams or shampoos, in order to characterize diffusion processes and air/skin or air/hair partitioning. Accordingly, a special collection system, applied on the inner face of the forearm, has been developed, allowing the adsorption of diffusing organic vapours from skin onto Tenax (poly-diphenyl phenylene oxide) with a controlled air flow rate. A simple model composition containing eleven volatile synthetic odorants was prepared in an alcoholic matrix and the solution was applied onto the skin. The diffusion rate of the different components was measured by determining the concentration of each in the gas phase versus time. Conversely, the same experiment was effected by the application of an alcoholic solution of each individual component. In this manner, the relative diffusion from skin of the components alone or mixed was compared using the same experimental technique. The effect of a musky component was also tested. Both compositions (with and without musk) were then applied in a soap base. Thus, following a rigorous protocol, the forearm was washed with the perfumed soap and rinsed with water before collection of the headspace. The results show the different diffusion rates of the individual odorants. In particular, components evaporate slower from the skin when they have been applied from a soap bar compared to when they have been applied from alcoholic solution. We also present results describing the characterization of skin types using a panel comprised of 80 people (40 females and 40 males); amount of sebum, hydration and pH were systematically measured on different parts of the face, the neck as well as the outer and inner faces of the forearm. The panelists were then classified into different sub-groups taking into account these parameters. It should be noted that the foregoing results were obtained on an 'average'skin type. PMID:19250472

  16. 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.

  17. Adjuvant Effects on Evaporation Rates and Wetted Area of Droplets on Waxy Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of an appropriate adjuvant for pesticide applications is a critical process to improve spray deposit characteristics on waxy leaves and to reduce off-target losses. After deposition and evaporation, residue patterns of 500 m sessile droplets that incorporated four classes of adjuvants on fi...

  18. The Effects of Film Thickness and Evaporation Rate on Si-Cu Thin Films for Lithium Ion Batteries.

    PubMed

    Polat, B Deniz; Keles, Ozgul

    2015-12-01

    The reversible cyclability of Si based composite anodes is greatly improved by optimizing the atomic ratio of Si/Cu, the thickness and the evaporation rates of films fabricated by electron beam deposition method. The galvanostatic test results show that 500 nm thick flim, having 10%at. Cu-90%at. Si, deposited with a moderate evaporation rate (10 and 0.9 /s for Si and Cu respectively) delivers 2642.37 mAh g(-1) as the first discharge capacity with 76% Coulombic efficiency. 99% of its initial capacity is retained after 20 cycles. The electron conductive pathway and high mechanical tolerance induced by Cu atoms, the low electrical resistivity of the film due to Cu3Si particles, and the homogeneously distributed nano-sized/amorphous particles in the composite thin film could explain this outstanding electrochemical performance of the anode. PMID:26682413

  19. Weak ac field-induced patterns in vertical deposition of colloids at various evaporation rates

    NASA Astrophysics Data System (ADS)

    Aslam, R.; Pichumani, M.; Gonzlez-Vias, W.

    2015-03-01

    Pattern formation in colloids by weak ac fields in vertical deposition-like configuration at different temperatures has been studied experimentally. At low evaporation (room temperature), the effect of the field leads to the evolution of a one-dimensional array of clusters along the contact line and columnar colloidal dried deposits are obtained at higher evaporation. We investigate the flow dynamics involved in this pattern formation. Homogeneous variation of the contact angle by electrowetting effect becomes unstable and breaks the translational symmetry at the meniscus. Electrokinetic forces together with capillary forces result in the accumulation of particles for pattern formation. The movement of electrically charged colloidal particles is controlled by weak ac electric field even at higher temperatures. We observe the effect of increasing initial particle concentration on the behavior of the clusters for various field frequencies. The average distance between clusters increase monotonically with an increase in the initial particle concentration. We also observe that the average width of columns increases according to the applied field strength.

  20. 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.

  1. Milagro Limits and HAWC Sensitivity for the Rate Density of Evaporating Primordial Black Holes

    NASA Astrophysics Data System (ADS)

    Marinelli, Samuel; HAWC Collaboration; Milagro Collaboration

    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 energetically allowed species of fundamental particles thermally. PBHs with initial masses of order 5 . 0 1010 g should be expiring in the present epoch with bursts of high-energy particles, including gamma radiation in the GeV - TeV energy range. The Milagro high-energy observatory, which operated from 2000 to 2008, is sensitive to the high end of the PBH evaporation gamma-ray spectrum. Due to its large field of view, more than 90% duty cycle, and sensitivity up to 100-TeV gamma rays, the Milagro observatory is well suited to perform a search for PBH bursts. A search of five years of Milagro data yielded no detections at 5 ? and set a local (parsec-scale) upper limit of 3 . 6 104 PBH bursts/year/pc3. In addition, we will report the sensitivity of the Milagro successor, the High-Altitude Water-Cherenkov (HAWC) observatory, to PBH evaporation events. This work was supported by the National Science Foundation.

  2. Effect of pervaporation plate thickness on the rate of methanol evaporation in a passive vapor-feed direct methanol fuel cell

    NASA Astrophysics Data System (ADS)

    Fauzi, N. F. I.; Hasran, U. A.; Kamarudin, S. K.

    2015-09-01

    In a passive vapor-feed direct methanol fuel cell (DMFC), methanol vapor is typically obtained using a pervaporation plate in a process by which liquid methanol contained in the fuel reservoir undergoes a phase change to vapor in the anodic vapor chamber. This work investigates the effect of pervaporation plate thickness on the rate of methanol evaporation using a three-dimensional simulation model developed by varying the plate thickness. A. The rate of methanol evaporation was measured using Darcy's law. The rate of methanol evaporation was found to be inversely proportional to the plate thickness, where the decrease in thickness inevitably lowers the resistance along the plate and consequently increases the methanol transport through the plate. This shows that the plate thickness has a significant influence on the rate of methanol evaporation and thereby plays an important role in improving the performance of the passive vapor-feed direct methanol fuel cell.

  3. On laboratory simulation and the effect of small temperature oscillations about the freezing point and ice formation on the evaporation rate of water on Mars.

    PubMed

    Moore, Shauntae R; Sears, Derek W G

    2006-08-01

    We report measurements of the evaporation rate of water under Mars-like conditions (CO2 atmosphere at 7 mbar and approximately 0 degrees C) in which small temperature oscillations about the freezing point repeatedly formed and removed a thin layer of ice. We found that the average evaporation at 2.7 +/- 0.5 degrees C without an ice layer (corrected for the difference in gravity on Earth and on Mars) was 1.24 +/- 0.12 mm/h, while at -2.1 +/- 0.3 degrees C with an ice layer the average evaporation rate was 0.84 +/- 0.08 mm/h. These values are in good agreement with those calculated for the evaporation of liquid water and ice when it is assumed that evaporation only depends on diffusion and buoyancy. Our findings suggest that such differences in evaporation rates are entirely due to the temperature difference and that the ice layer has little effect on evaporation rate. We infer that the formation of thin layers of ice on pools of water on Mars does not significantly increase the stability of water on the surface of Mars. PMID:16916288

  4. Metabolic rate, evaporative water loss and thermoregulatory state in four species of bats in the Negev desert.

    PubMed

    Muoz-Garcia, Agust; Larran, Paloma; Ben-Hamo, Miriam; Cruz-Neto, Ariovaldo; Williams, Joseph B; Pinshow, Berry; Korine, Carmi

    2016-01-01

    Life in deserts is challenging for bats because of their relatively high energy and water requirements; nevertheless bats thrive in desert environments. We postulated that bats from desert environments have lower metabolic rates (MR) and total evaporative water loss (TEWL) than their mesic counterparts. To test this idea, we measured MR and TEWL of four species of bats, which inhabit the Negev desert in Israel, one species mainly restricted to hyper-arid deserts (Otonycteris hemprichii), two species from semi-desert areas (Eptesicus bottae and Plecotus christii), and one widespread species (Pipistrellus kuhlii). We also measured separately, in the same individuals, the two components of TEWL, respiratory water loss (RWL) and cutaneous evaporative water loss (CEWL), using a mask. In all the species, MR and TEWL were significantly reduced during torpor, the latter being a consequence of reductions in both RWL and CEWL. Then, we evaluated whether MR and TEWL in bats differ according to their geographic distributions, and whether those rates change with Ta and the use of torpor. We did not find significant differences in MR among species, but we found that TEWL was lowest in the species restricted to desert habitats, intermediate in the semi-desert dwelling species, and highest in the widespread species, perhaps a consequence of adaptation to life in deserts. Our results were supported by a subsequent analysis of data collected from the literature on rates of TEWL for 35 bat species from desert and mesic habitats. PMID:26459985

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

    NASA Technical Reports Server (NTRS)

    Zhang, Neng-Li; Chao, David F.

    2001-01-01

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

  6. Enhancement of Li doping/undoping reaction rate of carbonaceous materials by coating with an evaporated metal film

    NASA Astrophysics Data System (ADS)

    Takamura, Tsutomu; Sumiya, Koji; Suzuki, Junji; Yamada, Chikayoshi; Sekine, Kyoichi

    A novel method for enhancing the charge/discharge rate of the graphite anode of Li-ion batteries has been developed. The method involves covering the surface of the carbon material with a film of an appropriate metal. Simple vacuum evaporation was found to be effective in covering the entire surface of a carbon fiber sample. The metals examined were Ag, Au, Bi, In, Pb, Pd, Sn and Zn. All the metals exhibited a more or less rate-enhancing effect, but Ag, Sn and Zn were the most effective. The effect was dependent on the film thickness. The effects of heat-treatment were also studied with an eye toward obtaining a stable cycleability.

  7. 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, Luk; 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.

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

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

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

  9. 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

  10. Evaporation Anisotropy of Forsterite

    NASA Astrophysics Data System (ADS)

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

    1996-03-01

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

  11. 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.

  12. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. 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.

  14. Effects of the rate of evaporation and film thickness on nonuniform drying of film-forming concentrated colloidal suspensions.

    PubMed

    Narita, T; Hbraud, P; Lequeux, F

    2005-05-01

    In this paper, we report on nonuniform distribution of film-forming waterborne colloidal suspensions above the critical concentration phi(c) of the colloidal glass transition during drying. We found that colloidal suspension films dry nonuniformly when the initial rate of evaporation E and/or the initial thickness l(0) are high. We found that a Peclet number Pe, defined as Pe = El(0)/D, where D is the diffusion coefficient of the colloids in the diluted suspensions, does not predict uniformity of drying of the concentrated suspensions, contrary to the reported work on drying of diluted suspensions. Since the colloidal particles are crowded and their diffusive motion is restricted in concentrated suspensions, we assumed that above phi(c) water is transported to the drying surface by hydrodynamic flow along the osmotic pressure gradient. The permeability of water through channels between deforming particles is estimated by adapting the theory of foam drainage. We defined a new Peclet number Pe' by substituting the transport coefficient of flow (defined as the permeability divided by the viscosity, multiplied by the osmotic pressure gradient) for the diffusion coefficient. This extended Peclet number predicted the nonuniform drying with a criterion of Pe' > 1. These results indicate that the mechanism of water transport to the drying surface in concentrated suspensions is water permeation by osmotic pressure, which is faster than mutual diffusion between water and particles --that has been observed in diluted suspensions and discussed by Routh and Russel. The theory fits well the experimental drying curves for various thicknesses and rates of evaporation. The particle distribution in the drying films is also estimated and it is indicated that the latex distribution is nonuniform when Pe' > 1. PMID:15864729

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

    NASA Technical Reports Server (NTRS)

    Christy, John R.

    1989-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Remote measurement of the evaporation of groundwater from arid playas

    NASA Astrophysics Data System (ADS)

    Wadge, G.; Archer, D. J.

    2002-01-01

    We propose that in the restricted circumstances of an arid playa it should be possible to infer the rates of evaporation of groundwater using radar backscatter measurements. To test this we use an empirically derived relationship between backscatter and surface roughness and a model of how surface roughness changes with a continuous process of halite crystal efflorescence. From these we calculate the volume of groundwater that must have evaporated to produce that roughening effect. The method is illustrated with data from the ERS-1 SAR sensor that imaged the Chott el Djerid playa in southern Tunisia during 1992-93. The playa surface is flat and lacks vegetation. The backscatter generally rises over the playa during the summer months and is reduced abruptly by the onset of winter rains as the halite crust formed by evaporation dissolves. The method appears to be valid for the summer months (March-October) on this playa. Independent meteorological station measurements of pan evaporation give evaporation rates lower than the radar-derived rates by factors of 2-3. Shallow-level recycling of sodium and chloride ions during dissolution of the halite crusts by winter rains may account for this disparity.

  18. 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.

  19. 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.

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

    USGS Publications Warehouse

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

    1977-01-01

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

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

    PubMed

    Scott, Carl D; Smalley, Richard E

    2003-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the conformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence. PMID:12908232

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

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.; Smalley, Richard E.

    2003-01-01

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

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

    USGS Publications Warehouse

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

    1994-01-01

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

  4. Determination of an upper limit for the water outgassing rate of the main-belt comet P/2012 T1 (PanSTARRS)

    NASA Astrophysics Data System (ADS)

    O'Rourke, L.; Snodgrass, C.; de Val-Borro, M.; Biver, N.; Bockelée-Morvan, D.; Hsieh, H.; Teyssier, D.; Fernandez, Y.; Küppers, M.; Micheli, M.; Hartogh, P.

    2014-07-01

    A new main-belt comet (MBC) P/2012 T1 (PANSTARRS) was discovered on 2012 October 6, approximately one month after its perihelion, by the Pan-STARRS1 survey based in Hawaii (Wainscoat et al. 2012). It displayed cometary activity upon its discovery with one hypothesis being that the activity was driven by sublimation of ices; as a result, we searched for emission assumed to be driven by the sublimation of subsurface ices. Our search was of the H_{2}O 1_{10}-1_{01} ground-state rotational line at 557 GHz from P/2012 T1 (PANSTARRS) with the Heterodyne Instrument for the Far Infrared (HIFI; de Graauw et al. 2010) onboard the Herschel Space Observatory (Pilbratt et al. 2010) on 2013 January 16, when the object was at a heliocentric distance of 2.504 au and a distance from Herschel of 2.059 au. Perihelion was in early September 2012 at a heliocentric distance of 2.411 au. To analyze the data, we used a molecular excitation model equivalent to that utilized to analyze both Herschel and ground-based cometary observations (Hartogh et al. 2010, 2011; de Val-Borro et al. 2010, 2012ab). While no H_{2}O line emission was detected in our observations, we were able to derive sensitive 3-σ upper limits for the water production rate and column density of < 7.63 × 10^{25} molecules s^{-1} and of < 1.61 × 10^{11} cm^{-2}, respectively. An observation taken on 2013 January 15 using the Very Large Telescope found the MBC to be active during the Herschel observation, suggesting that any ongoing sublimation due to subsurface ice was lower than our upper limit.

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

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

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

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

    PubMed

    Boopathy, R; Sekaran, G

    2013-09-15

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

  7. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  9. 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.

  10. 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)

  11. 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.; Glvez 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.

  12. The pipes of pan.

    PubMed

    Chalif, David J

    2004-12-01

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

  13. Operational estimates of lake evaporation

    NASA Astrophysics Data System (ADS)

    Morton, F. I.

    1983-10-01

    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 a complementary relationship lake evaporation (CRLE) model. The ability of the CRLE model to produce reliable estimates of annual lake evaporation from monthly values of temperature, humidity and sunshine duration (or global radiation) observed in the land environment with no locally optimized coefficients is tested against comparable water-budget estimates for 11 lakes in North America and Africa. Maps of annual lake evaporation and annual net reservoir evaporation (i.e. the difference between lake evaporation and areal evapotranspiration) for the part of Canada to the east of the Pacific Divide and for the southern U.S.A. are presented. An approximate routing technique, which takes into account the effects of depth and salinity on the seasonal pattern of monthly lake evaporation, is formulated and tested against comparable water-budget estimates for 10 lakes in North America and Africa. The results indicate that the CRLE model, with its associated routing technique, is much superior to the other techniques in current use that rely on climatological or pan observations in the land environment.

  14. [Soil evaporation under perforated plastic mulch].

    PubMed

    Li, Yi; Wang, Quanjiu; Wang, Wenyan; Shao, Ming'an

    2005-03-01

    In arid and semiarid regions of northwestern China, where evaporation exceeds precipitation, perforated plastic mulches are widely used to decrease soil water evaporation. To determine the effects of various perforated plastic mulches on soil water evaporation after irrigation, a soil column experiment was conducted, which consisted of six mulches with different perforated rates and four levels of irrigation, and the soil water evaporation from each soil column was measured. The results showed that with 100% perforated mulch, the cumulative evaporation was 2.8-48.5 times higher than that of the control, and increased with increasing irrigation amount. There was a linear relationship between cumulative evaporation and time, which followed the Gardner's theory of bare soil evaporation. A three-factor (evaporation time, perforated rate and irrigation amount) function of cumulative evaporation and the functions of relative cumulative evaporation and cumulative evaporation per unit hole area film were established, which fitted the observed data very well. PMID:15943354

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

    SciTech Connect

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

    2014-03-05

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

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

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

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

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

    SciTech Connect

    Kyser, E

    2007-08-27

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

  18. Effect of sweating set rate on clothing real evaporative resistance determined on a sweating thermal manikin in a so-called isothermal condition (T manikin = T a = T r)

    NASA Astrophysics Data System (ADS)

    Lu, Yehu; Wang, Faming; Peng, Hui; Shi, Wen; Song, Guowen

    2015-07-01

    The ASTM F2370 (2010) is the only standard with regard to measurement of clothing real evaporative resistance by means of a sweating manikin. However, the sweating set-point is not recommended in the standard. In this study, the effect of sweating rate on clothing real evaporative resistance was investigated on a 34-zone "Newton" sweating thermal manikin in a so-called isothermal condition (T manikin = T a = T r). Four different sweating set rates (i.e., all segments had a sweating rate of 400, 800, 1200 ml/hr•m2, respectively, and different sweating rates were assigned to different segments) were applied to determine the clothing real evaporative resistance of five clothing ensembles and the boundary air layer. The results indicated that the sweating rate did not affect the real evaporative resistance of clothing ensembles with the absence of strong moisture absorbent layers. For the clothing ensemble with tight cotton underwear, a sweating rate of lower than 400 ml/hr•m2 is not recommended. This is mainly because the wet fabric "skin" might not be fully saturated and thus led to a lower evaporative heat loss and thereby a higher real evaporative resistance. For vapor permeable clothing, the real evaporative resistance determined in the so-called isothermal condition should be corrected before being used in thermal comfort or heat strain models. However, the reduction of wet thermal insulation due to moisture absorption in different test scenarios had a limited contribution to the effect of sweating rate on the real evaporative resistance.

  19. Skeletal development in Pan paniscus with comparisons to Pan troglodytes.

    PubMed

    Bolter, Debra R; Zihlman, Adrienne L

    2012-04-01

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

  20. The Pan Zhichang Incident

    ERIC Educational Resources Information Center

    Yuchen, Zhu

    2007-01-01

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

  1. Streamer Evaporation

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  2. 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: 4.30.9 eV for N2 and 2.10.4 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.

  3. 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.

  4. Analysis of energy use in tomato evaporation

    SciTech Connect

    Rumsey, T.; Conant, T.

    1980-01-01

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

  5. Pan-Tetris: an interactive visualisation for Pan-genomes

    PubMed Central

    2015-01-01

    Background Large-scale genome projects have paved the way to microbial pan-genome analyses. Pan-genomes describe the union of all genes shared by all members of the species or taxon under investigation. They offer a framework to assess the genomic diversity of a given collection of individual genomes and moreover they help to consolidate gene predictions and annotations. The computation of pan-genomes is often a challenge, and many techniques that use a global alignment-independent approach run the risk of not separating paralogs from orthologs. Also alignment-based approaches which take the gene neighbourhood into account often need additional manual curation of the results. This is quite time consuming and so far there is no visualisation tool available that offers an interactive GUI for the pan-genome to support curating pan-genomic computations or annotations of orthologous genes. Results We introduce Pan-Tetris, a Java based interactive software tool that provides a clearly structured and suitable way for the visual inspection of gene occurrences in a pan-genome table. The main features of Pan-Tetris are a standard coordinate based presentation of multiple genomes complemented by easy to use tools compensating for algorithmic weaknesses in the pan-genome generation workflow. We demonstrate an application of Pan-Tetris to the pan-genome of Staphylococcus aureus. Conclusions Pan-Tetris is currently the only interactive pan-genome visualisation tool. Pan-Tetris is available from http://bit.ly/1vVxYZT PMID:26328606

  6. Computing Evaporation Using Meteorological Data for Hydrological Budget of Lake Wapalanne in NJ School of Conservation

    NASA Astrophysics Data System (ADS)

    Jordan, J. J.; Barrett, K. R.; Galster, J. C.; Ophori, D. U.; Flores, D.; Kelly, S. A.; Lutey, A. M.

    2011-12-01

    Lake Wapalanne is small manmade lake about 5.4 hectares in northwest New Jersey in the Highlands Physiographic province within permanently protected land. The lake's surrounding area consists of forested vegetation and is relatively unoccupied which minimizes human influence. The lake's small size, minimal external influence, geographic isolation, and protected status provide an optimal research environment to record meteorological data used in calculation of potential evaporation. Between July 7h and August 3rd meteorological data was collected from a professional weather station placed on an island directly in the center of Lake Wapalanne. The Vantage Pro2 weather station provided accurate readings of temperate, humidity, wind-speed and direction, precipitation, and atmospheric pressure. A bathometric survey of the lake was conducted to determine the surface area with variations in depth of the lake's water level. Using the collected weather station data, a rate of potential evaporation was determined with several evaporation equations. A quantified volume was then derived from the rate and surface area of the lake. Using small scale evaporation measurements of known volumes of water within small pans placed in the lake water and National Oceanic and Atmospheric Administration evaporation stations near the experiment site, a comparison and validation of the calculated potential evaporation accuracy and regional evaporation is achieved. This three year study is part of an ongoing NSF Research Experience for Undergraduates (REU) project that encompasses additional topics of lake research; see abstract from Kelly et al. AGU 2011 for more information on the lake's hydrologic budget. The results and methods of this study will be of use in future forecasting and baseline measurements of hydrologic budgets for lakes and reservoirs within regional proximity, which provide drinking water to over five million people in the State of New Jersey.

  7. Characterization and Compatibility Studies of Different Rate Retardant Polymer Loaded Microspheres by Solvent Evaporation Technique: In Vitro-In Vivo Study of Vildagliptin as a Model Drug

    PubMed Central

    Dewan, Irin; Islam, Swarnali; Rana, Md. Sohel

    2015-01-01

    The present study has been performed to microencapsulate the antidiabetic drug of Vildagliptin to get sustained release of drug. The attempt of this study was to formulate and evaluate the Vildagliptin loaded microspheres by emulsion solvent evaporation technique using different polymers like Eudragit RL100, Eudragit RS100, Ethyl cellulose, and Methocel K100M. In vitro dissolution studies were carried out in 0.1 N HCl for 8 hours according to USP paddle method. The maximum and minimum drug release were observed as 92.5% and 68.5% from microspheres, respectively, after 8 hours. Release kinetics were studied in different mathematical release models to find out the linear relationship and release rate of drug. The SEM, DSC, and FTIR studies have been done to confirm good spheres and smooth surface as well as interaction along with drug and polymer. In this experiment, it is difficult to explain the exact mechanism of drug release. But the drug might be released by both diffusion and erosion as the correlation coefficient (R2) best fitted with Korsmeyer model and release exponent (n) was 0.45–0.89. At last it can be concluded that all in vitro and in vivo experiments exhibited promising result to treat type II diabetes mellitus with Vildagliptin microspheres. PMID:26640713

  8. Multileg Heat-Pipe Evaporator

    NASA Technical Reports Server (NTRS)

    Alario, J. P.; Haslett, R. A.

    1986-01-01

    Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

  9. Rainfall interception modelling: Is the wet bulb approach adequate to estimate mean evaporation rate from wet/saturated canopies in all forest types?

    NASA Astrophysics Data System (ADS)

    Pereira, F. L.; Valente, F.; David, J. S.; Jackson, N.; Minunno, F.; Gash, J. H.

    2016-03-01

    The Penman-Monteith equation has been widely used to estimate the maximum evaporation rate (E) from wet/saturated forest canopies, regardless of canopy cover fraction. Forests are then represented as a big leaf and interception loss considered essentially as a one-dimensional process. With increasing forest sparseness the assumptions behind this big leaf approach become questionable. In sparse forests it might be better to model E and interception loss at the tree level assuming that the individual tree crowns behave as wet bulbs ("wet bulb approach"). In this study, and for five different forest types and climate conditions, interception loss measurements were compared to modelled values (Gash's interception model) based on estimates of E by the Penman-Monteith and the wet bulb approaches. Results show that the wet bulb approach is a good, and less data demanding, alternative to estimate E when the forest canopy is fully ventilated (very sparse forests with a narrow canopy depth). When the canopy is not fully ventilated, the wet bulb approach requires a reduction of leaf area index to the upper, more ventilated parts of the canopy, needing data on the vertical leaf area distribution, which is seldom-available. In such cases, the Penman-Monteith approach seems preferable. Our data also show that canopy cover does not per se allow us to identify if a forest canopy is fully ventilated or not. New methodologies of sensitivity analyses applied to Gash's model showed that a correct estimate of E is critical for the proper modelling of interception loss.

  10. Forest evaporation models: relationships between stand growth and evaporation

    NASA Astrophysics Data System (ADS)

    Le Maitre, D. C.; Versfeld, D. B.

    1997-06-01

    The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation on the water regime. The basis for this approach is (a) that growth rates are determined by water availability and limited by the maximum water extraction potential, and (b) that stand evaporation is proportional to biomass and biomass increment. The relationships between stand growth and evaporation were modelled for a set of catchment experiments where estimates of both growth and evaporation were available. The predicted mean evaporation, over periods of several years, was generally within 10% of the measured mean annual evaporation (rainfall minus streamflow) when the model from one catchment was applied to other catchments planted with the same species. The residual evaporation, after fitting the models, was correlated with rainfall: above-average rainfall resulted in above-average evaporation. This relationship could be used to derive estimates for dry and wet years. Analyses using the models provide additional evidence that Eucalyptus grandis may be depleting groundwater reserves in catchments where its roots can reach the water table. The models are designed to be integrated into a plantation management system which uses a geographic information system for spatial analysis and modelling. The use of readily available growth parameters as predictor variables may reduce our dependence on intricate process-based models. This is seen as an efficient way of extrapolating existing catchment data reflecting the impacts of forestry on water supplies across a range of sites, climatic zones and species. This approach has the potential for further development, especially in dealing with low flows and faster growing species.

  11. Marangoni Convection and Deviations from Maxwells' Evaporation Model

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    USGS Publications Warehouse

    Harwell, Glenn R.

    2012-01-01

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

  13. The Imager for Mars Pathfinder Insurance Pan

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  14. Evaporation-induced flow around a pendant droplet and its influence on evaporation

    NASA Astrophysics Data System (ADS)

    Somasundaram, S.; Anand, T. N. C.; Bakshi, Shamit

    2015-11-01

    Studies on the evaporation of suspended microlitre droplets under atmospheric conditions have observed faster evaporation rates than the theoretical diffusion-driven rate, especially for rapidly evaporating droplets such as ethanol. Convective flow inside rapidly evaporating droplets has also been reported in the literature. The surrounding gas around the evaporating droplet has, however, been considered to be quiescent in many studies, the validity of which can be questioned. In the present work, we try to answer this question by direct experimental observation of the flow. The possible causes of such a flow are also explored.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  16. 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.

  17. Evaporation from freely falling droplets

    NASA Astrophysics Data System (ADS)

    Spillman, J. J.

    1984-05-01

    Improvements in experimental techniques for studying the behavior of freely falling droplets are reported. The Re has a significant effect on the evaporation rate of a droplet. Above a Re of 24, the flow detaches and a viscous, slow region forms over the rear of the droplet, thus enhancing the evaporation rate. The vortex region elongates above a Re of 30 and extends 0.8 diam to the rear at a Re of 100. Adding a nonvolatile fluid to the water (molasses was used in experiments) results in a lowered evaporation rate. The technique gives a better simulation to actual aircraft spraying conditions, where the toroidal motion of the fluid will produce a small 'skin' of nonvolatile fluid around the droplet.

  18. Evaporation Rate and Development of Wetted Area of Water Droplets with and without Surfactant at Different Locations on Waxy Leaf Surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The evaporation and formation of deposit patterns from single droplets deposited at various locations on waxy leaves were investigated under controlled conditions. Leaf locations included the interveinal area, midrib and secondary vein on both adaxial and abaxial surfaces. Tests were conducted with ...

  19. 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; Jian, Hung-Yu; Foucaud, Sebastien; Norberg, Peder; Bower, R. G.; Cole, Shaun; Arnalte-Mur, Pablo; Draper, P.; Heinis, Sebastien; Phleps, Stefanie; Chen, Wen-Ping; Lee, Chien-Hsiu; Burgett, William; Chambers, K. C.; Denneau, L.; Flewelling, H.; Hodapp, K. W.; 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 massthe 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.

  20. 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

    NASA Astrophysics Data System (ADS)

    Lin, Lihwai; Jian, Hung-Yu; Foucaud, Sebastien; Norberg, Peder; Bower, R. G.; Cole, Shaun; Arnalte-Mur, Pablo; Chen, Chin-Wei; Coupon, Jean; Hsieh, Bau-Ching; Heinis, Sebastien; Phleps, Stefanie; Chen, Wen-Ping; Lee, Chien-Hsiu; Burgett, William; Chambers, K. C.; Denneau, L.; Draper, P.; Flewelling, H.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Metcalfe, N.; Price, Paul A.; Tonry, J. L.; Wainscoat, R. J.; Waters, C.

    2014-02-01

    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 *) relation, as well as the quiescent fraction versus M * 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 > 1014 M ?), 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 massthe 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 1010 M ? in the group/cluster environment.

  1. Changes in the atmospheric evaporative demand in Mexico

    NASA Astrophysics Data System (ADS)

    Agustin Brena-Naranjo, Jose; Pedrozo-Acua, 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.

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

    SciTech Connect

    Sebesta, F.; John, J.; Motl, A.; Watson, J.S.

    1995-12-31

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

  3. Evaporation Induced Isothermal Crystallization of Silicate Melt

    NASA Astrophysics Data System (ADS)

    Nagahara, H.

    1996-03-01

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

  4. 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.; Rest, A.; Price, P. A.; Burgett, W. S.; Chambers, K. C.; Flewelling, H.; Huber, M. E.; Magnier, E. A.; Tonry, J. L.; Metcalfe, N.; Stubbs, C. W.

    2013-12-10

    We present a search for fast optical transients (τ ∼ 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}(τ ∼ 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.

  5. 242-A evaporator vacuum condenser system

    SciTech Connect

    Smith, V.A.

    1994-09-28

    This document is written for the 242-A evaporator vacuum condenser system (VCS), describing its purpose and operation within the evaporator. The document establishes the operating parameters specifying pressure, temperature, flow rates, interlock safety features and interfacing sub-systems to support its operation.

  6. 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

  7. 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

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  9. Wastewater evaporator system

    SciTech Connect

    Gregory, M.W.

    1993-08-31

    A wastewater evaporator system is described comprising in combination: a housing apparatus, including an evaporator tank at atmospheric pressure, and a heater, blower. The control system includes a drive mechanism for providing rotational movement of the plurality of honeycombed plates in the evaporator tank. The blower passes heated air over the rotating plurality of honeycombed plates. The control system also includes a first pump, and first and second floats positioned in the evaporator tank. A source of wastewater is connected to the evaporator tank. The circuit system is energized by a source of alternating current electric power connected to the heater, to the blower, and to the control system. The system is controlled by the first and second floats to allow wastewater to be pumped into the evaporator tank for evaporation and to shut down the system. A wastewater evaporator system is comprised of: a housing apparatus, an evaporator tank, a baffle, a sludge container, a heater, blower, a first and second group of plurality of honeycombed plates, a control system which includes a second motor for providing rotational movement of the plurality of honeycombed plates, the control system further including a first pump, and float positioned in the evaporator tank and connected to the first pump, a source of wastewater connected to the evaporator tank adjacent the baffle, and circuit system energized by a source of electric power connected to the heater, to the first motor, and to the control system for intermittently providing additional wastewater to the evaporator tank as wastewater in the evaporator tank is evaporated as the plurality of honeycombed plates rotates in proximity to the blower means.

  10. Hard-pan soils - Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 76 FR 20831 - Pan American Day and Pan American Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-13

    ... Documents#0;#0; ] Proclamation 8651 of April 8, 2011 Pan American Day and Pan American Week, 2011 By the President of the United States of America A Proclamation Throughout Pan American Day and Pan American Week... American States and declared that ``representative democracy is an indispensable condition for...

  12. The Pan-STARRS Surveys

    NASA Astrophysics Data System (ADS)

    Carter Chambers, Kenneth

    2015-08-01

    The 4 year Pan-STARRS1 Science Mission has now completed and the data will be publicly release by the time of the IAU Assembly. The full data set, including catalogs (100TB database), images (2PB), and metadata, will be available from the STScI MAST archive. The Pan-STARRS1 Surveys include: (1) The 3pi Steradian Survey, (2) The Medium Deep survey of 10 PS1 footprints (7 sq deg each) spaced around the sky; (3) A solar system survey of the ecliptic optimized for the discovery of Near Earth Objects, (4) a Stellar Transit Survey in the galactic bulge; and (5) a time domain Survey of M31.The characteristics of the Pan-STARRS Surveys will be presented, including image quality, depth, cadence, and coverage. Science results span most fields of astronomy from Near Earth Objects to cosmology.The 2nd mission, the Pan-STARRS NEO Survey, is currently underway on PS1 and it will be supplemented by PS2 as it becomes fully operational. PS2 is currently undergoing commissioning and is expected to begin full time science observations with an functional capability similar to PS1 by summer of 2015. The status of PS2 and commissioning data from PS2 will be presented along with a full description of the Pan-STARRS NEO Survey. The prospects for future (beyond 2017) wide field surveys in the Northern Hemisphere will also be discussed.The Pan-STARRS1 Surveys have been made possible through contributions of the Institute for Astronomy of 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 Nos. NNX08AR22G, NNX12AR65G, and NNX14AM74G 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; the Eotvos Lorand University; and the Los Alamos National Laboratory.

  13. African Drum and Steel Pan Ensembles.

    ERIC Educational Resources Information Center

    Sunkett, Mark E.

    2000-01-01

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

  14. Quantifying nonisothermal subsurface soil water evaporation

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  15. 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.

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

    SciTech Connect

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

    1986-09-01

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

  17. On the evaporation of ammonium sulfate solution

    PubMed Central

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

    2009-01-01

    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 vaporliquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly. PMID:19861551

  18. 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.

  19. The Pan-STARRS Surveys

    NASA Astrophysics Data System (ADS)

    Chambers, Kenneth C.; Pan-STARRS Team

    2016-01-01

    The 4 year Pan-STARRS1 Science Mission has now completed and the final data processing and database ingest is underway. We expect to have the public release of the PS1 Survey data at approximately the time of the AAS Meeting. The full data set, including catalogs (150 Terabyte database), images (2 Petabytes), and metadata, will be available from the STScI MASTarchive. The Pan-STARRS1 Surveys include: (1) The 3pi Steradian Survey, (2) The Medium Deep survey of 10 PS1 footprints (7 sq deg each) spaced around the sky; (3) A solar system survey of the ecliptic optimized for the discovery of Near Earth Objects, (4) a Stellar Transit Survey in the galactic bulge; and (5) a time domain Survey of M31. The characteristics of the Pan-STARRS1 Surveys will be presented, including image quality, depth, cadence, and coverage. Science results span most fields of astronomy from Near Earth Objects to cosmology. The 2nd mission, the Pan-STARRS NEO Survey, is currently underway on PS1 and it will be supplemented by PS2 observations as PS2 becomes fully operational. We will also report on the status of PS2 and the prospects for future wide field surveys in the Northern Hemisphere. The Pan-STARRS1 Surveys have been made possible through contributions of the Institute for Astronomy of 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; the Eotvos Lorand University; and the Los Alamos National Laboratory.

  20. 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.

  1. Effects of nanoparticles on nanofluid droplet evaporation

    SciTech Connect

    Chen, Ruey-Hung; Phuoc, Tran X.; Martello, Donald

    2010-09-01

    Laponite, Fe2O3 and Ag nanoparticles were added to deionized water to study their effect of evaporation rates. The results show that these nanofluid droplets evaporate at different rates (as indicated by the evaporation rate constant K in the well known D2-law) from the base fluid. Different particles lead to different values of K. As the particle concentration increases due to evaporation. K values of various Ag and Fe2O3 nanofluids go through a transition from one value to another, further demonstrating the effect of increasing nanoparticle concentration. The implication for the heat of vaporization (hfg) is discussed.

  2. Measure Guideline: Evaporative Condensers

    SciTech Connect

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

    2012-03-01

    This measure guideline on evaporative condensers provides information on properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices.

  3. 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

  4. Evaporation from partially covered water surfaces

    NASA Astrophysics Data System (ADS)

    Assouline, S.; Narkis, K.; Or, D.

    2010-10-01

    Evaporative losses from large water bodies may exceed 20% of water used in irrigated agriculture, with losses from reservoirs estimated at 50% of storage capacity. Prominent among proposed methods to curtail these evaporative losses are various forms of partial covers placed over water surfaces. Studies show that evaporation through perforated covers and from partially covered water surfaces exhibit nonlinear behavior, where rates of water loss are not proportional to uncovered surface fraction and are significantly affected by opening size and relative spacing. We studied evaporation from small water bodies under various perforated covers, extending the so-called diameter law to opening sizes in the range of 10-5 to 10-1 m. Contradicting claims concerning effects of openings and their arrangement on performance of evaporation barriers are analyzed on per opening and on per area mass losses. Our results help reconcile some classical findings invoking detailed pore-scale diffusion and simple temperature-based energetic behaviors. For fixed relative spacing, area-averaged evaporative flux density remains nearly constant across several orders of magnitude variations in opening size. For the scale of the experimental setup, we predict relative evaporation reduction efficiency for various configurations of perforated evaporation barriers.

  5. Dynamics of evaporative colloidal patterning

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  6. Evaporative modeling for idealized lithographic pores

    NASA Astrophysics Data System (ADS)

    Oinuma, Ryoji; Best, Frederick

    2002-01-01

    As a demand for the high performance and small size electronics devices increased, the heat removal from those electronic devices for space use is getting critical factor more than devices on the earth due to the limitation of the size. The purpose of this paper is to show a study of optimized size of coherent pores or slits in the evaporative wick of a heat pipe to cool down the high heat flux density heat source. Our system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting between the heat source and the evaporator. The evaporation rate of working fluid along the meniscus interface in a micro-order pore or slit was calculated based on the kinetic theory and the statistical rate theory to find a proper diameter of pores to cool down the heat source effectively. The results show the smaller diameter of pores is preferred to achieve the smallest total size of the evaporator although it will involve the cost issue. As a demand for the high performance and small size electronics devices increased, the heat removal from those electronic devices for space use is getting critical factor more than devices on the earth due to the limitation of the size. The purpose of this paper is to show a study of optimized size of coherent pores or slits in the evaporative wick of a heat pipe to cool down the high heat flux density heat source. Our system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting between the heat source and the evaporator. The evaporation rate of working fluid along the meniscus interface in a micro-order pore or slit was calculated based on the kinetic theory and the statistical rate theory to find a proper diameter of pores to cool down the heat source effectively. The results show that the smaller diameter of pores uses the pore for evaporation effectively and is preferred to achieve the smallest total size of the evaporator for the same heat removal performance. As the demand for high performance and small size in electronics devices has increased, heat removal from these electronic devices is a critical factor. Lithographic techniques have been used to produce micron scale pore and surface structures in silicon. These are referred to as coherent wick structures. The purpose of this paper is to describe a study of optimized coherent pores or slits in the evaporative wick of a heat pipe with the high heat flux density heat source. The system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting the heat source and the evaporator. The evaporation along the meniscus interface in a micron scale pore or slit is calculated based on kinetic theory and statistical rate theory to optimize the diameter of pores. Calculations show that 80% of the evaporative energy is carried away in only less than 50% of the pore outer radius. Further, the results show that the smaller pore size has the higher evaporation rate per horizontal area and is preferred to achieve the smallest total size of the evaporator for the same heat removal performance. .

  7. 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 ...

  8. Flash evaporator systems test

    NASA Technical Reports Server (NTRS)

    Dietz, J. B.

    1976-01-01

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

  9. The simultaneous mass and energy evaporation (SM2E) model.

    PubMed

    Choudhary, Rehan; Klauda, Jeffery B

    2016-04-01

    In this article, the Simultaneous Mass and Energy Evaporation (SM2E) model is presented. The SM2E model is based on theoretical models for mass and energy transfer. The theoretical models systematically under or over predicted at various flow conditions: laminar, transition, and turbulent. These models were harmonized with experimental measurements to eliminate systematic under or over predictions; a total of 113 measured evaporation rates were used. The SM2E model can be used to estimate evaporation rates for pure liquids as well as liquid mixtures at laminar, transition, and turbulent flow conditions. However, due to limited availability of evaporation data, the model has so far only been tested against data for pure liquids and binary mixtures. The model can take evaporative cooling into account and when the temperature of the evaporating liquid or liquid mixture is known (e.g., isothermal evaporation), the SM2E model reduces to a mass transfer-only model. PMID:26595699

  10. The Pan-STARRS search for Near Earth Objects

    NASA Astrophysics Data System (ADS)

    Wainscoat, Richard; Weryk, Robert; Schunova, Eva; Carter Chambers, Kenneth

    2015-08-01

    The two Pan-STARRS telescopes, located on Haleakala, Maui, Hawaii, are 1.8-meter diameter telescopes equipped with 1.4 Gigapixel cameras that deliver 7 square degree fields of view. The first of these telescopes, Pan-STARRS1 (PS1), is now conducting a dedicated survey for Near-Earth Objects. The second telescope, Pan-STARRS2 (PS2) is being commissioned.The PS1+PS2 surveys now extend south to -47.5 degrees declination. The image quality in the deep southern sky from Haleakala is good, and the new southern extension to the survey area has been very productive.PS1 discovered more than half of the larger NEOs and PHAs in 2014, and has become the leading NEO discovery telescope. PS1 delivers excellent astrometry and photometry. PS1 continues to discover a significant number of large (> 1km) NEOs.The Pan-STARRS telescopes are very efficient at detecting cometary activity. PS1 discovered almost half of the new comets in 2014, and discovered 10 comets in 10 nights in November 2014.The discovery rate of NEO candidates by PS1 is now overwhelming the external NEO follow-up resources, particularly for fainter NEOs. It has required that PS1 repeat fields to recover NEO candidates. As PS2 matures, and when G96 has its new camera, the combination of these three telescopes will facilitate a higher NEO discovery rate, and a better census of the NEOs in the sky. This will in turn lead to a better understanding of the size and orbit distribution of NEOs, and the corresponding hazard to Earth. The Pan-STARRS NEO survey is also likely to discover asteroids suitable for the NASA asteroid redirect mission.

  11. CAPSULE REPORT: EVAPORATION PROCESS

    EPA Science Inventory

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

  12. Measure Guideline: Evaporative Condensers

    SciTech Connect

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

    2012-03-01

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

  13. 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.

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

    SciTech Connect

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

    1995-11-01

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

  15. Trends and Patterns of Change in Temperature and Evaporation

    NASA Astrophysics Data System (ADS)

    Ragno, E.; AghaKouchak, A.

    2014-12-01

    Global mean monthly temperature has increased substantially in the past decades. On the other hand, there are contradictory reports on the response of the potential evaporation to a warming climate. In this study, ground based observations of temperature, and direct measurements of pan potential evaporation are evaluated across the United States. Furthermore, empirical simulations of the potential evaporation have been evaluated against observations. The results show that empirical (e.g., Thornthwaite method) estimates of the potential evapotranspiration show trends inconsistent with the ground-based observations. In fact, while temperature data show a significant upward trend across most of the United States, ground-based evaporation data in most locations do not exhibit a statistically significant trend. Empirical methods of potential evaporation estimation, including the Thornthwaite method, show trends similar to temperature. The primary reason is that many of the empirical approaches are dominated by temperature. Currently, empirical estimates of potential evaporation are widely used for numerous applications including water stress analysis. This indicates that using empirical estimates of potential estimation for irrigation water demand estimation and also drought assessment could lead to unrealistic results.

  16. WTP Pilot-Scale Evaporation Tests

    SciTech Connect

    QURESHI, ZAFAR

    2004-03-01

    This report documents the design, assembly, and operation of a Pilot-Scale Evaporator built and operated by SRTC in support of Waste Treatment Plant (WTP) Project at the DOE's Hanford Site. The WTP employs three identical evaporators, two for the Waste Feed and one for the Treated LAW. The Pilot-Scale Evaporator was designed to test simulants for both of these waste streams. The Pilot-Scale Evaporator is 1/76th scale in terms of evaporation rates. The basic configuration of forced circulation vacuum evaporator was employed. A detailed scaling analysis was performed to preserve key operating parameters such as basic loop configuration, system vacuum, boiling temperature, recirculation rates, vertical distances between important hardware pieces, reboiler heat transfer characteristics, vapor flux, configuration of demisters and water spray rings. Three evaporation test campaigns were completed. The first evaporation run used water in order to shake down the system. The water runs were important in identifying a design flaw that inhibited mixing in the evaporator vessel, thus resulting in unstable boiling operation. As a result the loop configuration was modified and the remaining runs were completed successfully. Two simulant runs followed the water runs. Test 1: Simulated Ultrafiltration Recycles with HLW SBS, and Test 2: Treated AN102 with Envelop C LAW. Several liquid and offgas samples were drawn from the evaporator facility for regulatory and non-regulatory analyses. During Test 2, the feed and the concentrate were spiked with organics to determine organic partitioning. The decontamination factor (DF) for Test 1 was measured to be 110,000 (more than the expected value of 100,000). Dow Corning Q2-3183A antifoam agent was tested during both Tests 1 and 2. It was determined that 500 ppm of this antifoam agent was sufficient to control the foaminess to less than 5 per cent of the liquid height. The long-term testing (around 100 hours of operation) did not show any fouling of reboiler or other loop piping. The Pilot-Scale Evaporator will be used in the Semi-Integrated Pilot Plant tests. Additionally, the Pilot-Scale design can easily accommodate hardware changes that result from the development of the full-scale evaporator to resolve any issues arising from the startup or operation of the full-scale facility.

  17. Experimental results on evaporation waves

    NASA Astrophysics Data System (ADS)

    Grana Otero, Jose; Parra Fabian, Ignacio

    2010-11-01

    A liquid contained in a vertical glass tube is suddenly depressurized from a high initial pressure down to one for which the stable state is vapour, so vaporization sets off at the free surface. For large enough evaporation rates, the planar vapour-liquid interface is Darrieus-Landau unstable [1], leading to the interface surface rippling close to the instability threshold. Further increasing the initial to final pressure ratio brings about evaporation waves [2,3], in which a highly corrugated front propagates downwards into the liquid. A new experimental method is presented as well as some experimental results obtained by tracking the evolution of the front with a high speed camera. In addition, a number of new phenomena related to the dynamics of bubbles growth at the walls has been uncovered. In particular, a new mode of propagation of the evaporation front is found. In this mode the front originates from below the interface, so the propagation is upwards against gravity with a curved but smooth front.[4pt] [1] F. J. Higuera, Phys. Fluids, V. 30, 679 (1987).[0pt] [2] J.E.Shepherd and B.Sturtevant, J.Fluid Mech., V.121,379 (1982).[0pt] [3] P.Reinke and G.Yadigaroglu, Int.J.Multiph. Flow, V.27,1487 (2001).

  18. A Hundred Years of Peter Pan

    ERIC Educational Resources Information Center

    Hollindale, Peter

    2005-01-01

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

  19. Peroxyacetyl nitrate (PAN) in the urban atmosphere.

    PubMed

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

    2013-11-01

    Peroxyacetyl nitrate (PAN) in air has been well known as the indicator of photochemical smog due to its frequent occurrences in Seoul metropolitan area. This study was implemented to assess the distribution characteristics of atmospheric PAN in association with relevant parameters measured concurrently. During a full year period in 2011, PAN was continuously measured at hourly intervals at two monitoring sites, Gwang Jin (GJ) and Gang Seo (GS) in the megacity of Seoul, South Korea. The annual mean concentrations of PAN during the study period were 0.64±0.49 and 0.57±0.46 ppb, respectively. The seasonal trends of PAN generally exhibited dual peaks in both early spring and fall, regardless of sites. Their diurnal trends were fairly comparable to each other. There was a slight time lag (e.g., 1 h) in the peak occurrence pattern between O3 and PAN, as the latter trended to peak after the maximum UV irradiance period (16:00 (GJ) and 17:00 (GS)). The concentrations of PAN generally exhibited strong correlations with particulates. The results of this study suggest that PAN concentrations were affected sensitively by atmospheric stability, the wet deposition of NO2, wind direction, and other factors. PMID:23838043

  20. 49 CFR 230.69 - Ash pans.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Ash pans. 230.69 Section 230.69 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans ...

  1. 49 CFR 230.69 - Ash pans.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Ash pans. 230.69 Section 230.69 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans ...

  2. 49 CFR 230.69 - Ash pans.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Ash pans. 230.69 Section 230.69 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans ...

  3. 49 CFR 230.69 - Ash pans.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Ash pans. 230.69 Section 230.69 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans ...

  4. 49 CFR 230.69 - Ash pans.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Ash pans. 230.69 Section 230.69 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Ash Pans ...

  5. African Drum and Steel Pan Ensembles.

    ERIC Educational Resources Information Center

    Sunkett, Mark E.

    2000-01-01

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

  6. 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

  7. 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.

  8. Dry deposition of pan to grassland vegetation

    SciTech Connect

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

    1994-01-01

    Peroxyacetyl nitrate or PAN (CH{sub 3}C(O)OONO{sub 2}) is formed in the lower troposphere via photochemical reactions involving nitrogen oxides (NO{sub x}) and non-methane hydrocarbons (NMHCs). PAN has a lifetime in the free troposphere of about three months and is removed by photolysis or reaction with OH. Dry deposition will decrease its lifetime, although the few measurements that have been made indicate that this process is slow. Measurements of the uptake of PAN by alfalfa in growth chambers indicated that the dry deposition velocity (downward flux divided by concentration at a specified height) was 0.75 cm s{sup {minus}1}. Garland and Penkett measured a dry deposition velocity of 0.25 cm s{sup {minus}1} for PAN to grass and soil in a return-flow wind tunnel. Shepson et al. (1992) analyzed trends of PAN and O{sub 3} concentrations in the stable nocturnal boundary layer over mixed deciduous/coniferous forests at night, when leaf stomata were closed, and concluded that the deposition velocity for PAN was at least 0.5 cm s{sup {minus}1}. We measured the dry deposition velocity of PAN to a grassland site in the midwestern United States with a modified Bowen ratio technique. Experiments were conducted on selected days during September, October, and November of 1990. An energy balance Bowen ratio station was used to observe the differences in air temperature and water vapor content between heights of 3.0 and 0.92 m and to evaluate the surface energy balance. Air samples collected at the same two heights in Teflon {reg_sign} bags were analyzed for PAN by a gas chromatographic technique. We present an example of the variations of PAN concentrations and gradients observed during the day and compare measurements of the dry deposition velocity to expectations based on the physicochemical properties of PAN.

  9. Mobile evaporator corrosion test results

    SciTech Connect

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    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, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

  10. An evaporation based digital microflow meter

    NASA Astrophysics Data System (ADS)

    Nie, C.; Frijns, A. J. H.; Mandamparambil, R.; Zevenbergen, M. A. G.; den Toonder, J. M. J.

    2015-11-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes place. A proof-of-principle device of the digital flow meter was designed, fabricated, and tested. The device was built on foil-based technology. In the proof-of-principle experiments, good agreement was found between set flow rates and the evaporation rates estimated from reading the number of wetted pore structures. The measurement range of the digital flow meter can be tuned and extended in a straightforward manner by changing the pore structure of the device.

  11. Internal dynamics of evaporating droplets

    SciTech Connect

    Esmaeeli, A.; Arpaci, V.; Chai, A.T.

    1996-12-31

    The full Navier-Stokes equations and the energy equation are solved for the fluid inside and outside of a droplet using a front tracking/finite difference method. The boundaries of the domain are taken periodic in the horizontal direction and wall bounded in the vertical direction. The behavior of a two-dimensional deformable liquid drop in zero gravity is studied and the dynamics of the flow is analyzed. The effects of governing nondimensional parameters on the evaporation rate are also discussed.

  12. Laser evaporation studies

    NASA Astrophysics Data System (ADS)

    Sankur, H.

    1986-10-01

    The use of a pulsed laser to evaporate dielectric materials for optical thin film deposition was investigated. The electrical properties of the laser induced plasma in the evaporant plume were studied. High flux (20A/sq cm) of high velocity (1 to 10 million) cm/s) ionic species were observed in the TEA-CO2 laser evaporation of many refractory oxides, chalcogenides and fluorides. Thin films of ZrO2 were deposited out of a plasma described above. These films were dense, oriented polycrystalline and had bulk refractive index values (2,15), low absorption (K about 0.001) and low particulate density for a range of laser fluence values. In the next and final phase of this project, thin film studies will be extended to a wider array of materials, with emphasis on obtaining high quality films with low particulate densities.

  13. 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)..

  14. Hot air drum evaporator

    DOEpatents

    Black, Roger L.

    1981-01-01

    An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

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

    PubMed

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

    2013-12-01

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

  16. Studies on droplet evaporation and combustion in high pressures

    NASA Technical Reports Server (NTRS)

    Sato, J.

    1993-01-01

    High pressure droplet evaporation and combustion have been studied up to 15 MPa under normal and microgravity fields. From the evaporation studies, it has been found that in the supercritical environments, the droplet evaporation rate and lifetime take a maximum and a minimum at an ambient pressure over the critical pressure. Its maximum and minimum points move toward the lower ambient pressures if the ambient temperature is increased. It has been found from the combustion studies that the burning life time takes a minimum at an ambient pressure being equal to the critical pressure. It is attributable to both the pressure dependency of the diffusion rate and the droplet evaporation characteristics described above.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  18. TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

    SciTech Connect

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

    2009-01-27

    The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tank toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.

  19. Evaporation from partially covered water surfaces

    NASA Astrophysics Data System (ADS)

    Assouline, S.; Or, D.

    2009-12-01

    Evaporative losses from large water bodies may exceed 20% of water used in irrigated agriculture, with losses from reservoirs estimated at 50% of storage capacity. Among the proposed methods to curtail these losses are various forms of partial covers placed on water surfaces. Studies show that evaporation through perforated membranes and from partially covered water surfaces exhibit nonlinear behavior, where rates of water losses may be disproportional relative to the fraction of the uncovered surface, and are significantly affected by openings size and relative spacing. We studied evaporation from small water bodies under various perforated covers, extending the so-called diameter law to opening sizes in the range of 10-5 to 10-1 m. Contradicting claims regarding effects of openings and their arrangement on performance of evaporation barriers are analyzed on per-opening and per-area mass losses. Our results may help reconcile some classical findings invoking detailed pore scale diffusion and simple temperature-based energetic behaviors. For fixed relative spacing, flux density remains nearly constant across several orders of magnitude in opening size. We predict relative evaporation reduction efficiency for various configurations of perforated evaporation barriers.

  20. 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 -7MPa. As opposed to receding menisci observed in microchannel evaporation, the menisci in nanochannels are pinned at the entrance while vapor bubbles form and expand inside. Evaporation in the channels is found to be aided by advective liquid transport, which leads to an evaporation rate that is an order of magnitude higher than that governed by Fickian vapor diffusion in macro- and microscale evaporation. The vapor bubbles also exhibit unusual motion as well as translational stability and symmetry, which occur because of a balance between two competing mass fluxes driven by thermocapillarity and evaporation. Our studies expand our understanding of cavitation and provide new insights for phase-change phenomena at the nanoscale. PMID:22343530

  1. Optimized evaporation technique for leachate treatment: Small scale implementation.

    PubMed

    Benyoucef, Fatima; Makan, Abdelhadi; El Ghmari, Abderrahman; Ouatmane, Aziz

    2016-04-01

    This paper introduces an optimized evaporation technique for leachate treatment. For this purpose and in order to study the feasibility and measure the effectiveness of the forced evaporation, three cuboidal steel tubs were designed and implemented. The first control-tub was installed at the ground level to monitor natural evaporation. Similarly, the second and the third tub, models under investigation, were installed respectively at the ground level (equipped-tub 1) and out of the ground level (equipped-tub 2), and provided with special equipment to accelerate the evaporation process. The obtained results showed that the evaporation rate at the equipped-tubs was much accelerated with respect to the control-tub. It was accelerated five times in the winter period, where the evaporation rate was increased from a value of 0.37 mm/day to reach a value of 1.50 mm/day. In the summer period, the evaporation rate was accelerated more than three times and it increased from a value of 3.06 mm/day to reach a value of 10.25 mm/day. Overall, the optimized evaporation technique can be applied effectively either under electric or solar energy supply, and will accelerate the evaporation rate from three to five times whatever the season temperature. PMID:26826455

  2. Waste Feed Evaporation Physical Properties Modeling

    SciTech Connect

    Daniel, W.E.

    2003-08-25

    This document describes the waste feed evaporator modeling work done in the Waste Feed Evaporation and Physical Properties Modeling test specification and in support of the Hanford River Protection Project (RPP) Waste Treatment Plant (WTP) project. A private database (ZEOLITE) was developed and used in this work in order to include the behavior of aluminosilicates such a NAS-gel in the OLI/ESP simulations, in addition to the development of the mathematical models. Mathematical models were developed that describe certain physical properties in the Hanford RPP-WTP waste feed evaporator process (FEP). In particular, models were developed for the feed stream to the first ultra-filtration step characterizing its heat capacity, thermal conductivity, and viscosity, as well as the density of the evaporator contents. The scope of the task was expanded to include the volume reduction factor across the waste feed evaporator (total evaporator feed volume/evaporator bottoms volume). All the physical properties were modeled as functions of the waste feed composition, temperature, and the high level waste recycle volumetric flow rate relative to that of the waste feed. The goal for the mathematical models was to predict the physical property to predicted simulation value. The simulation model approximating the FEP process used to develop the correlations was relatively complex, and not possible to duplicate within the scope of the bench scale evaporation experiments. Therefore, simulants were made of 13 design points (a subset of the points used in the model fits) using the compositions of the ultra-filtration feed streams as predicted by the simulation model. The chemistry and physical properties of the supernate (the modeled stream) as predicted by the simulation were compared with the analytical results of experimental simulant work as a method of validating the simulation software.

  3. 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.

  4. Handedness in captive bonobos (Pan paniscus).

    PubMed

    Harrison, Rebecca M; Nystrom, Pia

    2008-01-01

    Species level right-handedness is often considered to be unique to humans. Handedness is held to be interrelated to our language ability and has been used as a means of tracing the evolution of language. Here we examine handedness in 3 captive groups of bonobos (Pan paniscus) comprising 22 individuals. We found no evidence for species level handedness. Conclusions that can be drawn from these findings are: (1) species level handedness evolved after the divergence of the Pan and Homo lineages; (2) inconsistent preferences may represent precursors to human handedness, and (3) Pan may have language abilities but these cannot be measured using handedness. PMID:18212503

  5. Structuring of polymer solutions upon solvent evaporation.

    PubMed

    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. PMID:25768523

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    Gonzalez, Mark A.; Walter, Wayne W.

    2014-03-01

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

  8. 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.

  9. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  10. 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.

  11. 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

  12. Pan-information Location Map

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  13. MOVES2014: Evaporative Emissions Report

    EPA Science Inventory

    Vehicle evaporative emissions are now modeled in EPAs MOVES according to physical processes, permeation, tank vapor venting, liquid leaks, and refueling emissions. With this update, the following improvements are being incorporated into MOVES evaporative emissions methodology, a...

  14. MOVES2014: Evaporative Emissions Report

    EPA Science Inventory

    Vehicle evaporative emissions are now modeled in EPA’s MOVES according to physical processes, permeation, tank vapor venting, liquid leaks, and refueling emissions. With this update, the following improvements are being incorporated into MOVES evaporative emissions methodology, a...

  15. 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).

  16. Pan-tropical monitoring of deforestation

    NASA Astrophysics Data System (ADS)

    Achard, F.; DeFries, R.; Eva, H.; Hansen, M.; Mayaux, P.; Stibig, H.-J.

    2007-10-01

    This paper reviews the technical capabilities for monitoring deforestation from a pan-tropical perspective in response to the United Nations Framework Convention on Climate Change (UNFCCC) process, which is studying the technical issues surrounding the ability to reduce greenhouse gas emissions from deforestation in developing countries. The successful implementation of such policies requires effective forest monitoring systems that are reproducible, provide consistent results, meet standards for mapping accuracy, and can be implemented from national to pan-tropical levels. Remotely sensed data, supported by ground observations, are crucial to such efforts. Recent developments in global to regional monitoring of forests can contribute to reducing the uncertainties in estimates of emissions from deforestation. Monitoring systems at national levels in developing countries can also benefit from pan-tropical and regional observations, mainly by identifying hot spots of change and prioritizing areas for monitoring at finer spatial scales. A pan-tropical perspective is also required to ensure consistency between different national monitoring systems. Data sources already exist to determine baseline periods in the 1990s as historical reference points. Key requirements for implementing such monitoring programs, both at pan-tropical and at national scales, are international commitment of resources to increase capacity, coordination of observations to ensure pan-tropical coverage, access to free or low-cost data, and standardized, consensus protocols for data interpretation and analysis.

  17. Effects of growth temperature and target material on the growth behavior and electro-optical properties of ZnO:Al films deposited by high-rate steered cathodic arc plasma evaporation

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    ZnO:Al (AZO) films were deposited using high-rate (215 nm/min) steered cathodic arc plasma evaporation with a ceramic AZO target at various deposition temperatures (Td = 80-400 °C). AZO films were also prepared with a Zn-Al target at various Td values for comparison. The high-melting-point (1975 °C) AZO target significantly reduced the droplet size to ∼150 nm. In contrast, opaque Zn-Al microdroplets (several μm) were incorporated into the film deposited using the Zn-Al target. The incorporation of large microdroplets resulted in a rough surface and a nonuniform distribution of film thickness due to the self-shadowing effect. Using a combination of a ceramic AZO target and a steered arc to deposit AZO films significantly reduces the droplet size and maintains a high growth rate. The ratio of c- and a-axes lattice constants (c/a ratio) decreased with increasing Td. A higher c/a ratio facilitates strain relaxation via the formation of basal-plane stacking faults. The Al3+ doping efficiency was improved by increasing Td; however, the Al segregated to the grain boundary at high Td (>300 °C). The films deposited with an AZO target at 200 °C had the highest figure of merit (2.21 × 10-2 Ω-1), with a corresponding average transmittance of 87.7% and resistivity of 5.48 × 10-4 Ω cm.

  18. 3 CFR 8651 - Proclamation 8651 of April 8, 2011. Pan American Day and Pan American Week, 2011

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 3 The President 1 2012-01-01 2012-01-01 false Proclamation 8651 of April 8, 2011. Pan American Day and Pan American Week, 2011 8651 Proclamation 8651 Presidential Documents Proclamations Proclamation 8651 of April 8, 2011 Proc. 8651 Pan American Day and Pan American Week, 2011By the President of...

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

    PubMed

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

    2014-07-17

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

  20. 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

    ... 3 The President 1 2011-01-01 2011-01-01 false Proclamation 8495 of April 9, 2010. Pan American Day and Pan American Week, 2010 8495 Proclamation 8495 Presidential Documents Proclamations Proclamation 8495 of April 9, 2010 Proc. 8495 Pan American Day and Pan American Week, 2010By the President of...

  1. 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.

  2. Vertical counterflow evaporative cooler

    DOEpatents

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

    2005-01-25

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

  3. Evaporative cooling of antiprotons for the production of trappable antihydrogen

    SciTech Connect

    Silveira, D. M.; Cesar, C. L.; Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Ashkezari, M. D.; Hayden, M. E.; Baquero-Ruiz, M.; Chapman, S.; Fajans, J.; Povilus, A.; So, C.; Wurtele, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Madsen, N.; Werf, D. P. van der; Friesen, T.; Hydomako, R.; and others

    2013-03-19

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

  4. 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.

  5. Groundwater Evaporation From a Playa in Spring Valley, Nevada

    NASA Astrophysics Data System (ADS)

    Thomas, J. M.; Deverel, S.; Decker, D. L.; Earman, S.; Mihevc, T.; Acheampong, S.

    2005-12-01

    Bare soil playa evaporation from shallow groundwater is an important discharge component of the groundwater budget for topographically-closed basins in Nevada. However, playa groundwater evaporation is difficult to estimate. Deuterium and oxygen-18 isotopic values and chloride concentrations of soil water were used to estimate groundwater evaporation from the Yelland Playa in Spring Valley, eastern Nevada. The depth distribution of stable isotopes and chloride in soil water beneath the playa surface and the electrical conductivity of the shallow groundwater indicate prolonged evaporation of the shallow groundwater through a dry soil. Analysis of deuterium, oxygen-18 and chloride data produced similar estimated evaporation rates for two sites on the playa. At one site near the edge of the playa, the calculated evaporation rate was 11 to 14 mm/yr; at a second site near the center of the playa, the calculated evaporation rate was 39 to 43 mm/yr. These results indicate that the method is applicable for estimating bare soil evaporation rates for Nevada playas. However, the data collected for this study indicate disequilibrium, especially at the site near the center of the playa. The cause of the apparent disequilibrium is uncertain, but may be the result of declining groundwater levels due to recent drought conditions.

  6. Pan-Arctic multivariate change

    NASA Astrophysics Data System (ADS)

    Overland, J.; Spillane, M.; Soreide, N.

    2003-04-01

    Recent large changes in the Arctic for 1965-1995 are documented through examination of 86 regionally-distributed time series representing seven data types: climate indices, atmosphere, ocean, terrestrial, sea ice, fisheries, and other biological data. These changes are compared with 19th and 20th century temperature records. Although visual inspection of the data collection indicates that Arctic change is complex, two patterns are evident. The pattern based upon the first Principal Component(PC1), representing 23% of the variance, shows an upward trend and has a single regime-like shift near 1989 based on a large number of time series, including projections from a strong stratospheric vortex in spring, the Arctic Oscillation, sea ice declines in several regions, and changes in selected mammal, bird, and fish populations. The pattern based on the second Principal Component(PC2) shows interdecadal variability over the Arctic Ocean Basin north of 70N; this variability is observed in surface wind fields, sea ice, and ocean circulation. Most land processes-such as snow cover, greenness, Siberian runoff, permafrost temperatures-and certain subarctic sea ice records show a linear trend over the 30-year interval that contributes to PC1; these variables are from lower latitudes and often integrate the atmospheric or oceanographic influence over several seasons or years including summer. Century-long surface temperature data support these two patterns with an interdecadal high-latitude/NAO type pattern, and a long-term, pan-Arctic change since the end of the little ice age. That more than half of the data collection projects strongly onto the two patterns, suggests that the Arctic is responding as a coherent system over at least the previous three decades.

  7. 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.

  8. The Pan-STARRS search for Near Earth Objects

    NASA Astrophysics Data System (ADS)

    Wainscoat, Richard J.; Chambers, Kenneth; Lilly, Eva; Weryk, Robert; Chastel, Serge; Denneau, Larry; Micheli, Marco

    2015-11-01

    The two Pan-STARRS telescopes, located on Haleakala, Hawaii, are 1.8-meter diameter telescopes equipped with 1.4 Gigapixel cameras that deliver 7 square degree fields of view. The first telescope, Pan-STARRS1 (PS1), has been conducting a survey for Near-Earth Objects. The second telescope, Pan-STARRS2 (PS2) is nearing completion. The telescope was commissioned using an incomplete focal plane with only 18 good detectors (60 required). The camera is presently being upgraded, and will be operated from October 2015 with 60 detectors (some engineering grade). A final upgrade to the camera in early 2016 will make the telescope fully operational.The two telescopes survey much of the sky accessible from Haleakala multiple times each lunation. The area surveyed ranges from +90 degrees in the north down to -47.5 degrees declination in the south. The “sweet spots” close to the Sun have been productive in discovery of large objects.The PS1 survey is becoming more mature and productive, having discovered more than half of all NEOs in 2015 to date, and more than 60% of the larger NEOs and PHAs discovered in 2015. Both PS1 and PS2 deliver excellent astrometry and photometry. PS1 continues to discover a significant number of large (> 1km) NEOs. PS1 has become the leading discover of comets, discovering more than half of the new comets in both 2014 and 2015.In good weather conditions, the discovery rate of NEO candidates by PS1 overwhelms the external NEO followup resources. particularly for fainter NEOs. As a result, we needed to repeat fields to recover NEO candidates. As PS2 matures, with a complete focal plane, and when the G96 camera upgrade is complete, the combination of these three telescopes will facilitate a higher NEO discovery rate, a better census of the NEOs in the sky, and better orbits for NEOs. This will in turn lead to a better understanding of the size and orbit distribution of NEOs. The Pan-STARRS NEO survey is also likely to discover asteroids suitable for the NASA asteroid retrieval mission.Some early science highlights from the Pan-STARRS survey will be discussed.

  9. Bubble vortex at surfaces of evaporating liquids.

    PubMed

    Yaminsky, V V

    2006-05-01

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

  10. 75 FR 19181 - Pan American Day and Pan American Week, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ... the two hundred and thirty-fourth. (Presidential Sig.) [FR Doc. 2010-8672 Filed 4-13-10; 8:45 am... Documents#0;#0; #0; #0;Title 3-- #0;The President ] Proclamation 8495 of April 9, 2010 Pan American Day and Pan American Week, 2010 By the President of the United States of America A Proclamation More than...

  11. 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.

  12. Monthly evaporation forecasting using artificial neural networks and support vector machines

    NASA Astrophysics Data System (ADS)

    Tezel, Gulay; Buyukyildiz, Meral

    2015-02-01

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

  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. Kepler Planets: A Tale of Evaporation

    NASA Astrophysics Data System (ADS)

    Owen, James E.; Wu, Yanqin

    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 ⊕. Planets that have experienced high X-ray exposures are generally smaller than this size, and those with lower X-ray exposures are typically larger. A bimodal planet size distribution is naturally predicted by the evaporation model, where, depending on their X-ray exposure, close-in planets can either hold on to hydrogen envelopes ~0.5%-1% in mass or be stripped entirely. To quantitatively reproduce the observed features, we argue that not only do low-mass Kepler planets need to be made of rocky cores surrounded with hydrogen envelopes, but few of them should have initial masses above 20 M ⊕ and the majority of them should have core masses of a few Earth masses.

  15. KEPLER PLANETS: A TALE OF EVAPORATION

    SciTech Connect

    Owen, James E.; Wu, Yanqin E-mail: wu@astro.utoronto.ca

    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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  18. Catastrophic evaporation of rocky planets

    NASA Astrophysics Data System (ADS)

    Perez-Becker, Daniel; Chiang, Eugene

    2013-08-01

    Short-period exoplanets can have dayside surface temperatures surpassing 2000 K, hot enough to vaporize rock and drive a thermal wind. Small enough planets evaporate completely. We construct a radiative hydrodynamic model of atmospheric escape from strongly irradiated, low-mass rocky planets, accounting for dust-gas energy exchange in the wind. Rocky planets with masses ≲ 0.1 M⊕ (less than twice the mass of Mercury) and surface temperatures ≳2000 K are found to disintegrate entirely in ≲10 Gyr. When our model is applied to Kepler planet candidate KIC 12557548b - which is believed to be a rocky body evaporating at a rate of dot{M} gtrsim 0.1 M_{{{oplus }}} Gyr-1 - our model yields a present-day planet mass of ≲ 0.02 M⊕ or less than about twice the mass of the Moon. Mass-loss rates depend so strongly on planet mass that bodies can reside on close-in orbits for Gyr with initial masses comparable to or less than that of Mercury, before entering a final short-lived phase of catastrophic mass-loss (which KIC 12557548b has entered). Because this catastrophic stage lasts only up to a few per cent of the planet's life, we estimate that for every object like KIC 12557548b, there should be 10-100 close-in quiescent progenitors with sub-day periods whose hard-surface transits may be detectable by Kepler - if the progenitors are as large as their maximal, Mercury-like sizes (alternatively, the progenitors could be smaller and more numerous). According to our calculations, KIC 12557548b may have lost ˜70 per cent of its formation mass; today we may be observing its naked iron core.

  19. Determining the Inception and Magnitude of Subsurface Evaporation

    NASA Astrophysics Data System (ADS)

    Deol, P. K.; Heitman, J.; Amoozegar, A.; Clayton Field Study Team

    2011-12-01

    Evaporation from an initially wet soil occurs at the soil surface but further drying of surface soil with time results in the formation of a dry surface layer. At this stage, the evaporation front moves from the surface to the subsurface. This phenomenon occurs in a highly dynamic near-surface zone making it very challenging to know the location/depth of the evaporation front and to quantify the subsurface evaporation rate. Recent studies show that subsurface evaporation can be measured using a sensible heat balance approach by accounting for the latent heat flux originating below soil surface which is not taken into account in the traditional surface energy balance equation. The soil sensible energy balance approach has been successfully tested against mass balance for estimating evaporation under steady-state controlled lab conditions, as well as to a limited extent in the field. Limitations of the approach for field conditions include inability of instrumentation to quantify evaporation during the initial shift between surface and subsurface evaporation (i.e. when evaporation occurs at depths shallower than approximately 3 mm). The objectives of this study are to 1) find indicators of the change in the location of the evaporation front from surface to subsurface, and 2) test the sensible heat balance approach for quantifying evaporation from the inception of the subsurface evaporation zone. Recently introduced multi-needle heat pulse probes were used to make continuous soil temperature and thermal property measurements in the near-surface zone at the mm scale in a bare surface soil. Preliminary results from this investigation will be presented.

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

  1. The Pan-STARRS1 Surveys

    NASA Astrophysics Data System (ADS)

    Chambers, Kenneth C.

    2014-01-01

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

  2. An evaporation model of colloidal suspension droplets

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

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

  3. Ten years of pan-genome analyses.

    PubMed

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

    2015-02-01

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

  4. Evaporation Dynamics of Moss and Bare Soil in Boreal Forests

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  5. Single Stage Evaporation of Solar Condensate Dust to Make CAIs

    NASA Astrophysics Data System (ADS)

    Ebel, D. S.; Grossman, L.

    2001-03-01

    Cooling rates and peak T are found, to predict observed chemical and isotopic compositions, and melilite zoning, of Type A and B CAIs, by cooling, evaporating, and crystallizing solar condensate precursors instantly heated in 1 microbar pure H_2.

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1992-02-01

    An investigation of the role of solvent evaporation in tetragonal lysozyme crystallization was preformed with a device that employs N 2(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.

  9. 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.

  10. Electrode evaporation in an arc with pulsing current

    NASA Astrophysics Data System (ADS)

    Nemchinsky, Valerian A.

    1997-10-01

    An explanation of the observed fact that the rate of evaporation of an electrode in the pulsed gas metal arc welding mode decreases when the frequency of pulsing is increased (thus producing less fumes) is presented. The major portion of the total evaporation in the pulsed mode occurs when the surface temperature of the electrode is close to its maximum value. Therefore, all the methods that decrease the maximum value of the surface temperature, such as increase in frequency and choice of the proper current waveform, reduce the fume generation rate. A mathematical model to describe the arc electrode evaporation in the pulsed mode is presented.

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION... water with entrained solids to the waste water system. “Cow water” shall not be used for acidified...

  12. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION... water with entrained solids to the waste water system. “Cow water” shall not be used for acidified...

  13. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION... water with entrained solids to the waste water system. “Cow water” shall not be used for acidified...

  14. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION... water with entrained solids to the waste water system. “Cow water” shall not be used for acidified...

  15. 7 CFR 58.217 - Evaporators and/or vacuum pans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION... water with entrained solids to the waste water system. “Cow water” shall not be used for acidified...

  16. Barbecued, Pan-Fried Meat May Boost Kidney Cancer Risk

    MedlinePLUS

    ... 155613.html Barbecued, Pan-Fried Meat May Boost Kidney Cancer Risk High-heat cooking methods implicated in ... or pan-frying, may increase the risk for kidney cancer, a new study suggests. The World Health ...

  17. Rotatable prism for pan and tilt

    NASA Technical Reports Server (NTRS)

    Ball, W. B.

    1980-01-01

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

  18. THE Pan-STARRS1 PHOTOMETRIC SYSTEM

    SciTech Connect

    Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Morgan, J. S.; Wainscoat, R. J.; Stubbs, C. W.; Shivvers, I. S.; Lykke, K. R.; Doherty, P.; Price, P. A.

    2012-05-10

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

  19. Imitation in Neonatal Chimpanzees ("Pan Troglodytes")

    ERIC Educational Resources Information Center

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

    2004-01-01

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

  20. 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.

  1. Evaporation and skin penetration characteristics of mosquito repellent formulations

    SciTech Connect

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

    1989-03-01

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

  2. Crystallization of proteins by dynamic control of evaporation

    NASA Astrophysics Data System (ADS)

    Wilson, L. G.; Bray, T. L.; Suddath, F. L.

    1991-03-01

    It is expected that the kinetics of supersaturation, which is directly related to the evaporation of solvent from a crystallization solution, will greatly affect both nucleation and crystal growth processes. Therefore, a novel device has been developed which allows computer regulation of the flow of N 2(g) over a hanging drop to dynamically control the evaporation of solvent. A thermal conductivity detector is used to monitor the amount of water vapor transferred from the drop to the gas stream and provides closed loop control of the evaporation process. Data acquisition and control are accomplished using a custom program written with LabVIEW software (National Instruments) on a Macintosh II microcomputer. Quantitation of several evaporation protocols has been accomplished using both the thermal conductivity detector and a novel conductance cell that allows continuous measurement of solution analyte concentrations. Crystals of hen egg white lysozyme have been grown at different evaporation rates and analyzed according to size and number of single crystals.

  3. Evaporative cooling of the dipolar hydroxyl radical.

    PubMed

    Stuhl, Benjamin K; Hummon, Matthew T; Yeo, Mark; Qumner, Goulven; Bohn, John L; Ye, Jun

    2012-12-20

    Atomic physics was revolutionized by the development of forced evaporative cooling, which led directly to the observation of Bose-Einstein condensation, quantum-degenerate Fermi gases and ultracold optical lattice simulations of condensed-matter phenomena. More recently, substantial progress has been made in the production of cold molecular gases. Their permanent electric dipole moment is expected to generate systems with varied and controllable phases, dynamics and chemistry. However, although advances have been made in both direct cooling and cold-association techniques, evaporative cooling has not been achieved so far. This is due to unfavourable ratios of elastic to inelastic scattering and impractically slow thermalization rates in the available trapped species. Here we report the observation of microwave-forced evaporative cooling of neutral hydroxyl (OH()) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least one order of magnitude in temperature, and a corresponding increase in phase-space density by three orders of magnitude, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique. With evaporative cooling and a sufficiently large initial population, much colder temperatures are possible; even a quantum-degenerate gas of this dipolar radical (or anything else it can sympathetically cool) may be within reach. PMID:23257881

  4. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  5. Student-Centered Designs of Pan-African Literature Courses

    ERIC Educational Resources Information Center

    M'Baye, Babacar

    2010-01-01

    A student-centered teaching methodology is an essential ingredient of a successful Pan-African literary course. In this article, the author defines Pan-Africanism and how to go about designing a Pan-African literature course. The author combines reading assignments with journals, film presentations, and lectures in a productive learning

  6. 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)

  7. Vacuum flash evaporated polymer composites

    DOEpatents

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

    1997-01-01

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

  8. Vacuum flash evaporated polymer composites

    DOEpatents

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

    1997-10-28

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

  9. 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.

  10. 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.

  11. Molecular Mechanism of Water Evaporation

    NASA Astrophysics Data System (ADS)

    Nagata, Yuki; Usui, Kota; Bonn, Mischa

    2015-12-01

    Evaporation is the process by which water changes from a liquid to a gas or vapor, and is a key step in Earth's water cycle. At the molecular level, evaporation requires breaking at least one very strong intermolecular bond between two water molecules at the interface. Despite the importance of this process the molecular mechanism by which an evaporating water molecule gains sufficient energy to escape from the surface has remained elusive. Here, we show, using molecular dynamics simulations at the water-air interface with polarizable classical force field models, that the high kinetic energy of the evaporated water molecule is enabled by a well-timed making and breaking of hydrogen bonds involving at least three water molecules at the interface, the recoil of which allows one of the molecules to escape. The evaporation of water is thus enabled by concerted, ultrafast hydrogen-bond dynamics of interfacial water, and follows one specific molecular pathway.

  12. Molecular Mechanism of Water Evaporation.

    PubMed

    Nagata, Yuki; Usui, Kota; Bonn, Mischa

    2015-12-01

    Evaporation is the process by which water changes from a liquid to a gas or vapor, and is a key step in Earth's water cycle. At the molecular level, evaporation requires breaking at least one very strong intermolecular bond between two water molecules at the interface. Despite the importance of this process the molecular mechanism by which an evaporating water molecule gains sufficient energy to escape from the surface has remained elusive. Here, we show, using molecular dynamics simulations at the water-air interface with polarizable classical force field models, that the high kinetic energy of the evaporated water molecule is enabled by a well-timed making and breaking of hydrogen bonds involving at least three water molecules at the interface, the recoil of which allows one of the molecules to escape. The evaporation of water is thus enabled by concerted, ultrafast hydrogen-bond dynamics of interfacial water, and follows one specific molecular pathway. PMID:26684127

  13. Pan-Planets: Searching for hot Jupiters around cool dwarfs

    NASA Astrophysics Data System (ADS)

    Obermeier, C.; Koppenhoefer, J.; Saglia, R. P.; Henning, Th.; Bender, R.; Kodric, M.; Deacon, N.; Riffeser, A.; Burgett, W.; Chambers, K. C.; Draper, P. W.; Flewelling, H.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Metcalfe, N.; Price, P. A.; Sweeney, W.; Wainscoat, R. J.; Waters, C.

    2016-03-01

    The Pan-Planets survey observed an area of 42 sq deg. in the galactic disk for about 165 h. The main scientific goal of the project is the detection of transiting planets around M dwarfs. We establish an efficient procedure for determining the stellar parameters Teff and log g of all sources using a method based on SED fitting, utilizing a three-dimensional dust map and proper motion information. In this way we identify more than 60 000 M dwarfs, which is by far the largest sample of low-mass stars observed in a transit survey to date. We present several planet candidates around M dwarfs and hotter stars that are currently being followed up. Using Monte Carlo simulations we calculate the detection efficiency of the Pan-Planets survey for different stellar and planetary populations. We expect to find 3.0+3.3-1.6 hot Jupiters around F, G, and K dwarfs with periods lower than 10 days based on the planet occurrence rates derived in previous surveys. For M dwarfs, the percentage of stars with a hot Jupiter is under debate. Theoretical models expect a lower occurrence rate than for larger main sequence stars. However, radial velocity surveys find upper limits of about 1% due to their small sample, while the Kepler survey finds a occurrence rate that we estimate to be at least 0.17b(+0.67-0.04) %, making it even higher than the determined fraction from OGLE-III for F, G and K stellar types, 0.14 (+0.15-0.076) %. With the large sample size of Pan-Planets, we are able to determine an occurrence rate of 0.11 (+0.37-0.02) % in case one of our candidates turns out to be a real detection. If, however, none of our candidates turn out to be true planets, we are able to put an upper limit of 0.34% with a 95% confidence on the hot Jupiter occurrence rate of M dwarfs. This limit is a significant improvement over previous estimates where the lowest limit published so far is 1.1% found in the WFCAM Transit Survey. Therefore we cannot yet confirm the theoretical prediction of a lower occurrence rate for cool stars. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  14. An evaporation model of multicomponent solution drops

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  15. 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

  16. 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.

  17. The Evaporative Function of Cockroach Hygroreceptors

    PubMed Central

    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

  18. 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

  19. 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.

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

    USGS Publications Warehouse

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

    2000-01-01

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

  1. PAN/PS elctrospun fibers for oil spill cleanup

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  2. Externally Induced Evaporation of Young Stellar Disks in Orion

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  3. 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.

  4. ENSO and multi-decadal 'trends' in continental evaporation

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  5. Tracking of flying insects using pan-tilt cameras.

    PubMed

    Fry, S N; Bichsel, M; Mller, P; Robert, D

    2000-08-15

    Potent and affordable video and computer systems for automatic data acquisition are becoming increasingly important in behavioural neuroscience. It has remained challenging, however, to acquire data from small and fast-moving animals, such as insects in flight, due to the limited spatial and temporal resolution of the systems currently available. Our research on free-flying insects motivated the development of new methods in the context of two different experimental settings. First, the position and precise body axis direction of honey bees approaching a food source were automatically measured. Second, the flight trajectories of a phonotactic parasitoid fly homing in on its cricket host were recorded in 3D. We used pan-tilt cameras, i.e. cameras with moveable optics, to follow the animal's path with a close up image. Novel methods were developed for image acquisition and position measurement using pan-tilt cameras, as well as calibration and data evaluation in 3D world coordinates. The innovations of this system comprise: (1) Acquisition of images in high spatial detail over large observation areas. (2) Image acquisition at a field rate of 50 Hz PAL. (3) Free positioning of the cameras for 3D acquisition. (4) Computation of the flight path in 3D world coordinates. We illustrate the capabilities of the system with data obtained from a calibration object as well as from the behaviour of unrestricted, free-flying flies and bees. Potential applications in behavioural neuroscience and the psychophysics of sensory perception are briefly discussed. PMID:10967362

  6. 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.

  7. Trends in evaporation and surface cooling in the Mississippi River basin

    USGS Publications Warehouse

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

    2001-01-01

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

  8. 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

  9. 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.

  10. Electron Forced Evaporative Cooling in Ultracold Plasmas

    NASA Astrophysics Data System (ADS)

    Witte, Craig; Roberts, Jacob

    2015-05-01

    Ultracold plasmas (UCPs) are formed by photoionizing a collection of laser cooled atoms. Once formed, these plasmas expand, cooling over the course of their expansion. In theory, further cooling should be obtainable by forcibly inducing electron evaporation through applying DC electric fields to extract electrons. However, for many UCP parameters, UCP electrons are not fully thermalized until very late in the expansion. This creates complications in analyzing the UCP. This problem can be remedied by creating the ultracold plasma at substantially lower initial temperatures since thermalization rates increase with decreasing temperature. Unfortunately, traditional models of UCP dynamics tend to break down in cases of substantial non-neutrality when used in the limit of zero temperature. We have developed a theoretical model that calculates potential depth and expansion dynamics of non-neutral UCPs in the limit of zero temperature. Such a model will allow us to quantify the degree of cooling obtained by evaporation as measured experimentally. Supported by the AFOSR.

  11. 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.

  12. 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.

  13. 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.

  14. How do Black Holes evaporate?

    NASA Astrophysics Data System (ADS)

    Balbinot, Roberto

    1984-03-01

    The study of a two dimensional model suggests the possibility that Black Hole evaporation may become a dynamically driven process even before Planck era is reached. On leave from the Department of Physics, University of Bologna, Italy.

  15. 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.

  16. Characterization of probiotic Escherichia coli isolates with a novel pan-genome microarray

    PubMed Central

    Willenbrock, Hanni; Hallin, Peter F; Wassenaar, Trudy M; Ussery, David W

    2007-01-01

    Background Microarrays have recently emerged as a novel procedure to evaluate the genetic content of bacterial species. So far, microarrays have mostly covered single or few strains from the same species. However, with cheaper high-throughput sequencing techniques emerging, multiple strains of the same species are rapidly becoming available, allowing for the definition and characterization of a whole species as a population of genomes - the 'pan-genome'. Results Using 32 Escherichia coli and Shigella genome sequences we estimate the pan- and core genome of the species. We designed a high-density microarray in order to provide a tool for characterization of the E. coli pan-genome. Technical performance of this pan-genome microarray based on control strain samples (E. coli K-12 and O157:H7) demonstrated a high sensitivity and relatively low false positive rate. A single-channel analysis approach is robust while allowing the possibility for deriving presence/absence predictions for any gene included on our pan-genome microarray. Moreover, the array was highly sufficient to investigate the gene content of non-pathogenic isolates, despite the strong bias towards pathogenic E. coli strains that have been sequenced so far. Conclusion This high-density microarray provides an excellent tool for characterizing the genetic makeup of unknown E. coli strains and can also deliver insights into phylogenetic relationships. Its design poses a considerably larger challenge and involves different considerations than the design of single strain microarrays. Here, lessons learned and future directions will be discussed in order to optimize design of microarrays targeting entire pan-genomes. PMID:18088402

  17. 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.

  18. Marangoni instability induced convection in an evaporating liquid droplet

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  19. 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.

  20. On the inherent asymmetric nature of the complementary relationship of evaporation

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef

    2007-01-01

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

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

    PubMed

    Myers Thompson, Jo A

    2003-04-01

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

  2. DWPF Recycle Evaporator Simulant Tests

    SciTech Connect

    Stone, M

    2005-04-05

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

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

    2014-03-01

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

  5. Evaporation from a semi-infinite porous medium: The role of capillary flow

    NASA Astrophysics Data System (ADS)

    Navaz, H. K.; Markicevic, B.; Paikoff, S. J.

    2011-11-01

    The liquid evaporation from the semi-infinite porous medium is solved numerically using the dynamic capillary network model in which the interface shape and multiphase flow front thickness between dry and fully wet parts of porous medium are tracked in time. Both convective and diffusion mass transport limited regimes are identified and liquid pseudo-velocity due to the evaporation is calculated. The numerical analysis is extended for in-parallel capillary flow and evaporation liquid transport, and again, the changes of the interface shape and multiphase flow front thickness are investigated. It turns out that the convective evaporation is prolonged due to the capillary flow as evaporated liquid close to the evaporating boundary is replenished by capillary flow. However, the evaporation curve has an elongated ``tail'' for longer evaporation times as capillarity tends to transport the liquid deeper into the porous medium. The contributions of the capillary flow and the mass transport on the overall evaporation dynamics is best visible by comparing the liquid pseudo-velocity for pure evaporation and evaporation with capillary flow. Two pseudo-velocities are equal for time for which there is a transition from convection to diffusion controlled evaporation. In this point, the remaining liquid is always distributed in the multiphase pattern, where the thickness of the multiphase region depends on capillary flow and mass transport rates.

  6. Evaporation Kinetics of Laboratory Generated Secondary Organic Aerosols at Elevated Relative Humidity

    SciTech Connect

    Wilson, Jacqueline M.; Imre, D.; Beranek, Josef; Shrivastava, ManishKumar B.; Zelenyuk, Alla

    2015-01-06

    Secondary organic aerosols (SOA) dominate atmospheric organic aerosols that affect climate, air quality, and health. Recent studies indicate that, contrary to previously held assumptions, at low relative humidity (RH) these particles are semi-solid and evaporate orders of magnitude slower than expected. Elevated relative humidity has the potential to affect significantly formation, properties, and atmospheric evolution of SOA particles. Here we present a study of the effect of RH on the room-temperature evaporation kinetics of SOA particles formed by ozonolysis of α-pinene and limonene. Experiments were carried out on SOA particles generated, evaporated, and aged at 0%, 50% and 90% RH. We find that in all cases evaporation begins with a relatively fast phase, during which 30% to 70% of the particle mass evaporates in 2 hours, followed by a much slower evaporation rate. Evaporation kinetics at 0% and 50% RH are nearly the same, while at 90% RH a slightly larger fraction evaporates. In all cases, aging the particles prior to inducing evaporation reduces the evaporative losses, with aging at elevated RH leading to more significant effect. In all cases, SOA evaporation is nearly size-independent, providing direct evidence that oligomers play a crucial role in determining the evaporation kinetics.

  7. ENSO and Multi-Decadal 'trends' in Terrestrial Evaporation

    NASA Astrophysics Data System (ADS)

    Miralles, D. G.; de Jeu, R.; Verhoest, N.; Teuling, R.; Gash, J.; van Den Berg, M. J.; Nieto, R. O.; Gimeno, L.; Dorigo, W.; Parinussa, R.; Holmes, T. R.; Jimenez, C.; Beck, H.; Dolman, A. J.

    2014-12-01

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

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

    SciTech Connect

    Not Available

    1993-02-01

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

  9. EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS

    SciTech Connect

    Tanaka, Kyoko K.; Yamamoto, Tetsuo; Tanaka, Hidekazu; Miura, Hitoshi; Nagasawa, Makiko; Nakamoto, Taishi

    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.

  10. 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.

  11. Star Formation Histories from Pan-Chromatic Infrared Continuum Surveys

    NASA Astrophysics Data System (ADS)

    Molinari, Sergio

    2010-11-01

    One of the currently most disputed issues in Star Formation is the timeline of the whole process. Is it a slow process of cloud assembly which, mediated by magnetic fields, evolve toward turbulence-supported clumps which are eventually super-critical to collapse, e.g. McKee & Tan (2003)? Or do clumps originate in already super-critical state in the post-shock regions of large-scale Galactic converging flows, e.g. Hartmann et al. (2001) with a rapid collapse in a crossing time or so (Elmegreen 2000)? A pan-chromatic 1?m-1mm continuum view of cluster forming regions in their early stages offers access to the most massive members longward of 5-10?m, as well as the low-mass members which instead dominate the emission in the near-IR, offering an interesting potential in stimulating advances in theoretical modelling of clustered star formation, its history and rate.

  12. Stick-Jump (SJ) Evaporation of Strongly Pinned Nanoliter Volume Sessile Water Droplets on Quick Drying, Micropatterned Surfaces.

    PubMed

    Debuisson, Damien; Merlen, Alain; Senez, Vincent; Arscott, Steve

    2016-03-22

    We present an experimental study of stick-jump (SJ) evaporation of strongly pinned nanoliter volume sessile water droplets drying on micropatterned surfaces. The evaporation is studied on surfaces composed of photolithographically micropatterned negative photoresist (SU-8). The micropatterning of the SU-8 enables circular, smooth, trough-like features to be formed which causes a very strong pinning of the three phase (liquid-vapor-solid) contact line of an evaporating droplet. This is ideal for studying SJ evaporation as it contains sequential constant contact radius (CCR) evaporation phases during droplet evaporation. The evaporation was studied in nonconfined conditions, and forced convection was not used. Micropatterned concentric circles were defined having an initial radius of 1000 μm decreasing by a spacing ranging from 500 to 50 μm. The droplet evaporates, successively pinning and depinning from circle to circle. For each pinning radius, the droplet contact angle and volume are observed to decrease quasi-linearly with time. The experimental average evaporation rates were found to decrease with decreasing pining radii. In contrast, the experimental average evaporation flux is found to increase with decreasing droplet radii. The data also demonstrate the influence of the initial contact angle on evaporation rate and flux. The data indicate that the total evaporation time of a droplet depends on the specific micropattern spacing and that the total evaporation time on micropatterned surfaces is always less than on flat, homogeneous surfaces. Although the surface patterning is observed to have little effect on the average droplet flux-indicating that the underlying evaporation physics is not significantly changed by the patterning-the total evaporation time is considerably modified by patterning, up to a factor or almost 2 compared to evaporation on a flat, homogeneous surface. The closely spaced concentric circle pinning maintains a large droplet radius and small contact angle from jump to jump; the result is a large evaporation rate leading to faster evaporation. PMID:26950673

  13. 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

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

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

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

  15. 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.

  16. Global sources and significance of peroxyacetyl nitrate (PAN)

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Evaporation of volatile organic compounds from human skin in vitro.

    PubMed

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

    2013-08-01

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

  18. Slow-blue PanSTARRS transients

    NASA Astrophysics Data System (ADS)

    MacLeod, Chelsea L.; Bruce, Alastair; Lawrence, Andy; Ward, Martin; Collinson, James; Elvis, Martin; Gezari, Suvi; Smartt, Steven; Smith, Ken; Wright, Darryl; Fraser, Morgan

    2015-01-01

    Photometric and spectroscopic monitoring of 50 blue, nuclear "transients" in PanSTARRS-1 has revealed different types of extremely variable AGN. The majority show a gradual brightening by ~2 mag from the SDSS observation a decade ago and may represent a new class of AGN microlensed by foreground galaxies. Spectra from the William Herschel Telescope identify these as z~1 AGN with atypical spectroscopic properties. We present an analysis of their photometric and spectroscopic variability in an effort to constrain the detailed structure of the source AGN.

  19. Studbook of Pan paniscus Schwarz, 1929.

    PubMed

    Guzen, A

    1975-01-01

    On the basis of information provided by various zoos who have, or used to have, Pan paniscus in their collections, as well as information in the International Zoo Yearbook or in the literature, an approximate outline has been given of our knowledge of this animal since the description given in 1929 by Schwarz. The status of species is preferred to that of subspecies. The question whether the bonobo should be regarded as a true dwarf form is considered. It is, however, emphasized that the majority of researchers - and for different reasons - consider the species to be the primate closest to man. PMID:1163394

  20. 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

  1. 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.

  2. 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

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

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Gonzalez, Mark A.

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

  5. Modeling of two-layer liquid-gas flow with account for evaporation

    NASA Astrophysics Data System (ADS)

    Goncharova, O. N.; Rezanova, E. V.; Lyulin, Yu. V.; Kabov, O. A.

    2015-09-01

    Two-layer gas-liquid flows and evaporation intensity at the interface were studied. The influence of gas flow rate, longitudinal gradient of temperature, the Soret effect on the nature of flow and transfer processes was demonstrated. Experimental and theoretical results were compared; they show dependence of evaporation at the interface on gas flow rates.

  6. Control methods and systems for indirect evaporative coolers

    SciTech Connect

    Woods, Jason; Kozubal, Erik

    2015-09-22

    A control method for operating an indirect evaporative cooler to control temperature and humidity. The method includes operating an airflow control device to provide supply air at a flow rate to a liquid desiccant dehumidifier. The supply air flows through the dehumidifier and an indirect evaporative cooler prior to exiting an outlet into a space. The method includes operating a pump to provide liquid desiccant to the liquid desiccant dehumidifier and sensing a temperature of an airstream at the outlet of the indirect evaporative cooler. The method includes comparing the temperature of the airstream at the outlet to a setpoint temperature at the outlet and controlling the pump to set the flow rate of the liquid desiccant. The method includes sensing space temperature, comparing the space temperature with a setpoint temperature, and controlling the airflow control device to set the flow rate of the supply air based on the comparison.

  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. Characteristics and treatment outcomes of pan-urothelial cell carcinoma: a descriptive analysis of 45 patients.

    PubMed

    Fang, Dong; Liu, Pei; Li, Xuesong; Xiong, Gengyan; Zhang, Lei; Singla, Nirmish; Zhao, Guangzhi; He, Qun; He, Zhisong; Zhou, Liqun

    2015-01-01

    The incidence of pan-urothelial cell carcinoma (panUCC), which refers to the presence of both bilateral (UTUC) and bladder tumor (BT), is relatively low. However, the profile of a panUCC cohort of patients remains to be elucidated. We reviewed the data of consecutive UTUC patients who received treatment at our center from 1999 to 2012. Overall, 45 patients were included in this study, with a median age of 64.5 years. Fourteen patients initially presented with unilateral UTUC, 11 initially with BT, and the remainder with multiple tumors. Patients with UTUC were more likely to manifest higher rates of muscle invasion and larger-sized tumors. Five patients were treated with complete urinary tract exenteration (CUTE), and most patients (73.3%) received combined management with conservative and radical surgery. After a median follow-up of 77 months, 18 patients (40%) died including 15 (33.3%) due to cancer. Higher tumor stage was the only risk factor predictive of worse survival. Nineteen patients experienced local recurrence after conservative surgery. This study indicated that PanUCC involves either synchronous or metachronous presentation of tumors with a high risk of tumor recurrence, progression, and dissemination after conservative surgery. PMID:26657777

  9. Characteristics and treatment outcomes of pan-urothelial cell carcinoma: a descriptive analysis of 45 patients

    PubMed Central

    Fang, Dong; Liu, Pei; Li, Xuesong; Xiong, Gengyan; Zhang, Lei; Singla, Nirmish; Zhao, Guangzhi; He, Qun; He, Zhisong; Zhou, Liqun

    2015-01-01

    The incidence of pan-urothelial cell carcinoma (panUCC), which refers to the presence of both bilateral (UTUC) and bladder tumor (BT), is relatively low. However, the profile of a panUCC cohort of patients remains to be elucidated. We reviewed the data of consecutive UTUC patients who received treatment at our center from 1999 to 2012. Overall, 45 patients were included in this study, with a median age of 64.5 years. Fourteen patients initially presented with unilateral UTUC, 11 initially with BT, and the remainder with multiple tumors. Patients with UTUC were more likely to manifest higher rates of muscle invasion and larger-sized tumors. Five patients were treated with complete urinary tract exenteration (CUTE), and most patients (73.3%) received combined management with conservative and radical surgery. After a median follow-up of 77 months, 18 patients (40%) died including 15 (33.3%) due to cancer. Higher tumor stage was the only risk factor predictive of worse survival. Nineteen patients experienced local recurrence after conservative surgery. This study indicated that PanUCC involves either synchronous or metachronous presentation of tumors with a high risk of tumor recurrence, progression, and dissemination after conservative surgery. PMID:26657777

  10. Tubular sublimatory evaporator heat sink

    NASA Technical Reports Server (NTRS)

    Webbon, B. W. (inventor)

    1977-01-01

    An evaporative refrigerator or cooler comprising a bundle of spaced, porous walled tubes closed at one of their ends and vented to a vacuum at the other end is disclosed. The tube bundle is surrounded by a water jacket having a hot water inlet distribution manifold and a cooled water outlet through a plenum chamber. Hot water is pumped into the jacket to circulate around the tubes, and when this water meets the vacuum existing inside the tubes, it evaporates thereby cooling the water in the jacket. If cooling proceeds to the point where water penetrating or surrounding all or part of the tubes freezes, operation continues with local sublimation of the ice on the tubes while the circulating water attempts to melt the ice. Both sublimation and evaporation may take place simultaneously in different regions of the device.

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

    NASA Astrophysics Data System (ADS)

    Maurer, T.

    2013-05-01

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

  12. 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.

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

    PubMed

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

    2008-09-01

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

  14. Effect of soil property on evaporation from bare soils

    NASA Astrophysics Data System (ADS)

    Zhang, Chenming; Li, Ling; Lockington, David

    2015-04-01

    Quantifying the actual evaporation rate from bare soils remains a challenging task as it not only associates with the atmospheric demand and liquid water saturation on the soil surface, but also the properties of the soils (e.g., porosity, pore size distribution). A physically based analytical model was developed to describe the surface resistance varying with the liquid water saturation near the soil surface. This model considers the soil pore size distribution, hydraulic connection between the main water cluster and capillary water in the soil surface when the soil surface is wet and the thickness of the dry soil layer when the soil surface is dry. The surface resistance model was then integrated to a numerical model based on water balance, heat balance and surface energy balance equations. The integrated model was validated by simulating water and heat transport processes during six soil column drying experiments. The analysis indicates that the when soil surface is wet, the consideration of pore size distribution in the surface resistance model offers better estimation of transient evaporation among different soil types than the estimations given by empirically based surface resistance models. Under fixed atmospheric boundary condition and liquid water saturation, fine sand has greater evaporation rate than coarse sand as stronger capillary force devlivers more water from the main water cluster. When the soil surface becomes dry, the impact of soil property to evaporation becomes trivial as the thickness of the dry soil layer turns to be the key factor to determine the evaporation rate.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  16. Evaporation control research, 1959-60

    USGS Publications Warehouse

    U.S. Geological Survey

    1963-01-01

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

  17. Design and development of a split-evaporator heat-pump system

    NASA Astrophysics Data System (ADS)

    Somerville, M. H.; Penoncello, S. G.

    1981-12-01

    Three types of multiple source heat pumps are presented. The three designs are the parallel evaporator, the series evaporator, and the parallel evaporator with active subcooling, with the parallel evaporator with the active subcooling showing the most promise for solving the problem of defrosting of air evaporators. The models are based upon the refrigerant flow rate, rather than the refrigeration effect of the evaporator. It is shown that the temperature of the air surrounding the flat plate ice maker plays a dominant role in the rate of ice formation. A weather analysis for forty cities throughout the nation was completed. These data were processed to allow easy computation of thermal storage requirements, such as off peak air conditioning. The results of an ice storage system that is thermally coupled to the Earth are described. An economic and energy comparison of multiple source heat pumps with ACES, and air-to-air heat pump systems is presented.

  18. Understanding the Pan Asian Client: A Handbook for Helping Professionals.

    ERIC Educational Resources Information Center

    Union of Pan Asian Communities, San Diego, CA.

    This booklet provides background information and suggestions to those who find themselves providing human care services to Pan Asian clients (Cambodians, Chinese, Guamanians, Hawaiians, Japanese, Koreans, Laotians, Pilipinos, Samoans, Thais, Vietnamese). Included is historical, cultural, and social information about the various Pan Asian groups in

  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. 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.

  1. Simulation of a refrigerant evaporator

    NASA Astrophysics Data System (ADS)

    Vandermeer, Jakob Stefanus

    A computer model for the design and optimization of the compressor refrigeration cycle especially with respect to dynamic behavior was developed. A steady state version was also developed. The model describing the refrigerant is divided into the evaporation and superheating regions. A mechanism based on empirics corrects the model for the influence of transportation times in the evaporation region. The mass balance of the refrigerant in the superheat region is regarded as quasi-static, because of the small mass of the vapor. The energy balance accounts for a distributed model and is represented by the steady state solution of the partial differential equation which describes this area for the steady conditions. A correction for the dynamical effects was added to this solution, for all influencing parameters, according to the analytical dynamic solution for the case of the evaporation temperature as input parameter. The expansion device model was worked out for the usual type of device in combination with a dry evaporator, the thermostatic expansion valve. Validation tests are described.

  2. 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.

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

    SciTech Connect

    Jiang, Yi; Xie, Xiaoyun

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  6. Transpiration and evaporation from heather Moorland

    NASA Astrophysics Data System (ADS)

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

    1984-03-01

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

  7. The Pan-STARRS search for Near Earth Objects

    NASA Astrophysics Data System (ADS)

    Wainscoat, Richard; Chambers, Ken; Lilly, Eva; Weryk, Robert; Chastel, Serge; Denneau, Larry; Micheli, Marco

    2016-01-01

    The two Pan-STARRS telescopes, located on Haleakala, Maui, Hawaii, are 1.8-meter diameter telescopes equipped with 1.4 Gigapixel cameras that deliver 7 square degree fields-of-view. The first of these telescopes, Pan-STARRS1, is conducting a search for Near Earth Objects, and is currently the leading discoverer of Near Earth Objects. The second telescope, Pan-STARRS2, is nearing the end of its commissioning, and is becoming more productive. Pan-STARRS has become the leading survey for Near Earth Objects, responsible for approximately half of the NEO discoveries to date in 2015. Pan-STARRS is also the leading discoverer of new comets.

  8. Correlations for Saturation Efficiency of Evaporative Cooling Pads

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Leeper, R. D.; Kochendorfer, J.

    2014-12-01

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

  11. Water addition, evaporation and water holding capacity of poultry litter.

    PubMed

    Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

    2015-12-15

    Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis. PMID:26367067

  12. Piagetian liquid conservation in the great apes (Pan paniscus, Pan troglodytes, and Pongo pygmaeus).

    PubMed

    Suda, Chikako; Call, Josep

    2004-09-01

    An understanding of Piagetian liquid conservation was investigated in 4 bonobos (Pan paniscus), 5 chimpanzees (Pan troglodytes), and 5 orangutans (Pongo pygmaeus). The apes were tested in the ability to track the larger of 2 quantities of juice that had undergone various kinds of transformations. The accuracy of the apes' judgment depended on the shape or number of containers into which the larger quantity was transferred. The apes made their choice mainly on the basis of visual estimation but showed modest success when the quantities were occluded. The results suggest that the apes rely to a greater extent on visual information, although they might have some appreciation of the constancy of liquid quantities. PMID:15482054

  13. Studies for the staggered pans core catcher

    SciTech Connect

    Fieg, G.; Moeschke, M.; Werle, H.

    1995-09-01

    Special devices (core catchers) might be required in the future to prevent containment failure by basemat erosion after reactor pressure vessel melt-through during a core meltdown accident. Quick freezing of the molten core masses is desirable to reduce the release of radioactivity. A configuration is investigated that consists essentially of a stack of vertically superimposed melt-resistant ceramic pans and that makes use of the vertical extension of small-diameter cavities to provide a sufficiently large spreading area such that the core melt freezes quickly. Tests with {approximately}100 kg of molten iron and aluminium oxide generated by the thermite reaction give some information on the resistance of various materials against the mixed metal/oxide melt and on the flow and distribution of metallic and oxide melts in such a core-catcher configuration.

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

    USGS Publications Warehouse

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

    2006-01-01

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

  15. Instability of evaporation fronts in the interstellar medium

    SciTech Connect

    Kim, Jeong-Gyu; Kim, Woong-Tae E-mail: wkim@astro.snu.ac.kr

    2013-12-10

    The neutral component of the interstellar medium is segregated into the cold neutral medium (CNM) and warm neutral medium (WNM) as a result of thermal instability. It was found that a plane-parallel CNM-WNM evaporation interface, across which the CNM undergoes thermal expansion, is linearly unstable to corrugational disturbances, in complete analogy with the Darrieus-Landau instability (DLI) of terrestrial flames. We perform a full linear stability analysis as well as nonlinear hydrodynamic simulations of the DLI of such evaporation fronts in the presence of thermal conduction. We find that the DLI is suppressed at short length scales by conduction. The length and time scales of the fastest growing mode are inversely proportional to the evaporation flow speed of the CNM and its square, respectively. In the nonlinear stage, the DLI saturates to a steady state where the front deforms to a finger-like shape protruding toward the WNM, without generating turbulence. The evaporation rate at nonlinear saturation is larger than the initial plane-parallel value by a factor of ?2.4 when the equilibrium thermal pressure is 1800 k {sub B} cm{sup 3} K. The degrees of front deformation and evaporation-rate enhancement at nonlinear saturation are determined primarily by the density ratio between the CNM and WNM. We demonstrate that the Field length in the thermally unstable medium should be resolved by at least four grid points to obtain reliable numerical outcomes involving thermal instability.

  16. Public Release of Pan-STARRS Data

    NASA Astrophysics Data System (ADS)

    Flewelling, Heather; Consortium, panstarrs

    2015-08-01

    Pan-STARRS 1 is a 1.8 meter survey telescope, located on Haleakala, Hawaii, with a 1.4 Gigapixel camera, a 7 square degree field of view, and 5 filters (g,r,i,z,y). The public release of data, which is available to everyone, consists of 4 years of data taken between May 2010 and April 2014. Two of the surveys available in the public release are the 3pi survey and the Medium Deep (MD) survey. The 3pi survey has roughly 60 epochs (12 per filter) covering 3/4 of the sky and everything north of -30 degrees declination. The MD survey consists of 10 fields, observed in a couple of filters each night, usually 8 exposures per filter per field, for about 4000 epochs per MD field. The available data product are accessed through the “Postage Stamp Server” and through the Published Science Products Subsystem (PSPS), both of these are available through the Pan-STARRS Science Interface (PSI). The Postage Stamp Server provides images and catalogs for different stages of processing on single exposures, stack images, difference images, and forced photometry. The PSPS is a SQLServer database that can be queried via script or web interface, with a database for each MD field and a large database for the 3pi survey. This database has relative photometry and astrometry and object associations, making it easy to do searches across the entire sky as well as tools to generate lightcurves of individual objects as a function of time.

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

    PubMed Central

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

    2015-01-01

    Abstract 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

  18. 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 δ18O, 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. 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

  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. Modelling evaporation fronts with reactive Riemann solvers

    SciTech Connect

    Le Metayer, O. . E-mail: olivier.lemetayer@polytech.univ-mrs.fr; Massoni, J. . E-mail: jacques.massoni@polytech.univ-mrs.fr; Saurel, R. . E-mail: richard.saurel@polytech.univ-mrs.fr

    2005-05-20

    This work deals with the modelling of permeable fronts and the building of a numerical method allowing the multi-dimensional propagation of such fronts. A particular attention is given to evaporation waves that appear in cavitating systems. These ones are considered as discontinuities through which a non-equilibrium liquid turns to a liquid-vapor mixture at thermodynamic equilibrium. Such transformation occurs at finite rate. In order to determine this kinetics, the evaporation front is assumed to propagate at the maximum admissible speed corresponding to the Chapman-Jouguet deflagration point [J.R., Simoes-Moreira, J.E., Shepherd, Evaporation waves in superheated dodecane, J. Fluid Mech. 382 (1999) 63-86]. Using this particular kinetic relation, Rankine-Hugoniot relations are closed at such fronts. Then it is possible to solve the associated reactive Riemann problem. However, another difficulty is present to solve the multi-dimensional propagation of permeable fronts. This kind of front is subsonic and a conventional averaging scheme (such as Godunov scheme) is inappropriate. To overcome this difficulty, the reactive Riemann problem solution is embedded into the discrete equations method (DEM) [R., Abgrall, R., Saurel, Discrete equations for physical and numerical compressible multiphase mixtures, J. Comp. Phys. 186 (2003) 361-396; R., Saurel, S., Gavrilyuk, F., Renaud, A multiphase model with internal degrees of freedom: application to Shock-Bubble Interaction, J. Fluid. Mech., 495 (2003) 283-321]. This numerical method necessitates deep extensions that are detailed herein. Numerical results are shown and validated over experimental data. Some examples show that the same method may be applied to the propagation of detonation fronts.

  2. Quantifying Evaporation in a Permeable Pavement System

    EPA Science Inventory

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  3. Alpha particles induce pan-nuclear phosphorylation of H2AX in primary human lymphocytes mediated through ATM.

    PubMed

    Horn, Simon; Brady, Darren; Prise, Kevin

    2015-10-01

    The use of high linear energy transfer radiations in the form of carbon ions in heavy ion beam lines or alpha particles in new radionuclide treatments has increased substantially over the past decade and will continue to do so due to the favourable dose distributions they can offer versus conventional therapies. Previously it has been shown that exposure to heavy ions induces pan-nuclear phosphorylation of several DNA repair proteins such as H2AX and ATM in vitro. Here we describe similar effects of alpha particles on ex vivo irradiated primary human peripheral blood lymphocytes. Following alpha particle irradiation pan-nuclear phosphorylation of H2AX and ATM, but not DNA-PK and 53BP1, was observed throughout the nucleus. Inhibition of ATM, but not DNA-PK, resulted in the loss of pan-nuclear phosphorylation of H2AX in alpha particle irradiated lymphocytes. Pan-nuclear gamma-H2AX signal was rapidly lost over 24h at a much greater rate than foci loss. Surprisingly, pan-nuclear gamma-H2AX intensity was not dependent on the number of alpha particle induced double strand breaks, rather the number of alpha particles which had traversed the cell nucleus. This distinct fluence dependent damage signature of particle radiation is important in both the fields of radioprotection and clinical oncology in determining radionuclide biological dosimetry and may be indicative of patient response to new radionuclide cancer therapies. PMID:26116906

  4. Characterising the distribution and morphology of creeks and pans on salt marshes in England and Wales using Google Earth

    NASA Astrophysics Data System (ADS)

    Goudie, Alice

    2013-09-01

    By using Google Earth images and simple morphometric analyses, pan and creek characteristics of salt marshes across England and Wales have been mapped and related to key environmental variables, including tidal range, sea level change, coastal configuration, sediment type and erosion state. Pan density was found to be higher on the west coast or where there is a moderate tidal range and low sea level change. Pan density is also higher on back barrier and drowned valley marshes and when creek density is low. Maximum pan size is partly controlled by pan density. Creek density and sinuosity showed great variability between areas with marshes in the south having a higher creek density. Creek density is related to tidal prism and marshes undergoing high rates of sea level change usually have higher creek densities. Marshes with an upstream configuration (embayment, drowned valley and back barrier) have lower creek densities due to a lower tidal prism. Sediment type also plays a role with lower creek densities found on coarser sediment types. Creek sinuosity seems to be largely controlled by tidal range with higher sinuosities on meso- or macro-tidal marshes. This large-scale, Google Earth-based, analysis of the distribution and likely environmental controls on salt marsh morphometry illustrates the utility of Digital Globes as sources of freely-available, high resolution imagery for geomorphological research.

  5. Thermal analysis of evaporative coolers

    NASA Astrophysics Data System (ADS)

    Ohuchi, Masatoshi; Furukawa, Masao; Oshima, Koichi

    1991-12-01

    In order to develop the conceptual design of the Thermal Control System (TCS) of HOPE (Japanese orbiting plane planned to be launched by H2 rocket), the thermal model of the evaporative cooling system of the U.S. Space Shuttle was analyzed. This consists of Flash Evaporator Subsystem (FES) at high altitude and Ammonia Boiler Subsystem (ABS) at low altitude, both of which are for cooling of the freon loops, and Water Spray Boiler Subsystem (WSB), for cooling of the oil loops. Simplified thermal models of these devices were constructed based in the reported data such as the geometries and the design requirements. The simulated results based on these thermal models were compared with the Shuttle postflight data. Integration of these subsystem models into the total TCS model is underway.

  6. The STM4195 Gene Product (PanS) Transports Coenzyme A Precursors in Salmonella enterica

    PubMed Central

    Ernst, Dustin C.

    2015-01-01

    ABSTRACT Coenzyme A (CoA) is a ubiquitous coenzyme involved in fundamental metabolic processes. CoA is synthesized from pantothenic acid by a pathway that is largely conserved among bacteria and eukaryotes and consists of five enzymatic steps. While higher organisms, including humans, must scavenge pantothenate from the environment, most bacteria and plants are capable of de novo pantothenate biosynthesis. In Salmonella enterica, precursors to pantothenate can be salvaged, but subsequent intermediates are not transported due to their phosphorylated state, and thus the pathway from pantothenate to CoA is considered essential. Genetic analyses identified the STM4195 gene product of Salmonella enterica serovar Typhimurium as a transporter of pantothenate precursors, ketopantoate and pantoate and, to a lesser extent, pantothenate. Further results indicated that STM4195 transports a product of CoA degradation that serves as a precursor to CoA and enters the biosynthetic pathway between PanC and CoaBC (dfp). The relevant CoA derivative is distinguishable from pantothenate, pantetheine, and pantethine and has spectral properties indicating the adenine moiety of CoA is intact. Taken together, the results presented here provide evidence of a transport mechanism for the uptake of ketopantoate, pantoate, and pantothenate and demonstrate a role for STM4195 in the salvage of a CoA derivative of unknown structure. The STM4195 gene is renamed panS to reflect participation in pantothenate salvage that was uncovered herein. IMPORTANCE This manuscript describes a transporter for two pantothenate precursors in addition to the existence and transport of a salvageable coenzyme A (CoA) derivative. Specifically, these studies defined a function for an STM protein in S. enterica that was distinct from the annotated role and led to its designation as PanS (pantothenate salvage). The presence of a salvageable CoA derivative and a transporter for it suggests the possibility that this compound is present in the environment and may serve a role in CoA synthesis for some organisms. As such, this work raises important question about CoA salvage that can be pursued with future studies in bacteria and other organisms. PMID:25645561

  7. Probing light dark matter via evaporation from the Sun

    NASA Astrophysics Data System (ADS)

    Kouvaris, Chris

    2015-10-01

    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 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.

  8. 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.

  9. Peroxyacetylnitrate (PAN) in the atmosphere of Edmonton, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Peake, Eric; MacLean, M. A.; Lester, P. F.; Sandhu, H. S.

    Peroxyacetyl nitrate (PAN) concentrations were measured from December 1982 to May 1984 in downtown Edmonton, Alberta, as well as upwind and downwind of the city. The highest PAN concentration recorded in Edmonton was 7.5 ppb, and the mean daily maximum was 0.6 ppb. Maximum PAN and ozone concentrations were often reached in the early afternoon but there were many exceptions, with maxima as early as 0900 MST and as late as 2000 MST. PAN often persisted throughout the night in Edmonton, whereas in Calgary it disappeared rapidly in the evening. Edmonton PAN concentrations showed seasonal variation and were limited in the wintertime by the lack of solar radiation and in the summer by the low concentration of pollutants. PAN episodes were highly correlated with the presence of anticyclonic synoptic disturbances (ridges) in the upper air flow. Surface synoptic conditions varied but weak pressure gradients were common to all episodes. Seasonal and diurnal variations of PAN are discussed in relation to observations from Calgary, Alberta; Los Angeles, CA; and other North American cities.

  10. 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 705848 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

  11. Summertime PAN on boundary layer over the Northern Pacific Ocean

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  12. Evaporation by mechanical vapor recompression

    NASA Astrophysics Data System (ADS)

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

    1980-04-01

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

  13. Evaluating The Reliability of Point Estimates of Wetland Evaporation

    NASA Astrophysics Data System (ADS)

    Gavin, H.; Agnew, C. T.

    The Penman-Monteith formulation of evaporation has been criticised for its reliance upon point estimates raising concerns that areal estimates of wetland evaporation based upon single weather stations can be misleading. Typically wetlands are composed of a complex mosaic of land cover types each of which can produce different evaporative rates. The need to account for wetland patches when monitoring hydrological fluxes has been noted, while Morton (1983) has long argued for a fundamentally different approach to the calculation of regional evaporation. This paper presents the work carried out at wet grassland in Southern England that was monitored with several automatic weather stations (AWS) and a bowen ratio station to investigate microclimate variations. The significance of fetch was examined using the approach adopted by Gash (1986) based upon surface roughness to estimate the fraction of evaporation sensed from a specific distance upwind of the monitoring station. This theoretical analysis reveals that the fraction of evaporation contributed by the surrounding area steadily increases to a value of 77% at a distance of 224m and thereafter declines rapidly, under stable atmospheric conditions. Thus point climate observations may not reflect surface conditions at greater distances. This result was tested through the deployment offour AWS around the wetland. The data yielded a different response, suggesting that homogeneous conditions prevailed and the central AWS did provide reliable areal estimates of evaporation. The apparent contradiction is a result of not accounting for wind speeds found in wetlands that lead to widespread atmospheric mixing. These findings are typical of moist conditions whereas for example Guo and Scheupp (1994) found that a patchwork of dry fields and wet ditches, characteristic of the study site in summer, could produce differences of up to 50% in evaporation. The paper will also present the initial results of an investigation of the role of dry patches upon wetland evaporation estimates. Morton, F.I. 1983 Operational estimates of evapotranspiration and their significance to the science and practice of hydrology. Journal of Hydrology 66 1:76. Gash, J.H.C. 1986 A note on estimating the effect of limited fetch on micrometeorological evaporation measurements. Boundary Layer Meteorology 35: 409-413. Guo, Y. Schuepp, P.H. 1994a On surface energy balance over the northern wetlands 1. The effects of small-scale temperature and wetness heterogeneity. Journal of Geophysical Research 99 (D1) 1601-1612.

  14. SEWAGE DISPOSAL BY EVAPORATION-TRANSPIRATION

    EPA Science Inventory

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

  15. Iodine retention during evaporative volume reduction

    DOEpatents

    Godbee, H.W.; Cathers, G.I.; Blanco, R.E.

    1975-11-18

    An improved method for retaining radioactive iodine in aqueous waste solutions during volume reduction is disclosed. The method applies to evaporative volume reduction processes whereby the decontaminated (evaporated) water can be returned safely to the environment. The method generally comprises isotopically diluting the waste solution with a nonradioactive iodide and maintaining the solution at a high pH during evaporation.

  16. 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.

  17. An Analytical Solution for Raindrop Evaporation and Its Application to Radar Rainfall Measurements.

    NASA Astrophysics Data System (ADS)

    Li, Xiaowen; Srivastava, Ramesh C.

    2001-09-01

    An analytical solution for the evaporation of a single raindrop is derived in this paper. Based on this solution, a parameter D( is defined as the diameter of the raindrop that just evaporates completely after falling through a certain distance in a prescribed environment. The parameter D( is then used for studying the modification of raindrop size distribution by evaporation in a steady, still atmosphere. The results for the Marshall-Palmer distribution are used to discuss errors caused by rain evaporation in radar rainfall measurements. Quantitative estimation of these errors, or as an equivalent, estimation of the rain evaporation along the falling path, using both radar reflectivity Z and radar differential reflectivity ZDR techniques, is studied. The results show that, for the detection of rain evaporation, reflectivity is more sensitive than differential reflectivity, whereas for the estimation of rainfall rate R, an empirical ZDR-Z-R formula is more robust and accurate than a Z-R formula.

  18. Role of entrapped vapor bubbles during microdroplet evaporation

    NASA Astrophysics Data System (ADS)

    Putnam, Shawn A.; Byrd, Larry W.; Briones, Alejandro M.; Hanchak, Michael S.; Ervin, Jamie S.; Jones, John G.

    2012-08-01

    On superheated surfaces, the air bubble trapped during impingement grows into a larger vapor bubble and oscillates at the frequency predicted for thermally induced capillary waves. In some cases, the entrapped vapor bubble penetrates the droplet interface, leaving a micron-sized coffee-ring pattern of pure fluid. Vapor bubble entrapment, however, does not influence the evaporation rate. This is also true on laser heated surfaces, where a laser can thermally excite capillary waves and induce bubble oscillations over a broad range of frequencies, suggesting that exciting perturbations in a pinned droplets interface is not an effective avenue for enhancing evaporative heat transfer.

  19. Aerogel Materials by Evaporative Drying: Potential for Space Applications

    NASA Technical Reports Server (NTRS)

    Plawsky, Joel L.

    1999-01-01

    Aerogel wafers were made using an evaporative drying procedure. The main steps were sol formulation, gelation, aging, capping, and drying. Of these, the most critical step was drying. Both the rate of evaporation and temperature of the system must be controlled for best results. Aerogel materials should be benchmarked against more traditional foams and current systems may have to be redesigned to make best use of aerogel strengths. Finally, the flexibility of this procedure lends itself to producing aerogel materials for many uses other than insulation. Such uses may include catalysis, sensing, and composite materials.

  20. Dynamics of Soil Water Evaporation during Soil Drying: Laboratory Experiment and Numerical Analysis

    PubMed Central

    Han, Jiangbo; Zhou, Zhifang

    2013-01-01

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

  1. 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

  2. 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.

  3. 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.

  4. Influence of random point defects introduced by proton irradiation on the flux creep rates and magnetic field dependence of the critical current density J c of co-evaporated GdBa2Cu3O7‑δ coated conductors

    NASA Astrophysics Data System (ADS)

    Haberkorn, N.; Kim, Jeehoon; Suárez, S.; Lee, Jae-Hun; Moon, S. H.

    2015-12-01

    We report the influence of random point defects introduced by 3 MeV proton irradiation (doses of 0.5 × 1016, 1 × 1016, 2 × 1016 and 6 × 1016 cm‑2) on the vortex dynamics of co-evaporated 1.3 μm thick, GdBa2Cu3O7‑δ coated conductors. Our results indicate that the inclusion of additional random point defects reduces the low field and enhances the in-field critical current densities J c. The main in-field J c enhancement takes place below 40 K, which is in agreement with the expectations for pinning by random point defects. In addition, our data show a slight though clear increase in flux creep rates as a function of irradiation fluence. Maley analysis indicates that this increment can be associated with a reduction in the exponent μ characterizing the glassy behavior.

  5. Negative pressure characteristics of an evaporating meniscus at nanoscale.

    PubMed

    Maroo, Shalabh C; Chung, Jn

    2011-01-01

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

  6. Effect of purge air humidity on automotive evaporative control performance

    SciTech Connect

    Gabele, P.A.; Perry, N. )

    1988-01-01

    Evaporative emissions from automobiles account for approximately 16 percent of the nationwide anthropogenic nonmethane organic compound emissions. These emissions participate in atmospheric photochemical processes that produce ozone and other oxidant compounds. Because federal ozone standards are currently being violated in over 70 areas within the United States, control of organic compound emissions including evaporative emissions from automobiles has been given a high priority by the EPA. Test results in EPA's emission factor surveillance program indicate that average evaporative emissions rates from in-use vehicles are roughly six-times higher than the 2 grams/test standard level. Much of this exceedance can be attributed to the high reid vapor pressure (RVP) of the fuels being used in the surveyed vehicles which averaged 11.5 psi RVP as compared to 9.0 psi RVP for the EPA certification fuel. However, even when tested on 9.0 psi RVP fuel, a large number of problem- free vehicles still exceeded the standard. Fuel volatility considerations aside, evaporative control systems fail to provide the level of control in real-life that is demonstrated in the certification (i.e., the federal test procedure) environment. Accordingly, conditions or factors thought to influence in-use performance on evaporative control devices are now under investigation.

  7. Numerical Study of a Hydrodynamic Instability Driven by Evaporation

    NASA Astrophysics Data System (ADS)

    Hernandez-Zapata, Sergio; Romo-Cruz, Julio Cesar Ruben; Lopez-Sanchez, Erick Javier; Ruiz-Chavarria, Gerardo

    2013-11-01

    The study of hydrodynamic instabilities in liquid layers produced by evaporation has several applications on industry and technology. In this work we study numerically the conditions under which a liquid layer becomes unstable when evaporation in the vapor-liquid interphase is present. The evaporation process follows the Hertz-Knudsen law (the evaporation rate is proportional to the difference between the saturated vapor pressure at the liquid layer temperature and the vapor partial pressure in the environment). Additionally to the usual boundary conditions on solid walls (for example, the non-slip condition for the velocity), we analyze the boundary conditions in the vapor-liquid interphase where the momentum and energy balances have to be taken into account and where the evaporation plays a crucial role. To solve this problem the linear theory of stability is used; that is, a small perturbation around the basic solution is applied (flow at rest and a temperature stationary field). The equations are solved using the Chebyshev pseudo-spectral method. The results are compared with the more usual Rayleigh-Bnard and Marangoni mechanisms as well as with some experiments carried out by our team. Authors acknowledge DGAPA-UNAM by support under project IN116312, ``Vorticidad y Ondas no lineales en fluidos.''

  8. Influence of electron evaporative cooling on ultracold plasma expansion

    SciTech Connect

    Wilson, Truman; Chen, Wei-Ting; Roberts, Jacob

    2013-07-15

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

  9. Membrane-Based Water Evaporator for a Space Suit

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  10. 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 E9701', N4513' , altitude 1520m, annual average precipitation 61.8mm and annual evaporation 2600mm (pan 20cm). The experiment field contains 45 lysimeters (65cm diameter). 11 different water table depths are set in the lysimeters, which are 0.5m, 0.75m, 1.0m, 1.25m, 1.5m, 2.0m, 2.5m, 3.0m, 4.0m, 5.0m and 6.0m. The water table in the lysimeter is controlled by Marriott Bottle System. The evaporation and percolation is measured for three different soil types (silt sandy soil, loam soil and clay soil) in the 11 different water table depths. Based on the data from 2006 to 2010, the influences of atmosphere evaporation capacity, phreatic water depth and soil textures are analyzed. Empirical formulae for estimating phreatic evaporation are regressed. The fitting precision of the different formulae are evaluated. The results show that, fitting effect of common empirical formulae is good in Shule river basin. For the different soil types, fitting effect of silt soil is the best, while that of clay soil is relatively low. At last, formulae fitted in other areas and phreatic evaporation tests are summarized. The reasons of difference of fitted coefficients lie in three aspects: the range of depth of groundwater, choice of the value of water evaporation, method to optimize coefficients. Physical meaning of the coefficients in empirical formulae is analyzed. The features, fitting effect and notes in application of formulae are evaluated. The results are applied in water requirement calculation of ecological conservation Dunhuang Xihu Nature Reserve. Water sources, plant transpiration, and phreatic evaporation are simulated by the groundwater numerical model and the total ET of nature reserve is calculated. The supplementary water requirement is advanced. Key words: phreatic evaporation; empirical formulae; fitting precision; Shule river basin

  11. Pressure and purging effects on material outgassing and evaporation

    NASA Astrophysics Data System (ADS)

    Scialdone, John J.

    2003-09-01

    Full material outgassing and evaporation rates do not occur unless carried out under high vacuum. The evaporation and the outgassing rates are reduced by orders of magnitude when carried at pressures higher than about 10E-2 torr. This paper reports some experimental data on the outgassing, evaporation, and distillations rates carried at various vacuum pressures and reported in the literature. The data in conjunction with the equation for mass transport have been employed to evaluate the outgassing rates and the corresponding flow conductances for materials exposed to different residual air pressures. The conductances are controlled by the outgassing gases diffusing through the external pressure and through a film thickness on the outgassing surface. The evaporation of water, M=18 g/mole at 293 K with a saturated vapor pressure of 17 torr, has been considered. Also, the outgassing of materials with an average molecular mass of 100 g/mole and equivalent vapor pressures of 1E-8 torr have been considered. The 1E-8 vapor pressure corresponds to a combined outgassing rate of 1E-9 g/cm2/s obtained at the end of a full vacuum outgassing test of a group of materials. The results are employed to estimate the rates of evaporation and outgassing of materials under various conditions of external pressures knowing the rates obtainable in full vacuum. It has been calculated among others that the evaporation of water at a normal temperature and under normal air pressure is 9.6E-6 g/cm2/s. The outgassing for the M=100 g/mole materials with an outgassing rate of 1E-9 g/cm2/s in full vacuum is 5E-13 g/cm2/s under normal external pressure. These are about 5 orders and 4 orders of magnitude respectively lower than the rates in full vacuum. Their conductance's at normal pressure have been calculated to be 1.06 cm3/cm2/s for water and 8.51 for the M=100 g/mole. The corresponding film thicknesses on the outgassing surfaces are about 0.22 cm and 0.012 cm respectively. The effect of clean gaseous purging on the outgassing has also been considered.

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

    SciTech Connect

    Sebesta, F.; John, J.; Motl, A.

    1996-05-01

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

  13. 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...

  14. Deep-sky photography - TMax or Technical Pan?

    NASA Astrophysics Data System (ADS)

    Martys, C. R.

    1991-08-01

    Baked Technical Pan 2415 film was compared with the new T-grain emulsions TMax 100, TMax 400 and TMax 3200 (untreated) in order to evaluate the effectiveness of the new materials for long exposure deep-sky photography.

  15. Improvements in analysis of atmospheric peroxyacetyl nitrate (PAN)

    NASA Astrophysics Data System (ADS)

    Helmig, Detlev; Müller, Josef; Klein, Werner

    Common analytical techniques for PAN determination were modified in order to obtain a sensitive and automatic analysis system. PAN was synthesized by nitration of peracetic acid in hexane, The PAN/hexane solution was purified by water extraction. The quantification was performed determining acetate or nitrite by ion chromatography following alkaline hydrolysis. The validity was checked by liquid i.r. speetroscopy. NMR studies revealed a singulet signal at 2.27 ppm. The precision and sensitivity of the gas Chromatographic analyses were improved by the use of wide bore capillary columns coated with Carbowax 400. The developed system enables automatic and continuous PAN measurements at a 10 min sampling sequence and with a detection limit of 50 ppt.

  16. Pan trapping soybean aphids (Hemiptera: Aphididae) using attractants.

    PubMed

    Behrens, Nicholas S; Zhu, Junwei; Coats, Joel R

    2012-06-01

    Since its introduction into the United States in the past 10 yr, soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has been a damaging pest to soybean, Glycine max (L.) Merrill. During 2008 and 2009, fields in central and north central Iowa experienced pockets of high soybean aphid populations. Electroantennograms have shown that soybean aphid alatae are capable of detecting host plant volatiles and sex pheromones. Here, we evaluated baited pan traps as a potential soybean aphid attractant. Yellow pan traps were placed in soybean fields after planting along with lures that contained plant volatiles and sex pheromones in 2008 or sex pheromones only in 2009. Pan trap contents were collected weekly, and plant counts also were conducted. Aphids were identified, and soybean aphids were counted to determine whether one chemical lure was more attractive to spring migrants than other lures. In both years, soybean aphids collected in pan traps with lures were not significantly different from the other products tested. PMID:22812127

  17. PAN and the NOx budget of the troposphere. [Peroxyacylnitrates

    NASA Technical Reports Server (NTRS)

    Brewer, D. A.; Augustsson, T. R.; Levine, J. S.

    1982-01-01

    The present investigation has the objective to examine the interaction of NOx with the nonmethane hydrocarbons (NMHCs) photochemistry. Attention is given to the influence of temperature, transport, and hydrocarbon radical reactions on the profiles of peroxyacylnitrates (PANs) and NO2. A lumped NMHC chemical reaction scheme was used in a one-dimensional photochemical model of the global troposphere. Model calculations were performed with various temperature profiles and the corresponding solar zenith angles to examine seasonal variations in the profiles of PAN and NOx. A study of the effects of changing temperature and solar zenith angle on the profiles of PAN and NOx showed that the amount of NO2 tied up in PAN increased as temperature decreased.

  18. 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.

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

    SciTech Connect

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

    1982-01-01

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

  20. PAN's labyrinth: a multidisciplinary delayed diagnosis and patient's perspective.

    PubMed

    Barlow, Emma Louise; Seddon, Owen; Healy, Brendan

    2016-01-01

    Polyarteritis nodosa (PAN) is a rare, severe form of vasculitis affecting medium-sized vessels. It manifests as a multisystem syndrome, and may be associated with hepatitis B virus-associated PAN (HBV-PAN) although the incidence of this is declining with better vaccination strategies and awareness of bloodborne virus screening. We report a case in which a patient displayed many classical features of the disease, occurring separately over a period of months and leading to contact with various medical specialties. Managing each symptom in isolation led to a number of misdiagnoses (including testicular cancer) and the patient experienced considerable psychological stress and morbidity as a result. The case was complicated by acute pancreatitis developing after an initial treatment response. This may have been iatrogenic (as a consequence of either entecavir or steroids) or secondary to PAN. For our patient, this led to a protracted clinical course but eventual complete resolution of both pathologies. PMID:26733433

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  3. Pan-STARRS-1 Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Huber, Mark; PS1-IPP Team, PS1 Science Consortium

    2015-01-01

    The Panoramic Survey Telescope And Rapid Response System-1 (Pan-STARRS-1, PS1) has been in full operation since Spring 2010 and concluded the PS1 Science Consortium (PS1SC) observational program in early 2014. The Medium Deep Survey (MDS) component of the program, allocated 25% of the time, regularly visited 10 fields (~7 sq. deg. each) with significant multi-wavelength overlap from previous and concurrent surveys (e.g. SDSS, DEEP2, CDFS, COSMOS, GALEX). The cadence generally includes the g,r,i,z filters for a MDS field every 3 days with a nightly stack depth of r,i~23.5 mag and the y filter primarily during bright time over the 6-8 month season the field is visible. While regularly producing data for the transient event discovery and science consortium programs, development work continued to improve the single exposures though production of deep stacks for reprocessing into the final and public release. The data products, to be publicly available after the post-observing proprietary period, will be summarized.For details on PS1 and the Science Collaboration, visit http://ps1sc.org/

  4. Pan-STARRS-1 Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Huber, Mark

    2015-08-01

    The Panoramic Survey Telescope And Rapid Response System-1 (Pan-STARRS-1, PS1) has been in full science operation since Spring 2010 and concluded the observing program for the PS1 Science Consortium (PS1SC) in early 2014. The Medium Deep Survey (MDS) component of the program regularly visited 10 fields (~7 sq. deg. each) with significant multi-wavelength overlap from previous and concurrent surveys (e.g. SDSS, DEEP2, CDFS, COSMOS, GALEX) for 25% of the total time allocation. The cadence generally includes the g,r,i,z filters for a MDS field every 3 days over the 6-8 month season the field is visible, with the y filter done primarily during bright time. The nightly stacks of eight exposures typically reach depths of r,i~23.5 mag. Development work continued to improve the single exposure processing though to deep stacks during the transient event discovery and other science consortium programs over the course of the survey, the culmination of those improvements being applied in a more uniformly reprocessed dataset used for the public data release. A summary of the MDS public data release products will be presented.For details on PS1 and the Science Collaboration, visit http://ps1sc.org/

  5. A pan-African Flood Forecasting System

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  6. Indirect evaporative coolers with enhanced heat transfer

    SciTech Connect

    Kozubal, Eric; Woods, Jason; Judkoff, Ron

    2015-09-22

    A separator plate assembly for use in an indirect evaporative cooler (IEC) with an air-to-air heat exchanger. The assembly includes a separator plate with a first surface defining a dry channel and a second surface defining a wet channel. The assembly includes heat transfer enhancements provided on the first surface for increasing heat transfer rates. The heat transfer enhancements may include slit fins with bodies extending outward from the first surface of separator plate or may take other forms including vortex generators, offset strip fins, and wavy fins. In slit fin implementations, the separator plate has holes proximate to each of the slit fins, and the separator plate assembly may include a sealing layer applied to the second surface of the separator plate to block air flow through the holes. The sealing layer can be a thickness of adhesive, and a layer of wicking material is applied to the adhesive.

  7. Evaporative oxidation treatability test report

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    Matsuda, Akira; Ide, Tetsuo; Yukino, Keiji

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

  9. Enhancement of Water Evaporation on Solid Surfaces with Nanoscale Hydrophobic-Hydrophilic Patterns

    NASA Astrophysics Data System (ADS)

    Wan, Rongzheng; Wang, Chunlei; Lei, Xiaoling; Zhou, Guoquan; Fang, Haiping

    2015-11-01

    Using molecular dynamics simulations, we show that the evaporation of nanoscale water on hydrophobic-hydrophilic patterned surfaces is unexpectedly faster than that on any surfaces with uniform wettability. The key to this phenomenon is that, on the patterned surface, the evaporation rate from the hydrophilic region only slightly decreases due to the correspondingly increased water thickness; meanwhile, a considerable number of water molecules evaporate from the hydrophobic region despite the lack of water film. Most of the evaporated water from the hydrophobic region originates from the hydrophilic region by diffusing across the contact lines. Further analysis shows that the evaporation rate from the hydrophobic region is approximately proportional to the total length of the contact lines.

  10. 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.

  11. Measurement and analysis of evaporation from an inactive outdoor swimming pool

    SciTech Connect

    Smith, C.C.; Loef, G. ); Jones, R. )

    1994-07-01

    Evaporation rates and total energy loads from an unoccupied, heated, outdoor pool in Fort Collins, Colorado were investigated. Pool and air temperatures, humidity, thermal radiation, wind speed, and water loss due to evaporation were measured over 21 test periods ranging from 1.1 to 16.2 hours during August and September, 1992. Data were analyzed and compared to commonly used evaporation rate equations, most notably that used in the ASHRAE Applications Handbook. Measured evaporation was 72% of the ASHRAE calculated value with near-zero wind velocity, and 82% of the ASHRAE value at 2.2 m/s wind velocity. A modified version of the ASHRAE equation was developed. Two overnight tests showed energy loss of 56% by evaporation, 26% by radiation, and 18% by convection. A correlation between radiation loss and temperatures was also found for the range of test conditions.

  12. Area-to-point regression kriging for pan-sharpening

    NASA Astrophysics Data System (ADS)

    Wang, Qunming; Shi, Wenzhong; Atkinson, Peter M.

    2016-04-01

    Pan-sharpening is a technique to combine the fine spatial resolution panchromatic (PAN) band with the coarse spatial resolution multispectral bands of the same satellite to create a fine spatial resolution multispectral image. In this paper, area-to-point regression kriging (ATPRK) is proposed for pan-sharpening. ATPRK considers the PAN band as the covariate. Moreover, ATPRK is extended with a local approach, called adaptive ATPRK (AATPRK), which fits a regression model using a local, non-stationary scheme such that the regression coefficients change across the image. The two geostatistical approaches, ATPRK and AATPRK, were compared to the 13 state-of-the-art pan-sharpening approaches summarized in Vivone et al. (2015) in experiments on three separate datasets. ATPRK and AATPRK produced more accurate pan-sharpened images than the 13 benchmark algorithms in all three experiments. Unlike the benchmark algorithms, the two geostatistical solutions precisely preserved the spectral properties of the original coarse data. Furthermore, ATPRK can be enhanced by a local scheme in AATRPK, in cases where the residuals from a global regression model are such that their spatial character varies locally.

  13. Migration of ATLAS PanDA to CERN

    NASA Astrophysics Data System (ADS)

    Stewart, Graeme Andrew; Klimentov, Alexei; Koblitz, Birger; Lamanna, Massimo; Maeno, Tadashi; Nevski, Pavel; Nowak, Marcin; Emanuel De Castro Faria Salgado, Pedro; Wenaus, Torre

    2010-04-01

    The ATLAS Production and Distributed Analysis System (PanDA) is a key component of the ATLAS distributed computing infrastructure. All ATLAS production jobs, and a substantial amount of user and group analysis jobs, pass through the PanDA system, which manages their execution on the grid. PanDA also plays a key role in production task definition and the data set replication request system. PanDA has recently been migrated from Brookhaven National Laboratory (BNL) to the European Organization for Nuclear Research (CERN), a process we describe here. We discuss how the new infrastructure for PanDA, which relies heavily on services provided by CERN IT, was introduced in order to make the service as reliable as possible and to allow it to be scaled to ATLAS's increasing need for distributed computing. The migration involved changing the backend database for PanDA from MySQL to Oracle, which impacted upon the database schemas. The process by which the client code was optimised for the new database backend is discussed. We describe the procedure by which the new database infrastructure was tested and commissioned for production use. Operations during the migration had to be planned carefully to minimise disruption to ongoing ATLAS offline computing. All parts of the migration were fully tested before commissioning the new infrastructure and the gradual migration of computing resources to the new system allowed any problems of scaling to be addressed.

  14. An allometric study of the frontal sinus in Gorilla, Pan and Pongo.

    PubMed

    Blaney, S P

    1986-01-01

    There is considerable speculation about the role and significance of the paranasal sinuses in the Hominoidea, and this study aims to present new data about an old problem from cephalograms of dried crania. Measurements of frontal sinus volumes were determined for Gorilla gorilla gorilla; G. gorilla beringei and Pan troglodytes. By adopting an allometric approach it was determined that the frontal sinus volume of Gorilla is relatively smaller than that of Pan, and that the frontal sinus of G. g. gorilla is relatively smaller than that of G. g. beringei. Frontal sinus volume scales in a positive allometric fashion relative to skull length. Since the slope is steeper for Pan, frontal sinus volume is increasing at a faster rate than in Gorilla. Sexual dimorphism in frontal sinus volume is present. Thirty crania of Pongo were investigated for evidence of pneumatization of the frontal bone. In no case was secondary invasion of the frontal bone by the maxillary antrum observed. In Gorilla, the nasal cavity volume scales isometrically with skull length. The scaling relationships discussed do not support any 'functional' role of the frontal sinus associated with nasal function but suggest a 'structural' role associated with craniofacial architecture. PMID:3583154

  15. 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

  16. Volatile Composition of Comet C/2012 K1 (PanSTARRS)

    NASA Astrophysics Data System (ADS)

    Roth, Nathan; Gibb, Erika; Bonev, Boncho P.; DiSanti, Michael A.; Villanueva, Geronimo L.; Paganini, Lucas; Mumma, Michael J.

    2015-11-01

    On 2014 May 22 and 24 we characterized the volatile composition of the dynamically new Oort Cloud comet C/2012 K1 (PanSTARRS) using the long-slit, high resolution (λ/Δλ ≈ 25,000) infared echelle spectrograph (NIRSPEC) at the 10m Keck 2 telescope on Maunakea, HI. We detected fluorescent emission from six primary species (H2O, HCN, CH4, C2H6, CH3OH, and CO) and prompt emission from one product species (OH* - a directory proxy for H­2O). Upper limits were derived for C2H2 and H2CO. We report rotational temperatures, production rates, and mixing ratios (relative to water). Based on the inventory of comets characterized to date, mixing ratios of trace gases in C/2012 K1 (PanSTARRS) are about normal - CH3OH and C2H6 are slightly enriched, CO, CH4, HCN, and H2CO are average, and C­2H2 is depleted. I will discuss C/2012 K1 (PanSTARRS) in the context of an emerging taxonomy for comets based on volatile composition.This work is supported through the NASA Missouri Space Grant Consortium and the National Science Foundation (NSF 1211362), the NASA Astrobiology Institute through a grant to the Goddard Center for Astrobiology (811073.02.12.03.91), and the NASA Planetary Astronomy Program (811073.02.03.03.43).

  17. Evaporation and diurnal base flows for ephemeral stream in the Soudano-sahelian zone, Burkina Faso

    NASA Astrophysics Data System (ADS)

    Mande, T.; Ceperley, N. C.; Weijs, S. V.; Parlange, M. B.

    2012-12-01

    The base flow generation in Soudano-sahelian zone is controlled by the spatial and temporal variability of groundwater storage and evaporation. The high daytime evaporation rate in this zone leads to a corresponding decrease in the stream flow generation. Other investigations have investigated the influence of evaporation on base flow generation, though rarely the evaporation has been independently measured. We use actual evaporation data measured with an eddy covariance station to assess the impact on the groundwater storage pattern and streamflow. Data to address these issues were collected during 2010 rainy season in the Tambarga basin (area = 3.5 km2) in Southeast Burkina Faso. Based on the simple relationship observed between the diurnal cycles of outflow and evapotranspiration a control area draining to the stream could be defined. This area is the ratio between the ''lost'' water in hourly streamflow and the actual evaporation flux. This area changes following rain events but remains stable during dry days, when the riparian zone appears to be the primary source of evaporation. Additionally, a clockwise hysteresis relationship was observed between evaporation and groundwater outflow. This relationship allows us to identify the daily partitioning of evapotranspiration output over the basin. The importance of evaporation into the atmosphere for controlling the diurnal pattern of streamflow is discussed in detail in this presentation.

  18. 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.

  19. 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.

  20. Testing of the Multi-Fluid Evaporator Engineering Development Unit

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  1. A microfluidic device based on an evaporation-driven micropump.

    PubMed

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

    2015-04-01

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

  2. Numerical Modeling of Water Flow and Salt Transport in Bare Saline Soil Subjected to Transient Evaporation

    NASA Astrophysics Data System (ADS)

    Geng, X.; Boufadel, M.; Saleh, F. S.

    2014-12-01

    It has been found that evaporation over bare soil plays an important role in subsurface solute transport processes. 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 transient evaporation. The bulk aerodynamic formulation was adopted to simulate transient evaporation rate at ground surface. Subsurface flow pattern, moisture distribution, and salt migration were quantified. Key factors likely affecting this process, including saturated hydraulic conductivity, capillary drive, air humidity, and surrounding water supply, were examined. The results showed that evaporation induced an upward flow pattern, which led to a high saline plume formed beneath the evaporation zone. In absence of surrounding water supply, as the humidity between the ground surface and air tended to equilibrium, evaporation-induced density gradient generated pore water circulations around the plume edge and caused the salt to migrate downwards with "finger" shapes. It was found that capillary properties and atmospheric condition had significant impacts on subsurface moisture distribution and salt migration in response to the evaporation. Larger capillary fringe and/or lower air humidity would allow evaporation to extract more water from the ground. It would induce a larger and denser saline plume formed beneath the evaporation zone. The results also suggested that the presence of the surrounding water supply (represented as a constant water table herein) could provide a steady evaporation rate at the ground surface; meanwhile, in response to the evaporation, a hydraulic gradient was formed from the water supply boundary, which induced an inclined upper saline plume with greater density far from the supply boundary.

  3. PEP725 Pan European Phenological Database

    NASA Astrophysics Data System (ADS)

    Koch, Elisabeth; Adler, Silke; Ungersbck, 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 Linn 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.

  4. PEP725 Pan European Phenological Database

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

    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 Linn 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". 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 network operators to get access to the data before one can start to bring them in a uniform style. From 2004 to 2009 the COST-action 725 established a European wide data set of phenological observations. But the deliverables of this COST action was not only the common phenological database and common observation guidelines - COST725 helped to trigger a revival of some old networks and to establish new ones as for instance in Sweden. At the end of 2009 the COST action the database comprised about 8 million data in total from 15 European countries plus the data from the International Phenological Gardens IPG. In January 2010 PEP725 began its work as follow up project with funding from EUMETNET the network of European meteorological services and of ZAMG the Austrian national meteorological service. PEP725 not only will take over the part of maintaining, updating the COST725 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.

  5. PEP725 Pan European Phenological Database

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  6. Rationale and design of the Pan-African Sudden Cardiac Death survey: the Pan-African SCD study

    PubMed Central

    Bonny, Aimé; Bonny, Aimé; Ngantcha, Marcus; Ndongo Amougou, Sylvie; Kane, Adama; Marrakchi, Sonia; Okello, Emmy; Taty, Georges; Gehani, Abdulrrazzak; Diakite, Mamadou; Talle, Mohammed A; Lambiase, Pier D; Houenassi, Martin; Chin, Ashley; Otieno, Harun; Temu, Gloria; Koffi Owusu, Isaac; Karaye, Kamilu M; Awad, Abdalla AM; Gregers Winkel, Bo; Priori, Silvia G; Priori, Silvia G

    2014-01-01

    Summary Background The estimated rate of sudden cardiac death (SCD) in Western countries ranges from 300 000 to 400 000 annually, which represents 0.36 to 1.28 per 1 000 inhabitants in Europe and the United States. The burden of SCD in Africa is unknown. Our aim is to assess the epidemiology of SCD in Africa. Methods The Pan-Africa SCD study is a prospective, multicentre, community-based registry monitoring all cases of cardiac arrest occurring in victims over 15 years old. We will use the definition of SCD as ‘witnessed natural death occurring within one hour of the onset of symptoms’ or ‘unwitnessed natural death within 24 hours of the onset of symptoms’. After appro val from institutional boards, we will record demographic, clinical, electrocardiographic and biological variables of SCD victims (including survivors of cardiac arrest) in several African cities. All deaths occurring in residents of districts of interest will be checked for past medical history, circumstances of death, and autopsy report (if possible). We will also analyse the employment of resuscitation attempts during the time frame of sudden cardiac arrest (SCA) in various patient populations throughout African countries. Conclusion This study will provide comprehensive, contemporary data on the epidemiology of SCD in Africa and will help in the development of strategies to prevent and manage cardiac arrest in this region of the world. PMID:25192301

  7. Formation, levitation and evaporation of unsupported liquid fuel droplet clusters

    NASA Astrophysics Data System (ADS)

    Liu, Song

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

  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. Out-of-tank evaporator demonstration. Final report

    SciTech Connect

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

    1998-02-01

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

  10. 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 ~8C reduction over ambient temperatures and never exceeded 30C. 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

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

    USGS Publications Warehouse

    Moreo, Michael T.; Swancar, Amy

    2013-01-01

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

  12. Observations on an evaporative, elbow thermosyphon

    SciTech Connect

    Lock, G.S.H.; Fu, J. )

    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.

  13. Simple, low cost, and highly stable Pd evaporation source for use in UHV

    SciTech Connect

    De Cooman, B.C.; Vook, R.W.

    1982-09-01

    The design of a source for the thermal evaporation of Pd from a resistively heated W filament in UHV is presented. The source's main advantages are its simplicity, low cost, long lifetime, and stability at low deposition rates.

  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. 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.

  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. Qubit models of black hole evaporation

    NASA Astrophysics Data System (ADS)

    Avery, Steven G.

    2013-01-01

    Recently, several simple quantum mechanical toy models of black hole evaporation have appeared in the literature attempting to illuminate the black hole information paradox. We present a general class of models that is large enough to describe both unitary and nonunitary evaporation, and study a few specific examples to clarify some potential confusions regarding recent results. We also generalize Mathur's bound on small corrections to black hole dynamics. Conclusions are then drawn about the requirements for unitary evaporation of black holes in this class of models. We present a one-parameter family of models that continuously deforms nonunitary Hawking evaporation into a unitary process. The required deformation is large.

  18. Evaporative air conditioning in a manufacturing facility

    SciTech Connect

    Brown, C.D.; Leach, J.W.; Terry, S.D.

    1999-08-01

    A case study evaluates the economics of installing a staged evaporative cooling system in a factory in the southeastern USA. The effective temperature at the plant floor is predicted for each working hour from typical meteorological year data. The analysis accounts for internal loads and moisture evaporated by the manufacturing process. Worker productivity is estimated from the effective temperature. Several building loads and evaporative cooling system designs are considered. The results show that evaporative air conditioning can improve worker productivity and profit margins in manufacturing facilities that have high internal loads, high ventilation requirements, or other plant-specific conditions that would make conventional air conditioning uneconomical.

  19. Portable brine evaporator unit, process, and system

    DOEpatents

    Hart, Paul John; Miller, Bruce G.; Wincek, Ronald T.; Decker, Glenn E.; Johnson, David K.

    2009-04-07

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

  20. 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).

  1. Evaporation by mechanical vapor compression

    NASA Astrophysics Data System (ADS)

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

    A review of existing technology and application of the mechanical vapor recompression and falling film evaporation in both the sugar and nonsugar industries, and the potential of application to the domestic beet sugar industry is made. Upon assimilating the information gathered, certain design guidelines were established, possible candidate factories for a demonstration project were identified, and a preliminary technical and economic evaluation of the sites was made. The Nampa, Idaho plant of the Amalgamated Sugar Company was selected as the most amenable from the standpoint of technical compatibility, the most attractive on investment and the enthusiasm of the management. Preliminary engineering was done for the Nampa site, permitting a reasonably definitive installed cost estimate to be made.

  2. 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.

  3. Portion of Enhanced 360-degree Gallery Pan

    NASA Technical Reports Server (NTRS)

    1997-01-01

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

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

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

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

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

  4. The Potential of panHER Inhibition in Cancer

    PubMed Central

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

    2015-01-01

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

  5. 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.

  6. The ATLAS PanDA Monitoring System and its Evolution

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    USGS Publications Warehouse

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

    1987-01-01

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

  8. Congruent evaporation temperature of GaAs(001) controlled by As flux

    SciTech Connect

    Zhou, Z. Y.; Zheng, C. X.; Tang, W. X.; Jesson, D. E.; Tersoff, J.

    2010-09-20

    The congruent evaporation temperature T{sub c} is a fundamental surface characteristic of GaAs and similar compounds. Above T{sub c} the rate of As evaporation exceeds that of Ga during Langmuir (free) evaporation into a vacuum. However, during molecular beam epitaxy (MBE) there is generally an external As flux F incident on the surface. Here we show that this flux directly controls T{sub c}. We introduce a sensitive approach to measure T{sub c} based on Ga droplet stability, and determine the dependence of T{sub c} on F. This dependence is explained by a simple model for evaporation in the presence of external flux. The capability of manipulating T{sub c} via changing F offers a means of controlling congruent evaporation with relevance to MBE, surface preparation methods, and droplet epitaxy.

  9. Kinetics of evaporation and gel formation in thin films of ceramic precursors.

    PubMed

    Gu, Yu; Chen, Zhaoxi; Borodinov, Nikolay; Luzinov, Igor; Peng, Fei; Kornev, Konstantin G

    2014-12-01

    Precursors derived from the hydrolysis of organic or inorganic salts have been widely used to produce ceramic coatings for a broad variety of applications. When applying the liquid precursors to the substrates, it is extremely challenging to control the film uniformity and homogeneity. The rate of solvent evaporation at different locations is different, causing the viscosity variation and flows in the film. There is very limited knowledge about the viscosity change in evaporating ceramic precursors. Therefore, it is crucial to understand the effect of evaporation on viscosity variation in thin films and droplets. We use magnetic rotational spectroscopy to study the time dependence of viscosity in mullite precursors. A correlation between the viscosity change and evaporation kinetics is revealed. This correlation was used to relate the change of viscosity to the concentration of mullite. A master curve relating viscosity to the mullite concentration was constructed and used to propose a possible scenario of the viscosity increase during solvent evaporation. PMID:25397585

  10. Molecular dynamics simulations of evaporation-induced nanoparticle assembly

    NASA Astrophysics Data System (ADS)

    Cheng, Shengfeng; Grest, Gary S.

    2013-02-01

    While evaporating solvent is a widely used technique to assemble nano-sized objects into desired superstructures, there has been limited work on how the assembled structures are affected by the physical aspects of the process. We present large scale molecular dynamics simulations of the evaporation-induced assembly of nanoparticles suspended in a liquid that evaporates in a controlled fashion. The quality of the nanoparticle crystal formed just below the liquid/vapor interface is found to be better at relatively slower evaporation rates, as less defects and grain boundaries appear. This trend is understood as the result of the competition between the accumulation and diffusion times of nanoparticles at the liquid/vapor interface. When the former is smaller, nanoparticles are deposited so fast at the interface that they do not have sufficient time to arrange through diffusion, which leads to the prevalence of defects and grain boundaries. Our results have important implications in understanding assembly of nanoparticles and colloids in non-equilibrium liquid environments.

  11. Nanosecond laser-induced thermal evaporation of silicon carbide

    SciTech Connect

    Reitano, R.; Baeri, P.

    1996-09-01

    Excimer (XeCl) laser pulses, 15 ns in duration and with fluences up to 10 J cm{sup {minus}2}, have been employed to induce melting and evaporation of 6H SiC thin layers in vacuum. Sample surface modification in the nanosecond time scale have been monitorized in situ by optical probing. Eventually, the ablation product was collected on silicon single-crystal substrates placed in front of the SiC target. Modeling of the heating and the thermal evaporation processes resulted in estimation of surface temperatures as high as 10,000 K, evaporation rates of the order of 10{sup 25} molecules cm{sup {minus}2} s{sup {minus}1} and recoil pressures of the order of 1 GPa. Comparison with experiments showed that the simple mechanism of purely thermal evaporation is able to describe the process of particle removal from a surface by short laser pulses only in the low-energy density range. Above a certain threshold the model breaks down and other mechanisms have to be considered.

  12. 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.

  13. The structure of evaporating and combusting sprays: Measurements and predictions

    NASA Technical Reports Server (NTRS)

    Shuen, J. S.; Solomon, A. S. P.; Faeth, F. M.

    1983-01-01

    The structure of particle-laden jets and nonevaporating and evaporating sprays was measured in order to evaluate models of these processes. Three models are being evaluated: (1) a locally homogeneous flow model, where slip between the phases is neglected and the flow is assumed to be in local thermodynamic equilibrium; (2) a deterministic separated flow model, where slip and finite interphase transport rates are considered but effects of particle/drop dispersion by turbulence and effects of turbulence on interphase transport rates are ignored; and (3) a stochastic separated flow model, where effects of interphase slip, turbulent dispersion and turbulent fluctuations are considered using random sampling for turbulence properties in conjunction with random-walk computations for particle motion. All three models use a k-e-g turbulence model. All testing and data reduction are completed for the particle laden jets. Mean and fluctuating velocities of the continuous phase and mean mixture fraction were measured in the evaporating sprays.

  14. Evaluation of a locally homogeneous model of spray evaporation

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  15. Pan-FGFR inhibition leads to blockade of FGF23 signaling, soft tissue mineralization, and cardiovascular dysfunction.

    PubMed

    Yanochko, Gina M; Vitsky, Allison; Heyen, Jonathan R; Hirakawa, Brad; Lam, Justine L; May, Jeff; Nichols, Tim; Sace, Frederick; Trajkovic, Dusko; Blasi, Eileen

    2013-10-01

    The fibroblast growth factor receptors (FGFR) play a major role in angiogenesis and are desirable targets for the development of therapeutics. Groups of Wistar Han rats were dosed orally once daily for 4 days with a small molecule pan-FGFR inhibitor (5mg/kg) or once daily for 6 days with a small molecule MEK inhibitor (3mg/kg). Serum phosphorous and FGF23 levels increased in all rats during the course of the study. Histologically, rats dosed with either drug exhibited multifocal, multiorgan soft tissue mineralization. Expression levels of the sodium phosphate transporter Npt2a and the vitamin D-metabolizing enzymes Cyp24a1 and Cyp27b1 were modulated in kidneys of animals dosed with the pan-FGFR inhibitor. Both inhibitors decreased ERK phosphorylation in the kidneys and inhibited FGF23-induced ERK phosphorylation in vitro in a dose-dependent manner. A separate cardiovascular outcome study was performed to monitor hemodynamics and cardiac structure and function of telemetered rats dosed with either the pan-FGFR inhibitor or MEK inhibitor for 3 days. Both compounds increased blood pressure (~+ 17 mmHg), decreased heart rate (~-75 bpm), and modulated echocardiography parameters. Our data suggest that inhibition of FGFR signaling following administration of either pan-FGFR inhibitor or MEK inhibitor interferes with the FGF23 pathway, predisposing animals to hyperphosphatemia and a tumoral calcinosis-like syndrome in rodents. PMID:23872713

  16. On the Resistance to Transpiration of the Sites of Evaporation within the Leaf.

    PubMed

    Farquhar, G D; Raschke, K

    1978-06-01

    The rates of transpiration from the upper and lower surfaces of leaves of Gossypium hirsutum, Xanthium strumarium, and Zea mays were compared with the rates at which helium diffused across those leaves. There was no evidence for effects of CO(2) concentration or rate of evaporation on the resistance to water loss from the evaporating surface ("resistance of the mesophyll wall to transpiration") and no evidence for any significant wall resistance in turgid tissues. The possible existence of a wall resistance was also tested in leaves of Commelina communis and Tulipa gesneriana whose epidermis could be easily peeled. Only when an epidermis was removed from a leaf, evaporation from the mesophyll tissue declined. We conclude that under conditions relevant to studies of stomatal behavior, the water vapor pressure at the sites of evaporation is equal to the saturation vapor pressure. PMID:16660404

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

    NASA Technical Reports Server (NTRS)

    Wallace, D.; Sagan, C.

    1979-01-01

    The existence of ice covered rivers on Mars is considered. It is noted that the evaporation rate of water ice on the surface of a planet with an atmosphere involves an equilibrium between solar heating and radiative and evaporative cooling of the ice layer. It is determined that even with a mean Martian insolation rate above the ice of approximately 10 to the -8th g per sq cm/sec, a flowing channel of liquid water will be covered by ice which evaporates sufficiently slowly that the water below can flow for hundreds of kilometers even with modest discharges. Evaporation rates are calculated for a range of frictional velocities, atmospheric pressures, and insolations and it is suggested that some subset of observed Martian channels may have formed as ice-choked rivers. Finally, the exobiological implications of ice covered channels or lakes on Mars are discussed.

  18. Hollow Fiber Ground Evaporator Unit Testing

    NASA Technical Reports Server (NTRS)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus

    2010-01-01

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

  19. Century Scale Evaporation Trend: An Observational Study

    NASA Technical Reports Server (NTRS)

    Bounoui, Lahouari

    2012-01-01

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

  20. The stability of rapidly growing or evaporating crystals

    NASA Astrophysics Data System (ADS)

    Keller, Joseph B.; Cohen, H. G.; Merchant, G. J.

    1993-04-01

    Solutions for the growth rate of perturbations in the locations of moving steps on a growing or evaporating crystal are presented. They are obtained by solving an equation derived by R. Ghez, H. G. Cohen, and J. B. Keller [J. Appl. Phys. 73, 3685 (1993)] based upon the Burton-Cabrera-Frank theory of crystal growth. They agree with the results derived via the adiabatic approximation when the dimensionless growth rate is small, which shows that those results are correct. However, when the growth rate is large the present exact results differ from those of the adiabatic approximation, as might be expected.

  1. Advanced evaporator technology progress report FY 1992

    SciTech Connect

    Chamberlain, D.; Hutter, J.C.; Leonard, R.A.

    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.

  2. Light geodesics near an evaporating black hole

    NASA Astrophysics Data System (ADS)

    Guerreiro, Thiago; Monteiro, Fernando

    2015-10-01

    Quantum effects imply that an infalling observer cannot cross the event horizon of an evaporating black hole, even in her proper time. The Penrose diagram of an evaporating black hole is different from the one usually reported in the literature. We show that before the observer can cross the horizon the black hole disappears. Possible observational consequences are discussed.

  3. Representational Issues in Students Learning about Evaporation

    ERIC Educational Resources Information Center

    Tytler, Russell; Prain, Vaughan; Peterson, Suzanne

    2007-01-01

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

  4. Survey of lead in canned evaporated milk.

    PubMed

    Capar, S G; Rigsby, E J

    1989-01-01

    A Food and Drug Administration survey of lead in canned evaporated milk conducted in fiscal year 1985/86 found a mean level of 0.006 micrograms Pb/g. This level is much lower than that found in previous surveys and is attributed to the use of nonlead-soldered cans for packaging evaporated milk. PMID:2745360

  5. Structure and optoelectrical properties of photopolymerized PAn/DNA complex

    NASA Astrophysics Data System (ADS)

    Kobayashi, Norihisa; Morimoto, Taro; Ushikubo, Takahiro

    2007-09-01

    A Polyaniline (PAn)/ DNA complex has been successfully prepared by the photopolymerization of dimeric aniline via photocatalytic reaction of Ru(bpy) 3 2+ in the presence of DNA. The reaction occurs even in the solution at pH 3.0 - 6.0, due to the specific local "lower-pH" environment provided by DNA. The PAn in the complex has ordered structure associated with double-helical DNA. The complex contains photocatalyst, Ru(bpy) 3 2+, even after purification and the Ru(bpy) 3 2+ also works as emitting material. A Ru(bpy) 3 2+ complex-based red-emitting diode with a fast turn-on response was successfully fabricated by employing this novel, processable and water-soluble PAn/DNA complex.

  6. Building a pan-genome reference for a population.

    PubMed

    Nguyen, Ngan; Hickey, Glenn; Zerbino, Daniel R; Raney, Brian; Earl, Dent; Armstrong, Joel; Kent, W James; Haussler, David; Paten, Benedict

    2015-05-01

    A reference genome is a high quality individual genome that is used as a coordinate system for the genomes of a population, or genomes of closely related subspecies. Given a set of genomes partitioned by homology into alignment blocks we formalize the problem of ordering and orienting the blocks such that the resulting ordering maximally agrees with the underlying genomes' ordering and orientation, creating a pan-genome reference ordering. We show this problem is NP-hard, but also demonstrate, empirically and within simulations, the performance of heuristic algorithms based upon a cactus graph decomposition to find locally maximal solutions. We describe an extension of our Cactus software to create a pan-genome reference for whole genome alignments, and demonstrate how it can be used to create novel genome browser visualizations using human variation data as a test. In addition, we test the use of a pan-genome for describing variations and as a reference for read mapping. PMID:25565268

  7. Recent Improvements in the ATLAS PanDA Pilot

    NASA Astrophysics Data System (ADS)

    Nilsson, P.; Caballero Bejar, J.; Compostella, G.; Contreras, C.; De, K.; Dos Santos, T.; Maeno, T.; Potekhin, M.; Wenaus, T.

    2012-12-01

    The Production and Distributed Analysis system (PanDA) in the ATLAS experiment uses pilots to execute submitted jobs on the worker nodes. The pilots are designed to deal with different runtime conditions and failure scenarios, and support many storage systems. This talk will give a brief overview of the PanDA pilot system and will present major features and recent improvements including CernVM File System integration, the job retry mechanism, advanced job monitoring including JEM technology, and validation of new pilot code using the HammerCloud stress-testing system. PanDA is used for all ATLAS distributed production and is the primary system for distributed analysis. It is currently used at over 130 sites worldwide. We analyze the performance of the pilot system in processing LHC data on the OSG, EGI and Nordugrid infrastructures used by ATLAS, and describe plans for its further evolution.

  8. 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.

  9. Bioenergy and Biodiversity: Key Lessons from the Pan American Region

    NASA Astrophysics Data System (ADS)

    Kline, Keith L.; Martinelli, Fernanda Silva; Mayer, Audrey L.; Medeiros, Rodrigo; Oliveira, Camila Ortolan F.; Sparovek, Gerd; Walter, Arnaldo; Venier, Lisa A.

    2015-12-01

    Understanding how large-scale bioenergy production can affect biodiversity and ecosystems is important if society is to meet current and future sustainable development goals. A variety of bioenergy production systems have been established within different contexts throughout the Pan American region, with wide-ranging results in terms of documented and projected effects on biodiversity and ecosystems. The Pan American region is home to the majority of commercial bioenergy production and therefore the region offers a broad set of experiences and insights on both conflicts and opportunities for biodiversity and bioenergy. This paper synthesizes lessons learned focusing on experiences in Canada, the United States, and Brazil regarding the conflicts that can arise between bioenergy production and ecological conservation, and benefits that can be derived when bioenergy policies promote planning and more sustainable land-management systems. We propose a research agenda to address priority information gaps that are relevant to biodiversity concerns and related policy challenges in the Pan American region.

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

    PubMed Central

    Lee, Heejeong; Joo, Nami

    2012-01-01

    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

  11. 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

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

    NASA Astrophysics Data System (ADS)

    Shahraeeni, Ebrahim; Or, Dani

    2010-09-01

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

  13. 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.; Rubio, A.; Cohen, M.L. |

    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.

  14. 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.

  15. The future of PanDA in ATLAS distributed computing

    NASA Astrophysics Data System (ADS)

    De, K.; Klimentov, A.; Maeno, T.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Schovancova, J.; Vaniachine, A.; Wenaus, T.

    2015-12-01

    Experiments at the Large Hadron Collider (LHC) face unprecedented computing challenges. Heterogeneous resources are distributed worldwide at hundreds of sites, thousands of physicists analyse the data remotely, the volume of processed data is beyond the exabyte scale, while data processing requires more than a few billion hours of computing usage per year. The PanDA (Production and Distributed Analysis) system was developed to meet the scale and complexity of LHC distributed computing for the ATLAS experiment. In the process, the old batch job paradigm of locally managed computing in HEP was discarded in favour of a far more automated, flexible and scalable model. The success of PanDA in ATLAS is leading to widespread adoption and testing by other experiments. PanDA is the first exascale workload management system in HEP, already operating at more than a million computing jobs per day, and processing over an exabyte of data in 2013. There are many new challenges that PanDA will face in the near future, in addition to new challenges of scale, heterogeneity and increasing user base. PanDA will need to handle rapidly changing computing infrastructure, will require factorization of code for easier deployment, will need to incorporate additional information sources including network metrics in decision making, be able to control network circuits, handle dynamically sized workload processing, provide improved visualization, and face many other challenges. In this talk we will focus on the new features, planned or recently implemented, that are relevant to the next decade of distributed computing workload management using PanDA.

  16. Exploration of quantitative kinetic models for the evaporation of silicate melts in vacuum and in hydrogen

    NASA Astrophysics Data System (ADS)

    Alexander, C. M. O'd.

    2001-02-01

    Two basic approaches (pure component reference (PCR) and equilibrium reference (EQR)) to modeling silicate melt evaporation are explored. The PCR model calculates the maximum possible evaporation rates of the pure oxides from their equilibrium vapor pressures and rescales these rates according to the activities of the oxides in the silicate melts and the melt densities. The EQR model calculates the maximum possible evaporation rates based on the equilibrium vapor pressures of the melts. Differences between the calculated and experimentally determined evaporation rates are accounted for with evaporation (aevap) coefficients that are only dependent on temperature. Two versions of the PCR model, Cases 1 and 2, are explored to try to resolve apparently contradictory conclusions about the composition of the evaporating species based on Mg and Si isotope fractionation during evaporation (species are not in thermodynamic equilibrium proportions) and direct measurements of gas species in Langmuir experiments (species are in roughly equilibrium proportions). The Case 2 and EQR models cannot explain the observed isotope fractionations unless evaporation occurred under non-Rayleigh conditions, either because there was significant recondensation during the experiments or because diffusion was playing a limiting role. Whether or not the role of diffusion is included, the PCR and EQR models are able to reproduce the elemental results of evaporation experiments of "chondritic" melts from temperatures of 1700 to 2000 #C, and up to mass losses of about 95%. However, the models underestimate absolute evaporation rates in very Ca- and Al-rich melts. This may reflect errors in the model used to estimate oxide activities. The EQR model can only reproduce the observed evaporation behavior of Na if, unlike the other oxides, its aevap coefficient is close to unity. Based on available diffusion data, diffusion is not slow enough in "chondritic" or forsteritic melts to explain the isotopic fractionations of Mg and O in the evaporation experiments, but it may play a role in limiting Si isotope fractionation. Provided recondensation was not a significant factor in the experiments, at present PCR Case 1 appears to be the best model if both the Langmuir and the isotopic fractionation experiments are to be explained.

  17. Low-density microcellular carbonized polyacrylonitrile (PAN) foams

    SciTech Connect

    Sylwester, A.P.

    1988-01-01

    Carbon foams are of interest for numerous applications including: porous electrodes, filters, high temperature insulation, catalyst supports, and as structural materials for the fabrication of inertial confinement fusion targets. Carbon foams have improved thermal and chemical stability when compared to polymer foams and provide improved dimensional stability. We have reported a new process for preparing carbon foams which involves the preparation of low-density PAN foams which can be carbonized. The unique properties of these materials and several developing applications for carbonized PAN foams are described. 3 refs., 6 figs., 2 tabs.

  18. Age-related decline in ovarian follicle stocks differ between chimpanzees (Pan troglodytes) and humans.

    PubMed

    Cloutier, Christina T; Coxworth, James E; Hawkes, Kristen

    2015-02-01

    Similarity in oldest parturitions in humans and great apes suggests that we maintain ancestral rates of ovarian aging. Consistent with that hypothesis, previous counts of primordial follicles in postmortem ovarian sections from chimpanzees (Pan troglodytes) showed follicle stock decline at the same rate that human stocks decline across the same ages. Here, we correct that finding with a chimpanzee sample more than three times larger than the previous one, which also allows comparison into older ages. Analyses show depletion rates similar until about age 35, but after 35, the human counts continue to fall with age, while the change is much less steep in chimpanzees. This difference implicates likely effects on ovarian dynamics from other physiological systems that are senescing at different rates, and, potentially, different perimenopausal experience for chimpanzees and humans. PMID:25651885

  19. Mergers, cooling flows, and evaporation

    NASA Technical Reports Server (NTRS)

    Sparks, W. B.

    1993-01-01

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

  20. Ion-pair evaporation from ionic liquid clusters.

    PubMed

    Hogan, Christopher J; Fernandez de la Mora, Juan

    2010-08-01

    A differential mobility analyzer (DMA) is used in atmospheric pressure N(2) to select a narrow range of electrical mobilities from a complex mix of cluster ions of composition (CA)(n)(C(+))(z). The clusters are introduced into the N(2) gas by electrospraying concentrated (approximately 20 mM) acetonitrile solutions of ionic liquids (molten salts) of composition CA (C(+) = cation, A(-) = anion). Mass analysis of these mobility-selected ions reveals the occurrence of individual neutral ion-pair evaporation events from the smallest singly charged clusters: (CA)(n)C(+)-->(CA)(n-1)C(+)+CA. Although bulk ionic liquids are effectively involatile at room temperature, up to six sequential evaporation events are observed. Because this requires far more internal energy than available in the original clusters, substantial heating (approximately 10 eV) must take place in the ion guides leading to the mass analyzer. The observed increase in IL evaporation rate with decreasing size is drastic, in qualitative agreement with the exponential vapor pressure dependence predicted by Kelvin's formula. A single evaporation event is barely detectable at n = 13, while two or more are prominent for n < or = 9. Magic number clusters (CA)(4)C(+) with singularly low volatilities are found in three of the four ionic liquids studied. Like their recently reported liquid phase prenucleation cluster analogs, these magic number clusters could play a key role as gas-phase nucleation seeds. All the singularly involatile clusters seen are cations, which may help understand commonly observed sign effects in ion-induced nucleation. No other charge-sign asymmetry is seen on cluster evaporation. PMID:20447834